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src/dyldAPIsInLibSystem.cpp dyld-551.4 dyld-852.2
--- dyld/dyld-551.4/src/dyldAPIsInLibSystem.cpp
+++ dyld/dyld-852.2/src/dyldAPIsInLibSystem.cpp
@@ -26,25 +26,38 @@
 #include <string.h>
 #include <malloc/malloc.h>
 #include <sys/mman.h>
-
+#include <execinfo.h>
+
+#include <TargetConditionals.h>
+#include <System/sys/csr.h>
 #include <crt_externs.h>
 #include <Availability.h>
+#if !TARGET_OS_DRIVERKIT
 #include <vproc_priv.h>
-
+#endif
 #include <dirent.h>
+#include <sys/types.h>
 #include <sys/stat.h>
-
-#include "mach-o/dyld_images.h"
-#include "mach-o/dyld.h"
-#include "mach-o/dyld_priv.h"
+#include <fcntl.h>
+#include <System/sys/codesign.h>
+#include <libc_private.h>
+
+#include <mach-o/dyld_images.h>
+#include <mach-o/dyld.h>
+#include <mach-o/dyld_priv.h>
+
+#include <ptrauth.h>
+
 #include "dyld_cache_format.h"
+#include "objc-shared-cache.h"
 
 #include "ImageLoader.h"
 #include "dyldLock.h"
-#include "start_glue.h"
-
-#include "../dyld3/APIs.h"
-#include "../dyld3/AllImages.h"
+
+#include "APIs.h"
+#include "AllImages.h"
+#include "StartGlue.h"
+#include "Tracing.h"
 
 
 // this was in dyld_priv.h but it is no longer exported
@@ -62,79 +75,77 @@
 //
 extern "C" int _dyld_func_lookup(const char* dyld_func_name, void **address);
 
-
-extern bool gUseDyld3;
-
-#ifndef LC_VERSION_MIN_MACOSX
-	#define LC_VERSION_MIN_MACOSX 0x24
-	struct version_min_command {
-		uint32_t	cmd;		/* LC_VERSION_MIN_MACOSX or
-					   LC_VERSION_MIN_IPHONEOS  */
-		uint32_t	cmdsize;	/* sizeof(struct min_version_command) */
-		uint32_t	version;	/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
-		uint32_t	sdk;		/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
-	};
+template<typename T>
+static void dyld_func_lookup_and_resign(const char *dyld_func_name, T *__ptrauth_dyld_function_ptr* address) {
+    void *funcAsVoidPtr;
+    int res = _dyld_func_lookup(dyld_func_name, &funcAsVoidPtr);
+    (void)res;
+
+    // If C function pointer discriminators are type-diverse this cast will be
+    // an authenticate and resign operation.
+    *address = reinterpret_cast<T *>(funcAsVoidPtr);
+}
+
+#if TARGET_OS_IOS && !TARGET_OS_SIMULATOR
+namespace dyld3 {
+    extern int compatFuncLookup(const char* name, void** address) __API_AVAILABLE(ios(13.0));
+}
+extern "C" void setLookupFunc(void*);
 #endif
 
-#ifndef LC_VERSION_MIN_IPHONEOS
-	#define LC_VERSION_MIN_IPHONEOS 0x25
-#endif
-
-#ifndef LC_VERSION_MIN_TVOS
-	#define LC_VERSION_MIN_TVOS 0x2F
-#endif
-
-#ifndef LC_VERSION_MIN_WATCHOS
-	#define LC_VERSION_MIN_WATCHOS 0x30
-#endif
-
-
-#ifndef LC_LOAD_UPWARD_DYLIB
-	#define	LC_LOAD_UPWARD_DYLIB (0x23|LC_REQ_DYLD)	/* load of dylib whose initializers run later */
-#endif
-
-#ifndef LC_BUILD_VERSION
-	#define LC_BUILD_VERSION 0x32 /* build for platform min OS version */
-
-	/*
-	 * The build_version_command contains the min OS version on which this 
-	 * binary was built to run for its platform.  The list of known platforms and
-	 * tool values following it.
-	 */
-	struct build_version_command {
-		uint32_t	cmd;		/* LC_BUILD_VERSION */
-		uint32_t	cmdsize;	/* sizeof(struct build_version_command) plus */
-								/* ntools * sizeof(struct build_tool_version) */
-		uint32_t	platform;	/* platform */
-		uint32_t	minos;		/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
-		uint32_t	sdk;		/* X.Y.Z is encoded in nibbles xxxx.yy.zz */
-		uint32_t	ntools;		/* number of tool entries following this */
-	};
-
-	struct build_tool_version {
-		uint32_t	tool;		/* enum for the tool */
-		uint32_t	version;	/* version number of the tool */
-	};
-
-	/* Known values for the platform field above. */
-	#define PLATFORM_MACOS		1
-	#define PLATFORM_IOS		2
-	#define PLATFORM_TVOS		3
-	#define PLATFORM_WATCHOS	4
-	#define PLATFORM_BRIDGEOS	5
-
-	/* Known values for the tool field above. */
-	#define TOOL_CLANG	1
-	#define TOOL_SWIFT	2
-	#define TOOL_LD		3
-#endif
+
+extern void* __ptrauth_dyld_address_auth gUseDyld3;
+
+
+// <rdar://problem/61161069> libdyld.dylib should use abort_with_payload() for asserts
+VIS_HIDDEN
+void abort_report_np(const char* format, ...)
+{
+    va_list list;
+    const char *str;
+    _SIMPLE_STRING s = _simple_salloc();
+    if ( s != NULL ) {
+        va_start(list, format);
+        _simple_vsprintf(s, format, list);
+        va_end(list);
+        str = _simple_string(s);
+    }
+    else {
+        // _simple_salloc failed, but at least format may have useful info by itself
+        str = format;
+    }
+    if ( gUseDyld3 ) {
+        dyld3::halt(str);
+    }
+    else {
+        typedef void (*funcType)(const char* msg) __attribute__((__noreturn__));
+        static funcType __ptrauth_dyld_function_ptr p = NULL;
+        dyld_func_lookup_and_resign("__dyld_halt", &p);
+        p(str);
+    }
+    // halt() doesn't return, so we can't call _simple_sfree
+}
+
+// libc uses assert()
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Winvalid-noreturn"
+VIS_HIDDEN
+void __assert_rtn(const char* func, const char* file, int line, const char* failedexpr)
+{
+    if (func == NULL) {
+        abort_report_np("Assertion failed: (%s), file %s, line %d.\n", failedexpr, file, line);
+    } else {
+        abort_report_np("Assertion failed: (%s), function %s, file %s, line %d.\n", failedexpr, func, file, line);
+    }
+}
+#pragma clang diagnostic pop
 
 
 // deprecated APIs are still availble on Mac OS X, but not on iPhone OS
-#if __IPHONE_OS_VERSION_MIN_REQUIRED	
+#if TARGET_OS_OSX
+	#define DEPRECATED_APIS_SUPPORTED 1
+#else
 	#define DEPRECATED_APIS_SUPPORTED 0
-#else
-	#define DEPRECATED_APIS_SUPPORTED 1
 #endif
 
 /*
@@ -203,10 +214,11 @@
  	typedef NSModule (*mcallback_t)(NSSymbol s, NSModule old, NSModule newhandler);
 	typedef void (*lcallback_t)(NSLinkEditErrors c, int errorNumber,
 								const char* fileName, const char* errorString);
-	static void (*p)(ucallback_t undefined, mcallback_t multiple, lcallback_t linkEdit) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_install_handlers", (void**)&p);
+	typedef void (*funcType)(ucallback_t undefined, mcallback_t multiple, lcallback_t linkEdit);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_install_handlers", &p);
 	mcallback_t m = handlers->multiple;
 	p(handlers->undefined, m, handlers->linkEdit);
 }
@@ -219,10 +231,11 @@
 		return dyld3::NSNameOfModule(module);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const char*  (*p)(NSModule module) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSNameOfModule", (void**)&p);
+    typedef const char* (*funcType)(NSModule module);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSNameOfModule", &p);
 	return(p(module));
 } 
 
@@ -234,10 +247,11 @@
 		return dyld3::NSLibraryNameForModule(module);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const char*  (*p)(NSModule module) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLibraryNameForModule", (void**)&p);
+    typedef const char*  (*funcType)(NSModule module);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLibraryNameForModule", &p);
 	return(p(module));
 }
 
@@ -249,10 +263,11 @@
 		return dyld3::NSIsSymbolNameDefined(symbolName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const char* symbolName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSIsSymbolNameDefined", (void**)&p);
+    typedef bool (*funcType)(const char* symbolName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSIsSymbolNameDefined", &p);
 	return(p(symbolName));
 }
 
@@ -265,11 +280,12 @@
 		return dyld3::NSIsSymbolNameDefinedWithHint(symbolName, libraryNameHint);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const char* symbolName,
-			  const char* libraryNameHint) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSIsSymbolNameDefinedWithHint", (void**)&p);
+    typedef bool (*funcType)(const char* symbolName,
+                             const char* libraryNameHint);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSIsSymbolNameDefinedWithHint", &p);
 	return(p(symbolName, libraryNameHint));
 }
 
@@ -282,11 +298,12 @@
 		return dyld3::NSIsSymbolNameDefinedInImage(image, symbolName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const struct mach_header *image,
-			  const char* symbolName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSIsSymbolNameDefinedInImage", (void**)&p);
+    typedef bool (*funcType)(const struct mach_header *image,
+                             const char* symbolName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSIsSymbolNameDefinedInImage", &p);
 	return(p(image, symbolName));
 }
 
