Xmethod support in Python.

	* python/py-xmethods.c: New file.
	* python/py-objfile.c (objfile_object): New field 'xmethods'.
	(objfpy_dealloc): XDECREF on the new xmethods field.
	(objfpy_new, objfile_to_objfile_object): Initialize xmethods
	field.
	(objfpy_get_xmethods): New function.
	(objfile_getset): New entry 'xmethods'.
	* python/py-progspace.c (pspace_object): New field 'xmethods'.
	(pspy_dealloc): XDECREF on the new xmethods field.
	(pspy_new, pspace_to_pspace_object): Initialize	xmethods
	field.
	(pspy_get_xmethods): New function.
	(pspace_getset): New entry 'xmethods'.
	* python/python-internal.h: Add declarations for new functions.
	* python/python.c (_initialize_python): Invoke
	gdbpy_initialize_xmethods.
	* python/lib/gdb/__init__.py (xmethods): New
	attribute.
	* python/lib/gdb/xmethod.py: New file.
	* python/lib/gdb/command/xmethods.py: New file.

	testuite/
	* gdb.python/py-xmethods.cc: New testcase to test xmethods.
	* gdb.python/py-xmethods.exp: New tests to test xmethods.
	* gdb.python/py-xmethods.py: Python script supporting the
	new testcase and tests.

1 files changed, 642 insertions, 0 deletions

diff --git a/gdb/python/py-xmethods.c b/gdb/python/py-xmethods.c
new file mode 100644
index 0000000..0062b2d
--- /dev/null
+++ b/gdb/python/py-xmethods.c
@@ -0,0 +1,642 @@
+/* Support for debug methods in Python.
+
+   Copyright (C) 2013-2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "arch-utils.h"
+#include "extension-priv.h"
+#include "objfiles.h"
+#include "value.h"
+#include "language.h"
+
+#include "python.h"
+#include "python-internal.h"
+
+static const char enabled_field_name[] = "enabled";
+static const char match_method_name[] = "match";
+static const char get_arg_types_method_name[] = "get_arg_types";
+static const char invoke_method_name[] = "invoke";
+static const char matchers_attr_str[] = "xmethods";
+
+static PyObject *py_match_method_name = NULL;
+static PyObject *py_get_arg_types_method_name = NULL;
+static PyObject *py_invoke_method_name = NULL;
+
+struct gdbpy_worker_data
+{
+  PyObject *worker;
+  PyObject *this_type;
+};
+
+static struct xmethod_worker *new_python_xmethod_worker (PyObject *item,
+							 PyObject *py_obj_type);
+
+/* Implementation of free_xmethod_worker_data for Python.  */
+
+void
+gdbpy_free_xmethod_worker_data (const struct extension_language_defn *extlang,
+				void *data)
+{
+  struct gdbpy_worker_data *worker_data = data;
+  struct cleanup *cleanups;
+
+  gdb_assert (worker_data->worker != NULL && worker_data->this_type != NULL);
+
+  /* We don't do much here, but we still need the GIL.  */
+  cleanups = ensure_python_env (get_current_arch (), current_language);
+
+  Py_DECREF (worker_data->worker);
+  Py_DECREF (worker_data->this_type);
+  xfree (worker_data);
+
+  do_cleanups (cleanups);
+}
+
+/* Implementation of clone_xmethod_worker_data for Python.  */
+
+void *
+gdbpy_clone_xmethod_worker_data (const struct extension_language_defn *extlang,
+				 void *data)
+{
+  struct gdbpy_worker_data *worker_data = data, *new_data;
+  struct cleanup *cleanups;
