/*
* Copyright (c) 1999-2010 Apple Inc.  All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#ifndef _MACHO64SPEC_H_INCLUDED_
#define _MACHO64SPEC_H_INCLUDED_

#ifdef _WIN32
	#include <inttypes.h>
#else
	#include <stdint.h>
#endif

typedef int integer_t;
typedef integer_t	cpu_type_t;
typedef integer_t	cpu_subtype_t;
typedef integer_t	cpu_threadtype_t;

#define CPU_STATE_MAX		4
#define CPU_STATE_USER		0
#define CPU_STATE_SYSTEM	1
#define CPU_STATE_IDLE		2
#define CPU_STATE_NICE		3

/*
* Capability bits used in the definition of cpu_type.
*/
#define	CPU_ARCH_MASK	0xff000000		/* mask for architecture bits */
#define CPU_ARCH_ABI64	0x01000000		/* 64 bit ABI */

/*
*	Machine types known by all.
*/

#define CPU_TYPE_ANY		((cpu_type_t) -1)

#define CPU_TYPE_VAX		((cpu_type_t) 1)
/* skip				((cpu_type_t) 2)	*/
/* skip				((cpu_type_t) 3)	*/
/* skip				((cpu_type_t) 4)	*/
/* skip				((cpu_type_t) 5)	*/
#define	CPU_TYPE_MC680x0	((cpu_type_t) 6)
#define CPU_TYPE_X86		((cpu_type_t) 7)
#define CPU_TYPE_I386		CPU_TYPE_X86		/* compatibility */
#define	CPU_TYPE_X86_64		(CPU_TYPE_X86 | CPU_ARCH_ABI64)

/* skip CPU_TYPE_MIPS		((cpu_type_t) 8)	*/
/* skip 			((cpu_type_t) 9)	*/
#define CPU_TYPE_MC98000	((cpu_type_t) 10)
#define CPU_TYPE_HPPA           ((cpu_type_t) 11)
#define CPU_TYPE_ARM		((cpu_type_t) 12)
#define CPU_TYPE_ARM64          (CPU_TYPE_ARM | CPU_ARCH_ABI64)
#define CPU_TYPE_MC88000	((cpu_type_t) 13)
#define CPU_TYPE_SPARC		((cpu_type_t) 14)
#define CPU_TYPE_I860		((cpu_type_t) 15)
/* skip	CPU_TYPE_ALPHA		((cpu_type_t) 16)	*/
/* skip				((cpu_type_t) 17)	*/
#define CPU_TYPE_POWERPC		((cpu_type_t) 18)
#define CPU_TYPE_POWERPC64		(CPU_TYPE_POWERPC | CPU_ARCH_ABI64)

/*
*	Machine subtypes (these are defined here, instead of in a machine
*	dependent directory, so that any program can get all definitions
*	regardless of where is it compiled).
*/

/*
* Capability bits used in the definition of cpu_subtype.
*/
#define CPU_SUBTYPE_MASK	0xff000000	/* mask for feature flags */
#define CPU_SUBTYPE_LIB64	0x80000000	/* 64 bit libraries */


/*
*	Object files that are hand-crafted to run on any
*	implementation of an architecture are tagged with
*	CPU_SUBTYPE_MULTIPLE.  This functions essentially the same as
*	the "ALL" subtype of an architecture except that it allows us
*	to easily find object files that may need to be modified
*	whenever a new implementation of an architecture comes out.
*
*	It is the responsibility of the implementor to make sure the
*	software handles unsupported implementations elegantly.
*/
#define	CPU_SUBTYPE_MULTIPLE		((cpu_subtype_t) -1)
#define CPU_SUBTYPE_LITTLE_ENDIAN	((cpu_subtype_t) 0)
#define CPU_SUBTYPE_BIG_ENDIAN		((cpu_subtype_t) 1)

/*
*     Machine threadtypes.
*     This is none - not defined - for most machine types/subtypes.
*/
#define CPU_THREADTYPE_NONE		((cpu_threadtype_t) 0)

/*
*	VAX subtypes (these do *not* necessary conform to the actual cpu
*	ID assigned by DEC available via the SID register).
*/

#define	CPU_SUBTYPE_VAX_ALL	((cpu_subtype_t) 0) 
#define CPU_SUBTYPE_VAX780	((cpu_subtype_t) 1)
#define CPU_SUBTYPE_VAX785	((cpu_subtype_t) 2)
#define CPU_SUBTYPE_VAX750	((cpu_subtype_t) 3)
#define CPU_SUBTYPE_VAX730	((cpu_subtype_t) 4)
#define CPU_SUBTYPE_UVAXI	((cpu_subtype_t) 5)
#define CPU_SUBTYPE_UVAXII	((cpu_subtype_t) 6)
#define CPU_SUBTYPE_VAX8200	((cpu_subtype_t) 7)
#define CPU_SUBTYPE_VAX8500	((cpu_subtype_t) 8)
#define CPU_SUBTYPE_VAX8600	((cpu_subtype_t) 9)
#define CPU_SUBTYPE_VAX8650	((cpu_subtype_t) 10)
#define CPU_SUBTYPE_VAX8800	((cpu_subtype_t) 11)
#define CPU_SUBTYPE_UVAXIII	((cpu_subtype_t) 12)

/*
* 	680x0 subtypes
*
* The subtype definitions here are unusual for historical reasons.
* NeXT used to consider 68030 code as generic 68000 code.  For
* backwards compatability:
*
*	CPU_SUBTYPE_MC68030 symbol has been preserved for source code
*	compatability.
*
*	CPU_SUBTYPE_MC680x0_ALL has been defined to be the same
*	subtype as CPU_SUBTYPE_MC68030 for binary comatability.
*
*	CPU_SUBTYPE_MC68030_ONLY has been added to allow new object
*	files to be tagged as containing 68030-specific instructions.
*/

#define	CPU_SUBTYPE_MC680x0_ALL		((cpu_subtype_t) 1)
#define CPU_SUBTYPE_MC68030		((cpu_subtype_t) 1) /* compat */
#define CPU_SUBTYPE_MC68040		((cpu_subtype_t) 2) 
#define	CPU_SUBTYPE_MC68030_ONLY	((cpu_subtype_t) 3)

/*
*	I386 subtypes
*/

#define CPU_SUBTYPE_INTEL(f, m)	((cpu_subtype_t) (f) + ((m) << 4))

#define	CPU_SUBTYPE_I386_ALL			CPU_SUBTYPE_INTEL(3, 0)
#define CPU_SUBTYPE_386					CPU_SUBTYPE_INTEL(3, 0)
#define CPU_SUBTYPE_486					CPU_SUBTYPE_INTEL(4, 0)
#define CPU_SUBTYPE_486SX				CPU_SUBTYPE_INTEL(4, 8)	// 8 << 4 = 128
#define CPU_SUBTYPE_586					CPU_SUBTYPE_INTEL(5, 0)
#define CPU_SUBTYPE_PENT	CPU_SUBTYPE_INTEL(5, 0)
#define CPU_SUBTYPE_PENTPRO	CPU_SUBTYPE_INTEL(6, 1)
#define CPU_SUBTYPE_PENTII_M3	CPU_SUBTYPE_INTEL(6, 3)
#define CPU_SUBTYPE_PENTII_M5	CPU_SUBTYPE_INTEL(6, 5)
#define CPU_SUBTYPE_CELERON				CPU_SUBTYPE_INTEL(7, 6)
#define CPU_SUBTYPE_CELERON_MOBILE		CPU_SUBTYPE_INTEL(7, 7)
#define CPU_SUBTYPE_PENTIUM_3			CPU_SUBTYPE_INTEL(8, 0)
#define CPU_SUBTYPE_PENTIUM_3_M			CPU_SUBTYPE_INTEL(8, 1)
#define CPU_SUBTYPE_PENTIUM_3_XEON		CPU_SUBTYPE_INTEL(8, 2)
#define CPU_SUBTYPE_PENTIUM_M			CPU_SUBTYPE_INTEL(9, 0)
#define CPU_SUBTYPE_PENTIUM_4			CPU_SUBTYPE_INTEL(10, 0)
#define CPU_SUBTYPE_PENTIUM_4_M			CPU_SUBTYPE_INTEL(10, 1)
#define CPU_SUBTYPE_ITANIUM				CPU_SUBTYPE_INTEL(11, 0)
#define CPU_SUBTYPE_ITANIUM_2			CPU_SUBTYPE_INTEL(11, 1)
#define CPU_SUBTYPE_XEON				CPU_SUBTYPE_INTEL(12, 0)
#define CPU_SUBTYPE_XEON_MP				CPU_SUBTYPE_INTEL(12, 1)

#define CPU_SUBTYPE_INTEL_FAMILY(x)	((x) & 15)
#define CPU_SUBTYPE_INTEL_FAMILY_MAX	15

#define CPU_SUBTYPE_INTEL_MODEL(x)	((x) >> 4)
#define CPU_SUBTYPE_INTEL_MODEL_ALL	0

/*
*	X86 subtypes.
*/

#define CPU_SUBTYPE_X86_ALL		((cpu_subtype_t)3)
#define CPU_SUBTYPE_X86_64_ALL		((cpu_subtype_t)3)
#define CPU_SUBTYPE_X86_ARCH1		((cpu_subtype_t)4)
#define CPU_SUBTYPE_X86_64_H		((cpu_subtype_t)8)	/* Haswell feature subset */


#define CPU_THREADTYPE_INTEL_HTT	((cpu_threadtype_t) 1)

/*
*	Mips subtypes.
*/

#define	CPU_SUBTYPE_MIPS_ALL	((cpu_subtype_t) 0)
#define CPU_SUBTYPE_MIPS_R2300	((cpu_subtype_t) 1)
#define CPU_SUBTYPE_MIPS_R2600	((cpu_subtype_t) 2)
#define CPU_SUBTYPE_MIPS_R2800	((cpu_subtype_t) 3)
#define CPU_SUBTYPE_MIPS_R2000a	((cpu_subtype_t) 4)	/* pmax */
#define CPU_SUBTYPE_MIPS_R2000	((cpu_subtype_t) 5)
#define CPU_SUBTYPE_MIPS_R3000a	((cpu_subtype_t) 6)	/* 3max */
#define CPU_SUBTYPE_MIPS_R3000	((cpu_subtype_t) 7)

/*
*	MC98000 (PowerPC) subtypes
*/
#define	CPU_SUBTYPE_MC98000_ALL	((cpu_subtype_t) 0)
#define CPU_SUBTYPE_MC98601	((cpu_subtype_t) 1)

/*
*	HPPA subtypes for Hewlett-Packard HP-PA family of
*	risc processors. Port by NeXT to 700 series.
*/

#define	CPU_SUBTYPE_HPPA_ALL		((cpu_subtype_t) 0)
#define CPU_SUBTYPE_HPPA_7100		((cpu_subtype_t) 0) /* compat */
#define CPU_SUBTYPE_HPPA_7100LC		((cpu_subtype_t) 1)

/*
*	MC88000 subtypes.
*/
#define	CPU_SUBTYPE_MC88000_ALL	((cpu_subtype_t) 0)
#define CPU_SUBTYPE_MC88100	((cpu_subtype_t) 1)
#define CPU_SUBTYPE_MC88110	((cpu_subtype_t) 2)

/*
*	SPARC subtypes
*/
#define	CPU_SUBTYPE_SPARC_ALL		((cpu_subtype_t) 0)

/*
*	I860 subtypes
*/
#define CPU_SUBTYPE_I860_ALL	((cpu_subtype_t) 0)
#define CPU_SUBTYPE_I860_860	((cpu_subtype_t) 1)

/*
*	PowerPC subtypes
*/
#define CPU_SUBTYPE_POWERPC_ALL		((cpu_subtype_t) 0)
#define CPU_SUBTYPE_POWERPC_601		((cpu_subtype_t) 1)
#define CPU_SUBTYPE_POWERPC_602		((cpu_subtype_t) 2)
#define CPU_SUBTYPE_POWERPC_603		((cpu_subtype_t) 3)
#define CPU_SUBTYPE_POWERPC_603e	((cpu_subtype_t) 4)
#define CPU_SUBTYPE_POWERPC_603ev	((cpu_subtype_t) 5)
#define CPU_SUBTYPE_POWERPC_604		((cpu_subtype_t) 6)
#define CPU_SUBTYPE_POWERPC_604e	((cpu_subtype_t) 7)
#define CPU_SUBTYPE_POWERPC_620		((cpu_subtype_t) 8)
#define CPU_SUBTYPE_POWERPC_750		((cpu_subtype_t) 9)
#define CPU_SUBTYPE_POWERPC_7400	((cpu_subtype_t) 10)
#define CPU_SUBTYPE_POWERPC_7450	((cpu_subtype_t) 11)
#define CPU_SUBTYPE_POWERPC_970		((cpu_subtype_t) 100)

