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/ADT/Statistic.h" 20#include "llvm/CodeGen/MachineConstantPool.h" 21#include "llvm/CodeGen/MachineFunction.h" 22#include "llvm/CodeGen/MachineInstrBuilder.h" 23#include "llvm/CodeGen/MachineRegisterInfo.h" 24#include "llvm/CodeGen/StackMaps.h" 25#include "llvm/IR/DataLayout.h" 26#include "llvm/Support/Debug.h" 27#include "llvm/Support/ErrorHandling.h" 28#include "llvm/Support/MathExtras.h" 29#include "llvm/Target/TargetInstrInfo.h" 30#include "llvm/Target/TargetLowering.h" 31#include "llvm/Target/TargetMachine.h" 32using namespace llvm; 33 34/// MinRCSize - Smallest register class we allow when constraining virtual 35/// registers. If satisfying all register class constraints would require 36/// using a smaller register class, emit a COPY to a new virtual register 37/// instead. 38const unsigned MinRCSize = 4; 39 40/// CountResults - The results of target nodes have register or immediate 41/// operands first, then an optional chain, and optional glue operands (which do 42/// not go into the resulting MachineInstr). 43unsigned InstrEmitter::CountResults(SDNode *Node) { 44 unsigned N = Node->getNumValues(); 45 while (N && Node->getValueType(N - 1) == MVT::Glue) 46 --N; 47 if (N && Node->getValueType(N - 1) == MVT::Other) 48 --N; // Skip over chain result. 49 return N; 50} 51 52/// countOperands - The inputs to target nodes have any actual inputs first, 53/// followed by an optional chain operand, then an optional glue operand. 54/// Compute the number of actual operands that will go into the resulting 55/// MachineInstr. 56/// 57/// Also count physreg RegisterSDNode and RegisterMaskSDNode operands preceding 58/// the chain and glue. These operands may be implicit on the machine instr. 59static unsigned countOperands(SDNode *Node, unsigned NumExpUses, 60 unsigned &NumImpUses) { 61 unsigned N = Node->getNumOperands(); 62 while (N && Node->getOperand(N - 1).getValueType() == MVT::Glue) 63 --N; 64 if (N && Node->getOperand(N - 1).getValueType() == MVT::Other) 65 --N; // Ignore chain if it exists. 66 67 // Count RegisterSDNode and RegisterMaskSDNode operands for NumImpUses. 68 NumImpUses = N - NumExpUses; 69 for (unsigned I = N; I > NumExpUses; --I) { 70 if (isa<RegisterMaskSDNode>(Node->getOperand(I - 1))) 71 continue; 72 if (RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Node->getOperand(I - 1))) 73 if (TargetRegisterInfo::isPhysicalRegister(RN->getReg())) 74 continue; 75 NumImpUses = N - I; 76 break; 77 } 78 79 return N; 80} 81 82/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an 83/// implicit physical register output. 84void InstrEmitter:: 85EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, 86 unsigned SrcReg, DenseMap<SDValue, unsigned> &VRBaseMap) { 87 unsigned VRBase = 0; 88 if (TargetRegisterInfo::isVirtualRegister(SrcReg)) { 89 // Just use the input register directly! 90 SDValue Op(Node, ResNo); 91 if (IsClone) 92 VRBaseMap.erase(Op); 93 bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second; 94 (void)isNew; // Silence compiler warning. 95 assert(isNew && "Node emitted out of order - early"); 96 return; 97 } 98 99 // If the node is only used by a CopyToReg and the dest reg is a vreg, use 100 // the CopyToReg'd destination register instead of creating a new vreg. 101 bool MatchReg = true; 102 const TargetRegisterClass *UseRC = NULL; 103 MVT VT = Node->getSimpleValueType(ResNo); 104 105 // Stick to the preferred register classes for legal types. 106 if (TLI->isTypeLegal(VT)) 107 UseRC = TLI->getRegClassFor(VT); 108 109 if (!IsClone && !IsCloned) 110 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 111 UI != E; ++UI) { 112 SDNode *User = *UI; 113 bool Match = true; 114 if (User->getOpcode() == ISD::CopyToReg && 115 User->getOperand(2).getNode() == Node && 116 User->getOperand(2).getResNo() == ResNo) { 117 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 118 if (TargetRegisterInfo::isVirtualRegister(DestReg)) { 119 VRBase = DestReg; 120 Match = false; 121 } else if (DestReg != SrcReg) 122 Match = false; 123 } else { 124 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { 125 SDValue Op = User->getOperand(i); 126 if (Op.getNode() != Node || Op.getResNo() != ResNo) 127 continue; 128 MVT VT = Node->getSimpleValueType(Op.getResNo()); 129 if (VT == MVT::Other || VT == MVT::Glue) 130 continue; 131 Match = false; 132 if (User->isMachineOpcode()) { 133 const MCInstrDesc &II = TII->get(User->getMachineOpcode()); 134 const TargetRegisterClass *RC = 0; 135 if (i+II.getNumDefs() < II.getNumOperands()) { 136 RC = TRI->getAllocatableClass( 137 TII->getRegClass(II, i+II.getNumDefs(), TRI, *MF)); 138 } 139 if (!UseRC) 140 UseRC = RC; 141 else if (RC) { 142 const TargetRegisterClass *ComRC = 143 TRI->getCommonSubClass(UseRC, RC); 144 // If multiple uses expect disjoint register classes, we emit 145 // copies in AddRegisterOperand. 