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//===--- llvm-isel-fuzzer.cpp - Fuzzer for instruction selection ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Tool to fuzz instruction selection using libFuzzer.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#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/IR/Constants.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetMachine.h"
#define DEBUG_TYPE "isel-fuzzer"
using namespace llvm;
static codegen::RegisterCodeGenFlags CGF;
static cl::opt<char>
OptLevel("O",
cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
"(default = '-O2')"),
cl::Prefix, cl::init('2'));
static cl::opt<std::string>
TargetTriple("mtriple", cl::desc("Override target triple for module"));
static std::unique_ptr<TargetMachine> TM;
static std::unique_ptr<IRMutator> Mutator;
std::unique_ptr<IRMutator> createISelMutator() {
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.emplace_back(
new InjectorIRStrategy(InjectorIRStrategy::getDefaultOps()));
Strategies.emplace_back(new InstDeleterIRStrategy());
return std::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) {
LLVMContext Context;
std::unique_ptr<Module> M;
if (Size <= 1)
// We get bogus data given an empty corpus - just create a new module.
M.reset(new Module("M", Context));
else
M = parseModule(Data, Size, Context);
Mutator->mutateModule(*M, Seed, MaxSize); // use max bitcode size as a guide
return writeModule(*M, Data, MaxSize);
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
if (Size <= 1)
// We get bogus data given an empty corpus - ignore it.
return 0;
LLVMContext Context;
auto M = parseAndVerify(Data, Size, Context);
if (!M) {
errs() << "error: input module is broken!\n";
return 0;
}
// Set up the module to build for our target.
M->setTargetTriple(TM->getTargetTriple().normalize());
M->setDataLayout(TM->createDataLayout());
// Build up a PM to do instruction selection.
legacy::PassManager PM;
TargetLibraryInfoImpl TLII(TM->getTargetTriple());
PM.add(new TargetLibraryInfoWrapperPass(TLII));
raw_null_ostream OS;
TM->addPassesToEmitFile(PM, OS, nullptr, CodeGenFileType::Null);
PM.run(*M);
return 0;
}
static void handleLLVMFatalError(void *, const char *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;
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
InitializeAllAsmParsers();
handleExecNameEncodedBEOpts(*argv[0]);
parseFuzzerCLOpts(*argc, *argv);
if (TargetTriple.empty()) {
errs() << *argv[0] << ": -mtriple must be specified\n";
exit(1);
}
// Set up the pipeline like llc does.
CodeGenOptLevel OLvl;
if (auto Level = CodeGenOpt::parseLevel(OptLevel)) {
OLvl = *Level;
} else {
errs() << argv[0] << ": invalid optimization level.\n";
return 1;
}
ExitOnError ExitOnErr(std::string(*argv[0]) + ": error:");
TM = ExitOnErr(codegen::createTargetMachineForTriple(
Triple::normalize(TargetTriple), OLvl));
assert(TM && "Could not allocate target machine!");
// Make sure we print the summary and the current unit when LLVM errors out.
install_fatal_error_handler(handleLLVMFatalError, nullptr);
// Finally, create our mutator.
Mutator = createISelMutator();
return 0;
}
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