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src/ImageLoader.cpp dyld-433.5 dyld-97.1
--- dyld/dyld-433.5/src/ImageLoader.cpp
+++ dyld/dyld-97.1/src/ImageLoader.cpp
@@ -1,6 +1,6 @@
 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
  *
- * Copyright (c) 2004-2010 Apple Inc. All rights reserved.
+ * Copyright (c) 2004-2006 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
@@ -24,7 +24,6 @@
 
 #define __STDC_LIMIT_MACROS
 #include <stdint.h>
-#include <stdlib.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <mach/mach.h>
@@ -38,11 +37,13 @@
 
 #include "ImageLoader.h"
 
+// in libc.a
+extern "C" void _spin_lock(uint32_t*);
+extern "C" void _spin_unlock(uint32_t*);
 
 uint32_t								ImageLoader::fgImagesUsedFromSharedCache = 0;
 uint32_t								ImageLoader::fgImagesWithUsedPrebinding = 0;
-uint32_t								ImageLoader::fgImagesRequiringCoalescing = 0;
-uint32_t								ImageLoader::fgImagesHasWeakDefinitions = 0;
+uint32_t								ImageLoader::fgImagesRequiringNoFixups = 0;
 uint32_t								ImageLoader::fgTotalRebaseFixups = 0;
 uint32_t								ImageLoader::fgTotalBindFixups = 0;
 uint32_t								ImageLoader::fgTotalBindSymbolsResolved = 0;
@@ -53,64 +54,102 @@
 uint64_t								ImageLoader::fgTotalBytesMapped = 0;
 uint64_t								ImageLoader::fgTotalBytesPreFetched = 0;
 uint64_t								ImageLoader::fgTotalLoadLibrariesTime;
-uint64_t								ImageLoader::fgTotalObjCSetupTime = 0;
-uint64_t								ImageLoader::fgTotalDebuggerPausedTime = 0;
-uint64_t								ImageLoader::fgTotalRebindCacheTime = 0;
 uint64_t								ImageLoader::fgTotalRebaseTime;
 uint64_t								ImageLoader::fgTotalBindTime;
-uint64_t								ImageLoader::fgTotalWeakBindTime;
-uint64_t								ImageLoader::fgTotalDOF;
 uint64_t								ImageLoader::fgTotalInitTime;
+uintptr_t								ImageLoader::fgNextSplitSegAddress = 0x90000000;
 uint16_t								ImageLoader::fgLoadOrdinal = 0;
-uint32_t								ImageLoader::fgSymbolTrieSearchs = 0;
-std::vector<ImageLoader::InterposeTuple>ImageLoader::fgInterposingTuples;
-uintptr_t								ImageLoader::fgNextPIEDylibAddress = 0;
-
-
-
-ImageLoader::ImageLoader(const char* path, unsigned int libCount)
-	: fPath(path), fRealPath(NULL), fDevice(0), fInode(0), fLastModified(0), 
-	fPathHash(0), fDlopenReferenceCount(0), fInitializerRecursiveLock(NULL), 
-	fDepth(0), fLoadOrder(fgLoadOrdinal++), fState(0), fLibraryCount(libCount), 
-	fAllLibraryChecksumsAndLoadAddressesMatch(false), fLeaveMapped(false), fNeverUnload(false),
-	fHideSymbols(false), fMatchByInstallName(false),
-	fInterposed(false), fRegisteredDOF(false), fAllLazyPointersBound(false), 
-    fBeingRemoved(false), fAddFuncNotified(false),
-	fPathOwnedByImage(false), fIsReferencedDownward(false), 
-	fWeakSymbolsBound(false)
-{
-	if ( fPath != NULL )
-		fPathHash = hash(fPath);
-	if ( libCount > 512 )
-		dyld::throwf("too many dependent dylibs in %s", path);
-}
-
-
-void ImageLoader::deleteImage(ImageLoader* image)
-{
-	delete image;
-}
-
-
-ImageLoader::~ImageLoader()
-{
-	if ( fRealPath != NULL ) 
-		delete [] fRealPath;
-	if ( fPathOwnedByImage && (fPath != NULL) ) 
-		delete [] fPath;
-}
-
-void ImageLoader::setFileInfo(dev_t device, ino_t inode, time_t modDate)
-{
+uintptr_t								Segment::fgNextPIEDylibAddress = 0;
+
+
+void ImageLoader::init(const char* path, uint64_t offsetInFat, dev_t device, ino_t inode, time_t modDate)
+{
+	fPathHash = 0;
+	fPath = path;
+	fLogicalPath = NULL;
 	fDevice = device;
 	fInode = inode;
 	fLastModified = modDate;
+	fOffsetInFatFile = offsetInFat;
+	fLibraries = NULL;
+	fLibrariesCount = 0;
+	fDlopenReferenceCount = 0;
+	fStaticReferenceCount = 0;
+	fDynamicReferenceCount = 0;
+	fDynamicReferences = NULL;
+	fDepth = 0;
+	fLoadOrder = fgLoadOrdinal++;
+	fState = 0;
+	fAllLibraryChecksumsAndLoadAddressesMatch = false;
+	fLeaveMapped = false;
+	fNeverUnload = false;
+	fHideSymbols = false;
+	fMatchByInstallName = false;
+	fRegisteredDOF = false;
+#if IMAGE_NOTIFY_SUPPORT
+	fAnnounced = false;
+#endif
+	fAllLazyPointersBound = false;
+	fBeingRemoved = false;
+	fAddFuncNotified = false;
+	fPathOwnedByImage = false;
+#if RECURSIVE_INITIALIZER_LOCK
+	fInitializerRecursiveLock = NULL;
+#else
+	fInitializerLock = 0;
+#endif
+	if ( fPath != NULL )
+		fPathHash = hash(fPath);
+}
+
+
+ImageLoader::ImageLoader(const char* path, uint64_t offsetInFat, const struct stat& info)
+{
+	init(path, offsetInFat, info.st_dev, info.st_ino, info.st_mtime);
+}
+
+ImageLoader::ImageLoader(const char* moduleName)
+{
+	init(moduleName, 0, 0, 0, 0);
+}
+
+
+ImageLoader::~ImageLoader()
+{
+	if ( fPathOwnedByImage && (fPath != NULL) ) 
+		delete [] fPath;
+	if ( fLogicalPath != NULL ) 
+		delete [] fLogicalPath;
+	if ( fLibraries != NULL ) {
+		for (uint32_t i = 0; i < fLibrariesCount; ++i) {
+			if ( fLibraries[i].image != NULL )
+				fLibraries[i].image->fStaticReferenceCount--;
+		}
+		delete [] fLibraries;
+	}
+	if ( fDynamicReferences != NULL ) {
+		for (std::set<const ImageLoader*>::iterator it = fDynamicReferences->begin(); it != fDynamicReferences->end(); ++it ) {
+			const_cast<ImageLoader*>(*it)->fDynamicReferenceCount--;
+		}
+		delete fDynamicReferences;
+	}
 }
 
 void ImageLoader::setMapped(const LinkContext& context)
 {
 	fState = dyld_image_state_mapped;
-	context.notifySingle(dyld_image_state_mapped, this, NULL);  // note: can throw exception
+	context.notifySingle(dyld_image_state_mapped, this->machHeader(), fPath, fLastModified);
+}
+
+void ImageLoader::addDynamicReference(const ImageLoader* target)
+{
+	if ( fDynamicReferences == NULL )
+		fDynamicReferences = new std::set<const ImageLoader*>();
+	if ( fDynamicReferences->count(target) == 0 ) {	
+		fDynamicReferences->insert(target);
+		const_cast<ImageLoader*>(target)->fDynamicReferenceCount++;
+	}
+	//dyld::log("dyld: addDynamicReference() from %s to %s, fDynamicReferences->size()=%lu\n", this->getPath(), target->getPath(), fDynamicReferences->size());
 }
 
 int ImageLoader::compare(const ImageLoader* right) const
@@ -139,7 +178,6 @@
 	strcpy((char*)fPath, path);
 	fPathOwnedByImage = true;  // delete fPath when this image is destructed
 	fPathHash = hash(fPath);
-	fRealPath = NULL;
 }
 
 void ImageLoader::setPathUnowned(const char* path)
@@ -152,21 +190,29 @@
 	fPathHash = hash(fPath);
 }
 
-void ImageLoader::setPaths(const char* path, const char* realPath)
-{
-	this->setPath(path);
-	fRealPath = new char[strlen(realPath)+1];
-	strcpy((char*)fRealPath, realPath);
-}
-
-const char* ImageLoader::getRealPath() const 
-{ 
-	if ( fRealPath != NULL ) 
-		return fRealPath;
+void ImageLoader::setLogicalPath(const char* path)
+{
+	if ( fPath == NULL ) {
+		// no physical path set yet, so use this path as physical
+		this->setPath(path);
+	}
+	else if ( strcmp(path, fPath) == 0 ) {
+		// do not set logical path because it is the same as the physical path
+		fLogicalPath = NULL;
+	}
+	else {
+		fLogicalPath = new char[strlen(path)+1];
+		strcpy((char*)fLogicalPath, path);
+	}
+}
+
+const char* ImageLoader::getLogicalPath() const
+{
+	if ( fLogicalPath != NULL )
+		return fLogicalPath;
 	else
-		return fPath; 
-}
-
+		return fPath;
+}
 
 uint32_t ImageLoader::hash(const char* path)
 {
@@ -194,20 +240,20 @@
 	return ( (this->fDevice == stat_buf.st_dev) && (this->fInode == stat_buf.st_ino) );	
 }
 
