2010-07-28 17:40:20 +02:00
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//===--- CrashRecoveryContext.h - Crash Recovery ----------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
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#define LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
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#include <string>
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namespace llvm {
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class StringRef;
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2011-03-18 03:05:11 +01:00
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class CrashRecoveryContextCleanup;
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2010-07-28 17:40:20 +02:00
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/// \brief Crash recovery helper object.
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///
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/// This class implements support for running operations in a safe context so
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/// that crashes (memory errors, stack overflow, assertion violations) can be
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/// detected and control restored to the crashing thread. Crash detection is
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/// purely "best effort", the exact set of failures which can be recovered from
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/// is platform dependent.
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///
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/// Clients make use of this code by first calling
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/// CrashRecoveryContext::Enable(), and then executing unsafe operations via a
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/// CrashRecoveryContext object. For example:
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///
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/// void actual_work(void *);
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///
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/// void foo() {
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/// CrashRecoveryContext CRC;
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///
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/// if (!CRC.RunSafely(actual_work, 0)) {
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/// ... a crash was detected, report error to user ...
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/// }
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///
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/// ... no crash was detected ...
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/// }
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///
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/// Crash recovery contexts may not be nested.
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class CrashRecoveryContext {
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void *Impl;
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CrashRecoveryContextCleanup *head;
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public:
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CrashRecoveryContext() : Impl(0), head(0) {}
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~CrashRecoveryContext();
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void registerCleanup(CrashRecoveryContextCleanup *cleanup);
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void unregisterCleanup(CrashRecoveryContextCleanup *cleanup);
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2010-07-28 17:40:20 +02:00
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2010-08-18 00:32:34 +02:00
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/// \brief Enable crash recovery.
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static void Enable();
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2010-08-18 00:32:34 +02:00
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/// \brief Disable crash recovery.
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static void Disable();
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2010-08-18 00:32:37 +02:00
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/// \brief Return the active context, if the code is currently executing in a
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/// thread which is in a protected context.
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static CrashRecoveryContext *GetCurrent();
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2011-03-21 19:38:03 +01:00
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/// \brief Return true if the current thread is recovering from a
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/// crash.
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static bool isRecoveringFromCrash();
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/// \brief Execute the provide callback function (with the given arguments) in
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/// a protected context.
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///
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/// \return True if the function completed successfully, and false if the
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/// function crashed (or HandleCrash was called explicitly). Clients should
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/// make as little assumptions as possible about the program state when
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/// RunSafely has returned false. Clients can use getBacktrace() to retrieve
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/// the backtrace of the crash on failures.
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bool RunSafely(void (*Fn)(void*), void *UserData);
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2010-11-05 08:19:09 +01:00
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/// \brief Execute the provide callback function (with the given arguments) in
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/// a protected context which is run in another thread (optionally with a
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/// requested stack size).
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///
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/// See RunSafely() and llvm_execute_on_thread().
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bool RunSafelyOnThread(void (*Fn)(void*), void *UserData,
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unsigned RequestedStackSize = 0);
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2010-07-28 17:40:20 +02:00
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/// \brief Explicitly trigger a crash recovery in the current process, and
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/// return failure from RunSafely(). This function does not return.
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void HandleCrash();
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/// \brief Return a string containing the backtrace where the crash was
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/// detected; or empty if the backtrace wasn't recovered.
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///
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/// This function is only valid when a crash has been detected (i.e.,
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/// RunSafely() has returned false.
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const std::string &getBacktrace() const;
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};
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class CrashRecoveryContextCleanup {
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public:
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bool cleanupFired;
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enum ProvidedCleanups { DeleteCleanup, DestructorCleanup };
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CrashRecoveryContextCleanup() : cleanupFired(false) {}
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virtual ~CrashRecoveryContextCleanup();
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virtual void recoverResources() = 0;
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2011-03-19 01:59:37 +01:00
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template <typename T> static CrashRecoveryContextCleanup *create(T *,
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ProvidedCleanups cleanupKind =
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CrashRecoveryContextCleanup::DeleteCleanup);
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private:
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friend class CrashRecoveryContext;
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CrashRecoveryContextCleanup *prev, *next;
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};
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template <typename T>
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class CrashRecoveryContextDestructorCleanup
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: public CrashRecoveryContextCleanup
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{
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T *resource;
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public:
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CrashRecoveryContextDestructorCleanup(T *resource) : resource(resource) {}
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virtual void recoverResources() {
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resource->~T();
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}
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};
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2011-03-18 04:04:18 +01:00
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template <typename T>
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class CrashRecoveryContextDeleteCleanup
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: public CrashRecoveryContextCleanup
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{
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T *resource;
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public:
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CrashRecoveryContextDeleteCleanup(T *resource) : resource(resource) {}
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virtual void recoverResources() {
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delete resource;
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}
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};
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template <typename T>
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struct CrashRecoveryContextTrait {
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static inline CrashRecoveryContextCleanup *
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createCleanup(T *resource,
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CrashRecoveryContextCleanup::ProvidedCleanups cleanup) {
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switch (cleanup) {
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case CrashRecoveryContextCleanup::DeleteCleanup:
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return new CrashRecoveryContextDeleteCleanup<T>(resource);
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case CrashRecoveryContextCleanup::DestructorCleanup:
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return new CrashRecoveryContextDestructorCleanup<T>(resource);
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}
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return 0;
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}
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};
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template<typename T>
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inline CrashRecoveryContextCleanup*
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CrashRecoveryContextCleanup::create(T *x,
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CrashRecoveryContextCleanup::ProvidedCleanups cleanupKind) {
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return CrashRecoveryContext::GetCurrent() ?
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CrashRecoveryContextTrait<T>::createCleanup(x, cleanupKind) :
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0;
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}
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class CrashRecoveryContextCleanupRegistrar {
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CrashRecoveryContext *context;
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CrashRecoveryContextCleanup *cleanup;
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public:
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CrashRecoveryContextCleanupRegistrar(CrashRecoveryContextCleanup *cleanup)
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: context(CrashRecoveryContext::GetCurrent()),
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cleanup(cleanup)
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{
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if (context && cleanup)
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context->registerCleanup(cleanup);
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}
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~CrashRecoveryContextCleanupRegistrar() {
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if (cleanup && !cleanup->cleanupFired) {
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if (context)
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context->unregisterCleanup(cleanup);
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else
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delete cleanup;
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}
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}
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};
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2010-07-28 17:40:20 +02:00
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}
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#endif
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