gcc/config/i386/linux.h

   1 /* Definitions for Intel 386 running Linux-based GNU systems with ELF format.
   2    Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, 2004
   3    Free Software Foundation, Inc.
   4    Contributed by Eric Youngdale.
   5    Modified for stabs-in-ELF by H.J. Lu.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 2, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING.  If not, write to
  21 the Free Software Foundation, 59 Temple Place - Suite 330,
  22 Boston, MA 02111-1307, USA.  */
  23
  24 /* Output at beginning of assembler file.  */
  25 /* The .file command should always begin the output.  */
  26 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
  27
  28 #define TARGET_VERSION fprintf (stderr, " (i386 Linux/ELF)");
  29
  30 /* The svr4 ABI for the i386 says that records and unions are returned
  31    in memory.  */
  32 #undef DEFAULT_PCC_STRUCT_RETURN
  33 #define DEFAULT_PCC_STRUCT_RETURN 1
  34
  35 /* We arrange for the whole %gs segment to map the tls area.  */
  36 #undef TARGET_TLS_DIRECT_SEG_REFS_DEFAULT
  37 #define TARGET_TLS_DIRECT_SEG_REFS_DEFAULT MASK_TLS_DIRECT_SEG_REFS
  38
  39 #undef ASM_COMMENT_START
  40 #define ASM_COMMENT_START "#"
  41
  42 #undef DBX_REGISTER_NUMBER
  43 #define DBX_REGISTER_NUMBER(n) \
  44   (TARGET_64BIT ? dbx64_register_map[n] : svr4_dbx_register_map[n])
  45
  46 /* Output assembler code to FILE to call the profiler.
  47    To the best of my knowledge, no Linux libc has required the label
  48    argument to mcount.  */
  49
  50 #define NO_PROFILE_COUNTERS     1
  51
  52 #undef MCOUNT_NAME
  53 #define MCOUNT_NAME "mcount"
  54
  55 /* The GLIBC version of mcount for the x86 assumes that there is a
  56    frame, so we cannot allow profiling without a frame pointer.  */
  57
  58 #undef SUBTARGET_FRAME_POINTER_REQUIRED
  59 #define SUBTARGET_FRAME_POINTER_REQUIRED current_function_profile
  60
  61 #undef SIZE_TYPE
  62 #define SIZE_TYPE "unsigned int"
  63
  64 #undef PTRDIFF_TYPE
  65 #define PTRDIFF_TYPE "int"
  66
  67 #undef WCHAR_TYPE
  68 #define WCHAR_TYPE "long int"
  69
  70 #undef WCHAR_TYPE_SIZE
  71 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  72
  73 #define TARGET_OS_CPP_BUILTINS()                \
  74   do                                            \
  75     {                                           \
  76         LINUX_TARGET_OS_CPP_BUILTINS();         \
  77         if (flag_pic)                           \
  78           {                                     \
  79             builtin_define ("__PIC__");         \
  80             builtin_define ("__pic__");         \
  81           }                                     \
  82     }                                           \
  83   while (0)
  84
  85 #undef CPP_SPEC
  86 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
  87
  88 #undef CC1_SPEC
  89 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
  90
  91 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
  92    for the special GCC options -static and -shared, which allow us to
  93    link things in one of these three modes by applying the appropriate
  94    combinations of options at link-time. We like to support here for
  95    as many of the other GNU linker options as possible. But I don't
  96    have the time to search for those flags. I am sure how to add
  97    support for -soname shared_object_name. H.J.
  98
  99    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 100    -Wl,-V.
 101
 102    When the -shared link option is used a final link is not being
 103    done.  */
 104
 105 /* If ELF is the default format, we should not use /lib/elf.  */
 106
 107 #define LINK_EMULATION "elf_i386"
 108 #define DYNAMIC_LINKER "/lib/ld-linux.so.2"
 109
 110 #undef  SUBTARGET_EXTRA_SPECS
 111 #define SUBTARGET_EXTRA_SPECS \
 112   { "link_emulation", LINK_EMULATION },\
 113   { "dynamic_linker", DYNAMIC_LINKER }
 114
 115 #undef  LINK_SPEC
 116 #define LINK_SPEC "-m %(link_emulation) %{shared:-shared} \
 117   %{!shared: \
 118     %{!ibcs: \
 119       %{!static: \
 120         %{rdynamic:-export-dynamic} \
 121         %{!dynamic-linker:-dynamic-linker %(dynamic_linker)}} \
 122         %{static:-static}}}"
 123
 124 /* A C statement (sans semicolon) to output to the stdio stream
 125    FILE the assembler definition of uninitialized global DECL named
 126    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 127    Try to use asm_output_aligned_bss to implement this macro.  */
 128
 129 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 130   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 131
 132 /* A C statement to output to the stdio stream FILE an assembler
 133    command to advance the location counter to a multiple of 1<<LOG
 134    bytes if it is within MAX_SKIP bytes.
 135
 136    This is used to align code labels according to Intel recommendations.  */
 137
 138 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 139 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 140   do {                                                                  \
 141     if ((LOG) != 0) {                                                   \
 142       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 143       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 144     }                                                                   \
 145   } while (0)
 146 #endif
 147
 148 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 149    indirect are handled automatically.  */
 150 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 151   do {                                                                  \
 152     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 153       {                                                                 \
 154         fputs (ASM_LONG, FILE);                 \
 155         assemble_name (FILE, XSTR (ADDR, 0));                           \
 156         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 157         goto DONE;                                                      \
 158       }                                                                 \
 159   } while (0)
 160
 161 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 162    These are GOT relative on x86, so return the pic register.  */
 163 #ifdef __PIC__
 164 #define CRT_GET_RFIB_DATA(BASE)                 \
 165   {                                             \
 166     register void *ebx_ __asm__("ebx");         \
 167     BASE = ebx_;                                \
 168   }
 169 #else
 170 #define CRT_GET_RFIB_DATA(BASE)                                         \
 171   __asm__ ("call\t.LPR%=\n"                                             \
 172            ".LPR%=:\n\t"                                                \
 173            "popl\t%0\n\t"                                               \
 174            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 175               smaller than the traditional EBX, which results in the    \
 176               offset being off by one.  */                              \
 177            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 178            : "=d"(BASE))
 179 #endif
 180
 181 #undef NEED_INDICATE_EXEC_STACK
 182 #define NEED_INDICATE_EXEC_STACK 1
 183
 184 #define MD_UNWIND_SUPPORT "config/i386/linux-unwind.h"
 185
 186 /* This macro may be overridden in i386/k*bsd-gnu.h.  */
 187 #define REG_NAME(reg) reg