Port of: https://github.com/openjdk/panama-foreign/pull/901
Original PR body: > This PR adds more javadoc to explain how base offsets in var handles obtained > from layouts can be used. > > First, a number of examples in the main `MemoryLayout` javadoc is rectified, > as such examples did not use the additional base offset parameter (and were > hence incorrect). > > Second, the var handles part in the `MemorySegment` section on "accessing > memory segment" has been rewritten to avoid duplication with the concepts > exposed in `MemoryLayout`. Now we show how `MemorySegment::get` and > `MemorySegment::getAtIndex` can be obtained using basic var handles and > combinators. We mention that more complex var handles can be obtained using > layout paths, but we now just reference the layout path section. > > Last, I've added a new section on the `MemoryLayout` javadoc, with an example > on how to deal with variable-length structs. This example showcases how var > handles can be used in intricate situations, and combined with the new > `scaleOffset` method. ------------- Commit messages: - Beef up javadoc for base offset in var handles derived from layouts Changes: https://git.openjdk.org/jdk/pull/16127/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16127&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8317824 Stats: 123 lines in 2 files changed: 78 ins; 17 del; 28 mod Patch: https://git.openjdk.org/jdk/pull/16127.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16127/head:pull/16127 PR: https://git.openjdk.org/jdk/pull/16127
