diff --git a/cc/private/toolchain/libtool_check_unique.cc b/cc/private/toolchain/libtool_check_unique.cc
new file mode 100644
index 0000000..b90aa59
--- /dev/null
+++ b/cc/private/toolchain/libtool_check_unique.cc
@@ -0,0 +1,74 @@
+// Copyright 2020 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <regex>  // NOLINT
+#include <unordered_set>
+
+using std::ifstream;
+using std::regex;
+using std::string;
+using std::unordered_set;
+
+string getBasename(const string &path) {
+  // Assumes we're on an OS with "/" as the path separator
+  auto idx = path.find_last_of("/");
+  if (idx == string::npos) {
+    return path;
+  }
+  return path.substr(idx + 1);
+}
+
+// Returns 0 if there are no duplicate basenames in the object files (both via
+// -filelist as well as shell args), 1 otherwise
+int main(int argc, const char *argv[]) {
+  unordered_set<string> basenames;
+  const regex libRegex = regex(".*\\.a$");
+  const regex noArgFlags =
+      regex("-static|-s|-a|-c|-L|-T|-D|-no_warning_for_no_symbols");
+  const regex singleArgFlags = regex("-arch_only|-syslibroot|-o");
+  // Set i to 1 to skip executable path
+  for (int i = 1; argv[i] != nullptr; i++) {
+    const string arg = argv[i];
+    if (arg == "-filelist") {
+      ifstream list(argv[i + 1]);
+      for (string line; getline(list, line);) {
+        const string basename = getBasename(line);
+        const auto pair = basenames.insert(basename);
+        if (!pair.second) {
+          return EXIT_FAILURE;
+        }
+      }
+      list.close();
+      i++;
+    } else if (regex_match(arg, noArgFlags)) {
+    } else if (regex_match(arg, singleArgFlags)) {
+      i++;
+    } else if (arg[0] == '-') {
+      return EXIT_FAILURE;
+      // Unrecognized flag, let the wrapper deal with it
+    } else if (regex_match(arg, libRegex)) {
+      // Archive inputs can remain untouched, as they come from other targets.
+    } else {
+      const string basename = getBasename(arg);
+      const auto pair = basenames.insert(basename);
+      if (!pair.second) {
+        return EXIT_FAILURE;
+      }
+    }
+  }
+  return EXIT_SUCCESS;
+}
diff --git a/cc/private/toolchain/osx_cc_configure.bzl b/cc/private/toolchain/osx_cc_configure.bzl
index 88c6b3a..845a1f2 100644
--- a/cc/private/toolchain/osx_cc_configure.bzl
+++ b/cc/private/toolchain/osx_cc_configure.bzl
@@ -77,11 +77,16 @@
              error_msg)
 
 def configure_osx_toolchain(repository_ctx, overriden_tools):
-    """Configure C++ toolchain on macOS."""
+    """Configure C++ toolchain on macOS.
+
+    Args:
+      repository_ctx: The repository context.
+      overriden_tools: dictionary of overriden tools.
+    """
     paths = resolve_labels(repository_ctx, [
         "@rules_cc//cc/private/toolchain:osx_cc_wrapper.sh.tpl",
+        "@rules_cc//cc/private/toolchain:libtool_check_unique.cc",
         "@bazel_tools//tools/objc:libtool.sh",
-        "@bazel_tools//tools/objc:libtool_check_unique.cc",
         "@bazel_tools//tools/objc:make_hashed_objlist.py",
         "@bazel_tools//tools/objc:xcrunwrapper.sh",
         "@bazel_tools//tools/osx/crosstool:BUILD.tpl",
@@ -137,7 +142,7 @@
             "cc_toolchain_config.bzl",
         )
         libtool_check_unique_src_path = str(repository_ctx.path(
-            paths["@bazel_tools//tools/objc:libtool_check_unique.cc"],
+            paths["@rules_cc//cc/private/toolchain:libtool_check_unique.cc"],
         ))
         compile_cc_file(repository_ctx, libtool_check_unique_src_path, "libtool_check_unique")
         wrapped_clang_src_path = str(repository_ctx.path(