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, 2002 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 #undef  OBJECT_FORMAT_COFF
  24 #undef  EXTENDED_COFF
  25 #define OBJECT_FORMAT_ELF
  26
  27 /* ??? Move all SDB stuff into separate header file.  */
  28 #undef  SDB_DEBUGGING_INFO
  29
  30 #define DBX_DEBUGGING_INFO 1
  31 #define DWARF2_DEBUGGING_INFO 1
  32
  33 #undef  PREFERRED_DEBUGGING_TYPE
  34 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  35
  36 #undef  SUBTARGET_ASM_DEBUGGING_SPEC
  37 #define SUBTARGET_ASM_DEBUGGING_SPEC "-g0"
  38
  39 /* Biggest alignment supported by the object file format of this
  40    machine.  Use this macro to limit the alignment which can be
  41    specified using the `__attribute__ ((aligned (N)))' construct.  If
  42    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
  43
  44 #undef  MAX_OFILE_ALIGNMENT
  45 #define MAX_OFILE_ALIGNMENT (32768*8)
  46
  47 /* Switch into a generic section.  */
  48 #undef  TARGET_ASM_NAMED_SECTION
  49 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
  50
  51 /* Given that Irix has it's own headers, not having TARGET_GAS here
  52    seems a mistake.  If we actually need to be prepared for file
  53    switching, then we need a custom TARGET_ASM_NAMED_SECTION too.  */
  54
  55 #undef  TEXT_SECTION
  56 #define TEXT_SECTION()                          \
  57 do {                                            \
  58   if (TARGET_FILE_SWITCHING)                    \
  59     abort ();                                   \
  60   fputs (TEXT_SECTION_ASM_OP, asm_out_file);    \
  61   fputc ('\n', asm_out_file);                   \
  62 } while (0)
  63
  64 /* The following macro defines the format used to output the second
  65    operand of the .type assembler directive.  Different svr4 assemblers
  66    expect various different forms for this operand.  The one given here
  67    is just a default.  You may need to override it in your machine-
  68    specific tm.h file (depending upon the particulars of your assembler).  */
  69
  70 #define TYPE_OPERAND_FMT        "@%s"
  71
  72 /* Define the strings used for the special svr4 .type and .size directives.
  73    These strings generally do not vary from one system running svr4 to
  74    another, but if a given system (e.g. m88k running svr) needs to use
  75    different pseudo-op names for these, they may be overridden in the
  76    file which includes this one.  */
  77
  78 #undef TYPE_ASM_OP
  79 #undef SIZE_ASM_OP
  80 #define TYPE_ASM_OP     "\t.type\t"
  81 #define SIZE_ASM_OP     "\t.size\t"
  82
  83 /* If defined, a C expression whose value is a string containing the
  84    assembler operation to identify the following data as
  85    uninitialized global data.  If not defined, and neither
  86    `ASM_OUTPUT_BSS' nor `ASM_OUTPUT_ALIGNED_BSS' are defined,
  87    uninitialized global data will be output in the data section if
  88    `-fno-common' is passed, otherwise `ASM_OUTPUT_COMMON' will be
  89    used.  */
  90
  91 #ifndef BSS_SECTION_ASM_OP
  92 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
  93 #endif
  94
  95 #undef  SBSS_SECTION_ASM_OP
  96 #define SBSS_SECTION_ASM_OP     "\t.section .sbss"
  97
  98 /* Like `ASM_OUTPUT_BSS' except takes the required alignment as a
  99    separate, explicit argument.  If you define this macro, it is used
 100    in place of `ASM_OUTPUT_BSS', and gives you more flexibility in
 101    handling the required alignment of the variable.  The alignment is
 102    specified as the number of bits.
 103
 104    Try to use function `asm_output_aligned_bss' defined in file
 105    `varasm.c' when defining this macro.  */
 106 #ifndef ASM_OUTPUT_ALIGNED_BSS
 107 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 108 do {                                                                    \
 109   (*targetm.asm_out.globalize_label) (FILE, NAME);                      \
 110   if (SIZE > 0 && SIZE <= mips_section_threshold)                       \
 111     sbss_section ();                                                    \
 112   else                                                                  \
 113     bss_section ();                                                     \
 114   ASM_OUTPUT_ALIGN (FILE, floor_log2 (ALIGN / BITS_PER_UNIT));          \
 115   last_assemble_variable_decl = DECL;                                   \
 116   ASM_DECLARE_OBJECT_NAME (FILE, NAME, DECL);                           \
 117   ASM_OUTPUT_SKIP (FILE, SIZE ? SIZE : 1);                              \
 118 } while (0)
 119 #endif
 120
 121 /* These macros generate the special .type and .size directives which
 122    are used to set the corresponding fields of the linker symbol table
 123    entries in an ELF object file under SVR4.  These macros also output
 124    the starting labels for the relevant functions/objects.  */
 125
 126 /* Write the extra assembler code needed to declare an object properly.  */
 127
 128 #undef  ASM_DECLARE_OBJECT_NAME
 129 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)                       \
 130   do {                                                                  \
 131     HOST_WIDE_INT size;                                                 \
 132     ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");                   \
 133     size_directive_output = 0;                                          \
 134     if (!flag_inhibit_size_directive && DECL_SIZE (DECL))               \
 135       {                                                                 \
 136         size_directive_output = 1;                                      \
 137         size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 138         ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);                   \
 139       }                                                                 \
 140     mips_declare_object (FILE, NAME, "", ":\n", 0);                     \
 141   } while (0)
 142
 143 /* Output the size directive for a decl in rest_of_decl_compilation
 144    in the case where we did not do so before the initializer.
