/// Evaluate a call to function F, returning true if successful, false if we
/// can't evaluate it. ActualArgs contains the formal arguments for the
/// function.
bool Evaluator::EvaluateFunction(Function *F, Constant *&RetVal,
const SmallVectorImpl<Constant*> &ActualArgs) {
// Check to see if this function is already executing (recursion). If so,
// bail out. TODO: we might want to accept limited recursion.
if (is_contained(CallStack, F))
return false;
CallStack.push_back(F);
// Initialize arguments to the incoming values specified.
unsigned ArgNo = 0;
for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); AI != E;
++AI, ++ArgNo)
setVal(&*AI, ActualArgs[ArgNo]);
// ExecutedBlocks - We only handle non-looping, non-recursive code. As such,
// we can only evaluate any one basic block at most once. This set keeps
// track of what we have executed so we can detect recursive cases etc.
SmallPtrSet<BasicBlock*, 32> ExecutedBlocks;
// CurBB - The current basic block we're evaluating.
BasicBlock *CurBB = &F->front();
BasicBlock::iterator CurInst = CurBB->begin();
while (1) {
BasicBlock *NextBB = nullptr; // Initialized to avoid compiler warnings.
DEBUG(dbgs() << "Trying to evaluate BB: " << *CurBB << "\n");
if (!EvaluateBlock(CurInst, NextBB))
return false;
if (!NextBB) {
// Successfully running until there's no next block means that we found
// the return. Fill it the return value and pop the call stack.
ReturnInst *RI = cast<ReturnInst>(CurBB->getTerminator());
if (RI->getNumOperands())
RetVal = getVal(RI->getOperand(0));
CallStack.pop_back();
return true;
}
// Okay, we succeeded in evaluating this control flow. See if we have
// executed the new block before. If so, we have a looping function,
// which we cannot evaluate in reasonable time.
if (!ExecutedBlocks.insert(NextBB).second)
return false; // looped!
// Okay, we have never been in this block before. Check to see if there
// are any PHI nodes. If so, evaluate them with information about where
// we came from.
PHINode *PN = nullptr;
for (CurInst = NextBB->begin();
(PN = dyn_cast<PHINode>(CurInst)); ++CurInst)
setVal(PN, getVal(PN->getIncomingValueForBlock(CurBB)));
// Advance to the next block.
CurBB = NextBB;
}
}
void Interpreter::visitReturnInst(ReturnInst &I) {
ExecutionContext &SF = ECStack.back();
const Type *RetTy = Type::VoidTy;
GenericValue Result;
// Save away the return value... (if we are not 'ret void')
if (I.getNumOperands()) {
RetTy = I.getReturnValue()->getType();
Result = getOperandValue(I.getReturnValue(), SF);
}
popStackAndReturnValueToCaller(RetTy, Result);
}
/// mergeEmptyReturnBlocks - If we have more than one empty (other than phi
/// node) return blocks, merge them together to promote recursive block merging.
static bool mergeEmptyReturnBlocks(Function &F) {
bool Changed = false;
BasicBlock *RetBlock = 0;
// Scan all the blocks in the function, looking for empty return blocks.
for (Function::iterator BBI = F.begin(), E = F.end(); BBI != E; ) {
BasicBlock &BB = *BBI++;
// Only look at return blocks.
ReturnInst *Ret = dyn_cast<ReturnInst>(BB.getTerminator());
if (Ret == 0) continue;
// Only look at the block if it is empty or the only other thing in it is a
// single PHI node that is the operand to the return.
if (Ret != &BB.front()) {
// Check for something else in the block.
BasicBlock::iterator I = Ret;
--I;
// Skip over debug info.
while (isa<DbgInfoIntrinsic>(I) && I != BB.begin())
--I;
if (!isa<DbgInfoIntrinsic>(I) &&
(!isa<PHINode>(I) || I != BB.begin() ||
Ret->getNumOperands() == 0 ||
Ret->getOperand(0) != I))
continue;
}
// If this is the first returning block, remember it and keep going.
if (RetBlock == 0) {
RetBlock = &BB;
continue;
}
// Otherwise, we found a duplicate return block. Merge the two.
Changed = true;
// Case when there is no input to the return or when the returned values
// agree is trivial. Note that they can't agree if there are phis in the
// blocks.
if (Ret->getNumOperands() == 0 ||
Ret->getOperand(0) ==
cast<ReturnInst>(RetBlock->getTerminator())->getOperand(0)) {
BB.replaceAllUsesWith(RetBlock);
BB.eraseFromParent();
continue;
}
// If the canonical return block has no PHI node, create one now.
