1 files changed, 54 insertions, 0 deletions
diff --git a/compiler/rustc_hir/src/attrs/mod.rs b/compiler/rustc_hir/src/attrs/mod.rs
new file mode 100644
index 00000000000..482e6c90739
--- /dev/null
+++ b/compiler/rustc_hir/src/attrs/mod.rs
@@ -0,0 +1,54 @@
+//! Data structures for representing parsed attributes in the Rust compiler.
+//! Formerly `rustc_attr_data_structures`.
+//!
+//! For detailed documentation about attribute processing,
+//! see [rustc_attr_parsing](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_attr_parsing/index.html).
+
+pub use data_structures::*;
+pub use encode_cross_crate::EncodeCrossCrate;
+pub use pretty_printing::PrintAttribute;
+
+mod data_structures;
+mod encode_cross_crate;
+mod pretty_printing;
+
+/// Finds attributes in sequences of attributes by pattern matching.
+///
+/// A little like `matches` but for attributes.
+///
+/// ```rust,ignore (illustrative)
+/// // finds the repr attribute
+/// if let Some(r) = find_attr!(attrs, AttributeKind::Repr(r) => r) {
+///
+/// }
+///
+/// // checks if one has matched
+/// if find_attr!(attrs, AttributeKind::Repr(_)) {
+///
+/// }
+/// ```
+///
+/// Often this requires you to first end up with a list of attributes.
+/// A common way to get those is through `tcx.get_all_attrs(did)`
+#[macro_export]
+macro_rules! find_attr {
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)?) => {{
+        $crate::find_attr!($attributes_list, $pattern $(if $guard)? => ()).is_some()
+    }};
+
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)? => $e: expr) => {{
+        'done: {
+            for i in $attributes_list {
+                let i: &rustc_hir::Attribute = i;
+                match i {
+                    rustc_hir::Attribute::Parsed($pattern) $(if $guard)? => {
+                        break 'done Some($e);
+                    }
+                    _ => {}
+                }
+            }
+
+            None
+        }
+    }};
+}