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: builder.go
    path of file: ./repos/bytom/protocol/vm/vmutil
    
    the code of the file until where you have to start completion: package vmutil

import (
	"encoding/binary"

	"github.com/bytom/bytom/errors"
	"github.com/bytom/bytom/protocol/vm"
)

type Builder struct {
	program     []byte
	jumpCounter int

	// Maps a jump target number to its absolute address.
	jumpAddr map[int]uint32

	
    
func (b *Builder) Build() ([]byte, error) {
	for target, placeholders := range b.jumpPlaceholders {
		addr, ok := b.jumpAddr[target]
		if !ok {
			return nil, errors.Wrapf(ErrUnresolvedJump, "target %d", target)
		}
		for _, placeholder := range placeholders {
			binary.LittleEndian.PutUint32(b.program[placeholder:placeholder+4], addr)
		}
	}
	return b.program, nil
}