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src/ImageLoaderMachOCompressed.cpp dyld-132.13 dyld-210.2.3
--- dyld/dyld-132.13/src/ImageLoaderMachOCompressed.cpp
+++ dyld/dyld-210.2.3/src/ImageLoaderMachOCompressed.cpp
@@ -67,14 +67,13 @@
 
 		uint64_t slice = *p & 0x7f;
 
-		if (bit >= 64 || slice << bit >> bit != slice)
-			dyld::throwf("uleb128 too big");
+		if (bit > 63)
+			dyld::throwf("uleb128 too big for uint64, bit=%d, result=0x%0llX", bit, result);
 		else {
 			result |= (slice << bit);
 			bit += 7;
 		}
-	} 
-	while (*p++ & 0x80);
+	} while (*p++ & 0x80);
 	return result;
 }
 
@@ -88,7 +87,7 @@
 		if (p == end)
 			throw "malformed sleb128";
 		byte = *p++;
-		result |= ((byte & 0x7f) << bit);
+		result |= (((int64_t)(byte & 0x7f)) << bit);
 		bit += 7;
 	} while (byte & 0x80);
 	// sign extend negative numbers
@@ -108,11 +107,12 @@
 	image->setSlide(slide);
 
 	// for PIE record end of program, to know where to start loading dylibs
-	if ( (mh->flags & MH_PIE) && !context.noPIE )
+	if ( slide != 0 )
 		fgNextPIEDylibAddress = (uintptr_t)image->getEnd();
 	
 	image->setNeverUnload();
 	image->instantiateFinish(context);
+	image->setMapped(context);
 	
 	if ( context.verboseMapping ) {
 		dyld::log("dyld: Main executable mapped %s\n", path);
@@ -131,7 +131,8 @@
 // create image by mapping in a mach-o file
 ImageLoaderMachOCompressed* ImageLoaderMachOCompressed::instantiateFromFile(const char* path, int fd, const uint8_t* fileData, 
 															uint64_t offsetInFat, uint64_t lenInFat, const struct stat& info, 
-															unsigned int segCount, unsigned int libCount, const LinkContext& context)
+															unsigned int segCount, unsigned int libCount, 
+															const struct linkedit_data_command* codeSigCmd, const LinkContext& context)
 {
 	ImageLoaderMachOCompressed* image = ImageLoaderMachOCompressed::instantiateStart((macho_header*)fileData, path, segCount, libCount);
 
@@ -139,6 +140,12 @@
 		// record info about file  
 		image->setFileInfo(info.st_dev, info.st_ino, info.st_mtime);
 
+	#if CODESIGNING_SUPPORT
+		// if this image is code signed, let kernel validate signature before mapping any pages from image
+		if ( codeSigCmd != NULL )
+			image->loadCodeSignature(codeSigCmd, fd, offsetInFat);
+	#endif
+		
 		// mmap segments
 		image->mapSegments(fd, offsetInFat, lenInFat, info.st_size, context);
 
@@ -154,16 +161,20 @@
 		else if ( (installName != NULL) && (strcmp(path, "/usr/lib/libgcc_s.1.dylib") == 0) && (strcmp(installName, "/usr/lib/libSystem.B.dylib") == 0) )
 			image->setPathUnowned("/usr/lib/libSystem.B.dylib");
 #endif
-		else if ( path[0] != '/' ) {
+		else if ( (path[0] != '/') || (strstr(path, "../") != NULL) ) {
+			// rdar://problem/10733082 Fix up @rpath based paths during introspection
 			// rdar://problem/5135363 turn relative paths into absolute paths so gdb, Symbolication can later find them
 			char realPath[MAXPATHLEN];
-			if ( realpath(path, realPath) != NULL )
-				image->setPath(realPath);
+			if ( fcntl(fd, F_GETPATH, realPath) == 0 ) 
+				image->setPaths(path, realPath);
 			else
 				image->setPath(path);
 		}
 		else 
 			image->setPath(path);
+
+		// make sure path is stable before recording in dyld_all_image_infos
+		image->setMapped(context);
 
 		// pre-fetch content of __DATA and __LINKEDIT segment for faster launches
 		// don't do this on prebound images or if prefetching is disabled
@@ -183,8 +194,9 @@
 }
 
