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src/dyld.cpp dyld-45.3 dyld-210.2.3
--- dyld/dyld-45.3/src/dyld.cpp
+++ dyld/dyld-210.2.3/src/dyld.cpp
@@ -1,6 +1,6 @@
 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
  *
- * Copyright (c) 2004-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2010 Apple Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
@@ -25,42 +25,105 @@
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>
+#include <errno.h>
 #include <fcntl.h>
+#include <dirent.h>
 #include <sys/param.h>
 #include <mach/mach_time.h> // mach_absolute_time()
 #include <sys/types.h>
 #include <sys/stat.h> 
+#include <sys/syscall.h>
 #include <mach-o/fat.h> 
 #include <mach-o/loader.h> 
+#include <mach-o/ldsyms.h> 
 #include <libkern/OSByteOrder.h> 
+#include <libkern/OSAtomic.h>
 #include <mach/mach.h>
 #include <sys/sysctl.h>
+#include <sys/mman.h>
+#include <sys/dtrace.h>
+#include <libkern/OSAtomic.h>
+#include <Availability.h>
+#include <Kernel/sys/codesign.h>
+
+
+#ifndef CPU_SUBTYPE_ARM_V5TEJ
+	#define CPU_SUBTYPE_ARM_V5TEJ		((cpu_subtype_t) 7)
+#endif
+#ifndef CPU_SUBTYPE_ARM_XSCALE
+	#define CPU_SUBTYPE_ARM_XSCALE		((cpu_subtype_t) 8)
+#endif
+#ifndef CPU_SUBTYPE_ARM_V7
+	#define CPU_SUBTYPE_ARM_V7			((cpu_subtype_t) 9)
+#endif
+#ifndef CPU_SUBTYPE_ARM_V7F
+	#define CPU_SUBTYPE_ARM_V7F			((cpu_subtype_t) 10)
+#endif
+#ifndef CPU_SUBTYPE_ARM_V7S
+	#define CPU_SUBTYPE_ARM_V7S			((cpu_subtype_t) 11)
+#endif
+#ifndef CPU_SUBTYPE_ARM_V7K
+	#define CPU_SUBTYPE_ARM_V7K			((cpu_subtype_t) 12)
+#endif
+#ifndef LC_DYLD_ENVIRONMENT
+	#define LC_DYLD_ENVIRONMENT			0x27
+#endif
+
+#ifndef VM_PROT_SLIDE   
+    #define VM_PROT_SLIDE 0x20
+#endif
 
 #include <vector>
+#include <algorithm>
 
 #include "mach-o/dyld_gdb.h"
 
 #include "dyld.h"
 #include "ImageLoader.h"
 #include "ImageLoaderMachO.h"
-#include "dyldLibSystemThreadHelpers.h"
+#include "dyldLibSystemInterface.h"
+#if DYLD_SHARED_CACHE_SUPPORT
+#include "dyld_cache_format.h"
+#endif
+#if CORESYMBOLICATION_SUPPORT
+#include "coreSymbolicationDyldSupport.hpp"
+#endif
+
+// from _simple.h in libc
+typedef struct _SIMPLE*		_SIMPLE_STRING;
+extern "C" void				_simple_vdprintf(int __fd, const char *__fmt, va_list __ap);
+extern "C" void				_simple_dprintf(int __fd, const char *__fmt, ...);
+extern "C" _SIMPLE_STRING	_simple_salloc(void);
+extern "C" int				_simple_vsprintf(_SIMPLE_STRING __b, const char *__fmt, va_list __ap);
+extern "C" void				_simple_sfree(_SIMPLE_STRING __b);
+extern "C" char *			_simple_string(_SIMPLE_STRING __b);
+
+
+
+// ARM is the only architecture that use cpu-sub-types
+#define CPU_SUBTYPES_SUPPORTED  __arm__
+
 
 
 #define CPU_TYPE_MASK 0x00FFFFFF	/* complement of CPU_ARCH_MASK */
 
 
 /* implemented in dyld_gdb.cpp */
-void addImagesToAllImages(uint32_t infoCount, const dyld_image_info info[]);
-void removeImageFromAllImages(const mach_header* mh);
-#if OLD_GDB_DYLD_INTERFACE
-void addImageForgdb(const mach_header* mh, uintptr_t slide, const char* physicalPath, const char* logicalPath);
-void removeImageForgdb(const struct mach_header* mh);
-#endif
+extern void addImagesToAllImages(uint32_t infoCount, const dyld_image_info info[]);
+extern void removeImageFromAllImages(const mach_header* mh);
+extern void setAlImageInfosHalt(const char* message, uintptr_t flags);
+extern void addNonSharedCacheImageUUID(const dyld_uuid_info& info);
+extern const char* notifyGDB(enum dyld_image_states state, uint32_t infoCount, const dyld_image_info info[]);
 
 // magic so CrashReporter logs message
 extern "C" {
 	char error_string[1024];
 }
+// implemented in dyldStartup.s for CrashReporter
+extern "C" void dyld_fatal_error(const char* errString) __attribute__((noreturn));
+
+// magic linker symbol for start of dyld binary
+extern "C" void* __dso_handle;
 
 
 //
@@ -84,15 +147,21 @@
 	const char* const *			DYLD_FALLBACK_FRAMEWORK_PATH;
 	const char* const *			DYLD_LIBRARY_PATH;
 	const char* const *			DYLD_FALLBACK_LIBRARY_PATH;
-	const char*	const *			DYLD_ROOT_PATH;
 	const char* const *			DYLD_INSERT_LIBRARIES;
 	const char* const *			LD_LIBRARY_PATH;			// for unix conformance
+	const char* const *			DYLD_VERSIONED_LIBRARY_PATH;
+	const char* const *			DYLD_VERSIONED_FRAMEWORK_PATH;
 	bool						DYLD_PRINT_LIBRARIES;
 	bool						DYLD_PRINT_LIBRARIES_POST_LAUNCH;
 	bool						DYLD_BIND_AT_LAUNCH;
 	bool						DYLD_PRINT_STATISTICS;
 	bool						DYLD_PRINT_OPTS;
 	bool						DYLD_PRINT_ENV;
+	bool						DYLD_DISABLE_DOFS;
+	bool						DYLD_PRINT_CS_NOTIFICATIONS;
+                            //  DYLD_SHARED_CACHE_DONT_VALIDATE ==> sSharedCacheIgnoreInodeAndTimeStamp
+                            //  DYLD_SHARED_CACHE_DIR           ==> sSharedCacheDir
+							//	DYLD_ROOT_PATH					==> gLinkContext.rootPaths
 							//	DYLD_IMAGE_SUFFIX				==> gLinkContext.imageSuffix
 							//	DYLD_PRINT_OPTS					==> gLinkContext.verboseOpts
 							//	DYLD_PRINT_ENV					==> gLinkContext.verboseEnv
@@ -100,39 +169,255 @@
 							//	DYLD_PRINT_INITIALIZERS			==> gLinkContext.verboseInit
 							//	DYLD_PRINT_SEGMENTS				==> gLinkContext.verboseMapping
 							//	DYLD_PRINT_BINDINGS				==> gLinkContext.verboseBind
+							//  DYLD_PRINT_WEAK_BINDINGS		==> gLinkContext.verboseWeakBind
 							//	DYLD_PRINT_REBASINGS			==> gLinkContext.verboseRebase
+							//	DYLD_PRINT_DOFS					==> gLinkContext.verboseDOF
 							//	DYLD_PRINT_APIS					==> gLogAPIs
 							//	DYLD_IGNORE_PREBINDING			==> gLinkContext.prebindUsage
 							//	DYLD_PREBIND_DEBUG				==> gLinkContext.verbosePrebinding
 							//	DYLD_NEW_LOCAL_SHARED_REGIONS	==> gLinkContext.sharedRegionMode
 							//	DYLD_SHARED_REGION				==> gLinkContext.sharedRegionMode
-							//	DYLD_SLIDE_AND_PACK_DYLIBS		==> gLinkContext.slideAndPackDylibs
 							//	DYLD_PRINT_WARNINGS				==> gLinkContext.verboseWarnings
+							//	DYLD_PRINT_RPATHS				==> gLinkContext.verboseRPaths
+							//	DYLD_PRINT_INTERPOSING			==> gLinkContext.verboseInterposing
 };
-
+        
+typedef std::vector<dyld_image_state_change_handler> StateHandlers;
+struct RegisteredDOF { const mach_header* mh; int registrationID; };
+struct DylibOverride { const char* installName; const char* override; };
+
+enum RestrictedReason { restrictedNot, restrictedBySetGUid, restrictedBySegment, restrictedByEntitlements };
+	
 // all global state
 static const char*					sExecPath = NULL;
-static const struct mach_header*	sMainExecutableMachHeader = NULL;
+static const macho_header*			sMainExecutableMachHeader = NULL;
+#if CPU_SUBTYPES_SUPPORTED
 static cpu_type_t					sHostCPU;
 static cpu_subtype_t				sHostCPUsubtype;
+#endif
 static ImageLoader*					sMainExecutable = NULL;
-static bool							sAllImagesMightContainUnlinkedImages;	 // necessary until will support dylib unloading
+static bool							sProcessIsRestricted = false;
+static RestrictedReason			sRestrictedReason = restrictedNot;
+static unsigned int					sInsertedDylibCount = 0;
 static std::vector<ImageLoader*>	sAllImages;
 static std::vector<ImageLoader*>	sImageRoots;
 static std::vector<ImageLoader*>	sImageFilesNeedingTermination;
-static std::vector<ImageLoader*>	sImagesToNotifyAboutOtherImages;
+static std::vector<RegisteredDOF>	sImageFilesNeedingDOFUnregistration;
 static std::vector<ImageCallback>   sAddImageCallbacks;
 static std::vector<ImageCallback>   sRemoveImageCallbacks;
+static StateHandlers				sSingleHandlers[7];
+static StateHandlers				sBatchHandlers[7];
 static ImageLoader*					sLastImageByAddressCache;
 static EnvironmentVariables			sEnv;
 static const char*					sFrameworkFallbackPaths[] = { "$HOME/Library/Frameworks", "/Library/Frameworks", "/Network/Library/Frameworks", "/System/Library/Frameworks", NULL };
 static const char*					sLibraryFallbackPaths[] = { "$HOME/lib", "/usr/local/lib", "/usr/lib", NULL };
-static BundleNotificationCallBack   sBundleNotifier = NULL;
-static BundleLocatorCallBack		sBundleLocation = NULL;
 static UndefinedHandler				sUndefinedHandler = NULL;
+static ImageLoader*					sBundleBeingLoaded = NULL;	// hack until OFI is reworked
+#if DYLD_SHARED_CACHE_SUPPORT
+static const dyld_cache_header*		sSharedCache = NULL;
+static long							sSharedCacheSlide = 0;
+static bool							sSharedCacheIgnoreInodeAndTimeStamp = false;
+#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+	bool							gSharedCacheOverridden = false;
+	static const char*				sSharedCacheDir = IPHONE_DYLD_SHARED_CACHE_DIR;
+	static bool						sDylibsOverrideCache = false;
+#else
+	static const char*				sSharedCacheDir = MACOSX_DYLD_SHARED_CACHE_DIR;
+#endif
+#endif
 ImageLoader::LinkContext			gLinkContext;
 bool								gLogAPIs = false;
-const struct ThreadingHelpers*		gThreadHelpers = NULL;
+const struct LibSystemHelpers*		gLibSystemHelpers = NULL;
+#if SUPPORT_OLD_CRT_INITIALIZATION
+bool								gRunInitializersOldWay = false;
+#endif
+static std::vector<DylibOverride>	sDylibOverrides;
+
+//
+// The MappedRanges structure is used for fast address->image lookups.
+// The table is only updated when the dyld lock is held, so we don't
+// need to worry about multiple writers.  But readers may look at this
+// data without holding the lock. Therefore, all updates must be done
+// in an order that will never cause readers to see inconsistent data.
+// The general rule is that if the image field is non-NULL then
+// the other fields are valid.
+//
+struct MappedRanges
+{
+	enum { count=400 };
+	struct {
+		ImageLoader*	image;
+		uintptr_t		start;
+		uintptr_t		end;
+	} array[count];
+	MappedRanges*		next;
+};
+
+static MappedRanges			sMappedRangesStart;
+
+void addMappedRange(ImageLoader* image, uintptr_t start, uintptr_t end)
+{
+	//dyld::log("addMappedRange(0x%lX->0x%lX) for %s\n", start, end, image->getShortName());
+	for (MappedRanges* p = &sMappedRangesStart; p != NULL; p = p->next) {
+		for (int i=0; i < MappedRanges::count; ++i) {
+			if ( p->array[i].image == NULL ) {
+				p->array[i].start = start;
+				p->array[i].end = end;
+				// add image field last with a barrier so that any reader will see consistent records
+				OSMemoryBarrier();
+				p->array[i].image = image;
+				return;
+			}
+		}
+	}
+	// table must be full, chain another
+	MappedRanges* newRanges = (MappedRanges*)malloc(sizeof(MappedRanges));
+	bzero(newRanges, sizeof(MappedRanges));
+	newRanges->array[0].start = start;
+	newRanges->array[0].end = end;
+	newRanges->array[0].image = image;
+	for (MappedRanges* p = &sMappedRangesStart; p != NULL; p = p->next) {
+		if ( p->next == NULL ) {
+			OSMemoryBarrier();
+			p->next = newRanges;
+			break;
+		}
+	}
+}
+
+void removedMappedRanges(ImageLoader* image)
+{
+	for (MappedRanges* p = &sMappedRangesStart; p != NULL; p = p->next) {
+		for (int i=0; i < MappedRanges::count; ++i) {
+			if ( p->array[i].image == image ) {
+				// clear with a barrier so that any reader will see consistent records
+				OSMemoryBarrier();
+				p->array[i].image = NULL;
+			}
+		}
+	}
+}
+
+ImageLoader* findMappedRange(uintptr_t target)
+{
+	for (MappedRanges* p = &sMappedRangesStart; p != NULL; p = p->next) {
+		for (int i=0; i < MappedRanges::count; ++i) {
+			if ( p->array[i].image != NULL ) {
+				if ( (p->array[i].start <= target) && (target < p->array[i].end) )
+					return p->array[i].image;
+			}
+		}
+	}
+	return NULL;
+}
+
+
+
+const char* mkstringf(const char* format, ...)
+{
+	_SIMPLE_STRING buf = _simple_salloc();
+	if ( buf != NULL ) {
+		va_list	list;
+		va_start(list, format);
+		_simple_vsprintf(buf, format, list);
+		va_end(list);
+		const char*	t = strdup(_simple_string(buf));
+		_simple_sfree(buf);
+		if ( t != NULL )
+			return t;
+	}
+	return "mkstringf, out of memory error";
+}
+
+
+void throwf(const char* format, ...) 
+{
+	_SIMPLE_STRING buf = _simple_salloc();
+	if ( buf != NULL ) {
+		va_list	list;
+		va_start(list, format);
+		_simple_vsprintf(buf, format, list);
+		va_end(list);
+		const char*	t = strdup(_simple_string(buf));
+		_simple_sfree(buf);
+		if ( t != NULL )
+			throw t;
+	}
+	throw "throwf, out of memory error";
+}
+
+
+//#define ALTERNATIVE_LOGFILE "/dev/console"
+
+static int sLogfile = STDERR_FILENO;
+
+#if LOG_BINDINGS
+static int sBindingsLogfile = -1;
+static void mysprintf(char* dst, const char* format, ...)
+{
+	_SIMPLE_STRING buf = _simple_salloc();
+	if ( buf != NULL ) {
+		va_list	list;
+		va_start(list, format);
+		_simple_vsprintf(buf, format, list);
+		va_end(list);
+		strcpy(dst, _simple_string(buf));
+		_simple_sfree(buf);
+	}
+	else {
+		strcpy(dst, "out of memory");
+	}
+}
+void logBindings(const char* format, ...) 
+{
+	if ( sBindingsLogfile != -1 ) {
+		va_list	list;
+		va_start(list, format);
+		_simple_vdprintf(sBindingsLogfile, format, list);
+		va_end(list);
+	}
+}
+
+#endif
+
+void log(const char* format, ...) 
+{
+	va_list	list;
+	va_start(list, format);
+	_simple_vdprintf(sLogfile, format, list);
+	va_end(list);
+}
+
+void warn(const char* format, ...) 
+{
+	_simple_dprintf(sLogfile, "dyld: warning, ");
+	va_list	list;
+	va_start(list, format);
+	_simple_vdprintf(sLogfile, format, list);
+	va_end(list);
+}
+
+
+// <rdar://problem/8867781> control access to sAllImages through a lock 
+// because global dyld lock is not held during initialization phase of dlopen()
+static long sAllImagesLock = 0;
+
+static void allImagesLock()
+{
+    //dyld::log("allImagesLock()\n");
+	while ( ! OSAtomicCompareAndSwapPtrBarrier((void*)0, (void*)1, (void**)&sAllImagesLock) ) {
+        // spin
+    }
+}
+
+static void allImagesUnlock()
+{
+    //dyld::log("allImagesUnlock()\n");
+	while ( ! OSAtomicCompareAndSwapPtrBarrier((void*)1, (void*)0, (void**)&sAllImagesLock) ) {
+        // spin
+   }
+}
+
 
 
 
@@ -147,60 +432,317 @@
 };
 
 FileOpener::FileOpener(const char* path)
+ : fd(-1)
 {
 	fd = open(path, O_RDONLY, 0);
 }
 
