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 #include "InstrEmitter.h"
17 #include "SDNodeDbgValue.h"
18 #include "llvm/ADT/Statistic.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/CodeGen/StackMaps.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/DebugInfo.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/TargetSubtargetInfo.h"
34 #define DEBUG_TYPE "instr-emitter"
36 /// MinRCSize - Smallest register class we allow when constraining virtual
37 /// registers. If satisfying all register class constraints would require
38 /// using a smaller register class, emit a COPY to a new virtual register
40 const unsigned MinRCSize = 4;
42 /// CountResults - The results of target nodes have register or immediate
43 /// operands first, then an optional chain, and optional glue operands (which do
44 /// not go into the resulting MachineInstr).
45 unsigned InstrEmitter::CountResults(SDNode *Node) {
46 unsigned N = Node->getNumValues();
47 while (N && Node->getValueType(N - 1) == MVT::Glue)
49 if (N && Node->getValueType(N - 1) == MVT::Other)
50 --N; // Skip over chain result.
54 /// countOperands - The inputs to target nodes have any actual inputs first,
55 /// followed by an optional chain operand, then an optional glue operand.
56 /// Compute the number of actual operands that will go into the resulting
59 /// Also count physreg RegisterSDNode and RegisterMaskSDNode operands preceding
60 /// the chain and glue. These operands may be implicit on the machine instr.
61 static unsigned countOperands(SDNode *Node, unsigned NumExpUses,
62 unsigned &NumImpUses) {
63 unsigned N = Node->getNumOperands();
64 while (N && Node->getOperand(N - 1).getValueType() == MVT::Glue)
66 if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
67 --N; // Ignore chain if it exists.
69 // Count RegisterSDNode and RegisterMaskSDNode operands for NumImpUses.
70 NumImpUses = N - NumExpUses;
71 for (unsigned I = N; I > NumExpUses; --I) {
72 if (isa<RegisterMaskSDNode>(Node->getOperand(I - 1)))
74 if (RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Node->getOperand(I - 1)))
75 if (TargetRegisterInfo::isPhysicalRegister(RN->getReg()))
84 /// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
85 /// implicit physical register output.
87 EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
88 unsigned SrcReg, DenseMap<SDValue, unsigned> &VRBaseMap) {
90 if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
91 // Just use the input register directly!
92 SDValue Op(Node, ResNo);
95 bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second;
96 (void)isNew; // Silence compiler warning.
97 assert(isNew && "Node emitted out of order - early");
101 // If the node is only used by a CopyToReg and the dest reg is a vreg, use
102 // the CopyToReg'd destination register instead of creating a new vreg.
103 bool MatchReg = true;
104 const TargetRegisterClass *UseRC = nullptr;
105 MVT VT = Node->getSimpleValueType(ResNo);
107 // Stick to the preferred register classes for legal types.
108 if (TLI->isTypeLegal(VT))
109 UseRC = TLI->getRegClassFor(VT);
111 if (!IsClone && !IsCloned)
112 for (SDNode *User : Node->uses()) {
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)) {
121 } else if (DestReg != SrcReg)
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)
128 MVT VT = Node->getSimpleValueType(Op.getResNo());
129 if (VT == MVT::Other || VT == MVT::Glue)
132 if (User->isMachineOpcode()) {
133 const MCInstrDesc &II = TII->get(User->getMachineOpcode());
134 const TargetRegisterClass *RC = nullptr;
135 if (i+II.getNumDefs() < II.getNumOperands()) {
136 RC = TRI->getAllocatableClass(
137 TII->getRegClass(II, i+II.getNumDefs(), TRI, *MF));
142 const TargetRegisterClass *ComRC =
143 TRI->getCommonSubClass(UseRC, RC, VT.SimpleTy);
144 // If multiple uses expect disjoint register classes, we emit
145 // copies in AddRegisterOperand.
157 const TargetRegisterClass *SrcRC = nullptr, *DstRC = nullptr;
158 SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT);
160 // Figure out the register class to create for the destreg.
