RFR: 8342607: Enhance register printing on x86_64 platforms [v3]

[Martin Doerr]

On Fri, 25 Oct 2024 10:16:45 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

>> Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Preserve offset in copied uc_mcontext in store_context.
>
> src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp line 551:
> 
>> 549:   st->cr();
>> 550:   st->cr();
>> 551:   for (int i = 0; i < 16; ++i) {
> 
> Better check if `fpregs` points into `*uc` before dereferencing it (asserting that it actually does).

An assertion is not ideal. We don't want to run into it while printing an hs_err file. I've added a sanity check and print another message instead if it's bad.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21615#discussion_r1816479415