libsanitizer/sanitizer_common/sanitizer_asm.h

   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 #if defined(__ELF__) && defined(__x86_64__) || defined(__i386__) || \
  57     defined(__riscv)
  58 # define ASM_PREEMPTIBLE_SYM(sym) sym@plt
  59 #else
  60 # define ASM_PREEMPTIBLE_SYM(sym) sym
  61 #endif
  62
  63 #if !defined(__APPLE__)
  64 # define ASM_HIDDEN(symbol) .hidden symbol
  65 # if defined(__arm__) || defined(__aarch64__)
  66 #  define ASM_TYPE_FUNCTION(symbol) .type symbol, %function
  67 # else
  68 #  define ASM_TYPE_FUNCTION(symbol) .type symbol, @function
  69 # endif
  70 # define ASM_SIZE(symbol) .size symbol, .-symbol
  71 # define ASM_SYMBOL(symbol) symbol
  72 # define ASM_SYMBOL_INTERCEPTOR(symbol) symbol
  73 # if defined(__i386__) || defined(__powerpc__) || defined(__s390__) || \
  74      defined(__sparc__)
  75 // For details, see interception.h
  76 #  define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
  77 #  define ASM_TRAMPOLINE_ALIAS(symbol, name)                                   \
  78          .weak symbol;                                                         \
  79          .set symbol, ASM_WRAPPER_NAME(name)
  80 #  define ASM_INTERCEPTOR_TRAMPOLINE(name)
  81 #  define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 0
  82 # else  // Architecture supports interceptor trampoline
  83 // Keep trampoline implementation in sync with interception/interception.h
  84 #  define ASM_WRAPPER_NAME(symbol) ___interceptor_##symbol
  85 #  define ASM_TRAMPOLINE_ALIAS(symbol, name)                                   \
  86          .weak symbol;                                                         \
  87          .set symbol, __interceptor_trampoline_##name
  88 #  define ASM_INTERCEPTOR_TRAMPOLINE(name)                                     \
  89          .weak __interceptor_##name;                                           \
  90          .set __interceptor_##name, ASM_WRAPPER_NAME(name);                    \
  91          .globl __interceptor_trampoline_##name;                               \
  92          ASM_TYPE_FUNCTION(__interceptor_trampoline_##name);                   \
  93          __interceptor_trampoline_##name:                                      \
  94                  CFI_STARTPROC;                                                \
  95                  ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name);      \
  96                  CFI_ENDPROC;                                                  \
  97          ASM_SIZE(__interceptor_trampoline_##name)
  98 #  define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 1
  99 # endif  // Architecture supports interceptor trampoline
 100 #else
 101 # define ASM_HIDDEN(symbol)
 102 # define ASM_TYPE_FUNCTION(symbol)
 103 # define ASM_SIZE(symbol)
 104 # define ASM_SYMBOL(symbol) _##symbol
 105 # define ASM_SYMBOL_INTERCEPTOR(symbol) _wrap_##symbol
 106 # define ASM_WRAPPER_NAME(symbol) __interceptor_##symbol
 107 #endif
 108
 109 #if defined(__ELF__) && (defined(__GNU__) || defined(__FreeBSD__) || \
 110                          defined(__Fuchsia__) || defined(__linux__))
 111 // clang-format off
 112 #define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
 113 // clang-format on
 114 #else
 115 #define NO_EXEC_STACK_DIRECTIVE
 116 #endif
 117
 118 #if (defined(__x86_64__) || defined(__i386__)) && defined(__has_include) && __has_include(<cet.h>)
 119 #include <cet.h>
 120 #endif
 121 #ifndef _CET_ENDBR
 122 #define _CET_ENDBR
 123 #endif