gcc/config/i386/linux.h

   1 /* Definitions for Intel 386 running Linux with ELF format
   2    Copyright (C) 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
   3    Contributed by Eric Youngdale.
   4    Modified for stabs-in-ELF by H.J. Lu.
   5
   6 This file is part of GNU CC.
   7
   8 GNU CC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GNU CC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU CC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.  */
  22
  23 #define LINUX_DEFAULT_ELF
  24
  25 /* A lie, I guess, but the general idea behind linux/ELF is that we are
  26    supposed to be outputting something that will assemble under SVr4.
  27    This gets us pretty close.  */
  28 #include <i386/i386.h>  /* Base i386 target machine definitions */
  29 #include <i386/att.h>   /* Use the i386 AT&T assembler syntax */
  30 #include <linux.h>      /* some common stuff */
  31
  32 #undef TARGET_VERSION
  33 #define TARGET_VERSION fprintf (stderr, " (i386 Linux/ELF)");
  34
  35 /* The svr4 ABI for the i386 says that records and unions are returned
  36    in memory.  */
  37 #undef DEFAULT_PCC_STRUCT_RETURN
  38 #define DEFAULT_PCC_STRUCT_RETURN 1
  39
  40 /* This is how to output an element of a case-vector that is relative.
  41    This is only used for PIC code.  See comments by the `casesi' insn in
  42    i386.md for an explanation of the expression this outputs. */
  43 #undef ASM_OUTPUT_ADDR_DIFF_ELT
  44 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, VALUE, REL) \
  45   fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
  46
  47 /* Indicate that jump tables go in the text section.  This is
  48    necessary when compiling PIC code.  */
  49 #define JUMP_TABLES_IN_TEXT_SECTION
  50
  51 /* Copy this from the svr4 specifications... */
  52 /* Define the register numbers to be used in Dwarf debugging information.
  53    The SVR4 reference port C compiler uses the following register numbers
  54    in its Dwarf output code:
  55         0 for %eax (gnu regno = 0)
  56         1 for %ecx (gnu regno = 2)
  57         2 for %edx (gnu regno = 1)
  58         3 for %ebx (gnu regno = 3)
  59         4 for %esp (gnu regno = 7)
  60         5 for %ebp (gnu regno = 6)
  61         6 for %esi (gnu regno = 4)
  62         7 for %edi (gnu regno = 5)
  63    The following three DWARF register numbers are never generated by
  64    the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
  65    believes these numbers have these meanings.
  66         8  for %eip    (no gnu equivalent)
  67         9  for %eflags (no gnu equivalent)
  68         10 for %trapno (no gnu equivalent)
  69    It is not at all clear how we should number the FP stack registers
  70    for the x86 architecture.  If the version of SDB on x86/svr4 were
  71    a bit less brain dead with respect to floating-point then we would
  72    have a precedent to follow with respect to DWARF register numbers
  73    for x86 FP registers, but the SDB on x86/svr4 is so completely
  74    broken with respect to FP registers that it is hardly worth thinking
  75    of it as something to strive for compatibility with.
  76    The version of x86/svr4 SDB I have at the moment does (partially)
  77    seem to believe that DWARF register number 11 is associated with
  78    the x86 register %st(0), but that's about all.  Higher DWARF
  79    register numbers don't seem to be associated with anything in
  80    particular, and even for DWARF regno 11, SDB only seems to under-
  81    stand that it should say that a variable lives in %st(0) (when
  82    asked via an `=' command) if we said it was in DWARF regno 11,
  83    but SDB still prints garbage when asked for the value of the
  84    variable in question (via a `/' command).
  85    (Also note that the labels SDB prints for various FP stack regs
  86    when doing an `x' command are all wrong.)
  87    Note that these problems generally don't affect the native SVR4
  88    C compiler because it doesn't allow the use of -O with -g and
  89    because when it is *not* optimizing, it allocates a memory
  90    location for each floating-point variable, and the memory
  91    location is what gets described in the DWARF AT_location
  92    attribute for the variable in question.
  93    Regardless of the severe mental illness of the x86/svr4 SDB, we
  94    do something sensible here and we use the following DWARF
  95    register numbers.  Note that these are all stack-top-relative
  96    numbers.