@@ -298,10 +315,11 @@
 		return dyld3::NSLookupAndBindSymbol(symbolName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSSymbol (*p)(const char* symbolName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLookupAndBindSymbol", (void**)&p);
+    typedef NSSymbol (*funcType)(const char* symbolName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLookupAndBindSymbol", &p);
 	return(p(symbolName));
 }
 
@@ -314,11 +332,12 @@
 		return dyld3::NSLookupAndBindSymbolWithHint(symbolName, libraryNameHint);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSSymbol (*p)(const char* symbolName,
-			 const char* libraryNameHint) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLookupAndBindSymbolWithHint", (void**)&p);
+    typedef NSSymbol (*funcType)(const char* symbolName,
+                                 const char* libraryNameHint);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLookupAndBindSymbolWithHint", &p);
 	return(p(symbolName, libraryNameHint));
 }
 
@@ -331,10 +350,11 @@
 		return dyld3::NSLookupSymbolInModule(module, symbolName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSSymbol (*p)(NSModule module, const char* symbolName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLookupSymbolInModule", (void**)&p);
+    typedef NSSymbol (*funcType)(NSModule module, const char* symbolName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLookupSymbolInModule", &p);
 	return(p(module, symbolName));
 }
 
@@ -348,12 +368,13 @@
 		return dyld3::NSLookupSymbolInImage(image, symbolName, options);
 
  	DYLD_LOCK_THIS_BLOCK;
-    static NSSymbol (*p)(const struct mach_header *image,
-			 const char* symbolName,
-			 uint32_t options) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLookupSymbolInImage", (void**)&p);
+    typedef NSSymbol (*funcType)(const struct mach_header *image,
+                                 const char* symbolName,
+                                 uint32_t options);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLookupSymbolInImage", &p);
 	return(p(image, symbolName, options));
 }
 
@@ -365,10 +386,11 @@
 		return dyld3::NSNameOfSymbol(symbol);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static char * (*p)(NSSymbol symbol) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSNameOfSymbol",(void**)&p);
+    typedef char * (*funcType)(NSSymbol symbol);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSNameOfSymbol",&p);
 	return(p(symbol));
 }
 
@@ -380,10 +402,11 @@
 		return dyld3::NSAddressOfSymbol(symbol);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static void * (*p)(NSSymbol symbol) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSAddressOfSymbol", (void**)&p);
+    typedef void * (*funcType)(NSSymbol symbol);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSAddressOfSymbol", &p);
 	return(p(symbol));
 }
 
@@ -395,10 +418,11 @@
 		return dyld3::NSModuleForSymbol(symbol);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSModule (*p)(NSSymbol symbol) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSModuleForSymbol", (void**)&p);
+    typedef NSModule (*funcType)(NSSymbol symbol);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSModuleForSymbol", &p);
 	return(p(symbol));
 }
 
@@ -410,10 +434,11 @@
 		return dyld3::NSAddLibrary(pathName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const char* pathName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSAddLibrary", (void**)&p);
+    typedef bool (*funcType)(const char* pathName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSAddLibrary", &p);
 	return(p(pathName));
 }
 
@@ -425,10 +450,11 @@
 		return dyld3::NSAddLibrary(pathName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const char* pathName) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSAddLibraryWithSearching", (void**)&p);
+    typedef bool (*funcType)(const char* pathName);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSAddLibraryWithSearching", &p);
 	return(p(pathName));
 }
 
@@ -441,11 +467,12 @@
 		return dyld3::NSAddImage(image_name, options);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const struct mach_header * (*p)(const char* image_name,
-					   uint32_t options) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSAddImage", (void**)&p);
+    typedef const struct mach_header * (*funcType)(const char* image_name,
+                                                   uint32_t options);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSAddImage", &p);
 	return(p(image_name, options));
 }
 #endif // DEPRECATED_APIS_SUPPORTED
@@ -532,262 +559,84 @@
 	return (-1);
 }
 
-
-#define PACKED_VERSION(major, minor, tiny) ((((major) & 0xffff) << 16) | (((minor) & 0xff) << 8) | ((tiny) & 0xff))
-
-
-static bool getVersionLoadCommandInfo(const mach_header* mh, uint32_t* platform, uint32_t* minOS, uint32_t* sdk)
-{
-	const load_command* startCmds = NULL;
-	if ( mh->magic == MH_MAGIC_64 )
-		startCmds = (load_command*)((char *)mh + sizeof(mach_header_64));
-	else if ( mh->magic == MH_MAGIC )
-		startCmds = (load_command*)((char *)mh + sizeof(mach_header));
-	else
-		return false;  // not a mach-o file, or wrong endianness
-		
-	const load_command* const cmdsEnd = (load_command*)((char*)startCmds + mh->sizeofcmds);
-	const load_command* cmd = startCmds;
-	for(uint32_t i = 0; i < mh->ncmds; ++i) {
-	    const load_command* nextCmd = (load_command*)((char *)cmd + cmd->cmdsize);
-		if ( (cmd->cmdsize < 8) || (nextCmd > cmdsEnd) || (nextCmd < startCmds)) {
-			return 0;
-		}
-		const version_min_command* versCmd;
-		const build_version_command* buildVersCmd;
-		switch ( cmd->cmd ) {
-			case LC_VERSION_MIN_IPHONEOS:
-				versCmd = (version_min_command*)cmd;
-				*platform	= PLATFORM_IOS;
-				*minOS		= versCmd->version;
-				*sdk		= versCmd->sdk;
-				return true;
-			case LC_VERSION_MIN_MACOSX:
-				versCmd = (version_min_command*)cmd;
-				*platform	= PLATFORM_MACOS;
-				*minOS		= versCmd->version;
-				*sdk		= versCmd->sdk;
-				return true;
-			case LC_VERSION_MIN_TVOS:
-				versCmd = (version_min_command*)cmd;
-				*platform	= PLATFORM_TVOS;
-				*minOS		= versCmd->version;
-				*sdk		= versCmd->sdk;
-				return true;
-			case LC_VERSION_MIN_WATCHOS:
-				versCmd = (version_min_command*)cmd;
-				*platform	= PLATFORM_WATCHOS;
-				*minOS		= versCmd->version;
-				*sdk		= versCmd->sdk;
-				return true;
-			case LC_BUILD_VERSION:
-				buildVersCmd = (build_version_command*)cmd;
-				*platform	 = buildVersCmd->platform;
-				*minOS		 = buildVersCmd->minos;
-				*sdk		 = buildVersCmd->sdk;
-				return true;
-		}
-		cmd = nextCmd;
-	}
-	return false;
-}
-
-#if !__WATCH_OS_VERSION_MIN_REQUIRED && !__TV_OS_VERSION_MIN_REQUIRED
-static uint32_t deriveSDKVersFromDylibs(const mach_header* mh)
-{
-	const load_command* startCmds = NULL;
-	if ( mh->magic == MH_MAGIC_64 )
-		startCmds = (load_command*)((char *)mh + sizeof(mach_header_64));
-	else if ( mh->magic == MH_MAGIC )
-		startCmds = (load_command*)((char *)mh + sizeof(mach_header));
-	else
-		return 0;  // not a mach-o file, or wrong endianness
-		
-	const load_command* const cmdsEnd = (load_command*)((char*)startCmds + mh->sizeofcmds);
-	const dylib_command* dylibCmd;
-	const load_command* cmd = startCmds;
-	const char* dylibName;
-  #if __IPHONE_OS_VERSION_MIN_REQUIRED
-	uint32_t foundationVers = 0;
-  #else
-	uint32_t libSystemVers = 0;
-  #endif
-	for(uint32_t i = 0; i < mh->ncmds; ++i) {
-	    const load_command* nextCmd = (load_command*)((char *)cmd + cmd->cmdsize);
-		// <rdar://problem/14381579&16050962> sanity check size of command
-		if ( (cmd->cmdsize < 8) || (nextCmd > cmdsEnd) || (nextCmd < startCmds)) {
-			return 0;
-		}
-		switch ( cmd->cmd ) {
-			case LC_LOAD_DYLIB:
-			case LC_LOAD_WEAK_DYLIB:
-			case LC_LOAD_UPWARD_DYLIB:
-				dylibCmd = (dylib_command*)cmd;
-				// sanity check dylib command layout
-				if ( dylibCmd->dylib.name.offset > cmd->cmdsize )
-					return 0;
-				dylibName = (char*)dylibCmd + dylibCmd->dylib.name.offset;
-  #if __IPHONE_OS_VERSION_MIN_REQUIRED
-				if ( strcmp(dylibName, "/System/Library/Frameworks/Foundation.framework/Foundation") == 0 )
-					foundationVers = dylibCmd->dylib.current_version;
-  #else
-				if ( strcmp(dylibName, "/usr/lib/libSystem.B.dylib") == 0 )
-					libSystemVers = dylibCmd->dylib.current_version;
-  #endif
-				break;
-		}
-		cmd = nextCmd;
-	}
-
-	struct DylibToOSMapping {
-		uint32_t dylibVersion;
-		uint32_t osVersion;
-	};
-	
-  #if __IPHONE_OS_VERSION_MIN_REQUIRED
-	static const DylibToOSMapping foundationMapping[] = {
-		{ PACKED_VERSION(678,24,0), 0x00020000 },
-		{ PACKED_VERSION(678,26,0), 0x00020100 },
-		{ PACKED_VERSION(678,29,0), 0x00020200 },
-		{ PACKED_VERSION(678,47,0), 0x00030000 },
-		{ PACKED_VERSION(678,51,0), 0x00030100 },
-		{ PACKED_VERSION(678,60,0), 0x00030200 },
-		{ PACKED_VERSION(751,32,0), 0x00040000 },
-		{ PACKED_VERSION(751,37,0), 0x00040100 },
-		{ PACKED_VERSION(751,49,0), 0x00040200 },
-		{ PACKED_VERSION(751,58,0), 0x00040300 },
-		{ PACKED_VERSION(881,0,0),  0x00050000 },
-		{ PACKED_VERSION(890,1,0),  0x00050100 },
-		{ PACKED_VERSION(992,0,0),  0x00060000 },
-		{ PACKED_VERSION(993,0,0),  0x00060100 },
-		{ PACKED_VERSION(1038,14,0),0x00070000 },
-		{ PACKED_VERSION(0,0,0),    0x00070000 }
-		// We don't need to expand this table because all recent
-		// binaries have LC_VERSION_MIN_ load command.
-	};
-
-	if ( foundationVers != 0 ) {
-		uint32_t lastOsVersion = 0;
-		for (const DylibToOSMapping* p=foundationMapping; ; ++p) {
-			if ( p->dylibVersion == 0 )
-				return p->osVersion;
-			if ( foundationVers < p->dylibVersion )
-				return lastOsVersion;
-			lastOsVersion = p->osVersion;
-		}
-	}
-
-  #else
-	// Note: versions are for the GM release.  The last entry should
-	// always be zero.  At the start of the next major version,
-	// a new last entry needs to be added and the previous zero
-	// updated to the GM dylib version.
-	static const DylibToOSMapping libSystemMapping[] = {
-		{ PACKED_VERSION(88,1,3),   0x000A0400 },
-		{ PACKED_VERSION(111,0,0),  0x000A0500 },
-		{ PACKED_VERSION(123,0,0),  0x000A0600 },
-		{ PACKED_VERSION(159,0,0),  0x000A0700 },
-		{ PACKED_VERSION(169,3,0),  0x000A0800 },
-		{ PACKED_VERSION(1197,0,0), 0x000A0900 },
-		{ PACKED_VERSION(0,0,0),    0x000A0900 }
-		// We don't need to expand this table because all recent
-		// binaries have LC_VERSION_MIN_ load command.
-	};
-
-	if ( libSystemVers != 0 ) {
-		uint32_t lastOsVersion = 0;
-		for (const DylibToOSMapping* p=libSystemMapping; ; ++p) {
-			if ( p->dylibVersion == 0 )
-				return p->osVersion;
-			if ( libSystemVers < p->dylibVersion )
-				return lastOsVersion;
-			lastOsVersion = p->osVersion;
-		}
-	}
-  #endif
-  return 0;
+#if TARGET_OS_WATCH
+uint32_t dyld_get_program_sdk_watch_os_version()
+{
+    if (gUseDyld3)
+        return dyld3::dyld_get_program_sdk_watch_os_version();
+
+    __block uint32_t retval = 0;
+    __block bool versionFound = false;
+    dyld3::dyld_get_image_versions((mach_header*)_NSGetMachExecuteHeader(), ^(dyld_platform_t platform, uint32_t sdk_version, uint32_t min_version) {
+        if (versionFound) return;
+
+        if (dyld_get_base_platform(platform) == PLATFORM_WATCHOS) {
+            versionFound = true;
+            retval = sdk_version;
+        }
+    });
+
+    return retval;
+}
+
+uint32_t dyld_get_program_min_watch_os_version()
+{
+    if (gUseDyld3)
+        return dyld3::dyld_get_program_min_watch_os_version();
+
+    __block uint32_t retval = 0;
+    __block bool versionFound = false;
+    dyld3::dyld_get_image_versions((mach_header*)_NSGetMachExecuteHeader(), ^(dyld_platform_t platform, uint32_t sdk_version, uint32_t min_version) {
+        if (versionFound) return;
+
+        if (dyld_get_base_platform(platform) == PLATFORM_WATCHOS) {
+            versionFound = true;
+            retval = min_version;
+        }
+    });
+
+    return retval;
 }
 #endif
 
