private BasicBlock labelToBlock(int label) {
    int idx = labelToResultIndex(label);

    if (idx < 0) {
      throw new IllegalArgumentException("no such label " + Hex.u2(label));
    }

    return result.get(idx);
  }
Searches {@link #result} for a block with the given label. Returns it if found, or throws an
exception if there is no such block.

@param label the label to look for
@return {@code non-null;} the block with the given label
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/code/Ropper.java