This is xnu-8019. See this file in:
# options

OPTIONS/iokitcpp					optional iokitcpp
OPTIONS/kdebug						optional kdebug
OPTIONS/networking					optional networking
OPTIONS/hibernation					optional hibernation
OPTIONS/crypto						optional crypto
OPTIONS/config_dtrace				optional config_dtrace
OPTIONS/mach_assert				optional mach_assert

# iig generated implementation files

./DriverKit/OSObject.iig.cpp		optional iokitcpp
./DriverKit/OSAction.iig.cpp		optional iokitcpp
./DriverKit/IOService.iig.cpp		optional iokitcpp
./DriverKit/IOUserClient.iig.cpp		optional iokitcpp
./DriverKit/IOMemoryDescriptor.iig.cpp		optional iokitcpp
./DriverKit/IOBufferMemoryDescriptor.iig.cpp		optional iokitcpp
./DriverKit/IOMemoryMap.iig.cpp		optional iokitcpp
./DriverKit/IODispatchSource.iig.cpp		optional iokitcpp
./DriverKit/IODispatchQueue.iig.cpp		optional iokitcpp
./DriverKit/IOInterruptDispatchSource.iig.cpp		optional iokitcpp
./DriverKit/IODataQueueDispatchSource.iig.cpp		optional iokitcpp
./DriverKit/IOServiceNotificationDispatchSource.iig.cpp		optional iokitcpp
./DriverKit/IOServiceStateNotificationDispatchSource.iig.cpp		optional iokitcpp
./DriverKit/IOEventLink.iig.cpp		optional iokitcpp
./DriverKit/IOWorkGroup.iig.cpp		optional iokitcpp
./DriverKit/IOUserServer.iig.cpp		optional iokitcpp
./DriverKit/IODMACommand.iig.cpp		optional iokitcpp

# libIOKit

iokit/Kernel/IOHibernateIO.cpp				optional hibernation
iokit/Kernel/IOHibernateRestoreKernel.c			optional hibernation

iokit/Kernel/IOLib.cpp					optional iokitcpp
iokit/Kernel/IOLocks.cpp				optional iokitcpp
iokit/Kernel/IOConditionLock.cpp			optional iokitcpp

#iokit/Kernel/IORuntime.cpp				optional iokitcpp
iokit/Kernel/IOStartIOKit.cpp				optional iokitcpp

iokit/Kernel/IODeviceTreeSupport.cpp			optional iokitcpp

iokit/Kernel/IORegistryEntry.cpp			optional iokitcpp
iokit/Kernel/IOService.cpp				optional iokitcpp
iokit/Kernel/IOServicePM.cpp				optional iokitcpp
iokit/Kernel/IOPMinformee.cpp				optional iokitcpp
iokit/Kernel/IOPMinformeeList.cpp			optional iokitcpp
iokit/Kernel/IOPMPowerStateQueue.cpp			optional iokitcpp
iokit/Kernel/IOCatalogue.cpp				optional iokitcpp
iokit/Kernel/IOPMPowerSource.cpp			optional iokitcpp
iokit/Kernel/IOPMPowerSourceList.cpp			optional iokitcpp
iokit/Kernel/IOPMGR.cpp					optional iokitcpp
iokit/Kernel/IOPolledInterface.cpp			optional iokitcpp

iokit/Kernel/IOWorkLoop.cpp				optional iokitcpp
iokit/Kernel/IOEventSource.cpp				optional iokitcpp
iokit/Kernel/IOInterruptEventSource.cpp			optional iokitcpp
iokit/Kernel/IOCommandGate.cpp				optional iokitcpp
iokit/Kernel/IOCommand.cpp				optional iokitcpp
iokit/Kernel/IOCommandPool.cpp				optional iokitcpp
iokit/Kernel/IOCommandQueue.cpp				optional iokitcpp
iokit/Kernel/IODMAEventSource.cpp			optional iokitcpp
iokit/Kernel/IOFilterInterruptEventSource.cpp		optional iokitcpp
iokit/Kernel/IOTimerEventSource.cpp			optional iokitcpp

