> On 26 Feb 2017, at 13:08, Alan Bateman <alan.bate...@oracle.com> wrote:
>
> On 26/02/2017 11:20, Doug Simon wrote:
>
>> While trying to get upstream Graal working again with JDK 9, I'm having
>> problems with service loading. Graal uses a LayoutFactory service defined by
>> Truffle where the latter also includes a provider. The relevant parts of the
>> module-info descriptors are:
>>
>> module com.oracle.truffle.truffle_api {
>>
>> exports com.oracle.truffle.object;
>> exports com.oracle.truffle.object.basic;
>>
>> uses com.oracle.truffle.api.object.LayoutFactory;
>> provides com.oracle.truffle.api.object.LayoutFactory with
>> com.oracle.truffle.object.basic.DefaultLayoutFactory;
>>
>> }
>>
>> module jdk.internal.vm.compiler {
>> requires transitive com.oracle.truffle.truffle_api;
>> uses com.oracle.truffle.api.object.LayoutFactory;
>>
>> }
>>
>> However, looking up a provider in Graal[1] returns no providers. As far as I
>> understand service loading with modules, this is because
>> jdk.internal.vm.compiler is loaded via the platform class loader while
>> truffle is loaded via the app class loader as shown by the output of trace
>> statements I added:
>>
>> GraalTruffleRuntime.class.getClassLoader() ->
>> jdk.internal.loader.ClassLoaders$PlatformClassLoader@366e2eef
>> LayoutFactory.class.getClassLoader() ->
>> jdk.internal.loader.ClassLoaders$AppClassLoader@6df97b55
>>
>> This ability of a platform loaded class to depend on an app loaded class is
>> probably due to the soon-to-be-disabled mechanism[2] we use for overriding
>> the version of Graal bundled with JDK 9.
>>
>> Is there some command line magic I can use to make this case work now or do
>> I have to wait until [2] is addressed? If the latter, how will it work then?
>>
> An upgraded moduledefined to the platform loader can link to types in modules
> defined to the app loader. So I wouldn't expect issues there.
>
> Can you track down the code that uses ServiceLoader.load to load the
> LayoutFactory providers?
The code is in the first link of my previous message:
https://github.com/graalvm/graal-core/blob/1efc1c543acd7ed447c59788aeabc223be13e774/graal/org.graalvm.compiler.truffle/src/org/graalvm/compiler/truffle/GraalTruffleRuntime.java#L693
> It might be using loadInstalled or invoking it with the platform class loader
> and that would explain what you are seeing.
Thanks - using LayoutFactory.class.getClassLoader() works. So the general rule
is to use the leaf most class loader the service client knows about?
-Doug
