Rust provides `compiler_builtins` as a port of LLVM's `compiler-rt`. Since we do not need the vast majority of them, we avoid the dependency by providing our own crate. Co-developed-by: Alex Gaynor <alex.gaynor@xxxxxxxxx> Signed-off-by: Alex Gaynor <alex.gaynor@xxxxxxxxx> Co-developed-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx> Signed-off-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx> Co-developed-by: Sven Van Asbroeck <thesven73@xxxxxxxxx> Signed-off-by: Sven Van Asbroeck <thesven73@xxxxxxxxx> Co-developed-by: Gary Guo <gary@xxxxxxxxxxx> Signed-off-by: Gary Guo <gary@xxxxxxxxxxx> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx> --- rust/compiler_builtins.rs | 57 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 rust/compiler_builtins.rs diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs new file mode 100644 index 000000000000..a5a0be72591b --- /dev/null +++ b/rust/compiler_builtins.rs @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Our own `compiler_builtins`. +//! +//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`]. +//! Since we do not need the vast majority of them, we avoid the dependency +//! by providing this file. +//! +//! At the moment, some builtins are required that should not be. For instance, +//! [`core`] has floating-point functionality which we should not be compiling +//! in. We will work with upstream [`core`] to provide feature flags to disable +//! the parts we do not need. For the moment, we define them to [`panic!`] at +//! runtime for simplicity to catch mistakes, instead of performing surgery +//! on `core.o`. +//! +//! In any case, all these symbols are weakened to ensure we do not override +//! those that may be provided by the rest of the kernel. +//! +//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins +//! [`compiler-rt`]: https://compiler-rt.llvm.org/ + +#![feature(compiler_builtins)] +#![compiler_builtins] +#![no_builtins] +#![no_std] + +macro_rules! define_panicking_intrinsics( + ($reason: tt, { $($ident: ident, )* }) => { + $( + #[doc(hidden)] + #[no_mangle] + pub extern "C" fn $ident() { + panic!($reason); + } + )* + } +); + +define_panicking_intrinsics!("`i128` should not be used", { + __ashrti3, + __muloti4, + __multi3, +}); + +define_panicking_intrinsics!("`u128` should not be used", { + __ashlti3, + __lshrti3, + __udivmodti4, + __udivti3, + __umodti3, +}); + +#[cfg(target_arch = "arm")] +define_panicking_intrinsics!("`u64` division/modulo should not be used", { + __aeabi_uldivmod, + __mulodi4, +}); -- 2.34.0
