lowering: Add lowering of exported macros

Macros marked with #[macro_export] need to be lowered to HIR in order
to get exported to the relevant metadata files.

gcc/rust/ChangeLog:

	* hir/rust-ast-lower-base.cc (ASTLoweringBase::lower_macro_definition):
	New function.
	* hir/rust-ast-lower-base.h: Declare `lower_macro_definition`.
	* hir/rust-ast-lower-item.cc (ASTLoweringItem::visit): Lower public
	macro definitions.
	* hir/rust-ast-lower-stmt.cc (ASTLoweringStmt::visit): Likewise.
	* hir/rust-ast-lower-stmt.h: Add visitor for `AST::MacroRulesDefinition`.
	* hir/rust-ast-lower.cc (ASTLowering::go): Formatting.
	(ASTLoweringBlock::visit): Visit `AST::MacroRulesDefinition`
	(ASTLoweringIfLetBlock::visit): Formatting.
	(ASTLoweringExprWithBlock::visit): Formatting.

1 files changed, 16 insertions, 0 deletions

diff --git a/gcc/rust/hir/rust-ast-lower-base.cc b/gcc/rust/hir/rust-ast-lower-base.cc
index c21f511..972d34c 100644
--- a/gcc/rust/hir/rust-ast-lower-base.cc
+++ b/gcc/rust/hir/rust-ast-lower-base.cc
@@ -970,5 +970,21 @@ ASTLoweringBase::lower_extern_block (AST::ExternBlock &extern_block)
   return hir_extern_block;
 }
 
+void
+ASTLoweringBase::lower_macro_definition (AST::MacroRulesDefinition &def)
+{
+  auto is_export = false;
+  for (const auto &attr : def.get_outer_attrs ())
+    if (attr.get_path ().as_string () == "macro_export")
+      is_export = true;
+
+  if (is_export)
+    {
+      mappings->insert_exported_macro (def);
+      mappings->insert_ast_item (&def);
+      mappings->insert_location (def.get_node_id (), def.get_locus ());
+    }
+}
+
 } // namespace HIR
 } // namespace Rust