Implement dict clear C helper function

Author: vsakkas

mypyc/lib-rt/CPy.h

@@ -347,6 +347,7 @@ PyObject *CPyDict_ItemsView(PyObject *dict);
 PyObject *CPyDict_Keys(PyObject *dict);
 PyObject *CPyDict_Values(PyObject *dict);
 PyObject *CPyDict_Items(PyObject *dict);
+void CPyDict_Clear(PyObject *dict);
 PyObject *CPyDict_GetKeysIter(PyObject *dict);
 PyObject *CPyDict_GetItemsIter(PyObject *dict);
 PyObject *CPyDict_GetValuesIter(PyObject *dict);

mypyc/lib-rt/dict_ops.c

@@ -226,6 +226,14 @@ PyObject *CPyDict_Items(PyObject *dict) {
     return list;
 }
 
+void CPyDict_Clear(PyObject *dict) {
+    if (PyDict_CheckExact(dict)) {
+        PyDict_Clear(dict);
+    } else {
+        PyObject_CallMethod(dict, "clear", NULL);
+    }
+}
+
 PyObject *CPyDict_GetKeysIter(PyObject *dict) {
     if (PyDict_CheckExact(dict)) {
         // Return dict itself to indicate we can use fast path instead.

mypyc/primitives/dict_ops.py

@@ -143,11 +143,11 @@
     error_kind=ERR_MAGIC)
 
 # dict.clear()
-c_method_op(
+method_op(
     name='clear',
     arg_types=[dict_rprimitive],
     return_type=void_rtype,
-    c_function_name='PyDict_Clear',
+    c_function_name='CPyDict_Clear',
     error_kind=ERR_NEVER)
 
 # list(dict.keys())

mypyc/test-data/irbuild-dict.test

@@ -321,5 +321,5 @@ def f(d: Dict[int, int]) -> None:
 def f(d):
     d :: dict
 L0:
-    PyDict_Clear(d)
+    CPyDict_Clear(d)
     return 1