[WinEH] Start inserting state number stores for C++ EH
This moves all the state numbering code for C++ EH to WinEHPrepare so
that we can call it from the X86 state numbering IR pass that runs
before isel.
Now we just call the same state numbering machinery and insert a bunch
of stores. It also populates MachineModuleInfo with information about
the current function.
llvm-svn: 238514
diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index 7246e1c..c2b3d84 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -2480,3 +2480,377 @@
}
std::reverse(Actions.begin(), Actions.end());
}
+
+namespace {
+struct WinEHNumbering {
+ WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo),
+ CurrentBaseState(-1), NextState(0) {}
+
+ WinEHFuncInfo &FuncInfo;
+ int CurrentBaseState;
+ int NextState;
+
+ SmallVector<std::unique_ptr<ActionHandler>, 4> HandlerStack;
+ SmallPtrSet<const Function *, 4> VisitedHandlers;
+
+ int currentEHNumber() const {
+ return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState();
+ }
+
+ void createUnwindMapEntry(int ToState, ActionHandler *AH);
+ void createTryBlockMapEntry(int TryLow, int TryHigh,
+ ArrayRef<CatchHandler *> Handlers);
+ void processCallSite(MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
+ ImmutableCallSite CS);
+ void popUnmatchedActions(int FirstMismatch);
+ void calculateStateNumbers(const Function &F);
+ void findActionRootLPads(const Function &F);
+};
+}
+
+void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
+ WinEHUnwindMapEntry UME;
+ UME.ToState = ToState;
+ if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
+ UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc());
+ else
+ UME.Cleanup = nullptr;
+ FuncInfo.UnwindMap.push_back(UME);
+}
+
+void WinEHNumbering::createTryBlockMapEntry(int TryLow, int TryHigh,
+ ArrayRef<CatchHandler *> Handlers) {
+ // See if we already have an entry for this set of handlers.
+ // This is using iterators rather than a range-based for loop because
+ // if we find the entry we're looking for we'll need the iterator to erase it.
+ int NumHandlers = Handlers.size();
+ auto I = FuncInfo.TryBlockMap.begin();
+ auto E = FuncInfo.TryBlockMap.end();
+ for ( ; I != E; ++I) {
+ auto &Entry = *I;
+ if (Entry.HandlerArray.size() != (size_t)NumHandlers)
+ continue;
+ int N;
+ for (N = 0; N < NumHandlers; ++N) {
+ if (Entry.HandlerArray[N].Handler != Handlers[N]->getHandlerBlockOrFunc())
+ break; // breaks out of inner loop
+ }
+ // If all the handlers match, this is what we were looking for.
+ if (N == NumHandlers) {
+ break;
+ }
+ }
+
+ // If we found an existing entry for this set of handlers, extend the range
+ // but move the entry to the end of the map vector. The order of entries
+ // in the map is critical to the way that the runtime finds handlers.
+ // FIXME: Depending on what has happened with block ordering, this may
+ // incorrectly combine entries that should remain separate.
+ if (I != E) {
+ // Copy the existing entry.
+ WinEHTryBlockMapEntry Entry = *I;
+ Entry.TryLow = std::min(TryLow, Entry.TryLow);
+ Entry.TryHigh = std::max(TryHigh, Entry.TryHigh);
+ assert(Entry.TryLow <= Entry.TryHigh);
+ // Erase the old entry and add this one to the back.
+ FuncInfo.TryBlockMap.erase(I);
+ FuncInfo.TryBlockMap.push_back(Entry);
+ return;
+ }
+
+ // If we didn't find an entry, create a new one.
+ WinEHTryBlockMapEntry TBME;
+ TBME.TryLow = TryLow;
+ TBME.TryHigh = TryHigh;
+ assert(TBME.TryLow <= TBME.TryHigh);
+ for (CatchHandler *CH : Handlers) {
+ WinEHHandlerType HT;
+ if (CH->getSelector()->isNullValue()) {
+ HT.Adjectives = 0x40;
+ HT.TypeDescriptor = nullptr;
+ } else {
+ auto *GV = cast<GlobalVariable>(CH->getSelector()->stripPointerCasts());
+ // Selectors are always pointers to GlobalVariables with 'struct' type.
