bpo-46528: Simplify the VM's stack manipulations (GH-30902)

1 files changed, 9 insertions, 59 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 29ca5e3..106e408 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1434,8 +1434,6 @@ eval_frame_handle_pending(PyThreadState *tstate)
 #define PEEK(n)           (stack_pointer[-(n)])
 #define SET_TOP(v)        (stack_pointer[-1] = (v))
 #define SET_SECOND(v)     (stack_pointer[-2] = (v))
-#define SET_THIRD(v)      (stack_pointer[-3] = (v))
-#define SET_FOURTH(v)     (stack_pointer[-4] = (v))
 #define BASIC_STACKADJ(n) (stack_pointer += n)
 #define BASIC_PUSH(v)     (*stack_pointer++ = (v))
 #define BASIC_POP()       (*--stack_pointer)
@@ -1920,54 +1918,6 @@ handle_eval_breaker:
             DISPATCH();
         }
 
-        TARGET(ROT_TWO) {
-            PyObject *top = TOP();
-            PyObject *second = SECOND();
-            SET_TOP(second);
-            SET_SECOND(top);
-            DISPATCH();
-        }
-
-        TARGET(ROT_THREE) {
-            PyObject *top = TOP();
-            PyObject *second = SECOND();
-            PyObject *third = THIRD();
-            SET_TOP(second);
-            SET_SECOND(third);
-            SET_THIRD(top);
-            DISPATCH();
-        }
-
-        TARGET(ROT_FOUR) {
-            PyObject *top = TOP();
-            PyObject *second = SECOND();
-            PyObject *third = THIRD();
-            PyObject *fourth = FOURTH();
-            SET_TOP(second);
-            SET_SECOND(third);
-            SET_THIRD(fourth);
-            SET_FOURTH(top);
-            DISPATCH();
-        }
-
-        TARGET(DUP_TOP) {
-            PyObject *top = TOP();
-            Py_INCREF(top);
-            PUSH(top);
-            DISPATCH();
-        }
-
-        TARGET(DUP_TOP_TWO) {
-            PyObject *top = TOP();
-            PyObject *second = SECOND();
-            Py_INCREF(top);
-            Py_INCREF(second);
-            STACK_GROW(2);
-            SET_TOP(top);
-            SET_SECOND(second);
-            DISPATCH();
-        }
-
         TARGET(UNARY_POSITIVE) {
             PyObject *value = TOP();
             PyObject *res = PyNumber_Positive(value);
@@ -5170,14 +5120,6 @@ handle_eval_breaker:
             DISPATCH();
         }
 
-        TARGET(ROT_N) {
-            PyObject *top = TOP();
-            memmove(&PEEK(oparg - 1), &PEEK(oparg),
-                    sizeof(PyObject*) * (oparg - 1));
-            PEEK(oparg) = top;
-            DISPATCH();
-        }
-
         TARGET(COPY) {
             assert(oparg != 0);
             PyObject *peek = PEEK(oparg);
@@ -5221,6 +5163,14 @@ handle_eval_breaker:
             }
         }
 
+        TARGET(SWAP) {
+            assert(oparg != 0);
+            PyObject *top = TOP();
+            SET_TOP(PEEK(oparg));
+            PEEK(oparg) = top;
+            DISPATCH();
+        }
+
         TARGET(EXTENDED_ARG) {
             int oldoparg = oparg;
             NEXTOPARG();
@@ -7380,7 +7330,7 @@ format_awaitable_error(PyThreadState *tstate, PyTypeObject *type, int prevprevop
                           "that does not implement __await__: %.100s",
                           type->tp_name);
         }
-        else if (prevopcode == WITH_EXCEPT_START || (prevopcode == CALL_NO_KW && prevprevopcode == DUP_TOP)) {
+        else if (prevopcode == WITH_EXCEPT_START || (prevopcode == CALL_NO_KW && prevprevopcode == LOAD_CONST)) {
             _PyErr_Format(tstate, PyExc_TypeError,
                           "'async with' received an object from __aexit__ "
                           "that does not implement __await__: %.100s",