PR python/18285

gdb/ChangeLog:

	PR python/18285
	* NEWS: Document new gdb.XMethodWorker.get_result_type method.
	* eval.c (evaluate_subexp_standard) <OP_FUNCALL>: Handle
	EVAL_AVOID_SIDE_EFFECTS for xmethods.
	* extension-priv.h (struct extension_language_ops)
	<get_xmethod_result_type>: New member.
	* extension.c (get_xmethod_result_type): New function.
	* extension.h (get_xmethod_result_type): Declare.
	* python/py-xmethods.c (get_result_type_method_name): New static
	global.
	(py_get_result_type_method_name): Ditto.
	(gdbpy_get_xmethod_result_type): New function.
	(gdbpy_initialize_xmethods): Initialize py_get_result_type_method_name.
	* python/python-internal.h (gdbpy_get_xmethod_result_type): Declare.
	* python/python.c (python_extension_ops): Add
	gdbpy_get_xmethod_result_type.
	* python/lib/gdb/xmethod.py (XMethodWorker): Add get_result_type.
	* valarith.c (value_x_binop): Handle EVAL_AVOID_SIDE_EFFECTS for
	xmethods.
	(value_x_unop): Ditto.
	* value.c (result_type_of_xmethod): New function.
	* value.h (result_type_of_xmethod): Declare.

gdb/testsuite/ChangeLog:

	* gdb.python/py-xmethods.exp: Add ptype tests.
	* gdb.python/py-xmethods.py (E_method_char_worker): Add
	get_result_type method.

gdb/doc/ChangeLog:

	* python.texi (Xmethod API) <gdb.XMethodWorker.get_result_type>:
	Document.
	(Writing an Xmethod): Add get_result_type to example.

1 files changed, 18 insertions, 2 deletions

diff --git a/gdb/python/lib/gdb/xmethod.py b/gdb/python/lib/gdb/xmethod.py
index 672b2d8..6acc23c 100644
--- a/gdb/python/lib/gdb/xmethod.py
+++ b/gdb/python/lib/gdb/xmethod.py
@@ -101,9 +101,11 @@ class XMethodWorker(object):
     invokes the method when GDB wants it to.  Internally, GDB first invokes the
     'get_arg_types' method to perform overload resolution.  If GDB selects to
     invoke this Python xmethod, then it invokes it via the overridden
-    '__call__' method.
+    '__call__' method.  The 'get_result_type' method is used to implement
+    'ptype' on the xmethod.
 
-    Derived classes should override the 'get_arg_types' and '__call__' methods.
+    Derived classes should override the 'get_arg_types', 'get_result_type'
+    and '__call__' methods.
     """
 
     def get_arg_types(self):
@@ -117,6 +119,20 @@ class XMethodWorker(object):
         """
         raise NotImplementedError("XMethodWorker get_arg_types")
 
+    def get_result_type(self, *args):
+        """Return the type of the result of the xmethod.
+
+        Args:
+            args: Arguments to the method.  Each element of the tuple is a
+                gdb.Value object.  The first element is the 'this' pointer
+                value.  These are the same arguments passed to '__call__'.
+
+        Returns:
+            A gdb.Type object representing the type of the result of the
+            xmethod.
+        """
+        raise NotImplementedError("XMethodWorker get_result_type")
+
     def __call__(self, *args):
         """Invoke the xmethod.