+ // The struct has two fields, adjectives and a type descriptor.
+ auto *CS = cast<ConstantStruct>(GV->getInitializer());
+ HT.Adjectives =
+ cast<ConstantInt>(CS->getAggregateElement(0U))->getZExtValue();
+ HT.TypeDescriptor =
+ cast<GlobalVariable>(CS->getAggregateElement(1)->stripPointerCasts());
+ }
+ HT.Handler = cast<Function>(CH->getHandlerBlockOrFunc());
+ HT.CatchObjRecoverIdx = CH->getExceptionVarIndex();
+ TBME.HandlerArray.push_back(HT);
+ }
+ FuncInfo.TryBlockMap.push_back(TBME);
+}
+
+static void print_name(const Value *V) {
+#ifndef NDEBUG
+ if (!V) {
+ DEBUG(dbgs() << "null");
+ return;
+ }
+
+ if (const auto *F = dyn_cast<Function>(V))
+ DEBUG(dbgs() << F->getName());
+ else
+ DEBUG(V->dump());
+#endif
+}
+
+void WinEHNumbering::processCallSite(
+ MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
+ ImmutableCallSite CS) {
+ DEBUG(dbgs() << "processCallSite (EH state = " << currentEHNumber()
+ << ") for: ");
+ print_name(CS ? CS.getCalledValue() : nullptr);
+ DEBUG(dbgs() << '\n');
+
+ DEBUG(dbgs() << "HandlerStack: \n");
+ for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
+ DEBUG(dbgs() << " ");
+ print_name(HandlerStack[I]->getHandlerBlockOrFunc());
+ DEBUG(dbgs() << '\n');
+ }
+ DEBUG(dbgs() << "Actions: \n");
+ for (int I = 0, E = Actions.size(); I < E; ++I) {
+ DEBUG(dbgs() << " ");
+ print_name(Actions[I]->getHandlerBlockOrFunc());
+ DEBUG(dbgs() << '\n');
+ }
+ int FirstMismatch = 0;
+ for (int E = std::min(HandlerStack.size(), Actions.size()); FirstMismatch < E;
+ ++FirstMismatch) {
+ if (HandlerStack[FirstMismatch]->getHandlerBlockOrFunc() !=
+ Actions[FirstMismatch]->getHandlerBlockOrFunc())
+ break;
+ }
+
+ // Remove unmatched actions from the stack and process their EH states.
+ popUnmatchedActions(FirstMismatch);
+
+ DEBUG(dbgs() << "Pushing actions for CallSite: ");
+ print_name(CS ? CS.getCalledValue() : nullptr);
+ DEBUG(dbgs() << '\n');
+
+ bool LastActionWasCatch = false;
+ const LandingPadInst *LastRootLPad = nullptr;
+ for (size_t I = FirstMismatch; I != Actions.size(); ++I) {
+ // We can reuse eh states when pushing two catches for the same invoke.
+ bool CurrActionIsCatch = isa<CatchHandler>(Actions[I].get());
+ auto *Handler = cast<Function>(Actions[I]->getHandlerBlockOrFunc());
+ // Various conditions can lead to a handler being popped from the
+ // stack and re-pushed later. That shouldn't create a new state.
+ // FIXME: Can code optimization lead to re-used handlers?
+ if (FuncInfo.HandlerEnclosedState.count(Handler)) {
+ // If we already assigned the state enclosed by this handler re-use it.
