Bug 29686 - Fix testing the presence of anonymous data member in a struct

* include/abg-fwd.h (anonymous_data_member_to_class_or_union): Add
	a new overload.
	(anonymous_data_member_exists_in_class): Declare new function.
	* src/abg-dwarf-reader.cc (add_or_update_class_type): Use the new
	anonymous_data_member_exists_in_class function.
	* src/abg-ir.cc (anonymous_data_member_to_class_or_union): Define
	new function.
	* tests/data/test-read-dwarf/test-libandroid.so.abi: Adjust.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

include/abg-fwd.h

@@ -727,6 +727,13 @@ anonymous_data_member_to_class_or_union(const var_decl*);
 class_or_union_sptr
 anonymous_data_member_to_class_or_union(const var_decl_sptr&);
 
+class_or_union_sptr
+anonymous_data_member_to_class_or_union(const var_decl&);
+
+bool
+anonymous_data_member_exists_in_class(const var_decl& anon_dm,
+				      const class_or_union& clazz);
+
 bool
 scope_anonymous_or_typedef_named(const decl_base&);
 

src/abg-dwarf-reader.cc

@@ -13138,7 +13138,8 @@ add_or_update_class_type(reader&	 rdr,
 	      die_access_specifier(&child, access);
 
 	      var_decl_sptr dm(new var_decl(n, t, loc, m));
-	      if (n.empty() && result->find_data_member(dm))
+	      if (n.empty()
+		  && anonymous_data_member_exists_in_class(*dm, *result))
 		// dm is an anonymous data member that was already
 		// present in the current class so let's not add it.
 		continue;

src/abg-ir.cc

@@ -5951,6 +5951,20 @@ anonymous_data_member_to_class_or_union(const var_decl* d)
   return 0;
 }
 
+/// Get the @ref class_or_union type of a given anonymous data member.
+///
+/// @param d the anonymous data member to consider.
+///
+/// @return the @ref class_or_union type of the anonymous data member
+/// @p d.
+class_or_union_sptr
+anonymous_data_member_to_class_or_union(const var_decl& d)
+{
+  if (is_anonymous_data_member(d))
+    return is_class_or_union_type(d.get_type());
+  return class_or_union_sptr();
+}
+
 /// Test if a data member has annonymous type or not.
 ///
 /// @param d the data member to consider.
@@ -6006,6 +6020,48 @@ anonymous_data_member_to_class_or_union(const var_decl_sptr &d)
   return class_or_union_sptr();
 }
 
+/// Test if a given anonymous data member exists in a class or union.
+///
+/// @param anon_dm the anonymous data member to consider.
+///
+/// @param clazz the class to consider.
+///
+/// @return true iff @p anon_dm exists in the @clazz.
+bool
+anonymous_data_member_exists_in_class(const var_decl& anon_dm,
+				      const class_or_union& clazz)
+{
+  if (!anon_dm.get_is_anonymous()
+      || !is_class_or_union_type(anon_dm.get_type()))
+    return false;
+
+  class_or_union_sptr cl = is_class_or_union_type(anon_dm.get_type());
+  ABG_ASSERT(cl);
+
+  // Look for the presence of each data member of anon_dm in clazz.
+  //
+  // If one data member of anon_dm is not present in clazz, then the
+  // data member anon_dm is considered to not exist in clazz.
+  for (auto anon_dm_m : cl->get_non_static_data_members())
+    {
+      // If the data member anon_dm_m is not an anonymous data member,
+      // it's easy to look for it.
+      if (!is_anonymous_data_member(anon_dm_m))
+	{
+	  if (!clazz.find_data_member(anon_dm_m->get_name()))
+	    return false;
+	}
+      // If anon_dm_m is itself an anonymous data member then recurse
+      else
+	{
+	  if (!anonymous_data_member_exists_in_class(*anon_dm_m, clazz))
+	    return false;
+	}
+    }
+
+  return true;
+}
+
 /// Test if the scope of a given decl is anonymous or anonymous with a
 /// naming typedef.
 ///

tests/data/test-read-dwarf/test-libandroid.so.abi

@@ -11061,9 +11061,6 @@
               <data-member access='public' layout-offset-in-bits='16'>
                 <var-decl name='__data_' type-id='72631341' visibility='default' filepath='external/libcxx/include/string' line='761' column='1'/>
               </data-member>
-              <data-member access='public' layout-offset-in-bits='0'>
-                <var-decl name='' type-id='ac5ab59f' visibility='default' filepath='external/libcxx/include/string' line='756' column='1'/>
-              </data-member>
             </class-decl>
           </member-type>
           <member-type access='private'>