# Memory system
iokit/Kernel/IOBufferMemoryDescriptor.cpp		optional iokitcpp
iokit/Kernel/IODMACommand.cpp				optional iokitcpp
iokit/Kernel/IODeviceMemory.cpp				optional iokitcpp
iokit/Kernel/IOInterleavedMemoryDescriptor.cpp		optional iokitcpp
iokit/Kernel/IOMapper.cpp				optional iokitcpp
iokit/Kernel/IOMemoryCursor.cpp				optional iokitcpp
iokit/Kernel/IOMemoryDescriptor.cpp			optional iokitcpp
iokit/Kernel/IOMultiMemoryDescriptor.cpp		optional iokitcpp
iokit/Kernel/IORangeAllocator.cpp			optional iokitcpp
iokit/Kernel/IOSubMemoryDescriptor.cpp			optional iokitcpp
iokit/Kernel/IOGuardPageMemoryDescriptor.cpp		optional iokitcpp

iokit/Kernel/IOPlatformExpert.cpp			optional iokitcpp
iokit/Kernel/IOPlatformIO.cpp				optional iokitcpp

iokit/Kernel/IOCPU.cpp					optional iokitcpp
iokit/Kernel/IOPlatformActions.cpp			optional iokitcpp

iokit/Kernel/IONVRAM.cpp				optional iokitcpp

iokit/Kernel/IODMAController.cpp			optional iokitcpp
iokit/Kernel/IOInterruptController.cpp			optional iokitcpp
iokit/Kernel/PassthruInterruptController.cpp		optional iokitcpp

iokit/Kernel/IOUserClient.cpp				optional iokitcpp

iokit/Kernel/IOKitDebug.cpp				optional iokitcpp
iokit/Kernel/IODataQueue.cpp				optional iokitcpp
iokit/Kernel/IOSharedDataQueue.cpp			optional iokitcpp

# IOKit tests
iokit/Tests/Tests.cpp					optional iokitcpp
iokit/Tests/TestIOMemoryDescriptor.cpp      optional iokitcpp
# iokit/Tests/TestDevice.cpp                optional iokitcpp
# iokit/Tests/TestContainers.cpp            optional iokitcpp
# iokit/Tests/TestCollections.cpp           optional iokitcpp
iokit/Tests/TestServices/TestIOConnectMapMemoryPortLeak45265408.cpp optional iokitcpp
iokit/Tests/TestServices/TestIODeviceMemoryRosetta.cpp optional iokitcpp
iokit/Tests/TestServices/TestIOServiceUserNotification.cpp optional iokitcpp

iokit/Kernel/IOStatistics.cpp				optional iokitcpp
iokit/Kernel/IOInterruptAccounting.cpp			optional iokitcpp

iokit/Kernel/IOReporter.cpp				optional iokitcpp
iokit/Kernel/IOSimpleReporter.cpp			optional iokitcpp
iokit/Kernel/IOStateReporter.cpp			optional iokitcpp
iokit/Kernel/IOHistogramReporter.cpp			optional iokitcpp
iokit/Kernel/IOReportLegend.cpp				optional iokitcpp

iokit/Kernel/IORTC.cpp				optional iokitcpp

iokit/Kernel/IOStringFuncs.c				standard

iokit/Kernel/IOUserServer.cpp				optional iokitcpp

# Property tables for kernel-linked objects

iokit/KernelConfigTables.cpp				optional iokitcpp

# BSD shim files

iokit/bsddev/IOKitBSDInit.cpp				optional iokitcpp

# Disk Image
iokit/bsddev/DINetBootHook.cpp				optional iokitcpp

# Power Management
iokit/Kernel/RootDomainUserClient.cpp			optional iokitcpp
iokit/Kernel/IOPowerConnection.cpp			optional iokitcpp

# System Management
iokit/Families/IOSystemManagement/IOWatchDogTimer.cpp	optional iokitcpp

# Performance Control
iokit/Kernel/IOPerfControl.cpp		optional iokitcpp

# Skywalk
iokit/bsddev/skywalk/IOSkywalkSupport.cpp		optional iokitcpp skywalk