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dyld-635.2.tar.gz
[apple/dyld.git] / src / ImageLoaderMachOCompressed.cpp
index 020ec51fcd87f62f20e1d9eb2f6bf68b4f24c07a..a908c915aa986625dd76c831cdb486cda99d452e 100644 (file)
 #include <sys/fcntl.h>
 #include <sys/stat.h> 
 #include <sys/param.h>
-#include <sys/sysctl.h>
 #include <mach/mach.h>
 #include <mach/thread_status.h>
 #include <mach-o/loader.h> 
 #include "ImageLoaderMachOCompressed.h"
 #include "mach-o/dyld_images.h"
+#include "Closure.h"
+#include "Array.h"
 
 #ifndef EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE
        #define EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE                       0x02
 #endif
 
+
+#ifndef BIND_OPCODE_THREADED
+#define BIND_OPCODE_THREADED    0xD0
+#endif
+
+#ifndef BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB
+#define BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB       0x00
+#endif
+
+#ifndef BIND_SUBOPCODE_THREADED_APPLY
+#define BIND_SUBOPCODE_THREADED_APPLY                                                          0x01
+#endif
+
+
+#ifndef BIND_SPECIAL_DYLIB_WEAK_LOOKUP
+#define BIND_SPECIAL_DYLIB_WEAK_LOOKUP                                                         -3
+#endif
+
+#ifndef CPU_SUBTYPE_ARM64_E
+       #define CPU_SUBTYPE_ARM64_E    2
+#endif
+
 // 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
        struct macho_routines_command   : public routines_command  {};  
 #endif
 
-#if __arm__ || __arm64__
-bool ImageLoaderMachOCompressed::sVmAccountingDisabled  = false;
-bool ImageLoaderMachOCompressed::sVmAccountingSuspended = false;
-#endif
-
 
 
 // create image for main executable
@@ -157,10 +175,6 @@ ImageLoaderMachOCompressed* ImageLoaderMachOCompressed::instantiateFromFile(cons
                // make sure path is stable before recording in dyld_all_image_infos
                image->setMapped(context);
 
-               // dylibs with thread local variables cannot be unloaded because there is no way to clean up all threads
-               if ( image->machHeader()->flags & MH_HAS_TLV_DESCRIPTORS )
-                       image->setNeverUnload();
-
                // pre-fetch content of __DATA and __LINKEDIT segment for faster launches
                // don't do this on prebound images or if prefetching is disabled
         if ( !context.preFetchDisabled && !image->isPrebindable()) {
@@ -493,7 +507,7 @@ void ImageLoaderMachOCompressed::rebase(const LinkContext& context, uintptr_t sl
                                        fgTotalRebaseFixups += count;
                                        break;
                                default:
-                                       dyld::throwf("bad rebase opcode %d", *p);
+                                       dyld::throwf("bad rebase opcode %d", *(p-1));
                        }
                }
        }
@@ -666,6 +680,95 @@ uintptr_t ImageLoaderMachOCompressed::resolveFlat(const LinkContext& context, co
 }
 