146 if (ComRC) 147 UseRC = ComRC; 148 } 149 } 150 } 151 } 152 MatchReg &= Match; 153 if (VRBase) 154 break; 155 } 156 157 const TargetRegisterClass *SrcRC = 0, *DstRC = 0; 158 SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT); 159 160 // Figure out the register class to create for the destreg. 161 if (VRBase) { 162 DstRC = MRI->getRegClass(VRBase); 163 } else if (UseRC) { 164 assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!"); 165 DstRC = UseRC; 166 } else { 167 DstRC = TLI->getRegClassFor(VT); 168 } 169 170 // If all uses are reading from the src physical register and copying the 171 // register is either impossible or very expensive, then don't create a copy. 172 if (MatchReg && SrcRC->getCopyCost() < 0) { 173 VRBase = SrcReg; 174 } else { 175 // Create the reg, emit the copy. 176 VRBase = MRI->createVirtualRegister(DstRC); 177 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 178 VRBase).addReg(SrcReg); 179 } 180 181 SDValue Op(Node, ResNo); 182 if (IsClone) 183 VRBaseMap.erase(Op); 184 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 185 (void)isNew; // Silence compiler warning. 186 assert(isNew && "Node emitted out of order - early"); 187} 188 189/// getDstOfCopyToRegUse - If the only use of the specified result number of 190/// node is a CopyToReg, return its destination register. Return 0 otherwise. 191unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node, 192 unsigned ResNo) const { 193 if (!Node->hasOneUse()) 194 return 0; 195 196 SDNode *User = *Node->use_begin(); 197 if (User->getOpcode() == ISD::CopyToReg && 198 User->getOperand(2).getNode() == Node && 199 User->getOperand(2).getResNo() == ResNo) { 200 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 201 if (TargetRegisterInfo::isVirtualRegister(Reg)) 202 return Reg; 203 } 204 return 0; 205} 206 207void InstrEmitter::CreateVirtualRegisters(SDNode *Node, 208 MachineInstrBuilder &MIB, 209 const MCInstrDesc &II, 210 bool IsClone, bool IsCloned, 211 DenseMap<SDValue, unsigned> &VRBaseMap) { 212 assert(Node->getMachineOpcode() != TargetOpcode::IMPLICIT_DEF && 213 "IMPLICIT_DEF should have been handled as a special case elsewhere!"); 214 215 unsigned NumResults = CountResults(Node); 216 for (unsigned i = 0; i < II.getNumDefs(); ++i) { 217 // If the specific node value is only used by a CopyToReg and the dest reg 218 // is a vreg in the same register class, use the CopyToReg'd destination 219 // register instead of creating a new vreg. 220 unsigned VRBase = 0; 221 const TargetRegisterClass *RC = 222 TRI->getAllocatableClass(TII->getRegClass(II, i, TRI, *MF)); 223 // Always let the value type influence the used register class. The 224 // constraints on the instruction may be too lax to represent the value 225 // type correctly. For example, a 64-bit float (X86::FR64) can't live in 226 // the 32-bit float super-class (X86::FR32). 227 if (i < NumResults && TLI->isTypeLegal(Node->getSimpleValueType(i))) { 228 const TargetRegisterClass *VTRC = 229 TLI->getRegClassFor(Node->getSimpleValueType(i)); 230 if (RC) 231 VTRC = TRI->getCommonSubClass(RC, VTRC); 232 if (VTRC) 233 RC = VTRC; 234 } 235 236 if (II.OpInfo[i].isOptionalDef()) { 237 // Optional def must be a physical register. 238 unsigned NumResults = CountResults(Node); 239 VRBase = cast<RegisterSDNode>(Node->getOperand(i-NumResults))->getReg(); 240 assert(TargetRegisterInfo::isPhysicalRegister(VRBase)); 241 MIB.addReg(VRBase, RegState::Define); 242 } 243 244 if (!VRBase && !IsClone && !IsCloned) 245 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 246 UI != E; ++UI) { 247 SDNode *User = *UI; 248 if (User->getOpcode() == ISD::CopyToReg && 249 User->getOperand(2).getNode() == Node && 250 User->getOperand(2).getResNo() == i) { 251 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 252 if (TargetRegisterInfo::isVirtualRegister(Reg)) { 253 const TargetRegisterClass *RegRC = MRI->getRegClass(Reg); 254 if (RegRC == RC) { 255 VRBase = Reg; 256 MIB.addReg(VRBase, RegState::Define); 257 break; 258 } 259 } 260 } 261 } 262 263 // Create the result registers for this node and add the result regs to 264 // the machine instruction. 265 if (VRBase == 0) { 266 assert(RC && "Isn't a register operand!"); 267 VRBase = MRI->createVirtualRegister(RC); 268 MIB.addReg(VRBase, RegState::Define); 269 } 270 271 SDValue Op(Node, i); 272 if (IsClone) 273 VRBaseMap.erase(Op); 274 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 275 (void)isNew; // Silence compiler warning. 