+ Actions[I]->setEHState(FuncInfo.HandlerEnclosedState[Handler]);
+ continue;
+ }
+ const LandingPadInst* RootLPad = FuncInfo.RootLPad[Handler];
+ if (CurrActionIsCatch && LastActionWasCatch && RootLPad == LastRootLPad) {
+ DEBUG(dbgs() << "setEHState for handler to " << currentEHNumber() << "\n");
+ Actions[I]->setEHState(currentEHNumber());
+ } else {
+ DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() << ", ");
+ print_name(Actions[I]->getHandlerBlockOrFunc());
+ DEBUG(dbgs() << ") with EH state " << NextState << "\n");
+ createUnwindMapEntry(currentEHNumber(), Actions[I].get());
+ DEBUG(dbgs() << "setEHState for handler to " << NextState << "\n");
+ Actions[I]->setEHState(NextState);
+ NextState++;
+ }
+ HandlerStack.push_back(std::move(Actions[I]));
+ LastActionWasCatch = CurrActionIsCatch;
+ LastRootLPad = RootLPad;
+ }
+
+ // This is used to defer numbering states for a handler until after the
+ // last time it appears in an invoke action list.
+ if (CS.isInvoke()) {
+ for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
+ auto *Handler = cast<Function>(HandlerStack[I]->getHandlerBlockOrFunc());
+ if (FuncInfo.LastInvoke[Handler] != cast<InvokeInst>(CS.getInstruction()))
+ continue;
+ FuncInfo.LastInvokeVisited[Handler] = true;
+ DEBUG(dbgs() << "Last invoke of ");
+ print_name(Handler);
+ DEBUG(dbgs() << " has been visited.\n");
+ }
+ }
+
+ DEBUG(dbgs() << "In EHState " << currentEHNumber() << " for CallSite: ");
+ print_name(CS ? CS.getCalledValue() : nullptr);
+ DEBUG(dbgs() << '\n');
+}
+
+void WinEHNumbering::popUnmatchedActions(int FirstMismatch) {
+ // Don't recurse while we are looping over the handler stack. Instead, defer
+ // the numbering of the catch handlers until we are done popping.
+ SmallVector<CatchHandler *, 4> PoppedCatches;
+ for (int I = HandlerStack.size() - 1; I >= FirstMismatch; --I) {
+ std::unique_ptr<ActionHandler> Handler = HandlerStack.pop_back_val();
+ if (isa<CatchHandler>(Handler.get()))
+ PoppedCatches.push_back(cast<CatchHandler>(Handler.release()));
+ }
+
+ int TryHigh = NextState - 1;
+ int LastTryLowIdx = 0;
+ for (int I = 0, E = PoppedCatches.size(); I != E; ++I) {
+ CatchHandler *CH = PoppedCatches[I];
+ DEBUG(dbgs() << "Popped handler with state " << CH->getEHState() << "\n");
+ if (I + 1 == E || CH->getEHState() != PoppedCatches[I + 1]->getEHState()) {
+ int TryLow = CH->getEHState();
+ auto Handlers =
+ makeArrayRef(&PoppedCatches[LastTryLowIdx], I - LastTryLowIdx + 1);
+ DEBUG(dbgs() << "createTryBlockMapEntry(" << TryLow << ", " << TryHigh);
+ for (size_t J = 0; J < Handlers.size(); ++J) {
+ DEBUG(dbgs() << ", ");
+ print_name(Handlers[J]->getHandlerBlockOrFunc());
+ }
+ DEBUG(dbgs() << ")\n");
+ createTryBlockMapEntry(TryLow, TryHigh, Handlers);
+ LastTryLowIdx = I + 1;
+ }
+ }
+
+ for (CatchHandler *CH : PoppedCatches) {
+ if (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc())) {
+ if (FuncInfo.LastInvokeVisited[F]) {
+ DEBUG(dbgs() << "Assigning base state " << NextState << " to ");
+ print_name(F);
+ DEBUG(dbgs() << '\n');
+ FuncInfo.HandlerBaseState[F] = NextState;
+ DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber()
+ << ", null)\n");
+ createUnwindMapEntry(currentEHNumber(), nullptr);
+ ++NextState;
+ calculateStateNumbers(*F);
+ }
+ else {
+ DEBUG(dbgs() << "Deferring handling of ");
+ print_name(F);
+ DEBUG(dbgs() << " until last invoke visited.\n");
+ }
+ }
+ delete CH;
+ }
+}
+
+void WinEHNumbering::calculateStateNumbers(const Function &F) {
+ auto I = VisitedHandlers.insert(&F);
+ if (!I.second)
+ return; // We've already visited this handler, don't renumber it.
