Index: compiler-rt/CMakeLists.txt
===================================================================
--- compiler-rt/CMakeLists.txt
+++ compiler-rt/CMakeLists.txt
@@ -230,6 +230,26 @@
 set_property(CACHE SANITIZER_GTEST_CXX PROPERTY STRINGS ;${CXXLIBS})
 handle_default_cxx_lib(SANITIZER_GTEST_CXX)
 
+set(SANITIZER_LIBCXX_CXX_ABI "default" CACHE STRING
+    "Specify C++ ABI library to use for libc++.")
+set(CXXABIS none default libcxxabi libcxxrt libstdc++ libsupc++)
+set_property(CACHE SANITIZER_LIBCXX_CXX_ABI PROPERTY STRINGS ;${CXXABIS})
+
+if (SANITIZER_LIBCXX_CXX_ABI STREQUAL "default")
+  if (APPLE OR CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+    # Forward "default" and let libc++ handle the rest.
+    set(SANITIZER_LIBCXX_CXX_ABI_VALUE "default")
+  elseif (FUCHSIA)
+    set(SANITIZER_LIBCXX_CXX_ABI_VALUE "libcxxabi")
+  elseif (SANITIZER_CXX_ABI STREQUAL "libcxxabi")
+    set(SANITIZER_LIBCXX_CXX_ABI_VALUE "libcxxabi")
+  else()
+    set(SANITIZER_LIBCXX_CXX_ABI_VALUE "libstdc++")
+  endif()
+else()
+  set(SANITIZER_LIBCXX_CXX_ABI_VALUE "${SANITIZER_LIBCXX_CXX_ABI}")
+endif()
+
 set(DEFAULT_SANITIZER_USE_STATIC_LLVM_UNWINDER OFF)
 if (FUCHSIA)
   set(DEFAULT_SANITIZER_USE_STATIC_LLVM_UNWINDER ON)
Index: compiler-rt/cmake/Modules/AddCompilerRT.cmake
===================================================================
--- compiler-rt/cmake/Modules/AddCompilerRT.cmake
+++ compiler-rt/cmake/Modules/AddCompilerRT.cmake
@@ -596,6 +596,7 @@
                -DLLVM_BINARY_DIR=${prefix}
                -DLLVM_LIBRARY_OUTPUT_INTDIR=${prefix}/lib
                -DLIBCXX_STANDALONE_BUILD=ON
+               -DLIBCXX_CXX_ABI=${SANITIZER_LIBCXX_CXX_ABI_VALUE}
                ${LIBCXX_CMAKE_ARGS}
     INSTALL_COMMAND ""
     STEP_TARGETS configure build
Index: compiler-rt/lib/fuzzer/CMakeLists.txt
===================================================================
--- compiler-rt/lib/fuzzer/CMakeLists.txt
+++ compiler-rt/lib/fuzzer/CMakeLists.txt
@@ -134,8 +134,7 @@
       CMAKE_ARGS -DCMAKE_CXX_COMPILER_WORKS=ON
                  -DLIBCXX_ENABLE_EXCEPTIONS=OFF
                  -DLIBCXX_ENABLE_SHARED=OFF
-                 -DLIBCXX_ABI_NAMESPACE=Fuzzer
-                 -DLIBCXX_CXX_ABI=none)
+                 -DLIBCXX_ABI_NAMESPACE=Fuzzer)
     target_compile_options(RTfuzzer.${arch} PRIVATE -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
     add_dependencies(RTfuzzer.${arch} libcxx_fuzzer_${arch}-build)
     target_compile_options(RTfuzzer_main.${arch} PRIVATE -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
Index: compiler-rt/lib/msan/tests/CMakeLists.txt
===================================================================
--- compiler-rt/lib/msan/tests/CMakeLists.txt
+++ compiler-rt/lib/msan/tests/CMakeLists.txt
@@ -50,8 +50,6 @@
   -fsanitize=memory
   # Don't need -stdlib=libc++ because we explicitly list libc++.so in the linker
   # inputs.
-  # FIXME: we build libcxx without cxxabi and need libstdc++ to provide it.
-  -lstdc++
 )
 
 append_list_if(COMPILER_RT_HAS_LIBDL -ldl MSAN_UNITTEST_LINK_FLAGS)
Index: libcxx/CMakeLists.txt
===================================================================
--- libcxx/CMakeLists.txt
+++ libcxx/CMakeLists.txt
@@ -140,17 +140,17 @@
 set(CXXABIS none default libcxxabi libcxxrt libstdc++ libsupc++ vcruntime)
 set_property(CACHE LIBCXX_CXX_ABI PROPERTY STRINGS ;${CXXABIS})
 
+find_path(
+  LIBCXX_LIBCXXABI_INCLUDES_INTERNAL
+  cxxabi.h
+  PATHS ${LLVM_MAIN_SRC_DIR}/projects/libcxxabi/include
+        ${LLVM_MAIN_SRC_DIR}/runtimes/libcxxabi/include
+        ${LLVM_MAIN_SRC_DIR}/../libcxxabi/include
+  NO_DEFAULT_PATH
+  NO_CMAKE_FIND_ROOT_PATH
+)
 # Setup the default options if LIBCXX_CXX_ABI is not specified.
 if (LIBCXX_CXX_ABI STREQUAL "default")
-  find_path(
-    LIBCXX_LIBCXXABI_INCLUDES_INTERNAL
-    cxxabi.h
-    PATHS ${LLVM_MAIN_SRC_DIR}/projects/libcxxabi/include
-          ${LLVM_MAIN_SRC_DIR}/runtimes/libcxxabi/include
-          ${LLVM_MAIN_SRC_DIR}/../libcxxabi/include
-    NO_DEFAULT_PATH
-    NO_CMAKE_FIND_ROOT_PATH
-  )
   if (LIBCXX_TARGETING_MSVC)
     # FIXME: Figure out how to configure the ABI library on Windows.
     set(LIBCXX_CXX_ABI_LIBNAME "vcruntime")
@@ -170,6 +170,10 @@
   endif()
 else()
   set(LIBCXX_CXX_ABI_LIBNAME "${LIBCXX_CXX_ABI}")
+  if (LIBCXX_CXX_ABI STREQUAL "libcxxabi" AND
+      IS_DIRECTORY "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}")
+    set(LIBCXX_CXX_ABI_INCLUDE_PATHS "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}")
+  endif()
 endif()
 
 # Use a static copy of the ABI library when linking libc++. This option