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/SystemUtils.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <fstream>
23 
24 using namespace llvm;
25 
26 namespace {
27   // OutputType - Allow the user to specify the way code should be run, to test
28   // for miscompilation.
29   //
30   enum OutputType {
31     AutoPick, RunLLI, RunJIT, RunLLC, RunLLCIA, LLC_Safe, CompileCustom, Custom
32   };
33 
34   cl::opt<double>
35   AbsTolerance("abs-tolerance", cl::desc("Absolute error tolerated"),
36                cl::init(0.0));
37   cl::opt<double>
38   RelTolerance("rel-tolerance", cl::desc("Relative error tolerated"),
39                cl::init(0.0));
40 
41   cl::opt<OutputType>
42   InterpreterSel(cl::desc("Specify the \"test\" i.e. suspect back-end:"),
43                  cl::values(clEnumValN(AutoPick, "auto", "Use best guess"),
44                             clEnumValN(RunLLI, "run-int",
45                                        "Execute with the interpreter"),
46                             clEnumValN(RunJIT, "run-jit", "Execute with JIT"),
47                             clEnumValN(RunLLC, "run-llc", "Compile with LLC"),
48                             clEnumValN(RunLLCIA, "run-llc-ia",
49                                   "Compile with LLC with integrated assembler"),
50                             clEnumValN(LLC_Safe, "llc-safe", "Use LLC for all"),
51                             clEnumValN(CompileCustom, "compile-custom",
52                             "Use -compile-command to define a command to "
53                             "compile the bitcode. Useful to avoid linking."),
54                             clEnumValN(Custom, "run-custom",
55                             "Use -exec-command to define a command to execute "
56                             "the bitcode. Useful for cross-compilation."),
57                             clEnumValEnd),
58                  cl::init(AutoPick));
59 
60   cl::opt<OutputType>
61   SafeInterpreterSel(cl::desc("Specify \"safe\" i.e. known-good backend:"),
62               cl::values(clEnumValN(AutoPick, "safe-auto", "Use best guess"),
63                          clEnumValN(RunLLC, "safe-run-llc", "Compile with LLC"),
64                          clEnumValN(Custom, "safe-run-custom",
65                          "Use -exec-command to define a command to execute "
66                          "the bitcode. Useful for cross-compilation."),
67                          clEnumValEnd),
68                      cl::init(AutoPick));
69 
70   cl::opt<std::string>
71   SafeInterpreterPath("safe-path",
72                    cl::desc("Specify the path to the \"safe\" backend program"),
73                    cl::init(""));
74 
75   cl::opt<bool>
76   AppendProgramExitCode("append-exit-code",
77       cl::desc("Append the exit code to the output so it gets diff'd too"),
78       cl::init(false));
79 
80   cl::opt<std::string>
81   InputFile("input", cl::init("/dev/null"),
82             cl::desc("Filename to pipe in as stdin (default: /dev/null)"));
83 
84   cl::list<std::string>
85   AdditionalSOs("additional-so",
86                 cl::desc("Additional shared objects to load "
87                          "into executing programs"));
88 
89   cl::list<std::string>
90   AdditionalLinkerArgs("Xlinker",
91       cl::desc("Additional arguments to pass to the linker"));
92 
93   cl::opt<std::string>
94   CustomCompileCommand("compile-command", cl::init("llc"),
95       cl::desc("Command to compile the bitcode (use with -compile-custom) "
96                "(default: llc)"));
97 
98   cl::opt<std::string>
99   CustomExecCommand("exec-command", cl::init("simulate"),
100       cl::desc("Command to execute the bitcode (use with -run-custom) "
101                "(default: simulate)"));
102 }
103 
104 namespace llvm {
105   // Anything specified after the --args option are taken as arguments to the
106   // program being debugged.
