/// 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();
}
/// 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;
}
/// CleanupAndPrepareModules - Get the specified modules ready for code
/// generator testing.
///
static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
Module *Safe) {
// Clean up the modules, removing extra cruft that we don't need anymore...
Test = BD.performFinalCleanups(Test);
// If we are executing the JIT, we have several nasty issues to take care of.
if (!BD.isExecutingJIT()) return;
// First, if the main function is in the Safe module, we must add a stub to
// the Test module to call into it. Thus, we create a new function `main'
// which just calls the old one.
if (Function *oldMain = Safe->getFunction("main"))
if (!oldMain->isDeclaration()) {
// Rename it
oldMain->setName("llvm_bugpoint_old_main");
// Create a NEW `main' function with same type in the test module.
Function *newMain = Function::Create(oldMain->getFunctionType(),
GlobalValue::ExternalLinkage,
"main", Test);
// Create an `oldmain' prototype in the test module, which will
// corresponds to the real main function in the same module.
Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
GlobalValue::ExternalLinkage,
oldMain->getName(), Test);
// Set up and remember the argument list for the main function.
std::vector<Value*> args;
for (Function::arg_iterator
I = newMain->arg_begin(), E = newMain->arg_end(),
OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
I->setName(OI->getName()); // Copy argument names from oldMain
args.push_back(I);
}
// Call the old main function and return its result
BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
CallInst *call = CallInst::Create(oldMainProto, args.begin(), args.end(),
"", BB);
// If the type of old function wasn't void, return value of call
ReturnInst::Create(Safe->getContext(), call, BB);
}
// The second nasty issue we must deal with in the JIT is that the Safe
// module cannot directly reference any functions defined in the test
// module. Instead, we use a JIT API call to dynamically resolve the
// symbol.
// Add the resolver to the Safe module.
// Prototype: void *getPointerToNamedFunction(const char* Name)
Constant *resolverFunc =
Safe->getOrInsertFunction("getPointerToNamedFunction",
Type::getInt8PtrTy(Safe->getContext()),
Type::getInt8PtrTy(Safe->getContext()),
(Type *)0);
// Use the function we just added to get addresses of functions we need.
for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
!F->isIntrinsic() /* ignore intrinsics */) {
Function *TestFn = Test->getFunction(F->getName());
// Don't forward functions which are external in the test module too.
if (TestFn && !TestFn->isDeclaration()) {
// 1. Add a string constant with its name to the global file
Constant *InitArray = ConstantArray::get(F->getContext(), F->getName());
GlobalVariable *funcName =
new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
GlobalValue::InternalLinkage, InitArray,
F->getName() + "_name");
// 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
// sbyte* so it matches the signature of the resolver function.
// GetElementPtr *funcName, ulong 0, ulong 0
std::vector<Constant*> GEPargs(2,
Constant::getNullValue(Type::getInt32Ty(F->getContext())));
Value *GEP =
ConstantExpr::getGetElementPtr(funcName, &GEPargs[0], 2);
std::vector<Value*> ResolverArgs;
ResolverArgs.push_back(GEP);
// Rewrite uses of F in global initializers, etc. to uses of a wrapper
// function that dynamically resolves the calls to F via our JIT API
if (!F->use_empty()) {
// Create a new global to hold the cached function pointer.
Constant *NullPtr = ConstantPointerNull::get(F->getType());
GlobalVariable *Cache =
new GlobalVariable(*F->getParent(), F->getType(),
false, GlobalValue::InternalLinkage,
NullPtr,F->getName()+".fpcache");
// Construct a new stub function that will re-route calls to F
const FunctionType *FuncTy = F->getFunctionType();
Function *FuncWrapper = Function::Create(FuncTy,
GlobalValue::InternalLinkage,
F->getName() + "_wrapper",
F->getParent());
BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
"entry", FuncWrapper);
BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
"usecache", FuncWrapper);
BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
"lookupfp", FuncWrapper);
// Check to see if we already looked up the value.
Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
NullPtr, "isNull");
BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
// Resolve the call to function F via the JIT API:
//
// call resolver(GetElementPtr...)
CallInst *Resolver =
CallInst::Create(resolverFunc, ResolverArgs.begin(),
ResolverArgs.end(), "resolver", LookupBB);
// Cast the result from the resolver to correctly-typed function.
CastInst *CastedResolver =
new BitCastInst(Resolver,
PointerType::getUnqual(F->getFunctionType()),
"resolverCast", LookupBB);
// Save the value in our cache.
new StoreInst(CastedResolver, Cache, LookupBB);
BranchInst::Create(DoCallBB, LookupBB);
PHINode *FuncPtr = PHINode::Create(NullPtr->getType(),
"fp", DoCallBB);
FuncPtr->addIncoming(CastedResolver, LookupBB);
FuncPtr->addIncoming(CachedVal, EntryBB);
// Save the argument list.
std::vector<Value*> Args;
for (Function::arg_iterator i = FuncWrapper->arg_begin(),
e = FuncWrapper->arg_end(); i != e; ++i)
Args.push_back(i);
// Pass on the arguments to the real function, return its result
if (F->getReturnType()->isVoidTy()) {
CallInst::Create(FuncPtr, Args.begin(), Args.end(), "", DoCallBB);
ReturnInst::Create(F->getContext(), DoCallBB);
} else {
CallInst *Call = CallInst::Create(FuncPtr, Args.begin(), Args.end(),
"retval", DoCallBB);
ReturnInst::Create(F->getContext(),Call, DoCallBB);
}
// Use the wrapper function instead of the old function
F->replaceAllUsesWith(FuncWrapper);
}
}
}
}
if (verifyModule(*Test) || verifyModule(*Safe)) {
errs() << "Bugpoint has a bug, which corrupted a module!!\n";
abort();
}
}
