dyld-635.2.tar.gz

[apple/dyld.git] / src / ImageLoaderMachO.cpp

diff --git a/src/ImageLoaderMachO.cpp b/src/ImageLoaderMachO.cpp
index d57bbd4613fa0d7c3488dd437d0557fe93438e49..f63769bce1b24faae113159ae297e50cb18cc266 100644 (file)
--- a/src/ImageLoaderMachO.cpp
+++ b/src/ImageLoaderMachO.cpp
@@ -1,6 +1,6 @@
 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
  *
 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
  *

- * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2010 Apple Inc. All rights reserved.

  *
  * @APPLE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_LICENSE_HEADER_START@
  * 


@@ -22,867 +22,1111 @@
  * @APPLE_LICENSE_HEADER_END@
  */
 
  * @APPLE_LICENSE_HEADER_END@
  */
 

+// work around until conformance work is complete rdar://problem/4508801
+#define __srr0 srr0 
+#define __eip  eip 
+#define __rip  rip 
+
+#define __STDC_LIMIT_MACROS

 #include <string.h>
 #include <fcntl.h>
 #include <string.h>
 #include <fcntl.h>

+#include <errno.h>

 #include <sys/types.h>
 #include <sys/types.h>

+#include <sys/fcntl.h>

 #include <sys/stat.h> 
 #include <sys/mman.h>
 #include <sys/stat.h> 
 #include <sys/mman.h>

-#include <mach/shared_memory_server.h>

 #include <mach/mach.h>
 #include <mach/thread_status.h>
 #include <mach-o/loader.h> 
 #include <mach/mach.h>
 #include <mach/thread_status.h>
 #include <mach-o/loader.h> 

-#include <mach-o/reloc.h> 

 #include <mach-o/nlist.h> 
 #include <sys/sysctl.h>
 #include <mach-o/nlist.h> 
 #include <sys/sysctl.h>

-#if __ppc__ || __ppc64__
-       #include <mach-o/ppc/reloc.h>
+#include <sys/syscall.h>
+#include <libkern/OSAtomic.h>
+#include <libkern/OSCacheControl.h>
+#include <stdint.h>
+#include <System/sys/codesign.h>
+
+#if __has_feature(ptrauth_calls)
+#include <ptrauth.h>

 #endif
 
 #endif
 

-#ifndef S_ATTR_SELF_MODIFYING_CODE
-  #define S_ATTR_SELF_MODIFYING_CODE 0x04000000
+#include "ImageLoaderMachO.h"
+#include "ImageLoaderMachOCompressed.h"
+#if SUPPORT_CLASSIC_MACHO
+#include "ImageLoaderMachOClassic.h"

 #endif
 #endif

+#include "mach-o/dyld_images.h"
+#include "Tracing.h"
+#include "dyld.h"

 
 

-#include "ImageLoaderMachO.h"
-#include "mach-o/dyld_gdb.h"
+// <rdar://problem/8718137> use stack guard random value to add padding between dylibs
+extern "C" long __stack_chk_guard;
+
+#ifndef LC_LOAD_UPWARD_DYLIB
+       #define LC_LOAD_UPWARD_DYLIB (0x23|LC_REQ_DYLD) /* load of dylib whose initializers run later */
+#endif

 
 

-// no header for this yet, rdar://problem/3850825
-extern "C" void sys_icache_invalidate(void *, size_t);
+#ifndef LC_VERSION_MIN_TVOS
+       #define LC_VERSION_MIN_TVOS 0x2F
+#endif

 
 

-// optimize strcmp for ppc
-#if __ppc__
-       #include <ppc_intrinsics.h>
-#else
-       #define astrcmp(a,b) strcmp(a,b)
+#ifndef LC_VERSION_MIN_WATCHOS
+       #define LC_VERSION_MIN_WATCHOS 0x30
+#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
 
 #endif
 

+#define LIBSYSTEM_DYLIB_PATH "/usr/lib/libSystem.B.dylib"
+

 // relocation_info.r_length field has value 3 for 64-bit executables and value 2 for 32-bit executables
 #if __LP64__
 // relocation_info.r_length field has value 3 for 64-bit executables and value 2 for 32-bit executables
 #if __LP64__

-       #define RELOC_SIZE 3

        #define LC_SEGMENT_COMMAND              LC_SEGMENT_64
        #define LC_ROUTINES_COMMAND             LC_ROUTINES_64
        #define LC_SEGMENT_COMMAND              LC_SEGMENT_64
        #define LC_ROUTINES_COMMAND             LC_ROUTINES_64

-       struct macho_header                             : public mach_header_64  {};
+       #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT

        struct macho_segment_command    : public segment_command_64  {};
        struct macho_section                    : public section_64  {};        
        struct macho_segment_command    : public segment_command_64  {};
        struct macho_section                    : public section_64  {};        

-       struct macho_nlist                              : public nlist_64  {};  

        struct macho_routines_command   : public routines_command_64  {};       
 #else
        struct macho_routines_command   : public routines_command_64  {};       
 #else

-       #define RELOC_SIZE 2

        #define LC_SEGMENT_COMMAND              LC_SEGMENT
        #define LC_ROUTINES_COMMAND             LC_ROUTINES
        #define LC_SEGMENT_COMMAND              LC_SEGMENT
        #define LC_ROUTINES_COMMAND             LC_ROUTINES

-       struct macho_header                             : public mach_header  {};
+       #define LC_SEGMENT_COMMAND_WRONG LC_SEGMENT_64

        struct macho_segment_command    : public segment_command {};
        struct macho_section                    : public section  {};   
        struct macho_segment_command    : public segment_command {};
        struct macho_section                    : public section  {};   

-       struct macho_nlist                              : public nlist  {};     

        struct macho_routines_command   : public routines_command  {};  
 #endif
 
        struct macho_routines_command   : public routines_command  {};  
 #endif
 

-       #define POINTER_RELOC GENERIC_RELOC_VANILLA
+uint32_t ImageLoaderMachO::fgSymbolTableBinarySearchs = 0;

 
 

-uint32_t ImageLoaderMachO::fgHintedBinaryTreeSearchs = 0;
-uint32_t ImageLoaderMachO::fgUnhintedBinaryTreeSearchs = 0;
-uint32_t ImageLoaderMachO::fgCountOfImagesWithWeakExports = 0;

 
 

+ImageLoaderMachO::ImageLoaderMachO(const macho_header* mh, const char* path, unsigned int segCount, 
+                                                                                                                               uint32_t segOffsets[], unsigned int libCount)
+ : ImageLoader(path, libCount), fCoveredCodeLength(0), fMachOData((uint8_t*)mh), fLinkEditBase(NULL), fSlide(0),
+       fEHFrameSectionOffset(0), fUnwindInfoSectionOffset(0), fDylibIDOffset(0), 
+fSegmentsCount(segCount), fIsSplitSeg(false), fInSharedCache(false),
+#if TEXT_RELOC_SUPPORT
+       fTextSegmentRebases(false),
+       fTextSegmentBinds(false),
+#endif
+#if __i386__
+       fReadOnlyImportSegment(false),
+#endif
+       fHasSubLibraries(false), fHasSubUmbrella(false), fInUmbrella(false), fHasDOFSections(false), fHasDashInit(false),
+       fHasInitializers(false), fHasTerminators(false), fNotifyObjC(false), fRetainForObjC(false), fRegisteredAsRequiresCoalescing(false), fOverrideOfCacheImageNum(0)
+{
+       fIsSplitSeg = ((mh->flags & MH_SPLIT_SEGS) != 0);        

 
 

-//#define LINKEDIT_USAGE_DEBUG 1
+       // construct SegmentMachO object for each LC_SEGMENT cmd using "placement new" to put 
+       // each SegmentMachO object in array at end of ImageLoaderMachO object
+       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, segIndex=0; i < cmd_count; ++i) {
+               if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
+                       const struct macho_segment_command* segCmd = (struct macho_segment_command*)cmd;
+                       // ignore zero-sized segments
+                       if ( segCmd->vmsize != 0 ) {
+                               // record offset of load command
+                               segOffsets[segIndex++] = (uint32_t)((uint8_t*)segCmd - fMachOData);
+                       }
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+       }

 
 

-#if LINKEDIT_USAGE_DEBUG
-       #include <set>
-       static std::set<uintptr_t> sLinkEditPageBuckets;
+}

 
 

-       namespace dyld {
-               extern ImageLoader*     findImageContainingAddress(const void* addr);
-       };
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+static uintptr_t pageAlign(uintptr_t value)
+{
+       return (value + 4095) & (-4096);
+}
+#endif

 
 

-       static void noteAccessedLinkEditAddress(const void* addr)
-       {
-               uintptr_t page = ((uintptr_t)addr) & (-4096);
-               sLinkEditPageBuckets.insert(page);
-               fprintf(stderr, "dyld: accessing page 0x%08lX in __LINKEDIT of %s\n", page, dyld::findImageContainingAddress(addr)->getPath());
+// determine if this mach-o file has classic or compressed LINKEDIT and number of segments it has
+void ImageLoaderMachO::sniffLoadCommands(const macho_header* mh, const char* path, bool inCache, bool* compressed,
+                                                                                       unsigned int* segCount, unsigned int* libCount, const LinkContext& context,
+                                                                                       const linkedit_data_command** codeSigCmd,
+                                                                                       const encryption_info_command** encryptCmd)
+{
+       *compressed = false;
+       *segCount = 0;
+       *libCount = 0;
+       *codeSigCmd = NULL;
+       *encryptCmd = NULL;
+
+       const uint32_t cmd_count = mh->ncmds;
+       const uint32_t sizeofcmds = mh->sizeofcmds;
+       if ( sizeofcmds > (MAX_MACH_O_HEADER_AND_LOAD_COMMANDS_SIZE-sizeof(macho_header)) )
+               dyld::throwf("malformed mach-o: load commands size (%u) > %u", sizeofcmds, MAX_MACH_O_HEADER_AND_LOAD_COMMANDS_SIZE);
+       if ( cmd_count > (sizeofcmds/sizeof(load_command)) )
+               dyld::throwf("malformed mach-o: ncmds (%u) too large to fit in sizeofcmds (%u)", cmd_count, sizeofcmds);
+       const struct load_command* const startCmds = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header));
+       const struct load_command* const endCmds = (struct load_command*)(((uint8_t*)mh) + sizeof(macho_header) + sizeofcmds);
+       const struct load_command* cmd = startCmds;
+       bool foundLoadCommandSegment = false;
+       const macho_segment_command* linkeditSegCmd = NULL;
+       const macho_segment_command* startOfFileSegCmd = NULL;
+       const dyld_info_command* dyldInfoCmd = NULL;
+       const symtab_command* symTabCmd = NULL;
+       const dysymtab_command* dynSymbTabCmd = NULL;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               uint32_t cmdLength = cmd->cmdsize;
+               const macho_segment_command* segCmd;
+               const dylib_command* dylibCmd;
+               if ( cmdLength < 8 ) {
+                       dyld::throwf("malformed mach-o image: load command #%d length (%u) too small in %s",
+                                                                                          i, cmdLength, path);
+               }
+               const struct load_command* const nextCmd = (const struct load_command*)(((char*)cmd)+cmdLength);
+               if ( (nextCmd > endCmds) || (nextCmd < cmd) ) {
+                       dyld::throwf("malformed mach-o image: load command #%d length (%u) would exceed sizeofcmds (%u) in %s",
+                                                                                          i, cmdLength, mh->sizeofcmds, path);
+               }
+               switch (cmd->cmd) {
+                       case LC_DYLD_INFO:
+                       case LC_DYLD_INFO_ONLY:
+                               if ( cmd->cmdsize != sizeof(dyld_info_command) )
+                                       throw "malformed mach-o image: LC_DYLD_INFO size wrong";
+                               dyldInfoCmd = (struct dyld_info_command*)cmd;
+                               *compressed = true;
+                               break;
+                       case LC_SEGMENT_COMMAND:
+                               segCmd = (struct macho_segment_command*)cmd;
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+                               // rdar://problem/19617624 allow unmapped segments on OSX (but not iOS)
+                               if ( ((segCmd->filesize) > pageAlign(segCmd->vmsize)) && (segCmd->vmsize != 0) )
+#else
+                               // <rdar://problem/19986776> dyld should support non-allocatable __LLVM segment
+                               if ( (segCmd->filesize > segCmd->vmsize) && ((segCmd->vmsize != 0) || ((segCmd->flags & SG_NORELOC) == 0)) )
+#endif
+                                   dyld::throwf("malformed mach-o image: segment load command %s filesize (0x%0lX) is larger than vmsize (0x%0lX)", segCmd->segname, (long)segCmd->filesize , (long)segCmd->vmsize );
+                               if ( cmd->cmdsize < sizeof(macho_segment_command) )
+                                       throw "malformed mach-o image: LC_SEGMENT size too small";
+                               if ( cmd->cmdsize != (sizeof(macho_segment_command) + segCmd->nsects * sizeof(macho_section)) )
+                                       throw "malformed mach-o image: LC_SEGMENT size wrong for number of sections";
+                               // ignore zero-sized segments
+                               if ( segCmd->vmsize != 0 )
+                                       *segCount += 1;
+                               if ( strcmp(segCmd->segname, "__LINKEDIT") == 0 ) {
+               #if TARGET_IPHONE_SIMULATOR
+                                       // Note: should check on all platforms that __LINKEDIT is read-only, but <rdar://problem/22637626&22525618>
+                                       if ( segCmd->initprot != VM_PROT_READ )
+                                               throw "malformed mach-o image: __LINKEDIT segment does not have read-only permissions";
+               #endif
+                                       if ( segCmd->fileoff ==  0 )
+                                               throw "malformed mach-o image: __LINKEDIT has fileoff==0 which overlaps mach_header";
+                                       if ( linkeditSegCmd != NULL )
+                                               throw "malformed mach-o image: multiple __LINKEDIT segments";
+                                       linkeditSegCmd = segCmd;
+                               }
+                               else {
+                                       if ( segCmd->initprot & 0xFFFFFFF8 )
+                                               dyld::throwf("malformed mach-o image: %s segment has invalid permission bits (0x%X) in initprot", segCmd->segname, segCmd->initprot);
+                                       if ( segCmd->maxprot & 0xFFFFFFF8 )
+                                               dyld::throwf("malformed mach-o image: %s segment has invalid permission bits (0x%X) in maxprot", segCmd->segname, segCmd->maxprot);
+                                       if ( (segCmd->initprot != 0) && ((segCmd->initprot & VM_PROT_READ) == 0) )
+                                               dyld::throwf("malformed mach-o image: %s segment is not mapped readable", segCmd->segname);
+                               }
+                if ( (segCmd->fileoff == 0) && (segCmd->filesize != 0) ) {
+                                       if ( (segCmd->initprot & VM_PROT_READ) == 0 )
+                                               dyld::throwf("malformed mach-o image: %s segment maps start of file but is not readable", segCmd->segname);
+                                       if ( (segCmd->initprot & VM_PROT_WRITE) == VM_PROT_WRITE ) {
+                                               if ( context.strictMachORequired )
+                                                       dyld::throwf("malformed mach-o image: %s segment maps start of file but is writable", segCmd->segname);
+                                       }
+                                       if ( segCmd->filesize < (sizeof(macho_header) + mh->sizeofcmds) )
+                                               dyld::throwf("malformed mach-o image: %s segment does not map all of load commands", segCmd->segname);
+                                       if ( startOfFileSegCmd != NULL )
+                                               dyld::throwf("malformed mach-o image: multiple segments map start of file: %s %s", startOfFileSegCmd->segname, segCmd->segname);
+                                       startOfFileSegCmd = segCmd;
+                               }
+                               if ( context.strictMachORequired ) {
+                                       uintptr_t vmStart   = segCmd->vmaddr;
+                                       uintptr_t vmSize    = segCmd->vmsize;
+                                       uintptr_t vmEnd     = vmStart + vmSize;
+                                       uintptr_t fileStart = segCmd->fileoff;
+                                       uintptr_t fileSize  = segCmd->filesize;
+                                       if ( (intptr_t)(vmSize) < 0 )
+                                               dyld::throwf("malformed mach-o image: segment load command %s vmsize too large in %s", segCmd->segname, path);
+                                       if ( vmStart > vmEnd )
+                                               dyld::throwf("malformed mach-o image: segment load command %s wraps around address space", segCmd->segname);
+                                       if ( vmSize != fileSize ) {
+                                               if ( segCmd->initprot == 0 ) {
+                                                       // allow: fileSize == 0 && initprot == 0                e.g. __PAGEZERO
+                                                       // allow: vmSize == 0 && initprot == 0                  e.g. __LLVM
+                                                       if ( (fileSize != 0) && (vmSize != 0) )
+                                                               dyld::throwf("malformed mach-o image: unaccessable segment %s has non-zero filesize and vmsize", segCmd->segname);
+                                               }
+                                               else {
+                                                       // allow: vmSize > fileSize && initprot != X  e.g. __DATA
+                                                       if ( vmSize < fileSize ) {
+                                                               dyld::throwf("malformed mach-o image: segment %s has vmsize < filesize", segCmd->segname);
+                                                       }
+                                                       if ( segCmd->initprot & VM_PROT_EXECUTE ) {
+                                                               dyld::throwf("malformed mach-o image: segment %s has vmsize != filesize and is executable", segCmd->segname);
+                                                       }
+                                               }
+                                       }
+                                       if ( inCache ) {
+                                               if ( (fileSize != 0) && (segCmd->initprot == (VM_PROT_READ | VM_PROT_EXECUTE)) ) {
+                                                       if ( foundLoadCommandSegment )
+                                                               throw "load commands in multiple segments";
+                                                       foundLoadCommandSegment = true;
+                                               }
+                                       }
+                                       else if ( (fileStart < mh->sizeofcmds) && (fileSize != 0) ) {
+                                               // <rdar://problem/7942521> all load commands must be in an executable segment
+                                               if ( (fileStart != 0) || (fileSize < (mh->sizeofcmds+sizeof(macho_header))) )
+                                                       dyld::throwf("malformed mach-o image: segment %s does not span all load commands", segCmd->segname); 
+                                               if ( segCmd->initprot != (VM_PROT_READ | VM_PROT_EXECUTE) ) 
+                                                       dyld::throwf("malformed mach-o image: load commands found in segment %s with wrong permissions", segCmd->segname); 
+                                               if ( foundLoadCommandSegment )
+                                                       throw "load commands in multiple segments";
+                                               foundLoadCommandSegment = true;
+                                       }
+
+                                       const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
+                                       const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
+                                       for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
+                                               if (!inCache && sect->offset != 0 && ((sect->offset + sect->size) > (segCmd->fileoff + segCmd->filesize)))
+                                                       dyld::throwf("malformed mach-o image: section %s,%s of '%s' exceeds segment %s booundary", sect->segname, sect->sectname, path, segCmd->segname);
+                                       }
+                               }
+                               break;
+                       case LC_SEGMENT_COMMAND_WRONG:
+                               dyld::throwf("malformed mach-o image: wrong LC_SEGMENT[_64] for architecture"); 
+                               break;
+                       case LC_LOAD_DYLIB:
+                       case LC_LOAD_WEAK_DYLIB:
+                       case LC_REEXPORT_DYLIB:
+                       case LC_LOAD_UPWARD_DYLIB:
+                               *libCount += 1;
+                               // fall thru
+                       case LC_ID_DYLIB:
+                               dylibCmd = (dylib_command*)cmd;
+                               if ( dylibCmd->dylib.name.offset > cmdLength )
+                                       dyld::throwf("malformed mach-o image: dylib load command #%d has offset (%u) outside its size (%u)", i, dylibCmd->dylib.name.offset, cmdLength);
+                               if ( (dylibCmd->dylib.name.offset + strlen((char*)dylibCmd + dylibCmd->dylib.name.offset) + 1) > cmdLength )
+                                       dyld::throwf("malformed mach-o image: dylib load command #%d string extends beyond end of load command", i);
+                               break;
+                       case LC_CODE_SIGNATURE:
+                               if ( cmd->cmdsize != sizeof(linkedit_data_command) )
+                                       throw "malformed mach-o image: LC_CODE_SIGNATURE size wrong";
+                               // <rdar://problem/22799652> only support one LC_CODE_SIGNATURE per image
+                               if ( *codeSigCmd != NULL )
+                                       throw "malformed mach-o image: multiple LC_CODE_SIGNATURE load commands";
+                               *codeSigCmd = (struct linkedit_data_command*)cmd;
+                               break;
+                       case LC_ENCRYPTION_INFO:
+                               if ( cmd->cmdsize != sizeof(encryption_info_command) )
+                                       throw "malformed mach-o image: LC_ENCRYPTION_INFO size wrong";
+                               // <rdar://problem/22799652> only support one LC_ENCRYPTION_INFO per image
+                               if ( *encryptCmd != NULL )
+                                       throw "malformed mach-o image: multiple LC_ENCRYPTION_INFO load commands";
+                               *encryptCmd = (encryption_info_command*)cmd;
+                               break;
+                       case LC_ENCRYPTION_INFO_64:
+                               if ( cmd->cmdsize != sizeof(encryption_info_command_64) )
+                                       throw "malformed mach-o image: LC_ENCRYPTION_INFO_64 size wrong";
+                               // <rdar://problem/22799652> only support one LC_ENCRYPTION_INFO_64 per image
+                               if ( *encryptCmd != NULL )
+                                       throw "malformed mach-o image: multiple LC_ENCRYPTION_INFO_64 load commands";
+                               *encryptCmd = (encryption_info_command*)cmd;
+                               break;
+                       case LC_SYMTAB:
+                               if ( cmd->cmdsize != sizeof(symtab_command) )
+                                       throw "malformed mach-o image: LC_SYMTAB size wrong";
+                               symTabCmd = (symtab_command*)cmd;
+                               break;
+                       case LC_DYSYMTAB:
+                               if ( cmd->cmdsize != sizeof(dysymtab_command) )
+                                       throw "malformed mach-o image: LC_DYSYMTAB size wrong";
+                               dynSymbTabCmd = (dysymtab_command*)cmd;
+                               break;
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+                       // <rdar://problem/26797345> error when loading iOS Simulator mach-o binary into macOS process
+                       case LC_VERSION_MIN_WATCHOS:
+                       case LC_VERSION_MIN_TVOS:
+                       case LC_VERSION_MIN_IPHONEOS:
+                               if ( !context.marzipan )
+                                       throw "mach-o, but built for simulator (not macOS)";
+                               break;
+#endif
+               }
+               cmd = nextCmd;

        }
        }

+
+       if ( context.strictMachORequired && !foundLoadCommandSegment )
+               throw "load commands not in a segment";
+       if ( linkeditSegCmd == NULL )
+               throw "malformed mach-o image: missing __LINKEDIT segment";
+       if ( !inCache && (startOfFileSegCmd == NULL) )
+               throw "malformed mach-o image: missing __TEXT segment that maps start of file";
+       // <rdar://problem/13145644> verify every segment does not overlap another segment
+       if ( context.strictMachORequired ) {
+               uintptr_t lastFileStart = 0;
+               uintptr_t linkeditFileStart = 0;
+               const struct load_command* cmd1 = startCmds;
+               for (uint32_t i = 0; i < cmd_count; ++i) {
+                       if ( cmd1->cmd == LC_SEGMENT_COMMAND ) {
+                               struct macho_segment_command* segCmd1 = (struct macho_segment_command*)cmd1;
+                               uintptr_t vmStart1   = segCmd1->vmaddr;
+                               uintptr_t vmEnd1     = segCmd1->vmaddr + segCmd1->vmsize;
+                               uintptr_t fileStart1 = segCmd1->fileoff;
+                               uintptr_t fileEnd1   = segCmd1->fileoff + segCmd1->filesize;
+
+                               if (fileStart1 > lastFileStart)
+                                       lastFileStart = fileStart1;
+
+                               if ( strcmp(&segCmd1->segname[0], "__LINKEDIT") == 0 ) {
+                                       linkeditFileStart = fileStart1;
+                               }
+
+                               const struct load_command* cmd2 = startCmds;
+                               for (uint32_t j = 0; j < cmd_count; ++j) {
+                                       if ( cmd2 == cmd1 )
+                                               continue;
+                                       if ( cmd2->cmd == LC_SEGMENT_COMMAND ) {
+                                               struct macho_segment_command* segCmd2 = (struct macho_segment_command*)cmd2;
+                                               uintptr_t vmStart2   = segCmd2->vmaddr;
+                                               uintptr_t vmEnd2     = segCmd2->vmaddr + segCmd2->vmsize;
+                                               uintptr_t fileStart2 = segCmd2->fileoff;
+                                               uintptr_t fileEnd2   = segCmd2->fileoff + segCmd2->filesize;
+                                               if ( ((vmStart2 <= vmStart1) && (vmEnd2 > vmStart1) && (vmEnd1 > vmStart1)) 
+                                               || ((vmStart2 >= vmStart1) && (vmStart2 < vmEnd1) && (vmEnd2 > vmStart2)) )
+                                                       dyld::throwf("malformed mach-o image: segment %s vm overlaps segment %s", segCmd1->segname, segCmd2->segname);
+                                               if ( ((fileStart2 <= fileStart1) && (fileEnd2 > fileStart1) && (fileEnd1 > fileStart1))
+                                                 || ((fileStart2 >= fileStart1) && (fileStart2 < fileEnd1) && (fileEnd2 > fileStart2)) )
+                                                       dyld::throwf("malformed mach-o image: segment %s file content overlaps segment %s", segCmd1->segname, segCmd2->segname); 
+                                       }
+                                       cmd2 = (const struct load_command*)(((char*)cmd2)+cmd2->cmdsize);
+                               }
+                       }
+                       cmd1 = (const struct load_command*)(((char*)cmd1)+cmd1->cmdsize);
+               }
+
+               if (lastFileStart != linkeditFileStart)
+                       dyld::throwf("malformed mach-o image: __LINKEDIT must be last segment");
+       }
+
+       // validate linkedit content
+       if  ( (dyldInfoCmd == NULL) && (symTabCmd == NULL) )
+               throw "malformed mach-o image: missing LC_SYMTAB or LC_DYLD_INFO";
+       if  ( dynSymbTabCmd == NULL )
+               throw "malformed mach-o image: missing LC_DYSYMTAB";
+
+       uint32_t  linkeditFileOffsetStart = (uint32_t)linkeditSegCmd->fileoff;
+       uint32_t  linkeditFileOffsetEnd = (uint32_t)linkeditSegCmd->fileoff + (uint32_t)linkeditSegCmd->filesize;
+
+       if ( !inCache && (dyldInfoCmd != NULL) && context.strictMachORequired ) {
+               // validate all LC_DYLD_INFO chunks fit in LINKEDIT and don't overlap
+               uint32_t offset = linkeditFileOffsetStart;
+               if ( dyldInfoCmd->rebase_size != 0 ) {
+                       if ( dyldInfoCmd->rebase_size & 0x80000000 )
+                               throw "malformed mach-o image: dyld rebase info size overflow";
+                       if ( dyldInfoCmd->rebase_off < offset )
+                               throw "malformed mach-o image: dyld rebase info underruns __LINKEDIT";
+                       offset = dyldInfoCmd->rebase_off + dyldInfoCmd->rebase_size;
+                       if ( offset > linkeditFileOffsetEnd )
+                               throw "malformed mach-o image: dyld rebase info overruns __LINKEDIT";
+               }
+               if ( dyldInfoCmd->bind_size != 0 ) {
+                       if ( dyldInfoCmd->bind_size & 0x80000000 )
+                               throw "malformed mach-o image: dyld bind info size overflow";
+                       if ( dyldInfoCmd->bind_off < offset )
+                               throw "malformed mach-o image: dyld bind info overlaps rebase info";
+                       offset = dyldInfoCmd->bind_off + dyldInfoCmd->bind_size;
+                       if ( offset > linkeditFileOffsetEnd )
+                               throw "malformed mach-o image: dyld bind info overruns __LINKEDIT";
+               }
+               if ( dyldInfoCmd->weak_bind_size != 0 ) {
+                       if ( dyldInfoCmd->weak_bind_size & 0x80000000 )
+                               throw "malformed mach-o image: dyld weak bind info size overflow";
+                       if ( dyldInfoCmd->weak_bind_off < offset )
+                               throw "malformed mach-o image: dyld weak bind info overlaps bind info";
+                       offset = dyldInfoCmd->weak_bind_off + dyldInfoCmd->weak_bind_size;
+                       if ( offset > linkeditFileOffsetEnd )
+                               throw "malformed mach-o image: dyld weak bind info overruns __LINKEDIT";
+               }
+               if ( dyldInfoCmd->lazy_bind_size != 0 ) {
+                       if ( dyldInfoCmd->lazy_bind_size & 0x80000000 )
+                               throw "malformed mach-o image: dyld lazy bind info size overflow";
+                       if ( dyldInfoCmd->lazy_bind_off < offset )
+                               throw "malformed mach-o image: dyld lazy bind info overlaps weak bind info";
+                       offset = dyldInfoCmd->lazy_bind_off + dyldInfoCmd->lazy_bind_size;
+                       if ( offset > linkeditFileOffsetEnd )
+                               throw "malformed mach-o image: dyld lazy bind info overruns __LINKEDIT";
+               }
+               if ( dyldInfoCmd->export_size != 0 ) {
+                       if ( dyldInfoCmd->export_size & 0x80000000 )
+                               throw "malformed mach-o image: dyld export info size overflow";
+                       if ( dyldInfoCmd->export_off < offset )
+                               throw "malformed mach-o image: dyld export info overlaps lazy bind info";
+                       offset = dyldInfoCmd->export_off + dyldInfoCmd->export_size;
+                       if ( offset > linkeditFileOffsetEnd )
+                               throw "malformed mach-o image: dyld export info overruns __LINKEDIT";
+               }
+       }
+
+       if ( symTabCmd != NULL ) {
+               // validate symbol table fits in LINKEDIT
+               if ( (symTabCmd->nsyms > 0) && (symTabCmd->symoff < linkeditFileOffsetStart) )
+                       throw "malformed mach-o image: symbol table underruns __LINKEDIT";
+               if ( symTabCmd->nsyms > 0x10000000 )
+                       throw "malformed mach-o image: symbol table too large";
+               uint32_t symbolsSize = symTabCmd->nsyms * sizeof(macho_nlist);
+               if ( symbolsSize > linkeditSegCmd->filesize )
+                       throw "malformed mach-o image: symbol table overruns __LINKEDIT";
+               if ( symTabCmd->symoff + symbolsSize < symTabCmd->symoff )
+                       throw "malformed mach-o image: symbol table size wraps";
+               if ( symTabCmd->symoff + symbolsSize > symTabCmd->stroff )
+                       throw "malformed mach-o image: symbol table overlaps symbol strings";
+               if ( symTabCmd->stroff + symTabCmd->strsize < symTabCmd->stroff )
+                       throw "malformed mach-o image: symbol string size wraps";
+               if ( symTabCmd->stroff + symTabCmd->strsize > linkeditFileOffsetEnd ) {
+                       // <rdar://problem/24220313> let old apps overflow as long as it stays within mapped page
+                       if ( context.strictMachORequired || (symTabCmd->stroff + symTabCmd->strsize > ((linkeditFileOffsetEnd + 4095) & (-4096))) )
+                               throw "malformed mach-o image: symbol strings overrun __LINKEDIT";
+               }
+               // validate indirect symbol table
+               if ( dynSymbTabCmd->nindirectsyms != 0 ) {
+                       if ( dynSymbTabCmd->indirectsymoff < linkeditFileOffsetStart )
+                               throw "malformed mach-o image: indirect symbol table underruns __LINKEDIT";
+                       if ( dynSymbTabCmd->nindirectsyms > 0x10000000 )
+                               throw "malformed mach-o image: indirect symbol table too large";
+                       uint32_t indirectTableSize = dynSymbTabCmd->nindirectsyms * sizeof(uint32_t);
+                       if ( indirectTableSize > linkeditSegCmd->filesize )
+                               throw "malformed mach-o image: indirect symbol table overruns __LINKEDIT";
+                       if ( dynSymbTabCmd->indirectsymoff + indirectTableSize < dynSymbTabCmd->indirectsymoff )
+                               throw "malformed mach-o image: indirect symbol table size wraps";
+                       if ( context.strictMachORequired && (dynSymbTabCmd->indirectsymoff + indirectTableSize > symTabCmd->stroff)  )
+                               throw "malformed mach-o image: indirect symbol table overruns string pool";
+               }
+               if ( (dynSymbTabCmd->nlocalsym > symTabCmd->nsyms) || (dynSymbTabCmd->ilocalsym > symTabCmd->nsyms) )
+                       throw "malformed mach-o image: indirect symbol table local symbol count exceeds total symbols";
+               if ( dynSymbTabCmd->ilocalsym + dynSymbTabCmd->nlocalsym < dynSymbTabCmd->ilocalsym  )
+                       throw "malformed mach-o image: indirect symbol table local symbol count wraps";
+               if ( (dynSymbTabCmd->nextdefsym > symTabCmd->nsyms) || (dynSymbTabCmd->iextdefsym > symTabCmd->nsyms) )
+                       throw "malformed mach-o image: indirect symbol table extern symbol count exceeds total symbols";
+               if ( dynSymbTabCmd->iextdefsym + dynSymbTabCmd->nextdefsym < dynSymbTabCmd->iextdefsym  )
+                       throw "malformed mach-o image: indirect symbol table extern symbol count wraps";
+               if ( (dynSymbTabCmd->nundefsym > symTabCmd->nsyms) || (dynSymbTabCmd->iundefsym > symTabCmd->nsyms) )
+                       throw "malformed mach-o image: indirect symbol table undefined symbol count exceeds total symbols";
+               if ( dynSymbTabCmd->iundefsym + dynSymbTabCmd->nundefsym < dynSymbTabCmd->iundefsym  )
+                       throw "malformed mach-o image: indirect symbol table undefined symbol count wraps";
+       }
+
+
+       // fSegmentsArrayCount is only 8-bits
+       if ( *segCount > 255 )
+               dyld::throwf("malformed mach-o image: more than 255 segments in %s", path);
+
+       // fSegmentsArrayCount is only 8-bits
+       if ( *libCount > 4095 )
+               dyld::throwf("malformed mach-o image: more than 4095 dependent libraries in %s", path);
+
+       if ( needsAddedLibSystemDepency(*libCount, mh) )
+               *libCount = 1;
+}
+
+
+
+// create image for main executable
+ImageLoader* ImageLoaderMachO::instantiateMainExecutable(const macho_header* mh, uintptr_t slide, const char* path, const LinkContext& context)
+{
+       //dyld::log("ImageLoader=%ld, ImageLoaderMachO=%ld, ImageLoaderMachOClassic=%ld, ImageLoaderMachOCompressed=%ld\n",
+       //      sizeof(ImageLoader), sizeof(ImageLoaderMachO), sizeof(ImageLoaderMachOClassic), sizeof(ImageLoaderMachOCompressed));
+       bool compressed;
+       unsigned int segCount;
+       unsigned int libCount;
+       const linkedit_data_command* codeSigCmd;
+       const encryption_info_command* encryptCmd;
+       sniffLoadCommands(mh, path, false, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
+       // instantiate concrete class based on content of load commands
+       if ( compressed ) 
+               return ImageLoaderMachOCompressed::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
+       else
+#if SUPPORT_CLASSIC_MACHO
+               return ImageLoaderMachOClassic::instantiateMainExecutable(mh, slide, path, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";