 
+#if USES_CHAINED_BINDS
+static void patchCacheUsesOf(const ImageLoader::LinkContext& context, const dyld3::closure::Image* overriddenImage,
+                                                        uint32_t cacheOffsetOfImpl, const char* symbolName, uintptr_t newImpl)
+{
+       uintptr_t cacheStart = (uintptr_t)context.dyldCache;
+       overriddenImage->forEachPatchableUseOfExport(cacheOffsetOfImpl, ^(dyld3::closure::Image::PatchableExport::PatchLocation patchLocation) {
+               uintptr_t* loc = (uintptr_t*)(cacheStart+patchLocation.cacheOffset);
+#if __has_feature(ptrauth_calls)
+               if ( patchLocation.authenticated ) {
+                        dyld3::MachOLoaded::ChainedFixupPointerOnDisk fixupInfo;
+                       fixupInfo.authRebase.auth      = true;
+                       fixupInfo.authRebase.addrDiv   = patchLocation.usesAddressDiversity;
+                       fixupInfo.authRebase.diversity = patchLocation.discriminator;
+                       fixupInfo.authRebase.key       = patchLocation.key;
+                       uintptr_t newValue = fixupInfo.signPointer(loc, newImpl + patchLocation.getAddend());
+                       if ( *loc != newValue ) {
+                               *loc = newValue;
+                               if ( context.verboseBind )
+                                       dyld::log("dyld: cache fixup: *%p = %p (JOP: diversity 0x%04X, addr-div=%d, key=%s) to %s\n",
+                                                       loc, (void*)newValue, patchLocation.discriminator, patchLocation.usesAddressDiversity, patchLocation.keyName(), symbolName);
+                       }
+                       return;
+               }
+#endif
+               uintptr_t newValue =newImpl + patchLocation.getAddend();
+               if ( *loc != newValue ) {
+                       *loc = newValue;
+                       if ( context.verboseBind )
+                               dyld::log("dyld: cache fixup: *%p = %p to %s\n", loc, (void*)newValue, symbolName);
+               }
+       });
+}
+#endif
+
+
+uintptr_t ImageLoaderMachOCompressed::resolveWeak(const LinkContext& context, const char* symbolName, bool weak_import,
+                                                                                                 bool runResolver, const ImageLoader** foundIn)
+{
+       const Symbol* sym;
+#if USES_CHAINED_BINDS
+       __block uintptr_t foundOutsideCache  = 0;
+       __block uintptr_t lastFoundInCache = 0;
+       CoalesceNotifier notifier = ^(const Symbol* implSym, const ImageLoader* implIn, const mach_header* implMh) {
+               //dyld::log("notifier: found %s in %p %s\n", symbolName, implMh, implIn->getPath());
+               // This block is only called in dyld2 mode when a non-cached image is search for which weak-def implementation to use
+               // As a side effect of that search we notice any implementations outside and inside the cache,
+               // and use that to trigger patching the cache to use the implementation outside the cache.
+               uintptr_t implAddr = implIn->getExportedSymbolAddress(implSym, context, nullptr, false, symbolName);
+               if ( ((dyld3::MachOLoaded*)implMh)->inDyldCache() ) {
+                       if ( foundOutsideCache != 0 ) {
+                               // have an implementation in cache and and earlier one not in the cache, patch cache to use earlier one
+                               lastFoundInCache = implAddr;
+                               uint32_t imageIndex;
+                               if ( context.dyldCache->findMachHeaderImageIndex(implMh, imageIndex) ) {
+                                       const dyld3::closure::Image* overriddenImage = context.dyldCache->cachedDylibsImageArray()->imageForNum(imageIndex+1);
+                                       uint32_t cacheOffsetOfImpl = (uint32_t)((uintptr_t)implAddr - (uintptr_t)context.dyldCache);
+                                       patchCacheUsesOf(context, overriddenImage, cacheOffsetOfImpl, symbolName, foundOutsideCache);
+                               }
+                       }
+               }
+               else {
+                       // record first non-cache implementation
+                       if ( foundOutsideCache == 0 )
+                               foundOutsideCache = implAddr;
+               }
+       };
+#else
+       CoalesceNotifier notifier = nullptr;
+#endif
+       if ( context.coalescedExportFinder(symbolName, &sym, foundIn, notifier) ) {
+               if ( *foundIn != this )
+                       context.addDynamicReference(this, const_cast<ImageLoader*>(*foundIn));
+               return (*foundIn)->getExportedSymbolAddress(sym, context, this, runResolver);
+       }
+       // if a bundle is loaded privately the above will not find its exports
+       if ( this->isBundle() && this->hasHiddenExports() ) {
+               // look in self for needed symbol
+               sym = this->findShallowExportedSymbol(symbolName, foundIn);
+               if ( sym != NULL )
+                       return (*foundIn)->getExportedSymbolAddress(sym, context, this, runResolver);
+       }
+       if ( weak_import ) {
+               // definition can't be found anywhere, ok because it is weak, just return 0
+               return 0;
+       }
+       throwSymbolNotFound(context, symbolName, this->getPath(), "", "weak");
+}
+
+
 uintptr_t ImageLoaderMachOCompressed::resolveTwolevel(const LinkContext& context, const char* symbolName, const ImageLoader* definedInImage,
                                                                                                          const ImageLoader* requestorImage, unsigned requestorOrdinalOfDef, bool weak_import, bool runResolver,
                                                                                                          const ImageLoader** foundIn)
@@ -722,6 +825,9 @@ uintptr_t ImageLoaderMachOCompressed::resolve(const LinkContext& context, const
        if ( context.bindFlat || (libraryOrdinal == BIND_SPECIAL_DYLIB_FLAT_LOOKUP) ) {
                symbolAddress = this->resolveFlat(context, symbolName, weak_import, runResolver, targetImage);
        }
+       else if ( libraryOrdinal == BIND_SPECIAL_DYLIB_WEAK_LOOKUP ) {
+               symbolAddress = this->resolveWeak(context, symbolName, false, runResolver, targetImage);
+       }
        else {
                if ( libraryOrdinal == BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE ) {
                        *targetImage = context.mainExecutable;
@@ -767,18 +873,24 @@ uintptr_t ImageLoaderMachOCompressed::resolve(const LinkContext& context, const
        return symbolAddress;
 }
 
