linker

type ArHdr struct {
	Name [16]byte
	Date [12]byte
	Uid  [6]byte
	Gid  [6]byte
	Mode [8]byte
	Size [10]byte // 保存一个section中数据区域的大小
	Fmag [2]byte
}

type Context struct {
	Args ContextArgs
	Objs []*ObjFile
}

type ContextArgs struct {
	Output       string      // 保存链接器最后生成的文件名字
	Emulation    MachineType // 哪种架构
	LibraryPaths []string    // 库文件的路径，这是个数组
}

type EHdr struct {
	Ident     [16]uint8
	Type      uint16
	Machine   uint16
	Version   uint32
	Entry     uint64
	PhOff     uint64
	ShOff     uint64
	Flags     uint32
	EhSize    uint16
	PhEntSize uint16
	PhNum     uint16
	ShEntSize uint16
	ShNum     uint16
	ShStrNdx  uint16
}

type File struct {
	Filename string
	Contents []byte
	Parent   *File
}

type FileType uint16

type InputFile struct {
	File         *File
	ElfSections  []SHdr // section数组
	ShStrtab     []byte // 对象文件的strtab sh
	FirstGlobal  int64
	ElfSyms      []Sym  // 符号表数组
	SymbolStrtab []byte // 符号表的str table
}

type MachineType = uint8

type MachineTypeStringer struct {
	MachineType
}

type ObjFile struct {
	InputFile       // 结构体组合
	SymtabSec *SHdr // `symbol table`这个sh包含了所有sh的类型信息
}

type SHdr struct {
	Name      uint32 // 这个name是指再shstrtab这个sh中，当前sh名字的v起始偏移
	Type      uint32
	Flags     uint64
	Addr      uint64
	Offset    uint64
	Size      uint64
	Link      uint32
	Info      uint32
	AddrAlign uint64
	EntSize   uint64
}

type Sym struct {
	Name  uint32
	Info  uint8
	Other uint8
	Shndx uint16
	Val   uint64
	Size  uint64
}