1 | /* Assembler macros for i386. |
2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <sysdeps/x86/sysdep.h> |
20 | |
21 | /* It is desirable that the names of PIC thunks match those used by |
22 | GCC so that multiple copies are eliminated by the linker. Because |
23 | GCC 4.6 and earlier use __i686 in the names, it is necessary to |
24 | override that predefined macro. */ |
25 | #if defined __i686 && defined __ASSEMBLER__ |
26 | #undef __i686 |
27 | #define __i686 __i686 |
28 | #endif |
29 | |
30 | #ifdef __ASSEMBLER__ |
31 | # define GET_PC_THUNK(reg) __x86.get_pc_thunk.reg |
32 | #else |
33 | # define GET_PC_THUNK_STR(reg) "__x86.get_pc_thunk." #reg |
34 | #endif |
35 | |
36 | #ifdef __ASSEMBLER__ |
37 | |
38 | /* Syntactic details of assembler. */ |
39 | |
40 | /* If compiled for profiling, call `mcount' at the start of each function. */ |
41 | #ifdef PROF |
42 | /* The mcount code relies on a normal frame pointer being on the stack |
43 | to locate our caller, so push one just for its benefit. */ |
44 | #define CALL_MCOUNT \ |
45 | pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \ |
46 | cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \ |
47 | popl %ebp; cfi_def_cfa (esp, 4); |
48 | #else |
49 | #define CALL_MCOUNT /* Do nothing. */ |
50 | #endif |
51 | |
52 | #define PSEUDO(name, syscall_name, args) \ |
53 | .globl syscall_error; \ |
54 | lose: SYSCALL_PIC_SETUP \ |
55 | jmp JUMPTARGET(syscall_error); \ |
56 | ENTRY (name) \ |
57 | DO_CALL (syscall_name, args); \ |
58 | jb lose |
59 | |
60 | # define SETUP_PIC_REG(reg) \ |
61 | .ifndef GET_PC_THUNK(reg); \ |
62 | .section .text.GET_PC_THUNK(reg),"axG",@progbits,GET_PC_THUNK(reg),comdat; \ |
63 | .globl GET_PC_THUNK(reg); \ |
64 | .hidden GET_PC_THUNK(reg); \ |
65 | .p2align 4; \ |
66 | .type GET_PC_THUNK(reg),@function; \ |
67 | GET_PC_THUNK(reg): \ |
68 | movl (%esp), %e##reg; \ |
69 | ret; \ |
70 | .size GET_PC_THUNK(reg), . - GET_PC_THUNK(reg); \ |
71 | .previous; \ |
72 | .endif; \ |
73 | call GET_PC_THUNK(reg) |
74 | |
75 | # define LOAD_PIC_REG(reg) \ |
76 | SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg |
77 | |
78 | #undef JUMPTARGET |
79 | #ifdef PIC |
80 | #define JUMPTARGET(name) name##@PLT |
81 | #define SYSCALL_PIC_SETUP \ |
82 | pushl %ebx; \ |
83 | cfi_adjust_cfa_offset (4); \ |
84 | call 0f; \ |
85 | 0: popl %ebx; \ |
86 | cfi_adjust_cfa_offset (-4); \ |
87 | addl $_GLOBAL_OFFSET_TABLE_+[.-0b], %ebx; |
88 | |
89 | #else |
90 | #define JUMPTARGET(name) name |
91 | #define SYSCALL_PIC_SETUP /* Nothing. */ |
92 | #endif |
93 | |
94 | #else /* __ASSEMBLER__ */ |
95 | |
96 | # define SETUP_PIC_REG_STR(reg) \ |
97 | ".ifndef " GET_PC_THUNK_STR (reg) "\n" \ |
98 | ".section .text." GET_PC_THUNK_STR (reg) ",\"axG\",@progbits," \ |
99 | GET_PC_THUNK_STR (reg) ",comdat\n" \ |
100 | ".globl " GET_PC_THUNK_STR (reg) "\n" \ |
101 | ".hidden " GET_PC_THUNK_STR (reg) "\n" \ |
102 | ".p2align 4\n" \ |
103 | ".type " GET_PC_THUNK_STR (reg) ",@function\n" \ |
104 | GET_PC_THUNK_STR (reg) ":" \ |
105 | "movl (%%esp), %%e" #reg "\n" \ |
106 | "ret\n" \ |
107 | ".size " GET_PC_THUNK_STR (reg) ", . - " GET_PC_THUNK_STR (reg) "\n" \ |
108 | ".previous\n" \ |
109 | ".endif\n" \ |
110 | "call " GET_PC_THUNK_STR (reg) |
111 | |
112 | # define LOAD_PIC_REG_STR(reg) \ |
113 | SETUP_PIC_REG_STR (reg) "\naddl $_GLOBAL_OFFSET_TABLE_, %%e" #reg |
114 | |
115 | #endif /* __ASSEMBLER__ */ |
116 | |