1// Copyright (c) 2008, Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8//     * Redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer.
10//     * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14//     * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29//
30// ---
31// Produces a stack trace for Windows.  Normally, one could use
32// stacktrace_x86-inl.h or stacktrace_x86_64-inl.h -- and indeed, that
33// should work for binaries compiled using MSVC in "debug" mode.
34// However, in "release" mode, Windows uses frame-pointer
35// optimization, which makes getting a stack trace very difficult.
36//
37// There are several approaches one can take.  One is to use Windows
38// intrinsics like StackWalk64.  These can work, but have restrictions
39// on how successful they can be.  Another attempt is to write a
40// version of stacktrace_x86-inl.h that has heuristic support for
41// dealing with FPO, similar to what WinDbg does (see
42// http://www.nynaeve.net/?p=97).
43//
44// The solution we've ended up doing is to call the undocumented
45// windows function RtlCaptureStackBackTrace, which probably doesn't
46// work with FPO but at least is fast, and doesn't require a symbol
47// server.
48//
49// This code is inspired by a patch from David Vitek:
50//   http://code.google.com/p/gperftools/issues/detail?id=83
51
52#ifndef BASE_STACKTRACE_WIN32_INL_H_
53#define BASE_STACKTRACE_WIN32_INL_H_
54// Note: this file is included into stacktrace.cc more than once.
55// Anything that should only be defined once should be here:
56
57#include "config.h"
58#include <windows.h>    // for GetProcAddress and GetModuleHandle
59#include <assert.h>
60
61typedef USHORT NTAPI RtlCaptureStackBackTrace_Function(
62    IN ULONG frames_to_skip,
63    IN ULONG frames_to_capture,
64    OUT PVOID *backtrace,
65    OUT PULONG backtrace_hash);
66
67// Load the function we need at static init time, where we don't have
68// to worry about someone else holding the loader's lock.
69static RtlCaptureStackBackTrace_Function* const RtlCaptureStackBackTrace_fn =
70   (RtlCaptureStackBackTrace_Function*)
71   GetProcAddress(GetModuleHandleA("ntdll.dll"), "RtlCaptureStackBackTrace");
72
73PERFTOOLS_DLL_DECL int GetStackTrace(void** result, int max_depth,
74                                     int skip_count) {
75  if (!RtlCaptureStackBackTrace_fn) {
76    // TODO(csilvers): should we log an error here?
77    return 0;     // can't find a stacktrace with no function to call
78  }
79  return (int)RtlCaptureStackBackTrace_fn(skip_count + 2, max_depth,
80                                          result, 0);
81}
82
83PERFTOOLS_DLL_DECL int GetStackFrames(void** /* pcs */,
84                                      int* /* sizes */,
85                                      int /* max_depth */,
86                                      int /* skip_count */) {
87  assert(0 == "Not yet implemented");
88  return 0;
89}
90
91#endif  // BASE_STACKTRACE_WIN32_INL_H_
92