[thirdparty/glibc.git] / sysdeps / i386 / sysdep.h

/* Assembler macros for i386.
   Copyright (C) 1991-93,95,96,98,2002,2003,2005,2006,2011,2012
   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
/* For ELF we need the `.type' directive to make shared libs work right.  */
#define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
#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)							      \
  STABS_CURRENT_FILE1("")						      \
  STABS_CURRENT_FILE(name)						      \
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);				      \
  ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function)			      \
  .align ALIGNARG(4);							      \
  STABS_FUN(name)							      \
  C_LABEL(name)								      \
  cfi_startproc;							      \
  CALL_MCOUNT

#undef	END
#define END(name)							      \
  cfi_endproc;								      \
  ASM_SIZE_DIRECTIVE(name)						      \
  STABS_FUN_END(name)

#define ENTRY_CHK(name) ENTRY (name)
#define END_CHK(name) END (name)

#ifdef HAVE_CPP_ASM_DEBUGINFO
/* Disable that goop, because we just pass -g through to the assembler
   and it generates proper line number information directly.  */
# define STABS_CURRENT_FILE1(name)
# define STABS_CURRENT_FILE(name)
# define STABS_FUN(name)
# define STABS_FUN_END(name)
#else
/* Remove the following two lines once the gdb bug is fixed.  */
#define STABS_CURRENT_FILE(name)					      \
  STABS_CURRENT_FILE1 (#name)
#define STABS_CURRENT_FILE1(name)					      \
  1: .stabs name,100,0,0,1b;
/* Emit stabs definition lines.  We use F(0,1) and define t(0,1) as `int',
   the same way gcc does it.  */
#define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
#define STABS_FUN2(name, namestr)					      \
  .stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0;		      \
  .stabs #namestr,36,0,0,name;
#define STABS_FUN_END(name)						      \
  1: .stabs "",36,0,0,1b-name;
#endif

