JNI DEFINE_NEWSCALARARRAY uses DT_RETURN_MARK_DECL_FOR

[Keith McGuigan]

Thank you for these fixes, Mark, I've integrated them into 
http://hg.openjdk.java.net/jdk7/hotspot-rt/hotspot and they'll bubble up 
to the other repos (hotspot/hotspot and jdk7/hotspot) soon.

Please refer to CR 6893483 to track these fixes.

--
- Keith

Mark Wielaard wrote:
> Hi,
> 
> In jni.cpp the DEFINE_NEWSCALARARRAY macro uses DT_RETURN_MARK_DECL_FOR
> instead of the normal DT_RETURN_MARK_DECL. The DT_RETURN_MARK_DECL_FOR
> macro should only be used for mark probes that could return a primitive
> jfloat or jdouble. But DEFINE_NEWSCALARARRAY creates the functions for
> New<Type>Array which return primitiveTypeArrays. This means that for
> NewFloatArray and NewDoubleArray you cannot get the return value in the
> return mark probe.
> 
> According to hotspot_jni.d the intention is to return these values in
> those cases:
> 
>   probe NewDoubleArray__entry(void*, uintptr_t);
>   probe NewDoubleArray__return(void*);
>   probe NewFloatArray__entry(void*, uintptr_t);
>   probe NewFloatArray__return(void*);
> 
> The attached trivial patch fixes it and makes the actual return value in
> those cases available.
> 
> Tested against Systemtap, but the same should work for DTrace also.
> I don't have access to a system with solaris/dtrace on it, so it would
> be nice of someone who does could double check the above on such a
> system.
> 
> Please let me know if I should create a bug also on
> https://bugs.openjdk.java.net/ and/or if I should report/post this patch
> on some other mailing-list.
> 
> Thanks,
> 
> Mark
>