276 assert(isNew && "Node emitted out of order - early"); 277 } 278} 279 280/// getVR - Return the virtual register corresponding to the specified result 281/// of the specified node. 282unsigned InstrEmitter::getVR(SDValue Op, 283 DenseMap<SDValue, unsigned> &VRBaseMap) { 284 if (Op.isMachineOpcode() && 285 Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) { 286 // Add an IMPLICIT_DEF instruction before every use. 287 unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo()); 288 // IMPLICIT_DEF can produce any type of result so its MCInstrDesc 289 // does not include operand register class info. 290 if (!VReg) { 291 const TargetRegisterClass *RC = 292 TLI->getRegClassFor(Op.getSimpleValueType()); 293 VReg = MRI->createVirtualRegister(RC); 294 } 295 BuildMI(*MBB, InsertPos, Op.getDebugLoc(), 296 TII->get(TargetOpcode::IMPLICIT_DEF), VReg); 297 return VReg; 298 } 299 300 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); 301 assert(I != VRBaseMap.end() && "Node emitted out of order - late"); 302 return I->second; 303} 304 305 306/// AddRegisterOperand - Add the specified register as an operand to the 307/// specified machine instr. Insert register copies if the register is 308/// not in the required register class. 309void 310InstrEmitter::AddRegisterOperand(MachineInstrBuilder &MIB, 311 SDValue Op, 312 unsigned IIOpNum, 313 const MCInstrDesc *II, 314 DenseMap<SDValue, unsigned> &VRBaseMap, 315 bool IsDebug, bool IsClone, bool IsCloned) { 316 assert(Op.getValueType() != MVT::Other && 317 Op.getValueType() != MVT::Glue && 318 "Chain and glue operands should occur at end of operand list!"); 319 // Get/emit the operand. 320 unsigned VReg = getVR(Op, VRBaseMap); 321 assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?"); 322 323 const MCInstrDesc &MCID = MIB->getDesc(); 324 bool isOptDef = IIOpNum < MCID.getNumOperands() && 325 MCID.OpInfo[IIOpNum].isOptionalDef(); 326 327 // If the instruction requires a register in a different class, create 328 // a new virtual register and copy the value into it, but first attempt to 329 // shrink VReg's register class within reason. For example, if VReg == GR32 330 // and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP. 331 if (II) { 332 const TargetRegisterClass *DstRC = 0; 333 if (IIOpNum < II->getNumOperands()) 334 DstRC = TRI->getAllocatableClass(TII->getRegClass(*II,IIOpNum,TRI,*MF)); 335 if (DstRC && !MRI->constrainRegClass(VReg, DstRC, MinRCSize)) { 336 unsigned NewVReg = MRI->createVirtualRegister(DstRC); 337 BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(), 338 TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg); 339 VReg = NewVReg; 340 } 341 } 342 343 // If this value has only one use, that use is a kill. This is a 344 // conservative approximation. InstrEmitter does trivial coalescing 345 // with CopyFromReg nodes, so don't emit kill flags for them. 346 // Avoid kill flags on Schedule cloned nodes, since there will be 347 // multiple uses. 348 // Tied operands are never killed, so we need to check that. And that 349 // means we need to determine the index of the operand. 350 bool isKill = Op.hasOneUse() && 351 Op.getNode()->getOpcode() != ISD::CopyFromReg && 352 !IsDebug && 353 !(IsClone || IsCloned); 354 if (isKill) { 355 unsigned Idx = MIB->getNumOperands(); 356 while (Idx > 0 && 357 MIB->getOperand(Idx-1).isReg() && 358 MIB->getOperand(Idx-1).isImplicit()) 359 --Idx; 360 bool isTied = MCID.getOperandConstraint(Idx, MCOI::TIED_TO) != -1; 361 if (isTied) 362 isKill = false; 363 } 364 365 MIB.addReg(VReg, getDefRegState(isOptDef) | getKillRegState(isKill) | 366 getDebugRegState(IsDebug)); 367} 368 369/// AddOperand - Add the specified operand to the specified machine instr. II 370/// specifies the instruction information for the node, and IIOpNum is the 371/// operand number (in the II) that we are adding. 372void InstrEmitter::AddOperand(MachineInstrBuilder &MIB, 373 SDValue Op, 374 unsigned IIOpNum, 375 const MCInstrDesc *II, 376 DenseMap<SDValue, unsigned> &VRBaseMap, 377 bool IsDebug, bool IsClone, bool IsCloned) { 378 if (Op.isMachineOpcode()) { 379 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap, 380 IsDebug, IsClone, IsCloned); 381 } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) { 382 MIB.addImm(C->getSExtValue()); 383 } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) { 384 MIB.addFPImm(F->getConstantFPValue()); 385 } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) { 386 // Turn additional physreg operands into implicit uses on non-variadic 387 // instructions. This is used by call and return instructions passing 388 // arguments in registers. 