RFR: JDK-8163808 fix vtable assertion and logging for older classfiles

[Karen Kinnear]

Coleen,

Good catch - I will make that change.
Today this code is not called for arrays, but I totally appreciate you looking at the bigger picture
and preparing for potential other uses.


Here is the updated lines:
  KlassHandle vtklass_h = vt->klass();
  Klass* vtklass = vtklass_h();
  if (vtklass->is_instance_klass() &&
     (InstanceKlass::cast(vtklass)->major_version() >= klassVtable::VTABLE_TRANSITIVE_OVERRIDE_VERSION)) {
    assert(method() != NULL, "must have set method");
  }

Thanks!
Karen

> On Aug 12, 2016, at 10:47 AM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
> 
> 
> http://cr.openjdk.java.net/~acorn/8163808.hs/webrev/src/share/vm/oops/klassVtable.cpp.udiff.html
> 
> void vtableEntry::verify(klassVtable* vt, outputStream* st) {
>   NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
> + KlassHandle vtklass_h = vt->klass();
> + Klass* vtklass = vtklass_h();
> + if (InstanceKlass::cast(vtklass)->major_version() >= klassVtable::VTABLE_TRANSITIVE_OVERRIDE_VERSION) {
>   assert(method() != NULL, "must have set method");
> + }
> 
> I might be wrong but the vtable->klass() can be an ArrayKlass, so I think you have to do:
> 
> if (vtklass->oop_is_instance() && InstanceKlass::cast(vtklass) ...)
> 
> InstanceKlass::cast makes this assertion.  Otherwise, the code looks good.
> 
> Coleen
> 
> On 8/11/16 5:07 PM, Karen Kinnear wrote:
>> Please review:
>> https://bugs.openjdk.java.net/browse/JDK-8163808
>> 
>> http://cr.openjdk.java.net/~acorn/8163808.hs/webrev
>> 
>> Bug: For classfiles before class file version 51, JVMS did not support transitive over-ride behavior.
>> Implementation needed to check this in three places, not just one. Vtable size calculation is only exact
>> for later classfile versions.
>> 
>> Also fixed vtable logging output - since the method name-and-sig printing was changed to also print
>> the holder’s class name, we do not need to print the holder’s class name separately - it was printing twice.
>> 
>> Testing: linux-x64-slowdebug
>> rbt hs-nightly-runtime.js
>> jck vm,lang, api.java.lang
>> small invocation tests
>> 
>> thanks,
>> Karen
>