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 Free Software Foundation, Inc.
   3    Contributed by Philip Blundell <philb@gnu.org>
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU CC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* Run-time Target Specification.  */
  23 #define TARGET_VERSION  fputs (" (ARM GNU/Linux with ELF)", stderr);
  24
  25 /* Do not assume anything about header files.  */
  26 #define NO_IMPLICIT_EXTERN_C
  27
  28 #ifndef SUBTARGET_DEFAULT_APCS26
  29 /* Default is to use APCS-32 mode.  */
  30 # define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_MMU_TRAPS)
  31 # ifdef SUBTARGET_OLD_LINKER
  32 #  define SUBTARGET_EXTRA_LINK_SPEC     \
  33         " %{mapcs-26:-m elf32arm26} %{!mapcs-26:-m elf32arm}"
  34 # else  /* new linker */
  35 #  define SUBTARGET_EXTRA_LINK_SPEC     \
  36         " %{mapcs-26:-m armelf_linux26} %{!mapcs-26:-m armelf_linux} -p"
  37 # endif
  38 # define SUBTARGET_EXTRA_ASM_SPEC       \
  39         " %{mapcs-26:-mapcs-26} %{!mapcs-26:-mapcs-32}"
  40 # define MULTILIB_DEFAULTS \
  41         { "marm", "mlittle-endian", "mhard-float", "mapcs-32", "mno-thumb-interwork" }
  42 # define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  43 #else   /* default is APCS-26 */
  44 # define TARGET_DEFAULT (ARM_FLAG_MMU_TRAPS)
  45 # ifdef SUBTARGET_OLD_LINKER
  46 #  define SUBTARGET_EXTRA_LINK_SPEC     \
  47         " %{mapcs-32:-m elf32arm} %{!mapcs-32:-m elf32arm26}"
  48 # else  /* new linker */
  49 #  define SUBTARGET_EXTRA_LINK_SPEC     \
  50         " %{mapcs-32:-m armelf_linux} %{!mapcs-32:-m armelf_linux26} -p"
  51 # endif
  52 # define SUBTARGET_EXTRA_ASM_SPEC       \
  53         " %{mapcs-32:-mapcs-32} %{!mapcs-32:-mapcs-26}"
  54 # define MULTILIB_DEFAULTS \
  55         { "marm", "mlittle-endian", "mhard-float", "mapcs-26", "mno-thumb-interwork" }
  56 #endif
  57
  58 /* This was defined in linux.h.  Define it here also. */
  59 #undef  DEFAULT_VTABLE_THUNKS
  60 #define DEFAULT_VTABLE_THUNKS   1
  61
  62 /* Handle #pragma weak and #pragma pack.  */
  63 #define HANDLE_SYSV_PRAGMA
  64
  65 /* Now we define the strings used to build the spec file.  */
  66 #define LIB_SPEC \
  67   "%{shared: -lc} \
  68    %{!shared: %{pthread:-lpthread} \
  69    %{profile:-lc_p} %{!profile: -lc}}"
  70
  71
  72 #define LIBGCC_SPEC "%{msoft-float:-lfloat} -lgcc"
  73
  74 /* Provide a STARTFILE_SPEC appropriate for GNU/Linux.  Here we add
  75    the GNU/Linux magical crtbegin.o file (see crtstuff.c) which
  76    provides part of the support for getting C++ file-scope static
  77    object constructed before entering `main'. */
  78
  79 #define STARTFILE_SPEC \
  80   "%{!shared: \
  81      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} \
  82                        %{!p:%{profile:gcrt1.o%s} \
  83                          %{!profile:crt1.o%s}}}} \
  84    crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}"
  85
  86 /* Provide a ENDFILE_SPEC appropriate for GNU/Linux.  Here we tack on
  87    the GNU/Linux magical crtend.o file (see crtstuff.c) which
  88    provides part of the support for getting C++ file-scope static
  89    object constructed before entering `main', followed by a normal
  90    GNU/Linux "finalizer" file, `crtn.o'.  */
  91
  92 #define ENDFILE_SPEC \
  93   "%{!shared:crtend.o%s} %{shared:crtendS.o%s} crtn.o%s"
  94
  95 #define LINK_SPEC "%{h*} %{version:-v} \
  96    %{b} %{Wl,*:%*} \
  97    %{static:-Bstatic} \
  98    %{shared:-shared} \
  99    %{symbolic:-Bsymbolic} \
 100    %{rdynamic:-export-dynamic} \
 101    %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2} \
 102    -X \
 103    %{mbig-endian:-EB}" \
 104    SUBTARGET_EXTRA_LINK_SPEC
 105
 106 #undef  CPP_PREDEFINES
 107 #define CPP_PREDEFINES \
 108 "-Dunix -D__arm__ -Dlinux -D__ELF__ \
 109 -Asystem(unix) -Asystem(posix) -Acpu(arm) -Amachine(arm)"
 110
 111 /* Allow #sccs in preprocessor.  */
 112 #define SCCS_DIRECTIVE
 113
 114 #define USER_LABEL_PREFIX       ""      /* For ELF the default is no underscores */
 115 #define LOCAL_LABEL_PREFIX      "."