+
+  gdb_assert (worker_data->worker != NULL && worker_data->this_type != NULL);
+
+  /* We don't do much here, but we still need the GIL.  */
+  cleanups = ensure_python_env (get_current_arch (), current_language);
+
+  new_data = XCNEW (struct gdbpy_worker_data);
+  new_data->worker = worker_data->worker;
+  new_data->this_type = worker_data->this_type;
+  Py_INCREF (new_data->worker);
+  Py_INCREF (new_data->this_type);
+
+  do_cleanups (cleanups);
+
+  return new_data;
+}
+
+/* Invoke the "match" method of the MATCHER and return a new reference
+   to the result.  Returns NULL on error.  */
+
+static PyObject *
+invoke_match_method (PyObject *matcher, PyObject *py_obj_type,
+		     const char *xmethod_name)
+{
+  PyObject *py_xmethod_name;
+  PyObject *match_method, *enabled_field, *match_result;
+  struct cleanup *cleanups;
+  int enabled;
+
+  cleanups = make_cleanup (null_cleanup, NULL);
+
+  enabled_field = PyObject_GetAttrString (matcher, enabled_field_name);
+  if (enabled_field == NULL)
+    {
+      do_cleanups (cleanups);
+      return NULL;
+    }
+  make_cleanup_py_decref (enabled_field);
+
+  enabled = PyObject_IsTrue (enabled_field);
+  if (enabled == -1)
+    {
+      do_cleanups (cleanups);
+      return NULL;
+    }
+  if (enabled == 0)
+    {
+      /* Return 'None' if the matcher is not enabled.  */
+      do_cleanups (cleanups);
+      Py_RETURN_NONE;
+    }
+
+  match_method = PyObject_GetAttrString (matcher, match_method_name);
+  if (match_method == NULL)
+    {
+      do_cleanups (cleanups);
+      return NULL;
+    }
+  make_cleanup_py_decref (match_method);
+
+  py_xmethod_name = PyString_FromString (xmethod_name);
+  if (py_xmethod_name == NULL)
+    {
+      do_cleanups (cleanups);
+      return NULL;
+    }
+  make_cleanup_py_decref (py_xmethod_name);
+
+  match_result = PyObject_CallMethodObjArgs (matcher,
+					     py_match_method_name,
+					     py_obj_type,
+					     py_xmethod_name,
+					     NULL);
+
+  do_cleanups (cleanups);
+
+  return match_result;
+}
+
+/* Implementation of get_matching_xmethod_workers for Python.  */
+
+enum ext_lang_rc
+gdbpy_get_matching_xmethod_workers
+  (const struct extension_language_defn *extlang,
+   struct type *obj_type, const char *method_name,
+   xmethod_worker_vec **dm_vec)
+{
+  struct cleanup *cleanups;
+  struct objfile *objfile;
+  VEC (xmethod_worker_ptr) *worker_vec = NULL;
+  PyObject *py_type, *py_progspace;
+  PyObject *py_xmethod_matcher_list = NULL, *list_iter, *matcher;
+
+  gdb_assert (obj_type != NULL && method_name != NULL);
+
+  cleanups = ensure_python_env (get_current_arch (), current_language);
+
+  py_type = type_to_type_object (obj_type);
+  if (py_type == NULL)
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+  make_cleanup_py_decref (py_type);
+
+  /* Create an empty list of debug methods.  */
+  py_xmethod_matcher_list = PyList_New (0);
+  if (py_xmethod_matcher_list == NULL)
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+
+  /* Gather debug method matchers registered with the object files.
