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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
//===--- CrashRecoveryContext.h - Crash Recovery ----------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
#define LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
#include <string>
namespace llvm {
class StringRef;
class CrashRecoveryContextCleanup;
/// \brief Crash recovery helper object.
///
/// This class implements support for running operations in a safe context so
/// that crashes (memory errors, stack overflow, assertion violations) can be
/// detected and control restored to the crashing thread. Crash detection is
/// purely "best effort", the exact set of failures which can be recovered from
/// is platform dependent.
///
/// Clients make use of this code by first calling
/// CrashRecoveryContext::Enable(), and then executing unsafe operations via a
/// CrashRecoveryContext object. For example:
///
/// void actual_work(void *);
///
/// void foo() {
/// CrashRecoveryContext CRC;
///
/// if (!CRC.RunSafely(actual_work, 0)) {
/// ... a crash was detected, report error to user ...
/// }
///
/// ... no crash was detected ...
/// }
///
/// Crash recovery contexts may not be nested.
class CrashRecoveryContext {
void *Impl;
CrashRecoveryContextCleanup *head;
public:
CrashRecoveryContext() : Impl(0), head(0) {}
~CrashRecoveryContext();
void registerCleanup(CrashRecoveryContextCleanup *cleanup);
void unregisterCleanup(CrashRecoveryContextCleanup *cleanup);
/// \brief Enable crash recovery.
static void Enable();
/// \brief Disable crash recovery.
static void Disable();
/// \brief Return the active context, if the code is currently executing in a
/// thread which is in a protected context.
static CrashRecoveryContext *GetCurrent();
/// \brief Return true if the current thread is recovering from a
/// crash.
static bool isRecoveringFromCrash();
/// \brief Execute the provide callback function (with the given arguments) in
/// a protected context.
///
/// \return True if the function completed successfully, and false if the
/// function crashed (or HandleCrash was called explicitly). Clients should
/// make as little assumptions as possible about the program state when
/// RunSafely has returned false. Clients can use getBacktrace() to retrieve
/// the backtrace of the crash on failures.
bool RunSafely(void (*Fn)(void*), void *UserData);
/// \brief Execute the provide callback function (with the given arguments) in
/// a protected context which is run in another thread (optionally with a
/// requested stack size).
///
/// See RunSafely() and llvm_execute_on_thread().
bool RunSafelyOnThread(void (*Fn)(void*), void *UserData,
unsigned RequestedStackSize = 0);
/// \brief Explicitly trigger a crash recovery in the current process, and
/// return failure from RunSafely(). This function does not return.
void HandleCrash();
/// \brief Return a string containing the backtrace where the crash was
/// detected; or empty if the backtrace wasn't recovered.
///
/// This function is only valid when a crash has been detected (i.e.,
/// RunSafely() has returned false.
const std::string &getBacktrace() const;
};
class CrashRecoveryContextCleanup {
protected:
CrashRecoveryContext *context;
CrashRecoveryContextCleanup(CrashRecoveryContext *context)
: context(context), cleanupFired(false) {}
public:
bool cleanupFired;
virtual ~CrashRecoveryContextCleanup();
virtual void recoverResources() = 0;
CrashRecoveryContext *getContext() const {
return context;
}
private:
friend class CrashRecoveryContext;
CrashRecoveryContextCleanup *prev, *next;
};
template<typename DERIVED, typename T>
class CrashRecoveryContextCleanupBase : public CrashRecoveryContextCleanup {
protected:
T *resource;
CrashRecoveryContextCleanupBase(CrashRecoveryContext *context, T* resource)
: CrashRecoveryContextCleanup(context), resource(resource) {}
public:
static DERIVED *create(T *x) {
if (x) {
if (CrashRecoveryContext *context = CrashRecoveryContext::GetCurrent())
return new DERIVED(context, x);
}
return 0;
}
};
template <typename T>
class CrashRecoveryContextDestructorCleanup : public
CrashRecoveryContextCleanupBase<CrashRecoveryContextDestructorCleanup<T>, T> {
public:
CrashRecoveryContextDestructorCleanup(CrashRecoveryContext *context,
T *resource)
: CrashRecoveryContextCleanupBase<
CrashRecoveryContextDestructorCleanup<T>, T>(context, resource) {}
virtual void recoverResources() {
this->resource->~T();
}
};
template <typename T>
class CrashRecoveryContextDeleteCleanup : public
CrashRecoveryContextCleanupBase<CrashRecoveryContextDeleteCleanup<T>, T> {
public:
CrashRecoveryContextDeleteCleanup(CrashRecoveryContext *context, T *resource)
: CrashRecoveryContextCleanupBase<
CrashRecoveryContextDeleteCleanup<T>, T>(context, resource) {}
virtual void recoverResources() {
delete this->resource;
}
};
template <typename T>
class CrashRecoveryContextReleaseRefCleanup : public
CrashRecoveryContextCleanupBase<CrashRecoveryContextReleaseRefCleanup<T>, T>
{
public:
CrashRecoveryContextReleaseRefCleanup(CrashRecoveryContext *context,
T *resource)
: CrashRecoveryContextCleanupBase<CrashRecoveryContextReleaseRefCleanup<T>,
T>(context, resource) {}
virtual void recoverResources() {
this->resource->Release();
}
};
template <typename T, typename Cleanup = CrashRecoveryContextDeleteCleanup<T> >
class CrashRecoveryContextCleanupRegistrar {
CrashRecoveryContextCleanup *cleanup;
public:
CrashRecoveryContextCleanupRegistrar(T *x)
: cleanup(Cleanup::create(x)) {
if (cleanup)
cleanup->getContext()->registerCleanup(cleanup);
}
~CrashRecoveryContextCleanupRegistrar() {
if (cleanup && !cleanup->cleanupFired)
cleanup->getContext()->unregisterCleanup(cleanup);
}
};
}
#endif
|
