ld64-77.1.tar.gz

[apple/ld64.git] / src / MachOReaderRelocatable.hpp

/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
 *
 * Copyright (c) 2005-2007 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.
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 * @APPLE_LICENSE_HEADER_END@
 */

#ifndef __OBJECT_FILE_MACH_O__
#define __OBJECT_FILE_MACH_O__

#include <stdint.h>
#include <math.h>
#include <unistd.h>
#include <sys/param.h>
#include <mach-o/ppc/reloc.h>
#include <mach-o/stab.h>
#include <mach-o/x86_64/reloc.h>
#ifndef S_ATTR_DEBUG
 #define S_ATTR_DEBUG 0x02000000
#endif

#include <vector>
#include <set>
#include <algorithm>

#include "MachOFileAbstraction.hpp"
#include "Architectures.hpp"
#include "ObjectFile.h"
#include "dwarf2.h"
#include "debugline.h"


//
//
//	To implement architecture xxx, you must write template specializations for the following six methods:
//			Reader<xxx>::validFile()
//			Reader<xxx>::validSectionType()
//			Reader<xxx>::addRelocReference()
//			Reference<xxx>::getDescription()
//
//



extern  __attribute__((noreturn)) void throwf(const char* format, ...);

namespace mach_o {
namespace relocatable {



class ReferenceSorter
{
public:
	bool operator()(const ObjectFile::Reference* left, const ObjectFile::Reference* right)
	{
		return ( left->getFixUpOffset() < right->getFixUpOffset() );
	}
};


// forward reference
template <typename A> class Reader;

struct AtomAndOffset
{
						AtomAndOffset(ObjectFile::Atom* a=NULL) : atom(a), offset(0) {}
						AtomAndOffset(ObjectFile::Atom* a, uint32_t off) : atom(a), offset(off) {}
	ObjectFile::Atom*	atom;
	uint32_t			offset;
};


template <typename A>
class Reference : public ObjectFile::Reference
{
public:
	typedef typename A::P						P;
	typedef typename A::P::uint_t				pint_t;
	typedef typename A::ReferenceKinds			Kinds;

							Reference(Kinds kind, const AtomAndOffset& at, const AtomAndOffset& toTarget);
							Reference(Kinds kind, const AtomAndOffset& at, const AtomAndOffset& fromTarget, const AtomAndOffset& toTarget);
							Reference(Kinds kind, const AtomAndOffset& at, const char* toName, uint32_t toOffset);

	virtual					~Reference() {}


	virtual ObjectFile::Reference::TargetBinding	getTargetBinding() const;
	virtual ObjectFile::Reference::TargetBinding	getFromTargetBinding() const;
	virtual uint8_t			getKind() const									{ return (uint8_t)fKind; }
	virtual uint64_t		getFixUpOffset() const							{ return fFixUpOffsetInSrc; }
	virtual const char*		getTargetName() const							{ return (fToTargetName != NULL) ? fToTargetName : fToTarget.atom->getName(); }
	virtual ObjectFile::Atom& getTarget() const								{ return *fToTarget.atom; }
	virtual uint64_t		getTargetOffset() const							{ return (int64_t)((int32_t)fToTarget.offset); }
	virtual ObjectFile::Atom& getFromTarget() const							{ return *fFromTarget.atom; }
	virtual const char*		getFromTargetName() const						{ return (fFromTargetName != NULL) ? fFromTargetName : fFromTarget.atom->getName(); }
	virtual void			setTarget(ObjectFile::Atom& target, uint64_t offset)	{ fToTarget.atom = &target; fToTarget.offset = offset; }
	virtual void			setToTargetOffset(uint64_t offset)				{ fToTarget.offset = offset; }
	virtual void			setFromTarget(ObjectFile::Atom& target)			{ fFromTarget.atom = &target; }
	virtual void			setFromTargetName(const char* name)				{ fFromTargetName = name; }
	virtual void			setFromTargetOffset(uint64_t offset)			{ fFromTarget.offset = offset; }
	virtual const char*		getDescription() const;
	virtual uint64_t		getFromTargetOffset() const						{ return fFromTarget.offset; }

	static bool				fgForFinalLinkedImage;

private:
	pint_t					fFixUpOffsetInSrc;
	AtomAndOffset			fToTarget;
	AtomAndOffset			fFromTarget;
	const char*				fToTargetName;
	const char*				fFromTargetName;
	Kinds					fKind;
	
};

template <typename A> bool Reference<A>::fgForFinalLinkedImage = true;

template <typename A>
Reference<A>::Reference(Kinds kind, const AtomAndOffset& at, const AtomAndOffset& toTarget)
 : fFixUpOffsetInSrc(at.offset), fToTarget(toTarget), fToTargetName(NULL), fFromTargetName(NULL),
    fKind(kind)
{
	// make reference a by-name unless:
	// - the reference type is only used with direct references
	// - the target is translation unit scoped
	// - the target kind is not regular (is weak or tentative)
	if ( (kind != A::kNoFixUp) && (kind != A::kFollowOn) 
		&& (toTarget.atom->getScope() != ObjectFile::Atom::scopeTranslationUnit) 
		&& (toTarget.atom->getDefinitionKind() != ObjectFile::Atom::kRegularDefinition) ) {
		fToTargetName = toTarget.atom->getName();
		//fprintf(stderr, "Reference(): changing to by-name %p %s, target scope=%d, target section=%s\n", toTarget.atom, fToTargetName, toTarget.atom->getScope(), toTarget.atom->getSectionName());
		fToTarget.atom = NULL;
	}
	((class BaseAtom*)at.atom)->addReference(this);
	//fprintf(stderr, "Reference(): %p fToTarget<%s, %08X>\n", this, (fToTarget.atom != NULL) ? fToTarget.atom->getDisplayName() : fToTargetName , fToTarget.offset);
}

template <typename A>
Reference<A>::Reference(Kinds kind, const AtomAndOffset& at, const AtomAndOffset& fromTarget, const AtomAndOffset& toTarget)
 : fFixUpOffsetInSrc(at.offset), fToTarget(toTarget), fFromTarget(fromTarget),
   fToTargetName(NULL), fFromTargetName(NULL), fKind(kind)
{
	// make reference a by-name where needed
	if ( (kind != A::kNoFixUp) && (kind != A::kFollowOn) 
		&& (toTarget.atom->getScope() != ObjectFile::Atom::scopeTranslationUnit)
		&& (toTarget.atom->getDefinitionKind() != ObjectFile::Atom::kRegularDefinition) 
		&& (toTarget.atom != at.atom) ) {
			fToTargetName = toTarget.atom->getName();
			fToTarget.atom = NULL;
	}
	((class BaseAtom*)at.atom)->addReference(this);
	//fprintf(stderr, "Reference(): %p kind=%d, fToTarget<%s, %08X>, fromTarget<%s, %08X>\n", this, kind,
	//	 this->getTargetName(), fToTarget.offset, this->getFromTargetName(), fromTarget.offset);
}

template <typename A>
Reference<A>::Reference(Kinds kind, const AtomAndOffset& at, const char* toName, uint32_t toOffset)
 : fFixUpOffsetInSrc(at.offset),
   fToTargetName(toName), fFromTargetName(NULL), fKind(kind)
{
	fToTarget.offset = toOffset;
	((class BaseAtom*)at.atom)->addReference(this);
}

template <typename A>
ObjectFile::Reference::TargetBinding Reference<A>::getTargetBinding() const
{
	if ( fgForFinalLinkedImage ) {
		if ( (fKind == A::kDtraceProbe) || (fKind == A::kDtraceProbeSite) || (fKind == A::kDtraceIsEnabledSite) || (fKind == A::kDtraceTypeReference) )
			return ObjectFile::Reference::kDontBind;
	}
	if ( fToTarget.atom == NULL ) 
		return ObjectFile::Reference::kUnboundByName;
	if ( fToTargetName == NULL ) 
		return ObjectFile::Reference::kBoundDirectly;
	else
		return ObjectFile::Reference::kBoundByName;
}

template <typename A>
ObjectFile::Reference::TargetBinding Reference<A>::getFromTargetBinding() const
{
	if ( fFromTarget.atom == NULL ) {
		if ( fFromTargetName == NULL ) 
			return ObjectFile::Reference::kDontBind;
		else
			return ObjectFile::Reference::kUnboundByName;
	}
	else {
		if ( fFromTargetName == NULL ) 
			return ObjectFile::Reference::kBoundDirectly;
		else
			return ObjectFile::Reference::kBoundByName;
	}
}



template <typename A>
class Segment : public ObjectFile::Segment
{
public:
								Segment(const macho_section<typename A::P>* sect);
	virtual const char*			getName() const						{ return fSection->segname(); }
	virtual bool				isContentReadable() const			{ return true; }
	virtual bool				isContentWritable() const			{ return fWritable; }
	virtual bool				isContentExecutable() const			{ return fExecutable; }
private:
	const macho_section<typename A::P>*		fSection;
	bool									fWritable;
	bool									fExecutable;
};

template <typename A>
Segment<A>::Segment(const macho_section<typename A::P>* sect) 
 :	fSection(sect), fWritable(true),  fExecutable(false) 
{
	if ( strcmp(fSection->segname(), "__TEXT") == 0 ) {
		fWritable = false;
		fExecutable = true;
	}
	else if ( strcmp(fSection->segname(), "__IMPORT") == 0 ) {
		fWritable = true;
		fExecutable = true;
	}
}


class DataSegment : public ObjectFile::Segment
{
public:
	virtual const char*			getName() const						{ return "__DATA"; }
	virtual bool				isContentReadable() const			{ return true; }
	virtual bool				isContentWritable() const			{ return true; }
	virtual bool				isContentExecutable() const			{ return false; }

	static DataSegment			fgSingleton;
};

DataSegment DataSegment::fgSingleton;

class LinkEditSegment : public ObjectFile::Segment
{
public:
	virtual const char*			getName() const						{ return "__LINKEDIT"; }
	virtual bool				isContentReadable() const			{ return true; }
	virtual bool				isContentWritable() const			{ return false; }
	virtual bool				isContentExecutable() const			{ return false; }

	static LinkEditSegment			fgSingleton;
};

LinkEditSegment LinkEditSegment::fgSingleton;

class BaseAtom : public ObjectFile::Atom
{
public:
												BaseAtom() : fStabsStartIndex(0), fStabsCount(0) {}

	virtual void								setSize(uint64_t size)	= 0;
	virtual void								addReference(ObjectFile::Reference* ref) = 0;
	virtual void								sortReferences() = 0;
	virtual void								addLineInfo(const ObjectFile::LineInfo& info) = 0;
	virtual uint64_t							getObjectAddress() const = 0;
	virtual uint32_t							getOrdinal() const { return fOrdinal; }
	virtual void								setOrdinal(uint32_t value) { fOrdinal = value; }
	virtual const void*							getSectionRecord() const = 0;
	virtual bool								isAlias() const { return false; }

	uint32_t									fStabsStartIndex;
	uint32_t									fStabsCount;
	uint32_t									fOrdinal;
};

class BaseAtomSorter
{
public:
	bool operator()(const class BaseAtom* left, const class BaseAtom* right)  {
		if ( left == right )
			return false;
		uint64_t leftAddr  =  left->getObjectAddress();
		uint64_t rightAddr = right->getObjectAddress();
		if ( leftAddr < rightAddr ) {
			return true;
		}
		else if ( leftAddr > rightAddr ) {
			return false;
		}
		else {
			// if they have same address, one might be the end of a section and the other the start of the next section
			const void* leftSection  =  left->getSectionRecord();
			const void* rightSection =  right->getSectionRecord();
			if ( leftSection != rightSection ) {
				return ( leftSection < rightSection );
			}
			// if they have same address and section, one might be an alias
			bool leftAlias  = left->isAlias();
			bool rightAlias = right->isAlias();
			if ( leftAlias && rightAlias ) {
				// sort multiple aliases for same address first by scope
				ObjectFile::Atom::Scope	leftScope  = left->getScope();
				ObjectFile::Atom::Scope	rightScope = right->getScope();
				if ( leftScope != rightScope ) {
					return ( leftScope < rightScope );
				}
				// sort multiple aliases for same address then by name
				return ( strcmp(left->getName(), right->getName()) < 0 );
			}
			else if ( leftAlias ) {
				return true;
			}
			else if ( rightAlias ) {
				return false;
			}
			else {
				// they must be tentative defintions
				switch ( left->getDefinitionKind() ) {
					case ObjectFile::Atom::kTentativeDefinition:
						// sort tentative definitions by name
						return ( strcmp(left->getName(), right->getName()) < 0 );
					case ObjectFile::Atom::kAbsoluteSymbol:
						// sort absolute symbols with same address by name
						return ( strcmp(left->getName(), right->getName()) < 0 );
					default:
						// hack for rdar://problem/5102873
						if ( !left->isZeroFill() || !right->isZeroFill() )
							fprintf(stderr, "ld: atom sorting error for %s and %s in %s\n", left->getDisplayName(), right->getDisplayName(), left->getFile()->getPath());
						break;
				}
			}
		}
		return false;
	}
};


//
// A SymbolAtom represents a chunk of a mach-o object file that has a symbol table entry
// pointing to it.  A C function or global variable is represented by one of these atoms.
//
//
template <typename A>
class SymbolAtom : public BaseAtom
{
public:
	virtual ObjectFile::Reader*					getFile() const					{ return &fOwner; }
	virtual bool								getTranslationUnitSource(const char** dir, const char** name) const
																				{ return fOwner.getTranslationUnitSource(dir, name); }
	virtual const char*							getName() const					{ return &fOwner.fStrings[fSymbol->n_strx()]; }
	virtual const char*							getDisplayName() const			{ return getName(); }
	virtual ObjectFile::Atom::Scope				getScope() const				{ return fScope; }
	virtual ObjectFile::Atom::DefinitionKind	getDefinitionKind() const		{ return ((fSymbol->n_desc() & N_WEAK_DEF) != 0)
																						? ObjectFile::Atom::kWeakDefinition : ObjectFile::Atom::kRegularDefinition; }
	virtual SymbolTableInclusion				getSymbolTableInclusion() const	{ return fSymbolTableInclusion; }
	virtual	bool								dontDeadStrip() const;
	virtual bool								isZeroFill() const				{ return ((fSection->flags() & SECTION_TYPE) == S_ZEROFILL); }
	virtual uint64_t							getSize() const					{ return fSize; }
	virtual std::vector<ObjectFile::Reference*>&  getReferences() const			{ return (std::vector<ObjectFile::Reference*>&)(fReferences); }
	virtual bool								mustRemainInSection() const		{ return true; }
	virtual const char*							getSectionName() const;
	virtual Segment<A>&							getSegment() const				{ return *fSegment; }
	virtual ObjectFile::Atom&					getFollowOnAtom() const;
	virtual std::vector<ObjectFile::LineInfo>*	getLineInfo() const				{ return (std::vector<ObjectFile::LineInfo>*)&fLineInfo; }
	virtual ObjectFile::Alignment				getAlignment() const			{ return fAlignment; }
	virtual void								copyRawContent(uint8_t buffer[]) const;
	virtual void								setScope(ObjectFile::Atom::Scope newScope)		{ fScope = newScope; }
	virtual void								setSize(uint64_t size);
	virtual void								addReference(ObjectFile::Reference* ref) { fReferences.push_back((Reference<A>*)ref); }
	virtual void								sortReferences() { std::sort(fReferences.begin(), fReferences.end(), ReferenceSorter()); }
	virtual void								addLineInfo(const  ObjectFile::LineInfo& info)	{ fLineInfo.push_back(info); }
	virtual uint64_t							getObjectAddress() const 		{ return fAddress; }
	virtual const void*							getSectionRecord() const		{ return (const void*)fSection; }

protected:
	typedef typename A::P						P;
	typedef typename A::P::E					E;
	typedef typename A::P::uint_t				pint_t;
	typedef typename A::ReferenceKinds			Kinds;
	typedef typename std::vector<Reference<A>*>			ReferenceVector;
	typedef typename ReferenceVector::iterator			ReferenceVectorIterator;		// seems to help C++ parser
	typedef typename ReferenceVector::const_iterator	ReferenceVectorConstIterator;	// seems to help C++ parser
	friend class Reader<A>;

											SymbolAtom(Reader<A>&, const macho_nlist<P>*, const macho_section<P>*);
	virtual									~SymbolAtom() {}

	Reader<A>&									fOwner;
	const macho_nlist<P>*						fSymbol;
	pint_t										fAddress;
	pint_t										fSize;
	const macho_section<P>*						fSection;
	Segment<A>*									fSegment;
	ReferenceVector								fReferences;
	std::vector<ObjectFile::LineInfo>			fLineInfo;
	ObjectFile::Atom::Scope						fScope;
	SymbolTableInclusion						fSymbolTableInclusion;
	ObjectFile::Alignment						fAlignment;
};


template <typename A>
SymbolAtom<A>::SymbolAtom(Reader<A>& owner, const macho_nlist<P>* symbol, const macho_section<P>* section)
 : fOwner(owner), fSymbol(symbol), fAddress(0), fSize(0), fSection(section), fSegment(NULL), fAlignment(0)
{
	uint8_t type =  symbol->n_type();
	if ( (type & N_EXT) == 0 )
		fScope = ObjectFile::Atom::scopeTranslationUnit;
	else if ( (type & N_PEXT) != 0 )
		fScope = ObjectFile::Atom::scopeLinkageUnit;
	else
		fScope = ObjectFile::Atom::scopeGlobal;
	if ( (type & N_TYPE) == N_SECT ) {
		// real definition
 		fSegment = new Segment<A>(fSection);
		fAddress = fSymbol->n_value();
	}	
	else {
		printf("unknown symbol type: %d\n", type);
	}
	//fprintf(stderr, "SymbolAtom(%p) %s fAddress=0x%X\n", this, this->getDisplayName(), (uint32_t)fAddress);
	// support for .o files built with old ld64
	if ( (fSymbol->n_desc() & N_WEAK_DEF) && (strcmp(fSection->sectname(),"__picsymbolstub1__TEXT") == 0) ) {
		const char* name = this->getName();
		const int nameLen = strlen(name);
		if ( (nameLen > 6) && strcmp(&name[nameLen-5], "$stub") == 0 ) {
			// switch symbol to point at name that does not have trailing $stub
			char correctName[nameLen];
			strncpy(correctName, name, nameLen-5);
			correctName[nameLen-5] = '\0';
			const macho_nlist<P>* symbolsStart = fOwner.fSymbols;
			const macho_nlist<P>* symbolsEnd = &symbolsStart[fOwner.fSymbolCount];
			for(const macho_nlist<P>* s = symbolsStart; s < symbolsEnd; ++s) {
				if ( strcmp(&fOwner.fStrings[s->n_strx()], correctName) == 0 ) {
					fSymbol = s;
					break;
				}
			}
		}
	}
	// support for labeled stubs
	switch ( section->flags() & SECTION_TYPE ) {
		case S_SYMBOL_STUBS:
			setSize(section->reserved2());
			break;
		case S_LAZY_SYMBOL_POINTERS:
		case S_NON_LAZY_SYMBOL_POINTERS:
			setSize(sizeof(pint_t));
			break;
		case S_4BYTE_LITERALS:
			setSize(4);
			break;
		case S_8BYTE_LITERALS:
			setSize(8);
			break;
		case S_16BYTE_LITERALS:
			setSize(16);
			break;
		case S_CSTRING_LITERALS:
			setSize(strlen((char*)(fOwner.fHeader) + section->offset() + fAddress - section->addr()) + 1);
			break;
		case S_REGULAR:
		case S_ZEROFILL:
		case S_COALESCED:
			// size calculate later after next atom is found
			break;
	}
	
	// compute whether this atom needs to be in symbol table
	if ( (fSymbol->n_desc() & REFERENCED_DYNAMICALLY) != 0) {
		fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableInAndNeverStrip;
	}
	else if (  fOwner.fOptions.fForFinalLinkedImage 
			&& ((section->flags() & SECTION_TYPE) == S_COALESCED) 
			&& ((section->flags() & S_ATTR_NO_TOC) == S_ATTR_NO_TOC) 
			&& ((section->flags() & S_ATTR_STRIP_STATIC_SYMS) == S_ATTR_STRIP_STATIC_SYMS) 
			&& (strcmp(section->sectname(), "__eh_frame") == 0) ) {
		// .eh symbols exist so the linker can associate them with functions
		// removing them from final linked images is a big space savings rdar://problem/4180168
		fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableNotIn;
	}
	else if (  fOwner.fOptions.fForFinalLinkedImage 
			&& ((section->flags() & SECTION_TYPE) == S_REGULAR) 
			&& (strncmp(section->sectname(), "__gcc_except_tab", 16) == 0) 
			&& (strncmp(this->getName(),     "GCC_except_table", 16) == 0) ) {
		// GCC_except_table* symbols don't need to exist in final linked image
		fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableNotIn;
	}
	else if ( fOwner.fOptions.fForFinalLinkedImage && !fOwner.fOptions.fForStatic && (fOwner.fStrings[fSymbol->n_strx()] == 'l') ) {
		// labels beginning with a lowercase ell are automatically removed in final linked images <rdar://problem/4571042>
		// xnu code base uses a lot of asesembly labels that start with 'l', don't strip those (static executable)
		fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableNotIn;
	}
	else {
		fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableIn;
	}
	// compute alignment
	fAlignment = ObjectFile::Alignment(fSection->align(), fAddress % (1 << fSection->align()));
	
