start := b.pb.startMessage()
	b.pb.uint64Opt(tagLine_FunctionID, funcID)
	b.pb.int64Opt(tagLine_Line, line)
	b.pb.endMessage(tag, start)
}

// pbMapping encodes a Mapping message to b.pb.
func (b *profileBuilder) pbMapping(tag int, id, base, limit, offset uint64, file, buildID string, hasFuncs bool) {
	start := b.pb.startMessage()
	b.pb.uint64Opt(tagMapping_ID, id)
	b.pb.uint64Opt(tagMapping_Start, base)