ARMFrameLowering.cpp File Reference

#include "ARMFrameLowering.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBaseRegisterInfo.h"
#include "ARMConstantPoolValue.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
#include "MCTargetDesc/ARMAddressingModes.h"
#include "MCTargetDesc/ARMBaseInfo.h"
#include "Utils/ARMBaseInfo.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/Function.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <utility>
#include <vector>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "arm-frame-lowering"

Enumerations
enum class	SpillArea {   GPRCS1 , GPRCS2 , DPRCS1 , DPRCS2 ,   GPRCS3 , FPCXT }

Functions
static MachineBasicBlock::iterator	skipAlignedDPRCS2Spills (MachineBasicBlock::iterator MI, unsigned NumAlignedDPRCS2Regs)
	Skip past the code inserted by emitAlignedDPRCS2Spills, and return an iterator to the following instruction.
SpillArea	getSpillArea (Register Reg, ARMSubtarget::PushPopSplitVariation Variation, unsigned NumAlignedDPRCS2Regs, const ARMBaseRegisterInfo *RegInfo)
	Get the spill area that Reg should be saved into in the prologue.
static int	getArgumentStackToRestore (MachineFunction &MF, MachineBasicBlock &MBB)
static bool	needsWinCFI (const MachineFunction &MF)
static MachineBasicBlock::iterator	insertSEH (MachineBasicBlock::iterator MBBI, const TargetInstrInfo &TII, unsigned Flags)
static MachineBasicBlock::iterator	initMBBRange (MachineBasicBlock &MBB, const MachineBasicBlock::iterator &MBBI)
static void	insertSEHRange (MachineBasicBlock &MBB, MachineBasicBlock::iterator Start, const MachineBasicBlock::iterator &End, const ARMBaseInstrInfo &TII, unsigned MIFlags)
static void	emitRegPlusImmediate (bool isARM, MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, const DebugLoc &dl, const ARMBaseInstrInfo &TII, unsigned DestReg, unsigned SrcReg, int NumBytes, unsigned MIFlags=MachineInstr::NoFlags, ARMCC::CondCodes Pred=ARMCC::AL, unsigned PredReg=0)
static void	emitSPUpdate (bool isARM, MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, const DebugLoc &dl, const ARMBaseInstrInfo &TII, int NumBytes, unsigned MIFlags=MachineInstr::NoFlags, ARMCC::CondCodes Pred=ARMCC::AL, unsigned PredReg=0)
static int	sizeOfSPAdjustment (const MachineInstr &MI)
static bool	WindowsRequiresStackProbe (const MachineFunction &MF, size_t StackSizeInBytes)
static void	emitAligningInstructions (MachineFunction &MF, ARMFunctionInfo *AFI, const TargetInstrInfo &TII, MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, const DebugLoc &DL, const unsigned Reg, const Align Alignment, const bool MustBeSingleInstruction)
	Emit an instruction sequence that will align the address in register Reg by zero-ing out the lower bits.
static int	getMaxFPOffset (const ARMSubtarget &STI, const ARMFunctionInfo &AFI, const MachineFunction &MF)
	We need the offset of the frame pointer relative to other MachineFrameInfo offsets which are encoded relative to SP at function begin.
static void	emitAlignedDPRCS2Spills (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned NumAlignedDPRCS2Regs, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI)
	Emit aligned spill instructions for NumAlignedDPRCS2Regs D-registers starting from d8.
static void	emitAlignedDPRCS2Restores (MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned NumAlignedDPRCS2Regs, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI)
	Emit aligned reload instructions for NumAlignedDPRCS2Regs D-registers starting from d8.
static unsigned	EstimateFunctionSizeInBytes (const MachineFunction &MF, const ARMBaseInstrInfo &TII)
static unsigned	estimateRSStackSizeLimit (MachineFunction &MF, const TargetFrameLowering *TFI, bool &HasNonSPFrameIndex)
	estimateRSStackSizeLimit - Look at each instruction that references stack frames and return the stack size limit beyond which some of these instructions will require a scratch register during their expansion later.
static void	checkNumAlignedDPRCS2Regs (MachineFunction &MF, BitVector &SavedRegs)
static bool	canSpillOnFrameIndexAccess (const MachineFunction &MF, const TargetFrameLowering &TFI)
static uint32_t	alignToARMConstant (uint32_t Value)
	Get the minimum constant for ARM that is greater than or equal to the argument.

