(root)/
Python-3.12.0/
Objects/
codeobject.c
       1  #include <stdbool.h>
       2  
       3  #include "Python.h"
       4  #include "opcode.h"
       5  #include "structmember.h"         // PyMemberDef
       6  #include "pycore_code.h"          // _PyCodeConstructor
       7  #include "pycore_frame.h"         // FRAME_SPECIALS_SIZE
       8  #include "pycore_interp.h"        // PyInterpreterState.co_extra_freefuncs
       9  #include "pycore_opcode.h"        // _PyOpcode_Deopt
      10  #include "pycore_pystate.h"       // _PyInterpreterState_GET()
      11  #include "pycore_tuple.h"         // _PyTuple_ITEMS()
      12  #include "clinic/codeobject.c.h"
      13  
      14  static PyObject* code_repr(PyCodeObject *co);
      15  
      16  static const char *
      17  code_event_name(PyCodeEvent event) {
      18      switch (event) {
      19          #define CASE(op)                \
      20          case PY_CODE_EVENT_##op:         \
      21              return "PY_CODE_EVENT_" #op;
      22          PY_FOREACH_CODE_EVENT(CASE)
      23          #undef CASE
      24      }
      25      Py_UNREACHABLE();
      26  }
      27  
      28  static void
      29  notify_code_watchers(PyCodeEvent event, PyCodeObject *co)
      30  {
      31      assert(Py_REFCNT(co) > 0);
      32      PyInterpreterState *interp = _PyInterpreterState_GET();
      33      assert(interp->_initialized);
      34      uint8_t bits = interp->active_code_watchers;
      35      int i = 0;
      36      while (bits) {
      37          assert(i < CODE_MAX_WATCHERS);
      38          if (bits & 1) {
      39              PyCode_WatchCallback cb = interp->code_watchers[i];
      40              // callback must be non-null if the watcher bit is set
      41              assert(cb != NULL);
      42              if (cb(event, co) < 0) {
      43                  // Don't risk resurrecting the object if an unraisablehook keeps
      44                  // a reference; pass a string as context.
      45                  PyObject *context = NULL;
      46                  PyObject *repr = code_repr(co);
      47                  if (repr) {
      48                      context = PyUnicode_FromFormat(
      49                          "%s watcher callback for %U",
      50                          code_event_name(event), repr);
      51                      Py_DECREF(repr);
      52                  }
      53                  if (context == NULL) {
      54                      context = Py_NewRef(Py_None);
      55                  }
      56                  PyErr_WriteUnraisable(context);
      57                  Py_DECREF(context);
      58              }
      59          }
      60          i++;
      61          bits >>= 1;
      62      }
      63  }
      64  
      65  int
      66  PyCode_AddWatcher(PyCode_WatchCallback callback)
      67  {
      68      PyInterpreterState *interp = _PyInterpreterState_GET();
      69      assert(interp->_initialized);
      70  
      71      for (int i = 0; i < CODE_MAX_WATCHERS; i++) {
      72          if (!interp->code_watchers[i]) {
      73              interp->code_watchers[i] = callback;
      74              interp->active_code_watchers |= (1 << i);
      75              return i;
      76          }
      77      }
      78  
      79      PyErr_SetString(PyExc_RuntimeError, "no more code watcher IDs available");
      80      return -1;
      81  }
      82  
      83  static inline int
      84  validate_watcher_id(PyInterpreterState *interp, int watcher_id)
      85  {
      86      if (watcher_id < 0 || watcher_id >= CODE_MAX_WATCHERS) {
      87          PyErr_Format(PyExc_ValueError, "Invalid code watcher ID %d", watcher_id);
      88          return -1;
      89      }
      90      if (!interp->code_watchers[watcher_id]) {
      91          PyErr_Format(PyExc_ValueError, "No code watcher set for ID %d", watcher_id);
      92          return -1;
      93      }
      94      return 0;
      95  }
      96  
      97  int
      98  PyCode_ClearWatcher(int watcher_id)
      99  {
     100      PyInterpreterState *interp = _PyInterpreterState_GET();
     101      assert(interp->_initialized);
     102      if (validate_watcher_id(interp, watcher_id) < 0) {
     103          return -1;
     104      }
     105      interp->code_watchers[watcher_id] = NULL;
     106      interp->active_code_watchers &= ~(1 << watcher_id);
     107      return 0;
     108  }
     109  
     110  /******************
     111   * generic helpers
     112   ******************/
     113  
     114  /* all_name_chars(s): true iff s matches [a-zA-Z0-9_]* */
     115  static int
     116  all_name_chars(PyObject *o)
     117  {
     118      const unsigned char *s, *e;
     119  
     120      if (!PyUnicode_IS_ASCII(o))
     121          return 0;
     122  
     123      s = PyUnicode_1BYTE_DATA(o);
     124      e = s + PyUnicode_GET_LENGTH(o);
     125      for (; s != e; s++) {
     126          if (!Py_ISALNUM(*s) && *s != '_')
     127              return 0;
     128      }
     129      return 1;
     130  }
     131  
     132  static int
     133  intern_strings(PyObject *tuple)
     134  {
     135      Py_ssize_t i;
     136  
     137      for (i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {
     138          PyObject *v = PyTuple_GET_ITEM(tuple, i);
     139          if (v == NULL || !PyUnicode_CheckExact(v)) {
     140              PyErr_SetString(PyExc_SystemError,
     141                              "non-string found in code slot");
     142              return -1;
     143          }
     144          PyUnicode_InternInPlace(&_PyTuple_ITEMS(tuple)[i]);
     145      }
     146      return 0;
     147  }
     148  
     149  /* Intern selected string constants */
     150  static int
     151  intern_string_constants(PyObject *tuple, int *modified)
     152  {
     153      for (Py_ssize_t i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {
     154          PyObject *v = PyTuple_GET_ITEM(tuple, i);
     155          if (PyUnicode_CheckExact(v)) {
     156              if (PyUnicode_READY(v) == -1) {
     157                  return -1;
     158              }
     159  
     160              if (all_name_chars(v)) {
     161                  PyObject *w = v;
     162                  PyUnicode_InternInPlace(&v);
     163                  if (w != v) {
     164                      PyTuple_SET_ITEM(tuple, i, v);
     165                      if (modified) {
     166                          *modified = 1;
     167                      }
     168                  }
     169              }
     170          }
     171          else if (PyTuple_CheckExact(v)) {
     172              if (intern_string_constants(v, NULL) < 0) {
     173                  return -1;
     174              }
     175          }
     176          else if (PyFrozenSet_CheckExact(v)) {
     177              PyObject *w = v;
     178              PyObject *tmp = PySequence_Tuple(v);
     179              if (tmp == NULL) {
     180                  return -1;
     181              }
     182              int tmp_modified = 0;
     183              if (intern_string_constants(tmp, &tmp_modified) < 0) {
     184                  Py_DECREF(tmp);
     185                  return -1;
     186              }
     187              if (tmp_modified) {
     188                  v = PyFrozenSet_New(tmp);
     189                  if (v == NULL) {
     190                      Py_DECREF(tmp);
     191                      return -1;
     192                  }
     193  
     194                  PyTuple_SET_ITEM(tuple, i, v);
     195                  Py_DECREF(w);
     196                  if (modified) {
     197                      *modified = 1;
     198                  }
     199              }
     200              Py_DECREF(tmp);
     201          }
     202      }
     203      return 0;
     204  }
     205  
     206  /* Return a shallow copy of a tuple that is
     207     guaranteed to contain exact strings, by converting string subclasses
     208     to exact strings and complaining if a non-string is found. */
     209  static PyObject*
     210  validate_and_copy_tuple(PyObject *tup)
     211  {
     212      PyObject *newtuple;
     213      PyObject *item;
     214      Py_ssize_t i, len;
     215  
     216      len = PyTuple_GET_SIZE(tup);
     217      newtuple = PyTuple_New(len);
     218      if (newtuple == NULL)
     219          return NULL;
     220  
     221      for (i = 0; i < len; i++) {
     222          item = PyTuple_GET_ITEM(tup, i);
     223          if (PyUnicode_CheckExact(item)) {
     224              Py_INCREF(item);
     225          }
     226          else if (!PyUnicode_Check(item)) {
     227              PyErr_Format(
     228                  PyExc_TypeError,
     229                  "name tuples must contain only "
     230                  "strings, not '%.500s'",
     231                  Py_TYPE(item)->tp_name);
     232              Py_DECREF(newtuple);
     233              return NULL;
     234          }
     235          else {
     236              item = _PyUnicode_Copy(item);
     237              if (item == NULL) {
     238                  Py_DECREF(newtuple);
     239                  return NULL;
     240              }
     241          }
     242          PyTuple_SET_ITEM(newtuple, i, item);
     243      }
     244  
     245      return newtuple;
     246  }
     247  
     248  static int
     249  init_co_cached(PyCodeObject *self) {
     250      if (self->_co_cached == NULL) {
     251          self->_co_cached = PyMem_New(_PyCoCached, 1);
     252          if (self->_co_cached == NULL) {
     253              PyErr_NoMemory();
     254              return -1;
     255          }
     256          self->_co_cached->_co_code = NULL;
     257          self->_co_cached->_co_cellvars = NULL;
     258          self->_co_cached->_co_freevars = NULL;
     259          self->_co_cached->_co_varnames = NULL;
     260      }
     261      return 0;
     262  
     263  }
     264  /******************
     265   * _PyCode_New()
     266   ******************/
     267  
     268  // This is also used in compile.c.
     269  void
     270  _Py_set_localsplus_info(int offset, PyObject *name, _PyLocals_Kind kind,
     271                          PyObject *names, PyObject *kinds)
     272  {
     273      PyTuple_SET_ITEM(names, offset, Py_NewRef(name));
     274      _PyLocals_SetKind(kinds, offset, kind);
     275  }
     276  
     277  static void
     278  get_localsplus_counts(PyObject *names, PyObject *kinds,
     279                        int *pnlocals, int *pncellvars,
     280                        int *pnfreevars)
     281  {
     282      int nlocals = 0;
     283      int ncellvars = 0;
     284      int nfreevars = 0;
     285      Py_ssize_t nlocalsplus = PyTuple_GET_SIZE(names);
     286      for (int i = 0; i < nlocalsplus; i++) {
     287          _PyLocals_Kind kind = _PyLocals_GetKind(kinds, i);
     288          if (kind & CO_FAST_LOCAL) {
     289              nlocals += 1;
     290              if (kind & CO_FAST_CELL) {
     291                  ncellvars += 1;
     292              }
     293          }
     294          else if (kind & CO_FAST_CELL) {
     295              ncellvars += 1;
     296          }
     297          else if (kind & CO_FAST_FREE) {
     298              nfreevars += 1;
     299          }
     300      }
     301      if (pnlocals != NULL) {
     302          *pnlocals = nlocals;
     303      }
     304      if (pncellvars != NULL) {
     305          *pncellvars = ncellvars;
     306      }
     307      if (pnfreevars != NULL) {
     308          *pnfreevars = nfreevars;
     309      }
     310  }
     311  
     312  static PyObject *
     313  get_localsplus_names(PyCodeObject *co, _PyLocals_Kind kind, int num)
     314  {
     315      PyObject *names = PyTuple_New(num);
     316      if (names == NULL) {
     317          return NULL;
     318      }
     319      int index = 0;
     320      for (int offset = 0; offset < co->co_nlocalsplus; offset++) {
     321          _PyLocals_Kind k = _PyLocals_GetKind(co->co_localspluskinds, offset);
     322          if ((k & kind) == 0) {
     323              continue;
     324          }
     325          assert(index < num);
     326          PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, offset);
     327          PyTuple_SET_ITEM(names, index, Py_NewRef(name));
     328          index += 1;
     329      }
     330      assert(index == num);
     331      return names;
     332  }
     333  
     334  int
     335  _PyCode_Validate(struct _PyCodeConstructor *con)
     336  {
     337      /* Check argument types */
     338      if (con->argcount < con->posonlyargcount || con->posonlyargcount < 0 ||
     339          con->kwonlyargcount < 0 ||
     340          con->stacksize < 0 || con->flags < 0 ||
     341          con->code == NULL || !PyBytes_Check(con->code) ||
     342          con->consts == NULL || !PyTuple_Check(con->consts) ||
     343          con->names == NULL || !PyTuple_Check(con->names) ||
     344          con->localsplusnames == NULL || !PyTuple_Check(con->localsplusnames) ||
     345          con->localspluskinds == NULL || !PyBytes_Check(con->localspluskinds) ||
     346          PyTuple_GET_SIZE(con->localsplusnames)
     347              != PyBytes_GET_SIZE(con->localspluskinds) ||
     348          con->name == NULL || !PyUnicode_Check(con->name) ||
     349          con->qualname == NULL || !PyUnicode_Check(con->qualname) ||
     350          con->filename == NULL || !PyUnicode_Check(con->filename) ||
     351          con->linetable == NULL || !PyBytes_Check(con->linetable) ||
     352          con->exceptiontable == NULL || !PyBytes_Check(con->exceptiontable)
     353          ) {
     354          PyErr_BadInternalCall();
     355          return -1;
     356      }
     357  
     358      /* Make sure that code is indexable with an int, this is
     359         a long running assumption in ceval.c and many parts of
     360         the interpreter. */
     361      if (PyBytes_GET_SIZE(con->code) > INT_MAX) {
     362          PyErr_SetString(PyExc_OverflowError,
     363                          "code: co_code larger than INT_MAX");
     364          return -1;
     365      }
     366      if (PyBytes_GET_SIZE(con->code) % sizeof(_Py_CODEUNIT) != 0 ||
     367          !_Py_IS_ALIGNED(PyBytes_AS_STRING(con->code), sizeof(_Py_CODEUNIT))
     368          ) {
     369          PyErr_SetString(PyExc_ValueError, "code: co_code is malformed");
     370          return -1;
     371      }
     372  
     373      /* Ensure that the co_varnames has enough names to cover the arg counts.