 116
 117 /* Attach a special .ident directive to the end of the file to identify
 118    the version of GCC which compiled this code.  */
 119 #define IDENT_ASM_OP    ".ident"
 120
 121 /* Output #ident as a .ident.  */
 122 #define ASM_OUTPUT_IDENT(FILE, NAME) \
 123   fprintf (FILE, "\t%s\t\"%s\"\n", IDENT_ASM_OP, NAME);
 124
 125 #ifdef IDENTIFY_WITH_IDENT
 126 #define ASM_IDENTIFY_GCC(FILE) /* nothing */
 127 #define ASM_IDENTIFY_LANGUAGE(FILE)                     \
 128  fprintf (FILE, "\t%s \"GCC (%s) %s\"\n", IDENT_ASM_OP, \
 129          lang_identify (), version_string)
 130 #else
 131 #define ASM_FILE_END(FILE)                                      \
 132 do {                                                            \
 133      if (!flag_no_ident)                                        \
 134         fprintf ((FILE), "\t%s\t\"GCC: (GNU) %s\"\n",           \
 135                  IDENT_ASM_OP, version_string);                 \
 136    } while (0)
 137 #endif
 138
 139 /* Support const sections and the ctors and dtors sections for g++.
 140    Note that there appears to be two different ways to support const
 141    sections at the moment.  You can either #define the symbol
 142    READONLY_DATA_SECTION (giving it some code which switches to the
 143    readonly data section) or else you can #define the symbols
 144    EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
 145    SELECT_RTX_SECTION.  We do both here just to be on the safe side.  */
 146 #define USE_CONST_SECTION       1
 147
 148 /* Support for Constructors and Destructors.  */
 149 #define READONLY_DATA_SECTION() const_section ()
 150
 151 /* A default list of other sections which we might be "in" at any given
 152    time.  For targets that use additional sections (e.g. .tdesc) you
 153    should override this definition in the target-specific file which
 154    includes this file.  */
 155 #define SUBTARGET_EXTRA_SECTIONS in_const,
 156
 157 /* A default list of extra section function definitions.  For targets
 158    that use additional sections (e.g. .tdesc) you should override this
 159    definition in the target-specific file which includes this file.  */
 160 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS       CONST_SECTION_FUNCTION
 161
 162 extern void text_section ();
 163
 164 #define CONST_SECTION_ASM_OP    ".section\t.rodata"
 165
 166 #define CONST_SECTION_FUNCTION                                          \
 167 void                                                                    \
 168 const_section ()                                                        \
 169 {                                                                       \
 170   if (!USE_CONST_SECTION)                                               \
 171     text_section ();                                                    \
 172   else if (in_section != in_const)                                      \
 173     {                                                                   \
 174       fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);             \
 175       in_section = in_const;                                            \
 176     }                                                                   \
 177 }
 178
 179 /* Switch into a generic section.
