1 //===- Thumb1RegisterInfo.cpp - Thumb-1 Register Information -------*- C++ -*-===//
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 file contains the Thumb-1 implementation of the TargetRegisterInfo class.
12 //===----------------------------------------------------------------------===//
15 #include "ARMAddressingModes.h"
16 #include "ARMBaseInstrInfo.h"
17 #include "ARMMachineFunctionInfo.h"
18 #include "ARMSubtarget.h"
19 #include "Thumb1InstrInfo.h"
20 #include "Thumb1RegisterInfo.h"
21 #include "llvm/Constants.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/Function.h"
24 #include "llvm/LLVMContext.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineFrameInfo.h"
27 #include "llvm/CodeGen/MachineFunction.h"
28 #include "llvm/CodeGen/MachineInstrBuilder.h"
29 #include "llvm/CodeGen/MachineLocation.h"
30 #include "llvm/CodeGen/MachineRegisterInfo.h"
31 #include "llvm/Target/TargetFrameInfo.h"
32 #include "llvm/Target/TargetMachine.h"
33 #include "llvm/ADT/BitVector.h"
34 #include "llvm/ADT/SmallVector.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Support/raw_ostream.h"
41 ThumbRegScavenging("enable-thumb-reg-scavenging",
43 cl::desc("Enable register scavenging on Thumb"));
45 Thumb1RegisterInfo::Thumb1RegisterInfo(const ARMBaseInstrInfo &tii,
46 const ARMSubtarget &sti)
47 : ARMBaseRegisterInfo(tii, sti) {
51 const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
52 return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
56 const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
57 return MIB.addReg(ARM::CPSR);
60 /// emitLoadConstPool - Emits a load from constpool to materialize the
61 /// specified immediate.
62 void Thumb1RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
63 MachineBasicBlock::iterator &MBBI,
65 unsigned DestReg, unsigned SubIdx,
67 ARMCC::CondCodes Pred,
68 unsigned PredReg) const {
69 MachineFunction &MF = *MBB.getParent();
70 MachineConstantPool *ConstantPool = MF.getConstantPool();
72 MF.getFunction()->getContext()->getConstantInt(Type::Int32Ty, Val);
73 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
75 BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRcp))
76 .addReg(DestReg, getDefRegState(true), SubIdx)
77 .addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg);
80 const TargetRegisterClass*
81 Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, MVT VT) const {
82 if (isARMLowRegister(Reg))
83 return ARM::tGPRRegisterClass;
87 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
88 case ARM::R12: case ARM::SP: case ARM::LR: case ARM::PC:
89 return ARM::GPRRegisterClass;
92 return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
96 Thumb1RegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
97 return ThumbRegScavenging;
100 bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
101 const MachineFrameInfo *FFI = MF.getFrameInfo();
102 unsigned CFSize = FFI->getMaxCallFrameSize();
103 // It's not always a good idea to include the call frame as part of the
104 // stack frame. ARM (especially Thumb) has small immediate offset to
105 // address the stack frame. So a large call frame can cause poor codegen
106 // and may even makes it impossible to scavenge a register.
107 if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
110 return !MF.getFrameInfo()->hasVarSizedObjects();
114 /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
115 /// a destreg = basereg + immediate in Thumb code. Materialize the immediate
116 /// in a register using mov / mvn sequences or load the immediate from a
119 void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
120 MachineBasicBlock::iterator &MBBI,
121 unsigned DestReg, unsigned BaseReg,
122 int NumBytes, bool CanChangeCC,
123 const TargetInstrInfo &TII,
124 const Thumb1RegisterInfo& MRI,
126 bool isHigh = !isARMLowRegister(DestReg) ||
127 (BaseReg != 0 && !isARMLowRegister(BaseReg));
129 // Subtract doesn't have high register version. Load the negative value
130 // if either base or dest register is a high register. Also, if do not
131 // issue sub as part of the sequence if condition register is to be
133 if (NumBytes < 0 && !isHigh && CanChangeCC) {
135 NumBytes = -NumBytes;
137 unsigned LdReg = DestReg;
138 if (DestReg == ARM::SP) {
139 assert(BaseReg == ARM::SP && "Unexpected!");
141 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
142 .addReg(ARM::R3, RegState::Kill);
145 if (NumBytes <= 255 && NumBytes >= 0)
146 AddDefaultCC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
148 else if (NumBytes < 0 && NumBytes >= -255) {
149 AddDefaultCC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
151 AddDefaultCC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg))
152 .addReg(LdReg, RegState::Kill);
154 MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes);
157 int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
158 MachineInstrBuilder MIB =
159 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
160 if (Opc != ARM::tADDhirr)
161 MIB = AddDefaultCC(MIB);
162 if (DestReg == ARM::SP || isSub)
163 MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
165 MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
168 if (DestReg == ARM::SP)
169 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
170 .addReg(ARM::R12, RegState::Kill);
173 /// calcNumMI - Returns the number of instructions required to materialize
174 /// the specific add / sub r, c instruction.
