hg: lambda/lambda/jdk: 3 new changesets

[Rémi Forax]

On 04/22/2012 04:55 PM, Brian Goetz wrote:
> I think this will work too.  I think there's an even simpler way, too 
> -- make the factory() method part of the same class, and have its 
> signature be
>
>   factory(MethodHandle, Class, Object[]))
>
> and curry the method handle and class on with 2x bindTo or insertArgs. 
> Then just wrap a handle to factory in a ConstantCallSite and be done.

In that case you need to call MethodHandle.invokeWithArguments in the 
method factory() and
this call is currently slow and even if its implementation is faster the 
VM can still decide
to not inline the call.

Rémi

>
> On 4/22/2012 9:30 AM, Rémi Forax wrote:
>> On 04/22/2012 12:23 PM, Rémi Forax wrote:
>>> On 04/21/2012 11:58 PM, brian.goetz at oracle.com wrote:
>>>> Changeset: 59aa44ba1555
>>>> Author:    briangoetz
>>>> Date:      2012-04-21 17:56 -0400
>>>> URL:       
>>>> http://hg.openjdk.java.net/lambda/lambda/jdk/rev/59aa44ba1555
>>>>
>>>> Minor improvements in combo-test framework and lambda tests
>>>>
>>>> ! combo-tests/build.xml
>>>> ! combo-tests/tests/tools/javac/combo/JavacTemplateTestBase.java
>>>> ! combo-tests/tests/tools/javac/combo/Template.java
>>>> ! combo-tests/tests/tools/javac/lambda/LambdaConversionTest.java
>>>>
>>>> Changeset: b166fa7adaea
>>>> Author:    briangoetz
>>>> Date:      2012-04-21 17:56 -0400
>>>> URL:       
>>>> http://hg.openjdk.java.net/lambda/lambda/jdk/rev/b166fa7adaea
>>>>
>>>> Minor improvements in combo-test framework and lambda tests
>>>>
>>>> ! test-ng/build.xml
>>>> ! test-ng/tests/org/openjdk/tests/java/util/functions/MappersTest.java
>>>>
>>>> Changeset: d0e63cae6a1c
>>>> Author:    briangoetz
>>>> Date:      2012-04-21 17:57 -0400
>>>> URL:       
>>>> http://hg.openjdk.java.net/lambda/lambda/jdk/rev/d0e63cae6a1c
>>>>
>>>> Allow metafactory option to be choosable at runtime via 
>>>> lambda.metafactory system property; first cut at second translation 
>>>> strategy (method handle proxies)
>>>>
>>>> ! .hgignore
>>>> ! src/share/classes/java/lang/invoke/InnerClassGenerator.java
>>>> ! src/share/classes/java/lang/invoke/LambdaMetafactory.java
>>>> + src/share/classes/java/lang/invoke/MagicLambdaImpl.java
>>>> ! src/share/classes/java/lang/invoke/MethodHandleProxies.java
>>>> + 
>>>> src/share/classes/java/lang/invoke/MethodHandleProxyLambdaMetafactory.java
>>>>
>>>>
>>> Hi Brian,
>>> I think you don't need the MhMetafactoryCallSite because
>>> the arguments of MethodHandle.asInterfaceInstance are known during the
>>> bootstrap.
>>> The idea is that instead of the method factory,() you can bind the
>>> method bindTo itself.
>>> I will try to come with a code, it will be more clear :)
>>>
>>> Rémi
>>
>> I propose something like this
>> (I have not tested it, I will test it tomorrow at my office :)
>>
>> static CallSite mhProxyMetafactory(MethodHandles.Lookup caller,
>>                                          MethodType invokedType,
>>                                          MethodHandleInfo samInfo,
>>                                          MethodHandleInfo implInfo,
>>                                          MethodHandle impl) {
>>           Class<?>  samBase = invokedType.returnType();
>>
>>           // @@@ Special bindTo case for count=1&&  isInstance
>>
>>           if (invokedType.parameterCount() == 0) {
>>               return new 
>> ConstantCallSite(MethodHandles.constant(samBase,
>>
>> MethodHandleProxies.asInterfaceInstance(samBase, impl)));
>>           }
>>
>>           return new ConstantCallSite(
>>               ProxyMetaFactory.createProxyCreatorMethodHandle(samBase,
>> impl, invokedType));
>>
>>           /*
>>           else {
>>               try {
>>                   return new MhMetafactoryCallSite(impl, invokedType,
>> samBase);
>>               }
>>               catch (Throwable e) {
>>                   log("Exception constructing Lambda factory 
>> callsite", e);
>>                   throw new LambdaConversionException("Error 
>> constructing
>> CallSite", e);
>>               }
>>           }*/
>>       }
>>
>>       static class ProxyMetaFactory {
>>         private static final MethodHandle INSERT_ARGUMENTS;
>>         private static final MethodHandle AS_INTERFACE_INSTANCE;
>>
>>         static {
>>           Lookup lookup = MethodHandles.Lookup.IMPL_LOOKUP;
>>           MethodHandle insertArguments;
>>           try {
>>             insertArguments = lookup.findStatic(MethodHandles.class,
>> "insertArguments",
>>                 MethodType.methodType(MethodHandle.class,
>> MethodHandle.class, int.class, Object[].class));
>>             AS_INTERFACE_INSTANCE =
>> lookup.findStatic(MethodHandleProxies.class, "asInterfaceInstance",
>>                 MethodType.methodType(Object.class, Class.class,
>> MethodHandle.class));
>>           } catch (NoSuchMethodException | IllegalAccessException e) {
>>             throw new AssertionError(e);
>>           }
>>
>>           // specialize to always insert at position 0
>>           INSERT_ARGUMENTS =
>> MethodHandles.insertArguments(insertArguments, 1, 0);
>>         }
>>
>>         static MethodHandle createProxyCreatorMethodHandle(Class<?>
>> samBase, MethodHandle impl, MethodType invokedType) {
>>           // curry the SAM class
>>           MethodHandle asInterFaceInstance =
>> MethodHandles.insertArguments(AS_INTERFACE_INSTANCE, 0, samBase);
>>           // the target of fold must have at least the same parameter
>> types as the combiner
>>           asInterFaceInstance =
>> MethodHandles.dropArguments(asInterFaceInstance, 1,
>> invokedType.parameterList());
>>
>>           // curry the method handle impl
>>           MethodHandle insertArgument =
>> MethodHandles.insertArguments(INSERT_ARGUMENTS, 0, impl);
>>           // adapt to the callsite signature
>>           MethodHandle combiner =
>> insertArgument.asCollector(Object[].class, 
>> invokedType.parameterCount()).
>>                                                  asType(invokedType);
>>
>>           return MethodHandles.foldArguments(asInterFaceInstance, 
>> combiner);
>>         }
>>       }
>>
>> cheers,
>> Rémi
>>
>>