1 //===-- sanitizer_stacktrace.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 // This file is shared between AddressSanitizer and ThreadSanitizer 10 // run-time libraries. 11 //===----------------------------------------------------------------------===// 12 #ifndef SANITIZER_STACKTRACE_H 13 #define SANITIZER_STACKTRACE_H 14 15 #include "sanitizer_internal_defs.h" 16 17 namespace __sanitizer { 18 19 struct BufferedStackTrace; 20 21 static const u32 kStackTraceMax = 256; 22 23 #if SANITIZER_LINUX && defined(__mips__) 24 # define SANITIZER_CAN_FAST_UNWIND 0 25 #elif SANITIZER_WINDOWS 26 # define SANITIZER_CAN_FAST_UNWIND 0 27 #elif SANITIZER_OPENBSD 28 # define SANITIZER_CAN_FAST_UNWIND 0 29 #else 30 # define SANITIZER_CAN_FAST_UNWIND 1 31 #endif 32 33 // Fast unwind is the only option on Mac for now; we will need to 34 // revisit this macro when slow unwind works on Mac, see 35 // https://github.com/google/sanitizers/issues/137 36 #if SANITIZER_MAC || SANITIZER_OPENBSD || SANITIZER_RTEMS 37 # define SANITIZER_CAN_SLOW_UNWIND 0 38 #else 39 # define SANITIZER_CAN_SLOW_UNWIND 1 40 #endif 41 42 struct StackTrace { 43 const uptr *trace; 44 u32 size; 45 u32 tag; 46 47 static const int TAG_UNKNOWN = 0; 48 static const int TAG_ALLOC = 1; 49 static const int TAG_DEALLOC = 2; 50 static const int TAG_CUSTOM = 100; // Tool specific tags start here. 51 52 StackTrace() : trace(nullptr), size(0), tag(0) {} 53 StackTrace(const uptr *trace, u32 size) : trace(trace), size(size), tag(0) {} 54 StackTrace(const uptr *trace, u32 size, u32 tag) 55 : trace(trace), size(size), tag(tag) {} 56 57 // Prints a symbolized stacktrace, followed by an empty line. 58 void Print() const; 59 60 static bool WillUseFastUnwind(bool request_fast_unwind) { 61 if (!SANITIZER_CAN_FAST_UNWIND) 62 return false; 63 if (!SANITIZER_CAN_SLOW_UNWIND) 64 return true; 65 return request_fast_unwind; 66 } 67 68 static uptr GetCurrentPc(); 69 static inline uptr GetPreviousInstructionPc(uptr pc); 70 static uptr GetNextInstructionPc(uptr pc); 71 typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer, 72 int out_size); 73 }; 74 75 // Performance-critical, must be in the header. 76 ALWAYS_INLINE 77 uptr StackTrace::GetPreviousInstructionPc(uptr pc) { 78 #if defined(__arm__) 79 // T32 (Thumb) branch instructions might be 16 or 32 bit long, 80 // so we return (pc-2) in that case in order to be safe. 81 // For A32 mode we return (pc-4) because all instructions are 32 bit long. 82 return (pc - 3) & (~1); 83 #elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__) 84 // PCs are always 4 byte aligned. 85 return pc - 4; 86 #elif defined(__sparc__) || defined(__mips__) 87 return pc - 8; 88 #else 89 return pc - 1; 90 #endif 91 } 92 93 // StackTrace that owns the buffer used to store the addresses. 94 struct BufferedStackTrace : public StackTrace { 95 uptr trace_buffer[kStackTraceMax]; 96 uptr top_frame_bp; // Optional bp of a top frame. 97 98 BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {} 99 100 void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0); 101 102 // Get the stack trace with the given pc and bp. 103 // The pc will be in the position 0 of the resulting stack trace. 104 // The bp may refer to the current frame or to the caller's frame. 105 void Unwind(uptr pc, uptr bp, void *context, bool request_fast, 106 u32 max_depth = kStackTraceMax) { 107 top_frame_bp = (max_depth > 0) ? bp : 0; 108 // Small max_depth optimization 109 if (max_depth <= 1) { 110 if (max_depth == 1) 111 trace_buffer[0] = pc; 112 size = max_depth; 113 return; 114 } 115 UnwindImpl(pc, bp, context, request_fast, max_depth); 116 } 117 118 void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top, 119 uptr stack_bottom, bool request_fast_unwind); 120 121 void Reset() { 122 *static_cast<StackTrace *>(this) = StackTrace(trace_buffer, 0); 123 top_frame_bp = 0; 124 } 125 126 private: 127 // Every runtime defines its own implementation of this method 128 void UnwindImpl(uptr pc, uptr bp, void *context, bool request_fast, 129 u32 max_depth); 130 131 // UnwindFast/Slow have platform-specific implementations 132 void UnwindFast(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom, 133 u32 max_depth); 134 void UnwindSlow(uptr pc, u32 max_depth); 135 void UnwindSlow(uptr pc, void *context, u32 max_depth); 136 137 void PopStackFrames(uptr count); 138 uptr LocatePcInTrace(uptr pc); 139 140 BufferedStackTrace(const BufferedStackTrace &) = delete; 141 void operator=(const BufferedStackTrace &) = delete; 142 143 friend class FastUnwindTest; 144 }; 145 146 // Check if given pointer points into allocated stack area. 147 static inline bool IsValidFrame(uptr frame, uptr stack_top, uptr stack_bottom) { 148 return frame > stack_bottom && frame < stack_top - 2 * sizeof (uhwptr); 149 } 150 151 } // namespace __sanitizer 152 153 // Use this macro if you want to print stack trace with the caller 154 // of the current function in the top frame. 155 #define GET_CALLER_PC_BP \ 156 uptr bp = GET_CURRENT_FRAME(); \ 157 uptr pc = GET_CALLER_PC(); 158 159 #define GET_CALLER_PC_BP_SP \ 160 GET_CALLER_PC_BP; \ 161 uptr local_stack; \ 162 uptr sp = (uptr)&local_stack 163 164 // Use this macro if you want to print stack trace with the current 165 // function in the top frame. 166 #define GET_CURRENT_PC_BP \ 167 uptr bp = GET_CURRENT_FRAME(); \ 168 uptr pc = StackTrace::GetCurrentPc() 169 170 #define GET_CURRENT_PC_BP_SP \ 171 GET_CURRENT_PC_BP; \ 172 uptr local_stack; \ 173 uptr sp = (uptr)&local_stack 174 175 176 #endif // SANITIZER_STACKTRACE_H 177