/src/abseil-cpp/absl/debugging/stacktrace.cc
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1 | | // Copyright 2017 The Abseil Authors. |
2 | | // |
3 | | // Licensed under the Apache License, Version 2.0 (the "License"); |
4 | | // you may not use this file except in compliance with the License. |
5 | | // You may obtain a copy of the License at |
6 | | // |
7 | | // https://www.apache.org/licenses/LICENSE-2.0 |
8 | | // |
9 | | // Unless required by applicable law or agreed to in writing, software |
10 | | // distributed under the License is distributed on an "AS IS" BASIS, |
11 | | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | | // See the License for the specific language governing permissions and |
13 | | // limitations under the License. |
14 | | |
15 | | // Produce stack trace. |
16 | | // |
17 | | // There are three different ways we can try to get the stack trace: |
18 | | // |
19 | | // 1) Our hand-coded stack-unwinder. This depends on a certain stack |
20 | | // layout, which is used by gcc (and those systems using a |
21 | | // gcc-compatible ABI) on x86 systems, at least since gcc 2.95. |
22 | | // It uses the frame pointer to do its work. |
23 | | // |
24 | | // 2) The libunwind library. This is still in development, and as a |
25 | | // separate library adds a new dependency, but doesn't need a frame |
26 | | // pointer. It also doesn't call malloc. |
27 | | // |
28 | | // 3) The gdb unwinder -- also the one used by the c++ exception code. |
29 | | // It's obviously well-tested, but has a fatal flaw: it can call |
30 | | // malloc() from the unwinder. This is a problem because we're |
31 | | // trying to use the unwinder to instrument malloc(). |
32 | | // |
33 | | // Note: if you add a new implementation here, make sure it works |
34 | | // correctly when absl::GetStackTrace() is called with max_depth == 0. |
35 | | // Some code may do that. |
36 | | |
37 | | #include "absl/debugging/stacktrace.h" |
38 | | |
39 | | #include <atomic> |
40 | | |
41 | | #include "absl/base/attributes.h" |
42 | | #include "absl/base/port.h" |
43 | | #include "absl/debugging/internal/stacktrace_config.h" |
44 | | |
45 | | #if defined(ABSL_STACKTRACE_INL_HEADER) |
46 | | #include ABSL_STACKTRACE_INL_HEADER |
47 | | #else |
48 | | # error Cannot calculate stack trace: will need to write for your environment |
49 | | |
50 | | # include "absl/debugging/internal/stacktrace_aarch64-inl.inc" |
51 | | # include "absl/debugging/internal/stacktrace_arm-inl.inc" |
52 | | # include "absl/debugging/internal/stacktrace_emscripten-inl.inc" |
53 | | # include "absl/debugging/internal/stacktrace_generic-inl.inc" |
54 | | # include "absl/debugging/internal/stacktrace_powerpc-inl.inc" |
55 | | # include "absl/debugging/internal/stacktrace_riscv-inl.inc" |
56 | | # include "absl/debugging/internal/stacktrace_unimplemented-inl.inc" |
57 | | # include "absl/debugging/internal/stacktrace_win32-inl.inc" |
58 | | # include "absl/debugging/internal/stacktrace_x86-inl.inc" |
59 | | #endif |
60 | | |
61 | | namespace absl { |
62 | | ABSL_NAMESPACE_BEGIN |
63 | | namespace { |
64 | | |
65 | | typedef int (*Unwinder)(void**, int*, int, int, const void*, int*); |
66 | | std::atomic<Unwinder> custom; |
67 | | |
68 | | template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT> |
69 | | ABSL_ATTRIBUTE_ALWAYS_INLINE inline int Unwind(void** result, int* sizes, |
