RFR: 8264268: Don't use oop types for derived pointers [v2]

[Stefan Karlsson]

On Sun, 28 Mar 2021 12:00:03 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> I agree with jrose that having a type name for derived pointers would be better. But I wondered if it might be possible to make it stronger than just an alias type for intptr_t. I tried making it an enum class with a few supporting operations, and it doesn't look too bad.
> https://github.com/kimbarrett/openjdk-jdk/tree/derived_ptr

Sounds good. I've taken your patch and and did some minor cleanups.

> src/hotspot/share/compiler/oopMap.cpp line 290:
> 
>> 288:       intptr_t* derived_loc = (intptr_t*)fr->oopmapreg_to_location(omv.reg(),reg_map);
>> 289:       guarantee(derived_loc != NULL, "missing saved register");
>> 290:       oop *base_loc = fr->oopmapreg_to_oop_location(omv.content_reg(), reg_map);
> 
> `oop *base_loc` -> `oop* base_loc`

Done

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PR: https://git.openjdk.java.net/jdk/pull/3214