-uintptr_t ImageLoaderMachOCompressed::bindAt(const LinkContext& context, uintptr_t addr, uint8_t type, const char* symbolName, 
-                                                               uint8_t symbolFlags, intptr_t addend, long libraryOrdinal, const char* msg,
-                                                               LastLookup* last, bool runResolver)
+uintptr_t ImageLoaderMachOCompressed::bindAt(const LinkContext& context, ImageLoaderMachOCompressed* image,
+                                                                                        uintptr_t addr, uint8_t type, const char* symbolName,
+                                                                                        uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                                                        ExtraBindData *extraBindData,
+                                                                                        const char* msg, LastLookup* last, bool runResolver)
 {
        const ImageLoader*      targetImage;
        uintptr_t                       symbolAddress;
        
        // resolve symbol
-       symbolAddress = this->resolve(context, symbolName, symbolFlags, libraryOrdinal, &targetImage, last, runResolver);
+    if (type == BIND_TYPE_THREADED_REBASE) {
+        symbolAddress = 0;
+        targetImage = nullptr;
+    } else
+        symbolAddress = image->resolve(context, symbolName, symbolFlags, libraryOrdinal, &targetImage, last, runResolver);
 
        // do actual update
-       return this->bindLocation(context, addr, symbolAddress, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, msg);
+       return image->bindLocation(context, image->imageBaseAddress(), addr, symbolAddress, type, symbolName, addend, image->getPath(), targetImage ? targetImage->getPath() : NULL, msg, extraBindData, image->fSlide);
 }
 
 
@@ -799,6 +911,21 @@ void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLa
        // note: flat-namespace binaries need to have imports rebound (even if correctly prebound)
        if ( this->usablePrebinding(context) ) {
                // don't need to bind
+               // except weak which may now be inline with the regular binds
+               if (this->participatesInCoalescing()) {
+                       // run through all binding opcodes
+                       eachBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                                               uintptr_t addr, uint8_t type, const char* symbolName,
+                                                               uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                               ExtraBindData *extraBindData,
+                                                               const char* msg, LastLookup* last, bool runResolver) {
+                               if ( libraryOrdinal != BIND_SPECIAL_DYLIB_WEAK_LOOKUP )
+                                       return (uintptr_t)0;
+                               return ImageLoaderMachOCompressed::bindAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                                 addend, libraryOrdinal, extraBindData,
+                                                                                                                 msg, last, runResolver);
+                       });
+               }
        }
        else {
                uint64_t t0 = mach_absolute_time();
@@ -808,9 +935,21 @@ void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLa
                if ( fTextSegmentBinds ) 
                        this->makeTextSegmentWritable(context, true);
        #endif
-       
+
+               uint32_t ignore;
+               bool bindingBecauseOfRoot = ( this->overridesCachedDylib(ignore) || this->inSharedCache() );
+               vmAccountingSetSuspended(context, bindingBecauseOfRoot);
+
                // run through all binding opcodes
-               eachBind(context, &ImageLoaderMachOCompressed::bindAt);
+               eachBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                                       uintptr_t addr, uint8_t type, const char* symbolName,
+                                                       uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                       ExtraBindData *extraBindData,
+                                                       const char* msg, LastLookup* last, bool runResolver) {
+                       return ImageLoaderMachOCompressed::bindAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                         addend, libraryOrdinal, extraBindData,
+                                                                                                         msg, last, runResolver);
+               });
                        
        #if TEXT_RELOC_SUPPORT
                // if there were __TEXT fixups, restore write protection
@@ -828,7 +967,7 @@ void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLa
         // the stub may have been altered to point to a shared lazy pointer.
                if ( fInSharedCache ) 
                        this->updateOptimizedLazyPointers(context);
-       
+
                // tell kernel we are done with chunks of LINKEDIT
                if ( !context.preFetchDisabled ) 
                        this->markFreeLINKEDIT(context);
@@ -836,6 +975,23 @@ void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLa
                uint64_t t1 = mach_absolute_time();
                ImageLoader::fgTotalRebindCacheTime += (t1-t0);
        }
+
+#if USES_CHAINED_BINDS
+       // See if this dylib overrides something in the dyld cache
+       uint32_t dyldCacheOverrideImageNum;
+       if ( context.dyldCache && overridesCachedDylib(dyldCacheOverrideImageNum) ) {
+               // need to patch all other places in cache that point to the overridden dylib, to point to this dylib instead
+               const dyld3::closure::Image* overriddenImage = context.dyldCache->cachedDylibsImageArray()->imageForNum(dyldCacheOverrideImageNum);
+               overriddenImage->forEachPatchableExport(^(uint32_t cacheOffsetOfImpl, const char* exportName) {
+                       uintptr_t newImpl = 0;
+                       const ImageLoader* foundIn;
+                       if ( const ImageLoader::Symbol* sym = this->findShallowExportedSymbol(exportName, &foundIn) ) {
+                               newImpl = foundIn->getExportedSymbolAddress(sym, context, this);
+                       }
+                       patchCacheUsesOf(context, overriddenImage, cacheOffsetOfImpl, exportName, newImpl);
+               });
+       }
+#endif
        
