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llvm-mirror/tools/bugpoint/FindBugs.cpp
Alex Richardson b4fdf05aa0 Avoid shuffle self-assignment in EXPENSIVE_CHECKS builds
Some versions of libstdc++ perform self-assignment in std::shuffle. This
breaks the EXPENSIVE_CHECKS builds of TableGen due to an incorrect assertion
in libstdc++.

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85828.

Fixes https://llvm.org/PR37652

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D98167
2021-03-10 11:17:34 +00:00

100 lines
3.1 KiB
C++

//===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// 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 "llvm/Support/FileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include <random>
using namespace llvm;
Error
BugDriver::runManyPasses(const std::vector<std::string> &AllPasses) {
setPassesToRun(AllPasses);
outs() << "Starting bug finding procedure...\n\n";
// Creating a reference output if necessary
if (Error E = initializeExecutionEnvironment())
return E;
outs() << "\n";
if (ReferenceOutputFile.empty()) {
outs() << "Generating reference output from raw program: \n";
if (Error E = createReferenceFile(*Program))
return E;
}
std::mt19937 randomness(std::random_device{}());
unsigned num = 1;
while (1) {
//
// Step 1: Randomize the order of the optimizer passes.
//
llvm::shuffle(PassesToRun.begin(), PassesToRun.end(), randomness);
//
// 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";
return debugOptimizerCrash();
} else {
outs() << "Combination " << num << " optimized successfully!\n";
}
//
// Step 3: Compile the optimized code.
//
outs() << "Running the code generator to test for a crash: ";
if (Error E = compileProgram(*Program)) {
outs() << "\n*** compileProgram threw an exception: ";
outs() << toString(std::move(E));
return debugCodeGeneratorCrash();
}
outs() << '\n';
//
// Step 4: Run the program and compare its output to the reference
// output (created above).
//
outs() << "*** Checking if passes caused miscompliation:\n";
Expected<bool> Diff = diffProgram(*Program, Filename, "", false);
if (Error E = Diff.takeError()) {
errs() << toString(std::move(E));
return debugCodeGeneratorCrash();
}
if (*Diff) {
outs() << "\n*** diffProgram returned true!\n";
Error E = debugMiscompilation();
if (!E)
return Error::success();
}
outs() << "\n*** diff'd output matches!\n";
sys::fs::remove(Filename);
outs() << "\n\n";
num++;
} // end while
// Unreachable.
}