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 "ReducerWorkItem.h"
19 #include "TestRunner.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/CodeGen/CommandFlags.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/Verifier.h"
26 #include "llvm/IRReader/IRReader.h"
27 #include "llvm/MC/TargetRegistry.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Host.h"
30 #include "llvm/Support/InitLLVM.h"
31 #include "llvm/Support/SourceMgr.h"
32 #include "llvm/Support/TargetSelect.h"
33 #include "llvm/Support/WithColor.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include <system_error>
36 #include <vector>
37 
38 using namespace llvm;
39 
40 cl::OptionCategory LLVMReduceOptions("llvm-reduce options");
41 
42 static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
43                           cl::cat(LLVMReduceOptions));
44 static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden,
45                              cl::cat(LLVMReduceOptions));
46 
47 static cl::opt<bool>
48     PrintDeltaPasses("print-delta-passes",
49                      cl::desc("Print list of delta passes, passable to "
50                               "--delta-passes as a comma separated list"),
51                      cl::cat(LLVMReduceOptions));
52 
53 static cl::opt<std::string> InputFilename(cl::Positional, cl::Required,
54                                           cl::desc("<input llvm ll/bc file>"),
55                                           cl::cat(LLVMReduceOptions));
56 
57 static cl::opt<std::string>
58     TestFilename("test", cl::Required,
59                  cl::desc("Name of the interesting-ness test to be run"),
60                  cl::cat(LLVMReduceOptions));
61 
62 static cl::list<std::string>
63     TestArguments("test-arg",
64                   cl::desc("Arguments passed onto the interesting-ness test"),
65                   cl::cat(LLVMReduceOptions));
66 
67 static cl::opt<std::string> OutputFilename(
68     "output", cl::desc("Specify the output file. default: reduced.ll|mir"));
69 static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
70                                  cl::aliasopt(OutputFilename),
71                                  cl::cat(LLVMReduceOptions));
72 
73 static cl::opt<bool>
74     ReplaceInput("in-place",
75                  cl::desc("WARNING: This option will replace your input file "
76                           "with the reduced version!"),
77                  cl::cat(LLVMReduceOptions));
78 
79 enum class InputLanguages { None, IR, MIR };
80 
81 static cl::opt<InputLanguages>
82     InputLanguage("x", cl::ValueOptional,
83                   cl::desc("Input language ('ir' or 'mir')"),
84                   cl::init(InputLanguages::None),
85                   cl::values(clEnumValN(InputLanguages::IR, "ir", ""),
86                              clEnumValN(InputLanguages::MIR, "mir", "")),
87                   cl::cat(LLVMReduceOptions));
88 
89 static cl::opt<int>
90     MaxPassIterations("max-pass-iterations",
91                       cl::desc("Maximum number of times to run the full set "
92                                "of delta passes (default=5)"),
93                       cl::init(5), cl::cat(LLVMReduceOptions));
94 
95 static codegen::RegisterCodeGenFlags CGF;
96 
97 static void initializeTargetInfo() {
98   InitializeAllTargets();
99   InitializeAllTargetMCs();
100   InitializeAllAsmPrinters();
101   InitializeAllAsmParsers();
102 }
103 
104 void writeOutput(ReducerWorkItem &M, StringRef Message) {
105   if (ReplaceInput) // In-place
106     OutputFilename = InputFilename.c_str();
107   else if (OutputFilename.empty() || OutputFilename == "-")
108     OutputFilename = M.isMIR() ? "reduced.mir" : "reduced.ll";
109   std::error_code EC;
110   raw_fd_ostream Out(OutputFilename, EC);
111   if (EC) {
112     errs() << "Error opening output file: " << EC.message() << "!\n";
113     exit(1);
114   }
115   M.print(Out, /*AnnotationWriter=*/nullptr);
116   errs() << Message << OutputFilename << "\n";
117 }
118 
119 int main(int Argc, char **Argv) {
120   InitLLVM X(Argc, Argv);
121 
122   cl::HideUnrelatedOptions({&LLVMReduceOptions, &getColorCategory()});
123   cl::ParseCommandLineOptions(Argc, Argv, "LLVM automatic testcase reducer.\n");
124 
125   bool ReduceModeMIR = false;
126   if (InputLanguage != InputLanguages::None) {
127     if (InputLanguage == InputLanguages::MIR)
128       ReduceModeMIR = true;
129   } else if (StringRef(InputFilename).endswith(".mir")) {
130     ReduceModeMIR = true;
131   }
132 
133   if (PrintDeltaPasses) {
134     printDeltaPasses(errs());
135     return 0;
136   }
137 
138   if (ReduceModeMIR)
139     initializeTargetInfo();
140 
141   LLVMContext Context;
142   std::unique_ptr<TargetMachine> TM;
143 
144   std::unique_ptr<ReducerWorkItem> OriginalProgram =
145       parseReducerWorkItem(Argv[0], InputFilename, Context, TM, ReduceModeMIR);
146   if (!OriginalProgram) {
147     return 1;
148   }
149 
150   // Initialize test environment
151   TestRunner Tester(TestFilename, TestArguments, std::move(OriginalProgram),
152                     std::move(TM));
153 
154   // Try to reduce code
155   runDeltaPasses(Tester, MaxPassIterations);
156 
157   // Print reduced file to STDOUT
158   if (OutputFilename == "-")
159     Tester.getProgram().print(outs(), nullptr);
160   else
161     writeOutput(Tester.getProgram(), "\nDone reducing! Reduced testcase: ");
162 
163   return 0;
164 }
165