Variables
static cl::opt< bool >	SpillAlignedNEONRegs ("align-neon-spills", cl::Hidden, cl::init(true), cl::desc("Align ARM NEON spills in prolog and epilog"))
static const uint64_t	kSplitStackAvailable = 256

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "arm-frame-lowering"

Definition at line 163 of file ARMFrameLowering.cpp.

Enumeration Type Documentation

SpillArea

enum class SpillArea

strong

Enumerator
GPRCS1
GPRCS2
DPRCS1
DPRCS2
GPRCS3
FPCXT

Definition at line 175 of file ARMFrameLowering.cpp.

Function Documentation

alignToARMConstant()

static uint32_t alignToARMConstant ( uint32_t  Value )

static

Get the minimum constant for ARM that is greater than or equal to the argument.

In ARM, constants can have any value that can be produced by rotating an 8-bit value to the right by an even number of bits within a 32-bit word.

Definition at line 3102 of file ARMFrameLowering.cpp.

Referenced by llvm::ARMFrameLowering::adjustForSegmentedStacks().

canSpillOnFrameIndexAccess()

static bool canSpillOnFrameIndexAccess ( const MachineFunction &  MF, const TargetFrameLowering &  TFI  )

static

Definition at line 2393 of file ARMFrameLowering.cpp.

References contains(), llvm::TargetFrameLowering::getFrameIndexReference(), llvm::MachineFunction::getInfo(), llvm::MachineFunction::getSubtarget(), llvm::ARMFunctionInfo::isThumb1OnlyFunction(), MBB, and MI.

Referenced by llvm::ARMFrameLowering::determineCalleeSaves().

checkNumAlignedDPRCS2Regs()

static void checkNumAlignedDPRCS2Regs ( MachineFunction &  MF, BitVector &  SavedRegs  )

static

Definition at line 2324 of file ARMFrameLowering.cpp.

References llvm::ARMBaseRegisterInfo::canRealignStack(), llvm::TargetSubtargetInfo::getFrameLowering(), llvm::MachineFunction::getFunction(), llvm::MachineFunction::getInfo(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::TargetFrameLowering::getStackAlign(), llvm::MachineFunction::getSubtarget(), llvm::Function::hasFnAttribute(), llvm::BitVector::set(), SpillAlignedNEONRegs, and llvm::BitVector::test().

Referenced by llvm::ARMFrameLowering::determineCalleeSaves().

emitAlignedDPRCS2Restores()

static void emitAlignedDPRCS2Restores ( MachineBasicBlock &  MBB, MachineBasicBlock::iterator  MI, unsigned  NumAlignedDPRCS2Regs, ArrayRef< CalleeSavedInfo >  CSI, const TargetRegisterInfo *  TRI  )

static

Emit aligned reload instructions for NumAlignedDPRCS2Regs D-registers starting from d8.

These instructions are assumed to execute while the stack is still aligned, unlike the code inserted by emitPopInst.

Definition at line 2014 of file ARMFrameLowering.cpp.

References llvm::MachineInstrBuilder::add(), llvm::MachineInstrBuilder::addFrameIndex(), llvm::MachineInstrBuilder::addImm(), llvm::MachineInstrBuilder::addReg(), llvm::MachineInstr::addRegisterKilled(), llvm::ARMCC::AL, assert(), llvm::BuildMI(), llvm::condCodeOp(), llvm::RegState::Define, DL, llvm::MachineBasicBlock::end(), llvm::MachineFunction::getInfo(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::MachineBasicBlock::getParent(), llvm::MachineFunction::getSubtarget(), I, llvm::RegState::ImplicitDefine, isThumb(), llvm::ARMFunctionInfo::isThumb1OnlyFunction(), llvm::ARMFunctionInfo::isThumbFunction(), llvm::RegState::Kill, MBB, MI, llvm::predOps(), TII, and TRI.

Referenced by llvm::ARMFrameLowering::restoreCalleeSavedRegisters().

emitAlignedDPRCS2Spills()

static void emitAlignedDPRCS2Spills ( MachineBasicBlock &  MBB, MachineBasicBlock::iterator  MI, unsigned  NumAlignedDPRCS2Regs, ArrayRef< CalleeSavedInfo >  CSI, const TargetRegisterInfo *  TRI  )

static

Emit aligned spill instructions for NumAlignedDPRCS2Regs D-registers starting from d8.

Also insert stack realignment code and leave the stack pointer pointing to the d8 spill slot.

Definition at line 1841 of file ARMFrameLowering.cpp.

