gcc/config/mips/elf64.h

   1 /* Definitions of target machine for GNU compiler.  MIPS R4000 version with
   2    GOFAST floating point library.
   3    Copyright (C) 1994, 1995, 1996, 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 #define OBJECT_FORMAT_ELF
  23
  24 /* Default to -mips3.  */
  25 #define TARGET_DEFAULT MASK_FLOAT64|MASK_64BIT
  26 #define MIPS_ISA_DEFAULT 3
  27
  28 /* Until we figure out what MIPS ELF targets normally use, just do
  29    stabs in ELF.  */
  30 #ifndef PREFERRED_DEBUGGING_TYPE
  31 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
  32 #endif
  33
  34 /* US Software GOFAST library support.  */
  35 #include "gofast.h"
  36 #define INIT_SUBTARGET_OPTABS INIT_GOFAST_OPTABS
  37
  38 #include "mips/mips.h"
  39
  40 #undef CPP_PREDEFINES
  41 #define CPP_PREDEFINES "-Dmips -DMIPSEB -DR4000 -D_mips -D_MIPSEB -D_R4000"
  42
  43 /* I would rather put this in CPP_PREDEFINES, but the gcc driver
  44    doesn't handle -U options in CPP_PREDEFINES.  */
  45 #undef SUBTARGET_CPP_SPEC
  46 #define SUBTARGET_CPP_SPEC "\
  47 %{!mips1:%{!mips2:-U__mips -D__mips=3 -D__mips64}}"
  48
  49 /* Use memcpy, et. al., rather than bcopy.  */
  50 #define TARGET_MEM_FUNCTIONS
  51
  52 /* Biggest alignment supported by the object file format of this
  53    machine.  Use this macro to limit the alignment which can be
  54    specified using the `__attribute__ ((aligned (N)))' construct.  If
  55    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
  56
  57 #undef MAX_OFILE_ALIGNMENT
  58 #define MAX_OFILE_ALIGNMENT (32768*8)
  59
  60 /* We need to use .esize and .etype instead of .size and .type to
  61    avoid conflicting with ELF directives.  */
  62 #undef PUT_SDB_SIZE
  63 #define PUT_SDB_SIZE(a)                                 \
  64 do {                                                    \
  65   extern FILE *asm_out_text_file;                       \
  66   fprintf (asm_out_text_file, "\t.esize\t%d;", (a));    \
  67 } while (0)
  68
  69 #undef PUT_SDB_TYPE
  70 #define PUT_SDB_TYPE(a)                                 \
  71 do {                                                    \
  72   extern FILE *asm_out_text_file;                       \
  73   fprintf (asm_out_text_file, "\t.etype\t0x%x;", (a));  \
  74 } while (0)
  75
  76 /* Switch into a generic section.  */
  77 #undef TARGET_ASM_NAMED_SECTION
  78 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
  79
  80 /* Given that Irix has it's own headers, not having TARGET_GAS here
  81    seems a mistake.  If we actually need to be prepared for file
  82    switching, then we need a custom TARGET_ASM_NAMED_SECTION too.  */
  83
  84 #undef TEXT_SECTION
  85 #define TEXT_SECTION()                          \
  86 do {                                            \
  87   if (TARGET_FILE_SWITCHING)                    \
  88     abort ();                                   \
  89   fputs (TEXT_SECTION_ASM_OP, asm_out_file);    \
  90   fputc ('\n', asm_out_file);                   \
  91 } while (0)
  92
  93 /* The following macro defines the format used to output the second
  94    operand of the .type assembler directive.  Different svr4 assemblers
  95    expect various different forms for this operand.  The one given here
  96    is just a default.  You may need to override it in your machine-
  97    specific tm.h file (depending upon the particulars of your assembler).  */
  98
  99 #define TYPE_OPERAND_FMT        "@%s"
 100
 101 /* Define the strings used for the special svr4 .type and .size directives.
