[Bug java/18278] New: JNI functions cannot return a weak reference

[Bug java/18278] New: JNI functions cannot return a weak reference

[laurent at bearteam dot org]

If a JNI function returns a weak reference created with NewWeakGlobalRef, you'll
get a class cast exception like this:

java.lang.ClassCastException: gnu.gcj.runtime.JNIWeakRef cannot be cast to
org.gnu.glib.GObject
   at _Jv_CheckCast (/usr/lib/libgcj.so.6.0.0)

-- 
           Summary: JNI functions cannot return a weak reference
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: java
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: laurent at bearteam dot org
                CC: gcc-bugs at gcc dot gnu dot org,java-prs at gcc dot gnu
                    dot org
 GCC build triplet: i486-pc-linux-gnu
  GCC host triplet: i486-pc-linux-gnu
GCC target triplet: i486-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Additional Comments From tromey at gcc dot gnu dot org  2004-11-02 18:55 -------
Do you have some sample code or something?
I tend to suspect your code, simply for the reason
that GObject is not part of libgcj.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[laurent at bearteam dot org]

------- Additional Comments From laurent at bearteam dot org  2004-11-02 20:09 -------
(In reply to comment #1)
> Do you have some sample code or something?
> I tend to suspect your code, simply for the reason
> that GObject is not part of libgcj.

I should have mentionned that GObject is the class I try to cast the returned
weak local reference created in the JNI code to. I'll attach a sample code very
soon.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[laurent at bearteam dot org]

------- Additional Comments From laurent at bearteam dot org  2004-11-02 20:34 -------
Created an attachment (id=7460)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7460&action=view)
Sample JNI c code

This is jni.i.gz, as produced by:

cc -c -save-temps weakref.c -o weakref.o
gzip weakref.i


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[laurent at bearteam dot org]

------- Additional Comments From laurent at bearteam dot org  2004-11-02 20:38 -------
Created an attachment (id=7461)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7461&action=view)
Sample java code

Here's how I compiled to whole thing:

cc -c  weakref.c -o weakref.o
cc -shared  -Xlinker --no-undefined weakref.o -o libweakref.so
gcj -o JNIWeakRef --main=JNIWeakRef -L . -l weakref -fjni JNIWeakRef.java

And then run with like this:

laurent@stan:~/tmp/gc$ LD_LIBRARY_PATH=. ./JNIWeakRef 
Exception in thread "main" java.lang.ClassCastException:
gnu.gcj.runtime.JNIWeakRef cannot be cast to JNIWeakRef
   at _Jv_CheckCast (/usr/lib/libgcj.so.6.0.0)
   at JNIWeakRef.main(java.lang.String[]) (Unknown Source)

Sun's JVM (1.4.2) has no problem with it.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Additional Comments From tromey at gcc dot gnu dot org  2004-12-01 21:40 -------
How curious.  Apparently the JDK unwraps the return result of
a JNI method that returns a JNI weak reference.

I think it is too late to implement this for GCC 4.0 (unless the
commit rules change again).  Here is how it could be fixed:

* Write a new _Jv_UnwrapJNIWeakReference function in jni.cc that is
  extern "C".  (This can be copied from the existing 'unwrap'
  template function.)
* Make a built-in declaration for this in gcj
* Change expr.c:build_jni_stub to call this function when the return
  type is not a primitive type.  (there is already a comment explaining
  where some unwrapping could be done)
* Also modify jni.cc:_Jv_JNIMethod::call() to do this transformation


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-02 13:36 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-12-02 13:36:47
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Comment #7 from tromey at gcc dot gnu dot org  2005-11-28 20:06 -------
I'm handling this


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |tromey at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-06-04 16:42:21         |2005-11-28 20:06:24
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Comment #8 from tromey at gcc dot gnu dot org  2005-11-29 18:35 -------
Subject: Bug 18278

Author: tromey
Date: Tue Nov 29 18:34:58 2005
New Revision: 107676

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107676
Log:
gcc/java:
        PR java/18278:
        * expr.c (build_jni_stub): Unwrap the return value.
        * java-tree.h (soft_unwrapjni_node): New define.
        (enum java_tree_index): Added JTI_SOFT_UNWRAPJNI_NODE.
        * decl.c (java_init_decl_processing): Initialize
        soft_unwrapjni_node.
libjava:
        PR java/18278:
        * testsuite/libjava.jni/pr18278.out: New file.
        * testsuite/libjava.jni/pr18278.c: New file.
        * testsuite/libjava.jni/pr18278.java: New file.
        * include/jvm.h (_Jv_UnwrapJNIweakReference): Declare.
        * jni.cc (_Jv_UnwrapJNIweakReference): New function.
        (call): Unwrap return value if needed.