+     This could be done differently by iterating over each objfile's matcher
+     list individually, but there's no data yet to show it's needed.  */
+  ALL_OBJFILES (objfile)
+    {
+      PyObject *py_objfile = objfile_to_objfile_object (objfile);
+      PyObject *objfile_matchers, *temp = py_xmethod_matcher_list;
+
+      if (py_objfile == NULL)
+	{
+	  gdbpy_print_stack ();
+	  Py_DECREF (py_xmethod_matcher_list);
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+
+      objfile_matchers = objfpy_get_xmethods (py_objfile, NULL);
+      py_xmethod_matcher_list = PySequence_Concat (temp, objfile_matchers);
+      Py_DECREF (temp);
+      Py_DECREF (objfile_matchers);
+      if (py_xmethod_matcher_list == NULL)
+	{
+	  gdbpy_print_stack ();
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+    }
+
+  /* Gather debug methods matchers registered with the current program
+     space.  */
+  py_progspace = pspace_to_pspace_object (current_program_space);
+  if (py_progspace != NULL)
+    {
+      PyObject *temp = py_xmethod_matcher_list;
+      PyObject *pspace_matchers = pspy_get_xmethods (py_progspace, NULL);
+
+      py_xmethod_matcher_list = PySequence_Concat (temp, pspace_matchers);
+      Py_DECREF (temp);
+      Py_DECREF (pspace_matchers);
+      if (py_xmethod_matcher_list == NULL)
+	{
+	  gdbpy_print_stack ();
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+    }
+  else
+    {
+      gdbpy_print_stack ();
+      Py_DECREF (py_xmethod_matcher_list);
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+
+  /* Gather debug method matchers registered globally.  */
+  if (gdb_python_module != NULL
+      && PyObject_HasAttrString (gdb_python_module, matchers_attr_str))
+    {
+      PyObject *gdb_matchers;
+      PyObject *temp = py_xmethod_matcher_list;
+
+      gdb_matchers = PyObject_GetAttrString (gdb_python_module,
+					     matchers_attr_str);
+      if (gdb_matchers != NULL)
+	{
+	  py_xmethod_matcher_list = PySequence_Concat (temp, gdb_matchers);
+	  Py_DECREF (temp);
+	  Py_DECREF (gdb_matchers);
+	  if (py_xmethod_matcher_list == NULL)
+	    {
+	      gdbpy_print_stack ();
+	      do_cleanups (cleanups);
+
+	      return EXT_LANG_RC_ERROR;
+	    }
+	}
+      else
+	{
+	  gdbpy_print_stack ();
+	  Py_DECREF (py_xmethod_matcher_list);
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+    }
+
+  /* Safe to make a cleanup for py_xmethod_matcher_list now as it
+     will not change any more.  */
+  make_cleanup_py_decref (py_xmethod_matcher_list);
+
+  list_iter = PyObject_GetIter (py_xmethod_matcher_list);
+  if (list_iter == NULL)
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+  while ((matcher = PyIter_Next (list_iter)) != NULL)
+    {
+      PyObject *match_result = invoke_match_method (matcher, py_type,
+						    method_name);
+
+      if (match_result == NULL)
+	{
+	  gdbpy_print_stack ();
+	  Py_DECREF (matcher);
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+      if (match_result == Py_None)
+	; /* This means there was no match.  */
+      else if (PySequence_Check (match_result))
+	{
+	  PyObject *iter = PyObject_GetIter (match_result);
+	  PyObject *py_worker;
+
+	  if (iter == NULL)
+	    {
+	      gdbpy_print_stack ();
+	      Py_DECREF (matcher);
+	      Py_DECREF (match_result);
+	      do_cleanups (cleanups);
+
+	      return EXT_LANG_RC_ERROR;
+	    }
+	  while ((py_worker = PyIter_Next (iter)) != NULL)
+	    {
+	      struct xmethod_worker *worker;
+
+	      worker = new_python_xmethod_worker (py_worker, py_type);
+	      VEC_safe_push (xmethod_worker_ptr, worker_vec, worker);
+	      Py_DECREF (py_worker);
+	    }
+	  Py_DECREF (iter);
+	  /* Report any error that could have occurred while iterating.  */
+	  if (PyErr_Occurred ())
+	    {
+	      gdbpy_print_stack ();
+	      Py_DECREF (matcher);
+	      Py_DECREF (match_result);
+	      do_cleanups (cleanups);
+
+	      return EXT_LANG_RC_ERROR;
