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 #define MAX_OFILE_ALIGNMENT (32768*8)
  58
  59 /* We need to use .esize and .etype instead of .size and .type to
  60    avoid conflicting with ELF directives.  */
  61 #undef PUT_SDB_SIZE
  62 #define PUT_SDB_SIZE(a)                                 \
  63 do {                                                    \
  64   extern FILE *asm_out_text_file;                       \
  65   fprintf (asm_out_text_file, "\t.esize\t%d;", (a));    \
  66 } while (0)
  67
  68 #undef PUT_SDB_TYPE
  69 #define PUT_SDB_TYPE(a)                                 \
  70 do {                                                    \
  71   extern FILE *asm_out_text_file;                       \
  72   fprintf (asm_out_text_file, "\t.etype\t0x%x;", (a));  \
  73 } while (0)
  74
  75 /* A C statement to output something to the assembler file to switch to section
  76    NAME for object DECL which is either a FUNCTION_DECL, a VAR_DECL or
  77    NULL_TREE.  Some target formats do not support arbitrary sections.  Do not
  78    define this macro in such cases.  */
  79
  80 #define ASM_OUTPUT_SECTION_NAME(F, DECL, NAME, RELOC) \
  81 do {                                                            \
  82   extern FILE *asm_out_text_file;                               \
  83   if ((DECL) && TREE_CODE (DECL) == FUNCTION_DECL)              \
  84     fprintf (asm_out_text_file, "\t.section %s,\"ax\",@progbits\n", (NAME)); \
  85   else if ((DECL) && DECL_READONLY_SECTION (DECL, RELOC))       \
  86     fprintf (F, "\t.section %s,\"a\",@progbits\n", (NAME));     \
  87   else if (! strcmp (NAME, ".bss"))                             \
  88     fprintf (F, "\t.section %s,\"aw\",@nobits\n", (NAME));      \
  89   else                                                          \
  90     fprintf (F, "\t.section %s,\"aw\",@progbits\n", (NAME));    \
  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, ",%d\n", int_size_in_bytes (TREE_TYPE (DECL)));  \
 157        }                                                                 \
 158    } while (0)
 159
 160 #define ASM_OUTPUT_DEF(FILE,LABEL1,LABEL2)                            \
 161  do { fputc ( '\t', FILE);                                            \
 162       assemble_name (FILE, LABEL1);                                   \
 163       fputs ( " = ", FILE);                                           \
 164       assemble_name (FILE, LABEL2);                                   \
 165       fputc ( '\n', FILE);                                            \
 166  } while (0)
 167
 168 /* Note about .weak vs. .weakext
 169    The mips native assemblers support .weakext, but not .weak.
 170    mips-elf gas supports .weak, but not .weakext.
 171    mips-elf gas has been changed to support both .weak and .weakext,
 172    but until that support is generally available, the 'if' below
 173    should serve. */
 174
 175 #define ASM_WEAKEN_LABEL(FILE,NAME) ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,0)
 176 #define ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,VALUE)  \
 177  do {                                           \
 178   if (TARGET_GAS)                               \
 179       fputs ("\t.weak\t", FILE);                \
 180   else                                          \
 181       fputs ("\t.weakext\t", FILE);             \
 182   assemble_name (FILE, NAME);                   \
 183   if (VALUE)                                    \
 184     {                                           \
 185       fputc (' ', FILE);                        \
 186       assemble_name (FILE, VALUE);              \
 187     }                                           \
 188   fputc ('\n', FILE);                           \
 189  } while (0)
 190
 191 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 192 #undef UNIQUE_SECTION_P
 193 #define UNIQUE_SECTION_P(DECL) (DECL_ONE_ONLY (DECL))
 194 #define UNIQUE_SECTION(DECL,RELOC)                                         \
 195 do {                                                                       \
 196   int len, size, sec;                                                      \
 197   char *name, *string, *prefix;                                            \
 198   static char *prefixes[4][2] = {                                          \
 199     { ".text.", ".gnu.linkonce.t." },                                      \
 200     { ".rodata.", ".gnu.linkonce.r." },                                    \
 201     { ".data.", ".gnu.linkonce.d." },                                      \
 202     { ".sdata.", ".gnu.linkonce.s." }                                      \
