InstrEmitter.cpp revision c040719a153df8202f10054f33c9ac581b1c6c57
1//==--- InstrEmitter.cpp - Emit MachineInstrs for the SelectionDAG 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 SelectionDAG class, which creates 11// MachineInstrs based on the decisions of the SelectionDAG instruction 12// selection. 13// 14//===----------------------------------------------------------------------===// 15 16#define DEBUG_TYPE "instr-emitter" 17#include "InstrEmitter.h" 18#include "SDNodeDbgValue.h" 19#include "llvm/CodeGen/MachineConstantPool.h" 20#include "llvm/CodeGen/MachineFunction.h" 21#include "llvm/CodeGen/MachineInstrBuilder.h" 22#include "llvm/CodeGen/MachineRegisterInfo.h" 23#include "llvm/Target/TargetData.h" 24#include "llvm/Target/TargetMachine.h" 25#include "llvm/Target/TargetInstrInfo.h" 26#include "llvm/Target/TargetLowering.h" 27#include "llvm/ADT/Statistic.h" 28#include "llvm/Support/Debug.h" 29#include "llvm/Support/ErrorHandling.h" 30#include "llvm/Support/MathExtras.h" 31using namespace llvm; 32 33/// CountResults - The results of target nodes have register or immediate 34/// operands first, then an optional chain, and optional flag operands (which do 35/// not go into the resulting MachineInstr). 36unsigned InstrEmitter::CountResults(SDNode *Node) { 37 unsigned N = Node->getNumValues(); 38 while (N && Node->getValueType(N - 1) == MVT::Flag) 39 --N; 40 if (N && Node->getValueType(N - 1) == MVT::Other) 41 --N; // Skip over chain result. 42 return N; 43} 44 45/// CountOperands - The inputs to target nodes have any actual inputs first, 46/// followed by an optional chain operand, then an optional flag operand. 47/// Compute the number of actual operands that will go into the resulting 48/// MachineInstr. 49unsigned InstrEmitter::CountOperands(SDNode *Node) { 50 unsigned N = Node->getNumOperands(); 51 while (N && Node->getOperand(N - 1).getValueType() == MVT::Flag) 52 --N; 53 if (N && Node->getOperand(N - 1).getValueType() == MVT::Other) 54 --N; // Ignore chain if it exists. 55 return N; 56} 57 58/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an 59/// implicit physical register output. 60void InstrEmitter:: 61EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, 62 unsigned SrcReg, DenseMap<SDValue, unsigned> &VRBaseMap) { 63 unsigned VRBase = 0; 64 if (TargetRegisterInfo::isVirtualRegister(SrcReg)) { 65 // Just use the input register directly! 66 SDValue Op(Node, ResNo); 67 if (IsClone) 68 VRBaseMap.erase(Op); 69 bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second; 70 isNew = isNew; // Silence compiler warning. 71 assert(isNew && "Node emitted out of order - early"); 72 return; 73 } 74 75 // If the node is only used by a CopyToReg and the dest reg is a vreg, use 76 // the CopyToReg'd destination register instead of creating a new vreg. 77 bool MatchReg = true; 78 const TargetRegisterClass *UseRC = NULL; 79 if (!IsClone && !IsCloned) 80 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 81 UI != E; ++UI) { 82 SDNode *User = *UI; 83 bool Match = true; 84 if (User->getOpcode() == ISD::CopyToReg && 85 User->getOperand(2).getNode() == Node && 86 User->getOperand(2).getResNo() == ResNo) { 87 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 88 if (TargetRegisterInfo::isVirtualRegister(DestReg)) { 89 VRBase = DestReg; 90 Match = false; 91 } else if (DestReg != SrcReg) 92 Match = false; 93 } else { 94 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { 95 SDValue Op = User->getOperand(i); 96 if (Op.getNode() != Node || Op.getResNo() != ResNo) 97 continue; 98 EVT VT = Node->getValueType(Op.getResNo()); 99 if (VT == MVT::Other || VT == MVT::Flag) 100 continue; 101 Match = false; 102 if (User->isMachineOpcode()) { 103 const TargetInstrDesc &II = TII->get(User->getMachineOpcode()); 104 const TargetRegisterClass *RC = 0; 105 if (i+II.getNumDefs() < II.getNumOperands()) 106 RC = II.OpInfo[i+II.getNumDefs()].getRegClass(TRI); 107 if (!UseRC) 108 UseRC = RC; 109 else if (RC) { 110 const TargetRegisterClass *ComRC = getCommonSubClass(UseRC, RC); 111 // If multiple uses expect disjoint register classes, we emit 112 // copies in AddRegisterOperand. 113 if (ComRC) 114 UseRC = ComRC; 115 } 116 } 117 } 118 } 119 MatchReg &= Match; 120 if (VRBase) 121 break; 122 } 123 124 EVT VT = Node->getValueType(ResNo); 125 const TargetRegisterClass *SrcRC = 0, *DstRC = 0; 126 SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT); 127 128 // Figure out the register class to create for the destreg. 