RFR: 8266368: Inaccurate after_unwind hook in C2 exception handler

[Dean Long]

On Tue, 16 Nov 2021 08:42:32 GMT, Erik Österlund <eosterlund at openjdk.org> wrote:

> When we throw an exception and unwind into a frame, the exception handler of that frame needs to call an after_unwind hook for the StackWatermark code, to support for concurrent stack processing. Unfortunately, for C2 frames, I inaccurately do this in OptoRuntime::rethrow_C, but the exception handler when unwinding into a C2 frame really is OptoRuntime::handle_exception_C.
> The handle_exception_C code does walk frames to the caller though, which also pokes the StackWatermark code. So in the end, there is no real bug here, but it works for the wrong reasons. So I'd like to move the hook in rethrow_C to handle_exception_C.

Looks good!

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

Marked as reviewed by dlong (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6405