/*
*	ARM subtypes
*/
#define CPU_SUBTYPE_ARM_ALL             ((cpu_subtype_t) 0)
#define CPU_SUBTYPE_ARM_V4T             ((cpu_subtype_t) 5)
#define CPU_SUBTYPE_ARM_V6              ((cpu_subtype_t) 6)
#define CPU_SUBTYPE_ARM_V5TEJ           ((cpu_subtype_t) 7)
#define CPU_SUBTYPE_ARM_XSCALE		((cpu_subtype_t) 8)
#define CPU_SUBTYPE_ARM_V7		((cpu_subtype_t) 9)
#define CPU_SUBTYPE_ARM_V7F		((cpu_subtype_t) 10) /* Cortex A9 */
#define CPU_SUBTYPE_ARM_V7S		((cpu_subtype_t) 11) /* Swift */
#define CPU_SUBTYPE_ARM_V7K		((cpu_subtype_t) 12)
#define CPU_SUBTYPE_ARM_V6M		((cpu_subtype_t) 14) /* Not meant to be run under xnu */
#define CPU_SUBTYPE_ARM_V7M		((cpu_subtype_t) 15) /* Not meant to be run under xnu */
#define CPU_SUBTYPE_ARM_V7EM		((cpu_subtype_t) 16) /* Not meant to be run under xnu */

#define CPU_SUBTYPE_ARM_V8		((cpu_subtype_t) 13)

/*
*  ARM64 subtypes
*/
#define CPU_SUBTYPE_ARM64_ALL           ((cpu_subtype_t) 0)
#define CPU_SUBTYPE_ARM64_V8            ((cpu_subtype_t) 1)

/*
*	CPU families (sysctl hw.cpufamily)
*
* These are meant to identify the CPU's marketing name - an
* application can map these to (possibly) localized strings.
* NB: the encodings of the CPU families are intentionally arbitrary.
* There is no ordering, and you should never try to deduce whether
* or not some feature is available based on the family.
* Use feature flags (eg, hw.optional.altivec) to test for optional
* functionality.
*/
#define CPUFAMILY_UNKNOWN   		0
#define CPUFAMILY_POWERPC_G3		0xcee41549
#define CPUFAMILY_POWERPC_G4		0x77c184ae
#define CPUFAMILY_POWERPC_G5		0xed76d8aa
#define CPUFAMILY_INTEL_6_13		0xaa33392b
#define CPUFAMILY_INTEL_PENRYN		0x78ea4fbc
#define CPUFAMILY_INTEL_NEHALEM		0x6b5a4cd2
#define CPUFAMILY_INTEL_WESTMERE	0x573b5eec
#define CPUFAMILY_INTEL_SANDYBRIDGE	0x5490b78c
#define CPUFAMILY_INTEL_IVYBRIDGE	0x1f65e835
#define CPUFAMILY_INTEL_HASWELL		0x10b282dc
#define CPUFAMILY_INTEL_BROADWELL	0x582ed09c
#define CPUFAMILY_INTEL_SKYLAKE		0x37fc219f
#define CPUFAMILY_ARM_9			0xe73283ae
#define CPUFAMILY_ARM_11		0x8ff620d8
#define CPUFAMILY_ARM_XSCALE		0x53b005f5
#define CPUFAMILY_ARM_12                0xbd1b0ae9
#define CPUFAMILY_ARM_13		0x0cc90e64
#define CPUFAMILY_ARM_14		0x96077ef1
#define CPUFAMILY_ARM_15		0xa8511bca
#define CPUFAMILY_ARM_SWIFT 		0x1e2d6381
#define CPUFAMILY_ARM_CYCLONE		0x37a09642
#define CPUFAMILY_ARM_TYPHOON		0x2c91a47e
#define CPUFAMILY_ARM_TWISTER		0x92fb37c8
#define CPUFAMILY_ARM_HURRICANE		0x67ceee93

/* The following synonyms are deprecated: */
#define CPUFAMILY_INTEL_6_23	CPUFAMILY_INTEL_PENRYN
#define CPUFAMILY_INTEL_6_26	CPUFAMILY_INTEL_NEHALEM

/*
*	Types defined:
*
*	vm_prot_t		VM protection values.
*/

typedef int		vm_prot_t;

/*
*	Protection values, defined as bits within the vm_prot_t type
*/

#define	VM_PROT_NONE	((vm_prot_t) 0x00)

#define VM_PROT_READ	((vm_prot_t) 0x01)	/* read permission */
#define VM_PROT_WRITE	((vm_prot_t) 0x02)	/* write permission */
#define VM_PROT_EXECUTE	((vm_prot_t) 0x04)	/* execute permission */

/*
*	The default protection for newly-created virtual memory
*/

#define VM_PROT_DEFAULT	(VM_PROT_READ|VM_PROT_WRITE)

/*
*	The maximum privileges possible, for parameter checking.
*/

#define VM_PROT_ALL	(VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)

/*
*	An invalid protection value.
*	Used only by memory_object_lock_request to indicate no change
*	to page locks.  Using -1 here is a bad idea because it
*	looks like VM_PROT_ALL and then some.
*/

#define VM_PROT_NO_CHANGE	((vm_prot_t) 0x08)

/*
*      When a caller finds that he cannot obtain write permission on a
*      mapped entry, the following flag can be used.  The entry will
*      be made "needs copy" effectively copying the object (using COW),
*      and write permission will be added to the maximum protections
*      for the associated entry.
*/

#define VM_PROT_COPY            ((vm_prot_t) 0x10)


/*
*	Another invalid protection value.
*	Used only by memory_object_data_request upon an object
*	which has specified a copy_call copy strategy. It is used
*	when the kernel wants a page belonging to a copy of the
*	object, and is only asking the object as a result of
*	following a shadow chain. This solves the race between pages
*	being pushed up by the memory manager and the kernel
*	walking down the shadow chain.
*/

#define VM_PROT_WANTS_COPY	((vm_prot_t) 0x10)


/*
* 	Another invalid protection value.
*	Indicates that the other protection bits are to be applied as a mask
*	against the actual protection bits of the map entry.
*/
#define VM_PROT_IS_MASK		((vm_prot_t) 0x40)

/*
* Another invalid protection value to support execute-only protection.
* VM_PROT_STRIP_READ is a special marker that tells mprotect to not
* set VM_PROT_READ. We have to do it this way because existing code
* expects the system to set VM_PROT_READ if VM_PROT_EXECUTE is set.
* VM_PROT_EXECUTE_ONLY is just a convenience value to indicate that
* the memory should be executable and explicitly not readable. It will
* be ignored on platforms that do not support this type of protection.
*/
#define VM_PROT_STRIP_READ		((vm_prot_t) 0x80)
#define VM_PROT_EXECUTE_ONLY	(VM_PROT_EXECUTE|VM_PROT_STRIP_READ)

#define VM_PROT_MEMORY_TAG_MASK		0xFF000000
#define VM_PROT_MEMORY_TAG_SHIFT	24
#define VM_PROT_MEMORY_TAG(x)		(((x) >> VM_PROT_MEMORY_TAG_SHIFT) & 0xFF)
#define VM_PROT_MEMORY_TAG_MAKE(x)	(((x) & 0xFF) << VM_PROT_MEMORY_TAG_SHIFT)

/* -------------------------------------------------------------------------------------------------------------------------
* Here begins the official MACHO64 definitions
*
*
*
*
*
 ------------------------------------------------------------------------------------------------------------------------- */

/* The 32-bit mach header appears at the very beginning of the object file for
* 32-bit architectures.
*/
struct mach_header {
	uint32_t	magic;		/* mach magic number identifier */
	cpu_type_t	cputype;	/* cpu specifier */
	cpu_subtype_t	cpusubtype;	/* machine specifier */
	uint32_t	filetype;	/* type of file */
	uint32_t	ncmds;		/* number of load commands */
	uint32_t	sizeofcmds;	/* the size of all the load commands */
	uint32_t	flags;		/* flags */
};

/* Constant for the magic field of the mach_header (32-bit architectures) */
#define	MH_MAGIC	0xfeedface	/* the mach magic number */
#define MH_CIGAM	0xcefaedfe	/* NXSwapInt(MH_MAGIC) */

/*
* The 64-bit mach header appears at the very beginning of object files for
* 64-bit architectures.
*/
struct mach_header_64 {
	uint32_t	magic;		/* mach magic number identifier */
	cpu_type_t	cputype;	/* cpu specifier */
	cpu_subtype_t	cpusubtype;	/* machine specifier */
	uint32_t	filetype;	/* type of file */
	uint32_t	ncmds;		/* number of load commands */
	uint32_t	sizeofcmds;	/* the size of all the load commands */
	uint32_t	flags;		/* flags */
	uint32_t	reserved;	/* reserved */
};

/* Constant for the magic field of the mach_header_64 (64-bit architectures) */
#define MH_MAGIC_64 0xfeedfacf /* the 64-bit mach magic number */
#define MH_CIGAM_64 0xcffaedfe /* NXSwapInt(MH_MAGIC_64) */

/*
* The layout of the file depends on the filetype.  For all but the MH_OBJECT
* file type the segments are padded out and aligned on a segment alignment
* boundary for efficient demand pageing.  The MH_EXECUTE, MH_FVMLIB, MH_DYLIB,
* MH_DYLINKER and MH_BUNDLE file types also have the headers included as part
* of their first segment.
*
* The file type MH_OBJECT is a compact format intended as output of the
* assembler and input (and possibly output) of the link editor (the .o
* format).  All sections are in one unnamed segment with no segment padding.
* This format is used as an executable format when the file is so small the
* segment padding greatly increases its size.
*
* The file type MH_PRELOAD is an executable format intended for things that
* are not executed under the kernel (proms, stand alones, kernels, etc).  The
* format can be executed under the kernel but may demand paged it and not
* preload it before execution.
*
* A core file is in MH_CORE format and can be any in an arbritray legal
* Mach-O file.
*
* Constants for the filetype field of the mach_header
*/
#define	MH_OBJECT	0x1		/* relocatable object file */
#define	MH_EXECUTE	0x2		/* demand paged executable file */
#define	MH_FVMLIB	0x3		/* fixed VM shared library file */
#define	MH_CORE		0x4		/* core file */
#define	MH_PRELOAD	0x5		/* preloaded executable file */
#define	MH_DYLIB	0x6		/* dynamically bound shared library */
#define	MH_DYLINKER	0x7		/* dynamic link editor */
#define	MH_BUNDLE	0x8		/* dynamically bound bundle file */
#define	MH_DYLIB_STUB	0x9		/* shared library stub for static */
/*  linking only, no section contents */
#define	MH_DSYM		0xa		/* companion file with only debug */
/*  sections */
#define	MH_KEXT_BUNDLE	0xb		/* x86_64 kexts */

/* Constants for the flags field of the mach_header */
#define	MH_NOUNDEFS	0x1		/* the object file has no undefined
references */
#define	MH_INCRLINK	0x2		/* the object file is the output of an
incremental link against a base file
and can't be link edited again */
#define MH_DYLDLINK	0x4		/* the object file is input for the
dynamic linker and can't be staticly
link edited again */
#define MH_BINDATLOAD	0x8		/* the object file's undefined
references are bound by the dynamic
linker when loaded. */
#define MH_PREBOUND	0x10		/* the file has its dynamic undefined
references prebound. */
#define MH_SPLIT_SEGS	0x20		/* the file has its read-only and
read-write segments split */
#define MH_LAZY_INIT	0x40		/* the shared library init routine is
to be run lazily via catching memory
faults to its writeable segments
(obsolete) */
#define MH_TWOLEVEL	0x80		/* the image is using two-level name
space bindings */
#define MH_FORCE_FLAT	0x100		/* the executable is forcing all images
to use flat name space bindings */
#define MH_NOMULTIDEFS	0x200		/* this umbrella guarantees no multiple
defintions of symbols in its
sub-images so the two-level namespace
hints can always be used. */
#define MH_NOFIXPREBINDING 0x400	/* do not have dyld notify the
prebinding agent about this
executable */
#define MH_PREBINDABLE  0x800           /* the binary is not prebound but can
have its prebinding redone. only used
when MH_PREBOUND is not set. */
#define MH_ALLMODSBOUND 0x1000		/* indicates that this binary binds to
all two-level namespace modules of
its dependent libraries. only used
when MH_PREBINDABLE and MH_TWOLEVEL
are both set. */
#define MH_SUBSECTIONS_VIA_SYMBOLS 0x2000/* safe to divide up the sections into
sub-sections via symbols for dead
code stripping */
#define MH_CANONICAL    0x4000		/* the binary has been canonicalized
via the unprebind operation */
#define MH_WEAK_DEFINES	0x8000		/* the final linked image contains
external weak symbols */
#define MH_BINDS_TO_WEAK 0x10000	/* the final linked image uses
weak symbols */

