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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-exception6//7//===----------------------------------------------------------------------===//8//9// This file is shared between AddressSanitizer and ThreadSanitizer10// run-time libraries.11//===----------------------------------------------------------------------===//12#ifndef SANITIZER_STACKTRACE_H13#define SANITIZER_STACKTRACE_H14 15#include "sanitizer_common.h"16#include "sanitizer_internal_defs.h"17#include "sanitizer_platform.h"18 19namespace __sanitizer {20 21struct BufferedStackTrace;22 23static const u32 kStackTraceMax = 255;24 25#if SANITIZER_LINUX && defined(__mips__)26# define SANITIZER_CAN_FAST_UNWIND 027#elif SANITIZER_WINDOWS28# define SANITIZER_CAN_FAST_UNWIND 029#else30# define SANITIZER_CAN_FAST_UNWIND 131#endif32 33// Fast unwind is the only option on Mac for now; we will need to34// revisit this macro when slow unwind works on Mac, see35// https://github.com/google/sanitizers/issues/13736#if SANITIZER_APPLE37# define SANITIZER_CAN_SLOW_UNWIND 038#else39# define SANITIZER_CAN_SLOW_UNWIND 140#endif41 42struct 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 // Prints a symbolized stacktrace to the output string, followed by an empty61 // line.62 void PrintTo(InternalScopedString *output) const;63 64 // Prints a symbolized stacktrace to the output buffer, followed by an empty65 // line. Returns the number of symbols that should have been written to buffer66 // (not including trailing '\0'). Thus, the string is truncated iff return67 // value is not less than "out_buf_size".68 uptr PrintTo(char *out_buf, uptr out_buf_size) const;69 70 static bool WillUseFastUnwind(bool request_fast_unwind) {71 if (!SANITIZER_CAN_FAST_UNWIND)72 return false;73 if (!SANITIZER_CAN_SLOW_UNWIND)74 return true;75 return request_fast_unwind;76 }77 78 static uptr GetCurrentPc();79 static inline uptr GetPreviousInstructionPc(uptr pc);80 static uptr GetNextInstructionPc(uptr pc);81};82 83// Performance-critical, must be in the header.84ALWAYS_INLINE85uptr StackTrace::GetPreviousInstructionPc(uptr pc) {86#if defined(__arm__)87 // T32 (Thumb) branch instructions might be 16 or 32 bit long,88 // so we return (pc-2) in that case in order to be safe.89 // For A32 mode we return (pc-4) because all instructions are 32 bit long.90 return (pc - 3) & (~1);91#elif defined(__sparc__) || defined(__mips__)92 return pc - 8;93#elif SANITIZER_RISCV6494 // RV-64 has variable instruction length...95 // C extentions gives us 2-byte instructoins96 // RV-64 has 4-byte instructions97 // + RISC-V architecture allows instructions up to 8 bytes98 // It seems difficult to figure out the exact instruction length -99 // pc - 2 seems like a safe option for the purposes of stack tracing100 return pc - 2;101#elif SANITIZER_S390 || SANITIZER_I386 || SANITIZER_X32 || SANITIZER_X64102 return pc - 1;103#else104 return pc - 4;105#endif106}107 108// StackTrace that owns the buffer used to store the addresses.109struct BufferedStackTrace : public StackTrace {110 uptr trace_buffer[kStackTraceMax];111 uptr top_frame_bp; // Optional bp of a top frame.112 113 BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {}114 115 void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0);116 117 // Get the stack trace with the given pc and bp.118 // The pc will be in the position 0 of the resulting stack trace.119 // The bp may refer to the current frame or to the caller's frame.120 void Unwind(uptr pc, uptr bp, void *context, bool request_fast,121 u32 max_depth = kStackTraceMax) {122 top_frame_bp = (max_depth > 0) ? bp : 0;123 // Small max_depth optimization124 if (max_depth <= 1) {125 if (max_depth == 1)126 trace_buffer[0] = pc;127 size = max_depth;128 return;129 }130 UnwindImpl(pc, bp, context, request_fast, max_depth);131 }132 133 void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top,134 uptr stack_bottom, bool request_fast_unwind);135 136 void Reset() {137 *static_cast<StackTrace *>(this) = StackTrace(trace_buffer, 0);138 top_frame_bp = 0;139 }140 141 private:142 // Every runtime defines its own implementation of this method143 void UnwindImpl(uptr pc, uptr bp, void *context, bool request_fast,144 u32 max_depth);145 146 // UnwindFast/Slow have platform-specific implementations147 void UnwindFast(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,148 u32 max_depth);149 void UnwindSlow(uptr pc, u32 max_depth);150 void UnwindSlow(uptr pc, void *context, u32 max_depth);151 152 void PopStackFrames(uptr count);153 uptr LocatePcInTrace(uptr pc);154 155 BufferedStackTrace(const BufferedStackTrace &) = delete;156 void operator=(const BufferedStackTrace &) = delete;157 158 friend class FastUnwindTest;159};160 161#if defined(__s390x__)162static const uptr kFrameSize = 160;163#elif defined(__s390__)164static const uptr kFrameSize = 96;165#else166static const uptr kFrameSize = 2 * sizeof(uhwptr);167#endif168 169// Check if given pointer points into allocated stack area.170static inline bool IsValidFrame(uptr frame, uptr stack_top, uptr stack_bottom) {171 return frame > stack_bottom && frame < stack_top - kFrameSize;172}173 174} // namespace __sanitizer175 176// Use this macro if you want to print stack trace with the caller177// of the current function in the top frame.178#define GET_CALLER_PC_BP \179 uptr bp = GET_CURRENT_FRAME(); \180 uptr pc = GET_CALLER_PC();181 182#define GET_CALLER_PC_BP_SP \183 GET_CALLER_PC_BP; \184 uptr local_stack; \185 uptr sp = (uptr)&local_stack186 187// Use this macro if you want to print stack trace with the current188// function in the top frame.189#define GET_CURRENT_PC_BP \190 uptr bp = GET_CURRENT_FRAME(); \191 uptr pc = StackTrace::GetCurrentPc()192 193#define GET_CURRENT_PC_BP_SP \194 GET_CURRENT_PC_BP; \195 uptr local_stack; \196 uptr sp = (uptr)&local_stack197 198// GET_CURRENT_PC() is equivalent to StackTrace::GetCurrentPc().199// Optimized x86 version is faster than GetCurrentPc because200// it does not involve a function call, instead it reads RIP register.201// Reads of RIP by an instruction return RIP pointing to the next202// instruction, which is exactly what we want here, thus 0 offset.203// It needs to be a macro because otherwise we will get the name204// of this function on the top of most stacks. Attribute artificial205// does not do what it claims to do, unfortunatley. And attribute206// __nodebug__ is clang-only. If we would have an attribute that207// would remove this function from debug info, we could simply make208// StackTrace::GetCurrentPc() faster.209#if defined(__x86_64__)210# define GET_CURRENT_PC() \211 (__extension__({ \212 uptr pc; \213 asm("lea 0(%%rip), %0" : "=r"(pc)); \214 pc; \215 }))216#else217# define GET_CURRENT_PC() StackTrace::GetCurrentPc()218#endif219 220#endif // SANITIZER_STACKTRACE_H221