GH-96421: Insert shim frame on entry to interpreter (GH-96319)

* Adds EXIT_INTERPRETER instruction to exit PyEval_EvalDefault()

* Simplifies RETURN_VALUE, YIELD_VALUE and RETURN_GENERATOR instructions as they no longer need to check for entry frames.

9 files changed, 217 insertions, 219 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index c1f416e..ed12b94 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -97,8 +97,7 @@ dummy_func(
     PyObject *consts,
     _Py_CODEUNIT *next_instr,
     PyObject **stack_pointer,
-    CallShape call_shape,
-    _Py_CODEUNIT *first_instr,
+    PyObject *kwnames,
     int throwflag,
     binaryfunc binary_ops[]
 )
@@ -618,32 +617,34 @@ dummy_func(
         }
 
         // stack effect: (__0 -- )
-        inst(RETURN_VALUE) {
+        inst(INTERPRETER_EXIT) {
+            assert(frame == &entry_frame);
+            assert(_PyFrame_IsIncomplete(frame));
             PyObject *retval = POP();
             assert(EMPTY());
-            _PyFrame_SetStackPointer(frame, stack_pointer);
-            TRACE_FUNCTION_EXIT();
-            DTRACE_FUNCTION_EXIT();
-            _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                frame = cframe.current_frame = pop_frame(tstate, frame);
-                _PyFrame_StackPush(frame, retval);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            if (frame->owner == FRAME_OWNED_BY_GENERATOR) {
-                PyGenObject *gen = _PyFrame_GetGenerator(frame);
-                tstate->exc_info = gen->gi_exc_state.previous_item;
-                gen->gi_exc_state.previous_item = NULL;
-            }
             /* Restore previous cframe and return. */
             tstate->cframe = cframe.previous;
             tstate->cframe->use_tracing = cframe.use_tracing;
             assert(tstate->cframe->current_frame == frame->previous);
             assert(!_PyErr_Occurred(tstate));
+            _Py_LeaveRecursiveCallTstate(tstate);
             return retval;
         }
 
+        // stack effect: (__0 -- )
+        inst(RETURN_VALUE) {
+            PyObject *retval = POP();
+            assert(EMPTY());
+            _PyFrame_SetStackPointer(frame, stack_pointer);
+            TRACE_FUNCTION_EXIT();
+            DTRACE_FUNCTION_EXIT();
+            _Py_LeaveRecursiveCallPy(tstate);
+            assert(frame != &entry_frame);
+            frame = cframe.current_frame = pop_frame(tstate, frame);
+            _PyFrame_StackPush(frame, retval);
+            goto resume_frame;
+        }
+
         // stack effect: ( -- )
         inst(GET_AITER) {
             unaryfunc getter = NULL;
@@ -775,6 +776,7 @@ dummy_func(
 
         // error: SEND stack effect depends on jump flag
         inst(SEND) {
+            assert(frame != &entry_frame);
             assert(STACK_LEVEL() >= 2);
             PyObject *v = POP();
             PyObject *receiver = TOP();
@@ -839,6 +841,7 @@ dummy_func(
             // The compiler treats any exception raised here as a failed close()
             // or throw() call.
             assert(oparg == STACK_LEVEL());
+            assert(frame != &entry_frame);
             PyObject *retval = POP();
             PyGenObject *gen = _PyFrame_GetGenerator(frame);
             gen->gi_frame_state = FRAME_SUSPENDED;
@@ -848,19 +851,12 @@ dummy_func(
             tstate->exc_info = gen->gi_exc_state.previous_item;
             gen->gi_exc_state.previous_item = NULL;
             _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                frame = cframe.current_frame = frame->previous;
-                frame->prev_instr -= frame->yield_offset;
-                _PyFrame_StackPush(frame, retval);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            /* Restore previous cframe and return. */
-            tstate->cframe = cframe.previous;
-            tstate->cframe->use_tracing = cframe.use_tracing;
-            assert(tstate->cframe->current_frame == frame->previous);
-            assert(!_PyErr_Occurred(tstate));
-            return retval;
+            _PyInterpreterFrame *gen_frame = frame;
+            frame = cframe.current_frame = frame->previous;
+            gen_frame->previous = NULL;
+            frame->prev_instr -= frame->yield_offset;
+            _PyFrame_StackPush(frame, retval);
+            goto resume_frame;
         }
 
         // stack effect: (__0 -- )
@@ -876,7 +872,7 @@ dummy_func(
             if (oparg) {
                 PyObject *lasti = PEEK(oparg + 1);
                 if (PyLong_Check(lasti)) {
-                    frame->prev_instr = first_instr + PyLong_AsLong(lasti);
+                    frame->prev_instr = _PyCode_CODE(frame->f_code) + PyLong_AsLong(lasti);
                     assert(!_PyErr_Occurred(tstate));
                 }
                 else {
@@ -2696,12 +2692,10 @@ dummy_func(
             gen->gi_exc_state.previous_item = tstate->exc_info;
             tstate->exc_info = &gen->gi_exc_state;
             gen_frame->previous = frame;
-            gen_frame->is_entry = false;
             frame = cframe.current_frame = gen_frame;
             goto start_frame;
         }
 
-
         // stack effect: ( -- __0)
         inst(BEFORE_ASYNC_WITH) {
             PyObject *mgr = TOP();
@@ -2929,9 +2923,9 @@ dummy_func(
 
         // stack effect: ( -- )
         inst(KW_NAMES) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg < PyTuple_GET_SIZE(consts));
-            call_shape.kwnames = GETITEM(consts, oparg);
+            kwnames = GETITEM(consts, oparg);
         }
 
