llvm-6502/tools/bugpoint/FindBugs.cpp

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//===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines an interface that allows bugpoint to choose different
// combinations of optimizations to run on the selected input. Bugpoint will
// run these optimizations and record the success/failure of each. This way
// we can hopefully spot bugs in the optimizations.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ToolRunner.h"
#include "llvm/Pass.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <ctime>
using namespace llvm;
/// runManyPasses - Take the specified pass list and create different
/// combinations of passes to compile the program with. Compile the program with
/// each set and mark test to see if it compiled correctly. If the passes
/// compiled correctly output nothing and rearrange the passes into a new order.
/// If the passes did not compile correctly, output the command required to
/// recreate the failure. This returns true if a compiler error is found.
///
bool BugDriver::runManyPasses(const std::vector<std::string> &AllPasses,
std::string &ErrMsg) {
setPassesToRun(AllPasses);
outs() << "Starting bug finding procedure...\n\n";
// Creating a reference output if necessary
if (initializeExecutionEnvironment()) return false;
outs() << "\n";
if (ReferenceOutputFile.empty()) {
outs() << "Generating reference output from raw program: \n";
if (!createReferenceFile(Program))
return false;
}
srand(time(nullptr));
unsigned num = 1;
while(1) {
//
// Step 1: Randomize the order of the optimizer passes.
//
std::random_shuffle(PassesToRun.begin(), PassesToRun.end());
//
// Step 2: Run optimizer passes on the program and check for success.
//
outs() << "Running selected passes on program to test for crash: ";
for(int i = 0, e = PassesToRun.size(); i != e; i++) {
outs() << "-" << PassesToRun[i] << " ";
}
std::string Filename;
if(runPasses(Program, PassesToRun, Filename, false)) {
outs() << "\n";
outs() << "Optimizer passes caused failure!\n\n";
debugOptimizerCrash();
return true;
} else {
outs() << "Combination " << num << " optimized successfully!\n";
}
//
// Step 3: Compile the optimized code.
//
outs() << "Running the code generator to test for a crash: ";
std::string Error;
compileProgram(Program, &Error);
if (!Error.empty()) {
outs() << "\n*** compileProgram threw an exception: ";
outs() << Error;
return debugCodeGeneratorCrash(ErrMsg);
}
outs() << '\n';
//
// Step 4: Run the program and compare its output to the reference
// output (created above).
//
outs() << "*** Checking if passes caused miscompliation:\n";
bool Diff = diffProgram(Program, Filename, "", false, &Error);
if (Error.empty() && Diff) {
outs() << "\n*** diffProgram returned true!\n";
debugMiscompilation(&Error);
if (Error.empty())
return true;
}
if (!Error.empty()) {
errs() << Error;
debugCodeGeneratorCrash(ErrMsg);
return true;
}
outs() << "\n*** diff'd output matches!\n";
sys::fs::remove(Filename);
outs() << "\n\n";
num++;
} //end while
// Unreachable.
}