     374       * Note that totalargs = nlocals - nplainlocals.  We check nplainlocals
     375       * here to avoid the possibility of overflow (however remote). */
     376      int nlocals;
     377      get_localsplus_counts(con->localsplusnames, con->localspluskinds,
     378                            &nlocals, NULL, NULL);
     379      int nplainlocals = nlocals -
     380                         con->argcount -
     381                         con->kwonlyargcount -
     382                         ((con->flags & CO_VARARGS) != 0) -
     383                         ((con->flags & CO_VARKEYWORDS) != 0);
     384      if (nplainlocals < 0) {
     385          PyErr_SetString(PyExc_ValueError, "code: co_varnames is too small");
     386          return -1;
     387      }
     388  
     389      return 0;
     390  }
     391  
     392  extern void _PyCode_Quicken(PyCodeObject *code);
     393  
     394  static void
     395  init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
     396  {
     397      int nlocalsplus = (int)PyTuple_GET_SIZE(con->localsplusnames);
     398      int nlocals, ncellvars, nfreevars;
     399      get_localsplus_counts(con->localsplusnames, con->localspluskinds,
     400                            &nlocals, &ncellvars, &nfreevars);
     401  
     402      co->co_filename = Py_NewRef(con->filename);
     403      co->co_name = Py_NewRef(con->name);
     404      co->co_qualname = Py_NewRef(con->qualname);
     405      co->co_flags = con->flags;
     406  
     407      co->co_firstlineno = con->firstlineno;
     408      co->co_linetable = Py_NewRef(con->linetable);
     409  
     410      co->co_consts = Py_NewRef(con->consts);
     411      co->co_names = Py_NewRef(con->names);
     412  
     413      co->co_localsplusnames = Py_NewRef(con->localsplusnames);
     414      co->co_localspluskinds = Py_NewRef(con->localspluskinds);
     415  
     416      co->co_argcount = con->argcount;
     417      co->co_posonlyargcount = con->posonlyargcount;
     418      co->co_kwonlyargcount = con->kwonlyargcount;
     419  
     420      co->co_stacksize = con->stacksize;
     421  
     422      co->co_exceptiontable = Py_NewRef(con->exceptiontable);
     423  
     424      /* derived values */
     425      co->co_nlocalsplus = nlocalsplus;
     426      co->co_nlocals = nlocals;
     427      co->co_framesize = nlocalsplus + con->stacksize + FRAME_SPECIALS_SIZE;
     428      co->co_ncellvars = ncellvars;
     429      co->co_nfreevars = nfreevars;
     430      co->co_version = _Py_next_func_version;
     431      if (_Py_next_func_version != 0) {
     432          _Py_next_func_version++;
     433      }
     434      co->_co_monitoring = NULL;
     435      co->_co_instrumentation_version = 0;
     436      /* not set */
     437      co->co_weakreflist = NULL;
     438      co->co_extra = NULL;
     439      co->_co_cached = NULL;
     440  
     441      memcpy(_PyCode_CODE(co), PyBytes_AS_STRING(con->code),
     442             PyBytes_GET_SIZE(con->code));
     443      int entry_point = 0;
     444      while (entry_point < Py_SIZE(co) &&
     445          _PyCode_CODE(co)[entry_point].op.code != RESUME) {
     446          entry_point++;
     447      }
     448      co->_co_firsttraceable = entry_point;
     449      _PyCode_Quicken(co);
     450      notify_code_watchers(PY_CODE_EVENT_CREATE, co);
     451  }
     452  
     453  static int
     454  scan_varint(const uint8_t *ptr)
     455  {
     456      unsigned int read = *ptr++;
     457      unsigned int val = read & 63;
     458      unsigned int shift = 0;
     459      while (read & 64) {
     460          read = *ptr++;
     461          shift += 6;
     462          val |= (read & 63) << shift;
     463      }
     464      return val;
     465  }
     466  
     467  static int
     468  scan_signed_varint(const uint8_t *ptr)
     469  {
     470      unsigned int uval = scan_varint(ptr);
     471      if (uval & 1) {
     472          return -(int)(uval >> 1);
     473      }
     474      else {
     475          return uval >> 1;
     476      }
     477  }
     478  
     479  static int
     480  get_line_delta(const uint8_t *ptr)
     481  {
     482      int code = ((*ptr) >> 3) & 15;
     483      switch (code) {
     484          case PY_CODE_LOCATION_INFO_NONE:
     485              return 0;
     486          case PY_CODE_LOCATION_INFO_NO_COLUMNS:
     487          case PY_CODE_LOCATION_INFO_LONG:
     488              return scan_signed_varint(ptr+1);
     489          case PY_CODE_LOCATION_INFO_ONE_LINE0:
     490              return 0;
     491          case PY_CODE_LOCATION_INFO_ONE_LINE1:
     492              return 1;
     493          case PY_CODE_LOCATION_INFO_ONE_LINE2:
     494              return 2;
     495          default:
     496              /* Same line */
     497              return 0;
     498      }
     499  }
     500  
     501  static PyObject *
     502  remove_column_info(PyObject *locations)
     503  {
     504      int offset = 0;
     505      const uint8_t *data = (const uint8_t *)PyBytes_AS_STRING(locations);
     506      PyObject *res = PyBytes_FromStringAndSize(NULL, 32);
     507      if (res == NULL) {
     508          PyErr_NoMemory();
     509          return NULL;
     510      }
     511      uint8_t *output = (uint8_t *)PyBytes_AS_STRING(res);
     512      while (offset < PyBytes_GET_SIZE(locations)) {
     513          Py_ssize_t write_offset = output - (uint8_t *)PyBytes_AS_STRING(res);
     514          if (write_offset + 16 >= PyBytes_GET_SIZE(res)) {
     515              if (_PyBytes_Resize(&res, PyBytes_GET_SIZE(res) * 2) < 0) {
     516                  return NULL;
     517              }
     518              output = (uint8_t *)PyBytes_AS_STRING(res) + write_offset;
     519          }
     520          int code = (data[offset] >> 3) & 15;
     521          if (code == PY_CODE_LOCATION_INFO_NONE) {
     522              *output++ = data[offset];
     523          }
     524          else {
     525              int blength = (data[offset] & 7)+1;
     526              output += write_location_entry_start(
     527                  output, PY_CODE_LOCATION_INFO_NO_COLUMNS, blength);
     528              int ldelta = get_line_delta(&data[offset]);
     529              output += write_signed_varint(output, ldelta);
     530          }
     531          offset++;
     532          while (offset < PyBytes_GET_SIZE(locations) &&
     533              (data[offset] & 128) == 0) {
     534              offset++;
     535          }
     536      }
     537      Py_ssize_t write_offset = output - (uint8_t *)PyBytes_AS_STRING(res);
     538      if (_PyBytes_Resize(&res, write_offset)) {
     539          return NULL;
     540      }
     541      return res;
     542  }
     543  
     544  /* The caller is responsible for ensuring that the given data is valid. */
     545  
     546  PyCodeObject *
     547  _PyCode_New(struct _PyCodeConstructor *con)
     548  {
     549      /* Ensure that strings are ready Unicode string */
     550      if (PyUnicode_READY(con->name) < 0) {
     551          return NULL;
     552      }
     553      if (PyUnicode_READY(con->qualname) < 0) {
     554          return NULL;
     555      }
     556      if (PyUnicode_READY(con->filename) < 0) {
     557          return NULL;
     558      }
     559  
     560      if (intern_strings(con->names) < 0) {
     561          return NULL;
     562      }
     563      if (intern_string_constants(con->consts, NULL) < 0) {
     564          return NULL;
     565      }
     566      if (intern_strings(con->localsplusnames) < 0) {
     567          return NULL;
     568      }
     569  
     570      PyObject *replacement_locations = NULL;
     571      // Compact the linetable if we are opted out of debug
     572      // ranges.
     573      if (!_Py_GetConfig()->code_debug_ranges) {
     574          replacement_locations = remove_column_info(con->linetable);
     575          if (replacement_locations == NULL) {
     576              return NULL;
     577          }
     578          con->linetable = replacement_locations;
     579      }
     580  
     581      Py_ssize_t size = PyBytes_GET_SIZE(con->code) / sizeof(_Py_CODEUNIT);
     582      PyCodeObject *co = PyObject_NewVar(PyCodeObject, &PyCode_Type, size);
     583      if (co == NULL) {
     584          Py_XDECREF(replacement_locations);
     585          PyErr_NoMemory();
     586          return NULL;
     587      }
     588      init_code(co, con);
     589      Py_XDECREF(replacement_locations);
     590      return co;
     591  }
     592  
     593  
     594  /******************
     595   * the legacy "constructors"
     596   ******************/
     597  
     598  PyCodeObject *
     599  PyUnstable_Code_NewWithPosOnlyArgs(
     600                            int argcount, int posonlyargcount, int kwonlyargcount,
     601                            int nlocals, int stacksize, int flags,
     602                            PyObject *code, PyObject *consts, PyObject *names,
     603                            PyObject *varnames, PyObject *freevars, PyObject *cellvars,
     604                            PyObject *filename, PyObject *name,
     605                            PyObject *qualname, int firstlineno,
     606                            PyObject *linetable,
     607                            PyObject *exceptiontable)
     608  {
     609      PyCodeObject *co = NULL;
     610      PyObject *localsplusnames = NULL;
     611      PyObject *localspluskinds = NULL;
     612  
     613      if (varnames == NULL || !PyTuple_Check(varnames) ||
     614          cellvars == NULL || !PyTuple_Check(cellvars) ||
     615          freevars == NULL || !PyTuple_Check(freevars)
     616          ) {
     617          PyErr_BadInternalCall();
     618          return NULL;
     619      }
     620  
     621      // Set the "fast locals plus" info.
     622      int nvarnames = (int)PyTuple_GET_SIZE(varnames);
     623      int ncellvars = (int)PyTuple_GET_SIZE(cellvars);
     624      int nfreevars = (int)PyTuple_GET_SIZE(freevars);
     625      int nlocalsplus = nvarnames + ncellvars + nfreevars;
     626      localsplusnames = PyTuple_New(nlocalsplus);
     627      if (localsplusnames == NULL) {
     628          goto error;
     629      }
     630      localspluskinds = PyBytes_FromStringAndSize(NULL, nlocalsplus);
     631      if (localspluskinds == NULL) {
     632          goto error;
     633      }
     634      int  offset = 0;
     635      for (int i = 0; i < nvarnames; i++, offset++) {
     636          PyObject *name = PyTuple_GET_ITEM(varnames, i);
     637          _Py_set_localsplus_info(offset, name, CO_FAST_LOCAL,
     638                                 localsplusnames, localspluskinds);
     639      }
     640      for (int i = 0; i < ncellvars; i++, offset++) {
     641          PyObject *name = PyTuple_GET_ITEM(cellvars, i);
     642          int argoffset = -1;
     643          for (int j = 0; j < nvarnames; j++) {
     644              int cmp = PyUnicode_Compare(PyTuple_GET_ITEM(varnames, j),
     645                                          name);
     646              assert(!PyErr_Occurred());
     647              if (cmp == 0) {
     648                  argoffset = j;
     649                  break;
     650              }
     651          }
     652          if (argoffset >= 0) {
     653              // Merge the localsplus indices.