#define MH_ALLOW_STACK_EXECUTION 0x20000/* When this bit is set, all stacks 
in the task will be given stack
execution privilege.  Only used in
MH_EXECUTE filetypes. */
#define MH_ROOT_SAFE 0x40000           /* When this bit is set, the binary 
declares it is safe for use in
processes with uid zero */

#define MH_SETUID_SAFE 0x80000         /* When this bit is set, the binary 
declares it is safe for use in
processes when issetugid() is true */

#define MH_NO_REEXPORTED_DYLIBS 0x100000 /* When this bit is set on a dylib, 
the static linker does not need to
examine dependent dylibs to see
if any are re-exported */
#define	MH_PIE 0x200000			/* When this bit is set, the OS will
load the main executable at a
random address.  Only used in
MH_EXECUTE filetypes. */
#define	MH_DEAD_STRIPPABLE_DYLIB 0x400000 /* Only for use on dylibs.  When
linking against a dylib that
has this bit set, the static linker
will automatically not create a
LC_LOAD_DYLIB load command to the
dylib if no symbols are being
referenced from the dylib. */
#define MH_HAS_TLV_DESCRIPTORS 0x800000 /* Contains a section of type 
S_THREAD_LOCAL_VARIABLES */

#define MH_NO_HEAP_EXECUTION 0x1000000	/* When this bit is set, the OS will
run the main executable with
a non-executable heap even on
platforms (e.g. i386) that don't
require it. Only used in MH_EXECUTE
filetypes. */

#define MH_APP_EXTENSION_SAFE 0x02000000 /* The code was linked for use in an application extension. */

/*
* The load commands directly follow the mach_header.  The total size of all
* of the commands is given by the sizeofcmds field in the mach_header.  All
* load commands must have as their first two fields cmd and cmdsize.  The cmd
* field is filled in with a constant for that command type.  Each command type
* has a structure specifically for it.  The cmdsize field is the size in bytes
* of the particular load command structure plus anything that follows it that
* is a part of the load command (i.e. section structures, strings, etc.).  To
* advance to the next load command the cmdsize can be added to the offset or
* pointer of the current load command.  The cmdsize for 32-bit architectures
* MUST be a multiple of 4 bytes and for 64-bit architectures MUST be a multiple
* of 8 bytes (these are forever the maximum alignment of any load commands).
* The padded bytes must be zero.  All tables in the object file must also
* follow these rules so the file can be memory mapped.  Otherwise the pointers
* to these tables will not work well or at all on some machines.  With all
* padding zeroed like objects will compare byte for byte.
*/
struct load_command {
	uint32_t cmd;		/* type of load command */
	uint32_t cmdsize;	/* total size of command in bytes */
};

/*
* After MacOS X 10.1 when a new load command is added that is required to be
* understood by the dynamic linker for the image to execute properly the
* LC_REQ_DYLD bit will be or'ed into the load command constant.  If the dynamic
* linker sees such a load command it it does not understand will issue a
* "unknown load command required for execution" error and refuse to use the
* image.  Other load commands without this bit that are not understood will
* simply be ignored.
*/
#define LC_REQ_DYLD 0x80000000

/* Constants for the cmd field of all load commands, the type */
#define	LC_SEGMENT	0x1	/* segment of this file to be mapped */
#define	LC_SYMTAB	0x2	/* link-edit stab symbol table info */
#define	LC_SYMSEG	0x3	/* link-edit gdb symbol table info (obsolete) */
#define	LC_THREAD	0x4	/* thread */
#define	LC_UNIXTHREAD	0x5	/* unix thread (includes a stack) */
#define	LC_LOADFVMLIB	0x6	/* load a specified fixed VM shared library */
#define	LC_IDFVMLIB	0x7	/* fixed VM shared library identification */
#define	LC_IDENT	0x8	/* object identification info (obsolete) */
#define LC_FVMFILE	0x9	/* fixed VM file inclusion (internal use) */
#define LC_PREPAGE      0xa     /* prepage command (internal use) */
#define	LC_DYSYMTAB	0xb	/* dynamic link-edit symbol table info */
#define	LC_LOAD_DYLIB	0xc	/* load a dynamically linked shared library */
#define	LC_ID_DYLIB	0xd	/* dynamically linked shared lib ident */
#define LC_LOAD_DYLINKER 0xe	/* load a dynamic linker */
#define LC_ID_DYLINKER	0xf	/* dynamic linker identification */
#define	LC_PREBOUND_DYLIB 0x10	/* modules prebound for a dynamically */
/*  linked shared library */
#define	LC_ROUTINES	0x11	/* image routines */
#define	LC_SUB_FRAMEWORK 0x12	/* sub framework */
#define	LC_SUB_UMBRELLA 0x13	/* sub umbrella */
#define	LC_SUB_CLIENT	0x14	/* sub client */
#define	LC_SUB_LIBRARY  0x15	/* sub library */
#define	LC_TWOLEVEL_HINTS 0x16	/* two-level namespace lookup hints */
#define	LC_PREBIND_CKSUM  0x17	/* prebind checksum */

/*
* load a dynamically linked shared library that is allowed to be missing
* (all symbols are weak imported).
*/
#define	LC_LOAD_WEAK_DYLIB (0x18 | LC_REQ_DYLD)

#define	LC_SEGMENT_64	0x19	/* 64-bit segment of this file to be mapped */
#define	LC_ROUTINES_64	0x1a	/* 64-bit image routines */
#define LC_UUID		0x1b	/* the uuid */
#define LC_RPATH       (0x1c | LC_REQ_DYLD)    /* runpath additions */
#define LC_CODE_SIGNATURE 0x1d	/* local of code signature */
#define LC_SEGMENT_SPLIT_INFO 0x1e /* local of info to split segments */
#define LC_REEXPORT_DYLIB (0x1f | LC_REQ_DYLD) /* load and re-export dylib */
#define	LC_LAZY_LOAD_DYLIB 0x20	/* delay load of dylib until first use */
#define	LC_ENCRYPTION_INFO 0x21	/* encrypted segment information */
#define	LC_DYLD_INFO 	0x22	/* compressed dyld information */
#define	LC_DYLD_INFO_ONLY (0x22|LC_REQ_DYLD)	/* compressed dyld information only */
#define	LC_LOAD_UPWARD_DYLIB (0x23 | LC_REQ_DYLD) /* load upward dylib */
#define LC_VERSION_MIN_MACOSX 0x24   /* build for MacOSX min OS version */
#define LC_VERSION_MIN_IPHONEOS 0x25 /* build for iPhoneOS min OS version */
#define LC_FUNCTION_STARTS 0x26 /* compressed table of function start addresses */
#define LC_DYLD_ENVIRONMENT 0x27 /* string for dyld to treat
like environment variable */
#define LC_MAIN (0x28|LC_REQ_DYLD) /* replacement for LC_UNIXTHREAD */
#define LC_DATA_IN_CODE 0x29 /* table of non-instructions in __text */
#define LC_SOURCE_VERSION 0x2A /* source version used to build binary */
#define LC_DYLIB_CODE_SIGN_DRS 0x2B /* Code signing DRs copied from linked dylibs */
#define	LC_ENCRYPTION_INFO_64 0x2C /* 64-bit encrypted segment information */
#define LC_LINKER_OPTION 0x2D /* linker options in MH_OBJECT files */
#define LC_LINKER_OPTIMIZATION_HINT 0x2E /* optimization hints in MH_OBJECT files */
#define LC_VERSION_MIN_TVOS 0x2F /* build for AppleTV min OS version */
#define LC_VERSION_MIN_WATCHOS 0x30 /* build for Watch min OS version */

/*
* A variable length string in a load command is represented by an lc_str
* union.  The strings are stored just after the load command structure and
* the offset is from the start of the load command structure.  The size
* of the string is reflected in the cmdsize field of the load command.
* Once again any padded bytes to bring the cmdsize field to a multiple
* of 4 bytes must be zero.
*/
union lc_str {
	uint32_t	offset;	/* offset to the string */
#ifndef __LP64__
	char		*ptr;	/* pointer to the string */
#endif 
};

/*
* The segment load command indicates that a part of this file is to be
* mapped into the task's address space.  The size of this segment in memory,
* vmsize, maybe equal to or larger than the amount to map from this file,
* filesize.  The file is mapped starting at fileoff to the beginning of
* the segment in memory, vmaddr.  The rest of the memory of the segment,
* if any, is allocated zero fill on demand.  The segment's maximum virtual
* memory protection and initial virtual memory protection are specified
* by the maxprot and initprot fields.  If the segment has sections then the
* section structures directly follow the segment command and their size is
* reflected in cmdsize.
*/
struct segment_command { /* for 32-bit architectures */
	uint32_t	cmd;		/* LC_SEGMENT */
	uint32_t	cmdsize;	/* includes sizeof section structs */
	char		segname[16];	/* segment name */
	uint32_t	vmaddr;		/* memory address of this segment */
	uint32_t	vmsize;		/* memory size of this segment */
	uint32_t	fileoff;	/* file offset of this segment */
	uint32_t	filesize;	/* amount to map from the file */
	vm_prot_t	maxprot;	/* maximum VM protection */
	vm_prot_t	initprot;	/* initial VM protection */
	uint32_t	nsects;		/* number of sections in segment */
	uint32_t	flags;		/* flags */
};

/*
* The 64-bit segment load command indicates that a part of this file is to be
* mapped into a 64-bit task's address space.  If the 64-bit segment has
* sections then section_64 structures directly follow the 64-bit segment
* command and their size is reflected in cmdsize.
*/
struct segment_command_64 { /* for 64-bit architectures */
	uint32_t	cmd;		/* LC_SEGMENT_64 */
	uint32_t	cmdsize;	/* includes sizeof section_64 structs */
	char		segname[16];	/* segment name */
	uint64_t	vmaddr;		/* memory address of this segment */
	uint64_t	vmsize;		/* memory size of this segment */
	uint64_t	fileoff;	/* file offset of this segment */
	uint64_t	filesize;	/* amount to map from the file */
	vm_prot_t	maxprot;	/* maximum VM protection */
	vm_prot_t	initprot;	/* initial VM protection */
	uint32_t	nsects;		/* number of sections in segment */
	uint32_t	flags;		/* flags */
};

/* Constants for the flags field of the segment_command */
#define	SG_HIGHVM	0x1	/* the file contents for this segment is for
the high part of the VM space, the low part
is zero filled (for stacks in core files) */
#define	SG_FVMLIB	0x2	/* this segment is the VM that is allocated by
a fixed VM library, for overlap checking in
the link editor */
#define	SG_NORELOC	0x4	/* this segment has nothing that was relocated
in it and nothing relocated to it, that is
it maybe safely replaced without relocation*/
#define SG_PROTECTED_VERSION_1	0x8 /* This segment is protected.  If the
segment starts at file offset 0, the
first page of the segment is not
protected.  All other pages of the
segment are protected. */

