1 //==--- InstrEmitter.cpp - Emit MachineInstrs for the SelectionDAG class ---==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This implements the Emit routines for the SelectionDAG class, which creates
11 // MachineInstrs based on the decisions of the SelectionDAG instruction
14 //===----------------------------------------------------------------------===//
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"
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
38 const unsigned MinRCSize = 4;
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).
43 unsigned InstrEmitter::CountResults(SDNode *Node) {
44 unsigned N = Node->getNumValues();
45 while (N && Node->getValueType(N - 1) == MVT::Glue)
47 if (N && Node->getValueType(N - 1) == MVT::Other)
48 --N; // Skip over chain result.
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
57 /// Also count physreg RegisterSDNode and RegisterMaskSDNode operands preceding
58 /// the chain and glue. These operands may be implicit on the machine instr.
59 static unsigned countOperands(SDNode *Node, unsigned NumExpUses,
60 unsigned &NumImpUses) {
61 unsigned N = Node->getNumOperands();
62 while (N && Node->getOperand(N - 1).getValueType() == MVT::Glue)
64 if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
65 --N; // Ignore chain if it exists.
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)))
72 if (RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Node->getOperand(I - 1)))
73 if (TargetRegisterInfo::isPhysicalRegister(RN->getReg()))
82 /// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
83 /// implicit physical register output.
85 EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
86 unsigned SrcReg, DenseMap<SDValue, unsigned> &VRBaseMap) {
88 if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
89 // Just use the input register directly!
90 SDValue Op(Node, ResNo);
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");
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 = nullptr;
103 MVT VT = Node->getSimpleValueType(ResNo);
105 // Stick to the preferred register classes for legal types.
106 if (TLI->isTypeLegal(VT))
107 UseRC = TLI->getRegClassFor(VT);
109 if (!IsClone && !IsCloned)
110 for (SDNode *User : Node->uses()) {
112 if (User->getOpcode() == ISD::CopyToReg &&
113 User->getOperand(2).getNode() == Node &&
114 User->getOperand(2).getResNo() == ResNo) {
115 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
116 if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
119 } else if (DestReg != SrcReg)
122 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
123 SDValue Op = User->getOperand(i);
124 if (Op.getNode() != Node || Op.getResNo() != ResNo)
126 MVT VT = Node->getSimpleValueType(Op.getResNo());
127 if (VT == MVT::Other || VT == MVT::Glue)
130 if (User->isMachineOpcode()) {
131 const MCInstrDesc &II = TII->get(User->getMachineOpcode());
132 const TargetRegisterClass *RC = nullptr;
133 if (i+II.getNumDefs() < II.getNumOperands()) {
134 RC = TRI->getAllocatableClass(
135 TII->getRegClass(II, i+II.getNumDefs(), TRI, *MF));
140 const TargetRegisterClass *ComRC =
141 TRI->getCommonSubClass(UseRC, RC);
142 // If multiple uses expect disjoint register classes, we emit
143 // copies in AddRegisterOperand.
155 const TargetRegisterClass *SrcRC = nullptr, *DstRC = nullptr;
156 SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT);
158 // Figure out the register class to create for the destreg.
160 DstRC = MRI->getRegClass(VRBase);
162 assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!");
165 DstRC = TLI->getRegClassFor(VT);
168 // If all uses are reading from the src physical register and copying the
169 // register is either impossible or very expensive, then don't create a copy.
170 if (MatchReg && SrcRC->getCopyCost() < 0) {
173 // Create the reg, emit the copy.
174 VRBase = MRI->createVirtualRegister(DstRC);
175 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
176 VRBase).addReg(SrcReg);
179 SDValue Op(Node, ResNo);
182 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
183 (void)isNew; // Silence compiler warning.
184 assert(isNew && "Node emitted out of order - early");
187 /// getDstOfCopyToRegUse - If the only use of the specified result number of
188 /// node is a CopyToReg, return its destination register. Return 0 otherwise.
