"""Generate CPython API wrapper function for a native function.""" from typing import List, Optional from mypy.nodes import ARG_POS, ARG_OPT, ARG_NAMED_OPT, ARG_NAMED, ARG_STAR, ARG_STAR2 from mypyc.common import PREFIX, NATIVE_PREFIX, DUNDER_PREFIX from mypyc.codegen.emit import Emitter from mypyc.ir.rtypes import ( RType, is_object_rprimitive, is_int_rprimitive, is_bool_rprimitive, object_rprimitive ) from mypyc.ir.func_ir import FuncIR, RuntimeArg, FUNC_STATICMETHOD from mypyc.ir.class_ir import ClassIR from mypyc.namegen import NameGenerator def wrapper_function_header(fn: FuncIR, names: NameGenerator) -> str: return 'PyObject *{prefix}{name}(PyObject *self, PyObject *args, PyObject *kw)'.format( prefix=PREFIX, name=fn.cname(names)) def make_format_string(func_name: str, groups: List[List[RuntimeArg]]) -> str: # Construct the format string. Each group requires the previous # groups delimiters to be present first. main_format = '' if groups[ARG_STAR] or groups[ARG_STAR2]: main_format += '%' main_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]) if groups[ARG_NAMED_OPT] or groups[ARG_NAMED]: main_format += '$' + 'O' * len(groups[ARG_NAMED_OPT]) if groups[ARG_NAMED]: main_format += '@' + 'O' * len(groups[ARG_NAMED]) return '{}:{}'.format(main_format, func_name) def generate_wrapper_function(fn: FuncIR, emitter: Emitter, source_path: str, module_name: str) -> None: """Generates a CPython-compatible wrapper function for a native function. In particular, this handles unboxing the arguments, calling the native function, and then boxing the return value. """ emitter.emit_line('{} {{'.format(wrapper_function_header(fn, emitter.names))) # If we hit an error while processing arguments, then we emit a # traceback frame to make it possible to debug where it happened. # Unlike traceback frames added for exceptions seen in IR, we do this # even if there is no `traceback_name`. This is because the error will # have originated here and so we need it in the traceback. globals_static = emitter.static_name('globals', module_name) traceback_code = 'CPy_AddTraceback("%s", "%s", %d, %s);' % ( source_path.replace("\\", "\\\\"), fn.traceback_name or fn.name, fn.line, globals_static) # If fn is a method, then the first argument is a self param real_args = list(fn.args) if fn.class_name and not fn.decl.kind == FUNC_STATICMETHOD: arg = real_args.pop(0) emitter.emit_line('PyObject *obj_{} = self;'.format(arg.name)) # Need to order args as: required, optional, kwonly optional, kwonly required # This is because CPyArg_ParseTupleAndKeywords format string requires # them grouped in that way. groups = [[arg for arg in real_args if arg.kind == k] for k in range(ARG_NAMED_OPT + 1)] reordered_args = groups[ARG_POS] + groups[ARG_OPT] + groups[ARG_NAMED_OPT] + groups[ARG_NAMED] arg_names = ''.join('"{}", '.format(arg.name) for arg in reordered_args) emitter.emit_line('static char *kwlist[] = {{{}0}};'.format(arg_names)) for arg in real_args: emitter.emit_line('PyObject *obj_{}{};'.format( arg.name, ' = NULL' if arg.optional else '')) cleanups = ['CPy_DECREF(obj_{});'.format(arg.name) for arg in groups[ARG_STAR] + groups[ARG_STAR2]] arg_ptrs = [] # type: List[str] if groups[ARG_STAR] or groups[ARG_STAR2]: arg_ptrs += ['&obj_{}'.format(groups[ARG_STAR][0].name) if groups[ARG_STAR] else 'NULL'] arg_ptrs += ['&obj_{}'.format(groups[ARG_STAR2][0].name) if groups[ARG_STAR2] else 'NULL'] 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)), 'return NULL;', '}') generate_wrapper_core(fn, emitter, groups[ARG_OPT] + groups[ARG_NAMED_OPT], cleanups=cleanups, traceback_code=traceback_code) emitter.emit_line('}') def