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
25using namespace llvm;
26
27namespace {
28  // OutputType - Allow the user to specify the way code should be run, to test
29  // for miscompilation.
30  //
31  enum OutputType {
32    AutoPick, RunLLI, RunJIT, RunLLC, RunLLCIA, LLC_Safe, CompileCustom, Custom
33  };
34
35  cl::opt<double>
36  AbsTolerance("abs-tolerance", cl::desc("Absolute error tolerated"),
37               cl::init(0.0));
38  cl::opt<double>
39  RelTolerance("rel-tolerance", cl::desc("Relative error tolerated"),
40               cl::init(0.0));
41
42  cl::opt<OutputType>
43  InterpreterSel(cl::desc("Specify the \"test\" i.e. suspect back-end:"),
44                 cl::values(clEnumValN(AutoPick, "auto", "Use best guess"),
45                            clEnumValN(RunLLI, "run-int",
46                                       "Execute with the interpreter"),
47                            clEnumValN(RunJIT, "run-jit", "Execute with JIT"),
48                            clEnumValN(RunLLC, "run-llc", "Compile with LLC"),
49                            clEnumValN(RunLLCIA, "run-llc-ia",
50                                  "Compile with LLC with integrated assembler"),
51                            clEnumValN(LLC_Safe, "llc-safe", "Use LLC for all"),
52                            clEnumValN(CompileCustom, "compile-custom",
53                            "Use -compile-command to define a command to "
54                            "compile the bitcode. Useful to avoid linking."),
55                            clEnumValN(Custom, "run-custom",
56                            "Use -exec-command to define a command to execute "
57                            "the bitcode. Useful for cross-compilation."),
58                            clEnumValEnd),
59                 cl::init(AutoPick));
60
61  cl::opt<OutputType>
62  SafeInterpreterSel(cl::desc("Specify \"safe\" i.e. known-good backend:"),
63              cl::values(clEnumValN(AutoPick, "safe-auto", "Use best guess"),
64                         clEnumValN(RunLLC, "safe-run-llc", "Compile with LLC"),
65                         clEnumValN(Custom, "safe-run-custom",
66                         "Use -exec-command to define a command to execute "
67                         "the bitcode. Useful for cross-compilation."),
68                         clEnumValEnd),
69                     cl::init(AutoPick));
70
71  cl::opt<std::string>
72  SafeInterpreterPath("safe-path",
73                   cl::desc("Specify the path to the \"safe\" backend program"),
74                   cl::init(""));
75
76  cl::opt<bool>
77  AppendProgramExitCode("append-exit-code",
78      cl::desc("Append the exit code to the output so it gets diff'd too"),
79      cl::init(false));
80
81  cl::opt<std::string>
82  InputFile("input", cl::init("/dev/null"),
83            cl::desc("Filename to pipe in as stdin (default: /dev/null)"));
84
85  cl::list<std::string>
86  AdditionalSOs("additional-so",
87                cl::desc("Additional shared objects to load "
88                         "into executing programs"));
89
90  cl::list<std::string>
91  AdditionalLinkerArgs("Xlinker",
92      cl::desc("Additional arguments to pass to the linker"));
93
94  cl::opt<std::string>
95  CustomCompileCommand("compile-command", cl::init("llc"),
96      cl::desc("Command to compile the bitcode (use with -compile-custom) "
97               "(default: llc)"));
98
99  cl::opt<std::string>
100  CustomExecCommand("exec-command", cl::init("simulate"),
101      cl::desc("Command to execute the bitcode (use with -run-custom) "
102               "(default: simulate)"));
103}
104
105namespace llvm {
106  // Anything specified after the --args option are taken as arguments to the
107  // program being debugged.