 // create image by using cached mach-o file
-ImageLoaderMachOCompressed* ImageLoaderMachOCompressed::instantiateFromCache(const macho_header* mh, const char* path, const struct stat& info,
-																unsigned int segCount, unsigned int libCount, const LinkContext& context)
+ImageLoaderMachOCompressed* ImageLoaderMachOCompressed::instantiateFromCache(const macho_header* mh, const char* path, long slide,
+																		const struct stat& info, unsigned int segCount,
+																		unsigned int libCount, const LinkContext& context)
 {
 	ImageLoaderMachOCompressed* image = ImageLoaderMachOCompressed::instantiateStart(mh, path, segCount, libCount);
 	try {
@@ -194,6 +206,7 @@
 		// remember this is from shared cache and cannot be unloaded
 		image->fInSharedCache = true;
 		image->setNeverUnload();
+		image->setSlide(slide);
 
 		// segments already mapped in cache
 		if ( context.verboseMapping ) {
@@ -204,6 +217,7 @@
 		}
 
 		image->instantiateFinish(context);
+		image->setMapped(context);
 	}
 	catch (...) {
 		// ImageLoader::setMapped() can throw an exception to block loading of image
@@ -236,6 +250,7 @@
 			image->setPath(moduleName);
 
 		image->instantiateFinish(context);
+		image->setMapped(context);
 	}
 	catch (...) {
 		// ImageLoader::setMapped() can throw an exception to block loading of image
@@ -281,9 +296,6 @@
 {
 	// now that segments are mapped in, get real fMachOData, fLinkEditBase, and fSlide
 	this->parseLoadCmds();
-		
-	// notify state change
-	this->setMapped(context);
 }
 
 uint32_t* ImageLoaderMachOCompressed::segmentCommandOffsets() const
@@ -295,8 +307,8 @@
 ImageLoader* ImageLoaderMachOCompressed::libImage(unsigned int libIndex) const
 {
 	const uintptr_t* images = ((uintptr_t*)(((uint8_t*)this) + sizeof(ImageLoaderMachOCompressed) + fSegmentsCount*sizeof(uint32_t)));
-	// mask off low bit
-	return (ImageLoader*)(images[libIndex] & (-2));
+	// mask off low bits
+	return (ImageLoader*)(images[libIndex] & (-4));
 }
 
 bool ImageLoaderMachOCompressed::libReExported(unsigned int libIndex) const
@@ -306,13 +318,22 @@
 	return ((images[libIndex] & 1) != 0);
 }	
 
-
-void ImageLoaderMachOCompressed::setLibImage(unsigned int libIndex, ImageLoader* image, bool reExported)
+bool ImageLoaderMachOCompressed::libIsUpward(unsigned int libIndex) const
+{
+	const uintptr_t* images = ((uintptr_t*)(((uint8_t*)this) + sizeof(ImageLoaderMachOCompressed) + fSegmentsCount*sizeof(uint32_t)));
+	// re-export flag is second bit
+	return ((images[libIndex] & 2) != 0);
+}	
+
+
+void ImageLoaderMachOCompressed::setLibImage(unsigned int libIndex, ImageLoader* image, bool reExported, bool upward)
 {
 	uintptr_t* images = ((uintptr_t*)(((uint8_t*)this) + sizeof(ImageLoaderMachOCompressed) + fSegmentsCount*sizeof(uint32_t)));
 	uintptr_t value = (uintptr_t)image;
 	if ( reExported ) 
 		value |= 1;
+	if ( upward ) 
+		value |= 2;
 	images[libIndex] = value;
 }
 
@@ -364,7 +385,7 @@
 		const char* adstr = "sequential";
 		if ( advise == MADV_FREE )
 			adstr = "free";
-		dyld::log("%18s %s 0x%0lX -> 0x%0lX\n", "__LINKEDIT", adstr, start, end-1);
+		dyld::log("%18s %s 0x%0lX -> 0x%0lX for %s\n", "__LINKEDIT", adstr, start, end-1, this->getPath());
 	}
 }
 
@@ -372,6 +393,9 @@
 
 void ImageLoaderMachOCompressed::rebaseAt(const LinkContext& context, uintptr_t addr, uintptr_t slide, uint8_t type)
 {
+	if ( context.verboseRebase ) {
+		dyld::log("dyld: rebase: %s:*0x%08lX += 0x%08lX\n", this->getShortName(), (uintptr_t)addr, slide);
+	}
 	//dyld::log("0x%08lX type=%d\n", addr, type);
 	uintptr_t* locationToFix = (uintptr_t*)addr;
 	switch (type) {
@@ -396,6 +420,7 @@
 
