cp:

	PR c++/20746
	* method.c (use_thunk): Protect covariant pointer return
	adjustments from NULL pointers.
testsuite:
	PR c++/20746
	* g++.dg/abi/covariant5.C: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@97557 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 3 deletions

diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 70d664283bb..9036f64c802 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -470,10 +470,27 @@ use_thunk (tree thunk_fndecl, bool emit_p)
 	finish_expr_stmt (t);
       else
 	{
-	  t = force_target_expr (TREE_TYPE (t), t);
 	  if (!this_adjusting)
-	    t = thunk_adjust (t, /*this_adjusting=*/0,
-			      fixed_offset, virtual_offset);
+	    {
+	      tree cond = NULL_TREE;
+
+	      if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
+		{
+		  /* If the return type is a pointer, we need to
+		     protect against NULL.  We know there will be an
+		     adjustment, because that's why we're emitting a
+		     thunk.  */
+		  t = save_expr (t);
+		  cond = cp_convert (boolean_type_node, t);
+		}
+	      
+	      t = thunk_adjust (t, /*this_adjusting=*/0,
+				fixed_offset, virtual_offset);
+	      if (cond)
+		t = build3 (COND_EXPR, TREE_TYPE (t), cond, t,
+			    cp_convert (TREE_TYPE (t), integer_zero_node));
+	    }
+	  t = force_target_expr (TREE_TYPE (t), t);
 	  finish_return_stmt (t);
 	}