1//===- ExecutionDriver.cpp - Allow execution of LLVM program --------------===//
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 file contains code used to execute the program utilizing one of the
10// various ways of running LLVM bitcode.
11//
12//===----------------------------------------------------------------------===//
13
14#include "BugDriver.h"
15#include "ToolRunner.h"
16#include "llvm/Support/CommandLine.h"
17#include "llvm/Support/Debug.h"
18#include "llvm/Support/FileUtilities.h"
19#include "llvm/Support/Program.h"
20#include "llvm/Support/SystemUtils.h"
21#include "llvm/Support/raw_ostream.h"
22#include <fstream>
23
24using namespace llvm;
25
26namespace {
27// OutputType - Allow the user to specify the way code should be run, to test
28// for miscompilation.
29//
30enum OutputType {
31 AutoPick,
32 RunLLI,
33 RunJIT,
34 RunLLC,
35 RunLLCIA,
36 CompileCustom,
37 Custom
38};
39
40cl::opt<double> AbsTolerance("abs-tolerance",
41 cl::desc("Absolute error tolerated"),
42 cl::init(Val: 0.0));
43cl::opt<double> RelTolerance("rel-tolerance",
44 cl::desc("Relative error tolerated"),
45 cl::init(Val: 0.0));
46
47cl::opt<OutputType> InterpreterSel(
48 cl::desc("Specify the \"test\" i.e. suspect back-end:"),
49 cl::values(clEnumValN(AutoPick, "auto", "Use best guess"),
50 clEnumValN(RunLLI, "run-int", "Execute with the interpreter"),
51 clEnumValN(RunJIT, "run-jit", "Execute with JIT"),
52 clEnumValN(RunLLC, "run-llc", "Compile with LLC"),
53 clEnumValN(RunLLCIA, "run-llc-ia",
54 "Compile with LLC with integrated assembler"),
55 clEnumValN(CompileCustom, "compile-custom",
56 "Use -compile-command to define a command to "
57 "compile the bitcode. Useful to avoid linking."),
58 clEnumValN(Custom, "run-custom",
59 "Use -exec-command to define a command to execute "
60 "the bitcode. Useful for cross-compilation.")),
61 cl::init(Val: AutoPick));
62
63cl::opt<OutputType> SafeInterpreterSel(
64 cl::desc("Specify \"safe\" i.e. known-good backend:"),
65 cl::values(clEnumValN(AutoPick, "safe-auto", "Use best guess"),
66 clEnumValN(RunLLC, "safe-run-llc", "Compile with LLC"),
67 clEnumValN(Custom, "safe-run-custom",
68 "Use -exec-command to define a command to execute "
69 "the bitcode. Useful for cross-compilation.")),
70 cl::init(Val: AutoPick));
71
72cl::opt<std::string> SafeInterpreterPath(
73 "safe-path", cl::desc("Specify the path to the \"safe\" backend program"),
74 cl::init(Val: ""));
75
76cl::opt<bool> AppendProgramExitCode(
77 "append-exit-code",
78 cl::desc("Append the exit code to the output so it gets diff'd too"),
79 cl::init(Val: false));
80
81cl::opt<std::string>
82 InputFile("input", cl::init(Val: "/dev/null"),
83 cl::desc("Filename to pipe in as stdin (default: /dev/null)"));
84
85static cl::list<std::string>
86 AdditionalSOs("additional-so", cl::desc("Additional shared objects to load "
87 "into executing programs"));
88
89static cl::list<std::string> AdditionalLinkerArgs(
90 "Xlinker", cl::desc("Additional arguments to pass to the linker"));
91
92cl::opt<std::string> CustomCompileCommand(
93 "compile-command", cl::init(Val: "llc"),
94 cl::desc("Command to compile the bitcode (use with -compile-custom) "
95 "(default: llc)"));
96
97cl::opt<std::string> CustomExecCommand(
98 "exec-command", cl::init(Val: "simulate"),
99 cl::desc("Command to execute the bitcode (use with -run-custom) "
100 "(default: simulate)"));
101}
102
103namespace llvm {
104// Anything specified after the --args option are taken as arguments to the
105// program being debugged.