129 if (VRBase) { 130 DstRC = MRI->getRegClass(VRBase); 131 } else if (UseRC) { 132 assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!"); 133 DstRC = UseRC; 134 } else { 135 DstRC = TLI->getRegClassFor(VT); 136 } 137 138 // If all uses are reading from the src physical register and copying the 139 // register is either impossible or very expensive, then don't create a copy. 140 if (MatchReg && SrcRC->getCopyCost() < 0) { 141 VRBase = SrcReg; 142 } else { 143 // Create the reg, emit the copy. 144 VRBase = MRI->createVirtualRegister(DstRC); 145 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 146 VRBase).addReg(SrcReg); 147 } 148 149 SDValue Op(Node, ResNo); 150 if (IsClone) 151 VRBaseMap.erase(Op); 152 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 153 isNew = isNew; // Silence compiler warning. 154 assert(isNew && "Node emitted out of order - early"); 155} 156 157/// getDstOfCopyToRegUse - If the only use of the specified result number of 158/// node is a CopyToReg, return its destination register. Return 0 otherwise. 159unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node, 160 unsigned ResNo) const { 161 if (!Node->hasOneUse()) 162 return 0; 163 164 SDNode *User = *Node->use_begin(); 165 if (User->getOpcode() == ISD::CopyToReg && 166 User->getOperand(2).getNode() == Node && 167 User->getOperand(2).getResNo() == ResNo) { 168 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 169 if (TargetRegisterInfo::isVirtualRegister(Reg)) 170 return Reg; 171 } 172 return 0; 173} 174 175void InstrEmitter::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI, 176 const TargetInstrDesc &II, 177 bool IsClone, bool IsCloned, 178 DenseMap<SDValue, unsigned> &VRBaseMap) { 179 assert(Node->getMachineOpcode() != TargetOpcode::IMPLICIT_DEF && 180 "IMPLICIT_DEF should have been handled as a special case elsewhere!"); 181 182 for (unsigned i = 0; i < II.getNumDefs(); ++i) { 183 // If the specific node value is only used by a CopyToReg and the dest reg 184 // is a vreg in the same register class, use the CopyToReg'd destination 185 // register instead of creating a new vreg. 186 unsigned VRBase = 0; 187 const TargetRegisterClass *RC = II.OpInfo[i].getRegClass(TRI); 188 if (II.OpInfo[i].isOptionalDef()) { 189 // Optional def must be a physical register. 190 unsigned NumResults = CountResults(Node); 191 VRBase = cast<RegisterSDNode>(Node->getOperand(i-NumResults))->getReg(); 192 assert(TargetRegisterInfo::isPhysicalRegister(VRBase)); 193 MI->addOperand(MachineOperand::CreateReg(VRBase, true)); 194 } 195 196 if (!VRBase && !IsClone && !IsCloned) 197 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 198 UI != E; ++UI) { 199 SDNode *User = *UI; 200 if (User->getOpcode() == ISD::CopyToReg && 201 User->getOperand(2).getNode() == Node && 202 User->getOperand(2).getResNo() == i) { 203 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 204 if (TargetRegisterInfo::isVirtualRegister(Reg)) { 205 const TargetRegisterClass *RegRC = MRI->getRegClass(Reg); 206 if (RegRC == RC) { 207 VRBase = Reg; 208 MI->addOperand(MachineOperand::CreateReg(Reg, true)); 209 break; 210 } 211 } 212 } 213 } 214 215 // Create the result registers for this node and add the result regs to 216 // the machine instruction. 217 if (VRBase == 0) { 218 assert(RC && "Isn't a register operand!"); 219 VRBase = MRI->createVirtualRegister(RC); 220 MI->addOperand(MachineOperand::CreateReg(VRBase, true)); 221 } 222 223 SDValue Op(Node, i); 224 if (IsClone) 225 VRBaseMap.erase(Op); 226 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 227 isNew = isNew; // Silence compiler warning. 228 assert(isNew && "Node emitted out of order - early"); 229 } 230} 231 232/// getVR - Return the virtual register corresponding to the specified result 233/// of the specified node. 234unsigned InstrEmitter::getVR(SDValue Op, 235 DenseMap<SDValue, unsigned> &VRBaseMap) { 236 if (Op.isMachineOpcode() && 237 Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) { 238 // Add an IMPLICIT_DEF instruction before every use. 239 unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo()); 240 // IMPLICIT_DEF can produce any type of result so its TargetInstrDesc 241 // does not include operand register class info. 242 if (!VReg) { 243 const TargetRegisterClass *RC = TLI->getRegClassFor(Op.getValueType()); 244 VReg = MRI->createVirtualRegister(RC); 245 } 246 BuildMI(*MBB, InsertPos, Op.getDebugLoc(), 247 TII->get(TargetOpcode::IMPLICIT_DEF), VReg); 248 return VReg; 249 } 250 251 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); 252 assert(I != VRBaseMap.end() && "Node emitted out of order - late"); 253 return I->second; 254} 255 256 257/// AddRegisterOperand - Add the specified register as an operand to the 258/// specified machine instr. Insert register copies if the register is 259/// not in the required register class. 