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     1
  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 ("__gnu_linux__");       \
  83         builtin_assert ("system=posix");        \
  84         if (flag_pic)                           \
  85           {                                     \
  86             builtin_define ("__PIC__");         \
  87             builtin_define ("__pic__");         \
  88           }                                     \
  89     }                                           \
  90   while (0)
  91
  92 #undef CPP_SPEC
  93 #ifdef USE_GNULIBC_1
  94 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE}"
  95 #else
  96 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
  97 #endif
  98
  99 #undef CC1_SPEC
 100 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
 101
 102 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 103    for the special GCC options -static and -shared, which allow us to
 104    link things in one of these three modes by applying the appropriate
 105    combinations of options at link-time. We like to support here for
 106    as many of the other GNU linker options as possible. But I don't
 107    have the time to search for those flags. I am sure how to add
 108    support for -soname shared_object_name. H.J.
 109
 110    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 111    -Wl,-V.
 112
 113    When the -shared link option is used a final link is not being
 114    done.  */
 115
 116 /* If ELF is the default format, we should not use /lib/elf.  */
 117
 118 #undef  LINK_SPEC
 119 #ifdef USE_GNULIBC_1
 120 #ifndef LINUX_DEFAULT_ELF
 121 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 122   %{!shared: \
 123     %{!ibcs: \
 124       %{!static: \
 125         %{rdynamic:-export-dynamic} \
 126         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 127         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 128 #else
 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/ld-linux.so.1}} \
 135         %{static:-static}}}"
 136 #endif
 137 #else
 138 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 139   %{!shared: \
 140     %{!ibcs: \
 141       %{!static: \
 142         %{rdynamic:-export-dynamic} \
 143         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 144         %{static:-static}}}"
 145 #endif
 146
 147 /* A C statement (sans semicolon) to output to the stdio stream
 148    FILE the assembler definition of uninitialized global DECL named
 149    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 150    Try to use asm_output_aligned_bss to implement this macro.  */
 151
 152 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 153   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 154
 155 /* A C statement to output to the stdio stream FILE an assembler
 156    command to advance the location counter to a multiple of 1<<LOG
 157    bytes if it is within MAX_SKIP bytes.
 158
 159    This is used to align code labels according to Intel recommendations.  */
 160
 161 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 162 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 163   do {                                                                  \
 164     if ((LOG) != 0) {                                                   \
 165       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 166       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 167     }                                                                   \
 168   } while (0)
 169 #endif
 170
 171 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 172 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 173    __environ and atexit.  We have to make sure they are in the .dynsym
 174    section.  We do this by forcing the assembler to create undefined
 175    references to these symbols in the object file.  */
 176 #undef CRT_CALL_STATIC_FUNCTION
 177 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 178    asm (SECTION_OP "\n\t"                               \
 179         "call " USER_LABEL_PREFIX #FUNC "\n"            \
 180         TEXT_SECTION_ASM_OP "\n\t"                      \
 181         ".extern ___brk_addr\n\t"                       \
 182         ".type ___brk_addr,@object\n\t"                 \
 183         ".extern __environ\n\t"                         \
 184         ".type __environ,@object\n\t"                   \
 185         ".extern atexit\n\t"                            \
 186         ".type atexit,@function");
 187 #endif
 188
 189 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 190    indirect are handled automatically.  */
 191 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 192   do {                                                                  \
 193     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 194       {                                                                 \
 195         fputs (ASM_LONG, FILE);                 \
 196         assemble_name (FILE, XSTR (ADDR, 0));                           \
 197         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 198         goto DONE;                                                      \
 199       }                                                                 \
 200   } while (0)
 201
 202 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 203    These are GOT relative on x86, so return the pic register.  */
 204 #ifdef __PIC__
 205 #define CRT_GET_RFIB_DATA(BASE)                 \
 206   {                                             \
 207     register void *ebx_ __asm__("ebx");         \
 208     BASE = ebx_;                                \
 209   }
 210 #else
 211 #define CRT_GET_RFIB_DATA(BASE)                                         \
 212   __asm__ ("call\t.LPR%=\n"                                             \
 213            ".LPR%=:\n\t"                                                \
 214            "popl\t%0\n\t"                                               \
 215            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 216               smaller than the traditional EBX, which results in the    \
 217               offset being off by one.  */                              \
 218            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 219            : "=d"(BASE))
 220 #endif
 221
 222 #define SUBTARGET_FILE_END(FILE) \
 223   do {                                                                  \
 224     named_section_flags (".note.GNU-stack",                             \
 225                          SECTION_DEBUG                                  \
 226                          | (trampolines_created ? SECTION_CODE : 0));   \
 227   } while (0)
 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 */