GH-112354: `END_FOR` instruction to only pop one value. (GH-114247)

* Compiler emits END_FOR; POP_TOP instead of END_FOR. To support tier 2 side exits in loops.

1 files changed, 10 insertions, 0 deletions

diff --git a/Python/compile.c b/Python/compile.c
index 2a6291c..7cf05dd 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -3075,7 +3075,12 @@ compiler_for(struct compiler *c, stmt_ty s)
     ADDOP_JUMP(c, NO_LOCATION, JUMP, start);
 
     USE_LABEL(c, cleanup);
+    /* It is important for instrumentation that the `END_FOR` comes first.
+    * Iteration over a generator will jump to the first of these instructions,
+    * but a non-generator will jump to a later instruction.
+    */
     ADDOP(c, NO_LOCATION, END_FOR);
+    ADDOP(c, NO_LOCATION, POP_TOP);
 
     compiler_pop_fblock(c, FOR_LOOP, start);
 
@@ -5390,7 +5395,12 @@ compiler_sync_comprehension_generator(struct compiler *c, location loc,
         ADDOP_JUMP(c, elt_loc, JUMP, start);
 
         USE_LABEL(c, anchor);
+        /* It is important for instrumentation that the `END_FOR` comes first.
+        * Iteration over a generator will jump to the first of these instructions,
+        * but a non-generator will jump to a later instruction.
+        */
         ADDOP(c, NO_LOCATION, END_FOR);
+        ADDOP(c, NO_LOCATION, POP_TOP);
     }
 
     return SUCCESS;