[PATCH 18/20] Add attribute::virtuality method

[Tom Tromey <tom@tromey.com>]

This adds a new attribute::virtuality method and changes the DWARF
reader to use it.  This also ensures that the attibute's form will now
be respected.

2020-03-28  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (dwarf2_add_field, dwarf2_add_member_fn): Update.
	* dwarf2/attribute.h (struct attribute) <virtuality>: New method.
	* dwarf2/attribute.c (attribute::virtuality): New method.
---
 gdb/ChangeLog          |  6 ++++++
 gdb/dwarf2/attribute.c | 21 +++++++++++++++++++++
 gdb/dwarf2/attribute.h |  5 +++++
 gdb/dwarf2/read.c      |  4 ++--
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/gdb/dwarf2/attribute.c b/gdb/dwarf2/attribute.c
index ee5e6321bde..7f428279757 100644
--- a/gdb/dwarf2/attribute.c
+++ b/gdb/dwarf2/attribute.c
@@ -240,3 +240,24 @@ attribute::defaulted () const
 	       plongest (value));
   return DW_DEFAULTED_no;
 }
+
+/* See attribute.h.  */
+
+dwarf_virtuality_attribute
+attribute::virtuality () const
+{
+  LONGEST value = constant_value (-1);
+
+  switch (value)
+    {
+    case DW_VIRTUALITY_none:
+    case DW_VIRTUALITY_virtual:
+    case DW_VIRTUALITY_pure_virtual:
+      return (dwarf_virtuality_attribute) value;
+    }
+
+  if (form_is_constant ())
+    complaint (_("unrecognized DW_AT_virtuality value (%s)"),
+	       plongest (value));
+  return DW_VIRTUALITY_none;
+}
diff --git a/gdb/dwarf2/attribute.h b/gdb/dwarf2/attribute.h
index dce93b154a8..7c0ce1615cf 100644
--- a/gdb/dwarf2/attribute.h
+++ b/gdb/dwarf2/attribute.h
@@ -237,6 +237,11 @@ struct attribute
      returned.  */
   dwarf_defaulted_attribute defaulted () const;
 
+  /* Return the attribute's value as a dwarf_virtuality_attribute
+     constant according to DWARF spec.  An unrecognized value will
+     issue a complaint and return DW_VIRTUALITY_none.  */
+  dwarf_virtuality_attribute virtuality () const;
+
 
   ENUM_BITFIELD(dwarf_attribute) name : 15;
 
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index ec4e6e2e3b4..66a508c95ea 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -14107,7 +14107,7 @@ dwarf2_add_field (struct field_info *fip, struct die_info *die,
 
   attr = dwarf2_attr (die, DW_AT_virtuality, cu);
   if (attr != nullptr)
-    new_field->virtuality = DW_UNSND (attr);
+    new_field->virtuality = attr->virtuality ();
   else
     new_field->virtuality = DW_VIRTUALITY_none;
 
@@ -14661,7 +14661,7 @@ dwarf2_add_member_fn (struct field_info *fip, struct die_info *die,
   else
     {
       attr = dwarf2_attr (die, DW_AT_virtuality, cu);
-      if (attr && DW_UNSND (attr))
+      if (attr != nullptr && attr->virtuality () != DW_VIRTUALITY_none)
 	{
 	  /* GCC does this, as of 2008-08-25; PR debug/37237.  */
 	  complaint (_("Member function \"%s\" (offset %s) is virtual "
-- 
2.17.2