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 #include "sanitizer_platform.h" 17 18 namespace __sanitizer { 19 20 struct BufferedStackTrace; 21 22 static const u32 kStackTraceMax = 256; 23 24 #if SANITIZER_LINUX && defined(__mips__) 25 # define SANITIZER_CAN_FAST_UNWIND 0 26 #elif SANITIZER_WINDOWS 27 # define SANITIZER_CAN_FAST_UNWIND 0 28 #else 29 # define SANITIZER_CAN_FAST_UNWIND 1 30 #endif 31 32 // Fast unwind is the only option on Mac for now; we will need to 33 // revisit this macro when slow unwind works on Mac, see 34 // https://github.com/google/sanitizers/issues/137 35 #if SANITIZER_MAC || SANITIZER_RTEMS 36 # define SANITIZER_CAN_SLOW_UNWIND 0 37 #else 38 # define SANITIZER_CAN_SLOW_UNWIND 1 39 #endif 40 41 struct StackTrace { 42 const uptr *trace; 43 u32 size; 44 u32 tag; 45 46 static const int TAG_UNKNOWN = 0; 47 static const int TAG_ALLOC = 1; 48 static const int TAG_DEALLOC = 2; 49 static const int TAG_CUSTOM = 100; // Tool specific tags start here. 50 51 StackTrace() : trace(nullptr), size(0), tag(0) {} 52 StackTrace(const uptr *trace, u32 size) : trace(trace), size(size), tag(0) {} 53 StackTrace(const uptr *trace, u32 size, u32 tag) 54 : trace(trace), size(size), tag(tag) {} 55 56 // Prints a symbolized stacktrace, followed by an empty line. 57 void Print() const; 58 59 static bool WillUseFastUnwind(bool request_fast_unwind) { 60 if (!SANITIZER_CAN_FAST_UNWIND) 61 return false; 62 if (!SANITIZER_CAN_SLOW_UNWIND) 63 return true; 64 return request_fast_unwind; 65 } 66 67 static uptr GetCurrentPc(); 68 static inline uptr GetPreviousInstructionPc(uptr pc); 69 static uptr GetNextInstructionPc(uptr pc); 70 }; 71 72 // Performance-critical, must be in the header. 73 ALWAYS_INLINE 74 uptr StackTrace::GetPreviousInstructionPc(uptr pc) { 75 #if defined(__arm__) 76 // T32 (Thumb) branch instructions might be 16 or 32 bit long, 77 // so we return (pc-2) in that case in order to be safe. 78 // For A32 mode we return (pc-4) because all instructions are 32 bit long. 79 return (pc - 3) & (~1); 80 #elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__) 81 // PCs are always 4 byte aligned. 82 return pc - 4; 83 #elif defined(__sparc__) || defined(__mips__) 84 return pc - 8; 85 #elif SANITIZER_RISCV64 86 // RV-64 has variable instruciton length... 87 // C extentions gives us 2-byte instructoins 88 // RV-64 has 4-byte instructions 89 // + RISCV architecture allows instructions up to 8 bytes 90 // It seems difficult to figure out the exact instruction length - 91 // pc - 2 seems like a safe option for the purposes of stack tracing 92 return pc - 2; 93 #else 94 return pc - 1; 95 #endif 96 } 97 98 // StackTrace that owns the buffer used to store the addresses. 99 struct BufferedStackTrace : public StackTrace { 100 uptr trace_buffer[kStackTraceMax]; 101 uptr top_frame_bp; // Optional bp of a top frame. 102 103 BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {} 104 105 void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0); 106 107 // Get the stack trace with the given pc and bp. 108 // The pc will be in the position 0 of the resulting stack trace. 109 // The bp may refer to the current frame or to the caller's frame. 110 void Unwind(uptr pc, uptr bp, void *context, bool request_fast, 111 u32 max_depth = kStackTraceMax) { 112 top_frame_bp = (max_depth > 0) ? bp : 0; 113 // Small max_depth optimization 114 if (max_depth <= 1) { 115 if (max_depth == 1) 116 trace_buffer[0] = pc; 117 size = max_depth; 118 return; 119 } 120 UnwindImpl(pc, bp, context, request_fast, max_depth); 121 } 122 123 void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top, 124 uptr stack_bottom, bool request_fast_unwind); 125 126 void Reset() { 127 *static_cast<StackTrace *>(this) = StackTrace(trace_buffer, 0); 128 top_frame_bp = 0; 129 } 130 131 private: 132 // Every runtime defines its own implementation of this method 133 void UnwindImpl(uptr pc, uptr bp, void *context, bool request_fast, 134 u32 max_depth); 135 136 // UnwindFast/Slow have platform-specific implementations 137 void UnwindFast(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom, 138 u32 max_depth); 139 void UnwindSlow(uptr pc, u32 max_depth); 140 void UnwindSlow(uptr pc, void *context, u32 max_depth); 141 142 void PopStackFrames(uptr count); 143 uptr LocatePcInTrace(uptr pc); 144 145 BufferedStackTrace(const BufferedStackTrace &) = delete; 146 void operator=(const BufferedStackTrace &) = delete; 147 148 friend class FastUnwindTest; 149 }; 150 151 #if defined(__s390x__) 152 static const uptr kFrameSize = 160; 153 #elif defined(__s390__) 154 static const uptr kFrameSize = 96; 155 #else 156 static const uptr kFrameSize = 2 * sizeof(uhwptr); 157 #endif 158 159 // Check if given pointer points into allocated stack area. 160 static inline bool IsValidFrame(uptr frame, uptr stack_top, uptr stack_bottom) { 161 return frame > stack_bottom && frame < stack_top - kFrameSize; 162 } 163 164 } // namespace __sanitizer 165 166 // Use this macro if you want to print stack trace with the caller 167 // of the current function in the top frame. 168 #define GET_CALLER_PC_BP \ 169 uptr bp = GET_CURRENT_FRAME(); \ 170 uptr pc = GET_CALLER_PC(); 171 172 #define GET_CALLER_PC_BP_SP \ 173 GET_CALLER_PC_BP; \ 174 uptr local_stack; \ 175 uptr sp = (uptr)&local_stack 176 177 // Use this macro if you want to print stack trace with the current 178 // function in the top frame. 179 #define GET_CURRENT_PC_BP \ 180 uptr bp = GET_CURRENT_FRAME(); \ 181 uptr pc = StackTrace::GetCurrentPc() 182 183 #define GET_CURRENT_PC_BP_SP \ 184 GET_CURRENT_PC_BP; \ 185 uptr local_stack; \ 186 uptr sp = (uptr)&local_stack 187 188 189 #endif // SANITIZER_STACKTRACE_H 190