Use registry in gdbarch

gdbarch implements its own registry-like approach.  This patch changes
it to instead use registry.h.  It's a rather large patch but largely
uninteresting -- it's mostly a straightforward conversion from the old
approach to the new one.

The main benefit of this change is that it introduces type safety to
the gdbarch registry.  It also removes a bunch of code.

One possible drawback is that, previously, the gdbarch registry
differentiated between pre- and post-initialization setup.  This
doesn't seem very important to me, though.

3 files changed, 25 insertions, 48 deletions

diff --git a/gdb/python/py-arch.c b/gdb/python/py-arch.c
index 594e4ed..cf09785 100644
--- a/gdb/python/py-arch.c
+++ b/gdb/python/py-arch.c
@@ -28,7 +28,8 @@ struct arch_object {
   struct gdbarch *gdbarch;
 };
 
-static struct gdbarch_data *arch_object_data = NULL;
+static const registry<gdbarch>::key<PyObject, gdb::noop_deleter<PyObject>>
+     arch_object_data;
 
 /* Require a valid Architecture.  */
 #define ARCHPY_REQUIRE_VALID(arch_obj, arch)			\
@@ -48,7 +49,7 @@ extern PyTypeObject arch_object_type
 /* Associates an arch_object with GDBARCH as gdbarch_data via the gdbarch
    post init registration mechanism (gdbarch_data_register_post_init).  */
 
-static void *
+static PyObject *
 arch_object_data_init (struct gdbarch *gdbarch)
 {
   arch_object *arch_obj = PyObject_New (arch_object, &arch_object_type);
@@ -58,7 +59,7 @@ arch_object_data_init (struct gdbarch *gdbarch)
 
   arch_obj->gdbarch = gdbarch;
 
-  return (void *) arch_obj;
+  return (PyObject *) arch_obj;
 }
 
 /* Returns the struct gdbarch value corresponding to the given Python
@@ -88,10 +89,14 @@ gdbpy_is_architecture (PyObject *obj)
 PyObject *
 gdbarch_to_arch_object (struct gdbarch *gdbarch)
 {
-  PyObject *new_ref = (PyObject *) gdbarch_data (gdbarch, arch_object_data);
+  PyObject *new_ref = arch_object_data.get (gdbarch);
+  if (new_ref == nullptr)
+    {
+      new_ref = arch_object_data_init (gdbarch);
+      arch_object_data.set (gdbarch, new_ref);
+    }
 
-  /* new_ref could be NULL if registration of arch_object with GDBARCH failed
-     in arch_object_data_init.  */
+  /* new_ref could be NULL if creation failed.  */
   Py_XINCREF (new_ref);
 
   return new_ref;
@@ -337,13 +342,6 @@ gdbpy_all_architecture_names (PyObject *self, PyObject *args)
  return list.release ();
 }
 
-void _initialize_py_arch ();
-void
-_initialize_py_arch ()
-{
-  arch_object_data = gdbarch_data_register_post_init (arch_object_data_init);
-}
-
 /* Initializes the Architecture class in the gdb module.  */
 
 int
diff --git a/gdb/python/py-registers.c b/gdb/python/py-registers.c
index bbb322f..f22575a 100644
--- a/gdb/python/py-registers.c
+++ b/gdb/python/py-registers.c
@@ -25,8 +25,12 @@
 #include "user-regs.h"
 #include <unordered_map>
 
+/* Per-gdbarch data type.  */
+typedef std::vector<gdbpy_ref<>> gdbpy_register_type;
+
 /* Token to access per-gdbarch data related to register descriptors.  */
-static struct gdbarch_data *gdbpy_register_object_data = NULL;
+static const registry<gdbarch>::key<gdbpy_register_type>
+     gdbpy_register_object_data;
 
 /* Structure for iterator over register descriptors.  */
 struct register_descriptor_iterator_object {
@@ -85,16 +89,6 @@ struct reggroup_object {
 extern PyTypeObject reggroup_object_type
     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("reggroup_object");
 
