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 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 /* Output at beginning of assembler file.  */
  26 /* The .file command should always begin the output.  */
  27 #undef ASM_FILE_START
  28 #define ASM_FILE_START(FILE)                                            \
  29   do {                                                                  \
  30         output_file_directive (FILE, main_input_filename);              \
  31         if (target_flags & MASK_INTEL_SYNTAX)                           \
  32           fputs ("\t.intel_syntax\n", FILE);                            \
  33   } while (0)
  34
  35 #undef TARGET_VERSION
  36 #define TARGET_VERSION fprintf (stderr, " (i386 Linux/ELF)");
  37
  38 /* The svr4 ABI for the i386 says that records and unions are returned
  39    in memory.  */
  40 #undef DEFAULT_PCC_STRUCT_RETURN
  41 #define DEFAULT_PCC_STRUCT_RETURN 1
  42
  43 #undef ASM_COMMENT_START
  44 #define ASM_COMMENT_START "#"
  45
  46 /* This is how to output an element of a case-vector that is relative.
  47    This is only used for PIC code.  See comments by the `casesi' insn in
  48    i386.md for an explanation of the expression this outputs. */
  49 #undef ASM_OUTPUT_ADDR_DIFF_ELT
  50 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, BODY, VALUE, REL) \
  51   fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
  52
  53 /* Indicate that jump tables go in the text section.  This is
  54    necessary when compiling PIC code.  */
  55 #define JUMP_TABLES_IN_TEXT_SECTION (flag_pic)
  56
  57 #undef DBX_REGISTER_NUMBER
  58 #define DBX_REGISTER_NUMBER(n) \
  59   (TARGET_64BIT ? dbx64_register_map[n] : svr4_dbx_register_map[n])
  60
  61 /* Output assembler code to FILE to call the profiler.
  62    To the best of my knowledge, no Linux libc has required the label
  63    argument to mcount.  */
  64
  65 #define NO_PROFILE_COUNTERS
  66
  67 #undef FUNCTION_PROFILER
  68 #define FUNCTION_PROFILER(FILE, LABELNO)  \
  69 {                                                                       \
  70   if (flag_pic)                                                         \
  71     fprintf (FILE, "\tcall\t*mcount@GOT(%%ebx)\n");                     \
  72   else                                                                  \
  73     fprintf (FILE, "\tcall\tmcount\n");                                 \
  74 }
  75
  76 /* True if it is possible to profile code that does not have a frame
  77    pointer.
  78
  79    The GLIBC version of mcount for the x86 assumes that there is a
  80    frame, so we cannot allow profiling without a frame pointer.  */
  81
  82 #undef TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
  83 #define TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER false
  84
  85 #undef SIZE_TYPE
  86 #define SIZE_TYPE "unsigned int"
  87
  88 #undef PTRDIFF_TYPE
  89 #define PTRDIFF_TYPE "int"
  90
  91 #undef WCHAR_TYPE
  92 #define WCHAR_TYPE "long int"
  93
  94 #undef WCHAR_TYPE_SIZE
  95 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  96
  97 #undef CPP_PREDEFINES
  98 #define CPP_PREDEFINES "-D__ELF__ -Dunix -Dlinux -Asystem=posix"
  99
 100 #undef CPP_SPEC
 101 #ifdef USE_GNULIBC_1
 102 #define CPP_SPEC "%(cpp_cpu) %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE}"
 103 #else
 104 #define CPP_SPEC "%(cpp_cpu) %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
 105 #endif
 106
 107 #undef CC1_SPEC
 108 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 109
 110 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 111    for the special GCC options -static and -shared, which allow us to
 112    link things in one of these three modes by applying the appropriate
 113    combinations of options at link-time. We like to support here for
 114    as many of the other GNU linker options as possible. But I don't
 115    have the time to search for those flags. I am sure how to add
 116    support for -soname shared_object_name. H.J.
 117
 118    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 119    -Wl,-V.
 120
 121    When the -shared link option is used a final link is not being
 122    done.  */
 123
 124 /* If ELF is the default format, we should not use /lib/elf. */
 125
 126 #undef  LINK_SPEC
 127 #ifdef USE_GNULIBC_1
 128 #ifndef LINUX_DEFAULT_ELF
 129 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 130   %{!shared: \
 131     %{!ibcs: \
 132       %{!static: \
 133         %{rdynamic:-export-dynamic} \
 134         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 135         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 136 #else
 137 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 138   %{!shared: \
 139     %{!ibcs: \
 140       %{!static: \
 141         %{rdynamic:-export-dynamic} \
 142         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 143         %{static:-static}}}"
 144 #endif
 145 #else
 146 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 147   %{!shared: \
 148     %{!ibcs: \
 149       %{!static: \
 150         %{rdynamic:-export-dynamic} \
 151         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 152         %{static:-static}}}"
 153 #endif
 154
 155 /* A C statement (sans semicolon) to output to the stdio stream
 156    FILE the assembler definition of uninitialized global DECL named
 157    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 158    Try to use asm_output_aligned_bss to implement this macro.  */
 159
 160 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 161   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 162
 163 /* A C statement to output to the stdio stream FILE an assembler
 164    command to advance the location counter to a multiple of 1<<LOG
 165    bytes if it is within MAX_SKIP bytes.
