[libcxx] r257368 - Preemptively disable unsigned integer sanitization in 32 and 64 bit versions of __murmur2_or_cityhash. This lets people use the unsigned integer overflow checker in UBSAN w/o getting hits from libc++'s hash code (where the unsigned integer overflow is legal and deliberate)> Patch by @danielaustin. Reviewed as: http://reviews.llvm.org/D15973

[Marshall Clow via cfe-commits]

Author: marshall
Date: Mon Jan 11 13:27:10 2016
New Revision: 257368

URL: http://llvm.org/viewvc/llvm-project?rev=257368&view=rev
Log:
Preemptively disable unsigned integer sanitization in 32 and 64 bit versions of __murmur2_or_cityhash. This lets people use the unsigned integer overflow checker in UBSAN w/o getting hits from libc++'s hash code (where the unsigned integer overflow is legal and deliberate)> Patch by @danielaustin. Reviewed as: http://reviews.llvm.org/D15973

Modified:
    libcxx/trunk/include/__config
    libcxx/trunk/include/memory

Modified: libcxx/trunk/include/__config
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__config?rev=257368&r1=257367&r2=257368&view=diff
==============================================================================
--- libcxx/trunk/include/__config (original)
+++ libcxx/trunk/include/__config Mon Jan 11 13:27:10 2016
@@ -597,6 +597,11 @@ namespace std {
 
 #define _LIBCPP_HAS_NO_ASAN
 
+// Allow for build-time disabling of unsigned integer sanitization
+#ifndef _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute((no_sanitize("unsigned integer")))
+#endif 
+
 #endif // __clang__ || __GNUC__ || _MSC_VER || __IBMCPP__
 
 #ifndef _LIBCPP_HAS_NO_NOEXCEPT
@@ -826,6 +831,10 @@ extern "C" void __sanitizer_annotate_con
 #define _LIBCPP_HAS_NO_ATOMIC_HEADER
 #endif
 
+#ifndef _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+#endif 
+
 #endif // __cplusplus
 
 #endif // _LIBCPP_CONFIG

Modified: libcxx/trunk/include/memory
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/memory?rev=257368&r1=257367&r2=257368&view=diff
==============================================================================
--- libcxx/trunk/include/memory (original)
+++ libcxx/trunk/include/memory Mon Jan 11 13:27:10 2016
@@ -3194,7 +3194,7 @@ struct __murmur2_or_cityhash<_Size, 32>
 // murmur2
 template <class _Size>
 _Size
-__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
+__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len) _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK 
 {
     const _Size __m = 0x5bd1e995;
     const _Size __r = 24;
@@ -3344,7 +3344,7 @@ struct __murmur2_or_cityhash<_Size, 64>
 // cityhash64
 template <class _Size>
 _Size
-__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
+__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len) _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK 
 {
   const char* __s = static_cast<const char*>(__key);
   if (__len <= 32) {