} else {
		return errorf("bad magic - not mach-o file")
	}

	is64 := e.Uint32(hdr[:]) == 0xFEEDFACF
	ncmd := e.Uint32(hdr[4*4:])
	cmdsz := e.Uint32(hdr[5*4:])
	if ncmd > 0x10000 || cmdsz >= 0x01000000 {
		return errorf("implausible mach-o header ncmd=%d cmdsz=%d", ncmd, cmdsz)
	}

	if is64 {
		f.MustSeek(4, 1) // skip reserved word in header
	}

	m := &ldMachoObj{
		f:          f,
		e:          e,

	if is64bit := exem.Magic == macho.Magic64; is64bit {
		// mach_header_64 has one extra uint32.
		cmdOffset += unsafe.Sizeof(exem.Magic)
	}
	dwarfCmdOffset := uint32(cmdOffset) + exem.FileHeader.Cmdsz
	availablePadding := textsect.Offset - dwarfCmdOffset
	if availablePadding < realdwarf.Len {
		return fmt.Errorf("no room to add dwarf info. Need at least %d padding bytes, found %d", realdwarf.Len, availablePadding)
	}

package macho

import "strconv"

// A FileHeader represents a Mach-O file header.
type FileHeader struct {
	Magic  uint32
	Cpu    Cpu
	SubCpu uint32
	Type   Type
	Ncmd   uint32
	Cmdsz  uint32
	Flags  uint32
}

const (
	fileHeaderSize32 = 7 * 4
	fileHeaderSize64 = 8 * 4
)

const (
	Magic32  uint32 = 0xfeedface
	Magic64  uint32 = 0xfeedfacf
	MagicFat uint32 = 0xcafebabe
)

		return nil, err
	}

	// Then load commands.
	offset := int64(fileHeaderSize32)
	if f.Magic == Magic64 {
		offset = fileHeaderSize64
	}
	dat, err := saferio.ReadDataAt(r, uint64(f.Cmdsz), offset)
	if err != nil {
		return nil, err
	}
	c := saferio.SliceCap[Load](uint64(f.Ncmd))
	if c < 0 {
		return nil, &FormatError{offset, "too many load commands", nil}
	}
	f.Loads = make([]Load, 0, c)

		{"File.Dysymtab", Field, 0},
		{"File.FileHeader", Field, 0},
		{"File.Loads", Field, 0},
		{"File.Sections", Field, 0},
		{"File.Symtab", Field, 0},
		{"FileHeader", Type, 0},
		{"FileHeader.Cmdsz", Field, 0},
		{"FileHeader.Cpu", Field, 0},
		{"FileHeader.Flags", Field, 0},
		{"FileHeader.Magic", Field, 0},
		{"FileHeader.Ncmd", Field, 0},
		{"FileHeader.SubCpu", Field, 0},

pkg debug/macho, type File struct, Symtab *Symtab
pkg debug/macho, type File struct, embedded FileHeader
pkg debug/macho, type FileHeader struct
pkg debug/macho, type FileHeader struct, Cmdsz uint32
pkg debug/macho, type FileHeader struct, Cpu Cpu
pkg debug/macho, type FileHeader struct, Flags uint32
pkg debug/macho, type FileHeader struct, Magic uint32
pkg debug/macho, type FileHeader struct, Ncmd uint32