Library import 16 (#2433)

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1 files changed, 2429 insertions, 0 deletions

diff --git a/contrib/tools/python3/Objects/codeobject.c b/contrib/tools/python3/Objects/codeobject.c
new file mode 100644
index 0000000000..5e358825d8
--- /dev/null
+++ b/contrib/tools/python3/Objects/codeobject.c
@@ -0,0 +1,2429 @@
+#include <stdbool.h>
+
+#include "Python.h"
+#include "opcode.h"
+#include "structmember.h"         // PyMemberDef
+#include "pycore_code.h"          // _PyCodeConstructor
+#include "pycore_frame.h"         // FRAME_SPECIALS_SIZE
+#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"
+
+static PyObject* code_repr(PyCodeObject *co);
+
+static const char *
+code_event_name(PyCodeEvent event) {
+    switch (event) {
+        #define CASE(op)                \
+        case PY_CODE_EVENT_##op:         \
+            return "PY_CODE_EVENT_" #op;
+        PY_FOREACH_CODE_EVENT(CASE)
+        #undef CASE
+    }
+    Py_UNREACHABLE();
+}
+
+static void
+notify_code_watchers(PyCodeEvent event, PyCodeObject *co)
+{
+    assert(Py_REFCNT(co) > 0);
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    assert(interp->_initialized);
+    uint8_t bits = interp->active_code_watchers;
+    int i = 0;
+    while (bits) {
+        assert(i < CODE_MAX_WATCHERS);
+        if (bits & 1) {
+            PyCode_WatchCallback cb = interp->code_watchers[i];
+            // callback must be non-null if the watcher bit is set
+            assert(cb != NULL);
+            if (cb(event, co) < 0) {
+                // Don't risk resurrecting the object if an unraisablehook keeps
+                // a reference; pass a string as context.
+                PyObject *context = NULL;
+                PyObject *repr = code_repr(co);
+                if (repr) {
+                    context = PyUnicode_FromFormat(
+                        "%s watcher callback for %U",
+                        code_event_name(event), repr);
+                    Py_DECREF(repr);
+                }
+                if (context == NULL) {
+                    context = Py_NewRef(Py_None);
+                }
+                PyErr_WriteUnraisable(context);
+                Py_DECREF(context);
+            }
+        }
+        i++;
+        bits >>= 1;
+    }
+}
+
+int
+PyCode_AddWatcher(PyCode_WatchCallback callback)
+{
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    assert(interp->_initialized);
+
+    for (int i = 0; i < CODE_MAX_WATCHERS; i++) {
+        if (!interp->code_watchers[i]) {
+            interp->code_watchers[i] = callback;
+            interp->active_code_watchers |= (1 << i);
+            return i;
+        }
+    }
+
+    PyErr_SetString(PyExc_RuntimeError, "no more code watcher IDs available");
+    return -1;
+}
+
+static inline int
+validate_watcher_id(PyInterpreterState *interp, int watcher_id)
+{
+    if (watcher_id < 0 || watcher_id >= CODE_MAX_WATCHERS) {
+        PyErr_Format(PyExc_ValueError, "Invalid code watcher ID %d", watcher_id);
+        return -1;
+    }
+    if (!interp->code_watchers[watcher_id]) {
+        PyErr_Format(PyExc_ValueError, "No code watcher set for ID %d", watcher_id);
+        return -1;
+    }
+    return 0;
+}
+
+int
+PyCode_ClearWatcher(int watcher_id)
+{
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    assert(interp->_initialized);
+    if (validate_watcher_id(interp, watcher_id) < 0) {
+        return -1;
+    }
+    interp->code_watchers[watcher_id] = NULL;
+    interp->active_code_watchers &= ~(1 << watcher_id);
+    return 0;
+}
+
+/******************
+ * 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;
+                    }
+                }
+            }
+        }
+        else if (PyTuple_CheckExact(v)) {
+            if (intern_string_constants(v, NULL) < 0) {
+                return -1;
+            }
+        }
+        else if (PyFrozenSet_CheckExact(v)) {
+            PyObject *w = v;
+            PyObject *tmp = PySequence_Tuple(v);
+            if (tmp == NULL) {
+                return -1;
+            }
+            int tmp_modified = 0;
+            if (intern_string_constants(tmp, &tmp_modified) < 0) {
+                Py_DECREF(tmp);
+                return -1;
+            }
+            if (tmp_modified) {
+                v = PyFrozenSet_New(tmp);
+                if (v == NULL) {
+                    Py_DECREF(tmp);
+                    return -1;
+                }
+
+                PyTuple_SET_ITEM(tuple, i, v);
+                Py_DECREF(w);
+                if (modified) {
+                    *modified = 1;
+                }
+            }
+            Py_DECREF(tmp);
+        }
+    }
+    return 0;
+}
+
+/* Return a shallow copy of a tuple that is
+   guaranteed to contain exact strings, by converting string subclasses
+   to exact strings and complaining if a non-string is found. */
+static PyObject*
+validate_and_copy_tuple(PyObject *tup)
+{
+    PyObject *newtuple;
+    PyObject *item;
+    Py_ssize_t i, len;
+
+    len = PyTuple_GET_SIZE(tup);
+    newtuple = PyTuple_New(len);
+    if (newtuple == NULL)
+        return NULL;
+
+    for (i = 0; i < len; i++) {
+        item = PyTuple_GET_ITEM(tup, i);
+        if (PyUnicode_CheckExact(item)) {
+            Py_INCREF(item);
+        }
+        else if (!PyUnicode_Check(item)) {
+            PyErr_Format(
+                PyExc_TypeError,
+                "name tuples must contain only "
+                "strings, not '%.500s'",
+                Py_TYPE(item)->tp_name);
+            Py_DECREF(newtuple);
+            return NULL;
+        }
+        else {
+            item = _PyUnicode_Copy(item);
+            if (item == NULL) {
+                Py_DECREF(newtuple);
+                return NULL;
+            }
+        }
+        PyTuple_SET_ITEM(newtuple, i, item);
+    }
+
+    return newtuple;
+}
+
+static int
+init_co_cached(PyCodeObject *self) {
+    if (self->_co_cached == NULL) {
+        self->_co_cached = PyMem_New(_PyCoCached, 1);
+        if (self->_co_cached == NULL) {
+            PyErr_NoMemory();
+            return -1;
+        }
+        self->_co_cached->_co_code = NULL;
+        self->_co_cached->_co_cellvars = NULL;
+        self->_co_cached->_co_freevars = NULL;
+        self->_co_cached->_co_varnames = NULL;
+    }
+    return 0;
+
+}
+/******************
+ * _PyCode_New()
+ ******************/
+
+// This is also used in compile.c.
+void
+_Py_set_localsplus_info(int offset, PyObject *name, _PyLocals_Kind kind,
+                        PyObject *names, PyObject *kinds)
+{
+    PyTuple_SET_ITEM(names, offset, Py_NewRef(name));
+    _PyLocals_SetKind(kinds, offset, kind);
+}
+
+static void
+get_localsplus_counts(PyObject *names, PyObject *kinds,
+                      int *pnlocals, int *pncellvars,
+                      int *pnfreevars)
+{
+    int nlocals = 0;
+    int ncellvars = 0;
+    int nfreevars = 0;
+    Py_ssize_t nlocalsplus = PyTuple_GET_SIZE(names);
+    for (int i = 0; i < nlocalsplus; i++) {
+        _PyLocals_Kind kind = _PyLocals_GetKind(kinds, i);
+        if (kind & CO_FAST_LOCAL) {
+            nlocals += 1;
+            if (kind & CO_FAST_CELL) {
+                ncellvars += 1;
+            }
+        }
+        else if (kind & CO_FAST_CELL) {
+            ncellvars += 1;
+        }
+        else if (kind & CO_FAST_FREE) {
+            nfreevars += 1;
+        }
+    }
+    if (pnlocals != NULL) {
+        *pnlocals = nlocals;
+    }
+    if (pncellvars != NULL) {
+        *pncellvars = ncellvars;
+    }
+    if (pnfreevars != NULL) {
+        *pnfreevars = nfreevars;
+    }
+}
+
+static PyObject *
+get_localsplus_names(PyCodeObject *co, _PyLocals_Kind kind, int num)
+{
+    PyObject *names = PyTuple_New(num);
+    if (names == NULL) {
+        return NULL;
+    }
+    int index = 0;
+    for (int offset = 0; offset < co->co_nlocalsplus; offset++) {
+        _PyLocals_Kind k = _PyLocals_GetKind(co->co_localspluskinds, offset);
+        if ((k & kind) == 0) {
+            continue;
+        }
+        assert(index < num);
+        PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, offset);
+        PyTuple_SET_ITEM(names, index, Py_NewRef(name));
+        index += 1;
+    }
+    assert(index == num);
+    return names;
+}
+
+int
+_PyCode_Validate(struct _PyCodeConstructor *con)
+{
+    /* Check argument types */
+    if (con->argcount < con->posonlyargcount || con->posonlyargcount < 0 ||
+        con->kwonlyargcount < 0 ||
+        con->stacksize < 0 || con->flags < 0 ||
+        con->code == NULL || !PyBytes_Check(con->code) ||
+        con->consts == NULL || !PyTuple_Check(con->consts) ||
+        con->names == NULL || !PyTuple_Check(con->names) ||
+        con->localsplusnames == NULL || !PyTuple_Check(con->localsplusnames) ||
+        con->localspluskinds == NULL || !PyBytes_Check(con->localspluskinds) ||
+        PyTuple_GET_SIZE(con->localsplusnames)
+            != PyBytes_GET_SIZE(con->localspluskinds) ||
+        con->name == NULL || !PyUnicode_Check(con->name) ||
+        con->qualname == NULL || !PyUnicode_Check(con->qualname) ||
+        con->filename == NULL || !PyUnicode_Check(con->filename) ||
+        con->linetable == NULL || !PyBytes_Check(con->linetable) ||
+        con->exceptiontable == NULL || !PyBytes_Check(con->exceptiontable)
+        ) {
+        PyErr_BadInternalCall();
+        return -1;
+    }
+
+    /* Make sure that code is indexable with an int, this is
+       a long running assumption in ceval.c and many parts of
+       the interpreter. */
+    if (PyBytes_GET_SIZE(con->code) > INT_MAX) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "code: co_code larger than INT_MAX");
+        return -1;
+    }
+    if (PyBytes_GET_SIZE(con->code) % sizeof(_Py_CODEUNIT) != 0 ||
+        !_Py_IS_ALIGNED(PyBytes_AS_STRING(con->code), sizeof(_Py_CODEUNIT))
+        ) {
+        PyErr_SetString(PyExc_ValueError, "code: co_code is malformed");
+        return -1;
+    }
+
+    /* Ensure that the co_varnames has enough names to cover the arg counts.
