LLVM API Documentation

SPURegisterInfo.cpp

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00001 //===- SPURegisterInfo.cpp - Cell SPU Register Information ----------------===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file is distributed under the University of Illinois Open Source
00006 // License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file contains the Cell implementation of the TargetRegisterInfo class.
00011 //
00012 //===----------------------------------------------------------------------===//
00013 
00014 #define DEBUG_TYPE "reginfo"
00015 #include "SPU.h"
00016 #include "SPURegisterInfo.h"
00017 #include "SPURegisterNames.h"
00018 #include "SPUInstrBuilder.h"
00019 #include "SPUSubtarget.h"
00020 #include "SPUMachineFunction.h"
00021 #include "SPUFrameInfo.h"
00022 #include "llvm/Constants.h"
00023 #include "llvm/Type.h"
00024 #include "llvm/CodeGen/ValueTypes.h"
00025 #include "llvm/CodeGen/MachineInstrBuilder.h"
00026 #include "llvm/CodeGen/MachineModuleInfo.h"
00027 #include "llvm/CodeGen/MachineFunction.h"
00028 #include "llvm/CodeGen/MachineFrameInfo.h"
00029 #include "llvm/CodeGen/MachineLocation.h"
00030 #include "llvm/CodeGen/MachineRegisterInfo.h"
00031 #include "llvm/CodeGen/ValueTypes.h"
00032 #include "llvm/Target/TargetFrameInfo.h"
00033 #include "llvm/Target/TargetInstrInfo.h"
00034 #include "llvm/Target/TargetMachine.h"
00035 #include "llvm/Target/TargetOptions.h"
00036 #include "llvm/Support/CommandLine.h"
00037 #include "llvm/Support/Debug.h"
00038 #include "llvm/Support/MathExtras.h"
00039 #include "llvm/ADT/BitVector.h"
00040 #include "llvm/ADT/STLExtras.h"
00041 #include <cstdlib>
00042 
00043 using namespace llvm;
00044 
00045 /// getRegisterNumbering - Given the enum value for some register, e.g.
00046 /// PPC::F14, return the number that it corresponds to (e.g. 14).
00047 unsigned SPURegisterInfo::getRegisterNumbering(unsigned RegEnum) {
00048   using namespace SPU;
00049   switch (RegEnum) {
00050   case SPU::R0: return 0;
00051   case SPU::R1: return 1;
00052   case SPU::R2: return 2;
00053   case SPU::R3: return 3;
00054   case SPU::R4: return 4;
00055   case SPU::R5: return 5;
00056   case SPU::R6: return 6;
00057   case SPU::R7: return 7;
00058   case SPU::R8: return 8;
00059   case SPU::R9: return 9;
00060   case SPU::R10: return 10;
00061   case SPU::R11: return 11;
00062   case SPU::R12: return 12;
00063   case SPU::R13: return 13;
00064   case SPU::R14: return 14;
00065   case SPU::R15: return 15;
00066   case SPU::R16: return 16;
00067   case SPU::R17: return 17;
00068   case SPU::R18: return 18;
00069   case SPU::R19: return 19;
00070   case SPU::R20: return 20;
00071   case SPU::R21: return 21;
00072   case SPU::R22: return 22;
00073   case SPU::R23: return 23;
00074   case SPU::R24: return 24;
00075   case SPU::R25: return 25;
00076   case SPU::R26: return 26;
00077   case SPU::R27: return 27;
00078   case SPU::R28: return 28;
00079   case SPU::R29: return 29;
00080   case SPU::R30: return 30;
00081   case SPU::R31: return 31;
00082   case SPU::R32: return 32;
00083   case SPU::R33: return 33;
00084   case SPU::R34: return 34;
00085   case SPU::R35: return 35;
00086   case SPU::R36: return 36;
00087   case SPU::R37: return 37;
00088   case SPU::R38: return 38;
00089   case SPU::R39: return 39;
00090   case SPU::R40: return 40;
00091   case SPU::R41: return 41;
00092   case SPU::R42: return 42;
00093   case SPU::R43: return 43;
00094   case SPU::R44: return 44;
00095   case SPU::R45: return 45;