-
-#if __WATCH_OS_VERSION_MIN_REQUIRED
-static uint32_t watchVersToIOSVers(uint32_t vers)
-{
-	return vers + 0x00070000;
-}
-
-uint32_t dyld_get_program_sdk_watch_os_version()
-{
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_program_sdk_watch_os_version();
-
-	const mach_header* mh = (mach_header*)_NSGetMachExecuteHeader();
-	uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		if ( platform == PLATFORM_WATCHOS )
-				return sdk;
-	}
-	return 0;
-}
-
-uint32_t dyld_get_program_min_watch_os_version()
-{
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_program_min_watch_os_version();
-
-	const mach_header* mh = (mach_header*)_NSGetMachExecuteHeader();
-	uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		if ( platform == PLATFORM_WATCHOS )
-				return minOS;  // return raw minOS (not mapped to iOS version)
-	}
-	return 0;
-}
-
-#endif
-
-
-
 #if TARGET_OS_BRIDGE
-static uint32_t bridgeVersToIOSVers(uint32_t vers)
-{
-	return vers + 0x00090000;
-}
-
 uint32_t dyld_get_program_sdk_bridge_os_version()
 {
-	const mach_header* mh = (mach_header*)_NSGetMachExecuteHeader();
-	uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		if ( platform == PLATFORM_BRIDGEOS )
-				return sdk;
-	}
-	return 0;
+    if (gUseDyld3)
+        return dyld3::dyld_get_program_sdk_bridge_os_version();
+
+    __block uint32_t retval = 0;
+    __block bool versionFound = false;
+    dyld3::dyld_get_image_versions((mach_header*)_NSGetMachExecuteHeader(), ^(dyld_platform_t platform, uint32_t sdk_version, uint32_t min_version) {
+        if (versionFound) return;
+
+        if (dyld_get_base_platform(platform) == PLATFORM_BRIDGEOS) {
+            versionFound = true;
+            retval = sdk_version;
+        }
+    });
+
+    return retval;
 }
 
 uint32_t dyld_get_program_min_bridge_os_version()
 {
-	const mach_header* mh = (mach_header*)_NSGetMachExecuteHeader();
-	uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		if ( platform == PLATFORM_BRIDGEOS )
-				return minOS;  // return raw minOS (not mapped to iOS version)
-	}
-	return 0;
-}
-
+    if (gUseDyld3)
+        return dyld3::dyld_get_program_min_bridge_os_version();
+
+    __block uint32_t retval = 0;
+    __block bool versionFound = false;
+    dyld3::dyld_get_image_versions((mach_header*)_NSGetMachExecuteHeader(), ^(dyld_platform_t platform, uint32_t sdk_version, uint32_t min_version) {
+        if (versionFound) return;
+
+        if (dyld_get_base_platform(platform) == PLATFORM_BRIDGEOS) {
+            versionFound = true;
+            retval = min_version;
+        }
+    });
+
+    return retval;
+}
 #endif
 
 /*
@@ -801,112 +650,23 @@
  */
 uint32_t dyld_get_sdk_version(const mach_header* mh)
 {
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_sdk_version(mh);
-
-    uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		switch (platform) {
-#if TARGET_OS_BRIDGE
-			case PLATFORM_BRIDGEOS:
-				// new binary. sdk version looks like "2.0" but API wants "11.0"
-				return bridgeVersToIOSVers(sdk);
-			case PLATFORM_IOS:
-				// old binary. sdk matches API semantics so can return directly.
-				return sdk;
-#elif __WATCH_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_WATCHOS:
-				// new binary. sdk version looks like "2.0" but API wants "9.0"
-				return watchVersToIOSVers(sdk);
-			case PLATFORM_IOS:
-				// old binary. sdk matches API semantics so can return directly.
-				return sdk;
-#elif __TV_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_TVOS:
-			case PLATFORM_IOS:
-				return sdk;
-#elif __IPHONE_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_IOS:
-				if ( sdk != 0 )	// old binaries might not have SDK set
-					return sdk;
-				break;
-#else
-			case PLATFORM_MACOS:
-				if ( sdk != 0 )	// old binaries might not have SDK set
-					return sdk;
-				break;
-#endif
-		}
-	}
-
-#if __WATCH_OS_VERSION_MIN_REQUIRED || __TV_OS_VERSION_MIN_REQUIRED || TARGET_OS_BRIDGE
-	// All WatchOS and tv OS binaries should have version load command.
-	return 0;
-#else
-	// MacOSX and iOS have old binaries without version load commmand.
-	return deriveSDKVersFromDylibs(mh);
-#endif
+    return dyld3::dyld_get_sdk_version(mh);
 }
 
 uint32_t dyld_get_program_sdk_version()
 {
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_program_sdk_version();
-
-	return dyld_get_sdk_version((mach_header*)_NSGetMachExecuteHeader());
+    return dyld3::dyld_get_sdk_version((mach_header*)_NSGetMachExecuteHeader());
 }
 
 uint32_t dyld_get_min_os_version(const struct mach_header* mh)
 {
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_min_os_version(mh);
-
-	uint32_t platform;
-	uint32_t minOS;
-	uint32_t sdk;
-
-	if ( getVersionLoadCommandInfo(mh, &platform, &minOS, &sdk) ) {
-		switch (platform) {
-#if TARGET_OS_BRIDGE
-			case PLATFORM_BRIDGEOS:
-				// new binary. sdk version looks like "2.0" but API wants "11.0"
-				return bridgeVersToIOSVers(minOS);
-			case PLATFORM_IOS:
-				// old binary. sdk matches API semantics so can return directly.
-				return minOS;
-#elif __WATCH_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_WATCHOS:
-				// new binary. OS version looks like "2.0" but API wants "9.0"
-				return watchVersToIOSVers(minOS);
-			case PLATFORM_IOS:
-				// old binary. OS matches API semantics so can return directly.
-				return minOS;
-#elif __TV_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_TVOS:
-			case PLATFORM_IOS:
-				return minOS;
-#elif __IPHONE_OS_VERSION_MIN_REQUIRED
-			case PLATFORM_IOS:
-				return minOS;
-#else
-			case PLATFORM_MACOS:
-				return minOS;
-#endif
-		}
-	}
-	return 0;
+    return dyld3::dyld_get_min_os_version(mh);
 }
 
 
 uint32_t dyld_get_program_min_os_version()
 {
-	if ( gUseDyld3 )
-		return dyld3::dyld_get_program_min_os_version();
-
-	return dyld_get_min_os_version((mach_header*)_NSGetMachExecuteHeader());
+    return dyld3::dyld_get_min_os_version((mach_header*)_NSGetMachExecuteHeader());
 }
 