389 bool Imp = II && (IIOpNum >= II->getNumOperands() && !II->isVariadic()); 390 MIB.addReg(R->getReg(), getImplRegState(Imp)); 391 } else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) { 392 MIB.addRegMask(RM->getRegMask()); 393 } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) { 394 MIB.addGlobalAddress(TGA->getGlobal(), TGA->getOffset(), 395 TGA->getTargetFlags()); 396 } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) { 397 MIB.addMBB(BBNode->getBasicBlock()); 398 } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) { 399 MIB.addFrameIndex(FI->getIndex()); 400 } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) { 401 MIB.addJumpTableIndex(JT->getIndex(), JT->getTargetFlags()); 402 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) { 403 int Offset = CP->getOffset(); 404 unsigned Align = CP->getAlignment(); 405 Type *Type = CP->getType(); 406 // MachineConstantPool wants an explicit alignment. 407 if (Align == 0) { 408 Align = TM->getDataLayout()->getPrefTypeAlignment(Type); 409 if (Align == 0) { 410 // Alignment of vector types. FIXME! 411 Align = TM->getDataLayout()->getTypeAllocSize(Type); 412 } 413 } 414 415 unsigned Idx; 416 MachineConstantPool *MCP = MF->getConstantPool(); 417 if (CP->isMachineConstantPoolEntry()) 418 Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align); 419 else 420 Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align); 421 MIB.addConstantPoolIndex(Idx, Offset, CP->getTargetFlags()); 422 } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) { 423 MIB.addExternalSymbol(ES->getSymbol(), ES->getTargetFlags()); 424 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) { 425 MIB.addBlockAddress(BA->getBlockAddress(), 426 BA->getOffset(), 427 BA->getTargetFlags()); 428 } else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) { 429 MIB.addTargetIndex(TI->getIndex(), TI->getOffset(), TI->getTargetFlags()); 430 } else { 431 assert(Op.getValueType() != MVT::Other && 432 Op.getValueType() != MVT::Glue && 433 "Chain and glue operands should occur at end of operand list!"); 434 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap, 435 IsDebug, IsClone, IsCloned); 436 } 437} 438 439unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx, 440 MVT VT, DebugLoc DL) { 441 const TargetRegisterClass *VRC = MRI->getRegClass(VReg); 442 const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx); 443 444 // RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg 445 // within reason. 446 if (RC && RC != VRC) 447 RC = MRI->constrainRegClass(VReg, RC, MinRCSize); 448 449 // VReg has been adjusted. It can be used with SubIdx operands now. 450 if (RC) 451 return VReg; 452 453 // VReg couldn't be reasonably constrained. Emit a COPY to a new virtual 454 // register instead. 455 RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx); 456 assert(RC && "No legal register class for VT supports that SubIdx"); 457 unsigned NewReg = MRI->createVirtualRegister(RC); 458 BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg) 459 .addReg(VReg); 460 return NewReg; 461} 462 463/// EmitSubregNode - Generate machine code for subreg nodes. 464/// 465void InstrEmitter::EmitSubregNode(SDNode *Node, 466 DenseMap<SDValue, unsigned> &VRBaseMap, 467 bool IsClone, bool IsCloned) { 468 unsigned VRBase = 0; 469 unsigned Opc = Node->getMachineOpcode(); 470 471 // If the node is only used by a CopyToReg and the dest reg is a vreg, use 472 // the CopyToReg'd destination register instead of creating a new vreg. 473 for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); 474 UI != E; ++UI) { 475 SDNode *User = *UI; 476 if (User->getOpcode() == ISD::CopyToReg && 477 User->getOperand(2).getNode() == Node) { 478 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); 479 if (TargetRegisterInfo::isVirtualRegister(DestReg)) { 480 VRBase = DestReg; 481 break; 482 } 483 } 484 } 485 486 if (Opc == TargetOpcode::EXTRACT_SUBREG) { 487 // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no 488 // constraints on the %dst register, COPY can target all legal register 489 // classes. 490 unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); 491 const TargetRegisterClass *TRC = 492 TLI->getRegClassFor(Node->getSimpleValueType(0)); 493 494 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); 495 MachineInstr *DefMI = MRI->getVRegDef(VReg); 496 unsigned SrcReg, DstReg, DefSubIdx; 497 if (DefMI && 498 TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) && 499 SubIdx == DefSubIdx && 500 TRC == MRI->getRegClass(SrcReg)) { 501 // Optimize these: 502 // r1025 = s/zext r1024, 4 503 // r1026 = extract_subreg r1025, 4 504 // to a copy 505 // r1026 = copy r1024 506 VRBase = MRI->createVirtualRegister(TRC); 507 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), 508 TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg); 509 MRI->clearKillFlags(SrcReg); 510 } else { 511 // VReg may not support a SubIdx sub-register, and we may need to 512 // constrain its register class or issue a COPY to a compatible register 513 // class. 