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.

gdb/ChangeLog

@@ -1,3 +1,26 @@
+2014-06-03  Siva Chandra Reddy  <sivachandra@google.com>
+
+	* 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.
+
 2014-06-03  Siva Chandra Reddy  <sivachandra@google.com>
 
 	* eval.c (evaluate_subexp_standard): Call the xmethod if the

gdb/Makefile.in

@@ -350,6 +350,7 @@ SUBDIR_PYTHON_OBS = \
 	py-breakpoint.o \
 	py-cmd.o \
 	py-continueevent.o \
+	py-xmethods.o \
 	py-event.o \
 	py-evtregistry.o \
 	py-evts.o \
@@ -386,6 +387,7 @@ SUBDIR_PYTHON_SRCS = \
 	python/py-breakpoint.c \
 	python/py-cmd.c \
 	python/py-continueevent.c \
+	python/py-xmethods.c \
 	python/py-event.c \
 	python/py-evtregistry.c \
 	python/py-evts.c \
@@ -2396,6 +2398,10 @@ py-continueevent.o: $(srcdir)/python/py-continueevent.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-continueevent.c
 	$(POSTCOMPILE)
 
+py-xmethods.o: $(srcdir)/python/py-xmethods.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-xmethods.c
+	$(POSTCOMPILE)
+
 py-event.o: $(srcdir)/python/py-event.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-event.c
 	$(POSTCOMPILE)

gdb/data-directory/Makefile.in

@@ -63,8 +63,10 @@ PYTHON_FILES = \
 	gdb/types.py \
 	gdb/printing.py \
 	gdb/prompt.py \
+	gdb/xmethod.py \
 	gdb/command/bound_registers.py \
 	gdb/command/__init__.py \
+	gdb/command/xmethods.py \
 	gdb/command/frame_filters.py \
 	gdb/command/type_printers.py \
 	gdb/command/pretty_printers.py \

gdb/python/lib/gdb/__init__.py

@@ -67,6 +67,8 @@ pretty_printers = []
 
 # Initial type printers.
 type_printers = []
+# Initial xmethod matchers.
+xmethods = []
 # Initial frame filters.
 frame_filters = {}
 

