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);
public:
WinEHFrameVariableMaterializer(Function *OutlinedFn,
FrameVarInfoMap &FrameVarInfo);
- ~WinEHFrameVariableMaterializer() {}
+ ~WinEHFrameVariableMaterializer() override {}
- virtual Value *materializeValueFor(Value *V) override;
+ Value *materializeValueFor(Value *V) override;
void escapeCatchObject(Value *V);
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) {
// 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());
++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,
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) {
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());
// 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) {
+ 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)
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(
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 nullptr;
+ 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) {
+
SmallVectorImpl<ActionHandler *> &Actions) {
for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
uint64_t ActionKind =
- cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
+ 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));
CH->setHandlerBlockOrFunc(Handler);
CH->setExceptionVarIndex(EHObjIndexVal);
Actions.push_back(CH);
- }
- else {
- assert(ActionKind == 0 && "expected a cleanup or a catch action!");
+ } 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());
}
-
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