On Tue, 24 May 2022 15:28:27 GMT, Maurizio Cimadamore <[email protected]>
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/java/lang/foreign/MemoryLayout.java line 374:
> 372: *
> 373: * Additionally, the provided dynamic values must conform to some
> bound which is derived from the layout path, that is,
> 374: * {@code 0 <= x_i <= b_i}, where {@code 0 <= i <= n}, or {@link
> IndexOutOfBoundsException} is thrown.
Suggestion:
* {@code 0 <= x_i < b_i}, where {@code 1 <= i <= n}, or {@link
IndexOutOfBoundsException} is thrown.
We refer later to `B` being an exclusive upper bound (computed using `ceilDiv`).
-------------
PR: https://git.openjdk.java.net/jdk/pull/8868