     654              nlocalsplus -= 1;
     655              offset -= 1;
     656              _PyLocals_Kind kind = _PyLocals_GetKind(localspluskinds, argoffset);
     657              _PyLocals_SetKind(localspluskinds, argoffset, kind | CO_FAST_CELL);
     658              continue;
     659          }
     660          _Py_set_localsplus_info(offset, name, CO_FAST_CELL,
     661                                 localsplusnames, localspluskinds);
     662      }
     663      for (int i = 0; i < nfreevars; i++, offset++) {
     664          PyObject *name = PyTuple_GET_ITEM(freevars, i);
     665          _Py_set_localsplus_info(offset, name, CO_FAST_FREE,
     666                                 localsplusnames, localspluskinds);
     667      }
     668      // If any cells were args then nlocalsplus will have shrunk.
     669      if (nlocalsplus != PyTuple_GET_SIZE(localsplusnames)) {
     670          if (_PyTuple_Resize(&localsplusnames, nlocalsplus) < 0
     671                  || _PyBytes_Resize(&localspluskinds, nlocalsplus) < 0) {
     672              goto error;
     673          }
     674      }
     675  
     676      struct _PyCodeConstructor con = {
     677          .filename = filename,
     678          .name = name,
     679          .qualname = qualname,
     680          .flags = flags,
     681  
     682          .code = code,
     683          .firstlineno = firstlineno,
     684          .linetable = linetable,
     685  
     686          .consts = consts,
     687          .names = names,
     688  
     689          .localsplusnames = localsplusnames,
     690          .localspluskinds = localspluskinds,
     691  
     692          .argcount = argcount,
     693          .posonlyargcount = posonlyargcount,
     694          .kwonlyargcount = kwonlyargcount,
     695  
     696          .stacksize = stacksize,
     697  
     698          .exceptiontable = exceptiontable,
     699      };
     700  
     701      if (_PyCode_Validate(&con) < 0) {
     702          goto error;
     703      }
     704      assert(PyBytes_GET_SIZE(code) % sizeof(_Py_CODEUNIT) == 0);
     705      assert(_Py_IS_ALIGNED(PyBytes_AS_STRING(code), sizeof(_Py_CODEUNIT)));
     706      if (nlocals != PyTuple_GET_SIZE(varnames)) {
     707          PyErr_SetString(PyExc_ValueError,
     708                          "code: co_nlocals != len(co_varnames)");
     709          goto error;
     710      }
     711  
     712      co = _PyCode_New(&con);
     713      if (co == NULL) {
     714          goto error;
     715      }
     716  
     717  error:
     718      Py_XDECREF(localsplusnames);
     719      Py_XDECREF(localspluskinds);
     720      return co;
     721  }
     722  
     723  PyCodeObject *
     724  PyUnstable_Code_New(int argcount, int kwonlyargcount,
     725             int nlocals, int stacksize, int flags,
     726             PyObject *code, PyObject *consts, PyObject *names,
     727             PyObject *varnames, PyObject *freevars, PyObject *cellvars,
     728             PyObject *filename, PyObject *name, PyObject *qualname,
     729             int firstlineno,
     730             PyObject *linetable,
     731             PyObject *exceptiontable)
     732  {
     733      return PyCode_NewWithPosOnlyArgs(argcount, 0, kwonlyargcount, nlocals,
     734                                       stacksize, flags, code, consts, names,
     735                                       varnames, freevars, cellvars, filename,
     736                                       name, qualname, firstlineno,
     737                                       linetable,
     738                                       exceptiontable);
     739  }
     740  
     741  // NOTE: When modifying the construction of PyCode_NewEmpty, please also change
     742  // test.test_code.CodeLocationTest.test_code_new_empty to keep it in sync!
     743  
     744  static const uint8_t assert0[6] = {
     745      RESUME, 0,
     746      LOAD_ASSERTION_ERROR, 0,
     747      RAISE_VARARGS, 1
     748  };
     749  
     750  static const uint8_t linetable[2] = {
     751      (1 << 7)  // New entry.
     752      | (PY_CODE_LOCATION_INFO_NO_COLUMNS << 3)
     753      | (3 - 1),  // Three code units.
     754      0,  // Offset from co_firstlineno.
     755  };
     756  
     757  PyCodeObject *
     758  PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
     759  {
     760      PyObject *nulltuple = NULL;
     761      PyObject *filename_ob = NULL;
     762      PyObject *funcname_ob = NULL;
     763      PyObject *code_ob = NULL;
     764      PyObject *linetable_ob = NULL;
     765      PyCodeObject *result = NULL;
     766  
     767      nulltuple = PyTuple_New(0);
     768      if (nulltuple == NULL) {
     769          goto failed;
     770      }
     771      funcname_ob = PyUnicode_FromString(funcname);
     772      if (funcname_ob == NULL) {
     773          goto failed;
     774      }
     775      filename_ob = PyUnicode_DecodeFSDefault(filename);
     776      if (filename_ob == NULL) {
     777          goto failed;
     778      }
     779      code_ob = PyBytes_FromStringAndSize((const char *)assert0, 6);
     780      if (code_ob == NULL) {
     781          goto failed;
     782      }
     783      linetable_ob = PyBytes_FromStringAndSize((const char *)linetable, 2);
     784      if (linetable_ob == NULL) {
     785          goto failed;
     786      }
     787  
     788  #define emptystring (PyObject *)&_Py_SINGLETON(bytes_empty)
     789      struct _PyCodeConstructor con = {
     790          .filename = filename_ob,
     791          .name = funcname_ob,
     792          .qualname = funcname_ob,
     793          .code = code_ob,
     794          .firstlineno = firstlineno,
     795          .linetable = linetable_ob,
     796          .consts = nulltuple,
     797          .names = nulltuple,
     798          .localsplusnames = nulltuple,
     799          .localspluskinds = emptystring,
     800          .exceptiontable = emptystring,
     801          .stacksize = 1,
     802      };
     803      result = _PyCode_New(&con);
     804  
     805  failed:
     806      Py_XDECREF(nulltuple);
     807      Py_XDECREF(funcname_ob);
     808      Py_XDECREF(filename_ob);
     809      Py_XDECREF(code_ob);
     810      Py_XDECREF(linetable_ob);
     811      return result;
     812  }
     813  
     814  
     815  /******************
     816   * source location tracking (co_lines/co_positions)
     817   ******************/
     818  
     819  int
     820  PyCode_Addr2Line(PyCodeObject *co, int addrq)
     821  {
     822      if (addrq < 0) {
     823          return co->co_firstlineno;
     824      }
     825      assert(addrq >= 0 && addrq < _PyCode_NBYTES(co));
     826      PyCodeAddressRange bounds;
     827      _PyCode_InitAddressRange(co, &bounds);
     828      return _PyCode_CheckLineNumber(addrq, &bounds);
     829  }
     830  
     831  void
     832  _PyLineTable_InitAddressRange(const char *linetable, Py_ssize_t length, int firstlineno, PyCodeAddressRange *range)
     833  {
     834      range->opaque.lo_next = (const uint8_t *)linetable;
     835      range->opaque.limit = range->opaque.lo_next + length;
     836      range->ar_start = -1;
     837      range->ar_end = 0;
     838      range->opaque.computed_line = firstlineno;
     839      range->ar_line = -1;
     840  }
     841  
     842  int
     843  _PyCode_InitAddressRange(PyCodeObject* co, PyCodeAddressRange *bounds)
     844  {
     845      assert(co->co_linetable != NULL);
     846      const char *linetable = PyBytes_AS_STRING(co->co_linetable);
     847      Py_ssize_t length = PyBytes_GET_SIZE(co->co_linetable);
     848      _PyLineTable_InitAddressRange(linetable, length, co->co_firstlineno, bounds);
     849      return bounds->ar_line;
     850  }
     851  
     852  /* Update *bounds to describe the first and one-past-the-last instructions in
     853     the same line as lasti.  Return the number of that line, or -1 if lasti is out of bounds. */
     854  int
     855  _PyCode_CheckLineNumber(int lasti, PyCodeAddressRange *bounds)
     856  {
     857      while (bounds->ar_end <= lasti) {
     858          if (!_PyLineTable_NextAddressRange(bounds)) {
     859              return -1;
     860          }
     861      }
     862      while (bounds->ar_start > lasti) {
     863          if (!_PyLineTable_PreviousAddressRange(bounds)) {
     864              return -1;
     865          }
     866      }
     867      return bounds->ar_line;
     868  }
     869  
     870  static int
     871  is_no_line_marker(uint8_t b)
     872  {
     873      return (b >> 3) == 0x1f;
     874  }
     875  
     876  
     877  #define ASSERT_VALID_BOUNDS(bounds) \
     878      assert(bounds->opaque.lo_next <=  bounds->opaque.limit && \
     879          (bounds->ar_line == -1 || bounds->ar_line == bounds->opaque.computed_line) && \
     880          (bounds->opaque.lo_next == bounds->opaque.limit || \
     881          (*bounds->opaque.lo_next) & 128))
     882  
     883  static int
     884  next_code_delta(PyCodeAddressRange *bounds)
     885  {
     886      assert((*bounds->opaque.lo_next) & 128);
     887      return (((*bounds->opaque.lo_next) & 7) + 1) * sizeof(_Py_CODEUNIT);
     888  }
     889  
     890  static int
     891  previous_code_delta(PyCodeAddressRange *bounds)
     892  {
     893      if (bounds->ar_start == 0) {
     894          // If we looking at the first entry, the
     895          // "previous" entry has an implicit length of 1.