106cl::list<std::string> InputArgv("args", cl::Positional,
107 cl::desc("<program arguments>..."),
108 cl::PositionalEatsArgs);
109
110cl::opt<std::string>
111 OutputPrefix("output-prefix", cl::init(Val: "bugpoint"),
112 cl::desc("Prefix to use for outputs (default: 'bugpoint')"));
113}
114
115namespace {
116cl::list<std::string> ToolArgv("tool-args", cl::Positional,
117 cl::desc("<tool arguments>..."),
118 cl::PositionalEatsArgs);
119
120cl::list<std::string> SafeToolArgv("safe-tool-args", cl::Positional,
121 cl::desc("<safe-tool arguments>..."),
122 cl::PositionalEatsArgs);
123
124cl::opt<std::string> CCBinary("gcc", cl::init(Val: ""),
125 cl::desc("The gcc binary to use."));
126
127cl::list<std::string> CCToolArgv("gcc-tool-args", cl::Positional,
128 cl::desc("<gcc-tool arguments>..."),
129 cl::PositionalEatsArgs);
130}
131
132//===----------------------------------------------------------------------===//
133// BugDriver method implementation
134//
135
136/// initializeExecutionEnvironment - This method is used to set up the
137/// environment for executing LLVM programs.
138///
139Error BugDriver::initializeExecutionEnvironment() {
140 outs() << "Initializing execution environment: ";
141
142 // Create an instance of the AbstractInterpreter interface as specified on
143 // the command line
144 SafeInterpreter = nullptr;
145 std::string Message;
146
147 if (CCBinary.empty()) {
148 if (ErrorOr<std::string> ClangPath =
149 FindProgramByName(ExeName: "clang", Argv0: getToolName(), MainAddr: &AbsTolerance))
150 CCBinary = *ClangPath;
151 else
152 CCBinary = "gcc";
153 }
154
155 switch (InterpreterSel) {
156 case AutoPick:
157 if (!Interpreter) {
158 InterpreterSel = RunJIT;
159 Interpreter =
160 AbstractInterpreter::createJIT(Argv0: getToolName(), Message, Args: &ToolArgv);
161 }
162 if (!Interpreter) {
163 InterpreterSel = RunLLC;
164 Interpreter = AbstractInterpreter::createLLC(
165 Argv0: getToolName(), Message, CCBinary, Args: &ToolArgv, CCArgs: &CCToolArgv);
166 }
167 if (!Interpreter) {
168 InterpreterSel = RunLLI;
169 Interpreter =
170 AbstractInterpreter::createLLI(Argv0: getToolName(), Message, Args: &ToolArgv);
171 }
172 if (!Interpreter) {
173 InterpreterSel = AutoPick;
174 Message = "Sorry, I can't automatically select an interpreter!\n";
175 }
176 break;
177 case RunLLI:
178 Interpreter =
179 AbstractInterpreter::createLLI(Argv0: getToolName(), Message, Args: &ToolArgv);
180 break;
181 case RunLLC:
182 case RunLLCIA:
183 Interpreter = AbstractInterpreter::createLLC(
184 Argv0: getToolName(), Message, CCBinary, Args: &ToolArgv, CCArgs: &CCToolArgv,
185 UseIntegratedAssembler: InterpreterSel == RunLLCIA);
186 break;
187 case RunJIT:
188 Interpreter =
189 AbstractInterpreter::createJIT(Argv0: getToolName(), Message, Args: &ToolArgv);
190 break;
191 case CompileCustom:
192 Interpreter = AbstractInterpreter::createCustomCompiler(
193 Argv0: getToolName(), Message, CompileCommandLine: CustomCompileCommand);
194 break;
195 case Custom:
196 Interpreter = AbstractInterpreter::createCustomExecutor(
197 Argv0: getToolName(), Message, ExecCommandLine: CustomExecCommand);
198 break;
199 }
200 if (!Interpreter)
201 errs() << Message;
202 else // Display informational messages on stdout instead of stderr
203 outs() << Message;
204
205 std::string Path = SafeInterpreterPath;
206 if (Path.empty())
207 Path = getToolName();
208 std::vector<std::string> SafeToolArgs = SafeToolArgv;
209 switch (SafeInterpreterSel) {
210 case AutoPick:
211 // In "llc-safe" mode, default to using LLC as the "safe" backend.
