diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -251,7 +251,7 @@
 
 # Target options --------------------------------------------------------------
 option(LIBCXX_BUILD_32_BITS "Build 32 bit libc++." ${LLVM_BUILD_32_BITS})
-set(LIBCXX_TARGET_TRIPLE "" CACHE STRING "Use alternate target triple.")
+set(LIBCXX_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Use alternate target triple.")
 set(LIBCXX_SYSROOT "" CACHE STRING "Use alternate sysroot.")
 set(LIBCXX_GCC_TOOLCHAIN "" CACHE STRING "Use alternate GCC toolchain.")
 
@@ -480,10 +480,6 @@
   set(LIBCXX_GCC_TOOLCHAIN "${CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN}")
 endif()
 
-if(LIBCXX_TARGET_TRIPLE)
-  set(TARGET_TRIPLE "${LIBCXX_TARGET_TRIPLE}")
-endif()
-
 # Configure compiler.
 include(config-ix)
 
diff --git a/libcxx/lib/abi/CMakeLists.txt b/libcxx/lib/abi/CMakeLists.txt
--- a/libcxx/lib/abi/CMakeLists.txt
+++ b/libcxx/lib/abi/CMakeLists.txt
@@ -41,7 +41,7 @@
 endfunction()
 
 cxx_abi_list_identifier(abi_list_identifier
-  "${TARGET_TRIPLE}"
+  "${LIBCXX_TARGET_TRIPLE}"
   "${LIBCXX_CXX_ABI_LIBNAME}"
   "${LIBCXX_ABI_VERSION}"
   "${LIBCXX_ABI_UNSTABLE}"
diff --git a/libcxx/test/CMakeLists.txt b/libcxx/test/CMakeLists.txt
--- a/libcxx/test/CMakeLists.txt
+++ b/libcxx/test/CMakeLists.txt
@@ -105,8 +105,8 @@
   serialize_lit_param(enable_debug_tests False)
 endif()
 
-if (TARGET_TRIPLE)
-  serialize_lit_param(target_triple "\"${TARGET_TRIPLE}\"")
+if (LIBCXX_TARGET_TRIPLE)
+  serialize_lit_param(target_triple "\"${LIBCXX_TARGET_TRIPLE}\"")
 endif()
 
 if (LLVM_USE_SANITIZER)
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -111,7 +111,7 @@
 set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
     "Define suffix of library directory name (32/64)")
 option(LIBCXXABI_INSTALL_LIBRARY "Install the libc++abi library." ON)
-set(LIBCXXABI_TARGET_TRIPLE "" CACHE STRING "Target triple for cross compiling.")
+set(LIBCXXABI_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Target triple for cross compiling.")
 set(LIBCXXABI_GCC_TOOLCHAIN "" CACHE PATH "GCC toolchain for cross compiling.")
 set(LIBCXXABI_SYSROOT "" CACHE PATH "Sysroot for cross compiling.")
 set(LIBCXXABI_LIBCXX_LIBRARY_PATH "" CACHE PATH "The path to libc++ library.")
@@ -273,10 +273,6 @@
   set(LIBCXXABI_SYSROOT "${CMAKE_SYSROOT}")
 endif()
 
-if (LIBCXXABI_TARGET_TRIPLE)
-  set(TARGET_TRIPLE "${LIBCXXABI_TARGET_TRIPLE}")
-endif()
-
 # Configure compiler. Must happen after setting the target flags.
 include(config-ix)
 
diff --git a/libcxxabi/test/CMakeLists.txt b/libcxxabi/test/CMakeLists.txt
--- a/libcxxabi/test/CMakeLists.txt
+++ b/libcxxabi/test/CMakeLists.txt
@@ -86,8 +86,8 @@
   serialize_lit_param(use_sanitizer "\"${LLVM_USE_SANITIZER}\"")
 endif()
 
-if (TARGET_TRIPLE)
-  serialize_lit_param(target_triple "\"${TARGET_TRIPLE}\"")
+if (LIBCXXABI_TARGET_TRIPLE)
+  serialize_lit_param(target_triple "\"${LIBCXXABI_TARGET_TRIPLE}\"")
 endif()
 
 if (LIBCXXABI_BUILD_32_BITS)
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -77,7 +77,7 @@
 cmake_dependent_option(LIBUNWIND_INSTALL_SHARED_LIBRARY
   "Install the shared libunwind library." ON
   "LIBUNWIND_ENABLE_SHARED;LIBUNWIND_INSTALL_LIBRARY" OFF)
-set(LIBUNWIND_TARGET_TRIPLE "" CACHE STRING "Target triple for cross compiling.")
+set(LIBUNWIND_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Target triple for cross compiling.")
 set(LIBUNWIND_GCC_TOOLCHAIN "" CACHE PATH "GCC toolchain for cross compiling.")
 set(LIBUNWIND_SYSROOT "" CACHE PATH "Sysroot for cross compiling.")
 set(LIBUNWIND_TEST_LINKER_FLAGS "" CACHE STRING
@@ -167,10 +167,6 @@
   set(LIBUNWIND_SYSROOT "${CMAKE_SYSROOT}")
 endif()
 
-if (LIBUNWIND_TARGET_TRIPLE)
-  set(TARGET_TRIPLE "${LIBUNWIND_TARGET_TRIPLE}")
-endif()
-
 # Configure compiler.
 include(config-ix)
 
diff --git a/libunwind/test/CMakeLists.txt b/libunwind/test/CMakeLists.txt
--- a/libunwind/test/CMakeLists.txt
+++ b/libunwind/test/CMakeLists.txt
@@ -36,8 +36,8 @@
   serialize_lit_param(use_sanitizer "\"${LLVM_USE_SANITIZER}\"")
 endif()
 
-if (TARGET_TRIPLE)
-  serialize_lit_param(target_triple "\"${TARGET_TRIPLE}\"")
+if (LIBUNWIND_TARGET_TRIPLE)
+  serialize_lit_param(target_triple "\"${LIBUNWIND_TARGET_TRIPLE}\"")
 endif()
 
 if (LIBUNWIND_BUILD_32_BITS)