Speedup JSReceiver::GetKeys

src/runtime/runtime-object.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 978 matching lines @@
 
   Handle<FixedArray> contents;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, contents, JSReceiver::GetKeys(object, JSReceiver::OWN_ONLY));
 
   // Some fast paths through GetKeysInFixedArrayFor reuse a cached
   // property array and since the result is mutable we have to create
   // a fresh clone on each invocation.
   int length = contents->length();
   Handle<FixedArray> copy = isolate->factory()->NewFixedArray(length);
-  for (int i = 0; i < length; i++) {
-    Object* entry = contents->get(i);
-    if (entry->IsString()) {
-      copy->set(i, entry);
-    } else {
-      DCHECK(entry->IsNumber());
-      HandleScope scope(isolate);
-      Handle<Object> entry_handle(entry, isolate);
-      Handle<Object> entry_str =
-          isolate->factory()->NumberToString(entry_handle);
-      copy->set(i, *entry_str);
+  int offset = 0;
+  // Use an outer loop to avoid creating too many handles in the current
+  // handle scope.
+  while (offset < length) {
+    HandleScope scope(isolate);
+    offset += 100;
+    int end = Min(offset, length);
+    for (int i = offset - 100; i < end; i++) {
+      Object* entry = contents->get(i);
+      if (entry->IsString()) {
+        copy->set(i, entry);
+      } else {
+        DCHECK(entry->IsNumber());
+        Handle<Object> entry_handle(entry, isolate);
+        Handle<Object> entry_str =
+            isolate->factory()->NumberToString(entry_handle);
+        copy->set(i, *entry_str);
+      }
     }
   }
   return *isolate->factory()->NewJSArrayWithElements(copy);
 }
 
 
 RUNTIME_FUNCTION(Runtime_ToFastProperties) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
@@ skipping 538 matching lines @@
 RUNTIME_FUNCTION(Runtime_CreateIterResultObject) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, done, 1);
   return *isolate->factory()->NewJSIteratorResult(value, done);
 }
 
 }  // namespace internal
 }  // namespace v8