gdb/python: New method to access list of register groups

Add a new method gdb.Architecture.register_groups which returns a new
object of type gdb.RegisterGroupsIterator.  This new iterator then
returns objects of type gdb.RegisterGroup.

Each gdb.RegisterGroup object just wraps a single reggroup pointer,
and (currently) has just one read-only property 'name' that is a
string, the name of the register group.

As with the previous commit (adding gdb.RegisterDescriptor) I made
gdb.RegisterGroup an object rather than just a string in case we want
to add additional properties in the future.

gdb/ChangeLog:

	* NEWS: Mention additions to Python API.
	* python/py-arch.c (archpy_register_groups): New function.
	(arch_object_methods): Add 'register_groups' method.
	* python/py-registers.c (reggroup_iterator_object): New struct.
	(reggroup_object): New struct.
	(gdbpy_new_reggroup): New function.
	(gdbpy_reggroup_to_string): New function.
	(gdbpy_reggroup_name): New function.
	(gdbpy_reggroup_iter): New function.
	(gdbpy_reggroup_iter_next): New function.
	(gdbpy_new_reggroup_iterator): New function
	(gdbpy_initialize_registers): Register new types.
	(reggroup_iterator_object_type): Define new Python type.
	(gdbpy_reggroup_getset): New static global.
	(reggroup_object_type): Define new Python type.
	* python/python-internal.h

gdb/testsuite/ChangeLog:

	* gdb.python/py-arch-reg-groups.exp: New file.

gdb/doc/ChangeLog:

	* gdb.texi (Registers): Add @anchor for 'info registers
	<reggroup>' command.
	* python.texi (Architectures In Python): Document new
	register_groups method.
	(Registers In Python): Document two new object types related to
	register groups.

3 files changed, 214 insertions, 0 deletions

diff --git a/gdb/python/py-arch.c b/gdb/python/py-arch.c
index 15f9f50..d9eaf81 100644
--- a/gdb/python/py-arch.c
+++ b/gdb/python/py-arch.c
@@ -248,6 +248,20 @@ archpy_registers (PyObject *self, PyObject *args, PyObject *kw)
   return gdbpy_new_register_descriptor_iterator (gdbarch, group_name);
 }
 
+/* Implementation of gdb.Architecture.register_groups (self) -> Iterator.
+   Returns an iterator that will give up all valid register groups in the
+   architecture SELF.  */
+
+static PyObject *
+archpy_register_groups (PyObject *self, PyObject *args)
+{
+  struct gdbarch *gdbarch = NULL;
+
+  /* Extract the gdbarch from the self object.  */
+  ARCHPY_REQUIRE_VALID (self, gdbarch);
+  return gdbpy_new_reggroup_iterator (gdbarch);
+}
+
 /* Initializes the Architecture class in the gdb module.  */
 
 int
@@ -276,6 +290,10 @@ END_PC." },
     "registers ([ group-name ]) -> Iterator.\n\
 Return an iterator of register descriptors for the registers in register\n\
 group GROUP-NAME." },
+  { "register_groups", archpy_register_groups,
+    METH_NOARGS,
+    "register_groups () -> Iterator.\n\
+Return an iterator over all of the register groups in this architecture." },
   {NULL}  /* Sentinel */
 };
 
diff --git a/gdb/python/py-registers.c b/gdb/python/py-registers.c
index 6ccd17e..db0fe37 100644
--- a/gdb/python/py-registers.c
+++ b/gdb/python/py-registers.c
@@ -56,6 +56,67 @@ typedef struct {
 extern PyTypeObject register_descriptor_object_type
     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("register_descriptor_object");
 
+/* Structure for iterator over register groups.  */
+typedef struct {
+  PyObject_HEAD
+
+  /* The last register group returned.  Initially this will be NULL.  */
+  struct reggroup *reggroup;
+
+  /* Pointer back to the architecture we're finding registers for.  */
+  struct gdbarch *gdbarch;
+} reggroup_iterator_object;
+
+extern PyTypeObject reggroup_iterator_object_type
+    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("reggroup_iterator_object");
+
+/* A register group object.  */
+typedef struct {
+  PyObject_HEAD
+
+  /* The register group being described.  */
+  struct reggroup *reggroup;
+} reggroup_object;
+
+extern PyTypeObject reggroup_object_type
+    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("reggroup_object");
+
+/* Create a new gdb.RegisterGroup object wrapping REGGROUP.  */
+
+static PyObject *
+gdbpy_new_reggroup (struct reggroup *reggroup)
+{
+  /* Create a new object and fill in its details.  */
+  reggroup_object *group
+    = PyObject_New (reggroup_object, &reggroup_object_type);
+  if (group == NULL)
+    return NULL;
+  group->reggroup = reggroup;
+  return (PyObject *) group;
+}
+
+/* Convert a gdb.RegisterGroup to a string, it just returns the name of
+   the register group.  */
+
+static PyObject *
+gdbpy_reggroup_to_string (PyObject *self)
+{
+  reggroup_object *group = (reggroup_object *) self;
+  struct reggroup *reggroup = group->reggroup;
+
+  const char *name = reggroup_name (reggroup);
+  return PyString_FromString (name);
+}
+
+/* Implement gdb.RegisterGroup.name (self) -> String.
+   Return a string that is the name of this register group.  */
+
+static PyObject *
+gdbpy_reggroup_name (PyObject *self, void *closure)
+{
+  return gdbpy_reggroup_to_string (self);
+}
+
 /* Create an return a new gdb.RegisterDescriptor object.  */
 static PyObject *
 gdbpy_new_register_descriptor (struct gdbarch *gdbarch,
@@ -96,6 +157,54 @@ gdbpy_register_descriptor_name (PyObject *self, void *closure)
   return gdbpy_register_descriptor_to_string (self);
 }
 