/*
* A segment is made up of zero or more sections.  Non-MH_OBJECT files have
* all of their segments with the proper sections in each, and padded to the
* specified segment alignment when produced by the link editor.  The first
* segment of a MH_EXECUTE and MH_FVMLIB format file contains the mach_header
* and load commands of the object file before its first section.  The zero
* fill sections are always last in their segment (in all formats).  This
* allows the zeroed segment padding to be mapped into memory where zero fill
* sections might be. The gigabyte zero fill sections, those with the section
* type S_GB_ZEROFILL, can only be in a segment with sections of this type.
* These segments are then placed after all other segments.
*
* The MH_OBJECT format has all of its sections in one segment for
* compactness.  There is no padding to a specified segment boundary and the
* mach_header and load commands are not part of the segment.
*
* Sections with the same section name, sectname, going into the same segment,
* segname, are combined by the link editor.  The resulting section is aligned
* to the maximum alignment of the combined sections and is the new section's
* alignment.  The combined sections are aligned to their original alignment in
* the combined section.  Any padded bytes to get the specified alignment are
* zeroed.
*
* The format of the relocation entries referenced by the reloff and nreloc
* fields of the section structure for mach object files is described in the
* header file <reloc.h>.
*/
struct section { /* for 32-bit architectures */
	char		sectname[16];	/* name of this section */
	char		segname[16];	/* segment this section goes in */
	uint32_t	addr;		/* memory address of this section */
	uint32_t	size;		/* size in bytes of this section */
	uint32_t	offset;		/* file offset of this section */
	uint32_t	align;		/* section alignment (power of 2) */
	uint32_t	reloff;		/* file offset of relocation entries */
	uint32_t	nreloc;		/* number of relocation entries */
	uint32_t	flags;		/* flags (section type and attributes)*/
	uint32_t	reserved1;	/* reserved (for offset or index) */
	uint32_t	reserved2;	/* reserved (for count or sizeof) */
};

struct section_64 { /* for 64-bit architectures */
	char		sectname[16];	/* name of this section */
	char		segname[16];	/* segment this section goes in */
	uint64_t	addr;		/* memory address of this section */
	uint64_t	size;		/* size in bytes of this section */
	uint32_t	offset;		/* file offset of this section */
	uint32_t	align;		/* section alignment (power of 2) */
	uint32_t	reloff;		/* file offset of relocation entries */
	uint32_t	nreloc;		/* number of relocation entries */
	uint32_t	flags;		/* flags (section type and attributes)*/
	uint32_t	reserved1;	/* reserved (for offset or index) */
	uint32_t	reserved2;	/* reserved (for count or sizeof) */
	uint32_t	reserved3;	/* reserved */
};

/*
* The flags field of a section structure is separated into two parts a section
* type and section attributes.  The section types are mutually exclusive (it
* can only have one type) but the section attributes are not (it may have more
* than one attribute).
*/
#define SECTION_TYPE		 0x000000ff	/* 256 section types */
#define SECTION_ATTRIBUTES	 0xffffff00	/*  24 section attributes */

/* Constants for the type of a section */
#define	S_REGULAR		0x0	/* regular section */
#define	S_ZEROFILL		0x1	/* zero fill on demand section */
#define	S_CSTRING_LITERALS	0x2	/* section with only literal C strings*/
#define	S_4BYTE_LITERALS	0x3	/* section with only 4 byte literals */
#define	S_8BYTE_LITERALS	0x4	/* section with only 8 byte literals */
#define	S_LITERAL_POINTERS	0x5	/* section with only pointers to */
/*  literals */
/*
* For the two types of symbol pointers sections and the symbol stubs section
* they have indirect symbol table entries.  For each of the entries in the
* section the indirect symbol table entries, in corresponding order in the
* indirect symbol table, start at the index stored in the reserved1 field
* of the section structure.  Since the indirect symbol table entries
* correspond to the entries in the section the number of indirect symbol table
* entries is inferred from the size of the section divided by the size of the
* entries in the section.  For symbol pointers sections the size of the entries
* in the section is 4 bytes and for symbol stubs sections the byte size of the
* stubs is stored in the reserved2 field of the section structure.
*/
#define	S_NON_LAZY_SYMBOL_POINTERS	0x6	/* section with only non-lazy
symbol pointers */
#define	S_LAZY_SYMBOL_POINTERS		0x7	/* section with only lazy symbol
pointers */
#define	S_SYMBOL_STUBS			0x8	/* section with only symbol
stubs, byte size of stub in
the reserved2 field */
#define	S_MOD_INIT_FUNC_POINTERS	0x9	/* section with only function
pointers for initialization*/
#define	S_MOD_TERM_FUNC_POINTERS	0xa	/* section with only function
pointers for termination */
#define	S_COALESCED			0xb	/* section contains symbols that
are to be coalesced */
#define	S_GB_ZEROFILL			0xc	/* zero fill on demand section
(that can be larger than 4
gigabytes) */
#define	S_INTERPOSING			0xd	/* section with only pairs of
function pointers for
interposing */
#define	S_16BYTE_LITERALS		0xe	/* section with only 16 byte
literals */
#define	S_DTRACE_DOF			0xf	/* section contains 
DTrace Object Format */
#define	S_LAZY_DYLIB_SYMBOL_POINTERS	0x10	/* section with only lazy
symbol pointers to lazy
loaded dylibs */
/*
* Section types to support thread local variables
*/
#define S_THREAD_LOCAL_REGULAR                   0x11  /* template of initial 
values for TLVs */
#define S_THREAD_LOCAL_ZEROFILL                  0x12  /* template of initial 
values for TLVs */
#define S_THREAD_LOCAL_VARIABLES                 0x13  /* TLV descriptors */
#define S_THREAD_LOCAL_VARIABLE_POINTERS         0x14  /* pointers to TLV 
descriptors */
#define S_THREAD_LOCAL_INIT_FUNCTION_POINTERS    0x15  /* functions to call
to initialize TLV
values */

/*
* Constants for the section attributes part of the flags field of a section
* structure.
*/
#define SECTION_ATTRIBUTES_USR	 0xff000000	/* User setable attributes */
#define S_ATTR_PURE_INSTRUCTIONS 0x80000000	/* section contains only true
machine instructions */
#define S_ATTR_NO_TOC 		 0x40000000	/* section contains coalesced
symbols that are not to be
in a ranlib table of
contents */
#define S_ATTR_STRIP_STATIC_SYMS 0x20000000	/* ok to strip static symbols
in this section in files
with the MH_DYLDLINK flag */
#define S_ATTR_NO_DEAD_STRIP	 0x10000000	/* no dead stripping */
#define S_ATTR_LIVE_SUPPORT	 0x08000000	/* blocks are live if they
reference live blocks */
#define S_ATTR_SELF_MODIFYING_CODE 0x04000000	/* Used with i386 code stubs
written on by dyld */
/*
* If a segment contains any sections marked with S_ATTR_DEBUG then all
* sections in that segment must have this attribute.  No section other than
* a section marked with this attribute may reference the contents of this
* section.  A section with this attribute may contain no symbols and must have
* a section type S_REGULAR.  The static linker will not copy section contents
* from sections with this attribute into its output file.  These sections
* generally contain DWARF debugging info.
*/
#define	S_ATTR_DEBUG		 0x02000000	/* a debug section */
#define SECTION_ATTRIBUTES_SYS	 0x00ffff00	/* system setable attributes */
#define S_ATTR_SOME_INSTRUCTIONS 0x00000400	/* section contains some
machine instructions */
#define S_ATTR_EXT_RELOC	 0x00000200	/* section has external
relocation entries */
#define S_ATTR_LOC_RELOC	 0x00000100	/* section has local
relocation entries */


/*
* The names of segments and sections in them are mostly meaningless to the
* link-editor.  But there are few things to support traditional UNIX
* executables that require the link-editor and assembler to use some names
* agreed upon by convention.
*
* The initial protection of the "__TEXT" segment has write protection turned
* off (not writeable).
*
* The link-editor will allocate common symbols at the end of the "__common"
* section in the "__DATA" segment.  It will create the section and segment
* if needed.
*/

/* The currently known segment names and the section names in those segments */

#define	SEG_PAGEZERO	"__PAGEZERO"	/* the pagezero segment which has no */
/* protections and catches NULL */
/* references for MH_EXECUTE files */


#define	SEG_TEXT	"__TEXT"	/* the tradition UNIX text segment */
#define	SECT_TEXT	"__text"	/* the real text part of the text */
/* section no headers, and no padding */
#define SECT_FVMLIB_INIT0 "__fvmlib_init0"	/* the fvmlib initialization */
/*  section */
#define SECT_FVMLIB_INIT1 "__fvmlib_init1"	/* the section following the */
/*  fvmlib initialization */
/*  section */

#define	SEG_DATA	"__DATA"	/* the tradition UNIX data segment */
#define	SECT_DATA	"__data"	/* the real initialized data section */
/* no padding, no bss overlap */
#define	SECT_BSS	"__bss"		/* the real uninitialized data section*/
/* no padding */
#define SECT_COMMON	"__common"	/* the section common symbols are */
/* allocated in by the link editor */

#define	SEG_OBJC	"__OBJC"	/* objective-C runtime segment */
#define SECT_OBJC_SYMBOLS "__symbol_table"	/* symbol table */
#define SECT_OBJC_MODULES "__module_info"	/* module information */
#define SECT_OBJC_STRINGS "__selector_strs"	/* string table */
#define SECT_OBJC_REFS "__selector_refs"	/* string table */

#define	SEG_ICON	 "__ICON"	/* the icon segment */
#define	SECT_ICON_HEADER "__header"	/* the icon headers */
#define	SECT_ICON_TIFF   "__tiff"	/* the icons in tiff format */

#define	SEG_LINKEDIT	"__LINKEDIT"	/* the segment containing all structs */
/* created and maintained by the link */
/* editor.  Created with -seglinkedit */
/* option to ld(1) for MH_EXECUTE and */
/* FVMLIB file types only */

#define SEG_UNIXSTACK	"__UNIXSTACK"	/* the unix stack segment */

#define SEG_IMPORT	"__IMPORT"	/* the segment for the self (dyld) */
/* modifing code stubs that has read, */
/* write and execute permissions */

/*
* Fixed virtual memory shared libraries are identified by two things.  The
* target pathname (the name of the library as found for execution), and the
* minor version number.  The address of where the headers are loaded is in
* header_addr. (THIS IS OBSOLETE and no longer supported).
*/
struct fvmlib {
	union lc_str	name;		/* library's target pathname */
	uint32_t	minor_version;	/* library's minor version number */
	uint32_t	header_addr;	/* library's header address */
};

/*
* A fixed virtual shared library (filetype == MH_FVMLIB in the mach header)
* contains a fvmlib_command (cmd == LC_IDFVMLIB) to identify the library.
* An object that uses a fixed virtual shared library also contains a
* fvmlib_command (cmd == LC_LOADFVMLIB) for each library it uses.
* (THIS IS OBSOLETE and no longer supported).
*/
struct fvmlib_command {
	uint32_t	cmd;		/* LC_IDFVMLIB or LC_LOADFVMLIB */
	uint32_t	cmdsize;	/* includes pathname string */
	struct fvmlib	fvmlib;		/* the library identification */
};

/*
* Dynamicly linked shared libraries are identified by two things.  The
* pathname (the name of the library as found for execution), and the
* compatibility version number.  The pathname must match and the compatibility
* number in the user of the library must be greater than or equal to the
* library being used.  The time stamp is used to record the time a library was
* built and copied into user so it can be use to determined if the library used
* at runtime is exactly the same as used to built the program.
*/
struct dylib {
	union lc_str  name;			/* library's path name */
	uint32_t timestamp;			/* library's build time stamp */
	uint32_t current_version;		/* library's current version number */
	uint32_t compatibility_version;	/* library's compatibility vers number*/
};

/*
* A dynamically linked shared library (filetype == MH_DYLIB in the mach header)
* contains a dylib_command (cmd == LC_ID_DYLIB) to identify the library.
* An object that uses a dynamically linked shared library also contains a
* dylib_command (cmd == LC_LOAD_DYLIB, LC_LOAD_WEAK_DYLIB, or
* LC_REEXPORT_DYLIB) for each library it uses.
*/
struct dylib_command {
	uint32_t	cmd;		/* LC_ID_DYLIB, LC_LOAD_{,WEAK_}DYLIB,
							LC_REEXPORT_DYLIB */
	uint32_t	cmdsize;	/* includes pathname string */
	struct dylib	dylib;		/* the library identification */
};

/*
* A dynamically linked shared library may be a subframework of an umbrella
* framework.  If so it will be linked with "-umbrella umbrella_name" where
* Where "umbrella_name" is the name of the umbrella framework. A subframework
* can only be linked against by its umbrella framework or other subframeworks
* that are part of the same umbrella framework.  Otherwise the static link
* editor produces an error and states to link against the umbrella framework.
* The name of the umbrella framework for subframeworks is recorded in the
* following structure.
*/
struct sub_framework_command {
	uint32_t	cmd;		/* LC_SUB_FRAMEWORK */
	uint32_t	cmdsize;	/* includes umbrella string */
	union lc_str 	umbrella;	/* the umbrella framework name */
};

/*
* For dynamically linked shared libraries that are subframework of an umbrella
* framework they can allow clients other than the umbrella framework or other
* subframeworks in the same umbrella framework.  To do this the subframework
* is built with "-allowable_client client_name" and an LC_SUB_CLIENT load
* command is created for each -allowable_client flag.  The client_name is
* usually a framework name.  It can also be a name used for bundles clients
* where the bundle is built with "-client_name client_name".
*/
struct sub_client_command {
	uint32_t	cmd;		/* LC_SUB_CLIENT */
	uint32_t	cmdsize;	/* includes client string */
	union lc_str 	client;		/* the client name */
};