189 unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node,
190 unsigned ResNo) const {
191 if (!Node->hasOneUse())
194 SDNode *User = *Node->use_begin();
195 if (User->getOpcode() == ISD::CopyToReg &&
196 User->getOperand(2).getNode() == Node &&
197 User->getOperand(2).getResNo() == ResNo) {
198 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
199 if (TargetRegisterInfo::isVirtualRegister(Reg))
205 void InstrEmitter::CreateVirtualRegisters(SDNode *Node,
206 MachineInstrBuilder &MIB,
207 const MCInstrDesc &II,
208 bool IsClone, bool IsCloned,
209 DenseMap<SDValue, unsigned> &VRBaseMap) {
210 assert(Node->getMachineOpcode() != TargetOpcode::IMPLICIT_DEF &&
211 "IMPLICIT_DEF should have been handled as a special case elsewhere!");
213 unsigned NumResults = CountResults(Node);
214 for (unsigned i = 0; i < II.getNumDefs(); ++i) {
215 // If the specific node value is only used by a CopyToReg and the dest reg
216 // is a vreg in the same register class, use the CopyToReg'd destination
217 // register instead of creating a new vreg.
219 const TargetRegisterClass *RC =
220 TRI->getAllocatableClass(TII->getRegClass(II, i, TRI, *MF));
221 // Always let the value type influence the used register class. The
222 // constraints on the instruction may be too lax to represent the value
223 // type correctly. For example, a 64-bit float (X86::FR64) can't live in
224 // the 32-bit float super-class (X86::FR32).
225 if (i < NumResults && TLI->isTypeLegal(Node->getSimpleValueType(i))) {
226 const TargetRegisterClass *VTRC =
227 TLI->getRegClassFor(Node->getSimpleValueType(i));
229 VTRC = TRI->getCommonSubClass(RC, VTRC);
234 if (II.OpInfo[i].isOptionalDef()) {
235 // Optional def must be a physical register.
236 unsigned NumResults = CountResults(Node);
237 VRBase = cast<RegisterSDNode>(Node->getOperand(i-NumResults))->getReg();
238 assert(TargetRegisterInfo::isPhysicalRegister(VRBase));
239 MIB.addReg(VRBase, RegState::Define);
242 if (!VRBase && !IsClone && !IsCloned)
243 for (SDNode *User : Node->uses()) {
244 if (User->getOpcode() == ISD::CopyToReg &&
245 User->getOperand(2).getNode() == Node &&
246 User->getOperand(2).getResNo() == i) {
247 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
248 if (TargetRegisterInfo::isVirtualRegister(Reg)) {
249 const TargetRegisterClass *RegRC = MRI->getRegClass(Reg);
252 MIB.addReg(VRBase, RegState::Define);
259 // Create the result registers for this node and add the result regs to
260 // the machine instruction.
262 assert(RC && "Isn't a register operand!");
263 VRBase = MRI->createVirtualRegister(RC);
264 MIB.addReg(VRBase, RegState::Define);
270 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
271 (void)isNew; // Silence compiler warning.
272 assert(isNew && "Node emitted out of order - early");
276 /// getVR - Return the virtual register corresponding to the specified result
277 /// of the specified node.
278 unsigned InstrEmitter::getVR(SDValue Op,
279 DenseMap<SDValue, unsigned> &VRBaseMap) {
280 if (Op.isMachineOpcode() &&
281 Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) {
282 // Add an IMPLICIT_DEF instruction before every use.
283 unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo());
284 // IMPLICIT_DEF can produce any type of result so its MCInstrDesc
285 // does not include operand register class info.
287 const TargetRegisterClass *RC =
288 TLI->getRegClassFor(Op.getSimpleValueType());
289 VReg = MRI->createVirtualRegister(RC);
291 BuildMI(*MBB, InsertPos, Op.getDebugLoc(),
292 TII->get(TargetOpcode::IMPLICIT_DEF), VReg);
296 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op);
297 assert(I != VRBaseMap.end() && "Node emitted out of order - late");
302 /// AddRegisterOperand - Add the specified register as an operand to the
303 /// specified machine instr. Insert register copies if the register is
304 /// not in the required register class.
