bool prepareExceptionHandlers(Function &F,
SmallVectorImpl<LandingPadInst *> &LPads);
void promoteLandingPadValues(LandingPadInst *LPad);
+ void completeNestedLandingPad(Function *ParentFn,
+ LandingPadInst *OutlinedLPad,
+ const LandingPadInst *OriginalLPad,
+ FrameVarInfoMap &VarInfo);
bool outlineHandler(ActionHandler *Action, Function *SrcFn,
LandingPadInst *LPad, BasicBlock *StartBB,
FrameVarInfoMap &VarInfo);
+ void addStubInvokeToHandlerIfNeeded(Function *Handler, Value *PersonalityFn);
void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions);
CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB,
VisitedBlockSet &VisitedBlocks);
- CleanupHandler *findCleanupHandler(BasicBlock *StartBB, BasicBlock *EndBB);
+ void findCleanupHandlers(LandingPadActions &Actions, BasicBlock *StartBB,
+ BasicBlock *EndBB);
void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
CatchHandlerMapTy CatchHandlerMap;
CleanupHandlerMapTy CleanupHandlerMap;
DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps;
+
+ // This maps landing pad instructions found in outlined handlers to
+ // the landing pad instruction in the parent function from which they
+ // were cloned. The cloned/nested landing pad is used as the key
+ // because the landing pad may be cloned into multiple handlers.
+ // This map will be used to add the llvm.eh.actions call to the nested
+ // landing pads after all handlers have been outlined.
+ DenseMap<LandingPadInst *, const LandingPadInst *> NestedLPtoOriginalLP;
+
+ // This maps blocks in the parent function which are destinations of
+ // catch handlers to cloned blocks in (other) outlined handlers. This
+ // handles the case where a nested landing pads has a catch handler that
+ // returns to a handler function rather than the parent function.
+ // The original block is used as the key here because there should only
+ // ever be one handler function from which the cloned block is not pruned.
+ // The original block will be pruned from the parent function after all
+ // handlers have been outlined. This map will be used to adjust the
+ // return instructions of handlers which return to the block that was
+ // outlined into a handler. This is done after all handlers have been
+ // outlined but before the outlined code is pruned from the parent function.
+ DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
};
class WinEHFrameVariableMaterializer : public ValueMaterializer {
public:
WinEHFrameVariableMaterializer(Function *OutlinedFn,
FrameVarInfoMap &FrameVarInfo);
- ~WinEHFrameVariableMaterializer() {}
+ ~WinEHFrameVariableMaterializer() override {}
- virtual Value *materializeValueFor(Value *V) override;
+ Value *materializeValueFor(Value *V) override;
void escapeCatchObject(Value *V);
class WinEHCloningDirectorBase : public CloningDirector {
public:
- WinEHCloningDirectorBase(Function *HandlerFn,
- FrameVarInfoMap &VarInfo,
+ WinEHCloningDirectorBase(Function *HandlerFn, FrameVarInfoMap &VarInfo,
LandingPadMap &LPadMap)
: Materializer(HandlerFn, VarInfo),
SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
virtual CloningAction handleResume(ValueToValueMapTy &VMap,
const ResumeInst *Resume,
BasicBlock *NewBB) = 0;
+ virtual CloningAction handleLandingPad(ValueToValueMapTy &VMap,
+ const LandingPadInst *LPad,
+ BasicBlock *NewBB) = 0;
ValueMaterializer *getValueMaterializer() override { return &Materializer; }
class WinEHCatchDirector : public WinEHCloningDirectorBase {
public:
- WinEHCatchDirector(Function *CatchFn, Value *Selector,
- FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
+ WinEHCatchDirector(
+ Function *CatchFn, Value *Selector, FrameVarInfoMap &VarInfo,
+ LandingPadMap &LPadMap,
+ DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads)
: WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap),
CurrentSelector(Selector->stripPointerCasts()),
- ExceptionObjectVar(nullptr) {}
+ ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads) {}
CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
const Instruction *Inst,
BasicBlock *NewBB) override;
CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
BasicBlock *NewBB) override;
+ CloningAction handleLandingPad(ValueToValueMapTy &VMap,
+ const LandingPadInst *LPad,
+ BasicBlock *NewBB) override;
Value *getExceptionVar() { return ExceptionObjectVar; }
TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
Value *ExceptionObjectVar;
TinyPtrVector<BasicBlock *> ReturnTargets;
+
+ // This will be a reference to the field of the same name in the WinEHPrepare
+ // object which instantiates this WinEHCatchDirector object.
+ DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPtoOriginalLP;
};
class WinEHCleanupDirector : public WinEHCloningDirectorBase {
public:
- WinEHCleanupDirector(Function *CleanupFn,
- FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
+ WinEHCleanupDirector(Function *CleanupFn, FrameVarInfoMap &VarInfo,
+ LandingPadMap &LPadMap)
: WinEHCloningDirectorBase(CleanupFn, VarInfo, LPadMap) {}
CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
BasicBlock *NewBB) override;
CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
BasicBlock *NewBB) override;
+ CloningAction handleLandingPad(ValueToValueMapTy &VMap,
+ const LandingPadInst *LPad,
+ BasicBlock *NewBB) override;
};
class LandingPadActions {
// FIXME: Remove this once the backend can handle the prepared IR.
static cl::opt<bool>
-SEHPrepare("sehprepare", cl::Hidden,
- cl::desc("Prepare functions with SEH personalities"));
+ SEHPrepare("sehprepare", cl::Hidden,
+ cl::desc("Prepare functions with SEH personalities"));
bool WinEHPrepare::runOnFunction(Function &Fn) {
SmallVector<LandingPadInst *, 4> LPads;
return true;
}
-bool WinEHPrepare::doFinalization(Module &M) {
- return false;
-}
+bool WinEHPrepare::doFinalization(Module &M) { return false; }
void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTreeWrapperPass>();
LandingPadActions Actions;
mapLandingPadBlocks(LPad, Actions);
+ HandlersOutlined |= !Actions.actions().empty();
for (ActionHandler *Action : Actions) {
if (Action->hasBeenProcessed())
continue;
if (isAsynchronousEHPersonality(Personality)) {
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
processSEHCatchHandler(CatchAction, StartBB);
- HandlersOutlined = true;
continue;
}
}
- if (outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo)) {
- HandlersOutlined = true;
- }
- } // End for each Action
-
- // FIXME: We need a guard against partially outlined functions.
- if (!HandlersOutlined)
- continue;
+ outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo);
+ }
// Replace the landing pad with a new llvm.eh.action based landing pad.
BasicBlock *NewLPadBB = BasicBlock::Create(Context, "lpad", &F, LPadBB);
Invoke->setUnwindDest(NewLPadBB);
}
+ // If anyone is still using the old landingpad value, just give them undef
+ // instead. The eh pointer and selector values are not real.
+ LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
+
+ // Replace the mapping of any nested landing pad that previously mapped
+ // to this landing pad with a referenced to the cloned version.
+ for (auto &LPadPair : NestedLPtoOriginalLP) {
+ const LandingPadInst *OriginalLPad = LPadPair.second;
+ if (OriginalLPad == LPad) {
+ LPadPair.second = NewLPad;
+ }
+ }
+
// Replace uses of the old lpad in phis with this block and delete the old
// block.
LPadBB->replaceSuccessorsPhiUsesWith(NewLPadBB);
if (!HandlersOutlined)
return false;
+ // Replace any nested landing pad stubs with the correct action handler.
+ // This must be done before we remove unreachable blocks because it
+ // cleans up references to outlined blocks that will be deleted.
+ for (auto &LPadPair : NestedLPtoOriginalLP)
+ completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo);
+ NestedLPtoOriginalLP.clear();
+
F.addFnAttr("wineh-parent", F.getName());
// Delete any blocks that were only used by handlers that were outlined above.
++InsertPt;
ParentAlloca =
new AllocaInst(ParentInst->getType(), nullptr,
- ParentInst->getName() + ".reg2mem", InsertPt);
+ ParentInst->getName() + ".reg2mem",
+ AllocaInsertPt);
new StoreInst(ParentInst, ParentAlloca, InsertPt);
} else {
- ParentAlloca = DemoteRegToStack(*ParentInst, true, ParentInst);
+ ParentAlloca = DemoteRegToStack(*ParentInst, true, AllocaInsertPt);
}
}
}
- // If the parent alloca is used by exactly one handler and is not a catch
- // parameter, erase the parent and leave the copy in the outlined handler.
- // Catch parameters are indicated by a single null pointer in Allocas.
