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/FileSystem.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <algorithm>
23 #include <ctime>
24 using namespace llvm;
25
26 /// runManyPasses - Take the specified pass list and create different
27 /// combinations of passes to compile the program with. Compile the program with
28 /// each set and mark test to see if it compiled correctly. If the passes
29 /// compiled correctly output nothing and rearrange the passes into a new order.
30 /// If the passes did not compile correctly, output the command required to
31 /// recreate the failure. This returns true if a compiler error is found.
32 ///
runManyPasses(const std::vector<std::string> & AllPasses,std::string & ErrMsg)33 bool BugDriver::runManyPasses(const std::vector<std::string> &AllPasses,
34 std::string &ErrMsg) {
35 setPassesToRun(AllPasses);
36 outs() << "Starting bug finding procedure...\n\n";
37
38 // Creating a reference output if necessary
39 if (initializeExecutionEnvironment()) return false;
40
41 outs() << "\n";
42 if (ReferenceOutputFile.empty()) {
43 outs() << "Generating reference output from raw program: \n";
44 if (!createReferenceFile(Program))
45 return false;
46 }
47
48 srand(time(nullptr));
49
50 unsigned num = 1;
51 while(1) {
52 //
53 // Step 1: Randomize the order of the optimizer passes.
54 //
55 std::random_shuffle(PassesToRun.begin(), PassesToRun.end());
56
57 //
58 // Step 2: Run optimizer passes on the program and check for success.
59 //
60 outs() << "Running selected passes on program to test for crash: ";
61 for(int i = 0, e = PassesToRun.size(); i != e; i++) {
62 outs() << "-" << PassesToRun[i] << " ";
63 }
64
65 std::string Filename;
66 if(runPasses(Program, PassesToRun, Filename, false)) {
67 outs() << "\n";
68 outs() << "Optimizer passes caused failure!\n\n";
69 debugOptimizerCrash();
70 return true;
71 } else {
72 outs() << "Combination " << num << " optimized successfully!\n";
73 }
74
75 //
76 // Step 3: Compile the optimized code.
77 //
78 outs() << "Running the code generator to test for a crash: ";
79 std::string Error;
80 compileProgram(Program, &Error);
81 if (!Error.empty()) {
82 outs() << "\n*** compileProgram threw an exception: ";
83 outs() << Error;
84 return debugCodeGeneratorCrash(ErrMsg);
85 }
86 outs() << '\n';
87
88 //
89 // Step 4: Run the program and compare its output to the reference
90 // output (created above).
91 //
92 outs() << "*** Checking if passes caused miscompliation:\n";
93 bool Diff = diffProgram(Program, Filename, "", false, &Error);
94 if (Error.empty() && Diff) {
95 outs() << "\n*** diffProgram returned true!\n";
96 debugMiscompilation(&Error);
97 if (Error.empty())
98 return true;
99 }
100 if (!Error.empty()) {
101 errs() << Error;
102 debugCodeGeneratorCrash(ErrMsg);
103 return true;
104 }
105 outs() << "\n*** diff'd output matches!\n";
106
107 sys::fs::remove(Filename);
108
109 outs() << "\n\n";
110 num++;
111 } //end while
112
113 // Unreachable.
114 }
115