_Py_PrintReferences(): Changed to print object address at start of each

new line.

New pvt API function _Py_PrintReferenceAddresses():  Prints only the
addresses and refcnts of the live objects.  This is always safe to call,
because it has no dependence on Python's C API.

Py_Finalize():  If envar PYTHONDUMPREFS is set, call (the new)
_Py_PrintReferenceAddresses() right before dumping final pymalloc stats.
We can't print the reprs of the objects here because too much of the
interpreter has been shut down.  You need to correlate the addresses
displayed here with the object reprs printed by the earlier
PYTHONDUMPREFS call to _Py_PrintReferences().

Include/object.h

@@ -582,6 +582,7 @@ PyAPI_FUNC(void) _Py_NewReference(PyObject *);
 PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
 PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
 PyAPI_FUNC(void) _Py_PrintReferences(FILE *);
+PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *);
 PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force);
 
 #else

Objects/object.c

@@ -2022,19 +2022,34 @@ _Py_Dealloc(PyObject *op)
 	(*dealloc)(op);
 }
 
+/* Print all live objects.  Because PyObject_Print is called, the
+ * interpreter must be in a healthy state.
+ */
 void
 _Py_PrintReferences(FILE *fp)
 {
 	PyObject *op;
 	fprintf(fp, "Remaining objects:\n");
 	for (op = refchain._ob_next; op != &refchain; op = op->_ob_next) {
-		fprintf(fp, "[%d] ", op->ob_refcnt);
+		fprintf(fp, "%p [%d] ", op, op->ob_refcnt);
 		if (PyObject_Print(op, fp, 0) != 0)
 			PyErr_Clear();
 		putc('\n', fp);
 	}
 }
 
+/* Print the addresses of all live objects.  Unlike _Py_PrintReferences, this
+ * doesn't make any calls to the Python C API, so is always safe to call.
+ */
+void
+_Py_PrintReferenceAddresses(FILE *fp)
+{
+	PyObject *op;
+	fprintf(fp, "Remaining object addresses:\n");
+	for (op = refchain._ob_next; op != &refchain; op = op->_ob_next)
+		fprintf(fp, "%p [%d]\n", op, op->ob_refcnt);
+}
+
 PyObject *
 _Py_GetObjects(PyObject *self, PyObject *args)
 {

Python/pythonrun.c

@@ -284,9 +284,8 @@ Py_Finalize(void)
 	 * Alas, a lot of stuff may still be alive now that will be cleaned
 	 * up later.
 	 */
-	if (Py_GETENV("PYTHONDUMPREFS")) {
+	if (Py_GETENV("PYTHONDUMPREFS"))
 		_Py_PrintReferences(stderr);
-	}
 #endif /* Py_TRACE_REFS */
 
 	/* Now we decref the exception classes.  After this point nothing
@@ -325,6 +324,14 @@ Py_Finalize(void)
 
 	PyGrammar_RemoveAccelerators(&_PyParser_Grammar);
 
+#ifdef Py_TRACE_REFS
+	/* Display addresses (& refcnts) of all objects still alive.
+	 * An address can be used to find the repr of the object, printed
+	 * above by _Py_PrintReferences.
+	 */
+	if (Py_GETENV("PYTHONDUMPREFS"))
+		_Py_PrintReferenceAddresses(stderr);
+#endif /* Py_TRACE_REFS */
 #ifdef PYMALLOC_DEBUG
 	if (Py_GETENV("PYTHONMALLOCSTATS"))
 		_PyObject_DebugMallocStats();