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/* Assembler macros for i386.
Copyright (C) 1991-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdeps/generic/sysdep.h>
#include <features.h> /* For __GNUC_PREREQ. */
/* It is desirable that the names of PIC thunks match those used by
GCC so that multiple copies are eliminated by the linker. Because
GCC 4.6 and earlier use __i686 in the names, it is necessary to
override that predefined macro. */
#if defined __i686 && defined __ASSEMBLER__
#undef __i686
#define __i686 __i686
#endif
#ifdef __ASSEMBLER__
# if __GNUC_PREREQ (4, 7)
# define GET_PC_THUNK(reg) __x86.get_pc_thunk.reg
# else
# define GET_PC_THUNK(reg) __i686.get_pc_thunk.reg
# endif
#else
# if __GNUC_PREREQ (4, 7)
# define GET_PC_THUNK_STR(reg) "__x86.get_pc_thunk." #reg
# else
# define GET_PC_THUNK_STR(reg) "__i686.get_pc_thunk." #reg
# endif
#endif
#ifdef __ASSEMBLER__
/* Syntactic details of assembler. */
/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
#define ALIGNARG(log2) 1<<log2
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
/* Define an entry point visible from C.
There is currently a bug in gdb which prevents us from specifying
incomplete stabs information. Fake some entries here which specify
the current source file. */
#define ENTRY(name) \
.globl C_SYMBOL_NAME(name); \
.type C_SYMBOL_NAME(name),@function; \
.align ALIGNARG(4); \
C_LABEL(name) \
cfi_startproc; \
CALL_MCOUNT
#undef END
#define END(name) \
cfi_endproc; \
ASM_SIZE_DIRECTIVE(name)
#define ENTRY_CHK(name) ENTRY (name)
#define END_CHK(name) END (name)
/* If compiled for profiling, call `mcount' at the start of each function. */
#ifdef PROF
/* The mcount code relies on a normal frame pointer being on the stack
to locate our caller, so push one just for its benefit. */
#define CALL_MCOUNT \
pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
popl %ebp; cfi_def_cfa (esp, 4);
#else
#define CALL_MCOUNT /* Do nothing. */
#endif
/* Since C identifiers are not normally prefixed with an underscore
on this system, the asm identifier `syscall_error' intrudes on the
C name space. Make sure we use an innocuous name. */
#define syscall_error __syscall_error
#define mcount _mcount
#define PSEUDO(name, syscall_name, args) \
.globl syscall_error; \
lose: SYSCALL_PIC_SETUP \
jmp JUMPTARGET(syscall_error); \
ENTRY (name) \
DO_CALL (syscall_name, args); \
jb lose
#undef PSEUDO_END
#define PSEUDO_END(name) \
END (name)
# define SETUP_PIC_REG(reg) \
.ifndef GET_PC_THUNK(reg); \
.section .gnu.linkonce.t.GET_PC_THUNK(reg),"ax",@progbits; \
.globl GET_PC_THUNK(reg); \
.hidden GET_PC_THUNK(reg); \
.p2align 4; \
.type GET_PC_THUNK(reg),@function; \
GET_PC_THUNK(reg): \
movl (%esp), %e##reg; \
ret; \
.size GET_PC_THUNK(reg), . - GET_PC_THUNK(reg); \
.previous; \
.endif; \
call GET_PC_THUNK(reg)
# define LOAD_PIC_REG(reg) \
SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
#undef JUMPTARGET
#ifdef PIC
#define JUMPTARGET(name) name##@PLT
#define SYSCALL_PIC_SETUP \
pushl %ebx; \
cfi_adjust_cfa_offset (4); \
call 0f; \
0: popl %ebx; \
cfi_adjust_cfa_offset (-4); \
addl $_GLOBAL_OFFSET_TABLE_+[.-0b], %ebx;
#else
#define JUMPTARGET(name) name
#define SYSCALL_PIC_SETUP /* Nothing. */
#endif
/* Local label name for asm code. */
#ifndef L
#define L(name) .L##name
#endif
#define atom_text_section .section ".text.atom", "ax"
#else /* __ASSEMBLER__ */
# define SETUP_PIC_REG_STR(reg) \
".ifndef " GET_PC_THUNK_STR (reg) "\n" \
".section .gnu.linkonce.t." GET_PC_THUNK_STR (reg) ",\"ax\",@progbits\n" \
".globl " GET_PC_THUNK_STR (reg) "\n" \
".hidden " GET_PC_THUNK_STR (reg) "\n" \
".p2align 4\n" \
".type " GET_PC_THUNK_STR (reg) ",@function\n" \
GET_PC_THUNK_STR (reg) ":" \
"movl (%%esp), %%e" #reg "\n" \
"ret\n" \
".size " GET_PC_THUNK_STR (reg) ", . - " GET_PC_THUNK_STR (reg) "\n" \
".previous\n" \
".endif\n" \
"call " GET_PC_THUNK_STR (reg)
# define LOAD_PIC_REG_STR(reg) \
SETUP_PIC_REG_STR (reg) "\naddl $_GLOBAL_OFFSET_TABLE_, %%e" #reg
#endif /* __ASSEMBLER__ */
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