Added:
    trunk/libjava/testsuite/libjava.jni/pr18278.c
    trunk/libjava/testsuite/libjava.jni/pr18278.java
    trunk/libjava/testsuite/libjava.jni/pr18278.out
Modified:
    trunk/gcc/java/ChangeLog
    trunk/gcc/java/decl.c
    trunk/gcc/java/expr.c
    trunk/gcc/java/java-tree.h
    trunk/libjava/ChangeLog
    trunk/libjava/include/jvm.h
    trunk/libjava/jni.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Comment #9 from tromey at gcc dot gnu dot org  2005-11-29 18:58 -------
Subject: Bug 18278

Author: tromey
Date: Tue Nov 29 18:58:23 2005
New Revision: 107677

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107677
Log:
gcc/java:
        PR java/18278:
        * expr.c (build_jni_stub): Unwrap the return value.
        * java-tree.h (soft_unwrapjni_node): New define.
        (enum java_tree_index): Added JTI_SOFT_UNWRAPJNI_NODE.
        * decl.c (java_init_decl_processing): Initialize
        soft_unwrapjni_node.
libjava:
        PR java/18278:
        * testsuite/libjava.jni/pr18278.out: New file.
        * testsuite/libjava.jni/pr18278.c: New file.
        * testsuite/libjava.jni/pr18278.java: New file.
        * include/jvm.h (_Jv_UnwrapJNIweakReference): Declare.
        * jni.cc (_Jv_UnwrapJNIweakReference): New function.
        (call): Unwrap return value if needed.

Added:
    branches/gcc-4_1-branch/libjava/testsuite/libjava.jni/pr18278.c
    branches/gcc-4_1-branch/libjava/testsuite/libjava.jni/pr18278.java
    branches/gcc-4_1-branch/libjava/testsuite/libjava.jni/pr18278.out
Modified:
    branches/gcc-4_1-branch/gcc/java/ChangeLog
    branches/gcc-4_1-branch/gcc/java/decl.c
    branches/gcc-4_1-branch/gcc/java/expr.c
    branches/gcc-4_1-branch/gcc/java/java-tree.h
    branches/gcc-4_1-branch/libjava/ChangeLog
    branches/gcc-4_1-branch/libjava/include/jvm.h
    branches/gcc-4_1-branch/libjava/jni.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Comment #10 from tromey at gcc dot gnu dot org  2005-11-29 21:14 -------
Fix checked in.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

------- Comment #11 from tromey at gcc dot gnu dot org  2005-12-06 02:13 -------
Subject: Bug 18278

Author: tromey
Date: Tue Dec  6 02:13:54 2005
New Revision: 108096

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=108096
Log:
gcc/java
        PR java/18278:
        * expr.c (build_jni_stub): Unwrap the return value.
        * java-tree.h (soft_unwrapjni_node): New define.
        (enum java_tree_index): Added JTI_SOFT_UNWRAPJNI_NODE.
        * decl.c (java_init_decl_processing): Initialize
        soft_unwrapjni_node.
libjava:
        PR java/18278:
        * testsuite/libjava.jni/pr18278.out: New file.
        * testsuite/libjava.jni/pr18278.c: New file.
        * testsuite/libjava.jni/pr18278.java: New file.
        * include/jvm.h (_Jv_UnwrapJNIweakReference): Declare.
        * jni.cc (_Jv_UnwrapJNIweakReference): New function.
        (call): Unwrap return value if needed.

Added:
    branches/gcc-4_0-branch/libjava/testsuite/libjava.jni/pr18278.c
    branches/gcc-4_0-branch/libjava/testsuite/libjava.jni/pr18278.java
    branches/gcc-4_0-branch/libjava/testsuite/libjava.jni/pr18278.out
Modified:
    branches/gcc-4_0-branch/gcc/java/ChangeLog
    branches/gcc-4_0-branch/gcc/java/decl.c
    branches/gcc-4_0-branch/gcc/java/expr.c
    branches/gcc-4_0-branch/gcc/java/java-tree.h
    branches/gcc-4_0-branch/libjava/ChangeLog
    branches/gcc-4_0-branch/libjava/include/jvm.h
    branches/gcc-4_0-branch/libjava/jni.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278

[Bug java/18278] JNI functions cannot return a weak reference

[tromey at gcc dot gnu dot org]

-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.1.0                       |4.0.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18278