flagMsan          = flag.Bool("msan", false, "enable MSan interface")
	flagAsan          = flag.Bool("asan", false, "enable ASan interface")
	flagAslr          = flag.Bool("aslr", true, "enable ASLR for buildmode=c-shared on windows")

	flagFieldTrack = flag.String("k", "", "set field tracking `symbol`")
	flagLibGCC     = flag.String("libgcc", "", "compiler support lib for internal linking; use \"none\" to disable")

		//       VADDR=0xffffffff80200000
		// stextOffset=0xffffffff80200198
		//       Start=0xffffffff83200000
		//       Limit=0xffffffff84200000
		//      Offset=0 (0xc000000000000000 for PowerPC64) (== Start for ASLR kernel)
		// So the base should be:
		if stextOffset != nil && (start%pageSize) == (*stextOffset%pageSize) {
			// perf uses the address of _stext as start. Some tools may

func (m *Matcher) stack(w Writer) bool {
	const maxStack = 16
	var stk [maxStack]uintptr
	n := runtime.Callers(2, stk[:])
	// caller #2 is not for printing; need it to normalize PCs if ASLR.
	if n <= 1 {
		return false
	}

	base := stk[0]
	// normalize PCs
	for i := range stk[:n] {
		stk[i] -= base
	}

	h := Hash(stk[:n])
	if m.ShouldPrint(h) {
		var d *dedup