	// work around malformed icc generated .o files  <rdar://problem/5349847>
	// if section starts with a symbol and that symbol address does not match section alignment, then force it to
	if ( (section->addr() == fAddress) && (fAlignment.modulus != 0) )
		fAlignment.modulus = 0;
}

template <typename A>
bool SymbolAtom<A>::dontDeadStrip() const
{
	// the symbol can have a no-dead-strip bit
	if ( (fSymbol->n_desc() & (N_NO_DEAD_STRIP|REFERENCED_DYNAMICALLY)) != 0 )
		return true;
	// or the section can have a no-dead-strip bit
	return ( fSection->flags() & S_ATTR_NO_DEAD_STRIP );
}


template <typename A>
const char*	SymbolAtom<A>::getSectionName() const
{
	if ( fOwner.fOptions.fForFinalLinkedImage && (strcmp(fSection->sectname(), "__textcoal_nt") == 0) )
		return "__text";
	
	if ( strlen(fSection->sectname()) > 15 ) {
		static char temp[18];
		strncpy(temp, fSection->sectname(), 16);
		temp[17] = '\0';
		return temp;
	}
	return fSection->sectname();
}

template <typename A>
ObjectFile::Atom& SymbolAtom<A>::getFollowOnAtom() const
{
	for (ReferenceVectorConstIterator it=fReferences.begin(); it != fReferences.end(); it++) {
		Reference<A>* ref = *it;
		if ( ref->getKind() == A::kFollowOn )
			return ref->getTarget();
	}
	return *((ObjectFile::Atom*)NULL);
}


class Beyond
{
public:
	Beyond(uint64_t offset) : fOffset(offset) {}
	bool operator()(ObjectFile::Reference* ref) const {
		return ( ref->getFixUpOffset() >= fOffset );
	}
private:
	uint64_t fOffset;
};


template <typename A>
void SymbolAtom<A>::setSize(uint64_t size)
{
	// when resizing, any references beyond the new size are tossed
	if ( (fSize != 0) && (fReferences.size() > 0) ) 
		fReferences.erase(std::remove_if(fReferences.begin(), fReferences.end(), Beyond(size)), fReferences.end());
	// set new size
	fSize = size;
}

template <typename A>
void SymbolAtom<A>::copyRawContent(uint8_t buffer[]) const
{
	// copy base bytes
	if ( isZeroFill() )
		bzero(buffer, fSize);
	else {
		uint32_t fileOffset = fSection->offset() - fSection->addr() + fAddress;
		memcpy(buffer, (char*)(fOwner.fHeader)+fileOffset, fSize);
	}
}

//
// A SymbolAliasAtom represents an alternate name for a SymbolAtom
//
//
template <typename A>
class SymbolAliasAtom : public BaseAtom
{
public:
	virtual ObjectFile::Reader*					getFile() const					{ return fAliasOf.getFile(); }
	virtual bool								getTranslationUnitSource(const char** dir, const char** name) const
																				{ return fAliasOf.getTranslationUnitSource(dir, name); }
	virtual const char*							getName() const					{ return fName; }
	virtual const char*							getDisplayName() const			{ return fName; }
	virtual ObjectFile::Atom::Scope				getScope() const				{ return fScope; }
	virtual ObjectFile::Atom::DefinitionKind	getDefinitionKind() const		{ return fAliasOf.getDefinitionKind(); }
	virtual SymbolTableInclusion				getSymbolTableInclusion() const	{ return fAliasOf.getSymbolTableInclusion(); }
	virtual	bool								dontDeadStrip() const			{ return fDontDeadStrip; }
	virtual bool								isZeroFill() const				{ return fAliasOf.isZeroFill(); }
	virtual uint64_t							getSize() const					{ return 0; }
	virtual std::vector<ObjectFile::Reference*>&  getReferences() const			{ return (std::vector<ObjectFile::Reference*>&)(fReferences); }
	virtual bool								mustRemainInSection() const		{ return true; }
	virtual const char*							getSectionName() const			{ return fAliasOf.getSectionName(); }
	virtual Segment<A>&							getSegment() const				{ return (Segment<A>&)fAliasOf.getSegment(); }
	virtual ObjectFile::Atom&					getFollowOnAtom() const			{ return (ObjectFile::Atom&)fAliasOf; }
	virtual std::vector<ObjectFile::LineInfo>*	getLineInfo() const				{ return NULL; }
	virtual ObjectFile::Alignment				getAlignment() const			{ return  fAliasOf.getAlignment(); }
	virtual void								copyRawContent(uint8_t buffer[]) const {}
	virtual void								setScope(ObjectFile::Atom::Scope newScope)		{ fScope = newScope; }
	virtual void								setSize(uint64_t size)			{  }
	virtual void								addReference(ObjectFile::Reference* ref) { fReferences.push_back((Reference<A>*)ref); }
	virtual void								sortReferences() { std::sort(fReferences.begin(), fReferences.end(), ReferenceSorter()); }
	virtual void								addLineInfo(const  ObjectFile::LineInfo& info)	{  }
	virtual uint64_t							getObjectAddress() const		{ return fAliasOf.getObjectAddress(); }
	virtual const void*							getSectionRecord() const		{ return fAliasOf.getSectionRecord(); }
	virtual bool								isAlias() const					{ return true; }

protected:
	typedef typename A::P						P;
	typedef typename std::vector<Reference<A>*>			ReferenceVector;
	typedef typename ReferenceVector::iterator			ReferenceVectorIterator;		// seems to help C++ parser
	typedef typename ReferenceVector::const_iterator	ReferenceVectorConstIterator;	// seems to help C++ parser
	friend class Reader<A>;

											SymbolAliasAtom(const char* name, const macho_nlist<P>*, const BaseAtom& );
	virtual									~SymbolAliasAtom() {}

	const char*									fName;
	const BaseAtom&								fAliasOf;
	ObjectFile::Atom::Scope						fScope;
	bool										fDontDeadStrip;
	ReferenceVector								fReferences;
};


template <typename A>
SymbolAliasAtom<A>::SymbolAliasAtom(const char* name, const macho_nlist<P>* symbol, const BaseAtom& aliasOf)
 : fName(name), fAliasOf(aliasOf)
{
	//fprintf(stderr, "SymbolAliasAtom(%p) %s\n", this, name);
	if ( symbol != NULL ) {
		uint8_t type =  symbol->n_type();
		if ( (type & N_EXT) == 0 )
			fScope = ObjectFile::Atom::scopeTranslationUnit;
		else if ( (type & N_PEXT) != 0 )
			fScope = ObjectFile::Atom::scopeLinkageUnit;
		else
			fScope = ObjectFile::Atom::scopeGlobal;
		fDontDeadStrip = ((symbol->n_desc() & (N_NO_DEAD_STRIP|REFERENCED_DYNAMICALLY)) != 0);
	}
	else {
		// aliases defined on the command line are initially global scope
		fScope = ObjectFile::Atom::scopeGlobal;
		fDontDeadStrip = false;
	}
	// add follow-on reference to real atom	
	new Reference<A>(A::kFollowOn, AtomAndOffset(this), AtomAndOffset((ObjectFile::Atom*)&aliasOf));
}


//
// A TentativeAtom represents a C "common" or "tentative" defintion of data.
// For instance, "int foo;" is neither a declaration or a definition and
// is represented by a TentativeAtom.
//
template <typename A>
class TentativeAtom : public BaseAtom
{
public:
	virtual ObjectFile::Reader*					getFile() const					{ return &fOwner; }
	virtual bool								getTranslationUnitSource(const char** dir, const char** name) const
																				{ return fOwner.getTranslationUnitSource(dir, name); }
	virtual const char*							getName() const					{ return &fOwner.fStrings[fSymbol->n_strx()]; }
	virtual const char*							getDisplayName() const			{ return getName(); }
	virtual ObjectFile::Atom::Scope				getScope() const				{ return fScope; }
	virtual ObjectFile::Atom::DefinitionKind	getDefinitionKind() const		{ return ObjectFile::Atom::kTentativeDefinition; }
	virtual bool								isZeroFill() const				{ return true; }
	virtual SymbolTableInclusion				getSymbolTableInclusion() const	{ return ((fSymbol->n_desc() & REFERENCED_DYNAMICALLY) != 0)
																						? ObjectFile::Atom::kSymbolTableInAndNeverStrip : ObjectFile::Atom::kSymbolTableIn; }
	virtual	bool								dontDeadStrip() const			{ return ((fSymbol->n_desc() & (N_NO_DEAD_STRIP|REFERENCED_DYNAMICALLY)) != 0); }
	virtual uint64_t							getSize() const					{ return fSymbol->n_value(); }
	virtual std::vector<ObjectFile::Reference*>&  getReferences() const			{ return fgNoReferences; }
	virtual bool								mustRemainInSection() const		{ return true; }
	virtual const char*							getSectionName() const;
	virtual ObjectFile::Segment&				getSegment() const				{ return DataSegment::fgSingleton; }
	virtual ObjectFile::Atom&					getFollowOnAtom() const			{ return *(ObjectFile::Atom*)NULL; }
	virtual std::vector<ObjectFile::LineInfo>*	getLineInfo() const				{ return NULL; }
	virtual ObjectFile::Alignment				getAlignment() const;
	virtual void								copyRawContent(uint8_t buffer[]) const;
	virtual void								setScope(ObjectFile::Atom::Scope newScope)		{ fScope = newScope; }
	virtual void								setSize(uint64_t size)			{ }
	virtual void								addReference(ObjectFile::Reference* ref) { throw "ld: can't add references"; }
	virtual void								sortReferences() { }
	virtual void								addLineInfo(const  ObjectFile::LineInfo& info)	{ throw "ld: can't add line info to tentative definition"; }
	virtual uint64_t							getObjectAddress() const		{ return ULLONG_MAX; }
	virtual const void*							getSectionRecord() const		{ return NULL; }

protected:
	typedef typename A::P					P;
	typedef typename A::P::E				E;
	typedef typename A::P::uint_t			pint_t;
	typedef typename A::ReferenceKinds		Kinds;
	friend class Reader<A>;

											TentativeAtom(Reader<A>&, const macho_nlist<P>*);
	virtual									~TentativeAtom() {}

	Reader<A>&									fOwner;
	const macho_nlist<P>*						fSymbol;
	ObjectFile::Atom::Scope						fScope;
	static std::vector<ObjectFile::Reference*>	fgNoReferences;
};

template <typename A>
std::vector<ObjectFile::Reference*> TentativeAtom<A>::fgNoReferences;

template <typename A>
TentativeAtom<A>::TentativeAtom(Reader<A>& owner, const macho_nlist<P>* symbol)
 : fOwner(owner), fSymbol(symbol)
{
	uint8_t type =  symbol->n_type();
	if ( (type & N_EXT) == 0 )
		fScope = ObjectFile::Atom::scopeTranslationUnit;
	else if ( (type & N_PEXT) != 0 )
		fScope = ObjectFile::Atom::scopeLinkageUnit;
	else
		fScope = ObjectFile::Atom::scopeGlobal;
	if ( ((type & N_TYPE) == N_UNDF) && (symbol->n_value() != 0) ) {
		// tentative definition
	}
	else {
		printf("unknown symbol type: %d\n", type);
	}
	//fprintf(stderr, "TentativeAtom(%p) %s\n", this, this->getDisplayName());
}


template <typename A>
ObjectFile::Alignment TentativeAtom<A>::getAlignment() const
{
	uint8_t alignment = GET_COMM_ALIGN(fSymbol->n_desc());
	if ( alignment == 0 ) {
		// common symbols align to their size
		// that is, a 4-byte common aligns to 4-bytes
		// if this size is not a power of two, 
		// then round up to the next power of two
		uint64_t size = this->getSize();
		alignment = 63 - (uint8_t)__builtin_clzll(size);
		if ( size != (1ULL << alignment) )
			++alignment;
	}
	// limit alignment of extremely large commons to 2^15 bytes (8-page)
	if ( alignment < 12 )
		return ObjectFile::Alignment(alignment);
	else
		return ObjectFile::Alignment(12);
}

template <typename A>
const char* TentativeAtom<A>::getSectionName() const
{
	if ( fOwner.fOptions.fForFinalLinkedImage || fOwner.fOptions.fMakeTentativeDefinitionsReal )
		return "__common"; 
	else
		return "._tentdef"; 
}


template <typename A>
void TentativeAtom<A>::copyRawContent(uint8_t buffer[]) const
{
	bzero(buffer, getSize());
}


//
// An AnonymousAtom represents compiler generated data that has no name.
// For instance, a literal C-string or a 64-bit floating point constant
// is represented by an AnonymousAtom.
//
template <typename A>
class AnonymousAtom : public BaseAtom
{
public:
	virtual ObjectFile::Reader*					getFile() const					{ return &fOwner; }
	virtual bool								getTranslationUnitSource(const char** dir, const char** name) const { return false; }
	virtual const char*							getName() const					{ return fSynthesizedName; }
	virtual const char*							getDisplayName() const;
	virtual ObjectFile::Atom::Scope				getScope() const;
	virtual ObjectFile::Atom::DefinitionKind	getDefinitionKind() const;
	virtual ObjectFile::Atom::SymbolTableInclusion getSymbolTableInclusion() const	{ return fSymbolTableInclusion; }
	virtual	bool								dontDeadStrip() const			{ return fDontDeadStrip; }
	virtual bool								isZeroFill() const;
	virtual uint64_t							getSize() const					{ return fSize; }
	virtual std::vector<ObjectFile::Reference*>&  getReferences() const			{ return (std::vector<ObjectFile::Reference*>&)(fReferences); }
	virtual bool								mustRemainInSection() const		{ return true; }
	virtual const char*							getSectionName() const;
	virtual Segment<A>&							getSegment() const				{ return *fSegment; }
	virtual ObjectFile::Atom&					getFollowOnAtom() const;
	virtual std::vector<ObjectFile::LineInfo>*	getLineInfo() const				{ return NULL; }
	virtual ObjectFile::Alignment				getAlignment() const;
	virtual void								copyRawContent(uint8_t buffer[]) const;
	virtual void								setScope(ObjectFile::Atom::Scope newScope)	{ fScope = newScope; }
	virtual void								setSize(uint64_t size)			{ fSize = size; }
	virtual void								addReference(ObjectFile::Reference* ref) { fReferences.push_back((Reference<A>*)ref); }
	virtual void								sortReferences() { std::sort(fReferences.begin(), fReferences.end(), ReferenceSorter()); }
	virtual void								addLineInfo(const  ObjectFile::LineInfo& info) { fprintf(stderr, "ld: can't add line info to anonymous symbol %s from %s\n", this->getDisplayName(), this->getFile()->getPath()); }
	virtual uint64_t							getObjectAddress() const		{ return fAddress; }
	virtual const void*							getSectionRecord() const		{ return (const void*)fSection; }
	BaseAtom*									redirectTo()					{ return fRedirect; }
	bool										isWeakImportStub()				{ return fWeakImportStub; }
	void										resolveName();
	
protected:
	typedef typename A::P						P;
	typedef typename A::P::E					E;
	typedef typename A::P::uint_t				pint_t;
	typedef typename A::ReferenceKinds			Kinds;
	typedef typename std::vector<Reference<A>*>			ReferenceVector;
	typedef typename ReferenceVector::iterator			ReferenceVectorIterator;		// seems to help C++ parser
	typedef typename ReferenceVector::const_iterator	ReferenceVectorConstIterator;	// seems to help C++ parser
	friend class Reader<A>;

											AnonymousAtom(Reader<A>&, const macho_section<P>*, uint32_t addr, uint32_t size);
	virtual									~AnonymousAtom() {}
	static bool									cstringsHaveLabels();

	Reader<A>&									fOwner;
	const char*									fSynthesizedName;
	const char*									fDisplayName;
	const macho_section<P>*						fSection;
	uint32_t									fAddress;
	uint32_t									fSize;
	Segment<A>*									fSegment;
	ReferenceVector								fReferences;
	BaseAtom*									fRedirect;
	bool										fDontDeadStrip;
	bool										fWeakImportStub;
	ObjectFile::Atom::SymbolTableInclusion		fSymbolTableInclusion;
	ObjectFile::Atom::Scope						fScope;
};

template <typename A>
AnonymousAtom<A>::AnonymousAtom(Reader<A>& owner, const macho_section<P>* section, uint32_t addr, uint32_t size)
 : fOwner(owner), fSynthesizedName(NULL), fDisplayName(NULL), fSection(section), fAddress(addr), fSize(size), 
	fSegment(NULL), fDontDeadStrip(true), fWeakImportStub(false), fSymbolTableInclusion(ObjectFile::Atom::kSymbolTableNotIn),
	fScope(ObjectFile::Atom::scopeTranslationUnit)
{
	fSegment = new Segment<A>(fSection);
	fRedirect = this;
	uint8_t type = fSection->flags() & SECTION_TYPE;
	//fprintf(stderr, "AnonymousAtom(%p) addr=0x%X in %s from %s\n", this, addr, section->sectname(), owner.getPath());
	switch ( type ) {
		case S_ZEROFILL:
			{
				asprintf((char**)&fSynthesizedName, "zero-fill-at-0x%08X", addr);
			}
			break;
		case S_COALESCED:
		case S_REGULAR:
			if ( (strcmp(section->sectname(), "__class") == 0) && (strcmp(section->segname(), "__OBJC") == 0) && owner.fAppleObjc ) {
				// special case ObjC classes to synthesize .objc_class_name_* symbols, for Apple runtime only
				fSynthesizedName = ".objc_class_name_PENDING";
				owner.fAtomsPendingAName.push_back(this);
				owner.fSectionsWithAtomsPendingAName.insert(fSection);
				if ( fOwner.fOptions.fForFinalLinkedImage ) 
					fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableIn;
				else
					fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableInAsAbsolute;
				fScope = ObjectFile::Atom::scopeGlobal;
			}
			else if ( strcmp(fSection->sectname(), "__cstring") == 0 ) {
				// handle .o files created by old ld64 -r that are missing cstring section type
				const char* str = (char*)(owner.fHeader) + section->offset() + addr - section->addr();
				asprintf((char**)&fSynthesizedName, "cstring=%s", str);
			}
			break;
		case S_CSTRING_LITERALS:
			{
				const char* str = (char*)(owner.fHeader) + section->offset() + addr - section->addr();
				asprintf((char**)&fSynthesizedName, "cstring=%s", str);
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				fDontDeadStrip = false;
				if ( !fOwner.fOptions.fForFinalLinkedImage && cstringsHaveLabels() ) 
					fSymbolTableInclusion = ObjectFile::Atom::kSymbolTableIn;
			}
			break;
		case S_4BYTE_LITERALS:
			{
				uint32_t value =  E::get32(*(uint32_t*)(((uint8_t*)owner.fHeader) + section->offset() + addr - section->addr()));
				asprintf((char**)&fSynthesizedName, "4-byte-literal=0x%08X", value);
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				fDontDeadStrip = false;
			}
			break;
		case S_8BYTE_LITERALS:
			{
				uint64_t value =  E::get64(*(uint64_t*)(((uint8_t*)owner.fHeader) + section->offset() + addr - section->addr()));
				asprintf((char**)&fSynthesizedName, "8-byte-literal=0x%016llX", value);
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				fDontDeadStrip = false;
			}
			break;
		case S_16BYTE_LITERALS:
			{
				uint64_t value1 =  E::get64(*(uint64_t*)(((uint8_t*)owner.fHeader) + section->offset() + addr - section->addr()));
				uint64_t value2 =  E::get64(*(uint64_t*)(((uint8_t*)owner.fHeader) + section->offset() + addr + 8 - section->addr()));
				asprintf((char**)&fSynthesizedName, "16-byte-literal=0x%016llX,%016llX", value1, value2);
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				fDontDeadStrip = false;
			}
			break;
		case S_LITERAL_POINTERS:
			{
				//uint32_t literalNameAddr =  P::getP(*(pint_t*)(((uint8_t*)owner.fHeader) + section->offset() + addr - section->addr()));
				//const char* str = (char*)(owner.fHeader) + section->offset() + literalNameAddr - section->addr();
				//asprintf((char**)&fSynthesizedName, "literal-pointer@%s@%s@%s", section->segname(), section->sectname(), str);
				fSynthesizedName = "literal-pointer-name-PENDING";
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				owner.fAtomsPendingAName.push_back(this);
				owner.fSectionsWithAtomsPendingAName.insert(fSection);
			}
			break;
		case S_MOD_INIT_FUNC_POINTERS:
				asprintf((char**)&fSynthesizedName, "initializer$%d", (addr - (uint32_t)fSection->addr())/sizeof(pint_t));
				break;
		case S_MOD_TERM_FUNC_POINTERS:
				asprintf((char**)&fSynthesizedName, "terminator$%d", (addr - (uint32_t)fSection->addr())/sizeof(pint_t));
				break;
		case S_SYMBOL_STUBS:
			{
				uint32_t index = (fAddress - fSection->addr()) / fSection->reserved2();
				index += fSection->reserved1();
				uint32_t symbolIndex = E::get32(fOwner.fIndirectTable[index]);
				const macho_nlist<P>* sym = &fOwner.fSymbols[symbolIndex];
				uint32_t strOffset = sym->n_strx();
				// want name to not have $stub suffix, this is what automatic stub generation expects
				fSynthesizedName = &fOwner.fStrings[strOffset];
				// check for weak import
				fWeakImportStub = fOwner.isWeakImportSymbol(sym);
				// sometimes the compiler gets confused and generates a stub to a static function
				// if so, we should redirect any call to the stub to be calls to the real static function atom
				if ( ((sym->n_type() & N_TYPE) != N_UNDF) && ((sym->n_type() & N_EXT) == 0) ) {
					BaseAtom* staticAtom = fOwner.findAtomByName(fSynthesizedName);
					if ( staticAtom != NULL ) 
						fRedirect = staticAtom;
				}
				// might be a spurious stub for a static function, make stub static too
				if ( (sym->n_type() & N_EXT) == 0 ) 
					fScope = ObjectFile::Atom::scopeTranslationUnit;
				else
					fScope = ObjectFile::Atom::scopeLinkageUnit;
			}
			break;
		case S_LAZY_SYMBOL_POINTERS:
		case S_NON_LAZY_SYMBOL_POINTERS:
			{
				fDontDeadStrip = false;
				fScope = ObjectFile::Atom::scopeLinkageUnit;
				uint32_t index = (fAddress - fSection->addr()) / sizeof(pint_t);
				index += fSection->reserved1();
				uint32_t symbolIndex = E::get32(fOwner.fIndirectTable[index]);
				if ( symbolIndex == INDIRECT_SYMBOL_LOCAL ) {
					// Silly codegen with non-lazy pointer to a local symbol
					uint32_t fileOffset = fSection->offset() - fSection->addr() + fAddress;
					pint_t nonLazyPtrValue = P::getP(*((pint_t*)((char*)(fOwner.fHeader)+fileOffset)));
					// All atoms not created yet, so we need to scan symbol table
					const macho_nlist<P>* closestSym = NULL; 
					const macho_nlist<P>* end = &fOwner.fSymbols[fOwner.fSymbolCount];
					for (const macho_nlist<P>* sym =  fOwner.fSymbols; sym < end; ++sym) {
						if ( ((sym->n_type() & N_TYPE) == N_SECT) 
						 && ((sym->n_type() & N_STAB) == 0) ) {
							if ( sym->n_value() == nonLazyPtrValue ) {
								const char* name = &fOwner.fStrings[sym->n_strx()];
								char* str = new char[strlen(name)+16];
								strcpy(str, name);
								strcat(str, "$non_lazy_ptr");
								fSynthesizedName = str;
								// add direct reference to target later, because its atom may not be constructed yet
								fOwner.fLocalNonLazys.push_back(this);
								fScope = ObjectFile::Atom::scopeTranslationUnit;
								return;
							}
							else if ( (sym->n_value() < nonLazyPtrValue) && ((closestSym == NULL) || (sym->n_value() > closestSym->n_value())) ) {
								closestSym = sym;
							}
						}
					}
					// add direct reference to target later, because its atom may not be constructed yet
					if ( closestSym != NULL ) {
						const char* name = &fOwner.fStrings[closestSym->n_strx()];
						char* str;
						asprintf(&str, "%s+%u$non_lazy_ptr", name, nonLazyPtrValue - closestSym->n_value());
						fSynthesizedName = str;
					}
					else {
						fSynthesizedName = "$interior$non_lazy_ptr";
					}
					fScope = ObjectFile::Atom::scopeTranslationUnit;
					fOwner.fLocalNonLazys.push_back(this);
					return;
				}
				const macho_nlist<P>* targetSymbol = &fOwner.fSymbols[symbolIndex];
				const char* name = &fOwner.fStrings[targetSymbol->n_strx()];
				char* str = new char[strlen(name)+16];
				strcpy(str, name);
				if ( type == S_LAZY_SYMBOL_POINTERS )
					strcat(str, "$lazy_ptr");
				else
					strcat(str, "$non_lazy_ptr");
				fSynthesizedName = str;

