PR c++/67942 - diagnose placement new buffer overflow

[gcc.git] / gcc / cp / init.c

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 7600363447d1f50acc60021425d61e89571272b1..7386499d570936479970d80dc2aa0780db5f7ce0 100644 (file)
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2384,20 +2384,26 @@ warn_placement_new_too_small (tree type, tree nelts, tree size, tree oper)
       /* Treat members of unions and members of structs uniformly, even
         though the size of a member of a union may be viewed as extending
         to the end of the union itself (it is by __builtin_object_size).  */
-      if (TREE_CODE (oper) == VAR_DECL || use_obj_size)
+      if ((TREE_CODE (oper) == VAR_DECL || use_obj_size)
+         && DECL_SIZE_UNIT (oper))
        {
          /* Use the size of the entire array object when the expression
             refers to a variable or its size depends on an expression
             that's not a compile-time constant.  */
-         bytes_avail = tree_to_shwi (DECL_SIZE_UNIT (oper));
+         bytes_avail = tree_to_uhwi (DECL_SIZE_UNIT (oper));
          exact_size = !use_obj_size;
        }
-      else
+      else if (TYPE_SIZE_UNIT (TREE_TYPE (oper)))
        {
          /* Use the size of the type of the destination buffer object
             as the optimistic estimate of the available space in it.  */
          bytes_avail = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (oper)));
        }
+      else
+       {
+         /* Bail if neither the size of the object nor its type is known.  */
+         return;
+       }
 
       /* Avoid diagnosing flexible array members (accepted as an extension
         and diagnosed with -Wpedantic).