JNI GetObjectArrayElement mark probe ret value shadowed

[Mark Wielaard]

Hi,

In jni.cpp the DT_RETURN_MARK for GetObjectArrayElement tries to capture
the jobject ret value. But the actual ret value returned is a newly
defined jobject ret in the local scope of the if (is_within_bounds)
branch. This means when probing the return of GetObjectArrayElement the
return value always comes as as NULL.

The following trivial patch fixes the issue and makes the actual return
value available to the return probe.

diff -r 6ddec5389232 src/share/vm/prims/jni.cpp
--- a/src/share/vm/prims/jni.cpp	Fri Oct 02 11:26:25 2009 -0700
+++ b/src/share/vm/prims/jni.cpp	Mon Oct 19 21:10:11 2009 +0200
@@ -2116,7 +2116,7 @@
   DT_RETURN_MARK(GetObjectArrayElement, jobject, (const jobject&)ret);
   objArrayOop a = objArrayOop(JNIHandles::resolve_non_null(array));
   if (a->is_within_bounds(index)) {
-    jobject ret = JNIHandles::make_local(env, a->obj_at(index));
+    ret = JNIHandles::make_local(env, a->obj_at(index));
     return ret;
   } else {
     char buf[jintAsStringSize];

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