1 files changed, 29 insertions, 1 deletions

diff --git a/Python/specialize.c b/Python/specialize.c
index 7b63393..13e0440 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -586,6 +586,7 @@ _PyCode_Quicken(PyCodeObject *code)
 static int function_kind(PyCodeObject *code);
 static bool function_check_args(PyObject *o, int expected_argcount, int opcode);
 static uint32_t function_get_version(PyObject *o, int opcode);
+static uint32_t type_get_version(PyTypeObject *t, int opcode);
 
 static int
 specialize_module_load_attr(
@@ -874,6 +875,9 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
     PyObject *descr = NULL;
     DescriptorClassification kind = analyze_descriptor(type, name, &descr, 0);
     assert(descr != NULL || kind == ABSENT || kind == GETSET_OVERRIDDEN);
+    if (type_get_version(type, LOAD_ATTR) == 0) {
+        goto fail;
+    }
     switch(kind) {
         case OVERRIDING:
             SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_OVERRIDING_DESCRIPTOR);
@@ -1057,6 +1061,9 @@ _Py_Specialize_StoreAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
     }
     PyObject *descr;
     DescriptorClassification kind = analyze_descriptor(type, name, &descr, 1);
+    if (type_get_version(type, STORE_ATTR) == 0) {
+        goto fail;
+    }
     switch(kind) {
         case OVERRIDING:
             SPECIALIZATION_FAIL(STORE_ATTR, SPEC_FAIL_ATTR_OVERRIDING_DESCRIPTOR);
@@ -1183,6 +1190,9 @@ specialize_class_load_attr(PyObject *owner, _Py_CODEUNIT *instr,
     PyObject *descr = NULL;
     DescriptorClassification kind = 0;
     kind = analyze_descriptor((PyTypeObject *)owner, name, &descr, 0);
+    if (type_get_version((PyTypeObject *)owner, LOAD_ATTR) == 0) {
+        return -1;
+    }
     switch (kind) {
         case METHOD:
         case NON_DESCRIPTOR:
@@ -1455,6 +1465,18 @@ function_get_version(PyObject *o, int opcode)
     return version;
 }
 
+/* Returning 0 indicates a failure. */
+static uint32_t
+type_get_version(PyTypeObject *t, int opcode)
+{
+    uint32_t version = t->tp_version_tag;
+    if (version == 0) {
+        SPECIALIZATION_FAIL(opcode, SPEC_FAIL_OUT_OF_VERSIONS);
+        return 0;
+    }
+    return version;
+}
+
 void
 _Py_Specialize_BinarySubscr(
      PyObject *container, PyObject *sub, _Py_CODEUNIT *instr)
@@ -1726,6 +1748,9 @@ specialize_class_call(PyObject *callable, _Py_CODEUNIT *instr, int nargs)
     }
     if (tp->tp_new == PyBaseObject_Type.tp_new) {
         PyFunctionObject *init = get_init_for_simple_managed_python_class(tp);
+        if (type_get_version(tp, CALL) == 0) {
+            return -1;
+        }
         if (init != NULL) {
             if (((PyCodeObject *)init->func_code)->co_argcount != nargs+1) {
                 SPECIALIZATION_FAIL(CALL, SPEC_FAIL_WRONG_NUMBER_ARGUMENTS);
@@ -2466,7 +2491,10 @@ _Py_Specialize_ToBool(PyObject *value, _Py_CODEUNIT *instr)
             SPECIALIZATION_FAIL(TO_BOOL, SPEC_FAIL_OUT_OF_VERSIONS);
             goto failure;
         }
-        uint32_t version = Py_TYPE(value)->tp_version_tag;
+        uint32_t version = type_get_version(Py_TYPE(value), TO_BOOL);
+        if (version == 0) {
+            goto failure;
+        }
         instr->op.code = TO_BOOL_ALWAYS_TRUE;
         write_u32(cache->version, version);
         assert(version);