514 VReg = ConstrainForSubReg(VReg, SubIdx, 515 Node->getOperand(0).getSimpleValueType(), 516 Node->getDebugLoc()); 517 518 // Create the destreg if it is missing. 519 if (VRBase == 0) 520 VRBase = MRI->createVirtualRegister(TRC); 521 522 // Create the extract_subreg machine instruction. 523 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), 524 TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx); 525 } 526 } else if (Opc == TargetOpcode::INSERT_SUBREG || 527 Opc == TargetOpcode::SUBREG_TO_REG) { 528 SDValue N0 = Node->getOperand(0); 529 SDValue N1 = Node->getOperand(1); 530 SDValue N2 = Node->getOperand(2); 531 unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue(); 532 533 // Figure out the register class to create for the destreg. It should be 534 // the largest legal register class supporting SubIdx sub-registers. 535 // RegisterCoalescer will constrain it further if it decides to eliminate 536 // the INSERT_SUBREG instruction. 537 // 538 // %dst = INSERT_SUBREG %src, %sub, SubIdx 539 // 540 // is lowered by TwoAddressInstructionPass to: 541 // 542 // %dst = COPY %src 543 // %dst:SubIdx = COPY %sub 544 // 545 // There is no constraint on the %src register class. 546 // 547 const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getSimpleValueType(0)); 548 SRC = TRI->getSubClassWithSubReg(SRC, SubIdx); 549 assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG"); 550 551 if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase))) 552 VRBase = MRI->createVirtualRegister(SRC); 553 554 // Create the insert_subreg or subreg_to_reg machine instruction. 555 MachineInstrBuilder MIB = 556 BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc), VRBase); 557 558 // If creating a subreg_to_reg, then the first input operand 559 // is an implicit value immediate, otherwise it's a register 560 if (Opc == TargetOpcode::SUBREG_TO_REG) { 561 const ConstantSDNode *SD = cast<ConstantSDNode>(N0); 562 MIB.addImm(SD->getZExtValue()); 563 } else 564 AddOperand(MIB, N0, 0, 0, VRBaseMap, /*IsDebug=*/false, 565 IsClone, IsCloned); 566 // Add the subregster being inserted 567 AddOperand(MIB, N1, 0, 0, VRBaseMap, /*IsDebug=*/false, 568 IsClone, IsCloned); 569 MIB.addImm(SubIdx); 570 MBB->insert(InsertPos, MIB); 571 } else 572 llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg"); 573 574 SDValue Op(Node, 0); 575 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; 576 (void)isNew; // Silence compiler warning. 577 assert(isNew && "Node emitted out of order - early"); 578} 579 580/// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes. 581/// COPY_TO_REGCLASS is just a normal copy, except that the destination 582/// register is constrained to be in a particular register class. 583/// 584void 585InstrEmitter::EmitCopyToRegClassNode(SDNode *Node, 586 DenseMap<SDValue, unsigned> &VRBaseMap) { 587 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); 588 589 // Create the new VReg in the destination class and emit a copy. 590 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); 591 const TargetRegisterClass *DstRC = 592 TRI->getAllocatableClass(TRI->getRegClass(DstRCIdx)); 593 unsigned NewVReg = MRI->createVirtualRegister(DstRC); 594 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 595 NewVReg).addReg(VReg); 596 597 SDValue Op(Node, 0); 598 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; 599 (void)isNew; // Silence compiler warning. 600 assert(isNew && "Node emitted out of order - early"); 601} 602 603/// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes. 604/// 605void InstrEmitter::EmitRegSequence(SDNode *Node, 606 DenseMap<SDValue, unsigned> &VRBaseMap, 607 bool IsClone, bool IsCloned) { 608 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue(); 609 const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx); 610 unsigned NewVReg = MRI->createVirtualRegister(TRI->getAllocatableClass(RC)); 611 const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE); 612 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II, NewVReg); 613 unsigned NumOps = Node->getNumOperands(); 614 assert((NumOps & 1) == 1 && 615 "REG_SEQUENCE must have an odd number of operands!"); 616 for (unsigned i = 1; i != NumOps; ++i) { 617 SDValue Op = Node->getOperand(i); 618 if ((i & 1) == 0) { 619 RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1)); 620 // Skip physical registers as they don't have a vreg to get and we'll 621 // insert copies for them in TwoAddressInstructionPass anyway. 622 if (!R || !TargetRegisterInfo::isPhysicalRegister(R->getReg())) { 623 unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue(); 624 unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap); 625 const TargetRegisterClass *TRC = MRI->getRegClass(SubReg); 626 const TargetRegisterClass *SRC = 627 TRI->getMatchingSuperRegClass(RC, TRC, SubIdx); 628 if (SRC && SRC != RC) { 629 MRI->setRegClass(NewVReg, SRC); 630 RC = SRC; 631 } 632 } 633 } 634 AddOperand(MIB, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false, 635 IsClone, IsCloned); 636 } 637 638 MBB->insert(InsertPos, MIB); 639 SDValue Op(Node, 0); 640 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; 641 (void)isNew; // Silence compiler warning. 