-const char* ImageLoader::shortName(const char* fullName)
+const char* ImageLoader::getShortName() const
 {
 	// try to return leaf name
-	if ( fullName != NULL ) {
-		const char* s = strrchr(fullName, '/');
+	if ( fPath != NULL ) {
+		const char* s = strrchr(fPath, '/');
 		if ( s != NULL ) 
 			return &s[1];
 	}
-	return fullName;
-}
-
-const char* ImageLoader::getShortName() const
-{
-	return shortName(fPath);
+	return fPath; 
+}
+
+uint64_t ImageLoader::getOffsetInFatFile() const
+{
+	return fOffsetInFatFile;
 }
 
 void ImageLoader::setLeaveMapped()
@@ -237,10 +283,13 @@
 
 bool ImageLoader::containsAddress(const void* addr) const
 {
-	for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
-		const uint8_t* start = (const uint8_t*)segActualLoadAddress(i);
-		const uint8_t* end = (const uint8_t*)segActualEndAddress(i);
-		if ( (start <= addr) && (addr < end) && !segUnaccessible(i) )
+	if ( ! this->isLinked() )
+		return false;
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
+		const uint8_t* start = (const uint8_t*)seg->getActualLoadAddress(this);
+		const uint8_t* end = start + seg->getSize();
+		if ( (start <= addr) && (addr < end) && !seg->unaccessible() )
 			return true;
 	}
 	return false;
@@ -248,16 +297,10 @@
 
 bool ImageLoader::overlapsWithAddressRange(const void* start, const void* end) const
 {
-	for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
-		const uint8_t* segStart = (const uint8_t*)segActualLoadAddress(i);
-		const uint8_t* segEnd = (const uint8_t*)segActualEndAddress(i);
-		if ( strcmp(segName(i), "__UNIXSTACK") == 0 ) {
-			// __UNIXSTACK never slides.  This is the only place that cares
-			// and checking for that segment name in segActualLoadAddress()
-			// is too expensive.
-			segStart -= getSlide();
-			segEnd -= getSlide();
-		}
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
+		const uint8_t* segStart = (const uint8_t*)(seg->getActualLoadAddress(this));
+		const uint8_t* segEnd = segStart + seg->getSize();
 		if ( (start <= segStart) && (segStart < end) )
 			return true;
 		if ( (start <= segEnd) && (segEnd < end) )
@@ -270,22 +313,13 @@
 
 void ImageLoader::getMappedRegions(MappedRegion*& regions) const
 {
-	for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
 		MappedRegion region;
-		region.address = segActualLoadAddress(i);
-		region.size = segSize(i);
+		region.address = seg->getActualLoadAddress(this);
+		region.size = seg->getSize();
 		*regions++ = region;
 	}
-}
-
-
-
-bool ImageLoader::dependsOn(ImageLoader* image) {
-	for(unsigned int i=0; i < libraryCount(); ++i) {
-		if ( libImage(i) == image )
-			return true;
-	}
-	return false;
 }
 
 
@@ -297,48 +331,37 @@
 	return true;
 }
 
-bool ImageLoader::findExportedSymbolAddress(const LinkContext& context, const char* symbolName,
-											const ImageLoader* requestorImage, int requestorOrdinalOfDef,
-											bool runResolver, const ImageLoader** foundIn, uintptr_t* address) const
-{
-	const Symbol* sym = this->findExportedSymbol(symbolName, true, foundIn);
-	if ( sym != NULL ) {
-		*address = (*foundIn)->getExportedSymbolAddress(sym, context, requestorImage, runResolver);
-		return true;
-	}
-	return false;
-}
-
 
 // private method that handles circular dependencies by only search any image once
 const ImageLoader::Symbol* ImageLoader::findExportedSymbolInDependentImagesExcept(const char* name, 
 			const ImageLoader** dsiStart, const ImageLoader**& dsiCur, const ImageLoader** dsiEnd, const ImageLoader** foundIn) const
 {
 	const ImageLoader::Symbol* sym;
+	
 	// search self
 	if ( notInImgageList(this, dsiStart, dsiCur) ) {
-		sym = this->findExportedSymbol(name, false, this->getPath(), foundIn);
+		sym = this->findExportedSymbol(name, NULL, false, foundIn);
 		if ( sym != NULL )
 			return sym;
 		*dsiCur++ = this;
 	}
 
 	// search directly dependent libraries
-	for(unsigned int i=0; i < libraryCount(); ++i) {
-		ImageLoader* dependentImage = libImage(i);
+	for (uint32_t i=0; i < fLibrariesCount; ++i) {
+		ImageLoader* dependentImage = fLibraries[i].image;
 		if ( (dependentImage != NULL) && notInImgageList(dependentImage, dsiStart, dsiCur) ) {
-			sym = dependentImage->findExportedSymbol(name, false, libPath(i), foundIn);
+			const ImageLoader::Symbol* sym = dependentImage->findExportedSymbol(name, NULL, false, foundIn);
 			if ( sym != NULL )
 				return sym;
 		}
 	}
 	
 	// search indirectly dependent libraries
-	for(unsigned int i=0; i < libraryCount(); ++i) {
-		ImageLoader* dependentImage = libImage(i);
+	for (uint32_t i=0; i < fLibrariesCount; ++i) {
+		ImageLoader* dependentImage = fLibraries[i].image;
 		if ( (dependentImage != NULL) && notInImgageList(dependentImage, dsiStart, dsiCur) ) {
 			*dsiCur++ = dependentImage; 
-			sym = dependentImage->findExportedSymbolInDependentImagesExcept(name, dsiStart, dsiCur, dsiEnd, foundIn);
+			const ImageLoader::Symbol* sym = dependentImage->findExportedSymbolInDependentImagesExcept(name, dsiStart, dsiCur, dsiEnd, foundIn);
 			if ( sym != NULL )
 				return sym;
 		}
@@ -350,7 +373,7 @@
 
 const ImageLoader::Symbol* ImageLoader::findExportedSymbolInDependentImages(const char* name, const LinkContext& context, const ImageLoader** foundIn) const
 {
-	unsigned int imageCount = context.imageCount()+2;
+	unsigned int imageCount = context.imageCount();
 	const ImageLoader* dontSearchImages[imageCount];
 	dontSearchImages[0] = this; // don't search this image
 	const ImageLoader** cur = &dontSearchImages[1];
@@ -359,67 +382,21 @@
 
 const ImageLoader::Symbol* ImageLoader::findExportedSymbolInImageOrDependentImages(const char* name, const LinkContext& context, const ImageLoader** foundIn) const
 {
-	unsigned int imageCount = context.imageCount()+2;
+	unsigned int imageCount = context.imageCount();
 	const ImageLoader* dontSearchImages[imageCount];
 	const ImageLoader** cur = &dontSearchImages[0];
 	return this->findExportedSymbolInDependentImagesExcept(name, &dontSearchImages[0], cur, &dontSearchImages[imageCount], foundIn);
 }
 
-// this is called by initializeMainExecutable() to interpose on the initial set of images
-void ImageLoader::applyInterposing(const LinkContext& context)
-{
-	if ( fgInterposingTuples.size() != 0 )
-		this->recursiveApplyInterposing(context);
-}
-
-
-uintptr_t ImageLoader::interposedAddress(const LinkContext& context, uintptr_t address, const ImageLoader* inImage, const ImageLoader* onlyInImage)
-{
-	//dyld::log("interposedAddress(0x%08llX), tupleCount=%lu\n", (uint64_t)address, fgInterposingTuples.size());
-	for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
-		//dyld::log("    interposedAddress: replacee=0x%08llX, replacement=0x%08llX, neverImage=%p, onlyImage=%p, inImage=%p\n", 
-		//				(uint64_t)it->replacee, (uint64_t)it->replacement,  it->neverImage, it->onlyImage, inImage);
-		// replace all references to 'replacee' with 'replacement'
-		if ( (address == it->replacee) && (inImage != it->neverImage) && ((it->onlyImage == NULL) || (inImage == it->onlyImage)) ) {
-			if ( context.verboseInterposing ) {
-				dyld::log("dyld interposing: replace 0x%lX with 0x%lX\n", it->replacee, it->replacement);
-			}
-			return it->replacement;
-		}
-	}
-	return address;
-}
-
-void ImageLoader::addDynamicInterposingTuples(const struct dyld_interpose_tuple array[], size_t count)
-{
-	for(size_t i=0; i < count; ++i) {
-		ImageLoader::InterposeTuple tuple;
-		tuple.replacement		= (uintptr_t)array[i].replacement;
-		tuple.neverImage		= NULL;
-		tuple.onlyImage		    = this;
-		tuple.replacee			= (uintptr_t)array[i].replacee;
-		// chain to any existing interpositions
-		for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
-			if ( (it->replacee == tuple.replacee) && (it->onlyImage == this) ) {
-				tuple.replacee = it->replacement;
-			}
-		}
-		ImageLoader::fgInterposingTuples.push_back(tuple);
-	}
-}
-
-
-void ImageLoader::link(const LinkContext& context, bool forceLazysBound, bool preflightOnly, bool neverUnload, const RPathChain& loaderRPaths, const char* imagePath)
-{
-	//dyld::log("ImageLoader::link(%s) refCount=%d, neverUnload=%d\n", imagePath, fDlopenReferenceCount, fNeverUnload);
-	
-	// clear error strings
-	(*context.setErrorStrings)(0, NULL, NULL, NULL);
-
+
+void ImageLoader::link(const LinkContext& context, bool forceLazysBound, bool preflightOnly, const RPathChain& loaderRPaths)
+{
+	//dyld::log("ImageLoader::link(%s) refCount=%d, neverUnload=%d\n", this->getPath(), fStaticReferenceCount, fNeverUnload);
+	
 	uint64_t t0 = mach_absolute_time();
-	this->recursiveLoadLibraries(context, preflightOnly, loaderRPaths, imagePath);
-	context.notifyBatch(dyld_image_state_dependents_mapped, preflightOnly);
-
+	this->recursiveLoadLibraries(context,loaderRPaths);
+	context.notifyBatch(dyld_image_state_dependents_mapped);
+	
 	// we only do the loading step for preflights
 	if ( preflightOnly )
 		return;
@@ -430,46 +407,31 @@
 
