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cache_builder/NewSharedCacheBuilder.cpp dyld-1284.13 dyld-1235.2
--- dyld/dyld-1284.13/cache_builder/NewSharedCacheBuilder.cpp
+++ dyld/dyld-1235.2/cache_builder/NewSharedCacheBuilder.cpp
@@ -28,7 +28,6 @@
 #include "NewAdjustDylibSegments.h"
 #include "CacheDylib.h"
 #include "ClosureFileSystem.h"
-#include "JSONReader.h"
 #include "JSONWriter.h"
 #include "StringUtils.h"
 #include "Array.h"
@@ -40,7 +39,6 @@
 #include "JustInTimeLoader.h"
 #include "OptimizerObjC.h"
 #include "OptimizerSwift.h"
-#include "Platform.h"
 #include "PrebuiltLoader.h"
 #include "DyldProcessConfig.h"
 #include "DyldRuntimeState.h"
@@ -49,16 +47,7 @@
 #include "CString.h"
 #include "Version32.h"
 #include "ExternalGenericMetadataBuilderImport.h"
-#include "SnapshotShared.h"
-#include "AAREncoder.h"
 #include <SharedCacheLinker/SharedCacheLinker.h>
-#include "ThreadLocalVariables.h"
-
-// mach_o
-#include "ExportsTrie.h"
-#include "Header.h"
-#include "Image.h"
-#include "Misc.h"
 
 // FIXME: Remove this once we don't write to the old objc header struct.  See emitObjCOptsHeader()
 #include "objc-shared-cache.h"
@@ -71,7 +60,6 @@
 #include <sys/stat.h>
 #include <unordered_set>
 
-using mach_o::Header;
 using dyld3::GradedArchs;
 using dyld3::MachOFile;
 
@@ -79,21 +67,11 @@
 using dyld4::KernelArgs;
 using dyld4::Loader;
 using dyld4::ProcessConfig;
-using dyld4::RuntimeLocks;
 using dyld4::RuntimeState;
 using dyld4::SyscallDelegate;
 using dyld4::RuntimeLocks;
 
 using lsl::Allocator;
-
-using mach_o::Header;
-using mach_o::Platform;
-using mach_o::Image;
-using mach_o::ExportsTrie;
-using mach_o::Symbol;
-using mach_o::LinkedDylibAttributes;
-using mach_o::Version32;
-using error::Error;
 
 using metadata_visitor::SwiftConformance;
 using metadata_visitor::SwiftVisitor;
@@ -119,13 +97,9 @@
             // Note, don't change the form of this message without checking in with MRM, as they
             // parse it.  We really need to add structured errors/warnings some time
             std::string reason = "Dylib located at '" + inputFile.path + "' not placed in shared cache because: ";
-            for ( const error::Error& err : inputFile.getErrors() )
-                callback(reason + err.message());
-        }
-    }
-
-    for ( const std::string& warning : this->warnings )
-        callback(warning);
+            callback(reason + inputFile.getError().message());
+        }
+    }
 }
 
 void SharedCacheBuilder::forEachError(void (^callback)(const std::string_view& str)) const
@@ -159,30 +133,10 @@
 void SharedCacheBuilder::addFile(const void* buffer, size_t bufferSize, std::string_view path,
                                  uint64_t inode, uint64_t modTime, bool forceNotCacheEligible)
 {
+    Diagnostics diag;
     const bool  isOSBinary = false;
-    uint64_t    sliceOffset = 0;
     uint64_t    sliceLen = 0;
-
-    // On macOS, also allow iOSMac dylibs
-    if ( this->options.platform == Platform::macOS ) {
-        Diagnostics diag;
-        if ( const MachOFile* mf = MachOFile::compatibleSlice(diag, sliceOffset, sliceLen, buffer, bufferSize, path.data(),
-                                                              Platform::macCatalyst, isOSBinary,
-                                                              this->options.archs) ) {
-            InputFile inputFile;
-            inputFile.mf                    = mf;
-            inputFile.inode                 = inode;
-            inputFile.mtime                 = modTime;
-            inputFile.size                  = sliceLen;
-            inputFile.path                  = path;
-            inputFile.forceNotCacheEligible = forceNotCacheEligible;
-            allInputFiles.push_back(std::move(inputFile));
-            return;
-        }
-    }
-
-    Diagnostics diag;
-    if ( const MachOFile* mf = MachOFile::compatibleSlice(diag, sliceOffset, sliceLen, buffer, bufferSize, path.data(),
+    if ( const MachOFile* mf = MachOFile::compatibleSlice(diag, sliceLen, buffer, bufferSize, path.data(),
                                                           this->options.platform, isOSBinary,
                                                           this->options.archs) ) {
         InputFile inputFile;
@@ -196,32 +150,22 @@
         return;
     }
 
-    // If we have an error, then add an input file just in case its useful for later
-    if ( diag.hasError() ) {
-        // Only add dylibs to track for later error emission
-        __block bool isDylib = false;
-        const std::span<uint8_t> bufferSpan = { (uint8_t*)buffer, bufferSize };
-        mach_o::Error parseErr = mach_o::forEachHeader(bufferSpan, path,
-                                                       ^(const mach_o::Header* mh, size_t sliceHeader, bool& stop) {
-            if ( mh->isDylib() ) {
-                isDylib = true;
-                stop = true;
-            }
-        });
-
-        if ( !isDylib )
+    // On macOS, also allow iOSMac dylibs
+    if ( this->options.platform == dyld3::Platform::macOS ) {
+        diag.clearError();
+        if ( const MachOFile* mf = MachOFile::compatibleSlice(diag, sliceLen, buffer, bufferSize, path.data(),
+                                                              dyld3::Platform::iOSMac, isOSBinary,
+                                                              this->options.archs) ) {
+            InputFile inputFile;
+            inputFile.mf                    = mf;
+            inputFile.inode                 = inode;
+            inputFile.mtime                 = modTime;
+            inputFile.size                  = sliceLen;
+            inputFile.path                  = path;
+            inputFile.forceNotCacheEligible = forceNotCacheEligible;
+            allInputFiles.push_back(std::move(inputFile));
             return;
-
-        InputFile inputFile;
-        inputFile.mf                    = nullptr;
-        inputFile.inode                 = 0;
-        inputFile.mtime                 = 0;
-        inputFile.size                  = 0;
-        inputFile.path                  = path;
-        inputFile.forceNotCacheEligible = true;
-        inputFile.addError(Error("%s", (const char*)diag.errorMessageCStr()));
-        allInputFiles.push_back(std::move(inputFile));
-        return;
+        }
     }
 }
 
@@ -231,7 +175,6 @@
     this->inputAliases = aliases;
     this->inputIntermediateAliases = intermediateAliases;
 }
-
 
 //
 // MARK: --- SharedCacheBuilder build methods ---
@@ -304,9 +247,7 @@
 
     this->calculateCacheDylibsTrie();
     this->estimatePatchTableSize();
-    this->estimateFunctionVariantsSize();
     this->estimateCacheLoadersSize();
-    this->estimatePrewarmingSize();
 
     this->setupStubOptimizer();
 
@@ -344,10 +285,7 @@
 
 bool SharedCacheBuilder::shouldBuildSwiftPrespecializedDylib()
 {
-    if ( options.platform == Platform::driverKit )
-        return false;
-
-    if ( options.platform.isExclaveKit() )
+    if ( options.platform == dyld3::Platform::driverKit )
         return false;
 
     // build the dylib, only if the order file is defined
@@ -368,18 +306,18 @@
 #if !BUILDING_CACHE_BUILDER_UNIT_TESTS && !BUILDING_SIM_CACHE_BUILDER
     Timer::Scope timedScope(this->config, "buildSwiftPrespecializedDylibJSON time");
 
-    SwiftExternalMetadataBuilder* builder = swift_externalMetadataBuilder_create(options.platform.value(), options.archs.name());
+    SwiftExternalMetadataBuilder* builder = swift_externalMetadataBuilder_create((int)options.platform, options.archs.name());
     if ( !builder )
         return Error("swift_externalMetadataBuilder_create failed");
 
     for ( const CacheDylib& dylib : this->cacheDylibs ) {
-        if ( dylib.inputHdr == nullptr ) continue;
+        if ( dylib.inputMF == nullptr ) continue;
 
         // TODO: rdar://132262275 (dyld shared cache builder should tell Swift Metadata builder also about dyld)
-        if ( dylib.inputHdr->isDylinker() ) continue;
-
-        if ( const char* err = swift_externalMetadataBuilder_addDylib(builder, dylib.inputHdr->installName(),
-                (const struct mach_header*)dylib.inputHdr, dylib.inputFile->size) )
+        if ( dylib.inputMF->isDyld() ) continue;
+
+        if ( const char* err = swift_externalMetadataBuilder_addDylib(builder, dylib.inputMF->installName(),
+                (const struct mach_header*)dylib.inputMF, dylib.inputFile->size) )
             return Error("swift_externalMetadataBuilder_addDylib failed: %s", err);
     }
 
@@ -408,9 +346,9 @@
             if ( !endsWith(inputFile.path, "dyld") )
                 continue;
 
-            ((Header*)inputFile.mf)->platformAndVersions().unzip(^(mach_o::PlatformAndVersions pvs) {
-                if ( pvs.platform == options.platform )
-                    newMinOS = pvs.minOS;
+            inputFile.mf->forEachSupportedPlatform(^(dyld3::Platform platform, uint32_t currentMinOS, uint32_t sdk) {
+                if ( platform == options.platform )
+                    newMinOS = mach_o::Version32(currentMinOS);
             });
             break;
         }
@@ -516,8 +454,7 @@
     }
 
     Diagnostics diag;
-    uint64_t sliceOffset = 0;
-    inputFile->mf = MachOFile::compatibleSlice(diag, sliceOffset, inputFile->size, buffer, bufferSize, path.data(),
+    inputFile->mf = MachOFile::compatibleSlice(diag, inputFile->size, buffer, bufferSize, path.data(),
                                     this->options.platform, /* isOSBinary */ false,
                                     this->options.archs);
     if ( diag.hasError() )
@@ -525,7 +462,7 @@
 
     // recreate cache dylib at the reserved slot
     auto cacheDylibIt = std::find_if(cacheDylibs.begin(), cacheDylibs.end(), [](CacheDylib& dylib) {
-            return dylib.inputHdr == nullptr && dylib.installName == swiftPrespecializedDylibInstallName;
+            return dylib.inputMF == nullptr && dylib.installName == swiftPrespecializedDylibInstallName;
     });
     if ( cacheDylibIt == cacheDylibs.end() )
         return Error("missing cache dylib slot for Swift prespecialized dylib");
@@ -622,34 +559,30 @@
         if ( diag.hasError() )
             return Error("%s", diag.errorMessageCStr());
 
-        cacheDylib.bind(diag, this->config, aggregateTimer, dylibPatchInfo, this->functionVariantsOptimizer);
+        cacheDylib.bind(diag, this->config, aggregateTimer, dylibPatchInfo);
         if ( diag.hasError() )
             return Error("%s", diag.errorMessageCStr());
 
-        // Disable objc optimizations from EK shared cache
-        bool emitObjcOpts = !this->options.platform.isExclaveKit();
-        if ( emitObjcOpts ) {
-            cacheDylib.updateObjCSelectorReferences(diag, this->config, aggregateTimer, this->objcSelectorOptimizer);
-            if ( diag.hasError() )
-                return Error("%s", diag.errorMessageCStr());
-
-            cacheDylib.convertObjCMethodListsToOffsets(diag, this->config, aggregateTimer, this->objcSelectorOptimizer.selectorStringsChunk);
-            if ( diag.hasError() )
-                return Error("%s", diag.errorMessageCStr());
-
-            // Note, must be after updating selector references and converting relative methods to selector offsets
-            cacheDylib.sortObjCMethodLists(diag, this->config, aggregateTimer, this->objcSelectorOptimizer.selectorStringsChunk);
-            if ( diag.hasError() )
-                return Error("%s", diag.errorMessageCStr());
-
-            cacheDylib.optimizeLoadsFromConstants(this->config, aggregateTimer,
-                                                  this->objcSelectorOptimizer.selectorStringsChunk);
-
-            Error error = cacheDylib.emitObjCIMPCaches(this->config, aggregateTimer, this->objcIMPCachesOptimizer,
-                                                       this->objcSelectorOptimizer.selectorStringsChunk);
-            if ( error.hasError() )
-                return error;
-        }
+        cacheDylib.updateObjCSelectorReferences(diag, this->config, aggregateTimer, this->objcSelectorOptimizer);
+        if ( diag.hasError() )
+            return Error("%s", diag.errorMessageCStr());
+
+        cacheDylib.convertObjCMethodListsToOffsets(diag, this->config, aggregateTimer, this->objcSelectorOptimizer.selectorStringsChunk);
+        if ( diag.hasError() )
+            return Error("%s", diag.errorMessageCStr());
+
+        // Note, must be after updating selector references and converting relative methods to selector offsets
+        cacheDylib.sortObjCMethodLists(diag, this->config, aggregateTimer, this->objcSelectorOptimizer.selectorStringsChunk);
+        if ( diag.hasError() )
+            return Error("%s", diag.errorMessageCStr());
+
+        cacheDylib.optimizeLoadsFromConstants(this->config, aggregateTimer,
+                                              this->objcSelectorOptimizer.selectorStringsChunk);
+
+        Error error = cacheDylib.emitObjCIMPCaches(this->config, aggregateTimer, this->objcIMPCachesOptimizer,
+                                                   this->objcSelectorOptimizer.selectorStringsChunk);
+        if ( error.hasError() )
+            return error;
 
         cacheDylib.optimizeStubs(this->options, this->config, aggregateTimer, this->stubOptimizer,
                                  dylibPatchInfo);
@@ -669,55 +602,47 @@
 // Outputs: emitted optimizations in the subCache buffers
 Error SharedCacheBuilder::postDylibEmitChunks()
 {
-    // Disable objc optimizations from EK shared cache
-    bool emitObjcOpts = !this->options.platform.isExclaveKit();
-
-    if ( Error error = this->emitPrewarmingData(); error.hasError() )
-        return error;
 
     this->optimizeTLVs();
 
     if ( Error error = this->emitUniquedGOTs(); error.hasError() )
         return error;
 
-    if ( emitObjcOpts ) {
-        // Note this has to be before we emit the protocol hash table
-        if ( Error error = this->emitCanonicalObjCProtocols(); error.hasError() )
-            return error;
-    }
+    // Note this has to be before we emit the protocol hash table
+    if ( Error error = this->emitCanonicalObjCProtocols(); error.hasError() )
+        return error;
 
     this->emitCacheDylibsTrie();
     if ( Error error = this->emitPatchTable(); error.hasError() )
         return error;
 
-    this->emitFunctionVariants();
-
     // Note, this must be after we emit the patch table
     if ( Error error = this->emitCacheDylibsPrebuiltLoaders(); error.hasError() )
         return error;
 
-    if ( emitObjcOpts ) {
-        this->emitObjCHashTables();
-        
+    this->emitObjCHashTables();
+
+    bool preAttachedCategories = true;
+    if ( preAttachedCategories ) {
         // Note this has to be after anyone walking the objc metadata format
         if ( Error error = this->emitPreAttachedObjCCategories(); error.hasError() )
             return error;
-
-        // Note, this must be after emitCacheDylibsPrebuiltLoaders() as it needs the offset to the SectionLocations*
-        // in the PrebuiltLoader*
-        this->emitObjCHeaderInfo();
-        if ( Error error = this->computeObjCClassLayout(); error.hasError() )
+    }
+
+    // Note, this must be after emitCacheDylibsPrebuiltLoaders() as it needs the offset to the SectionLocations*
+    // in the PrebuiltLoader*
+    this->emitObjCHeaderInfo();
+    if ( Error error = this->computeObjCClassLayout(); error.hasError() )
         return error;
 
-        // Note this must be after computeObjCClassLayout() as we need it to set the flags for whether
-        // we have missing weak superclasses or not
-        this->emitObjCOptsHeader();
-
-        // Note, this has to be after we've emitted the objc class hash table, and after emitting
-        // the objc header info
-        if ( Error error = this->emitSwiftHashTables(); error.hasError() )
-            return error;
-    }
+    // Note this must be after computeObjCClassLayout() as we need it to set the flags for whether
+    // we have missing weak superclasses or not
+    this->emitObjCOptsHeader();
+
+    // Note, this has to be after we've emitted the objc class hash table, and after emitting
+    // the objc header info
+    if ( Error error = this->emitSwiftHashTables(); error.hasError() )
+        return error;
 
