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 MCOUNT_NAME
  57 #define MCOUNT_NAME "mcount"
  58
  59 /* The GLIBC version of mcount for the x86 assumes that there is a
  60    frame, so we cannot allow profiling without a frame pointer.  */
  61
  62 #undef SUBTARGET_FRAME_POINTER_REQUIRED
  63 #define SUBTARGET_FRAME_POINTER_REQUIRED current_function_profile
  64
  65 #undef SIZE_TYPE
  66 #define SIZE_TYPE "unsigned int"
  67
  68 #undef PTRDIFF_TYPE
  69 #define PTRDIFF_TYPE "int"
  70
  71 #undef WCHAR_TYPE
  72 #define WCHAR_TYPE "long int"
  73
  74 #undef WCHAR_TYPE_SIZE
  75 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  76
  77 #define TARGET_OS_CPP_BUILTINS()                \
  78   do                                            \
  79     {                                           \
  80         builtin_define_std ("linux");           \
  81         builtin_define_std ("unix");            \
  82         builtin_define ("__ELF__");             \
  83         builtin_define ("__gnu_linux__");       \
  84         builtin_assert ("system=posix");        \
  85         if (flag_pic)                           \
  86           {                                     \
  87             builtin_define ("__PIC__");         \
  88             builtin_define ("__pic__");         \
  89           }                                     \
  90     }                                           \
  91   while (0)
  92
  93 #undef CPP_SPEC
  94 #ifdef USE_GNULIBC_1
  95 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE}"
  96 #else
  97 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
  98 #endif
  99
 100 #undef CC1_SPEC
 101 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 102
 103 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 104    for the special GCC options -static and -shared, which allow us to
 105    link things in one of these three modes by applying the appropriate
 106    combinations of options at link-time. We like to support here for
 107    as many of the other GNU linker options as possible. But I don't
 108    have the time to search for those flags. I am sure how to add
 109    support for -soname shared_object_name. H.J.
 110
 111    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 112    -Wl,-V.
 113
 114    When the -shared link option is used a final link is not being
 115    done.  */
 116
 117 /* If ELF is the default format, we should not use /lib/elf.  */
 118
 119 #undef  LINK_SPEC
 120 #ifdef USE_GNULIBC_1
 121 #ifndef LINUX_DEFAULT_ELF
 122 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 123   %{!shared: \
 124     %{!ibcs: \
 125       %{!static: \
 126         %{rdynamic:-export-dynamic} \
 127         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 128         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 129 #else
 130 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 131   %{!shared: \
 132     %{!ibcs: \
 133       %{!static: \
 134         %{rdynamic:-export-dynamic} \
 135         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 136         %{static:-static}}}"
 137 #endif
 138 #else
 139 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 140   %{!shared: \
 141     %{!ibcs: \
 142       %{!static: \
 143         %{rdynamic:-export-dynamic} \
 144         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 145         %{static:-static}}}"
 146 #endif
 147
 148 /* A C statement (sans semicolon) to output to the stdio stream
 149    FILE the assembler definition of uninitialized global DECL named
 150    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 151    Try to use asm_output_aligned_bss to implement this macro.  */
 152
 153 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 154   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 155
 156 /* A C statement to output to the stdio stream FILE an assembler
 157    command to advance the location counter to a multiple of 1<<LOG
 158    bytes if it is within MAX_SKIP bytes.
 159
 160    This is used to align code labels according to Intel recommendations.  */
 161
 162 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 163 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 164   do {                                                                  \
 165     if ((LOG) != 0) {                                                   \
 166       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 167       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 168     }                                                                   \
 169   } while (0)
 170 #endif
 171
 172 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 173 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 174    __environ and atexit.  We have to make sure they are in the .dynsym
 175    section.  We do this by forcing the assembler to create undefined
 176    references to these symbols in the object file.  */
 177 #undef CRT_CALL_STATIC_FUNCTION
 178 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 179    asm (SECTION_OP "\n\t"                               \
 180         "call " USER_LABEL_PREFIX #FUNC "\n"            \
 181         TEXT_SECTION_ASM_OP "\n\t"                      \
 182         ".extern ___brk_addr\n\t"                       \
 183         ".type ___brk_addr,@object\n\t"                 \
 184         ".extern __environ\n\t"                         \
 185         ".type __environ,@object\n\t"                   \
 186         ".extern atexit\n\t"                            \
 187         ".type atexit,@function");
 188 #endif
 189
 190 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 191    indirect are handled automatically.  */
 192 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 193   do {                                                                  \
 194     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 195       {                                                                 \
 196         fputs (ASM_LONG, FILE);                 \