260void 261InstrEmitter::AddRegisterOperand(MachineInstr *MI, SDValue Op, 262 unsigned IIOpNum, 263 const TargetInstrDesc *II, 264 DenseMap<SDValue, unsigned> &VRBaseMap, 265 bool IsDebug, bool IsClone, bool IsCloned) { 266 assert(Op.getValueType() != MVT::Other && 267 Op.getValueType() != MVT::Flag && 268 "Chain and flag operands should occur at end of operand list!"); 269 // Get/emit the operand. 270 unsigned VReg = getVR(Op, VRBaseMap); 271 assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?"); 272 273 const TargetInstrDesc &TID = MI->getDesc(); 274 bool isOptDef = IIOpNum < TID.getNumOperands() && 275 TID.OpInfo[IIOpNum].isOptionalDef(); 276 277 // If the instruction requires a register in a different class, create 278 // a new virtual register and copy the value into it. 279 if (II) { 280 const TargetRegisterClass *SrcRC = MRI->getRegClass(VReg); 281 const TargetRegisterClass *DstRC = 0; 282 if (IIOpNum < II->getNumOperands()) 283 DstRC = II->OpInfo[IIOpNum].getRegClass(TRI); 284 assert((DstRC || (TID.isVariadic() && IIOpNum >= TID.getNumOperands())) && 285 "Don't have operand info for this instruction!"); 286 if (DstRC && SrcRC != DstRC && !SrcRC->hasSuperClass(DstRC)) { 287 unsigned NewVReg = MRI->createVirtualRegister(DstRC); 288 BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(), 289 TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg); 290 VReg = NewVReg; 291 } 292 } 293 294 // If this value has only one use, that use is a kill. This is a 295 // conservative approximation. InstrEmitter does trivial coalescing 296 // with CopyFromReg nodes, so don't emit kill flags for them. 297 // Avoid kill flags on Schedule cloned nodes, since there will be 298 // multiple uses. 299 // Tied operands are never killed, so we need to check that. And that 300 // means we need to determine the index of the operand. 301 bool isKill = Op.hasOneUse() && 302 Op.getNode()->getOpcode() != ISD::CopyFromReg && 303 !IsDebug && 304 !(IsClone || IsCloned); 305 if (isKill) { 306 unsigned Idx = MI->getNumOperands(); 307 while (Idx > 0 && 308 MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit()) 309 --Idx; 310 bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1; 311 if (isTied) 312 isKill = false; 313 } 314 315 MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef, 316 false/*isImp*/, isKill, 317 false/*isDead*/, false/*isUndef*/, 318 false/*isEarlyClobber*/, 319 0/*SubReg*/, IsDebug)); 320} 321 322/// AddOperand - Add the specified operand to the specified machine instr. II 323/// specifies the instruction information for the node, and IIOpNum is the 324/// operand number (in the II) that we are adding. IIOpNum and II are used for 325/// assertions only. 326void InstrEmitter::AddOperand(MachineInstr *MI, SDValue Op, 327 unsigned IIOpNum, 328 const TargetInstrDesc *II, 329 DenseMap<SDValue, unsigned> &VRBaseMap, 330 bool IsDebug, bool IsClone, bool IsCloned) { 331 if (Op.isMachineOpcode()) { 332 AddRegisterOperand(MI, Op, IIOpNum, II, VRBaseMap, 333 IsDebug, IsClone, IsCloned); 334 } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) { 335 MI->addOperand(MachineOperand::CreateImm(C->getSExtValue())); 336 } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) { 337 const ConstantFP *CFP = F->getConstantFPValue(); 338 MI->addOperand(MachineOperand::CreateFPImm(CFP)); 339 } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) { 340 MI->addOperand(MachineOperand::CreateReg(R->getReg(), false)); 341 } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) { 342 MI->addOperand(MachineOperand::CreateGA(TGA->getGlobal(), TGA->getOffset(), 343 TGA->getTargetFlags())); 344 } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) { 345 MI->addOperand(MachineOperand::CreateMBB(BBNode->getBasicBlock())); 346 } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) { 347 MI->addOperand(MachineOperand::CreateFI(FI->getIndex())); 348 } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) { 349 MI->addOperand(MachineOperand::CreateJTI(JT->getIndex(), 350 JT->getTargetFlags())); 351 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) { 352 int Offset = CP->getOffset(); 353 unsigned Align = CP->getAlignment(); 354 const Type *Type = CP->getType(); 355 // MachineConstantPool wants an explicit alignment. 