Debugger: ScopeMirror has N^2 algorithm when building closure mirrors.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index c379ec9101a463ac36f25a334995395dcca2e7a6..7b13f05f89d251729e5b2e8f18695cb4fc0624ff 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -10766,34 +10766,6 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFrameDetails) {
 }
 
 
-// Copy all the context locals into an object used to materialize a scope.
-static bool CopyContextLocalsToScopeObject(
-    Isolate* isolate,
-    Handle<ScopeInfo> scope_info,
-    Handle<Context> context,
-    Handle<JSObject> scope_object) {
-  // Fill all context locals to the context extension.
-  for (int i = 0; i < scope_info->ContextLocalCount(); i++) {
-    VariableMode mode;
-    InitializationFlag init_flag;
-    int context_index = scope_info->ContextSlotIndex(
-        scope_info->ContextLocalName(i), &mode, &init_flag);
-
-    RETURN_IF_EMPTY_HANDLE_VALUE(
-        isolate,
-        SetProperty(isolate,
-                    scope_object,
-                    Handle<String>(scope_info->ContextLocalName(i)),
-                    Handle<Object>(context->get(context_index), isolate),
-                    NONE,
-                    kNonStrictMode),
-        false);
-  }
-
-  return true;
-}
-
-
 // Create a plain JSObject which materializes the local scope for the specified
 // frame.
 static Handle<JSObject> MaterializeLocalScopeWithFrameInspector(
@@ -10843,8 +10815,8 @@ static Handle<JSObject> MaterializeLocalScopeWithFrameInspector(
     // Third fill all context locals.
     Handle<Context> frame_context(Context::cast(frame->context()));
     Handle<Context> function_context(frame_context->declaration_context());
-    if (!CopyContextLocalsToScopeObject(
-            isolate, scope_info, function_context, local_scope)) {
+    if (!scope_info->CopyContextLocalsToScopeObject(
+            isolate, function_context, local_scope)) {
       return Handle<JSObject>();
     }
 
@@ -10996,8 +10968,8 @@ static Handle<JSObject> MaterializeClosure(Isolate* isolate,
       isolate->factory()->NewJSObject(isolate->object_function());
 
   // Fill all context locals to the context extension.
-  if (!CopyContextLocalsToScopeObject(
-          isolate, scope_info, context, closure_scope)) {
+  if (!scope_info->CopyContextLocalsToScopeObject(
+          isolate, context, closure_scope)) {
     return Handle<JSObject>();
   }
 
@@ -11116,8 +11088,8 @@ static Handle<JSObject> MaterializeBlockScope(
       isolate->factory()->NewJSObject(isolate->object_function());
 
   // Fill all context locals.
-  if (!CopyContextLocalsToScopeObject(
-          isolate, scope_info, context, block_scope)) {
+  if (!scope_info->CopyContextLocalsToScopeObject(
+          isolate, context, block_scope)) {
     return Handle<JSObject>();
   }
 
@@ -11139,8 +11111,8 @@ static Handle<JSObject> MaterializeModuleScope(
       isolate->factory()->NewJSObject(isolate->object_function());
 
   // Fill all context locals.
-  if (!CopyContextLocalsToScopeObject(
-          isolate, scope_info, context, module_scope)) {
+  if (!scope_info->CopyContextLocalsToScopeObject(
+          isolate, context, module_scope)) {
     return Handle<JSObject>();
   }