 
@@ -941,6 +701,44 @@
 	return false;
 }
 
+dyld_platform_t dyld_get_active_platform(void) {
+    if (gUseDyld3)
+        return dyld3::dyld_get_active_platform();
+
+    return (dyld_platform_t)_dyld_get_all_image_infos()->platform;
+}
+
+dyld_platform_t dyld_get_base_platform(dyld_platform_t platform) {
+    return dyld3::dyld_get_base_platform(platform);
+}
+
+bool dyld_is_simulator_platform(dyld_platform_t platform) {
+    return dyld3::dyld_is_simulator_platform(platform);
+}
+
+bool dyld_sdk_at_least(const struct mach_header* mh, dyld_build_version_t version) {
+    return dyld3::dyld_sdk_at_least(mh, version);
+}
+
+bool dyld_minos_at_least(const struct mach_header* mh, dyld_build_version_t version) {
+    return dyld3::dyld_minos_at_least(mh, version);
+}
+
+bool dyld_program_sdk_at_least(dyld_build_version_t version) {
+    return dyld3::dyld_program_sdk_at_least(version);
+}
+
+bool dyld_program_minos_at_least(dyld_build_version_t version) {
+    return dyld3::dyld_program_minos_at_least(version);
+}
+
+// Function that walks through the load commands and calls the internal block for every version found
+// Intended as a fallback for very complex (and rare) version checks, or for tools that need to
+// print our everything for diagnostic reasons
+void dyld_get_image_versions(const struct mach_header* mh, void (^callback)(dyld_platform_t platform, uint32_t sdk_version, uint32_t min_version)) {
+    dyld3::dyld_get_image_versions(mh, callback);
+}
+
 
 
 #if DEPRECATED_APIS_SUPPORTED
@@ -960,10 +758,11 @@
 		return dyld3::NSCreateObjectFileImageFromFile(pathName, objectFileImage);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSObjectFileImageReturnCode (*p)(const char*, NSObjectFileImage*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSCreateObjectFileImageFromFile", (void**)&p);
+    typedef NSObjectFileImageReturnCode (*funcType)(const char*, NSObjectFileImage*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSCreateObjectFileImageFromFile", &p);
 	return p(pathName, objectFileImage);
 }
 
@@ -981,14 +780,24 @@
 size_t size, 
 NSObjectFileImage *objectFileImage)
 {
+    // <rdar://problem/51812762> NSCreatObjectFileImageFromMemory fail opaquely if Hardened runtime is enabled
+    uint32_t flags;
+    if ( csops(0, CS_OPS_STATUS, &flags, sizeof(flags)) != -1 ) {
+        if ( (flags & (CS_ENFORCEMENT|CS_KILL)) == (CS_ENFORCEMENT|CS_KILL) ) {
+            //fprintf(stderr, "dyld: warning: NSCreatObjectFileImageFromMemory() cannot be used in harden process 0x%08X\n", flags);
+            return NSObjectFileImageAccess;
+        }
+    }
+
 	if ( gUseDyld3 )
 		return dyld3::NSCreateObjectFileImageFromMemory(address, size, objectFileImage);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSObjectFileImageReturnCode (*p)(const void*, size_t, NSObjectFileImage*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSCreateObjectFileImageFromMemory", (void**)&p);
+    typedef NSObjectFileImageReturnCode (*funcType)(const void*, size_t, NSObjectFileImage*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSCreateObjectFileImageFromMemory", &p);
 	return p(address, size, objectFileImage);
 }
 
@@ -1005,10 +814,10 @@
 NSObjectFileImage *objectFileImage)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static NSObjectFileImageReturnCode (*p)(const char*, NSObjectFileImage*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSCreateCoreFileImageFromFile", (void**)&p);
+    typedef NSObjectFileImageReturnCode (*funcType)(const char*, NSObjectFileImage*) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSCreateCoreFileImageFromFile", &p);
 	return p(pathName, objectFileImage);
 }
 #endif
@@ -1021,10 +830,11 @@
 		return dyld3::NSDestroyObjectFileImage(objectFileImage);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(NSObjectFileImage) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSDestroyObjectFileImage", (void**)&p);
+    typedef bool (*funcType)(NSObjectFileImage);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSDestroyObjectFileImage", &p);
 	return p(objectFileImage);
 }
 
@@ -1039,10 +849,11 @@
 		return dyld3::NSLinkModule(objectFileImage, moduleName, options);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static NSModule (*p)(NSObjectFileImage, const char*, unsigned long) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSLinkModule", (void**)&p);
+    typedef NSModule (*funcType)(NSObjectFileImage, const char*, unsigned long);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSLinkModule", &p);
 		
 	return p(objectFileImage, moduleName, options);
 }
@@ -1062,10 +873,11 @@
 		return dyld3::NSSymbolDefinitionCountInObjectFileImage(objectFileImage);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static uint32_t (*p)(NSObjectFileImage) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSSymbolDefinitionCountInObjectFileImage", (void**)&p);
+    typedef uint32_t (*funcType)(NSObjectFileImage);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSSymbolDefinitionCountInObjectFileImage", &p);
 		
 	return p(objectFileImage);
 }
@@ -1085,10 +897,11 @@
 		return dyld3::NSSymbolDefinitionNameInObjectFileImage(objectFileImage, ordinal);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const char*  (*p)(NSObjectFileImage, uint32_t) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSSymbolDefinitionNameInObjectFileImage", (void**)&p);
+    typedef const char*  (*funcType)(NSObjectFileImage, uint32_t);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSSymbolDefinitionNameInObjectFileImage", &p);
 		
 	return p(objectFileImage, ordinal);
 }
@@ -1105,10 +918,11 @@
 		return dyld3::NSSymbolReferenceCountInObjectFileImage(objectFileImage);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static uint32_t (*p)(NSObjectFileImage) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSSymbolReferenceCountInObjectFileImage", (void**)&p);
+    typedef uint32_t (*funcType)(NSObjectFileImage);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSSymbolReferenceCountInObjectFileImage", &p);
 		
 	return p(objectFileImage);
 }
@@ -1129,10 +943,11 @@
 		return dyld3::NSSymbolReferenceNameInObjectFileImage(objectFileImage, ordinal, tentative_definition);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const char*  (*p)(NSObjectFileImage, uint32_t, bool*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSSymbolReferenceNameInObjectFileImage", (void**)&p);
+    typedef const char*  (*funcType)(NSObjectFileImage, uint32_t, bool*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSSymbolReferenceNameInObjectFileImage", &p);
 		
 	return p(objectFileImage, ordinal, tentative_definition);
 }
@@ -1150,10 +965,11 @@
 		return dyld3::NSIsSymbolDefinedInObjectFileImage(objectFileImage, symbolName);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(NSObjectFileImage, const char*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSIsSymbolDefinedInObjectFileImage", (void**)&p);
+    typedef bool (*funcType)(NSObjectFileImage, const char*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSIsSymbolDefinedInObjectFileImage", &p);
 		
 	return p(objectFileImage, symbolName);
 }
@@ -1176,10 +992,11 @@
 		return dyld3::NSGetSectionDataInObjectFileImage(objectFileImage, segmentName, sectionName, size);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static void* (*p)(NSObjectFileImage, const char*, const char*, unsigned long*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_NSGetSectionDataInObjectFileImage", (void**)&p);
+    typedef void* (*funcType)(NSObjectFileImage, const char*, const char*, unsigned long*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_NSGetSectionDataInObjectFileImage", &p);
 		
 	return p(objectFileImage, segmentName, sectionName, size);
 }
@@ -1196,13 +1013,14 @@
 		return dyld3::NSLinkEditError(c, errorNumber, fileName, errorString);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(NSLinkEditErrors *c,
-		     int *errorNumber, 
-		     const char* *fileName,
-		     const char* *errorString) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_link_edit_error", (void**)&p);
+    typedef void (*funcType)(NSLinkEditErrors *c,
+                             int *errorNumber,
+                             const char* *fileName,
+                             const char* *errorString);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_link_edit_error", &p);
 	if(p != NULL)
 	    p(c, errorNumber, fileName, errorString);
 }
@@ -1216,10 +1034,11 @@
 		return dyld3::NSUnLinkModule(module, options);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(NSModule module, uint32_t options) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_unlink_module", (void**)&p);
+    typedef bool (*funcType)(NSModule module, uint32_t options);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_unlink_module", &p);
 
 	return p(module, options);
 }
@@ -1256,10 +1075,11 @@
 		return dyld3::_NSGetExecutablePath(buf, bufsize);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static int (*p)(char *buf, uint32_t *bufsize) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld__NSGetExecutablePath", (void**)&p);
+    typedef int (*funcType)(char *buf, uint32_t *bufsize);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld__NSGetExecutablePath", &p);
 	return(p(buf, bufsize));
 }
 
@@ -1270,11 +1090,15 @@
 void** address,
 NSModule* module)
 {
-	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(const char*, void** , NSModule*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_lookup_and_bind", (void**)&p);
+	if ( gUseDyld3 )
+		return dyld3::_dyld_lookup_and_bind(symbol_name, address, module);
+
+	DYLD_LOCK_THIS_BLOCK;
+    typedef void (*funcType)(const char*, void** , NSModule*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_lookup_and_bind", &p);
 	p(symbol_name, address, module);
 }
 
