-FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm, bool fast) {
- return new DwarfEHPrepare(tm, fast);
-}
-
-/// PromoteAlloca - This promotes an alloca to registers when we know that it
-/// only has non-volatile loads and stores to it.
-static void PromoteAlloca(AllocaInst *AI) {
- assert(isAllocaPromotable(AI));
-
- // First step: bucket up uses of the pointers by the block they occur in.
- // This is important because we have to handle multiple defs/uses in a block
- // ourselves: SSAUpdater is purely for cross-block references.
- // FIXME: Want a TinyVector<Instruction*> since there is usually 0/1 element.
- DenseMap<BasicBlock*, std::vector<Instruction*> > UsesByBlock;
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- UsesByBlock[User->getParent()].push_back(User);
- }
-
- SSAUpdater SSA;
-
- // It wants to know some value of the same type as what we'll be inserting.
- Value *SomeValue;
- if (isa<LoadInst>(*AI->use_begin()))
- SomeValue = *AI->use_begin();
- else
- SomeValue = cast<StoreInst>(*AI->use_begin())->getOperand(0);
- SSA.Initialize(SomeValue);
-
- // Okay, now we can iterate over all the blocks in the loop with uses,
- // processing them. Keep track of which loads are loading a live-in value.
- SmallVector<LoadInst*, 32> LiveInLoads;
-
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- std::vector<Instruction*> &BlockUses = UsesByBlock[User->getParent()];
-
- // If this block has already been processed, ignore this repeat use.
- if (BlockUses.empty()) continue;
-
- // Okay, this is the first use in the block. If this block just has a
- // single user in it, we can rewrite it trivially.
- if (BlockUses.size() == 1) {
- // If it is a store, it is a trivial def of the value in the block.
- if (isa<StoreInst>(User)) {
- SSA.AddAvailableValue(User->getParent(),
- cast<StoreInst>(User)->getOperand(0));
- } else {
- // Otherwise it is a load, queue it to rewrite as a live-in load.
- LiveInLoads.push_back(cast<LoadInst>(User));
- }
- BlockUses.clear();
- continue;
- }
-
- // Otherwise, check to see if this block is all loads. If so, we can queue
- // them all as live in loads.
- bool HasStore = false;
- for (unsigned i = 0, e = BlockUses.size(); i != e; ++i) {
- if (isa<StoreInst>(BlockUses[i])) {
- HasStore = true;
- break;
- }
- }
-
- if (!HasStore) {
- for (unsigned i = 0, e = BlockUses.size(); i != e; ++i)
- LiveInLoads.push_back(cast<LoadInst>(BlockUses[i]));
- BlockUses.clear();
- continue;
- }
-
- // Otherwise, we have mixed loads and stores (or just a bunch of stores).
- // Since SSAUpdater is purely for cross-block values, we need to determine
- // the order of these instructions in the block. If the first use in the
- // block is a load, then it uses the live in value. The last store defines
- // the live out value. We handle this by doing a linear scan of the block.
- BasicBlock *BB = User->getParent();
- Value *StoredValue = 0;
- for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
- if (LoadInst *L = dyn_cast<LoadInst>(II)) {
- // If this is a load to an unrelated pointer, ignore it.
- if (L->getOperand(0) != AI) continue;
-
- // If we haven't seen a store yet, this is a live in use, otherwise
- // use the stored value.
- if (StoredValue)
- L->replaceAllUsesWith(StoredValue);
- else
- LiveInLoads.push_back(L);
- continue;
- }
-
- if (StoreInst *S = dyn_cast<StoreInst>(II)) {
- // If this is a store to an unrelated pointer, ignore it.
- if (S->getOperand(1) != AI) continue;
-
- // Remember that this is the active value in the block.
- StoredValue = S->getOperand(0);
- }
- }
-
- // The last stored value that happened is the live-out for the block.
- assert(StoredValue && "Already checked that there is a store in block");
- SSA.AddAvailableValue(BB, StoredValue);
- BlockUses.clear();
- }
-
- // Okay, now we rewrite all loads that use live-in values in the loop,
- // inserting PHI nodes as necessary.