gdb/python/lib/gdb/command/xmethods.py

@@ -0,0 +1,272 @@
+# Xmethod commands.
+# Copyright 2013-2014 Free Software Foundation, Inc.
+
+# 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/>.
+
+import gdb
+import re
+
+"""GDB commands for working with xmethods."""
+
+
+def validate_xm_regexp(part_name, regexp):
+    try:
+        return re.compile(regexp)
+    except SyntaxError:
+        raise SyntaxError("Invalid %s regexp: %s", part_name, regexp)
+
+
+def parse_xm_command_args(arg):
+    """Parses the arguments passed to a xmethod command.
+
+    Arguments:
+        arg: The argument string passed to a xmethod command.
+
+    Returns:
+        A 3-tuple: (<locus matching regular expression>,
+                    <matcher matching regular expression>,
+                    <name matching regular experession>)
+    """
+    argv = gdb.string_to_argv(arg)
+    argc = len(argv)
+    if argc > 2:
+        raise SyntaxError("Too many arguments to command.")
+    locus_regexp = ""
+    matcher_name_regexp = ""
+    xm_name_regexp = None
+    if argc >= 1:
+        locus_regexp = argv[0]
+    if argc == 2:
+        parts = argv[1].split(";", 1)
+        matcher_name_regexp = parts[0]
+        if len(parts) > 1:
+            xm_name_regexp = parts[1]
+    if xm_name_regexp:
+        name_re = validate_xm_regexp("xmethod name", xm_name_regexp)
+    else:
+        name_re = None
+    return (validate_xm_regexp("locus", locus_regexp),
+            validate_xm_regexp("matcher name", matcher_name_regexp),
+            name_re)
+
+
+def get_global_method_matchers(locus_re, matcher_re):
+    """Returns a dict of matching globally registered xmethods.
+
+    Arguments:
+        locus_re: Even though only globally registered xmethods are
+                  looked up, they will be looked up only if 'global' matches
+                  LOCUS_RE.
+        matcher_re: The regular expression matching the names of xmethods.
+
+    Returns:
+        A dict of matching globally registered xmethod matchers.  The only
+        key in the dict will be 'global'.
+    """
+    locus_str = "global"
+    xm_dict = { locus_str: [] }
+    if locus_re.match("global"):
+        xm_dict[locus_str].extend(
+            [m for m in gdb.xmethods if matcher_re.match(m.name)])
+    return xm_dict
+
+
+def get_method_matchers_in_loci(loci, locus_re, matcher_re):
+    """Returns a dict of matching registered xmethods in the LOCI.
+
+    Arguments:
+        loci: The list of loci to lookup matching xmethods in.
+        locus_re: Xmethod matchers will be looked up in a particular locus
+                  only if its filename matches the regular expression LOCUS_RE.
+        matcher_re: The regular expression to match the xmethod matcher
+                    names.
+
+    Returns:
+        A dict of matching xmethod matchers.  The keys of the dict are the
+        filenames of the loci the xmethod matchers belong to.
+    """
+    xm_dict = {}
+    for locus in loci:
+        if isinstance(locus, gdb.Progspace):
+            if (not locus_re.match(locus.filename) and
+                not locus_re.match('progspace')):
+                continue
+            locus_type = "progspace"
+        else:
+            if not locus_re.match(locus.filename):
+                continue
+            locus_type = "objfile"
+        locus_str = "%s %s" % (locus_type, locus.filename)
+        xm_dict[locus_str] = [
+            m for m in locus.xmethods if matcher_re.match(m.name)]
+    return xm_dict
+
+
+def print_xm_info(xm_dict, name_re):
+    """Print a dictionary of xmethods."""
+    def get_status_string(method):
+        if not m.enabled:
+            return " [disabled]"
+        else:
+          return ""
+
+    if not xm_dict:
+        return
+    for locus_str in xm_dict:
+        if not xm_dict[locus_str]:
+            continue
+        print ("Xmethods in %s:" % locus_str)
+        for matcher in xm_dict[locus_str]:
+            print ("  %s" % matcher.name)
+            if not matcher.methods:
+                continue
+            for m in matcher.methods:
+                if name_re is None or name_re.match(m.name):
+                    print ("    %s%s" % (m.name, get_status_string(m)))
+
+
+def set_xm_status1(xm_dict, name_re, status):
+    """Set the status (enabled/disabled) of a dictionary of xmethods."""
+    for locus_str, matchers in xm_dict.iteritems():
+        for matcher in matchers:
+            if not name_re:
+                # If the name regex is missing, then set the status of the
+                # matcher and move on.
+                matcher.enabled = status
+                continue
+            if not matcher.methods:
+                # The methods attribute could be None.  Move on.
+                continue
+            for m in matcher.methods:
+                if name_re.match(m.name):
+                    m.enabled = status
+
+
+def set_xm_status(arg, status):
+    """Set the status (enabled/disabled) of xmethods matching ARG.
+    This is a helper function for enable/disable commands.  ARG is the
+    argument string passed to the commands.
+    """
+    locus_re, matcher_re, name_re = parse_xm_command_args(arg)
+    set_xm_status1(get_global_method_matchers(locus_re, matcher_re), name_re,
+                   status)
+    set_xm_status1(
+        get_method_matchers_in_loci(
+            [gdb.current_progspace()], locus_re, matcher_re),
+        name_re,
+        status)
+    set_xm_status1(
+        get_method_matchers_in_loci(gdb.objfiles(), locus_re, matcher_re),
+        name_re,
+        status)
+
+
+class InfoXMethod(gdb.Command):
+    """GDB command to list registered xmethod matchers.
+
+    Usage: info xmethod [locus-regexp [name-regexp]]
+
+    LOCUS-REGEXP is a regular expression matching the location of the
+    xmethod matchers.  If it is omitted, all registered xmethod matchers
+    from all loci are listed.  A locus could be 'global', a regular expression
+    matching the current program space's filename, or a regular expression
+    matching filenames of objfiles.  Locus could be 'progspace' to specify that
+    only xmethods from the current progspace should be listed.
+
+    NAME-REGEXP is a regular expression matching the names of xmethod
+    matchers.  If this omitted for a specified locus, then all registered
+    xmethods in the locus are listed.  To list only a certain xmethods
+    managed by a single matcher, the name regexp can be specified as
+    matcher-name-regexp;xmethod-name-regexp.
+    """
+
+    def __init__(self):
+        super(InfoXMethod, self).__init__("info xmethod",
+                                          gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        locus_re, matcher_re, name_re = parse_xm_command_args(arg)
+        print_xm_info(get_global_method_matchers(locus_re, matcher_re),
+                      name_re)
+        print_xm_info(
+            get_method_matchers_in_loci(
+                [gdb.current_progspace()], locus_re, matcher_re),
+            name_re)
+        print_xm_info(
+            get_method_matchers_in_loci(gdb.objfiles(), locus_re, matcher_re),
+            name_re)
+
+
+class EnableXMethod(gdb.Command):
+    """GDB command to enable a specified (group of) xmethod(s).
+
+    Usage: enable xmethod [locus-regexp [name-regexp]]
+
+    LOCUS-REGEXP is a regular expression matching the location of the
+    xmethod matchers.  If it is omitted, all registered xmethods matchers
+    from all loci are enabled.  A locus could be 'global', a regular expression
+    matching the current program space's filename, or a regular expression
+    matching filenames of objfiles.  Locus could be 'progspace' to specify that
+    only xmethods from the current progspace should be enabled.
+
+    NAME-REGEXP is a regular expression matching the names of xmethods
+    within a given locus.  If this omitted for a specified locus, then all
+    registered xmethod matchers in the locus are enabled.  To enable only
+    a certain xmethods managed by a single matcher, the name regexp can be
+    specified as matcher-name-regexp;xmethod-name-regexp.
+    """
+
+    def __init__(self):
+        super(EnableXMethod, self).__init__("enable xmethod",
+                                            gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        set_xm_status(arg, True)
+
+
+class DisableXMethod(gdb.Command):
+    """GDB command to disable a specified (group of) xmethod(s).
+
+    Usage: disable xmethod [locus-regexp [name-regexp]]
+
+    LOCUS-REGEXP is a regular expression matching the location of the
+    xmethod matchers.  If it is omitted, all registered xmethod matchers
+    from all loci are disabled.  A locus could be 'global', a regular
+    expression matching the current program space's filename, or a regular
+    expression filenames of objfiles. Locus could be 'progspace' to specify
+    that only xmethods from the current progspace should be disabled.
+
+    NAME-REGEXP is a regular expression matching the names of xmethods
+    within a given locus.  If this omitted for a specified locus, then all
+    registered xmethod matchers in the locus are disabled.  To disable
+    only a certain xmethods managed by a single matcher, the name regexp
+    can be specified as matcher-name-regexp;xmethod-name-regexp.
+    """
+
+    def __init__(self):
+        super(DisableXMethod, self).__init__("disable xmethod",
+                                             gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        set_xm_status(arg, False)
+
+
+def register_xmethod_commands():
+    """Installs the xmethod commands."""
+    InfoXMethod()
+    EnableXMethod()
+    DisableXMethod()
+
+
+register_xmethod_commands()