@@ -1286,10 +1110,11 @@
 NSModule* module)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(const char*, const char*, void**, NSModule*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_lookup_and_bind_with_hint", (void**)&p);
+    typedef void (*funcType)(const char*, const char*, void**, NSModule*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_lookup_and_bind_with_hint", &p);
 	p(symbol_name, library_name_hint, address, module);
 }
 
@@ -1301,10 +1126,10 @@
 NSModule* module)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(const char* , void**, NSModule*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_lookup_and_bind_objc", (void**)&p);
+    typedef void (*funcType)(const char* , void**, NSModule*) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_lookup_and_bind_objc", &p);
 	p(symbol_name, address, module);
 }
 #endif
@@ -1316,10 +1141,11 @@
 NSModule* module)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(const char*, void**, NSModule*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_lookup_and_bind_fully", (void**)&p);
+    typedef void (*funcType)(const char*, void**, NSModule*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_lookup_and_bind_fully", &p);
 	p(symbol_name, address, module);
 }
 
@@ -1328,10 +1154,11 @@
 const void* address)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const void*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_bind_fully_image_containing_address", (void**)&p);
+    typedef bool (*funcType)(const void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_bind_fully_image_containing_address", &p);
 	return p(address);
 }
 #endif // DEPRECATED_APIS_SUPPORTED
@@ -1351,12 +1178,15 @@
 		return dyld3::_dyld_register_func_for_add_image(func);
 
 	DYLD_LOCK_THIS_BLOCK;
-	typedef void (*callback_t)(const struct mach_header *mh, intptr_t vmaddr_slide);
-    static void (*p)(callback_t func) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_register_func_for_add_image", (void**)&p);
-	p(func);
+	// Func must be a "void *" because dyld itself calls it. DriverKit
+	// libdyld.dylib uses diversified C function pointers but its dyld (the
+	// plain OS one) doesn't, so it must be resigned with 0 discriminator.
+	typedef void (*funcType)(void *func);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_register_func_for_add_image", &p);
+	p(reinterpret_cast<void *>(func));
 }
 
 /*
@@ -1372,12 +1202,15 @@
 		return dyld3::_dyld_register_func_for_remove_image(func);
 
 	DYLD_LOCK_THIS_BLOCK;
-	typedef void (*callback_t)(const struct mach_header *mh, intptr_t vmaddr_slide);
-    static void (*p)(callback_t func) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_register_func_for_remove_image", (void**)&p);
-	p(func);
+	// Func must be a "void *" because dyld itself calls it. DriverKit
+	// libdyld.dylib uses diversified C function pointers but its dyld (the
+	// plain OS one) doesn't, so it must be resigned with 0 discriminator.
+	typedef void (*funcType)(void *func);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_register_func_for_remove_image", &p);
+	p(reinterpret_cast<void *>(func));
 }
 
 #if OBSOLETE_DYLD_API
@@ -1392,11 +1225,14 @@
 void (*func)(NSModule module))
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(void (*func)(NSModule module)) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_register_func_for_link_module", (void**)&p);
-	p(func);
+	// Func must be a "void *" because dyld itself calls it. DriverKit
+	// libdyld.dylib uses diversified C function pointers but its dyld (the
+	// plain OS one) doesn't, so it must be resigned with 0 discriminator.
+	static void (*funcType)(void *func) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_register_func_for_link_module", &p);
+	p(reinterpret_cast<void *>(func));
 }
 
 /*
@@ -1408,11 +1244,14 @@
 void (*func)(NSModule module))
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(void (*func)(NSModule module)) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_register_func_for_unlink_module", (void**)&p);
-	p(func);
+	// Func must be a "void *" because dyld itself calls it. DriverKit
+	// libdyld.dylib uses diversified C function pointers but its dyld (the
+	// plain OS one) doesn't, so it must be resigned with 0 discriminator.
+	static void (*funcType)(void *func) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_register_func_for_unlink_module", &p);
+	p(reinterpret_cast<void *>(func));
 }
 
 /*
@@ -1424,12 +1263,14 @@
 void (*func)(NSModule oldmodule, NSModule newmodule))
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(void (*func)(NSModule oldmodule,
-				  NSModule newmodule)) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_register_func_for_replace_module", (void**)&p);
-	p(func);
+	// Func must be a "void *" because dyld itself calls it. DriverKit
+	// libdyld.dylib uses diversified C function pointers but its dyld (the
+	// plain OS one) doesn't, so it must be resigned with 0 discriminator.
+    typedef void (*funcType)(void *func) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_register_func_for_replace_module", &p);
+	p(reinterpret_cast<void *>(func));
 }
 
 
@@ -1445,12 +1286,12 @@
 unsigned long *size)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(NSModule module,
-		     void **objc_module,
-		     unsigned long *size) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_objc_module_sect_for_module", (void**)&p);
+    typedef void (*funcType)(NSModule module,
+                             void **objc_module,
+                             unsigned long *size) = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_objc_module_sect_for_module", &p);
 	p(module, objc_module, size);
 }
 
@@ -1472,10 +1313,11 @@
 		return dyld3::_dyld_image_count();
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static uint32_t (*p)(void) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_image_count", (void**)&p);
+    typedef uint32_t (*funcType)(void);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_image_count", &p);
 	return(p());
 }
 
@@ -1486,10 +1328,11 @@
 		return dyld3::_dyld_get_image_header(image_index);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static struct mach_header * (*p)(uint32_t image_index) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_header", (void**)&p);
+    typedef struct mach_header * (*funcType)(uint32_t image_index);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_image_header", &p);
 	return(p(image_index));
 }
 
@@ -1500,10 +1343,11 @@
 		return dyld3::_dyld_get_image_vmaddr_slide(image_index);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static unsigned long (*p)(uint32_t image_index) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_vmaddr_slide", (void**)&p);
+    typedef unsigned long (*funcType)(uint32_t image_index);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_image_vmaddr_slide", &p);
 	return(p(image_index));
 }
 
@@ -1514,27 +1358,35 @@
 		return dyld3::_dyld_get_image_name(image_index);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static const char*  (*p)(uint32_t image_index) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_name", (void**)&p);
+    typedef const char*  (*funcType)(uint32_t image_index);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_image_name", &p);
 	return(p(image_index));
 }
 
 // SPI in Mac OS X 10.6
 intptr_t _dyld_get_image_slide(const struct mach_header* mh)
 {
-	if ( gUseDyld3 )
-		return dyld3::_dyld_get_image_slide(mh);
-
-	DYLD_NO_LOCK_THIS_BLOCK;
-    static intptr_t (*p)(const struct mach_header*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_slide", (void**)&p);
-	return(p(mh));
-}
-
+	// always use dyld3 version because it does better error handling
+	return dyld3::_dyld_get_image_slide(mh);
+}
+
+const struct mach_header *
+_dyld_get_prog_image_header()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_get_prog_image_header();
+
+    DYLD_LOCK_THIS_BLOCK;
+    typedef const struct mach_header * (*funcType)(void);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_get_prog_image_header", &p);
+    return p();
+}
 
 #if DEPRECATED_APIS_SUPPORTED
 bool
@@ -1544,10 +1396,11 @@
 		return dyld3::_dyld_image_containing_address(address);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const void*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_image_containing_address", (void**)&p);
+    typedef bool (*funcType)(const void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_image_containing_address", &p);
 	return(p(address));
 }
 
@@ -1559,41 +1412,43 @@
 		return dyld3::_dyld_get_image_header_containing_address(address);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static const struct mach_header * (*p)(const void*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_header_containing_address", (void**)&p);
+    typedef const struct mach_header * (*funcType)(const void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_image_header_containing_address", &p);
 	return p(address);
 }
 
 bool _dyld_launched_prebound(void)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(void) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_launched_prebound", (void**)&p);
+    typedef bool (*funcType)(void);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_launched_prebound", &p);
 	return(p());
 }
 
 bool _dyld_all_twolevel_modules_prebound(void)
 {
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(void) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_all_twolevel_modules_prebound", (void**)&p);
+    typedef bool (*funcType)(void);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_all_twolevel_modules_prebound", &p);
 	return(p());
 }
 #endif // DEPRECATED_APIS_SUPPORTED
 
 
-#include <dlfcn.h>
+#include <dlfcn_private.h>
 #include <stddef.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <mach-o/dyld.h>
-#include <servers/bootstrap.h>
 #include "dyldLibSystemInterface.h"
 
 
@@ -1648,16 +1503,29 @@
 	return (pthread_getspecific(dlerrorPerThreadKey) != NULL);
 }
 
+#if TARGET_OS_DRIVERKIT
+static bool isLaunchdOwned()
+{
+    return false;
+}
+#else
 // use non-lazy pointer to vproc_swap_integer so that lazy binding does not recurse
 typedef vproc_err_t (*vswapproc)(vproc_t vp, vproc_gsk_t key,int64_t *inval, int64_t *outval);
 static vswapproc swapProc = &vproc_swap_integer;
 
 static bool isLaunchdOwned()
 {
-	int64_t val = 0;
-	(*swapProc)(NULL, VPROC_GSK_IS_MANAGED, NULL, &val);
-	return ( val != 0 );
-}
+    static bool checked = false;
+    static bool result = false;
+    if ( !checked ) {
+        checked = true;
+	    int64_t val = 0;
+	    (*swapProc)(NULL, VPROC_GSK_IS_MANAGED, NULL, &val);
+	    result = ( val != 0 );
+    }
+    return result;
+}
+#endif
 
 static void shared_cache_missing()
 {
@@ -1669,39 +1537,78 @@
 	// leave until dyld's that might call this are rare
 }
 
