Modernize LOAD_ATTR_SLOT

Author: gvanrossum

Python/bytecodes.c

@@ -1443,7 +1443,7 @@ dummy_func(
             LOAD_ATTR_INSTANCE_VALUE,
             LOAD_ATTR_MODULE,
             // LOAD_ATTR_PROPERTY,
-            // LOAD_ATTR_SLOT,
+            LOAD_ATTR_SLOT,
             LOAD_ATTR_WITH_HINT,
             // LOAD_ATTR_METHOD_LAZY_DICT,
             // LOAD_ATTR_METHOD_NO_DICT,
@@ -1564,26 +1564,18 @@ dummy_func(
             Py_DECREF(owner);
         }
 
-        // error: LOAD_ATTR has irregular stack effect
-        inst(LOAD_ATTR_SLOT) {
+        inst(LOAD_ATTR_SLOT, (unused/1, type_version/2, index/1, unused/5, owner -- res2 if (oparg & 1), res)) {
             assert(cframe.use_tracing == 0);
-            PyObject *owner = TOP();
-            PyObject *res;
             PyTypeObject *tp = Py_TYPE(owner);
-            _PyAttrCache *cache = (_PyAttrCache *)next_instr;
-            uint32_t type_version = read_u32(cache->version);
             assert(type_version != 0);
             DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
-            char *addr = (char *)owner + cache->index;
+            char *addr = (char *)owner + index;
             res = *(PyObject **)addr;
             DEOPT_IF(res == NULL, LOAD_ATTR);
             STAT_INC(LOAD_ATTR, hit);
             Py_INCREF(res);
-            SET_TOP(NULL);
-            STACK_GROW((oparg & 1));
-            SET_TOP(res);
+            res2 = NULL;
             Py_DECREF(owner);
-            JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
         }
 
         // error: LOAD_ATTR has irregular stack effect

Python/generated_cases.c.h

@@ -193,7 +193,7 @@ _PyOpcode_num_popped(int opcode, int oparg) {
         case LOAD_ATTR_WITH_HINT:
             return 1;
         case LOAD_ATTR_SLOT:
-            return -1;
+            return 1;
         case LOAD_ATTR_CLASS:
             return -1;
         case LOAD_ATTR_PROPERTY:
@@ -539,7 +539,7 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
         case LOAD_ATTR_WITH_HINT:
             return ((oparg & 1) ? 1 : 0) + 1;
         case LOAD_ATTR_SLOT:
-            return -1;
+            return ((oparg & 1) ? 1 : 0) + 1;
         case LOAD_ATTR_CLASS:
             return -1;
         case LOAD_ATTR_PROPERTY:
@@ -795,7 +795,7 @@ struct opcode_metadata {
     [LOAD_ATTR_INSTANCE_VALUE] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
     [LOAD_ATTR_MODULE] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
     [LOAD_ATTR_WITH_HINT] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
-    [LOAD_ATTR_SLOT] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
+    [LOAD_ATTR_SLOT] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
     [LOAD_ATTR_CLASS] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [LOAD_ATTR_PROPERTY] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [LOAD_ATTR_GETATTRIBUTE_OVERRIDDEN] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },