Method invoke_exact_args

crates/vm/src/builtins/function.rs:728–758

Fast path for calling a simple function with exact positional args. Skips FuncArgs allocation, prepend_arg, and fill_locals_from_args. Only valid when: CO_OPTIMIZED, no VARARGS, no VARKEYWORDS, no kwonlyargs, and nargs == co_argcount.

(&self, args: Vec<PyObjectRef>, vm: &VirtualMachine)

    /// Only valid when: CO_OPTIMIZED, no VARARGS, no VARKEYWORDS, no kwonlyargs,
    /// and nargs == co_argcount.
    pub fn invoke_exact_args(&self, args: Vec<PyObjectRef>, vm: &VirtualMachine) -> PyResult {
        let code: PyRef<PyCode> = (*self.code).to_owned();

        debug_assert_eq!(args.len(), code.arg_count as usize);
        debug_assert!(code.flags.contains(bytecode::CodeFlags::OPTIMIZED));
        debug_assert!(
            !code
                .flags
                .intersects(bytecode::CodeFlags::VARARGS | bytecode::CodeFlags::VARKEYWORDS)
        );
        debug_assert_eq!(code.kwonlyarg_count, 0);

        // Generator/coroutine code objects are SIMPLE_FUNCTION in call
        // specialization classification, but their call path must still
        // go through invoke() to produce generator/coroutine objects.
        if code
            .flags
            .intersects(bytecode::CodeFlags::GENERATOR | bytecode::CodeFlags::COROUTINE)
        {
            return self.invoke(FuncArgs::from(args), vm);
        }
        let frame = self.prepare_exact_args_frame(args, vm);

        let result = vm.run_frame(frame.clone());
        unsafe {
            if let Some(base) = frame.materialize_localsplus() {
                vm.datastack_pop(base);
            }
        }
        result
    }
}

pub(crate) fn datastack_frame_size_bytes_for_code(code: &Py<PyCode>) -> Option<usize> {