- for (unsigned i = 0, e = LiveInLoads.size(); i != e; ++i) {
- LoadInst *ALoad = LiveInLoads[i];
- ALoad->replaceAllUsesWith(SSA.GetValueInMiddleOfBlock(ALoad->getParent()));
- }
-
- // Now that everything is rewritten, delete the old instructions from the body
- // of the loop. They should all be dead now.
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E; ++UI)
- cast<Instruction>(*UI)->eraseFromParent();
-}
-
-
-
-/// HasCatchAllInSelector - Return true if the intrinsic instruction has a
-/// catch-all.
-bool DwarfEHPrepare::HasCatchAllInSelector(IntrinsicInst *II) {
- if (!EHCatchAllValue) return false;
-
- unsigned ArgIdx = II->getNumArgOperands() - 1;
- GlobalVariable *GV = dyn_cast<GlobalVariable>(II->getArgOperand(ArgIdx));
- return GV == EHCatchAllValue;
-}
-
-/// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
-void DwarfEHPrepare::
-FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
- SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels) {
- for (Value::use_iterator
- I = SelectorIntrinsic->use_begin(),
- E = SelectorIntrinsic->use_end(); I != E; ++I) {
- IntrinsicInst *II = cast<IntrinsicInst>(*I);
-
- if (II->getParent()->getParent() != F)
- continue;
-
- if (!HasCatchAllInSelector(II))
- Sels.insert(II);
- else
- CatchAllSels.insert(II);
- }
-}
-
-/// FindAllURoRInvokes - Find all URoR invokes in the function.
-void DwarfEHPrepare::
-FindAllURoRInvokes(SmallPtrSet<InvokeInst*, 32> &URoRInvokes) {
- for (Value::use_iterator
- I = URoR->use_begin(),
- E = URoR->use_end(); I != E; ++I) {
- if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
- URoRInvokes.insert(II);
- }
-}
-
-/// CleanupSelectors - Any remaining eh.selector intrinsic calls which still use
-/// the "llvm.eh.catch.all.value" call need to convert to using its
-/// initializer instead.
-bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
- if (!EHCatchAllValue) return false;
-
- if (!SelectorIntrinsic) {
- SelectorIntrinsic =
- Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
- if (!SelectorIntrinsic) return false;
- }
-
- bool Changed = false;
- for (SmallPtrSet<IntrinsicInst*, 32>::iterator
- I = Sels.begin(), E = Sels.end(); I != E; ++I) {
- IntrinsicInst *Sel = *I;
-
- // Index of the "llvm.eh.catch.all.value" variable.
- unsigned OpIdx = Sel->getNumArgOperands() - 1;
- GlobalVariable *GV = dyn_cast<GlobalVariable>(Sel->getArgOperand(OpIdx));
- if (GV != EHCatchAllValue) continue;
- Sel->setArgOperand(OpIdx, EHCatchAllValue->getInitializer());
- Changed = true;
- }
-
- return Changed;
-}
-
-/// FindSelectorAndURoR - Find the eh.selector call associated with the
-/// eh.exception call. And indicate if there is a URoR "invoke" associated with
-/// the eh.exception call. This recursively looks past instructions which don't
-/// change the EH pointer value, like casts or PHI nodes.
-bool
-DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
- SmallPtrSet<IntrinsicInst*, 8> &SelCalls) {
- SmallPtrSet<PHINode*, 32> SeenPHIs;
- bool Changed = false;
-
- restart:
- for (Value::use_iterator
- I = Inst->use_begin(), E = Inst->use_end(); I != E; ++I) {
- Instruction *II = dyn_cast<Instruction>(*I);
- if (!II || II->getParent()->getParent() != F) continue;
-
- if (IntrinsicInst *Sel = dyn_cast<IntrinsicInst>(II)) {
- if (Sel->getIntrinsicID() == Intrinsic::eh_selector)
- SelCalls.insert(Sel);
- } else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(II)) {
- if (Invoke->getCalledFunction() == URoR)
- URoRInvoke = true;
- } else if (CastInst *CI = dyn_cast<CastInst>(II)) {
- Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls);
- } else if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
- if (!PromoteStoreInst(SI)) continue;
- Changed = true;
- SeenPHIs.clear();
- goto restart; // Uses may have changed, restart loop.
