RESOLVED FIXED 193513
[JSC] ToThis omission in DFGByteCodeParser is wrong 
https://bugs.webkit.org/show_bug.cgi?id=193513
Summary [JSC] ToThis omission in DFGByteCodeParser is wrong
Yusuke Suzuki
Reported 2019-01-16 15:38:25 PST
It assumes that `ToThis(ToThis(value)) === ToThis(value)`. But it is wrong since the semantics of ToThis in strict mode and ToThis in sloppy mode is different. If `ToThisFromSloppyMode(ToThisFromStrictMode(value))` is converted to `ToThisFromStrictMode(value)`, we have a bad time!
Attachments
Patch (7.34 KB, patch)
2019-01-16 19:58 PST, Yusuke Suzuki 		no flags
DetailsFormatted DiffDiff
Performance Numbers (7.48 KB, text/plain)
2019-01-16 21:07 PST, Yusuke Suzuki 		no flags
Details
Patch (7.45 KB, patch)
2019-01-16 21:11 PST, Yusuke Suzuki 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Yusuke Suzuki
Comment 1 2019-01-16 16:13:09 PST
This is not necessary. Original intent is already implemented in AI.
Yusuke Suzuki
Comment 2 2019-01-16 16:55:53 PST
Upload a patch after I ensured that the result is perf-neutral.
Yusuke Suzuki
Comment 3 2019-01-16 19:58:49 PST
Created attachment 359344 [details] Patch WIP
Yusuke Suzuki
Comment 4 2019-01-16 20:07:38 PST
<rdar://problem/45842236>
Yusuke Suzuki
Comment 5 2019-01-16 21:07:44 PST
Created attachment 359348 [details] Performance Numbers Performance looks neutral.
Yusuke Suzuki
Comment 6 2019-01-16 21:11:51 PST
Created attachment 359349 [details] Patch
WebKit Commit Bot
Comment 7 2019-01-17 00:10:59 PST
Comment on attachment 359349 [details] Patch Clearing flags on attachment: 359349 Committed r240106: <https://trac.webkit.org/changeset/240106>
WebKit Commit Bot
Comment 8 2019-01-17 00:11:01 PST
All reviewed patches have been landed. Closing bug.
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