162 DstRC = MRI->getRegClass(VRBase);
164 assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!");
167 DstRC = TLI->getRegClassFor(VT);
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) {
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);
181 SDValue Op(Node, ResNo);
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");
189 /// getDstOfCopyToRegUse - If the only use of the specified result number of
190 /// node is a CopyToReg, return its destination register. Return 0 otherwise.
191 unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node,
192 unsigned ResNo) const {
193 if (!Node->hasOneUse())
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))
207 void 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!");
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.
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));
231 VTRC = TRI->getCommonSubClass(RC, VTRC);
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);
244 if (!VRBase && !IsClone && !IsCloned)
245 for (SDNode *User : Node->uses()) {
246 if (User->getOpcode() == ISD::CopyToReg &&
247 User->getOperand(2).getNode() == Node &&
248 User->getOperand(2).getResNo() == i) {
249 unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
250 if (TargetRegisterInfo::isVirtualRegister(Reg)) {
251 const TargetRegisterClass *RegRC = MRI->getRegClass(Reg);
254 MIB.addReg(VRBase, RegState::Define);
261 // Create the result registers for this node and add the result regs to
262 // the machine instruction.
264 assert(RC && "Isn't a register operand!");
265 VRBase = MRI->createVirtualRegister(RC);
266 MIB.addReg(VRBase, RegState::Define);
269 // If this def corresponds to a result of the SDNode insert the VRBase into
271 if (i < NumResults) {
275 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
276 (void)isNew; // Silence compiler warning.
277 assert(isNew && "Node emitted out of order - early");
282 /// getVR - Return the virtual register corresponding to the specified result
283 /// of the specified node.
284 unsigned InstrEmitter::getVR(SDValue Op,
285 DenseMap<SDValue, unsigned> &VRBaseMap) {
286 if (Op.isMachineOpcode() &&
287 Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) {
288 // Add an IMPLICIT_DEF instruction before every use.
289 unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo());
290 // IMPLICIT_DEF can produce any type of result so its MCInstrDesc
291 // does not include operand register class info.
293 const TargetRegisterClass *RC =
294 TLI->getRegClassFor(Op.getSimpleValueType());
295 VReg = MRI->createVirtualRegister(RC);
297 BuildMI(*MBB, InsertPos, Op.getDebugLoc(),
298 TII->get(TargetOpcode::IMPLICIT_DEF), VReg);
302 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op);
303 assert(I != VRBaseMap.end() && "Node emitted out of order - late");
308 /// AddRegisterOperand - Add the specified register as an operand to the
309 /// specified machine instr. Insert register copies if the register is
310 /// not in the required register class.
312 InstrEmitter::AddRegisterOperand(MachineInstrBuilder &MIB,
315 const MCInstrDesc *II,
316 DenseMap<SDValue, unsigned> &VRBaseMap,
317 bool IsDebug, bool IsClone, bool IsCloned) {
318 assert(Op.getValueType() != MVT::Other &&
319 Op.getValueType() != MVT::Glue &&
320 "Chain and glue operands should occur at end of operand list!");
321 // Get/emit the operand.
322 unsigned VReg = getVR(Op, VRBaseMap);
324 const MCInstrDesc &MCID = MIB->getDesc();
325 bool isOptDef = IIOpNum < MCID.getNumOperands() &&
326 MCID.OpInfo[IIOpNum].isOptionalDef();
328 // If the instruction requires a register in a different class, create
329 // a new virtual register and copy the value into it, but first attempt to
330 // shrink VReg's register class within reason. For example, if VReg == GR32
331 // and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP.
333 const TargetRegisterClass *DstRC = nullptr;
334 if (IIOpNum < II->getNumOperands())
335 DstRC = TRI->getAllocatableClass(TII->getRegClass(*II,IIOpNum,TRI,*MF));
336 assert((!DstRC || TargetRegisterInfo::isVirtualRegister(VReg)) &&
338 if (DstRC && !MRI->constrainRegClass(VReg, DstRC, MinRCSize)) {
339 unsigned NewVReg = MRI->createVirtualRegister(DstRC);
340 BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(),
341 TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg);
346 // If this value has only one use, that use is a kill. This is a
347 // conservative approximation. InstrEmitter does trivial coalescing
348 // with CopyFromReg nodes, so don't emit kill flags for them.
