gccrs: Resolve nested macro definition

We need to collect the early resolver's macros error to emit them at a
later stage after further expansion in order to retrieve macros defined
by other macro invocations.
Register some mappings for macro invocations and macro definitions.

gcc/rust/ChangeLog:

	* resolve/rust-early-name-resolver-2.0.cc (Early::visit):
	Collect error instead of emitting it. Also add invocation
	registration.
	* resolve/rust-early-name-resolver-2.0.h (std::function<void):
	Add type definition for collection.
	* resolve/rust-toplevel-name-resolver-2.0.cc (TopLevel::visit):
	Register macro rule definition in mappings.
	* rust-session-manager.cc (Session::expansion): Add macro
	resolve error collection.

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

4 files changed, 44 insertions, 3 deletions

diff --git a/gcc/rust/resolve/rust-early-name-resolver-2.0.cc b/gcc/rust/resolve/rust-early-name-resolver-2.0.cc
index df72d6e..a201bc4 100644
--- a/gcc/rust/resolve/rust-early-name-resolver-2.0.cc
+++ b/gcc/rust/resolve/rust-early-name-resolver-2.0.cc
@@ -135,13 +135,28 @@ Early::visit (AST::MacroInvocation &invoc)
   // if the definition still does not have a value, then it's an error
   if (!definition.has_value ())
     {
-      rust_error_at (invoc.get_locus (), ErrorCode::E0433,
-		     "could not resolve macro invocation");
+      collect_error ([&] () {
+	rust_error_at (invoc.get_locus (), ErrorCode::E0433,
+		       "could not resolve macro invocation");
+      });
       return;
     }
 
   // now do we need to keep mappings or something? or insert "uses" into our
   // ForeverStack? can we do that? are mappings simpler?
+  auto mappings = Analysis::Mappings::get ();
+  AST::MacroRulesDefinition *rules_def = nullptr;
+  if (!mappings->lookup_macro_def (definition.value (), &rules_def))
+    {
+      // Macro definition not found, maybe it is not expanded yet.
+      return;
+    }
+
+  AST::MacroRulesDefinition *tmp_def = nullptr;
+  if (mappings->lookup_macro_invocation (invoc, &tmp_def))
+    return;
+
+  mappings->insert_macro_invocation (invoc, rules_def);
 }
 
 void
diff --git a/gcc/rust/resolve/rust-early-name-resolver-2.0.h b/gcc/rust/resolve/rust-early-name-resolver-2.0.h
index fe83cf4..67785d0 100644
--- a/gcc/rust/resolve/rust-early-name-resolver-2.0.h
+++ b/gcc/rust/resolve/rust-early-name-resolver-2.0.h
@@ -28,6 +28,8 @@
 namespace Rust {
 namespace Resolver2_0 {
 
+using ResolveError = std::function<void ()>;
+
 class Early : public DefaultResolver
 {
   using DefaultResolver::visit;
@@ -37,6 +39,11 @@ public:
 
   void go (AST::Crate &crate);
 
+  const std::vector<ResolveError> &get_macro_resolve_errors () const
+  {
+    return macro_resolve_errors;
+  }
+
   // we need to handle definitions for textual scoping
   void visit (AST::MacroRulesDefinition &) override;
 
@@ -76,6 +83,9 @@ private:
   };
 
   TextualScope textual_scope;
+  std::vector<ResolveError> macro_resolve_errors;
+
+  void collect_error (ResolveError e) { macro_resolve_errors.push_back (e); }
 };
 
 } // namespace Resolver2_0
diff --git a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
index c28d922..e6c48d5 100644
--- a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
+++ b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
@@ -107,6 +107,13 @@ TopLevel::visit (AST::MacroRulesDefinition &macro)
 
   if (macro.get_kind () == AST::MacroRulesDefinition::MacroKind::DeclMacro)
     insert_or_error_out (macro.get_rule_name (), macro, Namespace::Macros);
+
+  auto mappings = Analysis::Mappings::get ();
+  AST::MacroRulesDefinition *tmp = nullptr;
+  if (mappings->lookup_macro_def (macro.get_node_id (), &tmp))
+    return;
+
+  mappings->insert_macro_def (&macro);
 }
 
 void
diff --git a/gcc/rust/rust-session-manager.cc b/gcc/rust/rust-session-manager.cc
index 1c5d729..8911e7d 100644
--- a/gcc/rust/rust-session-manager.cc
+++ b/gcc/rust/rust-session-manager.cc
@@ -874,6 +874,7 @@ Session::expansion (AST::Crate &crate)
   /* expand by calling cxtctxt object's monotonic_expander's expand_crate
    * method. */
   MacroExpander expander (crate, cfg, *this);
+  std::vector<Resolver2_0::ResolveError> macro_errors;
 
   while (!fixed_point_reached && iterations < cfg.recursion_limit)
     {
@@ -882,7 +883,11 @@ Session::expansion (AST::Crate &crate)
       auto ctx = Resolver2_0::NameResolutionContext ();
 
       if (flag_name_resolution_2_0)
-	Resolver2_0::Early (ctx).go (crate);
+	{
+	  Resolver2_0::Early early (ctx);
+	  early.go (crate);
+	  macro_errors = early.get_macro_resolve_errors ();
+	}
       else
 	Resolver::EarlyNameResolver ().go (crate);
 
@@ -896,6 +901,10 @@ Session::expansion (AST::Crate &crate)
 	break;
     }
 
+  // Fixed point reached: Emit unresolved macros error
+  for (auto &error : macro_errors)
+    error ();
+
   if (iterations == cfg.recursion_limit)
     {
       auto &last_invoc = expander.get_last_invocation ();