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      1 //===-- sanitizer_stacktrace.h ----------------------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file is shared between AddressSanitizer and ThreadSanitizer
     11 // run-time libraries.
     12 //===----------------------------------------------------------------------===//
     13 #ifndef SANITIZER_STACKTRACE_H
     14 #define SANITIZER_STACKTRACE_H
     15 
     16 #include "sanitizer_internal_defs.h"
     17 
     18 namespace __sanitizer {
     19 
     20 static const u32 kStackTraceMax = 256;
     21 
     22 #if SANITIZER_LINUX &&  (defined(__sparc__) || defined(__mips__))
     23 # define SANITIZER_CAN_FAST_UNWIND 0
     24 #elif SANITIZER_WINDOWS
     25 # define SANITIZER_CAN_FAST_UNWIND 0
     26 #else
     27 # define SANITIZER_CAN_FAST_UNWIND 1
     28 #endif
     29 
     30 // Fast unwind is the only option on Mac for now; we will need to
     31 // revisit this macro when slow unwind works on Mac, see
     32 // https://github.com/google/sanitizers/issues/137
     33 #if SANITIZER_MAC
     34 # define SANITIZER_CAN_SLOW_UNWIND 0
     35 #else
     36 # define SANITIZER_CAN_SLOW_UNWIND 1
     37 #endif
     38 
     39 struct StackTrace {
     40   const uptr *trace;
     41   u32 size;
     42   u32 tag;
     43 
     44   static const int TAG_UNKNOWN = 0;
     45   static const int TAG_ALLOC = 1;
     46   static const int TAG_DEALLOC = 2;
     47   static const int TAG_CUSTOM = 100; // Tool specific tags start here.
     48 
     49   StackTrace() : trace(nullptr), size(0), tag(0) {}
     50   StackTrace(const uptr *trace, u32 size) : trace(trace), size(size), tag(0) {}
     51   StackTrace(const uptr *trace, u32 size, u32 tag)
     52       : trace(trace), size(size), tag(tag) {}
     53 
     54   // Prints a symbolized stacktrace, followed by an empty line.
     55   void Print() const;
     56 
     57   static bool WillUseFastUnwind(bool request_fast_unwind) {
     58     if (!SANITIZER_CAN_FAST_UNWIND)
     59       return false;
     60     else if (!SANITIZER_CAN_SLOW_UNWIND)
     61       return true;
     62     return request_fast_unwind;
     63   }
     64 
     65   static uptr GetCurrentPc();
     66   static inline uptr GetPreviousInstructionPc(uptr pc);
     67   static uptr GetNextInstructionPc(uptr pc);
     68   typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
     69                                     int out_size);
     70 };
     71 
     72 // Performance-critical, must be in the header.
     73 ALWAYS_INLINE
     74 uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
     75 #if defined(__arm__)
     76   // Cancel Thumb bit.
     77   pc = pc & (~1);
     78 #endif
     79 #if defined(__powerpc__) || defined(__powerpc64__)
     80   // PCs are always 4 byte aligned.
     81   return pc - 4;
     82 #elif defined(__sparc__) || defined(__mips__)
     83   return pc - 8;
     84 #else
     85   return pc - 1;
     86 #endif
     87 }
     88 
     89 // StackTrace that owns the buffer used to store the addresses.
     90 struct BufferedStackTrace : public StackTrace {
     91   uptr trace_buffer[kStackTraceMax];
     92   uptr top_frame_bp;  // Optional bp of a top frame.
     93 
     94   BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {}
     95 
     96   void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0);
     97   void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top,
     98               uptr stack_bottom, bool request_fast_unwind);
     99 
    100  private:
    101   void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,
    102                        u32 max_depth);
    103   void SlowUnwindStack(uptr pc, u32 max_depth);
    104   void SlowUnwindStackWithContext(uptr pc, void *context,
    105                                   u32 max_depth);
    106   void PopStackFrames(uptr count);
    107   uptr LocatePcInTrace(uptr pc);
    108 
    109   BufferedStackTrace(const BufferedStackTrace &);
    110   void operator=(const BufferedStackTrace &);
    111 };
    112 
    113 }  // namespace __sanitizer
    114 
    115 // Use this macro if you want to print stack trace with the caller
    116 // of the current function in the top frame.
    117 #define GET_CALLER_PC_BP_SP \
    118   uptr bp = GET_CURRENT_FRAME();              \
    119   uptr pc = GET_CALLER_PC();                  \
    120   uptr local_stack;                           \
    121   uptr sp = (uptr)&local_stack
    122 
    123 #define GET_CALLER_PC_BP \
    124   uptr bp = GET_CURRENT_FRAME();              \
    125   uptr pc = GET_CALLER_PC();
    126 
    127 // Use this macro if you want to print stack trace with the current
    128 // function in the top frame.
    129 #define GET_CURRENT_PC_BP_SP \
    130   uptr bp = GET_CURRENT_FRAME();              \
    131   uptr pc = StackTrace::GetCurrentPc();   \
    132   uptr local_stack;                           \
    133   uptr sp = (uptr)&local_stack
    134 
    135 
    136 #endif  // SANITIZER_STACKTRACE_H
    137