/*
* A dynamically linked shared library may be a sub_umbrella of an umbrella
* framework.  If so it will be linked with "-sub_umbrella umbrella_name" where
* Where "umbrella_name" is the name of the sub_umbrella framework.  When
* staticly linking when -twolevel_namespace is in effect a twolevel namespace
* umbrella framework will only cause its subframeworks and those frameworks
* listed as sub_umbrella frameworks to be implicited linked in.  Any other
* dependent dynamic libraries will not be linked it when -twolevel_namespace
* is in effect.  The primary library recorded by the static linker when
* resolving a symbol in these libraries will be the umbrella framework.
* Zero or more sub_umbrella frameworks may be use by an umbrella framework.
* The name of a sub_umbrella framework is recorded in the following structure.
*/
struct sub_umbrella_command {
	uint32_t	cmd;		/* LC_SUB_UMBRELLA */
	uint32_t	cmdsize;	/* includes sub_umbrella string */
	union lc_str 	sub_umbrella;	/* the sub_umbrella framework name */
};

/*
* A dynamically linked shared library may be a sub_library of another shared
* library.  If so it will be linked with "-sub_library library_name" where
* Where "library_name" is the name of the sub_library shared library.  When
* staticly linking when -twolevel_namespace is in effect a twolevel namespace
* shared library will only cause its subframeworks and those frameworks
* listed as sub_umbrella frameworks and libraries listed as sub_libraries to
* be implicited linked in.  Any other dependent dynamic libraries will not be
* linked it when -twolevel_namespace is in effect.  The primary library
* recorded by the static linker when resolving a symbol in these libraries
* will be the umbrella framework (or dynamic library). Zero or more sub_library
* shared libraries may be use by an umbrella framework or (or dynamic library).
* The name of a sub_library framework is recorded in the following structure.
* For example /usr/lib/libobjc_profile.A.dylib would be recorded as "libobjc".
*/
struct sub_library_command {
	uint32_t	cmd;		/* LC_SUB_LIBRARY */
	uint32_t	cmdsize;	/* includes sub_library string */
	union lc_str 	sub_library;	/* the sub_library name */
};

/*
* A program (filetype == MH_EXECUTE) that is
* prebound to its dynamic libraries has one of these for each library that
* the static linker used in prebinding.  It contains a bit vector for the
* modules in the library.  The bits indicate which modules are bound (1) and
* which are not (0) from the library.  The bit for module 0 is the low bit
* of the first byte.  So the bit for the Nth module is:
* (linked_modules[N/8] >> N%8) & 1
*/
struct prebound_dylib_command {
	uint32_t	cmd;		/* LC_PREBOUND_DYLIB */
	uint32_t	cmdsize;	/* includes strings */
	union lc_str	name;		/* library's path name */
	uint32_t	nmodules;	/* number of modules in library */
	union lc_str	linked_modules;	/* bit vector of linked modules */
};

/*
* A program that uses a dynamic linker contains a dylinker_command to identify
* the name of the dynamic linker (LC_LOAD_DYLINKER).  And a dynamic linker
* contains a dylinker_command to identify the dynamic linker (LC_ID_DYLINKER).
* A file can have at most one of these.
* This struct is also used for the LC_DYLD_ENVIRONMENT load command and
* contains string for dyld to treat like environment variable.
*/
struct dylinker_command {
	uint32_t	cmd;		/* LC_ID_DYLINKER, LC_LOAD_DYLINKER or
							LC_DYLD_ENVIRONMENT */
	uint32_t	cmdsize;	/* includes pathname string */
	union lc_str    name;		/* dynamic linker's path name */
};

/*
* Thread commands contain machine-specific data structures suitable for
* use in the thread state primitives.  The machine specific data structures
* follow the struct thread_command as follows.
* Each flavor of machine specific data structure is preceded by an unsigned
* long constant for the flavor of that data structure, an uint32_t
* that is the count of longs of the size of the state data structure and then
* the state data structure follows.  This triple may be repeated for many
* flavors.  The constants for the flavors, counts and state data structure
* definitions are expected to be in the header file <machine/thread_status.h>.
* These machine specific data structures sizes must be multiples of
* 4 bytes  The cmdsize reflects the total size of the thread_command
* and all of the sizes of the constants for the flavors, counts and state
* data structures.
*
* For executable objects that are unix processes there will be one
* thread_command (cmd == LC_UNIXTHREAD) created for it by the link-editor.
* This is the same as a LC_THREAD, except that a stack is automatically
* created (based on the shell's limit for the stack size).  Command arguments
* and environment variables are copied onto that stack.
*/
struct thread_command {
	uint32_t	cmd;		/* LC_THREAD or  LC_UNIXTHREAD */
	uint32_t	cmdsize;	/* total size of this command */
							/* uint32_t flavor		   flavor of thread state */
							/* uint32_t count		   count of longs in thread state */
							/* struct XXX_thread_state state   thread state for this flavor */
							/* ... */
};

/*
* The routines command contains the address of the dynamic shared library
* initialization routine and an index into the module table for the module
* that defines the routine.  Before any modules are used from the library the
* dynamic linker fully binds the module that defines the initialization routine
* and then calls it.  This gets called before any module initialization
* routines (used for C++ static constructors) in the library.
*/
struct routines_command { /* for 32-bit architectures */
	uint32_t	cmd;		/* LC_ROUTINES */
	uint32_t	cmdsize;	/* total size of this command */
	uint32_t	init_address;	/* address of initialization routine */
	uint32_t	init_module;	/* index into the module table that */
								/*  the init routine is defined in */
	uint32_t	reserved1;
	uint32_t	reserved2;
	uint32_t	reserved3;
	uint32_t	reserved4;
	uint32_t	reserved5;
	uint32_t	reserved6;
};

/*
* The 64-bit routines command.  Same use as above.
*/
struct routines_command_64 { /* for 64-bit architectures */
	uint32_t	cmd;		/* LC_ROUTINES_64 */
	uint32_t	cmdsize;	/* total size of this command */
	uint64_t	init_address;	/* address of initialization routine */
	uint64_t	init_module;	/* index into the module table that */
								/*  the init routine is defined in */
	uint64_t	reserved1;
	uint64_t	reserved2;
	uint64_t	reserved3;
	uint64_t	reserved4;
	uint64_t	reserved5;
	uint64_t	reserved6;
};

/*
* The symtab_command contains the offsets and sizes of the link-edit 4.3BSD
* "stab" style symbol table information as described in the header files
* <nlist.h> and <stab.h>.
*/
struct symtab_command {
	uint32_t	cmd;		/* LC_SYMTAB */
	uint32_t	cmdsize;	/* sizeof(struct symtab_command) */
	uint32_t	symoff;		/* symbol table offset */
	uint32_t	nsyms;		/* number of symbol table entries */
	uint32_t	stroff;		/* string table offset */
	uint32_t	strsize;	/* string table size in bytes */
};

/*
* This is the second set of the symbolic information which is used to support
* the data structures for the dynamically link editor.
*
* The original set of symbolic information in the symtab_command which contains
* the symbol and string tables must also be present when this load command is
* present.  When this load command is present the symbol table is organized
* into three groups of symbols:
*	local symbols (static and debugging symbols) - grouped by module
*	defined external symbols - grouped by module (sorted by name if not lib)
*	undefined external symbols (sorted by name if MH_BINDATLOAD is not set,
*	     			    and in order the were seen by the static
*				    linker if MH_BINDATLOAD is set)
* In this load command there are offsets and counts to each of the three groups
* of symbols.
*
* This load command contains a the offsets and sizes of the following new
* symbolic information tables:
*	table of contents
*	module table
*	reference symbol table
*	indirect symbol table
* The first three tables above (the table of contents, module table and
* reference symbol table) are only present if the file is a dynamically linked
* shared library.  For executable and object modules, which are files
* containing only one module, the information that would be in these three
* tables is determined as follows:
* 	table of contents - the defined external symbols are sorted by name
*	module table - the file contains only one module so everything in the
*		       file is part of the module.
*	reference symbol table - is the defined and undefined external symbols
*
* For dynamically linked shared library files this load command also contains
* offsets and sizes to the pool of relocation entries for all sections
* separated into two groups:
*	external relocation entries
*	local relocation entries
* For executable and object modules the relocation entries continue to hang
* off the section structures.
*/
struct dysymtab_command {
	uint32_t cmd;	/* LC_DYSYMTAB */
	uint32_t cmdsize;	/* sizeof(struct dysymtab_command) */

						/*
						* The symbols indicated by symoff and nsyms of the LC_SYMTAB load command
						* are grouped into the following three groups:
						*    local symbols (further grouped by the module they are from)
						*    defined external symbols (further grouped by the module they are from)
						*    undefined symbols
						*
						* The local symbols are used only for debugging.  The dynamic binding
						* process may have to use them to indicate to the debugger the local
						* symbols for a module that is being bound.
						*
						* The last two groups are used by the dynamic binding process to do the
						* binding (indirectly through the module table and the reference symbol
						* table when this is a dynamically linked shared library file).
						*/
	uint32_t ilocalsym;	/* index to local symbols */
	uint32_t nlocalsym;	/* number of local symbols */

	uint32_t iextdefsym;/* index to externally defined symbols */
	uint32_t nextdefsym;/* number of externally defined symbols */

	uint32_t iundefsym;	/* index to undefined symbols */
	uint32_t nundefsym;	/* number of undefined symbols */

						/*
						* For the for the dynamic binding process to find which module a symbol
						* is defined in the table of contents is used (analogous to the ranlib
						* structure in an archive) which maps defined external symbols to modules
						* they are defined in.  This exists only in a dynamically linked shared
						* library file.  For executable and object modules the defined external
						* symbols are sorted by name and is use as the table of contents.
						*/
	uint32_t tocoff;	/* file offset to table of contents */
	uint32_t ntoc;	/* number of entries in table of contents */

					/*
					* To support dynamic binding of "modules" (whole object files) the symbol
					* table must reflect the modules that the file was created from.  This is
					* done by having a module table that has indexes and counts into the merged
					* tables for each module.  The module structure that these two entries
					* refer to is described below.  This exists only in a dynamically linked
					* shared library file.  For executable and object modules the file only
					* contains one module so everything in the file belongs to the module.
					*/
	uint32_t modtaboff;	/* file offset to module table */
	uint32_t nmodtab;	/* number of module table entries */

						/*
						* To support dynamic module binding the module structure for each module
						* indicates the external references (defined and undefined) each module
						* makes.  For each module there is an offset and a count into the
						* reference symbol table for the symbols that the module references.
						* This exists only in a dynamically linked shared library file.  For
						* executable and object modules the defined external symbols and the
						* undefined external symbols indicates the external references.
						*/
	uint32_t extrefsymoff;	/* offset to referenced symbol table */
	uint32_t nextrefsyms;	/* number of referenced symbol table entries */

							/*
							* The sections that contain "symbol pointers" and "routine stubs" have
							* indexes and (implied counts based on the size of the section and fixed
							* size of the entry) into the "indirect symbol" table for each pointer
							* and stub.  For every section of these two types the index into the
							* indirect symbol table is stored in the section header in the field
							* reserved1.  An indirect symbol table entry is simply a 32bit index into
							* the symbol table to the symbol that the pointer or stub is referring to.
							* The indirect symbol table is ordered to match the entries in the section.
							*/
	uint32_t indirectsymoff; /* file offset to the indirect symbol table */
	uint32_t nindirectsyms;  /* number of indirect symbol table entries */

							 /*
							 * To support relocating an individual module in a library file quickly the
							 * external relocation entries for each module in the library need to be
							 * accessed efficiently.  Since the relocation entries can't be accessed
							 * through the section headers for a library file they are separated into
							 * groups of local and external entries further grouped by module.  In this
							 * case the presents of this load command who's extreloff, nextrel,
							 * locreloff and nlocrel fields are non-zero indicates that the relocation
							 * entries of non-merged sections are not referenced through the section
							 * structures (and the reloff and nreloc fields in the section headers are
							 * set to zero).
							 *
							 * Since the relocation entries are not accessed through the section headers
							 * this requires the r_address field to be something other than a section
							 * offset to identify the item to be relocated.  In this case r_address is
							 * set to the offset from the vmaddr of the first LC_SEGMENT command.
							 * For MH_SPLIT_SEGS images r_address is set to the the offset from the
							 * vmaddr of the first read-write LC_SEGMENT command.
							 *
							 * The relocation entries are grouped by module and the module table
							 * entries have indexes and counts into them for the group of external
							 * relocation entries for that the module.
							 *
							 * For sections that are merged across modules there must not be any
							 * remaining external relocation entries for them (for merged sections
							 * remaining relocation entries must be local).
							 */
	uint32_t extreloff;	/* offset to external relocation entries */
	uint32_t nextrel;	/* number of external relocation entries */