 #endif
 #endif

+}
+

 
 

-// only way to share initialization in C++
-void ImageLoaderMachO::init()
-{
-       fMachOData              = NULL;
-       fLinkEditBase   = NULL;
-       fSymbolTable    = NULL;
-       fStrings                = NULL;
-       fDynamicInfo    = NULL;
-       fSlide                  = 0;
-       fIsSplitSeg             = false;
-       fHasSubLibraries= false;
-       fHasSubUmbrella = false;
-       fDashInit               = NULL;
-       fModInitSection = NULL;
-       fModTermSection = NULL;
-       fDATAdyld               = NULL;
-       fImageNotifySection     = NULL;
-       fTwoLevelHints  = NULL;
-       fDylibID                = NULL;
-       fReExportThruFramework  = NULL;
-       fTextSegmentWithFixups = NULL;
+// create image by mapping in a mach-o file
+ImageLoader* ImageLoaderMachO::instantiateFromFile(const char* path, int fd, const uint8_t firstPages[], size_t firstPagesSize, uint64_t offsetInFat,
+                                                                       uint64_t lenInFat, const struct stat& info, const LinkContext& context)
+{
+       bool compressed;
+       unsigned int segCount;
+       unsigned int libCount;
+       const linkedit_data_command* codeSigCmd;
+       const encryption_info_command* encryptCmd;
+       sniffLoadCommands((const macho_header*)firstPages, path, false, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
+       // instantiate concrete class based on content of load commands
+       if ( compressed ) 
+               return ImageLoaderMachOCompressed::instantiateFromFile(path, fd, firstPages, firstPagesSize, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, encryptCmd, context);
+       else
+#if SUPPORT_CLASSIC_MACHO
+               return ImageLoaderMachOClassic::instantiateFromFile(path, fd, firstPages, firstPagesSize, offsetInFat, lenInFat, info, segCount, libCount, codeSigCmd, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif

 }
 
 }
 

-// create image by copying an in-memory mach-o file
-ImageLoaderMachO::ImageLoaderMachO(const char* moduleName, const struct mach_header* mh, uint64_t len, const LinkContext& context)
- : ImageLoader(moduleName)
+// create image by using cached mach-o file
+ImageLoader* ImageLoaderMachO::instantiateFromCache(const macho_header* mh, const char* path, long slide, const struct stat& info, const LinkContext& context)

 {
 {

-       // clean slate
-       this->init();
+       // instantiate right concrete class
+       bool compressed;
+       unsigned int segCount;
+       unsigned int libCount;
+       const linkedit_data_command* codeSigCmd;
+       const encryption_info_command* encryptCmd;
+       sniffLoadCommands(mh, path, true, &compressed, &segCount, &libCount, context, &codeSigCmd, &encryptCmd);
+       // instantiate concrete class based on content of load commands
+       if ( compressed ) 
+               return ImageLoaderMachOCompressed::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
+       else
+#if SUPPORT_CLASSIC_MACHO
+               return ImageLoaderMachOClassic::instantiateFromCache(mh, path, slide, info, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
+}
+
+// create image by copying an in-memory mach-o file
+ImageLoader* ImageLoaderMachO::instantiateFromMemory(const char* moduleName, const macho_header* mh, uint64_t len, const LinkContext& context)
+{
+       bool compressed;
+       unsigned int segCount;
+       unsigned int libCount;
+       const linkedit_data_command* sigcmd;
+       const encryption_info_command* encryptCmd;
+       sniffLoadCommands(mh, moduleName, false, &compressed, &segCount, &libCount, context, &sigcmd, &encryptCmd);
+       // instantiate concrete class based on content of load commands
+       if ( compressed ) 
+               return ImageLoaderMachOCompressed::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
+       else
+#if SUPPORT_CLASSIC_MACHO
+               return ImageLoaderMachOClassic::instantiateFromMemory(moduleName, mh, len, segCount, libCount, context);
+#else
+               throw "missing LC_DYLD_INFO load command";
+#endif
+}

 
 

-       // temporary use this buffer until TEXT is mapped in
-       fMachOData = (const uint8_t*)mh;

 
 

-       // create segments
-       this->instantiateSegments((const uint8_t*)mh);
-       
-       // map segments
-       if ( mh->filetype != MH_EXECUTE )
-               ImageLoader::mapSegments((const void*)mh, len, context);
-       
-       // get pointers to interesting things 
-       this->parseLoadCmds();
+int ImageLoaderMachO::crashIfInvalidCodeSignature()
+{
+       // Now that segments are mapped in, try reading from first executable segment.
+       // If code signing is enabled the kernel will validate the code signature
+       // when paging in, and kill the process if invalid.
+       for(unsigned int i=0; i < fSegmentsCount; ++i) {
+               if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
+                       // return read value to ensure compiler does not optimize away load
+                       int* p = (int*)segActualLoadAddress(i);
+                       return *p;
+               }
+       }
+       return 0;

 }
 
 
 }
 
 

-// create image by mapping in a mach-o file
-ImageLoaderMachO::ImageLoaderMachO(const char* path, int fd, const uint8_t firstPage[4096], uint64_t offsetInFat, 
-                                                                       uint64_t lenInFat, const struct stat& info, const LinkContext& context)
- : ImageLoader(path, offsetInFat, info)
-{      
-       // clean slate
-       this->init();
-
-       // read load commands
-       const unsigned int dataSize = sizeof(macho_header) + ((macho_header*)firstPage)->sizeofcmds;
-       uint8_t buffer[dataSize];
-       const uint8_t* fileData = firstPage;
-       if ( dataSize > 4096 ) {
-               // only read more if cmds take up more space than first page
-               fileData = buffer;
-               memcpy(buffer, firstPage, 4096);
-               pread(fd, &buffer[4096], dataSize-4096, offsetInFat+4096);
+void ImageLoaderMachO::parseLoadCmds(const LinkContext& context)
+{
+       // now that segments are mapped in, get real fMachOData, fLinkEditBase, and fSlide
+       for(unsigned int i=0; i < fSegmentsCount; ++i) {
+               // set up pointer to __LINKEDIT segment
+               if ( strcmp(segName(i),"__LINKEDIT") == 0 ) {
+       #if !__MAC_OS_X_VERSION_MIN_REQUIRED
+                       // <rdar://problem/42419336> historically, macOS never did this check
+                       if ( segFileOffset(i) > fCoveredCodeLength )
+                               dyld::throwf("cannot load '%s' (segment outside of code signature)", this->getShortName());
+       #endif
+                       fLinkEditBase = (uint8_t*)(segActualLoadAddress(i) - segFileOffset(i));
+               }
+#if TEXT_RELOC_SUPPORT
+               // __TEXT segment always starts at beginning of file and contains mach_header and load commands
+               if ( segExecutable(i) ) {
+                       if ( segHasRebaseFixUps(i) && (fSlide != 0) )
+                               fTextSegmentRebases = true;
+                       if ( segHasBindFixUps(i) )
+                               fTextSegmentBinds = true;
+               }
+#endif
+#if __i386__
+               if ( segIsReadOnlyImport(i) )
+                       fReadOnlyImportSegment = true;
+#endif
+               // some segment always starts at beginning of file and contains mach_header and load commands
+               if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
+                       fMachOData = (uint8_t*)(segActualLoadAddress(i));
+               }

        }
        
        }
        

-       // temporary use this buffer until TEXT is mapped in
-       fMachOData = fileData;
+       // keep count of prebound images with weak exports
+       if ( this->participatesInCoalescing() ) {
+               ++fgImagesRequiringCoalescing;
+               fRegisteredAsRequiresCoalescing = true;
+               if ( this->hasCoalescedExports() ) 
+                       ++fgImagesHasWeakDefinitions;
+       }
+
+       // keep count of images used in shared cache
+       if ( fInSharedCache )
+               ++fgImagesUsedFromSharedCache;
+
+       // walk load commands (mapped in at start of __TEXT segment)
+       const dyld_info_command* dyldInfo = NULL;
+       const macho_nlist* symbolTable = NULL;
+       const char* symbolTableStrings = NULL;
+       const struct load_command* firstUnknownCmd = NULL;
+       const struct version_min_command* minOSVersionCmd = NULL;
+       const dysymtab_command* dynSymbolTable = NULL;
+       const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+               switch (cmd->cmd) {
+                       case LC_SYMTAB:
+                               {
+                                       const struct symtab_command* symtab = (struct symtab_command*)cmd;
+                                       symbolTableStrings = (const char*)&fLinkEditBase[symtab->stroff];
+                                       symbolTable = (macho_nlist*)(&fLinkEditBase[symtab->symoff]);
+                               }
+                               break;
+                       case LC_DYSYMTAB:
+                               dynSymbolTable = (struct dysymtab_command*)cmd;
+                               break;
+                       case LC_SUB_UMBRELLA:
+                               fHasSubUmbrella = true;
+                               break;
+                       case LC_SUB_FRAMEWORK:
+                               fInUmbrella = true;
+                               break;
+                       case LC_SUB_LIBRARY:
+                               fHasSubLibraries = true;
+                               break;
+                       case LC_ROUTINES_COMMAND:
+                               fHasDashInit = true;
+                               break;
+                       case LC_DYLD_INFO:
+                       case LC_DYLD_INFO_ONLY:
+                               dyldInfo = (struct dyld_info_command*)cmd;
+                               break;
+                       case LC_SEGMENT_COMMAND:
+                               {
+                                       const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+                                       const bool isTextSeg = (strcmp(seg->segname, "__TEXT") == 0);
+               #if __i386__ && __MAC_OS_X_VERSION_MIN_REQUIRED
+                                       const bool isObjCSeg = (strcmp(seg->segname, "__OBJC") == 0);
+                                       if ( isObjCSeg )
+                                               fNotifyObjC = true;
+               #else
+                                       const bool isDataSeg = (strncmp(seg->segname, "__DATA", 6) == 0);
+               #endif
+                                       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_MOD_INIT_FUNC_POINTERS )
+                                                       fHasInitializers = true;
+                                               else if ( type == S_MOD_TERM_FUNC_POINTERS )
+                                                       fHasTerminators = true;
+                                               else if ( type == S_DTRACE_DOF )
+                                                       fHasDOFSections = true;
+                                               else if ( isTextSeg && (strcmp(sect->sectname, "__eh_frame") == 0) )
+                                                       fEHFrameSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
+                                               else if ( isTextSeg && (strcmp(sect->sectname, "__unwind_info") == 0) )
+                                                       fUnwindInfoSectionOffset = (uint32_t)((uint8_t*)sect - fMachOData);
+
+               #if __i386__ && __MAC_OS_X_VERSION_MIN_REQUIRED
+                                               else if ( isObjCSeg ) {
+                                                       if ( strcmp(sect->sectname, "__image_info") == 0 ) {
+                                                               const uint32_t* imageInfo = (uint32_t*)(sect->addr + fSlide);
+                                                               uint32_t flags = imageInfo[1];
+                                                               if ( (flags & 4) && (((macho_header*)fMachOData)->filetype != MH_EXECUTE) )
+                                                                       dyld::throwf("cannot load '%s' because Objective-C garbage collection is not supported", getPath());
+                                                       }
+                                                       else if ( ((macho_header*)fMachOData)->filetype == MH_DYLIB ) {
+                                                               fRetainForObjC = true;
+                                                       }
+                                               }
+               #else
+                                               else if ( isDataSeg && (strncmp(sect->sectname, "__objc_imageinfo", 16) == 0) ) {
+                       #if __MAC_OS_X_VERSION_MIN_REQUIRED
+                                                       const uint32_t* imageInfo = (uint32_t*)(sect->addr + fSlide);
+                                                       uint32_t flags = imageInfo[1];
+                                                       if ( (flags & 4) && (((macho_header*)fMachOData)->filetype != MH_EXECUTE) )
+                                                               dyld::throwf("cannot load '%s' because Objective-C garbage collection is not supported", getPath());
+                       #endif
+                                                       fNotifyObjC = true;
+                                               }
+                                               else if ( isDataSeg && (strncmp(sect->sectname, "__objc_", 7) == 0) && (((macho_header*)fMachOData)->filetype == MH_DYLIB) )
+                                                       fRetainForObjC = true;
+               #endif
+                                       }
+                               }
+                               break;
+                       case LC_TWOLEVEL_HINTS:
+                               // no longer supported
+                               break;
+                       case LC_ID_DYLIB:
+                               {
+                                       fDylibIDOffset = (uint32_t)((uint8_t*)cmd - fMachOData);
+                               }
+                               break;
+                       case LC_RPATH:
+                       case LC_LOAD_WEAK_DYLIB:
+                   case LC_REEXPORT_DYLIB:
+                       case LC_LOAD_UPWARD_DYLIB:
+                       case LC_MAIN:
+                               // do nothing, just prevent LC_REQ_DYLD exception from occuring
+                               break;
+                       case LC_VERSION_MIN_MACOSX:
+                       case LC_VERSION_MIN_IPHONEOS:
+                       case LC_VERSION_MIN_TVOS:
+                       case LC_VERSION_MIN_WATCHOS:
+                               minOSVersionCmd = (version_min_command*)cmd;
+                               break;
+                       default:
+                               if ( (cmd->cmd & LC_REQ_DYLD) != 0 ) {
+                                       if ( firstUnknownCmd == NULL )
+                                               firstUnknownCmd = cmd;
+                               }
+                               break;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+       }
+       if ( firstUnknownCmd != NULL ) {
+               if ( minOSVersionCmd != NULL )  {
+                       dyld::throwf("cannot load '%s' because it was built for OS version %u.%u (load command 0x%08X is unknown)", 
+                                                this->getShortName(),
+                                                minOSVersionCmd->version >> 16, ((minOSVersionCmd->version >> 8) & 0xff), 
+                                                firstUnknownCmd->cmd);
+               }
+               else {
+                       dyld::throwf("cannot load '%s' (load command 0x%08X is unknown)", this->getShortName(), firstUnknownCmd->cmd);
+               }
+       }

        
        

-       // the meaning of many fields changes in split seg mach-o files
-       fIsSplitSeg = ((((macho_header*)fileData)->flags & MH_SPLIT_SEGS) != 0) && (((macho_header*)fileData)->filetype == MH_DYLIB);   

        
        

-       // create segments
-       this->instantiateSegments(fileData);
+       if ( dyldInfo != NULL )
+               this->setDyldInfo(dyldInfo);
+       if ( symbolTable != NULL)
+               this->setSymbolTableInfo(symbolTable, symbolTableStrings, dynSymbolTable);

        
        

-       // map segments, except for main executable which is already mapped in by kernel
-       if ( ((macho_header*)fileData)->filetype != MH_EXECUTE )
-               this->mapSegments(fd, offsetInFat, lenInFat, info.st_size, context);
-                       
-       // get pointers to interesting things 
-       this->parseLoadCmds();

 }
 
 }
 

-ImageLoaderMachO::~ImageLoaderMachO()
+// don't do this work in destructor because we need object to be full subclass
+// for UnmapSegments() to work
+void ImageLoaderMachO::destroy()

 {
 {

-       // keep count of images with weak exports
-       if ( this->hasCoalescedExports() )
-               --fgCountOfImagesWithWeakExports;
+       // update count of images with weak exports
+       if ( fRegisteredAsRequiresCoalescing ) {
+               --fgImagesRequiringCoalescing;
+               if ( this->hasCoalescedExports() ) 
+                       --fgImagesHasWeakDefinitions;
+       }
+
+       // keep count of images used in shared cache
+       if ( fInSharedCache )
+               --fgImagesUsedFromSharedCache;
+               
+       // unmap image when done
+       UnmapSegments();

 }
 
 
 }
 
 

+unsigned int ImageLoaderMachO::segmentCount() const
+{
+       return fSegmentsCount;
+}

 
 

-void ImageLoaderMachO::instantiateSegments(const uint8_t* fileData)
+
+const macho_segment_command* ImageLoaderMachO::segLoadCommand(unsigned int segIndex) const

 {
 {

-       const uint32_t cmd_count = ((macho_header*)fileData)->ncmds;
-       const struct load_command* const cmds = (struct load_command*)&fileData[sizeof(macho_header)];
+       uint32_t* lcOffsets = this->segmentCommandOffsets();
+       uint32_t lcOffset =     lcOffsets[segIndex];
+       return (macho_segment_command*)(&fMachOData[lcOffset]);
+}

 
 

-       // construct Segment object for each LC_SEGMENT cmd and add to list
-       const struct load_command* cmd = cmds;
-       for (unsigned long i = 0; i < cmd_count; ++i) {
-               if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
-                       if ( (((struct macho_segment_command*)cmd)->vmsize != 0) || !fIsSplitSeg )
-                               fSegments.push_back(new SegmentMachO((struct macho_segment_command*)cmd, this, fileData));
-               }
-               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
-       }
+const char*    ImageLoaderMachO::segName(unsigned int segIndex) const
+{
+       return segLoadCommand(segIndex)->segname;

 }
 
 
 }
 
 

+uintptr_t ImageLoaderMachO::segSize(unsigned int segIndex) const
+{
+       return segLoadCommand(segIndex)->vmsize;
+}
+

 
 

-bool ImageLoaderMachO::segmentsMustSlideTogether() const 
+uintptr_t ImageLoaderMachO::segFileSize(unsigned int segIndex) const

 {
 {

-       return true;
+       return segLoadCommand(segIndex)->filesize;

 }
 
 }
 

-bool ImageLoaderMachO::segmentsCanSlide() const 
+
+bool ImageLoaderMachO::segHasTrailingZeroFill(unsigned int segIndex)

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->filetype == MH_DYLIB) || (mh->filetype == MH_BUNDLE) );
+       return ( segWriteable(segIndex) && (segSize(segIndex) > segFileSize(segIndex)) );

 }
 
 }
 

-bool ImageLoaderMachO::isBundle() const 
+
+uintptr_t ImageLoaderMachO::segFileOffset(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( mh->filetype == MH_BUNDLE );
+       return segLoadCommand(segIndex)->fileoff;

 }
 
 }
 

-bool ImageLoaderMachO::isDylib() const 
+
+bool ImageLoaderMachO::segReadable(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( mh->filetype == MH_DYLIB );
+       return ( (segLoadCommand(segIndex)->initprot & VM_PROT_READ) != 0);

 }
 
 }
 

-bool ImageLoaderMachO::forceFlat() const 
+
+bool ImageLoaderMachO::segWriteable(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->flags & MH_FORCE_FLAT) != 0 );
+       return ( (segLoadCommand(segIndex)->initprot & VM_PROT_WRITE) != 0);

 }
 
 }
 

-bool ImageLoaderMachO::usesTwoLevelNameSpace() const
+
+bool ImageLoaderMachO::segExecutable(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->flags & MH_TWOLEVEL) != 0 );
+       return ( (segLoadCommand(segIndex)->initprot & VM_PROT_EXECUTE) != 0);

 }
 
 }
 

-bool ImageLoaderMachO::isPrebindable() const 
+
+bool ImageLoaderMachO::segUnaccessible(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->flags & MH_PREBOUND) != 0 );
+       return (segLoadCommand(segIndex)->initprot == 0);

 }
 
 }
 

-bool ImageLoaderMachO::hasCoalescedExports() const 
+bool ImageLoaderMachO::segHasPreferredLoadAddress(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->flags & MH_WEAK_DEFINES) != 0 );
+       return (segLoadCommand(segIndex)->vmaddr != 0);

 }
 
 }
 

-bool ImageLoaderMachO::needsCoalescing() const 
+uintptr_t ImageLoaderMachO::segPreferredLoadAddress(unsigned int segIndex) const

 {
 {

-       const macho_header* mh = (macho_header*)fMachOData;
-       return ( (mh->flags & MH_BINDS_TO_WEAK) != 0 );
+       return segLoadCommand(segIndex)->vmaddr;

 }
 
 }
 

-#if !__LP64__   // split segs not supported for 64-bits
+uintptr_t ImageLoaderMachO::segActualLoadAddress(unsigned int segIndex) const
+{
+       return segLoadCommand(segIndex)->vmaddr + fSlide;
+}

 
 

-#if 1 // hack until kernel headers and glue are in system
-struct _shared_region_mapping_np {
-    mach_vm_address_t   address;
-    mach_vm_size_t      size;
-    mach_vm_offset_t    file_offset;
-       vm_prot_t               max_prot;   /* read/write/execute/COW/ZF */
-       vm_prot_t               init_prot;  /* read/write/execute/COW/ZF */
-};
-struct _shared_region_range_np {
-    mach_vm_address_t   address;
-    mach_vm_size_t      size;
-};
-               
-// Called by dyld.  
-// Requests the kernel to map a number of regions from the fd into the
-// shared sections address range (0x90000000-0xAFFFFFFF).
-// If shared_region_make_private_np() has not been called by this process, 
-// the file mapped in is seen in the address space of all processes that
-// participate in using the shared region. 
-// If shared_region_make_private_np() _has_ been called by this process, 
-// the file mapped in is only seen by this process.
-// If the slide parameter is not NULL and then regions cannot be mapped
-// as requested, the kernel will try to map the file in at a different
-// address in the shared region and return the distance slid. 
-// If the mapping requesting cannot be fulfilled, returns non-zero.
-static int 
-_shared_region_map_file_np(
-       int fd,                                                 // file descriptor to map into shared region
-       unsigned int regionCount,               // number of entres in array of regions
-       const _shared_region_mapping_np regions[],      // the array of regions to map
-       uint64_t* slide)                                        // the amount all regions were slid,  NULL means don't attempt to slide
-{
-       //fprintf(stderr, "%s(%i, %u, %8p, %8p)\n", __func__, fd, regionCount, regions, slide);
-       //for ( unsigned int i=0; i < regionCount; ++i) {
-       //      fprintf(stderr, "\taddress=0x%08llX, size=0x%08llX\n", regions[i].address, regions[i].size);
-       //}
-       int r = syscall(299, fd, regionCount, regions, slide);
-//     if(0 != r)
-//             fprintf(stderr, "%s(%i, %u, %8p, %8p) errno=%i (%s)\n", __func__, fd, regionCount, regions, slide, errno, strerror(errno));
-    return r;
-}
-// Called by dyld if shared_region_map_file() fails.
-// Requests the kernel to take this process out of using the shared region.
-// The specified ranges are created as private copies from the shared region for this process.
-static int 
-_shared_region_make_private_np(
-       unsigned int rangeCount,                                // number of entres in array of msrp_range
-       const _shared_region_range_np ranges[]) // the array of shared regions to make private
-{
-       //fprintf(stderr, "%s(%u, %8p)\n", __func__, rangeCount, ranges);
-       int r = syscall(300, rangeCount, ranges);
-//     if(0 != r)
-//             fprintf(stderr, "%s(%u, %8p) errno=%i (%s)\n", __func__, rangeCount, ranges, errno, strerror(errno));
-    return r;
-}
-#define KERN_SHREG_PRIVATIZABLE        54
-#endif // hack until kernel headers and glue are in system
-
-static uintptr_t sNextAltLoadAddress 
-#if __ppc_
-       = 0xC0000000;
-#else
-       = 0;
-#endif

 
 

