System.arraycopy

[Deneau, Tom]

I did some tweaking to our HSAILHotSpotReplacementsImpl to basically make it always use the non-foreign-call version (UnsafeArrayCopy) rather than the foreign-call version, regardless of the sense of the global flag CallArrayCopy.  This seems to  cover most of the arraycopy cases.

The one case that this not handle is a "non-exact" Object Array copy, for instance copying and array of Strings to an array of Objects.

I see the snippet code for this "generic array copy" does as shown below and I believe we are taking the genericObjectCallCounter path.  So we still fail with

  com.oracle.graal.graph.GraalGraphInternalError com.oracle.graal.compiler.common.GraalInternalError: unimplemented
	at node: 78|Invoke#Direct#System.arraycopy

(I guess this doesn't get replaced by a snippet since it is already in a snippet?

So my question is:  Is there any java implementation of this path?  Or any solution that would not involve a foreign call, etc.

-- Tom

=================
    @Snippet
    public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length) {
        Object nonNullSrc = guardingNonNull(src);
        Object nonNullDest = guardingNonNull(dest);
        Word srcHub = loadHub(nonNullSrc);
        Word destHub = loadHub(nonNullDest);
        if (probability(FAST_PATH_PROBABILITY, srcHub.equal(destHub)) && probability(FAST_PATH_PROBABILITY, nonNullSrc != nonNullDest)) {
            int layoutHelper = checkArrayType(srcHub);
            final boolean isObjectArray = ((layoutHelper & layoutHelperElementTypePrimitiveInPlace()) == 0);

            checkLimits(nonNullSrc, srcPos, nonNullDest, destPos, length);
            if (probability(FAST_PATH_PROBABILITY, isObjectArray)) {
                genericObjectExactCallCounter.inc();
                UnsafeArrayCopyNode.arraycopy(nonNullSrc, srcPos, nonNullDest, destPos, length, Kind.Object);
            } else {
                genericPrimitiveCallCounter.inc();
                UnsafeArrayCopyNode.arraycopyPrimitive(nonNullSrc, srcPos, nonNullDest, destPos, length, layoutHelper);
            }
        } else {
            genericObjectCallCounter.inc();
            System.arraycopy(nonNullSrc, srcPos, nonNullDest, destPos, length);
        }
    }


> -----Original Message-----
> From: Deneau, Tom
> Sent: Thursday, June 05, 2014 6:29 PM
> To: 'Tom Rodriguez'
> Cc: Chris Thalinger; graal-dev at openjdk.java.net
> Subject: RE: System.arraycopy
> 
> Using -G:-CallArrayCopy seemed to work...
> 
> > -----Original Message-----
> > From: Tom Rodriguez [mailto:tom.rodriguez at oracle.com]
> > Sent: Thursday, June 05, 2014 4:44 PM
> > To: Deneau, Tom
> > Cc: Chris Thalinger; graal-dev at openjdk.java.net
> > Subject: Re: System.arraycopy
> >
> >
> > On Jun 5, 2014, at 2:39 PM, Deneau, Tom <tom.deneau at amd.com> wrote:
> >
> > > Christian --
> > >
> > > For now just going for functionally correct, will address
> > > performance
> > issues in the future.  But yes there are vector instructions that
> > could help even in a single workitem.
> > >
> > > Is there already a pure java implementation of System.arrayCopy we
> > could substitute?
> >
> > UnsafeArrayCopyNode is pretty much that.  The flag CallArrayCopy
> > controls whether it prefers the hotspot stubs for array copy or not
> > but it should be able to fall back to UnsafeArrayCopyNode.
> >
> > tom
> >
> > >
> > > I guess we would want to use the logic to do different substitutions
> > based on the type of the array (like in ArrayCopySnippets)?
> > >
> > > any other advice for implementing this?
> > >
> > > -- Tom
> > >
> > >
> > >
> > >> -----Original Message-----
> > >> From: Christian Thalinger [mailto:christian.thalinger at oracle.com]
> > >> Sent: Thursday, June 05, 2014 3:45 PM
> > >> To: Deneau, Tom
> > >> Cc: graal-dev at openjdk.java.net
> > >> Subject: Re: System.arraycopy
> > >>
> > >> Well, I guess the easiest but maybe not most performant way would
> > >> be to have a substitution and implement it in plain Java.
> > >>
> > >> On the other hand you could rely on vectorization and the power of
> > >> GPUs to produce good, parallel code :-)
> > >>
> > >> On Jun 5, 2014, at 1:29 PM, Deneau, Tom <tom.deneau at amd.com> wrote:
> > >>
> > >>> Since we cannot handle "foreign calls" in the hsail backend, what
> > >>> is
> > >> the preferred way to implement System.arraycopy?  Right now, we are
> > >> deferring to the host and so getting an ArrayCopyCallNode which
> > >> gets lowered to a graph containing a ForeignCallNode.
> > >>>
> > >>> I confess to being a little confused with the ArrayCopyNode and
> > >> Snippets, UnsafeArrayCopyNode and Snippets, ArrayCopyCallNode, etc.
> > >>>
> > >>> -- Tom
> > >>>
> > >