+++ /dev/null
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-.\" ======================================================================
-.\"
-.IX Title "GCC 1"
-.TH GCC 1 "gcc-3.1" "2001-06-25" "GNU"
-.UC
-.SH "NAME"
-gcc \- \s-1GNU\s0 project C and \*(C+ compiler
-.SH "SYNOPSIS"
-.IX Header "SYNOPSIS"
-gcc [\fB\-c\fR|\fB\-S\fR|\fB\-E\fR] [\fB\-std=\fR\fIstandard\fR]
- [\fB\-g\fR] [\fB\-pg\fR] [\fB\-O\fR\fIlevel\fR]
- [\fB\-W\fR\fIwarn\fR...] [\fB\-pedantic\fR]
- [\fB\-I\fR\fIdir\fR...] [\fB\-L\fR\fIdir\fR...]
- [\fB\-D\fR\fImacro\fR[=\fIdefn\fR]...] [\fB\-U\fR\fImacro\fR]
- [\fB\-f\fR\fIoption\fR...] [\fB\-m\fR\fImachine-option\fR...]
- [\fB\-o\fR \fIoutfile\fR] \fIinfile\fR...
-.PP
-Only the most useful options are listed here; see below for the
-remainder. \fBg++\fR accepts mostly the same options as \fBgcc\fR.
-.SH "DESCRIPTION"
-.IX Header "DESCRIPTION"
-When you invoke \s-1GCC\s0, it normally does preprocessing, compilation,
-assembly and linking. The ``overall options'' allow you to stop this
-process at an intermediate stage. For example, the \fB\-c\fR option
-says not to run the linker. Then the output consists of object files
-output by the assembler.
-.PP
-Other options are passed on to one stage of processing. Some options
-control the preprocessor and others the compiler itself. Yet other
-options control the assembler and linker; most of these are not
-documented here, since you rarely need to use any of them.
-.PP
-Most of the command line options that you can use with \s-1GCC\s0 are useful
-for C programs; when an option is only useful with another language
-(usually \*(C+), the explanation says so explicitly. If the description
-for a particular option does not mention a source language, you can use
-that option with all supported languages.
-.PP
-The \fBgcc\fR program accepts options and file names as operands. Many
-options have multi-letter names; therefore multiple single-letter options
-may \fInot\fR be grouped: \fB\-dr\fR is very different from \fB\-d\ \-r\fR.
-.PP
-You can mix options and other arguments. For the most part, the order
-you use doesn't matter. Order does matter when you use several options
-of the same kind; for example, if you specify \fB\-L\fR more than once,
-the directories are searched in the order specified.
-.PP
-Many options have long names starting with \fB\-f\fR or with
-\&\fB\-W\fR\-\-\-for example, \fB\-fforce-mem\fR,
-\&\fB\-fstrength-reduce\fR, \fB\-Wformat\fR and so on. Most of
-these have both positive and negative forms; the negative form of
-\&\fB\-ffoo\fR would be \fB\-fno-foo\fR. This manual documents
-only one of these two forms, whichever one is not the default.
-.SH "OPTIONS"
-.IX Header "OPTIONS"
-.Sh "Option Summary"
-.IX Subsection "Option Summary"
-Here is a summary of all the options, grouped by type. Explanations are
-in the following sections.
-.Ip "\fIOverall Options\fR" 4
-.IX Item "Overall Options"
-\&\fB\-c \-S \-E \-o\fR \fIfile\fR \fB\-pipe \-pass-exit-codes \-x\fR \fIlanguage\fR
-\&\fB\-v \-\-target-help \-\-help\fR
-.Ip "\fIC Language Options\fR" 4
-.IX Item "C Language Options"
-\&\fB\-ansi \-std=\fR\fIstandard\fR \fB\-aux-info\fR \fIfilename\fR
-\&\fB\-fno-asm \-fno-builtin
-\&\-fhosted \-ffreestanding
-\&\-trigraphs \-traditional \-traditional-cpp
-\&\-fallow-single-precision \-fcond-mismatch
-\&\-fsigned-bitfields \-fsigned-char
-\&\-funsigned-bitfields \-funsigned-char
-\&\-fwritable-strings \-fshort-wchar\fR
-.Ip "\fI\*(C+ Language Options\fR" 4
-.IX Item " Language Options"
-\&\fB\-fno-access-control \-fcheck-new \-fconserve-space
-\&\-fno-const-strings \-fdollars-in-identifiers
-\&\-fno-elide-constructors
-\&\-fno-enforce-eh-specs \-fexternal-templates
-\&\-falt-external-templates
-\&\-ffor-scope \-fno-for-scope \-fno-gnu-keywords \-fno-honor-std
-\&\-fno-implicit-templates
-\&\-fno-implicit-inline-templates
-\&\-fno-implement-inlines \-fms-extensions
-\&\-fno-nonansi-builtins \-fno-operator-names
-\&\-fno-optional-diags \-fpermissive
-\&\-frepo \-fno-rtti \-fstats \-ftemplate-depth-\fR\fIn\fR
-\&\fB\-fuse-cxa-atexit \-fvtable-gc \-fno-weak \-nostdinc++
-\&\-fno-default-inline \-Wctor-dtor-privacy
-\&\-Wnon-virtual-dtor \-Wreorder
-\&\-Weffc++ \-Wno-deprecated
-\&\-Wno-non-template-friend \-Wold-style-cast
-\&\-Woverloaded-virtual \-Wno-pmf-conversions
-\&\-Wsign-promo \-Wsynth\fR
-.Ip "\fIObjective-C Language Options\fR" 4
-.IX Item "Objective-C Language Options"
-\&\fB\-fconstant-string-class=\fR\fIclass-name\fR
-\&\fB\-fgnu-runtime \-fnext-runtime \-gen-decls
-\&\-Wno-protocol \-Wselector\fR
-.Ip "\fILanguage Independent Options\fR" 4
-.IX Item "Language Independent Options"
-\&\fB\-fmessage-length=\fR\fIn\fR
-\&\fB\-fdiagnostics-show-location=\fR[\fBonce\fR|\fBevery-line\fR]
-.Ip "\fIWarning Options\fR" 4
-.IX Item "Warning Options"
-\&\fB\-fsyntax-only \-pedantic \-pedantic-errors
-\&\-w \-W \-Wall \-Waggregate-return
-\&\-Wcast-align \-Wcast-qual \-Wchar-subscripts \-Wcomment
-\&\-Wconversion \-Wdisabled-optimization \-Werror
-\&\-Wfloat-equal \-Wformat \-Wformat=2
-\&\-Wformat-nonliteral \-Wformat-security
-\&\-Wimplicit \-Wimplicit-int
-\&\-Wimplicit-function-declaration
-\&\-Werror-implicit-function-declaration
-\&\-Wimport \-Winline
-\&\-Wlarger-than-\fR\fIlen\fR \fB\-Wlong-long
-\&\-Wmain \-Wmissing-braces \-Wmissing-declarations
-\&\-Wmissing-format-attribute \-Wmissing-noreturn
-\&\-Wmultichar \-Wno-format-extra-args \-Wno-format-y2k
-\&\-Wno-import \-Wpacked \-Wpadded
-\&\-Wparentheses \-Wpointer-arith \-Wredundant-decls
-\&\-Wreturn-type \-Wsequence-point \-Wshadow
-\&\-Wsign-compare \-Wswitch \-Wsystem-headers
-\&\-Wtrigraphs \-Wundef \-Wuninitialized
-\&\-Wunknown-pragmas \-Wunreachable-code
-\&\-Wunused \-Wunused-function \-Wunused-label \-Wunused-parameter
-\&\-Wunused-value \-Wunused-variable \-Wwrite-strings\fR
-.Ip "\fIC-only Warning Options\fR" 4
-.IX Item "C-only Warning Options"
-\&\fB\-Wbad-function-cast \-Wmissing-prototypes \-Wnested-externs
-\&\-Wstrict-prototypes \-Wtraditional\fR
-.Ip "\fIDebugging Options\fR" 4
-.IX Item "Debugging Options"
-\&\fB\-a \-ax \-d\fR\fIletters\fR \fB\-dumpspecs \-dumpmachine \-dumpversion
-\&\-fdump-unnumbered \-fdump-translation-unit\fR[\fB-\fR\fIn\fR] \fB\-fdump-class-hierarchy\fR[\fB-\fR\fIn\fR]
-\&\fB\-fdump-ast-original\fR[\fB-\fR\fIn\fR] \fB\-fdump-ast-optimized\fR[\fB-\fR\fIn\fR]
-\&\fB\-fmem-report \-fpretend-float
-\&\-fprofile-arcs \-ftest-coverage \-ftime-report
-\&\-g \-g\fR\fIlevel\fR \fB\-gcoff \-gdwarf \-gdwarf-1 \-gdwarf-1+ \-gdwarf-2
-\&\-ggdb \-gstabs \-gstabs+ \-gxcoff \-gxcoff+
-\&\-p \-pg \-print-file-name=\fR\fIlibrary\fR \fB\-print-libgcc-file-name
-\&\-print-multi-directory \-print-multi-lib
-\&\-print-prog-name=\fR\fIprogram\fR \fB\-print-search-dirs \-Q
-\&\-save-temps \-time\fR
-.Ip "\fIOptimization Options\fR" 4
-.IX Item "Optimization Options"
-\&\fB\-falign-functions=\fR\fIn\fR \fB\-falign-jumps=\fR\fIn\fR
-\&\fB\-falign-labels=\fR\fIn\fR \fB\-falign-loops=\fR\fIn\fR
-\&\fB\-fbranch-probabilities \-fcaller-saves
-\&\-fcse-follow-jumps \-fcse-skip-blocks \-fdata-sections \-fdce
-\&\-fdelayed-branch \-fdelete-null-pointer-checks
-\&\-fexpensive-optimizations \-ffast-math \-ffloat-store
-\&\-fforce-addr \-fforce-mem \-ffunction-sections
-\&\-fgcse \-fgcse-lm \-fgcse-sm
-\&\-finline-functions \-finline-limit=\fR\fIn\fR \fB\-fkeep-inline-functions
-\&\-fkeep-static-consts \-fmove-all-movables
-\&\-fno-default-inline \-fno-defer-pop
-\&\-fno-function-cse \-fno-guess-branch-probability
-\&\-fno-inline \-fno-math-errno \-fno-peephole \-fno-peephole2
-\&\-funsafe-math-optimizations \-fno-trapping-math
-\&\-fomit-frame-pointer \-foptimize-register-move
-\&\-foptimize-sibling-calls \-freduce-all-givs
-\&\-fregmove \-frename-registers
-\&\-frerun-cse-after-loop \-frerun-loop-opt
-\&\-fschedule-insns \-fschedule-insns2
-\&\-fsingle-precision-constant \-fssa
-\&\-fstrength-reduce \-fstrict-aliasing \-fthread-jumps \-ftrapv
-\&\-funroll-all-loops \-funroll-loops
-\&\-\-param\fR \fIname\fR\fB=\fR\fIvalue\fR
-\&\fB\-O \-O0 \-O1 \-O2 \-O3 \-Os\fR
-.Ip "\fIPreprocessor Options\fR" 4
-.IX Item "Preprocessor Options"
-\&\fB\-$ \-A\fR\fIquestion\fR\fB=\fR\fIanswer\fR \fB\-A-\fR\fIquestion\fR[\fB=\fR\fIanswer\fR]
-\&\fB\-C \-dD \-dI \-dM \-dN
-\&\-D\fR\fImacro\fR[\fB=\fR\fIdefn\fR] \fB\-E \-H
-\&\-idirafter\fR \fIdir\fR
-\&\fB\-include\fR \fIfile\fR \fB\-imacros\fR \fIfile\fR
-\&\fB\-iprefix\fR \fIfile\fR \fB\-iwithprefix\fR \fIdir\fR
-\&\fB\-iwithprefixbefore\fR \fIdir\fR \fB\-isystem\fR \fIdir\fR
-\&\fB\-M \-MM \-MF \-MG \-MP \-MQ \-MT \-nostdinc \-P \-remap
-\&\-trigraphs \-undef \-U\fR\fImacro\fR \fB\-Wp,\fR\fIoption\fR
-.Ip "\fIAssembler Option\fR" 4
-.IX Item "Assembler Option"
-\&\fB\-Wa,\fR\fIoption\fR
-.Ip "\fILinker Options\fR" 4
-.IX Item "Linker Options"
-\&\fB
-\&\fR\fIobject-file-name\fR \fB\-l\fR\fIlibrary\fR
-\&\fB\-nostartfiles \-nodefaultlibs \-nostdlib
-\&\-s \-static \-static-libgcc \-shared \-shared-libgcc \-symbolic
-\&\-Wl,\fR\fIoption\fR \fB\-Xlinker\fR \fIoption\fR
-\&\fB\-u\fR \fIsymbol\fR
-.Ip "\fIDirectory Options\fR" 4
-.IX Item "Directory Options"
-\&\fB\-B\fR\fIprefix\fR \fB\-I\fR\fIdir\fR \fB\-I- \-L\fR\fIdir\fR \fB\-specs=\fR\fIfile\fR
-.Ip "\fITarget Options\fR" 4
-.IX Item "Target Options"
-\&\fB\-b\fR \fImachine\fR \fB\-V\fR \fIversion\fR
-.Ip "\fIMachine Dependent Options\fR" 4
-.IX Item "Machine Dependent Options"
-\&\fIM680x0 Options\fR
-.Sp
-\&\fB\-m68000 \-m68020 \-m68020\-40 \-m68020\-60 \-m68030 \-m68040
-\&\-m68060 \-mcpu32 \-m5200 \-m68881 \-mbitfield \-mc68000 \-mc68020
-\&\-mfpa \-mnobitfield \-mrtd \-mshort \-msoft-float \-mpcrel
-\&\-malign-int \-mstrict-align\fR
-.Sp
-\&\fIM68hc1x Options\fR
-.Sp
-\&\fB\-m6811 \-m6812 \-m68hc11 \-m68hc12
-\&\-mauto-incdec \-mshort \-msoft-reg-count=\fR\fIcount\fR
-.Sp
-\&\fI\s-1VAX\s0 Options\fR
-.Sp
-\&\fB\-mg \-mgnu \-munix\fR
-.Sp
-\&\fI\s-1SPARC\s0 Options\fR
-.Sp
-\&\fB\-mcpu=\fR\fIcpu-type\fR
-\&\fB\-mtune=\fR\fIcpu-type\fR
-\&\fB\-mcmodel=\fR\fIcode-model\fR
-\&\fB\-m32 \-m64
-\&\-mapp-regs \-mbroken-saverestore \-mcypress
-\&\-mepilogue \-mfaster-structs \-mflat
-\&\-mfpu \-mhard-float \-mhard-quad-float
-\&\-mimpure-text \-mlive-g0 \-mno-app-regs
-\&\-mno-epilogue \-mno-faster-structs \-mno-flat \-mno-fpu
-\&\-mno-impure-text \-mno-stack-bias \-mno-unaligned-doubles
-\&\-msoft-float \-msoft-quad-float \-msparclite \-mstack-bias
-\&\-msupersparc \-munaligned-doubles \-mv8\fR
-.Sp
-\&\fIConvex Options\fR
-.Sp
-\&\fB\-mc1 \-mc2 \-mc32 \-mc34 \-mc38
-\&\-margcount \-mnoargcount
-\&\-mlong32 \-mlong64
-\&\-mvolatile-cache \-mvolatile-nocache\fR
-.Sp
-\&\fI\s-1AMD29K\s0 Options\fR
-.Sp
-\&\fB\-m29000 \-m29050 \-mbw \-mnbw \-mdw \-mndw
-\&\-mlarge \-mnormal \-msmall
-\&\-mkernel-registers \-mno-reuse-arg-regs
-\&\-mno-stack-check \-mno-storem-bug
-\&\-mreuse-arg-regs \-msoft-float \-mstack-check
-\&\-mstorem-bug \-muser-registers\fR
-.Sp
-\&\fI\s-1ARM\s0 Options\fR
-.Sp
-\&\fB\-mapcs-frame \-mno-apcs-frame
-\&\-mapcs-26 \-mapcs-32
-\&\-mapcs-stack-check \-mno-apcs-stack-check
-\&\-mapcs-float \-mno-apcs-float
-\&\-mapcs-reentrant \-mno-apcs-reentrant
-\&\-msched-prolog \-mno-sched-prolog
-\&\-mlittle-endian \-mbig-endian \-mwords-little-endian
-\&\-malignment-traps \-mno-alignment-traps
-\&\-msoft-float \-mhard-float \-mfpe
-\&\-mthumb-interwork \-mno-thumb-interwork
-\&\-mcpu=\fR\fIname\fR \fB\-march=\fR\fIname\fR \fB\-mfpe=\fR\fIname\fR
-\&\fB\-mstructure-size-boundary=\fR\fIn\fR
-\&\fB\-mbsd \-mxopen \-mno-symrename
-\&\-mabort-on-noreturn
-\&\-mlong-calls \-mno-long-calls
-\&\-msingle-pic-base \-mno-single-pic-base
-\&\-mpic-register=\fR\fIreg\fR
-\&\fB\-mnop-fun-dllimport
-\&\-mpoke-function-name
-\&\-mthumb \-marm
-\&\-mtpcs-frame \-mtpcs-leaf-frame
-\&\-mcaller-super-interworking \-mcallee-super-interworking\fR
-.Sp
-\&\fI\s-1MN10200\s0 Options\fR
-.Sp
-\&\fB\-mrelax\fR
-.Sp
-\&\fI\s-1MN10300\s0 Options\fR
-.Sp
-\&\fB\-mmult-bug \-mno-mult-bug
-\&\-mam33 \-mno-am33
-\&\-mno-crt0 \-mrelax\fR
-.Sp
-\&\fIM32R/D Options\fR
-.Sp
-\&\fB\-mcode-model=\fR\fImodel-type\fR \fB\-msdata=\fR\fIsdata-type\fR
-\&\fB\-G\fR \fInum\fR
-.Sp
-\&\fIM88K Options\fR
-.Sp
-\&\fB\-m88000 \-m88100 \-m88110 \-mbig-pic
-\&\-mcheck-zero-division \-mhandle-large-shift
-\&\-midentify-revision \-mno-check-zero-division
-\&\-mno-ocs-debug-info \-mno-ocs-frame-position
-\&\-mno-optimize-arg-area \-mno-serialize-volatile
-\&\-mno-underscores \-mocs-debug-info
-\&\-mocs-frame-position \-moptimize-arg-area
-\&\-mserialize-volatile \-mshort-data-\fR\fInum\fR \fB\-msvr3
-\&\-msvr4 \-mtrap-large-shift \-muse-div-instruction
-\&\-mversion-03.00 \-mwarn-passed-structs\fR
-.Sp
-\&\fI\s-1RS/6000\s0 and PowerPC Options\fR
-.Sp
-\&\fB\-mcpu=\fR\fIcpu-type\fR
-\&\fB\-mtune=\fR\fIcpu-type\fR
-\&\fB\-mpower \-mno-power \-mpower2 \-mno-power2
-\&\-mpowerpc \-mpowerpc64 \-mno-powerpc
-\&\-mpowerpc-gpopt \-mno-powerpc-gpopt
-\&\-mpowerpc-gfxopt \-mno-powerpc-gfxopt
-\&\-mnew-mnemonics \-mold-mnemonics
-\&\-mfull-toc \-mminimal-toc \-mno-fop-in-toc \-mno-sum-in-toc
-\&\-m64 \-m32 \-mxl-call \-mno-xl-call \-mthreads \-mpe
-\&\-msoft-float \-mhard-float \-mmultiple \-mno-multiple
-\&\-mstring \-mno-string \-mupdate \-mno-update
-\&\-mfused-madd \-mno-fused-madd \-mbit-align \-mno-bit-align
-\&\-mstrict-align \-mno-strict-align \-mrelocatable
-\&\-mno-relocatable \-mrelocatable-lib \-mno-relocatable-lib
-\&\-mtoc \-mno-toc \-mlittle \-mlittle-endian \-mbig \-mbig-endian
-\&\-mcall-aix \-mcall-sysv \-mprototype \-mno-prototype
-\&\-msim \-mmvme \-mads \-myellowknife \-memb \-msdata
-\&\-msdata=\fR\fIopt\fR \fB\-mvxworks \-G\fR \fInum\fR
-.Sp
-\&\fI\s-1RT\s0 Options\fR
-.Sp
-\&\fB\-mcall-lib-mul \-mfp-arg-in-fpregs \-mfp-arg-in-gregs
-\&\-mfull-fp-blocks \-mhc-struct-return \-min-line-mul
-\&\-mminimum-fp-blocks \-mnohc-struct-return\fR
-.Sp
-\&\fI\s-1MIPS\s0 Options\fR
-.Sp
-\&\fB\-mabicalls \-mcpu=\fR\fIcpu-type\fR
-\&\fB\-membedded-data \-muninit-const-in-rodata
-\&\-membedded-pic \-mfp32 \-mfp64 \-mgas \-mgp32 \-mgp64
-\&\-mgpopt \-mhalf-pic \-mhard-float \-mint64 \-mips1
-\&\-mips2 \-mips3 \-mips4 \-mlong64 \-mlong32 \-mlong-calls \-mmemcpy
-\&\-mmips-as \-mmips-tfile \-mno-abicalls
-\&\-mno-embedded-data \-mno-uninit-const-in-rodata
-\&\-mno-embedded-pic \-mno-gpopt \-mno-long-calls
-\&\-mno-memcpy \-mno-mips-tfile \-mno-rnames \-mno-stats
-\&\-mrnames \-msoft-float
-\&\-m4650 \-msingle-float \-mmad
-\&\-mstats \-EL \-EB \-G\fR \fInum\fR \fB\-nocpp
-\&\-mabi=32 \-mabi=n32 \-mabi=64 \-mabi=eabi
-\&\-mfix7000 \-mno-crt0\fR
-.Sp
-\&\fIi386 Options\fR
-.Sp
-\&\fB\-mcpu=\fR\fIcpu-type\fR \fB\-march=\fR\fIcpu-type\fR
-\&\fB\-mintel-syntax \-mieee-fp \-mno-fancy-math-387
-\&\-mno-fp-ret-in-387 \-msoft-float \-msvr3\-shlib
-\&\-mno-wide-multiply \-mrtd \-malign-double
-\&\-mpreferred-stack-boundary=\fR\fInum\fR
-\&\fB\-mthreads \-mno-align-stringops \-minline-all-stringops
-\&\-mpush-args \-maccumulate-outgoing-args \-m128bit-long-double
-\&\-m96bit-long-double \-mregparm=\fR\fInum\fR \fB\-momit-leaf-frame-pointer\fR
-.Sp
-\&\fI\s-1HPPA\s0 Options\fR
-.Sp
-\&\fB\-march=\fR\fIarchitecture-type\fR
-\&\fB\-mbig-switch \-mdisable-fpregs \-mdisable-indexing
-\&\-mfast-indirect-calls \-mgas \-mjump-in-delay
-\&\-mlong-load-store \-mno-big-switch \-mno-disable-fpregs
-\&\-mno-disable-indexing \-mno-fast-indirect-calls \-mno-gas
-\&\-mno-jump-in-delay \-mno-long-load-store
-\&\-mno-portable-runtime \-mno-soft-float
-\&\-mno-space-regs \-msoft-float \-mpa-risc-1\-0
-\&\-mpa-risc-1\-1 \-mpa-risc-2\-0 \-mportable-runtime
-\&\-mschedule=\fR\fIcpu-type\fR \fB\-mspace-regs\fR
-.Sp
-\&\fIIntel 960 Options\fR
-.Sp
-\&\fB\-m\fR\fIcpu-type\fR \fB\-masm-compat \-mclean-linkage
-\&\-mcode-align \-mcomplex-addr \-mleaf-procedures
-\&\-mic-compat \-mic2.0\-compat \-mic3.0\-compat
-\&\-mintel-asm \-mno-clean-linkage \-mno-code-align
-\&\-mno-complex-addr \-mno-leaf-procedures
-\&\-mno-old-align \-mno-strict-align \-mno-tail-call
-\&\-mnumerics \-mold-align \-msoft-float \-mstrict-align
-\&\-mtail-call\fR
-.Sp
-\&\fI\s-1DEC\s0 Alpha Options\fR
-.Sp
-\&\fB\-mfp-regs \-mno-fp-regs \-mno-soft-float \-msoft-float
-\&\-malpha-as \-mgas
-\&\-mieee \-mieee-with-inexact \-mieee-conformant
-\&\-mfp-trap-mode=\fR\fImode\fR \fB\-mfp-rounding-mode=\fR\fImode\fR
-\&\fB\-mtrap-precision=\fR\fImode\fR \fB\-mbuild-constants
-\&\-mcpu=\fR\fIcpu-type\fR
-\&\fB\-mbwx \-mno-bwx \-mcix \-mno-cix \-mmax \-mno-max
-\&\-mmemory-latency=\fR\fItime\fR
-.Sp
-\&\fIClipper Options\fR
-.Sp
-\&\fB\-mc300 \-mc400\fR
-.Sp
-\&\fIH8/300 Options\fR
-.Sp
-\&\fB\-mrelax \-mh \-ms \-mint32 \-malign-300\fR
-.Sp
-\&\fI\s-1SH\s0 Options\fR
-.Sp
-\&\fB\-m1 \-m2 \-m3 \-m3e
-\&\-m4\-nofpu \-m4\-single-only \-m4\-single \-m4
-\&\-mb \-ml \-mdalign \-mrelax
-\&\-mbigtable \-mfmovd \-mhitachi \-mnomacsave
-\&\-mieee \-misize \-mpadstruct \-mspace
-\&\-mprefergot \-musermode\fR
-.Sp
-\&\fISystem V Options\fR
-.Sp
-\&\fB\-Qy \-Qn \-YP,\fR\fIpaths\fR \fB\-Ym,\fR\fIdir\fR
-.Sp
-\&\fI\s-1ARC\s0 Options\fR
-.Sp
-\&\fB\-EB \-EL
-\&\-mmangle-cpu \-mcpu=\fR\fIcpu\fR \fB\-mtext=\fR\fItext-section\fR
-\&\fB\-mdata=\fR\fIdata-section\fR \fB\-mrodata=\fR\fIreadonly-data-section\fR
-.Sp
-\&\fITMS320C3x/C4x Options\fR
-.Sp
-\&\fB\-mcpu=\fR\fIcpu\fR \fB\-mbig \-msmall \-mregparm \-mmemparm
-\&\-mfast-fix \-mmpyi \-mbk \-mti \-mdp-isr-reload
-\&\-mrpts=\fR\fIcount\fR \fB\-mrptb \-mdb \-mloop-unsigned
-\&\-mparallel-insns \-mparallel-mpy \-mpreserve-float\fR
-.Sp
-\&\fIV850 Options\fR
-.Sp
-\&\fB\-mlong-calls \-mno-long-calls \-mep \-mno-ep
-\&\-mprolog-function \-mno-prolog-function \-mspace
-\&\-mtda=\fR\fIn\fR \fB\-msda=\fR\fIn\fR \fB\-mzda=\fR\fIn\fR
-\&\fB\-mv850 \-mbig-switch\fR
-.Sp
-\&\fI\s-1NS32K\s0 Options\fR
-.Sp
-\&\fB\-m32032 \-m32332 \-m32532 \-m32081 \-m32381
-\&\-mmult-add \-mnomult-add \-msoft-float \-mrtd \-mnortd
-\&\-mregparam \-mnoregparam \-msb \-mnosb
-\&\-mbitfield \-mnobitfield \-mhimem \-mnohimem\fR
-.Sp
-\&\fI\s-1AVR\s0 Options\fR
-.Sp
-\&\fB\-mmcu=\fR\fImcu\fR \fB\-msize \-minit-stack=\fR\fIn\fR \fB\-mno-interrupts
-\&\-mcall-prologues \-mno-tablejump \-mtiny-stack\fR
-.Sp
-\&\fIMCore Options\fR
-.Sp
-\&\fB\-mhardlit \-mno-hardlit \-mdiv \-mno-div \-mrelax-immediates
-\&\-mno-relax-immediates \-mwide-bitfields \-mno-wide-bitfields
-\&\-m4byte-functions \-mno-4byte-functions \-mcallgraph-data
-\&\-mno-callgraph-data \-mslow-bytes \-mno-slow-bytes \-mno-lsim
-\&\-mlittle-endian \-mbig-endian \-m210 \-m340 \-mstack-increment\fR
-.Sp
-\&\fI\s-1IA-64\s0 Options\fR
-.Sp
-\&\fB\-mbig-endian \-mlittle-endian \-mgnu-as \-mgnu-ld \-mno-pic
-\&\-mvolatile-asm-stop \-mb-step \-mregister-names \-mno-sdata
-\&\-mconstant-gp \-mauto-pic \-minline-divide-min-latency
-\&\-minline-divide-max-throughput \-mno-dwarf2\-asm
-\&\-mfixed-range=\fR\fIregister-range\fR
-.Ip "\fICode Generation Options\fR" 4
-.IX Item "Code Generation Options"
-\&\fB\-fcall-saved-\fR\fIreg\fR \fB\-fcall-used-\fR\fIreg\fR
-\&\fB\-ffixed-\fR\fIreg\fR \fB\-fexceptions
-\&\-fnon-call-exceptions \-funwind-tables
-\&\-finhibit-size-directive \-finstrument-functions
-\&\-fcheck-memory-usage \-fprefix-function-name
-\&\-fno-common \-fno-ident \-fno-gnu-linker
-\&\-fpcc-struct-return \-fpic \-fPIC
-\&\-freg-struct-return \-fshared-data \-fshort-enums
-\&\-fshort-double \-fvolatile
-\&\-fvolatile-global \-fvolatile-static
-\&\-fverbose-asm \-fpack-struct \-fstack-check
-\&\-fstack-limit-register=\fR\fIreg\fR \fB\-fstack-limit-symbol=\fR\fIsym\fR
-\&\fB\-fargument-alias \-fargument-noalias
-\&\-fargument-noalias-global \-fleading-underscore\fR
-.Sh "Options Controlling the Kind of Output"
-.IX Subsection "Options Controlling the Kind of Output"
-Compilation can involve up to four stages: preprocessing, compilation
-proper, assembly and linking, always in that order. The first three
-stages apply to an individual source file, and end by producing an
-object file; linking combines all the object files (those newly
-compiled, and those specified as input) into an executable file.
-.PP
-For any given input file, the file name suffix determines what kind of
-compilation is done:
-.Ip "\fIfile\fR\fB.c\fR" 4
-.IX Item "file.c"
-C source code which must be preprocessed.
-.Ip "\fIfile\fR\fB.i\fR" 4
-.IX Item "file.i"
-C source code which should not be preprocessed.
-.Ip "\fIfile\fR\fB.ii\fR" 4
-.IX Item "file.ii"
-\&\*(C+ source code which should not be preprocessed.
-.Ip "\fIfile\fR\fB.m\fR" 4
-.IX Item "file.m"
-Objective-C source code. Note that you must link with the library
-\&\fIlibobjc.a\fR to make an Objective-C program work.
-.Ip "\fIfile\fR\fB.mi\fR" 4
-.IX Item "file.mi"
-Objective-C source code which should not be preprocessed.
-.Ip "\fIfile\fR\fB.h\fR" 4
-.IX Item "file.h"
-C header file (not to be compiled or linked).
-.Ip "\fIfile\fR\fB.cc\fR" 4
-.IX Item "file.cc"
-.PD 0
-.Ip "\fIfile\fR\fB.cp\fR" 4
-.IX Item "file.cp"
-.Ip "\fIfile\fR\fB.cxx\fR" 4
-.IX Item "file.cxx"
-.Ip "\fIfile\fR\fB.cpp\fR" 4
-.IX Item "file.cpp"
-.Ip "\fIfile\fR\fB.c++\fR" 4
-.IX Item "file.c++"
-.Ip "\fIfile\fR\fB.C\fR" 4
-.IX Item "file.C"
-.PD
-\&\*(C+ source code which must be preprocessed. Note that in \fB.cxx\fR,
-the last two letters must both be literally \fBx\fR. Likewise,
-\&\fB.C\fR refers to a literal capital C.
-.Ip "\fIfile\fR\fB.f\fR" 4
-.IX Item "file.f"
-.PD 0
-.Ip "\fIfile\fR\fB.for\fR" 4
-.IX Item "file.for"
-.Ip "\fIfile\fR\fB.FOR\fR" 4
-.IX Item "file.FOR"
-.PD
-Fortran source code which should not be preprocessed.
-.Ip "\fIfile\fR\fB.F\fR" 4
-.IX Item "file.F"
-.PD 0
-.Ip "\fIfile\fR\fB.fpp\fR" 4
-.IX Item "file.fpp"
-.Ip "\fIfile\fR\fB.FPP\fR" 4
-.IX Item "file.FPP"
-.PD
-Fortran source code which must be preprocessed (with the traditional
-preprocessor).
-.Ip "\fIfile\fR\fB.r\fR" 4
-.IX Item "file.r"
-Fortran source code which must be preprocessed with a \s-1RATFOR\s0
-preprocessor (not included with \s-1GCC\s0).
-.Ip "\fIfile\fR\fB.ch\fR" 4
-.IX Item "file.ch"
-.PD 0
-.Ip "\fIfile\fR\fB.chi\fR" 4
-.IX Item "file.chi"
-.PD
-\&\s-1CHILL\s0 source code (preprocessed with the traditional preprocessor).
-.Ip "\fIfile\fR\fB.s\fR" 4
-.IX Item "file.s"
-Assembler code.
-.Ip "\fIfile\fR\fB.S\fR" 4
-.IX Item "file.S"
-Assembler code which must be preprocessed.
-.Ip "\fIother\fR" 4
-.IX Item "other"
-An object file to be fed straight into linking.
-Any file name with no recognized suffix is treated this way.
-.PP
-You can specify the input language explicitly with the \fB\-x\fR option:
-.Ip "\fB\-x\fR \fIlanguage\fR" 4
-.IX Item "-x language"
-Specify explicitly the \fIlanguage\fR for the following input files
-(rather than letting the compiler choose a default based on the file
-name suffix). This option applies to all following input files until
-the next \fB\-x\fR option. Possible values for \fIlanguage\fR are:
-.Sp
-.Vb 6
-\& c c-header cpp-output
-\& c++ c++-cpp-output
-\& objective-c objc-cpp-output
-\& assembler assembler-with-cpp
-\& f77 f77-cpp-input ratfor
-\& java chill
-.Ve
-.Ip "\fB\-x none\fR" 4
-.IX Item "-x none"
-Turn off any specification of a language, so that subsequent files are
-handled according to their file name suffixes (as they are if \fB\-x\fR
-has not been used at all).
-.Ip "\fB\-pass-exit-codes\fR" 4
-.IX Item "-pass-exit-codes"
-Normally the \fBgcc\fR program will exit with the code of 1 if any
-phase of the compiler returns a non-success return code. If you specify
-\&\fB\-pass-exit-codes\fR, the \fBgcc\fR program will instead return with
-numerically highest error produced by any phase that returned an error
-indication.
-.PP
-If you only want some of the stages of compilation, you can use
-\&\fB\-x\fR (or filename suffixes) to tell \fBgcc\fR where to start, and
-one of the options \fB\-c\fR, \fB\-S\fR, or \fB\-E\fR to say where
-\&\fBgcc\fR is to stop. Note that some combinations (for example,
-\&\fB\-x cpp-output \-E\fR) instruct \fBgcc\fR to do nothing at all.
-.Ip "\fB\-c\fR" 4
-.IX Item "-c"
-Compile or assemble the source files, but do not link. The linking
-stage simply is not done. The ultimate output is in the form of an
-object file for each source file.
-.Sp
-By default, the object file name for a source file is made by replacing
-the suffix \fB.c\fR, \fB.i\fR, \fB.s\fR, etc., with \fB.o\fR.
-.Sp
-Unrecognized input files, not requiring compilation or assembly, are
-ignored.
-.Ip "\fB\-S\fR" 4
-.IX Item "-S"
-Stop after the stage of compilation proper; do not assemble. The output
-is in the form of an assembler code file for each non-assembler input
-file specified.
-.Sp
-By default, the assembler file name for a source file is made by
-replacing the suffix \fB.c\fR, \fB.i\fR, etc., with \fB.s\fR.
-.Sp
-Input files that don't require compilation are ignored.
-.Ip "\fB\-E\fR" 4
-.IX Item "-E"
-Stop after the preprocessing stage; do not run the compiler proper. The
-output is in the form of preprocessed source code, which is sent to the
-standard output.
-.Sp
-Input files which don't require preprocessing are ignored.
-.Ip "\fB\-o\fR \fIfile\fR" 4
-.IX Item "-o file"
-Place output in file \fIfile\fR. This applies regardless to whatever
-sort of output is being produced, whether it be an executable file,
-an object file, an assembler file or preprocessed C code.
-.Sp
-Since only one output file can be specified, it does not make sense to
-use \fB\-o\fR when compiling more than one input file, unless you are
-producing an executable file as output.
-.Sp
-If \fB\-o\fR is not specified, the default is to put an executable file
-in \fIa.out\fR, the object file for \fI\fIsource\fI.\fIsuffix\fI\fR in
-\&\fI\fIsource\fI.o\fR, its assembler file in \fI\fIsource\fI.s\fR, and
-all preprocessed C source on standard output.
-.Ip "\fB\-v\fR" 4
-.IX Item "-v"
-Print (on standard error output) the commands executed to run the stages
-of compilation. Also print the version number of the compiler driver
-program and of the preprocessor and the compiler proper.
-.Ip "\fB\-pipe\fR" 4
-.IX Item "-pipe"
-Use pipes rather than temporary files for communication between the
-various stages of compilation. This fails to work on some systems where
-the assembler is unable to read from a pipe; but the \s-1GNU\s0 assembler has
-no trouble.
-.Ip "\fB\*(--help\fR" 4
-.IX Item "help"
-Print (on the standard output) a description of the command line options
-understood by \fBgcc\fR. If the \fB\-v\fR option is also specified
-then \fB\*(--help\fR will also be passed on to the various processes
-invoked by \fBgcc\fR, so that they can display the command line options
-they accept. If the \fB\-W\fR option is also specified then command
-line options which have no documentation associated with them will also
-be displayed.
-.Ip "\fB\*(--target-help\fR" 4
-.IX Item "target-help"
-Print (on the standard output) a description of target specific command
-line options for each tool.
-.Sh "Compiling \*(C+ Programs"
-.IX Subsection "Compiling Programs"
-\&\*(C+ source files conventionally use one of the suffixes \fB.C\fR,
-\&\fB.cc\fR, \fB.cpp\fR, \fB.c++\fR, \fB.cp\fR, or \fB.cxx\fR;
-preprocessed \*(C+ files use the suffix \fB.ii\fR. \s-1GCC\s0 recognizes
-files with these names and compiles them as \*(C+ programs even if you
-call the compiler the same way as for compiling C programs (usually with
-the name \fBgcc\fR).
-.PP
-However, \*(C+ programs often require class libraries as well as a
-compiler that understands the \*(C+ language\-\-\-and under some
-circumstances, you might want to compile programs from standard input,
-or otherwise without a suffix that flags them as \*(C+ programs.
-\&\fBg++\fR is a program that calls \s-1GCC\s0 with the default language
-set to \*(C+, and automatically specifies linking against the \*(C+
-library. On many systems, \fBg++\fR is also
-installed with the name \fBc++\fR.
-.PP
-When you compile \*(C+ programs, you may specify many of the same
-command-line options that you use for compiling programs in any
-language; or command-line options meaningful for C and related
-languages; or options that are meaningful only for \*(C+ programs.
-.Sh "Options Controlling C Dialect"
-.IX Subsection "Options Controlling C Dialect"
-The following options control the dialect of C (or languages derived
-from C, such as \*(C+ and Objective-C) that the compiler accepts:
-.Ip "\fB\-ansi\fR" 4
-.IX Item "-ansi"
-In C mode, support all \s-1ISO\s0 C89 programs. In \*(C+ mode,
-remove \s-1GNU\s0 extensions that conflict with \s-1ISO\s0 \*(C+.
-.Sp
-This turns off certain features of \s-1GCC\s0 that are incompatible with \s-1ISO\s0
-C (when compiling C code), or of standard \*(C+ (when compiling \*(C+ code),
-such as the \f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`typeof\*(C'\fR keywords, and
-predefined macros such as \f(CW\*(C`unix\*(C'\fR and \f(CW\*(C`vax\*(C'\fR that identify the
-type of system you are using. It also enables the undesirable and
-rarely used \s-1ISO\s0 trigraph feature. For the C compiler,
-it disables recognition of \*(C+ style \fB//\fR comments as well as
-the \f(CW\*(C`inline\*(C'\fR keyword.
-.Sp
-The alternate keywords \f(CW\*(C`_\|_asm_\|_\*(C'\fR, \f(CW\*(C`_\|_extension_\|_\*(C'\fR,
-\&\f(CW\*(C`_\|_inline_\|_\*(C'\fR and \f(CW\*(C`_\|_typeof_\|_\*(C'\fR continue to work despite
-\&\fB\-ansi\fR. You would not want to use them in an \s-1ISO\s0 C program, of
-course, but it is useful to put them in header files that might be included
-in compilations done with \fB\-ansi\fR. Alternate predefined macros
-such as \f(CW\*(C`_\|_unix_\|_\*(C'\fR and \f(CW\*(C`_\|_vax_\|_\*(C'\fR are also available, with or
-without \fB\-ansi\fR.
-.Sp
-The \fB\-ansi\fR option does not cause non-ISO programs to be
-rejected gratuitously. For that, \fB\-pedantic\fR is required in
-addition to \fB\-ansi\fR.
-.Sp
-The macro \f(CW\*(C`_\|_STRICT_ANSI_\|_\*(C'\fR is predefined when the \fB\-ansi\fR
-option is used. Some header files may notice this macro and refrain
-from declaring certain functions or defining certain macros that the
-\&\s-1ISO\s0 standard doesn't call for; this is to avoid interfering with any
-programs that might use these names for other things.
-.Sp
-Functions which would normally be built in but do not have semantics
-defined by \s-1ISO\s0 C (such as \f(CW\*(C`alloca\*(C'\fR and \f(CW\*(C`ffs\*(C'\fR) are not built-in
-functions with \fB\-ansi\fR is used.
-.Ip "\fB\-std=\fR" 4
-.IX Item "-std="
-Determine the language standard. A value for this option must be provided;
-possible values are
-.RS 4
-.Ip "\fBiso9899:1990\fR" 4
-.IX Item "iso9899:1990"
-Same as \fB\-ansi\fR
-.Ip "\fBiso9899:199409\fR" 4
-.IX Item "iso9899:199409"
-\&\s-1ISO\s0 C as modified in amend. 1
-.Ip "\fBiso9899:1999\fR" 4
-.IX Item "iso9899:1999"
-\&\s-1ISO\s0 C99. Note that this standard is not yet fully supported; see
-<\fBhttp://gcc.gnu.org/c99status.html\fR> for more information.
-.Ip "\fBc89\fR" 4
-.IX Item "c89"
-same as \fB\-std=iso9899:1990\fR
-.Ip "\fBc99\fR" 4
-.IX Item "c99"
-same as \fB\-std=iso9899:1999\fR
-.Ip "\fBgnu89\fR" 4
-.IX Item "gnu89"
-default, iso9899:1990 + gnu extensions
-.Ip "\fBgnu99\fR" 4
-.IX Item "gnu99"
-iso9899:1999 + gnu extensions
-.Ip "\fBiso9899:199x\fR" 4
-.IX Item "iso9899:199x"
-same as \fB\-std=iso9899:1999\fR, deprecated
-.Ip "\fBc9x\fR" 4
-.IX Item "c9x"
-same as \fB\-std=iso9899:1999\fR, deprecated
-.Ip "\fBgnu9x\fR" 4
-.IX Item "gnu9x"
-same as \fB\-std=gnu99\fR, deprecated
-.RE
-.RS 4
-.Sp
-Even when this option is not specified, you can still use some of the
-features of newer standards in so far as they do not conflict with
-previous C standards. For example, you may use \f(CW\*(C`_\|_restrict_\|_\*(C'\fR even
-when \fB\-std=c99\fR is not specified.
-.Sp
-The \fB\-std\fR options specifying some version of \s-1ISO\s0 C have the same
-effects as \fB\-ansi\fR, except that features that were not in \s-1ISO\s0 C89
-but are in the specified version (for example, \fB//\fR comments and
-the \f(CW\*(C`inline\*(C'\fR keyword in \s-1ISO\s0 C99) are not disabled.
-.RE
-.Ip "\fB\-aux-info\fR \fIfilename\fR" 4
-.IX Item "-aux-info filename"
-Output to the given filename prototyped declarations for all functions
-declared and/or defined in a translation unit, including those in header
-files. This option is silently ignored in any language other than C.
-.Sp
-Besides declarations, the file indicates, in comments, the origin of
-each declaration (source file and line), whether the declaration was
-implicit, prototyped or unprototyped (\fBI\fR, \fBN\fR for new or
-\&\fBO\fR for old, respectively, in the first character after the line
-number and the colon), and whether it came from a declaration or a
-definition (\fBC\fR or \fBF\fR, respectively, in the following
-character). In the case of function definitions, a K&R-style list of
-arguments followed by their declarations is also provided, inside
-comments, after the declaration.
-.Ip "\fB\-fno-asm\fR" 4
-.IX Item "-fno-asm"
-Do not recognize \f(CW\*(C`asm\*(C'\fR, \f(CW\*(C`inline\*(C'\fR or \f(CW\*(C`typeof\*(C'\fR as a
-keyword, so that code can use these words as identifiers. You can use
-the keywords \f(CW\*(C`_\|_asm_\|_\*(C'\fR, \f(CW\*(C`_\|_inline_\|_\*(C'\fR and \f(CW\*(C`_\|_typeof_\|_\*(C'\fR
-instead. \fB\-ansi\fR implies \fB\-fno-asm\fR.
-.Sp
-In \*(C+, this switch only affects the \f(CW\*(C`typeof\*(C'\fR keyword, since
-\&\f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`inline\*(C'\fR are standard keywords. You may want to
-use the \fB\-fno-gnu-keywords\fR flag instead, which has the same
-effect. In C99 mode (\fB\-std=c99\fR or \fB\-std=gnu99\fR), this
-switch only affects the \f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`typeof\*(C'\fR keywords, since
-\&\f(CW\*(C`inline\*(C'\fR is a standard keyword in \s-1ISO\s0 C99.
-.Ip "\fB\-fno-builtin\fR" 4
-.IX Item "-fno-builtin"
-Don't recognize built-in functions that do not begin with
-\&\fB_\|_builtin_\fR as prefix.
-.Sp
-\&\s-1GCC\s0 normally generates special code to handle certain built-in functions
-more efficiently; for instance, calls to \f(CW\*(C`alloca\*(C'\fR may become single
-instructions that adjust the stack directly, and calls to \f(CW\*(C`memcpy\*(C'\fR
-may become inline copy loops. The resulting code is often both smaller
-and faster, but since the function calls no longer appear as such, you
-cannot set a breakpoint on those calls, nor can you change the behavior
-of the functions by linking with a different library.
-.Sp
-In \*(C+, \fB\-fno-builtin\fR is always in effect. The \fB\-fbuiltin\fR
-option has no effect. Therefore, in \*(C+, the only way to get the
-optimization benefits of built-in functions is to call the function
-using the \fB_\|_builtin_\fR prefix. The \s-1GNU\s0 \*(C+ Standard Library uses
-built-in functions to implement many functions (like
-\&\f(CW\*(C`std::strchr\*(C'\fR), so that you automatically get efficient code.
-.Ip "\fB\-fhosted\fR" 4
-.IX Item "-fhosted"
-Assert that compilation takes place in a hosted environment. This implies
-\&\fB\-fbuiltin\fR. A hosted environment is one in which the
-entire standard library is available, and in which \f(CW\*(C`main\*(C'\fR has a return
-type of \f(CW\*(C`int\*(C'\fR. Examples are nearly everything except a kernel.
-This is equivalent to \fB\-fno-freestanding\fR.
-.Ip "\fB\-ffreestanding\fR" 4
-.IX Item "-ffreestanding"
-Assert that compilation takes place in a freestanding environment. This
-implies \fB\-fno-builtin\fR. A freestanding environment
-is one in which the standard library may not exist, and program startup may
-not necessarily be at \f(CW\*(C`main\*(C'\fR. The most obvious example is an \s-1OS\s0 kernel.
-This is equivalent to \fB\-fno-hosted\fR.
-.Ip "\fB\-trigraphs\fR" 4
-.IX Item "-trigraphs"
-Support \s-1ISO\s0 C trigraphs. The \fB\-ansi\fR option (and \fB\-std\fR
-options for strict \s-1ISO\s0 C conformance) implies \fB\-trigraphs\fR.
-.Ip "\fB\-traditional\fR" 4
-.IX Item "-traditional"
-Attempt to support some aspects of traditional C compilers.
-Specifically:
-.RS 4
-.Ip "\(bu" 4
-All \f(CW\*(C`extern\*(C'\fR declarations take effect globally even if they
-are written inside of a function definition. This includes implicit
-declarations of functions.
-.Ip "\(bu" 4
-The newer keywords \f(CW\*(C`typeof\*(C'\fR, \f(CW\*(C`inline\*(C'\fR, \f(CW\*(C`signed\*(C'\fR, \f(CW\*(C`const\*(C'\fR
-and \f(CW\*(C`volatile\*(C'\fR are not recognized. (You can still use the
-alternative keywords such as \f(CW\*(C`_\|_typeof_\|_\*(C'\fR, \f(CW\*(C`_\|_inline_\|_\*(C'\fR, and
-so on.)
-.Ip "\(bu" 4
-Comparisons between pointers and integers are always allowed.
-.Ip "\(bu" 4
-Integer types \f(CW\*(C`unsigned short\*(C'\fR and \f(CW\*(C`unsigned char\*(C'\fR promote
-to \f(CW\*(C`unsigned int\*(C'\fR.
-.Ip "\(bu" 4
-Out-of-range floating point literals are not an error.
-.Ip "\(bu" 4
-Certain constructs which \s-1ISO\s0 regards as a single invalid preprocessing
-number, such as \fB0xe-0xd\fR, are treated as expressions instead.
-.Ip "\(bu" 4
-String ``constants'' are not necessarily constant; they are stored in
-writable space, and identical looking constants are allocated
-separately. (This is the same as the effect of
-\&\fB\-fwritable-strings\fR.)