306 InstrEmitter::AddRegisterOperand(MachineInstrBuilder &MIB,
309 const MCInstrDesc *II,
310 DenseMap<SDValue, unsigned> &VRBaseMap,
311 bool IsDebug, bool IsClone, bool IsCloned) {
312 assert(Op.getValueType() != MVT::Other &&
313 Op.getValueType() != MVT::Glue &&
314 "Chain and glue operands should occur at end of operand list!");
315 // Get/emit the operand.
316 unsigned VReg = getVR(Op, VRBaseMap);
317 assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
319 const MCInstrDesc &MCID = MIB->getDesc();
320 bool isOptDef = IIOpNum < MCID.getNumOperands() &&
321 MCID.OpInfo[IIOpNum].isOptionalDef();
323 // If the instruction requires a register in a different class, create
324 // a new virtual register and copy the value into it, but first attempt to
325 // shrink VReg's register class within reason. For example, if VReg == GR32
326 // and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP.
328 const TargetRegisterClass *DstRC = nullptr;
329 if (IIOpNum < II->getNumOperands())
330 DstRC = TRI->getAllocatableClass(TII->getRegClass(*II,IIOpNum,TRI,*MF));
331 if (DstRC && !MRI->constrainRegClass(VReg, DstRC, MinRCSize)) {
332 unsigned NewVReg = MRI->createVirtualRegister(DstRC);
333 BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(),
334 TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg);
339 // If this value has only one use, that use is a kill. This is a
340 // conservative approximation. InstrEmitter does trivial coalescing
341 // with CopyFromReg nodes, so don't emit kill flags for them.
342 // Avoid kill flags on Schedule cloned nodes, since there will be
344 // Tied operands are never killed, so we need to check that. And that
345 // means we need to determine the index of the operand.
346 bool isKill = Op.hasOneUse() &&
347 Op.getNode()->getOpcode() != ISD::CopyFromReg &&
349 !(IsClone || IsCloned);
351 unsigned Idx = MIB->getNumOperands();
353 MIB->getOperand(Idx-1).isReg() &&
354 MIB->getOperand(Idx-1).isImplicit())
356 bool isTied = MCID.getOperandConstraint(Idx, MCOI::TIED_TO) != -1;
361 MIB.addReg(VReg, getDefRegState(isOptDef) | getKillRegState(isKill) |
362 getDebugRegState(IsDebug));
365 /// AddOperand - Add the specified operand to the specified machine instr. II
366 /// specifies the instruction information for the node, and IIOpNum is the
367 /// operand number (in the II) that we are adding.
368 void InstrEmitter::AddOperand(MachineInstrBuilder &MIB,
371 const MCInstrDesc *II,
372 DenseMap<SDValue, unsigned> &VRBaseMap,
373 bool IsDebug, bool IsClone, bool IsCloned) {
374 if (Op.isMachineOpcode()) {
375 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
376 IsDebug, IsClone, IsCloned);
377 } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
378 MIB.addImm(C->getSExtValue());
379 } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
380 MIB.addFPImm(F->getConstantFPValue());
381 } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
382 // Turn additional physreg operands into implicit uses on non-variadic
383 // instructions. This is used by call and return instructions passing
384 // arguments in registers.
385 bool Imp = II && (IIOpNum >= II->getNumOperands() && !II->isVariadic());
386 MIB.addReg(R->getReg(), getImplRegState(Imp));
387 } else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) {
388 MIB.addRegMask(RM->getRegMask());
389 } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
390 MIB.addGlobalAddress(TGA->getGlobal(), TGA->getOffset(),
391 TGA->getTargetFlags());
392 } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) {
393 MIB.addMBB(BBNode->getBasicBlock());
394 } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) {
395 MIB.addFrameIndex(FI->getIndex());
396 } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) {
397 MIB.addJumpTableIndex(JT->getIndex(), JT->getTargetFlags());
398 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
399 int Offset = CP->getOffset();
400 unsigned Align = CP->getAlignment();
401 Type *Type = CP->getType();
402 // MachineConstantPool wants an explicit alignment.
