diff --git a/compiler-rt/cmake/Modules/HandleCompilerRT.cmake b/compiler-rt/cmake/Modules/HandleCompilerRT.cmake
--- a/compiler-rt/cmake/Modules/HandleCompilerRT.cmake
+++ b/compiler-rt/cmake/Modules/HandleCompilerRT.cmake
@@ -6,11 +6,11 @@
 function(cache_compiler_rt_library err_flag name target library_file)
   if(err_flag OR NOT EXISTS "${library_file}")
     message(STATUS "Failed to find compiler-rt ${name} library for ${target}")
-    set(COMPILER_RT_LIBRARY-${name}-${target} "NOTFOUND" CACHE INTERNAL
+    set(COMPILER_RT_LIBRARY_${name}_${target} "NOTFOUND" CACHE INTERNAL
         "compiler-rt ${name} library for ${target}")
   else()
     message(STATUS "Found compiler-rt ${name} library: ${library_file}")
-    set(COMPILER_RT_LIBRARY-${name}-${target} "${library_file}" CACHE INTERNAL
+    set(COMPILER_RT_LIBRARY_${name}_${target} "${library_file}" CACHE INTERNAL
         "compiler-rt ${name} library for ${target}")
   endif()
 endfunction()
@@ -20,6 +20,8 @@
 # This calls cache_compiler_rt_library that caches the path to speed up
 # repeated invocations with the same `name` and `target`.
 function(find_compiler_rt_library name target variable)
+  # While we can use compiler-rt runtimes with other compilers, we need to
+  # query the compiler for runtime location and thus we require Clang.
   if(NOT CMAKE_CXX_COMPILER_ID MATCHES Clang)
     set(${variable} "NOTFOUND" PARENT_SCOPE)
     return()
@@ -27,7 +29,7 @@
   if (NOT target AND CMAKE_CXX_COMPILER_TARGET)
     set(target "${CMAKE_CXX_COMPILER_TARGET}")
   endif()
-  if(NOT DEFINED COMPILER_RT_LIBRARY-builtins-${target})
+  if(NOT DEFINED COMPILER_RT_LIBRARY_builtins_${target})
     # If the cache variable is not defined, invoke clang and then 
     # set it with cache_compiler_rt_library.
     set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${SANITIZER_COMMON_FLAGS}
@@ -45,21 +47,20 @@
     )
     string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
     file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-    cache_compiler_rt_library(${HAD_ERROR}
-      builtins "${target}" "${LIBRARY_FILE}")
+    cache_compiler_rt_library(${HAD_ERROR} builtins "${target}" "${LIBRARY_FILE}")
   endif()
-  if(NOT COMPILER_RT_LIBRARY-builtins-${target})
+  if(NOT COMPILER_RT_LIBRARY_builtins_${target})
     set(${variable} "NOTFOUND" PARENT_SCOPE)
     return()
   endif()
-  if(NOT DEFINED COMPILER_RT_LIBRARY-${name}-${target})
-    # clang gives only the builtins library path. Other library paths are
+  if(NOT DEFINED COMPILER_RT_LIBRARY_${name}_${target})
+    # Clang gives only the builtins library path. Other library paths are
     # obtained by substituting "builtins" with ${name} in the builtins
     # path and then checking if the resultant path exists. The result of
     # this check is also cached by cache_compiler_rt_library.
-    set(LIBRARY_FILE "${COMPILER_RT_LIBRARY-builtins-${target}}")
+    set(LIBRARY_FILE "${COMPILER_RT_LIBRARY_builtins_${target}}")
     string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
     cache_compiler_rt_library(FALSE "${name}" "${target}" "${LIBRARY_FILE}")
   endif()
-  set(${variable} "${COMPILER_RT_LIBRARY-${name}-${target}}" PARENT_SCOPE)
+  set(${variable} "${COMPILER_RT_LIBRARY_${name}_${target}}" PARENT_SCOPE)
 endfunction()
diff --git a/libcxx/cmake/Modules/HandleCompilerRT.cmake b/libcxx/cmake/Modules/HandleCompilerRT.cmake
--- a/libcxx/cmake/Modules/HandleCompilerRT.cmake
+++ b/libcxx/cmake/Modules/HandleCompilerRT.cmake
@@ -1,30 +1,69 @@
-function(find_compiler_rt_library name dest)
+# Check if compile-rt library file path exists.
