tools/llvm-reduce/llvm-reduce.cpp

   1 //===- llvm-reduce.cpp - The LLVM Delta Reduction utility -----------------===//
   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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This program tries to reduce an IR test case for a given interesting-ness
  10 // test. It runs multiple delta debugging passes in order to minimize the input
  11 // file. It's worth noting that this is a part of the bugpoint redesign
  12 // proposal, and thus a *temporary* tool that will eventually be integrated
  13 // into the bugpoint tool itself.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "DeltaManager.h"
  18 #include "llvm/ADT/SmallString.h"
  19 #include "llvm/IR/LLVMContext.h"
  20 #include "llvm/IR/Verifier.h"
  21 #include "llvm/IRReader/IRReader.h"
  22 #include "llvm/Support/CommandLine.h"
  23 #include "llvm/Support/InitLLVM.h"
  24 #include "llvm/Support/SourceMgr.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include <system_error>
  27 #include <vector>
  28
  29 using namespace llvm;
  30
  31 static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden);
  32 static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden);
  33
  34 static cl::opt<std::string> InputFilename(cl::Positional, cl::Required,
  35                                           cl::desc("<input llvm ll/bc file>"));
  36
  37 static cl::opt<std::string>
  38     TestFilename("test", cl::Required,
  39                  cl::desc("Name of the interesting-ness test to be run"));
  40
  41 static cl::list<std::string>
  42     TestArguments("test-arg", cl::ZeroOrMore,
  43                   cl::desc("Arguments passed onto the interesting-ness test"));
  44
  45 static cl::opt<std::string>
  46     OutputFilename("output",
  47                    cl::desc("Specify the output file. default: reduced.ll"));
  48 static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
  49                                  cl::aliasopt(OutputFilename));
  50
  51 static cl::opt<bool>
  52     ReplaceInput("in-place",
  53                  cl::desc("WARNING: This option will replace your input file"
  54                           "with the reduced version!"));
  55
  56 // Parses IR into a Module and verifies it
  57 static std::unique_ptr<Module> parseInputFile(StringRef Filename,
  58                                               LLVMContext &Ctxt) {
  59   SMDiagnostic Err;
  60   std::unique_ptr<Module> Result = parseIRFile(Filename, Err, Ctxt);
  61   if (!Result) {
  62     Err.print("llvm-reduce", errs());
  63     return Result;
  64   }
  65
  66   if (verifyModule(*Result, &errs())) {
  67     errs() << "Error: " << Filename << " - input module is broken!\n";
  68     return std::unique_ptr<Module>();
  69   }
  70
  71   return Result;
  72 }
  73
  74 int main(int argc, char **argv) {
  75   InitLLVM X(argc, argv);
  76
  77   cl::ParseCommandLineOptions(argc, argv, "LLVM automatic testcase reducer.\n");
  78
  79   LLVMContext Context;
  80   std::unique_ptr<Module> OriginalProgram =
  81       parseInputFile(InputFilename, Context);
  82
  83   // Initialize test environment
  84   TestRunner Tester(TestFilename, TestArguments, InputFilename);
  85   Tester.setProgram(std::move(OriginalProgram));
  86
  87   // Try to reduce code
  88   runDeltaPasses(Tester);
  89   StringRef ReducedFilename = sys::path::filename(Tester.getReducedFilepath());
  90
  91   if (ReducedFilename == sys::path::filename(InputFilename)) {
  92     errs() << "\nCouldnt reduce input :/\n";
  93   } else {
  94     // Print reduced file to STDOUT
  95     if (OutputFilename == "-")
  96       Tester.getProgram()->print(outs(), nullptr);
  97     else {
  98       if (ReplaceInput) // In-place
  99         OutputFilename = InputFilename.c_str();
 100       else if (OutputFilename.empty())
 101         OutputFilename = "reduced.ll";
 102       else
 103         OutputFilename += ".ll";
 104
 105       sys::fs::copy_file(Tester.getReducedFilepath(), OutputFilename);
 106       errs() << "\nDone reducing! Reduced testcase: " << OutputFilename << "\n";
 107     }
 108   }
 109
 110   return 0;
 111 }