perf/scripts: Tuple was set from long in both branches in python_proc…

…ess_event()

This is a fix to the signed/unsigned field handling in the
Python scripting engine, based on a patch from Roel Kluin.

Basically, Python wants to use a PyInt (which is internally a
long) if it can i.e. if the value will fit into that type.  If
not, it stores it into a PyLong, which isn't actually a long,
but an arbitrary-precision integer variable.

The code below is similar to to what Python does internally, and
it seems to work as expected on the x86 and x86_64 sytems I
tested it on.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Roel Kluin <roel.kluin@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: rostedt@goodmis.org
LKML-Reference: <1270184305.6422.10.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/scripting-engines/trace-event-python.c

@@ -208,7 +208,7 @@ static void python_process_event(int cpu, void *data,
 				 int size __unused,
 				 unsigned long long nsecs, char *comm)
 {
-	PyObject *handler, *retval, *context, *t;
+	PyObject *handler, *retval, *context, *t, *obj;
 	static char handler_name[256];
 	struct format_field *field;
 	unsigned long long val;
@@ -256,16 +256,23 @@ static void python_process_event(int cpu, void *data,
 				offset &= 0xffff;
 			} else
 				offset = field->offset;
-			PyTuple_SetItem(t, n++,
-				PyString_FromString((char *)data + offset));
+			obj = PyString_FromString((char *)data + offset);
 		} else { /* FIELD_IS_NUMERIC */
 			val = read_size(data + field->offset, field->size);
 			if (field->flags & FIELD_IS_SIGNED) {
-				PyTuple_SetItem(t, n++, PyInt_FromLong(val));
+				if ((long long)val >= LONG_MIN &&
+				    (long long)val <= LONG_MAX)
+					obj = PyInt_FromLong(val);
+				else
+					obj = PyLong_FromLongLong(val);
 			} else {
-				PyTuple_SetItem(t, n++, PyInt_FromLong(val));
+				if (val <= LONG_MAX)
+					obj = PyInt_FromLong(val);
+				else
+					obj = PyLong_FromUnsignedLongLong(val);
 			}
 		}
+		PyTuple_SetItem(t, n++, obj);
 	}
 
 	if (_PyTuple_Resize(&t, n) == -1)