     896          return 1;
     897      }
     898      const uint8_t *ptr = bounds->opaque.lo_next-1;
     899      while (((*ptr) & 128) == 0) {
     900          ptr--;
     901      }
     902      return (((*ptr) & 7) + 1) * sizeof(_Py_CODEUNIT);
     903  }
     904  
     905  static int
     906  read_byte(PyCodeAddressRange *bounds)
     907  {
     908      return *bounds->opaque.lo_next++;
     909  }
     910  
     911  static int
     912  read_varint(PyCodeAddressRange *bounds)
     913  {
     914      unsigned int read = read_byte(bounds);
     915      unsigned int val = read & 63;
     916      unsigned int shift = 0;
     917      while (read & 64) {
     918          read = read_byte(bounds);
     919          shift += 6;
     920          val |= (read & 63) << shift;
     921      }
     922      return val;
     923  }
     924  
     925  static int
     926  read_signed_varint(PyCodeAddressRange *bounds)
     927  {
     928      unsigned int uval = read_varint(bounds);
     929      if (uval & 1) {
     930          return -(int)(uval >> 1);
     931      }
     932      else {
     933          return uval >> 1;
     934      }
     935  }
     936  
     937  static void
     938  retreat(PyCodeAddressRange *bounds)
     939  {
     940      ASSERT_VALID_BOUNDS(bounds);
     941      assert(bounds->ar_start >= 0);
     942      do {
     943          bounds->opaque.lo_next--;
     944      } while (((*bounds->opaque.lo_next) & 128) == 0);
     945      bounds->opaque.computed_line -= get_line_delta(bounds->opaque.lo_next);
     946      bounds->ar_end = bounds->ar_start;
     947      bounds->ar_start -= previous_code_delta(bounds);
     948      if (is_no_line_marker(bounds->opaque.lo_next[-1])) {
     949          bounds->ar_line = -1;
     950      }
     951      else {
     952          bounds->ar_line = bounds->opaque.computed_line;
     953      }
     954      ASSERT_VALID_BOUNDS(bounds);
     955  }
     956  
     957  static void
     958  advance(PyCodeAddressRange *bounds)
     959  {
     960      ASSERT_VALID_BOUNDS(bounds);
     961      bounds->opaque.computed_line += get_line_delta(bounds->opaque.lo_next);
     962      if (is_no_line_marker(*bounds->opaque.lo_next)) {
     963          bounds->ar_line = -1;
     964      }
     965      else {
     966          bounds->ar_line = bounds->opaque.computed_line;
     967      }
     968      bounds->ar_start = bounds->ar_end;
     969      bounds->ar_end += next_code_delta(bounds);
     970      do {
     971          bounds->opaque.lo_next++;
     972      } while (bounds->opaque.lo_next < bounds->opaque.limit &&
     973          ((*bounds->opaque.lo_next) & 128) == 0);
     974      ASSERT_VALID_BOUNDS(bounds);
     975  }
     976  
     977  static void
     978  advance_with_locations(PyCodeAddressRange *bounds, int *endline, int *column, int *endcolumn)
     979  {
     980      ASSERT_VALID_BOUNDS(bounds);
     981      int first_byte = read_byte(bounds);
     982      int code = (first_byte >> 3) & 15;
     983      bounds->ar_start = bounds->ar_end;
     984      bounds->ar_end = bounds->ar_start + ((first_byte & 7) + 1) * sizeof(_Py_CODEUNIT);
     985      switch(code) {
     986          case PY_CODE_LOCATION_INFO_NONE:
     987              bounds->ar_line = *endline = -1;
     988              *column =  *endcolumn = -1;
     989              break;
     990          case PY_CODE_LOCATION_INFO_LONG:
     991          {
     992              bounds->opaque.computed_line += read_signed_varint(bounds);
     993              bounds->ar_line = bounds->opaque.computed_line;
     994              *endline = bounds->ar_line + read_varint(bounds);
     995              *column = read_varint(bounds)-1;
     996              *endcolumn = read_varint(bounds)-1;
     997              break;
     998          }
     999          case PY_CODE_LOCATION_INFO_NO_COLUMNS:
    1000          {
    1001              /* No column */
    1002              bounds->opaque.computed_line += read_signed_varint(bounds);
    1003              *endline = bounds->ar_line = bounds->opaque.computed_line;
    1004              *column = *endcolumn = -1;
    1005              break;
    1006          }
    1007          case PY_CODE_LOCATION_INFO_ONE_LINE0:
    1008          case PY_CODE_LOCATION_INFO_ONE_LINE1:
    1009          case PY_CODE_LOCATION_INFO_ONE_LINE2:
    1010          {
    1011              /* one line form */
    1012              int line_delta = code - 10;
    1013              bounds->opaque.computed_line += line_delta;
    1014              *endline = bounds->ar_line = bounds->opaque.computed_line;
    1015              *column = read_byte(bounds);
    1016              *endcolumn = read_byte(bounds);
    1017              break;
    1018          }
    1019          default:
    1020          {
    1021              /* Short forms */
    1022              int second_byte = read_byte(bounds);
    1023              assert((second_byte & 128) == 0);
    1024              *endline = bounds->ar_line = bounds->opaque.computed_line;
    1025              *column = code << 3 | (second_byte >> 4);
    1026              *endcolumn = *column + (second_byte & 15);
    1027          }
    1028      }
    1029      ASSERT_VALID_BOUNDS(bounds);
    1030  }
    1031  int
    1032  PyCode_Addr2Location(PyCodeObject *co, int addrq,
    1033                       int *start_line, int *start_column,
    1034                       int *end_line, int *end_column)
    1035  {
    1036      if (addrq < 0) {
    1037          *start_line = *end_line = co->co_firstlineno;
    1038          *start_column = *end_column = 0;
    1039          return 1;
    1040      }
    1041      assert(addrq >= 0 && addrq < _PyCode_NBYTES(co));
    1042      PyCodeAddressRange bounds;
    1043      _PyCode_InitAddressRange(co, &bounds);
    1044      _PyCode_CheckLineNumber(addrq, &bounds);
    1045      retreat(&bounds);
    1046      advance_with_locations(&bounds, end_line, start_column, end_column);
    1047      *start_line = bounds.ar_line;
    1048      return 1;
    1049  }
    1050  
    1051  
    1052  static inline int
    1053  at_end(PyCodeAddressRange *bounds) {
    1054      return bounds->opaque.lo_next >= bounds->opaque.limit;
    1055  }
    1056  
    1057  int
    1058  _PyLineTable_PreviousAddressRange(PyCodeAddressRange *range)
    1059  {
    1060      if (range->ar_start <= 0) {
    1061          return 0;
    1062      }
    1063      retreat(range);
    1064      assert(range->ar_end > range->ar_start);
    1065      return 1;
    1066  }
    1067  
    1068  int
    1069  _PyLineTable_NextAddressRange(PyCodeAddressRange *range)
    1070  {
    1071      if (at_end(range)) {
    1072          return 0;
    1073      }
    1074      advance(range);
    1075      assert(range->ar_end > range->ar_start);
    1076      return 1;
    1077  }
    1078  
    1079  static int
    1080  emit_pair(PyObject **bytes, int *offset, int a, int b)
    1081  {
    1082      Py_ssize_t len = PyBytes_GET_SIZE(*bytes);
    1083      if (*offset + 2 >= len) {
    1084          if (_PyBytes_Resize(bytes, len * 2) < 0)
    1085              return 0;
    1086      }
    1087      unsigned char *lnotab = (unsigned char *) PyBytes_AS_STRING(*bytes);
    1088      lnotab += *offset;
    1089      *lnotab++ = a;
    1090      *lnotab++ = b;
    1091      *offset += 2;
    1092      return 1;
    1093  }
    1094  
    1095  static int
    1096  emit_delta(PyObject **bytes, int bdelta, int ldelta, int *offset)
    1097  {
    1098      while (bdelta > 255) {
    1099          if (!emit_pair(bytes, offset, 255, 0)) {
    1100              return 0;
    1101          }
    1102          bdelta -= 255;
    1103      }
    1104      while (ldelta > 127) {
    1105          if (!emit_pair(bytes, offset, bdelta, 127)) {
    1106              return 0;
    1107          }
    1108          bdelta = 0;
    1109          ldelta -= 127;
    1110      }
    1111      while (ldelta < -128) {
    1112          if (!emit_pair(bytes, offset, bdelta, -128)) {
    1113              return 0;
    1114          }
    1115          bdelta = 0;
    1116          ldelta += 128;
    1117      }
    1118      return emit_pair(bytes, offset, bdelta, ldelta);
    1119  }
    1120  
    1121  static PyObject *
    1122  decode_linetable(PyCodeObject *code)
    1123  {
    1124      PyCodeAddressRange bounds;
    1125      PyObject *bytes;
    1126      int table_offset = 0;
    1127      int code_offset = 0;
    1128      int line = code->co_firstlineno;
    1129      bytes = PyBytes_FromStringAndSize(NULL, 64);
    1130      if (bytes == NULL) {
    1131          return NULL;
    1132      }
    1133      _PyCode_InitAddressRange(code, &bounds);
    1134      while (_PyLineTable_NextAddressRange(&bounds)) {
    1135          if (bounds.opaque.computed_line != line) {
    1136              int bdelta = bounds.ar_start - code_offset;
    1137              int ldelta = bounds.opaque.computed_line - line;
    1138              if (!emit_delta(&bytes, bdelta, ldelta, &table_offset)) {
    1139                  Py_DECREF(bytes);
    1140                  return NULL;
    1141              }
    1142              code_offset = bounds.ar_start;
    1143              line = bounds.opaque.computed_line;
    1144          }
    1145      }
    1146      _PyBytes_Resize(&bytes, table_offset);
    1147      return bytes;
    1148  }
    1149  
    1150  
    1151  typedef struct {
    1152      PyObject_HEAD
    1153      PyCodeObject *li_code;
    1154      PyCodeAddressRange li_line;
    1155  } lineiterator;
    1156  
    1157  
    1158  static void
    1159  lineiter_dealloc(lineiterator *li)
    1160  {
    1161      Py_DECREF(li->li_code);
    1162      Py_TYPE(li)->tp_free(li);
    1163  }
    1164  
    1165  static PyObject *
    1166  _source_offset_converter(int *value) {
    1167      if (*value == -1) {
    1168          Py_RETURN_NONE;
    1169      }
    1170      return PyLong_FromLong(*value);
    1171  }
    1172  
    1173  static PyObject *
    1174  lineiter_next(lineiterator *li)
    1175  {
    1176      PyCodeAddressRange *bounds = &li->li_line;
    1177      if (!_PyLineTable_NextAddressRange(bounds)) {
    1178          return NULL;
    1179      }
    1180      int start = bounds->ar_start;
    1181      int line = bounds->ar_line;
    1182      // Merge overlapping entries:
    1183      while (_PyLineTable_NextAddressRange(bounds)) {
    1184          if (bounds->ar_line != line) {
    1185              _PyLineTable_PreviousAddressRange(bounds);
    1186              break;
    1187          }
    1188      }
    1189      return Py_BuildValue("iiO&", start, bounds->ar_end,
    1190                           _source_offset_converter, &line);
    1191  }
    1192  
    1193  PyTypeObject _PyLineIterator = {
    1194      PyVarObject_HEAD_INIT(&PyType_Type, 0)
    1195      "line_iterator",                    /* tp_name */
    1196      sizeof(lineiterator),               /* tp_basicsize */
    1197      0,                                  /* tp_itemsize */
    1198      /* methods */
    1199      (destructor)lineiter_dealloc,       /* tp_dealloc */
    1200      0,                                  /* tp_vectorcall_offset */
    1201      0,                                  /* tp_getattr */
    1202      0,                                  /* tp_setattr */
    1203      0,                                  /* tp_as_async */
    1204      0,                                  /* tp_repr */
    1205      0,                                  /* tp_as_number */
    1206      0,                                  /* tp_as_sequence */
    1207      0,                                  /* tp_as_mapping */
    1208      0,                                  /* tp_hash */
    1209      0,                                  /* tp_call */
    1210      0,                                  /* tp_str */
    1211      0,                                  /* tp_getattro */
    1212      0,                                  /* tp_setattro */
    1213      0,                                  /* tp_as_buffer */
    1214      Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,       /* tp_flags */
    1215      0,                                  /* tp_doc */
    1216      0,                                  /* tp_traverse */
    1217      0,                                  /* tp_clear */
    1218      0,                                  /* tp_richcompare */
    1219      0,                                  /* tp_weaklistoffset */
    1220      PyObject_SelfIter,                  /* tp_iter */
    1221      (iternextfunc)lineiter_next,        /* tp_iternext */
    1222      0,                                  /* tp_methods */
    1223      0,                                  /* tp_members */
    1224      0,                                  /* tp_getset */
    1225      0,                                  /* tp_base */
