1 //===- Miscompilation.cpp - Debug program miscompilations -----------------===//
3 // This file implements program miscompilation debugging support.
5 //===----------------------------------------------------------------------===//
8 #include "ListReducer.h"
9 #include "llvm/Module.h"
10 #include "llvm/Pass.h"
11 #include "llvm/Transforms/Utils/Cloning.h"
12 #include "llvm/Transforms/Utils/Linker.h"
13 #include "Support/FileUtilities.h"
15 class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> {
18 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
20 virtual TestResult doTest(std::vector<const PassInfo*> &Prefix,
21 std::vector<const PassInfo*> &Suffix);
24 ReduceMiscompilingPasses::TestResult
25 ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
26 std::vector<const PassInfo*> &Suffix) {
27 // First, run the program with just the Suffix passes. If it is still broken
28 // with JUST the kept passes, discard the prefix passes.
29 std::cout << "Checking to see if '" << getPassesString(Suffix)
30 << "' compile correctly: ";
32 std::string BytecodeResult;
33 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
34 std::cerr << " Error running this sequence of passes"
35 << " on the input program!\n";
36 BD.setPassesToRun(Suffix);
37 BD.EmitProgressBytecode("pass-error", false);
38 exit(BD.debugCrash());
41 // Check to see if the finished program matches the reference output...
42 if (BD.diffProgram(BytecodeResult, "", true /*delete bytecode*/)) {
43 std::cout << "nope.\n";
44 return KeepSuffix; // Miscompilation detected!
46 std::cout << "yup.\n"; // No miscompilation!
48 if (Prefix.empty()) return NoFailure;
50 // Next, see if the program is broken if we run the "prefix" passes first,
51 // then separately run the "kept" passes.
52 std::cout << "Checking to see if '" << getPassesString(Prefix)
53 << "' compile correctly: ";
55 // If it is not broken with the kept passes, it's possible that the prefix
56 // passes must be run before the kept passes to break it. If the program
57 // WORKS after the prefix passes, but then fails if running the prefix AND
58 // kept passes, we can update our bytecode file to include the result of the
59 // prefix passes, then discard the prefix passes.
61 if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
62 std::cerr << " Error running this sequence of passes"
63 << " on the input program!\n";
64 BD.setPassesToRun(Prefix);
65 BD.EmitProgressBytecode("pass-error", false);
66 exit(BD.debugCrash());
69 // If the prefix maintains the predicate by itself, only keep the prefix!
70 if (BD.diffProgram(BytecodeResult)) {
71 std::cout << "nope.\n";
72 removeFile(BytecodeResult);
75 std::cout << "yup.\n"; // No miscompilation!
77 // Ok, so now we know that the prefix passes work, try running the suffix
78 // passes on the result of the prefix passes.
80 Module *PrefixOutput = BD.ParseInputFile(BytecodeResult);
81 if (PrefixOutput == 0) {
82 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
83 << BytecodeResult << "'!\n";
86 removeFile(BytecodeResult); // No longer need the file on disk
88 std::cout << "Checking to see if '" << getPassesString(Suffix)
89 << "' passes compile correctly after the '"
90 << getPassesString(Prefix) << "' passes: ";
92 Module *OriginalInput = BD.Program;
93 BD.Program = PrefixOutput;
94 if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) {
95 std::cerr << " Error running this sequence of passes"
96 << " on the input program!\n";
97 BD.setPassesToRun(Suffix);
98 BD.EmitProgressBytecode("pass-error", false);
99 exit(BD.debugCrash());
103 if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) {
104 std::cout << "nope.\n";
105 delete OriginalInput; // We pruned down the original input...
109 // Otherwise, we must not be running the bad pass anymore.
110 std::cout << "yup.\n"; // No miscompilation!
111 BD.Program = OriginalInput; // Restore original program
112 delete PrefixOutput; // Free experiment
116 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
119 ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {}
121 virtual TestResult doTest(std::vector<Function*> &Prefix,
122 std::vector<Function*> &Suffix) {
123 if (!Suffix.empty() && TestFuncs(Suffix, false))
125 if (!Prefix.empty() && TestFuncs(Prefix, false))
130 bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode);
133 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
135 // Test to see if the function is misoptimized if we ONLY run it on the
136 // functions listed in Funcs.
138 std::cout << "Checking to see if the program is misoptimized when these "
139 << "functions are run\nthrough the passes: ";
140 BD.PrintFunctionList(Funcs);
143 std::cout <<"Outputting reduced bytecode files which expose the problem:\n";
146 // First step: clone the module for the two halves of the program we want.
147 Module *ToOptimize = CloneModule(BD.Program);
149 // Second step: Make sure functions & globals are all external so that linkage
150 // between the two modules will work.