 FileOpener::~FileOpener()
 {
-	close(fd);
-}
-
-
-
-// Objective-C installs an addImage hook to dyld to get notified about new images
-// The callback needs to be run after the image is rebased and bound, but before its initializers are called
-static uint32_t imageNotification(ImageLoader* image, uint32_t startIndex)
-{
-	// tell all register add image handlers about this
-	const uint32_t callbackCount = sAddImageCallbacks.size();
-	for (uint32_t i=startIndex; i < callbackCount; ++i) {
-		ImageCallback cb = sAddImageCallbacks[i];
-		//fprintf(stderr, "dyld: calling add-image-callback[%d]=%p for %s\n", i, cb, image->getPath());
-		(cb)(image->machHeader(), image->getSlide());
-	}
-	return callbackCount;
-}
-
-
-
-// notify gdb et al about these new images
-static void notifyAdding(std::vector<ImageLoader*>& images)
-{
-	// build array
-	unsigned int len = images.size();
-	if ( len != 0 ) {
-		dyld_image_info	infos[len];
-		for (unsigned int i=0; i < len; ++i) {
-			dyld_image_info* p = &infos[i];
-			ImageLoader* image = images[i];
-			p->imageLoadAddress = image->machHeader();
-			p->imageFilePath = image->getPath();
-			p->imageFileModDate = image->lastModified();
-			//fprintf(stderr, "notifying objc about %s\n", image->getPath());
-		}
-		
-		// tell gdb
-		addImagesToAllImages(len, infos);
-				
-		// tell all interested images (after gdb, so you can debug anything the notification does)
-		for (std::vector<ImageLoader*>::iterator it=sImagesToNotifyAboutOtherImages.begin(); it != sImagesToNotifyAboutOtherImages.end(); it++) {
-			(*it)->doNotification(dyld_image_adding, len, infos);
-		}
-	}
-}
-
-
+	if ( fd != -1 )
+		close(fd);
+}
+
+
+static void	registerDOFs(const std::vector<ImageLoader::DOFInfo>& dofs)
+{
+	const unsigned int dofSectionCount = dofs.size();
+	if ( !sEnv.DYLD_DISABLE_DOFS && (dofSectionCount != 0) ) {
+		int fd = open("/dev/" DTRACEMNR_HELPER, O_RDWR);
+		if ( fd < 0 ) {
+			//dyld::warn("can't open /dev/" DTRACEMNR_HELPER " to register dtrace DOF sections\n");
+		}
+		else {
+			// allocate a buffer on the stack for the variable length dof_ioctl_data_t type
+			uint8_t buffer[sizeof(dof_ioctl_data_t) + dofSectionCount*sizeof(dof_helper_t)];
+			dof_ioctl_data_t* ioctlData = (dof_ioctl_data_t*)buffer;
+			
+			// fill in buffer with one dof_helper_t per DOF section
+			ioctlData->dofiod_count = dofSectionCount;
+			for (unsigned int i=0; i < dofSectionCount; ++i) {
+				strlcpy(ioctlData->dofiod_helpers[i].dofhp_mod, dofs[i].imageShortName, DTRACE_MODNAMELEN);
+				ioctlData->dofiod_helpers[i].dofhp_dof = (uintptr_t)(dofs[i].dof);
+				ioctlData->dofiod_helpers[i].dofhp_addr = (uintptr_t)(dofs[i].dof);
+			}
+			
+			// tell kernel about all DOF sections en mas
+			// pass pointer to ioctlData because ioctl() only copies a fixed size amount of data into kernel
+			user_addr_t val = (user_addr_t)(unsigned long)ioctlData;
+			if ( ioctl(fd, DTRACEHIOC_ADDDOF, &val) != -1 ) {
+				// kernel returns a unique identifier for each section in the dofiod_helpers[].dofhp_dof field.
+				for (unsigned int i=0; i < dofSectionCount; ++i) {
+					RegisteredDOF info;
+					info.mh = dofs[i].imageHeader;
+					info.registrationID = (int)(ioctlData->dofiod_helpers[i].dofhp_dof);
+					sImageFilesNeedingDOFUnregistration.push_back(info);
+					if ( gLinkContext.verboseDOF ) {
+						dyld::log("dyld: registering DOF section 0x%p in %s with dtrace, ID=0x%08X\n", 
+							dofs[i].dof, dofs[i].imageShortName, info.registrationID);
+					}
+				}
+			}
+			else {
+				dyld::log( "dyld: ioctl to register dtrace DOF section failed\n");
+			}
+			close(fd);
+		}
+	}
+}
+
+static void	unregisterDOF(int registrationID)
+{
+	int fd = open("/dev/" DTRACEMNR_HELPER, O_RDWR);
+	if ( fd < 0 ) {
+		dyld::warn("can't open /dev/" DTRACEMNR_HELPER " to unregister dtrace DOF section\n");
+	}
+	else {
+		ioctl(fd, DTRACEHIOC_REMOVE, registrationID);
+		close(fd);
+		if ( gLinkContext.verboseInit )
+			dyld::warn("unregistering DOF section ID=0x%08X with dtrace\n", registrationID);
+	}
+}
+
+
+//
+// _dyld_register_func_for_add_image() is implemented as part of the general image state change notification
+//
+static void notifyAddImageCallbacks(ImageLoader* image)
+{
+	// use guard so that we cannot notify about the same image twice
+	if ( ! image->addFuncNotified() ) {
+		for (std::vector<ImageCallback>::iterator it=sAddImageCallbacks.begin(); it != sAddImageCallbacks.end(); it++)
+			(*it)(image->machHeader(), image->getSlide());
+		image->setAddFuncNotified();
+	}
+}
+
+
+
+// notify gdb about these new images
+static const char* updateAllImages(enum dyld_image_states state, uint32_t infoCount, const struct dyld_image_info info[])
+{
+	// <rdar://problem/8812589> don't add images without paths to all-image-info-list
+	if ( info[0].imageFilePath != NULL )
+		addImagesToAllImages(infoCount, info);
+	return NULL;
+}
+
+
+static StateHandlers* stateToHandlers(dyld_image_states state, StateHandlers handlersArray[8]) 
+{
+	switch ( state ) {
+		case dyld_image_state_mapped:
+			return &handlersArray[0];
+			
+		case dyld_image_state_dependents_mapped:
+			return &handlersArray[1];
+			
+		case dyld_image_state_rebased:
+			return &handlersArray[2];
+			
+		case dyld_image_state_bound:
+			return &handlersArray[3];
+			
+		case dyld_image_state_dependents_initialized:
+			return &handlersArray[4];
+
+		case dyld_image_state_initialized:
+			return &handlersArray[5];
+			
+		case dyld_image_state_terminated:
+			return &handlersArray[6];
+	}
+	return NULL;
+}
+
+
+static void notifySingle(dyld_image_states state, const ImageLoader* image)
+{
+	//dyld::log("notifySingle(state=%d, image=%s)\n", state, image->getPath());
+	std::vector<dyld_image_state_change_handler>* handlers = stateToHandlers(state, sSingleHandlers);
+	if ( handlers != NULL ) {
+		dyld_image_info info;
+		info.imageLoadAddress	= image->machHeader();
+		info.imageFilePath		= image->getRealPath();
+		info.imageFileModDate	= image->lastModified();
+		for (std::vector<dyld_image_state_change_handler>::iterator it = handlers->begin(); it != handlers->end(); ++it) {
+			const char* result = (*it)(state, 1, &info);
+			if ( (result != NULL) && (state == dyld_image_state_mapped) ) {
+				//fprintf(stderr, "  image rejected by handler=%p\n", *it);
+				// make copy of thrown string so that later catch clauses can free it
+				const char* str = strdup(result);
+				throw str;
+			}
+		}
+	}
+	if ( state == dyld_image_state_mapped ) {
+		// <rdar://problem/7008875> Save load addr + UUID for images from outside the shared cache
+		if ( !image->inSharedCache() ) {
+			dyld_uuid_info info;
+			if ( image->getUUID(info.imageUUID) ) {
+				info.imageLoadAddress = image->machHeader();
+				addNonSharedCacheImageUUID(info);
+			}
+		}
+	}
+#if CORESYMBOLICATION_SUPPORT
+    // mach message csdlc about dynamically loaded images 
+	if ( image->addFuncNotified() && (state == dyld_image_state_terminated) ) {
+		if ( sEnv.DYLD_PRINT_CS_NOTIFICATIONS ) {
+			dyld::log("dyld core symbolication unload notification: %p %s\n", image->machHeader(), image->getPath());
+		}
+		if ( dyld_all_image_infos.coreSymbolicationShmPage != NULL) {
+			CSCppDyldSharedMemoryPage* connection = (CSCppDyldSharedMemoryPage*)dyld_all_image_infos.coreSymbolicationShmPage;
+			if ( connection->is_valid_version() ) {
+				coresymbolication_unload_image(connection, image);
+			}
+		}
+	}
+#endif
+}
+
+
+
+
+//
+// Normally, dyld_all_image_infos is only updated in batches after an entire
+// graph is loaded.  But if there is an error loading the initial set of
+// dylibs needed by the main executable, dyld_all_image_infos is not yet set 
+// up, leading to usually brief crash logs.
+//
+// This function manually adds the images loaded so far to dyld_all_image_infos.
+// It should only be called before terminating.
+//
+void syncAllImages()
+{
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); ++it) {
+		dyld_image_info info;
+		ImageLoader* image = *it;
+		info.imageLoadAddress = image->machHeader();
+		info.imageFilePath = image->getRealPath();
+		info.imageFileModDate = image->lastModified();
+		// add to all_image_infos if not already there
+		bool found = false;
+		int existingCount = dyld_all_image_infos.infoArrayCount;
+		const dyld_image_info* existing = dyld_all_image_infos.infoArray;
+		if ( existing != NULL ) {
+			for (int i=0; i < existingCount; ++i) {
+				if ( existing[i].imageLoadAddress == info.imageLoadAddress ) {
+					//dyld::log("not adding %s\n", info.imageFilePath);
+					found = true;
+					break;
+				}
+			}
+		}
+		if ( ! found ) {
+			//dyld::log("adding %s\n", info.imageFilePath);
+			addImagesToAllImages(1, &info);
+		}
+	}
+}
+
+
+static int imageSorter(const void* l, const void* r)
+{
+	const ImageLoader* left = *((ImageLoader**)l);
+	const ImageLoader* right= *((ImageLoader**)r);
+	return left->compare(right);
+}
+
+static void notifyBatchPartial(dyld_image_states state, bool orLater, dyld_image_state_change_handler onlyHandler)
+{
+	std::vector<dyld_image_state_change_handler>* handlers = stateToHandlers(state, sBatchHandlers);
+	if ( handlers != NULL ) {
+		// don't use a vector because it will use malloc/free and we want notifcation to be low cost
+        allImagesLock();
+        ImageLoader* images[sAllImages.size()+1];
+        ImageLoader** end = images;
+        for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+            dyld_image_states imageState = (*it)->getState();
+            if ( (imageState == state) || (orLater && (imageState > state)) )
+                *end++ = *it;
+        }
+		if ( sBundleBeingLoaded != NULL ) {
+			dyld_image_states imageState = sBundleBeingLoaded->getState();
+			if ( (imageState == state) || (orLater && (imageState > state)) )
+				*end++ = sBundleBeingLoaded;
+		}
+        const char* dontLoadReason = NULL;
+		unsigned int count = end-images;
+		if ( end != images ) {
+			// sort bottom up
+			qsort(images, count, sizeof(ImageLoader*), &imageSorter);
+			// build info array
+			dyld_image_info	infos[count];
+			for (unsigned int i=0; i < count; ++i) {
+				dyld_image_info* p = &infos[i];
+				ImageLoader* image = images[i];
+				//dyld::log("  state=%d, name=%s\n", state, image->getPath());
+				p->imageLoadAddress = image->machHeader();
+				p->imageFilePath = image->getRealPath();
+				p->imageFileModDate = image->lastModified();
+				// special case for add_image hook
+				if ( state == dyld_image_state_bound )
+					notifyAddImageCallbacks(image);
+			}
+			
+			if ( onlyHandler != NULL ) {
+				const char* result = (*onlyHandler)(state, count, infos);
+				if ( (result != NULL) && (state == dyld_image_state_dependents_mapped) ) {
+					//fprintf(stderr, "  images rejected by handler=%p\n", onlyHandler);
+					// make copy of thrown string so that later catch clauses can free it
+					dontLoadReason = strdup(result);
+				}
+			}
+			else {
+				// call each handler with whole array 
+				for (std::vector<dyld_image_state_change_handler>::iterator it = handlers->begin(); it != handlers->end(); ++it) {
+					const char* result = (*it)(state, count, infos);
+					if ( (result != NULL) && (state == dyld_image_state_dependents_mapped) ) {
+						//fprintf(stderr, "  images rejected by handler=%p\n", *it);
+						// make copy of thrown string so that later catch clauses can free it
+						dontLoadReason = strdup(result);
+						break;
+					}
+				}
+			}
+		}
+        allImagesUnlock();
+        if ( dontLoadReason != NULL )
+            throw dontLoadReason;
+	}
+#if CORESYMBOLICATION_SUPPORT
+	if ( state == dyld_image_state_rebased ) {
+		if ( sEnv.DYLD_PRINT_CS_NOTIFICATIONS ) {
+			for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+				dyld_image_states imageState = (*it)->getState();
+				if ( (imageState == dyld_image_state_rebased) || (orLater && (imageState > dyld_image_state_rebased)) )
+					dyld::log("dyld core symbolication load notification: %p %s\n", (*it)->machHeader(), (*it)->getPath());
+			}
+		}
+		if ( dyld_all_image_infos.coreSymbolicationShmPage != NULL) {
+			CSCppDyldSharedMemoryPage* connection = (CSCppDyldSharedMemoryPage*)dyld_all_image_infos.coreSymbolicationShmPage;
+			if ( connection->is_valid_version() ) {
+				// This needs to be captured now
+				uint64_t load_timestamp = mach_absolute_time();
+				for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+					dyld_image_states imageState = (*it)->getState();
+					if ( (imageState == state) || (orLater && (imageState > state)) )
+						coresymbolication_load_image(connection, *it, load_timestamp);
+				}
+			}
+		}
+	}
+#endif
+}
+
+
+
+static void notifyBatch(dyld_image_states state)
+{
+	notifyBatchPartial(state, false, NULL);
+}
 
 // In order for register_func_for_add_image() callbacks to to be called bottom up,
 // we need to maintain a list of root images. The main executable is usally the
@@ -208,35 +750,85 @@
 // If DYLD_INSERT_LIBRARIES is used, those libraries are first.
 static void addRootImage(ImageLoader* image)
 {
-	//fprintf(stderr, "addRootImage(%p, %s)\n", image, image->getPath());
+	//dyld::log("addRootImage(%p, %s)\n", image, image->getPath());
 	// add to list of roots
 	sImageRoots.push_back(image);
 }
 
-// Objective-C will contain a __DATA/__image_notify section which contains pointers to a function to call
-// whenever any new image is loaded.
-static void addImageNeedingNotification(ImageLoader* image)
-{
-	sImagesToNotifyAboutOtherImages.push_back(image);
-}
+
+static void clearAllDepths()
+{
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++)
+		(*it)->clearDepth();
+}
+
+static void printAllDepths()
+{
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++)
+		dyld::log("%03d %s\n",  (*it)->getDepth(), (*it)->getShortName());
+}
+
+
+static unsigned int imageCount()
+{
+	return sAllImages.size();
+}
+
+
+static void setNewProgramVars(const ProgramVars& newVars)
+{
+	// make a copy of the pointers to program variables
+	gLinkContext.programVars = newVars;
+	
+	// now set each program global to their initial value
+	*gLinkContext.programVars.NXArgcPtr = gLinkContext.argc;
+	*gLinkContext.programVars.NXArgvPtr = gLinkContext.argv;
+	*gLinkContext.programVars.environPtr = gLinkContext.envp;
+	*gLinkContext.programVars.__prognamePtr = gLinkContext.progname;
+}
+
+#if SUPPORT_OLD_CRT_INITIALIZATION
+static void setRunInitialzersOldWay()
+{
+	gRunInitializersOldWay = true;		
+}
+#endif
 
 static void addImage(ImageLoader* image)
 {
 	// add to master list
-	sAllImages.push_back(image);
+    allImagesLock();
+        sAllImages.push_back(image);
+    allImagesUnlock();
+	
+	// update mapped ranges
+	uintptr_t lastSegStart = 0;
+	uintptr_t lastSegEnd = 0;
+	for(unsigned int i=0, e=image->segmentCount(); i < e; ++i) {
+		if ( image->segUnaccessible(i) ) 
+			continue;
+		uintptr_t start = image->segActualLoadAddress(i);
+		uintptr_t end = image->segActualEndAddress(i);
+		if ( start == lastSegEnd ) {
+			// two segments are contiguous, just record combined segments
+			lastSegEnd = end;
+		}
+		else {
+			// non-contiguous segments, record last (if any)
+			if ( lastSegEnd != 0 )
+				addMappedRange(image, lastSegStart, lastSegEnd);
+			lastSegStart = start;
+			lastSegEnd = end;
+		}		
+	}
+	if ( lastSegEnd != 0 )
+		addMappedRange(image, lastSegStart, lastSegEnd);
+
 	
 	if ( sEnv.DYLD_PRINT_LIBRARIES || (sEnv.DYLD_PRINT_LIBRARIES_POST_LAUNCH && (sMainExecutable!=NULL) && sMainExecutable->isLinked()) ) {
-		uint64_t offset = image->getOffsetInFatFile();
-		if ( offset == 0 )
-			fprintf(stderr, "dyld: loaded: %s\n", image->getPath());
-		else
-			fprintf(stderr, "dyld: loaded: %s, cpu-sub-type: %d\n", image->getPath(), image->machHeader()->cpusubtype);
-	}
-	
-#if OLD_GDB_DYLD_INTERFACE
-	// let gdb find out about this
-	addImageForgdb(image->machHeader(), image->getSlide(), image->getPath(), image->getLogicalPath());
-#endif
+		dyld::log("dyld: loaded: %s\n", image->getPath());
+	}
+	
 }
 
 void removeImage(ImageLoader* image)
@@ -250,40 +842,49 @@
 		}
 	}
 	
-	// tell all register add image handlers about this
-	// do this before removing image from internal data structures so that the callback can querey dyld about the image
-	for (std::vector<ImageCallback>::iterator it=sRemoveImageCallbacks.begin(); it != sRemoveImageCallbacks.end(); it++) {
-		(*it)(image->machHeader(), image->getSlide());
-	}
-	
-	// tell all interested images
-	for (std::vector<ImageLoader*>::iterator it=sImagesToNotifyAboutOtherImages.begin(); it != sImagesToNotifyAboutOtherImages.end(); it++) {
-		dyld_image_info info;
-		info.imageLoadAddress = image->machHeader();
-		info.imageFilePath = image->getPath();
-		info.imageFileModDate = image->lastModified();
-		(*it)->doNotification(dyld_image_removing, 1, &info);
-	}
+	// if has dtrace DOF section, tell dtrace it is going away, then remove from sImageFilesNeedingDOFUnregistration
+	for (std::vector<RegisteredDOF>::iterator it=sImageFilesNeedingDOFUnregistration.begin(); it != sImageFilesNeedingDOFUnregistration.end(); ) {
+		if ( it->mh == image->machHeader() ) {
+			unregisterDOF(it->registrationID);
+			sImageFilesNeedingDOFUnregistration.erase(it);
+			// don't increment iterator, the erase caused next element to be copied to where this iterator points
+		}
+		else {
+			++it;
+		}
+	}
+	
+	// tell all registered remove image handlers about this
+	// do this before removing image from internal data structures so that the callback can query dyld about the image
+	if ( image->getState() >= dyld_image_state_bound ) {
+		for (std::vector<ImageCallback>::iterator it=sRemoveImageCallbacks.begin(); it != sRemoveImageCallbacks.end(); it++) {
+			(*it)(image->machHeader(), image->getSlide());
+		}
+	}
+	
+	// notify 
+	notifySingle(dyld_image_state_terminated, image);
+	
+	// <rdar://problem/7740779> dyld should directly call __cxa_finalize()
+	if ( (gLibSystemHelpers != NULL) && (gLibSystemHelpers->version >= 8) )
+		(*gLibSystemHelpers->cxa_finalize)(image->machHeader());
+	
+	// remove from mapped images table
+	removedMappedRanges(image);
 
 	// remove from master list
-	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
-		if ( *it == image ) {
-			sAllImages.erase(it);
-			break;
-		}
-	}
-	
-	// flush find-by-address cache
+    allImagesLock();
+        for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+            if ( *it == image ) {
+                sAllImages.erase(it);
+                break;
+            }
+        }
+    allImagesUnlock();
+	
+	// flush find-by-address cache (do this after removed from master list, so there is no chance it can come back)
 	if ( sLastImageByAddressCache == image )
 		sLastImageByAddressCache = NULL;
-
-	// if in announcement list, pull it out 
-	for (std::vector<ImageLoader*>::iterator it=sImagesToNotifyAboutOtherImages.begin(); it != sImagesToNotifyAboutOtherImages.end(); it++) {
-		if ( *it == image ) {
-			sImagesToNotifyAboutOtherImages.erase(it);
-			break;
-		}
-	}
 
 	// if in root list, pull it out 
 	for (std::vector<ImageLoader*>::iterator it=sImageRoots.begin(); it != sImageRoots.end(); it++) {
@@ -293,14 +894,13 @@
 		}
 	}
 
+	// log if requested
+	if ( sEnv.DYLD_PRINT_LIBRARIES || (sEnv.DYLD_PRINT_LIBRARIES_POST_LAUNCH && (sMainExecutable!=NULL) && sMainExecutable->isLinked()) ) {
+		dyld::log("dyld: unloaded: %s\n", image->getPath());
+	}
+
 	// tell gdb, new way
 	removeImageFromAllImages(image->machHeader());
-
-#if OLD_GDB_DYLD_INTERFACE
-	// tell gdb, old way
-	removeImageForgdb(image->machHeader());
-	gdb_dyld_state_changed();
-#endif
 }
 
 
@@ -317,24 +917,34 @@
 
 void initializeMainExecutable()
 {
+	// apply interposing to initial set of images
+	// do this before making the __IMPORT segments in shared cache read-only
+	sMainExecutable->applyInterposing(gLinkContext);
+
+	// record that we've reached this step
+	gLinkContext.startedInitializingMainExecutable = true;
+
+	// run initialzers for any inserted dylibs
+	ImageLoader::InitializerTimingList initializerTimes[sAllImages.size()];
 	const int rootCount = sImageRoots.size();
-	for(int i=0; i < rootCount; ++i) {
-		ImageLoader* image = sImageRoots[i];
-		//fprintf(stderr, "initializeMainExecutable: image = %p\n", image);
-		image->runInitializers(gLinkContext);
-	}
-/*
-	// this does not work???
-	for (std::vector<ImageLoader*>::iterator it=sImageRoots.begin(); it != sImageRoots.end(); it++) {
-		ImageLoader* image = *it;
-		fprintf(stderr, "initializeMainExecutable: image = %p\n", image);
-		// don't know why vector sometimes starts with NULL element???
-		if ( image != NULL ) 
-			image->runInitializers(gLinkContext);
-	}
-*/
+	if ( rootCount > 1 ) {
+		for(int i=1; i < rootCount; ++i) {
+			initializerTimes[0].count = 0;
+			sImageRoots[i]->runInitializers(gLinkContext, initializerTimes[0]);
+		}
+	}
+	
+	// run initializers for main executable and everything it brings up 
+	initializerTimes[0].count = 0;
+	sMainExecutable->runInitializers(gLinkContext, initializerTimes[0]);
+	
+	// register atexit() handler to run terminators in all loaded images when this process exits
+	if ( gLibSystemHelpers != NULL ) 
+		(*gLibSystemHelpers->cxa_atexit)(&runTerminators, NULL, NULL);
+
+	// dump info if requested
 	if ( sEnv.DYLD_PRINT_STATISTICS )
-		ImageLoaderMachO::printStatistics(sAllImages.size());
+		ImageLoaderMachO::printStatistics(sAllImages.size(), initializerTimes[0]);
 }
 
 bool mainExecutablePrebound()
@@ -348,27 +958,149 @@
 }
 
 
-void runTerminators()
-{
-	const unsigned int imageCount = sImageFilesNeedingTermination.size();
-	for(unsigned int i=imageCount; i > 0; --i){
-		ImageLoader* image = sImageFilesNeedingTermination[i-1];
-		image->doTermination(gLinkContext);
-	}
-	sImageFilesNeedingTermination.clear();
-}
+void runTerminators(void* extra)
+{
+	try {
+		const unsigned int imageCount = sImageFilesNeedingTermination.size();
+		for(unsigned int i=imageCount; i > 0; --i){
+			ImageLoader* image = sImageFilesNeedingTermination[i-1];
+			image->doTermination(gLinkContext);
+		}
+		sImageFilesNeedingTermination.clear();
+		notifyBatch(dyld_image_state_terminated);
+	}
+	catch (const char* msg) {
+		halt(msg);
+	}
+}
+
+
+#if SUPPORT_VERSIONED_PATHS
+
+// forward reference
+static bool getDylibVersionAndInstallname(const char* dylibPath, uint32_t* version, char* installName);
 
 
 //
-// Turns a colon separated list of strings
-// into a NULL terminated array of string 
-// pointers.
+// Examines a dylib file and if its current_version is newer than the installed
+// dylib at its install_name, then add the dylib file to sDylibOverrides.
 //
-static const char** parseColonList(const char* list)
-{
-	if ( list[0] == '\0' )
-		return NULL;
-
+static void checkDylibOverride(const char* dylibFile)
+{
+	//dyld::log("checkDylibOverride('%s')\n", dylibFile);
+	uint32_t altVersion;
+ 	char sysInstallName[PATH_MAX];
+	if ( getDylibVersionAndInstallname(dylibFile, &altVersion, sysInstallName) ) {
+		//dyld::log("%s has version 0x%08X and install name %s\n", dylibFile, altVersion, sysInstallName);
+		uint32_t sysVersion;
+		if ( getDylibVersionAndInstallname(sysInstallName, &sysVersion, NULL) ) {
+			//dyld::log("%s has version 0x%08X\n", sysInstallName, sysVersion);
+			if ( altVersion > sysVersion ) {
+				//dyld::log("override found: %s -> %s\n", sysInstallName, dylibFile);
+				// see if there already is an override for this dylib
+				bool entryExists = false;
+				for (std::vector<DylibOverride>::iterator it = sDylibOverrides.begin(); it != sDylibOverrides.end(); ++it) {
+					if ( strcmp(it->installName, sysInstallName) == 0 ) {
+						entryExists = true;
+						uint32_t prevVersion;
+						if ( getDylibVersionAndInstallname(it->override, &prevVersion, NULL) ) {
+							if ( altVersion > prevVersion ) {
+								// found an even newer override
+								free((void*)(it->override));
+								it->override = strdup(dylibFile);
+								break;
+							}
+						}
+					}
+				}
+				if ( ! entryExists ) {
+					DylibOverride entry;
+					entry.installName = strdup(sysInstallName);
+					entry.override = strdup(dylibFile);
+					sDylibOverrides.push_back(entry);
+					//dyld::log("added override: %s -> %s\n", entry.installName, entry.override);
+				}
+			}
+		}
+	}
+	
+}
+
+static void checkDylibOverridesInDir(const char* dirPath)
+{
+	//dyld::log("checkDylibOverridesInDir('%s')\n", dirPath);
+	char dylibPath[PATH_MAX];
+	int dirPathLen = strlen(dirPath);
+	strlcpy(dylibPath, dirPath, PATH_MAX); 
+	DIR* dirp = opendir(dirPath);
+	if ( dirp != NULL) {
+		dirent entry;
+		dirent* entp = NULL;
+		while ( readdir_r(dirp, &entry, &entp) == 0 ) {
+			if ( entp == NULL )
+				break;
+			if ( entp->d_type != DT_REG ) 
+				continue;
+			dylibPath[dirPathLen] = '/';     
+			dylibPath[dirPathLen+1] = '\0';     
+			if ( strlcat(dylibPath, entp->d_name, PATH_MAX) > PATH_MAX ) 
+				continue;
+			checkDylibOverride(dylibPath);
+		}
+		closedir(dirp);
+	}
+}
+
+
+static void checkFrameworkOverridesInDir(const char* dirPath)
+{
+	//dyld::log("checkFrameworkOverridesInDir('%s')\n", dirPath);
+	char frameworkPath[PATH_MAX];
+	int dirPathLen = strlen(dirPath);
+	strlcpy(frameworkPath, dirPath, PATH_MAX); 
+	DIR* dirp = opendir(dirPath);
+	if ( dirp != NULL) {
+		dirent entry;
+		dirent* entp = NULL;
+		while ( readdir_r(dirp, &entry, &entp) == 0 ) {
+			if ( entp == NULL )
+				break;
+			if ( entp->d_type != DT_DIR ) 
+				continue;
+			frameworkPath[dirPathLen] = '/';     
+			frameworkPath[dirPathLen+1] = '\0';
+			int dirNameLen = strlen(entp->d_name);
+			if ( dirNameLen < 11 )
+				continue;
+			if ( strcmp(&entp->d_name[dirNameLen-10], ".framework") != 0 )
+				continue;
+			if ( strlcat(frameworkPath, entp->d_name, PATH_MAX) > PATH_MAX ) 
+				continue;
+			if ( strlcat(frameworkPath, "/", PATH_MAX) > PATH_MAX ) 
+				continue;
+			if ( strlcat(frameworkPath, entp->d_name, PATH_MAX) > PATH_MAX ) 
+				continue;
+			frameworkPath[strlen(frameworkPath)-10] = '\0';
+			checkDylibOverride(frameworkPath);
+		}
+		closedir(dirp);
+	}
+}
+#endif // SUPPORT_VERSIONED_PATHS
+
+
+//
+// Turns a colon separated list of strings into a NULL terminated array 
+// of string pointers. If mainExecutableDir param is not NULL,
+// substitutes @loader_path with main executable's dir.
+//
+static const char** parseColonList(const char* list, const char* mainExecutableDir)
+{
+	static const char* sEmptyList[] = { NULL };
+
+	if ( list[0] == '\0' ) 
+		return sEmptyList;
+	
 	int colonCount = 0;
 	for(const char* s=list; *s != '\0'; ++s) {
 		if (*s == ':') 
@@ -381,22 +1113,91 @@
 	for(const char* s=list; *s != '\0'; ++s) {
 		if (*s == ':') {
 			int len = s-start;
-			char* str = new char[len+1];
-			strncpy(str, start, len);
-			str[len] = '\0';
-			start = &s[1];
-			result[index++] = str;
+			if ( (mainExecutableDir != NULL) && (strncmp(start, "@loader_path/", 13) == 0) ) {
+				int mainExecDirLen = strlen(mainExecutableDir);
+				char* str = new char[mainExecDirLen+len+1];
+				strcpy(str, mainExecutableDir);
+				strlcat(str, &start[13], mainExecDirLen+len+1);
+				str[mainExecDirLen+len-13] = '\0';
+				start = &s[1];
+				result[index++] = str;
+			}
+			else if ( (mainExecutableDir != NULL) && (strncmp(start, "@executable_path/", 17) == 0) ) {
+				int mainExecDirLen = strlen(mainExecutableDir);
+				char* str = new char[mainExecDirLen+len+1];
+				strcpy(str, mainExecutableDir);
+				strlcat(str, &start[17], mainExecDirLen+len+1);
+				str[mainExecDirLen+len-17] = '\0';
+				start = &s[1];
+				result[index++] = str;
+			}
+			else {
+				char* str = new char[len+1];
+				strncpy(str, start, len);
+				str[len] = '\0';
+				start = &s[1];
+				result[index++] = str;
+			}
 		}
 	}
 	int len = strlen(start);
-	char* str = new char[len+1];
-	strcpy(str, start);
-	result[index++] = str;
+	if ( (mainExecutableDir != NULL) && (strncmp(start, "@loader_path/", 13) == 0) ) {
+		int mainExecDirLen = strlen(mainExecutableDir);
+		char* str = new char[mainExecDirLen+len+1];
+		strcpy(str, mainExecutableDir);
+		strlcat(str, &start[13], mainExecDirLen+len+1);
+		str[mainExecDirLen+len-13] = '\0';
+		result[index++] = str;
+	}
+	else if ( (mainExecutableDir != NULL) && (strncmp(start, "@executable_path/", 17) == 0) ) {
+		int mainExecDirLen = strlen(mainExecutableDir);
+		char* str = new char[mainExecDirLen+len+1];
+		strcpy(str, mainExecutableDir);
+		strlcat(str, &start[17], mainExecDirLen+len+1);
+		str[mainExecDirLen+len-17] = '\0';
+		result[index++] = str;
+	}
+	else {
+		char* str = new char[len+1];
+		strcpy(str, start);
+		result[index++] = str;
+	}
 	result[index] = NULL;
 	