 102    These strings generally do not vary from one system running svr4 to
 103    another, but if a given system (e.g. m88k running svr) needs to use
 104    different pseudo-op names for these, they may be overridden in the
 105    file which includes this one.  */
 106
 107 #undef TYPE_ASM_OP
 108 #undef SIZE_ASM_OP
 109 #define TYPE_ASM_OP     "\t.type\t"
 110 #define SIZE_ASM_OP     "\t.size\t"
 111
 112 /* These macros generate the special .type and .size directives which
 113    are used to set the corresponding fields of the linker symbol table
 114    entries in an ELF object file under SVR4.  These macros also output
 115    the starting labels for the relevant functions/objects.  */
 116
 117 /* Write the extra assembler code needed to declare an object properly.  */
 118
 119 #undef ASM_DECLARE_OBJECT_NAME
 120 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)                       \
 121   do {                                                                  \
 122     fprintf (FILE, "%s", TYPE_ASM_OP);                                  \
 123     assemble_name (FILE, NAME);                                         \
 124     putc (',', FILE);                                                   \
 125     fprintf (FILE, TYPE_OPERAND_FMT, "object");                         \
 126     putc ('\n', FILE);                                                  \
 127     size_directive_output = 0;                                          \
 128     if (!flag_inhibit_size_directive && DECL_SIZE (DECL))               \
 129       {                                                                 \
 130         size_directive_output = 1;                                      \
 131         fprintf (FILE, "%s", SIZE_ASM_OP);                              \
 132         assemble_name (FILE, NAME);                                     \
 133         fprintf (FILE, ",%d\n",  int_size_in_bytes (TREE_TYPE (DECL))); \
 134       }                                                                 \
 135     mips_declare_object (FILE, NAME, "", ":\n", 0);                     \
 136   } while (0)
 137
 138 /* Output the size directive for a decl in rest_of_decl_compilation
 139    in the case where we did not do so before the initializer.
 140    Once we find the error_mark_node, we know that the value of
 141    size_directive_output was set
 142    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 143
 144 #undef ASM_FINISH_DECLARE_OBJECT
 145 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 146 do {                                                                     \
 147      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 148      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 149          && ! AT_END && TOP_LEVEL                                        \
 150          && DECL_INITIAL (DECL) == error_mark_node                       \
 151          && !size_directive_output)                                      \
 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    } while (0)
 162
 163 #define ASM_OUTPUT_DEF(FILE,LABEL1,LABEL2)                            \
 164  do { fputc ( '\t', FILE);                                            \
 165       assemble_name (FILE, LABEL1);                                   \
 166       fputs ( " = ", FILE);                                           \
 167       assemble_name (FILE, LABEL2);                                   \
 168       fputc ( '\n', FILE);                                            \
 169  } while (0)
 170
 171 /* Note about .weak vs. .weakext
 172    The mips native assemblers support .weakext, but not .weak.
 173    mips-elf gas supports .weak, but not .weakext.
 174    mips-elf gas has been changed to support both .weak and .weakext,
 175    but until that support is generally available, the 'if' below
 176    should serve. */
 177
 178 #undef ASM_WEAKEN_LABEL
 179 #define ASM_WEAKEN_LABEL(FILE,NAME) ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,0)
 180 #define ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,VALUE)  \
 181  do {                                           \
 182   if (TARGET_GAS)                               \
 183       fputs ("\t.weak\t", FILE);                \
 184   else                                          \
 185       fputs ("\t.weakext\t", FILE);             \
 186   assemble_name (FILE, NAME);                   \
 187   if (VALUE)                                    \
 188     {                                           \
 189       fputc (' ', FILE);                        \
 190       assemble_name (FILE, VALUE);              \
 191     }                                           \
 192   fputc ('\n', FILE);                           \
 193  } while (0)
 194
 195 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 196 #undef UNIQUE_SECTION
 197 #define UNIQUE_SECTION(DECL,RELOC)                                         \
 198 do {                                                                       \
 199   int len, size, sec;                                                      \
 200   char *name, *string, *prefix;                                            \
 201   static char *prefixes[4][2] = {                                          \
 202     { ".text.", ".gnu.linkonce.t." },                                      \
 203     { ".rodata.", ".gnu.linkonce.r." },                                    \
 204     { ".data.", ".gnu.linkonce.d." },                                      \
 205     { ".sdata.", ".gnu.linkonce.s." }                                      \
 206   };                                                                       \
 207                                                                            \
 208   name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));                  \
 209   size = int_size_in_bytes (TREE_TYPE (decl));                             \
 210                                                                            \