				// optimize __IMPORT segment out of i386 dyld
				if ( fOwner.fOptions.fForDyld  && (strcmp(fSection->segname(),"__IMPORT") == 0) ) {
					macho_section<P>* dummySection = new macho_section<P>(*fSection);
					dummySection->set_segname("__DATA");
					fSection = dummySection;
					fSegment = new Segment<A>(fSection);
				}
				
				if ( (targetSymbol->n_type() & N_EXT) == 0 ) {
					// target is translation unit scoped, so add direct reference to target
					//fOwner.makeReference(A::kPointer, addr, targetSymbol->n_value());
					new Reference<A>(A::kPointer, AtomAndOffset(this), fOwner.findAtomAndOffset(targetSymbol->n_value()));
				}
				else {	
					if ( fOwner.isWeakImportSymbol(targetSymbol) )
						new Reference<A>(A::kPointerWeakImport, AtomAndOffset(this), name, 0);
					else
						new Reference<A>(A::kPointer, AtomAndOffset(this), name, 0);
				}
			}
			break;
		default:
			throwf("section type %d not supported with address=0x%08X", type, addr);
	}
	//fprintf(stderr, "AnonymousAtom(%p) %s \n", this, this->getDisplayName());
}

// x86_64 uses L labels on cstrings to allow relocs with addends
template <> bool AnonymousAtom<x86_64>::cstringsHaveLabels() { return true; }
template <typename A> bool AnonymousAtom<A>::cstringsHaveLabels() { return false; }


template <typename A>
void AnonymousAtom<A>::resolveName()
{
	if ( (strcmp(fSection->sectname(), "__class") == 0) && (strcmp(fSection->segname(), "__OBJC") == 0) ) {
		std::vector<ObjectFile::Reference*>&  references = this->getReferences();
		// references are not yet sorted, so scan the vector
		for (std::vector<ObjectFile::Reference*>::iterator rit=references.begin(); rit != references.end(); rit++) {
			if ( ((*rit)->getFixUpOffset() == sizeof(pint_t)) && ((*rit)->getKind() == A::kPointer) ) {
				const char* superStr = (*rit)->getTargetName();
				if ( strncmp(superStr, "cstring=", 8) == 0 ) {
					const char* superClassName;
					asprintf((char**)&superClassName, ".objc_class_name_%s", &superStr[8]);
					new Reference<A>(A::kNoFixUp, AtomAndOffset(this), superClassName, 0);
				}
				break;
			}
		}
		for (std::vector<ObjectFile::Reference*>::iterator rit=references.begin(); rit != references.end(); rit++) {
			if ( ((*rit)->getFixUpOffset() == 2*sizeof(pint_t)) && ((*rit)->getKind() == A::kPointer) ) {
				const char* classStr = (*rit)->getTargetName();
				if ( strncmp(classStr, "cstring=", 8) == 0 ) {
					asprintf((char**)&fSynthesizedName, ".objc_class_name_%s", &classStr[8]);
				}
				break;
			}
		}
	}
	else if ( (fSection->flags() & SECTION_TYPE) == S_LITERAL_POINTERS) {
		ObjectFile::Reference* ref = this->getReferences()[0];
		const char* str = ref->getTargetName();
		if ( strncmp(str, "cstring=", 8) == 0 ) {
			asprintf((char**)&fSynthesizedName, "literal-pointer@%s@%s@%s", fSection->segname(), fSection->sectname(), &str[8]);
		}
	}
}


template <typename A>
const char* AnonymousAtom<A>::getDisplayName() const
{
	if ( fSynthesizedName != NULL )
		return fSynthesizedName;

	if ( fDisplayName != NULL )
		return fDisplayName;

	if ( (fSection->flags() & SECTION_TYPE) == S_CSTRING_LITERALS ) {
		uint32_t fileOffset = fSection->offset() - fSection->addr() + fAddress;
		asprintf((char**)&fDisplayName, "atom string literal: \"%s\"", (char*)(fOwner.fHeader)+fileOffset);
	}
	else {
		asprintf((char**)&fDisplayName, "%s@%d", fSection->sectname(), fAddress - (uint32_t)fSection->addr() );
	}
	return fDisplayName;
}


template <typename A>
ObjectFile::Atom::Scope AnonymousAtom<A>::getScope() const
{
	return fScope;
}

template <typename A>
ObjectFile::Atom::DefinitionKind AnonymousAtom<A>::getDefinitionKind() const
{
	// in order for literals to be coalesced they must be weak
	switch ( fSection->flags() & SECTION_TYPE ) {
		case S_CSTRING_LITERALS:
		case S_4BYTE_LITERALS:
		case S_8BYTE_LITERALS:
		case S_16BYTE_LITERALS:
		case S_SYMBOL_STUBS:
		case S_LITERAL_POINTERS:
			return ObjectFile::Atom::kWeakDefinition;
		case S_NON_LAZY_SYMBOL_POINTERS:
			if ( fScope == ObjectFile::Atom::scopeTranslationUnit )
				return ObjectFile::Atom::kRegularDefinition;
			else
				return ObjectFile::Atom::kWeakDefinition;
		default:
			return ObjectFile::Atom::kRegularDefinition;
	}
}

template <typename A>
bool AnonymousAtom<A>::isZeroFill() const
{
	return ( (fSection->flags() & SECTION_TYPE) == S_ZEROFILL );
}


template <typename A>
const char*	AnonymousAtom<A>::getSectionName() const
{
	if ( strlen(fSection->sectname()) > 15 ) {
		static char temp[18];
		strncpy(temp, fSection->sectname(), 16);
		temp[17] = '\0';
		return temp;
	}
	return fSection->sectname();
}

template <typename A>
ObjectFile::Alignment AnonymousAtom<A>::getAlignment() const
{
	switch ( fSection->flags() & SECTION_TYPE ) {
		case S_4BYTE_LITERALS:
			return ObjectFile::Alignment(2);
		case S_8BYTE_LITERALS:
			return ObjectFile::Alignment(3);
		case S_16BYTE_LITERALS:
			return ObjectFile::Alignment(4);
		case S_NON_LAZY_SYMBOL_POINTERS:
			return ObjectFile::Alignment((uint8_t)log2(sizeof(pint_t)));
		case S_CSTRING_LITERALS:
			if ( ! fOwner.fOptions.fForFinalLinkedImage )
				return ObjectFile::Alignment(fSection->align());
		default:
			return ObjectFile::Alignment(fSection->align(), fAddress % (1 << fSection->align()));
	}
}


template <typename A>
ObjectFile::Atom& AnonymousAtom<A>::getFollowOnAtom() const
{
	for (ReferenceVectorConstIterator it=fReferences.begin(); it != fReferences.end(); it++) {
		Reference<A>* ref = *it;
		if ( ref->getKind() == A::kFollowOn )
			return ref->getTarget();
	}
	return *((ObjectFile::Atom*)NULL);
}

template <typename A>
void AnonymousAtom<A>::copyRawContent(uint8_t buffer[]) const
{
	// copy base bytes
	if ( isZeroFill() )
		bzero(buffer, fSize);
	else {
		uint32_t fileOffset = fSection->offset() - fSection->addr() + fAddress;
		memcpy(buffer, (char*)(fOwner.fHeader)+fileOffset, fSize);
	}
}


//
// An AbsoluteAtom represents an N_ABS symbol which can only be created in 
// assembly language and usable by static executables such as the kernel/
//
template <typename A>
class AbsoluteAtom : public BaseAtom
{
public:
	virtual ObjectFile::Reader*					getFile() const					{ return &fOwner; }
	virtual bool								getTranslationUnitSource(const char** dir, const char** name) const
																				{ return fOwner.getTranslationUnitSource(dir, name); }
	virtual const char*							getName() const					{ return &fOwner.fStrings[fSymbol->n_strx()]; }
	virtual const char*							getDisplayName() const			{ return getName(); }
	virtual ObjectFile::Atom::Scope				getScope() const				{ return fScope; }
	virtual ObjectFile::Atom::DefinitionKind	getDefinitionKind() const		{ return ObjectFile::Atom::kAbsoluteSymbol; }
	virtual bool								isZeroFill() const				{ return false; }
	virtual SymbolTableInclusion				getSymbolTableInclusion() const	{ return ObjectFile::Atom::kSymbolTableInAsAbsolute; }
	virtual	bool								dontDeadStrip() const			{ return false; }
	virtual uint64_t							getSize() const					{ return 0; }
	virtual std::vector<ObjectFile::Reference*>&  getReferences() const			{ return fgNoReferences; }
	virtual bool								mustRemainInSection() const		{ return true; }
	virtual const char*							getSectionName() const			{ return "._absolute"; } 
	virtual ObjectFile::Segment&				getSegment() const				{ return LinkEditSegment::fgSingleton; }
	virtual ObjectFile::Atom&					getFollowOnAtom() const			{ return *(ObjectFile::Atom*)NULL; }
	virtual std::vector<ObjectFile::LineInfo>*	getLineInfo() const				{ return NULL; }
	virtual ObjectFile::Alignment				getAlignment() const			{ return ObjectFile::Alignment(0); }
	virtual void								copyRawContent(uint8_t buffer[]) const	{ }
	virtual void								setScope(ObjectFile::Atom::Scope newScope)		{ fScope = newScope; }
	virtual void								setSize(uint64_t size)			{ }
	virtual void								addReference(ObjectFile::Reference* ref) { throw "ld: can't add references"; }
	virtual void								sortReferences()				{ }
	virtual void								addLineInfo(const  ObjectFile::LineInfo& info)	{ throw "ld: can't add line info to tentative definition"; }
	virtual uint64_t							getObjectAddress() const		{ return fSymbol->n_value(); }
	virtual void								setSectionOffset(uint64_t offset) { /* don't let fSectionOffset be altered*/ }
	virtual const void*							getSectionRecord() const		{ return NULL; }

protected:
	typedef typename A::P					P;
	typedef typename A::P::E				E;
	typedef typename A::P::uint_t			pint_t;
	typedef typename A::ReferenceKinds		Kinds;
	friend class Reader<A>;

											AbsoluteAtom(Reader<A>&, const macho_nlist<P>*);
	virtual									~AbsoluteAtom() {}

	Reader<A>&									fOwner;
	const macho_nlist<P>*						fSymbol;
	ObjectFile::Atom::Scope						fScope;
	static std::vector<ObjectFile::Reference*>	fgNoReferences;
};

template <typename A>
std::vector<ObjectFile::Reference*> AbsoluteAtom<A>::fgNoReferences;

template <typename A>
AbsoluteAtom<A>::AbsoluteAtom(Reader<A>& owner, const macho_nlist<P>* symbol)
 : fOwner(owner), fSymbol(symbol)
{
	// store absolute adress in fSectionOffset
	fSectionOffset = symbol->n_value();
	// compute scope
	uint8_t type =  symbol->n_type();
	if ( (type & N_EXT) == 0 )
		fScope = ObjectFile::Atom::scopeTranslationUnit;
	else if ( (type & N_PEXT) != 0 )
		fScope = ObjectFile::Atom::scopeLinkageUnit;
	else
		fScope = ObjectFile::Atom::scopeGlobal;
	//fprintf(stderr, "AbsoluteAtom(%p) %s\n", this, this->getDisplayName());
}



template <typename A>
class Reader : public ObjectFile::Reader
{
public:
	static bool										validFile(const uint8_t* fileContent);
													Reader(const uint8_t* fileContent, const char* path, time_t modTime, 
														const ObjectFile::ReaderOptions& options, uint32_t ordinalBase);
	virtual											~Reader() {}

	virtual const char*								getPath()				{ return fPath; }
	virtual time_t									getModificationTime()	{ return fModTime; }
	virtual ObjectFile::Reader::DebugInfoKind		getDebugInfoKind()		{ return fDebugInfo; }
	virtual std::vector<class ObjectFile::Atom*>&	getAtoms()				{ return (std::vector<class ObjectFile::Atom*>&)(fAtoms); }
	virtual std::vector<class ObjectFile::Atom*>*	getJustInTimeAtomsFor(const char* name) { return NULL; }
	virtual std::vector<Stab>*						getStabs()				{ return &fStabs; }
	virtual ObjectFile::Reader::ObjcConstraint		getObjCConstraint()		{ return fObjConstraint; }
	virtual ObjectFile::Reader::CpuConstraint		getCpuConstraint()		{ return fCpuConstraint; }
	virtual bool									canScatterAtoms()		{ return (fHeader->flags() & MH_SUBSECTIONS_VIA_SYMBOLS); }
	virtual bool									objcReplacementClasses(){ return fReplacementClasses; }

	 bool											getTranslationUnitSource(const char** dir, const char** name) const;

private:
	typedef typename A::P						P;
	typedef typename A::P::E					E;
	typedef typename A::P::uint_t				pint_t;
	//typedef typename std::vector<Atom<A>*>		AtomVector;
	//typedef typename AtomVector::iterator		AtomVectorIterator;	// seems to help C++ parser
	typedef typename A::ReferenceKinds			Kinds;
	friend class AnonymousAtom<A>;
	friend class TentativeAtom<A>;
	friend class AbsoluteAtom<A>;
	friend class SymbolAtom<A>;

	void										addReferencesForSection(const macho_section<P>* sect);
	bool										addRelocReference(const macho_section<P>* sect, const macho_relocation_info<P>* reloc);
	bool										addRelocReference_powerpc(const macho_section<P>* sect, const macho_relocation_info<P>* reloc);
	Kinds										pointerDiffKindForLength_powerpc(uint8_t r_length);
	bool										read_comp_unit(const char ** name, const char ** comp_dir, uint64_t *stmt_list);
	static bool									isWeakImportSymbol(const macho_nlist<P>* sym);
	static bool									skip_form(const uint8_t ** offset, const uint8_t * end, uint64_t form, uint8_t addr_size, bool dwarf64);
	static const char*							assureFullPath(const char* path);
	AtomAndOffset								findAtomAndOffset(uint32_t addr);
	AtomAndOffset								findAtomAndOffset(uint32_t baseAddr, uint32_t realAddr);
	Reference<A>*								makeReference(Kinds kind, uint32_t atAddr, uint32_t toAddr);
	Reference<A>*								makeReference(Kinds kind, uint32_t atAddr, uint32_t fromAddr, uint32_t toAddr);
	Reference<A>*								makeReferenceWithToBase(Kinds kind, uint32_t atAddr, uint32_t toAddr, uint32_t toBaseAddr);
	Reference<A>*								makeReferenceWithToBase(Kinds kind, uint32_t atAddr, uint32_t fromAddr, uint32_t toAddr, uint32_t toBaseAddr);
	Reference<A>*								makeByNameReference(Kinds kind, uint32_t atAddr, const char* toName, uint32_t toOffset);
	Reference<A>*								makeReferenceToEH(const char* ehName, pint_t ehAtomAddress, const macho_section<P>* ehSect);
	Reference<A>*								makeReferenceToSymbol(Kinds kind, uint32_t atAddr, const macho_nlist<P>* toSymbol, uint32_t toOffset);
	void										validSectionType(uint8_t type);
	void										addDtraceExtraInfos(uint32_t probeAddr, const char* providerName);
	void										setCpuConstraint(uint32_t cpusubtype);

	BaseAtom*									findAtomByName(const char*);

	const char*									fPath;
	time_t										fModTime;
	uint32_t									fOrdinalBase;
	const ObjectFile::ReaderOptions&			fOptions;
	const macho_header<P>*						fHeader;
	const char*									fStrings;
	const macho_nlist<P>*						fSymbols;
	uint32_t									fSymbolCount;
	const macho_segment_command<P>*				fSegment;
	const uint32_t*								fIndirectTable;
	std::vector<BaseAtom*>						fAtoms;
	std::map<uint32_t, BaseAtom*>				fAddrToAtom;
	std::map<uint32_t, BaseAtom*>				fAddrToAbsoluteAtom;
	std::vector<class AnonymousAtom<A>*>		fLocalNonLazys;
	std::vector<class AnonymousAtom<A>*>		fAtomsPendingAName;
	std::set<const macho_section<P>*>			fSectionsWithAtomsPendingAName;
	std::vector<const char*>					fDtraceProviderInfo;
	ObjectFile::Reader::DebugInfoKind			fDebugInfo;
	bool										fHasUUID;
	const macho_section<P>*						fDwarfDebugInfoSect;
	const macho_section<P>*						fDwarfDebugAbbrevSect;
	const macho_section<P>*						fDwarfDebugLineSect;
	const char*									fDwarfTranslationUnitDir;
	const char*									fDwarfTranslationUnitFile;
	std::map<uint32_t,const char*>				fDwarfIndexToFile;
	std::vector<Stab>							fStabs;
	bool										fAppleObjc;
	bool										fHasDTraceProbes;
	bool										fHaveIndirectSymbols;
	bool										fReplacementClasses;
	ObjectFile::Reader::ObjcConstraint			fObjConstraint;
	ObjectFile::Reader::CpuConstraint			fCpuConstraint;
};

template <typename A>
Reader<A>::Reader(const uint8_t* fileContent, const char* path, time_t modTime, const ObjectFile::ReaderOptions& options, uint32_t ordinalBase)
	: fPath(strdup(path)), fModTime(modTime), fOrdinalBase(ordinalBase), fOptions(options), fHeader((const macho_header<P>*)fileContent),
	 fStrings(NULL), fSymbols(NULL), fSymbolCount(0), fSegment(NULL), fIndirectTable(NULL),
	 fDebugInfo(kDebugInfoNone), fHasUUID(false), fDwarfDebugInfoSect(NULL), fDwarfDebugAbbrevSect(NULL), fDwarfDebugLineSect(NULL),
	  fDwarfTranslationUnitDir(NULL), fDwarfTranslationUnitFile(NULL), fAppleObjc(false), fHasDTraceProbes(false),
	  fHaveIndirectSymbols(false), fReplacementClasses(false), 
	  fObjConstraint(ObjectFile::Reader::kObjcNone), fCpuConstraint(ObjectFile::Reader::kCpuAny) 
{
	// sanity check
	if ( ! validFile(fileContent) )
		throw "not a valid mach-o object file";

