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::OptionCategory Options("llvm-reduce options");
32 
33 static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
34                           cl::cat(Options));
35 static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden,
36                              cl::cat(Options));
37 
38 static cl::opt<std::string> InputFilename(cl::Positional, cl::Required,
39                                           cl::desc("<input llvm ll/bc file>"),
40                                           cl::cat(Options));
41 
42 static cl::opt<std::string>
43     TestFilename("test", cl::Required,
44                  cl::desc("Name of the interesting-ness test to be run"),
45                  cl::cat(Options));
46 
47 static cl::list<std::string>
48     TestArguments("test-arg", cl::ZeroOrMore,
49                   cl::desc("Arguments passed onto the interesting-ness test"),
50                   cl::cat(Options));
51 
52 static cl::opt<std::string>
53     OutputFilename("output",
54                    cl::desc("Specify the output file. default: reduced.ll"));
55 static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
56                                  cl::aliasopt(OutputFilename),
57                                  cl::cat(Options));
58 
59 static cl::opt<bool>
60     ReplaceInput("in-place",
61                  cl::desc("WARNING: This option will replace your input file "
62                           "with the reduced version!"),
63                  cl::cat(Options));
64 
65 // Parses IR into a Module and verifies it
66 static std::unique_ptr<Module> parseInputFile(StringRef Filename,
67                                               LLVMContext &Ctxt) {
68   SMDiagnostic Err;
69   std::unique_ptr<Module> Result = parseIRFile(Filename, Err, Ctxt);
70   if (!Result) {
71     Err.print("llvm-reduce", errs());
72     return Result;
73   }
74 
75   if (verifyModule(*Result, &errs())) {
76     errs() << "Error: " << Filename << " - input module is broken!\n";
77     return std::unique_ptr<Module>();
78   }
79 
80   return Result;
81 }
82 
83 void writeOutput(Module *M, StringRef Message) {
84   if (ReplaceInput) // In-place
85     OutputFilename = InputFilename.c_str();
86   else if (OutputFilename.empty() || OutputFilename == "-")
87     OutputFilename = "reduced.ll";
88 
89   std::error_code EC;
90   raw_fd_ostream Out(OutputFilename, EC);
91   if (EC) {
92     errs() << "Error opening output file: " << EC.message() << "!\n";
93     exit(1);
94   }
95   M->print(Out, /*AnnotationWriter=*/nullptr);
96   errs() << Message << OutputFilename << "\n";
97 }
98 
99 int main(int Argc, char **Argv) {
100   InitLLVM X(Argc, Argv);
101 
102   cl::ParseCommandLineOptions(Argc, Argv, "LLVM automatic testcase reducer.\n");
103 
104   LLVMContext Context;
105   std::unique_ptr<Module> OriginalProgram =
106       parseInputFile(InputFilename, Context);
107 
108   // Initialize test environment
109   TestRunner Tester(TestFilename, TestArguments);
110   Tester.setProgram(std::move(OriginalProgram));
111 
112   // Try to reduce code
113   runDeltaPasses(Tester);
114 
115   if (!Tester.getProgram()) {
116     errs() << "\nCouldnt reduce input :/\n";
117   } else {
118     // Print reduced file to STDOUT
119     if (OutputFilename == "-")
120       Tester.getProgram()->print(outs(), nullptr);
121     else
122       writeOutput(Tester.getProgram(), "\nDone reducing! Reduced testcase: ");
123   }
124 
125   return 0;
126 }
127