lib/Target/XCore/XCoreFrameLowering.cpp - llvm - Git at Google

 //===-- XCoreFrameLowering.cpp - Frame info for XCore Target --------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file contains XCore frame information that doesn't fit anywhere else
 // cleanly...
 //
 //===----------------------------------------------------------------------===//

 #include "XCoreFrameLowering.h"
 #include "XCore.h"
 #include "XCoreInstrInfo.h"
 #include "XCoreMachineFunctionInfo.h"
 #include "llvm/Function.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/ErrorHandling.h"

 using namespace llvm;

 // helper functions. FIXME: Eliminate.
 static inline bool isImmUs(unsigned val) {
   return val <= 11;
 }

 static inline bool isImmU6(unsigned val) {
   return val < (1 << 6);
 }

 static inline bool isImmU16(unsigned val) {
   return val < (1 << 16);
 }

 static void loadFromStack(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator I,
                           unsigned DstReg, int Offset, DebugLoc dl,
                           const TargetInstrInfo &TII) {
   assert(Offset%4 == 0 && "Misaligned stack offset");
   Offset/=4;
   bool isU6 = isImmU6(Offset);
   if (!isU6 && !isImmU16(Offset))
     report_fatal_error("loadFromStack offset too big " + Twine(Offset));
   int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
   BuildMI(MBB, I, dl, TII.get(Opcode), DstReg)
     .addImm(Offset);
 }


 static void storeToStack(MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator I,
                          unsigned SrcReg, int Offset, DebugLoc dl,
                          const TargetInstrInfo &TII) {
   assert(Offset%4 == 0 && "Misaligned stack offset");
   Offset/=4;
   bool isU6 = isImmU6(Offset);
   if (!isU6 && !isImmU16(Offset))
     report_fatal_error("storeToStack offset too big " + Twine(Offset));
   int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
   BuildMI(MBB, I, dl, TII.get(Opcode))
     .addReg(SrcReg)
     .addImm(Offset);
 }


 //===----------------------------------------------------------------------===//
 // XCoreFrameLowering:
 //===----------------------------------------------------------------------===//

 XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
   : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 4, 0),
     STI(sti) {
   // Do nothing
 }

 bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
   return MF.getTarget().Options.DisableFramePointerElim(MF) ||
     MF.getFrameInfo()->hasVarSizedObjects();
 }

 void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
   MachineBasicBlock::iterator MBBI = MBB.begin();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MachineModuleInfo *MMI = &MF.getMMI();
   const XCoreInstrInfo &TII =
     *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
   XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
   DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

   bool FP = hasFP(MF);
   bool Nested = MF.getFunction()->
                 getAttributes().hasAttrSomewhere(Attribute::Nest);

   if (Nested) {
     loadFromStack(MBB, MBBI, XCore::R11, 0, dl, TII);
   }

   // Work out frame sizes.
   int FrameSize = MFI->getStackSize();
   assert(FrameSize%4 == 0 && "Misaligned frame size");
   FrameSize/=4;

   bool isU6 = isImmU6(FrameSize);

   if (!isU6 && !isImmU16(FrameSize)) {
     // FIXME could emit multiple instructions.
     report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
   }
   bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(MF);

   // Do we need to allocate space on the stack?
   if (FrameSize) {
     bool saveLR = XFI->getUsesLR();
     bool LRSavedOnEntry = false;
     int Opcode;
     if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
       Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
       MBB.addLiveIn(XCore::LR);
       saveLR = false;
       LRSavedOnEntry = true;
     } else {
       Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
     }
     BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);

     if (emitFrameMoves) {
       std::vector<MachineMove> &Moves = MMI->getFrameMoves();

       // Show update of SP.
       MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
       BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);

