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Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below).  A copy of the license is included in the section entitled ``GNU Free Documentation License''.

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU software.  Copies published by the Free Software Foundation raise funds for GNU development.

Installing GCC
**************

The latest version of this document is always available at http://gcc.gnu.org/install/.

This document describes the generic installation procedure for GCC as well as detailing some target specific installation instructions.

GCC includes several components that previously were separate distributions with their own installation instructions.  This document supersedes all package specific installation instructions.

Before starting the build/install procedure please check the host/target specific installation notes. We recommend you browse the entire generic installation instructions before you proceed.

Lists of successful builds for released versions of GCC are available at http://gcc.gnu.org/buildstat.html. These lists are updated as new information becomes available.

The installation procedure itself is broken into five steps.

Please note that GCC does not support make uninstall and probably won't do so in the near future as this would open a can of worms.  Instead, we suggest that you install GCC into a directory of its own and simply remove that directory when you do not need that specific version of GCC any longer, and, if shared libraries are installed there as well, no more binaries exist that use them.

Downloading GCC
***************

GCC is distributed via CVS and FTP tarballs compressed with gzip or bzip2.  It is possible to download a full distribution or specific components.

Please refer to our releases web page for information on how to obtain GCC.

The full distribution includes the C, C++, Objective-C, Fortran, Java, and Ada (in case of GCC 3.1 and later) compilers.  The full distribution also includes runtime libraries for C++, Objective-C, Fortran, and Java. In GCC 3.0 and later versions, GNU compiler testsuites are also included in the full distribution.

If you choose to download specific components, you must download the core GCC distribution plus any language specific distributions you wish to use.  The core distribution includes the C language front end as well as the shared components.  Each language has a tarball which includes the language front end as well as the language runtime (when appropriate).

Unpack the core distribution as well as any language specific distributions in the same directory.

If you also intend to build binutils (either to upgrade an existing installation or for use in place of the corresponding tools of your OS), unpack the binutils distribution either in the same directory or a separate one.  In the latter case, add symbolic links to any components of the binutils you intend to build alongside the compiler (bfd, binutils, gas, gprof, ld, opcodes, ...) to the directory containing the GCC sources.

Installing GCC: Configuration
*****************************

Like most GNU software, GCC must be configured before it can be built. This document describes the recommended configuration procedure for both native and cross targets.

We use SRCDIR to refer to the toplevel source directory for GCC; we use OBJDIR to refer to the toplevel build/object directory.

If you obtained the sources via CVS, SRCDIR must refer to the top gcc directory, the one where the MAINTAINERS can be found, and not its gcc subdirectory, otherwise the build will fail.

If either SRCDIR or OBJDIR is located on an automounted NFS file system, the shell's built-in pwd command will return temporary pathnames.  Using these can lead to various sorts of build problems.  To avoid this issue, set the PWDCMD environment variable to an automounter-aware pwd command, e.g., pawd or amq -w, during the configuration and build phases.

First, we highly recommend that GCC be built into a separate directory than the sources which does not reside within the source tree.  This is how we generally build GCC; building where SRCDIR == OBJDIR should still work, but doesn't get extensive testing; building where OBJDIR is a subdirectory of SRCDIR is unsupported.

If you have previously built GCC in the same directory for a different target machine, do make distclean to delete all files that might be invalid.  One of the files this deletes is Makefile; if make distclean complains that Makefile does not exist or issues a message like ``don't know how to make distclean'' it probably means that the directory is already suitably clean.  However, with the recommended method of building in a separate OBJDIR, you should simply use a different OBJDIR for each target.

Second, when configuring a native system, either cc or gcc must be in your path or you must set CC in your environment before running configure.  Otherwise the configuration scripts may fail.

Note that the bootstrap compiler and the resulting GCC must be link compatible, else the bootstrap will fail with linker errors about incompatible object file formats.  Several multilibed targets are affected by this requirement, see host/target specific installation notes.

To configure GCC:

        % mkdir OBJDIR
        % cd OBJDIR
        % SRCDIR/configure [OPTIONS] [TARGET]

Target specification
====================

  * GCC has code to correctly determine the correct value for TARGET for nearly all native systems.  Therefore, we highly recommend you not provide a configure target when configuring a native compiler.

  * TARGET must be specified as --target=TARGET when configuring a cross compiler; examples of valid targets would be i960-rtems, m68k-coff, sh-elf, etc.

  * Specifying just TARGET instead of --target=TARGET implies that the host defaults to TARGET.

Options specification
=====================

Use OPTIONS to override several configure time options for GCC.  A list of supported OPTIONS follows; configure --help may list other options, but those not listed below may not work and should not normally be used.

--prefix=DIRNAME
     Specify the toplevel installation directory.  This is the recommended way to install the tools into a directory other than the default.  The toplevel installation directory defaults to /usr/local.

     We highly recommend against DIRNAME being the same or a subdirectory of OBJDIR or vice versa.

     These additional options control where certain parts of the distribution are installed.  Normally you should not need to use these options.

     --exec-prefix=DIRNAME
          Specify the toplevel installation directory for architecture-dependent files.  The default is PREFIX.

     --bindir=DIRNAME
          Specify the installation directory for the executables called by users (such as gcc and g++).  The default is EXEC-PREFIX/bin.

     --libdir=DIRNAME
          Specify the installation directory for object code libraries and internal parts of GCC.  The default is EXEC-PREFIX/lib.

     --with-slibdir=DIRNAME
          Specify the installation directory for the shared libgcc library.  The default is LIBDIR.

     --infodir=DIRNAME
          Specify the installation directory for documentation in info format. The default is PREFIX/info.

     --datadir=DIRNAME
          Specify the installation directory for some architecture-independent data files referenced by GCC.  The default is PREFIX/share.

     --mandir=DIRNAME
          Specify the installation directory for manual pages.  The default is PREFIX/man.  (Note that the manual pages are only extracts from the full GCC manuals, which are provided in Texinfo format.  The g77 manpage is unmaintained and may be out of date; the others are derived by an automatic conversion process from parts of the full manual.)

     --with-gxx-include-dir=DIRNAME
          Specify the installation directory for G++ header files.  The default is PREFIX/include/g++-v3.

--program-prefix=PREFIX
     GCC supports some transformations of the names of its programs when installing them. This option prepends PREFIX to the names of programs to install in BINDIR (see above). For example, specifying --program-prefix=foo- would result in gcc being installed as /usr/local/bin/foo-gcc.

--program-suffix=SUFFIX
     Appends SUFFIX to the names of programs to install in BINDIR (see above). For example, specifying --program-suffix=-3.1 would result in gcc being installed as /usr/local/bin/gcc-3.1.

--program-transform-name=PATTERN
     Applies the sed script PATTERN to be applied to the names of programs to install in BINDIR (see above). PATTERN has to consist of one or more basic sed editing commands, separated by semicolons. For example, if you want the gcc program name to be transformed to the installed program /usr/local/bin/myowngcc and the g++ program name to be transformed to /usr/local/bin/gspecial++ without changing other program names, you could use the pattern --program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/' to achieve this effect.

     All three options can be combined and used together, resulting in more complex conversion patterns. As a basic rule, PREFIX (and SUFFIX) are prepended (appended) before further transformations can happen with a special transformation script PATTERN.

     As currently implemented, this option only takes effect for native builds; cross compiler binaries' names are not transformed even when a transformation is explicitly asked for by one of these options.

     For native builds, some of the installed programs are also installed with the target alias in front of their name, as in i686-pc-linux-gnu-gcc. All of the above transformations happen before the target alias is prepended to the name - so, specifying --program-prefix=foo- and program-suffix=-3.1, the resulting binary would be installed as /usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1.

     As a last shortcoming, none of the installed Ada programs are transformed yet, which will be fixed in some time.

--with-local-prefix=DIRNAME
     Specify the installation directory for local include files.  The default is /usr/local.  Specify this option if you want the compiler to search directory DIRNAME/include for locally installed header files instead of /usr/local/include.

     You should specify --with-local-prefix only if your site has a different convention (not /usr/local) for where to put site-specific files.

     The default value for --with-local-prefix is /usr/local regardless of the value of --prefix.  Specifying --prefix has no effect on which directory GCC searches for local header files.  This may seem counterintuitive, but actually it is logical.

     The purpose of --prefix is to specify where to install GCC.  The local header files in /usr/local/include---if you put any in that directory---are not part of GCC.  They are part of other programs---perhaps many others.  (GCC installs its own header files in another directory which is based on the --prefix value.)

     Both the local-prefix include directory and the GCC-prefix include directory are part of GCC's "system include" directories.  Although these two directories are not fixed, they need to be searched in the proper order for the correct processing of the include_next directive.  The local-prefix include directory is searched before the GCC-prefix include directory.  Another characteristic of system include directories is that pedantic warnings are turned off for headers in these directories.

     Some autoconf macros add -I DIRECTORY options to the compiler command line, to ensure that directories containing installed packages' headers are searched.  When DIRECTORY is one of GCC's system include directories, GCC will ignore the option so that system directories continue to be processed in the correct order.  This may result in a search order different from what was specified but the directory will still be searched.

     GCC automatically searches for ordinary libraries using GCC_EXEC_PREFIX.  Thus, when the same installation prefix is used for both GCC and packages, GCC will automatically search for both headers and libraries.  This provides a configuration that is easy to use.  GCC behaves in a manner similar to that when it is installed as a system compiler in /usr.

     Sites that need to install multiple versions of GCC may not want to use the above simple configuration.  It is possible to use the --program-prefix, --program-suffix and --program-transform-name options to install multiple versions into a single directory, but it may be simpler to use different prefixes and the --with-local-prefix option to specify the location of the site-specific files for each version.  It will then be necessary for users to specify explicitly the location of local site libraries (e.g., with LIBRARY_PATH).

     The same value can be used for both --with-local-prefix and --prefix provided it is not /usr.  This can be used to avoid the default search of /usr/local/include.

     Do not specify /usr as the --with-local-prefix! The directory you use for --with-local-prefix must not contain any of the system's standard header files.  If it did contain them, certain programs would be miscompiled (including GNU Emacs, on certain targets), because this would override and nullify the header file corrections made by the fixincludes script.

     Indications are that people who use this option use it based on mistaken ideas of what it is for.  People use it as if it specified where to install part of GCC.  Perhaps they make this assumption because installing GCC creates the directory.

--enable-shared[=PACKAGE[,...]]
     Build shared versions of libraries, if shared libraries are supported on the target platform.  Unlike GCC 2.95.x and earlier, shared libraries are enabled by default on all platforms that support shared libraries, except for libobjc which is built as a static library only by default.

     If a list of packages is given as an argument, build shared libraries only for the listed packages.  For other packages, only static libraries will be built.  Package names currently recognized in the GCC tree are libgcc (also known as gcc), libstdc++ (not libstdc++-v3), libffi, zlib, boehm-gc and libjava.  Note that libobjc does not recognize itself by any name, so, if you list package names in --enable-shared, you will only get static Objective-C libraries.  libf2c and libiberty do not support shared libraries at all.

