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      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 ///
    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 = 0;
    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 an 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 == 0;
    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 ///
    266 void BugDriver::compileProgram(Module *M, std::string *Error) const {
    267   // Emit the program to a bitcode file...
    268   sys::Path BitcodeFile (OutputPrefix + "-test-program.bc");
    269   std::string ErrMsg;
    270   if (BitcodeFile.makeUnique(true, &ErrMsg)) {
    271     errs() << ToolName << ": Error making unique filename: " << ErrMsg
    272            << "\n";
    273     exit(1);
    274   }
    275   if (writeProgramToFile(BitcodeFile.str(), M)) {
    276     errs() << ToolName << ": Error emitting bitcode to file '"
    277            << BitcodeFile.str() << "'!\n";
    278     exit(1);
    279   }
    280 
    281   // Remove the temporary bitcode file when we are done.
    282   FileRemover BitcodeFileRemover(BitcodeFile.str(), !SaveTemps);
    283 
    284   // Actually compile the program!
    285   Interpreter->compileProgram(BitcodeFile.str(), Error, Timeout, MemoryLimit);
    286 }
    287 
    288 
    289 /// executeProgram - This method runs "Program", capturing the output of the
    290 /// program to a file, returning the filename of the file.  A recommended
    291 /// filename may be optionally specified.
    292 ///
    293 std::string BugDriver::executeProgram(const Module *Program,
    294                                       std::string OutputFile,
    295                                       std::string BitcodeFile,
    296                                       const std::string &SharedObj,
    297                                       AbstractInterpreter *AI,
    298                                       std::string *Error) const {
    299   if (AI == 0) AI = Interpreter;
    300   assert(AI && "Interpreter should have been created already!");
    301   bool CreatedBitcode = false;
    302   std::string ErrMsg;
    303   if (BitcodeFile.empty()) {
    304     // Emit the program to a bitcode file...
    305     sys::Path uniqueFilename(OutputPrefix + "-test-program.bc");
    306     if (uniqueFilename.makeUnique(true, &ErrMsg)) {
    307       errs() << ToolName << ": Error making unique filename: "
    308              << ErrMsg << "!\n";
    309       exit(1);
    310     }
    311     BitcodeFile = uniqueFilename.str();
    312 
    313     if (writeProgramToFile(BitcodeFile, Program)) {
    314       errs() << ToolName << ": Error emitting bitcode to file '"
    315              << BitcodeFile << "'!\n";
    316       exit(1);
    317     }
    318     CreatedBitcode = true;
    319   }
    320 
    321   // Remove the temporary bitcode file when we are done.
    322   sys::Path BitcodePath(BitcodeFile);
    323   FileRemover BitcodeFileRemover(BitcodePath.str(),
    324     CreatedBitcode && !SaveTemps);
    325 
    326   if (OutputFile.empty()) OutputFile = OutputPrefix + "-execution-output";
    327 
    328   // Check to see if this is a valid output filename...
    329   sys::Path uniqueFile(OutputFile);
    330   if (uniqueFile.makeUnique(true, &ErrMsg)) {
    331     errs() << ToolName << ": Error making unique filename: "
    332            << ErrMsg << "\n";
    333     exit(1);
    334   }
    335   OutputFile = uniqueFile.str();
    336 
    337   // Figure out which shared objects to run, if any.
    338   std::vector<std::string> SharedObjs(AdditionalSOs);
    339   if (!SharedObj.empty())
    340     SharedObjs.push_back(SharedObj);
    341 
    342   int RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile, OutputFile,
    343                                   Error, AdditionalLinkerArgs, SharedObjs,
    344                                   Timeout, MemoryLimit);
    345   if (!Error->empty())
    346     return OutputFile;
    347 
    348   if (RetVal == -1) {
    349     errs() << "<timeout>";
    350     static bool FirstTimeout = true;
    351     if (FirstTimeout) {
    352       outs() << "\n"
    353  "*** Program execution timed out!  This mechanism is designed to handle\n"
    354  "    programs stuck in infinite loops gracefully.  The -timeout option\n"
    355  "    can be used to change the timeout threshold or disable it completely\n"
    356  "    (with -timeout=0).  This message is only displayed once.\n";
    357       FirstTimeout = false;
    358     }
    359   }
    360 
    361   if (AppendProgramExitCode) {
    362     std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
    363     outFile << "exit " << RetVal << '\n';
    364     outFile.close();
    365   }
    366 
    367   // Return the filename we captured the output to.