175 static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
176 unsigned NumBits, unsigned Scale) {
178 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
180 if (Opc == ARM::tADDrSPi) {
181 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
185 Scale = 1; // Followed by a number of tADDi8.
186 Chunk = ((1 << NumBits) - 1) * Scale;
189 NumMIs += Bytes / Chunk;
190 if ((Bytes % Chunk) != 0)
197 /// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
198 /// a destreg = basereg + immediate in Thumb code.
200 void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
201 MachineBasicBlock::iterator &MBBI,
202 unsigned DestReg, unsigned BaseReg,
203 int NumBytes, const TargetInstrInfo &TII,
204 const Thumb1RegisterInfo& MRI,
206 bool isSub = NumBytes < 0;
207 unsigned Bytes = (unsigned)NumBytes;
208 if (isSub) Bytes = -NumBytes;
209 bool isMul4 = (Bytes & 3) == 0;
210 bool isTwoAddr = false;
211 bool DstNotEqBase = false;
212 unsigned NumBits = 1;
217 bool NeedPred = false;
219 if (DestReg == BaseReg && BaseReg == ARM::SP) {
220 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
223 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
225 } else if (!isSub && BaseReg == ARM::SP) {
228 // r1 = add sp, 100 * 4
232 ExtraOpc = ARM::tADDi3;
241 if (DestReg != BaseReg)
244 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
245 NeedPred = NeedCC = true;
249 unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
250 unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
251 if (NumMIs > Threshold) {
252 // This will expand into too many instructions. Load the immediate from a
254 emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
260 if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
261 // If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
262 unsigned Chunk = (1 << 3) - 1;
263 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
265 const TargetInstrDesc &TID = TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3);
266 const MachineInstrBuilder MIB =
267 AddDefaultCC(BuildMI(MBB, MBBI, dl, TID, DestReg));
268 AddDefaultPred(MIB.addReg(BaseReg, RegState::Kill).addImm(ThisVal));
270 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
271 .addReg(BaseReg, RegState::Kill);
276 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
278 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
281 // Build the new tADD / tSUB.
283 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
285 MIB = AddDefaultCC(MIB);
286 MIB .addReg(DestReg).addImm(ThisVal);
288 MIB = AddDefaultPred(MIB);
291 bool isKill = BaseReg != ARM::SP;
292 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
294 MIB = AddDefaultCC(MIB);
295 MIB.addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
297 MIB = AddDefaultPred(MIB);
300 if (Opc == ARM::tADDrSPi) {
306 Chunk = ((1 << NumBits) - 1) * Scale;
307 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
308 NeedPred = NeedCC = isTwoAddr = true;
314 const TargetInstrDesc &TID = TII.get(ExtraOpc);
315 AddDefaultPred(AddDefaultCC(BuildMI(MBB, MBBI, dl, TID, DestReg))
316 .addReg(DestReg, RegState::Kill)
317 .addImm(((unsigned)NumBytes) & 3));
321 static void emitSPUpdate(MachineBasicBlock &MBB,
322 MachineBasicBlock::iterator &MBBI,
323 const TargetInstrInfo &TII, DebugLoc dl,
324 const Thumb1RegisterInfo &MRI,
326 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
330 void Thumb1RegisterInfo::
331 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
332 MachineBasicBlock::iterator I) const {
333 if (!hasReservedCallFrame(MF)) {
334 // If we have alloca, convert as follows:
335 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
336 // ADJCALLSTACKUP -> add, sp, sp, amount
337 MachineInstr *Old = I;
338 DebugLoc dl = Old->getDebugLoc();
339 unsigned Amount = Old->getOperand(0).getImm();
341 // We need to keep the stack aligned properly. To do this, we round the
342 // amount of space needed for the outgoing arguments up to the next
343 // alignment boundary.
