RFR: 8310948: Fix ignored-qualifiers warning in Hotspot

[Daniel Jeliński]

On Mon, 3 Jul 2023 00:19:56 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Please review this attempt to fix ignored-qualifiers warning.
>> 
>> Example warnings:
>> 
>> src/hotspot/share/oops/method.hpp:413:19: warning: 'volatile' type qualifier on return type has no effect [-Wignored-qualifiers]
>>    CompiledMethod* volatile code() const;
>>                    ^~~~~~~~~
>> 
>> 
>> src/hotspot/share/jfr/periodic/jfrModuleEvent.cpp:65:20: warning: type qualifiers ignored on cast result type [-Wignored-qualifiers]
>>     65 |   event.set_source((const ModuleEntry* const)from_module);
>>        |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> 
>> 
>> The proposed fix removes the ignored qualifiers.
>> In a few AD files I replaced `const` with `constexpr` where I noticed that the method is returning a compile-time constant, and other platforms use `constexpr` on the same method.
>> 
>> Release, debug and slowdebug builds on Aarch64 / x64 and Mac / Linux complete without errors. Cross-compile GHA builds also pass.
>
> src/hotspot/cpu/aarch64/aarch64.ad line 2288:
> 
>> 2286: //=============================================================================
>> 2287: 
>> 2288: const bool Matcher::match_rule_supported(int opcode) {
> 
> Have to wonder if these were all meant to be `bool Match:xxx() const {`?

Yes, I think that may have been the original intent. I'll add const on these functions.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14674#discussion_r1250340625