gcc/config/mips/elf.h

   1 /* Definitions of target machine for GNU compiler.  MIPS R3000 version with
   2    GOFAST floating point library.
   3    Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation, Inc.
   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 GNU CC; 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 /* Use ELF.  */
  23 #define OBJECT_FORMAT_ELF
  24
  25 /* Until we figure out what MIPS ELF targets normally use, just do
  26    stabs in ELF.  */
  27 #ifndef PREFERRED_DEBUGGING_TYPE
  28 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
  29 #endif
  30
  31 /* Mostly like ECOFF.  */
  32 #include "gofast.h"
  33 #include "mips/ecoff.h"
  34
  35 /* We need to use .esize and .etype instead of .size and .type to
  36    avoid conflicting with ELF directives.  */
  37 #undef PUT_SDB_SIZE
  38 #define PUT_SDB_SIZE(a)                                 \
  39 do {                                                    \
  40   extern FILE *asm_out_text_file;                       \
  41   fprintf (asm_out_text_file, "\t.esize\t");            \
  42   fprintf (asm_out_text_file, HOST_WIDE_INT_PRINT_DEC, (HOST_WIDE_INT) (a)); \
  43   fprintf (asm_out_text_file, ";");                     \
  44 } while (0)
  45
  46 #undef PUT_SDB_TYPE
  47 #define PUT_SDB_TYPE(a)                                 \
  48 do {                                                    \
  49   extern FILE *asm_out_text_file;                       \
  50   fprintf (asm_out_text_file, "\t.etype\t0x%x;", (a));  \
  51 } while (0)
  52
  53 /* Biggest alignment supported by the object file format of this
  54    machine.  Use this macro to limit the alignment which can be
  55    specified using the `__attribute__ ((aligned (N)))' construct.  If
  56    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
  57
  58 #undef MAX_OFILE_ALIGNMENT
  59 #define MAX_OFILE_ALIGNMENT (32768*8)
  60
  61 /* Switch into a generic section.  */
  62 #undef TARGET_ASM_NAMED_SECTION
  63 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
  64
  65 /* Given that Irix has it's own headers, not having TARGET_GAS here
  66    seems a mistake.  If we actually need to be prepared for file
  67    switching, then we need a custom TARGET_ASM_NAMED_SECTION too.  */
  68
  69 #undef TEXT_SECTION
  70 #define TEXT_SECTION()                          \
  71 do {                                            \
  72   if (TARGET_FILE_SWITCHING)                    \
  73     abort ();                                   \
  74   fputs (TEXT_SECTION_ASM_OP, asm_out_file);    \
  75   fputc ('\n', asm_out_file);                   \
  76 } while (0)
  77
  78 /* The following macro defines the format used to output the second
  79    operand of the .type assembler directive.  Different svr4 assemblers
  80    expect various different forms for this operand.  The one given here
  81    is just a default.  You may need to override it in your machine-
  82    specific tm.h file (depending upon the particulars of your assembler).  */
  83
  84 #define TYPE_OPERAND_FMT        "@%s"
  85
  86 /* Define the strings used for the special svr4 .type and .size directives.
  87    These strings generally do not vary from one system running svr4 to
  88    another, but if a given system (e.g. m88k running svr) needs to use
  89    different pseudo-op names for these, they may be overridden in the
  90    file which includes this one.  */
  91
  92 #undef TYPE_ASM_OP
  93 #undef SIZE_ASM_OP
  94 #define TYPE_ASM_OP     "\t.type\t"
  95 #define SIZE_ASM_OP     "\t.size\t"
  96
  97 /* If defined, a C expression whose value is a string containing the
  98    assembler operation to identify the following data as
  99    uninitialized global data.  If not defined, and neither
 100    `ASM_OUTPUT_BSS' nor `ASM_OUTPUT_ALIGNED_BSS' are defined,
 101    uninitialized global data will be output in the data section if
 102    `-fno-common' is passed, otherwise `ASM_OUTPUT_COMMON' will be
 103    used.  */
 104
 105 #ifndef BSS_SECTION_ASM_OP
 106 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
 107 #endif
 108
 109 #undef  SBSS_SECTION_ASM_OP
 110 #define SBSS_SECTION_ASM_OP     "\t.section .sbss"
 111
 112 /* Like `ASM_OUTPUT_BSS' except takes the required alignment as a
 113    separate, explicit argument.  If you define this macro, it is used
 114    in place of `ASM_OUTPUT_BSS', and gives you more flexibility in
 115    handling the required alignment of the variable.  The alignment is
 116    specified as the number of bits.