+// FIXME: This is a mess. Why can't Driverkit have its own dyld?
+static int cxa_atexit_thunk(void (*func)(void *), void *arg, void *dso)
+{
+	// Func will have come from dyld and so be signed with 0 discriminator,
+	// resign it appropriately before passing to the real __cxa_atexit.
+	func = ptrauth_auth_and_resign(func, ptrauth_key_function_pointer, 0,
+	    ptrauth_key_function_pointer,
+	    ptrauth_function_pointer_type_discriminator(__typeof__(func)));
+	return __cxa_atexit(func, arg, dso);
+}
+
+template<typename FTy> static FTy *resign_for_dyld(FTy *func) {
+	return ptrauth_auth_and_resign(func, ptrauth_key_function_pointer,
+	    ptrauth_function_pointer_type_discriminator(__typeof__(func)),
+	    ptrauth_key_function_pointer, 0);
+}
+
 
 // the table passed to dyld containing thread helpers
-static dyld::LibSystemHelpers sHelpers = { 13, &dyldGlobalLockAcquire, &dyldGlobalLockRelease,
-									&getPerThreadBufferFor_dlerror, &malloc, &free, &__cxa_atexit,
-									&shared_cache_missing, &shared_cache_out_of_date,
-									NULL, NULL,
-									&pthread_key_create, &pthread_setspecific,
-									&malloc_size,
-									&pthread_getspecific,
-									&__cxa_finalize,
-									address_of_start,
-									&hasPerThreadBufferFor_dlerror,
-									&isLaunchdOwned,
-									&vm_allocate,
-									&mmap,
-									&__cxa_finalize_ranges
-									};
-
-
+static dyld::LibSystemHelpers sHelpers = { 13 };
+
+static const objc_opt::objc_opt_t* gObjCOpt = nullptr;
 //
 // during initialization of libSystem this routine will run
 // and call dyld, registering the helper functions.
 //
 extern "C" void tlv_initializer();
 void _dyld_initializer()
-{	
-   void (*p)(dyld::LibSystemHelpers*);
+{
+    sHelpers.acquireGlobalDyldLock = resign_for_dyld(&dyldGlobalLockAcquire);
+    sHelpers.releaseGlobalDyldLock = resign_for_dyld(&dyldGlobalLockRelease);
+    sHelpers.getThreadBufferFor_dlerror = resign_for_dyld(&getPerThreadBufferFor_dlerror);
+    sHelpers.malloc = resign_for_dyld(&malloc);
+    sHelpers.free = resign_for_dyld(&free);
+    sHelpers.cxa_atexit = resign_for_dyld(&cxa_atexit_thunk);
+    sHelpers.dyld_shared_cache_missing = resign_for_dyld(&shared_cache_missing);
+    sHelpers.dyld_shared_cache_out_of_date = resign_for_dyld(&shared_cache_out_of_date);
+    sHelpers.acquireDyldInitializerLock = NULL;
+    sHelpers.releaseDyldInitializerLock = NULL;
+    sHelpers.pthread_key_create = resign_for_dyld(&pthread_key_create);
+    sHelpers.pthread_setspecific = resign_for_dyld(&pthread_setspecific);
+    sHelpers.malloc_size = resign_for_dyld(&malloc_size);
+    sHelpers.pthread_getspecific = resign_for_dyld(&pthread_getspecific);
+    sHelpers.cxa_finalize = resign_for_dyld(&__cxa_finalize);
+    sHelpers.startGlueToCallExit = address_of_start;
+    sHelpers.hasPerThreadBufferFor_dlerror = resign_for_dyld(&hasPerThreadBufferFor_dlerror);
+    sHelpers.isLaunchdOwned = resign_for_dyld(&isLaunchdOwned);
+    sHelpers.vm_alloc = resign_for_dyld(&vm_allocate);
+    sHelpers.mmap = resign_for_dyld(&mmap);
+    sHelpers.cxa_finalize_ranges = resign_for_dyld(&__cxa_finalize_ranges);
+
+    typedef void (*funcType)(dyld::LibSystemHelpers*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    // Get the optimized objc pointer now that the cache is loaded
+    const dyld_all_image_infos* allInfo = _dyld_get_all_image_infos();
+    if ( allInfo != nullptr  ) {
+        const DyldSharedCache* cache = (const DyldSharedCache*)(allInfo->sharedCacheBaseAddress);
+        if ( cache != nullptr )
+            gObjCOpt = cache->objcOpt();
+    }
 
 	if ( gUseDyld3 ) {
 		dyld3::gAllImages.applyInitialImages();
+#if TARGET_OS_IOS && !TARGET_OS_SIMULATOR
+        // For binaries built before 13.0, set the lookup function if they need it
+        if (dyld_get_program_sdk_version() < DYLD_PACKED_VERSION(13,0,0))
+            setLookupFunc((void*)&dyld3::compatFuncLookup);
+#endif
 	}
 	else {
-		_dyld_func_lookup("__dyld_register_thread_helpers", (void**)&p);
+		dyld_func_lookup_and_resign("__dyld_register_thread_helpers", &p);
 		if(p != NULL)
 			p(&sHelpers);
 	}
@@ -1709,103 +1616,172 @@
 	tlv_initializer();
 }
 
-
+int dladdr(const void* addr, Dl_info* info)
+{
+    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_DLADDR, (uint64_t)addr, 0, 0);
+    int result = 0;
+    if ( gUseDyld3 ) {
+        result = dyld3::dladdr(addr, info);
+    } else {
+        DYLD_LOCK_THIS_BLOCK;
+        typedef int (*funcType)(const void* , Dl_info*);
+        static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+        if(p == NULL)
+            dyld_func_lookup_and_resign("__dyld_dladdr", &p);
+        result = p(addr, info);
+    }
+    timer.setData4(result);
+    timer.setData5(info != NULL ? info->dli_fbase : 0);
+    timer.setData6(info != NULL ? info->dli_saddr : 0);
+    return result;
+}
+
+#if !TARGET_OS_DRIVERKIT
 char* dlerror()
 {
 	if ( gUseDyld3 )
 		return dyld3::dlerror();
 
 	DYLD_LOCK_THIS_BLOCK;
-    static char* (*p)() = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dlerror", (void**)&p);
+    typedef char* (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_dlerror", &p);
 	return(p());
 }
 
-int dladdr(const void* addr, Dl_info* info)
-{
-	if ( gUseDyld3 )
-		return dyld3::dladdr(addr, info);
-
-	DYLD_LOCK_THIS_BLOCK;
-    static int (*p)(const void* , Dl_info*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dladdr", (void**)&p);
-	return(p(addr, info));
-}
-
 int dlclose(void* handle)
 {
-	if ( gUseDyld3 )
+    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_DLCLOSE, (uint64_t)handle, 0, 0);
+    int result = 0;
+    if ( gUseDyld3 ) {
+        timer.setData4(result);
 		return dyld3::dlclose(handle);
-
-	DYLD_LOCK_THIS_BLOCK;
-    static int (*p)(void* handle) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dlclose", (void**)&p);
-	return(p(handle));
+    }
+
+	DYLD_LOCK_THIS_BLOCK;
+    typedef int (*funcType)(void* handle);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_dlclose", &p);
+    result = p(handle);
+    timer.setData4(result);
+	return result;
+}
+
+static void* dlopen_internal(const char* path, int mode, void* callerAddress)
+{
+    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_DLOPEN, path, mode, 0);
+    void* result = nullptr;
+    if ( gUseDyld3 ) {
+        result = dyld3::dlopen_internal(path, mode, callerAddress);
+        timer.setData4(result);
+        return result;
+    }
+
+    // dlopen is special. locking is done inside dyld to allow initializer to run without lock
+    DYLD_NO_LOCK_THIS_BLOCK;
+
+    typedef void* (*funcType)(const char* path, int, void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_dlopen_internal", &p);
+    result = p(path, mode, callerAddress);
+    // use asm block to prevent tail call optimization
+    // this is needed because dlopen uses __builtin_return_address() and depends on this glue being in the frame chain
+    // <rdar://problem/5313172 dlopen() looks too far up stack, can cause crash>
+    __asm__ volatile("");
+    timer.setData4(result);
+
+	return result;
 }
 