    1226      0,                                  /* tp_dict */
    1227      0,                                  /* tp_descr_get */
    1228      0,                                  /* tp_descr_set */
    1229      0,                                  /* tp_dictoffset */
    1230      0,                                  /* tp_init */
    1231      0,                                  /* tp_alloc */
    1232      0,                                  /* tp_new */
    1233      PyObject_Del,                       /* tp_free */
    1234  };
    1235  
    1236  static lineiterator *
    1237  new_linesiterator(PyCodeObject *code)
    1238  {
    1239      lineiterator *li = (lineiterator *)PyType_GenericAlloc(&_PyLineIterator, 0);
    1240      if (li == NULL) {
    1241          return NULL;
    1242      }
    1243      li->li_code = (PyCodeObject*)Py_NewRef(code);
    1244      _PyCode_InitAddressRange(code, &li->li_line);
    1245      return li;
    1246  }
    1247  
    1248  /* co_positions iterator object. */
    1249  typedef struct {
    1250      PyObject_HEAD
    1251      PyCodeObject* pi_code;
    1252      PyCodeAddressRange pi_range;
    1253      int pi_offset;
    1254      int pi_endline;
    1255      int pi_column;
    1256      int pi_endcolumn;
    1257  } positionsiterator;
    1258  
    1259  static void
    1260  positionsiter_dealloc(positionsiterator* pi)
    1261  {
    1262      Py_DECREF(pi->pi_code);
    1263      Py_TYPE(pi)->tp_free(pi);
    1264  }
    1265  
    1266  static PyObject*
    1267  positionsiter_next(positionsiterator* pi)
    1268  {
    1269      if (pi->pi_offset >= pi->pi_range.ar_end) {
    1270          assert(pi->pi_offset == pi->pi_range.ar_end);
    1271          if (at_end(&pi->pi_range)) {
    1272              return NULL;
    1273          }
    1274          advance_with_locations(&pi->pi_range, &pi->pi_endline, &pi->pi_column, &pi->pi_endcolumn);
    1275      }
    1276      pi->pi_offset += 2;
    1277      return Py_BuildValue("(O&O&O&O&)",
    1278          _source_offset_converter, &pi->pi_range.ar_line,
    1279          _source_offset_converter, &pi->pi_endline,
    1280          _source_offset_converter, &pi->pi_column,
    1281          _source_offset_converter, &pi->pi_endcolumn);
    1282  }
    1283  
    1284  PyTypeObject _PyPositionsIterator = {
    1285      PyVarObject_HEAD_INIT(&PyType_Type, 0)
    1286      "positions_iterator",               /* tp_name */
    1287      sizeof(positionsiterator),          /* tp_basicsize */
    1288      0,                                  /* tp_itemsize */
    1289      /* methods */
    1290      (destructor)positionsiter_dealloc,  /* tp_dealloc */
    1291      0,                                  /* tp_vectorcall_offset */
    1292      0,                                  /* tp_getattr */
    1293      0,                                  /* tp_setattr */
    1294      0,                                  /* tp_as_async */
    1295      0,                                  /* tp_repr */
    1296      0,                                  /* tp_as_number */
    1297      0,                                  /* tp_as_sequence */
    1298      0,                                  /* tp_as_mapping */
    1299      0,                                  /* tp_hash */
    1300      0,                                  /* tp_call */
    1301      0,                                  /* tp_str */
    1302      0,                                  /* tp_getattro */
    1303      0,                                  /* tp_setattro */
    1304      0,                                  /* tp_as_buffer */
    1305      Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,       /* tp_flags */
    1306      0,                                  /* tp_doc */
    1307      0,                                  /* tp_traverse */
    1308      0,                                  /* tp_clear */
    1309      0,                                  /* tp_richcompare */
    1310      0,                                  /* tp_weaklistoffset */
    1311      PyObject_SelfIter,                  /* tp_iter */
    1312      (iternextfunc)positionsiter_next,   /* tp_iternext */
    1313      0,                                  /* tp_methods */
    1314      0,                                  /* tp_members */
    1315      0,                                  /* tp_getset */
    1316      0,                                  /* tp_base */
    1317      0,                                  /* tp_dict */
    1318      0,                                  /* tp_descr_get */
    1319      0,                                  /* tp_descr_set */
    1320      0,                                  /* tp_dictoffset */
    1321      0,                                  /* tp_init */
    1322      0,                                  /* tp_alloc */
    1323      0,                                  /* tp_new */
    1324      PyObject_Del,                       /* tp_free */
    1325  };
    1326  
    1327  static PyObject*
    1328  code_positionsiterator(PyCodeObject* code, PyObject* Py_UNUSED(args))
    1329  {
    1330      positionsiterator* pi = (positionsiterator*)PyType_GenericAlloc(&_PyPositionsIterator, 0);
    1331      if (pi == NULL) {
    1332          return NULL;
    1333      }
    1334      pi->pi_code = (PyCodeObject*)Py_NewRef(code);
    1335      _PyCode_InitAddressRange(code, &pi->pi_range);
    1336      pi->pi_offset = pi->pi_range.ar_end;
    1337      return (PyObject*)pi;
    1338  }
    1339  
    1340  
    1341  /******************
    1342   * "extra" frame eval info (see PEP 523)
    1343   ******************/
    1344  
    1345  /* Holder for co_extra information */
    1346  typedef struct {
    1347      Py_ssize_t ce_size;
    1348      void *ce_extras[1];
    1349  } _PyCodeObjectExtra;
    1350  
    1351  
    1352  int
    1353  PyUnstable_Code_GetExtra(PyObject *code, Py_ssize_t index, void **extra)
    1354  {
    1355      if (!PyCode_Check(code)) {
    1356          PyErr_BadInternalCall();
    1357          return -1;
    1358      }
    1359  
    1360      PyCodeObject *o = (PyCodeObject*) code;
    1361      _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra*) o->co_extra;
    1362  
    1363      if (co_extra == NULL || index < 0 || co_extra->ce_size <= index) {
    1364          *extra = NULL;
    1365          return 0;
    1366      }
    1367  
    1368      *extra = co_extra->ce_extras[index];
    1369      return 0;
    1370  }
    1371  
    1372  
    1373  int
    1374  PyUnstable_Code_SetExtra(PyObject *code, Py_ssize_t index, void *extra)
    1375  {
    1376      PyInterpreterState *interp = _PyInterpreterState_GET();
    1377  
    1378      if (!PyCode_Check(code) || index < 0 ||
    1379              index >= interp->co_extra_user_count) {
    1380          PyErr_BadInternalCall();
    1381          return -1;
    1382      }
    1383  
    1384      PyCodeObject *o = (PyCodeObject*) code;
    1385      _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra *) o->co_extra;
    1386  
    1387      if (co_extra == NULL || co_extra->ce_size <= index) {
    1388          Py_ssize_t i = (co_extra == NULL ? 0 : co_extra->ce_size);
    1389          co_extra = PyMem_Realloc(
    1390                  co_extra,
    1391                  sizeof(_PyCodeObjectExtra) +
    1392                  (interp->co_extra_user_count-1) * sizeof(void*));
    1393          if (co_extra == NULL) {
    1394              return -1;
    1395          }
    1396          for (; i < interp->co_extra_user_count; i++) {
    1397              co_extra->ce_extras[i] = NULL;
    1398          }
    1399          co_extra->ce_size = interp->co_extra_user_count;
    1400          o->co_extra = co_extra;
    1401      }
    1402  
    1403      if (co_extra->ce_extras[index] != NULL) {
    1404          freefunc free = interp->co_extra_freefuncs[index];
    1405          if (free != NULL) {
    1406              free(co_extra->ce_extras[index]);
    1407          }
    1408      }
    1409  
    1410      co_extra->ce_extras[index] = extra;
    1411      return 0;
    1412  }
    1413  
    1414  
    1415  /******************
    1416   * other PyCodeObject accessor functions
    1417   ******************/
    1418  
    1419  static PyObject *
    1420  get_cached_locals(PyCodeObject *co, PyObject **cached_field,
    1421      _PyLocals_Kind kind, int num)
    1422  {
    1423      assert(cached_field != NULL);
    1424      assert(co->_co_cached != NULL);
    1425      if (*cached_field != NULL) {
    1426          return Py_NewRef(*cached_field);
    1427      }
    1428      assert(*cached_field == NULL);
    1429      PyObject *varnames = get_localsplus_names(co, kind, num);
    1430      if (varnames == NULL) {
    1431          return NULL;
    1432      }
    1433      *cached_field = Py_NewRef(varnames);
    1434      return varnames;
    1435  }
    1436  
    1437  PyObject *
    1438  _PyCode_GetVarnames(PyCodeObject *co)
    1439  {
    1440      if (init_co_cached(co)) {
    1441          return NULL;
    1442      }
    1443      return get_cached_locals(co, &co->_co_cached->_co_varnames, CO_FAST_LOCAL, co->co_nlocals);
    1444  }
    1445  
    1446  PyObject *
    1447  PyCode_GetVarnames(PyCodeObject *code)
    1448  {
    1449      return _PyCode_GetVarnames(code);
    1450  }
    1451  
    1452  PyObject *
    1453  _PyCode_GetCellvars(PyCodeObject *co)
    1454  {
    1455      if (init_co_cached(co)) {
    1456          return NULL;
    1457      }
    1458      return get_cached_locals(co, &co->_co_cached->_co_cellvars, CO_FAST_CELL, co->co_ncellvars);
    1459  }
    1460  
    1461  PyObject *
    1462  PyCode_GetCellvars(PyCodeObject *code)
    1463  {
    1464      return _PyCode_GetCellvars(code);
    1465  }
    1466  
    1467  PyObject *
    1468  _PyCode_GetFreevars(PyCodeObject *co)
    1469  {
    1470      if (init_co_cached(co)) {
    1471          return NULL;
    1472      }
    1473      return get_cached_locals(co, &co->_co_cached->_co_freevars, CO_FAST_FREE, co->co_nfreevars);
    1474  }
    1475  
    1476  PyObject *
    1477  PyCode_GetFreevars(PyCodeObject *code)
    1478  {
    1479      return _PyCode_GetFreevars(code);
    1480  }
    1481  
    1482  static void
    1483  deopt_code(PyCodeObject *code, _Py_CODEUNIT *instructions)
    1484  {
    1485      Py_ssize_t len = Py_SIZE(code);
    1486      for (int i = 0; i < len; i++) {
    1487          int opcode = _Py_GetBaseOpcode(code, i);
    1488          int caches = _PyOpcode_Caches[opcode];
    1489          instructions[i].op.code = opcode;
    1490          for (int j = 1; j <= caches; j++) {
    1491              instructions[i+j].cache = 0;
    1492          }
    1493          i += caches;
    1494      }
    1495  }
    1496  
    1497  PyObject *
    1498  _PyCode_GetCode(PyCodeObject *co)
    1499  {
    1500      if (init_co_cached(co)) {
    1501          return NULL;
    1502      }
    1503      if (co->_co_cached->_co_code != NULL) {
    1504          return Py_NewRef(co->_co_cached->_co_code);
    1505      }
    1506      PyObject *code = PyBytes_FromStringAndSize((const char *)_PyCode_CODE(co),
    1507                                                 _PyCode_NBYTES(co));
    1508      if (code == NULL) {
    1509          return NULL;
    1510      }
    1511      deopt_code(co, (_Py_CODEUNIT *)PyBytes_AS_STRING(code));
    1512      assert(co->_co_cached->_co_code == NULL);
    1513      co->_co_cached->_co_code = Py_NewRef(code);
    1514      return code;
    1515  }
    1516  
    1517  PyObject *
    1518  PyCode_GetCode(PyCodeObject *co)
    1519  {
    1520      return _PyCode_GetCode(co);
    1521  }
    1522  
    1523  /******************
    1524   * PyCode_Type
    1525   ******************/
    1526  
    1527  /*[clinic input]
    1528  class code "PyCodeObject *" "&PyCode_Type"
    1529  [clinic start generated code]*/
    1530  /*[clinic end generated code: output=da39a3ee5e6b4b0d input=78aa5d576683bb4b]*/
    1531  
    1532  /*[clinic input]
    1533  @classmethod
    1534  code.__new__ as code_new
    1535  
    1536      argcount: int
    1537      posonlyargcount: int
    1538      kwonlyargcount: int
    1539      nlocals: int
    1540      stacksize: int
    1541      flags: int
    1542      codestring as code: object(subclass_of="&PyBytes_Type")
    1543      constants as consts: object(subclass_of="&PyTuple_Type")
    1544      names: object(subclass_of="&PyTuple_Type")
    1545      varnames: object(subclass_of="&PyTuple_Type")
    1546      filename: unicode
    1547      name: unicode
    1548      qualname: unicode
    1549      firstlineno: int
    1550      linetable: object(subclass_of="&PyBytes_Type")
    1551      exceptiontable: object(subclass_of="&PyBytes_Type")
    1552      freevars: object(subclass_of="&PyTuple_Type", c_default="NULL") = ()
    1553      cellvars: object(subclass_of="&PyTuple_Type", c_default="NULL") = ()