     // Note, this has to be after we've emitted the objc hash tables and the objc header infos
     if ( Error error = this->emitExecutablePrebuiltLoaders(); error.hasError() )
@@ -745,7 +670,6 @@
     this->addObjcSegments();
     this->computeCacheHeaders();
     this->codeSign();
-    this->buildAtlas();
 
     return Error();
 }
@@ -824,16 +748,6 @@
 
     for ( InputFile& inputFile : this->allInputFiles ) {
         if ( inputFile.mf == nullptr ) continue;
-
-        // only process valid images
-        if ( ((Header*)inputFile.mf)->isDyldManaged() ) {
-            // don't try to validate kernel or firmware mach-o binaries
-            Image image(inputFile.mf, inputFile.size, Image::MappingKind::wholeSliceMapped);
-            if ( mach_o::Error err = image.validate() ) {
-                inputFile.addError(Error("%s", err.message()));
-                continue;
-            }
-        }
 
         if ( inputFile.mf->isDylib() || inputFile.mf->isDyld() ) {
             auto failureHandler = ^(const char* format, ...) __attribute__((format(printf, 1, 2))) {
@@ -842,13 +756,13 @@
                 va_start(list, format);
                 vasprintf(&output_string, format, list);
                 va_end(list);
-                inputFile.addError(Error("%s", (const char*)output_string));
+                inputFile.setError(Error("%s", (const char*)output_string));
                 free(output_string);
             };
 
-            std::string_view installName = ((const Header*)inputFile.mf)->installName();
+            std::string_view installName = inputFile.mf->installName();
             std::string_view dylibPath = inputFile.path;
-            if ( (installName != dylibPath) && ((this->options.platform == Platform::macOS) || startsWith(dylibPath, "/System/Cryptexes/OS/")) ) {
+            if ( (installName != dylibPath) && ((this->options.platform == dyld3::Platform::macOS) || startsWith(dylibPath, "/System/Cryptexes/OS/")) ) {
                 // We now typically require that install names and paths match.  However symlinks may allow us to bring in a path which
                 // doesn't match its install name.
                 // For example:
@@ -868,7 +782,7 @@
                 }
             }
 
-            if ( !inputFile.forceNotCacheEligible && inputFile.mf->canBePlacedInDyldCache(dylibPath.data(), true /* check objc */, failureHandler) ) {
+            if ( !inputFile.forceNotCacheEligible && inputFile.mf->canBePlacedInDyldCache(dylibPath.data(), failureHandler) ) {
                 CacheDylib cacheDylib(inputFile);
                 this->cacheDylibs.push_back(std::move(cacheDylib));
             }
@@ -880,7 +794,7 @@
 
         if ( inputFile.mf->isDynamicExecutable() ) {
             auto failureHandler = ^(const char* reason) {
-                inputFile.addError(Error("%s", reason));
+                inputFile.setError(Error("%s", reason));
             };
             if ( inputFile.mf->canHavePrebuiltExecutableLoader(options.platform, inputFile.path, failureHandler) ) {
                 this->exeInputFiles.push_back(&inputFile);
@@ -901,23 +815,13 @@
 {
     Timer::Scope timedScope(this->config, "verifySelfContained time");
 
-    __block std::unordered_set<std::string_view> badDylibs;
-
-    __block std::unordered_map<std::string_view, const InputFile*> allDylibs;
+    __block std::unordered_set<std::string_view> allDylibs;
     allDylibs.reserve(this->allInputFiles.size());
     for ( const InputFile& inputFile : this->allInputFiles ) {
-        if ( inputFile.mf == nullptr ) {
-            // Add the file if its path looks like it might be cache eligible. This is
-            // better than getting no errors at all later
-            if ( inputFile.hasError() && Header::isSharedCacheEligiblePath(inputFile.path.data()) ) {
-                allDylibs.insert({ inputFile.path, &inputFile });
-                badDylibs.insert(inputFile.path);
-            }
-            continue;
-        }
+        if ( inputFile.mf == nullptr ) continue;
 
         if ( inputFile.mf->isDylib() )
-            allDylibs.insert({ ((const Header*)inputFile.mf)->installName(), &inputFile });
+            allDylibs.insert(inputFile.mf->installName());
     }
 
     __block std::unordered_set<std::string_view> potentialCacheDylibs;
@@ -925,10 +829,8 @@
     for ( const CacheDylib& cacheDylib : this->cacheDylibs )
         potentialCacheDylibs.insert(cacheDylib.installName);
 
-
-    // Keep track of all errors in case we need them to diagnose libsystem being missing
-    __block std::unordered_map<std::string_view, std::list<std::string>> missingDependencies;
-    __block std::unordered_map<std::string_view, std::list<std::string>> ineligibleDependencies;
+    __block std::unordered_set<std::string_view> badDylibs;
+
 
     // check all dependencies to assure every dylib in cache only depends on other dylibs in cache
     __block bool doAgain = true;
@@ -955,97 +857,33 @@
                         }
                     }
                 }
-
-                // Break weak edges, but only if we haven't seen the dylib.
-                if ( isWeak && (allDylibs.count(loadPath) == 0) )
-                    return;
-                if ( isWeak && allowedMissingWeakDylibs.count(loadPath) )
-                    return;
-
-                if ( badDylibs.count(loadPath) ) {
-                    std::string reason          = std::string("Depends on ineligible/bad dylib '") + loadPath + "'";
-                    cacheDylib.inputFile->addError(Error("%s", reason.c_str()));
+                if ( potentialCacheDylibs.count(loadPath) == 0 ) {
+                    // Break weak edges, but only if we haven't seen the dylib.
+                    if ( isWeak && (allDylibs.count(loadPath) == 0) )
+                        return;
+                    if ( isWeak && allowedMissingWeakDylibs.count(loadPath) )
+                        return;
+                    std::string reason          = std::string("Could not find dependency '") + loadPath + "'";
+                    cacheDylib.inputFile->setError(Error("%s", reason.c_str()));
                     badDylibs.insert(cacheDylib.installName);
-                    ineligibleDependencies[cacheDylib.installName].push_back(loadPath);
                     doAgain = true;
+                    stop    = true;
                     return;
                 }
 
-                if ( potentialCacheDylibs.count(loadPath) == 0 ) {
-                    std::string reason          = std::string("Could not find dependency '") + loadPath + "'";
-                    cacheDylib.inputFile->addError(Error("%s", reason.c_str()));
+                if ( badDylibs.count(loadPath) ) {
+                    // Break weak edges, but only if we haven't seen the dylib.
+                    if ( isWeak && (allDylibs.count(loadPath) == 0) )
+                        return;
+                    std::string reason          = std::string("Depends on ineligible/bad dylib '") + loadPath + "'";
+                    cacheDylib.inputFile->setError(Error("%s", reason.c_str()));
                     badDylibs.insert(cacheDylib.installName);
-                    missingDependencies[cacheDylib.installName].push_back(loadPath);
                     doAgain = true;
+                    stop    = true;
                     return;
                 }
             });
         }
-    }
-
-    // If libsystem is bad, give up, but try make a better error
-    for ( const CacheDylib& cacheDylib : this->cacheDylibs ) {
-        if ( cacheDylib.inputFile == nullptr )
-            continue;
-
-        if ( !cacheDylib.inputFile->hasError() )
-            continue;
-
-        bool isLibSystem = cacheDylib.installName.ends_with("/usr/lib/libSystem.dylib") || cacheDylib.installName.ends_with("/usr/lib/libSystem.B.dylib");
-        if ( !isLibSystem )
-            continue;
-
-        // Walk the dependency tree to try find the real error which caused us to fail
-        std::unordered_set<std::string> seenFiles;
-        std::list<std::string> worklist;
-        worklist.push_back(std::string(cacheDylib.installName));
-        while ( !worklist.empty() ) {
-            std::string dylibInstallName = worklist.back();
-            worklist.pop_back();
-
-            // Check if the dylib depends on something missing
-            // If so, we've found an issue
-            if ( auto it = missingDependencies.find(dylibInstallName); it != missingDependencies.end() ) {
-                for ( auto depInstallName : it->second ) {
-                    std::string reason = "Dylib located at '";
-                    reason += dylibInstallName;
-                    reason += "' not placed in shared cache because: ";
-                    reason += "Could not find dependency '";
-                    reason += depInstallName;
-                    reason += "'";
-                    this->errors.push_back(reason);
-                }
-            }
-
-            // Add bad dependencies to the worklist, hoping to eventually walk to the root cause
-            if ( auto dylibIt = ineligibleDependencies.find(dylibInstallName); dylibIt != ineligibleDependencies.end() ) {
-                for ( auto depInstallName : dylibIt->second ) {
-                    if ( seenFiles.count(depInstallName) )
-                        continue;
-
-                    seenFiles.insert(depInstallName);
-                    worklist.push_back(depInstallName);
-
-                    if ( auto depIt = allDylibs.find(depInstallName); depIt != allDylibs.end() ) {
-                        const InputFile* inputFile = depIt->second;
-                        // Walk the errors on this depenency, skip deps which are just more bad dylibs, and see if we can
-                        // find the root cause
-                        for ( const error::Error& err : inputFile->getErrors() ) {
-                            if ( err.messageContains("Depends on ineligible/bad dylib") )
-                                continue;
-
-                            std::string reason = "Dylib located at '";
-                            reason += depInstallName;
-                            reason += "' not placed in shared cache because: ";
-                            reason += err.message();
-                            this->errors.push_back(reason);
-                        }
-                    }
-                }
-            }
-        }
-
-        cacheDylibs.clear();
     }
 
     // Add bad dylibs to the "other" dylibs for use in prebuilt loaders
@@ -1205,7 +1043,7 @@
         // otherwise loading the library would pull in lots of other dependencies
         if ( swiftPrespecializedDylib && &cacheDylib == swiftPrespecializedDylib ) {
             if ( cacheDylib.dependents.empty() || cacheDylib.dependents.front().dylib->installName.find("libSystem") == std::string_view::npos ) {
-                diag.error("expected libSystem as the first linked dylib of %s", cacheDylib.inputHdr->installName());
+                diag.error("expected libSystem as the first linked dylib of %s", cacheDylib.inputMF->installName());
             } else {
                 cacheDylib.dependents.erase(cacheDylib.dependents.begin()+1, cacheDylib.dependents.end());
             }
@@ -1342,39 +1180,36 @@
 }
 
 static void forEachObjCMethodName(const CacheDylib& cacheDylib,
-                                  void (^callback)(const char* str))
-{
-    __block objc_visitor::Visitor objcVisitor = makeInputDylibObjCVisitor(cacheDylib);
-
-    auto visitPointerBasedMethod = ^(const objc_visitor::Method& method) {
-        const char* selectorString = method.getName(objcVisitor);
-        callback(selectorString);
-    };
-
-    auto visitMethodList = ^(const objc_visitor::MethodList& methodList) {
-        if ( methodList.numMethods() == 0 )
+                                  void (^callback)(std::string_view str))
+{
+    const MachOFile* mf = cacheDylib.inputMF;
+    mf->forEachSection(^(const MachOFile::SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
+        if ( strcmp(sectInfo.segInfo.segName, "__TEXT") != 0 )
             return;
-        if ( methodList.usesRelativeOffsets() )
+        if ( strcmp(sectInfo.sectName, "__objc_methname") != 0 )
             return;
-
-        // Check pointer based method lists
-        uint32_t numMethods = methodList.numMethods();
-        for ( uint32_t i = 0; i != numMethods; ++i ) {
-            const objc_visitor::Method& method = methodList.getMethod(objcVisitor, i);
-            visitPointerBasedMethod(method);
-        }
-    };
-
-    // selector references
-    objcVisitor.forEachSelectorReference(^(VMAddress selRefVMAddr, VMAddress selRefTargetVMAddr,
-                                           const char* selectorString) {
-        callback(selectorString);
-    });
-
-    // classes/categories/protocols/swift generics
-    objcVisitor.forEachMethodList(^(objc_visitor::MethodList& objcMethodList,
-                                    std::optional<metadata_visitor::ResolvedValue> extendedMethodTypes) {
-        visitMethodList(objcMethodList);
+        if ( sectInfo.segInfo.isProtected || ((sectInfo.sectFlags & SECTION_TYPE) != S_CSTRING_LITERALS) ) {
+            stop = true;
+            return;
+        }
+        if ( malformedSectionRange ) {
+            stop = true;
+            return;
+        }
+
+        // Use the file offset in the section to get the correct content
+        const char* content     = (const char*)mf + sectInfo.sectFileOffset;
+        uint64_t    sectionSize = sectInfo.sectSize;
+
+        const char* s   = (const char*)content;
+        const char* end = s + sectionSize;
+        while ( s < end ) {
+            std::string_view str = s;
+            callback(str);
+            s += str.size() + 1;
+        }
+
+        stop = true;
     });
 }
 
@@ -1859,7 +1694,7 @@
 void SharedCacheBuilder::findObjCDylibs()
 {
     // driverKit has no objc
-    if ( this->options.platform == Platform::driverKit )
+    if ( this->options.platform == dyld3::Platform::driverKit )
         return;
 
     Stats        stats(this->config);
@@ -1867,9 +1702,9 @@
 
     assert(this->objcOptimizer.objcDylibs.empty());
     for ( CacheDylib& cacheDylib : this->cacheDylibs ) {
-        if ( cacheDylib.inputHdr == nullptr ) continue;
-
-        if ( cacheDylib.inputHdr->hasObjC() )
+        if ( cacheDylib.inputMF == nullptr ) continue;
+
+        if ( cacheDylib.inputMF->hasObjC() )
             this->objcOptimizer.objcDylibs.push_back(&cacheDylib);
     }
 
@@ -1910,19 +1745,11 @@
     Error err = parallel::forEach(this->cacheDylibs, ^(size_t index, CacheDylib& cacheDylib) {
         std::vector<std::string_view>& strings = dylibSelectors[index];
 
-        __block std::unordered_set<const void*> seenStrings;
-        forEachObjCMethodName(cacheDylib, ^(const char* str) {
-            auto itAndInserted = seenStrings.insert(str);
-            if ( itAndInserted.second )
-                strings.push_back(str);
+        forEachObjCMethodName(cacheDylib, ^(std::string_view str) {
+            strings.push_back(std::move(str));
         });
 
-        // sort strings as we used to walk the __objc_methname section in order, so by sorting we
-        // should get close to possible to the old order
-        std::sort(strings.begin(), strings.end(), [](const std::string_view& a, const std::string_view& b) {
-            // note pointer comparison as we want the string location in the binary not its contents
-            return a.data() < b.data();
-        });
+        // FIXME: Walk selector references, classes, categories, protocols, etc
 
         return Error();
     });
@@ -2294,7 +2121,7 @@
     size_t objcIndex = 0;
     for (size_t cacheIndex = 0; cacheIndex < this->cacheDylibs.size(); cacheIndex++) {
         CacheDylib& cacheDylib = this->cacheDylibs[cacheIndex];
-        if ( !cacheDylib.inputHdr->hasObjC() )
+        if ( !cacheDylib.inputMF->hasObjC() )
             continue;
 
         // Skip dylibs with opcode fixups, as the Category visitor operates on chained fixups to find classes
@@ -2594,7 +2421,7 @@
     Stats        stats(this->config);
     Timer::Scope timedScope(this->config, "estimateSwiftHashTableSizes time");
 
-    this->swiftOptimizer.optsHeaderByteSize = sizeof(SwiftOptimizationHeader);
+    this->swiftProtocolConformanceOptimizer.optsHeaderByteSize = sizeof(SwiftOptimizationHeader);
 
     __block uint32_t numTypeConformances = 0;
     __block uint32_t numMetadataConformances = 0;
@@ -2640,7 +2467,7 @@
         });
     }
 
-    auto& optimizer = this->swiftOptimizer;
+    auto& optimizer = this->swiftProtocolConformanceOptimizer;
 
     if ( swiftPrespecializedDylib ) {
         Diagnostics diagVal;
@@ -2713,7 +2540,7 @@
 
     // For each alias, also see if we have intermediate aliases
     // This is the "Current -> A" symlink in say "/S/L/F/CF.fw/Current/CF"
-    if ( this->options.platform == Platform::macOS ) {
+    if ( this->options.platform == dyld3::Platform::macOS ) {
         for ( const cache_builder::FileAlias& alias : this->inputIntermediateAliases ) {
             const auto& pos = dylibPathToDylibIndex.find(alias.realPath);
             if ( pos != dylibPathToDylibIndex.end() ) {
@@ -2811,11 +2638,6 @@
     // 1 entry per location we bind to
     size += sizeof(dyld_cache_patchable_location_v4) * numBinds;
 