349 // Avoid kill flags on Schedule cloned nodes, since there will be
351 // Tied operands are never killed, so we need to check that. And that
352 // means we need to determine the index of the operand.
353 bool isKill = Op.hasOneUse() &&
354 Op.getNode()->getOpcode() != ISD::CopyFromReg &&
356 !(IsClone || IsCloned);
358 unsigned Idx = MIB->getNumOperands();
360 MIB->getOperand(Idx-1).isReg() &&
361 MIB->getOperand(Idx-1).isImplicit())
363 bool isTied = MCID.getOperandConstraint(Idx, MCOI::TIED_TO) != -1;
368 MIB.addReg(VReg, getDefRegState(isOptDef) | getKillRegState(isKill) |
369 getDebugRegState(IsDebug));
372 /// AddOperand - Add the specified operand to the specified machine instr. II
373 /// specifies the instruction information for the node, and IIOpNum is the
374 /// operand number (in the II) that we are adding.
375 void InstrEmitter::AddOperand(MachineInstrBuilder &MIB,
378 const MCInstrDesc *II,
379 DenseMap<SDValue, unsigned> &VRBaseMap,
380 bool IsDebug, bool IsClone, bool IsCloned) {
381 if (Op.isMachineOpcode()) {
382 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
383 IsDebug, IsClone, IsCloned);
384 } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
385 MIB.addImm(C->getSExtValue());
386 } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
387 MIB.addFPImm(F->getConstantFPValue());
388 } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
389 // Turn additional physreg operands into implicit uses on non-variadic
390 // instructions. This is used by call and return instructions passing
391 // arguments in registers.
392 bool Imp = II && (IIOpNum >= II->getNumOperands() && !II->isVariadic());
393 MIB.addReg(R->getReg(), getImplRegState(Imp));
394 } else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) {
395 MIB.addRegMask(RM->getRegMask());
396 } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
397 MIB.addGlobalAddress(TGA->getGlobal(), TGA->getOffset(),
398 TGA->getTargetFlags());
399 } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) {
400 MIB.addMBB(BBNode->getBasicBlock());
401 } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) {
402 MIB.addFrameIndex(FI->getIndex());
403 } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) {
404 MIB.addJumpTableIndex(JT->getIndex(), JT->getTargetFlags());
405 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
406 int Offset = CP->getOffset();
407 unsigned Align = CP->getAlignment();
408 Type *Type = CP->getType();
409 // MachineConstantPool wants an explicit alignment.
411 Align = MF->getDataLayout().getPrefTypeAlignment(Type);
413 // Alignment of vector types. FIXME!
414 Align = MF->getDataLayout().getTypeAllocSize(Type);
419 MachineConstantPool *MCP = MF->getConstantPool();
420 if (CP->isMachineConstantPoolEntry())
421 Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align);
423 Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align);
424 MIB.addConstantPoolIndex(Idx, Offset, CP->getTargetFlags());
425 } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
426 MIB.addExternalSymbol(ES->getSymbol(), ES->getTargetFlags());
427 } else if (auto *SymNode = dyn_cast<MCSymbolSDNode>(Op)) {
428 MIB.addSym(SymNode->getMCSymbol());
429 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) {
430 MIB.addBlockAddress(BA->getBlockAddress(),
432 BA->getTargetFlags());
433 } else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) {
434 MIB.addTargetIndex(TI->getIndex(), TI->getOffset(), TI->getTargetFlags());
436 assert(Op.getValueType() != MVT::Other &&
437 Op.getValueType() != MVT::Glue &&
438 "Chain and glue operands should occur at end of operand list!");
439 AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
440 IsDebug, IsClone, IsCloned);
444 unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx,
445 MVT VT, const DebugLoc &DL) {
446 const TargetRegisterClass *VRC = MRI->getRegClass(VReg);
447 const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx);
449 // RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg
452 RC = MRI->constrainRegClass(VReg, RC, MinRCSize);
454 // VReg has been adjusted. It can be used with SubIdx operands now.