-static int 
-_shared_region_map_file_with_mmap(
-       int fd,                                                 // file descriptor to map into shared region
-       unsigned int regionCount,               // number of entres in array of regions
-       const _shared_region_mapping_np regions[])      // the array of regions to map
+uintptr_t ImageLoaderMachO::segActualEndAddress(unsigned int segIndex) const

 {
 {

-       // map in each region
-       for(unsigned int i=0; i < regionCount; ++i) {
-               void* mmapAddress = (void*)(uintptr_t)(regions[i].address);
-               size_t size = regions[i].size;
-               if ( (regions[i].init_prot & VM_PROT_ZF) != 0 ) {
-                       // do nothing already vm_allocate() which zero fills
-               }
-               else {
-                       int protection = 0;
-                       if ( regions[i].init_prot & VM_PROT_EXECUTE )
-                               protection   |= PROT_EXEC;
-                       if ( regions[i].init_prot & VM_PROT_READ )
-                               protection   |= PROT_READ;
-                       if ( regions[i].init_prot & VM_PROT_WRITE )
-                               protection   |= PROT_WRITE;
-                       off_t offset = regions[i].file_offset;
-                       //fprintf(stderr, "mmap(%p, 0x%08lX, block=0x%08X, %s\n", mmapAddress, size, biggestDiff, fPath);
-                       mmapAddress = mmap(mmapAddress, size, protection, MAP_FILE | MAP_FIXED | MAP_PRIVATE, fd, offset);
-                       if ( mmapAddress == ((void*)(-1)) )
-                               throw "mmap error";
-               }
-       }
-       
-       return 0;
+       return segActualLoadAddress(segIndex) + segSize(segIndex);

 }
 
 }
 

-
-static
-bool
-hasSharedRegionMapFile(void)
-{
-       int     mib[CTL_MAXNAME];
-       int     value = 0;
-       size_t  size;
-
-       mib[0] = CTL_KERN;
-       mib[1] = KERN_SHREG_PRIVATIZABLE;
-       size = sizeof (int);
-       if (sysctl(mib, 2, &value, &size, NULL, 0) != 0) {
-               value = 0;
-       }
-
-       return 0 != value;
-}
-
-int
-ImageLoaderMachO::sharedRegionMapFilePrivateOutside(int fd,
-                                                                                                       uint64_t offsetInFat,
-                                                                                                       uint64_t lenInFat,
-                                                                                                       uint64_t fileLen,
-                                                                                                       const LinkContext& context)
-{
-       const unsigned int segmentCount = fSegments.size();
-       const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
-       const unsigned int regionCount = segmentCount+extraZeroFillEntries;
-       _shared_region_mapping_np regions[regionCount];
-       initMappingTable(offsetInFat, regions);
-       int r = -1;
-               // find space somewhere to allocate split seg
-               bool foundRoom = false;
-               vm_size_t biggestDiff = 0;
-               while ( ! foundRoom ) {
-                       foundRoom = true;
-                       for(unsigned int i=0; i < regionCount; ++i) {
-                               vm_address_t addr = sNextAltLoadAddress + regions[i].address - regions[0].address;
-                               vm_size_t size = regions[i].size ;
-                               r = vm_allocate(mach_task_self(), &addr, size, false /*only this range*/);
-                               if ( 0 != r ) {
-                                       // no room here, deallocate what has succeeded so far
-                                       for(unsigned int j=0; j < i; ++j) {
-                                               vm_address_t addr = sNextAltLoadAddress + regions[j].address - regions[0].address;
-                                               vm_size_t size = regions[j].size ;
-                                               (void)vm_deallocate(mach_task_self(), addr, size);
-                                       }
-                                       sNextAltLoadAddress += 0x00100000;  // skip ahead 1MB and try again
-                                       if ( (sNextAltLoadAddress & 0xF0000000) == 0x90000000 )
-                                               sNextAltLoadAddress = 0xB0000000;
-                                       if ( (sNextAltLoadAddress & 0xF0000000) == 0xF0000000 )
-                                               throw "can't map split seg anywhere";
-                                       foundRoom = false;
-                                       break;
-                               }
-                               vm_size_t high = (regions[i].address + size - regions[0].address) & 0x0FFFFFFF;
-                               if ( high > biggestDiff )
-                                       biggestDiff = high;
-                       }
-               }
-               
-               // map in each region
-               uintptr_t slide = sNextAltLoadAddress - regions[0].address;
-               this->setSlide(slide);
-               for(unsigned int i=0; i < regionCount; ++i) {
-                       if ( (regions[i].init_prot & VM_PROT_ZF) != 0 ) {
-                               // do nothing vm_allocate() zero-fills by default
+bool ImageLoaderMachO::segHasRebaseFixUps(unsigned int segIndex) const
+{
+#if TEXT_RELOC_SUPPORT
+       // scan sections for fix-up bit
+       const macho_segment_command* segCmd = segLoadCommand(segIndex);
+       const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
+       const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
+       for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
+               if ( (sect->flags & S_ATTR_LOC_RELOC) != 0 )
+                       return true;
+       }
+#endif
+       return false;
+}
+
+bool ImageLoaderMachO::segHasBindFixUps(unsigned int segIndex) const
+{
+#if TEXT_RELOC_SUPPORT
+       // scan sections for fix-up bit
+       const macho_segment_command* segCmd = segLoadCommand(segIndex);
+       const struct macho_section* const sectionsStart = (struct macho_section*)((char*)segCmd + sizeof(struct macho_segment_command));
+       const struct macho_section* const sectionsEnd = &sectionsStart[segCmd->nsects];
+       for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
+               if ( (sect->flags & S_ATTR_EXT_RELOC) != 0 )
+                       return true;
+       }
+#endif
+       return false;
+}
+
+#if __i386__
+bool ImageLoaderMachO::segIsReadOnlyImport(unsigned int segIndex) const
+{
+       const macho_segment_command* segCmd = segLoadCommand(segIndex);
+       return (    (segCmd->initprot & VM_PROT_EXECUTE) 
+                       && ((segCmd->initprot & VM_PROT_WRITE) == 0) 
+                       && (strcmp(segCmd->segname, "__IMPORT") == 0) );
+}
+#endif
+
+
+void ImageLoaderMachO::UnmapSegments()
+{
+       // usually unmap image when done
+       if ( ! this->leaveMapped() && (this->getState() >= dyld_image_state_mapped) ) {
+               // unmap TEXT segment last because it contains load command being inspected
+               unsigned int textSegmentIndex = 0;
+               for(unsigned int i=0; i < fSegmentsCount; ++i) {
+                       //dyld::log("unmap %s at 0x%08lX\n", seg->getName(), seg->getActualLoadAddress(this));
+                       if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) ) {
+                               textSegmentIndex = i;

                        }
                        else {
                        }
                        else {

-                               void* mmapAddress = (void*)(uintptr_t)(regions[i].address + slide);
-                               size_t size = regions[i].size;
-                               int protection = 0;
-                               if ( regions[i].init_prot & VM_PROT_EXECUTE )
-                                       protection   |= PROT_EXEC;
-                               if ( regions[i].init_prot & VM_PROT_READ )
-                                       protection   |= PROT_READ;
-                               if ( regions[i].init_prot & VM_PROT_WRITE )
-                                       protection   |= PROT_WRITE;
-                               off_t offset = regions[i].file_offset;
-                               //fprintf(stderr, "mmap(%p, 0x%08lX, block=0x%08X, %s\n", mmapAddress, size, biggestDiff, fPath);
-                               mmapAddress = mmap(mmapAddress, size, protection, MAP_FILE | MAP_FIXED | MAP_PRIVATE, fd, offset);
-                               if ( mmapAddress == ((void*)(-1)) )
-                                       throw "mmap error";
+                               // update stats
+                               --ImageLoader::fgTotalSegmentsMapped;
+                               ImageLoader::fgTotalBytesMapped -= segSize(i);
+                               munmap((void*)segActualLoadAddress(i), segSize(i));

                        }
                }
                        }
                }

-               // set so next maps right after this one
-               sNextAltLoadAddress += biggestDiff; 
-               sNextAltLoadAddress = (sNextAltLoadAddress + 4095) & (-4096);
-               
-               // logging
-               if ( context.verboseMapping ) {
-                       fprintf(stderr, "dyld: Mapping split-seg outside shared region, slid by 0x%08lX %s\n", this->fSlide, this->getPath());
-                       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-                               Segment* seg = fSegments[segIndex];
-                               const _shared_region_mapping_np* entry = &regions[entryIndex];
-                               if ( (entry->init_prot & VM_PROT_ZF) == 0 ) 
-                                       fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                       seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
-                               if ( entryIndex < (regionCount-1) ) {
-                                       const _shared_region_mapping_np* nextEntry = &regions[entryIndex+1];
-                                       if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
-                                               uint64_t segOffset = nextEntry->address - entry->address;
-                                               fprintf(stderr, "%18s at 0x%08lX->0x%08lX (zerofill)\n",
-                                                               seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
-                                               ++entryIndex;
-                                       }
+               // now unmap TEXT
+               --ImageLoader::fgTotalSegmentsMapped;
+               ImageLoader::fgTotalBytesMapped -= segSize(textSegmentIndex);
+               munmap((void*)segActualLoadAddress(textSegmentIndex), segSize(textSegmentIndex));
+       }
+}
+
+
+// prefetch __DATA/__OBJC pages during launch, but not for dynamically loaded code
+void ImageLoaderMachO::preFetchDATA(int fd, uint64_t offsetInFat, const LinkContext& context)
+{
+       if ( context.linkingMainExecutable ) {
+               for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+                       if ( segWriteable(i) && (segFileSize(i) > 0) ) {
+                               // prefetch writable segment that have mmap'ed regions
+                               radvisory advice;
+                               advice.ra_offset = offsetInFat + segFileOffset(i);
+                               advice.ra_count = (int)segFileSize(i);
+                               // limit prefetch to 1MB (256 pages)
+                               if ( advice.ra_count > 1024*1024 )
+                                       advice.ra_count = 1024*1024;
+                               // don't prefetch single pages, let them fault in
+                               fgTotalBytesPreFetched += advice.ra_count;
+                               fcntl(fd, F_RDADVISE, &advice);
+                               if ( context.verboseMapping ) {
+                                       dyld::log("%18s prefetching 0x%0lX -> 0x%0lX\n", 
+                                               segName(i), segActualLoadAddress(i), segActualLoadAddress(i)+advice.ra_count-1);

                                }
                        }
                }
                                }
                        }
                }

-               
-               return r;
+       }

 }
 
 
 }
 
 

-void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
+bool ImageLoaderMachO::segmentsMustSlideTogether() const 

 {
 {

-       enum SharedRegionState
-       {
-               kSharedRegionStartState = 0,
-               kSharedRegionLoadFileState,
-               kSharedRegionMapFileState,
-               kSharedRegionMapFilePrivateState,
-               kSharedRegionMapFilePrivateMMapState,
-               kSharedRegionMapFilePrivateOutsideState,
-       };
-       static SharedRegionState sSharedRegionState = kSharedRegionStartState;
+       return true;
+}

 
 

-       // non-split segment libraries handled by super class
-       if ( !fIsSplitSeg )
-               return ImageLoader::mapSegments(fd, offsetInFat, lenInFat, fileLen, context);
-       
-       if ( kSharedRegionStartState == sSharedRegionState ) {
-               if ( hasSharedRegionMapFile() ) {
-                       if ( context.slideAndPackDylibs ) { 
-                               sharedRegionMakePrivate(context);
-                               // remove underlying submap and block out 0x90000000 to 0xAFFFFFFF
-                               vm_address_t addr = (vm_address_t)0x90000000;
-                               vm_deallocate(mach_task_self(), addr, 0x20000000);
-                               vm_allocate(mach_task_self(), &addr, 0x20000000, false);
-                               sSharedRegionState = kSharedRegionMapFilePrivateMMapState;
-                       }
-                       else if ( context.sharedRegionMode == kUsePrivateSharedRegion ) { 
-                               sharedRegionMakePrivate(context);
-                               sSharedRegionState = kSharedRegionMapFilePrivateState;
-                       }
-                       else if ( context.sharedRegionMode == kDontUseSharedRegion ) {
-                               sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
-                       }
-                       else {
-                               sSharedRegionState = kSharedRegionMapFileState;
-                       }
-               }
-               else {
-                       sSharedRegionState = kSharedRegionLoadFileState;
-               }
-       }
-       
-       if ( kSharedRegionLoadFileState == sSharedRegionState ) {
-               if ( 0 != sharedRegionLoadFile(fd, offsetInFat, lenInFat, fileLen, context) ) {
-                       sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
-               }
-       }
-       else
-       if ( kSharedRegionMapFileState == sSharedRegionState ) {
-               if ( 0 != sharedRegionMapFile(fd, offsetInFat, lenInFat, fileLen, context) ) {
-                       sharedRegionMakePrivate(context);
-                       sSharedRegionState = kSharedRegionMapFilePrivateState;
-               }
-       }
-       
-       if ( (kSharedRegionMapFilePrivateState == sSharedRegionState) || (kSharedRegionMapFilePrivateMMapState == sSharedRegionState) ) {
-               if ( 0 != sharedRegionMapFilePrivate(fd, offsetInFat, lenInFat, fileLen, context, (kSharedRegionMapFilePrivateMMapState == sSharedRegionState)) ) {
-                       sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
-               }
-       }
-       
-       if ( kSharedRegionMapFilePrivateOutsideState == sSharedRegionState ) {
-               if ( 0 != sharedRegionMapFilePrivateOutside(fd, offsetInFat, lenInFat, fileLen, context) ) {
-                       throw "mapping error";
-               }
-       }
+bool ImageLoaderMachO::segmentsCanSlide() const 
+{
+       return (this->isDylib() || this->isBundle() || this->isPositionIndependentExecutable());

 }
 
 }
 

-unsigned int
-ImageLoaderMachO::getExtraZeroFillEntriesCount()
+bool ImageLoaderMachO::isBundle() const 

 {
 {

-       // calculate mapping entries
-       const unsigned int segmentCount = fSegments.size();
-       unsigned int extraZeroFillEntries = 0;
-       for(unsigned int i=0; i < segmentCount; ++i){
-               Segment* seg = fSegments[i];
-               if ( seg->hasTrailingZeroFill() )
-                       ++extraZeroFillEntries;
-       }
-       
-       return extraZeroFillEntries;
-}
-
-void
-ImageLoaderMachO::initMappingTable(uint64_t offsetInFat,
-                                                                  _shared_region_mapping_np *mappingTable)
-{
-       unsigned int segmentCount = fSegments.size();
-       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-               Segment* seg = fSegments[segIndex];
-               _shared_region_mapping_np* entry = &mappingTable[entryIndex];
-               entry->address                  = seg->getActualLoadAddress();
-               entry->size                             = seg->getFileSize();
-               entry->file_offset              = seg->getFileOffset() + offsetInFat;
-               entry->init_prot                = VM_PROT_NONE;
-               if ( !seg->unaccessible() ) {
-                       if ( seg->executable() )
-                               entry->init_prot   |= VM_PROT_EXECUTE;
-                       if ( seg->readable() )
-                               entry->init_prot   |= VM_PROT_READ;
-                       if ( seg->writeable() )
-                               entry->init_prot   |= VM_PROT_WRITE | VM_PROT_COW;
-               }
-               entry->max_prot                 = entry->init_prot;
-               if ( seg->hasTrailingZeroFill() ) {
-                       _shared_region_mapping_np* zfentry = &mappingTable[++entryIndex];
-                       zfentry->address                = entry->address + seg->getFileSize();
-                       zfentry->size                   = seg->getSize() - seg->getFileSize();
-                       zfentry->file_offset    = 0;
-                       zfentry->init_prot              = entry->init_prot | VM_PROT_COW | VM_PROT_ZF;
-                       zfentry->max_prot               = zfentry->init_prot;
-               }
-       }
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( mh->filetype == MH_BUNDLE );

 }
 }

-       
-int
-ImageLoaderMachO::sharedRegionMakePrivate(const LinkContext& context)
+
+bool ImageLoaderMachO::isDylib() const 

 {
 {

-       if ( context.verboseMapping )
-               fprintf(stderr, "dyld: making shared regions private\n");
-
-       // shared mapping failed, so make private copy of shared region and try mapping private
-       RegionsVector allRegions;
-       context.getAllMappedRegions(allRegions);
-       std::vector<_shared_region_range_np> splitSegRegions;
-       const unsigned int allRegiontCount = allRegions.size();
-       for(unsigned int i=0; i < allRegiontCount; ++i){
-               MappedRegion region = allRegions[i];
-               uint8_t highByte = region.address >> 28;
-               if ( (highByte == 9) || (highByte == 0xA) ) {
-                       _shared_region_range_np splitRegion;
-                       splitRegion.address = region.address;
-                       splitRegion.size = region.size;
-                       splitSegRegions.push_back(splitRegion);
-               }
-       }
-       int result = _shared_region_make_private_np(splitSegRegions.size(), &splitSegRegions[0]);
-       // notify gdb or other lurkers that this process is no longer using the shared region
-       dyld_all_image_infos.processDetachedFromSharedRegion = true;
-       return result;
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( mh->filetype == MH_DYLIB );

 }
 
 }
 

-int
-ImageLoaderMachO::sharedRegionMapFile(int fd,
-                                         uint64_t offsetInFat,
-                                         uint64_t lenInFat,
-                                         uint64_t fileLen,
-                                         const LinkContext& context)
-{
-       // build table of segments to map
-       const unsigned int segmentCount = fSegments.size();
-       const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
-       const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
-       _shared_region_mapping_np mappingTable[mappingTableCount];
-       initMappingTable(offsetInFat, mappingTable);
-//     uint64_t slide;
-       uint64_t *slidep = NULL;
-
-       // try to map it in shared
-       int r = _shared_region_map_file_np(fd, mappingTableCount, mappingTable, slidep);
-       if ( 0 == r ) {
-               if(NULL != slidep && 0 != *slidep) {
-                       // update with actual load addresses
-               }
-               if ( context.verboseMapping ) {
-                       fprintf(stderr, "dyld: Mapping split-seg shared %s\n", this->getPath());
-                       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-                               Segment* seg = fSegments[segIndex];
-                               const _shared_region_mapping_np* entry = &mappingTable[entryIndex];
-                               if ( (entry->init_prot & VM_PROT_ZF) == 0 ) 
-                                       fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                       seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
-                               if ( entryIndex < (mappingTableCount-1) ) {
-                                       const _shared_region_mapping_np* nextEntry = &mappingTable[entryIndex+1];
-                                       if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
-                                               uint64_t segOffset = nextEntry->address - entry->address;
-                                               fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                               seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
-                                               ++entryIndex;
-                                       }
-                               }
-                       }
-               }
-       }
-       return r;
+bool ImageLoaderMachO::isExecutable() const 
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( mh->filetype == MH_EXECUTE );

 }
 
 }
 

+bool ImageLoaderMachO::isPositionIndependentExecutable() const 
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->filetype == MH_EXECUTE) && ((mh->flags & MH_PIE) != 0) );
+}

 
 

-int
-ImageLoaderMachO::sharedRegionMapFilePrivate(int fd,
-                                                                                        uint64_t offsetInFat,
-                                                                                        uint64_t lenInFat,
-                                                                                        uint64_t fileLen,
-                                                                                        const LinkContext& context,
-                                                                                        bool usemmap)
+
+bool ImageLoaderMachO::forceFlat() const 

 {
 {

-       const unsigned int segmentCount = fSegments.size();
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->flags & MH_FORCE_FLAT) != 0 );
+}

 
 

-       // adjust base address of segments to pack next to last dylib
-       if ( context.slideAndPackDylibs ) {
-               uintptr_t lowestReadOnly = (uintptr_t)(-1);
-               uintptr_t lowestWritable = (uintptr_t)(-1);
-               for(unsigned int segIndex=0; segIndex < segmentCount; ++segIndex){
-                       Segment* seg = fSegments[segIndex];
-                       uintptr_t segEnd = seg->getActualLoadAddress();
-                       if ( seg->writeable() ) {
-                               if ( segEnd < lowestWritable )
-                                       lowestWritable = segEnd;
-                       }
-                       else {
-                               if ( segEnd < lowestReadOnly )
-                                       lowestReadOnly = segEnd;
-                       }
-               }
-               uintptr_t baseAddress;
-               if ( lowestWritable - 256*1024*1024 < lowestReadOnly )
-                       baseAddress = lowestWritable - 256*1024*1024;
-               else
-                       baseAddress = lowestReadOnly;
-               // record that we want dylb slid to fgNextSplitSegAddress
-               this->setSlide(fgNextSplitSegAddress - baseAddress);
-       }
-       
-       // build table of segments to map
-       const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
-       const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
-       _shared_region_mapping_np mappingTable[mappingTableCount];
-       initMappingTable(offsetInFat, mappingTable);
-       uint64_t slide = 0;
-
-       // try map it in privately (don't allow sliding if we pre-calculated the load address to pack dylibs)
-       int r;
-       if ( usemmap )
-               r = _shared_region_map_file_with_mmap(fd, mappingTableCount, mappingTable);
-       else
-               r = _shared_region_map_file_np(fd, mappingTableCount, mappingTable, context.slideAndPackDylibs ? NULL : &slide);
-       if ( 0 == r ) {
-               if ( 0 != slide ) {
-                       slide = (slide) & (-4096); // round down to page boundary
-                       this->setSlide(slide);
-               }
-               if ( context.verboseMapping ) {
-                       if ( slide == 0 )
-                               fprintf(stderr, "dyld: Mapping split-seg un-shared %s\n", this->getPath());
-                       else
-                               fprintf(stderr, "dyld: Mapping split-seg un-shared slid by 0x%08llX %s\n", slide, this->getPath());
-                       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-                               Segment* seg = fSegments[segIndex];
-                               const _shared_region_mapping_np* entry = &mappingTable[entryIndex];
-                               if ( (entry->init_prot & VM_PROT_ZF) == 0 ) 
-                                       fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                       seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
-                               if ( entryIndex < (mappingTableCount-1) ) {
-                                       const _shared_region_mapping_np* nextEntry = &mappingTable[entryIndex+1];
-                                       if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
-                                               uint64_t segOffset = nextEntry->address - entry->address;
-                                               fprintf(stderr, "%18s at 0x%08lX->0x%08lX (zerofill)\n",
-                                                               seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
-                                               ++entryIndex;
-                                       }
-                               }
-                       }
-               }
-               if ( context.slideAndPackDylibs ) {
-                       // calculate where next split-seg dylib can load
-                       uintptr_t largestReadOnly = 0;
-                       uintptr_t largestWritable = 0;
-                       for (unsigned int segIndex=0; segIndex < segmentCount; ++segIndex) {
-                               Segment* seg = fSegments[segIndex];
-                               uintptr_t segEnd = seg->getActualLoadAddress()+seg->getSize();
-                               segEnd = (segEnd+4095) & (-4096); // page align
-                               if ( seg->writeable() ) {
-                                       if ( segEnd > largestWritable )
-                                               largestWritable = segEnd;
-                               }
-                               else {
-                                       if ( segEnd > largestReadOnly )
-                                               largestReadOnly = segEnd;
-                               }
-                       }
-                       if ( largestWritable - 256*1024*1024 > largestReadOnly )
-                               fgNextSplitSegAddress = largestWritable - 256*1024*1024;
-                       else
-                               fgNextSplitSegAddress = largestReadOnly;
-               }
-       }
-       if ( context.slideAndPackDylibs && (r != 0) )
-               throwf("can't rebase split-seg dylib %s because shared_region_map_file_np() returned %d", this->getPath(), r);
-       
-       return r;
+bool ImageLoaderMachO::usesTwoLevelNameSpace() const
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->flags & MH_TWOLEVEL) != 0 );
+}
+
+bool ImageLoaderMachO::isPrebindable() const 
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->flags & MH_PREBOUND) != 0 );

 }
 
 }
 

+bool ImageLoaderMachO::hasCoalescedExports() const 
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->flags & MH_WEAK_DEFINES) != 0 );
+}

 
 

-int
-ImageLoaderMachO::sharedRegionLoadFile(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
+bool ImageLoaderMachO::hasReferencesToWeakSymbols() const 

 {
 {

-       
-       // map in split segment file at random address, then tell kernel to share it
-       void* loadAddress = 0;
-       loadAddress = mmap(NULL, fileLen, PROT_READ, MAP_FILE, fd, 0);
-       if ( loadAddress == ((void*)(-1)) )
-               throw "mmap error";
-
-       // calculate mapping entries
-       const unsigned int segmentCount = fSegments.size();
-       unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
-       
-       // build table of segments to map
-       const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
-       const uintptr_t baseAddress = fSegments[0]->getPreferredLoadAddress();
-       sf_mapping mappingTable[mappingTableCount];
-       initMappingTable(offsetInFat, mappingTable, baseAddress);
-       
-       
-       // use load_shared_file() to map all segments at once
-       int flags = 0; // might need to set NEW_LOCAL_SHARED_REGIONS on first use
-       static bool firstTime = true;
-       if ( firstTime ) {
-               // when NEW_LOCAL_SHARED_REGIONS bit is set, this process will get is own shared region
-               // this is used by Xcode to prevent development libraries from polluting the global shared segment
-               if ( context.sharedRegionMode == kUsePrivateSharedRegion )
-                       flags |= NEW_LOCAL_SHARED_REGIONS;
-               firstTime = false;
-       }
-       
-       caddr_t base_address = (caddr_t)baseAddress;
-       kern_return_t r;
-       r = load_shared_file(   (char*)fPath,           // path of file to map shared
-                                                       (char*)loadAddress, // beginning of local copy of sharable pages in file
-                                                       fileLen,                        // end of shareable pages in file
-                                                       &base_address,          // beginning of address range to map
-                                                       mappingTableCount,  // number of entres in array of sf_mapping
-                                                       mappingTable,           // the array of sf_mapping
-                                                       &flags);                        // in/out flags
-       if ( 0 != r ) {
-               // try again but tell kernel it is ok to slide
-               flags |= ALTERNATE_LOAD_SITE;
-               r = load_shared_file((char*)fPath,(char*)loadAddress, fileLen, &base_address,   
-                                                       mappingTableCount, mappingTable, &flags);
-       }
-       
-       // unmap file from random address now that they are (hopefully) mapped into the shared region
-       munmap(loadAddress, fileLen);
-
-       if ( 0 == r ) {
-               if ( base_address != (caddr_t)baseAddress )
-                       this->setSlide((uintptr_t)base_address - baseAddress);
-               if ( context.verboseMapping ) {
-                       if ( base_address != (caddr_t)baseAddress )
-                               fprintf(stderr, "dyld: Mapping split-seg load_shared_alt_region %s\n", this->getPath());
-                       else
-                               fprintf(stderr, "dyld: Mapping split-seg load_shared %s\n", this->getPath());
-                       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-                               Segment* seg = fSegments[segIndex];
-                               const sf_mapping* entry = &mappingTable[entryIndex];
-                               if ( (entry->protection & VM_PROT_ZF) == 0 )
-                                       fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                       seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
-                               if ( entryIndex < (mappingTableCount-1) ) {
-                                       const sf_mapping* nextEntry = &mappingTable[entryIndex+1];
-                                       if ( (nextEntry->protection & VM_PROT_ZF) != 0 ) {
-                                               fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
-                                                       seg->getName(), (uintptr_t)(nextEntry->mapping_offset + base_address), (uintptr_t)(nextEntry->mapping_offset + base_address + nextEntry->size - 1));
-                                               ++entryIndex;
-                                       }
-                               }
-                       }
-               }
-       }
-       return r;
-}
-void
-ImageLoaderMachO::initMappingTable(uint64_t offsetInFat,
-                                                                  sf_mapping *mappingTable,
-                                                                  uintptr_t baseAddress)
-{
-       unsigned int segmentCount = fSegments.size();
-       for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
-               Segment* seg = fSegments[segIndex];
-               sf_mapping* entry = &mappingTable[entryIndex];
-               entry->mapping_offset   = seg->getPreferredLoadAddress() - baseAddress;
-               entry->size                             = seg->getFileSize();
-               entry->file_offset              = seg->getFileOffset() + offsetInFat;
-               entry->protection               = VM_PROT_NONE;
-               if ( !seg->unaccessible() ) {
-                       if ( seg->executable() )
-                               entry->protection   |= VM_PROT_EXECUTE;
-                       if ( seg->readable() )
-                               entry->protection   |= VM_PROT_READ;
-                       if ( seg->writeable() )
-                               entry->protection   |= VM_PROT_WRITE | VM_PROT_COW;
-               }
-               
-               entry->cksum                    = 0;
-               if ( seg->hasTrailingZeroFill() ) {
-                       sf_mapping* zfentry = &mappingTable[++entryIndex];
-                       zfentry->mapping_offset = entry->mapping_offset + seg->getFileSize();
-                       zfentry->size                   = seg->getSize() - seg->getFileSize();
-                       zfentry->file_offset    = 0;
-                       zfentry->protection             = entry->protection | VM_PROT_COW | VM_PROT_ZF;
-                       zfentry->cksum                  = 0;
-               }
-       }
+       const macho_header* mh = (macho_header*)fMachOData;
+       return ( (mh->flags & MH_BINDS_TO_WEAK) != 0 );
+}
+
+bool ImageLoaderMachO::participatesInCoalescing() const 
+{
+       const macho_header* mh = (macho_header*)fMachOData;
+       // if image is loaded with RTLD_LOCAL, then its symbols' visibility
+       // is reduced and it can't coalesce with other images
+       if ( this->hasHiddenExports() )
+               return false;
+       return ( (mh->flags & (MH_WEAK_DEFINES|MH_BINDS_TO_WEAK)) != 0 );