 203   };                                                                       \
 204                                                                            \
 205   name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (DECL));                  \
 206   size = int_size_in_bytes (TREE_TYPE (decl));                             \
 207                                                                            \
 208   /* Determine the base section we are interested in:                      \
 209      0=text, 1=rodata, 2=data, 3=sdata, [4=bss].  */                       \
 210   if (TREE_CODE (DECL) == FUNCTION_DECL)                                   \
 211     sec = 0;                                                               \
 212   else if (DECL_INITIAL (DECL) == 0                                        \
 213            || DECL_INITIAL (DECL) == error_mark_node)                      \
 214     sec = 2;                                                               \
 215   else if ((TARGET_EMBEDDED_PIC || TARGET_MIPS16)                          \
 216       && TREE_CODE (decl) == STRING_CST                                    \
 217       && !flag_writable_strings)                                           \
 218     {                                                                      \
 219       /* For embedded position independent code, put constant strings      \
 220          in the text section, because the data section is limited to       \
 221          64K in size.  For mips16 code, put strings in the text            \
 222          section so that a PC relative load instruction can be used to     \
 223          get their address.  */                                            \
 224       sec = 0;                                                             \
 225     }                                                                      \
 226   else if (TARGET_EMBEDDED_DATA)                                           \
 227     {                                                                      \
 228       /* For embedded applications, always put an object in read-only data \
 229          if possible, in order to reduce RAM usage.  */                    \
 230                                                                            \
 231       if (DECL_READONLY_SECTION (DECL, RELOC))                             \
 232         sec = 1;                                                           \
 233       else if (size > 0 && size <= mips_section_threshold)                 \
 234         sec = 3;                                                           \
 235       else                                                                 \
 236         sec = 2;                                                           \
 237     }                                                                      \
 238   else                                                                     \
 239     {                                                                      \
 240       /* For hosted applications, always put an object in small data if    \
 241          possible, as this gives the best performance.  */                 \
 242                                                                            \
 243       if (size > 0 && size <= mips_section_threshold)                      \
 244         sec = 3;                                                           \
 245       else if (DECL_READONLY_SECTION (DECL, RELOC))                        \
 246         sec = 1;                                                           \
 247       else                                                                 \
 248         sec = 2;                                                           \
 249     }                                                                      \
 250                                                                            \
 251   prefix = prefixes[sec][DECL_ONE_ONLY (DECL)];                            \
 252   len = strlen (name) + strlen (prefix);                                   \
 253   string = alloca (len + 1);                                               \
 254   sprintf (string, "%s%s", prefix, name);                                  \
 255                                                                            \
 256   DECL_SECTION_NAME (DECL) = build_string (len, string);                   \
 257 } while (0)
 258
 259 /* Support the ctors/dtors and other sections.  */
 260
 261 /* Define the names of and pseudo-ops used to switch to the .ctors and
 262    .dtors sections.
