Add version number to code object for better versioning of functions.

Author: markshannon

Include/cpython/code.h

@@ -88,6 +88,7 @@ typedef struct {
     int co_nplaincellvars;        /* number of non-arg cell variables */       \
     int co_ncellvars;             /* total number of cell variables */         \
     int co_nfreevars;             /* number of free variables */               \
+    uint32_t co_version;          /* version number */                         \
                                                                                \
     PyObject *co_localsplusnames; /* tuple mapping offsets to names */         \
     PyObject *co_localspluskinds; /* Bytes mapping to local kinds (one byte    \

Objects/codeobject.c

@@ -11,6 +11,7 @@
 #include "pycore_tuple.h"         // _PyTuple_ITEMS()
 #include "clinic/codeobject.c.h"
 
+extern uint32_t _Py_next_func_version;
 
 /******************
  * generic helpers
@@ -347,7 +348,10 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
     co->co_nplaincellvars = nplaincellvars;
     co->co_ncellvars = ncellvars;
     co->co_nfreevars = nfreevars;
-
+    co->co_version = _Py_next_func_version;
+    if (_Py_next_func_version != 0) {
+        _Py_next_func_version++;
+    }
     /* not set */
     co->co_weakreflist = NULL;
     co->co_extra = NULL;

Objects/funcobject.c

@@ -7,7 +7,7 @@
 #include "pycore_pyerrors.h"      // _PyErr_Occurred()
 #include "structmember.h"         // PyMemberDef
 
-static uint32_t next_func_version = 1;
+uint32_t _Py_next_func_version = 10000; /* Leave plenty of space for deep frozen code objects */
 
 PyFunctionObject *
 _PyFunction_FromConstructor(PyFrameConstructor *constr)
@@ -137,10 +137,10 @@ uint32_t _PyFunction_GetVersionForCurrentState(PyFunctionObject *func)
     if (func->vectorcall != _PyFunction_Vectorcall) {
         return 0;
     }
-    if (next_func_version == 0) {
+    if (_Py_next_func_version == 0) {
         return 0;
     }
-    uint32_t v = next_func_version++;
+    uint32_t v = _Py_next_func_version++;
     func->func_version = v;
     return v;
 }

Python/ceval.c

@@ -4814,6 +4814,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
                 assert(PyTuple_CheckExact(TOP()));
                 func->func_defaults = POP();
             }
+            func->func_version = ((PyCodeObject *)codeobj)->co_version;
 
             PUSH((PyObject *)func);
             DISPATCH();

Tools/build/deepfreeze.py

@@ -44,6 +44,7 @@ def make_string_literal(b: bytes) -> str:
 CO_FAST_CELL = 0x40
 CO_FAST_FREE = 0x80
 
+next_code_version = 1
 
 def get_localsplus(code: types.CodeType):
     a = collections.defaultdict(int)
@@ -228,6 +229,7 @@ def generate_unicode(self, name: str, s: str) -> str:
 
 
     def generate_code(self, name: str, code: types.CodeType) -> str:
+        global next_code_version
         # The ordering here matches PyCode_NewWithPosOnlyArgs()
         # (but see below).
         co_consts = self.generate(name + "_consts", code.co_consts)
@@ -270,6 +272,8 @@ def generate_code(self, name: str, code: types.CodeType) -> str:
             self.write(f".co_nplaincellvars = {nplaincellvars},")
             self.write(f".co_ncellvars = {ncellvars},")
             self.write(f".co_nfreevars = {nfreevars},")
+            self.write(f".co_version = {next_code_version},")
+            next_code_version += 1
             self.write(f".co_localsplusnames = {co_localsplusnames},")
             self.write(f".co_localspluskinds = {co_localspluskinds},")
             self.write(f".co_filename = {co_filename},")