       MachineLocation SPDst(MachineLocation::VirtualFP);
       MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
       Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));

       if (LRSavedOnEntry) {
         MachineLocation CSDst(MachineLocation::VirtualFP, 0);
         MachineLocation CSSrc(XCore::LR);
         Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
       }
     }
     if (saveLR) {
       int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
       storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
       MBB.addLiveIn(XCore::LR);

       if (emitFrameMoves) {
         MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
         BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
         MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
         MachineLocation CSSrc(XCore::LR);
         MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
       }
     }
   }

   if (FP) {
     // Save R10 to the stack.
     int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
     storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
     // R10 is live-in. It is killed at the spill.
     MBB.addLiveIn(XCore::R10);
     if (emitFrameMoves) {
       MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
       BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
       MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
       MachineLocation CSSrc(XCore::R10);
       MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
     }
     // Set the FP from the SP.
     unsigned FramePtr = XCore::R10;
     BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
       .addImm(0);
     if (emitFrameMoves) {
       // Show FP is now valid.
       MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
       BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
       MachineLocation SPDst(FramePtr);
       MachineLocation SPSrc(MachineLocation::VirtualFP);
       MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
     }
   }

   if (emitFrameMoves) {
     // Frame moves for callee saved.
     std::vector<MachineMove> &Moves = MMI->getFrameMoves();
     std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
         XFI->getSpillLabels();
     for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
       MCSymbol *SpillLabel = SpillLabels[I].first;
       CalleeSavedInfo &CSI = SpillLabels[I].second;
       int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
       unsigned Reg = CSI.getReg();
       MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
       MachineLocation CSSrc(Reg);
       Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
     }
   }
 }

 void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
                                      MachineBasicBlock &MBB) const {
   MachineFrameInfo *MFI            = MF.getFrameInfo();
   MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   const XCoreInstrInfo &TII =
     *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
   DebugLoc dl = MBBI->getDebugLoc();

   bool FP = hasFP(MF);
   if (FP) {
     // Restore the stack pointer.
     unsigned FramePtr = XCore::R10;
     BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
       .addReg(FramePtr);
   }

   // Work out frame sizes.
   int FrameSize = MFI->getStackSize();

   assert(FrameSize%4 == 0 && "Misaligned frame size");

   FrameSize/=4;

   bool isU6 = isImmU6(FrameSize);

   if (!isU6 && !isImmU16(FrameSize)) {
     // FIXME could emit multiple instructions.
     report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
   }

   if (FrameSize) {
     XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();

     if (FP) {
       // Restore R10
       int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
       FPSpillOffset += FrameSize*4;
       loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
     }
     bool restoreLR = XFI->getUsesLR();
     if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
       int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
       LRSpillOffset += FrameSize*4;
       loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
       restoreLR = false;
     }
     if (restoreLR) {
       // Fold prologue into return instruction
       assert(MBBI->getOpcode() == XCore::RETSP_u6
         || MBBI->getOpcode() == XCore::RETSP_lu6);
       int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
       BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
       MBB.erase(MBBI);
     } else {
       int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
       BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
     }
   }
 }

 bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
                                                MachineBasicBlock::iterator MI,
                                         const std::vector<CalleeSavedInfo> &CSI,
                                           const TargetRegisterInfo *TRI) const {
   if (CSI.empty())
     return true;

   MachineFunction *MF = MBB.getParent();
   const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();

   XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
   bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);

   DebugLoc DL;
   if (MI != MBB.end()) DL = MI->getDebugLoc();

   for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
                                                     it != CSI.end(); ++it) {
     // Add the callee-saved register as live-in. It's killed at the spill.
     MBB.addLiveIn(it->getReg());

     unsigned Reg = it->getReg();
     const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
     TII.storeRegToStackSlot(MBB, MI, Reg, true,
                             it->getFrameIdx(), RC, TRI);
     if (emitFrameMoves) {
       MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
       BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
       XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
     }
   }
   return true;
 }

 bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
                                                  MachineBasicBlock::iterator MI,
                                         const std::vector<CalleeSavedInfo> &CSI,
                                             const TargetRegisterInfo *TRI) const{
   MachineFunction *MF = MBB.getParent();
   const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();