     Use --disable-shared to build only static libraries.  Note that --disable-shared does not accept a list of package names as argument, only --enable-shared does.

--with-gnu-as
     Specify that the compiler should assume that the assembler it finds is the GNU assembler.  However, this does not modify the rules to find an assembler and will result in confusion if the assembler found is not actually the GNU assembler.  (Confusion may also result if the compiler finds the GNU assembler but has not been configured with --with-gnu-as.)  If you have more than one assembler installed on your system, you may want to use this option in connection with --with-as=PATHNAME.

     The following systems are the only ones where it makes a difference whether you use the GNU assembler.  On any other system, --with-gnu-as has no effect.

       bullet hppa1.0-ANY-ANY

       bullet hppa1.1-ANY-ANY

       bullet i386-ANY-sysv

       bullet i386-ANY-isc

       bullet i860-ANY-bsd

       bullet m68k-bull-sysv

       bullet m68k-hp-hpux

       bullet m68k-sony-bsd

       bullet m68k-altos-sysv

       bullet m68000-hp-hpux

       bullet m68000-att-sysv

       bullet ANY-lynx-lynxos

       bullet mips-ANY

     On the systems listed above (except for the HP-PA, for ISC on the 386, and for mips-sgi-irix5.*), if you use the GNU assembler, you should also use the GNU linker (and specify --with-gnu-ld).

--with-as=PATHNAME
     Specify that the compiler should use the assembler pointed to by PATHNAME, rather than the one found by the standard rules to find an assembler, which are:

       * Check the EXEC_PREFIX/lib/gcc-lib/TARGET/VERSION directory, where EXEC_PREFIX defaults to PREFIX which defaults to /usr/local unless overridden by the --prefix=PATHNAME switch described above. TARGET is the target system triple, such as sparc-sun-solaris2.7, and VERSION denotes the GCC version, such as 3.0.

       * Check operating system specific directories (e.g. /usr/ccs/bin on Sun Solaris 2).

     Note that these rules do not check for the value of PATH.  You may want to use --with-as if no assembler is installed in the directories listed above, or if you have multiple assemblers installed and want to choose one that is not found by the above rules.

--with-gnu-ld
     Same as --with-gnu-as but for linker.

--with-ld=PATHNAME
     Same as --with-as, but for the linker.

--with-stabs
     Specify that stabs debugging information should be used instead of whatever format the host normally uses.  Normally GCC uses the same debug format as the host system.

     On MIPS based systems and on Alphas, you must specify whether you want GCC to create the normal ECOFF debugging format, or to use BSD-style stabs passed through the ECOFF symbol table.  The normal ECOFF debug format cannot fully handle languages other than C.  BSD stabs format can handle other languages, but it only works with the GNU debugger GDB.

     Normally, GCC uses the ECOFF debugging format by default; if you prefer BSD stabs, specify --with-stabs when you configure GCC.

     No matter which default you choose when you configure GCC, the user can use the -gcoff and -gstabs+ options to specify explicitly the debug format for a particular compilation.

     --with-stabs is meaningful on the ISC system on the 386, also, if --with-gas is used.  It selects use of stabs debugging information embedded in COFF output.  This kind of debugging information supports C++ well; ordinary COFF debugging information does not.

     --with-stabs is also meaningful on 386 systems running SVR4.  It selects use of stabs debugging information embedded in ELF output.  The C++ compiler currently (2.6.0) does not support the DWARF debugging information normally used on 386 SVR4 platforms; stabs provide a workable alternative.  This requires gas and gdb, as the normal SVR4 tools can not generate or interpret stabs.

--disable-multilib
     Specify that multiple target libraries to support different target variants, calling conventions, etc should not be built.  The default is to build a predefined set of them.

     Some targets provide finer-grained control over which multilibs are built (e.g., --disable-softfloat):

     arc-*-elf*
          biendian.

     arm-*-*
          fpu, 26bit, underscore, interwork, biendian, nofmult.

     m68*-*-*
          softfloat, m68881, m68000, m68020.

     mips*-*-*
          single-float, biendian, softfloat.

     powerpc*-*-*, rs6000*-*-*
          aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, sysv, aix.

--enable-threads
     Specify that the target supports threads.  This affects the Objective-C compiler and runtime library, and exception handling for other languages like C++ and Java. On some systems, this is the default.

     In general, the best (and, in many cases, the only known) threading model available will be configured for use.  Beware that on some systems, gcc has not been taught what threading models are generally available for the system.  In this case, --enable-threads is an alias for --enable-threads=single.

--disable-threads
     Specify that threading support should be disabled for the system. This is an alias for --enable-threads=single.

--enable-threads=LIB
     Specify that LIB is the thread support library.  This affects the Objective-C compiler and runtime library, and exception handling for other languages like C++ and Java.  The possibilities for LIB are:

     aix
          AIX thread support.

     dce
          DCE thread support.

     mach
          Generic MACH thread support, known to work on NeXTSTEP.  (Please note that the file needed to support this configuration, gthr-mach.h, is missing and thus this setting will cause a known bootstrap failure.)

     no
          This is an alias for single.

     posix
          Generic POSIX thread support.

     pthreads
          Same as posix on arm*-*-linux*, *-*-chorusos* and *-*-freebsd* only.  A future release of gcc might remove this alias or extend it to all platforms.

     rtems
          RTEMS thread support.

     single
          Disable thread support, should work for all platforms.

     solaris
          Sun Solaris 2 thread support.

     vxworks
          VxWorks thread support.

     win32
          Microsoft Win32 API thread support.

--with-cpu=CPU
     Specify which cpu variant the compiler should generate code for by default.  This is currently only supported on some ports, specifically arm, powerpc, and SPARC.  If configure does not recognize the model name (e.g. arm700, 603e, or ultrasparc) you provide, please check the configure script for a complete list of supported models.

--enable-altivec
     Specify that the target supports AltiVec vector enhancements.  This option will adjust the ABI for AltiVec enhancements, as well as generate AltiVec code when appropriate.  This option is only available for PowerPC systems.

--enable-target-optspace
     Specify that target libraries should be optimized for code space instead of code speed. This is the default for the m32r platform.

--disable-cpp
     Specify that a user visible cpp program should not be installed.

--with-cpp-install-dir=DIRNAME
     Specify that the user visible cpp program should be installed in PREFIX/DIRNAME/cpp, in addition to BINDIR.

--enable-initfini-array
     Force the use of sections .init_array and .fini_array (instead of .init and .fini) for constructors and destructors.  Option --disable-initfini-array has the opposite effect.  If neither option is specified, the configure script will try to guess whether the .init_array and .fini_array sections are supported and, if they are, use them.

--enable-maintainer-mode
     The build rules that regenerate the GCC master message catalog gcc.pot are normally disabled.  This is because it can only be rebuilt if the complete source tree is present.  If you have changed the sources and want to rebuild the catalog, configuring with --enable-maintainer-mode will enable this.  Note that you need a recent version of the gettext tools to do so.

--enable-version-specific-runtime-libs
     Specify that runtime libraries should be installed in the compiler specific subdirectory (LIBSUBDIR) rather than the usual places.  In addition, libstdc++'s include files will be installed in LIBSUBDIR/include/g++ unless you overruled it by using --with-gxx-include-dir=DIRNAME.  Using this option is particularly useful if you intend to use several versions of GCC in parallel. This is currently supported by libf2c and libstdc++, and is the default for libobjc which cannot be changed in this case.

--enable-languages=LANG1,LANG2,...
     Specify that only a particular subset of compilers and their runtime libraries should be built.  For a list of valid values for LANGN you can issue the following command in the gcc directory of your GCC source tree:

          grep language= */config-lang.in

     Currently, you can use any of the following: ada, c, c++, f77, java, objc. Building the Ada compiler has special requirements, see below.

     If you do not pass this flag, all languages available in the gcc sub-tree will be configured.  Re-defining LANGUAGES when calling make bootstrap does not work anymore, as those language sub-directories might not have been configured!

--disable-libgcj
     Specify that the run-time libraries used by GCJ should not be built.  This is useful in case you intend to use GCJ with some other run-time, or you're going to install it separately, or it just happens not to build on your particular machine.  In general, if the Java front end is enabled, the GCJ libraries will be enabled too, unless they're known to not work on the target platform.  If GCJ is enabled but libgcj isn't built, you may need to port it; in this case, before modifying the top-level configure.in so that libgcj is enabled by default on this platform, you may use --enable-libgcj to override the default.

--with-dwarf2
     Specify that the compiler should use DWARF 2 debugging information as the default.

--enable-win32-registry
--enable-win32-registry=KEY
--disable-win32-registry
     The --enable-win32-registry option enables Windows-hosted GCC to look up installations paths in the registry using the following key:

          HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\KEY

     KEY defaults to GCC version number, and can be overridden by the --enable-win32-registry=KEY option. Vendors and distributors who use custom installers are encouraged to provide a different key, perhaps one comprised of vendor name and GCC version number, to avoid conflict with existing installations.  This feature is enabled by default, and can be disabled by --disable-win32-registry option.  This option has no effect on the other hosts.

--nfp
     Specify that the machine does not have a floating point unit.  This option only applies to m68k-sun-sunosN and m68k-isi-bsd.  On any other system, --nfp has no effect.

--enable-checking
--enable-checking=LIST
     When you specify this option, the compiler is built to perform checking of tree node types when referencing fields of that node, and some other internal consistency checks.  This does not change the generated code, but adds error checking within the compiler.  This will slow down the compiler and may only work properly if you are building the compiler with GCC.  This is on by default when building from CVS or snapshots, but off for releases.  More control over the checks may be had by specifying LIST; the categories of checks available are misc, tree, gc, rtl, rtlflag and gcac.  The default when LIST is not specified is misc,tree,gc,rtlflag; the checks rtl and gcac are very expensive.

--enable-coverage

--enable-coverage=LEVEL
     With this option, the compiler is built to collect self coverage information, every time it is run. This is for internal development purposes, and only works when the compiler is being built with gcc. The LEVEL argument controls whether the compiler is built optimized or not, values are opt and noopt. For coverage analysis you want to disable optimization, for performance analysis you want to enable optimization. When coverage is enabled, the default level is without optimization.

--enable-nls
--disable-nls
     The --enable-nls option enables Native Language Support (NLS), which lets GCC output diagnostics in languages other than American English.  Native Language Support is enabled by default if not doing a canadian cross build.  The --disable-nls option disables NLS.

--with-included-gettext
     If NLS is enabled, the --with-included-gettext option causes the build procedure to prefer its copy of GNU gettext.

--with-catgets
     If NLS is enabled, and if the host lacks gettext but has the inferior catgets interface, the GCC build procedure normally ignores catgets and instead uses GCC's copy of the GNU gettext library.  The --with-catgets option causes the build procedure to use the host's catgets in this situation.

--with-libiconv-prefix=DIR
     Search for libiconv header files in DIR/include and libiconv library files in DIR/lib.

