python · markshannon · Nov 10, 2021 · Nov 10, 2021
diff --git a/Include/cpython/funcobject.h b/Include/cpython/funcobject.h
@@ -7,56 +7,7 @@
 extern "C" {
 #endif
 
-
-#define COMMON_FIELDS(PREFIX) \
-    PyObject *PREFIX ## globals; \
-    PyObject *PREFIX ## builtins; \
-    PyObject *PREFIX ## name; \
-    PyObject *PREFIX ## qualname; \
-    PyObject *PREFIX ## code;        /* A code object, the __code__ attribute */ \
-    PyObject *PREFIX ## defaults;    /* NULL or a tuple */ \
-    PyObject *PREFIX ## kwdefaults;  /* NULL or a dict */ \
-    PyObject *PREFIX ## closure;     /* NULL or a tuple of cell objects */
-
-typedef struct {
-    COMMON_FIELDS(fc_)
-} PyFrameConstructor;
-
-/* Function objects and code objects should not be confused with each other:
- *
- * Function objects are created by the execution of the 'def' statement.
- * They reference a code object in their __code__ attribute, which is a
- * purely syntactic object, i.e. nothing more than a compiled version of some
- * source code lines.  There is one code object per source code "fragment",
- * but each code object can be referenced by zero or many function objects
- * depending only on how many times the 'def' statement in the source was
- * executed so far.
- */
-
-typedef struct {
-    PyObject_HEAD
-    COMMON_FIELDS(func_)
-    PyObject *func_doc;         /* The __doc__ attribute, can be anything */
-    PyObject *func_dict;        /* The __dict__ attribute, a dict or NULL */
-    PyObject *func_weakreflist; /* List of weak references */
-    PyObject *func_module;      /* The __module__ attribute, can be anything */
-    PyObject *func_annotations; /* Annotations, a dict or NULL */
-    vectorcallfunc vectorcall;
-    /* Version number for use by specializer.
-     * Can set to non-zero when we want to specialize.
-     * Will be set to zero if any of these change:
-     *     defaults
-     *     kwdefaults (only if the object changes, not the contents of the dict)
-     *     code
-     *     annotations */
-    uint32_t func_version;
-
-    /* Invariant:
-     *     func_closure contains the bindings for func_code->co_freevars, so
-     *     PyTuple_Size(func_closure) == PyCode_GetNumFree(func_code)
-     *     (func_closure may be NULL if PyCode_GetNumFree(func_code) == 0).
-     */
-} PyFunctionObject;
+typedef struct _functionobject PyFunctionObject;
 
 PyAPI_DATA(PyTypeObject) PyFunction_Type;
 
@@ -82,27 +33,14 @@ PyAPI_FUNC(PyObject *) _PyFunction_Vectorcall(
     size_t nargsf,
     PyObject *kwnames);
 
-uint32_t _PyFunction_GetVersionForCurrentState(PyFunctionObject *func);
-
-/* Macros for direct access to these values. Type checks are *not*
-   done, so use with care. */
-#define PyFunction_GET_CODE(func) \
-        (((PyFunctionObject *)func) -> func_code)
-#define PyFunction_GET_GLOBALS(func) \
-        (((PyFunctionObject *)func) -> func_globals)
-#define PyFunction_GET_MODULE(func) \
-        (((PyFunctionObject *)func) -> func_module)
-#define PyFunction_GET_DEFAULTS(func) \
-        (((PyFunctionObject *)func) -> func_defaults)
-#define PyFunction_GET_KW_DEFAULTS(func) \
-        (((PyFunctionObject *)func) -> func_kwdefaults)
-#define PyFunction_GET_CLOSURE(func) \
-        (((PyFunctionObject *)func) -> func_closure)
-#define PyFunction_GET_ANNOTATIONS(func) \
-        (((PyFunctionObject *)func) -> func_annotations)
-
-#define PyFunction_AS_FRAME_CONSTRUCTOR(func) \
-        ((PyFrameConstructor *)&((PyFunctionObject *)(func))->func_globals)
+/* Macros for backwards compatibility. */
+#define PyFunction_GET_CODE(func) PyFunction_GetCode(func)
+#define PyFunction_GET_GLOBALS(func) PyFunction_GetGlobals(func)
+#define PyFunction_GET_MODULE(func) PyFunction_GetModule(func)
+#define PyFunction_GET_DEFAULTS(func) PyFunction_GetDefaults(func)
+#define PyFunction_GET_KW_DEFAULTS(func) PyFunction_GetKwDefaults(func)
+#define PyFunction_GET_CLOSURE(func) PyFunction_GetClosure(func)
+#define PyFunction_GET_ANNOTATIONS(func) PyFunction_GetAnnotations(func)
 