 void ImageLoaderMachOCompressed::rebase(const LinkContext& context)
 {
+	CRSetCrashLogMessage2(this->getPath());
 	const uintptr_t slide = this->fSlide;
 	const uint8_t* const start = fLinkEditBase + fDyldInfo->rebase_off;
 	const uint8_t* const end = &start[fDyldInfo->rebase_size];
@@ -481,70 +506,117 @@
 		free((void*)msg);
 		throw newMsg;
 	}
-}
-
-
+	CRSetCrashLogMessage2(NULL);
+}
+
+//
+// This function is the hotspot of symbol lookup.  It was pulled out of findExportedSymbol()
+// to enable it to be re-written in assembler if needed.
+//
+const uint8_t* ImageLoaderMachOCompressed::trieWalk(const uint8_t* start, const uint8_t* end, const char* s)
+{
+	const uint8_t* p = start;
+	while ( p != NULL ) {
+		uint32_t terminalSize = *p++;
+		if ( terminalSize > 127 ) {
+			// except for re-export-with-rename, all terminal sizes fit in one byte
+			--p;
+			terminalSize = read_uleb128(p, end);
+		}
+		if ( (*s == '\0') && (terminalSize != 0) ) {
+			//dyld::log("trieWalk(%p) returning %p\n", start, p);
+			return p;
+		}
+		const uint8_t* children = p + terminalSize;
+		//dyld::log("trieWalk(%p) sym=%s, terminalSize=%d, children=%p\n", start, s, terminalSize, children);
+		uint8_t childrenRemaining = *children++;
+		p = children;
+		uint32_t nodeOffset = 0;
+		for (; childrenRemaining > 0; --childrenRemaining) {
+			const char* ss = s;
+			//dyld::log("trieWalk(%p) child str=%s\n", start, (char*)p);
+			bool wrongEdge = false;
+			// scan whole edge to get to next edge
+			// if edge is longer than target symbol name, don't read past end of symbol name
+			char c = *p;
+			while ( c != '\0' ) {
+				if ( !wrongEdge ) {
+					if ( c != *ss )
+						wrongEdge = true;
+					++ss;
+				}
+				++p;
+				c = *p;
+			}
+			if ( wrongEdge ) {
+				// advance to next child
+				++p; // skip over zero terminator
+				// skip over uleb128 until last byte is found
+				while ( (*p & 0x80) != 0 )
+					++p;
+				++p; // skil over last byte of uleb128
+			}
+			else {
+ 				// the symbol so far matches this edge (child)
+				// so advance to the child's node
+				++p;
+				nodeOffset = read_uleb128(p, end);
+				s = ss;
+				//dyld::log("trieWalk() found matching edge advancing to node 0x%x\n", nodeOffset);
+				break;
+			}
+		}
+		if ( nodeOffset != 0 )
+			p = &start[nodeOffset];
+		else
+			p = NULL;
+	}
+	//dyld::log("trieWalk(%p) return NULL\n", start);
+	return NULL;
+}
 
