1 //===- ExecutionDriver.cpp - Allow execution of LLVM program --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains code used to execute the program utilizing one of the
11 // various ways of running LLVM bitcode.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "BugDriver.h"
16 #include "ToolRunner.h"
17 #include "llvm/Support/CommandLine.h"
18 #include "llvm/Support/Debug.h"
19 #include "llvm/Support/FileUtilities.h"
20 #include "llvm/Support/Program.h"
21 #include "llvm/Support/SystemUtils.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include <fstream>
24 
25 using namespace llvm;
26 
27 namespace {
28 // OutputType - Allow the user to specify the way code should be run, to test
29 // for miscompilation.
30 //
31 enum OutputType {
32   AutoPick,
33   RunLLI,
34   RunJIT,
35   RunLLC,
36   RunLLCIA,
37   LLC_Safe,
38   CompileCustom,
39   Custom
40 };
41 
42 cl::opt<double> AbsTolerance("abs-tolerance",
43                              cl::desc("Absolute error tolerated"),
44                              cl::init(0.0));
45 cl::opt<double> RelTolerance("rel-tolerance",
46                              cl::desc("Relative error tolerated"),
47                              cl::init(0.0));
48 
49 cl::opt<OutputType> InterpreterSel(
50     cl::desc("Specify the \"test\" i.e. suspect back-end:"),
51     cl::values(clEnumValN(AutoPick, "auto", "Use best guess"),
52                clEnumValN(RunLLI, "run-int", "Execute with the interpreter"),
53                clEnumValN(RunJIT, "run-jit", "Execute with JIT"),
54                clEnumValN(RunLLC, "run-llc", "Compile with LLC"),
55                clEnumValN(RunLLCIA, "run-llc-ia",
56                           "Compile with LLC with integrated assembler"),
57                clEnumValN(LLC_Safe, "llc-safe", "Use LLC for all"),
58                clEnumValN(CompileCustom, "compile-custom",
59                           "Use -compile-command to define a command to "
60                           "compile the bitcode. Useful to avoid linking."),
61                clEnumValN(Custom, "run-custom",
62                           "Use -exec-command to define a command to execute "
63                           "the bitcode. Useful for cross-compilation.")),
64     cl::init(AutoPick));
65 
66 cl::opt<OutputType> SafeInterpreterSel(
67     cl::desc("Specify \"safe\" i.e. known-good backend:"),
68     cl::values(clEnumValN(AutoPick, "safe-auto", "Use best guess"),
69                clEnumValN(RunLLC, "safe-run-llc", "Compile with LLC"),
70                clEnumValN(Custom, "safe-run-custom",
71                           "Use -exec-command to define a command to execute "
72                           "the bitcode. Useful for cross-compilation.")),
73     cl::init(AutoPick));
74 
75 cl::opt<std::string> SafeInterpreterPath(
76     "safe-path", cl::desc("Specify the path to the \"safe\" backend program"),
77     cl::init(""));
78 
79 cl::opt<bool> AppendProgramExitCode(
80     "append-exit-code",
81     cl::desc("Append the exit code to the output so it gets diff'd too"),
82     cl::init(false));
83 
84 cl::opt<std::string>
85     InputFile("input", cl::init("/dev/null"),
86               cl::desc("Filename to pipe in as stdin (default: /dev/null)"));
87 
88 cl::list<std::string>
89     AdditionalSOs("additional-so", cl::desc("Additional shared objects to load "
90                                             "into executing programs"));
91 
92 cl::list<std::string> AdditionalLinkerArgs(
93     "Xlinker", cl::desc("Additional arguments to pass to the linker"));
94 
95 cl::opt<std::string> CustomCompileCommand(
96     "compile-command", cl::init("llc"),
97     cl::desc("Command to compile the bitcode (use with -compile-custom) "
98              "(default: llc)"));
99 
100 cl::opt<std::string> CustomExecCommand(
101     "exec-command", cl::init("simulate"),
102     cl::desc("Command to execute the bitcode (use with -run-custom) "
103              "(default: simulate)"));
104 }
105 
106 namespace llvm {
107 // Anything specified after the --args option are taken as arguments to the
108 // program being debugged.
