1 // SPDX-License-Identifier: GPL-2.0
2
3 //! Our own `compiler_builtins`.
4 //!
5 //! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`].
6 //! Since we do not need the vast majority of them, we avoid the dependency
7 //! by providing this file.
8 //!
9 //! At the moment, some builtins are required that should not be. For instance,
10 //! [`core`] has 128-bit integers functionality which we should not be compiling
11 //! in. We will work with upstream [`core`] to provide feature flags to disable
12 //! the parts we do not need. For the moment, we define them to [`panic!`] at
13 //! runtime for simplicity to catch mistakes, instead of performing surgery
14 //! on `core.o`.
15 //!
16 //! In any case, all these symbols are weakened to ensure we do not override
17 //! those that may be provided by the rest of the kernel.
18 //!
19 //! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
20 //! [`compiler-rt`]: https://compiler-rt.llvm.org/
21
22 #![allow(internal_features)]
23 #![feature(compiler_builtins)]
24 #![compiler_builtins]
25 #![no_builtins]
26 #![no_std]
27
28 macro_rules! define_panicking_intrinsics(
29 ($reason: tt, { $($ident: ident, )* }) => {
30 $(
31 #[doc(hidden)]
32 #[export_name = concat!("__rust", stringify!($ident))]
33 pub extern "C" fn $ident() {
34 panic!($reason);
35 }
36 )*
37 }
38 );
39
40 define_panicking_intrinsics!("`f32` should not be used", {
41 __addsf3,
42 __eqsf2,
43 __gesf2,
44 __lesf2,
45 __ltsf2,
46 __mulsf3,
47 __nesf2,
48 __unordsf2,
49 });
50
51 define_panicking_intrinsics!("`f64` should not be used", {
52 __adddf3,
53 __ledf2,
54 __ltdf2,
55 __muldf3,
56 __unorddf2,
57 });
58
59 define_panicking_intrinsics!("`i128` should not be used", {
60 __ashrti3,
61 __muloti4,
62 __multi3,
63 });
64
65 define_panicking_intrinsics!("`u128` should not be used", {
66 __ashlti3,
67 __lshrti3,
68 __udivmodti4,
69 __udivti3,
70 __umodti3,
71 });
72
73 // NOTE: if you are adding a new intrinsic here, you should also add it to
74 // `redirect-intrinsics` in `rust/Makefile`.
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