expand: Add new ExpandVisitor class

This class takes care of actually performing the macro expansion by calling
into the MacroExpander for each node of a given AST, leaving the job of
cfg-stripping nodes to the AttrVisitor.

gcc/rust/ChangeLog:

	* Make-lang.in: Add new object file.
	* expand/rust-attribute-visitor.cc (AttrVisitor::go): Visit all items of a
	crate.
	(AttrVisitor::expand_struct_fields): Do not perform macro expansion anymore.
	(AttrVisitor::expand_function_params): Likewise.
	(AttrVisitor::expand_generic_args): Likewise.
	(AttrVisitor::expand_qualified_path_type): Likewise.
	(AttrVisitor::expand_self_param): Likewise.
	(AttrVisitor::expand_trait_function_decl): Likewise.
	(AttrVisitor::expand_trait_method_decl): Likewise.
	(AttrVisitor::visit): Likewise.
	(AttrVisitor::maybe_expand_expr): Remove function.
	(AttrVisitor::maybe_expand_type): Likewise.
	* expand/rust-attribute-visitor.h: Do not keep MacroExpander inside AttrVisitor
	anymore.
	* expand/rust-macro-expand.h (struct MacroExpander): Turn ContextType into an
	enum class for more type safety.
	* expand/rust-macro-expand.cc (MacroExpander::expand_crate): Use new ContextType
	API.
	* rust-session-manager.cc (Session::expansion): Call into ExpandVisitor.
	* expand/rust-expand-visitor.cc: New file.
	* expand/rust-expand-visitor.h: New file.

gcc/testsuite/ChangeLog:

	* rust/compile/macro49.rs: New test.
	* rust/compile/macro50.rs: New test.

1 files changed, 4 insertions, 3 deletions

diff --git a/gcc/rust/rust-session-manager.cc b/gcc/rust/rust-session-manager.cc
index ce1fdbb..66863f4 100644
--- a/gcc/rust/rust-session-manager.cc
+++ b/gcc/rust/rust-session-manager.cc
@@ -40,6 +40,8 @@
 #include "rust-extern-crate.h"
 #include "rust-attributes.h"
 #include "rust-early-name-resolver.h"
+#include "rust-attribute-visitor.h"
+#include "rust-expand-visitor.h"
 
 #include "diagnostic.h"
 #include "input.h"
@@ -846,10 +848,9 @@ Session::expansion (AST::Crate &crate)
 
   while (!fixed_point_reached && iterations < cfg.recursion_limit)
     {
-      /* We need to name resolve macros and imports here */
+      AttrVisitor ().go (crate);
       Resolver::EarlyNameResolver ().go (crate);
-
-      expander.expand_crate ();
+      ExpandVisitor (expander).go (crate);
 
       fixed_point_reached = !expander.has_changed ();
       expander.reset_changed_state ();