Leave receiver on stack when exiting SEND loop.

Lib/importlib/_bootstrap_external.py

@@ -432,6 +432,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.12a5 3516 (Add COMPARE_AND_BRANCH instruction)
 #     Python 3.12a5 3517 (Change YIELD_VALUE oparg to exception block depth)
 #     Python 3.12a5 3518 (Add RETURN_CONST instruction)
+#     Python 3.12a5 3519 (Modify SEND instruction)
 
 #     Python 3.13 will start with 3550
 
@@ -444,7 +445,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3518).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3519).to_bytes(2, 'little') + b'\r\n'
 
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 

Lib/test/test_dis.py

@@ -479,7 +479,9 @@ async def _asyncwith(c):
            YIELD_VALUE              2
            RESUME                   3
            JUMP_BACKWARD_NO_INTERRUPT     4 (to 14)
-        >> POP_TOP
+        >> SWAP                     2
+           POP_TOP
+           POP_TOP
 
 %3d        LOAD_CONST               1 (1)
            STORE_FAST               1 (x)
@@ -490,30 +492,33 @@ async def _asyncwith(c):
            CALL                     2
            GET_AWAITABLE            2
            LOAD_CONST               0 (None)
-        >> SEND                     3 (to 56)
+        >> SEND                     3 (to 60)
            YIELD_VALUE              2
            RESUME                   3
-           JUMP_BACKWARD_NO_INTERRUPT     4 (to 48)
+           JUMP_BACKWARD_NO_INTERRUPT     4 (to 52)
         >> POP_TOP
+           POP_TOP
 
 %3d        LOAD_CONST               2 (2)
            STORE_FAST               2 (y)
            RETURN_CONST             0 (None)
 
 %3d     >> CLEANUP_THROW
-           JUMP_BACKWARD           23 (to 22)
+           JUMP_BACKWARD           26 (to 22)
         >> CLEANUP_THROW
-           JUMP_BACKWARD            8 (to 56)
+           JUMP_BACKWARD            9 (to 60)
         >> PUSH_EXC_INFO
            WITH_EXCEPT_START
            GET_AWAITABLE            2
            LOAD_CONST               0 (None)
-        >> SEND                     4 (to 90)
+        >> SEND                     4 (to 96)
            YIELD_VALUE              3
            RESUME                   3
-           JUMP_BACKWARD_NO_INTERRUPT     4 (to 80)
+           JUMP_BACKWARD_NO_INTERRUPT     4 (to 86)
         >> CLEANUP_THROW
-        >> POP_JUMP_IF_TRUE         1 (to 94)
+        >> SWAP                     2
+           POP_TOP
+           POP_JUMP_IF_TRUE         1 (to 104)
            RERAISE                  2
         >> POP_TOP
            POP_EXCEPT

Objects/frameobject.c

@@ -336,8 +336,8 @@ mark_stacks(PyCodeObject *code_obj, int len)
                 case SEND:
                     j = get_arg(code, i) + i + 1;
                     assert(j < len);
-                    assert(stacks[j] == UNINITIALIZED || stacks[j] == pop_value(next_stack));
-                    stacks[j] = pop_value(next_stack);
+                    assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
+                    stacks[j] = next_stack;
                     stacks[i+1] = next_stack;
                     break;
                 case JUMP_FORWARD:

Python/bytecodes.c

@@ -680,9 +680,8 @@ dummy_func(
             PREDICT(LOAD_CONST);
         }
 
-        inst(SEND, (receiver, v -- receiver if (!jump), retval)) {
+        inst(SEND, (receiver, v -- receiver, retval)) {
             assert(frame != &entry_frame);
-            bool jump = false;
             PySendResult gen_status;
             if (tstate->c_tracefunc == NULL) {
                 gen_status = PyIter_Send(receiver, v, &retval);
@@ -715,9 +714,7 @@ dummy_func(
             Py_DECREF(v);
             if (gen_status == PYGEN_RETURN) {
                 assert(retval != NULL);
-                Py_DECREF(receiver);
                 JUMPBY(oparg);
-                jump = true;
             }
             else {
                 assert(gen_status == PYGEN_NEXT);
@@ -796,12 +793,13 @@ dummy_func(
             }
         }
 
-        inst(CLEANUP_THROW, (sub_iter, last_sent_val, exc_value -- value)) {
+        inst(CLEANUP_THROW, (sub_iter, last_sent_val, exc_value -- none, value)) {
             assert(throwflag);
             assert(exc_value && PyExceptionInstance_Check(exc_value));
             if (PyErr_GivenExceptionMatches(exc_value, PyExc_StopIteration)) {
                 value = Py_NewRef(((PyStopIterationObject *)exc_value)->value);
                 DECREF_INPUTS();
+                none = Py_NewRef(Py_None);
             }
             else {
                 _PyErr_SetRaisedException(tstate, Py_NewRef(exc_value));

Python/compile.c

@@ -1789,6 +1789,8 @@ compiler_add_yield_from(struct compiler *c, location loc, int await)
     ADDOP(c, loc, CLEANUP_THROW);
 
     USE_LABEL(c, exit);
+    ADDOP_I(c, loc, SWAP, 2);
+    ADDOP(c, loc, POP_TOP);
     return SUCCESS;
 }
 

Python/opcode_metadata.h

@@ -453,7 +453,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
         case GET_AWAITABLE:
             return 1;
         case SEND:
-            return ((!jump) ? 1 : 0) + 1;
+            return 2;
         case YIELD_VALUE:
             return 1;
         case POP_EXCEPT:
@@ -465,7 +465,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
         case END_ASYNC_FOR:
             return 0;
         case CLEANUP_THROW:
-            return 1;
+            return 2;
         case LOAD_ASSERTION_ERROR:
             return 1;
         case LOAD_BUILD_CLASS: