RFR: 8344074: RISC-V: More accurate _exception_handler_size and _deopt_handler_size

[Hamlin Li]

On Wed, 13 Nov 2024 00:38:11 GMT, Fei Yang <fyang at openjdk.org> wrote:

> Hi, please review this small change.
> 
> I find that the reserved size for these two handlers are not accurate and are larger than needed. For `_exception_handler_size`, the used size is only 20 bytes for release build and about 60 bytes for debug build. Considering that the exception handler is not trivial, I reserved a little bit more than needed for release build (32 bytes). For `_deopt_handler_size`, `far_jump` will always emit two instructions.
> 
> Testing on linux-riscv64:
> - [x] tier1 (release)
> - [x] hotspot:tier1 (fastdebug)

Make sense to me. Thanks!

Just an unrelated question, how did you get the instructions size of `emit_exception_handler`?

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Marked as reviewed by mli (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/22053#pullrequestreview-2432717535
PR Comment: https://git.openjdk.org/jdk/pull/22053#issuecomment-2473226208