- } else if (PHINode *PN = dyn_cast<PHINode>(II)) {
- if (SeenPHIs.insert(PN))
- // Don't process a PHI node more than once.
- Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls);
- }
- }
-
- return Changed;
-}
-
-/// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" calls. The
-/// "unwind" part of these invokes jump to a landing pad within the current
-/// function. This is a candidate to merge the selector associated with the URoR
-/// invoke with the one from the URoR's landing pad.
-bool DwarfEHPrepare::HandleURoRInvokes() {
- if (!EHCatchAllValue) {
- EHCatchAllValue =
- F->getParent()->getNamedGlobal("llvm.eh.catch.all.value");
- if (!EHCatchAllValue) return false;
- }
-
- if (!SelectorIntrinsic) {
- SelectorIntrinsic =
- Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
- if (!SelectorIntrinsic) return false;
- }
-
- SmallPtrSet<IntrinsicInst*, 32> Sels;
- SmallPtrSet<IntrinsicInst*, 32> CatchAllSels;
- FindAllCleanupSelectors(Sels, CatchAllSels);
-
- if (!DT)
- // We require DominatorTree information.
- return CleanupSelectors(CatchAllSels);
-
- if (!URoR) {
- URoR = F->getParent()->getFunction("_Unwind_Resume_or_Rethrow");
- if (!URoR) return CleanupSelectors(CatchAllSels);
- }
-
- SmallPtrSet<InvokeInst*, 32> URoRInvokes;
- FindAllURoRInvokes(URoRInvokes);
-
- SmallPtrSet<IntrinsicInst*, 32> SelsToConvert;
-
- for (SmallPtrSet<IntrinsicInst*, 32>::iterator
- SI = Sels.begin(), SE = Sels.end(); SI != SE; ++SI) {
- const BasicBlock *SelBB = (*SI)->getParent();
- for (SmallPtrSet<InvokeInst*, 32>::iterator
- UI = URoRInvokes.begin(), UE = URoRInvokes.end(); UI != UE; ++UI) {
- const BasicBlock *URoRBB = (*UI)->getParent();
- if (DT->dominates(SelBB, URoRBB)) {
- SelsToConvert.insert(*SI);
- break;
- }
- }
- }
-
- bool Changed = false;
-
- if (Sels.size() != SelsToConvert.size()) {
- // If we haven't been able to convert all of the clean-up selectors, then
- // loop through the slow way to see if they still need to be converted.
- if (!ExceptionValueIntrinsic) {
- ExceptionValueIntrinsic =
- Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_exception);
- if (!ExceptionValueIntrinsic)
- return CleanupSelectors(CatchAllSels);
- }
-
- for (Value::use_iterator
- I = ExceptionValueIntrinsic->use_begin(),
- E = ExceptionValueIntrinsic->use_end(); I != E; ++I) {
- IntrinsicInst *EHPtr = dyn_cast<IntrinsicInst>(*I);
- if (!EHPtr || EHPtr->getParent()->getParent() != F) continue;
-
- Changed |= PromoteEHPtrStore(EHPtr);
-
- bool URoRInvoke = false;
- SmallPtrSet<IntrinsicInst*, 8> SelCalls;
- Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
-
- if (URoRInvoke) {
- // This EH pointer is being used by an invoke of an URoR instruction and
- // an eh.selector intrinsic call. If the eh.selector is a 'clean-up', we
- // need to convert it to a 'catch-all'.
- for (SmallPtrSet<IntrinsicInst*, 8>::iterator
- SI = SelCalls.begin(), SE = SelCalls.end(); SI != SE; ++SI)
- if (!HasCatchAllInSelector(*SI))
- SelsToConvert.insert(*SI);