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Sooooo many of these had incorrect or strange main module includes. I have manually inspected all of these, and fixed the main module include to be the nearest plausible thing I could find. If you own or care about any of these source files, I encourage you to take some time and check that these edits were sensible. I can't have broken anything (I strictly added headers, and reordered them, never removed), but they may not be the headers you'd really like to identify as containing the API being implemented. Many forward declarations and missing includes were added to a header files to allow them to parse cleanly when included first. The main module rule does in fact have its merits. =] git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
347 lines
10 KiB
C++
347 lines
10 KiB
C++
//===--- CrashRecoveryContext.cpp - Crash Recovery ------------------------===//
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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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#include "llvm/Support/CrashRecoveryContext.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Config/config.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/Mutex.h"
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#include "llvm/Support/ThreadLocal.h"
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#include <cstdio>
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#include <setjmp.h>
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using namespace llvm;
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namespace {
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struct CrashRecoveryContextImpl;
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static sys::ThreadLocal<const CrashRecoveryContextImpl> CurrentContext;
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struct CrashRecoveryContextImpl {
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CrashRecoveryContext *CRC;
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std::string Backtrace;
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::jmp_buf JumpBuffer;
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volatile unsigned Failed : 1;
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public:
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CrashRecoveryContextImpl(CrashRecoveryContext *CRC) : CRC(CRC),
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Failed(false) {
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CurrentContext.set(this);
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}
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~CrashRecoveryContextImpl() {
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CurrentContext.erase();
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}
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void HandleCrash() {
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// Eliminate the current context entry, to avoid re-entering in case the
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// cleanup code crashes.
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CurrentContext.erase();
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assert(!Failed && "Crash recovery context already failed!");
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Failed = true;
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// FIXME: Stash the backtrace.
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// Jump back to the RunSafely we were called under.
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longjmp(JumpBuffer, 1);
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}
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};
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}
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static sys::Mutex gCrashRecoveryContexMutex;
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static bool gCrashRecoveryEnabled = false;
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static sys::ThreadLocal<const CrashRecoveryContextCleanup>
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tlIsRecoveringFromCrash;
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CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup() {}
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CrashRecoveryContext::~CrashRecoveryContext() {
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// Reclaim registered resources.
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CrashRecoveryContextCleanup *i = head;
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tlIsRecoveringFromCrash.set(head);
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while (i) {
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CrashRecoveryContextCleanup *tmp = i;
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i = tmp->next;
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tmp->cleanupFired = true;
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tmp->recoverResources();
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delete tmp;
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}
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tlIsRecoveringFromCrash.erase();
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CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
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delete CRCI;
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}
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bool CrashRecoveryContext::isRecoveringFromCrash() {
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return tlIsRecoveringFromCrash.get() != 0;
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}
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CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
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if (!gCrashRecoveryEnabled)
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return 0;
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const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
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if (!CRCI)
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return 0;
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return CRCI->CRC;
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}
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void CrashRecoveryContext::registerCleanup(CrashRecoveryContextCleanup *cleanup)
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{
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if (!cleanup)
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return;
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if (head)
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head->prev = cleanup;
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cleanup->next = head;
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head = cleanup;
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}
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void
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CrashRecoveryContext::unregisterCleanup(CrashRecoveryContextCleanup *cleanup) {
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if (!cleanup)
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return;
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if (cleanup == head) {
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head = cleanup->next;
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if (head)
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head->prev = 0;
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}
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else {
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cleanup->prev->next = cleanup->next;
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if (cleanup->next)
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cleanup->next->prev = cleanup->prev;
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}
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delete cleanup;
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}
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#ifdef LLVM_ON_WIN32
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#include "Windows/Windows.h"
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// On Windows, we can make use of vectored exception handling to
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// catch most crashing situations. Note that this does mean
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// we will be alerted of exceptions *before* structured exception
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// handling has the opportunity to catch it. But that isn't likely
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// to cause problems because nowhere in the project is SEH being
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// used.
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//
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// Vectored exception handling is built on top of SEH, and so it
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// works on a per-thread basis.
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//
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// The vectored exception handler functionality was added in Windows
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// XP, so if support for older versions of Windows is required,
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// it will have to be added.
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//
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// If we want to support as far back as Win2k, we could use the
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// SetUnhandledExceptionFilter API, but there's a risk of that
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// being entirely overwritten (it's not a chain).
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static LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo)
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{
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// Lookup the current thread local recovery object.
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const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
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if (!CRCI) {
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// Something has gone horribly wrong, so let's just tell everyone
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// to keep searching
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CrashRecoveryContext::Disable();
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return EXCEPTION_CONTINUE_SEARCH;
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}
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// TODO: We can capture the stack backtrace here and store it on the
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// implementation if we so choose.
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// Handle the crash
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const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
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// Note that we don't actually get here because HandleCrash calls
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// longjmp, which means the HandleCrash function never returns.
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llvm_unreachable("Handled the crash, should have longjmp'ed out of here");
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}
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// Because the Enable and Disable calls are static, it means that
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// there may not actually be an Impl available, or even a current
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// CrashRecoveryContext at all. So we make use of a thread-local
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// exception table. The handles contained in here will either be
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// non-NULL, valid VEH handles, or NULL.
