static Error ReduceGlobalInitializers(BugDriver &BD,
bool (*TestFn)(const BugDriver &,
Module *)) {
if (BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
// Now try to reduce the number of global variable initializers in the
// module to something small.
Module *M = CloneModule(BD.getProgram()).release();
bool DeletedInit = false;
for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I)
if (I->hasInitializer()) {
DeleteGlobalInitializer(&*I);
I->setLinkage(GlobalValue::ExternalLinkage);
I->setComdat(nullptr);
DeletedInit = true;
}
if (!DeletedInit) {
delete M; // No change made...
} else {
// See if the program still causes a crash...
outs() << "\nChecking to see if we can delete global inits: ";
if (TestFn(BD, M)) { // Still crashes?
BD.setNewProgram(M);
outs() << "\n*** Able to remove all global initializers!\n";
} else { // No longer crashes?
outs() << " - Removing all global inits hides problem!\n";
delete M;
std::vector<GlobalVariable *> GVs;
for (Module::global_iterator I = BD.getProgram()->global_begin(),
E = BD.getProgram()->global_end();
I != E; ++I)
if (I->hasInitializer())
GVs.push_back(&*I);
if (GVs.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of global "
<< "variables in the testcase\n";
unsigned OldSize = GVs.size();
Expected<bool> Result =
ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
if (Error E = Result.takeError())
return E;
if (GVs.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
}
}
}
}
return Error::success();
}
/// DebugACrash - Given a predicate that determines whether a component crashes
/// on a program, try to destructively reduce the program while still keeping
/// the predicate true.
static bool DebugACrash(BugDriver &BD,
bool (*TestFn)(const BugDriver &, Module *),
std::string &Error) {
// See if we can get away with nuking some of the global variable initializers
// in the program...
if (!NoGlobalRM &&
BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
// Now try to reduce the number of global variable initializers in the
// module to something small.
Module *M = CloneModule(BD.getProgram());
bool DeletedInit = false;
for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I)
if (I->hasInitializer()) {
I->setInitializer(nullptr);
I->setLinkage(GlobalValue::ExternalLinkage);
DeletedInit = true;
}
if (!DeletedInit) {
delete M; // No change made...
} else {
// See if the program still causes a crash...
outs() << "\nChecking to see if we can delete global inits: ";
if (TestFn(BD, M)) { // Still crashes?
BD.setNewProgram(M);
outs() << "\n*** Able to remove all global initializers!\n";
} else { // No longer crashes?
outs() << " - Removing all global inits hides problem!\n";
delete M;
std::vector<GlobalVariable*> GVs;
for (Module::global_iterator I = BD.getProgram()->global_begin(),
E = BD.getProgram()->global_end(); I != E; ++I)
if (I->hasInitializer())
GVs.push_back(&*I);
if (GVs.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of global "
<< "variables in the testcase\n";
unsigned OldSize = GVs.size();
ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs, Error);
if (!Error.empty())
return true;
if (GVs.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
}
}
}
}
// Now try to reduce the number of functions in the module to something small.
std::vector<Function*> Functions;
for (Function &F : *BD.getProgram())
if (!F.isDeclaration())
Functions.push_back(&F);
if (Functions.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of functions "
"in the testcase\n";
unsigned OldSize = Functions.size();
ReduceCrashingFunctions(BD, TestFn).reduceList(Functions, Error);
if (Functions.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
}
// Attempt to delete entire basic blocks at a time to speed up
// convergence... this actually works by setting the terminator of the blocks
// to a return instruction then running simplifycfg, which can potentially
// shrinks the code dramatically quickly
//
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock*> Blocks;
for (Function &F : *BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks, Error);
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
}
// 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);
ReduceCrashingInstructions(BD, TestFn).reduceList(Insts, Error);
}
// FIXME: This should use the list reducer to converge faster by deleting
// larger chunks of instructions at a time!
unsigned Simplification = 2;
do {
if (BugpointIsInterrupted) break;
--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) goto ExitLoops;
if (isa<LandingPadInst>(I))
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);
ExitLoops:
// Try to clean up the testcase by running funcresolve and globaldce...
if (!BugpointIsInterrupted) {
outs() << "\n*** Attempting to perform final cleanups: ";
Module *M = CloneModule(BD.getProgram());
M = BD.performFinalCleanups(M, true).release();
// Find out if the pass still crashes on the cleaned up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // Yup, it does, keep the reduced version...
