RFR: 8365047: Remove exception handler stub code in C2 [v2]

[Andrew Dinn]

On Thu, 28 Aug 2025 13:32:18 GMT, Ruben <duke at openjdk.org> wrote:

>> @ruben-arm BTW, what exactly do you mean by 'the main code'?
>
> @adinn By the "main code" I mean the region of an `nmethod` between the entry point and the `nmethod`'s stub code.

@ruben-arm Ok, so the problem you are describing is when the nmethod code section ends with a `br` that is not supposed to return. By accident `lr` is left pointing to the first instruction in the stubs section. Some code checks `lr` and decides we are doing a deopt even though this is really just some other type of call.

Where is the code that checks the address in lr? I'd like to understand what it is that the checking code dislikes just in case there is a wider problem here.

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PR Comment: https://git.openjdk.org/jdk/pull/26678#issuecomment-3234057765