gcc/config/arm/linux-elf.h

   1 /* Definitions for ARM running Linux-based GNU systems using ELF
   2    Copyright (C) 1993, 1994, 1997, 1998, 1999, 2000, 2001
   3    Free Software Foundation, Inc.
   4    Contributed by Philip Blundell <philb@gnu.org>
   5
   6 This file is part of GNU CC.
   7
   8 GNU CC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GNU CC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.  */
  22
  23 /* Run-time Target Specification.  */
  24 #define TARGET_VERSION  fputs (" (ARM GNU/Linux with ELF)", stderr);
  25
  26 /* Do not assume anything about header files.  */
  27 #define NO_IMPLICIT_EXTERN_C
  28
  29 /* Default is to use APCS-32 mode.  */
  30 #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_MMU_TRAPS)
  31 #define SUBTARGET_EXTRA_LINK_SPEC " -m armelf_linux -p"
  32 #define MULTILIB_DEFAULTS \
  33         { "marm", "mlittle-endian", "mhard-float", "mapcs-32", "mno-thumb-interwork" }
  34 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  35
  36 /* This was defined in linux.h.  Define it here also. */
  37 #undef  DEFAULT_VTABLE_THUNKS
  38 #define DEFAULT_VTABLE_THUNKS   1
  39
  40 /* Handle #pragma weak and #pragma pack.  */
  41 #define HANDLE_SYSV_PRAGMA
  42
  43 /* Now we define the strings used to build the spec file.  */
  44 #define LIB_SPEC \
  45   "%{shared: -lc} \
  46    %{!shared: %{pthread:-lpthread} \
  47    %{profile:-lc_p} %{!profile: -lc}}"
  48
  49
  50 #define LIBGCC_SPEC "%{msoft-float:-lfloat} -lgcc"
  51
  52 /* Provide a STARTFILE_SPEC appropriate for GNU/Linux.  Here we add
  53    the GNU/Linux magical crtbegin.o file (see crtstuff.c) which
  54    provides part of the support for getting C++ file-scope static
  55    object constructed before entering `main'. */
  56
  57 #define STARTFILE_SPEC \
  58   "%{!shared: \
  59      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} \
  60                        %{!p:%{profile:gcrt1.o%s} \
  61                          %{!profile:crt1.o%s}}}} \
  62    crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}"
  63
  64 /* Provide a ENDFILE_SPEC appropriate for GNU/Linux.  Here we tack on
  65    the GNU/Linux magical crtend.o file (see crtstuff.c) which
  66    provides part of the support for getting C++ file-scope static
  67    object constructed before entering `main', followed by a normal
  68    GNU/Linux "finalizer" file, `crtn.o'.  */
  69
  70 #define ENDFILE_SPEC \
  71   "%{!shared:crtend.o%s} %{shared:crtendS.o%s} crtn.o%s"
  72
  73 #define LINK_SPEC "%{h*} %{version:-v} \
  74    %{b} %{Wl,*:%*} \
  75    %{static:-Bstatic} \
  76    %{shared:-shared} \
  77    %{symbolic:-Bsymbolic} \
  78    %{rdynamic:-export-dynamic} \
  79    %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2} \
  80    -X \
  81    %{mbig-endian:-EB}" \
  82    SUBTARGET_EXTRA_LINK_SPEC
  83
  84 #undef  CPP_PREDEFINES
  85 #define CPP_PREDEFINES \
  86 "-Dunix -Dlinux -D__ELF__ \
  87 -Asystem=unix -Asystem=posix -Acpu=arm -Amachine=arm"
  88
  89 /* Allow #sccs in preprocessor.  */
  90 #define SCCS_DIRECTIVE
  91
  92 #define USER_LABEL_PREFIX       ""      /* For ELF the default is no underscores */
  93 #define LOCAL_LABEL_PREFIX      "."
  94
  95 #define IDENT_ASM_OP    "\t.ident\t"
  96
  97 /* Output #ident as a .ident.  */
  98 #define ASM_OUTPUT_IDENT(FILE, NAME) \
  99   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
 100
 101 /* Support const sections and the ctors and dtors sections for g++.
 102    Note that there appears to be two different ways to support const
 103    sections at the moment.  You can either #define the symbol
 104    READONLY_DATA_SECTION (giving it some code which switches to the
 105    readonly data section) or else you can #define the symbols
 106    EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
 107    SELECT_RTX_SECTION.  We do both here just to be on the safe side.  */
 108 #define USE_CONST_SECTION       1
 109
 110 /* Support for Constructors and Destructors.  */
 111 #define READONLY_DATA_SECTION() const_section ()
 112
 113 /* A default list of other sections which we might be "in" at any given
 114    time.  For targets that use additional sections (e.g. .tdesc) you
 115    should override this definition in the target-specific file which
 116    includes this file.  */
 117 #define SUBTARGET_EXTRA_SECTIONS in_const,
 118
 119 /* A default list of extra section function definitions.  For targets
 120    that use additional sections (e.g. .tdesc) you should override this
 121    definition in the target-specific file which includes this file.  */
 122 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS       CONST_SECTION_FUNCTION
 123
 124 #define CONST_SECTION_ASM_OP    "\t.section\t.rodata"
 125
 126 #define CONST_SECTION_FUNCTION                                          \
 127 void                                                                    \
 128 const_section ()                                                        \
 129 {                                                                       \
 130   if (!USE_CONST_SECTION)                                               \
 131     text_section ();                                                    \
 132   else if (in_section != in_const)                                      \
 133     {                                                                   \
 134       fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);             \
 135       in_section = in_const;                                            \
 136     }                                                                   \
 137 }
 138
 139 /* Switch into a generic section.
