Integrated: 8199149: Improve the exception message thrown by VarHandle of unsupported operation

[Mandy Chung]

On Wed, 19 Jul 2023 00:12:53 GMT, Mandy Chung <mchung at openjdk.org> wrote:

> `VarForm::getMemberName` currently throws UOE with no information if the requested access mode is unsupported.   To provide the var handle information, move the access mode check to `VarHandle` so that the exception message can include the var handle information.  Changes include:
> 
> 1. change `VarHandle::checkAccessModeThenIsDirect` to check if the access mode is unsupported.  This check is only needed for direct var handle.
> 2. change `VarHandle::getMethodHandleUncached` to call `getMemberNameOrNull` and throw UOE with an informative exception message if the access mode is unsupported
> 
> The error message looks like:
> 
> java.lang.UnsupportedOperationException: compareAndSet is not supported for VarHandle[varType=java.lang.String, coord=[class Foo$Goo]]

This pull request has now been integrated.

Changeset: d7b94164
Author:    Mandy Chung <mchung at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/d7b941640638b35f9ac1ef11cd6bf6ccb795c29a
Stats:     12 lines in 4 files changed: 7 ins; 0 del; 5 mod

8199149: Improve the exception message thrown by VarHandle of unsupported operation

Reviewed-by: liach, jvernee

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PR: https://git.openjdk.org/jdk/pull/14928