-/* Associates a vector of gdb.RegisterDescriptor objects with GDBARCH as
-   gdbarch_data via the gdbarch post init registration mechanism
-   (gdbarch_data_register_post_init).  */
-
-static void *
-gdbpy_register_object_data_init (struct gdbarch *gdbarch)
-{
-  return new std::vector<gdbpy_ref<>>;
-}
-
 /* Return a gdb.RegisterGroup object wrapping REGGROUP.  The register
    group objects are cached, and the same Python object will always be
    returned for the same REGGROUP pointer.  */
@@ -156,9 +150,10 @@ static gdbpy_ref<>
 gdbpy_get_register_descriptor (struct gdbarch *gdbarch,
 			       int regnum)
 {
-  auto &vec
-    = *(std::vector<gdbpy_ref<>> *) gdbarch_data (gdbarch,
-						  gdbpy_register_object_data);
+  gdbpy_register_type *vecp = gdbpy_register_object_data.get (gdbarch);
+  if (vecp == nullptr)
+    vecp = gdbpy_register_object_data.emplace (gdbarch);
+  gdbpy_register_type &vec = *vecp;
 
   /* Ensure that we have enough entries in the vector.  */
   if (vec.size () <= regnum)
@@ -422,14 +417,6 @@ gdbpy_parse_register_id (struct gdbarch *gdbarch, PyObject *pyo_reg_id,
   return false;
 }
 
-void _initialize_py_registers ();
-void
-_initialize_py_registers ()
-{
-  gdbpy_register_object_data
-    = gdbarch_data_register_post_init (gdbpy_register_object_data_init);
-}
-
 /* Initializes the new Python classes from this file in the gdb module.  */
 
 int
diff --git a/gdb/python/py-unwind.c b/gdb/python/py-unwind.c
index b2fd140..fb94661 100644
--- a/gdb/python/py-unwind.c
+++ b/gdb/python/py-unwind.c
@@ -117,8 +117,6 @@ extern PyTypeObject pending_frame_object_type
 extern PyTypeObject unwind_info_object_type
     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("unwind_info_object");
 
-static struct gdbarch_data *pyuw_gdbarch_data;
-
 /* Convert gdb.Value instance to inferior's pointer.  Return 1 on success,
    0 on failure.  */
 
@@ -657,14 +655,10 @@ pyuw_dealloc_cache (struct frame_info *this_frame, void *cache)
 struct pyuw_gdbarch_data_type
 {
   /* Has the unwinder shim been prepended? */
-  int unwinder_registered;
+  int unwinder_registered = 0;
 };
 
-static void *
-pyuw_gdbarch_data_init (struct gdbarch *gdbarch)
-{
-  return GDBARCH_OBSTACK_ZALLOC (gdbarch, struct pyuw_gdbarch_data_type);
-}
+static const registry<gdbarch>::key<pyuw_gdbarch_data_type> pyuw_gdbarch_data;
 
 /* New inferior architecture callback: register the Python unwinders
    intermediary.  */
@@ -672,9 +666,9 @@ pyuw_gdbarch_data_init (struct gdbarch *gdbarch)
 static void
 pyuw_on_new_gdbarch (struct gdbarch *newarch)
 {
-  struct pyuw_gdbarch_data_type *data
-    = (struct pyuw_gdbarch_data_type *) gdbarch_data (newarch,
-						      pyuw_gdbarch_data);
+  struct pyuw_gdbarch_data_type *data = pyuw_gdbarch_data.get (newarch);
+  if (data == nullptr)
+    data= pyuw_gdbarch_data.emplace (newarch);
 
   if (!data->unwinder_registered)
     {
@@ -706,8 +700,6 @@ _initialize_py_unwind ()
 	NULL,
 	show_pyuw_debug,
 	&setdebuglist, &showdebuglist);
-  pyuw_gdbarch_data
-    = gdbarch_data_register_post_init (pyuw_gdbarch_data_init);
 }
 
 /* Initialize unwind machinery.  */