RFR: 8164483: Generate field lambda forms at link time

[Claes Redestad]

On 2016-08-24 13:02, Vladimir Ivanov wrote:
> src/java.base/share/classes/java/lang/invoke/DirectMethodHandle.java
>
> +    @ForceInline
> +    /*non-public*/ static Unsafe unsafe() {
> +        return UNSAFE;
> +    }
> +
>
> +                    NF_unsafe = new NamedFunction(DirectMethodHandle.class
> +                            .getDeclaredMethod("unsafe"))
>
> No need for an accessor method. InvokerBytecodeGenerator already
> supports static field getters/setters [1]. You have to provide proper
> NamedFunction for MethodHandleStatics.UNSAFE.


Like so:

http://cr.openjdk.java.net/~redestad/8164483/webrev.02/

>
> Regarding LambdaForm.Kind, IMO field accessors push enum approach to the
> limit. Let's think about better ways to represent LF shape in a
> structured manner, but I'm fine with keeping it for future cleanup.

Agreed, this is begging for a better abstraction/structure.

Thanks!

/Claes

>
> Overall, looks good.
>
> Best regards,
> Vladimir Ivanov
>
> [1]
> http://hg.openjdk.java.net/jdk9/jdk9/jdk/file/496a116876a3/src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java#l931
>
>
> On 8/23/16 11:57 AM, Claes Redestad wrote:
>> Hi,
>>
>> this patch adds link-time generation of the simplest field lambda forms.
>> This avoid generating these forms during bootstrapping, which is
>> commonly done early on in even the simplest startup tests.
>>
>> To make this work, injecting Unsafe as a constant replacement had to be
>> replaced with a getter function, resulting in a few more bytecodes to do
>> the same thing, but which after inlining should turn into equivalent
>> code; performance testing indicate this change is performance neutral.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8164483
>> Webrev: http://cr.openjdk.java.net/~redestad/8164483/webrev.01/
>>
>> Together with JDK-8164569 (which I've tested together with this) this
>> removes all class generation from runtime in the tests associated with
>> JDK-8086045
>>
>> Thanks!
>>
>> /Claes