--with-system-zlib
     Use installed zlib rather than that included with GCC.  This option only applies if the Java front end is being built.

--enable-obsolete
     Enable configuration for an obsoleted system.  If you attempt to configure GCC for a system (build, host, or target) which has been obsoleted, and you do not specify this flag, configure will halt with an error message.

     All support for systems which have been obsoleted in one release of GCC is removed entirely in the next major release, unless someone steps forward to maintain the port.

Some options which only apply to building cross compilers:

--with-sysroot
--with-sysroot=DIR
     Tells GCC to consider DIR as the root of a tree that contains a (subset of) the root filesystem of the target operating system. Target system headers, libraries and run-time object files will be searched in there.  The specified directory is not copied into the install tree, unlike the options --with-headers and --with-libs that this option obsoletes.  The default value, in case --with-sysroot is not given an argument, is ${gcc_tooldir}/sys-root.  Starting the pathname with ${gcc_tooldir}/, in such a way that this variable is not expanded by the shell, but rather by the gcc Makefile, enables the target sysroot directory to be relocatable along with the entire install tree, but it will require the gcc tool directory to be created before the build is started.  This directory, as well as its intermediate pathnames, can be easily created by running make install-gcc-tooldir the gcc build directory.  This is not done automatically to avoid touching the install tree without explicit permission.

--with-headers
--with-headers=DIR
     Deprecated in favor of --with-sysroot. Specifies that target headers are available when building a cross compiler. The DIR argument specifies a directory which has the target include files.  These include files will be copied into the gcc install directory.  This option with the DIR argument is required when building a cross compiler, if PREFIX/TARGET/sys-include doesn't pre-exist.  If PREFIX/TARGET/sys-include does pre-exist, the DIR argument may be omitted.  fixincludes will be run on these files to make them compatible with GCC.

--with-libs
--with-libs=``DIR1 DIR2 ... DIRN''
     Deprecated in favor of --with-sysroot. Specifies a list of directories which contain the target runtime libraries.  These libraries will be copied into the gcc install directory.  If the directory list is omitted, this option has no effect.

--with-newlib
     Specifies that newlib is being used as the target C library.  This causes __eprintf to be omitted from libgcc.a on the assumption that it will be provided by newlib.

Note that each --enable option has a corresponding --disable option and that each --with option has a corresponding --without option.

Building
********

Now that GCC is configured, you are ready to build the compiler and runtime libraries.

We highly recommend that GCC be built using GNU make; other versions may work, then again they might not. GNU make is required for compiling GNAT (the Ada compiler) and the Java runtime library.

(For example, many broken versions of make will fail if you use the recommended setup where OBJDIR is different from SRCDIR. Other broken versions may recompile parts of the compiler when installing the compiler.)

Some commands executed when making the compiler may fail (return a nonzero status) and be ignored by make.  These failures, which are often due to files that were not found, are expected, and can safely be ignored.

It is normal to have compiler warnings when compiling certain files. Unless you are a GCC developer, you can generally ignore these warnings unless they cause compilation to fail.

On certain old systems, defining certain environment variables such as CC can interfere with the functioning of make.

If you encounter seemingly strange errors when trying to build the compiler in a directory other than the source directory, it could be because you have previously configured the compiler in the source directory.  Make sure you have done all the necessary preparations.

If you build GCC on a BSD system using a directory stored in an old System V file system, problems may occur in running fixincludes if the System V file system doesn't support symbolic links.  These problems result in a failure to fix the declaration of size_t in sys/types.h.  If you find that size_t is a signed type and that type mismatches occur, this could be the cause.

The solution is not to use such a directory for building GCC.

When building from CVS or snapshots, or if you modify parser sources, you need the Bison parser generator installed.  Any version 1.25 or later should work; older versions may also work.  If you do not modify parser sources, releases contain the Bison-generated files and you do not need Bison installed to build them.

When building from CVS or snapshots, or if you modify Texinfo documentation, you need version 4.1 or later of Texinfo installed if you want Info documentation to be regenerated.  Releases contain Info documentation pre-built for the unmodified documentation in the release.

Building a native compiler
==========================

For a native build issue the command make bootstrap.  This will build the entire GCC system, which includes the following steps:

  * Build host tools necessary to build the compiler such as texinfo, bison, gperf.

  * Build target tools for use by the compiler such as binutils (bfd, binutils, gas, gprof, ld, and opcodes) if they have been individually linked or moved into the top level GCC source tree before configuring.

  * Perform a 3-stage bootstrap of the compiler.

  * Perform a comparison test of the stage2 and stage3 compilers.

  * Build runtime libraries using the stage3 compiler from the previous step.

If you are short on disk space you might consider make bootstrap-lean instead.  This is identical to make bootstrap except that object files from the stage1 and stage2 of the 3-stage bootstrap of the compiler are deleted as soon as they are no longer needed.

If you want to save additional space during the bootstrap and in the final installation as well, you can build the compiler binaries without debugging information as in the following example.  This will save roughly 40% of disk space both for the bootstrap and the final installation. (Libraries will still contain debugging information.)

          make CFLAGS='-O' LIBCFLAGS='-g -O2' \
            LIBCXXFLAGS='-g -O2 -fno-implicit-templates' bootstrap

If you wish to use non-default GCC flags when compiling the stage2 and stage3 compilers, set BOOT_CFLAGS on the command line when doing make bootstrap.  Non-default optimization flags are less well tested here than the default of -g -O2, but should still work. In a few cases, you may find that you need to specify special flags such as -msoft-float here to complete the bootstrap; or, if the native compiler miscompiles the stage1 compiler, you may need to work around this, by choosing BOOT_CFLAGS to avoid the parts of the stage1 compiler that were miscompiled, or by using make bootstrap4 to increase the number of stages of bootstrap.

If you used the flag --enable-languages=... to restrict the compilers to be built, only those you've actually enabled will be built.  This will of course only build those runtime libraries, for which the particular compiler has been built.  Please note, that re-defining LANGUAGES when calling make bootstrap does not work anymore!

If the comparison of stage2 and stage3 fails, this normally indicates that the stage2 compiler has compiled GCC incorrectly, and is therefore a potentially serious bug which you should investigate and report.  (On a few systems, meaningful comparison of object files is impossible; they always appear ``different''.  If you encounter this problem, you will need to disable comparison in the Makefile.)

Building a cross compiler
=========================

We recommend reading the crossgcc FAQ for information about building cross compilers.

When building a cross compiler, it is not generally possible to do a 3-stage bootstrap of the compiler.  This makes for an interesting problem as parts of GCC can only be built with GCC.

To build a cross compiler, we first recommend building and installing a native compiler.  You can then use the native GCC compiler to build the cross compiler.  The installed native compiler needs to be GCC version 2.95 or later.

Assuming you have already installed a native copy of GCC and configured your cross compiler, issue the command make, which performs the following steps:

  * Build host tools necessary to build the compiler such as texinfo, bison, gperf.

  * Build target tools for use by the compiler such as binutils (bfd, binutils, gas, gprof, ld, and opcodes) if they have been individually linked or moved into the top level GCC source tree before configuring.

  * Build the compiler (single stage only).

  * Build runtime libraries using the compiler from the previous step.

Note that if an error occurs in any step the make process will exit.

Building in parallel
====================

If you have a multiprocessor system you can use make bootstrap MAKE="make -j 2" -j 2 or just make -j 2 bootstrap for GNU Make 3.79 and above instead of just make bootstrap when building GCC.  You can use a bigger number instead of two if you like.  In most cases, it won't help to use a number bigger than the number of processors in your machine.

Building the Ada compiler
=========================

In order to build GNAT, the Ada compiler, you need a working GNAT compiler (GNAT version 3.13 or later, or GCC version 3.1 or later), since the Ada front end is written in Ada (with some GNAT-specific extensions), and GNU make.

However, you do not need a full installation of GNAT, just the GNAT binary gnat1, a copy of gnatbind, and a compiler driver which can deal with Ada input (by invoking the gnat1 binary). You can specify this compiler driver by setting the ADAC environment variable at the configure step.  configure can detect the driver automatically if it has got a common name such as gcc or gnatgcc.  Of course, you still need a working C compiler (the compiler driver can be different or not). configure does not test whether the GNAT installation works and has a sufficiently recent version; if too old a GNAT version is installed, the build will fail unless --enable-languages is used to disable building the Ada front end.

Additional build tools (such as gnatmake) or a working GNAT run-time library installation are usually not required.  However, if you want to bootstrap the compiler using a minimal version of GNAT, you have to issue the following commands before invoking make bootstrap (this assumes that you start with an unmodified and consistent source distribution):

         cd SRCDIR/gcc/ada
         touch treeprs.ads [es]info.h nmake.ad[bs]

At the moment, the GNAT library and several tools for GNAT are not built by make bootstrap.  You have to invoke make gnatlib_and_tools in the OBJDIR/gcc subdirectory before proceeding with the next steps.

For example, you can build a native Ada compiler by issuing the following commands (assuming make is GNU make):

         cd OBJDIR
         SRCDIR/configure --enable-languages=c,ada
         cd SRCDIR/gcc/ada
         touch treeprs.ads [es]info.h nmake.ad[bs]
         cd OBJDIR
         make bootstrap
         cd gcc
         make gnatlib_and_tools
         cd ..

Currently, when compiling the Ada front end, you cannot use the parallel build feature described in the previous section.

Installing GCC: Testing
***********************

Before you install GCC, we encourage you to run the testsuites and to compare your results with results from a similar configuration that have been submitted to the gcc-testresults mailing list. This step is optional and may require you to download additional software, but it can give you confidence in your new GCC installation or point out problems before you install and start using your new GCC.

First, you must have downloaded the testsuites. These are part of the full distribution, but if you downloaded the ``core'' compiler plus any front ends, you must download the testsuites separately.

Second, you must have the testing tools installed.  This includes a current version of DejaGnu; dejagnu 1.3 is not sufficient. It also includes Tcl and Expect; the DejaGnu site has links to these.

Now you may need specific preparations:

  * The following environment variables may need to be set appropriately, as in the following example (which assumes that DejaGnu has been installed under /usr/local):

               TCL_LIBRARY = /usr/local/share/tcl8.0
               DEJAGNULIBS = /usr/local/share/dejagnu

     On systems such as Cygwin, these paths are required to be actual paths, not mounts or links; presumably this is due to some lack of portability in the DejaGnu code.

     If the directories where runtest and expect were installed are in the PATH, it should not be necessary to set these environment variables.

Finally, you can run the testsuite (which may take a long time):

          cd OBJDIR; make -k check

The testing process will try to test as many components in the GCC distribution as possible, including the C, C++, Objective-C and Fortran compilers as well as the C++ and Java runtime libraries.

While running the testsuite, DejaGnu might emit messages resembling WARNING: Couldn't find the global config file. or WARNING: Couldn't find tool init file. These messages are harmless and do not affect the validity of the tests.