404 Align = TM->getDataLayout()->getPrefTypeAlignment(Type);
406 // Alignment of vector types. FIXME!
407 Align = TM->getDataLayout()->getTypeAllocSize(Type);
412 MachineConstantPool *MCP = MF->getConstantPool();
413 if (CP->isMachineConstantPoolEntry())
414 Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align);
416 Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align);
417 MIB.addConstantPoolIndex(Idx, Offset, CP->getTargetFlags());
418 } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
419 MIB.addExternalSymbol(ES->getSymbol(), ES->getTargetFlags());
420 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) {
421 MIB.addBlockAddress(BA->getBlockAddress(),
423 BA->getTargetFlags());
424 } else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) {
425 MIB.addTargetIndex(TI->getIndex(), TI->getOffset(), TI->getTargetFlags());
427 assert(Op.getValueType() != MVT::Other &&
428 Op.getValueType() != MVT::Glue &&
429 "Chain and glue operands should occur at end of operand list!");
430 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
431 IsDebug, IsClone, IsCloned);
435 unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx,
436 MVT VT, DebugLoc DL) {
437 const TargetRegisterClass *VRC = MRI->getRegClass(VReg);
438 const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx);
440 // RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg
443 RC = MRI->constrainRegClass(VReg, RC, MinRCSize);
445 // VReg has been adjusted. It can be used with SubIdx operands now.
449 // VReg couldn't be reasonably constrained. Emit a COPY to a new virtual
451 RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx);
452 assert(RC && "No legal register class for VT supports that SubIdx");
453 unsigned NewReg = MRI->createVirtualRegister(RC);
454 BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg)
459 /// EmitSubregNode - Generate machine code for subreg nodes.
461 void InstrEmitter::EmitSubregNode(SDNode *Node,
462 DenseMap<SDValue, unsigned> &VRBaseMap,
463 bool IsClone, bool IsCloned) {
465 unsigned Opc = Node->getMachineOpcode();
467 // If the node is only used by a CopyToReg and the dest reg is a vreg, use
468 // the CopyToReg'd destination register instead of creating a new vreg.
469 for (SDNode *User : Node->uses()) {
470 if (User->getOpcode() == ISD::CopyToReg &&
471 User->getOperand(2).getNode() == Node) {
472 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
473 if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
480 if (Opc == TargetOpcode::EXTRACT_SUBREG) {
481 // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no
482 // constraints on the %dst register, COPY can target all legal register
484 unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
485 const TargetRegisterClass *TRC =
486 TLI->getRegClassFor(Node->getSimpleValueType(0));
488 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
489 MachineInstr *DefMI = MRI->getVRegDef(VReg);
490 unsigned SrcReg, DstReg, DefSubIdx;
492 TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) &&
493 SubIdx == DefSubIdx &&
494 TRC == MRI->getRegClass(SrcReg)) {
496 // r1025 = s/zext r1024, 4
497 // r1026 = extract_subreg r1025, 4
499 // r1026 = copy r1024
500 VRBase = MRI->createVirtualRegister(TRC);
501 BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
502 TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg);
503 MRI->clearKillFlags(SrcReg);
505 // VReg may not support a SubIdx sub-register, and we may need to
506 // constrain its register class or issue a COPY to a compatible register
508 VReg = ConstrainForSubReg(VReg, SubIdx,
509 Node->getOperand(0).getSimpleValueType(),
510 Node->getDebugLoc());
512 // Create the destreg if it is missing.
514 VRBase = MRI->createVirtualRegister(TRC);
516 // Create the extract_subreg machine instruction.
