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

[Martin Doerr]

> 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

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16179/files
  - new: https://git.openjdk.org/jdk/pull/16179/files/cba58ed0..17b300ce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16179&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16179&range=02-03

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16179.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16179/head:pull/16179

PR: https://git.openjdk.org/jdk/pull/16179