[WinEH] Update exception numbering to give handlers their own base state.

Differential Revision: http://reviews.llvm.org/D9512

llvm-svn: 237014

2 files changed, 87 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
index b89ca011648..72aa4214f9a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
@@ -299,6 +299,17 @@ void Win64Exception::emitCXXFrameHandler3Table(const MachineFunction *MF) {
 
   // The parent function and the catch handlers contribute to the 'ip2state'
   // table.
+
+  // Include ip2state entries for the beginning of the main function and
+  // for catch handler functions.
+  if (F == ParentF) {
+    FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1));
+    LastEHState = -1;
+  } else if (FuncInfo.HandlerBaseState.count(F)) {
+    FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, 
+                                     FuncInfo.HandlerBaseState[F]));
+    LastEHState = FuncInfo.HandlerBaseState[F];
+  }
   for (const auto &MBB : *MF) {
     for (const auto &MI : MBB) {
       if (!MI.isEHLabel()) {
@@ -323,7 +334,8 @@ void Win64Exception::emitCXXFrameHandler3Table(const MachineFunction *MF) {
       assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
              "Inconsistent landing pad map!");
 
-      if (SawPotentiallyThrowing) {
+      // FIXME: Should this be using FuncInfo.HandlerBaseState?
+      if (SawPotentiallyThrowing && LastEHState != -1) {
         FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1));
         SawPotentiallyThrowing = false;
         LastEHState = -1;
diff --git a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index fc5ca3ec586..3248ac71aa2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -82,16 +82,18 @@ static ISD::NodeType getPreferredExtendForValue(const Value *V) {
 
 namespace {
 struct WinEHNumbering {
-  WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo), NextState(0) {}
+  WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo),
+      CurrentBaseState(-1), NextState(0) {}
 
   WinEHFuncInfo &FuncInfo;
+  int CurrentBaseState;
   int NextState;
 
   SmallVector<ActionHandler *, 4> HandlerStack;
   SmallPtrSet<const Function *, 4> VisitedHandlers;
 
   int currentEHNumber() const {
-    return HandlerStack.empty() ? -1 : HandlerStack.back()->getEHState();
+    return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState();
   }
 
   void createUnwindMapEntry(int ToState, ActionHandler *AH);
@@ -401,17 +403,33 @@ static void print_name(const Value *V) {
 
 void WinEHNumbering::processCallSite(ArrayRef<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;
+    // Delete any actions that are already represented on the handler stack.
     delete Actions[FirstMismatch];
   }
 
-  bool EnteringScope = (int)Actions.size() > 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;
@@ -425,46 +443,75 @@ void WinEHNumbering::processCallSite(ArrayRef<ActionHandler *> Actions,
     HandlerStack.pop_back();
   }
 
-  // We need to create a new state number if we are exiting a try scope and we
-  // will not push any more actions.
   int TryHigh = NextState - 1;
-  if (!EnteringScope && !PoppedCatches.empty()) {
-    createUnwindMapEntry(currentEHNumber(), nullptr);
-    ++NextState;
-  }
-
   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 (int 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 (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc())) {
+      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);
+    }
     delete CH;
   }
 
+  // The handler functions may have pushed actions onto the handler stack
+  // that we expected to push here.  Compare the handler stack to our
+  // actions again to check for that possibility.
+  if (HandlerStack.size() > FirstMismatch) {
+    for (int E = std::min(HandlerStack.size(), Actions.size());
+         FirstMismatch < E; ++FirstMismatch) {
+      if (HandlerStack[FirstMismatch]->getHandlerBlockOrFunc() !=
+          Actions[FirstMismatch]->getHandlerBlockOrFunc())
+        break;
+      delete Actions[FirstMismatch];
+    }
+  }
+
+  DEBUG(dbgs() << "Pushing actions for CallSite: ");
+  print_name(CS ? CS.getCalledValue() : nullptr);
+  DEBUG(dbgs() << '\n');
+
   bool LastActionWasCatch = false;
   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]);
     // FIXME: Reenable this optimization!
     if (CurrActionIsCatch && LastActionWasCatch && false) {
+      DEBUG(dbgs() << "setEHState for handler to " << currentEHNumber()
+                   << "\n");
       Actions[I]->setEHState(currentEHNumber());
     } else {
+      DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() << ", ");
+      print_name(Actions[I]->getHandlerBlockOrFunc());
+      DEBUG(dbgs() << ")\n");
       createUnwindMapEntry(currentEHNumber(), Actions[I]);
+      DEBUG(dbgs() << "setEHState for handler to " << NextState << "\n");
       Actions[I]->setEHState(NextState);
       NextState++;
-      DEBUG(dbgs() << "Creating unwind map entry for: (");
-      print_name(Actions[I]->getHandlerBlockOrFunc());
-      DEBUG(dbgs() << ", " << currentEHNumber() << ")\n");
     }
     HandlerStack.push_back(Actions[I]);
     LastActionWasCatch = CurrActionIsCatch;
@@ -480,6 +527,11 @@ void WinEHNumbering::calculateStateNumbers(const Function &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];
+  }
+
   DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n');
   SmallVector<ActionHandler *, 4> ActionList;
   for (const BasicBlock &BB : F) {
@@ -498,12 +550,19 @@ void WinEHNumbering::calculateStateNumbers(const Function &F) {
       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');
   }
 
   FuncInfo.CatchHandlerMaxState[&F] = NextState - 1;
+
+  CurrentBaseState = OldBaseState;
 }
 
 /// clear - Clear out all the function-specific state. This returns this