re PR ipa/61659 (Extra undefined symbol because of devirtualization)

	PR c++/61659
	PR c++/61687
Revert:
gcc/c-family/
	* c.opt (-fuse-all-virtuals): New.
gcc/cp/
	* decl2.c (mark_all_virtuals): New variable.
	(maybe_emit_vtables): Check it instead of flag_devirtualize.
	(cp_write_global_declarations): Set it and give helpful diagnostic
	if it introduces errors.
	* class.c (finish_struct_1): Check it.

From-SVN: r213308

3 files changed, 10 insertions, 38 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3d8bf6d..25d9b8a 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,14 @@
 2014-07-30  Jason Merrill  <jason@redhat.com>
 
+	PR c++/61659
+	PR c++/61687
+	Revert:
+	* decl2.c (mark_all_virtuals): New variable.
+	(maybe_emit_vtables): Check it instead of flag_devirtualize.
+	(cp_write_global_declarations): Set it and give helpful diagnostic
+	if it introduces errors.
+	* class.c (finish_struct_1): Check it.
+
 	PR lto/53808
 	PR c++/61659
 	* pt.c (push_template_decl_real): Set DECL_COMDAT on templates.
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 0f611e1..235c68a 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6408,7 +6408,7 @@ finish_struct_1 (tree t)
 	 in every translation unit where the class definition appears.  If
 	 we're devirtualizing, we can look into the vtable even if we
 	 aren't emitting it.  */
-      if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE || flag_use_all_virtuals)
+      if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE)
 	keyed_classes = tree_cons (NULL_TREE, t, keyed_classes);
     }
 
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 884be0a..eafdce5 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -106,11 +106,6 @@ static GTY(()) vec<tree, va_gc> *no_linkage_decls;
 /* Nonzero if we're done parsing and into end-of-file activities.  */
 
 int at_eof;
-
-/* Nonzero if we've instantiated everything used directly, and now want to
-   mark all virtual functions as used so that they are available for
-   devirtualization.  */
-static int mark_all_virtuals;
 
 
 /* Return a member function type (a METHOD_TYPE), given FNTYPE (a
@@ -2020,15 +2015,6 @@ maybe_emit_vtables (tree ctype)
       if (DECL_COMDAT (primary_vtbl)
 	  && CLASSTYPE_DEBUG_REQUESTED (ctype))
 	note_debug_info_needed (ctype);
-      if (mark_all_virtuals && !DECL_ODR_USED (primary_vtbl))
-	{
-	  /* Make sure virtual functions get instantiated/synthesized so that
-	     they can be inlined after devirtualization even if the vtable is
-	     never emitted.  */
-	  mark_used (primary_vtbl);
-	  mark_vtable_entries (primary_vtbl);
-	  return true;
-	}
       return false;
     }
 
@@ -4345,8 +4331,6 @@ cp_write_global_declarations (void)
      instantiated, etc., etc.  */
 
   emit_support_tinfos ();
-  int errs = errorcount + sorrycount;
-  bool explained_devirt = false;
 
   do
     {
@@ -4579,27 +4563,6 @@ cp_write_global_declarations (void)
 					 pending_statics->length ()))
 	reconsider = true;
 
-      if (flag_use_all_virtuals)
-	{
-	  if (!reconsider && !mark_all_virtuals)
-	    {
-	      mark_all_virtuals = true;
-	      reconsider = true;
-	      errs = errorcount + sorrycount;
-	    }
-	  else if (mark_all_virtuals
-		   && !explained_devirt
-		   && (errorcount + sorrycount > errs))
-	    {
-	      inform (global_dc->last_location, "this error is seen due to "
-		      "instantiation of all virtual functions, which the C++ "
-		      "standard says are always considered used; this is done "
-		      "to support devirtualization optimizations, but can be "
-		      "disabled with -fno-use-all-virtuals");
-	      explained_devirt = true;
-	    }
-	}
-
       retries++;
     }
   while (reconsider);