        // set up dyld entry points in image
        // do last so flat main executables will have __dyld or __program_vars set up
@@ -846,49 +1002,179 @@ void ImageLoaderMachOCompressed::doBind(const LinkContext& context, bool forceLa
 
 void ImageLoaderMachOCompressed::doBindJustLazies(const LinkContext& context)
 {
-       eachLazyBind(context, &ImageLoaderMachOCompressed::bindAt);
+       eachLazyBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                                       uintptr_t addr, uint8_t type, const char* symbolName,
+                                                       uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                       ExtraBindData *extraBindData,
+                                                       const char* msg, LastLookup* last, bool runResolver) {
+               return ImageLoaderMachOCompressed::bindAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                 addend, libraryOrdinal, extraBindData,
+                                                                                                 msg, last, runResolver);
+       });
 }
 
-#if __arm__ || __arm64__
-int ImageLoaderMachOCompressed::vmAccountingSetSuspended(bool suspend, const LinkContext& context)
+void ImageLoaderMachOCompressed::registerInterposing(const LinkContext& context)
 {
-    if ( context.verboseBind )
-        dyld::log("vm.footprint_suspend=%d\n", suspend);
-    int newValue = suspend ? 1 : 0;
-    int oldValue = 0;
-    size_t newlen = sizeof(newValue);
-    size_t oldlen = sizeof(oldValue);
-    return sysctlbyname("vm.footprint_suspend", &oldValue, &oldlen, &newValue, newlen);
+       // 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) {
+                       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 ( ((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());
+                                               __block uintptr_t sectionStart = sect->addr + fSlide;
+                                               __block uintptr_t sectionEnd = sectionStart + sect->size;
+                                               const size_t count = sect->size / sizeof(InterposeData);
+                                               InterposeData interposeArray[count];
+                                               // Note, we memcpy here as rebases may have already been applied.
+                                               memcpy(&interposeArray[0], (void*)sectionStart, sect->size);
+                                               __block InterposeData *interposeArrayStart = &interposeArray[0];
+                                               eachBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image, uintptr_t addr, uint8_t type,
+                                                                                       const char* symbolName, uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                                                       ExtraBindData *extraBindData,
+                                                                                       const char* msg, LastLookup* last, bool runResolver) {
+                                                       if (addr >= sectionStart && addr < sectionEnd) {
+                                                               if ( context.verboseInterposing ) {
+                                                                       dyld::log("dyld: interposing %s at 0x%lx in range 0x%lx..0x%lx\n",
+                                                                                         symbolName, addr, sectionStart, sectionEnd);
+                                                               }
+                                                               const ImageLoader*      targetImage;
+                                                               uintptr_t                       symbolAddress;
+
+                                                               // resolve symbol
+                                                               if (type == BIND_TYPE_THREADED_REBASE) {
+                                                                       symbolAddress = 0;
+                                                                       targetImage = nullptr;
+                                                               } else
+                                                                       symbolAddress = image->resolve(ctx, symbolName, symbolFlags, libraryOrdinal, &targetImage, last, runResolver);
+
+                                                               uintptr_t newValue = symbolAddress+addend;
+                                                               uintptr_t index = (addr - sectionStart) / sizeof(uintptr_t);
+                                                               switch (type) {
+                                                                       case BIND_TYPE_POINTER:
+                                                                               ((uintptr_t*)interposeArrayStart)[index] = newValue;
+                                                                               break;
+                                                                       case BIND_TYPE_TEXT_ABSOLUTE32:
+                                                                               // unreachable!
+                                                                               abort();
+                                                                       case BIND_TYPE_TEXT_PCREL32:
+                                                                               // unreachable!
+                                                                               abort();
+                                                                       case BIND_TYPE_THREADED_BIND:
+                                                                               ((uintptr_t*)interposeArrayStart)[index] = 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 = (*(uint64_t*)addr) & 0x0007F80000000000ULL;
+                                                                               uint64_t bottom43Bits = (*(uint64_t*)addr) & 0x000007FFFFFFFFFFULL;
+                                                                               uint64_t targetValue = ( top8Bits << 13 ) | (((intptr_t)(bottom43Bits << 21) >> 21) & 0x00FFFFFFFFFFFFFF);
+                                                                               newValue = (uintptr_t)(targetValue + fSlide);
+                                                                               ((uintptr_t*)interposeArrayStart)[index] = newValue;
+                                                                               break;
+                                                                       }
+                                                                       default:
+                                                                               dyld::throwf("bad bind type %d", type);
+                                                               }
+                                                       }
+                                                       return (uintptr_t)0;
+                                               });
+                                               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;
+                                                       if ( context.verboseInterposing ) {
+                                                               dyld::log("dyld: interposing index %d 0x%lx with 0x%lx\n",
+                                                                                 (unsigned)j, interposeArray[j].replacee, interposeArray[j].replacement);
+                                                       }
+                                                       // <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);
+                                                       }
+                                               }
+                                       }
+                               }
+                       }
+                               break;
+               }
+               cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+       }
 }
+
+bool ImageLoaderMachOCompressed::usesChainedFixups() const
+{
+#if __arm64e__
+       return ( machHeader()->cpusubtype == CPU_SUBTYPE_ARM64_E );
+#else
+       return false;
 #endif
+}
+
+struct ThreadedBindData {
+    ThreadedBindData(const char* symbolName, int64_t addend, long libraryOrdinal, uint8_t symbolFlags, uint8_t type)
+    : symbolName(symbolName), addend(addend), libraryOrdinal(libraryOrdinal), symbolFlags(symbolFlags), type(type) { }
+
+    std::tuple<const char*, int64_t, long, bool, uint8_t> pack() const {
+        return std::make_tuple(symbolName, addend, libraryOrdinal, symbolFlags, type);
+    }
+
+    const char* symbolName     = nullptr;
+    int64_t addend             = 0;
+    long libraryOrdinal        = 0;
+    uint8_t symbolFlags        = 0;
+    uint8_t type               = 0;
+};
 
