diff --git a/llvm/cmake/modules/LLVMExternalProjectUtils.cmake b/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
index d457389..c851eb8 100644
--- a/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
+++ b/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
@@ -195,8 +195,16 @@
 
   # Add top-level targets
   foreach(target ${ARG_EXTRA_TARGETS})
+    string(REPLACE ":" ";" target_list ${target})
+    list(GET target_list 0 target)
+    list(LENGTH target_list target_list_len)
+    if(${target_list_len} GREATER 1)
+      list(GET target_list 1 target_name)
+    else()
+      set(target_name "${target}")
+    endif()
     llvm_ExternalProject_BuildCmd(build_runtime_cmd ${target} ${BINARY_DIR})
-    add_custom_target(${target}
+    add_custom_target(${target_name}
       COMMAND ${build_runtime_cmd}
       DEPENDS ${name}-configure
       WORKING_DIRECTORY ${BINARY_DIR}
diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
index ded3a71..3e3eff3 100644
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -62,7 +62,7 @@
   set(LLVM_MAIN_SRC_DIR ${LLVM_BUILD_MAIN_SRC_DIR})
 
   if(APPLE)
-   set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
+    set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
   endif()
 
   set(SAFE_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
@@ -96,15 +96,33 @@
     # The subdirectories need to treat this as standalone builds
     set(${canon_name}_STANDALONE_BUILD On)
 
+    if(LLVM_RUNTIMES_TARGET)
+      if(NOT "${entry}" MATCHES "compiler-rt")
+        set(${canon_name}_INSTALL_PREFIX "lib/${LLVM_RUNTIMES_TARGET}/" CACHE STRING "" FORCE)
+      endif()
+    endif()
+
     # Setting a variable to let sub-projects detect which other projects
     # will be included under here.
     set(HAVE_${canon_name} On)
   endforeach()
 
+  set(SAFE_LLVM_BINARY_DIR ${LLVM_BINARY_DIR})
+  set(SAFE_LLVM_LIBRARY_OUTPUT_INTDIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
+  set(SAFE_LLVM_RUNTIMES_OUTPUT_INTDIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
+
   # We do this in two loops so that HAVE_* is set for each runtime before the
   # other runtimes are added.
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
+
+    if(LLVM_RUNTIMES_TARGET)
+      if(NOT "${entry}" MATCHES "compiler-rt")
+        set(LLVM_BINARY_DIR "${LLVM_LIBRARY_DIR}/${LLVM_RUNTIMES_TARGET}")
+        set(LLVM_LIBRARY_OUTPUT_INTDIR "${LLVM_LIBRARY_DIR}/${LLVM_RUNTIMES_TARGET}/lib")
+        set(LLVM_RUNTIME_OUTPUT_INTDIR "${LLVM_TOOLS_BINARY_DIR}/${LLVM_RUNTIMES_TARGET}")
+      endif()
+    endif()
     
     # Between each sub-project we want to cache and clear the LIT properties
     set_property(GLOBAL PROPERTY LLVM_LIT_TESTSUITES)
@@ -123,6 +141,14 @@
     list(APPEND RUNTIMES_LIT_PARAMS ${LLVM_LIT_PARAMS})
     list(APPEND RUNTIMES_LIT_DEPENDS ${LLVM_LIT_DEPENDS})
     list(APPEND RUNTIMES_LIT_EXTRA_ARGS ${LLVM_LIT_EXTRA_ARGS})
+
+    if(LLVM_RUNTIMES_TARGET)
+      if(NOT "${entry}" MATCHES "compiler-rt")
+        set(LLVM_BINARY_DIR "${SAFE_LLVM_BINARY_DIR}")
+        set(LLVM_LIBRARY_OUTPUT_INTDIR "${SAFE_LLVM_LIBRARY_OUTPUT_INTDIR}")
+        set(LLVM_RUNTIME_OUTPUT_INTDIR "${SAFE_LLVM_RUNTIME_OUTPUT_INTDIR}")
+      endif()
+    endif()
   endforeach()
 
   if(LLVM_INCLUDE_TESTS)
@@ -147,9 +173,9 @@
         message(SEND_ERROR "Missing target for runtime component ${component}!")
         continue()
       endif()
-      if(LLVM_INCLUDE_TESTS AND NOT TARGET check-${component})
-        message(SEND_ERROR "Missing check target for runtime component ${component}!")
-        continue()
+
+      if(TARGET check-${component})
+        list(APPEND SUB_CHECK_TARGETS check-${component})
       endif()
 
       if(TARGET install-${component})
@@ -157,14 +183,18 @@
       endif()
     endforeach()
 
