xref: /freebsd/contrib/llvm-project/llvm/tools/bugpoint/FindBugs.cpp (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1*0b57cec5SDimitry Andric //===-- FindBugs.cpp - Run Many Different Optimizations -------------------===//
2*0b57cec5SDimitry Andric //
3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*0b57cec5SDimitry Andric //
7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
8*0b57cec5SDimitry Andric //
9*0b57cec5SDimitry Andric // This file defines an interface that allows bugpoint to choose different
10*0b57cec5SDimitry Andric // combinations of optimizations to run on the selected input. Bugpoint will
11*0b57cec5SDimitry Andric // run these optimizations and record the success/failure of each. This way
12*0b57cec5SDimitry Andric // we can hopefully spot bugs in the optimizations.
13*0b57cec5SDimitry Andric //
14*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
15*0b57cec5SDimitry Andric 
16*0b57cec5SDimitry Andric #include "BugDriver.h"
17*0b57cec5SDimitry Andric #include "llvm/Support/FileSystem.h"
18*0b57cec5SDimitry Andric #include "llvm/Support/raw_ostream.h"
19*0b57cec5SDimitry Andric #include <random>
20*0b57cec5SDimitry Andric using namespace llvm;
21*0b57cec5SDimitry Andric 
22*0b57cec5SDimitry Andric Error
23*0b57cec5SDimitry Andric BugDriver::runManyPasses(const std::vector<std::string> &AllPasses) {
24*0b57cec5SDimitry Andric   setPassesToRun(AllPasses);
25*0b57cec5SDimitry Andric   outs() << "Starting bug finding procedure...\n\n";
26*0b57cec5SDimitry Andric 
27*0b57cec5SDimitry Andric   // Creating a reference output if necessary
28*0b57cec5SDimitry Andric   if (Error E = initializeExecutionEnvironment())
29*0b57cec5SDimitry Andric     return E;
30*0b57cec5SDimitry Andric 
31*0b57cec5SDimitry Andric   outs() << "\n";
32*0b57cec5SDimitry Andric   if (ReferenceOutputFile.empty()) {
33*0b57cec5SDimitry Andric     outs() << "Generating reference output from raw program: \n";
34*0b57cec5SDimitry Andric     if (Error E = createReferenceFile(*Program))
35*0b57cec5SDimitry Andric       return E;
36*0b57cec5SDimitry Andric   }
37*0b57cec5SDimitry Andric 
38*0b57cec5SDimitry Andric   std::mt19937 randomness(std::random_device{}());
39*0b57cec5SDimitry Andric   unsigned num = 1;
40*0b57cec5SDimitry Andric   while (1) {
41*0b57cec5SDimitry Andric     //
42*0b57cec5SDimitry Andric     // Step 1: Randomize the order of the optimizer passes.
43*0b57cec5SDimitry Andric     //
44*0b57cec5SDimitry Andric     std::shuffle(PassesToRun.begin(), PassesToRun.end(), randomness);
45*0b57cec5SDimitry Andric 
46*0b57cec5SDimitry Andric     //
47*0b57cec5SDimitry Andric     // Step 2: Run optimizer passes on the program and check for success.
48*0b57cec5SDimitry Andric     //
49*0b57cec5SDimitry Andric     outs() << "Running selected passes on program to test for crash: ";
50*0b57cec5SDimitry Andric     for (int i = 0, e = PassesToRun.size(); i != e; i++) {
51*0b57cec5SDimitry Andric       outs() << "-" << PassesToRun[i] << " ";
52*0b57cec5SDimitry Andric     }
53*0b57cec5SDimitry Andric 
54*0b57cec5SDimitry Andric     std::string Filename;
55*0b57cec5SDimitry Andric     if (runPasses(*Program, PassesToRun, Filename, false)) {
56*0b57cec5SDimitry Andric       outs() << "\n";
57*0b57cec5SDimitry Andric       outs() << "Optimizer passes caused failure!\n\n";
58*0b57cec5SDimitry Andric       return debugOptimizerCrash();
59*0b57cec5SDimitry Andric     } else {
60*0b57cec5SDimitry Andric       outs() << "Combination " << num << " optimized successfully!\n";
61*0b57cec5SDimitry Andric     }
62*0b57cec5SDimitry Andric 
63*0b57cec5SDimitry Andric     //
64*0b57cec5SDimitry Andric     // Step 3: Compile the optimized code.
65*0b57cec5SDimitry Andric     //
66*0b57cec5SDimitry Andric     outs() << "Running the code generator to test for a crash: ";
67*0b57cec5SDimitry Andric     if (Error E = compileProgram(*Program)) {
68*0b57cec5SDimitry Andric       outs() << "\n*** compileProgram threw an exception: ";
69*0b57cec5SDimitry Andric       outs() << toString(std::move(E));
70*0b57cec5SDimitry Andric       return debugCodeGeneratorCrash();
71*0b57cec5SDimitry Andric     }
72*0b57cec5SDimitry Andric     outs() << '\n';
73*0b57cec5SDimitry Andric 
74*0b57cec5SDimitry Andric     //
75*0b57cec5SDimitry Andric     // Step 4: Run the program and compare its output to the reference
76*0b57cec5SDimitry Andric     // output (created above).
77*0b57cec5SDimitry Andric     //
78*0b57cec5SDimitry Andric     outs() << "*** Checking if passes caused miscompliation:\n";
79*0b57cec5SDimitry Andric     Expected<bool> Diff = diffProgram(*Program, Filename, "", false);
80*0b57cec5SDimitry Andric     if (Error E = Diff.takeError()) {
81*0b57cec5SDimitry Andric       errs() << toString(std::move(E));
82*0b57cec5SDimitry Andric       return debugCodeGeneratorCrash();
83*0b57cec5SDimitry Andric     }
84*0b57cec5SDimitry Andric     if (*Diff) {
85*0b57cec5SDimitry Andric       outs() << "\n*** diffProgram returned true!\n";
86*0b57cec5SDimitry Andric       Error E = debugMiscompilation();
87*0b57cec5SDimitry Andric       if (!E)
88*0b57cec5SDimitry Andric         return Error::success();
89*0b57cec5SDimitry Andric     }
90*0b57cec5SDimitry Andric     outs() << "\n*** diff'd output matches!\n";
91*0b57cec5SDimitry Andric 
92*0b57cec5SDimitry Andric     sys::fs::remove(Filename);
93*0b57cec5SDimitry Andric 
94*0b57cec5SDimitry Andric     outs() << "\n\n";
95*0b57cec5SDimitry Andric     num++;
96*0b57cec5SDimitry Andric   } // end while
97*0b57cec5SDimitry Andric 
98*0b57cec5SDimitry Andric   // Unreachable.
99*0b57cec5SDimitry Andric }
100