Integrated: 8312522: Implementation of Foreign Function & Memory API

[Jorn Vernee]

On Tue, 1 Aug 2023 10:29:06 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> This patch contains the implementation of the foreign linker & memory API JEP for Java 22. The initial patch is composed of commits brought over directly from the [panama-foreign repo](https://github.com/openjdk/panama-foreign). The main changes found in this patch come from the following PRs:
> 
> 1. https://github.com/openjdk/panama-foreign/pull/836 Where previous iterations supported converting Java strings to and from native strings in the UTF-8 encoding, we've extended the supported encoding to all the encodings found in the `java.nio.charset.StandardCharsets` class.
> 2. https://github.com/openjdk/panama-foreign/pull/838 We dropped the `MemoryLayout::sequenceLayout` factory method which inferred the size of the sequence to be `Long.MAX_VALUE`, as this led to confusion among clients. A client is now required to explicitly specify the sequence size.
> 3. https://github.com/openjdk/panama-foreign/pull/839 A new API was added: `Linker::canonicalLayouts`, which exposes a map containing the platform-specific mappings of common C type names to memory layouts.
> 4. https://github.com/openjdk/panama-foreign/pull/840 Memory access varhandles, as well as byte offset and slice handles derived from memory layouts, now feature an additional 'base offset' coordinate that is added to the offset computed by the handle. This allows composing these handles with other offset computation strategies that may not be based on the same memory layout. This addresses use-cases where clients are working with 'dynamic' layouts, whose size might not be known statically, such as variable length arrays, or variable size matrices.
> 5. https://github.com/openjdk/panama-foreign/pull/841 Remove this now redundant API. Clients can simply use the difference between the base address of two memory segments.
> 6. https://github.com/openjdk/panama-foreign/pull/845 Disambiguate uses of `SegmentAllocator::allocateArray`, by renaming methods that both allocate + initialize memory segments to `allocateFrom`. (see the original PR for the problematic case)
> 7. https://github.com/openjdk/panama-foreign/pull/846 Improve the documentation for variadic functions.
> 8. https://github.com/openjdk/panama-foreign/pull/849 Several test fixes to make sure the `jdk_foreign` tests can pass on 32-bit machines, taking linux-x86 as a test bed.
> 9. https://github.com/openjdk/panama-foreign/pull/850 Make the linker API required. The `Linker::nativeLinker` method is not longer allowed to throw an `UnsupportedOperationException` on ...

This pull request has now been integrated.

Changeset: 32ac72c3
Author:    Jorn Vernee <jvernee at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/32ac72c3d35138f5253e4defc948304ac3ea1b53
Stats:     4468 lines in 263 files changed: 2211 ins; 1196 del; 1061 mod

8312522: Implementation of Foreign Function & Memory API

Co-authored-by: Maurizio Cimadamore <mcimadamore at openjdk.org>
Co-authored-by: Jorn Vernee <jvernee at openjdk.org>
Co-authored-by: Per Minborg <pminborg at openjdk.org>
Reviewed-by: dholmes, psandoz, mcimadamore, alanb

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PR: https://git.openjdk.org/jdk/pull/15103