 	uint64_t t2 = mach_absolute_time();
  	this->recursiveRebase(context);
-	context.notifyBatch(dyld_image_state_rebased, false);
+	context.notifyBatch(dyld_image_state_rebased);
 	
 	uint64_t t3 = mach_absolute_time();
- 	this->recursiveBind(context, forceLazysBound, neverUnload);
-
-	uint64_t t4 = mach_absolute_time();
-	if ( !context.linkingMainExecutable )
-		this->weakBind(context);
-	uint64_t t5 = mach_absolute_time();	
-
-	context.notifyBatch(dyld_image_state_bound, false);
-	uint64_t t6 = mach_absolute_time();	
-
+ 	this->recursiveBind(context, forceLazysBound);
+	context.notifyBatch(dyld_image_state_bound);
+
+	uint64_t t4 = mach_absolute_time();	
 	std::vector<DOFInfo> dofs;
 	this->recursiveGetDOFSections(context, dofs);
 	context.registerDOFs(dofs);
-	uint64_t t7 = mach_absolute_time();	
-
-	// interpose any dynamically loaded images
-	if ( !context.linkingMainExecutable && (fgInterposingTuples.size() != 0) ) {
-		this->recursiveApplyInterposing(context);
-	}
-	
-	// clear error strings
-	(*context.setErrorStrings)(0, NULL, NULL, NULL);
-
+
+	
 	fgTotalLoadLibrariesTime += t1 - t0;
 	fgTotalRebaseTime += t3 - t2;
 	fgTotalBindTime += t4 - t3;
-	fgTotalWeakBindTime += t5 - t4;
-	fgTotalDOF += t7 - t6;
 	
 	// done with initial dylib loads
-	fgNextPIEDylibAddress = 0;
+	Segment::fgNextPIEDylibAddress = 0;
 }
 
 
 void ImageLoader::printReferenceCounts()
 {
-	dyld::log("      dlopen=%d for %s\n", fDlopenReferenceCount, getPath() );
+	dyld::log("      dlopen=%d, static=%d, dynamic=%d for %s\n", 
+				fDlopenReferenceCount, fStaticReferenceCount, fDynamicReferenceCount, getPath() );
 }
 
 
@@ -481,39 +443,18 @@
 	return false;
 }
 
-
-// <rdar://problem/14412057> upward dylib initializers can be run too soon
-// To handle dangling dylibs which are upward linked but not downward, all upward linked dylibs
-// have their initialization postponed until after the recursion through downward dylibs
-// has completed.
-void ImageLoader::processInitializers(const LinkContext& context, mach_port_t thisThread,
-									 InitializerTimingList& timingInfo, ImageLoader::UninitedUpwards& images)
-{
-	uint32_t maxImageCount = context.imageCount()+2;
-	ImageLoader::UninitedUpwards upsBuffer[maxImageCount];
-	ImageLoader::UninitedUpwards& ups = upsBuffer[0];
-	ups.count = 0;
-	// Calling recursive init on all images in images list, building a new list of
-	// uninitialized upward dependencies.
-	for (uintptr_t i=0; i < images.count; ++i) {
-		images.images[i]->recursiveInitialization(context, thisThread, images.images[i]->getPath(), timingInfo, ups);
-	}
-	// If any upward dependencies remain, init them.
-	if ( ups.count > 0 )
-		processInitializers(context, thisThread, timingInfo, ups);
-}
-
-
-void ImageLoader::runInitializers(const LinkContext& context, InitializerTimingList& timingInfo)
-{
+void ImageLoader::runInitializers(const LinkContext& context)
+{
+#if IMAGE_NOTIFY_SUPPORT
+	ImageLoader* newImages[context.imageCount()];
+	ImageLoader** end = newImages;
+	this->recursiveImageAnnouncement(context, end);	 // build bottom up list images being added
+	context.notifyAdding(newImages, end-newImages);	// tell anyone who cares about these
+#endif
+
 	uint64_t t1 = mach_absolute_time();
-	mach_port_t thisThread = mach_thread_self();
-	ImageLoader::UninitedUpwards up;
-	up.count = 1;
-	up.images[0] = this;
-	processInitializers(context, thisThread, timingInfo, up);
-	context.notifyBatch(dyld_image_state_initialized, false);
-	mach_port_deallocate(mach_task_self(), thisThread);
+	this->recursiveInitialization(context, mach_thread_self());
+	context.notifyBatch(dyld_image_state_initialized);
 	uint64_t t2 = mach_absolute_time();
 	fgTotalInitTime += (t2 - t1);
 }
@@ -526,10 +467,10 @@
 
 		if ( recursive ) {
 			// bind lower level libraries first
-			for(unsigned int i=0; i < libraryCount(); ++i) {
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL )
-					dependentImage->bindAllLazyPointers(context, recursive);
+			for(unsigned int i=0; i < fLibrariesCount; ++i){
+				DependentLibrary& libInfo = fLibraries[i];
+				if ( libInfo.image != NULL )
+					libInfo.image->bindAllLazyPointers(context, recursive);
 			}
 		}
 		// bind lazies in this image
@@ -538,34 +479,88 @@
 }
 
 
+intptr_t ImageLoader::assignSegmentAddresses(const LinkContext& context)
+{
+	// preflight and calculate slide if needed
+	intptr_t slide = 0;
+	if ( this->segmentsCanSlide() && this->segmentsMustSlideTogether() ) {
+		bool needsToSlide = false;
+		uintptr_t lowAddr = UINTPTR_MAX;
+		uintptr_t highAddr = 0;
+		for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+			Segment* seg = *it;
+			const uintptr_t segLow = seg->getPreferredLoadAddress();
+			const uintptr_t segHigh = (segLow + seg->getSize() + 4095) & -4096;
+			if ( segLow < lowAddr )
+				lowAddr = segLow;
+			if ( segHigh > highAddr )
+				highAddr = segHigh;
+				
+			if ( !seg->hasPreferredLoadAddress() || !Segment::reserveAddressRange(seg->getPreferredLoadAddress(), seg->getSize()) )
+				needsToSlide = true;
+		}
+		if ( needsToSlide ) {
+			// find a chunk of address space to hold all segments
+			uintptr_t addr = Segment::reserveAnAddressRange(highAddr-lowAddr, context);
+			slide = addr - lowAddr;
+		}
+	} 
+	else if ( ! this->segmentsCanSlide() ) {
+		for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+			Segment* seg = *it;
+			if ( strcmp(seg->getName(), "__PAGEZERO") == 0 )
+				continue;
+			if ( !Segment::reserveAddressRange(seg->getPreferredLoadAddress(), seg->getSize()) )
+				throw "can't map";
+		}
+	}
+	else {
+		// mach-o does not support independently sliding segments
+	}
+	return slide;
+}
+
+
+void ImageLoader::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
+{
+	if ( context.verboseMapping )
+		dyld::log("dyld: Mapping %s\n", this->getPath());
+	// find address range for image
+	intptr_t slide = this->assignSegmentAddresses(context);
+	// map in all segments
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
+		seg->map(fd, offsetInFat, slide, this, context);		
+	}
+	// update slide to reflect load location			
+	this->setSlide(slide);
+}
+
+void ImageLoader::mapSegments(const void* memoryImage, uint64_t imageLen, const LinkContext& context)
+{
+	if ( context.verboseMapping )
+		dyld::log("dyld: Mapping memory %p\n", memoryImage);
+	// find address range for image
+	intptr_t slide = this->assignSegmentAddresses(context);
+	// map in all segments
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
+		seg->map(memoryImage, slide, this, context);		
+	}
+	// update slide to reflect load location			
+	this->setSlide(slide);
+	// set R/W permissions on all segments at slide location
+	for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
+		Segment* seg = *it;
+		seg->setPermissions(context, this);		
+	}
+}
+
 bool ImageLoader::allDependentLibrariesAsWhenPreBound() const
 {
 	return fAllLibraryChecksumsAndLoadAddressesMatch;
 }
 
