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/Bitcode/BitcodeReader.h"
21#include "llvm/CodeGen/CommandFlags.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/InitLLVM.h"
24#include "llvm/Support/Process.h"
25#include "llvm/Support/WithColor.h"
26#include "llvm/Support/raw_ostream.h"
27
28#ifdef _WIN32
29#include <windows.h>
30#endif
31
32using namespace llvm;
33
34cl::OptionCategory LLVMReduceOptions("llvm-reduce options");
35
36static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
37 cl::cat(LLVMReduceOptions));
38static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden,
39 cl::cat(LLVMReduceOptions));
40
41static cl::opt<bool> PreserveDebugEnvironment(
42 "preserve-debug-environment",
43 cl::desc("Don't disable features used for crash "
44 "debugging (crash reports, llvm-symbolizer and core dumps)"),
45 cl::cat(LLVMReduceOptions));
46
47static 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
53static cl::opt<std::string> InputFilename(cl::Positional,
54 cl::desc("<input llvm ll/bc file>"),
55 cl::cat(LLVMReduceOptions));
56
57static cl::opt<std::string>
58 TestFilename("test",
59 cl::desc("Name of the interesting-ness test to be run"),
60 cl::cat(LLVMReduceOptions));
61
62static cl::list<std::string>
63 TestArguments("test-arg",
64 cl::desc("Arguments passed onto the interesting-ness test"),
65 cl::cat(LLVMReduceOptions));
66
67static cl::opt<std::string> OutputFilename(
68 "output",
69 cl::desc("Specify the output file. default: reduced.ll|.bc|.mir"));
70static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
71 cl::aliasopt(OutputFilename),
72 cl::cat(LLVMReduceOptions));
73
74static cl::opt<bool>
75 ReplaceInput("in-place",
76 cl::desc("WARNING: This option will replace your input file "
77 "with the reduced version!"),
78 cl::cat(LLVMReduceOptions));
79
80enum class InputLanguages { None, IR, MIR };
81
82static cl::opt<InputLanguages>
83 InputLanguage("x", cl::ValueOptional,
84 cl::desc("Input language ('ir' or 'mir')"),
85 cl::init(Val: InputLanguages::None),
86 cl::values(clEnumValN(InputLanguages::IR, "ir", ""),
87 clEnumValN(InputLanguages::MIR, "mir", "")),
88 cl::cat(LLVMReduceOptions));
89
90static cl::opt<bool> ForceOutputBitcode(
91 "output-bitcode",
92 cl::desc("Emit final result as bitcode instead of text IR"), cl::Hidden,
93 cl::cat(LLVMReduceOptions));
94
95static cl::opt<int>
96 MaxPassIterations("max-pass-iterations",
97 cl::desc("Maximum number of times to run the full set "
98 "of delta passes (default=5)"),
99 cl::init(Val: 5), cl::cat(LLVMReduceOptions));
100
101static codegen::RegisterCodeGenFlags CGF;
102
103/// Turn off crash debugging features
104///
105/// Crash is expected, so disable crash reports and symbolization to reduce
106/// output clutter and avoid potentially slow symbolization.
107static void disableEnvironmentDebugFeatures() {
108 sys::Process::PreventCoreFiles();
109
110 // TODO: Copied from not. Should have a wrapper around setenv.
111#ifdef _WIN32
112 SetEnvironmentVariableA("LLVM_DISABLE_CRASH_REPORT", "1");
113 SetEnvironmentVariableA("LLVM_DISABLE_SYMBOLIZATION", "1");
114#else
115 setenv(name: "LLVM_DISABLE_CRASH_REPORT", value: "1", /*overwrite=*/replace: 1);
116 setenv(name: "LLVM_DISABLE_SYMBOLIZATION", value: "1", /*overwrite=*/replace: 1);
117#endif
118}
119
120static std::pair<StringRef, bool> determineOutputType(bool IsMIR,
121 bool InputIsBitcode) {
122 bool OutputBitcode = ForceOutputBitcode || InputIsBitcode;
123
124 if (ReplaceInput) { // In-place
125 OutputFilename = InputFilename.c_str();
126 } else if (OutputFilename.empty()) {
127 // Default to producing bitcode if the input was bitcode, if not explicitly
128 // requested.
129
130 OutputFilename =
131 IsMIR ? "reduced.mir" : (OutputBitcode ? "reduced.bc" : "reduced.ll");
132 }
133
134 return {OutputFilename, OutputBitcode};
135}
136
137int main(int Argc, char **Argv) {
138 InitLLVM X(Argc, Argv);
139 const StringRef ToolName(Argv[0]);
140
141 cl::HideUnrelatedOptions(Categories: {&LLVMReduceOptions, &getColorCategory()});
142 cl::ParseCommandLineOptions(
143 argc: Argc, argv: Argv,
144 Overview: "LLVM automatic testcase reducer.\n"
145 "See https://llvm.org/docs/CommandGuide/llvm-reduce.html for more "
146 "information.\n");
147
148 if (Argc == 1) {
149 cl::PrintHelpMessage();
150 return 0;
151 }
152
153 if (PrintDeltaPasses) {
154 printDeltaPasses(OS&: outs());
155 return 0;
156 }
157
158 bool ReduceModeMIR = false;
159 if (InputLanguage != InputLanguages::None) {
160 if (InputLanguage == InputLanguages::MIR)
161 ReduceModeMIR = true;
162 } else if (StringRef(InputFilename).ends_with(Suffix: ".mir")) {
163 ReduceModeMIR = true;
164 }
165
166 if (InputFilename.empty()) {
167 WithColor::error(OS&: errs(), Prefix: ToolName)
168 << "reduction testcase positional argument must be specified\n";
169 return 1;
170 }
171
172 if (TestFilename.empty()) {
173 WithColor::error(OS&: errs(), Prefix: ToolName) << "--test option must be specified\n";
174 return 1;
175 }
176
177 if (!PreserveDebugEnvironment)
178 disableEnvironmentDebugFeatures();
179
180 LLVMContext Context;
181 std::unique_ptr<TargetMachine> TM;
182
183 auto [OriginalProgram, InputIsBitcode] =
184 parseReducerWorkItem(ToolName, Filename: InputFilename, Ctxt&: Context, TM, IsMIR: ReduceModeMIR);
185 if (!OriginalProgram) {
186 return 1;
187 }
188
189 StringRef OutputFilename;
190 bool OutputBitcode;
191 std::tie(args&: OutputFilename, args&: OutputBitcode) =
192 determineOutputType(IsMIR: ReduceModeMIR, InputIsBitcode);
193
194 // Initialize test environment
195 TestRunner Tester(TestFilename, TestArguments, std::move(OriginalProgram),
196 std::move(TM), ToolName, OutputFilename, InputIsBitcode,
197 OutputBitcode);
198
199 // This parses and writes out the testcase into a temporary file copy for the
200 // test, rather than evaluating the source IR directly. This is for the
201 // convenience of lit tests; the stripped out comments may have broken the
202 // interestingness checks.
203 if (!Tester.getProgram().isReduced(Test: Tester)) {
204 errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
205 return 2;
206 }
207
208 // Try to reduce code
209 runDeltaPasses(Tester, MaxPassIterations);
210
211 // Print reduced file to STDOUT
212 if (OutputFilename == "-")
213 Tester.getProgram().print(ROS&: outs(), p: nullptr);
214 else
215 Tester.writeOutput(Message: "Done reducing! Reduced testcase: ");
216
217 return 0;
218}
219