pos := sf.pos + sourceFileNumPlusBuildConstraints
	n := sf.d.intAt(pos)
	pos += 4
	ret := make([]string, n)
	for i := 0; i < n; i++ {
		ret[i] = sf.d.stringAt(pos)
		pos += 4
	}
	return ret
}

func (sf *sourceFile) importsOffset() int {
	pos := sf.pos + sourceFileNumPlusBuildConstraints
	n := sf.d.intAt(pos)
	// each build constraint is 1 uint32
	return pos + 4 + n*4
}