70 | | int max_depth, int skip_count, |
71 | | const void* uc, |
72 | 0 | int* min_dropped_frames) { |
73 | 0 | Unwinder f = &UnwindImpl<IS_STACK_FRAMES, IS_WITH_CONTEXT>; |
74 | 0 | Unwinder g = custom.load(std::memory_order_acquire); |
75 | 0 | if (g != nullptr) f = g; |
76 | | |
77 | | // Add 1 to skip count for the unwinder function itself |
78 | 0 | int size = (*f)(result, sizes, max_depth, skip_count + 1, uc, |
79 | 0 | min_dropped_frames); |
80 | | // To disable tail call to (*f)(...) |
81 | 0 | ABSL_BLOCK_TAIL_CALL_OPTIMIZATION(); |
82 | 0 | return size; |
83 | 0 | } Unexecuted instantiation: stacktrace.cc:int absl::(anonymous namespace)::Unwind<true, false>(void**, int*, int, int, void const*, int*) Unexecuted instantiation: stacktrace.cc:int absl::(anonymous namespace)::Unwind<true, true>(void**, int*, int, int, void const*, int*) Unexecuted instantiation: stacktrace.cc:int absl::(anonymous namespace)::Unwind<false, false>(void**, int*, int, int, void const*, int*) Unexecuted instantiation: stacktrace.cc:int absl::(anonymous namespace)::Unwind<false, true>(void**, int*, int, int, void const*, int*) |
84 | | |
85 | | } // anonymous namespace |
86 | | |
87 | | ABSL_ATTRIBUTE_NOINLINE ABSL_ATTRIBUTE_NO_TAIL_CALL int GetStackFrames( |
88 | 0 | void** result, int* sizes, int max_depth, int skip_count) { |
89 | 0 | return Unwind<true, false>(result, sizes, max_depth, skip_count, nullptr, |
90 | 0 | nullptr); |
91 | 0 | } |
92 | | |
93 | | ABSL_ATTRIBUTE_NOINLINE ABSL_ATTRIBUTE_NO_TAIL_CALL int |
94 | | GetStackFramesWithContext(void** result, int* sizes, int max_depth, |
95 | | int skip_count, const void* uc, |
96 | 0 | int* min_dropped_frames) { |
97 | 0 | return Unwind<true, true>(result, sizes, max_depth, skip_count, uc, |
98 | 0 | min_dropped_frames); |
99 | 0 | } |
100 | | |
101 | | ABSL_ATTRIBUTE_NOINLINE ABSL_ATTRIBUTE_NO_TAIL_CALL int GetStackTrace( |
102 | 0 | void** result, int max_depth, int skip_count) { |
103 | 0 | return Unwind<false, false>(result, nullptr, max_depth, skip_count, nullptr, |
104 | 0 | nullptr); |
105 | 0 | } |
106 | | |
107 | | ABSL_ATTRIBUTE_NOINLINE ABSL_ATTRIBUTE_NO_TAIL_CALL int |
108 | | GetStackTraceWithContext(void** result, int max_depth, int skip_count, |
109 | 0 | const void* uc, int* min_dropped_frames) { |
110 | 0 | return Unwind<false, true>(result, nullptr, max_depth, skip_count, uc, |
111 | 0 | min_dropped_frames); |
112 | 0 | } |
113 | | |
114 | 0 | void SetStackUnwinder(Unwinder w) { |
115 | 0 | custom.store(w, std::memory_order_release); |
116 | 0 | } |
117 | | |
118 | | int DefaultStackUnwinder(void** pcs, int* sizes, int depth, int skip, |
119 | 0 | const void* uc, int* min_dropped_frames) { |
120 | 0 | skip++; // For this function |
121 | 0 | Unwinder f = nullptr; |
122 | 0 | if (sizes == nullptr) { |
123 | 0 | if (uc == nullptr) { |
124 | 0 | f = &UnwindImpl<false, false>; |
125 | 0 | } else { |
126 | 0 | f = &UnwindImpl<false, true>; |
127 | 0 | } |
128 | 0 | } else { |
129 | 0 | if (uc == nullptr) { |
130 | 0 | f = &UnwindImpl<true, false>; |
131 | 0 | } else { |
132 | 0 | f = &UnwindImpl<true, true>; |
133 | 0 | } |
134 | 0 | } |
135 | 0 | volatile int x = 0; |
136 | 0 | int n = (*f)(pcs, sizes, depth, skip, uc, min_dropped_frames); |
137 | 0 | x = 1; (void) x; // To disable tail call to (*f)(...) |
138 | 0 | return n; |
139 | 0 | } |
140 | | |
141 | | ABSL_NAMESPACE_END |
142 | | } // namespace absl |