libsanitizer/sanitizer_common/sanitizer_stacktrace.h

   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   typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
  71                                     int out_size);
  72 };
  73
  74 // Performance-critical, must be in the header.
  75 ALWAYS_INLINE
  76 uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
  77 #if defined(__arm__)
  78   // T32 (Thumb) branch instructions might be 16 or 32 bit long,
  79   // so we return (pc-2) in that case in order to be safe.
  80   // For A32 mode we return (pc-4) because all instructions are 32 bit long.
  81   return (pc - 3) & (~1);
  82 #elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__)
  83   // PCs are always 4 byte aligned.
  84   return pc - 4;
  85 #elif defined(__sparc__) || defined(__mips__)
  86   return pc - 8;
  87 #elif SANITIZER_RISCV64
  88   // RV-64 has variable instruciton length...
  89   // C extentions gives us 2-byte instructoins
  90   // RV-64 has 4-byte instructions
  91   // + RISCV architecture allows instructions up to 8 bytes
  92   // It seems difficult to figure out the exact instruction length -
  93   // pc - 2 seems like a safe option for the purposes of stack tracing
  94   return pc - 2;
  95 #else
  96   return pc - 1;
  97 #endif
  98 }
  99
 100 // StackTrace that owns the buffer used to store the addresses.
 101 struct BufferedStackTrace : public StackTrace {
 102   uptr trace_buffer[kStackTraceMax];
 103   uptr top_frame_bp;  // Optional bp of a top frame.
 104
 105   BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {}
 106
 107   void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0);
 108
 109   // Get the stack trace with the given pc and bp.
 110   // The pc will be in the position 0 of the resulting stack trace.
 111   // The bp may refer to the current frame or to the caller's frame.
 112   void Unwind(uptr pc, uptr bp, void *context, bool request_fast,
 113               u32 max_depth = kStackTraceMax) {
 114     top_frame_bp = (max_depth > 0) ? bp : 0;
 115     // Small max_depth optimization
 116     if (max_depth <= 1) {
 117       if (max_depth == 1)
 118         trace_buffer[0] = pc;
 119       size = max_depth;
 120       return;
 121     }
 122     UnwindImpl(pc, bp, context, request_fast, max_depth);
 123   }
 124
 125   void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top,
 126               uptr stack_bottom, bool request_fast_unwind);
 127
 128   void Reset() {
 129     *static_cast<StackTrace *>(this) = StackTrace(trace_buffer, 0);
 130     top_frame_bp = 0;
 131   }
 132
 133  private:
 134   // Every runtime defines its own implementation of this method
 135   void UnwindImpl(uptr pc, uptr bp, void *context, bool request_fast,
 136                   u32 max_depth);
 137
 138   // UnwindFast/Slow have platform-specific implementations
 139   void UnwindFast(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,
 140                   u32 max_depth);
 141   void UnwindSlow(uptr pc, u32 max_depth);
 142   void UnwindSlow(uptr pc, void *context, u32 max_depth);
 143
 144   void PopStackFrames(uptr count);
 145   uptr LocatePcInTrace(uptr pc);
 146
 147   BufferedStackTrace(const BufferedStackTrace &) = delete;
 148   void operator=(const BufferedStackTrace &) = delete;
 149
 150   friend class FastUnwindTest;
 151 };
 152
 153 #if defined(__s390x__)
 154 static const uptr kFrameSize = 160;
 155 #elif defined(__s390__)
 156 static const uptr kFrameSize = 96;
 157 #else
 158 static const uptr kFrameSize = 2 * sizeof(uhwptr);
 159 #endif
 160
 161 // Check if given pointer points into allocated stack area.
 162 static inline bool IsValidFrame(uptr frame, uptr stack_top, uptr stack_bottom) {
 163   return frame > stack_bottom && frame < stack_top - kFrameSize;
 164 }
 165
 166 }  // namespace __sanitizer
 167
 168 // Use this macro if you want to print stack trace with the caller
 169 // of the current function in the top frame.
 170 #define GET_CALLER_PC_BP \
 171   uptr bp = GET_CURRENT_FRAME();              \
 172   uptr pc = GET_CALLER_PC();
 173
 174 #define GET_CALLER_PC_BP_SP \
 175   GET_CALLER_PC_BP;                           \
 176   uptr local_stack;                           \
 177   uptr sp = (uptr)&local_stack
 178
 179 // Use this macro if you want to print stack trace with the current
 180 // function in the top frame.
 181 #define GET_CURRENT_PC_BP \
 182   uptr bp = GET_CURRENT_FRAME();              \
 183   uptr pc = StackTrace::GetCurrentPc()
 184
 185 #define GET_CURRENT_PC_BP_SP \
 186   GET_CURRENT_PC_BP;                          \
 187   uptr local_stack;                           \
 188   uptr sp = (uptr)&local_stack
 189
 190
 191 #endif  // SANITIZER_STACKTRACE_H