aganea created this revision.
aganea added reviewers: hans, rnk, thakis.
Herald added subscribers: llvm-commits, cfe-commits, jfb, arphaman, hiraditya.
Herald added a reviewer: jfb.
Herald added projects: clang, LLVM.
aganea edited the summary of this revision.
Herald added a subscriber: dexonsmith.
This is a support patch for D69825 <https://reviews.llvm.org/D69825>.
It handles an exception in the same way as the global exception handler (same
side-effect, print call stack & cleanup), and can return the exception code.
It enables `CrashRecoveryContext` exceptions by default (instead of disabled
before) - however the exception handlers are lazily installed on the first
creation of a `CrashRecoveryContext`.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D70568
Files:
clang/test/Modules/signal.m
clang/tools/libclang/CIndex.cpp
llvm/include/llvm/Support/CrashRecoveryContext.h
llvm/include/llvm/Support/Signals.h
llvm/lib/Support/CrashRecoveryContext.cpp
llvm/lib/Support/Unix/Signals.inc
llvm/lib/Support/Windows/Signals.inc
Index: llvm/lib/Support/Windows/Signals.inc
===================================================================
--- llvm/lib/Support/Windows/Signals.inc
+++ llvm/lib/Support/Windows/Signals.inc
@@ -521,10 +521,13 @@
extern "C" VOID WINAPI RtlCaptureContext(PCONTEXT ContextRecord);
#endif
-void llvm::sys::PrintStackTrace(raw_ostream &OS) {
- STACKFRAME64 StackFrame = {};
- CONTEXT Context = {};
- ::RtlCaptureContext(&Context);
+static void LocalPrintStackTrace(raw_ostream &OS, PCONTEXT C) {
+ STACKFRAME64 StackFrame{};
+ CONTEXT Context{};
+ if (!C) {
+ ::RtlCaptureContext(&Context);
+ C = &Context;
+ }
#if defined(_M_X64)
StackFrame.AddrPC.Offset = Context.Rip;
StackFrame.AddrStack.Offset = Context.Rsp;
@@ -546,9 +549,12 @@
StackFrame.AddrStack.Mode = AddrModeFlat;
StackFrame.AddrFrame.Mode = AddrModeFlat;
PrintStackTraceForThread(OS, GetCurrentProcess(), GetCurrentThread(),
- StackFrame, &Context);
+ StackFrame, C);
}
+void llvm::sys::PrintStackTrace(raw_ostream &OS) {
+ LocalPrintStackTrace(OS, nullptr);
+}
void llvm::sys::SetInterruptFunction(void (*IF)()) {
RegisterHandler();
@@ -792,6 +798,10 @@
return std::error_code();
}
+signed sys::InvokeExceptionHandler(int &, void *ExceptionInfo) {
+ return LLVMUnhandledExceptionFilter((LPEXCEPTION_POINTERS)ExceptionInfo);
+}
+
static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep) {
Cleanup();
@@ -810,42 +820,9 @@
<< "\n";
}
- // Initialize the STACKFRAME structure.
