"".TestEmpty STEXT nosplit size=22 args=0x18 locals=0x0
        0x0000 00000 (/home/shansen/foo.go:14)  TEXT    "".TestEmpty(SB), NOSPLIT, $0-24
        0x0000 00000 (/home/shansen/foo.go:14)  FUNCDATA        $0, gclocals·d4dc2f11db048877dbc0f60a22b4adb3(SB)
        0x0000 00000 (/home/shansen/foo.go:14)  FUNCDATA        $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
        0x0000 00000 (/home/shansen/foo.go:14)  MOVQ    "".val+16(SP), AX
        0x0005 00005 (/home/shansen/foo.go:15)  TESTQ   AX, AX
        0x0008 00008 (/home/shansen/foo.go:15)  JNE     16
        0x000a 00010 (/home/shansen/foo.go:16)  MOVB    $1, "".~r1+24(SP)
        0x000f 00015 (/home/shansen/foo.go:16)  RET
        0x0010 00016 (/home/shansen/foo.go:18)  MOVB    $0, "".~r1+24(SP)
        0x0015 00021 (/home/shansen/foo.go:18)  RET
        0x0000 48 8b 44 24 10 48 85 c0 75 06 c6 44 24 18 01 c3  H.D$.H..u..D$...
        0x0010 c6 44 24 18 00 c3                                .D$...
"".TestLen STEXT nosplit size=22 args=0x18 locals=0x0
        0x0000 00000 (/home/shansen/foo.go:21)  TEXT    "".TestLen(SB), NOSPLIT, $0-24
        0x0000 00000 (/home/shansen/foo.go:21)  FUNCDATA        $0, gclocals·d4dc2f11db048877dbc0f60a22b4adb3(SB)
        0x0000 00000 (/home/shansen/foo.go:21)  FUNCDATA        $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
        0x0000 00000 (/home/shansen/foo.go:21)  MOVQ    "".val+16(SP), AX
        0x0005 00005 (/home/shansen/foo.go:22)  TESTQ   AX, AX
        0x0008 00008 (/home/shansen/foo.go:22)  JNE     16
        0x000a 00010 (/home/shansen/foo.go:23)  MOVB    $1, "".~r1+24(SP)
        0x000f 00015 (/home/shansen/foo.go:23)  RET
        0x0010 00016 (/home/shansen/foo.go:25)  MOVB    $0, "".~r1+24(SP)
        0x0015 00021 (/home/shansen/foo.go:25)  RET
        0x0000 48 8b 44 24 10 48 85 c0 75 06 c6 44 24 18 01 c3  H.D$.H..u..D$...
        0x0010 c6 44 24 18 00 c3                                .D$...