-#if BUILDING_CACHE_BUILDER_UNIT_TESTS
-    // HACK: This is temporary, until we have rdar://143965686, as unit tests are often so small their estimate is too low
-    size += 1024;
-#endif
-
     this->patchTableOptimizer.patchTableTotalByteSize = size;
     
     // Reserve space for the patch infos, one per dylib
@@ -2823,75 +2645,6 @@
 
     if ( this->config.log.printStats ) {
         stats.add("  patch table estimated size: %lld\n", (uint64_t)this->patchTableOptimizer.patchTableTotalByteSize);
-    }
-}
-
-void SharedCacheBuilder::estimateFunctionVariantsSize()
-{
-    this->functionVariantsOptimizer.fvInfoTotalByteSize = sizeof(dyld_cache_function_variant_entry) * 256;  // FIXME
-
-}
-
-void SharedCacheBuilder::estimatePrewarmingSize()
-{
-    // Skip everything if the JSON file is empty
-    if ( this->options.prewarmingOptimizations.empty() )
-        return;
-
-    using json::Node;
-    using json::NodeValueType;
-
-    Stats        stats(this->config);
-    Timer::Scope timedScope(this->config, "estimatePrewarmingSize time");
-
-    Diagnostics diag;
-    Node rootNode = json::readJSON(diag, this->options.prewarmingOptimizations.data(),
-                                   this->options.prewarmingOptimizations.size(),
-                                   false /* useJSON5 */);
-    if ( diag.hasError() )
-        return;
-
-    // Format is something like:
-    // [
-    //     {
-    //         "install_name": "..."
-    //         "locations": [
-    //             {
-    //                 "name": "symbol name",
-    //                 "offset": 0
-    //             }
-    //         ]
-    //     },
-    // ...
-    // ]
-    if ( rootNode.type != NodeValueType::Array )
-        return;
-
-    uint64_t numElements = 0;
-    for ( const Node& fileNode : rootNode.array ) {
-        auto locationsIt = fileNode.map.find("locations");
-        if ( locationsIt == fileNode.map.end() ) {
-            // FIXME: Should we error out if the JSON isn't what we expect
-            // For now just skip bad data
-            continue;
-        }
-
-        if ( locationsIt->second.type != NodeValueType::Array ) {
-            // FIXME: Should we error out if the JSON isn't what we expect
-            // For now just skip bad data
-            continue;
-        }
-
-        numElements += locationsIt->second.array.size();
-    }
-
-    this->prewarmingOptimizer.prewarmingByteSize = 0;
-    this->prewarmingOptimizer.prewarmingByteSize += sizeof(dyld_prewarming_header);
-    this->prewarmingOptimizer.prewarmingByteSize += numElements * sizeof(dyld_prewarming_entry);
-    this->prewarmingOptimizer.prewarmingByteSize = (uint32_t)alignTo((uint64_t)this->prewarmingOptimizer.prewarmingByteSize, 8);
-
-    if ( this->config.log.printStats ) {
-        stats.add("  dyld4 prewarming estimated size: %lld\n", (uint64_t)this->prewarmingOptimizer.prewarmingByteSize);
     }
 }
 
@@ -2915,7 +2668,7 @@
             size += sizeof(Loader::Region) * cacheDylib.segments.size();
 
             // iOSMac dylibs likely contain a patch table
-            if ( (this->options.platform == Platform::macOS)
+            if ( (this->options.platform == dyld3::Platform::macOS)
                 && startsWith(cacheDylib.installName, "/System/iOSSupport") ) {
                 __block Diagnostics diag;
                 cacheDylib.inputMF->withFileLayout(diag, ^(const mach_o::Layout& layout) {
@@ -2950,7 +2703,7 @@
         // Assumes that cdHash strings at runtime use lowercase a-f digits
         uint32_t codeSignFileOffset = 0;
         uint32_t codeSignFileSize   = 0;
-        if ( ((const Header*)inputFile->mf)->hasCodeSignature(codeSignFileOffset, codeSignFileSize) ) {
+        if ( inputFile->mf->hasCodeSignature(codeSignFileOffset, codeSignFileSize) ) {
             auto handler = ^(const uint8_t cdHash[20]) {
                 std::string cdHashStr = "/cdhash/";
                 cdHashStr.reserve(24);
@@ -3032,10 +2785,6 @@
 // This adds all of them to the given subCache
 void SharedCacheBuilder::addObjCOptimizationsToSubCache(SubCache& subCache)
 {
-    // Disable objc optimizations for EK
-    if ( this->options.platform.isExclaveKit() )
-        return;
-
     // Add objc header info RW
     subCache.addObjCHeaderInfoReadWriteChunk(this->config, this->objcOptimizer);
 
@@ -3046,7 +2795,7 @@
     subCache.addObjCCategoriesChunk(this->config, this->objcCategoryOptimizer);
 
     // Add objc opts header
-    subCache.addObjCOptsHeaderChunk(this->config, this->objcOptimizer);
+    subCache.addObjCOptsHeaderChunk(this->objcOptimizer);
 
     // Add objc header info RO
     subCache.addObjCHeaderInfoReadOnlyChunk(this->config, this->objcOptimizer);
@@ -3071,16 +2820,16 @@
     subCache.addObjCProtocolSwiftDemangledNamesChunk(this->config, this->objcProtocolOptimizer);
 
     // Add ObjC IMP Caches
-    subCache.addObjCIMPCachesChunk(this->config, this->objcIMPCachesOptimizer);
+    subCache.addObjCIMPCachesChunk(this->objcIMPCachesOptimizer);
 
     // Add Swift opts header
-    subCache.addSwiftOptsHeaderChunk(this->config, this->swiftOptimizer);
+    subCache.addSwiftOptsHeaderChunk(this->swiftProtocolConformanceOptimizer);
 
     // Add Swift hash tables
-    subCache.addSwiftTypeHashTableChunk(this->config, this->swiftOptimizer);
-    subCache.addSwiftMetadataHashTableChunk(this->config, this->swiftOptimizer);
-    subCache.addSwiftForeignHashTableChunk(this->config, this->swiftOptimizer);
-    subCache.addSwiftPrespecializedMetadataPointerTableChunks(this->config, this->swiftOptimizer);
+    subCache.addSwiftTypeHashTableChunk(this->swiftProtocolConformanceOptimizer);
+    subCache.addSwiftMetadataHashTableChunk(this->swiftProtocolConformanceOptimizer);
+    subCache.addSwiftForeignHashTableChunk(this->swiftProtocolConformanceOptimizer);
+    subCache.addSwiftPrespecializedMetadataPointerTableChunks(this->swiftProtocolConformanceOptimizer);
 }
 
 // The shared cache contains many global optimizations such as dyld4 loaders, trie's, etc.
@@ -3094,9 +2843,6 @@
     // Add patch table
     subCache.addPatchTableChunk(this->patchTableOptimizer);
 
-    // Add function-variants table
-    subCache.addFunctionVariantsChunk(this->functionVariantsOptimizer);
-
     // Add cache dylib Loader's
     subCache.addCacheDylibsLoaderChunk(this->prebuiltLoaderBuilder);
 
@@ -3105,9 +2851,6 @@
 
     // Add executable trie
     subCache.addExecutablesTrieChunk(this->prebuiltLoaderBuilder);
-
-    // Add prewarming data
-    subCache.addPrewarmingDataChunk(this->config, this->prewarmingOptimizer);
 }
 
 // Every subCache needs a code signature, and subCache's with DATA* need slide info.  This adds
@@ -3143,15 +2886,16 @@
             continue;
 
         const MachOFile* mf = textChunk->inputFile->mf;
-        ((const Header*)mf)->forEachSection(^(const Header::SectionInfo &sectInfo, bool &stop) {
-            if ( textChunk->segmentName != sectInfo.segmentName )
+        mf->forEachSection(^(const dyld3::MachOFile::SectionInfo &sectInfo,
+                             bool malformedSectionRange, bool &stop) {
+            if ( textChunk->segmentName != sectInfo.segInfo.segName )
                 return;
 
-            unsigned sectionType = (sectInfo.flags & SECTION_TYPE);
+            unsigned sectionType = (sectInfo.sectFlags & SECTION_TYPE);
             if ( sectionType != S_SYMBOL_STUBS )
                 return;
 
-            if ( sectInfo.segmentName != "__TEXT" ) {
+            if ( strcmp(sectInfo.segInfo.segName, "__TEXT") != 0 ) {
                 // stubs aren't in __TEXT.  Give up on this one for now
                 return;
             }
@@ -3163,13 +2907,13 @@
 
             if ( mf->isArch("arm64e") ) {
                 // For arm64e, we can only optimize __auth_stubs
-                if ( sectInfo.sectionName == "__auth_stubs" ) {
+                if ( !strcmp(sectInfo.sectName, "__auth_stubs") ) {
                     devStubsChunk       = &cacheDylib->developmentStubs;
                     customerStubsChunk  = &cacheDylib->customerStubs;
                 }
             } else {
                 // For non-arm64e, we can only optimize __stubs
-                if ( sectInfo.sectionName == "__stubs" ) {
+                if ( !strcmp(sectInfo.sectName, "__stubs") ) {
                     devStubsChunk       = &cacheDylib->developmentStubs;
                     customerStubsChunk  = &cacheDylib->customerStubs;
                 }
@@ -3179,17 +2923,17 @@
                 return;
 
             assert(devStubsChunk->segmentName.empty());
-            devStubsChunk->segmentName = sectInfo.segmentName;
-            devStubsChunk->sectionName = sectInfo.sectionName;
-            devStubsChunk->subCacheFileSize = CacheFileSize(sectInfo.size);
-            devStubsChunk->cacheVMSize = CacheVMSize(sectInfo.size);
+            devStubsChunk->segmentName = sectInfo.segInfo.segName;
+            devStubsChunk->sectionName = sectInfo.sectName;
+            devStubsChunk->subCacheFileSize = CacheFileSize(sectInfo.sectSize);
+            devStubsChunk->cacheVMSize = CacheVMSize(sectInfo.sectSize);
             devStubsSubCache.addStubsChunk(devStubsChunk);
 
             assert(customerStubsChunk->segmentName.empty());
-            customerStubsChunk->segmentName = sectInfo.segmentName;
-            customerStubsChunk->sectionName = sectInfo.sectionName;
-            customerStubsChunk->subCacheFileSize = CacheFileSize(sectInfo.size);
-            customerStubsChunk->cacheVMSize = CacheVMSize(sectInfo.size);
+            customerStubsChunk->segmentName = sectInfo.segInfo.segName;
+            customerStubsChunk->sectionName = sectInfo.sectName;
+            customerStubsChunk->subCacheFileSize = CacheFileSize(sectInfo.sectSize);
+            customerStubsChunk->cacheVMSize = CacheVMSize(sectInfo.sectSize);
             customerStubsSubCache.addStubsChunk(customerStubsChunk);
         });
     }
@@ -3318,43 +3062,6 @@
             }
         }
 
-        // Also split the current file so that read-only are in their own files
-        {
-            // Create a new subCache
-            newSubCaches.push_back(SubCache::makeSubCache(options));
-            SubCache& newSubCache = newSubCaches.back();
-
-            // Move all data to the new subCache
-            for ( Region& oldRegion : subCache.regions ) {
-                if ( oldRegion.chunks.empty() )
-                    continue;
-
-                // Move all the data regions, leave the rest
-                switch ( oldRegion.kind ) {
-                    case cache_builder::Region::Kind::text:
-                    case cache_builder::Region::Kind::dataConst:
-                    case cache_builder::Region::Kind::tproConst:
-                    case cache_builder::Region::Kind::data:
-                    case cache_builder::Region::Kind::auth:
-                    case cache_builder::Region::Kind::authConst:
-                    case cache_builder::Region::Kind::tproAuthConst:
-                        // Nothing to do here
-                        break;
-                    case cache_builder::Region::Kind::readOnly:{
-                        Region& newRegion = newSubCache.regions[(uint32_t)oldRegion.kind];
-                        newRegion.chunks = std::move(oldRegion.chunks);
-                        break;
-                    }
-                    case cache_builder::Region::Kind::linkedit:
-                    case cache_builder::Region::Kind::unmapped:
-                    case cache_builder::Region::Kind::dynamicConfig:
-                    case cache_builder::Region::Kind::codeSignature:
-                    case cache_builder::Region::Kind::numKinds:
-                        break;
-                }
-            }
-        }
-
         // Done splitting the current subCache, so move it from the source list to the new list
         newSubCaches.push_back(std::move(subCache));
     }
@@ -3367,96 +3074,39 @@
 {
     SubCache* currentSubCache = firstSubCache;
 
-    std::string_view libObjcInstallName = "/usr/lib/libobjc.A.dylib";
-    if ( this->options.platform.isExclaveKit() )
-        libObjcInstallName = "/System/ExclaveKit/usr/lib/libobjc.A.dylib";
-
-    // If we have an objc dylib, then gets its optimizations now to work out their size first
-    // The subCache with libobjc gets the header info sections, which for now we assume is the first subcache
-    // Add all the objc tables.  This must be done before we add libobjc's __TEXT
+    // Walk all the dylibs, and create a new subCache every time we are about to cross
+    // the subCacheTextLimit
+    CacheVMSize subCacheTextSize(0ULL);
     for ( CacheDylib& cacheDylib : this->cacheDylibs ) {
-        if ( cacheDylib.installName == libObjcInstallName ) {
+        // Peek ahead to find the __TEXT size
+        CacheVMSize textSize(0ULL);
+        for ( DylibSegmentChunk& segmentInfo : cacheDylib.segments ) {
+            if ( segmentInfo.kind == DylibSegmentChunk::Kind::dylibText )
+                textSize += segmentInfo.cacheVMSize;
+        }
+
+        // If we exceed the current limit, then the current subCache is complete and we need
+        // to start a new one
+        if ( (subCacheTextSize + textSize) > this->config.layout.subCacheTextLimit ) {
+            // Create a new subCache
+            otherCaches.push_back(SubCache::makeSubCache(this->options));
+            currentSubCache = &otherCaches.back();
+
+            // Reset the limit for the next subCache
+            subCacheTextSize = CacheVMSize(0ULL);
+        }
+
+        subCacheTextSize += textSize;
+
+        // The subCache with libobjc gets the header info sections
+        // Add all the objc tables.  This must be done before we add libobjc's __TEXT
+        std::string_view libObjcInstallName = "/usr/lib/libobjc.A.dylib";
+        if ( dyld3::MachOFile::isExclaveKitPlatform(this->options.platform) )
+            libObjcInstallName = "/System/ExclaveKit/usr/lib/libobjc.A.dylib";
+        if ( cacheDylib.installName == libObjcInstallName )
             this->addObjCOptimizationsToSubCache(*currentSubCache);
-            break;
-        }
-    }
-
-    // Walk all the dylibs, and create a new subCache every time we are about to cross
-    // the subCache size limit
-    if ( this->config.layout.discontiguous.has_value() ) {
-        const CacheVMSize subCacheTextLimit = this->config.layout.discontiguous.value().subCacheTextLimit;
-        CacheVMSize subCacheTextSize(0ULL);
-        for ( CacheDylib& cacheDylib : this->cacheDylibs ) {
-            // Peek ahead to find the __TEXT size
-            CacheVMSize textSize(0ULL);
-            for ( DylibSegmentChunk& segmentInfo : cacheDylib.segments ) {
-                if ( segmentInfo.kind == DylibSegmentChunk::Kind::dylibText )
-                    textSize += segmentInfo.cacheVMSize;
-            }
-
-            // If we exceed the current limit, then the current subCache is complete and we need
-            // to start a new one
-            if ( (subCacheTextSize + textSize) > subCacheTextLimit ) {
-                // Create a new subCache
-                otherCaches.push_back(SubCache::makeSubCache(this->options));
-                currentSubCache = &otherCaches.back();
-
-                // Reset the limit for the next subCache
-                subCacheTextSize = CacheVMSize(0ULL);
-            }
-
-            subCacheTextSize += textSize;
-
-            currentSubCache->addDylib(this->config, cacheDylib);
-            currentSubCache->addLinkeditFromDylib(cacheDylib);
-        }
-    } else {
-        const CacheVMSize subCacheTextDataLimit = this->config.layout.contiguous.value().subCacheTextDataLimit;
-        const CacheVMSize regionPadding = this->config.layout.contiguous.value().subCachePadding;
-        CacheVMSize subCacheTextDataSize(regionPadding);
-
-        // If we added any objc optimizations, then take their size in to account now
-        for ( const Region& region : currentSubCache->regions ) {
-            if ( region.kind == Region::Kind::linkedit )
-                continue;
-            if ( region.chunks.empty() )
-                continue;
-            for ( const Chunk* chunk : region.chunks ) {
-                // Assume the worst in terms of padding, ie, that every segment is preceded by the max
-                // possible number of padding bytes
-                subCacheTextDataSize += CacheVMSize(chunk->alignment()) + chunk->cacheVMSize;
-            }
-        }
-
-        for ( CacheDylib& cacheDylib : this->cacheDylibs ) {
-            // Peek ahead to find the __TEXT size
-            CacheVMSize textDataSize(0ULL);
-            for ( DylibSegmentChunk& segmentInfo : cacheDylib.segments ) {
-                if ( segmentInfo.kind == DylibSegmentChunk::Kind::dylibLinkedit )
-                    continue;
-
-                // Assume the worst in terms of padding, ie, that every segment is preceded by the max
-                // possible number of padding bytes
-                textDataSize += CacheVMSize(segmentInfo.alignment()) + segmentInfo.cacheVMSize;
-            }
-
-            // If we exceed the current limit, then the current subCache is complete and we need
-            // to start a new one
-            if ( (subCacheTextDataSize + textDataSize) > subCacheTextDataLimit ) {
-                // Create a new subCache
-                otherCaches.push_back(SubCache::makeSubCache(this->options));
-                currentSubCache = &otherCaches.back();
-
-                // Reset the limit for the next subCache
-                subCacheTextDataSize = CacheVMSize(regionPadding);
-            }
-
-            subCacheTextDataSize += textDataSize;
-
-            // We'll add LINKEDIT at the end, not here
-            currentSubCache->addDylib(this->config, cacheDylib);
-            currentSubCache->addLinkeditFromDylib(cacheDylib);
-        }
+
+        currentSubCache->addDylib(this->config, cacheDylib);
     }
 
