diff --git a/llvm/include/llvm/Passes/StandardInstrumentations.h b/llvm/include/llvm/Passes/StandardInstrumentations.h --- a/llvm/include/llvm/Passes/StandardInstrumentations.h +++ b/llvm/include/llvm/Passes/StandardInstrumentations.h @@ -480,6 +480,25 @@ std::unique_ptr HTML; }; +// Print IR on crash. +class PrintCrashIRInstrumentation { +public: + PrintCrashIRInstrumentation() + : SavedIR("*** Dump of IR Before Last Pass Unknown ***") {} + ~PrintCrashIRInstrumentation(); + void registerCallbacks(PassInstrumentationCallbacks &PIC); + void reportCrashIR(); + +protected: + std::string SavedIR; + +private: + // The crash reporter that will report on a crash. + static PrintCrashIRInstrumentation *CrashReporter; + // Crash handler registered when print-on-crash is specified. + static void SignalHandler(void *); +}; + /// This class provides an interface to register all the standard pass /// instrumentations and manages their state (if any). class StandardInstrumentations { @@ -493,6 +512,7 @@ PseudoProbeVerifier PseudoProbeVerification; InLineChangePrinter PrintChangedDiff; DotCfgChangeReporter WebsiteChangeReporter; + PrintCrashIRInstrumentation PrintCrashIR; VerifyInstrumentation Verify; bool VerifyEach; diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp --- a/llvm/lib/Passes/PassBuilder.cpp +++ b/llvm/lib/Passes/PassBuilder.cpp @@ -375,6 +375,17 @@ !printAfterPasses().empty(); } +// A pass for testing -print-on-crash. +// DO NOT USE THIS EXCEPT FOR TESTING! +class TriggerCrashPass : public PassInfoMixin { +public: + PreservedAnalyses run(Module &, ModuleAnalysisManager &) { + abort(); + return PreservedAnalyses::all(); + } + static StringRef name() { return "TriggerCrashPass"; } +}; + } // namespace PassBuilder::PassBuilder(TargetMachine *TM, PipelineTuningOptions PTO, diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def --- a/llvm/lib/Passes/PassRegistry.def +++ b/llvm/lib/Passes/PassRegistry.def @@ -114,6 +114,7 @@ MODULE_PASS("strip-nondebug", StripNonDebugSymbolsPass()) MODULE_PASS("strip-nonlinetable-debuginfo", StripNonLineTableDebugInfoPass()) MODULE_PASS("synthetic-counts-propagation", SyntheticCountsPropagation()) +MODULE_PASS("trigger-crash", TriggerCrashPass()) MODULE_PASS("verify", VerifierPass()) MODULE_PASS("view-callgraph", CallGraphViewerPass()) MODULE_PASS("wholeprogramdevirt", WholeProgramDevirtPass()) diff --git a/llvm/lib/Passes/StandardInstrumentations.cpp b/llvm/lib/Passes/StandardInstrumentations.cpp --- a/llvm/lib/Passes/StandardInstrumentations.cpp +++ b/llvm/lib/Passes/StandardInstrumentations.cpp @@ -28,12 +28,14 @@ #include "llvm/IR/PrintPasses.h" #include "llvm/IR/Verifier.h" #include "llvm/Support/CommandLine.h" +#include "llvm/Support/CrashRecoveryContext.h" #include "llvm/Support/Debug.h" #include "llvm/Support/FormatVariadic.h" #include "llvm/Support/GraphWriter.h" #include "llvm/Support/MemoryBuffer.h" #include "llvm/Support/Program.h" #include "llvm/Support/Regex.h" +#include "llvm/Support/Signals.h" #include "llvm/Support/raw_ostream.h" #include #include @@ -165,6 +167,12 @@ cl::desc("Generate dot files into specified directory for changed IRs"), cl::Hidden, cl::init("./")); +// An option to print the IR that was being processed when a pass crashes. +static cl::opt + PrintCrashIR("print-on-crash", + cl::desc("Print the last form of the IR before crash"), + cl::init(false), cl::Hidden); + namespace { // Perform