 145    Once we find the error_mark_node, we know that the value of
 146    size_directive_output was set
 147    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 148
 149 #undef  ASM_FINISH_DECLARE_OBJECT
 150 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 151 do {                                                                     \
 152      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 153      HOST_WIDE_INT size;                                                 \
 154                                                                          \
 155      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 156          && ! AT_END && TOP_LEVEL                                        \
 157          && DECL_INITIAL (DECL) == error_mark_node                       \
 158          && !size_directive_output)                                      \
 159        {                                                                 \
 160          size_directive_output = 1;                                      \
 161          size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 162          ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);                   \
 163        }                                                                 \
 164    } while (0)
 165
 166 #define ASM_OUTPUT_DEF(FILE,LABEL1,LABEL2)                            \
 167  do { fputc ( '\t', FILE);                                            \
 168       assemble_name (FILE, LABEL1);                                   \
 169       fputs ( " = ", FILE);                                           \
 170       assemble_name (FILE, LABEL2);                                   \
 171       fputc ( '\n', FILE);                                            \
 172  } while (0)
 173
 174 /* Note about .weak vs. .weakext
 175    The mips native assemblers support .weakext, but not .weak.
 176    mips-elf gas supports .weak, but not .weakext.
 177    mips-elf gas has been changed to support both .weak and .weakext,
 178    but until that support is generally available, the 'if' below
 179    should serve.  */
 180
 181 #undef  ASM_WEAKEN_LABEL
 182 #define ASM_WEAKEN_LABEL(FILE,NAME) ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,0)
 183 #define ASM_OUTPUT_WEAK_ALIAS(FILE,NAME,VALUE)  \
 184  do {                                           \
 185   if (TARGET_GAS)                               \
 186       fputs ("\t.weak\t", FILE);                \
 187   else                                          \
 188       fputs ("\t.weakext\t", FILE);             \
 189   assemble_name (FILE, NAME);                   \
 190   if (VALUE)                                    \
 191     {                                           \
 192       fputc (' ', FILE);                        \
 193       assemble_name (FILE, VALUE);              \
 194     }                                           \
 195   fputc ('\n', FILE);                           \
 196  } while (0)
 197
 198 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 199
 200 #define TARGET_ASM_UNIQUE_SECTION  mips_unique_section
 201
 202 /* A list of other sections which the compiler might be "in" at any
 203    given time.  */
 204 #undef  EXTRA_SECTIONS
 205 #define EXTRA_SECTIONS in_sdata, in_sbss
 206
 207 #undef  EXTRA_SECTION_FUNCTIONS
 208 #define EXTRA_SECTION_FUNCTIONS                                         \
 209   SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP) \
 210   SECTION_FUNCTION_TEMPLATE(sbss_section, in_sbss, SBSS_SECTION_ASM_OP)
 211
 212 #define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP)                               \
 213 void FN ()                                                            \
 214 {                                                                     \
 215   if (in_section != ENUM)                                             \
 216     {                                                                 \
 217       fprintf (asm_out_file, "%s\n", OP);                             \
 218       in_section = ENUM;                                              \
 219     }                                                                 \
 220 }
 221
 222 /* On elf, we *do* have support for the .init and .fini sections, and we
 223    can put stuff in there to be executed before and after `main'.  We let
 224    crtstuff.c and other files know this by defining the following symbols.
 225    The definitions say how to change sections to the .init and .fini
 226    sections.  This is the same for all known elf assemblers.  */
 227
 228 #undef  INIT_SECTION_ASM_OP
 229 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 230 #undef  FINI_SECTION_ASM_OP
 231 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 232
 233 /* Don't set the target flags, this is done by the linker script */
 234 #undef  LIB_SPEC
 235 #define LIB_SPEC ""
 236
 237 #undef  STARTFILE_SPEC
 238 #if defined(HAVE_MIPS_LIBGLOSS_STARTUP_DIRECTIVES) \
 239     || (MIPS_ABI_DEFAULT == ABI_MEABI)
 240 #define STARTFILE_SPEC "crti%O%s crtbegin%O%s"
 241 #else
 242 #define STARTFILE_SPEC "crti%O%s crtbegin%O%s %{!mno-crt0:crt0%O%s}"
 243 #endif
 244
 245 #undef  ENDFILE_SPEC
 246 #define ENDFILE_SPEC "crtend%O%s crtn%O%s"