gccrs: Check for deprecated attributes

Deprecated attributes need to be checked and proper errors
should be produced on bad arguments.

gcc/rust/ChangeLog:

	* util/rust-attributes.cc: New function to handle deprecated attribute checking

Signed-off-by: Ashwani Kumar Kamal <ashwanikamal.im421@gmail.com>

diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index 70f26e7ce361ba20b1e93253b137762da840bc63..ea6d1cd178d7945a19526a0cfb95094f6118d5a8 100644 (file)
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -277,6 +277,97 @@ check_doc_attribute (const AST::Attribute &attribute)
     }
 }
 
+static void
+check_deprecated_attribute (const AST::Attribute &attribute)
+{
+  const auto &input = attribute.get_attr_input ();
+
+  if (input.get_attr_input_type () != AST::AttrInput::META_ITEM)
+    return;
+
+  auto &meta = static_cast<const AST::AttrInputMetaItemContainer &> (input);
+
+  for (auto &current : meta.get_items ())
+    {
+      switch (current->get_kind ())
+       {
+       case AST::MetaItemInner::Kind::MetaItem:
+         {
+           auto *meta_item = static_cast<AST::MetaItem *> (current.get ());
+
+           switch (meta_item->get_item_kind ())
+             {
+             case AST::MetaItem::ItemKind::NameValueStr:
+               {
+                 auto *nv = static_cast<AST::MetaNameValueStr *> (meta_item);
+
+                 const std::string key = nv->get_name ().as_string ();
+
+                 if (key != "since" && key != "note")
+                   {
+                     rust_error_at (nv->get_locus (), "unknown meta item %qs",
+                                    key.c_str ());
+                     rust_inform (nv->get_locus (),
+                                  "expected one of %<since%>, %<note%>");
+                   }
+               }
+               break;
+
+             case AST::MetaItem::ItemKind::Path:
+               {
+                 // #[deprecated(a,a)]
+                 auto *p = static_cast<AST::MetaItemPath *> (meta_item);
+
+                 std::string ident = p->get_path ().as_string ();
+
+                 rust_error_at (p->get_locus (), "unknown meta item %qs",
+                                ident.c_str ());
+                 rust_inform (p->get_locus (),
+                              "expected one of %<since%>, %<note%>");
+               }
+               break;
+
+             case AST::MetaItem::ItemKind::Word:
+               {
+                 // #[deprecated("a")]
+                 auto *w = static_cast<AST::MetaWord *> (meta_item);
+
+                 rust_error_at (
+                   w->get_locus (),
+                   "item in %<deprecated%> must be a key/value pair");
+               }
+               break;
+
+             case AST::MetaItem::ItemKind::PathExpr:
+               {
+                 // #[deprecated(since=a)]
+                 auto *px = static_cast<AST::MetaItemPathExpr *> (meta_item);
+
+                 rust_error_at (
+                   px->get_locus (),
+                   "expected unsuffixed literal or identifier, found %qs",
+                   px->get_expr ().as_string ().c_str ());
+               }
+               break;
+
+             case AST::MetaItem::ItemKind::Seq:
+             case AST::MetaItem::ItemKind::ListPaths:
+             case AST::MetaItem::ItemKind::ListNameValueStr:
+             default:
+               gcc_unreachable ();
+               break;
+             }
+         }
+         break;
+
+       case AST::MetaItemInner::Kind::LitExpr:
+       default:
+         gcc_unreachable ();
+         break;
+       }
+    }
+}
+
 static bool
 is_proc_macro_type (const AST::Attribute &attribute)
 {
@@ -370,6 +461,8 @@ AttributeChecker::check_attribute (const AST::Attribute &attribute)
   // and costly
   if (result.name == Attrs::DOC)
     check_doc_attribute (attribute);
+  else if (result.name == Attrs::DEPRECATED)
+    check_deprecated_attribute (attribute);
 }
 
 void