gdb/python/lib/gdb/xmethod.py

@@ -0,0 +1,259 @@
+# Python side of the support for xmethods.
+# Copyright (C) 2013-2014 Free Software Foundation, Inc.
+
+# 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/>.
+
+"""Utilities for defining xmethods"""
+
+import gdb
+import re
+import sys
+
+
+if sys.version_info[0] > 2:
+    # Python 3 removed basestring and long
+    basestring = str
+    long = int
+
+
+class XMethod(object):
+    """Base class (or a template) for an xmethod description.
+
+    Currently, the description requires only the 'name' and 'enabled'
+    attributes.  Description objects are managed by 'XMethodMatcher'
+    objects (see below).  Note that this is only a template for the
+    interface of the XMethodMatcher.methods objects.  One could use
+    this class or choose to use an object which supports this exact same
+    interface.  Also, an XMethodMatcher can choose not use it 'methods'
+    attribute.  In such cases this class (or an equivalent) is not used.
+
+    Attributes:
+        name: The name of the xmethod.
+        enabled: A boolean indicating if the xmethod is enabled.
+    """
+
+    def __init__(self, name):
+        self.name = name
+        self.enabled = True
+
+
+class XMethodMatcher(object):
+    """Abstract base class for matching an xmethod.
+
+    When looking for xmethods, GDB invokes the `match' method of a
+    registered xmethod matcher to match the object type and method name.
+    The `match' method in concrete classes derived from this class should
+    return an `XMethodWorker' object, or a list of `XMethodWorker'
+    objects if there is a match (see below for 'XMethodWorker' class).
+
+    Attributes:
+        name: The name of the matcher.
+        enabled: A boolean indicating if the matcher is enabled.
+        methods: A sequence of objects of type 'XMethod', or objects
+            which have at least the attributes of an 'XMethod' object.
+            This list is used by the 'enable'/'disable'/'info' commands to
+            enable/disable/list the xmethods registered with GDB.  See
+            the 'match' method below to know how this sequence is used.
+            This attribute is None if the matcher chooses not have any
+            xmethods managed by it.
+    """
+
+    def __init__(self, name):
+        """
+        Args:
+            name: An identifying name for the xmethod or the group of
+                  xmethods returned by the `match' method.
+        """
+        self.name = name
+        self.enabled = True
+        self.methods = None
+
+    def match(self, class_type, method_name):
+        """Match class type and method name.
+
+        In derived classes, it should return an XMethodWorker object, or a
+        sequence of 'XMethodWorker' objects.  Only those xmethod workers
+        whose corresponding 'XMethod' descriptor object is enabled should be
+        returned.
+
+        Args:
+            class_type: The class type (gdb.Type object) to match.
+            method_name: The name (string) of the method to match.
+        """
+        raise NotImplementedError("XMethodMatcher match")
+
+
+class XMethodWorker(object):
+    """Base class for all xmethod workers defined in Python.
+
+    An xmethod worker is an object which matches the method arguments, and
+    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.
+
+    Derived classes should override the 'get_arg_types' and '__call__' methods.
+    """
+
+    def get_arg_types(self):
+        """Return arguments types of an xmethod.
+
+        A sequence of gdb.Type objects corresponding to the arguments of the
+        xmethod are returned.  If the xmethod takes no arguments, then 'None'
+        or an empty sequence is returned.  If the xmethod takes only a single
+        argument, then a gdb.Type object or a sequence with a single gdb.Type
+        element is returned.
+        """
+        raise NotImplementedError("XMethodWorker get_arg_types")
+
+    def __call__(self, *args):
+        """Invoke 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.
+
+        Returns:
+            A gdb.Value corresponding to the value returned by the xmethod.
+            Returns 'None' if the method does not return anything.
+        """
+        raise NotImplementedError("XMethodWorker __call__")
+
+
+class SimpleXMethodMatcher(XMethodMatcher):
+    """A utility class to implement simple xmethod mathers and workers.
+
+    See the __init__ method below for information on how instances of this
+    class can be used.
+
+    For simple classes and methods, one can choose to use this class.  For
+    complex xmethods, which need to replace/implement template methods on
+    possibly template classes, one should implement their own xmethod
+    matchers and workers.  See py-xmethods.py in testsuite/gdb.python
+    directory of the GDB source tree for examples.
+    """
+
+    class SimpleXMethodWorker(XMethodWorker):
+        def __init__(self, method_function, arg_types):
+            self._arg_types = arg_types
+            self._method_function = method_function
+
+        def get_arg_types(self):
+            return self._arg_types
+
+        def __call__(self, *args):
+            return self._method_function(*args)
+
+
+    def __init__(self, name, class_matcher, method_matcher, method_function,
+                 *arg_types):
+        """
+        Args:
+            name: Name of the xmethod matcher.
+            class_matcher: A regular expression used to match the name of the
+                class whose method this xmethod is implementing/replacing.
+            method_matcher: A regular expression used to match the name of the
+                method this xmethod is implementing/replacing.
+            method_function: A Python callable which would be called via the
+                'invoke' method of the worker returned by the objects of this
+                class.  This callable should accept the object (*this) as the
+                first argument followed by the rest of the arguments to the
+                method. All arguments to this function should be gdb.Value
+                objects.
+            arg_types: The gdb.Type objects corresponding to the arguments that
+                this xmethod takes. It can be None, or an empty sequence,
+                or a single gdb.Type object, or a sequence of gdb.Type objects.
+        """
+        XMethodMatcher.__init__(self, name)
+        assert callable(method_function), (
+            "The 'method_function' argument to 'SimpleXMethodMatcher' "
+            "__init__ method should be a callable.")
+        self._method_function = method_function
+        self._class_matcher = class_matcher
+        self._method_matcher = method_matcher
+        self._arg_types = arg_types
+
+    def match(self, class_type, method_name):
+        cm = re.match(self._class_matcher, str(class_type.unqualified().tag))
+        mm = re.match(self._method_matcher, method_name)
+        if cm and mm:
+            return SimpleXMethodMatcher.SimpleXMethodWorker(
+                self._method_function, self._arg_types)
+
+
+# A helper function for register_xmethod_matcher which returns an error
+# object if MATCHER is not having the requisite attributes in the proper
+# format.
+
+def _validate_xmethod_matcher(matcher):
+    if not hasattr(matcher, "match"):
+        return TypeError("Xmethod matcher is missing method: match")
+    if not hasattr(matcher, "name"):
+        return TypeError("Xmethod matcher is missing attribute: name")
+    if not hasattr(matcher, "enabled"):
+        return TypeError("Xmethod matcher is missing attribute: enabled")
+    if not isinstance(matcher.name, basestring):
+        return TypeError("Attribute 'name' of xmethod matcher is not a "
+                         "string")
+    if matcher.name.find(";") >= 0:
+        return ValueError("Xmethod matcher name cannot contain ';' in it")
+
+
+# A helper function for register_xmethod_matcher which looks up an 
+# xmethod matcher with NAME in LOCUS.  Returns the index of the xmethod
+# matcher in 'xmethods' sequence attribute of the LOCUS.  If NAME is not
+# found in LOCUS, then -1 is returned.
+
+def _lookup_xmethod_matcher(locus, name):
+    for i in range(0, len(locus.xmethods)):
+        if locus.xmethods[i].name == name:
+            return i
+    return -1
+
+
+def register_xmethod_matcher(locus, matcher, replace=False):
+    """Registers a xmethod matcher MATCHER with a LOCUS.
+
+    Arguments:
+        locus: The locus in which the xmethods should be registered.
+            It can be 'None' to indicate that the xmethods should be
+            registered globally. Or, it could be a gdb.Objfile or a
+            gdb.Progspace object in which the xmethods should be
+            registered.
+        matcher: The xmethod matcher to register with the LOCUS.  It
+            should be an instance of 'XMethodMatcher' class.
+        replace: If True, replace any existing xmethod matcher with the
+            same name in the locus.  Otherwise, if a matcher with the same name
+            exists in the locus, raise an exception.
+    """
+    err = _validate_xmethod_matcher(matcher)
+    if err:
+        raise err
+    if not locus:
+        locus = gdb
+    if locus == gdb:
+        locus_name = "global"
+    else:
+        locus_name = locus.filename
+    index = _lookup_xmethod_matcher(locus, matcher.name)
+    if index >= 0:
+        if replace:
+            del locus.xmethods[index]
+        else:
+            raise RuntimeError("Xmethod matcher already registered with "
+                               "%s: %s" % (locus_name, matcher.name))
+    if gdb.parameter("verbose"):
+        gdb.write("Registering xmethod matcher '%s' with %s' ...\n")
+    locus.xmethods.insert(0, matcher)

