[webkit-reviews] review denied: [Bug 30144] MIPS JIT Supports : [Attachment 42608] MIPS Patch Part 1 for YARR (new)

[bugzilla-daemon at webkit.org]

Gavin Barraclough <barraclough at apple.com> has denied Chao-ying Fu
<fu at mips.com>'s request for review:
Bug 30144: MIPS JIT Supports
https://bugs.webkit.org/show_bug.cgi?id=30144

Attachment 42608: MIPS Patch Part 1 for YARR (new)
https://bugs.webkit.org/attachment.cgi?id=42608&action=review

------- Additional Comments from Gavin Barraclough <barraclough at apple.com>
Hey Chao-ying,

Sorry for the delay, I'm going to r- this, let me explain why.

I'm guessing that you're assuming (quite reasonably) that YARR-JIT is an
extension to YARR, but this is not currently the case (although, slightly
confusingly, YARR_JIT does require YARR to be defined. :-/).  While both share
some common underpinnings, the two are currently used exclusively.  We hope to
use YARR to replace use of our port of PCRE on platforms for which we don't
have JIT support (an ever diminishing number, once MIPS joins the fold with JIT
support!) - however the YARR interpreter is currently a performance regression
versus PCRE.  YARR-JIT currently supports a subset of the JS-regex syntax, and
may need to fallback to use an interpreter to execute certain regular
expressions.  However due to PCRE having a higher performance we currently
fallback to PCRE rather than YARR (interpreter).

It is our intention both to complete YARR-JIT, so there is no fallback, and
also to improve the performance of YARR (interpreter), so that PCRE can be
fully deprecated.

For the time being, I suggest you skip over this step of enabling YARR without
the JIT, and go straight to enabling YARR-JIT.

cheers,
G.