+     * Note that totalargs = nlocals - nplainlocals.  We check nplainlocals
+     * here to avoid the possibility of overflow (however remote). */
+    int nlocals;
+    get_localsplus_counts(con->localsplusnames, con->localspluskinds,
+                          &nlocals, NULL, NULL);
+    int nplainlocals = nlocals -
+                       con->argcount -
+                       con->kwonlyargcount -
+                       ((con->flags & CO_VARARGS) != 0) -
+                       ((con->flags & CO_VARKEYWORDS) != 0);
+    if (nplainlocals < 0) {
+        PyErr_SetString(PyExc_ValueError, "code: co_varnames is too small");
+        return -1;
+    }
+
+    return 0;
+}
+
+extern void _PyCode_Quicken(PyCodeObject *code);
+
+static void
+init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
+{
+    int nlocalsplus = (int)PyTuple_GET_SIZE(con->localsplusnames);
+    int nlocals, ncellvars, nfreevars;
+    get_localsplus_counts(con->localsplusnames, con->localspluskinds,
+                          &nlocals, &ncellvars, &nfreevars);
+
+    co->co_filename = Py_NewRef(con->filename);
+    co->co_name = Py_NewRef(con->name);
+    co->co_qualname = Py_NewRef(con->qualname);
+    co->co_flags = con->flags;
+
+    co->co_firstlineno = con->firstlineno;
+    co->co_linetable = Py_NewRef(con->linetable);
+
+    co->co_consts = Py_NewRef(con->consts);
+    co->co_names = Py_NewRef(con->names);
+
+    co->co_localsplusnames = Py_NewRef(con->localsplusnames);
+    co->co_localspluskinds = Py_NewRef(con->localspluskinds);
+
+    co->co_argcount = con->argcount;
+    co->co_posonlyargcount = con->posonlyargcount;
+    co->co_kwonlyargcount = con->kwonlyargcount;
+
+    co->co_stacksize = con->stacksize;
+
+    co->co_exceptiontable = Py_NewRef(con->exceptiontable);
+
+    /* derived values */
+    co->co_nlocalsplus = nlocalsplus;
+    co->co_nlocals = nlocals;
+    co->co_framesize = nlocalsplus + con->stacksize + FRAME_SPECIALS_SIZE;
+    co->co_ncellvars = ncellvars;
+    co->co_nfreevars = nfreevars;
+    co->co_version = _Py_next_func_version;
+    if (_Py_next_func_version != 0) {
+        _Py_next_func_version++;
+    }
+    co->_co_monitoring = NULL;
+    co->_co_instrumentation_version = 0;
+    /* not set */
+    co->co_weakreflist = NULL;
+    co->co_extra = NULL;
+    co->_co_cached = NULL;
+
+    memcpy(_PyCode_CODE(co), PyBytes_AS_STRING(con->code),
+           PyBytes_GET_SIZE(con->code));
+    int entry_point = 0;
+    while (entry_point < Py_SIZE(co) &&
+        _PyCode_CODE(co)[entry_point].op.code != RESUME) {
+        entry_point++;
+    }
+    co->_co_firsttraceable = entry_point;
+    _PyCode_Quicken(co);
+    notify_code_watchers(PY_CODE_EVENT_CREATE, co);
+}
+
+static int
+scan_varint(const uint8_t *ptr)
+{
+    unsigned int read = *ptr++;
+    unsigned int val = read & 63;
+    unsigned int shift = 0;
+    while (read & 64) {
+        read = *ptr++;
+        shift += 6;
+        val |= (read & 63) << shift;
+    }
+    return val;
+}
+
+static int
+scan_signed_varint(const uint8_t *ptr)
+{
+    unsigned int uval = scan_varint(ptr);
+    if (uval & 1) {
+        return -(int)(uval >> 1);
+    }
+    else {
+        return uval >> 1;
+    }
+}
+
+static int
+get_line_delta(const uint8_t *ptr)
+{
+    int code = ((*ptr) >> 3) & 15;
+    switch (code) {
+        case PY_CODE_LOCATION_INFO_NONE:
+            return 0;
+        case PY_CODE_LOCATION_INFO_NO_COLUMNS:
+        case PY_CODE_LOCATION_INFO_LONG:
+            return scan_signed_varint(ptr+1);
+        case PY_CODE_LOCATION_INFO_ONE_LINE0:
+            return 0;
+        case PY_CODE_LOCATION_INFO_ONE_LINE1:
+            return 1;
+        case PY_CODE_LOCATION_INFO_ONE_LINE2:
+            return 2;
+        default:
+            /* Same line */
+            return 0;
+    }
+}
+
+static PyObject *
+remove_column_info(PyObject *locations)
+{
+    int offset = 0;
+    const uint8_t *data = (const uint8_t *)PyBytes_AS_STRING(locations);
+    PyObject *res = PyBytes_FromStringAndSize(NULL, 32);
+    if (res == NULL) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+    uint8_t *output = (uint8_t *)PyBytes_AS_STRING(res);
+    while (offset < PyBytes_GET_SIZE(locations)) {
+        Py_ssize_t write_offset = output - (uint8_t *)PyBytes_AS_STRING(res);
+        if (write_offset + 16 >= PyBytes_GET_SIZE(res)) {
+            if (_PyBytes_Resize(&res, PyBytes_GET_SIZE(res) * 2) < 0) {
+                return NULL;
+            }
+            output = (uint8_t *)PyBytes_AS_STRING(res) + write_offset;
+        }
+        int code = (data[offset] >> 3) & 15;
+        if (code == PY_CODE_LOCATION_INFO_NONE) {
+            *output++ = data[offset];
+        }
+        else {
+            int blength = (data[offset] & 7)+1;
+            output += write_location_entry_start(
+                output, PY_CODE_LOCATION_INFO_NO_COLUMNS, blength);
+            int ldelta = get_line_delta(&data[offset]);
+            output += write_signed_varint(output, ldelta);
+        }
+        offset++;
+        while (offset < PyBytes_GET_SIZE(locations) &&
+            (data[offset] & 128) == 0) {
+            offset++;
+        }
+    }
+    Py_ssize_t write_offset = output - (uint8_t *)PyBytes_AS_STRING(res);
+    if (_PyBytes_Resize(&res, write_offset)) {
+        return NULL;
+    }
+    return res;
+}
+
+/* The caller is responsible for ensuring that the given data is valid. */
+
+PyCodeObject *
+_PyCode_New(struct _PyCodeConstructor *con)
+{
+    /* Ensure that strings are ready Unicode string */
+    if (PyUnicode_READY(con->name) < 0) {
+        return NULL;
+    }
+    if (PyUnicode_READY(con->qualname) < 0) {
+        return NULL;
+    }
+    if (PyUnicode_READY(con->filename) < 0) {
+        return NULL;
+    }
+
+    if (intern_strings(con->names) < 0) {
+        return NULL;
+    }
+    if (intern_string_constants(con->consts, NULL) < 0) {
+        return NULL;
+    }
+    if (intern_strings(con->localsplusnames) < 0) {
+        return NULL;
+    }
+
+    PyObject *replacement_locations = NULL;
+    // Compact the linetable if we are opted out of debug
+    // ranges.
+    if (!_Py_GetConfig()->code_debug_ranges) {
+        replacement_locations = remove_column_info(con->linetable);
+        if (replacement_locations == NULL) {
+            return NULL;
+        }
+        con->linetable = replacement_locations;
+    }
+
+    Py_ssize_t size = PyBytes_GET_SIZE(con->code) / sizeof(_Py_CODEUNIT);
+    PyCodeObject *co = PyObject_NewVar(PyCodeObject, &PyCode_Type, size);
+    if (co == NULL) {
+        Py_XDECREF(replacement_locations);
+        PyErr_NoMemory();
+        return NULL;
+    }
+    init_code(co, con);
+    Py_XDECREF(replacement_locations);
+    return co;
+}
+
+
+/******************
+ * the legacy "constructors"
+ ******************/
+
+PyCodeObject *
+PyUnstable_Code_NewWithPosOnlyArgs(
+                          int argcount, int posonlyargcount, int kwonlyargcount,
+                          int nlocals, int stacksize, int flags,
+                          PyObject *code, PyObject *consts, PyObject *names,
+                          PyObject *varnames, PyObject *freevars, PyObject *cellvars,
+                          PyObject *filename, PyObject *name,
+                          PyObject *qualname, int firstlineno,
+                          PyObject *linetable,
+                          PyObject *exceptiontable)
+{
+    PyCodeObject *co = NULL;
+    PyObject *localsplusnames = NULL;
+    PyObject *localspluskinds = NULL;
+
+    if (varnames == NULL || !PyTuple_Check(varnames) ||
+        cellvars == NULL || !PyTuple_Check(cellvars) ||
+        freevars == NULL || !PyTuple_Check(freevars)
+        ) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+
+    // Set the "fast locals plus" info.
+    int nvarnames = (int)PyTuple_GET_SIZE(varnames);
+    int ncellvars = (int)PyTuple_GET_SIZE(cellvars);
+    int nfreevars = (int)PyTuple_GET_SIZE(freevars);
+    int nlocalsplus = nvarnames + ncellvars + nfreevars;
+    localsplusnames = PyTuple_New(nlocalsplus);
+    if (localsplusnames == NULL) {
+        goto error;
+    }
+    localspluskinds = PyBytes_FromStringAndSize(NULL, nlocalsplus);
+    if (localspluskinds == NULL) {
+        goto error;
+    }
+    int  offset = 0;
+    for (int i = 0; i < nvarnames; i++, offset++) {
+        PyObject *name = PyTuple_GET_ITEM(varnames, i);
+        _Py_set_localsplus_info(offset, name, CO_FAST_LOCAL,
+                               localsplusnames, localspluskinds);
+    }
+    for (int i = 0; i < ncellvars; i++, offset++) {
+        PyObject *name = PyTuple_GET_ITEM(cellvars, i);
+        int argoffset = -1;
+        for (int j = 0; j < nvarnames; j++) {
+            int cmp = PyUnicode_Compare(PyTuple_GET_ITEM(varnames, j),
+                                        name);
+            assert(!PyErr_Occurred());
+            if (cmp == 0) {
+                argoffset = j;
+                break;
+            }
+        }
+        if (argoffset >= 0) {
+            // Merge the localsplus indices.
