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 /* We arrange for the whole %gs segment to map the tls area.  */
  44 #undef TARGET_TLS_DIRECT_SEG_REFS_DEFAULT
  45 #define TARGET_TLS_DIRECT_SEG_REFS_DEFAULT MASK_TLS_DIRECT_SEG_REFS
  46
  47 #undef ASM_COMMENT_START
  48 #define ASM_COMMENT_START "#"
  49
  50 #undef DBX_REGISTER_NUMBER
  51 #define DBX_REGISTER_NUMBER(n) \
  52   (TARGET_64BIT ? dbx64_register_map[n] : svr4_dbx_register_map[n])
  53
  54 /* Output assembler code to FILE to call the profiler.
  55    To the best of my knowledge, no Linux libc has required the label
  56    argument to mcount.  */
  57
  58 #define NO_PROFILE_COUNTERS     1
  59
  60 #undef MCOUNT_NAME
  61 #define MCOUNT_NAME "mcount"
  62
  63 /* The GLIBC version of mcount for the x86 assumes that there is a
  64    frame, so we cannot allow profiling without a frame pointer.  */
  65
  66 #undef SUBTARGET_FRAME_POINTER_REQUIRED
  67 #define SUBTARGET_FRAME_POINTER_REQUIRED current_function_profile
  68
  69 #undef SIZE_TYPE
  70 #define SIZE_TYPE "unsigned int"
  71
  72 #undef PTRDIFF_TYPE
  73 #define PTRDIFF_TYPE "int"
  74
  75 #undef WCHAR_TYPE
  76 #define WCHAR_TYPE "long int"
  77
  78 #undef WCHAR_TYPE_SIZE
  79 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  80
  81 #define TARGET_OS_CPP_BUILTINS()                \
  82   do                                            \
  83     {                                           \
  84         builtin_define_std ("linux");           \
  85         builtin_define_std ("unix");            \
  86         builtin_define ("__gnu_linux__");       \
  87         builtin_assert ("system=posix");        \
  88         if (flag_pic)                           \
  89           {                                     \
  90             builtin_define ("__PIC__");         \
  91             builtin_define ("__pic__");         \
  92           }                                     \
  93     }                                           \
  94   while (0)
  95
  96 #undef CPP_SPEC
  97 #ifdef USE_GNULIBC_1
  98 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE}"
  99 #else
 100 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
 101 #endif
 102
 103 #undef CC1_SPEC
 104 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 105
 106 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 107    for the special GCC options -static and -shared, which allow us to
 108    link things in one of these three modes by applying the appropriate
 109    combinations of options at link-time. We like to support here for
 110    as many of the other GNU linker options as possible. But I don't
 111    have the time to search for those flags. I am sure how to add
 112    support for -soname shared_object_name. H.J.
 113
 114    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 115    -Wl,-V.
 116
 117    When the -shared link option is used a final link is not being
 118    done.  */
 119
 120 /* If ELF is the default format, we should not use /lib/elf.  */
 121
 122 #undef  LINK_SPEC
 123 #ifdef USE_GNULIBC_1
 124 #ifndef LINUX_DEFAULT_ELF
 125 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 126   %{!shared: \
 127     %{!ibcs: \
 128       %{!static: \
 129         %{rdynamic:-export-dynamic} \
 130         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 131         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 132 #else
 133 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 134   %{!shared: \
 135     %{!ibcs: \
 136       %{!static: \
 137         %{rdynamic:-export-dynamic} \
 138         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 139         %{static:-static}}}"
 140 #endif
 141 #else
 142 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 143   %{!shared: \
 144     %{!ibcs: \
 145       %{!static: \
 146         %{rdynamic:-export-dynamic} \
 147         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 148         %{static:-static}}}"
 149 #endif
 150
 151 /* A C statement (sans semicolon) to output to the stdio stream
 152    FILE the assembler definition of uninitialized global DECL named
 153    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 154    Try to use asm_output_aligned_bss to implement this macro.  */
 155
 156 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 157   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 158
 159 /* A C statement to output to the stdio stream FILE an assembler
 160    command to advance the location counter to a multiple of 1<<LOG
 161    bytes if it is within MAX_SKIP bytes.