 140    This is currently only used to support section attributes.
 141
 142    We make the section read-only and executable for a function decl,
 143    read-only for a const data decl, and writable for a non-const data decl.  */
 144 #define ASM_OUTPUT_SECTION_NAME(FILE, DECL, NAME, RELOC) \
 145   fprintf (FILE, ".section\t%s,\"%s\",%%progbits\n", NAME, \
 146            (DECL) && TREE_CODE (DECL) == FUNCTION_DECL ? "ax" : \
 147            (DECL) && DECL_READONLY_SECTION (DECL, RELOC) ? "a" : "aw")
 148
 149 /* A C statement or statements to switch to the appropriate
 150    section for output of DECL.  DECL is either a `VAR_DECL' node
 151    or a constant of some sort.  RELOC indicates whether forming
 152    the initial value of DECL requires link-time relocations.  */
 153 #define SELECT_SECTION(DECL,RELOC)                                      \
 154 {                                                                       \
 155   if (TREE_CODE (DECL) == STRING_CST)                                   \
 156     {                                                                   \
 157       if (! flag_writable_strings)                                      \
 158         const_section ();                                               \
 159       else                                                              \
 160         data_section ();                                                \
 161     }                                                                   \
 162   else if (TREE_CODE (DECL) == VAR_DECL)                                \
 163     {                                                                   \
 164       if ((flag_pic && RELOC)                                           \
 165           || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)          \
 166           || !DECL_INITIAL (DECL)                                       \
 167           || (DECL_INITIAL (DECL) != error_mark_node                    \
 168               && !TREE_CONSTANT (DECL_INITIAL (DECL))))                 \
 169         data_section ();                                                \
 170       else                                                              \
 171         const_section ();                                               \
 172     }                                                                   \
 173   else                                                                  \
 174     const_section ();                                                   \
 175 }
 176
 177 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 178 #define UNIQUE_SECTION_P(DECL)   (DECL_ONE_ONLY (DECL))
 179
 180 #define UNIQUE_SECTION(DECL, RELOC)                             \
 181   do                                                            \
 182     {                                                           \
 183       int len;                                                  \
 184       char * name;                                              \
 185       char * string;                                            \
 186       char * prefix;                                            \
 187                                                                 \
 188       name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));   \
 189                                                                 \
 190       if (! DECL_ONE_ONLY (DECL))                               \
 191         {                                                       \
 192           prefix = ".";                                         \
 193           if (TREE_CODE (DECL) == FUNCTION_DECL)                \
 194             prefix = ".text.";                                  \
 195           else if (DECL_READONLY_SECTION (DECL, RELOC))         \
 196             prefix = ".rodata.";                                \
 197           else                                                  \
 198             prefix = ".data.";                                  \
 199         }                                                       \
 200       else if (TREE_CODE (DECL) == FUNCTION_DECL)               \
 201         prefix = ".gnu.linkonce.t.";                            \
 202       else if (DECL_READONLY_SECTION (DECL, RELOC))             \
 203         prefix = ".gnu.linkonce.r.";                            \
 204       else                                                      \
 205         prefix = ".gnu.linkonce.d.";                            \
 206                                                                 \
 207       len = strlen (name) + strlen (prefix);                    \
 208       string = alloca (len + 1);                                \
 209       sprintf (string, "%s%s", prefix, name);                   \
 210                                                                 \
 211       DECL_SECTION_NAME (DECL) = build_string (len, string);    \
 212     }                                                           \
 213   while (0)
 214
 215 /* A C statement or statements to switch to the appropriate
 216    section for output of RTX in mode MODE.  RTX is some kind
 217    of constant in RTL.  The argument MODE is redundant except
 218    in the case of a `const_int' rtx.  Currently, these always
 219    go into the const section.  */
 220 #define SELECT_RTX_SECTION(MODE,RTX) const_section ()
 221
 222 /* On svr4, we *do* have support for the .init and .fini sections, and we
 223    can put stuff in there to be executed before and after `main'.  We let
 224    crtstuff.c and other files know this by defining the following symbols.
 225    The definitions say how to change sections to the .init and .fini
 226    sections.  This is the same for all known svr4 assemblers.  */
 227 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 228 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 229
 230
 231 /* This is how we tell the assembler that a symbol is weak.  */
 232 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 233   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 234        fputc ('\n', FILE); } while (0)
 235
 236 /* This is how we tell the assembler that two symbols have the same value.  */
 237
 238 #define ASM_OUTPUT_DEF(FILE,NAME1,NAME2) \
 239   do { assemble_name (FILE, NAME1);      \
 240        fputs (" = ", FILE);              \
 241        assemble_name (FILE, NAME2);      \
 242        fputc ('\n', FILE); } while (0)
 243
 244 /* Make DWARF2 an option, but keep DBX as the default for now.
 245    Use -gdwarf-2 to turn on DWARF2.  */
 246 #define DWARF2_DEBUGGING_INFO
 247 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
 248
 249 /* Get the standard ELF stabs definitions.  */
 250 #include "dbxelf.h"
 251
 252 #include "arm/elf.h"
 253 #include "arm/linux-gas.h"
 254
 255 /* NWFPE always understands FPA instructions.  */
 256 #undef  FP_DEFAULT
 257 #define FP_DEFAULT FP_SOFT3
 258
 259 /* Call the function profiler with a given profile label.  */
 260 #undef  ARM_FUNCTION_PROFILER
 261 #define ARM_FUNCTION_PROFILER(STREAM, LABELNO)                          \
 262 {                                                                       \
 263   fprintf (STREAM, "\tbl\tmcount%s\n", NEED_PLT_RELOC ? "(PLT)" : "");  \
 264 }
 265
 266 #undef  CC1_SPEC
 267 #define CC1_SPEC "%{profile:-p}"