sysdeps/i386/sysdep.h

   1 /* Assembler macros for i386.
   2    Copyright (C) 1991-93,95,96,98,2002,2003,2005,2006,2011,2012
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <sysdeps/generic/sysdep.h>
  22
  23 #ifdef __ASSEMBLER__
  24 # define GET_PC_THUNK(reg) __i686.get_pc_thunk.reg
  25 #else
  26 # define GET_PC_THUNK_STR(reg) "__i686.get_pc_thunk." #reg
  27 #endif
  28
  29 #ifdef  __ASSEMBLER__
  30
  31 /* Syntactic details of assembler.  */
  32
  33 /* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
  34 #define ALIGNARG(log2) 1<<log2
  35 /* For ELF we need the `.type' directive to make shared libs work right.  */
  36 #define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
  37 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
  38
  39
  40 /* Define an entry point visible from C.
  41
  42    There is currently a bug in gdb which prevents us from specifying
  43    incomplete stabs information.  Fake some entries here which specify
  44    the current source file.  */
  45 #define ENTRY(name)                                                           \
  46   STABS_CURRENT_FILE1("")                                                     \
  47   STABS_CURRENT_FILE(name)                                                    \
  48   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);                                   \
  49   ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)                          \
  50   .align ALIGNARG(4);                                                         \
  51   STABS_FUN(name)                                                             \
  52   C_LABEL(name)                                                               \
  53   cfi_startproc;                                                              \
  54   CALL_MCOUNT
  55
  56 #undef  END
  57 #define END(name)                                                             \
  58   cfi_endproc;                                                                \
  59   ASM_SIZE_DIRECTIVE(name)                                                    \
  60   STABS_FUN_END(name)
  61
  62 #define ENTRY_CHK(name) ENTRY (name)
  63 #define END_CHK(name) END (name)
  64
  65 #ifdef HAVE_CPP_ASM_DEBUGINFO
  66 /* Disable that goop, because we just pass -g through to the assembler
  67    and it generates proper line number information directly.  */
  68 # define STABS_CURRENT_FILE1(name)
  69 # define STABS_CURRENT_FILE(name)
  70 # define STABS_FUN(name)
  71 # define STABS_FUN_END(name)
  72 #else
  73 /* Remove the following two lines once the gdb bug is fixed.  */
  74 #define STABS_CURRENT_FILE(name)                                              \
  75   STABS_CURRENT_FILE1 (#name)
  76 #define STABS_CURRENT_FILE1(name)                                             \
  77   1: .stabs name,100,0,0,1b;
  78 /* Emit stabs definition lines.  We use F(0,1) and define t(0,1) as `int',
  79    the same way gcc does it.  */
  80 #define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
  81 #define STABS_FUN2(name, namestr)                                             \
  82   .stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0;               \
  83   .stabs #namestr,36,0,0,name;
  84 #define STABS_FUN_END(name)                                                   \
  85   1: .stabs "",36,0,0,1b-name;
  86 #endif
  87
  88 /* If compiled for profiling, call `mcount' at the start of each function.  */
  89 #ifdef  PROF
  90 /* The mcount code relies on a normal frame pointer being on the stack
  91    to locate our caller, so push one just for its benefit.  */
  92 #define CALL_MCOUNT \
  93   pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
  94   cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
  95   popl %ebp; cfi_def_cfa (esp, 4);
  96 #else
  97 #define CALL_MCOUNT             /* Do nothing.  */
  98 #endif
  99
 100 /* Since C identifiers are not normally prefixed with an underscore
 101    on this system, the asm identifier `syscall_error' intrudes on the
 102    C name space.  Make sure we use an innocuous name.  */
 103 #define syscall_error   __syscall_error
 104 #define mcount          _mcount
 105
 106 #define PSEUDO(name, syscall_name, args)                                      \
 107   .globl syscall_error;                                                       \
 108 lose: SYSCALL_PIC_SETUP                                                       \
 109   jmp JUMPTARGET(syscall_error);                                              \
 110   ENTRY (name)                                                                \
 111   DO_CALL (syscall_name, args);                                               \
 112   jb lose
 113
 114 #undef  PSEUDO_END
 115 #define PSEUDO_END(name)                                                      \
 116   END (name)
 117
 118 # define SETUP_PIC_REG(reg) \
 119   .ifndef GET_PC_THUNK(reg);                                                  \
 120   .section .gnu.linkonce.t.GET_PC_THUNK(reg),"ax",@progbits;                  \
 121   .globl GET_PC_THUNK(reg);                                                   \
 122   .hidden GET_PC_THUNK(reg);                                                  \
 123   .p2align 4;                                                                 \
 124   .type GET_PC_THUNK(reg),@function;                                          \
 125 GET_PC_THUNK(reg):                                                            \
 126   movl (%esp), %e##reg;                                                       \
 127   ret;                                                                        \
 128   .size GET_PC_THUNK(reg), . - GET_PC_THUNK(reg);                             \
 129   .previous;                                                                  \
 130   .endif;                                                                     \
 131   call GET_PC_THUNK(reg)
 132
 133 # define LOAD_PIC_REG(reg) \
 134   SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
 135
 136 #undef JUMPTARGET
 137 #ifdef PIC
 138 #define JUMPTARGET(name)        name##@PLT
 139 #define SYSCALL_PIC_SETUP \
 140     pushl %ebx;                                                               \
 141     cfi_adjust_cfa_offset (4);                                                \
 142     call 0f;                                                                  \
 143 0:  popl %ebx;                                                                \
 144     cfi_adjust_cfa_offset (-4);                                               \
 145     addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
 146
 147 #else
 148 #define JUMPTARGET(name)        name
 149 #define SYSCALL_PIC_SETUP       /* Nothing.  */
 150 #endif
 151
 152 /* Local label name for asm code. */
 153 #ifndef L
 154 #define L(name)         .L##name
 155 #endif
 156
 157 #define atom_text_section .section ".text.atom", "ax"
 158
 159 #endif  /* __ASSEMBLER__ */