Address review comments

Author: markshannon

Python/bytecodes.c

@@ -2924,7 +2924,6 @@ dummy_func(
                 else {
                     this_instr[1].counter = initial_jump_backoff_counter();
                     assert(tstate->current_executor == NULL);
-                    tstate->current_executor = (PyObject *)executor;
                     GOTO_TIER_TWO(executor);
                 }
             }
@@ -2989,7 +2988,6 @@ dummy_func(
                 }
                 DISPATCH_GOTO();
             }
-            tstate->current_executor = (PyObject *)executor;
             GOTO_TIER_TWO(executor);
             #else
             Py_FatalError("ENTER_EXECUTOR is not supported in this build");
@@ -5264,7 +5262,6 @@ dummy_func(
                 exit->temperature = initial_temperature_backoff_counter();
                 Py_CLEAR(exit->executor);
             }
-            tstate->current_executor = NULL;
             if (exit->executor == NULL) {
                 _Py_BackoffCounter temperature = exit->temperature;
                 if (!backoff_counter_triggers(temperature)) {
@@ -5287,7 +5284,6 @@ dummy_func(
                 }
                 exit->executor = executor;
             }
-            tstate->current_executor = (PyObject *)exit->executor;
             GOTO_TIER_TWO(exit->executor);
         }
 
@@ -5346,12 +5342,10 @@ dummy_func(
         }
 
         tier2 op(_DEOPT, (--)) {
-            tstate->current_executor = NULL;
             GOTO_TIER_ONE(_PyFrame_GetBytecode(frame) + CURRENT_TARGET());
         }
 
         tier2 op(_ERROR_POP_N, (target/2 --)) {
-            tstate->current_executor = NULL;
             assert(oparg == 0);
             frame->instr_ptr = _PyFrame_GetBytecode(frame) + target;
             SYNC_SP();

Python/ceval_macros.h

@@ -359,7 +359,7 @@ _PyFrame_SetStackPointer(frame, stack_pointer)
 do {                                                   \
     OPT_STAT_INC(traces_executed);                     \
     _PyExecutorObject *_executor = (EXECUTOR);         \
-    assert(tstate->current_executor == _executor);     \
+    tstate->current_executor = (PyObject *)_executor;  \
     jit_func jitted = _executor->jit_code;             \
     /* Keep the shim frame alive via the executor: */  \
     Py_INCREF(_executor);                              \
@@ -378,7 +378,9 @@ do {                                                   \
 #define GOTO_TIER_TWO(EXECUTOR) \
 do { \
     OPT_STAT_INC(traces_executed); \
-    next_uop = (EXECUTOR)->trace; \
+    _PyExecutorObject *_executor = (EXECUTOR); \
+    tstate->current_executor = (PyObject *)_executor; \
+    next_uop = _executor->trace; \
     assert(next_uop->opcode == _START_EXECUTOR); \
     goto enter_tier_two; \
 } while (0)
@@ -387,6 +389,7 @@ do { \
 #define GOTO_TIER_ONE(TARGET)                                         \
     do                                                                \
     {                                                                 \
+        tstate->current_executor = NULL;                              \
         next_instr = (TARGET);                                        \
         assert(tstate->current_executor == NULL);                     \
         OPT_HIST(trace_uop_execution_counter, trace_run_length_hist); \

Python/executor_cases.c.h

@@ -224,6 +224,8 @@ _Py_ClearExecutorDeletionList(PyInterpreterState *interp)
     while (ts) {
         _PyExecutorObject *current = (_PyExecutorObject *)ts->current_executor;
         if (current != NULL) {
+            /* Anything in this list will be unlinked, so we can reuse the
+             * linked field as a reachability marker. */
             current->vm_data.linked = 1;
         }
         HEAD_LOCK(runtime);

Python/generated_cases.c.h

@@ -50,13 +50,16 @@
 #define GOTO_TIER_TWO(EXECUTOR)                                            \
 do {                                                                       \
     OPT_STAT_INC(traces_executed);                                         \
-    jit_func_preserve_none jitted = (EXECUTOR)->jit_side_entry;            \
+    _PyExecutorObject *_executor = (EXECUTOR);                             \
+    tstate->current_executor = (PyObject *)_executor;                      \
+    jit_func_preserve_none jitted = _executor->jit_side_entry;             \
     __attribute__((musttail)) return jitted(frame, stack_pointer, tstate); \
 } while (0)
 
 #undef GOTO_TIER_ONE
 #define GOTO_TIER_ONE(TARGET)                       \
 do {                                                \
+    tstate->current_executor = NULL;                \
     _PyFrame_SetStackPointer(frame, stack_pointer); \
     return TARGET;                                  \
 } while (0)