- if (ParentAlloca->getNumUses() == 0 && Allocas.size() == 1 &&
- Allocas[0] != getCatchObjectSentinel()) {
- ParentAlloca->eraseFromParent();
- // FIXME: Put a null entry in the llvm.frameescape call because we've
- // already created llvm.eh.actions calls with indices into it.
- AllocasToEscape.push_back(Constant::getNullValue(Int8PtrType));
- continue;
- }
+ // FIXME: We should try to sink unescaped allocas from the parent frame into
+ // the child frame. If the alloca is escaped, we have to use the lifetime
+ // markers to ensure that the alloca is only live within the child frame.
// Add this alloca to the list of things to escape.
AllocasToEscape.push_back(ParentAlloca);
Builder.SetInsertPoint(&F.getEntryBlock().back());
Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
- // Insert an alloca for the EH state in the entry block. On x86, we will also
- // insert stores to update the EH state, but on other ISAs, the runtime does
- // it for us.
- // FIXME: This record is different on x86.
- Type *UnwindHelpTy = Type::getInt64Ty(Context);
- AllocaInst *UnwindHelp =
- new AllocaInst(UnwindHelpTy, "unwindhelp", &F.getEntryBlock().front());
- Builder.CreateStore(llvm::ConstantInt::get(UnwindHelpTy, -2), UnwindHelp,
- /*isVolatile=*/true);
- Function *UnwindHelpFn =
- Intrinsic::getDeclaration(M, Intrinsic::eh_unwindhelp);
- Builder.CreateCall(UnwindHelpFn,
- Builder.CreateBitCast(UnwindHelp, Int8PtrType));
-
// Clean up the handler action maps we created for this function
DeleteContainerSeconds(CatchHandlerMap);
CatchHandlerMap.clear();
PromoteMemToReg(EHAllocas, *DT);
EHAllocas.clear();
}
+
+ // After promotion, some extracts may be trivially dead. Remove them.
+ SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end());
+ for (auto *U : Users)
+ RecursivelyDeleteTriviallyDeadInstructions(U);
+}
+
+void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
+ LandingPadInst *OutlinedLPad,
+ const LandingPadInst *OriginalLPad,
+ FrameVarInfoMap &FrameVarInfo) {
+ // Get the nested block and erase the unreachable instruction that was
+ // temporarily inserted as its terminator.
+ LLVMContext &Context = ParentFn->getContext();
+ BasicBlock *OutlinedBB = OutlinedLPad->getParent();
+ assert(isa<UnreachableInst>(OutlinedBB->getTerminator()));
+ OutlinedBB->getTerminator()->eraseFromParent();
+ // That should leave OutlinedLPad as the last instruction in its block.
+ assert(&OutlinedBB->back() == OutlinedLPad);
+
+ // The original landing pad will have already had its action intrinsic
+ // built by the outlining loop. We need to clone that into the outlined
+ // location. It may also be necessary to add references to the exception
+ // variables to the outlined handler in which this landing pad is nested
+ // and remap return instructions in the nested handlers that should return
+ // to an address in the outlined handler.
+ Function *OutlinedHandlerFn = OutlinedBB->getParent();
+ BasicBlock::const_iterator II = OriginalLPad;
+ ++II;
+ // The instruction after the landing pad should now be a call to eh.actions.
+ const Instruction *Recover = II;
+ assert(match(Recover, m_Intrinsic<Intrinsic::eh_actions>()));
+ IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover->clone());
+
+ // Remap the exception variables into the outlined function.
+ WinEHFrameVariableMaterializer Materializer(OutlinedHandlerFn, FrameVarInfo);
+ SmallVector<BlockAddress *, 4> ActionTargets;
+ SmallVector<ActionHandler *, 4> ActionList;
+ parseEHActions(EHActions, ActionList);
+ for (auto *Action : ActionList) {
+ auto *Catch = dyn_cast<CatchHandler>(Action);
+ if (!Catch)
+ continue;
+ // The dyn_cast to function here selects C++ catch handlers and skips
+ // SEH catch handlers.
+ auto *Handler = dyn_cast<Function>(Catch->getHandlerBlockOrFunc());
+ if (!Handler)
+ continue;
+ // Visit all the return instructions, looking for places that return
+ // to a location within OutlinedHandlerFn.
+ for (BasicBlock &NestedHandlerBB : *Handler) {
+ auto *Ret = dyn_cast<ReturnInst>(NestedHandlerBB.getTerminator());
+ if (!Ret)
+ continue;
+
+ // Handler functions must always return a block address.
+ BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
+ // The original target will have been in the main parent function,
+ // but if it is the address of a block that has been outlined, it
+ // should be a block that was outlined into OutlinedHandlerFn.
+ assert(BA->getFunction() == ParentFn);
+
+ // Ignore targets that aren't part of OutlinedHandlerFn.
+ if (!LPadTargetBlocks.count(BA->getBasicBlock()))
+ continue;
+
+ // If the return value is the address ofF a block that we
+ // previously outlined into the parent handler function, replace
+ // the return instruction and add the mapped target to the list
+ // of possible return addresses.
+ BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()];
+ assert(MappedBB->getParent() == OutlinedHandlerFn);
+ BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB);
+ Ret->eraseFromParent();
+ ReturnInst::Create(Context, NewBA, &NestedHandlerBB);
+ ActionTargets.push_back(NewBA);
+ }
+ }
+ DeleteContainerPointers(ActionList);
+ ActionList.clear();
+ OutlinedBB->getInstList().push_back(EHActions);
+
+ // Insert an indirect branch into the outlined landing pad BB.
+ IndirectBrInst *IBr = IndirectBrInst::Create(EHActions, 0, OutlinedBB);
+ // Add the previously collected action targets.
+ for (auto *Target : ActionTargets)
+ IBr->addDestination(Target->getBasicBlock());
}
// This function examines a block to determine whether the block ends with a
return false;
}
+static BasicBlock *createStubLandingPad(Function *Handler,
+ Value *PersonalityFn) {
+ // FIXME: Finish this!
+ LLVMContext &Context = Handler->getContext();
+ BasicBlock *StubBB = BasicBlock::Create(Context, "stub");
+ Handler->getBasicBlockList().push_back(StubBB);
+ IRBuilder<> Builder(StubBB);
+ LandingPadInst *LPad = Builder.CreateLandingPad(
+ llvm::StructType::get(Type::getInt8PtrTy(Context),
+ Type::getInt32Ty(Context), nullptr),
+ PersonalityFn, 0);
+ LPad->setCleanup(true);
+ Builder.CreateUnreachable();
+ return StubBB;
+}
+
+// Cycles through the blocks in an outlined handler function looking for an
+// invoke instruction and inserts an invoke of llvm.donothing with an empty
+// landing pad if none is found. The code that generates the .xdata tables for
+// the handler needs at least one landing pad to identify the parent function's
+// personality.
+void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler,
+ Value *PersonalityFn) {
+ ReturnInst *Ret = nullptr;
+ for (BasicBlock &BB : *Handler) {
+ TerminatorInst *Terminator = BB.getTerminator();
+ // If we find an invoke, there is nothing to be done.
+ auto *II = dyn_cast<InvokeInst>(Terminator);
+ if (II)
+ return;
+ // If we've already recorded a return instruction, keep looking for invokes.
+ if (Ret)
+ continue;
+ // If we haven't recorded a return instruction yet, try this terminator.
+ Ret = dyn_cast<ReturnInst>(Terminator);
+ }
+
+ // If we got this far, the handler contains no invokes. We should have seen
+ // at least one return. We'll insert an invoke of llvm.donothing ahead of
+ // that return.
+ assert(Ret);
+ BasicBlock *OldRetBB = Ret->getParent();
+ BasicBlock *NewRetBB = SplitBlock(OldRetBB, Ret);
+ // SplitBlock adds an unconditional branch instruction at the end of the
+ // parent block. We want to replace that with an invoke call, so we can
+ // erase it now.
+ OldRetBB->getTerminator()->eraseFromParent();
+ BasicBlock *StubLandingPad = createStubLandingPad(Handler, PersonalityFn);
+ Function *F =
+ Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing);
+ InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB);
+}
+
bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
LandingPadInst *LPad, BasicBlock *StartBB,
FrameVarInfoMap &VarInfo) {
LPadMap.mapLandingPad(LPad);
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
Constant *Sel = CatchAction->getSelector();
- Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap));
+ Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap,
+ NestedLPtoOriginalLP));
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
ConstantInt::get(Type::getInt32Ty(Context), 1));
} else {
Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList());
FirstClonedBB->eraseFromParent();
+ // Make sure we can identify the handler's personality later.
