CrashRecoveryContext.cpp [plain text]
#include "llvm/Support/CrashRecoveryContext.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/ThreadLocal.h"
#include "llvm/Support/ErrorHandling.h"
#include <setjmp.h>
#include <cstdio>
using namespace llvm;
namespace {
struct CrashRecoveryContextImpl;
static sys::ThreadLocal<const CrashRecoveryContextImpl> CurrentContext;
struct CrashRecoveryContextImpl {
CrashRecoveryContext *CRC;
std::string Backtrace;
::jmp_buf JumpBuffer;
volatile unsigned Failed : 1;
public:
CrashRecoveryContextImpl(CrashRecoveryContext *CRC) : CRC(CRC),
Failed(false) {
CurrentContext.set(this);
}
~CrashRecoveryContextImpl() {
CurrentContext.erase();
}
void HandleCrash() {
CurrentContext.erase();
assert(!Failed && "Crash recovery context already failed!");
Failed = true;
longjmp(JumpBuffer, 1);
}
};
}
static sys::Mutex gCrashRecoveryContexMutex;
static bool gCrashRecoveryEnabled = false;
static sys::ThreadLocal<const CrashRecoveryContextCleanup>
tlIsRecoveringFromCrash;
CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup() {}
CrashRecoveryContext::~CrashRecoveryContext() {
CrashRecoveryContextCleanup *i = head;
tlIsRecoveringFromCrash.set(head);
while (i) {
CrashRecoveryContextCleanup *tmp = i;
i = tmp->next;
tmp->cleanupFired = true;
tmp->recoverResources();
delete tmp;
}
tlIsRecoveringFromCrash.erase();
CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
delete CRCI;
}
bool CrashRecoveryContext::isRecoveringFromCrash() {
return tlIsRecoveringFromCrash.get() != 0;
}
CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
if (!gCrashRecoveryEnabled)
return 0;
const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
if (!CRCI)
return 0;
return CRCI->CRC;
}
void CrashRecoveryContext::registerCleanup(CrashRecoveryContextCleanup *cleanup)
{
if (!cleanup)
return;
if (head)
head->prev = cleanup;
cleanup->next = head;
head = cleanup;
}
void
CrashRecoveryContext::unregisterCleanup(CrashRecoveryContextCleanup *cleanup) {
if (!cleanup)
return;
if (cleanup == head) {
head = cleanup->next;
if (head)
head->prev = 0;
}
else {
cleanup->prev->next = cleanup->next;
if (cleanup->next)
cleanup->next->prev = cleanup->prev;
}
delete cleanup;
}
#ifdef LLVM_ON_WIN32
#include "Windows/Windows.h"
static LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo)
{
const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
if (!CRCI) {
CrashRecoveryContext::Disable();
return EXCEPTION_CONTINUE_SEARCH;
}
const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
llvm_unreachable("Handled the crash, should have longjmp'ed out of here");
}
static sys::ThreadLocal<const void> sCurrentExceptionHandle;
void CrashRecoveryContext::Enable() {
sys::ScopedLock L(gCrashRecoveryContexMutex);
if (gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = true;
PVOID handle = ::AddVectoredExceptionHandler(1, ExceptionHandler);
sCurrentExceptionHandle.set(handle);
}
void CrashRecoveryContext::Disable() {
sys::ScopedLock L(gCrashRecoveryContexMutex);
if (!gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = false;
PVOID currentHandle = const_cast<PVOID>(sCurrentExceptionHandle.get());
if (currentHandle) {
::RemoveVectoredExceptionHandler(currentHandle);
sCurrentExceptionHandle.set(NULL);
}
}
#else
#include <signal.h>
static int Signals[] = { SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGSEGV, SIGTRAP };
static const unsigned NumSignals = sizeof(Signals) / sizeof(Signals[0]);
static struct sigaction PrevActions[NumSignals];
static void CrashRecoverySignalHandler(int Signal) {
const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
if (!CRCI) {
CrashRecoveryContext::Disable();
raise(Signal);
return;
}
sigset_t SigMask;
sigemptyset(&SigMask);
sigaddset(&SigMask, Signal);
sigprocmask(SIG_UNBLOCK, &SigMask, 0);
if (CRCI)
const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
}
void CrashRecoveryContext::Enable() {
sys::ScopedLock L(gCrashRecoveryContexMutex);
if (gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = true;
struct sigaction Handler;
Handler.sa_handler = CrashRecoverySignalHandler;
Handler.sa_flags = 0;
sigemptyset(&Handler.sa_mask);
for (unsigned i = 0; i != NumSignals; ++i) {
sigaction(Signals[i], &Handler, &PrevActions[i]);
}
}
void CrashRecoveryContext::Disable() {
sys::ScopedLock L(gCrashRecoveryContexMutex);
if (!gCrashRecoveryEnabled)
return;
gCrashRecoveryEnabled = false;
for (unsigned i = 0; i != NumSignals; ++i)
sigaction(Signals[i], &PrevActions[i], 0);
}
#endif
bool CrashRecoveryContext::RunSafely(void (*Fn)(void*), void *UserData) {
if (gCrashRecoveryEnabled) {
assert(!Impl && "Crash recovery context already initialized!");
CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this);
Impl = CRCI;
if (setjmp(CRCI->JumpBuffer) != 0) {
return false;
}
}
Fn(UserData);
return true;
}
void CrashRecoveryContext::HandleCrash() {
CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
assert(CRCI && "Crash recovery context never initialized!");
CRCI->HandleCrash();
}
const std::string &CrashRecoveryContext::getBacktrace() const {
CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *) Impl;
assert(CRC && "Crash recovery context never initialized!");
assert(CRC->Failed && "No crash was detected!");
return CRC->Backtrace;
}
namespace {
struct RunSafelyOnThreadInfo {
void (*UserFn)(void*);
void *UserData;
CrashRecoveryContext *CRC;
bool Result;
};
}
static void RunSafelyOnThread_Dispatch(void *UserData) {
RunSafelyOnThreadInfo *Info =
reinterpret_cast<RunSafelyOnThreadInfo*>(UserData);
Info->Result = Info->CRC->RunSafely(Info->UserFn, Info->UserData);
}
bool CrashRecoveryContext::RunSafelyOnThread(void (*Fn)(void*), void *UserData,
unsigned RequestedStackSize) {
RunSafelyOnThreadInfo Info = { Fn, UserData, this, false };
llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
return Info.Result;
}