[lworld] RFR: 8378273: [lworld] Use acmp map to detect oops for VarHandle [v2]

[Chen Liang]

On Fri, 20 Feb 2026 11:22:35 GMT, Paul Hübner <phubner at openjdk.org> wrote:

>> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   interface-typed fields were using atomic flat VHs ???
>
> src/java.base/share/classes/jdk/internal/value/ValueClass.java line 62:
> 
>> 60:         // non-concrete value class always a pointer
>> 61:         if (!ValueClass.isConcreteValueClass(c))
>> 62:             return !c.isPrimitive();
> 
> What about primitive arrays?

A field of an array type can be never a flat value.

> test/jdk/valhalla/valuetypes/ValueClassCompatibilityTest.java line 106:
> 
>> 104:         hasOopsCase(true, String.class, "final identity class");
>> 105:         hasOopsCase(true, Comparable.class, "interface");
>> 106:         hasOopsCase(true, int[].class, "array class");
> 
> I'm not following. How does/can a primitive `int[]` contain oops?

A field `int[] a` is a reference, never flat.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/2143#discussion_r2833095184
PR Review Comment: https://git.openjdk.org/valhalla/pull/2143#discussion_r2833092267