How can I run the test suite on selected tests?
===============================================

As a first possibility to cut down the number of tests that are run it is possible to use make check-gcc or make check-g++ in the gcc subdirectory of the object directory.  To further cut down the tests the following is possible:

         make check-gcc RUNTESTFLAGS="execute.exp OTHER-OPTIONS"

This will run all gcc execute tests in the testsuite.

         make check-g++ RUNTESTFLAGS="old-deja.exp=9805* OTHER-OPTIONS"

This will run the g++ ``old-deja'' tests in the testsuite where the filename matches 9805*.

The *.exp files are located in the testsuite directories of the GCC source, the most important ones being compile.exp, execute.exp, dg.exp and old-deja.exp. To get a list of the possible *.exp files, pipe the output of make check into a file and look at the Running ...  .exp lines.

To run only the tests for a library, run make check from the the library's testsuite in a subdirectory of the object directory: libstdc++-v3/testsuite or libcgj/testsuite.

Additional testing for Java Class Libraries
===========================================

The Mauve Project provides a suite of tests for the Java Class Libraries.  This suite can be run as part of libgcj testing by placing the Mauve tree within the libjava testsuite at libjava/testsuite/libjava.mauve/mauve, or by specifying the location of that tree when invoking make, as in make MAUVEDIR=~/mauve check.

How to interpret test results
=============================

After the testsuite has run you'll find various *.sum and *.log files in the testsuite subdirectories.  The *.log files contain a detailed log of the compiler invocations and the corresponding results, the *.sum files summarize the results.  These summaries list all the tests that have been run with a corresponding status code:

  * PASS: the test passed as expected

  * XPASS: the test unexpectedly passed

  * FAIL: the test unexpectedly failed

  * XFAIL: the test failed as expected

  * UNSUPPORTED: the test is not supported on this platform

  * ERROR: the testsuite detected an error

  * WARNING: the testsuite detected a possible problem

It is normal for some tests to report unexpected failures.  At the current time our testing harness does not allow fine grained control over whether or not a test is expected to fail.  We expect to fix this problem in future releases.

Submitting test results
=======================

If you want to report the results to the GCC project, use the contrib/test_summary shell script.  Start it in the OBJDIR with

         SRCDIR/contrib/test_summary -p your_commentary.txt \
             -m gcc-testresults@gcc.gnu.org |sh

This script uses the Mail program to send the results, so make sure it is in your PATH.  The file your_commentary.txt is prepended to the testsuite summary and should contain any special remarks you have on your results or your build environment.  Please do not edit the testsuite result block or the subject line, as these messages are automatically parsed and presented at the GCC testresults web page.  Here you can also gather information on how specific tests behave on different platforms and compare them with your results.  A few failing testcases are possible even on released versions and you should look here first if you think your results are unreasonable.

Installing GCC: Final installation
**********************************

Now that GCC has been built (and optionally tested), you can install it with

     cd OBJDIR; make install

We strongly recommend to install into a target directory where there is no previous version of GCC present.

That step completes the installation of GCC; user level binaries can be found in PREFIX/bin where PREFIX is the value you specified with the --prefix to configure (or /usr/local by default).  (If you specified --bindir, that directory will be used instead; otherwise, if you specified --exec-prefix, EXEC-PREFIX/bin will be used.)  Headers for the C++ and Java libraries are installed in PREFIX/include; libraries in LIBDIR (normally PREFIX/lib); internal parts of the compiler in LIBDIR/gcc-lib; documentation in info format in INFODIR (normally PREFIX/info).

If you built a released version of GCC using make bootstrap then please quickly review the build status page for your release, available from http://gcc.gnu.org/buildstat.html. If your system is not listed for the version of GCC that you built, send a note to gcc@gcc.gnu.org indicating that you successfully built and installed GCC. Include the following information:

  * Output from running SRCDIR/config.guess.  Do not send us that file itself, just the one-line output from running it.

  * The output of gcc -v for your newly installed gcc. This tells us which version of GCC you built and the options you passed to configure.

  * Whether you enabled all languages or a subset of them.  If you used a full distribution then this information is part of the configure options in the output of gcc -v, but if you downloaded the ``core'' compiler plus additional front ends then it isn't apparent which ones you built unless you tell us about it.

  * If the build was for GNU/Linux, also include:

       * The distribution name and version (e.g., Red Hat 7.1 or Debian 2.2.3); this information should be available from /etc/issue.

       * The version of the Linux kernel, available from uname --version or uname -a.

       * The version of glibc you used; for RPM-based systems like Red Hat, Mandrake, and SuSE type rpm -q glibc to get the glibc version, and on systems like Debian and Progeny use dpkg -l libc6.

     For other systems, you can include similar information if you think it is relevant.

  * Any other information that you think would be useful to people building GCC on the same configuration.  The new entry in the build status list will include a link to the archived copy of your message.

We'd also like to know if the host/target specific installation notes didn't include your host/target information or if that information is incomplete or out of date.  Send a note to gcc@gcc.gnu.org telling us how the information should be changed.

If you find a bug, please report it following our bug reporting guidelines.

If you want to print the GCC manuals, do cd OBJDIR; make dvi.  You will need to have texi2dvi (version at least 4.1) and TeX installed.  This creates a number of .dvi files in subdirectories of OBJDIR; these may be converted for printing with programs such as dvips.  You can also buy printed manuals from the Free Software Foundation, though such manuals may not be for the most recent version of GCC.

Installing GCC: Binaries
************************

We are often asked about pre-compiled versions of GCC.  While we cannot provide these for all platforms, below you'll find links to binaries for various platforms where creating them by yourself is not easy due to various reasons.

Please note that we did not create these binaries, nor do we support them.  If you have any problems installing them, please contact their makers.

  * AIX:

       * Bull's Freeware and Shareware Archive for AIX;

       * UCLA Software Library for AIX.

  * DOS---DJGPP.

  * Hitachi H8/300[HS]---GNU Development Tools for the Hitachi H8/300[HS] Series.

  * HP-UX:

       * HP-UX Porting Center;

       * Binaries for HP-UX 11.00 at Aachen University of Technology.

  * SCO OpenServer/Unixware.

  * Sinix/Reliant Unix---Siemens.

  * Solaris 2 (SPARC, Intel)---Sunfreeware.

  * SGI---SGI Freeware.

  * Windows 95, 98, and NT:

       * The Cygwin project;

       * The MinGW project.

  * The Written Word offers binaries for Solaris 2.5.1, 2.6, 2.7/SPARC, 2.7/Intel, IRIX 6.2, 6.5, Digital UNIX 4.0D, HP-UX 10.20, and HP-UX 11.00.

In addition to those specific offerings, you can get a binary distribution CD-ROM from the Free Software Foundation. It contains binaries for a number of platforms, and includes not only GCC, but other stuff as well.  The current CD does not contain the latest version of GCC, but it should allow bootstrapping the compiler.  An updated version of that disk is in the works.

Host/target specific installation notes for GCC
***********************************************

Please read this document carefully before installing the GNU Compiler Collection on your machine.

alpha*-*-*
==========

This section contains general configuration information for all alpha-based platforms using ELF (in particular, ignore this section for DEC OSF/1, Digital UNIX and Tru64 UNIX).  In addition to reading this section, please read all other sections that match your target.

We require binutils 2.11.2 or newer. Previous binutils releases had a number of problems with DWARF 2 debugging information, not the least of which is incorrect linking of shared libraries.

alpha*-dec-osf*
===============

Systems using processors that implement the DEC Alpha architecture and are running the DEC/Compaq Unix (DEC OSF/1, Digital UNIX, or Compaq Tru64 UNIX) operating system, for example the DEC Alpha AXP systems.

As of GCC 3.2, versions before alpha*-dec-osf4 are no longer supported.  (These are the versions which identify themselves as DEC OSF/1.)

In Digital Unix V4.0, virtual memory exhausted bootstrap failures may be fixed by configuring with --with-gc=simple, reconfiguring Kernel Virtual Memory and Swap parameters per the /usr/sbin/sys_check Tuning Suggestions, or applying the patch in http://gcc.gnu.org/ml/gcc/2002-08/msg00822.html.

In Tru64 UNIX V5.1, Compaq introduced a new assembler that does not currently (2001-06-13) work with mips-tfile.  As a workaround, we need to use the old assembler, invoked via the barely documented -oldas option.  To bootstrap GCC, you either need to use the Compaq C Compiler:

        % CC=cc SRCDIR/configure [OPTIONS] [TARGET]

or you can use a copy of GCC 2.95.3 or higher built on Tru64 UNIX V4.0:

        % CC=gcc -Wa,-oldas SRCDIR/configure [OPTIONS] [TARGET]

As of GNU binutils 2.11.2, neither GNU as nor GNU ld are supported on Tru64 UNIX, so you must not configure GCC with --with-gnu-as or --with-gnu-ld.

The --enable-threads options isn't supported yet.  A patch is in preparation for a future release.

GCC writes a .verstamp directive to the assembler output file unless it is built as a cross-compiler.  It gets the version to use from the system header file /usr/include/stamp.h.  If you install a new version of DEC Unix, you should rebuild GCC to pick up the new version stamp.

Note that since the Alpha is a 64-bit architecture, cross-compilers from 32-bit machines will not generate code as efficient as that generated when the compiler is running on a 64-bit machine because many optimizations that depend on being able to represent a word on the target in an integral value on the host cannot be performed.  Building cross-compilers on the Alpha for 32-bit machines has only been tested in a few cases and may not work properly.

make compare may fail on old versions of DEC Unix unless you add -save-temps to CFLAGS.  On these systems, the name of the assembler input file is stored in the object file, and that makes comparison fail if it differs between the stage1 and stage2 compilations.  The option -save-temps forces a fixed name to be used for the assembler input file, instead of a randomly chosen name in /tmp.  Do not add -save-temps unless the comparisons fail without that option.  If you add -save-temps, you will have to manually delete the .i and .s files after each series of compilations.

GCC now supports both the native (ECOFF) debugging format used by DBX and GDB and an encapsulated STABS format for use only with GDB.  See the discussion of the --with-stabs option of configure above for more information on these formats and how to select them.

There is a bug in DEC's assembler that produces incorrect line numbers for ECOFF format when the .align directive is used.  To work around this problem, GCC will not emit such alignment directives while writing ECOFF format debugging information even if optimization is being performed.  Unfortunately, this has the very undesirable side-effect that code addresses when -O is specified are different depending on whether or not -g is also specified.

To avoid this behavior, specify -gstabs+ and use GDB instead of DBX.  DEC is now aware of this problem with the assembler and hopes to provide a fix shortly.

alphaev5-cray-unicosmk*
=======================

Cray T3E systems running Unicos/Mk.

This port is incomplete and has many known bugs.  We hope to improve the support for this target soon.  Currently, only the C front end is supported, and it is not possible to build parallel applications.  Cray modules are not supported; in particular, Craylibs are assumed to be in /opt/ctl/craylibs/craylibs.

