RFR: 8310405: Linker.Option.firstVariadicArg should specify which index values are valid

[Jorn Vernee]

On Tue, 20 Jun 2023 22:59:42 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> src/java.base/share/classes/java/lang/foreign/Linker.java line 650:
>> 
>>> 648:          *          function descriptor associated with a downcall linkage request}
>>> 649:          * <p>
>>> 650:          * The {@code index} value must be greater than zero, and less than or equal to the number of argument layouts
>> 
>> Why > 0 and not >= 0? If the list of argument layout is empty, wouldn't the first vararg be in position 0? E.g. a call to a function `m(...)` with _no_ actual arguments?
>
> E.g. are we making an assumption here that if no arguments are passed, then the calling sequence won't be affected by variadic-ness - is that assumption always true?

Ah, sorry, this is just a  mistake I made. It should be >= 0

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PR Review Comment: https://git.openjdk.org/jdk/pull/14565#discussion_r1236015716