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
   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 GNU CC.
   8
   9 GNU CC 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 GNU CC 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 GNU CC; 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 #define LINUX_DEFAULT_ELF
  25
  26 /* Output at beginning of assembler file.  */
  27 /* The .file command should always begin the output.  */
  28 #undef ASM_FILE_START
  29 #define ASM_FILE_START(FILE)                                            \
  30   do {                                                                  \
  31         output_file_directive (FILE, main_input_filename);              \
  32         if (ix86_asm_dialect == ASM_INTEL)                              \
  33           fputs ("\t.intel_syntax\n", FILE);                            \
  34   } while (0)
  35
  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 #undef DBX_REGISTER_NUMBER
  47 #define DBX_REGISTER_NUMBER(n) \
  48   (TARGET_64BIT ? dbx64_register_map[n] : svr4_dbx_register_map[n])
  49
  50 /* Output assembler code to FILE to call the profiler.
  51    To the best of my knowledge, no Linux libc has required the label
  52    argument to mcount.  */
  53
  54 #define NO_PROFILE_COUNTERS
  55
  56 #undef FUNCTION_PROFILER
  57 #define FUNCTION_PROFILER(FILE, LABELNO)  \
  58 {                                                                       \
  59   if (flag_pic)                                                         \
  60     fprintf (FILE, "\tcall\t*mcount@GOT(%%ebx)\n");                     \
  61   else                                                                  \
  62     fprintf (FILE, "\tcall\tmcount\n");                                 \
  63 }
  64
  65 /* The GLIBC version of mcount for the x86 assumes that there is a
  66    frame, so we cannot allow profiling without a frame pointer.  */
  67
  68 #undef SUBTARGET_FRAME_POINTER_REQUIRED
  69 #define SUBTARGET_FRAME_POINTER_REQUIRED current_function_profile
  70
  71 #undef SIZE_TYPE
  72 #define SIZE_TYPE "unsigned int"
  73
  74 #undef PTRDIFF_TYPE
  75 #define PTRDIFF_TYPE "int"
  76
  77 #undef WCHAR_TYPE
  78 #define WCHAR_TYPE "long int"
  79
  80 #undef WCHAR_TYPE_SIZE
  81 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  82
  83 #define TARGET_OS_CPP_BUILTINS()                \
  84   do                                            \
  85     {                                           \
  86         builtin_define_std ("linux");           \
  87         builtin_define_std ("unix");            \
  88         builtin_define ("__ELF__");             \
  89         builtin_define ("__gnu_linux__");       \
  90         builtin_assert ("system=posix");        \
  91         if (flag_pic)                           \
  92           {                                     \
  93             builtin_define ("__PIC__");         \
  94             builtin_define ("__pic__");         \
  95           }                                     \
  96     }                                           \
  97   while (0)
  98
  99 #undef CPP_SPEC
 100 #ifdef USE_GNULIBC_1
 101 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE}"
 102 #else
 103 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
 104 #endif
 105
 106 #undef CC1_SPEC
 107 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 108
 109 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 110    for the special GCC options -static and -shared, which allow us to
 111    link things in one of these three modes by applying the appropriate
 112    combinations of options at link-time. We like to support here for
 113    as many of the other GNU linker options as possible. But I don't
 114    have the time to search for those flags. I am sure how to add
 115    support for -soname shared_object_name. H.J.
 116
 117    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 118    -Wl,-V.
 119
 120    When the -shared link option is used a final link is not being
 121    done.  */
 122
 123 /* If ELF is the default format, we should not use /lib/elf.  */
 124
 125 #undef  LINK_SPEC
 126 #ifdef USE_GNULIBC_1
 127 #ifndef LINUX_DEFAULT_ELF
 128 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 129   %{!shared: \
 130     %{!ibcs: \
 131       %{!static: \
 132         %{rdynamic:-export-dynamic} \
 133         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 134         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 135 #else
 136 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 137   %{!shared: \
 138     %{!ibcs: \
 139       %{!static: \
 140         %{rdynamic:-export-dynamic} \
 141         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 142         %{static:-static}}}"
 143 #endif
 144 #else
 145 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 146   %{!shared: \
 147     %{!ibcs: \
 148       %{!static: \
 149         %{rdynamic:-export-dynamic} \
 150         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 151         %{static:-static}}}"
 152 #endif
 153
 154 /* A C statement (sans semicolon) to output to the stdio stream
 155    FILE the assembler definition of uninitialized global DECL named
 156    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 157    Try to use asm_output_aligned_bss to implement this macro.  */
 158
 159 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 160   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 161
 162 /* A C statement to output to the stdio stream FILE an assembler
 163    command to advance the location counter to a multiple of 1<<LOG
 164    bytes if it is within MAX_SKIP bytes.
