RFR: 8317545: AIX PPC64: Implementation of Foreign Function & Memory API [v4]

[Jorn Vernee]

On Mon, 16 Oct 2023 16:20:49 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> The AIX linker has a few minor diffs to the linux ABIv1 linker. In addition, double values have only 4 Byte alignment within structures. This PR is based on JDK22 version of the FFI.
>
> Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert changes to PlatformLayouts.java

src/java.base/share/classes/jdk/internal/foreign/abi/ppc64/aix/AixPPC64Linker.java line 64:

> 62:         // Note: It is possible to enforce 8-byte alignment by #pragma align (natural)
> 63:         // Therefore, we use normal checks if we are already 8-byte aligned.
> 64:         if ((offset % 8 != 0) && (member instanceof ValueLayout vl && vl.carrier() == double.class)) {

I think you should check for the correct byte order as well at some point, for this special case

test/micro/org/openjdk/bench/java/lang/foreign/pointers/NativeType.java line 61:

> 59:         @Override
> 60:         public ValueLayout.OfInt layout() {
> 61:             return (ValueLayout.OfInt) LINKER.canonicalLayouts().get("int");

For this benchmark, we rely on constant folding through these layouts. So, we shouldn't go through `canonicalLayouts` here. We can store the layout in a `static final` field, and then return it here instead.

test/micro/org/openjdk/bench/java/lang/foreign/pointers/NativeType.java line 68:

> 66:         @Override
> 67:         public ValueLayout.OfDouble layout() {
> 68:             return (ValueLayout.OfDouble) LINKER.canonicalLayouts().get("double");

Same here

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PR Review Comment: https://git.openjdk.org/jdk/pull/16179#discussion_r1361340368
PR Review Comment: https://git.openjdk.org/jdk/pull/16179#discussion_r1361338651
PR Review Comment: https://git.openjdk.org/jdk/pull/16179#discussion_r1361338681