lib/CodeGen/SelectionDAG/ScheduleDAGSDNodesEmit.cpp

   1 //===---- ScheduleDAGEmit.cpp - Emit routines for the ScheduleDAG class ---===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This implements the Emit routines for the ScheduleDAG class, which creates
  11 // MachineInstrs according to the computed schedule.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #define DEBUG_TYPE "pre-RA-sched"
  16 #include "ScheduleDAGSDNodes.h"
  17 #include "llvm/CodeGen/MachineConstantPool.h"
  18 #include "llvm/CodeGen/MachineFunction.h"
  19 #include "llvm/CodeGen/MachineInstrBuilder.h"
  20 #include "llvm/CodeGen/MachineRegisterInfo.h"
  21 #include "llvm/Target/TargetData.h"
  22 #include "llvm/Target/TargetMachine.h"
  23 #include "llvm/Target/TargetInstrInfo.h"
  24 #include "llvm/Target/TargetLowering.h"
  25 #include "llvm/ADT/Statistic.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/Debug.h"
  28 #include "llvm/Support/MathExtras.h"
  29 using namespace llvm;
  30
  31 /// getInstrOperandRegClass - Return register class of the operand of an
  32 /// instruction of the specified TargetInstrDesc.
  33 static const TargetRegisterClass*
  34 getInstrOperandRegClass(const TargetRegisterInfo *TRI,
  35                         const TargetInstrDesc &II, unsigned Op) {
  36   if (Op >= II.getNumOperands()) {
  37     assert(II.isVariadic() && "Invalid operand # of instruction");
  38     return NULL;
  39   }
  40   if (II.OpInfo[Op].isLookupPtrRegClass())
  41     return TRI->getPointerRegClass();
  42   return TRI->getRegClass(II.OpInfo[Op].RegClass);
  43 }
  44
  45 /// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
  46 /// implicit physical register output.
  47 void ScheduleDAGSDNodes::EmitCopyFromReg(SDNode *Node, unsigned ResNo,
  48                                          bool IsClone, bool IsCloned,
  49                                          unsigned SrcReg,
  50                                          DenseMap<SDValue, unsigned> &VRBaseMap) {
  51   unsigned VRBase = 0;
  52   if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
  53     // Just use the input register directly!
  54     SDValue Op(Node, ResNo);
  55     if (IsClone)
  56       VRBaseMap.erase(Op);
  57     bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second;
  58     isNew = isNew; // Silence compiler warning.
  59     assert(isNew && "Node emitted out of order - early");
  60     return;
  61   }
  62
  63   // If the node is only used by a CopyToReg and the dest reg is a vreg, use
  64   // the CopyToReg'd destination register instead of creating a new vreg.
  65   bool MatchReg = true;
  66   const TargetRegisterClass *UseRC = NULL;
  67   if (!IsClone && !IsCloned)
  68     for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
  69          UI != E; ++UI) {
  70       SDNode *User = *UI;
  71       bool Match = true;
  72       if (User->getOpcode() == ISD::CopyToReg &&
  73           User->getOperand(2).getNode() == Node &&
  74           User->getOperand(2).getResNo() == ResNo) {
  75         unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
  76         if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
  77           VRBase = DestReg;
  78           Match = false;
  79         } else if (DestReg != SrcReg)
  80           Match = false;
  81       } else {
  82         for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
  83           SDValue Op = User->getOperand(i);
  84           if (Op.getNode() != Node || Op.getResNo() != ResNo)
  85             continue;
  86           MVT VT = Node->getValueType(Op.getResNo());
  87           if (VT == MVT::Other || VT == MVT::Flag)
  88             continue;
  89           Match = false;
  90           if (User->isMachineOpcode()) {
  91             const TargetInstrDesc &II = TII->get(User->getMachineOpcode());
  92             const TargetRegisterClass *RC =
  93               getInstrOperandRegClass(TRI, II, i+II.getNumDefs());
  94             if (!UseRC)
  95               UseRC = RC;
  96             else if (RC) {
  97               if (UseRC->hasSuperClass(RC))
  98                 UseRC = RC;
  99               else
 100                 assert((UseRC == RC || RC->hasSuperClass(UseRC)) &&
 101                        "Multiple uses expecting different register classes!");
 102             }
 103           }
 104         }
 105       }
 106       MatchReg &= Match;
 107       if (VRBase)
 108         break;
 109     }
 110
 111   MVT VT = Node->getValueType(ResNo);
 112   const TargetRegisterClass *SrcRC = 0, *DstRC = 0;
 113   SrcRC = TRI->getPhysicalRegisterRegClass(SrcReg, VT);
 114
 115   // Figure out the register class to create for the destreg.