107   cl::list<std::string>
108   InputArgv("args", cl::Positional, cl::desc("<program arguments>..."),
109             cl::ZeroOrMore, cl::PositionalEatsArgs);
110 
111   cl::opt<std::string>
112   OutputPrefix("output-prefix", cl::init("bugpoint"),
113             cl::desc("Prefix to use for outputs (default: 'bugpoint')"));
114 }
115 
116 namespace {
117   cl::list<std::string>
118   ToolArgv("tool-args", cl::Positional, cl::desc("<tool arguments>..."),
119            cl::ZeroOrMore, cl::PositionalEatsArgs);
120 
121   cl::list<std::string>
122   SafeToolArgv("safe-tool-args", cl::Positional,
123                cl::desc("<safe-tool arguments>..."),
124                cl::ZeroOrMore, cl::PositionalEatsArgs);
125 
126   cl::opt<std::string>
127   GCCBinary("gcc", cl::init("gcc"),
128               cl::desc("The gcc binary to use. (default 'gcc')"));
129 
130   cl::list<std::string>
131   GCCToolArgv("gcc-tool-args", cl::Positional,
132               cl::desc("<gcc-tool arguments>..."),
133               cl::ZeroOrMore, cl::PositionalEatsArgs);
134 }
135 
136 //===----------------------------------------------------------------------===//
137 // BugDriver method implementation
138 //
139 
140 /// initializeExecutionEnvironment - This method is used to set up the
141 /// environment for executing LLVM programs.
142 ///
initializeExecutionEnvironment()143 bool BugDriver::initializeExecutionEnvironment() {
144   outs() << "Initializing execution environment: ";
145 
146   // Create an instance of the AbstractInterpreter interface as specified on
147   // the command line
148   SafeInterpreter = nullptr;
149   std::string Message;
150 
151   switch (InterpreterSel) {
152   case AutoPick:
153     if (!Interpreter) {
154       InterpreterSel = RunJIT;
155       Interpreter = AbstractInterpreter::createJIT(getToolName(), Message,
156                                                    &ToolArgv);
157     }
158     if (!Interpreter) {
159       InterpreterSel = RunLLC;
160       Interpreter = AbstractInterpreter::createLLC(getToolName(), Message,
161                                                    GCCBinary, &ToolArgv,
162                                                    &GCCToolArgv);
163     }
164     if (!Interpreter) {
165       InterpreterSel = RunLLI;
166       Interpreter = AbstractInterpreter::createLLI(getToolName(), Message,
167                                                    &ToolArgv);
168     }
169     if (!Interpreter) {
170       InterpreterSel = AutoPick;
171       Message = "Sorry, I can't automatically select an interpreter!\n";
172     }
173     break;
174   case RunLLI:
175     Interpreter = AbstractInterpreter::createLLI(getToolName(), Message,
176                                                  &ToolArgv);
177     break;
178   case RunLLC:
179   case RunLLCIA:
180   case LLC_Safe:
181     Interpreter = AbstractInterpreter::createLLC(getToolName(), Message,
182                                                  GCCBinary, &ToolArgv,
183                                                  &GCCToolArgv,
184                                                  InterpreterSel == RunLLCIA);
185     break;
186   case RunJIT:
187     Interpreter = AbstractInterpreter::createJIT(getToolName(), Message,
188                                                  &ToolArgv);
189     break;
190   case CompileCustom:
191     Interpreter =
192       AbstractInterpreter::createCustomCompiler(Message, CustomCompileCommand);
193     break;
194   case Custom:
195     Interpreter =
196       AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
197     break;
198   }
199   if (!Interpreter)
200     errs() << Message;
201   else // Display informational messages on stdout instead of stderr
202     outs() << Message;
203 
204   std::string Path = SafeInterpreterPath;
205   if (Path.empty())
206     Path = getToolName();
207   std::vector<std::string> SafeToolArgs = SafeToolArgv;
208   switch (SafeInterpreterSel) {
209   case AutoPick:
210     // In "llc-safe" mode, default to using LLC as the "safe" backend.
