tools/bugpoint/FindBugs.cpp

   1 //===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//
   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 choose different
  11 // combinations of optimizations to run on the selected input. Bugpoint will
  12 // run these optimizations and record the success/failure of each. This way
  13 // we can hopefully spot bugs in the optimizations.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "BugDriver.h"
  18 #include "ToolRunner.h"
  19 #include "llvm/Pass.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include <algorithm>
  22 #include <ctime>
  23 using namespace llvm;
  24
  25 /// runManyPasses - Take the specified pass list and create different
  26 /// combinations of passes to compile the program with. Compile the program with
  27 /// each set and mark test to see if it compiled correctly. If the passes
  28 /// compiled correctly output nothing and rearrange the passes into a new order.
  29 /// If the passes did not compile correctly, output the command required to
  30 /// recreate the failure. This returns true if a compiler error is found.
  31 ///
  32 bool BugDriver::runManyPasses(const std::vector<const PassInfo*> &AllPasses) {
  33   setPassesToRun(AllPasses);
  34   outs() << "Starting bug finding procedure...\n\n";
  35
  36   // Creating a reference output if necessary
  37   if (initializeExecutionEnvironment()) return false;
  38
  39   outs() << "\n";
  40   if (ReferenceOutputFile.empty()) {
  41     outs() << "Generating reference output from raw program: \n";
  42     if (!createReferenceFile(Program))
  43       return false;
  44   }
  45
  46   srand(time(NULL));
  47
  48   unsigned num = 1;
  49   while(1) {
  50     //
  51     // Step 1: Randomize the order of the optimizer passes.
  52     //
  53     std::random_shuffle(PassesToRun.begin(), PassesToRun.end());
  54
  55     //
  56     // Step 2: Run optimizer passes on the program and check for success.
  57     //
  58     outs() << "Running selected passes on program to test for crash: ";
  59     for(int i = 0, e = PassesToRun.size(); i != e; i++) {
  60       outs() << "-" << PassesToRun[i]->getPassArgument( )<< " ";
  61     }
  62
  63     std::string Filename;
  64     if(runPasses(PassesToRun, Filename, false)) {
  65       outs() << "\n";
  66       outs() << "Optimizer passes caused failure!\n\n";
  67       debugOptimizerCrash();
  68       return true;
  69     } else {
  70       outs() << "Combination " << num << " optimized successfully!\n";
  71     }
  72
  73     //
  74     // Step 3: Compile the optimized code.
  75     //
  76     outs() << "Running the code generator to test for a crash: ";
  77     try {
  78       compileProgram(Program);
  79       outs() << '\n';
  80     } catch (ToolExecutionError &TEE) {
  81       outs() << "\n*** compileProgram threw an exception: ";
  82       outs() << TEE.what();
  83       return debugCodeGeneratorCrash();
  84     }
  85
  86     //
  87     // Step 4: Run the program and compare its output to the reference
  88     // output (created above).
  89     //
  90     outs() << "*** Checking if passes caused miscompliation:\n";
  91     try {
  92       if (diffProgram(Filename, "", false)) {
  93         outs() << "\n*** diffProgram returned true!\n";
  94         debugMiscompilation();
  95         return true;
  96       } else {
  97         outs() << "\n*** diff'd output matches!\n";
  98       }
  99     } catch (ToolExecutionError &TEE) {
 100       errs() << TEE.what();
 101       debugCodeGeneratorCrash();
 102       return true;
 103     }
 104
 105     sys::Path(Filename).eraseFromDisk();
 106
 107     outs() << "\n\n";
 108     num++;
 109   } //end while
 110
 111   // Unreachable.
 112 }