/// TestMergedProgram - Given two modules, link them together and run the
/// program, checking to see if the program matches the diff. If the diff
/// matches, return false, otherwise return true. If the DeleteInputs argument
/// is set to true then this function deletes both input modules before it
/// returns.
///
static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2,
bool DeleteInputs, std::string &Error) {
// Link the two portions of the program back to together.
std::string ErrorMsg;
if (!DeleteInputs) {
M1 = CloneModule(M1);
M2 = CloneModule(M2);
}
if (Linker::LinkModules(M1, M2, &ErrorMsg)) {
errs() << BD.getToolName() << ": Error linking modules together:"
<< ErrorMsg << '\n';
exit(1);
}
delete M2; // We are done with this module.
OwningPtr<Module> OldProgram(BD.swapProgramIn(M1));
// Execute the program. If it does not match the expected output, we must
// return true.
bool Broken = BD.diffProgram("", "", false, &Error);
if (!Error.empty()) {
// Delete the linked module & restore the original
delete BD.swapProgramIn(OldProgram.take());
}
return Broken;
}
/// TestOptimizer - This is the predicate function used to check to see if the
/// "Test" portion of the program is misoptimized. If so, return true. In any
/// case, both module arguments are deleted.
///
static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe,
std::string &Error) {
// Run the optimization passes on ToOptimize, producing a transformed version
// of the functions being tested.
outs() << " Optimizing functions being tested: ";
Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
/*AutoDebugCrashes*/true);
outs() << "done.\n";
delete Test;
outs() << " Checking to see if the merged program executes correctly: ";
bool Broken;
Module *New = TestMergedProgram(BD, Optimized, Safe, true, Error, Broken);
if (New) {
outs() << (Broken ? " nope.\n" : " yup.\n");
// Delete the original and set the new program.
delete BD.swapProgramIn(New);
}
return Broken;
}
/// This is the predicate function used to check to see if the "Test" portion of
/// the program is misoptimized. If so, return true. In any case, both module
/// arguments are deleted.
///
static bool TestOptimizer(BugDriver &BD, std::unique_ptr<Module> Test,
std::unique_ptr<Module> Safe, std::string &Error) {
// Run the optimization passes on ToOptimize, producing a transformed version
// of the functions being tested.
outs() << " Optimizing functions being tested: ";
std::unique_ptr<Module> Optimized =
BD.runPassesOn(Test.get(), BD.getPassesToRun(),
/*AutoDebugCrashes*/ true);
outs() << "done.\n";
outs() << " Checking to see if the merged program executes correctly: ";
bool Broken;
std::unique_ptr<Module> New = testMergedProgram(
BD, std::move(Optimized), std::move(Safe), Error, Broken);
if (New) {
outs() << (Broken ? " nope.\n" : " yup.\n");
// Delete the original and set the new program.
delete BD.swapProgramIn(New.release());
}
return Broken;
}
/// ExtractLoops - Given a reduced list of functions that still exposed the bug,
/// check to see if we can extract the loops in the region without obscuring the
/// bug. If so, it reduces the amount of code identified.
///
static bool ExtractLoops(BugDriver &BD,
bool (*TestFn)(BugDriver &, Module *, Module *,
std::string &),
std::vector<Function*> &MiscompiledFunctions,
std::string &Error) {
bool MadeChange = false;
while (1) {
if (BugpointIsInterrupted) return MadeChange;
ValueToValueMapTy VMap;
Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
MiscompiledFunctions,
VMap);
Module *ToOptimizeLoopExtracted = BD.extractLoop(ToOptimize).release();
if (!ToOptimizeLoopExtracted) {
// If the loop extractor crashed or if there were no extractible loops,
// then this chapter of our odyssey is over with.
delete ToNotOptimize;
delete ToOptimize;
return MadeChange;
}
errs() << "Extracted a loop from the breaking portion of the program.\n";
// Bugpoint is intentionally not very trusting of LLVM transformations. In
// particular, we're not going to assume that the loop extractor works, so
// we're going to test the newly loop extracted program to make sure nothing
// has broken. If something broke, then we'll inform the user and stop
// extraction.
AbstractInterpreter *AI = BD.switchToSafeInterpreter();
bool Failure;
Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted,
ToNotOptimize, false, Error, Failure);
if (!New)
return false;
// Delete the original and set the new program.
Module *Old = BD.swapProgramIn(New);
for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
delete Old;
if (Failure) {
BD.switchToInterpreter(AI);
// Merged program doesn't work anymore!
errs() << " *** ERROR: Loop extraction broke the program. :("
<< " Please report a bug!\n";
errs() << " Continuing on with un-loop-extracted version.\n";
BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
ToNotOptimize);
BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
ToOptimize);
BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
ToOptimizeLoopExtracted);
errs() << "Please submit the "
<< OutputPrefix << "-loop-extract-fail-*.bc files.\n";
delete ToOptimize;
delete ToNotOptimize;
return MadeChange;
}
delete ToOptimize;
BD.switchToInterpreter(AI);
outs() << " Testing after loop extraction:\n";
// Clone modules, the tester function will free them.
Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap);
Module *TNOBackup = CloneModule(ToNotOptimize, VMap);
for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
if (!Error.empty())
return false;
ToOptimizeLoopExtracted = TOLEBackup;
ToNotOptimize = TNOBackup;
if (!Failure) {
outs() << "*** Loop extraction masked the problem. Undoing.\n";
// If the program is not still broken, then loop extraction did something
// that masked the error. Stop loop extraction now.
std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
for (Function *F : MiscompiledFunctions) {
MisCompFunctions.emplace_back(F->getName(), F->getFunctionType());
}
if (Linker::linkModules(*ToNotOptimize, *ToOptimizeLoopExtracted,
diagnosticHandler))
exit(1);
MiscompiledFunctions.clear();
for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
assert(NewF && "Function not found??");
MiscompiledFunctions.push_back(NewF);
}
delete ToOptimizeLoopExtracted;
BD.setNewProgram(ToNotOptimize);
return MadeChange;
}
outs() << "*** Loop extraction successful!\n";
std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
E = ToOptimizeLoopExtracted->end(); I != E; ++I)
if (!I->isDeclaration())
MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
// Okay, great! Now we know that we extracted a loop and that loop
// extraction both didn't break the program, and didn't mask the problem.
// Replace the current program with the loop extracted version, and try to
// extract another loop.
if (Linker::linkModules(*ToNotOptimize, *ToOptimizeLoopExtracted,
diagnosticHandler))
exit(1);
delete ToOptimizeLoopExtracted;
// All of the Function*'s in the MiscompiledFunctions list are in the old
// module. Update this list to include all of the functions in the
// optimized and loop extracted module.
MiscompiledFunctions.clear();
for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
assert(NewF && "Function not found??");
MiscompiledFunctions.push_back(NewF);
}
BD.setNewProgram(ToNotOptimize);
MadeChange = true;
}
}
