From f0786cf087d6740f281b7b8093066a47a706d29a Mon Sep 17 00:00:00 2001 From: Filipe Cabecinhas Date: Mon, 16 Jul 2018 13:41:54 +0000 Subject: [cfi] Don't pass a uint16_t to memset. Make sure the 16-bit constant is appropriate for us. Reviewers: eugenis, pcc, kcc Subscribers: delcypher, #sanitizers, llvm-commits Differential Revision: https://reviews.llvm.org/D49252 git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@337170 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/cfi/cfi.cc | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/cfi/cfi.cc b/lib/cfi/cfi.cc index 52f504bd2..5ee836569 100644 --- a/lib/cfi/cfi.cc +++ b/lib/cfi/cfi.cc @@ -132,7 +132,10 @@ void ShadowBuilder::Start() { void ShadowBuilder::AddUnchecked(uptr begin, uptr end) { uint16_t *shadow_begin = MemToShadow(begin, shadow_); uint16_t *shadow_end = MemToShadow(end - 1, shadow_) + 1; - memset(shadow_begin, kUncheckedShadow, + // memset takes a byte, so our unchecked shadow value requires both bytes to + // be the same. Make sure we're ok during compilation. + static_assert(kUncheckedShadow & 0xff == ((kUncheckedShadow >> 8) & 0xff)); + memset(shadow_begin, kUncheckedShadow & 0xff, (shadow_end - shadow_begin) * sizeof(*shadow_begin)); } -- cgit v1.2.3