+
+ int OldBaseState = CurrentBaseState;
+ if (FuncInfo.HandlerBaseState.count(&F)) {
+ CurrentBaseState = FuncInfo.HandlerBaseState[&F];
+ }
+
+ size_t SavedHandlerStackSize = HandlerStack.size();
+
+ DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n');
+ SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
+ for (const BasicBlock &BB : F) {
+ for (const Instruction &I : BB) {
+ const auto *CI = dyn_cast<CallInst>(&I);
+ if (!CI || CI->doesNotThrow())
+ continue;
+ processCallSite(None, CI);
+ }
+ const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
+ if (!II)
+ continue;
+ const LandingPadInst *LPI = II->getLandingPadInst();
+ auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
+ if (!ActionsCall)
+ continue;
+ assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
+ parseEHActions(ActionsCall, ActionList);
+ if (ActionList.empty())
+ continue;
+ processCallSite(ActionList, II);
+ ActionList.clear();
+ FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
+ DEBUG(dbgs() << "Assigning state " << currentEHNumber()
+ << " to landing pad at " << LPI->getParent()->getName()
+ << '\n');
+ }
+
+ // Pop any actions that were pushed on the stack for this function.
+ popUnmatchedActions(SavedHandlerStackSize);
+
+ DEBUG(dbgs() << "Assigning max state " << NextState - 1
+ << " to " << F.getName() << '\n');
+ FuncInfo.CatchHandlerMaxState[&F] = NextState - 1;
+
+ CurrentBaseState = OldBaseState;
+}
+
+// This function follows the same basic traversal as calculateStateNumbers
+// but it is necessary to identify the root landing pad associated
+// with each action before we start assigning state numbers.
+void WinEHNumbering::findActionRootLPads(const Function &F) {
+ auto I = VisitedHandlers.insert(&F);
+ if (!I.second)
+ return; // We've already visited this handler, don't revisit it.
+
+ SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
+ for (const BasicBlock &BB : F) {
+ const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
+ if (!II)
+ continue;
+ const LandingPadInst *LPI = II->getLandingPadInst();
+ auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
+ if (!ActionsCall)
+ continue;
+
+ assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
+ parseEHActions(ActionsCall, ActionList);
+ if (ActionList.empty())
+ continue;
+ for (int I = 0, E = ActionList.size(); I < E; ++I) {
+ if (auto *Handler
+ = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc())) {
+ FuncInfo.LastInvoke[Handler] = II;
+ // Don't replace the root landing pad if we previously saw this
+ // handler in a different function.
+ if (FuncInfo.RootLPad.count(Handler) &&
+ FuncInfo.RootLPad[Handler]->getParent()->getParent() != &F)
+ continue;
+ DEBUG(dbgs() << "Setting root lpad for ");
+ print_name(Handler);
+ DEBUG(dbgs() << " to " << LPI->getParent()->getName() << '\n');
+ FuncInfo.RootLPad[Handler] = LPI;
+ }
+ }
+ // Walk the actions again and look for nested handlers. This has to
+ // happen after all of the actions have been processed in the current
+ // function.
+ for (int I = 0, E = ActionList.size(); I < E; ++I)
+ if (auto *Handler
+ = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc()))
+ findActionRootLPads(*Handler);
+ ActionList.clear();
+ }
+}
+
+void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn,
+ WinEHFuncInfo &FuncInfo) {
+ // Return if it's already been done.
+ if (!FuncInfo.LandingPadStateMap.empty())
+ return;
+
+ WinEHNumbering Num(FuncInfo);
+ Num.findActionRootLPads(*ParentFn);
+ // The VisitedHandlers list is used by both findActionRootLPads and
+ // calculateStateNumbers, but both functions need to visit all handlers.
+ Num.VisitedHandlers.clear();
+ Num.calculateStateNumbers(*ParentFn);
+ // Pop everything on the handler stack.
+ // It may be necessary to call this more than once because a handler can
+ // be pushed on the stack as a result of clearing the stack.
+ while (!Num.HandlerStack.empty())
+ Num.processCallSite(None, ImmutableCallSite());
+}