	Reference<A>::fgForFinalLinkedImage = options.fForFinalLinkedImage;

	// write out path for -t or -whatsloaded option
	if ( options.fLogObjectFiles || options.fLogAllFiles )
		printf("%s\n", path);

	// cache intersting pointers
	const macho_header<P>* header = (const macho_header<P>*)fileContent;
	this->setCpuConstraint(header->cpusubtype());
	const uint32_t cmd_count = header->ncmds();
	const macho_load_command<P>* const cmds = (macho_load_command<P>*)((char*)header + sizeof(macho_header<P>));
	const macho_load_command<P>* cmd = cmds;
	uint32_t undefinedStartIndex = 0;
	uint32_t undefinedEndIndex = 0;
	for (uint32_t i = 0; i < cmd_count; ++i) {
		switch (cmd->cmd()) {
		    case LC_SYMTAB:
				{
					const macho_symtab_command<P>* symtab = (macho_symtab_command<P>*)cmd;
					fSymbolCount = symtab->nsyms();
					fSymbols = (const macho_nlist<P>*)((char*)header + symtab->symoff());
					fStrings = (char*)header + symtab->stroff();
					if ( undefinedEndIndex == 0 ) {
						undefinedStartIndex = 0;
						undefinedEndIndex = symtab->nsyms();
					}
				}
				break;
			case LC_DYSYMTAB:
				{
					const macho_dysymtab_command<P>* dsymtab = (struct macho_dysymtab_command<P>*)cmd;
					fIndirectTable = (uint32_t*)((char*)fHeader + dsymtab->indirectsymoff());
					undefinedStartIndex = dsymtab->iundefsym();
					undefinedEndIndex = undefinedStartIndex + dsymtab->nundefsym();
				}
				break;
		    case LC_UUID:
				fHasUUID = true;
				break;

			default:
				if ( cmd->cmd() == macho_segment_command<P>::CMD ) {
					fSegment = (macho_segment_command<P>*)cmd;
				}
				break;
		}
		cmd = (const macho_load_command<P>*)(((char*)cmd)+cmd->cmdsize());
	}
	const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)fSegment + sizeof(macho_segment_command<P>));
	const macho_section<P>* const sectionsEnd = &sectionsStart[fSegment->nsects()];

	// inital guess for number of atoms
	fAtoms.reserve(fSymbolCount);

	// add all atoms that have entries in symbol table
	const macho_section<P>* sections = (macho_section<P>*)((char*)fSegment + sizeof(macho_segment_command<P>));
	for (int i=fSymbolCount-1; i >= 0 ; --i) {
		// walk backwards through symbol table so globals are see before locals, otherwise a local alias would beome the reaal name
		const macho_nlist<P>& sym = fSymbols[i];
		if ( (sym.n_type() & N_STAB) == 0 ) {
			uint8_t type =  (sym.n_type() & N_TYPE);
			if ( type == N_SECT ) {
				const macho_section<P>* section	= &sections[sym.n_sect()-1];
				pint_t sectionEndAddr = section->addr() + section->size();
				bool suppress = false;
				// ignore atoms in debugger sections
				if ( (section->flags() & S_ATTR_DEBUG) == 0 ) {
					if ( strncmp(&fStrings[sym.n_strx()], "__dtrace_probe$", 15) == 0 ) {
						// ignore dtrace probe labels 
						fHasDTraceProbes = true;
					}
					else if ( fStrings[sym.n_strx()] == 'L' ) {
						// ignore L labels, <rdar://problem/3962731>
					}
					else {
						// ignore labels for atoms in other sections
						switch ( section->flags() & SECTION_TYPE ) {
							case S_REGULAR:
								if ( (sym.n_desc() & N_WEAK_DEF) && strcmp(section->sectname(), "__picsymbolstub1__TEXT") == 0 )
									suppress = true; // ignore stubs in crt1.o built by old ld64 that was missing S_SYMBOL_STUBS
							case S_ZEROFILL:
							case S_COALESCED:
							case S_4BYTE_LITERALS:
							case S_8BYTE_LITERALS:
							case S_16BYTE_LITERALS:
							case S_CSTRING_LITERALS:
								{
									BaseAtom* newAtom;
									std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAtom.find(sym.n_value());
									if ( (pos != fAddrToAtom.end()) && (strcmp(pos->second->getSectionName(), section->sectname())==0) ) {
										// another label to an existing address in the same section, make this an alias
										newAtom = new SymbolAliasAtom<A>(&fStrings[sym.n_strx()], &sym, *pos->second);
									}
									else {
										// make SymbolAtom atom for this address
										newAtom = new SymbolAtom<A>(*this, &sym, section);
										// don't add symbols at end of section to addr->atom map
										if ( sym.n_value() != sectionEndAddr )
											fAddrToAtom[sym.n_value()] = newAtom;
									}
									if ( ! suppress )
										fAtoms.push_back(newAtom);
									}
								break;
							case S_SYMBOL_STUBS:
							case S_LAZY_SYMBOL_POINTERS:
							case S_NON_LAZY_SYMBOL_POINTERS:
								// ignore symboled stubs produces by old ld64
								break;
							default:
								fprintf(stderr, "ld: warning symbol %s found in unsupported section in %s\n",
									&fStrings[sym.n_strx()], this->getPath());
						}
					}
				}
			}
			else if ( (type == N_UNDF) && (sym.n_value() != 0) ) {
				fAtoms.push_back(new TentativeAtom<A>(*this, &sym));
			}
			else if ( type == N_ABS ) {
				const char* symName = &fStrings[sym.n_strx()];
				if ( strncmp(symName, ".objc_class_name_", 16) == 0 ) {
					// ignore .objc_class_name_* symbols 
					fAppleObjc = true;
				}
				else if ( strcmp(&symName[strlen(symName)-3], ".eh") == 0 ) {
					// ignore empty *.eh symbols
				}
				else {
					BaseAtom* abAtom = new AbsoluteAtom<A>(*this, &sym);
					fAtoms.push_back(abAtom);
					fAddrToAbsoluteAtom[sym.n_value()] = abAtom;
				}
			}
			else if ( type == N_INDR ) {
				fHaveIndirectSymbols = true;
			}
		}
	}

	// add all fixed size anonymous atoms from special sections
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		uint32_t atomSize = 0;
		uint8_t type (sect->flags() & SECTION_TYPE);
		validSectionType(type);
		bool suppress = false;
		switch ( type ) {
			case S_SYMBOL_STUBS:
				suppress = true;
				atomSize = sect->reserved2();
				break;
			case S_LAZY_SYMBOL_POINTERS:
				suppress = true;
				atomSize = sizeof(pint_t);
				break;
			case S_NON_LAZY_SYMBOL_POINTERS:
			case S_LITERAL_POINTERS:
			case S_MOD_INIT_FUNC_POINTERS:
			case S_MOD_TERM_FUNC_POINTERS:
				atomSize = sizeof(pint_t);
				break;
			case S_INTERPOSING:
				atomSize = sizeof(pint_t)*2;
				break;
			case S_4BYTE_LITERALS:
				atomSize = 4;
				break;
			case S_8BYTE_LITERALS:
				atomSize = 8;
				break;
			case S_16BYTE_LITERALS:
				atomSize = 16;
				break;
			case S_REGULAR:
				// special case ObjC classes to synthesize .objc_class_name_* symbols
				if ( (strcmp(sect->sectname(), "__class") == 0) && (strcmp(sect->segname(), "__OBJC") == 0) && fAppleObjc ) {
					// gcc sometimes over aligns class structure
					uint32_t align = 1 << sect->align();
					atomSize = ((12 * sizeof(pint_t)) + align-1) & (-align);
				}
				// get objc Garbage Collection info
				else if ( ((strcmp(sect->sectname(), "__image_info") == 0) && (strcmp(sect->segname(), "__OBJC") == 0))
					   || ((strncmp(sect->sectname(), "__objc_imageinfo", 16) == 0) && (strcmp(sect->segname(), "__DATA") == 0)) ) {
					//	struct objc_image_info  {
					//		uint32_t	version;	// initially 0
					//		uint32_t	flags;
					//	};
					// #define OBJC_IMAGE_SUPPORTS_GC   2
					// #define OBJC_IMAGE_GC_ONLY       4
					//
					const uint32_t* contents = (uint32_t*)(((char*)fHeader) + sect->offset());
					if ( (sect->size() >= 8) && (contents[0] == 0) ) {
						uint32_t flags = E::get32(contents[1]);
						if ( (flags & 4) == 4 )
							fObjConstraint = ObjectFile::Reader::kObjcGC;
						else if ( (flags & 2) == 2 )
							fObjConstraint = ObjectFile::Reader::kObjcRetainReleaseOrGC;
						else
							fObjConstraint = ObjectFile::Reader::kObjcRetainRelease;
						if ( (flags & 1) == 1 )
							fReplacementClasses = true;
						// don't make atom for this section
						atomSize = sect->size();
						suppress = true;
					}
					else {
						fprintf(stderr, "can't parse __OBJC/__image_info section in %s\n", fPath);
					}
				}
				break;
		}
		if ( atomSize != 0 ) {
			for(uint32_t sectOffset=0; sectOffset < sect->size(); sectOffset += atomSize) {
				uint32_t atomAddr = sect->addr() + sectOffset;
				// add if not already an atom at that address
				if ( fAddrToAtom.find(atomAddr) == fAddrToAtom.end() ) {
					AnonymousAtom<A>* newAtom = new AnonymousAtom<A>(*this, sect, atomAddr, atomSize);
					if ( !suppress )
						fAtoms.push_back(newAtom);
					fAddrToAtom[atomAddr] = newAtom->redirectTo();
				}
			}
		}
	}

	// add all c-string anonymous atoms
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		if ( ((sect->flags() & SECTION_TYPE) == S_CSTRING_LITERALS) || strcmp(sect->sectname(), "__cstring") == 0 ) {
			uint32_t stringLen;
			uint32_t stringAddr;
			BaseAtom* mostAlignedEmptyString = NULL;
			uint32_t mostAlignedEmptyStringTrailingZeros = 0;
			std::vector<std::pair<uint32_t,BaseAtom*> > emptyStrings;
			for(uint32_t sectOffset=0; sectOffset < sect->size(); sectOffset += stringLen) {
				stringAddr = sect->addr() + sectOffset;
				stringLen  = strlen((char*)(fHeader) + sect->offset() + sectOffset) + 1;
				// add if not already an atom at that address
				if ( fAddrToAtom.find(stringAddr) == fAddrToAtom.end() ) {
					BaseAtom* newAtom = new AnonymousAtom<A>(*this, sect, stringAddr, stringLen);
					if ( stringLen == 1 ) {
						// because of padding it may look like there are lots of empty strings, keep track of all
						emptyStrings.push_back(std::make_pair<uint32_t,BaseAtom*>(stringAddr, newAtom));
						// record empty string with greatest alignment requirement
						uint32_t stringAddrTrailingZeros = (stringAddr==0) ? sect->align() : __builtin_ctz(stringAddr);
						if ( (mostAlignedEmptyString == NULL) 
							|| ( stringAddrTrailingZeros > mostAlignedEmptyStringTrailingZeros) ) {
							mostAlignedEmptyString = newAtom;
							mostAlignedEmptyStringTrailingZeros = stringAddrTrailingZeros;
						}
					}
					else {
						fAtoms.push_back(newAtom);
						fAddrToAtom[stringAddr] = newAtom;
					}
				}
			}
			// map all uses of empty strings to the most aligned one
			if ( mostAlignedEmptyString != NULL ) {
				// make most aligned atom a real atom
				fAtoms.push_back(mostAlignedEmptyString);
				// map all other empty atoms to this one
				for (std::vector<std::pair<uint32_t,BaseAtom*> >::iterator it=emptyStrings.begin(); it != emptyStrings.end(); it++) {
					fAddrToAtom[it->first] = mostAlignedEmptyString;
				}
			}
		}
	}

	// sort all atoms so far by address and section
	std::sort(fAtoms.begin(), fAtoms.end(), BaseAtomSorter());

	//fprintf(stderr, "sorted atoms:\n");
	//for (std::vector<BaseAtom*>::iterator it=fAtoms.begin(); it != fAtoms.end(); it++) 
	//	fprintf(stderr, "0x%08llX %s\n", (*it)->getObjectAddress(), (*it)->getDisplayName());

	// create atoms to cover any non-debug ranges not handled above
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		pint_t sectionStartAddr = sect->addr();
		pint_t sectionEndAddr   = sect->addr() + sect->size();
		const bool setFollowOnAtom = ! this->canScatterAtoms();
		if ( sect->size() != 0 ) {
			// ignore dwarf sections.  If ld every supports processing dwarf, this logic will need to change
			if ( (sect->flags() & S_ATTR_DEBUG) != 0 ) {
				fDebugInfo = kDebugInfoDwarf;
				if ( strcmp(sect->sectname(), "__debug_info") == 0 )
					fDwarfDebugInfoSect = sect;
				else if ( strcmp(sect->sectname(), "__debug_abbrev") == 0 )
					fDwarfDebugAbbrevSect = sect;
				else if ( strcmp(sect->sectname(), "__debug_line") == 0 )
					fDwarfDebugLineSect = sect;
			}
			else {
				if ( strcmp(sect->segname(), "__DWARFA") == 0 ) {
					throw "object file contains old DWARF debug info - rebuild with newer compiler";
				}
				uint8_t type (sect->flags() & SECTION_TYPE);
				switch ( type ) {
					case S_REGULAR:
					case S_ZEROFILL:
					case S_COALESCED:
						// if there is not an atom already at the start of this section, add an anonymous one
						uint32_t previousAtomAddr = 0;
						BaseAtom* previousAtom = NULL;
						if ( fAddrToAtom.find(sectionStartAddr) == fAddrToAtom.end() ) {
							BaseAtom* newAtom = new AnonymousAtom<A>(*this, sect, sect->addr(), 0);
							fAddrToAtom[sect->addr()] = newAtom;
							fAtoms.push_back(newAtom);
							previousAtomAddr = sectionStartAddr;
							previousAtom = newAtom;
							std::sort(fAtoms.begin(), fAtoms.end(), BaseAtomSorter());
						}
						// calculate size of all atoms in this section and add follow-on references
						for (std::vector<BaseAtom*>::iterator it=fAtoms.begin(); it != fAtoms.end(); it++) {
							BaseAtom* atom = (BaseAtom*)(*it);
							uint32_t atomAddr = atom->getObjectAddress();
							if ( atom->getSectionRecord() == sect ) {
								//fprintf(stderr, "addr=0x%08X, atom=%s\n", atomAddr, atom->getDisplayName());
								if ( (previousAtom != NULL) && (previousAtomAddr != atomAddr) ) {
									previousAtom->setSize(atomAddr - previousAtomAddr);
									if ( setFollowOnAtom && (atom != previousAtom) )
										new Reference<A>(A::kFollowOn, AtomAndOffset(previousAtom), AtomAndOffset(atom));
								}
								previousAtomAddr = atomAddr;
								previousAtom = atom;
							} 
						}
						if ( previousAtom != NULL ) {
							// set last atom in section
							previousAtom->setSize(sectionEndAddr - previousAtomAddr);
						}
						break;
				}
			}
		}
	}

	// check for object file that defines no objc classes, but uses objc classes
	// check for dtrace provider info
	for (uint32_t i=undefinedStartIndex; i < undefinedEndIndex; ++i) {
		const macho_nlist<P>& sym = fSymbols[i];
		if ( (sym.n_type() & N_STAB) == 0 ) {
			if ( (sym.n_type() & N_TYPE) == N_UNDF ) {
				const char* undefinedName = &fStrings[sym.n_strx()];
				if ( !fAppleObjc && (strncmp(undefinedName, ".objc_class_name_", 16) == 0) ) {
					fAppleObjc = true;
				}
				else if ( strncmp(undefinedName, "___dtrace_", 10) == 0 ) {
					if ( strchr(undefinedName, '$') != NULL  ) {
						if ( (strncmp(&undefinedName[10], "probe$", 6) != 0) && (strncmp(&undefinedName[10], "isenabled$", 10) != 0) ) {
							// any undefined starting with __dtrace_*$ that is not ___dtrace_probe$* or ___dtrace_isenabled$*
							// is extra provider info
							fDtraceProviderInfo.push_back(undefinedName);
						}
					}
				}
			}
		}
	}
	
	// add relocation based references to sections that have atoms with pending names
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		if ( fSectionsWithAtomsPendingAName.count(sect) != 0 )
			addReferencesForSection(sect);
	}
	
	// update any anonymous atoms that need references built in order to name themselves
	for (typename std::vector<AnonymousAtom<A>*>::iterator it=fAtomsPendingAName.begin(); it != fAtomsPendingAName.end(); it++) {
		(*it)->resolveName();
	}

	// add relocation based references to other sections
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		if ( fSectionsWithAtomsPendingAName.count(sect) == 0 )
			addReferencesForSection(sect);
	}


	// add objective-c references
	if ( fAppleObjc ) {
		for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
			if ( (strcmp(sect->sectname(), "__cls_refs") == 0) && (strcmp(sect->segname(), "__OBJC") == 0) ) {
				for (uint32_t offset = 0; offset < sect->size(); offset += sizeof(pint_t)) {
					AtomAndOffset ao = this->findAtomAndOffset(sect->addr()+offset);
					ObjectFile::Reference* classRef = ao.atom->getReferences()[0];
					if ( classRef->getFixUpOffset() == 0 ) {
						const char* classStr = classRef->getTargetName();
						if ( strncmp(classStr, "cstring=", 8) == 0 ) {
							const char* className;
							asprintf((char**)&className, ".objc_class_name_%s", &classStr[8]);
							new Reference<A>(A::kNoFixUp, ao, className, 0);
						}
					}
				}
			}
		}
	}

	// add direct references to local non-lazy-pointers, can do this now that all atoms are constructed
	for (typename std::vector<AnonymousAtom<A>*>::iterator it=fLocalNonLazys.begin(); it != fLocalNonLazys.end(); it++) {
		AnonymousAtom<A>* localNonLazy = *it;
		uint32_t fileOffset = localNonLazy->fSection->offset() - localNonLazy->fSection->addr() + localNonLazy->fAddress;
		pint_t nonLazyPtrValue = P::getP(*((pint_t*)((char*)(fHeader)+fileOffset)));
		makeReference(A::kPointer, localNonLazy->fAddress, nonLazyPtrValue);
	}
	
	// add implicit direct reference from each C++ function to its eh info
	for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
		if ( ((sect->flags() & SECTION_TYPE) == S_COALESCED) && (strcmp(sect->sectname(), "__eh_frame") == 0) ) {
			for (std::map<uint32_t, BaseAtom*>::iterator it=fAddrToAtom.begin(); it != fAddrToAtom.end(); it++) {
				// note: this algorithm depens on the map iterator returning entries in address order
				if ( (it->first >= sect->addr()) && (it->first < sect->addr()+sect->size()) ) {
					uint32_t ehAtomAddress = it->first;
					BaseAtom* ehAtom = it->second;
					const char* ehName = ehAtom->getName();
					if ( (ehName != NULL) && (strcmp(&ehName[strlen(ehName)-3], ".eh") == 0) ) 
						makeReferenceToEH(ehName, ehAtomAddress, sect);
				}
			}
		}
	}

	// add command line aliases
	for(std::vector<ObjectFile::ReaderOptions::AliasPair>::const_iterator it = fOptions.fAliases.begin(); it != fOptions.fAliases.end(); ++it) { 
		BaseAtom* target = this->findAtomByName(it->realName);
		if ( (target != NULL) && target->getSymbolTableInclusion() != ObjectFile::Atom::kSymbolTableNotIn )
			fAtoms.push_back(new SymbolAliasAtom<A>(it->alias, NULL, *target));
	}

	// add dtrace probe locations
	if ( fHasDTraceProbes ) {
		for (uint32_t i=0; i < fSymbolCount; ++i) {
			const macho_nlist<P>& sym = fSymbols[i];
			if ( (sym.n_type() & N_STAB) == 0 ) {
				if ( (sym.n_type() & N_TYPE) == N_SECT ) {
					const char* symbolName = &fStrings[sym.n_strx()];
					if ( strncmp(symbolName, "__dtrace_probe$", 15) == 0 ) {
						//fprintf(stderr, "adding dtrace probe at 0x%08llX %s\n", sym.n_value(), symbolName);
						makeByNameReference(A::kDtraceProbe, sym.n_value(), symbolName, 0);
					}
				}
			}
		}
	}
	
	// turn indirect symbols int SymbolAliasAtom 
	if ( fHaveIndirectSymbols ) {
		for (uint32_t i=0; i < fSymbolCount; ++i) {
			const macho_nlist<P>& sym = fSymbols[i];
			if ( (sym.n_type() & N_STAB) == 0 ) {
				if ( (sym.n_type() & N_TYPE) == N_INDR ) {
					const char* aliasName = &fStrings[sym.n_strx()];
					const char* targetName = &fStrings[sym.n_value()];
					//fprintf(stderr, "found alias %s for %s\n", aliasName, targetName);
					BaseAtom* target = this->findAtomByName(targetName);
					// only currently support N_INDR based aliases to something in the same .o file 
					if ( target != NULL ) {
						fAtoms.push_back(new SymbolAliasAtom<A>(aliasName, &sym, *target));
						//fprintf(stderr, "creating alias %s for %s\n", aliasName, targetName);
					}
				}
			}
		}
	}