You absolutely must use GNU make on this platform.  Also, you need to tell GCC where to find the assembler and the linker.  The simplest way to do so is by providing --with-as and --with-ld to configure, e.g.

         configure --with-as=/opt/ctl/bin/cam --with-ld=/opt/ctl/bin/cld \
           --enable-languages=c

The comparison test during make bootstrap fails on Unicos/Mk because the assembler inserts timestamps into object files.  You should be able to work around this by doing make all after getting this failure.

arc-*-elf
=========

Argonaut ARC processor. This configuration is intended for embedded systems.

arm-*-aout
==========

Advanced RISC Machines ARM-family processors.  These are often used in embedded applications.  There are no standard Unix configurations. This configuration corresponds to the basic instruction sequences and will produce a.out format object modules.

You may need to make a variant of the file arm.h for your particular configuration.

arm-*-elf
=========

This configuration is intended for embedded systems.

arm*-*-linux-gnu
================

We require GNU binutils 2.10 or newer.

avr
===

ATMEL AVR-family micro controllers.  These are used in embedded applications.  There are no standard Unix configurations. See AVR Options (Using and Porting the GNU Compiler Collection (GCC)), for the list of supported MCU types.

Use configure --target=avr --enable-languages="c" to configure GCC.

Further installation notes and other useful information about AVR tools can also be obtained from:

  * http://www.openavr.org

  * http://home.overta.ru/users/denisc

  * http://www.amelek.gda.pl/avr

We strongly recommend using binutils 2.13 or newer.

The following error:

       Error: register required

indicates that you should upgrade to a newer version of the binutils.

c4x
===

Texas Instruments TMS320C3x and TMS320C4x Floating Point Digital Signal Processors.  These are used in embedded applications.  There are no standard Unix configurations. See TMS320C3x/C4x Options (Using and Porting the GNU Compiler Collection (GCC)), for the list of supported MCU types.

GCC can be configured as a cross compiler for both the C3x and C4x architectures on the same system.  Use configure --target=c4x --enable-languages="c,c++" to configure.

Further installation notes and other useful information about C4x tools can also be obtained from:

  * http://www.elec.canterbury.ac.nz/c4x/

CRIS
====

CRIS is the CPU architecture in Axis Communications ETRAX system-on-a-chip series.  These are used in embedded applications.

See CRIS Options (Using and Porting the GNU Compiler Collection (GCC)), for a list of CRIS-specific options.

There are a few different CRIS targets:

cris-axis-aout
     Old target.  Includes a multilib for the elinux a.out-based target.  No multilibs for newer architecture variants.

cris-axis-elf
     Mainly for monolithic embedded systems.  Includes a multilib for the v10 core used in ETRAX 100 LX.

cris-axis-linux-gnu
     A GNU/Linux port for the CRIS architecture, currently targeting ETRAX 100 LX by default.

For cris-axis-aout and cris-axis-elf you need binutils 2.11 or newer.  For cris-axis-linux-gnu you need binutils 2.12 or newer.

Pre-packaged tools can be obtained from ftp://ftp.axis.com/pub/axis/tools/cris/compiler-kit/.  More information about this platform is available at http://developer.axis.com/.

DOS
===

Please have a look at our binaries page.

You cannot install GCC by itself on MSDOS; it will not compile under any MSDOS compiler except itself.  You need to get the complete compilation package DJGPP, which includes binaries as well as sources, and includes all the necessary compilation tools and libraries.

dsp16xx
=======

A port to the AT&T DSP1610 family of processors.

*-*-freebsd*
============

The version of binutils installed in /usr/bin is known to work unless otherwise specified in any per-architecture notes.  However, binutils 2.12.1 or greater is known to improve overall testsuite results.

FreeBSD 1 is no longer supported in GCC 3.2.

For FreeBSD 2 or any mutant a.out versions of FreeBSD 3: All configuration support and files as shipped with GCC 2.95 are still in place.  FreeBSD 2.2.7 has been known to bootstrap completely; however, it is unknown which version of binutils was used (it is assumed that it was the system copy in /usr/bin) and C++ EH failures were noted.

For FreeBSD using the ELF file format: DWARF 2 debugging is now the default for all CPU architectures.  It had been the default on FreeBSD/alpha since its inception.  You may use -gstabs instead of -g, if you really want the old debugging format.  There are no known issues with mixing object files and libraries with different debugging formats.  Otherwise, this release of GCC should now match more of the configuration used in the stock FreeBSD configuration of GCC.  In particular, --enable-threads is now configured by default. However, as a general user, do not attempt to replace the system compiler with this release.  Known to bootstrap and check with good results on FreeBSD 3.0, 3.4, 4.0, 4.2, 4.3, 4.4, 4.5-STABLE and 5-CURRENT.

In principle, --enable-threads is now compatible with --enable-libgcj on FreeBSD.  However, it has only been built and tested on i386-*-freebsd4.5 and alpha-*-freebsd5.0. The static library may be incorrectly built (symbols are missing at link time). There is a rare timing-based startup hang (probably involves an assumption about the thread library).  Multi-threaded boehm-gc (required for libjava) exposes severe threaded signal-handling bugs on FreeBSD before 4.5-RELEASE.  The alpha port may not fully bootstrap without some manual intervention: gcjh will crash with a floating-point exception while generating java/lang/Double.h (just copy the version built on i386-*-freebsd* and rerun the top-level gmake with no arguments and it should properly complete the bootstrap).  Other CPU architectures supported by FreeBSD will require additional configuration tuning in, at the very least, both boehm-gc and libffi.

Shared libgcc_s.so is now built and installed by default.

h8300-hms
=========

Hitachi H8/300 series of processors.

Please have a look at our binaries page.

The calling convention and structure layout has changed in release 2.6. All code must be recompiled.  The calling convention now passes the first three arguments in function calls in registers.  Structures are no longer a multiple of 2 bytes.

hppa*-hp-hpux*
==============

We highly recommend using gas/binutils 2.8 or newer on all hppa platforms; you may encounter a variety of problems when using the HP assembler.

Specifically, -g does not work on HP-UX (since that system uses a peculiar debugging format which GCC does not know about), unless you use GAS and GDB and configure GCC with the --with-gnu-as and --with-as=... options.

If you wish to use the pa-risc 2.0 architecture support with a 32-bit runtime, you must use either the HP assembler, gas/binutils 2.11 or newer, or a recent snapshot of gas.

There are two default scheduling models for instructions.  These are PROCESSOR_7100LC and PROCESSOR_8000.  They are selected from the pa-risc architecture specified for the target machine when configuring. PROCESSOR_8000 is the default.  PROCESSOR_7100LC is selected when the target is a hppa1* machine.

The PROCESSOR_8000 model is not well suited to older processors.  Thus, it is important to completely specify the machine architecture when configuring if you want a model other than PROCESSOR_8000.  The macro TARGET_SCHED_DEFAULT can be defined in BOOT_CFLAGS if a different default scheduling model is desired.

More specific information to hppa*-hp-hpux* targets follows.

hppa*-hp-hpux9
==============

The HP assembler has major problems on this platform.  We've tried to work around the worst of the problems.  However, those workarounds may be causing linker crashes in some circumstances; the workarounds also probably prevent shared libraries from working.  Use the GNU assembler to avoid these problems.

The configuration scripts for GCC will also trigger a bug in the hpux9 shell.  To avoid this problem set CONFIG_SHELL to /bin/ksh and SHELL to /bin/ksh in your environment.

hppa*-hp-hpux10
===============

For hpux10.20, we highly recommend you pick up the latest sed patch PHCO_19798 from HP.  HP has two sites which provide patches free of charge:

  * http://us-support.external.hp.comUS, Canada, Asia-Pacific, and Latin-America

  * Europe

The HP assembler on these systems is much better than the hpux9 assembler, but still has some problems.  Most notably the assembler inserts timestamps into each object file it creates, causing the 3-stage comparison test to fail during a make bootstrap.  You should be able to continue by saying make all after getting the failure from make bootstrap.

hppa*-hp-hpux11
===============

GCC 3.0 and up support HP-UX 11.  On 64-bit capable systems, there are two distinct ports.  The hppa2.0w-hp-hpux11* port generates code for the 32-bit pa-risc runtime architecture.  It uses the HP linker and is currently the default selected by config.guess.  The optional hppa64-hp-hpux11* port generates 64-bit code for the pa-risc 2.0 architecture.  It must be explicitly selected using the --host=hppa64-hp-hpux11* configure option.  Different prefixes must be used if both ports are to be installed on the same system.

You must use GNU binutils 2.11 or above with the 32-bit port.  Thread support is not currently implemented, so --enable-threads does not work.  See:

  * http://gcc.gnu.org/ml/gcc-prs/2002-01/msg00551.html

  * http://gcc.gnu.org/ml/gcc-bugs/2002-01/msg00663.html

GCC 2.95.x is not supported under HP-UX 11 and cannot be used to compile GCC 3.0 and up.  Refer to binaries for information about obtaining precompiled GCC binaries for HP-UX.

GNU binutils 2.13 or later is recommended with the 64-bit port. The HP assembler has many limitations and is not recommended.  For example, it does not support weak symbols or alias definitions. As a result, explicit template instantiations are required when using C++.  Either the HP or GNU linker can be used but it may be necessary to use the GNU linker when dwarf2 exception support is implemented.

There are several possible approaches to building the distribution. Binutils can be built first using the HP tools.  Then, the GCC distribution can be built.  The second approach is to build GCC first using the HP tools, then build binutils, then rebuild GCC. There have been problems with various binary distributions, so it is best not to start from a binary distribution.

When starting with a HP compiler, it is preferable to use the ANSI compiler as the bundled compiler only supports traditional C. Bootstrapping with the bundled compiler is tested infrequently and problems often arise because of the subtle differences in semantics between traditional and ISO C.

This port still is undergoing significant development.

i370-*-*
========

This port is very preliminary and has many known bugs.  We hope to have a higher-quality port for this machine soon.

*-*-linux-gnu
=============

If you use glibc 2.2 (or 2.1.9x), GCC 2.95.2 won't install out-of-the-box.  You'll get compile errors while building libstdc++. The patch glibc-2.2.patch, that is to be applied in the GCC source tree, fixes the compatibility problems.

Currently Glibc 2.2.3 (and older releases) and GCC 3.0 are out of sync since the latest exception handling changes for GCC.  Compiling glibc with GCC 3.0 will give a binary incompatible glibc and therefore cause lots of problems and might make your system completly unusable.  This will definitly need fixes in glibc but might also need fixes in GCC.  We strongly advise to wait for glibc 2.2.4 and to read the release notes of glibc 2.2.4 whether patches for GCC 3.0 are needed.  You can use glibc 2.2.3 with GCC 3.0, just do not try to recompile it.

i?86-*-linux*aout
=================

Use this configuration to generate a.out binaries on Linux-based GNU systems.  This configuration is being superseded.  You must use gas/binutils version 2.5.2 or later.

i?86-*-linux*
=============

You will need binutils 2.9.1.0.15 or newer for exception handling to work.

