Bug 64903

Summary:

DFG speculative JIT sometimes claims to use compare operands twice, leading to use count corruption

Product:

WebKit

Reporter:

Filip Pizlo <fpizlo>

Component:

JavaScriptCore

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

barraclough, fpizlo, webkit.review.bot

Priority:

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Attachments:

Description	Flags
the patch	none

Description Filip Pizlo 2011-07-20 16:40:54 PDT

The DFG speculative JIT's compare() helper method may call the JITCodeGenerator's non-speculative compare helper, which calls use() on the operands.  But then SpeculativeJIT::compare() also calls use() on the operands.  The SpeculativeJIT::compare() method should not call use() on the operands if the JITCodeGenerator has already done so.

Comment 1 Filip Pizlo 2011-07-20 16:45:11 PDT

Created attachment 101526 [details]
the patch

Comment 2 WebKit Review Bot 2011-07-20 17:24:13 PDT

Comment on attachment 101526 [details]
the patch

Clearing flags on attachment: 101526

Committed r91428: <http://trac.webkit.org/changeset/91428>

Comment 3 WebKit Review Bot 2011-07-20 17:24:17 PDT

All reviewed patches have been landed.  Closing bug.