00096   case SPU::R46: return 46;
00097   case SPU::R47: return 47;
00098   case SPU::R48: return 48;
00099   case SPU::R49: return 49;
00100   case SPU::R50: return 50;
00101   case SPU::R51: return 51;
00102   case SPU::R52: return 52;
00103   case SPU::R53: return 53;
00104   case SPU::R54: return 54;
00105   case SPU::R55: return 55;
00106   case SPU::R56: return 56;
00107   case SPU::R57: return 57;
00108   case SPU::R58: return 58;
00109   case SPU::R59: return 59;
00110   case SPU::R60: return 60;
00111   case SPU::R61: return 61;
00112   case SPU::R62: return 62;
00113   case SPU::R63: return 63;
00114   case SPU::R64: return 64;
00115   case SPU::R65: return 65;
00116   case SPU::R66: return 66;
00117   case SPU::R67: return 67;
00118   case SPU::R68: return 68;
00119   case SPU::R69: return 69;
00120   case SPU::R70: return 70;
00121   case SPU::R71: return 71;
00122   case SPU::R72: return 72;
00123   case SPU::R73: return 73;
00124   case SPU::R74: return 74;
00125   case SPU::R75: return 75;
00126   case SPU::R76: return 76;
00127   case SPU::R77: return 77;
00128   case SPU::R78: return 78;
00129   case SPU::R79: return 79;
00130   case SPU::R80: return 80;
00131   case SPU::R81: return 81;
00132   case SPU::R82: return 82;
00133   case SPU::R83: return 83;
00134   case SPU::R84: return 84;
00135   case SPU::R85: return 85;
00136   case SPU::R86: return 86;
00137   case SPU::R87: return 87;
00138   case SPU::R88: return 88;
00139   case SPU::R89: return 89;
00140   case SPU::R90: return 90;
00141   case SPU::R91: return 91;
00142   case SPU::R92: return 92;
00143   case SPU::R93: return 93;
00144   case SPU::R94: return 94;
00145   case SPU::R95: return 95;
00146   case SPU::R96: return 96;
00147   case SPU::R97: return 97;
00148   case SPU::R98: return 98;
00149   case SPU::R99: return 99;
00150   case SPU::R100: return 100;
00151   case SPU::R101: return 101;
00152   case SPU::R102: return 102;
00153   case SPU::R103: return 103;
00154   case SPU::R104: return 104;
00155   case SPU::R105: return 105;
00156   case SPU::R106: return 106;
00157   case SPU::R107: return 107;
00158   case SPU::R108: return 108;
00159   case SPU::R109: return 109;
00160   case SPU::R110: return 110;
00161   case SPU::R111: return 111;
00162   case SPU::R112: return 112;
00163   case SPU::R113: return 113;
00164   case SPU::R114: return 114;
00165   case SPU::R115: return 115;
00166   case SPU::R116: return 116;
00167   case SPU::R117: return 117;
00168   case SPU::R118: return 118;
00169   case SPU::R119: return 119;
00170   case SPU::R120: return 120;
00171   case SPU::R121: return 121;
00172   case SPU::R122: return 122;
00173   case SPU::R123: return 123;
00174   case SPU::R124: return 124;
00175   case SPU::R125: return 125;
00176   case SPU::R126: return 126;
00177   case SPU::R127: return 127;
00178   default:
00179     cerr << "Unhandled reg in SPURegisterInfo::getRegisterNumbering!\n";
00180     abort();
00181   }
00182 }
00183 
00184 SPURegisterInfo::SPURegisterInfo(const SPUSubtarget &subtarget,
00185                                  const TargetInstrInfo &tii) :
00186   SPUGenRegisterInfo(SPU::ADJCALLSTACKDOWN, SPU::ADJCALLSTACKUP),
00187   Subtarget(subtarget),
00188   TII(tii)
00189 {
00190 }
00191 
00192 // SPU's 128-bit registers used for argument passing:
00193 static const unsigned SPU_ArgRegs[] = {
00194   SPU::R3,  SPU::R4,  SPU::R5,  SPU::R6,  SPU::R7,  SPU::R8,  SPU::R9,
00195   SPU::R10, SPU::R11, SPU::R12, SPU::R13, SPU::R14, SPU::R15, SPU::R16,