+	    }
+	}
+      else
+	{
+	  struct xmethod_worker *worker;
+
+	  worker = new_python_xmethod_worker (match_result, py_type);
+	  VEC_safe_push (xmethod_worker_ptr, worker_vec, worker);
+	}
+
+      Py_DECREF (match_result);
+      Py_DECREF (matcher);
+    }
+  Py_DECREF (list_iter);
+  /* Report any error that could have occurred while iterating.  */
+  if (PyErr_Occurred ())
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+
+  do_cleanups (cleanups);
+  *dm_vec = worker_vec;
+
+  return EXT_LANG_RC_OK;
+}
+
+/* Implementation of get_xmethod_arg_types for Python.  */
+
+enum ext_lang_rc
+gdbpy_get_xmethod_arg_types (const struct extension_language_defn *extlang,
+			     struct xmethod_worker *worker,
+			     int *nargs, struct type ***arg_types)
+{
+  struct gdbpy_worker_data *worker_data = worker->data;
+  PyObject *py_worker = worker_data->worker;
+  PyObject *get_arg_types_method;
+  PyObject *py_argtype_list, *list_iter = NULL, *item;
+  struct cleanup *cleanups;
+  struct type **type_array, *obj_type;
+  int i = 1, arg_count;
+
+  /* Set nargs to -1 so that any premature return from this function returns
+     an invalid/unusable number of arg types.  */
+  *nargs = -1;
+
+  cleanups = ensure_python_env (get_current_arch (), current_language);
+
+  get_arg_types_method =  PyObject_GetAttrString (py_worker,
+						  get_arg_types_method_name);
+  if (get_arg_types_method == NULL)
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+  make_cleanup_py_decref (get_arg_types_method);
+
+  py_argtype_list = PyObject_CallMethodObjArgs (py_worker,
+						py_get_arg_types_method_name,
+						NULL);
+  if (py_argtype_list == NULL)
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+
+      return EXT_LANG_RC_ERROR;
+    }
+  make_cleanup_py_decref (py_argtype_list);
+  if (py_argtype_list == Py_None)
+    arg_count = 0;
+  else if (PySequence_Check (py_argtype_list))
+    {
+      arg_count = PySequence_Size (py_argtype_list);
+      if (arg_count == -1)
+	{
+	  gdbpy_print_stack ();
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+
+      list_iter = PyObject_GetIter (py_argtype_list);
+      if (list_iter == NULL)
+	{
+	  gdbpy_print_stack ();
+	  do_cleanups (cleanups);
+
+	  return EXT_LANG_RC_ERROR;
+	}
+      make_cleanup_py_decref (list_iter);
+    }
+  else
+    arg_count = 1;
+
+  /* Include the 'this' argument in the size.  */
+  type_array = XCNEWVEC (struct type *, arg_count + 1);
+  i = 1;
+  if (list_iter != NULL)
+    {
+      while ((item = PyIter_Next (list_iter)) != NULL)
+	{
+	  struct type *arg_type = type_object_to_type (item);
+
+	  Py_DECREF (item);
+	  if (arg_type == NULL)
+	    {
+	      PyErr_SetString (PyExc_TypeError,
+			       _("Arg type returned by the get_arg_types "
+				 "method of a debug method worker object is "
+				 "not a gdb.Type object."));
+	      break;
+	    }
+
+	  type_array[i] = arg_type;
+	  i++;
+	}
+    }
+  else if (arg_count == 1)
+    {
+      /* py_argtype_list is not actually a list but a single gdb.Type
+	 object.  */
+      struct type *arg_type = type_object_to_type (py_argtype_list);
+
+      if (arg_type == NULL)
+	{
+	  PyErr_SetString (PyExc_TypeError,
+			   _("Arg type returned by the get_arg_types method "
+			     "of an xmethod worker object is not a gdb.Type "
+			     "object."));
+	}
+      else
+	{
+	  type_array[i] = arg_type;
+	  i++;
+	}
+    }
+  if (PyErr_Occurred ())
+    {
+      gdbpy_print_stack ();
+      do_cleanups (cleanups);
+      xfree (type_array);
+
+      return EXT_LANG_RC_ERROR;
+    }
+
+  /* Add the type of 'this' as the first argument.  The 'this' pointer should
+     be a 'const' value.  Hence, create a 'const' variant of the 'this' pointer
+     type.  */
+  obj_type = type_object_to_type (worker_data->this_type);
+  type_array[0] = make_cv_type (1, 0, lookup_pointer_type (obj_type), NULL);
+  *nargs = i;
+  *arg_types = type_array;
+  do_cleanups (cleanups);
