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 (sys::findProgramByName("clang"))
152       CCBinary = "clang";
153     else
154       CCBinary = "gcc";
155   }
156 
157   switch (InterpreterSel) {
158   case AutoPick:
159     if (!Interpreter) {
160       InterpreterSel = RunJIT;
161       Interpreter =
162           AbstractInterpreter::createJIT(getToolName(), Message, &ToolArgv);
163     }
164     if (!Interpreter) {
165       InterpreterSel = RunLLC;
166       Interpreter = AbstractInterpreter::createLLC(
167           getToolName(), Message, CCBinary, &ToolArgv, &CCToolArgv);
168     }
169     if (!Interpreter) {
170       InterpreterSel = RunLLI;
171       Interpreter =
172           AbstractInterpreter::createLLI(getToolName(), Message, &ToolArgv);
173     }
174     if (!Interpreter) {
175       InterpreterSel = AutoPick;
176       Message = "Sorry, I can't automatically select an interpreter!\n";
177     }
178     break;
179   case RunLLI:
180     Interpreter =
181         AbstractInterpreter::createLLI(getToolName(), Message, &ToolArgv);
182     break;
183   case RunLLC:
184   case RunLLCIA:
185   case LLC_Safe:
186     Interpreter = AbstractInterpreter::createLLC(
187         getToolName(), Message, CCBinary, &ToolArgv, &CCToolArgv,
188         InterpreterSel == RunLLCIA);
189     break;
190   case RunJIT:
191     Interpreter =
192         AbstractInterpreter::createJIT(getToolName(), Message, &ToolArgv);
193     break;
194   case CompileCustom:
195     Interpreter = AbstractInterpreter::createCustomCompiler(
196         Message, CustomCompileCommand);
197     break;
198   case Custom:
199     Interpreter =
200         AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
201     break;
202   }
203   if (!Interpreter)
204     errs() << Message;
205   else // Display informational messages on stdout instead of stderr
206     outs() << Message;
207 
208   std::string Path = SafeInterpreterPath;
209   if (Path.empty())
210     Path = getToolName();
211   std::vector<std::string> SafeToolArgs = SafeToolArgv;
212   switch (SafeInterpreterSel) {
213   case AutoPick:
214     // In "llc-safe" mode, default to using LLC as the "safe" backend.
215     if (!SafeInterpreter && InterpreterSel == LLC_Safe) {
216       SafeInterpreterSel = RunLLC;
217       SafeToolArgs.push_back("--relocation-model=pic");
218       SafeInterpreter = AbstractInterpreter::createLLC(
219           Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv);
220     }
221 
222     if (!SafeInterpreter && InterpreterSel != RunLLC &&
223         InterpreterSel != RunJIT) {
224       SafeInterpreterSel = RunLLC;
225       SafeToolArgs.push_back("--relocation-model=pic");
226       SafeInterpreter = AbstractInterpreter::createLLC(
227           Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv);
228     }
229     if (!SafeInterpreter) {
230       SafeInterpreterSel = AutoPick;
231       Message = "Sorry, I can't automatically select a safe interpreter!\n";
232     }
233     break;
234   case RunLLC:
235   case RunLLCIA:
236     SafeToolArgs.push_back("--relocation-model=pic");
237     SafeInterpreter = AbstractInterpreter::createLLC(
238         Path.c_str(), Message, CCBinary, &SafeToolArgs, &CCToolArgv,
239         SafeInterpreterSel == RunLLCIA);
240     break;
241   case Custom:
242     SafeInterpreter =
243         AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
244     break;
245   default:
246     Message = "Sorry, this back-end is not supported by bugpoint as the "
247               "\"safe\" backend right now!\n";
248     break;
249   }
250   if (!SafeInterpreter) {
251     outs() << Message << "\nExiting.\n";
252     exit(1);
253   }
254 
255   cc = CC::create(Message, CCBinary, &CCToolArgv);
256   if (!cc) {
257     outs() << Message << "\nExiting.\n";
258     exit(1);
259   }
260 
261   // If there was an error creating the selected interpreter, quit with error.
