Re: [PATCH] PR debug/16063. Add DW_AT_type to DW_TAG_enumeration.

[Mark Wielaard <mjw at redhat dot com>]

On Fri, 2014-04-11 at 11:03 -0700, Cary Coutant wrote:
> >> The DWARF bits are fine with me.
> >
> > Thanks. Who can approve the other bits?
> 
> You should probably get C and C++ front end approval. I'm not really
> sure who needs to review patches in c-family/. Since the part in c/ is
> so tiny, maybe all you need is a C++ front end maintainer. Both
> Richard Henderson and Jason Merrill are global reviewers, so either of
> them could approve the whole thing.

Thanks, I added them to the CC.

> > When approved should I wait till stage 1 opens before committing?
> 
> Yes. The PR you're fixing is an enhancement request, not a regression,
> so it needs to wait.

Since stage one just opened up again this seems a good time to re-ask
for approval then :) Rebased patch against current trunk attached.

Thanks,

Mark


commit a5044d478738e2fbd471b8b9d98e1b37e5d8b64b
Author: Mark Wielaard <mjw@redhat.com>
Date:   Sun Mar 23 12:05:16 2014 +0100

    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. Including implementations for C and C++. 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
    	enum_underlying_base_type defined and DWARF version > 3.
    	* langhooks.h (struct lang_hooks_for_types): Add
    	enum_underlying_base_type.
    	* langhooks-def.h (LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): New define.
    	(LANG_HOOKS_FOR_TYPES_INITIALIZER): Add new lang hook.
    
    gcc/c-family/
    	* c-common.c (c_enum_underlying_base_type): New function.
    	* c-common.h (c_enum_underlying_base_type): Add declaration.
    
    gcc/c/
    	* c-objc-common.h (LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): Define.
    
    gcc/cp/
    	* cp-lang.c (cxx_enum_underlying_base_type): New function.
    	(LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): Define.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 355ba29..2a8f3ee 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2014-03-21  Mark Wielaard  <mjw@redhat.com>
 
+	PR debug/16063
+	* dwarf2out.c (gen_enumeration_type_die): Add DW_AT_type if
+	enum_underlying_base_type defined and DWARF version > 3.
+	* langhooks.h (struct lang_hooks_for_types): Add
+	enum_underlying_base_type.
+	* langhooks-def.h (LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): New define.
+	(LANG_HOOKS_FOR_TYPES_INITIALIZER): Add new lang hook.
+
+2014-03-21  Mark Wielaard  <mjw@redhat.com>
+
 	* dwarf2out.c (gen_enumeration_type_die): Add DW_AT_const_value
 	as unsigned or int depending on type and value used.
 
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 206b47b..0b7b7e1 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,9 @@
+2014-03-21  Mark Wielaard  <mjw@redhat.com>
+
+	PR debug/16063
+	* c-common.c (c_enum_underlying_base_type): New function.
+	* c-common.h (c_enum_underlying_base_type): Add declaration.
+
 2014-04-14  Richard Biener  <rguenther@suse.de>
 	Marc Glisse  <marc.glisse@inria.fr>
 
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index c0e247b..a7c212f 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -3902,6 +3902,14 @@ c_register_builtin_type (tree type, const char* name)
 
   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
 }
+
+/* The C version of the enum_underlying_base_type langhook.  */
+tree
+c_enum_underlying_base_type (const_tree type)
+{
+  return c_common_type_for_size (TYPE_PRECISION (type), TYPE_UNSIGNED (type));
+}
+
 
 /* Print an error message for invalid operands to arith operation
    CODE with TYPE0 for operand 0, and TYPE1 for operand 1.
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 24959d8..d433972 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -832,6 +832,7 @@ extern void c_common_finish (void);
 extern void c_common_parse_file (void);
 extern alias_set_type c_common_get_alias_set (tree);
 extern void c_register_builtin_type (tree, const char*);
+extern tree c_enum_underlying_base_type (const_tree);
 extern bool c_promoting_integer_type_p (const_tree);
 extern int self_promoting_args_p (const_tree);
 extern tree strip_pointer_operator (tree);
diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index bacfbe3..cf4252b 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-21  Mark Wielaard  <mjw@redhat.com>
+
+	PR debug/16063
+	* c-objc-common.h (LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): Define.
+
 2014-04-12  Igor Zamyatin  <igor.zamyatin@intel.com>
 
