RFR: 8287244: Add bound check in indexed memory access var handle [v2]
Paul Sandoz
psandoz at openjdk.java.net
Tue May 24 16:52:59 UTC 2022
On Tue, 24 May 2022 15:28:27 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:
>> Constructing indexed var handles using the `MemoryLayout` API produces `VarHandle` which do not check the input indices for out-of-bounds conditions.
>> While this can never result in a VM crash (after all the memory segment will protect against "true" OOB access), it is still possible for an access expression to refer to parts of a segment that are logically unrelated.
>>
>> This patch adds a "logical" bound check to all indexed var handles generated using the layout API.
>> Benchmarks are not affected by the check. Users are still able to create custom "unchecked" var handles, using the combinator API in `MethodHandles`.
>
> Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:
>
> Tweak javadoc for ValueLayout::arrayElementVarHandle
src/java.base/share/classes/jdk/internal/foreign/LayoutPath.java line 256:
> 254: private long[] addBound(long maxIndex) {
> 255: long[] newBounds = new long[bounds.length + 1];
> 256: System.arraycopy(bounds, 0, newBounds, 0, bounds.length);
Suggestion:
long[] newBounds = Arrays.copyOf(bounds, bounds.length + 1);
-------------
PR: https://git.openjdk.java.net/jdk/pull/8868
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