-.Ip "\(bu" 4
-All automatic variables not declared \f(CW\*(C`register\*(C'\fR are preserved by
-\&\f(CW\*(C`longjmp\*(C'\fR. Ordinarily, \s-1GNU\s0 C follows \s-1ISO\s0 C: automatic variables
-not declared \f(CW\*(C`volatile\*(C'\fR may be clobbered.
-.Ip "\(bu" 4
-The character escape sequences \fB\ex\fR and \fB\ea\fR evaluate as the
-literal characters \fBx\fR and \fBa\fR respectively. Without
-\&\fB\-traditional\fR, \fB\ex\fR is a prefix for the hexadecimal
-representation of a character, and \fB\ea\fR produces a bell.
-.RE
-.RS 4
-.Sp
-You may wish to use \fB\-fno-builtin\fR as well as \fB\-traditional\fR
-if your program uses names that are normally \s-1GNU\s0 C built-in functions for
-other purposes of its own.
-.Sp
-You cannot use \fB\-traditional\fR if you include any header files that
-rely on \s-1ISO\s0 C features. Some vendors are starting to ship systems with
-\&\s-1ISO\s0 C header files and you cannot use \fB\-traditional\fR on such
-systems to compile files that include any system headers.
-.Sp
-The \fB\-traditional\fR option also enables \fB\-traditional-cpp\fR,
-which is described next.
-.RE
-.Ip "\fB\-traditional-cpp\fR" 4
-.IX Item "-traditional-cpp"
-Attempt to support some aspects of traditional C preprocessors.
-Specifically:
-.RS 4
-.Ip "\(bu" 4
-Comments convert to nothing at all, rather than to a space. This allows
-traditional token concatenation.
-.Ip "\(bu" 4
-In a preprocessing directive, the \fB#\fR symbol must appear as the first
-character of a line.
-.Ip "\(bu" 4
-Macro arguments are recognized within string constants in a macro
-definition (and their values are stringified, though without additional
-quote marks, when they appear in such a context). The preprocessor
-always considers a string constant to end at a newline.
-.Ip "\(bu" 4
-The predefined macro \f(CW\*(C`_\|_STDC_\|_\*(C'\fR is not defined when you use
-\&\fB\-traditional\fR, but \f(CW\*(C`_\|_GNUC_\|_\*(C'\fR is (since the \s-1GNU\s0 extensions
-which \f(CW\*(C`_\|_GNUC_\|_\*(C'\fR indicates are not affected by
-\&\fB\-traditional\fR). If you need to write header files that work
-differently depending on whether \fB\-traditional\fR is in use, by
-testing both of these predefined macros you can distinguish four
-situations: \s-1GNU\s0 C, traditional \s-1GNU\s0 C, other \s-1ISO\s0 C compilers, and other
-old C compilers. The predefined macro \f(CW\*(C`_\|_STDC_VERSION_\|_\*(C'\fR is also
-not defined when you use \fB\-traditional\fR.
-.Ip "\(bu" 4
-The preprocessor considers a string constant to end at a newline (unless
-the newline is escaped with \fB\e\fR). (Without \fB\-traditional\fR,
-string constants can contain the newline character as typed.)
-.RE
-.RS 4
-.RE
-.Ip "\fB\-fcond-mismatch\fR" 4
-.IX Item "-fcond-mismatch"
-Allow conditional expressions with mismatched types in the second and
-third arguments. The value of such an expression is void. This option
-is not supported for \*(C+.
-.Ip "\fB\-funsigned-char\fR" 4
-.IX Item "-funsigned-char"
-Let the type \f(CW\*(C`char\*(C'\fR be unsigned, like \f(CW\*(C`unsigned char\*(C'\fR.
-.Sp
-Each kind of machine has a default for what \f(CW\*(C`char\*(C'\fR should
-be. It is either like \f(CW\*(C`unsigned char\*(C'\fR by default or like
-\&\f(CW\*(C`signed char\*(C'\fR by default.
-.Sp
-Ideally, a portable program should always use \f(CW\*(C`signed char\*(C'\fR or
-\&\f(CW\*(C`unsigned char\*(C'\fR when it depends on the signedness of an object.
-But many programs have been written to use plain \f(CW\*(C`char\*(C'\fR and
-expect it to be signed, or expect it to be unsigned, depending on the
-machines they were written for. This option, and its inverse, let you
-make such a program work with the opposite default.
-.Sp
-The type \f(CW\*(C`char\*(C'\fR is always a distinct type from each of
-\&\f(CW\*(C`signed char\*(C'\fR or \f(CW\*(C`unsigned char\*(C'\fR, even though its behavior
-is always just like one of those two.
-.Ip "\fB\-fsigned-char\fR" 4
-.IX Item "-fsigned-char"
-Let the type \f(CW\*(C`char\*(C'\fR be signed, like \f(CW\*(C`signed char\*(C'\fR.
-.Sp
-Note that this is equivalent to \fB\-fno-unsigned-char\fR, which is
-the negative form of \fB\-funsigned-char\fR. Likewise, the option
-\&\fB\-fno-signed-char\fR is equivalent to \fB\-funsigned-char\fR.
-.Ip "\fB\-fsigned-bitfields\fR" 4
-.IX Item "-fsigned-bitfields"
-.PD 0
-.Ip "\fB\-funsigned-bitfields\fR" 4
-.IX Item "-funsigned-bitfields"
-.Ip "\fB\-fno-signed-bitfields\fR" 4
-.IX Item "-fno-signed-bitfields"
-.Ip "\fB\-fno-unsigned-bitfields\fR" 4
-.IX Item "-fno-unsigned-bitfields"
-.PD
-These options control whether a bit-field is signed or unsigned, when the
-declaration does not use either \f(CW\*(C`signed\*(C'\fR or \f(CW\*(C`unsigned\*(C'\fR. By
-default, such a bit-field is signed, because this is consistent: the
-basic integer types such as \f(CW\*(C`int\*(C'\fR are signed types.
-.Sp
-However, when \fB\-traditional\fR is used, bit-fields are all unsigned
-no matter what.
-.Ip "\fB\-fwritable-strings\fR" 4
-.IX Item "-fwritable-strings"
-Store string constants in the writable data segment and don't uniquize
-them. This is for compatibility with old programs which assume they can
-write into string constants. The option \fB\-traditional\fR also has
-this effect.
-.Sp
-Writing into string constants is a very bad idea; ``constants'' should
-be constant.
-.Ip "\fB\-fallow-single-precision\fR" 4
-.IX Item "-fallow-single-precision"
-Do not promote single precision math operations to double precision,
-even when compiling with \fB\-traditional\fR.
-.Sp
-Traditional K&R C promotes all floating point operations to double
-precision, regardless of the sizes of the operands. On the
-architecture for which you are compiling, single precision may be faster
-than double precision. If you must use \fB\-traditional\fR, but want
-to use single precision operations when the operands are single
-precision, use this option. This option has no effect when compiling
-with \s-1ISO\s0 or \s-1GNU\s0 C conventions (the default).
-.Ip "\fB\-fshort-wchar\fR" 4
-.IX Item "-fshort-wchar"
-Override the underlying type for \fBwchar_t\fR to be \fBshort
-unsigned int\fR instead of the default for the target. This option is
-useful for building programs to run under \s-1WINE\s0.
-.Sh "Options Controlling \*(C+ Dialect"
-.IX Subsection "Options Controlling Dialect"
-This section describes the command-line options that are only meaningful
-for \*(C+ programs; but you can also use most of the \s-1GNU\s0 compiler options
-regardless of what language your program is in. For example, you
-might compile a file \f(CW\*(C`firstClass.C\*(C'\fR like this:
-.PP
-.Vb 1
-\& g++ -g -frepo -O -c firstClass.C
-.Ve
-In this example, only \fB\-frepo\fR is an option meant
-only for \*(C+ programs; you can use the other options with any
-language supported by \s-1GCC\s0.
-.PP
-Here is a list of options that are \fIonly\fR for compiling \*(C+ programs:
-.Ip "\fB\-fno-access-control\fR" 4
-.IX Item "-fno-access-control"
-Turn off all access checking. This switch is mainly useful for working
-around bugs in the access control code.
-.Ip "\fB\-fcheck-new\fR" 4
-.IX Item "-fcheck-new"
-Check that the pointer returned by \f(CW\*(C`operator new\*(C'\fR is non-null
-before attempting to modify the storage allocated. The current Working
-Paper requires that \f(CW\*(C`operator new\*(C'\fR never return a null pointer, so
-this check is normally unnecessary.
-.Sp
-An alternative to using this option is to specify that your
-\&\f(CW\*(C`operator new\*(C'\fR does not throw any exceptions; if you declare it
-\&\fB\f(BIthrow()\fB\fR, g++ will check the return value. See also \fBnew
-(nothrow)\fR.
-.Ip "\fB\-fconserve-space\fR" 4
-.IX Item "-fconserve-space"
-Put uninitialized or runtime-initialized global variables into the
-common segment, as C does. This saves space in the executable at the
-cost of not diagnosing duplicate definitions. If you compile with this
-flag and your program mysteriously crashes after \f(CW\*(C`main()\*(C'\fR has
-completed, you may have an object that is being destroyed twice because
-two definitions were merged.
-.Sp
-This option is no longer useful on most targets, now that support has
-been added for putting variables into \s-1BSS\s0 without making them common.
-.Ip "\fB\-fno-const-strings\fR" 4
-.IX Item "-fno-const-strings"
-Give string constants type \f(CW\*(C`char *\*(C'\fR instead of type \f(CW\*(C`const
-char *\*(C'\fR. By default, G++ uses type \f(CW\*(C`const char *\*(C'\fR as required by
-the standard. Even if you use \fB\-fno-const-strings\fR, you cannot
-actually modify the value of a string constant, unless you also use
-\&\fB\-fwritable-strings\fR.
-.Sp
-This option might be removed in a future release of G++. For maximum
-portability, you should structure your code so that it works with
-string constants that have type \f(CW\*(C`const char *\*(C'\fR.
-.Ip "\fB\-fdollars-in-identifiers\fR" 4
-.IX Item "-fdollars-in-identifiers"
-Accept \fB$\fR in identifiers. You can also explicitly prohibit use of
-\&\fB$\fR with the option \fB\-fno-dollars-in-identifiers\fR. (\s-1GNU\s0 C allows
-\&\fB$\fR by default on most target systems, but there are a few exceptions.)
-Traditional C allowed the character \fB$\fR to form part of
-identifiers. However, \s-1ISO\s0 C and \*(C+ forbid \fB$\fR in identifiers.
-.Ip "\fB\-fno-elide-constructors\fR" 4
-.IX Item "-fno-elide-constructors"
-The \*(C+ standard allows an implementation to omit creating a temporary
-which is only used to initialize another object of the same type.
-Specifying this option disables that optimization, and forces g++ to
-call the copy constructor in all cases.
-.Ip "\fB\-fno-enforce-eh-specs\fR" 4
-.IX Item "-fno-enforce-eh-specs"
-Don't check for violation of exception specifications at runtime. This
-option violates the \*(C+ standard, but may be useful for reducing code
-size in production builds, much like defining \fB\s-1NDEBUG\s0\fR. The compiler
-will still optimize based on the exception specifications.
-.Ip "\fB\-fexternal-templates\fR" 4
-.IX Item "-fexternal-templates"
-Cause template instantiations to obey \fB#pragma interface\fR and
-\&\fBimplementation\fR; template instances are emitted or not according
-to the location of the template definition.
-.Sp
-This option is deprecated.
-.Ip "\fB\-falt-external-templates\fR" 4
-.IX Item "-falt-external-templates"
-Similar to \fB\-fexternal-templates\fR, but template instances are emitted or
-not according to the place where they are first instantiated.
-.Sp
-This option is deprecated.
-.Ip "\fB\-ffor-scope\fR" 4
-.IX Item "-ffor-scope"
-.PD 0
-.Ip "\fB\-fno-for-scope\fR" 4
-.IX Item "-fno-for-scope"
-.PD
-If \fB\-ffor-scope\fR is specified, the scope of variables declared in
-a \fIfor-init-statement\fR is limited to the \fBfor\fR loop itself,
-as specified by the \*(C+ standard.
-If \fB\-fno-for-scope\fR is specified, the scope of variables declared in
-a \fIfor-init-statement\fR extends to the end of the enclosing scope,
-as was the case in old versions of gcc, and other (traditional)
-implementations of \*(C+.
-.Sp
-The default if neither flag is given to follow the standard,
-but to allow and give a warning for old-style code that would
-otherwise be invalid, or have different behavior.
-.Ip "\fB\-fno-gnu-keywords\fR" 4
-.IX Item "-fno-gnu-keywords"
-Do not recognize \f(CW\*(C`typeof\*(C'\fR as a keyword, so that code can use this
-word as an identifier. You can use the keyword \f(CW\*(C`_\|_typeof_\|_\*(C'\fR instead.
-\&\fB\-ansi\fR implies \fB\-fno-gnu-keywords\fR.
-.Ip "\fB\-fno-honor-std\fR" 4
-.IX Item "-fno-honor-std"
-Ignore \f(CW\*(C`namespace std\*(C'\fR, instead of treating it as a real namespace.
-With this switch, the compiler will ignore
-\&\f(CW\*(C`namespace\-declarations\*(C'\fR, \f(CW\*(C`using\-declarations\*(C'\fR,
-\&\f(CW\*(C`using\-directives\*(C'\fR, and \f(CW\*(C`namespace\-names\*(C'\fR, if they involve
-\&\f(CW\*(C`std\*(C'\fR.
-.Sp
-This option is only useful if you have manually compiled the \*(C+
-run-time library with the same switch. Otherwise, your programs will
-not link. The use of this option is not recommended, and the option may
-be removed from a future version of G++.
-.Ip "\fB\-fno-implicit-templates\fR" 4
-.IX Item "-fno-implicit-templates"
-Never emit code for non-inline templates which are instantiated
-implicitly (i.e. by use); only emit code for explicit instantiations.
-.Ip "\fB\-fno-implicit-inline-templates\fR" 4
-.IX Item "-fno-implicit-inline-templates"
-Don't emit code for implicit instantiations of inline templates, either.
-The default is to handle inlines differently so that compiles with and
-without optimization will need the same set of explicit instantiations.
-.Ip "\fB\-fno-implement-inlines\fR" 4
-.IX Item "-fno-implement-inlines"
-To save space, do not emit out-of-line copies of inline functions
-controlled by \fB#pragma implementation\fR. This will cause linker
-errors if these functions are not inlined everywhere they are called.
-.Ip "\fB\-fms-extensions\fR" 4
-.IX Item "-fms-extensions"
-Disable pedantic warnings about constructs used in \s-1MFC\s0, such as implicit
-int and getting a pointer to member function via non-standard syntax.
-.Ip "\fB\-fno-nonansi-builtins\fR" 4
-.IX Item "-fno-nonansi-builtins"
-Disable built-in declarations of functions that are not mandated by
-\&\s-1ANSI/ISO\s0 C. These include \f(CW\*(C`ffs\*(C'\fR, \f(CW\*(C`alloca\*(C'\fR, \f(CW\*(C`_exit\*(C'\fR,
-\&\f(CW\*(C`index\*(C'\fR, \f(CW\*(C`bzero\*(C'\fR, \f(CW\*(C`conjf\*(C'\fR, and other related functions.
-.Ip "\fB\-fno-operator-names\fR" 4
-.IX Item "-fno-operator-names"
-Do not treat the operator name keywords \f(CW\*(C`and\*(C'\fR, \f(CW\*(C`bitand\*(C'\fR,
-\&\f(CW\*(C`bitor\*(C'\fR, \f(CW\*(C`compl\*(C'\fR, \f(CW\*(C`not\*(C'\fR, \f(CW\*(C`or\*(C'\fR and \f(CW\*(C`xor\*(C'\fR as
-synonyms as keywords.
-.Ip "\fB\-fno-optional-diags\fR" 4
-.IX Item "-fno-optional-diags"
-Disable diagnostics that the standard says a compiler does not need to
-issue. Currently, the only such diagnostic issued by g++ is the one for
-a name having multiple meanings within a class.
-.Ip "\fB\-fpermissive\fR" 4
-.IX Item "-fpermissive"
-Downgrade messages about nonconformant code from errors to warnings. By
-default, g++ effectively sets \fB\-pedantic-errors\fR without
-\&\fB\-pedantic\fR; this option reverses that. This behavior and this
-option are superseded by \fB\-pedantic\fR, which works as it does for \s-1GNU\s0 C.
-.Ip "\fB\-frepo\fR" 4
-.IX Item "-frepo"
-Enable automatic template instantiation. This option also implies
-\&\fB\-fno-implicit-templates\fR.
-.Ip "\fB\-fno-rtti\fR" 4
-.IX Item "-fno-rtti"
-Disable generation of information about every class with virtual
-functions for use by the \*(C+ runtime type identification features
-(\fBdynamic_cast\fR and \fBtypeid\fR). If you don't use those parts
-of the language, you can save some space by using this flag. Note that
-exception handling uses the same information, but it will generate it as
-needed.
-.Ip "\fB\-fstats\fR" 4
-.IX Item "-fstats"
-Emit statistics about front-end processing at the end of the compilation.
-This information is generally only useful to the G++ development team.
-.Ip "\fB\-ftemplate-depth-\fR\fIn\fR" 4
-.IX Item "-ftemplate-depth-n"
-Set the maximum instantiation depth for template classes to \fIn\fR.
-A limit on the template instantiation depth is needed to detect
-endless recursions during template class instantiation. \s-1ANSI/ISO\s0 \*(C+
-conforming programs must not rely on a maximum depth greater than 17.
-.Ip "\fB\-fuse-cxa-atexit\fR" 4
-.IX Item "-fuse-cxa-atexit"
-Register destructors for objects with static storage duration with the
-\&\f(CW\*(C`_\|_cxa_atexit\*(C'\fR function rather than the \f(CW\*(C`atexit\*(C'\fR function.
-This option is required for fully standards-compliant handling of static
-destructors, but will only work if your C library supports
-\&\f(CW\*(C`_\|_cxa_atexit\*(C'\fR.
-.Ip "\fB\-fvtable-gc\fR" 4
-.IX Item "-fvtable-gc"
-Emit special relocations for vtables and virtual function references
-so that the linker can identify unused virtual functions and zero out
-vtable slots that refer to them. This is most useful with
-\&\fB\-ffunction-sections\fR and \fB\-Wl,\-\-gc-sections\fR, in order to
-also discard the functions themselves.
-.Sp
-This optimization requires \s-1GNU\s0 as and \s-1GNU\s0 ld. Not all systems support
-this option. \fB\-Wl,\-\-gc-sections\fR is ignored without \fB\-static\fR.
-.Ip "\fB\-fno-weak\fR" 4
-.IX Item "-fno-weak"
-Do not use weak symbol support, even if it is provided by the linker.
-By default, G++ will use weak symbols if they are available. This
-option exists only for testing, and should not be used by end-users;
-it will result in inferior code and has no benefits. This option may
-be removed in a future release of G++.
-.Ip "\fB\-nostdinc++\fR" 4
-.IX Item "-nostdinc++"
-Do not search for header files in the standard directories specific to
-\&\*(C+, but do still search the other standard directories. (This option
-is used when building the \*(C+ library.)
-.PP
-In addition, these optimization, warning, and code generation options
-have meanings only for \*(C+ programs:
-.Ip "\fB\-fno-default-inline\fR" 4
-.IX Item "-fno-default-inline"
-Do not assume \fBinline\fR for functions defined inside a class scope.
- Note that these
-functions will have linkage like inline functions; they just won't be
-inlined by default.
-.Ip "\fB\-Wctor-dtor-privacy (\*(C+ only)\fR" 4
-.IX Item "-Wctor-dtor-privacy ( only)"
-Warn when a class seems unusable, because all the constructors or
-destructors in a class are private and the class has no friends or
-public static member functions.
-.Ip "\fB\-Wnon-virtual-dtor (\*(C+ only)\fR" 4
-.IX Item "-Wnon-virtual-dtor ( only)"
-Warn when a class declares a non-virtual destructor that should probably
-be virtual, because it looks like the class will be used polymorphically.
-.Ip "\fB\-Wreorder (\*(C+ only)\fR" 4
-.IX Item "-Wreorder ( only)"
-Warn when the order of member initializers given in the code does not
-match the order in which they must be executed. For instance:
-.Sp
-.Vb 5
-\& struct A {
-\& int i;
-\& int j;
-\& A(): j (0), i (1) { }
-\& };
-.Ve
-Here the compiler will warn that the member initializers for \fBi\fR
-and \fBj\fR will be rearranged to match the declaration order of the
-members.
-.PP
-The following \fB\-W...\fR options are not affected by \fB\-Wall\fR.
-.Ip "\fB\-Weffc++ (\*(C+ only)\fR" 4
-.IX Item "-Weffc++ ( only)"
-Warn about violations of various style guidelines from Scott Meyers'
-\&\fIEffective \*(C+\fR books. If you use this option, you should be aware
-that the standard library headers do not obey all of these guidelines;
-you can use \fBgrep \-v\fR to filter out those warnings.
-.Ip "\fB\-Wno-deprecated (\*(C+ only)\fR" 4
-.IX Item "-Wno-deprecated ( only)"
-Do not warn about usage of deprecated features.
-.Ip "\fB\-Wno-non-template-friend (\*(C+ only)\fR" 4
-.IX Item "-Wno-non-template-friend ( only)"
-Disable warnings when non-templatized friend functions are declared
-within a template. With the advent of explicit template specification
-support in g++, if the name of the friend is an unqualified-id (i.e.,
-\&\fBfriend foo(int)\fR), the \*(C+ language specification demands that the
-friend declare or define an ordinary, nontemplate function. (Section
-14.5.3). Before g++ implemented explicit specification, unqualified-ids
-could be interpreted as a particular specialization of a templatized
-function. Because this non-conforming behavior is no longer the default
-behavior for g++, \fB\-Wnon-template-friend\fR allows the compiler to
-check existing code for potential trouble spots, and is on by default.
-This new compiler behavior can be turned off with
-\&\fB\-Wno-non-template-friend\fR which keeps the conformant compiler code
-but disables the helpful warning.
-.Ip "\fB\-Wold-style-cast (\*(C+ only)\fR" 4
-.IX Item "-Wold-style-cast ( only)"
-Warn if an old-style (C-style) cast is used within a \*(C+ program. The
-new-style casts (\fBstatic_cast\fR, \fBreinterpret_cast\fR, and
-\&\fBconst_cast\fR) are less vulnerable to unintended effects, and much
-easier to grep for.
-.Ip "\fB\-Woverloaded-virtual (\*(C+ only)\fR" 4
-.IX Item "-Woverloaded-virtual ( only)"
-Warn when a function declaration hides virtual functions from a
-base class. For example, in:
-.Sp
-.Vb 3
-\& struct A {
-\& virtual void f();
-\& };
-.Ve
-.Vb 3
-\& struct B: public A {
-\& void f(int);
-\& };
-.Ve
-the \f(CW\*(C`A\*(C'\fR class version of \f(CW\*(C`f\*(C'\fR is hidden in \f(CW\*(C`B\*(C'\fR, and code
-like this:
-.Sp
-.Vb 2
-\& B* b;
-\& b->f();
-.Ve
-will fail to compile.
-.Ip "\fB\-Wno-pmf-conversions (\*(C+ only)\fR" 4
-.IX Item "-Wno-pmf-conversions ( only)"
-Disable the diagnostic for converting a bound pointer to member function
-to a plain pointer.
-.Ip "\fB\-Wsign-promo (\*(C+ only)\fR" 4
-.IX Item "-Wsign-promo ( only)"
-Warn when overload resolution chooses a promotion from unsigned or
-enumeral type to a signed type over a conversion to an unsigned type of
-the same size. Previous versions of g++ would try to preserve
-unsignedness, but the standard mandates the current behavior.
-.Ip "\fB\-Wsynth (\*(C+ only)\fR" 4
-.IX Item "-Wsynth ( only)"
-Warn when g++'s synthesis behavior does not match that of cfront. For
-instance:
-.Sp
-.Vb 4
-\& struct A {
-\& operator int ();
-\& A& operator = (int);
-\& };
-.Ve
-.Vb 5
-\& main ()
-\& {
-\& A a,b;
-\& a = b;
-\& }
-.Ve
-In this example, g++ will synthesize a default \fBA& operator =
-(const A&);\fR, while cfront will use the user-defined \fBoperator =\fR.
-.Sh "Options Controlling Objective-C Dialect"
-.IX Subsection "Options Controlling Objective-C Dialect"
-This section describes the command-line options that are only meaningful
-for Objective-C programs; but you can also use most of the \s-1GNU\s0 compiler
-options regardless of what language your program is in. For example,
-you might compile a file \f(CW\*(C`some_class.m\*(C'\fR like this:
-.PP
-.Vb 1
-\& gcc -g -fgnu-runtime -O -c some_class.m
-.Ve
-In this example, only \fB\-fgnu-runtime\fR is an option meant only for
-Objective-C programs; you can use the other options with any language
-supported by \s-1GCC\s0.
-.PP
-Here is a list of options that are \fIonly\fR for compiling Objective-C
-programs:
-.Ip "\fB\-fconstant-string-class=\fR\fIclass-name\fR" 4
-.IX Item "-fconstant-string-class=class-name"
-Use \fIclass-name\fR as the name of the class to instantiate for each
-literal string specified with the syntax \f(CW\*(C`@"..."\*(C'\fR. The default
-class name is \f(CW\*(C`NXConstantString\*(C'\fR.
-.Ip "\fB\-fgnu-runtime\fR" 4
-.IX Item "-fgnu-runtime"
-Generate object code compatible with the standard \s-1GNU\s0 Objective-C
-runtime. This is the default for most types of systems.
-.Ip "\fB\-fnext-runtime\fR" 4
-.IX Item "-fnext-runtime"
-Generate output compatible with the NeXT runtime. This is the default
-for NeXT-based systems, including Darwin and Mac \s-1OS\s0 X.
-.Ip "\fB\-gen-decls\fR" 4
-.IX Item "-gen-decls"
-Dump interface declarations for all classes seen in the source file to a
-file named \fI\fIsourcename\fI.decl\fR.
-.Ip "\fB\-Wno-protocol\fR" 4
-.IX Item "-Wno-protocol"
-Do not warn if methods required by a protocol are not implemented
-in the class adopting it.
-.Ip "\fB\-Wselector\fR" 4
-.IX Item "-Wselector"
-Warn if a selector has multiple methods of different types defined.
-.Sh "Options to Control Diagnostic Messages Formatting"
-.IX Subsection "Options to Control Diagnostic Messages Formatting"
-Traditionally, diagnostic messages have been formatted irrespective of
-the output device's aspect (e.g. its width, ...). The options described
-below can be used to control the diagnostic messages formatting
-algorithm, e.g. how many characters per line, how often source location
-information should be reported. Right now, only the \*(C+ front end can
-honor these options. However it is expected, in the near future, that
-the remaining front ends would be able to digest them correctly.
-.Ip "\fB\-fmessage-length=\fR\fIn\fR" 4
-.IX Item "-fmessage-length=n"
-Try to format error messages so that they fit on lines of about \fIn\fR
-characters. The default is 72 characters for g++ and 0 for the rest of
-the front ends supported by \s-1GCC\s0. If \fIn\fR is zero, then no
-line-wrapping will be done; each error message will appear on a single
-line.
-.Ip "\fB\-fdiagnostics-show-location=once\fR" 4
-.IX Item "-fdiagnostics-show-location=once"
-Only meaningful in line-wrapping mode. Instructs the diagnostic messages
-reporter to emit \fIonce\fR source location information; that is, in
-case the message is too long to fit on a single physical line and has to
-be wrapped, the source location won't be emitted (as prefix) again,
-over and over, in subsequent continuation lines. This is the default
-behaviour.
-.Ip "\fB\-fdiagnostics-show-location=every-line\fR" 4
-.IX Item "-fdiagnostics-show-location=every-line"
-Only meaningful in line-wrapping mode. Instructs the diagnostic
-messages reporter to emit the same source location information (as
-prefix) for physical lines that result from the process of breaking a
-a message which is too long to fit on a single line.
-.Sh "Options to Request or Suppress Warnings"
-.IX Subsection "Options to Request or Suppress Warnings"
-Warnings are diagnostic messages that report constructions which
-are not inherently erroneous but which are risky or suggest there
-may have been an error.
-.PP
-You can request many specific warnings with options beginning \fB\-W\fR,
-for example \fB\-Wimplicit\fR to request warnings on implicit
-declarations. Each of these specific warning options also has a
-negative form beginning \fB\-Wno-\fR to turn off warnings;
-for example, \fB\-Wno-implicit\fR. This manual lists only one of the
-two forms, whichever is not the default.
-.PP
-These options control the amount and kinds of warnings produced by \s-1GCC:\s0
-.Ip "\fB\-fsyntax-only\fR" 4
-.IX Item "-fsyntax-only"
-Check the code for syntax errors, but don't do anything beyond that.
-.Ip "\fB\-pedantic\fR" 4
-.IX Item "-pedantic"
-Issue all the warnings demanded by strict \s-1ISO\s0 C and \s-1ISO\s0 \*(C+;
-reject all programs that use forbidden extensions, and some other
-programs that do not follow \s-1ISO\s0 C and \s-1ISO\s0 \*(C+. For \s-1ISO\s0 C, follows the
-version of the \s-1ISO\s0 C standard specified by any \fB\-std\fR option used.
-.Sp
-Valid \s-1ISO\s0 C and \s-1ISO\s0 \*(C+ programs should compile properly with or without
-this option (though a rare few will require \fB\-ansi\fR or a
-\&\fB\-std\fR option specifying the required version of \s-1ISO\s0 C). However,
-without this option, certain \s-1GNU\s0 extensions and traditional C and \*(C+
-features are supported as well. With this option, they are rejected.
-.Sp
-\&\fB\-pedantic\fR does not cause warning messages for use of the
-alternate keywords whose names begin and end with \fB_\|_\fR. Pedantic
-warnings are also disabled in the expression that follows
-\&\f(CW\*(C`_\|_extension_\|_\*(C'\fR. However, only system header files should use
-these escape routes; application programs should avoid them.
-.Sp
-Some users try to use \fB\-pedantic\fR to check programs for strict \s-1ISO\s0
-C conformance. They soon find that it does not do quite what they want:
-it finds some non-ISO practices, but not all\-\-\-only those for which
-\&\s-1ISO\s0 C \fIrequires\fR a diagnostic, and some others for which
-diagnostics have been added.
-.Sp
-A feature to report any failure to conform to \s-1ISO\s0 C might be useful in
-some instances, but would require considerable additional work and would
-be quite different from \fB\-pedantic\fR. We don't have plans to
-support such a feature in the near future.
-.Sp
-Where the standard specified with \fB\-std\fR represents a \s-1GNU\s0
-extended dialect of C, such as \fBgnu89\fR or \fBgnu99\fR, there is a
-corresponding \fIbase standard\fR, the version of \s-1ISO\s0 C on which the \s-1GNU\s0
-extended dialect is based. Warnings from \fB\-pedantic\fR are given
-where they are required by the base standard. (It would not make sense
-for such warnings to be given only for features not in the specified \s-1GNU\s0
-C dialect, since by definition the \s-1GNU\s0 dialects of C include all
-features the compiler supports with the given option, and there would be
-nothing to warn about.)
-.Ip "\fB\-pedantic-errors\fR" 4
-.IX Item "-pedantic-errors"
-Like \fB\-pedantic\fR, except that errors are produced rather than
-warnings.
-.Ip "\fB\-w\fR" 4
-.IX Item "-w"
-Inhibit all warning messages.
-.Ip "\fB\-Wno-import\fR" 4
-.IX Item "-Wno-import"
-Inhibit warning messages about the use of \fB#import\fR.
-.Ip "\fB\-Wchar-subscripts\fR" 4
-.IX Item "-Wchar-subscripts"
-Warn if an array subscript has type \f(CW\*(C`char\*(C'\fR. This is a common cause
-of error, as programmers often forget that this type is signed on some
-machines.
-.Ip "\fB\-Wcomment\fR" 4
-.IX Item "-Wcomment"
-Warn whenever a comment-start sequence \fB/*\fR appears in a \fB/*\fR
-comment, or whenever a Backslash-Newline appears in a \fB//\fR comment.
-.Ip "\fB\-Wformat\fR" 4
-.IX Item "-Wformat"
-Check calls to \f(CW\*(C`printf\*(C'\fR and \f(CW\*(C`scanf\*(C'\fR, etc., to make sure that
-the arguments supplied have types appropriate to the format string
-specified, and that the conversions specified in the format string make
-sense. This includes standard functions, and others specified by format
-attributes, in the \f(CW\*(C`printf\*(C'\fR,
-\&\f(CW\*(C`scanf\*(C'\fR, \f(CW\*(C`strftime\*(C'\fR and \f(CW\*(C`strfmon\*(C'\fR (an X/Open extension,
-not in the C standard) families.
-.Sp
-The formats are checked against the format features supported by \s-1GNU\s0
-libc version 2.2. These include all \s-1ISO\s0 C89 and C99 features, as well
-as features from the Single Unix Specification and some \s-1BSD\s0 and \s-1GNU\s0
-extensions. Other library implementations may not support all these
-features; \s-1GCC\s0 does not support warning about features that go beyond a
-particular library's limitations. However, if \fB\-pedantic\fR is used
-with \fB\-Wformat\fR, warnings will be given about format features not
-in the selected standard version (but not for \f(CW\*(C`strfmon\*(C'\fR formats,
-since those are not in any version of the C standard).
-.Sp
-\&\fB\-Wformat\fR is included in \fB\-Wall\fR. For more control over some
-aspects of format checking, the options \fB\-Wno-format-y2k\fR,
-\&\fB\-Wno-format-extra-args\fR, \fB\-Wformat-nonliteral\fR,
-\&\fB\-Wformat-security\fR and \fB\-Wformat=2\fR are available, but are
-not included in \fB\-Wall\fR.
-.Ip "\fB\-Wno-format-y2k\fR" 4
-.IX Item "-Wno-format-y2k"
-If \fB\-Wformat\fR is specified, do not warn about \f(CW\*(C`strftime\*(C'\fR
-formats which may yield only a two-digit year.
-.Ip "\fB\-Wno-format-extra-args\fR" 4
-.IX Item "-Wno-format-extra-args"
-If \fB\-Wformat\fR is specified, do not warn about excess arguments to a
-\&\f(CW\*(C`printf\*(C'\fR or \f(CW\*(C`scanf\*(C'\fR format function. The C standard specifies
-that such arguments are ignored.
-.Ip "\fB\-Wformat-nonliteral\fR" 4
-.IX Item "-Wformat-nonliteral"
-If \fB\-Wformat\fR is specified, also warn if the format string is not a
-string literal and so cannot be checked, unless the format function
-takes its format arguments as a \f(CW\*(C`va_list\*(C'\fR.
-.Ip "\fB\-Wformat-security\fR" 4
-.IX Item "-Wformat-security"
-If \fB\-Wformat\fR is specified, also warn about uses of format
-functions that represent possible security problems. At present, this
-warns about calls to \f(CW\*(C`printf\*(C'\fR and \f(CW\*(C`scanf\*(C'\fR functions where the
-format string is not a string literal and there are no format arguments,
-as in \f(CW\*(C`printf (foo);\*(C'\fR. This may be a security hole if the format
-string came from untrusted input and contains \fB%n\fR. (This is
-currently a subset of what \fB\-Wformat-nonliteral\fR warns about, but
-in future warnings may be added to \fB\-Wformat-security\fR that are not
-included in \fB\-Wformat-nonliteral\fR.)
-.Ip "\fB\-Wformat=2\fR" 4
-.IX Item "-Wformat=2"
-Enable \fB\-Wformat\fR plus format checks not included in
-\&\fB\-Wformat\fR. Currently equivalent to \fB\-Wformat
-\&\-Wformat-nonliteral \-Wformat-security\fR.
-.Ip "\fB\-Wimplicit-int\fR" 4
-.IX Item "-Wimplicit-int"
-Warn when a declaration does not specify a type.
-.Ip "\fB\-Wimplicit-function-declaration\fR" 4
-.IX Item "-Wimplicit-function-declaration"
-.PD 0
-.Ip "\fB\-Werror-implicit-function-declaration\fR" 4
-.IX Item "-Werror-implicit-function-declaration"
-.PD
-Give a warning (or error) whenever a function is used before being
-declared.
-.Ip "\fB\-Wimplicit\fR" 4
-.IX Item "-Wimplicit"
-Same as \fB\-Wimplicit-int\fR and \fB\-Wimplicit-function-declaration\fR.
-.Ip "\fB\-Wmain\fR" 4
-.IX Item "-Wmain"
-Warn if the type of \fBmain\fR is suspicious. \fBmain\fR should be a
-function with external linkage, returning int, taking either zero
-arguments, two, or three arguments of appropriate types.
-.Ip "\fB\-Wmissing-braces\fR" 4
-.IX Item "-Wmissing-braces"
-Warn if an aggregate or union initializer is not fully bracketed. In
-the following example, the initializer for \fBa\fR is not fully
-bracketed, but that for \fBb\fR is fully bracketed.
-.Sp
-.Vb 2
-\& int a[2][2] = { 0, 1, 2, 3 };
-\& int b[2][2] = { { 0, 1 }, { 2, 3 } };
-.Ve
-.Ip "\fB\-Wmultichar\fR" 4
-.IX Item "-Wmultichar"
-Warn if a multicharacter constant (\fB'\s-1FOOF\s0'\fR) is used. Usually they
-indicate a typo in the user's code, as they have implementation-defined
-values, and should not be used in portable code.
-.Ip "\fB\-Wparentheses\fR" 4
-.IX Item "-Wparentheses"
-Warn if parentheses are omitted in certain contexts, such
-as when there is an assignment in a context where a truth value
-is expected, or when operators are nested whose precedence people
-often get confused about.
-.Sp
-Also warn about constructions where there may be confusion to which
-\&\f(CW\*(C`if\*(C'\fR statement an \f(CW\*(C`else\*(C'\fR branch belongs. Here is an example of
-such a case:
-.Sp
-.Vb 7
-\& {
-\& if (a)
-\& if (b)
-\& foo ();
-\& else
-\& bar ();
-\& }
-.Ve
-In C, every \f(CW\*(C`else\*(C'\fR branch belongs to the innermost possible \f(CW\*(C`if\*(C'\fR
-statement, which in this example is \f(CW\*(C`if (b)\*(C'\fR. This is often not
-what the programmer expected, as illustrated in the above example by
-indentation the programmer chose. When there is the potential for this
-confusion, \s-1GCC\s0 will issue a warning when this flag is specified.
-To eliminate the warning, add explicit braces around the innermost
-\&\f(CW\*(C`if\*(C'\fR statement so there is no way the \f(CW\*(C`else\*(C'\fR could belong to
-the enclosing \f(CW\*(C`if\*(C'\fR. The resulting code would look like this:
-.Sp
-.Vb 9
-\& {
-\& if (a)
-\& {
-\& if (b)
-\& foo ();
-\& else
-\& bar ();
-\& }
-\& }
-.Ve
-.Ip "\fB\-Wsequence-point\fR" 4
-.IX Item "-Wsequence-point"
-Warn about code that may have undefined semantics because of violations
-of sequence point rules in the C standard.
-.Sp
-The C standard defines the order in which expressions in a C program are
-evaluated in terms of \fIsequence points\fR, which represent a partial
-ordering between the execution of parts of the program: those executed
-before the sequence point, and those executed after it. These occur
-after the evaluation of a full expression (one which is not part of a
-larger expression), after the evaluation of the first operand of a
-\&\f(CW\*(C`&&\*(C'\fR, \f(CW\*(C`||\*(C'\fR, \f(CW\*(C`? :\*(C'\fR or \f(CW\*(C`,\*(C'\fR (comma) operator, before a
-function is called (but after the evaluation of its arguments and the
-expression denoting the called function), and in certain other places.
-Other than as expressed by the sequence point rules, the order of
-evaluation of subexpressions of an expression is not specified. All
-these rules describe only a partial order rather than a total order,
-since, for example, if two functions are called within one expression
-with no sequence point between them, the order in which the functions
-are called is not specified. However, the standards committee have
-ruled that function calls do not overlap.
-.Sp
-It is not specified when between sequence points modifications to the
-values of objects take effect. Programs whose behavior depends on this
-have undefined behavior; the C standard specifies that ``Between the
-previous and next sequence point an object shall have its stored value
-modified at most once by the evaluation of an expression. Furthermore,
-the prior value shall be read only to determine the value to be
-stored.''. If a program breaks these rules, the results on any
-particular implementation are entirely unpredictable.
-.Sp
-Examples of code with undefined behavior are \f(CW\*(C`a = a++;\*(C'\fR, \f(CW\*(C`a[n]
-= b[n++]\*(C'\fR and \f(CW\*(C`a[i++] = i;\*(C'\fR. Some more complicated cases are not
-diagnosed by this option, and it may give an occasional false positive
-result, but in general it has been found fairly effective at detecting
-this sort of problem in programs.
-.Sp
-The present implementation of this option only works for C programs. A
-future implementation may also work for \*(C+ programs.
-.Sp
-There is some controversy over the precise meaning of the sequence point
-rules in subtle cases. Links to papers with alternative formal definitions
-and other related discussions may be found on our readings page
-<\fBhttp://gcc.gnu.org/readings.html\fR>.
-.Ip "\fB\-Wreturn-type\fR" 4
-.IX Item "-Wreturn-type"
-Warn whenever a function is defined with a return-type that defaults to
-\&\f(CW\*(C`int\*(C'\fR. Also warn about any \f(CW\*(C`return\*(C'\fR statement with no
-return-value in a function whose return-type is not \f(CW\*(C`void\*(C'\fR.
-.Sp
-For \*(C+, a function without return type always produces a diagnostic
-message, even when \fB\-Wno-return-type\fR is specified. The only
-exceptions are \fBmain\fR and functions defined in system headers.
-.Ip "\fB\-Wswitch\fR" 4
-.IX Item "-Wswitch"
-Warn whenever a \f(CW\*(C`switch\*(C'\fR statement has an index of enumeral type
-and lacks a \f(CW\*(C`case\*(C'\fR for one or more of the named codes of that
-enumeration. (The presence of a \f(CW\*(C`default\*(C'\fR label prevents this
-warning.) \f(CW\*(C`case\*(C'\fR labels outside the enumeration range also
-provoke warnings when this option is used.
-.Ip "\fB\-Wtrigraphs\fR" 4
-.IX Item "-Wtrigraphs"
-Warn if any trigraphs are encountered that might change the meaning of
-the program (trigraphs within comments are not warned about).
-.Ip "\fB\-Wunused-function\fR" 4
-.IX Item "-Wunused-function"
-Warn whenever a static function is declared but not defined or a
-non\e-inline static function is unused.
-.Ip "\fB\-Wunused-label\fR" 4
-.IX Item "-Wunused-label"
-Warn whenever a label is declared but not used.
-.Sp
-To suppress this warning use the \fBunused\fR attribute.
-.Ip "\fB\-Wunused-parameter\fR" 4
-.IX Item "-Wunused-parameter"
-Warn whenever a function parameter is unused aside from its declaration.
-.Sp
-To suppress this warning use the \fBunused\fR attribute.
-.Ip "\fB\-Wunused-variable\fR" 4
-.IX Item "-Wunused-variable"
-Warn whenever a local variable or non-constant static variable is unused
-aside from its declaration
-.Sp
-To suppress this warning use the \fBunused\fR attribute.
-.Ip "\fB\-Wunused-value\fR" 4
-.IX Item "-Wunused-value"
-Warn whenever a statement computes a result that is explicitly not used.
-.Sp
-To suppress this warning cast the expression to \fBvoid\fR.
-.Ip "\fB\-Wunused\fR" 4
-.IX Item "-Wunused"
-All all the above \fB\-Wunused\fR options combined.
-.Sp
-In order to get a warning about an unused function parameter, you must
-either specify \fB\-W \-Wunused\fR or separately specify
-\&\fB\-Wunused-parameter\fR.
-.Ip "\fB\-Wuninitialized\fR" 4
-.IX Item "-Wuninitialized"
-Warn if an automatic variable is used without first being initialized or
-if a variable may be clobbered by a \f(CW\*(C`setjmp\*(C'\fR call.
-.Sp
-These warnings are possible only in optimizing compilation,
-because they require data flow information that is computed only
-when optimizing. If you don't specify \fB\-O\fR, you simply won't
-get these warnings.
-.Sp
-These warnings occur only for variables that are candidates for
-register allocation. Therefore, they do not occur for a variable that
-is declared \f(CW\*(C`volatile\*(C'\fR, or whose address is taken, or whose size
-is other than 1, 2, 4 or 8 bytes. Also, they do not occur for
-structures, unions or arrays, even when they are in registers.
-.Sp
-Note that there may be no warning about a variable that is used only
-to compute a value that itself is never used, because such
-computations may be deleted by data flow analysis before the warnings
-are printed.
-.Sp
-These warnings are made optional because \s-1GCC\s0 is not smart
-enough to see all the reasons why the code might be correct
-despite appearing to have an error. Here is one example of how
-this can happen:
-.Sp
-.Vb 12
-\& {
-\& int x;
-\& switch (y)
-\& {
-\& case 1: x = 1;
-\& break;
-\& case 2: x = 4;
-\& break;
-\& case 3: x = 5;
-\& }
-\& foo (x);
-\& }
-.Ve
-If the value of \f(CW\*(C`y\*(C'\fR is always 1, 2 or 3, then \f(CW\*(C`x\*(C'\fR is
-always initialized, but \s-1GCC\s0 doesn't know this. Here is
-another common case:
-.Sp
-.Vb 6
-\& {
-\& int save_y;
-\& if (change_y) save_y = y, y = new_y;
-\& ...
-\& if (change_y) y = save_y;
-\& }
-.Ve
-This has no bug because \f(CW\*(C`save_y\*(C'\fR is used only if it is set.
-.Sp
-This option also warns when a non-volatile automatic variable might be
-changed by a call to \f(CW\*(C`longjmp\*(C'\fR. These warnings as well are possible
-only in optimizing compilation.
-.Sp
-The compiler sees only the calls to \f(CW\*(C`setjmp\*(C'\fR. It cannot know
-where \f(CW\*(C`longjmp\*(C'\fR will be called; in fact, a signal handler could
-call it at any point in the code. As a result, you may get a warning
-even when there is in fact no problem because \f(CW\*(C`longjmp\*(C'\fR cannot
-in fact be called at the place which would cause a problem.
-.Sp
-Some spurious warnings can be avoided if you declare all the functions
-you use that never return as \f(CW\*(C`noreturn\*(C'\fR.
-.Ip "\fB\-Wreorder (\*(C+ only)\fR" 4
-.IX Item "-Wreorder ( only)"
-Warn when the order of member initializers given in the code does not
-match the order in which they must be executed. For instance:
-.Ip "\fB\-Wunknown-pragmas\fR" 4
-.IX Item "-Wunknown-pragmas"
-Warn when a #pragma directive is encountered which is not understood by
-\&\s-1GCC\s0. If this command line option is used, warnings will even be issued
-for unknown pragmas in system header files. This is not the case if
-the warnings were only enabled by the \fB\-Wall\fR command line option.
-.Ip "\fB\-Wall\fR" 4
-.IX Item "-Wall"
-All of the above \fB\-W\fR options combined. This enables all the
-warnings about constructions that some users consider questionable, and
-that are easy to avoid (or modify to prevent the warning), even in
-conjunction with macros.
-.Ip "\fB\-Wsystem-headers\fR" 4
-.IX Item "-Wsystem-headers"
-Print warning messages for constructs found in system header files.
-Warnings from system headers are normally suppressed, on the assumption
-that they usually do not indicate real problems and would only make the
-compiler output harder to read. Using this command line option tells
-\&\s-1GCC\s0 to emit warnings from system headers as if they occurred in user
-code. However, note that using \fB\-Wall\fR in conjunction with this
-option will \fInot\fR warn about unknown pragmas in system
-headers\-\-\-for that, \fB\-Wunknown-pragmas\fR must also be used.
-.PP
-The following \fB\-W...\fR options are not implied by \fB\-Wall\fR.
-Some of them warn about constructions that users generally do not
-consider questionable, but which occasionally you might wish to check
-for; others warn about constructions that are necessary or hard to avoid
-in some cases, and there is no simple way to modify the code to suppress
-the warning.
-.Ip "\fB\-W\fR" 4
-.IX Item "-W"
-Print extra warning messages for these events:
-.RS 4
-.Ip "\(bu" 4
-A function can return either with or without a value. (Falling
-off the end of the function body is considered returning without
-a value.) For example, this function would evoke such a
-warning:
-.Sp
-.Vb 5
-\& foo (a)
-\& {
-\& if (a > 0)
-\& return a;
-\& }
-.Ve
-.Ip "\(bu" 4
-An expression-statement or the left-hand side of a comma expression
-contains no side effects.
-To suppress the warning, cast the unused expression to void.
-For example, an expression such as \fBx[i,j]\fR will cause a warning,
-but \fBx[(void)i,j]\fR will not.
-.Ip "\(bu" 4
-An unsigned value is compared against zero with \fB<\fR or \fB<=\fR.
-.Ip "\(bu" 4
-A comparison like \fBx<=y<=z\fR appears; this is equivalent to
-\&\fB(x<=y ? 1 : 0) <= z\fR, which is a different interpretation from
-that of ordinary mathematical notation.
-.Ip "\(bu" 4
-Storage-class specifiers like \f(CW\*(C`static\*(C'\fR are not the first things in
-a declaration. According to the C Standard, this usage is obsolescent.
-.Ip "\(bu" 4
-The return type of a function has a type qualifier such as \f(CW\*(C`const\*(C'\fR.
-Such a type qualifier has no effect, since the value returned by a
-function is not an lvalue. (But don't warn about the \s-1GNU\s0 extension of
-\&\f(CW\*(C`volatile void\*(C'\fR return types. That extension will be warned about
-if \fB\-pedantic\fR is specified.)
-.Ip "\(bu" 4
-If \fB\-Wall\fR or \fB\-Wunused\fR is also specified, warn about unused
-arguments.
-.Ip "\(bu" 4
-A comparison between signed and unsigned values could produce an
-incorrect result when the signed value is converted to unsigned.
-(But don't warn if \fB\-Wno-sign-compare\fR is also specified.)
-.Ip "\(bu" 4
-An aggregate has a partly bracketed initializer.
-For example, the following code would evoke such a warning,
-because braces are missing around the initializer for \f(CW\*(C`x.h\*(C'\fR:
-.Sp
-.Vb 3
-\& struct s { int f, g; };
-\& struct t { struct s h; int i; };
-\& struct t x = { 1, 2, 3 };
-.Ve
-.Ip "\(bu" 4
-An aggregate has an initializer which does not initialize all members.
