Index: clang/cmake/caches/Fuchsia-stage2.cmake
===================================================================
--- clang/cmake/caches/Fuchsia-stage2.cmake
+++ clang/cmake/caches/Fuchsia-stage2.cmake
@@ -27,12 +27,24 @@
 set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only -DNDEBUG" CACHE STRING "")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only -DNDEBUG" CACHE STRING "")
 
+set(FUCHSIA_RUNTIMES_ENABLE_ASSERTIONS ON CACHE BOOL "")
+set(FUCHSIA_RUNTIMES_BUILD_TYPE Release CACHE STRING "")
+set(FUCHSIA_BUILTINS_BUILD_TYPE Release CACHE STRING "")
+
 set(LLVM_BUILTIN_TARGETS "default;x86_64-fuchsia;aarch64-fuchsia" CACHE STRING "")
 
 # Set the per-target builtins options.
 foreach(target x86_64;aarch64)
-  set(BUILTINS_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_UNIX 1 CACHE BOOL "")
   set(BUILTINS_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_BUILD_TYPE ${FUCHSIA_BUILTINS_BUILD_TYPE} CACHE STRING "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_ASM_FLAGS ${FUCHSIA_${target}_C_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_C_FLAGS ${FUCHSIA_${target}_C_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_CXX_FLAGS ${FUCHSIA_${target}_CXX_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_EXE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_SHARED_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_MODULE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(BUILTINS_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
 endforeach()
 
 set(LLVM_RUNTIME_TARGETS "default;x86_64-fuchsia;aarch64-fuchsia;x86_64-fuchsia-asan:x86_64-fuchsia;aarch64-fuchsia-asan:aarch64-fuchsia" CACHE STRING "")
@@ -54,10 +66,18 @@
 
 # Set the per-target runtimes options.
 foreach(target x86_64;aarch64)
-  set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_WITH_INSTALL_RPATH ON CACHE BOOL "")
-  set(RUNTIMES_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
-  set(RUNTIMES_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
   set(RUNTIMES_${target}-fuchsia_UNIX 1 CACHE BOOL "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_BUILD_TYPE ${FUCHSIA_RUNTIMES_BUILD_TYPE} CACHE STRING "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_ASM_FLAGS ${FUCHSIA_${target}_C_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_C_FLAGS ${FUCHSIA_${target}_C_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_CXX_FLAGS ${FUCHSIA_${target}_CXX_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_EXE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_SHARED_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_MODULE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_COMPILER_RT_TEST_COMPILER_CFLAGS ${FUCHSIA_${target}_C_FLAGS} CACHE PATH "")
+  set(RUNTIMES_${target}-fuchsia_LLVM_ENABLE_ASSERTIONS ${FUCHSIA_RUNTIMES_ENABLE_ASSERTIONS} CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBUNWIND_ENABLE_STATIC OFF CACHE BOOL "")
   set(RUNTIMES_${target}-fuchsia_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
Index: clang/cmake/caches/Fuchsia.cmake
===================================================================
--- clang/cmake/caches/Fuchsia.cmake
+++ clang/cmake/caches/Fuchsia.cmake
@@ -40,9 +40,11 @@
   install-distribution
   clang CACHE STRING "")
 
-foreach(target x86_64;aarch64)
-  if(FUCHSIA_${target}_SYSROOT)
-    list(APPEND EXTRA_ARGS -DFUCHSIA_${target}_SYSROOT=${FUCHSIA_${target}_SYSROOT})
+get_cmake_property(variableNames VARIABLES)
+foreach(variableName ${variableNames})
+  if(variableName MATCHES "^STAGE2_")
+    string(REPLACE "STAGE2_" "" new_name ${variableName})
+    list(APPEND EXTRA_ARGS "-D${new_name}=${${variableName}}")
   endif()
 endforeach()