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
24using namespace llvm;
25
26namespace {
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
104namespace 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
116namespace {
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///
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  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///
266void 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///
295std::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///
379std::string BugDriver::executeProgramSafely(const Module *Program,
380                                            std::string OutputFile,
381                                            std::string *Error) const {
382  return executeProgram(Program, OutputFile, "", "", SafeInterpreter, Error);
383}
384
385std::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///
415bool 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///
441bool 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
474bool BugDriver::isExecutingJIT() {
475  return InterpreterSel == RunJIT;
476}
477
478