RFR: 8309685: Fix -Wconversion warnings in assembler and register code

[Coleen Phillimore]

On Wed, 21 Jun 2023 12:38:17 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> This is essentially the same as PR https://github.com/openjdk/jdk/pull/14396 only without the asm/assembler.hpp changes for emit_int8, etc.  The casts and type changes here resolve header file -Wconversion warnings but not the 941 in assembler_x86.cpp.
>> Tested with tier 1-7, and tier1 on Oracle supported platforms.
>
> LGTM.

Thanks for reviewing and your attention @theRealAph.

> src/hotspot/cpu/x86/macroAssembler_x86.cpp line 2041:
> 
>> 2039:     emit_int8((uint8_t)0x65); // gs:
>> 2040:     emit_int8((uint8_t)0x90);
>> 2041:   }
> 
> Maybe there us a better way to do this with a template `emit_int8()` function, but maybe not now.

I fixed these casts as an alternative to the emit_int8 templates, so left them in this patch because they're more correct than what was there.  The emit_intXX functions need special treatment that I don't know how to fix right now.

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PR Comment: https://git.openjdk.org/jdk/pull/14584#issuecomment-1600799638
PR Review Comment: https://git.openjdk.org/jdk/pull/14584#discussion_r1236969081