1//===-- sanitizer_asm.h -----------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Various support for assembler.
10//
11//===----------------------------------------------------------------------===//
12
13// Some toolchains do not support .cfi asm directives, so we have to hide
14// them inside macros.
15#if defined(__clang__) || \
16 (defined(__GNUC__) && defined(__GCC_HAVE_DWARF2_CFI_ASM))
17 // GCC defined __GCC_HAVE_DWARF2_CFI_ASM if it supports CFI.
18 // Clang seems to support CFI by default (or not?).
19 // We need two versions of macros: for inline asm and standalone asm files.
20# define CFI_INL_ADJUST_CFA_OFFSET(n) ".cfi_adjust_cfa_offset " #n ";"
21
22# define CFI_STARTPROC .cfi_startproc
23# define CFI_ENDPROC .cfi_endproc
24# define CFI_ADJUST_CFA_OFFSET(n) .cfi_adjust_cfa_offset n
25# define CFI_DEF_CFA_OFFSET(n) .cfi_def_cfa_offset n
26# define CFI_REL_OFFSET(reg, n) .cfi_rel_offset reg, n
27# define CFI_OFFSET(reg, n) .cfi_offset reg, n
28# define CFI_DEF_CFA_REGISTER(reg) .cfi_def_cfa_register reg
29# define CFI_DEF_CFA(reg, n) .cfi_def_cfa reg, n
30# define CFI_RESTORE(reg) .cfi_restore reg
31
32#else // No CFI
33# define CFI_INL_ADJUST_CFA_OFFSET(n)
34# define CFI_STARTPROC
35# define CFI_ENDPROC
36# define CFI_ADJUST_CFA_OFFSET(n)
37# define CFI_DEF_CFA_OFFSET(n)
38# define CFI_REL_OFFSET(reg, n)
39# define CFI_OFFSET(reg, n)
40# define CFI_DEF_CFA_REGISTER(reg)
41# define CFI_DEF_CFA(reg, n)
42# define CFI_RESTORE(reg)
43#endif
44
45#if defined(__x86_64__) || defined(__i386__) || defined(__sparc__)
46# define ASM_TAIL_CALL jmp
47#elif defined(__arm__) || defined(__aarch64__) || defined(__mips__) || \
48 defined(__powerpc__) || defined(__loongarch_lp64)
49# define ASM_TAIL_CALL b
50#elif defined(__s390__)
51# define ASM_TAIL_CALL jg
52#elif defined(__riscv)
53# define ASM_TAIL_CALL tail
54#endif
55
56// Currently, almost all of the shared libraries rely on the value of
57// $t9 to get the address of current function, instead of PCREL, even
58// on MIPSr6. To be compatiable with them, we have to set $t9 properly.
59// MIPS uses GOT to get the address of preemptible functions.
60#if defined(__mips64)
61# define C_ASM_TAIL_CALL(t_func, i_func) \
62 "lui $t8, %hi(%neg(%gp_rel(" t_func ")))\n" \
63 "daddu $t8, $t8, $t9\n" \
64 "daddiu $t8, $t8, %lo(%neg(%gp_rel(" t_func ")))\n" \
65 "ld $t9, %got_disp(" i_func ")($t8)\n" \
66 "jr $t9\n"
67#elif defined(__mips__)
68# define C_ASM_TAIL_CALL(t_func, i_func) \
69 ".set noreorder\n" \
70 ".cpload $t9\n" \
71 ".set reorder\n" \
72 "lw $t9, %got(" i_func ")($gp)\n" \
73 "jr $t9\n"
74#elif defined(ASM_TAIL_CALL)
75# define C_ASM_TAIL_CALL(t_func, i_func) \
76 SANITIZER_STRINGIFY(ASM_TAIL_CALL) " " i_func
77#endif
78
79#if defined(__ELF__) && defined(__x86_64__) || defined(__i386__) || \
80 defined(__riscv)
81# define ASM_PREEMPTIBLE_SYM(sym) sym@plt
82#else
83# define ASM_PREEMPTIBLE_SYM(sym) sym
84#endif
85
86#if !defined(__APPLE__)
87# define ASM_HIDDEN(symbol) .hidden symbol
88# if defined(__arm__) || defined(__aarch64__)
89# define ASM_TYPE_FUNCTION(symbol) .type symbol, %function
90# else
91# define ASM_TYPE_FUNCTION(symbol) .type symbol, @function
92# endif
93# define ASM_SIZE(symbol) .size symbol, .-symbol
94# define ASM_SYMBOL(symbol) symbol
95# define ASM_SYMBOL_INTERCEPTOR(symbol) symbol
96# if defined(__i386__) || defined(__powerpc__) || defined(__s390__) || \
97 defined(__sparc__)
98// For details, see interception.h
99# define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
100# define ASM_TRAMPOLINE_ALIAS(symbol, name) \
101 .weak symbol; \
102 .set symbol, ASM_WRAPPER_NAME(name)
103# define ASM_INTERCEPTOR_TRAMPOLINE(name)
104# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 0
105# else // Architecture supports interceptor trampoline
106// Keep trampoline implementation in sync with interception/interception.h
107# define ASM_WRAPPER_NAME(symbol) ___interceptor_##symbol
108# define ASM_TRAMPOLINE_ALIAS(symbol, name) \
109 .weak symbol; \
110 .set symbol, __interceptor_trampoline_##name
111# define ASM_INTERCEPTOR_TRAMPOLINE(name) \
112 .weak __interceptor_##name; \
113 .set __interceptor_##name, ASM_WRAPPER_NAME(name); \
114 .globl __interceptor_trampoline_##name; \
115 ASM_TYPE_FUNCTION(__interceptor_trampoline_##name); \
116 __interceptor_trampoline_##name: \
117 CFI_STARTPROC; \
118 ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name); \
119 CFI_ENDPROC; \
120 ASM_SIZE(__interceptor_trampoline_##name)
121# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 1
122# endif // Architecture supports interceptor trampoline
123#else
124# define ASM_HIDDEN(symbol)
125# define ASM_TYPE_FUNCTION(symbol)
126# define ASM_SIZE(symbol)
127# define ASM_SYMBOL(symbol) _##symbol
128# define ASM_SYMBOL_INTERCEPTOR(symbol) _wrap_##symbol
129# define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
130#endif
131
132#if defined(__ELF__) && (defined(__GNU__) || defined(__FreeBSD__) || \
133 defined(__Fuchsia__) || defined(__linux__))
134// clang-format off
135#define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
136// clang-format on
137#else
138#define NO_EXEC_STACK_DIRECTIVE
139#endif
140
141#if (defined(__x86_64__) || defined(__i386__)) && defined(__has_include) && __has_include(<cet.h>)
142#include <cet.h>
143#endif
144#ifndef _CET_ENDBR
145#define _CET_ENDBR
146#endif
147

source code of compiler-rt/lib/sanitizer_common/sanitizer_asm.h