 
 const ImageLoader::Symbol* ImageLoaderMachOCompressed::findExportedSymbol(const char* symbol, const ImageLoader** foundIn) const
 {
-	//dyld::log("findExportedSymbolCompressed(%s) in %s\n", symbol, this->getShortName());
+	//dyld::log("Compressed::findExportedSymbol(%s) in %s\n", symbol, this->getShortName());
 	if ( fDyldInfo->export_size == 0 )
 		return NULL;
+#if LOG_BINDINGS
+	dyld::logBindings("%s: %s\n", this->getShortName(), symbol);
+#endif
 	++ImageLoaderMachO::fgSymbolTrieSearchs;
 	const uint8_t* start = &fLinkEditBase[fDyldInfo->export_off];
 	const uint8_t* end = &start[fDyldInfo->export_size];
-	const uint8_t* p = start;
-	const char* s = symbol;
-	do {
-		const uint8_t terminalSize = *p++;
-		const uint8_t* children = p + terminalSize;
-		if ( (*s == '\0') && (terminalSize != 0) ) {
-			// found match, return pointer to terminal part of node
+	const uint8_t* foundNodeStart = this->trieWalk(start, end, symbol); 
+	if ( foundNodeStart != NULL ) {
+		const uint8_t* p = foundNodeStart;
+		const uint32_t flags = read_uleb128(p, end);
+		// found match, return pointer to terminal part of node
+		if ( flags & EXPORT_SYMBOL_FLAGS_REEXPORT ) {
+			// re-export from another dylib, lookup there
+			const uint32_t ordinal = read_uleb128(p, end);
+			const char* importedName = (char*)p;
+			if ( importedName[0] == '\0' )
+				importedName = symbol;
+			if ( (ordinal > 0) && (ordinal <= libraryCount()) ) {
+				const ImageLoader* reexportedFrom = libImage(ordinal-1);
+				//dyld::log("Compressed::findExportedSymbol(), %s -> %s/%s\n", symbol, reexportedFrom->getShortName(), importedName);
+				return reexportedFrom->findExportedSymbol(importedName, true, foundIn);
+			}
+			else {
+				//dyld::throwf("bad mach-o binary, library ordinal (%u) invalid (max %u) for re-exported symbol %s in %s",
+				//	ordinal, libraryCount(), symbol, this->getPath());
+			}
+		}
+		else {
 			//dyld::log("findExportedSymbol(%s) in %s found match, returning %p\n", symbol, this->getShortName(), p);
 			if ( foundIn != NULL )
 				*foundIn = (ImageLoader*)this;		
-			return (Symbol*)p;
-		}
-		const uint8_t childrenCount = *children++;
-		const uint8_t* e = children;
-		const uint8_t* newNode = NULL;
-		for (uint8_t i=0; i < childrenCount; ++i) {
-			const char* ss = s;
-			bool wrongEdge = false;
-			//dyld::log("findExportedSymbol() looking at edge %s for match to %s\n", e, s);
-			// scan whole edge to get to next edge
-			// if edge is longer than target symbol name, don't read past end of symbol name
-			while ( *e != '\0' ) {
-				if ( !wrongEdge ) {
-					if ( *e != *ss++ )
-						wrongEdge = true;
-				}
-				++e;
-			}
-			if ( wrongEdge ) {
-				// advance to next child
-				++e;
-				read_uleb128(e, end);
-			}
-			else {
-				// the symbol so far matches this edge (child)
-				// so advance to the child's node
-				++e;
-				uint32_t nodeOffset = read_uleb128(e, end);
-				newNode = &start[nodeOffset];
-				s = ss;
-				//dyld::log("findExportedSymbol() found matching edge advancing to node 0x%x\n", nodeOffset);
-				break;
-			}
-		}
-		if ( newNode != NULL )
-			p = newNode;
-		else {
-			//dyld::log("findExportedSymbol(%s) in %s failed\n", symbol, this->getShortName());
-			return NULL;
-		}
-	} while ( true );
+			// return pointer to terminal part of node
+			return (Symbol*)foundNodeStart;
+		}
+	}
+	return NULL;
 }
 
 
@@ -556,18 +628,46 @@
 }
 
 
-uintptr_t ImageLoaderMachOCompressed::exportedSymbolAddress(const Symbol* symbol) const
+uintptr_t ImageLoaderMachOCompressed::exportedSymbolAddress(const LinkContext& context, const Symbol* symbol, bool runResolver) const
 {
 	const uint8_t* exportNode = (uint8_t*)symbol;
 	const uint8_t* exportTrieStart = fLinkEditBase + fDyldInfo->export_off;
 	const uint8_t* exportTrieEnd = exportTrieStart + fDyldInfo->export_size;
 	if ( (exportNode < exportTrieStart) || (exportNode > exportTrieEnd) )
 		throw "symbol is not in trie";
+	//dyld::log("exportedSymbolAddress(): node=%p, nodeOffset=0x%04X in %s\n", symbol, (int)((uint8_t*)symbol - exportTrieStart), this->getShortName());
 	uint32_t flags = read_uleb128(exportNode, exportTrieEnd);
-	if ( (flags & EXPORT_SYMBOL_FLAGS_KIND_MASK) == EXPORT_SYMBOL_FLAGS_KIND_REGULAR )
+	if ( (flags & EXPORT_SYMBOL_FLAGS_KIND_MASK) == EXPORT_SYMBOL_FLAGS_KIND_REGULAR ) {
+		if ( runResolver && (flags & EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER) ) {
+			// this node has a stub and resolver, run the resolver to get target address
+			uintptr_t stub = read_uleb128(exportNode, exportTrieEnd) + (uintptr_t)fMachOData; // skip over stub
+			// <rdar://problem/10657737> interposing dylibs have the stub address as their replacee
+			for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
+				// replace all references to 'replacee' with 'replacement'
+				if ( stub == it->replacee ) {
+					if ( context.verboseInterposing ) {
+						dyld::log("dyld interposing: lazy replace 0x%lX with 0x%lX from %s\n", 
+								  it->replacee, it->replacement, this->getPath());
+					}
+					return it->replacement;
+				}
+			}
+			typedef uintptr_t (*ResolverProc)(void);
+			ResolverProc resolver = (ResolverProc)(read_uleb128(exportNode, exportTrieEnd) + (uintptr_t)fMachOData);
+			uintptr_t result = (*resolver)();
+			if ( context.verboseBind )
+				dyld::log("dyld: resolver at %p returned 0x%08lX\n", resolver, result);
+			return result;
+		}
 		return read_uleb128(exportNode, exportTrieEnd) + (uintptr_t)fMachOData;
+	}
+	else if ( (flags & EXPORT_SYMBOL_FLAGS_KIND_MASK) == EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL ) {
+		if ( flags & EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER )
+			dyld::throwf("unsupported exported symbol kind. flags=%d at node=%p", flags, symbol);
+		return read_uleb128(exportNode, exportTrieEnd) + (uintptr_t)fMachOData;
+	}
 	else
-		throw "unsupported exported symbol kind";
+		dyld::throwf("unsupported exported symbol kind. flags=%d at node=%p", flags, symbol);
 }
 
