On Mon, Sep 16, 2013 at 06:04:23PM +0200, Jakub Jelinek wrote: > On Mon, Sep 16, 2013 at 05:59:28PM +0200, Marek Polacek wrote: > > Regtested/ran bootstrap-ubsan on x86_64-linux. > > That looks wrong. ubsan_type_descriptor shouldn't change TYPE_PRECISION of > the type it has been called with, whether type is a bitfield or not can > change what typedescriptor is generated, but not unrelated code.
Ok, that was weird. What about this one? We use the TYPE_SIZE precision if we're dealing with bit-fields, but don't change the type in any way. Ubsan testsuite passes... 2013-09-16 Marek Polacek <pola...@redhat.com> PR sanitizer/58413 * ubsan.c (get_ubsan_type_info_for_type): For bit-fields, use the precision of its TYPE_SIZE. --- gcc/ubsan.c.mp 2013-09-16 18:13:01.075903156 +0200 +++ gcc/ubsan.c 2013-09-16 18:13:20.514974154 +0200 @@ -233,7 +233,13 @@ ubsan_source_location (location_t loc) static unsigned short get_ubsan_type_info_for_type (tree type) { - int prec = exact_log2 (TYPE_PRECISION (type)); + int prec = TYPE_PRECISION (type); + + /* Handle bit-fields. */ + if (compare_tree_int (TYPE_SIZE (type), prec) == 1) + prec = tree_low_cst (TYPE_SIZE (type), 1); + + prec = exact_log2 (prec); if (prec == -1) error ("unexpected size of type %qT", type); Marek