--- /dev/null
+//===--- llvm-opt-fuzzer.cpp - Fuzzer for instruction selection ----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Tool to fuzz optimization passes using libFuzzer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
+#include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/FuzzMutate/FuzzerCLI.h"
+#include "llvm/FuzzMutate/IRMutator.h"
+#include "llvm/FuzzMutate/Operations.h"
+#include "llvm/FuzzMutate/Random.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+
+using namespace llvm;
+
+static cl::opt<std::string>
+ TargetTripleStr("mtriple", cl::desc("Override target triple for module"));
+
+// Passes to run for this fuzzer instance. Expects new pass manager syntax.
+static cl::opt<std::string> PassPipeline(
+ "passes",
+ cl::desc("A textual description of the pass pipeline for testing"));
+
+static std::unique_ptr<IRMutator> Mutator;
+static std::unique_ptr<TargetMachine> TM;
+
+// This function is mostly copied from the llvm-isel-fuzzer.
+// TODO: Move this into FuzzMutate library and reuse.
+static std::unique_ptr<Module> parseModule(const uint8_t *Data, size_t Size,
+ LLVMContext &Context) {
+
+ if (Size <= 1)
+ // We get bogus data given an empty corpus - just create a new module.
+ return llvm::make_unique<Module>("M", Context);
+
+ auto Buffer = MemoryBuffer::getMemBuffer(
+ StringRef(reinterpret_cast<const char *>(Data), Size), "Fuzzer input",
+ /*RequiresNullTerminator=*/false);
+
+ SMDiagnostic Err;
+ auto M = parseBitcodeFile(Buffer->getMemBufferRef(), Context);
+ if (Error E = M.takeError()) {
+ errs() << toString(std::move(E)) << "\n";
+ return nullptr;
+ }
+ return std::move(M.get());
+}
+
+// This function is copied from the llvm-isel-fuzzer.
+// TODO: Move this into FuzzMutate library and reuse.
+static size_t writeModule(const Module &M, uint8_t *Dest, size_t MaxSize) {
+ std::string Buf;
+ {
+ raw_string_ostream OS(Buf);
+ WriteBitcodeToFile(&M, OS);
+ }
+ if (Buf.size() > MaxSize)
+ return 0;
+ memcpy(Dest, Buf.data(), Buf.size());
+ return Buf.size();
+}
+
+std::unique_ptr<IRMutator> createOptMutator() {
+ std::vector<TypeGetter> Types{
+ Type::getInt1Ty, Type::getInt8Ty, Type::getInt16Ty, Type::getInt32Ty,
+ Type::getInt64Ty, Type::getFloatTy, Type::getDoubleTy};
+
+ std::vector<std::unique_ptr<IRMutationStrategy>> Strategies;
+ Strategies.push_back(
+ llvm::make_unique<InjectorIRStrategy>(
+ InjectorIRStrategy::getDefaultOps()));
+ Strategies.push_back(
+ llvm::make_unique<InstDeleterIRStrategy>());
+
+ return llvm::make_unique<IRMutator>(std::move(Types), std::move(Strategies));
+}
+
+extern "C" LLVM_ATTRIBUTE_USED size_t LLVMFuzzerCustomMutator(
+ uint8_t *Data, size_t Size, size_t MaxSize, unsigned int Seed) {
+
+ assert(Mutator &&
+ "IR mutator should have been created during fuzzer initialization");
+
+ LLVMContext Context;
+ auto M = parseModule(Data, Size, Context);
+ if (!M || verifyModule(*M, &errs())) {
+ errs() << "error: mutator input module is broken!\n";
+ return 0;
+ }
+
+ Mutator->mutateModule(*M, Seed, Size, MaxSize);
+
+#ifndef NDEBUG
+ if (verifyModule(*M, &errs())) {
+ errs() << "mutation result doesn't pass verification\n";
+ M->dump();
+ abort();
+ }
+#endif
+
+ return writeModule(*M, Data, MaxSize);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+ assert(TM && "Should have been created during fuzzer initialization");
+
+ if (Size <= 1)
+ // We get bogus data given an empty corpus - ignore it.
