[lworld] RFR: 8274800: [lworld] Primitive classes can't be retransformed

[Serguei Spitsyn]

On Sat, 4 Dec 2021 00:30:11 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

> Fix for java.lang.instrument.Instrumentation.retransformClasses()
>
> Cases for retransformation primitive to identity (and identity to primitive) classes and changing primitive class fields (so default_value becomes invalid) are handled by existing code and spec changes are not required.
>
> Also added serviceability test to hotspot_valhalla group

Marked as reviewed by sspitsyn (no project role).

src/hotspot/share/prims/jvmtiClassFileReconstituter.cpp line 886:

> 884:
> 885:   // JVMSpec|           u2 access_flags;
> 886:   write_u2(ik()->access_flags().get_flags() & (JVM_RECOGNIZED_CLASS_MODIFIERS | JVM_ACC_INLINE));

Would it better to consider adding JVM_ACC_INLINE to JVM_RECOGNIZED_CLASS_MODIFIERS?
Also, I see other definitions of the JVM_RECOGNIZED_CLASS_MODIFIERS in files:

src/hotspot/share/include/jvm_constants.h
src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/ClassConstants.java

Do we want this modifier added there as well?

test/hotspot/jtreg/TEST.groups line 58:

> 56:   runtime/valhalla \
> 57:   compiler/valhalla \
> 58:   serviceability/jvmti/Valhalla

For consistency, should the we rename the test sub-folder from `Valhalla` to `valhalla` ?
This comment is not about this current fix though.

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PR: https://git.openjdk.java.net/valhalla/pull/588