} else {
delete M;
}
}
BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");
return false;
}
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())
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();
}
/// DebugACrash - Given a predicate that determines whether a component crashes
/// on a program, try to destructively reduce the program while still keeping
/// the predicate true.
static Error DebugACrash(BugDriver &BD,
bool (*TestFn)(const BugDriver &, Module *)) {
// See if we can get away with nuking some of the global variable initializers
// in the program...
if (!NoGlobalRM)
if (Error E = ReduceGlobalInitializers(BD, TestFn))
return E;
// Now try to reduce the number of functions in the module to something small.
std::vector<Function *> Functions;
for (Function &F : *BD.getProgram())
if (!F.isDeclaration())
Functions.push_back(&F);
if (Functions.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of functions "
"in the testcase\n";
unsigned OldSize = Functions.size();
Expected<bool> Result =
ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
if (Error E = Result.takeError())
return E;
if (Functions.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
}
// Attempt to change conditional branches into unconditional branches to
// eliminate blocks.
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : *BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result =
ReduceCrashingConditionals(BD, TestFn, true).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
Result = ReduceCrashingConditionals(BD, TestFn, false).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-conditionals");
}
// Attempt to delete entire basic blocks at a time to speed up
// convergence... this actually works by setting the terminator of the blocks
// to a return instruction then running simplifycfg, which can potentially
// shrinks the code dramatically quickly
//
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : *BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result = ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
}
if (!DisableSimplifyCFG & !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : *BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result = ReduceSimplifyCFG(BD, TestFn).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplifycfg");
}
// 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)
if (Error E = ReduceInsts(BD, TestFn))
return E;
// Attempt to strip debug info metadata.
auto stripMetadata = [&](std::function<bool(Module &)> strip) {
std::unique_ptr<Module> M = CloneModule(BD.getProgram());
strip(*M);
if (TestFn(BD, M.get()))
BD.setNewProgram(M.release());
};
if (!NoStripDebugInfo && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to strip the debug info: ";
stripMetadata(StripDebugInfo);
}
if (!NoStripDebugTypeInfo && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to strip the debug type info: ";
stripMetadata(stripNonLineTableDebugInfo);
}
if (!NoNamedMDRM) {
if (!BugpointIsInterrupted) {
// Try to reduce the amount of global metadata (particularly debug info),
// by dropping global named metadata that anchors them
outs() << "\n*** Attempting to remove named metadata: ";
std::vector<std::string> NamedMDNames;
for (auto &NamedMD : BD.getProgram()->named_metadata())
NamedMDNames.push_back(NamedMD.getName().str());
Expected<bool> Result =
ReduceCrashingNamedMD(BD, TestFn).reduceList(NamedMDNames);
if (Error E = Result.takeError())
return E;
}
if (!BugpointIsInterrupted) {
// Now that we quickly dropped all the named metadata that doesn't
// contribute to the crash, bisect the operands of the remaining ones
std::vector<const MDNode *> NamedMDOps;
for (auto &NamedMD : BD.getProgram()->named_metadata())
for (auto op : NamedMD.operands())
NamedMDOps.push_back(op);
Expected<bool> Result =
ReduceCrashingNamedMDOps(BD, TestFn).reduceList(NamedMDOps);
if (Error E = Result.takeError())
return E;
}
BD.EmitProgressBitcode(BD.getProgram(), "reduced-named-md");
}
// Try to clean up the testcase by running funcresolve and globaldce...
if (!BugpointIsInterrupted) {
outs() << "\n*** Attempting to perform final cleanups: ";
Module *M = CloneModule(BD.getProgram()).release();
M = BD.performFinalCleanups(M, true).release();
// Find out if the pass still crashes on the cleaned up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // Yup, it does, keep the reduced version...