 162
 163    This is used to align code labels according to Intel recommendations.  */
 164
 165 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 166 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 167   do {                                                                  \
 168     if ((LOG) != 0) {                                                   \
 169       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 170       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 171     }                                                                   \
 172   } while (0)
 173 #endif
 174
 175 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 176 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 177    __environ and atexit.  We have to make sure they are in the .dynsym
 178    section.  We do this by forcing the assembler to create undefined
 179    references to these symbols in the object file.  */
 180 #undef CRT_CALL_STATIC_FUNCTION
 181 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 182    asm (SECTION_OP "\n\t"                               \
 183         "call " USER_LABEL_PREFIX #FUNC "\n"            \
 184         TEXT_SECTION_ASM_OP "\n\t"                      \
 185         ".extern ___brk_addr\n\t"                       \
 186         ".type ___brk_addr,@object\n\t"                 \
 187         ".extern __environ\n\t"                         \
 188         ".type __environ,@object\n\t"                   \
 189         ".extern atexit\n\t"                            \
 190         ".type atexit,@function");
 191 #endif
 192
 193 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 194    indirect are handled automatically.  */
 195 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 196   do {                                                                  \
 197     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 198       {                                                                 \
 199         fputs (ASM_LONG, FILE);                 \
 200         assemble_name (FILE, XSTR (ADDR, 0));                           \
 201         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 202         goto DONE;                                                      \
 203       }                                                                 \
 204   } while (0)
 205
 206 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 207    These are GOT relative on x86, so return the pic register.  */
 208 #ifdef __PIC__
 209 #define CRT_GET_RFIB_DATA(BASE)                 \
 210   {                                             \
 211     register void *ebx_ __asm__("ebx");         \
 212     BASE = ebx_;                                \
 213   }
 214 #else
 215 #define CRT_GET_RFIB_DATA(BASE)                                         \
 216   __asm__ ("call\t.LPR%=\n"                                             \
 217            ".LPR%=:\n\t"                                                \
 218            "popl\t%0\n\t"                                               \
 219            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 220               smaller than the traditional EBX, which results in the    \
 221               offset being off by one.  */                              \
 222            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 223            : "=d"(BASE))
 224 #endif
 225
 226 #undef NEED_INDICATE_EXEC_STACK
 227 #define NEED_INDICATE_EXEC_STACK 1
 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 /* There's no sys/ucontext.h for some (all?) libc1, so no
 234    signal-turned-exceptions for them.  There's also no configure-run for
 235    the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H.  Using the
 236    target libc1 macro should be enough.  */
 237 #ifndef USE_GNULIBC_1
 238 #include <signal.h>
 239 #include <sys/ucontext.h>
 240
 241 #define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS)               \
 242   do {                                                                  \
 243     unsigned char *pc_ = (CONTEXT)->ra;                                 \
 244     struct sigcontext *sc_;                                             \
 245     long new_cfa_;                                                      \
 246                                                                         \
 247     /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */            \
 248     if (*(unsigned short *)(pc_+0) == 0xb858                            \
 249         && *(unsigned int *)(pc_+2) == 119                              \
 250         && *(unsigned short *)(pc_+6) == 0x80cd)                        \
 251       sc_ = (CONTEXT)->cfa + 4;                                         \
 252     /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */                     \
 253     else if (*(unsigned char *)(pc_+0) == 0xb8                          \
 254              && *(unsigned int *)(pc_+1) == 173                         \
 255              && *(unsigned short *)(pc_+5) == 0x80cd)                   \
 256       {                                                                 \
 257         struct rt_sigframe {                                            \
 258           int sig;                                                      \
 259           struct siginfo *pinfo;                                        \
 260           void *puc;                                                    \
 261           struct siginfo info;                                          \
 262           struct ucontext uc;                                           \
 263         } *rt_ = (CONTEXT)->cfa;                                        \
 264         sc_ = (struct sigcontext *) &rt_->uc.uc_mcontext;               \
 265       }                                                                 \
 266     else                                                                \
 267       break;                                                            \
 268                                                                         \
 269     new_cfa_ = sc_->esp;                                                \
 270     (FS)->cfa_how = CFA_REG_OFFSET;                                     \
 271     (FS)->cfa_reg = 4;                                                  \
 272     (FS)->cfa_offset = new_cfa_ - (long) (CONTEXT)->cfa;                \
 273                                                                         \
 274     /* The SVR4 register numbering macros aren't usable in libgcc.  */  \
 275     (FS)->regs.reg[0].how = REG_SAVED_OFFSET;                           \
 276     (FS)->regs.reg[0].loc.offset = (long)&sc_->eax - new_cfa_;          \
 277     (FS)->regs.reg[3].how = REG_SAVED_OFFSET;                           \
 278     (FS)->regs.reg[3].loc.offset = (long)&sc_->ebx - new_cfa_;          \
 279     (FS)->regs.reg[1].how = REG_SAVED_OFFSET;                           \
 280     (FS)->regs.reg[1].loc.offset = (long)&sc_->ecx - new_cfa_;          \
 281     (FS)->regs.reg[2].how = REG_SAVED_OFFSET;                           \
 282     (FS)->regs.reg[2].loc.offset = (long)&sc_->edx - new_cfa_;          \
 283     (FS)->regs.reg[6].how = REG_SAVED_OFFSET;                           \
 284     (FS)->regs.reg[6].loc.offset = (long)&sc_->esi - new_cfa_;          \
 285     (FS)->regs.reg[7].how = REG_SAVED_OFFSET;                           \
 286     (FS)->regs.reg[7].loc.offset = (long)&sc_->edi - new_cfa_;          \
 287     (FS)->regs.reg[5].how = REG_SAVED_OFFSET;                           \
 288     (FS)->regs.reg[5].loc.offset = (long)&sc_->ebp - new_cfa_;          \
 289     (FS)->regs.reg[8].how = REG_SAVED_OFFSET;                           \
 290     (FS)->regs.reg[8].loc.offset = (long)&sc_->eip - new_cfa_;          \
 291     (FS)->retaddr_column = 8;                                           \
 292     goto SUCCESS;                                                       \
 293   } while (0)
 294 #endif /* not USE_GNULIBC_1 */
 295 #endif /* IN_LIBGCC2 */