 /* The classmethod and staticmethod types lives here, too */
 PyAPI_DATA(PyTypeObject) PyClassMethod_Type;

diff --git a/Include/internal/pycore_ceval.h b/Include/internal/pycore_ceval.h
@@ -12,6 +12,7 @@ extern "C" {
 struct pyruntimestate;
 struct _ceval_runtime_state;
 
+#include "pycore_function.h"      // PyFrameConstructor
 #include "pycore_interp.h"        // PyInterpreterState.eval_frame
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 

diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
@@ -4,6 +4,8 @@
 extern "C" {
 #endif
 
+#include "pycore_function.h"      // PyFrameConstructor
+
 /* These values are chosen so that the inline functions below all
  * compare f_state to zero.
  */

diff --git a/Include/internal/pycore_function.h b/Include/internal/pycore_function.h
@@ -0,0 +1,63 @@
+#ifndef PYCORE_FUNCTION_H
+#define PYCORE_FUNCTION_H
+
+#define COMMON_FIELDS(PREFIX) \
+    PyObject *PREFIX ## globals; \
+    PyObject *PREFIX ## builtins; \
+    PyObject *PREFIX ## name; \
+    PyObject *PREFIX ## qualname; \
+    PyObject *PREFIX ## code;        /* A code object, the __code__ attribute */ \
+    PyObject *PREFIX ## defaults;    /* NULL or a tuple */ \
+    PyObject *PREFIX ## kwdefaults;  /* NULL or a dict */ \
+    PyObject *PREFIX ## closure;     /* NULL or a tuple of cell objects */
+
+typedef struct {
+    COMMON_FIELDS(fc_)
+} PyFrameConstructor;
+
+/* Function objects and code objects should not be confused with each other:
+ *
+ * Function objects are created by the execution of the 'def' statement.
+ * They reference a code object in their __code__ attribute, which is a
+ * purely syntactic object, i.e. nothing more than a compiled version of some
+ * source code lines.  There is one code object per source code "fragment",
+ * but each code object can be referenced by zero or many function objects
+ * depending only on how many times the 'def' statement in the source was
+ * executed so far.
+ */
+
+typedef struct _functionobject {
+    PyObject_HEAD
+    COMMON_FIELDS(func_)
+    PyObject *func_doc;         /* The __doc__ attribute, can be anything */
+    PyObject *func_dict;        /* The __dict__ attribute, a dict or NULL */
+    PyObject *func_weakreflist; /* List of weak references */
+    PyObject *func_module;      /* The __module__ attribute, can be anything */
+    PyObject *func_annotations; /* Annotations, a dict or NULL */
+    vectorcallfunc vectorcall;
+    /* Version number for use by specializer.
+     * Can set to non-zero when we want to specialize.
+     * Will be set to zero if any of these change:
+     *     defaults
+     *     kwdefaults (only if the object changes, not the contents of the dict)
+     *     code
+     *     annotations */
+    uint32_t func_version;
+
+    /* Invariant:
+     *     func_closure contains the bindings for func_code->co_freevars, so
+     *     PyTuple_Size(func_closure) == PyCode_GetNumFree(func_code)
+     *     (func_closure may be NULL if PyCode_GetNumFree(func_code) == 0).
+     */
+} PyFunctionObject;
+
+#define PyFunction_AS_FRAME_CONSTRUCTOR(func) \
+        ((PyFrameConstructor *)&((PyFunctionObject *)(func))->func_globals)
+
+uint32_t _PyFunction_GetVersionForCurrentState(PyFunctionObject *func);
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif // PYCORE_FUNCTION_H
@@ -1256,6 +1256,8 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/internal/pycore_dtoa.h \
 		$(srcdir)/Include/internal/pycore_fileutils.h \
 		$(srcdir)/Include/internal/pycore_floatobject.h \
+		$(srcdir)/Include/internal/pycore_frame.h \
+		$(srcdir)/Include/internal/pycore_function.h \
 		$(srcdir)/Include/internal/pycore_format.h \
 		$(srcdir)/Include/internal/pycore_getopt.h \
 		$(srcdir)/Include/internal/pycore_gil.h \

diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-11-10-13-08-41.bpo-45753.WEDzYA.rst b/Misc/NEWS.d/next/Core and Builtins/2021-11-10-13-08-41.bpo-45753.WEDzYA.rst
@@ -0,0 +1,4 @@
+Move the PyFunctionObject struct to an internal header.
+
+The meaning to the internal fields of the function was never defined and
+could result in subtle bugs if misused. This move makes that clearer.
@@ -1,6 +1,7 @@
 #include "Python.h"
 #include "pycore_call.h"          // _PyObject_CallNoArgsTstate()
 #include "pycore_ceval.h"         // _PyEval_EvalFrame()
+#include "pycore_function.h"      // PyFrameConstructor
 #include "pycore_object.h"        // _PyObject_GC_TRACK()
 #include "pycore_pyerrors.h"      // _PyErr_Occurred()
 #include "pycore_pystate.h"       // _PyThreadState_GET()

@@ -192,6 +192,8 @@
     <ClInclude Include="..\Include\internal\pycore_dtoa.h" />
     <ClInclude Include="..\Include\internal\pycore_fileutils.h" />
     <ClInclude Include="..\Include\internal\pycore_floatobject.h" />
+    <ClInclude Include="..\Include\internal\pycore_frame.h" />
+    <ClInclude Include="..\Include\internal\pycore_function.h" />
     <ClInclude Include="..\Include\internal\pycore_format.h" />
     <ClInclude Include="..\Include\internal\pycore_gc.h" />
     <ClInclude Include="..\Include\internal\pycore_getopt.h" />

@@ -525,6 +525,12 @@
     <ClInclude Include="..\Include\internal\pycore_floatobject.h">
       <Filter>Include\internal</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_frame.h">
+      <Filter>Include\internal</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_function.h">
+      <Filter>Include\internal</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_format.h">
       <Filter>Include\internal</Filter>
     </ClInclude>

@@ -5,6 +5,7 @@
 #include "pycore_ast.h"           // _PyAST_Validate()
 #include "pycore_call.h"          // _PyObject_CallNoArgs()
 #include "pycore_compile.h"       // _PyAST_Compile()
+#include "pycore_function.h"      // PyFrameConstructor
 #include "pycore_object.h"        // _Py_AddToAllObjects()
 #include "pycore_pyerrors.h"      // _PyErr_NoMemory()
 #include "pycore_pystate.h"       // _PyThreadState_GET()

@@ -14,6 +14,7 @@
 #include "pycore_call.h"          // _PyObject_FastCallDictTstate()
 #include "pycore_ceval.h"         // _PyEval_SignalAsyncExc()
 #include "pycore_code.h"
+#include "pycore_function.h"
 #include "pycore_initconfig.h"    // _PyStatus_OK()
 #include "pycore_long.h"          // _PyLong_GetZero()
 #include "pycore_object.h"        // _PyObject_GC_TRACK()
@@ -4625,7 +4626,8 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
             }
             // Check if the call can be inlined or not
             if (Py_TYPE(function) == &PyFunction_Type && tstate->interp->eval_frame == NULL) {
-                int code_flags = ((PyCodeObject*)PyFunction_GET_CODE(function))->co_flags;
+                PyFunctionObject *func = (PyFunctionObject *)function;
+                int code_flags = ((PyCodeObject*)func->func_code)->co_flags;
                 int is_generator = code_flags & (CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR);
                 if (!is_generator) {
                     PyObject *locals = code_flags & CO_OPTIMIZED ? NULL : PyFunction_GET_GLOBALS(function);

diff --git a/Python/specialize.c b/Python/specialize.c
@@ -1,5 +1,6 @@
 #include "Python.h"
 #include "pycore_code.h"
+#include "pycore_function.h"
 #include "pycore_dict.h"
 #include "pycore_long.h"
 #include "pycore_moduleobject.h"