[strong] class objects created in strong mode have their prototype frozen

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 99510e3abc8aa69cea2ab7d8d459072640fcea96..493c6365ab95aa13fda1371116bc9671c5bb21e8 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -1641,6 +1641,11 @@ void AstGraphBuilder::VisitClassLiteralContents(ClassLiteral* expr) {
   NewNode(op, environment()->Pop());  // prototype
   NewNode(op, environment()->Pop());  // literal
   if (is_strong(language_mode())) {
+    proto =
+        NewNode(javascript()->CallRuntime(Runtime::kObjectFreeze, 1), proto);
+    // Freezing the class prototype should never deopt.
+    PrepareFrameState(proto, BailoutId::None());
+
     // TODO(conradw): It would be more efficient to define the properties with

[rossberg, 2015/07/14 07:45:22]

Nit: move this comment before the proto freeze (applies there as well).
(Similarly in full-code backends)

[conradw, 2015/07/14 11:21:27]

Done.

     // the right attributes the first time round.
     literal =