Make VM::scratchBufferForSize thread safe

[Saam Barati]

We currently call it from many threads, but it's not thread safe ...

[Saam Barati]

Created attachment 318196 [details]
patch

[Build Bot]

Attachment 318196 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/runtime/VM.h:574:  The parameter name "size" adds no information, so it should be removed.  [readability/parameter_name] [5]
Total errors found: 1 in 3 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Geoffrey Garen]

Comment on attachment 318196 [details]
patch

r=me

[Mark Lam]

Comment on attachment 318196 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=318196&action=review

r=me with issues resolved.

> Source/JavaScriptCore/runtime/VM.cpp:1025
> +        ScratchBuffer* newBuffer = ScratchBuffer::create(m_sizeOfLastScratchBuffer);

Make sure that the newly allocated buffer's activeLength is set to 0.  I'm not sure it's an issue, but I'm thinking of GC scanning it incorrectly if the active length is not set.

[Saam Barati]

Comment on attachment 318196 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=318196&action=review

>> Source/JavaScriptCore/runtime/VM.cpp:1025
>> +        ScratchBuffer* newBuffer = ScratchBuffer::create(m_sizeOfLastScratchBuffer);
> 
> Make sure that the newly allocated buffer's activeLength is set to 0.  I'm not sure it's an issue, but I'm thinking of GC scanning it incorrectly if the active length is not set.

ScratchBuffer() already sets it to zero

[Saam Barati]

landed in:
https://trac.webkit.org/changeset/220777/webkit

[Radar WebKit Bug Importer]

<rdar://problem/33907882>