+# If found, cache the path in:
+#    COMPILER_RT_LIBRARY_<name>_<target>
+# If err_flag is true OR path not found, emit a message and set:
+#    COMPILER_RT_LIBRARY_<name>_<target> to NOTFOUND
+function(cache_compiler_rt_library err_flag name target library_file)
+  if(err_flag OR NOT EXISTS "${library_file}")
+    message(STATUS "Failed to find compiler-rt ${name} library")
+    set(COMPILER_RT_LIBRARY_${name} "NOTFOUND" CACHE INTERNAL
+        "compiler-rt ${name} library")
+  else()
+    message(STATUS "Found compiler-rt ${name} library: ${library_file}")
+    set(COMPILER_RT_LIBRARY_${name} "${library_file}" CACHE INTERNAL
+        "compiler-rt ${name} library")
+  endif()
+endfunction()
+
+# Find the path to compiler-rt library `name` (e.g. "builtins") for
+# the specified `target` (e.g. "x86_64-linux") and return it in `variable`.
+# This calls cache_compiler_rt_library that caches the path to speed up
+# repeated invocations with the same `name` and `target`.
+function(find_compiler_rt_library name variable)
+  # While we can use compiler-rt runtimes with other compilers, we need to
+  # query the compiler for runtime location and thus we require Clang.
+  if(NOT CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
   if (NOT DEFINED LIBCXX_COMPILE_FLAGS)
     message(FATAL_ERROR "LIBCXX_COMPILE_FLAGS must be defined when using this function")
   endif()
-  set(dest "" PARENT_SCOPE)
-  set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBCXX_COMPILE_FLAGS}
-      "--rtlib=compiler-rt" "--print-libgcc-file-name")
-  if (CMAKE_CXX_COMPILER_ID MATCHES Clang AND CMAKE_CXX_COMPILER_TARGET)
-    list(APPEND CLANG_COMMAND "--target=${CMAKE_CXX_COMPILER_TARGET}")
+  if (NOT target AND CMAKE_CXX_COMPILER_TARGET)
+    set(target "${CMAKE_CXX_COMPILER_TARGET}")
   endif()
-  get_property(LIBCXX_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
-  string(REPLACE " " ";" LIBCXX_CXX_FLAGS "${LIBCXX_CXX_FLAGS}")
-  list(APPEND CLANG_COMMAND ${LIBCXX_CXX_FLAGS})
-  execute_process(
-      COMMAND ${CLANG_COMMAND}
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE LIBRARY_FILE
-  )
-  string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
-  file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-  string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
-  if (NOT HAD_ERROR AND EXISTS "${LIBRARY_FILE}")
-    message(STATUS "Found compiler-rt library: ${LIBRARY_FILE}")
-    set(${dest} "${LIBRARY_FILE}" PARENT_SCOPE)
-  else()
-    message(STATUS "Failed to find compiler-rt library")
+  if(NOT DEFINED COMPILER_RT_LIBRARY_builtins)
+    set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBCXX_COMPILE_FLAGS}
+        "--rtlib=compiler-rt" "--print-libgcc-file-name")
+    if (target)
+      list(APPEND CLANG_COMMAND "--target=${target}")
+    endif()
+    get_property(LIBCXX_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
+    string(REPLACE " " ";" LIBCXX_CXX_FLAGS "${LIBCXX_CXX_FLAGS}")
+    list(APPEND CLANG_COMMAND ${LIBCXX_CXX_FLAGS})
+    execute_process(
+        COMMAND ${CLANG_COMMAND}
+        RESULT_VARIABLE HAD_ERROR
+        OUTPUT_VARIABLE LIBRARY_FILE
+    )
+    string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
+    file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
+    cache_compiler_rt_library(${HAD_ERROR} builtins "${target}" "${LIBRARY_FILE}")
+  endif()
+  if(NOT COMPILER_RT_LIBRARY_builtins)
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
+  if(NOT DEFINED COMPILER_RT_LIBRARY_${name})
+    # Clang gives only the builtins library path. Other library paths are
+    # obtained by substituting "builtins" with ${name} in the builtins
+    # path and then checking if the resultant path exists. The result of
+    # this check is also cached by cache_compiler_rt_library.
