Index: libcxx/test/lit.site.cfg.in
===================================================================
--- libcxx/test/lit.site.cfg.in
+++ libcxx/test/lit.site.cfg.in
@@ -36,6 +36,9 @@
 config.pstl_src_root            = "@ParallelSTL_SOURCE_DIR@" if @LIBCXX_ENABLE_PARALLEL_ALGORITHMS@ else None
 config.pstl_obj_root            = "@ParallelSTL_BINARY_DIR@" if @LIBCXX_ENABLE_PARALLEL_ALGORITHMS@ else None
 
+# Code signing
+config.llvm_codesign_identity   = "@LLVM_CODESIGNING_IDENTITY@"
+
 # Let the main config do the real work.
 config.loaded_site_config = True
 lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")
Index: libcxx/utils/libcxx/compiler.py
===================================================================
--- libcxx/utils/libcxx/compiler.py
+++ libcxx/utils/libcxx/compiler.py
@@ -17,12 +17,13 @@
     CM_Compile = 2
     CM_Link = 3
 
-    def __init__(self, path, flags=None, compile_flags=None, link_flags=None,
+    def __init__(self, config, path, flags=None, compile_flags=None, link_flags=None,
                  warning_flags=None, verify_supported=None,
                  verify_flags=None, use_verify=False,
                  modules_flags=None, use_modules=False,
                  use_ccache=False, use_warnings=False, compile_env=None,
                  cxx_type=None, cxx_version=None):
+        self.libcxx_config = config
         self.source_lang = 'c++'
         self.path = path
         self.flags = list(flags or [])
@@ -163,17 +164,34 @@
                                                   cwd=cwd)
         return cmd, out, err, rc
 
-    def link(self, source_files, out=None, flags=[], cwd=None):
-        cmd = self.linkCmd(source_files, out, flags)
+    def link(self, source_files, exec_path=None, flags=[], cwd=None):
+        cmd = self.linkCmd(source_files, exec_path, flags)
         out, err, rc = libcxx.util.executeCommand(cmd, env=self.compile_env,
                                                   cwd=cwd)
+        cs_cmd, cs_out, cs_err, cs_rc = self.codesign(exec_path, cwd)
+        if cs_rc != 0:
+            return cs_cmd, cs_out, cs_err, cs_rc
         return cmd, out, err, rc
 
-    def compileLink(self, source_files, out=None, flags=[],
+    def compileLink(self, source_files, exec_path=None, flags=[],
                     cwd=None):
-        cmd = self.compileLinkCmd(source_files, out, flags)
+        cmd = self.compileLinkCmd(source_files, exec_path, flags)
         out, err, rc = libcxx.util.executeCommand(cmd, env=self.compile_env,
                                                   cwd=cwd)
+        cs_cmd, cs_out, cs_err, cs_rc = self.codesign(exec_path, cwd)
+        if cs_rc != 0:
+            return cs_cmd, cs_out, cs_err, cs_rc
+        return cmd, out, err, rc
+
+    def codesign(self, exec_path, cwd=None):
+        null_op = [], '', '', 0
+        if not exec_path:
+            return null_op
+        codesign_ident = self.libcxx_config.get_lit_conf('llvm_codesign_identity', '')
+        if not codesign_ident:
+            return null_op
+        cmd = ['xcrun', 'codesign', '-s', codesign_ident, exec_path]
+        out, err, rc = libcxx.util.executeCommand(cmd, cwd=cwd)
         return cmd, out, err, rc
 
     def compileLinkTwoSteps(self, source_file, out=None, object_file=None,
@@ -193,7 +211,7 @@
                 return cc_cmd, cc_stdout, cc_stderr, rc
 
             link_cmd, link_stdout, link_stderr, rc = self.link(
-                object_file, out=out, flags=flags, cwd=cwd)
+                object_file, exec_path=out, flags=flags, cwd=cwd)
             return (cc_cmd + ['&&'] + link_cmd, cc_stdout + link_stdout,
                     cc_stderr + link_stderr, rc)
 
Index: libcxx/utils/libcxx/test/config.py
===================================================================
--- libcxx/utils/libcxx/test/config.py
+++ libcxx/utils/libcxx/test/config.py
@@ -228,7 +228,7 @@
         if not cxx:
             self.lit_config.fatal('must specify user parameter cxx_under_test '
                                   '(e.g., --param=cxx_under_test=clang++)')
-        self.cxx = CXXCompiler(cxx) if not self.cxx_is_clang_cl else \
+        self.cxx = CXXCompiler(self, cxx) if not self.cxx_is_clang_cl else \
                    self._configure_clang_cl(cxx)
         cxx_type = self.cxx.type
         if cxx_type is not None:
@@ -260,7 +260,7 @@
         link_flags = _prefixed_env_list('LIB', '-L')
         for path in _split_env_var('LIB'):
             self.add_path(self.exec_env, path)
-        return CXXCompiler(clang_path, flags=flags,
+        return CXXCompiler(self, clang_path, flags=flags,
                            compile_flags=compile_flags,
                            link_flags=link_flags)