RFR: 8255150: Add utility methods to check long indexes and ranges [v2]

Roland Westrelin roland at openjdk.java.net
Thu Nov 5 15:47:31 UTC 2020


> This change add 3 new methods in Objects:
> 
> public static long checkIndex(long index, long length)
> public static long checkFromToIndex(long fromIndex, long toIndex, long length)
> public static long checkFromIndexSize(long fromIndex, long size, long length)
> 
> This mirrors the int utility methods that were added by JDK-8135248
> with the same motivations.
> 
> As is the case with the int checkIndex(), the long checkIndex() method
> is JIT compiled as an intrinsic. It allows the JIT to compile
> checkIndex to an unsigned comparison and properly recognize it as
> a range check that then becomes a candidate for the existing range check
> optimizations. This has proven to be important for panama's
> MemorySegment API and a prototype of this change (with some extra c2
> improvements) showed that panama micro benchmark results improve
> significantly.
> 
> This change includes:
> 
> - the API change
> - the C2 intrinsic
> - tests for the API and the C2 intrinsic
> 
> This is a joint work with Paul who reviewed and reworked the API change
> and filled the CSR.

Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - Jorn's comments
 - Update headers and add intrinsic to Graal test ignore list
 - move compiler test and add bug to test
 - non x86_64 arch support
 - c2 test case
 - intrinsic
 - Use overloads of method names.
   
   Simplify internally to avoid overload resolution
   issues, leverging List<Number> for the exception
   mapper.
 - Vladimir's comments
 - checkLongIndex

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1003/files
  - new: https://git.openjdk.java.net/jdk/pull/1003/files/74df12d3..b47184ac

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1003&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1003&range=00-01

  Stats: 11784 lines in 698 files changed: 6370 ins; 3584 del; 1830 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1003.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1003/head:pull/1003

PR: https://git.openjdk.java.net/jdk/pull/1003


More information about the core-libs-dev mailing list