 197         assemble_name (FILE, XSTR (ADDR, 0));                           \
 198         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 199         goto DONE;                                                      \
 200       }                                                                 \
 201   } while (0)
 202
 203 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 204    These are GOT relative on x86, so return the pic register.  */
 205 #ifdef __PIC__
 206 #define CRT_GET_RFIB_DATA(BASE)                 \
 207   {                                             \
 208     register void *ebx_ __asm__("ebx");         \
 209     BASE = ebx_;                                \
 210   }
 211 #else
 212 #define CRT_GET_RFIB_DATA(BASE)                                         \
 213   __asm__ ("call\t.LPR%=\n"                                             \
 214            ".LPR%=:\n\t"                                                \
 215            "popl\t%0\n\t"                                               \
 216            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 217               smaller than the traditional EBX, which results in the    \
 218               offset being off by one.  */                              \
 219            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 220            : "=d"(BASE))
 221 #endif
 222
 223 /* Do code reading to identify a signal frame, and set the frame
 224    state data appropriately.  See unwind-dw2.c for the structs.  */
 225
 226 #ifdef IN_LIBGCC2
 227 /* There's no sys/ucontext.h for some (all?) libc1, so no
 228    signal-turned-exceptions for them.  There's also no configure-run for
 229    the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H.  Using the
 230    target libc1 macro should be enough.  */
 231 #ifndef USE_GNULIBC_1
 232 #include <signal.h>
 233 #include <sys/ucontext.h>
 234
 235 #define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS)               \
 236   do {                                                                  \
 237     unsigned char *pc_ = (CONTEXT)->ra;                                 \
 238     struct sigcontext *sc_;                                             \
 239     long new_cfa_;                                                      \
 240                                                                         \
 241     /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */            \
 242     if (*(unsigned short *)(pc_+0) == 0xb858                            \
 243         && *(unsigned int *)(pc_+2) == 119                              \
 244         && *(unsigned short *)(pc_+6) == 0x80cd)                        \
 245       sc_ = (CONTEXT)->cfa + 4;                                         \
 246     /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */                     \
 247     else if (*(unsigned char *)(pc_+0) == 0xb8                          \
 248              && *(unsigned int *)(pc_+1) == 173                         \
 249              && *(unsigned short *)(pc_+5) == 0x80cd)                   \
 250       {                                                                 \
 251         struct rt_sigframe {                                            \
 252           int sig;                                                      \
 253           struct siginfo *pinfo;                                        \
 254           void *puc;                                                    \
 255           struct siginfo info;                                          \
 256           struct ucontext uc;                                           \
 257         } *rt_ = (CONTEXT)->cfa;                                        \
 258         sc_ = (struct sigcontext *) &rt_->uc.uc_mcontext;               \
 259       }                                                                 \
 260     else                                                                \
 261       break;                                                            \
 262                                                                         \
 263     new_cfa_ = sc_->esp;                                                \
 264     (FS)->cfa_how = CFA_REG_OFFSET;                                     \
 265     (FS)->cfa_reg = 4;                                                  \
 266     (FS)->cfa_offset = new_cfa_ - (long) (CONTEXT)->cfa;                \
 267                                                                         \
 268     /* The SVR4 register numbering macros aren't usable in libgcc.  */  \
 269     (FS)->regs.reg[0].how = REG_SAVED_OFFSET;                           \
 270     (FS)->regs.reg[0].loc.offset = (long)&sc_->eax - new_cfa_;          \
 271     (FS)->regs.reg[3].how = REG_SAVED_OFFSET;                           \
 272     (FS)->regs.reg[3].loc.offset = (long)&sc_->ebx - new_cfa_;          \
 273     (FS)->regs.reg[1].how = REG_SAVED_OFFSET;                           \
 274     (FS)->regs.reg[1].loc.offset = (long)&sc_->ecx - new_cfa_;          \
 275     (FS)->regs.reg[2].how = REG_SAVED_OFFSET;                           \
 276     (FS)->regs.reg[2].loc.offset = (long)&sc_->edx - new_cfa_;          \
 277     (FS)->regs.reg[6].how = REG_SAVED_OFFSET;                           \
 278     (FS)->regs.reg[6].loc.offset = (long)&sc_->esi - new_cfa_;          \
 279     (FS)->regs.reg[7].how = REG_SAVED_OFFSET;                           \
 280     (FS)->regs.reg[7].loc.offset = (long)&sc_->edi - new_cfa_;          \
 281     (FS)->regs.reg[5].how = REG_SAVED_OFFSET;                           \
 282     (FS)->regs.reg[5].loc.offset = (long)&sc_->ebp - new_cfa_;          \
 283     (FS)->regs.reg[8].how = REG_SAVED_OFFSET;                           \
 284     (FS)->regs.reg[8].loc.offset = (long)&sc_->eip - new_cfa_;          \
 285     (FS)->retaddr_column = 8;                                           \
 286     goto SUCCESS;                                                       \
 287   } while (0)
 288 #endif /* not USE_GNULIBC_1 */
 289 #endif /* IN_LIBGCC2 */