new_contents: #!/usr/bin/env python
  
  import argparse
  import os
  import re
  import shlex
  import subprocess
  import sys
  
  
  ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
  LLVM_TEST_DIR = os.path.join(ROOT_DIR, 'third_party', 'llvm', 'test', 'CodeGen',
                               'WebAssembly')
  S_TEST_DIR = ROOT_DIR
  LLVM_DIR = os.path.join(ROOT_DIR, 'third_party', 'llvm')
  BIN_DIR = os.path.join(LLVM_DIR, 'build', 'bin')
  
  
  def FindTestFiles(directory, ext):
      tests = []
      for root, dirs, files in os.walk(directory):
          for f in files:
              path = os.path.join(root, f)
              if os.path.splitext(f)[1] == ext:
                  tests.append(path)
      tests.sort()
      return tests
  
  
  def GetRunLine(test):
      run_line = ''
      with open(test) as test_file:
          for line in test_file.readlines():
              m = re.match(r'; RUN: (.*?)(\\?)$', line)
              if m:
                  run_line += m.group(1)
                  if not m.group(2):
                      break
      # Remove FileCheck
      run_line = re.sub(r'\|\s*FileCheck.*$', '', run_line)
      # Remove pipe input
      run_line = re.sub(r'<\s*%s', '', run_line)
      # Remove stderr > stdout redirect
      run_line = re.sub(r'2>&1', '', run_line)
      return run_line
  
  
  def main(args):
      parser = argparse.ArgumentParser()
      options = parser.parse_args(args)
  
      tests = FindTestFiles(LLVM_TEST_DIR, '.ll')
      for ll_test in tests:
          name_noext = os.path.splitext(os.path.basename(ll_test))[0]
          s = os.path.join(S_TEST_DIR, name_noext + '.s')
          run_line = GetRunLine(ll_test)
          cmd = shlex.split(run_line)
          cmd.extend([ll_test, '-o', s])
          # Don't run if the command isn't llc. Some are opt and they don't
          # generate .s files.
          if cmd[0] != 'llc':
              continue
          cmd[0] = os.path.join(BIN_DIR, cmd[0])
          subprocess.check_call(cmd)
  
  
  if __name__ == '__main__':
      sys.exit(main(sys.argv[1:]))
  
subject: Check in the llvm-to-s.py script used to generate the tests.