+
+  return EXT_LANG_RC_OK;
+}
+
+/* Implementation of invoke_xmethod for Python.  */
+
+struct value *
+gdbpy_invoke_xmethod (const struct extension_language_defn *extlang,
+		      struct xmethod_worker *worker,
+		      struct value *obj, struct value **args, int nargs)
+{
+  int i;
+  struct cleanup *cleanups;
+  PyObject *py_value_obj, *py_arg_tuple, *py_result;
+  struct type *obj_type, *this_type;
+  struct value *res = NULL;
+  struct gdbpy_worker_data *worker_data = worker->data;
+  PyObject *xmethod_worker = worker_data->worker;
+
+  cleanups = ensure_python_env (get_current_arch (), current_language);
+
+  obj_type = check_typedef (value_type (obj));
+  this_type = check_typedef (type_object_to_type (worker_data->this_type));
+  if (TYPE_CODE (obj_type) == TYPE_CODE_PTR)
+    {
+      struct type *this_ptr = lookup_pointer_type (this_type);
+
+      if (!types_equal (obj_type, this_ptr))
+	obj = value_cast (this_ptr, obj);
+    }
+  else if (TYPE_CODE (obj_type) == TYPE_CODE_REF)
+    {
+      struct type *this_ref = lookup_reference_type (this_type);
+
+      if (!types_equal (obj_type, this_ref))
+	obj = value_cast (this_ref, obj);
+    }
+  else
+    {
+      if (!types_equal (obj_type, this_type))
+	obj = value_cast (this_type, obj);
+    }
+  py_value_obj = value_to_value_object (obj);
+  if (py_value_obj == NULL)
+    {
+      gdbpy_print_stack ();
+      error (_("Error while executing Python code."));
+    }
+  make_cleanup_py_decref (py_value_obj);
+
+  py_arg_tuple = PyTuple_New (nargs + 1);
+  if (py_arg_tuple == NULL)
+    {
+      gdbpy_print_stack ();
+      error (_("Error while executing Python code."));
+    }
+  make_cleanup_py_decref (py_arg_tuple);
+
+  /* PyTuple_SET_ITEM steals the reference of the element.  Hence INCREF the
+     reference to the 'this' object as we have a cleanup to DECREF it.  */
+  Py_INCREF (py_value_obj);
+  PyTuple_SET_ITEM (py_arg_tuple, 0, py_value_obj);
+
+  for (i = 0; i < nargs; i++)
+    {
+      PyObject *py_value_arg = value_to_value_object (args[i]);
+
+      if (py_value_arg == NULL)
+	{
+	  gdbpy_print_stack ();
+	  error (_("Error while executing Python code."));
+	}
+
+      PyTuple_SET_ITEM (py_arg_tuple, i + 1, py_value_arg);
+    }
+
+  py_result = PyObject_CallObject (xmethod_worker, py_arg_tuple);
+  if (py_result == NULL)
+    {
+      gdbpy_print_stack ();
+      error (_("Error while executing Python code."));
+    }
+  make_cleanup_py_decref (py_result);
+
+  if (py_result != Py_None)
+    {
+      res = convert_value_from_python (py_result);
+      if (res == NULL)
+	{
+	  gdbpy_print_stack ();
+	  error (_("Error while executing Python code."));
+	}
+    }
+  else
+    {
+      res = allocate_value (lookup_typename (python_language, python_gdbarch,
+					     "void", NULL, 0));
+    }
+
+  do_cleanups (cleanups);
+
+  return res;
+}
+
+/* Creates a new Python xmethod_worker object.
+   The new object has data of type 'struct gdbpy_worker_data' composed
+   with the components PY_WORKER and THIS_TYPE.  */
+
+static struct xmethod_worker *
+new_python_xmethod_worker (PyObject *py_worker, PyObject *this_type)
+{
+  struct gdbpy_worker_data *data;
+
+  gdb_assert (py_worker != NULL && this_type != NULL);
+
+  data = XCNEW (struct gdbpy_worker_data);
+  data->worker = py_worker;
+  data->this_type = this_type;
+  Py_INCREF (py_worker);
+  Py_INCREF (this_type);
+
+  return new_xmethod_worker (&extension_language_python, data);
+}
+
+int
+gdbpy_initialize_xmethods (void)
+{
+  py_match_method_name = PyString_FromString (match_method_name);
+  if (py_match_method_name == NULL)
+    return -1;
+
+  py_invoke_method_name = PyString_FromString (invoke_method_name);
+  if (py_invoke_method_name == NULL)
+    return -1;
+
+  py_get_arg_types_method_name
+    = PyString_FromString (get_arg_types_method_name);
+  if (py_get_arg_types_method_name == NULL)
+    return -1;
+
+  return 1;
+}