+    set(LIBRARY_FILE "${COMPILER_RT_LIBRARY_builtins}")
+    string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
+    cache_compiler_rt_library(FALSE "${name}" "${target}" "${LIBRARY_FILE}")
   endif()
+  set(${variable} "${COMPILER_RT_LIBRARY_${name}}" PARENT_SCOPE)
 endfunction()
 
 function(find_compiler_rt_dir dest)
diff --git a/libcxxabi/cmake/Modules/HandleCompilerRT.cmake b/libcxxabi/cmake/Modules/HandleCompilerRT.cmake
--- a/libcxxabi/cmake/Modules/HandleCompilerRT.cmake
+++ b/libcxxabi/cmake/Modules/HandleCompilerRT.cmake
@@ -1,30 +1,69 @@
-function(find_compiler_rt_library name dest)
+# Check if compile-rt library file path exists.
+# If found, cache the path in:
+#    COMPILER_RT_LIBRARY_<name>_<target>
+# If err_flag is true OR path not found, emit a message and set:
+#    COMPILER_RT_LIBRARY_<name>_<target> to NOTFOUND
+function(cache_compiler_rt_library err_flag name target library_file)
+  if(err_flag OR NOT EXISTS "${library_file}")
+    message(STATUS "Failed to find compiler-rt ${name} library for ${target}")
+    set(COMPILER_RT_LIBRARY_${name}_${target} "NOTFOUND" CACHE INTERNAL
+        "compiler-rt ${name} library for ${target}")
+  else()
+    message(STATUS "Found compiler-rt ${name} library for ${target}: ${library_file}")
+    set(COMPILER_RT_LIBRARY_${name}_${target} "${library_file}" CACHE INTERNAL
+        "compiler-rt ${name} library for ${target}")
+  endif()
+endfunction()
+
+# Find the path to compiler-rt library `name` (e.g. "builtins") for
+# the specified `target` (e.g. "x86_64-linux") and return it in `variable`.
+# This calls cache_compiler_rt_library that caches the path to speed up
+# repeated invocations with the same `name` and `target`.
+function(find_compiler_rt_library name variable)
+  # While we can use compiler-rt runtimes with other compilers, we need to
+  # query the compiler for runtime location and thus we require Clang.
