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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109872 91177308-0d34-0410-b5e6-96231b3b80d8
181 lines
4.8 KiB
C++
181 lines
4.8 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/System/ThreadLocal.h"
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#include <setjmp.h>
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#include <cstdio>
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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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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() : 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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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 bool gCrashRecoveryEnabled = false;
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CrashRecoveryContext::~CrashRecoveryContext() {
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CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
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delete CRCI;
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}
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#ifdef LLVM_ON_WIN32
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// FIXME: No real Win32 implementation currently.
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void CrashRecoveryContext::Enable() {
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if (gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = true;
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}
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void CrashRecoveryContext::Disable() {
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if (!gCrashRecoveryEnabled)
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return;
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gCrashRecoveryEnabled = false;
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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 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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}
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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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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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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;
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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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