} else {
delete M;
}
}
BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");
return Error::success();
}
/// ExtractBlocks - Given a reduced list of functions that still expose the bug,
/// extract as many basic blocks from the region as possible without obscuring
/// the bug.
///
static bool ExtractBlocks(BugDriver &BD,
bool (*TestFn)(BugDriver &, Module *, Module *,
std::string &),
std::vector<Function*> &MiscompiledFunctions,
std::string &Error) {
if (BugpointIsInterrupted) return false;
std::vector<BasicBlock*> Blocks;
for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
for (Function::iterator I = MiscompiledFunctions[i]->begin(),
E = MiscompiledFunctions[i]->end(); I != E; ++I)
Blocks.push_back(I);
// Use the list reducer to identify blocks that can be extracted without
// obscuring the bug. The Blocks list will end up containing blocks that must
// be retained from the original program.
unsigned OldSize = Blocks.size();
// Check to see if all blocks are extractible first.
bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
.TestFuncs(std::vector<BasicBlock*>(), Error);
if (!Error.empty())
return false;
if (Ret) {
Blocks.clear();
} else {
ReduceMiscompiledBlocks(BD, TestFn,
MiscompiledFunctions).reduceList(Blocks, Error);
if (!Error.empty())
return false;
if (Blocks.size() == OldSize)
return false;
}
DenseMap<const Value*, Value*> ValueMap;
Module *ProgClone = CloneModule(BD.getProgram(), ValueMap);
Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
MiscompiledFunctions,
ValueMap);
Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
if (Extracted == 0) {
// Weird, extraction should have worked.
errs() << "Nondeterministic problem extracting blocks??\n";
delete ProgClone;
delete ToExtract;
return false;
}
// Otherwise, block extraction succeeded. Link the two program fragments back
// together.
delete ToExtract;
std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
for (Module::iterator I = Extracted->begin(), E = Extracted->end();
I != E; ++I)
if (!I->isDeclaration())
MisCompFunctions.push_back(std::make_pair(I->getName(),
I->getFunctionType()));
std::string ErrorMsg;
if (Linker::LinkModules(ProgClone, Extracted, &ErrorMsg)) {
errs() << BD.getToolName() << ": Error linking modules together:"
<< ErrorMsg << '\n';
exit(1);
}
delete Extracted;
// Set the new program and delete the old one.
BD.setNewProgram(ProgClone);
// Update the list of miscompiled functions.
MiscompiledFunctions.clear();
for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
assert(NewF && "Function not found??");
assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
"Function has wrong type??");
MiscompiledFunctions.push_back(NewF);
}
return true;
}
/// 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;
DenseMap<const Value*, Value*> ValueMap;
Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap);
Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
MiscompiledFunctions,
ValueMap);
Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
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 = TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize,
false, Error);
if (!Error.empty())
return false;
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;
delete ToOptimizeLoopExtracted;
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);
Module *TNOBackup = CloneModule(ToNotOptimize);
Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
if (!Error.empty())
return false;
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.
delete TOLEBackup;
delete TNOBackup;
return MadeChange;
}
ToOptimizeLoopExtracted = TOLEBackup;
ToNotOptimize = TNOBackup;
outs() << "*** Loop extraction successful!\n";
std::vector<std::pair<std::string, const FunctionType*> > MisCompFunctions;
for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
E = ToOptimizeLoopExtracted->end(); I != E; ++I)
if (!I->isDeclaration())
MisCompFunctions.push_back(std::make_pair(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.
std::string ErrorMsg;
if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, &ErrorMsg)){
errs() << BD.getToolName() << ": Error linking modules together:"
<< ErrorMsg << '\n';
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??");
assert(NewF->getFunctionType() == MisCompFunctions[i].second &&
"found wrong function type?");
MiscompiledFunctions.push_back(NewF);
}
BD.setNewProgram(ToNotOptimize);
MadeChange = true;
}
}
