RFR: 8367129: Move input validation checks to Java for java.lang.StringLatin1 intrinsics [v2]

[Raffaello Giulietti]

On Thu, 12 Feb 2026 16:11:25 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> Moves input validation checks to Java for `java.lang.StringLatin1` intrinsics. While doing so, affected `java.lang.StringUTF16` methods needed to be updated due to relaxed checks at intrinsics. The javadocs of the touched methods are extensively overhauled.
>
> Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Apply review feedback

src/java.base/share/classes/java/lang/StringUTF16.java line 407:

> 405:      * @param srcOff the index (inclusive) of the first character in {@code src}
> 406:      * @param dst the target Latin-1 string byte array
> 407:      * @param srcOff the index (inclusive) of the first character in {@code dst}

Suggestion:

     * @param dstOff the index (inclusive) of the first character in {@code dst}

src/java.base/share/classes/java/lang/StringUTF16.java line 437:

> 435: 
> 436:     /**
> 437:      * Copies the prefix of Latin-1 characters from a UTF-16 string byte array

Since there are offsets, strictly speaking this is not a prefix but a general subrange.

src/java.base/share/classes/java/lang/StringUTF16.java line 499:

> 497: 
> 498:     @IntrinsicCandidate
> 499:     static void getChars(byte[] value, int srcBegin, int srcEnd, char[] dst, int dstBegin) {

What about this intrinsic? It doesn't seem to follow the conventions about `private` and a gatekeeper method.

src/java.base/share/classes/java/lang/StringUTF16.java line 623:

> 621:         Objects.requireNonNull(other);
> 622:         checkOffset(len1, value);
> 623:         String.checkOffset(len2, StringLatin1.length(other));

FYI, all these checks are already performed in the called (non-intrinsic) method.

src/java.base/share/classes/java/lang/StringUTF16.java line 726:

> 724:     static int compareToCI_Latin1(byte[] value, byte[] other) {
> 725:         Objects.requireNonNull(value);
> 726:         Objects.requireNonNull(other);

FYI, checks are already performed in the called method.

src/java.base/share/classes/java/lang/StringUTF16.java line 892:

> 890:     }
> 891: 
> 892:     private static int indexOfUnsafe(byte[] value, int valueToIndex, byte[] str, int strToIndex, int valueFromIndex) {

I think this method requires documentation about what it assumes about the arguments.
While it can be somehow derived from its usages, it would help to have it located here.

src/java.base/share/classes/java/lang/StringUTF16.java line 981:

> 979:     }
> 980: 
> 981:     private static int indexOfLatin1Unsafe(byte[] src, int srcCount, byte[] tgt, int tgtCount, int fromIndex) {

Similarly to above, documenting the expectations about the arguments here would help.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804366706
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804382508
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804368864
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804413083
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804428055
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804470315
PR Review Comment: https://git.openjdk.org/jdk/pull/28832#discussion_r2804488037