diff --git a/libc/tools/genfunctosyscallnrs.py b/libc/tools/genfunctosyscallnrs.py
new file mode 100755
index 0000000..6a456f2
--- /dev/null
+++ b/libc/tools/genfunctosyscallnrs.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+
+import argparse
+import collections
+import logging
+import os
+import re
+import subprocess
+import textwrap
+
+from gensyscalls import SysCallsTxtParser
+from genseccomp import parse_syscall_NRs
+
+def load_syscall_names_from_file(file_path, architecture):
+  parser = SysCallsTxtParser()
+  parser.parse_open_file(open(file_path))
+  arch_map = {}
+  for syscall in parser.syscalls:
+    if syscall.get(architecture):
+      arch_map[syscall["func"]] = syscall["name"];
+
+  return arch_map
+
+def gen_syscall_nrs(out_file, base_syscall_file, syscall_NRs):
+  for arch in ('arm', 'arm64', 'mips', 'mips64', 'x86', 'x86_64'):
+    base_names = load_syscall_names_from_file(base_syscall_file, arch)
+
+    for func,syscall in base_names.iteritems():
+      out_file.write("#define __" + arch + "_" + func + " " + str(syscall_NRs[arch][syscall]) + ";\n")
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Generates a mapping of bionic functions to system call numbers per architecture.")
+  parser.add_argument("--verbose", "-v", help="Enables verbose logging.")
+  parser.add_argument("--out-dir",
+                      help="The output directory for the output files")
+  parser.add_argument("base_file", metavar="base-file", type=str,
+                      help="The path of the base syscall list (SYSCALLS.TXT).")
+  parser.add_argument("files", metavar="FILE", type=str, nargs="+",
+                      help=("A syscall name-number mapping file for an architecture.\n"))
+  args = parser.parse_args()
+
+  if args.verbose:
+    logging.basicConfig(level=logging.DEBUG)
+  else:
+    logging.basicConfig(level=logging.INFO)
+
+  syscall_files = []
+  syscall_NRs = {}
+  for filename in args.files:
+    m = re.search(r"libseccomp_gen_syscall_nrs_([^/]+)", filename)
+    syscall_NRs[m.group(1)] = parse_syscall_NRs(filename)
+
+  output_path = os.path.join(args.out_dir, "func_to_syscall_nrs.h")
+  with open(output_path, "w") as output_file:
+    gen_syscall_nrs(out_file=output_file,
+             syscall_NRs=syscall_NRs, base_syscall_file=args.base_file)
+
+if __name__ == "__main__":
+  main()