[mypyc] Simplify argument parsing in legacy wrapper functions (#10234)

Only include the argument parsing functionality we need.

This speeds up the call_type_from_interpreted microbenchmark by about
17% on Python 3.8. This will also speed up most wrapper functions on Python 3.6
and earlier, since they don't use the new-style "fastcall" wrappers.

This also speeds up the test suite a little, since there's less code to compile.

Author: JukkaL

mypyc/codegen/emitwrapper.py

@@ -88,7 +88,7 @@ def make_static_kwlist(args: List[RuntimeArg]) -> str:
     return 'static const char * const kwlist[] = {{{}0}};'.format(arg_names)
 
 
-def make_format_string(func_name: str, groups: List[List[RuntimeArg]]) -> str:
+def make_format_string(func_name: Optional[str], groups: List[List[RuntimeArg]]) -> str:
     """Return a format string that specifies the accepted arguments.
 
     The format string is an extended subset of what is supported by
@@ -103,17 +103,19 @@ def make_format_string(func_name: str, groups: List[List[RuntimeArg]]) -> str:
 
     These are used by both vectorcall and legacy wrapper functions.
     """
-    main_format = ''
+    format = ''
     if groups[ARG_STAR] or groups[ARG_STAR2]:
-        main_format += '%'
-    main_format += 'O' * len(groups[ARG_POS])
+        format += '%'
+    format += 'O' * len(groups[ARG_POS])
     if groups[ARG_OPT] or groups[ARG_NAMED_OPT] or groups[ARG_NAMED]:
-        main_format += '|' + 'O' * len(groups[ARG_OPT])
+        format += '|' + 'O' * len(groups[ARG_OPT])
     if groups[ARG_NAMED_OPT] or groups[ARG_NAMED]:
-        main_format += '$' + 'O' * len(groups[ARG_NAMED_OPT])
+        format += '$' + 'O' * len(groups[ARG_NAMED_OPT])
     if groups[ARG_NAMED]:
-        main_format += '@' + 'O' * len(groups[ARG_NAMED])
-    return '{}:{}'.format(main_format, func_name)
+        format += '@' + 'O' * len(groups[ARG_NAMED])
+    if func_name is not None:
+        format += ':{}'.format(func_name)
+    return format
 
 
 def generate_wrapper_function(fn: FuncIR,
@@ -237,8 +239,8 @@ def generate_legacy_wrapper_function(fn: FuncIR,
     arg_ptrs += ['&obj_{}'.format(arg.name) for arg in reordered_args]
 
     emitter.emit_lines(
-        'if (!CPyArg_ParseTupleAndKeywords(args, kw, "{}", kwlist{})) {{'.format(
-            make_format_string(fn.name, groups), ''.join(', ' + n for n in arg_ptrs)),
+        'if (!CPyArg_ParseTupleAndKeywords(args, kw, "{}", "{}", kwlist{})) {{'.format(
+            make_format_string(None, groups), fn.name, ''.join(', ' + n for n in arg_ptrs)),
         'return NULL;',
         '}')
     traceback_code = generate_traceback_code(fn, emitter, source_path, module_name)

mypyc/lib-rt/CPy.h

@@ -516,7 +516,7 @@ CPyTagged CPyTagged_Id(PyObject *o);
 void CPyDebug_Print(const char *msg);
 void CPy_Init(void);
 int CPyArg_ParseTupleAndKeywords(PyObject *, PyObject *,
-                                 const char *, const char * const *, ...);
+                                 const char *, const char *, const char * const *, ...);
 int CPyArg_ParseStackAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
                                  CPyArg_Parser *parser, ...);
 int CPyArg_ParseStackAndKeywordsNoArgs(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
@@ -535,7 +535,6 @@ int CPyStatics_Initialize(PyObject **statics,
                           const double *complex_numbers,
                           const int *tuples);
 
-
 #ifdef __cplusplus
 }
 #endif