 116   if (VRBase) {
 117     DstRC = MRI.getRegClass(VRBase);
 118   } else if (UseRC) {
 119     assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!");
 120     DstRC = UseRC;
 121   } else {
 122     DstRC = TLI->getRegClassFor(VT);
 123   }
 124
 125   // If all uses are reading from the src physical register and copying the
 126   // register is either impossible or very expensive, then don't create a copy.
 127   if (MatchReg && SrcRC->getCopyCost() < 0) {
 128     VRBase = SrcReg;
 129   } else {
 130     // Create the reg, emit the copy.
 131     VRBase = MRI.createVirtualRegister(DstRC);
 132     bool Emitted = TII->copyRegToReg(*BB, InsertPos, VRBase, SrcReg,
 133                                      DstRC, SrcRC);
 134
 135     assert(Emitted && "Unable to issue a copy instruction!\n");
 136   }
 137
 138   SDValue Op(Node, ResNo);
 139   if (IsClone)
 140     VRBaseMap.erase(Op);
 141   bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
 142   isNew = isNew; // Silence compiler warning.
 143   assert(isNew && "Node emitted out of order - early");
 144 }
 145
 146 /// getDstOfCopyToRegUse - If the only use of the specified result number of
 147 /// node is a CopyToReg, return its destination register. Return 0 otherwise.
 148 unsigned ScheduleDAGSDNodes::getDstOfOnlyCopyToRegUse(SDNode *Node,
 149                                                       unsigned ResNo) const {
 150   if (!Node->hasOneUse())
 151     return 0;
 152
 153   SDNode *User = *Node->use_begin();
 154   if (User->getOpcode() == ISD::CopyToReg &&
 155       User->getOperand(2).getNode() == Node &&
 156       User->getOperand(2).getResNo() == ResNo) {
 157     unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
 158     if (TargetRegisterInfo::isVirtualRegister(Reg))
 159       return Reg;
 160   }
 161   return 0;
 162 }
 163
 164 void ScheduleDAGSDNodes::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
 165                                        const TargetInstrDesc &II,
 166                                        bool IsClone, bool IsCloned,
 167                                        DenseMap<SDValue, unsigned> &VRBaseMap) {
 168   assert(Node->getMachineOpcode() != TargetInstrInfo::IMPLICIT_DEF &&
 169          "IMPLICIT_DEF should have been handled as a special case elsewhere!");
 170
 171   for (unsigned i = 0; i < II.getNumDefs(); ++i) {
 172     // If the specific node value is only used by a CopyToReg and the dest reg
 173     // is a vreg in the same register class, use the CopyToReg'd destination
 174     // register instead of creating a new vreg.