						/*
						* All the local relocation entries are grouped together (they are not
						* grouped by their module since they are only used if the object is moved
						* from it staticly link edited address).
						*/
	uint32_t locreloff;	/* offset to local relocation entries */
	uint32_t nlocrel;	/* number of local relocation entries */

};

/*
* An indirect symbol table entry is simply a 32bit index into the symbol table
* to the symbol that the pointer or stub is refering to.  Unless it is for a
* non-lazy symbol pointer section for a defined symbol which strip(1) as
* removed.  In which case it has the value INDIRECT_SYMBOL_LOCAL.  If the
* symbol was also absolute INDIRECT_SYMBOL_ABS is or'ed with that.
*/
#define INDIRECT_SYMBOL_LOCAL	0x80000000
#define INDIRECT_SYMBOL_ABS	0x40000000


/* a table of contents entry */
struct dylib_table_of_contents {
	uint32_t symbol_index;	/* the defined external symbol
							(index into the symbol table) */
	uint32_t module_index;	/* index into the module table this symbol
							is defined in */
};

/* a module table entry */
struct dylib_module {
	uint32_t module_name;	/* the module name (index into string table) */

	uint32_t iextdefsym;	/* index into externally defined symbols */
	uint32_t nextdefsym;	/* number of externally defined symbols */
	uint32_t irefsym;		/* index into reference symbol table */
	uint32_t nrefsym;		/* number of reference symbol table entries */
	uint32_t ilocalsym;		/* index into symbols for local symbols */
	uint32_t nlocalsym;		/* number of local symbols */

	uint32_t iextrel;		/* index into external relocation entries */
	uint32_t nextrel;		/* number of external relocation entries */

	uint32_t iinit_iterm;	/* low 16 bits are the index into the init
							section, high 16 bits are the index into
							the term section */
	uint32_t ninit_nterm;	/* low 16 bits are the number of init section
							entries, high 16 bits are the number of
							term section entries */

	uint32_t			/* for this module address of the start of */
		objc_module_info_addr;  /*  the (__OBJC,__module_info) section */
	uint32_t			/* for this module size of */
		objc_module_info_size;	/*  the (__OBJC,__module_info) section */
};

/* a 64-bit module table entry */
struct dylib_module_64 {
	uint32_t module_name;	/* the module name (index into string table) */

	uint32_t iextdefsym;	/* index into externally defined symbols */
	uint32_t nextdefsym;	/* number of externally defined symbols */
	uint32_t irefsym;		/* index into reference symbol table */
	uint32_t nrefsym;		/* number of reference symbol table entries */
	uint32_t ilocalsym;		/* index into symbols for local symbols */
	uint32_t nlocalsym;		/* number of local symbols */

	uint32_t iextrel;		/* index into external relocation entries */
	uint32_t nextrel;		/* number of external relocation entries */

	uint32_t iinit_iterm;	/* low 16 bits are the index into the init
							section, high 16 bits are the index into
							the term section */
	uint32_t ninit_nterm;      /* low 16 bits are the number of init section
							   entries, high 16 bits are the number of
							   term section entries */

	uint32_t			/* for this module size of */
		objc_module_info_size;	/*  the (__OBJC,__module_info) section */
	uint64_t			/* for this module address of the start of */
		objc_module_info_addr;	/*  the (__OBJC,__module_info) section */
};

/*
* The entries in the reference symbol table are used when loading the module
* (both by the static and dynamic link editors) and if the module is unloaded
* or replaced.  Therefore all external symbols (defined and undefined) are
* listed in the module's reference table.  The flags describe the type of
* reference that is being made.  The constants for the flags are defined in
* <mach-o/nlist.h> as they are also used for symbol table entries.
*/
struct dylib_reference {
	uint32_t isym : 24,		/* index into the symbol table */
		flags : 8;	/* flags to indicate the type of reference */
};

/*
* The twolevel_hints_command contains the offset and number of hints in the
* two-level namespace lookup hints table.
*/
struct twolevel_hints_command {
	uint32_t cmd;	/* LC_TWOLEVEL_HINTS */
	uint32_t cmdsize;	/* sizeof(struct twolevel_hints_command) */
	uint32_t offset;	/* offset to the hint table */
	uint32_t nhints;	/* number of hints in the hint table */
};

/*
* The entries in the two-level namespace lookup hints table are twolevel_hint
* structs.  These provide hints to the dynamic link editor where to start
* looking for an undefined symbol in a two-level namespace image.  The
* isub_image field is an index into the sub-images (sub-frameworks and
* sub-umbrellas list) that made up the two-level image that the undefined
* symbol was found in when it was built by the static link editor.  If
* isub-image is 0 the the symbol is expected to be defined in library and not
* in the sub-images.  If isub-image is non-zero it is an index into the array
* of sub-images for the umbrella with the first index in the sub-images being
* 1. The array of sub-images is the ordered list of sub-images of the umbrella
* that would be searched for a symbol that has the umbrella recorded as its
* primary library.  The table of contents index is an index into the
* library's table of contents.  This is used as the starting point of the
* binary search or a directed linear search.
*/
struct twolevel_hint {
	uint32_t
		isub_image : 8,	/* index into the sub images */
		itoc : 24;	/* index into the table of contents */
};

/*
* The prebind_cksum_command contains the value of the original check sum for
* prebound files or zero.  When a prebound file is first created or modified
* for other than updating its prebinding information the value of the check sum
* is set to zero.  When the file has it prebinding re-done and if the value of
* the check sum is zero the original check sum is calculated and stored in
* cksum field of this load command in the output file.  If when the prebinding
* is re-done and the cksum field is non-zero it is left unchanged from the
* input file.
*/
struct prebind_cksum_command {
	uint32_t cmd;	/* LC_PREBIND_CKSUM */
	uint32_t cmdsize;	/* sizeof(struct prebind_cksum_command) */
	uint32_t cksum;	/* the check sum or zero */
};

/*
* The uuid load command contains a single 128-bit unique random number that
* identifies an object produced by the static link editor.
*/
struct uuid_command {
	uint32_t	cmd;		/* LC_UUID */
	uint32_t	cmdsize;	/* sizeof(struct uuid_command) */
	uint8_t	uuid[16];	/* the 128-bit uuid */
};

/*
* The rpath_command contains a path which at runtime should be added to
* the current run path used to find @rpath prefixed dylibs.
*/
struct rpath_command {
	uint32_t	 cmd;		/* LC_RPATH */
	uint32_t	 cmdsize;	/* includes string */
	union lc_str path;		/* path to add to run path */
};

/*
* The linkedit_data_command contains the offsets and sizes of a blob
* of data in the __LINKEDIT segment.
*/
struct linkedit_data_command {
	uint32_t	cmd;		/* LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO,
							LC_FUNCTION_STARTS, LC_DATA_IN_CODE,
							LC_DYLIB_CODE_SIGN_DRS or
							LC_LINKER_OPTIMIZATION_HINT. */
	uint32_t	cmdsize;	/* sizeof(struct linkedit_data_command) */
	uint32_t	dataoff;	/* file offset of data in __LINKEDIT segment */
	uint32_t	datasize;	/* file size of data in __LINKEDIT segment  */
};

/*
* The encryption_info_command contains the file offset and size of an
* of an encrypted segment.
*/
struct encryption_info_command {
	uint32_t	cmd;		/* LC_ENCRYPTION_INFO */
	uint32_t	cmdsize;	/* sizeof(struct encryption_info_command) */
	uint32_t	cryptoff;	/* file offset of encrypted range */
	uint32_t	cryptsize;	/* file size of encrypted range */
	uint32_t	cryptid;	/* which enryption system,
							0 means not-encrypted yet */
};

/*
* The encryption_info_command_64 contains the file offset and size of an
* of an encrypted segment (for use in x86_64 targets).
*/
struct encryption_info_command_64 {
	uint32_t	cmd;		/* LC_ENCRYPTION_INFO_64 */
	uint32_t	cmdsize;	/* sizeof(struct encryption_info_command_64) */
	uint32_t	cryptoff;	/* file offset of encrypted range */
	uint32_t	cryptsize;	/* file size of encrypted range */
	uint32_t	cryptid;	/* which enryption system,
							0 means not-encrypted yet */
	uint32_t	pad;		/* padding to make this struct's size a multiple
							of 8 bytes */
};

/*
* The version_min_command contains the min OS version on which this
* binary was built to run.
*/
struct version_min_command {
	uint32_t	cmd;		/* LC_VERSION_MIN_MACOSX or
							LC_VERSION_MIN_IPHONEOS or
							LC_VERSION_MIN_WATCHOS or
							LC_VERSION_MIN_TVOS */
	uint32_t	cmdsize;	/* sizeof(struct min_version_command) */
	uint32_t	version;	/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
	uint32_t	sdk;		/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
};

/*
* The dyld_info_command contains the file offsets and sizes of
* the new compressed form of the information dyld needs to
* load the image.  This information is used by dyld on Mac OS X
* 10.6 and later.  All information pointed to by this command
* is encoded using byte streams, so no endian swapping is needed
* to interpret it.
*/
struct dyld_info_command {
	uint32_t   cmd;		/* LC_DYLD_INFO or LC_DYLD_INFO_ONLY */
	uint32_t   cmdsize;		/* sizeof(struct dyld_info_command) */

							/*
							* Dyld rebases an image whenever dyld loads it at an address different
							* from its preferred address.  The rebase information is a stream
							* of byte sized opcodes whose symbolic names start with REBASE_OPCODE_.
							* Conceptually the rebase information is a table of tuples:
							*    <seg-index, seg-offset, type>
							* The opcodes are a compressed way to encode the table by only
							* encoding when a column changes.  In addition simple patterns
							* like "every n'th offset for m times" can be encoded in a few
							* bytes.
							*/
	uint32_t   rebase_off;	/* file offset to rebase info  */
	uint32_t   rebase_size;	/* size of rebase info   */

							/*
							* Dyld binds an image during the loading process, if the image
							* requires any pointers to be initialized to symbols in other images.
							* The bind information is a stream of byte sized
							* opcodes whose symbolic names start with BIND_OPCODE_.
							* Conceptually the bind information is a table of tuples:
							*    <seg-index, seg-offset, type, symbol-library-ordinal, symbol-name, addend>
							* The opcodes are a compressed way to encode the table by only
							* encoding when a column changes.  In addition simple patterns
							* like for runs of pointers initialzed to the same value can be
							* encoded in a few bytes.
							*/
	uint32_t   bind_off;	/* file offset to binding info   */
	uint32_t   bind_size;	/* size of binding info  */

							/*
							* Some C++ programs require dyld to unique symbols so that all
							* images in the process use the same copy of some code/data.
							* This step is done after binding. The content of the weak_bind
							* info is an opcode stream like the bind_info.  But it is sorted
							* alphabetically by symbol name.  This enable dyld to walk
							* all images with weak binding information in order and look
							* for collisions.  If there are no collisions, dyld does
							* no updating.  That means that some fixups are also encoded
							* in the bind_info.  For instance, all calls to "operator new"
							* are first bound to libstdc++.dylib using the information
							* in bind_info.  Then if some image overrides operator new
							* that is detected when the weak_bind information is processed
							* and the call to operator new is then rebound.
							*/
	uint32_t   weak_bind_off;	/* file offset to weak binding info   */
	uint32_t   weak_bind_size;  /* size of weak binding info  */

								/*
								* Some uses of external symbols do not need to be bound immediately.
								* Instead they can be lazily bound on first use.  The lazy_bind
								* are contains a stream of BIND opcodes to bind all lazy symbols.
								* Normal use is that dyld ignores the lazy_bind section when
								* loading an image.  Instead the static linker arranged for the
								* lazy pointer to initially point to a helper function which
								* pushes the offset into the lazy_bind area for the symbol
								* needing to be bound, then jumps to dyld which simply adds
								* the offset to lazy_bind_off to get the information on what
								* to bind.
								*/
	uint32_t   lazy_bind_off;	/* file offset to lazy binding info */
	uint32_t   lazy_bind_size;  /* size of lazy binding infs */

