Index: test/sanitizer_common/CMakeLists.txt
===================================================================
--- test/sanitizer_common/CMakeLists.txt
+++ test/sanitizer_common/CMakeLists.txt
@@ -3,17 +3,41 @@
 set(SANITIZER_COMMON_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 set(SANITIZER_COMMON_TESTSUITES)
 
+# FIXME(dliew): We should switch to COMPILER_RT_SANITIZERS_TO_BUILD instead of
+# the hard coded `SUPPORTED_TOOLS_INIT` list once we know that the other
+# sanitizers work.
+set(SUPPORTED_TOOLS_INIT asan lsan msan tsan ubsan)
 set(SUPPORTED_TOOLS)
-if(CMAKE_SYSTEM_NAME MATCHES "Darwin|Linux|FreeBSD|NetBSD|SunOS")
-  list(APPEND SUPPORTED_TOOLS asan)
-endif()
-if(CMAKE_SYSTEM_NAME MATCHES "NetBSD" OR (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID))
-  list(APPEND SUPPORTED_TOOLS tsan)
-  list(APPEND SUPPORTED_TOOLS msan)
-  list(APPEND SUPPORTED_TOOLS ubsan)
-endif()
-if(CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID)
-  list(APPEND SUPPORTED_TOOLS lsan)
+  foreach(SANITIZER_TOOL ${SUPPORTED_TOOLS_INIT})
+    string(TOUPPER ${SANITIZER_TOOL} SANITIZER_TOOL_UPPER)
+    if (COMPILER_RT_HAS_${SANITIZER_TOOL_UPPER})
+      list(APPEND SUPPORTED_TOOLS ${SANITIZER_TOOL})
+    endif()
+  endforeach()
+
+# FIXME(dliew): Remove this.
+# Temporary helper for https://reviews.llvm.org/D55740
+message(
+  STATUS
+  "Generated Sanitizer SUPPORTED_TOOLS list on \"${CMAKE_SYSTEM_NAME}\" is"
+  " \"${SUPPORTED_TOOLS}\"")
+
+# FIXME(dliew): These tests should be made to work on all platforms.
+# Use the legacy list for now.
+if (ANDROID OR WINDOWS)
+  set(OLD_SUPPORTED_TOOLS ${SUPPORTED_TOOLS})
+  if (ANDROID)
+    set(SUPPORTED_TOOLS asan)
+  elseif (WINDOWS)
+    set(SUPPORTED_TOOLS "")
+  else()
+    message(FATAL_ERROR "Unhandled platform")
+  endif()
+	message(
+		AUTHOR_WARNING
+    "Replacing Sanitizer SUPPORTED_TOOLS list (${OLD_SUPPORTED_TOOLS}) with "
+    "\"${SUPPORTED_TOOLS}\"")
+  unset(OLD_SUPPORTED_TOOLS)
 endif()
 
 # FIXME(dliew): Remove this.
@@ -34,6 +58,8 @@
     darwin_filter_host_archs(${tool_toupper}_SUPPORTED_ARCH TEST_ARCH)
   endif()
 
+  # TODO(dliew): We should iterate over the different
+  # Apple platforms, not just macOS.
   foreach(arch ${TEST_ARCH})
     set(SANITIZER_COMMON_LIT_TEST_MODE ${tool})
     set(SANITIZER_COMMON_TEST_TARGET_ARCH ${arch})
@@ -42,8 +68,14 @@
     configure_lit_site_cfg(
       ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
       ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg)
-    list(APPEND SANITIZER_COMMON_TESTSUITES
-         ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
+    # FIXME(dliew): LSan i386 on Darwin is completly broken right now.
+    # so don't run the tests by default.
+    if (NOT (CMAKE_SYSTEM_NAME MATCHES "Darwin" AND
+             ${tool} STREQUAL "lsan" AND
+             ${arch} STREQUAL "i386"))
+      list(APPEND SANITIZER_COMMON_TESTSUITES
+           ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
+    endif()
   endforeach()
 endforeach()
 
Index: test/sanitizer_common/TestCases/Darwin/abort_on_error.cc
===================================================================
--- test/sanitizer_common/TestCases/Darwin/abort_on_error.cc
+++ test/sanitizer_common/TestCases/Darwin/abort_on_error.cc
@@ -1,7 +1,7 @@
 // Check that sanitizers on OS X crash the process by default (i.e.
 // abort_on_error=1). See also Linux/abort_on_error.cc.
 
-// RUN: %clangxx %s -o %t
+// RUN: %clangxx -DUSING_%tool_name %s -o %t
 
 // Intentionally don't inherit the default options.
 // RUN: env %tool_options='' not --crash %run %t 2>&1
@@ -9,11 +9,19 @@
 // When we use lit's default options, we shouldn't crash.
 // RUN: not %run %t 2>&1
 
+// Leak detection isn't treated as an error so `abort_on_error=1` doesn't work.
+// UNSUPPORTED: lsan
+
 int global;
 
 int main() {
+#if defined(USING_ubsan)
+  int value = 5;
+  int computation = value / 0; // Division by zero.
+#else
   volatile int *a = new int[100];
   delete[] a;
-  global = a[0];  // use-after-free: triggers ASan report.
+  global = a[0]; // use-after-free: triggers ASan/TSan report.
+#endif
   return 0;
 }
Index: test/sanitizer_common/TestCases/Darwin/print-stack-trace.cc
===================================================================
--- test/sanitizer_common/TestCases/Darwin/print-stack-trace.cc
+++ test/sanitizer_common/TestCases/Darwin/print-stack-trace.cc
@@ -1,6 +1,9 @@
 // RUN: %clangxx -O0 %s -o %t && %env_tool_opts=stack_trace_format=DEFAULT %run %t 2>&1 | FileCheck %s
 // RUN: %env_tool_opts=stack_trace_format='"frame:%n lineno:%l"' %run %t 2>&1 | FileCheck %s --check-prefix=CUSTOM
 
+// FIXME(dliew): Make this test work with other sanitizers
+// XFAIL: darwin && (lsan || tsan || ubsan)
+
 #include <sanitizer/common_interface_defs.h>
 
 static inline void FooBarBaz() {
Index: test/sanitizer_common/TestCases/Posix/dedup_token_length_test.cc
===================================================================
--- test/sanitizer_common/TestCases/Posix/dedup_token_length_test.cc
+++ test/sanitizer_common/TestCases/Posix/dedup_token_length_test.cc
@@ -10,6 +10,9 @@
 
 // XFAIL: netbsd && !asan
 
+// FIXME(dliew): Make this test work with other sanitizers
+// XFAIL: darwin && (lsan || tsan || ubsan)
+
 volatile int *null = 0;
 
 namespace Xyz {
Index: test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
===================================================================
--- test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
+++ test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
@@ -3,6 +3,8 @@
 // REQUIRES: stable-runtime
 
 // XFAIL: ubsan
+// FIXME(dliew): Make this test work on Darwin with LSan
+// XFAIL: darwin && lsan
 
 #include <sanitizer/common_interface_defs.h>
 #include <stdio.h>
Index: test/sanitizer_common/TestCases/symbolize_stack.cc
===================================================================
--- test/sanitizer_common/TestCases/symbolize_stack.cc
+++ test/sanitizer_common/TestCases/symbolize_stack.cc
@@ -2,6 +2,9 @@
 
 // Test that symbolizer does not crash on frame with large function name.
 
+// FIXME(dliew): Make this test work with the other sanitizers.
+// XFAIL: darwin && (lsan || tsan || ubsan)
+
 #include <sanitizer/common_interface_defs.h>
 #include <vector>