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      1 //===- OptimizerDriver.cpp - Allow BugPoint to run passes safely ----------===//
      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 defines an interface that allows bugpoint to run various passes
     11 // without the threat of a buggy pass corrupting bugpoint (of course, bugpoint
     12 // may have its own bugs, but that's another story...).  It achieves this by
     13 // forking a copy of itself and having the child process do the optimizations.
     14 // If this client dies, we can always fork a new one.  :)
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #include "BugDriver.h"
     19 #include "llvm/Analysis/Verifier.h"
     20 #include "llvm/Bitcode/ReaderWriter.h"
     21 #include "llvm/IR/DataLayout.h"
     22 #include "llvm/IR/Module.h"
     23 #include "llvm/PassManager.h"
     24 #include "llvm/Support/CommandLine.h"
     25 #include "llvm/Support/Debug.h"
     26 #include "llvm/Support/FileUtilities.h"
     27 #include "llvm/Support/Path.h"
     28 #include "llvm/Support/Program.h"
     29 #include "llvm/Support/SystemUtils.h"
     30 #include "llvm/Support/ToolOutputFile.h"
     31 
     32 #define DONT_GET_PLUGIN_LOADER_OPTION
     33 #include "llvm/Support/PluginLoader.h"
     34 
     35 #include <fstream>
     36 using namespace llvm;
     37 
     38 namespace llvm {
     39   extern cl::opt<std::string> OutputPrefix;
     40 }
     41 
     42 namespace {
     43   // ChildOutput - This option captures the name of the child output file that
     44   // is set up by the parent bugpoint process
     45   cl::opt<std::string> ChildOutput("child-output", cl::ReallyHidden);
     46 }
     47 
     48 /// writeProgramToFile - This writes the current "Program" to the named bitcode
     49 /// file.  If an error occurs, true is returned.
     50 ///
     51 bool BugDriver::writeProgramToFile(const std::string &Filename,
     52                                    const Module *M) const {
     53   std::string ErrInfo;
     54   tool_output_file Out(Filename.c_str(), ErrInfo,
     55                        raw_fd_ostream::F_Binary);
     56   if (ErrInfo.empty()) {
     57     WriteBitcodeToFile(M, Out.os());
     58     Out.os().close();
     59     if (!Out.os().has_error()) {
     60       Out.keep();
     61       return false;
     62     }
     63   }
     64   Out.os().clear_error();
     65   return true;
     66 }
     67 
     68 
     69 /// EmitProgressBitcode - This function is used to output the current Program
     70 /// to a file named "bugpoint-ID.bc".
     71 ///
     72 void BugDriver::EmitProgressBitcode(const Module *M,
     73                                     const std::string &ID,
     74                                     bool NoFlyer)  const {
     75   // Output the input to the current pass to a bitcode file, emit a message
     76   // telling the user how to reproduce it: opt -foo blah.bc
     77   //
     78   std::string Filename = OutputPrefix + "-" + ID + ".bc";
     79   if (writeProgramToFile(Filename, M)) {
     80     errs() <<  "Error opening file '" << Filename << "' for writing!\n";
     81     return;
     82   }
     83 
     84   outs() << "Emitted bitcode to '" << Filename << "'\n";
     85   if (NoFlyer || PassesToRun.empty()) return;
     86   outs() << "\n*** You can reproduce the problem with: ";
     87   if (UseValgrind) outs() << "valgrind ";
     88   outs() << "opt " << Filename;
     89   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
     90     outs() << " -load " << PluginLoader::getPlugin(i);
     91   }
     92   outs() << " " << getPassesString(PassesToRun) << "\n";
     93 }
     94 
     95 cl::opt<bool> SilencePasses("silence-passes",
     96         cl::desc("Suppress output of running passes (both stdout and stderr)"));
     97 
     98 static cl::list<std::string> OptArgs("opt-args", cl::Positional,
     99                                      cl::desc("<opt arguments>..."),
    100                                      cl::ZeroOrMore, cl::PositionalEatsArgs);
    101 
    102 /// runPasses - Run the specified passes on Program, outputting a bitcode file
    103 /// and writing the filename into OutputFile if successful.  If the
    104 /// optimizations fail for some reason (optimizer crashes), return true,
    105 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
    106 /// deleted on success, and the filename string is undefined.  This prints to
    107 /// outs() a single line message indicating whether compilation was successful
    108 /// or failed.
    109 ///
    110 bool BugDriver::runPasses(Module *Program,
    111                           const std::vector<std::string> &Passes,
    112                           std::string &OutputFilename, bool DeleteOutput,
    113                           bool Quiet, unsigned NumExtraArgs,
    114                           const char * const *ExtraArgs) const {
    115   // setup the output file name
    116   outs().flush();
    117   sys::Path uniqueFilename(OutputPrefix + "-output.bc");
    118   std::string ErrMsg;
    119   if (uniqueFilename.makeUnique(true, &ErrMsg)) {
    120     errs() << getToolName() << ": Error making unique filename: "
    121            << ErrMsg << "\n";
    122     return(1);
    123   }
    124   OutputFilename = uniqueFilename.str();
    125 
    126   // set up the input file name
    127   sys::Path inputFilename(OutputPrefix + "-input.bc");
    128   if (inputFilename.makeUnique(true, &ErrMsg)) {
    129     errs() << getToolName() << ": Error making unique filename: "
    130            << ErrMsg << "\n";
    131     return(1);
    132   }
    133 
    134   std::string ErrInfo;
    135   tool_output_file InFile(inputFilename.c_str(), ErrInfo,
    136                           raw_fd_ostream::F_Binary);
    137 
    138 
    139   if (!ErrInfo.empty()) {
    140     errs() << "Error opening bitcode file: " << inputFilename.str() << "\n";
    141     return 1;
    142   }
    143   WriteBitcodeToFile(Program, InFile.os());
    144   InFile.os().close();
    145   if (InFile.os().has_error()) {
    146     errs() << "Error writing bitcode file: " << inputFilename.str() << "\n";
    147     InFile.os().clear_error();
    148     return 1;
    149   }
    150 
    151   sys::Path tool = sys::Program::FindProgramByName("opt");
    152   if (tool.empty()) {
    153     errs() << "Cannot find `opt' in PATH!\n";
    154     return 1;
    155   }
    156 
    157   // Ok, everything that could go wrong before running opt is done.
