func testEndToEnd(t *testing.T, goarch, file string) {
	input := filepath.Join("testdata", file+".s")
	architecture, ctxt := setArch(goarch)
	architecture.Init(ctxt)
	lexer := lex.NewLexer(input)
	parser := NewParser(ctxt, architecture, lexer)
	pList := new(obj.Plist)
	var ok bool
	testOut = new(strings.Builder) // The assembler writes test output to this buffer.
	ctxt.Bso = bufio.NewWriter(os.Stdout)
	ctxt.IsAsm = true

	pkgPrefix     string           // Prefix to add to local symbols.
	errorWriter   io.Writer
}

type Patch struct {
	addr  *obj.Addr
	label string
}

func NewParser(ctxt *obj.Link, ar *arch.Arch, lexer lex.TokenReader) *Parser {
	pkgPrefix := obj.UnlinkablePkg
	if ctxt != nil {
		pkgPrefix = objabi.PathToPrefix(ctxt.Pkgpath)
	}
	return &Parser{
		ctxt:        ctxt,