	//for (std::map<uint32_t, BaseAtom*>::iterator it=fAddrToAtom.begin(); it != fAddrToAtom.end(); it++) {
	//	fprintf(stderr, "[0x%0X -> 0x%0llX) : %s\n", it->first, it->first+it->second->getSize(), it->second->getDisplayName());
	//}

	// add translation unit info from dwarf
	uint64_t stmtList;
	if ( (fDebugInfo == kDebugInfoDwarf) && (fOptions.fDebugInfoStripping != ObjectFile::ReaderOptions::kDebugInfoNone) ) {
		// compiler sometimes emits emtpty dwarf sections when there is no debug info, skip those
		if ( (fDwarfDebugInfoSect != NULL) && (fDwarfDebugInfoSect->size() != 0) ) {
			if ( !read_comp_unit(&fDwarfTranslationUnitFile, &fDwarfTranslationUnitDir, &stmtList) ) {
				// if can't parse dwarf, warn and give up
				fDwarfTranslationUnitFile = NULL;
				fDwarfTranslationUnitDir = NULL;
				fprintf(stderr, "ld: warning can't parse dwarf compilation unit info in %s\n", this->getPath());
				fDebugInfo = kDebugInfoNone;
			}
		}
	}

	// add line number info to atoms from dwarf
	if ( (fDebugInfo == kDebugInfoDwarf) && (fOptions.fDebugInfoStripping != ObjectFile::ReaderOptions::kDebugInfoNone) ) {
		// file with just data will have no __debug_line info
		if ( (fDwarfDebugLineSect != NULL) && (fDwarfDebugLineSect->size() != 0) && (fAddrToAtom.size() != 0)
			&& (fDwarfDebugInfoSect != NULL) && (fDwarfDebugInfoSect->size() != 0) ) {
			// validate stmt_list
			if ( (stmtList != (uint64_t)-1) && (stmtList < fDwarfDebugLineSect->size()) ) {
				const uint8_t* debug_line = (uint8_t*)(fHeader) + fDwarfDebugLineSect->offset();
				if ( debug_line != NULL ) {
					struct line_reader_data* lines = line_open(&debug_line[stmtList],
															fDwarfDebugLineSect->size() - stmtList, E::little_endian);
					struct line_info result;
					ObjectFile::Atom* curAtom = NULL;
					uint32_t curAtomOffset = 0;
					uint32_t curAtomAddress = 0;
					uint32_t curAtomSize = 0;
					while ( line_next (lines, &result, line_stop_pc) ) {
						//fprintf(stderr, "curAtom=%p, result.pc=0x%llX, result.line=%llu, result.end_of_sequence=%d, curAtomAddress=0x%X, curAtomSize=0x%X\n",
						//		curAtom, result.pc, result.line, result.end_of_sequence, curAtomAddress, curAtomSize);
						// work around weird debug line table compiler generates if no functions in __text section
						if ( (curAtom == NULL) && (result.pc == 0) && result.end_of_sequence && (result.file == 1))
							continue;
						// for performance, see if in next pc is in current atom
						if ( (curAtom != NULL) && (curAtomAddress <= result.pc) && (result.pc < (curAtomAddress+curAtomSize)) ) {
							curAtomOffset = result.pc - curAtomAddress;
						}
						// or pc at end of current atom
						else if ( result.end_of_sequence && (curAtom != NULL) && (result.pc == (curAtomAddress+curAtomSize)) ) {
							curAtomOffset = result.pc - curAtomAddress;
						}
						else {
							// do slow look up of atom by address
							AtomAndOffset ao = this->findAtomAndOffset(result.pc);
							curAtom			= ao.atom;
							if ( curAtom == NULL )
								break; // file has line info but no functions
							if ( result.end_of_sequence && (curAtomAddress+curAtomSize < result.pc) ) {	
								// a one line function can be returned by line_next() as one entry with pc at end of blob
								// look for alt atom starting at end of previous atom
								uint32_t previousEnd = curAtomAddress+curAtomSize;
								AtomAndOffset alt = this->findAtomAndOffset(previousEnd);
								if ( result.pc <= previousEnd - alt.offset + alt.atom->getSize() ) {
									curAtom			= alt.atom;
									curAtomOffset	= alt.offset;
									curAtomAddress	= previousEnd - alt.offset;
									curAtomSize		= curAtom->getSize();
								}
								else {
									curAtomOffset	= ao.offset;
									curAtomAddress	= result.pc - ao.offset;
									curAtomSize		= curAtom->getSize();
								}
							}
							else {
								curAtomOffset	= ao.offset;
								curAtomAddress	= result.pc - ao.offset;
								curAtomSize		= curAtom->getSize();
							}
						}
						const char* filename;
						std::map<uint32_t,const char*>::iterator pos = fDwarfIndexToFile.find(result.file);
						if ( pos == fDwarfIndexToFile.end() ) {
							filename = line_file(lines, result.file);
							fDwarfIndexToFile[result.file] = filename;
						}
						else {
							filename = pos->second;
						}
						ObjectFile::LineInfo info;
						info.atomOffset = curAtomOffset;
						info.fileName = filename;
						info.lineNumber = result.line;
						//fprintf(stderr, "addr=0x%08llX, line=%lld, file=%s, atom=%s, atom.size=0x%X, end=%d\n", 
						//		result.pc, result.line, filename, curAtom->getDisplayName(), curAtomSize, result.end_of_sequence);
						((BaseAtom*)curAtom)->addLineInfo(info);
						if ( result.end_of_sequence ) {
							curAtom = NULL;
						}
					}
					line_free(lines);
				}
				else {
					fprintf(stderr, "ld: warning could not parse dwarf line number info in %s\n", this->getPath());
				}
			}
		}
	}

	// if no dwarf, try processing stabs debugging info
	if ( (fDebugInfo == kDebugInfoNone) && (fOptions.fDebugInfoStripping != ObjectFile::ReaderOptions::kDebugInfoNone) ) {
		// scan symbol table for stabs entries
		fStabs.reserve(fSymbolCount);  // reduce re-allocations
		BaseAtom* currentAtom = NULL;
		pint_t currentAtomAddress = 0;
		enum { start, inBeginEnd, inFun } state = start;
		for (uint32_t symbolIndex = 0; symbolIndex < fSymbolCount; ++symbolIndex ) {
			const macho_nlist<P>* sym = &fSymbols[symbolIndex];
			bool useStab = true;
			uint8_t type = sym->n_type();
			const char* symString = (sym->n_strx() != 0) ? &fStrings[sym->n_strx()] : NULL;
			if ( (type & N_STAB) != 0 ) {
				fDebugInfo =  (fHasUUID ? kDebugInfoStabsUUID : kDebugInfoStabs);
				Stab stab;
				stab.atom	= NULL;
				stab.type	= type;
				stab.other	= sym->n_sect();
				stab.desc	= sym->n_desc();
				stab.value	= sym->n_value();
				stab.string = NULL;
				switch (state) {
					case start:
						switch (type) {
							case N_BNSYM:
								// beginning of function block
								state = inBeginEnd;
								// fall into case to lookup atom by addresss
							case N_LCSYM:
							case N_STSYM:
								currentAtomAddress = sym->n_value();
								currentAtom = (BaseAtom*)this->findAtomAndOffset(currentAtomAddress).atom;
								if ( currentAtom != NULL ) {
									stab.atom = currentAtom;
									stab.string = symString;
								}
								else {
									fprintf(stderr, "can't find atom for stabs BNSYM at %08llX in %s\n",
										(uint64_t)sym->n_value(), path);
								}
								break;
							case N_SO:
							case N_OSO:
							case N_OPT:
							case N_LSYM:
							case N_RSYM:
							case N_PSYM:
								// not associated with an atom, just copy
								stab.string = symString;
								break;
							case N_GSYM:
							{
								// n_value field is NOT atom address ;-(
								// need to find atom by name match
								const char* colon = strchr(symString, ':');
								if ( colon != NULL ) {
									// build underscore leading name
									int nameLen = colon - symString;
									char symName[nameLen+2];
									strlcpy(&symName[1], symString, nameLen+1);
									symName[0] = '_';
									symName[nameLen+1] = '\0';
									currentAtom = findAtomByName(symName);
									if ( currentAtom != NULL ) {
										stab.atom = currentAtom;
										stab.string = symString;
									}
								}
								else {
									// might be a debug-note without trailing :G()
									currentAtom = findAtomByName(symString);
									if ( currentAtom != NULL ) {
										stab.atom = currentAtom;
										stab.string = symString;
									}
								}
								if ( stab.atom == NULL ) {
									fprintf(stderr, "can't find atom for N_GSYM stabs %s in %s\n", symString, path);
									useStab = false;
								}
								break;
							}
							case N_FUN:
								// old style stabs without BNSYM
								state = inFun;
								currentAtomAddress = sym->n_value();
								currentAtom = (BaseAtom*)this->findAtomAndOffset(currentAtomAddress).atom;
								if ( currentAtom != NULL ) {
									stab.atom = currentAtom;
									stab.string = symString;
								}
								else {
									fprintf(stderr, "can't find atom for stabs FUN at %08llX in %s\n",
										(uint64_t)currentAtomAddress, path);
								}
								break;
							case N_SOL:
							case N_SLINE:
								stab.string = symString;
								// old stabs
								break;
							case N_BINCL:
							case N_EINCL:
							case N_EXCL:
								stab.string = symString;
								// -gfull built .o file
								break;
							default:
								fprintf(stderr, "unknown stabs type 0x%X in %s\n", type, path);
						}
						break;
					case inBeginEnd:
						stab.atom = currentAtom;
						switch (type) {
							case N_ENSYM:
								state = start;
								currentAtom = NULL;
								break;
							case N_LCSYM:
							case N_STSYM:
							{
								BaseAtom* nestedAtom = (BaseAtom*)this->findAtomAndOffset(sym->n_value()).atom;
								if ( nestedAtom != NULL ) {
									stab.atom = nestedAtom;
									stab.string = symString;
								}
								else {
									fprintf(stderr, "can't find atom for stabs 0x%X at %08llX in %s\n",
										type, (uint64_t)sym->n_value(), path);
								}
								break;
							}
							case N_LBRAC:
							case N_RBRAC:
							case N_SLINE:
								// adjust value to be offset in atom
								stab.value -= currentAtomAddress;
							default:
								stab.string = symString;
								break;
						}
						break;
					case inFun:
						switch (type) {
							case N_FUN:
								if ( sym->n_sect() != 0 ) {
									// found another start stab, must be really old stabs...
									currentAtomAddress = sym->n_value();
									currentAtom = (BaseAtom*)this->findAtomAndOffset(currentAtomAddress).atom;
									if ( currentAtom != NULL ) {
										stab.atom = currentAtom;
										stab.string = symString;
									}
									else {
										fprintf(stderr, "can't find atom for stabs FUN at %08llX in %s\n",
											(uint64_t)currentAtomAddress, path);
									}
								}
								else {
									// found ending stab, switch back to start state
									stab.string = symString;
									stab.atom = currentAtom;
									state = start;
									currentAtom = NULL;
								}
								break;
							case N_LBRAC:
							case N_RBRAC:
							case N_SLINE:
								// adjust value to be offset in atom
								stab.value -= currentAtomAddress;
								stab.atom = currentAtom;
								break;
							case N_SO:
								stab.string = symString;
								state = start;
								break;
							default:
								stab.atom = currentAtom;
								stab.string = symString;
								break;
						}
						break;
				}
				// add to list of stabs for this .o file
				if ( useStab )
					fStabs.push_back(stab);
			}
		}
	}

#if 0
	// special case precompiled header .o file (which has no content) to have one empty atom
	if ( fAtoms.size() == 0 ) {
		int pathLen = strlen(path);
		if ( (pathLen > 6) && (strcmp(&path[pathLen-6], ".gch.o")==0) ) {
			ObjectFile::Atom* phony = new AnonymousAtom<A>(*this, (uint32_t)0);
			//phony->fSynthesizedName = ".gch.o";
			fAtoms.push_back(phony);
		}
	}
#endif

	// sort all atoms by address
	std::sort(fAtoms.begin(), fAtoms.end(), BaseAtomSorter());

	// set ordinal and sort references in each atom
	uint32_t index = fOrdinalBase;
	for (std::vector<BaseAtom*>::iterator it=fAtoms.begin(); it != fAtoms.end(); it++) {
		BaseAtom* atom = (BaseAtom*)(*it);
		atom->setOrdinal(index++);
		atom->sortReferences();
	}
	
}


template <>
void Reader<ppc>::setCpuConstraint(uint32_t cpusubtype)
{
	switch (cpusubtype) {
		case CPU_SUBTYPE_POWERPC_ALL:
			fCpuConstraint = ObjectFile::Reader::kCpuAny;
			break;
		case CPU_SUBTYPE_POWERPC_750:
			fCpuConstraint = ObjectFile::Reader::kCpuG3;
			break;
		case CPU_SUBTYPE_POWERPC_7400:
		case CPU_SUBTYPE_POWERPC_7450:
			fCpuConstraint = ObjectFile::Reader::kCpuG4;
			break;
		case CPU_SUBTYPE_POWERPC_970:
			fCpuConstraint = ObjectFile::Reader::kCpuG5;
			break;
		default:
			fprintf(stderr, "ld: warning, unknown cpu-sub-type 0x%08X in %s\n", cpusubtype, fPath);
	}
}


template <typename A>
void Reader<A>::setCpuConstraint(uint32_t cpusubtype)
{
	// no cpu sub types for this architecture
}

template <typename A>
void Reader<A>::addDtraceExtraInfos(uint32_t probeAddr, const char* providerName)
{
	// for every ___dtrace_stability$* and ___dtrace_typedefs$* undefine with
	// a matching provider name, add a by-name kDtraceTypeReference at probe site
 	const char* dollar = strchr(providerName, '$');
	if ( dollar != NULL ) {
		int providerNameLen = dollar-providerName+1;
		for ( std::vector<const char*>::iterator it = fDtraceProviderInfo.begin(); it != fDtraceProviderInfo.end(); ++it) {
			const char* typeDollar = strchr(*it, '$');
			if ( typeDollar != NULL ) {
				if ( strncmp(typeDollar+1, providerName, providerNameLen) == 0 ) {
					makeByNameReference(A::kDtraceTypeReference, probeAddr, *it, 0);
				}
			}
		}
	}
}


template <>
void Reader<x86_64>::validSectionType(uint8_t type)
{
	switch ( type ) {
		case S_SYMBOL_STUBS:
			throw "symbol_stub sections not valid in x86_64 object files";
		case S_LAZY_SYMBOL_POINTERS:
			throw "lazy pointer sections not valid in x86_64 object files";
		case S_NON_LAZY_SYMBOL_POINTERS:
			throw "non lazy pointer sections not valid in x86_64 object files";
	}
}

template <typename A>
void Reader<A>::validSectionType(uint8_t type)
{
}

template <typename A>
bool Reader<A>::getTranslationUnitSource(const char** dir, const char** name) const
{
	if ( fDebugInfo == kDebugInfoDwarf ) {
		*dir = fDwarfTranslationUnitDir;
		*name = fDwarfTranslationUnitFile;
		return (fDwarfTranslationUnitFile != NULL);
	}
	return false;
}

template <typename A>
BaseAtom* Reader<A>::findAtomByName(const char* name)
{
	// first search the more important atoms
	for (std::map<uint32_t, BaseAtom*>::iterator it=fAddrToAtom.begin(); it != fAddrToAtom.end(); it++) {
		const char* atomName = it->second->getName();
		if ( (atomName != NULL) && (strcmp(atomName, name) == 0) ) {
			return it->second;
		}
	}
	// try all atoms, because this might have been a tentative definition
	for (std::vector<BaseAtom*>::iterator it=fAtoms.begin(); it != fAtoms.end(); it++) {
		BaseAtom* atom = (BaseAtom*)(*it);
		const char* atomName = atom->getName();
		if ( (atomName != NULL) && (strcmp(atomName, name) == 0) ) {
			return atom;
		}
	}
	return NULL;
}

template <typename A>
Reference<A>* Reader<A>::makeReference(Kinds kind, uint32_t atAddr, uint32_t toAddr)
{
	return new Reference<A>(kind, findAtomAndOffset(atAddr), findAtomAndOffset(toAddr));
}

template <typename A>
Reference<A>* Reader<A>::makeReference(Kinds kind, uint32_t atAddr, uint32_t fromAddr, uint32_t toAddr)
{
	return new Reference<A>(kind, findAtomAndOffset(atAddr), findAtomAndOffset(fromAddr), findAtomAndOffset(toAddr));
}

template <typename A>
Reference<A>* Reader<A>::makeReferenceWithToBase(Kinds kind, uint32_t atAddr, uint32_t toAddr, uint32_t toBaseAddr)
{
	return new Reference<A>(kind, findAtomAndOffset(atAddr), findAtomAndOffset(toBaseAddr, toAddr));
}

template <typename A>
Reference<A>* Reader<A>::makeReferenceWithToBase(Kinds kind, uint32_t atAddr, uint32_t fromAddr, uint32_t toAddr, uint32_t toBaseAddr)
{
	return new Reference<A>(kind, findAtomAndOffset(atAddr), findAtomAndOffset(fromAddr), findAtomAndOffset(toBaseAddr, toAddr));
}

template <typename A>
Reference<A>* Reader<A>::makeByNameReference(Kinds kind, uint32_t atAddr, const char* toName, uint32_t toOffset)
{
	return new Reference<A>(kind, findAtomAndOffset(atAddr), toName, toOffset);
}

template <typename A>
Reference<A>* Reader<A>::makeReferenceToEH(const char* ehName, pint_t ehAtomAddress, const macho_section<P>* ehSect)
{
	// add a direct reference from function atom to its eh frame atom
	const uint8_t* ehContent = (const uint8_t*)(fHeader) + ehAtomAddress - ehSect->addr() + ehSect->offset();
	int32_t deltaMinus8 = P::getP(*(pint_t*)(&ehContent[8]));	// offset 8 in eh info is delta to function
	uint32_t funcAddr = ehAtomAddress + deltaMinus8 + 8;
	return makeReference(A::kNoFixUp, funcAddr, ehAtomAddress);
}


template <>
Reference<x86_64>* Reader<x86_64>::makeByNameReference(Kinds kind, uint32_t atAddr, const char* toName, uint32_t toOffset)
{
	// x86_64 uses external relocations everywhere, so external relocations do not imply by-name references
	// instead check scope of target
	BaseAtom* target = findAtomByName(toName);
	if ( (target != NULL) && (target->getScope() == ObjectFile::Atom::scopeTranslationUnit) )
		return new Reference<x86_64>(kind, findAtomAndOffset(atAddr), AtomAndOffset(target, toOffset));
	else
		return new Reference<x86_64>(kind, findAtomAndOffset(atAddr), toName, toOffset);
}

template <>
Reference<x86_64>* Reader<x86_64>::makeReferenceToSymbol(Kinds kind, uint32_t atAddr, const macho_nlist<P>* toSymbol, uint32_t toOffset)
{
	// x86_64 uses external relocations everywhere, so external relocations do not imply by-name references
	// instead check scope of target
	const char* symbolName = &fStrings[toSymbol->n_strx()];
	if ( ((toSymbol->n_type() & N_TYPE) == N_SECT) && (((toSymbol->n_type() & N_EXT) == 0) || (symbolName[0] == 'L')) ) 
		return new Reference<x86_64>(kind, findAtomAndOffset(atAddr), findAtomAndOffset(toSymbol->n_value(), toSymbol->n_value()+toOffset));
	else
		return new Reference<x86_64>(kind, findAtomAndOffset(atAddr), symbolName, toOffset);
}


template <>
Reference<x86_64>* Reader<x86_64>::makeReferenceToEH(const char* ehName, pint_t ehAtomAddress, const macho_section<P>* ehSect)
{
	// add a direct reference from function atom to its eh frame atom
	// for x86_64 the __eh_frame section contains the addends, so need to use relocs to find target
	uint32_t ehAtomDeltaSectionOffset = ehAtomAddress + 8 - ehSect->addr(); // offset 8 in eh info is delta to function
	const macho_relocation_info<P>* relocs = (macho_relocation_info<P>*)((char*)(fHeader) + ehSect->reloff());
	const macho_relocation_info<P>* relocsEnd = &relocs[ehSect->nreloc()];
	for (const macho_relocation_info<P>* reloc = relocs; reloc < relocsEnd; ++reloc) {
		if ( (reloc->r_address() == ehAtomDeltaSectionOffset) && (reloc->r_type() == X86_64_RELOC_UNSIGNED) ) {
			uint32_t funcAddr = fSymbols[reloc->r_symbolnum()].n_value();
			return makeReference(x86_64::kNoFixUp, funcAddr, ehAtomAddress);
		}
	}
	fprintf(stderr, "ld: warning, can't find matching function for eh symbol %s\n", ehName);
	return NULL;
}


template <typename A>
AtomAndOffset Reader<A>::findAtomAndOffset(uint32_t addr)
{
	// STL has no built-in for "find largest key that is same or less than"
	std::map<uint32_t, BaseAtom*>::iterator it = fAddrToAtom.upper_bound(addr);
	--it; // upper_bound gets us next key, so we back up one
	AtomAndOffset result;
	result.atom = it->second;
	result.offset = addr - it->first;
	//fprintf(stderr, "findAtomAndOffset(0x%0X) ==> %s (0x%0X -> 0x%0llX)\n",
	//			addr, result.atom->getDisplayName(), it->first, it->first+result.atom->getSize());
	return result;
}

