gh-127274: Defer nested methods (#128012)

Methods (functions defined in class scope) are likely to be cleaned
up by the GC anyway.

Add a new code flag, `CO_METHOD`, that is set for functions defined
in a class scope. Use that when deciding to defer functions.

2 files changed, 9 insertions, 0 deletions

diff --git a/Python/compile.c b/Python/compile.c
index cbfba7f..ef47083 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1289,6 +1289,8 @@ compute_code_flags(compiler *c)
             flags |= CO_VARKEYWORDS;
         if (ste->ste_has_docstring)
             flags |= CO_HAS_DOCSTRING;
+        if (ste->ste_method)
+            flags |= CO_METHOD;
     }
 
     if (ste->ste_coroutine && !ste->ste_generator) {
diff --git a/Python/symtable.c b/Python/symtable.c
index ebddb0b..49bd01b 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -138,6 +138,13 @@ ste_new(struct symtable *st, identifier name, _Py_block_ty block,
 
     ste->ste_has_docstring = 0;
 
+    ste->ste_method = 0;
+    if (st->st_cur != NULL &&
+        st->st_cur->ste_type == ClassBlock &&
+        block == FunctionBlock) {
+        ste->ste_method = 1;
+    }
+
     ste->ste_symbols = PyDict_New();
     ste->ste_varnames = PyList_New(0);
     ste->ste_children = PyList_New(0);