From 3bf5dcea0935b280189d04c34e84e46fb07f87e7 Mon Sep 17 00:00:00 2001
From: Xavier Leroy <xavier.leroy@inria.fr>
Date: Fri, 17 Aug 2018 10:58:05 +0200
Subject: Check for bit-fields in __builtin_offsetof

__builtin_offsetof(struct s, f) is an error if f is a bit-field.
---
 cparser/Elab.ml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/cparser/Elab.ml b/cparser/Elab.ml
index 5f785c04..668b65d8 100644
--- a/cparser/Elab.ml
+++ b/cparser/Elab.ml
@@ -1839,7 +1839,10 @@ let elab_expr ctx loc env a =
       | _ -> fatal_error "request for member '%s' in something not a structure or union" mem in
     let rec offset_of_list acc env ty = function
       | [] -> acc,ty
-      | fld::rest -> let off = offsetof env ty fld in
+      | fld::rest -> 
+        if fld.fld_bitfield <> None then
+          error "cannot compute offset of bit-field '%s'" fld.fld_name;
+        let off = offsetof env ty fld in
         offset_of_list (acc+off) env fld.fld_typ rest in
     let offset_of_member (env,off_accu,ty) mem =
       match mem,unroll env ty with
-- 
cgit