[Sablevm-developer] prepare_invoke and exception

[David <db...@cs...>]

Hello,

When testing my JIT with athrow I noticed this and I thought it would be
good to report it.

The PREPARE_INVOKE* special instruction both prepare the method and invok=
e it.
The REPLACE instruction is after the PREPARE_INVOKE*.  This means that if
the methods terminates abruptly due to an exception the REPLACE will not
get executed.

This will not lead to incorrect behaviour but if the method is always
throwing exception at a call site, the REPLACEment will never occur for
that call site.  If it is always throwing exception, the previous
statement applies to all call sites.

Since this is a rare case and exceptions are already inefficient it may
not be worth the effort to change.

(My JIT compiler was never compiling my test method for this reason since=
 I
didn't have a JIT entry point in that code.)

David

---

David B=E9langer
Graduate Student
School of Computer Science
McGill University
Office: MC226

Web page:   http://www.cs.mcgill.ca/~dbelan2/
Public key: http://www.cs.mcgill.ca/~dbelan2/public_key.txt