+            nlocalsplus -= 1;
+            offset -= 1;
+            _PyLocals_Kind kind = _PyLocals_GetKind(localspluskinds, argoffset);
+            _PyLocals_SetKind(localspluskinds, argoffset, kind | CO_FAST_CELL);
+            continue;
+        }
+        _Py_set_localsplus_info(offset, name, CO_FAST_CELL,
+                               localsplusnames, localspluskinds);
+    }
+    for (int i = 0; i < nfreevars; i++, offset++) {
+        PyObject *name = PyTuple_GET_ITEM(freevars, i);
+        _Py_set_localsplus_info(offset, name, CO_FAST_FREE,
+                               localsplusnames, localspluskinds);
+    }
+
+    // gh-110543: Make sure the CO_FAST_HIDDEN flag is set correctly.
+    if (!(flags & CO_OPTIMIZED)) {
+        Py_ssize_t code_len = PyBytes_GET_SIZE(code);
+        _Py_CODEUNIT *code_data = (_Py_CODEUNIT *)PyBytes_AS_STRING(code);
+        Py_ssize_t num_code_units = code_len / sizeof(_Py_CODEUNIT);
+        int extended_arg = 0;
+        for (int i = 0; i < num_code_units; i += 1 + _PyOpcode_Caches[code_data[i].op.code]) {
+            _Py_CODEUNIT *instr = &code_data[i];
+            uint8_t opcode = instr->op.code;
+            if (opcode == EXTENDED_ARG) {
+                extended_arg = extended_arg << 8 | instr->op.arg;
+                continue;
+            }
+            if (opcode == LOAD_FAST_AND_CLEAR) {
+                int oparg = extended_arg << 8 | instr->op.arg;
+                if (oparg >= nlocalsplus) {
+                    PyErr_Format(PyExc_ValueError,
+                                "code: LOAD_FAST_AND_CLEAR oparg %d out of range",
+                                oparg);
+                    goto error;
+                }
+                _PyLocals_Kind kind = _PyLocals_GetKind(localspluskinds, oparg);
+                _PyLocals_SetKind(localspluskinds, oparg, kind | CO_FAST_HIDDEN);
+            }
+            extended_arg = 0;
+        }
+    }
+
+    // If any cells were args then nlocalsplus will have shrunk.
+    if (nlocalsplus != PyTuple_GET_SIZE(localsplusnames)) {
+        if (_PyTuple_Resize(&localsplusnames, nlocalsplus) < 0
+                || _PyBytes_Resize(&localspluskinds, nlocalsplus) < 0) {
+            goto error;
+        }
+    }
+
+    struct _PyCodeConstructor con = {
+        .filename = filename,
+        .name = name,
+        .qualname = qualname,
+        .flags = flags,
+
+        .code = code,
+        .firstlineno = firstlineno,
+        .linetable = linetable,
+
+        .consts = consts,
+        .names = names,
+
+        .localsplusnames = localsplusnames,
+        .localspluskinds = localspluskinds,
+
+        .argcount = argcount,
+        .posonlyargcount = posonlyargcount,
+        .kwonlyargcount = kwonlyargcount,
+
+        .stacksize = stacksize,
+
+        .exceptiontable = exceptiontable,
+    };
+
+    if (_PyCode_Validate(&con) < 0) {
+        goto error;
+    }
+    assert(PyBytes_GET_SIZE(code) % sizeof(_Py_CODEUNIT) == 0);
+    assert(_Py_IS_ALIGNED(PyBytes_AS_STRING(code), sizeof(_Py_CODEUNIT)));
+    if (nlocals != PyTuple_GET_SIZE(varnames)) {
+        PyErr_SetString(PyExc_ValueError,
+                        "code: co_nlocals != len(co_varnames)");
+        goto error;
+    }
+
+    co = _PyCode_New(&con);
+    if (co == NULL) {
+        goto error;
+    }
+
+error:
+    Py_XDECREF(localsplusnames);
+    Py_XDECREF(localspluskinds);
+    return co;
+}
+
+PyCodeObject *
+PyUnstable_Code_New(int argcount, int kwonlyargcount,
+           int nlocals, int stacksize, int flags,
+           PyObject *code, PyObject *consts, PyObject *names,
+           PyObject *varnames, PyObject *freevars, PyObject *cellvars,
+           PyObject *filename, PyObject *name, PyObject *qualname,
+           int firstlineno,
+           PyObject *linetable,
+           PyObject *exceptiontable)
+{
+    return PyCode_NewWithPosOnlyArgs(argcount, 0, kwonlyargcount, nlocals,
+                                     stacksize, flags, code, consts, names,
+                                     varnames, freevars, cellvars, filename,
+                                     name, qualname, firstlineno,
+                                     linetable,
+                                     exceptiontable);
+}
+
+// NOTE: When modifying the construction of PyCode_NewEmpty, please also change
+// test.test_code.CodeLocationTest.test_code_new_empty to keep it in sync!
+
+static const uint8_t assert0[6] = {
+    RESUME, 0,
+    LOAD_ASSERTION_ERROR, 0,
+    RAISE_VARARGS, 1
+};
+
+static const uint8_t linetable[2] = {
+    (1 << 7)  // New entry.
+    | (PY_CODE_LOCATION_INFO_NO_COLUMNS << 3)
+    | (3 - 1),  // Three code units.
+    0,  // Offset from co_firstlineno.
+};
+
+PyCodeObject *
+PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
+{
+    PyObject *nulltuple = NULL;
+    PyObject *filename_ob = NULL;
+    PyObject *funcname_ob = NULL;
+    PyObject *code_ob = NULL;
+    PyObject *linetable_ob = NULL;
+    PyCodeObject *result = NULL;
+
+    nulltuple = PyTuple_New(0);
+    if (nulltuple == NULL) {
+        goto failed;
+    }
+    funcname_ob = PyUnicode_FromString(funcname);
+    if (funcname_ob == NULL) {
+        goto failed;
+    }
+    filename_ob = PyUnicode_DecodeFSDefault(filename);
+    if (filename_ob == NULL) {
+        goto failed;
+    }
+    code_ob = PyBytes_FromStringAndSize((const char *)assert0, 6);
+    if (code_ob == NULL) {
+        goto failed;
+    }
+    linetable_ob = PyBytes_FromStringAndSize((const char *)linetable, 2);
+    if (linetable_ob == NULL) {
+        goto failed;
+    }
+
+#define emptystring (PyObject *)&_Py_SINGLETON(bytes_empty)
+    struct _PyCodeConstructor con = {
+        .filename = filename_ob,
+        .name = funcname_ob,
+        .qualname = funcname_ob,
+        .code = code_ob,
+        .firstlineno = firstlineno,
+        .linetable = linetable_ob,
+        .consts = nulltuple,
+        .names = nulltuple,
+        .localsplusnames = nulltuple,
+        .localspluskinds = emptystring,
+        .exceptiontable = emptystring,
+        .stacksize = 1,
+    };
+    result = _PyCode_New(&con);
+
+failed:
+    Py_XDECREF(nulltuple);
+    Py_XDECREF(funcname_ob);
+    Py_XDECREF(filename_ob);
+    Py_XDECREF(code_ob);
+    Py_XDECREF(linetable_ob);
+    return result;
+}
+
+
+/******************
+ * source location tracking (co_lines/co_positions)
+ ******************/
+
+int
+PyCode_Addr2Line(PyCodeObject *co, int addrq)
+{
+    if (addrq < 0) {
+        return co->co_firstlineno;
+    }
+    assert(addrq >= 0 && addrq <= _PyCode_NBYTES(co));
+    PyCodeAddressRange bounds;
+    _PyCode_InitAddressRange(co, &bounds);
+    return _PyCode_CheckLineNumber(addrq, &bounds);
+}
+
+void
+_PyLineTable_InitAddressRange(const char *linetable, Py_ssize_t length, int firstlineno, PyCodeAddressRange *range)
+{
+    range->opaque.lo_next = (const uint8_t *)linetable;
+    range->opaque.limit = range->opaque.lo_next + length;
+    range->ar_start = -1;
+    range->ar_end = 0;
+    range->opaque.computed_line = firstlineno;
+    range->ar_line = -1;
+}
+
+int
+_PyCode_InitAddressRange(PyCodeObject* co, PyCodeAddressRange *bounds)
+{
+    assert(co->co_linetable != NULL);
+    const char *linetable = PyBytes_AS_STRING(co->co_linetable);
+    Py_ssize_t length = PyBytes_GET_SIZE(co->co_linetable);
+    _PyLineTable_InitAddressRange(linetable, length, co->co_firstlineno, bounds);
+    return bounds->ar_line;
+}
+
+/* Update *bounds to describe the first and one-past-the-last instructions in
+   the same line as lasti.  Return the number of that line, or -1 if lasti is out of bounds. */
+int
+_PyCode_CheckLineNumber(int lasti, PyCodeAddressRange *bounds)
+{
+    while (bounds->ar_end <= lasti) {
+        if (!_PyLineTable_NextAddressRange(bounds)) {
+            return -1;
+        }
+    }
+    while (bounds->ar_start > lasti) {
+        if (!_PyLineTable_PreviousAddressRange(bounds)) {
+            return -1;
+        }
+    }
+    return bounds->ar_line;
+}
+
+static int
+is_no_line_marker(uint8_t b)
+{
+    return (b >> 3) == 0x1f;
+}
+
+
+#define ASSERT_VALID_BOUNDS(bounds) \
+    assert(bounds->opaque.lo_next <=  bounds->opaque.limit && \
+        (bounds->ar_line == -1 || bounds->ar_line == bounds->opaque.computed_line) && \
+        (bounds->opaque.lo_next == bounds->opaque.limit || \
+        (*bounds->opaque.lo_next) & 128))
+
+static int
+next_code_delta(PyCodeAddressRange *bounds)
+{
+    assert((*bounds->opaque.lo_next) & 128);
+    return (((*bounds->opaque.lo_next) & 7) + 1) * sizeof(_Py_CODEUNIT);
+}
+
+static int
+previous_code_delta(PyCodeAddressRange *bounds)
+{
+    if (bounds->ar_start == 0) {
+        // If we looking at the first entry, the
+        // "previous" entry has an implicit length of 1.