 }
 
 }
 

-#endif //  !__LP64__  split segs not supported for 64-bits

 
 
 void ImageLoaderMachO::setSlide(intptr_t slide)
 
 
 void ImageLoaderMachO::setSlide(intptr_t slide)


@@ -890,241 +1134,225 @@ void ImageLoaderMachO::setSlide(intptr_t slide)
        fSlide = slide;
 }
 
        fSlide = slide;
 }
 

-void ImageLoaderMachO::parseLoadCmds()
+void ImageLoaderMachO::loadCodeSignature(const struct linkedit_data_command* codeSigCmd, int fd,  uint64_t offsetInFatFile, const LinkContext& context)

 {
 {

-       // now that segments are mapped in, get real fMachOData, fLinkEditBase, and fSlide
-       const unsigned int segmentCount = fSegments.size();
-       for(unsigned int i=0; i < segmentCount; ++i){
-               Segment* seg = fSegments[i];
-               // set up pointer to __LINKEDIT segment
-               if ( strcmp(seg->getName(),"__LINKEDIT") == 0 ) 
-                       fLinkEditBase = (uint8_t*)(seg->getActualLoadAddress() - seg->getFileOffset());
-               // __TEXT segment always starts at beginning of file and contains mach_header and load commands
-               if ( strcmp(seg->getName(),"__TEXT") == 0 ) {
-                       if ( seg->hasFixUps() )
-                               fTextSegmentWithFixups = (SegmentMachO*)seg;
+       dyld3::ScopedTimer(DBG_DYLD_TIMING_ATTACH_CODESIGNATURE, 0, 0, 0);
+       // if dylib being loaded has no code signature load command
+       if ( codeSigCmd == NULL) {
+               disableCoverageCheck();
+       }
+       else {
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+               // <rdar://problem/13622786> ignore code signatures in binaries built with pre-10.9 tools
+               if ( this->sdkVersion() < DYLD_MACOSX_VERSION_10_9 ) {
+                       disableCoverageCheck();
+                       return;

                }
                }

-               // some segment always starts at beginning of file and contains mach_header and load commands
-               if ( (seg->getFileOffset() == 0) && (seg->getFileSize() != 0) ) {
-                       fMachOData = (uint8_t*)(seg->getActualLoadAddress());
+#endif
+
+               fsignatures_t siginfo;
+               siginfo.fs_file_start=offsetInFatFile;                          // start of mach-o slice in fat file
+               siginfo.fs_blob_start=(void*)(long)(codeSigCmd->dataoff);       // start of CD in mach-o file
+               siginfo.fs_blob_size=codeSigCmd->datasize;                      // size of CD
+               int result = fcntl(fd, F_ADDFILESIGS_RETURN, &siginfo);
+
+#if TARGET_IPHONE_SIMULATOR
+               // rdar://problem/18759224> check range covered by the code directory after loading
+               // Attempt to fallback only if we are in the simulator
+
+               if ( result == -1 ) {
+                       result = fcntl(fd, F_ADDFILESIGS, &siginfo);
+                       siginfo.fs_file_start = codeSigCmd->dataoff;
+               }
+#endif
+
+               if ( result == -1 ) {
+                       if ( (errno == EPERM) || (errno == EBADEXEC) )
+                               dyld::throwf("code signature invalid for '%s'\n", this->getPath());
+                       if ( context.verboseCodeSignatures )
+                               dyld::log("dyld: Failed registering code signature for %s, errno=%d\n", this->getPath(), errno);
+                       siginfo.fs_file_start = UINT64_MAX;
+               } else if ( context.verboseCodeSignatures )  {
+                       dyld::log("dyld: Registered code signature for %s\n", this->getPath());

                }
                }

+               fCoveredCodeLength = siginfo.fs_file_start;

        }
 
        }
 

-       // keep count of prebound images with weak exports
-       if ( this->hasCoalescedExports() )
-               ++fgCountOfImagesWithWeakExports;
+       {
+               fchecklv checkInfo;
+               char  messageBuffer[512];
+               messageBuffer[0] = '\0';
+               checkInfo.lv_file_start = offsetInFatFile;
+               checkInfo.lv_error_message_size = sizeof(messageBuffer);
+               checkInfo.lv_error_message = messageBuffer;
+               int res = fcntl(fd, F_CHECK_LV, &checkInfo);
+               if ( res == -1 ) {
+                       dyld::throwf("code signature in (%s) not valid for use in process using Library Validation: %s", this->getPath(), messageBuffer);
+               }
+       }
+}

 
 

-       // walk load commands (mapped in at start of __TEXT segment)
+void ImageLoaderMachO::validateFirstPages(const struct linkedit_data_command* codeSigCmd, int fd, const uint8_t *fileData, size_t lenFileData, off_t offsetInFat, const LinkContext& context)
+{
+#if __MAC_OS_X_VERSION_MIN_REQUIRED
+       // rdar://problem/21839703> 15A226d: dyld crashes in mageLoaderMachO::validateFirstPages during dlopen() after encountering an mmap failure
+       // We need to ignore older code signatures because they will be bad.
+       if ( this->sdkVersion() < DYLD_MACOSX_VERSION_10_9 ) {
+               return;
+       }
+#endif
+       if (codeSigCmd != NULL) {
+               void *fdata = xmmap(NULL, lenFileData, PROT_READ, MAP_SHARED, fd, offsetInFat);
+               if ( fdata == MAP_FAILED ) {
+                       int errnoCopy = errno;
+                       if ( errnoCopy == EPERM ) {
+                               if ( dyld::sandboxBlockedMmap(getPath()) )
+                                       dyld::throwf("file system sandbox blocked mmap() of '%s'", getPath());
+                               else
+                                       dyld::throwf("code signing blocked mmap() of '%s'", getPath());
+                       }
+                       else
+                               dyld::throwf("mmap() errno=%d validating first page of '%s'", errnoCopy, getPath());
+               }
+               if ( memcmp(fdata, fileData, lenFileData) != 0 )
+                       dyld::throwf("mmap() page compare failed for '%s'", getPath());
+               munmap(fdata, lenFileData);
+       }
+}
+
+
+const char* ImageLoaderMachO::getInstallPath() const
+{
+       if ( fDylibIDOffset != 0 ) {
+               const dylib_command* dylibID = (dylib_command*)(&fMachOData[fDylibIDOffset]);
+               return (char*)dylibID + dylibID->dylib.name.offset;
+       }
+       return NULL;
+}
+
+void ImageLoaderMachO::registerInterposing(const LinkContext& context)
+{
+       // mach-o files advertise interposing by having a __DATA __interpose section
+       struct InterposeData { uintptr_t replacement; uintptr_t replacee; };

        const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
                switch (cmd->cmd) {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
                switch (cmd->cmd) {

-                       case LC_SYMTAB:
-                               {
-                                       const struct symtab_command* symtab = (struct symtab_command*)cmd;
-                                       fStrings = (const char*)&fLinkEditBase[symtab->stroff];
-                                       fSymbolTable = (struct macho_nlist*)(&fLinkEditBase[symtab->symoff]);
-                               }
-                               break;
-                       case LC_DYSYMTAB:
-                               fDynamicInfo = (struct dysymtab_command*)cmd;
-                               break;
-                       case LC_SUB_UMBRELLA:
-                               fHasSubUmbrella = true;
-                               break;
-                       case LC_SUB_FRAMEWORK:
-                               {
-                                       const struct sub_framework_command* subf = (struct sub_framework_command*)cmd;
-                                       fReExportThruFramework = (char*)cmd + subf->umbrella.offset;
-                               }
-                               break;
-                       case LC_SUB_LIBRARY:
-                               fHasSubLibraries = true;
-                               break;
-                       case LC_ROUTINES_COMMAND:
-                               fDashInit = (struct macho_routines_command*)cmd;
-                               break;

                        case LC_SEGMENT_COMMAND:
                                {
                                        const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
                        case LC_SEGMENT_COMMAND:
                                {
                                        const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;

-                                       const bool isDataSeg = (strcmp(seg->segname, "__DATA") == 0);

                                        const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
                                        const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
                                        for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                        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_MOD_INIT_FUNC_POINTERS )
-                                                       fModInitSection = sect;
-                                               else if ( type == S_MOD_TERM_FUNC_POINTERS )
-                                                       fModTermSection = sect;
-                                               else if ( isDataSeg && (strcmp(sect->sectname, "__dyld") == 0) ) {
-                                                               fDATAdyld = sect;
+                                               if ( ((sect->flags & SECTION_TYPE) == S_INTERPOSING) || ((strcmp(sect->sectname, "__interpose") == 0) && (strcmp(seg->segname, "__DATA") == 0)) ) {
+                                                       // <rdar://problem/23929217> Ensure section is within segment
+                                                       if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
+                                                               dyld::throwf("interpose section has malformed address range for %s\n", this->getPath());
+                                                       const InterposeData* interposeArray = (InterposeData*)(sect->addr + fSlide);
+                                                       const size_t count = sect->size / sizeof(InterposeData);
+                                                       for (size_t j=0; j < count; ++j) {
+                                                               ImageLoader::InterposeTuple tuple;
+                                                               tuple.replacement               = interposeArray[j].replacement;
+                                                               tuple.neverImage                = this;
+                                                               tuple.onlyImage             = NULL;
+                                                               tuple.replacee                  = interposeArray[j].replacee;
+                                                               // <rdar://problem/25686570> ignore interposing on a weak function that does not exist
+                                                               if ( tuple.replacee == 0 )
+                                                                       continue;
+                                                               // <rdar://problem/7937695> verify that replacement is in this image
+                                                               if ( this->containsAddress((void*)tuple.replacement) ) {
+                                                                       // chain to any existing interpositions
+                                                                       for (std::vector<InterposeTuple>::iterator it=fgInterposingTuples.begin(); it != fgInterposingTuples.end(); it++) {
+                                                                               if ( it->replacee == tuple.replacee ) {
+                                                                                       tuple.replacee = it->replacement;
+                                                                               }
+                                                                       }
+                                                                       ImageLoader::fgInterposingTuples.push_back(tuple);
+                                                               }
+                                                       }

                                                }
                                                }

-                                               else if ( isDataSeg && (strcmp(sect->sectname, "__image_notify") == 0) )
-                                                       fImageNotifySection = sect;

                                        }
                                }
                                break;
                                        }
                                }
                                break;

-                       case LC_TWOLEVEL_HINTS:
-                               fTwoLevelHints = (struct twolevel_hints_command*)cmd;
-                               break;
-                       case LC_ID_DYLIB:
-                               {
-                                       fDylibID = (struct dylib_command*)cmd;
-                               }
-                               break;
-                       case LC_LOAD_WEAK_DYLIB:
-                               // do nothing, just prevent LC_REQ_DYLD exception from occuring
-                               break;
-                       default:
-                               if ( (cmd->cmd & LC_REQ_DYLD) != 0 )
-                                       throwf("unknown required load command 0x%08X", cmd->cmd);

                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
 }
 
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
 }
 

-
-
-
-const char* ImageLoaderMachO::getInstallPath() const
+uint32_t ImageLoaderMachO::sdkVersion(const mach_header* mh)

 {
 {

-       if ( fDylibID != NULL ) {
-               return (char*)fDylibID + fDylibID->dylib.name.offset;
+       const uint32_t cmd_count = mh->ncmds;
+       const struct load_command* const cmds = (struct load_command*)(((char*)mh) + sizeof(macho_header));
+       const struct load_command* cmd = cmds;
+       const struct version_min_command* versCmd;
+       const struct build_version_command* buildVersCmd;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch ( cmd->cmd ) {
+                       case LC_VERSION_MIN_MACOSX:
+                       case LC_VERSION_MIN_IPHONEOS:
+                       case LC_VERSION_MIN_TVOS:
+                       case LC_VERSION_MIN_WATCHOS:
+                               versCmd = (version_min_command*)cmd;
+                               return versCmd->sdk;
+                       case LC_BUILD_VERSION:
+                               buildVersCmd = (build_version_command*)cmd;
+                               return buildVersCmd->sdk;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       return NULL;
+       return 0;

 }
 
 }
 

-// test if this image is re-exported through parent (the image that loaded this one)
-bool ImageLoaderMachO::isSubframeworkOf(const LinkContext& context, const ImageLoader* parent) const
-{
-       if ( fReExportThruFramework != NULL ) {
-               // need to match LC_SUB_FRAMEWORK string against the leaf name of the install location of parent...
-               const char* parentInstallPath = parent->getInstallPath();
-               if ( parentInstallPath != NULL ) {
-                       const char* lastSlash = strrchr(parentInstallPath, '/');
-                       if ( lastSlash != NULL ) {
-                               if ( strcmp(&lastSlash[1], fReExportThruFramework) == 0 )
-                                       return true;
-                               if ( context.imageSuffix != NULL ) {
-                                       // when DYLD_IMAGE_SUFFIX is used, lastSlash string needs imageSuffix removed from end
-                                       char reexportAndSuffix[strlen(context.imageSuffix)+strlen(fReExportThruFramework)+1];
-                                       strcpy(reexportAndSuffix, fReExportThruFramework);
-                                       strcat(reexportAndSuffix, context.imageSuffix);
-                                       if ( strcmp(&lastSlash[1], reexportAndSuffix) == 0 )
-                                               return true;
-                               }
-                       }
-               }
-       }
-       return false;
+uint32_t ImageLoaderMachO::sdkVersion() const
+{
+       return ImageLoaderMachO::sdkVersion(machHeader());

 }
 
 }
 

-// test if child is re-exported 
-bool ImageLoaderMachO::hasSubLibrary(const LinkContext& context, const ImageLoader* child) const
+uint32_t ImageLoaderMachO::minOSVersion(const mach_header* mh)

 {
 {

-       if ( fHasSubLibraries ) {
-               // need to match LC_SUB_LIBRARY string against the leaf name (without extension) of the install location of child...
-               const char* childInstallPath = child->getInstallPath();
-               if ( childInstallPath != NULL ) {
-                       const char* lastSlash = strrchr(childInstallPath, '/');
-                       if ( lastSlash != NULL ) {
-                               const char* firstDot = strchr(lastSlash, '.');
-                               int len;
-                               if ( firstDot == NULL )
-                                       len = strlen(lastSlash);
-                               else
-                                       len = firstDot-lastSlash-1;
-                               char childLeafName[len+1];
-                               strncpy(childLeafName, &lastSlash[1], len);
-                               childLeafName[len] = '\0';
-                               const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
-                                       switch (cmd->cmd) {
-                                               case LC_SUB_LIBRARY:
-                                                       {
-                                                               const struct sub_library_command* lib = (struct sub_library_command*)cmd;
-                                                               const char* aSubLibName = (char*)cmd + lib->sub_library.offset;
-                                                               if ( strcmp(aSubLibName, childLeafName) == 0 )
-                                                                       return true;
-                                                               if ( context.imageSuffix != NULL ) {
-                                                                       // when DYLD_IMAGE_SUFFIX is used, childLeafName string needs imageSuffix removed from end
-                                                                       char aSubLibNameAndSuffix[strlen(context.imageSuffix)+strlen(aSubLibName)+1];
-                                                                       strcpy(aSubLibNameAndSuffix, aSubLibName);
-                                                                       strcat(aSubLibNameAndSuffix, context.imageSuffix);
-                                                                       if ( strcmp(aSubLibNameAndSuffix, childLeafName) == 0 )
-                                                                               return true;
-                                                               }
-                                                       }
-                                                       break;
-                                       }
-                                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
-                               }
-                       }
-               }
-       }
-       if ( fHasSubUmbrella ) {
-               // need to match LC_SUB_UMBRELLA string against the leaf name of install location of child...
-               const char* childInstallPath = child->getInstallPath();
-               if ( childInstallPath != NULL ) {
-                       const char* lastSlash = strrchr(childInstallPath, '/');
-                       if ( lastSlash != NULL ) {
-                               const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
-                                       switch (cmd->cmd) {
-                                               case LC_SUB_UMBRELLA:
-                                                       {
-                                                               const struct sub_umbrella_command* um = (struct sub_umbrella_command*)cmd;
-                                                               const char* aSubUmbrellaName = (char*)cmd + um->sub_umbrella.offset;
-                                                               if ( strcmp(aSubUmbrellaName, &lastSlash[1]) == 0 )
-                                                                       return true;
-                                                               if ( context.imageSuffix != NULL ) {
-                                                                       // when DYLD_IMAGE_SUFFIX is used, lastSlash string needs imageSuffix removed from end
-                                                                       char umbrellaAndSuffix[strlen(context.imageSuffix)+strlen(aSubUmbrellaName)+1];
-                                                                       strcpy(umbrellaAndSuffix, aSubUmbrellaName);
-                                                                       strcat(umbrellaAndSuffix, context.imageSuffix);
-                                                                       if ( strcmp(umbrellaAndSuffix, &lastSlash[1]) == 0 )
-                                                                               return true;
-                                                               }
-                                                       }
-                                                       break;
-                                       }
-                                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
-                               }
-                       }
+       const uint32_t cmd_count = mh->ncmds;
+       const struct load_command* const cmds = (struct load_command*)(((char*)mh) + sizeof(macho_header));
+       const struct load_command* cmd = cmds;
+       const struct version_min_command* versCmd;
+       const struct build_version_command* buildVersCmd;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch ( cmd->cmd ) {
+                       case LC_VERSION_MIN_MACOSX:
+                       case LC_VERSION_MIN_IPHONEOS:
+                       case LC_VERSION_MIN_TVOS:
+                       case LC_VERSION_MIN_WATCHOS:
+                               versCmd = (version_min_command*)cmd;
+                               return versCmd->version;
+                       case LC_BUILD_VERSION:
+                               buildVersCmd = (build_version_command*)cmd;
+                               return buildVersCmd->minos;

                }
                }

+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       return false;
+       return 0;

 }
 
 }
 

-       
-void* ImageLoaderMachO::getMain() const
+uint32_t ImageLoaderMachO::minOSVersion() const
+{
+       return ImageLoaderMachO::minOSVersion(machHeader());
+}
+
+
+void* ImageLoaderMachO::getEntryFromLC_MAIN() const

 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
        const struct load_command* cmd = cmds;
 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
        const struct load_command* cmd = cmds;

-       for (unsigned long i = 0; i < cmd_count; ++i) {
-               switch (cmd->cmd) {
-                       case LC_UNIXTHREAD:
-                       {
-                       #if __ppc__
-                               const ppc_thread_state_t* registers = (ppc_thread_state_t*)(((char*)cmd) + 16);
-                               return (void*)registers->srr0;
-                       #elif __ppc64__
-                               const ppc_thread_state64_t* registers = (ppc_thread_state64_t*)(((char*)cmd) + 16);
-                               return (void*)registers->srr0;
-                       #elif __i386__
-                               const i386_thread_state_t* registers = (i386_thread_state_t*)(((char*)cmd) + 16);
-                               return (void*)registers->eip;
-                       #else
-                               #warning need processor specific code
-                       #endif
-                       }
-                       break;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               if ( cmd->cmd == LC_MAIN ) {
+                       entry_point_command* mainCmd = (entry_point_command*)cmd;
+                       void* entry = (void*)(mainCmd->entryoff + (char*)fMachOData);
+                       // <rdar://problem/8543820&9228031> verify entry point is in image
+                       if ( this->containsAddress(entry) )
+                               return entry;
+                       else
+                               throw "LC_MAIN entryoff is out of range";

                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }


@@ -1132,60 +1360,127 @@ void* ImageLoaderMachO::getMain() const
 }
 
 
 }
 
 

-uint32_t ImageLoaderMachO::doGetDependentLibraryCount()
+void* ImageLoaderMachO::getEntryFromLC_UNIXTHREAD() const

 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];

-       uint32_t count = 0;

        const struct load_command* cmd = cmds;
        const struct load_command* cmd = cmds;

-       for (unsigned long i = 0; i < cmd_count; ++i) {
-               switch (cmd->cmd) {
-                       case LC_LOAD_DYLIB:
-                       case LC_LOAD_WEAK_DYLIB:
-                               ++count;
-                               break;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               if ( cmd->cmd == LC_UNIXTHREAD ) {
+       #if __i386__
+                       const i386_thread_state_t* registers = (i386_thread_state_t*)(((char*)cmd) + 16);
+                       void* entry = (void*)(registers->eip + fSlide);
+                       // <rdar://problem/8543820&9228031> verify entry point is in image
+                       if ( this->containsAddress(entry) )
+                               return entry;
+       #elif __x86_64__
+                       const x86_thread_state64_t* registers = (x86_thread_state64_t*)(((char*)cmd) + 16);
+                       void* entry = (void*)(registers->rip + fSlide);
+                       // <rdar://problem/8543820&9228031> verify entry point is in image
+                       if ( this->containsAddress(entry) )
+                               return entry;
+       #elif __arm64__ && !__arm64e__
+                       // temp support until <rdar://39514191> is fixed
+                       const uint64_t* regs64 = (uint64_t*)(((char*)cmd) + 16);
+                       void* entry = (void*)(regs64[32] + fSlide); // arm_thread_state64_t.__pc
+                       // <rdar://problem/8543820&9228031> verify entry point is in image
+                       if ( this->containsAddress(entry) )
+                               return entry;
+       #endif

                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }

-       return count;
+       throw "no valid entry point";

 }
 
 }
 

-void ImageLoaderMachO::doGetDependentLibraries(DependentLibrary libs[])
+bool ImageLoaderMachO::needsAddedLibSystemDepency(unsigned int libCount, const macho_header* mh)

 {
 {

-       uint32_t index = 0;
-       const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
-       const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
+       // <rdar://problem/6357561> ensure that every image depends on something which depends on libSystem
+       if ( libCount > 1 )
+               return false;
+               
+       // <rdar://problem/6409800> dyld implicit-libSystem breaks valgrind
+       if ( mh->filetype == MH_EXECUTE ) 
+               return false;
+       
+       bool isNonOSdylib = false;
+       const uint32_t cmd_count = mh->ncmds;
+       const struct load_command* const cmds = (struct load_command*)((uint8_t*)mh+sizeof(macho_header));

        const struct load_command* cmd = cmds;
        const struct load_command* cmd = cmds;

-       for (unsigned long i = 0; i < cmd_count; ++i) {
+       for (uint32_t i = 0; i < cmd_count; ++i) {

                switch (cmd->cmd) {
                        case LC_LOAD_DYLIB:
                        case LC_LOAD_WEAK_DYLIB:
                switch (cmd->cmd) {
                        case LC_LOAD_DYLIB:
                        case LC_LOAD_WEAK_DYLIB:

-                       {
-                               const struct dylib_command* dylib = (struct dylib_command*)cmd;
-                               DependentLibrary* lib = &libs[index++];
-                               lib->name = (char*)cmd + dylib->dylib.name.offset;
-                               //lib->name = strdup((char*)cmd + dylib->dylib.name.offset);
-                               lib->image = NULL;
-                               lib->info.checksum = dylib->dylib.timestamp;
-                               lib->info.minVersion = dylib->dylib.compatibility_version;
-                               lib->info.maxVersion = dylib->dylib.current_version;
-                               lib->required = (cmd->cmd == LC_LOAD_DYLIB);
-                               lib->checksumMatches = false;
-                               lib->isReExported = false;
-                       }
-                       break;
+                       case LC_REEXPORT_DYLIB:
+                       case LC_LOAD_UPWARD_DYLIB:
+                               return false;
+                       case LC_ID_DYLIB:
+                               {
+                               const dylib_command* dylibID = (dylib_command*)cmd;
+                               const char* installPath = (char*)cmd + dylibID->dylib.name.offset;
+                               // It is OK for OS dylibs (libSystem or libmath or Rosetta shims) to have no dependents
+                               // but all other dylibs must depend on libSystem for initialization to initialize libSystem first
+                               // <rdar://problem/6497528> rosetta circular dependency spew
+                               isNonOSdylib = ( (strncmp(installPath, "/usr/lib/", 9) != 0) && (strncmp(installPath, "/usr/libexec/oah/Shims", 9) != 0) );
+                               }
+                               break;

                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }

+       return isNonOSdylib;
+}
+
+
+void ImageLoaderMachO::doGetDependentLibraries(DependentLibraryInfo libs[])
+{
+       if ( needsAddedLibSystemDepency(libraryCount(), (macho_header*)fMachOData) ) {
+               DependentLibraryInfo* lib = &libs[0];
+               lib->name = LIBSYSTEM_DYLIB_PATH;
+               lib->info.checksum = 0;
+               lib->info.minVersion = 0;
+               lib->info.maxVersion = 0;
+               lib->required = false;
+               lib->reExported = false;
+               lib->upward = false;
+       }
+       else {
+               uint32_t index = 0;
+               const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+                       switch (cmd->cmd) {
+                               case LC_LOAD_DYLIB:
+                               case LC_LOAD_WEAK_DYLIB:
+                               case LC_REEXPORT_DYLIB:
+                               case LC_LOAD_UPWARD_DYLIB:
+                               {
+                                       const struct dylib_command* dylib = (struct dylib_command*)cmd;
+                                       DependentLibraryInfo* lib = &libs[index++];
+                                       lib->name = (char*)cmd + dylib->dylib.name.offset;
+                                       //lib->name = strdup((char*)cmd + dylib->dylib.name.offset);
+                                       lib->info.checksum = dylib->dylib.timestamp;
+                                       lib->info.minVersion = dylib->dylib.compatibility_version;
+                                       lib->info.maxVersion = dylib->dylib.current_version;
+                                       lib->required = (cmd->cmd != LC_LOAD_WEAK_DYLIB);
+                                       lib->reExported = (cmd->cmd == LC_REEXPORT_DYLIB);
+                                       lib->upward = (cmd->cmd == LC_LOAD_UPWARD_DYLIB);
+                               }
+                               break;
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+               }
+       }

 }
 
 }
 

-ImageLoader::LibraryInfo ImageLoaderMachO::doGetLibraryInfo()
+ImageLoader::LibraryInfo ImageLoaderMachO::doGetLibraryInfo(const LibraryInfo&)

 {
        LibraryInfo info;
 {
        LibraryInfo info;

-       if ( fDylibID != NULL ) {
-               info.minVersion = fDylibID->dylib.compatibility_version;
-               info.maxVersion = fDylibID->dylib.current_version;
-               info.checksum = fDylibID->dylib.timestamp;
+       if ( fDylibIDOffset != 0 ) {
+               const dylib_command* dylibID = (dylib_command*)(&fMachOData[fDylibIDOffset]);
+               info.minVersion = dylibID->dylib.compatibility_version;
+               info.maxVersion = dylibID->dylib.current_version;
+               info.checksum = dylibID->dylib.timestamp;

        }
        else {
                info.minVersion = 0;
        }
        else {
                info.minVersion = 0;


@@ -1195,440 +1490,378 @@ ImageLoader::LibraryInfo ImageLoaderMachO::doGetLibraryInfo()
        return info;
 }
 
        return info;
 }
 

-uintptr_t ImageLoaderMachO::getFirstWritableSegmentAddress()
+void ImageLoaderMachO::getRPaths(const LinkContext& context, std::vector<const char*>& paths) const

 {
 {

-       // in split segment libraries r_address is offset from first writable segment
-       for (std::vector<class Segment*>::iterator it=fSegments.begin(); it != fSegments.end(); ++it) {
-               if ( (*it)->writeable() ) {
-                       return (*it)->getActualLoadAddress();
+       const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+               switch (cmd->cmd) {
+                       case LC_RPATH:
+                               const char* pathToAdd = NULL;
+                               const char* path = (char*)cmd + ((struct rpath_command*)cmd)->path.offset;
+                               if ( (strncmp(path, "@loader_path", 12) == 0) && ((path[12] == '/') || (path[12] == '\0')) ) {
+                                       if ( !context.allowAtPaths && (context.mainExecutable == this) ) {
+                                               dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @loader_path\n", path, this->getPath());
+                                               break;
+                                       }
+                                       char resolvedPath[PATH_MAX];
+                                       if ( realpath(this->getPath(), resolvedPath) != NULL ) {
+                                               char newRealPath[strlen(resolvedPath) + strlen(path)];
+                                               strcpy(newRealPath, resolvedPath);
+                                               char* addPoint = strrchr(newRealPath,'/');
+                                               if ( addPoint != NULL ) {
+                                                       strcpy(addPoint, &path[12]);
+                                                       pathToAdd = strdup(newRealPath);
+                                               }
+                                       }
+                               }
+                               else if ( (strncmp(path, "@executable_path", 16) == 0) && ((path[16] == '/') || (path[16] == '\0')) ) {
+                                       if ( !context.allowAtPaths) {
+                                               dyld::warn("LC_RPATH %s in %s being ignored in restricted program because of @executable_path\n", path, this->getPath());
+                                               break;
+                                       }
+                                       char resolvedPath[PATH_MAX];
+                                       if ( realpath(context.mainExecutable->getPath(), resolvedPath) != NULL ) {
+                                               char newRealPath[strlen(resolvedPath) + strlen(path)];
+                                               strcpy(newRealPath, resolvedPath);
+                                               char* addPoint = strrchr(newRealPath,'/');
+                                               if ( addPoint != NULL ) {
+                                                       strcpy(addPoint, &path[16]);
+                                                       pathToAdd = strdup(newRealPath);
+                                               }
+                                       }
+                               }
+                               else if ( (path[0] != '/') && !context.allowAtPaths) {
+                                       dyld::warn("LC_RPATH %s in %s being ignored in restricted program because it is a relative path\n", path, this->getPath());
+                                       break;
+                               }
+#if SUPPORT_ROOT_PATH
+                               else if ( (path[0] == '/') && (context.rootPaths != NULL) ) {
+                                       // <rdar://problem/5869973> DYLD_ROOT_PATH should apply to LC_RPATH rpaths
+                                       // DYLD_ROOT_PATH can be a list of paths, but at this point we can only support one, so use first combination that exists
+                                       bool found = false;
+                                       for(const char** rp = context.rootPaths; *rp != NULL; ++rp) {
+                                               char newPath[PATH_MAX];
+                                               strlcpy(newPath, *rp, PATH_MAX);
+                                               strlcat(newPath, path, PATH_MAX);
+                                               struct stat stat_buf;
+                                               if ( stat(newPath, &stat_buf) != -1 ) {
+                                                       //dyld::log("combined DYLD_ROOT_PATH and LC_RPATH: %s\n", newPath);
+                                                       pathToAdd = strdup(newPath);
+                                                       found = true;
+                                                       break;
+                                               }
+                                       }
+                                       if ( ! found ) {
+                                               // make copy so that all elements of 'paths' can be freed
+                                               pathToAdd = strdup(path);
+                                       }
+                               }
+#endif
+                               else {
+                                       // make copy so that all elements of 'paths' can be freed
+                                       pathToAdd = strdup(path);
+                               }
+                               if ( pathToAdd != NULL )
+                                       paths.push_back(pathToAdd);
+                               break;

