On Fri, 17 Mar 2023 15:38:49 GMT, Doug Simon <[email protected]> wrote:
>> This PR extends JVMCI with new API (`jdk.vm.ci.meta.Annotated`) for
>> accessing annotations. The main differences from
>> `java.lang.reflect.AnnotatedElement` are:
>> * All methods in the `Annotated` interface explicitly specify requested
>> annotation type(s). That is, there is no equivalent of
>> `AnnotatedElement.getAnnotations()`.
>> * Annotation data is returned in a map-like object (of type
>> `jdk.vm.ci.meta.AnnotationData`) instead of in an `Annotation` object. This
>> works better for libgraal as it avoids the need for annotation types to be
>> loaded and included in libgraal.
>>
>> To demonstrate the new API, here's an example in terms
>> `java.lang.reflect.AnnotatedElement` (which `ResolvedJavaType` implements):
>>
>> ResolvedJavaMethod method = ...;
>> ExplodeLoop a = method.getAnnotation(ExplodeLoop.class);
>> return switch (a.kind()) {
>> case FULL_UNROLL -> LoopExplosionKind.FULL_UNROLL;
>> case FULL_UNROLL_UNTIL_RETURN ->
>> LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN;
>> ...
>> }
>>
>>
>> The same code using the new API:
>>
>>
>> ResolvedJavaMethod method = ...;
>> ResolvedJavaType explodeLoopType = ...;
>> AnnotationData a = method.getAnnotationDataFor(explodeLoopType);
>> return switch (a.getEnum("kind").getName()) {
>> case "FULL_UNROLL" -> LoopExplosionKind.FULL_UNROLL;
>> case "FULL_UNROLL_UNTIL_RETURN" ->
>> LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN;
>> ...
>> }
>>
>>
>> The implementation relies on new methods in `jdk.internal.vm.VMSupport` for
>> parsing annotations and serializing/deserializing to/from a byte array. This
>> allows the annotation data to be passed from the HotSpot heap to the
>> libgraal heap.
>
> Doug Simon has updated the pull request incrementally with one additional
> commit since the last revision:
>
> [skip ci] formatting fixes
src/java.base/share/classes/jdk/internal/vm/VMSupport.java line 234:
> 232: * Encodes a list of annotations to a byte array. The byte array can
> be decoded with {@link #decodeAnnotations(byte[], AnnotationDecoder)}.
> 233: */
> 234: public static byte[] encodeAnnotations(Collection<Annotation>
> annotations) {
I don't think it matters much in this use case, but it looks like
encodeAnnotations could be changed to take a List rather than a Collection, as
the comment implies.
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PR Review Comment: https://git.openjdk.org/jdk/pull/12810#discussion_r1168913137