   bool AtStart = MI == MBB.begin();
   MachineBasicBlock::iterator BeforeI = MI;
   if (!AtStart)
     --BeforeI;
   for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
                                                     it != CSI.end(); ++it) {
     unsigned Reg = it->getReg();
     const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
     TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
                              RC, TRI);
     assert(MI != MBB.begin() &&
            "loadRegFromStackSlot didn't insert any code!");
     // Insert in reverse order.  loadRegFromStackSlot can insert multiple
     // instructions.
     if (AtStart)
       MI = MBB.begin();
     else {
       MI = BeforeI;
       ++MI;
     }
   }
   return true;
 }

 void
 XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
                                                      RegScavenger *RS) const {
   MachineFrameInfo *MFI = MF.getFrameInfo();
   const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
   bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
   const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
   XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
   if (LRUsed) {
     MF.getRegInfo().setPhysRegUnused(XCore::LR);

     bool isVarArg = MF.getFunction()->isVarArg();
     int FrameIdx;
     if (! isVarArg) {
       // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
       FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
     } else {
       FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
                                         false);
     }
     XFI->setUsesLR(FrameIdx);
     XFI->setLRSpillSlot(FrameIdx);
   }
   if (RegInfo->requiresRegisterScavenging(MF)) {
     // Reserve a slot close to SP or frame pointer.
     RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
                                                        RC->getAlignment(),
                                                        false));
   }
   if (hasFP(MF)) {
     // A callee save register is used to hold the FP.
     // This needs saving / restoring in the epilogue / prologue.
     XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
                                                RC->getAlignment(),
                                                false));
   }
 }

 void XCoreFrameLowering::
 processFunctionBeforeFrameFinalized(MachineFunction &MF) const {

 }
	//===-- XCoreFrameLowering.cpp - Frame info for XCore Target --------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file contains XCore frame information that doesn't fit anywhere else
	// cleanly...
	//
	//===----------------------------------------------------------------------===//

	#include "XCoreFrameLowering.h"
	#include "XCore.h"
	#include "XCoreInstrInfo.h"
	#include "XCoreMachineFunctionInfo.h"
	#include "llvm/Function.h"
	#include "llvm/CodeGen/MachineFrameInfo.h"
	#include "llvm/CodeGen/MachineFunction.h"
	#include "llvm/CodeGen/MachineInstrBuilder.h"
	#include "llvm/CodeGen/MachineModuleInfo.h"
	#include "llvm/CodeGen/MachineRegisterInfo.h"
	#include "llvm/CodeGen/RegisterScavenging.h"
	#include "llvm/Target/TargetData.h"
	#include "llvm/Target/TargetOptions.h"
	#include "llvm/Support/ErrorHandling.h"

	using namespace llvm;

	// helper functions. FIXME: Eliminate.
	static inline bool isImmUs(unsigned val) {
	return val <= 11;
	}

	static inline bool isImmU6(unsigned val) {
	return val < (1 << 6);
	}

	static inline bool isImmU16(unsigned val) {
	return val < (1 << 16);
	}

	static void loadFromStack(MachineBasicBlock &MBB,
	MachineBasicBlock::iterator I,
	unsigned DstReg, int Offset, DebugLoc dl,
	const TargetInstrInfo &TII) {
	assert(Offset%4 == 0 && "Misaligned stack offset");
	Offset/=4;
	bool isU6 = isImmU6(Offset);
	if (!isU6 && !isImmU16(Offset))
	report_fatal_error("loadFromStack offset too big " + Twine(Offset));
	int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
	BuildMI(MBB, I, dl, TII.get(Opcode), DstReg)
	.addImm(Offset);
	}


	static void storeToStack(MachineBasicBlock &MBB,
	MachineBasicBlock::iterator I,
	unsigned SrcReg, int Offset, DebugLoc dl,
	const TargetInstrInfo &TII) {
	assert(Offset%4 == 0 && "Misaligned stack offset");
	Offset/=4;
	bool isU6 = isImmU6(Offset);
	if (!isU6 && !isImmU16(Offset))
	report_fatal_error("storeToStack offset too big " + Twine(Offset));
	int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
	BuildMI(MBB, I, dl, TII.get(Opcode))
	.addReg(SrcReg)
	.addImm(Offset);
	}