 	PR middle-end/60469
diff --git a/gcc/c/c-objc-common.h b/gcc/c/c-objc-common.h
index 92cf60f..0651db7 100644
--- a/gcc/c/c-objc-common.h
+++ b/gcc/c/c-objc-common.h
@@ -84,6 +84,8 @@ along with GCC; see the file COPYING3.  If not see
 #define LANG_HOOKS_TO_TARGET_CHARSET c_common_to_target_charset
 #undef LANG_HOOKS_EXPR_TO_DECL
 #define LANG_HOOKS_EXPR_TO_DECL c_expr_to_decl
+#undef LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE
+#define LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE c_enum_underlying_base_type
 
 /* The C front end's scoping structure is very different from
    that expected by the language-independent code; it is best
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9510587..46308cb 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2014-03-21  Mark Wielaard  <mjw@redhat.com>
+
+	PR debug/16063
+	* cp-lang.c (cxx_enum_underlying_base_type): New function.
+	(LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE): Define.
+
 2014-04-14  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* cp-tree.h (TYPE_IDENTIFIER): Remove declaration.
diff --git a/gcc/cp/cp-lang.c b/gcc/cp/cp-lang.c
index c28c07a..6a40d29 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 +223,19 @@ 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"
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index d4e4b17..e71fce6 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -17344,6 +17344,12 @@ gen_enumeration_type_die (tree type, dw_die_ref context_die)
 
       TREE_ASM_WRITTEN (type) = 1;
       add_byte_size_attribute (type_die, type);
+      if (lang_hooks.types.enum_underlying_base_type != NULL
+	  && (dwarf_version >= 3 || !dwarf_strict))
+	{
+	  tree underlying = lang_hooks.types.enum_underlying_base_type (type);
+	  add_type_attribute (type_die, underlying, 0, 0, context_die);
+	}
       if (TYPE_STUB_DECL (type) != NULL_TREE)
 	{
 	  add_src_coords_attributes (type_die, TYPE_STUB_DECL (type));
diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h
index 95bd379..b8e0d97 100644
--- a/gcc/langhooks-def.h
+++ b/gcc/langhooks-def.h
@@ -173,6 +173,7 @@ extern tree lhd_make_node (enum tree_code);
 #define LANG_HOOKS_GET_SUBRANGE_BOUNDS	NULL
 #define LANG_HOOKS_DESCRIPTIVE_TYPE	NULL
 #define LANG_HOOKS_RECONSTRUCT_COMPLEX_TYPE reconstruct_complex_type
+#define LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE NULL
 
 #define LANG_HOOKS_FOR_TYPES_INITIALIZER { \
   LANG_HOOKS_MAKE_TYPE, \
@@ -191,7 +192,8 @@ extern tree lhd_make_node (enum tree_code);
   LANG_HOOKS_GET_ARRAY_DESCR_INFO, \
   LANG_HOOKS_GET_SUBRANGE_BOUNDS, \
   LANG_HOOKS_DESCRIPTIVE_TYPE, \
-  LANG_HOOKS_RECONSTRUCT_COMPLEX_TYPE \
+  LANG_HOOKS_RECONSTRUCT_COMPLEX_TYPE, \
+  LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE \
 }
 
 /* Declaration hooks.  */
diff --git a/gcc/langhooks.h b/gcc/langhooks.h
index c848b0c..667298b 100644
--- a/gcc/langhooks.h
+++ b/gcc/langhooks.h
@@ -137,6 +137,8 @@ struct lang_hooks_for_types
      return values from functions.  The argument TYPE is the top of the
      chain, and BOTTOM is the new type which we will point to.  */
   tree (*reconstruct_complex_type) (tree, tree);
+
+  tree (*enum_underlying_base_type) (const_tree);
 };
 
 /* Language hooks related to decls and the symbol table.  */