message: Tolerate empty final block
diff: @@ -51,11 +51,14 @@ def add_terminators(blocks):
  """
  for i, block in enumerate(blocks.values()):
  if not block:
  + if i == len(blocks) - 1:
  + # In the last block, return.
  + block.append({'op': 'ret', 'args': []})
  + else:
  dest = list(blocks.keys())[i + 1]
  block.append({'op': 'jmp', 'labels': [dest]})
  elif block[-1]['op'] not in TERMINATORS:
  if i == len(blocks) - 1:
  - # In the last block, return.
  block.append({'op': 'ret', 'args': []})
  else:
  # Otherwise, jump to the next block.
  