    1554      /
    1555  
    1556  Create a code object.  Not for the faint of heart.
    1557  [clinic start generated code]*/
    1558  
    1559  static PyObject *
    1560  code_new_impl(PyTypeObject *type, int argcount, int posonlyargcount,
    1561                int kwonlyargcount, int nlocals, int stacksize, int flags,
    1562                PyObject *code, PyObject *consts, PyObject *names,
    1563                PyObject *varnames, PyObject *filename, PyObject *name,
    1564                PyObject *qualname, int firstlineno, PyObject *linetable,
    1565                PyObject *exceptiontable, PyObject *freevars,
    1566                PyObject *cellvars)
    1567  /*[clinic end generated code: output=069fa20d299f9dda input=e31da3c41ad8064a]*/
    1568  {
    1569      PyObject *co = NULL;
    1570      PyObject *ournames = NULL;
    1571      PyObject *ourvarnames = NULL;
    1572      PyObject *ourfreevars = NULL;
    1573      PyObject *ourcellvars = NULL;
    1574  
    1575      if (PySys_Audit("code.__new__", "OOOiiiiii",
    1576                      code, filename, name, argcount, posonlyargcount,
    1577                      kwonlyargcount, nlocals, stacksize, flags) < 0) {
    1578          goto cleanup;
    1579      }
    1580  
    1581      if (argcount < 0) {
    1582          PyErr_SetString(
    1583              PyExc_ValueError,
    1584              "code: argcount must not be negative");
    1585          goto cleanup;
    1586      }
    1587  
    1588      if (posonlyargcount < 0) {
    1589          PyErr_SetString(
    1590              PyExc_ValueError,
    1591              "code: posonlyargcount must not be negative");
    1592          goto cleanup;
    1593      }
    1594  
    1595      if (kwonlyargcount < 0) {
    1596          PyErr_SetString(
    1597              PyExc_ValueError,
    1598              "code: kwonlyargcount must not be negative");
    1599          goto cleanup;
    1600      }
    1601      if (nlocals < 0) {
    1602          PyErr_SetString(
    1603              PyExc_ValueError,
    1604              "code: nlocals must not be negative");
    1605          goto cleanup;
    1606      }
    1607  
    1608      ournames = validate_and_copy_tuple(names);
    1609      if (ournames == NULL)
    1610          goto cleanup;
    1611      ourvarnames = validate_and_copy_tuple(varnames);
    1612      if (ourvarnames == NULL)
    1613          goto cleanup;
    1614      if (freevars)
    1615          ourfreevars = validate_and_copy_tuple(freevars);
    1616      else
    1617          ourfreevars = PyTuple_New(0);
    1618      if (ourfreevars == NULL)
    1619          goto cleanup;
    1620      if (cellvars)
    1621          ourcellvars = validate_and_copy_tuple(cellvars);
    1622      else
    1623          ourcellvars = PyTuple_New(0);
    1624      if (ourcellvars == NULL)
    1625          goto cleanup;
    1626  
    1627      co = (PyObject *)PyCode_NewWithPosOnlyArgs(argcount, posonlyargcount,
    1628                                                 kwonlyargcount,
    1629                                                 nlocals, stacksize, flags,
    1630                                                 code, consts, ournames,
    1631                                                 ourvarnames, ourfreevars,
    1632                                                 ourcellvars, filename,
    1633                                                 name, qualname, firstlineno,
    1634                                                 linetable,
    1635                                                 exceptiontable
    1636                                                );
    1637    cleanup:
    1638      Py_XDECREF(ournames);
    1639      Py_XDECREF(ourvarnames);
    1640      Py_XDECREF(ourfreevars);
    1641      Py_XDECREF(ourcellvars);
    1642      return co;
    1643  }
    1644  
    1645  static void
    1646  free_monitoring_data(_PyCoMonitoringData *data)
    1647  {
    1648      if (data == NULL) {
    1649          return;
    1650      }
    1651      if (data->tools) {
    1652          PyMem_Free(data->tools);
    1653      }
    1654      if (data->lines) {
    1655          PyMem_Free(data->lines);
    1656      }
    1657      if (data->line_tools) {
    1658          PyMem_Free(data->line_tools);
    1659      }
    1660      if (data->per_instruction_opcodes) {
    1661          PyMem_Free(data->per_instruction_opcodes);
    1662      }
    1663      if (data->per_instruction_tools) {
    1664          PyMem_Free(data->per_instruction_tools);
    1665      }
    1666      PyMem_Free(data);
    1667  }
    1668  
    1669  static void
    1670  code_dealloc(PyCodeObject *co)
    1671  {
    1672      assert(Py_REFCNT(co) == 0);
    1673      Py_SET_REFCNT(co, 1);
    1674      notify_code_watchers(PY_CODE_EVENT_DESTROY, co);
    1675      if (Py_REFCNT(co) > 1) {
    1676          Py_SET_REFCNT(co, Py_REFCNT(co) - 1);
    1677          return;
    1678      }
    1679      Py_SET_REFCNT(co, 0);
    1680  
    1681      if (co->co_extra != NULL) {
    1682          PyInterpreterState *interp = _PyInterpreterState_GET();
    1683          _PyCodeObjectExtra *co_extra = co->co_extra;
    1684  
    1685          for (Py_ssize_t i = 0; i < co_extra->ce_size; i++) {
    1686              freefunc free_extra = interp->co_extra_freefuncs[i];
    1687  
    1688              if (free_extra != NULL) {
    1689                  free_extra(co_extra->ce_extras[i]);
    1690              }
    1691          }
    1692  
    1693          PyMem_Free(co_extra);
    1694      }
    1695  
    1696      Py_XDECREF(co->co_consts);
    1697      Py_XDECREF(co->co_names);
    1698      Py_XDECREF(co->co_localsplusnames);
    1699      Py_XDECREF(co->co_localspluskinds);
    1700      Py_XDECREF(co->co_filename);
    1701      Py_XDECREF(co->co_name);
    1702      Py_XDECREF(co->co_qualname);
    1703      Py_XDECREF(co->co_linetable);
    1704      Py_XDECREF(co->co_exceptiontable);
    1705      if (co->_co_cached != NULL) {
    1706          Py_XDECREF(co->_co_cached->_co_code);
    1707          Py_XDECREF(co->_co_cached->_co_cellvars);
    1708          Py_XDECREF(co->_co_cached->_co_freevars);
    1709          Py_XDECREF(co->_co_cached->_co_varnames);
    1710          PyMem_Free(co->_co_cached);
    1711      }
    1712      if (co->co_weakreflist != NULL) {
    1713          PyObject_ClearWeakRefs((PyObject*)co);
    1714      }
    1715      free_monitoring_data(co->_co_monitoring);
    1716      PyObject_Free(co);
    1717  }
    1718  
    1719  static PyObject *
    1720  code_repr(PyCodeObject *co)
    1721  {
    1722      int lineno;
    1723      if (co->co_firstlineno != 0)
    1724          lineno = co->co_firstlineno;
    1725      else
    1726          lineno = -1;
    1727      if (co->co_filename && PyUnicode_Check(co->co_filename)) {
    1728          return PyUnicode_FromFormat(
    1729              "<code object %U at %p, file \"%U\", line %d>",
    1730              co->co_name, co, co->co_filename, lineno);
    1731      } else {
    1732          return PyUnicode_FromFormat(
    1733              "<code object %U at %p, file ???, line %d>",
    1734              co->co_name, co, lineno);
    1735      }
    1736  }
    1737  
    1738  static PyObject *
    1739  code_richcompare(PyObject *self, PyObject *other, int op)
    1740  {
    1741      PyCodeObject *co, *cp;
    1742      int eq;
    1743      PyObject *consts1, *consts2;
    1744      PyObject *res;
    1745  
    1746      if ((op != Py_EQ && op != Py_NE) ||
    1747          !PyCode_Check(self) ||
    1748          !PyCode_Check(other)) {
    1749          Py_RETURN_NOTIMPLEMENTED;
    1750      }
    1751  
    1752      co = (PyCodeObject *)self;
    1753      cp = (PyCodeObject *)other;
    1754  
    1755      eq = PyObject_RichCompareBool(co->co_name, cp->co_name, Py_EQ);
    1756      if (!eq) goto unequal;
    1757      eq = co->co_argcount == cp->co_argcount;
    1758      if (!eq) goto unequal;
    1759      eq = co->co_posonlyargcount == cp->co_posonlyargcount;
    1760      if (!eq) goto unequal;
    1761      eq = co->co_kwonlyargcount == cp->co_kwonlyargcount;
    1762      if (!eq) goto unequal;
    1763      eq = co->co_flags == cp->co_flags;
    1764      if (!eq) goto unequal;
    1765      eq = co->co_firstlineno == cp->co_firstlineno;
    1766      if (!eq) goto unequal;
    1767      eq = Py_SIZE(co) == Py_SIZE(cp);
    1768      if (!eq) {
    1769          goto unequal;
    1770      }
    1771      for (int i = 0; i < Py_SIZE(co); i++) {
    1772          _Py_CODEUNIT co_instr = _PyCode_CODE(co)[i];
    1773          _Py_CODEUNIT cp_instr = _PyCode_CODE(cp)[i];
    1774          co_instr.op.code = _PyOpcode_Deopt[co_instr.op.code];
    1775          cp_instr.op.code = _PyOpcode_Deopt[cp_instr.op.code];
    1776          eq = co_instr.cache == cp_instr.cache;
    1777          if (!eq) {
    1778              goto unequal;
    1779          }
    1780          i += _PyOpcode_Caches[co_instr.op.code];
    1781      }
    1782  
    1783      /* compare constants */
    1784      consts1 = _PyCode_ConstantKey(co->co_consts);
    1785      if (!consts1)
    1786          return NULL;
    1787      consts2 = _PyCode_ConstantKey(cp->co_consts);
    1788      if (!consts2) {
    1789          Py_DECREF(consts1);
    1790          return NULL;
    1791      }
    1792      eq = PyObject_RichCompareBool(consts1, consts2, Py_EQ);
    1793      Py_DECREF(consts1);
    1794      Py_DECREF(consts2);
    1795      if (eq <= 0) goto unequal;
    1796  
    1797      eq = PyObject_RichCompareBool(co->co_names, cp->co_names, Py_EQ);
    1798      if (eq <= 0) goto unequal;
    1799      eq = PyObject_RichCompareBool(co->co_localsplusnames,
    1800                                    cp->co_localsplusnames, Py_EQ);
    1801      if (eq <= 0) goto unequal;
    1802      eq = PyObject_RichCompareBool(co->co_linetable, cp->co_linetable, Py_EQ);
    1803      if (eq <= 0) {
    1804          goto unequal;
    1805      }
    1806      eq = PyObject_RichCompareBool(co->co_exceptiontable,
    1807                                    cp->co_exceptiontable, Py_EQ);
    1808      if (eq <= 0) {
    1809          goto unequal;
    1810      }
    1811  
    1812      if (op == Py_EQ)
    1813          res = Py_True;
    1814      else
    1815          res = Py_False;
    1816      goto done;
    1817  
    1818    unequal:
    1819      if (eq < 0)
    1820          return NULL;
    1821      if (op == Py_NE)
    1822          res = Py_True;
    1823      else
    1824          res = Py_False;
    1825  
    1826    done:
    1827      return Py_NewRef(res);
    1828  }
    1829  
    1830  static Py_hash_t
    1831  code_hash(PyCodeObject *co)
    1832  {
    1833      Py_uhash_t uhash = 20221211;
    1834      #define SCRAMBLE_IN(H) do {       \
    1835          uhash ^= (Py_uhash_t)(H);     \
    1836          uhash *= _PyHASH_MULTIPLIER;  \
    1837      } while (0)
