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