- STACKFRAME64 StackFrame = {};
-
-#if defined(_M_X64)
- StackFrame.AddrPC.Offset = ep->ContextRecord->Rip;
- StackFrame.AddrPC.Mode = AddrModeFlat;
- StackFrame.AddrStack.Offset = ep->ContextRecord->Rsp;
- StackFrame.AddrStack.Mode = AddrModeFlat;
- StackFrame.AddrFrame.Offset = ep->ContextRecord->Rbp;
- StackFrame.AddrFrame.Mode = AddrModeFlat;
-#elif defined(_M_IX86)
- StackFrame.AddrPC.Offset = ep->ContextRecord->Eip;
- StackFrame.AddrPC.Mode = AddrModeFlat;
- StackFrame.AddrStack.Offset = ep->ContextRecord->Esp;
- StackFrame.AddrStack.Mode = AddrModeFlat;
- StackFrame.AddrFrame.Offset = ep->ContextRecord->Ebp;
- StackFrame.AddrFrame.Mode = AddrModeFlat;
-#elif defined(_M_ARM64) || defined(_M_ARM)
- StackFrame.AddrPC.Offset = ep->ContextRecord->Pc;
- StackFrame.AddrPC.Mode = AddrModeFlat;
- StackFrame.AddrStack.Offset = ep->ContextRecord->Sp;
- StackFrame.AddrStack.Mode = AddrModeFlat;
-#if defined(_M_ARM64)
- StackFrame.AddrFrame.Offset = ep->ContextRecord->Fp;
-#else
- StackFrame.AddrFrame.Offset = ep->ContextRecord->R11;
-#endif
- StackFrame.AddrFrame.Mode = AddrModeFlat;
-#endif
-
- HANDLE hProcess = GetCurrentProcess();
- HANDLE hThread = GetCurrentThread();
- PrintStackTraceForThread(llvm::errs(), hProcess, hThread, StackFrame,
- ep->ContextRecord);
+ LocalPrintStackTrace(llvm::errs(), ep ? ep->ContextRecord : nullptr);
- _exit(ep->ExceptionRecord->ExceptionCode);
+ return EXCEPTION_EXECUTE_HANDLER;
}
static BOOL WINAPI LLVMConsoleCtrlHandler(DWORD dwCtrlType) {
Index: llvm/lib/Support/Unix/Signals.inc
===================================================================
--- llvm/lib/Support/Unix/Signals.inc
+++ llvm/lib/Support/Unix/Signals.inc
@@ -345,6 +345,17 @@
FileToRemoveList::removeAllFiles(FilesToRemove);
}
+signed sys::InvokeExceptionHandler(int &RetCode, void *) {
+ SignalHandler(RetCode);
+ // llvm/lib/Support/Unix/Program.inc:Wait() returns -2 if a crash occurs,
+ // not the actual error code. If we want to diagnose a crash in the same
+ // way as invoking/forking a new process (in
+ // clang/tools/driver/driver.cpp), we need to do this here.
+ if (WIFSIGNALED(RetCode))
+ RetCode = -2;
+ return 0;
+}
+
// The signal handler that runs.
static RETSIGTYPE SignalHandler(int Sig) {
// Restore the signal behavior to default, so that the program actually
@@ -361,8 +372,8 @@
{
RemoveFilesToRemove();
- if (std::find(std::begin(IntSigs), std::end(IntSigs), Sig)
- != std::end(IntSigs)) {
+ if (std::find(std::begin(IntSigs), std::end(IntSigs), Sig) !=
+ std::end(IntSigs)) {
if (auto OldInterruptFunction = InterruptFunction.exchange(nullptr))
return OldInterruptFunction();
@@ -371,9 +382,9 @@
OneShotPipeSignalFunction.exchange(nullptr))
return OldOneShotPipeFunction();
- raise(Sig); // Execute the default handler.
+ raise(Sig); // Execute the default handler.
return;
- }
+ }
}
// Otherwise if it is a fault (like SEGV) run any handler.
Index: llvm/lib/Support/CrashRecoveryContext.cpp
===================================================================
--- llvm/lib/Support/CrashRecoveryContext.cpp
+++ llvm/lib/Support/CrashRecoveryContext.cpp
@@ -10,9 +10,13 @@
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Signals.h"
#include "llvm/Support/ThreadLocal.h"
#include <mutex>
#include <setjmp.h>
+#ifdef _WIN32
+#include <excpt.h> // for GetExceptionInformation
+#endif
using namespace llvm;
namespace {
@@ -54,7 +58,7 @@
#endif
}
- void HandleCrash() {
+ void HandleCrash(int RetCode, void *ExceptionInfo) {
// Eliminate the current context entry, to avoid re-entering in case the
// cleanup code crashes.
CurrentContext->set(Next);
@@ -62,7 +66,11 @@
assert(!Failed && "Crash recovery context already failed!");
Failed = true;
- // FIXME: Stash the backtrace.