+	//dyld::log("parseColonList(%s)\n", list);
+	//for(int i=0; result[i] != NULL; ++i)
+	//	dyld::log("  %s\n", result[i]);
 	return (const char**)result;
 }
 
+static void	appendParsedColonList(const char* list, const char* mainExecutableDir, const char* const ** storage)
+{
+	const char** newlist = parseColonList(list, mainExecutableDir);
+	if ( *storage == NULL ) {
+		// first time, just set
+		*storage = newlist;
+	}
+	else {
+		// need to append to existing list
+		const char* const* existing = *storage;
+		int count = 0;
+		for(int i=0; existing[i] != NULL; ++i)
+			++count;
+		for(int i=0; newlist[i] != NULL; ++i)
+			++count;
+		const char** combinedList = new const char*[count+2];
+		int index = 0;
+		for(int i=0; existing[i] != NULL; ++i)
+			combinedList[index++] = existing[i];
+		for(int i=0; newlist[i] != NULL; ++i)
+			combinedList[index++] = newlist[i];
+		combinedList[index] = NULL;
+		// leak old arrays
+		*storage = combinedList;
+	}
+}
+
+ 
 static void paths_expand_roots(const char **paths, const char *key, const char *val)
 {
 // 	assert(val != NULL);
@@ -417,13 +1218,18 @@
 
 static void removePathWithPrefix(const char* paths[], const char* prefix)
 {
-	size_t prefixLen = strlen(prefix);
-	for(int s=0,d=0; (paths[d] != NULL) && (paths[s] != NULL); ++s, ++d) {
-		if ( strncmp(paths[s], prefix, prefixLen) == 0 )
-			++s;
-		paths[d] = paths[s];
-	}
-}
+    size_t prefixLen = strlen(prefix);
+    int skip = 0;
+    int i;
+    for(i = 0; paths[i] != NULL; ++i) {
+        if ( strncmp(paths[i], prefix, prefixLen) == 0 )
+            ++skip;
+        else
+            paths[i-skip] = paths[i];
+    }
+    paths[i-skip] = NULL;
+}
+
 
 #if 0
 static void paths_dump(const char **paths)
@@ -432,7 +1238,7 @@
   const char **strs = paths;
   while(*strs != NULL)
   {
-    fprintf(stderr, "\"%s\"\n", *strs);
+    dyld::log("\"%s\"\n", *strs);
     strs++;
   }
   return;
@@ -443,7 +1249,7 @@
 {
 	uint32_t i = 0;
 	while ( NULL != argv[i] ) {
-		fprintf(stderr, "opt[%i] = \"%s\"\n", i, argv[i]);
+		dyld::log("opt[%i] = \"%s\"\n", i, argv[i]);
 		i++;
 	}
 }
@@ -451,34 +1257,32 @@
 static void printEnvironmentVariables(const char* envp[])
 {
 	while ( NULL != *envp ) {
-		fprintf(stderr, "%s\n", *envp);
+		dyld::log("%s\n", *envp);
 		envp++;
 	}
 }
 
-
-
-void processDyldEnvironmentVarible(const char* key, const char* value)
+void processDyldEnvironmentVariable(const char* key, const char* value, const char* mainExecutableDir)
 {
 	if ( strcmp(key, "DYLD_FRAMEWORK_PATH") == 0 ) {
-		sEnv.DYLD_FRAMEWORK_PATH = parseColonList(value);
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_FRAMEWORK_PATH);
 	}
 	else if ( strcmp(key, "DYLD_FALLBACK_FRAMEWORK_PATH") == 0 ) {
-		sEnv.DYLD_FALLBACK_FRAMEWORK_PATH = parseColonList(value);
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_FALLBACK_FRAMEWORK_PATH);
 	}
 	else if ( strcmp(key, "DYLD_LIBRARY_PATH") == 0 ) {
-		sEnv.DYLD_LIBRARY_PATH = parseColonList(value);
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_LIBRARY_PATH);
 	}
 	else if ( strcmp(key, "DYLD_FALLBACK_LIBRARY_PATH") == 0 ) {
-		sEnv.DYLD_FALLBACK_LIBRARY_PATH = parseColonList(value);
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_FALLBACK_LIBRARY_PATH);
 	}
 	else if ( (strcmp(key, "DYLD_ROOT_PATH") == 0) || (strcmp(key, "DYLD_PATHS_ROOT") == 0) ) {
 		if ( strcmp(value, "/") != 0 ) {
-			sEnv.DYLD_ROOT_PATH = parseColonList(value);
-			for (int i=0; sEnv.DYLD_ROOT_PATH[i] != NULL; ++i) {
-				if ( sEnv.DYLD_ROOT_PATH[i][0] != '/' ) {
-					fprintf(stderr, "dyld: warning DYLD_ROOT_PATH not used because it contains a non-absolute path\n");
-					sEnv.DYLD_ROOT_PATH = NULL;
+			gLinkContext.rootPaths = parseColonList(value, mainExecutableDir);
+			for (int i=0; gLinkContext.rootPaths[i] != NULL; ++i) {
+				if ( gLinkContext.rootPaths[i][0] != '/' ) {
+					dyld::warn("DYLD_ROOT_PATH not used because it contains a non-absolute path\n");
+					gLinkContext.rootPaths = NULL;
 					break;
 				}
 			}
@@ -488,13 +1292,7 @@
 		gLinkContext.imageSuffix = value;
 	}
 	else if ( strcmp(key, "DYLD_INSERT_LIBRARIES") == 0 ) {
-		sEnv.DYLD_INSERT_LIBRARIES = parseColonList(value);
-	}
-	else if ( strcmp(key, "DYLD_DEBUG_TRACE") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_DEBUG_TRACE not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_ERROR_PRINT") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_ERROR_PRINT not supported\n");
+		sEnv.DYLD_INSERT_LIBRARIES = parseColonList(value, NULL);
 	}
 	else if ( strcmp(key, "DYLD_PRINT_OPTS") == 0 ) {
 		sEnv.DYLD_PRINT_OPTS = true;
@@ -502,61 +1300,38 @@
 	else if ( strcmp(key, "DYLD_PRINT_ENV") == 0 ) {
 		sEnv.DYLD_PRINT_ENV = true;
 	}
+	else if ( strcmp(key, "DYLD_DISABLE_DOFS") == 0 ) {
+		sEnv.DYLD_DISABLE_DOFS = true;
+	}
+	else if ( strcmp(key, "DYLD_DISABLE_PREFETCH") == 0 ) {
+		gLinkContext.preFetchDisabled = true;
+	}
 	else if ( strcmp(key, "DYLD_PRINT_LIBRARIES") == 0 ) {
 		sEnv.DYLD_PRINT_LIBRARIES = true;
 	}
 	else if ( strcmp(key, "DYLD_PRINT_LIBRARIES_POST_LAUNCH") == 0 ) {
 		sEnv.DYLD_PRINT_LIBRARIES_POST_LAUNCH = true;
 	}
-	else if ( strcmp(key, "DYLD_TRACE") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_TRACE not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_EBADEXEC_ONLY") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_EBADEXEC_ONLY not supported\n");
-	}
 	else if ( strcmp(key, "DYLD_BIND_AT_LAUNCH") == 0 ) {
 		sEnv.DYLD_BIND_AT_LAUNCH = true;
 	}
 	else if ( strcmp(key, "DYLD_FORCE_FLAT_NAMESPACE") == 0 ) {
 		gLinkContext.bindFlat = true;
 	}
-	else if ( strcmp(key, "DYLD_DEAD_LOCK_HANG") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_DEAD_LOCK_HANG not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_ABORT_MULTIPLE_INITS") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_ABORT_MULTIPLE_INITS not supported\n");
-	}
 	else if ( strcmp(key, "DYLD_NEW_LOCAL_SHARED_REGIONS") == 0 ) {
-		gLinkContext.sharedRegionMode = ImageLoader::kUsePrivateSharedRegion;
-	}
-	else if ( strcmp(key, "DYLD_SLIDE_AND_PACK_DYLIBS") == 0 ) {
-		gLinkContext.slideAndPackDylibs = true;
+		// ignore, no longer relevant but some scripts still set it
 	}
 	else if ( strcmp(key, "DYLD_NO_FIX_PREBINDING") == 0 ) {
-		// since the new dyld never runs fix_prebinding, no need to warn if someone does not want it run
-		//fprintf(stderr, "dyld: warning DYLD_NO_FIX_PREBINDING not supported\n");
 	}
 	else if ( strcmp(key, "DYLD_PREBIND_DEBUG") == 0 ) {
 		gLinkContext.verbosePrebinding = true;
 	}
-	else if ( strcmp(key, "DYLD_HINTS_DEBUG") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_HINTS_DEBUG not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_SAMPLE_DEBUG") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_SAMPLE_DEBUG not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_EXECUTABLE_PATH_DEBUG") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_EXECUTABLE_PATH_DEBUG not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_TWO_LEVEL_DEBUG") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_TWO_LEVEL_DEBUG not supported\n");
-	}
-	else if ( strcmp(key, "DYLD_LAZY_INITIALIZERS") == 0 ) {
-		fprintf(stderr, "dyld: warning DYLD_LAZY_INITIALIZERS not supported\n");
-	}
 	else if ( strcmp(key, "DYLD_PRINT_INITIALIZERS") == 0 ) {
 		gLinkContext.verboseInit = true;
 	}
+	else if ( strcmp(key, "DYLD_PRINT_DOFS") == 0 ) {
+		gLinkContext.verboseDOF = true;
+	}
 	else if ( strcmp(key, "DYLD_PRINT_STATISTICS") == 0 ) {
 		sEnv.DYLD_PRINT_STATISTICS = true;
 	}
@@ -566,6 +1341,9 @@
 	else if ( strcmp(key, "DYLD_PRINT_BINDINGS") == 0 ) {
 		gLinkContext.verboseBind = true;
 	}
+	else if ( strcmp(key, "DYLD_PRINT_WEAK_BINDINGS") == 0 ) {
+		gLinkContext.verboseWeakBind = true;
+	}
 	else if ( strcmp(key, "DYLD_PRINT_REBASINGS") == 0 ) {
 		gLinkContext.verboseRebase = true;
 	}
@@ -574,6 +1352,15 @@
 	}
 	else if ( strcmp(key, "DYLD_PRINT_WARNINGS") == 0 ) {
 		gLinkContext.verboseWarnings = true;
+	}
+	else if ( strcmp(key, "DYLD_PRINT_RPATHS") == 0 ) {
+		gLinkContext.verboseRPaths = true;
+	}
+	else if ( strcmp(key, "DYLD_PRINT_CS_NOTIFICATIONS") == 0 ) {
+		sEnv.DYLD_PRINT_CS_NOTIFICATIONS = true;
+	}
+	else if ( strcmp(key, "DYLD_PRINT_INTERPOSING") == 0 ) {
+		gLinkContext.verboseInterposing = true;
 	}
 	else if ( strcmp(key, "DYLD_SHARED_REGION") == 0 ) {
 		if ( strcmp(value, "private") == 0 ) {
@@ -589,9 +1376,17 @@
 			gLinkContext.sharedRegionMode = ImageLoader::kUseSharedRegion;
 		}
 		else {
-			fprintf(stderr, "dyld: warning unknown option to DYLD_SHARED_REGION.  Valid options are: use, private, avoid\n");
-		}
-	}
+			dyld::warn("unknown option to DYLD_SHARED_REGION.  Valid options are: use, private, avoid\n");
+		}
+	}
+#if DYLD_SHARED_CACHE_SUPPORT
+	else if ( strcmp(key, "DYLD_SHARED_CACHE_DIR") == 0 ) {
+        sSharedCacheDir = value;
+	}
+	else if ( strcmp(key, "DYLD_SHARED_CACHE_DONT_VALIDATE") == 0 ) {
+		sSharedCacheIgnoreInodeAndTimeStamp = true;
+	}
+#endif
 	else if ( strcmp(key, "DYLD_IGNORE_PREBINDING") == 0 ) {
 		if ( strcmp(value, "all") == 0 ) {
 			gLinkContext.prebindUsage = ImageLoader::kUseNoPrebinding;
@@ -606,13 +1401,85 @@
 			gLinkContext.prebindUsage = ImageLoader::kUseSplitSegPrebinding;
 		}
 		else {
-			fprintf(stderr, "dyld: warning unknown option to DYLD_IGNORE_PREBINDING.  Valid options are: all, app, nonsplit\n");
-		}
-	}
+			dyld::warn("unknown option to DYLD_IGNORE_PREBINDING.  Valid options are: all, app, nonsplit\n");
+		}
+	}
+#if SUPPORT_VERSIONED_PATHS
+	else if ( strcmp(key, "DYLD_VERSIONED_LIBRARY_PATH") == 0 ) {
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_VERSIONED_LIBRARY_PATH);
+	}
+	else if ( strcmp(key, "DYLD_VERSIONED_FRAMEWORK_PATH") == 0 ) {
+		appendParsedColonList(value, mainExecutableDir, &sEnv.DYLD_VERSIONED_FRAMEWORK_PATH);
+	}
+#endif
 	else {
-		fprintf(stderr, "dyld: warning, unknown environment variable: %s\n", key);
-	}
-}
+		dyld::warn("unknown environment variable: %s\n", key);
+	}
+}
+
+
+#if SUPPORT_LC_DYLD_ENVIRONMENT
+static void checkLoadCommandEnvironmentVariables()
+{
+	// <rdar://problem/8440934> Support augmenting dyld environment variables in load commands
+	const uint32_t cmd_count = sMainExecutableMachHeader->ncmds;
+	const struct load_command* const cmds = (struct load_command*)(((char*)sMainExecutableMachHeader)+sizeof(macho_header));
+	const struct load_command* cmd = cmds;
+	for (uint32_t i = 0; i < cmd_count; ++i) {
+		switch (cmd->cmd) {
+			case LC_DYLD_ENVIRONMENT:
+			{
+				const struct dylinker_command* envcmd = (struct dylinker_command*)cmd;
+				const char* keyEqualsValue = (char*)envcmd + envcmd->name.offset;
+				char mainExecutableDir[strlen(sExecPath)];
+				strcpy(mainExecutableDir, sExecPath);
+				char* lastSlash = strrchr(mainExecutableDir, '/');
+				if ( lastSlash != NULL)
+					lastSlash[1] = '\0';
+				// only process variables that start with DYLD_ and end in _PATH
+				if ( (strncmp(keyEqualsValue, "DYLD_", 5) == 0) ) {
+					const char* equals = strchr(keyEqualsValue, '=');
+					if ( equals != NULL ) {
+						if ( strncmp(&equals[-5], "_PATH", 5) == 0 ) {
+							const char* value = &equals[1];
+							const int keyLen = equals-keyEqualsValue;
+							char key[keyLen+1];
+							strncpy(key, keyEqualsValue, keyLen);
+							key[keyLen] = '\0';
+							//dyld::log("processing: %s\n", keyEqualsValue);
+							//dyld::log("mainExecutableDir: %s\n", mainExecutableDir);
+							processDyldEnvironmentVariable(key, value, mainExecutableDir);
+						}
+					}
+				}
+			}
+			break;
+		}
+		cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+	}
+}
+#endif // SUPPORT_LC_DYLD_ENVIRONMENT	
+
+
+#if SUPPORT_VERSIONED_PATHS
+static void checkVersionedPaths()
+{
+	// search DYLD_VERSIONED_LIBRARY_PATH directories for dylibs and check if they are newer
+	if ( sEnv.DYLD_VERSIONED_LIBRARY_PATH != NULL ) {
+		for(const char* const* lp = sEnv.DYLD_VERSIONED_LIBRARY_PATH; *lp != NULL; ++lp) {
+			checkDylibOverridesInDir(*lp);
+		}
+	}
+	
+	// search DYLD_VERSIONED_FRAMEWORK_PATH directories for dylibs and check if they are newer
+	if ( sEnv.DYLD_VERSIONED_FRAMEWORK_PATH != NULL ) {
+		for(const char* const* fp = sEnv.DYLD_VERSIONED_FRAMEWORK_PATH; *fp != NULL; ++fp) {
+			checkFrameworkOverridesInDir(*fp);
+		}
+	}
+}
+#endif	
+
 
 //
 // For security, setuid programs ignore DYLD_* environment variables.
@@ -633,6 +1500,22 @@
 		}
 	}
 	*d++ = NULL;
+	if ( removedCount != 0 ) {
+		dyld::log("dyld: DYLD_ environment variables being ignored because ");
+		switch (sRestrictedReason) {
+			case restrictedNot:
+				break;
+			case restrictedBySetGUid:
+				dyld::log("main executable (%s) is setuid or setgid\n", sExecPath);
+				break;
+			case restrictedBySegment:
+				dyld::log("main executable (%s) has __RESTRICT/__restrict section\n", sExecPath);
+				break;
+			case restrictedByEntitlements:
+				dyld::log("main executable (%s) is code signed with entitlements\n", sExecPath);
+				break;
+		}
+	}
 	