 void* dlopen(const char* path, int mode)
-{	
-	if ( gUseDyld3 )
-		return dyld3::dlopen(path, mode);
-
-	// dlopen is special. locking is done inside dyld to allow initializer to run without lock
+{
+    void* result = dlopen_internal(path, mode, __builtin_return_address(0));
+    if ( result )
+        return result;
+
+
+    return nullptr;
+}
+
+void* dlopen_from(const char* path, int mode, void* addressInCaller)
+{
+#if __has_feature(ptrauth_calls)
+    addressInCaller = __builtin_ptrauth_strip(addressInCaller, ptrauth_key_asia);
+#endif
+    return dlopen_internal(path, mode, addressInCaller);
+}
+
+#if !__i386__
+void* dlopen_audited(const char* path, int mode)
+{
+	return dlopen(path, mode);
+}
+#endif // !__i386__
+
+bool dlopen_preflight(const char* path)
+{
+    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_DLOPEN_PREFLIGHT, path, 0, 0);
+    bool result = false;
+
+    if ( gUseDyld3 ) {
+        result = dyld3::dlopen_preflight_internal(path);
+        timer.setData4(result);
+        return result;
+    }
+
+    DYLD_LOCK_THIS_BLOCK;
+    typedef bool (*funcType)(const char* path, void* callerAddress);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_dlopen_preflight_internal", &p);
+    result = p(path, __builtin_return_address(0));
+    timer.setData4(result);
+    return result;
+}
+
+void* dlsym(void* handle, const char* symbol)
+{
+    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_DLSYM, handle, symbol, 0);
+    void* result = nullptr;
+
+    if ( gUseDyld3 ) {
+        result = dyld3::dlsym_internal(handle, symbol, __builtin_return_address(0));
+        timer.setData4(result);
+        return result;
+    }
+
+    DYLD_LOCK_THIS_BLOCK;
+    typedef void* (*funcType)(void* handle, const char* symbol, void *callerAddress);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_dlsym_internal", &p);
+    result = p(handle, symbol, __builtin_return_address(0));
+    timer.setData4(result);
+    return result;
+}
+#endif // !TARGET_OS_DRIVERKIT
+
+
+const struct dyld_all_image_infos* _dyld_get_all_image_infos()
+{
+	if ( gUseDyld3 )
+		return dyld3::_dyld_get_all_image_infos();
+
 	DYLD_NO_LOCK_THIS_BLOCK;
-	
-    static void* (*p)(const char* path, int) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dlopen", (void**)&p);
-	void* result = p(path, mode);
-	// use asm block to prevent tail call optimization
-	// this is needed because dlopen uses __builtin_return_address() and depends on this glue being in the frame chain
-	// <rdar://problem/5313172 dlopen() looks too far up stack, can cause crash>
-	__asm__ volatile(""); 
-	
-	return result;
-}
-
-bool dlopen_preflight(const char* path)
-{
-	if ( gUseDyld3 )
-		return dyld3::dlopen_preflight(path);
-
-	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(const char* path) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dlopen_preflight", (void**)&p);
-	return(p(path));
-}
-
-void* dlsym(void* handle, const char* symbol)
-{
-	if ( gUseDyld3 )
-		return dyld3::dlsym(handle, symbol);
-
-	DYLD_LOCK_THIS_BLOCK;
-    static void* (*p)(void* handle, const char* symbol) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_dlsym", (void**)&p);
-	return(p(handle, symbol));
-}
-
-const struct dyld_all_image_infos* _dyld_get_all_image_infos()
-{
-	if ( gUseDyld3 )
-		return dyld3::_dyld_get_all_image_infos();
-
-	DYLD_NO_LOCK_THIS_BLOCK;
-    static struct dyld_all_image_infos* (*p)() = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_all_image_infos", (void**)&p);
+    typedef struct dyld_all_image_infos* (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_all_image_infos", &p);
 	return p();
 }
 
@@ -1816,10 +1792,11 @@
 		return dyld3::_dyld_find_unwind_sections(addr, info);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static void* (*p)(void*, dyld_unwind_sections*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_find_unwind_sections", (void**)&p);
+    typedef void* (*funcType)(void*, dyld_unwind_sections*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_find_unwind_sections", &p);
 	return p(addr, info);
 }
 #endif
@@ -1830,10 +1807,11 @@
 void* _dyld_fast_stub_entry(void* loadercache, long lazyinfo)
 {
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static void* (*p)(void*, long) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_fast_stub_entry", (void**)&p);
+    typedef void* (*funcType)(void*, long);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_fast_stub_entry", &p);
 	return p(loadercache, lazyinfo);
 }
 #endif
@@ -1845,10 +1823,11 @@
 		return dyld3::dyld_image_path_containing_address(addr);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static const char* (*p)(const void*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_image_path_containing_address", (void**)&p);
+    typedef const char* (*funcType)(const void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_image_path_containing_address", &p);
 	return p(addr);
 }
 
@@ -1858,10 +1837,11 @@
 		return dyld3::dyld_image_header_containing_address(addr);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static const mach_header* (*p)(const void*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_image_header_containing_address", (void**)&p);
+    typedef const mach_header* (*funcType)(const void*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_image_header_containing_address", &p);
 	return p(addr);
 }
 
@@ -1872,10 +1852,11 @@
 		return dyld3::dyld_shared_cache_some_image_overridden();
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static bool (*p)() = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_shared_cache_some_image_overridden", (void**)&p);
+    typedef bool (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_shared_cache_some_image_overridden", &p);
 	return p();
 }
 
@@ -1885,10 +1866,11 @@
 		return dyld3::_dyld_get_shared_cache_uuid(uuid);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static bool (*p)(uuid_t) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_shared_cache_uuid", (void**)&p);
+    typedef bool (*funcType)(uuid_t);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_shared_cache_uuid", &p);
 	return p(uuid);
 }
 
@@ -1898,13 +1880,114 @@
 		return dyld3::_dyld_get_shared_cache_range(length);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static const void* (*p)(size_t*) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_get_shared_cache_range", (void**)&p);
+    typedef const void* (*funcType)(size_t*);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_get_shared_cache_range", &p);
 	return p(length);
 }
 
+bool _dyld_shared_cache_optimized()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_shared_cache_optimized();
+
+    const dyld_all_image_infos* allInfo = _dyld_get_all_image_infos();
+    if ( allInfo != nullptr  ) {
+        const dyld_cache_header* cacheHeader = (dyld_cache_header*)(allInfo->sharedCacheBaseAddress);
+        if ( cacheHeader != nullptr )
+            return (cacheHeader->cacheType == kDyldSharedCacheTypeProduction);
+    }
+    return false;
+}
+
+bool _dyld_shared_cache_is_locally_built()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_shared_cache_is_locally_built();
+
+    const dyld_all_image_infos* allInfo = _dyld_get_all_image_infos();
+    if ( allInfo != nullptr  ) {
+        const dyld_cache_header* cacheHeader = (dyld_cache_header*)(allInfo->sharedCacheBaseAddress);
+        if ( cacheHeader != nullptr )
+            return (cacheHeader->locallyBuiltCache == 1);
+    }
+    return false;
+}
+
+const char* _dyld_shared_cache_real_path(const char* path)
+{
+    const dyld_all_image_infos* allInfo = _dyld_get_all_image_infos();
+    if ( allInfo != nullptr  ) {
+        const DyldSharedCache* cache = (const DyldSharedCache*)(allInfo->sharedCacheBaseAddress);
+        if ( cache != nullptr )
+            return cache->getCanonicalPath(path);
+    }
+    return nullptr;
+}
+
+bool _dyld_shared_cache_contains_path(const char* path)
+{
+    return _dyld_shared_cache_real_path(path) != nullptr;
+}
+
+
+uint32_t _dyld_launch_mode()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_launch_mode();
+
+    // in dyld2 mode all flag bits are zero
+    return 0;
+}
+
+void _dyld_images_for_addresses(unsigned count, const void* addresses[], struct dyld_image_uuid_offset infos[])
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_images_for_addresses(count, addresses, infos);
+
+    DYLD_NO_LOCK_THIS_BLOCK;
+    typedef const void (*funcType)(unsigned, const void*[], struct dyld_image_uuid_offset[]);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_images_for_addresses", &p);
+    return p(count, addresses, infos);
+}
+
+void _dyld_register_for_image_loads(void (*func)(const mach_header* mh, const char* path, bool unloadable))
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_register_for_image_loads(func);
+
+    DYLD_NO_LOCK_THIS_BLOCK;
+    typedef const void (*funcType)(void (*)(const mach_header* mh, const char* path, bool unloadable));
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_register_for_image_loads", &p);
+    return p(func);
+}
+
+void _dyld_register_for_bulk_image_loads(void (*func)(unsigned imageCount, const struct mach_header* mhs[], const char* paths[]))
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_register_for_bulk_image_loads(func);
+
+    DYLD_NO_LOCK_THIS_BLOCK;
+    typedef const void (*funcType)(void (*)(unsigned imageCount, const mach_header* mhs[], const char* paths[]));
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_register_for_bulk_image_loads", &p);
+    return p(func);
+}
+
+bool dyld_need_closure(const char* execPath, const char* dataContainerRootDir)
+{
+    return dyld3::dyld_need_closure(execPath, dataContainerRootDir);
+}
 
 bool dyld_process_is_restricted()
 {
@@ -1912,10 +1995,11 @@
 		return dyld3::dyld_process_is_restricted();
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static bool (*p)() = NULL;
+    typedef bool (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
 	
 	if(p == NULL)
-	    _dyld_func_lookup("__dyld_process_is_restricted", (void**)&p);
+	    dyld_func_lookup_and_resign("__dyld_process_is_restricted", &p);
 	return p();
 }
 
@@ -1925,26 +2009,62 @@
 		return dyld3::dyld_shared_cache_file_path();
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static const char* (*p)() = NULL;
+    typedef const char* (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
 	
 	if(p == NULL)
-	    _dyld_func_lookup("__dyld_shared_cache_file_path", (void**)&p);
+	    dyld_func_lookup_and_resign("__dyld_shared_cache_file_path", &p);
 	return p();
 }
 
+bool dyld_has_inserted_or_interposing_libraries()
+{
+	if ( gUseDyld3 )
+		return dyld3::dyld_has_inserted_or_interposing_libraries();
+
+	DYLD_NO_LOCK_THIS_BLOCK;
+    typedef bool (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if (p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_has_inserted_or_interposing_libraries", &p);
+	return p();
+}
+
+bool _dyld_has_fix_for_radar(const char *rdar) {
+    // There is no point in shimming this to dyld3, actual functionality can exist purely in libSystem for
+    // both dyld2 and dyld3.
+    return false;
+}
+
+
 void dyld_dynamic_interpose(const struct mach_header* mh, const struct dyld_interpose_tuple array[], size_t count)
 {
 	if ( gUseDyld3 )
 		return dyld3::dyld_dynamic_interpose(mh, array, count);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static void (*p)(const struct mach_header* mh, const struct dyld_interpose_tuple array[], size_t count) = NULL;
+    typedef void (*funcType)(const struct mach_header* mh, const struct dyld_interpose_tuple array[], size_t count);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
 
 	if (p == NULL)
-	    _dyld_func_lookup("__dyld_dynamic_interpose", (void**)&p);
+	    dyld_func_lookup_and_resign("__dyld_dynamic_interpose", &p);
 	p(mh, array, count);
 }
 
