[foreign-abi] RFR: 8248560: Specify the behaviour of the ForeignLinker returned by CSupport::getSystemLinker [v2]

[Jorn Vernee]

On Tue, 15 Sep 2020 16:56:20 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Added some initial API comments - impl comments to follow soon
>> 
>> Also checked implementation - the changes are trivial and look good.
>
> @mcimadamore & @PaulSandoz Thanks for the review, I've applied the suggested changes:
> https://github.com/openjdk/panama-foreign/pull/327/commits/24f77111f5817c22decbeef5bee91218784158e9
> I've also fixed a test that I noticed was no longer doing what is was supposed to (pre-existing to this PR).

> By "de facto" do you mean the default? If so how does one get a non-default one? Do we expect that a developer or
> third-party can implement this interface or is it only the jDK that provides the implementations? (i.e. ideally we
> would like to seal it.)

By 'de facto' I mean that there is no official single C ABI for a particular platform, but in _practice_ there is only
one. Maybe I'm being too pedantic here?

It is only intended for internal JDK classes to implement this Interface. Sealing might be an option, though I'm not
sure if the `permits` list of a sealed class counts as part of the specification, i.e. will adding or removing
implementations need a CSR? That might be prohibitive.

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PR: https://git.openjdk.java.net/panama-foreign/pull/327