rustdoc: Clean & fix up attribute rendering

src/librustdoc/clean/types.rs

@@ -801,50 +801,6 @@ impl Item {
         Some(tcx.visibility(def_id))
     }
 
-    /// Get a list of attributes excluding `#[repr]` to display.
-    ///
-    /// Only used by the HTML output-format.
-    fn attributes_without_repr(&self) -> Vec<String> {
-        self.attrs
-            .other_attrs
-            .iter()
-            .filter_map(|attr| match attr {
-                hir::Attribute::Parsed(AttributeKind::LinkSection { name, .. }) => {
-                    Some(format!("#[unsafe(link_section = \"{name}\")]"))
-                }
-                hir::Attribute::Parsed(AttributeKind::NoMangle(..)) => {
-                    Some("#[unsafe(no_mangle)]".to_string())
-                }
-                hir::Attribute::Parsed(AttributeKind::ExportName { name, .. }) => {
-                    Some(format!("#[unsafe(export_name = \"{name}\")]"))
-                }
-                hir::Attribute::Parsed(AttributeKind::NonExhaustive(..)) => {
-                    Some("#[non_exhaustive]".to_string())
-                }
-                _ => None,
-            })
-            .collect()
-    }
-
-    /// Get a list of attributes to display on this item.
-    ///
-    /// Only used by the HTML output-format.
-    pub(crate) fn attributes(&self, tcx: TyCtxt<'_>, cache: &Cache) -> Vec<String> {
-        let mut attrs = self.attributes_without_repr();
-
-        if let Some(repr_attr) = self.repr(tcx, cache) {
-            attrs.push(repr_attr);
-        }
-        attrs
-    }
-
-    /// Returns a stringified `#[repr(...)]` attribute.
-    ///
-    /// Only used by the HTML output-format.
-    pub(crate) fn repr(&self, tcx: TyCtxt<'_>, cache: &Cache) -> Option<String> {
-        repr_attributes(tcx, cache, self.def_id()?, self.type_())
-    }
-
     pub fn is_doc_hidden(&self) -> bool {
         self.attrs.is_doc_hidden()
     }
@@ -854,74 +810,6 @@ impl Item {
     }
 }
 
-/// Return a string representing the `#[repr]` attribute if present.
-///
-/// Only used by the HTML output-format.
-pub(crate) fn repr_attributes(
-    tcx: TyCtxt<'_>,
-    cache: &Cache,
-    def_id: DefId,
-    item_type: ItemType,
-) -> Option<String> {
-    use rustc_abi::IntegerType;
-
-    if !matches!(item_type, ItemType::Struct | ItemType::Enum | ItemType::Union) {
-        return None;
-    }
-    let adt = tcx.adt_def(def_id);
-    let repr = adt.repr();
-    let mut out = Vec::new();
-    if repr.c() {
-        out.push("C");
-    }
-    if repr.transparent() {
-        // Render `repr(transparent)` iff the non-1-ZST field is public or at least one
-        // field is public in case all fields are 1-ZST fields.
-        let render_transparent = cache.document_private
-            || adt
-                .all_fields()
-                .find(|field| {
-                    let ty = field.ty(tcx, ty::GenericArgs::identity_for_item(tcx, field.did));
-                    tcx.layout_of(ty::TypingEnv::post_analysis(tcx, field.did).as_query_input(ty))
-                        .is_ok_and(|layout| !layout.is_1zst())
-                })
-                .map_or_else(
-                    || adt.all_fields().any(|field| field.vis.is_public()),
-                    |field| field.vis.is_public(),
-                );
-
-        if render_transparent {
-            out.push("transparent");
-        }
-    }
-    if repr.simd() {
-        out.push("simd");
-    }
-    let pack_s;
-    if let Some(pack) = repr.pack {
-        pack_s = format!("packed({})", pack.bytes());
-        out.push(&pack_s);
-    }
-    let align_s;
-    if let Some(align) = repr.align {
-        align_s = format!("align({})", align.bytes());
-        out.push(&align_s);
-    }
-    let int_s;
-    if let Some(int) = repr.int {
-        int_s = match int {
-            IntegerType::Pointer(is_signed) => {
-                format!("{}size", if is_signed { 'i' } else { 'u' })
-            }
-            IntegerType::Fixed(size, is_signed) => {
-                format!("{}{}", if is_signed { 'i' } else { 'u' }, size.size().bytes() * 8)
-            }
-        };
-        out.push(&int_s);
-    }
-    if !out.is_empty() { Some(format!("#[repr({})]", out.join(", "))) } else { None }
-}
-
 #[derive(Clone, Debug)]
 pub(crate) enum ItemKind {
     ExternCrateItem {

src/librustdoc/html/render/mod.rs

@@ -51,7 +51,9 @@ use askama::Template;
 use itertools::Either;
 use rustc_ast::join_path_syms;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
-use rustc_hir::attrs::{DeprecatedSince, Deprecation};
+use rustc_hir as hir;
+use rustc_hir::attrs::{AttributeKind, DeprecatedSince, Deprecation};
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_hir::{ConstStability, Mutability, RustcVersion, StabilityLevel, StableSince};
 use rustc_middle::ty::print::PrintTraitRefExt;
@@ -1310,43 +1312,6 @@ fn render_assoc_item(
     })
 }
 