344 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
345 Amount = (Amount+Align-1)/Align*Align;
347 // Replace the pseudo instruction with a new instruction...
348 unsigned Opc = Old->getOpcode();
349 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
350 emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
352 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
353 emitSPUpdate(MBB, I, TII, dl, *this, Amount);
360 /// emitThumbConstant - Emit a series of instructions to materialize a
362 static void emitThumbConstant(MachineBasicBlock &MBB,
363 MachineBasicBlock::iterator &MBBI,
364 unsigned DestReg, int Imm,
365 const TargetInstrInfo &TII,
366 const Thumb1RegisterInfo& MRI,
368 bool isSub = Imm < 0;
369 if (isSub) Imm = -Imm;
371 int Chunk = (1 << 8) - 1;
372 int ThisVal = (Imm > Chunk) ? Chunk : Imm;
374 AddDefaultPred(AddDefaultCC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8),
378 emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
380 const TargetInstrDesc &TID = TII.get(ARM::tRSB);
381 AddDefaultPred(AddDefaultCC(BuildMI(MBB, MBBI, dl, TID, DestReg))
382 .addReg(DestReg, RegState::Kill));
386 static void removeOperands(MachineInstr &MI, unsigned i) {
388 for (unsigned e = MI.getNumOperands(); i != e; ++i)
389 MI.RemoveOperand(Op);
392 void Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
393 int SPAdj, RegScavenger *RS) const{
395 MachineInstr &MI = *II;
396 MachineBasicBlock &MBB = *MI.getParent();
397 MachineFunction &MF = *MBB.getParent();
398 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
399 DebugLoc dl = MI.getDebugLoc();
401 while (!MI.getOperand(i).isFI()) {
403 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
406 unsigned FrameReg = ARM::SP;
407 int FrameIndex = MI.getOperand(i).getIndex();
408 int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
409 MF.getFrameInfo()->getStackSize() + SPAdj;
411 if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
412 Offset -= AFI->getGPRCalleeSavedArea1Offset();
413 else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
414 Offset -= AFI->getGPRCalleeSavedArea2Offset();
415 else if (hasFP(MF)) {
416 assert(SPAdj == 0 && "Unexpected");
417 // There is alloca()'s in this function, must reference off the frame
419 FrameReg = getFrameRegister(MF);
420 Offset -= AFI->getFramePtrSpillOffset();
423 unsigned Opcode = MI.getOpcode();
424 const TargetInstrDesc &Desc = MI.getDesc();
425 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
427 if (Opcode == ARM::tADDrSPi) {
428 Offset += MI.getOperand(i+1).getImm();
430 // Can't use tADDrSPi if it's based off the frame pointer.
431 unsigned NumBits = 0;
433 if (FrameReg != ARM::SP) {
434 Opcode = ARM::tADDi3;
435 MI.setDesc(TII.get(Opcode));
440 assert((Offset & 3) == 0 &&
441 "Thumb add/sub sp, #imm immediate must be multiple of 4!");
445 // Turn it into a move.
446 MI.setDesc(TII.get(ARM::tMOVhir2lor));
447 MI.getOperand(i).ChangeToRegister(FrameReg, false);
448 MI.RemoveOperand(i+1);
452 // Common case: small offset, fits into instruction.
453 unsigned Mask = (1 << NumBits) - 1;
454 if (((Offset / Scale) & ~Mask) == 0) {
455 // Replace the FrameIndex with sp / fp
456 if (Opcode == ARM::tADDi3) {
457 removeOperands(MI, i);
458 MachineInstrBuilder MIB(&MI);
459 AddDefaultPred(AddDefaultCC(MIB).addReg(FrameReg).addImm(Offset/Scale));
461 MI.getOperand(i).ChangeToRegister(FrameReg, false);
462 MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
467 unsigned DestReg = MI.getOperand(0).getReg();
468 unsigned Bytes = (Offset > 0) ? Offset : -Offset;
469 unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
470 // MI would expand into a large number of instructions. Don't try to
471 // simplify the immediate.
