RFR(S): 8024368: private methods are allocated vtable slots

[Karen Kinnear]

Serguei,

Fix looks good. Officially reviewed.

Many thanks for the tests and the -Xlog output. Many thanks for fixing this.


thanks,
Karen

> On Oct 16, 2018, at 1:03 AM, serguei.spitsyn at oracle.com wrote:
> 
> Please, review a fix for:
>   https://bugs.openjdk.java.net/browse/JDK-8024368 <https://bugs.openjdk.java.net/browse/JDK-8024368>
> 
> Webrev:
>   http://cr.openjdk.java.net/~sspitsyn/webrevs/2018/8024368-priv-vtable.2/ <http://cr.openjdk.java.net/%7Esspitsyn/webrevs/2018/8024368-priv-vtable.2/>
> 
> 
> Summary:
> 
>   Private method should not allocate vtable indeces.
>   The fix tweaks several conditions in the functions:
>   klassVtable::update_inherited_vtable() and klassVtable::needs_new_vtable_entry(),
>   adds a couple of asserts and makes several comments up-to-date.
> 
>   The fix was preliminary reviewed by Karen, David H. and Lois.
> 
> Testing:
> 
>   The fix was verified with runtime/{appcds+Nestmates+RedefineTests+SelectionResolution}
>   and vmTestbase/vm/runtime/defmeth tests.
>   Also, I ran a mach5 job with the flags: tier1,tier2,hs-tier3,hs-tier4,hs-tier5.
> 
>   By suggestion from David, it was also tested with the -Xlog output for vtables before and after the fix.
>   I've done this comparison (awk was used to get rid of the first column with the time stamps). 
>   It shows that private methods were included into vtable before the fix but not included after.
>   Please, see one fragment as an example: 
> 
>    166c166 
>    <  copy vtable from java.lang.Object to java.lang.StackFrameInfo size 17 
>    --- 
>    >  copy vtable from java.lang.Object to java.lang.StackFrameInfo size 16 
>    180d179 
>    <  adding java.lang.StackFrameInfo.ensureRetainClassRefEnabled()V at index 16, flags: private 
>    182c181 
>    <  copy vtable from java.lang.StackFrameInfo to java.lang.LiveStackFrameInfo size 17 
>    --- 
>    >  copy vtable from java.lang.StackFrameInfo to java.lang.LiveStackFrameInfo size 16 
>    188,201c187,191 
>    <  copy vtable from java.lang.Object to java.lang.StackStreamFactory$AbstractStackWalker size 18 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.close()V at index 5, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.toStackWalkMode(Ljava/lang/StackWalker;I)I at index 6, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.consumeFrames()Ljava/lang/Object; at index 7, flags: protected abstract 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.initFrameBuffer()V at index 8, flags: protected abstract 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.batchSize(I)I at index 9, flags: protected abstract 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.getNextBatchSize()I at index 10, flags: protected 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.skipReflectionFrames()Z at index 11, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.doStackWalk(JIIII)Ljava/lang/Object; at index 12, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.getNextBatch()I at index 13, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.beginStackWalk()Ljava/lang/Object; at index 14, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(I)I at index 15, flags: private 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(JJII[Ljava/lang/Object;)I at index 16, flags: private native 
>    <  adding java.lang.StackStreamFactory$AbstractStackWalker.callStackWalk(JIII[Ljava/lang/Object;)Ljava/lang/Object; at index 17, flags: private native 
>    --- 
>    >  copy vtable from java.lang.Object to java.lang.StackStreamFactory$AbstractStackWalker size 9 
>    >  adding java.lang.StackStreamFactory$AbstractStackWalker.consumeFrames()Ljava/lang/Object; at index 5, flags: protected abstract 
>    >  adding java.lang.StackStreamFactory$AbstractStackWalker.initFrameBuffer()V at index 6, flags: protected abstract 
>    >  adding java.lang.StackStreamFactory$AbstractStackWalker.batchSize(I)I at index 7, flags: protected abstract 
>    >  adding java.lang.StackStreamFactory$AbstractStackWalker.getNextBatchSize()I at index 8, flags: protected 
> 
> 
> Thanks,
> Serguei
>