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/MemoryBufferRef.h"
25 #include "llvm/Support/Process.h"
26 #include "llvm/Support/WithColor.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include <system_error>
29 #include <vector>
30
31 #ifdef _WIN32
32 #include <windows.h>
33 #endif
34
35 using namespace llvm;
36
37 cl::OptionCategory LLVMReduceOptions("llvm-reduce options");
38
39 static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
40 cl::cat(LLVMReduceOptions));
41 static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden,
42 cl::cat(LLVMReduceOptions));
43
44 static cl::opt<bool> PreserveDebugEnvironment(
45 "preserve-debug-environment",
46 cl::desc("Don't disable features used for crash "
47 "debugging (crash reports, llvm-symbolizer and core dumps)"),
48 cl::cat(LLVMReduceOptions));
49
50 static cl::opt<bool>
51 PrintDeltaPasses("print-delta-passes",
52 cl::desc("Print list of delta passes, passable to "
53 "--delta-passes as a comma separated list"),
54 cl::cat(LLVMReduceOptions));
55
56 static cl::opt<std::string> InputFilename(cl::Positional,
57 cl::desc("<input llvm ll/bc file>"),
58 cl::cat(LLVMReduceOptions));
59
60 static cl::opt<std::string>
61 TestFilename("test",
62 cl::desc("Name of the interesting-ness test to be run"),
63 cl::cat(LLVMReduceOptions));
64
65 static cl::list<std::string>
66 TestArguments("test-arg",
67 cl::desc("Arguments passed onto the interesting-ness test"),
68 cl::cat(LLVMReduceOptions));
69
70 static cl::opt<std::string> OutputFilename(
71 "output",
72 cl::desc("Specify the output file. default: reduced.ll|.bc|.mir"));
73 static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
74 cl::aliasopt(OutputFilename),
75 cl::cat(LLVMReduceOptions));
76
77 static cl::opt<bool>
78 ReplaceInput("in-place",
79 cl::desc("WARNING: This option will replace your input file "
80 "with the reduced version!"),
81 cl::cat(LLVMReduceOptions));
82
83 enum class InputLanguages { None, IR, MIR };
84
85 static cl::opt<InputLanguages>
86 InputLanguage("x", cl::ValueOptional,
87 cl::desc("Input language ('ir' or 'mir')"),
88 cl::init(InputLanguages::None),
89 cl::values(clEnumValN(InputLanguages::IR, "ir", ""),
90 clEnumValN(InputLanguages::MIR, "mir", "")),
91 cl::cat(LLVMReduceOptions));
92
93 static cl::opt<bool> ForceOutputBitcode(
94 "output-bitcode",
95 cl::desc("Emit final result as bitcode instead of text IR"), cl::Hidden,
96 cl::cat(LLVMReduceOptions));
97
98 static cl::opt<int>
99 MaxPassIterations("max-pass-iterations",
100 cl::desc("Maximum number of times to run the full set "
101 "of delta passes (default=5)"),
102 cl::init(5), cl::cat(LLVMReduceOptions));
103
104 static codegen::RegisterCodeGenFlags CGF;
105
106 /// Turn off crash debugging features
107 ///
108 /// Crash is expected, so disable crash reports and symbolization to reduce
109 /// output clutter and avoid potentially slow symbolization.
disableEnvironmentDebugFeatures()110 static void disableEnvironmentDebugFeatures() {
111 sys::Process::PreventCoreFiles();
112
113 // TODO: Copied from not. Should have a wrapper around setenv.
114 #ifdef _WIN32
115 SetEnvironmentVariableA("LLVM_DISABLE_CRASH_REPORT", "1");
116 SetEnvironmentVariableA("LLVM_DISABLE_SYMBOLIZATION", "1");
117 #else
118 setenv("LLVM_DISABLE_CRASH_REPORT", "1", /*overwrite=*/1);
119 setenv("LLVM_DISABLE_SYMBOLIZATION", "1", /*overwrite=*/1);
120 #endif
121 }
122
determineOutputType(bool IsMIR,bool InputIsBitcode)123 static std::pair<StringRef, bool> determineOutputType(bool IsMIR,
124 bool InputIsBitcode) {
125 bool OutputBitcode = ForceOutputBitcode || InputIsBitcode;
126
127 if (ReplaceInput) { // In-place
128 OutputFilename = InputFilename.c_str();
129 } else if (OutputFilename.empty()) {
130 // Default to producing bitcode if the input was bitcode, if not explicitly
131 // requested.
132
133 OutputFilename =
134 IsMIR ? "reduced.mir" : (OutputBitcode ? "reduced.bc" : "reduced.ll");
135 }
136
137 return {OutputFilename, OutputBitcode};
138 }
139
main(int Argc,char ** Argv)140 int main(int Argc, char **Argv) {
141 InitLLVM X(Argc, Argv);
142 const StringRef ToolName(Argv[0]);
143
144 cl::HideUnrelatedOptions({&LLVMReduceOptions, &getColorCategory()});
145 cl::ParseCommandLineOptions(Argc, Argv, "LLVM automatic testcase reducer.\n");
146
147 if (Argc == 1) {
148 cl::PrintHelpMessage();
149 return 0;
150 }
151
152 if (PrintDeltaPasses) {
153 printDeltaPasses(outs());
154 return 0;
155 }
156
157 bool ReduceModeMIR = false;
158 if (InputLanguage != InputLanguages::None) {
159 if (InputLanguage == InputLanguages::MIR)
160 ReduceModeMIR = true;
161 } else if (StringRef(InputFilename).endswith(".mir")) {
162 ReduceModeMIR = true;
163 }
164
165 if (InputFilename.empty()) {
166 WithColor::error(errs(), ToolName)
167 << "reduction testcase positional argument must be specified\n";
168 return 1;
169 }
170
171 if (TestFilename.empty()) {
172 WithColor::error(errs(), ToolName) << "--test option must be specified\n";
173 return 1;
174 }
175
176 if (!PreserveDebugEnvironment)
177 disableEnvironmentDebugFeatures();
178
179 LLVMContext Context;
180 std::unique_ptr<TargetMachine> TM;
181
182 auto [OriginalProgram, InputIsBitcode] =
183 parseReducerWorkItem(ToolName, InputFilename, Context, TM, ReduceModeMIR);
184 if (!OriginalProgram) {
185 return 1;
186 }
187
188 StringRef OutputFilename;
189 bool OutputBitcode;
190 std::tie(OutputFilename, OutputBitcode) =
191 determineOutputType(ReduceModeMIR, InputIsBitcode);
192
193 // Initialize test environment
194 TestRunner Tester(TestFilename, TestArguments, std::move(OriginalProgram),
195 std::move(TM), ToolName, OutputFilename, InputIsBitcode,
196 OutputBitcode);
197
198 // This parses and writes out the testcase into a temporary file copy for the
199 // test, rather than evaluating the source IR directly. This is for the
200 // convenience of lit tests; the stripped out comments may have broken the
201 // interestingness checks.
202 if (!Tester.getProgram().isReduced(Tester)) {
203 errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
204 return 1;
205 }
206
207 // Try to reduce code
208 runDeltaPasses(Tester, MaxPassIterations);
209
210 // Print reduced file to STDOUT
211 if (OutputFilename == "-")
212 Tester.getProgram().print(outs(), nullptr);
213 else
214 Tester.writeOutput("Done reducing! Reduced testcase: ");
215
216 return 0;
217 }
218