Add xmethod interface to the extension language API.

	* defs.h (enum lval_type): New enumerator "lval_xcallable".
	* extension-priv.h (struct extension_language_ops): Add the
	xmethod interface.
	* extension.c (new_xmethod_worker, clone_xmethod_worker,
	get_matching_xmethod_workers, get_xmethod_argtypes,
	invoke_xmethod, free_xmethod_worker,
	free_xmethod_worker_vec): New functions.
	* extension.h: #include "common/vec.h".
	New function declarations.
	(struct xmethod_worker): New struct.
	(VEC (xmethod_worker_ptr)): New vector type.
	(xmethod_worker_ptr): New typedef.
	(xmethod_worker_vec): Likewise.
	* gdbtypes.c (gdbtypes_post_init): Initialize "xmethod" field of
	builtin_type.
	* gdbtypes.h (enum type_code): New enumerator TYPE_CODE_XMETHOD.
	(struct builtin_type): New field "xmethod".
	* valarith.c (value_ptradd): Assert that the value argument is not
	lval_xcallable.
	* valops.c (value_must_coerce_to_target): Return 0 for
	lval_xcallable values.
	* value.c (struct value): New field XM_WORKER in the field
	LOCATION.
	(value_address, value_raw_address): Return 0 for lval_xcallable
	values.
	(set_value_address): Assert that the value is not an
	lval_xcallable.
	(value_free): Free the associated xmethod worker when freeing
	lval_xcallable values.
	(set_value_component_location): Assert that the WHOLE value is not
	lval_xcallable.
	(value_of_xmethod, call_xmethod): New functions.
	* value.h: Declare "struct xmethod_worker".
	Declare new functions value_of_xmethod, call_xmethod.

1 files changed, 46 insertions, 0 deletions

diff --git a/gdb/extension-priv.h b/gdb/extension-priv.h
index 9e63a9c..9237273 100644
--- a/gdb/extension-priv.h
+++ b/gdb/extension-priv.h
@@ -256,6 +256,52 @@ struct extension_language_ops
      changed or an error occurs no further languages are called.  */
   enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *,
 				     const char *current_gdb_prompt);
+
+  /* xmethod support:
+     clone_xmethod_worker_data, free_xmethod_worker_data,
+     get_matching_xmethod_workers, get_xmethod_arg_types,
+     invoke_xmethod.
+     These methods are optional and may be NULL, but if one of them is
+     implemented then they all must be.  */
+
+  /* Clone DATA and return a new but identical xmethod worker data
+     object for this extension language.  */
+  void * (*clone_xmethod_worker_data)
+    (const struct extension_language_defn *extlang, void *data);
+
+  /* Free the DATA object of this extension language.  */
+  void (*free_xmethod_worker_data)
+    (const struct extension_language_defn *extlang, void *data);
+
+  /* Return a vector of matching xmethod workers defined in this
+     extension language.  The workers service methods with name
+     METHOD_NAME on objects of type OBJ_TYPE.  The vector is returned
+     in DM_VEC.  */
+  enum ext_lang_rc (*get_matching_xmethod_workers)
+    (const struct extension_language_defn *extlang,
+     struct type *obj_type,
+     const char *method_name,
+     xmethod_worker_vec **dm_vec);
+
+  /* Given a WORKER servicing a particular method, return the types
+     of the arguments the method takes.  The number of arguments is
+     returned in NARGS, and their types are returned in the array
+     ARGTYPES.  */
+  enum ext_lang_rc (*get_xmethod_arg_types)
+    (const struct extension_language_defn *extlang,
+     struct xmethod_worker *worker,
+     int *nargs,
+     struct type ***arg_types);
+
+  /* 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.  */
+  struct value * (*invoke_xmethod)
+    (const struct extension_language_defn *extlang,
+     struct xmethod_worker *worker,
+     struct value *object,
+     struct value **args,
+     int nargs);
 };
 
 /* State necessary to restore a signal handler to its previous value.  */