References llvm::MachineInstrBuilder::add(), llvm::MachineInstrBuilder::addImm(), llvm::MachineBasicBlock::addLiveIn(), llvm::MachineInstrBuilder::addReg(), llvm::MachineInstr::addRegisterKilled(), llvm::ARMCC::AL, assert(), llvm::BuildMI(), llvm::condCodeOp(), DL, emitAligningInstructions(), llvm::MachineBasicBlock::end(), llvm::MachineFunction::getFrameInfo(), llvm::MachineFunction::getInfo(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::MachineFrameInfo::getMaxAlign(), llvm::MachineBasicBlock::getParent(), llvm::MachineFunction::getSubtarget(), I, llvm::RegState::ImplicitKill, isThumb(), llvm::ARMFunctionInfo::isThumb1OnlyFunction(), llvm::ARMFunctionInfo::isThumbFunction(), llvm::RegState::Kill, MBB, MI, llvm::predOps(), llvm::MachineFrameInfo::setObjectAlignment(), llvm::ARMFunctionInfo::setShouldRestoreSPFromFP(), TII, and TRI.

Referenced by llvm::ARMFrameLowering::spillCalleeSavedRegisters().

emitAligningInstructions()

static void emitAligningInstructions ( MachineFunction &  MF, ARMFunctionInfo *  AFI, const TargetInstrInfo &  TII, MachineBasicBlock &  MBB, MachineBasicBlock::iterator  MBBI, const DebugLoc &  DL, const unsigned  Reg, const Align  Alignment, const bool  MustBeSingleInstruction  )

static

Emit an instruction sequence that will align the address in register Reg by zero-ing out the lower bits.

For versions of the architecture that support Neon, this must be done in a single instruction, since skipAlignedDPRCS2Spills assumes it is done in a single instruction. That function only gets called when optimizing spilling of D registers on a core with the Neon instruction set present.

Definition at line 799 of file ARMFrameLowering.cpp.

References llvm::MachineInstrBuilder::add(), llvm::MachineInstrBuilder::addImm(), llvm::MachineInstrBuilder::addReg(), llvm::ARMCC::AL, assert(), llvm::BuildMI(), llvm::condCodeOp(), DL, llvm::ARM_AM::getSORegOpc(), llvm::MachineFunction::getSubtarget(), llvm::ARMFunctionInfo::isThumb1OnlyFunction(), llvm::ARMFunctionInfo::isThumbFunction(), llvm::RegState::Kill, llvm::Log2(), llvm::ARM_AM::lsl, llvm::ARM_AM::lsr, MBB, MBBI, llvm::predOps(), TII, and llvm::Align::value().

Referenced by emitAlignedDPRCS2Spills(), and llvm::ARMFrameLowering::emitPrologue().

emitRegPlusImmediate()

static void emitRegPlusImmediate ( bool  isARM, MachineBasicBlock &  MBB, MachineBasicBlock::iterator &  MBBI, const DebugLoc &  dl, const ARMBaseInstrInfo &  TII, unsigned  DestReg, unsigned  SrcReg, int  NumBytes, unsigned  MIFlags = MachineInstr::NoFlags, ARMCC::CondCodes  Pred = ARMCC::AL, unsigned  PredReg = 0  )

static

Definition at line 671 of file ARMFrameLowering.cpp.

References llvm::emitARMRegPlusImmediate(), llvm::emitT2RegPlusImmediate(), MBB, MBBI, and TII.

Referenced by llvm::ARMFrameLowering::emitPrologue(), and emitSPUpdate().

emitSPUpdate()

static void emitSPUpdate ( bool  isARM, MachineBasicBlock &  MBB, MachineBasicBlock::iterator &  MBBI, const DebugLoc &  dl, const ARMBaseInstrInfo &  TII, int  NumBytes, unsigned  MIFlags = MachineInstr::NoFlags, ARMCC::CondCodes  Pred = ARMCC::AL, unsigned  PredReg = 0  )

static

Definition at line 684 of file ARMFrameLowering.cpp.

References emitRegPlusImmediate(), MBB, MBBI, and TII.

Referenced by llvm::ARMFrameLowering::emitEpilogue(), and llvm::ARMFrameLowering::emitPrologue().

EstimateFunctionSizeInBytes()

static unsigned EstimateFunctionSizeInBytes ( const MachineFunction &  MF, const ARMBaseInstrInfo &  TII  )

static

Definition at line 2221 of file ARMFrameLowering.cpp.