 bool ImageLoaderMachOCompressed::exportedSymbolIsWeakDefintion(const Symbol* symbol) const
@@ -614,36 +714,37 @@
 
 
 
-uintptr_t ImageLoaderMachOCompressed::resolveFlat(const LinkContext& context, const char* symbolName, bool weak_import, const ImageLoader** foundIn)
+uintptr_t ImageLoaderMachOCompressed::resolveFlat(const LinkContext& context, const char* symbolName, bool weak_import, 
+													bool runResolver, const ImageLoader** foundIn)
 {
 	const Symbol* sym;
 	if ( context.flatExportFinder(symbolName, &sym, foundIn) ) {
 		if ( (*foundIn != this) && !(*foundIn)->neverUnload() )
 				this->addDynamicReference(*foundIn);
-		return (*foundIn)->getExportedSymbolAddress(sym, context, this);
+		return (*foundIn)->getExportedSymbolAddress(sym, context, this, runResolver);
 	}
 	// if a bundle is loaded privately the above will not find its exports
 	if ( this->isBundle() && this->hasHiddenExports() ) {
 		// look in self for needed symbol
 		sym = this->ImageLoaderMachO::findExportedSymbol(symbolName, false, foundIn);
 		if ( sym != NULL )
-			return (*foundIn)->getExportedSymbolAddress(sym, context, this);
+			return (*foundIn)->getExportedSymbolAddress(sym, context, this, runResolver);
 	}
 	if ( weak_import ) {
 		// definition can't be found anywhere, ok because it is weak, just return 0
 		return 0;
 	}
-	throwSymbolNotFound(symbolName, this->getPath(), "flat namespace");
+	throwSymbolNotFound(context, symbolName, this->getPath(), "flat namespace");
 }
 
 
 uintptr_t ImageLoaderMachOCompressed::resolveTwolevel(const LinkContext& context, const ImageLoader* targetImage, bool weak_import, 
-												const char* symbolName, const ImageLoader** foundIn)
+												const char* symbolName, bool runResolver, const ImageLoader** foundIn)
 {
 	// two level lookup
 	const Symbol* sym = targetImage->findExportedSymbol(symbolName, true, foundIn);
 	if ( sym != NULL ) {
-		return (*foundIn)->getExportedSymbolAddress(sym, context, this);
+		return (*foundIn)->getExportedSymbolAddress(sym, context, this, runResolver);
 	}
 	
 	if ( weak_import ) {
@@ -652,13 +753,13 @@
 	}
 
 	// nowhere to be found
-	throwSymbolNotFound(symbolName, this->getPath(), targetImage->getPath());
+	throwSymbolNotFound(context, symbolName, this->getPath(), targetImage->getPath());
 }
 
 
 uintptr_t ImageLoaderMachOCompressed::resolve(const LinkContext& context, const char* symbolName, 
 													uint8_t symboFlags, int libraryOrdinal, const ImageLoader** targetImage,
-													LastLookup* last)
+													LastLookup* last, bool runResolver)
 {
 	*targetImage = NULL;
 	
@@ -675,7 +776,7 @@
 	bool weak_import = (symboFlags & BIND_SYMBOL_FLAGS_WEAK_IMPORT);
 	uintptr_t symbolAddress;
 	if ( context.bindFlat || (libraryOrdinal == BIND_SPECIAL_DYLIB_FLAT_LOOKUP) ) {
-		symbolAddress = this->resolveFlat(context, symbolName, weak_import, targetImage);
+		symbolAddress = this->resolveFlat(context, symbolName, weak_import, runResolver, targetImage);
 	}
 	else {
 		if ( libraryOrdinal == BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE ) {
@@ -706,7 +807,7 @@
 			}
 		}
 		else {
-			symbolAddress = resolveTwolevel(context, *targetImage, weak_import, symbolName, targetImage);
+			symbolAddress = resolveTwolevel(context, *targetImage, weak_import, symbolName, runResolver, targetImage);
 		}
 	}
 	
