From b5260d5134fd57b0b07edf2605b33047dc1406e0 Mon Sep 17 00:00:00 2001 From: Ahmad Fatoum Date: Thu, 15 Oct 2020 11:00:56 +0200 Subject: Revert "common: ubsan: ignore shifting one into sign bit" With the previous commit, we now explicitly tell GCC not to optimize constructs like (1 << 31) under assumption that they are undefined anyway. GCC >= 8.0 -fsanitize=undefined should now not warn any longer about (1 << 31) instances, so remove our work around. This reverts commit 55397b9ebe3a21a3aeb6a98131c0991bff0f7123. Signed-off-by: Ahmad Fatoum Signed-off-by: Sascha Hauer --- lib/ubsan.c | 20 -------------------- 1 file changed, 20 deletions(-) diff --git a/lib/ubsan.c b/lib/ubsan.c index 085d470cf7..648c7cc48a 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -382,26 +382,6 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, if (suppress_report(&data->location)) return; - /* This handler would be called for code shifting a one into the - * sign bit like (1 << 31), which is all too common in barebox. - * It's technically UB, but it's so prevalent that it's highly - * unlikely to be treated by a compiler as anything else than the - * standard-compliant (1U << 31). Thus check for this case here - * and ignore it selectively - */ - if (type_is_signed(lhs_type)) { - s_max lhs_int, rhs_int; - - lhs_int = get_signed_val(lhs_type, lhs); - rhs_int = get_signed_val(rhs_type, rhs); - - if (fls(lhs_int) + rhs_int == type_bit_width(lhs_type)) { - pr_debug("signed left shift of %lld by %lld ignored.\n", - (s64)lhs_int, (s64)rhs_int); - return; - } - } - ubsan_prologue(&data->location, &flags); val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); -- cgit v1.2.3