Bug 68294

Summary:

method_check should repatch itself if it finds that the new structure(s) are the result of transitions from the old structure(s)

Product:

WebKit

Reporter:

Filip Pizlo <fpizlo>

Component:

JavaScriptCore

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

barraclough, fpizlo, ggaren, oliver, webkit.review.bot

Priority:

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Attachments:

Description	Flags
the patch	none
the patch	barraclough: review+

Filip Pizlo

Reported 2011-09-16 17:11:43 PDT

The method_check optimization in the old JIT is now relied upon as a kind of profiling by the DFG JIT. But this fails if the method_check takes the slow path simply because the structures it was caching on were transitioned. This results in missed dead code elimination and inlining opportunities in the DFG. The old JIT should simply repatch the fast path of method_check if it finds that the slow path was taken only because of structure transitions, but that the specific function optimization for that property is otherwise intact.

Attachments
the patch (9.20 KB, patch) 2011-09-16 17:15 PDT, Filip Pizlo	no flags	Details Formatted Diff Diff
the patch (9.40 KB, patch) 2011-09-16 17:34 PDT, Filip Pizlo	barraclough: review+	Details Formatted Diff Diff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.

Filip Pizlo

Comment 1 2011-09-16 17:15:46 PDT

Created attachment 107749 [details] the patch

WebKit Review Bot

Comment 2 2011-09-16 17:18:40 PDT

Attachment 107749 [details] did not pass style-queue: Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/JavaScriptCore/ChangeLog', u'Source..." exit_code: 1 Source/JavaScriptCore/jit/JITStubs.cpp:1634: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Source/JavaScriptCore/jit/JITStubs.cpp:1644: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Source/JavaScriptCore/jit/JITStubs.cpp:1645: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Source/JavaScriptCore/jit/JITStubs.cpp:1646: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Total errors found: 4 in 5 files If any of these errors are false positives, please file a bug against check-webkit-style.

Filip Pizlo

Comment 3 2011-09-16 17:34:33 PDT

Created attachment 107751 [details] the patch

Filip Pizlo

Comment 4 2011-09-17 16:32:41 PDT

Landed in r95388.

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