 void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handler handler)
 {
-#if __arm__ || __arm64__
-    // <rdar://problem/29099600> dyld should tell the kernel when it is doing root fix-ups
-    if ( !sVmAccountingDisabled ) {
-        if ( fInSharedCache ) {
-            if ( !sVmAccountingSuspended ) {
-                int ret = vmAccountingSetSuspended(true, context);
-                if ( context.verboseBind && (ret != 0) )
-                    dyld::log("vm.footprint_suspend => %d, errno=%d\n", ret, errno);
-                if ( ret == 0 )
-                    sVmAccountingSuspended = true;
-                else
-                    sVmAccountingDisabled = true;
+    try {
+        const dysymtab_command* dynSymbolTable = NULL;
+        const macho_nlist* symbolTable = NULL;
+        const char* symbolTableStrings = NULL;
+        uint32_t maxStringOffset = 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_SYMTAB:
+                {
+                    const struct symtab_command* symtab = (struct symtab_command*)cmd;
+                    symbolTableStrings = (const char*)&fLinkEditBase[symtab->stroff];
+                    maxStringOffset = symtab->strsize;
+                    symbolTable = (macho_nlist*)(&fLinkEditBase[symtab->symoff]);
+                }
+                    break;
+                case LC_DYSYMTAB:
+                    dynSymbolTable = (struct dysymtab_command*)cmd;
+                    break;
             }
+            cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
         }
-        else if ( sVmAccountingSuspended ) {
-            int ret = vmAccountingSetSuspended(false, context);
-            if ( ret == 0 )
-                sVmAccountingSuspended = false;
-            else if ( errno == ENOENT )
-                sVmAccountingDisabled = true;
-        }
-    }
-#endif
 