00196   SPU::R17, SPU::R18, SPU::R19, SPU::R20, SPU::R21, SPU::R22, SPU::R23,
00197   SPU::R24, SPU::R25, SPU::R26, SPU::R27, SPU::R28, SPU::R29, SPU::R30,
00198   SPU::R31, SPU::R32, SPU::R33, SPU::R34, SPU::R35, SPU::R36, SPU::R37,
00199   SPU::R38, SPU::R39, SPU::R40, SPU::R41, SPU::R42, SPU::R43, SPU::R44,
00200   SPU::R45, SPU::R46, SPU::R47, SPU::R48, SPU::R49, SPU::R50, SPU::R51,
00201   SPU::R52, SPU::R53, SPU::R54, SPU::R55, SPU::R56, SPU::R57, SPU::R58,
00202   SPU::R59, SPU::R60, SPU::R61, SPU::R62, SPU::R63, SPU::R64, SPU::R65,
00203   SPU::R66, SPU::R67, SPU::R68, SPU::R69, SPU::R70, SPU::R71, SPU::R72,
00204   SPU::R73, SPU::R74, SPU::R75, SPU::R76, SPU::R77, SPU::R78, SPU::R79
00205 };
00206 
00207 const unsigned *
00208 SPURegisterInfo::getArgRegs()
00209 {
00210   return SPU_ArgRegs;
00211 }
00212 
00213 unsigned
00214 SPURegisterInfo::getNumArgRegs()
00215 {
00216   return sizeof(SPU_ArgRegs) / sizeof(SPU_ArgRegs[0]);
00217 }
00218 
00219 const unsigned *
00220 SPURegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const
00221 {
00222   // Cell ABI calling convention
00223   static const unsigned SPU_CalleeSaveRegs[] = {
00224     SPU::R80, SPU::R81, SPU::R82, SPU::R83,
00225     SPU::R84, SPU::R85, SPU::R86, SPU::R87,
00226     SPU::R88, SPU::R89, SPU::R90, SPU::R91,
00227     SPU::R92, SPU::R93, SPU::R94, SPU::R95,
00228     SPU::R96, SPU::R97, SPU::R98, SPU::R99,
00229     SPU::R100, SPU::R101, SPU::R102, SPU::R103,
00230     SPU::R104, SPU::R105, SPU::R106, SPU::R107,
00231     SPU::R108, SPU::R109, SPU::R110, SPU::R111,
00232     SPU::R112, SPU::R113, SPU::R114, SPU::R115,
00233     SPU::R116, SPU::R117, SPU::R118, SPU::R119,
00234     SPU::R120, SPU::R121, SPU::R122, SPU::R123,
00235     SPU::R124, SPU::R125, SPU::R126, SPU::R127,
00236     SPU::R2,    /* environment pointer */
00237     SPU::R1,    /* stack pointer */
00238     SPU::R0,    /* link register */
00239     0 /* end */
00240   };
00241 
00242   return SPU_CalleeSaveRegs;
00243 }
00244 
00245 const TargetRegisterClass* const*
00246 SPURegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const
00247 {
00248   // Cell ABI Calling Convention
00249   static const TargetRegisterClass * const SPU_CalleeSaveRegClasses[] = {
00250     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00251     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00252     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00253     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00254     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00255     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00256     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00257     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00258     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00259     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00260     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00261     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00262     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00263     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00264     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00265     &SPU::GPRCRegClass, &SPU::GPRCRegClass, &SPU::GPRCRegClass,
00266     &SPU::GPRCRegClass, /* environment pointer */
00267     &SPU::GPRCRegClass, /* stack pointer */
00268     &SPU::GPRCRegClass, /* link register */
00269     0 /* end */
00270   };
00271 
00272   return SPU_CalleeSaveRegClasses;
00273 }
00274 
00275 /*!
