static Error ReduceInsts(BugDriver &BD,
bool (*TestFn)(const BugDriver &, Module *)) {
// Attempt to delete instructions using bisection. This should help out nasty
// cases with large basic blocks where the problem is at one end.
if (!BugpointIsInterrupted) {
std::vector<const Instruction *> Insts;
for (const Function &F : *BD.getProgram())
for (const BasicBlock &BB : F)
for (const Instruction &I : BB)
if (!isa<TerminatorInst>(&I))
Insts.push_back(&I);
Expected<bool> Result =
ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
if (Error E = Result.takeError())
return E;
}
unsigned Simplification = 2;
do {
if (BugpointIsInterrupted)
// TODO: Should we distinguish this with an "interrupted error"?
return Error::success();
--Simplification;
outs() << "\n*** Attempting to reduce testcase by deleting instruc"
<< "tions: Simplification Level #" << Simplification << '\n';
// Now that we have deleted the functions that are unnecessary for the
// program, try to remove instructions that are not necessary to cause the
// crash. To do this, we loop through all of the instructions in the
// remaining functions, deleting them (replacing any values produced with
// nulls), and then running ADCE and SimplifyCFG. If the transformed input
// still triggers failure, keep deleting until we cannot trigger failure
// anymore.
//
unsigned InstructionsToSkipBeforeDeleting = 0;
TryAgain:
// Loop over all of the (non-terminator) instructions remaining in the
// function, attempting to delete them.
unsigned CurInstructionNum = 0;
for (Module::const_iterator FI = BD.getProgram()->begin(),
E = BD.getProgram()->end();
FI != E; ++FI)
if (!FI->isDeclaration())
for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
++BI)
for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
I != E; ++I, ++CurInstructionNum) {
if (InstructionsToSkipBeforeDeleting) {
--InstructionsToSkipBeforeDeleting;
} else {
if (BugpointIsInterrupted)
// TODO: Should this be some kind of interrupted error?
return Error::success();
if (I->isEHPad() || I->getType()->isTokenTy() ||
I->isSwiftError())
continue;
outs() << "Checking instruction: " << *I;
std::unique_ptr<Module> M =
BD.deleteInstructionFromProgram(&*I, Simplification);
// Find out if the pass still crashes on this pass...
if (TestFn(BD, M.get())) {
// Yup, it does, we delete the old module, and continue trying
// to reduce the testcase...
BD.setNewProgram(M.release());
InstructionsToSkipBeforeDeleting = CurInstructionNum;
goto TryAgain; // I wish I had a multi-level break here!
}
}
}
if (InstructionsToSkipBeforeDeleting) {
InstructionsToSkipBeforeDeleting = 0;
goto TryAgain;
}
} while (Simplification);
BD.EmitProgressBitcode(BD.getProgram(), "reduced-instructions");
return Error::success();
}
