99 lines · cpp
1//===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file defines an interface that allows bugpoint to choose different10// combinations of optimizations to run on the selected input. Bugpoint will11// run these optimizations and record the success/failure of each. This way12// we can hopefully spot bugs in the optimizations.13//14//===----------------------------------------------------------------------===//15 16#include "BugDriver.h"17#include "llvm/Support/FileSystem.h"18#include "llvm/Support/raw_ostream.h"19#include <random>20using namespace llvm;21 22Error23BugDriver::runManyPasses(const std::vector<std::string> &AllPasses) {24 setPassesToRun(AllPasses);25 outs() << "Starting bug finding procedure...\n\n";26 27 // Creating a reference output if necessary28 if (Error E = initializeExecutionEnvironment())29 return E;30 31 outs() << "\n";32 if (ReferenceOutputFile.empty()) {33 outs() << "Generating reference output from raw program: \n";34 if (Error E = createReferenceFile(*Program))35 return E;36 }37 38 std::mt19937 randomness(std::random_device{}());39 unsigned num = 1;40 while (true) {41 //42 // Step 1: Randomize the order of the optimizer passes.43 //44 llvm::shuffle(PassesToRun.begin(), PassesToRun.end(), randomness);45 46 //47 // Step 2: Run optimizer passes on the program and check for success.48 //49 outs() << "Running selected passes on program to test for crash: ";50 for (const std::string &Pass : PassesToRun)51 outs() << "-" << Pass << " ";52 53 std::string Filename;54 if (runPasses(*Program, PassesToRun, Filename, false)) {55 outs() << "\n";56 outs() << "Optimizer passes caused failure!\n\n";57 return debugOptimizerCrash();58 } else {59 outs() << "Combination " << num << " optimized successfully!\n";60 }61 62 //63 // Step 3: Compile the optimized code.64 //65 outs() << "Running the code generator to test for a crash: ";66 if (Error E = compileProgram(*Program)) {67 outs() << "\n*** compileProgram threw an exception: ";68 outs() << toString(std::move(E));69 return debugCodeGeneratorCrash();70 }71 outs() << '\n';72 73 //74 // Step 4: Run the program and compare its output to the reference75 // output (created above).76 //77 outs() << "*** Checking if passes caused miscompliation:\n";78 Expected<bool> Diff = diffProgram(*Program, Filename, "", false);79 if (Error E = Diff.takeError()) {80 errs() << toString(std::move(E));81 return debugCodeGeneratorCrash();82 }83 if (*Diff) {84 outs() << "\n*** diffProgram returned true!\n";85 Error E = debugMiscompilation();86 if (!E)87 return Error::success();88 }89 outs() << "\n*** diff'd output matches!\n";90 91 sys::fs::remove(Filename);92 93 outs() << "\n\n";94 num++;95 } // end while96 97 // Unreachable.98}99