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 Return true if the current thread is recovering from a
68 static bool isRecoveringFromCrash();
70 /// \brief Execute the provide callback function (with the given arguments) in
71 /// a protected context.
73 /// \return True if the function completed successfully, and false if the
74 /// function crashed (or HandleCrash was called explicitly). Clients should
75 /// make as little assumptions as possible about the program state when
76 /// RunSafely has returned false. Clients can use getBacktrace() to retrieve
77 /// the backtrace of the crash on failures.
78 bool RunSafely(void (*Fn)(void*), void *UserData);
80 /// \brief Execute the provide callback function (with the given arguments) in
81 /// a protected context which is run in another thread (optionally with a
82 /// requested stack size).
84 /// See RunSafely() and llvm_execute_on_thread().
85 bool RunSafelyOnThread(void (*Fn)(void*), void *UserData,
86 unsigned RequestedStackSize = 0);
88 /// \brief Explicitly trigger a crash recovery in the current process, and
89 /// return failure from RunSafely(). This function does not return.
92 /// \brief Return a string containing the backtrace where the crash was
93 /// detected; or empty if the backtrace wasn't recovered.
95 /// This function is only valid when a crash has been detected (i.e.,
96 /// RunSafely() has returned false.
97 const std::string &getBacktrace() const;
100 class CrashRecoveryContextCleanup {
103 enum ProvidedCleanups { DeleteCleanup, DestructorCleanup };
105 CrashRecoveryContextCleanup() : cleanupFired(false) {}
106 virtual ~CrashRecoveryContextCleanup();
107 virtual void recoverResources() = 0;
109 template <typename T> static CrashRecoveryContextCleanup *create(T *,
110 ProvidedCleanups cleanupKind =
111 CrashRecoveryContextCleanup::DeleteCleanup);
114 friend class CrashRecoveryContext;
115 CrashRecoveryContextCleanup *prev, *next;
118 template <typename T>
119 class CrashRecoveryContextDestructorCleanup
120 : public CrashRecoveryContextCleanup
124 CrashRecoveryContextDestructorCleanup(T *resource) : resource(resource) {}
125 virtual void recoverResources() {
130 template <typename T>
131 class CrashRecoveryContextDeleteCleanup
132 : public CrashRecoveryContextCleanup
136 CrashRecoveryContextDeleteCleanup(T *resource) : resource(resource) {}
137 virtual void recoverResources() {
142 template <typename T>
143 struct CrashRecoveryContextTrait {
144 static inline CrashRecoveryContextCleanup *
145 createCleanup(T *resource,
146 CrashRecoveryContextCleanup::ProvidedCleanups cleanup) {
148 case CrashRecoveryContextCleanup::DeleteCleanup:
149 return new CrashRecoveryContextDeleteCleanup<T>(resource);
150 case CrashRecoveryContextCleanup::DestructorCleanup:
151 return new CrashRecoveryContextDestructorCleanup<T>(resource);
158 inline CrashRecoveryContextCleanup*
159 CrashRecoveryContextCleanup::create(T *x,
160 CrashRecoveryContextCleanup::ProvidedCleanups cleanupKind) {
161 return CrashRecoveryContext::GetCurrent() ?
162 CrashRecoveryContextTrait<T>::createCleanup(x, cleanupKind) :
166 class CrashRecoveryContextCleanupRegistrar {
167 CrashRecoveryContext *context;
168 CrashRecoveryContextCleanup *cleanup;
170 CrashRecoveryContextCleanupRegistrar(CrashRecoveryContextCleanup *cleanup)
171 : context(CrashRecoveryContext::GetCurrent()),
174 if (context && cleanup)
175 context->registerCleanup(cleanup);
177 ~CrashRecoveryContextCleanupRegistrar() {
178 if (cleanup && !cleanup->cleanupFired) {
180 context->unregisterCleanup(cleanup);