-For example, the following code would cause such a warning, because
-\&\f(CW\*(C`x.h\*(C'\fR would be implicitly initialized to zero:
-.Sp
-.Vb 2
-\& struct s { int f, g, h; };
-\& struct s x = { 3, 4 };
-.Ve
-.RE
-.RS 4
-.RE
-.Ip "\fB\-Wfloat-equal\fR" 4
-.IX Item "-Wfloat-equal"
-Warn if floating point values are used in equality comparisons.
-.Sp
-The idea behind this is that sometimes it is convenient (for the
-programmer) to consider floating-point values as approximations to
-infinitely precise real numbers. If you are doing this, then you need
-to compute (by analysing the code, or in some other way) the maximum or
-likely maximum error that the computation introduces, and allow for it
-when performing comparisons (and when producing output, but that's a
-different problem). In particular, instead of testing for equality, you
-would check to see whether the two values have ranges that overlap; and
-this is done with the relational operators, so equality comparisons are
-probably mistaken.
-.Ip "\fB\-Wtraditional (C only)\fR" 4
-.IX Item "-Wtraditional (C only)"
-Warn about certain constructs that behave differently in traditional and
-\&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C
-equivalent, and/or problematic constructs which should be avoided.
-.RS 4
-.Ip "\(bu" 4
-Macro parameters that appear within string literals in the macro body.
-In traditional C macro replacement takes place within string literals,
-but does not in \s-1ISO\s0 C.
-.Ip "\(bu" 4
-In traditional C, some preprocessor directives did not exist.
-Traditional preprocessors would only consider a line to be a directive
-if the \fB#\fR appeared in column 1 on the line. Therefore
-\&\fB\-Wtraditional\fR warns about directives that traditional C
-understands but would ignore because the \fB#\fR does not appear as the
-first character on the line. It also suggests you hide directives like
-\&\fB#pragma\fR not understood by traditional C by indenting them. Some
-traditional implementations would not recognise \fB#elif\fR, so it
-suggests avoiding it altogether.
-.Ip "\(bu" 4
-A function-like macro that appears without arguments.
-.Ip "\(bu" 4
-The unary plus operator.
-.Ip "\(bu" 4
-The \fBU\fR integer constant suffix, or the \fBF\fR or \fBL\fR floating point
-constant suffixes. (Traditional C does support the \fBL\fR suffix on integer
-constants.) Note, these suffixes appear in macros defined in the system
-headers of most modern systems, e.g. the \fB_MIN\fR/\fB_MAX\fR macros in \f(CW\*(C`<limits.h>\*(C'\fR.
-Use of these macros in user code might normally lead to spurious
-warnings, however gcc's integrated preprocessor has enough context to
-avoid warning in these cases.
-.Ip "\(bu" 4
-A function declared external in one block and then used after the end of
-the block.
-.Ip "\(bu" 4
-A \f(CW\*(C`switch\*(C'\fR statement has an operand of type \f(CW\*(C`long\*(C'\fR.
-.Ip "\(bu" 4
-A non-\f(CW\*(C`static\*(C'\fR function declaration follows a \f(CW\*(C`static\*(C'\fR one.
-This construct is not accepted by some traditional C compilers.
-.Ip "\(bu" 4
-The \s-1ISO\s0 type of an integer constant has a different width or
-signedness from its traditional type. This warning is only issued if
-the base of the constant is ten. I.e. hexadecimal or octal values, which
-typically represent bit patterns, are not warned about.
-.Ip "\(bu" 4
-Usage of \s-1ISO\s0 string concatenation is detected.
-.Ip "\(bu" 4
-Initialization of automatic aggregates.
-.Ip "\(bu" 4
-Identifier conflicts with labels. Traditional C lacks a separate
-namespace for labels.
-.Ip "\(bu" 4
-Initialization of unions. If the initializer is zero, the warning is
-omitted. This is done under the assumption that the zero initializer in
-user code appears conditioned on e.g. \f(CW\*(C`_\|_STDC_\|_\*(C'\fR to avoid missing
-initializer warnings and relies on default initialization to zero in the
-traditional C case.
-.Ip "\(bu" 4
-Conversions by prototypes between fixed/floating point values and vice
-versa. The absence of these prototypes when compiling with traditional
-C would cause serious problems. This is a subset of the possible
-conversion warnings, for the full set use \fB\-Wconversion\fR.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-Wundef\fR" 4
-.IX Item "-Wundef"
-Warn if an undefined identifier is evaluated in an \fB#if\fR directive.
-.Ip "\fB\-Wshadow\fR" 4
-.IX Item "-Wshadow"
-Warn whenever a local variable shadows another local variable, parameter or
-global variable or whenever a built-in function is shadowed.
-.Ip "\fB\-Wlarger-than-\fR\fIlen\fR" 4
-.IX Item "-Wlarger-than-len"
-Warn whenever an object of larger than \fIlen\fR bytes is defined.
-.Ip "\fB\-Wpointer-arith\fR" 4
-.IX Item "-Wpointer-arith"
-Warn about anything that depends on the ``size of'' a function type or
-of \f(CW\*(C`void\*(C'\fR. \s-1GNU\s0 C assigns these types a size of 1, for
-convenience in calculations with \f(CW\*(C`void *\*(C'\fR pointers and pointers
-to functions.
-.Ip "\fB\-Wbad-function-cast (C only)\fR" 4
-.IX Item "-Wbad-function-cast (C only)"
-Warn whenever a function call is cast to a non-matching type.
-For example, warn if \f(CW\*(C`int malloc()\*(C'\fR is cast to \f(CW\*(C`anything *\*(C'\fR.
-.Ip "\fB\-Wcast-qual\fR" 4
-.IX Item "-Wcast-qual"
-Warn whenever a pointer is cast so as to remove a type qualifier from
-the target type. For example, warn if a \f(CW\*(C`const char *\*(C'\fR is cast
-to an ordinary \f(CW\*(C`char *\*(C'\fR.
-.Ip "\fB\-Wcast-align\fR" 4
-.IX Item "-Wcast-align"
-Warn whenever a pointer is cast such that the required alignment of the
-target is increased. For example, warn if a \f(CW\*(C`char *\*(C'\fR is cast to
-an \f(CW\*(C`int *\*(C'\fR on machines where integers can only be accessed at
-two- or four-byte boundaries.
-.Ip "\fB\-Wwrite-strings\fR" 4
-.IX Item "-Wwrite-strings"
-Give string constants the type \f(CW\*(C`const char[\f(CIlength\f(CW]\*(C'\fR so that
-copying the address of one into a non-\f(CW\*(C`const\*(C'\fR \f(CW\*(C`char *\*(C'\fR
-pointer will get a warning. These warnings will help you find at
-compile time code that can try to write into a string constant, but
-only if you have been very careful about using \f(CW\*(C`const\*(C'\fR in
-declarations and prototypes. Otherwise, it will just be a nuisance;
-this is why we did not make \fB\-Wall\fR request these warnings.
-.Ip "\fB\-Wconversion\fR" 4
-.IX Item "-Wconversion"
-Warn if a prototype causes a type conversion that is different from what
-would happen to the same argument in the absence of a prototype. This
-includes conversions of fixed point to floating and vice versa, and
-conversions changing the width or signedness of a fixed point argument
-except when the same as the default promotion.
-.Sp
-Also, warn if a negative integer constant expression is implicitly
-converted to an unsigned type. For example, warn about the assignment
-\&\f(CW\*(C`x = \-1\*(C'\fR if \f(CW\*(C`x\*(C'\fR is unsigned. But do not warn about explicit
-casts like \f(CW\*(C`(unsigned) \-1\*(C'\fR.
-.Ip "\fB\-Wsign-compare\fR" 4
-.IX Item "-Wsign-compare"
-Warn when a comparison between signed and unsigned values could produce
-an incorrect result when the signed value is converted to unsigned.
-This warning is also enabled by \fB\-W\fR; to get the other warnings
-of \fB\-W\fR without this warning, use \fB\-W \-Wno-sign-compare\fR.
-.Ip "\fB\-Waggregate-return\fR" 4
-.IX Item "-Waggregate-return"
-Warn if any functions that return structures or unions are defined or
-called. (In languages where you can return an array, this also elicits
-a warning.)
-.Ip "\fB\-Wstrict-prototypes (C only)\fR" 4
-.IX Item "-Wstrict-prototypes (C only)"
-Warn if a function is declared or defined without specifying the
-argument types. (An old-style function definition is permitted without
-a warning if preceded by a declaration which specifies the argument
-types.)
-.Ip "\fB\-Wmissing-prototypes (C only)\fR" 4
-.IX Item "-Wmissing-prototypes (C only)"
-Warn if a global function is defined without a previous prototype
-declaration. This warning is issued even if the definition itself
-provides a prototype. The aim is to detect global functions that fail
-to be declared in header files.
-.Ip "\fB\-Wmissing-declarations\fR" 4
-.IX Item "-Wmissing-declarations"
-Warn if a global function is defined without a previous declaration.
-Do so even if the definition itself provides a prototype.
-Use this option to detect global functions that are not declared in
-header files.
-.Ip "\fB\-Wmissing-noreturn\fR" 4
-.IX Item "-Wmissing-noreturn"
-Warn about functions which might be candidates for attribute \f(CW\*(C`noreturn\*(C'\fR.
-Note these are only possible candidates, not absolute ones. Care should
-be taken to manually verify functions actually do not ever return before
-adding the \f(CW\*(C`noreturn\*(C'\fR attribute, otherwise subtle code generation
-bugs could be introduced. You will not get a warning for \f(CW\*(C`main\*(C'\fR in
-hosted C environments.
-.Ip "\fB\-Wmissing-format-attribute\fR" 4
-.IX Item "-Wmissing-format-attribute"
-If \fB\-Wformat\fR is enabled, also warn about functions which might be
-candidates for \f(CW\*(C`format\*(C'\fR attributes. Note these are only possible
-candidates, not absolute ones. \s-1GCC\s0 will guess that \f(CW\*(C`format\*(C'\fR
-attributes might be appropriate for any function that calls a function
-like \f(CW\*(C`vprintf\*(C'\fR or \f(CW\*(C`vscanf\*(C'\fR, but this might not always be the
-case, and some functions for which \f(CW\*(C`format\*(C'\fR attributes are
-appropriate may not be detected. This option has no effect unless
-\&\fB\-Wformat\fR is enabled (possibly by \fB\-Wall\fR).
-.Ip "\fB\-Wpacked\fR" 4
-.IX Item "-Wpacked"
-Warn if a structure is given the packed attribute, but the packed
-attribute has no effect on the layout or size of the structure.
-Such structures may be mis-aligned for little benefit. For
-instance, in this code, the variable \f(CW\*(C`f.x\*(C'\fR in \f(CW\*(C`struct bar\*(C'\fR
-will be misaligned even though \f(CW\*(C`struct bar\*(C'\fR does not itself
-have the packed attribute:
-.Sp
-.Vb 8
-\& struct foo {
-\& int x;
-\& char a, b, c, d;
-\& } __attribute__((packed));
-\& struct bar {
-\& char z;
-\& struct foo f;
-\& };
-.Ve
-.Ip "\fB\-Wpadded\fR" 4
-.IX Item "-Wpadded"
-Warn if padding is included in a structure, either to align an element
-of the structure or to align the whole structure. Sometimes when this
-happens it is possible to rearrange the fields of the structure to
-reduce the padding and so make the structure smaller.
-.Ip "\fB\-Wredundant-decls\fR" 4
-.IX Item "-Wredundant-decls"
-Warn if anything is declared more than once in the same scope, even in
-cases where multiple declaration is valid and changes nothing.
-.Ip "\fB\-Wnested-externs (C only)\fR" 4
-.IX Item "-Wnested-externs (C only)"
-Warn if an \f(CW\*(C`extern\*(C'\fR declaration is encountered within a function.
-.Ip "\fB\-Wunreachable-code\fR" 4
-.IX Item "-Wunreachable-code"
-Warn if the compiler detects that code will never be executed.
-.Sp
-This option is intended to warn when the compiler detects that at
-least a whole line of source code will never be executed, because
-some condition is never satisfied or because it is after a
-procedure that never returns.
-.Sp
-It is possible for this option to produce a warning even though there
-are circumstances under which part of the affected line can be executed,
-so care should be taken when removing apparently-unreachable code.
-.Sp
-For instance, when a function is inlined, a warning may mean that the
-line is unreachable in only one inlined copy of the function.
-.Sp
-This option is not made part of \fB\-Wall\fR because in a debugging
-version of a program there is often substantial code which checks
-correct functioning of the program and is, hopefully, unreachable
-because the program does work. Another common use of unreachable
-code is to provide behaviour which is selectable at compile-time.
-.Ip "\fB\-Winline\fR" 4
-.IX Item "-Winline"
-Warn if a function can not be inlined and it was declared as inline.
-.Ip "\fB\-Wlong-long\fR" 4
-.IX Item "-Wlong-long"
-Warn if \fBlong long\fR type is used. This is default. To inhibit
-the warning messages, use \fB\-Wno-long-long\fR. Flags
-\&\fB\-Wlong-long\fR and \fB\-Wno-long-long\fR are taken into account
-only when \fB\-pedantic\fR flag is used.
-.Ip "\fB\-Wdisabled-optimization\fR" 4
-.IX Item "-Wdisabled-optimization"
-Warn if a requested optimization pass is disabled. This warning does
-not generally indicate that there is anything wrong with your code; it
-merely indicates that \s-1GCC\s0's optimizers were unable to handle the code
-effectively. Often, the problem is that your code is too big or too
-complex; \s-1GCC\s0 will refuse to optimize programs when the optimization
-itself is likely to take inordinate amounts of time.
-.Ip "\fB\-Werror\fR" 4
-.IX Item "-Werror"
-Make all warnings into errors.
-.Sh "Options for Debugging Your Program or \s-1GCC\s0"
-.IX Subsection "Options for Debugging Your Program or GCC"
-\&\s-1GCC\s0 has various special options that are used for debugging
-either your program or \s-1GCC:\s0
-.Ip "\fB\-g\fR" 4
-.IX Item "-g"
-Produce debugging information in the operating system's native format
-(stabs, \s-1COFF\s0, \s-1XCOFF\s0, or \s-1DWARF\s0). \s-1GDB\s0 can work with this debugging
-information.
-.Sp
-On most systems that use stabs format, \fB\-g\fR enables use of extra
-debugging information that only \s-1GDB\s0 can use; this extra information
-makes debugging work better in \s-1GDB\s0 but will probably make other debuggers
-crash or
-refuse to read the program. If you want to control for certain whether
-to generate the extra information, use \fB\-gstabs+\fR, \fB\-gstabs\fR,
-\&\fB\-gxcoff+\fR, \fB\-gxcoff\fR, \fB\-gdwarf-1+\fR, or \fB\-gdwarf-1\fR
-(see below).
-.Sp
-Unlike most other C compilers, \s-1GCC\s0 allows you to use \fB\-g\fR with
-\&\fB\-O\fR. The shortcuts taken by optimized code may occasionally
-produce surprising results: some variables you declared may not exist
-at all; flow of control may briefly move where you did not expect it;
-some statements may not be executed because they compute constant
-results or their values were already at hand; some statements may
-execute in different places because they were moved out of loops.
-.Sp
-Nevertheless it proves possible to debug optimized output. This makes
-it reasonable to use the optimizer for programs that might have bugs.
-.Sp
-The following options are useful when \s-1GCC\s0 is generated with the
-capability for more than one debugging format.
-.Ip "\fB\-ggdb\fR" 4
-.IX Item "-ggdb"
-Produce debugging information for use by \s-1GDB\s0. This means to use the
-most expressive format available (\s-1DWARF\s0 2, stabs, or the native format
-if neither of those are supported), including \s-1GDB\s0 extensions if at all
-possible.
-.Ip "\fB\-gstabs\fR" 4
-.IX Item "-gstabs"
-Produce debugging information in stabs format (if that is supported),
-without \s-1GDB\s0 extensions. This is the format used by \s-1DBX\s0 on most \s-1BSD\s0
-systems. On \s-1MIPS\s0, Alpha and System V Release 4 systems this option
-produces stabs debugging output which is not understood by \s-1DBX\s0 or \s-1SDB\s0.
-On System V Release 4 systems this option requires the \s-1GNU\s0 assembler.
-.Ip "\fB\-gstabs+\fR" 4
-.IX Item "-gstabs+"
-Produce debugging information in stabs format (if that is supported),
-using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger (\s-1GDB\s0). The
-use of these extensions is likely to make other debuggers crash or
-refuse to read the program.
-.Ip "\fB\-gcoff\fR" 4
-.IX Item "-gcoff"
-Produce debugging information in \s-1COFF\s0 format (if that is supported).
-This is the format used by \s-1SDB\s0 on most System V systems prior to
-System V Release 4.
-.Ip "\fB\-gxcoff\fR" 4
-.IX Item "-gxcoff"
-Produce debugging information in \s-1XCOFF\s0 format (if that is supported).
-This is the format used by the \s-1DBX\s0 debugger on \s-1IBM\s0 \s-1RS/6000\s0 systems.
-.Ip "\fB\-gxcoff+\fR" 4
-.IX Item "-gxcoff+"
-Produce debugging information in \s-1XCOFF\s0 format (if that is supported),
-using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger (\s-1GDB\s0). The
-use of these extensions is likely to make other debuggers crash or
-refuse to read the program, and may cause assemblers other than the \s-1GNU\s0
-assembler (\s-1GAS\s0) to fail with an error.
-.Ip "\fB\-gdwarf\fR" 4
-.IX Item "-gdwarf"
-Produce debugging information in \s-1DWARF\s0 version 1 format (if that is
-supported). This is the format used by \s-1SDB\s0 on most System V Release 4
-systems.
-.Ip "\fB\-gdwarf+\fR" 4
-.IX Item "-gdwarf+"
-Produce debugging information in \s-1DWARF\s0 version 1 format (if that is
-supported), using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger
-(\s-1GDB\s0). The use of these extensions is likely to make other debuggers
-crash or refuse to read the program.
-.Ip "\fB\-gdwarf-2\fR" 4
-.IX Item "-gdwarf-2"
-Produce debugging information in \s-1DWARF\s0 version 2 format (if that is
-supported). This is the format used by \s-1DBX\s0 on \s-1IRIX\s0 6.
-.Ip "\fB\-g\fR\fIlevel\fR" 4
-.IX Item "-glevel"
-.PD 0
-.Ip "\fB\-ggdb\fR\fIlevel\fR" 4
-.IX Item "-ggdblevel"
-.Ip "\fB\-gstabs\fR\fIlevel\fR" 4
-.IX Item "-gstabslevel"
-.Ip "\fB\-gcoff\fR\fIlevel\fR" 4
-.IX Item "-gcofflevel"
-.Ip "\fB\-gxcoff\fR\fIlevel\fR" 4
-.IX Item "-gxcofflevel"
-.Ip "\fB\-gdwarf\fR\fIlevel\fR" 4
-.IX Item "-gdwarflevel"
-.Ip "\fB\-gdwarf-2\fR\fIlevel\fR" 4
-.IX Item "-gdwarf-2level"
-.PD
-Request debugging information and also use \fIlevel\fR to specify how
-much information. The default level is 2.
-.Sp
-Level 1 produces minimal information, enough for making backtraces in
-parts of the program that you don't plan to debug. This includes
-descriptions of functions and external variables, but no information
-about local variables and no line numbers.
-.Sp
-Level 3 includes extra information, such as all the macro definitions
-present in the program. Some debuggers support macro expansion when
-you use \fB\-g3\fR.
-.Ip "\fB\-p\fR" 4
-.IX Item "-p"
-Generate extra code to write profile information suitable for the
-analysis program \f(CW\*(C`prof\*(C'\fR. You must use this option when compiling
-the source files you want data about, and you must also use it when
-linking.
-.Ip "\fB\-pg\fR" 4
-.IX Item "-pg"
-Generate extra code to write profile information suitable for the
-analysis program \f(CW\*(C`gprof\*(C'\fR. You must use this option when compiling
-the source files you want data about, and you must also use it when
-linking.
-.Ip "\fB\-a\fR" 4
-.IX Item "-a"
-Generate extra code to write profile information for basic blocks, which will
-record the number of times each basic block is executed, the basic block start
-address, and the function name containing the basic block. If \fB\-g\fR is
-used, the line number and filename of the start of the basic block will also be
-recorded. If not overridden by the machine description, the default action is
-to append to the text file \fIbb.out\fR.
-.Sp
-This data could be analyzed by a program like \f(CW\*(C`tcov\*(C'\fR. Note,
-however, that the format of the data is not what \f(CW\*(C`tcov\*(C'\fR expects.
-Eventually \s-1GNU\s0 \f(CW\*(C`gprof\*(C'\fR should be extended to process this data.
-.Ip "\fB\-Q\fR" 4
-.IX Item "-Q"
-Makes the compiler print out each function name as it is compiled, and
-print some statistics about each pass when it finishes.
-.Ip "\fB\-ftime-report\fR" 4
-.IX Item "-ftime-report"
-Makes the compiler print some statistics about the time consumed by each
-pass when it finishes.
-.Ip "\fB\-fmem-report\fR" 4
-.IX Item "-fmem-report"
-Makes the compiler print some statistics about permanent memory
-allocation when it finishes.
-.Ip "\fB\-ax\fR" 4
-.IX Item "-ax"
-Generate extra code to profile basic blocks. Your executable will
-produce output that is a superset of that produced when \fB\-a\fR is
-used. Additional output is the source and target address of the basic
-blocks where a jump takes place, the number of times a jump is executed,
-and (optionally) the complete sequence of basic blocks being executed.
-The output is appended to file \fIbb.out\fR.
-.Sp
-You can examine different profiling aspects without recompilation. Your
-executable will read a list of function names from file \fIbb.in\fR.
-Profiling starts when a function on the list is entered and stops when
-that invocation is exited. To exclude a function from profiling, prefix
-its name with \fB-\fR. If a function name is not unique, you can
-disambiguate it by writing it in the form
-\&\fB/path/filename.d:functionname\fR. Your executable will write the
-available paths and filenames in file \fIbb.out\fR.
-.Sp
-Several function names have a special meaning:
-.RS 4
-.if n .Ip "\f(CW""""_\|_bb_jumps_\|_""""\fR" 4
-.el .Ip "\f(CW_\|_bb_jumps_\|_\fR" 4
-.IX Item "__bb_jumps__"
-Write source, target and frequency of jumps to file \fIbb.out\fR.
-.if n .Ip "\f(CW""""_\|_bb_hidecall_\|_""""\fR" 4
-.el .Ip "\f(CW_\|_bb_hidecall_\|_\fR" 4
-.IX Item "__bb_hidecall__"
-Exclude function calls from frequency count.
-.if n .Ip "\f(CW""""_\|_bb_showret_\|_""""\fR" 4
-.el .Ip "\f(CW_\|_bb_showret_\|_\fR" 4
-.IX Item "__bb_showret__"
-Include function returns in frequency count.
-.if n .Ip "\f(CW""""_\|_bb_trace_\|_""""\fR" 4
-.el .Ip "\f(CW_\|_bb_trace_\|_\fR" 4
-.IX Item "__bb_trace__"
-Write the sequence of basic blocks executed to file \fIbbtrace.gz\fR.
-The file will be compressed using the program \fBgzip\fR, which must
-exist in your \fB\s-1PATH\s0\fR. On systems without the \fBpopen\fR
-function, the file will be named \fIbbtrace\fR and will not be
-compressed. \fBProfiling for even a few seconds on these systems
-will produce a very large file.\fR Note: \f(CW\*(C`_\|_bb_hidecall_\|_\*(C'\fR and
-\&\f(CW\*(C`_\|_bb_showret_\|_\*(C'\fR will not affect the sequence written to
-\&\fIbbtrace.gz\fR.
-.RE
-.RS 4
-.Sp
-Here's a short example using different profiling parameters
-in file \fIbb.in\fR. Assume function \f(CW\*(C`foo\*(C'\fR consists of basic blocks
-1 and 2 and is called twice from block 3 of function \f(CW\*(C`main\*(C'\fR. After
-the calls, block 3 transfers control to block 4 of \f(CW\*(C`main\*(C'\fR.
-.Sp
-With \f(CW\*(C`_\|_bb_trace_\|_\*(C'\fR and \f(CW\*(C`main\*(C'\fR contained in file \fIbb.in\fR,
-the following sequence of blocks is written to file \fIbbtrace.gz\fR:
-0 3 1 2 1 2 4. The return from block 2 to block 3 is not shown, because
-the return is to a point inside the block and not to the top. The
-block address 0 always indicates, that control is transferred
-to the trace from somewhere outside the observed functions. With
-\&\fB\-foo\fR added to \fIbb.in\fR, the blocks of function
-\&\f(CW\*(C`foo\*(C'\fR are removed from the trace, so only 0 3 4 remains.
-.Sp
-With \f(CW\*(C`_\|_bb_jumps_\|_\*(C'\fR and \f(CW\*(C`main\*(C'\fR contained in file \fIbb.in\fR,
-jump frequencies will be written to file \fIbb.out\fR. The
-frequencies are obtained by constructing a trace of blocks
-and incrementing a counter for every neighbouring pair of blocks
-in the trace. The trace 0 3 1 2 1 2 4 displays the following
-frequencies:
-.Sp
-.Vb 5
-\& Jump from block 0x0 to block 0x3 executed 1 time(s)
-\& Jump from block 0x3 to block 0x1 executed 1 time(s)
-\& Jump from block 0x1 to block 0x2 executed 2 time(s)
-\& Jump from block 0x2 to block 0x1 executed 1 time(s)
-\& Jump from block 0x2 to block 0x4 executed 1 time(s)
-.Ve
-With \f(CW\*(C`_\|_bb_hidecall_\|_\*(C'\fR, control transfer due to call instructions
-is removed from the trace, that is the trace is cut into three parts: 0
-3 4, 0 1 2 and 0 1 2. With \f(CW\*(C`_\|_bb_showret_\|_\*(C'\fR, control transfer due
-to return instructions is added to the trace. The trace becomes: 0 3 1
-2 3 1 2 3 4. Note, that this trace is not the same, as the sequence
-written to \fIbbtrace.gz\fR. It is solely used for counting jump
-frequencies.
-.RE
-.Ip "\fB\-fprofile-arcs\fR" 4
-.IX Item "-fprofile-arcs"
-Instrument \fIarcs\fR during compilation. For each function of your
-program, \s-1GCC\s0 creates a program flow graph, then finds a spanning tree
-for the graph. Only arcs that are not on the spanning tree have to be
-instrumented: the compiler adds code to count the number of times that these
-arcs are executed. When an arc is the only exit or only entrance to a
-block, the instrumentation code can be added to the block; otherwise, a
-new basic block must be created to hold the instrumentation code.
-.Sp
-Since not every arc in the program must be instrumented, programs
-compiled with this option run faster than programs compiled with
-\&\fB\-a\fR, which adds instrumentation code to every basic block in the
-program. The tradeoff: since \f(CW\*(C`gcov\*(C'\fR does not have
-execution counts for all branches, it must start with the execution
-counts for the instrumented branches, and then iterate over the program
-flow graph until the entire graph has been solved. Hence, \f(CW\*(C`gcov\*(C'\fR
-runs a little more slowly than a program which uses information from
-\&\fB\-a\fR.
-.Sp
-\&\fB\-fprofile-arcs\fR also makes it possible to estimate branch
-probabilities, and to calculate basic block execution counts. In
-general, basic block execution counts do not give enough information to
-estimate all branch probabilities. When the compiled program exits, it
-saves the arc execution counts to a file called
-\&\fI\fIsourcename\fI.da\fR. Use the compiler option
-\&\fB\-fbranch-probabilities\fR when recompiling, to optimize using estimated
-branch probabilities.
-.Ip "\fB\-ftest-coverage\fR" 4
-.IX Item "-ftest-coverage"
-Create data files for the \f(CW\*(C`gcov\*(C'\fR code-coverage utility.
-The data file names begin with the name of your source file:
-.RS 4
-.Ip "\fIsourcename\fR\fB.bb\fR" 4
-.IX Item "sourcename.bb"
-A mapping from basic blocks to line numbers, which \f(CW\*(C`gcov\*(C'\fR uses to
-associate basic block execution counts with line numbers.
-.Ip "\fIsourcename\fR\fB.bbg\fR" 4
-.IX Item "sourcename.bbg"
-A list of all arcs in the program flow graph. This allows \f(CW\*(C`gcov\*(C'\fR
-to reconstruct the program flow graph, so that it can compute all basic
-block and arc execution counts from the information in the
-\&\f(CW\*(C`\f(CIsourcename\f(CW.da\*(C'\fR file (this last file is the output from
-\&\fB\-fprofile-arcs\fR).
-.RE
-.RS 4
-.RE
-.Ip "\fB\-d\fR\fIletters\fR" 4
-.IX Item "-dletters"
-Says to make debugging dumps during compilation at times specified by
-\&\fIletters\fR. This is used for debugging the compiler. The file names
-for most of the dumps are made by appending a pass number and a word to
-the source file name (e.g. \fIfoo.c.00.rtl\fR or \fIfoo.c.01.sibling\fR).
-Here are the possible letters for use in \fIletters\fR, and their meanings:
-.RS 4
-.Ip "\fBA\fR" 4
-.IX Item "A"
-Annotate the assembler output with miscellaneous debugging information.
-.Ip "\fBb\fR" 4
-.IX Item "b"
-Dump after computing branch probabilities, to \fI\fIfile\fI.11.bp\fR.
-.Ip "\fBB\fR" 4
-.IX Item "B"
-Dump after block reordering, to \fI\fIfile\fI.26.bbro\fR.
-.Ip "\fBc\fR" 4
-.IX Item "c"
-Dump after instruction combination, to the file \fI\fIfile\fI.14.combine\fR.
-.Ip "\fBC\fR" 4
-.IX Item "C"
-Dump after the first if conversion, to the file \fI\fIfile\fI.15.ce\fR.
-.Ip "\fBd\fR" 4
-.IX Item "d"
-Dump after delayed branch scheduling, to \fI\fIfile\fI.29.dbr\fR.
-.Ip "\fBD\fR" 4
-.IX Item "D"
-Dump all macro definitions, at the end of preprocessing, in addition to
-normal output.
-.Ip "\fBe\fR" 4
-.IX Item "e"
-Dump after \s-1SSA\s0 optimizations, to \fI\fIfile\fI.05.ssa\fR and
-\&\fI\fIfile\fI.06.ussa\fR.
-.Ip "\fBE\fR" 4
-.IX Item "E"
-Dump after the second if conversion, to \fI\fIfile\fI.24.ce2\fR.
-.Ip "\fBf\fR" 4
-.IX Item "f"
-Dump after life analysis, to \fI\fIfile\fI.13.life\fR.
-.Ip "\fBF\fR" 4
-.IX Item "F"
-Dump after purging \f(CW\*(C`ADDRESSOF\*(C'\fR codes, to \fI\fIfile\fI.04.addressof\fR.
-.Ip "\fBg\fR" 4
-.IX Item "g"
-Dump after global register allocation, to \fI\fIfile\fI.19.greg\fR.
-.Ip "\fBo\fR" 4
-.IX Item "o"
-Dump after post-reload \s-1CSE\s0 and other optimizations, to \fI\fIfile\fI.20.postreload\fR.
-.Ip "\fBG\fR" 4
-.IX Item "G"
-Dump after \s-1GCSE\s0, to \fI\fIfile\fI.08.gcse\fR.
-.Ip "\fBi\fR" 4
-.IX Item "i"
-Dump after sibling call optimizations, to \fI\fIfile\fI.01.sibling\fR.
-.Ip "\fBj\fR" 4
-.IX Item "j"
-Dump after the first jump optimization, to \fI\fIfile\fI.02.jump\fR.
-.Ip "\fBJ\fR" 4
-.IX Item "J"
-Dump after the last jump optimization, to \fI\fIfile\fI.27.jump2\fR.
-.Ip "\fBk\fR" 4
-.IX Item "k"
-Dump after conversion from registers to stack, to \fI\fIfile\fI.29.stack\fR.
-.Ip "\fBl\fR" 4
-.IX Item "l"
-Dump after local register allocation, to \fI\fIfile\fI.18.lreg\fR.
-.Ip "\fBL\fR" 4
-.IX Item "L"
-Dump after loop optimization, to \fI\fIfile\fI.09.loop\fR.
-.Ip "\fBM\fR" 4
-.IX Item "M"
-Dump after performing the machine dependent reorganisation pass, to
-\&\fI\fIfile\fI.28.mach\fR.
-.Ip "\fBn\fR" 4
-.IX Item "n"
-Dump after register renumbering, to \fI\fIfile\fI.23.rnreg\fR.
-.Ip "\fBN\fR" 4
-.IX Item "N"
-Dump after the register move pass, to \fI\fIfile\fI.16.regmove\fR.
-.Ip "\fBr\fR" 4
-.IX Item "r"
-Dump after \s-1RTL\s0 generation, to \fI\fIfile\fI.00.rtl\fR.
-.Ip "\fBR\fR" 4
-.IX Item "R"
-Dump after the second instruction scheduling pass, to
-\&\fI\fIfile\fI.25.sched2\fR.
-.Ip "\fBs\fR" 4
-.IX Item "s"
-Dump after \s-1CSE\s0 (including the jump optimization that sometimes follows
-\&\s-1CSE\s0), to \fI\fIfile\fI.03.cse\fR.
-.Ip "\fBS\fR" 4
-.IX Item "S"
-Dump after the first instruction scheduling pass, to
-\&\fI\fIfile\fI.17.sched\fR.
-.Ip "\fBt\fR" 4
-.IX Item "t"
-Dump after the second \s-1CSE\s0 pass (including the jump optimization that
-sometimes follows \s-1CSE\s0), to \fI\fIfile\fI.10.cse2\fR.
-.Ip "\fBw\fR" 4
-.IX Item "w"
-Dump after the second flow pass, to \fI\fIfile\fI.21.flow2\fR.
-.Ip "\fBX\fR" 4
-.IX Item "X"
-Dump after dead code elimination, to \fI\fIfile\fI.06.dce\fR.
-.Ip "\fBz\fR" 4
-.IX Item "z"
-Dump after the peephole pass, to \fI\fIfile\fI.22.peephole2\fR.
-.Ip "\fBa\fR" 4
-.IX Item "a"
-Produce all the dumps listed above.
-.Ip "\fBm\fR" 4
-.IX Item "m"
-Print statistics on memory usage, at the end of the run, to
-standard error.
-.Ip "\fBp\fR" 4
-.IX Item "p"
-Annotate the assembler output with a comment indicating which
-pattern and alternative was used. The length of each instruction is
-also printed.
-.Ip "\fBP\fR" 4
-.IX Item "P"
-Dump the \s-1RTL\s0 in the assembler output as a comment before each instruction.
-Also turns on \fB\-dp\fR annotation.
-.Ip "\fBv\fR" 4
-.IX Item "v"
-For each of the other indicated dump files (except for
-\&\fI\fIfile\fI.00.rtl\fR), dump a representation of the control flow graph
-suitable for viewing with \s-1VCG\s0 to \fI\fIfile\fI.\fIpass\fI.vcg\fR.
-.Ip "\fBx\fR" 4
-.IX Item "x"
-Just generate \s-1RTL\s0 for a function instead of compiling it. Usually used
-with \fBr\fR.
-.Ip "\fBy\fR" 4
-.IX Item "y"
-Dump debugging information during parsing, to standard error.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-fdump-unnumbered\fR" 4
-.IX Item "-fdump-unnumbered"
-When doing debugging dumps (see \fB\-d\fR option above), suppress instruction
-numbers and line number note output. This makes it more feasible to
-use diff on debugging dumps for compiler invocations with different
-options, in particular with and without \fB\-g\fR.
-.Ip "\fB\-fdump-translation-unit (C and \*(C+ only)\fR" 4
-.IX Item "-fdump-translation-unit (C and only)"
-.PD 0
-.Ip "\fB\-fdump-translation-unit-\fR\fInumber\fR \fB(C and \*(C+ only)\fR" 4
-.IX Item "-fdump-translation-unit-number (C and only)"
-.PD
-Dump a representation of the tree structure for the entire translation
-unit to a file. The file name is made by appending \fI.tu\fR to the
-source file name. If the \fB-\fR\fInumber\fR form is used, \fInumber\fR
-controls the details of the dump as described for the \fB\-fdump-tree\fR options.
-.Ip "\fB\-fdump-class-hierarchy (\*(C+ only)\fR" 4
-.IX Item "-fdump-class-hierarchy ( only)"
-.PD 0
-.Ip "\fB\-fdump-class-hierarchy-\fR\fInumber\fR \fB(\*(C+ only)\fR" 4
-.IX Item "-fdump-class-hierarchy-number ( only)"
-.PD
-Dump a representation of each class's hierarchy and virtual function
-table layout to a file. The file name is made by appending \fI.class\fR
-to the source file name. If the \fB-\fR\fInumber\fR form is used, \fInumber\fR
-controls the details of the dump as described for the \fB\-fdump-tree\fR
-options.
-.Ip "\fB\-fdump-ast-\fR\fIswitch\fR \fB(\*(C+ only)\fR" 4
-.IX Item "-fdump-ast-switch ( only)"
-.PD 0
-.Ip "\fB\-fdump-ast-\fR\fIswitch\fR\fB-\fR\fInumber\fR \fB(\*(C+ only)\fR" 4
-.IX Item "-fdump-ast-switch-number ( only)"
-.PD
-Control the dumping at various stages of processing the abstract syntax
-tree to a file. The file name is generated by appending a switch
-specific suffix to the source file name. If the \fB-\fR\fInumber\fR form is
-used, \fInumber\fR is a bit mask which controls the details of the
-dump. The following bits are meaningful (these are not set symbolically,
-as the primary function of these dumps is for debugging gcc itself):
-.RS 4
-.Ip "\fBbit0 (1)\fR" 4
-.IX Item "bit0 (1)"
-Print the address of each node. Usually this is not meaningful as it
-changes according to the environment and source file.
-.Ip "\fBbit1 (2)\fR" 4
-.IX Item "bit1 (2)"
-Inhibit dumping of members of a scope or body of a function, unless they
-are reachable by some other path.
-.RE
-.RS 4
-.Sp
-The following tree dumps are possible:
-.RS 4
-.RE
-.Ip "\fBoriginal\fR" 4
-.IX Item "original"
-Dump before any tree based optimization, to \fI\fIfile\fI.original\fR.
-.Ip "\fBoptimized\fR" 4
-.IX Item "optimized"
-Dump after all tree based optimization, to \fI\fIfile\fI.optimized\fR.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-fpretend-float\fR" 4
-.IX Item "-fpretend-float"
-When running a cross-compiler, pretend that the target machine uses the
-same floating point format as the host machine. This causes incorrect
-output of the actual floating constants, but the actual instruction
-sequence will probably be the same as \s-1GCC\s0 would make when running on
-the target machine.
-.Ip "\fB\-save-temps\fR" 4
-.IX Item "-save-temps"
-Store the usual ``temporary'' intermediate files permanently; place them
-in the current directory and name them based on the source file. Thus,
-compiling \fIfoo.c\fR with \fB\-c \-save-temps\fR would produce files
-\&\fIfoo.i\fR and \fIfoo.s\fR, as well as \fIfoo.o\fR. This creates a
-preprocessed \fIfoo.i\fR output file even though the compiler now
-normally uses an integrated preprocessor.
-.Ip "\fB\-time\fR" 4
-.IX Item "-time"
-Report the \s-1CPU\s0 time taken by each subprocess in the compilation
-sequence. For C source files, this is the compiler proper and assembler
-(plus the linker if linking is done). The output looks like this:
-.Sp
-.Vb 2
-\& # cc1 0.12 0.01
-\& # as 0.00 0.01
-.Ve
-The first number on each line is the ``user time,'' that is time spent
-executing the program itself. The second number is ``system time,''
-time spent executing operating system routines on behalf of the program.
-Both numbers are in seconds.
-.Ip "\fB\-print-file-name=\fR\fIlibrary\fR" 4
-.IX Item "-print-file-name=library"
-Print the full absolute name of the library file \fIlibrary\fR that
-would be used when linking\-\-\-and don't do anything else. With this
-option, \s-1GCC\s0 does not compile or link anything; it just prints the
-file name.
-.Ip "\fB\-print-multi-directory\fR" 4
-.IX Item "-print-multi-directory"
-Print the directory name corresponding to the multilib selected by any
-other switches present in the command line. This directory is supposed
-to exist in \fB\s-1GCC_EXEC_PREFIX\s0\fR.
-.Ip "\fB\-print-multi-lib\fR" 4
-.IX Item "-print-multi-lib"
-Print the mapping from multilib directory names to compiler switches
-that enable them. The directory name is separated from the switches by
-\&\fB;\fR, and each switch starts with an \fB@} instead of the
-\&\f(CB@samp\fB{-\fR, without spaces between multiple switches. This is supposed to
-ease shell-processing.
-.Ip "\fB\-print-prog-name=\fR\fIprogram\fR" 4
-.IX Item "-print-prog-name=program"
-Like \fB\-print-file-name\fR, but searches for a program such as \fBcpp\fR.
-.Ip "\fB\-print-libgcc-file-name\fR" 4
-.IX Item "-print-libgcc-file-name"
-Same as \fB\-print-file-name=libgcc.a\fR.
-.Sp
-This is useful when you use \fB\-nostdlib\fR or \fB\-nodefaultlibs\fR
-but you do want to link with \fIlibgcc.a\fR. You can do
-.Sp
-.Vb 1
-\& gcc -nostdlib I<files>... `gcc -print-libgcc-file-name`
-.Ve
-.Ip "\fB\-print-search-dirs\fR" 4
-.IX Item "-print-search-dirs"
-Print the name of the configured installation directory and a list of
-program and library directories gcc will search\-\-\-and don't do anything else.
-.Sp
-This is useful when gcc prints the error message
-\&\fBinstallation problem, cannot exec cpp0: No such file or directory\fR.
-To resolve this you either need to put \fIcpp0\fR and the other compiler
-components where gcc expects to find them, or you can set the environment
-variable \fB\s-1GCC_EXEC_PREFIX\s0\fR to the directory where you installed them.
-Don't forget the trailing '/'.
-.Ip "\fB\-dumpmachine\fR" 4
-.IX Item "-dumpmachine"
-Print the compiler's target machine (for example,
-\&\fBi686\-pc-linux-gnu\fR)\-\-\-and don't do anything else.
-.Ip "\fB\-dumpversion\fR" 4
-.IX Item "-dumpversion"
-Print the compiler version (for example, \fB3.0\fR)\-\-\-and don't do
-anything else.
-.Ip "\fB\-dumpspecs\fR" 4
-.IX Item "-dumpspecs"
-Print the compiler's built-in specs\-\-\-and don't do anything else. (This
-is used when \s-1GCC\s0 itself is being built.)
-.Sh "Options That Control Optimization"
-.IX Subsection "Options That Control Optimization"
-These options control various sorts of optimizations:
-.Ip "\fB\-O\fR" 4
-.IX Item "-O"
-.PD 0
-.Ip "\fB\-O1\fR" 4
-.IX Item "-O1"
-.PD
-Optimize. Optimizing compilation takes somewhat more time, and a lot
-more memory for a large function.
-.Sp
-Without \fB\-O\fR, the compiler's goal is to reduce the cost of
-compilation and to make debugging produce the expected results.
-Statements are independent: if you stop the program with a breakpoint
-between statements, you can then assign a new value to any variable or
-change the program counter to any other statement in the function and
-get exactly the results you would expect from the source code.
-.Sp
-Without \fB\-O\fR, the compiler only allocates variables declared
-\&\f(CW\*(C`register\*(C'\fR in registers. The resulting compiled code is a little
-worse than produced by \s-1PCC\s0 without \fB\-O\fR.
-.Sp
-With \fB\-O\fR, the compiler tries to reduce code size and execution
-time.
-.Sp
-When you specify \fB\-O\fR, the compiler turns on \fB\-fthread-jumps\fR
-and \fB\-fdefer-pop\fR on all machines. The compiler turns on
-\&\fB\-fdelayed-branch\fR on machines that have delay slots, and
-\&\fB\-fomit-frame-pointer\fR on machines that can support debugging even
-without a frame pointer. On some machines the compiler also turns
-on other flags.
-.Ip "\fB\-O2\fR" 4
-.IX Item "-O2"
-Optimize even more. \s-1GCC\s0 performs nearly all supported optimizations
-that do not involve a space-speed tradeoff. The compiler does not
-perform loop unrolling or function inlining when you specify \fB\-O2\fR.
-As compared to \fB\-O\fR, this option increases both compilation time
-and the performance of the generated code.
-.Sp
-\&\fB\-O2\fR turns on all optional optimizations except for loop unrolling,
-function inlining, and register renaming. It also turns on the
-\&\fB\-fforce-mem\fR option on all machines and frame pointer elimination
-on machines where doing so does not interfere with debugging.
-.Ip "\fB\-O3\fR" 4
-.IX Item "-O3"
-Optimize yet more. \fB\-O3\fR turns on all optimizations specified by
-\&\fB\-O2\fR and also turns on the \fB\-finline-functions\fR and
-\&\fB\-frename-registers\fR options.
-.Ip "\fB\-O0\fR" 4
-.IX Item "-O0"
-Do not optimize.
-.Ip "\fB\-Os\fR" 4
-.IX Item "-Os"
-Optimize for size. \fB\-Os\fR enables all \fB\-O2\fR optimizations that
-do not typically increase code size. It also performs further
-optimizations designed to reduce code size.
-.Sp
-If you use multiple \fB\-O\fR options, with or without level numbers,
-the last such option is the one that is effective.
-.PP
-Options of the form \fB\-f\fR\fIflag\fR specify machine-independent
-flags. Most flags have both positive and negative forms; the negative
-form of \fB\-ffoo\fR would be \fB\-fno-foo\fR. In the table below,
-only one of the forms is listed\-\-\-the one which is not the default.
-You can figure out the other form by either removing \fBno-\fR or
-adding it.
-.Ip "\fB\-ffloat-store\fR" 4
-.IX Item "-ffloat-store"
-Do not store floating point variables in registers, and inhibit other
-options that might change whether a floating point value is taken from a
-register or memory.
-.Sp
-This option prevents undesirable excess precision on machines such as
-the 68000 where the floating registers (of the 68881) keep more
-precision than a \f(CW\*(C`double\*(C'\fR is supposed to have. Similarly for the
-x86 architecture. For most programs, the excess precision does only
-good, but a few programs rely on the precise definition of \s-1IEEE\s0 floating
-point. Use \fB\-ffloat-store\fR for such programs, after modifying
-them to store all pertinent intermediate computations into variables.
-.Ip "\fB\-fno-default-inline\fR" 4
-.IX Item "-fno-default-inline"
-Do not make member functions inline by default merely because they are
-defined inside the class scope (\*(C+ only). Otherwise, when you specify
-\&\fB\-O\fR, member functions defined inside class scope are compiled
-inline by default; i.e., you don't need to add \fBinline\fR in front of
-the member function name.
-.Ip "\fB\-fno-defer-pop\fR" 4
-.IX Item "-fno-defer-pop"
-Always pop the arguments to each function call as soon as that function
-returns. For machines which must pop arguments after a function call,
-the compiler normally lets arguments accumulate on the stack for several
-function calls and pops them all at once.
-.Ip "\fB\-fforce-mem\fR" 4
-.IX Item "-fforce-mem"
-Force memory operands to be copied into registers before doing
-arithmetic on them. This produces better code by making all memory
-references potential common subexpressions. When they are not common
-subexpressions, instruction combination should eliminate the separate
-register-load. The \fB\-O2\fR option turns on this option.
-.Ip "\fB\-fforce-addr\fR" 4
-.IX Item "-fforce-addr"
-Force memory address constants to be copied into registers before
-doing arithmetic on them. This may produce better code just as
-\&\fB\-fforce-mem\fR may.
-.Ip "\fB\-fomit-frame-pointer\fR" 4
-.IX Item "-fomit-frame-pointer"
-Don't keep the frame pointer in a register for functions that
-don't need one. This avoids the instructions to save, set up and
-restore frame pointers; it also makes an extra register available
-in many functions. \fBIt also makes debugging impossible on
-some machines.\fR
-.Sp
-On some machines, such as the Vax, this flag has no effect, because
-the standard calling sequence automatically handles the frame pointer
-and nothing is saved by pretending it doesn't exist. The
-machine-description macro \f(CW\*(C`FRAME_POINTER_REQUIRED\*(C'\fR controls
-whether a target machine supports this flag.
-.Ip "\fB\-foptimize-sibling-calls\fR" 4
-.IX Item "-foptimize-sibling-calls"
-Optimize sibling and tail recursive calls.
-.Ip "\fB\-ftrapv\fR" 4
-.IX Item "-ftrapv"
-This option generates traps for signed overflow on addition, subtraction,
-multiplication operations.
-.Ip "\fB\-fno-inline\fR" 4
-.IX Item "-fno-inline"
-Don't pay attention to the \f(CW\*(C`inline\*(C'\fR keyword. Normally this option
-is used to keep the compiler from expanding any functions inline.
-Note that if you are not optimizing, no functions can be expanded inline.
-.Ip "\fB\-finline-functions\fR" 4
-.IX Item "-finline-functions"
-Integrate all simple functions into their callers. The compiler
-heuristically decides which functions are simple enough to be worth
-integrating in this way.
-.Sp
-If all calls to a given function are integrated, and the function is
-declared \f(CW\*(C`static\*(C'\fR, then the function is normally not output as
-assembler code in its own right.
-.Ip "\fB\-finline-limit=\fR\fIn\fR" 4
-.IX Item "-finline-limit=n"
-By default, gcc limits the size of functions that can be inlined. This flag
-allows the control of this limit for functions that are explicitly marked as
-inline (ie marked with the inline keyword or defined within the class
-definition in c++). \fIn\fR is the size of functions that can be inlined in
-number of pseudo instructions (not counting parameter handling). The default
-value of n is 10000. Increasing this value can result in more inlined code at
-the cost of compilation time and memory consumption. Decreasing usually makes
-the compilation faster and less code will be inlined (which presumably
-means slower programs). This option is particularly useful for programs that
-use inlining heavily such as those based on recursive templates with c++.
-.Sp
-\&\fINote:\fR pseudo instruction represents, in this particular context, an
-abstract measurement of function's size. In no way, it represents a count
-of assembly instructions and as such its exact meaning might change from one
-release to an another.
