bpo-46765: Replace Locally Cached Strings with Statically Initialized Objects (gh-31366)

https://bugs.python.org/issue46765

4 files changed, 10 insertions, 52 deletions

diff --git a/Objects/boolobject.c b/Objects/boolobject.c
index 53f81926057..d86958aff9c 100644
--- a/Objects/boolobject.c
+++ b/Objects/boolobject.c
@@ -1,26 +1,15 @@
 /* Boolean type, a subtype of int */
 
 #include "Python.h"
+#include "pycore_runtime.h"       // _Py_ID()
 #include "pycore_pyerrors.h"      // _Py_FatalRefcountError()
 
 /* We define bool_repr to return "False" or "True" */
 
-static PyObject *false_str = NULL;
-static PyObject *true_str = NULL;
-
 static PyObject *
 bool_repr(PyObject *self)
 {
-    PyObject *s;
-
-    if (self == Py_True)
-        s = true_str ? true_str :
-            (true_str = PyUnicode_InternFromString("True"));
-    else
-        s = false_str ? false_str :
-            (false_str = PyUnicode_InternFromString("False"));
-    Py_XINCREF(s);
-    return s;
+    return self == Py_True ? &_Py_ID(True) : &_Py_ID(False);
 }
 
 /* Function to return a bool from a C long */
diff --git a/Objects/classobject.c b/Objects/classobject.c
index d7ccf31244e..3b1c25394f1 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -157,13 +157,7 @@ static PyMemberDef method_memberlist[] = {
 static PyObject *
 method_get_doc(PyMethodObject *im, void *context)
 {
-    static PyObject *docstr;
-    if (docstr == NULL) {
-        docstr= PyUnicode_InternFromString("__doc__");
-        if (docstr == NULL)
-            return NULL;
-    }
-    return PyObject_GetAttr(im->im_func, docstr);
+    return PyObject_GetAttr(im->im_func, &_Py_ID(__doc__));
 }
 
 static PyGetSetDef method_getset[] = {
@@ -405,13 +399,8 @@ static PyMemberDef instancemethod_memberlist[] = {
 static PyObject *
 instancemethod_get_doc(PyObject *self, void *context)
 {
-    static PyObject *docstr;
-    if (docstr == NULL) {
-        docstr = PyUnicode_InternFromString("__doc__");
-        if (docstr == NULL)
-            return NULL;
-    }
-    return PyObject_GetAttr(PyInstanceMethod_GET_FUNCTION(self), docstr);
+    return PyObject_GetAttr(PyInstanceMethod_GET_FUNCTION(self),
+                            &_Py_ID(__doc__));
 }
 
 static PyGetSetDef instancemethod_getset[] = {
diff --git a/Objects/codeobject.c b/Objects/codeobject.c
index 9a27f1295b1..f8ef1e6b40c 100644
--- a/Objects/codeobject.c
+++ b/Objects/codeobject.c
@@ -553,16 +553,11 @@ PyCode_New(int argcount, int kwonlyargcount,
 PyCodeObject *
 PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
 {
-    PyObject *emptystring = NULL;
     PyObject *nulltuple = NULL;
     PyObject *filename_ob = NULL;
     PyObject *funcname_ob = NULL;
     PyCodeObject *result = NULL;
 
-    emptystring = PyBytes_FromString("");
-    if (emptystring == NULL) {
-        goto failed;
-    }
     nulltuple = PyTuple_New(0);
     if (nulltuple == NULL) {
         goto failed;
@@ -576,6 +571,7 @@ PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
         goto failed;
     }
 
+#define emptystring (PyObject *)&_Py_SINGLETON(bytes_empty)
     struct _PyCodeConstructor con = {
         .filename = filename_ob,
         .name = funcname_ob,
@@ -594,7 +590,6 @@ PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
     result = _PyCode_New(&con);
 
 failed:
-    Py_XDECREF(emptystring);
     Py_XDECREF(nulltuple);
     Py_XDECREF(funcname_ob);
     Py_XDECREF(filename_ob);
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 1ba1c1b0531..783ae88a17f 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -15,7 +15,7 @@ class list "PyListObject *" "&PyList_Type"
 
 #include "clinic/listobject.c.h"
 
-static PyObject *indexerr = NULL;
+_Py_DECLARE_STR(list_err, "list index out of range");
 
 #if PyList_MAXFREELIST > 0
 static struct _Py_list_state *
@@ -125,10 +125,6 @@ _PyList_Fini(PyInterpreterState *interp)
     struct _Py_list_state *state = &interp->list;
     state->numfree = -1;
 #endif
-
-    if (_Py_IsMainInterpreter(interp)) {
-        Py_CLEAR(indexerr);
-    }
 }
 
 /* Print summary info about the state of the optimized allocator */
@@ -238,13 +234,8 @@ PyList_GetItem(PyObject *op, Py_ssize_t i)
         return NULL;
     }
     if (!valid_index(i, Py_SIZE(op))) {
-        if (indexerr == NULL) {
-            indexerr = PyUnicode_FromString(
-                "list index out of range");
-            if (indexerr == NULL)
-                return NULL;
-        }
-        PyErr_SetObject(PyExc_IndexError, indexerr);
+        _Py_DECLARE_STR(list_err, "list index out of range");
+        PyErr_SetObject(PyExc_IndexError, &_Py_STR(list_err));
         return NULL;
     }
     return ((PyListObject *)op) -> ob_item[i];
@@ -452,13 +443,7 @@ static PyObject *
 list_item(PyListObject *a, Py_ssize_t i)
 {
     if (!valid_index(i, Py_SIZE(a))) {
-        if (indexerr == NULL) {
-            indexerr = PyUnicode_FromString(
-                "list index out of range");
-            if (indexerr == NULL)
-                return NULL;
-        }
-        PyErr_SetObject(PyExc_IndexError, indexerr);
+        PyErr_SetObject(PyExc_IndexError, &_Py_STR(list_err));
         return NULL;
     }
     Py_INCREF(a->ob_item[i]);