Tier 2 TOS caching, working for interpreter.

Author: markshannon

Include/internal/pycore_uop_ids.h

@@ -5328,6 +5328,7 @@ dummy_func(
         }
 
         tier2 op(_DEOPT, (--)) {
+            SYNC_SP();
             GOTO_TIER_ONE(_PyFrame_GetBytecode(frame) + CURRENT_TARGET());
         }
 

Include/internal/pycore_uop_metadata.h

@@ -164,13 +164,26 @@ dump_item(_PyStackRef item)
         printf("%" PRId64, (int64_t)PyStackRef_UntagInt(item));
         return;
     }
-    PyObject *obj = PyStackRef_AsPyObjectBorrow(item);
-    if (obj == NULL) {
-        printf("<nil>");
-        return;
+    if (PyStackRef_IsValid(item)) {
+        PyObject *obj = PyStackRef_AsPyObjectBorrow(item);
+        if (obj == NULL) {
+            printf("<nil>");
+            return;
+        }
+        // Don't call __repr__(), it might recurse into the interpreter.
+        printf("<%s at %p>", Py_TYPE(obj)->tp_name, (void *)obj);
+    }
+    else {
+        /* Already handled NULL */
+        if (PyStackRef_IsError(item)) {
+            printf("ERROR");
+        }
+        else {
+            // Wrapped item
+            void *ptr = PyStackRef_Unwrap(item);
+            printf("Wrapped(pointer %p)", ptr);
+        }
     }
-    // Don't call __repr__(), it might recurse into the interpreter.
-    printf("<%s at %p>", Py_TYPE(obj)->tp_name, (void *)obj);
 }
 
 static void