-    configure_file(
-      ${CMAKE_CURRENT_SOURCE_DIR}/Components.cmake.in
-      ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
+    if(LLVM_RUNTIMES_TARGET)
+      configure_file(
+        ${CMAKE_CURRENT_SOURCE_DIR}/Components.cmake.in
+        ${LLVM_BINARY_DIR}/runtimes/${LLVM_RUNTIMES_TARGET}/Components.cmake)
+    else()
+      configure_file(
+        ${CMAKE_CURRENT_SOURCE_DIR}/Components.cmake.in
+        ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
+    endif()
   endif()
 
 else() # if this is included from LLVM's CMake
-  include(${LLVM_BINARY_DIR}/runtimes/Components.cmake OPTIONAL)
-  set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
   include(LLVMExternalProjectUtils)
 
   if(NOT LLVM_BUILD_RUNTIMES)
@@ -190,6 +220,10 @@
       add_custom_target(builtins)
       add_custom_target(install-builtins)
       foreach(target ${LLVM_BUILTIN_TARGETS})
+        if(target STREQUAL "default")
+          set(target ${LLVM_DEFAULT_TARGET_TRIPLE})
+        endif()
+
         string(REPLACE "-" ";" builtin_target_list ${target})
         foreach(item ${builtin_target_list})
           string(TOLOWER "${item}" item_lower)
@@ -246,42 +280,137 @@
     list(APPEND runtime_names ${projName})
   endforeach()
 
-  if(runtimes)
+  # runtime_register_target(target)
+  #   Utility function to register external runtime target.
+  function(runtime_register_target target)
+    if(target STREQUAL LLVM_DEFAULT_TARGET_TRIPLE)
+      include(${LLVM_BINARY_DIR}/runtimes/Components.cmake OPTIONAL)
+      set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
+    else()
+      include(${LLVM_BINARY_DIR}/runtimes/${target}/Components.cmake OPTIONAL)
+      set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/${target}/Components.cmake)
+    endif()
 
     foreach(runtime_name ${runtime_names})
-      list(APPEND extra_targets
-        ${runtime_name}
-        install-${runtime_name})
+      list(APPEND ${target}_extra_targets
+        ${runtime_name}-${target}
+        install-${runtime_name}-${target})
       if(LLVM_INCLUDE_TESTS)
-        list(APPEND test_targets check-${runtime_name})
+        list(APPEND ${target}_test_targets check-${runtime_name}-${target})
       endif()
     endforeach()
 
+    foreach(name IN LISTS SUB_COMPONENTS SUB_INSTALL_TARGETS)
+      list(APPEND ${target}_extra_targets "${name}:${name}-${target}")
+    endforeach()
+
     if(LLVM_INCLUDE_TESTS)
-      list(APPEND test_targets runtimes-test-depends check-runtimes)
-      foreach(component ${SUB_COMPONENTS})
-        list(APPEND SUB_COMPONENT_CHECK_TARGETS check-${component})
+      list(APPEND ${target}_test_targets runtimes-test-depends-${target} check-runtimes-${target})
+      foreach(name IN LISTS SUB_CHECK_TARGETS)
+        list(APPEND ${target}_test_targets "${name}:${name}-${target}")
+        list(APPEND test_targets ${name}-${target})
       endforeach()
+      set(test_targets "${test_targets}" PARENT_SCOPE)
     endif()
 