@@ -723,13 +824,14 @@
 }
 
 uintptr_t ImageLoaderMachOCompressed::bindAt(const LinkContext& context, uintptr_t addr, uint8_t type, const char* symbolName, 
-								uint8_t symboFlags, intptr_t addend, int libraryOrdinal, const char* msg, LastLookup* last)
+								uint8_t symboFlags, intptr_t addend, int libraryOrdinal, const char* msg, 
+								LastLookup* last, bool runResolver)
 {
 	const ImageLoader*	targetImage;
 	uintptr_t			symbolAddress;
 	
 	// resolve symbol
-	symbolAddress = this->resolve(context, symbolName, symboFlags, libraryOrdinal, &targetImage, last);
+	symbolAddress = this->resolve(context, symbolName, symboFlags, libraryOrdinal, &targetImage, last, runResolver);
 
 	// do actual update
 	return this->bindLocation(context, addr, symbolAddress, targetImage, type, symbolName, addend, msg);
@@ -746,28 +848,50 @@
 
 void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLazysBound)
 {
+	CRSetCrashLogMessage2(this->getPath());
+
 	// if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
 	// note: flat-namespace binaries need to have imports rebound (even if correctly prebound)
 	if ( this->usablePrebinding(context) ) {
 		// don't need to bind
 	}
 	else {
+	
+	#if TEXT_RELOC_SUPPORT
+		// if there are __TEXT fixups, temporarily make __TEXT writable
+		if ( fTextSegmentBinds ) 
+			this->makeTextSegmentWritable(context, true);
+	#endif
+	
 		// run through all binding opcodes
 		eachBind(context, &ImageLoaderMachOCompressed::bindAt);
 			
-		// if this image is in the shared cache, but depends on someting no longer in the shared cache,
+	#if TEXT_RELOC_SUPPORT
+		// if there were __TEXT fixups, restore write protection
+		if ( fTextSegmentBinds ) 
+			this->makeTextSegmentWritable(context, false);
+	#endif	
+	
+		// if this image is in the shared cache, but depends on something no longer in the shared cache,
 		// there is no way to reset the lazy pointers, so force bind them now
-		if ( forceLazysBound || fInSharedCache )
+		if ( forceLazysBound || fInSharedCache ) 
 			this->doBindJustLazies(context);
+            
+		// this image is in cache, but something below it is not.  If
+        // this image has lazy pointer to a resolver function, then
+        // the stub may have been altered to point to a shared lazy pointer.
+		if ( fInSharedCache ) 
+			this->updateOptimizedLazyPointers(context);
+	
+		// tell kernel we are done with chunks of LINKEDIT
+		if ( !context.preFetchDisabled ) 
+			this->markFreeLINKEDIT(context);
 	}
 	
 	// set up dyld entry points in image
 	// do last so flat main executables will have __dyld or __program_vars set up
 	this->setupLazyPointerHandler(context);
-	
-	// tell kernel we are done with chunks of LINKEDIT
-	if ( !context.preFetchDisabled ) 
-		this->markFreeLINKEDIT(context);
+	CRSetCrashLogMessage2(NULL);
 }
 
 
@@ -844,19 +968,19 @@
 				case BIND_OPCODE_DO_BIND:
 					if ( address >= segmentEndAddress ) 
 						throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last);
+					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
 					address += sizeof(intptr_t);
 					break;
 				case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
 					if ( address >= segmentEndAddress ) 
 						throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last);
+					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
 					address += read_uleb128(p, end) + sizeof(intptr_t);
 					break;
 				case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
 					if ( address >= segmentEndAddress ) 
 						throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last);
+					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
 					address += immediate*sizeof(intptr_t) + sizeof(intptr_t);
 					break;
 				case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
@@ -865,7 +989,7 @@
 					for (uint32_t i=0; i < count; ++i) {
 						if ( address >= segmentEndAddress ) 
 							throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-						(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last);
+						(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
 						address += skip + sizeof(intptr_t);
 					}
 					break;
@@ -946,7 +1070,7 @@
 				case BIND_OPCODE_DO_BIND:
 					if ( address >= segmentEndAddress ) 
 						throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "lazy forced", NULL);
+					(this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "lazy forced", NULL, true);
 					address += sizeof(intptr_t);
 					break;
 				case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
@@ -1039,12 +1163,25 @@
 }
 