+        return 1;
+    }
+    const uint8_t *ptr = bounds->opaque.lo_next-1;
+    while (((*ptr) & 128) == 0) {
+        ptr--;
+    }
+    return (((*ptr) & 7) + 1) * sizeof(_Py_CODEUNIT);
+}
+
+static int
+read_byte(PyCodeAddressRange *bounds)
+{
+    return *bounds->opaque.lo_next++;
+}
+
+static int
+read_varint(PyCodeAddressRange *bounds)
+{
+    unsigned int read = read_byte(bounds);
+    unsigned int val = read & 63;
+    unsigned int shift = 0;
+    while (read & 64) {
+        read = read_byte(bounds);
+        shift += 6;
+        val |= (read & 63) << shift;
+    }
+    return val;
+}
+
+static int
+read_signed_varint(PyCodeAddressRange *bounds)
+{
+    unsigned int uval = read_varint(bounds);
+    if (uval & 1) {
+        return -(int)(uval >> 1);
+    }
+    else {
+        return uval >> 1;
+    }
+}
+
+static void
+retreat(PyCodeAddressRange *bounds)
+{
+    ASSERT_VALID_BOUNDS(bounds);
+    assert(bounds->ar_start >= 0);
+    do {
+        bounds->opaque.lo_next--;
+    } while (((*bounds->opaque.lo_next) & 128) == 0);
+    bounds->opaque.computed_line -= get_line_delta(bounds->opaque.lo_next);
+    bounds->ar_end = bounds->ar_start;
+    bounds->ar_start -= previous_code_delta(bounds);
+    if (is_no_line_marker(bounds->opaque.lo_next[-1])) {
+        bounds->ar_line = -1;
+    }
+    else {
+        bounds->ar_line = bounds->opaque.computed_line;
+    }
+    ASSERT_VALID_BOUNDS(bounds);
+}
+
+static void
+advance(PyCodeAddressRange *bounds)
+{
+    ASSERT_VALID_BOUNDS(bounds);
+    bounds->opaque.computed_line += get_line_delta(bounds->opaque.lo_next);
+    if (is_no_line_marker(*bounds->opaque.lo_next)) {
+        bounds->ar_line = -1;
+    }
+    else {
+        bounds->ar_line = bounds->opaque.computed_line;
+    }
+    bounds->ar_start = bounds->ar_end;
+    bounds->ar_end += next_code_delta(bounds);
+    do {
+        bounds->opaque.lo_next++;
+    } while (bounds->opaque.lo_next < bounds->opaque.limit &&
+        ((*bounds->opaque.lo_next) & 128) == 0);
+    ASSERT_VALID_BOUNDS(bounds);
+}
+
+static void
+advance_with_locations(PyCodeAddressRange *bounds, int *endline, int *column, int *endcolumn)
+{
+    ASSERT_VALID_BOUNDS(bounds);
+    int first_byte = read_byte(bounds);
+    int code = (first_byte >> 3) & 15;
+    bounds->ar_start = bounds->ar_end;
+    bounds->ar_end = bounds->ar_start + ((first_byte & 7) + 1) * sizeof(_Py_CODEUNIT);
+    switch(code) {
+        case PY_CODE_LOCATION_INFO_NONE:
+            bounds->ar_line = *endline = -1;
+            *column =  *endcolumn = -1;
+            break;
+        case PY_CODE_LOCATION_INFO_LONG:
+        {
+            bounds->opaque.computed_line += read_signed_varint(bounds);
+            bounds->ar_line = bounds->opaque.computed_line;
+            *endline = bounds->ar_line + read_varint(bounds);
+            *column = read_varint(bounds)-1;
+            *endcolumn = read_varint(bounds)-1;
+            break;
+        }
+        case PY_CODE_LOCATION_INFO_NO_COLUMNS:
+        {
+            /* No column */
+            bounds->opaque.computed_line += read_signed_varint(bounds);
+            *endline = bounds->ar_line = bounds->opaque.computed_line;
+            *column = *endcolumn = -1;
+            break;
+        }
+        case PY_CODE_LOCATION_INFO_ONE_LINE0:
+        case PY_CODE_LOCATION_INFO_ONE_LINE1:
+        case PY_CODE_LOCATION_INFO_ONE_LINE2:
+        {
+            /* one line form */
+            int line_delta = code - 10;
+            bounds->opaque.computed_line += line_delta;
+            *endline = bounds->ar_line = bounds->opaque.computed_line;
+            *column = read_byte(bounds);
+            *endcolumn = read_byte(bounds);
+            break;
+        }
+        default:
+        {
+            /* Short forms */
+            int second_byte = read_byte(bounds);
+            assert((second_byte & 128) == 0);
+            *endline = bounds->ar_line = bounds->opaque.computed_line;
+            *column = code << 3 | (second_byte >> 4);
+            *endcolumn = *column + (second_byte & 15);
+        }
+    }
+    ASSERT_VALID_BOUNDS(bounds);
+}
+int
+PyCode_Addr2Location(PyCodeObject *co, int addrq,
+                     int *start_line, int *start_column,
+                     int *end_line, int *end_column)
+{
+    if (addrq < 0) {
+        *start_line = *end_line = co->co_firstlineno;
+        *start_column = *end_column = 0;
+        return 1;
+    }
+    assert(addrq >= 0 && addrq < _PyCode_NBYTES(co));
+    PyCodeAddressRange bounds;
+    _PyCode_InitAddressRange(co, &bounds);
+    _PyCode_CheckLineNumber(addrq, &bounds);
+    retreat(&bounds);
+    advance_with_locations(&bounds, end_line, start_column, end_column);
+    *start_line = bounds.ar_line;
+    return 1;
+}
+
+
+static inline int
+at_end(PyCodeAddressRange *bounds) {
+    return bounds->opaque.lo_next >= bounds->opaque.limit;
+}
+
+int
+_PyLineTable_PreviousAddressRange(PyCodeAddressRange *range)
+{
+    if (range->ar_start <= 0) {
+        return 0;
+    }
+    retreat(range);
+    assert(range->ar_end > range->ar_start);
+    return 1;
+}
+
+int
+_PyLineTable_NextAddressRange(PyCodeAddressRange *range)
+{
+    if (at_end(range)) {
+        return 0;
+    }
+    advance(range);
+    assert(range->ar_end > range->ar_start);
+    return 1;
+}
+
+static int
+emit_pair(PyObject **bytes, int *offset, int a, int b)
+{
+    Py_ssize_t len = PyBytes_GET_SIZE(*bytes);
+    if (*offset + 2 >= len) {
+        if (_PyBytes_Resize(bytes, len * 2) < 0)
+            return 0;
+    }
+    unsigned char *lnotab = (unsigned char *) PyBytes_AS_STRING(*bytes);
+    lnotab += *offset;
+    *lnotab++ = a;
+    *lnotab++ = b;
+    *offset += 2;
+    return 1;
+}
+
+static int
+emit_delta(PyObject **bytes, int bdelta, int ldelta, int *offset)
+{
+    while (bdelta > 255) {
+        if (!emit_pair(bytes, offset, 255, 0)) {
+            return 0;
+        }
+        bdelta -= 255;
+    }
+    while (ldelta > 127) {
+        if (!emit_pair(bytes, offset, bdelta, 127)) {
+            return 0;
+        }
+        bdelta = 0;
+        ldelta -= 127;
+    }
+    while (ldelta < -128) {
+        if (!emit_pair(bytes, offset, bdelta, -128)) {
+            return 0;
+        }
+        bdelta = 0;
+        ldelta += 128;
+    }
+    return emit_pair(bytes, offset, bdelta, ldelta);
+}
+
+static PyObject *
+decode_linetable(PyCodeObject *code)
+{
+    PyCodeAddressRange bounds;
+    PyObject *bytes;
+    int table_offset = 0;
+    int code_offset = 0;
+    int line = code->co_firstlineno;
+    bytes = PyBytes_FromStringAndSize(NULL, 64);
+    if (bytes == NULL) {
+        return NULL;
+    }
+    _PyCode_InitAddressRange(code, &bounds);
+    while (_PyLineTable_NextAddressRange(&bounds)) {
+        if (bounds.opaque.computed_line != line) {
+            int bdelta = bounds.ar_start - code_offset;
+            int ldelta = bounds.opaque.computed_line - line;
+            if (!emit_delta(&bytes, bdelta, ldelta, &table_offset)) {
+                Py_DECREF(bytes);
+                return NULL;
+            }
+            code_offset = bounds.ar_start;
+            line = bounds.opaque.computed_line;
+        }
+    }
+    _PyBytes_Resize(&bytes, table_offset);
+    return bytes;
+}
+
+
+typedef struct {
+    PyObject_HEAD
+    PyCodeObject *li_code;
+    PyCodeAddressRange li_line;
+} lineiterator;
+
+
+static void
+lineiter_dealloc(lineiterator *li)
+{
+    Py_DECREF(li->li_code);
+    Py_TYPE(li)->tp_free(li);
+}
+
+static PyObject *
+_source_offset_converter(int *value) {
+    if (*value == -1) {
+        Py_RETURN_NONE;
+    }
+    return PyLong_FromLong(*value);
+}
+
+static PyObject *
+lineiter_next(lineiterator *li)
+{
+    PyCodeAddressRange *bounds = &li->li_line;
+    if (!_PyLineTable_NextAddressRange(bounds)) {
+        return NULL;
+    }
+    int start = bounds->ar_start;
+    int line = bounds->ar_line;
+    // Merge overlapping entries:
+    while (_PyLineTable_NextAddressRange(bounds)) {
+        if (bounds->ar_line != line) {
+            _PyLineTable_PreviousAddressRange(bounds);
+            break;
+        }
+    }
+    return Py_BuildValue("iiO&", start, bounds->ar_end,
+                         _source_offset_converter, &line);
+}
+
+PyTypeObject _PyLineIterator = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "line_iterator",                    /* tp_name */
+    sizeof(lineiterator),               /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    /* methods */
+    (destructor)lineiter_dealloc,       /* tp_dealloc */
+    0,                                  /* tp_vectorcall_offset */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_as_async */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,       /* tp_flags */
+    0,                                  /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    PyObject_SelfIter,                  /* tp_iter */