                }
                }

+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       throw "no writable segment";

 }
 
 }
 

-uintptr_t ImageLoaderMachO::getRelocBase()
-{
-#if __ppc__ || __i386__
-       if ( fIsSplitSeg ) {
-               // in split segment libraries r_address is offset from first writable segment
-               return getFirstWritableSegmentAddress();
-       }
-#endif
-       
-       // in non-split segment libraries r_address is offset from first segment
-       return fSegments[0]->getActualLoadAddress();
-}

 
 

-#if __ppc__
-static inline void otherRelocsPPC(uintptr_t* locationToFix, uint8_t relocationType, uint16_t otherHalf, uintptr_t slide)
+bool ImageLoaderMachO::getUUID(uuid_t uuid) const

 {
 {

-       // low 16 bits of 32-bit ppc instructions need fixing
-       struct ppcInstruction { uint16_t opcode; int16_t immediateValue; };
-       ppcInstruction* instruction = (ppcInstruction*)locationToFix;
-       //uint32_t before = *((uint32_t*)locationToFix);
-       switch ( relocationType )
-       {
-               case PPC_RELOC_LO16: 
-                       instruction->immediateValue = ((otherHalf << 16) | instruction->immediateValue) + slide;
-                       break;
-               case PPC_RELOC_HI16: 
-                       instruction->immediateValue = ((((instruction->immediateValue << 16) | otherHalf) + slide) >> 16);
-                       break;
-               case PPC_RELOC_HA16: 
-                       int16_t signedOtherHalf = (int16_t)(otherHalf & 0xffff);
-                       uint32_t temp = (instruction->immediateValue << 16) + signedOtherHalf + slide;
-                       if ( (temp & 0x00008000) != 0 )
-                               temp += 0x00008000;
-                       instruction->immediateValue = temp >> 16;
+       const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+               switch (cmd->cmd) {
+                       case LC_UUID:
+                               uuid_command* uc = (uuid_command*)cmd;
+                               memcpy(uuid, uc->uuid, 16);
+                               return true;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       //uint32_t after = *((uint32_t*)locationToFix);
-       //fprintf(stderr, "dyld: ppc fixup %0p type %d from 0x%08X to 0x%08X\n", locationToFix, relocationType, before, after);
+       bzero(uuid, 16);
+       return false;

 }
 }

-#endif

 
 void ImageLoaderMachO::doRebase(const LinkContext& context)
 {
 
 void ImageLoaderMachO::doRebase(const LinkContext& context)
 {

+       // <rdar://problem/25329861> Delay calling setNeverUnload() until we know this is not for dlopen_preflight()
+       if ( fRetainForObjC )
+               this->setNeverUnload();
+
+    // dylibs with thread local variables cannot be unloaded because there is no way to clean up all threads
+    if ( !this->inSharedCache() && (this->machHeader()->flags & MH_HAS_TLV_DESCRIPTORS) )
+        this->setNeverUnload();
+

        // if prebound and loaded at prebound address, then no need to rebase
        // if prebound and loaded at prebound address, then no need to rebase

-       // Note: you might think that the check for allDependentLibrariesAsWhenPreBound() is not needed
-       // but it is.  If a dependent library changed, this image's lazy pointers into that library
-       // need to be updated (reset back to lazy binding handler).  That work is done most easily
-       // here because there is a PPC_RELOC_PB_LA_PTR reloc record for each lazy pointer.
-       if ( this->usablePrebinding(context) && this->usesTwoLevelNameSpace() ) {
-               // skip rebasing cause prebound and prebinding not disabled
+       if ( this->usablePrebinding(context) ) {
+               // skip rebasing because prebinding is valid

                ++fgImagesWithUsedPrebinding; // bump totals for statistics
                return;
        }
                ++fgImagesWithUsedPrebinding; // bump totals for statistics
                return;
        }

-               
+

        // print why prebinding was not used
        if ( context.verbosePrebinding ) {
                if ( !this->isPrebindable() ) {
        // print why prebinding was not used
        if ( context.verbosePrebinding ) {
                if ( !this->isPrebindable() ) {

-                       fprintf(stderr, "dyld: image not prebound, so could not use prebinding in %s\n", this->getPath());
+                       dyld::log("dyld: image not prebound, so could not use prebinding in %s\n", this->getPath());

                }
                else if ( fSlide != 0 ) {
                }
                else if ( fSlide != 0 ) {

-                       fprintf(stderr, "dyld: image slid, so could not use prebinding in %s\n", this->getPath());
+                       dyld::log("dyld: image slid, so could not use prebinding in %s\n", this->getPath());

                }
                else if ( !this->allDependentLibrariesAsWhenPreBound() ) {
                }
                else if ( !this->allDependentLibrariesAsWhenPreBound() ) {

-                       fprintf(stderr, "dyld: dependent libraries changed, so could not use prebinding in %s\n", this->getPath());
+                       dyld::log("dyld: dependent libraries changed, so could not use prebinding in %s\n", this->getPath());

                }
                else if ( !this->usesTwoLevelNameSpace() ){
                }
                else if ( !this->usesTwoLevelNameSpace() ){

-                       fprintf(stderr, "dyld: image uses flat-namespace so, parts of prebinding ignored %s\n", this->getPath());
+                       dyld::log("dyld: image uses flat-namespace so, parts of prebinding ignored %s\n", this->getPath());

                }
                else {
                }
                else {

-                       fprintf(stderr, "dyld: environment variable disabled use of prebinding in %s\n", this->getPath());
+                       dyld::log("dyld: environment variable disabled use of prebinding in %s\n", this->getPath());

                }
        }
 
                }
        }
 

-       // if there are __TEXT fixups, temporarily make __TEXT writable
-       if ( fTextSegmentWithFixups != NULL ) 
-               fTextSegmentWithFixups->tempWritable();
-
-       // cache this value that is used in the following loop
-       register const uintptr_t slide = this->fSlide;
-
-       // loop through all local (internal) relocation records
-       const uintptr_t relocBase = this->getRelocBase();
-       const relocation_info* const relocsStart = (struct relocation_info*)(&fLinkEditBase[fDynamicInfo->locreloff]);
-       const relocation_info* const relocsEnd = &relocsStart[fDynamicInfo->nlocrel];
-       for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
-       #if __ppc__ || __ppc64__ || __i386__
-               if ( (reloc->r_address & R_SCATTERED) == 0 ) {
-                       if ( reloc->r_symbolnum == R_ABS ) {
-                               // ignore absolute relocations
-                       }
-                       else if (reloc->r_length == RELOC_SIZE) {
-                               switch(reloc->r_type) {
-                                       case GENERIC_RELOC_VANILLA:
-                                               *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
-                                               break;
-               #if __ppc__
-                                       case PPC_RELOC_HI16: 
-                                       case PPC_RELOC_LO16: 
-                                       case PPC_RELOC_HA16: 
-                                               // some tools leave object file relocations in linked images
-                                               otherRelocsPPC((uintptr_t*)(reloc->r_address + relocBase), reloc->r_type, reloc[1].r_address, slide);
-                                               ++reloc; // these relocations come in pairs, skip next
-                                               break;
-               #endif
-                                       default:
-                                               throw "unknown local relocation type";
-                               }
-                       }
-                       else {
-                               throw "bad local relocation length";
-                       }
-               }
-               else {
-                       const struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
-                       if (sreloc->r_length == RELOC_SIZE) {
-                               uintptr_t* locationToFix = (uintptr_t*)(sreloc->r_address + relocBase);
-                               switch(sreloc->r_type) {
-                                       case GENERIC_RELOC_VANILLA:
-                                               *locationToFix += slide;
-                                               break;
-               #if __ppc__ || __ppc64__
-                                       case PPC_RELOC_PB_LA_PTR:
-                                               // should only see these in prebound images, and we got here so prebinding is being ignored
-                                               *locationToFix = sreloc->r_value + slide;
-                                               break;
-               #endif
-               #if __ppc__
-                                       case PPC_RELOC_HI16: 
-                                       case PPC_RELOC_LO16: 
-                                       case PPC_RELOC_HA16: 
-                                               // Metrowerks compiler sometimes leaves object file relocations in linked images???
-                                               ++reloc; // these relocations come in pairs, get next one
-                                               otherRelocsPPC(locationToFix, sreloc->r_type, reloc->r_address, slide);
-                                               break;
-               #endif
-               #if __i386__
-                                       case GENERIC_RELOC_PB_LA_PTR:
-                                               // should only see these in prebound images, and we got here so prebinding is being ignored
-                                               *locationToFix = sreloc->r_value + slide;
-                                               break;
-               #endif
-                                       default:
-                                               throw "unknown local scattered relocation type";
-                               }
-                       }
-                       else {
-                               throw "bad local scattered relocation length";
-                       }
-               }
-       #endif 
-       }
-       
-       // if there were __TEXT fixups, restore write protection
-       if ( fTextSegmentWithFixups != NULL ) {
-               fTextSegmentWithFixups->setPermissions();
-               sys_icache_invalidate((void*)fTextSegmentWithFixups->getActualLoadAddress(), fTextSegmentWithFixups->getSize());
-       }
-       
-       // update stats
-       fgTotalRebaseFixups += fDynamicInfo->nlocrel;
-}
+       //dyld::log("slide=0x%08lX for %s\n", slide, this->getPath());

 
 

+#if PREBOUND_IMAGE_SUPPORT
+       // if prebound and we got here, then prebinding is not valid, so reset all lazy pointers
+       // if this image is in the shared cache, do not reset, they will be bound in doBind()
+       if ( this->isPrebindable() && !fInSharedCache )
+               this->resetPreboundLazyPointers(context);
+#endif

 
 

-const struct macho_nlist* ImageLoaderMachO::binarySearchWithToc(const char* key, const char stringPool[], const struct macho_nlist symbols[], 
-                                                                                               const struct dylib_table_of_contents toc[], uint32_t symbolCount, uint32_t hintIndex)
-{
-       int32_t high = symbolCount-1;
-       int32_t mid = hintIndex;
-       
-       // handle out of range hint
-       if ( mid >= (int32_t)symbolCount ) {
-               mid = symbolCount/2;
-               ++ImageLoaderMachO::fgUnhintedBinaryTreeSearchs;
-       }
-       else {
-               ++ImageLoaderMachO::fgHintedBinaryTreeSearchs;
-       }
+       // if loaded at preferred address, no rebasing necessary
+       if ( this->fSlide == 0 ) 
+               return;

 
 

-       for (int32_t low = 0; low <= high; mid = (low+high)/2) {
-               const uint32_t index = toc[mid].symbol_index;
-               const struct macho_nlist* pivot = &symbols[index];
-               const char* pivotStr = &stringPool[pivot->n_un.n_strx];
-#if LINKEDIT_USAGE_DEBUG
-               noteAccessedLinkEditAddress(&toc[mid]);
-               noteAccessedLinkEditAddress(pivot);
-               noteAccessedLinkEditAddress(pivotStr);
+#if TEXT_RELOC_SUPPORT
+       // if there are __TEXT fixups, temporarily make __TEXT writable
+       if ( fTextSegmentRebases ) 
+               this->makeTextSegmentWritable(context, true);

 #endif
 #endif

-               int cmp = astrcmp(key, pivotStr);
-               if ( cmp == 0 )
-                       return pivot;
-               if ( cmp > 0 ) {
-                       // key > pivot 
-                       low = mid + 1;
-               }
-               else {
-                       // key < pivot 
-                       high = mid - 1;
-               }
-       }
-       return NULL;
+
+       // do actual rebasing
+       this->rebase(context, fSlide);
+                       
+#if TEXT_RELOC_SUPPORT
+       // if there were __TEXT fixups, restore write protection
+       if ( fTextSegmentRebases ) 
+               this->makeTextSegmentWritable(context, false);
+       
+#endif 

 }
 
 }
 

-const struct macho_nlist* ImageLoaderMachO::binarySearch(const char* key, const char stringPool[], const struct macho_nlist symbols[], uint32_t symbolCount)
+#if TEXT_RELOC_SUPPORT
+void ImageLoaderMachO::makeTextSegmentWritable(const LinkContext& context, bool writeable)

 {
 {

-       ++ImageLoaderMachO::fgUnhintedBinaryTreeSearchs;
-       const struct macho_nlist* base = symbols;
-       for (uint32_t n = symbolCount; n > 0; n /= 2) {
-               const struct macho_nlist* pivot = &base[n/2];
-               const char* pivotStr = &stringPool[pivot->n_un.n_strx];
-#if LINKEDIT_USAGE_DEBUG
-               noteAccessedLinkEditAddress(pivot);
-               noteAccessedLinkEditAddress(pivotStr);
-#endif
-               int cmp = astrcmp(key, pivotStr);
-               if ( cmp == 0 )
-                       return pivot;
-               if ( cmp > 0 ) {
-                       // key > pivot 
-                       // move base to symbol after pivot
-                       base = &pivot[1];
-                       --n; 
-               }
-               else {
-                       // key < pivot 
-                       // keep same base
+       for(unsigned int i=0; i < fSegmentsCount; ++i) {
+               if ( segExecutable(i) ) {
+                       if ( writeable ) {
+                               segMakeWritable(i, context);
+                       }
+                       else {
+                       #if !__i386__ && !__x86_64__
+                               // some processors require range to be invalidated before it is made executable
+                               sys_icache_invalidate((void*)segActualLoadAddress(i), segSize(textSegmentIndex));
+                       #endif
+                               segProtect(i, context);
+                       }

                }
        }
                }
        }

-       return NULL;
+

 }
 }

+#endif

 
 

-const ImageLoader::Symbol* ImageLoaderMachO::findExportedSymbol(const char* name, const void* hint, bool searchReExports, ImageLoader** foundIn) const
+const ImageLoader::Symbol* ImageLoaderMachO::findExportedSymbol(const char* name, bool searchReExports, const char* thisPath, const ImageLoader** foundIn) const

 {
 {

-       const struct macho_nlist* sym = NULL;
-       const struct twolevel_hint* theHint = (struct twolevel_hint*)hint;
-       if ( fDynamicInfo->tocoff == 0 )
-               sym = binarySearch(name, fStrings, &fSymbolTable[fDynamicInfo->iextdefsym], fDynamicInfo->nextdefsym);
-       else {
-               uint32_t start = fDynamicInfo->nextdefsym;
-               if ( theHint != NULL )
-                        start = theHint->itoc;
-               if ( (theHint == NULL) || (theHint->isub_image == 0) ) {
-                       sym = binarySearchWithToc(name, fStrings, fSymbolTable, (dylib_table_of_contents*)&fLinkEditBase[fDynamicInfo->tocoff], 
-                                                                               fDynamicInfo->ntoc, start);
-               }
-       }
-       if ( sym != NULL ) {
-               if ( foundIn != NULL )
-                       *foundIn = (ImageLoader*)this;          
-                       
-               return (const Symbol*)sym;
-       }
+       // look in this image first
+       const ImageLoader::Symbol* result = this->findShallowExportedSymbol(name, foundIn);
+       if ( result != NULL )
+               return result;

        
        if ( searchReExports ) {
        
        if ( searchReExports ) {

-               // hint might tell us to try a particular subimage
-               if ( (theHint != NULL) && (theHint->isub_image > 0) && (theHint->isub_image <= fLibrariesCount) ) {
-                       // isub_image is an index into a list that is sorted non-rexported images first
-                       uint32_t index = 0;
-                       ImageLoader* target = NULL;
-                       // pass one, only look at sub-frameworks
-                       for (uint32_t i=0; i < fLibrariesCount; ++i) {
-                               DependentLibrary& libInfo =  fLibraries[i];
-                               if ( libInfo.isSubFramework && (libInfo.image != NULL)) {
-                                       if ( ++index == theHint->isub_image ) {
-                                               target = libInfo.image;
-                                               break;
-                                       }
-                               }
-                       }
-                       if (target != NULL) {
-                               // pass two, only look at non-sub-framework-reexports
-                               for (uint32_t i=0; i < fLibrariesCount; ++i) {
-                                       DependentLibrary& libInfo =  fLibraries[i];
-                                       if ( libInfo.isReExported && !libInfo.isSubFramework && (libInfo.image != NULL) ) {
-                                               if ( ++index == theHint->isub_image ) {
-                                                       target = libInfo.image;
-                                                       break;
-                                               }
-                                       }
+               for(unsigned int i=0; i < libraryCount(); ++i){
+                       if ( libReExported(i) ) {
+                               ImageLoader* image = libImage(i);
+                               if ( image != NULL ) {
+                                       const char* reExPath = libPath(i);
+                                       result = image->findExportedSymbol(name, searchReExports, reExPath, foundIn);
+                                       if ( result != NULL )
+                                               return result;

                                }
                        }
                                }
                        }

-                       if (target != NULL) {
-                               const Symbol* result = target->findExportedSymbol(name, NULL, searchReExports, foundIn);
-                               if ( result != NULL )
-                                       return result;
-                       }
-               }
-               
-               // hint failed, try all sub images
-               // pass one, only look at sub-frameworks
-               for(unsigned int i=0; i < fLibrariesCount; ++i){
-                       DependentLibrary& libInfo =  fLibraries[i];
-                       if ( (libInfo.image != NULL) && libInfo.isSubFramework ) {
-                               const Symbol* result = libInfo.image->findExportedSymbol(name, NULL, searchReExports, foundIn);
-                               if ( result != NULL )
-                                       return result;
-                       }
-               }
-               // pass two, only look at non-sub-framework-reexports
-               for(unsigned int i=0; i < fLibrariesCount; ++i){
-                       DependentLibrary& libInfo =  fLibraries[i];
-                       if ( (libInfo.image != NULL) && libInfo.isReExported && !libInfo.isSubFramework ) {
-                               const Symbol* result = libInfo.image->findExportedSymbol(name, NULL, searchReExports, foundIn);
-                               if ( result != NULL )
-                                       return result;
-                       }

                }
        }
        
                }
        }
        

-       // last change: the hint is wrong (non-zero but actually in this image)
-       if ( (theHint != NULL) && (theHint->isub_image != 0) ) {
-               sym = binarySearchWithToc(name, fStrings, fSymbolTable, (dylib_table_of_contents*)&fLinkEditBase[fDynamicInfo->tocoff], 
-                                                                               fDynamicInfo->ntoc, fDynamicInfo->nextdefsym);
-               if ( sym != NULL ) {
-                       if ( foundIn != NULL ) 
-                               *foundIn = (ImageLoader*)this;
-                       return (const Symbol*)sym;
-               }
-       }

 
 

-    

        return NULL;
 }
 
 
        return NULL;
 }
 
 

-uintptr_t ImageLoaderMachO::getExportedSymbolAddress(const Symbol* sym) const
+
+uintptr_t ImageLoaderMachO::getExportedSymbolAddress(const Symbol* sym, const LinkContext& context, 
+                                                                                       const ImageLoader* requestor, bool runResolver, const char* symbolName) const

 {
 {

-       const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
-       return nlistSym->n_value + fSlide;
+       return this->getSymbolAddress(sym, requestor, context, runResolver);
+}
+
+uintptr_t ImageLoaderMachO::getSymbolAddress(const Symbol* sym, const ImageLoader* requestor, 
+                                                                                               const LinkContext& context, bool runResolver) const
+{
+       uintptr_t result = exportedSymbolAddress(context, sym, requestor, runResolver);
+       // check for interposing overrides
+       result = interposedAddress(context, result, requestor);
+       return result;

 }
 
 ImageLoader::DefinitionFlags ImageLoaderMachO::getExportedSymbolInfo(const Symbol* sym) const
 {
 }
 
 ImageLoader::DefinitionFlags ImageLoaderMachO::getExportedSymbolInfo(const Symbol* sym) const
 {

-       const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
-       if ( (nlistSym->n_desc & N_WEAK_DEF) != 0 )
+       if ( exportedSymbolIsWeakDefintion(sym) )

                return kWeakDefinition;
                return kWeakDefinition;

-       return kNoDefinitionOptions;
+       else
+               return kNoDefinitionOptions;

 }
 
 const char* ImageLoaderMachO::getExportedSymbolName(const Symbol* sym) const
 {
 }
 
 const char* ImageLoaderMachO::getExportedSymbolName(const Symbol* sym) const
 {

-       const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
-       return &fStrings[nlistSym->n_un.n_strx];
+       return exportedSymbolName(sym);

 }
 
 uint32_t ImageLoaderMachO::getExportedSymbolCount() const
 {
 }
 
 uint32_t ImageLoaderMachO::getExportedSymbolCount() const
 {

-       return fDynamicInfo->nextdefsym;
+       return exportedSymbolCount();

 }
 
 
 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedExportedSymbol(uint32_t index) const
 {
 }
 
 
 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedExportedSymbol(uint32_t index) const
 {

-       if ( index < fDynamicInfo->nextdefsym ) {
-               const struct macho_nlist* sym = &fSymbolTable[fDynamicInfo->iextdefsym + index];
-               return (const ImageLoader::Symbol*)sym;
-       }
-       return NULL;
+       return exportedSymbolIndexed(index);

 }
 
 
 uint32_t ImageLoaderMachO::getImportedSymbolCount() const
 {
 }
 
 
 uint32_t ImageLoaderMachO::getImportedSymbolCount() const
 {

-       return fDynamicInfo->nundefsym;
+       return importedSymbolCount();

 }
 
 
 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedImportedSymbol(uint32_t index) const
 {
 }
 
 
 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedImportedSymbol(uint32_t index) const
 {

-       if ( index < fDynamicInfo->nundefsym ) {
-               const struct macho_nlist* sym = &fSymbolTable[fDynamicInfo->iundefsym + index];
-               return (const ImageLoader::Symbol*)sym;
+       return importedSymbolIndexed(index);
+}
+
+
+ImageLoader::ReferenceFlags ImageLoaderMachO::getImportedSymbolInfo(const ImageLoader::Symbol* sym) const
+{
+       ImageLoader::ReferenceFlags flags = kNoReferenceOptions;
+       return flags;
+}
+
+
+const char* ImageLoaderMachO::getImportedSymbolName(const ImageLoader::Symbol* sym) const
+{
+       return importedSymbolName(sym);
+}
+
+
+bool ImageLoaderMachO::getSectionContent(const char* segmentName, const char* sectionName, void** start, size_t* length)
+{
+       const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+               switch (cmd->cmd) {
+                       case 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) {
+                                               if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {
+                                                       *start = (uintptr_t*)(sect->addr + fSlide);
+                                                       *length = sect->size;
+                                                       return true;
+                                               }
+                                       }
+                               }
+                               break;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       return NULL;
+       *start = NULL;
+       *length = 0;
+       return false;

 }
 
 }
 

-
-ImageLoader::ReferenceFlags ImageLoaderMachO::geImportedSymbolInfo(const ImageLoader::Symbol* sym) const
+void ImageLoaderMachO::getUnwindInfo(dyld_unwind_sections* info)

 {
 {

-       const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
-       ImageLoader::ReferenceFlags flags = kNoReferenceOptions;
-       if ( ((nlistSym->n_type & N_TYPE) == N_UNDF) && (nlistSym->n_value != 0) )
-               flags |= ImageLoader::kTentativeDefinition;
-       if ( (nlistSym->n_desc & N_WEAK_REF) != 0 )
-               flags |= ImageLoader::kWeakReference;
-       return flags;
+       info->mh = this->machHeader();
+       info->dwarf_section = 0;
+       info->dwarf_section_length = 0;
+       info->compact_unwind_section = 0;
+       info->compact_unwind_section_length = 0;
+       if ( fEHFrameSectionOffset != 0 ) {
+               const macho_section* sect = (macho_section*)&fMachOData[fEHFrameSectionOffset];
+               info->dwarf_section = (void*)(sect->addr + fSlide);
+               info->dwarf_section_length = sect->size;
+       }
+       if ( fUnwindInfoSectionOffset != 0 ) {
+               const macho_section* sect = (macho_section*)&fMachOData[fUnwindInfoSectionOffset];
+               info->compact_unwind_section = (void*)(sect->addr + fSlide);
+               info->compact_unwind_section_length = sect->size;
+       }

 }
 
 }
 

-
-const char* ImageLoaderMachO::getImportedSymbolName(const ImageLoader::Symbol* sym) const
+intptr_t ImageLoaderMachO::computeSlide(const mach_header* mh)

 {
 {

-       const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
-       return &fStrings[nlistSym->n_un.n_strx];
+       const uint32_t cmd_count = mh->ncmds;
+       const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
+       const load_command* cmd = cmds;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
+                       const macho_segment_command* seg = (macho_segment_command*)cmd;
+                       if ( strcmp(seg->segname, "__TEXT") == 0 )
+                               return (char*)mh - (char*)(seg->vmaddr);
+               }
+               cmd = (const load_command*)(((char*)cmd)+cmd->cmdsize);
+       }
+       return 0;

 }
 
 }
 

-
-bool ImageLoaderMachO::getSectionContent(const char* segmentName, const char* sectionName, void** start, size_t* length)
+bool ImageLoaderMachO::findSection(const mach_header* mh, const char* segmentName, const char* sectionName, void** sectAddress, size_t* sectSize)

 {
 {

-       const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
-       const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
-       const struct load_command* cmd = cmds;
+       const uint32_t cmd_count = mh->ncmds;
+       const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
+       const load_command* cmd = cmds;

        for (uint32_t i = 0; i < cmd_count; ++i) {
                switch (cmd->cmd) {
                        case LC_SEGMENT_COMMAND:
                                {
        for (uint32_t i = 0; i < cmd_count; ++i) {
                switch (cmd->cmd) {
                        case LC_SEGMENT_COMMAND:
                                {

-                                       const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
-                                       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 macho_segment_command* seg = (macho_segment_command*)cmd;
+                                       const macho_section* const sectionsStart = (macho_section*)((char*)seg + sizeof(macho_segment_command));
+                                       const macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
+                                       for (const macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {

                                                if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {
                                                if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {

-                                                       *start = (uintptr_t*)(sect->addr + fSlide);
-                                                       *length = sect->size;
+                                                       *sectAddress = (void*)(sect->addr + computeSlide(mh));
+                                                       *sectSize = sect->size;

                                                        return true;
                                                }
                                        }
                                }
                                break;
                }
                                                        return true;
                                                }
                                        }
                                }
                                break;
                }

-               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+               cmd = (const load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        return false;
 }
 
 
        }
        return false;
 }
 
 

-bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segmentName, const char** sectionName, size_t* sectionOffset)
+const macho_section* ImageLoaderMachO::findSection(const void* imageInterior) const

 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
 {
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];


@@ -1644,13 +1877,7 @@ bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segme
                                                const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
                                                for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                                        if ((sect->addr <= unslidInteriorAddress) && (unslidInteriorAddress < (sect->addr+sect->size))) {
                                                const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
                                                for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                                        if ((sect->addr <= unslidInteriorAddress) && (unslidInteriorAddress < (sect->addr+sect->size))) {

-                                                               if ( segmentName != NULL )
-                                                                       *segmentName = sect->segname;
-                                                               if ( sectionName != NULL )
-                                                                       *sectionName = sect->sectname;
-                                                               if ( sectionOffset != NULL )
-                                                                       *sectionOffset = unslidInteriorAddress - sect->addr;
-                                                               return true;
+                                                               return sect;

                                                        }
                                                }
                                        }
                                                        }
                                                }
                                        }


@@ -1659,282 +1886,64 @@ bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segme
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }

-       return false;
+       return nullptr;

 }
 
 
 }
 
 