-.Ip "\fB\-fkeep-inline-functions\fR" 4
-.IX Item "-fkeep-inline-functions"
-Even if all calls to a given function are integrated, and the function
-is declared \f(CW\*(C`static\*(C'\fR, nevertheless output a separate run-time
-callable version of the function. This switch does not affect
-\&\f(CW\*(C`extern inline\*(C'\fR functions.
-.Ip "\fB\-fkeep-static-consts\fR" 4
-.IX Item "-fkeep-static-consts"
-Emit variables declared \f(CW\*(C`static const\*(C'\fR when optimization isn't turned
-on, even if the variables aren't referenced.
-.Sp
-\&\s-1GCC\s0 enables this option by default. If you want to force the compiler to
-check if the variable was referenced, regardless of whether or not
-optimization is turned on, use the \fB\-fno-keep-static-consts\fR option.
-.Ip "\fB\-fno-function-cse\fR" 4
-.IX Item "-fno-function-cse"
-Do not put function addresses in registers; make each instruction that
-calls a constant function contain the function's address explicitly.
-.Sp
-This option results in less efficient code, but some strange hacks
-that alter the assembler output may be confused by the optimizations
-performed when this option is not used.
-.Ip "\fB\-ffast-math\fR" 4
-.IX Item "-ffast-math"
-Sets \fB\-fno-math-errno\fR, \fB\-funsafe-math-optimizations\fR,
-and \fB\-fno-trapping-math\fR.
-.Sp
-This option causes the preprocessor macro \f(CW\*(C`_\|_FAST_MATH_\|_\*(C'\fR to be defined.
-.Sp
-This option should never be turned on by any \fB\-O\fR option since
-it can result in incorrect output for programs which depend on
-an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for
-math functions.
-.Ip "\fB\-fno-math-errno\fR" 4
-.IX Item "-fno-math-errno"
-Do not set \s-1ERRNO\s0 after calling math functions that are executed
-with a single instruction, e.g., sqrt. A program that relies on
-\&\s-1IEEE\s0 exceptions for math error handling may want to use this flag
-for speed while maintaining \s-1IEEE\s0 arithmetic compatibility.
-.Sp
-This option should never be turned on by any \fB\-O\fR option since
-it can result in incorrect output for programs which depend on
-an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for
-math functions.
-.Sp
-The default is \fB\-fmath-errno\fR. The \fB\-ffast-math\fR option
-sets \fB\-fno-math-errno\fR.
-.Ip "\fB\-funsafe-math-optimizations\fR" 4
-.IX Item "-funsafe-math-optimizations"
-Allow optimizations for floating-point arithmetic that (a) assume
-that arguments and results are valid and (b) may violate \s-1IEEE\s0 or
-\&\s-1ANSI\s0 standards. When used at link-time, it may include libraries
-or startup files that change the default \s-1FPU\s0 control word or other
-similar optimizations.
-.Sp
-This option should never be turned on by any \fB\-O\fR option since
-it can result in incorrect output for programs which depend on
-an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for
-math functions.
-.Sp
-The default is \fB\-fno-unsafe-math-optimizations\fR. The
-\&\fB\-ffast-math\fR option sets \fB\-funsafe-math-optimizations\fR.
-.Ip "\fB\-fno-trapping-math\fR" 4
-.IX Item "-fno-trapping-math"
-Compile code assuming that floating-point operations cannot generate
-user-visible traps. Setting this option may allow faster code
-if one relies on ``non-stop'' \s-1IEEE\s0 arithmetic, for example.
-.Sp
-This option should never be turned on by any \fB\-O\fR option since
-it can result in incorrect output for programs which depend on
-an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for
-math functions.
-.Sp
-The default is \fB\-ftrapping-math\fR. The \fB\-ffast-math\fR
-option sets \fB\-fno-trapping-math\fR.
-.PP
-The following options control specific optimizations. The \fB\-O2\fR
-option turns on all of these optimizations except \fB\-funroll-loops\fR
-and \fB\-funroll-all-loops\fR. On most machines, the \fB\-O\fR option
-turns on the \fB\-fthread-jumps\fR and \fB\-fdelayed-branch\fR options,
-but specific machines may handle it differently.
-.PP
-You can use the following flags in the rare cases when ``fine-tuning''
-of optimizations to be performed is desired.
-.Ip "\fB\-fstrength-reduce\fR" 4
-.IX Item "-fstrength-reduce"
-Perform the optimizations of loop strength reduction and
-elimination of iteration variables.
-.Ip "\fB\-fthread-jumps\fR" 4
-.IX Item "-fthread-jumps"
-Perform optimizations where we check to see if a jump branches to a
-location where another comparison subsumed by the first is found. If
-so, the first branch is redirected to either the destination of the
-second branch or a point immediately following it, depending on whether
-the condition is known to be true or false.
-.Ip "\fB\-fcse-follow-jumps\fR" 4
-.IX Item "-fcse-follow-jumps"
-In common subexpression elimination, scan through jump instructions
-when the target of the jump is not reached by any other path. For
-example, when \s-1CSE\s0 encounters an \f(CW\*(C`if\*(C'\fR statement with an
-\&\f(CW\*(C`else\*(C'\fR clause, \s-1CSE\s0 will follow the jump when the condition
-tested is false.
-.Ip "\fB\-fcse-skip-blocks\fR" 4
-.IX Item "-fcse-skip-blocks"
-This is similar to \fB\-fcse-follow-jumps\fR, but causes \s-1CSE\s0 to
-follow jumps which conditionally skip over blocks. When \s-1CSE\s0
-encounters a simple \f(CW\*(C`if\*(C'\fR statement with no else clause,
-\&\fB\-fcse-skip-blocks\fR causes \s-1CSE\s0 to follow the jump around the
-body of the \f(CW\*(C`if\*(C'\fR.
-.Ip "\fB\-frerun-cse-after-loop\fR" 4
-.IX Item "-frerun-cse-after-loop"
-Re-run common subexpression elimination after loop optimizations has been
-performed.
-.Ip "\fB\-frerun-loop-opt\fR" 4
-.IX Item "-frerun-loop-opt"
-Run the loop optimizer twice.
-.Ip "\fB\-fgcse\fR" 4
-.IX Item "-fgcse"
-Perform a global common subexpression elimination pass.
-This pass also performs global constant and copy propagation.
-.Ip "\fB\-fgcse-lm\fR" 4
-.IX Item "-fgcse-lm"
-When \fB\-fgcse-lm\fR is enabled, global common subexpression elimination will
-attempt to move loads which are only killed by stores into themselves. This
-allows a loop containing a load/store sequence to be changed to a load outside
-the loop, and a copy/store within the loop.
-.Ip "\fB\-fgcse-sm\fR" 4
-.IX Item "-fgcse-sm"
-When \fB\-fgcse-sm\fR is enabled, A store motion pass is run after global common
-subexpression elimination. This pass will attempt to move stores out of loops.
-When used in conjunction with \fB\-fgcse-lm\fR, loops containing a load/store sequence
-can be changed to a load before the loop and a store after the loop.
-.Ip "\fB\-fdelete-null-pointer-checks\fR" 4
-.IX Item "-fdelete-null-pointer-checks"
-Use global dataflow analysis to identify and eliminate useless null
-pointer checks. Programs which rely on \s-1NULL\s0 pointer dereferences \fInot\fR
-halting the program may not work properly with this option. Use
-\&\-fno-delete-null-pointer-checks to disable this optimizing for programs
-which depend on that behavior.
-.Ip "\fB\-fexpensive-optimizations\fR" 4
-.IX Item "-fexpensive-optimizations"
-Perform a number of minor optimizations that are relatively expensive.
-.Ip "\fB\-foptimize-register-move\fR" 4
-.IX Item "-foptimize-register-move"
-.PD 0
-.Ip "\fB\-fregmove\fR" 4
-.IX Item "-fregmove"
-.PD
-Attempt to reassign register numbers in move instructions and as
-operands of other simple instructions in order to maximize the amount of
-register tying. This is especially helpful on machines with two-operand
-instructions. \s-1GCC\s0 enables this optimization by default with \fB\-O2\fR
-or higher.
-.Sp
-Note \fB\-fregmove\fR and \fB\-foptimize-register-move\fR are the same
-optimization.
-.Ip "\fB\-fdelayed-branch\fR" 4
-.IX Item "-fdelayed-branch"
-If supported for the target machine, attempt to reorder instructions
-to exploit instruction slots available after delayed branch
-instructions.
-.Ip "\fB\-fschedule-insns\fR" 4
-.IX Item "-fschedule-insns"
-If supported for the target machine, attempt to reorder instructions to
-eliminate execution stalls due to required data being unavailable. This
-helps machines that have slow floating point or memory load instructions
-by allowing other instructions to be issued until the result of the load
-or floating point instruction is required.
-.Ip "\fB\-fschedule-insns2\fR" 4
-.IX Item "-fschedule-insns2"
-Similar to \fB\-fschedule-insns\fR, but requests an additional pass of
-instruction scheduling after register allocation has been done. This is
-especially useful on machines with a relatively small number of
-registers and where memory load instructions take more than one cycle.
-.Ip "\fB\-ffunction-sections\fR" 4
-.IX Item "-ffunction-sections"
-.PD 0
-.Ip "\fB\-fdata-sections\fR" 4
-.IX Item "-fdata-sections"
-.PD
-Place each function or data item into its own section in the output
-file if the target supports arbitrary sections. The name of the
-function or the name of the data item determines the section's name
-in the output file.
-.Sp
-Use these options on systems where the linker can perform optimizations
-to improve locality of reference in the instruction space. \s-1HPPA\s0
-processors running \s-1HP-UX\s0 and Sparc processors running Solaris 2 have
-linkers with such optimizations. Other systems using the \s-1ELF\s0 object format
-as well as \s-1AIX\s0 may have these optimizations in the future.
-.Sp
-Only use these options when there are significant benefits from doing
-so. When you specify these options, the assembler and linker will
-create larger object and executable files and will also be slower.
-You will not be able to use \f(CW\*(C`gprof\*(C'\fR on all systems if you
-specify this option and you may have problems with debugging if
-you specify both this option and \fB\-g\fR.
-.Ip "\fB\-fcaller-saves\fR" 4
-.IX Item "-fcaller-saves"
-Enable values to be allocated in registers that will be clobbered by
-function calls, by emitting extra instructions to save and restore the
-registers around such calls. Such allocation is done only when it
-seems to result in better code than would otherwise be produced.
-.Sp
-This option is always enabled by default on certain machines, usually
-those which have no call-preserved registers to use instead.
-.Sp
-For all machines, optimization level 2 and higher enables this flag by
-default.
-.Ip "\fB\-funroll-loops\fR" 4
-.IX Item "-funroll-loops"
-Perform the optimization of loop unrolling. This is only done for loops
-whose number of iterations can be determined at compile time or run time.
-\&\fB\-funroll-loops\fR implies both \fB\-fstrength-reduce\fR and
-\&\fB\-frerun-cse-after-loop\fR.
-.Ip "\fB\-funroll-all-loops\fR" 4
-.IX Item "-funroll-all-loops"
-Perform the optimization of loop unrolling. This is done for all loops
-and usually makes programs run more slowly. \fB\-funroll-all-loops\fR
-implies \fB\-fstrength-reduce\fR as well as \fB\-frerun-cse-after-loop\fR.
-.Ip "\fB\-fmove-all-movables\fR" 4
-.IX Item "-fmove-all-movables"
-Forces all invariant computations in loops to be moved
-outside the loop.
-.Ip "\fB\-freduce-all-givs\fR" 4
-.IX Item "-freduce-all-givs"
-Forces all general-induction variables in loops to be
-strength-reduced.
-.Sp
-\&\fINote:\fR When compiling programs written in Fortran,
-\&\fB\-fmove-all-movables\fR and \fB\-freduce-all-givs\fR are enabled
-by default when you use the optimizer.
-.Sp
-These options may generate better or worse code; results are highly
-dependent on the structure of loops within the source code.
-.Sp
-These two options are intended to be removed someday, once
-they have helped determine the efficacy of various
-approaches to improving loop optimizations.
-.Sp
-Please let us (<\fBgcc@gcc.gnu.org\fR> and <\fBfortran@gnu.org\fR>)
-know how use of these options affects
-the performance of your production code.
-We're very interested in code that runs \fIslower\fR
-when these options are \fIenabled\fR.
-.Ip "\fB\-fno-peephole\fR" 4
-.IX Item "-fno-peephole"
-.PD 0
-.Ip "\fB\-fno-peephole2\fR" 4
-.IX Item "-fno-peephole2"
-.PD
-Disable any machine-specific peephole optimizations. The difference
-between \fB\-fno-peephole\fR and \fB\-fno-peephole2\fR is in how they
-are implemented in the compiler; some targets use one, some use the
-other, a few use both.
-.Ip "\fB\-fbranch-probabilities\fR" 4
-.IX Item "-fbranch-probabilities"
-After running a program compiled with \fB\-fprofile-arcs\fR, you can compile it a second time using
-\&\fB\-fbranch-probabilities\fR, to improve optimizations based on
-guessing the path a branch might take.
-.Ip "\fB\-fno-guess-branch-probability\fR" 4
-.IX Item "-fno-guess-branch-probability"
-Sometimes gcc will opt to guess branch probabilities when none are
-available from either profile directed feedback (\fB\-fprofile-arcs\fR)
-or \fB_\|_builtin_expect\fR. In a hard real-time system, people don't
-want different runs of the compiler to produce code that has different
-behavior; minimizing non-determinism is of paramount import. This
-switch allows users to reduce non-determinism, possibly at the expense
-of inferior optimization.
-.Ip "\fB\-fstrict-aliasing\fR" 4
-.IX Item "-fstrict-aliasing"
-Allows the compiler to assume the strictest aliasing rules applicable to
-the language being compiled. For C (and \*(C+), this activates
-optimizations based on the type of expressions. In particular, an
-object of one type is assumed never to reside at the same address as an
-object of a different type, unless the types are almost the same. For
-example, an \f(CW\*(C`unsigned int\*(C'\fR can alias an \f(CW\*(C`int\*(C'\fR, but not a
-\&\f(CW\*(C`void*\*(C'\fR or a \f(CW\*(C`double\*(C'\fR. A character type may alias any other
-type.
-.Sp
-Pay special attention to code like this:
-.Sp
-.Vb 4
-\& union a_union {
-\& int i;
-\& double d;
-\& };
-.Ve
-.Vb 5
-\& int f() {
-\& a_union t;
-\& t.d = 3.0;
-\& return t.i;
-\& }
-.Ve
-The practice of reading from a different union member than the one most
-recently written to (called ``type-punning'') is common. Even with
-\&\fB\-fstrict-aliasing\fR, type-punning is allowed, provided the memory
-is accessed through the union type. So, the code above will work as
-expected. However, this code might not:
-.Sp
-.Vb 7
-\& int f() {
-\& a_union t;
-\& int* ip;
-\& t.d = 3.0;
-\& ip = &t.i;
-\& return *ip;
-\& }
-.Ve
-.Ip "\fB\-falign-functions\fR" 4
-.IX Item "-falign-functions"
-.PD 0
-.Ip "\fB\-falign-functions=\fR\fIn\fR" 4
-.IX Item "-falign-functions=n"
-.PD
-Align the start of functions to the next power-of-two greater than
-\&\fIn\fR, skipping up to \fIn\fR bytes. For instance,
-\&\fB\-falign-functions=32\fR aligns functions to the next 32\-byte
-boundary, but \fB\-falign-functions=24\fR would align to the next
-32\-byte boundary only if this can be done by skipping 23 bytes or less.
-.Sp
-\&\fB\-fno-align-functions\fR and \fB\-falign-functions=1\fR are
-equivalent and mean that functions will not be aligned.
-.Sp
-Some assemblers only support this flag when \fIn\fR is a power of two;
-in that case, it is rounded up.
-.Sp
-If \fIn\fR is not specified, use a machine-dependent default.
-.Ip "\fB\-falign-labels\fR" 4
-.IX Item "-falign-labels"
-.PD 0
-.Ip "\fB\-falign-labels=\fR\fIn\fR" 4
-.IX Item "-falign-labels=n"
-.PD
-Align all branch targets to a power-of-two boundary, skipping up to
-\&\fIn\fR bytes like \fB\-falign-functions\fR. This option can easily
-make code slower, because it must insert dummy operations for when the
-branch target is reached in the usual flow of the code.
-.Sp
-If \fB\-falign-loops\fR or \fB\-falign-jumps\fR are applicable and
-are greater than this value, then their values are used instead.
-.Sp
-If \fIn\fR is not specified, use a machine-dependent default which is
-very likely to be \fB1\fR, meaning no alignment.
-.Ip "\fB\-falign-loops\fR" 4
-.IX Item "-falign-loops"
-.PD 0
-.Ip "\fB\-falign-loops=\fR\fIn\fR" 4
-.IX Item "-falign-loops=n"
-.PD
-Align loops to a power-of-two boundary, skipping up to \fIn\fR bytes
-like \fB\-falign-functions\fR. The hope is that the loop will be
-executed many times, which will make up for any execution of the dummy
-operations.
-.Sp
-If \fIn\fR is not specified, use a machine-dependent default.
-.Ip "\fB\-falign-jumps\fR" 4
-.IX Item "-falign-jumps"
-.PD 0
-.Ip "\fB\-falign-jumps=\fR\fIn\fR" 4
-.IX Item "-falign-jumps=n"
-.PD
-Align branch targets to a power-of-two boundary, for branch targets
-where the targets can only be reached by jumping, skipping up to \fIn\fR
-bytes like \fB\-falign-functions\fR. In this case, no dummy operations
-need be executed.
-.Sp
-If \fIn\fR is not specified, use a machine-dependent default.
-.Ip "\fB\-fssa\fR" 4
-.IX Item "-fssa"
-Perform optimizations in static single assignment form. Each function's
-flow graph is translated into \s-1SSA\s0 form, optimizations are performed, and
-the flow graph is translated back from \s-1SSA\s0 form. Users should not
-specify this option, since it is not yet ready for production use.
-.Ip "\fB\-fdce\fR" 4
-.IX Item "-fdce"
-Perform dead-code elimination in \s-1SSA\s0 form. Requires \fB\-fssa\fR. Like
-\&\fB\-fssa\fR, this is an experimental feature.
-.Ip "\fB\-fsingle-precision-constant\fR" 4
-.IX Item "-fsingle-precision-constant"
-Treat floating point constant as single precision constant instead of
-implicitly converting it to double precision constant.
-.Ip "\fB\-frename-registers\fR" 4
-.IX Item "-frename-registers"
-Attempt to avoid false dependencies in scheduled code by making use
-of registers left over after register allocation. This optimization
-will most benefit processors with lots of registers. It can, however,
-make debugging impossible, since variables will no longer stay in
-a ``home register''.
-.Ip "\fB\*(--param\fR \fIname\fR\fB=\fR\fIvalue\fR" 4
-.IX Item "param name=value"
-In some places, \s-1GCC\s0 uses various constants to control the amount of
-optimization that is done. For example, \s-1GCC\s0 will not inline functions
-that contain more that a certain number of instructions. You can
-control some of these constants on the command-line using the
-\&\fB\*(--param\fR option.
-.Sp
-In each case, the \fIvalue\fR is a integer. The allowable choices for
-\&\fIname\fR are given in the following table:
-.RS 4
-.Ip "\fBmax-delay-slot-insn-search\fR" 4
-.IX Item "max-delay-slot-insn-search"
-The maximum number of instructions to consider when looking for an
-instruction to fill a delay slot. If more than this arbitrary number of
-instructions is searched, the time savings from filling the delay slot
-will be minimal so stop searching. Increasing values mean more
-aggressive optimization, making the compile time increase with probably
-small improvement in executable run time.
-.Ip "\fBmax-delay-slot-live-search\fR" 4
-.IX Item "max-delay-slot-live-search"
-When trying to fill delay slots, the maximum number of instructions to
-consider when searching for a block with valid live register
-information. Increasing this arbitrarily chosen value means more
-aggressive optimization, increasing the compile time. This parameter
-should be removed when the delay slot code is rewritten to maintain the
-control-flow graph.
-.Ip "\fBmax-gcse-memory\fR" 4
-.IX Item "max-gcse-memory"
-The approximate maximum amount of memory that will be allocated in
-order to perform the global common subexpression elimination
-optimization. If more memory than specified is required, the
-optimization will not be done.
-.Ip "\fBmax-inline-insns\fR" 4
-.IX Item "max-inline-insns"
-If an function contains more than this many instructions, it
-will not be inlined. This option is precisely equivalent to
-\&\fB\-finline-limit\fR.
-.RE
-.RS 4
-.RE
-.Sh "Options Controlling the Preprocessor"
-.IX Subsection "Options Controlling the Preprocessor"
-These options control the C preprocessor, which is run on each C source
-file before actual compilation.
-.PP
-If you use the \fB\-E\fR option, nothing is done except preprocessing.
-Some of these options make sense only together with \fB\-E\fR because
-they cause the preprocessor output to be unsuitable for actual
-compilation.
-.Ip "\fB\-include\fR \fIfile\fR" 4
-.IX Item "-include file"
-Process \fIfile\fR as input before processing the regular input file.
-In effect, the contents of \fIfile\fR are compiled first. Any \fB\-D\fR
-and \fB\-U\fR options on the command line are always processed before
-\&\fB\-include\fR \fIfile\fR, regardless of the order in which they are
-written. All the \fB\-include\fR and \fB\-imacros\fR options are
-processed in the order in which they are written.
-.Ip "\fB\-imacros\fR \fIfile\fR" 4
-.IX Item "-imacros file"
-Process \fIfile\fR as input, discarding the resulting output, before
-processing the regular input file. Because the output generated from
-\&\fIfile\fR is discarded, the only effect of \fB\-imacros\fR \fIfile\fR
-is to make the macros defined in \fIfile\fR available for use in the
-main input. All the \fB\-include\fR and \fB\-imacros\fR options are
-processed in the order in which they are written.
-.Ip "\fB\-idirafter\fR \fIdir\fR" 4
-.IX Item "-idirafter dir"
-Add the directory \fIdir\fR to the second include path. The directories
-on the second include path are searched when a header file is not found
-in any of the directories in the main include path (the one that
-\&\fB\-I\fR adds to).
-.Ip "\fB\-iprefix\fR \fIprefix\fR" 4
-.IX Item "-iprefix prefix"
-Specify \fIprefix\fR as the prefix for subsequent \fB\-iwithprefix\fR
-options.
-.Ip "\fB\-iwithprefix\fR \fIdir\fR" 4
-.IX Item "-iwithprefix dir"
-Add a directory to the second include path. The directory's name is
-made by concatenating \fIprefix\fR and \fIdir\fR, where \fIprefix\fR was
-specified previously with \fB\-iprefix\fR. If you have not specified a
-prefix yet, the directory containing the installed passes of the
-compiler is used as the default.
-.Ip "\fB\-iwithprefixbefore\fR \fIdir\fR" 4
-.IX Item "-iwithprefixbefore dir"
-Add a directory to the main include path. The directory's name is made
-by concatenating \fIprefix\fR and \fIdir\fR, as in the case of
-\&\fB\-iwithprefix\fR.
-.Ip "\fB\-isystem\fR \fIdir\fR" 4
-.IX Item "-isystem dir"
-Add a directory to the beginning of the second include path, marking it
-as a system directory, so that it gets the same special treatment as
-is applied to the standard system directories.
-.Ip "\fB\-nostdinc\fR" 4
-.IX Item "-nostdinc"
-Do not search the standard system directories for header files. Only
-the directories you have specified with \fB\-I\fR options (and the
-current directory, if appropriate) are searched.
-.Sp
-By using both \fB\-nostdinc\fR and \fB\-I-\fR, you can limit the include-file
-search path to only those directories you specify explicitly.
-.Ip "\fB\-remap\fR" 4
-.IX Item "-remap"
-When searching for a header file in a directory, remap file names if a
-file named \fIheader.gcc\fR exists in that directory. This can be used
-to work around limitations of file systems with file name restrictions.
-The \fIheader.gcc\fR file should contain a series of lines with two
-tokens on each line: the first token is the name to map, and the second
-token is the actual name to use.
-.Ip "\fB\-undef\fR" 4
-.IX Item "-undef"
-Do not predefine any nonstandard macros. (Including architecture flags).
-.Ip "\fB\-E\fR" 4
-.IX Item "-E"
-Run only the C preprocessor. Preprocess all the C source files
-specified and output the results to standard output or to the
-specified output file.
-.Ip "\fB\-C\fR" 4
-.IX Item "-C"
-Tell the preprocessor not to discard comments. Used with the
-\&\fB\-E\fR option.
-.Ip "\fB\-P\fR" 4
-.IX Item "-P"
-Tell the preprocessor not to generate \fB#line\fR directives.
-Used with the \fB\-E\fR option.
-.Ip "\fB\-M\fR" 4
-.IX Item "-M"
-Instead of outputting the result of preprocessing, output a rule
-suitable for \f(CW\*(C`make\*(C'\fR describing the dependencies of the main source
-file. The preprocessor outputs one \f(CW\*(C`make\*(C'\fR rule containing the
-object file name for that source file, a colon, and the names of all the
-included files. Unless overridden explicitly, the object file name
-consists of the basename of the source file with any suffix replaced with
-object file suffix. If there are many included files then the
-rule is split into several lines using \fB\e\fR\-newline.
-.Sp
-\&\fB\-M\fR implies \fB\-E\fR.
-.Ip "\fB\-MM\fR" 4
-.IX Item "-MM"
-Like \fB\-M\fR, but mention only the files included with \fB#include
-"\fR\fIfile\fR\fB"\fR. System header files included with \fB#include
-<\fR\fIfile\fR\fB>\fR are omitted.
-.Ip "\fB\-MD\fR" 4
-.IX Item "-MD"
-Like \fB\-M\fR but the dependency information is written to a file
-rather than stdout. \f(CW\*(C`gcc\*(C'\fR will use the same file name and
-directory as the object file, but with the suffix \fI.d\fR instead.
-.Sp
-This is in addition to compiling the main file as specified\-\--\fB\-MD\fR
-does not inhibit ordinary compilation the way \fB\-M\fR does,
-unless you also specify \fB\-MG\fR.
-.Sp
-With Mach, you can use the utility \f(CW\*(C`md\*(C'\fR to merge multiple
-dependency files into a single dependency file suitable for using with
-the \fBmake\fR command.
-.Ip "\fB\-MMD\fR" 4
-.IX Item "-MMD"
-Like \fB\-MD\fR except mention only user header files, not system
-\&\-header files.
-.Ip "\fB\-MF\fR \fIfile\fR" 4
-.IX Item "-MF file"
-When used with \fB\-M\fR or \fB\-MM\fR, specifies a file to write the
-dependencies to. This allows the preprocessor to write the preprocessed
-file to stdout normally. If no \fB\-MF\fR switch is given, \s-1CPP\s0 sends
-the rules to stdout and suppresses normal preprocessed output.
-.Sp
-Another way to specify output of a \f(CW\*(C`make\*(C'\fR rule is by setting
-the environment variable \fB\s-1DEPENDENCIES_OUTPUT\s0\fR.
-.Ip "\fB\-MG\fR" 4
-.IX Item "-MG"
-When used with \fB\-M\fR or \fB\-MM\fR, \fB\-MG\fR says to treat missing
-header files as generated files and assume they live in the same
-directory as the source file. It suppresses preprocessed output, as a
-missing header file is ordinarily an error.
-.Sp
-This feature is used in automatic updating of makefiles.
-.Ip "\fB\-MP\fR" 4
-.IX Item "-MP"
-This option instructs \s-1CPP\s0 to add a phony target for each dependency
-other than the main file, causing each to depend on nothing. These
-dummy rules work around errors \f(CW\*(C`make\*(C'\fR gives if you remove header
-files without updating the \f(CW\*(C`Makefile\*(C'\fR to match.
-.Sp
-This is typical output:\-
-.Sp
-.Vb 1
-\& /tmp/test.o: /tmp/test.c /tmp/test.h
-.Ve
-.Vb 1
-\& /tmp/test.h:
-.Ve
-.Ip "\fB\-MQ\fR \fItarget\fR" 4
-.IX Item "-MQ target"
-.PD 0
-.Ip "\fB\-MT\fR \fItarget\fR" 4
-.IX Item "-MT target"
-.PD
-By default \s-1CPP\s0 uses the main file name, including any path, and appends
-the object suffix, normally ``.o'', to it to obtain the name of the
-target for dependency generation. With \fB\-MT\fR you can specify a
-target yourself, overriding the default one.
-.Sp
-If you want multiple targets, you can specify them as a single argument
-to \fB\-MT\fR, or use multiple \fB\-MT\fR options.
-.Sp
-The targets you specify are output in the order they appear on the
-command line. \fB\-MQ\fR is identical to \fB\-MT\fR, except that the
-target name is quoted for Make, but with \fB\-MT\fR it isn't. For
-example, \fB\-MT '$(objpfx)foo.o'\fR gives
-.Sp
-.Vb 1
-\& $(objpfx)foo.o: /tmp/foo.c
-.Ve
-but \fB\-MQ '$(objpfx)foo.o'\fR gives
-.Sp
-.Vb 1
-\& $$(objpfx)foo.o: /tmp/foo.c
-.Ve
-The default target is automatically quoted, as if it were given with
-\&\fB\-MQ\fR.
-.Ip "\fB\-H\fR" 4
-.IX Item "-H"
-Print the name of each header file used, in addition to other normal
-activities.
-.Ip "\fB\-A\fR\fIquestion\fR\fB(\fR\fIanswer\fR\fB)\fR" 4
-.IX Item "-Aquestion(answer)"
-Assert the answer \fIanswer\fR for \fIquestion\fR, in case it is tested
-with a preprocessing conditional such as \fB#if
-#\fR\fIquestion\fR\fB(\fR\fIanswer\fR\fB)\fR. \fB\-A-\fR disables the standard
-assertions that normally describe the target machine.
-.Ip "\fB\-D\fR\fImacro\fR" 4
-.IX Item "-Dmacro"
-Define macro \fImacro\fR with the string \fB1\fR as its definition.
-.Ip "\fB\-D\fR\fImacro\fR\fB=\fR\fIdefn\fR" 4
-.IX Item "-Dmacro=defn"
-Define macro \fImacro\fR as \fIdefn\fR. All instances of \fB\-D\fR on
-the command line are processed before any \fB\-U\fR options.
-.Sp
-Any \fB\-D\fR and \fB\-U\fR options on the command line are processed in
-order, and always before \fB\-imacros\fR \fIfile\fR, regardless of the
-order in which they are written.
-.Ip "\fB\-U\fR\fImacro\fR" 4
-.IX Item "-Umacro"
-Undefine macro \fImacro\fR. \fB\-U\fR options are evaluated after all
-\&\fB\-D\fR options, but before any \fB\-include\fR and \fB\-imacros\fR
-options.
-.Sp
-Any \fB\-D\fR and \fB\-U\fR options on the command line are processed in
-order, and always before \fB\-imacros\fR \fIfile\fR, regardless of the
-order in which they are written.
-.Ip "\fB\-dM\fR" 4
-.IX Item "-dM"
-Tell the preprocessor to output only a list of the macro definitions
-that are in effect at the end of preprocessing. Used with the \fB\-E\fR
-option.
-.Ip "\fB\-dD\fR" 4
-.IX Item "-dD"
-Tell the preprocessing to pass all macro definitions into the output, in
-their proper sequence in the rest of the output.
-.Ip "\fB\-dN\fR" 4
-.IX Item "-dN"
-Like \fB\-dD\fR except that the macro arguments and contents are omitted.
-Only \fB#define\fR \fIname\fR is included in the output.
-.Ip "\fB\-dI\fR" 4
-.IX Item "-dI"
-Output \fB#include\fR directives in addition to the result of
-preprocessing.
-.Ip "\fB\-fpreprocessed\fR" 4
-.IX Item "-fpreprocessed"
-Indicate to the preprocessor that the input file has already been
-preprocessed. This suppresses things like macro expansion, trigraph
-conversion, escaped newline splicing, and processing of most directives.
-The preprocessor still recognizes and removes comments, so that you can
-pass a file preprocessed with \fB\-C\fR to the compiler without
-problems. In this mode the integrated preprocessor is little more than
-a tokenizer for the front ends.
-.Sp
-\&\fB\-fpreprocessed\fR is implicit if the input file has one of the
-extensions \fBi\fR, \fBii\fR or \fBmi\fR. These are the extensions
-that \s-1GCC\s0 uses for preprocessed files created by \fB\-save-temps\fR.
-.Ip "\fB\-trigraphs\fR" 4
-.IX Item "-trigraphs"
-Process \s-1ISO\s0 standard trigraph sequences. These are three-character
-sequences, all starting with \fB??\fR, that are defined by \s-1ISO\s0 C to
-stand for single characters. For example, \fB??/\fR stands for
-\&\fB\e\fR, so \fB'??/n'\fR is a character constant for a newline. By
-default, \s-1GCC\s0 ignores trigraphs, but in standard-conforming modes it
-converts them. See the \fB\-std\fR and \fB\-ansi\fR options.
-.Sp
-The nine trigraph sequences are
-.RS 4
-.Ip "\fB??(\fR" 4
-.IX Item "??("
--> \fB[\fR
-.Ip "\fB??)\fR" 4
-.IX Item "??)"
--> \fB]\fR
-.Ip "\fB??<\fR" 4
-.IX Item "??<"
--> \fB{\fR
-.Ip "\fB??>\fR" 4
-.IX Item "??>"
--> \fB}\fR
-.Ip "\fB??=\fR" 4
-.IX Item "??="
--> \fB#\fR
-.Ip "\fB??/\fR" 4
-.IX Item "??/"
--> \fB\e\fR
-.Ip "\fB??'\fR" 4
-.IX Item "??'"
--> \fB^\fR
-.Ip "\fB??!\fR" 4
-.IX Item "??!"
--> \fB|\fR
-.Ip "\fB??-\fR" 4
-.IX Item "??-"
--> \fB~\fR
-.RE
-.RS 4
-.Sp
-Trigraph support is not popular, so many compilers do not implement it
-properly. Portable code should not rely on trigraphs being either
-converted or ignored.
-.RE
-.Ip "\fB\-Wp,\fR\fIoption\fR" 4
-.IX Item "-Wp,option"
-Pass \fIoption\fR as an option to the preprocessor. If \fIoption\fR
-contains commas, it is split into multiple options at the commas.
-.Sh "Passing Options to the Assembler"
-.IX Subsection "Passing Options to the Assembler"
-You can pass options to the assembler.
-.Ip "\fB\-Wa,\fR\fIoption\fR" 4
-.IX Item "-Wa,option"
-Pass \fIoption\fR as an option to the assembler. If \fIoption\fR
-contains commas, it is split into multiple options at the commas.
-.Sh "Options for Linking"
-.IX Subsection "Options for Linking"
-These options come into play when the compiler links object files into
-an executable output file. They are meaningless if the compiler is
-not doing a link step.
-.Ip "\fIobject-file-name\fR" 4
-.IX Item "object-file-name"
-A file name that does not end in a special recognized suffix is
-considered to name an object file or library. (Object files are
-distinguished from libraries by the linker according to the file
-contents.) If linking is done, these object files are used as input
-to the linker.
-.Ip "\fB\-c\fR" 4
-.IX Item "-c"
-.PD 0
-.Ip "\fB\-S\fR" 4
-.IX Item "-S"
-.Ip "\fB\-E\fR" 4
-.IX Item "-E"
-.PD
-If any of these options is used, then the linker is not run, and
-object file names should not be used as arguments.
-.Ip "\fB\-l\fR\fIlibrary\fR" 4
-.IX Item "-llibrary"
-.PD 0
-.Ip "\fB\-l\fR \fIlibrary\fR" 4
-.IX Item "-l library"
-.PD
-Search the library named \fIlibrary\fR when linking. (The second
-alternative with the library as a separate argument is only for
-\&\s-1POSIX\s0 compliance and is not recommended.)
-.Sp
-It makes a difference where in the command you write this option; the
-linker searches and processes libraries and object files in the order they
-are specified. Thus, \fBfoo.o \-lz bar.o\fR searches library \fBz\fR
-after file \fIfoo.o\fR but before \fIbar.o\fR. If \fIbar.o\fR refers
-to functions in \fBz\fR, those functions may not be loaded.
-.Sp
-The linker searches a standard list of directories for the library,
-which is actually a file named \fIlib\fIlibrary\fI.a\fR. The linker
-then uses this file as if it had been specified precisely by name.
-.Sp
-The directories searched include several standard system directories
-plus any that you specify with \fB\-L\fR.
-.Sp
-Normally the files found this way are library files\-\-\-archive files
-whose members are object files. The linker handles an archive file by
-scanning through it for members which define symbols that have so far
-been referenced but not defined. But if the file that is found is an
-ordinary object file, it is linked in the usual fashion. The only
-difference between using an \fB\-l\fR option and specifying a file name
-is that \fB\-l\fR surrounds \fIlibrary\fR with \fBlib\fR and \fB.a\fR
-and searches several directories.
-.Ip "\fB\-lobjc\fR" 4
-.IX Item "-lobjc"
-You need this special case of the \fB\-l\fR option in order to
-link an Objective-C program.
-.Ip "\fB\-nostartfiles\fR" 4
-.IX Item "-nostartfiles"
-Do not use the standard system startup files when linking.
-The standard system libraries are used normally, unless \fB\-nostdlib\fR
-or \fB\-nodefaultlibs\fR is used.
-.Ip "\fB\-nodefaultlibs\fR" 4
-.IX Item "-nodefaultlibs"
-Do not use the standard system libraries when linking.
-Only the libraries you specify will be passed to the linker.
-The standard startup files are used normally, unless \fB\-nostartfiles\fR
-is used. The compiler may generate calls to memcmp, memset, and memcpy
-for System V (and \s-1ISO\s0 C) environments or to bcopy and bzero for
-\&\s-1BSD\s0 environments. These entries are usually resolved by entries in
-libc. These entry points should be supplied through some other
-mechanism when this option is specified.
-.Ip "\fB\-nostdlib\fR" 4
-.IX Item "-nostdlib"
-Do not use the standard system startup files or libraries when linking.
-No startup files and only the libraries you specify will be passed to
-the linker. The compiler may generate calls to memcmp, memset, and memcpy
-for System V (and \s-1ISO\s0 C) environments or to bcopy and bzero for
-\&\s-1BSD\s0 environments. These entries are usually resolved by entries in
-libc. These entry points should be supplied through some other
-mechanism when this option is specified.
-.Sp
-One of the standard libraries bypassed by \fB\-nostdlib\fR and
-\&\fB\-nodefaultlibs\fR is \fIlibgcc.a\fR, a library of internal subroutines
-that \s-1GCC\s0 uses to overcome shortcomings of particular machines, or special
-needs for some languages.
-.Sp
-In most cases, you need \fIlibgcc.a\fR even when you want to avoid
-other standard libraries. In other words, when you specify \fB\-nostdlib\fR
-or \fB\-nodefaultlibs\fR you should usually specify \fB\-lgcc\fR as well.
-This ensures that you have no unresolved references to internal \s-1GCC\s0
-library subroutines. (For example, \fB_\|_main\fR, used to ensure \*(C+
-constructors will be called.)
-.Ip "\fB\-s\fR" 4
-.IX Item "-s"
-Remove all symbol table and relocation information from the executable.
-.Ip "\fB\-static\fR" 4
-.IX Item "-static"
-On systems that support dynamic linking, this prevents linking with the shared
-libraries. On other systems, this option has no effect.
-.Ip "\fB\-shared\fR" 4
-.IX Item "-shared"
-Produce a shared object which can then be linked with other objects to
-form an executable. Not all systems support this option. For predictable
-results, you must also specify the same set of options that were used to
-generate code (\fB\-fpic\fR, \fB\-fPIC\fR, or model suboptions)
-when you specify this option.[1]
-.Ip "\fB\-shared-libgcc\fR" 4
-.IX Item "-shared-libgcc"
-.PD 0
-.Ip "\fB\-static-libgcc\fR" 4
-.IX Item "-static-libgcc"
-.PD
-On systems that provide \fIlibgcc\fR as a shared library, these options
-force the use of either the shared or static version respectively.
-If no shared version of \fIlibgcc\fR was built when the compiler was
-configured, these options have no effect.
-.Sp
-There are several situations in which an application should use the
-shared \fIlibgcc\fR instead of the static version. The most common
-of these is when the application wishes to throw and catch exceptions
-across different shared libraries. In that case, each of the libraries
-as well as the application itself should use the shared \fIlibgcc\fR.
-.Sp
-Therefore, whenever you specify the \fB\-shared\fR option, the \s-1GCC\s0
-driver automatically adds \fB\-shared-libgcc\fR, unless you explicitly
-specify \fB\-static-libgcc\fR. The G++ driver automatically adds
-\&\fB\-shared-libgcc\fR when you build a main executable as well because
-for \*(C+ programs that is typically the right thing to do.
-(Exception-handling will not work reliably otherwise.)
-.Sp
-However, when linking a main executable written in C, you must
-explicitly say \fB\-shared-libgcc\fR if you want to use the shared
-\&\fIlibgcc\fR.
-.Ip "\fB\-symbolic\fR" 4
-.IX Item "-symbolic"
-Bind references to global symbols when building a shared object. Warn
-about any unresolved references (unless overridden by the link editor
-option \fB\-Xlinker \-z \-Xlinker defs\fR). Only a few systems support
-this option.
-.Ip "\fB\-Xlinker\fR \fIoption\fR" 4
-.IX Item "-Xlinker option"
-Pass \fIoption\fR as an option to the linker. You can use this to
-supply system-specific linker options which \s-1GCC\s0 does not know how to
-recognize.
-.Sp
-If you want to pass an option that takes an argument, you must use
-\&\fB\-Xlinker\fR twice, once for the option and once for the argument.
-For example, to pass \fB\-assert definitions\fR, you must write
-\&\fB\-Xlinker \-assert \-Xlinker definitions\fR. It does not work to write
-\&\fB\-Xlinker \*(L"\-assert definitions\*(R"\fR, because this passes the entire
-string as a single argument, which is not what the linker expects.
-.Ip "\fB\-Wl,\fR\fIoption\fR" 4
-.IX Item "-Wl,option"
-Pass \fIoption\fR as an option to the linker. If \fIoption\fR contains
-commas, it is split into multiple options at the commas.
-.Ip "\fB\-u\fR \fIsymbol\fR" 4
-.IX Item "-u symbol"
-Pretend the symbol \fIsymbol\fR is undefined, to force linking of
-library modules to define it. You can use \fB\-u\fR multiple times with
-different symbols to force loading of additional library modules.
-.Sh "Options for Directory Search"
-.IX Subsection "Options for Directory Search"
-These options specify directories to search for header files, for
-libraries and for parts of the compiler:
-.Ip "\fB\-I\fR\fIdir\fR" 4
-.IX Item "-Idir"
-Add the directory \fIdir\fR to the head of the list of directories to be
-searched for header files. This can be used to override a system header
-file, substituting your own version, since these directories are
-searched before the system header file directories. However, you should
-not use this option to add directories that contain vendor-supplied
-system header files (use \fB\-isystem\fR for that). If you use more than
-one \fB\-I\fR option, the directories are scanned in left-to-right
-order; the standard system directories come after.
-.Ip "\fB\-I-\fR" 4
-.IX Item "-I-"
-Any directories you specify with \fB\-I\fR options before the \fB\-I-\fR
-option are searched only for the case of \fB#include "\fR\fIfile\fR\fB"\fR;
-they are not searched for \fB#include <\fR\fIfile\fR\fB>\fR.
-.Sp
-If additional directories are specified with \fB\-I\fR options after
-the \fB\-I-\fR, these directories are searched for all \fB#include\fR
-directives. (Ordinarily \fIall\fR \fB\-I\fR directories are used
-this way.)
-.Sp
-In addition, the \fB\-I-\fR option inhibits the use of the current
-directory (where the current input file came from) as the first search
-directory for \fB#include "\fR\fIfile\fR\fB"\fR. There is no way to
-override this effect of \fB\-I-\fR. With \fB\-I.\fR you can specify
-searching the directory which was current when the compiler was
-invoked. That is not exactly the same as what the preprocessor does
-by default, but it is often satisfactory.
-.Sp
-\&\fB\-I-\fR does not inhibit the use of the standard system directories
-for header files. Thus, \fB\-I-\fR and \fB\-nostdinc\fR are
-independent.
-.Ip "\fB\-L\fR\fIdir\fR" 4
-.IX Item "-Ldir"
-Add directory \fIdir\fR to the list of directories to be searched
-for \fB\-l\fR.
-.Ip "\fB\-B\fR\fIprefix\fR" 4
-.IX Item "-Bprefix"
-This option specifies where to find the executables, libraries,
-include files, and data files of the compiler itself.
-.Sp
-The compiler driver program runs one or more of the subprograms
-\&\fIcpp\fR, \fIcc1\fR, \fIas\fR and \fIld\fR. It tries
-\&\fIprefix\fR as a prefix for each program it tries to run, both with and
-without \fImachine\fR\fB/\fR\fIversion\fR\fB/\fR.
-.Sp
-For each subprogram to be run, the compiler driver first tries the
-\&\fB\-B\fR prefix, if any. If that name is not found, or if \fB\-B\fR
-was not specified, the driver tries two standard prefixes, which are
-\&\fI/usr/lib/gcc/\fR and \fI/usr/local/lib/gcc-lib/\fR. If neither of
-those results in a file name that is found, the unmodified program
-name is searched for using the directories specified in your
-\&\fB\s-1PATH\s0\fR environment variable.
-.Sp
-\&\fB\-B\fR prefixes that effectively specify directory names also apply
-to libraries in the linker, because the compiler translates these
-options into \fB\-L\fR options for the linker. They also apply to
-includes files in the preprocessor, because the compiler translates these
-options into \fB\-isystem\fR options for the preprocessor. In this case,
-the compiler appends \fBinclude\fR to the prefix.
-.Sp
-The run-time support file \fIlibgcc.a\fR can also be searched for using
-the \fB\-B\fR prefix, if needed. If it is not found there, the two
-standard prefixes above are tried, and that is all. The file is left
-out of the link if it is not found by those means.
-.Sp
-Another way to specify a prefix much like the \fB\-B\fR prefix is to use
-the environment variable \fB\s-1GCC_EXEC_PREFIX\s0\fR.
-.Ip "\fB\-specs=\fR\fIfile\fR" 4
-.IX Item "-specs=file"
-Process \fIfile\fR after the compiler reads in the standard \fIspecs\fR
-file, in order to override the defaults that the \fIgcc\fR driver
-program uses when determining what switches to pass to \fIcc1\fR,
-\&\fIcc1plus\fR, \fIas\fR, \fIld\fR, etc. More than one
-\&\fB\-specs=\fR\fIfile\fR can be specified on the command line, and they
-are processed in order, from left to right.
-.Sh "Specifying Target Machine and Compiler Version"
-.IX Subsection "Specifying Target Machine and Compiler Version"
-By default, \s-1GCC\s0 compiles code for the same type of machine that you
-are using. However, it can also be installed as a cross-compiler, to
-compile for some other type of machine. In fact, several different
-configurations of \s-1GCC\s0, for different target machines, can be
-installed side by side. Then you specify which one to use with the
-\&\fB\-b\fR option.
-.PP
-In addition, older and newer versions of \s-1GCC\s0 can be installed side
-by side. One of them (probably the newest) will be the default, but
-you may sometimes wish to use another.
-.Ip "\fB\-b\fR \fImachine\fR" 4
-.IX Item "-b machine"
-The argument \fImachine\fR specifies the target machine for compilation.
-This is useful when you have installed \s-1GCC\s0 as a cross-compiler.
-.Sp
-The value to use for \fImachine\fR is the same as was specified as the
-machine type when configuring \s-1GCC\s0 as a cross-compiler. For
-example, if a cross-compiler was configured with \fBconfigure
-i386v\fR, meaning to compile for an 80386 running System V, then you
-would specify \fB\-b i386v\fR to run that cross compiler.
-.Sp
-When you do not specify \fB\-b\fR, it normally means to compile for
-the same type of machine that you are using.
-.Ip "\fB\-V\fR \fIversion\fR" 4
-.IX Item "-V version"
-The argument \fIversion\fR specifies which version of \s-1GCC\s0 to run.
-This is useful when multiple versions are installed. For example,
-\&\fIversion\fR might be \fB2.0\fR, meaning to run \s-1GCC\s0 version 2.0.
-.Sp
-The default version, when you do not specify \fB\-V\fR, is the last
-version of \s-1GCC\s0 that you installed.
-.PP
-The \fB\-b\fR and \fB\-V\fR options actually work by controlling part of
-the file name used for the executable files and libraries used for
-compilation. A given version of \s-1GCC\s0, for a given target machine, is
-normally kept in the directory \fI/usr/local/lib/gcc-lib/\fImachine\fI/\fIversion\fI\fR.
-.PP
-Thus, sites can customize the effect of \fB\-b\fR or \fB\-V\fR either by
-changing the names of these directories or adding alternate names (or
-symbolic links). If in directory \fI/usr/local/lib/gcc-lib/\fR the
-file \fI80386\fR is a link to the file \fIi386v\fR, then \fB\-b
-80386\fR becomes an alias for \fB\-b i386v\fR.
-.PP
-In one respect, the \fB\-b\fR or \fB\-V\fR do not completely change
-to a different compiler: the top-level driver program \fBgcc\fR
-that you originally invoked continues to run and invoke the other
-executables (preprocessor, compiler per se, assembler and linker)
-that do the real work. However, since no real work is done in the
-driver program, it usually does not matter that the driver program
-in use is not the one for the specified target. It is common for the
-interface to the other executables to change incompatibly between
-compiler versions, so unless the version specified is very close to that
-of the driver (for example, \fB\-V 3.0\fR with a driver program from \s-1GCC\s0
-version 3.0.1), use of \fB\-V\fR may not work; for example, using
-\&\fB\-V 2.95.2\fR will not work with a driver program from \s-1GCC\s0 3.0.
-.PP
-The only way that the driver program depends on the target machine is
-in the parsing and handling of special machine-specific options.
-However, this is controlled by a file which is found, along with the
-other executables, in the directory for the specified version and
-target machine. As a result, a single installed driver program adapts
-to any specified target machine, and sufficiently similar compiler
-versions.
-.PP
-The driver program executable does control one significant thing,
-however: the default version and target machine. Therefore, you can
-install different instances of the driver program, compiled for
-different targets or versions, under different names.
-.PP
-For example, if the driver for version 2.0 is installed as \fBogcc\fR
-and that for version 2.1 is installed as \fBgcc\fR, then the command
-\&\fBgcc\fR will use version 2.1 by default, while \fBogcc\fR will use
-2.0 by default. However, you can choose either version with either
-command with the \fB\-V\fR option.