 
-uintptr_t ImageLoaderMachOCompressed::doBindFastLazySymbol(uint32_t lazyBindingInfoOffset, const LinkContext& context)
-{
+uintptr_t ImageLoaderMachOCompressed::doBindFastLazySymbol(uint32_t lazyBindingInfoOffset, const LinkContext& context,
+															void (*lock)(), void (*unlock)())
+{
+	// <rdar://problem/8663923> race condition with flat-namespace lazy binding
+	if ( this->usesTwoLevelNameSpace() ) {
+		// two-level namespace lookup does not require lock because dependents can't be unloaded before this image
+	}
+	else {
+		// acquire dyld global lock
+		if ( lock != NULL )
+			lock();
+	}
+	
 	const uint8_t* const start = fLinkEditBase + fDyldInfo->lazy_bind_off;
 	const uint8_t* const end = &start[fDyldInfo->lazy_bind_size];
-	if ( lazyBindingInfoOffset > fDyldInfo->lazy_bind_size )
-		throw "fast lazy bind offset out of range";
+	if ( lazyBindingInfoOffset > fDyldInfo->lazy_bind_size ) {
+		dyld::throwf("fast lazy bind offset out of range (%u, max=%u) in image %s", 
+			lazyBindingInfoOffset, fDyldInfo->lazy_bind_size, this->getPath());
+	}
 
 	uint8_t type = BIND_TYPE_POINTER;
 	uintptr_t address = 0;
@@ -1094,7 +1231,9 @@
 				address = segActualLoadAddress(immediate) + read_uleb128(p, end);
 				break;
 			case BIND_OPCODE_DO_BIND:
-				result = this->bindAt(context, address, type, symbolName, 0, 0, libraryOrdinal, "lazy ", NULL);
+				
+			
+				result = this->bindAt(context, address, type, symbolName, 0, 0, libraryOrdinal, "lazy ", NULL, true);
 				break;
 			case BIND_OPCODE_SET_ADDEND_SLEB:
 			case BIND_OPCODE_ADD_ADDR_ULEB:
@@ -1105,6 +1244,12 @@
 				dyld::throwf("bad lazy bind opcode %d", *p);
 		}
 	}	
+	
+	if ( !this->usesTwoLevelNameSpace() ) {
+		// release dyld global lock
+		if ( unlock != NULL )
+			unlock();
+	}
 	return result;
 }
 
@@ -1290,6 +1435,35 @@
 		this->addDynamicReference(targetImage);
 }
 
+uintptr_t ImageLoaderMachOCompressed::interposeAt(const LinkContext& context, uintptr_t addr, uint8_t type, const char*, 
+												uint8_t, intptr_t, int, const char*, LastLookup*, bool runResolver)
+{
+	if ( type == BIND_TYPE_POINTER ) {
+		uintptr_t* fixupLocation = (uintptr_t*)addr;
+		uintptr_t value = *fixupLocation;
+		for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
+			// replace all references to 'replacee' with 'replacement'
+			if ( (value == it->replacee) && (this != it->replacementImage) ) {
+				if ( context.verboseInterposing ) {
+					dyld::log("dyld: interposing: at %p replace 0x%lX with 0x%lX in %s\n", 
+						fixupLocation, it->replacee, it->replacement, this->getPath());
+				}
+				*fixupLocation = it->replacement;
+			}
+		}
+	}
+	return 0;
+}
+
+void ImageLoaderMachOCompressed::doInterpose(const LinkContext& context)
+{
+	if ( context.verboseInterposing )
+		dyld::log("dyld: interposing %lu tuples onto image: %s\n", fgInterposingTuples.size(), this->getPath());
+
+	// update prebound symbols
+	eachBind(context, &ImageLoaderMachOCompressed::interposeAt);
+	eachLazyBind(context, &ImageLoaderMachOCompressed::interposeAt);
+}
 
 
 
@@ -1354,7 +1528,14 @@
 		}
 	}
 	if ( bestSymbol != NULL ) {
+#if __arm__
+		if (bestSymbol->n_desc & N_ARM_THUMB_DEF)
+			*closestAddr = (void*)((bestSymbol->n_value | 1) + fSlide);
+		else
+			*closestAddr = (void*)(bestSymbol->n_value + fSlide);
+#else
 		*closestAddr = (void*)(bestSymbol->n_value + fSlide);
+#endif
 		return &symbolTableStrings[bestSymbol->n_un.n_strx];
 	}
 	return NULL;
@@ -1368,3 +1549,96 @@
 }
 #endif
 
