Port #[register_tool] to the new attribute parsers

Co-authored-by: Jana Dönszelmann <jana@donsz.nl>

compiler/rustc_attr_parsing/src/attributes/crate_level.rs

@@ -347,3 +347,50 @@ impl<S: Stage> CombineAttributeParser<S> for FeatureParser {
         res
     }
 }
+
+pub(crate) struct RegisterToolParser;
+
+impl<S: Stage> CombineAttributeParser<S> for RegisterToolParser {
+    const PATH: &[Symbol] = &[sym::register_tool];
+    type Item = Ident;
+    const CONVERT: ConvertFn<Self::Item> = AttributeKind::RegisterTool;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS);
+    const TEMPLATE: AttributeTemplate = template!(List: &["tool1, tool2, ..."]);
+
+    fn extend(
+        cx: &mut AcceptContext<'_, '_, S>,
+        args: &ArgParser,
+    ) -> impl IntoIterator<Item = Self::Item> {
+        let ArgParser::List(list) = args else {
+            cx.expected_list(cx.attr_span, args);
+            return Vec::new();
+        };
+
+        if list.is_empty() {
+            cx.warn_empty_attribute(cx.attr_span);
+        }
+
+        let mut res = Vec::new();
+
+        for elem in list.mixed() {
+            let Some(elem) = elem.meta_item() else {
+                cx.expected_identifier(elem.span());
+                continue;
+            };
+            if let Err(arg_span) = elem.args().no_args() {
+                cx.expected_no_args(arg_span);
+                continue;
+            }
+
+            let path = elem.path();
+            let Some(ident) = path.word() else {
+                cx.expected_identifier(path.span());
+                continue;
+            };
+
+            res.push(ident);
+        }
+
+        res
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -160,6 +160,7 @@ attribute_parsers!(
         Combine<FeatureParser>,
         Combine<ForceTargetFeatureParser>,
         Combine<LinkParser>,
+        Combine<RegisterToolParser>,
         Combine<ReprParser>,
         Combine<RustcCleanParser>,
         Combine<RustcLayoutParser>,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -1139,6 +1139,9 @@ pub enum AttributeKind {
     /// Represents `#[reexport_test_harness_main]`
     ReexportTestHarnessMain(Symbol),
 
+    /// Represents `#[register_tool]`
+    RegisterTool(ThinVec<Ident>, Span),
+
     /// Represents [`#[repr]`](https://doc.rust-lang.org/stable/reference/type-layout.html#representations).
     Repr {
         reprs: ThinVec<(ReprAttr, Span)>,

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -92,6 +92,7 @@ impl AttributeKind {
             ProfilerRuntime => No,
             RecursionLimit { .. } => No,
             ReexportTestHarnessMain(..) => No,
+            RegisterTool(..) => No,
             Repr { .. } => No,
             RustcAbi { .. } => No,
             RustcAllocator => No,

compiler/rustc_passes/src/check_attr.rs

@@ -289,6 +289,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::ProfilerRuntime
                     | AttributeKind::RecursionLimit { .. }
                     | AttributeKind::ReexportTestHarnessMain(..)
+                    | AttributeKind::RegisterTool(..)
                     // handled below this loop and elsewhere
                     | AttributeKind::Repr { .. }
                     | AttributeKind::RustcAbi { .. }
@@ -407,8 +408,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::rustc_layout
                             | sym::rustc_autodiff
                             // crate-level attrs, are checked below
-                            | sym::feature
-                            | sym::register_tool,
+                            | sym::feature,
                             ..
                         ] => {}
                         [name, rest@..] => {