Changeset 183935 in webkit for trunk/Source/JavaScriptCore/runtime/JSObject.h

Timestamp:

May 7, 2015, 11:01:46 AM (10 years ago)

Author:

[email protected]

Message:

Don't branch when accessing the callee
​https://bugs.webkit.org/show_bug.cgi?id=144645

Reviewed by Michael Saboff.

The branch was added in <​http://trac.webkit.org/changeset/81040> without
explanation.

kling found it to be a performance problem. See <​https://webkit.org/b/144586>.

Our theory of access to Registers is that it's up to the client to access
them in the right way. So, let's do that.

• interpreter/CallFrame.h:

(JSC::ExecState::callee):
(JSC::ExecState::setCallee): Call the field object instead of function
because nothing guarantees that it's a function.

• interpreter/ProtoCallFrame.h:

(JSC::ProtoCallFrame::callee):
(JSC::ProtoCallFrame::setCallee):

• interpreter/Register.h:
• runtime/JSObject.h:

(JSC::Register::object): Just do a cast like our other accessors do.
(JSC::Register::operator=):
(JSC::Register::function): Deleted.
(JSC::Register::withCallee): Deleted.

File:

• trunk/Source/JavaScriptCore/runtime/JSObject.h (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/JSObject.h

@@ -1453 +1453 @@
 }
 
-ALWAYS_INLINE JSObject* Register::function() const
-{
-    if (!jsValue())
-        return 0;
+ALWAYS_INLINE JSObject* Register::object() const
+{
     return asObject(jsValue());
 }
 
-ALWAYS_INLINE Register Register::withCallee(JSObject* callee)
-{
-    Register r;
-    r = JSValue(callee);
-    return r;
+ALWAYS_INLINE Register& Register::operator=(JSObject* object)
+{
+    u.value = JSValue::encode(JSValue(object));
+    return *this;
 }