109 cl::list<std::string> InputArgv("args", cl::Positional,
110                                 cl::desc("<program arguments>..."),
111                                 cl::ZeroOrMore, cl::PositionalEatsArgs);
112 
113 cl::opt<std::string>
114     OutputPrefix("output-prefix", cl::init("bugpoint"),
115                  cl::desc("Prefix to use for outputs (default: 'bugpoint')"));
116 }
117 
118 namespace {
119 cl::list<std::string> ToolArgv("tool-args", cl::Positional,
120                                cl::desc("<tool arguments>..."), cl::ZeroOrMore,
121                                cl::PositionalEatsArgs);
122 
123 cl::list<std::string> SafeToolArgv("safe-tool-args", cl::Positional,
124                                    cl::desc("<safe-tool arguments>..."),
125                                    cl::ZeroOrMore, cl::PositionalEatsArgs);
126 
127 cl::opt<std::string> CCBinary("gcc", cl::init(""),
128                               cl::desc("The gcc binary to use."));
129 
130 cl::list<std::string> CCToolArgv("gcc-tool-args", cl::Positional,
131                                  cl::desc("<gcc-tool arguments>..."),
132                                  cl::ZeroOrMore, cl::PositionalEatsArgs);
133 }
134 
135 //===----------------------------------------------------------------------===//
136 // BugDriver method implementation
137 //
138 
139 /// initializeExecutionEnvironment - This method is used to set up the
140 /// environment for executing LLVM programs.
141 ///
142 Error BugDriver::initializeExecutionEnvironment() {
143   outs() << "Initializing execution environment: ";
144 
145   // Create an instance of the AbstractInterpreter interface as specified on
146   // the command line
147   SafeInterpreter = nullptr;
148   std::string Message;
149 
150   if (CCBinary.empty()) {
151     if (ErrorOr<std::string> ClangPath =
152             FindProgramByName("clang", getToolName(), &AbsTolerance))
153       CCBinary = *ClangPath;
154     else
155       CCBinary = "gcc";
156   }
157 
158   switch (InterpreterSel) {
159   case AutoPick:
160     if (!Interpreter) {
161       InterpreterSel = RunJIT;
162       Interpreter =
163           AbstractInterpreter::createJIT(getToolName(), Message, &ToolArgv);
164     }
165     if (!Interpreter) {
166       InterpreterSel = RunLLC;
167       Interpreter = AbstractInterpreter::createLLC(
168           getToolName(), Message, CCBinary, &ToolArgv, &CCToolArgv);
169     }
170     if (!Interpreter) {
171       InterpreterSel = RunLLI;
172       Interpreter =
173           AbstractInterpreter::createLLI(getToolName(), Message, &ToolArgv);
174     }
175     if (!Interpreter) {
176       InterpreterSel = AutoPick;
177       Message = "Sorry, I can't automatically select an interpreter!\n";
178     }
179     break;
180   case RunLLI:
181     Interpreter =
182         AbstractInterpreter::createLLI(getToolName(), Message, &ToolArgv);
183     break;
184   case RunLLC:
185   case RunLLCIA:
186   case LLC_Safe:
187     Interpreter = AbstractInterpreter::createLLC(
188         getToolName(), Message, CCBinary, &ToolArgv, &CCToolArgv,
189         InterpreterSel == RunLLCIA);
190     break;
191   case RunJIT:
192     Interpreter =
193         AbstractInterpreter::createJIT(getToolName(), Message, &ToolArgv);
194     break;
195   case CompileCustom:
196     Interpreter = AbstractInterpreter::createCustomCompiler(
197         getToolName(), Message, CustomCompileCommand);
198     break;
199   case Custom:
200     Interpreter = AbstractInterpreter::createCustomExecutor(
201         getToolName(), Message, CustomExecCommand);
202     break;
203   }
204   if (!Interpreter)
205     errs() << Message;
206   else // Display informational messages on stdout instead of stderr
207     outs() << Message;
208 
209   std::string Path = SafeInterpreterPath;
210   if (Path.empty())
211     Path = getToolName();
212   std::vector<std::string> SafeToolArgs = SafeToolArgv;
213   switch (SafeInterpreterSel) {
214   case AutoPick:
215     // In "llc-safe" mode, default to using LLC as the "safe" backend.