458 // VReg couldn't be reasonably constrained. Emit a COPY to a new virtual
460 RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx);
461 assert(RC && "No legal register class for VT supports that SubIdx");
462 unsigned NewReg = MRI->createVirtualRegister(RC);
463 BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg)
468 /// EmitSubregNode - Generate machine code for subreg nodes.
470 void InstrEmitter::EmitSubregNode(SDNode *Node,
471 DenseMap<SDValue, unsigned> &VRBaseMap,
472 bool IsClone, bool IsCloned) {
474 unsigned Opc = Node->getMachineOpcode();
476 // If the node is only used by a CopyToReg and the dest reg is a vreg, use
477 // the CopyToReg'd destination register instead of creating a new vreg.
478 for (SDNode *User : Node->uses()) {
479 if (User->getOpcode() == ISD::CopyToReg &&
480 User->getOperand(2).getNode() == Node) {
481 unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
482 if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
489 if (Opc == TargetOpcode::EXTRACT_SUBREG) {
490 // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no
491 // constraints on the %dst register, COPY can target all legal register
493 unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
494 const TargetRegisterClass *TRC =
495 TLI->getRegClassFor(Node->getSimpleValueType(0));
497 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
498 MachineInstr *DefMI = MRI->getVRegDef(VReg);
499 unsigned SrcReg, DstReg, DefSubIdx;
501 TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) &&
502 SubIdx == DefSubIdx &&
503 TRC == MRI->getRegClass(SrcReg)) {
505 // r1025 = s/zext r1024, 4
506 // r1026 = extract_subreg r1025, 4
508 // r1026 = copy r1024
509 VRBase = MRI->createVirtualRegister(TRC);
510 BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
511 TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg);
512 MRI->clearKillFlags(SrcReg);
514 // VReg may not support a SubIdx sub-register, and we may need to
515 // constrain its register class or issue a COPY to a compatible register
517 VReg = ConstrainForSubReg(VReg, SubIdx,
518 Node->getOperand(0).getSimpleValueType(),
519 Node->getDebugLoc());
521 // Create the destreg if it is missing.
523 VRBase = MRI->createVirtualRegister(TRC);
525 // Create the extract_subreg machine instruction.
526 BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
527 TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx);
529 } else if (Opc == TargetOpcode::INSERT_SUBREG ||
530 Opc == TargetOpcode::SUBREG_TO_REG) {
531 SDValue N0 = Node->getOperand(0);
532 SDValue N1 = Node->getOperand(1);
533 SDValue N2 = Node->getOperand(2);
534 unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue();
536 // Figure out the register class to create for the destreg. It should be
537 // the largest legal register class supporting SubIdx sub-registers.
538 // RegisterCoalescer will constrain it further if it decides to eliminate
539 // the INSERT_SUBREG instruction.
541 // %dst = INSERT_SUBREG %src, %sub, SubIdx
543 // is lowered by TwoAddressInstructionPass to:
546 // %dst:SubIdx = COPY %sub
548 // There is no constraint on the %src register class.
550 const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getSimpleValueType(0));
551 SRC = TRI->getSubClassWithSubReg(SRC, SubIdx);
552 assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG");
554 if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase)))
555 VRBase = MRI->createVirtualRegister(SRC);
557 // Create the insert_subreg or subreg_to_reg machine instruction.
558 MachineInstrBuilder MIB =
559 BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc), VRBase);
561 // If creating a subreg_to_reg, then the first input operand
562 // is an implicit value immediate, otherwise it's a register
563 if (Opc == TargetOpcode::SUBREG_TO_REG) {
564 const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
565 MIB.addImm(SD->getZExtValue());
567 AddOperand(MIB, N0, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
569 // Add the subregster being inserted
570 AddOperand(MIB, N1, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
573 MBB->insert(InsertPos, MIB);
575 llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg");
578 bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
579 (void)isNew; // Silence compiler warning.
580 assert(isNew && "Node emitted out of order - early");
583 /// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes.
584 /// COPY_TO_REGCLASS is just a normal copy, except that the destination
585 /// register is constrained to be in a particular register class.
588 InstrEmitter::EmitCopyToRegClassNode(SDNode *Node,
589 DenseMap<SDValue, unsigned> &VRBaseMap) {
590 unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
592 // Create the new VReg in the destination class and emit a copy.
