1 files changed, 31 insertions, 2 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 441c54dc358..f5ba87f635d 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -11826,8 +11826,37 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
   QualType type = var->getType();
   if (type->isDependentType()) return;
 
-  if (var->hasAttr<BlocksAttr>())
-    getCurFunction()->addByrefBlockVar(var);
+  // __block variables might require us to capture a copy-initializer.
+  if (var->hasAttr<BlocksAttr>()) {
+    // It's currently invalid to ever have a __block variable with an
+    // array type; should we diagnose that here?
+
+    // Regardless, we don't want to ignore array nesting when
+    // constructing this copy.
+    if (type->isStructureOrClassType()) {
+      EnterExpressionEvaluationContext scope(
+          *this, ExpressionEvaluationContext::PotentiallyEvaluated);
+      SourceLocation poi = var->getLocation();
+      Expr *varRef =new (Context) DeclRefExpr(var, false, type, VK_LValue, poi);
+      ExprResult result
+        = PerformMoveOrCopyInitialization(
+            InitializedEntity::InitializeBlock(poi, type, false),
+            var, var->getType(), varRef, /*AllowNRVO=*/true);
+      if (!result.isInvalid()) {
+        result = MaybeCreateExprWithCleanups(result);
+        Expr *init = result.getAs<Expr>();
+        Context.setBlockVarCopyInit(var, init, canThrow(init));
+      }
+
+      // The destructor's exception spefication is needed when IRGen generates
+      // block copy/destroy functions. Resolve it here.
+      if (const CXXRecordDecl *RD = type->getAsCXXRecordDecl())
+        if (CXXDestructorDecl *DD = RD->getDestructor()) {
+          auto *FPT = DD->getType()->getAs<FunctionProtoType>();
+          FPT = ResolveExceptionSpec(poi, FPT);
+        }
+    }
+  }
 
   Expr *Init = var->getInit();
   bool IsGlobal = GlobalStorage && !var->isStaticLocal();