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

[Hamlin Li]

On Wed, 1 Oct 2025 07:37:58 GMT, Fei Yang <fyang at openjdk.org> wrote:

> > * 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`.

OK, I'll keep the pretty string as lower cases.

> 
> > * 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?

Yes, it's printed out by `log_debug(os, cpu)`, e.g.

[0.070s][debug][os,cpu] Enabled RV64 feature "VendorId" (1743)
[0.070s][debug][os,cpu] Enabled RV64 feature "ArchId" (0)
[0.070s][debug][os,cpu] Enabled RV64 feature "ImpId" (0)
[0.070s][debug][os,cpu] Enabled RV64 feature "SATP" (48)
[0.070s][debug][os,cpu] Enabled RV64 feature "UnalignedScalar" (3)
[0.070s][debug][os,cpu] Enabled RV64 feature "ZicbozBlockSize" (64)

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PR Comment: https://git.openjdk.org/jdk/pull/27562#issuecomment-3355294857