Index: src/CMakeLists.txt
===================================================================
--- src/CMakeLists.txt
+++ src/CMakeLists.txt
@@ -168,6 +168,22 @@
                           POSITION_INDEPENDENT_CODE
                             ON)
   list(APPEND LIBCXXABI_TARGETS "cxxabi_static")
+  # Attempt to merge the libc++abi.a archive and the libunwind.a archive into one.
+  if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_ENABLE_STATIC_UNWINDER)
+    if (TARGET unwind_static OR HAVE_LIBUNWIND)
+      set(MERGE_ARCHIVES_ABI_TARGET "$<TARGET_LINKER_FILE:unwind_static>")
+    endif()
+    add_custom_command(TARGET cxxabi_static POST_BUILD
+    COMMAND
+      ${PYTHON_EXECUTABLE} ${LIBCXXABI_SOURCE_DIR}/utils/merge_archives.py
+    ARGS
+      -o $<TARGET_LINKER_FILE:cxxabi_static>
+      --ar "${CMAKE_AR}"
+      "$<TARGET_LINKER_FILE:cxxabi_static>"
+      "${MERGE_ARCHIVES_ABI_TARGET}"
+    WORKING_DIRECTORY ${LIBCXXABI_BUILD_DIR}
+    )
+  endif()
 endif()
 
 # Add a meta-target for both libraries.
Index: utils/merge_archives.py
===================================================================
--- /dev/null
+++ utils/merge_archives.py
@@ -0,0 +1,136 @@
+#!/usr/bin/env python
+#===----------------------------------------------------------------------===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is dual licensed under the MIT and the University of Illinois Open
+# Source Licenses. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===##
+
+from argparse import ArgumentParser
+from ctypes.util import find_library
+import distutils.spawn
+import glob
+import tempfile
+import os
+import shutil
+import subprocess
+import signal
+import sys
+
+temp_directory_root = None
+def exit_with_cleanups(status):
+    if temp_directory_root is not None:
+        shutil.rmtree(temp_directory_root)
+    sys.exit(status)
+
+def print_and_exit(msg):
+    sys.stderr.write(msg + '\n')
+    exit_with_cleanups(1)
+
+def find_and_diagnose_missing(lib, search_paths):
+    if os.path.exists(lib):
+        return os.path.abspath(lib)
+    if not lib.startswith('lib') or not lib.endswith('.a'):
+        print_and_exit(("input file '%s' not not name a static library. "
+                       "It should start with 'lib' and end with '.a") % lib)
+    for sp in search_paths:
+        assert type(sp) is list and len(sp) == 1
+        path = os.path.join(sp[0], lib)
+        if os.path.exists(path):
+            return os.path.abspath(path)
+    print_and_exit("input '%s' does not exist" % lib)
+
+
+def execute_command(cmd, cwd=None):
+    """
+    Execute a command, capture and return its output.
+    """
+    kwargs = {
+        'stdin': subprocess.PIPE,
+        'stdout': subprocess.PIPE,
+        'stderr': subprocess.PIPE,
+        'cwd': cwd
+    }
+    p = subprocess.Popen(cmd, **kwargs)
+    out, err = p.communicate()
+    exitCode = p.wait()
+    if exitCode == -signal.SIGINT:
+        raise KeyboardInterrupt
+    return out, err, exitCode
+
+
+def execute_command_verbose(cmd, cwd=None, verbose=False):
+    """
+    Execute a command and print its output on failure.
+    """
+    out, err, exitCode = execute_command(cmd, cwd=cwd)
+    if exitCode != 0 or verbose:
+        report = "Command: %s\n" % ' '.join(["'%s'" % a for a in cmd])
+        if exitCode != 0:
+            report += "Exit Code: %d\n" % exitCode
+        if out:
+            report += "Standard Output:\n--\n%s--" % out
+        if err:
+            report += "Standard Error:\n--\n%s--" % err
+        if exitCode != 0:
+            report += "\n\nFailed!"
+        sys.stderr.write('%s\n' % report)
+        if exitCode != 0:
+            exit_with_cleanups(exitCode)
+
+def main():
+    parser = ArgumentParser(
+        description="Merge multiple archives into a single library")
+    parser.add_argument(
+        '-v', '--verbose', dest='verbose', action='store_true', default=False)
+    parser.add_argument(
+        '-o', '--output', dest='output', required=True,
+        help='The output file. stdout is used if not given',
+        type=str, action='store')
+    parser.add_argument(
+        '-L', dest='search_paths',
+        help='Paths to search for the libraries along', action='append',
+        nargs=1)
+    parser.add_argument(
+        '--ar', dest='ar_exe', required=False,
+        help='The ar executable to use, finds \'ar\' in the path if not given',
+        type=str, action='store')
+    parser.add_argument(
+        'archives', metavar='archives',  nargs='+',
+        help='The archives to merge')
+
+    args = parser.parse_args()
+
+    ar_exe = args.ar_exe
+    if not ar_exe:
+        ar_exe = distutils.spawn.find_executable('ar')
+    if not ar_exe:
+        print_and_exit("failed to find 'ar' executable")
+
+    if len(args.archives) < 2:
+        print_and_exit('fewer than 2 inputs provided')
+    archives = [find_and_diagnose_missing(ar, args.search_paths)
+                for ar in args.archives]
+    print ('Merging archives: %s' % archives)
+    if not os.path.exists(os.path.dirname(args.output)):
+        print_and_exit("output path doesn't exist: '%s'" % args.output)
+
+    global temp_directory_root
+    temp_directory_root = tempfile.mkdtemp('.libcxx.merge.archives')
+
+    for arc in archives:
+        execute_command_verbose([ar_exe, 'x', arc], cwd=temp_directory_root,
+                                verbose=args.verbose)
+
+    files = glob.glob(os.path.join(temp_directory_root, '*.o*'))
+    if not files:
+        print_and_exit('Failed to glob for %s' % temp_directory_root)
+    cmd = [ar_exe, 'qcs', args.output] + files
+    execute_command_verbose(cmd, cwd=temp_directory_root, verbose=args.verbose)
+
+
+if __name__ == '__main__':
+    main()
+    exit_with_cleanups(0)