         // stack effect: (__0, __array[oparg] -- )
@@ -2943,7 +2937,7 @@ dummy_func(
                 int nargs = oparg + is_meth;
                 PyObject *callable = PEEK(nargs + 1);
                 next_instr--;
-                _Py_Specialize_Call(callable, next_instr, nargs, call_shape.kwnames);
+                _Py_Specialize_Call(callable, next_instr, nargs, kwnames);
                 DISPATCH_SAME_OPARG();
             }
             STAT_INC(CALL, deferred);
@@ -2972,9 +2966,9 @@ dummy_func(
                 STACK_SHRINK(total_args);
                 _PyInterpreterFrame *new_frame = _PyEvalFramePushAndInit(
                     tstate, (PyFunctionObject *)function, locals,
-                    stack_pointer, positional_args, call_shape.kwnames
+                    stack_pointer, positional_args, kwnames
                 );
-                call_shape.kwnames = NULL;
+                kwnames = NULL;
                 STACK_SHRINK(2-is_meth);
                 // The frame has stolen all the arguments from the stack,
                 // so there is no need to clean them up.
@@ -2994,15 +2988,15 @@ dummy_func(
             if (cframe.use_tracing) {
                 res = trace_call_function(
                     tstate, function, stack_pointer-total_args,
-                    positional_args, call_shape.kwnames);
+                    positional_args, kwnames);
             }
             else {
                 res = PyObject_Vectorcall(
                     function, stack_pointer-total_args,
                     positional_args | PY_VECTORCALL_ARGUMENTS_OFFSET,
-                    call_shape.kwnames);
+                    kwnames);
             }
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
             Py_DECREF(function);
             /* Clear the stack */
@@ -3021,7 +3015,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_PY_EXACT_ARGS) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             DEOPT_IF(tstate->interp->eval_frame, CALL);
             _PyCallCache *cache = (_PyCallCache *)next_instr;
             int is_meth = is_method(stack_pointer, oparg);
@@ -3054,7 +3048,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_PY_WITH_DEFAULTS) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             DEOPT_IF(tstate->interp->eval_frame, CALL);
             _PyCallCache *cache = (_PyCallCache *)next_instr;
             int is_meth = is_method(stack_pointer, oparg);
@@ -3094,7 +3088,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_TYPE_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(cframe.use_tracing == 0);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
@@ -3112,7 +3106,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_STR_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(cframe.use_tracing == 0);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
@@ -3134,7 +3128,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_TUPLE_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
             PyObject *callable = PEEK(2);
@@ -3166,8 +3160,8 @@ dummy_func(
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             STACK_SHRINK(total_args);
             PyObject *res = tp->tp_vectorcall((PyObject *)tp, stack_pointer,
-                                              total_args-kwnames_len, call_shape.kwnames);
-            call_shape.kwnames = NULL;
+                                              total_args-kwnames_len, kwnames);
+            kwnames = NULL;
             /* Free the arguments. */
             for (int i = 0; i < total_args; i++) {
                 Py_DECREF(stack_pointer[i]);
@@ -3185,7 +3179,7 @@ dummy_func(
         inst(CALL_NO_KW_BUILTIN_O) {
             assert(cframe.use_tracing == 0);
             /* Builtin METH_O functions */
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             DEOPT_IF(total_args != 1, CALL);
@@ -3219,7 +3213,7 @@ dummy_func(
         inst(CALL_NO_KW_BUILTIN_FAST) {
             assert(cframe.use_tracing == 0);
             /* Builtin METH_FASTCALL functions, without keywords */
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyObject *callable = PEEK(total_args + 1);
@@ -3276,10 +3270,10 @@ dummy_func(
                 PyCFunction_GET_SELF(callable),
                 stack_pointer,
                 total_args - KWNAMES_LEN(),
-                call_shape.kwnames
+                kwnames
             );
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
 
             /* Free the arguments. */
             for (int i = 0; i < total_args; i++) {
@@ -3297,7 +3291,7 @@ dummy_func(
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_LEN) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             /* len(o) */
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3327,7 +3321,7 @@ dummy_func(
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_ISINSTANCE) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             /* isinstance(o, o2) */
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3360,7 +3354,7 @@ dummy_func(
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_LIST_APPEND) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 1);
             PyObject *callable = PEEK(3);
             PyInterpreterState *interp = _PyInterpreterState_GET();
@@ -3382,7 +3376,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_METHOD_DESCRIPTOR_O) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyMethodDescrObject *callable =
@@ -3435,9 +3429,9 @@ dummy_func(
             _PyCFunctionFastWithKeywords cfunc =
                 (_PyCFunctionFastWithKeywords)(void(*)(void))meth->ml_meth;
             PyObject *res = cfunc(self, stack_pointer, nargs - KWNAMES_LEN(),
-                                  call_shape.kwnames);
+                                  kwnames);
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
 
             /* Free the arguments. */
             for (int i = 0; i < nargs; i++) {
@@ -3455,7 +3449,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_METHOD_DESCRIPTOR_NOARGS) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 0 || oparg == 1);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3489,7 +3483,7 @@ dummy_func(
 
         // stack effect: (__0, __array[oparg] -- )
         inst(CALL_NO_KW_METHOD_DESCRIPTOR_FAST) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyMethodDescrObject *callable =
@@ -3606,25 +3600,12 @@ dummy_func(
             gen->gi_frame_state = FRAME_CREATED;
             gen_frame->owner = FRAME_OWNED_BY_GENERATOR;
             _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                _PyInterpreterFrame *prev = frame->previous;
-                _PyThreadState_PopFrame(tstate, frame);
-                frame = cframe.current_frame = prev;
-                _PyFrame_StackPush(frame, (PyObject *)gen);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            /* Make sure that frame is in a valid state */
-            frame->stacktop = 0;
-            frame->f_locals = NULL;
-            Py_INCREF(frame->f_funcobj);
-            Py_INCREF(frame->f_code);
-            /* Restore previous cframe and return. */
-            tstate->cframe = cframe.previous;
-            tstate->cframe->use_tracing = cframe.use_tracing;
-            assert(tstate->cframe->current_frame == frame->previous);
-            assert(!_PyErr_Occurred(tstate));
-            return (PyObject *)gen;
+            assert(frame != &entry_frame);
+            _PyInterpreterFrame *prev = frame->previous;
+            _PyThreadState_PopFrame(tstate, frame);
+            frame = cframe.current_frame = prev;
+            _PyFrame_StackPush(frame, (PyObject *)gen);
+            goto resume_frame;
         }
 