								/*
								* The symbols exported by a dylib are encoded in a trie.  This
								* is a compact representation that factors out common prefixes.
								* It also reduces LINKEDIT pages in RAM because it encodes all
								* information (name, address, flags) in one small, contiguous range.
								* The export area is a stream of nodes.  The first node sequentially
								* is the start node for the trie.
								*
								* Nodes for a symbol start with a uleb128 that is the length of
								* the exported symbol information for the string so far.
								* If there is no exported symbol, the node starts with a zero byte.
								* If there is exported info, it follows the length.
								*
								* First is a uleb128 containing flags. Normally, it is followed by
								* a uleb128 encoded offset which is location of the content named
								* by the symbol from the mach_header for the image.  If the flags
								* is EXPORT_SYMBOL_FLAGS_REEXPORT, then following the flags is
								* a uleb128 encoded library ordinal, then a zero terminated
								* UTF8 string.  If the string is zero length, then the symbol
								* is re-export from the specified dylib with the same name.
								* If the flags is EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER, then following
								* the flags is two uleb128s: the stub offset and the resolver offset.
								* The stub is used by non-lazy pointers.  The resolver is used
								* by lazy pointers and must be called to get the actual address to use.
								*
								* After the optional exported symbol information is a byte of
								* how many edges (0-255) that this node has leaving it,
								* followed by each edge.
								* Each edge is a zero terminated UTF8 of the addition chars
								* in the symbol, followed by a uleb128 offset for the node that
								* edge points to.
								*
								*/
	uint32_t   export_off;	/* file offset to lazy binding info */
	uint32_t   export_size;	/* size of lazy binding infs */
};

/*
* The following are used to encode rebasing information
*/
#define REBASE_TYPE_POINTER					1
#define REBASE_TYPE_TEXT_ABSOLUTE32				2
#define REBASE_TYPE_TEXT_PCREL32				3

#define REBASE_OPCODE_MASK					0xF0
#define REBASE_IMMEDIATE_MASK					0x0F
#define REBASE_OPCODE_DONE					0x00
#define REBASE_OPCODE_SET_TYPE_IMM				0x10
#define REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB		0x20
#define REBASE_OPCODE_ADD_ADDR_ULEB				0x30
#define REBASE_OPCODE_ADD_ADDR_IMM_SCALED			0x40
#define REBASE_OPCODE_DO_REBASE_IMM_TIMES			0x50
#define REBASE_OPCODE_DO_REBASE_ULEB_TIMES			0x60
#define REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB			0x70
#define REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB	0x80


/*
* The following are used to encode binding information
*/
#define BIND_TYPE_POINTER					1
#define BIND_TYPE_TEXT_ABSOLUTE32				2
#define BIND_TYPE_TEXT_PCREL32					3

#define BIND_SPECIAL_DYLIB_SELF					 0
#define BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE			-1
#define BIND_SPECIAL_DYLIB_FLAT_LOOKUP				-2

#define BIND_SYMBOL_FLAGS_WEAK_IMPORT				0x1
#define BIND_SYMBOL_FLAGS_NON_WEAK_DEFINITION			0x8

#define BIND_OPCODE_MASK					0xF0
#define BIND_IMMEDIATE_MASK					0x0F
#define BIND_OPCODE_DONE					0x00
#define BIND_OPCODE_SET_DYLIB_ORDINAL_IMM			0x10
#define BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB			0x20
#define BIND_OPCODE_SET_DYLIB_SPECIAL_IMM			0x30
#define BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM		0x40
#define BIND_OPCODE_SET_TYPE_IMM				0x50
#define BIND_OPCODE_SET_ADDEND_SLEB				0x60
#define BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB			0x70
#define BIND_OPCODE_ADD_ADDR_ULEB				0x80
#define BIND_OPCODE_DO_BIND					0x90
#define BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB			0xA0
#define BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED			0xB0
#define BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB		0xC0


/*
* The following are used on the flags byte of a terminal node
* in the export information.
*/
#define EXPORT_SYMBOL_FLAGS_KIND_MASK				0x03
#define EXPORT_SYMBOL_FLAGS_KIND_REGULAR			0x00
#define EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL			0x01
#define EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION			0x04
#define EXPORT_SYMBOL_FLAGS_REEXPORT				0x08
#define EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER			0x10

/*
* The linker_option_command contains linker options embedded in object files.
*/
struct linker_option_command {
	uint32_t  cmd;	/* LC_LINKER_OPTION only used in MH_OBJECT filetypes */
	uint32_t  cmdsize;
	uint32_t  count;	/* number of strings */
						/* concatenation of zero terminated UTF8 strings.
						Zero filled at end to align */
};

/*
* The symseg_command contains the offset and size of the GNU style
* symbol table information as described in the header file <symseg.h>.
* The symbol roots of the symbol segments must also be aligned properly
* in the file.  So the requirement of keeping the offsets aligned to a
* multiple of a 4 bytes translates to the length field of the symbol
* roots also being a multiple of a long.  Also the padding must again be
* zeroed. (THIS IS OBSOLETE and no longer supported).
*/
struct symseg_command {
	uint32_t	cmd;		/* LC_SYMSEG */
	uint32_t	cmdsize;	/* sizeof(struct symseg_command) */
	uint32_t	offset;		/* symbol segment offset */
	uint32_t	size;		/* symbol segment size in bytes */
};

/*
* The ident_command contains a free format string table following the
* ident_command structure.  The strings are null terminated and the size of
* the command is padded out with zero bytes to a multiple of 4 bytes/
* (THIS IS OBSOLETE and no longer supported).
*/
struct ident_command {
	uint32_t cmd;		/* LC_IDENT */
	uint32_t cmdsize;	/* strings that follow this command */
};

/*
* The fvmfile_command contains a reference to a file to be loaded at the
* specified virtual address.  (Presently, this command is reserved for
* internal use.  The kernel ignores this command when loading a program into
* memory).
*/
struct fvmfile_command {
	uint32_t cmd;			/* LC_FVMFILE */
	uint32_t cmdsize;		/* includes pathname string */
	union lc_str	name;		/* files pathname */
	uint32_t	header_addr;	/* files virtual address */
};


/*
* The entry_point_command is a replacement for thread_command.
* It is used for main executables to specify the location (file offset)
* of main().  If -stack_size was used at link time, the stacksize
* field will contain the stack size need for the main thread.
*/
struct entry_point_command {
	uint32_t  cmd;	/* LC_MAIN only used in MH_EXECUTE filetypes */
	uint32_t  cmdsize;	/* 24 */
	uint64_t  entryoff;	/* file (__TEXT) offset of main() */
	uint64_t  stacksize;/* if not zero, initial stack size */
};


/*
* The source_version_command is an optional load command containing
* the version of the sources used to build the binary.
*/
struct source_version_command {
	uint32_t  cmd;	/* LC_SOURCE_VERSION */
	uint32_t  cmdsize;	/* 16 */
	uint64_t  version;	/* A.B.C.D.E packed as a24.b10.c10.d10.e10 */
};


/*
* The LC_DATA_IN_CODE load commands uses a linkedit_data_command
* to point to an array of data_in_code_entry entries. Each entry
* describes a range of data in a code section.
*/
struct data_in_code_entry {
	uint32_t	offset;  /* from mach_header to start of data range*/
	uint16_t	length;  /* number of bytes in data range */
	uint16_t	kind;    /* a DICE_KIND_* value  */
};
#define DICE_KIND_DATA              0x0001
#define DICE_KIND_JUMP_TABLE8       0x0002
#define DICE_KIND_JUMP_TABLE16      0x0003
#define DICE_KIND_JUMP_TABLE32      0x0004
#define DICE_KIND_ABS_JUMP_TABLE32  0x0005

/*
* Sections of type S_THREAD_LOCAL_VARIABLES contain an array
* of tlv_descriptor structures.
*/
struct tlv_descriptor
{
	void*		(*thunk)(struct tlv_descriptor*);
	unsigned long	key;
	unsigned long	offset;
};

/*
* Format of a symbol table entry of a Mach-O file for 32-bit architectures.
* Modified from the BSD format.  The modifications from the original format
* were changing n_other (an unused field) to n_sect and the addition of the
* N_SECT type.  These modifications are required to support symbols in a larger
* number of sections not just the three sections (text, data and bss) in a BSD
* file.
*/
struct nlist {
	union {
#ifndef __LP64__
		char *n_name;	/* for use when in-core */
#endif
		uint32_t n_strx;	/* index into the string table */
	} n_un;
	uint8_t n_type;		/* type flag, see below */
	uint8_t n_sect;		/* section number or NO_SECT */
	int16_t n_desc;		/* see <mach-o/stab.h> */
	uint32_t n_value;	/* value of this symbol (or stab offset) */
};

/*
* This is the symbol table entry structure for 64-bit architectures.
*/
struct nlist_64 {
	union {
		uint32_t  n_strx; /* index into the string table */
	} n_un;
	uint8_t n_type;        /* type flag, see below */
	uint8_t n_sect;        /* section number or NO_SECT */
	uint16_t n_desc;       /* see <mach-o/stab.h> */
	uint64_t n_value;      /* value of this symbol (or stab offset) */
};

/*
* Symbols with a index into the string table of zero (n_un.n_strx == 0) are
* defined to have a null, "", name.  Therefore all string indexes to non null
* names must not have a zero string index.  This is bit historical information
* that has never been well documented.
*/

/*
* The n_type field really contains four fields:
*	unsigned char N_STAB:3,
*		      N_PEXT:1,
*		      N_TYPE:3,
*		      N_EXT:1;
* which are used via the following masks.
*/
#define	N_STAB	0xe0  /* if any of these bits set, a symbolic debugging entry */
#define	N_PEXT	0x10  /* private external symbol bit */
#define	N_TYPE	0x0e  /* mask for the type bits */
#define	N_EXT	0x01  /* external symbol bit, set for external symbols */

/*
* Only symbolic debugging entries have some of the N_STAB bits set and if any
* of these bits are set then it is a symbolic debugging entry (a stab).  In
* which case then the values of the n_type field (the entire field) are given
* in <mach-o/stab.h>
*/

/*
* Values for N_TYPE bits of the n_type field.
*/
#define	N_UNDF	0x0		/* undefined, n_sect == NO_SECT */
#define	N_ABS	0x2		/* absolute, n_sect == NO_SECT */
#define	N_SECT	0xe		/* defined in section number n_sect */
#define	N_PBUD	0xc		/* prebound undefined (defined in a dylib) */
#define N_INDR	0xa		/* indirect */

/*
* If the type is N_INDR then the symbol is defined to be the same as another
* symbol.  In this case the n_value field is an index into the string table
* of the other symbol's name.  When the other symbol is defined then they both
* take on the defined type and value.
*/

/*
* If the type is N_SECT then the n_sect field contains an ordinal of the
* section the symbol is defined in.  The sections are numbered from 1 and
* refer to sections in order they appear in the load commands for the file
* they are in.  This means the same ordinal may very well refer to different
* sections in different files.
*
* The n_value field for all symbol table entries (including N_STAB's) gets
* updated by the link editor based on the value of it's n_sect field and where
* the section n_sect references gets relocated.  If the value of the n_sect
* field is NO_SECT then it's n_value field is not changed by the link editor.
*/
#define	NO_SECT		0	/* symbol is not in any section */
#define MAX_SECT	255	/* 1 thru 255 inclusive */

/*
* Common symbols are represented by undefined (N_UNDF) external (N_EXT) types
* who's values (n_value) are non-zero.  In which case the value of the n_value
* field is the size (in bytes) of the common symbol.  The n_sect field is set
* to NO_SECT.  The alignment of a common symbol may be set as a power of 2
* between 2^1 and 2^15 as part of the n_desc field using the macros below. If
* the alignment is not set (a value of zero) then natural alignment based on
* the size is used.
*/
#define GET_COMM_ALIGN(n_desc) (((n_desc) >> 8) & 0x0f)
#define SET_COMM_ALIGN(n_desc,align) \
    (n_desc) = (((n_desc) & 0xf0ff) | (((align) & 0x0f) << 8))

/*
* To support the lazy binding of undefined symbols in the dynamic link-editor,
* the undefined symbols in the symbol table (the nlist structures) are marked
* with the indication if the undefined reference is a lazy reference or
* non-lazy reference.  If both a non-lazy reference and a lazy reference is
* made to the same symbol the non-lazy reference takes precedence.  A reference
* is lazy only when all references to that symbol are made through a symbol
* pointer in a lazy symbol pointer section.
*
* The implementation of marking nlist structures in the symbol table for
* undefined symbols will be to use some of the bits of the n_desc field as a
* reference type.  The mask REFERENCE_TYPE will be applied to the n_desc field
* of an nlist structure for an undefined symbol to determine the type of
* undefined reference (lazy or non-lazy).
*
* The constants for the REFERENCE FLAGS are propagated to the reference table
* in a shared library file.  In that case the constant for a defined symbol,
* REFERENCE_FLAG_DEFINED, is also used.
*/
/* Reference type bits of the n_desc field of undefined symbols */
#define REFERENCE_TYPE				0x7
/* types of references */
#define REFERENCE_FLAG_UNDEFINED_NON_LAZY		0
#define REFERENCE_FLAG_UNDEFINED_LAZY			1
#define REFERENCE_FLAG_DEFINED				2
#define REFERENCE_FLAG_PRIVATE_DEFINED			3
#define REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY	4
#define REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY		5

