[PATCH v2 08/20] Remove DW_SIGNATURE

[Tom Tromey]

This removes DW_SIGNATURE in favor of methods on struct attribute.  As
usual, the methods check the form, which DW_SIGNATURE did not do.

gdb/ChangeLog
2020-04-04  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (read_attribute_value, lookup_die_type)
	(dump_die_shallow, follow_die_sig, get_DW_AT_signature_type):
	Update.
	* dwarf2/attribute.h (struct attribute) <as_signature,
	set_signature>: New methods.
	(DW_SIGNATURE): Remove.
---
 gdb/ChangeLog          |  9 +++++++++
 gdb/dwarf2/attribute.h | 16 +++++++++++++++-
 gdb/dwarf2/read.c      | 10 +++++-----
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/gdb/dwarf2/attribute.h b/gdb/dwarf2/attribute.h
index c52212f7b00..4a77e856669 100644
--- a/gdb/dwarf2/attribute.h
+++ b/gdb/dwarf2/attribute.h
@@ -57,6 +57,14 @@ struct attribute
     return u.blk;
   }
 
+  /* Return the signature.  The attribute must have signature
+     form.  */
+  ULONGEST as_signature () const
+  {
+    gdb_assert (form == DW_FORM_ref_sig8);
+    return u.signature;
+  }
+
   /* Return non-zero if ATTR's value is a section offset --- classes
      lineptr, loclistptr, macptr or rangelistptr --- or zero, otherwise.
      You may use DW_UNSND (attr) to retrieve such offsets.
@@ -145,6 +153,13 @@ struct attribute
     u.blk = blk;
   }
 
+  /* Set the signature value for this attribute.  */
+  void set_signature (ULONGEST signature)
+  {
+    gdb_assert (form == DW_FORM_ref_sig8);
+    u.signature = signature;
+  }
+
 
   ENUM_BITFIELD(dwarf_attribute) name : 16;
   ENUM_BITFIELD(dwarf_form) form : 15;
@@ -171,6 +186,5 @@ struct attribute
 #define DW_UNSND(attr)     ((attr)->u.unsnd)
 #define DW_SND(attr)       ((attr)->u.snd)
 #define DW_ADDR(attr)	   ((attr)->u.addr)
-#define DW_SIGNATURE(attr) ((attr)->u.signature)
 
 #endif /* GDB_DWARF2_ATTRIBUTE_H */
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 1de38ef6437..1f4c7b01bcd 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -18549,7 +18549,7 @@ read_attribute_value (const struct die_reader_specs *reader,
       info_ptr += 8;
       break;
     case DW_FORM_ref_sig8:
-      DW_SIGNATURE (attr) = read_8_bytes (abfd, info_ptr);
+      attr->set_signature (read_8_bytes (abfd, info_ptr));
       info_ptr += 8;
       break;
     case DW_FORM_ref_udata:
@@ -20743,7 +20743,7 @@ lookup_die_type (struct die_info *die, const struct attribute *attr,
     }
   else if (attr->form == DW_FORM_ref_sig8)
     {
-      ULONGEST signature = DW_SIGNATURE (attr);
+      ULONGEST signature = attr->as_signature ();
 
       return get_signatured_type (die, signature, cu);
     }
@@ -21436,7 +21436,7 @@ dump_die_shallow (struct ui_file *f, int indent, struct die_info *die)
 	  break;
 	case DW_FORM_ref_sig8:
 	  fprintf_unfiltered (f, "signature: %s",
-			      hex_string (DW_SIGNATURE (&die->attrs[i])));
+			      hex_string (die->attrs[i].as_signature ()));
 	  break;
 	case DW_FORM_string:
 	case DW_FORM_strp:
@@ -22010,7 +22010,7 @@ static struct die_info *
 follow_die_sig (struct die_info *src_die, const struct attribute *attr,
 		struct dwarf2_cu **ref_cu)
 {
-  ULONGEST signature = DW_SIGNATURE (attr);
+  ULONGEST signature = attr->as_signature ();
   struct signatured_type *sig_type;
   struct die_info *die;
 
@@ -22117,7 +22117,7 @@ get_DW_AT_signature_type (struct die_info *die, const struct attribute *attr,
     }
   else if (attr->form == DW_FORM_ref_sig8)
     {
-      return get_signatured_type (die, DW_SIGNATURE (attr), cu);
+      return get_signatured_type (die, attr->as_signature (), cu);
     }
   else
     {
-- 
2.17.2