PHINode *RetBlockPHI = dyn_cast<PHINode>(RetBlock->begin());
if (RetBlockPHI == 0) {
Value *InVal = cast<ReturnInst>(RetBlock->getTerminator())->getOperand(0);
pred_iterator PB = pred_begin(RetBlock), PE = pred_end(RetBlock);
RetBlockPHI = PHINode::Create(Ret->getOperand(0)->getType(),
std::distance(PB, PE), "merge",
&RetBlock->front());
for (pred_iterator PI = PB; PI != PE; ++PI)
RetBlockPHI->addIncoming(InVal, *PI);
RetBlock->getTerminator()->setOperand(0, RetBlockPHI);
}
// Turn BB into a block that just unconditionally branches to the return
// block. This handles the case when the two return blocks have a common
// predecessor but that return different things.
RetBlockPHI->addIncoming(Ret->getOperand(0), &BB);
BB.getTerminator()->eraseFromParent();
BranchInst::Create(RetBlock, &BB);
}
return Changed;
}
void GraphBuilder::visitReturnInst(ReturnInst &RI) {
if (RI.getNumOperands() && isa<PointerType>(RI.getOperand(0)->getType()))
G.getOrCreateReturnNodeFor(*FB).mergeWith(getValueDest(RI.getOperand(0)));
}
void AAAnalyzer::handle_inst(Instruction *inst, FunctionWrapper * parent_func) {
//outs()<<*inst<<"\n"; outs().flush();
switch (inst->getOpcode()) {
// common/bitwise binary operations
// Terminator instructions
case Instruction::Ret:
{
ReturnInst* retInst = ((ReturnInst*) inst);
if (retInst->getNumOperands() > 0 && !retInst->getOperandUse(0)->getType()->isVoidTy()) {
parent_func->addRet(retInst->getOperandUse(0));
}
}
break;
case Instruction::Resume:
{
Value* resume = ((ResumeInst*) inst)->getOperand(0);
parent_func->addResume(resume);
}
break;
case Instruction::Switch:
case Instruction::Br:
case Instruction::IndirectBr:
case Instruction::Unreachable:
break;
// vector operations
case Instruction::ExtractElement:
{
}
break;
case Instruction::InsertElement:
{
}
break;
case Instruction::ShuffleVector:
{
}
break;
// aggregate operations
case Instruction::ExtractValue:
{
Value * agg = ((ExtractValueInst*) inst)->getAggregateOperand();
DyckVertex* aggV = wrapValue(agg);
Type* aggTy = agg->getType();
ArrayRef<unsigned> indices = ((ExtractValueInst*) inst)->getIndices();
DyckVertex* currentStruct = aggV;
for (unsigned int i = 0; i < indices.size(); i++) {
if (isa<CompositeType>(aggTy) && aggTy->isSized()) {
if (!aggTy->isStructTy()) {
aggTy = ((CompositeType*) aggTy)->getTypeAtIndex(indices[i]);
#ifndef ARRAY_SIMPLIFIED
current = addPtrOffset(current, (int) indices[i] * dl.getTypeAllocSize(aggTy), dgraph);
#endif
if (i == indices.size() - 1) {
this->makeAlias(currentStruct, wrapValue(inst));
}
} else {
aggTy = ((CompositeType*) aggTy)->getTypeAtIndex(indices[i]);
if (i != indices.size() - 1) {
currentStruct = this->addField(currentStruct, -2 - (int) indices[i], NULL);
} else {
currentStruct = this->addField(currentStruct, -2 - (int) indices[i], wrapValue(inst));
}
}
} else {
break;
}
}
}
break;
case Instruction::InsertValue:
{
DyckVertex* resultV = wrapValue(inst);
Value * agg = ((InsertValueInst*) inst)->getAggregateOperand();
if (!isa<UndefValue>(agg)) {
makeAlias(resultV, wrapValue(agg));
}
Value * val = ((InsertValueInst*) inst)->getInsertedValueOperand();
DyckVertex* insertedVal = wrapValue(val);
Type *aggTy = inst->getType();
ArrayRef<unsigned> indices = ((InsertValueInst*) inst)->getIndices();
DyckVertex* currentStruct = resultV;
for (unsigned int i = 0; i < indices.size(); i++) {
if (isa<CompositeType>(aggTy) && aggTy->isSized()) {
if (!aggTy->isStructTy()) {
aggTy = ((CompositeType*) aggTy)->getTypeAtIndex(indices[i]);
#ifndef ARRAY_SIMPLIFIED
