[foreign-memaccess+abi] Integrated: 8264386: LibraryLookup should be more friendly with implicit unloading

[Maurizio Cimadamore]

On Mon, 29 Mar 2021 15:36:13 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> Quoting from the PR:
> 
> Dereferencing a segment from a LibraryLookup is possible, in the following form:
> 
> LibraryLookup libLookup = ...
> MemorySegment segment = libLookup.lookup("foo").asSegmentRestricted(....)
> 
> The above code has a problem: there is no link between the produced segment and the original library lookup - meaning that, in principle, it's possible for the library to be unloaded when dereference occurs.
> 
> After having discussed many alternatives with Jorn, the best way to address this conundrum would be to add an overload of `LibraryLookup::lookup` which takes a lyout and returns a segment.
> 
> As part of this change I have also removed the LibraryLookup.Symbol API which seems unnecessary - now you can lookup an address or a segment. Of course, looking up a segment is creating a restricted segment (so it should be treated as unsafe).
> 
> I've added a test to make sure that the new API works as expected.

This pull request has now been integrated.

Changeset: d70c1e40
Author:    Maurizio Cimadamore <mcimadamore at openjdk.org>
URL:       https://git.openjdk.java.net/panama-foreign/commit/d70c1e40
Stats:     126 lines in 11 files changed: 48 ins; 30 del; 48 mod

8264386: LibraryLookup should be more friendly with implicit unloading

Reviewed-by: psandoz, jvernee

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PR: https://git.openjdk.java.net/panama-foreign/pull/480