473 emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
480 // Translate r0 = add sp, imm to
481 // r0 = add sp, 255*4
482 // r0 = add r0, (imm - 255*4)
483 if (Opcode == ARM::tADDi3) {
484 removeOperands(MI, i);
485 MachineInstrBuilder MIB(&MI);
486 AddDefaultPred(AddDefaultCC(MIB).addReg(FrameReg).addImm(Mask));
488 MI.getOperand(i).ChangeToRegister(FrameReg, false);
489 MI.getOperand(i+1).ChangeToImmediate(Mask);
491 Offset = (Offset - Mask * Scale);
492 MachineBasicBlock::iterator NII = next(II);
493 emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
496 // Translate r0 = add sp, -imm to
497 // r0 = -imm (this is then translated into a series of instructons)
499 emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
500 MI.setDesc(TII.get(ARM::tADDhirr));
501 MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
502 MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
508 unsigned NumBits = 0;
511 case ARMII::AddrModeT1_s: {
513 InstrOffs = MI.getOperand(ImmIdx).getImm();
514 NumBits = (FrameReg == ARM::SP) ? 8 : 5;
519 llvm_unreachable("Unsupported addressing mode!");
523 Offset += InstrOffs * Scale;
524 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
526 // Common case: small offset, fits into instruction.
527 MachineOperand &ImmOp = MI.getOperand(ImmIdx);
528 int ImmedOffset = Offset / Scale;
529 unsigned Mask = (1 << NumBits) - 1;
530 if ((unsigned)Offset <= Mask * Scale) {
531 // Replace the FrameIndex with sp
532 MI.getOperand(i).ChangeToRegister(FrameReg, false);
533 ImmOp.ChangeToImmediate(ImmedOffset);
537 bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
538 if (AddrMode == ARMII::AddrModeT1_s) {
539 // Thumb tLDRspi, tSTRspi. These will change to instructions that use
540 // a different base register.
542 Mask = (1 << NumBits) - 1;
544 // If this is a thumb spill / restore, we will be using a constpool load to
545 // materialize the offset.
546 if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
547 ImmOp.ChangeToImmediate(0);
549 // Otherwise, it didn't fit. Pull in what we can to simplify the immed.
550 ImmedOffset = ImmedOffset & Mask;
551 ImmOp.ChangeToImmediate(ImmedOffset);
552 Offset &= ~(Mask*Scale);
556 // If we get here, the immediate doesn't fit into the instruction. We folded
557 // as much as possible above, handle the rest, providing a register that is
559 assert(Offset && "This code isn't needed if offset already handled!");
561 // Remove predicate first.
562 int PIdx = MI.findFirstPredOperandIdx();
564 removeOperands(MI, PIdx);
566 if (Desc.mayLoad()) {
567 // Use the destination register to materialize sp + offset.
568 unsigned TmpReg = MI.getOperand(0).getReg();
570 if (Opcode == ARM::tRestore) {
571 if (FrameReg == ARM::SP)
572 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
573 Offset, false, TII, *this, dl);
575 emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
579 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
583 MI.setDesc(TII.get(ARM::tLDR));
584 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
586 // Use [reg, reg] addrmode.
587 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
588 else // tLDR has an extra register operand.
589 MI.addOperand(MachineOperand::CreateReg(0, false));
590 } else if (Desc.mayStore()) {
591 // FIXME! This is horrific!!! We need register scavenging.
592 // Our temporary workaround has marked r3 unavailable. Of course, r3 is
593 // also a ABI register so it's possible that is is the register that is
594 // being storing here. If that's the case, we do the following:
596 // Use r2 to materialize sp + offset
599 unsigned ValReg = MI.getOperand(0).getReg();
600 unsigned TmpReg = ARM::R3;
602 if (ValReg == ARM::R3) {
603 BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
604 .addReg(ARM::R2, RegState::Kill);
607 if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
608 BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
609 .addReg(ARM::R3, RegState::Kill);
610 if (Opcode == ARM::tSpill) {
611 if (FrameReg == ARM::SP)
612 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
613 Offset, false, TII, *this, dl);
615 emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
619 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
621 MI.setDesc(TII.get(ARM::tSTR));
622 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
623 if (UseRR) // Use [reg, reg] addrmode.
624 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
625 else // tSTR has an extra register operand.
626 MI.addOperand(MachineOperand::CreateReg(0, false));
628 MachineBasicBlock::iterator NII = next(II);
629 if (ValReg == ARM::R3)
630 BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R2)
631 .addReg(ARM::R12, RegState::Kill);
632 if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
633 BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
634 .addReg(ARM::R12, RegState::Kill);
636 assert(false && "Unexpected opcode!");
638 // Add predicate back if it's needed.