     // Add all the remaining content in to the final (current) subCache
@@ -4107,55 +3757,17 @@
     return Error();
 }
 
-// returns empty string if symbol is in specified boundDylibName,
-// otherwise it return where symbol actually is defined
-static CString getActualSymbolImplDylib(CString symbolName, CString boundDylibName,
-                                        const std::unordered_map<std::string_view, CacheDylib*>& installNameToDylibMap,
-                                        bool& symbolImplIsFunctionVariant, uint16_t& functionVariantIndex)
-{
-    // find if bind target is really in another dylib or is a function variant
-    __block CString betterDylib;
-    const auto& posi = installNameToDylibMap.find(boundDylibName);
-    if ( posi != installNameToDylibMap.end() ) {
-        CacheDylib* targetDylib = posi->second;
-        Image       targetImage(targetDylib->inputMF, targetDylib->inputFile->size, Image::MappingKind::wholeSliceMapped);
-        Symbol      symbol;
-        if ( targetImage.exportsTrie().hasExportedSymbol(symbolName.c_str(), symbol) ) {
-            betterDylib = (const char*)(targetDylib->installName.data()); // FIXME
-            uint32_t fvi;
-            if (symbol.isFunctionVariant(fvi) ) {
-                symbolImplIsFunctionVariant = true;
-                functionVariantIndex        = fvi;
-            }
-        }
-        else {
-            // check if symbol is from re-exported dylib
-            const Header* targetHdr = (Header*)targetDylib->inputMF;
-            targetHdr->forEachLinkedDylib(^(const char* loadPath, LinkedDylibAttributes kind, Version32 compatVersion, Version32 curVersion, bool synthesizedLink, bool &stop) {
-                if ( kind.reExport ) {
-                    betterDylib = getActualSymbolImplDylib(symbolName, loadPath, installNameToDylibMap, symbolImplIsFunctionVariant, functionVariantIndex);
-                    if ( !betterDylib.empty() ) {
-                        stop = true;
-                    }
-                }
-            });
-        }
-    }
-    return betterDylib;
-}
-
-
 static void parseGOTs(const CacheDylib* dylib, const DylibSegmentChunk* chunk,
                       std::string_view segmentName, std::string_view sectionName,
-                      const std::unordered_map<std::string_view, CacheDylib*>& installNameToDylibMap,
                       DylibSectionCoalescer::OptimizedSection& dylibOptimizedSection)
 {
+    const MachOFile* mf = dylib->inputMF;
     __block Diagnostics diag;
 
     const bool log = false;
 
     // Skip ineligible dylibs
-    if ( !dylib->inputMF->hasChainedFixups() )
+    if ( !mf->hasChainedFixups() )
         return;
 
     // Some dylibs have auth gots in segments other than __AUTH_CONST. Skip them for now
@@ -4163,7 +3775,7 @@
         return;
 
     __block bool supportsGOTUniquing = false;
-    dylib->inputMF->withFileLayout(diag, ^(const mach_o::Layout& layout) {
+    mf->withFileLayout(diag, ^(const mach_o::Layout& layout) {
         mach_o::SplitSeg splitSeg(layout);
 
         if ( splitSeg.isV2() )
@@ -4173,11 +3785,13 @@
     if ( !supportsGOTUniquing )
         return;
 
-    if ( dylib->inputHdr->isArch("x86_64") || dylib->inputHdr->isArch("x86_64h") ) {
+    if ( mf->isArch("x86_64") || mf->isArch("x86_64h") ) {
         __block bool oldLinker = false;
-        dylib->inputHdr->forEachBuildTool(^(Platform platform, uint32_t tool, uint32_t version) {
+        mf->forEachSupportedBuildTool(^(dyld3::Platform platform, uint32_t tool, uint32_t version) {
             uint32_t majorVersion = version >> 16;
-            
+            // uint32_t minorVersion = (version >> 8) && 0xFF;
+            // uint32_t veryMinorVersion = version && 0xFF;
+
             if ( tool == TOOL_LD ) {
                 if ( majorVersion < 803 )
                     oldLinker = true;
@@ -4189,37 +3803,37 @@
     }
 
     // rdar://89319146
-    if ( dylib->inputHdr->isArch("x86_64") || dylib->inputHdr->isArch("x86_64h") ) {
-        if ( !strcmp(dylib->inputHdr->installName(), "/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation") )
+    if ( mf->isArch("x86_64") || mf->isArch("x86_64h") ) {
+        if ( !strcmp(mf->installName(), "/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation") )
             return;
-        if ( !strcmp(dylib->inputHdr->installName(), "/usr/lib/system/libdispatch.dylib") )
+        if ( !strcmp(mf->installName(), "/usr/lib/system/libdispatch.dylib") )
             return;
     }
 
     // rdar://86911139
-    if ( dylib->inputHdr->builtForPlatform(Platform::iOS)
-        && !strcmp(dylib->inputHdr->installName(), "/System/Library/PrivateFrameworks/CoreUI.framework/CoreUI") )
+    if ( mf->builtForPlatform(dyld3::Platform::iOS)
+        && !strcmp(mf->installName(), "/System/Library/PrivateFrameworks/CoreUI.framework/CoreUI") )
         return;
 
     // Dylib segment is eligible.  Walk the GOTs
-    __block std::optional<std::pair<Header::SegmentInfo, Header::SectionInfo>> gotSectionInfo;
+    __block std::optional<dyld3::MachOAnalyzer::SectionInfo> gotSectionInfo;
     __block uint16_t chainedFixupFormat = 0;
-    dylib->inputHdr->forEachSection(^(const Header::SegmentInfo& segInfo, const Header::SectionInfo& sectInfo, bool& stop) {
-        if ( sectInfo.segmentName != segmentName )
+    mf->forEachSection(^(const dyld3::MachOAnalyzer::SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
+        if ( sectInfo.segInfo.segName != segmentName )
             return;
-        if ( sectInfo.sectionName != sectionName)
+        if ( sectInfo.sectName != sectionName)
             return;
-        gotSectionInfo = { segInfo, sectInfo };
+        gotSectionInfo = sectInfo;
 
         // As we found the section we want, also get its chained fixup format
-        dylib->inputMF->withFileLayout(diag, ^(const mach_o::Layout& layout) {
+        mf->withFileLayout(diag, ^(const mach_o::Layout& layout) {
             mach_o::Fixups fixups(layout);
 
             fixups.withChainStarts(diag, ^(const dyld_chained_starts_in_image* starts) {
                 MachOFile::forEachFixupChainSegment(diag, starts,
                                                     ^(const dyld_chained_starts_in_segment* segmentInfo,
                                                       uint32_t segIndex, bool& stopSegment) {
-                    if ( segIndex == sectInfo.segIndex ) {
+                    if ( segIndex == sectInfo.segInfo.segIndex ) {
                         chainedFixupFormat = segmentInfo->pointer_format;
                         stopSegment = true;
                     }
@@ -4238,7 +3852,7 @@
         return;
 
     __block std::vector<mach_o::Fixups::BindTargetInfo> bindTargets;
-    dylib->inputMF->withFileLayout(diag, ^(const mach_o::Layout& layout) {
+    mf->withFileLayout(diag, ^(const mach_o::Layout& layout) {
         mach_o::Fixups fixups(layout);
 
         fixups.forEachBindTarget(diag, false, 0, ^(const mach_o::Fixups::BindTargetInfo& info, bool& stop) {
@@ -4255,22 +3869,20 @@
         return;
 
     __block std::vector<const char*> dependents;
-    dylib->inputMF->forEachDependentDylib(^(const char *loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool &stop) {
+    mf->forEachDependentDylib(^(const char *loadPath, bool isWeak, bool isReExport, bool isUpward, uint32_t compatVersion, uint32_t curVersion, bool &stop) {
         dependents.push_back(loadPath);
     });
 
-    bool hasFunctionVariantFixups = dylib->inputHdr->hasFunctionVariantFixups();
-
     auto* cacheGotSection = (CoalescedGOTSection*)dylibOptimizedSection.subCacheSection;
     DylibSectionCoalescer::DylibSectionOffsetToCacheSectionOffset& offsetMap = dylibOptimizedSection.offsetMap;
 
     // Walk the entries in this section
     // File layout so just add the file offset
-    const uint8_t* content      = (const uint8_t*)dylib->inputHdr + gotSectionInfo->second.fileOffset;
+    const uint8_t* content      = (const uint8_t*)mf + gotSectionInfo->sectFileOffset;
     const uint8_t* pos          = content;
-    const uint8_t* end          = content + gotSectionInfo->second.size;
-    uint32_t       pointerSize  = dylib->inputHdr->pointerSize();
-    assert((gotSectionInfo->second.size % pointerSize == 0));
+    const uint8_t* end          = content + gotSectionInfo->sectSize;
+    uint32_t       pointerSize  = mf->pointerSize();
+    assert((gotSectionInfo->sectSize % pointerSize == 0));
     while ( pos != end ) {
         const dyld3::MachOLoaded::ChainedFixupPointerOnDisk* fixup = (const dyld3::MachOLoaded::ChainedFixupPointerOnDisk*)pos;
         pos += pointerSize;
@@ -4281,67 +3893,30 @@
         uint32_t sourceSectionOffset = (uint32_t)((uint64_t)fixup - (uint64_t)content);
 
         // Note down rebases, but otherwise skip them
-        __block bool     targetIsFunctionVariant  = false;
-        __block uint16_t functionVariantIndex     = 0;
         if ( !isBind ) {
-            if ( hasFunctionVariantFixups ) {
-                // see if this rebase is the local of an internal function variant
-                Image image(dylib->inputHdr, dylib->inputFile->size, Image::MappingKind::wholeSliceMapped);
-                uint32_t segIndex = gotSectionInfo->first.segmentIndex;
-                image.functionVariantFixups().forEachFixup(^(mach_o::FunctionVariantFixups::InternalFixup fixupInfo) {
-                    if ( fixupInfo.segIndex != segIndex )
-                        return;
-                    uint64_t segOffset = sourceSectionOffset + gotSectionInfo->second.address - gotSectionInfo->first.vmaddr;
-                    if ( fixupInfo.segOffset == segOffset ) {
-                        targetIsFunctionVariant = true;
-                        functionVariantIndex = fixupInfo.variantIndex;
-                    }
-                });
-            }
-            if ( !targetIsFunctionVariant ) {
-                dylibOptimizedSection.unoptimizedOffsets.insert(sourceSectionOffset);
-                continue;
-            }
-        }
-
-        const CacheDylib*           targetDylib          = nullptr;
-        CoalescedGOTSection::GOTKey key;
-        if ( targetIsFunctionVariant ) {
-            MachOFile::PointerMetaData pmd(fixup, chainedFixupFormat);
-            char* synthName;
-            asprintf(&synthName, "internal-function-variant#%d", functionVariantIndex);
-            key         = { synthName, dylib->installName, pmd, false, true };
-            targetDylib = dylib;
-        }
-        else {
-            // We don't support addends right now.  But hopefully GOTs don't need them anyway
-            if ( addend != 0 )
-                continue;
-
-            const mach_o::Fixups::BindTargetInfo& bindTarget = bindTargets[bindOrdinal];
-
-            // TODO: Weak GOTs.  See rdar://86510941
-            const char* targetInstallName = nullptr;
-            if ( (bindTarget.libOrdinal > 0) && ((unsigned)bindTarget.libOrdinal <= dependents.size()) ) {
-                targetInstallName = dependents[bindTarget.libOrdinal - 1];
-            } else {
-                dylibOptimizedSection.unoptimizedOffsets.insert(sourceSectionOffset);
-                continue;
-            }
-
-            // find if bind target is really in another dylib or is a function variant
-            CString betterDylib = getActualSymbolImplDylib(bindTarget.symbolName, targetInstallName, installNameToDylibMap, targetIsFunctionVariant, functionVariantIndex);
-            if ( !betterDylib.empty() && (betterDylib != targetInstallName) ) {
-                targetInstallName = betterDylib.c_str();
-                //    fprintf(stderr, "%s found in %s instead of %s\n", bindTarget.symbolName, betterDylib.c_str(), targetInstallName);
-            }
-
-            if ( targetIsFunctionVariant )
-                targetDylib = installNameToDylibMap.at(targetInstallName);
-
-            MachOFile::PointerMetaData pmd(fixup, chainedFixupFormat);
-            key = { bindTarget.symbolName, targetInstallName, pmd, bindTarget.weakImport, targetIsFunctionVariant };
-        }
+            dylibOptimizedSection.unoptimizedOffsets.insert(sourceSectionOffset);
+            continue;
+        }
+
+        // We don't support addends right now.  But hopefully GOTs don't need them anyway
+        if ( addend != 0 )
+            continue;
+
+        const mach_o::Fixups::BindTargetInfo& bindTarget = bindTargets[bindOrdinal];
+
+        // TODO: Weak GOTs.  See rdar://86510941
+        const char* targetInstallName = nullptr;
+        if ( (bindTarget.libOrdinal > 0) && ((unsigned)bindTarget.libOrdinal <= dependents.size()) ) {
+            targetInstallName = dependents[bindTarget.libOrdinal - 1];
+        } else {
+            dylibOptimizedSection.unoptimizedOffsets.insert(sourceSectionOffset);
+            continue;
+        }
+
+        MachOFile::PointerMetaData pmd(fixup, chainedFixupFormat);
+
+        typedef CoalescedGOTSection::GOTKey Key;
+        Key key = { bindTarget.symbolName, targetInstallName, pmd, bindTarget.weakImport };
 
         int cacheSectionOffset = (int)(cacheGotSection->gotTargetsToOffsets.size() * pointerSize);
         auto itAndInserted = cacheGotSection->gotTargetsToOffsets.insert({ key, cacheSectionOffset });
@@ -4351,7 +3926,7 @@
             if (log) {
                 uint64_t gotOffset = ((uint64_t)pos - (uint64_t)content) - pointerSize;
                 printf("%s[%lld]: %s -> (%s, %s)\n",
-                       sectionName.data(), gotOffset, dylib->inputHdr->installName(),
+                       sectionName.data(), gotOffset, mf->installName(),
                        key.targetDylibName.data(), key.targetSymbolName.data());
             }
         } else {
@@ -4362,16 +3937,12 @@
 
         // Now keep track of this offset in our source dylib as pointing to this offset
         offsetMap[sourceSectionOffset] = cacheSectionOffset;
-
-        // store function-variant index in other map
-        if ( targetIsFunctionVariant )
-            cacheGotSection->functionVariantIndexes[key] = { targetDylib->cacheIndex, functionVariantIndex };
     }
 
     // Record which segment/section we just visited
-    uint32_t segmentIndex = gotSectionInfo->second.segIndex;
+    uint32_t segmentIndex = gotSectionInfo->segInfo.segIndex;
     dylibOptimizedSection.segmentIndex = segmentIndex;
-    dylibOptimizedSection.sectionVMOffsetInSegment = VMOffset(gotSectionInfo->second.address - gotSectionInfo->first.vmaddr);
+    dylibOptimizedSection.sectionVMOffsetInSegment = VMOffset(gotSectionInfo->sectAddr - gotSectionInfo->segInfo.vmAddr);
 }
 