151 for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
152 I->setLinkage(GlobalValue::ExternalLinkage);
153 for (Module::giterator I = ToOptimize->gbegin(), E = ToOptimize->gend();
155 I->setLinkage(GlobalValue::ExternalLinkage);
157 // Third step: make a clone of the externalized program for the non-optimized
159 Module *ToNotOptimize = CloneModule(ToOptimize);
161 // Fourth step: Remove the test functions from the ToNotOptimize module, and
162 // all of the global variables.
163 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
164 Function *TNOF = ToNotOptimize->getFunction(Funcs[i]->getName(),
165 Funcs[i]->getFunctionType());
166 assert(TNOF && "Function doesn't exist in module!");
167 DeleteFunctionBody(TNOF); // Function is now external in this module!
169 for (Module::giterator I = ToNotOptimize->gbegin(), E = ToNotOptimize->gend();
171 I->setInitializer(0); // Delete the initializer to make it external
174 std::cout << " Non-optimized portion: ";
175 std::swap(BD.Program, ToNotOptimize);
176 BD.EmitProgressBytecode("tonotoptimize", true);
177 std::swap(BD.Program, ToNotOptimize);
180 // Fifth step: Remove all functions from the ToOptimize module EXCEPT for the
181 // ones specified in Funcs. We know which ones these are because they are
182 // non-external in ToOptimize, but external in ToNotOptimize.
184 for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I)
185 if (!I->isExternal()) {
186 Function *TNOF = ToNotOptimize->getFunction(I->getName(),
187 I->getFunctionType());
188 assert(TNOF && "Function doesn't exist in ToNotOptimize module??");
189 if (!TNOF->isExternal())
190 DeleteFunctionBody(I);
194 std::cout << " Portion that is input to optimizer: ";
195 std::swap(BD.Program, ToOptimize);
196 BD.EmitProgressBytecode("tooptimize");
197 std::swap(BD.Program, ToOptimize);
200 // Sixth step: Run the optimization passes on ToOptimize, producing a
201 // transformed version of the functions being tested.
202 Module *OldProgram = BD.Program;
203 BD.Program = ToOptimize;
206 std::cout << " Optimizing functions being tested: ";
207 std::string BytecodeResult;
208 if (BD.runPasses(BD.PassesToRun, BytecodeResult, false/*delete*/,
210 std::cerr << " Error running this sequence of passes"
211 << " on the input program!\n";
212 BD.EmitProgressBytecode("pass-error", false);
213 exit(BD.debugCrash());
217 std::cout << "done.\n";
219 delete BD.Program; // Delete the old "ToOptimize" module
220 BD.Program = BD.ParseInputFile(BytecodeResult);
223 std::cout << " 'tooptimize' after being optimized: ";
224 BD.EmitProgressBytecode("optimized", true);
227 if (BD.Program == 0) {
228 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
229 << BytecodeResult << "'!\n";
232 removeFile(BytecodeResult); // No longer need the file on disk
234 // Seventh step: Link the optimized part of the program back to the
235 // unoptimized part of the program.
237 if (LinkModules(BD.Program, ToNotOptimize, &BytecodeResult)) {
238 std::cerr << BD.getToolName() << ": Error linking modules together:"
239 << BytecodeResult << "\n";
242 delete ToNotOptimize; // We are done with this module...
245 std::cout << " Program as tested: ";
246 BD.EmitProgressBytecode("linked", true);
248 BD.Program = OldProgram;
249 return false; // We don't need to actually execute the program here.
252 std::cout << " Checking to see if the merged program executes correctly: ";
254 // Eighth step: Execute the program. If it does not match the expected
255 // output, then 'Funcs' are being misoptimized!
256 bool Broken = BD.diffProgram();
258 delete BD.Program; // Delete the hacked up program
259 BD.Program = OldProgram; // Restore the original
261 std::cout << (Broken ? "nope.\n" : "yup.\n");
266 /// debugMiscompilation - This method is used when the passes selected are not
267 /// crashing, but the generated output is semantically different from the
270 bool BugDriver::debugMiscompilation() {
271 // Make sure something was miscompiled...
272 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) {
273 std::cerr << "*** Optimized program matches reference output! No problem "
274 << "detected...\nbugpoint can't help you with your problem!\n";
278 std::cout << "\n*** Found miscompiling pass"
279 << (PassesToRun.size() == 1 ? "" : "es") << ": "
280 << getPassesString(PassesToRun) << "\n";
281 EmitProgressBytecode("passinput");
283 // Okay, now that we have reduced the list of passes which are causing the
284 // failure, see if we can pin down which functions are being
285 // miscompiled... first build a list of all of the non-external functions in
287 std::vector<Function*> MiscompiledFunctions;
288 for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
289 if (!I->isExternal())
290 MiscompiledFunctions.push_back(I);
292 // Do the reduction...
293 ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions);
295 std::cout << "\n*** The following functions are being miscompiled: ";
296 PrintFunctionList(MiscompiledFunctions);
299 // Output a bunch of bytecode files for the user...
300 ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true);