00276  R0 (link register), R1 (stack pointer) and R2 (environment pointer -- this is
00277  generally unused) are the Cell's reserved registers
00278  */
00279 BitVector SPURegisterInfo::getReservedRegs(const MachineFunction &MF) const {
00280   BitVector Reserved(getNumRegs());
00281   Reserved.set(SPU::R0);                // LR
00282   Reserved.set(SPU::R1);                // SP
00283   Reserved.set(SPU::R2);                // environment pointer
00284   return Reserved;
00285 }
00286 
00287 //===----------------------------------------------------------------------===//
00288 // Stack Frame Processing methods
00289 //===----------------------------------------------------------------------===//
00290 
00291 // needsFP - Return true if the specified function should have a dedicated frame
00292 // pointer register.  This is true if the function has variable sized allocas or
00293 // if frame pointer elimination is disabled.
00294 //
00295 static bool needsFP(const MachineFunction &MF) {
00296   const MachineFrameInfo *MFI = MF.getFrameInfo();
00297   return NoFramePointerElim || MFI->hasVarSizedObjects();
00298 }
00299 
00300 //--------------------------------------------------------------------------
00301 // hasFP - Return true if the specified function actually has a dedicated frame
00302 // pointer register.  This is true if the function needs a frame pointer and has
00303 // a non-zero stack size.
00304 bool
00305 SPURegisterInfo::hasFP(const MachineFunction &MF) const {
00306   const MachineFrameInfo *MFI = MF.getFrameInfo();
00307   return MFI->getStackSize() && needsFP(MF);
00308 }
00309 
00310 //--------------------------------------------------------------------------
00311 void
00312 SPURegisterInfo::eliminateCallFramePseudoInstr(MachineFunction &MF,
00313                                                MachineBasicBlock &MBB,
00314                                                MachineBasicBlock::iterator I)
00315   const
00316 {
00317   // Simply discard ADJCALLSTACKDOWN, ADJCALLSTACKUP instructions.
00318   MBB.erase(I);
00319 }
00320 
00321 void
00322 SPURegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
00323                                      RegScavenger *RS) const
00324 {
00325   unsigned i = 0;
00326   MachineInstr &MI = *II;
00327   MachineBasicBlock &MBB = *MI.getParent();
00328   MachineFunction &MF = *MBB.getParent();
00329   MachineFrameInfo *MFI = MF.getFrameInfo();
00330 
00331   while (!MI.getOperand(i).isFI()) {
00332     ++i;
00333     assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
00334   }
00335 
00336   MachineOperand &SPOp = MI.getOperand(i);
00337   int FrameIndex = SPOp.getIndex();
00338 
00339   // Now add the frame object offset to the offset from r1.
00340   int Offset = MFI->getObjectOffset(FrameIndex);
00341 
00342   // Most instructions, except for generated FrameIndex additions using AIr32
00343   // and ILAr32, have the immediate in operand 1. AIr32 and ILAr32 have the
00344   // immediate in operand 2.
00345   unsigned OpNo = 1;
00346   if (MI.getOpcode() == SPU::AIr32 || MI.getOpcode() == SPU::ILAr32)
00347     OpNo = 2;
00348 
00349   MachineOperand &MO = MI.getOperand(OpNo);
00350 
00351   // Offset is biased by $lr's slot at the bottom.
