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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(__aarch64__) && defined(__ARM_FEATURE_BTI_DEFAULT)
46# define ASM_STARTPROC CFI_STARTPROC; hint #34
47# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC) "\nhint #34"
48#else
49# define ASM_STARTPROC CFI_STARTPROC
50# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC)
51#endif
52#define ASM_ENDPROC CFI_ENDPROC
53#define C_ASM_ENDPROC SANITIZER_STRINGIFY(CFI_ENDPROC)
54
55#if defined(__x86_64__) || defined(__i386__) || defined(__sparc__)
56# define ASM_TAIL_CALL jmp
57#elif defined(__arm__) || defined(__aarch64__) || defined(__mips__) || \
58 defined(__powerpc__) || defined(__loongarch_lp64)
59# define ASM_TAIL_CALL b
60#elif defined(__s390__)
61# define ASM_TAIL_CALL jg
62#elif defined(__riscv)
63# define ASM_TAIL_CALL tail
64#endif
65
66// Currently, almost all of the shared libraries rely on the value of
67// $t9 to get the address of current function, instead of PCREL, even
68// on MIPSr6. To be compatiable with them, we have to set $t9 properly.
69// MIPS uses GOT to get the address of preemptible functions.
70#if defined(__mips64)
71# define C_ASM_TAIL_CALL(t_func, i_func) \
72 "lui $t8, %hi(%neg(%gp_rel(" t_func ")))\n" \
73 "daddu $t8, $t8, $t9\n" \
74 "daddiu $t8, $t8, %lo(%neg(%gp_rel(" t_func ")))\n" \
75 "ld $t9, %got_disp(" i_func ")($t8)\n" \
76 "jr $t9\n"
77#elif defined(__mips__)
78# define C_ASM_TAIL_CALL(t_func, i_func) \
79 ".set noreorder\n" \
80 ".cpload $t9\n" \
81 ".set reorder\n" \
82 "lw $t9, %got(" i_func ")($gp)\n" \
83 "jr $t9\n"
84#elif defined(ASM_TAIL_CALL)
85# define C_ASM_TAIL_CALL(t_func, i_func) \
86 SANITIZER_STRINGIFY(ASM_TAIL_CALL) " " i_func
87#endif
88
89#if defined(__ELF__) && defined(__x86_64__) || defined(__i386__) || \
90 defined(__riscv)
91# define ASM_PREEMPTIBLE_SYM(sym) sym@plt
92#else
93# define ASM_PREEMPTIBLE_SYM(sym) sym
94#endif
95
96#if !defined(__APPLE__)
97# define ASM_HIDDEN(symbol) .hidden symbol
98# if defined(__arm__) || defined(__aarch64__)
99# define ASM_TYPE_FUNCTION(symbol) .type symbol, %function
100# else
101# define ASM_TYPE_FUNCTION(symbol) .type symbol, @function
102# endif
103# define ASM_SIZE(symbol) .size symbol, .-symbol
104# define ASM_SYMBOL(symbol) symbol
105# define ASM_SYMBOL_INTERCEPTOR(symbol) symbol
106# if defined(__i386__) || defined(__powerpc__) || defined(__s390__) || \
107 defined(__sparc__)
108// For details, see interception.h
109# define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
110# define ASM_TRAMPOLINE_ALIAS(symbol, name) \
111 .weak symbol; \
112 .set symbol, ASM_WRAPPER_NAME(name)
113# define ASM_INTERCEPTOR_TRAMPOLINE(name)
114# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 0
115# else // Architecture supports interceptor trampoline
116// Keep trampoline implementation in sync with interception/interception.h
117# define ASM_WRAPPER_NAME(symbol) ___interceptor_##symbol
118# define ASM_TRAMPOLINE_ALIAS(symbol, name) \
119 .weak symbol; \
120 .set symbol, __interceptor_trampoline_##name
121# define ASM_INTERCEPTOR_TRAMPOLINE(name) \
122 .weak __interceptor_##name; \
123 .set __interceptor_##name, ASM_WRAPPER_NAME(name); \
124 .globl __interceptor_trampoline_##name; \
125 ASM_TYPE_FUNCTION(__interceptor_trampoline_##name); \
126 __interceptor_trampoline_##name: \
127 ASM_STARTPROC; \
128 ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name); \
129 ASM_ENDPROC; \
130 ASM_SIZE(__interceptor_trampoline_##name)
131# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 1
132# endif // Architecture supports interceptor trampoline
133#else
134# define ASM_HIDDEN(symbol)
135# define ASM_TYPE_FUNCTION(symbol)
136# define ASM_SIZE(symbol)
137# define ASM_SYMBOL(symbol) _##symbol
138# define ASM_SYMBOL_INTERCEPTOR(symbol) _wrap_##symbol
139# define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
140#endif
141
142#if defined(__ELF__) && (defined(__GNU__) || defined(__FreeBSD__) || \
143 defined(__Fuchsia__) || defined(__linux__))
144// clang-format off
145#define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
146// clang-format on
147#else
148#define NO_EXEC_STACK_DIRECTIVE
149#endif
150
151#if (defined(__x86_64__) || defined(__i386__)) && defined(__has_include) && __has_include(<cet.h>)
152#include <cet.h>
153#endif
154#ifndef _CET_ENDBR
155#define _CET_ENDBR
156#endif