 	// slide apple parameters
 	if ( removedCount > 0 ) {
@@ -640,22 +1523,15 @@
 		do {
 			*d = d[removedCount];
 		} while ( *d++ != NULL );
-	}
-	
-	// setup DYLD_FALLBACK_FRAMEWORK_PATH, if not set in environment
-	if ( sEnv.DYLD_FALLBACK_FRAMEWORK_PATH == NULL ) {
-		const char** paths = sFrameworkFallbackPaths;
-		removePathWithPrefix(paths, "$HOME");
-		sEnv.DYLD_FALLBACK_FRAMEWORK_PATH = paths;
-	}
-
-	// default value for DYLD_FALLBACK_LIBRARY_PATH, if not set in environment
-	if ( sEnv.DYLD_FALLBACK_LIBRARY_PATH == NULL ) {
-		const char** paths = sLibraryFallbackPaths;
-		removePathWithPrefix(paths, "$HOME");
-		sEnv.DYLD_FALLBACK_LIBRARY_PATH = paths;
-	}
-}
+		for(int i=0; i < removedCount; ++i)
+			*d++ = NULL;
+	}
+	
+	// disable framework and library fallback paths for setuid binaries rdar://problem/4589305
+	sEnv.DYLD_FALLBACK_FRAMEWORK_PATH = NULL;
+	sEnv.DYLD_FALLBACK_LIBRARY_PATH = NULL;
+}
+
 
 static void checkEnvironmentVariables(const char* envp[], bool ignoreEnviron)
 {
@@ -671,7 +1547,7 @@
 				char key[keyLen+1];
 				strncpy(key, keyEqualsValue, keyLen);
 				key[keyLen] = '\0';
-				processDyldEnvironmentVarible(key, value);
+				processDyldEnvironmentVariable(key, value, NULL);
 			}
 		}
 	    else if ( strncmp(keyEqualsValue, "HOME=", 5) == 0 ) {
@@ -679,10 +1555,14 @@
 		}
 		else if ( strncmp(keyEqualsValue, "LD_LIBRARY_PATH=", 16) == 0 ) {
 			const char* path = &keyEqualsValue[16];
-			sEnv.LD_LIBRARY_PATH = parseColonList(path);
-		}
-	}
-		
+			sEnv.LD_LIBRARY_PATH = parseColonList(path, NULL);
+		}
+	}
+
+#if SUPPORT_LC_DYLD_ENVIRONMENT
+	checkLoadCommandEnvironmentVariables();
+#endif // SUPPORT_LC_DYLD_ENVIRONMENT	
+	
 	// default value for DYLD_FALLBACK_FRAMEWORK_PATH, if not set in environment
 	if ( sEnv.DYLD_FALLBACK_FRAMEWORK_PATH == NULL ) {
 		const char** paths = sFrameworkFallbackPaths;
@@ -702,137 +1582,103 @@
 			paths_expand_roots(paths, "$HOME", home);
 		sEnv.DYLD_FALLBACK_LIBRARY_PATH = paths;
 	}
+	
+#if SUPPORT_VERSIONED_PATHS
+	checkVersionedPaths();
+#endif	
 }
 
 
 static void getHostInfo()
 {
-#if 0
+#if CPU_SUBTYPES_SUPPORTED
+#if __ARM_ARCH_7A__
+	sHostCPU		= CPU_TYPE_ARM;
+	sHostCPUsubtype = CPU_SUBTYPE_ARM_V7;
+#elif __ARM_ARCH_6K__
+	sHostCPU		= CPU_TYPE_ARM;
+	sHostCPUsubtype = CPU_SUBTYPE_ARM_V6;
+#elif __ARM_ARCH_7F__
+	sHostCPU		= CPU_TYPE_ARM;
+	sHostCPUsubtype = CPU_SUBTYPE_ARM_V7F;
+#elif __ARM_ARCH_7S__
+	sHostCPU		= CPU_TYPE_ARM;
+	sHostCPUsubtype = CPU_SUBTYPE_ARM_V7S;
+#elif __ARM_ARCH_7K__
+	sHostCPU		= CPU_TYPE_ARM;
+	sHostCPUsubtype = CPU_SUBTYPE_ARM_V7K;
+#else
 	struct host_basic_info info;
 	mach_msg_type_number_t count = HOST_BASIC_INFO_COUNT;
 	mach_port_t hostPort = mach_host_self();
 	kern_return_t result = host_info(hostPort, HOST_BASIC_INFO, (host_info_t)&info, &count);
-	mach_port_deallocate(mach_task_self(), hostPort);
 	if ( result != KERN_SUCCESS )
 		throw "host_info() failed";
-	
 	sHostCPU		= info.cpu_type;
 	sHostCPUsubtype = info.cpu_subtype;
 #endif
-
-	size_t valSize = sizeof(sHostCPU);
-	if (sysctlbyname ("hw.cputype", &sHostCPU, &valSize, NULL, 0) != 0) 
-		throw "sysctlbyname(hw.cputype) failed";
-	valSize = sizeof(sHostCPUsubtype);
-	if (sysctlbyname ("hw.cpusubtype", &sHostCPUsubtype, &valSize, NULL, 0) != 0) 
-		throw "sysctlbyname(hw.cpusubtype) failed";
-}
-
-bool validImage(ImageLoader* possibleImage)
-{
-	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i) {
-		if ( possibleImage == sAllImages[i] ) {
-			return true;
-		}
-	}
+#endif
+}
+
+static void checkSharedRegionDisable()
+{
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+	// if main executable has segments that overlap the shared region, 
+	// then disable using the shared region
+	if ( sMainExecutable->overlapsWithAddressRange((void*)(uintptr_t)SHARED_REGION_BASE, (void*)(uintptr_t)(SHARED_REGION_BASE + SHARED_REGION_SIZE)) ) {
+		gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
+		if ( gLinkContext.verboseMapping )
+			dyld::warn("disabling shared region because main executable overlaps\n");
+	}
+#endif
+	// iPhoneOS cannot run without shared region
+}
+
+bool validImage(const ImageLoader* possibleImage)
+{
+    const unsigned int imageCount = sAllImages.size();
+    for(unsigned int i=0; i < imageCount; ++i) {
+        if ( possibleImage == sAllImages[i] ) {
+            return true;
+        }
+    }
 	return false;
 }
 
 uint32_t getImageCount()
 {
-	if ( sAllImagesMightContainUnlinkedImages ) {
-		uint32_t count = 0;
-		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
-			if ( (*it)->isLinked() )
-				++count;
-		}
-		return count;
-	}
-	else {
-		return sAllImages.size();
-	}
+	return sAllImages.size();
 }
 
 ImageLoader* getIndexedImage(unsigned int index)
 {
-	if ( sAllImagesMightContainUnlinkedImages ) {
-		uint32_t count = 0;
-		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
-			if ( (*it)->isLinked() ) {
-				if ( index == count )
-					return *it;
-				++count;
-			}
-		}
-	}
-	else {
-		if ( index < sAllImages.size() )
-			return sAllImages[index];
-	}
+	if ( index < sAllImages.size() )
+		return sAllImages[index];
 	return NULL;
 }
 
 ImageLoader* findImageByMachHeader(const struct mach_header* target)
 {
-	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i) {
-		ImageLoader* anImage = sAllImages[i];
-		if ( anImage->machHeader() == target )
+	return findMappedRange((uintptr_t)target);
+}
+
+
+ImageLoader* findImageContainingAddress(const void* addr)
+{
+	return findMappedRange((uintptr_t)addr);
+}
+
+
+ImageLoader* findImageContainingSymbol(const void* symbol)
+{
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+		ImageLoader* anImage = *it;
+		if ( anImage->containsSymbol(symbol) )
 			return anImage;
 	}
 	return NULL;
 }
 
-
-ImageLoader* findImageContainingAddress(const void* addr)
-{
-#if FIND_STATS	
-	static int cacheHit = 0; 
-	static int cacheMiss = 0; 
-	static int cacheNotMacho = 0; 
-	if ( ((cacheHit+cacheMiss+cacheNotMacho) % 100) == 0 )
-		fprintf(stderr, "findImageContainingAddress(): cache hit = %d, miss = %d, unknown = %d\n", cacheHit, cacheMiss, cacheNotMacho);
-#endif
-	// first look in image where last address was found rdar://problem/3685517
-	if ( (sLastImageByAddressCache != NULL) && sLastImageByAddressCache->containsAddress(addr) ) {
-#if FIND_STATS	
-		++cacheHit;
-#endif
-		return sLastImageByAddressCache;
-	}
-	// do exhastive search 
-	// todo: consider maintaining a list sorted by address ranges and do a binary search on that
-	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i) {
-		ImageLoader* anImage = sAllImages[i];
-		if ( anImage->containsAddress(addr) ) {
-			sLastImageByAddressCache = anImage;
-#if FIND_STATS	
-		++cacheMiss;
-#endif
-			return anImage;
-		}
-	}
-#if FIND_STATS	
-		++cacheNotMacho;
-#endif
-	return NULL;
-}
-
-ImageLoader* findImageContainingAddressThreadSafe(const void* addr)
-{
-	// do exhastive search 
-	// todo: consider maintaining a list sorted by address ranges and do a binary search on that
-	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i) {
-		ImageLoader* anImage = sAllImages[i];
-		if ( anImage->containsAddress(addr) ) {
-			return anImage;
-		}
-	}
-	return NULL;
-}
 
 
 void forEachImageDo( void (*callback)(ImageLoader*, void* userData), void* userData)
@@ -922,6 +1768,8 @@
 }
 
 
+// only for architectures that use cpu-sub-types
+#if CPU_SUBTYPES_SUPPORTED 
 
 const cpu_subtype_t CPU_SUBTYPE_END_OF_LIST = -1;
 
@@ -939,60 +1787,49 @@
 //
 
 
-//	 
-//	32-bit PowerPC sub-type lists
+#if __arm__
+//      
+//     ARM sub-type lists
 //
-const int kPPC_RowCount = 4;
-static const cpu_subtype_t kPPC32[kPPC_RowCount][6] = { 
-	// G5 can run any code
-	{  CPU_SUBTYPE_POWERPC_970, CPU_SUBTYPE_POWERPC_7450,  CPU_SUBTYPE_POWERPC_7400, CPU_SUBTYPE_POWERPC_750, CPU_SUBTYPE_POWERPC_ALL, CPU_SUBTYPE_END_OF_LIST },
-	
-	// G4 can run all but G5 code
-	{  CPU_SUBTYPE_POWERPC_7450,  CPU_SUBTYPE_POWERPC_7400,  CPU_SUBTYPE_POWERPC_750, CPU_SUBTYPE_POWERPC_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
-	{  CPU_SUBTYPE_POWERPC_7400,  CPU_SUBTYPE_POWERPC_7450,  CPU_SUBTYPE_POWERPC_750, CPU_SUBTYPE_POWERPC_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
-
-	// G3 cannot run G4 or G5 code
-	{ CPU_SUBTYPE_POWERPC_750,  CPU_SUBTYPE_POWERPC_ALL, CPU_SUBTYPE_END_OF_LIST,  CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST }
+const int kARM_RowCount = 8;
+static const cpu_subtype_t kARM[kARM_RowCount][9] = { 
+
+	// armv7f can run: v7f, v7, v6, v5, and v4
+	{  CPU_SUBTYPE_ARM_V7F, CPU_SUBTYPE_ARM_V7, CPU_SUBTYPE_ARM_V6, CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST },
+
+	// armv7k can run: v7k, v6, v5, and v4
+	{  CPU_SUBTYPE_ARM_V7K, CPU_SUBTYPE_ARM_V6, CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST },
+
+	// armv7 can run: v7, v6, v5, and v4
+	{  CPU_SUBTYPE_ARM_V7, CPU_SUBTYPE_ARM_V6, CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST },
+	
+	// armv6 can run: v6, v5, and v4
+	{  CPU_SUBTYPE_ARM_V6, CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
+	
+	// xscale can run: xscale, v5, and v4
+	{  CPU_SUBTYPE_ARM_XSCALE, CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
+	
+	// armv5 can run: v5 and v4
+	{  CPU_SUBTYPE_ARM_V5TEJ, CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
+
+	// armv4 can run: v4
+	{  CPU_SUBTYPE_ARM_V4T, CPU_SUBTYPE_ARM_ALL, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST, CPU_SUBTYPE_END_OF_LIST },
 };
-
-
-//	 
-//	64-bit PowerPC sub-type lists
-//
-const int kPPC64_RowCount = 1;
-static const cpu_subtype_t kPPC64[kPPC64_RowCount][3] = { 
-	// G5 can run any 64-bit code
-	{  CPU_SUBTYPE_POWERPC_970, CPU_SUBTYPE_POWERPC_ALL, CPU_SUBTYPE_END_OF_LIST },
-};
-
-
-
-//	 
-//	32-bit x86 sub-type lists
-//
-//	TO-DO
-
+#endif
 
 
 // scan the tables above to find the cpu-sub-type-list for this machine
 static const cpu_subtype_t* findCPUSubtypeList(cpu_type_t cpu, cpu_subtype_t subtype)
 {
 	switch (cpu) {
-		case CPU_TYPE_POWERPC:
-			for (int i=0; i < kPPC_RowCount ; ++i) {
-				if ( kPPC32[i][0] == subtype )
-					return kPPC32[i];
+#if __arm__
+		case CPU_TYPE_ARM:
+			for (int i=0; i < kARM_RowCount ; ++i) {
+				if ( kARM[i][0] == subtype )
+					return kARM[i];
 			}
 			break;
-		case CPU_TYPE_POWERPC64:
-			for (int i=0; i < kPPC64_RowCount ; ++i) {
-				if ( kPPC64[i][0] == subtype )
-					return kPPC64[i];
-			}
-			break;
-		case CPU_TYPE_I386:
-			// To do 
-			break;
+#endif
 	}
 	return NULL;
 }
@@ -1007,7 +1844,7 @@
 	for (uint32_t subTypeIndex=0; list[subTypeIndex] != CPU_SUBTYPE_END_OF_LIST; ++subTypeIndex) {
 		for(uint32_t fatIndex=0; fatIndex < OSSwapBigToHostInt32(fh->nfat_arch); ++fatIndex) {
 			if ( ((cpu_type_t)OSSwapBigToHostInt32(archs[fatIndex].cputype) == cpu) 
-				&& (list[subTypeIndex] == archs[fatIndex].cpusubtype) ) {
+				&& (list[subTypeIndex] == (cpu_subtype_t)OSSwapBigToHostInt32(archs[fatIndex].cpusubtype)) ) {
 				*offset = OSSwapBigToHostInt32(archs[fatIndex].offset);
 				*len = OSSwapBigToHostInt32(archs[fatIndex].size);
 				return true;
@@ -1039,27 +1876,22 @@
 	for(uint32_t i=0; i < OSSwapBigToHostInt32(fh->nfat_arch); ++i) {
 		if ( (cpu_type_t)OSSwapBigToHostInt32(archs[i].cputype) == cpu) {
 			switch (cpu) {
-				case CPU_TYPE_POWERPC:
-				case CPU_TYPE_POWERPC64:
-					if ( (cpu_subtype_t)OSSwapBigToHostInt32(archs[i].cpusubtype) == CPU_SUBTYPE_POWERPC_ALL ) {
+#if __arm__
+				case CPU_TYPE_ARM:
+					if ( (cpu_subtype_t)OSSwapBigToHostInt32(archs[i].cpusubtype) == CPU_SUBTYPE_ARM_ALL ) {
 						*offset = OSSwapBigToHostInt32(archs[i].offset);
 						*len = OSSwapBigToHostInt32(archs[i].size);
 						return true;
 					}
 					break;
-				case CPU_TYPE_I386:
-					if ( (cpu_subtype_t)OSSwapBigToHostInt32(archs[i].cpusubtype) == CPU_SUBTYPE_I386_ALL ) {
-						*offset = OSSwapBigToHostInt32(archs[i].offset);
-						*len = OSSwapBigToHostInt32(archs[i].size);
-						return true;
-					}
-					break;
+#endif
 			}
 		}
 	}
 	return false;
 }
 
+#endif // CPU_SUBTYPES_SUPPORTED
 
 //
 // A fat file may contain multiple sub-images for the same cpu-type,
@@ -1068,6 +1900,7 @@
 //
 static bool fatFindBest(const fat_header* fh, uint64_t* offset, uint64_t* len)
 {
+#if CPU_SUBTYPES_SUPPORTED
 	// assume all dylibs loaded must have same cpu type as main executable
 	const cpu_type_t cpu = sMainExecutableMachHeader->cputype;
 
@@ -1087,20 +1920,32 @@
 	
 	// running on an uknown cpu, can only load generic code
 	return fatFindRunsOnAllCPUs(cpu, fh, offset, len);
+#else
+	// just find first slice with matching architecture
+	const fat_arch* archs = (fat_arch*)(((char*)fh)+sizeof(fat_header));
+	for(uint32_t i=0; i < OSSwapBigToHostInt32(fh->nfat_arch); ++i) {
+		if ( (cpu_type_t)OSSwapBigToHostInt32(archs[i].cputype) == sMainExecutableMachHeader->cputype) {
+			*offset = OSSwapBigToHostInt32(archs[i].offset);
+			*len = OSSwapBigToHostInt32(archs[i].size);
+			return true;
+		}
+	}
+	return false;
+#endif
 }
 
 
 
 //
 // This is used to validate if a non-fat (aka thin or raw) mach-o file can be used
-// on the current processor.  It is deemed compatible if any of the following are true:
-//  1) mach_header subtype is in list of compatible subtypes for running processor
-//  2) mach_header subtype is same as running processor subtype
-//  3) mach_header subtype runs on all processor variants
-//
-//
-bool isCompatibleMachO(const uint8_t* firstPage)
-{
+// on the current processor. //
+bool isCompatibleMachO(const uint8_t* firstPage, const char* path)
+{
+#if CPU_SUBTYPES_SUPPORTED
+	// It is deemed compatible if any of the following are true:
+	//  1) mach_header subtype is in list of compatible subtypes for running processor
+	//  2) mach_header subtype is same as running processor subtype
+	//  3) mach_header subtype runs on all processor variants
 	const mach_header* mh = (mach_header*)firstPage;
 	if ( mh->magic == sMainExecutableMachHeader->magic ) {
 		if ( mh->cputype == sMainExecutableMachHeader->cputype ) {
@@ -1114,39 +1959,45 @@
 							return true;
 					}
 					// have list and not in list, so not compatible
-					throw "incompatible cpu-subtype";
+					throwf("incompatible cpu-subtype: 0x%08X in %s", mh->cpusubtype, path);
 				}
 				// unknown cpu sub-type, but if exact match for current subtype then ok to use
 				if ( mh->cpusubtype == sHostCPUsubtype ) 
 					return true;
 			}
 			
-			// cpu unknown, so don't know if subtype is compatible
-			// only load _ALL variant
+			// cpu type has no ordered list of subtypes
 			switch (mh->cputype) {
-				case CPU_TYPE_POWERPC:
-				case CPU_TYPE_POWERPC64:
-					if ( mh->cpusubtype == CPU_SUBTYPE_POWERPC_ALL ) 
-						return true;
-					break;
 				case CPU_TYPE_I386:
-					if ( mh->cpusubtype == CPU_SUBTYPE_I386_ALL ) 
-						return true;
-					break;					
-			}
-		}
-	}
+				case CPU_TYPE_X86_64:
+					// subtypes are not used or these architectures
+					return true;
+			}
+		}
+	}
+#else
+	// For architectures that don't support cpu-sub-types
+	// this just check the cpu type.
+	const mach_header* mh = (mach_header*)firstPage;
+	if ( mh->magic == sMainExecutableMachHeader->magic ) {
+		if ( mh->cputype == sMainExecutableMachHeader->cputype ) {
+			return true;
+		}
+	}
+#endif
 	return false;
 }
+
+
 
 
 // The kernel maps in main executable before dyld gets control.  We need to 
 // make an ImageLoader* for the already mapped in main executable.
-static ImageLoader* instantiateFromLoadedImage(const struct mach_header* mh, const char* path)
+static ImageLoader* instantiateFromLoadedImage(const macho_header* mh, uintptr_t slide, const char* path)
 {
 	// try mach-o loader
-	if ( isCompatibleMachO((const uint8_t*)mh) ) {
-		ImageLoader* image = new ImageLoaderMachO(path, mh, 0, gLinkContext);
+	if ( isCompatibleMachO((const uint8_t*)mh, path) ) {
+		ImageLoader* image = ImageLoaderMachO::instantiateMainExecutable(mh, slide, path, gLinkContext);
 		addImage(image);
 		return image;
 	}
@@ -1155,36 +2006,145 @@
 }
 
 
-
+#if DYLD_SHARED_CACHE_SUPPORT
+static bool findInSharedCacheImage(const char* path, const struct stat* stat_buf, const macho_header** mh, const char** pathInCache, long* slide)
+{
+	if ( sSharedCache != NULL ) {
+#if __MAC_OS_X_VERSION_MIN_REQUIRED	
+		// Mac OS X always requires inode/mtime to valid cache
+		// if stat() not done yet, do it now
+		struct stat statb;
+		if ( stat_buf == NULL ) {
+			if ( stat(path, &statb) == -1 )
+				return false;
+			stat_buf = &statb;
+		}
+#endif
+		// walk shared cache to see if there is a cached image that matches the inode/mtime/path desired
+		const dyld_cache_image_info* const start = (dyld_cache_image_info*)((uint8_t*)sSharedCache + sSharedCache->imagesOffset);
+		const dyld_cache_image_info* const end = &start[sSharedCache->imagesCount];
+		for( const dyld_cache_image_info* p = start; p != end; ++p) {
+#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+			// just check path
+			const char* aPath = (char*)sSharedCache + p->pathFileOffset;
+			if ( strcmp(path, aPath) == 0 ) {
+				// found image in cache
+				*mh = (macho_header*)(p->address+sSharedCacheSlide);
+				*pathInCache = aPath;
+				*slide = sSharedCacheSlide;
+				return true;
+			}
+#elif __MAC_OS_X_VERSION_MIN_REQUIRED
+			// check mtime and inode first because it is fast
+			if ( sSharedCacheIgnoreInodeAndTimeStamp 
+				|| ( ((time_t)p->modTime == stat_buf->st_mtime) && ((ino_t)p->inode == stat_buf->st_ino) ) ) {
+				// mod-time and inode match an image in the shared cache, now check path
+				const char* aPath = (char*)sSharedCache + p->pathFileOffset;
+				bool cacheHit = (strcmp(path, aPath) == 0);
+				if ( ! cacheHit ) {
+					// path does not match install name of dylib in cache, but inode and mtime does match
+					// perhaps path is a symlink to the cached dylib
+					struct stat pathInCacheStatBuf;
+					if ( stat(aPath, &pathInCacheStatBuf) != -1 )
+						cacheHit = ( (pathInCacheStatBuf.st_dev == stat_buf->st_dev) && (pathInCacheStatBuf.st_ino == stat_buf->st_ino) );	
+				}
+				if ( cacheHit ) {
+					// found image in cache, return info
+					*mh = (macho_header*)(p->address+sSharedCacheSlide);
+					//dyld::log("findInSharedCacheImage(), mh=%p, p->address=0x%0llX, slid=0x%0lX, path=%p\n", 
+					//	*mh, p->address, sSharedCacheSlide, aPath);
+					*pathInCache = aPath;
+					*slide = sSharedCacheSlide;
+					return true;
+				}
+			}
+#endif
+		}	
+	}
+	return false;
+}
+
+bool inSharedCache(const char* path)
+{
+	const macho_header* mhInCache;
+	const char*			pathInCache;
+	long				slide;
+	return findInSharedCacheImage(path, NULL, &mhInCache, &pathInCache, &slide);
+}
+
+#endif
+
+static ImageLoader* checkandAddImage(ImageLoader* image, const LoadContext& context)
+{
+	// now sanity check that this loaded image does not have the same install path as any existing image
+	const char* loadedImageInstallPath = image->getInstallPath();
+	if ( image->isDylib() && (loadedImageInstallPath != NULL) && (loadedImageInstallPath[0] == '/') ) {
+		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+			ImageLoader* anImage = *it;
+			const char* installPath = anImage->getInstallPath();
+			if ( installPath != NULL) {
+				if ( strcmp(loadedImageInstallPath, installPath) == 0 ) {
+					//dyld::log("duplicate(%s) => %p\n", installPath, anImage);
+					removeImage(image);
+					ImageLoader::deleteImage(image);
+					return anImage;
+				}
+			}
+		}
+	}
+
+	// some API's restrict what they can load
+	if ( context.mustBeBundle && !image->isBundle() )
+		throw "not a bundle";
+	if ( context.mustBeDylib && !image->isDylib() )
+		throw "not a dylib";
+
+	// regular main executables cannot be loaded 
+	if ( image->isExecutable() ) {
+		if ( !context.canBePIE || !image->isPositionIndependentExecutable() )
+			throw "can't load a main executable";
+	}
+	
+	// don't add bundles to global list, they can be loaded but not linked.  When linked it will be added to list
+	if ( ! image->isBundle() ) 
+		addImage(image);
+	
+	return image;
+}
 
 // map in file and instantiate an ImageLoader
-static ImageLoader* loadPhase6(int fd, struct stat& stat_buf, const char* path, const LoadContext& context)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase6(int fd, const struct stat& stat_buf, const char* path, const LoadContext& context)
+{
+	//dyld::log("%s(%s)\n", __func__ , path);
 	uint64_t fileOffset = 0;
 	uint64_t fileLength = stat_buf.st_size;
-#if __ppc64__
-	if ( *((uint32_t*)((char*)(&stat_buf)+0x60)) == 0xFEFEFEFE )
-		fileLength = *((uint64_t*)((char*)(&stat_buf)+0x30));	// HACK work around for kernel stat bug rdar://problem/3845883
-#endif
 
 	// validate it is a file (not directory)
 	if ( (stat_buf.st_mode & S_IFMT) != S_IFREG ) 
 		throw "not a file";
 
-	// min file is 4K
+	uint8_t firstPage[4096];
+	bool shortPage = false;
+	
+	// min mach-o file is 4K
 	if ( fileLength < 4096 ) {
-		throw "file to short";
-	}
-	
-	uint8_t firstPage[4096];
-	pread(fd, firstPage, 4096,0);
+		if ( pread(fd, firstPage, fileLength, 0) != (ssize_t)fileLength )
+			throwf("pread of short file failed: %d", errno);
+		shortPage = true;
+	} 
+	else {
+		if ( pread(fd, firstPage, 4096,0) != 4096 )
+			throwf("pread of first 4K failed: %d", errno);
+	}
 	
 	// if fat wrapper, find usable sub-file
 	const fat_header* fileStartAsFat = (fat_header*)firstPage;
 	if ( fileStartAsFat->magic == OSSwapBigToHostInt32(FAT_MAGIC) ) {
 		if ( fatFindBest(fileStartAsFat, &fileOffset, &fileLength) ) {
-			pread(fd, firstPage, 4096, fileOffset);
+			if ( (fileOffset+fileLength) > (uint64_t)(stat_buf.st_size) )
+				throwf("truncated fat file.  file length=%llu, but needed slice goes to %llu", stat_buf.st_size, fileOffset+fileLength);
+			if (pread(fd, firstPage, 4096, fileOffset) != 4096)
+				throwf("pread of fat file failed: %d", errno);
 		}
 		else {
 			throw "no matching architecture in universal wrapper";
@@ -1192,47 +2152,28 @@
 	}
 	
 	// try mach-o loader
-	if ( isCompatibleMachO(firstPage) ) {
-		char realFilePath[PATH_MAX];
-		if ( gLinkContext.slideAndPackDylibs ) {
-			// when prebinding, we always want to track the real path of images
-			if ( realpath(path, realFilePath) != NULL )
-				path = realFilePath;
-		}
-
+	if ( shortPage ) 
+		throw "file too short";
+	if ( isCompatibleMachO(firstPage, path) ) {
+
+		// only MH_BUNDLE, MH_DYLIB, and some MH_EXECUTE can be dynamically loaded
+		switch ( ((mach_header*)firstPage)->filetype ) {
+			case MH_EXECUTE:
+			case MH_DYLIB:
+			case MH_BUNDLE:
+				break;
+			default:
+				throw "mach-o, but wrong filetype";
+		}
+		
 		// instantiate an image
-		ImageLoader* image = new ImageLoaderMachO(path, fd, firstPage, fileOffset, fileLength, stat_buf, gLinkContext);
+		ImageLoader* image = ImageLoaderMachO::instantiateFromFile(path, fd, firstPage, fileOffset, fileLength, stat_buf, gLinkContext);
 		
-		// now sanity check that this loaded image does not have the same install path as any existing image
-		const char* loadedImageInstallPath = image->getInstallPath();
-		if ( image->isDylib() && (loadedImageInstallPath != NULL) && (loadedImageInstallPath[0] == '/') ) {
-			for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
-				ImageLoader* anImage = *it;
-				const char* installPath = anImage->getInstallPath();
-				if ( installPath != NULL) {
-					if ( strcmp(loadedImageInstallPath, installPath) == 0 ) {
-						//fprintf(stderr, "duplicate(%s) => %p\n", installPath, anImage);
-						delete image;
-						return anImage;
-					}
-				}
-			}
-		}
-
-		// some API's restrict what they can load
-		if ( context.mustBeBundle && !image->isBundle() )
-			throw "not a bundle";
-		if ( context.mustBeDylib && !image->isDylib() )
-			throw "not a dylib";
-
-		// don't add bundles to global list, they can be loaded but not linked.  When linked it will be added to list
-		if ( ! image->isBundle() ) 
-			addImage(image);
-
-		return image;
-	}
-	
-	// try other file formats...
+		// validate
+		return checkandAddImage(image, context);
+	}
+	
+	// try other file formats here...
 	