// "scattered" relocations enable you to offset into an atom past the end of it
// baseAddr is the address of the target atom,
// realAddr is the points into it
template <typename A>
AtomAndOffset Reader<A>::findAtomAndOffset(uint32_t baseAddr, uint32_t realAddr)
{
	std::map<uint32_t, BaseAtom*>::iterator it = fAddrToAtom.find(baseAddr);
	if ( it != fAddrToAtom.end() ) {
		AtomAndOffset result;
		result.atom = it->second;
		result.offset = realAddr - it->first;
		//fprintf(stderr, "findAtomAndOffset(0x%08X, 0x%08X) => %s + 0x%08X\n", baseAddr, realAddr, result.atom->getDisplayName(), result.offset);
		return result;
	}
	// getting here means we have a scattered relocation to an address without a label
	// we should never get here...
	// one case we do get here is because sometimes the compiler generates non-lazy pointers in the __data section
	return findAtomAndOffset(realAddr);
}


/* Skip over a LEB128 value (signed or unsigned).  */
static void
skip_leb128 (const uint8_t ** offset, const uint8_t * end)
{
  while (*offset != end && **offset >= 0x80)
    (*offset)++;
  if (*offset != end)
    (*offset)++;
}

/* Read a ULEB128 into a 64-bit word.  Return (uint64_t)-1 on overflow
   or error.  On overflow, skip past the rest of the uleb128.  */
static uint64_t
read_uleb128 (const uint8_t ** offset, const uint8_t * end)
{
  uint64_t result = 0;
  int bit = 0;

  do  {
    uint64_t b;

    if (*offset == end)
      return (uint64_t) -1;

    b = **offset & 0x7f;

    if (bit >= 64 || b << bit >> bit != b)
      result = (uint64_t) -1;
    else
      result |= b << bit, bit += 7;
  } while (*(*offset)++ >= 0x80);
  return result;
}


/* Skip over a DWARF attribute of form FORM.  */
template <typename A>
bool Reader<A>::skip_form(const uint8_t ** offset, const uint8_t * end, uint64_t form,
							uint8_t addr_size, bool dwarf64)
{
  int64_t sz=0;

  switch (form)
    {
    case DW_FORM_addr:
      sz = addr_size;
      break;

    case DW_FORM_block2:
      if (end - *offset < 2)
	return false;
      sz = 2 + A::P::E::get16(*(uint16_t*)offset);
      break;

    case DW_FORM_block4:
      if (end - *offset < 4)
	return false;
      sz = 2 + A::P::E::get32(*(uint32_t*)offset);
      break;

    case DW_FORM_data2:
    case DW_FORM_ref2:
      sz = 2;
      break;

    case DW_FORM_data4:
    case DW_FORM_ref4:
      sz = 4;
      break;

    case DW_FORM_data8:
    case DW_FORM_ref8:
      sz = 8;
      break;

    case DW_FORM_string:
      while (*offset != end && **offset)
	++*offset;
    case DW_FORM_data1:
    case DW_FORM_flag:
    case DW_FORM_ref1:
      sz = 1;
      break;

    case DW_FORM_block:
      sz = read_uleb128 (offset, end);
      break;

    case DW_FORM_block1:
      if (*offset == end)
	return false;
      sz = 1 + **offset;
      break;

    case DW_FORM_sdata:
    case DW_FORM_udata:
    case DW_FORM_ref_udata:
      skip_leb128 (offset, end);
      return true;

    case DW_FORM_strp:
    case DW_FORM_ref_addr:
      sz = dwarf64 ? 8 : 4;
      break;

    default:
      return false;
    }
  if (end - *offset < sz)
    return false;
  *offset += sz;
  return true;
}

// Look at the compilation unit DIE and determine
// its NAME, compilation directory (in COMP_DIR) and its
// line number information offset (in STMT_LIST).  NAME and COMP_DIR
// may be NULL (especially COMP_DIR) if they are not in the .o file;
// STMT_LIST will be (uint64_t) -1.
//
// At present this assumes that there's only one compilation unit DIE.
//
template <typename A>
bool Reader<A>::read_comp_unit(const char ** name, const char ** comp_dir,
							uint64_t *stmt_list)
{
	const uint8_t * debug_info;
	const uint8_t * debug_abbrev;
	const uint8_t * di;
	const uint8_t * da;
	const uint8_t * end;
	const uint8_t * enda;
	uint64_t sz;
	uint16_t vers;
	uint64_t abbrev_base;
	uint64_t abbrev;
	uint8_t address_size;
	bool dwarf64;

	*name = NULL;
	*comp_dir = NULL;
	*stmt_list = (uint64_t) -1;

	if ( (fDwarfDebugInfoSect == NULL) || (fDwarfDebugAbbrevSect == NULL) )
		return false;

	debug_info = (uint8_t*)(fHeader) + fDwarfDebugInfoSect->offset();
	debug_abbrev = (uint8_t*)(fHeader) + fDwarfDebugAbbrevSect->offset();
	di = debug_info;

	if (fDwarfDebugInfoSect->size() < 12)
		/* Too small to be a real debug_info section.  */
		return false;
	sz = A::P::E::get32(*(uint32_t*)di);
	di += 4;
	dwarf64 = sz == 0xffffffff;
	if (dwarf64)
		sz = A::P::E::get64(*(uint64_t*)di), di += 8;
	else if (sz > 0xffffff00)
		/* Unknown dwarf format.  */
		return false;

	/* Verify claimed size.  */
	if (sz + (di - debug_info) > fDwarfDebugInfoSect->size() || sz <= (dwarf64 ? 23 : 11))
		return false;

	vers = A::P::E::get16(*(uint16_t*)di);
	if (vers < 2 || vers > 3)
	/* DWARF version wrong for this code.
	   Chances are we could continue anyway, but we don't know for sure.  */
		return false;
	di += 2;

	/* Find the debug_abbrev section.  */
	abbrev_base = dwarf64 ? A::P::E::get64(*(uint64_t*)di) : A::P::E::get32(*(uint32_t*)di);
	di += dwarf64 ? 8 : 4;

	if (abbrev_base > fDwarfDebugAbbrevSect->size())
		return false;
	da = debug_abbrev + abbrev_base;
	enda = debug_abbrev + fDwarfDebugAbbrevSect->size();

	address_size = *di++;

	/* Find the abbrev number we're looking for.  */
	end = di + sz;
	abbrev = read_uleb128 (&di, end);
	if (abbrev == (uint64_t) -1)
		return false;

	/* Skip through the debug_abbrev section looking for that abbrev.  */
	for (;;)
	{
		uint64_t this_abbrev = read_uleb128 (&da, enda);
		uint64_t attr;

		if (this_abbrev == abbrev)
			/* This is almost always taken.  */
			break;
		skip_leb128 (&da, enda); /* Skip the tag.  */
		if (da == enda)
			return false;
		da++;  /* Skip the DW_CHILDREN_* value.  */

		do {
			attr = read_uleb128 (&da, enda);
			skip_leb128 (&da, enda);
		} while (attr != 0 && attr != (uint64_t) -1);
		if (attr != 0)
			return false;
	}

	/* Check that the abbrev is one for a DW_TAG_compile_unit.  */
	if (read_uleb128 (&da, enda) != DW_TAG_compile_unit)
	return false;
	if (da == enda)
	return false;
	da++;  /* Skip the DW_CHILDREN_* value.  */

	/* Now, go through the DIE looking for DW_AT_name,
	 DW_AT_comp_dir, and DW_AT_stmt_list.  */
	for (;;)
	{
		uint64_t attr = read_uleb128 (&da, enda);
		uint64_t form = read_uleb128 (&da, enda);

		if (attr == (uint64_t) -1)
			return false;
		else if (attr == 0)
			return true;

		if (form == DW_FORM_indirect)
			form = read_uleb128 (&di, end);

		if (attr == DW_AT_name && form == DW_FORM_string)
			*name = (const char *) di;
		else if (attr == DW_AT_comp_dir && form == DW_FORM_string)
			*comp_dir = (const char *) di;
		/* Really we should support DW_FORM_strp here, too, but
		there's usually no reason for the producer to use that form
		 for the DW_AT_name and DW_AT_comp_dir attributes.  */
		else if (attr == DW_AT_stmt_list && form == DW_FORM_data4)
			*stmt_list = A::P::E::get32(*(uint32_t*)di);
		else if (attr == DW_AT_stmt_list && form == DW_FORM_data8)
			*stmt_list = A::P::E::get64(*(uint64_t*)di);
		if (! skip_form (&di, end, form, address_size, dwarf64))
			return false;
	}
}

template <typename A>
const char* Reader<A>::assureFullPath(const char* path)
{
	if ( path[0] == '/' )
		return path;
	char cwdbuff[MAXPATHLEN];
	if ( getcwd(cwdbuff, MAXPATHLEN) != NULL ) {
		char* result;
		asprintf(&result, "%s/%s", cwdbuff, path);
		if ( result != NULL )
			return result;
	}
	return path;
}


//
//
//	To implement architecture xxx, you must write template specializations for the following six methods:
//			Reader<xxx>::validFile()
//			Reader<xxx>::addRelocReference()
//			Reference<xxx>::getDescription()
//
//


template <>
bool Reader<ppc>::validFile(const uint8_t* fileContent)
{
	const macho_header<P>* header = (const macho_header<P>*)fileContent;
	if ( header->magic() != MH_MAGIC )
		return false;
	if ( header->cputype() != CPU_TYPE_POWERPC )
		return false;
	if ( header->filetype() != MH_OBJECT )
		return false;
	return true;
}

template <>
bool Reader<ppc64>::validFile(const uint8_t* fileContent)
{
	const macho_header<P>* header = (const macho_header<P>*)fileContent;
	if ( header->magic() != MH_MAGIC_64 )
		return false;
	if ( header->cputype() != CPU_TYPE_POWERPC64 )
		return false;
	if ( header->filetype() != MH_OBJECT )
		return false;
	return true;
}

template <>
bool Reader<x86>::validFile(const uint8_t* fileContent)
{
	const macho_header<P>* header = (const macho_header<P>*)fileContent;
	if ( header->magic() != MH_MAGIC )
		return false;
	if ( header->cputype() != CPU_TYPE_I386 )
		return false;
	if ( header->filetype() != MH_OBJECT )
		return false;
	return true;
}

template <>
bool Reader<x86_64>::validFile(const uint8_t* fileContent)
{
	const macho_header<P>* header = (const macho_header<P>*)fileContent;
	if ( header->magic() != MH_MAGIC_64 )
		return false;
	if ( header->cputype() != CPU_TYPE_X86_64 )
		return false;
	if ( header->filetype() != MH_OBJECT )
		return false;
	return true;
}


template <typename A>
bool Reader<A>::isWeakImportSymbol(const macho_nlist<P>* sym)
{
	return ( ((sym->n_type() & N_TYPE) == N_UNDF) && ((sym->n_desc() & N_WEAK_REF) != 0) );
}

template <>
bool Reader<ppc64>::addRelocReference(const macho_section<ppc64::P>* sect, const macho_relocation_info<ppc64::P>* reloc)
{
	return addRelocReference_powerpc(sect, reloc);
}

template <>
bool Reader<ppc>::addRelocReference(const macho_section<ppc::P>* sect, const macho_relocation_info<ppc::P>* reloc)
{
	return addRelocReference_powerpc(sect, reloc);
}


//
// ppc and ppc64 both use the same relocations, so process them in one common routine
//
template <typename A>
bool Reader<A>::addRelocReference_powerpc(const macho_section<typename A::P>* sect,
										  const macho_relocation_info<typename A::P>* reloc)
{
	uint32_t srcAddr;
	uint32_t dstAddr;
	uint32_t* fixUpPtr;
	int32_t displacement = 0;
	uint32_t instruction = 0;
	uint32_t offsetInTarget;
	int16_t lowBits;
	bool result = false;
	if ( (reloc->r_address() & R_SCATTERED) == 0 ) {
		const macho_relocation_info<P>* nextReloc = &reloc[1];
		const char* targetName = NULL;
		bool weakImport = false;
		fixUpPtr = (uint32_t*)((char*)(fHeader) + sect->offset() + reloc->r_address());
		if ( reloc->r_type() != PPC_RELOC_PAIR )
			instruction = BigEndian::get32(*fixUpPtr);
		srcAddr = sect->addr() + reloc->r_address();
		if ( reloc->r_extern() ) {
			const macho_nlist<P>* targetSymbol = &fSymbols[reloc->r_symbolnum()];
			targetName = &fStrings[targetSymbol->n_strx()];
			weakImport = this->isWeakImportSymbol(targetSymbol);
		}
		switch ( reloc->r_type() ) {
			case PPC_RELOC_BR24:
				{
					if ( (instruction & 0x4C000000) == 0x48000000 ) {
						displacement = (instruction & 0x03FFFFFC);
						if ( (displacement & 0x02000000) != 0 )
							displacement |= 0xFC000000;
					}
					else {
						printf("bad instruction for BR24 reloc");
					}
					if ( reloc->r_extern() ) {
						offsetInTarget = srcAddr + displacement;
						if ( strncmp(targetName, "___dtrace_probe$", 16) == 0 ) {
							makeByNameReference(A::kDtraceProbeSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[16]);
						}
						else if ( strncmp(targetName, "___dtrace_isenabled$", 20) == 0 ) {
							makeByNameReference(A::kDtraceIsEnabledSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[20]);
						}
						else if ( weakImport )
							makeByNameReference(A::kBranch24WeakImport, srcAddr, targetName, offsetInTarget);
						else
							makeByNameReference(A::kBranch24, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = srcAddr + displacement;
						// if this is a branch to a stub, we need to see if the stub is for a weak imported symbol
						ObjectFile::Atom* atom = findAtomAndOffset(dstAddr).atom;
						targetName = atom->getName();
						if ( (targetName != NULL) && (strncmp(targetName, "___dtrace_probe$", 16) == 0) ) {
							makeByNameReference(A::kDtraceProbeSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[16]);
						}
						else if ( (targetName != NULL) && (strncmp(targetName, "___dtrace_isenabled$", 20) == 0) ) {
							makeByNameReference(A::kDtraceIsEnabledSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[20]);
						}
						else if ( (atom->getSymbolTableInclusion() == ObjectFile::Atom::kSymbolTableNotIn)
							&& ((AnonymousAtom<A>*)atom)->isWeakImportStub() )
							makeReference(A::kBranch24WeakImport, srcAddr, dstAddr);
						else
							makeReference(A::kBranch24, srcAddr, dstAddr);
					}
				}
				break;
			case PPC_RELOC_BR14:
				{
					displacement = (instruction & 0x0000FFFC);
					if ( (displacement & 0x00008000) != 0 )
						displacement |= 0xFFFF0000;
					if ( reloc->r_extern() ) {
						offsetInTarget = srcAddr + displacement;
						makeByNameReference(A::kBranch14, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = srcAddr + displacement;
						makeReference(A::kBranch14, srcAddr, dstAddr);
					}
				}
				break;
			case PPC_RELOC_PAIR:
				// skip, processed by a previous look ahead
				break;
			case PPC_RELOC_LO16:
				{
					if ( nextReloc->r_type() != PPC_RELOC_PAIR ) {
						printf("PPC_RELOC_LO16 missing following pair\n");
						break;
					}
					result = true;
					lowBits = (instruction & 0xFFFF);
					if ( reloc->r_extern() ) {
						offsetInTarget = (nextReloc->r_address() << 16) | ((uint32_t)lowBits & 0x0000FFFF);
						makeByNameReference(A::kAbsLow16, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = (nextReloc->r_address() << 16) + ((uint32_t)lowBits & 0x0000FFFF);
						if ( reloc->r_symbolnum() == R_ABS ) {
							// find absolute symbol that corresponds to pointerValue
							std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAbsoluteAtom.find(dstAddr);
							if ( pos != fAddrToAbsoluteAtom.end() ) 
								makeByNameReference(A::kAbsLow16, srcAddr, pos->second->getName(), 0);
							else
								makeReference(A::kAbsLow16, srcAddr, dstAddr);
						}
						else {
							makeReference(A::kAbsLow16, srcAddr, dstAddr);
						}
					}
				}
				break;
			case PPC_RELOC_LO14:
				{
					if ( nextReloc->r_type() != PPC_RELOC_PAIR ) {
						printf("PPC_RELOC_LO14 missing following pair\n");
						break;
					}
					result = true;
					lowBits = (instruction & 0xFFFC);
					if ( reloc->r_extern() ) {
						offsetInTarget = (nextReloc->r_address() << 16) | ((uint32_t)lowBits & 0x0000FFFF);
						makeByNameReference(A::kAbsLow14, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = (nextReloc->r_address() << 16) | ((uint32_t)lowBits & 0x0000FFFF);
						if ( reloc->r_symbolnum() == R_ABS ) {
							// find absolute symbol that corresponds to pointerValue
							std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAbsoluteAtom.find(dstAddr);
							if ( pos != fAddrToAbsoluteAtom.end() ) 
								makeByNameReference(A::kAbsLow14, srcAddr, pos->second->getName(), 0);
							else
								makeReference(A::kAbsLow14, srcAddr, dstAddr);
						}
						else {
							makeReference(A::kAbsLow14, srcAddr, dstAddr);
						}
					}
				}
				break;
			case PPC_RELOC_HI16:
				{
					if ( nextReloc->r_type() != PPC_RELOC_PAIR ) {
						printf("PPC_RELOC_HI16 missing following pair\n");
						break;
					}
					result = true;
					if ( reloc->r_extern() ) {
						offsetInTarget = ((instruction & 0x0000FFFF) << 16) | (nextReloc->r_address() & 0x0000FFFF);
						makeByNameReference(A::kAbsHigh16, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = ((instruction & 0x0000FFFF) << 16) | (nextReloc->r_address() & 0x0000FFFF);
						if ( reloc->r_symbolnum() == R_ABS ) {
							// find absolute symbol that corresponds to pointerValue
							std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAbsoluteAtom.find(dstAddr);
							if ( pos != fAddrToAbsoluteAtom.end() ) 
								makeByNameReference(A::kAbsHigh16, srcAddr, pos->second->getName(), 0);
							else
								makeReference(A::kAbsHigh16, srcAddr, dstAddr);
						}
						else {
							makeReference(A::kAbsHigh16, srcAddr, dstAddr);
						}
					}
				}
				break;
			case PPC_RELOC_HA16:
				{
					if ( nextReloc->r_type() != PPC_RELOC_PAIR ) {
						printf("PPC_RELOC_HA16 missing following pair\n");
						break;
					}
					result = true;
					lowBits = (nextReloc->r_address() & 0x0000FFFF);
					if ( reloc->r_extern() ) {
						offsetInTarget = ((instruction & 0x0000FFFF) << 16) + (int32_t)lowBits;
						makeByNameReference(A::kAbsHigh16AddLow, srcAddr, targetName, offsetInTarget);
					}
					else {
						dstAddr = ((instruction & 0x0000FFFF) << 16) + (int32_t)lowBits;
						if ( reloc->r_symbolnum() == R_ABS ) {
							// find absolute symbol that corresponds to pointerValue
							std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAbsoluteAtom.find(dstAddr);
							if ( pos != fAddrToAbsoluteAtom.end() ) 
								makeByNameReference(A::kAbsHigh16AddLow, srcAddr, pos->second->getName(), 0);
							else
								makeReference(A::kAbsHigh16AddLow, srcAddr, dstAddr);
						}
						else {
							makeReference(A::kAbsHigh16AddLow, srcAddr, dstAddr);
						}
					}
				}
				break;
			case PPC_RELOC_VANILLA:
				{
					pint_t pointerValue = P::getP(*((pint_t*)fixUpPtr));
					if ( reloc->r_extern() ) {
						if ( weakImport )
							makeByNameReference(A::kPointerWeakImport, srcAddr, targetName, pointerValue);
						else
							makeByNameReference(A::kPointer, srcAddr, targetName, pointerValue);
					}
					else {
						makeReference(A::kPointer, srcAddr, pointerValue);
					}
				}
				break;
			case PPC_RELOC_JBSR:
				// this is from -mlong-branch codegen.  We ignore the jump island and make reference to the real target
				if ( nextReloc->r_type() != PPC_RELOC_PAIR ) {
					printf("PPC_RELOC_JBSR missing following pair\n");
					break;
				}
				result = true;
				makeReference(A::kBranch24, srcAddr, nextReloc->r_address());
				if ( (instruction & 0x4C000000) == 0x48000000 ) {
					displacement = (instruction & 0x03FFFFFC);
					if ( (displacement & 0x02000000) != 0 )
						displacement |= 0xFC000000;
				}
				else {
					fprintf(stderr, "bad instruction for BR24 reloc");
				}
				if ( reloc->r_extern() ) {
					fprintf(stderr, "PPC_RELOC_JBSR should not be using an external relocation");
				}
				break;
			default:
				printf("unknown relocation type %d\n", reloc->r_type());
		}
	}
	else {
		const macho_scattered_relocation_info<P>* sreloc = (macho_scattered_relocation_info<P>*)reloc;
		srcAddr = sect->addr() + sreloc->r_address();
		dstAddr = sreloc->r_value();
		uint32_t betterDstAddr;
		fixUpPtr = (uint32_t*)((char*)(fHeader) + sect->offset() + sreloc->r_address());
		const macho_scattered_relocation_info<P>* nextSReloc = &sreloc[1];
		const macho_relocation_info<P>* nextReloc = &reloc[1];
		// file format allows pair to be scattered or not
		bool nextRelocIsPair = false;
		uint32_t nextRelocAddress = 0;
		uint32_t nextRelocValue = 0;
		if ( (nextReloc->r_address() & R_SCATTERED) == 0 ) {
			if ( nextReloc->r_type() == PPC_RELOC_PAIR ) {
				nextRelocIsPair = true;
				nextRelocAddress = nextReloc->r_address();
				result = true;
			}
		}
		else {
			if ( nextSReloc->r_type() == PPC_RELOC_PAIR ) {
				nextRelocIsPair = true;
				nextRelocAddress = nextSReloc->r_address();
				nextRelocValue = nextSReloc->r_value();
				result = true;
			}
		}
		switch (sreloc->r_type()) {
			case PPC_RELOC_VANILLA:
				{
					betterDstAddr = P::getP(*(pint_t*)fixUpPtr);
					//fprintf(stderr, "scattered pointer reloc: srcAddr=0x%08X, dstAddr=0x%08X, pointer=0x%08X\n", srcAddr, dstAddr, betterDstAddr);
					// with a scattered relocation we get both the target (sreloc->r_value()) and the target+offset (*fixUpPtr)
					makeReferenceWithToBase(A::kPointer, srcAddr, betterDstAddr, dstAddr);
				}
				break;
			case PPC_RELOC_BR14:
				{
					instruction = BigEndian::get32(*fixUpPtr);
					displacement = (instruction & 0x0000FFFC);
					if ( (displacement & 0x00008000) != 0 )
						displacement |= 0xFFFF0000;
					betterDstAddr = srcAddr+displacement;
					//fprintf(stderr, "betterDstAddr=0x%08X, srcAddr=0x%08X, displacement=0x%08X\n",  betterDstAddr, srcAddr, displacement);
					makeReferenceWithToBase(A::kBranch14, srcAddr, betterDstAddr, dstAddr);
				}
				break;
			case PPC_RELOC_BR24:
				{
					instruction = BigEndian::get32(*fixUpPtr);
					if ( (instruction & 0x4C000000) == 0x48000000 ) {
						displacement = (instruction & 0x03FFFFFC);
						if ( (displacement & 0x02000000) != 0 )
							displacement |= 0xFC000000;
						betterDstAddr = srcAddr+displacement;
						makeReferenceWithToBase(A::kBranch24, srcAddr, betterDstAddr, dstAddr);
					}
				}
				break;
			case PPC_RELOC_LO16_SECTDIFF:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_LO16_SECTDIFF missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (instruction & 0xFFFF);
					displacement = (nextRelocAddress << 16) | ((uint32_t)lowBits & 0x0000FFFF);
					makeReferenceWithToBase(A::kPICBaseLow16, srcAddr, nextRelocValue, nextRelocValue + displacement, dstAddr);
				}
				break;
			case PPC_RELOC_LO14_SECTDIFF:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_LO14_SECTDIFF missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (instruction & 0xFFFC);
					displacement = (nextRelocAddress << 16) | ((uint32_t)lowBits & 0x0000FFFF);
					makeReferenceWithToBase(A::kPICBaseLow14, srcAddr, nextRelocValue, nextRelocValue + displacement, dstAddr);
				}
				break;
			case PPC_RELOC_HA16_SECTDIFF:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_HA16_SECTDIFF missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (nextRelocAddress & 0x0000FFFF);
					displacement = ((instruction & 0x0000FFFF) << 16) + (int32_t)lowBits;
					makeReferenceWithToBase(A::kPICBaseHigh16, srcAddr, nextRelocValue, nextRelocValue + displacement, dstAddr);
				}
				break;
			case PPC_RELOC_LO14:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_LO14 missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (instruction & 0xFFFC);
					betterDstAddr = (nextRelocAddress << 16) + ((uint32_t)lowBits & 0x0000FFFF);
					makeReferenceWithToBase(A::kAbsLow14, srcAddr, betterDstAddr, dstAddr);
				}
				break;
			case PPC_RELOC_LO16:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_LO16 missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (instruction & 0xFFFF);
					betterDstAddr = (nextRelocAddress << 16) + ((uint32_t)lowBits & 0x0000FFFF);
					makeReferenceWithToBase(A::kAbsLow16, srcAddr, betterDstAddr, dstAddr);
				}
				break;
			case PPC_RELOC_HA16:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_HA16 missing following PAIR\n");
						break;
					}
					instruction = BigEndian::get32(*fixUpPtr);
					lowBits = (nextRelocAddress & 0xFFFF);
					betterDstAddr = ((instruction & 0xFFFF) << 16) + (int32_t)lowBits;
					makeReferenceWithToBase(A::kAbsHigh16AddLow, srcAddr, betterDstAddr, dstAddr);
				}
				break;
			case PPC_RELOC_SECTDIFF:
			case PPC_RELOC_LOCAL_SECTDIFF:
				{
					if ( ! nextRelocIsPair ) {
						printf("PPC_RELOC_SECTDIFF missing following pair\n");
						break;
					}
					// need to read section content to see if this has an addend, if so adjust addresses
					switch ( sreloc->r_length() ) {
						case 0:
							if ( (dstAddr - nextRelocValue) != *((uint8_t*)fixUpPtr) ) {
								if (findAtomAndOffset(dstAddr).atom == findAtomAndOffset(srcAddr).atom )
									dstAddr = *((uint8_t*)fixUpPtr) + nextRelocValue;
								else
									nextRelocValue = dstAddr - *((uint8_t*)fixUpPtr);
							}
							break;
						case 1:
							if ( (dstAddr - nextRelocValue) != BigEndian::get16(*((uint16_t*)fixUpPtr)) ) {
								if (findAtomAndOffset(dstAddr).atom == findAtomAndOffset(srcAddr).atom )
									dstAddr = BigEndian::get16(*((uint16_t*)fixUpPtr)) + nextRelocValue;
								else
									nextRelocValue = dstAddr - BigEndian::get16(*((uint16_t*)fixUpPtr));
							}
							break;
						case 2:
							if ( (dstAddr - nextRelocValue) != BigEndian::get32(*fixUpPtr) ) {
								if (findAtomAndOffset(dstAddr).atom == findAtomAndOffset(srcAddr).atom )
									dstAddr = BigEndian::get32(*fixUpPtr) + nextRelocValue;
								else
									nextRelocValue = dstAddr - BigEndian::get32(*fixUpPtr);
							}
							break;
						case 3:
							if ( (dstAddr - nextRelocValue) != BigEndian::get64(*((uint64_t*)fixUpPtr)) ) {
								if (findAtomAndOffset(dstAddr).atom == findAtomAndOffset(srcAddr).atom )
									dstAddr = BigEndian::get64(*((uint64_t*)fixUpPtr)) + nextRelocValue;
								else
									nextRelocValue = dstAddr - BigEndian::get64(*((uint64_t*)fixUpPtr));
							}
							break;
					}
					makeReference(pointerDiffKindForLength_powerpc(sreloc->r_length()), srcAddr, nextRelocValue, dstAddr);
				}
				break;
			case PPC_RELOC_PAIR:
				break;
			case PPC_RELOC_HI16_SECTDIFF:
				printf("unexpected scattered relocation type PPC_RELOC_HI16_SECTDIFF\n");
				break;
			default:
				printf("unknown scattered relocation type %d\n", sreloc->r_type());
		}
	}
	return result;
}