356 if (Align == 0) { 357 Align = TM->getTargetData()->getPrefTypeAlignment(Type); 358 if (Align == 0) { 359 // Alignment of vector types. FIXME! 360 Align = TM->getTargetData()->getTypeAllocSize(Type); 361 } 362 } 363 364 unsigned Idx; 365 MachineConstantPool *MCP = MF->getConstantPool(); 366 if (CP->isMachineConstantPoolEntry()) 367 Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align); 368 else 369 Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align); 370 MI->addOperand(MachineOperand::CreateCPI(Idx, Offset, 371 CP->getTargetFlags())); 372 } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) { 373 MI->addOperand(MachineOperand::CreateES(ES->getSymbol(), 374 ES->getTargetFlags())); 375 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) { 376 MI->addOperand(MachineOperand::CreateBA(BA->getBlockAddress(), 377 BA->getTargetFlags())); 378 } else { 379 assert(Op.getValueType() != MVT::Other && 380 Op.getValueType() != MVT::Flag && 381 "Chain and flag operands should occur at end of operand list!"); 382 AddRegisterOperand(MI, Op, IIOpNum, II, VRBaseMap, 383 IsDebug, IsClone, IsCloned); 384 } 385} 386 387/// getSuperRegisterRegClass - Returns the register class of a superreg A whose 388/// "SubIdx"'th sub-register class is the specified register class and whose 389/// type matches the specified type. 390static const TargetRegisterClass* 391getSuperRegisterRegClass(const TargetRegisterClass *TRC, 392 unsigned SubIdx, EVT VT) { 393 // Pick the register class of the superegister for this type 394 for (TargetRegisterInfo::regclass_iterator I = TRC->superregclasses_begin(), 395 E = TRC->superregclasses_end(); I != E; ++I) 396 if ((*I)->hasType(VT) && (*I)->getSubRegisterRegClass(SubIdx) == TRC) 397 return *I; 398 assert(false && "Couldn't find the register class"); 399 return 0; 400} 401 402/// EmitSubregNode - Generate machine code for subreg nodes. 403/// 404void InstrEmitter::EmitSubregNode(SDNode *Node, 405 DenseMap<SDValue, unsigned> &VRBaseMap, 406 bool IsClone, bool IsCloned) { 407 unsigned VRBase = 0; 408 unsigned Opc = Node->getMachineOpcode(); 409 410 // If the node is only used by a CopyToReg and the dest reg is a vreg, use 411 // the CopyToReg'd destination register instead of creating a new vreg. 412 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 413 UI != E; ++UI) { 414 SDNode *User = *UI; 415 if (User->getOpcode() == ISD::CopyToReg && 416 User->getOperand(2).getNode() == Node) { 417 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 418 if (TargetRegisterInfo::isVirtualRegister(DestReg)) { 419 VRBase = DestReg; 420 break; 421 } 422 } 423 } 424 425 if (Opc == TargetOpcode::EXTRACT_SUBREG) { 426 // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub 427 unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); 428 429 // Figure out the register class to create for the destreg. 430 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); 431 const TargetRegisterClass *TRC = MRI->getRegClass(VReg); 432 const TargetRegisterClass *SRC = TRC->getSubRegisterRegClass(SubIdx); 433 assert(SRC && "Invalid subregister index in EXTRACT_SUBREG"); 434 435 // Figure out the register class to create for the destreg. 436 // Note that if we're going to directly use an existing register, 437 // it must be precisely the required class, and not a subclass 438 // thereof. 439 if (VRBase == 0 || SRC != MRI->getRegClass(VRBase)) { 440 // Create the reg 441 assert(SRC && "Couldn't find source register class"); 442 VRBase = MRI->createVirtualRegister(SRC); 443 } 444 445 // Create the extract_subreg machine instruction. 