Reviewers: Toon Verwaest,
Message:
PTAL.
Description:
Optimize prototype chain when creating initial maps for functions used as
constructors
Please review this at https://codereview.chromium.org/332783002/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+50, -0 lines):
M src/objects.cc
A test/mjsunit/dictionary-properties.js
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index
bdfa23cde59d32626192b08ec182f5e2784550e6..a306e88b04716c9e96b229aa573f7d4b7cf4ae25
100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10189,6 +10189,10 @@ void
JSFunction::EnsureHasInitialMap(Handle<JSFunction> function) {
Handle<Object> prototype;
if (function->has_instance_prototype()) {
prototype = handle(function->instance_prototype(), isolate);
+ for (Handle<Object> p = prototype; !p->IsNull() && !p->IsJSProxy();
+ p = Object::GetPrototype(isolate, p)) {
+ JSObject::OptimizeAsPrototype(Handle<JSObject>::cast(p));
+ }
} else {
prototype = isolate->factory()->NewFunctionPrototype(function);
}
Index: test/mjsunit/dictionary-properties.js
diff --git a/test/mjsunit/dictionary-properties.js
b/test/mjsunit/dictionary-properties.js
new file mode 100644
index
0000000000000000000000000000000000000000..c70c598ac8cb617f7b0911a5964c1185c4f1b881
--- /dev/null
+++ b/test/mjsunit/dictionary-properties.js
@@ -0,0 +1,46 @@
+// 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.
+
+// Flags: --allow-natives-syntax
+
+// Test loading existent and nonexistent properties from dictionary
+// mode objects.
+
+function SlowObject() {
+ this.foo = 1;
+ this.bar = 2;
+ this.qux = 3;
+ delete this.qux;
+ assertFalse(%HasFastProperties(this));
+}
+function SlowObjectWithBaz() {
+ var o = new SlowObject();
+ o.baz = 4;
+ return o;
+}
+
+function Load(o) {
+ return o.baz;
+}
+
+for (var i = 0; i < 10; i++) {
+ var o1 = new SlowObject();
+ var o2 = SlowObjectWithBaz();
+ assertEquals(undefined, Load(o1));
+ assertEquals(4, Load(o2));
+}
+
+// Test objects getting optimized as fast prototypes.
+
+function SlowPrototype() {
+ this.foo = 1;
+}
+SlowPrototype.prototype.bar = 2;
+SlowPrototype.prototype.baz = 3;
+delete SlowPrototype.prototype.baz;
+
+assertFalse(%HasFastProperties(SlowPrototype.prototype));
+var fast_proto = new SlowPrototype();
+assertTrue(%HasFastProperties(SlowPrototype.prototype));
+assertTrue(%HasFastProperties(fast_proto.__proto__));
--
--
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