template <>
ppc::ReferenceKinds Reader<ppc>::pointerDiffKindForLength_powerpc(uint8_t r_length)
{
	if ( r_length == 2 )
		return ppc::kPointerDiff32;
	else if ( r_length == 1 )
		return ppc::kPointerDiff16;
	else
		throw "bad diff relocations r_length for ppc architecture";
 }

template <>
ppc64::ReferenceKinds Reader<ppc64>::pointerDiffKindForLength_powerpc(uint8_t r_length)
{
	if ( r_length == 2 )
		return ppc64::kPointerDiff32;
	else if ( r_length == 3 )
		return ppc64::kPointerDiff64;
	else
		throw "bad diff relocations r_length for ppc64 architecture";
 }

template <>
bool Reader<x86>::addRelocReference(const macho_section<x86::P>* sect, const macho_relocation_info<x86::P>* reloc)
{
	uint32_t srcAddr;
	uint32_t dstAddr;
	uint32_t* fixUpPtr;
	bool result = false;
	if ( (reloc->r_address() & R_SCATTERED) == 0 ) {
		srcAddr = sect->addr() + reloc->r_address();
		fixUpPtr = (uint32_t*)((char*)(fHeader) + sect->offset() + reloc->r_address());
		switch ( reloc->r_type() ) {
			case GENERIC_RELOC_VANILLA:
				{
					x86::ReferenceKinds kind = x86::kPointer;
					uint32_t pointerValue = E::get32(*fixUpPtr);
					if ( reloc->r_pcrel() ) {
						switch( reloc->r_length() ) {
							case 0:
							case 3:
								throw "bad pc-rel vanilla relocation length";
							case 1:
								kind = x86::kPCRel16;
								pointerValue = srcAddr + (int16_t)E::get16(*((uint16_t*)fixUpPtr)) + sizeof(uint16_t);
								break;
							case 2:
								kind = x86::kPCRel32;
								pointerValue += srcAddr + sizeof(uint32_t);
								break;
						}
					}
					else if ( strcmp(sect->segname(), "__TEXT") == 0 ) {
						kind = x86::kAbsolute32;
						if ( reloc->r_length() != 2 )
							throw "bad vanilla relocation length";
					}
					else {
						kind = x86::kPointer;
						if ( reloc->r_length() != 2 )
							throw "bad vanilla relocation length";
					}
					if ( reloc->r_extern() ) {
						const macho_nlist<P>* targetSymbol = &fSymbols[reloc->r_symbolnum()];
						if ( this->isWeakImportSymbol(targetSymbol) )
							kind = x86::kPointerWeakImport;
						const char* targetName = &fStrings[targetSymbol->n_strx()];
						if ( strncmp(targetName, "___dtrace_probe$", 16) == 0 ) {
							makeByNameReference(x86::kDtraceProbeSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[16]);
						}
						else if ( strncmp(targetName, "___dtrace_isenabled$", 20) == 0 ) {
							makeByNameReference(x86::kDtraceIsEnabledSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[20]);
						}
						else
							makeByNameReference(kind, srcAddr, targetName, pointerValue);
					}
					else {
						// if this is a branch to a stub, we need to see if the stub is for a weak imported symbol
						ObjectFile::Atom* atom = findAtomAndOffset(pointerValue).atom;
						const char* targetName = atom->getName();
						if ( (targetName != NULL) && (strncmp(targetName, "___dtrace_probe$", 16) == 0) ) {
							makeByNameReference(x86::kDtraceProbeSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[16]);
						}
						else if ( (targetName != NULL) && (strncmp(targetName, "___dtrace_isenabled$", 20) == 0) ) {
							makeByNameReference(x86::kDtraceIsEnabledSite, srcAddr, targetName, 0);
							addDtraceExtraInfos(srcAddr, &targetName[20]);
						}
						else if ( reloc->r_pcrel() && (atom->getSymbolTableInclusion() == ObjectFile::Atom::kSymbolTableNotIn)
							&& ((AnonymousAtom<x86>*)atom)->isWeakImportStub() )
							makeReference(x86::kPCRel32WeakImport, srcAddr, pointerValue);
						else if ( reloc->r_symbolnum() != R_ABS )
							makeReference(kind, srcAddr, pointerValue);
						else {
							// find absolute symbol that corresponds to pointerValue
							std::map<uint32_t, BaseAtom*>::iterator pos = fAddrToAbsoluteAtom.find(pointerValue);
							if ( pos != fAddrToAbsoluteAtom.end() ) 
								makeByNameReference(kind, srcAddr, pos->second->getName(), 0);
							else
								throwf("R_ABS reloc but no absolute symbol at target address");
						}
					}
				}
				break;
			default:
				printf("unknown relocation type %d\n", reloc->r_type());
		}
	}
	else {
		const macho_scattered_relocation_info<P>* sreloc = (macho_scattered_relocation_info<P>*)reloc;
		srcAddr = sect->addr() + sreloc->r_address();
		dstAddr = sreloc->r_value();
		fixUpPtr = (uint32_t*)((char*)(fHeader) + sect->offset() + sreloc->r_address());
		const macho_scattered_relocation_info<P>* nextSReloc = &sreloc[1];
		const macho_relocation_info<P>* nextReloc = &reloc[1];
		pint_t betterDstAddr;
		// file format allows pair to be scattered or not
		bool nextRelocIsPair = false;
		uint32_t nextRelocAddress = 0;
		uint32_t nextRelocValue = 0;
		if ( (nextReloc->r_address() & R_SCATTERED) == 0 ) {
			if ( nextReloc->r_type() == PPC_RELOC_PAIR ) {
				nextRelocIsPair = true;
				nextRelocAddress = nextReloc->r_address();
				result = true;
			}
		}
		else {
			if ( nextSReloc->r_type() == PPC_RELOC_PAIR ) {
				nextRelocIsPair = true;
				nextRelocAddress = nextSReloc->r_address();
				nextRelocValue = nextSReloc->r_value();
			}
		}
		switch (sreloc->r_type()) {
			case GENERIC_RELOC_VANILLA:
					betterDstAddr = LittleEndian::get32(*fixUpPtr);
					//fprintf(stderr, "pointer reloc: srcAddr=0x%08X, dstAddr=0x%08X, pointer=0x%08lX\n", srcAddr, dstAddr, betterDstAddr);
					// with a scattered relocation we get both the target (sreloc->r_value()) and the target+offset (*fixUpPtr)
					if ( sreloc->r_pcrel() ) {
						betterDstAddr += srcAddr + 4;
						makeReferenceWithToBase(x86::kPCRel32, srcAddr, betterDstAddr, dstAddr);
					}
					else {
						if ( strcmp(sect->segname(), "__TEXT") == 0 )
							makeReferenceWithToBase(x86::kAbsolute32, srcAddr, betterDstAddr, dstAddr);
						else
							makeReferenceWithToBase(x86::kPointer, srcAddr, betterDstAddr, dstAddr);
					}
				break;
			case GENERIC_RELOC_SECTDIFF:
			case GENERIC_RELOC_LOCAL_SECTDIFF:
				{
					if ( !nextRelocIsPair ) {
						printf("GENERIC_RELOC_SECTDIFF missing following pair\n");
						break;
					}
					x86::ReferenceKinds kind = x86::kPointerDiff;
					uint32_t contentAddr = 0;
					switch ( sreloc->r_length() ) {
						case 0:
						case 3:
							throw "bad length for GENERIC_RELOC_SECTDIFF";
						case 1:
							kind = x86::kPointerDiff16;
							contentAddr = LittleEndian::get16(*((uint16_t*)fixUpPtr));
							break;
						case 2:
							kind = x86::kPointerDiff;
							contentAddr = LittleEndian::get32(*fixUpPtr);
							break;
					}
					AtomAndOffset srcao  = findAtomAndOffset(srcAddr);
					AtomAndOffset fromao = findAtomAndOffset(nextRelocValue);
					AtomAndOffset toao   = findAtomAndOffset(dstAddr);
					// check for addend encoded in the section content
					//fprintf(stderr, "addRef: dstAddr=0x%X, nextRelocValue=0x%X, contentAddr=0x%X\n",
					//		dstAddr, nextRelocValue, contentAddr);
					if ( (dstAddr - nextRelocValue) != contentAddr ) {
						if ( toao.atom == srcao.atom )
							toao.offset += (contentAddr + nextRelocValue) - dstAddr;
						else if ( fromao.atom == srcao.atom )
							toao.offset += (contentAddr + nextRelocValue) - dstAddr;
						else
							fromao.offset += (dstAddr - contentAddr) - nextRelocValue;
					}
					//fprintf(stderr, "addRef: src=%s+0x%X, from=%s+0x%X, to=%s+0x%X\n",
					//	srcao.atom->getDisplayName(), srcao.offset, 
					//	fromao.atom->getDisplayName(), fromao.offset, 
					//	toao.atom->getDisplayName(), toao.offset);
					new Reference<x86>(kind, srcao, fromao, toao);
				}
				break;
			case GENERIC_RELOC_PAIR:
				// do nothing, already used via a look ahead
				break;
			default:
				printf("unknown scattered relocation type %d\n", sreloc->r_type());
		}
	}
	return result;
}