 263
 264    Note that we want to give these sections the SHF_WRITE attribute
 265    because these sections will actually contain data (i.e. tables of
 266    addresses of functions in the current root executable or shared library
 267    file) and, in the case of a shared library, the relocatable addresses
 268    will have to be properly resolved/relocated (and then written into) by
 269    the dynamic linker when it actually attaches the given shared library
 270    to the executing process.  (Note that on SVR4, you may wish to use the
 271    `-z text' option to the ELF linker, when building a shared library, as
 272    an additional check that you are doing everything right.  But if you do
 273    use the `-z text' option when building a shared library, you will get
 274    errors unless the .ctors and .dtors sections are marked as writable
 275    via the SHF_WRITE attribute.)  */
 276
 277 #define CTORS_SECTION_NAME      ".ctors"
 278 #define CTORS_SECTION_ASM_OP    "\t.section\t.ctors,\"aw\""
 279 #define DTORS_SECTION_NAME      ".dtors"
 280 #define DTORS_SECTION_ASM_OP    "\t.section\t.dtors,\"aw\""
 281
 282 /* There's no point providing a default definition of __CTOR_LIST__
 283    since people are expected either to use crtbegin.o, or an equivalent,
 284    or provide their own definition.  */
 285 #define CTOR_LISTS_DEFINED_EXTERNALLY
 286
 287 /* A list of other sections which the compiler might be "in" at any
 288    given time.  */
 289 #undef EXTRA_SECTIONS
 290 #define EXTRA_SECTIONS in_sdata, in_rdata, in_ctors, in_dtors
 291
 292 #define INVOKE__main
 293
 294 #undef EXTRA_SECTION_FUNCTIONS
 295 #define EXTRA_SECTION_FUNCTIONS                                         \
 296   SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP) \
 297   SECTION_FUNCTION_TEMPLATE(rdata_section, in_rdata, RDATA_SECTION_ASM_OP) \
 298   SECTION_FUNCTION_TEMPLATE(ctors_section, in_ctors, CTORS_SECTION_ASM_OP) \
 299   SECTION_FUNCTION_TEMPLATE(dtors_section, in_dtors, DTORS_SECTION_ASM_OP)
 300
 301 #define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP)                               \
 302 void FN ()                                                            \
 303 {                                                                     \
 304   if (in_section != ENUM)                                             \
 305     {                                                                 \
 306       fprintf (asm_out_file, "%s\n", OP);                             \
 307       in_section = ENUM;                                              \
 308     }                                                                 \
 309 }
 310
 311
 312 /* A C statement (sans semicolon) to output an element in the table of
 313    global constructors.  */
 314 #define ASM_OUTPUT_CONSTRUCTOR(FILE,NAME)                             \
 315   do {                                                                \
 316     ctors_section ();                                                 \
 317     fprintf (FILE, "\t%s\t", (Pmode == SImode) ? ".word" : ".dword"); \
 318     assemble_name (FILE, NAME);                                       \
 319     fprintf (FILE, "\n");                                             \
 320   } while (0)
 321
 322
 323 /* A C statement (sans semicolon) to output an element in the table of
 324    global destructors.  */
 325 #define ASM_OUTPUT_DESTRUCTOR(FILE,NAME)                              \
 326   do {                                                                \
 327     dtors_section ();                                                 \
 328     fprintf (FILE, "\t%s\t", (Pmode == SImode) ? ".word" : ".dword"); \
 329     assemble_name (FILE, NAME);                                       \
 330     fprintf (FILE, "\n");                                             \
 331   } while (0)
 332
 333 #define CTOR_LIST_BEGIN                                               \
 334 func_ptr __CTOR_LIST__ __attribute__((section(CTORS_SECTION_NAME))) = \
 335   (func_ptr) (-1)
 336
 337 #define CTOR_LIST_END                                                 \
 338 func_ptr __CTOR_END__ __attribute__((section(CTORS_SECTION_NAME))) =  \
 339   (func_ptr) 0
 340
 341 #define DTOR_LIST_BEGIN                                               \
 342 func_ptr __DTOR_LIST__ __attribute__((section(DTORS_SECTION_NAME))) = \
 343   (func_ptr) (-1)
 344
 345 #define DTOR_LIST_END                                                 \
 346 func_ptr __DTOR_END__ __attribute__((section(DTORS_SECTION_NAME))) =  \
 347   (func_ptr) 0
 348
 349 /* Don't set the target flags, this is done by the linker script */
 350 #undef LIB_SPEC
 351 #define LIB_SPEC ""
 352
 353 #undef  STARTFILE_SPEC
 354 #define STARTFILE_SPEC "crtbegin%O%s %{!mno-crt0:crt0%O%s}"
 355
 356 #undef  ENDFILE_SPEC
 357 #define ENDFILE_SPEC "crtend%O%s"