RFR: 8361842: Validate input in both Java and C++ for java.lang.StringCoding intrinsics

[ExE Boss]

On Fri, 27 Jun 2025 13:24:52 GMT, Chen Liang <liach at openjdk.org> wrote:

>> But the original code already checks for `len >= 0`, right? See `LibraryCallKit::inline_countPositives` -> `generate_string_range_check` -> `// Offset and count must not be negative`
>> 
>> This PR is about moving the range checks from the intrinsics into the Java wrappers. Removing range checks is out of the scope and should be carefully evaluated on a case-by-case basis separately.
>
> My point is this is a performance-sensitive API. We are using a known-slow check method `checkFromIndexSize` which may introduce a performance regression.

Maybe use `jdk.internal.util.Preconditions` directly instead?
Suggestion:

        Preconditions.checkFromIndexSize(off, len, ba.length, null);

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PR Review Comment: https://git.openjdk.org/jdk/pull/25998#discussion_r2172823303