639 if (MI.getDesc().isPredicable()) {
640 MachineInstrBuilder MIB(&MI);
645 void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const {
646 MachineBasicBlock &MBB = MF.front();
647 MachineBasicBlock::iterator MBBI = MBB.begin();
648 MachineFrameInfo *MFI = MF.getFrameInfo();
649 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
650 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
651 unsigned NumBytes = MFI->getStackSize();
652 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
653 DebugLoc dl = (MBBI != MBB.end() ?
654 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
656 // Check if R3 is live in. It might have to be used as a scratch register.
657 for (MachineRegisterInfo::livein_iterator I =MF.getRegInfo().livein_begin(),
658 E = MF.getRegInfo().livein_end(); I != E; ++I) {
659 if (I->first == ARM::R3) {
660 AFI->setR3IsLiveIn(true);
665 // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
666 NumBytes = (NumBytes + 3) & ~3;
667 MFI->setStackSize(NumBytes);
669 // Determine the sizes of each callee-save spill areas and record which frame
670 // belongs to which callee-save spill areas.
671 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
672 int FramePtrSpillFI = 0;
675 emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
677 if (!AFI->hasStackFrame()) {
679 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
683 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
684 unsigned Reg = CSI[i].getReg();
685 int FI = CSI[i].getFrameIdx();
693 FramePtrSpillFI = FI;
694 AFI->addGPRCalleeSavedArea1Frame(FI);
702 FramePtrSpillFI = FI;
703 if (STI.isTargetDarwin()) {
704 AFI->addGPRCalleeSavedArea2Frame(FI);
707 AFI->addGPRCalleeSavedArea1Frame(FI);
712 AFI->addDPRCalleeSavedAreaFrame(FI);
717 if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
719 if (MBBI != MBB.end())
720 dl = MBBI->getDebugLoc();
723 // Darwin ABI requires FP to point to the stack slot that contains the
725 if (STI.isTargetDarwin() || hasFP(MF)) {
726 MachineInstrBuilder MIB =
727 BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
728 .addFrameIndex(FramePtrSpillFI).addImm(0);
731 // Determine starting offsets of spill areas.
732 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
733 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
734 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
735 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
736 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
737 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
738 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
740 NumBytes = DPRCSOffset;
742 // Insert it after all the callee-save spills.
743 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
746 if (STI.isTargetELF() && hasFP(MF)) {
747 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
748 AFI->getFramePtrSpillOffset());
751 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
752 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
753 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
756 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
757 for (unsigned i = 0; CSRegs[i]; ++i)
758 if (Reg == CSRegs[i])
763 static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
764 return (MI->getOpcode() == ARM::tRestore &&
765 MI->getOperand(1).isFI() &&
766 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
769 void Thumb1RegisterInfo::emitEpilogue(MachineFunction &MF,
770 MachineBasicBlock &MBB) const {
771 MachineBasicBlock::iterator MBBI = prior(MBB.end());
772 assert((MBBI->getOpcode() == ARM::tBX_RET ||
773 MBBI->getOpcode() == ARM::tPOP_RET) &&
774 "Can only insert epilog into returning blocks");
775 DebugLoc dl = MBBI->getDebugLoc();
776 MachineFrameInfo *MFI = MF.getFrameInfo();
777 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
778 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
779 int NumBytes = (int)MFI->getStackSize();
781 if (!AFI->hasStackFrame()) {
783 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
785 // Unwind MBBI to point to first LDR / FLDD.
786 const unsigned *CSRegs = getCalleeSavedRegs();
787 if (MBBI != MBB.begin()) {
790 while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
791 if (!isCSRestore(MBBI, CSRegs))
795 // Move SP to start of FP callee save spill area.
796 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
797 AFI->getGPRCalleeSavedArea2Size() +
798 AFI->getDPRCalleeSavedAreaSize());
801 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
802 // Reset SP based on frame pointer only if the stack frame extends beyond
803 // frame pointer stack slot or target is ELF and the function has FP.
805 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
808 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::SP)
811 if (MBBI->getOpcode() == ARM::tBX_RET &&
812 &MBB.front() != MBBI &&
813 prior(MBBI)->getOpcode() == ARM::tPOP) {
814 MachineBasicBlock::iterator PMBBI = prior(MBBI);
815 emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
817 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
822 // Epilogue for vararg functions: pop LR to R3 and branch off it.
823 // FIXME: Verify this is still ok when R3 is no longer being reserved.
824 BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)).addReg(ARM::R3);
826 emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
828 BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg)).addReg(ARM::R3);