 175     unsigned VRBase = 0;
 176     const TargetRegisterClass *RC = getInstrOperandRegClass(TRI, II, i);
 177
 178     if (!IsClone && !IsCloned)
 179       for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
 180            UI != E; ++UI) {
 181         SDNode *User = *UI;
 182         if (User->getOpcode() == ISD::CopyToReg &&
 183             User->getOperand(2).getNode() == Node &&
 184             User->getOperand(2).getResNo() == i) {
 185           unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
 186           if (TargetRegisterInfo::isVirtualRegister(Reg)) {
 187             const TargetRegisterClass *RegRC = MRI.getRegClass(Reg);
 188             if (RegRC == RC) {
 189               VRBase = Reg;
 190               MI->addOperand(MachineOperand::CreateReg(Reg, true));
 191               break;
 192             }
 193           }
 194         }
 195       }
 196
 197     // Create the result registers for this node and add the result regs to
 198     // the machine instruction.
 199     if (VRBase == 0) {
 200       assert(RC && "Isn't a register operand!");
 201       VRBase = MRI.createVirtualRegister(RC);
 202       MI->addOperand(MachineOperand::CreateReg(VRBase, true));
 203     }
 204
 205     SDValue Op(Node, i);
 206     if (IsClone)
 207       VRBaseMap.erase(Op);
 208     bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
 209     isNew = isNew; // Silence compiler warning.
 210     assert(isNew && "Node emitted out of order - early");
 211   }
 212 }
 213
 214 /// getVR - Return the virtual register corresponding to the specified result
 215 /// of the specified node.
 216 unsigned ScheduleDAGSDNodes::getVR(SDValue Op,
 217                                    DenseMap<SDValue, unsigned> &VRBaseMap) {
 218   if (Op.isMachineOpcode() &&
 219       Op.getMachineOpcode() == TargetInstrInfo::IMPLICIT_DEF) {
 220     // Add an IMPLICIT_DEF instruction before every use.
 221     unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo());
 222     // IMPLICIT_DEF can produce any type of result so its TargetInstrDesc
 223     // does not include operand register class info.
 224     if (!VReg) {
 225       const TargetRegisterClass *RC = TLI->getRegClassFor(Op.getValueType());
 226       VReg = MRI.createVirtualRegister(RC);
 227     }
 228     BuildMI(BB, Op.getDebugLoc(), TII->get(TargetInstrInfo::IMPLICIT_DEF),VReg);
 229     return VReg;
 230   }
 231
 232   DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op);
 233   assert(I != VRBaseMap.end() && "Node emitted out of order - late");
 234   return I->second;
 235 }
 236
 237
 238 /// AddRegisterOperand - Add the specified register as an operand to the
 239 /// specified machine instr. Insert register copies if the register is
 240 /// not in the required register class.
 241 void
 242 ScheduleDAGSDNodes::AddRegisterOperand(MachineInstr *MI, SDValue Op,
 243                                        unsigned IIOpNum,
 244                                        const TargetInstrDesc *II,
 245                                        DenseMap<SDValue, unsigned> &VRBaseMap) {
 246   assert(Op.getValueType() != MVT::Other &&
 247          Op.getValueType() != MVT::Flag &&
 248          "Chain and flag operands should occur at end of operand list!");
 249   // Get/emit the operand.
 250   unsigned VReg = getVR(Op, VRBaseMap);
 251   assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
 252
 253   const TargetInstrDesc &TID = MI->getDesc();
 254   bool isOptDef = IIOpNum < TID.getNumOperands() &&
 255     TID.OpInfo[IIOpNum].isOptionalDef();
 256
 257   // If the instruction requires a register in a different class, create
 258   // a new virtual register and copy the value into it.