         // error: BUILD_SLICE has irregular stack effect
diff --git a/Python/ceval.c b/Python/ceval.c
index 8462cb1..bff8b5c 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -155,7 +155,10 @@ static void
 lltrace_resume_frame(_PyInterpreterFrame *frame)
 {
     PyObject *fobj = frame->f_funcobj;
-    if (fobj == NULL || !PyFunction_Check(fobj)) {
+    if (frame->owner == FRAME_OWNED_BY_CSTACK ||
+        fobj == NULL ||
+        !PyFunction_Check(fobj)
+    ) {
         printf("\nResuming frame.");
         return;
     }
@@ -733,13 +736,13 @@ GETITEM(PyObject *v, Py_ssize_t i) {
 /* Code access macros */
 
 /* The integer overflow is checked by an assertion below. */
-#define INSTR_OFFSET() ((int)(next_instr - first_instr))
+#define INSTR_OFFSET() ((int)(next_instr - _PyCode_CODE(frame->f_code)))
 #define NEXTOPARG()  do { \
         _Py_CODEUNIT word = *next_instr; \
         opcode = _Py_OPCODE(word); \
         oparg = _Py_OPARG(word); \
     } while (0)
-#define JUMPTO(x)       (next_instr = first_instr + (x))
+#define JUMPTO(x)       (next_instr = _PyCode_CODE(frame->f_code) + (x))
 #define JUMPBY(x)       (next_instr += (x))
 
 /* OpCode prediction macros
@@ -1037,18 +1040,11 @@ static inline void _Py_LeaveRecursiveCallPy(PyThreadState *tstate)  {
 }
 
 
-/* It is only between the KW_NAMES instruction and the following CALL,
- * that this has any meaning.
- */
-typedef struct {
-    PyObject *kwnames;
-} CallShape;
-
 // GH-89279: Must be a macro to be sure it's inlined by MSVC.
 #define is_method(stack_pointer, args) (PEEK((args)+2) != NULL)
 
 #define KWNAMES_LEN() \
-    (call_shape.kwnames == NULL ? 0 : ((int)PyTuple_GET_SIZE(call_shape.kwnames)))
+    (kwnames == NULL ? 0 : ((int)PyTuple_GET_SIZE(kwnames)))
 
 PyObject* _Py_HOT_FUNCTION
 _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int throwflag)
@@ -1074,8 +1070,8 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
 #endif
 
     _PyCFrame cframe;
-    CallShape call_shape;
-    call_shape.kwnames = NULL; // Borrowed reference. Reset by CALL instructions.
+    _PyInterpreterFrame  entry_frame;
+    PyObject *kwnames = NULL; // Borrowed reference. Reset by CALL instructions.
 
     /* WARNING: Because the _PyCFrame lives on the C stack,
      * but can be accessed from a heap allocated object (tstate)
@@ -1086,9 +1082,24 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
     cframe.previous = prev_cframe;
     tstate->cframe = &cframe;
 
-    frame->is_entry = true;
+    assert(tstate->interp->interpreter_trampoline != NULL);
+#ifdef Py_DEBUG
+    /* Set these to invalid but identifiable values for debugging. */
+    entry_frame.f_funcobj = (PyObject*)0xaaa0;
+    entry_frame.f_locals = (PyObject*)0xaaa1;
+    entry_frame.frame_obj = (PyFrameObject*)0xaaa2;
+    entry_frame.f_globals = (PyObject*)0xaaa3;
+    entry_frame.f_builtins = (PyObject*)0xaaa4;
+#endif
+    entry_frame.f_code = tstate->interp->interpreter_trampoline;
+    entry_frame.prev_instr =
+        _PyCode_CODE(tstate->interp->interpreter_trampoline);
+    entry_frame.stacktop = 0;
+    entry_frame.owner = FRAME_OWNED_BY_CSTACK;
+    entry_frame.yield_offset = 0;
     /* Push frame */
-    frame->previous = prev_cframe->current_frame;
+    entry_frame.previous = prev_cframe->current_frame;
+    frame->previous = &entry_frame;
     cframe.current_frame = frame;
 
     if (_Py_EnterRecursiveCallTstate(tstate, "")) {
@@ -1112,7 +1123,6 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
 
     PyObject *names;
     PyObject *consts;
-    _Py_CODEUNIT *first_instr;
     _Py_CODEUNIT *next_instr;
     PyObject **stack_pointer;
 
@@ -1122,7 +1132,6 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
         PyCodeObject *co = frame->f_code; \
         names = co->co_names; \
         consts = co->co_consts; \
-        first_instr = _PyCode_CODE(co); \
     } \
     assert(_PyInterpreterFrame_LASTI(frame) >= -1); \
     /* Jump back to the last instruction executed... */ \
@@ -1147,14 +1156,16 @@ resume_frame:
 
 #ifdef LLTRACE
     {
-        int r = PyDict_Contains(GLOBALS(), &_Py_ID(__lltrace__));
-        if (r < 0) {
-            goto exit_unwind;
+        if (frame != &entry_frame) {
+            int r = PyDict_Contains(GLOBALS(), &_Py_ID(__lltrace__));
+            if (r < 0) {
+                goto exit_unwind;
+            }
+            lltrace = r;
+        }
+        if (lltrace) {
+            lltrace_resume_frame(frame);
         }
-        lltrace = r;
-    }
-    if (lltrace) {
-        lltrace_resume_frame(frame);
     }
 #endif
 
