diff options
Diffstat (limited to 'contrib/llvm/lib/Support/CrashRecoveryContext.cpp')
| -rw-r--r-- | contrib/llvm/lib/Support/CrashRecoveryContext.cpp | 411 |
1 files changed, 0 insertions, 411 deletions
diff --git a/contrib/llvm/lib/Support/CrashRecoveryContext.cpp b/contrib/llvm/lib/Support/CrashRecoveryContext.cpp deleted file mode 100644 index c2459256f8fe..000000000000 --- a/contrib/llvm/lib/Support/CrashRecoveryContext.cpp +++ /dev/null @@ -1,411 +0,0 @@ -//===--- CrashRecoveryContext.cpp - Crash Recovery ------------------------===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// - -#include "llvm/Support/CrashRecoveryContext.h" -#include "llvm/Config/llvm-config.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/ManagedStatic.h" -#include "llvm/Support/Mutex.h" -#include "llvm/Support/ThreadLocal.h" -#include <setjmp.h> -using namespace llvm; - -namespace { - -struct CrashRecoveryContextImpl; - -static ManagedStatic< - sys::ThreadLocal<const CrashRecoveryContextImpl> > CurrentContext; - -struct CrashRecoveryContextImpl { - // When threads are disabled, this links up all active - // CrashRecoveryContextImpls. When threads are enabled there's one thread - // per CrashRecoveryContext and CurrentContext is a thread-local, so only one - // CrashRecoveryContextImpl is active per thread and this is always null. - const CrashRecoveryContextImpl *Next; - - CrashRecoveryContext *CRC; - ::jmp_buf JumpBuffer; - volatile unsigned Failed : 1; - unsigned SwitchedThread : 1; - -public: - CrashRecoveryContextImpl(CrashRecoveryContext *CRC) : CRC(CRC), - Failed(false), - SwitchedThread(false) { - Next = CurrentContext->get(); - CurrentContext->set(this); - } - ~CrashRecoveryContextImpl() { - if (!SwitchedThread) - CurrentContext->set(Next); - } - - /// Called when the separate crash-recovery thread was finished, to - /// indicate that we don't need to clear the thread-local CurrentContext. - void setSwitchedThread() { -#if defined(LLVM_ENABLE_THREADS) && LLVM_ENABLE_THREADS != 0 - SwitchedThread = true; -#endif - } - - void HandleCrash() { - // Eliminate the current context entry, to avoid re-entering in case the - // cleanup code crashes. - CurrentContext->set(Next); - - assert(!Failed && "Crash recovery context already failed!"); - Failed = true; - - // FIXME: Stash the backtrace. - - // Jump back to the RunSafely we were called under. - longjmp(JumpBuffer, 1); - } -}; - -} - -static ManagedStatic<sys::Mutex> gCrashRecoveryContextMutex; -static bool gCrashRecoveryEnabled = false; - -static ManagedStatic<sys::ThreadLocal<const CrashRecoveryContext>> - tlIsRecoveringFromCrash; - -static void installExceptionOrSignalHandlers(); -static void uninstallExceptionOrSignalHandlers(); - -CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup() {} - -CrashRecoveryContext::~CrashRecoveryContext() { - // Reclaim registered resources. - CrashRecoveryContextCleanup *i = head; - const CrashRecoveryContext *PC = tlIsRecoveringFromCrash->get(); - tlIsRecoveringFromCrash->set(this); - while (i) { - CrashRecoveryContextCleanup *tmp = i; - i = tmp->next; - tmp->cleanupFired = true; - tmp->recoverResources(); - delete tmp; - } - tlIsRecoveringFromCrash->set(PC); - - CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl; - delete CRCI; -} - -bool CrashRecoveryContext::isRecoveringFromCrash() { - return tlIsRecoveringFromCrash->get() != nullptr; -} - -CrashRecoveryContext *CrashRecoveryContext::GetCurrent() { - if (!gCrashRecoveryEnabled) - return nullptr; - - const CrashRecoveryContextImpl *CRCI = CurrentContext->get(); - if (!CRCI) - return nullptr; - - return CRCI->CRC; -} - -void CrashRecoveryContext::Enable() { - sys::ScopedLock L(*gCrashRecoveryContextMutex); - // FIXME: Shouldn't this be a refcount or something? - if (gCrashRecoveryEnabled) - return; - gCrashRecoveryEnabled = true; - installExceptionOrSignalHandlers(); -} - -void CrashRecoveryContext::Disable() { - sys::ScopedLock L(*gCrashRecoveryContextMutex); - if (!gCrashRecoveryEnabled) - return; - gCrashRecoveryEnabled = false; - uninstallExceptionOrSignalHandlers(); -} - -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 = nullptr; - } - else { - cleanup->prev->next = cleanup->next; - if (cleanup->next) - cleanup->next->prev = cleanup->prev; - } - delete cleanup; -} - -#if defined(_MSC_VER) -// If _MSC_VER is defined, we must have SEH. Use it if it's available. It's way -// better than VEH. Vectored exception handling catches all exceptions happening -// on the thread with installed exception handlers, so it can interfere with -// internal exception handling of other libraries on that thread. SEH works -// exactly as you would expect normal exception handling to work: it only -// catches exceptions if they would bubble out from the stack frame with __try / -// __except. - -static void installExceptionOrSignalHandlers() {} -static void uninstallExceptionOrSignalHandlers() {} - -bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) { - if (!gCrashRecoveryEnabled) { - Fn(); - return true; - } - - bool Result = true; - __try { - Fn(); - } __except (1) { // Catch any exception. - Result = false; - } - return Result; -} - -#else // !_MSC_VER - -#if defined(_WIN32) -// This is a non-MSVC compiler, probably mingw gcc or clang without -// -fms-extensions. Use vectored exception handling (VEH). -// -// On Windows, we can make use of vectored exception handling to catch most -// crashing situations. Note that this does mean we will be alerted of -// exceptions *before* structured exception handling has the opportunity to -// catch it. Unfortunately, this causes problems in practice with other code -// running on threads with LLVM crash recovery contexts, so we would like to -// eventually move away from VEH. -// -// Vectored works on a per-thread basis, which is an advantage over -// SetUnhandledExceptionFilter. SetUnhandledExceptionFilter also doesn't have -// any native support for chaining exception handlers, but VEH allows more than -// one. -// -// The vectored exception handler functionality was added in Windows -// XP, so if support for older versions of Windows is required, -// it will have to be added. - -#include "Windows/WindowsSupport.h" - -static LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo) -{ - // DBG_PRINTEXCEPTION_WIDE_C is not properly defined on all supported - // compilers and platforms, so we define it manually. - constexpr ULONG DbgPrintExceptionWideC = 0x4001000AL; - switch (ExceptionInfo->ExceptionRecord->ExceptionCode) - { - case DBG_PRINTEXCEPTION_C: - case DbgPrintExceptionWideC: - case 0x406D1388: // set debugger thread name - return EXCEPTION_CONTINUE_EXECUTION; - } - - // Lookup the current thread local recovery object. - const CrashRecoveryContextImpl *CRCI = CurrentContext->get(); - - if (!CRCI) { - // Something has gone horribly wrong, so let's just tell everyone - // to keep searching - CrashRecoveryContext::Disable(); - return EXCEPTION_CONTINUE_SEARCH; - } - - // TODO: We can capture the stack backtrace here and store it on the - // implementation if we so choose. - - // Handle the crash - const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash(); - - // Note that we don't actually get here because HandleCrash calls - // longjmp, which means the HandleCrash function never returns. - llvm_unreachable("Handled the crash, should have longjmp'ed out of here"); -} - -// Because the Enable and Disable calls are static, it means that -// there may not actually be an Impl available, or even a current -// CrashRecoveryContext at all. So we make use of a thread-local -// exception table. The handles contained in here will either be -// non-NULL, valid VEH handles, or NULL. -static sys::ThreadLocal<const void> sCurrentExceptionHandle; - -static void installExceptionOrSignalHandlers() { - // We can set up vectored exception handling now. We will install our - // handler as the front of the list, though there's no assurances that - // it will remain at the front (another call could install itself before - // our handler). This 1) isn't likely, and 2) shouldn't cause problems. - PVOID handle = ::AddVectoredExceptionHandler(1, ExceptionHandler); - sCurrentExceptionHandle.set(handle); -} - -static void uninstallExceptionOrSignalHandlers() { - PVOID currentHandle = const_cast<PVOID>(sCurrentExceptionHandle.get()); - if (currentHandle) { - // Now we can remove the vectored exception handler from the chain - ::RemoveVectoredExceptionHandler(currentHandle); - - // Reset the handle in our thread-local set. - sCurrentExceptionHandle.set(NULL); - } -} - -#else // !