RFR: 8265518: C1: Intrinsic support for Preconditions.checkIndex [v2]

[Igor Veresov]

On Fri, 23 Apr 2021 03:50:54 GMT, Yi Yang <yyang at openjdk.org> wrote:

>> 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 incrementally with one additional commit since the last revision:
> 
>   remove java_nio_Buffer in javaClasses.hpp

src/hotspot/share/c1/c1_GraphBuilder.cpp line 2052:

> 2050:         return;
> 2051:       }
> 2052: 

Do we need to keep this flag?

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