-.Sh "Hardware Models and Configurations"
-.IX Subsection "Hardware Models and Configurations"
-Earlier we discussed the standard option \fB\-b\fR which chooses among
-different installed compilers for completely different target
-machines, such as Vax vs. 68000 vs. 80386.
-.PP
-In addition, each of these target machine types can have its own
-special options, starting with \fB\-m\fR, to choose among various
-hardware models or configurations\-\-\-for example, 68010 vs 68020,
-floating coprocessor or none. A single installed version of the
-compiler can compile for any model or configuration, according to the
-options specified.
-.PP
-Some configurations of the compiler also support additional special
-options, usually for compatibility with other compilers on the same
-platform.
-.PP
-.I "M680x0 Options"
-.IX Subsection "M680x0 Options"
-.PP
-These are the \fB\-m\fR options defined for the 68000 series. The default
-values for these options depends on which style of 68000 was selected when
-the compiler was configured; the defaults for the most common choices are
-given below.
-.Ip "\fB\-m68000\fR" 4
-.IX Item "-m68000"
-.PD 0
-.Ip "\fB\-mc68000\fR" 4
-.IX Item "-mc68000"
-.PD
-Generate output for a 68000. This is the default
-when the compiler is configured for 68000\-based systems.
-.Sp
-Use this option for microcontrollers with a 68000 or \s-1EC000\s0 core,
-including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.
-.Ip "\fB\-m68020\fR" 4
-.IX Item "-m68020"
-.PD 0
-.Ip "\fB\-mc68020\fR" 4
-.IX Item "-mc68020"
-.PD
-Generate output for a 68020. This is the default
-when the compiler is configured for 68020\-based systems.
-.Ip "\fB\-m68881\fR" 4
-.IX Item "-m68881"
-Generate output containing 68881 instructions for floating point.
-This is the default for most 68020 systems unless \fB\*(--nfp\fR was
-specified when the compiler was configured.
-.Ip "\fB\-m68030\fR" 4
-.IX Item "-m68030"
-Generate output for a 68030. This is the default when the compiler is
-configured for 68030\-based systems.
-.Ip "\fB\-m68040\fR" 4
-.IX Item "-m68040"
-Generate output for a 68040. This is the default when the compiler is
-configured for 68040\-based systems.
-.Sp
-This option inhibits the use of 68881/68882 instructions that have to be
-emulated by software on the 68040. Use this option if your 68040 does not
-have code to emulate those instructions.
-.Ip "\fB\-m68060\fR" 4
-.IX Item "-m68060"
-Generate output for a 68060. This is the default when the compiler is
-configured for 68060\-based systems.
-.Sp
-This option inhibits the use of 68020 and 68881/68882 instructions that
-have to be emulated by software on the 68060. Use this option if your 68060
-does not have code to emulate those instructions.
-.Ip "\fB\-mcpu32\fR" 4
-.IX Item "-mcpu32"
-Generate output for a \s-1CPU32\s0. This is the default
-when the compiler is configured for CPU32\-based systems.
-.Sp
-Use this option for microcontrollers with a
-\&\s-1CPU32\s0 or \s-1CPU32+\s0 core, including the 68330, 68331, 68332, 68333, 68334,
-68336, 68340, 68341, 68349 and 68360.
-.Ip "\fB\-m5200\fR" 4
-.IX Item "-m5200"
-Generate output for a 520X ``coldfire'' family cpu. This is the default
-when the compiler is configured for 520X-based systems.
-.Sp
-Use this option for microcontroller with a 5200 core, including
-the \s-1MCF5202\s0, \s-1MCF5203\s0, \s-1MCF5204\s0 and \s-1MCF5202\s0.
-.Ip "\fB\-m68020\-40\fR" 4
-.IX Item "-m68020-40"
-Generate output for a 68040, without using any of the new instructions.
-This results in code which can run relatively efficiently on either a
-68020/68881 or a 68030 or a 68040. The generated code does use the
-68881 instructions that are emulated on the 68040.
-.Ip "\fB\-m68020\-60\fR" 4
-.IX Item "-m68020-60"
-Generate output for a 68060, without using any of the new instructions.
-This results in code which can run relatively efficiently on either a
-68020/68881 or a 68030 or a 68040. The generated code does use the
-68881 instructions that are emulated on the 68060.
-.Ip "\fB\-mfpa\fR" 4
-.IX Item "-mfpa"
-Generate output containing Sun \s-1FPA\s0 instructions for floating point.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not available for all m68k
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this can't be done directly in cross-compilation. You must
-make your own arrangements to provide suitable library functions for
-cross-compilation. The embedded targets \fBm68k-*\-aout\fR and
-\&\fBm68k-*\-coff\fR do provide software floating point support.
-.Ip "\fB\-mshort\fR" 4
-.IX Item "-mshort"
-Consider type \f(CW\*(C`int\*(C'\fR to be 16 bits wide, like \f(CW\*(C`short int\*(C'\fR.
-.Ip "\fB\-mnobitfield\fR" 4
-.IX Item "-mnobitfield"
-Do not use the bit-field instructions. The \fB\-m68000\fR, \fB\-mcpu32\fR
-and \fB\-m5200\fR options imply \fB\-mnobitfield\fR.
-.Ip "\fB\-mbitfield\fR" 4
-.IX Item "-mbitfield"
-Do use the bit-field instructions. The \fB\-m68020\fR option implies
-\&\fB\-mbitfield\fR. This is the default if you use a configuration
-designed for a 68020.
-.Ip "\fB\-mrtd\fR" 4
-.IX Item "-mrtd"
-Use a different function-calling convention, in which functions
-that take a fixed number of arguments return with the \f(CW\*(C`rtd\*(C'\fR
-instruction, which pops their arguments while returning. This
-saves one instruction in the caller since there is no need to pop
-the arguments there.
-.Sp
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
-.Sp
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR);
-otherwise incorrect code will be generated for calls to those
-functions.
-.Sp
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
-.Sp
-The \f(CW\*(C`rtd\*(C'\fR instruction is supported by the 68010, 68020, 68030,
-68040, 68060 and \s-1CPU32\s0 processors, but not by the 68000 or 5200.
-.Ip "\fB\-malign-int\fR" 4
-.IX Item "-malign-int"
-.PD 0
-.Ip "\fB\-mno-align-int\fR" 4
-.IX Item "-mno-align-int"
-.PD
-Control whether \s-1GCC\s0 aligns \f(CW\*(C`int\*(C'\fR, \f(CW\*(C`long\*(C'\fR, \f(CW\*(C`long long\*(C'\fR,
-\&\f(CW\*(C`float\*(C'\fR, \f(CW\*(C`double\*(C'\fR, and \f(CW\*(C`long double\*(C'\fR variables on a 32\-bit
-boundary (\fB\-malign-int\fR) or a 16\-bit boundary (\fB\-mno-align-int\fR).
-Aligning variables on 32\-bit boundaries produces code that runs somewhat
-faster on processors with 32\-bit busses at the expense of more memory.
-.Sp
-\&\fBWarning:\fR if you use the \fB\-malign-int\fR switch, \s-1GCC\s0 will
-align structures containing the above types differently than
-most published application binary interface specifications for the m68k.
-.Ip "\fB\-mpcrel\fR" 4
-.IX Item "-mpcrel"
-Use the pc-relative addressing mode of the 68000 directly, instead of
-using a global offset table. At present, this option implies \fB\-fpic\fR,
-allowing at most a 16\-bit offset for pc-relative addressing. \fB\-fPIC\fR is
-not presently supported with \fB\-mpcrel\fR, though this could be supported for
-68020 and higher processors.
-.Ip "\fB\-mno-strict-align\fR" 4
-.IX Item "-mno-strict-align"
-.PD 0
-.Ip "\fB\-mstrict-align\fR" 4
-.IX Item "-mstrict-align"
-.PD
-Do not (do) assume that unaligned memory references will be handled by
-the system.
-.PP
-.I "M68hc1x Options"
-.IX Subsection "M68hc1x Options"
-.PP
-These are the \fB\-m\fR options defined for the 68hc11 and 68hc12
-microcontrollers. The default values for these options depends on
-which style of microcontroller was selected when the compiler was configured;
-the defaults for the most common choices are given below.
-.Ip "\fB\-m6811\fR" 4
-.IX Item "-m6811"
-.PD 0
-.Ip "\fB\-m68hc11\fR" 4
-.IX Item "-m68hc11"
-.PD
-Generate output for a 68HC11. This is the default
-when the compiler is configured for 68HC11\-based systems.
-.Ip "\fB\-m6812\fR" 4
-.IX Item "-m6812"
-.PD 0
-.Ip "\fB\-m68hc12\fR" 4
-.IX Item "-m68hc12"
-.PD
-Generate output for a 68HC12. This is the default
-when the compiler is configured for 68HC12\-based systems.
-.Ip "\fB\-mauto-incdec\fR" 4
-.IX Item "-mauto-incdec"
-Enable the use of 68HC12 pre and post auto-increment and auto-decrement
-addressing modes.
-.Ip "\fB\-mshort\fR" 4
-.IX Item "-mshort"
-Consider type \f(CW\*(C`int\*(C'\fR to be 16 bits wide, like \f(CW\*(C`short int\*(C'\fR.
-.Ip "\fB\-msoft-reg-count=\fR\fIcount\fR" 4
-.IX Item "-msoft-reg-count=count"
-Specify the number of pseudo-soft registers which are used for the
-code generation. The maximum number is 32. Using more pseudo-soft
-register may or may not result in better code depending on the program.
-The default is 4 for 68HC11 and 2 for 68HC12.
-.PP
-.I "\s-1VAX\s0 Options"
-.IX Subsection "VAX Options"
-.PP
-These \fB\-m\fR options are defined for the Vax:
-.Ip "\fB\-munix\fR" 4
-.IX Item "-munix"
-Do not output certain jump instructions (\f(CW\*(C`aobleq\*(C'\fR and so on)
-that the Unix assembler for the Vax cannot handle across long
-ranges.
-.Ip "\fB\-mgnu\fR" 4
-.IX Item "-mgnu"
-Do output those jump instructions, on the assumption that you
-will assemble with the \s-1GNU\s0 assembler.
-.Ip "\fB\-mg\fR" 4
-.IX Item "-mg"
-Output code for g-format floating point numbers instead of d-format.
-.PP
-.I "\s-1SPARC\s0 Options"
-.IX Subsection "SPARC Options"
-.PP
-These \fB\-m\fR switches are supported on the \s-1SPARC:\s0
-.Ip "\fB\-mno-app-regs\fR" 4
-.IX Item "-mno-app-regs"
-.PD 0
-.Ip "\fB\-mapp-regs\fR" 4
-.IX Item "-mapp-regs"
-.PD
-Specify \fB\-mapp-regs\fR to generate output using the global registers
-2 through 4, which the \s-1SPARC\s0 \s-1SVR4\s0 \s-1ABI\s0 reserves for applications. This
-is the default.
-.Sp
-To be fully \s-1SVR4\s0 \s-1ABI\s0 compliant at the cost of some performance loss,
-specify \fB\-mno-app-regs\fR. You should compile libraries and system
-software with this option.
-.Ip "\fB\-mfpu\fR" 4
-.IX Item "-mfpu"
-.PD 0
-.Ip "\fB\-mhard-float\fR" 4
-.IX Item "-mhard-float"
-.PD
-Generate output containing floating point instructions. This is the
-default.
-.Ip "\fB\-mno-fpu\fR" 4
-.IX Item "-mno-fpu"
-.PD 0
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-.PD
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not available for all \s-1SPARC\s0
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation. The embedded targets \fBsparc-*\-aout\fR and
-\&\fBsparclite-*\-*\fR do provide software floating point support.
-.Sp
-\&\fB\-msoft-float\fR changes the calling convention in the output file;
-therefore, it is only useful if you compile \fIall\fR of a program with
-this option. In particular, you need to compile \fIlibgcc.a\fR, the
-library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for
-this to work.
-.Ip "\fB\-mhard-quad-float\fR" 4
-.IX Item "-mhard-quad-float"
-Generate output containing quad-word (long double) floating point
-instructions.
-.Ip "\fB\-msoft-quad-float\fR" 4
-.IX Item "-msoft-quad-float"
-Generate output containing library calls for quad-word (long double)
-floating point instructions. The functions called are those specified
-in the \s-1SPARC\s0 \s-1ABI\s0. This is the default.
-.Sp
-As of this writing, there are no sparc implementations that have hardware
-support for the quad-word floating point instructions. They all invoke
-a trap handler for one of these instructions, and then the trap handler
-emulates the effect of the instruction. Because of the trap handler overhead,
-this is much slower than calling the \s-1ABI\s0 library routines. Thus the
-\&\fB\-msoft-quad-float\fR option is the default.
-.Ip "\fB\-mno-epilogue\fR" 4
-.IX Item "-mno-epilogue"
-.PD 0
-.Ip "\fB\-mepilogue\fR" 4
-.IX Item "-mepilogue"
-.PD
-With \fB\-mepilogue\fR (the default), the compiler always emits code for
-function exit at the end of each function. Any function exit in
-the middle of the function (such as a return statement in C) will
-generate a jump to the exit code at the end of the function.
-.Sp
-With \fB\-mno-epilogue\fR, the compiler tries to emit exit code inline
-at every function exit.
-.Ip "\fB\-mno-flat\fR" 4
-.IX Item "-mno-flat"
-.PD 0
-.Ip "\fB\-mflat\fR" 4
-.IX Item "-mflat"
-.PD
-With \fB\-mflat\fR, the compiler does not generate save/restore instructions
-and will use a ``flat'' or single register window calling convention.
-This model uses \f(CW%i7\fR as the frame pointer and is compatible with the normal
-register window model. Code from either may be intermixed.
-The local registers and the input registers (0\-5) are still treated as
-``call saved'' registers and will be saved on the stack as necessary.
-.Sp
-With \fB\-mno-flat\fR (the default), the compiler emits save/restore
-instructions (except for leaf functions) and is the normal mode of operation.
-.Ip "\fB\-mno-unaligned-doubles\fR" 4
-.IX Item "-mno-unaligned-doubles"
-.PD 0
-.Ip "\fB\-munaligned-doubles\fR" 4
-.IX Item "-munaligned-doubles"
-.PD
-Assume that doubles have 8 byte alignment. This is the default.
-.Sp
-With \fB\-munaligned-doubles\fR, \s-1GCC\s0 assumes that doubles have 8 byte
-alignment only if they are contained in another type, or if they have an
-absolute address. Otherwise, it assumes they have 4 byte alignment.
-Specifying this option avoids some rare compatibility problems with code
-generated by other compilers. It is not the default because it results
-in a performance loss, especially for floating point code.
-.Ip "\fB\-mno-faster-structs\fR" 4
-.IX Item "-mno-faster-structs"
-.PD 0
-.Ip "\fB\-mfaster-structs\fR" 4
-.IX Item "-mfaster-structs"
-.PD
-With \fB\-mfaster-structs\fR, the compiler assumes that structures
-should have 8 byte alignment. This enables the use of pairs of
-\&\f(CW\*(C`ldd\*(C'\fR and \f(CW\*(C`std\*(C'\fR instructions for copies in structure
-assignment, in place of twice as many \f(CW\*(C`ld\*(C'\fR and \f(CW\*(C`st\*(C'\fR pairs.
-However, the use of this changed alignment directly violates the Sparc
-\&\s-1ABI\s0. Thus, it's intended only for use on targets where the developer
-acknowledges that their resulting code will not be directly in line with
-the rules of the \s-1ABI\s0.
-.Ip "\fB\-mv8\fR" 4
-.IX Item "-mv8"
-.PD 0
-.Ip "\fB\-msparclite\fR" 4
-.IX Item "-msparclite"
-.PD
-These two options select variations on the \s-1SPARC\s0 architecture.
-.Sp
-By default (unless specifically configured for the Fujitsu SPARClite),
-\&\s-1GCC\s0 generates code for the v7 variant of the \s-1SPARC\s0 architecture.
-.Sp
-\&\fB\-mv8\fR will give you \s-1SPARC\s0 v8 code. The only difference from v7
-code is that the compiler emits the integer multiply and integer
-divide instructions which exist in \s-1SPARC\s0 v8 but not in \s-1SPARC\s0 v7.
-.Sp
-\&\fB\-msparclite\fR will give you SPARClite code. This adds the integer
-multiply, integer divide step and scan (\f(CW\*(C`ffs\*(C'\fR) instructions which
-exist in SPARClite but not in \s-1SPARC\s0 v7.
-.Sp
-These options are deprecated and will be deleted in a future \s-1GCC\s0 release.
-They have been replaced with \fB\-mcpu=xxx\fR.
-.Ip "\fB\-mcypress\fR" 4
-.IX Item "-mcypress"
-.PD 0
-.Ip "\fB\-msupersparc\fR" 4
-.IX Item "-msupersparc"
-.PD
-These two options select the processor for which the code is optimised.
-.Sp
-With \fB\-mcypress\fR (the default), the compiler optimizes code for the
-Cypress \s-1CY7C602\s0 chip, as used in the SparcStation/SparcServer 3xx series.
-This is also appropriate for the older SparcStation 1, 2, \s-1IPX\s0 etc.
-.Sp
-With \fB\-msupersparc\fR the compiler optimizes code for the SuperSparc cpu, as
-used in the SparcStation 10, 1000 and 2000 series. This flag also enables use
-of the full \s-1SPARC\s0 v8 instruction set.
-.Sp
-These options are deprecated and will be deleted in a future \s-1GCC\s0 release.
-They have been replaced with \fB\-mcpu=xxx\fR.
-.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4
-.IX Item "-mcpu=cpu_type"
-Set the instruction set, register set, and instruction scheduling parameters
-for machine type \fIcpu_type\fR. Supported values for \fIcpu_type\fR are
-\&\fBv7\fR, \fBcypress\fR, \fBv8\fR, \fBsupersparc\fR, \fBsparclite\fR,
-\&\fBhypersparc\fR, \fBsparclite86x\fR, \fBf930\fR, \fBf934\fR,
-\&\fBsparclet\fR, \fBtsc701\fR, \fBv9\fR, and \fBultrasparc\fR.
-.Sp
-Default instruction scheduling parameters are used for values that select
-an architecture and not an implementation. These are \fBv7\fR, \fBv8\fR,
-\&\fBsparclite\fR, \fBsparclet\fR, \fBv9\fR.
-.Sp
-Here is a list of each supported architecture and their supported
-implementations.
-.Sp
-.Vb 5
-\& v7: cypress
-\& v8: supersparc, hypersparc
-\& sparclite: f930, f934, sparclite86x
-\& sparclet: tsc701
-\& v9: ultrasparc
-.Ve
-.Ip "\fB\-mtune=\fR\fIcpu_type\fR" 4
-.IX Item "-mtune=cpu_type"
-Set the instruction scheduling parameters for machine type
-\&\fIcpu_type\fR, but do not set the instruction set or register set that the
-option \fB\-mcpu=\fR\fIcpu_type\fR would.
-.Sp
-The same values for \fB\-mcpu=\fR\fIcpu_type\fR are used for
-\&\fB\-mtune=\fR\fIcpu_type\fR, though the only useful values are those that
-select a particular cpu implementation: \fBcypress\fR, \fBsupersparc\fR,
-\&\fBhypersparc\fR, \fBf930\fR, \fBf934\fR, \fBsparclite86x\fR,
-\&\fBtsc701\fR, \fBultrasparc\fR.
-.PP
-These \fB\-m\fR switches are supported in addition to the above
-on the \s-1SPARCLET\s0 processor.
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-Generate code for a processor running in little-endian mode.
-.Ip "\fB\-mlive-g0\fR" 4
-.IX Item "-mlive-g0"
-Treat register \f(CW\*(C`%g0\*(C'\fR as a normal register.
-\&\s-1GCC\s0 will continue to clobber it as necessary but will not assume
-it always reads as 0.
-.Ip "\fB\-mbroken-saverestore\fR" 4
-.IX Item "-mbroken-saverestore"
-Generate code that does not use non-trivial forms of the \f(CW\*(C`save\*(C'\fR and
-\&\f(CW\*(C`restore\*(C'\fR instructions. Early versions of the \s-1SPARCLET\s0 processor do
-not correctly handle \f(CW\*(C`save\*(C'\fR and \f(CW\*(C`restore\*(C'\fR instructions used with
-arguments. They correctly handle them used without arguments. A \f(CW\*(C`save\*(C'\fR
-instruction used without arguments increments the current window pointer
-but does not allocate a new stack frame. It is assumed that the window
-overflow trap handler will properly handle this case as will interrupt
-handlers.
-.PP
-These \fB\-m\fR switches are supported in addition to the above
-on \s-1SPARC\s0 V9 processors in 64\-bit environments.
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-Generate code for a processor running in little-endian mode.
-.Ip "\fB\-m32\fR" 4
-.IX Item "-m32"
-.PD 0
-.Ip "\fB\-m64\fR" 4
-.IX Item "-m64"
-.PD
-Generate code for a 32\-bit or 64\-bit environment.
-The 32\-bit environment sets int, long and pointer to 32 bits.
-The 64\-bit environment sets int to 32 bits and long and pointer
-to 64 bits.
-.Ip "\fB\-mcmodel=medlow\fR" 4
-.IX Item "-mcmodel=medlow"
-Generate code for the Medium/Low code model: the program must be linked
-in the low 32 bits of the address space. Pointers are 64 bits.
-Programs can be statically or dynamically linked.
-.Ip "\fB\-mcmodel=medmid\fR" 4
-.IX Item "-mcmodel=medmid"
-Generate code for the Medium/Middle code model: the program must be linked
-in the low 44 bits of the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
-.Ip "\fB\-mcmodel=medany\fR" 4
-.IX Item "-mcmodel=medany"
-Generate code for the Medium/Anywhere code model: the program may be linked
-anywhere in the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
-.Ip "\fB\-mcmodel=embmedany\fR" 4
-.IX Item "-mcmodel=embmedany"
-Generate code for the Medium/Anywhere code model for embedded systems:
-assume a 32\-bit text and a 32\-bit data segment, both starting anywhere
-(determined at link time). Register \f(CW%g4\fR points to the base of the
-data segment. Pointers are still 64 bits.
-Programs are statically linked, \s-1PIC\s0 is not supported.
-.Ip "\fB\-mstack-bias\fR" 4
-.IX Item "-mstack-bias"
-.PD 0
-.Ip "\fB\-mno-stack-bias\fR" 4
-.IX Item "-mno-stack-bias"
-.PD
-With \fB\-mstack-bias\fR, \s-1GCC\s0 assumes that the stack pointer, and
-frame pointer if present, are offset by \-2047 which must be added back
-when making stack frame references.
-Otherwise, assume no such offset is present.
-.PP
-.I "Convex Options"
-.IX Subsection "Convex Options"
-.PP
-These \fB\-m\fR options are defined for Convex:
-.Ip "\fB\-mc1\fR" 4
-.IX Item "-mc1"
-Generate output for C1. The code will run on any Convex machine.
-The preprocessor symbol \f(CW\*(C`_\|_convex_\|_c1_\|_\*(C'\fR is defined.
-.Ip "\fB\-mc2\fR" 4
-.IX Item "-mc2"
-Generate output for C2. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C2.
-The preprocessor symbol \f(CW\*(C`_\|_convex_c2_\|_\*(C'\fR is defined.
-.Ip "\fB\-mc32\fR" 4
-.IX Item "-mc32"
-Generate output for C32xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C32.
-The preprocessor symbol \f(CW\*(C`_\|_convex_c32_\|_\*(C'\fR is defined.
-.Ip "\fB\-mc34\fR" 4
-.IX Item "-mc34"
-Generate output for C34xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C34.
-The preprocessor symbol \f(CW\*(C`_\|_convex_c34_\|_\*(C'\fR is defined.
-.Ip "\fB\-mc38\fR" 4
-.IX Item "-mc38"
-Generate output for C38xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C38.
-The preprocessor symbol \f(CW\*(C`_\|_convex_c38_\|_\*(C'\fR is defined.
-.Ip "\fB\-margcount\fR" 4
-.IX Item "-margcount"
-Generate code which puts an argument count in the word preceding each
-argument list. This is compatible with regular \s-1CC\s0, and a few programs
-may need the argument count word. \s-1GDB\s0 and other source-level debuggers
-do not need it; this info is in the symbol table.
-.Ip "\fB\-mnoargcount\fR" 4
-.IX Item "-mnoargcount"
-Omit the argument count word. This is the default.
-.Ip "\fB\-mvolatile-cache\fR" 4
-.IX Item "-mvolatile-cache"
-Allow volatile references to be cached. This is the default.
-.Ip "\fB\-mvolatile-nocache\fR" 4
-.IX Item "-mvolatile-nocache"
-Volatile references bypass the data cache, going all the way to memory.
-This is only needed for multi-processor code that does not use standard
-synchronization instructions. Making non-volatile references to volatile
-locations will not necessarily work.
-.Ip "\fB\-mlong32\fR" 4
-.IX Item "-mlong32"
-Type long is 32 bits, the same as type int. This is the default.
-.Ip "\fB\-mlong64\fR" 4
-.IX Item "-mlong64"
-Type long is 64 bits, the same as type long long. This option is useless,
-because no library support exists for it.
-.PP
-.I "\s-1AMD29K\s0 Options"
-.IX Subsection "AMD29K Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1AMD\s0 Am29000:
-.Ip "\fB\-mdw\fR" 4
-.IX Item "-mdw"
-Generate code that assumes the \f(CW\*(C`DW\*(C'\fR bit is set, i.e., that byte and
-halfword operations are directly supported by the hardware. This is the
-default.
-.Ip "\fB\-mndw\fR" 4
-.IX Item "-mndw"
-Generate code that assumes the \f(CW\*(C`DW\*(C'\fR bit is not set.
-.Ip "\fB\-mbw\fR" 4
-.IX Item "-mbw"
-Generate code that assumes the system supports byte and halfword write
-operations. This is the default.
-.Ip "\fB\-mnbw\fR" 4
-.IX Item "-mnbw"
-Generate code that assumes the systems does not support byte and
-halfword write operations. \fB\-mnbw\fR implies \fB\-mndw\fR.
-.Ip "\fB\-msmall\fR" 4
-.IX Item "-msmall"
-Use a small memory model that assumes that all function addresses are
-either within a single 256 \s-1KB\s0 segment or at an absolute address of less
-than 256k. This allows the \f(CW\*(C`call\*(C'\fR instruction to be used instead
-of a \f(CW\*(C`const\*(C'\fR, \f(CW\*(C`consth\*(C'\fR, \f(CW\*(C`calli\*(C'\fR sequence.
-.Ip "\fB\-mnormal\fR" 4
-.IX Item "-mnormal"
-Use the normal memory model: Generate \f(CW\*(C`call\*(C'\fR instructions only when
-calling functions in the same file and \f(CW\*(C`calli\*(C'\fR instructions
-otherwise. This works if each file occupies less than 256 \s-1KB\s0 but allows
-the entire executable to be larger than 256 \s-1KB\s0. This is the default.
-.Ip "\fB\-mlarge\fR" 4
-.IX Item "-mlarge"
-Always use \f(CW\*(C`calli\*(C'\fR instructions. Specify this option if you expect
-a single file to compile into more than 256 \s-1KB\s0 of code.
-.Ip "\fB\-m29050\fR" 4
-.IX Item "-m29050"
-Generate code for the Am29050.
-.Ip "\fB\-m29000\fR" 4
-.IX Item "-m29000"
-Generate code for the Am29000. This is the default.
-.Ip "\fB\-mkernel-registers\fR" 4
-.IX Item "-mkernel-registers"
-Generate references to registers \f(CW\*(C`gr64\-gr95\*(C'\fR instead of to
-registers \f(CW\*(C`gr96\-gr127\*(C'\fR. This option can be used when compiling
-kernel code that wants a set of global registers disjoint from that used
-by user-mode code.
-.Sp
-Note that when this option is used, register names in \fB\-f\fR flags
-must use the normal, user-mode, names.
-.Ip "\fB\-muser-registers\fR" 4
-.IX Item "-muser-registers"
-Use the normal set of global registers, \f(CW\*(C`gr96\-gr127\*(C'\fR. This is the
-default.
-.Ip "\fB\-mstack-check\fR" 4
-.IX Item "-mstack-check"
-.PD 0
-.Ip "\fB\-mno-stack-check\fR" 4
-.IX Item "-mno-stack-check"
-.PD
-Insert (or do not insert) a call to \f(CW\*(C`_\|_msp_check\*(C'\fR after each stack
-adjustment. This is often used for kernel code.
-.Ip "\fB\-mstorem-bug\fR" 4
-.IX Item "-mstorem-bug"
-.PD 0
-.Ip "\fB\-mno-storem-bug\fR" 4
-.IX Item "-mno-storem-bug"
-.PD
-\&\fB\-mstorem-bug\fR handles 29k processors which cannot handle the
-separation of a mtsrim insn and a storem instruction (most 29000 chips
-to date, but not the 29050).
-.Ip "\fB\-mno-reuse-arg-regs\fR" 4
-.IX Item "-mno-reuse-arg-regs"
-.PD 0
-.Ip "\fB\-mreuse-arg-regs\fR" 4
-.IX Item "-mreuse-arg-regs"
-.PD
-\&\fB\-mno-reuse-arg-regs\fR tells the compiler to only use incoming argument
-registers for copying out arguments. This helps detect calling a function
-with fewer arguments than it was declared with.
-.Ip "\fB\-mno-impure-text\fR" 4
-.IX Item "-mno-impure-text"
-.PD 0
-.Ip "\fB\-mimpure-text\fR" 4
-.IX Item "-mimpure-text"
-.PD
-\&\fB\-mimpure-text\fR, used in addition to \fB\-shared\fR, tells the compiler to
-not pass \fB\-assert pure-text\fR to the linker when linking a shared object.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
-.Ip "\fB\-mno-multm\fR" 4
-.IX Item "-mno-multm"
-Do not generate multm or multmu instructions. This is useful for some embedded
-systems which do not have trap handlers for these instructions.
-.PP
-.I "\s-1ARM\s0 Options"
-.IX Subsection "ARM Options"
-.PP
-These \fB\-m\fR options are defined for Advanced \s-1RISC\s0 Machines (\s-1ARM\s0)
-architectures:
-.Ip "\fB\-mapcs-frame\fR" 4
-.IX Item "-mapcs-frame"
-Generate a stack frame that is compliant with the \s-1ARM\s0 Procedure Call
-Standard for all functions, even if this is not strictly necessary for
-correct execution of the code. Specifying \fB\-fomit-frame-pointer\fR
-with this option will cause the stack frames not to be generated for
-leaf functions. The default is \fB\-mno-apcs-frame\fR.
-.Ip "\fB\-mapcs\fR" 4
-.IX Item "-mapcs"
-This is a synonym for \fB\-mapcs-frame\fR.
-.Ip "\fB\-mapcs-26\fR" 4
-.IX Item "-mapcs-26"
-Generate code for a processor running with a 26\-bit program counter,
-and conforming to the function calling standards for the \s-1APCS\s0 26\-bit
-option. This option replaces the \fB\-m2\fR and \fB\-m3\fR options
-of previous releases of the compiler.
-.Ip "\fB\-mapcs-32\fR" 4
-.IX Item "-mapcs-32"
-Generate code for a processor running with a 32\-bit program counter,
-and conforming to the function calling standards for the \s-1APCS\s0 32\-bit
-option. This option replaces the \fB\-m6\fR option of previous releases
-of the compiler.
-.Ip "\fB\-mthumb-interwork\fR" 4
-.IX Item "-mthumb-interwork"
-Generate code which supports calling between the \s-1ARM\s0 and Thumb
-instruction sets. Without this option the two instruction sets cannot
-be reliably used inside one program. The default is
-\&\fB\-mno-thumb-interwork\fR, since slightly larger code is generated
-when \fB\-mthumb-interwork\fR is specified.
-.Ip "\fB\-mno-sched-prolog\fR" 4
-.IX Item "-mno-sched-prolog"
-Prevent the reordering of instructions in the function prolog, or the
-merging of those instruction with the instructions in the function's
-body. This means that all functions will start with a recognizable set
-of instructions (or in fact one of a choice from a small set of
-different function prologues), and this information can be used to
-locate the start if functions inside an executable piece of code. The
-default is \fB\-msched-prolog\fR.
-.Ip "\fB\-mhard-float\fR" 4
-.IX Item "-mhard-float"
-Generate output containing floating point instructions. This is the
-default.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not available for all \s-1ARM\s0
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation.
-.Sp
-\&\fB\-msoft-float\fR changes the calling convention in the output file;
-therefore, it is only useful if you compile \fIall\fR of a program with
-this option. In particular, you need to compile \fIlibgcc.a\fR, the
-library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for
-this to work.
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-Generate code for a processor running in little-endian mode. This is
-the default for all standard configurations.
-.Ip "\fB\-mbig-endian\fR" 4
-.IX Item "-mbig-endian"
-Generate code for a processor running in big-endian mode; the default is
-to compile code for a little-endian processor.
-.Ip "\fB\-mwords-little-endian\fR" 4
-.IX Item "-mwords-little-endian"
-This option only applies when generating code for big-endian processors.
-Generate code for a little-endian word order but a big-endian byte
-order. That is, a byte order of the form \fB32107654\fR. Note: this
-option should only be used if you require compatibility with code for
-big-endian \s-1ARM\s0 processors generated by versions of the compiler prior to
-2.8.
-.Ip "\fB\-malignment-traps\fR" 4
-.IX Item "-malignment-traps"
-Generate code that will not trap if the \s-1MMU\s0 has alignment traps enabled.
-On \s-1ARM\s0 architectures prior to ARMv4, there were no instructions to
-access half-word objects stored in memory. However, when reading from
-memory a feature of the \s-1ARM\s0 architecture allows a word load to be used,
-even if the address is unaligned, and the processor core will rotate the
-data as it is being loaded. This option tells the compiler that such
-misaligned accesses will cause a \s-1MMU\s0 trap and that it should instead
-synthesise the access as a series of byte accesses. The compiler can
-still use word accesses to load half-word data if it knows that the
-address is aligned to a word boundary.
-.Sp
-This option is ignored when compiling for \s-1ARM\s0 architecture 4 or later,
-since these processors have instructions to directly access half-word
-objects in memory.
-.Ip "\fB\-mno-alignment-traps\fR" 4
-.IX Item "-mno-alignment-traps"
-Generate code that assumes that the \s-1MMU\s0 will not trap unaligned
-accesses. This produces better code when the target instruction set
-does not have half-word memory operations (i.e. implementations prior to
-ARMv4).
-.Sp
-Note that you cannot use this option to access unaligned word objects,
-since the processor will only fetch one 32\-bit aligned object from
-memory.
-.Sp
-The default setting for most targets is \fB\-mno-alignment-traps\fR, since
-this produces better code when there are no half-word memory
-instructions available.
-.Ip "\fB\-mshort-load-bytes\fR" 4
-.IX Item "-mshort-load-bytes"
-.PD 0
-.Ip "\fB\-mno-short-load-words\fR" 4
-.IX Item "-mno-short-load-words"
-.PD
-These are deprecated aliases for \fB\-malignment-traps\fR.
-.Ip "\fB\-mno-short-load-bytes\fR" 4
-.IX Item "-mno-short-load-bytes"
-.PD 0
-.Ip "\fB\-mshort-load-words\fR" 4
-.IX Item "-mshort-load-words"
-.PD
-This are deprecated aliases for \fB\-mno-alignment-traps\fR.
-.Ip "\fB\-mbsd\fR" 4
-.IX Item "-mbsd"
-This option only applies to \s-1RISC\s0 iX. Emulate the native BSD-mode
-compiler. This is the default if \fB\-ansi\fR is not specified.
-.Ip "\fB\-mxopen\fR" 4
-.IX Item "-mxopen"
-This option only applies to \s-1RISC\s0 iX. Emulate the native X/Open-mode
-compiler.
-.Ip "\fB\-mno-symrename\fR" 4
-.IX Item "-mno-symrename"
-This option only applies to \s-1RISC\s0 iX. Do not run the assembler
-post-processor, \fBsymrename\fR, after code has been assembled.
-Normally it is necessary to modify some of the standard symbols in
-preparation for linking with the \s-1RISC\s0 iX C library; this option
-suppresses this pass. The post-processor is never run when the
-compiler is built for cross-compilation.
-.Ip "\fB\-mcpu=\fR\fIname\fR" 4
-.IX Item "-mcpu=name"
-This specifies the name of the target \s-1ARM\s0 processor. \s-1GCC\s0 uses this name
-to determine what kind of instructions it can emit when generating
-assembly code. Permissible names are: arm2, arm250, arm3, arm6, arm60,
-arm600, arm610, arm620, arm7, arm7m, arm7d, arm7dm, arm7di, arm7dmi,
-arm70, arm700, arm700i, arm710, arm710c, arm7100, arm7500, arm7500fe,
-arm7tdmi, arm8, strongarm, strongarm110, strongarm1100, arm8, arm810,
-arm9, arm9e, arm920, arm920t, arm940t, arm9tdmi, arm10tdmi, arm1020t,
-xscale.
-.Ip "\fB\-mtune=\fR\fIname\fR" 4
-.IX Item "-mtune=name"
-This option is very similar to the \fB\-mcpu=\fR option, except that
-instead of specifying the actual target processor type, and hence
-restricting which instructions can be used, it specifies that \s-1GCC\s0 should
-tune the performance of the code as if the target were of the type
-specified in this option, but still choosing the instructions that it
-will generate based on the cpu specified by a \fB\-mcpu=\fR option.
-For some \s-1ARM\s0 implementations better performance can be obtained by using
-this option.
-.Ip "\fB\-march=\fR\fIname\fR" 4
-.IX Item "-march=name"
-This specifies the name of the target \s-1ARM\s0 architecture. \s-1GCC\s0 uses this
-name to determine what kind of instructions it can emit when generating
-assembly code. This option can be used in conjunction with or instead
-of the \fB\-mcpu=\fR option. Permissible names are: armv2, armv2a,
-armv3, armv3m, armv4, armv4t, armv5, armv5t, armv5te.
-.Ip "\fB\-mfpe=\fR\fInumber\fR" 4
-.IX Item "-mfpe=number"
-.PD 0
-.Ip "\fB\-mfp=\fR\fInumber\fR" 4
-.IX Item "-mfp=number"
-.PD
-This specifies the version of the floating point emulation available on
-the target. Permissible values are 2 and 3. \fB\-mfp=\fR is a synonym
-for \fB\-mfpe=\fR, for compatibility with older versions of \s-1GCC\s0.
-.Ip "\fB\-mstructure-size-boundary=\fR\fIn\fR" 4
-.IX Item "-mstructure-size-boundary=n"
-The size of all structures and unions will be rounded up to a multiple
-of the number of bits set by this option. Permissible values are 8 and
-32. The default value varies for different toolchains. For the \s-1COFF\s0
-targeted toolchain the default value is 8. Specifying the larger number
-can produce faster, more efficient code, but can also increase the size
-of the program. The two values are potentially incompatible. Code
-compiled with one value cannot necessarily expect to work with code or
-libraries compiled with the other value, if they exchange information
-using structures or unions.
-.Ip "\fB\-mabort-on-noreturn\fR" 4
-.IX Item "-mabort-on-noreturn"
-Generate a call to the function \f(CW\*(C`abort\*(C'\fR at the end of a
-\&\f(CW\*(C`noreturn\*(C'\fR function. It will be executed if the function tries to
-return.
-.Ip "\fB\-mlong-calls\fR" 4
-.IX Item "-mlong-calls"
-.PD 0
-.Ip "\fB\-mno-long-calls\fR" 4
-.IX Item "-mno-long-calls"
-.PD
-Tells the compiler to perform function calls by first loading the
-address of the function into a register and then performing a subroutine
-call on this register. This switch is needed if the target function
-will lie outside of the 64 megabyte addressing range of the offset based
-version of subroutine call instruction.
-.Sp
-Even if this switch is enabled, not all function calls will be turned
-into long calls. The heuristic is that static functions, functions
-which have the \fBshort-call\fR attribute, functions that are inside
-the scope of a \fB#pragma no_long_calls\fR directive and functions whose
-definitions have already been compiled within the current compilation
-unit, will not be turned into long calls. The exception to this rule is
-that weak function definitions, functions with the \fBlong-call\fR
-attribute or the \fBsection\fR attribute, and functions that are within
-the scope of a \fB#pragma long_calls\fR directive, will always be
-turned into long calls.
-.Sp
-This feature is not enabled by default. Specifying
-\&\fB\-mno-long-calls\fR will restore the default behaviour, as will
-placing the function calls within the scope of a \fB#pragma
-long_calls_off\fR directive. Note these switches have no effect on how
-the compiler generates code to handle function calls via function
-pointers.
-.Ip "\fB\-mnop-fun-dllimport\fR" 4
-.IX Item "-mnop-fun-dllimport"
-Disable support for the \fIdllimport\fR attribute.
-.Ip "\fB\-msingle-pic-base\fR" 4
-.IX Item "-msingle-pic-base"
-Treat the register used for \s-1PIC\s0 addressing as read-only, rather than
-loading it in the prologue for each function. The run-time system is
-responsible for initialising this register with an appropriate value
-before execution begins.
-.Ip "\fB\-mpic-register=\fR\fIreg\fR" 4
-.IX Item "-mpic-register=reg"
-Specify the register to be used for \s-1PIC\s0 addressing. The default is R10
-unless stack-checking is enabled, when R9 is used.
-.Ip "\fB\-mpoke-function-name\fR" 4
-.IX Item "-mpoke-function-name"
-Write the name of each function into the text section, directly
-preceding the function prologue. The generated code is similar to this:
-.Sp
-.Vb 9
-\& t0
-\& .ascii "arm_poke_function_name", 0
-\& .align
-\& t1
-\& .word 0xff000000 + (t1 - t0)
-\& arm_poke_function_name
-\& mov ip, sp
-\& stmfd sp!, {fp, ip, lr, pc}
-\& sub fp, ip, #4
-.Ve
-When performing a stack backtrace, code can inspect the value of
-\&\f(CW\*(C`pc\*(C'\fR stored at \f(CW\*(C`fp + 0\*(C'\fR. If the trace function then looks at
-location \f(CW\*(C`pc \- 12\*(C'\fR and the top 8 bits are set, then we know that
-there is a function name embedded immediately preceding this location
-and has length \f(CW\*(C`((pc[\-3]) & 0xff000000)\*(C'\fR.
-.Ip "\fB\-mthumb\fR" 4
-.IX Item "-mthumb"
-Generate code for the 16\-bit Thumb instruction set. The default is to
-use the 32\-bit \s-1ARM\s0 instruction set.
-.Ip "\fB\-mtpcs-frame\fR" 4
-.IX Item "-mtpcs-frame"
-Generate a stack frame that is compliant with the Thumb Procedure Call
-Standard for all non-leaf functions. (A leaf function is one that does
-not call any other functions.) The default is \fB\-mno-tpcs-frame\fR.
-.Ip "\fB\-mtpcs-leaf-frame\fR" 4
-.IX Item "-mtpcs-leaf-frame"
-Generate a stack frame that is compliant with the Thumb Procedure Call
-Standard for all leaf functions. (A leaf function is one that does
-not call any other functions.) The default is \fB\-mno-apcs-leaf-frame\fR.
-.Ip "\fB\-mcallee-super-interworking\fR" 4
-.IX Item "-mcallee-super-interworking"
-Gives all externally visible functions in the file being compiled an \s-1ARM\s0
-instruction set header which switches to Thumb mode before executing the
-rest of the function. This allows these functions to be called from
-non-interworking code.
-.Ip "\fB\-mcaller-super-interworking\fR" 4
-.IX Item "-mcaller-super-interworking"
-Allows calls via function pointers (including virtual functions) to
-execute correctly regardless of whether the target code has been
-compiled for interworking or not. There is a small overhead in the cost
-of executing a function pointer if this option is enabled.
-.PP
-.I "\s-1MN10200\s0 Options"
-.IX Subsection "MN10200 Options"
-.PP
-These \fB\-m\fR options are defined for Matsushita \s-1MN10200\s0 architectures:
-.Ip "\fB\-mrelax\fR" 4
-.IX Item "-mrelax"
-Indicate to the linker that it should perform a relaxation optimization pass
-to shorten branches, calls and absolute memory addresses. This option only
-has an effect when used on the command line for the final link step.
-.Sp
-This option makes symbolic debugging impossible.
-.PP
-.I "\s-1MN10300\s0 Options"
-.IX Subsection "MN10300 Options"
-.PP
-These \fB\-m\fR options are defined for Matsushita \s-1MN10300\s0 architectures:
-.Ip "\fB\-mmult-bug\fR" 4
-.IX Item "-mmult-bug"
-Generate code to avoid bugs in the multiply instructions for the \s-1MN10300\s0
-processors. This is the default.
-.Ip "\fB\-mno-mult-bug\fR" 4
-.IX Item "-mno-mult-bug"
-Do not generate code to avoid bugs in the multiply instructions for the
-\&\s-1MN10300\s0 processors.
-.Ip "\fB\-mam33\fR" 4
-.IX Item "-mam33"
-Generate code which uses features specific to the \s-1AM33\s0 processor.
-.Ip "\fB\-mno-am33\fR" 4
-.IX Item "-mno-am33"
-Do not generate code which uses features specific to the \s-1AM33\s0 processor. This
-is the default.
-.Ip "\fB\-mno-crt0\fR" 4
-.IX Item "-mno-crt0"
-Do not link in the C run-time initialization object file.
-.Ip "\fB\-mrelax\fR" 4
-.IX Item "-mrelax"
-Indicate to the linker that it should perform a relaxation optimization pass
-to shorten branches, calls and absolute memory addresses. This option only
-has an effect when used on the command line for the final link step.
-.Sp
-This option makes symbolic debugging impossible.
-.PP
-.I "M32R/D Options"
-.IX Subsection "M32R/D Options"
-.PP
-These \fB\-m\fR options are defined for Mitsubishi M32R/D architectures:
-.Ip "\fB\-mcode-model=small\fR" 4
-.IX Item "-mcode-model=small"
-Assume all objects live in the lower 16MB of memory (so that their addresses
-can be loaded with the \f(CW\*(C`ld24\*(C'\fR instruction), and assume all subroutines
-are reachable with the \f(CW\*(C`bl\*(C'\fR instruction.
-This is the default.
-.Sp
-The addressability of a particular object can be set with the
-\&\f(CW\*(C`model\*(C'\fR attribute.
-.Ip "\fB\-mcode-model=medium\fR" 4
-.IX Item "-mcode-model=medium"
-Assume objects may be anywhere in the 32\-bit address space (the compiler
-will generate \f(CW\*(C`seth/add3\*(C'\fR instructions to load their addresses), and
-assume all subroutines are reachable with the \f(CW\*(C`bl\*(C'\fR instruction.
-.Ip "\fB\-mcode-model=large\fR" 4
-.IX Item "-mcode-model=large"
-Assume objects may be anywhere in the 32\-bit address space (the compiler
-will generate \f(CW\*(C`seth/add3\*(C'\fR instructions to load their addresses), and
-assume subroutines may not be reachable with the \f(CW\*(C`bl\*(C'\fR instruction
-(the compiler will generate the much slower \f(CW\*(C`seth/add3/jl\*(C'\fR
-instruction sequence).
-.Ip "\fB\-msdata=none\fR" 4
-.IX Item "-msdata=none"
-Disable use of the small data area. Variables will be put into
-one of \fB.data\fR, \fBbss\fR, or \fB.rodata\fR (unless the
-\&\f(CW\*(C`section\*(C'\fR attribute has been specified).
-This is the default.
-.Sp
-The small data area consists of sections \fB.sdata\fR and \fB.sbss\fR.
-Objects may be explicitly put in the small data area with the
-\&\f(CW\*(C`section\*(C'\fR attribute using one of these sections.
-.Ip "\fB\-msdata=sdata\fR" 4
-.IX Item "-msdata=sdata"
-Put small global and static data in the small data area, but do not
-generate special code to reference them.
-.Ip "\fB\-msdata=use\fR" 4
-.IX Item "-msdata=use"
-Put small global and static data in the small data area, and generate
-special instructions to reference them.
-.Ip "\fB\-G\fR \fInum\fR" 4
-.IX Item "-G num"
-Put global and static objects less than or equal to \fInum\fR bytes
-into the small data or bss sections instead of the normal data or bss
-sections. The default value of \fInum\fR is 8.
-The \fB\-msdata\fR option must be set to one of \fBsdata\fR or \fBuse\fR
-for this option to have any effect.
-.Sp
-All modules should be compiled with the same \fB\-G\fR \fInum\fR value.
-Compiling with different values of \fInum\fR may or may not work; if it
-doesn't the linker will give an error message\-\-\-incorrect code will not be
-generated.
-.PP
-.I "M88K Options"
-.IX Subsection "M88K Options"
-.PP
-These \fB\-m\fR options are defined for Motorola 88k architectures:
-.Ip "\fB\-m88000\fR" 4
-.IX Item "-m88000"
-Generate code that works well on both the m88100 and the
-m88110.
-.Ip "\fB\-m88100\fR" 4
-.IX Item "-m88100"
-Generate code that works best for the m88100, but that also
-runs on the m88110.
-.Ip "\fB\-m88110\fR" 4
-.IX Item "-m88110"
-Generate code that works best for the m88110, and may not run
-on the m88100.
-.Ip "\fB\-mbig-pic\fR" 4
-.IX Item "-mbig-pic"
-Obsolete option to be removed from the next revision.
-Use \fB\-fPIC\fR.
-.Ip "\fB\-midentify-revision\fR" 4
-.IX Item "-midentify-revision"
-Include an \f(CW\*(C`ident\*(C'\fR directive in the assembler output recording the
-source file name, compiler name and version, timestamp, and compilation
-flags used.
-.Ip "\fB\-mno-underscores\fR" 4
-.IX Item "-mno-underscores"
-In assembler output, emit symbol names without adding an underscore
-character at the beginning of each name. The default is to use an
-underscore as prefix on each name.
-.Ip "\fB\-mocs-debug-info\fR" 4
-.IX Item "-mocs-debug-info"
-.PD 0
-.Ip "\fB\-mno-ocs-debug-info\fR" 4
-.IX Item "-mno-ocs-debug-info"
-.PD
-Include (or omit) additional debugging information (about registers used
-in each stack frame) as specified in the 88open Object Compatibility
-Standard, ``\s-1OCS\s0''. This extra information allows debugging of code that
-has had the frame pointer eliminated. The default for \s-1DG/UX\s0, SVr4, and
-Delta 88 SVr3.2 is to include this information; other 88k configurations
-omit this information by default.