642 assert(isNew && "Node emitted out of order - early"); 643} 644 645/// EmitDbgValue - Generate machine instruction for a dbg_value node. 646/// 647MachineInstr * 648InstrEmitter::EmitDbgValue(SDDbgValue *SD, 649 DenseMap<SDValue, unsigned> &VRBaseMap) { 650 uint64_t Offset = SD->getOffset(); 651 MDNode* MDPtr = SD->getMDPtr(); 652 DebugLoc DL = SD->getDebugLoc(); 653 654 if (SD->getKind() == SDDbgValue::FRAMEIX) { 655 // Stack address; this needs to be lowered in target-dependent fashion. 656 // EmitTargetCodeForFrameDebugValue is responsible for allocation. 657 return BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE)) 658 .addFrameIndex(SD->getFrameIx()).addImm(Offset).addMetadata(MDPtr); 659 } 660 // Otherwise, we're going to create an instruction here. 661 const MCInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE); 662 MachineInstrBuilder MIB = BuildMI(*MF, DL, II); 663 if (SD->getKind() == SDDbgValue::SDNODE) { 664 SDNode *Node = SD->getSDNode(); 665 SDValue Op = SDValue(Node, SD->getResNo()); 666 // It's possible we replaced this SDNode with other(s) and therefore 667 // didn't generate code for it. It's better to catch these cases where 668 // they happen and transfer the debug info, but trying to guarantee that 669 // in all cases would be very fragile; this is a safeguard for any 670 // that were missed. 671 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); 672 if (I==VRBaseMap.end()) 673 MIB.addReg(0U); // undef 674 else 675 AddOperand(MIB, Op, (*MIB).getNumOperands(), &II, VRBaseMap, 676 /*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false); 677 } else if (SD->getKind() == SDDbgValue::CONST) { 678 const Value *V = SD->getConst(); 679 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 680 if (CI->getBitWidth() > 64) 681 MIB.addCImm(CI); 682 else 683 MIB.addImm(CI->getSExtValue()); 684 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) { 685 MIB.addFPImm(CF); 686 } else { 687 // Could be an Undef. In any case insert an Undef so we can see what we 688 // dropped. 689 MIB.addReg(0U); 690 } 691 } else { 692 // Insert an Undef so we can see what we dropped. 693 MIB.addReg(0U); 694 } 695 696 if (Offset != 0) // Indirect addressing. 697 MIB.addImm(Offset); 698 else 699 MIB.addReg(0U, RegState::Debug); 700 701 MIB.addMetadata(MDPtr); 702 703 return &*MIB; 704} 705 706/// EmitMachineNode - Generate machine code for a target-specific node and 707/// needed dependencies. 708/// 709void InstrEmitter:: 710EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, 711 DenseMap<SDValue, unsigned> &VRBaseMap) { 712 unsigned Opc = Node->getMachineOpcode(); 713 714 // Handle subreg insert/extract specially 715 if (Opc == TargetOpcode::EXTRACT_SUBREG || 716 Opc == TargetOpcode::INSERT_SUBREG || 717 Opc == TargetOpcode::SUBREG_TO_REG) { 718 EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned); 719 return; 720 } 721 722 // Handle COPY_TO_REGCLASS specially. 723 if (Opc == TargetOpcode::COPY_TO_REGCLASS) { 724 EmitCopyToRegClassNode(Node, VRBaseMap); 725 return; 726 } 727 728 // Handle REG_SEQUENCE specially. 729 if (Opc == TargetOpcode::REG_SEQUENCE) { 730 EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned); 731 return; 732 } 733 734 if (Opc == TargetOpcode::IMPLICIT_DEF) 735 // We want a unique VR for each IMPLICIT_DEF use. 736 return; 737 738 const MCInstrDesc &II = TII->get(Opc); 739 unsigned NumResults = CountResults(Node); 740 unsigned NumDefs = II.getNumDefs(); 741 const uint16_t *ScratchRegs = NULL; 742 743 // Handle PATCHPOINT specially and then use the generic code. 744 if (Opc == TargetOpcode::PATCHPOINT) { 745 unsigned CC = Node->getConstantOperandVal(PatchPointOpers::CCPos); 746 NumDefs = NumResults; 747 ScratchRegs = TLI->getScratchRegisters((CallingConv::ID) CC); 748 } 749 750 unsigned NumImpUses = 0; 751 unsigned NodeOperands = 752 countOperands(Node, II.getNumOperands() - NumDefs, NumImpUses); 753 bool HasPhysRegOuts = NumResults > NumDefs && II.getImplicitDefs()!=0; 754#ifndef NDEBUG 755 unsigned NumMIOperands = NodeOperands + NumResults; 756 if (II.isVariadic()) 757 assert(NumMIOperands >= II.getNumOperands() && 758 "Too few operands for a variadic node!"); 759 else 760 assert(NumMIOperands >= II.getNumOperands() && 761 NumMIOperands <= II.getNumOperands() + II.getNumImplicitDefs() + 762 NumImpUses && 763 "#operands for dag node doesn't match .td file!"); 764#endif 765 766 // Create the new machine instruction. 