+ addStubInvokeToHandlerIfNeeded(Handler, LPad->getPersonalityFn());
+
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
WinEHCatchDirector *CatchDirector =
reinterpret_cast<WinEHCatchDirector *>(Director.get());
CatchAction->setExceptionVar(CatchDirector->getExceptionVar());
CatchAction->setReturnTargets(CatchDirector->getReturnTargets());
- }
+
+ // Look for blocks that are not part of the landing pad that we just
+ // outlined but terminate with a call to llvm.eh.endcatch and a
+ // branch to a block that is in the handler we just outlined.
+ // These blocks will be part of a nested landing pad that intends to
+ // return to an address in this handler. This case is best handled
+ // after both landing pads have been outlined, so for now we'll just
+ // save the association of the blocks in LPadTargetBlocks. The
+ // return instructions which are created from these branches will be
+ // replaced after all landing pads have been outlined.
+ for (const auto MapEntry : VMap) {
+ // VMap maps all values and blocks that were just cloned, but dead
+ // blocks which were pruned will map to nullptr.
+ if (!isa<BasicBlock>(MapEntry.first) || MapEntry.second == nullptr)
+ continue;
+ const BasicBlock *MappedBB = cast<BasicBlock>(MapEntry.first);
+ for (auto *Pred : predecessors(const_cast<BasicBlock *>(MappedBB))) {
+ auto *Branch = dyn_cast<BranchInst>(Pred->getTerminator());
+ if (!Branch || !Branch->isUnconditional() || Pred->size() <= 1)
+ continue;
+ BasicBlock::iterator II = const_cast<BranchInst *>(Branch);
+ --II;
+ if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_endcatch>())) {
+ // This would indicate that a nested landing pad wants to return
+ // to a block that is outlined into two different handlers.
+ assert(!LPadTargetBlocks.count(MappedBB));
+ LPadTargetBlocks[MappedBB] = cast<BasicBlock>(MapEntry.second);
+ }
+ }
+ }
+ } // End if (CatchAction)
Action->setHandlerBlockOrFunc(Handler);
// all landingpads have been outlined, we'll replace this with the
// llvm.eh.actions call and indirect branch created when the
// landing pad was outlined.
- if (auto *NestedLPad = dyn_cast<LandingPadInst>(Inst)) {
- Instruction *NewInst = NestedLPad->clone();
- if (NestedLPad->hasName())
- NewInst->setName(NestedLPad->getName());
- // FIXME: Store this mapping somewhere else also.
- VMap[NestedLPad] = NewInst;
- BasicBlock::InstListType &InstList = NewBB->getInstList();
- InstList.push_back(NewInst);
- InstList.push_back(new UnreachableInst(NewBB->getContext()));
- return CloningDirector::StopCloningBB;
+ if (auto *LPad = dyn_cast<LandingPadInst>(Inst)) {
+ return handleLandingPad(VMap, LPad, NewBB);
}
if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
return CloningDirector::CloneInstruction;
}
+CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad(
+ ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
+ Instruction *NewInst = LPad->clone();
+ if (LPad->hasName())
+ NewInst->setName(LPad->getName());
+ // Save this correlation for later processing.
+ NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad;
+ VMap[LPad] = NewInst;
+ BasicBlock::InstListType &InstList = NewBB->getInstList();
+ InstList.push_back(NewInst);
+ InstList.push_back(new UnreachableInst(NewBB->getContext()));
+ return CloningDirector::StopCloningBB;
+}
+
CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
// The argument to the call is some form of the first element of the
return CloningDirector::StopCloningBB;
}
+CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad(
+ ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
+ // The MS runtime will terminate the process if an exception occurs in a
+ // cleanup handler, so we shouldn't encounter landing pads in the actual
+ // cleanup code, but they may appear in catch blocks. Depending on where
+ // we started cloning we may see one, but it will get dropped during dead
+ // block pruning.
+ Instruction *NewInst = new UnreachableInst(NewBB->getContext());
+ VMap[LPad] = NewInst;
+ BasicBlock::InstListType &InstList = NewBB->getInstList();
+ InstList.push_back(NewInst);
+ return CloningDirector::StopCloningBB;
+}
+
CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
// Catch blocks within cleanup handlers will always be unreachable.
CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // Catch blocks within cleanup handlers will always be unreachable.
- // We'll insert an unreachable instruction now, but it will be pruned
- // before the cloning process is complete.