If you receive Signal 11 errors when building on GNU/Linux, then it is possible you have a hardware problem.  Further information on this can be found on www.bitwizard.nl.

i?86-*-sco
==========

Compilation with RCC is recommended.  Also, it may be a good idea to link with GNU malloc instead of the malloc that comes with the system.

i?86-*-sco3.2v4
===============

Use this configuration for SCO release 3.2 version 4.

i?86-*-sco3.2v5*
================

Use this for the SCO OpenServer Release 5 family of operating systems.

Unlike earlier versions of GCC, the ability to generate COFF with this target is no longer provided.

Earlier versions of GCC emitted DWARF 1 when generating ELF to allow the system debugger to be used.  That support was too burdensome to maintain.  GCC now emits only DWARF 2 for this target.  This means you may use either the UDK debugger or GDB to debug programs built by this version of GCC.

Use of the -march=pentiumpro flag can result in unrecognized opcodes when using the native assembler on OS versions before 5.0.6.  (Support for P6 opcodes was added to the native ELF assembler in that version.)  While it's rather rare to see these emitted by GCC yet, errors of the basic form:

       /usr/tmp/ccaNlqBc.s:22:unknown instruction: fcomip
       /usr/tmp/ccaNlqBc.s:50:unknown instruction: fucomip

are symptoms of this problem.  You may work around this by not building affected files with that flag, by using the GNU assembler, or by using the assembler provided with the current version of the OS. Users of GNU assembler should see the note below for hazards on doing so.

The native SCO assembler that is provided with the OS at no charge is normally required.  If, however, you must be able to use the GNU assembler (perhaps you're compiling code with asms that require GAS syntax) you may configure this package using the flags --with-gnu-as.  You must use a recent version of GNU binutils; versions past 2.9.1 seem to work well.

In general, the --with-gnu-as option isn't as well tested as the native assembler.

Look in gcc/config/i386/sco5.h (search for ``messy'') for additional OpenServer-specific flags.

Systems based on OpenServer before 5.0.4 (uname -X will tell you what you're running) require TLS597 from ftp://ftp.sco.com/TLS/ for C++ constructors and destructors to work right.

The system linker in (at least) 5.0.4 and 5.0.5 will sometimes do the wrong thing for a construct that GCC will emit for PIC code.  This can be seen as execution testsuite failures when using -fPIC on 921215-1.c, 931002-1.c, nestfunc-1.c, and gcov-1.c. For 5.0.5, an updated linker that will cure this problem is available.  You must install both ftp://ftp.sco.com/Supplements/rs505a/ and OSS499A.

The dynamic linker in OpenServer 5.0.5 (earlier versions may show the same problem) aborts on certain G77-compiled programs.  It's particularly likely to be triggered by building Fortran code with the -fPIC flag. Although it's conceivable that the error could be triggered by other code, only G77-compiled code has been observed to cause this abort. If you are getting core dumps immediately upon execution of your G77 program---and especially if it's compiled with -fPIC---try applying sco_osr5_g77.patch to your libf2c and rebuilding GCC. Affected faults, when analyzed in a debugger, will show a stack backtrace with a fault occurring in rtld() and the program running as /usr/lib/ld.so.1.  This problem has been reported to SCO engineering and will hopefully be addressed in later releases.

i?86-*-udk
==========

This target emulates the SCO Universal Development Kit and requires that package be installed.  (If it is installed, you will have a /udk/usr/ccs/bin/cc file present.)  It's very much like the i?86-*-unixware7* target but is meant to be used when hosting on a system where UDK isn't the default compiler such as OpenServer 5 or Unixware 2.  This target will generate binaries that will run on OpenServer, Unixware 2, or Unixware 7, with the same warnings and caveats as the SCO UDK.

This target is a little tricky to build because we have to distinguish it from the native tools (so it gets headers, startups, and libraries from the right place) while making the tools not think we're actually building a cross compiler.   The easiest way to do this is with a configure command like this:

         CC=/udk/usr/ccs/bin/cc /YOUR/PATH/TO/gcc/configure \
           --host=i686-pc-udk --target=i686-pc-udk --program-prefix=udk-

You should substitute i686 in the above command with the appropriate processor for your host.

After the usual make bootstrap and make install, you can then access the UDK-targeted GCC tools by adding udk- before the commonly known name.  For example, to invoke the C compiler, you would use udk-gcc. They will coexist peacefully with any native-target GCC tools you may have installed.

ia64-*-linux
============

IA-64 processor (also known as IPF, or Itanium Processor Family) running GNU/Linux.

The toolchain is not completely finished, so requirements will continue to change. GCC 3.0.1 and later require glibc 2.2.4. GCC 3.0.2 requires binutils from 2001-09-05 or later. GCC 3.0.1 requires binutils 2.11.1 or later.

None of the following versions of GCC has an ABI that is compatible with any of the other versions in this list, with the exception that Red Hat 2.96 and Trillian 000171 are compatible with each other: 3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717. This primarily affects C++ programs and programs that create shared libraries. Because of these ABI incompatibilities, GCC 3.0.2 is not recommended for user programs on GNU/Linux systems built using earlier compiler releases. GCC 3.0.2 is recommended for compiling linux, the kernel. GCC 3.0.2 is believed to be fully ABI compliant, and hence no more major ABI changes are expected.

*-lynx-lynxos
=============

LynxOS 2.2 and earlier comes with GCC 1.x already installed as /bin/gcc.  You should compile with this instead of /bin/cc. You can tell GCC to use the GNU assembler and linker, by specifying --with-gnu-as --with-gnu-ld when configuring.  These will produce COFF format object files and executables;  otherwise GCC will use the installed tools, which produce a.out format executables.

*-ibm-aix*
==========

AIX Make frequently has problems with GCC makefiles.  GNU Make 3.76 or newer is recommended to build on this platform.

Errors involving alloca when building GCC generally are due to an incorrect definition of CC in the Makefile or mixing files compiled with the native C compiler and GCC.  During the stage1 phase of the build, the native AIX compiler must be invoked as cc (not xlc).  Once configure has been informed of xlc, one needs to use make distclean to remove the configure cache files and ensure that CC environment variable does not provide a definition that will confuse configure. If this error occurs during stage2 or later, then the problem most likely is the version of Make (see above).

The GNU Assembler incorrectly reports that it supports WEAK symbols on AIX which causes GCC to try to utilize weak symbol functionality although it is not supported on the platform.  The native as and ld still are recommended.  The native AIX tools do interoperate with GCC.

Building libstdc++.a requires a fix for an AIX Assembler bug APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1).

libstdc++ in GCC 3.2 increments the major version number of the shared object and GCC installation places the libstdc++.a shared library in a common location which will overwrite the GCC 3.1 version of the shared library.  Applications either need to be re-linked against the new shared library or the GCC 3.1 version of the libstdc++ shared object needs to be available to the AIX runtime loader.  The GCC 3.1 libstdc++.so.4 shared object can be installed for runtime dynamic loading using the following steps to set the F_LOADONLY flag in the shared object for each multilib libstdc++.a installed:

Extract the shared object from each the GCC 3.1 libstdc++.a archive:

        % ar -x libstdc++.a libstdc++.so.4

Enable the F_LOADONLY flag so that the shared object will be available for runtime dynamic loading, but not linking:

        % strip -e libstdc++.so.4

Archive the runtime-only shared object in the GCC 3.2 libstdc++.a archive:

        % ar -q libstdc++.a libstdc++.so.4

Linking executables and shared libraries may produce warnings of duplicate symbols.  The assembly files generated by GCC for AIX always have included multiple symbol definitions for certain global variable and function declarations in the original program.  The warnings should not prevent the linker from producing a correct library or runnable executable.

AIX 4.3 utilizes a ``large format'' archive to support both 32-bit and 64-bit object modules.  The routines provided in AIX 4.3.0 and AIX 4.3.1 to parse archive libraries did not handle the new format correctly. These routines are used by GCC and result in error messages during linking such as ``not a COFF file''.  The version of the routines shipped with AIX 4.3.1 should work for a 32-bit environment.  The -g option of the archive command may be used to create archives of 32-bit objects using the original ``small format''.  A correct version of the routines is shipped with AIX 4.3.2 and above.

Some versions of the AIX binder (linker) can fail with a relocation overflow severe error when the -bbigtoc option is used to link GCC-produced object files into an executable that overflows the TOC.  A fix for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U455193.

The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core with a segmentation fault when invoked by any version of GCC.  A fix for APAR IX87327 is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U461879.  This fix is incorporated in AIX 4.3.3 and above.

The initial assembler shipped with AIX 4.3.0 generates incorrect object files.  A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS TO ASSEMBLE/BIND) is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U453956.  This fix is incorporated in AIX 4.3.1 and above.

AIX provides National Language Support (NLS).  Compilers and assemblers use NLS to support locale-specific representations of various data formats including floating-point numbers (e.g., .  vs , for separating decimal fractions).  There have been problems reported where GCC does not produce the same floating-point formats that the assembler expects.  If one encounters this problem, set the LANG environment variable to C or En_US.

By default, GCC for AIX 4.1 and above produces code that can be used on both Power or PowerPC processors.

A default can be specified with the -mcpu=CPU_TYPE switch and using the configure option --with-cpu-CPU_TYPE.

ip2k-*-elf
==========

Ubicom IP2022 micro controller. This configuration is intended for embedded systems. There are no standard Unix configurations.

Use configure --target=ip2k-elf --enable-languages=c to configure GCC.

m32r-*-elf
==========

Mitsubishi M32R processor. This configuration is intended for embedded systems.

m68000-hp-bsd
=============

HP 9000 series 200 running BSD.  Note that the C compiler that comes with this system cannot compile GCC; contact law@cygnus.com to get binaries of GCC for bootstrapping.

m6811-elf
=========

Motorola 68HC11 family micro controllers.  These are used in embedded applications.  There are no standard Unix configurations.

m6812-elf
=========

Motorola 68HC12 family micro controllers.  These are used in embedded applications.  There are no standard Unix configurations.

m68k-att-sysv
=============

AT&T 3b1, a.k.a. 7300 PC.  This version of GCC cannot be compiled with the system C compiler, which is too buggy. You will need to get a previous version of GCC and use it to bootstrap.  Binaries are available from the OSU-CIS archive, at ftp://archive.cis.ohio-state.edu/pub/att7300/.

m68k-crds-unos
==============

Use configure unos for building on Unos.

The Unos assembler is named casm instead of as.  For some strange reason linking /bin/as to /bin/casm changes the behavior, and does not work.  So, when installing GCC, you should install the following script as as in the subdirectory where the passes of GCC are installed:

     #!/bin/sh
     casm $*

The default Unos library is named libunos.a instead of libc.a.  To allow GCC to function, either change all references to -lc in gcc.c to -lunos or link /lib/libc.a to /lib/libunos.a.

When compiling GCC with the standard compiler, to overcome bugs in the support of alloca, do not use -O when making stage 2. Then use the stage 2 compiler with -O to make the stage 3 compiler.  This compiler will have the same characteristics as the usual stage 2 compiler on other systems.  Use it to make a stage 4 compiler and compare that with stage 3 to verify proper compilation.

