1 // Copyright 2017 The Abseil Authors.
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
7 // https://www.apache.org/licenses/LICENSE-2.0
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.
15 // Produces a stack trace for Windows. Normally, one could use
16 // stacktrace_x86-inl.h or stacktrace_x86_64-inl.h -- and indeed, that
17 // should work for binaries compiled using MSVC in "debug" mode.
18 // However, in "release" mode, Windows uses frame-pointer
19 // optimization, which makes getting a stack trace very difficult.
21 // There are several approaches one can take. One is to use Windows
22 // intrinsics like StackWalk64. These can work, but have restrictions
23 // on how successful they can be. Another attempt is to write a
24 // version of stacktrace_x86-inl.h that has heuristic support for
25 // dealing with FPO, similar to what WinDbg does (see
26 // http://www.nynaeve.net/?p=97). There are (non-working) examples of
27 // these approaches, complete with TODOs, in stacktrace_win32-inl.h#1
29 // The solution we've ended up doing is to call the undocumented
30 // windows function RtlCaptureStackBackTrace, which probably doesn't
31 // work with FPO but at least is fast, and doesn't require a symbol
34 // This code is inspired by a patch from David Vitek:
35 // https://code.google.com/p/google-perftools/issues/detail?id=83
37 #ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_
38 #define ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_
40 #include <windows.h> // for GetProcAddress and GetModuleHandle
43 typedef USHORT NTAPI RtlCaptureStackBackTrace_Function(
44 IN ULONG frames_to_skip,
45 IN ULONG frames_to_capture,
47 OUT PULONG backtrace_hash);
49 // Load the function we need at static init time, where we don't have
50 // to worry about someone else holding the loader's lock.
51 static RtlCaptureStackBackTrace_Function* const RtlCaptureStackBackTrace_fn =
52 (RtlCaptureStackBackTrace_Function*)
53 GetProcAddress(GetModuleHandleA("ntdll.dll"), "RtlCaptureStackBackTrace");
55 template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
56 static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
57 const void *ucp, int *min_dropped_frames) {
59 if (!RtlCaptureStackBackTrace_fn) {
60 // can't find a stacktrace with no function to call
62 n = (int)RtlCaptureStackBackTrace_fn(skip_count + 2, max_depth, result, 0);
64 if (IS_STACK_FRAMES) {
65 // No implementation for finding out the stack frame sizes yet.
66 memset(sizes, 0, sizeof(*sizes) * n);
68 if (min_dropped_frames != nullptr) {
70 *min_dropped_frames = 0;
76 namespace debugging_internal {
77 bool StackTraceWorksForTest() {
80 } // namespace debugging_internal
83 #endif // ABSL_DEBUGGING_INTERNAL_STACKTRACE_WIN32_INL_H_