 180    This is currently only used to support section attributes.
 181
 182    We make the section read-only and executable for a function decl,
 183    read-only for a const data decl, and writable for a non-const data decl.  */
 184 #define ASM_OUTPUT_SECTION_NAME(FILE, DECL, NAME, RELOC) \
 185   fprintf (FILE, ".section\t%s,\"%s\",%%progbits\n", NAME, \
 186            (DECL) && TREE_CODE (DECL) == FUNCTION_DECL ? "ax" : \
 187            (DECL) && DECL_READONLY_SECTION (DECL, RELOC) ? "a" : "aw")
 188
 189 /* A C statement or statements to switch to the appropriate
 190    section for output of DECL.  DECL is either a `VAR_DECL' node
 191    or a constant of some sort.  RELOC indicates whether forming
 192    the initial value of DECL requires link-time relocations.  */
 193 #define SELECT_SECTION(DECL,RELOC)                                      \
 194 {                                                                       \
 195   if (TREE_CODE (DECL) == STRING_CST)                                   \
 196     {                                                                   \
 197       if (! flag_writable_strings)                                      \
 198         const_section ();                                               \
 199       else                                                              \
 200         data_section ();                                                \
 201     }                                                                   \
 202   else if (TREE_CODE (DECL) == VAR_DECL)                                \
 203     {                                                                   \
 204       if ((flag_pic && RELOC)                                           \
 205           || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)          \
 206           || !DECL_INITIAL (DECL)                                       \
 207           || (DECL_INITIAL (DECL) != error_mark_node                    \
 208               && !TREE_CONSTANT (DECL_INITIAL (DECL))))                 \
 209         data_section ();                                                \
 210       else                                                              \
 211         const_section ();                                               \
 212     }                                                                   \
 213   else                                                                  \
 214     const_section ();                                                   \
 215 }
 216
 217 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 218 #define UNIQUE_SECTION_P(DECL)   (DECL_ONE_ONLY (DECL))
 219
 220 #define UNIQUE_SECTION(DECL, RELOC)                             \
 221   do                                                            \
 222     {                                                           \
 223       int len;                                                  \
 224       char * name;                                              \
 225       char * string;                                            \
 226       char * prefix;                                            \
 227                                                                 \
 228       name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));   \
 229                                                                 \
 230       if (! DECL_ONE_ONLY (DECL))                               \
 231         {                                                       \
 232           prefix = ".";                                         \
 233           if (TREE_CODE (DECL) == FUNCTION_DECL)                \
 234             prefix = ".text.";                                  \
 235           else if (DECL_READONLY_SECTION (DECL, RELOC))         \
 236             prefix = ".rodata.";                                \
 237           else                                                  \
 238             prefix = ".data.";                                  \
 239         }                                                       \
 240       else if (TREE_CODE (DECL) == FUNCTION_DECL)               \
 241         prefix = ".gnu.linkonce.t.";                            \
 242       else if (DECL_READONLY_SECTION (DECL, RELOC))             \
 243         prefix = ".gnu.linkonce.r.";                            \
 244       else                                                      \
 245         prefix = ".gnu.linkonce.d.";                            \
 246                                                                 \
 247       len = strlen (name) + strlen (prefix);                    \
 248       string = alloca (len + 1);                                \
 249       sprintf (string, "%s%s", prefix, name);                   \
 250                                                                 \
 251       DECL_SECTION_NAME (DECL) = build_string (len, string);    \
 252     }                                                           \
 253   while (0)
 254
 255 /* A C statement or statements to switch to the appropriate
 256    section for output of RTX in mode MODE.  RTX is some kind
 257    of constant in RTL.  The argument MODE is redundant except
 258    in the case of a `const_int' rtx.  Currently, these always
 259    go into the const section.  */
 260 #define SELECT_RTX_SECTION(MODE,RTX) const_section ()
 261
 262 /* On svr4, we *do* have support for the .init and .fini sections, and we
 263    can put stuff in there to be executed before and after `main'.  We let
 264    crtstuff.c and other files know this by defining the following symbols.
 265    The definitions say how to change sections to the .init and .fini
 266    sections.  This is the same for all known svr4 assemblers.  */
 267 #define INIT_SECTION_ASM_OP     ".section\t.init"
 268 #define FINI_SECTION_ASM_OP     ".section\t.fini"
 269
 270
 271 /* This is how we tell the assembler that a symbol is weak.  */
 272 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 273   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 274        fputc ('\n', FILE); } while (0)
 275
 276 /* This is how we tell the assembler that two symbols have the same value.  */
 277
 278 #define ASM_OUTPUT_DEF(FILE,NAME1,NAME2) \
 279   do { assemble_name (FILE, NAME1);      \
 280        fputs (" = ", FILE);              \
 281        assemble_name (FILE, NAME2);      \
 282        fputc ('\n', FILE); } while (0)
 283
 284 /* Make DWARF2 an option, but keep DBX as the default for now.
 285    Use -gdwarf-2 to turn on DWARF2.  */
 286 #define DWARF2_DEBUGGING_INFO
 287 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
 288
 289 /* Get the standard ELF stabs definitions.  */
 290 #include "dbxelf.h"
 291
 292 #include "arm/elf.h"
 293 #include "arm/linux-gas.h"
 294
 295 /* NWFPE always understands FPA instructions.  */
 296 #undef  FP_DEFAULT
 297 #define FP_DEFAULT FP_SOFT3
 298
 299 /* Call the function profiler with a given profile label.  */
 300 #undef  ARM_FUNCTION_PROFILER
 301 #define ARM_FUNCTION_PROFILER(STREAM, LABELNO)                          \
 302 {                                                                       \
 303   fprintf (STREAM, "\tbl\tmcount%s\n", NEED_PLT_RELOC ? "(PLT)" : "");  \
 304 }
 305
 306 #undef  CC1_SPEC
 307 #define CC1_SPEC "%{profile:-p}"