593 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
594 const TargetRegisterClass *DstRC =
595 TRI->getAllocatableClass(TRI->getRegClass(DstRCIdx));
596 unsigned NewVReg = MRI->createVirtualRegister(DstRC);
597 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
598 NewVReg).addReg(VReg);
601 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
602 (void)isNew; // Silence compiler warning.
603 assert(isNew && "Node emitted out of order - early");
606 /// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes.
608 void InstrEmitter::EmitRegSequence(SDNode *Node,
609 DenseMap<SDValue, unsigned> &VRBaseMap,
610 bool IsClone, bool IsCloned) {
611 unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue();
612 const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx);
613 unsigned NewVReg = MRI->createVirtualRegister(TRI->getAllocatableClass(RC));
614 const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE);
615 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II, NewVReg);
616 unsigned NumOps = Node->getNumOperands();
617 assert((NumOps & 1) == 1 &&
618 "REG_SEQUENCE must have an odd number of operands!");
619 for (unsigned i = 1; i != NumOps; ++i) {
620 SDValue Op = Node->getOperand(i);
622 RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1));
623 // Skip physical registers as they don't have a vreg to get and we'll
624 // insert copies for them in TwoAddressInstructionPass anyway.
625 if (!R || !TargetRegisterInfo::isPhysicalRegister(R->getReg())) {
626 unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue();
627 unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap);
628 const TargetRegisterClass *TRC = MRI->getRegClass(SubReg);
629 const TargetRegisterClass *SRC =
630 TRI->getMatchingSuperRegClass(RC, TRC, SubIdx);
631 if (SRC && SRC != RC) {
632 MRI->setRegClass(NewVReg, SRC);
637 AddOperand(MIB, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false,
641 MBB->insert(InsertPos, MIB);
643 bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
644 (void)isNew; // Silence compiler warning.
645 assert(isNew && "Node emitted out of order - early");
648 /// EmitDbgValue - Generate machine instruction for a dbg_value node.
651 InstrEmitter::EmitDbgValue(SDDbgValue *SD,
652 DenseMap<SDValue, unsigned> &VRBaseMap) {
653 uint64_t Offset = SD->getOffset();
654 MDNode *Var = SD->getVariable();
655 MDNode *Expr = SD->getExpression();
656 DebugLoc DL = SD->getDebugLoc();
657 assert(cast<DILocalVariable>(Var)->isValidLocationForIntrinsic(DL) &&
658 "Expected inlined-at fields to agree");
660 if (SD->getKind() == SDDbgValue::FRAMEIX) {
661 // Stack address; this needs to be lowered in target-dependent fashion.
662 // EmitTargetCodeForFrameDebugValue is responsible for allocation.
663 return BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE))
664 .addFrameIndex(SD->getFrameIx())
669 // Otherwise, we're going to create an instruction here.
670 const MCInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE);
671 MachineInstrBuilder MIB = BuildMI(*MF, DL, II);
672 if (SD->getKind() == SDDbgValue::SDNODE) {
673 SDNode *Node = SD->getSDNode();
674 SDValue Op = SDValue(Node, SD->getResNo());
675 // It's possible we replaced this SDNode with other(s) and therefore
676 // didn't generate code for it. It's better to catch these cases where
677 // they happen and transfer the debug info, but trying to guarantee that
678 // in all cases would be very fragile; this is a safeguard for any
680 DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op);
681 if (I==VRBaseMap.end())
682 MIB.addReg(0U); // undef
684 AddOperand(MIB, Op, (*MIB).getNumOperands(), &II, VRBaseMap,
685 /*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false);
686 } else if (SD->getKind() == SDDbgValue::CONST) {
687 const Value *V = SD->getConst();
688 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
689 if (CI->getBitWidth() > 64)
692 MIB.addImm(CI->getSExtValue());
693 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
696 // Could be an Undef. In any case insert an Undef so we can see what we
701 // Insert an Undef so we can see what we dropped.
705 // Indirect addressing is indicated by an Imm as the second parameter.