 166
 167    This is used to align code labels according to Intel recommendations.  */
 168
 169 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 170 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 171   do {                                                                  \
 172     if ((LOG) != 0) {                                                   \
 173       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 174       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 175     }                                                                   \
 176   } while (0)
 177 #endif
 178
 179 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 180 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 181    __environ and atexit (). We have to make sure they are in the .dynsym
 182    section. We accomplish it by making a dummy call here. This
 183    code is never reached.  */
 184
 185 #define CRT_END_INIT_DUMMY              \
 186   do                                    \
 187     {                                   \
 188       extern void *___brk_addr;         \
 189       extern char **__environ;          \
 190                                         \
 191       ___brk_addr = __environ;          \
 192       atexit (0);                       \
 193     }                                   \
 194   while (0)
 195 #endif
 196
 197 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 198    indirect are handled automatically.  */
 199 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 200   do {                                                                  \
 201     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 202       {                                                                 \
 203         fputs (UNALIGNED_INT_ASM_OP, FILE);                             \
 204         assemble_name (FILE, XSTR (ADDR, 0));                           \
 205         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 206         goto DONE;                                                      \
 207       }                                                                 \
 208   } while (0)
 209
 210 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 211    These are GOT relative on x86, so return the pic register.  */
 212 #ifdef __PIC__
 213 #define CRT_GET_RFIB_DATA(BASE)                 \
 214   {                                             \
 215     register void *ebx_ __asm__("ebx");         \
 216     BASE = ebx_;                                \
 217   }
 218 #else
 219 #define CRT_GET_RFIB_DATA(BASE)                                         \
 220   __asm__ ("call\t.LPR%=\n"                                             \
 221            ".LPR%=:\n\t"                                                \
 222            "popl\t%0\n\t"                                               \
 223            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 224               smaller than the traditional EBX, which results in the    \
 225               offset being off by one.  */                              \
 226            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 227            : "=d"(BASE))
 228 #endif
 229
 230 /* Do code reading to identify a signal frame, and set the frame
 231    state data appropriately.  See unwind-dw2.c for the structs.  */
 232
 233 #ifdef IN_LIBGCC2
 234 #include <signal.h>
 235 #include <sys/ucontext.h>
 236 #endif
 237
 238 #define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS)               \
 239   do {                                                                  \
 240     unsigned char *pc_ = (CONTEXT)->ra;                                 \
 241     struct sigcontext *sc_;                                             \
 242     long new_cfa_;                                                      \
 243                                                                         \
 244     /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */            \
 245     if (*(unsigned short *)(pc_+0) == 0xb858                            \
 246         && *(unsigned int *)(pc_+2) == 119                              \
 247         && *(unsigned short *)(pc_+6) == 0x80cd)                        \
 248       sc_ = (CONTEXT)->cfa + 4;                                         \
 249     /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */                     \
 250     else if (*(unsigned char *)(pc_+0) == 0xb8                          \
 251              && *(unsigned int *)(pc_+1) == 173                         \
 252              && *(unsigned short *)(pc_+5) == 0x80cd)                   \
 253       {                                                                 \
 254         struct rt_sigframe {                                            \
 255           int sig;                                                      \
 256           struct siginfo *pinfo;                                        \
 257           void *puc;                                                    \
 258           struct siginfo info;                                          \
 259           struct ucontext uc;                                           \
 260         } *rt_ = (CONTEXT)->cfa;                                        \
 261         sc_ = (struct sigcontext *) &rt_->uc.uc_mcontext;               \
 262       }                                                                 \
 263     else                                                                \
 264       break;                                                            \
 265                                                                         \
 266     new_cfa_ = sc_->esp;                                                \
 267     (FS)->cfa_how = CFA_REG_OFFSET;                                     \
 268     (FS)->cfa_reg = 4;                                                  \
 269     (FS)->cfa_offset = new_cfa_ - (long) (CONTEXT)->cfa;                \
 270                                                                         \
 271     /* The SVR4 register numbering macros aren't usable in libgcc.  */  \
 272     (FS)->regs.reg[0].how = REG_SAVED_OFFSET;                           \
 273     (FS)->regs.reg[0].loc.offset = (long)&sc_->eax - new_cfa_;          \
 274     (FS)->regs.reg[3].how = REG_SAVED_OFFSET;                           \
 275     (FS)->regs.reg[3].loc.offset = (long)&sc_->ebx - new_cfa_;          \
 276     (FS)->regs.reg[1].how = REG_SAVED_OFFSET;                           \
 277     (FS)->regs.reg[1].loc.offset = (long)&sc_->ecx - new_cfa_;          \
 278     (FS)->regs.reg[2].how = REG_SAVED_OFFSET;                           \
 279     (FS)->regs.reg[2].loc.offset = (long)&sc_->edx - new_cfa_;          \
 280     (FS)->regs.reg[6].how = REG_SAVED_OFFSET;                           \
 281     (FS)->regs.reg[6].loc.offset = (long)&sc_->esi - new_cfa_;          \
 282     (FS)->regs.reg[7].how = REG_SAVED_OFFSET;                           \
 283     (FS)->regs.reg[7].loc.offset = (long)&sc_->edi - new_cfa_;          \
 284     (FS)->regs.reg[5].how = REG_SAVED_OFFSET;                           \
 285     (FS)->regs.reg[5].loc.offset = (long)&sc_->ebp - new_cfa_;          \
 286     (FS)->regs.reg[8].how = REG_SAVED_OFFSET;                           \
 287     (FS)->regs.reg[8].loc.offset = (long)&sc_->eip - new_cfa_;          \
 288     (FS)->retaddr_column = 8;                                           \
 289     goto SUCCESS;                                                       \
 290   } while (0)