@@ -1313,7 +1324,7 @@ pop_2_error:
 pop_1_error:
     STACK_SHRINK(1);
 error:
-        call_shape.kwnames = NULL;
+        kwnames = NULL;
         /* Double-check exception status. */
 #ifdef NDEBUG
         if (!_PyErr_Occurred(tstate)) {
@@ -1325,6 +1336,7 @@ error:
 #endif
 
         /* Log traceback info. */
+        assert(frame != &entry_frame);
         if (!_PyFrame_IsIncomplete(frame)) {
             PyFrameObject *f = _PyFrame_GetFrameObject(frame);
             if (f != NULL) {
@@ -1397,12 +1409,9 @@ exception_unwind:
 exit_unwind:
     assert(_PyErr_Occurred(tstate));
     _Py_LeaveRecursiveCallPy(tstate);
-    if (frame->is_entry) {
-        if (frame->owner == FRAME_OWNED_BY_GENERATOR) {
-            PyGenObject *gen = _PyFrame_GetGenerator(frame);
-            tstate->exc_info = gen->gi_exc_state.previous_item;
-            gen->gi_exc_state.previous_item = NULL;
-        }
+    assert(frame != &entry_frame);
+    frame = cframe.current_frame = pop_frame(tstate, frame);
+    if (frame == &entry_frame) {
         /* Restore previous cframe and exit */
         tstate->cframe = cframe.previous;
         tstate->cframe->use_tracing = cframe.use_tracing;
@@ -1410,7 +1419,6 @@ exit_unwind:
         _Py_LeaveRecursiveCallTstate(tstate);
         return NULL;
     }
-    frame = cframe.current_frame = pop_frame(tstate, frame);
 
 resume_with_error:
     SET_LOCALS_FROM_FRAME();
@@ -2038,13 +2046,7 @@ _PyEval_Vector(PyThreadState *tstate, PyFunctionObject *func,
         return NULL;
     }
     EVAL_CALL_STAT_INC(EVAL_CALL_VECTOR);
-    PyObject *retval = _PyEval_EvalFrame(tstate, frame, 0);
-    assert(
-        _PyFrame_GetStackPointer(frame) == _PyFrame_Stackbase(frame) ||
-        _PyFrame_GetStackPointer(frame) == frame->localsplus
-    );
-    _PyEvalFrameClearAndPop(tstate, frame);
-    return retval;
+    return _PyEval_EvalFrame(tstate, frame, 0);
 }
 
 /* Legacy API */
diff --git a/Python/compile.c b/Python/compile.c
index 177409a..c71563f 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1256,6 +1256,8 @@ stack_effect(int opcode, int oparg, int jump)
             return 1;
         case BINARY_OP:
             return -1;
+        case INTERPRETER_EXIT:
+            return -1;
         default:
             return PY_INVALID_STACK_EFFECT;
     }
diff --git a/Python/frame.c b/Python/frame.c
index 89f084b..52f6ef4 100644
--- a/Python/frame.c
+++ b/Python/frame.c
@@ -80,6 +80,7 @@ _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest)
 static void
 take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
 {
+    assert(frame->owner != FRAME_OWNED_BY_CSTACK);
     assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);
     assert(frame->owner != FRAME_CLEARED);
     Py_ssize_t size = ((char*)&frame->localsplus[frame->stacktop]) - (char *)frame;
@@ -99,7 +100,9 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
     while (prev && _PyFrame_IsIncomplete(prev)) {
         prev = prev->previous;
     }
+    frame->previous = NULL;
     if (prev) {
+        assert(prev->owner != FRAME_OWNED_BY_CSTACK);
         /* Link PyFrameObjects.f_back and remove link through _PyInterpreterFrame.previous */
         PyFrameObject *back = _PyFrame_GetFrameObject(prev);
         if (back == NULL) {
@@ -111,7 +114,6 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
         else {
             f->f_back = (PyFrameObject *)Py_NewRef(back);
         }
-        frame->previous = NULL;
     }
     if (!_PyObject_GC_IS_TRACKED((PyObject *)f)) {
         _PyObject_GC_TRACK((PyObject *)f);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index d09384e..0487851 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -611,32 +611,33 @@
             goto error;
         }
 
-        TARGET(RETURN_VALUE) {
+        TARGET(INTERPRETER_EXIT) {
+            assert(frame == &entry_frame);
+            assert(_PyFrame_IsIncomplete(frame));
             PyObject *retval = POP();
             assert(EMPTY());
-            _PyFrame_SetStackPointer(frame, stack_pointer);
-            TRACE_FUNCTION_EXIT();
-            DTRACE_FUNCTION_EXIT();
-            _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                frame = cframe.current_frame = pop_frame(tstate, frame);
-                _PyFrame_StackPush(frame, retval);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            if (frame->owner == FRAME_OWNED_BY_GENERATOR) {
-                PyGenObject *gen = _PyFrame_GetGenerator(frame);
-                tstate->exc_info = gen->gi_exc_state.previous_item;
-                gen->gi_exc_state.previous_item = NULL;
-            }
             /* Restore previous cframe and return. */
             tstate->cframe = cframe.previous;
             tstate->cframe->use_tracing = cframe.use_tracing;
             assert(tstate->cframe->current_frame == frame->previous);
             assert(!_PyErr_Occurred(tstate));
+            _Py_LeaveRecursiveCallTstate(tstate);
             return retval;
         }
 
+        TARGET(RETURN_VALUE) {
+            PyObject *retval = POP();
+            assert(EMPTY());
+            _PyFrame_SetStackPointer(frame, stack_pointer);
+            TRACE_FUNCTION_EXIT();
+            DTRACE_FUNCTION_EXIT();
+            _Py_LeaveRecursiveCallPy(tstate);
+            assert(frame != &entry_frame);
+            frame = cframe.current_frame = pop_frame(tstate, frame);
+            _PyFrame_StackPush(frame, retval);
+            goto resume_frame;
+        }
+
         TARGET(GET_AITER) {
             unaryfunc getter = NULL;
             PyObject *iter = NULL;
@@ -768,6 +769,7 @@
         }
 