00352   Offset += MO.getImm() + MFI->getStackSize() + SPUFrameInfo::minStackSize();
00353   assert((Offset & 0xf) == 0
00354          && "16-byte alignment violated in eliminateFrameIndex");
00355 
00356   // Replace the FrameIndex with base register with $sp (aka $r1)
00357   SPOp.ChangeToRegister(SPU::R1, false);
00358   if (Offset > SPUFrameInfo::maxFrameOffset()
00359       || Offset < SPUFrameInfo::minFrameOffset()) {
00360     cerr << "Large stack adjustment ("
00361          << Offset
00362          << ") in SPURegisterInfo::eliminateFrameIndex.";
00363   } else {
00364     MO.ChangeToImmediate(Offset);
00365   }
00366 }
00367 
00368 /// determineFrameLayout - Determine the size of the frame and maximum call
00369 /// frame size.
00370 void
00371 SPURegisterInfo::determineFrameLayout(MachineFunction &MF) const
00372 {
00373   MachineFrameInfo *MFI = MF.getFrameInfo();
00374 
00375   // Get the number of bytes to allocate from the FrameInfo
00376   unsigned FrameSize = MFI->getStackSize();
00377 
00378   // Get the alignments provided by the target, and the maximum alignment
00379   // (if any) of the fixed frame objects.
00380   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
00381   unsigned Align = std::max(TargetAlign, MFI->getMaxAlignment());
00382   assert(isPowerOf2_32(Align) && "Alignment is not power of 2");
00383   unsigned AlignMask = Align - 1;
00384 
00385   // Get the maximum call frame size of all the calls.
00386   unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
00387 
00388   // If we have dynamic alloca then maxCallFrameSize needs to be aligned so
00389   // that allocations will be aligned.
00390   if (MFI->hasVarSizedObjects())
00391     maxCallFrameSize = (maxCallFrameSize + AlignMask) & ~AlignMask;
00392 
00393   // Update maximum call frame size.
00394   MFI->setMaxCallFrameSize(maxCallFrameSize);
00395 
00396   // Include call frame size in total.
00397   FrameSize += maxCallFrameSize;
00398 
00399   // Make sure the frame is aligned.
00400   FrameSize = (FrameSize + AlignMask) & ~AlignMask;
00401 
00402   // Update frame info.
00403   MFI->setStackSize(FrameSize);
00404 }
00405 
00406 void SPURegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
00407                                                            RegScavenger *RS)
00408   const {
00409   // Mark LR and SP unused, since the prolog spills them to stack and
00410   // we don't want anyone else to spill them for us.
00411   //
00412   // Also, unless R2 is really used someday, don't spill it automatically.
00413   MF.getRegInfo().setPhysRegUnused(SPU::R0);
00414   MF.getRegInfo().setPhysRegUnused(SPU::R1);
00415   MF.getRegInfo().setPhysRegUnused(SPU::R2);
00416 }
00417 
00418 void SPURegisterInfo::emitPrologue(MachineFunction &MF) const
00419 {
00420   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
00421   MachineBasicBlock::iterator MBBI = MBB.begin();
00422   MachineFrameInfo *MFI = MF.getFrameInfo();
00423   MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
00424 
00425   // Prepare for debug frame info.
00426   bool hasDebugInfo = MMI && MMI->hasDebugInfo();
00427   unsigned FrameLabelId = 0;
00428 
00429   // Move MBBI back to the beginning of the function.
00430   MBBI = MBB.begin();
00431 
00432   // Work out frame sizes.
00433   determineFrameLayout(MF);
00434   int FrameSize = MFI->getStackSize();
00435 
00436   assert((FrameSize & 0xf) == 0
00437          && "SPURegisterInfo::emitPrologue: FrameSize not aligned");
00438 
00439   if (FrameSize > 0 || MFI->hasCalls()) {
00440     FrameSize = -(FrameSize + SPUFrameInfo::minStackSize());
00441     if (hasDebugInfo) {
00442       // Mark effective beginning of when frame pointer becomes valid.