_WIN32 - -// Generic POSIX implementation. -// -// This implementation relies on synchronous signals being delivered to the -// current thread. We use a thread local object to keep track of the active -// crash recovery context, and install signal handlers to invoke HandleCrash on -// the active object. -// -// This implementation does not to attempt to chain signal handlers in any -// reliable fashion -- if we get a signal outside of a crash recovery context we -// simply disable crash recovery and raise the signal again. - -#include <signal.h> - -static const int Signals[] = - { SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGSEGV, SIGTRAP }; -static const unsigned NumSignals = array_lengthof(Signals); -static struct sigaction PrevActions[NumSignals]; - -static void CrashRecoverySignalHandler(int Signal) { - // Lookup the current thread local recovery object. - const CrashRecoveryContextImpl *CRCI = CurrentContext->get(); - - if (!CRCI) { - // We didn't find a crash recovery context -- this means either we got a - // signal on a thread we didn't expect it on, the application got a signal - // outside of a crash recovery context, or something else went horribly - // wrong. - // - // Disable crash recovery and raise the signal again. The assumption here is - // that the enclosing application will terminate soon, and we won't want to - // attempt crash recovery again. - // - // This call of Disable isn't thread safe, but it doesn't actually matter. - CrashRecoveryContext::Disable(); - raise(Signal); - - // The signal will be thrown once the signal mask is restored. - return; - } - - // Unblock the signal we received. - sigset_t SigMask; - sigemptyset(&SigMask); - sigaddset(&SigMask, Signal); - sigprocmask(SIG_UNBLOCK, &SigMask, nullptr); - - if (CRCI) - const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash(); -} - -static void installExceptionOrSignalHandlers() { - // Setup the signal handler. - 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]); - } -} - -static void uninstallExceptionOrSignalHandlers() { - // Restore the previous signal handlers. - for (unsigned i = 0; i != NumSignals; ++i) - sigaction(Signals[i], &PrevActions[i], nullptr); -} - -#endif // !_WIN32 - -bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) { - // If crash recovery is disabled, do nothing. - if (gCrashRecoveryEnabled) { - assert(!Impl && "Crash recovery context already initialized!"); - CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this); - Impl = CRCI; - - if (setjmp(CRCI->JumpBuffer) != 0) { - return false; - } - } - - Fn(); - return true; -} - -#endif // !_MSC_VER - -void CrashRecoveryContext::HandleCrash() { - CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl; - assert(CRCI && "Crash recovery context never initialized!"); - CRCI->HandleCrash(); -} - -// FIXME: Portability. -static void setThreadBackgroundPriority() { -#ifdef __APPLE__ - setpriority(PRIO_DARWIN_THREAD, 0, PRIO_DARWIN_BG); -#endif -} - -static bool hasThreadBackgroundPriority() { -#ifdef __APPLE__ - return getpriority(PRIO_DARWIN_THREAD, 0) == 1; -#else - return false; -#endif -} - -namespace { -struct RunSafelyOnThreadInfo { - function_ref<void()> Fn; - CrashRecoveryContext *CRC; - bool UseBackgroundPriority; - bool Result; -}; -} - -static void RunSafelyOnThread_Dispatch(void *UserData) { - RunSafelyOnThreadInfo *Info = - reinterpret_cast<RunSafelyOnThreadInfo*>(UserData); - - if (Info->UseBackgroundPriority) - setThreadBackgroundPriority(); - - Info->Result = Info->CRC->RunSafely(Info->Fn); -} -bool CrashRecoveryContext::RunSafelyOnThread(function_ref<void()> Fn, - unsigned RequestedStackSize) { - bool UseBackgroundPriority = hasThreadBackgroundPriority(); - RunSafelyOnThreadInfo Info = { Fn, this, UseBackgroundPriority, false }; - llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize); - if (CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *)Impl) - CRC->setSwitchedThread(); - return Info.Result; -} |