Attachment 346181 Details for Bug 188201 – Patch

[patch] Patch

bug-188201-20180801031940.patch (text/plain), 2.20 KB, created by Yusuke Suzuki on 2018-07-31 11:19:41 PDT

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Creator: Yusuke Suzuki

Created: 2018-07-31 11:19:41 PDT

Size: 2.20 KB

patch

obsolete

>Subversion Revision: 234428
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index f552042e6590b9db15ccbdf62094cf05a16026f8..5c1578a8d8f5c3cdb10dad3cbef7c7e99c9d9fa2 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,18 @@
>+2018-07-31  Yusuke Suzuki  <utatane.tea@gmail.com>
>+
>+        [JSC] Remove unnecessary cellLock() in JSObject's GC marking if IndexingType is contiguous
>+        https://bugs.webkit.org/show_bug.cgi?id=188201
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        We do not reuse the existing butterfly with Contiguous shape for new ArrayStorage butterfly.
>+        When converting the butterfly with Contiguous shape to ArrayStorage, we always allocate a
>+        new one. So this cellLock() is unnecessary for contiguous shape since contigous shaped butterfly
>+        never becomes broken state. This patch removes unnecessary locking.
>+
>+        * runtime/JSObject.cpp:
>+        (JSC::JSObject::visitButterflyImpl):
>+
> 2018-07-31  Guillaume Emont  <guijemont@igalia.com>
> 
>         [JSC] Remove gcc warnings for 32-bit platforms
>diff --git a/Source/JavaScriptCore/runtime/JSObject.cpp b/Source/JavaScriptCore/runtime/JSObject.cpp
>index f9ed6eabc0312892980fbc8fee90014782d4d129..36dadd6d1040ea6fc3c675cd463ea27133b08301 100644
>--- a/Source/JavaScriptCore/runtime/JSObject.cpp
>+++ b/Source/JavaScriptCore/runtime/JSObject.cpp
>@@ -395,12 +395,9 @@ ALWAYS_INLINE Structure* JSObject::visitButterflyImpl(SlotVisitor& visitor)
>     Dependency indexingModeDependency = Dependency::fence(indexingMode);
>     Locker<JSCellLock> locker(NoLockingNecessary);
>     switch (indexingMode) {
>-    case ALL_CONTIGUOUS_INDEXING_TYPES:
>     case ALL_ARRAY_STORAGE_INDEXING_TYPES:
>         // We need to hold this lock to protect against changes to the innards of the butterfly
>-        // that can happen when the butterfly is used for array storage. We conservatively
>-        // assume that a contiguous butterfly may transform into an array storage one, though
>-        // this is probably more conservative than necessary.
>+        // that can happen when the butterfly is used for array storage.
>         locker = holdLock(cellLock());
>         break;
>     default:

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keith_miller: review+

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