00443       FrameLabelId = MMI->NextLabelID();
00444       BuildMI(MBB, MBBI, TII.get(SPU::DBG_LABEL)).addImm(FrameLabelId);
00445     }
00446 
00447     // Adjust stack pointer, spilling $lr -> 16($sp) and $sp -> -FrameSize($sp)
00448     // for the ABI
00449     BuildMI(MBB, MBBI, TII.get(SPU::STQDr32), SPU::R0).addImm(16)
00450       .addReg(SPU::R1);
00451     if (isS10Constant(FrameSize)) {
00452       // Spill $sp to adjusted $sp
00453       BuildMI(MBB, MBBI, TII.get(SPU::STQDr32), SPU::R1).addImm(FrameSize)
00454         .addReg(SPU::R1);
00455       // Adjust $sp by required amout
00456       BuildMI(MBB, MBBI, TII.get(SPU::AIr32), SPU::R1).addReg(SPU::R1)
00457         .addImm(FrameSize);
00458     } else if (FrameSize <= (1 << 16) - 1 && FrameSize >= -(1 << 16)) {
00459       // Frame size can be loaded into ILr32n, so temporarily spill $r2 and use
00460       // $r2 to adjust $sp:
00461       BuildMI(MBB, MBBI, TII.get(SPU::STQDr128), SPU::R2)
00462         .addImm(-16)
00463         .addReg(SPU::R1);
00464       BuildMI(MBB, MBBI, TII.get(SPU::ILr32), SPU::R2)
00465         .addImm(FrameSize);
00466       BuildMI(MBB, MBBI, TII.get(SPU::STQDr32), SPU::R1)
00467         .addReg(SPU::R2)
00468         .addReg(SPU::R1);
00469       BuildMI(MBB, MBBI, TII.get(SPU::Ar32), SPU::R1)
00470         .addReg(SPU::R1)
00471         .addReg(SPU::R2);
00472       BuildMI(MBB, MBBI, TII.get(SPU::SFIr32), SPU::R2)
00473         .addReg(SPU::R2)
00474         .addImm(16);
00475       BuildMI(MBB, MBBI, TII.get(SPU::LQXr128), SPU::R2)
00476         .addReg(SPU::R2)
00477         .addReg(SPU::R1);
00478     } else {
00479       cerr << "Unhandled frame size: " << FrameSize << "\n";
00480       abort();
00481     }
00482 
00483     if (hasDebugInfo) {
00484       std::vector<MachineMove> &Moves = MMI->getFrameMoves();
00485 
00486       // Show update of SP.
00487       MachineLocation SPDst(MachineLocation::VirtualFP);
00488       MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize);
00489       Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
00490 
00491       // Add callee saved registers to move list.
00492       const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
00493       for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
00494         int Offset = MFI->getObjectOffset(CSI[I].getFrameIdx());
00495         unsigned Reg = CSI[I].getReg();
00496         if (Reg == SPU::R0) continue;
00497         MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
00498         MachineLocation CSSrc(Reg);
00499         Moves.push_back(MachineMove(FrameLabelId, CSDst, CSSrc));
00500       }
00501 
00502       // Mark effective beginning of when frame pointer is ready.
00503       unsigned ReadyLabelId = MMI->NextLabelID();
00504       BuildMI(MBB, MBBI, TII.get(SPU::DBG_LABEL)).addImm(ReadyLabelId);
00505 
00506       MachineLocation FPDst(SPU::R1);
00507       MachineLocation FPSrc(MachineLocation::VirtualFP);
00508       Moves.push_back(MachineMove(ReadyLabelId, FPDst, FPSrc));
00509     }
00510   } else {
00511     // This is a leaf function -- insert a branch hint iff there are
00512     // sufficient number instructions in the basic block. Note that
00513     // this is just a best guess based on the basic block's size.