- BasicBlock::InstListType &InstList = NewBB->getInstList();
- InstList.push_back(new UnreachableInst(NewBB->getContext()));
- return CloningDirector::StopCloningBB;
+ // Cleanup handlers nested within catch handlers may begin with a call to
+ // eh.endcatch. We can just ignore that instruction.
+ return CloningDirector::SkipInstruction;
}
CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
NewCall->setDebugLoc(Invoke->getDebugLoc());
VMap[Invoke] = NewCall;
+ // Remap the operands.
+ llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer);
+
// Insert an unconditional branch to the normal destination.
BranchInst::Create(Invoke->getNormalDest(), NewBB);
// We just added a terminator to the cloned block.
// Tell the caller to stop processing the current basic block.
- return CloningDirector::StopCloningBB;
+ return CloningDirector::CloneSuccessors;
}
CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
: FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
- Builder.SetInsertPoint(&OutlinedFn->getEntryBlock());
+ BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
+ Builder.SetInsertPoint(EntryBB, EntryBB->getFirstInsertionPt());
}
Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
DEBUG(dbgs() << "Mapping landing pad: " << BB->getName() << "\n");
if (NumClauses == 0) {
- // This landing pad contains only cleanup code.
- CleanupHandler *Action = new CleanupHandler(BB);
- CleanupHandlerMap[BB] = Action;
- Actions.insertCleanupHandler(Action);
- DEBUG(dbgs() << " Assuming cleanup code in block " << BB->getName()
- << "\n");
- assert(LPad->isCleanup());
+ findCleanupHandlers(Actions, BB, nullptr);
return;
}
// exceptions but code called from catches can. For SEH, it isn't
// important if some finally code before a catch-all is executed out of
// line or after recovering from the exception.
- if (Personality == EHPersonality::MSVC_CXX) {
- if (auto *CleanupAction = findCleanupHandler(BB, BB)) {
- // Add a cleanup entry to the list
- Actions.insertCleanupHandler(CleanupAction);
- DEBUG(dbgs() << " Found cleanup code in block "
- << CleanupAction->getStartBlock()->getName() << "\n");
- }
- }
+ if (Personality == EHPersonality::MSVC_CXX)
+ findCleanupHandlers(Actions, BB, BB);
// Add the catch handler to the action list.
CatchHandler *Action =
CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
// See if there is any interesting code executed before the dispatch.
- if (auto *CleanupAction =
- findCleanupHandler(BB, CatchAction->getStartBlock())) {
- // Add a cleanup entry to the list
- Actions.insertCleanupHandler(CleanupAction);
- DEBUG(dbgs() << " Found cleanup code in block "
- << CleanupAction->getStartBlock()->getName() << "\n");
- }
+ findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
assert(CatchAction);
++HandlersFound;
// If we didn't wind up in a catch-all, see if there is any interesting code
// executed before the resume.
- if (auto *CleanupAction = findCleanupHandler(BB, BB)) {
- // Add a cleanup entry to the list
- Actions.insertCleanupHandler(CleanupAction);
- DEBUG(dbgs() << " Found cleanup code in block "
- << CleanupAction->getStartBlock()->getName() << "\n");
- }
+ findCleanupHandlers(Actions, BB, BB);
// It's possible that some optimization moved code into a landingpad that
// wasn't
return nullptr;
}
-// These are helper functions to combine repeated code from findCleanupHandler.
-static CleanupHandler *createCleanupHandler(CleanupHandlerMapTy &CleanupHandlerMap,
- BasicBlock *BB) {
+// These are helper functions to combine repeated code from findCleanupHandlers.
+static void createCleanupHandler(LandingPadActions &Actions,
+ CleanupHandlerMapTy &CleanupHandlerMap,
+ BasicBlock *BB) {
CleanupHandler *Action = new CleanupHandler(BB);
CleanupHandlerMap[BB] = Action;
- return Action;
+ Actions.insertCleanupHandler(Action);
+ DEBUG(dbgs() << " Found cleanup code in block "
+ << Action->getStartBlock()->getName() << "\n");
+}
+
+static bool isFrameAddressCall(Value *V) {
+ return match(V, m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
+}
+
+static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
+ Instruction *MaybeCall) {
+ // Look for finally blocks that Clang has already outlined for us.