+    (iternextfunc)lineiter_next,        /* tp_iternext */
+    0,                                  /* tp_methods */
+    0,                                  /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    0,                                  /* tp_init */
+    0,                                  /* tp_alloc */
+    0,                                  /* tp_new */
+    PyObject_Del,                       /* tp_free */
+};
+
+static lineiterator *
+new_linesiterator(PyCodeObject *code)
+{
+    lineiterator *li = (lineiterator *)PyType_GenericAlloc(&_PyLineIterator, 0);
+    if (li == NULL) {
+        return NULL;
+    }
+    li->li_code = (PyCodeObject*)Py_NewRef(code);
+    _PyCode_InitAddressRange(code, &li->li_line);
+    return li;
+}
+
+/* co_positions iterator object. */
+typedef struct {
+    PyObject_HEAD
+    PyCodeObject* pi_code;
+    PyCodeAddressRange pi_range;
+    int pi_offset;
+    int pi_endline;
+    int pi_column;
+    int pi_endcolumn;
+} positionsiterator;
+
+static void
+positionsiter_dealloc(positionsiterator* pi)
+{
+    Py_DECREF(pi->pi_code);
+    Py_TYPE(pi)->tp_free(pi);
+}
+
+static PyObject*
+positionsiter_next(positionsiterator* pi)
+{
+    if (pi->pi_offset >= pi->pi_range.ar_end) {
+        assert(pi->pi_offset == pi->pi_range.ar_end);
+        if (at_end(&pi->pi_range)) {
+            return NULL;
+        }
+        advance_with_locations(&pi->pi_range, &pi->pi_endline, &pi->pi_column, &pi->pi_endcolumn);
+    }
+    pi->pi_offset += 2;
+    return Py_BuildValue("(O&O&O&O&)",
+        _source_offset_converter, &pi->pi_range.ar_line,
+        _source_offset_converter, &pi->pi_endline,
+        _source_offset_converter, &pi->pi_column,
+        _source_offset_converter, &pi->pi_endcolumn);
+}
+
+PyTypeObject _PyPositionsIterator = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "positions_iterator",               /* tp_name */
+    sizeof(positionsiterator),          /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    /* methods */
+    (destructor)positionsiter_dealloc,  /* tp_dealloc */
+    0,                                  /* tp_vectorcall_offset */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_as_async */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,       /* tp_flags */
+    0,                                  /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    PyObject_SelfIter,                  /* tp_iter */
+    (iternextfunc)positionsiter_next,   /* tp_iternext */
+    0,                                  /* tp_methods */
+    0,                                  /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    0,                                  /* tp_init */
+    0,                                  /* tp_alloc */
+    0,                                  /* tp_new */
+    PyObject_Del,                       /* tp_free */
+};
+
+static PyObject*
+code_positionsiterator(PyCodeObject* code, PyObject* Py_UNUSED(args))
+{
+    positionsiterator* pi = (positionsiterator*)PyType_GenericAlloc(&_PyPositionsIterator, 0);
+    if (pi == NULL) {
+        return NULL;
+    }
+    pi->pi_code = (PyCodeObject*)Py_NewRef(code);
+    _PyCode_InitAddressRange(code, &pi->pi_range);
+    pi->pi_offset = pi->pi_range.ar_end;
+    return (PyObject*)pi;
+}
+
+
+/******************
+ * "extra" frame eval info (see PEP 523)
+ ******************/
+
+/* Holder for co_extra information */
+typedef struct {
+    Py_ssize_t ce_size;
+    void *ce_extras[1];
+} _PyCodeObjectExtra;
+
+
+int
+PyUnstable_Code_GetExtra(PyObject *code, Py_ssize_t index, void **extra)
+{
+    if (!PyCode_Check(code)) {
+        PyErr_BadInternalCall();
+        return -1;
+    }
+
+    PyCodeObject *o = (PyCodeObject*) code;
+    _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra*) o->co_extra;
+
+    if (co_extra == NULL || index < 0 || co_extra->ce_size <= index) {
+        *extra = NULL;
+        return 0;
+    }
+
+    *extra = co_extra->ce_extras[index];
+    return 0;
+}
+
+
+int
+PyUnstable_Code_SetExtra(PyObject *code, Py_ssize_t index, void *extra)
+{
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+
+    if (!PyCode_Check(code) || index < 0 ||
+            index >= interp->co_extra_user_count) {
+        PyErr_BadInternalCall();
+        return -1;
+    }
+
+    PyCodeObject *o = (PyCodeObject*) code;
+    _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra *) o->co_extra;
+
+    if (co_extra == NULL || co_extra->ce_size <= index) {
+        Py_ssize_t i = (co_extra == NULL ? 0 : co_extra->ce_size);
+        co_extra = PyMem_Realloc(
+                co_extra,
+                sizeof(_PyCodeObjectExtra) +
+                (interp->co_extra_user_count-1) * sizeof(void*));
+        if (co_extra == NULL) {
+            return -1;
+        }
+        for (; i < interp->co_extra_user_count; i++) {
+            co_extra->ce_extras[i] = NULL;
+        }
+        co_extra->ce_size = interp->co_extra_user_count;
+        o->co_extra = co_extra;
+    }
+
+    if (co_extra->ce_extras[index] != NULL) {
+        freefunc free = interp->co_extra_freefuncs[index];
+        if (free != NULL) {
+            free(co_extra->ce_extras[index]);
+        }
+    }
+
+    co_extra->ce_extras[index] = extra;
+    return 0;
+}
+
+
+/******************
+ * other PyCodeObject accessor functions
+ ******************/
+
+static PyObject *
+get_cached_locals(PyCodeObject *co, PyObject **cached_field,
+    _PyLocals_Kind kind, int num)
+{
+    assert(cached_field != NULL);
+    assert(co->_co_cached != NULL);
+    if (*cached_field != NULL) {
+        return Py_NewRef(*cached_field);
+    }
+    assert(*cached_field == NULL);
+    PyObject *varnames = get_localsplus_names(co, kind, num);
+    if (varnames == NULL) {
+        return NULL;
+    }
+    *cached_field = Py_NewRef(varnames);
+    return varnames;
+}
+
+PyObject *
+_PyCode_GetVarnames(PyCodeObject *co)
+{
+    if (init_co_cached(co)) {
+        return NULL;
+    }
+    return get_cached_locals(co, &co->_co_cached->_co_varnames, CO_FAST_LOCAL, co->co_nlocals);
+}
+
+PyObject *
+PyCode_GetVarnames(PyCodeObject *code)
+{
+    return _PyCode_GetVarnames(code);
+}
+
+PyObject *
+_PyCode_GetCellvars(PyCodeObject *co)
+{
+    if (init_co_cached(co)) {
+        return NULL;
+    }
+    return get_cached_locals(co, &co->_co_cached->_co_cellvars, CO_FAST_CELL, co->co_ncellvars);
+}
+
+PyObject *
+PyCode_GetCellvars(PyCodeObject *code)
+{
+    return _PyCode_GetCellvars(code);
+}
+
+PyObject *
+_PyCode_GetFreevars(PyCodeObject *co)
+{
+    if (init_co_cached(co)) {
+        return NULL;
+    }
+    return get_cached_locals(co, &co->_co_cached->_co_freevars, CO_FAST_FREE, co->co_nfreevars);
+}
+
+PyObject *
+PyCode_GetFreevars(PyCodeObject *code)
+{
+    return _PyCode_GetFreevars(code);
+}
+
+static void
+deopt_code(PyCodeObject *code, _Py_CODEUNIT *instructions)
+{
+    Py_ssize_t len = Py_SIZE(code);
+    for (int i = 0; i < len; i++) {
+        int opcode = _Py_GetBaseOpcode(code, i);
+        int caches = _PyOpcode_Caches[opcode];
+        instructions[i].op.code = opcode;
+        for (int j = 1; j <= caches; j++) {
+            instructions[i+j].cache = 0;
+        }
+        i += caches;
+    }
+}
+
+PyObject *
+_PyCode_GetCode(PyCodeObject *co)
+{
+    if (init_co_cached(co)) {
+        return NULL;
+    }
+    if (co->_co_cached->_co_code != NULL) {
+        return Py_NewRef(co->_co_cached->_co_code);
+    }
+    PyObject *code = PyBytes_FromStringAndSize((const char *)_PyCode_CODE(co),
+                                               _PyCode_NBYTES(co));
+    if (code == NULL) {
+        return NULL;
+    }
+    deopt_code(co, (_Py_CODEUNIT *)PyBytes_AS_STRING(code));
+    assert(co->_co_cached->_co_code == NULL);
+    co->_co_cached->_co_code = Py_NewRef(code);
+    return code;
+}
+
+PyObject *
+PyCode_GetCode(PyCodeObject *co)
+{
+    return _PyCode_GetCode(co);
+}
+
+/******************
+ * PyCode_Type
+ ******************/
+
+/*[clinic input]
+class code "PyCodeObject *" "&PyCode_Type"
+[clinic start generated code]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=78aa5d576683bb4b]*/
+
+/*[clinic input]
+@classmethod
+code.__new__ as code_new
+
+    argcount: int
+    posonlyargcount: int
+    kwonlyargcount: int
+    nlocals: int
+    stacksize: int
+    flags: int
+    codestring as code: object(subclass_of="&PyBytes_Type")
+    constants as consts: object(subclass_of="&PyTuple_Type")
+    names: object(subclass_of="&PyTuple_Type")
+    varnames: object(subclass_of="&PyTuple_Type")
+    filename: unicode
+    name: unicode
+    qualname: unicode
+    firstlineno: int
+    linetable: object(subclass_of="&PyBytes_Type")
+    exceptiontable: object(subclass_of="&PyBytes_Type")
+    freevars: object(subclass_of="&PyTuple_Type", c_default="NULL") = ()
+    cellvars: object(subclass_of="&PyTuple_Type", c_default="NULL") = ()
+    /
+
+Create a code object.  Not for the faint of heart.
