Adopting JEP 303 (Intrinsics for LDC and INVOKEDYNAMIC) into Amber

[Tagir Valeev]

Thanks! Works fine for me.

With best regards,
Tagir Valeev.

On Thu, Apr 20, 2017 at 8:37 PM, Vicente Romero <vicente.romero at oracle.com>
wrote:

> Hi all,
>
> I have just pushed a patch that converts class literals into a poly
> expression. Meaning that now you can pass a class literal where a
> ClassConstant is expected. This will simplify the use of the API making the
> user code less verbose. Taking as an example the test case sent by Tagir,
> it could be now rewritten as:
>
> import java.lang.invoke.*;
> import java.lang.invoke.Constables.*;
> import java.lang.reflect.*;
>
> public class MH {
>   private static void test() {
>     System.out.println("Hello");
>   }
>
>   public static void main(String[] args) throws Throwable {
>     final MethodHandle handle = Intrinsics.ldc(
>      MethodHandleConstant.ofStatic(MH.class, "test",
> MethodTypeConstant.of(void.class)));
>     handle.invokeExact();
>   }
> }
>
> Thanks,
> Vicente
>
>
>
> On 04/18/2017 11:14 PM, Tagir Valeev wrote:
>
> Thank you for the hint! It also seems that ClassConstant.of(MH.class) does
> not work either and VarHandles are not supported yet. However the following
> sample finally worked for me:
>
>
> import java.lang.invoke.*;
> import java.lang.invoke.Constables.*;
> import java.lang.reflect.*;
>
> public class MH {
>   private static void test() {
>     System.out.println("Hello");
>   }
>
>   public static void main(String[] args) throws Throwable {
>     final MethodHandle handle = Intrinsics.ldc(
>      MethodHandleConstant.ofStatic(ClassConstant.of("LMH;"), "test",
> MethodTypeConstant.of(ClassConstant.of("V"))));
>     handle.invokeExact();
>   }
> }
>
> With best regards,
> Tagir Valeev.
>
>
> On Tue, Apr 18, 2017 at 9:13 PM, Brian Goetz <brian.goetz at oracle.com>
> wrote:
>
>> The primitive fields (Constables.VOID and friends) are not yet hooked up;
>> for the time being, replace with ClassConstant.of("V").
>>
>>
>> On 4/18/2017 2:17 AM, Tagir Valeev wrote:
>>
>>> Hello!
>>>
>>> I tried to play with this, but still no success. Fresh build from
>>> constant-folding branch. I tried to compile the following files:
>>>
>>> // MH.java
>>>
>>> import java.lang.invoke.*;
>>> import java.lang.invoke.Constables.*;
>>> import java.lang.reflect.*;
>>>
>>> public class MH {
>>>    private static void test() {
>>>      System.out.println("Hello");
>>>    }
>>>
>>>
>>>    public static void main(String[] args) throws Throwable {
>>>      final MethodHandle handle = Intrinsics.ldc(
>>>       MethodHandleConstant.ofStatic(ClassConstant.of(MH.class), "test",
>>> MethodTypeConstant.of(Constables.VOID)));
>>>      handle.invokeExact();
>>>    }
>>>
>>> }
>>>
>>> // VH.java
>>> import java.lang.invoke.*;
>>> import java.lang.invoke.Constables.*;
>>> import java.lang.reflect.*;
>>>
>>> public class VH {
>>>    private static volatile int counter;
>>>
>>>    private static final VarHandle COUNTER = Intrinsics.ldc(
>>>       VarHandleConstant.ofStaticField(ClassConstant.of(VH.class),
>>> "counter",
>>> Constables.INT));
>>>
>>>    public static void main(String[] args) {
>>>      System.out.println(COUNTER.getAndAdd(1));
>>>      System.out.println(COUNTER.getAndAdd(1));
>>>    }
>>> }
>>>
>>> Building with "javac -XDdoConstantFold=true MH.java" or "javac
>>> -XDdoConstantFold=true VH.java",
>>> javac silently exists without producing .class file or reporting any
>>> error.
>>> Tried with -verbose, the output ends like this:
>>>
>>> [loading /modules/java.base/java/lang/annotation/RetentionPolicy.class]
>>> [loading /modules/java.base/java/lang/annotation/Target.class]
>>> [loading /modules/java.base/java/lang/annotation/ElementType.class]
>>> [checking VH]
>>> [loading /modules/java.base/java/io/Serializable.class]
>>> [loading /modules/java.base/java/lang/AutoCloseable.class]
>>> [loading /modules/java.base/java/lang/Class.class]
>>> [loading /modules/java.base/java/lang/invoke/Constable.class]
>>> [loading /modules/java.base/java/lang/invoke/Intrinsics.class]
>>> [total 1484ms]
>>>
>>> Without  -XDdoConstantFold=true the class file is produced and dies like
>>>
>>> Exception in thread "main" java.lang.UnsupportedOperationException: no
>>> reflective access
>>> at java.base/java.lang.invoke.Intrinsics.ldc(Intrinsics.java:42)
>>> at MH.main(MH.java:12)
>>>
>>> Which is expected behavior, I guess.
>>>
>>> Am I doing something wrong? Could you compile these files on your side?
>>> Sorry if my tries look lame: I'm very new to this.
>>>
>>> With best regards,
>>> Tagir Valeev.
>>>
>>> On Tue, Apr 18, 2017 at 9:07 AM, Vicente Romero <
>>> vicente.romero at oracle.com>
>>> wrote:
>>>
>>> Hi,
>>>>
>>>> Support for JEP 303 has been pushed in the amber repo [1, 2] (branch
>>>> name
>>>> is 'constant-folding'). The development is mature although there are
>>>> some
>>>> fresh areas like using reflection for accessing the API methods.
>>>> Reflection
>>>> is needed as the classes defined in the API see [1] are not available in
>>>> the boot JDK. There is still some ongoing research so some changes to
>>>> the
>>>> API and the code are to be expected in the near future,
>>>>
>>>> Thanks,
>>>> Vicente
>>>>
>>>>
>>>> [1] http://hg.openjdk.java.net/amber/amber/jdk/rev/2eeb80b82c9c
>>>> [2] http://hg.openjdk.java.net/amber/amber/langtools/rev/7be70b52c760
>>>>
>>>>
>>>> On 04/17/2017 04:22 PM, Brian Goetz wrote:
>>>>
>>>> JEP 303 (Intrinsics for LDC and INVOKEDYNAMIC) is hereby adopted into
>>>>> Project Amber.
>>>>>
>>>>> A first draft of the API can be found at:
>>>>>
>>>>>      http://cr.openjdk.java.net/~briangoetz/JDK-8178320/webrev/
>>>>>
>>>>> Prototype implementation coming soon.
>>>>>
>>>>>
>>>>>
>>>>>
>>
>
>