216     if (!SafeInterpreter && InterpreterSel == LLC_Safe) {
217       SafeInterpreterSel = RunLLC;
218       SafeToolArgs.push_back("--relocation-model=pic");
219       SafeInterpreter = AbstractInterpreter::createLLC(
220           Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv);
221     }
222 
223     if (!SafeInterpreter && InterpreterSel != RunLLC &&
224         InterpreterSel != RunJIT) {
225       SafeInterpreterSel = RunLLC;
226       SafeToolArgs.push_back("--relocation-model=pic");
227       SafeInterpreter = AbstractInterpreter::createLLC(
228           Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv);
229     }
230     if (!SafeInterpreter) {
231       SafeInterpreterSel = AutoPick;
232       Message = "Sorry, I can't automatically select a safe interpreter!\n";
233     }
234     break;
235   case RunLLC:
236   case RunLLCIA:
237     SafeToolArgs.push_back("--relocation-model=pic");
238     SafeInterpreter = AbstractInterpreter::createLLC(
239         Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv,
240         SafeInterpreterSel == RunLLCIA);
241     break;
242   case Custom:
243     SafeInterpreter = AbstractInterpreter::createCustomExecutor(
244         getToolName(), Message, CustomExecCommand);
245     break;
246   default:
247     Message = "Sorry, this back-end is not supported by bugpoint as the "
248               "\"safe\" backend right now!\n";
249     break;
250   }
251   if (!SafeInterpreter) {
252     outs() << Message << "\nExiting.\n";
253     exit(1);
254   }
255 
256   cc = CC::create(getToolName(), Message, CCBinary, &CCToolArgv);
257   if (!cc) {
258     outs() << Message << "\nExiting.\n";
259     exit(1);
260   }
261 
262   // If there was an error creating the selected interpreter, quit with error.
263   if (Interpreter == nullptr)
264     return make_error<StringError>("Failed to init execution environment",
265                                    inconvertibleErrorCode());
266   return Error::success();
267 }
268 
269 /// Try to compile the specified module, returning false and setting Error if an
270 /// error occurs.  This is used for code generation crash testing.
271 Error BugDriver::compileProgram(Module &M) const {
272   // Emit the program to a bitcode file...
273   auto Temp =
274       sys::fs::TempFile::create(OutputPrefix + "-test-program-%%%%%%%.bc");
275   if (!Temp) {
276     errs() << ToolName
277            << ": Error making unique filename: " << toString(Temp.takeError())
278            << "\n";
279     exit(1);
280   }
281   DiscardTemp Discard{*Temp};
282   if (writeProgramToFile(Temp->FD, M)) {
283     errs() << ToolName << ": Error emitting bitcode to file '" << Temp->TmpName
284            << "'!\n";
285     exit(1);
286   }
287 
288   // Actually compile the program!
289   return Interpreter->compileProgram(Temp->TmpName, Timeout, MemoryLimit);
290 }
291 
292 /// This method runs "Program", capturing the output of the program to a file,
293 /// returning the filename of the file.  A recommended filename may be
294 /// optionally specified.
295 Expected<std::string> BugDriver::executeProgram(const Module &Program,
296                                                 std::string OutputFile,
297                                                 std::string BitcodeFile,
298                                                 const std::string &SharedObj,
299                                                 AbstractInterpreter *AI) const {
300   if (!AI)
301     AI = Interpreter;
302   assert(AI && "Interpreter should have been created already!");
303   bool CreatedBitcode = false;
304   if (BitcodeFile.empty()) {
305     // Emit the program to a bitcode file...
306     SmallString<128> UniqueFilename;
307     int UniqueFD;
308     std::error_code EC = sys::fs::createUniqueFile(
309         OutputPrefix + "-test-program-%%%%%%%.bc", UniqueFD, UniqueFilename);
310     if (EC) {
311       errs() << ToolName << ": Error making unique filename: " << EC.message()
312              << "!\n";
313       exit(1);
314     }
315     BitcodeFile = UniqueFilename.str();
316 
317     if (writeProgramToFile(BitcodeFile, UniqueFD, Program)) {
318       errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
319              << "'!\n";
320       exit(1);
321     }
322     CreatedBitcode = true;
323   }
324 
325   // Remove the temporary bitcode file when we are done.
326   std::string BitcodePath(BitcodeFile);
327   FileRemover BitcodeFileRemover(BitcodePath, CreatedBitcode && !SaveTemps);
328 
329   if (OutputFile.empty())
330     OutputFile = OutputPrefix + "-execution-output-%%%%%%%";
331 
332   // Check to see if this is a valid output filename...
333   SmallString<128> UniqueFile;
334   std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
335   if (EC) {
336     errs() << ToolName << ": Error making unique filename: " << EC.message()
337            << "\n";
338     exit(1);
339   }
340   OutputFile = UniqueFile.str();
341 
342   // Figure out which shared objects to run, if any.
