about summary refs log tree commit diff
path: root/sysdeps/i386/sysdep.h
blob: 7c8d30a02717358213ed3f68e65ef94d6501e21e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/* 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__
# define GET_PC_THUNK(reg) __x86.get_pc_thunk.reg
#else
# define GET_PC_THUNK_STR(reg) "__x86.get_pc_thunk." #reg
#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__ */