-struct CodeAttribute(String);
-
-fn render_code_attribute(prefix: &str, code_attr: CodeAttribute, w: &mut impl fmt::Write) {
-    write!(
-        w,
-        "<div class=\"code-attribute\">{prefix}{attr}</div>",
-        prefix = prefix,
-        attr = code_attr.0
-    )
-    .unwrap();
-}
-
-// When an attribute is rendered inside a <code> tag, it is formatted using
-// a div to produce a newline after it.
-fn render_attributes_in_code(
-    w: &mut impl fmt::Write,
-    it: &clean::Item,
-    prefix: &str,
-    cx: &Context<'_>,
-) {
-    for attr in it.attributes(cx.tcx(), cx.cache()) {
-        render_code_attribute(prefix, CodeAttribute(attr), w);
-    }
-}
-
-/// used for type aliases to only render their `repr` attribute.
-fn render_repr_attributes_in_code(
-    w: &mut impl fmt::Write,
-    cx: &Context<'_>,
-    def_id: DefId,
-    item_type: ItemType,
-) {
-    if let Some(repr) = clean::repr_attributes(cx.tcx(), cx.cache(), def_id, item_type) {
-        render_code_attribute("", CodeAttribute(repr), w);
-    }
-}
-
 #[derive(Copy, Clone)]
 enum AssocItemLink<'a> {
     Anchor(Option<&'a str>),
@@ -2959,3 +2924,102 @@ fn render_call_locations<W: fmt::Write>(
 
     w.write_str("</div>")
 }
+
+fn render_attributes_in_code(
+    w: &mut impl fmt::Write,
+    item: &clean::Item,
+    prefix: &str,
+    cx: &Context<'_>,
+) {
+    for attr in &item.attrs.other_attrs {
+        let hir::Attribute::Parsed(kind) = attr else { continue };
+        let attr = match kind {
+            AttributeKind::LinkSection { name, .. } => {
+                Cow::Owned(format!("#[unsafe(link_section = {})]", Escape(&format!("{name:?}"))))
+            }
+            AttributeKind::NoMangle(..) => Cow::Borrowed("#[unsafe(no_mangle)]"),
+            AttributeKind::ExportName { name, .. } => {
+                Cow::Owned(format!("#[unsafe(export_name = {})]", Escape(&format!("{name:?}"))))
+            }
+            AttributeKind::NonExhaustive(..) => Cow::Borrowed("#[non_exhaustive]"),
+            _ => continue,
+        };
+        render_code_attribute(prefix, attr.as_ref(), w);
+    }
+
+    if let Some(def_id) = item.def_id()
+        && let Some(repr) = repr_attribute(cx.tcx(), cx.cache(), def_id)
+    {
+        render_code_attribute(prefix, &repr, w);
+    }
+}
+
+fn render_repr_attribute_in_code(w: &mut impl fmt::Write, cx: &Context<'_>, def_id: DefId) {
+    if let Some(repr) = repr_attribute(cx.tcx(), cx.cache(), def_id) {
+        render_code_attribute("", &repr, w);
+    }
+}
+
+fn render_code_attribute(prefix: &str, attr: &str, w: &mut impl fmt::Write) {
+    write!(w, "<div class=\"code-attribute\">{prefix}{attr}</div>").unwrap();
+}
+
+fn repr_attribute<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    cache: &Cache,
+    def_id: DefId,
+) -> Option<Cow<'static, str>> {
+    let adt = match tcx.def_kind(def_id) {
+        DefKind::Struct | DefKind::Enum | DefKind::Union => tcx.adt_def(def_id),
+        _ => return None,
+    };
+    let repr = adt.repr();
+
+    if repr.transparent() {
+        // Render `repr(transparent)` iff the non-1-ZST field is public or at least one
+        // field is public in case all fields are 1-ZST fields.
+        let render_transparent = cache.document_private
+            || adt
+                .all_fields()
+                .find(|field| {
+                    let ty = field.ty(tcx, ty::GenericArgs::identity_for_item(tcx, field.did));
+                    tcx.layout_of(ty::TypingEnv::post_analysis(tcx, field.did).as_query_input(ty))
+                        .is_ok_and(|layout| !layout.is_1zst())
+                })
+                .map_or_else(
+                    || adt.all_fields().any(|field| field.vis.is_public()),
+                    |field| field.vis.is_public(),
+                );
+
+        // Since the transparent repr can't have any other reprs or
+        // repr modifiers beside it, we can safely return early here.
+        return render_transparent.then(|| "#[repr(transparent)]".into());
+    }
+
+    let mut result = Vec::<Cow<'_, _>>::new();
+
+    if repr.c() {
+        result.push("C".into());
+    }
+    if repr.simd() {
+        result.push("simd".into());
+    }
+    if let Some(pack) = repr.pack {
+        result.push(format!("packed({})", pack.bytes()).into());
+    }
+    if let Some(align) = repr.align {
+        result.push(format!("align({})", align.bytes()).into());
+    }
+    if let Some(int) = repr.int {
+        let prefix = if int.is_signed() { 'i' } else { 'u' };
+        let int = match int {
+            rustc_abi::IntegerType::Pointer(_) => format!("{prefix}size"),
+            rustc_abi::IntegerType::Fixed(int, _) => {
+                format!("{prefix}{}", int.size().bytes() * 8)
+            }
+        };
+        result.push(int.into());
+    }
+
+    (!result.is_empty()).then(|| format!("#[repr({})]", result.join(", ")).into())
+}

