codeobject.c

#include <stdbool.h>

#include "Python.h"
#include "opcode.h"
#include "structmember.h"         // PyMemberDef
#include "pycore_code.h"          // _PyCodeConstructor
#include "pycore_interp.h"        // PyInterpreterState.co_extra_freefuncs
#include "pycore_opcode.h"        // _PyOpcode_Deopt
#include "pycore_pystate.h"       // _PyInterpreterState_GET()
#include "pycore_tuple.h"         // _PyTuple_ITEMS()
#include "clinic/codeobject.c.h"


/******************
 * generic helpers
 ******************/

/* all_name_chars(s): true iff s matches [a-zA-Z0-9_]* */
static int
all_name_chars(PyObject *o)
{
    const unsigned char *s, *e;

    if (!PyUnicode_IS_ASCII(o))
        return 0;

    s = PyUnicode_1BYTE_DATA(o);
    e = s + PyUnicode_GET_LENGTH(o);
    for (; s != e; s++) {
        if (!Py_ISALNUM(*s) && *s != '_')
            return 0;
    }
    return 1;
}

static int
intern_strings(PyObject *tuple)
{
    Py_ssize_t i;

    for (i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {
        PyObject *v = PyTuple_GET_ITEM(tuple, i);
        if (v == NULL || !PyUnicode_CheckExact(v)) {
            PyErr_SetString(PyExc_SystemError,
                            "non-string found in code slot");
            return -1;
        }
        PyUnicode_InternInPlace(&_PyTuple_ITEMS(tuple)[i]);
    }
    return 0;
}

/* Intern selected string constants */
static int
intern_string_constants(PyObject *tuple, int *modified)
{
    for (Py_ssize_t i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {
        PyObject *v = PyTuple_GET_ITEM(tuple, i);
        if (PyUnicode_CheckExact(v)) {
            if (PyUnicode_READY(v) == -1) {
                return -1;
            }

            if (all_name_chars(v)) {
                PyObject *w = v;
                PyUnicode_InternInPlace(&v);
                if (w != v) {
                    PyTuple_SET_ITEM(tuple, i, v);
                    if (modified) {
                        *modified = 1;