108  cl::list<std::string>
109  InputArgv("args", cl::Positional, cl::desc("<program arguments>..."),
110            cl::ZeroOrMore, cl::PositionalEatsArgs);
111
112  cl::opt<std::string>
113  OutputPrefix("output-prefix", cl::init("bugpoint"),
114            cl::desc("Prefix to use for outputs (default: 'bugpoint')"));
115}
116
117namespace {
118  cl::list<std::string>
119  ToolArgv("tool-args", cl::Positional, cl::desc("<tool arguments>..."),
120           cl::ZeroOrMore, cl::PositionalEatsArgs);
121
122  cl::list<std::string>
123  SafeToolArgv("safe-tool-args", cl::Positional,
124               cl::desc("<safe-tool arguments>..."),
125               cl::ZeroOrMore, cl::PositionalEatsArgs);
126
127  cl::opt<std::string>
128  CCBinary("gcc", cl::init(""), cl::desc("The gcc binary to use."));
129
130  cl::list<std::string>
131  CCToolArgv("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///
143bool 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  if (CCBinary.empty()) {
152    if (sys::findProgramByName("clang"))
153      CCBinary = "clang";
154    else
155      CCBinary = "gcc";
156  }
157
158  switch (InterpreterSel) {
159  case AutoPick:
160    if (!Interpreter) {
161      InterpreterSel = RunJIT;
162      Interpreter = AbstractInterpreter::createJIT(getToolName(), Message,
163                                                   &ToolArgv);
164    }
165    if (!Interpreter) {
166      InterpreterSel = RunLLC;
167      Interpreter = AbstractInterpreter::createLLC(getToolName(), Message,
168                                                   CCBinary, &ToolArgv,
169                                                   &CCToolArgv);
170    }
171    if (!Interpreter) {
172      InterpreterSel = RunLLI;
173      Interpreter = AbstractInterpreter::createLLI(getToolName(), Message,
174                                                   &ToolArgv);
175    }
176    if (!Interpreter) {
177      InterpreterSel = AutoPick;
178      Message = "Sorry, I can't automatically select an interpreter!\n";
179    }
180    break;
181  case RunLLI:
182    Interpreter = AbstractInterpreter::createLLI(getToolName(), Message,
183                                                 &ToolArgv);
184    break;
185  case RunLLC:
186  case RunLLCIA:
187  case LLC_Safe:
188    Interpreter = AbstractInterpreter::createLLC(getToolName(), Message,
189                                                 CCBinary, &ToolArgv,
190                                                 &CCToolArgv,
191                                                 InterpreterSel == RunLLCIA);
192    break;
193  case RunJIT:
194    Interpreter = AbstractInterpreter::createJIT(getToolName(), Message,
195                                                 &ToolArgv);
196    break;
197  case CompileCustom:
198    Interpreter =
199      AbstractInterpreter::createCustomCompiler(Message, CustomCompileCommand);
200    break;
201  case Custom:
202    Interpreter =
203      AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
204    break;
205  }
206  if (!Interpreter)
207    errs() << Message;
208  else // Display informational messages on stdout instead of stderr
209    outs() << Message;
210
211  std::string Path = SafeInterpreterPath;
212  if (Path.empty())
213    Path = getToolName();
214  std::vector<std::string> SafeToolArgs = SafeToolArgv;
215  switch (SafeInterpreterSel) {
216  case AutoPick:
217    // In "llc-safe" mode, default to using LLC as the "safe" backend.
218    if (!SafeInterpreter &&
219        InterpreterSel == LLC_Safe) {
220      SafeInterpreterSel = RunLLC;
221      SafeToolArgs.push_back("--relocation-model=pic");
222      SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
223                                                       CCBinary,
224                                                       &SafeToolArgs,
225                                                       &CCToolArgv);
226    }
227
228    if (!SafeInterpreter &&
229        InterpreterSel != RunLLC &&
230        InterpreterSel != RunJIT) {
231      SafeInterpreterSel = RunLLC;
232      SafeToolArgs.push_back("--relocation-model=pic");
233      SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
234                                                       CCBinary,
235                                                       &SafeToolArgs,
236                                                       &CCToolArgv);
237    }
238    if (!SafeInterpreter) {
239      SafeInterpreterSel = AutoPick;
240      Message = "Sorry, I can't automatically select a safe interpreter!\n";
241    }
242    break;
243  case RunLLC:
244  case RunLLCIA:
245    SafeToolArgs.push_back("--relocation-model=pic");
246    SafeInterpreter = AbstractInterpreter::createLLC(Path.c_str(), Message,
247                                                     CCBinary, &SafeToolArgs,
248                                                     &CCToolArgv,
249                                                SafeInterpreterSel == RunLLCIA);
250    break;
251  case Custom:
252    SafeInterpreter =
253      AbstractInterpreter::createCustomExecutor(Message, CustomExecCommand);
254    break;
255  default:
256    Message = "Sorry, this back-end is not supported by bugpoint as the "
257              "\"safe\" backend right now!\n";
258    break;
259  }
260  if (!SafeInterpreter) { outs() << Message << "\nExiting.\n"; exit(1); }
261
262  cc = CC::create(Message, CCBinary, &CCToolArgv);
263  if (!cc) { outs() << Message << "\nExiting.\n"; exit(1); }
264
265  // If there was an error creating the selected interpreter, quit with error.
