[WebAssembly] Add functions for EHScopes

Summary:
There are functions using the term 'funclet' to refer to both
1. an EH scopes, the structure of BBs that starts with
catchpad/cleanuppad and ends with catchret/cleanupret, and
2. a small function that gets outlined in AsmPrinter, which is the
original meaning of 'funclet'.

So far the two have been the same thing; EH scopes are always outlined
in AsmPrinter as funclets at the end of the compilation pipeline. But
now wasm also uses scope-based EH but does not outline those, so we now
need to correctly distinguish those two use cases in functions.

This patch splits `MachineBasicBlock::isFuncletEntry` into
`isFuncletEntry` and `isEHScopeEntry`, and
`MachineFunction::hasFunclets` into `hasFunclets` and `hasEHScopes`, in
order to distinguish the two different use cases. And this also changes
some uses of the term 'funclet' to 'scope' in `getFuncletMembership` and
change the function name to `getEHScopeMembership` because this function
is not about outlined funclets but about EH scope memberships.

This change is in the same vein as D45559.

Reviewers: majnemer, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D47005

llvm-svn: 333045

1 files changed, 9 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 277f48df783..118e26bcb24 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1379,7 +1379,10 @@ void SelectionDAGBuilder::visitCatchPad(const CatchPadInst &I) {
   auto Pers = classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
   bool IsMSVCCXX = Pers == EHPersonality::MSVC_CXX;
   bool IsCoreCLR = Pers == EHPersonality::CoreCLR;
+  bool IsSEH = isAsynchronousEHPersonality(Pers);
   MachineBasicBlock *CatchPadMBB = FuncInfo.MBB;
+  if (!IsSEH)
+    CatchPadMBB->setIsEHScopeEntry();
   // In MSVC C++ and CoreCLR, catchblocks are funclets and need prologues.
   if (IsMSVCCXX || IsCoreCLR)
     CatchPadMBB->setIsEHFuncletEntry();
@@ -1427,7 +1430,8 @@ void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
 
 void SelectionDAGBuilder::visitCleanupPad(const CleanupPadInst &CPI) {
   // Don't emit any special code for the cleanuppad instruction. It just marks
-  // the start of a funclet.
+  // the start of an EH scope/funclet.
+  FuncInfo.MBB->setIsEHScopeEntry();
   FuncInfo.MBB->setIsEHFuncletEntry();
   FuncInfo.MBB->setIsCleanupFuncletEntry();
 }
@@ -1449,6 +1453,7 @@ static void findUnwindDestinations(
     classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
   bool IsMSVCCXX = Personality == EHPersonality::MSVC_CXX;
   bool IsCoreCLR = Personality == EHPersonality::CoreCLR;
+  bool IsSEH = isAsynchronousEHPersonality(Personality);
 
   while (EHPadBB) {
     const Instruction *Pad = EHPadBB->getFirstNonPHI();
@@ -1461,6 +1466,7 @@ static void findUnwindDestinations(
       // Stop on cleanup pads. Cleanups are always funclet entries for all known
       // personalities.
       UnwindDests.emplace_back(FuncInfo.MBBMap[EHPadBB], Prob);
+      UnwindDests.back().first->setIsEHScopeEntry();
       UnwindDests.back().first->setIsEHFuncletEntry();
       break;
     } else if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(Pad)) {
@@ -1470,6 +1476,8 @@ static void findUnwindDestinations(
         // For MSVC++ and the CLR, catchblocks are funclets and need prologues.
         if (IsMSVCCXX || IsCoreCLR)
           UnwindDests.back().first->setIsEHFuncletEntry();
+        if (!IsSEH)
+          UnwindDests.back().first->setIsEHScopeEntry();
       }
       NewEHPadBB = CatchSwitch->getUnwindDest();
     } else {