message: add terminator to empty block
diff: @@ -52,7 +52,10 @@ def add_terminators(blocks):
  to all blocks (avoiding "fall-through" control flow transfers).
  """
  for i, block in enumerate(blocks.values()):
  - if block[-1]['op'] not in TERMINATORS:
  + if not block:
  + dest = list(blocks.keys())[i + 1]
  + block.append({'op': 'jmp', 'args': [dest]})
  + elif block[-1]['op'] not in TERMINATORS:
  if i == len(blocks) - 1:
  # In the last block, return.
  block.append({'op': 'ret', 'args': []})
  