-
-void ImageLoader::markedUsedRecursive(const std::vector<DynamicReference>& dynamicReferences)
-{
-	// already visited here
-	if ( fMarkedInUse )
-		return;
-	fMarkedInUse = true;
-	
-	// clear mark on all statically dependent dylibs
-	for(unsigned int i=0; i < libraryCount(); ++i) {
-		ImageLoader* dependentImage = libImage(i);
-		if ( dependentImage != NULL ) {
-			dependentImage->markedUsedRecursive(dynamicReferences);
-		}
-	}
-	
-	// clear mark on all dynamically dependent dylibs
-	for (std::vector<ImageLoader::DynamicReference>::const_iterator it=dynamicReferences.begin(); it != dynamicReferences.end(); ++it) {
-		if ( it->from == this )
-			it->to->markedUsedRecursive(dynamicReferences);
-	}
-	
-}
 
 unsigned int ImageLoader::recursiveUpdateDepth(unsigned int maxDepth)
 {
@@ -578,10 +573,10 @@
 		
 		// get depth of dependents
 		unsigned int minDependentDepth = maxDepth;
-		for(unsigned int i=0; i < libraryCount(); ++i) {
-			ImageLoader* dependentImage = libImage(i);
-			if ( (dependentImage != NULL) && !libIsUpward(i) ) {
-				unsigned int d = dependentImage->recursiveUpdateDepth(maxDepth);
+		for(unsigned int i=0; i < fLibrariesCount; ++i) {
+			DependentLibrary& libInfo = fLibraries[i];
+			if ( libInfo.image != NULL ) {
+				unsigned int d = libInfo.image->recursiveUpdateDepth(maxDepth);
 				if ( d < minDependentDepth )
 					minDependentDepth = d;
 			}
@@ -595,14 +590,17 @@
 }
 
 
-void ImageLoader::recursiveLoadLibraries(const LinkContext& context, bool preflightOnly, const RPathChain& loaderRPaths, const char* loadPath)
+void ImageLoader::recursiveLoadLibraries(const LinkContext& context, const RPathChain& loaderRPaths)
 {
 	if ( fState < dyld_image_state_dependents_mapped ) {
 		// break cycles
 		fState = dyld_image_state_dependents_mapped;
 		
 		// get list of libraries this image needs
-		DependentLibraryInfo libraryInfos[fLibraryCount]; 
+		fLibrariesCount = this->doGetDependentLibraryCount();
+		fLibraries = new DependentLibrary[fLibrariesCount];
+		bzero(fLibraries, sizeof(DependentLibrary)*fLibrariesCount);
+		DependentLibraryInfo libraryInfos[fLibrariesCount]; 
 		this->doGetDependentLibraries(libraryInfos);
 		
 		// get list of rpaths that this image adds
@@ -612,112 +610,74 @@
 		
 		// try to load each
 		bool canUsePrelinkingInfo = true; 
-		for(unsigned int i=0; i < fLibraryCount; ++i){
-			ImageLoader* dependentLib;
-			bool depLibReExported = false;
-			bool depLibRequired = false;
-			bool depLibCheckSumsMatch = false;
+		for(unsigned int i=0; i < fLibrariesCount; ++i){
+			DependentLibrary& requiredLib = fLibraries[i];
 			DependentLibraryInfo& requiredLibInfo = libraryInfos[i];
-#if DYLD_SHARED_CACHE_SUPPORT
-			if ( preflightOnly && context.inSharedCache(requiredLibInfo.name) ) {
-				// <rdar://problem/5910137> dlopen_preflight() on image in shared cache leaves it loaded but not objc initialized
-				// in preflight mode, don't even load dylib that are in the shared cache because they will never be unloaded
-				setLibImage(i, NULL, false, false);
-				continue;
-			}
-#endif
 			try {
-				unsigned cacheIndex;
-				dependentLib = context.loadLibrary(requiredLibInfo.name, true, this->getPath(), &thisRPaths, cacheIndex);
-				if ( dependentLib == this ) {
+				bool depNamespace = false;
+				requiredLib.image = context.loadLibrary(requiredLibInfo.name, true, depNamespace, this->getPath(), &thisRPaths);
+				if ( requiredLib.image == this ) {
 					// found circular reference, perhaps DYLD_LIBARY_PATH is causing this rdar://problem/3684168 
-					dependentLib = context.loadLibrary(requiredLibInfo.name, false, NULL, NULL, cacheIndex);
-					if ( dependentLib != this )
+					requiredLib.image = context.loadLibrary(requiredLibInfo.name, false, depNamespace, NULL, NULL);
+					if ( requiredLib.image != this )
 						dyld::warn("DYLD_ setting caused circular dependency in %s\n", this->getPath());
 				}
 				if ( fNeverUnload )
-					dependentLib->setNeverUnload();
-				if ( requiredLibInfo.upward ) {
-				}
-				else { 
-					dependentLib->fIsReferencedDownward = true;
-				}
-				LibraryInfo actualInfo = dependentLib->doGetLibraryInfo(requiredLibInfo.info);
-				depLibRequired = requiredLibInfo.required;
-				depLibCheckSumsMatch = ( actualInfo.checksum == requiredLibInfo.info.checksum );
-				depLibReExported = requiredLibInfo.reExported;
-				if ( ! depLibReExported ) {
-					// for pre-10.5 binaries that did not use LC_REEXPORT_DYLIB
-					depLibReExported = dependentLib->isSubframeworkOf(context, this) || this->hasSubLibrary(context, dependentLib);
+					requiredLib.image->setNeverUnload();
+				requiredLib.image->fStaticReferenceCount += 1;
+				LibraryInfo actualInfo = requiredLib.image->doGetLibraryInfo();
+				requiredLib.required = requiredLibInfo.required;
+				requiredLib.checksumMatches = ( actualInfo.checksum == requiredLibInfo.info.checksum );
+				requiredLib.isReExported = requiredLibInfo.reExported;
+				if ( ! requiredLib.isReExported ) {
+					requiredLib.isSubFramework = requiredLib.image->isSubframeworkOf(context, this);
+					requiredLib.isReExported = requiredLib.isSubFramework || this->hasSubLibrary(context, requiredLib.image);
 				}
 				// check found library version is compatible
-				// <rdar://problem/89200806> 0xFFFFFFFF is wildcard that matches any version
-				if ( (requiredLibInfo.info.minVersion != 0xFFFFFFFF) && (actualInfo.minVersion < requiredLibInfo.info.minVersion) ) {
-					// record values for possible use by CrashReporter or Finder
+				if ( actualInfo.minVersion < requiredLibInfo.info.minVersion ) {
 					dyld::throwf("Incompatible library version: %s requires version %d.%d.%d or later, but %s provides version %d.%d.%d",
 							this->getShortName(), requiredLibInfo.info.minVersion >> 16, (requiredLibInfo.info.minVersion >> 8) & 0xff, requiredLibInfo.info.minVersion & 0xff,
-							dependentLib->getShortName(), actualInfo.minVersion >> 16, (actualInfo.minVersion >> 8) & 0xff, actualInfo.minVersion & 0xff);
+							requiredLib.image->getShortName(), actualInfo.minVersion >> 16, (actualInfo.minVersion >> 8) & 0xff, actualInfo.minVersion & 0xff);
 				}
-				// prebinding for this image disabled if any dependent library changed
-				//if ( !depLibCheckSumsMatch )
-				//	canUsePrelinkingInfo = false;
-				// prebinding for this image disabled unless both this and dependent are in the shared cache
-				if ( !dependentLib->inSharedCache() || !this->inSharedCache() )
+				// prebinding for this image disabled if any dependent library changed or slid
+				if ( !requiredLib.checksumMatches || (requiredLib.image->getSlide() != 0) )
 					canUsePrelinkingInfo = false;
-					
 				//if ( context.verbosePrebinding ) {
 				//	if ( !requiredLib.checksumMatches )
 				//		fprintf(stderr, "dyld: checksum mismatch, (%u v %u) for %s referencing %s\n", 
-				//			requiredLibInfo.info.checksum, actualInfo.checksum, this->getPath(), 	dependentLib->getPath());		
-				//	if ( dependentLib->getSlide() != 0 )
-				//		fprintf(stderr, "dyld: dependent library slid for %s referencing %s\n", this->getPath(), dependentLib->getPath());		
+				//			requiredLibInfo.info.checksum, actualInfo.checksum, this->getPath(), 	requiredLib.image->getPath());		
+				//	if ( requiredLib.image->getSlide() != 0 )
+				//		fprintf(stderr, "dyld: dependent library slid for %s referencing %s\n", this->getPath(), requiredLib.image->getPath());		
 				//}
 			}
 			catch (const char* msg) {
 				//if ( context.verbosePrebinding )
-				//	fprintf(stderr, "dyld: exception during processing for %s referencing %s\n", this->getPath(), dependentLib->getPath());		
+				//	fprintf(stderr, "dyld: exception during processing for %s referencing %s\n", this->getPath(), requiredLib.image->getPath());		
 				if ( requiredLibInfo.required ) {
 					fState = dyld_image_state_mapped;
-					// record values for possible use by CrashReporter or Finder
-					if ( strstr(msg, "Incompatible library version") != NULL )
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_DYLIB_WRONG_VERSION, this->getPath(), requiredLibInfo.name, NULL);
-					else if ( strstr(msg, "architecture") != NULL )
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_DYLIB_WRONG_ARCH, this->getPath(), requiredLibInfo.name, NULL);
-					else if ( strstr(msg, "file system sandbox") != NULL )
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_FILE_SYSTEM_SANDBOX, this->getPath(), requiredLibInfo.name, NULL);
-					else if ( strstr(msg, "code signature") != NULL )
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_CODE_SIGNATURE, this->getPath(), requiredLibInfo.name, NULL);
-					else if ( strstr(msg, "malformed") != NULL )
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_MALFORMED_MACHO, this->getPath(), requiredLibInfo.name, NULL);
-					else
-						(*context.setErrorStrings)(DYLD_EXIT_REASON_DYLIB_MISSING, this->getPath(), requiredLibInfo.name, NULL);
-					const char* newMsg = dyld::mkstringf("Library not loaded: %s\n  Referenced from: %s\n  Reason: %s", requiredLibInfo.name, this->getRealPath(), msg);
-					free((void*)msg); 	// our free() will do nothing if msg is a string literal
-					throw newMsg;
+					dyld::throwf("Library not loaded: %s\n  Referenced from: %s\n  Reason: %s", requiredLibInfo.name, this->getPath(), msg);
 				}
-				free((void*)msg); 	// our free() will do nothing if msg is a string literal
 				// ok if weak library not found
-				dependentLib = NULL;
+				requiredLib.image = NULL;
 				canUsePrelinkingInfo = false;  // this disables all prebinding, we may want to just slam import vectors for this lib to zero
 			}
-			setLibImage(i, dependentLib, depLibReExported, requiredLibInfo.upward);
 		}
 		fAllLibraryChecksumsAndLoadAddressesMatch = canUsePrelinkingInfo;
 