+ if (CRC->EnableExceptionHandler)
+ sys::InvokeExceptionHandler(RetCode, ExceptionInfo);
+
+ // Should come after InvokeExceptionHandler(), it could modify RetCode.
+ CRC->RetCode = RetCode;
// Jump back to the RunSafely we were called under.
longjmp(JumpBuffer, 1);
@@ -71,8 +79,9 @@
}
+static std::atomic<bool> gCrashRecoveryEnabled{ true };
static ManagedStatic<std::mutex> gCrashRecoveryContextMutex;
-static bool gCrashRecoveryEnabled = false;
+static bool gCrashRecoveryInstalled;
static ManagedStatic<sys::ThreadLocal<const CrashRecoveryContext>>
tlIsRecoveringFromCrash;
@@ -80,8 +89,32 @@
static void installExceptionOrSignalHandlers();
static void uninstallExceptionOrSignalHandlers();
+static void Install() {
+ if (!gCrashRecoveryEnabled)
+ return;
+ std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
+ if (gCrashRecoveryInstalled)
+ return;
+ installExceptionOrSignalHandlers();
+ gCrashRecoveryInstalled = true;
+}
+
+static void Uninstall() {
+ if (!gCrashRecoveryEnabled)
+ return;
+ std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
+ if (!gCrashRecoveryInstalled)
+ return;
+ uninstallExceptionOrSignalHandlers();
+ gCrashRecoveryInstalled = false;
+}
+
CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup() {}
+CrashRecoveryContext::CrashRecoveryContext() : Impl(nullptr), head(nullptr) {
+ Install();
+}
+
CrashRecoveryContext::~CrashRecoveryContext() {
// Reclaim registered resources.
CrashRecoveryContextCleanup *i = head;
@@ -115,21 +148,11 @@
return CRCI->CRC;
}
-void CrashRecoveryContext::Enable() {
- std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
- // FIXME: Shouldn't this be a refcount or something?
- if (gCrashRecoveryEnabled)
- return;
- gCrashRecoveryEnabled = true;
- installExceptionOrSignalHandlers();
-}
+void CrashRecoveryContext::Enable() { gCrashRecoveryEnabled = true; }
void CrashRecoveryContext::Disable() {
- std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
- if (!gCrashRecoveryEnabled)
- return;
+ Uninstall();
gCrashRecoveryEnabled = false;
- uninstallExceptionOrSignalHandlers();
}
void CrashRecoveryContext::registerCleanup(CrashRecoveryContextCleanup *cleanup)
@@ -171,19 +194,25 @@
static void installExceptionOrSignalHandlers() {}
static void uninstallExceptionOrSignalHandlers() {}
-bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) {
- if (!gCrashRecoveryEnabled) {
+static bool InvokeFunctionCall(function_ref<void()> Fn, bool ExceptionHandler,
+ int &RetCode) {
+ __try {
Fn();
- return true;
+ } __except (ExceptionHandler ? sys::InvokeExceptionHandler(
+ RetCode, GetExceptionInformation())
+ : 1) {
+ RetCode = GetExceptionCode();
+ return false;
}
+ return true;
+}
- bool Result = true;
- __try {
+bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) {
+ if (!gCrashRecoveryEnabled) {
Fn();
- } __except (1) { // Catch any exception.
- Result = false;
+ return true;
}
- return Result;
+ return InvokeFunctionCall(Fn, EnableExceptionHandler, RetCode);
}
#else // !_MSC_VER
@@ -237,7 +266,8 @@
// implementation if we so choose.
// Handle the crash
- const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
+ const_cast<CrashRecoveryContextImpl *>(CRCI)->HandleCrash(
+ (int)ExceptionInfo->ExceptionRecord->ExceptionCode, ExceptionInfo);
// Note that we don't actually get here because HandleCrash calls
// longjmp, which means the HandleCrash function never returns.
@@ -304,8 +334,6 @@
// 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);
@@ -320,7 +348,7 @@
sigprocmask(SIG_UNBLOCK, &SigMask, nullptr);
if (CRCI)
- const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
+ const_cast<CrashRecoveryContextImpl *>(CRCI)->HandleCrash(Signal, nullptr);
}
static void installExceptionOrSignalHandlers() {
@@ -345,7 +373,7 @@
bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) {
// If crash recovery is disabled, do nothing.