/*
* To simplify stripping of objects that use are used with the dynamic link
* editor, the static link editor marks the symbols defined an object that are
* referenced by a dynamicly bound object (dynamic shared libraries, bundles).
* With this marking strip knows not to strip these symbols.
*/
#define REFERENCED_DYNAMICALLY	0x0010

/*
* For images created by the static link editor with the -twolevel_namespace
* option in effect the flags field of the mach header is marked with
* MH_TWOLEVEL.  And the binding of the undefined references of the image are
* determined by the static link editor.  Which library an undefined symbol is
* bound to is recorded by the static linker in the high 8 bits of the n_desc
* field using the SET_LIBRARY_ORDINAL macro below.  The ordinal recorded
* references the libraries listed in the Mach-O's LC_LOAD_DYLIB,
* LC_LOAD_WEAK_DYLIB, LC_REEXPORT_DYLIB, LC_LOAD_UPWARD_DYLIB, and
* LC_LAZY_LOAD_DYLIB, etc. load commands in the order they appear in the
* headers.   The library ordinals start from 1.
* For a dynamic library that is built as a two-level namespace image the
* undefined references from module defined in another use the same nlist struct
* an in that case SELF_LIBRARY_ORDINAL is used as the library ordinal.  For
* defined symbols in all images they also must have the library ordinal set to
* SELF_LIBRARY_ORDINAL.  The EXECUTABLE_ORDINAL refers to the executable
* image for references from plugins that refer to the executable that loads
* them.
*
* The DYNAMIC_LOOKUP_ORDINAL is for undefined symbols in a two-level namespace
* image that are looked up by the dynamic linker with flat namespace semantics.
* This ordinal was added as a feature in Mac OS X 10.3 by reducing the
* value of MAX_LIBRARY_ORDINAL by one.  So it is legal for existing binaries
* or binaries built with older tools to have 0xfe (254) dynamic libraries.  In
* this case the ordinal value 0xfe (254) must be treated as a library ordinal
* for compatibility.
*/
#define GET_LIBRARY_ORDINAL(n_desc) (((n_desc) >> 8) & 0xff)
#define SET_LIBRARY_ORDINAL(n_desc,ordinal) \
	(n_desc) = (((n_desc) & 0x00ff) | (((ordinal) & 0xff) << 8))
#define SELF_LIBRARY_ORDINAL 0x0
#define MAX_LIBRARY_ORDINAL 0xfd
#define DYNAMIC_LOOKUP_ORDINAL 0xfe
#define EXECUTABLE_ORDINAL 0xff

/*
* The bit 0x0020 of the n_desc field is used for two non-overlapping purposes
* and has two different symbolic names, N_NO_DEAD_STRIP and N_DESC_DISCARDED.
*/

/*
* The N_NO_DEAD_STRIP bit of the n_desc field only ever appears in a
* relocatable .o file (MH_OBJECT filetype). And is used to indicate to the
* static link editor it is never to dead strip the symbol.
*/
#define N_NO_DEAD_STRIP 0x0020 /* symbol is not to be dead stripped */

/*
* The N_DESC_DISCARDED bit of the n_desc field never appears in linked image.
* But is used in very rare cases by the dynamic link editor to mark an in
* memory symbol as discared and longer used for linking.
*/
#define N_DESC_DISCARDED 0x0020	/* symbol is discarded */

/*
* The N_WEAK_REF bit of the n_desc field indicates to the dynamic linker that
* the undefined symbol is allowed to be missing and is to have the address of
* zero when missing.
*/
#define N_WEAK_REF	0x0040 /* symbol is weak referenced */

/*
* The N_WEAK_DEF bit of the n_desc field indicates to the static and dynamic
* linkers that the symbol definition is weak, allowing a non-weak symbol to
* also be used which causes the weak definition to be discared.  Currently this
* is only supported for symbols in coalesed sections.
*/
#define N_WEAK_DEF	0x0080 /* coalesed symbol is a weak definition */

/*
* The N_REF_TO_WEAK bit of the n_desc field indicates to the dynamic linker
* that the undefined symbol should be resolved using flat namespace searching.
*/
#define	N_REF_TO_WEAK	0x0080 /* reference to a weak symbol */

/*
* The N_ARM_THUMB_DEF bit of the n_desc field indicates that the symbol is
* a defintion of a Thumb function.
*/
#define N_ARM_THUMB_DEF	0x0008 /* symbol is a Thumb function (ARM) */

/*
* The N_SYMBOL_RESOLVER bit of the n_desc field indicates that the
* that the function is actually a resolver function and should
* be called to get the address of the real function to use.
* This bit is only available in .o files (MH_OBJECT filetype)
*/
#define N_SYMBOL_RESOLVER  0x0100 

/*
* The N_ALT_ENTRY bit of the n_desc field indicates that the
* symbol is pinned to the previous content.
*/
#define N_ALT_ENTRY 0x0200

/*
* Relocations for x86_64 are a bit different than for other architectures in
* Mach-O: Scattered relocations are not used.  Almost all relocations produced
* by the compiler are external relocations.  An external relocation has the
* r_extern bit set to 1 and the r_symbolnum field contains the symbol table
* index of the target label.
*
* When the assembler is generating relocations, if the target label is a local
* label (begins with 'L'), then the previous non-local label in the same
* section is used as the target of the external relocation.  An addend is used
* with the distance from that non-local label to the target label.  Only when
* there is no previous non-local label in the section is an internal
* relocation used.
*
* The addend (i.e. the 4 in _foo+4) is encoded in the instruction (Mach-O does
* not have RELA relocations).  For PC-relative relocations, the addend is
* stored directly in the instruction.  This is different from other Mach-O
* architectures, which encode the addend minus the current section offset.
*
* The relocation types are:
*
* 	X86_64_RELOC_UNSIGNED	// for absolute addresses
* 	X86_64_RELOC_SIGNED		// for signed 32-bit displacement
* 	X86_64_RELOC_BRANCH		// a CALL/JMP instruction with 32-bit displacement
* 	X86_64_RELOC_GOT_LOAD	// a MOVQ load of a GOT entry
* 	X86_64_RELOC_GOT		// other GOT references
* 	X86_64_RELOC_SUBTRACTOR	// must be followed by a X86_64_RELOC_UNSIGNED
*
* The following are sample assembly instructions, followed by the relocation
* and section content they generate in an object file:
*
* 	call _foo
* 		r_type=X86_64_RELOC_BRANCH, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		E8 00 00 00 00
*
* 	call _foo+4
* 		r_type=X86_64_RELOC_BRANCH, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		E8 04 00 00 00
*
* 	movq _foo@GOTPCREL(%rip), %rax
* 		r_type=X86_64_RELOC_GOT_LOAD, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		48 8B 05 00 00 00 00
*
* 	pushq _foo@GOTPCREL(%rip)
* 		r_type=X86_64_RELOC_GOT, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		FF 35 00 00 00 00
*
* 	movl _foo(%rip), %eax
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		8B 05 00 00 00 00
*
* 	movl _foo+4(%rip), %eax
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		8B 05 04 00 00 00
*
* 	movb  $0x12, _foo(%rip)
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		C6 05 FF FF FF FF 12
*
* 	movl  $0x12345678, _foo(%rip)
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_foo
* 		C7 05 FC FF FF FF 78 56 34 12
*
* 	.quad _foo
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		00 00 00 00 00 00 00 00
*
* 	.quad _foo+4
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		04 00 00 00 00 00 00 00
*
* 	.quad _foo - _bar
* 		r_type=X86_64_RELOC_SUBTRACTOR, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_bar
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		00 00 00 00 00 00 00 00
*
* 	.quad _foo - _bar + 4
* 		r_type=X86_64_RELOC_SUBTRACTOR, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_bar
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		04 00 00 00 00 00 00 00
*
* 	.long _foo - _bar
* 		r_type=X86_64_RELOC_SUBTRACTOR, r_length=2, r_extern=1, r_pcrel=0, r_symbolnum=_bar
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=2, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		00 00 00 00
*
* 	lea L1(%rip), %rax
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=1, r_pcrel=1, r_symbolnum=_prev
* 		48 8d 05 12 00 00 00
* 		// assumes _prev is the first non-local label 0x12 bytes before L1
*
* 	lea L0(%rip), %rax
* 		r_type=X86_64_RELOC_SIGNED, r_length=2, r_extern=0, r_pcrel=1, r_symbolnum=3
* 		48 8d 05 56 00 00 00
*		// assumes L0 is in third section and there is no previous non-local label.
*		// The rip-relative-offset of 0x00000056 is L0-address_of_next_instruction.
*		// address_of_next_instruction is the address of the relocation + 4.
*
*     add     $6,L0(%rip)
*             r_type=X86_64_RELOC_SIGNED_1, r_length=2, r_extern=0, r_pcrel=1, r_symbolnum=3
*		83 05 18 00 00 00 06
*		// assumes L0 is in third section and there is no previous non-local label.
*		// The rip-relative-offset of 0x00000018 is L0-address_of_next_instruction.
*		// address_of_next_instruction is the address of the relocation + 4 + 1.
*		// The +1 comes from SIGNED_1.  This is used because the relocation is not
*		// at the end of the instruction.
*
* 	.quad L1
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_prev
* 		12 00 00 00 00 00 00 00
* 		// assumes _prev is the first non-local label 0x12 bytes before L1
*
* 	.quad L0
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=0, r_pcrel=0, r_symbolnum=3
* 		56 00 00 00 00 00 00 00
* 		// assumes L0 is in third section, has an address of 0x00000056 in .o
* 		// file, and there is no previous non-local label
*
* 	.quad _foo - .
* 		r_type=X86_64_RELOC_SUBTRACTOR, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_prev
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		EE FF FF FF FF FF FF FF
* 		// assumes _prev is the first non-local label 0x12 bytes before this
* 		// .quad
*
* 	.quad _foo - L1
* 		r_type=X86_64_RELOC_SUBTRACTOR, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_prev
* 		r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_extern=1, r_pcrel=0, r_symbolnum=_foo
* 		EE FF FF FF FF FF FF FF
* 		// assumes _prev is the first non-local label 0x12 bytes before L1
*
* 	.quad L1 - _prev
* 		// No relocations.  This is an assembly time constant.
* 		12 00 00 00 00 00 00 00
* 		// assumes _prev is the first non-local label 0x12 bytes before L1
*
*
*
* In final linked images, there are only two valid relocation kinds:
*
*     r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_pcrel=0, r_extern=1, r_symbolnum=sym_index
*	This tells dyld to add the address of a symbol to a pointer sized (8-byte)
*  piece of data (i.e on disk the 8-byte piece of data contains the addend). The
*  r_symbolnum contains the index into the symbol table of the target symbol.
*
*     r_type=X86_64_RELOC_UNSIGNED, r_length=3, r_pcrel=0, r_extern=0, r_symbolnum=0
* This tells dyld to adjust the pointer sized (8-byte) piece of data by the amount
* the containing image was loaded from its base address (e.g. slide).
*
*/
enum reloc_type_x86_64
{
	X86_64_RELOC_UNSIGNED,		// for absolute addresses
	X86_64_RELOC_SIGNED,		// for signed 32-bit displacement
	X86_64_RELOC_BRANCH,		// a CALL/JMP instruction with 32-bit displacement
	X86_64_RELOC_GOT_LOAD,		// a MOVQ load of a GOT entry
	X86_64_RELOC_GOT,			// other GOT references
	X86_64_RELOC_SUBTRACTOR,	// must be followed by a X86_64_RELOC_UNSIGNED
	X86_64_RELOC_SIGNED_1,		// for signed 32-bit displacement with a -1 addend
	X86_64_RELOC_SIGNED_2,		// for signed 32-bit displacement with a -2 addend
	X86_64_RELOC_SIGNED_4,		// for signed 32-bit displacement with a -4 addend
	X86_64_RELOC_TLV,		// for thread local variables
};

struct relocation_info { int32_t r_address; uint32_t r_symbolnum : 24, r_pcrel : 1, r_length : 2, r_extern : 1, r_type : 4; };

#endif /* End of MACHO64SPEC_H */

