code: def _compiler_bridge_cache_dir(self):
      
      hasher = sha1()
      for cp_entry in [self.zinc, self.compiler_interface, self.compiler_bridge]:
        hasher.update(os.path.relpath(cp_entry, self._workdir()).encode('utf-8'))
      key = hasher.hexdigest()[:12]
  
      return os.path.join(self._workdir(), 'zinc', 'compiler-bridge', key)
docs: A directory where we can store compiled copies of the `compiler-bridge`.
  
      The compiler-bridge is specific to each scala version.
      Currently we compile the `compiler-bridge` only once, while bootstrapping.
      Then, we store it in the working directory under .pants.d/zinc/<cachekey>, where
      <cachekey> is calculated using the locations of zinc, the compiler interface,
      and the compiler bridge.