446 MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), 447 TII->get(TargetOpcode::COPY), VRBase); 448 449 // Add source, and subreg index 450 AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap, /*IsDebug=*/false, 451 IsClone, IsCloned); 452 assert(TargetRegisterInfo::isVirtualRegister(MI->getOperand(1).getReg()) && 453 "Cannot yet extract from physregs"); 454 MI->getOperand(1).setSubReg(SubIdx); 455 MBB->insert(InsertPos, MI); 456 } else if (Opc == TargetOpcode::INSERT_SUBREG || 457 Opc == TargetOpcode::SUBREG_TO_REG) { 458 SDValue N0 = Node->getOperand(0); 459 SDValue N1 = Node->getOperand(1); 460 SDValue N2 = Node->getOperand(2); 461 unsigned SubReg = getVR(N1, VRBaseMap); 462 unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue(); 463 const TargetRegisterClass *TRC = MRI->getRegClass(SubReg); 464 const TargetRegisterClass *SRC = 465 getSuperRegisterRegClass(TRC, SubIdx, Node->getValueType(0)); 466 467 // Figure out the register class to create for the destreg. 468 // Note that if we're going to directly use an existing register, 469 // it must be precisely the required class, and not a subclass 470 // thereof. 471 if (VRBase == 0 || SRC != MRI->getRegClass(VRBase)) { 472 // Create the reg 473 assert(SRC && "Couldn't find source register class"); 474 VRBase = MRI->createVirtualRegister(SRC); 475 } 476 477 // Create the insert_subreg or subreg_to_reg machine instruction. 478 MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc)); 479 MI->addOperand(MachineOperand::CreateReg(VRBase, true)); 480 481 // If creating a subreg_to_reg, then the first input operand 482 // is an implicit value immediate, otherwise it's a register 483 if (Opc == TargetOpcode::SUBREG_TO_REG) { 484 const ConstantSDNode *SD = cast<ConstantSDNode>(N0); 485 MI->addOperand(MachineOperand::CreateImm(SD->getZExtValue())); 486 } else 487 AddOperand(MI, N0, 0, 0, VRBaseMap, /*IsDebug=*/false, 488 IsClone, IsCloned); 489 // Add the subregster being inserted 490 AddOperand(MI, N1, 0, 0, VRBaseMap, /*IsDebug=*/false, 491 IsClone, IsCloned); 492 MI->addOperand(MachineOperand::CreateImm(SubIdx)); 493 MBB->insert(InsertPos, MI); 494 } else 495 llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg"); 496 497 SDValue Op(Node, 0); 498 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 499 isNew = isNew; // Silence compiler warning. 500 assert(isNew && "Node emitted out of order - early"); 501} 502 503/// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes. 504/// COPY_TO_REGCLASS is just a normal copy, except that the destination 505/// register is constrained to be in a particular register class. 506/// 507void 508InstrEmitter::EmitCopyToRegClassNode(SDNode *Node, 509 DenseMap<SDValue, unsigned> &VRBaseMap) { 510 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); 511 512 // Create the new VReg in the destination class and emit a copy. 513 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); 514 const TargetRegisterClass *DstRC = TRI->getRegClass(DstRCIdx); 515 unsigned NewVReg = MRI->createVirtualRegister(DstRC); 516 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 517 NewVReg).addReg(VReg); 518 519 SDValue Op(Node, 0); 520 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; 521 isNew = isNew; // Silence compiler warning. 522 assert(isNew && "Node emitted out of order - early"); 523} 524 525/// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes. 526/// 527void InstrEmitter::EmitRegSequence(SDNode *Node, 528 DenseMap<SDValue, unsigned> &VRBaseMap, 529 bool IsClone, bool IsCloned) { 530 const TargetRegisterClass *RC = TLI->getRegClassFor(Node->getValueType(0)); 531 unsigned NewVReg = MRI->createVirtualRegister(RC); 532 MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), 533 TII->get(TargetOpcode::REG_SEQUENCE), NewVReg); 534 unsigned NumOps = Node->getNumOperands(); 535 assert((NumOps & 1) == 0 && 536 "REG_SEQUENCE must have an even number of operands!"); 537 const TargetInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE); 538 for (unsigned i = 0; i != NumOps; ++i) { 539 SDValue Op = Node->getOperand(i); 540 if (i & 1) { 541 unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue(); 542 unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap); 543 const TargetRegisterClass *TRC = MRI->getRegClass(SubReg); 544 const TargetRegisterClass *SRC = 545 TRI->getMatchingSuperRegClass(RC, TRC, SubIdx); 546 if (!SRC) 547 llvm_unreachable("Invalid subregister index in REG_SEQUENCE"); 548 if (SRC != RC) { 549 MRI->setRegClass(NewVReg, SRC); 550 RC = SRC; 551 } 552 } 553 AddOperand(MI, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false, 554 IsClone, IsCloned); 555 } 556 557 MBB->insert(InsertPos, MI); 558 SDValue Op(Node, 0); 559 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; 560 isNew = isNew; // Silence compiler warning. 