Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -497,82 +497,115 @@
 if (SANITIZER_COMMON_SUPPORTED_ARCH AND NOT LLVM_USE_SANITIZER AND
     (OS_NAME MATCHES "Android|Darwin|Linux|FreeBSD" OR
     (OS_NAME MATCHES "Windows" AND MSVC)))
-  set(COMPILER_RT_HAS_SANITIZER_COMMON TRUE)
+  set(COMPILER_RT_HAS_SANITIZER_COMMON_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_SANITIZER_COMMON FALSE)
+  set(COMPILER_RT_HAS_SANITIZER_COMMON_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_SANITIZER_COMMON
+  "Enable common sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_SANITIZER_COMMON_DEFAULT})
+
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND
     (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
-  set(COMPILER_RT_HAS_INTERCEPTION TRUE)
+  set(COMPILER_RT_HAS_INTERCEPTION_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_INTERCEPTION FALSE)
+  set(COMPILER_RT_HAS_INTERCEPTION_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_INTERCEPTION
+  "Enable interception (Defaults based on system support)"
+  ${COMPILER_RT_HAS_INTERCEPTION_DEFAULT})
+
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND ASAN_SUPPORTED_ARCH AND
     (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
-  set(COMPILER_RT_HAS_ASAN TRUE)
+  set(COMPILER_RT_HAS_ASAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_ASAN FALSE)
+  set(COMPILER_RT_HAS_ASAN_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_ASAN
+  "Enable address sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_ASAN_DEFAULT})
+
 if (OS_NAME MATCHES "Linux|FreeBSD|Windows")
-  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME TRUE)
+  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME FALSE)
+  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME
+  "Enable address sanitizer static (Defaults based on system support)"
+  ${COMPILER_RT_ASAN_HAS_STATIC_RUNTIME_DEFAULT})
+
 # TODO: Add builtins support.
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND DFSAN_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Linux")
-  set(COMPILER_RT_HAS_DFSAN TRUE)
+  set(COMPILER_RT_HAS_DFSAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_DFSAN FALSE)
+  set(COMPILER_RT_HAS_DFSAN_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_DFSAN
+  "Enable data flow sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_DFSAN_DEFAULT})
+
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND LSAN_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Linux|FreeBSD")
-  set(COMPILER_RT_HAS_LSAN TRUE)
+  set(COMPILER_RT_HAS_LSAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_LSAN FALSE)
+  set(COMPILER_RT_HAS_LSAN_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_LSAN
+  "Enable leak sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_LSAN_DEFAULT})
+
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND MSAN_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Linux")
-  set(COMPILER_RT_HAS_MSAN TRUE)
+  set(COMPILER_RT_HAS_MSAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_MSAN FALSE)
+  set(COMPILER_RT_HAS_MSAN_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_MSAN
+  "Enable memory sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_MSAN_DEFAULT})
+
 if (PROFILE_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Darwin|Linux|FreeBSD")
-  set(COMPILER_RT_HAS_PROFILE TRUE)
+  set(COMPILER_RT_HAS_PROFILE_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_PROFILE FALSE)
+  set(COMPILER_RT_HAS_PROFILE_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_PROFILE
+  "Enable profile runtime (Defaults based on system support)"
+  ${COMPILER_RT_HAS_PROFILE_DEFAULT})
+
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND TSAN_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Linux|FreeBSD")
-  set(COMPILER_RT_HAS_TSAN TRUE)
+  set(COMPILER_RT_HAS_TSAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_TSAN FALSE)
+  set(COMPILER_RT_HAS_TSAN_DEFAULT FALSE)
 endif()
 
-if(APPLE)
-  option(COMPILER_RT_ENABLE_TSAN_OSX "Enable building TSan for OS X - Experimental" Off)
-  if(COMPILER_RT_ENABLE_TSAN_OSX)
-    set(COMPILER_RT_HAS_TSAN TRUE)
-  endif()
-endif()
+option(COMPILER_RT_HAS_TSAN
+  "Enable thread sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_TSAN_DEFAULT})
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND UBSAN_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Darwin|Linux|FreeBSD|Windows")
-  set(COMPILER_RT_HAS_UBSAN TRUE)
+  set(COMPILER_RT_HAS_UBSAN_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_UBSAN FALSE)
+  set(COMPILER_RT_HAS_UBSAN_DEFAULT FALSE)
 endif()
 
+option(COMPILER_RT_HAS_UBSAN
+  "Enable undefined behavior sanitizer (Defaults based on system support)"
+  ${COMPILER_RT_HAS_UBSAN_DEFAULT})
+
 # -msse3 flag is not valid for Mips therefore clang gives a warning
 # message with -msse3. But check_c_compiler_flags() checks only for
 # compiler error messages. Therefore COMPILER_RT_HAS_MSSE3_FLAG turns out to be
@@ -583,7 +616,12 @@
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND SAFESTACK_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Darwin|Linux|FreeBSD")
-  set(COMPILER_RT_HAS_SAFESTACK TRUE)
+  set(COMPILER_RT_HAS_SAFESTACK_DEFAULT TRUE)
 else()
-  set(COMPILER_RT_HAS_SAFESTACK FALSE)
+  set(COMPILER_RT_HAS_SAFESTACK_DEFAULT FALSE)
 endif()
+
+option(COMPILER_RT_HAS_SAFESTACK
+  "Enable safestack runtime (Defaults based on system support)"
+  ${COMPILER_RT_HAS_SAFESTACK_DEFAULT})
+