+
+#if __arm__ || __x86_64__
+void ImageLoaderMachOCompressed::updateAlternateLazyPointer(uint8_t* stub, void** originalLazyPointerAddr)
+{
+#if __arm__ 
+	uint32_t* instructions = (uint32_t*)stub;
+    // sanity check this is a stub we understand
+	if ( (instructions[0] != 0xe59fc004) || (instructions[1] != 0xe08fc00c) || (instructions[2] != 0xe59cf000) )
+		return;
+    
+	void** lazyPointerAddr = (void**)(instructions[3] + (stub + 12));
+#endif
+#if __x86_64__
+    // sanity check this is a stub we understand
+	if ( (stub[0] != 0xFF) || (stub[1] != 0x25) )
+		return;
+    int32_t ripOffset = *((int32_t*)(&stub[2]));
+	void** lazyPointerAddr = (void**)(ripOffset + stub + 6);
+#endif
+
+   // if stub does not use original lazy pointer (meaning it was optimized by update_dyld_shared_cache)
+    if ( lazyPointerAddr != originalLazyPointerAddr ) {
+        // copy newly re-bound lazy pointer value to shared lazy pointer
+        *lazyPointerAddr = *originalLazyPointerAddr;
+    }
+}
+#endif
+
+
+// <rdar://problem/8890875> overriding shared cache dylibs with resolvers fails
+void ImageLoaderMachOCompressed::updateOptimizedLazyPointers(const LinkContext& context)
+{
+#if __arm__ || __x86_64__
+	// find stubs and lazy pointer sections
+	const struct macho_section* stubsSection = NULL;
+	const struct macho_section* lazyPointerSection = NULL;
+	const dysymtab_command* dynSymbolTable = NULL;
+	const macho_header* mh = (macho_header*)fMachOData;
+	const uint32_t cmd_count = mh->ncmds;
+	const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
+	const struct load_command* cmd = cmds;
+	for (uint32_t i = 0; i < cmd_count; ++i) {
+		if (cmd->cmd == LC_SEGMENT_COMMAND) {
+			const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+			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) {
+				const uint8_t type = sect->flags & SECTION_TYPE;
+				if ( type == S_SYMBOL_STUBS ) 
+					stubsSection = sect;
+				else if ( type == S_LAZY_SYMBOL_POINTERS ) 
+					lazyPointerSection = sect;
+			}
+		}
+		else if ( cmd->cmd == LC_DYSYMTAB ) {
+			dynSymbolTable = (struct dysymtab_command*)cmd;
+		}
+		cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+	}
+	
+	// sanity check
+	if ( dynSymbolTable == NULL )
+		return;
+	if ( (stubsSection == NULL) || (lazyPointerSection == NULL) )
+		return;
+	const uint32_t stubsCount = stubsSection->size / stubsSection->reserved2;
+	const uint32_t lazyPointersCount = lazyPointerSection->size / sizeof(void*);
+	if ( stubsCount != lazyPointersCount )
+		return;
+	const uint32_t stubsIndirectTableOffset = stubsSection->reserved1;
+	const uint32_t lazyPointersIndirectTableOffset = lazyPointerSection->reserved1;
+	if ( (stubsIndirectTableOffset+stubsCount) > dynSymbolTable->nindirectsyms )
+		return;
+	if ( (lazyPointersIndirectTableOffset+lazyPointersCount) > dynSymbolTable->nindirectsyms )
+		return;
+	
+	// walk stubs and lazy pointers
+	const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[dynSymbolTable->indirectsymoff];
+	void** const lazyPointersStartAddr = (void**)(lazyPointerSection->addr + this->fSlide);
+	uint8_t* const stubsStartAddr = (uint8_t*)(stubsSection->addr + this->fSlide);
+	uint8_t* stub = stubsStartAddr;
+	void** lpa = lazyPointersStartAddr;
+	for(uint32_t i=0; i < stubsCount; ++i, stub += stubsSection->reserved2, ++lpa) {
+        // sanity check symbol index of stub and lazy pointer match
+		if ( indirectTable[stubsIndirectTableOffset+i] != indirectTable[lazyPointersIndirectTableOffset+i] ) 
+			continue;
+		this->updateAlternateLazyPointer(stub, lpa);
+	}
+	
+#endif
+}
+
+