262   if (Interpreter == nullptr)
263     return make_error<StringError>("Failed to init execution environment",
264                                    inconvertibleErrorCode());
265   return Error::success();
266 }
267 
268 /// compileProgram - Try to compile the specified module, returning false and
269 /// setting Error if an error occurs.  This is used for code generation
270 /// crash testing.
271 ///
272 Error BugDriver::compileProgram(Module *M) const {
273   // Emit the program to a bitcode file...
274   auto Temp =
275       sys::fs::TempFile::create(OutputPrefix + "-test-program-%%%%%%%.bc");
276   if (!Temp) {
277     errs() << ToolName
278            << ": Error making unique filename: " << toString(Temp.takeError())
279            << "\n";
280     exit(1);
281   }
282   DiscardTemp Discard{*Temp};
283   if (writeProgramToFile(Temp->FD, M)) {
284     errs() << ToolName << ": Error emitting bitcode to file '" << Temp->TmpName
285            << "'!\n";
286     exit(1);
287   }
288 
289   // Actually compile the program!
290   return Interpreter->compileProgram(Temp->TmpName, Timeout, MemoryLimit);
291 }
292 
293 /// executeProgram - This method runs "Program", capturing the output of the
294 /// program to a file, returning the filename of the file.  A recommended
295 /// filename may be optionally specified.
296 ///
297 Expected<std::string> BugDriver::executeProgram(const Module *Program,
298                                                 std::string OutputFile,
299                                                 std::string BitcodeFile,
300                                                 const std::string &SharedObj,
301                                                 AbstractInterpreter *AI) const {
302   if (!AI)
303     AI = Interpreter;
304   assert(AI && "Interpreter should have been created already!");
305   bool CreatedBitcode = false;
306   if (BitcodeFile.empty()) {
307     // Emit the program to a bitcode file...
308     SmallString<128> UniqueFilename;
309     int UniqueFD;
310     std::error_code EC = sys::fs::createUniqueFile(
311         OutputPrefix + "-test-program-%%%%%%%.bc", UniqueFD, UniqueFilename);
312     if (EC) {
313       errs() << ToolName << ": Error making unique filename: " << EC.message()
314              << "!\n";
315       exit(1);
316     }
317     BitcodeFile = UniqueFilename.str();
318 
319     if (writeProgramToFile(BitcodeFile, UniqueFD, Program)) {
320       errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
321              << "'!\n";
322       exit(1);
323     }
324     CreatedBitcode = true;
325   }
326 
327   // Remove the temporary bitcode file when we are done.
328   std::string BitcodePath(BitcodeFile);
329   FileRemover BitcodeFileRemover(BitcodePath, CreatedBitcode && !SaveTemps);
330 
331   if (OutputFile.empty())
332     OutputFile = OutputPrefix + "-execution-output-%%%%%%%";
333 
334   // Check to see if this is a valid output filename...
335   SmallString<128> UniqueFile;
336   std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
337   if (EC) {
338     errs() << ToolName << ": Error making unique filename: " << EC.message()
339            << "\n";
340     exit(1);
341   }
342   OutputFile = UniqueFile.str();
343 
344   // Figure out which shared objects to run, if any.
345   std::vector<std::string> SharedObjs(AdditionalSOs);
346   if (!SharedObj.empty())
347     SharedObjs.push_back(SharedObj);
348 
349   Expected<int> RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile,
350                                             OutputFile, AdditionalLinkerArgs,
351                                             SharedObjs, Timeout, MemoryLimit);
352   if (Error E = RetVal.takeError())
353     return std::move(E);
354 
355   if (*RetVal == -1) {
356     errs() << "<timeout>";
357     static bool FirstTimeout = true;
358     if (FirstTimeout) {
359       outs()
360           << "\n"
361              "*** Program execution timed out!  This mechanism is designed to "
362              "handle\n"
363              "    programs stuck in infinite loops gracefully.  The -timeout "
364              "option\n"
365              "    can be used to change the timeout threshold or disable it "
366              "completely\n"
367              "    (with -timeout=0).  This message is only displayed once.\n";
368       FirstTimeout = false;
369     }
370   }
371 
372   if (AppendProgramExitCode) {
373     std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
374     outFile << "exit " << *RetVal << '\n';
375     outFile.close();
376   }
377 
378   // Return the filename we captured the output to.