    158   InFile.keep();
    159 
    160   // setup the child process' arguments
    161   SmallVector<const char*, 8> Args;
    162   std::string Opt = tool.str();
    163   if (UseValgrind) {
    164     Args.push_back("valgrind");
    165     Args.push_back("--error-exitcode=1");
    166     Args.push_back("-q");
    167     Args.push_back(tool.c_str());
    168   } else
    169     Args.push_back(Opt.c_str());
    170 
    171   Args.push_back("-o");
    172   Args.push_back(OutputFilename.c_str());
    173   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
    174     Args.push_back(OptArgs[i].c_str());
    175   std::vector<std::string> pass_args;
    176   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
    177     pass_args.push_back( std::string("-load"));
    178     pass_args.push_back( PluginLoader::getPlugin(i));
    179   }
    180   for (std::vector<std::string>::const_iterator I = Passes.begin(),
    181        E = Passes.end(); I != E; ++I )
    182     pass_args.push_back( std::string("-") + (*I) );
    183   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
    184        E = pass_args.end(); I != E; ++I )
    185     Args.push_back(I->c_str());
    186   Args.push_back(inputFilename.c_str());
    187   for (unsigned i = 0; i < NumExtraArgs; ++i)
    188     Args.push_back(*ExtraArgs);
    189   Args.push_back(0);
    190 
    191   DEBUG(errs() << "\nAbout to run:\t";
    192         for (unsigned i = 0, e = Args.size()-1; i != e; ++i)
    193           errs() << " " << Args[i];
    194         errs() << "\n";
    195         );
    196 
    197   sys::Path prog;
    198   if (UseValgrind)
    199     prog = sys::Program::FindProgramByName("valgrind");
    200   else
    201     prog = tool;
    202 
    203   // Redirect stdout and stderr to nowhere if SilencePasses is given
    204   sys::Path Nowhere;
    205   const sys::Path *Redirects[3] = {0, &Nowhere, &Nowhere};
    206 
    207   int result = sys::Program::ExecuteAndWait(prog, Args.data(), 0,
    208                                             (SilencePasses ? Redirects : 0),
    209                                             Timeout, MemoryLimit, &ErrMsg);
    210 
    211   // If we are supposed to delete the bitcode file or if the passes crashed,
    212   // remove it now.  This may fail if the file was never created, but that's ok.
    213   if (DeleteOutput || result != 0)
    214     sys::Path(OutputFilename).eraseFromDisk();
    215 
    216   // Remove the temporary input file as well
    217   inputFilename.eraseFromDisk();
    218 
    219   if (!Quiet) {
    220     if (result == 0)
    221       outs() << "Success!\n";
    222     else if (result > 0)
    223       outs() << "Exited with error code '" << result << "'\n";
    224     else if (result < 0) {
    225       if (result == -1)
    226         outs() << "Execute failed: " << ErrMsg << "\n";
    227       else
    228         outs() << "Crashed: " << ErrMsg << "\n";
    229     }
    230     if (result & 0x01000000)
    231       outs() << "Dumped core\n";
    232   }
    233 
    234   // Was the child successful?
    235   return result != 0;
    236 }
    237 
    238 
    239 /// runPassesOn - Carefully run the specified set of pass on the specified
    240 /// module, returning the transformed module on success, or a null pointer on
    241 /// failure.
    242 Module *BugDriver::runPassesOn(Module *M,
    243                                const std::vector<std::string> &Passes,
    244                                bool AutoDebugCrashes, unsigned NumExtraArgs,
    245                                const char * const *ExtraArgs) {
    246   std::string BitcodeResult;
    247   if (runPasses(M, Passes, BitcodeResult, false/*delete*/, true/*quiet*/,
    248                 NumExtraArgs, ExtraArgs)) {
    249     if (AutoDebugCrashes) {
    250       errs() << " Error running this sequence of passes"
    251              << " on the input program!\n";
    252       delete swapProgramIn(M);
    253       EmitProgressBitcode(M, "pass-error",  false);
    254       exit(debugOptimizerCrash());
    255     }
    256     return 0;
    257   }
    258 
    259   Module *Ret = ParseInputFile(BitcodeResult, Context);
    260   if (Ret == 0) {
    261     errs() << getToolName() << ": Error reading bitcode file '"
    262            << BitcodeResult << "'!\n";
    263     exit(1);
    264   }
    265   sys::Path(BitcodeResult).eraseFromDisk();  // No longer need the file on disk
    266   return Ret;
    267 }
    268