generate_dunder_wrapper(cl: ClassIR, fn: FuncIR, emitter: Emitter) -> str: """Generates a wrapper for native __dunder__ methods to be able to fit into the mapping protocol slot. This specifically means that the arguments are taken as *PyObjects and returned as *PyObjects. """ input_args = ', '.join('PyObject *obj_{}'.format(arg.name) for arg in fn.args) name = '{}{}{}'.format(DUNDER_PREFIX, fn.name, cl.name_prefix(emitter.names)) emitter.emit_line('static PyObject *{name}({input_args}) {{'.format( name=name, input_args=input_args, )) generate_wrapper_core(fn, emitter) emitter.emit_line('}') return name RICHCOMPARE_OPS = { '__lt__': 'Py_LT', '__gt__': 'Py_GT', '__le__': 'Py_LE', '__ge__': 'Py_GE', '__eq__': 'Py_EQ', '__ne__': 'Py_NE', } def generate_richcompare_wrapper(cl: ClassIR, emitter: Emitter) -> Optional[str]: """Generates a wrapper for richcompare dunder methods.""" # Sort for determinism on Python 3.5 matches = sorted([name for name in RICHCOMPARE_OPS if cl.has_method(name)]) if not matches: return None name = '{}_RichCompare_{}'.format(DUNDER_PREFIX, cl.name_prefix(emitter.names)) emitter.emit_line( 'static PyObject *{name}(PyObject *obj_lhs, PyObject *obj_rhs, int op) {{'.format( name=name) ) emitter.emit_line('switch (op) {') for func in matches: emitter.emit_line('case {}: {{'.format(RICHCOMPARE_OPS[func])) method = cl.get_method(func) assert method is not None generate_wrapper_core(method, emitter, arg_names=['lhs', 'rhs']) emitter.emit_line('}') emitter.emit_line('}') emitter.emit_line('Py_INCREF(Py_NotImplemented);') emitter.emit_line('return Py_NotImplemented;') emitter.emit_line('}') return name def generate_get_wrapper(cl: ClassIR, fn: FuncIR, emitter: Emitter) -> str: """Generates a wrapper for native __get__ methods.""" name = '{}{}{}'.format(DUNDER_PREFIX, fn.name, cl.name_prefix(emitter.names)) emitter.emit_line( 'static PyObject *{name}(PyObject *self, PyObject *instance, PyObject *owner) {{'. format(name=name)) emitter.emit_line('instance = instance ? instance : Py_None;') emitter.emit_line('return {}{}(self, instance, owner);'.format( NATIVE_PREFIX, fn.cname(emitter.names))) emitter.emit_line('}') return name def generate_hash_wrapper(cl: ClassIR, fn: FuncIR, emitter: Emitter) -> str: """Generates a wrapper for native __hash__ methods.""" name = '{}{}{}'.format(DUNDER_PREFIX, fn.name, cl.name_prefix(emitter.names)) emitter.emit_line('static Py_ssize_t {name}(PyObject *self) {{'.format( name=name )) emitter.emit_line('{}retval = {}{}{}(self);'.format(emitter.ctype_spaced(fn.ret_type), emitter.get_group_prefix(fn.decl), NATIVE_PREFIX, fn.cname(emitter.names))) emitter.emit_error_check('retval', fn.ret_type, 'return -1;') if is_int_rprimitive(fn.ret_type): emitter.emit_line('Py_ssize_t val = CPyTagged_AsSsize_t(retval);') else: emitter.emit_line('Py_ssize_t val = PyLong_AsSsize_t(retval);') emitter.emit_dec_ref('retval', fn.ret_type) emitter.emit_line('if (PyErr_Occurred()) return -1;') # We can't return -1 from a hash function.. emitter.emit_line('if (val == -1) return -2;') emitter.emit_line('return val;') emitter.emit_line('}') return name def generate_bool_wrapper(cl: ClassIR, fn: FuncIR, emitter: Emitter) -> str: """Generates a wrapper for native __bool__ methods.""" name = '{}{}{}'.format(DUNDER_PREFIX, fn.name, cl.name_prefix(emitter.names)) emitter.emit_line('static int {name}(PyObject *self) {{'.format( name=name )) emitter.emit_line('{}val = {}{}(self);'.format(emitter.ctype_spaced(fn.ret_type), NATIVE_PREFIX, fn.cname(emitter.names))) emitter.emit_error_check('val', fn.ret_type, 