Add feature gate for "rustc_attri".

This commit implemented a basic feature gate to check some attributes
for `rustc_attri`.

gcc/rust/ChangeLog:

	* checks/errors/rust-feature-gate.cc: Add implementations
	for `rustc_attri`.
	* checks/errors/rust-feature-gate.h: Likewise.

gcc/testsuite/ChangeLog:

	* rust/compile/builtin_macro_compile_error.rs: Add
	crate feature `rustc_attri`.
	* rust/compile/builtin_macro_concat.rs: Likewise.
	* rust/compile/builtin_macro_eager1.rs: Likewise.
	* rust/compile/builtin_macro_eager2.rs: Likewise.
	* rust/compile/builtin_macro_env.rs: Likewise.
	* rust/compile/builtin_macro_include_bytes.rs:
	Likewise.
	* rust/compile/builtin_macro_include_str.rs:
	Likewise.
	* rust/compile/builtin_macro_not_found.rs:
	Likewise.
	* rust/compile/builtin_macro_recurse2.rs:
	Likewise.
	* rust/compile/feature_rust_attri0.rs:New file.
	* rust/compile/feature_rust_attri1.rs:New file.
	* rust/compile/include_empty.rs:Add crate feature
	`rustc_attri`.
	* rust/compile/issue-1830_bytes.rs:Likewise.
	* rust/compile/issue-1830_str.rs:Likewise.
	* rust/compile/macro42.rs:Likewise.
	* rust/execute/torture/builtin_macro_cfg.rs:
	Likewise.
	* rust/execute/torture/builtin_macro_concat.rs:
	Likewise.
	* rust/execute/torture/builtin_macro_env.rs:
	Likewise.
	* rust/execute/torture/builtin_macro_include_bytes.rs:
	Likewise.
	* rust/execute/torture/builtin_macro_include_str.rs:
	Likewise.
	* rust/execute/torture/builtin_macro_line.rs:
	Likewise.
	* rust/execute/torture/builtin_macros1.rs:
	Likewise.
	* rust/execute/torture/builtin_macros3.rs:
	Likewise.
	* rust/execute/torture/macros29.rs:Likewise.
	* rust/execute/torture/macros30.rs:Likewise.
	* rust/execute/torture/macros31.rs:Likewise.

Signed-off-by: Xiao Ma <mxlol233@outlook.com>

2 files changed, 56 insertions, 7 deletions

diff --git a/gcc/rust/checks/errors/rust-feature-gate.cc b/gcc/rust/checks/errors/rust-feature-gate.cc
index bd01b52..9b2f025 100644
--- a/gcc/rust/checks/errors/rust-feature-gate.cc
+++ b/gcc/rust/checks/errors/rust-feature-gate.cc
@@ -105,4 +105,54 @@ FeatureGate::visit (AST::ExternBlock &block)
     }
 }
 
+void
+FeatureGate::check_rustc_attri (const std::vector<AST::Attribute> &attributes)
+{
+  for (const AST::Attribute &attr : attributes)
+    {
+      auto name = attr.get_path ().as_string ();
+      if (name.rfind ("rustc_", 0) == 0)
+	{
+	  gate (Feature::Name::RUSTC_ATTRS, attr.get_locus (),
+		"internal implementation detail");
+	}
+    }
+}
+
+void
+FeatureGate::visit (AST::MacroRulesDefinition &rules_def)
+{
+  check_rustc_attri (rules_def.get_outer_attrs ());
+}
+
+void
+FeatureGate::visit (AST::InherentImpl &impl)
+{
+  for (const auto &item : impl.get_impl_items ())
+    {
+      item->accept_vis (*this);
+    }
+}
+
+void
+FeatureGate::visit (AST::TraitImpl &impl)
+{
+  for (const auto &item : impl.get_impl_items ())
+    {
+      item->accept_vis (*this);
+    }
+}
+
+void
+FeatureGate::visit (AST::Method &method)
+{
+  check_rustc_attri (method.get_outer_attrs ());
+}
+
+void
+FeatureGate::visit (AST::Function &function)
+{
+  check_rustc_attri (function.get_outer_attrs ());
+}
+
 } // namespace Rust
\ No newline at end of file
diff --git a/gcc/rust/checks/errors/rust-feature-gate.h b/gcc/rust/checks/errors/rust-feature-gate.h
index 20af147..2bdf419 100644
--- a/gcc/rust/checks/errors/rust-feature-gate.h
+++ b/gcc/rust/checks/errors/rust-feature-gate.h
@@ -25,8 +25,6 @@
 
 namespace Rust {
 
-struct Feature;
-
 class FeatureGate : public AST::ASTVisitor
 {
 public:
@@ -109,14 +107,14 @@ public:
   void visit (AST::TypeParam &param) override {}
   void visit (AST::LifetimeWhereClauseItem &item) override {}
   void visit (AST::TypeBoundWhereClauseItem &item) override {}
-  void visit (AST::Method &method) override {}
+  void visit (AST::Method &method) override;
   void visit (AST::Module &module) override {}
   void visit (AST::ExternCrate &crate) override {}
   void visit (AST::UseTreeGlob &use_tree) override {}
   void visit (AST::UseTreeList &use_tree) override {}
   void visit (AST::UseTreeRebind &use_tree) override {}
   void visit (AST::UseDeclaration &use_decl) override {}
-  void visit (AST::Function &function) override {}
+  void visit (AST::Function &function) override;
   void visit (AST::TypeAlias &type_alias) override {}
   void visit (AST::StructStruct &struct_item) override {}
   void visit (AST::TupleStruct &tuple_struct) override {}
@@ -133,15 +131,15 @@ public:
   void visit (AST::TraitItemConst &item) override {}
   void visit (AST::TraitItemType &item) override {}
   void visit (AST::Trait &trait) override {}
-  void visit (AST::InherentImpl &impl) override {}
-  void visit (AST::TraitImpl &impl) override {}
+  void visit (AST::InherentImpl &impl) override;
+  void visit (AST::TraitImpl &impl) override;
   void visit (AST::ExternalStaticItem &item) override {}
   void visit (AST::ExternalFunctionItem &item) override {}
   void visit (AST::ExternBlock &block) override;
   void visit (AST::MacroMatchFragment &match) override {}
   void visit (AST::MacroMatchRepetition &match) override {}
   void visit (AST::MacroMatcher &matcher) override {}
-  void visit (AST::MacroRulesDefinition &rules_def) override {}
+  void visit (AST::MacroRulesDefinition &rules_def) override;
   void visit (AST::MacroInvocation &macro_invoc) override {}
   void visit (AST::MetaItemPath &meta_item) override {}
   void visit (AST::MetaItemSeq &meta_item) override {}
@@ -191,6 +189,7 @@ public:
 
 private:
   void gate (Feature::Name name, Location loc, const std::string &error_msg);
+  void check_rustc_attri (const std::vector<AST::Attribute> &attributes);
   std::set<Feature::Name> valid_features;
 };
 } // namespace Rust