RFR: 8339113: AccessFlags can be u2 in metadata [v5]

[Martin Doerr]

On Thu, 19 Dec 2024 12:54:20 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 690:
>> 
>>> 688:     push(state);
>>> 689: 
>>> 690:     // Skip if we don't have to unlock. (???is this right???)
>> 
>> The logic seems consistent with other platforms. Not sure what you are querying.
>
> It wasn't the logic.  When I went through I didn't know if this instruction needed fixing because we loaded an unsigned short instead of an int.  So I left myself a note to look at it again that you noticed and I didn't in my final walk through.  It seems right but maybe someone with ppc knowledge can answer this.
> 
> 
>     rldicl_(R0, Raccess_flags, 64-JVM_ACC_SYNCHRONIZED_BIT, 63); // Extract bit and compare to 0.

The instruction looks still correct. We are checking the same bit of the 64 bit register as before. (Using `testbitdi` would also work.)

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PR Review Comment: https://git.openjdk.org/jdk/pull/22246#discussion_r1897420985