+  if(NOT CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
   if (NOT DEFINED LIBCXXABI_COMPILE_FLAGS)
     message(FATAL_ERROR "LIBCXXABI_COMPILE_FLAGS must be defined when using this function")
   endif()
-  set(dest "" PARENT_SCOPE)
-  set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBCXXABI_COMPILE_FLAGS}
-      "--rtlib=compiler-rt" "--print-libgcc-file-name")
-  if (CMAKE_CXX_COMPILER_ID MATCHES Clang AND CMAKE_CXX_COMPILER_TARGET)
-    list(APPEND CLANG_COMMAND "--target=${CMAKE_CXX_COMPILER_TARGET}")
+  if (NOT target AND CMAKE_CXX_COMPILER_TARGET)
+    set(target "${CMAKE_CXX_COMPILER_TARGET}")
   endif()
-  get_property(LIBCXXABI_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
-  string(REPLACE " " ";" LIBCXXABI_CXX_FLAGS "${LIBCXXABI_CXX_FLAGS}")
-  list(APPEND CLANG_COMMAND ${LIBCXXABI_CXX_FLAGS})
-  execute_process(
-      COMMAND ${CLANG_COMMAND}
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE LIBRARY_FILE
-  )
-  string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
-  file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-  string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
-  if (NOT HAD_ERROR AND EXISTS "${LIBRARY_FILE}")
-    message(STATUS "Found compiler-rt library: ${LIBRARY_FILE}")
-    set(${dest} "${LIBRARY_FILE}" PARENT_SCOPE)
-  else()
-    message(STATUS "Failed to find compiler-rt library")
+  if(NOT DEFINED COMPILER_RT_LIBRARY_builtins_${target})
+    set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBCXXABI_COMPILE_FLAGS}
+        "--rtlib=compiler-rt" "--print-libgcc-file-name")
+    if (target)
+      list(APPEND CLANG_COMMAND "--target=${target}")
+    endif()
+    get_property(LIBCXXABI_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
+    string(REPLACE " " ";" LIBCXX_CXX_FLAGS "${LIBCXXABI_CXX_FLAGS}")
+    list(APPEND CLANG_COMMAND ${LIBCXXABI_CXX_FLAGS})
+    execute_process(
+        COMMAND ${CLANG_COMMAND}
+        RESULT_VARIABLE HAD_ERROR
+        OUTPUT_VARIABLE LIBRARY_FILE
+    )
+    string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
+    file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
+    cache_compiler_rt_library(${HAD_ERROR} builtins "${target}" "${LIBRARY_FILE}")
+  endif()
+  if(NOT COMPILER_RT_LIBRARY_builtins_${target})
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
+  if(NOT DEFINED COMPILER_RT_LIBRARY_${name}_${target})
+    # Clang gives only the builtins library path. Other library paths are
+    # obtained by substituting "builtins" with ${name} in the builtins
+    # path and then checking if the resultant path exists. The result of
+    # this check is also cached by cache_compiler_rt_library.
+    set(LIBRARY_FILE "${COMPILER_RT_LIBRARY_builtins}_${target}")
+    string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
+    cache_compiler_rt_library(FALSE "${name}" "${target}" "${LIBRARY_FILE}")
   endif()
+  set(${variable} "${COMPILER_RT_LIBRARY_${name}_${target}}" PARENT_SCOPE)
 endfunction()
 
 function(find_compiler_rt_dir dest)
diff --git a/libunwind/cmake/Modules/HandleCompilerRT.cmake b/libunwind/cmake/Modules/HandleCompilerRT.cmake
--- a/libunwind/cmake/Modules/HandleCompilerRT.cmake
+++ b/libunwind/cmake/Modules/HandleCompilerRT.cmake
@@ -1,30 +1,69 @@
-function(find_compiler_rt_library name dest)
+# Check if compile-rt library file path exists.
+# If found, cache the path in:
+#    COMPILER_RT_LIBRARY_<name>_<target>
+# If err_flag is true OR path not found, emit a message and set:
+#    COMPILER_RT_LIBRARY_<name>_<target> to NOTFOUND
+function(cache_compiler_rt_library err_flag name target library_file)
+  if(err_flag OR NOT EXISTS "${library_file}")
+    message(STATUS "Failed to find compiler-rt ${name} library")
+    set(COMPILER_RT_LIBRARY_${name} "NOTFOUND" CACHE INTERNAL
+        "compiler-rt ${name} library")
+  else()
+    message(STATUS "Found compiler-rt ${name} library: ${library_file}")
+    set(COMPILER_RT_LIBRARY_${name} "${library_file}" CACHE INTERNAL
+        "compiler-rt ${name} library")
+  endif()
+endfunction()
+
+# Find the path to compiler-rt library `name` (e.g. "builtins") for
+# the specified `target` (e.g. "x86_64-linux") and return it in `variable`.
