stackOf := func(c byte) int {
		return strings.IndexByte(chars, c)
	}

	trimStack := func() {
		for i := range stack {
			stk := &stack[i]
			for len(*stk) > 0 && (*stk)[len(*stk)-1].i >= len(dst) {
				*stk = (*stk)[:len(*stk)-1]
			}
		}
	}

Src:
	for i := 0; i < len(src); i++ {
		if open, ok := src[i].(*openPlain); ok {

	b := make([]byte, 1024)
	stk := string(b[:Stack(b, false)])
	if !strings.HasPrefix(stk, "goroutine ") {
		t.Errorf("Stack (len %d):\n%s", len(stk), stk)
		t.Errorf("Stack output should begin with \"goroutine \"")
	}
}

func TestStackAllOutput(t *testing.T) {
	b := make([]byte, 1024)
	stk := string(b[:Stack(b, true)])
	if !strings.HasPrefix(stk, "goroutine ") {

		// variable/value pair to reinstate on exit
		n int32 // variable ID
		v *ssa.Value

		// Note: only one of b or n,v will be set.
	}
	var stk []stackEntry

	stk = append(stk, stackEntry{b: s.f.Entry})
	for len(stk) > 0 {
		work := stk[len(stk)-1]
		stk = stk[:len(stk)-1]

		b := work.b
		if b == nil {
			// On exit from a block, this case will undo any assignments done below.
			values[work.n] = work.v

func (e *Emitter) Stack(stk []*trace.Frame) int {
	return e.buildBranch(e.frameTree, stk)
}

// buildBranch builds one branch in the prefix tree rooted at ctx.frameTree.
func (e *Emitter) buildBranch(parent frameNode, stk []*trace.Frame) int {
	if len(stk) == 0 {
		return parent.id
	}
	last := len(stk) - 1
	frame := stk[last]
	stk = stk[:last]

	node, ok := parent.children[frame.PC]

			stk = stk[len(l.pcs):]
			continue
		}

		frames, symbolizeResult := allFrames(addr)
		if len(frames) == 0 { // runtime.goexit.
			if id := b.emitLocation(); id > 0 {
				locs = append(locs, id)
			}
			stk = stk[1:]
			continue
		}

		if added := b.deck.tryAdd(addr, frames, symbolizeResult); added {
			stk = stk[1:]
			continue
		}

			// the cycle as (for example) package p imports package q imports package r
			// imports package p.
			stk = append(stk, ptest.ImportPath)
			slices.Reverse(stk)

			return &PackageError{
				ImportStack:   stk,
				Err:           errors.New("import cycle not allowed in test"),
				IsImportCycle: true,
			}
		}
		for _, dep := range p.Internal.Imports {

	}
}

// augmentName attempts to use stk to augment the name of the goroutine
// with stack information. This stack must be related to the goroutine
// in some way, but it doesn't really matter which stack.
func (gs *gState[R]) augmentName(stk trace.Stack) {
	if gs.named {
		return
	}
	if stk == trace.NoStack {
		return
	}
	name := lastFunc(stk)
	gs.baseName += fmt.Sprintf(" %s", name)
	gs.named = true

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
		for {

		// Only racing against reader, not other writers.
		count, time := b.takeOverflow()
		if count > 0 {
			var stk [1]uintptr
			stk[0] = uintptr(count)
			b.write(nil, int64(time), nil, stk[:])
		}
	} else if hasOverflow || !b.canWriteRecord(len(stk)) {
		// Pending overflow without room to write overflow and new records
		// or no overflow but also no room for new record.
		b.incrementOverflow(now)
		b.wakeupExtra()

	}
	if p.write != nil {
		panic("pprof: Add called on built-in Profile " + p.name)
	}

	stk := make([]uintptr, 32)
	n := runtime.Callers(skip+1, stk[:])
	stk = stk[:n]
	if len(stk) == 0 {
		// The value for skip is too large, and there's no stack trace to record.
		stk = []uintptr{abi.FuncPCABIInternal(lostProfileEvent)}
	}

	p.mu.Lock()
	defer p.mu.Unlock()
	if p.m[value] != nil {