379   return OutputFile;
380 }
381 
382 /// executeProgramSafely - Used to create reference output with the "safe"
383 /// backend, if reference output is not provided.
384 ///
385 Expected<std::string>
386 BugDriver::executeProgramSafely(const Module *Program,
387                                 const std::string &OutputFile) const {
388   return executeProgram(Program, OutputFile, "", "", SafeInterpreter);
389 }
390 
391 Expected<std::string>
392 BugDriver::compileSharedObject(const std::string &BitcodeFile) {
393   assert(Interpreter && "Interpreter should have been created already!");
394   std::string OutputFile;
395 
396   // Using the known-good backend.
397   Expected<CC::FileType> FT =
398       SafeInterpreter->OutputCode(BitcodeFile, OutputFile);
399   if (Error E = FT.takeError())
400     return std::move(E);
401 
402   std::string SharedObjectFile;
403   if (Error E = cc->MakeSharedObject(OutputFile, *FT, SharedObjectFile,
404                                      AdditionalLinkerArgs))
405     return std::move(E);
406 
407   // Remove the intermediate C file
408   sys::fs::remove(OutputFile);
409 
410   return SharedObjectFile;
411 }
412 
413 /// createReferenceFile - calls compileProgram and then records the output
414 /// into ReferenceOutputFile. Returns true if reference file created, false
415 /// otherwise. Note: initializeExecutionEnvironment should be called BEFORE
416 /// this function.
417 ///
418 Error BugDriver::createReferenceFile(Module *M, const std::string &Filename) {
419   if (Error E = compileProgram(Program))
420     return E;
421 
422   Expected<std::string> Result = executeProgramSafely(Program, Filename);
423   if (Error E = Result.takeError()) {
424     if (Interpreter != SafeInterpreter) {
425       E = joinErrors(
426               std::move(E),
427               make_error<StringError>(
428                   "*** There is a bug running the \"safe\" backend.  Either"
429                   " debug it (for example with the -run-jit bugpoint option,"
430                   " if JIT is being used as the \"safe\" backend), or fix the"
431                   " error some other way.\n",
432                   inconvertibleErrorCode()));
433     }
434     return E;
435   }
436   ReferenceOutputFile = *Result;
437   outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
438   return Error::success();
439 }
440 
441 /// diffProgram - This method executes the specified module and diffs the
442 /// output against the file specified by ReferenceOutputFile.  If the output
443 /// is different, 1 is returned.  If there is a problem with the code
444 /// generator (e.g., llc crashes), this will set ErrMsg.
445 ///
446 Expected<bool> BugDriver::diffProgram(const Module *Program,
447                                       const std::string &BitcodeFile,
448                                       const std::string &SharedObject,
449                                       bool RemoveBitcode) const {
450   // Execute the program, generating an output file...
451   Expected<std::string> Output =
452       executeProgram(Program, "", BitcodeFile, SharedObject, nullptr);
453   if (Error E = Output.takeError())
454     return std::move(E);
455 
456   std::string Error;
457   bool FilesDifferent = false;
458   if (int Diff = DiffFilesWithTolerance(ReferenceOutputFile, *Output,
459                                         AbsTolerance, RelTolerance, &Error)) {
460     if (Diff == 2) {
461       errs() << "While diffing output: " << Error << '\n';
462       exit(1);
463     }
464     FilesDifferent = true;
465   } else {
466     // Remove the generated output if there are no differences.
467     sys::fs::remove(*Output);
468   }
469 
470   // Remove the bitcode file if we are supposed to.
471   if (RemoveBitcode)
472     sys::fs::remove(BitcodeFile);
473   return FilesDifferent;
474 }
475 
476 bool BugDriver::isExecutingJIT() { return InterpreterSel == RunJIT; }
477