+# This calls cache_compiler_rt_library that caches the path to speed up
+# repeated invocations with the same `name` and `target`.
+function(find_compiler_rt_library name variable)
+  # While we can use compiler-rt runtimes with other compilers, we need to
+  # query the compiler for runtime location and thus we require Clang.
+  if(NOT CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
   if (NOT DEFINED LIBUNWIND_COMPILE_FLAGS)
     message(FATAL_ERROR "LIBUNWIND_COMPILE_FLAGS must be defined when using this function")
   endif()
-  set(dest "" PARENT_SCOPE)
-  set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBUNWIND_COMPILE_FLAGS}
-      "--rtlib=compiler-rt" "--print-libgcc-file-name")
-  if (CMAKE_CXX_COMPILER_ID MATCHES Clang AND CMAKE_CXX_COMPILER_TARGET)
-    list(APPEND CLANG_COMMAND "--target=${CMAKE_CXX_COMPILER_TARGET}")
+  if (NOT target AND CMAKE_CXX_COMPILER_TARGET)
+    set(target "${CMAKE_CXX_COMPILER_TARGET}")
   endif()
-  get_property(LIBUNWIND_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
-  string(REPLACE " " ";" LIBUNWIND_CXX_FLAGS "${LIBUNWIND_CXX_FLAGS}")
-  list(APPEND CLANG_COMMAND ${LIBUNWIND_CXX_FLAGS})
-  execute_process(
-      COMMAND ${CLANG_COMMAND}
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE LIBRARY_FILE
-  )
-  string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
-  file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-  string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
-  if (NOT HAD_ERROR AND EXISTS "${LIBRARY_FILE}")
-    message(STATUS "Found compiler-rt library: ${LIBRARY_FILE}")
-    set(${dest} "${LIBRARY_FILE}" PARENT_SCOPE)
-  else()
-    message(STATUS "Failed to find compiler-rt library")
+  if(NOT DEFINED COMPILER_RT_LIBRARY_builtins)
+    set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBUNWIND_COMPILE_FLAGS}
+        "--rtlib=compiler-rt" "--print-libgcc-file-name")
+    if (target)
+      list(APPEND CLANG_COMMAND "--target=${target}")
+    endif()
+    get_property(LIBUNWIND_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
+    string(REPLACE " " ";" LIBUNWIND_CXX_FLAGS "${LIBUNWIND_CXX_FLAGS}")
+    list(APPEND CLANG_COMMAND ${LIBUNWIND_CXX_FLAGS})
+    execute_process(
+        COMMAND ${CLANG_COMMAND}
+        RESULT_VARIABLE HAD_ERROR
+        OUTPUT_VARIABLE LIBRARY_FILE
+    )
+    string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
+    file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
+    cache_compiler_rt_library(${HAD_ERROR} builtins "${target}" "${LIBRARY_FILE}")
+  endif()
+  if(NOT COMPILER_RT_LIBRARY_builtins)
+    set(${variable} "NOTFOUND" PARENT_SCOPE)
+    return()
+  endif()
+  if(NOT DEFINED COMPILER_RT_LIBRARY_${name})
+    # Clang gives only the builtins library path. Other library paths are
+    # obtained by substituting "builtins" with ${name} in the builtins
+    # path and then checking if the resultant path exists. The result of
+    # this check is also cached by cache_compiler_rt_library.
+    set(LIBRARY_FILE "${COMPILER_RT_LIBRARY_builtins}")
+    string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
+    cache_compiler_rt_library(FALSE "${name}" "${target}" "${LIBRARY_FILE}")
   endif()
+  set(${variable} "${COMPILER_RT_LIBRARY_${name}}" PARENT_SCOPE)
 endfunction()
 
 function(find_compiler_rt_dir dest)