src/librustdoc/html/render/print_item.rs

@@ -21,7 +21,7 @@ use super::{
     collect_paths_for_type, document, ensure_trailing_slash, get_filtered_impls_for_reference,
     item_ty_to_section, notable_traits_button, notable_traits_json, render_all_impls,
     render_assoc_item, render_assoc_items, render_attributes_in_code, render_impl,
-    render_repr_attributes_in_code, render_rightside, render_stability_since_raw,
+    render_repr_attribute_in_code, render_rightside, render_stability_since_raw,
     render_stability_since_raw_with_extra, write_section_heading,
 };
 use crate::clean;
@@ -1555,7 +1555,7 @@ impl<'clean> DisplayEnum<'clean> {
         wrap_item(w, |w| {
             if is_type_alias {
                 // For now the only attributes we render for type aliases are `repr` attributes.
-                render_repr_attributes_in_code(w, cx, self.def_id, ItemType::Enum);
+                render_repr_attribute_in_code(w, cx, self.def_id);
             } else {
                 render_attributes_in_code(w, it, "", cx);
             }
@@ -2017,7 +2017,7 @@ impl<'a> DisplayStruct<'a> {
         wrap_item(w, |w| {
             if is_type_alias {
                 // For now the only attributes we render for type aliases are `repr` attributes.
-                render_repr_attributes_in_code(w, cx, self.def_id, ItemType::Struct);
+                render_repr_attribute_in_code(w, cx, self.def_id);
             } else {
                 render_attributes_in_code(w, it, "", cx);
             }
@@ -2371,7 +2371,7 @@ fn render_union(
     fmt::from_fn(move |mut f| {
         if is_type_alias {
             // For now the only attributes we render for type aliases are `repr` attributes.
-            render_repr_attributes_in_code(f, cx, def_id, ItemType::Union);
+            render_repr_attribute_in_code(f, cx, def_id);
         } else {
             render_attributes_in_code(f, it, "", cx);
         }

tests/rustdoc/attributes.rs

@@ -9,6 +9,18 @@ pub extern "C" fn f() {}
 #[unsafe(export_name = "bar")]
 pub extern "C" fn g() {}
 
+//@ has foo/fn.escape_special.html '//*[@class="code-attribute"]' \
+//                                 '#[unsafe(export_name = "\n\"\n")]'
+#[unsafe(export_name = "\n\"
+")]
+pub extern "C" fn escape_special() {}
+
+// issue: <https://github.com/rust-lang/rust/issues/142835>
+//@ has foo/fn.escape_html.html '//*[@class="code-attribute"]' \
+//                              '#[unsafe(export_name = "<script>alert()</script>")]'
+#[unsafe(export_name = "<script>alert()</script>")]
+pub extern "C" fn escape_html() {}
+
 //@ has foo/fn.example.html '//*[@class="code-attribute"]' '#[unsafe(link_section = ".text")]'
 #[unsafe(link_section = ".text")]
 pub extern "C" fn example() {}

tests/rustdoc/inline_cross/attributes.rs

@@ -1,7 +1,20 @@
+// Ensure that we render attributes on inlined cross-crate re-exported items.
+// issue: <https://github.com/rust-lang/rust/issues/144004>
+
 //@ aux-crate:attributes=attributes.rs
 //@ edition:2021
 #![crate_name = "user"]
 
-//@ has 'user/struct.NonExhaustive.html'
-//@ has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[non_exhaustive]'
+//@ has 'user/fn.no_mangle.html' '//pre[@class="rust item-decl"]' '#[unsafe(no_mangle)]'
+pub use attributes::no_mangle;
+
+//@ has 'user/fn.link_section.html' '//pre[@class="rust item-decl"]' \
+//                                  '#[unsafe(link_section = ".here")]'
+pub use attributes::link_section;
+
+//@ has 'user/fn.export_name.html' '//pre[@class="rust item-decl"]' \
+//                                 '#[unsafe(export_name = "exonym")]'
+pub use attributes::export_name;
+
+//@ has 'user/struct.NonExhaustive.html' '//pre[@class="rust item-decl"]' '#[non_exhaustive]'
 pub use attributes::NonExhaustive;

tests/rustdoc/inline_cross/auxiliary/attributes.rs

@@ -1,2 +1,11 @@
+#[unsafe(no_mangle)]
+pub fn no_mangle() {}
+
+#[unsafe(link_section = ".here")]
+pub fn link_section() {}
+
+#[unsafe(export_name = "exonym")]
+pub fn export_name() {}
+
 #[non_exhaustive]
 pub struct NonExhaustive;