	//===----------------------------------------------------------------------===//
	// XCoreFrameLowering:
	//===----------------------------------------------------------------------===//

	XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
	: TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 4, 0),
	STI(sti) {
	// Do nothing
	}

	bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
	return MF.getTarget().Options.DisableFramePointerElim(MF) \|\|
	MF.getFrameInfo()->hasVarSizedObjects();
	}

	void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
	MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
	MachineBasicBlock::iterator MBBI = MBB.begin();
	MachineFrameInfo *MFI = MF.getFrameInfo();
	MachineModuleInfo *MMI = &MF.getMMI();
	const XCoreInstrInfo &TII =
	static_cast<const XCoreInstrInfo>(MF.getTarget().getInstrInfo());
	XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
	DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

	bool FP = hasFP(MF);
	bool Nested = MF.getFunction()->
	getAttributes().hasAttrSomewhere(Attribute::Nest);

	if (Nested) {
	loadFromStack(MBB, MBBI, XCore::R11, 0, dl, TII);
	}

	// Work out frame sizes.
	int FrameSize = MFI->getStackSize();
	assert(FrameSize%4 == 0 && "Misaligned frame size");
	FrameSize/=4;

	bool isU6 = isImmU6(FrameSize);

	if (!isU6 && !isImmU16(FrameSize)) {
	// FIXME could emit multiple instructions.
	report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
	}
	bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(MF);

	// Do we need to allocate space on the stack?
	if (FrameSize) {
	bool saveLR = XFI->getUsesLR();
	bool LRSavedOnEntry = false;
	int Opcode;
	if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
	Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
	MBB.addLiveIn(XCore::LR);
	saveLR = false;
	LRSavedOnEntry = true;
	} else {
	Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
	}
	BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);

	if (emitFrameMoves) {
	std::vector<MachineMove> &Moves = MMI->getFrameMoves();

	// Show update of SP.
	MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
	BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);

	MachineLocation SPDst(MachineLocation::VirtualFP);
	MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
	Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));

	if (LRSavedOnEntry) {
	MachineLocation CSDst(MachineLocation::VirtualFP, 0);
	MachineLocation CSSrc(XCore::LR);
	Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
	}
	}
	if (saveLR) {
	int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
	storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
	MBB.addLiveIn(XCore::LR);

	if (emitFrameMoves) {
	MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
	BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
	MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
	MachineLocation CSSrc(XCore::LR);
	MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
	}
	}
	}

	if (FP) {
	// Save R10 to the stack.
	int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
	storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
	// R10 is live-in. It is killed at the spill.
	MBB.addLiveIn(XCore::R10);
	if (emitFrameMoves) {
	MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
	BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
	MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
	MachineLocation CSSrc(XCore::R10);
	MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
	}
	// Set the FP from the SP.
	unsigned FramePtr = XCore::R10;
	BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
	.addImm(0);
	if (emitFrameMoves) {
	// Show FP is now valid.
	MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
	BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
	MachineLocation SPDst(FramePtr);
	MachineLocation SPSrc(MachineLocation::VirtualFP);
	MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
	}
	}

	if (emitFrameMoves) {
	// Frame moves for callee saved.
	std::vector<MachineMove> &Moves = MMI->getFrameMoves();
	std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
	XFI->getSpillLabels();
	for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
	MCSymbol *SpillLabel = SpillLabels[I].first;
	CalleeSavedInfo &CSI = SpillLabels[I].second;
	int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
	unsigned Reg = CSI.getReg();
	MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
	MachineLocation CSSrc(Reg);
	Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
	}
	}
	}

	void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
	MachineBasicBlock &MBB) const {
	MachineFrameInfo *MFI = MF.getFrameInfo();
	MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
	const XCoreInstrInfo &TII =
	static_cast<const XCoreInstrInfo>(MF.getTarget().getInstrInfo());
	DebugLoc dl = MBBI->getDebugLoc();

	bool FP = hasFP(MF);
	if (FP) {
	// Restore the stack pointer.
	unsigned FramePtr = XCore::R10;
	BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
	.addReg(FramePtr);
	}