 259   if (II) {
 260     const TargetRegisterClass *SrcRC =
 261       MRI.getRegClass(VReg);
 262     const TargetRegisterClass *DstRC =
 263       getInstrOperandRegClass(TRI, *II, IIOpNum);
 264     assert((DstRC || (TID.isVariadic() && IIOpNum >= TID.getNumOperands())) &&
 265            "Don't have operand info for this instruction!");
 266     if (DstRC && SrcRC != DstRC && !SrcRC->hasSuperClass(DstRC)) {
 267       unsigned NewVReg = MRI.createVirtualRegister(DstRC);
 268       bool Emitted = TII->copyRegToReg(*BB, InsertPos, NewVReg, VReg,
 269                                        DstRC, SrcRC);
 270       assert(Emitted && "Unable to issue a copy instruction!\n");
 271       VReg = NewVReg;
 272     }
 273   }
 274
 275   MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef));
 276 }
 277
 278 /// AddOperand - Add the specified operand to the specified machine instr.  II
 279 /// specifies the instruction information for the node, and IIOpNum is the
 280 /// operand number (in the II) that we are adding. IIOpNum and II are used for
 281 /// assertions only.
 282 void ScheduleDAGSDNodes::AddOperand(MachineInstr *MI, SDValue Op,
 283                                     unsigned IIOpNum,
 284                                     const TargetInstrDesc *II,
 285                                     DenseMap<SDValue, unsigned> &VRBaseMap) {
 286   if (Op.isMachineOpcode()) {
 287     AddRegisterOperand(MI, Op, IIOpNum, II, VRBaseMap);
 288   } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
 289     MI->addOperand(MachineOperand::CreateImm(C->getZExtValue()));
 290   } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
 291     const ConstantFP *CFP = F->getConstantFPValue();
 292     MI->addOperand(MachineOperand::CreateFPImm(CFP));
 293   } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
 294     MI->addOperand(MachineOperand::CreateReg(R->getReg(), false));
 295   } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
 296     MI->addOperand(MachineOperand::CreateGA(TGA->getGlobal(),TGA->getOffset()));
 297   } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) {
 298     MI->addOperand(MachineOperand::CreateMBB(BBNode->getBasicBlock()));
 299   } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) {
 300     MI->addOperand(MachineOperand::CreateFI(FI->getIndex()));
 301   } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) {
 302     MI->addOperand(MachineOperand::CreateJTI(JT->getIndex()));
 303   } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
 304     int Offset = CP->getOffset();
 305     unsigned Align = CP->getAlignment();
 306     const Type *Type = CP->getType();
 307     // MachineConstantPool wants an explicit alignment.
 308     if (Align == 0) {
 309       Align = TM.getTargetData()->getPrefTypeAlignment(Type);
 310       if (Align == 0) {
 311         // Alignment of vector types.  FIXME!
 312         Align = TM.getTargetData()->getTypePaddedSize(Type);
 313       }
 314     }
 315
 316     unsigned Idx;
 317     if (CP->isMachineConstantPoolEntry())
 318       Idx = ConstPool->getConstantPoolIndex(CP->getMachineCPVal(), Align);
 319     else
 320       Idx = ConstPool->getConstantPoolIndex(CP->getConstVal(), Align);
 321     MI->addOperand(MachineOperand::CreateCPI(Idx, Offset));
 322   } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
 323     MI->addOperand(MachineOperand::CreateES(ES->getSymbol()));
 324   } else {
 325     assert(Op.getValueType() != MVT::Other &&
 326            Op.getValueType() != MVT::Flag &&
 327            "Chain and flag operands should occur at end of operand list!");
 328     AddRegisterOperand(MI, Op, IIOpNum, II, VRBaseMap);
 329   }
 330 }
 331
 332 /// getSubRegisterRegClass - Returns the register class of specified register
 333 /// class' "SubIdx"'th sub-register class.
 334 static const TargetRegisterClass*
 335 getSubRegisterRegClass(const TargetRegisterClass *TRC, unsigned SubIdx) {
 336   // Pick the register class of the subregister
 337   TargetRegisterInfo::regclass_iterator I =
 338     TRC->subregclasses_begin() + SubIdx-1;
 339   assert(I < TRC->subregclasses_end() &&
 340          "Invalid subregister index for register class");
 341   return *I;
 342 }
 343
 344 /// getSuperRegisterRegClass - Returns the register class of a superreg A whose
 345 /// "SubIdx"'th sub-register class is the specified register class and whose
 346 /// type matches the specified type.
