[Webkit-unassigned] [Bug 19271] New: eliminate PIC branches by changing NaN handling in JSImmediate::toDouble

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Tue May 27 11:45:08 PDT 2008


http://bugs.webkit.org/show_bug.cgi?id=19271

           Summary: eliminate PIC branches by changing NaN handling in
                    JSImmediate::toDouble
           Product: WebKit
           Version: 526+ (Nightly build)
          Platform: Macintosh
        OS/Version: Mac OS X 10.5
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: darin at apple.com
                CC: mjs at apple.com, darin at apple.com, ggaren at apple.com,
                    oliver at apple.com


Many function have PIC branches only because they call one of the many
functions from JSValue that in turn call JSImmediate::toDouble, which gets NaN
for the undefined and null cases. Getting the NaN value involves access to a
global, and hence a PIC branch. Changing this to use a function, and one that's
not inlined, would make code inside JavaScriptCore faster on Mac OS X. It would
make code outside JavaScriptCore slower, because you'd still need a PIC branch
just to call the function.

Ideas?


-- 
Configure bugmail: http://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.



More information about the webkit-unassigned mailing list