gdb/python/py-objfile.c

@@ -37,6 +37,9 @@ typedef struct
   PyObject *frame_filters;
   /* The type-printer list.  */
   PyObject *type_printers;
+
+  /* The debug method matcher list.  */
+  PyObject *xmethods;
 } objfile_object;
 
 static PyTypeObject objfile_object_type
@@ -67,6 +70,7 @@ objfpy_dealloc (PyObject *o)
   Py_XDECREF (self->printers);
   Py_XDECREF (self->frame_filters);
   Py_XDECREF (self->type_printers);
+  Py_XDECREF (self->xmethods);
   Py_TYPE (self)->tp_free (self);
 }
 
@@ -99,6 +103,13 @@ objfpy_new (PyTypeObject *type, PyObject *args, PyObject *keywords)
 	  Py_DECREF (self);
 	  return NULL;
 	}
+
+      self->xmethods = PyList_New (0);
+      if (self->xmethods == NULL)
+	{
+	  Py_DECREF (self);
+	  return NULL;
+	}
     }
   return (PyObject *) self;
 }
@@ -193,6 +204,17 @@ objfpy_get_type_printers (PyObject *o, void *ignore)
   return self->type_printers;
 }
 
+/* Get the 'xmethods' attribute.  */
+
+PyObject *
+objfpy_get_xmethods (PyObject *o, void *ignore)
+{
+  objfile_object *self = (objfile_object *) o;
+
+  Py_INCREF (self->xmethods);
+  return self->xmethods;
+}
+
 /* Set the 'type_printers' attribute.  */
 
 static int
@@ -292,6 +314,13 @@ objfile_to_objfile_object (struct objfile *objfile)
 	      return NULL;
 	    }
 