706 if (SD->isIndirect())
709 assert(Offset == 0 && "direct value cannot have an offset");
710 MIB.addReg(0U, RegState::Debug);
713 MIB.addMetadata(Var);
714 MIB.addMetadata(Expr);
719 /// EmitMachineNode - Generate machine code for a target-specific node and
720 /// needed dependencies.
723 EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned,
724 DenseMap<SDValue, unsigned> &VRBaseMap) {
725 unsigned Opc = Node->getMachineOpcode();
727 // Handle subreg insert/extract specially
728 if (Opc == TargetOpcode::EXTRACT_SUBREG ||
729 Opc == TargetOpcode::INSERT_SUBREG ||
730 Opc == TargetOpcode::SUBREG_TO_REG) {
731 EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned);
735 // Handle COPY_TO_REGCLASS specially.
736 if (Opc == TargetOpcode::COPY_TO_REGCLASS) {
737 EmitCopyToRegClassNode(Node, VRBaseMap);
741 // Handle REG_SEQUENCE specially.
742 if (Opc == TargetOpcode::REG_SEQUENCE) {
743 EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned);
747 if (Opc == TargetOpcode::IMPLICIT_DEF)
748 // We want a unique VR for each IMPLICIT_DEF use.
751 const MCInstrDesc &II = TII->get(Opc);
752 unsigned NumResults = CountResults(Node);
753 unsigned NumDefs = II.getNumDefs();
754 const MCPhysReg *ScratchRegs = nullptr;
756 // Handle STACKMAP and PATCHPOINT specially and then use the generic code.
757 if (Opc == TargetOpcode::STACKMAP || Opc == TargetOpcode::PATCHPOINT) {
758 // Stackmaps do not have arguments and do not preserve their calling
759 // convention. However, to simplify runtime support, they clobber the same
760 // scratch registers as AnyRegCC.
761 unsigned CC = CallingConv::AnyReg;
762 if (Opc == TargetOpcode::PATCHPOINT) {
763 CC = Node->getConstantOperandVal(PatchPointOpers::CCPos);
764 NumDefs = NumResults;
766 ScratchRegs = TLI->getScratchRegisters((CallingConv::ID) CC);
769 unsigned NumImpUses = 0;
770 unsigned NodeOperands =
771 countOperands(Node, II.getNumOperands() - NumDefs, NumImpUses);
772 bool HasPhysRegOuts = NumResults > NumDefs && II.getImplicitDefs()!=nullptr;
774 unsigned NumMIOperands = NodeOperands + NumResults;
776 assert(NumMIOperands >= II.getNumOperands() &&
777 "Too few operands for a variadic node!");
779 assert(NumMIOperands >= II.getNumOperands() &&
780 NumMIOperands <= II.getNumOperands() + II.getNumImplicitDefs() +
782 "#operands for dag node doesn't match .td file!");
785 // Create the new machine instruction.
786 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II);
788 // Add result register values for things that are defined by this
791 CreateVirtualRegisters(Node, MIB, II, IsClone, IsCloned, VRBaseMap);
793 // Emit all of the actual operands of this instruction, adding them to the
794 // instruction as appropriate.
795 bool HasOptPRefs = NumDefs > NumResults;
796 assert((!HasOptPRefs || !HasPhysRegOuts) &&
797 "Unable to cope with optional defs and phys regs defs!");
798 unsigned NumSkip = HasOptPRefs ? NumDefs - NumResults : 0;
799 for (unsigned i = NumSkip; i != NodeOperands; ++i)
800 AddOperand(MIB, Node->getOperand(i), i-NumSkip+NumDefs, &II,
801 VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned);
803 // Add scratch registers as implicit def and early clobber
805 for (unsigned i = 0; ScratchRegs[i]; ++i)
806 MIB.addReg(ScratchRegs[i], RegState::ImplicitDefine |
807 RegState::EarlyClobber);
809 // Transfer all of the memory reference descriptions of this instruction.
810 MIB.setMemRefs(cast<MachineSDNode>(Node)->memoperands_begin(),
811 cast<MachineSDNode>(Node)->memoperands_end());
813 // Insert the instruction into position in the block. This needs to
814 // happen before any custom inserter hook is called so that the
815 // hook knows where in the block to insert the replacement code.