-       try {
                uint8_t type = 0;
                int segmentIndex = -1;
                uintptr_t address = segActualLoadAddress(0);
@@ -901,7 +1187,11 @@ void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handl
                intptr_t addend = 0;
                uintptr_t count;
                uintptr_t skip;
-               uintptr_t segOffset;
+        uintptr_t segOffset = 0;
+
+               dyld3::OverflowSafeArray<ThreadedBindData> ordinalTable;
+        bool useThreadedRebaseBind = false;
+        ExtraBindData extraBindData;
                LastLookup last = { 0, 0, NULL, 0, NULL };
                const uint8_t* const start = fLinkEditBase + fDyldInfo->bind_off;
                const uint8_t* const end = &start[fDyldInfo->bind_size];
@@ -968,16 +1258,21 @@ void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handl
                                        address += read_uleb128(p, end);
                                        break;
                                case BIND_OPCODE_DO_BIND:
-                                       if ( (address < segmentStartAddress) || (address >= segmentEndAddress) )
-                                               throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-                                       if ( symbolName  == NULL )
-                                               dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM");
-                                       if ( segmentIndex == -1 )
-                                               dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB");
-                                       if ( !libraryOrdinalSet )
-                                               dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_DYLIB_ORDINAL*");
-                                       (this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
-                                       address += sizeof(intptr_t);
+                    if (!useThreadedRebaseBind) {
+                        if ( (address < segmentStartAddress) || (address >= segmentEndAddress) )
+                            throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
+                        if ( symbolName  == NULL )
+                            dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM");
+                        if ( segmentIndex == -1 )
+                            dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB");
+                        if ( !libraryOrdinalSet )
+                            dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_DYLIB_ORDINAL*");
+                        handler(context, this, address, type, symbolName, symboFlags, addend, libraryOrdinal,
+                                                               &extraBindData, "", &last, false);
+                        address += sizeof(intptr_t);
+                    } else {
+                        ordinalTable.push_back(ThreadedBindData(symbolName, addend, libraryOrdinal, symboFlags, type));
+                    }
                                        break;
                                case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
                                        if ( (address < segmentStartAddress) || (address >= segmentEndAddress) )
@@ -988,7 +1283,8 @@ void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handl
                                                dyld::throwf("BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB missing preceding BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB");
                                        if ( !libraryOrdinalSet )
                                                dyld::throwf("BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB missing preceding BIND_OPCODE_SET_DYLIB_ORDINAL*");
-                                       (this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
+                    handler(context, this, address, type, symbolName, symboFlags, addend, libraryOrdinal,
+                                     &extraBindData, "", &last, false);
                                        address += read_uleb128(p, end) + sizeof(intptr_t);
                                        break;
                                case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
@@ -1000,7 +1296,8 @@ void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handl
                                                dyld::throwf("BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED missing preceding BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB");
                                        if ( !libraryOrdinalSet )
                                                dyld::throwf("BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED missing preceding BIND_OPCODE_SET_DYLIB_ORDINAL*");
-                                       (this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
+                    handler(context, this, address, type, symbolName, symboFlags, addend, libraryOrdinal,
+                                     &extraBindData, "", &last, false);
                                        address += immediate*sizeof(intptr_t) + sizeof(intptr_t);
                                        break;
                                case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
@@ -1015,10 +1312,69 @@ void ImageLoaderMachOCompressed::eachBind(const LinkContext& context, bind_handl
                                        for (uint32_t i=0; i < count; ++i) {
                                                if ( (address < segmentStartAddress) || (address >= segmentEndAddress) )
                                                        throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
-                                               (this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "", &last, false);
+                        handler(context, this, address, type, symbolName, symboFlags, addend, libraryOrdinal,
+                                         &extraBindData, "", &last, false);
                                                address += skip + sizeof(intptr_t);
                                        }
-                                       break;
+                    break;
+                case BIND_OPCODE_THREADED:
+                    if (sizeof(intptr_t) != 8) {
+                        dyld::throwf("BIND_OPCODE_THREADED require 64-bit");
+                        return;
+                    }
+                    // Note the immediate is a sub opcode
+                    switch (immediate) {
+                        case BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB:
+                            count = read_uleb128(p, end);
+                            ordinalTable.clear();
+                            // FIXME: ld64 wrote the wrong value here and we need to offset by 1 for now.
+                            ordinalTable.reserve(count + 1);
+                            useThreadedRebaseBind = true;
+                            break;
+                        case BIND_SUBOPCODE_THREADED_APPLY: {
+                            uint64_t delta = 0;
+                            do {
+                                address = segmentStartAddress + segOffset;
+                                uint64_t value = *(uint64_t*)address;
+
+
+                                bool isRebase = (value & (1ULL << 62)) == 0;
+                                if (isRebase) {
+                                    {
+                                        // Call the bind handler which knows about our bind type being set to rebase
+                                        handler(context, this, address, BIND_TYPE_THREADED_REBASE, nullptr, 0, 0, 0,
+                                                         nullptr, "", &last, false);
+                                    }
+                                } else {
+                                    // the ordinal is bits [0..15]
+                                    uint16_t ordinal = value & 0xFFFF;
+                                    if (ordinal >= ordinalTable.count()) {
+                                        dyld::throwf("bind ordinal is out of range\n");
+                                        return;
+                                    }
+                                    std::tie(symbolName, addend, libraryOrdinal, symboFlags, type) = ordinalTable[ordinal].pack();
+                                    if ( (address < segmentStartAddress) || (address >= segmentEndAddress) )
+                                        throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
+                                    {
+                                        handler(context, this, address, BIND_TYPE_THREADED_BIND,
+                                                         symbolName, symboFlags, addend, libraryOrdinal,
+                                                         nullptr, "", &last, false);
+                                    }
+                                }
+
+                                // The delta is bits [51..61]
+                                // And bit 62 is to tell us if we are a rebase (0) or bind (1)
+                                value &= ~(1ULL << 62);
+                                delta = ( value & 0x3FF8000000000000 ) >> 51;
+                                segOffset += delta * sizeof(intptr_t);
+                            } while ( delta != 0 );
+                            break;
+                        }
+
+                        default:
+                            dyld::throwf("bad threaded bind subopcode 0x%02X", *p);
+                    }
+                    break;
                                default:
                                        dyld::throwf("bad bind opcode %d in bind info", *p);
                        }
@@ -1108,7 +1464,8 @@ void ImageLoaderMachOCompressed::eachLazyBind(const LinkContext& context, bind_h
                                                throwBadBindingAddress(address, segmentEndAddress, segmentIndex, start, end, p);
                                        if ( symbolName  == NULL )
                                                dyld::throwf("BIND_OPCODE_DO_BIND missing preceding BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM");
-                                       (this->*handler)(context, address, type, symbolName, symboFlags, addend, libraryOrdinal, "forced lazy ", NULL, false);
+                    handler(context, this, address, type, symbolName, symboFlags, addend, libraryOrdinal,
+                                     NULL, "forced lazy ", NULL, false);
                                        address += sizeof(intptr_t);
                                        break;
                                case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
@@ -1187,7 +1544,8 @@ uintptr_t ImageLoaderMachOCompressed::doBindLazySymbol(uintptr_t* lazyPointer, c
                                                        if ( !twoLevel || context.bindFlat ) 
                                                                libraryOrdinal = BIND_SPECIAL_DYLIB_FLAT_LOOKUP;
                                                        uintptr_t ptrToBind = (uintptr_t)lazyPointer;
-                                                       uintptr_t symbolAddr = bindAt(context, ptrToBind, BIND_TYPE_POINTER, symbolName, 0, 0, libraryOrdinal, "lazy ", NULL);
+                            uintptr_t symbolAddr = bindAt(context, this, ptrToBind, BIND_TYPE_POINTER, symbolName, 0, 0, libraryOrdinal,
+                                                          NULL, "lazy ", NULL);
                                                        ++fgTotalLazyBindFixups;
                                                        return symbolAddr;
                                                }
@@ -1233,7 +1591,8 @@ uintptr_t ImageLoaderMachOCompressed::doBindFastLazySymbol(uint32_t lazyBindingI
                if ( segOffset > segSize(segIndex) )
                        dyld::throwf("BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has offset 0x%08lX beyond segment size (0x%08lX)", segOffset, segSize(segIndex));
                uintptr_t address = segActualLoadAddress(segIndex) + segOffset;
-               result = this->bindAt(context, address, BIND_TYPE_POINTER, symbolName, 0, 0, libraryOrdinal, "lazy ", NULL, true);
+        result = bindAt(context, this, address, BIND_TYPE_POINTER, symbolName, 0, 0, libraryOrdinal,
+                              NULL, "lazy ", NULL, true);
                // <rdar://problem/24140465> Some old apps had multiple lazy symbols bound at once
        } while (!doneAfterBind && !context.strictMachORequired);
 