current = addPtrOffset(current, (int) indices[i] * dl.getTypeAllocSize(aggTy), dgraph);
#endif
if (i == indices.size() - 1) {
this->makeAlias(currentStruct, insertedVal);
}
} else {
aggTy = ((CompositeType*) aggTy)->getTypeAtIndex(indices[i]);
if (i != indices.size() - 1) {
currentStruct = this->addField(currentStruct, -2 - (int) indices[i], NULL);
} else {
currentStruct = this->addField(currentStruct, -2 - (int) indices[i], insertedVal);
}
}
} else {
break;
}
}
}
break;
// memory accessing and addressing operations
case Instruction::Alloca:
{
}
break;
case Instruction::Fence:
{
}
break;
case Instruction::AtomicCmpXchg:
{
Value * retXchg = inst;
Value * ptrXchg = inst->getOperand(0);
Value * newXchg = inst->getOperand(2);
addPtrTo(wrapValue(ptrXchg), wrapValue(retXchg));
addPtrTo(wrapValue(ptrXchg), wrapValue(newXchg));
}
break;
case Instruction::AtomicRMW:
{
Value * retRmw = inst;
Value * ptrRmw = ((AtomicRMWInst*) inst)->getPointerOperand();
addPtrTo(wrapValue(ptrRmw), wrapValue(retRmw));
switch (((AtomicRMWInst*) inst)->getOperation()) {
case AtomicRMWInst::Max:
case AtomicRMWInst::Min:
case AtomicRMWInst::UMax:
case AtomicRMWInst::UMin:
case AtomicRMWInst::Xchg:
{
Value * newRmw = ((AtomicRMWInst*) inst)->getValOperand();
addPtrTo(wrapValue(ptrRmw), wrapValue(newRmw));
}
break;
default:
//others are binary ops like add/sub/...
///@TODO
break;
}
}
break;
case Instruction::Load:
{
Value *lval = inst;
Value *ladd = inst->getOperand(0);
addPtrTo(wrapValue(ladd), wrapValue(lval));
}
break;
case Instruction::Store:
{
Value * sval = inst->getOperand(0);
Value * sadd = inst->getOperand(1);
addPtrTo(wrapValue(sadd), wrapValue(sval));
}
break;
case Instruction::GetElementPtr:
{
makeAlias(wrapValue(inst), handle_gep((GEPOperator*) inst));
}
break;
// conversion operations
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::BitCast:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
{
Value * itpv = inst->getOperand(0);
makeAlias(wrapValue(inst), wrapValue(itpv));
}
break;
// other operations
case Instruction::Invoke: // invoke is a terminal operation
{
InvokeInst * invoke = (InvokeInst*) inst;
LandingPadInst* lpd = invoke->getLandingPadInst();
parent_func->addLandingPad(invoke, lpd);
Value * cv = invoke->getCalledValue();
vector<Value*> args;
for (unsigned i = 0; i < invoke->getNumArgOperands(); i++) {
args.push_back(invoke->getArgOperand(i));
}
this->handle_invoke_call_inst(invoke, cv, &args, parent_func);
}
break;
case Instruction::Call:
{
CallInst * callinst = (CallInst*) inst;
if (callinst->isInlineAsm()) {
break;
}
Value * cv = callinst->getCalledValue();
vector<Value*> args;
for (unsigned i = 0; i < callinst->getNumArgOperands(); i++) {
args.push_back(callinst->getArgOperand(i));
}
this->handle_invoke_call_inst(callinst, cv, &args, parent_func);
}
break;
case Instruction::PHI:
{
PHINode *phi = (PHINode *) inst;
int nums = phi->getNumIncomingValues();
for (int i = 0; i < nums; i++) {
Value * p = phi->getIncomingValue(i);
makeAlias(wrapValue(inst), wrapValue(p));
}
}
break;
case Instruction::Select:
{
Value *first = ((SelectInst*) inst)->getTrueValue();
Value *second = ((SelectInst*) inst)->getFalseValue();
makeAlias(wrapValue(inst), wrapValue(first));
makeAlias(wrapValue(inst), wrapValue(second));
}
break;
case Instruction::VAArg:
{
parent_func->addVAArg(inst);
DyckVertex* vaarg = wrapValue(inst);
Value * ptrVaarg = inst->getOperand(0);
addPtrTo(wrapValue(ptrVaarg), vaarg);
}
break;
case Instruction::LandingPad: // handled with invoke inst
case Instruction::ICmp:
case Instruction::FCmp:
default:
break;
}
}