 // This runs after we've assigned Chunk's to SubCache's, but before we've actually
@@ -4390,12 +3961,9 @@
 
     // DylibSegmentChunk's don't have a pointer to their cache dylib.  Make a map for them
     std::unordered_map<const InputFile*, CacheDylib*> fileToDylibMap;
-    std::unordered_map<std::string_view, CacheDylib*> installNameToDylibMap;
     fileToDylibMap.reserve(this->cacheDylibs.size());
-    for ( CacheDylib& dylib : this->cacheDylibs ) {
+    for ( CacheDylib& dylib : this->cacheDylibs )
         fileToDylibMap[dylib.inputFile] = &dylib;
-        installNameToDylibMap[dylib.installName] = &dylib;
-    }
 
     for ( SubCache& subCache : this->subCaches ) {
         // Find the DATA_CONST/AUTH_CONST in each SubCache, if it has any
@@ -4485,7 +4053,7 @@
                 dylibUniquedGOTs->subCacheSection = subCacheUniquedGOTs;
                 dylibOptimizedSections.push_back(dylibUniquedGOTs);
 
-                parseGOTs(dylib, segmentChunk, segmentName, sectionName, installNameToDylibMap, *dylibUniquedGOTs);
+                parseGOTs(dylib, segmentChunk, segmentName, sectionName, *dylibUniquedGOTs);
             }
 
             if ( subCacheUniquedGOTs->gotTargetsToOffsets.empty() )
@@ -4500,14 +4068,24 @@
             for ( const auto& keyAndValue : subCacheUniquedGOTs->gotTargetsToOffsets )
                 sortedKeys.push_back(keyAndValue.first);
 
-            std::sort(sortedKeys.begin(), sortedKeys.end(), [](const Key& a, const Key& b) {
-                // sort all function-variants together at end
-                if ( a.isFunctionVariant != b.isFunctionVariant )
-                    return b.isFunctionVariant;
-                // sort first by impl dylib name
+            std::sort(sortedKeys.begin(), sortedKeys.end(),
+                      [](const Key& a, const Key& b) {
+                // Put libSystem first, then all the /usr/lib/system dylibs
+                // That way any GOTs for re-exports from libsystem will be close to similar GOTs
+                bool isLibsystemA = a.targetDylibName.find("libSystem.B.dylib") != std::string_view::npos;
+                bool isLibsystemB = b.targetDylibName.find("libSystem.B.dylib") != std::string_view::npos;
+                if ( isLibsystemA != isLibsystemB )
+                    return isLibsystemA;
+
+                bool isLibsystemReexportA = a.targetDylibName.find("/usr/lib/system") != std::string_view::npos;
+                bool isLibsystemReexportB = b.targetDylibName.find("/usr/lib/system") != std::string_view::npos;
+                if ( isLibsystemReexportA != isLibsystemReexportB )
+                    return isLibsystemReexportA;
+
                 if ( a.targetDylibName != b.targetDylibName )
                     return (a.targetDylibName < b.targetDylibName);
-                // if install names are the same, sort by symbol name
+
+                // Install names are the same.  Sort by symbol name
                 return a.targetSymbolName < b.targetSymbolName;
             });
 
@@ -4549,7 +4127,7 @@
 
                     region->chunks.push_back(subCache.uniquedGOTs.get());
 
-                    subCache.uniquedGOTsOptimizer.regularGOTs.cacheChunk                    = subCache.uniquedGOTs.get();
+                    subCache.uniquedGOTsOptimizer.regularGOTs.cacheChunk = subCache.uniquedGOTs.get();
                     break;
                 case UniquedGOTKind::authGot:
                     subCache.uniquedAuthGOTs                    = std::make_unique<UniquedGOTsChunk>();
@@ -4558,7 +4136,7 @@
 
                     region->chunks.push_back(subCache.uniquedAuthGOTs.get());
 
-                    subCache.uniquedGOTsOptimizer.authGOTs.cacheChunk                    = subCache.uniquedAuthGOTs.get();
+                    subCache.uniquedGOTsOptimizer.authGOTs.cacheChunk = subCache.uniquedAuthGOTs.get();
                     break;
                 case UniquedGOTKind::authPtr:
                     subCache.uniquedAuthPtrs                    = std::make_unique<UniquedGOTsChunk>();
@@ -4567,7 +4145,7 @@
 
                     region->chunks.push_back(subCache.uniquedAuthPtrs.get());
 
-                    subCache.uniquedGOTsOptimizer.authPtrs.cacheChunk                    = subCache.uniquedAuthPtrs.get();
+                    subCache.uniquedGOTsOptimizer.authPtrs.cacheChunk = subCache.uniquedAuthPtrs.get();
                     break;
             }
 
@@ -4672,7 +4250,7 @@
         return false;
     };
 
-    auto readOnlySortOrder = [](const Chunk* a, const Chunk* b) -> bool {
+    auto linkeditSortOrder = [](const Chunk* a, const Chunk* b) -> bool {
         // Sort read-only segments before LINKEDIT
         if ( a->sortOrder() != b->sortOrder() )
             return a->sortOrder() < b->sortOrder();
@@ -4684,31 +4262,20 @@
 
     for ( SubCache& subCache : this->subCaches ) {
         for ( Region& region : subCache.regions ) {
-            switch ( region.kind ) {
-                case Region::Kind::text:
-                    std::stable_sort(region.chunks.begin(), region.chunks.end(), textSortOrder);
-                    break;
-                case Region::Kind::dataConst:
-                case Region::Kind::authConst:
-                    std::stable_sort(region.chunks.begin(), region.chunks.end(), dataConstSortOrder);
-                    break;
-                case Region::Kind::tproConst:
-                case Region::Kind::tproAuthConst:
-                    std::stable_sort(region.chunks.begin(), region.chunks.end(), tproConstSortOrder);
-                    break;
-                case Region::Kind::data:
-                case Region::Kind::auth:
-                    std::stable_sort(region.chunks.begin(), region.chunks.end(), dataSortOrder);
-                    break;
-                case Region::Kind::readOnly:
-                case Region::Kind::linkedit:
-                    std::stable_sort(region.chunks.begin(), region.chunks.end(), readOnlySortOrder);
-                    break;
-                case Region::Kind::unmapped:
-                case Region::Kind::dynamicConfig:
-                case Region::Kind::codeSignature:
-                case Region::Kind::numKinds:
-                    break;
+            if ( region.kind == Region::Kind::text ) {
+                std::stable_sort(region.chunks.begin(), region.chunks.end(), textSortOrder);
+            }
+            else if ( (region.kind == Region::Kind::data) || (region.kind == Region::Kind::auth) ) {
+                std::stable_sort(region.chunks.begin(), region.chunks.end(), dataSortOrder);
+            }
+            else if ( region.kind == Region::Kind::dataConst ) {
+                std::stable_sort(region.chunks.begin(), region.chunks.end(), dataConstSortOrder);
+            }
+            else if ( (region.kind == Region::Kind::tproConst) || (region.kind == Region::Kind::tproAuthConst) ) {
+                std::stable_sort(region.chunks.begin(), region.chunks.end(), tproConstSortOrder);
+            }
+            else if ( region.kind == Region::Kind::linkedit ) {
+                std::stable_sort(region.chunks.begin(), region.chunks.end(), linkeditSortOrder);
             }
         }
     }
@@ -5403,7 +4970,6 @@
         assert(!cacheDylib.segments.empty());
         assert(cacheDylib.segments[0].kind == cache_builder::DylibSegmentChunk::Kind::dylibText);
         cacheDylib.cacheMF          = (MachOFile*)cacheDylib.segments[0].subCacheBuffer;
-        cacheDylib.cacheHdr         = (const Header*)cacheDylib.segments[0].subCacheBuffer;
         cacheDylib.cacheLoadAddress = cacheDylib.segments[0].cacheVMAddress;
     }
 
@@ -5548,10 +5114,7 @@
                 case Chunk::Kind::linkeditExportTrie:
                     movedLinkedit.kind = MovedLinkedit::Kind::exportTrie;
                     break;
-                case Chunk::Kind::linkeditFunctionVariants:
-                    movedLinkedit.kind = MovedLinkedit::Kind::functionVariants;
-                    break;
-               default:
+                default:
                     assert(0);
                     break;
             }
@@ -5722,7 +5285,10 @@
                 patchableObjCClasses.insert(cacheDylib.adjustor->adjustVMAddr(inputVMAddr));
             });
 
-            cacheDylib.cacheHdr->forEachSingletonPatch(^(uint64_t runtimeOffset) {
+            // Note we have a diagnostic object here, but we don't care if it fails.  Then we'll
+            // just skip singleton patching on this dylib
+            Diagnostics diag;
+            cacheDylib.cacheMF->forEachSingletonPatch(diag, ^(MachOFile::SingletonPatchKind kind, uint64_t runtimeOffset) {
                 patchableCFObj2.insert(cacheDylib.cacheLoadAddress + VMOffset(runtimeOffset));
             });
         }
@@ -5754,184 +5320,6 @@
     return Error();
 }
 
-Error SharedCacheBuilder::emitPrewarmingData()
-{
-    // Skip everything if the JSON file is empty
-    if ( this->options.prewarmingOptimizations.empty() )
-        return Error::none();
-
-    using json::Node;
-    using json::NodeValueType;
-
-    Stats        stats(this->config);
-    Timer::Scope timedScope(this->config, "emitPrewarmingData time");
-
-    __block Diagnostics diag;
-    Node rootNode = json::readJSON(diag, this->options.prewarmingOptimizations.data(),
-                                   this->options.prewarmingOptimizations.size(),
-                                   false /* useJSON5 */);
-    if ( diag.hasError() )
-        return Error("%s", diag.errorMessageCStr());
-
-    std::unordered_map<std::string_view, const CacheDylib*> dylibMap;
-    for ( const CacheDylib& cacheDylib : cacheDylibs )
-        dylibMap[cacheDylib.installName] = &cacheDylib;
-
-    // Add install names too, just in case dylibs are moving
-    dylibMap.insert(this->dylibAliases.begin(), this->dylibAliases.end());
-
-    // Format is something like:
-    // [
-    //     {
-    //         "install_name": "..."
-    //         "locations": [
-    //             {
-    //                 "name": "symbol name",
-    //                 "offset": 0
-    //             }
-    //         ]
-    //     },
-    // ...
-    // ]
-    if ( rootNode.type != NodeValueType::Array )
-        return Error::none();
-
-    std::vector<dyld_prewarming_entry> prewarmingEntries;
-
-    const uint64_t PrewarmingPageSize = DYLD_CACHE_PREWARMING_DATA_PAGE_SIZE;
-    const uint64_t PrewarmingPageMask = ~(PrewarmingPageSize - 1);
-
-    // FIXME: Do this in parallel if needed, or even in CacheDylib when it goes parallel
-    for ( const Node& fileNode : rootNode.array ) {
-        // Find the install name and locations array
-        auto installNameIt = fileNode.map.find("install_name");
-        auto locationsIt = fileNode.map.find("locations");
-        if ( (installNameIt == fileNode.map.end()) || (locationsIt == fileNode.map.end()) )
-            continue;
-
-        const Node& installNameNode = installNameIt->second;
-        const Node& locationsNode = locationsIt->second;
-
-        // Find the cache dylib for this install name
-        const CacheDylib* cacheDylib = nullptr;
-        if ( auto it = dylibMap.find(installNameNode.value); it != dylibMap.end() )
-            cacheDylib = it->second;
-        else
-            continue;
-
-        // Get the exports trie
-        __block const uint8_t* trieStart = nullptr;
-        __block size_t trieSize = 0;
-        cacheDylib->inputMF->withFileLayout(diag, ^(const mach_o::Layout &layout) {
-            if ( layout.linkedit.exportsTrie.hasValue() ) {
-                trieStart = layout.linkedit.exportsTrie.buffer;
-                trieSize  = layout.linkedit.exportsTrie.bufferSize;
-            }
-        });
-        if ( diag.hasError() )
-            return Error("%s", diag.errorMessageCStr());
-
-        if ( trieStart == nullptr )
-            continue;
-
-        ExportsTrie exportsTrie(trieStart, trieSize);
-
-        // Lazily make a map of local symbols if we need it
-        __block std::unordered_map<std::string_view, uint64_t> localsMap;
-        auto populateLocals = ^() {
-            cacheDylib->inputMF->withFileLayout(diag, ^(const mach_o::Layout& layout) {
-                mach_o::SymbolTable symbolTable(layout);
-
-                symbolTable.forEachLocalSymbol(diag, ^(const char *symbolName, uint64_t n_value, uint8_t n_type,
-                                                       uint8_t n_sect, uint16_t n_desc, bool& stop) {
-                    if ( ((n_type & N_TYPE) == N_SECT) && ((n_type & N_STAB) == 0) ) {
-                        localsMap[symbolName] = (n_value - cacheDylib->inputLoadAddress.rawValue());
-                    }
-                });
-            });
-        };
-
-        // Walk all locations, looking them up in exports/locals
-        for ( const Node& locationNode : locationsNode.array ) {
-            auto nameIt = locationNode.map.find("name");
-            auto offsetIt = locationNode.map.find("offset");
-            if ( (nameIt == locationNode.map.end()) || (offsetIt == locationNode.map.end()) )
-                continue;
-
-            uint64_t offset = parseRequiredInt(diag, offsetIt->second);
-            if ( diag.hasError() )
-                return Error("%s", diag.errorMessageCStr());
-
-            // Check for an export first, then a local
-            uint64_t implOffset = 0;
-            mach_o::Symbol symbol;
-            if ( exportsTrie.hasExportedSymbol(nameIt->second.value.c_str(), symbol) ) {
-                if ( !symbol.isRegular(implOffset) )
-                    continue;
-            } else {
-                if ( localsMap.empty() ) {
-                    populateLocals();
-                    if ( diag.hasError() )
-                        return Error("%s", diag.errorMessageCStr());
-                }
-
-                if ( auto localsIt = localsMap.find(nameIt->second.value); localsIt != localsMap.end() )
-                    implOffset = localsIt->second;
-            }
-
-            InputDylibVMAddress inputVMAddr(cacheDylib->inputLoadAddress + VMOffset(implOffset));
-            CacheVMAddress cacheVMAddr = cacheDylib->adjustor->adjustVMAddr(inputVMAddr);
-            cacheVMAddr += VMOffset(offset);
-
-            VMOffset cacheVMOffset = cacheVMAddr - this->config.layout.cacheBaseAddress;
-
-            prewarmingEntries.push_back({ cacheVMOffset.rawValue() & PrewarmingPageMask, 1 });
-        }
-    }
-
-    PrewarmingOptimizer& opt = this->prewarmingOptimizer;
-    dyld_prewarming_header* header = (dyld_prewarming_header*)opt.prewarmingChunk->subCacheBuffer;
-    const void* bufferEnd = opt.prewarmingChunk->subCacheBuffer + opt.prewarmingChunk->subCacheFileSize.rawValue();
-
-    if ( prewarmingEntries.empty() ) {
-        header->version = 1;
-        header->count = 0;
-        return Error::none();
-    }
-
-    // Sort by ascending VM addresses
-    std::sort(prewarmingEntries.begin(), prewarmingEntries.end(),
-              [](const dyld_prewarming_entry& a, const dyld_prewarming_entry& b) {
-        return a.cacheVMOffset < b.cacheVMOffset;
-    });
-
-    // Combine adjacent entries
-    std::vector<dyld_prewarming_entry> combinedEntries;
-    combinedEntries.push_back(prewarmingEntries.front());
-    for ( const dyld_prewarming_entry& entry : std::span(prewarmingEntries).subspan(1) ) {
-        dyld_prewarming_entry& last = combinedEntries.back();
-        if ( entry.cacheVMOffset == last.cacheVMOffset )
-            continue;
-        if ( entry.cacheVMOffset == (last.cacheVMOffset + PrewarmingPageSize) ) {
-            ++last.numPages;
-        } else {
-            combinedEntries.push_back(entry);
-        }
-    }
-
-    // write the results
-    dyld_prewarming_entry* firstOutputEntry = &header->entries[0];
-    dyld_prewarming_entry* lastOutputEntry = &header->entries[combinedEntries.size()];
-    if ( lastOutputEntry > bufferEnd )
-        return Error("overflow in prewarming optimizer (%p vs %p)", lastOutputEntry, bufferEnd);
-
-    header->version = 1;
-    header->count = (uint32_t)combinedEntries.size();
-    memcpy(firstOutputEntry, combinedEntries.data(), sizeof(dyld_prewarming_entry) * header->count);
-
-    return Error();
-}
-
 // dyld4 needs a fake "main.exe" to set up the state.
 // On macOS this *has* to come from an actual executable, as choosing a zippered
 // dylib may incorrectly lead to setting up the ProcessConfig as iOSMac.
@@ -5958,7 +5346,7 @@
         }
     } else {
         const char* binPath = "/usr/bin/";
-        if ( options.platform == Platform::driverKit )
+        if ( options.platform == dyld3::Platform::driverKit )
             binPath = "/System/Library/DriverExtensions/";
         for ( const InputFile* exeFile : executableFiles ) {
             if ( startsWith(exeFile->path, binPath) )
@@ -6016,8 +5404,8 @@
             }
 