816 MBB->insert(InsertPos, MIB);
818 // The MachineInstr may also define physregs instead of virtregs. These
819 // physreg values can reach other instructions in different ways:
821 // 1. When there is a use of a Node value beyond the explicitly defined
822 // virtual registers, we emit a CopyFromReg for one of the implicitly
823 // defined physregs. This only happens when HasPhysRegOuts is true.
825 // 2. A CopyFromReg reading a physreg may be glued to this instruction.
827 // 3. A glued instruction may implicitly use a physreg.
829 // 4. A glued instruction may use a RegisterSDNode operand.
831 // Collect all the used physreg defs, and make sure that any unused physreg
832 // defs are marked as dead.
833 SmallVector<unsigned, 8> UsedRegs;
835 // Additional results must be physical register defs.
836 if (HasPhysRegOuts) {
837 for (unsigned i = NumDefs; i < NumResults; ++i) {
838 unsigned Reg = II.getImplicitDefs()[i - NumDefs];
839 if (!Node->hasAnyUseOfValue(i))
841 // This implicitly defined physreg has a use.
842 UsedRegs.push_back(Reg);
843 EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap);
847 // Scan the glue chain for any used physregs.
848 if (Node->getValueType(Node->getNumValues()-1) == MVT::Glue) {
849 for (SDNode *F = Node->getGluedUser(); F; F = F->getGluedUser()) {
850 if (F->getOpcode() == ISD::CopyFromReg) {
851 UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg());
853 } else if (F->getOpcode() == ISD::CopyToReg) {
854 // Skip CopyToReg nodes that are internal to the glue chain.
857 // Collect declared implicit uses.
858 const MCInstrDesc &MCID = TII->get(F->getMachineOpcode());
859 UsedRegs.append(MCID.getImplicitUses(),
860 MCID.getImplicitUses() + MCID.getNumImplicitUses());
861 // In addition to declared implicit uses, we must also check for
862 // direct RegisterSDNode operands.
863 for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i)
864 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) {
865 unsigned Reg = R->getReg();
866 if (TargetRegisterInfo::isPhysicalRegister(Reg))
867 UsedRegs.push_back(Reg);
872 // Finally mark unused registers as dead.
873 if (!UsedRegs.empty() || II.getImplicitDefs())
874 MIB->setPhysRegsDeadExcept(UsedRegs, *TRI);
876 // Run post-isel target hook to adjust this instruction if needed.
877 if (II.hasPostISelHook())
878 TLI->AdjustInstrPostInstrSelection(*MIB, Node);
881 /// EmitSpecialNode - Generate machine code for a target-independent node and
882 /// needed dependencies.
884 EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned,
885 DenseMap<SDValue, unsigned> &VRBaseMap) {
886 switch (Node->getOpcode()) {
891 llvm_unreachable("This target-independent node should have been selected!");
892 case ISD::EntryToken:
893 llvm_unreachable("EntryToken should have been excluded from the schedule!");
894 case ISD::MERGE_VALUES:
895 case ISD::TokenFactor: // fall thru
897 case ISD::CopyToReg: {
899 SDValue SrcVal = Node->getOperand(2);
900 if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal))
901 SrcReg = R->getReg();
903 SrcReg = getVR(SrcVal, VRBaseMap);
905 unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
906 if (SrcReg == DestReg) // Coalesced away the copy? Ignore.
909 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
910 DestReg).addReg(SrcReg);
913 case ISD::CopyFromReg: {
914 unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
915 EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap);
918 case ISD::EH_LABEL: {
919 MCSymbol *S = cast<EHLabelSDNode>(Node)->getLabel();
920 BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
921 TII->get(TargetOpcode::EH_LABEL)).addSym(S);
925 case ISD::LIFETIME_START:
926 case ISD::LIFETIME_END: {
927 unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START) ?
928 TargetOpcode::LIFETIME_START : TargetOpcode::LIFETIME_END;
930 FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Node->getOperand(1));
931 BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp))
932 .addFrameIndex(FI->getIndex());
936 case ISD::INLINEASM: {
937 unsigned NumOps = Node->getNumOperands();
938 if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue)
939 --NumOps; // Ignore the glue operand.
