Panama unresolved error when instantiating wayland struct...

[Maurizio Cimadamore]

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
>>>