Fix converting a remote PyStringObject to a local string

Cython/Debugger/libcython.py

@@ -244,13 +244,8 @@ class CythonBase(object):
             if not pyframeobject:
                 raise gdb.GdbError('Unable to read information on python frame')
 
-            try:
-                filename = pyframeobject.filename()
-            except RuntimeError:
-                filename = None
-                lineno = None
-            else:
-                lineno = pyframeobject.current_line_num()
+            filename = pyframeobject.filename()
+            lineno = pyframeobject.current_line_num()
             
             if pygments:
                 lexer = pygments.lexers.PythonLexer(stripall=False)
@@ -313,10 +308,7 @@ class CythonBase(object):
                 # print this python function as a C function
                 return self.print_stackframe(frame, index, is_c=True)
             
-            try:
-                func_name = str(pyframe.co_name)
-            except RuntimeError:
-                func_name = 'Unknown Function Name'
+            func_name = pyframe.co_name
             func_cname = 'PyEval_EvalFrameEx'
             func_args = []
         elif self.is_cython_function(frame):

Cython/Debugger/libpython.py

@@ -975,7 +975,9 @@ class PyStringObjectPtr(PyObjectPtr):
     def __str__(self):
         field_ob_size = self.field('ob_size')
         field_ob_sval = self.field('ob_sval')
-        char_ptr = field_ob_sval.address.cast(_type_unsigned_char_ptr)
+        char_ptr = field_ob_sval.address.cast(
+            gdb.lookup_type('char').pointer())
+        
         return ''.join([chr(char_ptr[i]) for i in safe_range(field_ob_size)])
 
     def proxyval(self, visited):