gh-160725: Speed up print() by looking up write() once per call

Look up the file's write() method once per print() call, instead of once
for each argument, separator and line ending, and pass the cached ' ' and
'\n' strings for the default sep and end directly, instead of converting
them from C strings with PyFile_WriteString().  write() is called exactly
as before.

print() is up to 1.66x faster in pyperf benchmarks, 1.20x geometric
mean; for example, print('a', 1, 2.5) to a file goes from 996 ns to
687 ns.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0129ST3GmU89AvSnUNSXu2Yi

Author: cmaloney

Misc/NEWS.d/next/Core_and_Builtins/2026-10-26-04-00-00.gh-issue-160725.pRnT8w.rst

@@ -0,0 +1,2 @@
+Speed up :func:`print` by looking up the file's ``write()`` method once per
+call.

Python/bltinmodule.c

@@ -2241,6 +2241,23 @@ builtin_pow_impl(PyObject *module, PyObject *base, PyObject *exp,
     return PyNumber_Power(base, exp, mod);
 }
 
+/* Write str(obj) by calling write. */
+static int
+print_write(PyObject *write, PyObject *obj)
+{
+    PyObject *str = PyObject_Str(obj);
+    if (str == NULL) {
+        return -1;
+    }
+    PyObject *result = PyObject_CallOneArg(write, str);
+    Py_DECREF(str);
+    if (result == NULL) {
+        return -1;
+    }
+    Py_DECREF(result);
+    return 0;
+}
+
 /*[clinic input]
 print as builtin_print
 
@@ -2264,7 +2281,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
                    PyObject *file, int flush)
 /*[clinic end generated code: output=38d8def56c837bcc input=ff35cb3d59ee8115]*/
 {
-    int i, err;
+    int i;
 
     if (file == Py_None) {
         file = PySys_GetAttr(&_Py_ID(stdout));
@@ -2283,7 +2300,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
     }
 
     if (sep == Py_None) {
-        sep = NULL;
+        sep = _Py_LATIN1_CHR(' ');
     }
     else if (sep && !PyUnicode_Check(sep)) {
         PyErr_Format(PyExc_TypeError,
@@ -2293,7 +2310,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
         return NULL;
     }
     if (end == Py_None) {
-        end = NULL;
+        end = _Py_LATIN1_CHR('\n');
     }
     else if (end && !PyUnicode_Check(end)) {
         PyErr_Format(PyExc_TypeError,
@@ -2303,36 +2320,23 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
         return NULL;
     }
 
+    PyObject *write = PyObject_GetAttr(file, &_Py_ID(write));
+    if (write == NULL) {
+        Py_DECREF(file);
+        return NULL;
+    }
     for (i = 0; i < objects_length; i++) {
-        if (i > 0) {
-            if (sep == NULL) {
-                err = PyFile_WriteString(" ", file);
-            }
-            else {
-                err = PyFile_WriteObject(sep, file, Py_PRINT_RAW);
-            }
-            if (err) {
-                Py_DECREF(file);
-                return NULL;
-            }
+        if (i > 0 && print_write(write, sep) < 0) {
+            goto error;
         }
-        err = PyFile_WriteObject(objects[i], file, Py_PRINT_RAW);
-        if (err) {
-            Py_DECREF(file);
-            return NULL;
+        if (print_write(write, objects[i]) < 0) {
+            goto error;
         }
     }
-
-    if (end == NULL) {
-        err = PyFile_WriteString("\n", file);
-    }
-    else {
-        err = PyFile_WriteObject(end, file, Py_PRINT_RAW);
-    }
-    if (err) {
-        Py_DECREF(file);
-        return NULL;
+    if (print_write(write, end) < 0) {
+        goto error;
     }
+    Py_DECREF(write);
 
     if (flush) {
         if (_PyFile_Flush(file) < 0) {
@@ -2343,6 +2347,11 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
     Py_DECREF(file);
 
     Py_RETURN_NONE;
+
+error:
+    Py_DECREF(write);
+    Py_DECREF(file);
+    return NULL;
 }