00514     if (MBB.size() >= (unsigned) SPUFrameInfo::branchHintPenalty()) {
00515       MachineBasicBlock::iterator MBBI = prior(MBB.end());
00516       // Insert terminator label
00517       unsigned BranchLabelId = MMI->NextLabelID();
00518       BuildMI(MBB, MBBI, TII.get(SPU::DBG_LABEL)).addImm(BranchLabelId);
00519     }
00520   }
00521 }
00522 
00523 void
00524 SPURegisterInfo::emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const
00525 {
00526   MachineBasicBlock::iterator MBBI = prior(MBB.end());
00527   const MachineFrameInfo *MFI = MF.getFrameInfo();
00528   int FrameSize = MFI->getStackSize();
00529   int LinkSlotOffset = SPUFrameInfo::stackSlotSize();
00530 
00531   assert(MBBI->getOpcode() == SPU::RET &&
00532          "Can only insert epilog into returning blocks");
00533   assert((FrameSize & 0xf) == 0
00534          && "SPURegisterInfo::emitEpilogue: FrameSize not aligned");
00535   if (FrameSize > 0 || MFI->hasCalls()) {
00536     FrameSize = FrameSize + SPUFrameInfo::minStackSize();
00537     if (isS10Constant(FrameSize + LinkSlotOffset)) {
00538       // Reload $lr, adjust $sp by required amount
00539       // Note: We do this to slightly improve dual issue -- not by much, but it
00540       // is an opportunity for dual issue.
00541       BuildMI(MBB, MBBI, TII.get(SPU::LQDr128), SPU::R0)
00542         .addImm(FrameSize + LinkSlotOffset)
00543         .addReg(SPU::R1);
00544       BuildMI(MBB, MBBI, TII.get(SPU::AIr32), SPU::R1)
00545         .addReg(SPU::R1)
00546         .addImm(FrameSize);
00547     } else if (FrameSize <= (1 << 16) - 1 && FrameSize >= -(1 << 16)) {
00548       // Frame size can be loaded into ILr32n, so temporarily spill $r2 and use
00549       // $r2 to adjust $sp:
00550       BuildMI(MBB, MBBI, TII.get(SPU::STQDr128), SPU::R2)
00551         .addImm(16)
00552         .addReg(SPU::R1);
00553       BuildMI(MBB, MBBI, TII.get(SPU::ILr32), SPU::R2)
00554         .addImm(FrameSize);
00555       BuildMI(MBB, MBBI, TII.get(SPU::Ar32), SPU::R1)
00556         .addReg(SPU::R1)
00557         .addReg(SPU::R2);
00558       BuildMI(MBB, MBBI, TII.get(SPU::LQDr128), SPU::R0)
00559         .addImm(16)
00560         .addReg(SPU::R2);
00561       BuildMI(MBB, MBBI, TII.get(SPU::SFIr32), SPU::R2).
00562         addReg(SPU::R2)
00563         .addImm(16);
00564       BuildMI(MBB, MBBI, TII.get(SPU::LQXr128), SPU::R2)
00565         .addReg(SPU::R2)
00566         .addReg(SPU::R1);
00567     } else {
00568       cerr << "Unhandled frame size: " << FrameSize << "\n";
00569       abort();
00570     }
00571    }
00572 }
00573 
00574 unsigned
00575 SPURegisterInfo::getRARegister() const
00576 {
00577   return SPU::R0;
00578 }
00579 
00580 unsigned
00581 SPURegisterInfo::getFrameRegister(MachineFunction &MF) const
00582 {
00583   return SPU::R1;
00584 }
00585 
00586 void
00587 SPURegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves) const
00588 {
00589   // Initial state of the frame pointer is R1.
00590   MachineLocation Dst(MachineLocation::VirtualFP);
00591   MachineLocation Src(SPU::R1, 0);
00592   Moves.push_back(MachineMove(0, Dst, Src));
00593 }
00594 
00595 
00596 int
00597 SPURegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
00598   // FIXME: Most probably dwarf numbers differs for Linux and Darwin
00599   return SPUGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
00600 }
00601 
00602 #include "SPUGenRegisterInfo.inc"