    1838      #define SCRAMBLE_IN_HASH(EXPR) do {     \
    1839          Py_hash_t h = PyObject_Hash(EXPR);  \
    1840          if (h == -1) {                      \
    1841              return -1;                      \
    1842          }                                   \
    1843          SCRAMBLE_IN(h);                     \
    1844      } while (0)
    1845  
    1846      SCRAMBLE_IN_HASH(co->co_name);
    1847      SCRAMBLE_IN_HASH(co->co_consts);
    1848      SCRAMBLE_IN_HASH(co->co_names);
    1849      SCRAMBLE_IN_HASH(co->co_localsplusnames);
    1850      SCRAMBLE_IN_HASH(co->co_linetable);
    1851      SCRAMBLE_IN_HASH(co->co_exceptiontable);
    1852      SCRAMBLE_IN(co->co_argcount);
    1853      SCRAMBLE_IN(co->co_posonlyargcount);
    1854      SCRAMBLE_IN(co->co_kwonlyargcount);
    1855      SCRAMBLE_IN(co->co_flags);
    1856      SCRAMBLE_IN(co->co_firstlineno);
    1857      SCRAMBLE_IN(Py_SIZE(co));
    1858      for (int i = 0; i < Py_SIZE(co); i++) {
    1859          int deop = _Py_GetBaseOpcode(co, i);
    1860          SCRAMBLE_IN(deop);
    1861          SCRAMBLE_IN(_PyCode_CODE(co)[i].op.arg);
    1862          i += _PyOpcode_Caches[deop];
    1863      }
    1864      if ((Py_hash_t)uhash == -1) {
    1865          return -2;
    1866      }
    1867      return (Py_hash_t)uhash;
    1868  }
    1869  
    1870  
    1871  #define OFF(x) offsetof(PyCodeObject, x)
    1872  
    1873  static PyMemberDef code_memberlist[] = {
    1874      {"co_argcount",        T_INT,    OFF(co_argcount),        READONLY},
    1875      {"co_posonlyargcount", T_INT,    OFF(co_posonlyargcount), READONLY},
    1876      {"co_kwonlyargcount",  T_INT,    OFF(co_kwonlyargcount),  READONLY},
    1877      {"co_stacksize",       T_INT,    OFF(co_stacksize),       READONLY},
    1878      {"co_flags",           T_INT,    OFF(co_flags),           READONLY},
    1879      {"co_nlocals",         T_INT,    OFF(co_nlocals),         READONLY},
    1880      {"co_consts",          T_OBJECT, OFF(co_consts),          READONLY},
    1881      {"co_names",           T_OBJECT, OFF(co_names),           READONLY},
    1882      {"co_filename",        T_OBJECT, OFF(co_filename),        READONLY},
    1883      {"co_name",            T_OBJECT, OFF(co_name),            READONLY},
    1884      {"co_qualname",        T_OBJECT, OFF(co_qualname),        READONLY},
    1885      {"co_firstlineno",     T_INT,    OFF(co_firstlineno),     READONLY},
    1886      {"co_linetable",       T_OBJECT, OFF(co_linetable),       READONLY},
    1887      {"co_exceptiontable",  T_OBJECT, OFF(co_exceptiontable),  READONLY},
    1888      {NULL}      /* Sentinel */
    1889  };
    1890  
    1891  
    1892  static PyObject *
    1893  code_getlnotab(PyCodeObject *code, void *closure)
    1894  {
    1895      if (PyErr_WarnEx(PyExc_DeprecationWarning,
    1896                       "co_lnotab is deprecated, use co_lines instead.",
    1897                       1) < 0) {
    1898          return NULL;
    1899      }
    1900      return decode_linetable(code);
    1901  }
    1902  
    1903  static PyObject *
    1904  code_getvarnames(PyCodeObject *code, void *closure)
    1905  {
    1906      return _PyCode_GetVarnames(code);
    1907  }
    1908  
    1909  static PyObject *
    1910  code_getcellvars(PyCodeObject *code, void *closure)
    1911  {
    1912      return _PyCode_GetCellvars(code);
    1913  }
    1914  
    1915  static PyObject *
    1916  code_getfreevars(PyCodeObject *code, void *closure)
    1917  {
    1918      return _PyCode_GetFreevars(code);
    1919  }
    1920  
    1921  static PyObject *
    1922  code_getcodeadaptive(PyCodeObject *code, void *closure)
    1923  {
    1924      return PyBytes_FromStringAndSize(code->co_code_adaptive,
    1925                                       _PyCode_NBYTES(code));
    1926  }
    1927  
    1928  static PyObject *
    1929  code_getcode(PyCodeObject *code, void *closure)
    1930  {
    1931      return _PyCode_GetCode(code);
    1932  }
    1933  
    1934  static PyGetSetDef code_getsetlist[] = {
    1935      {"co_lnotab",         (getter)code_getlnotab,       NULL, NULL},
    1936      {"_co_code_adaptive", (getter)code_getcodeadaptive, NULL, NULL},
    1937      // The following old names are kept for backward compatibility.
    1938      {"co_varnames",       (getter)code_getvarnames,     NULL, NULL},
    1939      {"co_cellvars",       (getter)code_getcellvars,     NULL, NULL},
    1940      {"co_freevars",       (getter)code_getfreevars,     NULL, NULL},
    1941      {"co_code",           (getter)code_getcode,         NULL, NULL},
    1942      {0}
    1943  };
    1944  
    1945  
    1946  static PyObject *
    1947  code_sizeof(PyCodeObject *co, PyObject *Py_UNUSED(args))
    1948  {
    1949      size_t res = _PyObject_VAR_SIZE(Py_TYPE(co), Py_SIZE(co));
    1950      _PyCodeObjectExtra *co_extra = (_PyCodeObjectExtra*) co->co_extra;
    1951      if (co_extra != NULL) {
    1952          res += sizeof(_PyCodeObjectExtra);
    1953          res += ((size_t)co_extra->ce_size - 1) * sizeof(co_extra->ce_extras[0]);
    1954      }
    1955      return PyLong_FromSize_t(res);
    1956  }
    1957  
    1958  static PyObject *
    1959  code_linesiterator(PyCodeObject *code, PyObject *Py_UNUSED(args))
    1960  {
    1961      return (PyObject *)new_linesiterator(code);
    1962  }
    1963  
    1964  /*[clinic input]
    1965  @text_signature "($self, /, **changes)"
    1966  code.replace
    1967  
    1968      *
    1969      co_argcount: int(c_default="self->co_argcount") = unchanged
    1970      co_posonlyargcount: int(c_default="self->co_posonlyargcount") = unchanged
    1971      co_kwonlyargcount: int(c_default="self->co_kwonlyargcount") = unchanged
    1972      co_nlocals: int(c_default="self->co_nlocals") = unchanged
    1973      co_stacksize: int(c_default="self->co_stacksize") = unchanged
    1974      co_flags: int(c_default="self->co_flags") = unchanged
    1975      co_firstlineno: int(c_default="self->co_firstlineno") = unchanged
    1976      co_code: object(subclass_of="&PyBytes_Type", c_default="NULL") = unchanged
    1977      co_consts: object(subclass_of="&PyTuple_Type", c_default="self->co_consts") = unchanged
    1978      co_names: object(subclass_of="&PyTuple_Type", c_default="self->co_names") = unchanged
    1979      co_varnames: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
    1980      co_freevars: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
    1981      co_cellvars: object(subclass_of="&PyTuple_Type", c_default="NULL") = unchanged
    1982      co_filename: unicode(c_default="self->co_filename") = unchanged
    1983      co_name: unicode(c_default="self->co_name") = unchanged
    1984      co_qualname: unicode(c_default="self->co_qualname") = unchanged
    1985      co_linetable: object(subclass_of="&PyBytes_Type", c_default="self->co_linetable") = unchanged
    1986      co_exceptiontable: object(subclass_of="&PyBytes_Type", c_default="self->co_exceptiontable") = unchanged
    1987  
    1988  Return a copy of the code object with new values for the specified fields.
    1989  [clinic start generated code]*/
    1990  
    1991  static PyObject *
    1992  code_replace_impl(PyCodeObject *self, int co_argcount,
    1993                    int co_posonlyargcount, int co_kwonlyargcount,
    1994                    int co_nlocals, int co_stacksize, int co_flags,
    1995                    int co_firstlineno, PyObject *co_code, PyObject *co_consts,
    1996                    PyObject *co_names, PyObject *co_varnames,
    1997                    PyObject *co_freevars, PyObject *co_cellvars,
    1998                    PyObject *co_filename, PyObject *co_name,
    1999                    PyObject *co_qualname, PyObject *co_linetable,
    2000                    PyObject *co_exceptiontable)
    2001  /*[clinic end generated code: output=e75c48a15def18b9 input=18e280e07846c122]*/
    2002  {
    2003  #define CHECK_INT_ARG(ARG) \
    2004          if (ARG < 0) { \
    2005              PyErr_SetString(PyExc_ValueError, \
    2006                              #ARG " must be a positive integer"); \
    2007              return NULL; \
    2008          }
    2009  
    2010      CHECK_INT_ARG(co_argcount);
    2011      CHECK_INT_ARG(co_posonlyargcount);
    2012      CHECK_INT_ARG(co_kwonlyargcount);
    2013      CHECK_INT_ARG(co_nlocals);
    2014      CHECK_INT_ARG(co_stacksize);
    2015      CHECK_INT_ARG(co_flags);
    2016      CHECK_INT_ARG(co_firstlineno);
    2017  
    2018  #undef CHECK_INT_ARG
    2019  
    2020      PyObject *code = NULL;
    2021      if (co_code == NULL) {
    2022          code = _PyCode_GetCode(self);
    2023          if (code == NULL) {
    2024              return NULL;
    2025          }
    2026          co_code = code;
    2027      }
    2028  
    2029      if (PySys_Audit("code.__new__", "OOOiiiiii",
    2030                      co_code, co_filename, co_name, co_argcount,
    2031                      co_posonlyargcount, co_kwonlyargcount, co_nlocals,
    2032                      co_stacksize, co_flags) < 0) {
    2033          Py_XDECREF(code);
    2034          return NULL;
    2035      }
    2036  
    2037      PyCodeObject *co = NULL;
    2038      PyObject *varnames = NULL;
    2039      PyObject *cellvars = NULL;
    2040      PyObject *freevars = NULL;
    2041      if (co_varnames == NULL) {
    2042          varnames = get_localsplus_names(self, CO_FAST_LOCAL, self->co_nlocals);
    2043          if (varnames == NULL) {
    2044              goto error;
    2045          }
    2046          co_varnames = varnames;
    2047      }
    2048      if (co_cellvars == NULL) {
    2049          cellvars = get_localsplus_names(self, CO_FAST_CELL, self->co_ncellvars);
    2050          if (cellvars == NULL) {
    2051              goto error;
    2052          }
    2053          co_cellvars = cellvars;
    2054      }
    2055      if (co_freevars == NULL) {
    2056          freevars = get_localsplus_names(self, CO_FAST_FREE, self->co_nfreevars);
    2057          if (freevars == NULL) {
    2058              goto error;
    2059          }
    2060          co_freevars = freevars;
    2061      }
    2062  
    2063      co = PyCode_NewWithPosOnlyArgs(
    2064          co_argcount, co_posonlyargcount, co_kwonlyargcount, co_nlocals,
    2065          co_stacksize, co_flags, co_code, co_consts, co_names,
    2066          co_varnames, co_freevars, co_cellvars, co_filename, co_name,
    2067          co_qualname, co_firstlineno,
    2068          co_linetable, co_exceptiontable);
    2069  
    2070  error:
    2071      Py_XDECREF(code);
    2072      Py_XDECREF(varnames);
    2073      Py_XDECREF(cellvars);
    2074      Py_XDECREF(freevars);
    2075      return (PyObject *)co;
    2076  }
    2077  
    2078  /*[clinic input]
    2079  code._varname_from_oparg
    2080  
    2081      oparg: int
    2082  
    2083  (internal-only) Return the local variable name for the given oparg.
