On Tue, 12 Sep 2023 10:49:38 GMT, Jorn Vernee <jver...@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 `UnsupportedO... > > Jorn Vernee has updated the pull request incrementally with two additional > commits since the last revision: > > - add missing space + reflow lines > - Fix typo > > Co-authored-by: ExE Boss <3889017+exe-b...@users.noreply.github.com> src/java.base/share/classes/jdk/internal/foreign/abi/fallback/FallbackLinker.java line 311: > 309: }; > 310: > 311: CANONICAL_LAYOUTS = Map.ofEntries( `LibFallback::wcharSize()` and other getters for `LibFallback.NativeConstants` fields can throw an error when `LibFallback.SUPPORTED` is `false` due to the `fallbackLinker` library not being present, so this static initializer should be made into a method instead: Suggestion: static final Map<String, MemoryLayout> CANONICAL_LAYOUTS = initCanonicalLayouts(); private static Map<String, MemoryLayout> initCanonicalLayouts() { if (!isSupported()) { return null; } int wchar_size = LibFallback.wcharSize(); MemoryLayout wchartLayout = switch(wchar_size) { case 2 -> JAVA_CHAR; // prefer JAVA_CHAR default -> FFIType.layoutFor(wchar_size); }; return Map.ofEntries( ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/15103#discussion_r1324996396