 211   /* Determine the base section we are interested in:                      \
 212      0=text, 1=rodata, 2=data, 3=sdata, [4=bss].  */                       \
 213   if (TREE_CODE (DECL) == FUNCTION_DECL)                                   \
 214     sec = 0;                                                               \
 215   else if (DECL_INITIAL (DECL) == 0                                        \
 216            || DECL_INITIAL (DECL) == error_mark_node)                      \
 217     sec = 2;                                                               \
 218   else if ((TARGET_EMBEDDED_PIC || TARGET_MIPS16)                          \
 219       && TREE_CODE (decl) == STRING_CST                                    \
 220       && !flag_writable_strings)                                           \
 221     {                                                                      \
 222       /* For embedded position independent code, put constant strings      \
 223          in the text section, because the data section is limited to       \
 224          64K in size.  For mips16 code, put strings in the text            \
 225          section so that a PC relative load instruction can be used to     \
 226          get their address.  */                                            \
 227       sec = 0;                                                             \
 228     }                                                                      \
 229   else if (TARGET_EMBEDDED_DATA)                                           \
 230     {                                                                      \
 231       /* For embedded applications, always put an object in read-only data \
 232          if possible, in order to reduce RAM usage.  */                    \
 233                                                                            \
 234       if (DECL_READONLY_SECTION (DECL, RELOC))                             \
 235         sec = 1;                                                           \
 236       else if (size > 0 && size <= mips_section_threshold)                 \
 237         sec = 3;                                                           \
 238       else                                                                 \
 239         sec = 2;                                                           \
 240     }                                                                      \
 241   else                                                                     \
 242     {                                                                      \
 243       /* For hosted applications, always put an object in small data if    \
 244          possible, as this gives the best performance.  */                 \
 245                                                                            \
 246       if (size > 0 && size <= mips_section_threshold)                      \
 247         sec = 3;                                                           \
 248       else if (DECL_READONLY_SECTION (DECL, RELOC))                        \
 249         sec = 1;                                                           \
 250       else                                                                 \
 251         sec = 2;                                                           \
 252     }                                                                      \
 253                                                                            \
 254   prefix = prefixes[sec][DECL_ONE_ONLY (DECL)];                            \
 255   len = strlen (name) + strlen (prefix);                                   \
 256   string = alloca (len + 1);                                               \
 257   sprintf (string, "%s%s", prefix, name);                                  \
 258                                                                            \
 259   DECL_SECTION_NAME (DECL) = build_string (len, string);                   \
 260 } while (0)
 261
 262 /* A list of other sections which the compiler might be "in" at any
 263    given time.  */
 264 #undef EXTRA_SECTIONS
 265 #define EXTRA_SECTIONS in_sdata, in_rdata
 266
 267 #undef EXTRA_SECTION_FUNCTIONS
 268 #define EXTRA_SECTION_FUNCTIONS                                         \
 269   SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP) \
 270   SECTION_FUNCTION_TEMPLATE(rdata_section, in_rdata, RDATA_SECTION_ASM_OP)
 271
 272 #define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP)                               \
 273 void FN ()                                                            \
 274 {                                                                     \
 275   if (in_section != ENUM)                                             \
 276     {                                                                 \
 277       fprintf (asm_out_file, "%s\n", OP);                             \
 278       in_section = ENUM;                                              \
 279     }                                                                 \
 280 }
 281
 282 /* On elf, we *do* have support for the .init and .fini sections, and we
 283    can put stuff in there to be executed before and after `main'.  We let
 284    crtstuff.c and other files know this by defining the following symbols.
 285    The definitions say how to change sections to the .init and .fini
 286    sections.  This is the same for all known elf assemblers.  */
 287
 288 #undef  INIT_SECTION_ASM_OP
 289 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 290 #undef  FINI_SECTION_ASM_OP
 291 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 292
 293 /* Don't set the target flags, this is done by the linker script */
 294 #undef LIB_SPEC
 295 #define LIB_SPEC ""
 296
 297 #undef  STARTFILE_SPEC
 298 #define STARTFILE_SPEC "crti%O%s crtbegin%O%s %{!mno-crt0:crt0%O%s}"
 299
 300 #undef  ENDFILE_SPEC
 301 #define ENDFILE_SPEC "crtend%O%s crtn%O%s"