             // The cache segments don't have the permissions.  Get that from the load commands
-            cacheDylib.cacheHdr->forEachSegment(^(const Header::SegmentInfo& info, bool& stop) {
-                segments[info.segmentIndex].protections = info.initProt;
+            cacheDylib.cacheMF->forEachSegment(^(const MachOFile::SegmentInfo& info, bool& stop) {
+                segments[info.segIndex].protections = info.protections;
             });
             this->dylibSegmentLayout.push_back(std::move(segments));
         }
@@ -6044,11 +5432,6 @@
                         linkeditLayout.exportsTrie.entryCount  = 0; // Not needed here
                         linkeditLayout.exportsTrie.hasLinkedit = true;
                         break;
-                    case MovedLinkedit::Kind::functionVariants:
-                        linkeditLayout.functionVariants.buffer      = kindAndLinkdit.second.cacheLocation;
-                        linkeditLayout.functionVariants.bufferSize  = (uint32_t)kindAndLinkdit.second.dataSize.rawValue();
-                        linkeditLayout.functionVariants.hasLinkedit = true;
-                        break;
                     case MovedLinkedit::Kind::numKinds:
                         // This should never happen
                         assert(false);
@@ -6074,21 +5457,21 @@
         this->executableSegmentLayout.reserve(executableFiles.size());
         for ( const InputFile* executableFile : executableFiles ) {
             __block std::vector<mach_o::SegmentLayout> segments;
-            ((const Header*)executableFile->mf)->forEachSegment(^(const Header::SegmentInfo& info, bool& stop) {
+            executableFile->mf->forEachSegment(^(const MachOFile::SegmentInfo& info, bool& stop) {
                 // Note file layout here, not VM layout
                 uint8_t*              segmentBuffer = (uint8_t*)executableFile->mf + info.fileOffset;
                 mach_o::SegmentLayout segment;
-                segment.vmAddr      = info.vmaddr;
-                segment.vmSize      = info.vmsize;
+                segment.vmAddr      = info.vmAddr;
+                segment.vmSize      = info.vmSize;
                 segment.fileOffset  = info.fileOffset;
                 segment.fileSize    = info.fileSize;
                 segment.buffer      = segmentBuffer;
-                segment.protections = info.initProt;
+                segment.protections = info.protections;
 
                 segment.kind        = mach_o::SegmentLayout::Kind::unknown;
-                if ( info.segmentName == "__TEXT" ) {
+                if ( !strcmp(info.segName, "__TEXT") ) {
                     segment.kind    = mach_o::SegmentLayout::Kind::text;
-                } else if ( info.segmentName == "__LINKEDIT" ) {
+                } else if ( !strcmp(info.segName, "__LINKEDIT") ) {
                     segment.kind    = mach_o::SegmentLayout::Kind::linkedit;
                 }
 
@@ -6180,7 +5563,7 @@
         }
     }
 
-    Loader::LoadOptions::Finder loaderFinder = ^(Diagnostics& loadDiag, Platform, const char* loadPath, const dyld4::Loader::LoadOptions& options) {
+    Loader::LoadOptions::Finder loaderFinder = ^(Diagnostics& loadDiag, dyld3::Platform, const char* loadPath, const dyld4::Loader::LoadOptions& options) {
         auto pos = loadersMap.find(loadPath);
         if ( pos != loadersMap.end() ) {
             return (const Loader*)pos->second;
@@ -6329,14 +5712,14 @@
             __block InputDylibVMAddress inputOptPtrsVMAddress;
             __block uint64_t            sectionSize = 0;
             __block bool                found       = false;
-            cacheDylib->inputHdr->forEachSection(^(const Header::SectionInfo& sectInfo, bool& stop) {
-                if ( !sectInfo.segmentName.starts_with("__DATA") && !sectInfo.segmentName.starts_with("__AUTH") )
+            cacheDylib->inputMF->forEachSection(^(const dyld3::MachOAnalyzer::SectionInfo& sectInfo, bool malformedSectionRange, bool& stop) {
+                if ( (strncmp(sectInfo.segInfo.segName, "__DATA", 6) != 0) && (strncmp(sectInfo.segInfo.segName, "__AUTH", 6) != 0) )
                     return;
-                if ( sectInfo.sectionName != "__objc_opt_ptrs" )
+                if ( strcmp(sectInfo.sectName, "__objc_opt_ptrs") != 0 )
                     return;
 
-                inputOptPtrsVMAddress = InputDylibVMAddress(sectInfo.address);
-                sectionSize           = sectInfo.size;
+                inputOptPtrsVMAddress = InputDylibVMAddress(sectInfo.sectAddr);
+                sectionSize           = sectInfo.sectSize;
 
                 found = true;
                 stop  = true;
@@ -6353,7 +5736,7 @@
             //     T protocolClass;
             // };
             // typedef struct objc_opt_pointerlist_tt<uintptr_t> objc_opt_pointerlist_t;
-            if ( sectionSize < cacheDylib->inputHdr->pointerSize() ) {
+            if ( sectionSize < cacheDylib->inputMF->pointerSize() ) {
                 return Error("libobjc's pointer list section is too small (metadata not optimized)");
             }
 
@@ -6447,8 +5830,8 @@
         }
 
         // Assume last segment file size is the overall file size
-        __block uint32_t fileSize = 0;
-        ((const Header*)inputFile->mf)->forEachSegment(^(const Header::SegmentInfo& info, bool& stop) {
+        __block uint64_t fileSize = 0;
+        inputFile->mf->forEachSegment(^(const MachOFile::SegmentInfo& info, bool& stop) {
             fileSize = std::max(fileSize, info.fileOffset + info.fileSize);
         });
         otherMapping[inputFile->path] = { inputFile->mf, fileSize };
@@ -6500,9 +5883,7 @@
         processConfig.dyldCache.dylibsExpectedOnDisk = !this->options.dylibsRemovedFromDisk;
         processConfig.dyldCache.development = isDevelopmentSharedCache(this->options);
 
-        // Disable objc optimizations from EK shared cache
-        bool emitObjcOpts = !this->options.platform.isExclaveKit();
-        if ( !this->objcOptimizer.objcDylibs.empty() && emitObjcOpts ) {
+        if ( !this->objcOptimizer.objcDylibs.empty() ) {
             processConfig.dyldCache.objcClassHashTable = (const objc::ClassHashTable*)this->objcClassOptimizer.classHashTableChunk->subCacheBuffer;
             processConfig.dyldCache.objcSelectorHashTable = (const objc::SelectorHashTable*)this->objcSelectorOptimizer.selectorHashTableChunk->subCacheBuffer;
             processConfig.dyldCache.objcProtocolHashTable = (const objc::ProtocolHashTable*)this->objcProtocolOptimizer.protocolHashTableChunk->subCacheBuffer;
@@ -6513,9 +5894,9 @@
             processConfig.dyldCache.unslidLoadAddress = config.layout.cacheBaseAddress.rawValue();
         }
 
-        Loader::LoadOptions::Finder loaderFinder = ^(Diagnostics& diag, Platform plat, const char* loadPath, const dyld4::Loader::LoadOptions& loadOptions) {
+        Loader::LoadOptions::Finder loaderFinder = ^(Diagnostics& diag, dyld3::Platform plat, const char* loadPath, const dyld4::Loader::LoadOptions& loadOptions) {
             // when building macOS cache, there may be some incorrect catalyst paths
-            if ( (plat == Platform::macCatalyst) && (strncmp(loadPath, "/System/iOSSupport/", 19) != 0) ) {
+            if ( (plat == dyld3::Platform::iOSMac) && (strncmp(loadPath, "/System/iOSSupport/", 19) != 0) ) {
                 char altPath[PATH_MAX];
                 strlcpy(altPath, "/System/iOSSupport", PATH_MAX);
                 strlcat(altPath, loadPath, PATH_MAX);
@@ -6596,6 +5977,7 @@
     });
 
     assert(!err.hasError());
+
     std::map<std::string_view, const dyld4::PrebuiltLoaderSet*> prebuiltsMap;
     uint64_t prebuiltsSpace = 0;
     for ( uint64_t i = 0; i != this->exeInputFiles.size(); ++i ) {
@@ -6605,7 +5987,7 @@
             continue;
 
         prebuiltsMap[exeFile->path.c_str()] = loaderSet;
-        prebuiltsSpace += alignTo(loaderSet->size(), alignof(dyld4::PrebuiltLoaderSet));
+        prebuiltsSpace += alignTo(loaderSet->size(), 8);
     }
 
     const PrebuiltLoaderChunk* loaderChunk = this->prebuiltLoaderBuilder.executablesLoaderChunk;
@@ -6665,7 +6047,7 @@
 
         size_t size = pbls->size();
         ::memcpy(poolBase + currentPoolOffset, pbls, size);
-        currentPoolOffset += alignTo(size, alignof(dyld4::PrebuiltLoaderSet));
+        currentPoolOffset += alignTo(size, 8);
     }
 
     const CacheTrieChunk* trieChunk = this->prebuiltLoaderBuilder.executableTrieChunk;
@@ -7109,25 +6491,26 @@
         if ( cacheDylib.installName != "/usr/lib/libobjc.A.dylib" )
             continue;
 
-        cacheDylib.cacheHdr->forEachSection(^(const Header::SegmentInfo &segInfo, const Header::SectionInfo &sectInfo, bool &stop) {
-            if ( sectInfo.segmentName != "__TEXT" )
+        cacheDylib.cacheMF->forEachSection(^(const dyld3::MachOFile::SectionInfo &sectInfo,
+                                             bool malformedSectionRange, bool &stop) {
+            if (strcmp(sectInfo.segInfo.segName, "__TEXT") != 0)
                 return;
-            if ( sectInfo.sectionName != "__objc_opt_ro" )
+            if (strcmp(sectInfo.sectName, "__objc_opt_ro") != 0)
                 return;
 
             // Find the buffer for the section
             stop = true;
 
-            const DylibSegmentChunk& segment = cacheDylib.segments[sectInfo.segIndex];
-
-            VMAddress sectionVMAddr(sectInfo.address);
-            VMAddress segmentVMAddr(segInfo.vmaddr);
+            const DylibSegmentChunk& segment = cacheDylib.segments[sectInfo.segInfo.segIndex];
+
+            VMAddress sectionVMAddr(sectInfo.sectAddr);
+            VMAddress segmentVMAddr(sectInfo.segInfo.vmAddr);
             VMOffset sectionOffsetInSegment = sectionVMAddr - segmentVMAddr;
             uint8_t* sectionBuffer = segment.subCacheBuffer + sectionOffsetInSegment.rawValue();
 
             // All fields in the old header are offsets from the header.  This is how much to
             // shift them by
-            uint64_t headerCacheOffset = sectInfo.address - this->config.layout.cacheBaseAddress.rawValue();
+            uint64_t headerCacheOffset = sectInfo.sectAddr - this->config.layout.cacheBaseAddress.rawValue();
 
             // Found the section, now write the content
             objc_opt::objc_opt_t* libROHeader = (objc_opt::objc_opt_t *)sectionBuffer;
@@ -7173,12 +6556,22 @@
     }
 }
 
+// Struct matching dyld4::LibdyldDyld4Section to be used with a variable pointer size.
+// This is so we can use it in the shared cache builder, which is always
+// 64-bit but can emit 32-bit structs
+template <typename P>
+struct FixedSizeLibdyldDyld4Section {
+    P apis;
+    P allImageInfos;
+    P defaultVars[5];
+    P dyldLookupFuncAddr;
+    P tlv_get_addrAddr;
+};
+
+static_assert(sizeof(FixedSizeLibdyldDyld4Section<intptr_t>) == sizeof(dyld4::LibdyldDyld4Section));
+
 void SharedCacheBuilder::optimizeTLVs()
 {
-    // driverkit does not support thread-locals, all other platforms do
-    if ( options.platform == Platform::driverKit )
-        return;
-
     Stats        stats(this->config);
     Timer::Scope timedScope(this->config, "optimizeTLVs time");
 
@@ -7205,20 +6598,61 @@
         return;
     }
 
-    // Find _tlv_get_addr function in libdyld.dylib
-    Image libdyldImg((void*)libdyldDylib->inputHdr, 0x40000, Image::MappingKind::wholeSliceMapped);
-
-    Symbol tlvBootstrapSymbol;
-    if ( !libdyldImg.exportsTrie().hasExportedSymbol("__tlv_bootstrap", tlvBootstrapSymbol) ) {
-        this->warning("Could not find '_tlv_get_addr' in libdyld");
+    // Find the tlv_get_addrAddr from inside the __dyld4 section
+    __block CacheVMAddress getAddrVMAddr;
+    __block bool foundTLVGetAddr = false;
+    libdyldDylib->cacheMF->forEachSection(^(const MachOFile::SectionInfo &sectInfo,
+                                            bool malformedSectionRange, bool &stop) {
+        if ( strcmp(sectInfo.sectName, "__dyld4") != 0 )
+            return;
+
+        if ( (strncmp(sectInfo.segInfo.segName, "__DATA", 6) != 0)
+            && (strncmp(sectInfo.segInfo.segName, "__AUTH", 6) != 0)
+            && (strncmp(sectInfo.segInfo.segName, "__TPRO_CONST", 12) != 0))
+            return;
+
+        // Found the section we need.  Now to check if its valid
+        stop = true;
+
+        const DylibSegmentChunk& segment = libdyldDylib->segments[sectInfo.segInfo.segIndex];
+
+        VMAddress sectionVMAddr(sectInfo.sectAddr);
+        VMAddress segmentVMAddr(sectInfo.segInfo.vmAddr);
+        VMOffset sectionOffsetInSegment = sectionVMAddr - segmentVMAddr;
+        uint8_t* sectionBuffer = segment.subCacheBuffer + sectionOffsetInSegment.rawValue();
+
+
+        if ( this->config.layout.is64 ) {
+            typedef FixedSizeLibdyldDyld4Section<uint64_t> dyld4_section_t;
+            if ( sectInfo.sectSize < sizeof(dyld4_section_t) ) {
+                // Old libdyld without the field we need
+                return;
+            }
+
+            const dyld4_section_t* dyldSection = (dyld4_section_t*)sectionBuffer;
+            CacheVMAddress cacheBaseAddress = this->config.layout.cacheBaseAddress;
+            getAddrVMAddr = Fixup::Cache64::getCacheVMAddressFromLocation(cacheBaseAddress,
+                                                                          &dyldSection->tlv_get_addrAddr);
+        } else {
+            typedef FixedSizeLibdyldDyld4Section<uint32_t> dyld4_section_t;
+            if ( sectInfo.sectSize < sizeof(dyld4_section_t) ) {
+                // Old libdyld without the field we need
+                return;
+            }
+
+            const dyld4_section_t* dyldSection = (dyld4_section_t*)sectionBuffer;
+            CacheVMAddress cacheBaseAddress = this->config.layout.cacheBaseAddress;
+            getAddrVMAddr = Fixup::Cache32::getCacheVMAddressFromLocation(cacheBaseAddress,
+                                                                          &dyldSection->tlv_get_addrAddr);
+        }
+
+        foundTLVGetAddr = true;
+    });
+
+    if ( !foundTLVGetAddr ) {
+        this->warning("Could not find tlv_get_addr (TLVs not optimized)");
         return;
     }
-    // NOTE:  magic here:
-    // To cleanly error of if TLVs are not set up, the on-disk thunks bind to _tlv_bootstrap, which aborts in invoked.
-    // The thunks when setup are changed to point to _tlv_get_addr, which is not an exported symbol.  Therefore
-    // the cache builder has no way to find it. The fix/hack is that _tlv_bootstrap and _tlv_get_addr are written
-    // in assembly and always 8 bytes apart.
-    CacheVMAddress getAddrVMAddr(libdyldDylib->cacheLoadAddress.rawValue() + tlvBootstrapSymbol.implOffset() + 8);
 