+	  object->xmethods = PyList_New (0);
+	  if (object->xmethods == NULL)
+	    {
+	      Py_DECREF (object);
+	      return NULL;
+	    }
+
 	  set_objfile_data (objfile, objfpy_objfile_data_key, object);
 	}
     }
@@ -333,6 +362,8 @@ static PyGetSetDef objfile_getset[] =
     objfpy_set_frame_filters, "Frame Filters.", NULL },
   { "type_printers", objfpy_get_type_printers, objfpy_set_type_printers,
     "Type printers.", NULL },
+  { "xmethods", objfpy_get_xmethods, NULL,
+    "Debug methods.", NULL },
   { NULL }
 };
 

gdb/python/py-progspace.c

@@ -39,6 +39,9 @@ typedef struct
   PyObject *frame_filters;
   /* The type-printer list.  */
   PyObject *type_printers;
+
+  /* The debug method list.  */
+  PyObject *xmethods;
 } pspace_object;
 
 static PyTypeObject pspace_object_type
@@ -75,6 +78,7 @@ pspy_dealloc (PyObject *self)
   Py_XDECREF (ps_self->printers);
   Py_XDECREF (ps_self->frame_filters);
   Py_XDECREF (ps_self->type_printers);
+  Py_XDECREF (ps_self->xmethods);
   Py_TYPE (self)->tp_free (self);
 }
 
@@ -107,6 +111,13 @@ pspy_new (PyTypeObject *type, PyObject *args, PyObject *keywords)
 	  Py_DECREF (self);
 	  return NULL;
 	}
+
+      self->xmethods = PyList_New (0);
+      if (self->xmethods == NULL)
+	{
+	  Py_DECREF (self);
+	  return NULL;
+	}
     }
   return (PyObject *) self;
 }
@@ -201,6 +212,17 @@ pspy_get_type_printers (PyObject *o, void *ignore)
   return self->type_printers;
 }
 
+/* Get the 'xmethods' attribute.  */
+
+PyObject *
+pspy_get_xmethods (PyObject *o, void *ignore)
+{
+  pspace_object *self = (pspace_object *) o;
+
+  Py_INCREF (self->xmethods);
+  return self->xmethods;
+}
+
 /* Set the 'type_printers' attribute.  */
 
 static int
@@ -297,6 +319,13 @@ pspace_to_pspace_object (struct program_space *pspace)
 	      return NULL;
 	    }
 
+	  object->xmethods = PyList_New (0);
+	  if (object->xmethods == NULL)
+	    {
+	      Py_DECREF (object);
+	      return NULL;
+	    }
+
 	  set_program_space_data (pspace, pspy_pspace_data_key, object);
 	}
     }
@@ -329,6 +358,8 @@ static PyGetSetDef pspace_getset[] =
     "Frame filters.", NULL },
   { "type_printers", pspy_get_type_printers, pspy_set_type_printers,
     "Type printers.", NULL },
+  { "xmethods", pspy_get_xmethods, NULL,
+    "Debug methods.", NULL },
   { NULL }
 };
 

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;
+}

gdb/python/python-internal.h

@@ -307,6 +307,24 @@ extern enum ext_lang_bp_stop gdbpy_breakpoint_cond_says_stop
   (const struct extension_language_defn *, struct breakpoint *);
 extern int gdbpy_breakpoint_has_cond (const struct extension_language_defn *,
 				      struct breakpoint *b);
+
+extern void *gdbpy_clone_xmethod_worker_data
+  (const struct extension_language_defn *extlang, void *data);
+extern void gdbpy_free_xmethod_worker_data
+  (const struct extension_language_defn *extlang, void *data);
+extern 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);
+extern 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);
+extern struct value *gdbpy_invoke_xmethod
+  (const struct extension_language_defn *extlang,
+   struct xmethod_worker *worker,
+   struct value *obj, struct value **args, int nargs);
 
 PyObject *gdbpy_history (PyObject *self, PyObject *args);
 PyObject *gdbpy_breakpoints (PyObject *, PyObject *);
@@ -345,11 +363,13 @@ PyObject *pspace_to_pspace_object (struct program_space *)
     CPYCHECKER_RETURNS_BORROWED_REF;
 PyObject *pspy_get_printers (PyObject *, void *);
 PyObject *pspy_get_frame_filters (PyObject *, void *);
+PyObject *pspy_get_xmethods (PyObject *, void *);
 
 PyObject *objfile_to_objfile_object (struct objfile *)
     CPYCHECKER_RETURNS_BORROWED_REF;
 PyObject *objfpy_get_printers (PyObject *, void *);
 PyObject *objfpy_get_frame_filters (PyObject *, void *);
+PyObject *objfpy_get_xmethods (PyObject *, void *);
 
 PyObject *gdbarch_to_arch_object (struct gdbarch *gdbarch);
 
@@ -430,6 +450,8 @@ int gdbpy_initialize_new_objfile_event (void)
   CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
 int gdbpy_initialize_arch (void)
   CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
+int gdbpy_initialize_xmethods (void)
+  CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
 
 struct cleanup *make_cleanup_py_decref (PyObject *py);
 struct cleanup *make_cleanup_py_xdecref (PyObject *py);

gdb/python/python.c

@@ -186,7 +186,13 @@ static const struct extension_language_ops python_extension_ops =
   gdbpy_set_quit_flag,
   gdbpy_check_quit_flag,
 
-  gdbpy_before_prompt_hook
+  gdbpy_before_prompt_hook,
+
+  gdbpy_clone_xmethod_worker_data,
+  gdbpy_free_xmethod_worker_data,
+  gdbpy_get_matching_xmethod_workers,
+  gdbpy_get_xmethod_arg_types,
+  gdbpy_invoke_xmethod
 };
 