 	
 	// throw error about what was found
@@ -1249,62 +2190,182 @@
 }
 
 
-// try to open file
-static ImageLoader* loadPhase5open(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stdout, "%s(%s)\n", __func__, path);
-	ImageLoader* image = NULL;
+static ImageLoader* loadPhase5open(const char* path, const LoadContext& context, const struct stat& stat_buf, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
 
 	// open file (automagically closed when this function exits)
 	FileOpener file(path);
-	
-	//fprintf(stderr, "open(%s) => %d\n", path, file.getFileDescriptor() );
-	
-	if ( file.getFileDescriptor() == -1 )
+		
+	// just return NULL if file not found, but record any other errors
+	if ( file.getFileDescriptor() == -1 ) {
+		int err = errno;
+		if ( err != ENOENT ) {
+			const char* newMsg = dyld::mkstringf("%s: open() failed with errno=%d", path, err);
+			exceptions->push_back(newMsg);
+		}
 		return NULL;
-		
+	}
+
+	try {
+		return loadPhase6(file.getFileDescriptor(), stat_buf, path, context);
+	}
+	catch (const char* msg) {
+		const char* newMsg = dyld::mkstringf("%s: %s", path, msg);
+		exceptions->push_back(newMsg);
+		free((void*)msg);
+		return NULL;
+	}
+}
+
+
+#if __MAC_OS_X_VERSION_MIN_REQUIRED	
+static ImageLoader* loadPhase5load(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
+	ImageLoader* image = NULL;
+
+	// just return NULL if file not found, but record any other errors
 	struct stat stat_buf;
-#if __ppc64__
-	memset(&stat_buf, 254, sizeof(struct stat));	 // hack until rdar://problem/3845883 is fixed
-#endif
-	if ( fstat(file.getFileDescriptor(), &stat_buf) == -1)
-		throw "stat error";
+	if ( stat(path, &stat_buf) == -1 ) {
+		int err = errno;
+		if ( err != ENOENT ) {
+			exceptions->push_back(dyld::mkstringf("%s: stat() failed with errno=%d", path, err));
+		}
+		return NULL;
+	}
 	
 	// in case image was renamed or found via symlinks, check for inode match
 	image = findLoadedImage(stat_buf);
 	if ( image != NULL )
 		return image;
 	
-	// needed to implement NSADDIMAGE_OPTION_RETURN_ONLY_IF_LOADED
+	// do nothing if not already loaded and if RTLD_NOLOAD or NSADDIMAGE_OPTION_RETURN_ONLY_IF_LOADED
 	if ( context.dontLoad )
 		return NULL;
-	
-	try {
-		return loadPhase6(file.getFileDescriptor(), stat_buf, path, context);
-	}
-	catch (const char* msg) {
-		char* newMsg = new char[strlen(msg) + strlen(path) + 8];
-		sprintf(newMsg, "%s: %s", path, msg);
-		exceptions->push_back(newMsg);
-		return NULL;
-	}
-}
+
+#if DYLD_SHARED_CACHE_SUPPORT
+	// see if this image is in shared cache
+	const macho_header* mhInCache;
+	const char*			pathInCache;
+	long				slideInCache;
+	if ( findInSharedCacheImage(path, &stat_buf, &mhInCache, &pathInCache, &slideInCache) ) {
+		image = ImageLoaderMachO::instantiateFromCache(mhInCache, pathInCache, slideInCache, stat_buf, gLinkContext);
+		return checkandAddImage(image, context);
+	}
+#endif
+	// file exists and is not in dyld shared cache, so open it
+	return loadPhase5open(path, context, stat_buf, exceptions);
+}
+#endif // __MAC_OS_X_VERSION_MIN_REQUIRED
+
+
+
+#if __IPHONE_OS_VERSION_MIN_REQUIRED 
+static ImageLoader* loadPhase5stat(const char* path, const LoadContext& context, struct stat* stat_buf, 
+									int* statErrNo, bool* imageFound, std::vector<const char*>* exceptions)
+{
+	ImageLoader* image = NULL;
+	*imageFound = false;
+	*statErrNo = 0;
+	if ( stat(path, stat_buf) == 0 ) {
+		// in case image was renamed or found via symlinks, check for inode match
+		image = findLoadedImage(*stat_buf);
+		if ( image != NULL ) {
+			*imageFound = true;
+			return image;
+		}
+		// do nothing if not already loaded and if RTLD_NOLOAD 
+		if ( context.dontLoad ) {
+			*imageFound = true;
+			return NULL;
+		}
+		image = loadPhase5open(path, context, *stat_buf, exceptions);
+		if ( image != NULL ) {
+			*imageFound = true;
+			return image;
+		}
+	}
+	else {
+		*statErrNo = errno;
+	}
+	return NULL;
+}
+
+// try to open file
+static ImageLoader* loadPhase5load(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
+	struct stat stat_buf;
+	bool imageFound;
+	int statErrNo;
+	ImageLoader* image;
+#if DYLD_SHARED_CACHE_SUPPORT
+	if ( sDylibsOverrideCache ) {
+		// flag is set that allows installed framework roots to override dyld shared cache
+		image = loadPhase5stat(path, context, &stat_buf, &statErrNo, &imageFound, exceptions);
+		if ( imageFound )
+			return image;
+	}
+	// see if this image is in shared cache
+	const macho_header* mhInCache;
+	const char*			pathInCache;
+	long				slideInCache;
+	if ( findInSharedCacheImage(path, NULL, &mhInCache, &pathInCache, &slideInCache) ) {
+		// see if this image in the cache was already loaded via a different path
+		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); ++it) {
+			ImageLoader* anImage = *it;
+			if ( (const macho_header*)anImage->machHeader() == mhInCache )
+				return anImage;
+		}
+		// do nothing if not already loaded and if RTLD_NOLOAD 
+		if ( context.dontLoad )
+			return NULL;
+		// nope, so instantiate a new image from dyld shared cache
+		// <rdar://problem/7014995> zero out stat buffer so mtime, etc are zero for items from the shared cache
+		bzero(&stat_buf, sizeof(stat_buf));
+		image = ImageLoaderMachO::instantiateFromCache(mhInCache, pathInCache, slideInCache, stat_buf, gLinkContext);
+		return checkandAddImage(image, context);
+	}
+	
+	if ( !sDylibsOverrideCache ) {
+		// flag is not set, and not in cache to try opening it
+		image = loadPhase5stat(path, context, &stat_buf, &statErrNo, &imageFound, exceptions);
+		if ( imageFound )
+			return image;
+	}
+#else
+	image = loadPhase5stat(path, context, &stat_buf, &statErrNo, &imageFound, exceptions);
+	if ( imageFound )
+		return image;
+#endif
+	// just return NULL if file not found, but record any other errors
+	if ( (statErrNo != ENOENT) && (statErrNo != 0) ) {
+		exceptions->push_back(dyld::mkstringf("%s: stat() failed with errno=%d", path, statErrNo));
+	}
+	return NULL;
+}
+#endif // __IPHONE_OS_VERSION_MIN_REQUIRED
+
 
 // look for path match with existing loaded images
-static ImageLoader* loadPhase5check(const char* path, const LoadContext& context)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase5check(const char* path, const char* orgPath, const LoadContext& context)
+{
+	//dyld::log("%s(%s, %s)\n", __func__ , path, orgPath);
 	// search path against load-path and install-path of all already loaded images
 	uint32_t hash = ImageLoader::hash(path);
+	//dyld::log("check() hash=%d, path=%s\n", hash, path);
 	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
 		ImageLoader* anImage = *it;
-		// check has first to cut down on strcmp calls
-		if ( anImage->getPathHash() == hash )
+		// check hash first to cut down on strcmp calls
+		//dyld::log("    check() hash=%d, path=%s\n", anImage->getPathHash(), anImage->getPath());
+		if ( anImage->getPathHash() == hash ) {
 			if ( strcmp(path, anImage->getPath()) == 0 ) {
 				// if we are looking for a dylib don't return something else
 				if ( !context.mustBeDylib || anImage->isDylib() )
 					return anImage;
 			}
+		}
 		if ( context.matchByInstallName || anImage->matchInstallPath() ) {
 			const char* installPath = anImage->getInstallPath();
 			if ( installPath != NULL) {
@@ -1315,45 +2376,71 @@
 				}
 			}
 		}
-	}
-	
-	//fprintf(stderr, "check(%s) => NULL\n", path);
+		// an install name starting with @rpath should match by install name, not just real path
+		if ( (orgPath[0] == '@') && (strncmp(orgPath, "@rpath/", 7) == 0) ) {
+			const char* installPath = anImage->getInstallPath();
+			if ( installPath != NULL) {
+				if ( !context.mustBeDylib || anImage->isDylib() ) {
+					if ( strcmp(orgPath, installPath) == 0 )
+						return anImage;
+				}
+			}
+		}
+	}
+	
+	//dyld::log("%s(%s) => NULL\n", __func__,   path);
 	return NULL;
 }
 
 
 // open or check existing
-static ImageLoader* loadPhase5(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase5(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
+	
+	// check for specific dylib overrides
+	for (std::vector<DylibOverride>::iterator it = sDylibOverrides.begin(); it != sDylibOverrides.end(); ++it) {
+		if ( strcmp(it->installName, path) == 0 ) {
+			path = it->override;
+			break;
+		}
+	}
+	
 	if ( exceptions != NULL ) 
-		return loadPhase5open(path, context, exceptions);
+		return loadPhase5load(path, orgPath, context, exceptions);
 	else
-		return loadPhase5check(path, context);
+		return loadPhase5check(path, orgPath, context);
 }
 
 // try with and without image suffix
-static ImageLoader* loadPhase4(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase4(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
 	ImageLoader* image = NULL;
 	if (  gLinkContext.imageSuffix != NULL ) {
 		char pathWithSuffix[strlen(path)+strlen( gLinkContext.imageSuffix)+2];
 		ImageLoader::addSuffix(path,  gLinkContext.imageSuffix, pathWithSuffix);
-		image = loadPhase5(pathWithSuffix, context, exceptions);
+		image = loadPhase5(pathWithSuffix, orgPath, context, exceptions);
 	}
 	if ( image == NULL )
-		image = loadPhase5(path, context, exceptions);
+		image = loadPhase5(path, orgPath, context, exceptions);
 	return image;
 }
 
+static ImageLoader* loadPhase2(const char* path, const char* orgPath, const LoadContext& context, 
+							   const char* const frameworkPaths[], const char* const libraryPaths[], 
+							   std::vector<const char*>* exceptions); // forward reference
+
 
 // expand @ variables
-static ImageLoader* loadPhase3(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase3(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
 	ImageLoader* image = NULL;
 	if ( strncmp(path, "@executable_path/", 17) == 0 ) {
+		// executable_path cannot be in used in any binary in a setuid process rdar://problem/4589305
+		if ( sProcessIsRestricted ) 
+			throwf("unsafe use of @executable_path in %s with restricted binary", context.origin);
 		// handle @executable_path path prefix
 		const char* executablePath = sExecPath;
 		char newPath[strlen(executablePath) + strlen(path)];
@@ -1363,7 +2450,7 @@
 			strcpy(&addPoint[1], &path[17]);
 		else
 			strcpy(newPath, &path[17]);
-		image = loadPhase4(newPath, context, exceptions);
+		image = loadPhase4(newPath, orgPath, context, exceptions);
 		if ( image != NULL ) 
 			return image;
 
@@ -1377,12 +2464,15 @@
 				strcpy(&addPoint[1], &path[17]);
 			else
 				strcpy(newRealPath, &path[17]);
-			image = loadPhase4(newRealPath, context, exceptions);
+			image = loadPhase4(newRealPath, orgPath, context, exceptions);
 			if ( image != NULL ) 
 				return image;
 		}
 	}
 	else if ( (strncmp(path, "@loader_path/", 13) == 0) && (context.origin != NULL) ) {
+		// @loader_path cannot be used from the main executable of a setuid process rdar://problem/4589305
+		if ( sProcessIsRestricted && (strcmp(context.origin, sExecPath) == 0) )
+			throwf("unsafe use of @loader_path in %s with restricted binary", context.origin);
 		// handle @loader_path path prefix
 		char newPath[strlen(context.origin) + strlen(path)];
 		strcpy(newPath, context.origin);
@@ -1391,7 +2481,7 @@
 			strcpy(&addPoint[1], &path[13]);
 		else
 			strcpy(newPath, &path[13]);
-		image = loadPhase4(newPath, context, exceptions);
+		image = loadPhase4(newPath, orgPath, context, exceptions);
 		if ( image != NULL ) 
 			return image;
 		
@@ -1405,22 +2495,60 @@
 				strcpy(&addPoint[1], &path[13]);
 			else
 				strcpy(newRealPath, &path[13]);
-			image = loadPhase4(newRealPath, context, exceptions);
+			image = loadPhase4(newRealPath, orgPath, context, exceptions);
 			if ( image != NULL ) 
 				return image;
 		}
 	}
-	
-	return loadPhase4(path, context, exceptions);
+	else if ( context.implicitRPath || (strncmp(path, "@rpath/", 7) == 0) ) {
+		const char* trailingPath = (strncmp(path, "@rpath/", 7) == 0) ? &path[7] : path;
+		// substitute @rpath with all -rpath paths up the load chain
+		for(const ImageLoader::RPathChain* rp=context.rpath; rp != NULL; rp=rp->next) {
+			if (rp->paths != NULL ) {
+				for(std::vector<const char*>::iterator it=rp->paths->begin(); it != rp->paths->end(); ++it) {
+					const char* anRPath = *it;
+					char newPath[strlen(anRPath) + strlen(trailingPath)+2];
+					strcpy(newPath, anRPath);
+					strcat(newPath, "/"); 
+					strcat(newPath, trailingPath); 
+					image = loadPhase4(newPath, orgPath, context, exceptions);
+					if ( gLinkContext.verboseRPaths && (exceptions != NULL) ) {
+						if ( image != NULL ) 
+							dyld::log("RPATH successful expansion of %s to: %s\n", orgPath, newPath);
+						else
+							dyld::log("RPATH failed to expanding     %s to: %s\n", orgPath, newPath);
+					}
+					if ( image != NULL ) 
+						return image;
+				}
+			}
+		}
+		
+		// substitute @rpath with LD_LIBRARY_PATH
+		if ( sEnv.LD_LIBRARY_PATH != NULL ) {
+			image = loadPhase2(trailingPath, orgPath, context, NULL, sEnv.LD_LIBRARY_PATH, exceptions);
+			if ( image != NULL )
+				return image;
+		}
+		
+		// if this is the "open" pass, don't try to open @rpath/... as a relative path
+		if ( (exceptions != NULL) && (trailingPath != path) )
+			return NULL;
+	}
+	else if (sProcessIsRestricted && (path[0] != '/' )) {
+		throwf("unsafe use of relative rpath %s in %s with restricted binary", path, context.origin);
+	}
+	
+	return loadPhase4(path, orgPath, context, exceptions);
 }
 
 
 // try search paths
-static ImageLoader* loadPhase2(const char* path, const LoadContext& context, 
+static ImageLoader* loadPhase2(const char* path, const char* orgPath, const LoadContext& context, 
 							   const char* const frameworkPaths[], const char* const libraryPaths[], 
 							   std::vector<const char*>* exceptions)
 {
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
 	ImageLoader* image = NULL;
 	const char* frameworkPartialPath = getFrameworkPartialPath(path);
 	if ( frameworkPaths != NULL ) {
@@ -1431,8 +2559,8 @@
 				strcpy(npath, *fp);
 				strcat(npath, "/");
 				strcat(npath, frameworkPartialPath);
-				//fprintf(stderr, "dyld: fallback framework path used: %s() -> loadPhase4(\"%s\", ...)\n", __func__, npath);
-				image = loadPhase4(npath, context, exceptions);
+				//dyld::log("dyld: fallback framework path used: %s() -> loadPhase4(\"%s\", ...)\n", __func__, npath);
+				image = loadPhase4(npath, orgPath, context, exceptions);
 				if ( image != NULL )
 					return image;
 			}
@@ -1446,8 +2574,8 @@
 			strcpy(libpath, *lp);
 			strcat(libpath, "/");
 			strcat(libpath, libraryLeafName);
-			//fprintf(stderr, "dyld: fallback library path used: %s() -> loadPhase4(\"%s\", ...)\n", __func__, libpath);
-			image = loadPhase4(libpath, context, exceptions);
+			//dyld::log("dyld: fallback library path used: %s() -> loadPhase4(\"%s\", ...)\n", __func__, libpath);
+			image = loadPhase4(libpath, orgPath, context, exceptions);
 			if ( image != NULL )
 				return image;
 		}
@@ -1456,33 +2584,36 @@
 }
 
 // try search overrides and fallbacks
-static ImageLoader* loadPhase1(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+static ImageLoader* loadPhase1(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
 	ImageLoader* image = NULL;
 
 	// handle LD_LIBRARY_PATH environment variables that force searching
 	if ( context.useLdLibraryPath && (sEnv.LD_LIBRARY_PATH != NULL) ) {
-		image = loadPhase2(path, context, NULL, sEnv.LD_LIBRARY_PATH, exceptions);
+		image = loadPhase2(path, orgPath, context, NULL, sEnv.LD_LIBRARY_PATH, exceptions);
 		if ( image != NULL )
 			return image;
 	}
 
 	// handle DYLD_ environment variables that force searching
 	if ( context.useSearchPaths && ((sEnv.DYLD_FRAMEWORK_PATH != NULL) || (sEnv.DYLD_LIBRARY_PATH != NULL)) ) {
-		image = loadPhase2(path, context, sEnv.DYLD_FRAMEWORK_PATH, sEnv.DYLD_LIBRARY_PATH, exceptions);
+		image = loadPhase2(path, orgPath, context, sEnv.DYLD_FRAMEWORK_PATH, sEnv.DYLD_LIBRARY_PATH, exceptions);
 		if ( image != NULL )
 			return image;
 	}
 	
 	// try raw path
-	image = loadPhase3(path, context, exceptions);
+	image = loadPhase3(path, orgPath, context, exceptions);
 	if ( image != NULL )
 		return image;
 	
 	// try fallback paths during second time (will open file)
-	if ( (exceptions != NULL) && ((sEnv.DYLD_FALLBACK_FRAMEWORK_PATH != NULL) || (sEnv.DYLD_FALLBACK_LIBRARY_PATH != NULL)) ) {
-		image = loadPhase2(path, context, sEnv.DYLD_FALLBACK_FRAMEWORK_PATH, sEnv.DYLD_FALLBACK_LIBRARY_PATH, exceptions);
+	const char* const* fallbackLibraryPaths = sEnv.DYLD_FALLBACK_LIBRARY_PATH;
+	if ( (fallbackLibraryPaths != NULL) && !context.useFallbackPaths )
+		fallbackLibraryPaths = NULL;
+	if ( !context.dontLoad  && (exceptions != NULL) && ((sEnv.DYLD_FALLBACK_FRAMEWORK_PATH != NULL) || (fallbackLibraryPaths != NULL)) ) {
+		image = loadPhase2(path, orgPath, context, sEnv.DYLD_FALLBACK_FRAMEWORK_PATH, fallbackLibraryPaths, exceptions);
 		if ( image != NULL )
 			return image;
 	}
@@ -1491,24 +2622,24 @@
 }
 
 // try root substitutions
-static ImageLoader* loadPhase0(const char* path, const LoadContext& context, std::vector<const char*>* exceptions)
-{
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
-	
+static ImageLoader* loadPhase0(const char* path, const char* orgPath, const LoadContext& context, std::vector<const char*>* exceptions)
+{
+	//dyld::log("%s(%s, %p)\n", __func__ , path, exceptions);
+
 	// handle DYLD_ROOT_PATH which forces absolute paths to use a new root
-	if ( (sEnv.DYLD_ROOT_PATH != NULL) && (path[0] == '/') ) {
-		for(const char* const* rootPath = sEnv.DYLD_ROOT_PATH ; *rootPath != NULL; ++rootPath) {
+	if ( (gLinkContext.rootPaths != NULL) && (path[0] == '/') ) {
+		for(const char* const* rootPath = gLinkContext.rootPaths ; *rootPath != NULL; ++rootPath) {
 			char newPath[strlen(*rootPath) + strlen(path)+2];
 			strcpy(newPath, *rootPath);
 			strcat(newPath, path);
-			ImageLoader* image = loadPhase1(newPath, context, exceptions);
+			ImageLoader* image = loadPhase1(newPath, orgPath, context, exceptions);
 			if ( image != NULL )
 				return image;
 		}
 	}
 
