From: Victor Stinner <victor.stinner@gmail.com>
Date: Mon, 28 Nov 2016 17:32:31 +0000 (+0100)
Subject: call_function(): document PyMethod optimization
X-Git-Tag: v3.7.0a1~1869
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b69ee8c38642a4efd0b880f0c8651010aa7883b9;p=python

call_function(): document PyMethod optimization
---

diff --git a/Python/ceval.c b/Python/ceval.c
index 569c609979..42c0c614b1 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4736,7 +4736,11 @@ call_function(PyObject ***pp_stack, Py_ssize_t oparg, PyObject *kwnames)
     }
     else {
         if (PyMethod_Check(func) && PyMethod_GET_SELF(func) != NULL) {
-            /* optimize access to bound methods */
+            /* Optimize access to bound methods. Reuse the Python stack
+               to pass 'self' as the first argument, replace 'func'
+               with 'self'. It avoids the creation of a new temporary tuple
+               for arguments (to replace func with self) when the method uses
+               FASTCALL. */
             PyObject *self = PyMethod_GET_SELF(func);
             Py_INCREF(self);
             func = PyMethod_GET_FUNCTION(func);