 /* Architecture and language to be used in callbacks from
@@ -1752,7 +1758,8 @@ message == an error message without a stack will be printed."),
       || gdbpy_initialize_exited_event () < 0
       || gdbpy_initialize_thread_event () < 0
       || gdbpy_initialize_new_objfile_event ()  < 0
-      || gdbpy_initialize_arch () < 0)
+      || gdbpy_initialize_arch () < 0
+      || gdbpy_initialize_xmethods () < 0)
     goto fail;
 
   gdbpy_to_string_cst = PyString_FromString ("to_string");

gdb/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2014-06-03  Siva Chandra Reddy  <sivachandra@google.com>
+
+	* 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.
+
 2014-06-03  Joel Brobecker  <brobecker@adacore.com>
 	    Pedro Alves  <palves@redhat.com>
 

gdb/testsuite/gdb.python/py-xmethods.cc

@@ -0,0 +1,170 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   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 <iostream>
+
+using namespace std;
+
+namespace dop
+{
+
+class A
+{
+public:
+  int a;
+  int array [10];
+  virtual ~A ();
+  int operator+ (const A &obj);
+  int operator- (const A &obj);
+  virtual int geta (void);
+};
+
+A::~A () { }
+
+int
+A::operator+ (const A &obj)
+{
+  cout << "From CC <A_plus_A>:" << endl;
+  return a + obj.a;
+}
+
+int
+A::operator- (const A &obj)
+{
+  cout << "From CC <A_minus_A>:" << endl;
+  return a - obj.a;
+}
+
+int
+A::geta (void)
+{
+  cout << "From CC A::geta:" << endl;
+  return a;
+}
+
+class B : public A
+{
+public:
+  virtual int geta (void);
+};
+
+int
+B::geta (void)
+{
+  cout << "From CC B::geta:" << endl;
+  return 2 * a;
+}
+
+typedef B Bt;
+
+typedef Bt Btt;
+
+class E : public A
+{
+public:
+  /* This class has a member named 'a', while the base class also has a
+     member named 'a'.  When one invokes A::geta(), A::a should be
+     returned and not E::a as the 'geta' method is defined on class 'A'.
+     This class tests this aspect of debug methods.  */
+  int a;
+};
+
+template <typename T>
+class G
+{
+ public:
+  template <typename T1>
+  int size_diff ();
+
+  template <int M>
+  int size_mul ();
+
+  template <typename T1>
+  T mul(const T1 t1);
+
+ public:
+  T t;
+};
+
+template <typename T>
+template <typename T1>
+int
+G<T>::size_diff ()
+{
+  cout << "From CC G<>::size_diff:" << endl;
+  return sizeof (T1) - sizeof (T);
+}
+
+template <typename T>
+template <int M>
+int
+G<T>::size_mul ()
+{
+  cout << "From CC G<>::size_mul:" << endl;
+  return M * sizeof (T);
+}
+
+template <typename T>
+template <typename T1>
+T
+G<T>::mul (const T1 t1)
+{
+  cout << "From CC G<>::mul:" << endl;
+  return t1 * t;
+}
+
+}  // namespaxe dop
+
+using namespace dop;
+
+int main(void)
+{
+  A a1, a2;
+  a1.a = 5;
+  a2.a = 10;
+
+  B b1;
+  b1.a = 30;
+  A *a_ptr = &b1;
+
+  Bt bt;
+  bt.a = 40;
+
+  Btt btt;
+  btt.a = -5;
+
+  G<int> g, *g_ptr;
+  g.t = 5;
+  g_ptr = &g;
+
+  E e;
+  E &e_ref = e;
+  E *e_ptr = &e;
+  e.a = 1000;
+  e.A::a = 100;
+
+  int diff = g.size_diff<float> ();
+  int smul = g.size_mul<2> ();
+  int mul = g.mul (1.0);
+
+  for (int i = 0; i < 10; i++)
+    {
+      a1.array[i] = a2.array[i] = i;
+    }
+
+  return 0; /* Break here.  */
+}

