gccrs: Clean BiMap to use tl::optional for lookups

gcc/rust/Changelog:

	* expand/rust-expand-visitor.cc
	(ExpandVisitor::expand_inner_items): Adjust to use has_value ()
	(ExpandVisitor::expand_inner_stmts): Likewise
	* expand/rust-macro-builtins.cc (builtin_macro_from_string): Likewise
	(make_macro_path_str): Likewise
	* util/rust-hir-map.cc (Mappings::insert_macro_def): Likewise
	* util/rust-lang-item.cc (LangItem::Parse): Adjust to return tl::optional
	(LangItem::toString) Likewise
	* util/rust-token-converter.cc (handle_suffix): Adjust to use value.or ()
	(from_literal) Likewise
	* util/bi-map.h (BiMap::lookup): Adjust to use tl::optional for
	lookups

Signed-off-by: Sourabh Jaiswal <sourabhrj31@gmail.com>

4 files changed, 20 insertions, 15 deletions

diff --git a/gcc/rust/util/bi-map.h b/gcc/rust/util/bi-map.h
index ff26c83..bc4f580 100644
--- a/gcc/rust/util/bi-map.h
+++ b/gcc/rust/util/bi-map.h
@@ -24,9 +24,6 @@
 // very simple bi-directional hashmap
 template <typename K, typename V> class BiMap
 {
-  using v_iter = typename std::unordered_map<K, V>::const_iterator;
-  using k_iter = typename std::unordered_map<V, K>::const_iterator;
-
 public:
   BiMap (std::unordered_map<K, V> &&original) : map (std::move (original))
   {
@@ -34,11 +31,22 @@ public:
       rmap.insert ({kv.second, kv.first});
   }
 
-  const v_iter lookup (const K &key) const { return map.find (key); }
-  const k_iter lookup (const V &key) const { return rmap.find (key); }
+  const tl::optional<const V &> lookup (const K &key) const
+  {
+    auto itr = map.find (key);
+    if (itr == map.end ())
+      return tl::nullopt;
+
+    return itr->second;
+  }
+  const tl::optional<const K &> lookup (const V &key) const
+  {
+    auto itr = rmap.find (key);
+    if (itr == rmap.end ())
+      return tl::nullopt;
 
-  bool is_iter_ok (const v_iter &iter) const { return iter != map.end (); }
-  bool is_iter_ok (const k_iter &iter) const { return iter != rmap.end (); }
+    return itr->second;
+  }
 
 private:
   std::unordered_map<K, V> map;
diff --git a/gcc/rust/util/rust-hir-map.cc b/gcc/rust/util/rust-hir-map.cc
index 1f7cb4d..c62c111 100644
--- a/gcc/rust/util/rust-hir-map.cc
+++ b/gcc/rust/util/rust-hir-map.cc
@@ -880,7 +880,7 @@ Mappings::insert_macro_def (AST::MacroRulesDefinition *macro)
     {
       auto builtin
 	= MacroBuiltin::builtins.lookup (macro->get_rule_name ().as_string ());
-      if (!MacroBuiltin::builtins.is_iter_ok (builtin))
+      if (!builtin.has_value ())
 	{
 	  rust_error_at (macro->get_locus (),
 			 "cannot find a built-in macro with name %qs",
diff --git a/gcc/rust/util/rust-lang-item.cc b/gcc/rust/util/rust-lang-item.cc
index 38df90f..0d8a98077 100644
--- a/gcc/rust/util/rust-lang-item.cc
+++ b/gcc/rust/util/rust-lang-item.cc
@@ -97,17 +97,15 @@ tl::optional<LangItem::Kind>
 LangItem::Parse (const std::string &item)
 {
   auto lang_item = LangItem::lang_items.lookup (item);
-  if (!LangItem::lang_items.is_iter_ok (lang_item))
-    return tl::nullopt;
 
-  return lang_item->second;
+  return lang_item;
 }
 
 std::string
 LangItem::ToString (LangItem::Kind type)
 {
   auto str = LangItem::lang_items.lookup (type);
-  return str->second;
+  return str.value ();
 }
 
 LangItem::Kind
diff --git a/gcc/rust/util/rust-token-converter.cc b/gcc/rust/util/rust-token-converter.cc
index 41f8105..220e891 100644
--- a/gcc/rust/util/rust-token-converter.cc
+++ b/gcc/rust/util/rust-token-converter.cc
@@ -67,7 +67,7 @@ handle_suffix (const const_TokenPtr &token, ProcMacro::LitKind kind)
 {
   auto str = token->as_string ();
   auto lookup = suffixes.lookup (token->get_type_hint ());
-  auto suffix = suffixes.is_iter_ok (lookup) ? lookup->second : "";
+  auto suffix = lookup.value_or ("");
   return ProcMacro::Literal::make_literal (kind, convert (token->get_locus ()),
 					   str, suffix);
 }
@@ -296,8 +296,7 @@ from_literal (const ProcMacro::Literal &literal,
 {
   auto lookup = suffixes.lookup (literal.suffix.to_string ());
   auto loc = convert (literal.span);
-  auto suffix
-    = suffixes.is_iter_ok (lookup) ? lookup->second : CORETYPE_UNKNOWN;
+  auto suffix = lookup.value_or (CORETYPE_UNKNOWN);
   // FIXME: Add spans instead of empty locations
   switch (literal.kind.tag)
     {