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Auto merge of #104219 - bryangarza:async-track-caller-dup, r=eholk

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Support `#[track_caller]` on async fns

Adds `#[track_caller]` to the generator that is created when we desugar the async fn.

Fixes #78840

Open questions:
- What is the performance impact of adding `#[track_caller]` to every `GenFuture`'s `poll(...)` function, even if it's unused (i.e., the parent span does not set `#[track_caller]`)? We might need to set it only conditionally, if the indirection causes overhead we don't want.
This commit is contained in:
bors 2022-11-17 13:47:03 +00:00
commit b6097f2e1b
4 changed files with 110 additions and 8 deletions
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39
compiler/rustc_ast_lowering/src/expr.rs
View file

@ -655,15 +655,40 @@ impl<'hir> LoweringContext<'_, 'hir> {
hir::ExprKind::Closure(c)
};
let generator = hir::Expr {
hir_id: self.lower_node_id(closure_node_id),
kind: generator_kind,
span: self.lower_span(span),
};
// `future::from_generator`:
let parent_has_track_caller = self
.attrs
.values()
.find(|attrs| attrs.into_iter().find(|attr| attr.has_name(sym::track_caller)).is_some())
.is_some();
let unstable_span =
self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
let hir_id = if parent_has_track_caller {
let generator_hir_id = self.lower_node_id(closure_node_id);
self.lower_attrs(
generator_hir_id,
&[Attribute {
kind: AttrKind::Normal(ptr::P(NormalAttr {
item: AttrItem {
path: Path::from_ident(Ident::new(sym::track_caller, span)),
args: MacArgs::Empty,
tokens: None,
},
tokens: None,
})),
id: self.tcx.sess.parse_sess.attr_id_generator.mk_attr_id(),
style: AttrStyle::Outer,
span: unstable_span,
}],
);
generator_hir_id
} else {
self.lower_node_id(closure_node_id)
};
let generator = hir::Expr { hir_id, kind: generator_kind, span: self.lower_span(span) };
// `future::from_generator`:
let gen_future = self.expr_lang_item_path(
unstable_span,
hir::LangItem::FromGenerator,