(Perhaps simply defining ALLOCA in x-crds as described in the comments there will make the above paragraph superfluous.  Please inform us of whether this works.)

Unos uses memory segmentation instead of demand paging, so you will need a lot of memory.  5 Mb is barely enough if no other tasks are running. If linking cc1 fails, try putting the object files into a library and linking from that library.

m68k-hp-hpux
============

HP 9000 series 300 or 400 running HP-UX.  HP-UX version 8.0 has a bug in the assembler that prevents compilation of GCC.  This bug manifests itself during the first stage of compilation, while building libgcc2.a:

     _floatdisf
     cc1: warning: `-g' option not supported on this version of GCC
     cc1: warning: `-g1' option not supported on this version of GCC
     ./xgcc: Internal compiler error: program as got fatal signal 11

A patched version of the assembler is available as the file ftp://altdorf.ai.mit.edu/archive/cph/hpux-8.0-assembler.  If you have HP software support, the patch can also be obtained directly from HP, as described in the following note:

     This is the patched assembler, to patch SR#1653-010439, where the assembler aborts on floating point constants.

     The bug is not really in the assembler, but in the shared library version of the function ``cvtnum(3c)''.  The bug on ``cvtnum(3c)'' is SR#4701-078451.  Anyway, the attached assembler uses the archive library version of ``cvtnum(3c)'' and thus does not exhibit the bug.

This patch is also known as PHCO_4484.

In addition, if you wish to use gas, you must use gas version 2.1 or later, and you must use the GNU linker version 2.1 or later.  Earlier versions of gas relied upon a program which converted the gas output into the native HP-UX format, but that program has not been kept up to date.  gdb does not understand that native HP-UX format, so you must use gas if you wish to use gdb.

On HP-UX version 8.05, but not on 8.07 or more recent versions, the fixproto shell script triggers a bug in the system shell.  If you encounter this problem, upgrade your operating system or use BASH (the GNU shell) to run fixproto.  This bug will cause the fixproto program to report an error of the form:

     ./fixproto: sh internal 1K buffer overflow

To fix this, you can also change the first line of the fixproto script to look like:

     #!/bin/ksh

m68k-ncr-*
==========

On the Tower models 4N0 and 6N0, by default a process is not allowed to have more than one megabyte of memory.  GCC cannot compile itself (or many other programs) with -O in that much memory.

To solve this problem, reconfigure the kernel adding the following line to the configuration file:

     MAXUMEM = 4096

m68k-sun
========

Sun 3.  We do not provide a configuration file to use the Sun FPA by default, because programs that establish signal handlers for floating point traps inherently cannot work with the FPA.

m68k-sun-sunos4.1.1
===================

It is reported that you may need the GNU assembler on this platform.

mips-*-*
========

If on a MIPS system you get an error message saying ``does not have gp sections for all it's [sic] sectons [sic]'', don't worry about it.  This happens whenever you use GAS with the MIPS linker, but there is not really anything wrong, and it is okay to use the output file.  You can stop such warnings by installing the GNU linker.

It would be nice to extend GAS to produce the gp tables, but they are optional, and there should not be a warning about their absence.

mips-sgi-irix5
==============

This configuration has considerable problems, which will be fixed in a future release.

In order to compile GCC on an SGI running IRIX 5, the ``compiler_dev.hdr'' subsystem must be installed from the IDO CD-ROM supplied by Silicon Graphics.  It is also available for download from http://www.sgi.com/developers/devtools/apis/ido.html.

make compare may fail on version 5 of IRIX unless you add -save-temps to CFLAGS.  On these systems, the name of the assembler input file is stored in the object file, and that makes comparison fail if it differs between the stage1 and stage2 compilations.  The option -save-temps forces a fixed name to be used for the assembler input file, instead of a randomly chosen name in /tmp.  Do not add -save-temps unless the comparisons fail without that option.  If you do you -save-temps, you will have to manually delete the .i and .s files after each series of compilations.

If you use the MIPS C compiler to bootstrap, it may be necessary to increase its table size for switch statements with the -Wf,-XNg1500 option.  If you use the -O2 optimization option, you also need to use -Olimit 3000.

To enable debugging under IRIX 5, you must use GNU as 2.11.2 or later, and use the --with-gnu-as configure option when configuring GCC. GNU as is distributed as part of the binutils package. When using release 2.11.2, you need to apply a patch http://sources.redhat.com/ml/binutils/2001-07/msg00352.html which will be included in the next release of binutils.

When building GCC, the build process loops rebuilding cc1 over and over again.  This happens on mips-sgi-irix5.2, and possibly other platforms.  It has been reported that this is a known bug in the make shipped with IRIX 5.2.  We recommend you use GNU make instead of the vendor supplied make program; however, you may have success with smake on IRIX 5.2 if you do not have GNU make available.

mips-sgi-irix6
==============

If you are using IRIX cc as your bootstrap compiler, you must ensure that the N32 ABI is in use.  To test this, compile a simple C file with cc and then run file on the resulting object file.  The output should look like:

     test.o: ELF N32 MSB ...

If you see:

     test.o: ELF 32-bit MSB ...

or

     test.o: ELF 64-bit MSB ...

then your version of cc uses the O32 or N64 ABI by default.  You should set the environment variable CC to cc -n32 before configuring GCC.

If you want the resulting gcc to run on old 32-bit systems with the MIPS R4400 CPU, you need to ensure that only code for the mips3 instruction set architecture (ISA) is generated.  While GCC 3.x does this correctly, both GCC 2.95 and SGI's MIPSpro cc may change the ISA depending on the machine where GCC is built.  Using one of them as the bootstrap compiler may result in mips4 code, which won't run at all on mips3-only systems.  For the test program above, you should see:

     test.o: ELF N32 MSB mips-3 ...

If you get:

     test.o: ELF N32 MSB mips-4 ...

instead, you should set the environment variable CC to cc -n32 -mips3 or gcc -mips3 respectively before configuring GCC.

GCC on IRIX 6 is usually built to support both the N32 and N64 ABIs.  If you build GCC on a system that doesn't have the N64 libraries installed, you need to configure with --disable-multilib so GCC doesn't try to use them.  Look for /usr/lib64/libc.so.1 to see if you have the 64-bit libraries installed.

You must not use GNU as (which isn't built anyway as of binutils 2.11.2) on IRIX 6 platforms; doing so will only cause problems.

GCC does not currently support generating O32 ABI binaries in the mips-sgi-irix6 configurations.  It is possible to create a GCC with O32 ABI only support by configuring it for the mips-sgi-irix5 target and using a patched GNU as 2.11.2 as documented in the mips-sgi-irix5 section above.  Using the native assembler requires patches to GCC which will be included in a future release.  It is expected that O32 ABI support will be available again in a future release.

The --enable-threads option doesn't currently work, a patch is in preparation for a future release.  The --enable-libgcj option is disabled by default: IRIX 6 uses a very low default limit (20480) for the command line length.  Although libtool contains a workaround for this problem, at least the N64 libgcj is known not to build despite this, running into an internal error of the native ld.  A sure fix is to increase this limit (ncargs) to its maximum of 262144 bytes.  If you have root access, you can use the systune command to do this.

GCC does not correctly pass/return structures which are smaller than 16 bytes and which are not 8 bytes.  The problem is very involved and difficult to fix.  It affects a number of other targets also, but IRIX 6 is affected the most, because it is a 64-bit target, and 4 byte structures are common.  The exact problem is that structures are being padded at the wrong end, e.g. a 4 byte structure is loaded into the lower 4 bytes of the register when it should be loaded into the upper 4 bytes of the register.

GCC is consistent with itself, but not consistent with the SGI C compiler (and the SGI supplied runtime libraries), so the only failures that can happen are when there are library functions that take/return such structures. There are very few such library functions.  Currently this is known to affect inet_ntoa, inet_lnaof, inet_netof, inet_makeaddr, and semctl.  Until the bug is fixed, GCC contains workarounds for the known affected functions.

See http://freeware.sgi.com/ for more information about using GCC on IRIX platforms.

powerpc-*-*
===========

You can specify a default version for the -mcpu=CPU_TYPE switch by using the configure option --with-cpu-CPU_TYPE.

powerpc-*-darwin*
=================

PowerPC running Darwin (Mac OS X kernel).

GCC 3.0 does not support Darwin, but 3.1 and later releases will work.

Pre-installed versions of Mac OS X may not include any developer tools, meaning that you will not be able to build GCC from source.  Tool binaries are available at http://www.opensource.apple.com/projects/darwin (free registration required).

Versions of the assembler prior to ``cctools-364'' cannot handle the 4-argument form of rlwinm and related mask-using instructions.  Darwin 1.3 (Mac OS X 10.0) uses cctools-353 for instance.  To get cctools-364, check out cctools with tag Apple-364, build it, and install the assembler as usr/bin/as.  See http://www.opensource.apple.com/tools/cvs/docs.html for details.

Also, the default stack limit of 512K is too small, and a bootstrap will typically fail when self-compiling expr.c.  Set the stack to 800K or more, for instance by doing limit stack 800.  It's also convenient to use the GNU preprocessor instead of Apple's during the first stage of bootstrapping; this is automatic when doing make bootstrap, but to do it from the toplevel objdir you will need to say make CC='cc -no-cpp-precomp' bootstrap.

Note that the version of GCC shipped by Apple typically includes a number of extensions not available in a standard GCC release.  These extensions are generally specific to Mac programming.

powerpc-*-elf, powerpc-*-sysv4
==============================

PowerPC system in big endian mode, running System V.4.

powerpc-*-linux-gnu*
====================

You will need binutils 2.13.90.0.10 or newer for a working GCC.

powerpc-*-netbsd*
=================

PowerPC system in big endian mode running NetBSD.  To build the documentation you will need Texinfo version 4.1 (NetBSD 1.5.1 included Texinfo version 3.12).

powerpc-*-eabiaix
=================

Embedded PowerPC system in big endian mode with -mcall-aix selected as the default.

powerpc-*-eabisim
=================

Embedded PowerPC system in big endian mode for use in running under the PSIM simulator.

powerpc-*-eabi
==============

Embedded PowerPC system in big endian mode.

powerpcle-*-elf, powerpcle-*-sysv4
==================================

PowerPC system in little endian mode, running System V.4.

powerpcle-*-eabisim
===================

Embedded PowerPC system in little endian mode for use in running under the PSIM simulator.

powerpcle-*-eabi
================

Embedded PowerPC system in little endian mode.

powerpcle-*-winnt, powerpcle-*-pe
=================================

PowerPC system in little endian mode running Windows NT.

s390-*-linux*
=============

S/390 system running Linux for S/390.

s390x-*-linux*
==============

zSeries system (64-bit) running Linux for zSeries.

*-*-solaris2*
=============

Sun does not ship a C compiler with Solaris 2.  To bootstrap and install GCC you first have to install a pre-built compiler, see our binaries page for details.

The Solaris 2 /bin/sh will often fail to configure libstdc++-v3, boehm-gc or libjava.  If you encounter this problem, set CONFIG_SHELL to /bin/ksh in your environment before running configure.

