PR debug/16063. Add DW_AT_type to DW_TAG_enumeration.

Add a new lang-hook that provides the underlying base type of an
ENUMERAL_TYPE. The default implementation will just use type_for_size.
The implementation for C++ will use the ENUM_UNDERLYING_TYPE if it exists.
Use this enum_underlying_base_type lang-hook in dwarf2out.c to add a
DW_AT_type base type reference to a DW_TAG_enumeration.

gcc/
	* dwarf2out.c (gen_enumeration_type_die): Add DW_AT_type if DWARF
	version >= 3 or not strict DWARF.
	* langhooks.h (struct lang_hooks_for_types): Add
	enum_underlying_base_type.
	* langhooks.c (lhd_enum_underlying_base_type): New function.
	* gcc/langhooks.h (struct lang_hooks_for_types): Add
	enum_underlying_base_type.
	* langhooks-def.h (lhd_enum_underlying_base_type): New declaration.
	(LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): New define.
	(LANG_HOOKS_FOR_TYPES_INITIALIZER): Add new lang hook.

gcc/cp/
	* cp-lang.c (cxx_enum_underlying_base_type): New function.
	(LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): Define.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@210717 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 0 deletions

diff --git a/gcc/cp/cp-lang.c b/gcc/cp/cp-lang.c
index c28c07a9d1f..014f393ecfa 100644
--- a/gcc/cp/cp-lang.c
+++ b/gcc/cp/cp-lang.c
@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "tm.h"
 #include "tree.h"
+#include "stor-layout.h"
 #include "cp-tree.h"
 #include "c-family/c-common.h"
 #include "langhooks.h"
@@ -40,6 +41,7 @@ static enum classify_record cp_classify_record (tree type);
 static tree cp_eh_personality (void);
 static tree get_template_innermost_arguments_folded (const_tree);
 static tree get_template_argument_pack_elems_folded (const_tree);
+static tree cxx_enum_underlying_base_type (const_tree);
 
 /* Lang hooks common to C++ and ObjC++ are declared in cp/cp-objcp-common.h;
    consequently, there should be very few hooks below.  */
@@ -81,6 +83,8 @@ static tree get_template_argument_pack_elems_folded (const_tree);
 #define LANG_HOOKS_EH_PERSONALITY cp_eh_personality
 #undef LANG_HOOKS_EH_RUNTIME_TYPE
 #define LANG_HOOKS_EH_RUNTIME_TYPE build_eh_type_type
+#undef LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE
+#define LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE cxx_enum_underlying_base_type
 
 /* Each front end provides its own lang hook initializer.  */
 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
@@ -219,5 +223,21 @@ get_template_argument_pack_elems_folded (const_tree t)
   return fold_cplus_constants (get_template_argument_pack_elems (t));
 }
 
+/* The C++ version of the enum_underlying_base_type langhook.
+   See also cp/semantics.c (finish_underlying_type).  */
+
+static
+tree cxx_enum_underlying_base_type (const_tree type)
+{
+  tree underlying_type = ENUM_UNDERLYING_TYPE (type);
+
+  if (! ENUM_FIXED_UNDERLYING_TYPE_P (type))
+    underlying_type
+      = c_common_type_for_mode (TYPE_MODE (underlying_type),
+                                TYPE_UNSIGNED (underlying_type));
+
+  return underlying_type;
+}
+
 #include "gt-cp-cp-lang.h"
 #include "gtype-cp.h"