 	// try raw path
-	return loadPhase1(path, context, exceptions);
+	return loadPhase1(path, orgPath, context, exceptions);
 }
 
 //
@@ -1527,7 +2658,10 @@
 //
 ImageLoader* load(const char* path, const LoadContext& context)
 {
-	//fprintf(stderr, "%s(%s)\n", __func__ , path);
+	CRSetCrashLogMessage2(path);
+	const char* orgPath = path;
+	
+	//dyld::log("%s(%s)\n", __func__ , path);
 	char realPath[PATH_MAX];
 	// when DYLD_IMAGE_SUFFIX is in used, do a realpath(), otherwise a load of "Foo.framework/Foo" will not match
 	if ( context.useSearchPaths && ( gLinkContext.imageSuffix != NULL) ) {
@@ -1536,19 +2670,39 @@
 	}
 	
 	// try all path permutations and check against existing loaded images
-	ImageLoader* image = loadPhase0(path, context, NULL);
-	if ( image != NULL )
+	ImageLoader* image = loadPhase0(path, orgPath, context, NULL);
+	if ( image != NULL ) {
+		CRSetCrashLogMessage2(NULL);
 		return image;
-	
-	// try all path permutations and try open() until first sucesss
+	}
+
+	// try all path permutations and try open() until first success
 	std::vector<const char*> exceptions;
-	image = loadPhase0(path, context, &exceptions);
-	if ( image != NULL )
+	image = loadPhase0(path, orgPath, context, &exceptions);
+    CRSetCrashLogMessage2(NULL);
+	if ( image != NULL ) {
+		// <rdar://problem/6916014> leak in dyld during dlopen when using DYLD_ variables
+		for (std::vector<const char*>::iterator it = exceptions.begin(); it != exceptions.end(); ++it) {
+			free((void*)(*it));
+		}
+#if __IPHONE_OS_VERSION_MIN_REQUIRED
+		// if loaded image is not from cache, but original path is in cache
+		// set gSharedCacheOverridden flag to disable some ObjC optimizations
+		if ( !gSharedCacheOverridden ) {
+			if ( !image->inSharedCache() && inSharedCache(path) ) {
+				gSharedCacheOverridden = true;
+			}
+		}
+#endif
 		return image;
-	else if ( context.dontLoad )
-		return NULL;
-	else if ( exceptions.size() == 0 )
-		throw "image not found";
+	}
+	else if ( exceptions.size() == 0 ) {
+		if ( context.dontLoad ) {
+			return NULL;
+		}
+		else
+			throw "image not found";
+	}
 	else {
 		const char* msgStart = "no suitable image found.  Did find:";
 		const char* delim = "\n\t";
@@ -1560,47 +2714,492 @@
 		for (unsigned int i=0; i < exceptions.size(); ++i) {
 			strcat(fullMsg, delim);
 			strcat(fullMsg, exceptions[i]);
+			free((void*)exceptions[i]);
 		}
 		throw (const char*)fullMsg;
 	}
 }
 
+
+
+#if DYLD_SHARED_CACHE_SUPPORT
+
+
+
+#if __i386__
+	#define ARCH_NAME			"i386"
+	#define ARCH_CACHE_MAGIC	"dyld_v1    i386"
+#elif __x86_64__
+	#define ARCH_NAME			"x86_64"
+	#define ARCH_CACHE_MAGIC	"dyld_v1  x86_64"
+	#define SHARED_REGION_READ_ONLY_START   0x7FFF80000000LL
+	#define SHARED_REGION_READ_ONLY_END     0x7FFFC0000000LL
+	#define SHARED_REGION_WRITABLE_START    0x7FFF70000000LL
+	#define SHARED_REGION_WRITABLE_END      0x7FFF80000000LL
+	#define SLIDEABLE_CACHE_SUPPORT		    1
+#elif __ARM_ARCH_5TEJ__
+	#define ARCH_NAME			"armv5"
+	#define ARCH_CACHE_MAGIC	"dyld_v1   armv5"
+#elif __ARM_ARCH_6K__
+	#define ARCH_NAME			"armv6"
+	#define ARCH_CACHE_MAGIC	"dyld_v1   armv6"
+#elif __ARM_ARCH_7F__
+	#define ARCH_NAME			"armv7f"
+	#define ARCH_CACHE_MAGIC	"dyld_v1  armv7f"
+	#define SHARED_REGION_READ_ONLY_START   0x30000000
+	#define SHARED_REGION_READ_ONLY_END     0x3E000000
+	#define SHARED_REGION_WRITABLE_START    0x3E000000
+	#define SHARED_REGION_WRITABLE_END      0x40000000
+	#define SLIDEABLE_CACHE_SUPPORT		    1
+#elif __ARM_ARCH_7A__
+	#define ARCH_NAME			"armv7"
+	#define ARCH_CACHE_MAGIC	"dyld_v1   armv7"
+	#define SHARED_REGION_READ_ONLY_START   0x30000000
+	#define SHARED_REGION_READ_ONLY_END     0x3E000000
+	#define SHARED_REGION_WRITABLE_START    0x3E000000
+	#define SHARED_REGION_WRITABLE_END      0x40000000
+	#define SLIDEABLE_CACHE_SUPPORT		    1
+#elif __ARM_ARCH_7K__
+	#define ARCH_NAME			"armv7k"
+	#define ARCH_CACHE_MAGIC	"dyld_v1  armv7k"
+	#define SHARED_REGION_READ_ONLY_START   0x30000000
+	#define SHARED_REGION_READ_ONLY_END     0x3E000000
+	#define SHARED_REGION_WRITABLE_START    0x3E000000
+	#define SHARED_REGION_WRITABLE_END      0x40000000
+	#define SLIDEABLE_CACHE_SUPPORT		    1
+#endif
+
+
+static int __attribute__((noinline)) _shared_region_check_np(uint64_t* start_address)
+{
+	if ( gLinkContext.sharedRegionMode == ImageLoader::kUseSharedRegion ) 
+		return syscall(294, start_address);
+	return -1;
+}
+
+
+static int __attribute__((noinline)) _shared_region_map_and_slide_np(int fd, uint32_t count, const shared_file_mapping_np mappings[], 
+												int codeSignatureMappingIndex, int slide, void* slideInfo, uint32_t slideInfoSize)
+{
+#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+	// register code signature blob for whole dyld cache
+	if ( codeSignatureMappingIndex != -1 ) {
+		fsignatures_t siginfo;
+		siginfo.fs_file_start = 0;  // cache always starts at beginning of file
+		siginfo.fs_blob_start = (void*)mappings[codeSignatureMappingIndex].sfm_file_offset;
+		siginfo.fs_blob_size  = mappings[codeSignatureMappingIndex].sfm_size;
+		int result = fcntl(fd, F_ADDFILESIGS, &siginfo);
+		if ( result == -1 ) 
+			dyld::log("dyld: code signature for shared cache failed with errno=%d\n", errno);
+	}
+#endif
+	if ( gLinkContext.sharedRegionMode == ImageLoader::kUseSharedRegion ) {
+		return syscall(438, fd, count, mappings, slide, slideInfo, slideInfoSize);
+	}
+
+	// remove the shared region sub-map
+	vm_deallocate(mach_task_self(), (vm_address_t)SHARED_REGION_BASE, SHARED_REGION_SIZE);
+	
+	// notify gdb or other lurkers that this process is no longer using the shared region
+	dyld_all_image_infos.processDetachedFromSharedRegion = true;
+
+	// map cache just for this process with mmap()
+	const shared_file_mapping_np* const start = mappings;
+	const shared_file_mapping_np* const end = &mappings[count];
+	for (const shared_file_mapping_np* p = start; p < end; ++p ) {
+		void* mmapAddress = (void*)(uintptr_t)(p->sfm_address);
+		size_t size = p->sfm_size;
+		//dyld::log("dyld: mapping address %p with size 0x%08lX\n", mmapAddress, size);
+		int protection = 0;
+		if ( p->sfm_init_prot & VM_PROT_EXECUTE )
+			protection   |= PROT_EXEC;
+		if ( p->sfm_init_prot & VM_PROT_READ )
+			protection   |= PROT_READ;
+		if ( p->sfm_init_prot & VM_PROT_WRITE )
+			protection   |= PROT_WRITE;
+		off_t offset = p->sfm_file_offset;
+		if ( mmap(mmapAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, offset) != mmapAddress ) {
+			// failed to map some chunk of this shared cache file
+			// clear shared region
+			vm_deallocate(mach_task_self(), (vm_address_t)SHARED_REGION_BASE, SHARED_REGION_SIZE);
+			// go back to not using shared region at all
+			gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
+			if ( gLinkContext.verboseMapping ) {
+				dyld::log("dyld: shared cached region cannot be mapped at address %p with size 0x%08lX\n",
+							mmapAddress, size);
+			}
+			// return failure
+			return -1;
+		}
+	}
+
+#if SLIDEABLE_CACHE_SUPPORT
+	// update all __DATA pages with slide info
+	if ( slide != 0 ) {
+		const uintptr_t dataPagesStart = mappings[1].sfm_address;
+		const dyld_cache_slide_info* slideInfoHeader = (dyld_cache_slide_info*)slideInfo;
+		const uint16_t* toc = (uint16_t*)((long)(slideInfoHeader) + slideInfoHeader->toc_offset);
+		const uint8_t* entries = (uint8_t*)((long)(slideInfoHeader) + slideInfoHeader->entries_offset);
+		for(uint32_t i=0; i < slideInfoHeader->toc_count; ++i) {
+			const uint8_t* entry = &entries[toc[i]*slideInfoHeader->entries_size];
+			const uint8_t* page = (uint8_t*)(long)(dataPagesStart + (4096*i));
+			//dyld::log("page=%p toc[%d]=%d entries=%p\n", page, i, toc[i], entry);
+			for(int j=0; j < 128; ++j) {
+				uint8_t b = entry[j];
+				//dyld::log("    entry[%d] = 0x%02X\n", j, b);
+				if ( b != 0 ) {
+					for(int k=0; k < 8; ++k) {
+						if ( b & (1<<k) ) {
+							uintptr_t* p = (uintptr_t*)(page + j*8*4 + k*4);
+							uintptr_t value = *p;
+							//dyld::log("        *%p was 0x%lX will be 0x%lX\n", p, value, value+sSharedCacheSlide);
+							*p = value + slide;
+						}
+					}
+				}
+			}
+		}
+	}
+#endif // SLIDEABLE_CACHE_SUPPORT
+
+	// succesfully mapped shared cache for just this process
+	gLinkContext.sharedRegionMode = ImageLoader::kUsePrivateSharedRegion;
+	
+	return 0;
+}
+
+
+const void*	imMemorySharedCacheHeader()
+{
+	return sSharedCache;
+}
+
+int openSharedCacheFile()
+{
+	char path[1024];
+	strcpy(path, sSharedCacheDir);
+	strcat(path, "/");
+	strcat(path, DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME);
+	return ::open(path, O_RDONLY);
+}
+
+#if SLIDEABLE_CACHE_SUPPORT
+static long pickCacheSlide(uint32_t mappingsCount, shared_file_mapping_np mappings[])
+{
+	// get bounds of cache
+	uint64_t readOnlyLowAddress = 0;
+	uint64_t readOnlyHighAddress = 0;
+	uint64_t writableLowAddress = 0;
+	uint64_t writableHighAddress = 0;
+	for(uint32_t i=0; i < mappingsCount; ++i) {
+		if ( mappings[i].sfm_init_prot & VM_PROT_WRITE ) {
+			writableLowAddress = mappings[i].sfm_address;
+			writableHighAddress = mappings[i].sfm_address + mappings[i].sfm_size;
+		}
+		else {
+			if ( readOnlyLowAddress == 0 ) {
+				readOnlyLowAddress = mappings[i].sfm_address;
+				readOnlyHighAddress = mappings[i].sfm_address + mappings[i].sfm_size;
+			}
+			else {
+				if ( readOnlyLowAddress < mappings[i].sfm_address ) {
+					readOnlyHighAddress = mappings[i].sfm_address + mappings[i].sfm_size;
+				}
+				else {
+					readOnlyLowAddress = mappings[i].sfm_address;
+				}
+			}
+		}
+	}
+	
+	// find read-only slop space
+	uint64_t roSpace = SHARED_REGION_READ_ONLY_END - readOnlyHighAddress;
+
+	// find writable slop space
+	uint64_t rwSpace = SHARED_REGION_WRITABLE_END - writableHighAddress;
+	
+	// choose new random slide
+	long slideSpace = (roSpace > rwSpace) ? rwSpace : roSpace;
+	long slide = (arc4random() % slideSpace) & (-4096);
+	//dyld::log("roSpace=0x%0llX\n", roSpace);
+	//dyld::log("rwSpace=0x%0llX\n", rwSpace);
+	//dyld::log("slideSpace=0x%0lX\n", slideSpace);
+	//dyld::log("slide=0x%0lX\n", slide);
+	
+	// update mappings
+	for(uint32_t i=0; i < mappingsCount; ++i) {
+		mappings[i].sfm_address += slide;
+	}
+	
+	return slide;
+}
+#endif // SLIDEABLE_CACHE_SUPPORT
+
+static void mapSharedCache()
+{
+	uint64_t cacheBaseAddress;
+	// quick check if a cache is alreay mapped into shared region
+	if ( _shared_region_check_np(&cacheBaseAddress) == 0 ) {
+		sSharedCache = (dyld_cache_header*)cacheBaseAddress;
+		// if we don't understand the currently mapped shared cache, then ignore
+		if ( strcmp(sSharedCache->magic, ARCH_CACHE_MAGIC) != 0 ) {
+			sSharedCache = NULL;
+			if ( gLinkContext.verboseMapping ) 
+				dyld::log("dyld: existing shared cached in memory is not compatible\n");
+		}
+		// check if cache file is slidable
+		dyld_cache_header* header = (dyld_cache_header*)sSharedCache;
+		if ( (header->mappingOffset >= 0x48) && (header->slideInfoSize != 0) ) {
+			// solve for slide by comparing loaded address to address of first region
+			const uint8_t* loadedAddress = (uint8_t*)sSharedCache;
+			const dyld_cache_mapping_info* const mappings = (dyld_cache_mapping_info*)(loadedAddress+header->mappingOffset);
+			const uint8_t* preferedLoadAddress = (uint8_t*)(long)(mappings[0].address);
+			sSharedCacheSlide = loadedAddress - preferedLoadAddress;
+			dyld_all_image_infos.sharedCacheSlide = sSharedCacheSlide;
+			//dyld::log("sSharedCacheSlide=0x%08lX, loadedAddress=%p, preferedLoadAddress=%p\n", sSharedCacheSlide, loadedAddress, preferedLoadAddress);
+		}
+	}
+	else {
+#if __i386__ || __x86_64__
+		// <rdar://problem/5925940> Safe Boot should disable dyld shared cache
+		// if we are in safe-boot mode and the cache was not made during this boot cycle,
+		// delete the cache file
+		uint32_t	safeBootValue = 0;
+		size_t		safeBootValueSize = sizeof(safeBootValue);
+		if ( (sysctlbyname("kern.safeboot", &safeBootValue, &safeBootValueSize, NULL, 0) == 0) && (safeBootValue != 0) ) {
+			// user booted machine in safe-boot mode
+			struct stat dyldCacheStatInfo;
+			//  Don't use custom DYLD_SHARED_CACHE_DIR if provided, use standard path
+			if ( ::stat(MACOSX_DYLD_SHARED_CACHE_DIR DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME, &dyldCacheStatInfo) == 0 ) {
+				struct timeval bootTimeValue;
+				size_t bootTimeValueSize = sizeof(bootTimeValue);
+				if ( (sysctlbyname("kern.boottime", &bootTimeValue, &bootTimeValueSize, NULL, 0) == 0) && (bootTimeValue.tv_sec != 0) ) {
+					// if the cache file was created before this boot, then throw it away and let it rebuild itself
+					if ( dyldCacheStatInfo.st_mtime < bootTimeValue.tv_sec ) {
+						::unlink(MACOSX_DYLD_SHARED_CACHE_DIR DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME);
+						gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
+						return;
+					}
+				}
+			}
+		}
+#endif
+		// map in shared cache to shared region
+		int fd = openSharedCacheFile();
+		if ( fd != -1 ) {
+			uint8_t firstPages[8192];
+			if ( ::read(fd, firstPages, 8192) == 8192 ) {
+				dyld_cache_header* header = (dyld_cache_header*)firstPages;
+				if ( strcmp(header->magic, ARCH_CACHE_MAGIC) == 0 ) {
+					const dyld_cache_mapping_info* const fileMappingsStart = (dyld_cache_mapping_info*)&firstPages[header->mappingOffset];
+					const dyld_cache_mapping_info* const fileMappingsEnd = &fileMappingsStart[header->mappingCount];
+					shared_file_mapping_np	mappings[header->mappingCount+1]; // add room for code-sig 
+					unsigned int mappingCount = header->mappingCount;
+					int codeSignatureMappingIndex = -1;
+					// validate that the cache file has not been truncated
+					bool goodCache = false;
+					struct stat stat_buf;
+					if ( fstat(fd, &stat_buf) == 0 ) {
+						goodCache = true;
+						int i=0;
+						for (const dyld_cache_mapping_info* p = fileMappingsStart; p < fileMappingsEnd; ++p, ++i) {
+							mappings[i].sfm_address		= p->address;
+							mappings[i].sfm_size		= p->size;
+							mappings[i].sfm_file_offset	= p->fileOffset;
+							mappings[i].sfm_max_prot	= p->maxProt;
+							mappings[i].sfm_init_prot	= p->initProt;
+							// rdar://problem/5694507 old update_dyld_shared_cache tool could make a cache file
+							// that is not page aligned, but otherwise ok.
+							if ( p->fileOffset+p->size > (uint64_t)(stat_buf.st_size+4095 & (-4096)) ) {
+								dyld::log("dyld: shared cached file is corrupt: %s" DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME "\n", sSharedCacheDir);
+								goodCache = false;
+							}
+						}
+#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+						// if shared cache is code signed, add a mapping for the code signature
+						uint32_t signatureSize = header->codeSignatureSize;
+						// zero size in header means signature runs to end-of-file
+						if ( signatureSize == 0 )
+							signatureSize = stat_buf.st_size - header->codeSignatureOffset;
+						if ( signatureSize != 0 ) {
+                            int linkeditMapping = mappingCount-1;
+							codeSignatureMappingIndex = mappingCount++;
+							mappings[codeSignatureMappingIndex].sfm_address		= mappings[linkeditMapping].sfm_address + mappings[linkeditMapping].sfm_size;
+							mappings[codeSignatureMappingIndex].sfm_size		= (signatureSize+4095) & (-4096);
+							mappings[codeSignatureMappingIndex].sfm_file_offset	= header->codeSignatureOffset;
+							mappings[codeSignatureMappingIndex].sfm_max_prot	= VM_PROT_READ;
+							mappings[codeSignatureMappingIndex].sfm_init_prot	= VM_PROT_READ;
+						}
+#endif
+					}
+#if __MAC_OS_X_VERSION_MIN_REQUIRED	
+					// sanity check that /usr/lib/libSystem.B.dylib stat() info matches cache
+					if ( header->imagesCount * sizeof(dyld_cache_image_info) + header->imagesOffset < 8192 ) {
+						bool foundLibSystem = false;
+						if ( stat("/usr/lib/libSystem.B.dylib", &stat_buf) == 0 ) {
+							const dyld_cache_image_info* images = (dyld_cache_image_info*)&firstPages[header->imagesOffset];
+							const dyld_cache_image_info* const imagesEnd = &images[header->imagesCount];
+							for (const dyld_cache_image_info* p = images; p < imagesEnd; ++p) {
+ 								if ( ((time_t)p->modTime == stat_buf.st_mtime) && ((ino_t)p->inode == stat_buf.st_ino) ) {
+									foundLibSystem = true;
+									break;
+								}
+							}					
+						}
+						if ( !sSharedCacheIgnoreInodeAndTimeStamp && !foundLibSystem ) {
+							dyld::log("dyld: shared cached file was built against a different libSystem.dylib, ignoring cache.\n"
+									"to update dyld shared cache run: 'sudo update_dyld_shared_cache' then reboot.\n");
+							goodCache = false;
+						}
+					}
+#endif										
+					if ( goodCache ) {
+						long cacheSlide = 0;
+						void* slideInfo = NULL;
+						uint32_t slideInfoSize = 0;
+					#if SLIDEABLE_CACHE_SUPPORT
+						// check if shared cache contains slid info
+						if ( header->slideInfoSize != 0 ) {
+							// <rdar://problem/8611968> don't slide shared cache if ASLR disabled (main executable didn't slide)
+							if ( sMainExecutable->isPositionIndependentExecutable() && (sMainExecutable->getSlide() == 0) )
+								cacheSlide = 0;
+							else {
+								// generate random slide amount
+								cacheSlide = pickCacheSlide(mappingCount, mappings);
+								slideInfo = (void*)(long)(mappings[2].sfm_address + (header->slideInfoOffset - mappings[2].sfm_file_offset));
+								slideInfoSize = header->slideInfoSize;
+								// add VM_PROT_SLIDE bit to __DATA area of cache
+								mappings[1].sfm_max_prot  |= VM_PROT_SLIDE;
+								mappings[1].sfm_init_prot |= VM_PROT_SLIDE;
+							}
+						}
+					#endif
+						if (_shared_region_map_and_slide_np(fd, mappingCount, mappings, codeSignatureMappingIndex, cacheSlide, slideInfo, slideInfoSize) == 0) {
+							// successfully mapped cache into shared region
+							sSharedCache = (dyld_cache_header*)mappings[0].sfm_address;
+							sSharedCacheSlide = cacheSlide;
+							dyld_all_image_infos.sharedCacheSlide = cacheSlide;
+							//dyld::log("sSharedCache=%p sSharedCacheSlide=0x%08lX\n", sSharedCache, sSharedCacheSlide);
+						}
+						else {
+							if ( gLinkContext.verboseMapping ) 
+								dyld::log("dyld: shared cached file could not be mapped\n");
+						}
+					}
+				}
+				else {
+					if ( gLinkContext.verboseMapping ) 
+						dyld::log("dyld: shared cached file is invalid\n");
+				}
+			}
+			else {
+				if ( gLinkContext.verboseMapping ) 
+					dyld::log("dyld: shared cached file cannot be read\n");
+			}
+			close(fd);
+		}
+		else {
+			if ( gLinkContext.verboseMapping ) 
+				dyld::log("dyld: shared cached file cannot be opened\n");
+		}
+	}
+	
+	// remember if dyld loaded at same address as when cache built
+	if ( sSharedCache != NULL ) {
+		gLinkContext.dyldLoadedAtSameAddressNeededBySharedCache = ((uintptr_t)(sSharedCache->dyldBaseAddress) == (uintptr_t)&_mh_dylinker_header);
+	}
+	
+	// tell gdb where the shared cache is
+	if ( sSharedCache != NULL ) {
+		const dyld_cache_mapping_info* const start = (dyld_cache_mapping_info*)((uint8_t*)sSharedCache + sSharedCache->mappingOffset);
+		dyld_shared_cache_ranges.sharedRegionsCount = sSharedCache->mappingCount;
+		// only room to tell gdb about first four regions
+		if ( dyld_shared_cache_ranges.sharedRegionsCount > 4 )
+			dyld_shared_cache_ranges.sharedRegionsCount = 4;
+		if ( gLinkContext.verboseMapping ) {
+			if ( gLinkContext.sharedRegionMode == ImageLoader::kUseSharedRegion )
+				dyld::log("dyld: Mapping shared cache from %s/" DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME "\n", sSharedCacheDir);
+			else if ( gLinkContext.sharedRegionMode == ImageLoader::kUsePrivateSharedRegion )
+				dyld::log("dyld: Mapping private shared cache from %s/" DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME "\n", sSharedCacheDir);
+		}
+		const dyld_cache_mapping_info* const end = &start[dyld_shared_cache_ranges.sharedRegionsCount];
+		int index = 0;
+		for (const dyld_cache_mapping_info* p = start; p < end; ++p, ++index ) {
+			dyld_shared_cache_ranges.ranges[index].start = p->address+sSharedCacheSlide;
+			dyld_shared_cache_ranges.ranges[index].length = p->size;
+			if ( gLinkContext.verboseMapping ) {
+				dyld::log("        0x%08llX->0x%08llX %s%s%s init=%x, max=%x\n", 
+					p->address+sSharedCacheSlide, p->address+sSharedCacheSlide+p->size-1,
+					((p->initProt & VM_PROT_READ) ? "read " : ""),
+					((p->initProt & VM_PROT_WRITE) ? "write " : ""),
+					((p->initProt & VM_PROT_EXECUTE) ? "execute " : ""),  p->initProt, p->maxProt);
+			}
+		#if __i386__
+			// If a non-writable and executable region is found in the R/W shared region, then this is __IMPORT segments
+			// This is an old cache.  Make writable.  dyld no longer supports turn W on and off as it binds
+			if ( (p->initProt == (VM_PROT_READ|VM_PROT_EXECUTE)) && ((p->address & 0xF0000000) == 0xA0000000) ) {
+				if ( p->size != 0 ) {
+					vm_prot_t prot = VM_PROT_EXECUTE | PROT_READ | VM_PROT_WRITE;
+					vm_protect(mach_task_self(), p->address, p->size, false, prot);
+					if ( gLinkContext.verboseMapping ) {
+						dyld::log("%18s at 0x%08llX->0x%08llX altered permissions to %c%c%c\n", "", p->address, 
+							p->address+p->size-1,
+							(prot & PROT_READ) ? 'r' : '.',  (prot & PROT_WRITE) ? 'w' : '.',  (prot & PROT_EXEC) ? 'x' : '.' );
+					}
+				}
+			}
+		#endif
+		}
+#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+		if ( gLinkContext.verboseMapping ) {
+			// list the code blob
+			dyld_cache_header* header = (dyld_cache_header*)sSharedCache;
+			uint32_t signatureSize = header->codeSignatureSize;
+			// zero size in header means signature runs to end-of-file
+			if ( signatureSize == 0 ) {
+				struct stat stat_buf;
+				if ( ::stat(IPHONE_DYLD_SHARED_CACHE_DIR DYLD_SHARED_CACHE_BASE_NAME ARCH_NAME, &stat_buf) == 0 ) 
+					signatureSize = stat_buf.st_size - header->codeSignatureOffset;
+			}
+			if ( signatureSize != 0 ) {
+				const dyld_cache_mapping_info* const last = &start[dyld_shared_cache_ranges.sharedRegionsCount-1];
+				uint64_t codeBlobStart = last->address + last->size;
+				dyld::log("        0x%08llX->0x%08llX (code signature)\n", codeBlobStart, codeBlobStart+signatureSize);
+			}
+		}
+		// check for file that enables dyld shared cache dylibs to be overridden
+		struct stat enableStatBuf;
+		sDylibsOverrideCache = ( ::stat(IPHONE_DYLD_SHARED_CACHE_DIR "enable-dylibs-to-override-cache", &enableStatBuf) == 0 );
+#endif	
+	}
+}
+#endif // #if DYLD_SHARED_CACHE_SUPPORT
 
