Minor fixes and improvements for svmhelpers.py

Author: dominikmascherbauer

substratevm/src/com.oracle.svm.hosted.image.debug/gdbpy/svmhelpers.py

@@ -414,7 +414,6 @@ def get_rtt(cls, obj: gdb.Value) -> gdb.Type:
                     'J': 'long',
                     'S': 'short',
                 }.get(rtt_name, rtt_name)
-            rtt_name += ' '
             for _ in range(array_dimension):
                 rtt_name += '[]'
 
@@ -775,6 +774,9 @@ def __call__(self, obj: gdb.Value):
 
         # no complex java type -> handle foreign types for selfref checks
         elif obj.type.code == gdb.TYPE_CODE_PTR and obj.type.target().code != gdb.TYPE_CODE_VOID:
+            # Filter out references to the null literal
+            if SVMUtil.is_null(obj):
+                return SVMPPConst(None)
             return self.__call__(obj.dereference())
         elif obj.type.code == gdb.TYPE_CODE_ARRAY:
             return SVMPPArray(obj, False)
@@ -1354,6 +1356,11 @@ def object(self, completion: bool = False) -> str:
                 if this_obj.type.code == gdb.TYPE_CODE_PTR:
                     obj_str = f"{this}->{func_name}"
                 obj_str += f"({param_str})"
+                obj = gdb.parse_and_eval(obj_str)
+                base_obj_str = obj_str
+                if not SVMUtil.is_primitive(obj.type) and SVMUtil.is_java_type(obj.type):
+                    obj, obj_str = SVMCommandPrint.cast_to_rtt(obj, obj_str)
+                self.cache[base_obj_str] = (obj, obj_str)
             elif self.sym == "LBRACK":
                 if (not obj.type.is_array_like) and not isinstance(gdb.default_visualizer(obj), SVMPPArray):
                     raise RuntimeError(f"Array object expected at: {self.expr[:self.t.end]}")