RFR: 8265518: C1: Intrinsic support for Preconditions.checkIndex [v7]

Yi Yang yyang at openjdk.java.net
Thu May 6 10:14:16 UTC 2021


> The JDK codebase re-created many variants of checkIndex(`grep -I -r 'cehckIndex' jdk/`). A notable variant is java.nio.Buffer.checkIndex, which annotated with @IntrinsicCandidate and it only has a corresponding C1 intrinsic version.
> 
> In fact, there is an utility method `jdk.internal.util.Preconditions.checkIndex`(wrapped by java.lang.Objects.checkIndex) that behaves the same as these variants of checkIndex, we can replace these re-created variants of checkIndex by Objects.checkIndex, it would significantly reduce duplicated code and enjoys performance improvement because Preconditions.checkIndex is @IntrinsicCandidate and it has a corresponding intrinsic method in HotSpot.
> 
> But, the problem is currently HotSpot only implements the C2 version of Preconditions.checkIndex. To reuse it global-widely in JDK code, I think we can firstly implement its C1 counterpart. There are also a few kinds of stuff we can do later:
> 
> 1. Replace all variants of checkIndex by Objects.checkIndex in the whole JDK codebase.
> 2. Remove Buffer.checkIndex and obsolete/deprecate InlineNIOCheckIndex flag
> 
> Testing: cds, compiler and jdk

Yi Yang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - cmp clobbers its left argument on x86_32
 - Merge branch 'master' into consolidate_checkindex
 - better check1-4
 - AssertionError when expected exception was not thrown
 - remove extra newline
 - remove InlineNIOCheckIndex flag
 - remove java_nio_Buffer in javaClasses.hpp
 - consolidate

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

Changes: https://git.openjdk.java.net/jdk/pull/3615/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3615&range=06
  Stats: 331 lines in 11 files changed: 235 ins; 78 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3615.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3615/head:pull/3615

PR: https://git.openjdk.java.net/jdk/pull/3615


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