+SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
+ // too complex to analyze statically.
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
+ SizeOffsetType TrueSide = compute(I.getTrueValue());
+ SizeOffsetType FalseSide = compute(I.getFalseValue());
+ if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
+ return TrueSide;
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
+ return std::make_pair(Zero, Zero);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
+ DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I << '\n');
+ return unknown();
+}
+
+ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ LLVMContext &Context,
+ bool RoundToAlign)
+: DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)),
+ RoundToAlign(RoundToAlign) {
+ // IntTy and Zero must be set for each compute() since the address space may
+ // be different for later objects.
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
+ // XXX - Are vectors of pointers possible here?
+ IntTy = cast<IntegerType>(DL->getIntPtrType(V->getType()));
+ Zero = ConstantInt::get(IntTy, 0);
+
+ SizeOffsetEvalType Result = compute_(V);
+
+ if (!bothKnown(Result)) {
+ // erase everything that was computed in this iteration from the cache, so
+ // that no dangling references are left behind. We could be a bit smarter if
+ // we kept a dependency graph. It's probably not worth the complexity.
+ for (PtrSetTy::iterator I=SeenVals.begin(), E=SeenVals.end(); I != E; ++I) {
+ CacheMapTy::iterator CacheIt = CacheMap.find(*I);
+ // non-computable results can be safely cached
+ if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
+ CacheMap.erase(CacheIt);
+ }
+ }
+
+ SeenVals.clear();
+ return Result;
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
+ ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, RoundToAlign);
+ SizeOffsetType Const = Visitor.compute(V);
+ if (Visitor.bothKnown(Const))
+ return std::make_pair(ConstantInt::get(Context, Const.first),
+ ConstantInt::get(Context, Const.second));
+
+ V = V->stripPointerCasts();
+
+ // check cache
+ CacheMapTy::iterator CacheIt = CacheMap.find(V);
+ if (CacheIt != CacheMap.end())
+ return CacheIt->second;
+
+ // always generate code immediately before the instruction being
+ // processed, so that the generated code dominates the same BBs
+ Instruction *PrevInsertPoint = Builder.GetInsertPoint();
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ Builder.SetInsertPoint(I);
+
+ // now compute the size and offset
+ SizeOffsetEvalType Result;
+
+ // Record the pointers that were handled in this run, so that they can be
+ // cleaned later if something fails. We also use this set to break cycles that
+ // can occur in dead code.
+ if (!SeenVals.insert(V)) {
+ Result = unknown();
+ } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ Result = visitGEPOperator(*GEP);
+ } else if (Instruction *I = dyn_cast<Instruction>(V)) {
+ Result = visit(*I);
+ } else if (isa<Argument>(V) ||
+ (isa<ConstantExpr>(V) &&
+ cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
+ isa<GlobalAlias>(V) ||
+ isa<GlobalVariable>(V)) {
+ // ignore values where we cannot do more than what ObjectSizeVisitor can
+ Result = unknown();
+ } else {
+ DEBUG(dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: "
+ << *V << '\n');
+ Result = unknown();
+ }
+
+ if (PrevInsertPoint)
+ Builder.SetInsertPoint(PrevInsertPoint);
+
+ // Don't reuse CacheIt since it may be invalid at this point.
+ CacheMap[V] = Result;
+ return Result;
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
+ if (!I.getAllocatedType()->isSized())
+ return unknown();
+
+ // must be a VLA
+ assert(I.isArrayAllocation());
+ Value *ArraySize = I.getArraySize();
+ Value *Size = ConstantInt::get(ArraySize->getType(),
+ DL->getTypeAllocSize(I.getAllocatedType()));
+ Size = Builder.CreateMul(Size, ArraySize);
+ return std::make_pair(Size, Zero);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
+ const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc,
+ TLI);
+ if (!FnData)
+ return unknown();
+
+ // handle strdup-like functions separately
+ if (FnData->AllocTy == StrDupLike) {
+ // TODO
+ return unknown();
+ }
+
+ Value *FirstArg = CS.getArgument(FnData->FstParam);
+ FirstArg = Builder.CreateZExt(FirstArg, IntTy);
+ if (FnData->SndParam < 0)
+ return std::make_pair(FirstArg, Zero);
+
+ Value *SecondArg = CS.getArgument(FnData->SndParam);
+ SecondArg = Builder.CreateZExt(SecondArg, IntTy);
+ Value *Size = Builder.CreateMul(FirstArg, SecondArg);
+ return std::make_pair(Size, Zero);
+
+ // TODO: handle more standard functions (+ wchar cousins):
+ // - strdup / strndup
+ // - strcpy / strncpy
+ // - strcat / strncat
+ // - memcpy / memmove
+ // - strcat / strncat
+ // - memset
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitExtractElementInst(ExtractElementInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
+ SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
+ if (!bothKnown(PtrData))
+ return unknown();
+
+ Value *Offset = EmitGEPOffset(&Builder, *DL, &GEP, /*NoAssumptions=*/true);
+ Offset = Builder.CreateAdd(PtrData.second, Offset);
+ return std::make_pair(PtrData.first, Offset);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
+ // clueless
+ return unknown();
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
+ // create 2 PHIs: one for size and another for offset
+ PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
+ PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
+
+ // insert right away in the cache to handle recursive PHIs
+ CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
+
+ // compute offset/size for each PHI incoming pointer
+ for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
+ Builder.SetInsertPoint(PHI.getIncomingBlock(i)->getFirstInsertionPt());
+ SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
+
+ if (!bothKnown(EdgeData)) {
+ OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
+ OffsetPHI->eraseFromParent();
+ SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
+ SizePHI->eraseFromParent();
+ return unknown();
+ }
+ SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
+ OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
+ }
+
+ Value *Size = SizePHI, *Offset = OffsetPHI, *Tmp;
+ if ((Tmp = SizePHI->hasConstantValue())) {
+ Size = Tmp;
+ SizePHI->replaceAllUsesWith(Size);
+ SizePHI->eraseFromParent();
+ }
+ if ((Tmp = OffsetPHI->hasConstantValue())) {
+ Offset = Tmp;
+ OffsetPHI->replaceAllUsesWith(Offset);
+ OffsetPHI->eraseFromParent();
+ }
+ return std::make_pair(Size, Offset);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
+ SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
+ SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
+
+ if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
+ return unknown();
+ if (TrueSide == FalseSide)
+ return TrueSide;
+
+ Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
+ FalseSide.first);
+ Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
+ FalseSide.second);
+ return std::make_pair(Size, Offset);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
+ DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I <<'\n');
+ return unknown();