gdb/testsuite/gdb.python/py-xmethods.exp

@@ -0,0 +1,127 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# 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/>.
+
+# This file is part of the GDB testsuite.  It tests the debug methods
+# feature in the Python extension language.
+
+load_lib gdb-python.exp
+
+if { [skip_cplus_tests] } { continue }
+
+standard_testfile py-xmethods.cc
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+if ![runto_main] {
+   return -1
+}
+
+set xmethods_script [gdb_remote_download host \
+		     ${srcdir}/${subdir}/${testfile}.py]
+
+gdb_breakpoint [gdb_get_line_number "Break here."]
+gdb_continue_to_breakpoint "Break here" ".*Break here.*"
+
+# Tests before loading the debug methods.
+gdb_test "p a1 + a2" "From CC <A_plus_A>.*15" "Before: a1 + a2"
+gdb_test "p a2 - a1" "From CC <A_minus_A>.*5" "Before: a1 - a2"
+gdb_test "p b1 - a1" "From CC <A_minus_A>.*25" "Before: b1 - a1"
+gdb_test "p a1.geta()" "From CC A::geta.*5" "Before: a1.geta()"
+gdb_test "p ++a1" "No symbol.*" "Before: ++a1"
+gdb_test "p a1.getarrayind(5)" "Couldn't find method.*" \
+  "Before: a1.getarrayind(5)"
+gdb_test "p a_ptr->geta()" "From CC B::geta.*60" "Before: a_ptr->geta()"
+gdb_test "p e.geta()" "From CC A::geta.*100" "Before: e.geta()"
+gdb_test "p g.size_diff<float>()" "From CC G<>::size_diff.*" \
+  "Before: g.size_diff<float>()"
+gdb_test "p g.size_diff<unsigned long>()" "Couldn't find method.*" \
+  "Before: g.size_diff<unsigned long>()"
+gdb_test "p g.size_mul<2>()" "From CC G<>::size_mul.*" \
+  "Before: g.size_mul<2>()"
+gdb_test "p g.size_mul<5>()" "Couldn't find method.*" \
+  "Before: g.size_mul<5>()"
+gdb_test "p g.mul<double>(2.0)" "From CC G<>::mul.*" \
+  "Before: g.mul<double>(2.0)"
+gdb_test "p g.mul<char>('a')" "Couldn't find method.*" \
+  "Before: g.mul<char>('a')"
+
+# Load the script which adds the debug methods.
+gdb_test_no_output "source ${xmethods_script}" "load the script file"
+
+# Tests after loading debug methods.
+gdb_test "p a1 + a2" "From Python <A_plus_A>.*15" "After: a1 + a2"
+gdb_test "p a2 - a1" "From CC <A_minus_A>.*5" "After: a1 - a2"
+gdb_test "p b1 + a1" "From Python <A_plus_A>.*35" "After: b1 + a1"
+gdb_test "p b1 - a1" "From CC <A_minus_A>.*25" "After: b1 - a1"
+gdb_test "p a1.geta()" "From Python <A_geta>.*5" "After: a1.geta()"
+gdb_test "p ++a1" "From Python <plus_plus_A>.*6" "After: ++a1"
+gdb_test "p a1.getarrayind(5)" "From Python <A_getarrayind>.*5" \
+  "After: a1.getarrayind(5)"
+# Note the following test.  Xmethods on dynamc types are not looked up
+# currently.  Hence, even though a_ptr points to a B object, the xmethod
+# defined for A objects is invoked.
+gdb_test "p a_ptr->geta()" "From Python <A_geta>.*30" "After: a_ptr->geta()"
+gdb_test "p e.geta()" "From Python <A_geta>.*100" "After: e.geta()"
+gdb_test "p e_ptr->geta()" "From Python <A_geta>.*100" "After: e_ptr->geta()"
+gdb_test "p e_ref.geta()" "From Python <A_geta>.*100" "After: e_ref.geta()"
+gdb_test "p e.method(10)" "From Python <E_method_int>.*" "After: e.method(10)"
+gdb_test "p e.method('a')" "From Python <E_method_char>.*" \
+  "After: e.method('a')"
+gdb_test "p g.size_diff<float>  ()" "From Python G<>::size_diff.*" \
+  "After: g.size_diff<float>()"
+gdb_test "p g.size_diff<  unsigned long  >()" "From Python G<>::size_diff.*" \
+  "After: g.size_diff<unsigned long>()"
+gdb_test "p g.size_mul<2>()" "From Python G<>::size_mul.*" \
+  "After: g.size_mul<2>()"
+gdb_test "p g.size_mul<  5  >()" "From Python G<>::size_mul.*" \
+  "After: g.size_mul<  5  >()"
+gdb_test "p g.mul<double>(2.0)" "From Python G<>::mul.*" \
+  "After: g.mul<double>(2.0)"
+gdb_test "p g.mul<char>('a')" "From Python G<>::mul.*" \
+gdb_test "p g_ptr->mul<char>('a')" "From Python G<>::mul.*" \
+  "After: g_ptr->mul<char>('a')"
+
+# Tests for 'disable/enable xmethod' command.
+gdb_test_no_output "disable xmethod .*xmethods G_methods" \
+  "Disable G_methods"
+gdb_test "p g.mul<char>('a')" "Couldn't find method.*" \
+  "g.mul<char>('a') after disabling G_methods"
+gdb_test_no_output "enable xmethod .*xmethods G_methods" \
+  "Enable G_methods"
+gdb_test "p g.mul<char>('a')" "From Python G<>::mul.*" \
+  "After enabling G_methods"
+gdb_test_no_output "disable xmethod .*xmethods G_methods;mul" \
+  "Disable G_methods;mul"
+gdb_test "p g.mul<char>('a')" "Couldn't find method.*" \
+  "g.mul<char>('a') after disabling G_methods;mul"
+gdb_test_no_output "enable xmethod .*xmethods G_methods;mul" \
+  "Enable G_methods;mul"
+gdb_test "p g.mul<char>('a')" "From Python G<>::mul.*" \
+  "After enabling G_methods;mul"
+
+# Test for 'info xmethods' command
+gdb_test "info xmethod global plus" "global.*plus_plus_A" \
+  "info xmethod global plus 1"
+gdb_test_no_output "disable xmethod .*xmethods E_methods;method_int" \
+  "disable xmethod .*xmethods E_methods;method_int"
+gdb_test "info xmethod .*xmethods E_methods;method_int" ".* \\\[disabled\\\]" \
+  "info xmethod xmethods E_methods;method_int"
+
+remote_file host delete ${xmethods_script}