         TARGET(SEND) {
+            assert(frame != &entry_frame);
             assert(STACK_LEVEL() >= 2);
             PyObject *v = POP();
             PyObject *receiver = TOP();
@@ -832,6 +834,7 @@
             // The compiler treats any exception raised here as a failed close()
             // or throw() call.
             assert(oparg == STACK_LEVEL());
+            assert(frame != &entry_frame);
             PyObject *retval = POP();
             PyGenObject *gen = _PyFrame_GetGenerator(frame);
             gen->gi_frame_state = FRAME_SUSPENDED;
@@ -841,19 +844,12 @@
             tstate->exc_info = gen->gi_exc_state.previous_item;
             gen->gi_exc_state.previous_item = NULL;
             _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                frame = cframe.current_frame = frame->previous;
-                frame->prev_instr -= frame->yield_offset;
-                _PyFrame_StackPush(frame, retval);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            /* Restore previous cframe and return. */
-            tstate->cframe = cframe.previous;
-            tstate->cframe->use_tracing = cframe.use_tracing;
-            assert(tstate->cframe->current_frame == frame->previous);
-            assert(!_PyErr_Occurred(tstate));
-            return retval;
+            _PyInterpreterFrame *gen_frame = frame;
+            frame = cframe.current_frame = frame->previous;
+            gen_frame->previous = NULL;
+            frame->prev_instr -= frame->yield_offset;
+            _PyFrame_StackPush(frame, retval);
+            goto resume_frame;
         }
 
         TARGET(POP_EXCEPT) {
@@ -868,7 +864,7 @@
             if (oparg) {
                 PyObject *lasti = PEEK(oparg + 1);
                 if (PyLong_Check(lasti)) {
-                    frame->prev_instr = first_instr + PyLong_AsLong(lasti);
+                    frame->prev_instr = _PyCode_CODE(frame->f_code) + PyLong_AsLong(lasti);
                     assert(!_PyErr_Occurred(tstate));
                 }
                 else {
@@ -2690,7 +2686,6 @@
             gen->gi_exc_state.previous_item = tstate->exc_info;
             tstate->exc_info = &gen->gi_exc_state;
             gen_frame->previous = frame;
-            gen_frame->is_entry = false;
             frame = cframe.current_frame = gen_frame;
             goto start_frame;
         }
@@ -2919,9 +2914,9 @@
         }
 
         TARGET(KW_NAMES) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg < PyTuple_GET_SIZE(consts));
-            call_shape.kwnames = GETITEM(consts, oparg);
+            kwnames = GETITEM(consts, oparg);
             DISPATCH();
         }
 
@@ -2934,7 +2929,7 @@
                 int nargs = oparg + is_meth;
                 PyObject *callable = PEEK(nargs + 1);
                 next_instr--;
-                _Py_Specialize_Call(callable, next_instr, nargs, call_shape.kwnames);
+                _Py_Specialize_Call(callable, next_instr, nargs, kwnames);
                 DISPATCH_SAME_OPARG();
             }
             STAT_INC(CALL, deferred);
@@ -2963,9 +2958,9 @@
                 STACK_SHRINK(total_args);
                 _PyInterpreterFrame *new_frame = _PyEvalFramePushAndInit(
                     tstate, (PyFunctionObject *)function, locals,
-                    stack_pointer, positional_args, call_shape.kwnames
+                    stack_pointer, positional_args, kwnames
                 );
-                call_shape.kwnames = NULL;
+                kwnames = NULL;
                 STACK_SHRINK(2-is_meth);
                 // The frame has stolen all the arguments from the stack,
                 // so there is no need to clean them up.
@@ -2985,15 +2980,15 @@
             if (cframe.use_tracing) {
                 res = trace_call_function(
                     tstate, function, stack_pointer-total_args,
-                    positional_args, call_shape.kwnames);
+                    positional_args, kwnames);
             }
             else {
                 res = PyObject_Vectorcall(
                     function, stack_pointer-total_args,
                     positional_args | PY_VECTORCALL_ARGUMENTS_OFFSET,
-                    call_shape.kwnames);
+                    kwnames);
             }
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
             Py_DECREF(function);
             /* Clear the stack */
@@ -3013,7 +3008,7 @@
 
         TARGET(CALL_PY_EXACT_ARGS) {
             PREDICTED(CALL_PY_EXACT_ARGS);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             DEOPT_IF(tstate->interp->eval_frame, CALL);
             _PyCallCache *cache = (_PyCallCache *)next_instr;
             int is_meth = is_method(stack_pointer, oparg);
@@ -3045,7 +3040,7 @@
         }
 
         TARGET(CALL_PY_WITH_DEFAULTS) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             DEOPT_IF(tstate->interp->eval_frame, CALL);
             _PyCallCache *cache = (_PyCallCache *)next_instr;
             int is_meth = is_method(stack_pointer, oparg);
@@ -3084,7 +3079,7 @@
         }
 
         TARGET(CALL_NO_KW_TYPE_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(cframe.use_tracing == 0);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
@@ -3102,7 +3097,7 @@
         }
 
         TARGET(CALL_NO_KW_STR_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(cframe.use_tracing == 0);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
@@ -3124,7 +3119,7 @@
         }
 