+[clinic start generated code]*/
+
+static PyObject *
+code_new_impl(PyTypeObject *type, int argcount, int posonlyargcount,
+              int kwonlyargcount, int nlocals, int stacksize, int flags,
+              PyObject *code, PyObject *consts, PyObject *names,
+              PyObject *varnames, PyObject *filename, PyObject *name,
+              PyObject *qualname, int firstlineno, PyObject *linetable,
+              PyObject *exceptiontable, PyObject *freevars,
+              PyObject *cellvars)
+/*[clinic end generated code: output=069fa20d299f9dda input=e31da3c41ad8064a]*/
+{
+    PyObject *co = NULL;
+    PyObject *ournames = NULL;
+    PyObject *ourvarnames = NULL;
+    PyObject *ourfreevars = NULL;
+    PyObject *ourcellvars = NULL;
+
+    if (PySys_Audit("code.__new__", "OOOiiiiii",
+                    code, filename, name, argcount, posonlyargcount,
+                    kwonlyargcount, nlocals, stacksize, flags) < 0) {
+        goto cleanup;
+    }
+
+    if (argcount < 0) {
+        PyErr_SetString(
+            PyExc_ValueError,
+            "code: argcount must not be negative");
+        goto cleanup;
+    }
+
+    if (posonlyargcount < 0) {
+        PyErr_SetString(
+            PyExc_ValueError,
+            "code: posonlyargcount must not be negative");
+        goto cleanup;
+    }
+
+    if (kwonlyargcount < 0) {
+        PyErr_SetString(
+            PyExc_ValueError,
+            "code: kwonlyargcount must not be negative");
+        goto cleanup;
+    }
+    if (nlocals < 0) {
+        PyErr_SetString(
+            PyExc_ValueError,
+            "code: nlocals must not be negative");
+        goto cleanup;
+    }
+
+    ournames = validate_and_copy_tuple(names);
+    if (ournames == NULL)
+        goto cleanup;
+    ourvarnames = validate_and_copy_tuple(varnames);
+    if (ourvarnames == NULL)
+        goto cleanup;
+    if (freevars)
+        ourfreevars = validate_and_copy_tuple(freevars);
+    else
+        ourfreevars = PyTuple_New(0);
+    if (ourfreevars == NULL)
+        goto cleanup;
+    if (cellvars)
+        ourcellvars = validate_and_copy_tuple(cellvars);
+    else
+        ourcellvars = PyTuple_New(0);
+    if (ourcellvars == NULL)
+        goto cleanup;
+
+    co = (PyObject *)PyCode_NewWithPosOnlyArgs(argcount, posonlyargcount,
+                                               kwonlyargcount,
+                                               nlocals, stacksize, flags,
+                                               code, consts, ournames,
+                                               ourvarnames, ourfreevars,
+                                               ourcellvars, filename,
+                                               name, qualname, firstlineno,
+                                               linetable,
+                                               exceptiontable
+                                              );
+  cleanup:
+    Py_XDECREF(ournames);
+    Py_XDECREF(ourvarnames);
+    Py_XDECREF(ourfreevars);
+    Py_XDECREF(ourcellvars);
+    return co;
+}
+
+static void
+free_monitoring_data(_PyCoMonitoringData *data)
+{
+    if (data == NULL) {
+        return;
+    }
+    if (data->tools) {
+        PyMem_Free(data->tools);
+    }
+    if (data->lines) {
+        PyMem_Free(data->lines);
+    }
+    if (data->line_tools) {
+        PyMem_Free(data->line_tools);
+    }
+    if (data->per_instruction_opcodes) {
+        PyMem_Free(data->per_instruction_opcodes);
+    }
+    if (data->per_instruction_tools) {
+        PyMem_Free(data->per_instruction_tools);
+    }
+    PyMem_Free(data);
+}
+
+static void
+code_dealloc(PyCodeObject *co)
+{
+    assert(Py_REFCNT(co) == 0);
+    Py_SET_REFCNT(co, 1);
+    notify_code_watchers(PY_CODE_EVENT_DESTROY, co);
+    if (Py_REFCNT(co) > 1) {
+        Py_SET_REFCNT(co, Py_REFCNT(co) - 1);
+        return;
+    }
+    Py_SET_REFCNT(co, 0);
+
+    if (co->co_extra != NULL) {
+        PyInterpreterState *interp = _PyInterpreterState_GET();
+        _PyCodeObjectExtra *co_extra = co->co_extra;
+
+        for (Py_ssize_t i = 0; i < co_extra->ce_size; i++) {
+            freefunc free_extra = interp->co_extra_freefuncs[i];
+
+            if (free_extra != NULL) {
+                free_extra(co_extra->ce_extras[i]);
+            }
+        }
+
+        PyMem_Free(co_extra);
+    }
+
+    Py_XDECREF(co->co_consts);
+    Py_XDECREF(co->co_names);
+    Py_XDECREF(co->co_localsplusnames);
+    Py_XDECREF(co->co_localspluskinds);
+    Py_XDECREF(co->co_filename);
+    Py_XDECREF(co->co_name);
+    Py_XDECREF(co->co_qualname);
+    Py_XDECREF(co->co_linetable);
+    Py_XDECREF(co->co_exceptiontable);
+    if (co->_co_cached != NULL) {
+        Py_XDECREF(co->_co_cached->_co_code);
+        Py_XDECREF(co->_co_cached->_co_cellvars);
+        Py_XDECREF(co->_co_cached->_co_freevars);
+        Py_XDECREF(co->_co_cached->_co_varnames);
+        PyMem_Free(co->_co_cached);
+    }
+    if (co->co_weakreflist != NULL) {
+        PyObject_ClearWeakRefs((PyObject*)co);
+    }
+    free_monitoring_data(co->_co_monitoring);
+    PyObject_Free(co);
+}
+
+static PyObject *
+code_repr(PyCodeObject *co)
+{
+    int lineno;
+    if (co->co_firstlineno != 0)
+        lineno = co->co_firstlineno;
+    else
+        lineno = -1;
+    if (co->co_filename && PyUnicode_Check(co->co_filename)) {
+        return PyUnicode_FromFormat(
+            "<code object %U at %p, file \"%U\", line %d>",
+            co->co_name, co, co->co_filename, lineno);
+    } else {
+        return PyUnicode_FromFormat(
+            "<code object %U at %p, file ???, line %d>",
+            co->co_name, co, lineno);
+    }
+}
+
+static PyObject *
+code_richcompare(PyObject *self, PyObject *other, int op)
+{
+    PyCodeObject *co, *cp;
+    int eq;
+    PyObject *consts1, *consts2;
+    PyObject *res;
+
+    if ((op != Py_EQ && op != Py_NE) ||
+        !PyCode_Check(self) ||
+        !PyCode_Check(other)) {
+        Py_RETURN_NOTIMPLEMENTED;
+    }
+
+    co = (PyCodeObject *)self;
+    cp = (PyCodeObject *)other;
+
+    eq = PyObject_RichCompareBool(co->co_name, cp->co_name, Py_EQ);
+    if (!eq) goto unequal;
+    eq = co->co_argcount == cp->co_argcount;
+    if (!eq) goto unequal;
+    eq = co->co_posonlyargcount == cp->co_posonlyargcount;
+    if (!eq) goto unequal;
+    eq = co->co_kwonlyargcount == cp->co_kwonlyargcount;
+    if (!eq) goto unequal;
+    eq = co->co_flags == cp->co_flags;
+    if (!eq) goto unequal;
+    eq = co->co_firstlineno == cp->co_firstlineno;
+    if (!eq) goto unequal;
+    eq = Py_SIZE(co) == Py_SIZE(cp);
+    if (!eq) {
+        goto unequal;
+    }
+    for (int i = 0; i < Py_SIZE(co); i++) {
+        _Py_CODEUNIT co_instr = _PyCode_CODE(co)[i];
+        _Py_CODEUNIT cp_instr = _PyCode_CODE(cp)[i];
+        co_instr.op.code = _Py_GetBaseOpcode(co, i);
+        cp_instr.op.code = _Py_GetBaseOpcode(cp, i);
+        eq = co_instr.cache == cp_instr.cache;
+        if (!eq) {
+            goto unequal;
+        }
+        i += _PyOpcode_Caches[co_instr.op.code];
+    }
+
+    /* compare constants */
+    consts1 = _PyCode_ConstantKey(co->co_consts);
+    if (!consts1)
+        return NULL;
+    consts2 = _PyCode_ConstantKey(cp->co_consts);
+    if (!consts2) {
+        Py_DECREF(consts1);
+        return NULL;
+    }
+    eq = PyObject_RichCompareBool(consts1, consts2, Py_EQ);
+    Py_DECREF(consts1);
+    Py_DECREF(consts2);
+    if (eq <= 0) goto unequal;
+
+    eq = PyObject_RichCompareBool(co->co_names, cp->co_names, Py_EQ);
+    if (eq <= 0) goto unequal;
+    eq = PyObject_RichCompareBool(co->co_localsplusnames,
+                                  cp->co_localsplusnames, Py_EQ);
+    if (eq <= 0) goto unequal;
+    eq = PyObject_RichCompareBool(co->co_linetable, cp->co_linetable, Py_EQ);
+    if (eq <= 0) {
+        goto unequal;
+    }
+    eq = PyObject_RichCompareBool(co->co_exceptiontable,
+                                  cp->co_exceptiontable, Py_EQ);
+    if (eq <= 0) {
+        goto unequal;
+    }
+
+    if (op == Py_EQ)
+        res = Py_True;
+    else
+        res = Py_False;
+    goto done;
+
+  unequal:
+    if (eq < 0)
+        return NULL;
+    if (op == Py_NE)
+        res = Py_True;
+    else
+        res = Py_False;
+
+  done:
+    return Py_NewRef(res);
+}
+
+static Py_hash_t
+code_hash(PyCodeObject *co)
+{
+    Py_uhash_t uhash = 20221211;
+    #define SCRAMBLE_IN(H) do {       \
+        uhash ^= (Py_uhash_t)(H);     \
+        uhash *= _PyHASH_MULTIPLIER;  \
+    } while (0)
+    #define SCRAMBLE_IN_HASH(EXPR) do {     \
+        Py_hash_t h = PyObject_Hash(EXPR);  \
+        if (h == -1) {                      \
+            return -1;                      \
+        }                                   \
