Bug 20862 - Inline code generation of eq_null/neq_null for CTI.
Summary: Inline code generation of eq_null/neq_null for CTI.
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: 528+ (Nightly build)
Hardware: Mac OS X 10.5
: P2 Normal
Assignee: Gavin Barraclough
Depends on:
Reported: 2008-09-15 15:29 PDT by Gavin Barraclough
Modified: 2008-09-15 16:33 PDT (History)
0 users

See Also:

The patch (12.31 KB, patch)
2008-09-15 15:31 PDT, Gavin Barraclough
ggaren: review+
Details | Formatted Diff | Diff

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Description Gavin Barraclough 2008-09-15 15:29:31 PDT
Inline code generation of eq_null/neq_null for CTI.  Uses vptr checking for StringObjectsThatAreMasqueradingAsBeingUndefined.  In the long run, the masquerading may be handled differently (through the StructureIDs - see bug #20823).

>1% on v8-tests.
Comment 1 Gavin Barraclough 2008-09-15 15:31:28 PDT
Created attachment 23448 [details]
The patch
Comment 2 Geoffrey Garen 2008-09-15 15:40:34 PDT
Comment on attachment 23448 [details]
The patch

r=me, but i give a stern parental was of the index finger at this vptr abuse -- we need to get off of it!

Also, please add a comment in JSObject.h by the declaration of JSObject::masqueradesAsUndefined that basically says, "You can't usefully override this virtual function without hand-coding some assembly in CTI.cpp"
Comment 3 Geoffrey Garen 2008-09-15 15:41:03 PDT

I said wag!
Comment 4 Gavin Barraclough 2008-09-15 16:33:52 PDT
Sending        JavaScriptCore/ChangeLog
Sending        JavaScriptCore/VM/CTI.cpp
Sending        JavaScriptCore/VM/CTI.h
Sending        JavaScriptCore/VM/Machine.cpp
Sending        JavaScriptCore/VM/Machine.h
Sending        JavaScriptCore/kjs/JSCell.h
Sending        JavaScriptCore/kjs/JSWrapperObject.h
Sending        JavaScriptCore/kjs/StringObject.h
Sending        JavaScriptCore/kjs/StringObjectThatMasqueradesAsUndefined.h
Transmitting file data .........
Committed revision 36462.