[RFC 6/9] gdb/python: convert gdb.Symbol to use gdbpy_registry

Jan Vrany
2025-01-27T10:49:32Z

This commit converts gdb.Symbol to use gdbpy_registry for lifecycle
management. Since gdb.Symbol only holds on the struct symbol * (and
prev/next links) the default invalidator can be used.
---
gdb/python/py-symbol.c | 91 +++++-------------------------------------
1 file changed, 9 insertions(+), 82 deletions(-)

diff --git a/gdb/python/py-symbol.c b/gdb/python/py-symbol.c
index c157bd7f5d7..f891c5619d6 100644
--- a/gdb/python/py-symbol.c
+++ b/gdb/python/py-symbol.c
@@ -29,12 +29,6 @@ struct symbol_object {
PyObject_HEAD
/* The GDB symbol structure this object is wrapping. */
struct symbol *symbol;
- /* A symbol object is associated with an objfile, so keep track with
- doubly-linked list, rooted in the objfile. This lets us
- invalidate the underlying struct symbol when the objfile is
- deleted. */
- symbol_object *prev;
- symbol_object *next;
};

/* Require a valid symbol. All access to symbol_object->symbol should be
@@ -50,28 +44,8 @@ struct symbol_object {
} \
} while (0)

-/* A deleter that is used when an objfile is about to be freed. */
-struct symbol_object_deleter
-{
- void operator() (symbol_object *obj)
- {
- while (obj)
- {
- symbol_object *next = obj->next;
-
- obj->symbol = NULL;
- obj->next = NULL;
- obj->prev = NULL;
-
- obj = next;
- }
- }
-};
-
-static const registry<objfile>::key<symbol_object, symbol_object_deleter>
- sympy_objfile_data_key;
-static const registry<gdbarch>::key<symbol_object, symbol_object_deleter>
- sympy_gdbarch_data_key;
+static const gdbpy_registry<gdbpy_memoizing_registry_storage<symbol_object, symbol, &symbol_object::symbol>>
+ sympy_registry;

static PyObject *
sympy_str (PyObject *self)
@@ -336,28 +310,17 @@ static void
set_symbol (symbol_object *obj, struct symbol *symbol)
{
obj->symbol = symbol;
- obj->prev = nullptr;
if (symbol->is_objfile_owned ())
{
/* Can it really happen that symbol->symtab () is NULL? */
if (symbol->symtab () != nullptr)
{
- struct objfile *objfile = symbol->objfile ();
-
- obj->next = sympy_objfile_data_key.get (objfile);
- if (obj->next)
- obj->next->prev = obj;
- sympy_objfile_data_key.set (objfile, obj);
+ sympy_registry.add (symbol->objfile (), obj);
}
}
else
{
- struct gdbarch *arch = symbol->arch ();
-
- obj->next = sympy_gdbarch_data_key.get (arch);
- if (obj->next)
- obj->next->prev = obj;
- sympy_gdbarch_data_key.set (arch, obj);
+ sympy_registry.add (symbol->arch (), obj);
}
}

@@ -371,19 +334,11 @@ symbol_to_symbol_object (struct symbol *sym)
/* Look if there's already a gdb.Symbol object for given SYMBOL
and if so, return it. */
if (sym->is_objfile_owned ())
- sym_obj = sympy_objfile_data_key.get (sym->objfile ());
+ sym_obj = sympy_registry.lookup (sym->objfile (), sym);
else
- sym_obj = sympy_gdbarch_data_key.get (sym->arch ());
-
- while (sym_obj != nullptr)
- {
- if (sym_obj->symbol == sym)
- {
- Py_INCREF (sym_obj);
- return (PyObject*)sym_obj;
- }
- sym_obj = sym_obj->next;
- }
+ sym_obj = sympy_registry.lookup (sym->arch (), sym);
+ if (sym_obj != nullptr)
+ return (PyObject*)sym_obj;

sym_obj = PyObject_New (symbol_object, &symbol_object_type);
if (sym_obj)
@@ -401,34 +356,6 @@ symbol_object_to_symbol (PyObject *obj)
return ((symbol_object *) obj)->symbol;
}

-static void
-sympy_dealloc (PyObject *obj)
-{
- symbol_object *sym_obj = (symbol_object *) obj;
-
- if (sym_obj->prev)
- sym_obj->prev->next = sym_obj->next;
- else if (sym_obj->symbol != nullptr)
- {
- if (sym_obj->symbol->is_objfile_owned ())
- {
- /* Can it really happen that symbol->symtab () is NULL? */
- if (sym_obj->symbol->symtab () != nullptr)
- sympy_objfile_data_key.set (sym_obj->symbol->objfile (),
- sym_obj->next);
- }
- else
- {
- sympy_gdbarch_data_key.set (sym_obj->symbol->arch (),
- sym_obj->next);
- }
- }
- if (sym_obj->next)
- sym_obj->next->prev = sym_obj->prev;
- sym_obj->symbol = NULL;
- Py_TYPE (obj)->tp_free (obj);
-}
-
/* __repr__ implementation for gdb.Symbol. */

static PyObject *
@@ -791,7 +718,7 @@ PyTypeObject symbol_object_type = {
"gdb.Symbol", /*tp_name*/
sizeof (symbol_object), /*tp_basicsize*/
0, /*tp_itemsize*/
- sympy_dealloc, /*tp_dealloc*/
+ 0, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
--
2.45.2