 347 static const TargetRegisterClass*
 348 getSuperRegisterRegClass(const TargetRegisterClass *TRC,
 349                          unsigned SubIdx, MVT VT) {
 350   // Pick the register class of the superegister for this type
 351   for (TargetRegisterInfo::regclass_iterator I = TRC->superregclasses_begin(),
 352          E = TRC->superregclasses_end(); I != E; ++I)
 353     if ((*I)->hasType(VT) && getSubRegisterRegClass(*I, SubIdx) == TRC)
 354       return *I;
 355   assert(false && "Couldn't find the register class");
 356   return 0;
 357 }
 358
 359 /// EmitSubregNode - Generate machine code for subreg nodes.
 360 ///
 361 void ScheduleDAGSDNodes::EmitSubregNode(SDNode *Node,
 362                                         DenseMap<SDValue, unsigned> &VRBaseMap) {
 363   unsigned VRBase = 0;
 364   unsigned Opc = Node->getMachineOpcode();
 365
 366   // If the node is only used by a CopyToReg and the dest reg is a vreg, use
 367   // the CopyToReg'd destination register instead of creating a new vreg.
 368   for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
 369        UI != E; ++UI) {
 370     SDNode *User = *UI;
 371     if (User->getOpcode() == ISD::CopyToReg &&
 372         User->getOperand(2).getNode() == Node) {
 373       unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
 374       if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
 375         VRBase = DestReg;
 376         break;
 377       }
 378     }
 379   }
 380
 381   if (Opc == TargetInstrInfo::EXTRACT_SUBREG) {
 382     unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
 383
 384     // Create the extract_subreg machine instruction.
 385     MachineInstr *MI = BuildMI(MF, Node->getDebugLoc(),
 386                                TII->get(TargetInstrInfo::EXTRACT_SUBREG));
 387
 388     // Figure out the register class to create for the destreg.
 389     unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
 390     const TargetRegisterClass *TRC = MRI.getRegClass(VReg);
 391     const TargetRegisterClass *SRC = getSubRegisterRegClass(TRC, SubIdx);
 392
 393     // Figure out the register class to create for the destreg.
 394     // Note that if we're going to directly use an existing register,
 395     // it must be precisely the required class, and not a subclass
 396     // thereof.
 397     if (VRBase == 0 || SRC != MRI.getRegClass(VRBase)) {
 398       // Create the reg
 399       assert(SRC && "Couldn't find source register class");
 400       VRBase = MRI.createVirtualRegister(SRC);
 401     }
 402
 403     // Add def, source, and subreg index
 404     MI->addOperand(MachineOperand::CreateReg(VRBase, true));
 405     AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap);
 406     MI->addOperand(MachineOperand::CreateImm(SubIdx));
 407     BB->insert(InsertPos, MI);
 408   } else if (Opc == TargetInstrInfo::INSERT_SUBREG ||
 409              Opc == TargetInstrInfo::SUBREG_TO_REG) {
 410     SDValue N0 = Node->getOperand(0);
 411     SDValue N1 = Node->getOperand(1);
 412     SDValue N2 = Node->getOperand(2);
 413     unsigned SubReg = getVR(N1, VRBaseMap);
 414     unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue();
 415     const TargetRegisterClass *TRC = MRI.getRegClass(SubReg);
 416     const TargetRegisterClass *SRC =
 417       getSuperRegisterRegClass(TRC, SubIdx,
 418                                Node->getValueType(0));
 419
 420     // Figure out the register class to create for the destreg.
 421     // Note that if we're going to directly use an existing register,
 422     // it must be precisely the required class, and not a subclass
 423     // thereof.
