Index: runtimes/CMakeLists.txt
===================================================================
--- runtimes/CMakeLists.txt
+++ runtimes/CMakeLists.txt
@@ -55,14 +55,19 @@
 
   # Setting these variables will allow the sub-build to put their outputs into
   # the library and bin directories of the top-level build.
-  set(LLVM_LIBRARY_OUTPUT_INTDIR ${LLVM_LIBRARY_DIR})
-  set(LLVM_RUNTIME_OUTPUT_INTDIR ${LLVM_TOOLS_BINARY_DIR})
+  if(LLVM_RUNTIMES_TARGET)
+    set(LLVM_LIBRARY_OUTPUT_INTDIR "${LLVM_LIBRARY_DIR}/${LLVM_RUNTIMES_TARGET}")
+    set(LLVM_RUNTIME_OUTPUT_INTDIR "${LLVM_TOOLS_BINARY_DIR}/${LLVM_RUNTIMES_TARGET}")
+  else()
+    set(LLVM_LIBRARY_OUTPUT_INTDIR ${LLVM_LIBRARY_DIR})
+    set(LLVM_RUNTIME_OUTPUT_INTDIR ${LLVM_TOOLS_BINARY_DIR})
+  endif()
 
   # This variable makes sure that e.g. llvm-lit is found.
   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 ${CMAKE_REQUIRED_FLAGS})
@@ -96,6 +101,12 @@
     # The subdirectories need to treat this as standalone builds
     set(${canon_name}_STANDALONE_BUILD On)
 
+    if(LLVM_RUNTIMES_TARGET)
+      if(NOT "${entry}" MATCHES "compiler-rt")
+        set(${canon_name}_INSTALL_PATH "${CMAKE_INSTALL_PREFIX}/lib/${LLVM_RUNTIMES_TARGET}" CACHE PATH "" FORCE)
+      endif()
+    endif()
+
     # Setting a variable to let sub-projects detect which other projects
     # will be included under here.
     set(HAVE_${canon_name} On)
@@ -190,6 +201,10 @@
       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)
@@ -247,39 +262,108 @@
   endforeach()
 
   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)
+      foreach(runtime_name ${runtime_names})
+        list(APPEND extra_targets
+          ${runtime_name}
+          install-${runtime_name}
+          check-${runtime_name})
+      endforeach()
 
-    foreach(runtime_name ${runtime_names})
-      list(APPEND extra_targets
-        ${runtime_name}
-        install-${runtime_name}
-        check-${runtime_name})
-    endforeach()
+      if(LLVM_INCLUDE_TESTS)
+        set(test_targets runtimes-test-depends check-runtimes)
+        foreach(component ${SUB_COMPONENTS})
+          list(APPEND SUB_COMPONENT_CHECK_TARGETS check-${component})
+        endforeach()
+      endif()
 
-    if(LLVM_INCLUDE_TESTS)
-      set(test_targets runtimes-test-depends check-runtimes)
-      foreach(component ${SUB_COMPONENTS})
-        list(APPEND SUB_COMPONENT_CHECK_TARGETS check-${component})
+      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_COMPONENT_CHECK_TARGETS}
+                                              ${SUB_INSTALL_TARGETS}
+                               USE_TOOLCHAIN
+                               ${EXTRA_ARGS})
+    else()
+      get_cmake_property(variableNames VARIABLES)
+      add_custom_target(runtimes)
+      add_custom_target(install-runtimes)
+      if(LLVM_INCLUDE_TESTS)
+        add_custom_target(check-runtimes)
+        add_custom_target(runtimes-test-depends)
+      endif()
+      foreach(target ${LLVM_RUNTIME_TARGETS})
+        if(target STREQUAL "default")
+          set(target ${LLVM_DEFAULT_TARGET_TRIPLE})
+        endif()
+
+        foreach(runtime_name ${runtime_names})
+          list(APPEND ${target}_extra_targets
+            ${runtime_name}-${target}
+            install-${runtime_name}-${target}
+            check-${runtime_name}-${target})
+        endforeach()
+
+        if(LLVM_INCLUDE_TESTS)
+          set(${target}_test_targets runtimes-test-depends-${target} check-runtimes-${target})
+          foreach(component ${SUB_COMPONENTS})
+            list(APPEND SUB_COMPONENT_CHECK_TARGETS check-${component}-${target})
+          endforeach()
+        endif()
+
+        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 ${${target}_extra_targets}
+                                               ${${target}_test_targets}
+                                               ${SUB_COMPONENTS}
+                                               ${SUB_COMPONENT_CHECK_TARGETS}
+                                               ${SUB_INSTALL_TARGETS}
+                                 USE_TOOLCHAIN
+                                 ${EXTRA_ARGS})
+
+        add_dependencies(runtimes runtimes-${target})
+        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()
 
-    # 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
-                             ${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_COMPONENT_CHECK_TARGETS}
-                                            ${SUB_INSTALL_TARGETS}
-                             USE_TOOLCHAIN
-                             ${EXTRA_ARGS})
-    
     # 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.