1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
//! Used by `rustc` when compiling a plugin crate.
use rustc_hir as hir;
use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
use rustc_hir::itemlikevisit::ItemLikeVisitor;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_span::symbol::sym;
use rustc_span::Span;
struct RegistrarFinder<'tcx> {
tcx: TyCtxt<'tcx>,
registrars: Vec<(hir::HirId, Span)>,
}
impl<'v, 'tcx> ItemLikeVisitor<'v> for RegistrarFinder<'tcx> {
fn visit_item(&mut self, item: &hir::Item<'_>) {
if let hir::ItemKind::Fn(..) = item.kind {
if self.tcx.sess.contains_name(&item.attrs, sym::plugin_registrar) {
self.registrars.push((item.hir_id, item.span));
}
}
}
fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) {}
fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) {}
fn visit_foreign_item(&mut self, _foreign_item: &hir::ForeignItem<'_>) {}
}
/// Finds the function marked with `#[plugin_registrar]`, if any.
pub fn find_plugin_registrar(tcx: TyCtxt<'_>) -> Option<DefId> {
tcx.plugin_registrar_fn(LOCAL_CRATE)
}
fn plugin_registrar_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
assert_eq!(cnum, LOCAL_CRATE);
let mut finder = RegistrarFinder { tcx, registrars: Vec::new() };
tcx.hir().krate().visit_all_item_likes(&mut finder);
match finder.registrars.len() {
0 => None,
1 => {
let (hir_id, _) = finder.registrars.pop().unwrap();
Some(tcx.hir().local_def_id(hir_id).to_def_id())
}
_ => {
let diagnostic = tcx.sess.diagnostic();
let mut e = diagnostic.struct_err("multiple plugin registration functions found");
for &(_, span) in &finder.registrars {
e.span_note(span, "one is here");
}
e.emit();
diagnostic.abort_if_errors();
unreachable!();
}
}
}
pub fn provide(providers: &mut Providers) {
*providers = Providers { plugin_registrar_fn, ..*providers };
}
|