	// Work out frame sizes.
	int FrameSize = MFI->getStackSize();

	assert(FrameSize%4 == 0 && "Misaligned frame size");

	FrameSize/=4;

	bool isU6 = isImmU6(FrameSize);

	if (!isU6 && !isImmU16(FrameSize)) {
	// FIXME could emit multiple instructions.
	report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
	}

	if (FrameSize) {
	XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();

	if (FP) {
	// Restore R10
	int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
	FPSpillOffset += FrameSize*4;
	loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
	}
	bool restoreLR = XFI->getUsesLR();
	if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
	int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
	LRSpillOffset += FrameSize*4;
	loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
	restoreLR = false;
	}
	if (restoreLR) {
	// Fold prologue into return instruction
	assert(MBBI->getOpcode() == XCore::RETSP_u6
	\|\| MBBI->getOpcode() == XCore::RETSP_lu6);
	int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
	BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
	MBB.erase(MBBI);
	} else {
	int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
	BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
	}
	}
	}

	bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
	MachineBasicBlock::iterator MI,
	const std::vector<CalleeSavedInfo> &CSI,
	const TargetRegisterInfo *TRI) const {
	if (CSI.empty())
	return true;

	MachineFunction *MF = MBB.getParent();
	const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();

	XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
	bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);

	DebugLoc DL;
	if (MI != MBB.end()) DL = MI->getDebugLoc();

	for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
	it != CSI.end(); ++it) {
	// Add the callee-saved register as live-in. It's killed at the spill.
	MBB.addLiveIn(it->getReg());

	unsigned Reg = it->getReg();
	const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
	TII.storeRegToStackSlot(MBB, MI, Reg, true,
	it->getFrameIdx(), RC, TRI);
	if (emitFrameMoves) {
	MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
	BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
	XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
	}
	}
	return true;
	}

	bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
	MachineBasicBlock::iterator MI,
	const std::vector<CalleeSavedInfo> &CSI,
	const TargetRegisterInfo *TRI) const{
	MachineFunction *MF = MBB.getParent();
	const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();

	bool AtStart = MI == MBB.begin();
	MachineBasicBlock::iterator BeforeI = MI;
	if (!AtStart)
	--BeforeI;
	for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
	it != CSI.end(); ++it) {
	unsigned Reg = it->getReg();
	const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
	TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
	RC, TRI);
	assert(MI != MBB.begin() &&
	"loadRegFromStackSlot didn't insert any code!");
	// Insert in reverse order. loadRegFromStackSlot can insert multiple
	// instructions.
	if (AtStart)
	MI = MBB.begin();
	else {
	MI = BeforeI;
	++MI;
	}
	}
	return true;
	}

	void
	XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
	RegScavenger *RS) const {
	MachineFrameInfo *MFI = MF.getFrameInfo();
	const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
	bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
	const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
	XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
	if (LRUsed) {
	MF.getRegInfo().setPhysRegUnused(XCore::LR);

	bool isVarArg = MF.getFunction()->isVarArg();
	int FrameIdx;
	if (! isVarArg) {
	// A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
	FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
	} else {
	FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
	false);
	}
	XFI->setUsesLR(FrameIdx);
	XFI->setLRSpillSlot(FrameIdx);
	}
	if (RegInfo->requiresRegisterScavenging(MF)) {
	// Reserve a slot close to SP or frame pointer.
	RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
	RC->getAlignment(),
	false));
	}
	if (hasFP(MF)) {
	// A callee save register is used to hold the FP.
	// This needs saving / restoring in the epilogue / prologue.
	XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
	RC->getAlignment(),
	false));
	}
	}

	void XCoreFrameLowering::
	processFunctionBeforeFrameFinalized(MachineFunction &MF) const {

	}