/* 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__ */
Commit	Line	Data
e75154a6	1	/* Assembler macros for i386.
0269750c	2	Copyright (C) 1991-93,95,96,98,2002,2003,2005,2006,2011,2012
11bf311e	3	Free Software Foundation, Inc.
2c6fe0bd UD	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
41bdb6e2 AJ	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.
2c6fe0bd UD	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
41bdb6e2	14	Lesser General Public License for more details.
2c6fe0bd	15
41bdb6e2	16	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	17	License along with the GNU C Library; if not, see
59ba27a6 PE	18	<http://www.gnu.org/licenses/>. */
e75154a6 RM	19
	20	#include <sysdeps/generic/sysdep.h>
	21
314054ea JM	22	#include <features.h> /* For __GNUC_PREREQ. */
	23
	24	/* It is desirable that the names of PIC thunks match those used by
d4a54ac6 JM	25	GCC so that multiple copies are eliminated by the linker. Because
	26	GCC 4.6 and earlier use __i686 in the names, it is necessary to
	27	override that predefined macro. */
	28	#if defined __i686 && defined __ASSEMBLER__
	29	#undef __i686
	30	#define __i686 __i686
	31	#endif
314054ea JM	32
	33	#ifdef __ASSEMBLER__
	34	# if __GNUC_PREREQ (4, 7)
	35	# define GET_PC_THUNK(reg) __x86.get_pc_thunk.reg
	36	# else
	37	# define GET_PC_THUNK(reg) __i686.get_pc_thunk.reg
	38	# endif
b1da7dd9	39	#else
314054ea JM	40	# if __GNUC_PREREQ (4, 7)
	41	# define GET_PC_THUNK_STR(reg) "__x86.get_pc_thunk." #reg
	42	# else
	43	# define GET_PC_THUNK_STR(reg) "__i686.get_pc_thunk." #reg
	44	# endif
b1da7dd9 JM	45	#endif
b1da7dd9 JM	46
66715f83	47	#ifdef __ASSEMBLER__
e75154a6 RM	48
	49	/* Syntactic details of assembler. */
	50
e75154a6 RM	51	/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
	52	#define ALIGNARG(log2) 1<<log2
	53	/* For ELF we need the `.type' directive to make shared libs work right. */
	54	#define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
ae828bc6	55	#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
e75154a6	56
e75154a6	57
ae828bc6 UD	58	/* Define an entry point visible from C.
	59
	60	There is currently a bug in gdb which prevents us from specifying
	61	incomplete stabs information. Fake some entries here which specify
	62	the current source file. */
e75154a6	63	#define ENTRY(name) \
ae828bc6 UD	64	STABS_CURRENT_FILE1("") \
ae828bc6 UD	65	STABS_CURRENT_FILE(name) \
e75154a6 RM	66	ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \
	67	ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function) \
	68	.align ALIGNARG(4); \
ae828bc6	69	STABS_FUN(name) \
e75154a6	70	C_LABEL(name) \
62d01985	71	cfi_startproc; \
e75154a6 RM	72	CALL_MCOUNT
e75154a6 RM	73
6ed0492f UD	74	#undef END
6ed0492f UD	75	#define END(name) \
62d01985	76	cfi_endproc; \
ae828bc6 UD	77	ASM_SIZE_DIRECTIVE(name) \
	78	STABS_FUN_END(name)
	79
3af48cbd L	80	#define ENTRY_CHK(name) ENTRY (name)
	81	#define END_CHK(name) END (name)
	82
e48f9638 RM	83	#ifdef HAVE_CPP_ASM_DEBUGINFO
	84	/* Disable that goop, because we just pass -g through to the assembler
	85	and it generates proper line number information directly. */
	86	# define STABS_CURRENT_FILE1(name)
	87	# define STABS_CURRENT_FILE(name)
	88	# define STABS_FUN(name)
	89	# define STABS_FUN_END(name)
	90	#else
ae828bc6 UD	91	/* Remove the following two lines once the gdb bug is fixed. */
	92	#define STABS_CURRENT_FILE(name) \
	93	STABS_CURRENT_FILE1 (#name)
	94	#define STABS_CURRENT_FILE1(name) \
	95	1: .stabs name,100,0,0,1b;
	96	/* Emit stabs definition lines. We use F(0,1) and define t(0,1) as `int',
	97	the same way gcc does it. */
	98	#define STABS_FUN(name) STABS_FUN2(name, name##:F(0,1))
	99	#define STABS_FUN2(name, namestr) \
	100	.stabs "int:t(0,1)=r(0,1);-2147483648;2147483647;",128,0,0,0; \
	101	.stabs #namestr,36,0,0,name;
	102	#define STABS_FUN_END(name) \
	103	1: .stabs "",36,0,0,1b-name;
e48f9638	104	#endif
6ed0492f	105
e75154a6 RM	106	/* If compiled for profiling, call `mcount' at the start of each function. */
	107	#ifdef PROF
	108	/* The mcount code relies on a normal frame pointer being on the stack
	109	to locate our caller, so push one just for its benefit. */
	110	#define CALL_MCOUNT \
cb8d9c93	111	pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
62d01985 UD	112	cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
62d01985 UD	113	popl %ebp; cfi_def_cfa (esp, 4);
e75154a6 RM	114	#else
	115	#define CALL_MCOUNT /* Do nothing. */
	116	#endif
	117
e75154a6 RM	118	/* Since C identifiers are not normally prefixed with an underscore
	119	on this system, the asm identifier `syscall_error' intrudes on the
	120	C name space. Make sure we use an innocuous name. */
	121	#define syscall_error __syscall_error
	122	#define mcount _mcount
e75154a6 RM	123
e75154a6 RM	124	#define PSEUDO(name, syscall_name, args) \
e75154a6	125	.globl syscall_error; \
ffa8d2a0 RM	126	lose: SYSCALL_PIC_SETUP \
ffa8d2a0 RM	127	jmp JUMPTARGET(syscall_error); \
e75154a6 RM	128	ENTRY (name) \
	129	DO_CALL (syscall_name, args); \
	130	jb lose
	131
cccda09f UD	132	#undef PSEUDO_END
cccda09f UD	133	#define PSEUDO_END(name) \
6ed0492f	134	END (name)
cccda09f	135
11bf311e	136	# define SETUP_PIC_REG(reg) \
b1da7dd9 JM	137	.ifndef GET_PC_THUNK(reg); \
	138	.section .gnu.linkonce.t.GET_PC_THUNK(reg),"ax",@progbits; \
	139	.globl GET_PC_THUNK(reg); \
	140	.hidden GET_PC_THUNK(reg); \
9a1d9254	141	.p2align 4; \
b1da7dd9 JM	142	.type GET_PC_THUNK(reg),@function; \
b1da7dd9 JM	143	GET_PC_THUNK(reg): \
1f708405 RM	144	movl (%esp), %e##reg; \
1f708405 RM	145	ret; \
b1da7dd9	146	.size GET_PC_THUNK(reg), . - GET_PC_THUNK(reg); \
1f708405 RM	147	.previous; \
1f708405 RM	148	.endif; \
b1da7dd9	149	call GET_PC_THUNK(reg)
1f708405 RM	150
	151	# define LOAD_PIC_REG(reg) \
	152	SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
	153
9a1d9254 JM	154	#undef JUMPTARGET
	155	#ifdef PIC
	156	#define JUMPTARGET(name) name##@PLT
	157	#define SYSCALL_PIC_SETUP \
	158	pushl %ebx; \
	159	cfi_adjust_cfa_offset (4); \
	160	call 0f; \
	161	0: popl %ebx; \
	162	cfi_adjust_cfa_offset (-4); \
	163	addl $_GLOBAL_OFFSET_TABLE+[.-0b], %ebx;
	164
e75154a6 RM	165	#else
	166	#define JUMPTARGET(name) name
	167	#define SYSCALL_PIC_SETUP /* Nothing. */
	168	#endif
	169
ac16e905 UD	170	/* Local label name for asm code. */
ac16e905 UD	171	#ifndef L
ffa8d2a0	172	#define L(name) .L##name
ffa8d2a0	173	#endif
ac16e905	174
ceaa0c5d UD	175	#define atom_text_section .section ".text.atom", "ax"
ceaa0c5d UD	176
d8e0ca50 JM	177	#else /* __ASSEMBLER__ */
	178
	179	# define SETUP_PIC_REG_STR(reg) \
	180	".ifndef " GET_PC_THUNK_STR (reg) "\n" \
	181	".section .gnu.linkonce.t." GET_PC_THUNK_STR (reg) ",\"ax\",@progbits\n" \
	182	".globl " GET_PC_THUNK_STR (reg) "\n" \
	183	".hidden " GET_PC_THUNK_STR (reg) "\n" \
	184	".p2align 4\n" \
	185	".type " GET_PC_THUNK_STR (reg) ",@function\n" \
	186	GET_PC_THUNK_STR (reg) ":" \
	187	"movl (%%esp), %%e" #reg "\n" \
	188	"ret\n" \
	189	".size " GET_PC_THUNK_STR (reg) ", . - " GET_PC_THUNK_STR (reg) "\n" \
	190	".previous\n" \
	191	".endif\n" \
	192	"call " GET_PC_THUNK_STR (reg)
	193
	194	# define LOAD_PIC_REG_STR(reg) \
	195	SETUP_PIC_REG_STR (reg) "\naddl $_GLOBAL_OFFSET_TABLE_, %%e" #reg
	196
66715f83	197	#endif /* __ASSEMBLER__ */