gccrs: Use optional for proc macro invocation lookup

The old interface for those mappings was clunky at best. Now we can use
the optional structure to return a reference to the instance.

gcc/rust/ChangeLog:

	* expand/rust-macro-expand.h (struct MacroExpander): Update
	lookup function prototypes.
	* util/rust-hir-map.cc (Mappings::lookup_derive_proc_macro_invocation):
	Update lookup function according to new signature.
	(Mappings::lookup_bang_proc_macro_invocation): Likewise.
	(Mappings::lookup_attribute_proc_macro_invocation): Likewise.
	* util/rust-hir-map.h: Update function prototypes.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

3 files changed, 33 insertions, 35 deletions

diff --git a/gcc/rust/expand/rust-macro-expand.h b/gcc/rust/expand/rust-macro-expand.h
index 92103a7..f18e8e2 100644
--- a/gcc/rust/expand/rust-macro-expand.h
+++ b/gcc/rust/expand/rust-macro-expand.h
@@ -410,8 +410,9 @@ struct MacroExpander
   template <typename T>
   AST::Fragment expand_derive_proc_macro (T &item, AST::SimplePath &path)
   {
-    CustomDeriveProcMacro macro;
-    if (!mappings->lookup_derive_proc_macro_invocation (path, macro))
+    tl::optional<CustomDeriveProcMacro &> macro
+      = mappings->lookup_derive_proc_macro_invocation (path);
+    if (!macro.has_value ())
       {
 	rust_error_at (path.get_locus (), "Macro not found");
 	return AST::Fragment::create_error ();
@@ -424,15 +425,17 @@ struct MacroExpander
     auto c = collector.collect_tokens ();
     std::vector<const_TokenPtr> vec (c.cbegin (), c.cend ());
 
-    return parse_proc_macro_output (macro.get_handle () (convert (vec)));
+    return parse_proc_macro_output (
+      macro.value ().get_handle () (convert (vec)));
   }
 
   template <typename T>
   AST::Fragment expand_bang_proc_macro (T &item,
 					AST::MacroInvocation &invocation)
   {
-    BangProcMacro macro;
-    if (!mappings->lookup_bang_proc_macro_invocation (invocation, macro))
+    tl::optional<BangProcMacro &> macro
+      = mappings->lookup_bang_proc_macro_invocation (invocation);
+    if (!macro.has_value ())
       {
 	rust_error_at (invocation.get_locus (), "Macro not found");
 	return AST::Fragment::create_error ();
@@ -445,14 +448,16 @@ struct MacroExpander
     auto c = collector.collect_tokens ();
     std::vector<const_TokenPtr> vec (c.cbegin (), c.cend ());
 
-    return parse_proc_macro_output (macro.get_handle () (convert (vec)));
+    return parse_proc_macro_output (
+      macro.value ().get_handle () (convert (vec)));
   }
 
   template <typename T>
   AST::Fragment expand_attribute_proc_macro (T &item, AST::SimplePath &path)
   {
-    AttributeProcMacro macro;
-    if (!mappings->lookup_attribute_proc_macro_invocation (path, macro))
+    tl::optional<AttributeProcMacro &> macro
+      = mappings->lookup_attribute_proc_macro_invocation (path);
+    if (!macro.has_value ())
       {
 	rust_error_at (path.get_locus (), "Macro not found");
 	return AST::Fragment::create_error ();
@@ -467,8 +472,8 @@ struct MacroExpander
 
     // FIXME: Handle attributes
     return parse_proc_macro_output (
-      macro.get_handle () (ProcMacro::TokenStream::make_tokenstream (),
-			   convert (vec)));
+      macro.value ().get_handle () (ProcMacro::TokenStream::make_tokenstream (),
+				    convert (vec)));
   }
 
   /**
diff --git a/gcc/rust/util/rust-hir-map.cc b/gcc/rust/util/rust-hir-map.cc
index 7041aaa..6acec3d 100644
--- a/gcc/rust/util/rust-hir-map.cc
+++ b/gcc/rust/util/rust-hir-map.cc
@@ -1072,16 +1072,14 @@ Mappings::insert_derive_proc_macro_invocation (AST::SimplePath &invoc,
   procmacroDeriveInvocations[invoc.get_node_id ()] = def;
 }
 
