1 //! LLVM-frontend specific AVR calling convention implementation.
3 //! # Current calling convention ABI
5 //! Inherited from Clang's `clang::DefaultABIInfo` implementation - self described
8 //! > the default implementation for ABI specific details. This implementation
9 //! > provides information which results in
10 //! > self-consistent and sensible LLVM IR generation, but does not
11 //! > conform to any particular ABI.
13 //! > - Doxygen Doxumentation of `clang::DefaultABIInfo`
15 //! This calling convention may not match AVR-GCC in all cases.
17 //! In the future, an AVR-GCC compatible argument classification ABI should be
18 //! adopted in both Rust and Clang.
20 //! *NOTE*: Currently, this module implements the same calling convention
21 //! that clang with AVR currently does - the default, simple, unspecialized
22 //! ABI implementation available to all targets. This ABI is not
23 //! binary-compatible with AVR-GCC. Once LLVM [PR46140](https://bugs.llvm.org/show_bug.cgi?id=46140)
24 //! is completed, this module should be updated to match so that both Clang
25 //! and Rust emit code to the same AVR-GCC compatible ABI.
27 //! In particular, both Clang and Rust may not have the same semantics
28 //! when promoting arguments to indirect references as AVR-GCC. It is important
29 //! to note that the core AVR ABI implementation within LLVM itself is ABI
30 //! compatible with AVR-GCC - Rust and AVR-GCC only differ in the small amount
31 //! of compiler frontend specific calling convention logic implemented here.
33 use crate::abi::call::{ArgAbi, FnAbi};
35 fn classify_ret_ty<Ty>(ret: &mut ArgAbi<'_, Ty>) {
36 if ret.layout.is_aggregate() {
41 fn classify_arg_ty<Ty>(arg: &mut ArgAbi<'_, Ty>) {
42 if arg.layout.is_aggregate() {
47 pub fn compute_abi_info<Ty>(fty: &mut FnAbi<'_, Ty>) {
48 if !fty.ret.is_ignore() {
49 classify_ret_ty(&mut fty.ret);
52 for arg in fty.args.iter_mut() {