Bug 203040

Summary: Disable pichdr generation on MIPS for return location labels
Product: WebKit Reporter: Paulo Matos <pmatos>
Component: New BugsAssignee: Paulo Matos <pmatos>
Status: RESOLVED FIXED    
Severity: Normal CC: commit-queue, ews-watchlist, guijemont, keith_miller, mark.lam, msaboff, saam, ticaiolima, tzagallo, webkit-bug-importer, ysuzuki
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 203290    
Bug Blocks:    
Attachments:
Description Flags
Patch
none
Patch none

Paulo Matos
Reported 2019-10-16 09:59:39 PDT
Disable pichdr generation on MIPS for return location labels
Attachments
Patch (1.85 KB, patch)
2019-10-16 10:02 PDT, Paulo Matos 		no flags
DetailsFormatted DiffDiff
Patch (2.02 KB, patch)
2019-10-24 00:14 PDT, Paulo Matos 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Paulo Matos
Comment 1 2019-10-16 10:02:42 PDT
Created attachment 381079 [details] Patch
Caio Lima
Comment 2 2019-10-16 22:38:41 PDT
Comment on attachment 381079 [details] Patch LGTM if bots are green. It seems that MIPS EWS is down.
Guillaume Emont
Comment 3 2019-10-22 02:25:57 PDT
Comment on attachment 381079 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=381079&action=review > Source/JavaScriptCore/offlineasm/mips.rb:686 > + # Only generate a pichdr if the label is not a return location - a cpload > + # (generated by pichdr) after this type of label would cause the a gp register > + # corruption. This regular expression needs to stay in sync with the labels > + # generated in macro defineOSRExitReturnLabel defined llint/LowLevelInterpreter.asm As far as I understand, the issue is when regular (non-OSR) execution gets through the OSR return label, but the cpload only sets gp correctly if t9 contains the address of the start of cpload, which is the case when we call into it (with "jr t9"), but not when we just execute through the label. I think a note explaining the above should be included in this comment to clarify the reasons for this check.
Paulo Matos
Comment 4 2019-10-24 00:14:46 PDT
Created attachment 381782 [details] Patch
WebKit Commit Bot
Comment 5 2019-10-24 01:36:07 PDT
Comment on attachment 381782 [details] Patch Clearing flags on attachment: 381782 Committed r251533: <https://trac.webkit.org/changeset/251533>
WebKit Commit Bot
Comment 6 2019-10-24 01:36:09 PDT
All reviewed patches have been landed. Closing bug.
Radar WebKit Bug Importer
Comment 7 2019-10-24 01:37:34 PDT
<rdar://problem/56571914>
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