c++: streamline built-in trait addition process

Adding a new built-in trait currently involves manual boilerplate
consisting of defining an rid enumerator for the identifier as well as a
corresponding cp_trait_kind enumerator and handling them in various switch
statements, the exact set of which depends on whether the proposed trait
yields (and thus is recognized as) a type or an expression.

To streamline the process, this patch adds a central cp-trait.def file
that tabulates the essential details about each built-in trait (whether
it yields a type or an expression, its code, its spelling and its arity)
and uses this file to automate away the manual boilerplate.  It also
migrates all the existing C++-specific built-in traits to use this
approach.

After this change, adding a new built-in trait just entails declaring
it in cp-trait.def and defining its behavior in finish_trait_expr/type
(and handling it in diagnose_trait_expr, if it's an expression-yielding
trait).

gcc/c-family/ChangeLog:

	* c-common.cc (c_common_reswords): Use cp/cp-trait.def to handle
	C++ traits.
	* c-common.h (enum rid): Likewise.

gcc/cp/ChangeLog:

	* constraint.cc (diagnose_trait_expr): Likewise.
	* cp-objcp-common.cc (names_builtin_p): Likewise.
	* cp-tree.h (enum cp_trait_kind): Likewise.
	* cxx-pretty-print.cc (pp_cxx_trait): Likewise.
	* parser.cc (cp_keyword_starts_decl_specifier_p): Likewise.
	(cp_parser_primary_expression): Likewise.
	(cp_parser_trait): Likewise.
	(cp_parser_simple_type_specifier): Likewise.
	* cp-trait.def: New file.

1 files changed, 4 insertions, 40 deletions

diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc
index 2d3f206..e4df30d 100644
--- a/gcc/cp/cp-objcp-common.cc
+++ b/gcc/cp/cp-objcp-common.cc
@@ -430,46 +430,10 @@ names_builtin_p (const char *name)
     case RID_BUILTIN_ASSOC_BARRIER:
     case RID_BUILTIN_BIT_CAST:
     case RID_OFFSETOF:
-    case RID_HAS_NOTHROW_ASSIGN:
-    case RID_HAS_NOTHROW_CONSTRUCTOR:
-    case RID_HAS_NOTHROW_COPY:
-    case RID_HAS_TRIVIAL_ASSIGN:
-    case RID_HAS_TRIVIAL_CONSTRUCTOR:
-    case RID_HAS_TRIVIAL_COPY:
-    case RID_HAS_TRIVIAL_DESTRUCTOR:
-    case RID_HAS_UNIQUE_OBJ_REPRESENTATIONS:
-    case RID_HAS_VIRTUAL_DESTRUCTOR:
-    case RID_IS_ABSTRACT:
-    case RID_IS_AGGREGATE:
-    case RID_IS_BASE_OF:
-    case RID_IS_CLASS:
-    case RID_IS_EMPTY:
-    case RID_IS_ENUM:
-    case RID_IS_FINAL:
-    case RID_IS_LAYOUT_COMPATIBLE:
-    case RID_IS_LITERAL_TYPE:
-    case RID_IS_POINTER_INTERCONVERTIBLE_BASE_OF:
-    case RID_IS_POD:
-    case RID_IS_POLYMORPHIC:
-    case RID_IS_SAME_AS:
-    case RID_IS_STD_LAYOUT:
-    case RID_IS_TRIVIAL:
-    case RID_IS_TRIVIALLY_ASSIGNABLE:
-    case RID_IS_TRIVIALLY_CONSTRUCTIBLE:
-    case RID_IS_TRIVIALLY_COPYABLE:
-    case RID_IS_UNION:
-    case RID_IS_ASSIGNABLE:
-    case RID_IS_CONSTRUCTIBLE:
-    case RID_IS_NOTHROW_ASSIGNABLE:
-    case RID_IS_NOTHROW_CONSTRUCTIBLE:
-    case RID_UNDERLYING_TYPE:
-    case RID_IS_CONVERTIBLE:
-    case RID_IS_NOTHROW_CONVERTIBLE:
-    case RID_REF_CONSTRUCTS_FROM_TEMPORARY:
-    case RID_REF_CONVERTS_FROM_TEMPORARY:
-    case RID_REMOVE_CV:
-    case RID_REMOVE_REFERENCE:
-    case RID_REMOVE_CVREF:
+#define DEFTRAIT(TCC, CODE, NAME, ARITY) \
+    case RID_##CODE:
+#include "cp-trait.def"
+#undef DEFTRAIT
       return true;
     default:
       break;