     // We read the value for this symbol to know the first key we can allocate for TLVs
     // We then have to stop optimizing if and when we reach "end", that's the
@@ -7270,7 +6704,7 @@
             return;
         }
 
-        if ( !cacheDylib.cacheHdr->hasThreadLocalVariables() )
+        if ( !cacheDylib.cacheMF->hasThreadLocalVariables() )
             continue;
 
         // Get the next available key (one key per dylib)
@@ -7287,117 +6721,69 @@
             return;
         }
 
-        // find initial content for all thread locals in this dylib
-        __block bool        initialContentNonZero = false;
-        __block uint64_t    initialContentAddr    = 0;
-        __block size_t      initialContentSize    = 0;
-        cacheDylib.cacheHdr->forEachSection(^(const Header::SectionInfo& sectInfo, bool& stop) {
-            switch ( sectInfo.flags & SECTION_TYPE ) {
-                case S_THREAD_LOCAL_REGULAR:
-                    initialContentNonZero = true;
-                    [[clang::fallthrough]];
-                case S_THREAD_LOCAL_ZEROFILL:
-                    if ( initialContentSize == 0 ) {
-                        // first of N contiguous TLV template sections, record as if this was only section
-                        initialContentAddr = sectInfo.address;
-                        initialContentSize = sectInfo.size;
-                    }
-                    else {
-                        // non-first of N contiguous TLV template sections, accumlate values
-                        initialContentSize = sectInfo.address + sectInfo.size - initialContentAddr;
-                    }
-                    break;
-            }
-        });
-
-        cacheDylib.cacheHdr->forEachSection(^(const Header::SegmentInfo &segInfo, const Header::SectionInfo& sectInfo, bool& stop) {
-            if ( (sectInfo.flags & SECTION_TYPE) != S_THREAD_LOCAL_VARIABLES )
+        cacheDylib.cacheMF->forEachSection(^(const MachOFile::SectionInfo& sectInfo,
+                                             bool malformedSectionRange, bool& stop) {
+            if ( (sectInfo.sectFlags & SECTION_TYPE) != S_THREAD_LOCAL_VARIABLES )
                 return;
 
-            DylibSegmentChunk& segment = cacheDylib.segments[sectInfo.segIndex];
-
-            VMAddress sectionVMAddr(sectInfo.address);
-            VMAddress segmentVMAddr(segInfo.vmaddr);
+            DylibSegmentChunk& segment = cacheDylib.segments[sectInfo.segInfo.segIndex];
+
+            VMAddress sectionVMAddr(sectInfo.sectAddr);
+            VMAddress segmentVMAddr(sectInfo.segInfo.vmAddr);
             VMOffset sectionOffsetInSegment = sectionVMAddr - segmentVMAddr;
             uint8_t* sectionBuffer = segment.subCacheBuffer + sectionOffsetInSegment.rawValue();
 
             if ( this->config.layout.is64 ) {
-                struct tlv_disk_thunk64_t
+                struct tlv_thunk_t
                 {
-                    uint64_t func;
+                    uint64_t thunk;
                     uint64_t key;
                     uint64_t offset;
                 };
 
-                uint32_t            count       = (uint32_t)(sectInfo.size / sizeof(tlv_disk_thunk64_t));
-                tlv_disk_thunk64_t* thunkBuffer = (tlv_disk_thunk64_t*)sectionBuffer;
-                for ( uint32_t i = 0; i < count; ++i ) {
-                    size_t                                      offset   = thunkBuffer[i].offset; // only value needed from disk format
-                    dyld::ThreadLocalVariables::TLV_Thunkv2&   newThunk = *((dyld::ThreadLocalVariables::TLV_Thunkv2*)&thunkBuffer[i]);
-
-                    // Reset the fields using TLV_Thunkv2 format
-                    newThunk.key                 = key;
-                    newThunk.offset              = (uint32_t)offset;
-                    newThunk.initialContentSize  = (uint32_t)initialContentSize;
-                    newThunk.initialContentDelta = 0;
-                    if ( initialContentNonZero ) {
-                        uint64_t newThunkDeltaFieldAddr = (sectInfo.address + i*sizeof(tlv_disk_thunk64_t) + offsetof(dyld::ThreadLocalVariables::TLV_Thunkv2,initialContentDelta));
-                        newThunk.initialContentDelta = (int32_t)(initialContentAddr - newThunkDeltaFieldAddr);
-                    }
+                uint32_t count = (uint32_t)(sectInfo.sectSize / sizeof(tlv_thunk_t));
+                tlv_thunk_t* thunkBuffer = (tlv_thunk_t*)sectionBuffer;
+                for ( uint32_t i = 0; i != count; ++i ) {
+                    tlv_thunk_t& tlvThunk = thunkBuffer[i];
+
+                    // Set the key to the next available key
+                    tlvThunk.key = key;
 
                     // Set the thunk to tlv_get_addr()
-                    uint8_t  high8          = 0;
-                    uint16_t authDiversity  = 0;
-                    bool     authHasAddrDiv = false;
-                    uint8_t  authKey        = ptrauth_key_asia;
-                    bool     isAuth         = this->config.layout.hasAuthRegion;
-                    Fixup::Cache64::setLocation(this->config.layout.cacheBaseAddress, &newThunk.func,
+                    uint8_t high8 = 0;
+                    uint16_t authDiversity = 0;
+                    bool authHasAddrDiv = false;
+                    uint8_t authKey = ptrauth_key_asia;
+                    bool isAuth = this->config.layout.hasAuthRegion;
+                    Fixup::Cache64::setLocation(this->config.layout.cacheBaseAddress, &tlvThunk.thunk,
                                                 getAddrVMAddr, high8,
                                                 authDiversity, authHasAddrDiv, authKey, isAuth);
 
                     // Add to ASLR tracker
-                    segment.tracker.add(&newThunk.func);
+                    segment.tracker.add(&tlvThunk.thunk);
                 }
-            } 
-            else {
-                struct tlv_disk_thunk32_t
+            } else {
+                struct tlv_thunk_t
                 {
-                    uint32_t func;
+                    uint32_t thunk;
                     uint32_t key;
                     uint32_t offset;
                 };
-                struct tlv_cache_thunk32_t
-                {
-                    uint32_t     func;
-                    uint16_t     key;
-                    uint16_t     offset;
-                    int32_t      machHeaderDelta; // if < 0, content is found by walking load commands. If > 0, then it is size and content is all zeros
-                };
-                static_assert(sizeof(tlv_disk_thunk32_t) == sizeof(tlv_cache_thunk32_t));
-                uint32_t            loadAddr    = (uint32_t)(cacheDylib.cacheHdr->preferredLoadAddress());
-                uint32_t            count       = (uint32_t)(sectInfo.size / sizeof(tlv_disk_thunk32_t));
-                tlv_disk_thunk32_t* thunkBuffer = (tlv_disk_thunk32_t*)sectionBuffer;
-                for ( uint32_t i = 0; i < count; ++i ) {
-                    uint32_t               offset   = thunkBuffer[i].offset; // only value needed from disk format
-                    tlv_cache_thunk32_t&   newThunk = *((tlv_cache_thunk32_t*)&thunkBuffer[i]);
-
-                    if ( offset > 0xFFFF )
-                        this->warning("thread-local too large (%u max 65535) in %s", offset, cacheDylib.inputFile->path.c_str());
-
-                    // Reset the fields using TLV_Thunkv2 format
-                    newThunk.key                 = (uint16_t)key;
-                    newThunk.offset              = (uint16_t)offset;    // FIXME: error if offset > 0xFFFF
-                    newThunk.machHeaderDelta     = (uint32_t)initialContentSize;
-                    if ( initialContentNonZero ) {
-                        uint64_t newThunkDeltaFieldAddr = (sectInfo.address + i*sizeof(tlv_disk_thunk32_t) + offsetof(tlv_cache_thunk32_t,machHeaderDelta));
-                        newThunk.machHeaderDelta = (int32_t)(loadAddr - newThunkDeltaFieldAddr);
-                    }
+
+                uint32_t count = (uint32_t)(sectInfo.sectSize / sizeof(tlv_thunk_t));
+                tlv_thunk_t* thunkBuffer = (tlv_thunk_t*)sectionBuffer;
+                for ( uint32_t i = 0; i != count; ++i ) {
+                    tlv_thunk_t& tlvThunk = thunkBuffer[i];
+
+                    // Set the key to the next available key
+                    tlvThunk.key = key;
 
                     // Set the thunk to tlv_get_addr()
-                    Fixup::Cache32::setLocation(this->config.layout.cacheBaseAddress, &newThunk.func, getAddrVMAddr);
+                    Fixup::Cache32::setLocation(this->config.layout.cacheBaseAddress, &tlvThunk.thunk,
+                                                getAddrVMAddr);
 
                     // Add to ASLR tracker
-                    segment.tracker.add(&newThunk.func);
+                    segment.tracker.add(&tlvThunk.thunk);
                 }
             }
         });
@@ -7620,7 +7006,7 @@
         objc_visitor::Visitor& objcVisitor = objcVisitors[dylibObjCIndex];
 
         if ( log ) {
-            printf("  at 0x%llx in %s\n", protocolVMAddr, objcVisitor.hdr()->installName());
+            printf("  at 0x%llx in %s\n", protocolVMAddr, objcVisitor.mf()->installName());
         }
 
         __block bool foundProtocol = false;
@@ -7778,7 +7164,7 @@
                         error = Error("Superclass of class '%s' is weak-import"
                                       "and missing.  Referenced in %s",
                                       objcClass.getName(objcVisitor),
-                                      objcVisitor.hdr()->installName());
+                                      objcVisitor.mf()->installName());
                     stopClass = true;
                     this->objcOptimizer.foundMissingWeakSuperclass = true;
                 }
@@ -7811,7 +7197,7 @@
                 classMap[classVMAddr] = (uint32_t)classInfos.size();
 
             if ( log ) {
-                printf("%s: [0x%08llx] %s%s\n", objcVisitor.hdr()->installName(), classVMAddr.rawValue(),
+                printf("%s: [0x%08llx] %s%s\n", objcVisitor.mf()->installName(), classVMAddr.rawValue(),
                        objcClass.getName(objcVisitor), objcClass.isMetaClass ? " (meta)" : "");
             }
 
@@ -8297,7 +7683,7 @@
     size_t objcIndex = 0;
     for (size_t cacheIndex = 0; cacheIndex < this->cacheDylibs.size(); cacheIndex++) {
         CacheDylib& cacheDylib = this->cacheDylibs[cacheIndex];
-        if ( !cacheDylib.inputHdr->hasObjC() )
+        if ( !cacheDylib.inputMF->hasObjC() )
             continue;
 
         this->objcCategoryOptimizer.preAttachedDylibs.insert(objcIndex);
@@ -8355,86 +7741,12 @@
                          this->objcOptimizer.headerInfoReadWriteChunk->subCacheBuffer,
                          this->objcOptimizer.headerInfoReadOnlyChunk->cacheVMAddress,
                          swiftPrespecializedDylib,
-                         this->swiftOptimizer);
+                         this->swiftProtocolConformanceOptimizer);
     if ( diag.hasError() )
         return Error("Couldn't build Swift protocol opts because: %s", diag.errorMessageCStr());
 
     return Error();
 }
-
-static void getFunctionVariantTable(const CacheDylib& cacheDylib, uint64_t& vmAddr, uint64_t& vmSize)
-{
-    vmAddr = 0;
-    vmSize = 0;
-    for ( const LinkeditDataChunk& chunk : cacheDylib.linkeditChunks ) {
-        if ( chunk.isFunctionVariantsTable() ) {
-            vmAddr = chunk.cacheVMAddress.rawValue();
-            vmSize = chunk.cacheVMSize.rawValue();
-        }
-    }
-}
-
-void SharedCacheBuilder::emitFunctionVariants()
-{
-    // find uniqued GOT slots in each subcache that point to function variants
-    for ( SubCache& subCache : this->subCaches ) {
-        // look at regular GOTS
-        for (const auto& fv : subCache.uniquedGOTsOptimizer.regularGOTs.functionVariantIndexes) {
-            uint32_t offsetInGOTSection = subCache.uniquedGOTsOptimizer.regularGOTs.gotTargetsToOffsets.at(fv.first);
-            uint32_t targetDylibIndex   = fv.second.dylibIndex;
-            uint64_t fvTableVmAddr;
-            uint64_t fvTableVmSize;
-            getFunctionVariantTable(this->cacheDylibs[targetDylibIndex], fvTableVmAddr, fvTableVmSize);
-            dyld_cache_function_variant_entry entry;
-            entry.fixupLocVmAddr               = subCache.uniquedGOTsOptimizer.regularGOTs.cacheChunk->cacheVMAddress.rawValue() + offsetInGOTSection;
-            entry.functionVariantTableVmAddr   = fvTableVmAddr;
-            entry.functionVariantTableSizeDiv4 = fvTableVmSize/4;
-            entry.dylibHeaderVmAddr            = this->cacheDylibs[targetDylibIndex].cacheLoadAddress.rawValue();
-            entry.variantIndex                 = fv.second.variantIndex;
-            entry.pacAuth                      = false;
-            entry.pacAddress                   = 0;
-            entry.pacKey                       = 0;
-            entry.pacDiversity                 = 0;
-            entry.targetDylibIndex             = targetDylibIndex;
-            assert(entry.variantIndex == fv.second.variantIndex);
-            this->functionVariantsOptimizer.infos.push_back(entry);
-        }
-        // look at authGOTs
-        for (const auto& fv : subCache.uniquedGOTsOptimizer.authGOTs.functionVariantIndexes) {
-            uint32_t offsetInGOTSection = subCache.uniquedGOTsOptimizer.authGOTs.gotTargetsToOffsets.at(fv.first);
-            uint32_t targetDylibIndex   = fv.second.dylibIndex;
-            uint64_t fvTableVmAddr;
-            uint64_t fvTableVmSize;
-            getFunctionVariantTable(this->cacheDylibs[targetDylibIndex], fvTableVmAddr, fvTableVmSize);
-            dyld_cache_function_variant_entry entry;
-            entry.fixupLocVmAddr               = subCache.uniquedGOTsOptimizer.authGOTs.cacheChunk->cacheVMAddress.rawValue() + offsetInGOTSection;
-            entry.functionVariantTableVmAddr   = fvTableVmAddr;
-            entry.functionVariantTableSizeDiv4 = fvTableVmSize/4;
-            entry.dylibHeaderVmAddr            = this->cacheDylibs[targetDylibIndex].cacheLoadAddress.rawValue();
-            entry.variantIndex                 = fv.second.variantIndex;
-            entry.pacAuth                      = true;
-            entry.pacAddress                   = fv.first.pmd.usesAddrDiversity;
-            entry.pacKey                       = fv.first.pmd.key;
-            entry.pacDiversity                 = fv.first.pmd.diversity;
-            entry.targetDylibIndex             = targetDylibIndex;
-            assert(entry.variantIndex == fv.second.variantIndex);
-            this->functionVariantsOptimizer.infos.push_back(entry);
-        }
-    }
-
-    // make sure it fits in estimated size
-    size_t actualSize = offsetof(dyld_cache_function_variant_info, entries[this->functionVariantsOptimizer.infos.size()]);
-    assert(actualSize < this->functionVariantsOptimizer.fvInfoTotalByteSize);
-    this->functionVariantsOptimizer.fvInfoTotalByteSize = actualSize;
-    
-    // write table to LINKEDIT
-    dyld_cache_function_variant_info* table = (dyld_cache_function_variant_info*)(this->functionVariantsOptimizer.chunk->subCacheBuffer);
-    table->version = 1;
-    table->count   = (uint32_t)this->functionVariantsOptimizer.infos.size();
-    if ( table->count > 0 )
-        memcpy(table->entries, &this->functionVariantsOptimizer.infos[0], sizeof(dyld_cache_function_variant_entry)*this->functionVariantsOptimizer.infos.size());
-}
-
 
 void SharedCacheBuilder::emitCacheDylibsTrie()
 {
@@ -8601,179 +7913,6 @@
     return Error::none();
 }
 
