var (
	coverageEnabled  = len(coverage()) > 0
	coverageSnapshot = make([]byte, len(coverage()))

	// _counters and _ecounters mark the start and end, respectively, of where
	// the 8-bit coverage counters reside in memory. They're known to cmd/link,
	// which specially assigns their addresses for this purpose.
	_counters, _ecounters [0]byte

		ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.__stop___sancov_cntrs", 0), sect)
		ldr.SetSymSect(ldr.LookupOrCreateSym("internal/fuzz._counters", 0), sect)
		ldr.SetSymSect(ldr.LookupOrCreateSym("internal/fuzz._ecounters", 0), sect)
	}

	// Assign runtime.end to the last section of data segment.
	ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.end", 0), Segdata.Sections[len(Segdata.Sections)-1])

				// possibility of a zero value ; see
				// runtime.addCovMeta), so subtract off 1 here to form
				// the real package ID.
				pkgId--
			}

			tcounters = rdCounters(counters, tcounters)
			if err := f(pkgId, funcId, tcounters); err != nil {
				return err
			}

			// Skip over this function.
			i += coverage.FirstCtrOffset + int(nCtrs) - 1
		}
		if s.debug {

// totally public telemetry data.
//
// There are two kinds of counters, basic counters and stack counters.
// Basic counters are created by [New].
// Stack counters are created by [NewStack].
// Both are incremented by calling Inc().
//
// Basic counters are very cheap. Stack counters are more expensive, as they
// require parsing the stack. (Stack counters are implemented as basic counters

		names[i] = s.counter.Name()
	}
	return names
}

// Counters returns the known Counters for a StackCounter.
// There may be more in the count file.
func (c *StackCounter) Counters() []*Counter {
	c.mu.Lock()
	defer c.mu.Unlock()
	counters := make([]*Counter, len(c.stacks))
	for i, s := range c.stacks {
		counters[i] = s.counter
	}
	return counters
}

func eq(a, b []uintptr) bool {
	if len(a) != len(b) {

}

type ProgramConfig struct {
	// the counter names may have to be
	// repeated for each program. (e.g., if the counters are in a package
	// that is used in more than one program.)
	Name     string
	Versions []string        // versions present in a counterconfig
	Counters []CounterConfig `json:",omitempty"`
	Stacks   []CounterConfig `json:",omitempty"`
}

type CounterConfig struct {
	Name  string

	// FIXME: in theory either A) len(val.Counters) is zero, or B)
	// the two lengths are equal. Assert if not? Of course, we could
	// see odd stuff if there is source file skew.
	if *verbflag > 4 {
		fmt.Printf("visit pk=%d fid=%d len(counters)=%d\n", data.PkgIdx, data.FuncIdx, len(data.Counters))
	}
	if len(val.Counters) < len(data.Counters) {
		t := val.Counters
		val.Counters = mm.AllocateCounters(len(data.Counters))

func Expand(counter string) []string {
	prefix, rest, hasBuckets := strings.Cut(counter, "{")
	var counters []string
	if hasBuckets {
		buckets := strings.Split(strings.TrimSuffix(rest, "}"), ",")
		for _, b := range buckets {
			counters = append(counters, prefix+b)
		}
	} else {
		counters = append(counters, prefix)
	}
	return counters

			if prev, found := pmm[key]; found {
				// Note: no overflow reporting here.
				if err, _ := ts.cm.MergeCounters(data.Counters, prev); err != nil {
					return fmt.Errorf("processing counter data file %s: %v", cdf, err)
				}
			}
			c := ts.AllocateCounters(len(data.Counters))
			copy(c, data.Counters)
			pmm[key] = c
		}
		return nil
	}

	// Read counter data files.
	for _, cdf := range p.CounterDataFiles {

func ReadStackCounter(c *counter.StackCounter) (stackCounts map[string]uint64, _ error) {
	return ic.ReadStack(c)
}

// ReadFile reads the counters and stack counters from the given file.
func ReadFile(name string) (counters, stackCounters map[string]uint64, _ error) {
	return ic.ReadFile(name)