 		// tell each to load its dependents
-		for(unsigned int i=0; i < libraryCount(); ++i) {
-			ImageLoader* dependentImage = libImage(i);
-			if ( dependentImage != NULL ) {	
-				dependentImage->recursiveLoadLibraries(context, preflightOnly, thisRPaths, libraryInfos[i].name);
+		for(unsigned int i=0; i < fLibrariesCount; ++i){
+			DependentLibrary& lib = fLibraries[i];
+			if ( lib.image != NULL ) {	
+				lib.image->recursiveLoadLibraries(context, thisRPaths);
 			}
 		}
 		
 		// do deep prebind check
 		if ( fAllLibraryChecksumsAndLoadAddressesMatch ) {
-			for(unsigned int i=0; i < libraryCount(); ++i){
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL ) {	
-					if ( !dependentImage->allDependentLibrariesAsWhenPreBound() )
+			for(unsigned int i=0; i < fLibrariesCount; ++i){
+				const DependentLibrary& libInfo = fLibraries[i];
+				if ( libInfo.image != NULL ) {
+					if ( !libInfo.image->allDependentLibrariesAsWhenPreBound() )
 						fAllLibraryChecksumsAndLoadAddressesMatch = false;
 				}
 			}
@@ -740,55 +700,30 @@
 		
 		try {
 			// rebase lower level libraries first
-			for(unsigned int i=0; i < libraryCount(); ++i) {
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL )
-					dependentImage->recursiveRebase(context);
+			for(unsigned int i=0; i < fLibrariesCount; ++i){
+				DependentLibrary& libInfo = fLibraries[i];
+				if ( libInfo.image != NULL )
+					libInfo.image->recursiveRebase(context);
 			}
 				
 			// rebase this image
 			doRebase(context);
 			
 			// notify
-			context.notifySingle(dyld_image_state_rebased, this, NULL);
+			context.notifySingle(dyld_image_state_rebased, this->machHeader(), fPath, fLastModified);
 		}
 		catch (const char* msg) {
 			// this image is not rebased
 			fState = dyld_image_state_dependents_mapped;
-            CRSetCrashLogMessage2(NULL);
 			throw;
 		}
 	}
 }
 
-void ImageLoader::recursiveApplyInterposing(const LinkContext& context)
-{ 
-	if ( ! fInterposed ) {
-		// break cycles
-		fInterposed = true;
-		
-		try {
-			// interpose lower level libraries first
-			for(unsigned int i=0; i < libraryCount(); ++i) {
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL )
-					dependentImage->recursiveApplyInterposing(context);
-			}
-				
-			// interpose this image
-			doInterpose(context);
-		}
-		catch (const char* msg) {
-			// this image is not interposed
-			fInterposed = false;
-			throw;
-		}
-	}
-}
-
-
-
-void ImageLoader::recursiveBind(const LinkContext& context, bool forceLazysBound, bool neverUnload)
+
+
+
+void ImageLoader::recursiveBind(const LinkContext& context, bool forceLazysBound)
 {
 	// Normally just non-lazy pointers are bound immediately.
 	// The exceptions are:
@@ -800,154 +735,53 @@
 	
 		try {
 			// bind lower level libraries first
-			for(unsigned int i=0; i < libraryCount(); ++i) {
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL )
-					dependentImage->recursiveBind(context, forceLazysBound, neverUnload);
+			for(unsigned int i=0; i < fLibrariesCount; ++i){
+				DependentLibrary& libInfo = fLibraries[i];
+				if ( libInfo.image != NULL )
+					libInfo.image->recursiveBind(context, forceLazysBound);
 			}
 			// bind this image
 			this->doBind(context, forceLazysBound);	
+			this->doUpdateMappingPermissions(context);
 			// mark if lazys are also bound
 			if ( forceLazysBound || this->usablePrebinding(context) )
 				fAllLazyPointersBound = true;
-			// mark as never-unload if requested
-			if ( neverUnload )
-				this->setNeverUnload();
 				
-			context.notifySingle(dyld_image_state_bound, this, NULL);
+			context.notifySingle(dyld_image_state_bound, this->machHeader(), fPath, fLastModified);
 		}
 		catch (const char* msg) {
 			// restore state
 			fState = dyld_image_state_rebased;
-            CRSetCrashLogMessage2(NULL);
 			throw;
 		}
 	}
 }
 
