+INITIALIZE_ANALYSIS_GROUP(AliasAnalysis, "Alias Analysis", NoAA)
+char AliasAnalysis::ID = 0;
+
+//===----------------------------------------------------------------------===//
+// Default chaining methods
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::AliasResult
+AliasAnalysis::alias(const Location &LocA, const Location &LocB) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->alias(LocA, LocB);
+}
+
+bool AliasAnalysis::pointsToConstantMemory(const Location &Loc,
+ bool OrLocal) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->pointsToConstantMemory(Loc, OrLocal);
+}
+
+void AliasAnalysis::deleteValue(Value *V) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ AA->deleteValue(V);
+}
+
+void AliasAnalysis::copyValue(Value *From, Value *To) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ AA->copyValue(From, To);
+}
+
+void AliasAnalysis::addEscapingUse(Use &U) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ AA->addEscapingUse(U);
+}
+
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
+ const Location &Loc) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ if (MRB == DoesNotAccessMemory)
+ return NoModRef;
+
+ ModRefResult Mask = ModRef;
+ if (onlyReadsMemory(MRB))
+ Mask = Ref;
+
+ if (onlyAccessesArgPointees(MRB)) {
+ bool doesAlias = false;
+ if (doesAccessArgPointees(MRB)) {
+ MDNode *CSTag = CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa);
+ for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+ AI != AE; ++AI) {
+ const Value *Arg = *AI;
+ if (!Arg->getType()->isPointerTy())
+ continue;
+ Location CSLoc(Arg, UnknownSize, CSTag);
+ if (!isNoAlias(CSLoc, Loc)) {
+ doesAlias = true;
+ break;
+ }
+ }
+ }
+ if (!doesAlias)
+ return NoModRef;
+ }
+
+ // If Loc is a constant memory location, the call definitely could not
+ // modify the memory location.
+ if ((Mask & Mod) && pointsToConstantMemory(Loc))
+ Mask = ModRefResult(Mask & ~Mod);
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Mask;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any mask we've managed to compute.
+ return ModRefResult(AA->getModRefInfo(CS, Loc) & Mask);
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+
+ // If CS1 or CS2 are readnone, they don't interact.
+ ModRefBehavior CS1B = getModRefBehavior(CS1);
+ if (CS1B == DoesNotAccessMemory) return NoModRef;
+
+ ModRefBehavior CS2B = getModRefBehavior(CS2);
+ if (CS2B == DoesNotAccessMemory) return NoModRef;
+
+ // If they both only read from memory, there is no dependence.
+ if (onlyReadsMemory(CS1B) && onlyReadsMemory(CS2B))
+ return NoModRef;
+
+ AliasAnalysis::ModRefResult Mask = ModRef;
+
+ // If CS1 only reads memory, the only dependence on CS2 can be
+ // from CS1 reading memory written by CS2.
+ if (onlyReadsMemory(CS1B))
+ Mask = ModRefResult(Mask & Ref);
+
+ // If CS2 only access memory through arguments, accumulate the mod/ref
+ // information from CS1's references to the memory referenced by
+ // CS2's arguments.
+ if (onlyAccessesArgPointees(CS2B)) {
+ AliasAnalysis::ModRefResult R = NoModRef;
+ if (doesAccessArgPointees(CS2B)) {
+ MDNode *CS2Tag = CS2.getInstruction()->getMetadata(LLVMContext::MD_tbaa);
+ for (ImmutableCallSite::arg_iterator
+ I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) {
+ const Value *Arg = *I;
+ if (!Arg->getType()->isPointerTy())
+ continue;
+ Location CS2Loc(Arg, UnknownSize, CS2Tag);
+ R = ModRefResult((R | getModRefInfo(CS1, CS2Loc)) & Mask);
+ if (R == Mask)
+ break;
+ }
+ }
+ return R;
+ }
+
+ // If CS1 only accesses memory through arguments, check if CS2 references
+ // any of the memory referenced by CS1's arguments. If not, return NoModRef.
+ if (onlyAccessesArgPointees(CS1B)) {
+ AliasAnalysis::ModRefResult R = NoModRef;
+ if (doesAccessArgPointees(CS1B)) {
+ MDNode *CS1Tag = CS1.getInstruction()->getMetadata(LLVMContext::MD_tbaa);
+ for (ImmutableCallSite::arg_iterator
+ I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I) {
+ const Value *Arg = *I;
+ if (!Arg->getType()->isPointerTy())
+ continue;
+ Location CS1Loc(Arg, UnknownSize, CS1Tag);
+ if (getModRefInfo(CS2, CS1Loc) != NoModRef) {
+ R = Mask;
+ break;
+ }
+ }
+ }
+ if (R == NoModRef)
+ return R;
+ }
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Mask;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any mask we've managed to compute.
+ return ModRefResult(AA->getModRefInfo(CS1, CS2) & Mask);
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+
+ ModRefBehavior Min = UnknownModRefBehavior;
+
+ // Call back into the alias analysis with the other form of getModRefBehavior
+ // to see if it can give a better response.
+ if (const Function *F = CS.getCalledFunction())
+ Min = getModRefBehavior(F);
+
+ // If this is the end of the chain, don't forward.
+ if (!AA) return Min;
+
+ // Otherwise, fall back to the next AA in the chain. But we can merge
+ // in any result we've managed to compute.
+ return ModRefBehavior(AA->getModRefBehavior(CS) & Min);
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(const Function *F) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->getModRefBehavior(F);
+}
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis non-virtual helper method implementation
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::Location AliasAnalysis::getLocation(const LoadInst *LI) {
+ return Location(LI->getPointerOperand(),
+ getTypeStoreSize(LI->getType()),
+ LI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location AliasAnalysis::getLocation(const StoreInst *SI) {
+ return Location(SI->getPointerOperand(),
+ getTypeStoreSize(SI->getValueOperand()->getType()),
+ SI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location AliasAnalysis::getLocation(const VAArgInst *VI) {
+ return Location(VI->getPointerOperand(),
+ UnknownSize,
+ VI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location
+AliasAnalysis::getLocation(const AtomicCmpXchgInst *CXI) {
+ return Location(CXI->getPointerOperand(),
+ getTypeStoreSize(CXI->getCompareOperand()->getType()),
+ CXI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location
+AliasAnalysis::getLocation(const AtomicRMWInst *RMWI) {
+ return Location(RMWI->getPointerOperand(),
+ getTypeStoreSize(RMWI->getValOperand()->getType()),
+ RMWI->getMetadata(LLVMContext::MD_tbaa));
+}
+
+AliasAnalysis::Location
+AliasAnalysis::getLocationForSource(const MemTransferInst *MTI) {
+ uint64_t Size = UnknownSize;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(MTI->getLength()))
+ Size = C->getValue().getZExtValue();
+
+ // memcpy/memmove can have TBAA tags. For memcpy, they apply
+ // to both the source and the destination.
+ MDNode *TBAATag = MTI->getMetadata(LLVMContext::MD_tbaa);
+
+ return Location(MTI->getRawSource(), Size, TBAATag);
+}
+
+AliasAnalysis::Location
+AliasAnalysis::getLocationForDest(const MemIntrinsic *MTI) {
+ uint64_t Size = UnknownSize;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(MTI->getLength()))
+ Size = C->getValue().getZExtValue();
+
+ // memcpy/memmove can have TBAA tags. For memcpy, they apply
+ // to both the source and the destination.
+ MDNode *TBAATag = MTI->getMetadata(LLVMContext::MD_tbaa);
+
+ return Location(MTI->getRawDest(), Size, TBAATag);