    2084  
    2085  WARNING: this method is for internal use only and may change or go away.
    2086  [clinic start generated code]*/
    2087  
    2088  static PyObject *
    2089  code__varname_from_oparg_impl(PyCodeObject *self, int oparg)
    2090  /*[clinic end generated code: output=1fd1130413184206 input=c5fa3ee9bac7d4ca]*/
    2091  {
    2092      PyObject *name = PyTuple_GetItem(self->co_localsplusnames, oparg);
    2093      if (name == NULL) {
    2094          return NULL;
    2095      }
    2096      return Py_NewRef(name);
    2097  }
    2098  
    2099  /* XXX code objects need to participate in GC? */
    2100  
    2101  static struct PyMethodDef code_methods[] = {
    2102      {"__sizeof__", (PyCFunction)code_sizeof, METH_NOARGS},
    2103      {"co_lines", (PyCFunction)code_linesiterator, METH_NOARGS},
    2104      {"co_positions", (PyCFunction)code_positionsiterator, METH_NOARGS},
    2105      CODE_REPLACE_METHODDEF
    2106      CODE__VARNAME_FROM_OPARG_METHODDEF
    2107      {NULL, NULL}                /* sentinel */
    2108  };
    2109  
    2110  
    2111  PyTypeObject PyCode_Type = {
    2112      PyVarObject_HEAD_INIT(&PyType_Type, 0)
    2113      "code",
    2114      offsetof(PyCodeObject, co_code_adaptive),
    2115      sizeof(_Py_CODEUNIT),
    2116      (destructor)code_dealloc,           /* tp_dealloc */
    2117      0,                                  /* tp_vectorcall_offset */
    2118      0,                                  /* tp_getattr */
    2119      0,                                  /* tp_setattr */
    2120      0,                                  /* tp_as_async */
    2121      (reprfunc)code_repr,                /* tp_repr */
    2122      0,                                  /* tp_as_number */
    2123      0,                                  /* tp_as_sequence */
    2124      0,                                  /* tp_as_mapping */
    2125      (hashfunc)code_hash,                /* tp_hash */
    2126      0,                                  /* tp_call */
    2127      0,                                  /* tp_str */
    2128      PyObject_GenericGetAttr,            /* tp_getattro */
    2129      0,                                  /* tp_setattro */
    2130      0,                                  /* tp_as_buffer */
    2131      Py_TPFLAGS_DEFAULT,                 /* tp_flags */
    2132      code_new__doc__,                    /* tp_doc */
    2133      0,                                  /* tp_traverse */
    2134      0,                                  /* tp_clear */
    2135      code_richcompare,                   /* tp_richcompare */
    2136      offsetof(PyCodeObject, co_weakreflist),     /* tp_weaklistoffset */
    2137      0,                                  /* tp_iter */
    2138      0,                                  /* tp_iternext */
    2139      code_methods,                       /* tp_methods */
    2140      code_memberlist,                    /* tp_members */
    2141      code_getsetlist,                    /* tp_getset */
    2142      0,                                  /* tp_base */
    2143      0,                                  /* tp_dict */
    2144      0,                                  /* tp_descr_get */
    2145      0,                                  /* tp_descr_set */
    2146      0,                                  /* tp_dictoffset */
    2147      0,                                  /* tp_init */
    2148      0,                                  /* tp_alloc */
    2149      code_new,                           /* tp_new */
    2150  };
    2151  
    2152  
    2153  /******************
    2154   * other API
    2155   ******************/
    2156  
    2157  PyObject*
    2158  _PyCode_ConstantKey(PyObject *op)
    2159  {
    2160      PyObject *key;
    2161  
    2162      /* Py_None and Py_Ellipsis are singletons. */
    2163      if (op == Py_None || op == Py_Ellipsis
    2164         || PyLong_CheckExact(op)
    2165         || PyUnicode_CheckExact(op)
    2166            /* code_richcompare() uses _PyCode_ConstantKey() internally */
    2167         || PyCode_Check(op))
    2168      {
    2169          /* Objects of these types are always different from object of other
    2170           * type and from tuples. */
    2171          key = Py_NewRef(op);
    2172      }
    2173      else if (PyBool_Check(op) || PyBytes_CheckExact(op)) {
    2174          /* Make booleans different from integers 0 and 1.
    2175           * Avoid BytesWarning from comparing bytes with strings. */
    2176          key = PyTuple_Pack(2, Py_TYPE(op), op);
    2177      }
    2178      else if (PyFloat_CheckExact(op)) {
    2179          double d = PyFloat_AS_DOUBLE(op);
    2180          /* all we need is to make the tuple different in either the 0.0
    2181           * or -0.0 case from all others, just to avoid the "coercion".
    2182           */
    2183          if (d == 0.0 && copysign(1.0, d) < 0.0)
    2184              key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
    2185          else
    2186              key = PyTuple_Pack(2, Py_TYPE(op), op);
    2187      }
    2188      else if (PyComplex_CheckExact(op)) {
    2189          Py_complex z;
    2190          int real_negzero, imag_negzero;
    2191          /* For the complex case we must make complex(x, 0.)
    2192             different from complex(x, -0.) and complex(0., y)
    2193             different from complex(-0., y), for any x and y.
    2194             All four complex zeros must be distinguished.*/
    2195          z = PyComplex_AsCComplex(op);
    2196          real_negzero = z.real == 0.0 && copysign(1.0, z.real) < 0.0;
    2197          imag_negzero = z.imag == 0.0 && copysign(1.0, z.imag) < 0.0;
    2198          /* use True, False and None singleton as tags for the real and imag
    2199           * sign, to make tuples different */
    2200          if (real_negzero && imag_negzero) {
    2201              key = PyTuple_Pack(3, Py_TYPE(op), op, Py_True);
    2202          }
    2203          else if (imag_negzero) {
    2204              key = PyTuple_Pack(3, Py_TYPE(op), op, Py_False);
    2205          }
    2206          else if (real_negzero) {
    2207              key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
    2208          }
    2209          else {
    2210              key = PyTuple_Pack(2, Py_TYPE(op), op);
    2211          }
    2212      }
    2213      else if (PyTuple_CheckExact(op)) {
    2214          Py_ssize_t i, len;
    2215          PyObject *tuple;
    2216  
    2217          len = PyTuple_GET_SIZE(op);
    2218          tuple = PyTuple_New(len);
    2219          if (tuple == NULL)
    2220              return NULL;
    2221  
    2222          for (i=0; i < len; i++) {
    2223              PyObject *item, *item_key;
    2224  
    2225              item = PyTuple_GET_ITEM(op, i);
    2226              item_key = _PyCode_ConstantKey(item);
    2227              if (item_key == NULL) {
    2228                  Py_DECREF(tuple);
    2229                  return NULL;
    2230              }
    2231  
    2232              PyTuple_SET_ITEM(tuple, i, item_key);
    2233          }
    2234  
    2235          key = PyTuple_Pack(2, tuple, op);
    2236          Py_DECREF(tuple);
    2237      }
    2238      else if (PyFrozenSet_CheckExact(op)) {
    2239          Py_ssize_t pos = 0;
    2240          PyObject *item;
    2241          Py_hash_t hash;
    2242          Py_ssize_t i, len;
    2243          PyObject *tuple, *set;
    2244  
    2245          len = PySet_GET_SIZE(op);
    2246          tuple = PyTuple_New(len);
    2247          if (tuple == NULL)
    2248              return NULL;
    2249  
    2250          i = 0;
    2251          while (_PySet_NextEntry(op, &pos, &item, &hash)) {
    2252              PyObject *item_key;
    2253  
    2254              item_key = _PyCode_ConstantKey(item);
    2255              if (item_key == NULL) {
    2256                  Py_DECREF(tuple);
    2257                  return NULL;
    2258              }
    2259  
    2260              assert(i < len);
    2261              PyTuple_SET_ITEM(tuple, i, item_key);
    2262              i++;
    2263          }
    2264          set = PyFrozenSet_New(tuple);
    2265          Py_DECREF(tuple);
    2266          if (set == NULL)
    2267              return NULL;
    2268  
    2269          key = PyTuple_Pack(2, set, op);
    2270          Py_DECREF(set);
    2271          return key;
    2272      }
    2273      else {
    2274          /* for other types, use the object identifier as a unique identifier
    2275           * to ensure that they are seen as unequal. */
    2276          PyObject *obj_id = PyLong_FromVoidPtr(op);
    2277          if (obj_id == NULL)
    2278              return NULL;
    2279  
    2280          key = PyTuple_Pack(2, obj_id, op);
    2281          Py_DECREF(obj_id);
    2282      }
    2283      return key;
    2284  }
    2285  
    2286  void
    2287  _PyStaticCode_Fini(PyCodeObject *co)
    2288  {
    2289      deopt_code(co, _PyCode_CODE(co));
    2290      PyMem_Free(co->co_extra);
    2291      if (co->_co_cached != NULL) {
    2292          Py_CLEAR(co->_co_cached->_co_code);
    2293          Py_CLEAR(co->_co_cached->_co_cellvars);
    2294          Py_CLEAR(co->_co_cached->_co_freevars);
    2295          Py_CLEAR(co->_co_cached->_co_varnames);
    2296          PyMem_Free(co->_co_cached);
    2297          co->_co_cached = NULL;
    2298      }
    2299      co->co_extra = NULL;
    2300      if (co->co_weakreflist != NULL) {
    2301          PyObject_ClearWeakRefs((PyObject *)co);
    2302          co->co_weakreflist = NULL;
    2303      }
    2304      free_monitoring_data(co->_co_monitoring);
    2305      co->_co_monitoring = NULL;
    2306  }
    2307  
    2308  int
    2309  _PyStaticCode_Init(PyCodeObject *co)
    2310  {
    2311      int res = intern_strings(co->co_names);
    2312      if (res < 0) {
    2313          return -1;
    2314      }
    2315      res = intern_string_constants(co->co_consts, NULL);
    2316      if (res < 0) {
    2317          return -1;
    2318      }
    2319      res = intern_strings(co->co_localsplusnames);
    2320      if (res < 0) {
    2321          return -1;
    2322      }
    2323      _PyCode_Quicken(co);
    2324      return 0;
    2325  }
    2326  
    2327  #define MAX_CODE_UNITS_PER_LOC_ENTRY 8
    2328  
    2329  PyCodeObject *
    2330  _Py_MakeShimCode(const _PyShimCodeDef *codedef)
    2331  {
    2332      PyObject *name = NULL;
    2333      PyObject *co_code = NULL;
    2334      PyObject *lines = NULL;
    2335      PyCodeObject *codeobj = NULL;
    2336      uint8_t *loc_table = NULL;
    2337  
    2338      name = _PyUnicode_FromASCII(codedef->cname, strlen(codedef->cname));
    2339      if (name == NULL) {
    2340          goto cleanup;
    2341      }
    2342      co_code = PyBytes_FromStringAndSize(
    2343          (const char *)codedef->code, codedef->codelen);
    2344      if (co_code == NULL) {
    2345          goto cleanup;
    2346      }
    2347      int code_units = codedef->codelen / sizeof(_Py_CODEUNIT);
    2348      int loc_entries = (code_units + MAX_CODE_UNITS_PER_LOC_ENTRY - 1) /
    2349                        MAX_CODE_UNITS_PER_LOC_ENTRY;
    2350      loc_table = PyMem_Malloc(loc_entries);
    2351      if (loc_table == NULL) {
    2352          PyErr_NoMemory();
    2353          goto cleanup;
    2354      }
    2355      for (int i = 0; i < loc_entries-1; i++) {
    2356           loc_table[i] = 0x80 | (PY_CODE_LOCATION_INFO_NONE << 3) | 7;
    2357           code_units -= MAX_CODE_UNITS_PER_LOC_ENTRY;
    2358      }
    2359      assert(loc_entries > 0);
    2360      assert(code_units > 0 && code_units <= MAX_CODE_UNITS_PER_LOC_ENTRY);
    2361      loc_table[loc_entries-1] = 0x80 |
    2362          (PY_CODE_LOCATION_INFO_NONE << 3) | (code_units-1);
    2363      lines = PyBytes_FromStringAndSize((const char *)loc_table, loc_entries);
    2364      PyMem_Free(loc_table);
    2365      if (lines == NULL) {
    2366          goto cleanup;
    2367      }
    2368      _Py_DECLARE_STR(shim_name, "<shim>");
    2369      struct _PyCodeConstructor con = {
    2370          .filename = &_Py_STR(shim_name),
    2371          .name = name,
    2372          .qualname = name,
    2373          .flags = CO_NEWLOCALS | CO_OPTIMIZED,
    2374  
    2375          .code = co_code,
    2376          .firstlineno = 1,
    2377          .linetable = lines,
    2378  
    2379          .consts = (PyObject *)&_Py_SINGLETON(tuple_empty),
    2380          .names = (PyObject *)&_Py_SINGLETON(tuple_empty),
    2381  
    2382          .localsplusnames = (PyObject *)&_Py_SINGLETON(tuple_empty),
    2383          .localspluskinds = (PyObject *)&_Py_SINGLETON(bytes_empty),
    2384  
    2385          .argcount = 0,
    2386          .posonlyargcount = 0,
    2387          .kwonlyargcount = 0,
    2388  
    2389          .stacksize = codedef->stacksize,
    2390  
    2391          .exceptiontable = (PyObject *)&_Py_SINGLETON(bytes_empty),
    2392      };
    2393  
    2394      codeobj = _PyCode_New(&con);
    2395  cleanup:
    2396      Py_XDECREF(name);
    2397      Py_XDECREF(co_code);
    2398      Py_XDECREF(lines);
    2399      return codeobj;
    2400  }