Index: test/builtins/CMakeLists.txt
===================================================================
--- test/builtins/CMakeLists.txt
+++ test/builtins/CMakeLists.txt
@@ -13,6 +13,8 @@
 
 include(builtin-config-ix)
 
+pythonize_bool(MSVC)
+
 #TODO: Add support for Apple.
 if (NOT APPLE)
 foreach(arch ${BUILTIN_SUPPORTED_ARCH})
Index: test/builtins/Unit/lit.cfg
===================================================================
--- test/builtins/Unit/lit.cfg
+++ test/builtins/Unit/lit.cfg
@@ -24,7 +24,12 @@
 config.test_source_root = os.path.dirname(__file__)
 
 # Path to the static library
-base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins-%s.a "
+is_msvc = getattr(config, "builtins_is_msvc", False)
+if is_msvc:
+  base_lib = os.path.join(config.compiler_rt_libdir, "clang_rt.builtins-%s.lib"
+    % config.target_arch)
+else:
+  base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins-%s.a"
     % config.target_arch)
 
 builtins_source_dir = os.path.join(
Index: test/builtins/Unit/lit.site.cfg.in
===================================================================
--- test/builtins/Unit/lit.site.cfg.in
+++ test/builtins/Unit/lit.site.cfg.in
@@ -4,7 +4,7 @@
 config.builtins_lit_source_dir = "@BUILTINS_LIT_SOURCE_DIR@/Unit"
 config.target_cflags = "@BUILTINS_TEST_TARGET_CFLAGS@"
 config.target_arch = "@BUILTINS_TEST_TARGET_ARCH@"
-
+config.builtins_is_msvc = @MSVC_PYBOOL@
 # Load common config for all compiler-rt lit tests.
 lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")