rustc_ast_lowering/
stability.rs

1use std::fmt;
2
3use rustc_abi::ExternAbi;
4use rustc_feature::Features;
5use rustc_session::Session;
6use rustc_session::diagnostics::feature_err;
7use rustc_span::symbol::sym;
8use rustc_span::{Span, Symbol};
9
10pub(crate) fn enabled_names(features: &rustc_feature::Features, span: Span) -> Vec<&'static str> {
11    ExternAbi::ALL_VARIANTS
12        .into_iter()
13        .filter(|abi| extern_abi_enabled(features, span, **abi).is_ok())
14        .map(|abi| abi.as_str())
15        .collect()
16}
17
18pub(crate) fn extern_abi_enabled(
19    features: &rustc_feature::Features,
20    span: Span,
21    abi: ExternAbi,
22) -> Result<(), UnstableAbi> {
23    extern_abi_stability(abi).or_else(|unstable @ UnstableAbi { feature, .. }| {
24        if features.enabled(feature) || span.allows_unstable(feature) {
25            Ok(())
26        } else {
27            Err(unstable)
28        }
29    })
30}
31
32pub(crate) fn gate_unstable_abi(sess: &Session, features: &Features, span: Span, abi: ExternAbi) {
33    match extern_abi_enabled(features, span, abi) {
34        Ok(_) => (),
35        Err(unstable_abi) => {
36            let explain = unstable_abi.to_string();
37            feature_err(sess, unstable_abi.feature, span, explain).emit();
38        }
39    }
40}
41
42pub struct UnstableAbi {
43    abi: ExternAbi,
44    feature: Symbol,
45    explain: GateReason,
46}
47
48enum GateReason {
49    Experimental,
50    ImplDetail,
51}
52
53impl fmt::Display for UnstableAbi {
54    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
55        let Self { abi, .. } = self;
56        match self.explain {
57            GateReason::Experimental => {
58                f.write_fmt(format_args!("the extern {0} ABI is experimental and subject to change",
        abi))write!(f, "the extern {abi} ABI is experimental and subject to change")
59            }
60            GateReason::ImplDetail => {
61                f.write_fmt(format_args!("the extern {0} ABI is an implementation detail and perma-unstable",
        abi))write!(f, "the extern {abi} ABI is an implementation detail and perma-unstable")
62            }
63        }
64    }
65}
66
67pub fn extern_abi_stability(abi: ExternAbi) -> Result<(), UnstableAbi> {
68    match abi {
69        // stable ABIs
70        ExternAbi::Rust
71        | ExternAbi::C { .. }
72        | ExternAbi::Cdecl { .. }
73        | ExternAbi::Custom
74        | ExternAbi::Stdcall { .. }
75        | ExternAbi::Fastcall { .. }
76        | ExternAbi::Thiscall { .. }
77        | ExternAbi::Aapcs { .. }
78        | ExternAbi::Win64 { .. }
79        | ExternAbi::SysV64 { .. }
80        | ExternAbi::System { .. }
81        | ExternAbi::EfiApi => Ok(()),
82        ExternAbi::LlvmIntrinsic => Err(UnstableAbi {
83            abi,
84            feature: sym::link_llvm_intrinsics,
85            explain: GateReason::ImplDetail,
86        }),
87        // experimental
88        ExternAbi::Vectorcall { .. } => Err(UnstableAbi {
89            abi,
90            feature: sym::abi_vectorcall,
91            explain: GateReason::Experimental,
92        }),
93        ExternAbi::RustCall => Err(UnstableAbi {
94            abi,
95            feature: sym::unboxed_closures,
96            explain: GateReason::Experimental,
97        }),
98        ExternAbi::RustCold => {
99            Err(UnstableAbi { abi, feature: sym::rust_cold_cc, explain: GateReason::Experimental })
100        }
101        ExternAbi::RustPreserveNone => Err(UnstableAbi {
102            abi,
103            feature: sym::rust_preserve_none_cc,
104            explain: GateReason::Experimental,
105        }),
106        ExternAbi::RustTail => {
107            Err(UnstableAbi { abi, feature: sym::rust_tail_cc, explain: GateReason::Experimental })
108        }
109        ExternAbi::RustInvalid => {
110            Err(UnstableAbi { abi, feature: sym::rustc_attrs, explain: GateReason::ImplDetail })
111        }
112        ExternAbi::GpuKernel => Err(UnstableAbi {
113            abi,
114            feature: sym::abi_gpu_kernel,
115            explain: GateReason::Experimental,
116        }),
117        ExternAbi::PtxKernel => {
118            Err(UnstableAbi { abi, feature: sym::abi_ptx, explain: GateReason::Experimental })
119        }
120        ExternAbi::Msp430Interrupt => Err(UnstableAbi {
121            abi,
122            feature: sym::abi_msp430_interrupt,
123            explain: GateReason::Experimental,
124        }),
125        ExternAbi::X86Interrupt => Err(UnstableAbi {
126            abi,
127            feature: sym::abi_x86_interrupt,
128            explain: GateReason::Experimental,
129        }),
130        ExternAbi::AvrInterrupt | ExternAbi::AvrNonBlockingInterrupt => Err(UnstableAbi {
131            abi,
132            feature: sym::abi_avr_interrupt,
133            explain: GateReason::Experimental,
134        }),
135        ExternAbi::RiscvInterruptM | ExternAbi::RiscvInterruptS => Err(UnstableAbi {
136            abi,
137            feature: sym::abi_riscv_interrupt,
138            explain: GateReason::Experimental,
139        }),
140        ExternAbi::CmseNonSecureCall => Err(UnstableAbi {
141            abi,
142            feature: sym::abi_cmse_nonsecure_call,
143            explain: GateReason::Experimental,
144        }),
145        ExternAbi::CmseNonSecureEntry => Err(UnstableAbi {
146            abi,
147            feature: sym::cmse_nonsecure_entry,
148            explain: GateReason::Experimental,
149        }),
150        ExternAbi::Swift => {
151            Err(UnstableAbi { abi, feature: sym::abi_swift, explain: GateReason::Experimental })
152        }
153    }
154}
rustc_ast_lowering/stability.rs

rustc_ast_lowering/
stability.rs