+ return 0;
+
+ // Parse module
+ //
+
+ LLVMContext Context;
+ auto M = parseModule(Data, Size, Context);
+ if (!M || verifyModule(*M, &errs())) {
+ errs() << "error: input module is broken!\n";
+ return 0;
+ }
+
+ // Set up target dependant options
+ //
+
+ M->setTargetTriple(TM->getTargetTriple().normalize());
+ M->setDataLayout(TM->createDataLayout());
+ setFunctionAttributes(TM->getTargetCPU(), TM->getTargetFeatureString(), *M);
+
+ // Create pass pipeline
+ //
+
+ PassBuilder PB(TM.get());
+
+ LoopAnalysisManager LAM;
+ FunctionAnalysisManager FAM;
+ CGSCCAnalysisManager CGAM;
+ ModulePassManager MPM;
+ ModuleAnalysisManager MAM;
+
+ FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
+ PB.registerModuleAnalyses(MAM);
+ PB.registerCGSCCAnalyses(CGAM);
+ PB.registerFunctionAnalyses(FAM);
+ PB.registerLoopAnalyses(LAM);
+ PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
+
+ bool Ok = PB.parsePassPipeline(MPM, PassPipeline, false, false);
+ assert(Ok && "Should have been checked during fuzzer initialization");
+
+ // Run passes which we need to test
+ //
+
+ MPM.run(*M, MAM);
+
+ // Check that passes resulted in a correct code
+ if (verifyModule(*M, &errs())) {
+ errs() << "Transformation resulted in an invalid module\n";
+ abort();
+ }
+
+ return 0;
+}
+
+static void handleLLVMFatalError(void *, const std::string &Message, bool) {
+ // TODO: Would it be better to call into the fuzzer internals directly?
+ dbgs() << "LLVM ERROR: " << Message << "\n"
+ << "Aborting to trigger fuzzer exit handling.\n";
+ abort();
+}
+
+extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(
+ int *argc, char ***argv) {
+ EnableDebugBuffering = true;
+
+ // Make sure we print the summary and the current unit when LLVM errors out.
+ install_fatal_error_handler(handleLLVMFatalError, nullptr);
+
+ // Initialize llvm
+ //
+
+ InitializeAllTargets();
+ InitializeAllTargetMCs();
+
+ PassRegistry &Registry = *PassRegistry::getPassRegistry();
+ initializeCore(Registry);
+ initializeCoroutines(Registry);
+ initializeScalarOpts(Registry);
+ initializeObjCARCOpts(Registry);
+ initializeVectorization(Registry);
+ initializeIPO(Registry);
+ initializeAnalysis(Registry);
+ initializeTransformUtils(Registry);
+ initializeInstCombine(Registry);
+ initializeInstrumentation(Registry);
+ initializeTarget(Registry);
+
+ // Parse input options
+ //
+
+ handleExecNameEncodedOptimizerOpts(*argv[0]);
+ parseFuzzerCLOpts(*argc, *argv);
+
+ // Create TargetMachine
+ //
+
+ if (TargetTripleStr.empty()) {
+ errs() << *argv[0] << ": -mtriple must be specified\n";
+ exit(1);
+ }
+ Triple TargetTriple = Triple(Triple::normalize(TargetTripleStr));
+
+ std::string Error;
+ const Target *TheTarget =
+ TargetRegistry::lookupTarget(MArch, TargetTriple, Error);
+ if (!TheTarget) {
+ errs() << *argv[0] << ": " << Error;
+ exit(1);
+ }
+
+ TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
+ TM.reset(TheTarget->createTargetMachine(
+ TargetTriple.getTriple(), getCPUStr(), getFeaturesStr(),
+ Options, getRelocModel(), getCodeModel(), CodeGenOpt::Default));
+ assert(TM && "Could not allocate target machine!");
+
+ // Check that pass pipeline is specified and correct
+ //
+
+ if (PassPipeline.empty()) {
+ errs() << *argv[0] << ": at least one pass should be specified\n";
+ exit(1);
+ }
+
+ PassBuilder PB(TM.get());
+ ModulePassManager MPM;
+ if (!PB.parsePassPipeline(MPM, PassPipeline, false, false)) {
+ errs() << *argv[0] << ": can't parse pass pipeline\n";
+ exit(1);
+ }
+
+ // Create mutator
+ //
+
+ Mutator = createOptMutator();
+
+ return 0;
+}