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

serguei.spitsyn at oracle.com serguei.spitsyn at oracle.com
Tue Oct 16 18:34:39 UTC 2018

Re-sending my RFR. Behive managed not to deliver it to the target mailing lists. David got it because he was on the cc-list.

Please, review a fix for: https://bugs.openjdk.java.net/browse/JDK-8024368

Webrev: http://cr.openjdk.java.net/~sspitsyn/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

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