RFR: 8262328: Templatize JVMFlag boilerplate access methods [v2]

[David Holmes]

On Mon, 5 Apr 2021 17:42:49 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> We have a bunch of boilerplate method like:
>> 
>> JVMFlagAccess::boolAtPut (JVMFlag* f, bool* v, JVMFlagOrigin origin)
>> JVMFlagAccess::intAtPut (JVMFlag* f, int* v, JVMFlagOrigin origin)
>> JVMFlagAccess::uintAtPut (JVMFlag* f, uint* v, JVMFlagOrigin origin)
>> ...
>> 
>> Similarly, we also have 8 different functions: JVMFlag::{set_bool, set_int, set_intx, ...}
>> 
>> We should replace such patterns with
>> 
>> template <typename T>
>> JVMFlagAccess::set(JVMFlag* f, T* value, JVMFlagOrigin origin)
>> 
>> This would allow us to templatize the 8x boilerplate functions in writeableFlags.cpp.
>> 
>> The flag access code in whitebox.cpp can also be improved.
>
> Ioi Lam has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - removed unnecessary #include
>  - Restored <JVM_FLAG_TYPE(type)> in templates so we can require exact types (i.e., cannot mix size_t and uintx even they might be the same type of some platforms)

Hi Ioi,

In terms of readability and writeability I prefer <type>AtPut() over set<JVM_FLAG_TYPE(type)>(). Is there any way to push the JVM_FLAG_TYPE down a level so it doesn't shout at you when reading the code? set<type>() would look much much better.

Thanks,
David

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PR: https://git.openjdk.java.net/jdk/pull/3318