211     if (!SafeInterpreter &&
212         InterpreterSel == LLC_Safe) {
213       SafeInterpreterSel = RunLLC;
214       SafeToolArgs.push_back("--relocation-model=pic");
215       SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
216                                                        GCCBinary,
217                                                        &SafeToolArgs,
218                                                        &GCCToolArgv);
219     }
220 
221     if (!SafeInterpreter &&
222         InterpreterSel != RunLLC &&
223         InterpreterSel != RunJIT) {
224       SafeInterpreterSel = RunLLC;
225       SafeToolArgs.push_back("--relocation-model=pic");
226       SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
227                                                        GCCBinary,
228                                                        &SafeToolArgs,
229                                                        &GCCToolArgv);
230     }
231     if (!SafeInterpreter) {
232       SafeInterpreterSel = AutoPick;
233       Message = "Sorry, I can't automatically select a safe interpreter!\n";
234     }
235     break;
236   case RunLLC:
237   case RunLLCIA:
238     SafeToolArgs.push_back("--relocation-model=pic");
239     SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
240                                                      GCCBinary, &SafeToolArgs,
241                                                      &GCCToolArgv,
242                                                 SafeInterpreterSel == RunLLCIA);
243     break;
244   case Custom:
245     SafeInterpreter =
246       AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
247     break;
248   default:
249     Message = "Sorry, this back-end is not supported by bugpoint as the "
250               "\"safe\" backend right now!\n";
251     break;
252   }
253   if (!SafeInterpreter) { outs() << Message << "\nExiting.\n"; exit(1); }
254 
255   gcc = GCC::create(Message, GCCBinary, &GCCToolArgv);
256   if (!gcc) { outs() << Message << "\nExiting.\n"; exit(1); }
257 
258   // If there was an error creating the selected interpreter, quit with error.
259   return Interpreter == nullptr;
260 }
261 
262 /// compileProgram - Try to compile the specified module, returning false and
263 /// setting Error if an error occurs.  This is used for code generation
264 /// crash testing.
265 ///
compileProgram(Module * M,std::string * Error) const266 void BugDriver::compileProgram(Module *M, std::string *Error) const {
267   // Emit the program to a bitcode file...
268   SmallString<128> BitcodeFile;
269   int BitcodeFD;
270   std::error_code EC = sys::fs::createUniqueFile(
271       OutputPrefix + "-test-program-%%%%%%%.bc", BitcodeFD, BitcodeFile);
272   if (EC) {
273     errs() << ToolName << ": Error making unique filename: " << EC.message()
274            << "\n";
275     exit(1);
276   }
277   if (writeProgramToFile(BitcodeFile.str(), BitcodeFD, M)) {
278     errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
279            << "'!\n";
280     exit(1);
281   }
282 
283   // Remove the temporary bitcode file when we are done.
284   FileRemover BitcodeFileRemover(BitcodeFile.str(), !SaveTemps);
285 
286   // Actually compile the program!
287   Interpreter->compileProgram(BitcodeFile.str(), Error, Timeout, MemoryLimit);
288 }
289 
290 
291 /// executeProgram - This method runs "Program", capturing the output of the
292 /// program to a file, returning the filename of the file.  A recommended
293 /// filename may be optionally specified.
294 ///
executeProgram(const Module * Program,std::string OutputFile,std::string BitcodeFile,const std::string & SharedObj,AbstractInterpreter * AI,std::string * Error) const295 std::string BugDriver::executeProgram(const Module *Program,
296                                       std::string OutputFile,
297                                       std::string BitcodeFile,
298                                       const std::string &SharedObj,
299                                       AbstractInterpreter *AI,
300                                       std::string *Error) const {
301   if (!AI) 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: "
312              << EC.message() << "!\n";
313       exit(1);
314     }
315     BitcodeFile = UniqueFilename.str();
316 
317     if (writeProgramToFile(BitcodeFile, UniqueFD, Program)) {
318       errs() << ToolName << ": Error emitting bitcode to file '"
319              << BitcodeFile << "'!\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,
328     CreatedBitcode && !SaveTemps);
329 
330   if (OutputFile.empty()) 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: "
337            << EC.message() << "\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   int RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile, OutputFile,
348                                   Error, AdditionalLinkerArgs, SharedObjs,
349                                   Timeout, MemoryLimit);
350   if (!Error->empty())
351     return OutputFile;
352 
353   if (RetVal == -1) {
354     errs() << "<timeout>";
355     static bool FirstTimeout = true;
356     if (FirstTimeout) {
357       outs() << "\n"
358  "*** Program execution timed out!  This mechanism is designed to handle\n"
359  "    programs stuck in infinite loops gracefully.  The -timeout option\n"
360  "    can be used to change the timeout threshold or disable it completely\n"
361  "    (with -timeout=0).  This message is only displayed once.\n";
362       FirstTimeout = false;
363     }
364   }
365 
366   if (AppendProgramExitCode) {
367     std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
368     outFile << "exit " << RetVal << '\n';
369     outFile.close();
370   }
371 
372   // Return the filename we captured the output to.