767 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II); 768 769 // Add result register values for things that are defined by this 770 // instruction. 771 if (NumResults) 772 CreateVirtualRegisters(Node, MIB, II, IsClone, IsCloned, VRBaseMap); 773 774 // Emit all of the actual operands of this instruction, adding them to the 775 // instruction as appropriate. 776 bool HasOptPRefs = NumDefs > NumResults; 777 assert((!HasOptPRefs || !HasPhysRegOuts) && 778 "Unable to cope with optional defs and phys regs defs!"); 779 unsigned NumSkip = HasOptPRefs ? NumDefs - NumResults : 0; 780 for (unsigned i = NumSkip; i != NodeOperands; ++i) 781 AddOperand(MIB, Node->getOperand(i), i-NumSkip+NumDefs, &II, 782 VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned); 783 784 // Add scratch registers as implicit def and early clobber 785 if (ScratchRegs) 786 for (unsigned i = 0; ScratchRegs[i]; ++i) 787 MIB.addReg(ScratchRegs[i], RegState::ImplicitDefine | 788 RegState::EarlyClobber); 789 790 // Transfer all of the memory reference descriptions of this instruction. 791 MIB.setMemRefs(cast<MachineSDNode>(Node)->memoperands_begin(), 792 cast<MachineSDNode>(Node)->memoperands_end()); 793 794 // Insert the instruction into position in the block. This needs to 795 // happen before any custom inserter hook is called so that the 796 // hook knows where in the block to insert the replacement code. 797 MBB->insert(InsertPos, MIB); 798 799 // The MachineInstr may also define physregs instead of virtregs. These 800 // physreg values can reach other instructions in different ways: 801 // 802 // 1. When there is a use of a Node value beyond the explicitly defined 803 // virtual registers, we emit a CopyFromReg for one of the implicitly 804 // defined physregs. This only happens when HasPhysRegOuts is true. 805 // 806 // 2. A CopyFromReg reading a physreg may be glued to this instruction. 807 // 808 // 3. A glued instruction may implicitly use a physreg. 809 // 810 // 4. A glued instruction may use a RegisterSDNode operand. 811 // 812 // Collect all the used physreg defs, and make sure that any unused physreg 813 // defs are marked as dead. 814 SmallVector<unsigned, 8> UsedRegs; 815 816 // Additional results must be physical register defs. 817 if (HasPhysRegOuts) { 818 for (unsigned i = NumDefs; i < NumResults; ++i) { 819 unsigned Reg = II.getImplicitDefs()[i - NumDefs]; 820 if (!Node->hasAnyUseOfValue(i)) 821 continue; 822 // This implicitly defined physreg has a use. 823 UsedRegs.push_back(Reg); 824 EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap); 825 } 826 } 827 828 // Scan the glue chain for any used physregs. 829 if (Node->getValueType(Node->getNumValues()-1) == MVT::Glue) { 830 for (SDNode *F = Node->getGluedUser(); F; F = F->getGluedUser()) { 831 if (F->getOpcode() == ISD::CopyFromReg) { 832 UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg()); 833 continue; 834 } else if (F->getOpcode() == ISD::CopyToReg) { 835 // Skip CopyToReg nodes that are internal to the glue chain. 836 continue; 837 } 838 // Collect declared implicit uses. 839 const MCInstrDesc &MCID = TII->get(F->getMachineOpcode()); 840 UsedRegs.append(MCID.getImplicitUses(), 841 MCID.getImplicitUses() + MCID.getNumImplicitUses()); 842 // In addition to declared implicit uses, we must also check for 843 // direct RegisterSDNode operands. 844 for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i) 845 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) { 846 unsigned Reg = R->getReg(); 847 if (TargetRegisterInfo::isPhysicalRegister(Reg)) 848 UsedRegs.push_back(Reg); 849 } 850 } 851 } 852 853 // Finally mark unused registers as dead. 854 if (!UsedRegs.empty() || II.getImplicitDefs()) 855 MIB->setPhysRegsDeadExcept(UsedRegs, *TRI); 856 857 // Run post-isel target hook to adjust this instruction if needed. 858#ifdef NDEBUG 859 if (II.hasPostISelHook()) 860#endif 861 TLI->AdjustInstrPostInstrSelection(MIB, Node); 862} 863 864/// EmitSpecialNode - Generate machine code for a target-independent node and 865/// needed dependencies. 866void InstrEmitter:: 867EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, 868 DenseMap<SDValue, unsigned> &VRBaseMap) { 869 switch (Node->getOpcode()) { 870 default: 871#ifndef NDEBUG 872 Node->dump(); 873#endif 874 llvm_unreachable("This target-independent node should have been selected!"); 875 case ISD::EntryToken: 876 llvm_unreachable("EntryToken should have been excluded from the schedule!"); 877 case ISD::MERGE_VALUES: 878 case ISD::TokenFactor: // fall thru 879 break; 880 case ISD::CopyToReg: { 881 unsigned SrcReg; 882 SDValue SrcVal = Node->getOperand(2); 883 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal)) 884 SrcReg = R->getReg(); 885 else 886 SrcReg = getVR(SrcVal, VRBaseMap); 887 888 unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); 889 if (SrcReg == DestReg) // Coalesced away the copy? Ignore. 