-void ImageLoader::weakBind(const LinkContext& context)
-{
-	if ( context.verboseWeakBind )
-		dyld::log("dyld: weak bind start:\n");
-	uint64_t t1 = mach_absolute_time();
-	// get set of ImageLoaders that participate in coalecsing
-	ImageLoader* imagesNeedingCoalescing[fgImagesRequiringCoalescing];
-	unsigned imageIndexes[fgImagesRequiringCoalescing];
-	int count = context.getCoalescedImages(imagesNeedingCoalescing, imageIndexes);
-	
-	// count how many have not already had weakbinding done
-	int countNotYetWeakBound = 0;
-	int countOfImagesWithWeakDefinitionsNotInSharedCache = 0;
-	for(int i=0; i < count; ++i) {
-		if ( ! imagesNeedingCoalescing[i]->weakSymbolsBound(imageIndexes[i]) )
-			++countNotYetWeakBound;
-		if ( ! imagesNeedingCoalescing[i]->inSharedCache() )
-			++countOfImagesWithWeakDefinitionsNotInSharedCache;
-	}
-
-	// don't need to do any coalescing if only one image has overrides, or all have already been done
-	if ( (countOfImagesWithWeakDefinitionsNotInSharedCache > 0) && (countNotYetWeakBound > 0) ) {
-		// make symbol iterators for each
-		ImageLoader::CoalIterator iterators[count];
-		ImageLoader::CoalIterator* sortedIts[count];
-		for(int i=0; i < count; ++i) {
-			imagesNeedingCoalescing[i]->initializeCoalIterator(iterators[i], i, imageIndexes[i]);
-			sortedIts[i] = &iterators[i];
-			if ( context.verboseWeakBind )
-				dyld::log("dyld: weak bind load order %d/%d for %s\n", i, count, imagesNeedingCoalescing[i]->getIndexedPath(imageIndexes[i]));
-		}
-		
-		// walk all symbols keeping iterators in sync by 
-		// only ever incrementing the iterator with the lowest symbol 
-		int doneCount = 0;
-		while ( doneCount != count ) {
-			//for(int i=0; i < count; ++i)
-			//	dyld::log("sym[%d]=%s ", sortedIts[i]->loadOrder, sortedIts[i]->symbolName);
-			//dyld::log("\n");
-			// increment iterator with lowest symbol
-			if ( sortedIts[0]->image->incrementCoalIterator(*sortedIts[0]) )
-				++doneCount; 
-			// re-sort iterators
-			for(int i=1; i < count; ++i) {
-				int result = strcmp(sortedIts[i-1]->symbolName, sortedIts[i]->symbolName);
-				if ( result == 0 )
-					sortedIts[i-1]->symbolMatches = true;
-				if ( result > 0 ) {
-					// new one is bigger then next, so swap
-					ImageLoader::CoalIterator* temp = sortedIts[i-1];
-					sortedIts[i-1] = sortedIts[i];
-					sortedIts[i] = temp;
-				}
-				if ( result < 0 )
-					break;
-			}
-			// process all matching symbols just before incrementing the lowest one that matches
-			if ( sortedIts[0]->symbolMatches && !sortedIts[0]->done ) {
-				const char* nameToCoalesce = sortedIts[0]->symbolName;
-				// pick first symbol in load order (and non-weak overrides weak)
-				uintptr_t targetAddr = 0;
-				ImageLoader* targetImage = NULL;
-				unsigned targetImageIndex = 0;
-				for(int i=0; i < count; ++i) {
-					if ( strcmp(iterators[i].symbolName, nameToCoalesce) == 0 ) {
-						if ( context.verboseWeakBind )
-							dyld::log("dyld: weak bind, found %s weak=%d in %s \n", nameToCoalesce, iterators[i].weakSymbol, iterators[i].image->getIndexedPath((unsigned)iterators[i].imageIndex));
-						if ( iterators[i].weakSymbol ) {
-							if ( targetAddr == 0 ) {
-								targetAddr = iterators[i].image->getAddressCoalIterator(iterators[i], context);
-								if ( targetAddr != 0 ) {
-									targetImage = iterators[i].image;
-									targetImageIndex = (unsigned)iterators[i].imageIndex;
-								}
-							}
-						}
-						else {
-							targetAddr = iterators[i].image->getAddressCoalIterator(iterators[i], context);
-							if ( targetAddr != 0 ) {
-								targetImage = iterators[i].image;
-								targetImageIndex = (unsigned)iterators[i].imageIndex;
-								// strong implementation found, stop searching
-								break;
-							}
-						}
-					}
-				}
-				// tell each to bind to this symbol (unless already bound)
-				if ( targetAddr != 0 ) {
-					if ( context.verboseWeakBind ) {
-						dyld::log("dyld: weak binding all uses of %s to copy from %s\n",
-									nameToCoalesce, targetImage->getIndexedShortName(targetImageIndex));
-					}
-					for(int i=0; i < count; ++i) {
-						if ( strcmp(iterators[i].symbolName, nameToCoalesce) == 0 ) {
-							if ( context.verboseWeakBind ) {
-								dyld::log("dyld: weak bind, setting all uses of %s in %s to 0x%lX from %s\n",
-											nameToCoalesce, iterators[i].image->getIndexedShortName((unsigned)iterators[i].imageIndex),
-											targetAddr, targetImage->getIndexedShortName(targetImageIndex));
-							}
-							if ( ! iterators[i].image->weakSymbolsBound(imageIndexes[i]) )
-								iterators[i].image->updateUsesCoalIterator(iterators[i], targetAddr, targetImage, targetImageIndex, context);
-							iterators[i].symbolMatches = false; 
-						}
-					}
-				}
-				
-			}
-		}
-		
-		// mark all as having all weak symbols bound
-		for(int i=0; i < count; ++i) {
-			imagesNeedingCoalescing[i]->setWeakSymbolsBound(imageIndexes[i]);
-		}
-	}
-	uint64_t t2 = mach_absolute_time();
-	fgTotalWeakBindTime += t2  - t1;
-	
-	if ( context.verboseWeakBind )
-		dyld::log("dyld: weak bind end\n");
-}
-
-
+
+#if IMAGE_NOTIFY_SUPPORT
+void ImageLoader::recursiveImageAnnouncement(const LinkContext& context, ImageLoader**& newImages)
+{
+	if ( ! fAnnounced ) {
+		// break cycles
+		fAnnounced = true;
+		
+		// announce lower level libraries first
+		for(unsigned int i=0; i < fLibrariesCount; ++i){
+			DependentLibrary& libInfo = fLibraries[i];
+			if ( libInfo.image != NULL )
+				libInfo.image->recursiveImageAnnouncement(context, newImages);
+		}
+		
+		// add to list of images to notify about
+		*newImages++ = this;
+		//dyld::log("next size = %d\n", newImages.size());
+		
+		// remember that this image wants to be notified about other images
+		 if ( this->hasImageNotification() )
+			context.addImageNeedingNotification(this);
+	}
+}
+#endif
 
 void ImageLoader::recursiveGetDOFSections(const LinkContext& context, std::vector<DOFInfo>& dofs)
 {
@@ -956,28 +790,15 @@
 		fRegisteredDOF = true;
 		
 		// gather lower level libraries first
-		for(unsigned int i=0; i < libraryCount(); ++i) {
-			ImageLoader* dependentImage = libImage(i);
-			if ( dependentImage != NULL )
-				dependentImage->recursiveGetDOFSections(context, dofs);
+		for(unsigned int i=0; i < fLibrariesCount; ++i){
+			DependentLibrary& libInfo = fLibraries[i];
+			if ( libInfo.image != NULL )
+				libInfo.image->recursiveGetDOFSections(context, dofs);
 		}
 		this->doGetDOFSections(context, dofs);
 	}
 }
 
-void ImageLoader::setNeverUnloadRecursive() {
-	if ( ! fNeverUnload ) {
-		// break cycles
-		fNeverUnload = true;
-		
-		// gather lower level libraries first
-		for(unsigned int i=0; i < libraryCount(); ++i) {
-			ImageLoader* dependentImage = libImage(i);
-			if ( dependentImage != NULL )
-				dependentImage->setNeverUnloadRecursive();
-		}
-	}
-}
 
 void ImageLoader::recursiveSpinLock(recursive_lock& rlock)
 {
@@ -998,77 +819,63 @@
 		fInitializerRecursiveLock = NULL;
 }
 
-void ImageLoader::InitializerTimingList::addTime(const char* name, uint64_t time)
-{
-	for (int i=0; i < count; ++i) {
-		if ( strcmp(images[i].shortName, name) == 0 ) {
-			images[i].initTime += time;
-			return;
-		}
-	}
-	images[count].initTime = time;
-	images[count].shortName = name;
-	++count;
-}
-
-void ImageLoader::recursiveInitialization(const LinkContext& context, mach_port_t this_thread, const char* pathToInitialize,
-										  InitializerTimingList& timingInfo, UninitedUpwards& uninitUps)
-{
+
+void ImageLoader::recursiveInitialization(const LinkContext& context, mach_port_t this_thread)
+{
+#if RECURSIVE_INITIALIZER_LOCK
 	recursive_lock lock_info(this_thread);
 	recursiveSpinLock(lock_info);
+#else
+	_spin_lock(&fInitializerLock);
+#endif
 
 	if ( fState < dyld_image_state_dependents_initialized-1 ) {
 		uint8_t oldState = fState;
 		// break cycles
 		fState = dyld_image_state_dependents_initialized-1;
+
 		try {
 			// initialize lower level libraries first
-			for(unsigned int i=0; i < libraryCount(); ++i) {
-				ImageLoader* dependentImage = libImage(i);
-				if ( dependentImage != NULL ) {
-					// don't try to initialize stuff "above" me yet
-					if ( libIsUpward(i) ) {
-						uninitUps.images[uninitUps.count] = dependentImage;
-						uninitUps.count++;
-					}
-					else if ( dependentImage->fDepth >= fDepth ) {
-						dependentImage->recursiveInitialization(context, this_thread, libPath(i), timingInfo, uninitUps);
-					}
-                }
+			for(unsigned int i=0; i < fLibrariesCount; ++i){
+				DependentLibrary& libInfo = fLibraries[i];
+				// don't try to initialize stuff "above" me
+				if ( (libInfo.image != NULL) && (libInfo.image->fDepth >= fDepth) )
+					libInfo.image->recursiveInitialization(context, this_thread);
 			}
 			
 			// record termination order
 			if ( this->needsTermination() )
 				context.terminationRecorder(this);
 			
-			// let objc know we are about to initialize this image
-			uint64_t t1 = mach_absolute_time();
+			// let objc know we are about to initalize this image
 			fState = dyld_image_state_dependents_initialized;
 			oldState = fState;
-			context.notifySingle(dyld_image_state_dependents_initialized, this, &timingInfo);
-			
+			context.notifySingle(dyld_image_state_dependents_initialized, this->machHeader(), fPath, fLastModified);
+
 			// initialize this image
-			bool hasInitializers = this->doInitialization(context);
-
-			// let anyone know we finished initializing this image
+			this->doInitialization(context);
+			// let anyone know we finished initalizing this image
 			fState = dyld_image_state_initialized;
 			oldState = fState;
-			context.notifySingle(dyld_image_state_initialized, this, NULL);
-			
-			if ( hasInitializers ) {
-				uint64_t t2 = mach_absolute_time();
-				timingInfo.addTime(this->getShortName(), t2-t1);
-			}
+			context.notifySingle(dyld_image_state_initialized, this->machHeader(), fPath, fLastModified);
 		}
 		catch (const char* msg) {
 			// this image is not initialized
 			fState = oldState;
+		#if RECURSIVE_INITIALIZER_LOCK
 			recursiveSpinUnLock();
+		#else
+			_spin_unlock(&fInitializerLock);
+		#endif
 			throw;
 		}
 	}
 	
+#if RECURSIVE_INITIALIZER_LOCK
 	recursiveSpinUnLock();
+#else
+	_spin_unlock(&fInitializerLock);
+#endif
 }
 