gdb/testsuite/gdb.python/py-xmethods.py

@@ -0,0 +1,218 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# 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/>.
+
+# This file is part of the GDB testsuite.  It test the xmethods support
+# in the Python extension language.
+
+import gdb
+import re
+
+from gdb.xmethod import XMethod
+from gdb.xmethod import XMethodMatcher, XMethodWorker
+from gdb.xmethod import SimpleXMethodMatcher
+
+
+def A_plus_A(obj, opr):
+  print ('From Python <A_plus_A>:')
+  return obj['a'] + opr['a']
+
+
+def plus_plus_A(obj):
+  print ('From Python <plus_plus_A>:')
+  return obj['a'] + 1
+
+
+def A_geta(obj):
+  print ('From Python <A_geta>:')
+  return obj['a']
+
+
+def A_getarrayind(obj, index):
+  print 'From Python <A_getarrayind>:'
+  return obj['array'][index]
+
+
+type_A = gdb.parse_and_eval('(dop::A *) 0').type.target()
+type_B = gdb.parse_and_eval('(dop::B *) 0').type.target()
+type_int = gdb.parse_and_eval('(int *) 0').type.target()
+
+
+# The E class matcher and worker test two things:
+#   1. xmethod returning None.
+#   2. Matcher returning a list of workers.
+
+class E_method_char_worker(XMethodWorker):
+    def __init__(self):
+        pass
+
+    def get_arg_types(self):
+        return gdb.lookup_type('char')
+
+    def __call__(self, obj, arg):
+        print 'From Python <E_method_char>'
+        return None
+
+
+class E_method_int_worker(XMethodWorker):
+    def __init__(self):
+        pass
+
+    def get_arg_types(self):
+        return gdb.lookup_type('int')
+
+    def __call__(self, obj, arg):
+        print 'From Python <E_method_int>'
+        return None
+
+
+class E_method_matcher(XMethodMatcher):
+    def __init__(self):
+        XMethodMatcher.__init__(self, 'E_methods')
+        self.methods = [XMethod('method_int'), XMethod('method_char')]
+
+    def match(self, class_type, method_name):
+        class_tag = class_type.unqualified().tag
+        if not re.match('^dop::E$', class_tag):
+            return None
+	if not re.match('^method$', method_name):
+            return None
+        workers = []
+        if self.methods[0].enabled:
+            workers.append(E_method_int_worker())
+        if self.methods[1].enabled:
+            workers.append(E_method_char_worker())
+        return workers
+
+
+# The G class method matcher and worker illustrate how to write
+# xmethod matchers and workers for template classes and template
+# methods.
+
+class G_size_diff_worker(XMethodWorker):
+    def __init__(self, class_template_type, method_template_type):
+        self._class_template_type = class_template_type
+        self._method_template_type = method_template_type
+
+    def get_arg_types(self):
+        pass
+
+    def __call__(self, obj):
+        print ('From Python G<>::size_diff()')
+        return (self._method_template_type.sizeof -
+                self._class_template_type.sizeof)
+
+
+class G_size_mul_worker(XMethodWorker):
+    def __init__(self, class_template_type, method_template_val):
+        self._class_template_type = class_template_type
+        self._method_template_val = method_template_val
+
+    def get_arg_types(self):
+        pass
+
+    def __call__(self, obj):
+        print ('From Python G<>::size_mul()')
+        return self._class_template_type.sizeof * self._method_template_val
+
+
+class G_mul_worker(XMethodWorker):
+    def __init__(self, class_template_type, method_template_type):
+        self._class_template_type = class_template_type
+        self._method_template_type = method_template_type
+
+    def get_arg_types(self):
+        return self._method_template_type
+
+    def __call__(self, obj, arg):
+        print ('From Python G<>::mul()')
+        return obj['t'] * arg
+
+
+class G_methods_matcher(XMethodMatcher):
+    def __init__(self):
+        XMethodMatcher.__init__(self, 'G_methods')
+        self.methods = [XMethod('size_diff'),
+                        XMethod('size_mul'),
+                        XMethod('mul')]
+
+    def _is_enabled(self, name):
+        for method in self.methods:
+            if method.name == name and method.enabled:
+                return True
+
+    def match(self, class_type, method_name):
+        class_tag = class_type.unqualified().tag
+        if not re.match('^dop::G<[ ]*[_a-zA-Z][ _a-zA-Z0-9]*>$',
+                        class_tag):
+            return None
+        t_name = class_tag[7:-1]
+        try:
+            t_type = gdb.lookup_type(t_name)
+        except gdb.error:
+            return None
+        if re.match('^size_diff<[ ]*[_a-zA-Z][ _a-zA-Z0-9]*>$', method_name):
+            if not self._is_enabled('size_diff'):
+                return None
+            t1_name = method_name[10:-1]
+            try:
+                t1_type = gdb.lookup_type(t1_name)
+                return G_size_diff_worker(t_type, t1_type)
+            except gdb.error:
+                return None
+        if re.match('^size_mul<[ ]*[0-9]+[ ]*>$', method_name):
+            if not self._is_enabled('size_mul'):
+                return None
+            m_val = int(method_name[9:-1])
+            return G_size_mul_worker(t_type, m_val)
+        if re.match('^mul<[ ]*[_a-zA-Z][ _a-zA-Z0-9]*>$', method_name):
+            if not self._is_enabled('mul'):
+                return None
+            t1_name = method_name[4:-1]
+            try:
+                t1_type = gdb.lookup_type(t1_name)
+                return G_mul_worker(t_type, t1_type)
+            except gdb.error:
+                return None
+
+
+global_dm_list = [
+    SimpleXMethodMatcher('A_plus_A',
+                         '^dop::A$',
+                         'operator\+',
+                         A_plus_A,
+                         # This is a replacement, hence match the arg type
+                         # exactly!
+                         type_A.const().reference()),
+    SimpleXMethodMatcher('plus_plus_A',
+                         '^dop::A$',
+                         'operator\+\+',
+                         plus_plus_A),
+    SimpleXMethodMatcher('A_geta',
+                         '^dop::A$',
+                         '^geta$',
+                         A_geta),
+    SimpleXMethodMatcher('A_getarrayind',
+                         '^dop::A$',
+                         '^getarrayind$',
+                         A_getarrayind,
+                         type_int),
+]
+
+for matcher in global_dm_list:
+    gdb.xmethod.register_xmethod_matcher(gdb, matcher)
+gdb.xmethod.register_xmethod_matcher(gdb.current_progspace(),
+                                     G_methods_matcher())
+gdb.xmethod.register_xmethod_matcher(gdb.current_progspace(),
+                                     E_method_matcher())