-bool ImageLoaderMachO::symbolRequiresCoalescing(const struct macho_nlist* symbol)
+bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segmentName, const char** sectionName, size_t* sectionOffset)

 {
 {

-       // if a define and weak ==> coalesced 
-       if ( ((symbol->n_type & N_TYPE) == N_SECT) && ((symbol->n_desc & N_WEAK_DEF) != 0) ) 
-               return true;
-       // if an undefine and not referencing a weak symbol ==> coalesced
-       if ( ((symbol->n_type & N_TYPE) != N_SECT) && ((symbol->n_desc & N_REF_TO_WEAK) != 0) )
+       if (const struct macho_section* sect = findSection(imageInterior)) {
+               const uintptr_t unslidInteriorAddress = (uintptr_t)imageInterior - this->getSlide();
+               if ( segmentName != NULL )
+                       *segmentName = sect->segname;
+               if ( sectionName != NULL )
+                       *sectionName = sect->sectname;
+               if ( sectionOffset != NULL )
+                       *sectionOffset = unslidInteriorAddress - sect->addr;

                return true;
                return true;

-       
-       // regular symbol
-       return false;
-}
-
-
-static void __attribute__((noreturn)) throwSymbolNotFound(const char* symbol, const char* referencedFrom, const char* expectedIn)
-{
-       const char* formatString = "Symbol not found: %s\n  Referenced from: %s\n  Expected in: %s\n";
-       char buf[strlen(symbol)+strlen(referencedFrom)+strlen(expectedIn)+strlen(formatString)];
-       sprintf(buf, formatString, symbol, referencedFrom, expectedIn);
-       throw strdup(buf);  // this is a leak if exception doesn't halt program
-}
-
-uintptr_t ImageLoaderMachO::resolveUndefined(const LinkContext& context, const struct macho_nlist* undefinedSymbol, bool twoLevel, ImageLoader** foundIn)
-{
-       const char* symbolName = &fStrings[undefinedSymbol->n_un.n_strx];
-
-       if ( context.bindFlat || !twoLevel ) {
-               // flat lookup
-               const Symbol* sym;
-               if ( context.flatExportFinder(symbolName, &sym, foundIn) )
-                       return (*foundIn)->getExportedSymbolAddress(sym);
-               // 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->findExportedSymbol(symbolName, NULL, false, foundIn);
-                       if ( sym != NULL )
-                               return (*foundIn)->getExportedSymbolAddress(sym);
-               }
-               if ( ((undefinedSymbol->n_type & N_PEXT) != 0) || ((undefinedSymbol->n_type & N_TYPE) == N_SECT) ) {
-                       // could be a multi-module private_extern internal reference
-                       // the static linker squirrels away the target address in n_value
-                       uintptr_t addr = undefinedSymbol->n_value + this->fSlide;
-                       *foundIn = this;
-                       return addr;
-               }
-               if ( (undefinedSymbol->n_desc & N_WEAK_REF) != 0 ) {
-                       // definition can't be found anywhere
-                       // if reference is weak_import, then it is ok, just return 0
-                       return 0;
-               }
-               throwSymbolNotFound(symbolName, this->getPath(), "flat namespace");
-       }
-       else {
-               // symbol requires searching images with coalesced symbols
-               if ( this->needsCoalescing() && symbolRequiresCoalescing(undefinedSymbol) ) {
-                       const Symbol* sym;
-                       if ( context.coalescedExportFinder(symbolName, &sym, foundIn) )
-                               return (*foundIn)->getExportedSymbolAddress(sym);
-                       //throwSymbolNotFound(symbolName, this->getPath(), "coalesced namespace");
-                       //fprintf(stderr, "dyld: coalesced symbol %s not found in any coalesced image, falling back to two-level lookup", symbolName);
-               }
-               
-               // two level lookup
-               void* hint = NULL;
-               ImageLoader* target = NULL;
-               uint8_t ord = GET_LIBRARY_ORDINAL(undefinedSymbol->n_desc);
-               if ( ord == EXECUTABLE_ORDINAL ) {
-                       target = context.mainExecutable;
-               }
-               else if ( ord == SELF_LIBRARY_ORDINAL ) {
-                       target = this;
-               }
-               else if ( ord == DYNAMIC_LOOKUP_ORDINAL ) {
-                       // rnielsen: HACKHACK
-                       // flat lookup
-                       const Symbol* sym;
-                       if ( context.flatExportFinder(symbolName, &sym, foundIn) )
-                               return (*foundIn)->getExportedSymbolAddress(sym);
-                       // no image has exports this symbol
-                       // either report error or hope ZeroLink can just-in-time load an image
-                       context.undefinedHandler(symbolName);
-                       // try looking again
-                       if ( context.flatExportFinder(symbolName, &sym, foundIn) )
-                               return (*foundIn)->getExportedSymbolAddress(sym);
-                       
-                       throwSymbolNotFound(symbolName, this->getPath(), "dynamic lookup");
-               }
-               else if ( ord <= fLibrariesCount ) {
-                       DependentLibrary& libInfo = fLibraries[ord-1];
-                       target = libInfo.image;
-                       if ( (target == NULL) && (((undefinedSymbol->n_desc & N_WEAK_REF) != 0) || !libInfo.required) ) {
-                               // if target library not loaded and reference is weak or library is weak return 0
-                               return 0;
-                       }
-               }
-               else {
-                       throw "corrupt binary, library ordinal too big";
-               }
-               
-               if ( target == NULL ) {
-                       fprintf(stderr, "resolveUndefined(%s) in %s\n", symbolName, this->getPath());
-                       throw "symbol not found";
-               }
-               
-               // interpret hint
-               if ( fTwoLevelHints != NULL ) {
-                       uint32_t symIndex = undefinedSymbol - fSymbolTable;
-                       int32_t undefinedIndex = symIndex - fDynamicInfo->iundefsym;
-                       if ( (undefinedIndex >= 0) && ((uint32_t)undefinedIndex < fDynamicInfo->nundefsym) ) {
-                               const struct twolevel_hint* hints = (struct twolevel_hint*)(&fLinkEditBase[fTwoLevelHints->offset]);
-                               const struct twolevel_hint* theHint = &hints[undefinedIndex];
-                               hint = (void*)theHint;
-                       }
-               }
-               
-               const Symbol* sym = target->findExportedSymbol(symbolName, hint, true, foundIn);
-               if ( sym!= NULL ) {
-                       return (*foundIn)->getExportedSymbolAddress(sym);
-               }
-               else if ( (undefinedSymbol->n_type & N_PEXT) != 0 ) {
-                       // don't know why the static linker did not eliminate the internal reference to a private extern definition
-                       *foundIn = this;
-                       return undefinedSymbol->n_value + fSlide;
-               }
-               else if ( (undefinedSymbol->n_desc & N_WEAK_REF) != 0 ) {
-                       // if definition not found and reference is weak return 0
-                       return 0;
-               }
-               
-               // nowhere to be found
-               throwSymbolNotFound(symbolName, this->getPath(), target->getPath());

        }
        }

+       return false;

 }
 
 }
 

-// returns if 'addr' is within the address range of section 'sectionIndex'
-// fSlide is not used.  'addr' is assumed to be a prebound address in this image 
-bool ImageLoaderMachO::isAddrInSection(uintptr_t addr, uint8_t sectionIndex)
+const char* ImageLoaderMachO::libPath(unsigned int index) const

 {
 {

-       uint8_t currentSectionIndex = 1;

        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
        const struct load_command* cmd = cmds;
        const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
        const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
        const struct load_command* cmd = cmds;

-       for (unsigned long i = 0; i < cmd_count; ++i) {
-               if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
-                       const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
-                       if ( (currentSectionIndex <= sectionIndex) && (sectionIndex < currentSectionIndex+seg->nsects) ) {
-                               // 'sectionIndex' is in this segment, get section info
-                               const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
-                               const struct macho_section* const section = &sectionsStart[sectionIndex-currentSectionIndex];
-                               return ( (section->addr <= addr) && (addr < section->addr+section->size) );
-                       }
-                       else {
-                               // 'sectionIndex' not in this segment, skip to next segment
-                               currentSectionIndex += seg->nsects;
-                       }
+       unsigned count = 0;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch ( cmd->cmd ) {
+                       case LC_LOAD_DYLIB:
+                       case LC_LOAD_WEAK_DYLIB:
+                       case LC_REEXPORT_DYLIB:
+                       case LC_LOAD_UPWARD_DYLIB:
+                               if ( index == count ) {
+                                       const struct dylib_command*  dylibCmd = (struct dylib_command*)cmd;
+                                       return (char*)cmd + dylibCmd->dylib.name.offset;
+                               }
+                               ++count;
+                               break;

                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
        }

-       
-       return false;
+
+       // <rdar://problem/24256354> if image linked with nothing and we implicitly added libSystem.dylib, return that
+       if ( needsAddedLibSystemDepency(libraryCount(), (macho_header*)fMachOData) ) {
+               return LIBSYSTEM_DYLIB_PATH;
+       }
+
+       return NULL;

 }
 
 }
 

-void ImageLoaderMachO::doBindExternalRelocations(const LinkContext& context, bool onlyCoalescedSymbols)
-{
-       const uintptr_t relocBase = this->getRelocBase();
-       const bool twoLevel = this->usesTwoLevelNameSpace();
-       const bool prebound = this->isPrebindable();
-       
-       // if there are __TEXT fixups, temporarily make __TEXT writable
-       if ( fTextSegmentWithFixups != NULL ) 
-               fTextSegmentWithFixups->tempWritable();

 
 

-       // cache last lookup
-       const struct macho_nlist*       lastUndefinedSymbol = 0;
-       uintptr_t                                       symbolAddr = 0;
-       ImageLoader*                            image = NULL;
-       
-       // loop through all external relocation records and bind each
-       const relocation_info* const relocsStart = (struct relocation_info*)(&fLinkEditBase[fDynamicInfo->extreloff]);
-       const relocation_info* const relocsEnd = &relocsStart[fDynamicInfo->nextrel];
-       for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
-               if (reloc->r_length == RELOC_SIZE) {
-                       switch(reloc->r_type) {
-                               case POINTER_RELOC:
-                                       {
-                                               const struct macho_nlist* undefinedSymbol = &fSymbolTable[reloc->r_symbolnum];
-                                               // if only processing coalesced symbols and this one does not require coalesceing, skip to next
-                                               if ( onlyCoalescedSymbols && !symbolRequiresCoalescing(undefinedSymbol) )
-                                                       continue;
-                                               uintptr_t* location = ((uintptr_t*)(reloc->r_address + relocBase));
-                                               uintptr_t value = *location;
-                                       #if __i386__
-                                               if ( reloc->r_pcrel ) {
-                                                       value += (uintptr_t)location + 4 - fSlide;
-                                               }
-                                       #endif
-                                               if ( prebound ) {
-                                                       // we are doing relocations, so prebinding was not usable
-                                                       // in a prebound executable, the n_value field of an undefined symbol is set to the address where the symbol was found when prebound
-                                                       // so, subtracting that gives the initial displacement which we need to add to the newly found symbol address
-                                                       // if mach-o relocation structs had an "addend" field this complication would not be necessary.
-                                                       if ( ((undefinedSymbol->n_type & N_TYPE) == N_SECT) && ((undefinedSymbol->n_desc & N_WEAK_DEF) != 0) ) {
-                                                               // weak symbols need special casing, since *location may have been prebound to a definition in another image.
-                                                               // If *location is currently prebound to somewhere in the same section as the weak definition, we assume 
-                                                               // that we can subtract off the weak symbol address to get the addend.
-                                                               // If prebound elsewhere, we've lost the addend and have to assume it is zero.
-                                                               // The prebinding to elsewhere only happens with 10.4+ update_prebinding which only operates on a small set of Apple dylibs
-                                                               if ( (value == undefinedSymbol->n_value) || this->isAddrInSection(value, undefinedSymbol->n_sect) )
-                                                                       value -= undefinedSymbol->n_value;
-                                                               else
-                                                                       value = 0;
-                                                       } 
-                                                       else {
-                                                               // is undefined or non-weak symbol, so do subtraction to get addend
-                                                               value -= undefinedSymbol->n_value;
-                                                       }
-                                               }
-                                               // if undefinedSymbol is same as last time, then symbolAddr and image will resolve to the same too
-                                               if ( undefinedSymbol != lastUndefinedSymbol ) {
-                                                       symbolAddr = this->resolveUndefined(context, undefinedSymbol, twoLevel, &image);
-                                                       lastUndefinedSymbol = undefinedSymbol;
-                                               }
-                                               if ( context.verboseBind ) {
-                                                       const char *path = NULL;
-                                                       if(NULL != image) {
-                                                               path = image->getShortName();
-                                                       }
-                                                       if(0 == value) {
-                                                               fprintf(stderr, "dyld: bind: %s:0x%08lx = %s:%s, *0x%08lx = 0x%08lx\n",
-                                                                               this->getShortName(), (uintptr_t)location,
-                                                                               path, &fStrings[undefinedSymbol->n_un.n_strx], (uintptr_t)location, symbolAddr);
-                                                       }
-                                                       else {
-                                                               fprintf(stderr, "dyld: bind: %s:0x%08lx = %s:%s, *0x%08lx = 0x%08lx + %ld\n",
-                                                                               this->getShortName(), (uintptr_t)location,
-                                                                               path, &fStrings[undefinedSymbol->n_un.n_strx], (uintptr_t)location, symbolAddr, value);
-                                                       }
-                                               }
-                                               value += symbolAddr;
-                                       #if __i386__
-                                               if ( reloc->r_pcrel ) {
-                                                       *location = value - ((uintptr_t)location + 4);
-                                               }
-                                               else {
-                                                       // don't dirty page if prebound value was correct
-                                                       if ( !prebound || (*location != value) )
-                                                               *location = value; 
-                                               }
-                                       #else
-                                               // don't dirty page if prebound value was correct
-                                               if ( !prebound || (*location != value) )
-                                                       *location = value; 
-                                       #endif
-                                       }
-                                       break;
-                               default:
-                                       throw "unknown external relocation type";
-                       }
-               }
-               else {
-                       throw "bad external relocation length";
-               }
-       }
-       
-       // if there were __TEXT fixups, restore write protection
-       if ( fTextSegmentWithFixups != NULL ) {
-               fTextSegmentWithFixups->setPermissions();
-               sys_icache_invalidate((void*)fTextSegmentWithFixups->getActualLoadAddress(), fTextSegmentWithFixups->getSize());
-       }
-       
-       // update stats
-       fgTotalBindFixups += fDynamicInfo->nextrel;
+void __attribute__((noreturn)) ImageLoaderMachO::throwSymbolNotFound(const LinkContext& context, const char* symbol, 
+                                                                                                                                       const char* referencedFrom, const char* fromVersMismatch,
+                                                                                                                                       const char* expectedIn)
+{
+       // record values for possible use by CrashReporter or Finder
+       (*context.setErrorStrings)(DYLD_EXIT_REASON_SYMBOL_MISSING, referencedFrom, expectedIn, symbol);
+       dyld::throwf("Symbol not found: %s\n  Referenced from: %s%s\n  Expected in: %s\n",
+                                       symbol, referencedFrom, fromVersMismatch, expectedIn);

 }
 
 const mach_header* ImageLoaderMachO::machHeader() const
 }
 
 const mach_header* ImageLoaderMachO::machHeader() const


@@ -1948,789 +1957,900 @@ uintptr_t ImageLoaderMachO::getSlide() const
 }
 
 // hmm. maybe this should be up in ImageLoader??
 }
 
 // hmm. maybe this should be up in ImageLoader??

-const void* ImageLoaderMachO::getBaseAddress() const
-{
-       Segment* seg = fSegments[0];
-       return (const void*)seg->getActualLoadAddress();
+const void* ImageLoaderMachO::getEnd() const
+{
+       uintptr_t lastAddress = 0;
+       for(unsigned int i=0; i < fSegmentsCount; ++i) {
+               uintptr_t segEnd = segActualEndAddress(i);
+               if ( strcmp(segName(i), "__UNIXSTACK") != 0 ) {
+                       if ( segEnd > lastAddress )
+                               lastAddress = segEnd;
+               }
+       }
+       return (const void*)lastAddress;
+}
+
+uintptr_t ImageLoaderMachO::bindLocation(const LinkContext& context, uintptr_t baseVMAddress,
+                                         uintptr_t location, uintptr_t value,
+                                         uint8_t type, const char* symbolName,
+                                         intptr_t addend, const char* inPath, const char* toPath, const char* msg,
+                                         ExtraBindData *extraBindData, uintptr_t slide)
+{
+    auto logBind = [&]() {
+        if ( !context.verboseBind )
+            return;
+        if ( addend != 0 ) {
+            dyld::log("dyld: %sbind: %s:0x%08lX = %s:%s, *0x%08lX = 0x%08lX + %ld\n",
+                      msg, shortName(inPath), (uintptr_t)location,
+                      ((toPath != NULL) ? shortName(toPath) : "<missing weak_import>"),
+                      symbolName, (uintptr_t)location, value, addend);
+        } else {
+            dyld::log("dyld: %sbind: %s:0x%08lX = %s:%s, *0x%08lX = 0x%08lX\n",
+                      msg, shortName(inPath), (uintptr_t)location,
+                      ((toPath != NULL) ? shortName(toPath) : "<missing weak_import>"),
+                      symbolName, (uintptr_t)location, value);
+        }
+    };
+
+
+#if LOG_BINDINGS
+//     dyld::logBindings("%s: %s\n", targetImage->getShortName(), symbolName);
+#endif
+       
+       // do actual update
+       uintptr_t* locationToFix = (uintptr_t*)location;
+       uint32_t* loc32;
+       uintptr_t newValue = value+addend;
+       uint32_t value32;
+       switch (type) {
+               case BIND_TYPE_POINTER:
+            logBind();
+                       // test first so we don't needless dirty pages
+                       if ( *locationToFix != newValue )
+                               *locationToFix = newValue;
+                       break;
+        case BIND_TYPE_TEXT_ABSOLUTE32:
+            logBind();
+                       loc32 = (uint32_t*)locationToFix;
+                       value32 = (uint32_t)newValue;
+                       if ( *loc32 != value32 )
+                               *loc32 = value32;
+                       break;
+        case BIND_TYPE_TEXT_PCREL32:
+            logBind();
+                       loc32 = (uint32_t*)locationToFix;
+                       value32 = (uint32_t)(newValue - (((uintptr_t)locationToFix) + 4));
+                       if ( *loc32 != value32 )
+                               *loc32 = value32;
+            break;
+        case BIND_TYPE_THREADED_BIND:
+            logBind();
+            // test first so we don't needless dirty pages
+            if ( *locationToFix != newValue )
+                *locationToFix = newValue;
+            break;
+        case BIND_TYPE_THREADED_REBASE: {
+            // Regular pointer which needs to fit in 51-bits of value.
+            // C++ RTTI uses the top bit, so we'll allow the whole top-byte
+            // and the signed-extended bottom 43-bits to be fit in to 51-bits.
+            uint64_t top8Bits = *locationToFix & 0x0007F80000000000ULL;
+            uint64_t bottom43Bits = *locationToFix & 0x000007FFFFFFFFFFULL;
+            uint64_t targetValue = ( top8Bits << 13 ) | (((intptr_t)(bottom43Bits << 21) >> 21) & 0x00FFFFFFFFFFFFFF);
+            newValue = (uintptr_t)(targetValue + slide);
+            if ( context.verboseRebase ) {
+                dyld::log("dyld: rebase: %s:*0x%08lX += 0x%08lX = 0x%08lX\n", shortName(inPath), (uintptr_t)locationToFix, slide, newValue);
+            }
+            *locationToFix = newValue;
+                       break;
+        }
+               default:
+                       dyld::throwf("bad bind type %d", type);
+       }
+       
+       // update statistics
+       ++fgTotalBindFixups;
+       
+       return newValue;

 }
 
 }
 

-uintptr_t ImageLoaderMachO::bindIndirectSymbol(uintptr_t* ptrToBind, const struct macho_section* sect, const char* symbolName, uintptr_t targetAddr, ImageLoader* targetImage, const LinkContext& context)
-{
-       if ( context.verboseBind ) {
-               const char* path = NULL;
-               if ( targetImage != NULL )
-                       path = targetImage->getShortName();
-               fprintf(stderr, "dyld: bind: %s:%s$%s = %s:%s, *0x%08lx = 0x%08lx\n",
-                               this->getShortName(), symbolName, (((sect->flags & SECTION_TYPE)==S_NON_LAZY_SYMBOL_POINTERS) ? "non_lazy_ptr" : "lazy_ptr"),
-                               path, symbolName, (uintptr_t)ptrToBind, targetAddr);
-       }
-       if ( context.bindingHandler != NULL ) {
-               const char* path = NULL;
-               if ( targetImage != NULL )
-                       path = targetImage->getShortName();
-               targetAddr = (uintptr_t)context.bindingHandler(path, symbolName, (void *)targetAddr);
-       }
+
+
+
+
+#if SUPPORT_OLD_CRT_INITIALIZATION
+// first 16 bytes of "start" in crt1.o

 #if __i386__
 #if __i386__

-       // i386 has special self-modifying stubs that change from "CALL rel32" to "JMP rel32"
-       if ( ((sect->flags & SECTION_TYPE) == S_SYMBOL_STUBS) && ((sect->flags & S_ATTR_SELF_MODIFYING_CODE) != 0) && (sect->reserved2 == 5) ) {
-               uint8_t* const jmpTableEntryToPatch = (uint8_t*)ptrToBind;
-               uint32_t rel32 = targetAddr - (((uint32_t)ptrToBind)+5);
-               //fprintf(stderr, "rewriting stub at %p\n", jmpTableEntryToPatch);
-               jmpTableEntryToPatch[0] = 0xE9; // JMP rel32
-               jmpTableEntryToPatch[1] = rel32 & 0xFF;
-               jmpTableEntryToPatch[2] = (rel32 >> 8) & 0xFF;
-               jmpTableEntryToPatch[3] = (rel32 >> 16) & 0xFF;
-               jmpTableEntryToPatch[4] = (rel32 >> 24) & 0xFF;
-       }
-       else
+       static uint8_t sStandardEntryPointInstructions[16] = { 0x6a, 0x00, 0x89, 0xe5, 0x83, 0xe4, 0xf0, 0x83, 0xec, 0x10, 0x8b, 0x5d, 0x04, 0x89, 0x5c, 0x24 };

 #endif
 #endif

-       *ptrToBind = targetAddr;
-       return targetAddr;
-}
+#endif
+
+struct DATAdyld {
+       void*                   dyldLazyBinder;         // filled in at launch by dyld to point into dyld to &stub_binding_helper
+       void*                   dyldFuncLookup;         // filled in at launch by dyld to point into dyld to &_dyld_func_lookup
+       // the following only exist in main executables built for 10.5 or later
+       ProgramVars             vars;
+};

 
 

+// These are defined in dyldStartup.s
+extern "C" void stub_binding_helper();
+extern "C" int _dyld_func_lookup(const char* name, void** address);

 
 

-uintptr_t ImageLoaderMachO::doBindLazySymbol(uintptr_t* lazyPointer, const LinkContext& context)
+void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)

 {
 {

-       // scan for all non-lazy-pointer sections
-       const bool twoLevel = this->usesTwoLevelNameSpace();
-       const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
+       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* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];

-       const struct load_command* cmd = cmds;
-       const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[fDynamicInfo->indirectsymoff];
-       for (uint32_t i = 0; i < cmd_count; ++i) {
-               switch (cmd->cmd) {
-                       case LC_SEGMENT_COMMAND:
-                               {
-                                       const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+       const struct load_command* cmd;
+       // There used to be some optimizations to skip this section scan, but we need to handle the 
+       // __dyld section in libdyld.dylib, so everything needs to be scanned for now.
+       // <rdar://problem/10910062> CrashTracer: 1,295 crashes in bash at bash: getenv
+       if ( true ) {
+               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;
+                               if ( strncmp(seg->segname, "__DATA", 6) == 0 ) {

                                        const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
                                        const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
                                        for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
                                        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;
-                                               uint32_t symbolIndex = INDIRECT_SYMBOL_LOCAL;
-                                               if ( type == S_LAZY_SYMBOL_POINTERS ) {
-                                                       const uint32_t pointerCount = sect->size / sizeof(uintptr_t);
-                                                       uintptr_t* const symbolPointers = (uintptr_t*)(sect->addr + fSlide);
-                                                       if ( (lazyPointer >= symbolPointers) && (lazyPointer < &symbolPointers[pointerCount]) ) {
-                                                               const uint32_t indirectTableOffset = sect->reserved1;
-                                                               const uint32_t lazyIndex = lazyPointer - symbolPointers;
-                                                               symbolIndex = indirectTable[indirectTableOffset + lazyIndex];
+                                               if ( strcmp(sect->sectname, "__dyld" ) == 0 ) {
+                                                       struct DATAdyld* dd = (struct DATAdyld*)(sect->addr + fSlide);
+                               #if !__arm64__ && !__ARM_ARCH_7K__
+                                                       if ( sect->size > offsetof(DATAdyld, dyldLazyBinder) ) {
+                                                               if ( dd->dyldLazyBinder != (void*)&stub_binding_helper )
+                                                                       dd->dyldLazyBinder = (void*)&stub_binding_helper;

                                                        }
                                                        }

-                                               }
-                                       #if __i386__
-                                               else if ( (type == S_SYMBOL_STUBS) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
-                                                       // 5 bytes stubs on i386 are new "fast stubs"
-                                                       uint8_t* const jmpTableBase = (uint8_t*)(sect->addr + fSlide);
-                                                       uint8_t* const jmpTableEnd = jmpTableBase + sect->size;
-                                                       // initial CALL instruction in jump table leaves pointer to next entry, so back up
-                                                       uint8_t* const jmpTableEntryToPatch = ((uint8_t*)lazyPointer) - 5;  
-                                                       lazyPointer = (uintptr_t*)jmpTableEntryToPatch; 
-                                                       if ( (jmpTableEntryToPatch >= jmpTableBase) && (jmpTableEntryToPatch < jmpTableEnd) ) {
-                                                               const uint32_t indirectTableOffset = sect->reserved1;
-                                                               const uint32_t entryIndex = (jmpTableEntryToPatch - jmpTableBase)/5;
-                                                               symbolIndex = indirectTable[indirectTableOffset + entryIndex];
+                               #endif // !__arm64__
+                                                       // <rdar://problem/40352925> Add work around for existing apps that have deprecated __dyld section
+                                                       const char* installNm = this->getInstallPath();
+                                                       if ( (mh->filetype != MH_DYLIB) || (installNm == NULL) || (strcmp(installNm, "/usr/lib/system/libdyld.dylib") != 0) ) {
+                                               #if TARGET_OS_OSX
+                                                               // don't allow macOS apps build with 10.14 or later SDK and targeting 10.8 or later to have a __dyld section
+                                                               if ( (minOSVersion() >= 0x000a0800) && (sdkVersion() >= 0x000a0e00) )
+                                                                       dyld::throwf("__dyld section not supported in %s", this->getPath());
+                                               #endif
+                                               #if TARGET_OS_IOS || TARGET_OS_TV
+                                                               // don't allow iOS apps build with 12.0 or later SDK to have a __dyld section
+                                                               if ( sdkVersion() >= 0x000c0000 )
+                                                                       dyld::throwf("__dyld section not supported in %s", this->getPath());
+                                               #endif
+                                               #if TARGET_OS_WATCH
+                                                               if ( sdkVersion() >= 0x00050000 )
+                                                                       dyld::throwf("__dyld section not supported in %s", this->getPath());
+                                               #endif
+                                                       }
+                                                       if ( sect->size > offsetof(DATAdyld, dyldFuncLookup) ) {
+                                                               if ( dd->dyldFuncLookup != (void*)&_dyld_func_lookup )
+                                                                       dd->dyldFuncLookup = (void*)&_dyld_func_lookup;
+                                                       }
+                                                       if ( mh->filetype == MH_EXECUTE ) {
+                                                               // there are two ways to get the program variables
+                                                               if ( (sect->size > offsetof(DATAdyld, vars)) && (dd->vars.mh == mh) ) {
+                                                                       // some really old binaries have space for vars, but it is zero filled
+                                                                       // main executable has 10.5 style __dyld section that has program variable pointers
+                                                                       context.setNewProgramVars(dd->vars);
+                                                               }
+                                                               else {
+                                                                       // main executable is pre-10.5 and requires the symbols names to be looked up
+                                                                       this->lookupProgramVars(context);
+                               #if SUPPORT_OLD_CRT_INITIALIZATION
+                                                                       // If the first 16 bytes of the entry point's instructions do not 
+                                                                       // match what crt1.o supplies, then the program has a custom entry point.
+                                                                       // This means it might be doing something that needs to be executed before 
+                                                                       // initializers are run. 
+                                                                       if ( memcmp(this->getEntryFromLC_UNIXTHREAD(), sStandardEntryPointInstructions, 16) != 0 ) {
+                                                                               if ( context.verboseInit )
+                                                                                       dyld::log("dyld: program uses non-standard entry point so delaying running of initializers\n");
+                                                                               context.setRunInitialzersOldWay();
+                                                                       }
+                               #endif
+                                                               }
+                                                       }
+                                                       else if ( mh->filetype == MH_DYLIB ) {
+                                                               const char* installPath = this->getInstallPath();
+                                                               if ( (installPath != NULL) && (strncmp(installPath, "/usr/lib/", 9) == 0) ) {
+                                                                       if ( sect->size > offsetof(DATAdyld, vars) ) {
+                                                                               // use ProgramVars from libdyld.dylib but tweak mh field to correct value
+                                                                               dd->vars.mh = context.mainExecutable->machHeader();
+                                                                               context.setNewProgramVars(dd->vars);
+                                                                       }
+                                                               }