 
 
 // create when NSLinkModule is called for a second time on a bundle
 ImageLoader* cloneImage(ImageLoader* image)
 {
-	const uint64_t offsetInFat = image->getOffsetInFatFile();
-
 	// open file (automagically closed when this function exits)
 	FileOpener file(image->getPath());
 	
 	struct stat stat_buf;
-#if __ppc64__
-	memset(&stat_buf, 254, sizeof(struct stat));	 // hack until rdar://problem/3845883 is fixed
-#endif
 	if ( fstat(file.getFileDescriptor(), &stat_buf) == -1)
 		throw "stat error";
 	
-	// read first page of file
-	uint8_t firstPage[4096];
-	pread(file.getFileDescriptor(), firstPage, 4096, offsetInFat);
-	
-	// fat length is only used for sanity checking, since this image was already loaded once, just use upper bound
-	uint64_t lenInFat = stat_buf.st_size - offsetInFat;
-	
-	// try mach-o loader
-	if ( isCompatibleMachO(firstPage) ) {
-		ImageLoader* clone = new ImageLoaderMachO(image->getPath(), file.getFileDescriptor(), firstPage, offsetInFat, lenInFat, stat_buf, gLinkContext);
-		// don't add bundles to global list, they can be loaded but not linked.  When linked it will be added to list
-		if ( ! image->isBundle() ) 
-			addImage(clone);
-		return clone;
-	}
-	
-	// try other file formats...
-	throw "can't clone image";
+	dyld::LoadContext context;
+	context.useSearchPaths		= false;
+	context.useFallbackPaths	= false;
+	context.useLdLibraryPath	= false;
+	context.implicitRPath		= false;
+	context.matchByInstallName	= false;
+	context.dontLoad			= false;
+	context.mustBeBundle		= true;
+	context.mustBeDylib			= false;
+	context.canBePIE			= false;
+	context.origin				= NULL;
+	context.rpath				= NULL;
+	return loadPhase6(file.getFileDescriptor(), stat_buf, image->getPath(), context);
 }
 
 
@@ -1620,16 +3219,16 @@
 		}
 	}
 
-	// try mach-o each loader
-	if ( isCompatibleMachO(mem) ) {
-		ImageLoader* image = new ImageLoaderMachO(moduleName, (mach_header*)mem, len, gLinkContext);
+	// try each loader
+	if ( isCompatibleMachO(mem, moduleName) ) {
+		ImageLoader* image = ImageLoaderMachO::instantiateFromMemory(moduleName, (macho_header*)mem, len, gLinkContext);
 		// don't add bundles to global list, they can be loaded but not linked.  When linked it will be added to list
 		if ( ! image->isBundle() ) 
 			addImage(image);
 		return image;
 	}
 	
-	// try other file formats...
+	// try other file formats here...
 	
 	// throw error about what was found
 	switch (*(uint32_t*)mem) {
@@ -1650,17 +3249,12 @@
 	// now add to list to get notified when any more images are added
 	sAddImageCallbacks.push_back(func);
 	
-	// call callback with all existing images, starting at roots
-	const int rootCount = sImageRoots.size();
-	for(int i=0; i < rootCount; ++i) {
-		ImageLoader* image = sImageRoots[i];
-		image->runNotification(gLinkContext, sAddImageCallbacks.size());
-	}
-	
-//	for (std::vector<ImageLoader*>::iterator it=sImageRoots.begin(); it != sImageRoots.end(); it++) {
-//		ImageLoader* image = *it;
-//		image->runNotification(gLinkContext, sAddImageCallbacks.size());
-//	}
+	// call callback with all existing images
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+		ImageLoader* image = *it;
+		if ( image->getState() >= dyld_image_state_bound && image->getState() < dyld_image_state_terminated )
+			(*func)(image->machHeader(), image->getSlide());
+	}
 }
 
 void registerRemoveCallback(ImageCallback func)
@@ -1676,8 +3270,7 @@
 void setErrorMessage(const char* message)
 {
 	// save off error message in global buffer for CrashReporter to find
-	strncpy(error_string, message, sizeof(error_string)-1);
-	error_string[sizeof(error_string)-1] = '\0';
+	strlcpy(error_string, message, sizeof(error_string));
 }
 
 const char* getErrorMessage()
@@ -1685,21 +3278,25 @@
 	return error_string;
 }
 
-void  halt(const char* message)
-{
-	fprintf(stderr, "dyld: %s\n", message);
+
+void halt(const char* message)
+{
+	dyld::log("dyld: %s\n", message);
 	setErrorMessage(message);
-	strncpy(error_string, message, sizeof(error_string)-1);
-	error_string[sizeof(error_string)-1] = '\0';
-	
-#if __ppc__ || __ppc64__
-	__asm__  ("trap");
-#elif __i386__
-	__asm__  ("int3");
-#else
-	#error unknown architecture
-#endif
-	abort();	// needed to suppress warning that noreturn function returns
+	uintptr_t terminationFlags = 0;
+	if ( !gLinkContext.startedInitializingMainExecutable ) 
+		terminationFlags = 1;
+	setAlImageInfosHalt(error_string, terminationFlags);
+	dyld_fatal_error(error_string);
+}
+
+static void setErrorStrings(unsigned errorCode, const char* errorClientOfDylibPath,
+								const char* errorTargetDylibPath, const char* errorSymbol)
+{
+	dyld_all_image_infos.errorKind = errorCode;
+	dyld_all_image_infos.errorClientOfDylibPath = errorClientOfDylibPath;
+	dyld_all_image_infos.errorTargetDylibPath = errorTargetDylibPath;
+	dyld_all_image_infos.errorSymbol = errorSymbol;
 }
 
 
@@ -1708,8 +3305,8 @@
 	uintptr_t result = 0;
 	// acquire read-lock on dyld's data structures
 #if 0 // rdar://problem/3811777 turn off locking until deadlock is resolved
-	if ( gThreadHelpers != NULL ) 
-		(*gThreadHelpers->lockForReading)();
+	if ( gLibSystemHelpers != NULL ) 
+		(*gLibSystemHelpers->lockForReading)();
 #endif
 	// lookup and bind lazy pointer and get target address
 	try {
@@ -1717,7 +3314,7 @@
 	#if __i386__
 		// fast stubs pass NULL for mh and image is instead found via the location of stub (aka lazyPointer)
 		if ( mh == NULL )
-			target = dyld::findImageContainingAddressThreadSafe(lazyPointer);
+			target = dyld::findImageContainingAddress(lazyPointer);
 		else
 			target = dyld::findImageByMachHeader(mh);
 	#else
@@ -1725,29 +3322,53 @@
 		target = dyld::findImageByMachHeader(mh);
 	#endif
 		if ( target == NULL )
-			throw "image not found for lazy pointer";
+			throwf("image not found for lazy pointer at %p", lazyPointer);
 		result = target->doBindLazySymbol(lazyPointer, gLinkContext);
 	}
 	catch (const char* message) {
-		fprintf(stderr, "dyld: lazy symbol binding failed: %s\n", message);
+		dyld::log("dyld: lazy symbol binding failed: %s\n", message);
 		halt(message);
 	}
 	// release read-lock on dyld's data structures
 #if 0
-	if ( gThreadHelpers != NULL ) 
-		(*gThreadHelpers->unlockForReading)();
+	if ( gLibSystemHelpers != NULL ) 
+		(*gLibSystemHelpers->unlockForReading)();
 #endif
 	// return target address to glue which jumps to it with real parameters restored
 	return result;
 }
 
 
-// SPI used by ZeroLink to lazy load bundles
-void registerZeroLinkHandlers(BundleNotificationCallBack notify, BundleLocatorCallBack locate)
-{
-	sBundleNotifier = notify;
-	sBundleLocation = locate;
-}
+uintptr_t fastBindLazySymbol(ImageLoader** imageLoaderCache, uintptr_t lazyBindingInfoOffset)
+{
+	uintptr_t result = 0;
+	// get image 
+	if ( *imageLoaderCache == NULL ) {
+		// save in cache
+		*imageLoaderCache = dyld::findMappedRange((uintptr_t)imageLoaderCache);
+		if ( *imageLoaderCache == NULL ) {
+			const char* message = "fast lazy binding from unknown image";
+			dyld::log("dyld: %s\n", message);
+			halt(message);
+		}
+	}
+	
+	// bind lazy pointer and return it
+	try {
+		result = (*imageLoaderCache)->doBindFastLazySymbol(lazyBindingInfoOffset, gLinkContext, 
+								(dyld::gLibSystemHelpers != NULL) ? dyld::gLibSystemHelpers->acquireGlobalDyldLock : NULL,
+								(dyld::gLibSystemHelpers != NULL) ? dyld::gLibSystemHelpers->releaseGlobalDyldLock : NULL);
+	}
+	catch (const char* message) {
+		dyld::log("dyld: lazy symbol binding failed: %s\n", message);
+		halt(message);
+	}
+
+	// return target address to glue which jumps to it with real parameters restored
+	return result;
+}
+
+
 
 void registerUndefinedHandler(UndefinedHandler handler)
 {
@@ -1761,53 +3382,24 @@
 	}
 }
 
-static bool findExportedSymbol(const char* name, bool onlyInCoalesced, const ImageLoader::Symbol** sym, ImageLoader** image)
-{
-	// try ZeroLink short cut to finding bundle which exports this symbol
-	if ( sBundleLocation != NULL ) {
-		ImageLoader* zlImage = (*sBundleLocation)(name);
-		if ( zlImage == ((ImageLoader*)(-1)) ) {
-			// -1 is magic value that request symbol is in a bundle not yet linked into process
-			// try calling handler to link in that symbol
-			undefinedHandler(name);
-			// call locator again
-			zlImage = (*sBundleLocation)(name);
-		}
-		// if still not found, then ZeroLink has no idea where to find it
-		if ( zlImage == ((ImageLoader*)(-1)) ) 
-			return false;
-		if ( zlImage != NULL ) {
-			// ZeroLink cache knows where the symbol is
-			*sym = zlImage->findExportedSymbol(name, NULL, false, image);
-			if ( *sym != NULL ) {
-				*image = zlImage;
-				return true;
-			}
-		}
-		else {
-			// ZeroLink says it is in some bundle already loaded, but not linked, walk them all
-			const unsigned int imageCount = sAllImages.size();
-			for(unsigned int i=0; i < imageCount; ++i){
-				ImageLoader* anImage = sAllImages[i];
-				if ( anImage->isBundle() && !anImage->hasHiddenExports() ) {
-					//fprintf(stderr, "dyld: search for %s in %s\n", name, anImage->getPath());
-					*sym = anImage->findExportedSymbol(name, NULL, false, image);
-					if ( *sym != NULL ) {
-						return true;
-					}
-				}
-			}
-		}
-	}
-
+static bool findExportedSymbol(const char* name, bool onlyInCoalesced, const ImageLoader::Symbol** sym, const ImageLoader** image)
+{
 	// search all images in order
-	ImageLoader* firstWeakImage = NULL;
+	const ImageLoader* firstWeakImage = NULL;
 	const ImageLoader::Symbol* firstWeakSym = NULL;
 	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i){
+	for(unsigned int i=0; i < imageCount; ++i) {
 		ImageLoader* anImage = sAllImages[i];
+		// the use of inserted libraries alters search order
+		// so that inserted libraries are found before the main executable
+		if ( sInsertedDylibCount > 0 ) {
+			if ( i < sInsertedDylibCount )
+				anImage = sAllImages[i+1];
+			else if ( i == sInsertedDylibCount )
+				anImage = sAllImages[0];
+		}
 		if ( ! anImage->hasHiddenExports() && (!onlyInCoalesced || anImage->hasCoalescedExports()) ) {
-			*sym = anImage->findExportedSymbol(name, NULL, false, image);
+			*sym = anImage->findExportedSymbol(name, false, image);
 			if ( *sym != NULL ) {
 				// if weak definition found, record first one found
 				if ( ((*image)->getExportedSymbolInfo(*sym) & ImageLoader::kWeakDefinition) != 0 ) {
@@ -1833,18 +3425,18 @@
 	return false;
 }
 
-bool flatFindExportedSymbol(const char* name, const ImageLoader::Symbol** sym, ImageLoader** image)
+bool flatFindExportedSymbol(const char* name, const ImageLoader::Symbol** sym, const ImageLoader** image)
 {
 	return findExportedSymbol(name, false, sym, image);
 }
 
-bool findCoalescedExportedSymbol(const char* name, const ImageLoader::Symbol** sym, ImageLoader** image)
+bool findCoalescedExportedSymbol(const char* name, const ImageLoader::Symbol** sym, const ImageLoader** image)
 {
 	return findExportedSymbol(name, true, sym, image);
 }
 
 
-bool flatFindExportedSymbolWithHint(const char* name, const char* librarySubstring, const ImageLoader::Symbol** sym, ImageLoader** image)
+bool flatFindExportedSymbolWithHint(const char* name, const char* librarySubstring, const ImageLoader::Symbol** sym, const ImageLoader** image)
 {
 	// search all images in order
 	const unsigned int imageCount = sAllImages.size();
@@ -1852,7 +3444,7 @@
 		ImageLoader* anImage = sAllImages[i];
 		// only look at images whose paths contain the hint string (NULL hint string is wildcard)
 		if ( ! anImage->isBundle() && ((librarySubstring==NULL) || (strstr(anImage->getPath(), librarySubstring) != NULL)) ) {
-			*sym = anImage->findExportedSymbol(name, NULL, false, image);
+			*sym = anImage->findExportedSymbol(name, false, image);
 			if ( *sym != NULL ) {
 				return true;
 			}
@@ -1861,114 +3453,445 @@
 	return false;
 }
 
-static void getMappedRegions(ImageLoader::RegionsVector& regions)
-{
-	const unsigned int imageCount = sAllImages.size();
-	for(unsigned int i=0; i < imageCount; ++i){
-		ImageLoader* anImage = sAllImages[i];
-		anImage->addMappedRegions(regions);
-	}
-}
-
-
-static ImageLoader* libraryLocator(const char* libraryName, bool search, const char* origin, const char* rpath[])
+unsigned int getCoalescedImages(ImageLoader* images[])
+{
+	unsigned int count = 0;
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+		ImageLoader* image = *it;
+		if ( image->participatesInCoalescing() ) {
+			*images++ = *it;
+			++count;
+		}
+	}
+	return count;
+}
+
+
+static ImageLoader::MappedRegion* getMappedRegions(ImageLoader::MappedRegion* regions)
+{
+	ImageLoader::MappedRegion* end = regions;
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+		(*it)->getMappedRegions(end);
+	}
+	return end;
+}
+
+void registerImageStateSingleChangeHandler(dyld_image_states state, dyld_image_state_change_handler handler)
+{
+	// mark the image that the handler is in as never-unload because dyld has a reference into it
+	ImageLoader* handlerImage = findImageContainingAddress((void*)handler);
+	if ( handlerImage != NULL )
+		handlerImage->setNeverUnload();
+
+	// add to list of handlers
+	std::vector<dyld_image_state_change_handler>* handlers = stateToHandlers(state, sSingleHandlers);
+	if ( handlers != NULL ) {
+        // <rdar://problem/10332417> need updateAllImages() to be last in dyld_image_state_mapped list
+        // so that if ObjC adds a handler that prevents a load, it happens before the gdb list is updated
+        if ( state == dyld_image_state_mapped )
+            handlers->insert(handlers->begin(), handler);
+        else
+            handlers->push_back(handler);
+
+		// call callback with all existing images
+		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+			ImageLoader* image = *it;
+			dyld_image_info	 info;
+			info.imageLoadAddress	= image->machHeader();
+			info.imageFilePath		= image->getRealPath();
+			info.imageFileModDate	= image->lastModified();
+			// should only call handler if state == image->state
+			if ( image->getState() == state )
+				(*handler)(state, 1, &info);
+			// ignore returned string, too late to do anything
+		}
+	}
+}
+
+void registerImageStateBatchChangeHandler(dyld_image_states state, dyld_image_state_change_handler handler)
+{
+	// mark the image that the handler is in as never-unload because dyld has a reference into it
+	ImageLoader* handlerImage = findImageContainingAddress((void*)handler);
+	if ( handlerImage != NULL )
+		handlerImage->setNeverUnload();
+
+	// add to list of handlers
+	std::vector<dyld_image_state_change_handler>* handlers = stateToHandlers(state, sBatchHandlers);
+	if ( handlers != NULL ) {
+		// insert at front, so that gdb handler is always last
+		handlers->insert(handlers->begin(), handler);
+		
+		// call callback with all existing images
+		try {
+			notifyBatchPartial(state, true, handler);
+		}
+		catch (const char* msg) {
+			// ignore request to abort during registration
+		}
+	}
+}
+
+static ImageLoader* libraryLocator(const char* libraryName, bool search, const char* origin, const ImageLoader::RPathChain* rpaths)
 {
 	dyld::LoadContext context;
 	context.useSearchPaths		= search;
+	context.useFallbackPaths	= search;
 	context.useLdLibraryPath	= false;
+	context.implicitRPath		= false;
+	context.matchByInstallName	= false;
 	context.dontLoad			= false;
 	context.mustBeBundle		= false;
 	context.mustBeDylib			= true;
-	context.matchByInstallName	= false;
+	context.canBePIE			= false;
 	context.origin				= origin;
-	context.rpath				= rpath;
+	context.rpath				= rpaths;
 	return load(libraryName, context);
 }
 
