forked from abseil/abseil-cpp
-
Notifications
You must be signed in to change notification settings - Fork 0
/
stacktrace.h
160 lines (149 loc) · 6.79 KB
/
stacktrace.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Routines to extract the current stack trace. These functions are
// thread-safe and async-signal-safe.
// Note that stack trace functionality is platform dependent and requires
// additional support from the compiler/build system in many cases. (That is,
// this generally only works on platforms/builds that have been specifically
// configured to support it.)
#ifndef ABSL_DEBUGGING_STACKTRACE_H_
#define ABSL_DEBUGGING_STACKTRACE_H_
namespace absl {
// Skips the most recent "skip_count" stack frames (also skips the
// frame generated for the "absl::GetStackFrames" routine itself), and then
// records the pc values for up to the next "max_depth" frames in
// "result", and the corresponding stack frame sizes in "sizes".
// Returns the number of values recorded in "result"/"sizes".
//
// Example:
// main() { foo(); }
// foo() { bar(); }
// bar() {
// void* result[10];
// int sizes[10];
// int depth = absl::GetStackFrames(result, sizes, 10, 1);
// }
//
// The absl::GetStackFrames call will skip the frame for "bar". It will
// return 2 and will produce pc values that map to the following
// procedures:
// result[0] foo
// result[1] main
// (Actually, there may be a few more entries after "main" to account for
// startup procedures.)
// And corresponding stack frame sizes will also be recorded:
// sizes[0] 16
// sizes[1] 16
// (Stack frame sizes of 16 above are just for illustration purposes.)
// Stack frame sizes of 0 or less indicate that those frame sizes couldn't
// be identified.
//
// This routine may return fewer stack frame entries than are
// available. Also note that "result" and "sizes" must both be non-null.
extern int GetStackFrames(void** result, int* sizes, int max_depth,
int skip_count);
// Same as above, but to be used from a signal handler. The "uc" parameter
// should be the pointer to ucontext_t which was passed as the 3rd parameter
// to sa_sigaction signal handler. It may help the unwinder to get a
// better stack trace under certain conditions. The "uc" may safely be null.
//
// If min_dropped_frames is not null, stores in *min_dropped_frames a
// lower bound on the number of dropped stack frames. The stored value is
// guaranteed to be >= 0. The number of real stack frames is guaranteed to
// be >= skip_count + max_depth + *min_dropped_frames.
extern int GetStackFramesWithContext(void** result, int* sizes, int max_depth,
int skip_count, const void* uc,
int* min_dropped_frames);
// This is similar to the absl::GetStackFrames routine, except that it returns
// the stack trace only, and not the stack frame sizes as well.
// Example:
// main() { foo(); }
// foo() { bar(); }
// bar() {
// void* result[10];
// int depth = absl::GetStackTrace(result, 10, 1);
// }
//
// This produces:
// result[0] foo
// result[1] main
// .... ...
//
// "result" must not be null.
extern int GetStackTrace(void** result, int max_depth, int skip_count);
// Same as above, but to be used from a signal handler. The "uc" parameter
// should be the pointer to ucontext_t which was passed as the 3rd parameter
// to sa_sigaction signal handler. It may help the unwinder to get a
// better stack trace under certain conditions. The "uc" may safely be null.
//
// If min_dropped_frames is not null, stores in *min_dropped_frames a
// lower bound on the number of dropped stack frames. The stored value is
// guaranteed to be >= 0. The number of real stack frames is guaranteed to
// be >= skip_count + max_depth + *min_dropped_frames.
extern int GetStackTraceWithContext(void** result, int max_depth,
int skip_count, const void* uc,
int* min_dropped_frames);
// Call this to provide a custom function for unwinding stack frames
// that will be used every time someone invokes one of the static
// GetStack{Frames,Trace}{,WithContext}() functions above.
//
// The arguments passed to the unwinder function will match the
// arguments passed to absl::GetStackFramesWithContext() except that sizes
// will be non-null iff the caller is interested in frame sizes.
//
// If unwinder is null, we revert to the default stack-tracing behavior.
//
// ****************************************************************
// WARNINGS
//
// absl::SetStackUnwinder is not suitable for general purpose use. It is
// provided for custom runtimes.
// Some things to watch out for when calling absl::SetStackUnwinder:
//
// (a) The unwinder may be called from within signal handlers and
// therefore must be async-signal-safe.
//
// (b) Even after a custom stack unwinder has been unregistered, other
// threads may still be in the process of using that unwinder.
// Therefore do not clean up any state that may be needed by an old
// unwinder.
// ****************************************************************
extern void SetStackUnwinder(int (*unwinder)(void** pcs, int* sizes,
int max_depth, int skip_count,
const void* uc,
int* min_dropped_frames));
// Function that exposes built-in stack-unwinding behavior, ignoring
// any calls to absl::SetStackUnwinder().
//
// pcs must NOT be null.
//
// sizes may be null.
// uc may be null.
// min_dropped_frames may be null.
//
// The semantics are the same as the corresponding GetStack*() function in the
// case where absl::SetStackUnwinder() was never called. Equivalents are:
//
// null sizes | non-nullptr sizes
// |==========================================================|
// null uc | GetStackTrace() | GetStackFrames() |
// non-null uc | GetStackTraceWithContext() | GetStackFramesWithContext() |
// |==========================================================|
extern int DefaultStackUnwinder(void** pcs, int* sizes, int max_depth,
int skip_count, const void* uc,
int* min_dropped_frames);
} // namespace absl
#endif // ABSL_DEBUGGING_STACKTRACE_H_