template <>
bool Reader<x86_64>::addRelocReference(const macho_section<x86_64::P>* sect, const macho_relocation_info<x86_64::P>* reloc)
{
	uint64_t srcAddr;
	uint64_t dstAddr = 0;
	uint64_t addend;
	uint32_t* fixUpPtr;
	x86_64::ReferenceKinds kind = x86_64::kNoFixUp;
	bool result = false;
	const macho_nlist<P>* targetSymbol = NULL;
	const char* targetName = NULL;
	srcAddr = sect->addr() + reloc->r_address();
	fixUpPtr = (uint32_t*)((char*)(fHeader) + sect->offset() + reloc->r_address());
	//fprintf(stderr, "addReloc type=%d\n", reloc->r_type());
	if ( reloc->r_extern() ) {
		targetSymbol = &fSymbols[reloc->r_symbolnum()];
		targetName = &fStrings[targetSymbol->n_strx()];
	}
	switch ( reloc->r_type() ) {
		case X86_64_RELOC_UNSIGNED:
			if ( reloc->r_pcrel() )
				throw "pcrel and X86_64_RELOC_UNSIGNED not supported";
			if ( reloc->r_length() != 3 ) 
				throw "length < 3 and X86_64_RELOC_UNSIGNED not supported";
			dstAddr = E::get64(*((uint64_t*)fixUpPtr));
			if ( reloc->r_extern() ) {
				makeReferenceToSymbol(x86_64::kPointer, srcAddr, targetSymbol, dstAddr);
			}
			else {
				makeReference(x86_64::kPointer, srcAddr, dstAddr);
				// verify that dstAddr is in the section being targeted
				int sectNum = reloc->r_symbolnum();
				const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)fSegment + sizeof(macho_segment_command<P>));
				const macho_section<P>* const targetSection = &sectionsStart[sectNum-1];
				if ( (dstAddr < targetSection->addr()) || (dstAddr > (targetSection->addr()+targetSection->size())) ) {
					throwf("local relocation for address 0x%08llX in section %s does not target section %s", 
							srcAddr, sect->sectname(), targetSection->sectname());
				}
			}
			break;
		case X86_64_RELOC_SIGNED:
		case X86_64_RELOC_SIGNED_1:
		case X86_64_RELOC_SIGNED_2:
		case X86_64_RELOC_SIGNED_4:
			if ( ! reloc->r_pcrel() )
				throw "not pcrel and X86_64_RELOC_SIGNED* not supported";
			if ( reloc->r_length() != 2 ) 
				throw "length != 2 and X86_64_RELOC_SIGNED* not supported";
			addend = (int64_t)((int32_t)(E::get32(*fixUpPtr)));
			if ( reloc->r_extern() ) {
				switch ( reloc->r_type() ) {
					case X86_64_RELOC_SIGNED:
						kind = x86_64::kPCRel32;
						// begin support for old .o files before X86_64_RELOC_SIGNED_1 was created
						if ( addend == (uint64_t)(-1) ) {
							addend = 0;
							kind = x86_64::kPCRel32_1;
						}
						else if ( addend == (uint64_t)(-2) ) {
							addend = 0;
							kind = x86_64::kPCRel32_2;
						}
						else if ( addend == (uint64_t)(-4) ) {
							addend = 0;
							kind = x86_64::kPCRel32_4;
						}
						break;
						// end support for old .o files before X86_64_RELOC_SIGNED_1 was created
					case X86_64_RELOC_SIGNED_1:
						kind = x86_64::kPCRel32_1;
						addend += 1;
						break;	
					case X86_64_RELOC_SIGNED_2:
						kind = x86_64::kPCRel32_2;
						addend += 2;
						break;	
					case X86_64_RELOC_SIGNED_4:
						kind = x86_64::kPCRel32_4;
						addend += 4;
						break;
				}
				makeReferenceToSymbol(kind, srcAddr, targetSymbol, addend);
			}
			else {
				uint64_t ripRelativeOffset = addend;
				switch ( reloc->r_type() ) {
					case X86_64_RELOC_SIGNED:
						dstAddr = srcAddr + 4 + ripRelativeOffset;
						kind = x86_64::kPCRel32;
						break;
					case X86_64_RELOC_SIGNED_1:
						dstAddr = srcAddr + 5 + ripRelativeOffset;
						kind = x86_64::kPCRel32_1;
						break;	
					case X86_64_RELOC_SIGNED_2:
						dstAddr = srcAddr + 6 + ripRelativeOffset;
						kind = x86_64::kPCRel32_2;
						break;	
					case X86_64_RELOC_SIGNED_4:
						dstAddr = srcAddr + 8 + ripRelativeOffset;
						kind = x86_64::kPCRel32_4;
						break;
				}
				makeReference(kind, srcAddr, dstAddr);
				// verify that dstAddr is in the section being targeted
				int sectNum = reloc->r_symbolnum();
				const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)fSegment + sizeof(macho_segment_command<P>));
				const macho_section<P>* const targetSection = &sectionsStart[sectNum-1];
				if ( (dstAddr < targetSection->addr()) || (dstAddr > (targetSection->addr()+targetSection->size())) ) {
					throwf("local relocation for address 0x%08llX in section %s does not target section %s", 
							srcAddr, sect->sectname(), targetSection->sectname());
				}
			}	
			break;
		case X86_64_RELOC_BRANCH:
			if ( ! reloc->r_pcrel() )
				throw "not pcrel and X86_64_RELOC_BRANCH not supported";
			if ( reloc->r_length() != 2 ) 
				throw "length != 2 and X86_64_RELOC_BRANCH not supported";
			dstAddr = (int64_t)((int32_t)(E::get32(*fixUpPtr)));
			if ( reloc->r_extern() ) {
				if ( strncmp(targetName, "___dtrace_probe$", 16) == 0 ) {
					makeByNameReference(x86_64::kDtraceProbeSite, srcAddr, targetName, 0);
					addDtraceExtraInfos(srcAddr, &targetName[16]);
				}
				else if ( strncmp(targetName, "___dtrace_isenabled$", 20) == 0 ) {
					makeByNameReference(x86_64::kDtraceIsEnabledSite, srcAddr, targetName, 0);
					addDtraceExtraInfos(srcAddr, &targetName[16]);
				}
				else if ( isWeakImportSymbol(targetSymbol) )
					makeReferenceToSymbol(x86_64::kBranchPCRel32WeakImport, srcAddr, targetSymbol, dstAddr);
				else
					makeReferenceToSymbol(x86_64::kBranchPCRel32, srcAddr, targetSymbol, dstAddr);
			}
			else {
				makeReference(x86_64::kBranchPCRel32, srcAddr, srcAddr+4+dstAddr);
			}
			break;
		case X86_64_RELOC_GOT:
			if ( ! reloc->r_extern() ) 
				throw "not extern and X86_64_RELOC_GOT not supported";
			if ( ! reloc->r_pcrel() )
				throw "not pcrel and X86_64_RELOC_GOT not supported";
			if ( reloc->r_length() != 2 ) 
				throw "length != 2 and X86_64_RELOC_GOT not supported";
			addend = (int64_t)((int32_t)(E::get32(*fixUpPtr)));
			if ( isWeakImportSymbol(targetSymbol) )
				makeReferenceToSymbol(x86_64::kPCRel32GOTWeakImport, srcAddr, targetSymbol, addend);
			else
				makeReferenceToSymbol(x86_64::kPCRel32GOT, srcAddr, targetSymbol, addend);
			break;
		case X86_64_RELOC_GOT_LOAD:
			if ( ! reloc->r_extern() ) 
				throw "not extern and X86_64_RELOC_GOT_LOAD not supported";
			if ( ! reloc->r_pcrel() )
				throw "not pcrel and X86_64_RELOC_GOT_LOAD not supported";
			if ( reloc->r_length() != 2 ) 
				throw "length != 2 and X86_64_RELOC_GOT_LOAD not supported";
			addend = (int64_t)((int32_t)(E::get32(*fixUpPtr)));
			if ( isWeakImportSymbol(targetSymbol) )
				makeReferenceToSymbol(x86_64::kPCRel32GOTLoadWeakImport, srcAddr, targetSymbol, addend);
			else
				makeReferenceToSymbol(x86_64::kPCRel32GOTLoad, srcAddr, targetSymbol, addend);
			break;
		case X86_64_RELOC_SUBTRACTOR:
		{
			if ( reloc->r_pcrel() )
				throw "X86_64_RELOC_SUBTRACTOR cannot be pc-relative";
			if ( reloc->r_length() < 2 )
				throw "X86_64_RELOC_SUBTRACTOR must have r_length of 2 or 3";
			if ( !reloc->r_extern() )
				throw "X86_64_RELOC_SUBTRACTOR must have r_extern=1";
			const macho_relocation_info<x86_64::P>* nextReloc = &reloc[1];
			if ( nextReloc->r_type() != X86_64_RELOC_UNSIGNED )
				throw "X86_64_RELOC_SUBTRACTOR must be followed by X86_64_RELOC_UNSIGNED";
			result = true;
			if ( nextReloc->r_pcrel() )
				throw "X86_64_RELOC_UNSIGNED following a X86_64_RELOC_SUBTRACTOR cannot be pc-relative";
			if ( nextReloc->r_length() != reloc->r_length() )
				throw "X86_64_RELOC_UNSIGNED following a X86_64_RELOC_SUBTRACTOR must have same r_length";
			Reference<x86_64>* ref;
			bool negativeAddend;
			if ( reloc->r_length() == 2 ) {
				kind = x86_64::kPointerDiff32;
				dstAddr = E::get32(*fixUpPtr); // addend is in content
				negativeAddend = ((dstAddr & 0x80000000) != 0);
			}
			else {
				kind = x86_64::kPointerDiff;
				dstAddr = E::get64(*((uint64_t*)fixUpPtr)); // addend is in content
				negativeAddend = ((dstAddr & 0x8000000000000000ULL) != 0);
			}
			ObjectFile::Atom* inAtom = this->findAtomAndOffset(srcAddr).atom;
			// create reference with "to" target
			if ( nextReloc->r_extern() ) {
				const macho_nlist<P>* targetSymbol = &fSymbols[nextReloc->r_symbolnum()];
				const char* targetName = &fStrings[targetSymbol->n_strx()];
				ref = makeReferenceToSymbol(kind, srcAddr, targetSymbol, 0);
				// if "to" is in this atom, change by-name to a direct reference
				if ( strcmp(targetName, inAtom->getName()) == 0 )
					ref->setTarget(*inAtom, 0);
			}
			else {
				ref = makeReference(kind, srcAddr, dstAddr);
			}
			// add in "from" target
			if ( reloc->r_extern() ) {
				const macho_nlist<P>* targetFromSymbol = &fSymbols[reloc->r_symbolnum()];
				const char* fromTargetName = &fStrings[targetFromSymbol->n_strx()];
				if ( (targetFromSymbol->n_type() & N_EXT) == 0 ) {
					// from target is translation unit scoped, so use a direct reference
					ref->setFromTarget(*(findAtomAndOffset(targetSymbol->n_value()).atom));
				}
				else if ( strcmp(fromTargetName, inAtom->getName()) == 0 ) {
					// if "from" is in this atom, change by-name to a direct reference
					ref->setFromTarget(*inAtom);
				}
				else {
					// some non-static other atom
					ref->setFromTargetName(fromTargetName);
				}
			}
			// addend goes in from side iff negative
			if ( negativeAddend )
				ref->setFromTargetOffset(-dstAddr);
			else
				ref->setToTargetOffset(dstAddr);
			break;
		}
		default:
			fprintf(stderr, "unknown relocation type %d\n", reloc->r_type());
	}
	return result;
}


template <typename A>
void Reader<A>::addReferencesForSection(const macho_section<P>* sect)
{
	// ignore dwarf sections.  If ld ever supports processing dwarf, this logic will need to change
	if ( (sect->flags() & S_ATTR_DEBUG) == 0 ) {
		switch ( sect->flags() & SECTION_TYPE ) {
			case S_SYMBOL_STUBS:
			case S_LAZY_SYMBOL_POINTERS:
				// we ignore compiler generated stubs, so ignore those relocs too
				break;
			default:
				const macho_relocation_info<P>* relocs = (macho_relocation_info<P>*)((char*)(fHeader) + sect->reloff());
				const uint32_t relocCount = sect->nreloc();
				//fprintf(stderr, "relocCount = %d in section %s\n", relocCount, sect->sectname());
				for (uint32_t r = 0; r < relocCount; ++r) {
					try {
						if ( addRelocReference(sect, &relocs[r]) )
							++r; // skip next
					}
					catch (const char* msg) {
						throwf("in section %s,%s reloc %u: %s\n", sect->segname(), sect->sectname(), r, msg);
					}
				}
		}
	}
}


template <>
const char* Reference<x86>::getDescription() const
{
	static char temp[2048];
	switch( fKind ) {
		case x86::kNoFixUp:
			sprintf(temp, "reference to ");
			break;
		case x86::kFollowOn:
			sprintf(temp, "followed by ");
			break;
		case x86::kPointerWeakImport:
			sprintf(temp, "offset 0x%04X, weak import pointer to ", fFixUpOffsetInSrc);
			break;
		case x86::kPointer:
			sprintf(temp, "offset 0x%04X, pointer to ", fFixUpOffsetInSrc);
			break;
		case x86::kPointerDiff:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04X, 32-bit pointer difference: (&%s%s%s + 0x%08X) - (&%s%s%s + 0x%08X)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
			break;
		case x86::kPointerDiff16:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04X, 16-bit pointer difference: (&%s%s%s + 0x%08X) - (&%s%s%s + 0x%08X)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
			break;
		case x86::kPCRel32WeakImport:
			sprintf(temp, "offset 0x%04X, rel32 reference to weak imported ", fFixUpOffsetInSrc);
			break;
		case x86::kPCRel32:
			sprintf(temp, "offset 0x%04X, rel32 reference to ", fFixUpOffsetInSrc);
			break;
		case x86::kPCRel16:
			sprintf(temp, "offset 0x%04X, rel16 reference to ", fFixUpOffsetInSrc);
			break;
		case x86::kAbsolute32:
			sprintf(temp, "offset 0x%04X, absolute32 reference to ", fFixUpOffsetInSrc);
			break;
		case x86::kDtraceProbe:
			sprintf(temp, "offset 0x%04X, dtrace static probe ", fFixUpOffsetInSrc);
			break;
		case x86::kDtraceProbeSite:
			sprintf(temp, "offset 0x%04X, dtrace static probe site", fFixUpOffsetInSrc);
			break;
		case x86::kDtraceIsEnabledSite:
			sprintf(temp, "offset 0x%04X, dtrace static probe is-enabled site", fFixUpOffsetInSrc);
			break;
		case x86::kDtraceTypeReference:
			sprintf(temp, "offset 0x%04X, dtrace type/stability reference", fFixUpOffsetInSrc);
			break;
	}
	// always quote by-name references
	if ( fToTargetName != NULL ) {
		strcat(temp, "\"");
		strcat(temp, fToTargetName);
		strcat(temp, "\"");
	}
	else if ( fToTarget.atom != NULL ) {
		strcat(temp, fToTarget.atom->getDisplayName());
	}
	else {
		strcat(temp, "NULL target");
	}
	if ( fToTarget.offset != 0 )
		sprintf(&temp[strlen(temp)], " plus 0x%08X", fToTarget.offset);

	return temp;
}


template <>
const char* Reference<ppc>::getDescription() const
{
	static char temp[2048];
	switch( fKind ) {
		case ppc::kNoFixUp:
			sprintf(temp, "reference to ");
			break;
		case ppc::kFollowOn:
			sprintf(temp, "followed by ");
			break;
		case ppc::kPointerWeakImport:
			sprintf(temp, "offset 0x%04X, weak import pointer to ", fFixUpOffsetInSrc);
			break;
		case ppc::kPointer:
			sprintf(temp, "offset 0x%04X, pointer to ", fFixUpOffsetInSrc);
			break;
		case ppc::kPointerDiff16:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04X, 16-bit pointer difference: (&%s%s%s + %d) - (&%s%s%s + %d)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
		case ppc::kPointerDiff32:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04X, 32-bit pointer difference: (&%s%s%s + %d) - (&%s%s%s + %d)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
		case ppc::kPointerDiff64:
			throw "unsupported refrence kind";
			break;
		case ppc::kBranch24WeakImport:
			sprintf(temp, "offset 0x%04X, pc-rel branch fixup to weak imported ", fFixUpOffsetInSrc);
			break;
		case ppc::kBranch24:
		case ppc::kBranch14:
			sprintf(temp, "offset 0x%04X, pc-rel branch fixup to ", fFixUpOffsetInSrc);
			break;
		case ppc::kPICBaseLow16:
			sprintf(temp, "offset 0x%04X, low  16 fixup from pic-base of %s plus 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.atom->getDisplayName(), fFromTarget.offset);
			break;
		case ppc::kPICBaseLow14:
			sprintf(temp, "offset 0x%04X, low  14 fixup from pic-base of %s plus 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.atom->getDisplayName(), fFromTarget.offset);
			break;
		case ppc::kPICBaseHigh16:
			sprintf(temp, "offset 0x%04X, high 16 fixup from pic-base of %s plus 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.atom->getDisplayName(), fFromTarget.offset);
			break;
		case ppc::kAbsLow16:
			sprintf(temp, "offset 0x%04X, low  16 fixup to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc::kAbsLow14:
			sprintf(temp, "offset 0x%04X, low  14 fixup to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc::kAbsHigh16:
			sprintf(temp, "offset 0x%04X, high 16 fixup or to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc::kAbsHigh16AddLow:
			sprintf(temp, "offset 0x%04X, high 16 fixup add to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc::kDtraceProbe:
			sprintf(temp, "offset 0x%04X, dtrace static probe ", fFixUpOffsetInSrc);
			break;
		case ppc::kDtraceProbeSite:
			sprintf(temp, "offset 0x%04X, dtrace static probe site", fFixUpOffsetInSrc);
			break;
		case ppc::kDtraceIsEnabledSite:
			sprintf(temp, "offset 0x%04X, dtrace static probe is-enabled site", fFixUpOffsetInSrc);
			break;
		case ppc::kDtraceTypeReference:
			sprintf(temp, "offset 0x%04X, dtrace type/stability reference", fFixUpOffsetInSrc);
			break;
	}
	// always quote by-name references
	if ( fToTargetName != NULL ) {
		strcat(temp, "\"");
		strcat(temp, fToTargetName);
		strcat(temp, "\"");
	}
	else if ( fToTarget.atom != NULL ) {
		strcat(temp, fToTarget.atom->getDisplayName());
	}
	else {
		strcat(temp, "NULL target");
	}
	if ( fToTarget.offset != 0 )
		sprintf(&temp[strlen(temp)], " plus 0x%08X", fToTarget.offset);

	return temp;
}

template <>
const char* Reference<ppc64>::getDescription() const
{
	static char temp[2048];
	switch( fKind ) {
		case ppc64::kNoFixUp:
			sprintf(temp, "reference to ");
			break;
		case ppc64::kFollowOn:
			sprintf(temp, "followed by ");
			break;
		case ppc64::kPointerWeakImport:
			sprintf(temp, "offset 0x%04llX, weak import pointer to ", fFixUpOffsetInSrc);
			break;
		case ppc64::kPointer:
			sprintf(temp, "offset 0x%04llX, pointer to ", fFixUpOffsetInSrc);
			break;
		case ppc64::kPointerDiff64:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04llX, 64-bit pointer difference: (&%s%s%s + %u) - (&%s%s%s + %u)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
		case ppc64::kPointerDiff32:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04llX, 32-bit pointer difference: (&%s%s%s + %u) - (&%s%s%s + %u)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
		case ppc64::kPointerDiff16:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			sprintf(temp, "offset 0x%04llX, 16-bit pointer difference: (&%s%s%s + %u) - (&%s%s%s + %u)",
				fFixUpOffsetInSrc, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
		case ppc64::kBranch24WeakImport:
			sprintf(temp, "offset 0x%04llX, pc-rel branch fixup to weak imported ", fFixUpOffsetInSrc);
			break;
		case ppc64::kBranch24:
		case ppc64::kBranch14:
			sprintf(temp, "offset 0x%04llX, pc-rel branch fixup to ", fFixUpOffsetInSrc);
			break;
		case ppc64::kPICBaseLow16:
			sprintf(temp, "offset 0x%04llX, low  16 fixup from pic-base offset 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.offset);
			break;
		case ppc64::kPICBaseLow14:
			sprintf(temp, "offset 0x%04llX, low  14 fixup from pic-base offset 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.offset);
			break;
		case ppc64::kPICBaseHigh16:
			sprintf(temp, "offset 0x%04llX, high 16 fixup from pic-base offset 0x%04X to ", fFixUpOffsetInSrc, fFromTarget.offset);
			break;
		case ppc64::kAbsLow16:
			sprintf(temp, "offset 0x%04llX, low  16 fixup to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc64::kAbsLow14:
			sprintf(temp, "offset 0x%04llX, low  14 fixup to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc64::kAbsHigh16:
			sprintf(temp, "offset 0x%04llX, high 16 fixup or to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc64::kAbsHigh16AddLow:
			sprintf(temp, "offset 0x%04llX, high 16 fixup add to absolute address of ", fFixUpOffsetInSrc);
			break;
		case ppc64::kDtraceProbe:
			sprintf(temp, "offset 0x%04llX, dtrace static probe ", fFixUpOffsetInSrc);
			break;
		case ppc64::kDtraceProbeSite:
			sprintf(temp, "offset 0x%04llX, dtrace static probe site", fFixUpOffsetInSrc);
			break;
		case ppc64::kDtraceIsEnabledSite:
			sprintf(temp, "offset 0x%04llX, dtrace static probe is-enabled site", fFixUpOffsetInSrc);
			break;
		case ppc64::kDtraceTypeReference:
			sprintf(temp, "offset 0x%04llX, dtrace type/stability reference", fFixUpOffsetInSrc);
			break;
	}
	// always quote by-name references
	if ( fToTargetName != NULL ) {
		strcat(temp, "\"");
		strcat(temp, fToTargetName);
		strcat(temp, "\"");
	}
	else if ( fToTarget.atom != NULL ) {
		strcat(temp, fToTarget.atom->getDisplayName());
	}
	else {
		strcat(temp, "NULL target");
	}
	if ( fToTarget.offset != 0 )
		sprintf(&temp[strlen(temp)], " plus 0x%llX", this->getTargetOffset());

	return temp;
}


template <>
const char* Reference<x86_64>::getDescription() const
{
	static char temp[2048];
	switch( fKind ) {
		case x86_64::kNoFixUp:
			sprintf(temp, "reference to ");
			break;
		case x86_64::kFollowOn:
			sprintf(temp, "followed by ");
			break;
		case x86_64::kPointerWeakImport:
			sprintf(temp, "offset 0x%04llX, weak import pointer to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPointer:
			sprintf(temp, "offset 0x%04llX, pointer to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPointerDiff32:
		case x86_64::kPointerDiff:
			{
			// by-name references have quoted names
			const char* targetQuotes = (&(this->getTarget()) == NULL) ? "\"" : "";
			const char* fromQuotes = (&(this->getFromTarget()) == NULL) ? "\"" : "";
			const char* size = (fKind == x86_64::kPointerDiff32) ? "32-bit" : "64-bit";
			sprintf(temp, "offset 0x%04llX, %s pointer difference: (&%s%s%s + 0x%08X) - (&%s%s%s + 0x%08X)",
				fFixUpOffsetInSrc, size, targetQuotes, this->getTargetName(), targetQuotes, fToTarget.offset,
							   fromQuotes, this->getFromTargetName(), fromQuotes, fFromTarget.offset );
			return temp;
			}
			break;
		case x86_64::kPCRel32:
			sprintf(temp, "offset 0x%04llX, rel32 reference to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32_1:
			sprintf(temp, "offset 0x%04llX, rel32-1 reference to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32_2:
			sprintf(temp, "offset 0x%04llX, rel32-2 reference to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32_4:
			sprintf(temp, "offset 0x%04llX, rel32-4 reference to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kBranchPCRel32:
			sprintf(temp, "offset 0x%04llX, branch rel32 reference to ", fFixUpOffsetInSrc);
			break;
		case x86_64::kBranchPCRel32WeakImport:
			sprintf(temp, "offset 0x%04llX, branch rel32 reference to weak imported ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32GOT:
			sprintf(temp, "offset 0x%04llX, rel32 reference to GOT entry for ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32GOTWeakImport:
			sprintf(temp, "offset 0x%04llX, rel32 reference to GOT entry for weak imported ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32GOTLoad:
			sprintf(temp, "offset 0x%04llX, rel32 reference to GOT entry for ", fFixUpOffsetInSrc);
			break;
		case x86_64::kPCRel32GOTLoadWeakImport:
			sprintf(temp, "offset 0x%04llX, rel32 reference to GOT entry for weak imported ", fFixUpOffsetInSrc);
			break;
		case x86_64::kDtraceProbe:
			sprintf(temp, "offset 0x%04llX, dtrace static probe ", fFixUpOffsetInSrc);
			break;
		case x86_64::kDtraceProbeSite:
			sprintf(temp, "offset 0x%04llX, dtrace static probe site", fFixUpOffsetInSrc);
			break;
		case x86_64::kDtraceIsEnabledSite:
			sprintf(temp, "offset 0x%04llX, dtrace static probe is-enabled site", fFixUpOffsetInSrc);
			break;
		case x86_64::kDtraceTypeReference:
			sprintf(temp, "offset 0x%04llX, dtrace type/stability reference", fFixUpOffsetInSrc);
			break;
	}
	// always quote by-name references
	if ( fToTargetName != NULL ) {
		strcat(temp, "\"");
		strcat(temp, fToTargetName);
		strcat(temp, "\"");
	}
	else if ( fToTarget.atom != NULL ) {
		strcat(temp, fToTarget.atom->getDisplayName());
	}
	else {
		strcat(temp, "NULL target");
	}
	if ( fToTarget.offset != 0 )
		sprintf(&temp[strlen(temp)], " plus 0x%llX", this->getTargetOffset());

	return temp;
}



}; // namespace relocatable
}; // namespace mach_o

#endif // __OBJECT_FILE_MACH_O__