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, 13 insertions, 1 deletions

diff --git a/gdb/extension-priv.h b/gdb/extension-priv.h
index dd2600ebe8..d0242e28f2 100644
--- a/gdb/extension-priv.h
+++ b/gdb/extension-priv.h
@@ -265,7 +265,7 @@ struct extension_language_ops
   /* xmethod support:
      clone_xmethod_worker_data, free_xmethod_worker_data,
      get_matching_xmethod_workers, get_xmethod_arg_types,
-     invoke_xmethod.
+     get_xmethod_return_type, invoke_xmethod.
      These methods are optional and may be NULL, but if one of them is
      implemented then they all must be.  */
 
@@ -298,6 +298,18 @@ struct extension_language_ops
      int *nargs,
      struct type ***arg_types);
 
+  /* Given a WORKER servicing a particular method, fetch the type of the
+     result of the method.  OBJECT, ARGS, NARGS are the same as for
+     invoke_xmethod.  The result type is stored in *RESULT_TYPE.
+     For backward compatibility with 7.9, which did not support getting the
+     result type, if the get_result_type operation is not provided by WORKER
+     then EXT_LANG_RC_OK is returned and NULL is returned in *RESULT_TYPE.  */
+  enum ext_lang_rc (*get_xmethod_result_type)
+    (const struct extension_language_defn *extlang,
+     struct xmethod_worker *worker,
+     struct value *object, struct value **args, int nargs,
+     struct type **result_type);
+
   /* Invoke the xmethod serviced by WORKER.  The xmethod is invoked
      on OBJECT with arguments in the array ARGS.  NARGS is the length of
      this array.  Returns the value returned by the xmethod.  */