Solaris 2 comes with a number of optional OS packages.  Some of these packages are needed to use GCC fully, namely SUNWarc, SUNWbtool, SUNWesu, SUNWhea, SUNWlibm, SUNWsprot, and SUNWtoo.  If you did not install all optional packages when installing Solaris 2, you will need to verify that the packages that GCC needs are installed.

To check whether an optional package is installed, use the pkginfo command.  To add an optional package, use the pkgadd command.  For further details, see the Solaris 2 documentation.

Trying to use the linker and other tools in /usr/ucb to install GCC has been observed to cause trouble. For example, the linker may hang indefinitely.  The fix is to remove /usr/ucb from your PATH.

All releases of GNU binutils prior to 2.11.2 have known bugs on this platform.  We recommend the use of GNU binutils 2.11.2 or the vendor tools (Sun as, Sun ld).

Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or newer: g++ will complain that types are missing.  These headers assume that omitting the type means int; this assumption worked for C89 but is wrong for C++, and is now wrong for C99 also.

g++ accepts such (invalid) constructs with the option -fpermissive; it will assume that any missing type is int (as defined by C89).

There are patches for Solaris 2.6 (105633-56 or newer for SPARC, 106248-42 or newer for Intel), Solaris 7 (108376-21 or newer for SPARC, 108377-20 for Intel), and Solaris 8 (108652-24 or newer for SPARC, 108653-22 for Intel) that fix this bug.

sparc-sun-solaris2*
===================

When GCC is configured to use binutils 2.11.2 or later the binaries produced are smaller than the ones produced using Sun's native tools; this difference is quite significant for binaries containing debugging information.

Sun as 4.x is broken in that it cannot cope with long symbol names. A typical error message might look similar to the following:

     /usr/ccs/bin/as: "/var/tmp/ccMsw135.s", line 11041: error:
       can't compute value of an expression involving an external symbol.

This is Sun bug 4237974.  This is fixed with patch 108908-02 for Solaris 2.6 and has been fixed in later (5.x) versions of the assembler, starting with Solaris 7.

Starting with Solaris 7, the operating system is capable of executing 64-bit SPARC V9 binaries.  GCC 3.1 and later properly supports this; the -m64 option enables 64-bit code generation. However, if all you want is code tuned for the UltraSPARC CPU, you should try the -mtune=ultrasparc option instead, which produces code that, unlike full 64-bit code, can still run on non-UltraSPARC machines.

When configuring on a Solaris 7 or later system that is running a kernel that supports only 32-bit binaries, one must configure with --disable-multilib, since we will not be able to build the 64-bit target libraries.

sparc-sun-solaris2.7
====================

Sun patch 107058-01 (1999-01-13) for Solaris 7/SPARC triggers a bug in the dynamic linker.  This problem (Sun bug 4210064) affects GCC 2.8 and later, including all EGCS releases.  Sun formerly recommended 107058-01 for all Solaris 7 users, but around 1999-09-01 it started to recommend it only for people who use Sun's compilers.

Here are some workarounds to this problem:

  * Do not install Sun patch 107058-01 until after Sun releases a complete patch for bug 4210064.  This is the simplest course to take, unless you must also use Sun's C compiler.  Unfortunately 107058-01 is preinstalled on some new Solaris 7-based hosts, so you may have to back it out.

  * Copy the original, unpatched Solaris 7 /usr/ccs/bin/as into /usr/local/lib/gcc-lib/sparc-sun-solaris2.7/3.1/as, adjusting the latter name to fit your local conventions and software version numbers.

  * Install Sun patch 106950-03 (1999-05-25) or later.  Nobody with both 107058-01 and 106950-03 installed has reported the bug with GCC and Sun's dynamic linker.  This last course of action is riskiest, for two reasons.  First, you must install 106950 on all hosts that run code generated by GCC; it doesn't suffice to install it only on the hosts that run GCC itself.  Second, Sun says that 106950-03 is only a partial fix for bug 4210064, but Sun doesn't know whether the partial fix is adequate for GCC.  Revision -08 or later should fix the bug.  The current (as of 2001-09-24) revision is -14, and is included in the Solaris 7 Recommended Patch Cluster.

sparc-sun-sunos4*
=================

A bug in the SunOS 4 linker will cause it to crash when linking -fPIC compiled objects (and will therefore not allow you to build shared libraries).

To fix this problem you can either use the most recent version of binutils or get the latest SunOS 4 linker patch (patch ID 100170-10) from Sun's patch site.

Sometimes on a Sun 4 you may observe a crash in the program genflags or genoutput while building GCC.  This is said to be due to a bug in sh.  You can probably get around it by running genflags or genoutput manually and then retrying the make.

sparc-unknown-linux-gnulibc1
============================

It has been reported that you might need binutils 2.8.1.0.23 for this platform, too.

sparc-*-linux*
==============

GCC versions 3.0 and higher require binutils 2.11.2 and glibc 2.2.4 or newer on this platform.  All earlier binutils and glibc releases mishandled unaligned relocations on sparc-*-* targets.

sparc64-*-*
===========

GCC version 2.95 is not able to compile code correctly for sparc64 targets.  Users of the Linux kernel, at least, can use the sparc32 program to start up a new shell invocation with an environment that causes configure to recognize (via uname -a) the system as sparc-*-* instead.

sparcv9-*-solaris2*
===================

The following compiler flags must be specified in the configure step in order to bootstrap this target with the Sun compiler:

        % CC="cc -xildoff -xarch=v9" SRCDIR/configure [OPTIONS] [TARGET]

-xildoff turns off the incremental linker, and -xarch=v9 specifies the v9 architecture to the Sun linker and assembler.

*-*-sysv*
=========

On System V release 3, you may get this error message while linking:

     ld fatal: failed to write symbol name SOMETHING
      in strings table for file WHATEVER

This probably indicates that the disk is full or your ulimit won't allow the file to be as large as it needs to be.

This problem can also result because the kernel parameter MAXUMEM is too small.  If so, you must regenerate the kernel and make the value much larger.  The default value is reported to be 1024; a value of 32768 is said to work.  Smaller values may also work.

On System V, if you get an error like this,

     /usr/local/lib/bison.simple: In function `yyparse':
     /usr/local/lib/bison.simple:625: virtual memory exhausted

that too indicates a problem with disk space, ulimit, or MAXUMEM.

On a System V release 4 system, make sure /usr/bin precedes /usr/ucb in PATH.  The cc command in /usr/ucb uses libraries which have bugs.

vax-dec-ultrix
==============

Don't try compiling with VAX C (vcc).  It produces incorrect code in some cases (for example, when alloca is used).

*-*-vxworks*
============

Support for VxWorks is in flux.  At present GCC supports only the very recent VxWorks 5.5 (aka Tornado 2.2) release, and only on PowerPC. We welcome patches for other architectures supported by VxWorks 5.5. Support for VxWorks AE would also be welcome; we believe this is merely a matter of writing an appropriate ``configlette'' (see below).  We are not interested in supporting older, a.out or COFF-based, versions of VxWorks in GCC 3.

VxWorks comes with an older version of GCC installed in $WIND_BASE/host; we recommend you do not overwrite it. Choose an installation PREFIX entirely outside $WIND_BASE. Before running configure, create the directories PREFIX and PREFIX/bin.  Link or copy the appropriate assembler, linker, etc. into PREFIX/bin, and set your PATH to include that directory while running both configure and make.

You must give configure the --with-headers=$WIND_BASE/target/h switch so that it can find the VxWorks system headers.  Since VxWorks is a cross compilation target only, you must also specify --target=TARGET. configure will attempt to create the directory PREFIX/TARGET/sys-include and copy files into it; make sure the user running configure has sufficient privilege to do so.

GCC's exception handling runtime requires a special ``configlette'' module, contrib/gthr_supp_vxw_5x.c.  Follow the instructions in that file to add the module to your kernel build.  (Future versions of VxWorks will incorporate this module.)

xtensa-*-elf
============

This target is intended for embedded Xtensa systems using the newlib C library.  It uses ELF but does not support shared objects.  Designed-defined instructions specified via the Tensilica Instruction Extension (TIE) language are only supported through inline assembly.

The Xtensa configuration information must be specified prior to building GCC.  The gcc/config/xtensa/xtensa-config.h header file contains the configuration information.  If you created your own Xtensa configuration with the Xtensa Processor Generator, the downloaded files include a customized copy of this header file, which you can use to replace the default header file.

xtensa-*-linux*
===============

This target is for Xtensa systems running GNU/Linux.  It supports ELF shared objects and the GNU C library (glibc).  It also generates position-independent code (PIC) regardless of whether the -fpic or -fPIC options are used.  In other respects, this target is the same as the xtensa-*-elf target.

Microsoft Windows (32-bit)
==========================

A port of GCC 2.95.x is included with the Cygwin environment.

Current (as of early 2001) snapshots of GCC will build under Cygwin without modification.

OS/2
====

GCC does not currently support OS/2.  However, Andrew Zabolotny has been working on a generic OS/2 port with pgcc.  The current code can be found at http://www.goof.com/pcg/os2/.

An older copy of GCC 2.8.1 is included with the EMX tools available at ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/.

Older systems
=============

GCC contains support files for many older (1980s and early 1990s) Unix variants.  For the most part, support for these systems has not been deliberately removed, but it has not been maintained for several years and may suffer from bitrot.

Starting with GCC 3.1, each release has a list of ``obsoleted'' systems. Support for these systems is still present in that release, but configure will fail unless the --enable-obsolete option is given.  Unless a maintainer steps forward, support for these systems will be removed from the next release of GCC.

Support for old systems as hosts for GCC can cause problems if the workarounds for compiler, library and operating system bugs affect the cleanliness or maintainability of the rest of GCC.  In some cases, to bring GCC up on such a system, if still possible with current GCC, may require first installing an old version of GCC which did work on that system, and using it to compile a more recent GCC, to avoid bugs in the vendor compiler.  Old releases of GCC 1 and GCC 2 are available in the old-releases directory on the GCC mirror sites.  Header bugs may generally be avoided using fixincludes, but bugs or deficiencies in libraries and the operating system may still cause problems.

Support for older systems as targets for cross-compilation is less problematic than support for them as hosts for GCC; if an enthusiast wishes to make such a target work again (including resurrecting any of the targets that never worked with GCC 2, starting from the last CVS version before they were removed), patches following the usual requirements would be likely to be accepted, since they should not affect the support for more modern targets.

For some systems, old versions of GNU binutils may also be useful, and are available from pub/binutils/old-releases on sources.redhat.com mirror sites.

Some of the information on specific systems above relates to such older systems, but much of the information about GCC on such systems (which may no longer be applicable to current GCC) is to be found in the GCC texinfo manual.

all ELF targets (SVR4, Solaris 2, etc.)
=======================================

C++ support is significantly better on ELF targets if you use the GNU linker; duplicate copies of inlines, vtables and template instantiations will be discarded automatically.

     [file install-old.texi not included]

     [file fdl.texi not included]