1 //===--- CrashRecoveryContext.h - Crash Recovery ----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
11 #define LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
18 class CrashRecoveryContextCleanup;
20 /// \brief Crash recovery helper object.
22 /// This class implements support for running operations in a safe context so
23 /// that crashes (memory errors, stack overflow, assertion violations) can be
24 /// detected and control restored to the crashing thread. Crash detection is
25 /// purely "best effort", the exact set of failures which can be recovered from
26 /// is platform dependent.
28 /// Clients make use of this code by first calling
29 /// CrashRecoveryContext::Enable(), and then executing unsafe operations via a
30 /// CrashRecoveryContext object. For example:
32 /// void actual_work(void *);
35 /// CrashRecoveryContext CRC;
37 /// if (!CRC.RunSafely(actual_work, 0)) {
38 /// ... a crash was detected, report error to user ...
41 /// ... no crash was detected ...
44 /// Crash recovery contexts may not be nested.
45 class CrashRecoveryContext {
47 CrashRecoveryContextCleanup *head;
50 CrashRecoveryContext() : Impl(0), head(0) {}
51 ~CrashRecoveryContext();
53 void registerCleanup(CrashRecoveryContextCleanup *cleanup);
54 void unregisterCleanup(CrashRecoveryContextCleanup *cleanup);
56 /// \brief Enable crash recovery.
59 /// \brief Disable crash recovery.
60 static void Disable();
62 /// \brief Return the active context, if the code is currently executing in a
63 /// thread which is in a protected context.
64 static CrashRecoveryContext *GetCurrent();
66 /// \brief Execute the provide callback function (with the given arguments) in
67 /// a protected context.
69 /// \return True if the function completed successfully, and false if the
70 /// function crashed (or HandleCrash was called explicitly). Clients should
71 /// make as little assumptions as possible about the program state when
72 /// RunSafely has returned false. Clients can use getBacktrace() to retrieve
73 /// the backtrace of the crash on failures.
74 bool RunSafely(void (*Fn)(void*), void *UserData);
76 /// \brief Execute the provide callback function (with the given arguments) in
77 /// a protected context which is run in another thread (optionally with a
78 /// requested stack size).
80 /// See RunSafely() and llvm_execute_on_thread().
81 bool RunSafelyOnThread(void (*Fn)(void*), void *UserData,
82 unsigned RequestedStackSize = 0);
84 /// \brief Explicitly trigger a crash recovery in the current process, and
85 /// return failure from RunSafely(). This function does not return.
88 /// \brief Return a string containing the backtrace where the crash was
89 /// detected; or empty if the backtrace wasn't recovered.
91 /// This function is only valid when a crash has been detected (i.e.,
92 /// RunSafely() has returned false.
93 const std::string &getBacktrace() const;
96 class CrashRecoveryContextCleanup {
99 enum ProvidedCleanups { DeleteCleanup, DestructorCleanup };
101 CrashRecoveryContextCleanup() : cleanupFired(false) {}
102 virtual ~CrashRecoveryContextCleanup();
103 virtual void recoverResources() = 0;
105 template <typename T> static CrashRecoveryContextCleanup *create(T *,
106 ProvidedCleanups cleanupKind =
107 CrashRecoveryContextCleanup::DeleteCleanup);
110 friend class CrashRecoveryContext;
111 CrashRecoveryContextCleanup *prev, *next;
114 template <typename T>
115 class CrashRecoveryContextDestructorCleanup
116 : public CrashRecoveryContextCleanup
120 CrashRecoveryContextDestructorCleanup(T *resource) : resource(resource) {}
121 virtual void recoverResources() {
126 template <typename T>
127 class CrashRecoveryContextDeleteCleanup
128 : public CrashRecoveryContextCleanup
132 CrashRecoveryContextDeleteCleanup(T *resource) : resource(resource) {}
133 virtual void recoverResources() {
138 template <typename T>
139 struct CrashRecoveryContextTrait {
140 static inline CrashRecoveryContextCleanup *
141 createCleanup(T *resource,
142 CrashRecoveryContextCleanup::ProvidedCleanups cleanup) {
144 case CrashRecoveryContextCleanup::DeleteCleanup:
145 return new CrashRecoveryContextDeleteCleanup<T>(resource);
146 case CrashRecoveryContextCleanup::DestructorCleanup:
147 return new CrashRecoveryContextDestructorCleanup<T>(resource);
154 inline CrashRecoveryContextCleanup*
155 CrashRecoveryContextCleanup::create(T *x,
156 CrashRecoveryContextCleanup::ProvidedCleanups cleanupKind) {
157 return CrashRecoveryContext::GetCurrent() ?
158 CrashRecoveryContextTrait<T>::createCleanup(x, cleanupKind) :
162 class CrashRecoveryContextCleanupRegistrar {
163 CrashRecoveryContext *context;
164 CrashRecoveryContextCleanup *cleanup;
166 CrashRecoveryContextCleanupRegistrar(CrashRecoveryContextCleanup *cleanup)
167 : context(CrashRecoveryContext::GetCurrent()),
170 if (context && cleanup)
171 context->registerCleanup(cleanup);
173 ~CrashRecoveryContextCleanupRegistrar() {
174 if (cleanup && !cleanup->cleanupFired) {
176 context->unregisterCleanup(cleanup);