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 /* Attach a special .ident directive to the end of the file to identify
  96    the version of GCC which compiled this code.  */
  97 #define IDENT_ASM_OP    "\t.ident\t"
  98
  99 /* Output #ident as a .ident.  */
 100 #define ASM_OUTPUT_IDENT(FILE, NAME) \
 101   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
 102
 103 #ifdef IDENTIFY_WITH_IDENT
 104 #define ASM_IDENTIFY_GCC(FILE) /* nothing */
 105 #define ASM_IDENTIFY_LANGUAGE(FILE)                     \
 106  fprintf (FILE, "%s\"GCC (%s) %s\"\n", IDENT_ASM_OP,    \
 107          lang_identify (), version_string)
 108 #else
 109 #define ASM_FILE_END(FILE)                                      \
 110 do {                                                            \
 111      if (!flag_no_ident)                                        \
 112         fprintf ((FILE), "%s\"GCC: (GNU) %s\"\n",               \
 113                  IDENT_ASM_OP, version_string);                 \
 114    } while (0)
 115 #endif
 116
 117 /* Support const sections and the ctors and dtors sections for g++.
 118    Note that there appears to be two different ways to support const
 119    sections at the moment.  You can either #define the symbol
 120    READONLY_DATA_SECTION (giving it some code which switches to the
 121    readonly data section) or else you can #define the symbols
 122    EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
 123    SELECT_RTX_SECTION.  We do both here just to be on the safe side.  */
 124 #define USE_CONST_SECTION       1
 125
 126 /* Support for Constructors and Destructors.  */
 127 #define READONLY_DATA_SECTION() const_section ()
 128
 129 /* A default list of other sections which we might be "in" at any given
 130    time.  For targets that use additional sections (e.g. .tdesc) you
 131    should override this definition in the target-specific file which
 132    includes this file.  */
 133 #define SUBTARGET_EXTRA_SECTIONS in_const,
 134
 135 /* A default list of extra section function definitions.  For targets
 136    that use additional sections (e.g. .tdesc) you should override this
 137    definition in the target-specific file which includes this file.  */
 138 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS       CONST_SECTION_FUNCTION
 139
 140 #define CONST_SECTION_ASM_OP    "\t.section\t.rodata"
 141
 142 #define CONST_SECTION_FUNCTION                                          \
 143 void                                                                    \
 144 const_section ()                                                        \
 145 {                                                                       \
 146   if (!USE_CONST_SECTION)                                               \
 147     text_section ();                                                    \
 148   else if (in_section != in_const)                                      \
 149     {                                                                   \
 150       fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);             \
 151       in_section = in_const;                                            \
 152     }                                                                   \
 153 }
 154
 155 /* Switch into a generic section.
 156    This is currently only used to support section attributes.
 157
 158    We make the section read-only and executable for a function decl,
 159    read-only for a const data decl, and writable for a non-const data decl.  */
 160 #define ASM_OUTPUT_SECTION_NAME(FILE, DECL, NAME, RELOC) \
 161   fprintf (FILE, ".section\t%s,\"%s\",%%progbits\n", NAME, \
 162            (DECL) && TREE_CODE (DECL) == FUNCTION_DECL ? "ax" : \
 163            (DECL) && DECL_READONLY_SECTION (DECL, RELOC) ? "a" : "aw")
 164
 165 /* A C statement or statements to switch to the appropriate
 166    section for output of DECL.  DECL is either a `VAR_DECL' node
 167    or a constant of some sort.  RELOC indicates whether forming
 168    the initial value of DECL requires link-time relocations.  */
 169 #define SELECT_SECTION(DECL,RELOC)                                      \
 170 {                                                                       \
 171   if (TREE_CODE (DECL) == STRING_CST)                                   \
 172     {                                                                   \
 173       if (! flag_writable_strings)                                      \
 174         const_section ();                                               \
 175       else                                                              \
 176         data_section ();                                                \
 177     }                                                                   \
 178   else if (TREE_CODE (DECL) == VAR_DECL)                                \
 179     {                                                                   \
 180       if ((flag_pic && RELOC)                                           \
 181           || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)          \
 182           || !DECL_INITIAL (DECL)                                       \
 183           || (DECL_INITIAL (DECL) != error_mark_node                    \
 184               && !TREE_CONSTANT (DECL_INITIAL (DECL))))                 \
