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 }
112