                                                        }
                                                }
                                                        }
                                                }

-                                       #endif
-                                               if ( symbolIndex != INDIRECT_SYMBOL_ABS && symbolIndex != INDIRECT_SYMBOL_LOCAL ) {
-                                                       const char* symbolName = &fStrings[fSymbolTable[symbolIndex].n_un.n_strx];
-                                                       ImageLoader* image = NULL;
-                                                       uintptr_t symbolAddr = this->resolveUndefined(context,  &fSymbolTable[symbolIndex], twoLevel, &image);
-                                                       symbolAddr = this->bindIndirectSymbol(lazyPointer, sect, symbolName, symbolAddr, image,  context);
-                                                       ++fgTotalLazyBindFixups;
-                                                       return symbolAddr;
+                                               else if ( (strcmp(sect->sectname, "__program_vars" ) == 0) && (mh->filetype == MH_EXECUTE) ) {
+                                                       // this is a Mac OS X 10.6 or later main executable 
+                                                       struct ProgramVars* pv = (struct ProgramVars*)(sect->addr + fSlide);
+                                                       context.setNewProgramVars(*pv);

                                                }
                                        }
                                }
                                                }
                                        }
                                }

-                               break;
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

                }
                }

-               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       throw "lazy pointer not found";

 }
 
 }
 

+                                                                       
+void ImageLoaderMachO::lookupProgramVars(const LinkContext& context) const
+{
+       ProgramVars vars = context.programVars;
+       const ImageLoader::Symbol* sym;
+       
+       // get mach header directly
+       vars.mh = (macho_header*)fMachOData;
+       
+       // lookup _NXArgc
+       sym = this->findShallowExportedSymbol("_NXArgc", NULL);
+       if ( sym != NULL )
+               vars.NXArgcPtr = (int*)this->getExportedSymbolAddress(sym, context, this, false, NULL);
+               
+       // lookup _NXArgv
+       sym = this->findShallowExportedSymbol("_NXArgv", NULL);
+       if ( sym != NULL )
+               vars.NXArgvPtr = (const char***)this->getExportedSymbolAddress(sym, context, this, false, NULL);
+               
+       // lookup _environ
+       sym = this->findShallowExportedSymbol("_environ", NULL);
+       if ( sym != NULL )
+               vars.environPtr = (const char***)this->getExportedSymbolAddress(sym, context, this, false, NULL);
+               
+       // lookup __progname
+       sym = this->findShallowExportedSymbol("___progname", NULL);
+       if ( sym != NULL )
+               vars.__prognamePtr = (const char**)this->getExportedSymbolAddress(sym, context, this, false, NULL);
+               
+       context.setNewProgramVars(vars);
+}
+
+
+bool ImageLoaderMachO::usablePrebinding(const LinkContext& context) const
+{
+       // if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
+       if ( ((this->isPrebindable() && (this->getSlide() == 0)) || fInSharedCache)
+               && this->usesTwoLevelNameSpace()
+#if !USES_CHAINED_BINDS
+               && this->allDependentLibrariesAsWhenPreBound()
+#endif
+                ) {
+               // allow environment variables to disable prebinding
+               if ( context.bindFlat )
+                       return false;
+               switch ( context.prebindUsage ) {
+                       case kUseAllPrebinding:
+                               return true;
+                       case kUseSplitSegPrebinding:
+                               return this->fIsSplitSeg;
+                       case kUseAllButAppPredbinding:
+                               return (this != context.mainExecutable);
+                       case kUseNoPrebinding:
+                               return false;
+               }
+       }
+       return false;
+}
+
+static void *stripPointer(void *ptr) {
+#if __has_feature(ptrauth_calls)
+    return __builtin_ptrauth_strip(ptr, ptrauth_key_asia);
+#else
+    return ptr;
+#endif
+}

 
 
 
 

+void ImageLoaderMachO::doImageInit(const LinkContext& context)
+{
+       if ( fHasDashInit ) {
+               const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
+                       switch (cmd->cmd) {
+                               case LC_ROUTINES_COMMAND:
+                                       Initializer func = (Initializer)(((struct macho_routines_command*)cmd)->init_address + fSlide);
+#if __has_feature(ptrauth_calls)
+                                       func = (Initializer)__builtin_ptrauth_sign_unauthenticated((void*)func, ptrauth_key_asia, 0);
+#endif
+                                       // <rdar://problem/8543820&9228031> verify initializers are in image
+                                       if ( ! this->containsAddress(stripPointer((void*)func)) ) {
+                                               dyld::throwf("initializer function %p not in mapped image for %s\n", func, this->getPath());
+                                       }
+                                       if ( ! dyld::gProcessInfo->libSystemInitialized ) {
+                                               // <rdar://problem/17973316> libSystem initializer must run first
+                                               dyld::throwf("-init function in image (%s) that does not link with libSystem.dylib\n", this->getPath());
+                                       }
+                                       if ( context.verboseInit )
+                                               dyld::log("dyld: calling -init function %p in %s\n", func, this->getPath());
+                                       {
+                                               dyld3::ScopedTimer(DBG_DYLD_TIMING_STATIC_INITIALIZER, (uint64_t)fMachOData, (uint64_t)func, 0);
+                                               func(context.argc, context.argv, context.envp, context.apple, &context.programVars);
+                                       }
+                                       break;
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+               }
+       }
+}

 
 

-void ImageLoaderMachO::doBindIndirectSymbolPointers(const LinkContext& context, BindingLaziness bindness, bool onlyCoalescedSymbols)
+void ImageLoaderMachO::doModInitFunctions(const LinkContext& context)

 {
 {

-       // scan for all non-lazy-pointer sections 
-       const bool twoLevel = this->usesTwoLevelNameSpace();
-       const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
-       const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
-       const struct load_command* cmd = cmds;
-       const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[fDynamicInfo->indirectsymoff];
-       for (uint32_t i = 0; i < cmd_count; ++i) {
-               switch (cmd->cmd) {
-                       case LC_SEGMENT_COMMAND:
-                               {
-                                       const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
-                                       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;
-                                               uint32_t elementSize = sizeof(uintptr_t);
-                                               uint32_t elementCount = sect->size / elementSize;
-                                               if ( type == S_NON_LAZY_SYMBOL_POINTERS ) {
-                                                       if ( (bindness == kLazyOnly) || (bindness == kLazyOnlyNoDependents) )
-                                                               continue;
-                                               }
-                                               else if ( type == S_LAZY_SYMBOL_POINTERS ) {
-                                                       // process each symbol pointer in this section
-                                                       fgTotalPossibleLazyBindFixups += elementCount;
-                                                       if ( bindness == kNonLazyOnly )
-                                                               continue;
-                                               }
-                               #if __i386__
-                                               else if ( (type == S_SYMBOL_STUBS) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
-                                                       // process each jmp entry in this section
-                                                       elementCount = sect->size / 5;
-                                                       elementSize = 5;
-                                                       fgTotalPossibleLazyBindFixups += elementCount;
-                                                       if ( bindness == kNonLazyOnly )
-                                                               continue;
-                                               }
-                               #endif
-                                               else {
-                                                       continue;
-                                               }
-                                               const uint32_t indirectTableOffset = sect->reserved1;
-                                               uint8_t* ptrToBind = (uint8_t*)(sect->addr + fSlide);
-                                               for (uint32_t j=0; j < elementCount; ++j, ptrToBind += elementSize) {
-                                                       uint32_t symbolIndex = indirectTable[indirectTableOffset + j];
-                                                       if ( symbolIndex == INDIRECT_SYMBOL_LOCAL) {
-                                                               *((uintptr_t*)ptrToBind) += this->fSlide;
+       if ( fHasInitializers ) {
+               const uint32_t cmd_count = ((macho_header*)fMachOData)->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_MOD_INIT_FUNC_POINTERS ) {
+                                               Initializer* inits = (Initializer*)(sect->addr + fSlide);
+                                               const size_t count = sect->size / sizeof(uintptr_t);
+                                               // <rdar://problem/23929217> Ensure __mod_init_func section is within segment
+                                               if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
+                                                       dyld::throwf("__mod_init_funcs section has malformed address range for %s\n", this->getPath());
+                                               for (size_t j=0; j < count; ++j) {
+                                                       Initializer func = inits[j];
+                                                       // <rdar://problem/8543820&9228031> verify initializers are in image
+                                                       if ( ! this->containsAddress(stripPointer((void*)func)) ) {
+                                                               dyld::throwf("initializer function %p not in mapped image for %s\n", func, this->getPath());

                                                        }
                                                        }

-                                                       else if ( symbolIndex == INDIRECT_SYMBOL_ABS) {
-                                                               // do nothing since already has absolute address
+                                                       if ( ! dyld::gProcessInfo->libSystemInitialized ) {
+                                                               // <rdar://problem/17973316> libSystem initializer must run first
+                                                               const char* installPath = getInstallPath();
+                                                               if ( (installPath == NULL) || (strcmp(installPath, LIBSYSTEM_DYLIB_PATH) != 0) )
+                                                                       dyld::throwf("initializer in image (%s) that does not link with libSystem.dylib\n", this->getPath());

                                                        }
                                                        }

-                                                       else {
-                                                               const struct macho_nlist* sym = &fSymbolTable[symbolIndex];
-                                                               if ( symbolIndex == 0 ) {
-                                                                       // This could be rdar://problem/3534709 
-                                                                       if ( ((const macho_header*)fMachOData)->filetype == MH_EXECUTE ) {
-                                                                               static bool alreadyWarned = false;
-                                                                               if ( (sym->n_type & N_TYPE) != N_UNDF ) {
-                                                                                       // The indirect table parallels the (non)lazy pointer sections.  For
-                                                                                       // instance, to find info about the fifth lazy pointer you look at the
-                                                                                       // fifth entry in the indirect table.  (try otool -Iv on a file).
-                                                                                       // The entry in the indirect table contains an index into the symbol table.
-
-                                                                                       // The bug in ld caused the entry in the indirect table to be zero
-                                                                                       // (instead of a magic value that means a local symbol).  So, if the
-                                                                                       // symbolIndex == 0, we may be encountering the bug, or 0 may be a valid
-                                                                                       // symbol table index. The check I put in place is to see if the zero'th
-                                                                                       // symbol table entry is an import entry (usually it is a local symbol
-                                                                                       // definition).
-                                                                                       if ( context.verboseWarnings && !alreadyWarned ) {
-                                                                                               fprintf(stderr, "dyld: malformed executable '%s', skipping indirect symbol to %s\n",
-                                                                                                               this->getPath(), &fStrings[sym->n_un.n_strx]);
-                                                                                               alreadyWarned = true;
-                                                                                       }
-                                                                                       continue;
-                                                                               }
-                                                                       }
-                                                               }
-                                                               ImageLoader *image = NULL;
-                                                               // if only processing coalesced symbols and this one does not require coalesceing, skip to next
-                                                               if ( onlyCoalescedSymbols && !symbolRequiresCoalescing(sym) )
-                                                                       continue;
-                                                               uintptr_t symbolAddr;
-                                                                       symbolAddr = resolveUndefined(context, sym, twoLevel, &image);
-                                                                       
-                                                               // update pointer
-                                                               symbolAddr = this->bindIndirectSymbol((uintptr_t*)ptrToBind, sect, &fStrings[sym->n_un.n_strx], symbolAddr, image,  context);
+                                                       if ( context.verboseInit )
+                                                               dyld::log("dyld: calling initializer function %p in %s\n", func, this->getPath());
+                                                       bool haveLibSystemHelpersBefore = (dyld::gLibSystemHelpers != NULL);
+                                                       {
+                                                               dyld3::ScopedTimer(DBG_DYLD_TIMING_STATIC_INITIALIZER, (uint64_t)fMachOData, (uint64_t)func, 0);
+                                                               func(context.argc, context.argv, context.envp, context.apple, &context.programVars);
+                                                       }
+                                                       bool haveLibSystemHelpersAfter = (dyld::gLibSystemHelpers != NULL);
+                                                       if ( !haveLibSystemHelpersBefore && haveLibSystemHelpersAfter ) {
+                                                               // now safe to use malloc() and other calls in libSystem.dylib
+                                                               dyld::gProcessInfo->libSystemInitialized = true;

                                                        }
                                                }
                                                        }
                                                }

-                                               // update stats
-                                               fgTotalBindFixups += elementCount;

                                        }
                                }
                                        }
                                }

-                               break;
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

                }
                }

-               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
 }
 
        }
 }
 

-/*
- * The address of these symbols are written in to the (__DATA,__dyld) section
- * at the following offsets:
- *     at offset 0     stub_binding_helper_interface
- *     at offset 4     _dyld_func_lookup
- *     at offset 8     start_debug_thread
- * The 'C' types (if any) for these symbols are ignored here and all are
- * declared as longs so the assignment of their address in to the section will
- * not require a cast.  stub_binding_helper_interface is really a label in the
- * assembly code interface for the stub binding.  It does not have a meaningful 
- * 'C' type.  _dyld_func_lookup is the routine in dyld_libfuncs.c.
- * start_debug_thread is the routine in debug.c.
- *
- * For ppc the image's stub_binding_binding_helper is read from:
- *     at offset 20    the image's stub_binding_binding_helper address
- * and saved into to the image structure.
- */
-struct DATAdyld {
-       void*   dyldLazyBinder;         // filled in at launch by dyld to point into dyld to &stub_binding_helper_interface
-       void*   dyldFuncLookup;         // filled in at launch by dyld to point into dyld to &_dyld_func_lookup
-       void*   startDebugThread;   // debugger interface ???
-       void*   debugPort;                      // debugger interface ???
-       void*   debugThread;            // debugger interface ???
-       void*   stubBindHelper;         // filled in at static link time to point to stub helper in image
-       void*   coreDebug;                      // ???
-};
-
-// These are defined in dyldStartup.s
-extern "C" void stub_binding_helper();
-extern "C" bool dyld_func_lookup(const char* name, uintptr_t* address);
-extern "C" void fast_stub_binding_helper_interface();
-

 
 

-void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)
+
+void ImageLoaderMachO::doGetDOFSections(const LinkContext& context, std::vector<ImageLoader::DOFInfo>& dofs)

 {
 {

-       if ( fDATAdyld != NULL ) {
-               struct DATAdyld* dd = (struct DATAdyld*)(fDATAdyld->addr + fSlide);
-               if ( fDATAdyld->size > offsetof(DATAdyld, dyldLazyBinder) ) {
-                       if ( dd->dyldLazyBinder != (void*)&stub_binding_helper )
-                               dd->dyldLazyBinder = (void*)&stub_binding_helper;
-               }
-               if ( fDATAdyld->size > offsetof(DATAdyld, dyldFuncLookup) ) {
-                       if ( dd->dyldFuncLookup != (void*)&dyld_func_lookup )
-                               dd->dyldFuncLookup = (void*)&dyld_func_lookup;
-               }
-               //if ( fDATAdyld->size > offsetof(DATAdyld, startDebugThread) ) 
-               //      dd->startDebugThread = &start_debug_thread;
-#ifdef __ppc__
-               //if ( fDATAdyld->size > offsetof(DATAdyld, stubBindHelper) )
-               //      save = dd->stubBindHelper;      
-#endif
-       }
-#if __i386__
-       if ( ! this->usablePrebinding(context) || !this->usesTwoLevelNameSpace() ) {
-               // reset all "fast" stubs
+       if ( fHasDOFSections ) {
+               // walk load commands (mapped in at start of __TEXT segment)

                const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
                        switch (cmd->cmd) {
                                case LC_SEGMENT_COMMAND:
                const uint32_t cmd_count = ((macho_header*)fMachOData)->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) {
                        switch (cmd->cmd) {
                                case 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) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
-                                                       // reset each jmp entry in this section
-                                                       uint8_t* start = (uint8_t*)(sect->addr + this->fSlide);
-                                                       uint8_t* end = start + sect->size;
-                                                       uintptr_t dyldHandler = (uintptr_t)&fast_stub_binding_helper_interface;
-                                                       for (uint8_t* entry = start; entry < end; entry += 5) {
-                                                               uint32_t rel32 = dyldHandler - (((uint32_t)entry)+5);
-                                                               entry[0] = 0xE8; // CALL rel32
-                                                               entry[1] = rel32 & 0xFF;
-                                                               entry[2] = (rel32 >> 8) & 0xFF;
-                                                               entry[3] = (rel32 >> 16) & 0xFF;
-                                                               entry[4] = (rel32 >> 24) & 0xFF;
+                                       {
+                                               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) {
+                                                       if ( (sect->flags & SECTION_TYPE) == S_DTRACE_DOF ) {
+                                                               // <rdar://problem/23929217> Ensure section is within segment
+                                                               if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
+                                                                       dyld::throwf("DOF section has malformed address range for %s\n", this->getPath());
+                                                               ImageLoader::DOFInfo info;
+                                                               info.dof                        = (void*)(sect->addr + fSlide);
+                                                               info.imageHeader        = this->machHeader();
+                                                               info.imageShortName = this->getShortName();
+                                                               dofs.push_back(info);

                                                        }
                                                }
                                        }
                                                        }
                                                }
                                        }

-                               }
+                                       break;

                        }
                        cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
                }
        }
                        }
                        cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
                }
        }

-#endif
-}
+}      

 
 

-bool ImageLoaderMachO::usablePrebinding(const LinkContext& context) const
-{
-       // if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
-       if ( this->isPrebindable() && this->allDependentLibrariesAsWhenPreBound() && (this->getSlide() == 0) ) {
-               // allow environment variables to disable prebinding
-               if ( context.bindFlat )
-                       return false;
-               switch ( context.prebindUsage ) {
-                       case kUseAllPrebinding:
-                               return true;
-                       case kUseSplitSegPrebinding:
-                               return this->fIsSplitSeg;
-                       case kUseAllButAppPredbinding:
-                               return (this != context.mainExecutable);
-                       case kUseNoPrebinding:
-                               return false;
-               }
-       }
-       return false;
-}

 
 

-void ImageLoaderMachO::doBind(const LinkContext& context, BindingLaziness bindness)
+bool ImageLoaderMachO::doInitialization(const LinkContext& context)

 {
 {

-       // set dyld entry points in image
-       this->setupLazyPointerHandler(context);
+       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 be imports rebound (even if correctly prebound)
-       if ( this->usablePrebinding(context) && this->usesTwoLevelNameSpace() ) {
-               // if image has coalesced symbols, then these need to be rebound, unless this is the only image with weak symbols
-               if ( this->needsCoalescing() && (fgCountOfImagesWithWeakExports > 1) ) {
-                       this->doBindExternalRelocations(context, true);
-                       this->doBindIndirectSymbolPointers(context, kLazyAndNonLazy, true);
-               }
-               // skip binding because prebound and prebinding not disabled
-               return;
-       }
+       // mach-o has -init and static initializers
+       doImageInit(context);
+       doModInitFunctions(context);

        
        

-       // values bound by name are stored two different ways in mach-o
-       switch (bindness) {
-               case kNonLazyOnly:
-               case kLazyAndNonLazy:
-                       // external relocations are used for data initialized to external symbols
-                       this->doBindExternalRelocations(context, false);
-                       break;
-               case kLazyOnly:
-               case kLazyOnlyNoDependents:
-                       break;
-       }
-       // "indirect symbols" are used for code references to external symbols
-       this->doBindIndirectSymbolPointers(context, bindness, false);
+       CRSetCrashLogMessage2(NULL);
+       
+       return (fHasDashInit || fHasInitializers);

 }
 
 }
 

+bool ImageLoaderMachO::needsInitialization()
+{
+       return ( fHasDashInit || fHasInitializers );
+}

 
 
 
 

-void ImageLoaderMachO::doImageInit(const LinkContext& context)
+bool ImageLoaderMachO::needsTermination()

 {
 {

-       if ( fDashInit != NULL ) {
-               Initializer func = (Initializer)(fDashInit->init_address + fSlide);
-               if ( context.verboseInit )
-                       fprintf(stderr, "dyld: calling -init function 0x%p in %s\n", func, this->getPath());
-               func(context.argc, context.argv, context.envp, context.apple);
-       }
+       return fHasTerminators;

 }
 
 }
 

-void ImageLoaderMachO::doModInitFunctions(const LinkContext& context)
+
+void ImageLoaderMachO::doTermination(const LinkContext& context)

 {
 {

-       if ( fModInitSection != NULL ) {
-               Initializer* inits = (Initializer*)(fModInitSection->addr + fSlide);
-               const uint32_t count = fModInitSection->size / sizeof(uintptr_t);
-               for (uint32_t i=0; i < count; ++i) {
-                       Initializer func = inits[i];
-                       if ( context.verboseInit )
-                               fprintf(stderr, "dyld: calling initializer function %p in %s\n", func, this->getPath());
-                       func(context.argc, context.argv, context.envp, context.apple);
+       if ( fHasTerminators ) {
+               const uint32_t cmd_count = ((macho_header*)fMachOData)->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_MOD_TERM_FUNC_POINTERS ) {
+                                               // <rdar://problem/23929217> Ensure section is within segment
+                                               if ( (sect->addr < seg->vmaddr) || (sect->addr+sect->size > seg->vmaddr+seg->vmsize) || (sect->addr+sect->size < sect->addr) )
+                                                       dyld::throwf("DOF section has malformed address range for %s\n", this->getPath());
+                                               Terminator* terms = (Terminator*)(sect->addr + fSlide);
+                                               const size_t count = sect->size / sizeof(uintptr_t);
+                                               for (size_t j=count; j > 0; --j) {
+                                                       Terminator func = terms[j-1];
+#if __has_feature(ptrauth_calls)
+                                                       func = (Terminator)__builtin_ptrauth_sign_unauthenticated((void*)func, ptrauth_key_asia, 0);
+#endif
+                                                       // <rdar://problem/8543820&9228031> verify terminators are in image
+                                                       if ( ! this->containsAddress(stripPointer((void*)func)) ) {
+                                                               dyld::throwf("termination function %p not in mapped image for %s\n", func, this->getPath());
+                                                       }
+                                                       if ( context.verboseInit )
+                                                               dyld::log("dyld: calling termination function %p in %s\n", func, this->getPath());
+                                                       func();
+                                               }
+                                       }
+                               }
+                       }
+                       cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

                }
        }
 }
 
 
                }
        }
 }
 
 

-void ImageLoaderMachO::doInitialization(const LinkContext& context)
+void ImageLoaderMachO::printStatisticsDetails(unsigned int imageCount, const InitializerTimingList& timingInfo)

 {
 {

-       // mach-o has -init and static initializers
-       doImageInit(context);
-       doModInitFunctions(context);
+       ImageLoader::printStatisticsDetails(imageCount, timingInfo);
+       dyld::log("total symbol trie searches:    %d\n", fgSymbolTrieSearchs);
+       dyld::log("total symbol table binary searches:    %d\n", fgSymbolTableBinarySearchs);
+       dyld::log("total images defining weak symbols:  %u\n", fgImagesHasWeakDefinitions);
+       dyld::log("total images using weak symbols:  %u\n", fgImagesRequiringCoalescing);

 }
 
 }
 

-bool ImageLoaderMachO::needsInitialization()
+
+intptr_t ImageLoaderMachO::assignSegmentAddresses(const LinkContext& context)

 {
 {

-       return ( (fDashInit != NULL) || (fModInitSection != NULL) );
+       // preflight and calculate slide if needed
+       const bool inPIE = (fgNextPIEDylibAddress != 0);
+       intptr_t slide = 0;
+       if ( this->segmentsCanSlide() && this->segmentsMustSlideTogether() ) {
+               bool needsToSlide = false;
+               bool imageHasPreferredLoadAddress = segHasPreferredLoadAddress(0);
+               uintptr_t lowAddr = (unsigned long)(-1);
+               uintptr_t highAddr = 0;
+               for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+                       const uintptr_t segLow = segPreferredLoadAddress(i);
+                       const uintptr_t segHigh = dyld_page_round(segLow + segSize(i));
+                       if ( segLow < highAddr ) {
+                               if ( dyld_page_size > 4096 )
+                                       dyld::throwf("can't map segments into 16KB pages");
+                               else
+                                       dyld::throwf("overlapping segments");
+                       }
+                       if ( segLow < lowAddr )
+                               lowAddr = segLow;
+                       if ( segHigh > highAddr )
+                               highAddr = segHigh;
+                               
+                       if ( needsToSlide || !imageHasPreferredLoadAddress || inPIE || !reserveAddressRange(segPreferredLoadAddress(i), segSize(i)) )
+                               needsToSlide = true;
+               }
+               if ( needsToSlide ) {
+                       // find a chunk of address space to hold all segments
+                       uintptr_t addr = reserveAnAddressRange(highAddr-lowAddr, context);
+                       slide = addr - lowAddr;
+               }
+       } 
+       else if ( ! this->segmentsCanSlide() ) {
+               for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+                       if ( (strcmp(segName(i), "__PAGEZERO") == 0) && (segFileSize(i) == 0) && (segPreferredLoadAddress(i) == 0) )
+                               continue;
+                       if ( !reserveAddressRange(segPreferredLoadAddress(i), segSize(i)) )
+                               dyld::throwf("can't map unslidable segment %s to 0x%lX with size 0x%lX", segName(i), segPreferredLoadAddress(i), segSize(i));
+               }
+       }
+       else {
+               throw "mach-o does not support independently sliding segments";
+       }
+       return slide;

 }
 
 
 }
 
 

-bool ImageLoaderMachO::needsTermination()
+uintptr_t ImageLoaderMachO::reserveAnAddressRange(size_t length, const ImageLoader::LinkContext& context)

 {
 {

-       return ( fModTermSection != NULL );
+       vm_address_t addr = 0;
+       vm_size_t size = length;
+       // in PIE programs, load initial dylibs after main executable so they don't have fixed addresses either
+       if ( fgNextPIEDylibAddress != 0 ) {
+                // add small (0-3 pages) random padding between dylibs
+               addr = fgNextPIEDylibAddress + (__stack_chk_guard/fgNextPIEDylibAddress & (sizeof(long)-1))*dyld_page_size;
+               //dyld::log("padding 0x%08llX, guard=0x%08llX\n", (long long)(addr - fgNextPIEDylibAddress), (long long)(__stack_chk_guard));
+               kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
+               if ( r == KERN_SUCCESS ) {
+                       fgNextPIEDylibAddress = addr + size;
+                       return addr;
+               }
+               fgNextPIEDylibAddress = 0;
+       }
+       kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_DYLIB));
+       if ( r != KERN_SUCCESS ) 
+               throw "out of address space";
+       
+       return addr;

 }
 
 }
 

-bool ImageLoaderMachO::hasImageNotification()
+bool ImageLoaderMachO::reserveAddressRange(uintptr_t start, size_t length)

 {
 {

-       return ( fImageNotifySection != NULL );
+       vm_address_t addr = start;
+       vm_size_t size = length;
+       kern_return_t r = vm_alloc(&addr, size, VM_FLAGS_FIXED | VM_MAKE_TAG(VM_MEMORY_DYLIB));
+       if ( r != KERN_SUCCESS ) 
+               return false;
+       return true;

 }
 
 
 }
 
 

-void ImageLoaderMachO::doTermination(const LinkContext& context)
-{
-       if ( fModTermSection != NULL ) {
-               Terminator* terms = (Terminator*)(fModTermSection->addr + fSlide);
-               const uint32_t count = fModTermSection->size / sizeof(uintptr_t);
-               for (uint32_t i=count; i > 0; --i) {
-                       Terminator func = terms[i-1];
-                       if ( context.verboseInit )
-                               fprintf(stderr, "dyld: calling terminaton function %p in %s\n", func, this->getPath());
-                       func();
-               }
-       }
-}

 
 

-void ImageLoaderMachO::doNotification(enum dyld_image_mode mode, uint32_t infoCount, const struct dyld_image_info info[])
+void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)