+/* Return a reference to the gdb.RegisterGroupsIterator object.  */
+
+static PyObject *
+gdbpy_reggroup_iter (PyObject *self)
+{
+  Py_INCREF (self);
+  return self;
+}
+
+/* Return the next gdb.RegisterGroup object from the iterator.  */
+
+static PyObject *
+gdbpy_reggroup_iter_next (PyObject *self)
+{
+  reggroup_iterator_object *iter_obj
+    = (reggroup_iterator_object *) self;
+  struct gdbarch *gdbarch = iter_obj->gdbarch;
+
+  struct reggroup *next_group = reggroup_next (gdbarch, iter_obj->reggroup);
+  if (next_group == NULL)
+    {
+      PyErr_SetString (PyExc_StopIteration, _("No more groups"));
+      return NULL;
+    }
+
+  iter_obj->reggroup = next_group;
+  return gdbpy_new_reggroup (iter_obj->reggroup);
+}
+
+/* Return a new gdb.RegisterGroupsIterator over all the register groups in
+   GDBARCH.  */
+
+PyObject *
+gdbpy_new_reggroup_iterator (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != nullptr);
+
+  /* Create a new object and fill in its internal state.  */
+  reggroup_iterator_object *iter
+    = PyObject_New (reggroup_iterator_object,
+		    &reggroup_iterator_object_type);
+  if (iter == NULL)
+    return NULL;
+  iter->reggroup = NULL;
+  iter->gdbarch = gdbarch;
+  return (PyObject *) iter;
+}
+
 /* Create and return a new gdb.RegisterDescriptorIterator object which
    will iterate over all registers in GROUP_NAME for GDBARCH.  If
    GROUP_NAME is either NULL or the empty string then the ALL_REGGROUP is
@@ -190,6 +299,22 @@ gdbpy_initialize_registers ()
        (PyObject *) &register_descriptor_object_type) < 0)
     return -1;
 
+  reggroup_iterator_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&reggroup_iterator_object_type) < 0)
+    return -1;
+  if (gdb_pymodule_addobject
+      (gdb_module, "RegisterGroupsIterator",
+       (PyObject *) &reggroup_iterator_object_type) < 0)
+    return -1;
+
+  reggroup_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&reggroup_object_type) < 0)
+    return -1;
+  if (gdb_pymodule_addobject
+      (gdb_module, "RegisterGroup",
+       (PyObject *) &reggroup_object_type) < 0)
+    return -1;
+
   register_descriptor_iterator_object_type.tp_new = PyType_GenericNew;
   if (PyType_Ready (&register_descriptor_iterator_object_type) < 0)
     return -1;
@@ -267,3 +392,73 @@ PyTypeObject register_descriptor_object_type = {
   0,				  /*tp_members */
   gdbpy_register_descriptor_getset			/*tp_getset */
 };
+
+PyTypeObject reggroup_iterator_object_type = {
+  PyVarObject_HEAD_INIT (NULL, 0)
+  "gdb.RegisterGroupsIterator",	  /*tp_name*/
+  sizeof (reggroup_iterator_object),		/*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  0,				  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  0,				  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,	/*tp_flags*/
+  "GDB register groups iterator object",	/*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  gdbpy_reggroup_iter,		  /*tp_iter */
+  gdbpy_reggroup_iter_next,	  /*tp_iternext */
+  0				  /*tp_methods */
+};
+
+static gdb_PyGetSetDef gdbpy_reggroup_getset[] = {
+  { "name", gdbpy_reggroup_name, NULL,
+    "The name of this register group.", NULL },
+  { NULL }  /* Sentinel */
+};
+
+PyTypeObject reggroup_object_type = {
+  PyVarObject_HEAD_INIT (NULL, 0)
+  "gdb.RegisterGroup",		  /*tp_name*/
+  sizeof (reggroup_object),	  /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  0,				  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  gdbpy_reggroup_to_string,	  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT,		  /*tp_flags*/
+  "GDB register group object",	  /*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  0,				  /*tp_iter */
+  0,				  /*tp_iternext */
+  0,				  /*tp_methods */
+  0,				  /*tp_members */
+  gdbpy_reggroup_getset		  /*tp_getset */
+};
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 758dc55..1e6dcf3 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -475,6 +475,7 @@ PyObject *gdbarch_to_arch_object (struct gdbarch *gdbarch);
 
 PyObject *gdbpy_new_register_descriptor_iterator (struct gdbarch *gdbarch,
 						  const char *group_name);
+PyObject *gdbpy_new_reggroup_iterator (struct gdbarch *gdbarch);
 
 gdbpy_ref<thread_object> create_thread_object (struct thread_info *tp);
 gdbpy_ref<> thread_to_thread_object (thread_info *thr);;