Panama unresolved error when instantiating wayland struct...

Fri Feb 15 00:14:44 UTC 2019

Here's the bug reference I've created:

https://bugs.openjdk.java.net/browse/JDK-8219042

unfortunately, I tried allocating the structs in different order and the 
problem cannot be resolved at the client side.

Maurizio

On 15/02/2019 00:06, Mark Hammons wrote:
> I previously allocated a wl_list in my code. I'm still new to the 
> foreign interfaces, so I'm not aware if there's a way to allocate the 
> wl_listener using a pre-allocated wl_list.
>
> Mark
>
> On 2/15/19 12:49 AM, Maurizio Cimadamore wrote:
>>
>> On 14/02/2019 23:38, Mark Hammons wrote:
>>> Hi Maurizio,
>>>
>>> No, wl_list is defined in wayland_utils.h while wl_listener is in 
>>> wayland_server_core.h. I am currently looking through the issues on 
>>> the openjdk tracker and seeing if there's a mitigation for this.
>>
>> Right - you beat me to this:
>>
>> https://people.freedesktop.org/~whot/wayland-doxygen/wayland/Server/structwl__listener.html 
>>
>>
>> and
>>
>> https://people.freedesktop.org/~whot/wayland-doxygen/wayland/Server/structwl__list.html 
>>
>>
>> Unfortunately this issue is not easy to workaround. I'll make sure to 
>> create a JBS entry for it (we do have one, but it's probably not 
>> visible outside).
>>
>> I'll also try to play with this a bit to see what can be done - with 
>> this issue sometimes it helps to allocate the inner struct first 
>> (e.g. wl_list), and then the one that depends on it (e.g. wl_listener).
>>
>> Maurizio
>>
>>>
>>> ~Mark
>>>
>>> On 2/15/19 12:30 AM, Maurizio Cimadamore wrote:
>>>> Hi Mark,
>>>> thanks for the report - from the looks of it, it seems an issue 
>>>> with cross-header layout resolution, which is listed in the 'known 
>>>> issues' in the EA page:
>>>>
>>>> "Dynamic layout resolution doesn't work across multiple headers."
>>>>
>>>> I will check in more details tomorrow, and confirm, one way or 
>>>> another.
>>>>
>>>> Quick check: are wl_list and wl_listener defined in the same header 
>>>> file? If not that's likely the issue here.
>>>>
>>>> I think Pointer<?> is the correct type - jextract tries to insert 
>>>> as more general types as possible when inserting Pointer in 
>>>> argument position; if it generated Pointer<Void>, and that was an 
>>>> ordinary function call, you could only call it with another 
>>>> Pointer<Void> - if the argument type is Pointer<?> you can pass 
>>>> _any_ pointer - e.g. Pointer<Byte>, Pointer<Integer> which is kind 
>>>> of close to what you can do in C.
>>>>
>>>> Maurizio
>>>>
>>>> On 14/02/2019 22:23, Mark Hammons wrote:
>>>>> Hi all,
>>>>>
>>>>> I decided to try to take the dive on project panama, starting with 
>>>>> making a binding to linux's wayland server. I used the following 
>>>>> command: ~/bin/jdk-13/bin/jextract 
>>>>> /usr/include/wayland/wayland-server-core.h 
>>>>> /usr/include/wayland/wayland-server.h 
>>>>> /usr/include/wayland/wayland-util.h 
>>>>> /usr/include/wayland/wayland-version.h 
>>>>> /usr/include/wayland/wayland-server-protocol.h -I 
>>>>> /usr/include/wayland -L /usr/lib64/ --record-library-path -l 
>>>>> wayland-server -t wayland -o wayland_server.jar
>>>>>
>>>>>
>>>>> When I try to allocate a wl_listener struct, I get the following 
>>>>> error:
>>>>>
>>>>> [error] Exception in thread "main" 
>>>>> java.lang.UnsupportedOperationException: bitsSize on Unresolved
>>>>> [error]     at 
>>>>> java.base/java.foreign.layout.Unresolved.bitsSize(Unresolved.java:76)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.ReferencePipeline$5$1.accept(ReferencePipeline.java:229)
>>>>> [error]     at 
>>>>> java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.LongPipeline.reduce(LongPipeline.java:474)
>>>>> [error]     at 
>>>>> java.base/java.util.stream.LongPipeline.sum(LongPipeline.java:432)
>>>>> [error]     at 
>>>>> java.base/java.foreign.layout.Group.bitsSize(Group.java:119)
>>>>> [error]     at 
>>>>> java.base/java.foreign.memory.LayoutType.bytesSize(LayoutType.java:49) 
>>>>>
>>>>> [error]     at 
>>>>> java.base/jdk.internal.foreign.ScopeImpl.allocateInternal(ScopeImpl.java:66)
>>>>> [error]     at 
>>>>> java.base/jdk.internal.foreign.ScopeImpl.allocate(ScopeImpl.java:92)
>>>>> [error]     at 
>>>>> java.base/jdk.internal.foreign.ScopeImpl.allocateStruct(ScopeImpl.java:98)
>>>>> [error]     at TestApp$.delayedEndpoint$TestApp$1(TestApp.scala:22)
>>>>> [error]     at TestApp$delayedInit$body.apply(TestApp.scala:13)
>>>>> [error]     at scala.Function0.apply$mcV$sp(Function0.scala:39)
>>>>> [error]     at scala.Function0.apply$mcV$sp$(Function0.scala:39)
>>>>> [error]     at 
>>>>> scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17) 
>>>>>
>>>>> [error]     at scala.App.$anonfun$main$1$adapted(App.scala:80)
>>>>> [error]     at 
>>>>> scala.collection.immutable.List.foreach(List.scala:392)
>>>>> [error]     at scala.App.main(App.scala:80)
>>>>> [error]     at scala.App.main$(App.scala:78)
>>>>> [error]     at TestApp$.main(TestApp.scala:13)
>>>>> [error]     at TestApp.main(TestApp.scala)
>>>>>
>>>>> Looking at other bugs involving this kind of error message, it 
>>>>> appears that unresolved is a type for when there's not enough 
>>>>> layout information? In any case, here's the struct in question:
>>>>>
>>>>> struct wl_listener {
>>>>>         struct wl_list link;
>>>>>         wl_notify_func_t notify;
>>>>> };
>>>>>
>>>>> and the definition of the elements:
>>>>>
>>>>> typedef void (*wl_notify_func_t)(struct wl_listener *listener, 
>>>>> void *data);
>>>>>
>>>>> struct wl_list {
>>>>>         /** Previous list element */
>>>>>         struct wl_list *prev;
>>>>>         /** Next list element */
>>>>>         struct wl_list *next;
>>>>> };
>>>>>
>>>>> I'm fairly certain the issue lies with the function pointer 
>>>>> notify. When I looked at the decompiled source, wl_notify_func_t 
>>>>> is defined as:
>>>>>
>>>>>     @FunctionalInterface
>>>>>     @NativeCallback("(u64:${wl_listener}u64:v)v")
>>>>>     public interface FI5 {
>>>>>         void fn(Pointer<wayland_server_core.wl_listener> var1, 
>>>>> Pointer<?> var2);
>>>>>     }
>>>>>
>>>>>
>>>>> which seems suspicious to me. var2 should be a Pointer<Void> I 
>>>>> would think. It's a type I see elsewhere in the source for this 
>>>>> file, so it seems suspect that var2 is a Pointer<?>.
>>>>>
>>>>>
>>>>> Is this a bug? Am I just using jextract wrong?
>>>>>
>>>>> Thanks for your help,
>>>>>
>>>>> Mark Hammons
>>>>>