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static sys::ThreadLocal<const void> sCurrentExceptionHandle;
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void CrashRecoveryContext::Enable() {
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sys::ScopedLock L(gCrashRecoveryContexMutex);
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if (gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = true;
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// We can set up vectored exception handling now. We will install our
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// handler as the front of the list, though there's no assurances that
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// it will remain at the front (another call could install itself before
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// our handler). This 1) isn't likely, and 2) shouldn't cause problems.
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PVOID handle = ::AddVectoredExceptionHandler(1, ExceptionHandler);
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sCurrentExceptionHandle.set(handle);
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}
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void CrashRecoveryContext::Disable() {
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sys::ScopedLock L(gCrashRecoveryContexMutex);
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if (!gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = false;
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PVOID currentHandle = const_cast<PVOID>(sCurrentExceptionHandle.get());
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if (currentHandle) {
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// Now we can remove the vectored exception handler from the chain
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::RemoveVectoredExceptionHandler(currentHandle);
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// Reset the handle in our thread-local set.
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sCurrentExceptionHandle.set(NULL);
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}
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}
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#else
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// Generic POSIX implementation.
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//
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// This implementation relies on synchronous signals being delivered to the
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// current thread. We use a thread local object to keep track of the active
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// crash recovery context, and install signal handlers to invoke HandleCrash on
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// the active object.
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//
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// This implementation does not to attempt to chain signal handlers in any
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// reliable fashion -- if we get a signal outside of a crash recovery context we
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// simply disable crash recovery and raise the signal again.
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#include <signal.h>
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static const int Signals[] = { SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGSEGV, SIGTRAP };
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static const unsigned NumSignals = sizeof(Signals) / sizeof(Signals[0]);
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static struct sigaction PrevActions[NumSignals];
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static void CrashRecoverySignalHandler(int Signal) {
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// Lookup the current thread local recovery object.
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const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
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if (!CRCI) {
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// We didn't find a crash recovery context -- this means either we got a
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// signal on a thread we didn't expect it on, the application got a signal
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// outside of a crash recovery context, or something else went horribly
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// wrong.
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//
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// Disable crash recovery and raise the signal again. The assumption here is
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// that the enclosing application will terminate soon, and we won't want to
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// attempt crash recovery again.
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//
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// This call of Disable isn't thread safe, but it doesn't actually matter.
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CrashRecoveryContext::Disable();
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raise(Signal);
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// The signal will be thrown once the signal mask is restored.
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return;
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}
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// Unblock the signal we received.
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sigset_t SigMask;
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sigemptyset(&SigMask);
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sigaddset(&SigMask, Signal);
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sigprocmask(SIG_UNBLOCK, &SigMask, 0);
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if (CRCI)
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const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
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}
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void CrashRecoveryContext::Enable() {
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sys::ScopedLock L(gCrashRecoveryContexMutex);
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if (gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = true;
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// Setup the signal handler.
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struct sigaction Handler;
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Handler.sa_handler = CrashRecoverySignalHandler;
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Handler.sa_flags = 0;
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sigemptyset(&Handler.sa_mask);
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for (unsigned i = 0; i != NumSignals; ++i) {
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sigaction(Signals[i], &Handler, &PrevActions[i]);
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}
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}
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void CrashRecoveryContext::Disable() {
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sys::ScopedLock L(gCrashRecoveryContexMutex);
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if (!gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = false;
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// Restore the previous signal handlers.
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for (unsigned i = 0; i != NumSignals; ++i)
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sigaction(Signals[i], &PrevActions[i], 0);
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}
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#endif
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bool CrashRecoveryContext::RunSafely(void (*Fn)(void*), void *UserData) {
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// If crash recovery is disabled, do nothing.
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if (gCrashRecoveryEnabled) {
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assert(!Impl && "Crash recovery context already initialized!");
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CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this);
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Impl = CRCI;
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if (setjmp(CRCI->JumpBuffer) != 0) {
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return false;
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}
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}
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Fn(UserData);
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return true;
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}
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void CrashRecoveryContext::HandleCrash() {
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CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
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assert(CRCI && "Crash recovery context never initialized!");
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CRCI->HandleCrash();
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}
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const std::string &CrashRecoveryContext::getBacktrace() const {
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CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *) Impl;
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assert(CRC && "Crash recovery context never initialized!");
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assert(CRC->Failed && "No crash was detected!");
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return CRC->Backtrace;
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}
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//
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namespace {
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struct RunSafelyOnThreadInfo {
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void (*UserFn)(void*);
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void *UserData;
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CrashRecoveryContext *CRC;
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bool Result;
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};
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}
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static void RunSafelyOnThread_Dispatch(void *UserData) {
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RunSafelyOnThreadInfo *Info =
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reinterpret_cast<RunSafelyOnThreadInfo*>(UserData);
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Info->Result = Info->CRC->RunSafely(Info->UserFn, Info->UserData);
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}
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bool CrashRecoveryContext::RunSafelyOnThread(void (*Fn)(void*), void *UserData,
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unsigned RequestedStackSize) {
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RunSafelyOnThreadInfo Info = { Fn, UserData, this, false };
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llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
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return Info.Result;
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}
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