1 files changed, 20 insertions, 18 deletions

diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 95e0030866..4cf7f12bd6 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -1127,14 +1127,6 @@ static void BeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *S) {
   CGF.EmitAutoVarCleanups(var);
 }
 
-namespace {
-  struct CallRethrow : EHScopeStack::Cleanup {
-    void Emit(CodeGenFunction &CGF, Flags flags) {
-      CGF.EmitCallOrInvoke(getReThrowFn(CGF));
-    }
-  };
-}
-
 /// Emit the structure of the dispatch block for the given catch scope.
 /// It is an invariant that the dispatch block already exists.
 static void emitCatchDispatchBlock(CodeGenFunction &CGF,
@@ -1246,11 +1238,12 @@ void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
   if (HaveInsertPoint())
     Builder.CreateBr(ContBB);
 
-  // Determine if we need an implicit rethrow for all these catch handlers.
-  bool ImplicitRethrow = false;
+  // Determine if we need an implicit rethrow for all these catch handlers;
+  // see the comment below.
+  bool doImplicitRethrow = false;
   if (IsFnTryBlock)
-    ImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
-                      isa<CXXConstructorDecl>(CurCodeDecl);
+    doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
+                        isa<CXXConstructorDecl>(CurCodeDecl);
 
   // Perversely, we emit the handlers backwards precisely because we
   // want them to appear in source order.  In all of these cases, the
@@ -1273,15 +1266,24 @@ void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
     // Initialize the catch variable and set up the cleanups.
     BeginCatch(*this, C);
 
-    // If there's an implicit rethrow, push a normal "cleanup" to call
-    // _cxa_rethrow.  This needs to happen before __cxa_end_catch is
-    // called, and so it is pushed after BeginCatch.
-    if (ImplicitRethrow)
-      EHStack.pushCleanup<CallRethrow>(NormalCleanup);
-
     // Perform the body of the catch.
     EmitStmt(C->getHandlerBlock());
 
+    // [except.handle]p11:
+    //   The currently handled exception is rethrown if control
+    //   reaches the end of a handler of the function-try-block of a
+    //   constructor or destructor.
+
+    // It is important that we only do this on fallthrough and not on
+    // return.  Note that it's illegal to put a return in a
+    // constructor function-try-block's catch handler (p14), so this
+    // really only applies to destructors.
+    if (doImplicitRethrow && HaveInsertPoint()) {
+      EmitCallOrInvoke(getReThrowFn(*this));
+      Builder.CreateUnreachable();
+      Builder.ClearInsertionPoint();
+    }
+
     // Fall out through the catch cleanups.
     CatchScope.ForceCleanup();