bjoernager/rust
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Remove Session.used_attrs and move logic to CheckAttrVisitor

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Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).

`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`

Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.

We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.

With this commit, a large source of global untracked state is removed.
This commit is contained in:
Aaron Hill 2021-07-29 12:00:41 -05:00
parent b6e334d873
commit af46699f81
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GPG key ID: B4087E510E98B164
62 changed files with 535 additions and 739 deletions
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38
compiler/rustc_session/src/session.rs
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@ -213,8 +213,6 @@ pub struct Session {
/// Set of enabled features for the current target.
pub target_features: FxHashSet<Symbol>,
used_attrs: Lock<MarkedAttrs>,
/// `Span`s for `if` conditions that we have suggested turning into `if let`.
pub if_let_suggestions: Lock<FxHashSet<Span>>,
}
@ -1066,39 +1064,14 @@ impl Session {
== config::InstrumentCoverage::ExceptUnusedFunctions
}
pub fn mark_attr_used(&self, attr: &Attribute) {
self.used_attrs.lock().mark(attr)
}
pub fn is_attr_used(&self, attr: &Attribute) -> bool {
self.used_attrs.lock().is_marked(attr)
}
/// Returns `true` if the attribute's path matches the argument. If it
/// matches, then the attribute is marked as used.
///
/// This method should only be used by rustc, other tools can use
/// `Attribute::has_name` instead, because only rustc is supposed to report
/// the `unused_attributes` lint. (`MetaItem` and `NestedMetaItem` are
/// produced by lowering an `Attribute` and don't have identity, so they
/// only have the `has_name` method, and you need to mark the original
/// `Attribute` as used when necessary.)
pub fn check_name(&self, attr: &Attribute, name: Symbol) -> bool {
let matches = attr.has_name(name);
if matches {
self.mark_attr_used(attr);
}
matches
}
pub fn is_proc_macro_attr(&self, attr: &Attribute) -> bool {
[sym::proc_macro, sym::proc_macro_attribute, sym::proc_macro_derive]
.iter()
.any(|kind| self.check_name(attr, *kind))
.any(|kind| attr.has_name(*kind))
}
pub fn contains_name(&self, attrs: &[Attribute], name: Symbol) -> bool {
attrs.iter().any(|item| self.check_name(item, name))
attrs.iter().any(|item| item.has_name(name))
}
pub fn find_by_name<'a>(
@ -1106,7 +1079,7 @@ impl Session {
attrs: &'a [Attribute],
name: Symbol,
) -> Option<&'a Attribute> {
attrs.iter().find(|attr| self.check_name(attr, name))
attrs.iter().find(|attr| attr.has_name(name))
}
pub fn filter_by_name<'a>(
@ -1114,7 +1087,7 @@ impl Session {
attrs: &'a [Attribute],
name: Symbol,
) -> impl Iterator<Item = &'a Attribute> {
attrs.iter().filter(move |attr| self.check_name(attr, name))
attrs.iter().filter(move |attr| attr.has_name(name))
}
pub fn first_attr_value_str_by_name(
@ -1122,7 +1095,7 @@ impl Session {
attrs: &[Attribute],
name: Symbol,
) -> Option<Symbol> {
attrs.iter().find(|at| self.check_name(at, name)).and_then(|at| at.value_str())
attrs.iter().find(|at| at.has_name(name)).and_then(|at| at.value_str())
}
}
@ -1359,7 +1332,6 @@ pub fn build_session(
miri_unleashed_features: Lock::new(Default::default()),
asm_arch,
target_features: FxHashSet::default(),
used_attrs: Lock::new(MarkedAttrs::new()),
if_let_suggestions: Default::default(),
};