References llvm::MachineFunction::getConstantPool(), llvm::MachineConstantPool::getConstants(), llvm::MachineFunction::getJumpTableInfo(), llvm::MachineJumpTableInfo::getJumpTables(), MBB, MI, and TII.

Referenced by llvm::ARMFrameLowering::determineCalleeSaves(), and llvm::CSKYFrameLowering::determineCalleeSaves().

estimateRSStackSizeLimit()

static unsigned estimateRSStackSizeLimit ( MachineFunction &  MF, const TargetFrameLowering *  TFI, bool &  HasNonSPFrameIndex  )

static

estimateRSStackSizeLimit - Look at each instruction that references stack frames and return the stack size limit beyond which some of these instructions will require a scratch register during their expansion later.

Definition at line 2239 of file ARMFrameLowering.cpp.

References llvm::ARMII::AddrMode2, llvm::ARMII::AddrMode3, llvm::ARMII::AddrMode4, llvm::ARMII::AddrMode5, llvm::ARMII::AddrMode5FP16, llvm::ARMII::AddrMode6, llvm::ARMII::AddrMode_i12, llvm::ARMII::AddrModeMask, llvm::ARMII::AddrModeT2_i12, llvm::ARMII::AddrModeT2_i7, llvm::ARMII::AddrModeT2_i7s2, llvm::ARMII::AddrModeT2_i7s4, llvm::ARMII::AddrModeT2_i8neg, llvm::ARMII::AddrModeT2_i8s4, llvm::ARMII::AddrModeT2_ldrex, llvm::TargetRegisterClass::contains(), llvm::MachineFunction::getInfo(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), llvm::TargetFrameLowering::hasFP(), llvm::ARMFunctionInfo::hasStackFrame(), llvm_unreachable, MBB, MI, TII, and TRI.

getArgumentStackToRestore()

static int getArgumentStackToRestore ( MachineFunction &  MF, MachineBasicBlock &  MBB  )

static

Definition at line 388 of file ARMFrameLowering.cpp.

References llvm::MachineBasicBlock::end(), llvm::ARMFunctionInfo::getArgumentStackToRestore(), llvm::MachineOperand::getImm(), llvm::MachineFunction::getInfo(), llvm::MachineBasicBlock::getLastNonDebugInstr(), MBB, and MBBI.

getMaxFPOffset()

static int getMaxFPOffset ( const ARMSubtarget &  STI, const ARMFunctionInfo &  AFI, const MachineFunction &  MF  )

static

We need the offset of the frame pointer relative to other MachineFrameInfo offsets which are encoded relative to SP at function begin.

See also emitPrologue() for how the FP is set up. Unfortunately we cannot determine this value in determineCalleeSaves() yet as assignCalleeSavedSpillSlots() hasn't run at this point. Instead we use this to produce a conservative estimate that we check in an assert() later.

Definition at line 865 of file ARMFrameLowering.cpp.

References llvm::ARMFunctionInfo::getArgRegsSaveSize(), llvm::ARMSubtarget::getPushPopSplitVariation(), llvm::ARMFunctionInfo::isCmseNSEntryFunction(), llvm::ARMFunctionInfo::isThumb1OnlyFunction(), llvm::ARMSubtarget::SplitR11AAPCSSignRA, and llvm::ARMSubtarget::SplitR11WindowsSEH.

Referenced by llvm::ARMFrameLowering::determineCalleeSaves(), and llvm::ARMFrameLowering::emitPrologue().

getSpillArea()

SpillArea getSpillArea	(	Register	Reg,
		ARMSubtarget::PushPopSplitVariation	Variation,
		unsigned	NumAlignedDPRCS2Regs,
		const ARMBaseRegisterInfo *	RegInfo
	)

Get the spill area that Reg should be saved into in the prologue.

Definition at line 185 of file ARMFrameLowering.cpp.

References llvm::ARM::D16, llvm::dbgs(), DPRCS1, DPRCS2, FPCXT, GPRCS1, GPRCS2, GPRCS3, llvm_unreachable, llvm::printReg(), llvm::ARMSubtarget::SplitR11AAPCSSignRA, llvm::ARMSubtarget::SplitR11WindowsSEH, and llvm::ARMSubtarget::SplitR7.

Referenced by llvm::ARMFrameLowering::emitPrologue(), llvm::ARMFrameLowering::restoreCalleeSavedRegisters(), and llvm::ARMFrameLowering::spillCalleeSavedRegisters().

initMBBRange()

static MachineBasicBlock::iterator initMBBRange ( MachineBasicBlock &  MBB, const MachineBasicBlock::iterator &  MBBI  )

static

Definition at line 641 of file ARMFrameLowering.cpp.