-void SharedCacheBuilder::addSubCacheFileInfo(uint64_t cacheVMAddress, PropertyList::Array &files, const SubCache &subCache) {
-    using Array         = PropertyList::Array;
-    using Integer       = PropertyList::Integer;
-    using String        = PropertyList::String;
-    using Dictionary    = PropertyList::Dictionary;
-
-    uuid_t subcacheUUID;
-    uuid_parse(subCache.uuidString, subcacheUUID);
-    auto& subCacheFile = files.addObject<Dictionary>();
-
-    subCacheFile.addObjectForKey<String>("name", options.mainCacheFileName + subCache.fileSuffix);
-    subCacheFile.addObjectForKey<PropertyList::UUID>(kDyldAtlasSharedCacheUUIDKey,subcacheUUID);
-    subCacheFile.addObjectForKey<Integer>("voff",subCache.subCacheVMAddress.rawValue()-cacheVMAddress);
-    subCacheFile.addObjectForKey<Integer>("fsze", subCache.bufferSize);
-    subCacheFile.addObjectForKey<Integer>("padr", subCache.subCacheVMAddress.rawValue());
-    auto& mappingsArray = subCacheFile.addObjectForKey<Array>(kDyldAtlasSharedCacheMappingArrayKey);
-
-    dyld_cache_header* subCacheHeader   = (dyld_cache_header*)subCache.buffer;
-    auto* mappings                      = (dyld_cache_mapping_info*)((uint8_t*)subCacheHeader + subCacheHeader->mappingOffset);
-
-    uint64_t lastAddress = 0;
-    for ( auto i = 0; i < subCacheHeader->mappingCount; ++i) {
-        auto& mapping = mappingsArray.addObject<Dictionary>();
-        mapping.addObjectForKey<Integer>(kDyldAtlasSharedCacheMappingsSizeKey, mappings[i].size);
-        mapping.addObjectForKey<Integer>(kDyldAtlasSharedCacheMappingsPreferredLoadAddressKey, mappings[i].address);
-        mapping.addObjectForKey<Integer>(kDyldAtlasSharedCacheMappingsFileOffsetKey, mappings[i].fileOffset);
-        mapping.addObjectForKey<Integer>(kDyldAtlasSharedCacheMappingsMaxProtKey, mappings[i].maxProt);
-        if (mappings[i].address + mappings[i].size > lastAddress) {
-            lastAddress = mappings[i].address + mappings[i].size;
-        }
-    }
-    subCacheFile.addObjectForKey<Integer>("size", lastAddress-subCacheHeader->sharedRegionStart);
-}
-
-void SharedCacheBuilder::addCacheAtlasInfo(PropertyList::Dictionary *cacheAtlas, const SubCache &mainCache) {
-    using Array         = PropertyList::Array;
-    using Integer       = PropertyList::Integer;
-    using String        = PropertyList::String;
-
-    uint64_t cacheVMAddress = mainCache.subCacheVMAddress.rawValue();
-    uuid_t cacheUUID;
-    uuid_parse(mainCache.uuidString, cacheUUID);
-    cacheAtlas->addObjectForKey<PropertyList::UUID>(kDyldAtlasSharedCacheUUIDKey, cacheUUID);
-    cacheAtlas->addObjectForKey<Integer>(kDyldAtlasSharedCachePreferredLoadAddressKey, mainCache.subCacheVMAddress.rawValue());
-    cacheAtlas->addObjectForKey<Integer>(kDyldAtlasSharedCacheVMSizeKey, this->totalVMSize.rawValue());
-    dyld_cache_header*   cacheHeader        = (dyld_cache_header*)mainCache.buffer;
-
-    if (!uuid_is_null(cacheHeader->symbolFileUUID)) {
-        cacheAtlas->addObjectForKey<String>(kDyldAtlasSharedCacheSymbolFileName, options.mainCacheFileName + ".symbols");
-        cacheAtlas->addObjectForKey<PropertyList::UUID>(kDyldAtlasSharedCacheSymbolFileName, cacheHeader->symbolFileUUID);
-    }
-
-    auto& files = cacheAtlas->addObjectForKey<Array>("dscs");
-    addSubCacheFileInfo(cacheVMAddress, files, mainCache);
-    for (auto& subCache : mainCache.subCaches) {
-        addSubCacheFileInfo(cacheVMAddress, files, *subCache);
-    }
-
-    // FIXME: Remove once deprecate legacy APIs that need this
-    if (strncmp(cacheHeader->magic, "dyld_v1arm64_32", 15) != 0) {
-        cacheAtlas->addObjectForKey<Integer>("psze", 4);
-    } else {
-        cacheAtlas->addObjectForKey<Integer>("psze", 8);
-    }
-}
-
-// This generates the atlas binary plist included with the shared cache
-void SharedCacheBuilder::buildAtlas() {
-    STACK_ALLOCATOR(allocator, 0);
-    using Array         = PropertyList::Array;
-    using Dictionary    = PropertyList::Dictionary;
-    using Integer       = PropertyList::Integer;
-    using String        = PropertyList::String;
-    auto propertyListEncoder            = PropertyList(allocator);
-    auto& rootDictionary                = propertyListEncoder.rootDictionary();
-    // The same plist contains both the customer and shared cache data, since they share layouts
-    // We include dictionaries at the root so they can be lookup by leaf name or UUID
-    auto& byUuidDictionary              = rootDictionary.addObjectForKey<Dictionary>("uuids");
-    auto& byNameDictionary              = rootDictionary.addObjectForKey<Dictionary>("names");
-    Dictionary* customerCacheAtlas      = nullptr;
-    Dictionary* devCacheAtlas           = nullptr;
-    Array* images                       = nullptr;
-    uuid_string_t customerCacheUUID     = {0};
-    uuid_string_t devCacheUUID          = {0};
-    std::string   customerCacheName;
-    std::string   devCacheName;
-
-    for ( const SubCache& subCache : this->subCaches ) {
-        if ( subCache.isMainCustomerCache() ) {
-            customerCacheName = options.mainCacheFileName + subCache.fileSuffix;
-            customerCacheAtlas = &byUuidDictionary.addObjectForKey<Dictionary>(subCache.uuidString);
-            byNameDictionary.insertObjectForKey(customerCacheName, *customerCacheAtlas);
-            addCacheAtlasInfo(customerCacheAtlas, subCache);
-            strcpy(customerCacheUUID, subCache.uuidString);
-        } else if ( subCache.isMainDevelopmentCache() ) {
-            devCacheName = options.mainCacheFileName + subCache.fileSuffix;
-            devCacheAtlas = &byUuidDictionary.addObjectForKey<Dictionary>(subCache.uuidString);
-            byNameDictionary.insertObjectForKey(devCacheName, *devCacheAtlas);
-            addCacheAtlasInfo(devCacheAtlas, subCache);
-            strcpy(devCacheUUID, subCache.uuidString);
-        }
-    }
-    assert((customerCacheAtlas != nullptr) || (devCacheAtlas != nullptr));
-
-    // The bplist00 format supports uniquing objects, but uniquing collections is slow. Since we know a priori the images for both cache variants
-    // will be the same we create it int he first cache atlas, and if there is a second we insert a reference to the already existing one.
-    if (customerCacheAtlas) {
-        images = &customerCacheAtlas->addObjectForKey<Array>(kDyldAtlasSharedCacheImageArrayKey);
-        if (devCacheAtlas) {
-            devCacheAtlas->insertObjectForKey(kDyldAtlasSharedCacheImageArrayKey, *images);
-        }
-    } else {
-        images = &devCacheAtlas->addObjectForKey<Array>(kDyldAtlasSharedCacheImageArrayKey);
-    }
-
-    for ( const CacheDylib& cacheDylib : this->cacheDylibs ) {
-        auto& image = images->addObject<Dictionary>();
-        auto& segments = image.addObjectForKey<Array>(kDyldAtlasImageSegmentArrayKey);
-        image.addObjectForKey<String>(kDyldAtlasImageInstallnameKey, cacheDylib.installName);
-        image.addObjectForKey<Integer>(kDyldAtlasImagePreferredLoadAddressKey, cacheDylib.cacheLoadAddress.rawValue());
-        uuid_t uuid;
-        assert(cacheDylib.cacheHdr->getUuid(uuid));
-        image.addObjectForKey<PropertyList::UUID>(kDyldAtlasImageUUIDKey, uuid);
-
-        for ( const DylibSegmentChunk& segmentChunk : cacheDylib.segments ) {
-            auto& segment = segments.addObject<Dictionary>();
-            segment.addObjectForKey<String>(kDyldAtlasSegmentNameKey, segmentChunk.name());
-            segment.addObjectForKey<Integer>(kDyldAtlasSegmentPreferredLoadAddressKey, segmentChunk.cacheVMAddress.rawValue());
-            segment.addObjectForKey<Integer>(kDyldAtlasSegmentSizeKey, segmentChunk.cacheVMSize.rawValue());
-            segment.addObjectForKey<Integer>(kDyldAtlasSegmentFileOffsetKey, segmentChunk.subCacheFileOffset.rawValue());
-            segment.addObjectForKey<Integer>(kDyldAtlasSegmentFileSizeKey, segmentChunk.subCacheFileSize.rawValue());
-            if ( strcmp("__TEXT", segmentChunk.name()) == 0 ) {
-                segment.addObjectForKey<Integer>(kDyldAtlasSegmentPermissionsKey, VM_PROT_READ | VM_PROT_EXECUTE);
-            } else if ( strcmp("__LINKEDIT", segmentChunk.name()) == 0 ) {
-                segment.addObjectForKey<Integer>(kDyldAtlasSegmentPermissionsKey, VM_PROT_READ);
-            } else {
-                segment.addObjectForKey<Integer>(kDyldAtlasSegmentPermissionsKey, VM_PROT_READ | VM_PROT_WRITE);
-            }
-        }
-    }
-
-    ByteStream fileStream(allocator);
-    propertyListEncoder.encode(fileStream);
-    AAREncoder aarEncoder(allocator);
-
-    if (customerCacheUUID[0]) {
-        std::string plistPath = std::string("caches/uuids/") + customerCacheUUID + ".plist";
-        std::string symlinkTarget = std::string("../uuids/") + customerCacheUUID + ".plist";
-        std::string symlinkSource = std::string("caches/names/") + customerCacheName + ".plist";
-
-        aarEncoder.addFile(plistPath, fileStream.span());
-        aarEncoder.addSymLink(symlinkSource, symlinkTarget);
-        if (devCacheUUID[0]) {
-            std::string devPlistPath = std::string("caches/uuids/") + devCacheUUID + ".plist";
-            std::string devSymlinkSource = std::string("caches/names/") + devCacheName + ".plist";
-            aarEncoder.addSymLink(devPlistPath, symlinkTarget);
-            aarEncoder.addSymLink(devSymlinkSource, symlinkTarget);
-        }
-    } else {
-        assert(devCacheUUID[0] != 0);
-        std::string plistPath = std::string("caches/uuids/") + devCacheUUID + ".plist";
-        std::string symlinkTarget = std::string("../uuids/") + devCacheUUID + ".plist";
-        std::string symlinkSource = std::string("caches/names/") + devCacheName + ".plist";
-
-        aarEncoder.addFile(plistPath, fileStream.span());
-        aarEncoder.addSymLink(symlinkSource, symlinkTarget);
-    }
-
-    ByteStream outputStream(allocator);
-    aarEncoder.encode(outputStream);
-    std::copy(outputStream.begin(), outputStream.end(), std::back_insert_iterator(atlasData));
-}
-
 void SharedCacheBuilder::computeCacheHeaders()
 {
     Timer::Scope timedScope(this->config, "computeCacheHeaders time");
@@ -8791,13 +7930,13 @@
         // look for libdyld.dylib and record OS verson info into cache header
         for ( const CacheDylib& cacheDylib : this->cacheDylibs ) {
             if ( endsWith(cacheDylib.installName, "/libdyld.dylib") ) {
-                cacheDylib.inputHdr->platformAndVersions().unzip(^(mach_o::PlatformAndVersions pvs) {
-                    if ( pvs.platform == options.platform ) {
-                        osVersion = pvs.minOS.value();
+                cacheDylib.inputMF->forEachSupportedPlatform(^(dyld3::Platform platform, uint32_t minOS, uint32_t sdk) {
+                    if ( platform == options.platform ) {
+                        osVersion = minOS;
                     }
                     else {
-                        altPlatform = pvs.platform.value();
-                        altOsVersion = pvs.minOS.value();
+                        altPlatform  = (uint32_t)platform;
+                        altOsVersion = minOS;
                     }
                 });
             }
@@ -8806,7 +7945,7 @@
                 dyldInCacheUnslidAddr = cacheDylib.cacheLoadAddress;
                 uint64_t dyldEntryOffset;
                 bool     usesCRT;
-                if ( cacheDylib.cacheHdr->getEntry(dyldEntryOffset, usesCRT) ) {
+                if ( cacheDylib.cacheMF->getEntry(dyldEntryOffset, usesCRT) ) {
                     // the "pc" value in the LC_UNIXTHREAD was adjusted when dyld was placed in the cache
                     dyldInCacheEntryUnslidAddr = dyldInCacheUnslidAddr + VMOffset(dyldEntryOffset);
                 }
@@ -8823,9 +7962,8 @@
                                             osVersion, altPlatform, altOsVersion,
                                             dyldInCacheUnslidAddr, dyldInCacheEntryUnslidAddr,
                                             this->dylibTrieOptimizer,
-                                            this->objcOptimizer, this->swiftOptimizer,
-                                            this->patchTableOptimizer, this->functionVariantsOptimizer,
-                                            this->prebuiltLoaderBuilder, this->prewarmingOptimizer);
+                                            this->objcOptimizer, this->swiftProtocolConformanceOptimizer,
+                                            this->patchTableOptimizer, this->prebuiltLoaderBuilder);
             continue;
         }
 
@@ -8913,7 +8051,7 @@
     return swiftPrespecializedDylibBuildError;
 }
 
-void SharedCacheBuilder::getResults(std::vector<CacheBuffer>& results, std::vector<std::byte>& atlas) const
+void SharedCacheBuilder::getResults(std::vector<CacheBuffer>& results) const
 {
     for ( const SubCache& subCache : this->subCaches ) {
         CacheBuffer buffer;
@@ -8935,7 +8073,6 @@
 #endif
 
         results.push_back(std::move(buffer));
-        atlas = std::move(this->atlasData);
     }
 }
 
@@ -9009,32 +8146,31 @@
 
     assert(mainSubCache.isMainCache());
 
-    json::Node cacheNode;
+    dyld3::json::Node cacheNode;
 
     cacheNode.map["version"].value = "1";
     cacheNode.map["disposition"].value = disposition;
-    cacheNode.map["arch"].value = this->options.archs.name();
-    cacheNode.map["platform"].value = mach_o::Platform(this->options.platform).name();
-    cacheNode.map["base-address"].value = json::hex(baseAddress);
+    cacheNode.map["base-address"].value = dyld3::json::hex(baseAddress);
     cacheNode.map["uuid"].value = mainSubCache.uuidString;
 
-    json::Node imagesNode;
+    dyld3::json::Node imagesNode;
     for ( const CacheDylib& cacheDylib : this->cacheDylibs ) {
-        json::Node imageNode;
+        dyld3::json::Node imageNode;
         imageNode.map["path"].value = cacheDylib.installName;
+        const dyld3::MachOFile* mf = cacheDylib.cacheMF;
         uuid_t uuid;
-        if ( cacheDylib.cacheHdr->getUuid(uuid) ) {
+        if ( mf->getUuid(uuid) ) {
             uuid_string_t uuidStr;
             uuid_unparse(uuid, uuidStr);
             imageNode.map["uuid"].value = uuidStr;
         }
 
-        __block json::Node segmentsNode;
-        cacheDylib.cacheHdr->forEachSegment(^(const Header::SegmentInfo &info, bool &stop) {
-            json::Node segmentNode;
-            segmentNode.map["name"].value = info.segmentName;
-            segmentNode.map["start-vmaddr"].value = json::hex(info.vmaddr);
-            segmentNode.map["end-vmaddr"].value = json::hex(info.vmaddr + info.vmsize);
+        __block dyld3::json::Node segmentsNode;
+        mf->forEachSegment(^(const dyld3::MachOAnalyzer::SegmentInfo &info, bool &stop) {
+            dyld3::json::Node segmentNode;
+            segmentNode.map["name"].value = info.segName;
+            segmentNode.map["start-vmaddr"].value = dyld3::json::hex(info.vmAddr);
+            segmentNode.map["end-vmaddr"].value = dyld3::json::hex(info.vmAddr + info.vmSize);
 
             // Add sections in verbose mode
             segmentsNode.array.push_back(segmentNode);
@@ -9115,9 +8251,9 @@
 {
     va_list list;
     va_start(list, format);
-    _SIMPLE_STRING buffer = _simple_salloc();
+    void* buffer = _simple_salloc();
     _simple_vsprintf(buffer, format, list);
-    this->warnings.push_back(_simple_string(buffer));
+    this->warnings.push_back((const char*)buffer);
     _simple_sfree(buffer);
     va_end(list);