517 BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
518 TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx);
520 } else if (Opc == TargetOpcode::INSERT_SUBREG ||
521 Opc == TargetOpcode::SUBREG_TO_REG) {
522 SDValue N0 = Node->getOperand(0);
523 SDValue N1 = Node->getOperand(1);
524 SDValue N2 = Node->getOperand(2);
525 unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue();
527 // Figure out the register class to create for the destreg. It should be
528 // the largest legal register class supporting SubIdx sub-registers.
529 // RegisterCoalescer will constrain it further if it decides to eliminate
530 // the INSERT_SUBREG instruction.
532 // %dst = INSERT_SUBREG %src, %sub, SubIdx
534 // is lowered by TwoAddressInstructionPass to:
537 // %dst:SubIdx = COPY %sub
539 // There is no constraint on the %src register class.
541 const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getSimpleValueType(0));
542 SRC = TRI->getSubClassWithSubReg(SRC, SubIdx);
543 assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG");
545 if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase)))
546 VRBase = MRI->createVirtualRegister(SRC);
548 // Create the insert_subreg or subreg_to_reg machine instruction.
549 MachineInstrBuilder MIB =
550 BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc), VRBase);
552 // If creating a subreg_to_reg, then the first input operand
553 // is an implicit value immediate, otherwise it's a register
554 if (Opc == TargetOpcode::SUBREG_TO_REG) {
555 const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
556 MIB.addImm(SD->getZExtValue());
558 AddOperand(MIB, N0, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
560 // Add the subregster being inserted
561 AddOperand(MIB, N1, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
564 MBB->insert(InsertPos, MIB);
566 llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg");
569 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
570 (void)isNew; // Silence compiler warning.
571 assert(isNew && "Node emitted out of order - early");
574 /// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes.
575 /// COPY_TO_REGCLASS is just a normal copy, except that the destination
576 /// register is constrained to be in a particular register class.
579 InstrEmitter::EmitCopyToRegClassNode(SDNode *Node,
580 DenseMap<SDValue, unsigned> &VRBaseMap) {
581 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
583 // Create the new VReg in the destination class and emit a copy.
584 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
585 const TargetRegisterClass *DstRC =
586 TRI->getAllocatableClass(TRI->getRegClass(DstRCIdx));
587 unsigned NewVReg = MRI->createVirtualRegister(DstRC);
588 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
589 NewVReg).addReg(VReg);
592 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
593 (void)isNew; // Silence compiler warning.
594 assert(isNew && "Node emitted out of order - early");
597 /// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes.
599 void InstrEmitter::EmitRegSequence(SDNode *Node,
600 DenseMap<SDValue, unsigned> &VRBaseMap,
601 bool IsClone, bool IsCloned) {
602 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue();
603 const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx);
604 unsigned NewVReg = MRI->createVirtualRegister(TRI->getAllocatableClass(RC));
605 const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE);
606 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II, NewVReg);
607 unsigned NumOps = Node->getNumOperands();
608 assert((NumOps & 1) == 1 &&
609 "REG_SEQUENCE must have an odd number of operands!");
610 for (unsigned i = 1; i != NumOps; ++i) {
611 SDValue Op = Node->getOperand(i);
613 RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1));
614 // Skip physical registers as they don't have a vreg to get and we'll
615 // insert copies for them in TwoAddressInstructionPass anyway.
616 if (!R || !TargetRegisterInfo::isPhysicalRegister(R->getReg())) {
617 unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue();
618 unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap);
619 const TargetRegisterClass *TRC = MRI->getRegClass(SubReg);
620 const TargetRegisterClass *SRC =
621 TRI->getMatchingSuperRegClass(RC, TRC, SubIdx);
622 if (SRC && SRC != RC) {
623 MRI->setRegClass(NewVReg, SRC);
628 AddOperand(MIB, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false,
632 MBB->insert(InsertPos, MIB);
634 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
635 (void)isNew; // Silence compiler warning.
636 assert(isNew && "Node emitted out of order - early");
639 /// EmitDbgValue - Generate machine instruction for a dbg_value node.