 185         data_section ();                                                \
 186       else                                                              \
 187         const_section ();                                               \
 188     }                                                                   \
 189   else                                                                  \
 190     const_section ();                                                   \
 191 }
 192
 193 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 194 #define UNIQUE_SECTION_P(DECL)   (DECL_ONE_ONLY (DECL))
 195
 196 #define UNIQUE_SECTION(DECL, RELOC)                             \
 197   do                                                            \
 198     {                                                           \
 199       int len;                                                  \
 200       char * name;                                              \
 201       char * string;                                            \
 202       char * prefix;                                            \
 203                                                                 \
 204       name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));   \
 205                                                                 \
 206       if (! DECL_ONE_ONLY (DECL))                               \
 207         {                                                       \
 208           prefix = ".";                                         \
 209           if (TREE_CODE (DECL) == FUNCTION_DECL)                \
 210             prefix = ".text.";                                  \
 211           else if (DECL_READONLY_SECTION (DECL, RELOC))         \
 212             prefix = ".rodata.";                                \
 213           else                                                  \
 214             prefix = ".data.";                                  \
 215         }                                                       \
 216       else if (TREE_CODE (DECL) == FUNCTION_DECL)               \
 217         prefix = ".gnu.linkonce.t.";                            \
 218       else if (DECL_READONLY_SECTION (DECL, RELOC))             \
 219         prefix = ".gnu.linkonce.r.";                            \
 220       else                                                      \
 221         prefix = ".gnu.linkonce.d.";                            \
 222                                                                 \
 223       len = strlen (name) + strlen (prefix);                    \
 224       string = alloca (len + 1);                                \
 225       sprintf (string, "%s%s", prefix, name);                   \
 226                                                                 \
 227       DECL_SECTION_NAME (DECL) = build_string (len, string);    \
 228     }                                                           \
 229   while (0)
 230
 231 /* A C statement or statements to switch to the appropriate
 232    section for output of RTX in mode MODE.  RTX is some kind
 233    of constant in RTL.  The argument MODE is redundant except
 234    in the case of a `const_int' rtx.  Currently, these always
 235    go into the const section.  */
 236 #define SELECT_RTX_SECTION(MODE,RTX) const_section ()
 237
 238 /* On svr4, we *do* have support for the .init and .fini sections, and we
 239    can put stuff in there to be executed before and after `main'.  We let
 240    crtstuff.c and other files know this by defining the following symbols.
 241    The definitions say how to change sections to the .init and .fini
 242    sections.  This is the same for all known svr4 assemblers.  */
 243 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 244 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 245
 246
 247 /* This is how we tell the assembler that a symbol is weak.  */
 248 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 249   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 250        fputc ('\n', FILE); } while (0)
 251
 252 /* This is how we tell the assembler that two symbols have the same value.  */
 253
 254 #define ASM_OUTPUT_DEF(FILE,NAME1,NAME2) \
 255   do { assemble_name (FILE, NAME1);      \
 256        fputs (" = ", FILE);              \
 257        assemble_name (FILE, NAME2);      \
 258        fputc ('\n', FILE); } while (0)
 259
 260 /* Make DWARF2 an option, but keep DBX as the default for now.
 261    Use -gdwarf-2 to turn on DWARF2.  */
 262 #define DWARF2_DEBUGGING_INFO
 263 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
 264
 265 /* Get the standard ELF stabs definitions.  */
 266 #include "dbxelf.h"
 267
 268 #include "arm/elf.h"
 269 #include "arm/linux-gas.h"
 270
 271 /* NWFPE always understands FPA instructions.  */
 272 #undef  FP_DEFAULT
 273 #define FP_DEFAULT FP_SOFT3
 274
 275 /* Call the function profiler with a given profile label.  */
 276 #undef  ARM_FUNCTION_PROFILER
 277 #define ARM_FUNCTION_PROFILER(STREAM, LABELNO)                          \
 278 {                                                                       \
 279   fprintf (STREAM, "\tbl\tmcount%s\n", NEED_PLT_RELOC ? "(PLT)" : "");  \
 280 }
 281
 282 #undef  CC1_SPEC
 283 #define CC1_SPEC "%{profile:-p}"