blob: ace5c958ee526f2e99118bc47b882a2560fa7451 [file] [log] [blame]
//===- llvm-reduce.cpp - The LLVM Delta Reduction utility -----------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This program tries to reduce an IR test case for a given interesting-ness
// test. It runs multiple delta debugging passes in order to minimize the input
// file. It's worth noting that this is a part of the bugpoint redesign
// proposal, and thus a *temporary* tool that will eventually be integrated
// into the bugpoint tool itself.
#include "DeltaManager.h"
#include "ReducerWorkItem.h"
#include "TestRunner.h"
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/CodeGen/CommandFlags.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/MemoryBufferRef.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <system_error>
#include <vector>
#ifdef _WIN32
#include <windows.h>
using namespace llvm;
cl::OptionCategory LLVMReduceOptions("llvm-reduce options");
static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden,
static cl::opt<bool> PreserveDebugEnvironment(
cl::desc("Don't disable features used for crash "
"debugging (crash reports, llvm-symbolizer and core dumps)"),
static cl::opt<bool>
cl::desc("Print list of delta passes, passable to "
"--delta-passes as a comma separated list"),
static cl::opt<std::string> InputFilename(cl::Positional,
cl::desc("<input llvm ll/bc file>"),
static cl::opt<std::string>
cl::desc("Name of the interesting-ness test to be run"),
static cl::list<std::string>
cl::desc("Arguments passed onto the interesting-ness test"),
static cl::opt<std::string> OutputFilename(
cl::desc("Specify the output file. default: reduced.ll|.bc|.mir"));
static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
static cl::opt<bool>
cl::desc("WARNING: This option will replace your input file "
"with the reduced version!"),
enum class InputLanguages { None, IR, MIR };
static cl::opt<InputLanguages>
InputLanguage("x", cl::ValueOptional,
cl::desc("Input language ('ir' or 'mir')"),
cl::values(clEnumValN(InputLanguages::IR, "ir", ""),
clEnumValN(InputLanguages::MIR, "mir", "")),
static cl::opt<bool> ForceOutputBitcode(
cl::desc("Emit final result as bitcode instead of text IR"), cl::Hidden,
static cl::opt<int>
cl::desc("Maximum number of times to run the full set "
"of delta passes (default=5)"),
cl::init(5), cl::cat(LLVMReduceOptions));
static codegen::RegisterCodeGenFlags CGF;
/// Turn off crash debugging features
/// Crash is expected, so disable crash reports and symbolization to reduce
/// output clutter and avoid potentially slow symbolization.
static void disableEnvironmentDebugFeatures() {
// TODO: Copied from not. Should have a wrapper around setenv.
#ifdef _WIN32
SetEnvironmentVariableA("LLVM_DISABLE_CRASH_REPORT", "1");
SetEnvironmentVariableA("LLVM_DISABLE_SYMBOLIZATION", "1");
setenv("LLVM_DISABLE_CRASH_REPORT", "1", /*overwrite=*/1);
setenv("LLVM_DISABLE_SYMBOLIZATION", "1", /*overwrite=*/1);
static std::pair<StringRef, bool> determineOutputType(bool IsMIR,
bool InputIsBitcode) {
bool OutputBitcode = ForceOutputBitcode || InputIsBitcode;
if (ReplaceInput) { // In-place
OutputFilename = InputFilename.c_str();
} else if (OutputFilename.empty()) {
// Default to producing bitcode if the input was bitcode, if not explicitly
// requested.
OutputFilename =
IsMIR ? "reduced.mir" : (OutputBitcode ? "reduced.bc" : "reduced.ll");
return {OutputFilename, OutputBitcode};
int main(int Argc, char **Argv) {
InitLLVM X(Argc, Argv);
const StringRef ToolName(Argv[0]);
cl::HideUnrelatedOptions({&LLVMReduceOptions, &getColorCategory()});
cl::ParseCommandLineOptions(Argc, Argv, "LLVM automatic testcase reducer.\n");
if (Argc == 1) {
return 0;
if (PrintDeltaPasses) {
return 0;
bool ReduceModeMIR = false;
if (InputLanguage != InputLanguages::None) {
if (InputLanguage == InputLanguages::MIR)
ReduceModeMIR = true;
} else if (StringRef(InputFilename).endswith(".mir")) {
ReduceModeMIR = true;
if (InputFilename.empty()) {
WithColor::error(errs(), ToolName)
<< "reduction testcase positional argument must be specified\n";
return 1;
if (TestFilename.empty()) {
WithColor::error(errs(), ToolName) << "--test option must be specified\n";
return 1;
if (!PreserveDebugEnvironment)
LLVMContext Context;
std::unique_ptr<TargetMachine> TM;
auto [OriginalProgram, InputIsBitcode] =
parseReducerWorkItem(ToolName, InputFilename, Context, TM, ReduceModeMIR);
if (!OriginalProgram) {
return 1;
StringRef OutputFilename;
bool OutputBitcode;
std::tie(OutputFilename, OutputBitcode) =
determineOutputType(ReduceModeMIR, InputIsBitcode);
// Initialize test environment
TestRunner Tester(TestFilename, TestArguments, std::move(OriginalProgram),
std::move(TM), ToolName, OutputFilename, InputIsBitcode,
// This parses and writes out the testcase into a temporary file copy for the
// test, rather than evaluating the source IR directly. This is for the
// convenience of lit tests; the stripped out comments may have broken the
// interestingness checks.
if (!Tester.getProgram().isReduced(Tester)) {
errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
return 1;
// Try to reduce code
runDeltaPasses(Tester, MaxPassIterations);
// Print reduced file to STDOUT
if (OutputFilename == "-")
Tester.getProgram().print(outs(), nullptr);
Tester.writeOutput("Done reducing! Reduced testcase: ");
return 0;