 117
 118    Try to use function `asm_output_aligned_bss' defined in file
 119    `varasm.c' when defining this macro.  */
 120 #ifndef ASM_OUTPUT_ALIGNED_BSS
 121 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 122 do {                                                                    \
 123   ASM_GLOBALIZE_LABEL (FILE, NAME);                                     \
 124   if (SIZE > 0 && SIZE <= mips_section_threshold)                       \
 125     sbss_section ();                                                    \
 126   else                                                                  \
 127     bss_section ();                                                     \
 128   ASM_OUTPUT_ALIGN (FILE, floor_log2 (ALIGN / BITS_PER_UNIT));          \
 129   last_assemble_variable_decl = DECL;                                   \
 130   ASM_DECLARE_OBJECT_NAME (FILE, NAME, DECL);                           \
 131   ASM_OUTPUT_SKIP (FILE, SIZE ? SIZE : 1);                              \
 132 } while (0)
 133 #endif
 134
 135 /* These macros generate the special .type and .size directives which
 136    are used to set the corresponding fields of the linker symbol table
 137    entries in an ELF object file under SVR4.  These macros also output
 138    the starting labels for the relevant functions/objects.  */
 139
 140 /* Write the extra assembler code needed to declare an object properly.  */
 141
 142 #undef ASM_DECLARE_OBJECT_NAME
 143 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)                       \
 144   do {                                                                  \
 145     fprintf (FILE, "%s", TYPE_ASM_OP);                          \
 146     assemble_name (FILE, NAME);                                         \
 147     putc (',', FILE);                                                   \
 148     fprintf (FILE, TYPE_OPERAND_FMT, "object");                         \
 149     putc ('\n', FILE);                                                  \
 150     size_directive_output = 0;                                          \
 151     if (!flag_inhibit_size_directive && DECL_SIZE (DECL))               \
 152       {                                                                 \
 153         size_directive_output = 1;                                      \
 154         fprintf (FILE, "%s", SIZE_ASM_OP);                              \
 155         assemble_name (FILE, NAME);                                     \
 156         fprintf (FILE, ",");                                            \
 157         fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,                         \
 158           int_size_in_bytes (TREE_TYPE (DECL)));                        \
 159         fprintf (FILE, "\n");                                           \
 160       }                                                                 \
 161     mips_declare_object (FILE, NAME, "", ":\n", 0);                     \
 162   } while (0)
 163
 164 /* Output the size directive for a decl in rest_of_decl_compilation
 165    in the case where we did not do so before the initializer.
 166    Once we find the error_mark_node, we know that the value of
 167    size_directive_output was set
 168    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 169
 170 #undef ASM_FINISH_DECLARE_OBJECT
 171 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 172 do {                                                                     \
 173      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 174      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 175          && ! AT_END && TOP_LEVEL                                        \
 176          && DECL_INITIAL (DECL) == error_mark_node                       \
 177          && !size_directive_output)                                      \
 178        {                                                                 \
 179          size_directive_output = 1;                                      \
 180          fprintf (FILE, "%s", SIZE_ASM_OP);                              \
 181          assemble_name (FILE, name);                                     \
 182          fprintf (FILE, ",");                                            \
 183          fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,                         \
 184                   int_size_in_bytes (TREE_TYPE (DECL)));                 \
 185          fprintf (FILE, "\n");                                           \
 186        }                                                                 \
 187    } while (0)
 188
 189 #define ASM_OUTPUT_DEF(FILE,LABEL1,LABEL2)                            \
 190  do { fputc ( '\t', FILE);                                            \
 191       assemble_name (FILE, LABEL1);                                   \
 192       fputs ( " = ", FILE);                                           \
 193       assemble_name (FILE, LABEL2);                                   \
 194       fputc ( '\n', FILE);                                            \
 195  } while (0)
 196
 197 /* Note about .weak vs. .weakext
 198    The mips native assemblers support .weakext, but not .weak.
 199    mips-elf gas supports .weak, but not .weakext.
 200    mips-elf gas has been changed to support both .weak and .weakext,
 201    but until that support is generally available, the 'if' below
 202    should serve.  */
 203
 204 #undef ASM_WEAKEN_LABEL
 205 #define ASM_WEAKEN_LABEL(FILE,NAME) ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,0)
 206 #define ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,VALUE)  \
 207  do {                                           \
 208   if (TARGET_GAS)                               \
 209       fputs ("\t.weak\t", FILE);                \
 210   else                                          \
 211       fputs ("\t.weakext\t", FILE);             \
 212   assemble_name (FILE, NAME);                   \
 213   if (VALUE)                                    \
 214     {                                           \
 215       fputc (' ', FILE);                        \
 216       assemble_name (FILE, VALUE);              \
 217     }                                           \
 218   fputc ('\n', FILE);                           \
 219  } while (0)
 220
 221 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 222 #undef UNIQUE_SECTION
 223 #define UNIQUE_SECTION(DECL,RELOC) \
 224   mips_unique_section ((DECL), (RELOC))
 225
 226 /* A list of other sections which the compiler might be "in" at any
 227    given time.  */
 228 #undef EXTRA_SECTIONS
 229 #define EXTRA_SECTIONS in_sdata, in_sbss, in_rdata
 230
 231 #undef EXTRA_SECTION_FUNCTIONS
 232 #define EXTRA_SECTION_FUNCTIONS                                         \
 233   SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP) \
 234   SECTION_FUNCTION_TEMPLATE(sbss_section, in_sbss, SBSS_SECTION_ASM_OP) \
 235   SECTION_FUNCTION_TEMPLATE(rdata_section, in_rdata, RDATA_SECTION_ASM_OP)
 236
 237 #define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP)                               \
 238 void FN ()                                                            \
 239 {                                                                     \
 240   if (in_section != ENUM)                                             \
 241     {                                                                 \
 242       fprintf (asm_out_file, "%s\n", OP);                             \
 243       in_section = ENUM;                                              \
 244     }                                                                 \
 245 }
 246
 247 /* On elf, we *do* have support for the .init and .fini sections, and we
 248    can put stuff in there to be executed before and after `main'.  We let
 249    crtstuff.c and other files know this by defining the following symbols.
 250    The definitions say how to change sections to the .init and .fini
 251    sections.  This is the same for all known elf assemblers.  */
 252
 253 #undef  INIT_SECTION_ASM_OP
 254 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 255 #undef  FINI_SECTION_ASM_OP
 256 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 257
 258 /* Don't set the target flags, this is done by the linker script */
 259 #undef LIB_SPEC
 260 #define LIB_SPEC ""
 261
 262 #undef  STARTFILE_SPEC
 263 #define STARTFILE_SPEC "crti%O%s crtbegin%O%s %{!mno-crt0:crt0%O%s}"
 264
 265 #undef  ENDFILE_SPEC
 266 #define ENDFILE_SPEC "crtend%O%s crtn%O%s"