-.Ip "\fB\-mocs-frame-position\fR" 4
-.IX Item "-mocs-frame-position"
-When emitting \s-1COFF\s0 debugging information for automatic variables and
-parameters stored on the stack, use the offset from the canonical frame
-address, which is the stack pointer (register 31) on entry to the
-function. The \s-1DG/UX\s0, SVr4, Delta88 SVr3.2, and \s-1BCS\s0 configurations use
-\&\fB\-mocs-frame-position\fR; other 88k configurations have the default
-\&\fB\-mno-ocs-frame-position\fR.
-.Ip "\fB\-mno-ocs-frame-position\fR" 4
-.IX Item "-mno-ocs-frame-position"
-When emitting \s-1COFF\s0 debugging information for automatic variables and
-parameters stored on the stack, use the offset from the frame pointer
-register (register 30). When this option is in effect, the frame
-pointer is not eliminated when debugging information is selected by the
-\&\-g switch.
-.Ip "\fB\-moptimize-arg-area\fR" 4
-.IX Item "-moptimize-arg-area"
-.PD 0
-.Ip "\fB\-mno-optimize-arg-area\fR" 4
-.IX Item "-mno-optimize-arg-area"
-.PD
-Control how function arguments are stored in stack frames.
-\&\fB\-moptimize-arg-area\fR saves space by optimizing them, but this
-conflicts with the 88open specifications. The opposite alternative,
-\&\fB\-mno-optimize-arg-area\fR, agrees with 88open standards. By default
-\&\s-1GCC\s0 does not optimize the argument area.
-.Ip "\fB\-mshort-data-\fR\fInum\fR" 4
-.IX Item "-mshort-data-num"
-Generate smaller data references by making them relative to \f(CW\*(C`r0\*(C'\fR,
-which allows loading a value using a single instruction (rather than the
-usual two). You control which data references are affected by
-specifying \fInum\fR with this option. For example, if you specify
-\&\fB\-mshort-data-512\fR, then the data references affected are those
-involving displacements of less than 512 bytes.
-\&\fB\-mshort-data-\fR\fInum\fR is not effective for \fInum\fR greater
-than 64k.
-.Ip "\fB\-mserialize-volatile\fR" 4
-.IX Item "-mserialize-volatile"
-.PD 0
-.Ip "\fB\-mno-serialize-volatile\fR" 4
-.IX Item "-mno-serialize-volatile"
-.PD
-Do, or don't, generate code to guarantee sequential consistency
-of volatile memory references. By default, consistency is
-guaranteed.
-.Sp
-The order of memory references made by the \s-1MC88110\s0 processor does
-not always match the order of the instructions requesting those
-references. In particular, a load instruction may execute before
-a preceding store instruction. Such reordering violates
-sequential consistency of volatile memory references, when there
-are multiple processors. When consistency must be guaranteed,
-\&\s-1GCC\s0 generates special instructions, as needed, to force
-execution in the proper order.
-.Sp
-The \s-1MC88100\s0 processor does not reorder memory references and so
-always provides sequential consistency. However, by default, \s-1GCC\s0
-generates the special instructions to guarantee consistency
-even when you use \fB\-m88100\fR, so that the code may be run on an
-\&\s-1MC88110\s0 processor. If you intend to run your code only on the
-\&\s-1MC88100\s0 processor, you may use \fB\-mno-serialize-volatile\fR.
-.Sp
-The extra code generated to guarantee consistency may affect the
-performance of your application. If you know that you can safely
-forgo this guarantee, you may use \fB\-mno-serialize-volatile\fR.
-.Ip "\fB\-msvr4\fR" 4
-.IX Item "-msvr4"
-.PD 0
-.Ip "\fB\-msvr3\fR" 4
-.IX Item "-msvr3"
-.PD
-Turn on (\fB\-msvr4\fR) or off (\fB\-msvr3\fR) compiler extensions
-related to System V release 4 (SVr4). This controls the following:
-.RS 4
-.Ip "1." 4
-Which variant of the assembler syntax to emit.
-.Ip "2." 4
-\&\fB\-msvr4\fR makes the C preprocessor recognize \fB#pragma weak\fR
-that is used on System V release 4.
-.Ip "3." 4
-\&\fB\-msvr4\fR makes \s-1GCC\s0 issue additional declaration directives used in
-SVr4.
-.RE
-.RS 4
-.Sp
-\&\fB\-msvr4\fR is the default for the m88k-motorola-sysv4 and
-m88k-dg-dgux m88k configurations. \fB\-msvr3\fR is the default for all
-other m88k configurations.
-.RE
-.Ip "\fB\-mversion-03.00\fR" 4
-.IX Item "-mversion-03.00"
-This option is obsolete, and is ignored.
-.Ip "\fB\-mno-check-zero-division\fR" 4
-.IX Item "-mno-check-zero-division"
-.PD 0
-.Ip "\fB\-mcheck-zero-division\fR" 4
-.IX Item "-mcheck-zero-division"
-.PD
-Do, or don't, generate code to guarantee that integer division by
-zero will be detected. By default, detection is guaranteed.
-.Sp
-Some models of the \s-1MC88100\s0 processor fail to trap upon integer
-division by zero under certain conditions. By default, when
-compiling code that might be run on such a processor, \s-1GCC\s0
-generates code that explicitly checks for zero-valued divisors
-and traps with exception number 503 when one is detected. Use of
-mno-check-zero-division suppresses such checking for code
-generated to run on an \s-1MC88100\s0 processor.
-.Sp
-\&\s-1GCC\s0 assumes that the \s-1MC88110\s0 processor correctly detects all
-instances of integer division by zero. When \fB\-m88110\fR is
-specified, both \fB\-mcheck-zero-division\fR and
-\&\fB\-mno-check-zero-division\fR are ignored, and no explicit checks for
-zero-valued divisors are generated.
-.Ip "\fB\-muse-div-instruction\fR" 4
-.IX Item "-muse-div-instruction"
-Use the div instruction for signed integer division on the
-\&\s-1MC88100\s0 processor. By default, the div instruction is not used.
-.Sp
-On the \s-1MC88100\s0 processor the signed integer division instruction
-div) traps to the operating system on a negative operand. The
-operating system transparently completes the operation, but at a
-large cost in execution time. By default, when compiling code
-that might be run on an \s-1MC88100\s0 processor, \s-1GCC\s0 emulates signed
-integer division using the unsigned integer division instruction
-divu), thereby avoiding the large penalty of a trap to the
-operating system. Such emulation has its own, smaller, execution
-cost in both time and space. To the extent that your code's
-important signed integer division operations are performed on two
-nonnegative operands, it may be desirable to use the div
-instruction directly.
-.Sp
-On the \s-1MC88110\s0 processor the div instruction (also known as the
-divs instruction) processes negative operands without trapping to
-the operating system. When \fB\-m88110\fR is specified,
-\&\fB\-muse-div-instruction\fR is ignored, and the div instruction is used
-for signed integer division.
-.Sp
-Note that the result of dividing \f(CW\*(C`INT_MIN\*(C'\fR by \-1 is undefined. In
-particular, the behavior of such a division with and without
-\&\fB\-muse-div-instruction\fR may differ.
-.Ip "\fB\-mtrap-large-shift\fR" 4
-.IX Item "-mtrap-large-shift"
-.PD 0
-.Ip "\fB\-mhandle-large-shift\fR" 4
-.IX Item "-mhandle-large-shift"
-.PD
-Include code to detect bit-shifts of more than 31 bits; respectively,
-trap such shifts or emit code to handle them properly. By default \s-1GCC\s0
-makes no special provision for large bit shifts.
-.Ip "\fB\-mwarn-passed-structs\fR" 4
-.IX Item "-mwarn-passed-structs"
-Warn when a function passes a struct as an argument or result.
-Structure-passing conventions have changed during the evolution of the C
-language, and are often the source of portability problems. By default,
-\&\s-1GCC\s0 issues no such warning.
-.PP
-.I "\s-1IBM\s0 \s-1RS/6000\s0 and PowerPC Options"
-.IX Subsection "IBM RS/6000 and PowerPC Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1IBM\s0 \s-1RS/6000\s0 and PowerPC:
-.Ip "\fB\-mpower\fR" 4
-.IX Item "-mpower"
-.PD 0
-.Ip "\fB\-mno-power\fR" 4
-.IX Item "-mno-power"
-.Ip "\fB\-mpower2\fR" 4
-.IX Item "-mpower2"
-.Ip "\fB\-mno-power2\fR" 4
-.IX Item "-mno-power2"
-.Ip "\fB\-mpowerpc\fR" 4
-.IX Item "-mpowerpc"
-.Ip "\fB\-mno-powerpc\fR" 4
-.IX Item "-mno-powerpc"
-.Ip "\fB\-mpowerpc-gpopt\fR" 4
-.IX Item "-mpowerpc-gpopt"
-.Ip "\fB\-mno-powerpc-gpopt\fR" 4
-.IX Item "-mno-powerpc-gpopt"
-.Ip "\fB\-mpowerpc-gfxopt\fR" 4
-.IX Item "-mpowerpc-gfxopt"
-.Ip "\fB\-mno-powerpc-gfxopt\fR" 4
-.IX Item "-mno-powerpc-gfxopt"
-.Ip "\fB\-mpowerpc64\fR" 4
-.IX Item "-mpowerpc64"
-.Ip "\fB\-mno-powerpc64\fR" 4
-.IX Item "-mno-powerpc64"
-.PD
-\&\s-1GCC\s0 supports two related instruction set architectures for the
-\&\s-1RS/6000\s0 and PowerPC. The \fI\s-1POWER\s0\fR instruction set are those
-instructions supported by the \fBrios\fR chip set used in the original
-\&\s-1RS/6000\s0 systems and the \fIPowerPC\fR instruction set is the
-architecture of the Motorola MPC5xx, MPC6xx, MPC8xx microprocessors, and
-the \s-1IBM\s0 4xx microprocessors.
-.Sp
-Neither architecture is a subset of the other. However there is a
-large common subset of instructions supported by both. An \s-1MQ\s0
-register is included in processors supporting the \s-1POWER\s0 architecture.
-.Sp
-You use these options to specify which instructions are available on the
-processor you are using. The default value of these options is
-determined when configuring \s-1GCC\s0. Specifying the
-\&\fB\-mcpu=\fR\fIcpu_type\fR overrides the specification of these
-options. We recommend you use the \fB\-mcpu=\fR\fIcpu_type\fR option
-rather than the options listed above.
-.Sp
-The \fB\-mpower\fR option allows \s-1GCC\s0 to generate instructions that
-are found only in the \s-1POWER\s0 architecture and to use the \s-1MQ\s0 register.
-Specifying \fB\-mpower2\fR implies \fB\-power\fR and also allows \s-1GCC\s0
-to generate instructions that are present in the \s-1POWER2\s0 architecture but
-not the original \s-1POWER\s0 architecture.
-.Sp
-The \fB\-mpowerpc\fR option allows \s-1GCC\s0 to generate instructions that
-are found only in the 32\-bit subset of the PowerPC architecture.
-Specifying \fB\-mpowerpc-gpopt\fR implies \fB\-mpowerpc\fR and also allows
-\&\s-1GCC\s0 to use the optional PowerPC architecture instructions in the
-General Purpose group, including floating-point square root. Specifying
-\&\fB\-mpowerpc-gfxopt\fR implies \fB\-mpowerpc\fR and also allows \s-1GCC\s0 to
-use the optional PowerPC architecture instructions in the Graphics
-group, including floating-point select.
-.Sp
-The \fB\-mpowerpc64\fR option allows \s-1GCC\s0 to generate the additional
-64\-bit instructions that are found in the full PowerPC64 architecture
-and to treat GPRs as 64\-bit, doubleword quantities. \s-1GCC\s0 defaults to
-\&\fB\-mno-powerpc64\fR.
-.Sp
-If you specify both \fB\-mno-power\fR and \fB\-mno-powerpc\fR, \s-1GCC\s0
-will use only the instructions in the common subset of both
-architectures plus some special \s-1AIX\s0 common-mode calls, and will not use
-the \s-1MQ\s0 register. Specifying both \fB\-mpower\fR and \fB\-mpowerpc\fR
-permits \s-1GCC\s0 to use any instruction from either architecture and to
-allow use of the \s-1MQ\s0 register; specify this for the Motorola \s-1MPC601\s0.
-.Ip "\fB\-mnew-mnemonics\fR" 4
-.IX Item "-mnew-mnemonics"
-.PD 0
-.Ip "\fB\-mold-mnemonics\fR" 4
-.IX Item "-mold-mnemonics"
-.PD
-Select which mnemonics to use in the generated assembler code.
-\&\fB\-mnew-mnemonics\fR requests output that uses the assembler mnemonics
-defined for the PowerPC architecture, while \fB\-mold-mnemonics\fR
-requests the assembler mnemonics defined for the \s-1POWER\s0 architecture.
-Instructions defined in only one architecture have only one mnemonic;
-\&\s-1GCC\s0 uses that mnemonic irrespective of which of these options is
-specified.
-.Sp
-\&\s-1GCC\s0 defaults to the mnemonics appropriate for the architecture in
-use. Specifying \fB\-mcpu=\fR\fIcpu_type\fR sometimes overrides the
-value of these option. Unless you are building a cross-compiler, you
-should normally not specify either \fB\-mnew-mnemonics\fR or
-\&\fB\-mold-mnemonics\fR, but should instead accept the default.
-.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4
-.IX Item "-mcpu=cpu_type"
-Set architecture type, register usage, choice of mnemonics, and
-instruction scheduling parameters for machine type \fIcpu_type\fR.
-Supported values for \fIcpu_type\fR are \fBrios\fR, \fBrios1\fR,
-\&\fBrsc\fR, \fBrios2\fR, \fBrs64a\fR, \fB601\fR, \fB602\fR,
-\&\fB603\fR, \fB603e\fR, \fB604\fR, \fB604e\fR, \fB620\fR,
-\&\fB630\fR, \fB740\fR, \fB750\fR, \fBpower\fR, \fBpower2\fR,
-\&\fBpowerpc\fR, \fB403\fR, \fB505\fR, \fB801\fR, \fB821\fR,
-\&\fB823\fR, and \fB860\fR and \fBcommon\fR. \fB\-mcpu=power\fR,
-\&\fB\-mcpu=power2\fR, \fB\-mcpu=powerpc\fR, and \fB\-mcpu=powerpc64\fR
-specify generic \s-1POWER\s0, \s-1POWER2\s0, pure 32\-bit PowerPC (i.e., not \s-1MPC601\s0),
-and 64\-bit PowerPC architecture machine types, with an appropriate,
-generic processor model assumed for scheduling purposes.
-.Sp
-Specifying any of the following options:
-\&\fB\-mcpu=rios1\fR, \fB\-mcpu=rios2\fR, \fB\-mcpu=rsc\fR,
-\&\fB\-mcpu=power\fR, or \fB\-mcpu=power2\fR
-enables the \fB\-mpower\fR option and disables the \fB\-mpowerpc\fR option;
-\&\fB\-mcpu=601\fR enables both the \fB\-mpower\fR and \fB\-mpowerpc\fR options.
-All of \fB\-mcpu=rs64a\fR, \fB\-mcpu=602\fR, \fB\-mcpu=603\fR,
-\&\fB\-mcpu=603e\fR, \fB\-mcpu=604\fR, \fB\-mcpu=620\fR, \fB\-mcpu=630\fR,
-\&\fB\-mcpu=740\fR, and \fB\-mcpu=750\fR
-enable the \fB\-mpowerpc\fR option and disable the \fB\-mpower\fR option.
-Exactly similarly, all of \fB\-mcpu=403\fR,
-\&\fB\-mcpu=505\fR, \fB\-mcpu=821\fR, \fB\-mcpu=860\fR and \fB\-mcpu=powerpc\fR
-enable the \fB\-mpowerpc\fR option and disable the \fB\-mpower\fR option.
-\&\fB\-mcpu=common\fR disables both the
-\&\fB\-mpower\fR and \fB\-mpowerpc\fR options.
-.Sp
-\&\s-1AIX\s0 versions 4 or greater selects \fB\-mcpu=common\fR by default, so
-that code will operate on all members of the \s-1RS/6000\s0 \s-1POWER\s0 and PowerPC
-families. In that case, \s-1GCC\s0 will use only the instructions in the
-common subset of both architectures plus some special \s-1AIX\s0 common-mode
-calls, and will not use the \s-1MQ\s0 register. \s-1GCC\s0 assumes a generic
-processor model for scheduling purposes.
-.Sp
-Specifying any of the options \fB\-mcpu=rios1\fR, \fB\-mcpu=rios2\fR,
-\&\fB\-mcpu=rsc\fR, \fB\-mcpu=power\fR, or \fB\-mcpu=power2\fR also
-disables the \fBnew-mnemonics\fR option. Specifying \fB\-mcpu=601\fR,
-\&\fB\-mcpu=602\fR, \fB\-mcpu=603\fR, \fB\-mcpu=603e\fR, \fB\-mcpu=604\fR,
-\&\fB\-mcpu=620\fR, \fB\-mcpu=630\fR, \fB\-mcpu=403\fR, \fB\-mcpu=505\fR,
-\&\fB\-mcpu=821\fR, \fB\-mcpu=860\fR or \fB\-mcpu=powerpc\fR also enables
-the \fBnew-mnemonics\fR option.
-.Sp
-Specifying \fB\-mcpu=403\fR, \fB\-mcpu=821\fR, or \fB\-mcpu=860\fR also
-enables the \fB\-msoft-float\fR option.
-.Ip "\fB\-mtune=\fR\fIcpu_type\fR" 4
-.IX Item "-mtune=cpu_type"
-Set the instruction scheduling parameters for machine type
-\&\fIcpu_type\fR, but do not set the architecture type, register usage,
-choice of mnemonics like \fB\-mcpu=\fR\fIcpu_type\fR would. The same
-values for \fIcpu_type\fR are used for \fB\-mtune=\fR\fIcpu_type\fR as
-for \fB\-mcpu=\fR\fIcpu_type\fR. The \fB\-mtune=\fR\fIcpu_type\fR
-option overrides the \fB\-mcpu=\fR\fIcpu_type\fR option in terms of
-instruction scheduling parameters.
-.Ip "\fB\-mfull-toc\fR" 4
-.IX Item "-mfull-toc"
-.PD 0
-.Ip "\fB\-mno-fp-in-toc\fR" 4
-.IX Item "-mno-fp-in-toc"
-.Ip "\fB\-mno-sum-in-toc\fR" 4
-.IX Item "-mno-sum-in-toc"
-.Ip "\fB\-mminimal-toc\fR" 4
-.IX Item "-mminimal-toc"
-.PD
-Modify generation of the \s-1TOC\s0 (Table Of Contents), which is created for
-every executable file. The \fB\-mfull-toc\fR option is selected by
-default. In that case, \s-1GCC\s0 will allocate at least one \s-1TOC\s0 entry for
-each unique non-automatic variable reference in your program. \s-1GCC\s0
-will also place floating-point constants in the \s-1TOC\s0. However, only
-16,384 entries are available in the \s-1TOC\s0.
-.Sp
-If you receive a linker error message that saying you have overflowed
-the available \s-1TOC\s0 space, you can reduce the amount of \s-1TOC\s0 space used
-with the \fB\-mno-fp-in-toc\fR and \fB\-mno-sum-in-toc\fR options.
-\&\fB\-mno-fp-in-toc\fR prevents \s-1GCC\s0 from putting floating-point
-constants in the \s-1TOC\s0 and \fB\-mno-sum-in-toc\fR forces \s-1GCC\s0 to
-generate code to calculate the sum of an address and a constant at
-run-time instead of putting that sum into the \s-1TOC\s0. You may specify one
-or both of these options. Each causes \s-1GCC\s0 to produce very slightly
-slower and larger code at the expense of conserving \s-1TOC\s0 space.
-.Sp
-If you still run out of space in the \s-1TOC\s0 even when you specify both of
-these options, specify \fB\-mminimal-toc\fR instead. This option causes
-\&\s-1GCC\s0 to make only one \s-1TOC\s0 entry for every file. When you specify this
-option, \s-1GCC\s0 will produce code that is slower and larger but which
-uses extremely little \s-1TOC\s0 space. You may wish to use this option
-only on files that contain less frequently executed code.
-.Ip "\fB\-maix64\fR" 4
-.IX Item "-maix64"
-.PD 0
-.Ip "\fB\-maix32\fR" 4
-.IX Item "-maix32"
-.PD
-Enable 64\-bit \s-1AIX\s0 \s-1ABI\s0 and calling convention: 64\-bit pointers, 64\-bit
-\&\f(CW\*(C`long\*(C'\fR type, and the infrastructure needed to support them.
-Specifying \fB\-maix64\fR implies \fB\-mpowerpc64\fR and
-\&\fB\-mpowerpc\fR, while \fB\-maix32\fR disables the 64\-bit \s-1ABI\s0 and
-implies \fB\-mno-powerpc64\fR. \s-1GCC\s0 defaults to \fB\-maix32\fR.
-.Ip "\fB\-mxl-call\fR" 4
-.IX Item "-mxl-call"
-.PD 0
-.Ip "\fB\-mno-xl-call\fR" 4
-.IX Item "-mno-xl-call"
-.PD
-On \s-1AIX\s0, pass floating-point arguments to prototyped functions beyond the
-register save area (\s-1RSA\s0) on the stack in addition to argument FPRs. The
-\&\s-1AIX\s0 calling convention was extended but not initially documented to
-handle an obscure K&R C case of calling a function that takes the
-address of its arguments with fewer arguments than declared. \s-1AIX\s0 \s-1XL\s0
-compilers access floating point arguments which do not fit in the
-\&\s-1RSA\s0 from the stack when a subroutine is compiled without
-optimization. Because always storing floating-point arguments on the
-stack is inefficient and rarely needed, this option is not enabled by
-default and only is necessary when calling subroutines compiled by \s-1AIX\s0
-\&\s-1XL\s0 compilers without optimization.
-.Ip "\fB\-mthreads\fR" 4
-.IX Item "-mthreads"
-Support \fI\s-1AIX\s0 Threads\fR. Link an application written to use
-\&\fIpthreads\fR with special libraries and startup code to enable the
-application to run.
-.Ip "\fB\-mpe\fR" 4
-.IX Item "-mpe"
-Support \fI\s-1IBM\s0 \s-1RS/6000\s0 \s-1SP\s0\fR \fIParallel Environment\fR (\s-1PE\s0). Link an
-application written to use message passing with special startup code to
-enable the application to run. The system must have \s-1PE\s0 installed in the
-standard location (\fI/usr/lpp/ppe.poe/\fR), or the \fIspecs\fR file
-must be overridden with the \fB\-specs=\fR option to specify the
-appropriate directory location. The Parallel Environment does not
-support threads, so the \fB\-mpe\fR option and the \fB\-mthreads\fR
-option are incompatible.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-.PD 0
-.Ip "\fB\-mhard-float\fR" 4
-.IX Item "-mhard-float"
-.PD
-Generate code that does not use (uses) the floating-point register set.
-Software floating point emulation is provided if you use the
-\&\fB\-msoft-float\fR option, and pass the option to \s-1GCC\s0 when linking.
-.Ip "\fB\-mmultiple\fR" 4
-.IX Item "-mmultiple"
-.PD 0
-.Ip "\fB\-mno-multiple\fR" 4
-.IX Item "-mno-multiple"
-.PD
-Generate code that uses (does not use) the load multiple word
-instructions and the store multiple word instructions. These
-instructions are generated by default on \s-1POWER\s0 systems, and not
-generated on PowerPC systems. Do not use \fB\-mmultiple\fR on little
-endian PowerPC systems, since those instructions do not work when the
-processor is in little endian mode. The exceptions are \s-1PPC740\s0 and
-\&\s-1PPC750\s0 which permit the instructions usage in little endian mode.
-.Ip "\fB\-mstring\fR" 4
-.IX Item "-mstring"
-.PD 0
-.Ip "\fB\-mno-string\fR" 4
-.IX Item "-mno-string"
-.PD
-Generate code that uses (does not use) the load string instructions
-and the store string word instructions to save multiple registers and
-do small block moves. These instructions are generated by default on
-\&\s-1POWER\s0 systems, and not generated on PowerPC systems. Do not use
-\&\fB\-mstring\fR on little endian PowerPC systems, since those
-instructions do not work when the processor is in little endian mode.
-The exceptions are \s-1PPC740\s0 and \s-1PPC750\s0 which permit the instructions
-usage in little endian mode.
-.Ip "\fB\-mupdate\fR" 4
-.IX Item "-mupdate"
-.PD 0
-.Ip "\fB\-mno-update\fR" 4
-.IX Item "-mno-update"
-.PD
-Generate code that uses (does not use) the load or store instructions
-that update the base register to the address of the calculated memory
-location. These instructions are generated by default. If you use
-\&\fB\-mno-update\fR, there is a small window between the time that the
-stack pointer is updated and the address of the previous frame is
-stored, which means code that walks the stack frame across interrupts or
-signals may get corrupted data.
-.Ip "\fB\-mfused-madd\fR" 4
-.IX Item "-mfused-madd"
-.PD 0
-.Ip "\fB\-mno-fused-madd\fR" 4
-.IX Item "-mno-fused-madd"
-.PD
-Generate code that uses (does not use) the floating point multiply and
-accumulate instructions. These instructions are generated by default if
-hardware floating is used.
-.Ip "\fB\-mno-bit-align\fR" 4
-.IX Item "-mno-bit-align"
-.PD 0
-.Ip "\fB\-mbit-align\fR" 4
-.IX Item "-mbit-align"
-.PD
-On System V.4 and embedded PowerPC systems do not (do) force structures
-and unions that contain bit-fields to be aligned to the base type of the
-bit-field.
-.Sp
-For example, by default a structure containing nothing but 8
-\&\f(CW\*(C`unsigned\*(C'\fR bit-fields of length 1 would be aligned to a 4 byte
-boundary and have a size of 4 bytes. By using \fB\-mno-bit-align\fR,
-the structure would be aligned to a 1 byte boundary and be one byte in
-size.
-.Ip "\fB\-mno-strict-align\fR" 4
-.IX Item "-mno-strict-align"
-.PD 0
-.Ip "\fB\-mstrict-align\fR" 4
-.IX Item "-mstrict-align"
-.PD
-On System V.4 and embedded PowerPC systems do not (do) assume that
-unaligned memory references will be handled by the system.
-.Ip "\fB\-mrelocatable\fR" 4
-.IX Item "-mrelocatable"
-.PD 0
-.Ip "\fB\-mno-relocatable\fR" 4
-.IX Item "-mno-relocatable"
-.PD
-On embedded PowerPC systems generate code that allows (does not allow)
-the program to be relocated to a different address at runtime. If you
-use \fB\-mrelocatable\fR on any module, all objects linked together must
-be compiled with \fB\-mrelocatable\fR or \fB\-mrelocatable-lib\fR.
-.Ip "\fB\-mrelocatable-lib\fR" 4
-.IX Item "-mrelocatable-lib"
-.PD 0
-.Ip "\fB\-mno-relocatable-lib\fR" 4
-.IX Item "-mno-relocatable-lib"
-.PD
-On embedded PowerPC systems generate code that allows (does not allow)
-the program to be relocated to a different address at runtime. Modules
-compiled with \fB\-mrelocatable-lib\fR can be linked with either modules
-compiled without \fB\-mrelocatable\fR and \fB\-mrelocatable-lib\fR or
-with modules compiled with the \fB\-mrelocatable\fR options.
-.Ip "\fB\-mno-toc\fR" 4
-.IX Item "-mno-toc"
-.PD 0
-.Ip "\fB\-mtoc\fR" 4
-.IX Item "-mtoc"
-.PD
-On System V.4 and embedded PowerPC systems do not (do) assume that
-register 2 contains a pointer to a global area pointing to the addresses
-used in the program.
-.Ip "\fB\-mlittle\fR" 4
-.IX Item "-mlittle"
-.PD 0
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-.PD
-On System V.4 and embedded PowerPC systems compile code for the
-processor in little endian mode. The \fB\-mlittle-endian\fR option is
-the same as \fB\-mlittle\fR.
-.Ip "\fB\-mbig\fR" 4
-.IX Item "-mbig"
-.PD 0
-.Ip "\fB\-mbig-endian\fR" 4
-.IX Item "-mbig-endian"
-.PD
-On System V.4 and embedded PowerPC systems compile code for the
-processor in big endian mode. The \fB\-mbig-endian\fR option is
-the same as \fB\-mbig\fR.
-.Ip "\fB\-mcall-sysv\fR" 4
-.IX Item "-mcall-sysv"
-On System V.4 and embedded PowerPC systems compile code using calling
-conventions that adheres to the March 1995 draft of the System V
-Application Binary Interface, PowerPC processor supplement. This is the
-default unless you configured \s-1GCC\s0 using \fBpowerpc-*\-eabiaix\fR.
-.Ip "\fB\-mcall-sysv-eabi\fR" 4
-.IX Item "-mcall-sysv-eabi"
-Specify both \fB\-mcall-sysv\fR and \fB\-meabi\fR options.
-.Ip "\fB\-mcall-sysv-noeabi\fR" 4
-.IX Item "-mcall-sysv-noeabi"
-Specify both \fB\-mcall-sysv\fR and \fB\-mno-eabi\fR options.
-.Ip "\fB\-mcall-aix\fR" 4
-.IX Item "-mcall-aix"
-On System V.4 and embedded PowerPC systems compile code using calling
-conventions that are similar to those used on \s-1AIX\s0. This is the
-default if you configured \s-1GCC\s0 using \fBpowerpc-*\-eabiaix\fR.
-.Ip "\fB\-mcall-solaris\fR" 4
-.IX Item "-mcall-solaris"
-On System V.4 and embedded PowerPC systems compile code for the Solaris
-operating system.
-.Ip "\fB\-mcall-linux\fR" 4
-.IX Item "-mcall-linux"
-On System V.4 and embedded PowerPC systems compile code for the
-Linux-based \s-1GNU\s0 system.
-.Ip "\fB\-mprototype\fR" 4
-.IX Item "-mprototype"
-.PD 0
-.Ip "\fB\-mno-prototype\fR" 4
-.IX Item "-mno-prototype"
-.PD
-On System V.4 and embedded PowerPC systems assume that all calls to
-variable argument functions are properly prototyped. Otherwise, the
-compiler must insert an instruction before every non prototyped call to
-set or clear bit 6 of the condition code register (\fI\s-1CR\s0\fR) to
-indicate whether floating point values were passed in the floating point
-registers in case the function takes a variable arguments. With
-\&\fB\-mprototype\fR, only calls to prototyped variable argument functions
-will set or clear the bit.
-.Ip "\fB\-msim\fR" 4
-.IX Item "-msim"
-On embedded PowerPC systems, assume that the startup module is called
-\&\fIsim-crt0.o\fR and that the standard C libraries are \fIlibsim.a\fR and
-\&\fIlibc.a\fR. This is the default for \fBpowerpc-*\-eabisim\fR.
-configurations.
-.Ip "\fB\-mmvme\fR" 4
-.IX Item "-mmvme"
-On embedded PowerPC systems, assume that the startup module is called
-\&\fIcrt0.o\fR and the standard C libraries are \fIlibmvme.a\fR and
-\&\fIlibc.a\fR.
-.Ip "\fB\-mads\fR" 4
-.IX Item "-mads"
-On embedded PowerPC systems, assume that the startup module is called
-\&\fIcrt0.o\fR and the standard C libraries are \fIlibads.a\fR and
-\&\fIlibc.a\fR.
-.Ip "\fB\-myellowknife\fR" 4
-.IX Item "-myellowknife"
-On embedded PowerPC systems, assume that the startup module is called
-\&\fIcrt0.o\fR and the standard C libraries are \fIlibyk.a\fR and
-\&\fIlibc.a\fR.
-.Ip "\fB\-mvxworks\fR" 4
-.IX Item "-mvxworks"
-On System V.4 and embedded PowerPC systems, specify that you are
-compiling for a VxWorks system.
-.Ip "\fB\-memb\fR" 4
-.IX Item "-memb"
-On embedded PowerPC systems, set the \fI\s-1PPC_EMB\s0\fR bit in the \s-1ELF\s0 flags
-header to indicate that \fBeabi\fR extended relocations are used.
-.Ip "\fB\-meabi\fR" 4
-.IX Item "-meabi"
-.PD 0
-.Ip "\fB\-mno-eabi\fR" 4
-.IX Item "-mno-eabi"
-.PD
-On System V.4 and embedded PowerPC systems do (do not) adhere to the
-Embedded Applications Binary Interface (eabi) which is a set of
-modifications to the System V.4 specifications. Selecting \fB\-meabi\fR
-means that the stack is aligned to an 8 byte boundary, a function
-\&\f(CW\*(C`_\|_eabi\*(C'\fR is called to from \f(CW\*(C`main\*(C'\fR to set up the eabi
-environment, and the \fB\-msdata\fR option can use both \f(CW\*(C`r2\*(C'\fR and
-\&\f(CW\*(C`r13\*(C'\fR to point to two separate small data areas. Selecting
-\&\fB\-mno-eabi\fR means that the stack is aligned to a 16 byte boundary,
-do not call an initialization function from \f(CW\*(C`main\*(C'\fR, and the
-\&\fB\-msdata\fR option will only use \f(CW\*(C`r13\*(C'\fR to point to a single
-small data area. The \fB\-meabi\fR option is on by default if you
-configured \s-1GCC\s0 using one of the \fBpowerpc*\-*\-eabi*\fR options.
-.Ip "\fB\-msdata=eabi\fR" 4
-.IX Item "-msdata=eabi"
-On System V.4 and embedded PowerPC systems, put small initialized
-\&\f(CW\*(C`const\*(C'\fR global and static data in the \fB.sdata2\fR section, which
-is pointed to by register \f(CW\*(C`r2\*(C'\fR. Put small initialized
-non-\f(CW\*(C`const\*(C'\fR global and static data in the \fB.sdata\fR section,
-which is pointed to by register \f(CW\*(C`r13\*(C'\fR. Put small uninitialized
-global and static data in the \fB.sbss\fR section, which is adjacent to
-the \fB.sdata\fR section. The \fB\-msdata=eabi\fR option is
-incompatible with the \fB\-mrelocatable\fR option. The
-\&\fB\-msdata=eabi\fR option also sets the \fB\-memb\fR option.
-.Ip "\fB\-msdata=sysv\fR" 4
-.IX Item "-msdata=sysv"
-On System V.4 and embedded PowerPC systems, put small global and static
-data in the \fB.sdata\fR section, which is pointed to by register
-\&\f(CW\*(C`r13\*(C'\fR. Put small uninitialized global and static data in the
-\&\fB.sbss\fR section, which is adjacent to the \fB.sdata\fR section.
-The \fB\-msdata=sysv\fR option is incompatible with the
-\&\fB\-mrelocatable\fR option.
-.Ip "\fB\-msdata=default\fR" 4
-.IX Item "-msdata=default"
-.PD 0
-.Ip "\fB\-msdata\fR" 4
-.IX Item "-msdata"
-.PD
-On System V.4 and embedded PowerPC systems, if \fB\-meabi\fR is used,
-compile code the same as \fB\-msdata=eabi\fR, otherwise compile code the
-same as \fB\-msdata=sysv\fR.
-.Ip "\fB\-msdata-data\fR" 4
-.IX Item "-msdata-data"
-On System V.4 and embedded PowerPC systems, put small global and static
-data in the \fB.sdata\fR section. Put small uninitialized global and
-static data in the \fB.sbss\fR section. Do not use register \f(CW\*(C`r13\*(C'\fR
-to address small data however. This is the default behavior unless
-other \fB\-msdata\fR options are used.
-.Ip "\fB\-msdata=none\fR" 4
-.IX Item "-msdata=none"
-.PD 0
-.Ip "\fB\-mno-sdata\fR" 4
-.IX Item "-mno-sdata"
-.PD
-On embedded PowerPC systems, put all initialized global and static data
-in the \fB.data\fR section, and all uninitialized data in the
-\&\fB.bss\fR section.
-.Ip "\fB\-G\fR \fInum\fR" 4
-.IX Item "-G num"
-On embedded PowerPC systems, put global and static items less than or
-equal to \fInum\fR bytes into the small data or bss sections instead of
-the normal data or bss section. By default, \fInum\fR is 8. The
-\&\fB\-G\fR \fInum\fR switch is also passed to the linker.
-All modules should be compiled with the same \fB\-G\fR \fInum\fR value.
-.Ip "\fB\-mregnames\fR" 4
-.IX Item "-mregnames"
-.PD 0
-.Ip "\fB\-mno-regnames\fR" 4
-.IX Item "-mno-regnames"
-.PD
-On System V.4 and embedded PowerPC systems do (do not) emit register
-names in the assembly language output using symbolic forms.
-.PP
-.I "\s-1IBM\s0 \s-1RT\s0 Options"
-.IX Subsection "IBM RT Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1IBM\s0 \s-1RT\s0 \s-1PC:\s0
-.Ip "\fB\-min-line-mul\fR" 4
-.IX Item "-min-line-mul"
-Use an in-line code sequence for integer multiplies. This is the
-default.
-.Ip "\fB\-mcall-lib-mul\fR" 4
-.IX Item "-mcall-lib-mul"
-Call \f(CW\*(C`lmul$$\*(C'\fR for integer multiples.
-.Ip "\fB\-mfull-fp-blocks\fR" 4
-.IX Item "-mfull-fp-blocks"
-Generate full-size floating point data blocks, including the minimum
-amount of scratch space recommended by \s-1IBM\s0. This is the default.
-.Ip "\fB\-mminimum-fp-blocks\fR" 4
-.IX Item "-mminimum-fp-blocks"
-Do not include extra scratch space in floating point data blocks. This
-results in smaller code, but slower execution, since scratch space must
-be allocated dynamically.
-.Ip "\fB\-mfp-arg-in-fpregs\fR" 4
-.IX Item "-mfp-arg-in-fpregs"
-Use a calling sequence incompatible with the \s-1IBM\s0 calling convention in
-which floating point arguments are passed in floating point registers.
-Note that \f(CW\*(C`varargs.h\*(C'\fR and \f(CW\*(C`stdarg.h\*(C'\fR will not work with
-floating point operands if this option is specified.
-.Ip "\fB\-mfp-arg-in-gregs\fR" 4
-.IX Item "-mfp-arg-in-gregs"
-Use the normal calling convention for floating point arguments. This is
-the default.
-.Ip "\fB\-mhc-struct-return\fR" 4
-.IX Item "-mhc-struct-return"
-Return structures of more than one word in memory, rather than in a
-register. This provides compatibility with the MetaWare HighC (hc)
-compiler. Use the option \fB\-fpcc-struct-return\fR for compatibility
-with the Portable C Compiler (pcc).
-.Ip "\fB\-mnohc-struct-return\fR" 4
-.IX Item "-mnohc-struct-return"
-Return some structures of more than one word in registers, when
-convenient. This is the default. For compatibility with the
-IBM-supplied compilers, use the option \fB\-fpcc-struct-return\fR or the
-option \fB\-mhc-struct-return\fR.
-.PP
-.I "\s-1MIPS\s0 Options"
-.IX Subsection "MIPS Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1MIPS\s0 family of computers:
-.Ip "\fB\-mcpu=\fR\fIcpu-type\fR" 4
-.IX Item "-mcpu=cpu-type"
-Assume the defaults for the machine type \fIcpu-type\fR when scheduling
-instructions. The choices for \fIcpu-type\fR are \fBr2000\fR, \fBr3000\fR,
-\&\fBr3900\fR, \fBr4000\fR, \fBr4100\fR, \fBr4300\fR, \fBr4400\fR,
-\&\fBr4600\fR, \fBr4650\fR, \fBr5000\fR, \fBr6000\fR, \fBr8000\fR,
-and \fBorion\fR. Additionally, the \fBr2000\fR, \fBr3000\fR,
-\&\fBr4000\fR, \fBr5000\fR, and \fBr6000\fR can be abbreviated as
-\&\fBr2k\fR (or \fBr2K\fR), \fBr3k\fR, etc. While picking a specific
-\&\fIcpu-type\fR will schedule things appropriately for that particular
-chip, the compiler will not generate any code that does not meet level 1
-of the \s-1MIPS\s0 \s-1ISA\s0 (instruction set architecture) without a \fB\-mipsX\fR
-or \fB\-mabi\fR switch being used.
-.Ip "\fB\-mips1\fR" 4
-.IX Item "-mips1"
-Issue instructions from level 1 of the \s-1MIPS\s0 \s-1ISA\s0. This is the default.
-\&\fBr3000\fR is the default \fIcpu-type\fR at this \s-1ISA\s0 level.
-.Ip "\fB\-mips2\fR" 4
-.IX Item "-mips2"
-Issue instructions from level 2 of the \s-1MIPS\s0 \s-1ISA\s0 (branch likely, square
-root instructions). \fBr6000\fR is the default \fIcpu-type\fR at this
-\&\s-1ISA\s0 level.
-.Ip "\fB\-mips3\fR" 4
-.IX Item "-mips3"
-Issue instructions from level 3 of the \s-1MIPS\s0 \s-1ISA\s0 (64\-bit instructions).
-\&\fBr4000\fR is the default \fIcpu-type\fR at this \s-1ISA\s0 level.
-.Ip "\fB\-mips4\fR" 4
-.IX Item "-mips4"
-Issue instructions from level 4 of the \s-1MIPS\s0 \s-1ISA\s0 (conditional move,
-prefetch, enhanced \s-1FPU\s0 instructions). \fBr8000\fR is the default
-\&\fIcpu-type\fR at this \s-1ISA\s0 level.
-.Ip "\fB\-mfp32\fR" 4
-.IX Item "-mfp32"
-Assume that 32 32\-bit floating point registers are available. This is
-the default.
-.Ip "\fB\-mfp64\fR" 4
-.IX Item "-mfp64"
-Assume that 32 64\-bit floating point registers are available. This is
-the default when the \fB\-mips3\fR option is used.
-.Ip "\fB\-mgp32\fR" 4
-.IX Item "-mgp32"
-Assume that 32 32\-bit general purpose registers are available. This is
-the default.
-.Ip "\fB\-mgp64\fR" 4
-.IX Item "-mgp64"
-Assume that 32 64\-bit general purpose registers are available. This is
-the default when the \fB\-mips3\fR option is used.
-.Ip "\fB\-mint64\fR" 4
-.IX Item "-mint64"
-Force int and long types to be 64 bits wide. See \fB\-mlong32\fR for an
-explanation of the default, and the width of pointers.
-.Ip "\fB\-mlong64\fR" 4
-.IX Item "-mlong64"
-Force long types to be 64 bits wide. See \fB\-mlong32\fR for an
-explanation of the default, and the width of pointers.
-.Ip "\fB\-mlong32\fR" 4
-.IX Item "-mlong32"
-Force long, int, and pointer types to be 32 bits wide.
-.Sp
-If none of \fB\-mlong32\fR, \fB\-mlong64\fR, or \fB\-mint64\fR are set,
-the size of ints, longs, and pointers depends on the \s-1ABI\s0 and \s-1ISA\s0 chosen.
-For \fB\-mabi=32\fR, and \fB\-mabi=n32\fR, ints and longs are 32 bits
-wide. For \fB\-mabi=64\fR, ints are 32 bits, and longs are 64 bits wide.
-For \fB\-mabi=eabi\fR and either \fB\-mips1\fR or \fB\-mips2\fR, ints
-and longs are 32 bits wide. For \fB\-mabi=eabi\fR and higher ISAs, ints
-are 32 bits, and longs are 64 bits wide. The width of pointer types is
-the smaller of the width of longs or the width of general purpose
-registers (which in turn depends on the \s-1ISA\s0).
-.Ip "\fB\-mabi=32\fR" 4
-.IX Item "-mabi=32"
-.PD 0
-.Ip "\fB\-mabi=o64\fR" 4
-.IX Item "-mabi=o64"
-.Ip "\fB\-mabi=n32\fR" 4
-.IX Item "-mabi=n32"
-.Ip "\fB\-mabi=64\fR" 4
-.IX Item "-mabi=64"
-.Ip "\fB\-mabi=eabi\fR" 4
-.IX Item "-mabi=eabi"
-.PD
-Generate code for the indicated \s-1ABI\s0. The default instruction level is
-\&\fB\-mips1\fR for \fB32\fR, \fB\-mips3\fR for \fBn32\fR, and
-\&\fB\-mips4\fR otherwise. Conversely, with \fB\-mips1\fR or
-\&\fB\-mips2\fR, the default \s-1ABI\s0 is \fB32\fR; otherwise, the default \s-1ABI\s0
-is \fB64\fR.
-.Ip "\fB\-mmips-as\fR" 4
-.IX Item "-mmips-as"
-Generate code for the \s-1MIPS\s0 assembler, and invoke \fImips-tfile\fR to
-add normal debug information. This is the default for all
-platforms except for the \s-1OSF/1\s0 reference platform, using the OSF/rose
-object format. If the either of the \fB\-gstabs\fR or \fB\-gstabs+\fR
-switches are used, the \fImips-tfile\fR program will encapsulate the
-stabs within \s-1MIPS\s0 \s-1ECOFF\s0.
-.Ip "\fB\-mgas\fR" 4
-.IX Item "-mgas"
-Generate code for the \s-1GNU\s0 assembler. This is the default on the \s-1OSF/1\s0
-reference platform, using the OSF/rose object format. Also, this is
-the default if the configure option \fB\*(--with-gnu-as\fR is used.
-.Ip "\fB\-msplit-addresses\fR" 4
-.IX Item "-msplit-addresses"
-.PD 0
-.Ip "\fB\-mno-split-addresses\fR" 4
-.IX Item "-mno-split-addresses"
-.PD
-Generate code to load the high and low parts of address constants separately.
-This allows \f(CW\*(C`gcc\*(C'\fR to optimize away redundant loads of the high order
-bits of addresses. This optimization requires \s-1GNU\s0 as and \s-1GNU\s0 ld.
-This optimization is enabled by default for some embedded targets where
-\&\s-1GNU\s0 as and \s-1GNU\s0 ld are standard.
-.Ip "\fB\-mrnames\fR" 4
-.IX Item "-mrnames"
-.PD 0
-.Ip "\fB\-mno-rnames\fR" 4
-.IX Item "-mno-rnames"
-.PD
-The \fB\-mrnames\fR switch says to output code using the \s-1MIPS\s0 software
-names for the registers, instead of the hardware names (ie, \fIa0\fR
-instead of \fI$4\fR). The only known assembler that supports this option
-is the Algorithmics assembler.
-.Ip "\fB\-mgpopt\fR" 4
-.IX Item "-mgpopt"
-.PD 0
-.Ip "\fB\-mno-gpopt\fR" 4
-.IX Item "-mno-gpopt"
-.PD
-The \fB\-mgpopt\fR switch says to write all of the data declarations
-before the instructions in the text section, this allows the \s-1MIPS\s0
-assembler to generate one word memory references instead of using two
-words for short global or static data items. This is on by default if
-optimization is selected.
-.Ip "\fB\-mstats\fR" 4
-.IX Item "-mstats"
-.PD 0
-.Ip "\fB\-mno-stats\fR" 4
-.IX Item "-mno-stats"
-.PD
-For each non-inline function processed, the \fB\-mstats\fR switch
-causes the compiler to emit one line to the standard error file to
-print statistics about the program (number of registers saved, stack
-size, etc.).
-.Ip "\fB\-mmemcpy\fR" 4
-.IX Item "-mmemcpy"
-.PD 0
-.Ip "\fB\-mno-memcpy\fR" 4
-.IX Item "-mno-memcpy"
-.PD
-The \fB\-mmemcpy\fR switch makes all block moves call the appropriate
-string function (\fBmemcpy\fR or \fBbcopy\fR) instead of possibly
-generating inline code.
-.Ip "\fB\-mmips-tfile\fR" 4
-.IX Item "-mmips-tfile"
-.PD 0
-.Ip "\fB\-mno-mips-tfile\fR" 4
-.IX Item "-mno-mips-tfile"
-.PD
-The \fB\-mno-mips-tfile\fR switch causes the compiler not
-postprocess the object file with the \fImips-tfile\fR program,
-after the \s-1MIPS\s0 assembler has generated it to add debug support. If
-\&\fImips-tfile\fR is not run, then no local variables will be
-available to the debugger. In addition, \fIstage2\fR and
-\&\fIstage3\fR objects will have the temporary file names passed to the
-assembler embedded in the object file, which means the objects will
-not compare the same. The \fB\-mno-mips-tfile\fR switch should only
-be used when there are bugs in the \fImips-tfile\fR program that
-prevents compilation.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
-.Ip "\fB\-mhard-float\fR" 4
-.IX Item "-mhard-float"
-Generate output containing floating point instructions. This is the
-default if you use the unmodified sources.
-.Ip "\fB\-mabicalls\fR" 4
-.IX Item "-mabicalls"
-.PD 0
-.Ip "\fB\-mno-abicalls\fR" 4
-.IX Item "-mno-abicalls"
-.PD
-Emit (or do not emit) the pseudo operations \fB.abicalls\fR,
-\&\fB.cpload\fR, and \fB.cprestore\fR that some System V.4 ports use for
-position independent code.
-.Ip "\fB\-mlong-calls\fR" 4
-.IX Item "-mlong-calls"
-.PD 0
-.Ip "\fB\-mno-long-calls\fR" 4
-.IX Item "-mno-long-calls"
-.PD
-Do all calls with the \fB\s-1JALR\s0\fR instruction, which requires
-loading up a function's address into a register before the call.
-You need to use this switch, if you call outside of the current
-512 megabyte segment to functions that are not through pointers.
-.Ip "\fB\-mhalf-pic\fR" 4
-.IX Item "-mhalf-pic"
-.PD 0
-.Ip "\fB\-mno-half-pic\fR" 4
-.IX Item "-mno-half-pic"
-.PD
-Put pointers to extern references into the data section and load them
-up, rather than put the references in the text section.
-.Ip "\fB\-membedded-pic\fR" 4
-.IX Item "-membedded-pic"
-.PD 0
-.Ip "\fB\-mno-embedded-pic\fR" 4
-.IX Item "-mno-embedded-pic"
-.PD
-Generate \s-1PIC\s0 code suitable for some embedded systems. All calls are
-made using \s-1PC\s0 relative address, and all data is addressed using the \f(CW$gp\fR
-register. No more than 65536 bytes of global data may be used. This
-requires \s-1GNU\s0 as and \s-1GNU\s0 ld which do most of the work. This currently
-only works on targets which use \s-1ECOFF\s0; it does not work with \s-1ELF\s0.