561 assert(isNew && "Node emitted out of order - early"); 562} 563 564/// EmitDbgValue - Generate machine instruction for a dbg_value node. 565/// 566MachineInstr * 567InstrEmitter::EmitDbgValue(SDDbgValue *SD, 568 DenseMap<SDValue, unsigned> &VRBaseMap) { 569 uint64_t Offset = SD->getOffset(); 570 MDNode* MDPtr = SD->getMDPtr(); 571 DebugLoc DL = SD->getDebugLoc(); 572 573 if (SD->getKind() == SDDbgValue::FRAMEIX) { 574 // Stack address; this needs to be lowered in target-dependent fashion. 575 // EmitTargetCodeForFrameDebugValue is responsible for allocation. 576 unsigned FrameIx = SD->getFrameIx(); 577 return TII->emitFrameIndexDebugValue(*MF, FrameIx, Offset, MDPtr, DL); 578 } 579 // Otherwise, we're going to create an instruction here. 580 const TargetInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE); 581 MachineInstrBuilder MIB = BuildMI(*MF, DL, II); 582 if (SD->getKind() == SDDbgValue::SDNODE) { 583 SDNode *Node = SD->getSDNode(); 584 SDValue Op = SDValue(Node, SD->getResNo()); 585 // It's possible we replaced this SDNode with other(s) and therefore 586 // didn't generate code for it. It's better to catch these cases where 587 // they happen and transfer the debug info, but trying to guarantee that 588 // in all cases would be very fragile; this is a safeguard for any 589 // that were missed. 590 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); 591 if (I==VRBaseMap.end()) 592 MIB.addReg(0U); // undef 593 else 594 AddOperand(&*MIB, Op, (*MIB).getNumOperands(), &II, VRBaseMap, 595 /*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false); 596 } else if (SD->getKind() == SDDbgValue::CONST) { 597 const Value *V = SD->getConst(); 598 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 599 // FIXME: SDDbgValue constants aren't updated with legalization, so it's 600 // possible to have i128 constants in them at this point. Dwarf writer 601 // does not handle i128 constants at the moment so, as a crude workaround, 602 // just drop the debug info if this happens. 603 if (!CI->getValue().isSignedIntN(64)) 604 MIB.addReg(0U); 605 else 606 MIB.addImm(CI->getSExtValue()); 607 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) { 608 MIB.addFPImm(CF); 609 } else { 610 // Could be an Undef. In any case insert an Undef so we can see what we 611 // dropped. 612 MIB.addReg(0U); 613 } 614 } else { 615 // Insert an Undef so we can see what we dropped. 616 MIB.addReg(0U); 617 } 618 619 MIB.addImm(Offset).addMetadata(MDPtr); 620 return &*MIB; 621} 622 623/// EmitMachineNode - Generate machine code for a target-specific node and 624/// needed dependencies. 625/// 626void InstrEmitter:: 627EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, 628 DenseMap<SDValue, unsigned> &VRBaseMap) { 629 unsigned Opc = Node->getMachineOpcode(); 630 631 // Handle subreg insert/extract specially 632 if (Opc == TargetOpcode::EXTRACT_SUBREG || 633 Opc == TargetOpcode::INSERT_SUBREG || 634 Opc == TargetOpcode::SUBREG_TO_REG) { 635 EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned); 636 return; 637 } 638 639 // Handle COPY_TO_REGCLASS specially. 640 if (Opc == TargetOpcode::COPY_TO_REGCLASS) { 641 EmitCopyToRegClassNode(Node, VRBaseMap); 642 return; 643 } 644 645 // Handle REG_SEQUENCE specially. 646 if (Opc == TargetOpcode::REG_SEQUENCE) { 647 EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned); 648 return; 649 } 650 651 if (Opc == TargetOpcode::IMPLICIT_DEF) 652 // We want a unique VR for each IMPLICIT_DEF use. 653 return; 654 655 const TargetInstrDesc &II = TII->get(Opc); 656 unsigned NumResults = CountResults(Node); 657 unsigned NodeOperands = CountOperands(Node); 658 bool HasPhysRegOuts = NumResults > II.getNumDefs() && II.getImplicitDefs()!=0; 659#ifndef NDEBUG 660 unsigned NumMIOperands = NodeOperands + NumResults; 661 if (II.isVariadic()) 662 assert(NumMIOperands >= II.getNumOperands() && 663 "Too few operands for a variadic node!"); 664 else 665 assert(NumMIOperands >= II.getNumOperands() && 666 NumMIOperands <= II.getNumOperands()+II.getNumImplicitDefs() && 667 "#operands for dag node doesn't match .td file!"); 668#endif 669 670 // Create the new machine instruction. 