-bool
-Mappings::lookup_derive_proc_macro_invocation (AST::SimplePath &invoc,
-					       CustomDeriveProcMacro &def)
+tl::optional<CustomDeriveProcMacro &>
+Mappings::lookup_derive_proc_macro_invocation (AST::SimplePath &invoc)
 {
   auto it = procmacroDeriveInvocations.find (invoc.get_node_id ());
   if (it == procmacroDeriveInvocations.end ())
-    return false;
+    return tl::nullopt;
 
-  def = it->second;
-  return true;
+  return it->second;
 }
 
 void
@@ -1094,16 +1092,14 @@ Mappings::insert_bang_proc_macro_invocation (AST::MacroInvocation &invoc,
   procmacroBangInvocations[invoc.get_macro_node_id ()] = def;
 }
 
-bool
-Mappings::lookup_bang_proc_macro_invocation (AST::MacroInvocation &invoc,
-					     BangProcMacro &def)
+tl::optional<BangProcMacro &>
+Mappings::lookup_bang_proc_macro_invocation (AST::MacroInvocation &invoc)
 {
   auto it = procmacroBangInvocations.find (invoc.get_macro_node_id ());
   if (it == procmacroBangInvocations.end ())
-    return false;
+    return tl::nullopt;
 
-  def = it->second;
-  return true;
+  return it->second;
 }
 
 void
@@ -1116,16 +1112,14 @@ Mappings::insert_attribute_proc_macro_invocation (AST::SimplePath &invoc,
   procmacroAttributeInvocations[invoc.get_node_id ()] = def;
 }
 
-bool
-Mappings::lookup_attribute_proc_macro_invocation (AST::SimplePath &invoc,
-						  AttributeProcMacro &def)
+tl::optional<AttributeProcMacro &>
+Mappings::lookup_attribute_proc_macro_invocation (AST::SimplePath &invoc)
 {
   auto it = procmacroAttributeInvocations.find (invoc.get_node_id ());
   if (it == procmacroAttributeInvocations.end ())
-    return false;
+    return tl::nullopt;
 
-  def = it->second;
-  return true;
+  return it->second;
 }
 
 void
diff --git a/gcc/rust/util/rust-hir-map.h b/gcc/rust/util/rust-hir-map.h
index 06d117d..177bcba 100644
--- a/gcc/rust/util/rust-hir-map.h
+++ b/gcc/rust/util/rust-hir-map.h
@@ -310,19 +310,18 @@ public:
   bool lookup_bang_proc_macro_def (NodeId id, BangProcMacro &macro);
   bool lookup_attribute_proc_macro_def (NodeId id, AttributeProcMacro &macro);
 
+  tl::optional<CustomDeriveProcMacro &>
+  lookup_derive_proc_macro_invocation (AST::SimplePath &invoc);
+  tl::optional<BangProcMacro &>
+  lookup_bang_proc_macro_invocation (AST::MacroInvocation &invoc_id);
+  tl::optional<AttributeProcMacro &>
+  lookup_attribute_proc_macro_invocation (AST::SimplePath &invoc);
   void insert_derive_proc_macro_invocation (AST::SimplePath &invoc,
 					    CustomDeriveProcMacro def);
-
-  bool lookup_derive_proc_macro_invocation (AST::SimplePath &invoc,
-					    CustomDeriveProcMacro &def);
   void insert_bang_proc_macro_invocation (AST::MacroInvocation &invoc,
 					  BangProcMacro def);
-  bool lookup_bang_proc_macro_invocation (AST::MacroInvocation &invoc_id,
-					  BangProcMacro &def);
   void insert_attribute_proc_macro_invocation (AST::SimplePath &invoc,
 					       AttributeProcMacro def);
-  bool lookup_attribute_proc_macro_invocation (AST::SimplePath &invoc,
-					       AttributeProcMacro &def);
 
   void insert_visibility (NodeId id, Privacy::ModuleVisibility visibility);
   bool lookup_visibility (NodeId id, Privacy::ModuleVisibility &def);