References llvm::MachineBasicBlock::begin(), MBB, and MBBI.

Referenced by llvm::ARMFrameLowering::emitEpilogue().

insertSEH()

static MachineBasicBlock::iterator insertSEH ( MachineBasicBlock::iterator  MBBI, const TargetInstrInfo &  TII, unsigned  Flags  )

static

Definition at line 427 of file ARMFrameLowering.cpp.

References llvm::MachineInstrBuilder::add(), llvm::MachineInstrBuilder::addImm(), llvm::BuildMI(), DL, llvm::drop_begin(), llvm::MachineBasicBlock::erase(), llvm::First, llvm::MachineInstr::FrameDestroy, llvm::MachineInstr::FrameSetup, llvm::MachineBasicBlock::getParent(), llvm::MachineOperand::getReg(), llvm::ARMSubtarget::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), llvm::MachineBasicBlock::insertAfter(), llvm::MachineOperand::isImplicit(), llvm::MachineOperand::isReg(), llvm::Last, llvm_unreachable, MBB, MBBI, llvm::MachineInstr::NoMerge, llvm::report_fatal_error(), llvm::MachineInstrBuilder::setMIFlags(), llvm::t1CondCodeOp(), and TII.

Referenced by insertSEHRange().

insertSEHRange()

static void insertSEHRange ( MachineBasicBlock &  MBB, MachineBasicBlock::iterator  Start, const MachineBasicBlock::iterator &  End, const ARMBaseInstrInfo &  TII, unsigned  MIFlags  )

static

Definition at line 647 of file ARMFrameLowering.cpp.

References llvm::MachineBasicBlock::begin(), End, insertSEH(), llvm::isSEHInstruction(), MBB, MI, and TII.

Referenced by llvm::ARMFrameLowering::emitEpilogue(), and llvm::ARMFrameLowering::emitPrologue().

needsWinCFI()

static bool needsWinCFI ( const MachineFunction &  MF )

static

Definition at line 419 of file ARMFrameLowering.cpp.

References F, llvm::MachineFunction::getFunction(), llvm::TargetMachine::getMCAsmInfo(), llvm::MachineFunction::getTarget(), and llvm::MCAsmInfo::usesWindowsCFI().

sizeOfSPAdjustment()

static int sizeOfSPAdjustment ( const MachineInstr &  MI )

static

Definition at line 694 of file ARMFrameLowering.cpp.

References llvm::count(), llvm_unreachable, MI, and RegSize.

Referenced by llvm::ARMFrameLowering::emitPrologue().

skipAlignedDPRCS2Spills()

static MachineBasicBlock::iterator skipAlignedDPRCS2Spills ( MachineBasicBlock::iterator  MI, unsigned  NumAlignedDPRCS2Regs  )

static

Skip past the code inserted by emitAlignedDPRCS2Spills, and return an iterator to the following instruction.

Definition at line 1984 of file ARMFrameLowering.cpp.

References assert(), and MI.

Referenced by llvm::ARMFrameLowering::emitPrologue().

WindowsRequiresStackProbe()

static bool WindowsRequiresStackProbe ( const MachineFunction &  MF, size_t  StackSizeInBytes  )

static

Definition at line 719 of file ARMFrameLowering.cpp.

References F, llvm::MachineFunction::getFrameInfo(), llvm::MachineFunction::getFunction(), and llvm::MachineFrameInfo::getStackProtectorIndex().

Referenced by llvm::ARMFrameLowering::determineCalleeSaves(), and llvm::ARMFrameLowering::emitPrologue().

Variable Documentation

kSplitStackAvailable

const uint64_t kSplitStackAvailable = 256

static

Definition at line 3129 of file ARMFrameLowering.cpp.

Referenced by llvm::ARMFrameLowering::adjustForSegmentedStacks(), and llvm::X86FrameLowering::adjustForSegmentedStacks().

SpillAlignedNEONRegs

cl::opt< bool > SpillAlignedNEONRegs("align-neon-spills", cl::Hidden, cl::init(true), cl::desc("Align ARM NEON spills in prolog and epilog")) ( "align-neon-spills"  , cl::Hidden  , cl::init(true)  , cl::desc("Align ARM NEON spills in prolog and epilog")    )

static

Referenced by checkNumAlignedDPRCS2Regs().