RFR: 8283737: riscv: MacroAssembler::stop() should emit fixed-length instruction sequence [v2]

[Xiaolin Zheng]

On Tue, 29 Mar 2022 08:32:28 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Xiaolin Zheng has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Polish comments as the suggestion
>
> src/hotspot/cpu/riscv/macroAssembler_riscv.cpp line 532:
> 
>> 530: 
>> 531: void MacroAssembler::stop(const char* msg) {
>> 532:   // these shall generate fixed-length instruction sequences
> 
> Looks reasonable to me. (Not a JDK Reviewer)
> Suggestion for the code comment:
> 
> @@ -531,6 +531,9 @@ void MacroAssembler::resolve_jobject(Register value, Register thread, Register t
>  void MacroAssembler::stop(const char* msg) {
>    address ip = pc();
>    pusha();
> +  // The length of the instruction sequence emitted should be independent
> +  // of the values of msg and ip so that size of mach node for scratch emit
> +  // and normal emit matches.
>    li(c_rarg0, (uintptr_t)(address)msg);
>    li(c_rarg1, (uintptr_t)(address)ip);
>    mv(c_rarg2, sp);

Thanks for reviewing this patch and the polish of comments, Felix. It looks more precise than before.

-------------

PR: https://git.openjdk.java.net/jdk/pull/7982