bpo-45963: Make space for the InterpreterFrame of a generator in that…

… generator. (GH-29891)

* Make generator, coroutine and async gen structs all the same size.

* Store interpreter frame in generator (and coroutine). Reduces the number of allocations neeeded for a generator from two to one.

Include/cpython/genobject.h

@@ -14,7 +14,6 @@ extern "C" {
 #define _PyGenObject_HEAD(prefix)                                           \
     PyObject_HEAD                                                           \
     /* Note: gi_frame can be NULL if the generator is "finished" */         \
-    struct _interpreter_frame *prefix##_xframe;                             \
     /* The code object backing the generator */                             \
     PyCodeObject *prefix##_code;                                            \
     /* List of weak reference. */                                           \
@@ -23,7 +22,14 @@ extern "C" {
     PyObject *prefix##_name;                                                \
     /* Qualified name of the generator. */                                  \
     PyObject *prefix##_qualname;                                            \
-    _PyErr_StackItem prefix##_exc_state;
+    _PyErr_StackItem prefix##_exc_state;                                    \
+    PyObject *prefix##_origin_or_finalizer;                                 \
+    char prefix##_hooks_inited;                                             \
+    char prefix##_closed;                                                   \
+    char prefix##_running_async;                                            \
+    /* The frame */                                                         \
+    char prefix##_frame_valid;                                              \
+    PyObject *prefix##_iframe[1];
 
 typedef struct {
     /* The gi_ prefix is intended to remind of generator-iterator. */
@@ -48,7 +54,6 @@ PyAPI_FUNC(void) _PyGen_Finalize(PyObject *self);
 
 typedef struct {
     _PyGenObject_HEAD(cr)
-    PyObject *cr_origin;
 } PyCoroObject;
 
 PyAPI_DATA(PyTypeObject) PyCoro_Type;
@@ -64,18 +69,6 @@ PyAPI_FUNC(PyObject *) PyCoro_New(PyFrameObject *,
 
 typedef struct {
     _PyGenObject_HEAD(ag)
-    PyObject *ag_finalizer;
-
-    /* Flag is set to 1 when hooks set up by sys.set_asyncgen_hooks
-       were called on the generator, to avoid calling them more
-       than once. */
-    int ag_hooks_inited;
-
-    /* Flag is set to 1 when aclose() is called for the first time, or
-       when a StopAsyncIteration exception is raised. */
-    int ag_closed;
-
-    int ag_running_async;
 } PyAsyncGenObject;
 
 PyAPI_DATA(PyTypeObject) PyAsyncGen_Type;

Include/internal/pycore_ceval.h

@@ -113,7 +113,7 @@ static inline void _Py_LeaveRecursiveCall_inline(void)  {
 
 struct _interpreter_frame *_PyEval_GetFrame(void);
 
-PyObject *_Py_MakeCoro(PyFunctionObject *func, struct _interpreter_frame *);
+PyObject *_Py_MakeCoro(PyFunctionObject *func);
 
 #ifdef __cplusplus
 }

Include/internal/pycore_frame.h

@@ -74,7 +74,7 @@ static inline void _PyFrame_StackPush(InterpreterFrame *f, PyObject *value) {
 
 #define FRAME_SPECIALS_SIZE ((sizeof(InterpreterFrame)-1)/sizeof(PyObject *))
 
-InterpreterFrame *_PyFrame_Copy(InterpreterFrame *frame);
+void _PyFrame_Copy(InterpreterFrame *src, InterpreterFrame *dest);
 
 static inline void
 _PyFrame_InitializeSpecials(

Lib/test/test_sys.py

@@ -1340,7 +1340,7 @@ def bar(cls):
             check(bar, size('PP'))
         # generator
         def get_gen(): yield 1
-        check(get_gen(), size('P2PPP4P'))
+        check(get_gen(), size('P2PPP4P4c8P2iciP'))
         # iterator
         check(iter('abc'), size('lP'))
         # callable-iterator