RFR: 8347408: Create an internal method handle adapter for system calls with errno [v4]

Per Minborg pminborg at openjdk.org
Mon Jan 13 09:04:25 UTC 2025


> Going forward, converting older JDK code to use the relatively new FFM API requires system calls that can provide `errno` and the likes to explicitly allocate a MemorySegment to capture potential error states. This can lead to negative performance implications if not designed carefully and also introduces unnecessary code complexity.
> 
> Hence, this PR proposes to add a _JDK internal_ method handle adapter that can be used to handle system calls with `errno`, `GetLastError`, and `WSAGetLastError`.
> 
> It currently relies on a thread-local cache of MemorySegments to allide allocations. If, in the future, a more efficient thread-associated allocation scheme becomes available, we could easily migrate to that one.
> 
> Tested and passed tiers 1-3.

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Remove thread test

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22391/files
  - new: https://git.openjdk.org/jdk/pull/22391/files/67a1deae..a1f3c723

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22391&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22391&range=02-03

  Stats: 105 lines in 1 file changed: 0 ins; 105 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22391.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22391/head:pull/22391

PR: https://git.openjdk.org/jdk/pull/22391


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