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 /// Try to compile the specified module, returning false and setting Error if an
269 /// error occurs.  This is used for code generation crash testing.
270 Error BugDriver::compileProgram(Module &M) const {
271   // Emit the program to a bitcode file...
272   auto Temp =
273       sys::fs::TempFile::create(OutputPrefix + "-test-program-%%%%%%%.bc");
274   if (!Temp) {
275     errs() << ToolName
276            << ": Error making unique filename: " << toString(Temp.takeError())
277            << "\n";
278     exit(1);
279   }
280   DiscardTemp Discard{*Temp};
281   if (writeProgramToFile(Temp->FD, M)) {
282     errs() << ToolName << ": Error emitting bitcode to file '" << Temp->TmpName
283            << "'!\n";
284     exit(1);
285   }
286 
287   // Actually compile the program!
288   return Interpreter->compileProgram(Temp->TmpName, Timeout, MemoryLimit);
289 }
290 
291 /// This method runs "Program", capturing the output of the program to a file,
292 /// returning the filename of the file.  A recommended filename may be
293 /// optionally specified.
294 Expected<std::string> BugDriver::executeProgram(const Module &Program,
295                                                 std::string OutputFile,
296                                                 std::string BitcodeFile,
297                                                 const std::string &SharedObj,
298                                                 AbstractInterpreter *AI) const {
299   if (!AI)
300     AI = Interpreter;
301   assert(AI && "Interpreter should have been created already!");
302   if (BitcodeFile.empty()) {
303     // Emit the program to a bitcode file...
304     auto File =
305         sys::fs::TempFile::create(OutputPrefix + "-test-program-%%%%%%%.bc");
306     if (!File) {
307       errs() << ToolName
308              << ": Error making unique filename: " << toString(File.takeError())
309              << "!\n";
310       exit(1);
311     }
312     DiscardTemp Discard{*File};
313     BitcodeFile = File->TmpName;
314 
315     if (writeProgramToFile(File->FD, Program)) {
316       errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
317              << "'!\n";
318       exit(1);
319     }
320   }
321 
322   if (OutputFile.empty())
323     OutputFile = OutputPrefix + "-execution-output-%%%%%%%";
324 
325   // Check to see if this is a valid output filename...
326   SmallString<128> UniqueFile;
327   std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
328   if (EC) {
329     errs() << ToolName << ": Error making unique filename: " << EC.message()
330            << "\n";
331     exit(1);
332   }
333   OutputFile = UniqueFile.str();
334 
335   // Figure out which shared objects to run, if any.
336   std::vector<std::string> SharedObjs(AdditionalSOs);
337   if (!SharedObj.empty())
338     SharedObjs.push_back(SharedObj);
339 
340   Expected<int> RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile,
341                                             OutputFile, AdditionalLinkerArgs,
342                                             SharedObjs, Timeout, MemoryLimit);
343   if (Error E = RetVal.takeError())
344     return std::move(E);
345 
346   if (*RetVal == -1) {
347     errs() << "<timeout>";
348     static bool FirstTimeout = true;
349     if (FirstTimeout) {
350       outs()
351           << "\n"
352              "*** Program execution timed out!  This mechanism is designed to "
353              "handle\n"
354              "    programs stuck in infinite loops gracefully.  The -timeout "
355              "option\n"
356              "    can be used to change the timeout threshold or disable it "
357              "completely\n"
358              "    (with -timeout=0).  This message is only displayed once.\n";
359       FirstTimeout = false;
360     }
361   }
362 
363   if (AppendProgramExitCode) {
364     std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
365     outFile << "exit " << *RetVal << '\n';
366     outFile.close();
367   }
368 
369   // Return the filename we captured the output to.
370   return OutputFile;
371 }
372 
373 /// Used to create reference output with the "safe" backend, if reference output
374 /// is not provided.
375 Expected<std::string>
376 BugDriver::executeProgramSafely(const Module &Program,
377                                 const std::string &OutputFile) const {
378   return executeProgram(Program, OutputFile, "", "", SafeInterpreter);
379 }
380 
381 Expected<std::string>
382 BugDriver::compileSharedObject(const std::string &BitcodeFile) {
383   assert(Interpreter && "Interpreter should have been created already!");
384   std::string OutputFile;
385 
386   // Using the known-good backend.
387   Expected<CC::FileType> FT =
388       SafeInterpreter->OutputCode(BitcodeFile, OutputFile);
389   if (Error E = FT.takeError())
390     return std::move(E);
391 
392   std::string SharedObjectFile;
393   if (Error E = cc->MakeSharedObject(OutputFile, *FT, SharedObjectFile,
394                                      AdditionalLinkerArgs))
395     return std::move(E);
396 
397   // Remove the intermediate C file
398   sys::fs::remove(OutputFile);
399 
400   return SharedObjectFile;
401 }
402 
403 /// Calls compileProgram and then records the output into ReferenceOutputFile.
404 /// Returns true if reference file created, false otherwise. Note:
405 /// initializeExecutionEnvironment should be called BEFORE this function.
406 Error BugDriver::createReferenceFile(Module &M, const std::string &Filename) {
407   if (Error E = compileProgram(*Program))
408     return E;
409 
410   Expected<std::string> Result = executeProgramSafely(*Program, Filename);
411   if (Error E = Result.takeError()) {
412     if (Interpreter != SafeInterpreter) {
413       E = joinErrors(
414               std::move(E),
415               make_error<StringError>(
416                   "*** There is a bug running the \"safe\" backend.  Either"
417                   " debug it (for example with the -run-jit bugpoint option,"
418                   " if JIT is being used as the \"safe\" backend), or fix the"
419                   " error some other way.\n",
420                   inconvertibleErrorCode()));
421     }
422     return E;
423   }
424   ReferenceOutputFile = *Result;
425   outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
426   return Error::success();
427 }
428 
429 /// This method executes the specified module and diffs the output against the
430 /// file specified by ReferenceOutputFile.  If the output is different, 1 is
431 /// returned.  If there is a problem with the code generator (e.g., llc
432 /// crashes), this will set ErrMsg.
433 Expected<bool> BugDriver::diffProgram(const Module &Program,
434                                       const std::string &BitcodeFile,
435                                       const std::string &SharedObject,
436                                       bool RemoveBitcode) const {
437   // Execute the program, generating an output file...
438   Expected<std::string> Output =
439       executeProgram(Program, "", BitcodeFile, SharedObject, nullptr);
440   if (Error E = Output.takeError())
441     return std::move(E);
442 
443   std::string Error;
444   bool FilesDifferent = false;
445   if (int Diff = DiffFilesWithTolerance(ReferenceOutputFile, *Output,
446                                         AbsTolerance, RelTolerance, &Error)) {
447     if (Diff == 2) {
448       errs() << "While diffing output: " << Error << '\n';
449       exit(1);
450     }
451     FilesDifferent = true;
452   } else {
453     // Remove the generated output if there are no differences.
454     sys::fs::remove(*Output);
455   }
456 
457   // Remove the bitcode file if we are supposed to.
458   if (RemoveBitcode)
459     sys::fs::remove(BitcodeFile);
460   return FilesDifferent;
461 }
462 
463 bool BugDriver::isExecutingJIT() { return InterpreterSel == RunJIT; }
464