RFR: 8368897: RISC-V: Cleanup RV_EXT_FEATURE_FLAGS & RV_NON_EXT_FEATURE_FLAGS [v2]

[Fei Yang]

On Tue, 30 Sep 2025 09:39:35 GMT, Hamlin Li <mli at openjdk.org> wrote:

> I'm also considering if we should remove the column ext_xx in RV_EXT_FEATURE_FLAGS, and the similar column in RV_NON_EXT_FEATURE_FLAGS in this pr, as it should be able to be generated from the pretty string. How do you think about it?
> 
> The different opinions could be:
> 
> * for RV_EXT_FEATURE_FLAGS, should we take for example `i` or `I` as pretty string?

The current `_features_string` on linux-riscv64 looks like:

rv64 rvi rvm rva rvf rvd rvc rvv zicboz zba zbb zbs zfa zfh zfhmin zvfh zicond


We append a `rv` prefix for `i`, `m`, `a`, `f`, `d`, `c` and `v`.

> * for RV_NON_EXT_FEATURE_FLAGS, should we use `mvendorid` or `VendorId` as pretty string?
>   let me know how do you think about it.

Seems not necessary to have a pretty string for non-extension flags. Is it used anywhere?

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PR Comment: https://git.openjdk.org/jdk/pull/27562#issuecomment-3355129759