[foreign-abi] RFR: 8249803: Add LibraryLookup.Symbol

[Paul Sandoz]

On Tue, 21 Jul 2020 14:42:11 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> This patch adds the LibraryLookup.Symbol, which implements Addressable, and that is returned on a successful symbol
> lookup. This patch also tweaks VaList to also implement the Addressable interface (VaList already had an `address()`
> method).  The `ForeignLinker::downcallHandle` method has been tweaked to accept an Addressable as a function entry
> point. This allows downcall handle to target not only native symbols, but also upcall stubs (since upcall stubs are
> segments, which are addressable) as well as native memory addresses.  Some tests needed minor tweaks.

src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/LibraryLookup.java line 55:

> 54:      */
> 55:     interface Symbol extends Addressable {
> 56:         /**

Sealed and implementations are values?
It might even make sense as a value-based record, perhaps a little early to tell right now.

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

PR: https://git.openjdk.java.net/panama-foreign/pull/256