@@ -1426,17 +1785,17 @@ void ImageLoaderMachOCompressed::updateUsesCoalIterator(CoalIterator& it, uintpt
                                address += read_uleb128(p, end);
                                break;
                        case BIND_OPCODE_DO_BIND:
-                               bindLocation(context, address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ");
+                               bindLocation(context, this->imageBaseAddress(), address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ", NULL, fSlide);
                                boundSomething = true;
                                address += sizeof(intptr_t);
                                break;
                        case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
-                               bindLocation(context, address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ");
+                               bindLocation(context, this->imageBaseAddress(), address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ", NULL, fSlide);
                                boundSomething = true;
                                address += read_uleb128(p, end) + sizeof(intptr_t);
                                break;
                        case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
-                               bindLocation(context, address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ");
+                               bindLocation(context, this->imageBaseAddress(), address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ", NULL, fSlide);
                                boundSomething = true;
                                address += immediate*sizeof(intptr_t) + sizeof(intptr_t);
                                break;
@@ -1444,7 +1803,7 @@ void ImageLoaderMachOCompressed::updateUsesCoalIterator(CoalIterator& it, uintpt
                                count = read_uleb128(p, end);
                                skip = read_uleb128(p, end);
                                for (uint32_t i=0; i < count; ++i) {
-                                       bindLocation(context, address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ");
+                                       bindLocation(context, this->imageBaseAddress(), address, value, type, symbolName, addend, this->getPath(), targetImage ? targetImage->getPath() : NULL, "weak ", NULL, fSlide);
                                        boundSomething = true;
                                        address += skip + sizeof(intptr_t);
                                }
@@ -1458,13 +1817,16 @@ void ImageLoaderMachOCompressed::updateUsesCoalIterator(CoalIterator& it, uintpt
                context.addDynamicReference(this, targetImage);
 }
 
-uintptr_t ImageLoaderMachOCompressed::interposeAt(const LinkContext& context, uintptr_t addr, uint8_t type, const char*, 
-                                                                                               uint8_t, intptr_t, long, const char*, LastLookup*, bool runResolver)
+uintptr_t ImageLoaderMachOCompressed::interposeAt(const LinkContext& context, ImageLoaderMachOCompressed* image,
+                                                                                                 uintptr_t addr, uint8_t type, const char*,
+                                                  uint8_t, intptr_t, long,
+                                                  ExtraBindData *extraBindData,
+                                                  const char*, LastLookup*, bool runResolver)
 {
        if ( type == BIND_TYPE_POINTER ) {
                uintptr_t* fixupLocation = (uintptr_t*)addr;
                uintptr_t curValue = *fixupLocation;
-               uintptr_t newValue = interposedAddress(context, curValue, this);
+               uintptr_t newValue = interposedAddress(context, curValue, image);
                if ( newValue != curValue) {
                        *fixupLocation = newValue;
                }
@@ -1478,13 +1840,32 @@ void ImageLoaderMachOCompressed::doInterpose(const LinkContext& context)
                dyld::log("dyld: interposing %lu tuples onto image: %s\n", fgInterposingTuples.size(), this->getPath());
 
