diff mbox

PR debug/16063. Add DW_AT_type to DW_TAG_enumeration.

Message ID 1395859013.5704.170.camel@bordewijk.wildebeest.org
State New
Headers show

Commit Message

Mark Wielaard March 26, 2014, 6:36 p.m. UTC 
On irc Tom Tromey pointed out that the patch generates duplicate base
type DIEs for enums with the same underlying base type. This is because
it was calling base_type_die () and adding the DW_AT_type by hand
instead of calling add_type_attribute () to add it to the enumeration
DIE. The only difference with the original patch is the following:

  {
    tree underlying = lang_hooks.types.enum_underlying_base_type (type);
-   dw_die_ref underlying_die = base_type_die (underlying);
-   add_AT_die_ref (type_die, DW_AT_type, underlying_die);
+   add_type_attribute (type_die, underlying, 0, 0, context_die);
  }

This generates the same DWARF except for generating multiple instances
of the same base type DIE in case multiple enums in a CU share the same
underlying base type.

Comments

Tom Tromey April 10, 2014, 3:56 p.m. UTC | #1 
>>>>> "Mark" == Mark Wielaard <mjw@redhat.com> writes:

Mark> Add a new lang-hook that provides the underlying base type of an
Mark> ENUMERAL_TYPE. Including implementations for C and C++. Use this
Mark> enum_underlying_base_type lang-hook in dwarf2out.c to add a DW_AT_type
Mark> base type reference to a DW_TAG_enumeration.

Just FYI - I sent a patch for gdb to use this information.
I'll probably put it in before the gcc change goes in, on the theory
that when the gcc change goes in, nobody will have to wait to debug.
However it would be nice to be assured that the gcc change is ok in
principle first.

Tom
Cary Coutant April 10, 2014, 5:51 p.m. UTC | #2 
> However it would be nice to be assured that the gcc change is ok in
> principle first.

The DWARF bits are fine with me.

-cary
Mark Wielaard April 11, 2014, 7:55 a.m. UTC | #3 
On Thu, 2014-04-10 at 10:51 -0700, Cary Coutant wrote:
> > However it would be nice to be assured that the gcc change is ok in
> > principle first.
> 
> The DWARF bits are fine with me.

Thanks. Who can approve the other bits?
When approved should I wait till stage 1 opens before committing?

Thanks,

Mark
Cary Coutant April 11, 2014, 6:03 p.m. UTC | #4 
>> 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.

> 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.

-cary
diff mbox

Patch

From 964dcd8a1aefb6bc733372aa42868ed3ad8a46d7 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mjw@redhat.com>
Date: Sun, 23 Mar 2014 12:05:16 +0100
Subject: [PATCH] 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.
---
 gcc/ChangeLog           |   10 ++++++++++
 gcc/c-family/ChangeLog  |    6 ++++++
 gcc/c-family/c-common.c |    8 ++++++++
 gcc/c-family/c-common.h |    1 +
 gcc/c/ChangeLog         |    5 +++++
 gcc/c/c-objc-common.h   |    2 ++
 gcc/cp/ChangeLog        |    6 ++++++
 gcc/cp/cp-lang.c        |   18 ++++++++++++++++++
 gcc/dwarf2out.c         |    6 ++++++
 gcc/langhooks-def.h     |    4 +++-
 gcc/langhooks.h         |    2 ++
 11 files changed, 67 insertions(+), 1 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b456eff..7bce951 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 536b4fc..94d779d 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.
+
 2014-03-22  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/60603
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index abd96fb..55ebbcc 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 1099b10..e378b44 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 b39b7d6..9ab6eab 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.
+
 2014-03-18  Manuel López-Ibáñez  <manu@gcc.gnu.org>
 
 	PR c/55383
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 1acfec3..8dad776 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.
+
 2014-03-21  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/60384
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 af97408..8c045cb 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -17339,6 +17339,12 @@  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.  */
-- 
1.7.1