FindBugs.cpp revision 7f27570ae0cb716927f946f4e73a55f60d99b3e2 
1//===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by Patrick Jenkins and is distributed under
6// the University of Illinois Open Source 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 <algorithm>
21#include <ctime>
22#include <iostream>
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  std::string Filename;
34  std::vector<const PassInfo*> TempPass(AllPasses);
35  std::cout << "Starting bug finding procedure...\n\n";
36
37  // Creating a reference output if necessary
38  if (initializeExecutionEnvironment()) return false;
39
40  std::cout << "\n";
41  if (ReferenceOutputFile.empty()) {
42    std::cout << "Generating reference output from raw program: \n";
43    if (!createReferenceFile(Program))
44      return false;
45  }
46
47  srand(time(NULL));
48  std::vector<const PassInfo*>::iterator I = TempPass.begin();
49  std::vector<const PassInfo*>::iterator E = TempPass.end();
50
51  unsigned num = 1;
52  while(1) {
53    //
54    // Step 1: Randomize the order of the optimizer passes.
55    //
56    std::random_shuffle(TempPass.begin(), TempPass.end());
57
58    //
59    // Step 2: Run optimizer passes on the program and check for success.
60    //
61    std::cout << "Running selected passes on program to test for crash: ";
62    for(int i = 0, e = TempPass.size(); i != e; i++) {
63      std::cout << "-" << TempPass[i]->getPassArgument( )<< " ";
64    }
65
66    std::string Filename;
67    if(runPasses(TempPass, Filename, false)) {
68      std::cout << "\n";
69      std::cout << "Optimizer passes caused failure!\n\n";
70      debugOptimizerCrash();
71      return true;
72    } else {
73      std::cout << "Combination " << num << " optimized successfully!\n";
74    }
75
76    //
77    // Step 3: Compile the optimized code.
78    //
79    std::cout << "Running the code generator to test for a crash: ";
80    try {
81      compileProgram(Program);
82      std::cout << '\n';
83    } catch (ToolExecutionError &TEE) {
84      std::cout << "\n*** compileProgram threw an exception: ";
85      std::cout << TEE.what();
86      return debugCodeGeneratorCrash();
87    }
88
89    //
90    // Step 4: Run the program and compare its output to the reference
91    // output (created above).
92    //
93    std::cout << "*** Checking if passes caused miscompliation:\n";
94    try {
95      if (diffProgram(Filename, "", false)) {
96        std::cout << "\n*** diffProgram returned true!\n";
97        debugMiscompilation();
98        return true;
99      } else {
100        std::cout << "\n*** diff'd output matches!\n";
101      }
102    } catch (ToolExecutionError &TEE) {
103      std::cerr << TEE.what();
104      debugCodeGeneratorCrash();
105      return true;
106    }
107
108    sys::Path(Filename).eraseFromDisk();
109
110    std::cout << "\n\n";
111    num++;
112  } //end while
113
114  // Unreachable.
115}
116