266  return Interpreter == nullptr;
267}
268
269/// compileProgram - Try to compile the specified module, returning false and
270/// setting Error if an error occurs.  This is used for code generation
271/// crash testing.
272///
273void BugDriver::compileProgram(Module *M, std::string *Error) const {
274  // Emit the program to a bitcode file...
275  SmallString<128> BitcodeFile;
276  int BitcodeFD;
277  std::error_code EC = sys::fs::createUniqueFile(
278      OutputPrefix + "-test-program-%%%%%%%.bc", BitcodeFD, BitcodeFile);
279  if (EC) {
280    errs() << ToolName << ": Error making unique filename: " << EC.message()
281           << "\n";
282    exit(1);
283  }
284  if (writeProgramToFile(BitcodeFile.str(), BitcodeFD, M)) {
285    errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
286           << "'!\n";
287    exit(1);
288  }
289
290  // Remove the temporary bitcode file when we are done.
291  FileRemover BitcodeFileRemover(BitcodeFile.str(), !SaveTemps);
292
293  // Actually compile the program!
294  Interpreter->compileProgram(BitcodeFile.str(), Error, Timeout, MemoryLimit);
295}
296
297
298/// executeProgram - This method runs "Program", capturing the output of the
299/// program to a file, returning the filename of the file.  A recommended
300/// filename may be optionally specified.
301///
302std::string BugDriver::executeProgram(const Module *Program,
303                                      std::string OutputFile,
304                                      std::string BitcodeFile,
305                                      const std::string &SharedObj,
306                                      AbstractInterpreter *AI,
307                                      std::string *Error) const {
308  if (!AI) AI = Interpreter;
309  assert(AI && "Interpreter should have been created already!");
310  bool CreatedBitcode = false;
311  if (BitcodeFile.empty()) {
312    // Emit the program to a bitcode file...
313    SmallString<128> UniqueFilename;
314    int UniqueFD;
315    std::error_code EC = sys::fs::createUniqueFile(
316        OutputPrefix + "-test-program-%%%%%%%.bc", UniqueFD, UniqueFilename);
317    if (EC) {
318      errs() << ToolName << ": Error making unique filename: "
319             << EC.message() << "!\n";
320      exit(1);
321    }
322    BitcodeFile = UniqueFilename.str();
323
324    if (writeProgramToFile(BitcodeFile, UniqueFD, Program)) {
325      errs() << ToolName << ": Error emitting bitcode to file '"
326             << BitcodeFile << "'!\n";
327      exit(1);
328    }
329    CreatedBitcode = true;
330  }
331
332  // Remove the temporary bitcode file when we are done.
333  std::string BitcodePath(BitcodeFile);
334  FileRemover BitcodeFileRemover(BitcodePath,
335    CreatedBitcode && !SaveTemps);
336
337  if (OutputFile.empty()) OutputFile = OutputPrefix + "-execution-output-%%%%%%%";
338
339  // Check to see if this is a valid output filename...
340  SmallString<128> UniqueFile;
341  std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
342  if (EC) {
343    errs() << ToolName << ": Error making unique filename: "
344           << EC.message() << "\n";
345    exit(1);
346  }
347  OutputFile = UniqueFile.str();
348
349  // Figure out which shared objects to run, if any.