+ // %fp = call i8* @llvm.frameaddress(i32 0)
+ // call void @"fin$parent"(iN 1, i8* %fp)
+ if (isFrameAddressCall(MaybeCall) && MaybeCall != BB->getTerminator())
+ MaybeCall = MaybeCall->getNextNode();
+ CallSite FinallyCall(MaybeCall);
+ if (!FinallyCall || FinallyCall.arg_size() != 2)
+ return CallSite();
+ if (!match(FinallyCall.getArgument(0), m_SpecificInt(1)))
+ return CallSite();
+ if (!isFrameAddressCall(FinallyCall.getArgument(1)))
+ return CallSite();
+ return FinallyCall;
+}
+
+static BasicBlock *followSingleUnconditionalBranches(BasicBlock *BB) {
+ // Skip single ubr blocks.
+ while (BB->getFirstNonPHIOrDbg() == BB->getTerminator()) {
+ auto *Br = dyn_cast<BranchInst>(BB->getTerminator());
+ if (Br && Br->isUnconditional())
+ BB = Br->getSuccessor(0);
+ else
+ return BB;
+ }
+ return BB;
}
// This function searches starting with the input block for the next block that
// contains code that is not part of a catch handler and would not be eliminated
// during handler outlining.
//
-CleanupHandler *WinEHPrepare::findCleanupHandler(BasicBlock *StartBB,
- BasicBlock *EndBB) {
+void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions,
+ BasicBlock *StartBB, BasicBlock *EndBB) {
// Here we will skip over the following:
//
// landing pad prolog:
// Anything other than an unconditional branch will kick us out of this loop
// one way or another.
while (BB) {
+ BB = followSingleUnconditionalBranches(BB);
// If we've already scanned this block, don't scan it again. If it is
// a cleanup block, there will be an action in the CleanupHandlerMap.
// If we've scanned it and it is not a cleanup block, there will be a
// avoid creating a null entry for blocks we haven't scanned.
if (CleanupHandlerMap.count(BB)) {
if (auto *Action = CleanupHandlerMap[BB]) {
- return cast<CleanupHandler>(Action);
+ Actions.insertCleanupHandler(Action);
+ DEBUG(dbgs() << " Found cleanup code in block "
+ << Action->getStartBlock()->getName() << "\n");
+ // FIXME: This cleanup might chain into another, and we need to discover
+ // that.
+ return;
} else {
// Here we handle the case where the cleanup handler map contains a
// value for this block but the value is a nullptr. This means that
// would terminate the search for cleanup code, so the unconditional
// branch is the only case for which we might need to continue
// searching.
- if (BB == EndBB)
- return nullptr;
- BasicBlock *SuccBB;
- if (!match(BB->getTerminator(), m_UnconditionalBr(SuccBB)))
- return nullptr;
+ BasicBlock *SuccBB = followSingleUnconditionalBranches(BB);
+ if (SuccBB == BB || SuccBB == EndBB)
+ return;
BB = SuccBB;
continue;
}
InsertValueInst *Insert1 = nullptr;
InsertValueInst *Insert2 = nullptr;
Value *ResumeVal = Resume->getOperand(0);
- // If there is only one landingpad, we may use the lpad directly with no
- // insertions.
- if (isa<LandingPadInst>(ResumeVal))
- return nullptr;
- if (!isa<PHINode>(ResumeVal)) {
+ // If the resume value isn't a phi or landingpad value, it should be a
+ // series of insertions. Identify them so we can avoid them when scanning
+ // for cleanups.
+ if (!isa<PHINode>(ResumeVal) && !isa<LandingPadInst>(ResumeVal)) {
Insert2 = dyn_cast<InsertValueInst>(ResumeVal);
if (!Insert2)
- return createCleanupHandler(CleanupHandlerMap, BB);
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand());
if (!Insert1)
- return createCleanupHandler(CleanupHandlerMap, BB);
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
}
for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
II != IE; ++II) {
continue;
if (!Inst->hasOneUse() ||
(Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) {
- return createCleanupHandler(CleanupHandlerMap, BB);
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
}
}
- return nullptr;
+ return;
}
BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
// br i1 %matches, label %catch14, label %eh.resume
CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition());
if (!Compare || !Compare->isEquality())
- return createCleanupHandler(CleanupHandlerMap, BB);
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(),
- IE = BB->end();
- II != IE; ++II) {
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
+ for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+ II != IE; ++II) {
Instruction *Inst = II;
if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
continue;
continue;
if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
continue;
- return createCleanupHandler(CleanupHandlerMap, BB);
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
}
// The selector dispatch block should always terminate our search.
assert(BB == EndBB);
- return nullptr;
+ return;
+ }
+
+ if (isAsynchronousEHPersonality(Personality)) {
+ // If this is a landingpad block, split the block at the first non-landing
+ // pad instruction.