671 MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), II); 672 673 // The MachineInstr constructor adds implicit-def operands. Scan through 674 // these to determine which are dead. 675 if (MI->getNumOperands() != 0 && 676 Node->getValueType(Node->getNumValues()-1) == MVT::Flag) { 677 // First, collect all used registers. 678 SmallVector<unsigned, 8> UsedRegs; 679 for (SDNode *F = Node->getFlaggedUser(); F; F = F->getFlaggedUser()) 680 if (F->getOpcode() == ISD::CopyFromReg) 681 UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg()); 682 else { 683 // Collect declared implicit uses. 684 const TargetInstrDesc &TID = TII->get(F->getMachineOpcode()); 685 UsedRegs.append(TID.getImplicitUses(), 686 TID.getImplicitUses() + TID.getNumImplicitUses()); 687 // In addition to declared implicit uses, we must also check for 688 // direct RegisterSDNode operands. 689 for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i) 690 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) { 691 unsigned Reg = R->getReg(); 692 if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg)) 693 UsedRegs.push_back(Reg); 694 } 695 } 696 // Then mark unused registers as dead. 697 MI->setPhysRegsDeadExcept(UsedRegs, *TRI); 698 } 699 700 // Add result register values for things that are defined by this 701 // instruction. 702 if (NumResults) 703 CreateVirtualRegisters(Node, MI, II, IsClone, IsCloned, VRBaseMap); 704 705 // Emit all of the actual operands of this instruction, adding them to the 706 // instruction as appropriate. 707 bool HasOptPRefs = II.getNumDefs() > NumResults; 708 assert((!HasOptPRefs || !HasPhysRegOuts) && 709 "Unable to cope with optional defs and phys regs defs!"); 710 unsigned NumSkip = HasOptPRefs ? II.getNumDefs() - NumResults : 0; 711 for (unsigned i = NumSkip; i != NodeOperands; ++i) 712 AddOperand(MI, Node->getOperand(i), i-NumSkip+II.getNumDefs(), &II, 713 VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned); 714 715 // Transfer all of the memory reference descriptions of this instruction. 716 MI->setMemRefs(cast<MachineSDNode>(Node)->memoperands_begin(), 717 cast<MachineSDNode>(Node)->memoperands_end()); 718 719 // Insert the instruction into position in the block. This needs to 720 // happen before any custom inserter hook is called so that the 721 // hook knows where in the block to insert the replacement code. 722 MBB->insert(InsertPos, MI); 723 724 if (II.usesCustomInsertionHook()) { 725 // Insert this instruction into the basic block using a target 726 // specific inserter which may returns a new basic block. 727 bool AtEnd = InsertPos == MBB->end(); 728 MachineBasicBlock *NewMBB = TLI->EmitInstrWithCustomInserter(MI, MBB); 729 if (NewMBB != MBB) { 730 if (AtEnd) 731 InsertPos = NewMBB->end(); 732 MBB = NewMBB; 733 } 734 return; 735 } 736 737 // Additional results must be an physical register def. 738 if (HasPhysRegOuts) { 739 for (unsigned i = II.getNumDefs(); i < NumResults; ++i) { 740 unsigned Reg = II.getImplicitDefs()[i - II.getNumDefs()]; 741 if (Node->hasAnyUseOfValue(i)) 742 EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap); 743 // If there are no uses, mark the register as dead now, so that 744 // MachineLICM/Sink can see that it's dead. Don't do this if the 745 // node has a Flag value, for the benefit of targets still using 746 // Flag for values in physregs. 747 else if (Node->getValueType(Node->getNumValues()-1) != MVT::Flag) 748 MI->addRegisterDead(Reg, TRI); 749 } 750 } 751 752 // If the instruction has implicit defs and the node doesn't, mark the 753 // implicit def as dead. If the node has any flag outputs, we don't do this 754 // because we don't know what implicit defs are being used by flagged nodes. 755 if (Node->getValueType(Node->getNumValues()-1) != MVT::Flag) 756 if (const unsigned *IDList = II.getImplicitDefs()) { 757 for (unsigned i = NumResults, e = II.getNumDefs()+II.getNumImplicitDefs(); 758 i != e; ++i) 759 MI->addRegisterDead(IDList[i-II.getNumDefs()], TRI); 760 } 761} 762 763/// EmitSpecialNode - Generate machine code for a target-independent node and 764/// needed dependencies. 