'return -1;') # This wouldn't be that hard to fix but it seems unimportant and # getting error handling and unboxing right would be fiddly. (And # way easier to do in IR!) assert is_bool_rprimitive(fn.ret_type), "Only bool return supported for __bool__" emitter.emit_line('return val;') emitter.emit_line('}') return name def generate_wrapper_core(fn: FuncIR, emitter: Emitter, optional_args: Optional[List[RuntimeArg]] = None, arg_names: Optional[List[str]] = None, cleanups: Optional[List[str]] = None, traceback_code: Optional[str] = None) -> None: """Generates the core part of a wrapper function for a native function. This expects each argument as a PyObject * named obj_{arg} as a precondition. It converts the PyObject *s to the necessary types, checking and unboxing if necessary, makes the call, then boxes the result if necessary and returns it. """ optional_args = optional_args or [] cleanups = cleanups or [] use_goto = bool(cleanups or traceback_code) error_code = 'return NULL;' if not use_goto else 'goto fail;' arg_names = arg_names or [arg.name for arg in fn.args] for arg_name, arg in zip(arg_names, fn.args): # Suppress the argument check for *args/**kwargs, since we know it must be right. typ = arg.type if arg.kind not in (ARG_STAR, ARG_STAR2) else object_rprimitive generate_arg_check(arg_name, typ, emitter, error_code, arg in optional_args) native_args = ', '.join('arg_{}'.format(arg) for arg in arg_names) if fn.ret_type.is_unboxed or use_goto: # TODO: The Py_RETURN macros return the correct PyObject * with reference count handling. # Are they relevant? emitter.emit_line('{}retval = {}{}({});'.format(emitter.ctype_spaced(fn.ret_type), NATIVE_PREFIX, fn.cname(emitter.names), native_args)) emitter.emit_lines(*cleanups) if fn.ret_type.is_unboxed: emitter.emit_error_check('retval', fn.ret_type, 'return NULL;') emitter.emit_box('retval', 'retbox', fn.ret_type, declare_dest=True) emitter.emit_line('return {};'.format('retbox' if fn.ret_type.is_unboxed else 'retval')) else: emitter.emit_line('return {}{}({});'.format(NATIVE_PREFIX, fn.cname(emitter.names), native_args)) # TODO: Tracebacks? if use_goto: emitter.emit_label('fail') emitter.emit_lines(*cleanups) if traceback_code: emitter.emit_lines(traceback_code) emitter.emit_lines('return NULL;') def generate_arg_check(name: str, typ: RType, emitter: Emitter, error_code: str, optional: bool = False) -> None: """Insert a runtime check for argument and unbox if necessary. The object is named PyObject *obj_{}. This is expected to generate a value of name arg_{} (unboxed if necessary). For each primitive a runtime check ensures the correct type. """ if typ.is_unboxed: # Borrow when unboxing to avoid reference count manipulation. emitter.emit_unbox('obj_{}'.format(name), 'arg_{}'.format(name), typ, error_code, declare_dest=True, borrow=True, optional=optional) elif is_object_rprimitive(typ): # Object is trivial since any object is valid if optional: emitter.emit_line('PyObject *arg_{};'.format(name)) emitter.emit_line('if (obj_{} == NULL) {{'.format(name)) emitter.emit_line('arg_{} = {};'.format(name, emitter.c_error_value(typ))) emitter.emit_lines('} else {', 'arg_{} = obj_{}; '.format(name, name), '}') else: emitter.emit_line('PyObject *arg_{} = obj_{};'.format(name, name)) else: emitter.emit_cast('obj_{}'.format(name), 'arg_{}'.format(name), typ, declare_dest=True, optional=optional) if optional: emitter.emit_line('if (obj_{} != NULL && arg_{} == NULL) {}'.format( name, name, error_code)) else: emitter.emit_line('if (arg_{} == NULL) {}'.format(name, error_code))