  97         11 for %st(0) (gnu regno = 8)
  98         12 for %st(1) (gnu regno = 9)
  99         13 for %st(2) (gnu regno = 10)
 100         14 for %st(3) (gnu regno = 11)
 101         15 for %st(4) (gnu regno = 12)
 102         16 for %st(5) (gnu regno = 13)
 103         17 for %st(6) (gnu regno = 14)
 104         18 for %st(7) (gnu regno = 15)
 105 */
 106 #undef DBX_REGISTER_NUMBER
 107 #define DBX_REGISTER_NUMBER(n) \
 108 ((n) == 0 ? 0 \
 109  : (n) == 1 ? 2 \
 110  : (n) == 2 ? 1 \
 111  : (n) == 3 ? 3 \
 112  : (n) == 4 ? 6 \
 113  : (n) == 5 ? 7 \
 114  : (n) == 6 ? 5 \
 115  : (n) == 7 ? 4 \
 116  : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
 117  : (-1))
 118
 119 /* Output assembler code to FILE to increment profiler label # LABELNO
 120    for profiling a function entry.  */
 121
 122 #undef FUNCTION_PROFILER
 123 #define FUNCTION_PROFILER(FILE, LABELNO)  \
 124 {                                                                       \
 125   if (flag_pic)                                                         \
 126     {                                                                   \
 127       fprintf (FILE, "\tleal %sP%d@GOTOFF(%%ebx),%%edx\n",              \
 128                LPREFIX, (LABELNO));                                     \
 129       fprintf (FILE, "\tcall *mcount@GOT(%%ebx)\n");                    \
 130     }                                                                   \
 131   else                                                                  \
 132     {                                                                   \
 133       fprintf (FILE, "\tmovl $%sP%d,%%edx\n", LPREFIX, (LABELNO));      \
 134       fprintf (FILE, "\tcall mcount\n");                                \
 135     }                                                                   \
 136 }
 137
 138 #undef SIZE_TYPE
 139 #define SIZE_TYPE "unsigned int"
 140
 141 #undef PTRDIFF_TYPE
 142 #define PTRDIFF_TYPE "int"
 143
 144 #undef WCHAR_TYPE
 145 #define WCHAR_TYPE "long int"
 146
 147 #undef WCHAR_TYPE_SIZE
 148 #define WCHAR_TYPE_SIZE BITS_PER_WORD
 149
 150 #undef CPP_PREDEFINES
 151 #define CPP_PREDEFINES "-D__ELF__ -Dunix -Dlinux -Asystem(posix)"
 152
 153 #undef CPP_SPEC
 154 #ifdef USE_GNULIBC_1
 155 #define CPP_SPEC "%(cpp_cpu) %[cpp_cpu] %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE}"
 156 #else
 157 #define CPP_SPEC "%(cpp_cpu) %[cpp_cpu] %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
 158 #endif
 159
 160 #undef CC1_SPEC
 161 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 162
 163 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 164    for the special GCC options -static and -shared, which allow us to
 165    link things in one of these three modes by applying the appropriate
 166    combinations of options at link-time. We like to support here for
 167    as many of the other GNU linker options as possible. But I don't
 168    have the time to search for those flags. I am sure how to add
 169    support for -soname shared_object_name. H.J.
 170
 171    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 172    -Wl,-V.
 173
 174    When the -shared link option is used a final link is not being
 175    done.  */
 176
 177 /* If ELF is the default format, we should not use /lib/elf. */
 178
 179 #undef  LINK_SPEC
 180 #ifdef USE_GNULIBC_1
 181 #ifndef LINUX_DEFAULT_ELF
 182 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 183   %{!shared: \
 184     %{!ibcs: \
 185       %{!static: \
 186         %{rdynamic:-export-dynamic} \
 187         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 188         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 189 #else
 190 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 191   %{!shared: \
 192     %{!ibcs: \
 193       %{!static: \
 194         %{rdynamic:-export-dynamic} \
 195         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 196         %{static:-static}}}"
 197 #endif
 198 #else
 199 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 200   %{!shared: \
 201     %{!ibcs: \
 202       %{!static: \
 203         %{rdynamic:-export-dynamic} \
 204         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 205         %{static:-static}}}"
 206 #endif
 207
 208 /* Get perform_* macros to build libgcc.a.  */
 209 #include "i386/perform.h"
 210
 211 /* A C statement (sans semicolon) to output to the stdio stream
 212    FILE the assembler definition of uninitialized global DECL named
 213    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 214    Try to use asm_output_aligned_bss to implement this macro.  */
 215
 216 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 217   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)