212 if (InterpreterSel == RunLLC) {
213 SafeInterpreterSel = RunLLC;
214 SafeToolArgs.push_back(x: "--relocation-model=pic");
215 SafeInterpreter = AbstractInterpreter::createLLC(
216 Argv0: Path.c_str(), Message, CCBinary, Args: &SafeToolArgs, CCArgs: &CCToolArgv);
217 } else if (InterpreterSel != CompileCustom) {
218 SafeInterpreterSel = AutoPick;
219 Message = "Sorry, I can't automatically select a safe interpreter!\n";
220 }
221 break;
222 case RunLLC:
223 case RunLLCIA:
224 SafeToolArgs.push_back(x: "--relocation-model=pic");
225 SafeInterpreter = AbstractInterpreter::createLLC(
226 Argv0: Path.c_str(), Message, CCBinary, Args: &SafeToolArgs, CCArgs: &CCToolArgv,
227 UseIntegratedAssembler: SafeInterpreterSel == RunLLCIA);
228 break;
229 case Custom:
230 SafeInterpreter = AbstractInterpreter::createCustomExecutor(
231 Argv0: getToolName(), Message, ExecCommandLine: CustomExecCommand);
232 break;
233 default:
234 Message = "Sorry, this back-end is not supported by bugpoint as the "
235 "\"safe\" backend right now!\n";
236 break;
237 }
238 if (!SafeInterpreter && InterpreterSel != CompileCustom) {
239 outs() << Message << "\nExiting.\n";
240 exit(status: 1);
241 }
242
243 cc = CC::create(Argv0: getToolName(), Message, CCBinary, Args: &CCToolArgv);
244 if (!cc) {
245 outs() << Message << "\nExiting.\n";
246 exit(status: 1);
247 }
248
249 // If there was an error creating the selected interpreter, quit with error.
250 if (Interpreter == nullptr)
251 return make_error<StringError>(Args: "Failed to init execution environment",
252 Args: inconvertibleErrorCode());
253 return Error::success();
254}
255
256/// Try to compile the specified module, returning false and setting Error if an
257/// error occurs. This is used for code generation crash testing.
258Error BugDriver::compileProgram(Module &M) const {
259 // Emit the program to a bitcode file...
260 auto Temp =
261 sys::fs::TempFile::create(Model: OutputPrefix + "-test-program-%%%%%%%.bc");
262 if (!Temp) {
263 errs() << ToolName
264 << ": Error making unique filename: " << toString(E: Temp.takeError())
265 << "\n";
266 exit(status: 1);
267 }
268 DiscardTemp Discard{.File: *Temp};
269 if (writeProgramToFile(FD: Temp->FD, M)) {
270 errs() << ToolName << ": Error emitting bitcode to file '" << Temp->TmpName
271 << "'!\n";
272 exit(status: 1);
273 }
274
275 // Actually compile the program!
276 return Interpreter->compileProgram(Bitcode: Temp->TmpName, Timeout, MemoryLimit);
277}
278
279/// This method runs "Program", capturing the output of the program to a file,
280/// returning the filename of the file. A recommended filename may be
281/// optionally specified.
282Expected<std::string> BugDriver::executeProgram(const Module &Program,
283 std::string OutputFile,
284 std::string BitcodeFile,
285 const std::string &SharedObj,
286 AbstractInterpreter *AI) const {
287 if (!AI)
288 AI = Interpreter;
289 assert(AI && "Interpreter should have been created already!");
290 bool CreatedBitcode = false;
291 if (BitcodeFile.empty()) {
292 // Emit the program to a bitcode file...
293 SmallString<128> UniqueFilename;
294 int UniqueFD;
295 std::error_code EC = sys::fs::createUniqueFile(
296 Model: OutputPrefix + "-test-program-%%%%%%%.bc", ResultFD&: UniqueFD, ResultPath&: UniqueFilename);
297 if (EC) {
298 errs() << ToolName << ": Error making unique filename: " << EC.message()
299 << "!\n";
300 exit(status: 1);
301 }
302 BitcodeFile = std::string(UniqueFilename);
303
304 if (writeProgramToFile(Filename: BitcodeFile, FD: UniqueFD, M: Program)) {
305 errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
306 << "'!\n";
307 exit(status: 1);
308 }
309 CreatedBitcode = true;
310 }
311
312 // Remove the temporary bitcode file when we are done.
313 std::string BitcodePath(BitcodeFile);
314 FileRemover BitcodeFileRemover(BitcodePath, CreatedBitcode && !SaveTemps);
315
316 if (OutputFile.empty())
317 OutputFile = OutputPrefix + "-execution-output-%%%%%%%";
318
319 // Check to see if this is a valid output filename...
320 SmallString<128> UniqueFile;
321 std::error_code EC = sys::fs::createUniqueFile(Model: OutputFile, ResultPath&: UniqueFile);
322 if (EC) {
323 errs() << ToolName << ": Error making unique filename: " << EC.message()
324 << "\n";
325 exit(status: 1);
326 }
327 OutputFile = std::string(UniqueFile);
328
329 // Figure out which shared objects to run, if any.
