diff --git a/clang/test/CMakeLists.txt b/clang/test/CMakeLists.txt
--- a/clang/test/CMakeLists.txt
+++ b/clang/test/CMakeLists.txt
@@ -3,6 +3,7 @@
 
 llvm_canonicalize_cmake_booleans(
   CLANG_BUILD_EXAMPLES
+  CLANG_BUILT_STANDALONE
   CLANG_DEFAULT_PIE_ON_LINUX
   CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL
   CLANG_ENABLE_ARCMT
diff --git a/clang/test/lit.site.cfg.py.in b/clang/test/lit.site.cfg.py.in
--- a/clang/test/lit.site.cfg.py.in
+++ b/clang/test/lit.site.cfg.py.in
@@ -37,6 +37,7 @@
 config.has_plugins = @CLANG_PLUGIN_SUPPORT@
 config.clang_vendor_uti = "@CLANG_VENDOR_UTI@"
 config.llvm_external_lit = path(r"@LLVM_EXTERNAL_LIT@")
+config.standalone_build = @CLANG_BUILT_STANDALONE@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
diff --git a/clang/test/utils/update_cc_test_checks/lit.local.cfg b/clang/test/utils/update_cc_test_checks/lit.local.cfg
--- a/clang/test/utils/update_cc_test_checks/lit.local.cfg
+++ b/clang/test/utils/update_cc_test_checks/lit.local.cfg
@@ -10,27 +10,36 @@
     from pipes import quote as shell_quote
 
 
-config.test_format = lit.formats.ShTest(execute_external=False)
-config.suffixes = ['.test']
-
-clang_path = os.path.join(config.clang_tools_dir, 'clang')
-extra_args = '--clang ' + shell_quote(clang_path)
-opt_path = os.path.join(config.llvm_tools_dir, 'opt')
-extra_args += ' --opt ' + shell_quote(opt_path)
-script_path = os.path.join(config.llvm_src_root, 'utils',
-                           'update_cc_test_checks.py')
-assert os.path.isfile(script_path)
-# Windows: llvm-lit.py, Linux: llvm-lit
-if config.llvm_external_lit:
-    lit = config.llvm_external_lit
+if config.standalone_build:
+    # These tests require the update_cc_test_checks.py script from the llvm
+    # source tree, so skip these tests if we are doing standalone builds.
+    # These tests are only relevant to developers working with the
+    # update_cc_test_checks.py tool; they don't provide any coverage
+    # for any of the clang source code.
+    config.unsupported = True
 else:
-    lit = shell_quote(glob.glob(os.path.join(config.llvm_tools_dir, 'llvm-lit*'))[0])
-python = shell_quote(config.python_executable)
-config.substitutions.append(
-    ('%update_cc_test_checks', "%s %s %s" % (
-        python, shell_quote(script_path), extra_args)))
-config.substitutions.append(
-    ('%clang_tools_dir', shell_quote(config.clang_tools_dir)))
-config.substitutions.append(
-    ('%lit', "%s %s -Dclang_lit_site_cfg=%s -j1 -vv" % (
-        python, lit, shell_quote(config.clang_lit_site_cfg))))
+
+    config.test_format = lit.formats.ShTest(execute_external=False)
+    config.suffixes = ['.test']
+
+    clang_path = os.path.join(config.clang_tools_dir, 'clang')
+    extra_args = '--clang ' + shell_quote(clang_path)
+    opt_path = os.path.join(config.llvm_tools_dir, 'opt')
+    extra_args += ' --opt ' + shell_quote(opt_path)
+    script_path = os.path.join(config.llvm_src_root, 'utils',
+                               'update_cc_test_checks.py')
+    assert os.path.isfile(script_path)
+    # Windows: llvm-lit.py, Linux: llvm-lit
+    if config.llvm_external_lit:
+        lit = config.llvm_external_lit
+    else:
+        lit = shell_quote(glob.glob(os.path.join(config.llvm_tools_dir, 'llvm-lit*'))[0])
+    python = shell_quote(config.python_executable)
+    config.substitutions.append(
+        ('%update_cc_test_checks', "%s %s %s" % (
+            python, shell_quote(script_path), extra_args)))
+    config.substitutions.append(
+        ('%clang_tools_dir', shell_quote(config.clang_tools_dir)))
+    config.substitutions.append(
+        ('%lit', "%s %s -Dclang_lit_site_cfg=%s -j1 -vv" % (
+            python, lit, shell_quote(config.clang_lit_site_cfg))))