JVMTI stack tracing patch breaks C++ ABI

Wed Sep 19 21:31:00 GMT 2007

Keith Seitz wrote:
> Hi,
>> Mark discovered today that the following JDWP patch:
>> 2007年01月29日 Kyle Galloway <kgallowa@redhat.com>
>> * include/java-interp.h: Added _Jv_Frame class and its two
> subclasses _Jv_InterpFrame and _Jv_NativeFrame. Also moved
> _Jv_FrameType from java-stack.h.
> * include/java-stack.h: Removed _Jv_FrameType.
> --> * java/lang/Thread.java: Added frame member to hold new
> composite frame stack.
> * java/lang/Thread.h: Regenerated.
> * java/lang/Thread.class: Rebuilt.
> * jni.cc (_Jv_JNIMethod::call): Push a frame onto the stack when
> calling a JNI method.
> * jvmti.cc (_Jv_JVMTI_GetStackTrace): New Method.
> (_Jv_JVMTI_GetFrameCount): New method.
> * stacktrace.cc (UnwindTraceFn): Modified to use new _Jv_Frame
> classes.
> * testsuite/libjava.jvmti/interp/getstacktrace.jar: New test.
> * testsuite/libjava.jvmti/interp/natgetstacktrace.cc: New test.
> * testsuite/libjava.jvmti/interp/getstacktrace.h: New test.
> * testsuite/libjava.jvmti/interp/getstacktrace.jar: New test.
> * testsuite/libjava.jvmti/interp/getstacktrace.out: Output file
> for test.
>> breaks the C++ ABI by adding a new field to Thread.java. So I presume 
> this should be fixed?

I don't think so. There is no C++ ABI compatibility across GCC 
releases. This should be fine as is.
If you want compatibility, use indirect dispatch.
>> Does adding something to struct natThread to do this sound like a 
> reasonable plan? Or we could simply hold around a hashtable which maps 
> java.lang.Thread to their corresponding frame pointers.

N/A I think. See above.
David Daney