- if (gCrashRecoveryEnabled) {
+ if (IsEnabled()) {
assert(!Impl && "Crash recovery context already initialized!");
CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this);
Impl = CRCI;
@@ -364,7 +392,7 @@
void CrashRecoveryContext::HandleCrash() {
CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
assert(CRCI && "Crash recovery context never initialized!");
- CRCI->HandleCrash();
+ CRCI->HandleCrash(-1, nullptr);
}
// FIXME: Portability.
Index: llvm/include/llvm/Support/Signals.h
===================================================================
--- llvm/include/llvm/Support/Signals.h
+++ llvm/include/llvm/Support/Signals.h
@@ -106,6 +106,14 @@
/// On Unix systems, this function exits with an "IO error" exit code.
/// This is a no-op on Windows.
void DefaultOneShotPipeSignalHandler();
+
+ /// Forcibly triggers the exception processing, but does not throw the
+ /// exception afterwards. Let the handler modify the RetCode to properly
+ /// handle diagnostics in the clang tool.
+ /// The return value is platform-specific: on Windows it indicates what action
+ /// the exception handler should take next; on Linux, the return value is
+ /// ignored and is always zero.
+ signed InvokeExceptionHandler(int &RetCode, void *ExceptionInfo);
} // End sys namespace
} // End llvm namespace
Index: llvm/include/llvm/Support/CrashRecoveryContext.h
===================================================================
--- llvm/include/llvm/Support/CrashRecoveryContext.h
+++ llvm/include/llvm/Support/CrashRecoveryContext.h
@@ -48,7 +48,7 @@
CrashRecoveryContextCleanup *head;
public:
- CrashRecoveryContext() : Impl(nullptr), head(nullptr) {}
+ CrashRecoveryContext();
~CrashRecoveryContext();
/// Register cleanup handler, which is used when the recovery context is
@@ -100,6 +100,15 @@
/// Explicitly trigger a crash recovery in the current process, and
/// return failure from RunSafely(). This function does not return.
void HandleCrash();
+
+ /// In case of a crash, this is the crash identifier
+ int RetCode = 0;
+
+ /// Selects whether the global exception handler should be called. When this
+ /// is active, a crash has the same side-effect as uncatched code (callstack
+ /// print and coredump/minidump), except that here we recover the execution
+ /// flow after the call to RunSafely().
+ bool EnableExceptionHandler = false;
};
/// Abstract base class of cleanup handlers.
Index: clang/tools/libclang/CIndex.cpp
===================================================================
--- clang/tools/libclang/CIndex.cpp
+++ clang/tools/libclang/CIndex.cpp
@@ -3290,8 +3290,8 @@
int displayDiagnostics) {
// We use crash recovery to make some of our APIs more reliable, implicitly
// enable it.
- if (!getenv("LIBCLANG_DISABLE_CRASH_RECOVERY"))
- llvm::CrashRecoveryContext::Enable();
+ if (getenv("LIBCLANG_DISABLE_CRASH_RECOVERY"))
+ llvm::CrashRecoveryContext::Disable();
// Look through the managed static to trigger construction of the managed
// static which registers our fatal error handler. This ensures it is only
Index: clang/test/Modules/signal.m
===================================================================
--- clang/test/Modules/signal.m
+++ clang/test/Modules/signal.m
@@ -2,10 +2,10 @@
// RUN: rm -rf %t
// Crash building module.
-// RUN: not --crash %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I%S/Inputs %s
+// RUN: not %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I%S/Inputs %s
-// The dead symlink is still around, but the underlying lock file is gone.
-// RUN: find %t -name "crash-*.pcm.lock" | count 1
+// All the temp files should be gone.
+// RUN: find %t -name "crash-*.pcm.lock" | count 0
// RUN: find %t -name "crash-*.pcm.lock-*" | count 0
@import crash;
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