1//===-- sanitizer_stacktrace.h ----------------------------------*- C++ -*-===//
2//
3// This file is distributed under the University of Illinois Open Source
4// License. See LICENSE.TXT for details.
5//
6//===----------------------------------------------------------------------===//
7//
8// This file is shared between AddressSanitizer and ThreadSanitizer
9// run-time libraries.
10//===----------------------------------------------------------------------===//
11#ifndef SANITIZER_STACKTRACE_H
12#define SANITIZER_STACKTRACE_H
13
14#include "sanitizer_internal_defs.h"
15
16namespace __sanitizer {
17
18static const u32 kStackTraceMax = 256;
19
20#if SANITIZER_LINUX && defined(__mips__)
21# define SANITIZER_CAN_FAST_UNWIND 0
22#elif SANITIZER_WINDOWS
23# define SANITIZER_CAN_FAST_UNWIND 0
24#elif SANITIZER_OPENBSD
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 || SANITIZER_OPENBSD || SANITIZER_RTEMS
34# define SANITIZER_CAN_SLOW_UNWIND 0
35#else
36# define SANITIZER_CAN_SLOW_UNWIND 1
37#endif
38
39struct 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.
73ALWAYS_INLINE
74uptr 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#else
86  return pc - 1;
87#endif
88}
89
90// StackTrace that owns the buffer used to store the addresses.
91struct BufferedStackTrace : public StackTrace {
92  uptr trace_buffer[kStackTraceMax];
93  uptr top_frame_bp;  // Optional bp of a top frame.
94
95  BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {}
96
97  void Init(const uptr *pcs, uptr cnt, uptr extra_top_pc = 0);
98  void Unwind(u32 max_depth, uptr pc, uptr bp, void *context, uptr stack_top,
99              uptr stack_bottom, bool request_fast_unwind);
100
101  void Reset() {
102    *static_cast<StackTrace *>(this) = StackTrace(trace_buffer, 0);
103    top_frame_bp = 0;
104  }
105
106 private:
107  void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,
108                       u32 max_depth);
109  void SlowUnwindStack(uptr pc, u32 max_depth);
110  void SlowUnwindStackWithContext(uptr pc, void *context,
111                                  u32 max_depth);
112  void PopStackFrames(uptr count);
113  uptr LocatePcInTrace(uptr pc);
114
115  BufferedStackTrace(const BufferedStackTrace &) = delete;
116  void operator=(const BufferedStackTrace &) = delete;
117};
118
119// Check if given pointer points into allocated stack area.
120static inline bool IsValidFrame(uptr frame, uptr stack_top, uptr stack_bottom) {
121  return frame > stack_bottom && frame < stack_top - 2 * sizeof (uhwptr);
122}
123
124}  // namespace __sanitizer
125
126// Use this macro if you want to print stack trace with the caller
127// of the current function in the top frame.
128#define GET_CALLER_PC_BP_SP \
129  uptr bp = GET_CURRENT_FRAME();              \
130  uptr pc = GET_CALLER_PC();                  \
131  uptr local_stack;                           \
132  uptr sp = (uptr)&local_stack
133
134#define GET_CALLER_PC_BP \
135  uptr bp = GET_CURRENT_FRAME();              \
136  uptr pc = GET_CALLER_PC();
137
138// Use this macro if you want to print stack trace with the current
139// function in the top frame.
140#define GET_CURRENT_PC_BP_SP \
141  uptr bp = GET_CURRENT_FRAME();              \
142  uptr pc = StackTrace::GetCurrentPc();   \
143  uptr local_stack;                           \
144  uptr sp = (uptr)&local_stack
145
146
147#endif  // SANITIZER_STACKTRACE_H
148