350  std::vector<std::string> SharedObjs(AdditionalSOs);
351  if (!SharedObj.empty())
352    SharedObjs.push_back(SharedObj);
353
354  int RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile, OutputFile,
355                                  Error, AdditionalLinkerArgs, SharedObjs,
356                                  Timeout, MemoryLimit);
357  if (!Error->empty())
358    return OutputFile;
359
360  if (RetVal == -1) {
361    errs() << "<timeout>";
362    static bool FirstTimeout = true;
363    if (FirstTimeout) {
364      outs() << "\n"
365 "*** Program execution timed out!  This mechanism is designed to handle\n"
366 "    programs stuck in infinite loops gracefully.  The -timeout option\n"
367 "    can be used to change the timeout threshold or disable it completely\n"
368 "    (with -timeout=0).  This message is only displayed once.\n";
369      FirstTimeout = false;
370    }
371  }
372
373  if (AppendProgramExitCode) {
374    std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
375    outFile << "exit " << RetVal << '\n';
376    outFile.close();
377  }
378
379  // Return the filename we captured the output to.
380  return OutputFile;
381}
382
383/// executeProgramSafely - Used to create reference output with the "safe"
384/// backend, if reference output is not provided.
385///
386std::string BugDriver::executeProgramSafely(const Module *Program,
387                                            std::string OutputFile,
388                                            std::string *Error) const {
389  return executeProgram(Program, OutputFile, "", "", SafeInterpreter, Error);
390}
391
392std::string BugDriver::compileSharedObject(const std::string &BitcodeFile,
393                                           std::string &Error) {
394  assert(Interpreter && "Interpreter should have been created already!");
395  std::string OutputFile;
396
397  // Using the known-good backend.
398  CC::FileType FT = SafeInterpreter->OutputCode(BitcodeFile, OutputFile,
399                                                 Error);
400  if (!Error.empty())
401    return "";
402
403  std::string SharedObjectFile;
404  bool Failure = cc->MakeSharedObject(OutputFile, FT, SharedObjectFile,
405                                       AdditionalLinkerArgs, Error);
406  if (!Error.empty())
407    return "";
408  if (Failure)
409    exit(1);
410
411  // Remove the intermediate C file
412  sys::fs::remove(OutputFile);
413
414  return SharedObjectFile;
415}
416
417/// createReferenceFile - calls compileProgram and then records the output
418/// into ReferenceOutputFile. Returns true if reference file created, false
419/// otherwise. Note: initializeExecutionEnvironment should be called BEFORE
420/// this function.
421///
422bool BugDriver::createReferenceFile(Module *M, const std::string &Filename) {
423  std::string Error;
424  compileProgram(Program, &Error);
425  if (!Error.empty())
426    return false;
427
428  ReferenceOutputFile = executeProgramSafely(Program, Filename, &Error);
429  if (!Error.empty()) {
430    errs() << Error;
431    if (Interpreter != SafeInterpreter) {
432      errs() << "*** There is a bug running the \"safe\" backend.  Either"
433             << " debug it (for example with the -run-jit bugpoint option,"
434             << " if JIT is being used as the \"safe\" backend), or fix the"
435             << " error some other way.\n";
436    }
437    return false;
438  }
439  outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
440  return true;
441}
442
443/// diffProgram - This method executes the specified module and diffs the
444/// output against the file specified by ReferenceOutputFile.  If the output
445/// is different, 1 is returned.  If there is a problem with the code
446/// generator (e.g., llc crashes), this will set ErrMsg.
447///
448bool BugDriver::diffProgram(const Module *Program,
449                            const std::string &BitcodeFile,
450                            const std::string &SharedObject,
451                            bool RemoveBitcode,
452                            std::string *ErrMsg) const {
453  // Execute the program, generating an output file...
454  std::string Output(
455      executeProgram(Program, "", BitcodeFile, SharedObject, nullptr, ErrMsg));
456  if (!ErrMsg->empty())
457    return false;
458
459  std::string Error;
460  bool FilesDifferent = false;
461  if (int Diff = DiffFilesWithTolerance(ReferenceOutputFile,
462                                        Output,
463                                        AbsTolerance, RelTolerance, &Error)) {
464    if (Diff == 2) {
465      errs() << "While diffing output: " << Error << '\n';
466      exit(1);
467    }
468    FilesDifferent = true;
469  }
470  else {
471    // Remove the generated output if there are no differences.
472    sys::fs::remove(Output);
473  }
474
475  // Remove the bitcode file if we are supposed to.
476  if (RemoveBitcode)
477    sys::fs::remove(BitcodeFile);
478  return FilesDifferent;
479}
480
481bool BugDriver::isExecutingJIT() {
482  return InterpreterSel == RunJIT;
483}
484
485