+// SPI called __fork
+void _dyld_atfork_prepare()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_atfork_prepare();
+}
+
+// SPI called __fork
+void _dyld_atfork_parent()
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_atfork_parent();
+}
 
 // SPI called __fork
 void _dyld_fork_child()
@@ -1953,10 +2073,11 @@
 		return dyld3::_dyld_fork_child();
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static void (*p)() = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_fork_child", (void**)&p);
+    typedef void (*funcType)();
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_fork_child", &p);
 	return p();
 }
 
@@ -1965,13 +2086,13 @@
 static void* mapStartOfCache(const char* path, size_t length)
 {
 	struct stat statbuf;
-	if ( ::stat(path, &statbuf) == -1 )
+	if ( dyld3::stat(path, &statbuf) == -1 )
 		return NULL;
 
-	if ( statbuf.st_size < length )
+	if ( (size_t)statbuf.st_size < length )
 		return NULL;
 
-	int cache_fd = ::open(path, O_RDONLY);
+	int cache_fd = dyld3::open(path, O_RDONLY, 0);
 	if ( cache_fd < 0 )
 		return NULL;
 
@@ -2004,7 +2125,7 @@
 			if ( strlcat(cachePath, entp->d_name, PATH_MAX) >= PATH_MAX )
 				continue;
 			if ( const dyld_cache_header* cacheHeader = (dyld_cache_header*)mapStartOfCache(cachePath, 0x00100000) ) {
-				if ( ::memcmp(cacheHeader->uuid, cacheUuid, 16) != 0 ) {
+				if ( (::memcmp(cacheHeader, "dyld_", 5) != 0) || (::memcmp(cacheHeader->uuid, cacheUuid, 16) != 0) ) {
 					// wrong uuid, unmap and keep looking
 					::munmap((void*)cacheHeader, 0x00100000);
 				}
@@ -2037,12 +2158,11 @@
 	}
 	else {
 		// look first is default location for cache files
-	#if	__IPHONE_OS_VERSION_MIN_REQUIRED
-		const char* defaultSearchDir = IPHONE_DYLD_SHARED_CACHE_DIR;
-	#else
-		const char* defaultSearchDir = MACOSX_DYLD_SHARED_CACHE_DIR;
-	#endif
-		cacheHeader = findCacheInDirAndMap(cacheUuid, defaultSearchDir);
+    #if TARGET_OS_IPHONE
+		cacheHeader = findCacheInDirAndMap(cacheUuid, IPHONE_DYLD_SHARED_CACHE_DIR);
+    #else
+		cacheHeader = findCacheInDirAndMap(cacheUuid, MACOSX_MRM_DYLD_SHARED_CACHE_DIR);
+    #endif
 		// if not there, look in extra search locations
 		if ( cacheHeader == NULL ) {
 			for (const char** p = extraSearchDirs; *p != NULL; ++p) {
@@ -2056,7 +2176,7 @@
 	if ( cacheHeader == NULL )
 		return -1;
 	
-	if ( cacheHeader->mappingOffset < sizeof(dyld_cache_header) ) {
+	if ( cacheHeader->mappingOffset <= __offsetof(dyld_cache_header, imagesTextOffset) ) {
 		// old cache without imagesText array
 		if ( needToUnmap )
 			::munmap((void*)cacheHeader, 0x00100000);
@@ -2101,10 +2221,11 @@
 		return dyld3::_dyld_is_memory_immutable(addr, length);
 
 	DYLD_NO_LOCK_THIS_BLOCK;
-    static bool (*p)(const void*, size_t) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_is_memory_immutable", (void**)&p);
+    typedef bool (*funcType)(const void*, size_t);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_is_memory_immutable", &p);
 	return p(addr, length);
 }
 
@@ -2117,14 +2238,119 @@
 		return dyld3::_dyld_objc_notify_register(mapped, init, unmapped);
 
 	DYLD_LOCK_THIS_BLOCK;
-    static bool (*p)(_dyld_objc_notify_mapped, _dyld_objc_notify_init, _dyld_objc_notify_unmapped) = NULL;
-
-	if(p == NULL)
-	    _dyld_func_lookup("__dyld_objc_notify_register", (void**)&p);
+    typedef bool (*funcType)(_dyld_objc_notify_mapped, _dyld_objc_notify_init, _dyld_objc_notify_unmapped);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+	if(p == NULL)
+	    dyld_func_lookup_and_resign("__dyld_objc_notify_register", &p);
 	p(mapped, init, unmapped);
 }
 
-
-
-
-
+void _dyld_missing_symbol_abort()
+{
+    return dyld3::_dyld_missing_symbol_abort();
+}
+
+const char* _dyld_get_objc_selector(const char* selName)
+{
+    // Check the shared cache table if it exists.
+    if ( gObjCOpt != nullptr ) {
+        if ( const objc_opt::objc_selopt_t* selopt = gObjCOpt->selopt() ) {
+            const char* name = selopt->get(selName);
+            if (name != nullptr)
+                return name;
+        }
+    }
+
+    if ( gUseDyld3 )
+        return dyld3::_dyld_get_objc_selector(selName);
+
+    return nullptr;
+}
+
+void _dyld_for_each_objc_class(const char* className,
+                           void (^callback)(void* classPtr, bool isLoaded, bool* stop)) {
+    if ( gUseDyld3 )
+        return dyld3::_dyld_for_each_objc_class(className, callback);
+}
+
+void _dyld_for_each_objc_protocol(const char* protocolName,
+                                  void (^callback)(void* protocolPtr, bool isLoaded, bool* stop)) {
+    if ( gUseDyld3 )
+        return dyld3::_dyld_for_each_objc_protocol(protocolName, callback);
+}
+
+void _dyld_register_driverkit_main(void (*mainFunc)(void))
+{
+    if ( gUseDyld3 )
+        return dyld3::_dyld_register_driverkit_main(mainFunc);
+
+    typedef bool (*funcType)(void *);
+    static funcType __ptrauth_dyld_function_ptr p = NULL;
+
+    if(p == NULL)
+        dyld_func_lookup_and_resign("__dyld_register_driverkit_main", &p);
+    p(reinterpret_cast<void *>(mainFunc));
+}
+
+// This is populated in the shared cache builder, so that the ranges are protected by __DATA_CONST
+// If we have a root, we can find this range in the shared cache libdyld at runtime
+typedef std::pair<const uint8_t*, const uint8_t*> ObjCConstantRange;
+
+#if TARGET_OS_OSX
+__attribute__((section(("__DATA, __objc_ranges"))))
+#else
+__attribute__((section(("__DATA_CONST, __objc_ranges"))))
+#endif
+__attribute__((used))
+static ObjCConstantRange gSharedCacheObjCConstantRanges[dyld_objc_string_kind + 1];
+
+static std::pair<const void*, uint64_t> getDyldCacheConstantRanges() {
+    const dyld_all_image_infos* allInfo = _dyld_get_all_image_infos();
+    if ( allInfo != nullptr  ) {
+        const DyldSharedCache* cache = (const DyldSharedCache*)(allInfo->sharedCacheBaseAddress);
+        if ( cache != nullptr ) {
+            return cache->getObjCConstantRange();
+        }
+    }
+    return { nullptr, 0 };
+}
+
+bool _dyld_is_objc_constant(DyldObjCConstantKind kind, const void* addr) {
+    assert(kind <= dyld_objc_string_kind);
+    // The common case should be that the value is in range, as this is a security
+    // check, so first test against the values in the struct.  If we have a root then
+    // we'll take the slow path later
+    if ( (addr >= gSharedCacheObjCConstantRanges[kind].first) && (addr < gSharedCacheObjCConstantRanges[kind].second) ) {
+        // Make sure that we are pointing at the start of a constant object, not in to the middle of it
+        uint64_t offset = (uint64_t)addr - (uint64_t)gSharedCacheObjCConstantRanges[kind].first;
+        return (offset % (uint64_t)DyldSharedCache::ConstantClasses::cfStringAtomSize) == 0;
+    }
+
+    // If we are in the shared cache, then the above check was sufficient, so this really isn't a valid constant address
+    extern void* __dso_handle;
+    const dyld3::MachOAnalyzer* ma = (const dyld3::MachOAnalyzer*)&__dso_handle;
+    if ( ma->inDyldCache() )
+        return false;
+
+    // We now know we are a root, so use the pointers in the shared cache libdyld version of gSharedCacheObjCConstantRanges
+    static std::pair<const void*, uint64_t> sharedCacheRanges = { nullptr, ~0ULL };
+
+    // FIXME: Should we fold this in as an inititalizer above?
+    // That would mean we need to link against somewhere to get ___cxa_guard_acquire/___cxa_guard_release
+    if ( sharedCacheRanges.second == ~0ULL )
+        sharedCacheRanges = getDyldCacheConstantRanges();
+
+    // We have the range of the section in libdyld in the shared cache, now get an array of ranges from it
+    uint64_t numRanges = sharedCacheRanges.second / sizeof(ObjCConstantRange);
+    if ( kind >= numRanges )
+        return false;
+
+    const ObjCConstantRange* rangeArrayBase = (const ObjCConstantRange*)sharedCacheRanges.first;
+    if ( (addr >= rangeArrayBase[kind].first) && (addr < rangeArrayBase[kind].second) ) {
+        // Make sure that we are pointing at the start of a constant object, not in to the middle of it
+        uint64_t offset = (uint64_t)addr - (uint64_t)rangeArrayBase[kind].first;
+        return (offset % (uint64_t)DyldSharedCache::ConstantClasses::cfStringAtomSize) == 0;
+    }
+    return false;
+}