642 InstrEmitter::EmitDbgValue(SDDbgValue *SD,
643 DenseMap<SDValue, unsigned> &VRBaseMap) {
644 uint64_t Offset = SD->getOffset();
645 MDNode* MDPtr = SD->getMDPtr();
646 DebugLoc DL = SD->getDebugLoc();
648 if (SD->getKind() == SDDbgValue::FRAMEIX) {
649 // Stack address; this needs to be lowered in target-dependent fashion.
650 // EmitTargetCodeForFrameDebugValue is responsible for allocation.
651 return BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE))
652 .addFrameIndex(SD->getFrameIx()).addImm(Offset).addMetadata(MDPtr);
654 // Otherwise, we're going to create an instruction here.
655 const MCInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE);
656 MachineInstrBuilder MIB = BuildMI(*MF, DL, II);
657 if (SD->getKind() == SDDbgValue::SDNODE) {
658 SDNode *Node = SD->getSDNode();
659 SDValue Op = SDValue(Node, SD->getResNo());
660 // It's possible we replaced this SDNode with other(s) and therefore
661 // didn't generate code for it. It's better to catch these cases where
662 // they happen and transfer the debug info, but trying to guarantee that
663 // in all cases would be very fragile; this is a safeguard for any
665 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op);
666 if (I==VRBaseMap.end())
667 MIB.addReg(0U); // undef
669 AddOperand(MIB, Op, (*MIB).getNumOperands(), &II, VRBaseMap,
670 /*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false);
671 } else if (SD->getKind() == SDDbgValue::CONST) {
672 const Value *V = SD->getConst();
673 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
674 if (CI->getBitWidth() > 64)
677 MIB.addImm(CI->getSExtValue());
678 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
681 // Could be an Undef. In any case insert an Undef so we can see what we
686 // Insert an Undef so we can see what we dropped.
690 if (Offset != 0) // Indirect addressing.
693 MIB.addReg(0U, RegState::Debug);
695 MIB.addMetadata(MDPtr);
700 /// EmitMachineNode - Generate machine code for a target-specific node and
701 /// needed dependencies.
704 EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned,
705 DenseMap<SDValue, unsigned> &VRBaseMap) {
706 unsigned Opc = Node->getMachineOpcode();
708 // Handle subreg insert/extract specially
709 if (Opc == TargetOpcode::EXTRACT_SUBREG ||
710 Opc == TargetOpcode::INSERT_SUBREG ||
711 Opc == TargetOpcode::SUBREG_TO_REG) {
712 EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned);
716 // Handle COPY_TO_REGCLASS specially.
717 if (Opc == TargetOpcode::COPY_TO_REGCLASS) {
718 EmitCopyToRegClassNode(Node, VRBaseMap);
722 // Handle REG_SEQUENCE specially.
723 if (Opc == TargetOpcode::REG_SEQUENCE) {
724 EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned);
728 if (Opc == TargetOpcode::IMPLICIT_DEF)
729 // We want a unique VR for each IMPLICIT_DEF use.
732 const MCInstrDesc &II = TII->get(Opc);
733 unsigned NumResults = CountResults(Node);
734 unsigned NumDefs = II.getNumDefs();
735 const MCPhysReg *ScratchRegs = nullptr;
737 // Handle STACKMAP and PATCHPOINT specially and then use the generic code.
738 if (Opc == TargetOpcode::STACKMAP || Opc == TargetOpcode::PATCHPOINT) {
739 // Stackmaps do not have arguments and do not preserve their calling
740 // convention. However, to simplify runtime support, they clobber the same
741 // scratch registers as AnyRegCC.