+ Instruction *MaybeCall = BB->getFirstNonPHIOrDbg();
+ if (LPadMap) {
+ while (MaybeCall != BB->getTerminator() &&
+ LPadMap->isLandingPadSpecificInst(MaybeCall))
+ MaybeCall = MaybeCall->getNextNode();
+ }
+
+ // Look for outlined finally calls.
+ if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) {
+ Function *Fin = FinallyCall.getCalledFunction();
+ assert(Fin && "outlined finally call should be direct");
+ auto *Action = new CleanupHandler(BB);
+ Action->setHandlerBlockOrFunc(Fin);
+ Actions.insertCleanupHandler(Action);
+ CleanupHandlerMap[BB] = Action;
+ DEBUG(dbgs() << " Found frontend-outlined finally call to "
+ << Fin->getName() << " in block "
+ << Action->getStartBlock()->getName() << "\n");
+
+ // Split the block if there were more interesting instructions and look
+ // for finally calls in the normal successor block.
+ BasicBlock *SuccBB = BB;
+ if (FinallyCall.getInstruction() != BB->getTerminator() &&
+ FinallyCall.getInstruction()->getNextNode() != BB->getTerminator()) {
+ SuccBB = BB->splitBasicBlock(FinallyCall.getInstruction()->getNextNode());
+ } else {
+ if (FinallyCall.isInvoke()) {
+ SuccBB = cast<InvokeInst>(FinallyCall.getInstruction())->getNormalDest();
+ } else {
+ SuccBB = BB->getUniqueSuccessor();
+ assert(SuccBB && "splitOutlinedFinallyCalls didn't insert a branch");
+ }
+ }
+ BB = SuccBB;
+ if (BB == EndBB)
+ return;
+ continue;
+ }
}
// Anything else is either a catch block or interesting cleanup code.
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(),
- IE = BB->end();
- II != IE; ++II) {
+ for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+ II != IE; ++II) {
Instruction *Inst = II;
if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
continue;
continue;
// If this is a catch block, there is no cleanup code to be found.
if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
- return nullptr;
+ return;
+ // If this a nested landing pad, it may contain an endcatch call.
+ if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
+ return;
// Anything else makes this interesting cleanup code.
- return createCleanupHandler(CleanupHandlerMap, BB);
+ return createCleanupHandler(Actions, CleanupHandlerMap, BB);
}
// Only unconditional branches in empty blocks should get this far.
assert(Branch && Branch->isUnconditional());
if (BB == EndBB)
- return nullptr;
+ return;
BB = Branch->getSuccessor(0);
}
- return nullptr;
+}
+
+// This is a public function, declared in WinEHFuncInfo.h and is also
+// referenced by WinEHNumbering in FunctionLoweringInfo.cpp.
+void llvm::parseEHActions(const IntrinsicInst *II,
+ SmallVectorImpl<ActionHandler *> &Actions) {
+ for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
+ uint64_t ActionKind =
+ cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
+ if (ActionKind == /*catch=*/1) {
+ auto *Selector = cast<Constant>(II->getArgOperand(I + 1));
+ ConstantInt *EHObjIndex = cast<ConstantInt>(II->getArgOperand(I + 2));
+ int64_t EHObjIndexVal = EHObjIndex->getSExtValue();
+ Constant *Handler = cast<Constant>(II->getArgOperand(I + 3));
+ I += 4;
+ auto *CH = new CatchHandler(/*BB=*/nullptr, Selector, /*NextBB=*/nullptr);
+ CH->setHandlerBlockOrFunc(Handler);
+ CH->setExceptionVarIndex(EHObjIndexVal);
+ Actions.push_back(CH);
+ } else if (ActionKind == 0) {
+ Constant *Handler = cast<Constant>(II->getArgOperand(I + 1));
+ I += 2;
+ auto *CH = new CleanupHandler(/*BB=*/nullptr);
+ CH->setHandlerBlockOrFunc(Handler);
+ Actions.push_back(CH);
+ } else {
+ llvm_unreachable("Expected either a catch or cleanup handler!");
+ }
+ }
+ std::reverse(Actions.begin(), Actions.end());
}
projects / oota-llvm.git / blobdiff