-.Ip "\fB\-membedded-data\fR" 4
-.IX Item "-membedded-data"
-.PD 0
-.Ip "\fB\-mno-embedded-data\fR" 4
-.IX Item "-mno-embedded-data"
-.PD
-Allocate variables to the read-only data section first if possible, then
-next in the small data section if possible, otherwise in data. This gives
-slightly slower code than the default, but reduces the amount of \s-1RAM\s0 required
-when executing, and thus may be preferred for some embedded systems.
-.Ip "\fB\-muninit-const-in-rodata\fR" 4
-.IX Item "-muninit-const-in-rodata"
-.PD 0
-.Ip "\fB\-mno-uninit-const-in-rodata\fR" 4
-.IX Item "-mno-uninit-const-in-rodata"
-.PD
-When used together with \fB\-membedded-data\fR, it will always store uninitialized
-const variables in the read-only data section.
-.Ip "\fB\-msingle-float\fR" 4
-.IX Item "-msingle-float"
-.PD 0
-.Ip "\fB\-mdouble-float\fR" 4
-.IX Item "-mdouble-float"
-.PD
-The \fB\-msingle-float\fR switch tells gcc to assume that the floating
-point coprocessor only supports single precision operations, as on the
-\&\fBr4650\fR chip. The \fB\-mdouble-float\fR switch permits gcc to use
-double precision operations. This is the default.
-.Ip "\fB\-mmad\fR" 4
-.IX Item "-mmad"
-.PD 0
-.Ip "\fB\-mno-mad\fR" 4
-.IX Item "-mno-mad"
-.PD
-Permit use of the \fBmad\fR, \fBmadu\fR and \fBmul\fR instructions,
-as on the \fBr4650\fR chip.
-.Ip "\fB\-m4650\fR" 4
-.IX Item "-m4650"
-Turns on \fB\-msingle-float\fR, \fB\-mmad\fR, and, at least for now,
-\&\fB\-mcpu=r4650\fR.
-.Ip "\fB\-mips16\fR" 4
-.IX Item "-mips16"
-.PD 0
-.Ip "\fB\-mno-mips16\fR" 4
-.IX Item "-mno-mips16"
-.PD
-Enable 16\-bit instructions.
-.Ip "\fB\-mentry\fR" 4
-.IX Item "-mentry"
-Use the entry and exit pseudo ops. This option can only be used with
-\&\fB\-mips16\fR.
-.Ip "\fB\-EL\fR" 4
-.IX Item "-EL"
-Compile code for the processor in little endian mode.
-The requisite libraries are assumed to exist.
-.Ip "\fB\-EB\fR" 4
-.IX Item "-EB"
-Compile code for the processor in big endian mode.
-The requisite libraries are assumed to exist.
-.Ip "\fB\-G\fR \fInum\fR" 4
-.IX Item "-G num"
-Put global and static items less than or equal to \fInum\fR bytes into
-the small data or bss sections instead of the normal data or bss
-section. This allows the assembler to emit one word memory reference
-instructions based on the global pointer (\fIgp\fR or \fI$28\fR),
-instead of the normal two words used. By default, \fInum\fR is 8 when
-the \s-1MIPS\s0 assembler is used, and 0 when the \s-1GNU\s0 assembler is used. The
-\&\fB\-G\fR \fInum\fR switch is also passed to the assembler and linker.
-All modules should be compiled with the same \fB\-G\fR \fInum\fR
-value.
-.Ip "\fB\-nocpp\fR" 4
-.IX Item "-nocpp"
-Tell the \s-1MIPS\s0 assembler to not run its preprocessor over user
-assembler files (with a \fB.s\fR suffix) when assembling them.
-.Ip "\fB\-mfix7000\fR" 4
-.IX Item "-mfix7000"
-Pass an option to gas which will cause nops to be inserted if
-the read of the destination register of an mfhi or mflo instruction
-occurs in the following two instructions.
-.Ip "\fB\-no-crt0\fR" 4
-.IX Item "-no-crt0"
-Do not include the default crt0.
-.PP
-.I "Intel 386 Options"
-.IX Subsection "Intel 386 Options"
-.PP
-These \fB\-m\fR options are defined for the i386 family of computers:
-.Ip "\fB\-mcpu=\fR\fIcpu-type\fR" 4
-.IX Item "-mcpu=cpu-type"
-Assume the defaults for the machine type \fIcpu-type\fR when scheduling
-instructions. The choices for \fIcpu-type\fR are \fBi386\fR,
-\&\fBi486\fR, \fBi586\fR, \fBi686\fR, \fBpentium\fR,
-\&\fBpentiumpro\fR, \fBpentium4\fR, \fBk6\fR, and \fBathlon\fR
-.Sp
-While picking a specific \fIcpu-type\fR will schedule things appropriately
-for that particular chip, the compiler will not generate any code that
-does not run on the i386 without the \fB\-march=\fR\fIcpu-type\fR option
-being used. \fBi586\fR is equivalent to \fBpentium\fR and \fBi686\fR
-is equivalent to \fBpentiumpro\fR. \fBk6\fR and \fBathlon\fR are the
-\&\s-1AMD\s0 chips as opposed to the Intel ones.
-.Ip "\fB\-march=\fR\fIcpu-type\fR" 4
-.IX Item "-march=cpu-type"
-Generate instructions for the machine type \fIcpu-type\fR. The choices
-for \fIcpu-type\fR are the same as for \fB\-mcpu\fR. Moreover,
-specifying \fB\-march=\fR\fIcpu-type\fR implies \fB\-mcpu=\fR\fIcpu-type\fR.
-.Ip "\fB\-m386\fR" 4
-.IX Item "-m386"
-.PD 0
-.Ip "\fB\-m486\fR" 4
-.IX Item "-m486"
-.Ip "\fB\-mpentium\fR" 4
-.IX Item "-mpentium"
-.Ip "\fB\-mpentiumpro\fR" 4
-.IX Item "-mpentiumpro"
-.PD
-Synonyms for \fB\-mcpu=i386\fR, \fB\-mcpu=i486\fR, \fB\-mcpu=pentium\fR, and \fB\-mcpu=pentiumpro\fR
-respectively. These synonyms are deprecated.
-.Ip "\fB\-mintel-syntax\fR" 4
-.IX Item "-mintel-syntax"
-Emit assembly using Intel syntax opcodes instead of \s-1AT&T\s0 syntax.
-.Ip "\fB\-mieee-fp\fR" 4
-.IX Item "-mieee-fp"
-.PD 0
-.Ip "\fB\-mno-ieee-fp\fR" 4
-.IX Item "-mno-ieee-fp"
-.PD
-Control whether or not the compiler uses \s-1IEEE\s0 floating point
-comparisons. These handle correctly the case where the result of a
-comparison is unordered.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
-.Sp
-On machines where a function returns floating point results in the 80387
-register stack, some floating point opcodes may be emitted even if
-\&\fB\-msoft-float\fR is used.
-.Ip "\fB\-mno-fp-ret-in-387\fR" 4
-.IX Item "-mno-fp-ret-in-387"
-Do not use the \s-1FPU\s0 registers for return values of functions.
-.Sp
-The usual calling convention has functions return values of types
-\&\f(CW\*(C`float\*(C'\fR and \f(CW\*(C`double\*(C'\fR in an \s-1FPU\s0 register, even if there
-is no \s-1FPU\s0. The idea is that the operating system should emulate
-an \s-1FPU\s0.
-.Sp
-The option \fB\-mno-fp-ret-in-387\fR causes such values to be returned
-in ordinary \s-1CPU\s0 registers instead.
-.Ip "\fB\-mno-fancy-math-387\fR" 4
-.IX Item "-mno-fancy-math-387"
-Some 387 emulators do not support the \f(CW\*(C`sin\*(C'\fR, \f(CW\*(C`cos\*(C'\fR and
-\&\f(CW\*(C`sqrt\*(C'\fR instructions for the 387. Specify this option to avoid
-generating those instructions. This option is the default on FreeBSD.
-As of revision 2.6.1, these instructions are not generated unless you
-also use the \fB\-funsafe-math-optimizations\fR switch.
-.Ip "\fB\-malign-double\fR" 4
-.IX Item "-malign-double"
-.PD 0
-.Ip "\fB\-mno-align-double\fR" 4
-.IX Item "-mno-align-double"
-.PD
-Control whether \s-1GCC\s0 aligns \f(CW\*(C`double\*(C'\fR, \f(CW\*(C`long double\*(C'\fR, and
-\&\f(CW\*(C`long long\*(C'\fR variables on a two word boundary or a one word
-boundary. Aligning \f(CW\*(C`double\*(C'\fR variables on a two word boundary will
-produce code that runs somewhat faster on a \fBPentium\fR at the
-expense of more memory.
-.Ip "\fB\-m128bit-long-double\fR" 4
-.IX Item "-m128bit-long-double"
-.PD 0
-.Ip "\fB\-m128bit-long-double\fR" 4
-.IX Item "-m128bit-long-double"
-.PD
-Control the size of \f(CW\*(C`long double\*(C'\fR type. i386 application binary interface
-specify the size to be 12 bytes, while modern architectures (Pentium and newer)
-prefer \f(CW\*(C`long double\*(C'\fR aligned to 8 or 16 byte boundary. This is
-impossible to reach with 12 byte long doubles in the array accesses.
-.Sp
-\&\fBWarning:\fR if you use the \fB\-m128bit-long-double\fR switch, the
-structures and arrays containing \f(CW\*(C`long double\*(C'\fR will change their size as
-well as function calling convention for function taking \f(CW\*(C`long double\*(C'\fR
-will be modified.
-.Ip "\fB\-m96bit-long-double\fR" 4
-.IX Item "-m96bit-long-double"
-.PD 0
-.Ip "\fB\-m96bit-long-double\fR" 4
-.IX Item "-m96bit-long-double"
-.PD
-Set the size of \f(CW\*(C`long double\*(C'\fR to 96 bits as required by the i386
-application binary interface. This is the default.
-.Ip "\fB\-msvr3\-shlib\fR" 4
-.IX Item "-msvr3-shlib"
-.PD 0
-.Ip "\fB\-mno-svr3\-shlib\fR" 4
-.IX Item "-mno-svr3-shlib"
-.PD
-Control whether \s-1GCC\s0 places uninitialized locals into \f(CW\*(C`bss\*(C'\fR or
-\&\f(CW\*(C`data\*(C'\fR. \fB\-msvr3\-shlib\fR places these locals into \f(CW\*(C`bss\*(C'\fR.
-These options are meaningful only on System V Release 3.
-.Ip "\fB\-mno-wide-multiply\fR" 4
-.IX Item "-mno-wide-multiply"
-.PD 0
-.Ip "\fB\-mwide-multiply\fR" 4
-.IX Item "-mwide-multiply"
-.PD
-Control whether \s-1GCC\s0 uses the \f(CW\*(C`mul\*(C'\fR and \f(CW\*(C`imul\*(C'\fR that produce
-64\-bit results in \f(CW\*(C`eax:edx\*(C'\fR from 32\-bit operands to do \f(CW\*(C`long
-long\*(C'\fR multiplies and 32\-bit division by constants.
-.Ip "\fB\-mrtd\fR" 4
-.IX Item "-mrtd"
-Use a different function-calling convention, in which functions that
-take a fixed number of arguments return with the \f(CW\*(C`ret\*(C'\fR \fInum\fR
-instruction, which pops their arguments while returning. This saves one
-instruction in the caller since there is no need to pop the arguments
-there.
-.Sp
-You can specify that an individual function is called with this calling
-sequence with the function attribute \fBstdcall\fR. You can also
-override the \fB\-mrtd\fR option by using the function attribute
-\&\fBcdecl\fR.
-.Sp
-\&\fBWarning:\fR this calling convention is incompatible with the one
-normally used on Unix, so you cannot use it if you need to call
-libraries compiled with the Unix compiler.
-.Sp
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR);
-otherwise incorrect code will be generated for calls to those
-functions.
-.Sp
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
-.Ip "\fB\-mregparm=\fR\fInum\fR" 4
-.IX Item "-mregparm=num"
-Control how many registers are used to pass integer arguments. By
-default, no registers are used to pass arguments, and at most 3
-registers can be used. You can control this behavior for a specific
-function by using the function attribute \fBregparm\fR.
-.Sp
-\&\fBWarning:\fR if you use this switch, and
-\&\fInum\fR is nonzero, then you must build all modules with the same
-value, including any libraries. This includes the system libraries and
-startup modules.
-.Ip "\fB\-mpreferred-stack-boundary=\fR\fInum\fR" 4
-.IX Item "-mpreferred-stack-boundary=num"
-Attempt to keep the stack boundary aligned to a 2 raised to \fInum\fR
-byte boundary. If \fB\-mpreferred-stack-boundary\fR is not specified,
-the default is 4 (16 bytes or 128 bits).
-.Sp
-The stack is required to be aligned on a 4 byte boundary. On Pentium
-and PentiumPro, \f(CW\*(C`double\*(C'\fR and \f(CW\*(C`long double\*(C'\fR values should be
-aligned to an 8 byte boundary (see \fB\-malign-double\fR) or suffer
-significant run time performance penalties. On Pentium \s-1III\s0, the
-Streaming \s-1SIMD\s0 Extension (\s-1SSE\s0) data type \f(CW\*(C`_\|_m128\*(C'\fR suffers similar
-penalties if it is not 16 byte aligned.
-.Sp
-To ensure proper alignment of this values on the stack, the stack boundary
-must be as aligned as that required by any value stored on the stack.
-Further, every function must be generated such that it keeps the stack
-aligned. Thus calling a function compiled with a higher preferred
-stack boundary from a function compiled with a lower preferred stack
-boundary will most likely misalign the stack. It is recommended that
-libraries that use callbacks always use the default setting.
-.Sp
-This extra alignment does consume extra stack space. Code that is sensitive
-to stack space usage, such as embedded systems and operating system kernels,
-may want to reduce the preferred alignment to
-\&\fB\-mpreferred-stack-boundary=2\fR.
-.Ip "\fB\-mpush-args\fR" 4
-.IX Item "-mpush-args"
-Use \s-1PUSH\s0 operations to store outgoing parameters. This method is shorter
-and usually equally fast as method using \s-1SUB/MOV\s0 operations and is enabled
-by default. In some cases disabling it may improve performance because of
-improved scheduling and reduced dependencies.
-.Ip "\fB\-maccumulate-outgoing-args\fR" 4
-.IX Item "-maccumulate-outgoing-args"
-If enabled, the maximum amount of space required for outgoing arguments will be
-computed in the function prologue. This in faster on most modern CPUs
-because of reduced dependencies, improved scheduling and reduced stack usage
-when preferred stack boundary is not equal to 2. The drawback is a notable
-increase in code size. This switch implies \fB\-mno-push-args\fR.
-.Ip "\fB\-mthreads\fR" 4
-.IX Item "-mthreads"
-Support thread-safe exception handling on \fBMingw32\fR. Code that relies
-on thread-safe exception handling must compile and link all code with the
-\&\fB\-mthreads\fR option. When compiling, \fB\-mthreads\fR defines
-\&\fB\-D_MT\fR; when linking, it links in a special thread helper library
-\&\fB\-lmingwthrd\fR which cleans up per thread exception handling data.
-.Ip "\fB\-mno-align-stringops\fR" 4
-.IX Item "-mno-align-stringops"
-Do not align destination of inlined string operations. This switch reduces
-code size and improves performance in case the destination is already aligned,
-but gcc don't know about it.
-.Ip "\fB\-minline-all-stringops\fR" 4
-.IX Item "-minline-all-stringops"
-By default \s-1GCC\s0 inlines string operations only when destination is known to be
-aligned at least to 4 byte boundary. This enables more inlining, increase code
-size, but may improve performance of code that depends on fast memcpy, strlen
-and memset for short lengths.
-.Ip "\fB\-momit-leaf-frame-pointer\fR" 4
-.IX Item "-momit-leaf-frame-pointer"
-Don't keep the frame pointer in a register for leaf functions. This
-avoids the instructions to save, set up and restore frame pointers and
-makes an extra register available in leaf functions. The option
-\&\fB\-fomit-frame-pointer\fR removes the frame pointer for all functions
-which might make debugging harder.
-.PP
-.I "\s-1HPPA\s0 Options"
-.IX Subsection "HPPA Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1HPPA\s0 family of computers:
-.Ip "\fB\-march=\fR\fIarchitecture-type\fR" 4
-.IX Item "-march=architecture-type"
-Generate code for the specified architecture. The choices for
-\&\fIarchitecture-type\fR are \fB1.0\fR for \s-1PA\s0 1.0, \fB1.1\fR for \s-1PA\s0
-1.1, and \fB2.0\fR for \s-1PA\s0 2.0 processors. Refer to
-\&\fI/usr/lib/sched.models\fR on an \s-1HP-UX\s0 system to determine the proper
-architecture option for your machine. Code compiled for lower numbered
-architectures will run on higher numbered architectures, but not the
-other way around.
-.Sp
-\&\s-1PA\s0 2.0 support currently requires gas snapshot 19990413 or later. The
-next release of binutils (current is 2.9.1) will probably contain \s-1PA\s0 2.0
-support.
-.Ip "\fB\-mpa-risc-1\-0\fR" 4
-.IX Item "-mpa-risc-1-0"
-.PD 0
-.Ip "\fB\-mpa-risc-1\-1\fR" 4
-.IX Item "-mpa-risc-1-1"
-.Ip "\fB\-mpa-risc-2\-0\fR" 4
-.IX Item "-mpa-risc-2-0"
-.PD
-Synonyms for \fB\-march=1.0\fR, \fB\-march=1.1\fR, and \fB\-march=2.0\fR respectively.
-.Ip "\fB\-mbig-switch\fR" 4
-.IX Item "-mbig-switch"
-Generate code suitable for big switch tables. Use this option only if
-the assembler/linker complain about out of range branches within a switch
-table.
-.Ip "\fB\-mjump-in-delay\fR" 4
-.IX Item "-mjump-in-delay"
-Fill delay slots of function calls with unconditional jump instructions
-by modifying the return pointer for the function call to be the target
-of the conditional jump.
-.Ip "\fB\-mdisable-fpregs\fR" 4
-.IX Item "-mdisable-fpregs"
-Prevent floating point registers from being used in any manner. This is
-necessary for compiling kernels which perform lazy context switching of
-floating point registers. If you use this option and attempt to perform
-floating point operations, the compiler will abort.
-.Ip "\fB\-mdisable-indexing\fR" 4
-.IX Item "-mdisable-indexing"
-Prevent the compiler from using indexing address modes. This avoids some
-rather obscure problems when compiling \s-1MIG\s0 generated code under \s-1MACH\s0.
-.Ip "\fB\-mno-space-regs\fR" 4
-.IX Item "-mno-space-regs"
-Generate code that assumes the target has no space registers. This allows
-\&\s-1GCC\s0 to generate faster indirect calls and use unscaled index address modes.
-.Sp
-Such code is suitable for level 0 \s-1PA\s0 systems and kernels.
-.Ip "\fB\-mfast-indirect-calls\fR" 4
-.IX Item "-mfast-indirect-calls"
-Generate code that assumes calls never cross space boundaries. This
-allows \s-1GCC\s0 to emit code which performs faster indirect calls.
-.Sp
-This option will not work in the presence of shared libraries or nested
-functions.
-.Ip "\fB\-mlong-load-store\fR" 4
-.IX Item "-mlong-load-store"
-Generate 3\-instruction load and store sequences as sometimes required by
-the \s-1HP-UX\s0 10 linker. This is equivalent to the \fB+k\fR option to
-the \s-1HP\s0 compilers.
-.Ip "\fB\-mportable-runtime\fR" 4
-.IX Item "-mportable-runtime"
-Use the portable calling conventions proposed by \s-1HP\s0 for \s-1ELF\s0 systems.
-.Ip "\fB\-mgas\fR" 4
-.IX Item "-mgas"
-Enable the use of assembler directives only \s-1GAS\s0 understands.
-.Ip "\fB\-mschedule=\fR\fIcpu-type\fR" 4
-.IX Item "-mschedule=cpu-type"
-Schedule code according to the constraints for the machine type
-\&\fIcpu-type\fR. The choices for \fIcpu-type\fR are \fB700\fR
-\&\fB7100\fR, \fB7100LC\fR, \fB7200\fR, and \fB8000\fR. Refer to
-\&\fI/usr/lib/sched.models\fR on an \s-1HP-UX\s0 system to determine the
-proper scheduling option for your machine.
-.Ip "\fB\-mlinker-opt\fR" 4
-.IX Item "-mlinker-opt"
-Enable the optimization pass in the \s-1HPUX\s0 linker. Note this makes symbolic
-debugging impossible. It also triggers a bug in the \s-1HPUX\s0 8 and \s-1HPUX\s0 9 linkers
-in which they give bogus error messages when linking some programs.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries are not available for all \s-1HPPA\s0
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation. The embedded target \fBhppa1.1\-*\-pro\fR
-does provide software floating point support.
-.Sp
-\&\fB\-msoft-float\fR changes the calling convention in the output file;
-therefore, it is only useful if you compile \fIall\fR of a program with
-this option. In particular, you need to compile \fIlibgcc.a\fR, the
-library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for
-this to work.
-.PP
-.I "Intel 960 Options"
-.IX Subsection "Intel 960 Options"
-.PP
-These \fB\-m\fR options are defined for the Intel 960 implementations:
-.Ip "\fB\-m\fR\fIcpu-type\fR" 4
-.IX Item "-mcpu-type"
-Assume the defaults for the machine type \fIcpu-type\fR for some of
-the other options, including instruction scheduling, floating point
-support, and addressing modes. The choices for \fIcpu-type\fR are
-\&\fBka\fR, \fBkb\fR, \fBmc\fR, \fBca\fR, \fBcf\fR,
-\&\fBsa\fR, and \fBsb\fR.
-The default is
-\&\fBkb\fR.
-.Ip "\fB\-mnumerics\fR" 4
-.IX Item "-mnumerics"
-.PD 0
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-.PD
-The \fB\-mnumerics\fR option indicates that the processor does support
-floating-point instructions. The \fB\-msoft-float\fR option indicates
-that floating-point support should not be assumed.
-.Ip "\fB\-mleaf-procedures\fR" 4
-.IX Item "-mleaf-procedures"
-.PD 0
-.Ip "\fB\-mno-leaf-procedures\fR" 4
-.IX Item "-mno-leaf-procedures"
-.PD
-Do (or do not) attempt to alter leaf procedures to be callable with the
-\&\f(CW\*(C`bal\*(C'\fR instruction as well as \f(CW\*(C`call\*(C'\fR. This will result in more
-efficient code for explicit calls when the \f(CW\*(C`bal\*(C'\fR instruction can be
-substituted by the assembler or linker, but less efficient code in other
-cases, such as calls via function pointers, or using a linker that doesn't
-support this optimization.
-.Ip "\fB\-mtail-call\fR" 4
-.IX Item "-mtail-call"
-.PD 0
-.Ip "\fB\-mno-tail-call\fR" 4
-.IX Item "-mno-tail-call"
-.PD
-Do (or do not) make additional attempts (beyond those of the
-machine-independent portions of the compiler) to optimize tail-recursive
-calls into branches. You may not want to do this because the detection of
-cases where this is not valid is not totally complete. The default is
-\&\fB\-mno-tail-call\fR.
-.Ip "\fB\-mcomplex-addr\fR" 4
-.IX Item "-mcomplex-addr"
-.PD 0
-.Ip "\fB\-mno-complex-addr\fR" 4
-.IX Item "-mno-complex-addr"
-.PD
-Assume (or do not assume) that the use of a complex addressing mode is a
-win on this implementation of the i960. Complex addressing modes may not
-be worthwhile on the K-series, but they definitely are on the C-series.
-The default is currently \fB\-mcomplex-addr\fR for all processors except
-the \s-1CB\s0 and \s-1CC\s0.
-.Ip "\fB\-mcode-align\fR" 4
-.IX Item "-mcode-align"
-.PD 0
-.Ip "\fB\-mno-code-align\fR" 4
-.IX Item "-mno-code-align"
-.PD
-Align code to 8\-byte boundaries for faster fetching (or don't bother).
-Currently turned on by default for C-series implementations only.
-.Ip "\fB\-mic-compat\fR" 4
-.IX Item "-mic-compat"
-.PD 0
-.Ip "\fB\-mic2.0\-compat\fR" 4
-.IX Item "-mic2.0-compat"
-.Ip "\fB\-mic3.0\-compat\fR" 4
-.IX Item "-mic3.0-compat"
-.PD
-Enable compatibility with iC960 v2.0 or v3.0.
-.Ip "\fB\-masm-compat\fR" 4
-.IX Item "-masm-compat"
-.PD 0
-.Ip "\fB\-mintel-asm\fR" 4
-.IX Item "-mintel-asm"
-.PD
-Enable compatibility with the iC960 assembler.
-.Ip "\fB\-mstrict-align\fR" 4
-.IX Item "-mstrict-align"
-.PD 0
-.Ip "\fB\-mno-strict-align\fR" 4
-.IX Item "-mno-strict-align"
-.PD
-Do not permit (do permit) unaligned accesses.
-.Ip "\fB\-mold-align\fR" 4
-.IX Item "-mold-align"
-Enable structure-alignment compatibility with Intel's gcc release version
-1.3 (based on gcc 1.37). This option implies \fB\-mstrict-align\fR.
-.Ip "\fB\-mlong-double-64\fR" 4
-.IX Item "-mlong-double-64"
-Implement type \fBlong double\fR as 64\-bit floating point numbers.
-Without the option \fBlong double\fR is implemented by 80\-bit
-floating point numbers. The only reason we have it because there is
-no 128\-bit \fBlong double\fR support in \fBfp-bit.c\fR yet. So it
-is only useful for people using soft-float targets. Otherwise, we
-should recommend against use of it.
-.PP
-.I "\s-1DEC\s0 Alpha Options"
-.IX Subsection "DEC Alpha Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1DEC\s0 Alpha implementations:
-.Ip "\fB\-mno-soft-float\fR" 4
-.IX Item "-mno-soft-float"
-.PD 0
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-.PD
-Use (do not use) the hardware floating-point instructions for
-floating-point operations. When \fB\-msoft-float\fR is specified,
-functions in \fIlibgcc.a\fR will be used to perform floating-point
-operations. Unless they are replaced by routines that emulate the
-floating-point operations, or compiled in such a way as to call such
-emulations routines, these routines will issue floating-point
-operations. If you are compiling for an Alpha without floating-point
-operations, you must ensure that the library is built so as not to call
-them.
-.Sp
-Note that Alpha implementations without floating-point operations are
-required to have floating-point registers.
-.Ip "\fB\-mfp-reg\fR" 4
-.IX Item "-mfp-reg"
-.PD 0
-.Ip "\fB\-mno-fp-regs\fR" 4
-.IX Item "-mno-fp-regs"
-.PD
-Generate code that uses (does not use) the floating-point register set.
-\&\fB\-mno-fp-regs\fR implies \fB\-msoft-float\fR. If the floating-point
-register set is not used, floating point operands are passed in integer
-registers as if they were integers and floating-point results are passed
-in \f(CW$0\fR instead of \f(CW$f0\fR. This is a non-standard calling sequence, so any
-function with a floating-point argument or return value called by code
-compiled with \fB\-mno-fp-regs\fR must also be compiled with that
-option.
-.Sp
-A typical use of this option is building a kernel that does not use,
-and hence need not save and restore, any floating-point registers.
-.Ip "\fB\-mieee\fR" 4
-.IX Item "-mieee"
-The Alpha architecture implements floating-point hardware optimized for
-maximum performance. It is mostly compliant with the \s-1IEEE\s0 floating
-point standard. However, for full compliance, software assistance is
-required. This option generates code fully \s-1IEEE\s0 compliant code
-\&\fIexcept\fR that the \fIinexact-flag\fR is not maintained (see below).
-If this option is turned on, the \s-1CPP\s0 macro \f(CW\*(C`_IEEE_FP\*(C'\fR is defined
-during compilation. The option is a shorthand for: \fB\-D_IEEE_FP
-\&\-mfp-trap-mode=su \-mtrap-precision=i \-mieee-conformant\fR. The resulting
-code is less efficient but is able to correctly support denormalized
-numbers and exceptional \s-1IEEE\s0 values such as not-a-number and plus/minus
-infinity. Other Alpha compilers call this option
-\&\fB\-ieee_with_no_inexact\fR.
-.Ip "\fB\-mieee-with-inexact\fR" 4
-.IX Item "-mieee-with-inexact"
-This is like \fB\-mieee\fR except the generated code also maintains the
-\&\s-1IEEE\s0 \fIinexact-flag\fR. Turning on this option causes the generated
-code to implement fully-compliant \s-1IEEE\s0 math. The option is a shorthand
-for \fB\-D_IEEE_FP \-D_IEEE_FP_INEXACT\fR plus the three following:
-\&\fB\-mieee-conformant\fR,
-\&\fB\-mfp-trap-mode=sui\fR,
-and \fB\-mtrap-precision=i\fR.
-On some Alpha implementations the resulting code may execute
-significantly slower than the code generated by default. Since there
-is very little code that depends on the \fIinexact-flag\fR, you should
-normally not specify this option. Other Alpha compilers call this
-option \fB\-ieee_with_inexact\fR.
-.Ip "\fB\-mfp-trap-mode=\fR\fItrap-mode\fR" 4
-.IX Item "-mfp-trap-mode=trap-mode"
-This option controls what floating-point related traps are enabled.
-Other Alpha compilers call this option \fB\-fptm\fR \fItrap-mode\fR.
-The trap mode can be set to one of four values:
-.RS 4
-.Ip "\fBn\fR" 4
-.IX Item "n"
-This is the default (normal) setting. The only traps that are enabled
-are the ones that cannot be disabled in software (e.g., division by zero
-trap).
-.Ip "\fBu\fR" 4
-.IX Item "u"
-In addition to the traps enabled by \fBn\fR, underflow traps are enabled
-as well.
-.Ip "\fBsu\fR" 4
-.IX Item "su"
-Like \fBsu\fR, but the instructions are marked to be safe for software
-completion (see Alpha architecture manual for details).
-.Ip "\fBsui\fR" 4
-.IX Item "sui"
-Like \fBsu\fR, but inexact traps are enabled as well.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-mfp-rounding-mode=\fR\fIrounding-mode\fR" 4
-.IX Item "-mfp-rounding-mode=rounding-mode"
-Selects the \s-1IEEE\s0 rounding mode. Other Alpha compilers call this option
-\&\fB\-fprm\fR \fIrounding-mode\fR. The \fIrounding-mode\fR can be one
-of:
-.RS 4
-.Ip "\fBn\fR" 4
-.IX Item "n"
-Normal \s-1IEEE\s0 rounding mode. Floating point numbers are rounded towards
-the nearest machine number or towards the even machine number in case
-of a tie.
-.Ip "\fBm\fR" 4
-.IX Item "m"
-Round towards minus infinity.
-.Ip "\fBc\fR" 4
-.IX Item "c"
-Chopped rounding mode. Floating point numbers are rounded towards zero.
-.Ip "\fBd\fR" 4
-.IX Item "d"
-Dynamic rounding mode. A field in the floating point control register
-(\fIfpcr\fR, see Alpha architecture reference manual) controls the
-rounding mode in effect. The C library initializes this register for
-rounding towards plus infinity. Thus, unless your program modifies the
-\&\fIfpcr\fR, \fBd\fR corresponds to round towards plus infinity.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-mtrap-precision=\fR\fItrap-precision\fR" 4
-.IX Item "-mtrap-precision=trap-precision"
-In the Alpha architecture, floating point traps are imprecise. This
-means without software assistance it is impossible to recover from a
-floating trap and program execution normally needs to be terminated.
-\&\s-1GCC\s0 can generate code that can assist operating system trap handlers
-in determining the exact location that caused a floating point trap.
-Depending on the requirements of an application, different levels of
-precisions can be selected:
-.RS 4
-.Ip "\fBp\fR" 4
-.IX Item "p"
-Program precision. This option is the default and means a trap handler
-can only identify which program caused a floating point exception.
-.Ip "\fBf\fR" 4
-.IX Item "f"
-Function precision. The trap handler can determine the function that
-caused a floating point exception.
-.Ip "\fBi\fR" 4
-.IX Item "i"
-Instruction precision. The trap handler can determine the exact
-instruction that caused a floating point exception.
-.RE
-.RS 4
-.Sp
-Other Alpha compilers provide the equivalent options called
-\&\fB\-scope_safe\fR and \fB\-resumption_safe\fR.
-.RE
-.Ip "\fB\-mieee-conformant\fR" 4
-.IX Item "-mieee-conformant"
-This option marks the generated code as \s-1IEEE\s0 conformant. You must not
-use this option unless you also specify \fB\-mtrap-precision=i\fR and either
-\&\fB\-mfp-trap-mode=su\fR or \fB\-mfp-trap-mode=sui\fR. Its only effect
-is to emit the line \fB.eflag 48\fR in the function prologue of the
-generated assembly file. Under \s-1DEC\s0 Unix, this has the effect that
-IEEE-conformant math library routines will be linked in.
-.Ip "\fB\-mbuild-constants\fR" 4
-.IX Item "-mbuild-constants"
-Normally \s-1GCC\s0 examines a 32\- or 64\-bit integer constant to
-see if it can construct it from smaller constants in two or three
-instructions. If it cannot, it will output the constant as a literal and
-generate code to load it from the data segment at runtime.
-.Sp
-Use this option to require \s-1GCC\s0 to construct \fIall\fR integer constants
-using code, even if it takes more instructions (the maximum is six).
-.Sp
-You would typically use this option to build a shared library dynamic
-loader. Itself a shared library, it must relocate itself in memory
-before it can find the variables and constants in its own data segment.
-.Ip "\fB\-malpha-as\fR" 4
-.IX Item "-malpha-as"
-.PD 0
-.Ip "\fB\-mgas\fR" 4
-.IX Item "-mgas"
-.PD
-Select whether to generate code to be assembled by the vendor-supplied
-assembler (\fB\-malpha-as\fR) or by the \s-1GNU\s0 assembler \fB\-mgas\fR.
-.Ip "\fB\-mbwx\fR" 4
-.IX Item "-mbwx"
-.PD 0
-.Ip "\fB\-mno-bwx\fR" 4
-.IX Item "-mno-bwx"
-.Ip "\fB\-mcix\fR" 4
-.IX Item "-mcix"
-.Ip "\fB\-mno-cix\fR" 4
-.IX Item "-mno-cix"
-.Ip "\fB\-mmax\fR" 4
-.IX Item "-mmax"
-.Ip "\fB\-mno-max\fR" 4
-.IX Item "-mno-max"
-.PD
-Indicate whether \s-1GCC\s0 should generate code to use the optional \s-1BWX\s0,
-\&\s-1CIX\s0, and \s-1MAX\s0 instruction sets. The default is to use the instruction sets
-supported by the \s-1CPU\s0 type specified via \fB\-mcpu=\fR option or that
-of the \s-1CPU\s0 on which \s-1GCC\s0 was built if none was specified.
-.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4
-.IX Item "-mcpu=cpu_type"
-Set the instruction set, register set, and instruction scheduling
-parameters for machine type \fIcpu_type\fR. You can specify either the
-\&\fB\s-1EV\s0\fR style name or the corresponding chip number. \s-1GCC\s0
-supports scheduling parameters for the \s-1EV4\s0 and \s-1EV5\s0 family of processors
-and will choose the default values for the instruction set from
-the processor you specify. If you do not specify a processor type,
-\&\s-1GCC\s0 will default to the processor on which the compiler was built.
-.Sp
-Supported values for \fIcpu_type\fR are
-.RS 4
-.Ip "\fBev4\fR" 4
-.IX Item "ev4"
-.PD 0
-.Ip "\fB21064\fR" 4
-.IX Item "21064"
-.PD
-Schedules as an \s-1EV4\s0 and has no instruction set extensions.
-.Ip "\fBev5\fR" 4
-.IX Item "ev5"
-.PD 0
-.Ip "\fB21164\fR" 4
-.IX Item "21164"
-.PD
-Schedules as an \s-1EV5\s0 and has no instruction set extensions.
-.Ip "\fBev56\fR" 4
-.IX Item "ev56"
-.PD 0
-.Ip "\fB21164a\fR" 4
-.IX Item "21164a"
-.PD
-Schedules as an \s-1EV5\s0 and supports the \s-1BWX\s0 extension.
-.Ip "\fBpca56\fR" 4
-.IX Item "pca56"
-.PD 0
-.Ip "\fB21164pc\fR" 4
-.IX Item "21164pc"
-.Ip "\fB21164PC\fR" 4
-.IX Item "21164PC"
-.PD
-Schedules as an \s-1EV5\s0 and supports the \s-1BWX\s0 and \s-1MAX\s0 extensions.
-.Ip "\fBev6\fR" 4
-.IX Item "ev6"
-.PD 0
-.Ip "\fB21264\fR" 4
-.IX Item "21264"
-.PD
-Schedules as an \s-1EV5\s0 (until Digital releases the scheduling parameters
-for the \s-1EV6\s0) and supports the \s-1BWX\s0, \s-1CIX\s0, and \s-1MAX\s0 extensions.
-.RE
-.RS 4
-.RE
-.Ip "\fB\-mmemory-latency=\fR\fItime\fR" 4
-.IX Item "-mmemory-latency=time"
-Sets the latency the scheduler should assume for typical memory
-references as seen by the application. This number is highly
-dependent on the memory access patterns used by the application
-and the size of the external cache on the machine.
-.Sp
-Valid options for \fItime\fR are
-.RS 4
-.Ip "\fInumber\fR" 4
-.IX Item "number"
-A decimal number representing clock cycles.
-.Ip "\fBL1\fR" 4
-.IX Item "L1"
-.PD 0
-.Ip "\fBL2\fR" 4
-.IX Item "L2"
-.Ip "\fBL3\fR" 4
-.IX Item "L3"
-.Ip "\fBmain\fR" 4
-.IX Item "main"
-.PD
-The compiler contains estimates of the number of clock cycles for
-``typical'' \s-1EV4\s0 & \s-1EV5\s0 hardware for the Level 1, 2 & 3 caches
-(also called Dcache, Scache, and Bcache), as well as to main memory.
-Note that L3 is only valid for \s-1EV5\s0.
-.RE
-.RS 4
-.RE
-.PP
-.I "Clipper Options"
-.IX Subsection "Clipper Options"
-.PP
-These \fB\-m\fR options are defined for the Clipper implementations:
-.Ip "\fB\-mc300\fR" 4
-.IX Item "-mc300"
-Produce code for a C300 Clipper processor. This is the default.
-.Ip "\fB\-mc400\fR" 4
-.IX Item "-mc400"
-Produce code for a C400 Clipper processor i.e. use floating point
-registers f8\-\-\-f15.
-.PP
-.I "H8/300 Options"
-.IX Subsection "H8/300 Options"
-.PP
-These \fB\-m\fR options are defined for the H8/300 implementations:
-.Ip "\fB\-mrelax\fR" 4
-.IX Item "-mrelax"
-Shorten some address references at link time, when possible; uses the
-linker option \fB\-relax\fR.
-.Ip "\fB\-mh\fR" 4
-.IX Item "-mh"
-Generate code for the H8/300H.
-.Ip "\fB\-ms\fR" 4
-.IX Item "-ms"
-Generate code for the H8/S.
-.Ip "\fB\-ms2600\fR" 4
-.IX Item "-ms2600"
-Generate code for the H8/S2600. This switch must be used with \fB\-ms\fR.
-.Ip "\fB\-mint32\fR" 4
-.IX Item "-mint32"
-Make \f(CW\*(C`int\*(C'\fR data 32 bits by default.
-.Ip "\fB\-malign-300\fR" 4
-.IX Item "-malign-300"
-On the H8/300H and H8/S, use the same alignment rules as for the H8/300.
-The default for the H8/300H and H8/S is to align longs and floats on 4
-byte boundaries.
-\&\fB\-malign-300\fR causes them to be aligned on 2 byte boundaries.
-This option has no effect on the H8/300.
-.PP
-.I "\s-1SH\s0 Options"
-.IX Subsection "SH Options"
-.PP
-These \fB\-m\fR options are defined for the \s-1SH\s0 implementations:
-.Ip "\fB\-m1\fR" 4
-.IX Item "-m1"
-Generate code for the \s-1SH1\s0.
-.Ip "\fB\-m2\fR" 4
-.IX Item "-m2"
-Generate code for the \s-1SH2\s0.
-.Ip "\fB\-m3\fR" 4
-.IX Item "-m3"
-Generate code for the \s-1SH3\s0.
-.Ip "\fB\-m3e\fR" 4
-.IX Item "-m3e"
-Generate code for the SH3e.
-.Ip "\fB\-m4\-nofpu\fR" 4
-.IX Item "-m4-nofpu"
-Generate code for the \s-1SH4\s0 without a floating-point unit.
-.Ip "\fB\-m4\-single-only\fR" 4
-.IX Item "-m4-single-only"
-Generate code for the \s-1SH4\s0 with a floating-point unit that only
-supports single-precision arithmetic.
-.Ip "\fB\-m4\-single\fR" 4
-.IX Item "-m4-single"
-Generate code for the \s-1SH4\s0 assuming the floating-point unit is in
-single-precision mode by default.
-.Ip "\fB\-m4\fR" 4
-.IX Item "-m4"
-Generate code for the \s-1SH4\s0.
-.Ip "\fB\-mb\fR" 4
-.IX Item "-mb"
-Compile code for the processor in big endian mode.
-.Ip "\fB\-ml\fR" 4
-.IX Item "-ml"
-Compile code for the processor in little endian mode.
-.Ip "\fB\-mdalign\fR" 4
-.IX Item "-mdalign"
-Align doubles at 64\-bit boundaries. Note that this changes the calling
-conventions, and thus some functions from the standard C library will
-not work unless you recompile it first with \fB\-mdalign\fR.
-.Ip "\fB\-mrelax\fR" 4
-.IX Item "-mrelax"
-Shorten some address references at link time, when possible; uses the
-linker option \fB\-relax\fR.
-.Ip "\fB\-mbigtable\fR" 4
-.IX Item "-mbigtable"
-Use 32\-bit offsets in \f(CW\*(C`switch\*(C'\fR tables. The default is to use
-16\-bit offsets.
-.Ip "\fB\-mfmovd\fR" 4
-.IX Item "-mfmovd"
-Enable the use of the instruction \f(CW\*(C`fmovd\*(C'\fR.
-.Ip "\fB\-mhitachi\fR" 4
-.IX Item "-mhitachi"
-Comply with the calling conventions defined by Hitachi.
-.Ip "\fB\-mnomacsave\fR" 4
-.IX Item "-mnomacsave"
-Mark the \f(CW\*(C`MAC\*(C'\fR register as call-clobbered, even if
-\&\fB\-mhitachi\fR is given.
-.Ip "\fB\-mieee\fR" 4
-.IX Item "-mieee"
-Increase IEEE-compliance of floating-point code.
-.Ip "\fB\-misize\fR" 4
-.IX Item "-misize"
-Dump instruction size and location in the assembly code.
-.Ip "\fB\-mpadstruct\fR" 4
-.IX Item "-mpadstruct"
-This option is deprecated. It pads structures to multiple of 4 bytes,
-which is incompatible with the \s-1SH\s0 \s-1ABI\s0.
-.Ip "\fB\-mspace\fR" 4
-.IX Item "-mspace"
-Optimize for space instead of speed. Implied by \fB\-Os\fR.
-.Ip "\fB\-mprefergot\fR" 4
-.IX Item "-mprefergot"
-When generating position-independent code, emit function calls using
-the Global Offset Table instead of the Procedure Linkage Table.
-.Ip "\fB\-musermode\fR" 4
-.IX Item "-musermode"
-Generate a library function call to invalidate instruction cache
-entries, after fixing up a trampoline. This library function call
-doesn't assume it can write to the whole memory address space. This
-is the default when the target is \f(CW\*(C`sh\-*\-linux*\*(C'\fR.
-.PP
-.I "Options for System V"
-.IX Subsection "Options for System V"
-.PP
-These additional options are available on System V Release 4 for
-compatibility with other compilers on those systems:
-.Ip "\fB\-G\fR" 4
-.IX Item "-G"
-Create a shared object.
-It is recommended that \fB\-symbolic\fR or \fB\-shared\fR be used instead.
-.Ip "\fB\-Qy\fR" 4
-.IX Item "-Qy"
-Identify the versions of each tool used by the compiler, in a
-\&\f(CW\*(C`.ident\*(C'\fR assembler directive in the output.
-.Ip "\fB\-Qn\fR" 4
-.IX Item "-Qn"
-Refrain from adding \f(CW\*(C`.ident\*(C'\fR directives to the output file (this is
-the default).
-.Ip "\fB\-YP,\fR\fIdirs\fR" 4
-.IX Item "-YP,dirs"
-Search the directories \fIdirs\fR, and no others, for libraries
-specified with \fB\-l\fR.
-.Ip "\fB\-Ym,\fR\fIdir\fR" 4
-.IX Item "-Ym,dir"
-Look in the directory \fIdir\fR to find the M4 preprocessor.
-The assembler uses this option.
-.PP
-.I "TMS320C3x/C4x Options"
-.IX Subsection "TMS320C3x/C4x Options"
-.PP
-These \fB\-m\fR options are defined for TMS320C3x/C4x implementations:
-.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4
-.IX Item "-mcpu=cpu_type"
-Set the instruction set, register set, and instruction scheduling
-parameters for machine type \fIcpu_type\fR. Supported values for
-\&\fIcpu_type\fR are \fBc30\fR, \fBc31\fR, \fBc32\fR, \fBc40\fR, and
-\&\fBc44\fR. The default is \fBc40\fR to generate code for the
-\&\s-1TMS320C40\s0.
-.Ip "\fB\-mbig-memory\fR" 4
-.IX Item "-mbig-memory"
-.PD 0
-.Ip "\fB\-mbig\fR" 4
-.IX Item "-mbig"
-.Ip "\fB\-msmall-memory\fR" 4
-.IX Item "-msmall-memory"
-.Ip "\fB\-msmall\fR" 4
-.IX Item "-msmall"
-.PD
-Generates code for the big or small memory model. The small memory
-model assumed that all data fits into one 64K word page. At run-time
-the data page (\s-1DP\s0) register must be set to point to the 64K page
-containing the .bss and .data program sections. The big memory model is
-the default and requires reloading of the \s-1DP\s0 register for every direct
-memory access.
-.Ip "\fB\-mbk\fR" 4
-.IX Item "-mbk"
-.PD 0
-.Ip "\fB\-mno-bk\fR" 4
-.IX Item "-mno-bk"
-.PD
-Allow (disallow) allocation of general integer operands into the block
-count register \s-1BK\s0.
-.Ip "\fB\-mdb\fR" 4
-.IX Item "-mdb"
-.PD 0
-.Ip "\fB\-mno-db\fR" 4
-.IX Item "-mno-db"
-.PD
-Enable (disable) generation of code using decrement and branch,
-DBcond(D), instructions. This is enabled by default for the C4x. To be
-on the safe side, this is disabled for the C3x, since the maximum
-iteration count on the C3x is 2^23 + 1 (but who iterates loops more than
-2^23 times on the C3x?). Note that \s-1GCC\s0 will try to reverse a loop so
-that it can utilise the decrement and branch instruction, but will give
-up if there is more than one memory reference in the loop. Thus a loop
-where the loop counter is decremented can generate slightly more
-efficient code, in cases where the \s-1RPTB\s0 instruction cannot be utilised.
-.Ip "\fB\-mdp-isr-reload\fR" 4
-.IX Item "-mdp-isr-reload"
-.PD 0
-.Ip "\fB\-mparanoid\fR" 4
-.IX Item "-mparanoid"
-.PD
-Force the \s-1DP\s0 register to be saved on entry to an interrupt service
-routine (\s-1ISR\s0), reloaded to point to the data section, and restored on
-exit from the \s-1ISR\s0. This should not be required unless someone has
-violated the small memory model by modifying the \s-1DP\s0 register, say within
-an object library.
-.Ip "\fB\-mmpyi\fR" 4
-.IX Item "-mmpyi"
-.PD 0
-.Ip "\fB\-mno-mpyi\fR" 4
-.IX Item "-mno-mpyi"
-.PD
-For the C3x use the 24\-bit \s-1MPYI\s0 instruction for integer multiplies
-instead of a library call to guarantee 32\-bit results. Note that if one
-of the operands is a constant, then the multiplication will be performed
-using shifts and adds. If the \fB\-mmpyi\fR option is not specified for the C3x,
-then squaring operations are performed inline instead of a library call.
-.Ip "\fB\-mfast-fix\fR" 4
-.IX Item "-mfast-fix"
-.PD 0
-.Ip "\fB\-mno-fast-fix\fR" 4
-.IX Item "-mno-fast-fix"
-.PD
-The C3x/C4x \s-1FIX\s0 instruction to convert a floating point value to an
-integer value chooses the nearest integer less than or equal to the
-floating point value rather than to the nearest integer. Thus if the
-floating point number is negative, the result will be incorrectly
-truncated an additional code is necessary to detect and correct this
-case. This option can be used to disable generation of the additional
-code required to correct the result.
-.Ip "\fB\-mrptb\fR" 4
-.IX Item "-mrptb"
-.PD 0
-.Ip "\fB\-mno-rptb\fR" 4
-.IX Item "-mno-rptb"
-.PD
-Enable (disable) generation of repeat block sequences using the \s-1RPTB\s0
-instruction for zero overhead looping. The \s-1RPTB\s0 construct is only used
-for innermost loops that do not call functions or jump across the loop
-boundaries. There is no advantage having nested \s-1RPTB\s0 loops due to the
-overhead required to save and restore the \s-1RC\s0, \s-1RS\s0, and \s-1RE\s0 registers.
-This is enabled by default with \fB\-O2\fR.
-.Ip "\fB\-mrpts=\fR\fIcount\fR" 4
-.IX Item "-mrpts=count"
-.PD 0
-.Ip "\fB\-mno-rpts\fR" 4
-.IX Item "-mno-rpts"
-.PD
-Enable (disable) the use of the single instruction repeat instruction
-\&\s-1RPTS\s0. If a repeat block contains a single instruction, and the loop
-count can be guaranteed to be less than the value \fIcount\fR, \s-1GCC\s0 will
-emit a \s-1RPTS\s0 instruction instead of a \s-1RPTB\s0. If no value is specified,
-then a \s-1RPTS\s0 will be emitted even if the loop count cannot be determined
-at compile time. Note that the repeated instruction following \s-1RPTS\s0 does
-not have to be reloaded from memory each iteration, thus freeing up the
-\&\s-1CPU\s0 buses for operands. However, since interrupts are blocked by this
-instruction, it is disabled by default.
