LLVM  12.0.0git
Public Member Functions | Static Public Member Functions | Public Attributes | List of all members
llvm::CrashRecoveryContext Class Reference

Crash recovery helper object. More...

#include "llvm/Support/CrashRecoveryContext.h"

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Public Member Functions

 CrashRecoveryContext ()
 
 ~CrashRecoveryContext ()
 
void registerCleanup (CrashRecoveryContextCleanup *cleanup)
 Register cleanup handler, which is used when the recovery context is finished. More...
 
void unregisterCleanup (CrashRecoveryContextCleanup *cleanup)
 
bool RunSafely (function_ref< void()> Fn)
 Execute the provided callback function (with the given arguments) in a protected context. More...
 
bool RunSafely (void(*Fn)(void *), void *UserData)
 
bool RunSafelyOnThread (function_ref< void()>, unsigned RequestedStackSize=0)
 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). More...
 
bool RunSafelyOnThread (void(*Fn)(void *), void *UserData, unsigned RequestedStackSize=0)
 
LLVM_ATTRIBUTE_NORETURN void HandleExit (int RetCode)
 Explicitly trigger a crash recovery in the current process, and return failure from RunSafely(). More...
 

Static Public Member Functions

static void Enable ()
 Enable crash recovery. More...
 
static void Disable ()
 Disable crash recovery. More...
 
static CrashRecoveryContextGetCurrent ()
 Return the active context, if the code is currently executing in a thread which is in a protected context. More...
 
static bool isRecoveringFromCrash ()
 Return true if the current thread is recovering from a crash. More...
 
static bool throwIfCrash (int RetCode)
 Throw again a signal or an exception, after it was catched once by a CrashRecoveryContext. More...
 

Public Attributes

int RetCode = 0
 In case of a crash, this is the crash identifier. More...
 
bool DumpStackAndCleanupOnFailure = false
 Selects whether handling of failures should be done in the same way as for regular crashes. More...
 

Detailed Description

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() {
if (!CRC.RunSafely(actual_work, 0)) {
... a crash was detected, report error to user ...
}
... no crash was detected ...
}

To assist recovery the class allows specifying set of actions that will be executed in any case, whether crash occurs or not. These actions may be used to reclaim resources in the case of crash.

Definition at line 46 of file CrashRecoveryContext.h.

Constructor & Destructor Documentation

◆ CrashRecoveryContext()

CrashRecoveryContext::CrashRecoveryContext ( )

Definition at line 98 of file CrashRecoveryContext.cpp.

References llvm::sys::DisableSystemDialogsOnCrash().

◆ ~CrashRecoveryContext()

CrashRecoveryContext::~CrashRecoveryContext ( )

Member Function Documentation

◆ Disable()

void CrashRecoveryContext::Disable ( )
static

Disable crash recovery.

Definition at line 147 of file CrashRecoveryContext.cpp.

References gCrashRecoveryContextMutex, gCrashRecoveryEnabled, and uninstallExceptionOrSignalHandlers().

Referenced by CrashRecoverySignalHandler().

◆ Enable()

void CrashRecoveryContext::Enable ( )
static

Enable crash recovery.

Definition at line 138 of file CrashRecoveryContext.cpp.

References gCrashRecoveryContextMutex, gCrashRecoveryEnabled, and installExceptionOrSignalHandlers().

◆ GetCurrent()

CrashRecoveryContext * CrashRecoveryContext::GetCurrent ( )
static

Return the active context, if the code is currently executing in a thread which is in a protected context.

Definition at line 127 of file CrashRecoveryContext.cpp.

References gCrashRecoveryEnabled.

Referenced by llvm::CrashRecoveryContextCleanupBase< CrashRecoveryContextDestructorCleanup< T >, T >::create(), and llvm::sys::Process::Exit().

◆ HandleExit()

LLVM_ATTRIBUTE_NORETURN void CrashRecoveryContext::HandleExit ( int  RetCode)

Explicitly trigger a crash recovery in the current process, and return failure from RunSafely().

This function does not return.

Definition at line 431 of file CrashRecoveryContext.cpp.

References assert(), llvm_unreachable, and RetCode.

◆ isRecoveringFromCrash()

bool CrashRecoveryContext::isRecoveringFromCrash ( )
static

Return true if the current thread is recovering from a crash.

Definition at line 123 of file CrashRecoveryContext.cpp.

References tlIsRecoveringFromCrash.

◆ registerCleanup()

void CrashRecoveryContext::registerCleanup ( CrashRecoveryContextCleanup cleanup)

Register cleanup handler, which is used when the recovery context is finished.

The recovery context owns the handler.

Definition at line 155 of file CrashRecoveryContext.cpp.

References cleanup().

Referenced by llvm::CrashRecoveryContextCleanupRegistrar< T, Cleanup >::CrashRecoveryContextCleanupRegistrar().

◆ RunSafely() [1/2]

bool CrashRecoveryContext::RunSafely ( function_ref< void()>  Fn)

Execute the provided callback function (with the given arguments) in a protected context.

Returns
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.

Definition at line 411 of file CrashRecoveryContext.cpp.

References assert(), and gCrashRecoveryEnabled.

Referenced by RunSafely().

◆ RunSafely() [2/2]

bool llvm::CrashRecoveryContext::RunSafely ( void(*)(void *)  Fn,
void *  UserData 
)
inline

Definition at line 82 of file CrashRecoveryContext.h.

References RunSafely().

◆ RunSafelyOnThread() [1/2]

bool CrashRecoveryContext::RunSafelyOnThread ( function_ref< void()>  Fn,
unsigned  RequestedStackSize = 0 
)

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().

On Darwin, if PRIO_DARWIN_BG is set on the calling thread, it will be propagated to the new thread as well.

Definition at line 499 of file CrashRecoveryContext.cpp.

References hasThreadBackgroundPriority(), Info, llvm::llvm_execute_on_thread(), llvm::None, and RunSafelyOnThread_Dispatch().

Referenced by RunSafelyOnThread().

◆ RunSafelyOnThread() [2/2]

bool llvm::CrashRecoveryContext::RunSafelyOnThread ( void(*)(void *)  Fn,
void *  UserData,
unsigned  RequestedStackSize = 0 
)
inline

Definition at line 95 of file CrashRecoveryContext.h.

References RunSafelyOnThread().

◆ throwIfCrash()

bool CrashRecoveryContext::throwIfCrash ( int  RetCode)
static

Throw again a signal or an exception, after it was catched once by a CrashRecoveryContext.

Definition at line 445 of file CrashRecoveryContext.cpp.

References llvm::tgtok::Code, RetCode, and llvm::sys::unregisterHandlers().

◆ unregisterCleanup()

void CrashRecoveryContext::unregisterCleanup ( CrashRecoveryContextCleanup cleanup)

Member Data Documentation

◆ DumpStackAndCleanupOnFailure

bool llvm::CrashRecoveryContext::DumpStackAndCleanupOnFailure = false

Selects whether handling of failures should be done in the same way as for regular crashes.

When this is active, a crash would print the callstack, clean-up any temporary files and create a coredump/minidump.

Definition at line 115 of file CrashRecoveryContext.h.

◆ RetCode

int llvm::CrashRecoveryContext::RetCode = 0

In case of a crash, this is the crash identifier.

Definition at line 110 of file CrashRecoveryContext.h.

Referenced by HandleExit(), and throwIfCrash().


The documentation for this class was generated from the following files: