[lworld] RFR: 8366743: [lworld]: Verifier adjustments for operations on 'uninitialized' [v3]

[Chen Liang]

On Thu, 11 Sep 2025 18:06:33 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> The updated spec places more restrictions on the use of uninitialized and uninitializedThis with certain bytecodes. Those spec changes are implemented with this patch and tested with a new set of tests. Verified with the new test as well as tiers 1-5.
>
> Matias Saavedra Silva has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Merge commit 'refs/pull/1566/head' of github.com:openjdk/valhalla into uninit_implementation_8366271
>  - Added fix and tests for old verifier

Since the ClassFile API doesn't support the old verifier, I won't add a corresponding case - however, it's interesting to find that the old verifier never supported uninitializedX items for if_acmpeq or if_acmpne, so this reduces the incompatibility risk even more.

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PR Comment: https://git.openjdk.org/valhalla/pull/1566#issuecomment-3282569516