 
@@ -1082,21 +889,16 @@
 		}
 	}
 	if ( partTime < sUnitsPerSecond ) {
-		uint32_t milliSecondsTimesHundred = (uint32_t)((partTime*100000)/sUnitsPerSecond);
-		uint32_t milliSeconds = (uint32_t)(milliSecondsTimesHundred/100);
-		uint32_t percentTimesTen = (uint32_t)((partTime*1000)/totalTime);
+		uint32_t milliSecondsTimeTen = (partTime*10000)/sUnitsPerSecond;
+		uint32_t milliSeconds = milliSecondsTimeTen/10;
+		uint32_t percentTimesTen = (partTime*1000)/totalTime;
 		uint32_t percent = percentTimesTen/10;
-		if ( milliSeconds >= 100 )
-			dyld::log("%s: %u.%02u milliseconds (%u.%u%%)\n", msg, milliSeconds, milliSecondsTimesHundred-milliSeconds*100, percent, percentTimesTen-percent*10);
-		else if ( milliSeconds >= 10 )
-			dyld::log("%s:  %u.%02u milliseconds (%u.%u%%)\n", msg, milliSeconds, milliSecondsTimesHundred-milliSeconds*100, percent, percentTimesTen-percent*10);
-		else
-			dyld::log("%s:   %u.%02u milliseconds (%u.%u%%)\n", msg, milliSeconds, milliSecondsTimesHundred-milliSeconds*100, percent, percentTimesTen-percent*10);
+		dyld::log("%s: %u.%u milliseconds (%u.%u%%)\n", msg, milliSeconds, milliSecondsTimeTen-milliSeconds*10, percent, percentTimesTen-percent*10);
 	}
 	else {
-		uint32_t secondsTimeTen = (uint32_t)((partTime*10)/sUnitsPerSecond);
+		uint32_t secondsTimeTen = (partTime*10)/sUnitsPerSecond;
 		uint32_t seconds = secondsTimeTen/10;
-		uint32_t percentTimesTen = (uint32_t)((partTime*1000)/totalTime);
+		uint32_t percentTimesTen = (partTime*1000)/totalTime;
 		uint32_t percent = percentTimesTen/10;
 		dyld::log("%s: %u.%u seconds (%u.%u%%)\n", msg, seconds, secondsTimeTen-seconds*10, percent, percentTimesTen-percent*10);
 	}
@@ -1124,45 +926,20 @@
 }
 
 
-void ImageLoader::printStatistics(unsigned int imageCount, const InitializerTimingList& timingInfo)
-{
-	uint64_t totalTime = fgTotalLoadLibrariesTime  + fgTotalRebaseTime + fgTotalBindTime + fgTotalWeakBindTime + fgTotalDOF + fgTotalInitTime;
-
-	uint64_t totalDyldTime = totalTime - fgTotalDebuggerPausedTime - fgTotalRebindCacheTime;
-	printTime("Total pre-main time", totalDyldTime, totalDyldTime);
-	printTime("         dylib loading time", fgTotalLoadLibrariesTime-fgTotalDebuggerPausedTime, totalDyldTime);
-	printTime("        rebase/binding time", fgTotalRebaseTime+fgTotalBindTime+fgTotalWeakBindTime-fgTotalRebindCacheTime, totalDyldTime);
-	printTime("            ObjC setup time", fgTotalObjCSetupTime, totalDyldTime);
-	printTime("           initializer time", fgTotalInitTime-fgTotalObjCSetupTime, totalDyldTime);
-	dyld::log("           slowest intializers :\n");
-	for (uintptr_t i=0; i < timingInfo.count; ++i) {
-		uint64_t t = timingInfo.images[i].initTime;
-		if ( t*50 < totalDyldTime )
-			continue;
-		dyld::log("%30s ", timingInfo.images[i].shortName);
-		if ( strncmp(timingInfo.images[i].shortName, "libSystem.", 10) == 0 )
-			t -= fgTotalObjCSetupTime;
-			printTime("", t, totalDyldTime);
-	}
-	dyld::log("\n");
-}
-
-void ImageLoader::printStatisticsDetails(unsigned int imageCount, const InitializerTimingList& timingInfo)
-{
-	uint64_t totalTime = fgTotalLoadLibrariesTime  + fgTotalRebaseTime + fgTotalBindTime + fgTotalWeakBindTime + fgTotalDOF + fgTotalInitTime;
+
+void ImageLoader::printStatistics(unsigned int imageCount)
+{
+	uint64_t totalTime = fgTotalLoadLibrariesTime + fgTotalRebaseTime + fgTotalBindTime + fgTotalInitTime;
 	char commaNum1[40];
 	char commaNum2[40];
 
-	printTime("  total time", totalTime, totalTime);
-	dyld::log("  total images loaded:  %d (%u from dyld shared cache)\n", imageCount, fgImagesUsedFromSharedCache);
-	dyld::log("  total segments mapped: %u, into %llu pages with %llu pages pre-fetched\n", fgTotalSegmentsMapped, fgTotalBytesMapped/4096, fgTotalBytesPreFetched/4096);
-	printTime("  total images loading time", fgTotalLoadLibrariesTime, totalTime);
-	printTime("  total load time in ObjC", fgTotalObjCSetupTime, totalTime);
-	printTime("  total debugger pause time", fgTotalDebuggerPausedTime, totalTime);
-	printTime("  total dtrace DOF registration time", fgTotalDOF, totalTime);
-	dyld::log("  total rebase fixups:  %s\n", commatize(fgTotalRebaseFixups, commaNum1));
-	printTime("  total rebase fixups time", fgTotalRebaseTime, totalTime);
-	dyld::log("  total binding fixups: %s\n", commatize(fgTotalBindFixups, commaNum1));
+	printTime("total time", totalTime, totalTime);
+	dyld::log("total images loaded:  %d (%u from dyld shared cache, %u needed no fixups)\n", imageCount, fgImagesUsedFromSharedCache, fgImagesRequiringNoFixups);
+	dyld::log("total segments mapped: %u, into %llu pages with %llu pages pre-fetched\n", fgTotalSegmentsMapped, fgTotalBytesMapped/4096, fgTotalBytesPreFetched/4096);
+	printTime("total images loading time", fgTotalLoadLibrariesTime, totalTime);
+	dyld::log("total rebase fixups:  %s\n", commatize(fgTotalRebaseFixups, commaNum1));
+	printTime("total rebase fixups time", fgTotalRebaseTime, totalTime);
+	dyld::log("total binding fixups: %s\n", commatize(fgTotalBindFixups, commaNum1));
 	if ( fgTotalBindSymbolsResolved != 0 ) {
 		uint32_t avgTimesTen = (fgTotalBindImageSearches * 10) / fgTotalBindSymbolsResolved;
 		uint32_t avgInt = fgTotalBindImageSearches / fgTotalBindSymbolsResolved;
@@ -1170,21 +947,9 @@
 		dyld::log("total binding symbol lookups: %s, average images searched per symbol: %u.%u\n", 
 				commatize(fgTotalBindSymbolsResolved, commaNum1), avgInt, avgTenths);
 	}
-	printTime("  total binding fixups time", fgTotalBindTime, totalTime);
-	printTime("  total weak binding fixups time", fgTotalWeakBindTime, totalTime);
-	printTime("  total redo shared cached bindings time", fgTotalRebindCacheTime, totalTime);
-	dyld::log("  total bindings lazily fixed up: %s of %s\n", commatize(fgTotalLazyBindFixups, commaNum1), commatize(fgTotalPossibleLazyBindFixups, commaNum2));
-	printTime("  total time in initializers and ObjC +load", fgTotalInitTime-fgTotalObjCSetupTime, totalTime);
-	for (uintptr_t i=0; i < timingInfo.count; ++i) {
-		uint64_t t = timingInfo.images[i].initTime;
-		if ( t*1000 < totalTime )
-			continue;
-		dyld::log("%42s ", timingInfo.images[i].shortName);
-		if ( strncmp(timingInfo.images[i].shortName, "libSystem.", 10) == 0 )
-			t -= fgTotalObjCSetupTime;
-		printTime("", t, totalTime);
-	}
-	
+	printTime("total binding fixups time", fgTotalBindTime, totalTime);
+	dyld::log("total bindings lazily fixed up: %s of %s\n", commatize(fgTotalLazyBindFixups, commaNum1), commatize(fgTotalPossibleLazyBindFixups, commaNum2));
+	printTime("total init time time", fgTotalInitTime, totalTime);
 }
 