-    # Create a runtimes target that uses this file as its top-level CMake file.
-    # The runtimes target is a configuration of all the runtime libraries
-    # together in a single CMake invocaiton.
-    llvm_ExternalProject_Add(runtimes
+    get_cmake_property(variableNames VARIABLES)
+    foreach(variableName ${variableNames})
+      if(variableName MATCHES "^RUNTIMES_${target}")
+        string(REPLACE "RUNTIMES_${target}_" "" new_name ${variableName})
+        list(APPEND ${target}_extra_args "-D${new_name}=${${variableName}}")
+      endif()
+    endforeach()
+
+    if(NOT target STREQUAL LLVM_DEFAULT_TARGET_TRIPLE)
+      list(APPEND ${target}_extra_args "-DLLVM_RUNTIMES_TARGET=${target}")
+    endif()
+
+    llvm_ExternalProject_Add(runtimes-${target}
                              ${CMAKE_CURRENT_SOURCE_DIR}
                              DEPENDS ${deps}
                              # Builtins were built separately above
                              CMAKE_ARGS -DCOMPILER_RT_BUILD_BUILTINS=Off
                                         -DLLVM_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
+                                        -DCMAKE_C_COMPILER_TARGET=${target}
+                                        -DCMAKE_CXX_COMPILER_TARGET=${target}
+                                        -DCMAKE_ASM_COMPILER_TARGET=${target}
+                                        -DCMAKE_C_COMPILER_WORKS=ON
+                                        -DCMAKE_CXX_COMPILER_WORKS=ON
+                                        -DCMAKE_ASM_COMPILER_WORKS=ON
+                                        -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+                                        ${${target}_extra_args}
                              PASSTHROUGH_PREFIXES ${prefixes}
-                             EXTRA_TARGETS ${extra_targets}
-                                            ${test_targets}
-                                            ${SUB_COMPONENTS}
-                                            ${SUB_COMPONENT_CHECK_TARGETS}
-                                            ${SUB_INSTALL_TARGETS}
+                             EXTRA_TARGETS ${${target}_extra_targets}
+                                           ${${target}_test_targets}
                              USE_TOOLCHAIN
                              ${EXTRA_ARGS})
-    
+  endfunction()
+
+  if(runtimes)
+    # Create a runtimes target that uses this file as its top-level CMake file.
+    # The runtimes target is a configuration of all the runtime libraries
+    # together in a single CMake invocaiton.
+    if(NOT LLVM_RUNTIME_TARGETS)
+      include(${LLVM_BINARY_DIR}/runtimes/Components.cmake OPTIONAL)
+      set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
+
+      foreach(runtime_name ${runtime_names})
+        list(APPEND extra_targets
+          ${runtime_name}
+          install-${runtime_name})
+        if(LLVM_INCLUDE_TESTS)
+          list(APPEND test_targets check-${runtime_name})
+        endif()
+      endforeach()
+
+      if(LLVM_INCLUDE_TESTS)
+        list(APPEND test_targets runtimes-test-depends check-runtimes)
+        foreach(component ${SUB_COMPONENTS})
+          list(APPEND SUB_CHECK_TARGETS check-${component})
+        endforeach()
+      endif()
+
+      llvm_ExternalProject_Add(runtimes
+                               ${CMAKE_CURRENT_SOURCE_DIR}
+                               DEPENDS ${deps}
+                               # Builtins were built separately above
+                               CMAKE_ARGS -DCOMPILER_RT_BUILD_BUILTINS=Off
+                                          -DLLVM_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
+                               PASSTHROUGH_PREFIXES ${prefixes}
+                               EXTRA_TARGETS ${extra_targets}
+                                              ${test_targets}
+                                              ${SUB_COMPONENTS}
+                                              ${SUB_CHECK_TARGETS}
+                                              ${SUB_INSTALL_TARGETS}
+                               USE_TOOLCHAIN
+                               ${EXTRA_ARGS})
+    else()
+      add_custom_target(runtimes)
+      add_custom_target(runtimes-configure)
+      add_custom_target(install-runtimes)
+      if(LLVM_INCLUDE_TESTS)
+        add_custom_target(check-runtimes)
+        add_custom_target(runtimes-test-depends)
+        set(test_targets "")
+      endif()
+
+      foreach(target ${LLVM_RUNTIME_TARGETS})
+        if(target STREQUAL "default")
+          set(target ${LLVM_DEFAULT_TARGET_TRIPLE})
+        endif()
+
+        runtime_register_target(${target})
+
+        add_dependencies(runtimes runtimes-${target})
+        add_dependencies(runtimes-configure runtimes-${target}-configure)
+        add_dependencies(install-runtimes install-runtimes-${target})
+        if(LLVM_INCLUDE_TESTS)
+          add_dependencies(check-runtimes check-runtimes-${target})
+          add_dependencies(runtimes-test-depends runtimes-test-depends-${target})
+        endif()
+      endforeach()
+    endif()
+
     # TODO: This is a hack needed because the libcxx headers are copied into the
     # build directory during configuration. Without that step the clang in the
     # build directory cannot find the C++ headers in certain configurations.
@@ -306,7 +435,7 @@
           sancov
           sanstats
         )
-      foreach(target ${test_targets} ${SUB_COMPONENT_CHECK_TARGETS})
+      foreach(target ${test_targets} ${SUB_CHECK_TARGETS})
         add_dependencies(${target} ${RUNTIMES_TEST_DEPENDS})
       endforeach()
     endif()
diff --git a/llvm/runtimes/Components.cmake.in b/llvm/runtimes/Components.cmake.in
index 6e24ac3..1d8fb7a 100644
--- a/llvm/runtimes/Components.cmake.in
+++ b/llvm/runtimes/Components.cmake.in
@@ -1,2 +1,3 @@
 set(SUB_COMPONENTS @SUB_COMPONENTS@)
+set(SUB_CHECK_TARGETS @SUB_CHECK_TARGETS@)
 set(SUB_INSTALL_TARGETS @SUB_INSTALL_TARGETS@)