    368   return OutputFile;
    369 }
    370 
    371 /// executeProgramSafely - Used to create reference output with the "safe"
    372 /// backend, if reference output is not provided.
    373 ///
    374 std::string BugDriver::executeProgramSafely(const Module *Program,
    375                                             std::string OutputFile,
    376                                             std::string *Error) const {
    377   return executeProgram(Program, OutputFile, "", "", SafeInterpreter, Error);
    378 }
    379 
    380 std::string BugDriver::compileSharedObject(const std::string &BitcodeFile,
    381                                            std::string &Error) {
    382   assert(Interpreter && "Interpreter should have been created already!");
    383   sys::Path OutputFile;
    384 
    385   // Using the known-good backend.
    386   GCC::FileType FT = SafeInterpreter->OutputCode(BitcodeFile, OutputFile,
    387                                                  Error);
    388   if (!Error.empty())
    389     return "";
    390 
    391   std::string SharedObjectFile;
    392   bool Failure = gcc->MakeSharedObject(OutputFile.str(), FT, SharedObjectFile,
    393                                        AdditionalLinkerArgs, Error);
    394   if (!Error.empty())
    395     return "";
    396   if (Failure)
    397     exit(1);
    398 
    399   // Remove the intermediate C file
    400   OutputFile.eraseFromDisk();
    401 
    402   return "./" + SharedObjectFile;
    403 }
    404 
    405 /// createReferenceFile - calls compileProgram and then records the output
    406 /// into ReferenceOutputFile. Returns true if reference file created, false
    407 /// otherwise. Note: initializeExecutionEnvironment should be called BEFORE
    408 /// this function.
    409 ///
    410 bool BugDriver::createReferenceFile(Module *M, const std::string &Filename) {
    411   std::string Error;
    412   compileProgram(Program, &Error);
    413   if (!Error.empty())
    414     return false;
    415 
    416   ReferenceOutputFile = executeProgramSafely(Program, Filename, &Error);
    417   if (!Error.empty()) {
    418     errs() << Error;
    419     if (Interpreter != SafeInterpreter) {
    420       errs() << "*** There is a bug running the \"safe\" backend.  Either"
    421              << " debug it (for example with the -run-jit bugpoint option,"
    422              << " if JIT is being used as the \"safe\" backend), or fix the"
    423              << " error some other way.\n";
    424     }
    425     return false;
    426   }
    427   outs() << "\nReference output is: " << ReferenceOutputFile << "\n\n";
    428   return true;
    429 }
    430 
    431 /// diffProgram - This method executes the specified module and diffs the
    432 /// output against the file specified by ReferenceOutputFile.  If the output
    433 /// is different, 1 is returned.  If there is a problem with the code
    434 /// generator (e.g., llc crashes), this will set ErrMsg.
    435 ///
    436 bool BugDriver::diffProgram(const Module *Program,
    437                             const std::string &BitcodeFile,
    438                             const std::string &SharedObject,
    439                             bool RemoveBitcode,
    440                             std::string *ErrMsg) const {
    441   // Execute the program, generating an output file...
    442   sys::Path Output(executeProgram(Program, "", BitcodeFile, SharedObject, 0,
    443                                   ErrMsg));
    444   if (!ErrMsg->empty())
    445     return false;
    446 
    447   std::string Error;
    448   bool FilesDifferent = false;
    449   if (int Diff = DiffFilesWithTolerance(sys::Path(ReferenceOutputFile),
    450                                         sys::Path(Output.str()),
    451                                         AbsTolerance, RelTolerance, &Error)) {
    452     if (Diff == 2) {
    453       errs() << "While diffing output: " << Error << '\n';
    454       exit(1);
    455     }
    456     FilesDifferent = true;
    457   }
    458   else {
    459     // Remove the generated output if there are no differences.
    460     Output.eraseFromDisk();
    461   }
    462 
    463   // Remove the bitcode file if we are supposed to.
    464   if (RemoveBitcode)
    465     sys::Path(BitcodeFile).eraseFromDisk();
    466   return FilesDifferent;
    467 }
    468 
    469 bool BugDriver::isExecutingJIT() {
    470   return InterpreterSel == RunJIT;
    471 }
    472 
    473