rustc_middle/middle/
exported_symbols.rs

Help
1use rustc_hir::def_id::{DefId, LOCAL_CRATE};
2use rustc_macros::{Decodable, Encodable, HashStable, TyDecodable, TyEncodable};
3
4use crate::ty::{self, GenericArgsRef, Ty, TyCtxt};
5
6/// The SymbolExportLevel of a symbols specifies from which kinds of crates
7/// the symbol will be exported. `C` symbols will be exported from any
8/// kind of crate, including cdylibs which export very few things.
9/// `Rust` will only be exported if the crate produced is a Rust
10/// dylib.
11#[derive(Eq, PartialEq, Debug, Copy, Clone, TyEncodable, TyDecodable, HashStable)]
12pub enum SymbolExportLevel {
13    C,
14    Rust,
15}
16
17impl SymbolExportLevel {
18    pub fn is_below_threshold(self, threshold: SymbolExportLevel) -> bool {
19        threshold == SymbolExportLevel::Rust // export everything from Rust dylibs
20          || self == SymbolExportLevel::C
21    }
22}
23
24/// Kind of exported symbols.
25#[derive(Eq, PartialEq, Debug, Copy, Clone, Encodable, Decodable, HashStable)]
26pub enum SymbolExportKind {
27    Text,
28    Data,
29    Tls,
30}
31
32/// The `SymbolExportInfo` of a symbols specifies symbol-related information
33/// that is relevant to code generation and linking.
34#[derive(Eq, PartialEq, Debug, Copy, Clone, TyEncodable, TyDecodable, HashStable)]
35pub struct SymbolExportInfo {
36    pub level: SymbolExportLevel,
37    pub kind: SymbolExportKind,
38    pub used: bool,
39}
40
41#[derive(Eq, PartialEq, Debug, Copy, Clone, TyEncodable, TyDecodable, HashStable)]
42pub enum ExportedSymbol<'tcx> {
43    NonGeneric(DefId),
44    Generic(DefId, GenericArgsRef<'tcx>),
45    DropGlue(Ty<'tcx>),
46    AsyncDropGlueCtorShim(Ty<'tcx>),
47    ThreadLocalShim(DefId),
48    NoDefId(ty::SymbolName<'tcx>),
49}
50
51impl<'tcx> ExportedSymbol<'tcx> {
52    /// This is the symbol name of an instance if it is instantiated in the
53    /// local crate.
54    pub fn symbol_name_for_local_instance(&self, tcx: TyCtxt<'tcx>) -> ty::SymbolName<'tcx> {
55        match *self {
56            ExportedSymbol::NonGeneric(def_id) => tcx.symbol_name(ty::Instance::mono(tcx, def_id)),
57            ExportedSymbol::Generic(def_id, args) => {
58                tcx.symbol_name(ty::Instance::new(def_id, args))
59            }
60            ExportedSymbol::DropGlue(ty) => {
61                tcx.symbol_name(ty::Instance::resolve_drop_in_place(tcx, ty))
62            }
63            ExportedSymbol::AsyncDropGlueCtorShim(ty) => {
64                tcx.symbol_name(ty::Instance::resolve_async_drop_in_place(tcx, ty))
65            }
66            ExportedSymbol::ThreadLocalShim(def_id) => tcx.symbol_name(ty::Instance {
67                def: ty::InstanceKind::ThreadLocalShim(def_id),
68                args: ty::GenericArgs::empty(),
69            }),
70            ExportedSymbol::NoDefId(symbol_name) => symbol_name,
71        }
72    }
73}
74
75pub fn metadata_symbol_name(tcx: TyCtxt<'_>) -> String {
76    format!(
77        "rust_metadata_{}_{:08x}",
78        tcx.crate_name(LOCAL_CRATE),
79        tcx.stable_crate_id(LOCAL_CRATE),
80    )
81}
rustc_middle/middle/exported_symbols.rs

rustc_middle/middle/
exported_symbols.rs