941 // Create the inline asm machine instruction.
942 MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(),
943 TII->get(TargetOpcode::INLINEASM));
945 // Add the asm string as an external symbol operand.
946 SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString);
947 const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol();
948 MIB.addExternalSymbol(AsmStr);
950 // Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore
953 cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))->
955 MIB.addImm(ExtraInfo);
957 // Remember to operand index of the group flags.
958 SmallVector<unsigned, 8> GroupIdx;
960 // Remember registers that are part of early-clobber defs.
961 SmallVector<unsigned, 8> ECRegs;
963 // Add all of the operand registers to the instruction.
964 for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) {
966 cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
967 const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
969 GroupIdx.push_back(MIB->getNumOperands());
971 ++i; // Skip the ID value.
973 switch (InlineAsm::getKind(Flags)) {
974 default: llvm_unreachable("Bad flags!");
975 case InlineAsm::Kind_RegDef:
976 for (unsigned j = 0; j != NumVals; ++j, ++i) {
977 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
978 // FIXME: Add dead flags for physical and virtual registers defined.
979 // For now, mark physical register defs as implicit to help fast
980 // regalloc. This makes inline asm look a lot like calls.
981 MIB.addReg(Reg, RegState::Define |
982 getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg)));
985 case InlineAsm::Kind_RegDefEarlyClobber:
986 case InlineAsm::Kind_Clobber:
987 for (unsigned j = 0; j != NumVals; ++j, ++i) {
988 unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
989 MIB.addReg(Reg, RegState::Define | RegState::EarlyClobber |
990 getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg)));
991 ECRegs.push_back(Reg);
994 case InlineAsm::Kind_RegUse: // Use of register.
995 case InlineAsm::Kind_Imm: // Immediate.
996 case InlineAsm::Kind_Mem: // Addressing mode.
997 // The addressing mode has been selected, just add all of the
998 // operands to the machine instruction.
999 for (unsigned j = 0; j != NumVals; ++j, ++i)
1000 AddOperand(MIB, Node->getOperand(i), 0, nullptr, VRBaseMap,
1001 /*IsDebug=*/false, IsClone, IsCloned);
1003 // Manually set isTied bits.
1004 if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) {
1005 unsigned DefGroup = 0;
1006 if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) {
1007 unsigned DefIdx = GroupIdx[DefGroup] + 1;
1008 unsigned UseIdx = GroupIdx.back() + 1;
1009 for (unsigned j = 0; j != NumVals; ++j)
1010 MIB->tieOperands(DefIdx + j, UseIdx + j);
1017 // GCC inline assembly allows input operands to also be early-clobber
1018 // output operands (so long as the operand is written only after it's
1019 // used), but this does not match the semantics of our early-clobber flag.
1020 // If an early-clobber operand register is also an input operand register,
1021 // then remove the early-clobber flag.
1022 for (unsigned Reg : ECRegs) {
1023 if (MIB->readsRegister(Reg, TRI)) {
1024 MachineOperand *MO = MIB->findRegisterDefOperand(Reg, false, TRI);
1025 assert(MO && "No def operand for clobbered register?");
1026 MO->setIsEarlyClobber(false);
1030 // Get the mdnode from the asm if it exists and add it to the instruction.
1031 SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode);
1032 const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD();
1034 MIB.addMetadata(MD);
1036 MBB->insert(InsertPos, MIB);
1042 /// InstrEmitter - Construct an InstrEmitter and set it to start inserting
1043 /// at the given position in the given block.
1044 InstrEmitter::InstrEmitter(MachineBasicBlock *mbb,
1045 MachineBasicBlock::iterator insertpos)
1046 : MF(mbb->getParent()), MRI(&MF->getRegInfo()),
1047 TII(MF->getSubtarget().getInstrInfo()),
1048 TRI(MF->getSubtarget().getRegisterInfo()),
1049 TLI(MF->getSubtarget().getTargetLowering()), MBB(mbb),
1050 InsertPos(insertpos) {}