         TARGET(CALL_NO_KW_TUPLE_1) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 1);
             DEOPT_IF(is_method(stack_pointer, 1), CALL);
             PyObject *callable = PEEK(2);
@@ -3156,8 +3151,8 @@
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             STACK_SHRINK(total_args);
             PyObject *res = tp->tp_vectorcall((PyObject *)tp, stack_pointer,
-                                              total_args-kwnames_len, call_shape.kwnames);
-            call_shape.kwnames = NULL;
+                                              total_args-kwnames_len, kwnames);
+            kwnames = NULL;
             /* Free the arguments. */
             for (int i = 0; i < total_args; i++) {
                 Py_DECREF(stack_pointer[i]);
@@ -3175,7 +3170,7 @@
         TARGET(CALL_NO_KW_BUILTIN_O) {
             assert(cframe.use_tracing == 0);
             /* Builtin METH_O functions */
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             DEOPT_IF(total_args != 1, CALL);
@@ -3209,7 +3204,7 @@
         TARGET(CALL_NO_KW_BUILTIN_FAST) {
             assert(cframe.use_tracing == 0);
             /* Builtin METH_FASTCALL functions, without keywords */
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyObject *callable = PEEK(total_args + 1);
@@ -3266,10 +3261,10 @@
                 PyCFunction_GET_SELF(callable),
                 stack_pointer,
                 total_args - KWNAMES_LEN(),
-                call_shape.kwnames
+                kwnames
             );
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
 
             /* Free the arguments. */
             for (int i = 0; i < total_args; i++) {
@@ -3287,7 +3282,7 @@
 
         TARGET(CALL_NO_KW_LEN) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             /* len(o) */
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3317,7 +3312,7 @@
 
         TARGET(CALL_NO_KW_ISINSTANCE) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             /* isinstance(o, o2) */
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3350,7 +3345,7 @@
 
         TARGET(CALL_NO_KW_LIST_APPEND) {
             assert(cframe.use_tracing == 0);
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 1);
             PyObject *callable = PEEK(3);
             PyInterpreterState *interp = _PyInterpreterState_GET();
@@ -3372,7 +3367,7 @@
         }
 
         TARGET(CALL_NO_KW_METHOD_DESCRIPTOR_O) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyMethodDescrObject *callable =
@@ -3425,9 +3420,9 @@
             _PyCFunctionFastWithKeywords cfunc =
                 (_PyCFunctionFastWithKeywords)(void(*)(void))meth->ml_meth;
             PyObject *res = cfunc(self, stack_pointer, nargs - KWNAMES_LEN(),
-                                  call_shape.kwnames);
+                                  kwnames);
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
-            call_shape.kwnames = NULL;
+            kwnames = NULL;
 
             /* Free the arguments. */
             for (int i = 0; i < nargs; i++) {
@@ -3445,7 +3440,7 @@
         }
 
         TARGET(CALL_NO_KW_METHOD_DESCRIPTOR_NOARGS) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             assert(oparg == 0 || oparg == 1);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
@@ -3479,7 +3474,7 @@
         }
 
         TARGET(CALL_NO_KW_METHOD_DESCRIPTOR_FAST) {
-            assert(call_shape.kwnames == NULL);
+            assert(kwnames == NULL);
             int is_meth = is_method(stack_pointer, oparg);
             int total_args = oparg + is_meth;
             PyMethodDescrObject *callable =
@@ -3597,25 +3592,12 @@
             gen->gi_frame_state = FRAME_CREATED;
             gen_frame->owner = FRAME_OWNED_BY_GENERATOR;
             _Py_LeaveRecursiveCallPy(tstate);
-            if (!frame->is_entry) {
-                _PyInterpreterFrame *prev = frame->previous;
-                _PyThreadState_PopFrame(tstate, frame);
-                frame = cframe.current_frame = prev;
-                _PyFrame_StackPush(frame, (PyObject *)gen);
-                goto resume_frame;
-            }
-            _Py_LeaveRecursiveCallTstate(tstate);
-            /* Make sure that frame is in a valid state */
-            frame->stacktop = 0;
-            frame->f_locals = NULL;
-            Py_INCREF(frame->f_funcobj);
-            Py_INCREF(frame->f_code);
-            /* Restore previous cframe and return. */
-            tstate->cframe = cframe.previous;
-            tstate->cframe->use_tracing = cframe.use_tracing;
-            assert(tstate->cframe->current_frame == frame->previous);
-            assert(!_PyErr_Occurred(tstate));
-            return (PyObject *)gen;
+            assert(frame != &entry_frame);
+            _PyInterpreterFrame *prev = frame->previous;
+            _PyThreadState_PopFrame(tstate, frame);
+            frame = cframe.current_frame = prev;
+            _PyFrame_StackPush(frame, (PyObject *)gen);
+            goto resume_frame;
         }
 