765void InstrEmitter:: 766EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, 767 DenseMap<SDValue, unsigned> &VRBaseMap) { 768 switch (Node->getOpcode()) { 769 default: 770#ifndef NDEBUG 771 Node->dump(); 772#endif 773 llvm_unreachable("This target-independent node should have been selected!"); 774 break; 775 case ISD::EntryToken: 776 llvm_unreachable("EntryToken should have been excluded from the schedule!"); 777 break; 778 case ISD::MERGE_VALUES: 779 case ISD::TokenFactor: // fall thru 780 break; 781 case ISD::CopyToReg: { 782 unsigned SrcReg; 783 SDValue SrcVal = Node->getOperand(2); 784 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal)) 785 SrcReg = R->getReg(); 786 else 787 SrcReg = getVR(SrcVal, VRBaseMap); 788 789 unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); 790 if (SrcReg == DestReg) // Coalesced away the copy? Ignore. 791 break; 792 793 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 794 DestReg).addReg(SrcReg); 795 break; 796 } 797 case ISD::CopyFromReg: { 798 unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); 799 EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap); 800 break; 801 } 802 case ISD::EH_LABEL: { 803 MCSymbol *S = cast<EHLabelSDNode>(Node)->getLabel(); 804 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), 805 TII->get(TargetOpcode::EH_LABEL)).addSym(S); 806 break; 807 } 808 809 case ISD::INLINEASM: { 810 unsigned NumOps = Node->getNumOperands(); 811 if (Node->getOperand(NumOps-1).getValueType() == MVT::Flag) 812 --NumOps; // Ignore the flag operand. 813 814 // Create the inline asm machine instruction. 815 MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), 816 TII->get(TargetOpcode::INLINEASM)); 817 818 // Add the asm string as an external symbol operand. 819 SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString); 820 const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol(); 821 MI->addOperand(MachineOperand::CreateES(AsmStr)); 822 823 // Add the isAlignStack bit. 824 int64_t isAlignStack = 825 cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_IsAlignStack))-> 826 getZExtValue(); 827 MI->addOperand(MachineOperand::CreateImm(isAlignStack)); 828 829 // Add all of the operand registers to the instruction. 830 for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) { 831 unsigned Flags = 832 cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue(); 833 unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); 834 835 MI->addOperand(MachineOperand::CreateImm(Flags)); 836 ++i; // Skip the ID value. 837 838 switch (InlineAsm::getKind(Flags)) { 839 default: llvm_unreachable("Bad flags!"); 840 case InlineAsm::Kind_RegDef: 841 for (; NumVals; --NumVals, ++i) { 842 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); 843 // FIXME: Add dead flags for physical and virtual registers defined. 844 // For now, mark physical register defs as implicit to help fast 845 // regalloc. This makes inline asm look a lot like calls. 846 MI->addOperand(MachineOperand::CreateReg(Reg, true, 847 /*isImp=*/ TargetRegisterInfo::isPhysicalRegister(Reg))); 848 } 849 break; 850 case InlineAsm::Kind_RegDefEarlyClobber: 851 for (; NumVals; --NumVals, ++i) { 852 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); 853 MI->addOperand(MachineOperand::CreateReg(Reg, /*isDef=*/ true, 854 /*isImp=*/ TargetRegisterInfo::isPhysicalRegister(Reg), 855 /*isKill=*/ false, 856 /*isDead=*/ false, 857 /*isUndef=*/false, 858 /*isEarlyClobber=*/ true)); 859 } 860 break; 861 case InlineAsm::Kind_RegUse: // Use of register. 862 case InlineAsm::Kind_Imm: // Immediate. 863 case InlineAsm::Kind_Mem: // Addressing mode. 864 // The addressing mode has been selected, just add all of the 865 // operands to the machine instruction. 866 for (; NumVals; --NumVals, ++i) 867 AddOperand(MI, Node->getOperand(i), 0, 0, VRBaseMap, 868 /*IsDebug=*/false, IsClone, IsCloned); 869 break; 870 } 871 } 872 873 // Get the mdnode from the asm if it exists and add it to the instruction. 874 SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode); 875 const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD(); 876 if (MD) 877 MI->addOperand(MachineOperand::CreateMetadata(MD)); 878 879 MBB->insert(InsertPos, MI); 880 break; 881 } 882 } 883} 884 885/// InstrEmitter - Construct an InstrEmitter and set it to start inserting 886/// at the given position in the given block. 887InstrEmitter::InstrEmitter(MachineBasicBlock *mbb, 888 MachineBasicBlock::iterator insertpos) 889 : MF(mbb->getParent()), 890 MRI(&MF->getRegInfo()), 891 TM(&MF->getTarget()), 892 TII(TM->getInstrInfo()), 893 TRI(TM->getRegisterInfo()), 894 TLI(TM->getTargetLowering()), 895 MBB(mbb), InsertPos(insertpos) { 896} 897