RFR: 8344355: Register corruption in MacroAssembler::lookup_secondary_supers_table_var: x86-64 only [v2]

[Vladimir Ivanov]

On Tue, 26 Nov 2024 11:04:16 GMT, Andrew Haley <aph at openjdk.org> wrote:

> but I'd advocate for clobbering registers only used on rare code paths to be a standard practice.

It would be nice to have an opt-in debugging feature to clobber registers (temporary or not used anymore). But that would require existing code to be annotated with such information.

BTW there's a similar case which is pervasive on x86: external address materialization requires an extra register when the address is not reachable in rip-relative addressing mode. There's `ForceUnreachable`, but it's turned off by default.

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

PR Comment: https://git.openjdk.org/jdk/pull/22365#issuecomment-2501782185