 {
 {

-       if ( fImageNotifySection != NULL ) {
-               dyld_image_notifier* notes = (dyld_image_notifier*)(fImageNotifySection->addr + fSlide);
-               const uint32_t count = fImageNotifySection->size / sizeof(uintptr_t);
-               for (uint32_t i=count; i > 0; --i) {
-                       dyld_image_notifier func = notes[i-1];
-                       func(mode, infoCount, info);
+       // find address range for image
+       intptr_t slide = this->assignSegmentAddresses(context);
+       if ( context.verboseMapping ) {
+               if ( offsetInFat != 0 )
+                       dyld::log("dyld: Mapping %s (slice offset=%llu)\n", this->getPath(), (unsigned long long)offsetInFat);
+               else
+                       dyld::log("dyld: Mapping %s\n", this->getPath());
+       }
+       // map in all segments
+       for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+               vm_offset_t fileOffset = (vm_offset_t)(segFileOffset(i) + offsetInFat);
+               vm_size_t size = segFileSize(i);
+               uintptr_t requestedLoadAddress = segPreferredLoadAddress(i) + slide;
+               int protection = 0;
+               if ( !segUnaccessible(i) ) {
+                       if ( segExecutable(i) )
+                               protection   |= PROT_EXEC;
+                       if ( segReadable(i) )
+                               protection   |= PROT_READ;
+                       if ( segWriteable(i) ) {
+                               protection   |= PROT_WRITE;
+                               // rdar://problem/22525618 force __LINKEDIT to always be mapped read-only
+                               if ( strcmp(segName(i), "__LINKEDIT") == 0 )
+                                       protection = PROT_READ;
+                       }
+               }
+       #if __i386__
+               // initially map __IMPORT segments R/W so dyld can update them
+               if ( segIsReadOnlyImport(i) )
+                       protection |= PROT_WRITE;
+       #endif
+               // wholly zero-fill segments have nothing to mmap() in
+               if ( size > 0 ) {
+                       if ( (fileOffset+size) > fileLen ) {
+                               dyld::throwf("truncated mach-o error: segment %s extends to %llu which is past end of file %llu", 
+                                                               segName(i), (uint64_t)(fileOffset+size), fileLen);
+                       }
+                       void* loadAddress = xmmap((void*)requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
+                       if ( loadAddress == ((void*)(-1)) ) {
+                               int mmapErr = errno;
+                               if ( mmapErr == EPERM ) {
+                                       if ( dyld::sandboxBlockedMmap(getPath()) )
+                                               dyld::throwf("file system sandbox blocked mmap() of '%s'", this->getPath());
+                                       else
+                                               dyld::throwf("code signing blocked mmap() of '%s'", this->getPath());
+                               }
+                               else
+                                       dyld::throwf("mmap() errno=%d at address=0x%08lX, size=0x%08lX segment=%s in Segment::map() mapping %s",
+                                               mmapErr, requestedLoadAddress, (uintptr_t)size, segName(i), getPath());
+                       }

                }
                }

+               // update stats
+               ++ImageLoader::fgTotalSegmentsMapped;
+               ImageLoader::fgTotalBytesMapped += size;
+               if ( context.verboseMapping )
+                       dyld::log("%18s at 0x%08lX->0x%08lX with permissions %c%c%c\n", segName(i), requestedLoadAddress, requestedLoadAddress+size-1,
+                               (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );

        }
        }

-}
-
-void ImageLoaderMachO::printStatistics(unsigned int imageCount)
-{
-       ImageLoader::printStatistics(imageCount);
-       fprintf(stderr, "total hinted binary tree searches:    %d\n", fgHintedBinaryTreeSearchs);
-       fprintf(stderr, "total unhinted binary tree searches:  %d\n", fgUnhintedBinaryTreeSearchs);
-       fprintf(stderr, "total images with weak exports:  %d\n", fgCountOfImagesWithWeakExports);
-       
-#if LINKEDIT_USAGE_DEBUG
-       fprintf(stderr, "linkedit pages accessed (%lu):\n", sLinkEditPageBuckets.size());
-#endif 
-}

 
 

-void ImageLoaderMachO::doPrebinding(const LinkContext& context, time_t timestamp, uint8_t* fileToPrebind)
-{
-       // update __DATA segment
-       this->applyPrebindingToDATA(fileToPrebind);
-       
-       // update load commands 
-       this->applyPrebindingToLoadCommands(context, fileToPrebind, timestamp);
-       
-       // update symbol table  
-       this->applyPrebindingToLinkEdit(context, fileToPrebind);
+       // update slide to reflect load location                        
+       this->setSlide(slide);

 }
 
 }
 

-void ImageLoaderMachO::applyPrebindingToDATA(uint8_t* fileToPrebind)
+void ImageLoaderMachO::mapSegments(const void* memoryImage, uint64_t imageLen, const LinkContext& context)

 {
 {

-       const unsigned int segmentCount = fSegments.size();
-       for(unsigned int i=0; i < segmentCount; ++i) {
-               SegmentMachO* seg = (SegmentMachO*)fSegments[i];
-               if ( seg->writeable() ) {
-                       memcpy(&fileToPrebind[seg->fFileOffset], (void*)seg->getActualLoadAddress(), seg->fFileSize);
-               }
+       // find address range for image
+       intptr_t slide = this->assignSegmentAddresses(context);
+       if ( context.verboseMapping )
+               dyld::log("dyld: Mapping memory %p\n", memoryImage);
+       // map in all segments
+       for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+               vm_address_t loadAddress = segPreferredLoadAddress(i) + slide;
+               vm_address_t srcAddr = (uintptr_t)memoryImage + segFileOffset(i);
+               vm_size_t size = segFileSize(i);
+               kern_return_t r = vm_copy(mach_task_self(), srcAddr, size, loadAddress);
+               if ( r != KERN_SUCCESS ) 
+                       throw "can't map segment";
+               if ( context.verboseMapping )
+                       dyld::log("%18s at 0x%08lX->0x%08lX\n", segName(i), (uintptr_t)loadAddress, (uintptr_t)loadAddress+size-1);
+       }
+       // update slide to reflect load location                        
+       this->setSlide(slide);
+       // set R/W permissions on all segments at slide location
+       for(unsigned int i=0, e=segmentCount(); i < e; ++i) {
+               segProtect(i, context);         
+       }
+}
+
+
+void ImageLoaderMachO::segProtect(unsigned int segIndex, const ImageLoader::LinkContext& context)
+{
+       vm_prot_t protection = 0;
+       if ( !segUnaccessible(segIndex) ) {
+               if ( segExecutable(segIndex) )
+                       protection   |= PROT_EXEC;
+               if ( segReadable(segIndex) )
+                       protection   |= PROT_READ;
+               if ( segWriteable(segIndex) )
+                       protection   |= PROT_WRITE;
+       }
+       vm_address_t addr = segActualLoadAddress(segIndex);
+       vm_size_t size = segSize(segIndex);
+       const bool setCurrentPermissions = false;
+       kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
+       if ( r != KERN_SUCCESS ) {
+        dyld::throwf("vm_protect(0x%08llX, 0x%08llX, false, 0x%02X) failed, result=%d for segment %s in %s",
+            (long long)addr, (long long)size, protection, r, segName(segIndex), this->getPath());
+    }
+       if ( context.verboseMapping ) {
+               dyld::log("%18s at 0x%08lX->0x%08lX altered permissions to %c%c%c\n", segName(segIndex), (uintptr_t)addr, (uintptr_t)addr+size-1,
+                       (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
+       }
+}      
+
+#if TEXT_RELOC_SUPPORT
+void ImageLoaderMachO::segMakeWritable(unsigned int segIndex, const ImageLoader::LinkContext& context)
+{
+       vm_address_t addr = segActualLoadAddress(segIndex);
+       vm_size_t size = segSize(segIndex);
+       const bool setCurrentPermissions = false;
+       vm_prot_t protection = VM_PROT_WRITE | VM_PROT_READ | VM_PROT_COPY;
+       if ( segExecutable(segIndex) && !segHasRebaseFixUps(segIndex) )
+               protection |= VM_PROT_EXECUTE;
+       kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
+       if ( r != KERN_SUCCESS ) {
+        dyld::throwf("vm_protect(0x%08llX, 0x%08llX, false, 0x%02X) failed, result=%d for segment %s in %s",
+            (long long)addr, (long long)size, protection, r, segName(segIndex), this->getPath());
+    }
+       if ( context.verboseMapping ) {
+               dyld::log("%18s at 0x%08lX->0x%08lX altered permissions to %c%c%c\n", segName(segIndex), (uintptr_t)addr, (uintptr_t)addr+size-1,
+                       (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );

        }
 }
        }
 }

+#endif

 
 

-void ImageLoaderMachO::applyPrebindingToLoadCommands(const LinkContext& context, uint8_t* fileToPrebind, time_t timestamp)
+const char* ImageLoaderMachO::findClosestSymbol(const mach_header* mh, const void* addr, const void** closestAddr)

 {
 {

-       macho_header* mh = (macho_header*)fileToPrebind;
+       // called by dladdr()
+       // only works with compressed LINKEDIT if classic symbol table is also present
+       const dysymtab_command* dynSymbolTable = NULL;
+       const symtab_command* symtab = NULL;
+       const macho_segment_command* seg;
+       const uint8_t* unslidLinkEditBase = NULL;
+       bool linkEditBaseFound = false;
+       intptr_t slide = 0;

        const uint32_t cmd_count = mh->ncmds;
        const uint32_t cmd_count = mh->ncmds;

-       const struct load_command* const cmds = (struct load_command*)&fileToPrebind[sizeof(macho_header)];
-       const struct load_command* cmd = cmds;
+       const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
+       const load_command* cmd = cmds;

        for (uint32_t i = 0; i < cmd_count; ++i) {
                switch (cmd->cmd) {
        for (uint32_t i = 0; i < cmd_count; ++i) {
                switch (cmd->cmd) {

-                       case LC_LOAD_DYLIB:
-                       case LC_LOAD_WEAK_DYLIB:
-                               {
-                                       // update each dylib load command with the timestamp of the target dylib
-                                       struct dylib_command* dylib  = (struct dylib_command*)cmd;
-                                       const char* name = (char*)cmd + dylib->dylib.name.offset;
-                                       for (const DependentLibrary* dl=fLibraries; dl < &fLibraries[fLibrariesCount]; dl++) {
-                                               if (strcmp(dl->name, name) == 0 ) {
-                                                       // found matching DependentLibrary for this load command
-                                                       ImageLoaderMachO* targetImage = (ImageLoaderMachO*)(dl->image); // !!! assume only mach-o images are prebound
-                                                       if ( ! targetImage->isPrebindable() )
-                                                               throw "dependent dylib is not prebound";
-                                                       // if the target is currently being re-prebound then its timestamp will be the same as this one
-                                                       if ( ! targetImage->usablePrebinding(context) ) {
-                                                               dylib->dylib.timestamp = timestamp;
-                                                       }
-                                                       else {
-                                                               // otherwise dependent library is already correctly prebound, so use its checksum
-                                                               dylib->dylib.timestamp = targetImage->doGetLibraryInfo().checksum;
-                                                       }
-                                                       break;
-                                               }
-                                       }
-                               }
-                               break;
-                       case LC_ID_DYLIB:
-                               {
-                                       // update the ID of this library with the new timestamp
-                                       struct dylib_command* dylib  = (struct dylib_command*)cmd;
-                                       dylib->dylib.timestamp = timestamp;
-                               }
-                               break;

                        case LC_SEGMENT_COMMAND:
                        case LC_SEGMENT_COMMAND:

-                               // if dylib was rebased, update segment commands
-                               if ( fSlide != 0 ) {
-                                       struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
-                                       seg->vmaddr += fSlide;
-                                       struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
-                                       struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
-                                       for (struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
-                                               sect->addr += fSlide;
-                                       }
-                               }
-                               break;
-                       case LC_ROUTINES_COMMAND:
-                               // if dylib was rebased, update -init command
-                               if ( fSlide != 0 ) {
-                                       struct macho_routines_command* routines = (struct macho_routines_command*)cmd;
-                                       routines->init_address += fSlide;
+                               seg = (macho_segment_command*)cmd;
+                               if ( strcmp(seg->segname, "__LINKEDIT") == 0 ) {
+                                       unslidLinkEditBase = (uint8_t*)(seg->vmaddr - seg->fileoff);
+                                       linkEditBaseFound = true;

                                }
                                }

+                               else if ( strcmp(seg->segname, "__TEXT") == 0 ) {
+                                       slide = (uintptr_t)mh - seg->vmaddr;
+                }

                                break;
                                break;

-               }
-               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
-       }       
-}
-
-void ImageLoaderMachO::applyPrebindingToLinkEdit(const LinkContext& context, uint8_t* fileToPrebind)
-{
-       // In prebound images, the n_value of the symbol table entry for is the prebound address
-       // This is needed when prebinding can't be used, to back solve for any possible addend in non-lazy pointers
-       const char* stringPool = NULL;
-       struct macho_nlist* symbolTable = NULL;
-       const struct dysymtab_command* dysymtab = NULL;
-       
-       // get symbol table info
-       macho_header* mh = (macho_header*)fileToPrebind;
-       const uint32_t cmd_count = mh->ncmds;
-       const struct load_command* const cmds = (struct load_command*)&fileToPrebind[sizeof(macho_header)];
-       const struct load_command* cmd = cmds;
-       for (uint32_t i = 0; i < cmd_count; ++i) {
-               switch (cmd->cmd) {

                        case LC_SYMTAB:
                        case LC_SYMTAB:

-                               {
-                                       const struct symtab_command* symtab = (struct symtab_command*)cmd;
-                                       stringPool = (const char*)&fileToPrebind[symtab->stroff];
-                                       symbolTable = (struct macho_nlist*)(&fileToPrebind[symtab->symoff]);
-                               }
+                               symtab = (symtab_command*)cmd;

                                break;
                        case LC_DYSYMTAB:
                                break;
                        case LC_DYSYMTAB:

-                               dysymtab = (struct dysymtab_command*)cmd;
+                               dynSymbolTable = (dysymtab_command*)cmd;

                                break;
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
                                break;
                }
                cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

-       }       
-
-       // walk all imports and re-resolve their n_value (needed incase prebinding is invalid)
-       struct macho_nlist* lastImport = &symbolTable[dysymtab->iundefsym+dysymtab->nundefsym];
-       for (struct macho_nlist* entry = &symbolTable[dysymtab->iundefsym]; entry < lastImport; ++entry) {
-               ImageLoader* dummy;
-               entry->n_value = this->resolveUndefined(context, entry, this->usesTwoLevelNameSpace(), &dummy);
-       }
-       
-       // walk all exports and slide their n_value
-       struct macho_nlist* lastExport = &symbolTable[dysymtab->iextdefsym+dysymtab->nextdefsym];
-       for (struct macho_nlist* entry = &symbolTable[dysymtab->iextdefsym]; entry < lastExport; ++entry) {
-               if ( (entry->n_type & N_TYPE) == N_SECT )
-                       entry->n_value += fSlide;
-       }
-
-       // walk all local symbols and slide their n_value
-       struct macho_nlist* lastLocal = &symbolTable[dysymtab->ilocalsym+dysymtab->nlocalsym];
-       for (struct macho_nlist* entry = &symbolTable[dysymtab->ilocalsym]; entry < lastLocal; ++entry) {
-               if ( entry->n_sect != NO_SECT )
-                       entry->n_value += fSlide;

        }
        }

-       
-       // walk all local relocations and reset every PPC_RELOC_PB_LA_PTR r_value
-       relocation_info* const relocsStart = (struct relocation_info*)(&fileToPrebind[dysymtab->locreloff]);
-       relocation_info* const relocsEnd = &relocsStart[dysymtab->nlocrel];
-       for (relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
-               if ( (reloc->r_address & R_SCATTERED) != 0 ) {
-                       struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
-                       if (sreloc->r_length == RELOC_SIZE) {
-                               switch(sreloc->r_type) {
-               #if __ppc__ || __ppc64__
-                                       case PPC_RELOC_PB_LA_PTR:
-               #elif __i386__
-                                       case GENERIC_RELOC_PB_LA_PTR:
-               #else
-                       #error unknown architecture
-               #endif
-                                               sreloc->r_value += fSlide;
-                                               break;
-                               }
+       // no symbol table => no lookup by address
+       if ( (symtab == NULL) || (dynSymbolTable == NULL) || !linkEditBaseFound )
+               return NULL;
+
+       const uint8_t* linkEditBase = unslidLinkEditBase + slide;
+       const char* symbolTableStrings = (const char*)&linkEditBase[symtab->stroff];
+       const macho_nlist* symbolTable = (macho_nlist*)(&linkEditBase[symtab->symoff]);
+
+       uintptr_t targetAddress = (uintptr_t)addr - slide;
+       const struct macho_nlist* bestSymbol = NULL;
+       // first walk all global symbols
+       const struct macho_nlist* const globalsStart = &symbolTable[dynSymbolTable->iextdefsym];
+       const struct macho_nlist* const globalsEnd= &globalsStart[dynSymbolTable->nextdefsym];
+       for (const struct macho_nlist* s = globalsStart; s < globalsEnd; ++s) {
+               if ( (s->n_type & N_TYPE) == N_SECT ) {
+                       if ( bestSymbol == NULL ) {
+                               if ( s->n_value <= targetAddress )
+                                       bestSymbol = s;
+                       }
+                       else if ( (s->n_value <= targetAddress) && (bestSymbol->n_value < s->n_value) ) {
+                               bestSymbol = s;

                        }
                }
        }
                        }
                }
        }

-       
-       // if multi-module, fix up objc_addr (10.4 and later runtime does not use this, but we want to keep file checksum consistent)
-       if ( dysymtab->nmodtab != 0 ) {
-               dylib_module* const modulesStart = (struct dylib_module*)(&fileToPrebind[dysymtab->modtaboff]);
-               dylib_module* const modulesEnd = &modulesStart[dysymtab->nmodtab];
-               for (dylib_module* module=modulesStart; module < modulesEnd; ++module) {
-                       if ( module->objc_module_info_size != 0 ) {
-                               module->objc_module_info_addr += fSlide;
+       // next walk all local symbols
+       const struct macho_nlist* const localsStart = &symbolTable[dynSymbolTable->ilocalsym];
+       const struct macho_nlist* const localsEnd= &localsStart[dynSymbolTable->nlocalsym];
+       for (const struct macho_nlist* s = localsStart; s < localsEnd; ++s) {
+               if ( ((s->n_type & N_TYPE) == N_SECT) && ((s->n_type & N_STAB) == 0) ) {
+                       if ( bestSymbol == NULL ) {
+                               if ( s->n_value <= targetAddress )
+                                       bestSymbol = s;
+                       }
+                       else if ( (s->n_value <= targetAddress) && (bestSymbol->n_value < s->n_value) ) {
+                               bestSymbol = s;

                        }
                }
        }
                        }
                }
        }

-}
-
-// file on disk has been reprebound, but we are still mapped to old file
-void ImageLoaderMachO::prebindUnmap(const LinkContext& context)
-{
-       // this removes all mappings to the old file, so the kernel will unlink (delete) it.
-       //  We need to leave the load commands and __LINKEDIT in place
-       for (std::vector<class Segment*>::iterator it=fSegments.begin(); it != fSegments.end(); ++it) {
-               void* segmentAddress = (void*)((*it)->getActualLoadAddress());
-               uintptr_t segmentSize = (*it)->getSize();
-               //fprintf(stderr, "unmapping segment %s at %p for %s\n", (*it)->getName(), segmentAddress, this->getPath());
-               // save load commands at beginning of __TEXT segment
-               if ( segmentAddress == fMachOData ) {
-                       // typically load commands are one or two pages in size, so ok to alloc on stack
-                       uint32_t loadCmdSize = sizeof(macho_header) + ((macho_header*)fMachOData)->sizeofcmds;
-                       uint32_t loadCmdPages = (loadCmdSize+4095) & (-4096);
-                       uint8_t loadcommands[loadCmdPages];
-                       memcpy(loadcommands, fMachOData, loadCmdPages);
-                       // unmap whole __TEXT segment
-                       munmap((void*)(fMachOData), segmentSize);
-                       // allocate and copy back mach_header and load commands
-                       vm_address_t addr = (vm_address_t)fMachOData;
-                       int r2 = vm_allocate(mach_task_self(), &addr, loadCmdPages, false /*at this address*/);
-                       if ( r2 != 0 )
-                               fprintf(stderr, "prebindUnmap() vm_allocate for __TEXT %d failed\n", loadCmdPages);
-                       memcpy((void*)fMachOData, loadcommands, loadCmdPages);
-                       //fprintf(stderr, "copying back load commands to %p size=%u for %s\n", segmentAddress, loadCmdPages, this->getPath());
-               }
-               else if ( strcmp((*it)->getName(), "__LINKEDIT") == 0 ) {
-                       uint32_t linkEditSize = segmentSize;
-                       uint32_t linkEditPages = (linkEditSize+4095) & (-4096);
-                       void* linkEditTmp = malloc(linkEditPages);
-                       memcpy(linkEditTmp, segmentAddress, linkEditPages);
-                       // unmap whole __LINKEDIT segment
-                       munmap(segmentAddress, segmentSize);
-                       vm_address_t addr = (vm_address_t)segmentAddress;
-                       int r2 = vm_allocate(mach_task_self(), &addr, linkEditPages, false /*at this address*/);
-                       if ( r2 != 0 )
-                               fprintf(stderr, "prebindUnmap() vm_allocate for __LINKEDIT %d failed\n", linkEditPages);
-                       memcpy(segmentAddress, linkEditTmp, linkEditPages);
-                       //fprintf(stderr, "copying back __LINKEDIT to %p size=%u for %s\n", segmentAddress, linkEditPages, this->getPath());
-                       free(linkEditTmp);
-               }
-               else {
-                       // unmap any other segment
-                       munmap((void*)(segmentAddress), (*it)->getSize());
-               }
+       if ( bestSymbol != NULL ) {
+#if __arm__
+               if (bestSymbol->n_desc & N_ARM_THUMB_DEF)
+                       *closestAddr = (void*)((bestSymbol->n_value | 1) + slide);
+               else
+                       *closestAddr = (void*)(bestSymbol->n_value + slide);
+#else
+               *closestAddr = (void*)(bestSymbol->n_value + slide);
+#endif
+               return &symbolTableStrings[bestSymbol->n_un.n_strx];

        }
        }

+       return NULL;

 }
 
 }
 

-
-
-SegmentMachO::SegmentMachO(const struct macho_segment_command* cmd, ImageLoaderMachO* image, const uint8_t* fileData)
- : fImage(image), fSize(cmd->vmsize), fFileSize(cmd->filesize), fFileOffset(cmd->fileoff), fPreferredLoadAddress(cmd->vmaddr), 
-       fVMProtection(cmd->initprot), fHasFixUps(false), fUnMapOnDestruction(false)
-{
-       strncpy(fName, cmd->segname, 16);
-       fName[16] = '\0';
-       // scan sections for fix-up bit
-       const struct macho_section* const sectionsStart = (struct macho_section*)((char*)cmd + sizeof(struct macho_segment_command));
-       const struct macho_section* const sectionsEnd = &sectionsStart[cmd->nsects];
-       for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
-               if ( (sect->flags & (S_ATTR_EXT_RELOC | S_ATTR_LOC_RELOC)) != 0 )
-                       fHasFixUps = true;
-       }
+bool ImageLoaderMachO::getLazyBindingInfo(uint32_t& lazyBindingInfoOffset, const uint8_t* lazyInfoStart, const uint8_t* lazyInfoEnd,
+                                                                                                       uint8_t* segIndex, uintptr_t* segOffset, int* ordinal, const char** symbolName, bool* doneAfterBind)
+{
+       if ( lazyBindingInfoOffset > (lazyInfoEnd-lazyInfoStart) )
+               return false;
+       uint8_t type = BIND_TYPE_POINTER;
+       uint8_t symboFlags = 0;
+       bool done = false;
+       const uint8_t* p = &lazyInfoStart[lazyBindingInfoOffset];
+       while ( !done && (p < lazyInfoEnd) ) {
+               uint8_t immediate = *p & BIND_IMMEDIATE_MASK;
+               uint8_t opcode = *p & BIND_OPCODE_MASK;
+               ++p;
+               switch (opcode) {
+                       case BIND_OPCODE_DONE:
+                               *doneAfterBind = false;
+                               return true;
+                               break;
+                       case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
+                               *ordinal = immediate;
+                               break;
+                       case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
+                               *ordinal = (int)read_uleb128(p, lazyInfoEnd);
+                               break;
+                       case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
+                               // the special ordinals are negative numbers
+                               if ( immediate == 0 )
+                                       *ordinal = 0;
+                               else {
+                                       int8_t signExtended = BIND_OPCODE_MASK | immediate;
+                                       *ordinal = signExtended;
+                               }
+                               break;
+                       case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
+                               *symbolName = (char*)p;
+                               symboFlags = immediate;
+                               while (*p != '\0')
+                                       ++p;
+                               ++p;
+                               break;
+                       case BIND_OPCODE_SET_TYPE_IMM:
+                               type = immediate;
+                               break;
+                       case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
+                               *segIndex  = immediate;
+                               *segOffset = read_uleb128(p, lazyInfoEnd);
+                               break;
+                       case BIND_OPCODE_DO_BIND:
+                               *doneAfterBind = ((*p & BIND_OPCODE_MASK) == BIND_OPCODE_DONE);
+                               lazyBindingInfoOffset += p - &lazyInfoStart[lazyBindingInfoOffset];
+                               return true;
+                               break;
+                       case BIND_OPCODE_SET_ADDEND_SLEB:
+                       case BIND_OPCODE_ADD_ADDR_ULEB:
+                       case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
+                       case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
+                       case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
+                       default:
+                               return false;
+               }
+       }       
+       return false;

 }
 
 }
 

-SegmentMachO::~SegmentMachO()
+const dyld_info_command* ImageLoaderMachO::findDyldInfoLoadCommand(const mach_header* mh)

 {
 {

-       if ( fUnMapOnDestruction ) {
-               //fprintf(stderr, "unmapping segment %s at 0x%08lX\n", getName(), getActualLoadAddress());
-               munmap((void*)(this->getActualLoadAddress()), this->getSize());
+       const uint32_t cmd_count = mh->ncmds;
+       const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
+       const load_command* cmd = cmds;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               switch (cmd->cmd) {
+                       case LC_DYLD_INFO:
+                       case LC_DYLD_INFO_ONLY:
+                               return (dyld_info_command*)cmd;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

+       return NULL;

 }
 
 }
 

-const ImageLoader* SegmentMachO::getImage()
-{
-       return fImage;
-}
-
-const char* SegmentMachO::getName()
-{
-       return fName;
-}
-
-uintptr_t SegmentMachO::getSize()
-{
-       return fSize;
-}
-
-uintptr_t SegmentMachO::getFileSize()
-{
-       return fFileSize;
-}
-
-uintptr_t SegmentMachO::getFileOffset()
-{
-       return fFileOffset;
-}
-
-bool SegmentMachO::readable()
-{
-       return ( (fVMProtection & VM_PROT_READ) != 0);
-}
-
-bool SegmentMachO::writeable()
-{
-       return ((fVMProtection & VM_PROT_WRITE) != 0);
-}
-
-bool SegmentMachO::executable()
-{
-       return ((fVMProtection & VM_PROT_EXECUTE) != 0);
-}
-
-bool SegmentMachO::unaccessible()
-{
-       return (fVMProtection == 0);
-}
-
-bool SegmentMachO::hasFixUps()
-{
-       return fHasFixUps;
-}
-
-uintptr_t SegmentMachO::getActualLoadAddress()
-{
-       return fPreferredLoadAddress + fImage->fSlide;
-}
-
-uintptr_t SegmentMachO::getPreferredLoadAddress()
-{
-       return fPreferredLoadAddress;
-}
-
-bool SegmentMachO::hasPreferredLoadAddress()
-{
-       return (fPreferredLoadAddress != 0);
-}
-
-void SegmentMachO::setUnMapWhenDestructed(bool unmap)
-{
-       fUnMapOnDestruction = unmap;
-}

 
 

-static uint32_t *buildCRCTable(void)
+uintptr_t ImageLoaderMachO::segPreferredAddress(const mach_header* mh, unsigned segIndex)

 {
 {

-       uint32_t *table = new uint32_t[256];
-       uint32_t p = 0xedb88320UL;  // standard CRC-32 polynomial
-
-       for (unsigned int i = 0; i < 256; i++) {
-               uint32_t c = i;
-               for (unsigned int j = 0; j < 8; j++) {
-                       if ( c & 1 ) c = p ^ (c >> 1);
-                       else c = c >> 1;
+       const uint32_t cmd_count = mh->ncmds;
+       const load_command* const cmds = (load_command*)((char*)mh + sizeof(macho_header));
+       const load_command* cmd = cmds;
+       unsigned curSegIndex = 0;
+       for (uint32_t i = 0; i < cmd_count; ++i) {
+               if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
+                       if ( segIndex == curSegIndex ) {
+                               const macho_segment_command* segCmd = (macho_segment_command*)cmd;
+                               return segCmd->vmaddr;
+                       }
+                       ++curSegIndex;

                }
                }

-               table[i] = c;
-       }
-
-       return table;
-}
-
-uint32_t SegmentMachO::crc32()
-{
-       if ( !readable() ) return 0;
-
-       static uint32_t *crcTable = NULL;
-       if ( !crcTable ) crcTable = buildCRCTable();
-       
-       uint32_t crc = ~(uint32_t)0;
-       uint8_t *p = (uint8_t *)getActualLoadAddress(); 
-       uint8_t *end = p + getSize();
-       while ( p < end ) {
-               crc = crcTable[(crc & 0xff) ^ (*p++)] ^ (crc >> 8);
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);

        }
        }

-       return crc ^ ~(uint32_t)0;
+       return 0;

 }
 
 
 
 }
 
 
 

-
+uintptr_t ImageLoaderMachO::imageBaseAddress() const {
+    //printf("imageBaseAddress: %s %d->%d\n", getPath(), 0, segmentCount());
+    for (unsigned int i = 0, e = segmentCount(); i != e; ++i) {
+        if ( (segFileOffset(i) == 0) && (segFileSize(i) != 0) )
+            return segPreferredLoadAddress(i);
+    }
+    return 0;
+}