         TARGET(BUILD_SLICE) {
diff --git a/Python/opcode_targets.h b/Python/opcode_targets.h
index 0603b44..237d3b9 100644
--- a/Python/opcode_targets.h
+++ b/Python/opcode_targets.h
@@ -2,19 +2,20 @@ static void *opcode_targets[256] = {
     &&TARGET_CACHE,
     &&TARGET_POP_TOP,
     &&TARGET_PUSH_NULL,
-    &&TARGET_BINARY_OP_ADD_FLOAT,
+    &&TARGET_INTERPRETER_EXIT,
     &&TARGET_END_FOR,
+    &&TARGET_BINARY_OP_ADD_FLOAT,
     &&TARGET_BINARY_OP_ADD_INT,
     &&TARGET_BINARY_OP_ADD_UNICODE,
     &&TARGET_BINARY_OP_GENERIC,
-    &&TARGET_BINARY_OP_INPLACE_ADD_UNICODE,
     &&TARGET_NOP,
     &&TARGET_UNARY_POSITIVE,
     &&TARGET_UNARY_NEGATIVE,
     &&TARGET_UNARY_NOT,
+    &&TARGET_BINARY_OP_INPLACE_ADD_UNICODE,
     &&TARGET_BINARY_OP_MULTIPLY_FLOAT,
-    &&TARGET_BINARY_OP_MULTIPLY_INT,
     &&TARGET_UNARY_INVERT,
+    &&TARGET_BINARY_OP_MULTIPLY_INT,
     &&TARGET_BINARY_OP_SUBTRACT_FLOAT,
     &&TARGET_BINARY_OP_SUBTRACT_INT,
     &&TARGET_BINARY_SUBSCR_DICT,
@@ -23,20 +24,20 @@ static void *opcode_targets[256] = {
     &&TARGET_BINARY_SUBSCR_TUPLE_INT,
     &&TARGET_CALL_PY_EXACT_ARGS,
     &&TARGET_CALL_PY_WITH_DEFAULTS,
-    &&TARGET_CALL_BOUND_METHOD_EXACT_ARGS,
     &&TARGET_BINARY_SUBSCR,
     &&TARGET_BINARY_SLICE,
     &&TARGET_STORE_SLICE,
+    &&TARGET_CALL_BOUND_METHOD_EXACT_ARGS,
     &&TARGET_CALL_BUILTIN_CLASS,
-    &&TARGET_CALL_BUILTIN_FAST_WITH_KEYWORDS,
     &&TARGET_GET_LEN,
     &&TARGET_MATCH_MAPPING,
     &&TARGET_MATCH_SEQUENCE,
     &&TARGET_MATCH_KEYS,
-    &&TARGET_CALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS,
+    &&TARGET_CALL_BUILTIN_FAST_WITH_KEYWORDS,
     &&TARGET_PUSH_EXC_INFO,
     &&TARGET_CHECK_EXC_MATCH,
     &&TARGET_CHECK_EG_MATCH,
+    &&TARGET_CALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS,
     &&TARGET_CALL_NO_KW_BUILTIN_FAST,
     &&TARGET_CALL_NO_KW_BUILTIN_O,
     &&TARGET_CALL_NO_KW_ISINSTANCE,
@@ -47,7 +48,6 @@ static void *opcode_targets[256] = {
     &&TARGET_CALL_NO_KW_METHOD_DESCRIPTOR_O,
     &&TARGET_CALL_NO_KW_STR_1,
     &&TARGET_CALL_NO_KW_TUPLE_1,
-    &&TARGET_CALL_NO_KW_TYPE_1,
     &&TARGET_WITH_EXCEPT_START,
     &&TARGET_GET_AITER,
     &&TARGET_GET_ANEXT,
@@ -55,37 +55,37 @@ static void *opcode_targets[256] = {
     &&TARGET_BEFORE_WITH,
     &&TARGET_END_ASYNC_FOR,
     &&TARGET_CLEANUP_THROW,
+    &&TARGET_CALL_NO_KW_TYPE_1,
     &&TARGET_COMPARE_OP_FLOAT_JUMP,
     &&TARGET_COMPARE_OP_GENERIC,
     &&TARGET_COMPARE_OP_INT_JUMP,
-    &&TARGET_COMPARE_OP_STR_JUMP,
     &&TARGET_STORE_SUBSCR,
     &&TARGET_DELETE_SUBSCR,
-    &&TARGET_FOR_ITER_LIST,
+    &&TARGET_COMPARE_OP_STR_JUMP,
     &&TARGET_STOPITERATION_ERROR,
+    &&TARGET_FOR_ITER_LIST,
     &&TARGET_FOR_ITER_RANGE,
     &&TARGET_FOR_ITER_GEN,
     &&TARGET_LOAD_ATTR_CLASS,
-    &&TARGET_LOAD_ATTR_GETATTRIBUTE_OVERRIDDEN,
     &&TARGET_GET_ITER,
     &&TARGET_GET_YIELD_FROM_ITER,
     &&TARGET_PRINT_EXPR,
     &&TARGET_LOAD_BUILD_CLASS,
+    &&TARGET_LOAD_ATTR_GETATTRIBUTE_OVERRIDDEN,
     &&TARGET_LOAD_ATTR_INSTANCE_VALUE,
-    &&TARGET_LOAD_ATTR_MODULE,
     &&TARGET_LOAD_ASSERTION_ERROR,
     &&TARGET_RETURN_GENERATOR,
+    &&TARGET_LOAD_ATTR_MODULE,
     &&TARGET_LOAD_ATTR_PROPERTY,
     &&TARGET_LOAD_ATTR_SLOT,
     &&TARGET_LOAD_ATTR_WITH_HINT,
     &&TARGET_LOAD_ATTR_METHOD_LAZY_DICT,
     &&TARGET_LOAD_ATTR_METHOD_NO_DICT,
-    &&TARGET_LOAD_ATTR_METHOD_WITH_DICT,
     &&TARGET_LIST_TO_TUPLE,
     &&TARGET_RETURN_VALUE,
     &&TARGET_IMPORT_STAR,
     &&TARGET_SETUP_ANNOTATIONS,
-    &&TARGET_LOAD_ATTR_METHOD_WITH_VALUES,
+    &&TARGET_LOAD_ATTR_METHOD_WITH_DICT,
     &&TARGET_ASYNC_GEN_WRAP,
     &&TARGET_PREP_RERAISE_STAR,
     &&TARGET_POP_EXCEPT,
@@ -112,7 +112,7 @@ static void *opcode_targets[256] = {
     &&TARGET_JUMP_FORWARD,
     &&TARGET_JUMP_IF_FALSE_OR_POP,
     &&TARGET_JUMP_IF_TRUE_OR_POP,
-    &&TARGET_LOAD_CONST__LOAD_FAST,
+    &&TARGET_LOAD_ATTR_METHOD_WITH_VALUES,
     &&TARGET_POP_JUMP_IF_FALSE,
     &&TARGET_POP_JUMP_IF_TRUE,
     &&TARGET_LOAD_GLOBAL,
@@ -120,7 +120,7 @@ static void *opcode_targets[256] = {
     &&TARGET_CONTAINS_OP,
     &&TARGET_RERAISE,
     &&TARGET_COPY,
-    &&TARGET_LOAD_FAST__LOAD_CONST,
+    &&TARGET_LOAD_CONST__LOAD_FAST,
     &&TARGET_BINARY_OP,
     &&TARGET_SEND,
     &&TARGET_LOAD_FAST,
@@ -140,9 +140,9 @@ static void *opcode_targets[256] = {
     &&TARGET_STORE_DEREF,
     &&TARGET_DELETE_DEREF,
     &&TARGET_JUMP_BACKWARD,
-    &&TARGET_LOAD_FAST__LOAD_FAST,
+    &&TARGET_LOAD_FAST__LOAD_CONST,
     &&TARGET_CALL_FUNCTION_EX,
-    &&TARGET_LOAD_GLOBAL_BUILTIN,
+    &&TARGET_LOAD_FAST__LOAD_FAST,
     &&TARGET_EXTENDED_ARG,
     &&TARGET_LIST_APPEND,
     &&TARGET_SET_ADD,
@@ -152,27 +152,27 @@ static void *opcode_targets[256] = {
     &&TARGET_YIELD_VALUE,
     &&TARGET_RESUME,
     &&TARGET_MATCH_CLASS,
+    &&TARGET_LOAD_GLOBAL_BUILTIN,
     &&TARGET_LOAD_GLOBAL_MODULE,
-    &&TARGET_STORE_ATTR_INSTANCE_VALUE,
     &&TARGET_FORMAT_VALUE,
     &&TARGET_BUILD_CONST_KEY_MAP,
     &&TARGET_BUILD_STRING,
+    &&TARGET_STORE_ATTR_INSTANCE_VALUE,
     &&TARGET_STORE_ATTR_SLOT,
     &&TARGET_STORE_ATTR_WITH_HINT,
     &&TARGET_STORE_FAST__LOAD_FAST,
-    &&TARGET_STORE_FAST__STORE_FAST,
     &&TARGET_LIST_EXTEND,
     &&TARGET_SET_UPDATE,
     &&TARGET_DICT_MERGE,
     &&TARGET_DICT_UPDATE,
+    &&TARGET_STORE_FAST__STORE_FAST,
     &&TARGET_STORE_SUBSCR_DICT,
     &&TARGET_STORE_SUBSCR_LIST_INT,
     &&TARGET_UNPACK_SEQUENCE_LIST,
     &&TARGET_UNPACK_SEQUENCE_TUPLE,
-    &&TARGET_UNPACK_SEQUENCE_TWO_TUPLE,
     &&TARGET_CALL,
     &&TARGET_KW_NAMES,
-    &&_unknown_opcode,
+    &&TARGET_UNPACK_SEQUENCE_TWO_TUPLE,
     &&_unknown_opcode,
     &&_unknown_opcode,
     &&_unknown_opcode,
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 51192bd..1351976 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -29,6 +29,7 @@
 #include "pycore_tuple.h"         // _PyTuple_InitTypes()
 #include "pycore_typeobject.h"    // _PyTypes_InitTypes()
 #include "pycore_unicodeobject.h" // _PyUnicode_InitTypes()
+#include "opcode.h"
 