 424     if (VRBase == 0 || SRC != MRI.getRegClass(VRBase)) {
 425       // Create the reg
 426       assert(SRC && "Couldn't find source register class");
 427       VRBase = MRI.createVirtualRegister(SRC);
 428     }
 429
 430     // Create the insert_subreg or subreg_to_reg machine instruction.
 431     MachineInstr *MI = BuildMI(MF, Node->getDebugLoc(), TII->get(Opc));
 432     MI->addOperand(MachineOperand::CreateReg(VRBase, true));
 433
 434     // If creating a subreg_to_reg, then the first input operand
 435     // is an implicit value immediate, otherwise it's a register
 436     if (Opc == TargetInstrInfo::SUBREG_TO_REG) {
 437       const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
 438       MI->addOperand(MachineOperand::CreateImm(SD->getZExtValue()));
 439     } else
 440       AddOperand(MI, N0, 0, 0, VRBaseMap);
 441     // Add the subregster being inserted
 442     AddOperand(MI, N1, 0, 0, VRBaseMap);
 443     MI->addOperand(MachineOperand::CreateImm(SubIdx));
 444     BB->insert(InsertPos, MI);
 445   } else
 446     assert(0 && "Node is not insert_subreg, extract_subreg, or subreg_to_reg");
 447
 448   SDValue Op(Node, 0);
 449   bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
 450   isNew = isNew; // Silence compiler warning.
 451   assert(isNew && "Node emitted out of order - early");
 452 }
 453
 454 /// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes.
 455 /// COPY_TO_REGCLASS is just a normal copy, except that the destination
 456 /// register is constrained to be in a particular register class.
 457 ///
 458 void
 459 ScheduleDAGSDNodes::EmitCopyToRegClassNode(SDNode *Node,
 460                                        DenseMap<SDValue, unsigned> &VRBaseMap) {
 461   unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
 462   const TargetRegisterClass *SrcRC = MRI.getRegClass(VReg);
 463
 464   unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
 465   const TargetRegisterClass *DstRC = TRI->getRegClass(DstRCIdx);
 466
 467   // Create the new VReg in the destination class and emit a copy.
 468   unsigned NewVReg = MRI.createVirtualRegister(DstRC);
 469   bool Emitted = TII->copyRegToReg(*BB, InsertPos, NewVReg, VReg,
 470                                    DstRC, SrcRC);
 471   assert(Emitted &&
 472          "Unable to issue a copy instruction for a COPY_TO_REGCLASS node!\n");
 473
 474   SDValue Op(Node, 0);
 475   bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
 476   isNew = isNew; // Silence compiler warning.
 477   assert(isNew && "Node emitted out of order - early");
 478 }
 479
 480 /// EmitNode - Generate machine code for an node and needed dependencies.
 481 ///
 482 void ScheduleDAGSDNodes::EmitNode(SDNode *Node, bool IsClone, bool IsCloned,
 483                                   DenseMap<SDValue, unsigned> &VRBaseMap) {
 484   // If machine instruction
 485   if (Node->isMachineOpcode()) {
 486     unsigned Opc = Node->getMachineOpcode();
 487
 488     // Handle subreg insert/extract specially
 489     if (Opc == TargetInstrInfo::EXTRACT_SUBREG ||
 490         Opc == TargetInstrInfo::INSERT_SUBREG ||
 491         Opc == TargetInstrInfo::SUBREG_TO_REG) {
 492       EmitSubregNode(Node, VRBaseMap);
 493       return;
 494     }
 495
 496     // Handle COPY_TO_REGCLASS specially.
 497     if (Opc == TargetInstrInfo::COPY_TO_REGCLASS) {
 498       EmitCopyToRegClassNode(Node, VRBaseMap);
 499       return;
 500     }
 501
 502     if (Opc == TargetInstrInfo::IMPLICIT_DEF)
 503       // We want a unique VR for each IMPLICIT_DEF use.