742 unsigned CC = CallingConv::AnyReg;
743 if (Opc == TargetOpcode::PATCHPOINT) {
744 CC = Node->getConstantOperandVal(PatchPointOpers::CCPos);
745 NumDefs = NumResults;
747 ScratchRegs = TLI->getScratchRegisters((CallingConv::ID) CC);
750 unsigned NumImpUses = 0;
751 unsigned NodeOperands =
752 countOperands(Node, II.getNumOperands() - NumDefs, NumImpUses);
753 bool HasPhysRegOuts = NumResults > NumDefs && II.getImplicitDefs()!=nullptr;
755 unsigned NumMIOperands = NodeOperands + NumResults;
757 assert(NumMIOperands >= II.getNumOperands() &&
758 "Too few operands for a variadic node!");
760 assert(NumMIOperands >= II.getNumOperands() &&
761 NumMIOperands <= II.getNumOperands() + II.getNumImplicitDefs() +
763 "#operands for dag node doesn't match .td file!");
766 // Create the new machine instruction.
767 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II);
769 // Add result register values for things that are defined by this
772 CreateVirtualRegisters(Node, MIB, II, IsClone, IsCloned, VRBaseMap);
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);
784 // Add scratch registers as implicit def and early clobber
786 for (unsigned i = 0; ScratchRegs[i]; ++i)
787 MIB.addReg(ScratchRegs[i], RegState::ImplicitDefine |
788 RegState::EarlyClobber);
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());
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);
799 // The MachineInstr may also define physregs instead of virtregs. These
800 // physreg values can reach other instructions in different ways:
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.
806 // 2. A CopyFromReg reading a physreg may be glued to this instruction.
808 // 3. A glued instruction may implicitly use a physreg.
810 // 4. A glued instruction may use a RegisterSDNode operand.
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;
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))
822 // This implicitly defined physreg has a use.
823 UsedRegs.push_back(Reg);
824 EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap);
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());
834 } else if (F->getOpcode() == ISD::CopyToReg) {
835 // Skip CopyToReg nodes that are internal to the glue chain.
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);
853 // Finally mark unused registers as dead.
854 if (!UsedRegs.empty() || II.getImplicitDefs())
855 MIB->setPhysRegsDeadExcept(UsedRegs, *TRI);
857 // Run post-isel target hook to adjust this instruction if needed.
859 if (II.hasPostISelHook())
861 TLI->AdjustInstrPostInstrSelection(MIB, Node);
864 /// EmitSpecialNode - Generate machine code for a target-independent node and
865 /// needed dependencies.
867 EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned,
868 DenseMap<SDValue, unsigned> &VRBaseMap) {
869 switch (Node->getOpcode()) {
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
880 case ISD::CopyToReg: {
882 SDValue SrcVal = Node->getOperand(2);
883 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal))
884 SrcReg = R->getReg();
886 SrcReg = getVR(SrcVal, VRBaseMap);
888 unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
889 if (SrcReg == DestReg) // Coalesced away the copy? Ignore.
892 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
893 DestReg).addReg(SrcReg);
896 case ISD::CopyFromReg: {
897 unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
898 EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap);
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);
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;
913 FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Node->getOperand(1));
914 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp))
915 .addFrameIndex(FI->getIndex());
919 case ISD::INLINEASM: {
920 unsigned NumOps = Node->getNumOperands();
921 if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue)
922 --NumOps; // Ignore the glue operand.
924 // Create the inline asm machine instruction.
925 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(),
926 TII->get(TargetOpcode::INLINEASM));
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);
933 // Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore
936 cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))->
938 MIB.addImm(ExtraInfo);
940 // Remember to operand index of the group flags.
941 SmallVector<unsigned, 8> GroupIdx;
943 // Add all of the operand registers to the instruction.
944 for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) {
946 cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
947 const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
949 GroupIdx.push_back(MIB->getNumOperands());
951 ++i; // Skip the ID value.
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)));
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)));
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, nullptr, VRBaseMap,
980 /*IsDebug=*/false, IsClone, IsCloned);
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);
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();
1000 MIB.addMetadata(MD);
1002 MBB->insert(InsertPos, MIB);
1008 /// InstrEmitter - Construct an InstrEmitter and set it to start inserting
1009 /// at the given position in the given block.
1010 InstrEmitter::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) {