RFD: C2: Poor code quality for Unsafe

[Andrew Haley]

On 27/07/16 15:08, Paul Sandoz wrote:
> Ah, ok, i did not realize you had that patch applied as well, i was thrown off base because you mentioned the following method:
> 
>    protected int ix(int i) {
>        return (i << $LG_BYTES_PER_VALUE$) + offset;
>    }
> 
> which is not used for access [*] in the patch(s).

It *is* used in Direct-X-Buffer, which is what gets inlined.  The
inlining looks like this:

                            @ 18   ByteBufferTest::floss (24 bytes)   inline (hot)
                              @ 4   java.nio.Buffer::capacity (5 bytes)   accessor
                              @ 13   java.nio.DirectIntBufferU::put (18 bytes)   inline (hot)
                                @ 6   java.nio.Buffer::checkIndex (22 bytes)   inline (hot)
                                @ 9   java.nio.DirectIntBufferU::ix (10 bytes)   inline (hot)
                                @ 13   jdk.internal.misc.Unsafe::putInt (8 bytes)   force inline by annotation
                                  @ 4   jdk.internal.misc.Unsafe::putInt (0 bytes)   (intrinsic)
                              @ 4   java.nio.Buffer::capacity (5 bytes)   accessor

I can confirm that your corrected patch makes no difference to any of
this.

Andrew.