 504       return;
 505
 506     const TargetInstrDesc &II = TII->get(Opc);
 507     unsigned NumResults = CountResults(Node);
 508     unsigned NodeOperands = CountOperands(Node);
 509     unsigned MemOperandsEnd = ComputeMemOperandsEnd(Node);
 510     bool HasPhysRegOuts = (NumResults > II.getNumDefs()) &&
 511                           II.getImplicitDefs() != 0;
 512 #ifndef NDEBUG
 513     unsigned NumMIOperands = NodeOperands + NumResults;
 514     assert((II.getNumOperands() == NumMIOperands ||
 515             HasPhysRegOuts || II.isVariadic()) &&
 516            "#operands for dag node doesn't match .td file!");
 517 #endif
 518
 519     // Create the new machine instruction.
 520     MachineInstr *MI = BuildMI(MF, Node->getDebugLoc(), II);
 521
 522     // Add result register values for things that are defined by this
 523     // instruction.
 524     if (NumResults)
 525       CreateVirtualRegisters(Node, MI, II, IsClone, IsCloned, VRBaseMap);
 526
 527     // Emit all of the actual operands of this instruction, adding them to the
 528     // instruction as appropriate.
 529     for (unsigned i = 0; i != NodeOperands; ++i)
 530       AddOperand(MI, Node->getOperand(i), i+II.getNumDefs(), &II, VRBaseMap);
 531
 532     // Emit all of the memory operands of this instruction
 533     for (unsigned i = NodeOperands; i != MemOperandsEnd; ++i)
 534       AddMemOperand(MI, cast<MemOperandSDNode>(Node->getOperand(i))->MO);
 535
 536     if (II.usesCustomDAGSchedInsertionHook()) {
 537       // Insert this instruction into the basic block using a target
 538       // specific inserter which may returns a new basic block.
 539       BB = TLI->EmitInstrWithCustomInserter(MI, BB);
 540       InsertPos = BB->end();
 541     } else {
 542       BB->insert(InsertPos, MI);
 543     }
 544
 545     // Additional results must be an physical register def.
 546     if (HasPhysRegOuts) {
 547       for (unsigned i = II.getNumDefs(); i < NumResults; ++i) {
 548         unsigned Reg = II.getImplicitDefs()[i - II.getNumDefs()];
 549         if (Node->hasAnyUseOfValue(i))
 550           EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap);
 551       }
 552     }
 553     return;
 554   }
 555
 556   switch (Node->getOpcode()) {
 557   default:
 558 #ifndef NDEBUG
 559     Node->dump(DAG);
 560 #endif
 561     assert(0 && "This target-independent node should have been selected!");
 562     break;
 563   case ISD::EntryToken:
 564     assert(0 && "EntryToken should have been excluded from the schedule!");
 565     break;
 566   case ISD::TokenFactor: // fall thru
 567     break;
 568   case ISD::CopyToReg: {
 569     unsigned SrcReg;
 570     SDValue SrcVal = Node->getOperand(2);
 571     if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal))
 572       SrcReg = R->getReg();
 573     else
 574       SrcReg = getVR(SrcVal, VRBaseMap);
 575
 576     unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
 577     if (SrcReg == DestReg) // Coalesced away the copy? Ignore.
 578       break;
 579
 580     const TargetRegisterClass *SrcTRC = 0, *DstTRC = 0;
 581     // Get the register classes of the src/dst.
 582     if (TargetRegisterInfo::isVirtualRegister(SrcReg))
 583       SrcTRC = MRI.getRegClass(SrcReg);
 584     else
 585       SrcTRC = TRI->getPhysicalRegisterRegClass(SrcReg,SrcVal.getValueType());
 586
 587     if (TargetRegisterInfo::isVirtualRegister(DestReg))
 588       DstTRC = MRI.getRegClass(DestReg);
 589     else
 590       DstTRC = TRI->getPhysicalRegisterRegClass(DestReg,
 591                                             Node->getOperand(1).getValueType());
 592
 593     bool Emitted = TII->copyRegToReg(*BB, InsertPos, DestReg, SrcReg,
 594                                      DstTRC, SrcTRC);
 595     assert(Emitted && "Unable to issue a copy instruction!\n");
 596     break;
 597   }
 598   case ISD::CopyFromReg: {
 599     unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
 600     EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap);
 601     break;
 602   }
 603   case ISD::INLINEASM: {
 604     unsigned NumOps = Node->getNumOperands();
 605     if (Node->getOperand(NumOps-1).getValueType() == MVT::Flag)
 606       --NumOps;  // Ignore the flag operand.