330 std::vector<std::string> SharedObjs(AdditionalSOs);
331 if (!SharedObj.empty())
332 SharedObjs.push_back(x: SharedObj);
333
334 Expected<int> RetVal = AI->ExecuteProgram(Bitcode: BitcodeFile, Args: InputArgv, InputFile,
335 OutputFile, CCArgs: AdditionalLinkerArgs,
336 SharedLibs: SharedObjs, Timeout, MemoryLimit);
337 if (Error E = RetVal.takeError())
338 return std::move(E);
339
340 if (*RetVal == -1) {
341 errs() << "<timeout>";
342 static bool FirstTimeout = true;
343 if (FirstTimeout) {
344 outs()
345 << "\n"
346 "*** Program execution timed out! This mechanism is designed to "
347 "handle\n"
348 " programs stuck in infinite loops gracefully. The -timeout "
349 "option\n"
350 " can be used to change the timeout threshold or disable it "
351 "completely\n"
352 " (with -timeout=0). This message is only displayed once.\n";
353 FirstTimeout = false;
354 }
355 }
356
357 if (AppendProgramExitCode) {
358 std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
359 outFile << "exit " << *RetVal << '\n';
360 outFile.close();
361 }
362
363 // Return the filename we captured the output to.
364 return OutputFile;
365}
366
367/// Used to create reference output with the "safe" backend, if reference output
368/// is not provided.
369Expected<std::string>
370BugDriver::executeProgramSafely(const Module &Program,
371 const std::string &OutputFile) const {
372 return executeProgram(Program, OutputFile, BitcodeFile: "", SharedObj: "", AI: SafeInterpreter);
373}
374
375Expected<std::string>
376BugDriver::compileSharedObject(const std::string &BitcodeFile) {
377 assert(Interpreter && "Interpreter should have been created already!");
378 std::string OutputFile;
379
380 // Using the known-good backend.
381 Expected<CC::FileType> FT =
382 SafeInterpreter->OutputCode(Bitcode: BitcodeFile, OutFile&: OutputFile);
383 if (Error E = FT.takeError())
384 return std::move(E);
385
386 std::string SharedObjectFile;
387 if (Error E = cc->MakeSharedObject(InputFile: OutputFile, fileType: *FT, OutputFile&: SharedObjectFile,
388 ArgsForCC: AdditionalLinkerArgs))
389 return std::move(E);
390
391 // Remove the intermediate C file
392 sys::fs::remove(path: OutputFile);
393
394 return SharedObjectFile;
395}
396
397/// Calls compileProgram and then records the output into ReferenceOutputFile.
398/// Returns true if reference file created, false otherwise. Note:
399/// initializeExecutionEnvironment should be called BEFORE this function.
400Error BugDriver::createReferenceFile(Module &M, const std::string &Filename) {
401 if (Error E = compileProgram(M&: *Program))
402 return E;
403
404 Expected<std::string> Result = executeProgramSafely(Program: *Program, OutputFile: Filename);
405 if (Error E = Result.takeError()) {
406 if (Interpreter != SafeInterpreter) {
407 E = joinErrors(
408 E1: std::move(E),
409 E2: make_error<StringError>(
410 Args: "*** There is a bug running the \"safe\" backend. Either"
411 " debug it (for example with the -run-jit bugpoint option,"
412 " if JIT is being used as the \"safe\" backend), or fix the"
413 " error some other way.\n",
414 Args: inconvertibleErrorCode()));
415 }
416 return E;
417 }
418 ReferenceOutputFile = *Result;
419 outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
420 return Error::success();
421}
422
423/// This method executes the specified module and diffs the output against the
424/// file specified by ReferenceOutputFile. If the output is different, 1 is
425/// returned. If there is a problem with the code generator (e.g., llc
426/// crashes), this will set ErrMsg.
427Expected<bool> BugDriver::diffProgram(const Module &Program,
428 const std::string &BitcodeFile,
429 const std::string &SharedObject,
430 bool RemoveBitcode) const {
431 // Execute the program, generating an output file...
432 Expected<std::string> Output =
433 executeProgram(Program, OutputFile: "", BitcodeFile, SharedObj: SharedObject, AI: nullptr);
434 if (Error E = Output.takeError())
435 return std::move(E);
436
437 std::string Error;
438 bool FilesDifferent = false;
439 if (int Diff = DiffFilesWithTolerance(FileA: ReferenceOutputFile, FileB: *Output,
440 AbsTol: AbsTolerance, RelTol: RelTolerance, Error: &Error)) {
441 if (Diff == 2) {
442 errs() << "While diffing output: " << Error << '\n';
443 exit(status: 1);
444 }
445 FilesDifferent = true;
446 } else {
447 // Remove the generated output if there are no differences.
448 sys::fs::remove(path: *Output);
449 }
450
451 // Remove the bitcode file if we are supposed to.
452 if (RemoveBitcode)
453 sys::fs::remove(path: BitcodeFile);
454 return FilesDifferent;
455}
456
457bool BugDriver::isExecutingJIT() { return InterpreterSel == RunJIT; }
458