 extern void _PyIO_Fini(void);
 
@@ -779,6 +780,21 @@ pycore_init_types(PyInterpreterState *interp)
     return _PyStatus_OK();
 }
 
+static const uint8_t INTERPRETER_TRAMPOLINE_INSTRUCTIONS[] = {
+    /* Put a NOP at the start, so that the IP points into
+    * the code, rather than before it */
+    NOP, 0,
+    INTERPRETER_EXIT, 0,
+    /* RESUME at end makes sure that the frame appears incomplete */
+    RESUME, 0
+};
+
+static const _PyShimCodeDef INTERPRETER_TRAMPOLINE_CODEDEF = {
+    INTERPRETER_TRAMPOLINE_INSTRUCTIONS,
+    sizeof(INTERPRETER_TRAMPOLINE_INSTRUCTIONS),
+    1,
+    "<interpreter trampoline>"
+};
 
 static PyStatus
 pycore_init_builtins(PyThreadState *tstate)
@@ -812,7 +828,10 @@ pycore_init_builtins(PyThreadState *tstate)
     PyObject *object__getattribute__ = _PyType_Lookup(&PyBaseObject_Type, &_Py_ID(__getattribute__));
     assert(object__getattribute__);
     interp->callable_cache.object__getattribute__ = object__getattribute__;
-
+    interp->interpreter_trampoline = _Py_MakeShimCode(&INTERPRETER_TRAMPOLINE_CODEDEF);
+    if (interp->interpreter_trampoline == NULL) {
+        return _PyStatus_ERR("failed to create interpreter trampoline.");
+    }
     if (_PyBuiltins_AddExceptions(bimod) < 0) {
         return _PyStatus_ERR("failed to add exceptions to builtins");
     }
diff --git a/Python/pystate.c b/Python/pystate.c
index b5fd8c2..04db1fb4 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -454,6 +454,7 @@ interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
     PyDict_Clear(interp->builtins);
     Py_CLEAR(interp->sysdict);
     Py_CLEAR(interp->builtins);
+    Py_CLEAR(interp->interpreter_trampoline);
 
     for (int i=0; i < DICT_MAX_WATCHERS; i++) {
         interp->dict_watchers[i] = NULL;
diff --git a/Python/traceback.c b/Python/traceback.c
index 2d9da0e..aacdb33 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -1224,6 +1224,15 @@ dump_traceback(int fd, PyThreadState *tstate, int write_header)
         if (frame == NULL) {
             break;
         }
+        if (frame->owner == FRAME_OWNED_BY_CSTACK) {
+            /* Trampoline frame */
+            frame = frame->previous;
+        }
+        if (frame == NULL) {
+            break;
+        }
+        /* Can't have more than one shim frame in a row */
+        assert(frame->owner != FRAME_OWNED_BY_CSTACK);
         depth++;
     }
 }