 607
 608     // Create the inline asm machine instruction.
 609     MachineInstr *MI = BuildMI(MF, Node->getDebugLoc(),
 610                                TII->get(TargetInstrInfo::INLINEASM));
 611
 612     // Add the asm string as an external symbol operand.
 613     const char *AsmStr =
 614       cast<ExternalSymbolSDNode>(Node->getOperand(1))->getSymbol();
 615     MI->addOperand(MachineOperand::CreateES(AsmStr));
 616
 617     // Add all of the operand registers to the instruction.
 618     for (unsigned i = 2; i != NumOps;) {
 619       unsigned Flags =
 620         cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
 621       unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
 622
 623       MI->addOperand(MachineOperand::CreateImm(Flags));
 624       ++i;  // Skip the ID value.
 625
 626       switch (Flags & 7) {
 627       default: assert(0 && "Bad flags!");
 628       case 2:   // Def of register.
 629         for (; NumVals; --NumVals, ++i) {
 630           unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
 631           MI->addOperand(MachineOperand::CreateReg(Reg, true));
 632         }
 633         break;
 634       case 6:   // Def of earlyclobber register.
 635         for (; NumVals; --NumVals, ++i) {
 636           unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
 637           MI->addOperand(MachineOperand::CreateReg(Reg, true, false, false,
 638                                                    false, 0, true));
 639         }
 640         break;
 641       case 1:  // Use of register.
 642       case 3:  // Immediate.
 643       case 4:  // Addressing mode.
 644         // The addressing mode has been selected, just add all of the
 645         // operands to the machine instruction.
 646         for (; NumVals; --NumVals, ++i)
 647           AddOperand(MI, Node->getOperand(i), 0, 0, VRBaseMap);
 648         break;
 649       }
 650     }
 651     BB->insert(InsertPos, MI);
 652     break;
 653   }
 654   }
 655 }
 656
 657 /// EmitSchedule - Emit the machine code in scheduled order.
 658 MachineBasicBlock *ScheduleDAGSDNodes::EmitSchedule() {
 659   DenseMap<SDValue, unsigned> VRBaseMap;
 660   DenseMap<SUnit*, unsigned> CopyVRBaseMap;
 661   for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
 662     SUnit *SU = Sequence[i];
 663     if (!SU) {
 664       // Null SUnit* is a noop.
 665       EmitNoop();
 666       continue;
 667     }
 668
 669     // For pre-regalloc scheduling, create instructions corresponding to the
 670     // SDNode and any flagged SDNodes and append them to the block.
 671     if (!SU->getNode()) {
 672       // Emit a copy.
 673       EmitPhysRegCopy(SU, CopyVRBaseMap);
 674       continue;
 675     }
 676
 677     SmallVector<SDNode *, 4> FlaggedNodes;
 678     for (SDNode *N = SU->getNode()->getFlaggedNode(); N;
 679          N = N->getFlaggedNode())
 680       FlaggedNodes.push_back(N);
 681     while (!FlaggedNodes.empty()) {
 682       EmitNode(FlaggedNodes.back(), SU->OrigNode != SU, SU->isCloned,VRBaseMap);
 683       FlaggedNodes.pop_back();
 684     }
 685     EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned, VRBaseMap);
 686   }
 687
 688   return BB;
 689 }