GH-101291: Rearrange the size bits in PyLongObject (GH-102464)

* Eliminate all remaining uses of Py_SIZE and Py_SET_SIZE on PyLongObject, adding asserts.

* Change layout of size/sign bits in longobject to support future addition of immortal ints and tagged medium ints.

* Add functions to hide some internals of long object, and for setting sign and digit count.

* Replace uses of IS_MEDIUM_VALUE macro with _PyLong_IsCompact().

1 files changed, 7 insertions, 2 deletions

diff --git a/Objects/boolobject.c b/Objects/boolobject.c
index a035f46..9d8e956 100644
--- a/Objects/boolobject.c
+++ b/Objects/boolobject.c
@@ -2,6 +2,7 @@
 
 #include "Python.h"
 #include "pycore_object.h"      // _Py_FatalRefcountError()
+#include "pycore_long.h"        // FALSE_TAG TRUE_TAG
 #include "pycore_runtime.h"       // _Py_ID()
 
 #include <stddef.h>
@@ -198,10 +199,14 @@ PyTypeObject PyBool_Type = {
 
 struct _longobject _Py_FalseStruct = {
     PyObject_HEAD_INIT(&PyBool_Type)
-    { 0, { 0 } }
+    { .lv_tag = _PyLong_FALSE_TAG,
+        { 0 }
+    }
 };
 
 struct _longobject _Py_TrueStruct = {
     PyObject_HEAD_INIT(&PyBool_Type)
-    { 1, { 1 } }
+    { .lv_tag = _PyLong_TRUE_TAG,
+        { 1 }
+    }
 };