RFR JDK-8223347 Integration of Vector API (Incubator): Java API, implementation, and tests

[Remi Forax]

BTW, did you try to add an intermediary private non visible class between Vector and IntVector to avoid all hand-written cast inside the implementation of IntVector,
something along that line

  public abstract class Vector<E> {
    abstract  void foo(Vector<E> vector);
    abstract Vector<E> bar();
  }

  /* non public */ abstract class AbstractVector<E, V extends AbstractVector<E, V>> extends Vector<E> {
    public abstract void foo(V vector);
    public final void foo(Vector<E> vector) {   // bridge by hand
      foo((V)vector);
    }
    public abstract V bar();
  }

  public abstract class IntVector extends AbstractVector<Integer, IntVector> {

  }

Rémi

----- Mail original -----
> De: "Paul Sandoz" <paul.sandoz at oracle.com>
> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>, "hotspot-dev" <hotspot-dev at openjdk.java.net>
> Envoyé: Jeudi 2 Avril 2020 00:46:55
> Objet: RFR JDK-8223347 Integration of Vector API (Incubator): Java API, implementation, and tests

> Hi,
> 
> A prior email sent out a request for review of the Vector API in preparation for
> JEP 338: Vector API (Incubator) [1] to be proposed for target:
> 
>  https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-March/065345.html
>  <https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-March/065345.html>
> 
> This email expands the review of the API to the Java implementation and Java
> tests:
> 
>  http://cr.openjdk.java.net/~psandoz/panama/JDK-8223347-vector-api-integration-java/jdk_src_webrev/webrev/
>  <http://cr.openjdk.java.net/~psandoz/panama/JDK-8223347-vector-api-integration-java/jdk_src_webrev/webrev/>
> 
>  http://cr.openjdk.java.net/~psandoz/panama/JDK-8223347-vector-api-integration-java/jdk_test_webrev/webrev/
>  <http://cr.openjdk.java.net/~psandoz/panama/JDK-8223347-vector-api-integration-java/jdk_test_webrev/webrev/>
> 
> (Further emails will sent for review of general HotSpot changes CPU architecture
> specific HotSpot changes, x64 and aarch64, and performance tests.  For an early
> peek see the links in the description of JDK-8223347.)
> 
> —
> 
> The Vector API provides
> 
> - the public Vector class with vector operations common to all supported
> primitive types
> 
> - public primitive specializations, such as IntVector, with common operations
> associated with the primitive type
> 
> - internal concrete specializations for the vector size, such as Int256Vector,
> for a vector holding 8 ints.
> 
> Operations generally defer to one of approximately 20 vector intrinsics.  Some
> operations may be composed of other operations.
> 
> Explicit casts are performed by vector operations to ensure vectors arguments
> are of the required shape (bit size) and element type.
> 
> A vector intrinsic is an internal low-level vector operation. The last argument
> to the intrinsic is fall back behavior in Java, implementing the scalar
> operation over the number of elements held by the vector.  Thus, If the
> intrinsic is not supported in C2 for the other arguments then the Java
> implementation is executed (the Java implementation is always executed when
> running in the interpreter or for C1).
> 
> The public primitive specializations and the internal concrete implementations
> are generated from SSP template files, X-Vector.java.template and
> X-VectorBits.java.template respectively.
> 
> Overall the implementation approach is quite formulaic and rather repetitive.
> Once you grok the pattern It should be easier to review if a little laborious.
> 
> Unit tests are auto-generated by composing templates for each operation into an
> SSP template file which is then used to generate unit test files for each
> concrete vector class.  The tests are quite extensive and have found many a
> HotSpot issue in development across a wide range of platforms.
> 
> Paul.
> 
> [1] https://bugs.openjdk.java.net/browse/JDK-8201271
> <https://bugs.openjdk.java.net/browse/JDK-8201271>