[Rev 01] RFR: 8238226: Revisit FunctionDescriptor

[Maurizio Cimadamore]

On Tue, 11 Feb 2020 16:40:29 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Continuation of: https://mail.openjdk.java.net/pipermail/panama-dev/2020-February/007418.html
>> 
>>> Hi,
>>> 
>>> Please review the following patch that revisits FunctionDescriptor: 1. 
>>> Adds appendArgumentLayouts, and changeReturnLayout combinator methods. 
>>> 2. Removes the variadic flag. This flag was not really being used in 
>>> practice, since we can not link variadic functions directly any ways. 
>>> Using the new appendArgumentLayouts method we can 'specialize' a base FD 
>>> with different argument layouts representing vararg arguments. I think 
>>> if a similar flag is needed in the future, we should consider adding 
>>> annotations to FunctionDescriptor, and making it an annotation instead, 
>>> but currently it doesn't seem like it's pulling it's weight by being in 
>>> the API.
>>> 
>>> Webrev: 
>>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/cleanup_fd/webrev.00/
>>> Bugs: https://bugs.openjdk.java.net/browse/JDK-8238226, 
>>> https://bugs.openjdk.java.net/browse/JDK-8237580
>>> 
>>> Again, this patch applies on top of the Binding cleanup patch.
>>> 
>>> Thanks,
>>> Jorn
> 
> The pull request has been updated with 1 additional commit.

Marked as reviewed by mcimadamore (Committer).

test/jdk/java/foreign/StdLibTest.java line 352:

> 351:             }
> 352:             FunctionDescriptor printfSpec = StdLibHelper.printfBase.appendArgumentLayouts(
> 353:                     args.stream().map(a -> a.layout).toArray(MemoryLayout[]::new));

I would have dealt with expanding the function descriptor in the same loop where we expand the method type - but what you have is also fine.

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PR: https://git.openjdk.java.net/panama-foreign/pull/15