GH-87849: Simplify stack effect of SEND and specialize it for generators and coroutines. (GH-101788)

1 files changed, 52 insertions, 37 deletions

diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index a224d4e..093ebff 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -882,57 +882,69 @@
         }
 
         TARGET(SEND) {
+            PREDICTED(SEND);
             PyObject *v = PEEK(1);
             PyObject *receiver = PEEK(2);
             PyObject *retval;
+            #if ENABLE_SPECIALIZATION
+            _PySendCache *cache = (_PySendCache *)next_instr;
+            if (ADAPTIVE_COUNTER_IS_ZERO(cache->counter)) {
+                assert(cframe.use_tracing == 0);
+                next_instr--;
+                _Py_Specialize_Send(receiver, next_instr);
+                DISPATCH_SAME_OPARG();
+            }
+            STAT_INC(SEND, deferred);
+            DECREMENT_ADAPTIVE_COUNTER(cache->counter);
+            #endif  /* ENABLE_SPECIALIZATION */
             assert(frame != &entry_frame);
-            bool jump = false;
-            PySendResult gen_status;
-            if (tstate->c_tracefunc == NULL) {
-                gen_status = PyIter_Send(receiver, v, &retval);
-            } else {
-                if (Py_IsNone(v) && PyIter_Check(receiver)) {
-                    retval = Py_TYPE(receiver)->tp_iternext(receiver);
-                }
-                else {
-                    retval = PyObject_CallMethodOneArg(receiver, &_Py_ID(send), v);
-                }
-                if (retval == NULL) {
-                    if (tstate->c_tracefunc != NULL
-                            && _PyErr_ExceptionMatches(tstate, PyExc_StopIteration))
-                        call_exc_trace(tstate->c_tracefunc, tstate->c_traceobj, tstate, frame);
-                    if (_PyGen_FetchStopIterationValue(&retval) == 0) {
-                        gen_status = PYGEN_RETURN;
-                    }
-                    else {
-                        gen_status = PYGEN_ERROR;
-                    }
+            if (Py_IsNone(v) && PyIter_Check(receiver)) {
+                retval = Py_TYPE(receiver)->tp_iternext(receiver);
+            }
+            else {
+                retval = PyObject_CallMethodOneArg(receiver, &_Py_ID(send), v);
+            }
+            if (retval == NULL) {
+                if (tstate->c_tracefunc != NULL
+                        && _PyErr_ExceptionMatches(tstate, PyExc_StopIteration))
+                    call_exc_trace(tstate->c_tracefunc, tstate->c_traceobj, tstate, frame);
+                if (_PyGen_FetchStopIterationValue(&retval) == 0) {
+                    assert(retval != NULL);
+                    JUMPBY(oparg);
                 }
                 else {
-                    gen_status = PYGEN_NEXT;
+                    assert(retval == NULL);
+                    goto error;
                 }
             }
-            if (gen_status == PYGEN_ERROR) {
-                assert(retval == NULL);
-                goto error;
-            }
-            Py_DECREF(v);
-            if (gen_status == PYGEN_RETURN) {
-                assert(retval != NULL);
-                Py_DECREF(receiver);
-                JUMPBY(oparg);
-                jump = true;
-            }
             else {
-                assert(gen_status == PYGEN_NEXT);
                 assert(retval != NULL);
             }
-            STACK_SHRINK(1);
-            STACK_GROW(((!jump) ? 1 : 0));
             POKE(1, retval);
+            JUMPBY(1);
             DISPATCH();
         }
 
+        TARGET(SEND_GEN) {
+            PyObject *v = PEEK(1);
+            PyObject *receiver = PEEK(2);
+            assert(cframe.use_tracing == 0);
+            PyGenObject *gen = (PyGenObject *)receiver;
+            DEOPT_IF(Py_TYPE(gen) != &PyGen_Type &&
+                     Py_TYPE(gen) != &PyCoro_Type, SEND);
+            DEOPT_IF(gen->gi_frame_state >= FRAME_EXECUTING, SEND);
+            STAT_INC(SEND, hit);
+            _PyInterpreterFrame *gen_frame = (_PyInterpreterFrame *)gen->gi_iframe;
+            frame->yield_offset = oparg;
+            STACK_SHRINK(1);
+            _PyFrame_StackPush(gen_frame, v);
+            gen->gi_frame_state = FRAME_EXECUTING;
+            gen->gi_exc_state.previous_item = tstate->exc_info;
+            tstate->exc_info = &gen->gi_exc_state;
+            JUMPBY(INLINE_CACHE_ENTRIES_SEND + oparg);
+            DISPATCH_INLINED(gen_frame);
+        }
+
         TARGET(YIELD_VALUE) {
             PyObject *retval = PEEK(1);
             // NOTE: It's important that YIELD_VALUE never raises an exception!
@@ -1026,6 +1038,7 @@
             PyObject *exc_value = PEEK(1);
             PyObject *last_sent_val = PEEK(2);
             PyObject *sub_iter = PEEK(3);
+            PyObject *none;
             PyObject *value;
             assert(throwflag);
             assert(exc_value && PyExceptionInstance_Check(exc_value));
@@ -1034,13 +1047,15 @@
                 Py_DECREF(sub_iter);
                 Py_DECREF(last_sent_val);
                 Py_DECREF(exc_value);
+                none = Py_NewRef(Py_None);
             }
             else {
                 _PyErr_SetRaisedException(tstate, Py_NewRef(exc_value));
                 goto exception_unwind;
             }
-            STACK_SHRINK(2);
+            STACK_SHRINK(1);
             POKE(1, value);
+            POKE(2, none);
             DISPATCH();
         }