 165
 166    This is used to align code labels according to Intel recommendations.  */
 167
 168 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 169 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 170   do {                                                                  \
 171     if ((LOG) != 0) {                                                   \
 172       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 173       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 174     }                                                                   \
 175   } while (0)
 176 #endif
 177
 178 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 179 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 180    __environ and atexit.  We have to make sure they are in the .dynsym
 181    section.  We do this by forcing the assembler to create undefined
 182    references to these symbols in the object file.  */
 183 #undef CRT_CALL_STATIC_FUNCTION
 184 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 185    asm (SECTION_OP "\n\t"                               \
 186         "call " USER_LABEL_PREFIX #FUNC "\n"            \
 187         TEXT_SECTION_ASM_OP "\n\t"                      \
 188         ".extern ___brk_addr\n\t"                       \
 189         ".type ___brk_addr,@object\n\t"                 \
 190         ".extern __environ\n\t"                         \
 191         ".type __environ,@object\n\t"                   \
 192         ".extern atexit\n\t"                            \
 193         ".type atexit,@function");
 194 #endif
 195
 196 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 197    indirect are handled automatically.  */
 198 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 199   do {                                                                  \
 200     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 201       {                                                                 \
 202         fputs (ASM_LONG, FILE);                 \
 203         assemble_name (FILE, XSTR (ADDR, 0));                           \
 204         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 205         goto DONE;                                                      \
 206       }                                                                 \
 207   } while (0)
 208
 209 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 210    These are GOT relative on x86, so return the pic register.  */
 211 #ifdef __PIC__
 212 #define CRT_GET_RFIB_DATA(BASE)                 \
 213   {                                             \
 214     register void *ebx_ __asm__("ebx");         \
 215     BASE = ebx_;                                \
 216   }
 217 #else
 218 #define CRT_GET_RFIB_DATA(BASE)                                         \
 219   __asm__ ("call\t.LPR%=\n"                                             \
 220            ".LPR%=:\n\t"                                                \
 221            "popl\t%0\n\t"                                               \
 222            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 223               smaller than the traditional EBX, which results in the    \
 224               offset being off by one.  */                              \
 225            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 226            : "=d"(BASE))
 227 #endif
 228
 229 /* Do code reading to identify a signal frame, and set the frame
 230    state data appropriately.  See unwind-dw2.c for the structs.  */
 231
 232 #ifdef IN_LIBGCC2
 233 #include <signal.h>
 234 #include <sys/ucontext.h>
 235 #endif
 236
 237 #define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS)               \
 238   do {                                                                  \
 239     unsigned char *pc_ = (CONTEXT)->ra;                                 \
 240     struct sigcontext *sc_;                                             \
 241     long new_cfa_;                                                      \
 242                                                                         \
 243     /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */            \
 244     if (*(unsigned short *)(pc_+0) == 0xb858                            \
 245         && *(unsigned int *)(pc_+2) == 119                              \
 246         && *(unsigned short *)(pc_+6) == 0x80cd)                        \
 247       sc_ = (CONTEXT)->cfa + 4;                                         \
 248     /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */                     \
 249     else if (*(unsigned char *)(pc_+0) == 0xb8                          \
 250              && *(unsigned int *)(pc_+1) == 173                         \
 251              && *(unsigned short *)(pc_+5) == 0x80cd)                   \
 252       {                                                                 \
 253         struct rt_sigframe {                                            \
 254           int sig;                                                      \
 255           struct siginfo *pinfo;                                        \
 256           void *puc;                                                    \
 257           struct siginfo info;                                          \
 258           struct ucontext uc;                                           \
 259         } *rt_ = (CONTEXT)->cfa;                                        \
 260         sc_ = (struct sigcontext *) &rt_->uc.uc_mcontext;               \
 261       }                                                                 \
 262     else                                                                \
 263       break;                                                            \
 264                                                                         \
 265     new_cfa_ = sc_->esp;                                                \
 266     (FS)->cfa_how = CFA_REG_OFFSET;                                     \
 267     (FS)->cfa_reg = 4;                                                  \
 268     (FS)->cfa_offset = new_cfa_ - (long) (CONTEXT)->cfa;                \
 269                                                                         \
 270     /* The SVR4 register numbering macros aren't usable in libgcc.  */  \
 271     (FS)->regs.reg[0].how = REG_SAVED_OFFSET;                           \
 272     (FS)->regs.reg[0].loc.offset = (long)&sc_->eax - new_cfa_;          \
 273     (FS)->regs.reg[3].how = REG_SAVED_OFFSET;                           \
 274     (FS)->regs.reg[3].loc.offset = (long)&sc_->ebx - new_cfa_;          \
 275     (FS)->regs.reg[1].how = REG_SAVED_OFFSET;                           \
 276     (FS)->regs.reg[1].loc.offset = (long)&sc_->ecx - new_cfa_;          \
 277     (FS)->regs.reg[2].how = REG_SAVED_OFFSET;                           \
 278     (FS)->regs.reg[2].loc.offset = (long)&sc_->edx - new_cfa_;          \
 279     (FS)->regs.reg[6].how = REG_SAVED_OFFSET;                           \
 280     (FS)->regs.reg[6].loc.offset = (long)&sc_->esi - new_cfa_;          \
 281     (FS)->regs.reg[7].how = REG_SAVED_OFFSET;                           \
 282     (FS)->regs.reg[7].loc.offset = (long)&sc_->edi - new_cfa_;          \
 283     (FS)->regs.reg[5].how = REG_SAVED_OFFSET;                           \
 284     (FS)->regs.reg[5].loc.offset = (long)&sc_->ebp - new_cfa_;          \
 285     (FS)->regs.reg[8].how = REG_SAVED_OFFSET;                           \
 286     (FS)->regs.reg[8].loc.offset = (long)&sc_->eip - new_cfa_;          \
 287     (FS)->retaddr_column = 8;                                           \
 288     goto SUCCESS;                                                       \
 289   } while (0)