bpo-44525: Copy free variables in bytecode to allow calls to inner functions to be specialized (GH-29595)

* Make internal APIs that take PyFrameConstructor take a PyFunctionObject instead.

* Add reference to function to frame, borrow references to builtins and globals.

* Add COPY_FREE_VARS instruction to allow specialization of calls to inner functions.

Include/internal/pycore_ceval.h

@@ -52,7 +52,7 @@ _PyEval_EvalFrame(PyThreadState *tstate, struct _interpreter_frame *frame, int t
 
 extern PyObject *
 _PyEval_Vector(PyThreadState *tstate,
-            PyFrameConstructor *desc, PyObject *locals,
+            PyFunctionObject *func, PyObject *locals,
             PyObject* const* args, size_t argcount,
             PyObject *kwnames);
 
@@ -113,7 +113,7 @@ static inline void _Py_LeaveRecursiveCall_inline(void)  {
 
 struct _interpreter_frame *_PyEval_GetFrame(void);
 
-PyObject *_Py_MakeCoro(PyFrameConstructor *, struct _interpreter_frame *);
+PyObject *_Py_MakeCoro(PyFunctionObject *func, struct _interpreter_frame *);
 
 #ifdef __cplusplus
 }

Include/internal/pycore_frame.h

@@ -20,13 +20,13 @@ enum _framestate {
 typedef signed char PyFrameState;
 
 typedef struct _interpreter_frame {
-    PyObject *f_globals;
-    PyObject *f_builtins;
-    PyObject *f_locals;
-    PyCodeObject *f_code;
-    PyFrameObject *frame_obj;
-    /* Borrowed reference to a generator, or NULL */
-    PyObject *generator;
+    PyFunctionObject *f_func; /* Strong reference */
+    PyObject *f_globals; /* Borrowed reference */
+    PyObject *f_builtins; /* Borrowed reference */
+    PyObject *f_locals; /* Strong reference, may be NULL */
+    PyCodeObject *f_code; /* Strong reference */
+    PyFrameObject *frame_obj; /* Strong reference, may be NULL */
+    PyObject *generator; /* Borrowed reference, may be NULL */
     struct _interpreter_frame *previous;
     int f_lasti;       /* Last instruction if called */
     int stacktop;     /* Offset of TOS from localsplus  */
@@ -70,16 +70,18 @@ static inline void _PyFrame_StackPush(InterpreterFrame *f, PyObject *value) {
 #define FRAME_SPECIALS_SIZE ((sizeof(InterpreterFrame)-1)/sizeof(PyObject *))
 
 InterpreterFrame *
-_PyInterpreterFrame_HeapAlloc(PyFrameConstructor *con, PyObject *locals);
+_PyInterpreterFrame_HeapAlloc(PyFunctionObject *func, PyObject *locals);
 
 static inline void
 _PyFrame_InitializeSpecials(
-    InterpreterFrame *frame, PyFrameConstructor *con,
+    InterpreterFrame *frame, PyFunctionObject *func,
     PyObject *locals, int nlocalsplus)
 {
-    frame->f_code = (PyCodeObject *)Py_NewRef(con->fc_code);
-    frame->f_builtins = Py_NewRef(con->fc_builtins);
-    frame->f_globals = Py_NewRef(con->fc_globals);
+    Py_INCREF(func);
+    frame->f_func = func;
+    frame->f_code = (PyCodeObject *)Py_NewRef(func->func_code);
+    frame->f_builtins = func->func_builtins;
+    frame->f_globals = func->func_globals;
     frame->f_locals = Py_XNewRef(locals);
     frame->stacktop = nlocalsplus;
     frame->frame_obj = NULL;
@@ -150,7 +152,7 @@ void
 _PyFrame_LocalsToFast(InterpreterFrame *frame, int clear);
 
 InterpreterFrame *_PyThreadState_PushFrame(
-    PyThreadState *tstate, PyFrameConstructor *con, PyObject *locals);
+    PyThreadState *tstate, PyFunctionObject *func, PyObject *locals);
 
 extern InterpreterFrame *
 _PyThreadState_BumpFramePointerSlow(PyThreadState *tstate, size_t size);

Include/internal/pycore_function.h

@@ -0,0 +1,11 @@
+#ifndef Py_INTERNAL_FUNCTION_H
+#define Py_INTERNAL_FUNCTION_H
+
+
+#include "Python.h"
+
+PyFunctionObject *
+_PyFunction_FromConstructor(PyFrameConstructor *constr);
+
+
+#endif /* !Py_INTERNAL_FUNCTION_H */