-.Ip "\fB\-mloop-unsigned\fR" 4
-.IX Item "-mloop-unsigned"
-.PD 0
-.Ip "\fB\-mno-loop-unsigned\fR" 4
-.IX Item "-mno-loop-unsigned"
-.PD
-The maximum iteration count when using \s-1RPTS\s0 and \s-1RPTB\s0 (and \s-1DB\s0 on the C40)
-is 2^31 + 1 since these instructions test if the iteration count is
-negative to terminate the loop. If the iteration count is unsigned
-there is a possibility than the 2^31 + 1 maximum iteration count may be
-exceeded. This switch allows an unsigned iteration count.
-.Ip "\fB\-mti\fR" 4
-.IX Item "-mti"
-Try to emit an assembler syntax that the \s-1TI\s0 assembler (asm30) is happy
-with. This also enforces compatibility with the \s-1API\s0 employed by the \s-1TI\s0
-C3x C compiler. For example, long doubles are passed as structures
-rather than in floating point registers.
-.Ip "\fB\-mregparm\fR" 4
-.IX Item "-mregparm"
-.PD 0
-.Ip "\fB\-mmemparm\fR" 4
-.IX Item "-mmemparm"
-.PD
-Generate code that uses registers (stack) for passing arguments to functions.
-By default, arguments are passed in registers where possible rather
-than by pushing arguments on to the stack.
-.Ip "\fB\-mparallel-insns\fR" 4
-.IX Item "-mparallel-insns"
-.PD 0
-.Ip "\fB\-mno-parallel-insns\fR" 4
-.IX Item "-mno-parallel-insns"
-.PD
-Allow the generation of parallel instructions. This is enabled by
-default with \fB\-O2\fR.
-.Ip "\fB\-mparallel-mpy\fR" 4
-.IX Item "-mparallel-mpy"
-.PD 0
-.Ip "\fB\-mno-parallel-mpy\fR" 4
-.IX Item "-mno-parallel-mpy"
-.PD
-Allow the generation of MPY||ADD and MPY||SUB parallel instructions,
-provided \fB\-mparallel-insns\fR is also specified. These instructions have
-tight register constraints which can pessimize the code generation
-of large functions.
-.PP
-.I "V850 Options"
-.IX Subsection "V850 Options"
-.PP
-These \fB\-m\fR options are defined for V850 implementations:
-.Ip "\fB\-mlong-calls\fR" 4
-.IX Item "-mlong-calls"
-.PD 0
-.Ip "\fB\-mno-long-calls\fR" 4
-.IX Item "-mno-long-calls"
-.PD
-Treat all calls as being far away (near). If calls are assumed to be
-far away, the compiler will always load the functions address up into a
-register, and call indirect through the pointer.
-.Ip "\fB\-mno-ep\fR" 4
-.IX Item "-mno-ep"
-.PD 0
-.Ip "\fB\-mep\fR" 4
-.IX Item "-mep"
-.PD
-Do not optimize (do optimize) basic blocks that use the same index
-pointer 4 or more times to copy pointer into the \f(CW\*(C`ep\*(C'\fR register, and
-use the shorter \f(CW\*(C`sld\*(C'\fR and \f(CW\*(C`sst\*(C'\fR instructions. The \fB\-mep\fR
-option is on by default if you optimize.
-.Ip "\fB\-mno-prolog-function\fR" 4
-.IX Item "-mno-prolog-function"
-.PD 0
-.Ip "\fB\-mprolog-function\fR" 4
-.IX Item "-mprolog-function"
-.PD
-Do not use (do use) external functions to save and restore registers at
-the prolog and epilog of a function. The external functions are slower,
-but use less code space if more than one function saves the same number
-of registers. The \fB\-mprolog-function\fR option is on by default if
-you optimize.
-.Ip "\fB\-mspace\fR" 4
-.IX Item "-mspace"
-Try to make the code as small as possible. At present, this just turns
-on the \fB\-mep\fR and \fB\-mprolog-function\fR options.
-.Ip "\fB\-mtda=\fR\fIn\fR" 4
-.IX Item "-mtda=n"
-Put static or global variables whose size is \fIn\fR bytes or less into
-the tiny data area that register \f(CW\*(C`ep\*(C'\fR points to. The tiny data
-area can hold up to 256 bytes in total (128 bytes for byte references).
-.Ip "\fB\-msda=\fR\fIn\fR" 4
-.IX Item "-msda=n"
-Put static or global variables whose size is \fIn\fR bytes or less into
-the small data area that register \f(CW\*(C`gp\*(C'\fR points to. The small data
-area can hold up to 64 kilobytes.
-.Ip "\fB\-mzda=\fR\fIn\fR" 4
-.IX Item "-mzda=n"
-Put static or global variables whose size is \fIn\fR bytes or less into
-the first 32 kilobytes of memory.
-.Ip "\fB\-mv850\fR" 4
-.IX Item "-mv850"
-Specify that the target processor is the V850.
-.Ip "\fB\-mbig-switch\fR" 4
-.IX Item "-mbig-switch"
-Generate code suitable for big switch tables. Use this option only if
-the assembler/linker complain about out of range branches within a switch
-table.
-.PP
-.I "\s-1ARC\s0 Options"
-.IX Subsection "ARC Options"
-.PP
-These options are defined for \s-1ARC\s0 implementations:
-.Ip "\fB\-EL\fR" 4
-.IX Item "-EL"
-Compile code for little endian mode. This is the default.
-.Ip "\fB\-EB\fR" 4
-.IX Item "-EB"
-Compile code for big endian mode.
-.Ip "\fB\-mmangle-cpu\fR" 4
-.IX Item "-mmangle-cpu"
-Prepend the name of the cpu to all public symbol names.
-In multiple-processor systems, there are many \s-1ARC\s0 variants with different
-instruction and register set characteristics. This flag prevents code
-compiled for one cpu to be linked with code compiled for another.
-No facility exists for handling variants that are ``almost identical''.
-This is an all or nothing option.
-.Ip "\fB\-mcpu=\fR\fIcpu\fR" 4
-.IX Item "-mcpu=cpu"
-Compile code for \s-1ARC\s0 variant \fIcpu\fR.
-Which variants are supported depend on the configuration.
-All variants support \fB\-mcpu=base\fR, this is the default.
-.Ip "\fB\-mtext=\fR\fItext-section\fR" 4
-.IX Item "-mtext=text-section"
-.PD 0
-.Ip "\fB\-mdata=\fR\fIdata-section\fR" 4
-.IX Item "-mdata=data-section"
-.Ip "\fB\-mrodata=\fR\fIreadonly-data-section\fR" 4
-.IX Item "-mrodata=readonly-data-section"
-.PD
-Put functions, data, and readonly data in \fItext-section\fR,
-\&\fIdata-section\fR, and \fIreadonly-data-section\fR respectively
-by default. This can be overridden with the \f(CW\*(C`section\*(C'\fR attribute.
-.PP
-.I "\s-1NS32K\s0 Options"
-.IX Subsection "NS32K Options"
-.PP
-These are the \fB\-m\fR options defined for the 32000 series. The default
-values for these options depends on which style of 32000 was selected when
-the compiler was configured; the defaults for the most common choices are
-given below.
-.Ip "\fB\-m32032\fR" 4
-.IX Item "-m32032"
-.PD 0
-.Ip "\fB\-m32032\fR" 4
-.IX Item "-m32032"
-.PD
-Generate output for a 32032. This is the default
-when the compiler is configured for 32032 and 32016 based systems.
-.Ip "\fB\-m32332\fR" 4
-.IX Item "-m32332"
-.PD 0
-.Ip "\fB\-m32332\fR" 4
-.IX Item "-m32332"
-.PD
-Generate output for a 32332. This is the default
-when the compiler is configured for 32332\-based systems.
-.Ip "\fB\-m32532\fR" 4
-.IX Item "-m32532"
-.PD 0
-.Ip "\fB\-m32532\fR" 4
-.IX Item "-m32532"
-.PD
-Generate output for a 32532. This is the default
-when the compiler is configured for 32532\-based systems.
-.Ip "\fB\-m32081\fR" 4
-.IX Item "-m32081"
-Generate output containing 32081 instructions for floating point.
-This is the default for all systems.
-.Ip "\fB\-m32381\fR" 4
-.IX Item "-m32381"
-Generate output containing 32381 instructions for floating point. This
-also implies \fB\-m32081\fR. The 32381 is only compatible with the 32332
-and 32532 cpus. This is the default for the pc532\-netbsd configuration.
-.Ip "\fB\-mmulti-add\fR" 4
-.IX Item "-mmulti-add"
-Try and generate multiply-add floating point instructions \f(CW\*(C`polyF\*(C'\fR
-and \f(CW\*(C`dotF\*(C'\fR. This option is only available if the \fB\-m32381\fR
-option is in effect. Using these instructions requires changes to to
-register allocation which generally has a negative impact on
-performance. This option should only be enabled when compiling code
-particularly likely to make heavy use of multiply-add instructions.
-.Ip "\fB\-mnomulti-add\fR" 4
-.IX Item "-mnomulti-add"
-Do not try and generate multiply-add floating point instructions
-\&\f(CW\*(C`polyF\*(C'\fR and \f(CW\*(C`dotF\*(C'\fR. This is the default on all platforms.
-.Ip "\fB\-msoft-float\fR" 4
-.IX Item "-msoft-float"
-Generate output containing library calls for floating point.
-\&\fBWarning:\fR the requisite libraries may not be available.
-.Ip "\fB\-mnobitfield\fR" 4
-.IX Item "-mnobitfield"
-Do not use the bit-field instructions. On some machines it is faster to
-use shifting and masking operations. This is the default for the pc532.
-.Ip "\fB\-mbitfield\fR" 4
-.IX Item "-mbitfield"
-Do use the bit-field instructions. This is the default for all platforms
-except the pc532.
-.Ip "\fB\-mrtd\fR" 4
-.IX Item "-mrtd"
-Use a different function-calling convention, in which functions
-that take a fixed number of arguments return pop their
-arguments on return with the \f(CW\*(C`ret\*(C'\fR instruction.
-.Sp
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
-.Sp
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR);
-otherwise incorrect code will be generated for calls to those
-functions.
-.Sp
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
-.Sp
-This option takes its name from the 680x0 \f(CW\*(C`rtd\*(C'\fR instruction.
-.Ip "\fB\-mregparam\fR" 4
-.IX Item "-mregparam"
-Use a different function-calling convention where the first two arguments
-are passed in registers.
-.Sp
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
-.Ip "\fB\-mnoregparam\fR" 4
-.IX Item "-mnoregparam"
-Do not pass any arguments in registers. This is the default for all
-targets.
-.Ip "\fB\-msb\fR" 4
-.IX Item "-msb"
-It is \s-1OK\s0 to use the sb as an index register which is always loaded with
-zero. This is the default for the pc532\-netbsd target.
-.Ip "\fB\-mnosb\fR" 4
-.IX Item "-mnosb"
-The sb register is not available for use or has not been initialized to
-zero by the run time system. This is the default for all targets except
-the pc532\-netbsd. It is also implied whenever \fB\-mhimem\fR or
-\&\fB\-fpic\fR is set.
-.Ip "\fB\-mhimem\fR" 4
-.IX Item "-mhimem"
-Many ns32000 series addressing modes use displacements of up to 512MB.
-If an address is above 512MB then displacements from zero can not be used.
-This option causes code to be generated which can be loaded above 512MB.
-This may be useful for operating systems or \s-1ROM\s0 code.
-.Ip "\fB\-mnohimem\fR" 4
-.IX Item "-mnohimem"
-Assume code will be loaded in the first 512MB of virtual address space.
-This is the default for all platforms.
-.PP
-.I "\s-1AVR\s0 Options"
-.IX Subsection "AVR Options"
-.PP
-These options are defined for \s-1AVR\s0 implementations:
-.Ip "\fB\-mmcu=\fR\fImcu\fR" 4
-.IX Item "-mmcu=mcu"
-Specify \s-1ATMEL\s0 \s-1AVR\s0 instruction set or \s-1MCU\s0 type.
-.Sp
-Instruction set avr1 is for the minimal \s-1AVR\s0 core, not supported by the C
-compiler, only for assembler programs (\s-1MCU\s0 types: at90s1200, attiny10,
-attiny11, attiny12, attiny15, attiny28).
-.Sp
-Instruction set avr2 (default) is for the classic \s-1AVR\s0 core with up to
-8K program memory space (\s-1MCU\s0 types: at90s2313, at90s2323, attiny22,
-at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515,
-at90c8534, at90s8535).
-.Sp
-Instruction set avr3 is for the classic \s-1AVR\s0 core with up to 128K program
-memory space (\s-1MCU\s0 types: atmega103, atmega603).
-.Sp
-Instruction set avr4 is for the enhanced \s-1AVR\s0 core with up to 8K program
-memory space (\s-1MCU\s0 types: atmega83, atmega85).
-.Sp
-Instruction set avr5 is for the enhanced \s-1AVR\s0 core with up to 128K program
-memory space (\s-1MCU\s0 types: atmega161, atmega163, atmega32, at94k).
-.Ip "\fB\-msize\fR" 4
-.IX Item "-msize"
-Output instruction sizes to the asm file.
-.Ip "\fB\-minit-stack=\fR\fIN\fR" 4
-.IX Item "-minit-stack=N"
-Specify the initial stack address, which may be a symbol or numeric value,
-_\|_stack is the default.
-.Ip "\fB\-mno-interrupts\fR" 4
-.IX Item "-mno-interrupts"
-Generated code is not compatible with hardware interrupts.
-Code size will be smaller.
-.Ip "\fB\-mcall-prologues\fR" 4
-.IX Item "-mcall-prologues"
-Functions prologues/epilogues expanded as call to appropriate
-subroutines. Code size will be smaller.
-.Ip "\fB\-mno-tablejump\fR" 4
-.IX Item "-mno-tablejump"
-Do not generate tablejump insns which sometimes increase code size.
-.Ip "\fB\-mtiny-stack\fR" 4
-.IX Item "-mtiny-stack"
-Change only the low 8 bits of the stack pointer.
-.PP
-.I "MCore Options"
-.IX Subsection "MCore Options"
-.PP
-These are the \fB\-m\fR options defined for the Motorola M*Core
-processors.
-.Ip "\fB\-mhardlit\fR" 4
-.IX Item "-mhardlit"
-.PD 0
-.Ip "\fB\-mhardlit\fR" 4
-.IX Item "-mhardlit"
-.Ip "\fB\-mno-hardlit\fR" 4
-.IX Item "-mno-hardlit"
-.PD
-Inline constants into the code stream if it can be done in two
-instructions or less.
-.Ip "\fB\-mdiv\fR" 4
-.IX Item "-mdiv"
-.PD 0
-.Ip "\fB\-mdiv\fR" 4
-.IX Item "-mdiv"
-.Ip "\fB\-mno-div\fR" 4
-.IX Item "-mno-div"
-.PD
-Use the divide instruction. (Enabled by default).
-.Ip "\fB\-mrelax-immediate\fR" 4
-.IX Item "-mrelax-immediate"
-.PD 0
-.Ip "\fB\-mrelax-immediate\fR" 4
-.IX Item "-mrelax-immediate"
-.Ip "\fB\-mno-relax-immediate\fR" 4
-.IX Item "-mno-relax-immediate"
-.PD
-Allow arbitrary sized immediates in bit operations.
-.Ip "\fB\-mwide-bitfields\fR" 4
-.IX Item "-mwide-bitfields"
-.PD 0
-.Ip "\fB\-mwide-bitfields\fR" 4
-.IX Item "-mwide-bitfields"
-.Ip "\fB\-mno-wide-bitfields\fR" 4
-.IX Item "-mno-wide-bitfields"
-.PD
-Always treat bit-fields as int-sized.
-.Ip "\fB\-m4byte-functions\fR" 4
-.IX Item "-m4byte-functions"
-.PD 0
-.Ip "\fB\-m4byte-functions\fR" 4
-.IX Item "-m4byte-functions"
-.Ip "\fB\-mno-4byte-functions\fR" 4
-.IX Item "-mno-4byte-functions"
-.PD
-Force all functions to be aligned to a four byte boundary.
-.Ip "\fB\-mcallgraph-data\fR" 4
-.IX Item "-mcallgraph-data"
-.PD 0
-.Ip "\fB\-mcallgraph-data\fR" 4
-.IX Item "-mcallgraph-data"
-.Ip "\fB\-mno-callgraph-data\fR" 4
-.IX Item "-mno-callgraph-data"
-.PD
-Emit callgraph information.
-.Ip "\fB\-mslow-bytes\fR" 4
-.IX Item "-mslow-bytes"
-.PD 0
-.Ip "\fB\-mslow-bytes\fR" 4
-.IX Item "-mslow-bytes"
-.Ip "\fB\-mno-slow-bytes\fR" 4
-.IX Item "-mno-slow-bytes"
-.PD
-Prefer word access when reading byte quantities.
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-.PD 0
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-.Ip "\fB\-mbig-endian\fR" 4
-.IX Item "-mbig-endian"
-.PD
-Generate code for a little endian target.
-.Ip "\fB\-m210\fR" 4
-.IX Item "-m210"
-.PD 0
-.Ip "\fB\-m210\fR" 4
-.IX Item "-m210"
-.Ip "\fB\-m340\fR" 4
-.IX Item "-m340"
-.PD
-Generate code for the 210 processor.
-.PP
-.I "\s-1IA-64\s0 Options"
-.IX Subsection "IA-64 Options"
-.PP
-These are the \fB\-m\fR options defined for the Intel \s-1IA-64\s0 architecture.
-.Ip "\fB\-mbig-endian\fR" 4
-.IX Item "-mbig-endian"
-Generate code for a big endian target. This is the default for \s-1HPUX\s0.
-.Ip "\fB\-mlittle-endian\fR" 4
-.IX Item "-mlittle-endian"
-Generate code for a little endian target. This is the default for \s-1AIX5\s0
-and Linux.
-.Ip "\fB\-mgnu-as\fR" 4
-.IX Item "-mgnu-as"
-.PD 0
-.Ip "\fB\-mno-gnu-as\fR" 4
-.IX Item "-mno-gnu-as"
-.PD
-Generate (or don't) code for the \s-1GNU\s0 assembler. This is the default.
-.Ip "\fB\-mgnu-ld\fR" 4
-.IX Item "-mgnu-ld"
-.PD 0
-.Ip "\fB\-mno-gnu-ld\fR" 4
-.IX Item "-mno-gnu-ld"
-.PD
-Generate (or don't) code for the \s-1GNU\s0 linker. This is the default.
-.Ip "\fB\-mno-pic\fR" 4
-.IX Item "-mno-pic"
-Generate code that does not use a global pointer register. The result
-is not position independent code, and violates the \s-1IA-64\s0 \s-1ABI\s0.
-.Ip "\fB\-mvolatile-asm-stop\fR" 4
-.IX Item "-mvolatile-asm-stop"
-.PD 0
-.Ip "\fB\-mno-volatile-asm-stop\fR" 4
-.IX Item "-mno-volatile-asm-stop"
-.PD
-Generate (or don't) a stop bit immediately before and after volatile asm
-statements.
-.Ip "\fB\-mb-step\fR" 4
-.IX Item "-mb-step"
-Generate code that works around Itanium B step errata.
-.Ip "\fB\-mregister-names\fR" 4
-.IX Item "-mregister-names"
-.PD 0
-.Ip "\fB\-mno-register-names\fR" 4
-.IX Item "-mno-register-names"
-.PD
-Generate (or don't) \fBin\fR, \fBloc\fR, and \fBout\fR register names for
-the stacked registers. This may make assembler output more readable.
-.Ip "\fB\-mno-sdata\fR" 4
-.IX Item "-mno-sdata"
-.PD 0
-.Ip "\fB\-msdata\fR" 4
-.IX Item "-msdata"
-.PD
-Disable (or enable) optimizations that use the small data section. This may
-be useful for working around optimizer bugs.
-.Ip "\fB\-mconstant-gp\fR" 4
-.IX Item "-mconstant-gp"
-Generate code that uses a single constant global pointer value. This is
-useful when compiling kernel code.
-.Ip "\fB\-mauto-pic\fR" 4
-.IX Item "-mauto-pic"
-Generate code that is self-relocatable. This implies \fB\-mconstant-gp\fR.
-This is useful when compiling firmware code.
-.Ip "\fB\-minline-divide-min-latency\fR" 4
-.IX Item "-minline-divide-min-latency"
-Generate code for inline divides using the minimum latency algorithm.
-.Ip "\fB\-minline-divide-max-throughput\fR" 4
-.IX Item "-minline-divide-max-throughput"
-Generate code for inline divides using the maximum throughput algorithm.
-.Ip "\fB\-mno-dwarf2\-asm\fR" 4
-.IX Item "-mno-dwarf2-asm"
-.PD 0
-.Ip "\fB\-mdwarf2\-asm\fR" 4
-.IX Item "-mdwarf2-asm"
-.PD
-Don't (or do) generate assembler code for the \s-1DWARF2\s0 line number debugging
-info. This may be useful when not using the \s-1GNU\s0 assembler.
-.Ip "\fB\-mfixed-range=\fR\fIregister-range\fR" 4
-.IX Item "-mfixed-range=register-range"
-Generate code treating the given register range as fixed registers.
-A fixed register is one that the register allocator can not use. This is
-useful when compiling kernel code. A register range is specified as
-two registers separated by a dash. Multiple register ranges can be
-specified separated by a comma.
-.PP
-.I "D30V Options"
-.IX Subsection "D30V Options"
-.PP
-These \fB\-m\fR options are defined for D30V implementations:
-.Ip "\fB\-mextmem\fR" 4
-.IX Item "-mextmem"
-Link the \fB.text\fR, \fB.data\fR, \fB.bss\fR, \fB.strings\fR,
-\&\fB.rodata\fR, \fB.rodata1\fR, \fB.data1\fR sections into external
-memory, which starts at location \f(CW\*(C`0x80000000\*(C'\fR.
-.Ip "\fB\-mextmemory\fR" 4
-.IX Item "-mextmemory"
-Same as the \fB\-mextmem\fR switch.
-.Ip "\fB\-monchip\fR" 4
-.IX Item "-monchip"
-Link the \fB.text\fR section into onchip text memory, which starts at
-location \f(CW\*(C`0x0\*(C'\fR. Also link \fB.data\fR, \fB.bss\fR,
-\&\fB.strings\fR, \fB.rodata\fR, \fB.rodata1\fR, \fB.data1\fR sections
-into onchip data memory, which starts at location \f(CW\*(C`0x20000000\*(C'\fR.
-.Ip "\fB\-mno-asm-optimize\fR" 4
-.IX Item "-mno-asm-optimize"
-.PD 0
-.Ip "\fB\-masm-optimize\fR" 4
-.IX Item "-masm-optimize"
-.PD
-Disable (enable) passing \fB\-O\fR to the assembler when optimizing.
-The assembler uses the \fB\-O\fR option to automatically parallelize
-adjacent short instructions where possible.
-.Ip "\fB\-mbranch-cost=\fR\fIn\fR" 4
-.IX Item "-mbranch-cost=n"
-Increase the internal costs of branches to \fIn\fR. Higher costs means
-that the compiler will issue more instructions to avoid doing a branch.
-The default is 2.
-.Ip "\fB\-mcond-exec=\fR\fIn\fR" 4
-.IX Item "-mcond-exec=n"
-Specify the maximum number of conditionally executed instructions that
-replace a branch. The default is 4.
-.Sh "Options for Code Generation Conventions"
-.IX Subsection "Options for Code Generation Conventions"
-These machine-independent options control the interface conventions
-used in code generation.
-.PP
-Most of them have both positive and negative forms; the negative form
-of \fB\-ffoo\fR would be \fB\-fno-foo\fR. In the table below, only
-one of the forms is listed\-\-\-the one which is not the default. You
-can figure out the other form by either removing \fBno-\fR or adding
-it.
-.Ip "\fB\-fexceptions\fR" 4
-.IX Item "-fexceptions"
-Enable exception handling. Generates extra code needed to propagate
-exceptions. For some targets, this implies \s-1GCC\s0 will generate frame
-unwind information for all functions, which can produce significant data
-size overhead, although it does not affect execution. If you do not
-specify this option, \s-1GCC\s0 will enable it by default for languages like
-\&\*(C+ which normally require exception handling, and disable it for
-languages like C that do not normally require it. However, you may need
-to enable this option when compiling C code that needs to interoperate
-properly with exception handlers written in \*(C+. You may also wish to
-disable this option if you are compiling older \*(C+ programs that don't
-use exception handling.
-.Ip "\fB\-fnon-call-exceptions\fR" 4
-.IX Item "-fnon-call-exceptions"
-Generate code that allows trapping instructions to throw exceptions.
-Note that this requires platform-specific runtime support that does
-not exist everywhere. Moreover, it only allows \fItrapping\fR
-instructions to throw exceptions, i.e. memory references or floating
-point instructions. It does not allow exceptions to be thrown from
-arbitrary signal handlers such as \f(CW\*(C`SIGALRM\*(C'\fR.
-.Ip "\fB\-funwind-tables\fR" 4
-.IX Item "-funwind-tables"
-Similar to \fB\-fexceptions\fR, except that it will just generate any needed
-static data, but will not affect the generated code in any other way.
-You will normally not enable this option; instead, a language processor
-that needs this handling would enable it on your behalf.
-.Ip "\fB\-fpcc-struct-return\fR" 4
-.IX Item "-fpcc-struct-return"
-Return ``short'' \f(CW\*(C`struct\*(C'\fR and \f(CW\*(C`union\*(C'\fR values in memory like
-longer ones, rather than in registers. This convention is less
-efficient, but it has the advantage of allowing intercallability between
-GCC-compiled files and files compiled with other compilers.
-.Sp
-The precise convention for returning structures in memory depends
-on the target configuration macros.
-.Sp
-Short structures and unions are those whose size and alignment match
-that of some integer type.
-.Ip "\fB\-freg-struct-return\fR" 4
-.IX Item "-freg-struct-return"
-Use the convention that \f(CW\*(C`struct\*(C'\fR and \f(CW\*(C`union\*(C'\fR values are
-returned in registers when possible. This is more efficient for small
-structures than \fB\-fpcc-struct-return\fR.
-.Sp
-If you specify neither \fB\-fpcc-struct-return\fR nor its contrary
-\&\fB\-freg-struct-return\fR, \s-1GCC\s0 defaults to whichever convention is
-standard for the target. If there is no standard convention, \s-1GCC\s0
-defaults to \fB\-fpcc-struct-return\fR, except on targets where \s-1GCC\s0
-is the principal compiler. In those cases, we can choose the standard,
-and we chose the more efficient register return alternative.
-.Ip "\fB\-fshort-enums\fR" 4
-.IX Item "-fshort-enums"
-Allocate to an \f(CW\*(C`enum\*(C'\fR type only as many bytes as it needs for the
-declared range of possible values. Specifically, the \f(CW\*(C`enum\*(C'\fR type
-will be equivalent to the smallest integer type which has enough room.
-.Ip "\fB\-fshort-double\fR" 4
-.IX Item "-fshort-double"
-Use the same size for \f(CW\*(C`double\*(C'\fR as for \f(CW\*(C`float\*(C'\fR.
-.Ip "\fB\-fshared-data\fR" 4
-.IX Item "-fshared-data"
-Requests that the data and non-\f(CW\*(C`const\*(C'\fR variables of this
-compilation be shared data rather than private data. The distinction
-makes sense only on certain operating systems, where shared data is
-shared between processes running the same program, while private data
-exists in one copy per process.
-.Ip "\fB\-fno-common\fR" 4
-.IX Item "-fno-common"
-In C, allocate even uninitialized global variables in the data section of the
-object file, rather than generating them as common blocks. This has the
-effect that if the same variable is declared (without \f(CW\*(C`extern\*(C'\fR) in
-two different compilations, you will get an error when you link them.
-The only reason this might be useful is if you wish to verify that the
-program will work on other systems which always work this way.
-.Ip "\fB\-fno-ident\fR" 4
-.IX Item "-fno-ident"
-Ignore the \fB#ident\fR directive.
-.Ip "\fB\-fno-gnu-linker\fR" 4
-.IX Item "-fno-gnu-linker"
-Do not output global initializations (such as \*(C+ constructors and
-destructors) in the form used by the \s-1GNU\s0 linker (on systems where the \s-1GNU\s0
-linker is the standard method of handling them). Use this option when
-you want to use a non-GNU linker, which also requires using the
-\&\fBcollect2\fR program to make sure the system linker includes
-constructors and destructors. (\fBcollect2\fR is included in the \s-1GCC\s0
-distribution.) For systems which \fImust\fR use \fBcollect2\fR, the
-compiler driver \fBgcc\fR is configured to do this automatically.
-.Ip "\fB\-finhibit-size-directive\fR" 4
-.IX Item "-finhibit-size-directive"
-Don't output a \f(CW\*(C`.size\*(C'\fR assembler directive, or anything else that
-would cause trouble if the function is split in the middle, and the
-two halves are placed at locations far apart in memory. This option is
-used when compiling \fIcrtstuff.c\fR; you should not need to use it
-for anything else.
-.Ip "\fB\-fverbose-asm\fR" 4
-.IX Item "-fverbose-asm"
-Put extra commentary information in the generated assembly code to
-make it more readable. This option is generally only of use to those
-who actually need to read the generated assembly code (perhaps while
-debugging the compiler itself).
-.Sp
-\&\fB\-fno-verbose-asm\fR, the default, causes the
-extra information to be omitted and is useful when comparing two assembler
-files.
-.Ip "\fB\-fvolatile\fR" 4
-.IX Item "-fvolatile"
-Consider all memory references through pointers to be volatile.
-.Ip "\fB\-fvolatile-global\fR" 4
-.IX Item "-fvolatile-global"
-Consider all memory references to extern and global data items to
-be volatile. \s-1GCC\s0 does not consider static data items to be volatile
-because of this switch.
-.Ip "\fB\-fvolatile-static\fR" 4
-.IX Item "-fvolatile-static"
-Consider all memory references to static data to be volatile.
-.Ip "\fB\-fpic\fR" 4
-.IX Item "-fpic"
-Generate position-independent code (\s-1PIC\s0) suitable for use in a shared
-library, if supported for the target machine. Such code accesses all
-constant addresses through a global offset table (\s-1GOT\s0). The dynamic
-loader resolves the \s-1GOT\s0 entries when the program starts (the dynamic
-loader is not part of \s-1GCC\s0; it is part of the operating system). If
-the \s-1GOT\s0 size for the linked executable exceeds a machine-specific
-maximum size, you get an error message from the linker indicating that
-\&\fB\-fpic\fR does not work; in that case, recompile with \fB\-fPIC\fR
-instead. (These maximums are 16k on the m88k, 8k on the Sparc, and 32k
-on the m68k and \s-1RS/6000\s0. The 386 has no such limit.)
-.Sp
-Position-independent code requires special support, and therefore works
-only on certain machines. For the 386, \s-1GCC\s0 supports \s-1PIC\s0 for System V
-but not for the Sun 386i. Code generated for the \s-1IBM\s0 \s-1RS/6000\s0 is always
-position-independent.
-.Ip "\fB\-fPIC\fR" 4
-.IX Item "-fPIC"
-If supported for the target machine, emit position-independent code,
-suitable for dynamic linking and avoiding any limit on the size of the
-global offset table. This option makes a difference on the m68k, m88k,
-and the Sparc.
-.Sp
-Position-independent code requires special support, and therefore works
-only on certain machines.
-.Ip "\fB\-ffixed-\fR\fIreg\fR" 4
-.IX Item "-ffixed-reg"
-Treat the register named \fIreg\fR as a fixed register; generated code
-should never refer to it (except perhaps as a stack pointer, frame
-pointer or in some other fixed role).
-.Sp
-\&\fIreg\fR must be the name of a register. The register names accepted
-are machine-specific and are defined in the \f(CW\*(C`REGISTER_NAMES\*(C'\fR
-macro in the machine description macro file.
-.Sp
-This flag does not have a negative form, because it specifies a
-three-way choice.
-.Ip "\fB\-fcall-used-\fR\fIreg\fR" 4
-.IX Item "-fcall-used-reg"
-Treat the register named \fIreg\fR as an allocable register that is
-clobbered by function calls. It may be allocated for temporaries or
-variables that do not live across a call. Functions compiled this way
-will not save and restore the register \fIreg\fR.
-.Sp
-It is an error to used this flag with the frame pointer or stack pointer.
-Use of this flag for other registers that have fixed pervasive roles in
-the machine's execution model will produce disastrous results.
-.Sp
-This flag does not have a negative form, because it specifies a
-three-way choice.
-.Ip "\fB\-fcall-saved-\fR\fIreg\fR" 4
-.IX Item "-fcall-saved-reg"
-Treat the register named \fIreg\fR as an allocable register saved by
-functions. It may be allocated even for temporaries or variables that
-live across a call. Functions compiled this way will save and restore
-the register \fIreg\fR if they use it.
-.Sp
-It is an error to used this flag with the frame pointer or stack pointer.
-Use of this flag for other registers that have fixed pervasive roles in
-the machine's execution model will produce disastrous results.
-.Sp
-A different sort of disaster will result from the use of this flag for
-a register in which function values may be returned.
-.Sp
-This flag does not have a negative form, because it specifies a
-three-way choice.
-.Ip "\fB\-fpack-struct\fR" 4
-.IX Item "-fpack-struct"
-Pack all structure members together without holes. Usually you would
-not want to use this option, since it makes the code suboptimal, and
-the offsets of structure members won't agree with system libraries.
-.Ip "\fB\-fcheck-memory-usage\fR" 4
-.IX Item "-fcheck-memory-usage"
-Generate extra code to check each memory access. \s-1GCC\s0 will generate
-code that is suitable for a detector of bad memory accesses such as
-\&\fIChecker\fR.
-.Sp
-Normally, you should compile all, or none, of your code with this option.
-.Sp
-If you do mix code compiled with and without this option,
-you must ensure that all code that has side effects
-and that is called by code compiled with this option
-is, itself, compiled with this option.
-If you do not, you might get erroneous messages from the detector.
-.Sp
-If you use functions from a library that have side-effects (such as
-\&\f(CW\*(C`read\*(C'\fR), you might not be able to recompile the library and
-specify this option. In that case, you can enable the
-\&\fB\-fprefix-function-name\fR option, which requests \s-1GCC\s0 to encapsulate
-your code and make other functions look as if they were compiled with
-\&\fB\-fcheck-memory-usage\fR. This is done by calling ``stubs'',
-which are provided by the detector. If you cannot find or build
-stubs for every function you call, you might have to specify
-\&\fB\-fcheck-memory-usage\fR without \fB\-fprefix-function-name\fR.
-.Sp
-If you specify this option, you can not use the \f(CW\*(C`asm\*(C'\fR or
-\&\f(CW\*(C`_\|_asm_\|_\*(C'\fR keywords in functions with memory checking enabled. \s-1GCC\s0
-cannot understand what the \f(CW\*(C`asm\*(C'\fR statement may do, and therefore
-cannot generate the appropriate code, so it will reject it. However, if
-you specify the function attribute \f(CW\*(C`no_check_memory_usage\*(C'\fR, \s-1GCC\s0 will disable memory checking within a
-function; you may use \f(CW\*(C`asm\*(C'\fR statements inside such functions. You
-may have an inline expansion of a non-checked function within a checked
-function; in that case \s-1GCC\s0 will not generate checks for the inlined
-function's memory accesses.
-.Sp
-If you move your \f(CW\*(C`asm\*(C'\fR statements to non-checked inline functions
-and they do access memory, you can add calls to the support code in your
-inline function, to indicate any reads, writes, or copies being done.
-These calls would be similar to those done in the stubs described above.
-.Ip "\fB\-fprefix-function-name\fR" 4
-.IX Item "-fprefix-function-name"
-Request \s-1GCC\s0 to add a prefix to the symbols generated for function names.
-\&\s-1GCC\s0 adds a prefix to the names of functions defined as well as
-functions called. Code compiled with this option and code compiled
-without the option can't be linked together, unless stubs are used.
-.Sp
-If you compile the following code with \fB\-fprefix-function-name\fR
-.Sp
-.Vb 6
-\& extern void bar (int);
-\& void
-\& foo (int a)
-\& {
-\& return bar (a + 5);
-\& }
-.Ve
-\&\s-1GCC\s0 will compile the code as if it was written:
-.Sp
-.Vb 6
-\& extern void prefix_bar (int);
-\& void
-\& prefix_foo (int a)
-\& {
-\& return prefix_bar (a + 5);
-\& }
-.Ve
-This option is designed to be used with \fB\-fcheck-memory-usage\fR.
-.Ip "\fB\-finstrument-functions\fR" 4
-.IX Item "-finstrument-functions"
-Generate instrumentation calls for entry and exit to functions. Just
-after function entry and just before function exit, the following
-profiling functions will be called with the address of the current
-function and its call site. (On some platforms,
-\&\f(CW\*(C`_\|_builtin_return_address\*(C'\fR does not work beyond the current
-function, so the call site information may not be available to the
-profiling functions otherwise.)
-.Sp
-.Vb 4
-\& void __cyg_profile_func_enter (void *this_fn,
-\& void *call_site);
-\& void __cyg_profile_func_exit (void *this_fn,
-\& void *call_site);
-.Ve
-The first argument is the address of the start of the current function,
-which may be looked up exactly in the symbol table.
-.Sp
-This instrumentation is also done for functions expanded inline in other
-functions. The profiling calls will indicate where, conceptually, the
-inline function is entered and exited. This means that addressable
-versions of such functions must be available. If all your uses of a
-function are expanded inline, this may mean an additional expansion of
-code size. If you use \fBextern inline\fR in your C code, an
-addressable version of such functions must be provided. (This is
-normally the case anyways, but if you get lucky and the optimizer always
-expands the functions inline, you might have gotten away without
-providing static copies.)
-.Sp
-A function may be given the attribute \f(CW\*(C`no_instrument_function\*(C'\fR, in
-which case this instrumentation will not be done. This can be used, for
-example, for the profiling functions listed above, high-priority
-interrupt routines, and any functions from which the profiling functions
-cannot safely be called (perhaps signal handlers, if the profiling
-routines generate output or allocate memory).
-.Ip "\fB\-fstack-check\fR" 4
-.IX Item "-fstack-check"
-Generate code to verify that you do not go beyond the boundary of the
-stack. You should specify this flag if you are running in an
-environment with multiple threads, but only rarely need to specify it in
-a single-threaded environment since stack overflow is automatically
-detected on nearly all systems if there is only one stack.
-.Sp
-Note that this switch does not actually cause checking to be done; the
-operating system must do that. The switch causes generation of code
-to ensure that the operating system sees the stack being extended.
-.Ip "\fB\-fstack-limit-register=\fR\fIreg\fR" 4
-.IX Item "-fstack-limit-register=reg"
-.PD 0
-.Ip "\fB\-fstack-limit-symbol=\fR\fIsym\fR" 4
-.IX Item "-fstack-limit-symbol=sym"
-.Ip "\fB\-fno-stack-limit\fR" 4
-.IX Item "-fno-stack-limit"
-.PD
-Generate code to ensure that the stack does not grow beyond a certain value,
-either the value of a register or the address of a symbol. If the stack
-would grow beyond the value, a signal is raised. For most targets,
-the signal is raised before the stack overruns the boundary, so
-it is possible to catch the signal without taking special precautions.
-.Sp
-For instance, if the stack starts at address \fB0x80000000\fR and grows
-downwards you can use the flags
-\&\fB\-fstack-limit-symbol=_\|_stack_limit
-\&\-Wl,\-\-defsym,_\|_stack_limit=0x7ffe0000\fR which will enforce a stack
-limit of 128K.
-.Ip "\fB\-fargument-alias\fR" 4
-.IX Item "-fargument-alias"
-.PD 0
-.Ip "\fB\-fargument-noalias\fR" 4
-.IX Item "-fargument-noalias"
-.Ip "\fB\-fargument-noalias-global\fR" 4
-.IX Item "-fargument-noalias-global"
-.PD
-Specify the possible relationships among parameters and between
-parameters and global data.
-.Sp
-\&\fB\-fargument-alias\fR specifies that arguments (parameters) may
-alias each other and may alias global storage.
-\&\fB\-fargument-noalias\fR specifies that arguments do not alias
-each other, but may alias global storage.
-\&\fB\-fargument-noalias-global\fR specifies that arguments do not
-alias each other and do not alias global storage.
-.Sp
-Each language will automatically use whatever option is required by
-the language standard. You should not need to use these options yourself.
-.Ip "\fB\-fleading-underscore\fR" 4
-.IX Item "-fleading-underscore"
-This option and its counterpart, \fB\-fno-leading-underscore\fR, forcibly
-change the way C symbols are represented in the object file. One use
-is to help link with legacy assembly code.
-.Sp
-Be warned that you should know what you are doing when invoking this
-option, and that not all targets provide complete support for it.
-.SH "ENVIRONMENT"
-.IX Header "ENVIRONMENT"
-This section describes several environment variables that affect how \s-1GCC\s0
-operates. Some of them work by specifying directories or prefixes to use
-when searching for various kinds of files. Some are used to specify other
-aspects of the compilation environment.
-.PP
-Note that you can also specify places to search using options such as
-\&\fB\-B\fR, \fB\-I\fR and \fB\-L\fR. These
-take precedence over places specified using environment variables, which
-in turn take precedence over those specified by the configuration of \s-1GCC\s0.
-.Ip "\fB\s-1LANG\s0\fR" 4
-.IX Item "LANG"
-.PD 0
-.Ip "\fB\s-1LC_CTYPE\s0\fR" 4
-.IX Item "LC_CTYPE"
-.Ip "\fB\s-1LC_MESSAGES\s0\fR" 4
-.IX Item "LC_MESSAGES"
-.Ip "\fB\s-1LC_ALL\s0\fR" 4
-.IX Item "LC_ALL"
-.PD
-These environment variables control the way that \s-1GCC\s0 uses
-localization information that allow \s-1GCC\s0 to work with different
-national conventions. \s-1GCC\s0 inspects the locale categories
-\&\fB\s-1LC_CTYPE\s0\fR and \fB\s-1LC_MESSAGES\s0\fR if it has been configured to do
-so. These locale categories can be set to any value supported by your
-installation. A typical value is \fBen_UK\fR for English in the United
-Kingdom.
-.Sp
-The \fB\s-1LC_CTYPE\s0\fR environment variable specifies character
-classification. \s-1GCC\s0 uses it to determine the character boundaries in
-a string; this is needed for some multibyte encodings that contain quote
-and escape characters that would otherwise be interpreted as a string
-end or escape.
-.Sp
-The \fB\s-1LC_MESSAGES\s0\fR environment variable specifies the language to
-use in diagnostic messages.
-.Sp
-If the \fB\s-1LC_ALL\s0\fR environment variable is set, it overrides the value
-of \fB\s-1LC_CTYPE\s0\fR and \fB\s-1LC_MESSAGES\s0\fR; otherwise, \fB\s-1LC_CTYPE\s0\fR
-and \fB\s-1LC_MESSAGES\s0\fR default to the value of the \fB\s-1LANG\s0\fR
-environment variable. If none of these variables are set, \s-1GCC\s0
-defaults to traditional C English behavior.
-.Ip "\fB\s-1TMPDIR\s0\fR" 4
-.IX Item "TMPDIR"
-If \fB\s-1TMPDIR\s0\fR is set, it specifies the directory to use for temporary
-files. \s-1GCC\s0 uses temporary files to hold the output of one stage of
-compilation which is to be used as input to the next stage: for example,
-the output of the preprocessor, which is the input to the compiler
-proper.
-.Ip "\fB\s-1GCC_EXEC_PREFIX\s0\fR" 4
-.IX Item "GCC_EXEC_PREFIX"
-If \fB\s-1GCC_EXEC_PREFIX\s0\fR is set, it specifies a prefix to use in the
-names of the subprograms executed by the compiler. No slash is added
-when this prefix is combined with the name of a subprogram, but you can
-specify a prefix that ends with a slash if you wish.
-.Sp
-If \fB\s-1GCC_EXEC_PREFIX\s0\fR is not set, \s-1GCC\s0 will attempt to figure out
-an appropriate prefix to use based on the pathname it was invoked with.
-.Sp
-If \s-1GCC\s0 cannot find the subprogram using the specified prefix, it
-tries looking in the usual places for the subprogram.
-.Sp
-The default value of \fB\s-1GCC_EXEC_PREFIX\s0\fR is
-\&\fI\fIprefix\fI/lib/gcc-lib/\fR where \fIprefix\fR is the value
-of \f(CW\*(C`prefix\*(C'\fR when you ran the \fIconfigure\fR script.
-.Sp
-Other prefixes specified with \fB\-B\fR take precedence over this prefix.
-.Sp
-This prefix is also used for finding files such as \fIcrt0.o\fR that are
-used for linking.
-.Sp
-In addition, the prefix is used in an unusual way in finding the
-directories to search for header files. For each of the standard
-directories whose name normally begins with \fB/usr/local/lib/gcc-lib\fR
-(more precisely, with the value of \fB\s-1GCC_INCLUDE_DIR\s0\fR), \s-1GCC\s0 tries
-replacing that beginning with the specified prefix to produce an
-alternate directory name. Thus, with \fB\-Bfoo/\fR, \s-1GCC\s0 will search
-\&\fIfoo/bar\fR where it would normally search \fI/usr/local/lib/bar\fR.
-These alternate directories are searched first; the standard directories
-come next.
-.Ip "\fB\s-1COMPILER_PATH\s0\fR" 4
-.IX Item "COMPILER_PATH"
-The value of \fB\s-1COMPILER_PATH\s0\fR is a colon-separated list of
-directories, much like \fB\s-1PATH\s0\fR. \s-1GCC\s0 tries the directories thus
-specified when searching for subprograms, if it can't find the
-subprograms using \fB\s-1GCC_EXEC_PREFIX\s0\fR.
-.Ip "\fB\s-1LIBRARY_PATH\s0\fR" 4
-.IX Item "LIBRARY_PATH"
-The value of \fB\s-1LIBRARY_PATH\s0\fR is a colon-separated list of
-directories, much like \fB\s-1PATH\s0\fR. When configured as a native compiler,
-\&\s-1GCC\s0 tries the directories thus specified when searching for special
-linker files, if it can't find them using \fB\s-1GCC_EXEC_PREFIX\s0\fR. Linking
-using \s-1GCC\s0 also uses these directories when searching for ordinary
-libraries for the \fB\-l\fR option (but directories specified with
-\&\fB\-L\fR come first).
-.Ip "\fBC_INCLUDE_PATH\fR" 4
-.IX Item "C_INCLUDE_PATH"
-.PD 0
-.Ip "\fB\s-1CPLUS_INCLUDE_PATH\s0\fR" 4
-.IX Item "CPLUS_INCLUDE_PATH"
-.Ip "\fB\s-1OBJC_INCLUDE_PATH\s0\fR" 4
-.IX Item "OBJC_INCLUDE_PATH"
-.PD
-These environment variables pertain to particular languages. Each
-variable's value is a colon-separated list of directories, much like
-\&\fB\s-1PATH\s0\fR. When \s-1GCC\s0 searches for header files, it tries the
-directories listed in the variable for the language you are using, after
-the directories specified with \fB\-I\fR but before the standard header
-file directories.
-.Ip "\fB\s-1DEPENDENCIES_OUTPUT\s0\fR" 4
-.IX Item "DEPENDENCIES_OUTPUT"
-If this variable is set, its value specifies how to output dependencies
-for Make based on the header files processed by the compiler. This
-output looks much like the output from the \fB\-M\fR option, but it goes to a separate file, and is
-in addition to the usual results of compilation.
-.Sp
-The value of \fB\s-1DEPENDENCIES_OUTPUT\s0\fR can be just a file name, in
-which case the Make rules are written to that file, guessing the target
-name from the source file name. Or the value can have the form
-\&\fIfile\fR\fB \fR\fItarget\fR, in which case the rules are written to
-file \fIfile\fR using \fItarget\fR as the target name.
-.Ip "\fB\s-1LANG\s0\fR" 4
-.IX Item "LANG"
-This variable is used to pass locale information to the compiler. One way in
-which this information is used is to determine the character set to be used
-when character literals, string literals and comments are parsed in C and \*(C+.
-When the compiler is configured to allow multibyte characters,
-the following values for \fB\s-1LANG\s0\fR are recognized:
-.RS 4
-.Ip "\fBC-JIS\fR" 4
-.IX Item "C-JIS"
-Recognize \s-1JIS\s0 characters.
-.Ip "\fBC-SJIS\fR" 4
-.IX Item "C-SJIS"
-Recognize \s-1SJIS\s0 characters.
-.Ip "\fBC-EUCJP\fR" 4
-.IX Item "C-EUCJP"
-Recognize \s-1EUCJP\s0 characters.
-.RE
-.RS 4
-.Sp
-If \fB\s-1LANG\s0\fR is not defined, or if it has some other value, then the
-compiler will use mblen and mbtowc as defined by the default locale to
-recognize and translate multibyte characters.
-.RE
-.SH "BUGS"
-.IX Header "BUGS"
-For instructions on reporting bugs, see
-<\fBhttp://gcc.gnu.org/bugs.html\fR>. Use of the \fBgccbug\fR
-script to report bugs is recommended.
-.SH "FOOTNOTES"
-.IX Header "FOOTNOTES"
-.Ip "1." 4
-On some systems, \fBgcc \-shared\fR
-needs to build supplementary stub code for constructors to work. On
-multi-libbed systems, \fBgcc \-shared\fR must select the correct support
-libraries to link against. Failing to supply the correct flags may lead
-to subtle defects. Supplying them in cases where they are not necessary
-is innocuous.
-.SH "SEE ALSO"
-.IX Header "SEE ALSO"
-\&\fIcpp\fR\|(1), \fIgcov\fR\|(1), \fIg77\fR\|(1), \fIas\fR\|(1), \fIld\fR\|(1), \fIgdb\fR\|(1), \fIadb\fR\|(1), \fIdbx\fR\|(1), \fIsdb\fR\|(1)
-and the Info entries for \fIgcc\fR, \fIcpp\fR, \fIg77\fR, \fIas\fR,
-\&\fIld\fR, \fIbinutils\fR and \fIgdb\fR.
-.SH "AUTHOR"
-.IX Header "AUTHOR"
-See the Info entry for \fIgcc\fR, or
-<\fBhttp://gcc.gnu.org/thanks.html\fR>, for contributors to \s-1GCC\s0.
-.SH "COPYRIGHT"
-.IX Header "COPYRIGHT"
-Copyright (c) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
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