llvm::CrashRecoveryContext Class Reference

Crash recovery helper object. More...

#include "llvm/Support/CrashRecoveryContext.h"

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

Static Public Member Functions
static void	Enable ()
	Enable crash recovery.
static void	Disable ()
	Disable crash recovery.
static CrashRecoveryContext *	GetCurrent ()
	Return the active context, if the code is currently executing in a thread which is in a protected context.
static bool	isRecoveringFromCrash ()
	Return true if the current thread is recovering from a crash.
static bool	isCrash (int RetCode)
	Return true if RetCode indicates that a signal or an exception occurred.
static bool	throwIfCrash (int RetCode)
	Throw again a signal or an exception, after it was catched once by a CrashRecoveryContext.

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

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() {
  CrashRecoveryContext CRC;
 
  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 100 of file CrashRecoveryContext.cpp.

References llvm::sys::DisableSystemDialogsOnCrash().

~CrashRecoveryContext()

CrashRecoveryContext::~CrashRecoveryContext

(

)

Definition at line 107 of file CrashRecoveryContext.cpp.

References llvm::CrashRecoveryContextCleanup::cleanupFired, and llvm::CrashRecoveryContextCleanup::recoverResources().

Member Function Documentation

Disable()

void CrashRecoveryContext::Disable ( )

static

Disable crash recovery.

Definition at line 149 of file CrashRecoveryContext.cpp.

References uninstallExceptionOrSignalHandlers().

Referenced by CrashRecoverySignalHandler().

Enable()

void CrashRecoveryContext::Enable ( )

static

Enable crash recovery.

Definition at line 140 of file CrashRecoveryContext.cpp.

References 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 129 of file CrashRecoveryContext.cpp.

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

HandleExit()

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 432 of file CrashRecoveryContext.cpp.

References assert(), llvm_unreachable, and RetCode.

isCrash()

bool CrashRecoveryContext::isCrash ( int  RetCode )

static

Return true if RetCode indicates that a signal or an exception occurred.

Definition at line 449 of file CrashRecoveryContext.cpp.

References RetCode.

Referenced by throwIfCrash().

isRecoveringFromCrash()

bool CrashRecoveryContext::isRecoveringFromCrash ( )

static

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

Definition at line 125 of file CrashRecoveryContext.cpp.

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 157 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 413 of file CrashRecoveryContext.cpp.

References assert().

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().

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 512 of file CrashRecoveryContext.cpp.

References hasThreadBackgroundPriority(), Info, RunSafelyOnThread_Dispatch(), and Thread.

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 467 of file CrashRecoveryContext.cpp.

References isCrash(), RetCode, and llvm::sys::unregisterHandlers().

unregisterCleanup()

void CrashRecoveryContext::unregisterCleanup

(

CrashRecoveryContextCleanup *

cleanup

)

Definition at line 168 of file CrashRecoveryContext.cpp.

References cleanup().

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

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 117 of file CrashRecoveryContext.h.

RetCode

int llvm::CrashRecoveryContext::RetCode = 0

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

Definition at line 112 of file CrashRecoveryContext.h.

Referenced by HandleExit(), isCrash(), and throwIfCrash().

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

• include/llvm/Support/CrashRecoveryContext.h
• lib/Support/CrashRecoveryContext.cpp