        // update prebound symbols
-       eachBind(context, &ImageLoaderMachOCompressed::interposeAt);
-       eachLazyBind(context, &ImageLoaderMachOCompressed::interposeAt);
+       eachBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                               uintptr_t addr, uint8_t type, const char* symbolName,
+                                               uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                               ExtraBindData *extraBindData,
+                                               const char* msg, LastLookup* last, bool runResolver) {
+               return ImageLoaderMachOCompressed::interposeAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                          addend, libraryOrdinal, extraBindData,
+                                                                                                          msg, last, runResolver);
+       });
+       eachLazyBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                                       uintptr_t addr, uint8_t type, const char* symbolName,
+                                                       uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                       ExtraBindData *extraBindData,
+                                                       const char* msg, LastLookup* last, bool runResolver) {
+               return ImageLoaderMachOCompressed::interposeAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                          addend, libraryOrdinal, extraBindData,
+                                                                                                          msg, last, runResolver);
+       });
 }
 
 
-uintptr_t ImageLoaderMachOCompressed::dynamicInterposeAt(const LinkContext& context, uintptr_t addr, uint8_t type, const char* symbolName, 
-                                                                                               uint8_t, intptr_t, long, const char*, LastLookup*, bool runResolver)
+uintptr_t ImageLoaderMachOCompressed::dynamicInterposeAt(const LinkContext& context, ImageLoaderMachOCompressed* image,
+                                                                                                                uintptr_t addr, uint8_t type, const char* symbolName,
+                                                         uint8_t, intptr_t, long,
+                                                         ExtraBindData *extraBindData,
+                                                         const char*, LastLookup*, bool runResolver)
 {
        if ( type == BIND_TYPE_POINTER ) {
                uintptr_t* fixupLocation = (uintptr_t*)addr;
@@ -1496,7 +1877,7 @@ uintptr_t ImageLoaderMachOCompressed::dynamicInterposeAt(const LinkContext& cont
                        if ( value == (uintptr_t)context.dynamicInterposeArray[i].replacee ) {
                                if ( context.verboseInterposing ) {
                                        dyld::log("dyld: dynamic interposing: at %p replace %p with %p in %s\n", 
-                                               fixupLocation, context.dynamicInterposeArray[i].replacee, context.dynamicInterposeArray[i].replacement, this->getPath());
+                                               fixupLocation, context.dynamicInterposeArray[i].replacee, context.dynamicInterposeArray[i].replacement, image->getPath());
                                }
                                *fixupLocation = (uintptr_t)context.dynamicInterposeArray[i].replacement;
                        }
@@ -1511,8 +1892,24 @@ void ImageLoaderMachOCompressed::dynamicInterpose(const LinkContext& context)
                dyld::log("dyld: dynamic interposing %lu tuples onto image: %s\n", context.dynamicInterposeCount, this->getPath());
 
        // update already bound references to symbols
-       eachBind(context, &ImageLoaderMachOCompressed::dynamicInterposeAt);
-       eachLazyBind(context, &ImageLoaderMachOCompressed::dynamicInterposeAt);
+       eachBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                               uintptr_t addr, uint8_t type, const char* symbolName,
+                                               uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                               ExtraBindData *extraBindData,
+                                               const char* msg, LastLookup* last, bool runResolver) {
+               return ImageLoaderMachOCompressed::dynamicInterposeAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                                         addend, libraryOrdinal, extraBindData,
+                                                                                                                         msg, last, runResolver);
+       });
+       eachLazyBind(context, ^(const LinkContext& ctx, ImageLoaderMachOCompressed* image,
+                                                       uintptr_t addr, uint8_t type, const char* symbolName,
+                                                       uint8_t symbolFlags, intptr_t addend, long libraryOrdinal,
+                                                       ExtraBindData *extraBindData,
+                                                       const char* msg, LastLookup* last, bool runResolver) {
+               return ImageLoaderMachOCompressed::dynamicInterposeAt(ctx, image, addr, type, symbolName, symbolFlags,
+                                                                                                                         addend, libraryOrdinal, extraBindData,
+                                                                                                                         msg, last, runResolver);
+       });
 }
 
 const char* ImageLoaderMachOCompressed::findClosestSymbol(const void* addr, const void** closestAddr) const