+        SCRAMBLE_IN(h);                     \
+    } while (0)
+
+    SCRAMBLE_IN_HASH(co->co_name);
+    SCRAMBLE_IN_HASH(co->co_consts);
+    SCRAMBLE_IN_HASH(co->co_names);
+    SCRAMBLE_IN_HASH(co->co_localsplusnames);
+    SCRAMBLE_IN_HASH(co->co_linetable);
+    SCRAMBLE_IN_HASH(co->co_exceptiontable);
+    SCRAMBLE_IN(co->co_argcount);
+    SCRAMBLE_IN(co->co_posonlyargcount);
+    SCRAMBLE_IN(co->co_kwonlyargcount);
+    SCRAMBLE_IN(co->co_flags);
+    SCRAMBLE_IN(co->co_firstlineno);
+    SCRAMBLE_IN(Py_SIZE(co));
+    for (int i = 0; i < Py_SIZE(co); i++) {
+        int deop = _Py_GetBaseOpcode(co, i);
+        SCRAMBLE_IN(deop);
+        SCRAMBLE_IN(_PyCode_CODE(co)[i].op.arg);
+        i += _PyOpcode_Caches[deop];
+    }
+    if ((Py_hash_t)uhash == -1) {
+        return -2;
+    }
+    return (Py_hash_t)uhash;
+}
+
+
+#define OFF(x) offsetof(PyCodeObject, x)
+
+static PyMemberDef code_memberlist[] = {
+    {"co_argcount",        T_INT,    OFF(co_argcount),        READONLY},
+    {"co_posonlyargcount", T_INT,    OFF(co_posonlyargcount), READONLY},
+    {"co_kwonlyargcount",  T_INT,    OFF(co_kwonlyargcount),  READONLY},
+    {"co_stacksize",       T_INT,    OFF(co_stacksize),       READONLY},
+    {"co_flags",           T_INT,    OFF(co_flags),           READONLY},
+    {"co_nlocals",         T_INT,    OFF(co_nlocals),         READONLY},
+    {"co_consts",          T_OBJECT, OFF(co_consts),          READONLY},
+    {"co_names",           T_OBJECT, OFF(co_names),           READONLY},
+    {"co_filename",        T_OBJECT, OFF(co_filename),        READONLY},
+    {"co_name",            T_OBJECT, OFF(co_name),            READONLY},
+    {"co_qualname",        T_OBJECT, OFF(co_qualname),        READONLY},
+    {"co_firstlineno",     T_INT,    OFF(co_firstlineno),     READONLY},
+    {"co_linetable",       T_OBJECT, OFF(co_linetable),       READONLY},
+    {"co_exceptiontable",  T_OBJECT, OFF(co_exceptiontable),  READONLY},
+    {NULL}      /* Sentinel */
+};
+
+
+static PyObject *
+code_getlnotab(PyCodeObject *code, void *closure)
+{
+    if (PyErr_WarnEx(PyExc_DeprecationWarning,
+                     "co_lnotab is deprecated, use co_lines instead.",
+                     1) < 0) {
+        return NULL;
+    }
+    return decode_linetable(code);
+}
+
+static PyObject *
+code_getvarnames(PyCodeObject *code, void *closure)
+{
+    return _PyCode_GetVarnames(code);
+}
+
+static PyObject *
+code_getcellvars(PyCodeObject *code, void *closure)
+{
+    return _PyCode_GetCellvars(code);
+}
+
+static PyObject *
+code_getfreevars(PyCodeObject *code, void *closure)
+{
+    return _PyCode_GetFreevars(code);
+}
+
+static PyObject *
+code_getcodeadaptive(PyCodeObject *code, void *closure)
+{
+    return PyBytes_FromStringAndSize(code->co_code_adaptive,
+                                     _PyCode_NBYTES(code));
+}
+
+static PyObject *
+code_getcode(PyCodeObject *code, void *closure)
+{
+    return _PyCode_GetCode(code);
+}
+
+static PyGetSetDef code_getsetlist[] = {
+    {"co_lnotab",         (getter)code_getlnotab,       NULL, NULL},
+    {"_co_code_adaptive", (getter)code_getcodeadaptive, NULL, NULL},
+    // The following old names are kept for backward compatibility.
+    {"co_varnames",       (getter)code_getvarnames,     NULL, NULL},
+    {"co_cellvars",       (getter)code_getcellvars,     NULL, NULL},
+    {"co_freevars",       (getter)code_getfreevars,     NULL, NULL},
+    {"co_code",           (getter)code_getcode,         NULL, NULL},
+    {0}
+};
+
+
+static PyObject *
+code_sizeof(PyCodeObject *co, PyObject *Py_UNUSED(args))
+{
+    size_t res = _PyObject_VAR_SIZE(Py_TYPE(co), Py_SIZE(co));
+    _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra*) co->co_extra;
+    if (co_extra != NULL) {
+        res += sizeof(_PyCodeObjectExtra);
+        res += ((size_t)co_extra->ce_size - 1) * sizeof(co_extra->ce_extras[0]);
+    }
+    return PyLong_FromSize_t(res);
+}
+
+static PyObject *
+code_linesiterator(PyCodeObject *code, PyObject *Py_UNUSED(args))
+{
+    return (PyObject *)new_linesiterator(code);
+}
+
+/*[clinic input]
+@text_signature "($self, /, **changes)"
+code.replace
+
+    *
+    co_argcount: int(c_default="self->co_argcount") = unchanged
+    co_posonlyargcount: int(c_default="self->co_posonlyargcount") = unchanged
+    co_kwonlyargcount: int(c_default="self->co_kwonlyargcount") = unchanged
+    co_nlocals: int(c_default="self->co_nlocals") = unchanged
+    co_stacksize: int(c_default="self->co_stacksize") = unchanged
+    co_flags: int(c_default="self->co_flags") = unchanged
+    co_firstlineno: int(c_default="self->co_firstlineno") = unchanged
+    co_code: object(subclass_of="&PyBytes_Type", c_default="NULL") = unchanged
+    co_consts: object(subclass_of="&PyTuple_Type", c_default="self->co_consts") = unchanged
+    co_names: object(subclass_of="&PyTuple_Type", c_default="self->co_names") = unchanged
+    co_varnames: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
+    co_freevars: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
+    co_cellvars: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
+    co_filename: unicode(c_default="self->co_filename") = unchanged
+    co_name: unicode(c_default="self->co_name") = unchanged
+    co_qualname: unicode(c_default="self->co_qualname") = unchanged
+    co_linetable: object(subclass_of="&PyBytes_Type", c_default="self->co_linetable") = unchanged
+    co_exceptiontable: object(subclass_of="&PyBytes_Type", c_default="self->co_exceptiontable") = unchanged
+
+Return a copy of the code object with new values for the specified fields.
+[clinic start generated code]*/
+
+static PyObject *
+code_replace_impl(PyCodeObject *self, int co_argcount,
+                  int co_posonlyargcount, int co_kwonlyargcount,
+                  int co_nlocals, int co_stacksize, int co_flags,
+                  int co_firstlineno, PyObject *co_code, PyObject *co_consts,
+                  PyObject *co_names, PyObject *co_varnames,
+                  PyObject *co_freevars, PyObject *co_cellvars,
+                  PyObject *co_filename, PyObject *co_name,
+                  PyObject *co_qualname, PyObject *co_linetable,
+                  PyObject *co_exceptiontable)
+/*[clinic end generated code: output=e75c48a15def18b9 input=18e280e07846c122]*/
+{
+#define CHECK_INT_ARG(ARG) \
+        if (ARG < 0) { \
+            PyErr_SetString(PyExc_ValueError, \
+                            #ARG " must be a positive integer"); \
+            return NULL; \
+        }
+
+    CHECK_INT_ARG(co_argcount);
+    CHECK_INT_ARG(co_posonlyargcount);
+    CHECK_INT_ARG(co_kwonlyargcount);
+    CHECK_INT_ARG(co_nlocals);
+    CHECK_INT_ARG(co_stacksize);
+    CHECK_INT_ARG(co_flags);
+    CHECK_INT_ARG(co_firstlineno);
+
+#undef CHECK_INT_ARG
+
+    PyObject *code = NULL;
+    if (co_code == NULL) {
+        code = _PyCode_GetCode(self);
+        if (code == NULL) {
+            return NULL;
+        }
+        co_code = code;
+    }
+
+    if (PySys_Audit("code.__new__", "OOOiiiiii",
+                    co_code, co_filename, co_name, co_argcount,
+                    co_posonlyargcount, co_kwonlyargcount, co_nlocals,
+                    co_stacksize, co_flags) < 0) {
+        Py_XDECREF(code);
+        return NULL;
+    }
+
+    PyCodeObject *co = NULL;
+    PyObject *varnames = NULL;
+    PyObject *cellvars = NULL;
+    PyObject *freevars = NULL;
+    if (co_varnames == NULL) {
+        varnames = get_localsplus_names(self, CO_FAST_LOCAL, self->co_nlocals);
+        if (varnames == NULL) {
+            goto error;
+        }
+        co_varnames = varnames;
+    }
+    if (co_cellvars == NULL) {
+        cellvars = get_localsplus_names(self, CO_FAST_CELL, self->co_ncellvars);
+        if (cellvars == NULL) {
+            goto error;
+        }
+        co_cellvars = cellvars;
+    }
+    if (co_freevars == NULL) {
+        freevars = get_localsplus_names(self, CO_FAST_FREE, self->co_nfreevars);
+        if (freevars == NULL) {
+            goto error;
+        }
+        co_freevars = freevars;
+    }
+
+    co = PyCode_NewWithPosOnlyArgs(
+        co_argcount, co_posonlyargcount, co_kwonlyargcount, co_nlocals,
+        co_stacksize, co_flags, co_code, co_consts, co_names,
+        co_varnames, co_freevars, co_cellvars, co_filename, co_name,
+        co_qualname, co_firstlineno,
+        co_linetable, co_exceptiontable);
+
+error:
+    Py_XDECREF(code);
+    Py_XDECREF(varnames);
+    Py_XDECREF(cellvars);
+    Py_XDECREF(freevars);
+    return (PyObject *)co;
+}
+
+/*[clinic input]
+code._varname_from_oparg
+
+    oparg: int
+
+(internal-only) Return the local variable name for the given oparg.
+
+WARNING: this method is for internal use only and may change or go away.