-	
-static void setContext(int argc, const char* argv[], const char* envp[], const char* apple[])
+static const char* basename(const char* path)
+{
+    const char* last = path;
+    for (const char* s = path; *s != '\0'; s++) {
+        if (*s == '/') 
+			last = s+1;
+    }
+    return last;
+}
+
+static void setContext(const macho_header* mainExecutableMH, int argc, const char* argv[], const char* envp[], const char* apple[])
 {
 	gLinkContext.loadLibrary			= &libraryLocator;
-	gLinkContext.imageNotification		= &imageNotification;
 	gLinkContext.terminationRecorder	= &terminationRecorder;
 	gLinkContext.flatExportFinder		= &flatFindExportedSymbol;
 	gLinkContext.coalescedExportFinder	= &findCoalescedExportedSymbol;
+	gLinkContext.getCoalescedImages		= &getCoalescedImages;
 	gLinkContext.undefinedHandler		= &undefinedHandler;
-	gLinkContext.addImageNeedingNotification = &addImageNeedingNotification;
-	gLinkContext.notifyAdding			= &notifyAdding;
 	gLinkContext.getAllMappedRegions	= &getMappedRegions;
 	gLinkContext.bindingHandler			= NULL;
+	gLinkContext.notifySingle			= &notifySingle;
+	gLinkContext.notifyBatch			= &notifyBatch;
+	gLinkContext.removeImage			= &removeImage;
+	gLinkContext.registerDOFs			= &registerDOFs;
+	gLinkContext.clearAllDepths			= &clearAllDepths;
+	gLinkContext.printAllDepths			= &printAllDepths;
+	gLinkContext.imageCount				= &imageCount;
+	gLinkContext.setNewProgramVars		= &setNewProgramVars;
+#if DYLD_SHARED_CACHE_SUPPORT
+	gLinkContext.inSharedCache			= &inSharedCache;
+#endif
+	gLinkContext.setErrorStrings		= &setErrorStrings;
+#if SUPPORT_OLD_CRT_INITIALIZATION
+	gLinkContext.setRunInitialzersOldWay= &setRunInitialzersOldWay;
+#endif
 	gLinkContext.bindingOptions			= ImageLoader::kBindingNone;
-	gLinkContext.mainExecutable			= sMainExecutable;
 	gLinkContext.argc					= argc;
 	gLinkContext.argv					= argv;
 	gLinkContext.envp					= envp;
 	gLinkContext.apple					= apple;
-}
-
-static bool checkEmulation()
-{
-#if __i386__
-	int mib[] = { CTL_KERN, KERN_CLASSIC, getpid() };
-	int is_classic = 0;
-	size_t len = sizeof(int);
-	int ret = sysctl(mib, 3, &is_classic, &len, NULL, 0);
-	if ((ret != -1) && is_classic) {
-		// When a 32-bit ppc program is run under emulation on an Intel processor,
-		// we want any i386 dylibs (e.g. the emulator) to not load in the shared region
-		// because the shared region is being used by ppc dylibs
-		gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
-		return true;
-	}
-#endif
+	gLinkContext.progname				= (argv[0] != NULL) ? basename(argv[0]) : "";
+	gLinkContext.programVars.mh			= mainExecutableMH;
+	gLinkContext.programVars.NXArgcPtr	= &gLinkContext.argc;
+	gLinkContext.programVars.NXArgvPtr	= &gLinkContext.argv;
+	gLinkContext.programVars.environPtr	= &gLinkContext.envp;
+	gLinkContext.programVars.__prognamePtr=&gLinkContext.progname;
+	gLinkContext.mainExecutable			= NULL;
+	gLinkContext.imageSuffix			= NULL;
+	gLinkContext.prebindUsage			= ImageLoader::kUseAllPrebinding;
+	gLinkContext.sharedRegionMode		= ImageLoader::kUseSharedRegion;
+}
+
+
+#if __LP64__
+	#define LC_SEGMENT_COMMAND		LC_SEGMENT_64
+	#define macho_segment_command	segment_command_64
+	#define macho_section			section_64
+#else
+	#define LC_SEGMENT_COMMAND		LC_SEGMENT
+	#define macho_segment_command	segment_command
+	#define macho_section			section
+#endif
+
+
+//
+// Look for a special segment in the mach header. 
+// Its presences means that the binary wants to have DYLD ignore
+// DYLD_ environment variables.
+//
+static bool hasRestrictedSegment(const macho_header* mh)
+{
+	const uint32_t cmd_count = mh->ncmds;
+	const struct load_command* const cmds = (struct load_command*)(((char*)mh)+sizeof(macho_header));
+	const struct load_command* cmd = cmds;
+	for (uint32_t i = 0; i < cmd_count; ++i) {
+		switch (cmd->cmd) {
+			case LC_SEGMENT_COMMAND:
+			{
+				const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+				
+				//dyld::log("seg name: %s\n", seg->segname);
+				if (strcmp(seg->segname, "__RESTRICT") == 0) {
+					const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
+					const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
+					for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
+						if (strcmp(sect->sectname, "__restrict") == 0) 
+							return true;
+					}
+				}
+			}
+			break;
+		}
+		cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+	}
+		
 	return false;
 }
 
-void link(ImageLoader* image, ImageLoader::BindingLaziness bindness, ImageLoader::InitializerRunning runInitializers)
+#if SUPPORT_VERSIONED_PATHS
+//
+// Peeks at a dylib file and returns its current_version and install_name.
+// Returns false on error.
+//			
+static bool getDylibVersionAndInstallname(const char* dylibPath, uint32_t* version, char* installName)
+{
+	// open file (automagically closed when this function exits)
+	FileOpener file(dylibPath);
+	
+	if ( file.getFileDescriptor() == -1 ) 
+		return false;
+	
+	uint8_t firstPage[4096];
+	if ( pread(file.getFileDescriptor(), firstPage, 4096, 0) != 4096 )
+		return false;
+
+	// if fat wrapper, find usable sub-file
+	const fat_header* fileStartAsFat = (fat_header*)firstPage;
+	if ( fileStartAsFat->magic == OSSwapBigToHostInt32(FAT_MAGIC) ) {
+		uint64_t fileOffset;
+		uint64_t fileLength;
+		if ( fatFindBest(fileStartAsFat, &fileOffset, &fileLength) ) {
+			if ( pread(file.getFileDescriptor(), firstPage, 4096, fileOffset) != 4096 )
+				return false;
+		}
+		else {
+			return false;
+		}
+	}
+
+	// check mach-o header
+	const mach_header* mh = (mach_header*)firstPage;
+	if ( mh->magic != sMainExecutableMachHeader->magic ) 
+		return false;
+	if ( mh->cputype != sMainExecutableMachHeader->cputype )
+		return false;
+
+	// scan load commands for LC_ID_DYLIB
+	const uint32_t cmd_count = mh->ncmds;
+	const struct load_command* const cmds = (struct load_command*)(((char*)mh)+sizeof(macho_header));
+	const struct load_command* const cmdsReadEnd = (struct load_command*)(((char*)mh)+4096);
+	const struct load_command* cmd = cmds;
+	for (uint32_t i = 0; i < cmd_count; ++i) {
+		switch (cmd->cmd) {
+			case LC_ID_DYLIB:
+			{
+				const struct dylib_command* id = (struct dylib_command*)cmd;
+				*version = id->dylib.current_version;
+				if ( installName != NULL )
+					strlcpy(installName, (char *)id + id->dylib.name.offset, PATH_MAX);
+				return true;
+			}
+			break;
+		}
+		cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+		if ( cmd > cmdsReadEnd )
+			return false;
+	}
+	
+	return false;
+}
+#endif // SUPPORT_VERSIONED_PATHS
+						
+#if 0
+static void printAllImages()
+{
+	dyld::log("printAllImages()\n");
+	for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+		ImageLoader* image = *it;
+		dyld_image_states imageState = image->getState();
+		dyld::log("  state=%d, refcount=%d, name=%s\n", imageState, image->referenceCount(), image->getShortName());
+		image->printReferenceCounts();
+	}
+}
+#endif
+
+void link(ImageLoader* image, bool forceLazysBound, const ImageLoader::RPathChain& loaderRPaths)
 {
 	// add to list of known images.  This did not happen at creation time for bundles
-	if ( image->isBundle() )
+	if ( image->isBundle() && !image->isLinked() )
 		addImage(image);
 
 	// we detect root images as those not linked in yet 
 	if ( !image->isLinked() )
 		addRootImage(image);
 	
-	// notify ZeroLink of new image with concat of logical and physical name
-	if ( sBundleNotifier != NULL && image->isBundle() ) {
-		const int logicalLen = strlen(image->getLogicalPath());
-		char logAndPhys[strlen(image->getPath())+logicalLen+2];
-		strcpy(logAndPhys, image->getLogicalPath());
-		strcpy(&logAndPhys[logicalLen+1], image->getPath());
-		(*sBundleNotifier)(logAndPhys, image);
-	}
-
 	// process images
 	try {
-		image->link(gLinkContext, bindness, runInitializers, sAddImageCallbacks.size());
+		image->link(gLinkContext, forceLazysBound, false, loaderRPaths);
 	}
 	catch (const char* msg) {
-		sAllImagesMightContainUnlinkedImages = true;
-		throw msg;
-	}
-	
-#if OLD_GDB_DYLD_INTERFACE
-	// notify gdb that loaded libraries have changed
-	gdb_dyld_state_changed();
-#endif
-}
-
-
-//
-// _pthread_keys is partitioned in a lower part that dyld will use; libSystem
-// will use the upper part.  We set __pthread_tsd_first to 1 as the start of
-// the lower part.  Libc will take #1 and c++ exceptions will take #2.  There
-// is one free key=3 left.
-//
-extern "C" {
-	extern int __pthread_tsd_first;
-}
- 
+		garbageCollectImages();
+		throw;
+	}
+}
+
+
+void runInitializers(ImageLoader* image)
+{
+	// do bottom up initialization
+	ImageLoader::InitializerTimingList initializerTimes[sAllImages.size()];
+	initializerTimes[0].count = 0;
+	image->runInitializers(gLinkContext, initializerTimes[0]);
+}
+
+void garbageCollectImages()
+{
+	// keep scanning list of images until entire list is scanned with no unreferenced images
+	bool mightBeUnreferencedImages = true;
+	while ( mightBeUnreferencedImages ) {
+		mightBeUnreferencedImages = false;
+		for (std::vector<ImageLoader*>::iterator it=sAllImages.begin(); it != sAllImages.end(); it++) {
+			ImageLoader* image = *it;
+			if ( (image->referenceCount() == 0) && !image->neverUnload() && !image->isBeingRemoved() ) {
+				if ( image->isReferencedUpward() ) {
+					// temp hack for rdar://problem/10973109
+					// if an image is upwardly referenced, we really need to scan all images 
+					// to see if any are still using it.
+					continue;
+				}
+				try {
+					//dyld::log("garbageCollectImages: deleting %p %s\n", image, image->getPath());
+					image->setBeingRemoved();
+					removeImage(image);
+					ImageLoader::deleteImage(image);
+				}
+				catch (const char* msg) {
+					dyld::warn("problem deleting image: %s\n", msg);
+				}
+				mightBeUnreferencedImages = true;
+				break;
+			}
+		}
+	}
+	//printAllImages();
+}
+
+
+static void preflight_finally(ImageLoader* image)
+{
+	if ( image->isBundle() ) {
+		removeImageFromAllImages(image->machHeader());
+		ImageLoader::deleteImage(image);
+	}
+	sBundleBeingLoaded = NULL;
+	dyld::garbageCollectImages();
+}
+
+
+void preflight(ImageLoader* image, const ImageLoader::RPathChain& loaderRPaths)
+{
+	try {
+		if ( image->isBundle() ) 
+			sBundleBeingLoaded = image;	// hack
+		image->link(gLinkContext, false, true, loaderRPaths);
+	}
+	catch (const char* msg) {	
+		preflight_finally(image);
+		throw;
+	}
+	preflight_finally(image);
+}
+
+static void loadInsertedDylib(const char* path)
+{
+	ImageLoader* image = NULL;
+	try {
+		LoadContext context;
+		context.useSearchPaths		= false;
+		context.useFallbackPaths	= false;
+		context.useLdLibraryPath	= false;
+		context.implicitRPath		= false;
+		context.matchByInstallName	= false;
+		context.dontLoad			= false;
+		context.mustBeBundle		= false;
+		context.mustBeDylib			= true;
+		context.canBePIE			= false;
+		context.origin				= NULL;	// can't use @loader_path with DYLD_INSERT_LIBRARIES
+		context.rpath				= NULL;
+		image = load(path, context);
+		image->setNeverUnload();
+	}
+	catch (...) {
+		halt(dyld::mkstringf("could not load inserted library: %s\n", path));
+	}
+}
+
+static bool processRestricted(const macho_header* mainExecutableMH)
+{
+    // all processes with setuid or setgid bit set are restricted
+    if ( issetugid() ) {
+		sRestrictedReason = restrictedBySetGUid;
+		return true;
+	}
+		
+	const uid_t euid = geteuid();
+	if ( (euid != 0) && hasRestrictedSegment(mainExecutableMH) ) {
+		// existence of __RESTRICT/__restrict section make process restricted
+		sRestrictedReason = restrictedBySegment;
+		return true;
+	}
+	
+#if __MAC_OS_X_VERSION_MIN_REQUIRED    
+    // ask kernel if code signature of program makes it restricted
+    uint32_t flags;
+    if ( syscall(SYS_csops /* 169 */,
+                0 /* asking about myself */,
+                CS_OPS_STATUS,
+                &flags,
+                sizeof(flags)) != -1) {
+        if (flags & CS_RESTRICT) {
+			sRestrictedReason = restrictedByEntitlements;
+			return true;
+		}
+    }
+#endif
+    return false;
+}
+
+
+
+
+// <rdar://problem/10583252> Add dyld to uuidArray to enable symbolication of stackshots
+static void addDyldImageToUUIDList()
+{
+	const struct macho_header* mh = (macho_header*)&__dso_handle;
+	const uint32_t cmd_count = mh->ncmds;
+	const struct load_command* const cmds = (struct load_command*)((char*)mh + sizeof(macho_header));
+	const struct load_command* cmd = cmds;
+	for (uint32_t i = 0; i < cmd_count; ++i) {
+		switch (cmd->cmd) {
+			case LC_UUID: {
+				uuid_command* uc = (uuid_command*)cmd;
+				dyld_uuid_info info;
+				info.imageLoadAddress = (mach_header*)mh;
+				memcpy(info.imageUUID, uc->uuid, 16);
+				addNonSharedCacheImageUUID(info);
+				return;
+			}
+		}
+		cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+	}
+}
+
+
 
 //
 // Entry point for dyld.  The kernel loads dyld and jumps to __dyld_start which
@@ -1977,18 +3900,44 @@
 // Returns address of main() in target program which __dyld_start jumps to
 //
 uintptr_t
-_main(const struct mach_header* mainExecutableMH, int argc, const char* argv[], const char* envp[], const char* apple[])
+_main(const macho_header* mainExecutableMH, uintptr_t mainExecutableSlide, 
+		int argc, const char* argv[], const char* envp[], const char* apple[], 
+		uintptr_t* startGlue)
 {	
-	// set pthread keys to dyld range
-	__pthread_tsd_first = 1;
-	
-	bool isEmulated = checkEmulation();
+	uintptr_t result = 0;
+	CRSetCrashLogMessage("dyld: launch started");
+#ifdef ALTERNATIVE_LOGFILE
+	sLogfile = open(ALTERNATIVE_LOGFILE, O_WRONLY | O_CREAT | O_APPEND);
+	if ( sLogfile == -1 ) {
+		sLogfile = STDERR_FILENO;
+		dyld::log("error opening alternate log file %s, errno = %d\n", ALTERNATIVE_LOGFILE, errno);
+	}
+#endif
+
+#if LOG_BINDINGS
+	char bindingsLogPath[256];
+	
+	const char* shortProgName = "unknown";
+	if ( argc > 0 ) {
+		shortProgName = strrchr(argv[0], '/');
+		if ( shortProgName == NULL )
+			shortProgName = argv[0];
+		else 
+			++shortProgName;
+	}
+	mysprintf(bindingsLogPath, "/tmp/bindings/%d-%s", getpid(), shortProgName);
+	sBindingsLogfile = open(bindingsLogPath, O_WRONLY | O_CREAT, 0666);
+	if ( sBindingsLogfile == -1 ) {
+		::mkdir("/tmp/bindings", 0777);
+		sBindingsLogfile = open(bindingsLogPath, O_WRONLY | O_CREAT, 0666);
+	}
+	//dyld::log("open(%s) => %d, errno = %d\n", bindingsLogPath, sBindingsLogfile, errno);
+#endif	
+	setContext(mainExecutableMH, argc, argv, envp, apple);
+
 	// Pickup the pointer to the exec path.
 	sExecPath = apple[0];
-	if (isEmulated) {
-		// under Rosetta 
-		sExecPath = strdup(apple[0] + strlen(apple[0]) + 1);
-	}
+	bool ignoreEnvironmentVariables = false;
 	if ( sExecPath[0] != '/' ) {
 		// have relative path, use cwd to make absolute
 		char cwdbuff[MAXPATHLEN];
@@ -2001,84 +3950,127 @@
 			sExecPath = s;
 		}
 	}
-	uintptr_t result = 0;
 	sMainExecutableMachHeader = mainExecutableMH;
-	if ( issetugid() )
+    sProcessIsRestricted = processRestricted(mainExecutableMH);
+    if ( sProcessIsRestricted ) {
+#if SUPPORT_LC_DYLD_ENVIRONMENT
+		checkLoadCommandEnvironmentVariables();
+#if SUPPORT_VERSIONED_PATHS
+		checkVersionedPaths();
+#endif	
+#endif 	
 		pruneEnvironmentVariables(envp, &apple);
+		// set again because envp and apple may have changed or moved
+		setContext(mainExecutableMH, argc, argv, envp, apple);
+	}
 	else
-		checkEnvironmentVariables(envp, isEmulated);
+		checkEnvironmentVariables(envp, ignoreEnvironmentVariables);
 	if ( sEnv.DYLD_PRINT_OPTS ) 
 		printOptions(argv);
 	if ( sEnv.DYLD_PRINT_ENV ) 
 		printEnvironmentVariables(envp);
 	getHostInfo();
-	setContext(argc, argv, envp, apple);
-	ImageLoader::BindingLaziness bindness = sEnv.DYLD_BIND_AT_LAUNCH ? ImageLoader::kLazyAndNonLazy : ImageLoader::kNonLazyOnly;
-	
-	// load any inserted libraries before loading the main executable so that they are first in flat namespace
-	int insertLibrariesCount = 0;
-	if ( sEnv.DYLD_INSERT_LIBRARIES != NULL ) {
-		for (const char* const* lib = sEnv.DYLD_INSERT_LIBRARIES; *lib != NULL; ++lib) {
-			insertLibrariesCount++;
-		}
-	}
-	ImageLoader* insertedImages[insertLibrariesCount];
-	if ( insertLibrariesCount > 0 ) {
-		for (int i=0; i < insertLibrariesCount; ++i) {
-			try {
-				LoadContext context;
-				context.useSearchPaths		= false;
-				context.useLdLibraryPath	= false;
-				context.dontLoad			= false;
-				context.mustBeBundle		= false;
-				context.mustBeDylib			= true;
-				context.matchByInstallName	= false;
-				context.origin				= NULL;	// can't use @loader_path with DYLD_INSERT_LIBRARIES
-				context.rpath				= NULL;
-				insertedImages[i] = load(sEnv.DYLD_INSERT_LIBRARIES[i], context);
-			}
-			catch (...) {
-				char buf[strlen(sEnv.DYLD_INSERT_LIBRARIES[i])+50];
-				sprintf(buf, "could not load inserted library: %s\n", sEnv.DYLD_INSERT_LIBRARIES[i]);
-				insertedImages[i]  = NULL;
-				halt(buf);
-			}
-		}
-	}
-	
-	// load and link main executable
+	// install gdb notifier
+	stateToHandlers(dyld_image_state_dependents_mapped, sBatchHandlers)->push_back(notifyGDB);
+	stateToHandlers(dyld_image_state_mapped, sSingleHandlers)->push_back(updateAllImages);
+	// make initial allocations large enough that it is unlikely to need to be re-alloced
+	sAllImages.reserve(INITIAL_IMAGE_COUNT);
+	sImageRoots.reserve(16);
+	sAddImageCallbacks.reserve(4);
+	sRemoveImageCallbacks.reserve(4);
+	sImageFilesNeedingTermination.reserve(16);
+	sImageFilesNeedingDOFUnregistration.reserve(8);
+	
+#ifdef WAIT_FOR_SYSTEM_ORDER_HANDSHAKE
+	// <rdar://problem/6849505> Add gating mechanism to dyld support system order file generation process
+	WAIT_FOR_SYSTEM_ORDER_HANDSHAKE(dyld_all_image_infos.systemOrderFlag);
+#endif
+	
 	try {
-		sMainExecutable = instantiateFromLoadedImage(mainExecutableMH, sExecPath);
+		// add dyld itself to UUID list
+		addDyldImageToUUIDList();
+		CRSetCrashLogMessage("dyld: launch, loading dependent libraries");
+		// instantiate ImageLoader for main executable
+		sMainExecutable = instantiateFromLoadedImage(mainExecutableMH, mainExecutableSlide, sExecPath);
+		sMainExecutable->setNeverUnload();
 		gLinkContext.mainExecutable = sMainExecutable;
+		gLinkContext.processIsRestricted = sProcessIsRestricted;
+		// load shared cache
+		checkSharedRegionDisable();
+	#if DYLD_SHARED_CACHE_SUPPORT
+		if ( gLinkContext.sharedRegionMode != ImageLoader::kDontUseSharedRegion )
+			mapSharedCache();
+	#endif
+		// load any inserted libraries
+		if	( sEnv.DYLD_INSERT_LIBRARIES != NULL ) {
+			for (const char* const* lib = sEnv.DYLD_INSERT_LIBRARIES; *lib != NULL; ++lib) 
+				loadInsertedDylib(*lib);
+		}
+		// record count of inserted libraries so that a flat search will look at 
+		// inserted libraries, then main, then others.
+		sInsertedDylibCount = sAllImages.size()-1;
+
+		// link main executable
+		gLinkContext.linkingMainExecutable = true;
+		link(sMainExecutable, sEnv.DYLD_BIND_AT_LAUNCH, ImageLoader::RPathChain(NULL, NULL));
+		gLinkContext.linkingMainExecutable = false;
 		if ( sMainExecutable->forceFlat() ) {
 			gLinkContext.bindFlat = true;
 			gLinkContext.prebindUsage = ImageLoader::kUseNoPrebinding;
 		}
-		link(sMainExecutable, bindness, ImageLoader::kDontRunInitializers);
-		result = (uintptr_t)sMainExecutable->getMain();
+
+		// link any inserted libraries
+		// do this after linking main executable so that any dylibs pulled in by inserted 
+		// dylibs (e.g. libSystem) will not be in front of dylibs the program uses
+		if ( sInsertedDylibCount > 0 ) {
+			for(unsigned int i=0; i < sInsertedDylibCount; ++i) {
+				ImageLoader* image = sAllImages[i+1];
+				link(image, sEnv.DYLD_BIND_AT_LAUNCH, ImageLoader::RPathChain(NULL, NULL));
+				// only INSERTED libraries can interpose
+				image->registerInterposing();
+			}
+		}
+		
+		CRSetCrashLogMessage("dyld: launch, running initializers");
+	#if SUPPORT_OLD_CRT_INITIALIZATION
+		// Old way is to run initializers via a callback from crt1.o
+		if ( ! gRunInitializersOldWay ) 
+			initializeMainExecutable(); 
+	#else
+		// run all initializers
+		initializeMainExecutable(); 
+	#endif
+		// find entry point for main executable
+		result = (uintptr_t)sMainExecutable->getThreadPC();
+		if ( result != 0 ) {
+			// main executable uses LC_MAIN, needs to return to glue in libdyld.dylib
+			if ( (gLibSystemHelpers != NULL) && (gLibSystemHelpers->version >= 9) )
+				*startGlue = (uintptr_t)gLibSystemHelpers->startGlueToCallExit;
+			else
+				halt("libdyld.dylib support not present for LC_MAIN");
+		}
+		else {
+			// main executable uses LC_UNIXTHREAD, dyld needs to let "start" in program set up for main()
+			result = (uintptr_t)sMainExecutable->getMain();
+			*startGlue = NULL;
+		}
 	}
 	catch(const char* message) {
+		syncAllImages();
 		halt(message);
 	}
 	catch(...) {
-		fprintf(stderr, "dyld: launch failed\n");
-	}
-	
-	// Link in any inserted libraries.  
-	// Do this after link main executable so any extra libraries pulled in by inserted libraries are at end of flat namespace
-	if ( insertLibrariesCount > 0 ) {
-		for (int i=0; i < insertLibrariesCount; ++i) {
-			try {
-				if ( insertedImages[i] != NULL )
-					link(insertedImages[i], bindness, ImageLoader::kDontRunInitializers);
-			}
-			catch (const char* message) {
-				char buf[strlen(sEnv.DYLD_INSERT_LIBRARIES[i])+50+strlen(message)];
-				sprintf(buf, "could not link inserted library: %s\n%s\n", sEnv.DYLD_INSERT_LIBRARIES[i], message);
-				halt(buf);
-			}
-		}
-	}
+		dyld::log("dyld: launch failed\n");
+	}
+
+#ifdef ALTERNATIVE_LOGFILE
+	// only use alternate log during launch, otherwise file is open forever
+	if ( sLogfile != STDERR_FILENO ) {
+		close(sLogfile);
+		sLogfile = STDERR_FILENO;
+	}
+#endif
+	CRSetCrashLogMessage(NULL);
 	
 	return result;
 }