Support extern-blocks defined within blocks

This adds support for declaring extern blocks within blocks. So this adds
the missing name resolution visitor for the statement context. Then we
extract out a common extern block hir lowering function for both contexts.

The type resolution step needs to be updated to be like the code-generation
step so that we can solve these paths in a query rather than a top down
approach but this is a known issue.

The final step was to support query based compilation to extern functions.

Fixes #976

2 files changed, 40 insertions, 0 deletions

diff --git a/gcc/rust/resolve/rust-ast-resolve-stmt.cc b/gcc/rust/resolve/rust-ast-resolve-stmt.cc
new file mode 100644
index 0000000..6fc929f
--- /dev/null
+++ b/gcc/rust/resolve/rust-ast-resolve-stmt.cc
@@ -0,0 +1,38 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-ast-resolve-item.h"
+#include "rust-ast-resolve-stmt.h"
+
+namespace Rust {
+namespace Resolver {
+
+void
+ResolveStmt::visit (AST::ExternBlock &extern_block)
+{
+  resolve_visibility (extern_block.get_visibility ());
+  for (auto &item : extern_block.get_extern_items ())
+    {
+      ResolveToplevelExternItem::go (item.get (),
+				     CanonicalPath::create_empty ());
+      ResolveExternItem::go (item.get ());
+    }
+}
+
+} // namespace Resolver
+} // namespace Rust
diff --git a/gcc/rust/resolve/rust-ast-resolve-stmt.h b/gcc/rust/resolve/rust-ast-resolve-stmt.h
index 3afed53..c8d42bc 100644
--- a/gcc/rust/resolve/rust-ast-resolve-stmt.h
+++ b/gcc/rust/resolve/rust-ast-resolve-stmt.h
@@ -406,6 +406,8 @@ public:
     resolver->get_label_scope ().pop ();
   }
 
+  void visit (AST::ExternBlock &extern_block) override;
+
 private:
   ResolveStmt (NodeId parent, const CanonicalPath &prefix,
 	       const CanonicalPath &canonical_prefix,