373   return OutputFile;
374 }
375 
376 /// executeProgramSafely - Used to create reference output with the "safe"
377 /// backend, if reference output is not provided.
378 ///
executeProgramSafely(const Module * Program,std::string OutputFile,std::string * Error) const379 std::string BugDriver::executeProgramSafely(const Module *Program,
380                                             std::string OutputFile,
381                                             std::string *Error) const {
382   return executeProgram(Program, OutputFile, "", "", SafeInterpreter, Error);
383 }
384 
compileSharedObject(const std::string & BitcodeFile,std::string & Error)385 std::string BugDriver::compileSharedObject(const std::string &BitcodeFile,
386                                            std::string &Error) {
387   assert(Interpreter && "Interpreter should have been created already!");
388   std::string OutputFile;
389 
390   // Using the known-good backend.
391   GCC::FileType FT = SafeInterpreter->OutputCode(BitcodeFile, OutputFile,
392                                                  Error);
393   if (!Error.empty())
394     return "";
395 
396   std::string SharedObjectFile;
397   bool Failure = gcc->MakeSharedObject(OutputFile, FT, SharedObjectFile,
398                                        AdditionalLinkerArgs, Error);
399   if (!Error.empty())
400     return "";
401   if (Failure)
402     exit(1);
403 
404   // Remove the intermediate C file
405   sys::fs::remove(OutputFile);
406 
407   return SharedObjectFile;
408 }
409 
410 /// createReferenceFile - calls compileProgram and then records the output
411 /// into ReferenceOutputFile. Returns true if reference file created, false
412 /// otherwise. Note: initializeExecutionEnvironment should be called BEFORE
413 /// this function.
414 ///
createReferenceFile(Module * M,const std::string & Filename)415 bool BugDriver::createReferenceFile(Module *M, const std::string &Filename) {
416   std::string Error;
417   compileProgram(Program, &Error);
418   if (!Error.empty())
419     return false;
420 
421   ReferenceOutputFile = executeProgramSafely(Program, Filename, &Error);
422   if (!Error.empty()) {
423     errs() << Error;
424     if (Interpreter != SafeInterpreter) {
425       errs() << "*** There is a bug running the \"safe\" backend.  Either"
426              << " debug it (for example with the -run-jit bugpoint option,"
427              << " if JIT is being used as the \"safe\" backend), or fix the"
428              << " error some other way.\n";
429     }
430     return false;
431   }
432   outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
433   return true;
434 }
435 
436 /// diffProgram - This method executes the specified module and diffs the
437 /// output against the file specified by ReferenceOutputFile.  If the output
438 /// is different, 1 is returned.  If there is a problem with the code
439 /// generator (e.g., llc crashes), this will set ErrMsg.
440 ///
diffProgram(const Module * Program,const std::string & BitcodeFile,const std::string & SharedObject,bool RemoveBitcode,std::string * ErrMsg) const441 bool BugDriver::diffProgram(const Module *Program,
442                             const std::string &BitcodeFile,
443                             const std::string &SharedObject,
444                             bool RemoveBitcode,
445                             std::string *ErrMsg) const {
446   // Execute the program, generating an output file...
447   std::string Output(
448       executeProgram(Program, "", BitcodeFile, SharedObject, nullptr, ErrMsg));
449   if (!ErrMsg->empty())
450     return false;
451 
452   std::string Error;
453   bool FilesDifferent = false;
454   if (int Diff = DiffFilesWithTolerance(ReferenceOutputFile,
455                                         Output,
456                                         AbsTolerance, RelTolerance, &Error)) {
457     if (Diff == 2) {
458       errs() << "While diffing output: " << Error << '\n';
459       exit(1);
460     }
461     FilesDifferent = true;
462   }
463   else {
464     // Remove the generated output if there are no differences.
465     sys::fs::remove(Output);
466   }
467 
468   // Remove the bitcode file if we are supposed to.
469   if (RemoveBitcode)
470     sys::fs::remove(BitcodeFile);
471   return FilesDifferent;
472 }
473 
isExecutingJIT()474 bool BugDriver::isExecutingJIT() {
475   return InterpreterSel == RunJIT;
476 }
477 
478