FindBugs.cpp revision 198090 
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>
23using 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///
32bool 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}
113