bpo-43693: Add _PyCode_New(). (gh-26375)

This is an internal-only API that helps us manage the many values used to create a code object.

https://bugs.python.org/issue43693

Author: ericsnowcurrently

Include/cpython/code.h

@@ -64,7 +64,7 @@ struct PyCodeObject {
 
     /* These fields are set with computed values on new code objects. */
 
-    Py_ssize_t *co_cell2arg;    /* Maps cell vars which are arguments. */
+    int *co_cell2arg;           /* Maps cell vars which are arguments. */
     // These are redundant but offer some performance benefit.
     int co_nlocalsplus;         /* number of local + cell + free variables */
     int co_nlocals;             /* number of local variables */

Include/internal/pycore_code.h

@@ -3,7 +3,8 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
- 
+
+
 typedef struct {
     PyObject *ptr;  /* Cached pointer (borrowed reference) */
     uint64_t globals_ver;  /* ma_version of global dict */
@@ -24,7 +25,54 @@ struct _PyOpcache {
     char optimized;
 };
 
+
+struct _PyCodeConstructor {
+    /* metadata */
+    PyObject *filename;
+    PyObject *name;
+    int flags;
+
+    /* the code */
+    PyObject *code;
+    int firstlineno;
+    PyObject *linetable;
+
+    /* used by the code */
+    PyObject *consts;
+    PyObject *names;
+
+    /* mapping frame offsets to information */
+    PyObject *varnames;
+    PyObject *cellvars;
+    PyObject *freevars;
+
+    /* args (within varnames) */
+    int argcount;
+    int posonlyargcount;
+    int kwonlyargcount;
+
+    /* needed to create the frame */
+    int stacksize;
+
+    /* used by the eval loop */
+    PyObject *exceptiontable;
+};
+
+// Using an "arguments struct" like this is helpful for maintainability
+// in a case such as this with many parameters.  It does bear a risk:
+// if the struct changes and callers are not updated properly then the
+// compiler will not catch problems (like a missing argument).  This can
+// cause hard-to-debug problems.  The risk is mitigated by the use of
+// check_code() in codeobject.c.  However, we may decide to switch
+// back to a regular function signature.  Regardless, this approach
+// wouldn't be appropriate if this weren't a strictly internal API.
+// (See the comments in https://github.com/python/cpython/pull/26258.)
+PyAPI_FUNC(int) _PyCode_Validate(struct _PyCodeConstructor *);
+PyAPI_FUNC(PyCodeObject *) _PyCode_New(struct _PyCodeConstructor *);
+
+
 /* Private API */
+
 int _PyCode_InitOpcache(PyCodeObject *co);
 
 

Lib/ctypes/test/test_values.py

@@ -80,9 +80,9 @@ class struct_frozen(Structure):
                 continue
             items.append((entry.name.decode("ascii"), entry.size))
 
-        expected = [("__hello__", 142),
-                    ("__phello__", -142),
-                    ("__phello__.spam", 142),
+        expected = [("__hello__", 138),
+                    ("__phello__", -138),
+                    ("__phello__.spam", 138),
                     ]
         self.assertEqual(items, expected, "PyImport_FrozenModules example "
             "in Doc/library/ctypes.rst may be out of date")

Lib/importlib/_bootstrap_external.py

@@ -354,6 +354,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.10b1 3439 (Add ROT_N)
 #     Python 3.11a1 3450 Use exception table for unwinding ("zero cost" exception handling)
 #     Python 3.11a1 3451 (Add CALL_METHOD_KW)
+#     Python 3.11a1 3452 (drop nlocals from marshaled code objects)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -363,7 +364,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3451).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3452).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'