343   std::vector<std::string> SharedObjs(AdditionalSOs);
344   if (!SharedObj.empty())
345     SharedObjs.push_back(SharedObj);
346 
347   Expected<int> RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile,
348                                             OutputFile, AdditionalLinkerArgs,
349                                             SharedObjs, Timeout, MemoryLimit);
350   if (Error E = RetVal.takeError())
351     return std::move(E);
352 
353   if (*RetVal == -1) {
354     errs() << "<timeout>";
355     static bool FirstTimeout = true;
356     if (FirstTimeout) {
357       outs()
358           << "\n"
359              "*** Program execution timed out!  This mechanism is designed to "
360              "handle\n"
361              "    programs stuck in infinite loops gracefully.  The -timeout "
362              "option\n"
363              "    can be used to change the timeout threshold or disable it "
364              "completely\n"
365              "    (with -timeout=0).  This message is only displayed once.\n";
366       FirstTimeout = false;
367     }
368   }
369 
370   if (AppendProgramExitCode) {
371     std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
372     outFile << "exit " << *RetVal << '\n';
373     outFile.close();
374   }
375 
376   // Return the filename we captured the output to.
377   return OutputFile;
378 }
379 
380 /// Used to create reference output with the "safe" backend, if reference output
381 /// is not provided.
382 Expected<std::string>
383 BugDriver::executeProgramSafely(const Module &Program,
384                                 const std::string &OutputFile) const {
385   return executeProgram(Program, OutputFile, "", "", SafeInterpreter);
386 }
387 
388 Expected<std::string>
389 BugDriver::compileSharedObject(const std::string &BitcodeFile) {
390   assert(Interpreter && "Interpreter should have been created already!");
391   std::string OutputFile;
392 
393   // Using the known-good backend.
394   Expected<CC::FileType> FT =
395       SafeInterpreter->OutputCode(BitcodeFile, OutputFile);
396   if (Error E = FT.takeError())
397     return std::move(E);
398 
399   std::string SharedObjectFile;
400   if (Error E = cc->MakeSharedObject(OutputFile, *FT, SharedObjectFile,
401                                      AdditionalLinkerArgs))
402     return std::move(E);
403 
404   // Remove the intermediate C file
405   sys::fs::remove(OutputFile);
406 
407   return SharedObjectFile;
408 }
409 
410 /// Calls compileProgram and then records the output into ReferenceOutputFile.
411 /// Returns true if reference file created, false otherwise. Note:
412 /// initializeExecutionEnvironment should be called BEFORE this function.
413 Error BugDriver::createReferenceFile(Module &M, const std::string &Filename) {
414   if (Error E = compileProgram(*Program))
415     return E;
416 
417   Expected<std::string> Result = executeProgramSafely(*Program, Filename);
418   if (Error E = Result.takeError()) {
419     if (Interpreter != SafeInterpreter) {
420       E = joinErrors(
421               std::move(E),
422               make_error<StringError>(
423                   "*** There is a bug running the \"safe\" backend.  Either"
424                   " debug it (for example with the -run-jit bugpoint option,"
425                   " if JIT is being used as the \"safe\" backend), or fix the"
426                   " error some other way.\n",
427                   inconvertibleErrorCode()));
428     }
429     return E;
430   }
431   ReferenceOutputFile = *Result;
432   outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
433   return Error::success();
434 }
435 
436 /// This method executes the specified module and diffs the output against the
437 /// file specified by ReferenceOutputFile.  If the output is different, 1 is
438 /// returned.  If there is a problem with the code generator (e.g., llc
439 /// crashes), this will set ErrMsg.
440 Expected<bool> BugDriver::diffProgram(const Module &Program,
441                                       const std::string &BitcodeFile,
442                                       const std::string &SharedObject,
443                                       bool RemoveBitcode) const {
444   // Execute the program, generating an output file...
445   Expected<std::string> Output =
446       executeProgram(Program, "", BitcodeFile, SharedObject, nullptr);
447   if (Error E = Output.takeError())
448     return std::move(E);
449 
450   std::string Error;
451   bool FilesDifferent = false;
452   if (int Diff = DiffFilesWithTolerance(ReferenceOutputFile, *Output,
453                                         AbsTolerance, RelTolerance, &Error)) {
454     if (Diff == 2) {
455       errs() << "While diffing output: " << Error << '\n';
456       exit(1);
457     }
458     FilesDifferent = true;
459   } else {
460     // Remove the generated output if there are no differences.
461     sys::fs::remove(*Output);
462   }
463 
464   // Remove the bitcode file if we are supposed to.
465   if (RemoveBitcode)
466     sys::fs::remove(BitcodeFile);
467   return FilesDifferent;
468 }
469 
470 bool BugDriver::isExecutingJIT() { return InterpreterSel == RunJIT; }
471