 
@@ -1218,130 +983,129 @@
 }
 
 
-//
-// This function is the hotspot of symbol lookup.  It was pulled out of findExportedSymbol()
-// to enable it to be re-written in assembler if needed.
-//
-const uint8_t* ImageLoader::trieWalk(const uint8_t* start, const uint8_t* end, const char* s)
-{
-	//dyld::log("trieWalk(%p, %p, %s)\n", start, end, s);
-	++fgSymbolTrieSearchs;
-	const uint8_t* p = start;
-	while ( p != NULL ) {
-		uintptr_t terminalSize = *p++;
-		if ( terminalSize > 127 ) {
-			// except for re-export-with-rename, all terminal sizes fit in one byte
-			--p;
-			terminalSize = read_uleb128(p, end);
-		}
-		if ( (*s == '\0') && (terminalSize != 0) ) {
-			//dyld::log("trieWalk(%p) returning %p\n", start, p);
-			return p;
-		}
-		const uint8_t* children = p + terminalSize;
-		if ( children > end ) {
-			dyld::log("trieWalk() malformed trie node, terminalSize=0x%lx extends past end of trie\n", terminalSize);
-			return NULL;
-		}
-		//dyld::log("trieWalk(%p) sym=%s, terminalSize=%lu, children=%p\n", start, s, terminalSize, children);
-		uint8_t childrenRemaining = *children++;
-		p = children;
-		uintptr_t nodeOffset = 0;
-		for (; childrenRemaining > 0; --childrenRemaining) {
-			const char* ss = s;
-			//dyld::log("trieWalk(%p) child str=%s\n", start, (char*)p);
-			bool wrongEdge = false;
-			// scan whole edge to get to next edge
-			// if edge is longer than target symbol name, don't read past end of symbol name
-			char c = *p;
-			while ( c != '\0' ) {
-				if ( !wrongEdge ) {
-					if ( c != *ss )
-						wrongEdge = true;
-					++ss;
-				}
-				++p;
-				c = *p;
-			}
-			if ( wrongEdge ) {
-				// advance to next child
-				++p; // skip over zero terminator
-				// skip over uleb128 until last byte is found
-				while ( (*p & 0x80) != 0 )
-					++p;
-				++p; // skip over last byte of uleb128
-				if ( p > end ) {
-					dyld::log("trieWalk() malformed trie node, child node extends past end of trie\n");
-					return NULL;
-				}
-			}
-			else {
- 				// the symbol so far matches this edge (child)
-				// so advance to the child's node
-				++p;
-				nodeOffset = read_uleb128(p, end);
-				if ( (nodeOffset == 0) || ( &start[nodeOffset] > end) ) {
-					dyld::log("trieWalk() malformed trie child, nodeOffset=0x%lx out of range\n", nodeOffset);
-					return NULL;
-				}
-				s = ss;
-				//dyld::log("trieWalk() found matching edge advancing to node 0x%lx\n", nodeOffset);
-				break;
-			}
-		}
-		if ( nodeOffset != 0 )
-			p = &start[nodeOffset];
-		else
-			p = NULL;
-	}
-	//dyld::log("trieWalk(%p) return NULL\n", start);
-	return NULL;
-}
-
-
-	
-uintptr_t ImageLoader::read_uleb128(const uint8_t*& p, const uint8_t* end)
-{
-	uint64_t result = 0;
-	int		 bit = 0;
-	do {
-		if (p == end)
-			dyld::throwf("malformed uleb128");
-
-		uint64_t slice = *p & 0x7f;
-
-		if (bit > 63)
-			dyld::throwf("uleb128 too big for uint64, bit=%d, result=0x%0llX", bit, result);
-		else {
-			result |= (slice << bit);
-			bit += 7;
-		}
-	} while (*p++ & 0x80);
-	return result;
-}
-
-
-intptr_t ImageLoader::read_sleb128(const uint8_t*& p, const uint8_t* end)
-{
-	int64_t result = 0;
-	int bit = 0;
-	uint8_t byte;
-	do {
-		if (p == end)
-			throw "malformed sleb128";
-		byte = *p++;
-		result |= (((int64_t)(byte & 0x7f)) << bit);
-		bit += 7;
-	} while (byte & 0x80);
-	// sign extend negative numbers
-	if ( (byte & 0x40) != 0 )
-		result |= (-1LL) << bit;
-	return result;
-}
-
-
-VECTOR_NEVER_DESTRUCTED_IMPL(ImageLoader::InterposeTuple);
-VECTOR_NEVER_DESTRUCTED_IMPL(ImagePair);
-
-
-
+void Segment::map(int fd, uint64_t offsetInFatWrapper, intptr_t slide, const ImageLoader* image, const ImageLoader::LinkContext& context)
+{
+	vm_offset_t fileOffset = this->getFileOffset() + offsetInFatWrapper;
+	vm_size_t size = this->getFileSize();
+	void* requestedLoadAddress = (void*)(this->getPreferredLoadAddress() + slide);
+	int protection = 0;
+	if ( !this->unaccessible() ) {
+		if ( this->executable() )
+			protection   |= PROT_EXEC;
+		if ( this->readable() )
+			protection   |= PROT_READ;
+		if ( this->writeable() )
+			protection   |= PROT_WRITE;
+	}
+#if __i386__
+	// initially map __IMPORT segments R/W so dyld can update them
+	if ( this->readOnlyImportStubs() )
+		protection |= PROT_WRITE;
+#endif
+	// wholly zero-fill segments have nothing to mmap() in
+	if ( size > 0 ) {
+		void* loadAddress = mmap(requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
+		if ( loadAddress == ((void*)(-1)) )
+			dyld::throwf("mmap() error %d at address=0x%08lX, size=0x%08lX segment=%s in Segment::map() mapping %s", errno, (uintptr_t)requestedLoadAddress, (uintptr_t)size, this->getName(), image->getPath());
+	}
+	// update stats
+	++ImageLoader::fgTotalSegmentsMapped;
+	ImageLoader::fgTotalBytesMapped += size;
+	if ( context.verboseMapping )
+		dyld::log("%18s at %p->%p with permissions %c%c%c\n", this->getName(), requestedLoadAddress, (char*)requestedLoadAddress+this->getFileSize()-1,
+			(protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
+}
+
+void Segment::map(const void* memoryImage, intptr_t slide, const ImageLoader* image, const ImageLoader::LinkContext& context)
+{
+	vm_address_t loadAddress = this->getPreferredLoadAddress() + slide;
+	vm_address_t srcAddr = (uintptr_t)memoryImage + this->getFileOffset();
+	vm_size_t size = this->getFileSize();
+	kern_return_t r = vm_copy(mach_task_self(), srcAddr, size, loadAddress);
+	if ( r != KERN_SUCCESS ) 
+		throw "can't map segment";
+		
+	if ( context.verboseMapping )
+		dyld::log("%18s at %p->%p\n", this->getName(), (char*)loadAddress, (char*)loadAddress+this->getFileSize()-1);
+}
+
+void Segment::setPermissions(const ImageLoader::LinkContext& context, const ImageLoader* image)
+{
+	vm_prot_t protection = 0;
+	if ( !this->unaccessible() ) {
+		if ( this->executable() )
+			protection   |= VM_PROT_EXECUTE;
+		if ( this->readable() )
+			protection   |= VM_PROT_READ;
+		if ( this->writeable() )
+			protection   |= VM_PROT_WRITE;
+	}
+	vm_address_t addr = this->getActualLoadAddress(image);
+	vm_size_t size = this->getSize();
+	const bool setCurrentPermissions = false;
+	kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
+	if ( r != KERN_SUCCESS ) 
+		throw "can't set vm permissions for mapped segment";
+	if ( context.verboseMapping ) {
+		dyld::log("%18s at %p->%p altered permissions to %c%c%c\n", this->getName(), (char*)addr, (char*)addr+this->getFileSize()-1,
+			(protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
+	}
+}	
+
+void Segment::tempWritable(const ImageLoader::LinkContext& context, const ImageLoader* image)
+{
+	vm_address_t addr = this->getActualLoadAddress(image);
+	vm_size_t size = this->getSize();
+	const bool setCurrentPermissions = false;
+	vm_prot_t protection = VM_PROT_WRITE | VM_PROT_READ;
+	if ( this->executable() )
+		protection |= VM_PROT_EXECUTE;
+	kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
+	if ( r != KERN_SUCCESS ) 
+		throw "can't set vm permissions for mapped segment";
+	if ( context.verboseMapping ) {
+		dyld::log("%18s at %p->%p altered permissions to %c%c%c\n", this->getName(), (char*)addr, (char*)addr+this->getFileSize()-1,
+			(protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
+	}
+}
+
+
+bool Segment::hasTrailingZeroFill()
+{
+	return ( this->writeable() && (this->getSize() > this->getFileSize()) );
+}
+
+
+uintptr_t Segment::reserveAnAddressRange(size_t length, const ImageLoader::LinkContext& context)
+{
+	vm_address_t addr = 0;
+	vm_size_t size = length;
+	// in PIE programs, load initial dylibs after main executable so they don't have fixed addresses either
+	if ( fgNextPIEDylibAddress != 0 ) {
+		addr = fgNextPIEDylibAddress + (arc4random() & 0x3) * 4096; // add small random padding between dylibs
+		kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_FIXED);
+		if ( r == KERN_SUCCESS ) {
+			fgNextPIEDylibAddress = addr + size;
+			return addr;
+		}
+		fgNextPIEDylibAddress = 0;
+	}
+	kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_ANYWHERE);
+	if ( r != KERN_SUCCESS ) 
+		throw "out of address space";
+	
+	return addr;
+}
+
+bool Segment::reserveAddressRange(uintptr_t start, size_t length)
+{
+	vm_address_t addr = start;
+	vm_size_t size = length;
+	kern_return_t r = vm_allocate(mach_task_self(), &addr, size, false /*only this range*/);
+	if ( r != KERN_SUCCESS ) 
+		return false;
+	return true;
+}
+
+
+