code: func adjacent(m1, m2 *Mapping) bool {
  	if m1.File != "" && m2.File != "" {
  		if m1.File != m2.File {
  			return false
  		}
  	}
  	if m1.BuildID != "" && m2.BuildID != "" {
  		if m1.BuildID != m2.BuildID {
  			return false
  		}
  	}
  	if m1.Limit != m2.Start {
  		return false
  	}
  	if m1.Offset != 0 && m2.Offset != 0 {
  		offset := m1.Offset + (m1.Limit - m1.Start)
  		if offset != m2.Offset {
  			return false
  		}
  	}
  	return true
  }
docs: // adjacent returns whether two mapping entries represent the same
  // mapping that has been split into two. Check that their addresses are adjacent,
  // and if the offsets match, if they are available.