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 ///
runManyPasses(const std::vector<std::string> & AllPasses,std::string & ErrMsg)32 bool BugDriver::runManyPasses(const std::vector<std::string> &AllPasses,
33 std::string &ErrMsg) {
34 setPassesToRun(AllPasses);
35 outs() << "Starting bug finding procedure...\n\n";
36
37 // Creating a reference output if necessary
38 if (initializeExecutionEnvironment()) return false;
39
40 outs() << "\n";
41 if (ReferenceOutputFile.empty()) {
42 outs() << "Generating reference output from raw program: \n";
43 if (!createReferenceFile(Program))
44 return false;
45 }
46
47 srand(time(NULL));
48
49 unsigned num = 1;
50 while(1) {
51 //
52 // Step 1: Randomize the order of the optimizer passes.
53 //
54 std::random_shuffle(PassesToRun.begin(), PassesToRun.end());
55
56 //
57 // Step 2: Run optimizer passes on the program and check for success.
58 //
59 outs() << "Running selected passes on program to test for crash: ";
60 for(int i = 0, e = PassesToRun.size(); i != e; i++) {
61 outs() << "-" << PassesToRun[i] << " ";
62 }
63
64 std::string Filename;
65 if(runPasses(Program, PassesToRun, Filename, false)) {
66 outs() << "\n";
67 outs() << "Optimizer passes caused failure!\n\n";
68 debugOptimizerCrash();
69 return true;
70 } else {
71 outs() << "Combination " << num << " optimized successfully!\n";
72 }
73
74 //
75 // Step 3: Compile the optimized code.
76 //
77 outs() << "Running the code generator to test for a crash: ";
78 std::string Error;
79 compileProgram(Program, &Error);
80 if (!Error.empty()) {
81 outs() << "\n*** compileProgram threw an exception: ";
82 outs() << Error;
83 return debugCodeGeneratorCrash(ErrMsg);
84 }
85 outs() << '\n';
86
87 //
88 // Step 4: Run the program and compare its output to the reference
89 // output (created above).
90 //
91 outs() << "*** Checking if passes caused miscompliation:\n";
92 bool Diff = diffProgram(Program, Filename, "", false, &Error);
93 if (Error.empty() && Diff) {
94 outs() << "\n*** diffProgram returned true!\n";
95 debugMiscompilation(&Error);
96 if (Error.empty())
97 return true;
98 }
99 if (!Error.empty()) {
100 errs() << Error;
101 debugCodeGeneratorCrash(ErrMsg);
102 return true;
103 }
104 outs() << "\n*** diff'd output matches!\n";
105
106 sys::Path(Filename).eraseFromDisk();
107
108 outs() << "\n\n";
109 num++;
110 } //end while
111
112 // Unreachable.
113 }
114