GH-89914: Make the oparg of the YIELD_VALUE instruction equal the stack depth. (GH-92960)

Author: markshannon

Doc/library/dis.rst

@@ -575,6 +575,8 @@ iterations of the loop.
 
    Pops TOS and yields it from a :term:`generator`.
 
+    .. versionchanged:: 3.11
+       oparg set to be the stack depth, for efficient handling on frames.
 
 .. opcode:: YIELD_FROM
 

Include/internal/pycore_opcode.h

@@ -405,6 +405,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.11a7 3494 (New location info table)
 
 #     Python 3.12a1 3500 (Remove PRECALL opcode)
+#     Python 3.12a1 3501 (YIELD_VALUE oparg == stack_depth)
 
 #     Python 3.13 will start with 3550
 
@@ -418,7 +419,7 @@ 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 = (3500).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3501).to_bytes(2, 'little') + b'\r\n'
 
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 

Include/opcode.h

@@ -98,7 +98,7 @@ def jabs_op(name, op):
 def_op('RETURN_VALUE', 83)
 def_op('IMPORT_STAR', 84)
 def_op('SETUP_ANNOTATIONS', 85)
-def_op('YIELD_VALUE', 86)
+
 def_op('ASYNC_GEN_WRAP', 87)
 def_op('PREP_RERAISE_STAR', 88)
 def_op('POP_EXCEPT', 89)
@@ -174,7 +174,7 @@ def jabs_op(name, op):
 def_op('LOAD_CLASSDEREF', 148)
 hasfree.append(148)
 def_op('COPY_FREE_VARS', 149)
-
+def_op('YIELD_VALUE', 150)
 def_op('RESUME', 151)
 def_op('MATCH_CLASS', 152)
 

Lib/importlib/_bootstrap_external.py

@@ -0,0 +1,2 @@
+The operand of the ``YIELD_VALUE`` instruction is set to the stack depth.
+This is done to help frame handling on ``yield`` and may assist debuggers.

Lib/opcode.py

@@ -2698,6 +2698,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
         }
 
         TARGET(YIELD_VALUE) {
+            assert(oparg == STACK_LEVEL());
             assert(frame->is_entry);
             PyObject *retval = POP();
             _PyFrame_GetGenerator(frame)->gi_frame_state = FRAME_SUSPENDED;

Misc/NEWS.d/next/Core and Builtins/2022-05-19-15-29-53.gh-issue-89914.8bAffH.rst

@@ -1962,7 +1962,7 @@ compiler_add_yield_from(struct compiler *c, int await)
     compiler_use_next_block(c, start);
     ADDOP_JUMP(c, SEND, exit);
     compiler_use_next_block(c, resume);
-    ADDOP(c, YIELD_VALUE);
+    ADDOP_I(c, YIELD_VALUE, 0);
     ADDOP_I(c, RESUME, await ? 3 : 2);
     ADDOP_JUMP(c, JUMP_NO_INTERRUPT, start);
     compiler_use_next_block(c, exit);
@@ -4193,7 +4193,7 @@ addop_yield(struct compiler *c) {
     if (c->u->u_ste->ste_generator && c->u->u_ste->ste_coroutine) {
         ADDOP(c, ASYNC_GEN_WRAP);
     }
-    ADDOP(c, YIELD_VALUE);
+    ADDOP_I(c, YIELD_VALUE, 0);
     ADDOP_I(c, RESUME, 1);
     return 1;
 }
@@ -7152,6 +7152,9 @@ stackdepth(struct compiler *c, basicblock *entry)
                 next = NULL;
                 break;
             }
+            if (instr->i_opcode == YIELD_VALUE) {
+                instr->i_oparg = depth;
+            }
         }
         if (next != NULL) {
             assert(b->b_nofallthrough == 0);