if f == nil && fb == nil {
			continue
		}
		var actual string
		if f != nil {
			actual = string(f([]byte(tc.in), tc.arg))
		} else {
			actual = string(fb([]byte(tc.in), []byte(tc.arg)))
		}
		if actual != tc.out {
			t.Errorf("%s(%q, %q) = %q; want %q", name, tc.in, tc.arg, actual, tc.out)
		}
	}

	for _, tc := range trimNilTests {
		name := tc.f
		f, fb := toFn(name)

<code>8(FP)</code> is the second (on a 64-bit machine), and so on.
However, when referring to a function argument this way, it is necessary to place a name
at the beginning, as in <code>first_arg+0(FP)</code> and <code>second_arg+8(FP)</code>.
(The meaning of the offset—offset from the frame pointer—distinct
from its use with <code>SB</code>, where it is an offset from the symbol.)

		printUsage(os.Stdout)
		os.Exit(0)
	}

	flag.Usage = usage
	flag.Parse()
	if flag.NArg() != 1 {
		usage()
	}

	f, err := objfile.Open(flag.Arg(0))
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	tab, err := f.PCLineTable()
	if err != nil {
		log.Fatalf("reading %s: %v", flag.Arg(0), err)
	}

	stdin := bufio.NewScanner(os.Stdin)
	stdout := bufio.NewWriter(os.Stdout)

two:
	RET
TEXT ·a12(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	JMP one
two:
	ORQ R15, R15
	RET
one:
	MOVL $0, R15
	JMP two

// Ensure 3-arg instructions get GOT-rewritten without errors.
// See issue 58735.
TEXT ·a13(SB), 0, $0-0
	MULXQ runtime·writeBarrier(SB), AX, CX
	RET

// Various special cases in the use-R15-after-global-access-when-dynlinking check.