890 break; 891 892 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), 893 DestReg).addReg(SrcReg); 894 break; 895 } 896 case ISD::CopyFromReg: { 897 unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); 898 EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap); 899 break; 900 } 901 case ISD::EH_LABEL: { 902 MCSymbol *S = cast<EHLabelSDNode>(Node)->getLabel(); 903 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), 904 TII->get(TargetOpcode::EH_LABEL)).addSym(S); 905 break; 906 } 907 908 case ISD::LIFETIME_START: 909 case ISD::LIFETIME_END: { 910 unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START) ? 911 TargetOpcode::LIFETIME_START : TargetOpcode::LIFETIME_END; 912 913 FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Node->getOperand(1)); 914 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp)) 915 .addFrameIndex(FI->getIndex()); 916 break; 917 } 918 919 case ISD::INLINEASM: { 920 unsigned NumOps = Node->getNumOperands(); 921 if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue) 922 --NumOps; // Ignore the glue operand. 923 924 // Create the inline asm machine instruction. 925 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), 926 TII->get(TargetOpcode::INLINEASM)); 927 928 // Add the asm string as an external symbol operand. 929 SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString); 930 const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol(); 931 MIB.addExternalSymbol(AsmStr); 932 933 // Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore 934 // bits. 935 int64_t ExtraInfo = 936 cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))-> 937 getZExtValue(); 938 MIB.addImm(ExtraInfo); 939 940 // Remember to operand index of the group flags. 941 SmallVector<unsigned, 8> GroupIdx; 942 943 // Add all of the operand registers to the instruction. 944 for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) { 945 unsigned Flags = 946 cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue(); 947 const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); 948 949 GroupIdx.push_back(MIB->getNumOperands()); 950 MIB.addImm(Flags); 951 ++i; // Skip the ID value. 952 953 switch (InlineAsm::getKind(Flags)) { 954 default: llvm_unreachable("Bad flags!"); 955 case InlineAsm::Kind_RegDef: 956 for (unsigned j = 0; j != NumVals; ++j, ++i) { 957 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); 958 // FIXME: Add dead flags for physical and virtual registers defined. 959 // For now, mark physical register defs as implicit to help fast 960 // regalloc. This makes inline asm look a lot like calls. 961 MIB.addReg(Reg, RegState::Define | 962 getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); 963 } 964 break; 965 case InlineAsm::Kind_RegDefEarlyClobber: 966 case InlineAsm::Kind_Clobber: 967 for (unsigned j = 0; j != NumVals; ++j, ++i) { 968 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); 969 MIB.addReg(Reg, RegState::Define | RegState::EarlyClobber | 970 getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); 971 } 972 break; 973 case InlineAsm::Kind_RegUse: // Use of register. 974 case InlineAsm::Kind_Imm: // Immediate. 975 case InlineAsm::Kind_Mem: // Addressing mode. 976 // The addressing mode has been selected, just add all of the 977 // operands to the machine instruction. 978 for (unsigned j = 0; j != NumVals; ++j, ++i) 979 AddOperand(MIB, Node->getOperand(i), 0, 0, VRBaseMap, 980 /*IsDebug=*/false, IsClone, IsCloned); 981 982 // Manually set isTied bits. 983 if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) { 984 unsigned DefGroup = 0; 985 if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) { 986 unsigned DefIdx = GroupIdx[DefGroup] + 1; 987 unsigned UseIdx = GroupIdx.back() + 1; 988 for (unsigned j = 0; j != NumVals; ++j) 989 MIB->tieOperands(DefIdx + j, UseIdx + j); 990 } 991 } 992 break; 993 } 994 } 995 996 // Get the mdnode from the asm if it exists and add it to the instruction. 997 SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode); 998 const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD(); 999 if (MD) 1000 MIB.addMetadata(MD); 1001 1002 MBB->insert(InsertPos, MIB); 1003 break; 1004 } 1005 } 1006} 1007 1008/// InstrEmitter - Construct an InstrEmitter and set it to start inserting 1009/// at the given position in the given block. 1010InstrEmitter::InstrEmitter(MachineBasicBlock *mbb, 1011 MachineBasicBlock::iterator insertpos) 1012 : MF(mbb->getParent()), 1013 MRI(&MF->getRegInfo()), 1014 TM(&MF->getTarget()), 1015 TII(TM->getInstrInfo()), 1016 TRI(TM->getRegisterInfo()), 1017 TLI(TM->getTargetLowering()), 1018 MBB(mbb), InsertPos(insertpos) { 1019} 1020