+[clinic start generated code]*/
+
+static PyObject *
+code__varname_from_oparg_impl(PyCodeObject *self, int oparg)
+/*[clinic end generated code: output=1fd1130413184206 input=c5fa3ee9bac7d4ca]*/
+{
+    PyObject *name = PyTuple_GetItem(self->co_localsplusnames, oparg);
+    if (name == NULL) {
+        return NULL;
+    }
+    return Py_NewRef(name);
+}
+
+/* XXX code objects need to participate in GC? */
+
+static struct PyMethodDef code_methods[] = {
+    {"__sizeof__", (PyCFunction)code_sizeof, METH_NOARGS},
+    {"co_lines", (PyCFunction)code_linesiterator, METH_NOARGS},
+    {"co_positions", (PyCFunction)code_positionsiterator, METH_NOARGS},
+    CODE_REPLACE_METHODDEF
+    CODE__VARNAME_FROM_OPARG_METHODDEF
+    {NULL, NULL}                /* sentinel */
+};
+
+
+PyTypeObject PyCode_Type = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "code",
+    offsetof(PyCodeObject, co_code_adaptive),
+    sizeof(_Py_CODEUNIT),
+    (destructor)code_dealloc,           /* tp_dealloc */
+    0,                                  /* tp_vectorcall_offset */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_as_async */
+    (reprfunc)code_repr,                /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    (hashfunc)code_hash,                /* tp_hash */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    PyObject_GenericGetAttr,            /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    code_new__doc__,                    /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    code_richcompare,                   /* tp_richcompare */
+    offsetof(PyCodeObject, co_weakreflist),     /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    code_methods,                       /* tp_methods */
+    code_memberlist,                    /* tp_members */
+    code_getsetlist,                    /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    0,                                  /* tp_init */
+    0,                                  /* tp_alloc */
+    code_new,                           /* tp_new */
+};
+
+
+/******************
+ * other API
+ ******************/
+
+PyObject*
+_PyCode_ConstantKey(PyObject *op)
+{
+    PyObject *key;
+
+    /* Py_None and Py_Ellipsis are singletons. */
+    if (op == Py_None || op == Py_Ellipsis
+       || PyLong_CheckExact(op)
+       || PyUnicode_CheckExact(op)
+          /* code_richcompare() uses _PyCode_ConstantKey() internally */
+       || PyCode_Check(op))
+    {
+        /* Objects of these types are always different from object of other
+         * type and from tuples. */
+        key = Py_NewRef(op);
+    }
+    else if (PyBool_Check(op) || PyBytes_CheckExact(op)) {
+        /* Make booleans different from integers 0 and 1.
+         * Avoid BytesWarning from comparing bytes with strings. */
+        key = PyTuple_Pack(2, Py_TYPE(op), op);
+    }
+    else if (PyFloat_CheckExact(op)) {
+        double d = PyFloat_AS_DOUBLE(op);
+        /* all we need is to make the tuple different in either the 0.0
+         * or -0.0 case from all others, just to avoid the "coercion".
+         */
+        if (d == 0.0 && copysign(1.0, d) < 0.0)
+            key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
+        else
+            key = PyTuple_Pack(2, Py_TYPE(op), op);
+    }
+    else if (PyComplex_CheckExact(op)) {
+        Py_complex z;
+        int real_negzero, imag_negzero;
+        /* For the complex case we must make complex(x, 0.)
+           different from complex(x, -0.) and complex(0., y)
+           different from complex(-0., y), for any x and y.
+           All four complex zeros must be distinguished.*/
+        z = PyComplex_AsCComplex(op);
+        real_negzero = z.real == 0.0 && copysign(1.0, z.real) < 0.0;
+        imag_negzero = z.imag == 0.0 && copysign(1.0, z.imag) < 0.0;
+        /* use True, False and None singleton as tags for the real and imag
+         * sign, to make tuples different */
+        if (real_negzero && imag_negzero) {
+            key = PyTuple_Pack(3, Py_TYPE(op), op, Py_True);
+        }
+        else if (imag_negzero) {
+            key = PyTuple_Pack(3, Py_TYPE(op), op, Py_False);
+        }
+        else if (real_negzero) {
+            key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
+        }
+        else {
+            key = PyTuple_Pack(2, Py_TYPE(op), op);
+        }
+    }
+    else if (PyTuple_CheckExact(op)) {
+        Py_ssize_t i, len;
+        PyObject *tuple;
+
+        len = PyTuple_GET_SIZE(op);
+        tuple = PyTuple_New(len);
+        if (tuple == NULL)
+            return NULL;
+
+        for (i=0; i < len; i++) {
+            PyObject *item, *item_key;
+
+            item = PyTuple_GET_ITEM(op, i);
+            item_key = _PyCode_ConstantKey(item);
+            if (item_key == NULL) {
+                Py_DECREF(tuple);
+                return NULL;
+            }
+
+            PyTuple_SET_ITEM(tuple, i, item_key);
+        }
+
+        key = PyTuple_Pack(2, tuple, op);
+        Py_DECREF(tuple);
+    }
+    else if (PyFrozenSet_CheckExact(op)) {
+        Py_ssize_t pos = 0;
+        PyObject *item;
+        Py_hash_t hash;
+        Py_ssize_t i, len;
+        PyObject *tuple, *set;
+
+        len = PySet_GET_SIZE(op);
+        tuple = PyTuple_New(len);
+        if (tuple == NULL)
+            return NULL;
+
+        i = 0;
+        while (_PySet_NextEntry(op, &pos, &item, &hash)) {
+            PyObject *item_key;
+
+            item_key = _PyCode_ConstantKey(item);
+            if (item_key == NULL) {
+                Py_DECREF(tuple);
+                return NULL;
+            }
+
+            assert(i < len);
+            PyTuple_SET_ITEM(tuple, i, item_key);
+            i++;
+        }
+        set = PyFrozenSet_New(tuple);
+        Py_DECREF(tuple);
+        if (set == NULL)
+            return NULL;
+
+        key = PyTuple_Pack(2, set, op);
+        Py_DECREF(set);
+        return key;
+    }
+    else {
+        /* for other types, use the object identifier as a unique identifier
+         * to ensure that they are seen as unequal. */
+        PyObject *obj_id = PyLong_FromVoidPtr(op);
+        if (obj_id == NULL)
+            return NULL;
+
+        key = PyTuple_Pack(2, obj_id, op);
+        Py_DECREF(obj_id);
+    }
+    return key;
+}
+
+void
+_PyStaticCode_Fini(PyCodeObject *co)
+{
+    deopt_code(co, _PyCode_CODE(co));
+    PyMem_Free(co->co_extra);
+    if (co->_co_cached != NULL) {
+        Py_CLEAR(co->_co_cached->_co_code);
+        Py_CLEAR(co->_co_cached->_co_cellvars);
+        Py_CLEAR(co->_co_cached->_co_freevars);
+        Py_CLEAR(co->_co_cached->_co_varnames);
+        PyMem_Free(co->_co_cached);
+        co->_co_cached = NULL;
+    }
+    co->co_extra = NULL;
+    if (co->co_weakreflist != NULL) {
+        PyObject_ClearWeakRefs((PyObject *)co);
+        co->co_weakreflist = NULL;
+    }
+    free_monitoring_data(co->_co_monitoring);
+    co->_co_monitoring = NULL;
+}
+
+int
+_PyStaticCode_Init(PyCodeObject *co)
+{
+    int res = intern_strings(co->co_names);
+    if (res < 0) {
+        return -1;
+    }
+    res = intern_string_constants(co->co_consts, NULL);
+    if (res < 0) {
+        return -1;
+    }
+    res = intern_strings(co->co_localsplusnames);
+    if (res < 0) {
+        return -1;
+    }
+    _PyCode_Quicken(co);
+    return 0;
+}
+
+#define MAX_CODE_UNITS_PER_LOC_ENTRY 8
+
+PyCodeObject *
+_Py_MakeShimCode(const _PyShimCodeDef *codedef)
+{
+    PyObject *name = NULL;
+    PyObject *co_code = NULL;
+    PyObject *lines = NULL;
+    PyCodeObject *codeobj = NULL;
+    uint8_t *loc_table = NULL;
+
+    name = _PyUnicode_FromASCII(codedef->cname, strlen(codedef->cname));
+    if (name == NULL) {
+        goto cleanup;
+    }
+    co_code = PyBytes_FromStringAndSize(
+        (const char *)codedef->code, codedef->codelen);
+    if (co_code == NULL) {
+        goto cleanup;
+    }
+    int code_units = codedef->codelen / sizeof(_Py_CODEUNIT);
+    int loc_entries = (code_units + MAX_CODE_UNITS_PER_LOC_ENTRY - 1) /
+                      MAX_CODE_UNITS_PER_LOC_ENTRY;
+    loc_table = PyMem_Malloc(loc_entries);
+    if (loc_table == NULL) {
+        PyErr_NoMemory();
+        goto cleanup;
+    }
+    for (int i = 0; i < loc_entries-1; i++) {
+         loc_table[i] = 0x80 | (PY_CODE_LOCATION_INFO_NONE << 3) | 7;
+         code_units -= MAX_CODE_UNITS_PER_LOC_ENTRY;
+    }
+    assert(loc_entries > 0);
+    assert(code_units > 0 && code_units <= MAX_CODE_UNITS_PER_LOC_ENTRY);
+    loc_table[loc_entries-1] = 0x80 |
+        (PY_CODE_LOCATION_INFO_NONE << 3) | (code_units-1);
+    lines = PyBytes_FromStringAndSize((const char *)loc_table, loc_entries);
+    PyMem_Free(loc_table);
+    if (lines == NULL) {
+        goto cleanup;
+    }
+    _Py_DECLARE_STR(shim_name, "<shim>");
+    struct _PyCodeConstructor con = {
+        .filename = &_Py_STR(shim_name),
+        .name = name,
+        .qualname = name,
+        .flags = CO_NEWLOCALS | CO_OPTIMIZED,
+
+        .code = co_code,
+        .firstlineno = 1,
+        .linetable = lines,
+
+        .consts = (PyObject *)&_Py_SINGLETON(tuple_empty),
+        .names = (PyObject *)&_Py_SINGLETON(tuple_empty),
+
+        .localsplusnames = (PyObject *)&_Py_SINGLETON(tuple_empty),
+        .localspluskinds = (PyObject *)&_Py_SINGLETON(bytes_empty),
+
+        .argcount = 0,
+        .posonlyargcount = 0,
+        .kwonlyargcount = 0,
+
+        .stacksize = codedef->stacksize,
+
+        .exceptiontable = (PyObject *)&_Py_SINGLETON(bytes_empty),
+    };
+
+    codeobj = _PyCode_New(&con);
+cleanup:
+    Py_XDECREF(name);
+    Py_XDECREF(co_code);
+    Py_XDECREF(lines);
+    return codeobj;
+}