[WinEH] Allow for multiple terminatepads

Fixes verifier errors with Windows EH and OpenMP, which injects a
terminate scope around parallel blocks.

Fixes PR35778

llvm-svn: 321676

3 files changed, 52 insertions, 14 deletions

diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 1ec084ff3f5..1978d2757ac 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -646,7 +646,7 @@ CodeGenFunction::getMSVCDispatchBlock(EHScopeStack::stable_iterator SI) {
     return DispatchBlock;
 
   if (EHS.getKind() == EHScope::Terminate)
-    DispatchBlock = getTerminateHandler();
+    DispatchBlock = getTerminateFunclet();
   else
     DispatchBlock = createBasicBlock();
   CGBuilderTy Builder(*this, DispatchBlock);
@@ -1334,24 +1334,15 @@ llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
   if (TerminateHandler)
     return TerminateHandler;
 
-  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
-
   // Set up the terminate handler.  This block is inserted at the very
   // end of the function by FinishFunction.
   TerminateHandler = createBasicBlock("terminate.handler");
+  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
   Builder.SetInsertPoint(TerminateHandler);
+
   llvm::Value *Exn = nullptr;
-  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
-      CurrentFuncletPad);
-  if (EHPersonality::get(*this).usesFuncletPads()) {
-    llvm::Value *ParentPad = CurrentFuncletPad;
-    if (!ParentPad)
-      ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
-    CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
-  } else {
-    if (getLangOpts().CPlusPlus)
-      Exn = getExceptionFromSlot();
-  }
+  if (getLangOpts().CPlusPlus)
+    Exn = getExceptionFromSlot();
   llvm::CallInst *terminateCall =
       CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
   terminateCall->setDoesNotReturn();
@@ -1363,6 +1354,42 @@ llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
   return TerminateHandler;
 }
 
+llvm::BasicBlock *CodeGenFunction::getTerminateFunclet() {
+  assert(EHPersonality::get(*this).usesFuncletPads() &&
+         "use getTerminateLandingPad for non-funclet EH");
+
+  llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
+  if (TerminateFunclet)
+    return TerminateFunclet;
+
+  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
+
+  // Set up the terminate handler.  This block is inserted at the very
+  // end of the function by FinishFunction.
+  TerminateFunclet = createBasicBlock("terminate.handler");
+  Builder.SetInsertPoint(TerminateFunclet);
+
+  // Create the cleanuppad using the current parent pad as its token. Use 'none'
+  // if this is a top-level terminate scope, which is the common case.
+  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
+      CurrentFuncletPad);
+  llvm::Value *ParentPad = CurrentFuncletPad;
+  if (!ParentPad)
+    ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
+  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
+
+  // Emit the __std_terminate call.
+  llvm::CallInst *terminateCall =
+      CGM.getCXXABI().emitTerminateForUnexpectedException(*this, nullptr);
+  terminateCall->setDoesNotReturn();
+  Builder.CreateUnreachable();
+
+  // Restore the saved insertion state.
+  Builder.restoreIP(SavedIP);
+
+  return TerminateFunclet;
+}
+
 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
   if (EHResumeBlock) return EHResumeBlock;
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 9dbd7cc3fcb..664b5107842 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -419,6 +419,9 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
   EmitIfUsed(*this, TerminateHandler);
   EmitIfUsed(*this, UnreachableBlock);
 
+  for (const auto &FuncletAndParent : TerminateFunclets)
+    EmitIfUsed(*this, FuncletAndParent.second);
+
   if (CGM.getCodeGenOpts().EmitDeclMetadata)
     EmitDeclMetadata();
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index a7c322d3b95..3e89586be3a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -34,6 +34,7 @@
 #include "clang/Frontend/CodeGenOptions.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/Support/Debug.h"
@@ -1420,6 +1421,9 @@ private:
   llvm::BasicBlock *TerminateHandler;
   llvm::BasicBlock *TrapBB;
 
+  /// Terminate funclets keyed by parent funclet pad.
+  llvm::MapVector<llvm::Value *, llvm::BasicBlock *> TerminateFunclets;
+
   /// True if we need emit the life-time markers.
   const bool ShouldEmitLifetimeMarkers;
 
@@ -1808,6 +1812,10 @@ public:
   /// getTerminateLandingPad - Return a landing pad that just calls terminate.
   llvm::BasicBlock *getTerminateLandingPad();
 
+  /// getTerminateLandingPad - Return a cleanup funclet that just calls
+  /// terminate.
+  llvm::BasicBlock *getTerminateFunclet();
+
   /// getTerminateHandler - Return a handler (not a landing pad, just
   /// a catch handler) that just calls terminate.  This is used when
   /// a terminate scope encloses a try.