You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: symtab.go
    path of file: ./repos/gccrs/libgo/go/runtime
    
    the code of the file until where you have to start completion: // Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package runtime

import (
	"internal/bytealg"
	_ "unsafe" // for go:linkname
)

// Frames may be used to get function/file/line information for a
// slice of PC values returned by Callers.
type Frames struct {
	// callers is a slice of PCs that have not yet been expanded to frames.
	callers []uintptr

	// The last PC we saw.
	last uintptr

	// The number of times we've seen last.
	lastCount int
}

// Frame is the information returned by Frames for each call frame.
type Frame struct {
	// PC is the program counter for the location in this frame.
	// For a fra
    
func (ci *Frames) Next() (frame Frame, more bool) {
	if len(ci.callers) == 0 {
		return Frame{}, false
	}

	pc := ci.callers[0]
	ci.callers = ci.callers[1:]

	i := 0
	if pc == ci.last {
		ci.lastCount++
		i = ci.lastCount
	} else {
		ci.last = pc
		ci.lastCount = 0
	}
	more = len(ci.callers) > 0

	// Subtract 1 from PC to undo the 1 we added in callback in
	// go-callers.c.
	function, file, line, _ := funcfileline(pc-1, int32(i), more)
	if function == "" && file == "" {
		return Frame{}, more
	}

	// Demangle function name if needed.
	function = demangleSymbol(function)

	// Create entry.
	entry := funcentry(pc - 1)
	f := &Func{name: function, entry: entry}

	xpc := pc
	if xpc > entry {
		xpc--
	}

	frame = Frame{
		PC:       xpc,
		Func:     f,
		Function: function,
		File:     file,
		Line:     line,
		Entry:    entry,
	}

	return frame, more
}