a system based diff between \p Before and \p After, using @@ -2115,6 +2123,51 @@ ChangePrinter::PrintChangedDotCfgVerbose), Verify(DebugLogging), VerifyEach(VerifyEach) {} +PrintCrashIRInstrumentation *PrintCrashIRInstrumentation::CrashReporter = + nullptr; + +void PrintCrashIRInstrumentation::reportCrashIR() { dbgs() << SavedIR; } + +void PrintCrashIRInstrumentation::SignalHandler(void *) { + // Called by signal handlers so do not lock here + // Is the PrintCrashIRInstrumentation still alive? + if (!CrashReporter) + return; + + assert(PrintCrashIR && "Did not expect to get here without option set."); + CrashReporter->reportCrashIR(); +} + +PrintCrashIRInstrumentation::~PrintCrashIRInstrumentation() { + if (!CrashReporter) + return; + + assert(PrintCrashIR && "Did not expect to get here without option set."); + CrashReporter = nullptr; +} + +void PrintCrashIRInstrumentation::registerCallbacks( + PassInstrumentationCallbacks &PIC) { + if (!PrintCrashIR || CrashReporter) + return; + + sys::AddSignalHandler(SignalHandler, nullptr); + CrashReporter = this; + + PIC.registerBeforeNonSkippedPassCallback([this](StringRef PassID, Any IR) { + SavedIR.clear(); + raw_string_ostream OS(SavedIR); + OS << formatv("*** Dump of {0}IR Before Last Pass {1}", + llvm::forcePrintModuleIR() ? "Module " : "", PassID); + if (!isInteresting(IR, PassID)) { + OS << " Filtered Out ***\n"; + return; + } + OS << " Started ***\n"; + unwrapAndPrint(OS, IR); + }); +} + void StandardInstrumentations::registerCallbacks( PassInstrumentationCallbacks &PIC, FunctionAnalysisManager *FAM) { PrintIR.registerCallbacks(PIC); @@ -2130,6 +2183,7 @@ Verify.registerCallbacks(PIC); PrintChangedDiff.registerCallbacks(PIC); WebsiteChangeReporter.registerCallbacks(PIC); + PrintCrashIR.registerCallbacks(PIC); } template class ChangeReporter; diff --git a/llvm/test/Other/print-on-crash.ll b/llvm/test/Other/print-on-crash.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Other/print-on-crash.ll @@ -0,0 +1,30 @@ +; A test that the hidden option -print-on-crash properly sets a signal handler +; which gets called when a pass crashes. The trigger-crash pass asserts. + +; RUN: not --crash opt -print-on-crash -passes=trigger-crash < %s 2>&1 | FileCheck %s --check-prefix=CHECK_SIMPLE + +; A test that the signal handler set by the hidden option -print-on-crash +; is not called when no pass crashes. + +; RUN: opt -print-on-crash -passes="default" < %s 2>&1 | FileCheck %s --check-prefix=CHECK_NO_CRASH + +; RUN: not --crash opt -print-on-crash -print-module-scope -passes=trigger-crash < %s 2>&1 | FileCheck %s --check-prefix=CHECK_MODULE + +; RUN: not --crash opt -print-on-crash -print-module-scope -passes=trigger-crash -filter-passes=TriggerCrashPass < %s 2>&1 | FileCheck %s --check-prefix=CHECK_MODULE + +; RUN: not --crash opt -print-on-crash -print-module-scope -passes=trigger-crash -filter-passes=blah < %s 2>&1 | FileCheck %s --check-prefix=CHECK_FILTERED + +; CHECK_SIMPLE: *** Dump of IR Before Last Pass {{.*}} Started *** +; CHECK_SIMPLE: @main +; CHECK_SIMPLE: entry: +; CHECK_NO_CRASH-NOT: *** Dump of IR +; CHECK_MODULE: *** Dump of Module IR Before Last Pass {{.*}} Started *** +; CHECK_MODULE: ; ModuleID = {{.*}} +; CHECK_FILTERED: *** Dump of Module IR Before Last Pass {{.*}} Filtered Out *** + +define i32 @main() { +entry: + %retval = alloca i32, align 4 + store i32 0, i32* %retval, align 4 + ret i32 0 +}