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/CodeGen/MachineConstantPool.h"
24 #include "llvm/CodeGen/MachineFrameInfo.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineInstrBuilder.h"
27 #include "llvm/CodeGen/MachineLocation.h"
28 #include "llvm/CodeGen/MachineRegisterInfo.h"
29 #include "llvm/Target/TargetFrameInfo.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/ADT/BitVector.h"
32 #include "llvm/ADT/SmallVector.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
39 ThumbRegScavenging("enable-thumb-reg-scavenging",
41 cl::desc("Enable register scavenging on Thumb"));
43 Thumb1RegisterInfo::Thumb1RegisterInfo(const ARMBaseInstrInfo &tii,
44 const ARMSubtarget &sti)
45 : ARMBaseRegisterInfo(tii, sti) {
48 /// emitLoadConstPool - Emits a load from constpool to materialize the
49 /// specified immediate.
50 void Thumb1RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
51 MachineBasicBlock::iterator &MBBI,
53 unsigned DestReg, int Val,
54 ARMCC::CondCodes Pred,
55 unsigned PredReg) const {
56 MachineFunction &MF = *MBB.getParent();
57 MachineConstantPool *ConstantPool = MF.getConstantPool();
58 Constant *C = ConstantInt::get(Type::Int32Ty, Val);
59 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
61 BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRcp), DestReg)
62 .addConstantPoolIndex(Idx);
65 const TargetRegisterClass*
66 Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, MVT VT) const {
67 if (isARMLowRegister(Reg))
68 return ARM::tGPRRegisterClass;
72 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
73 case ARM::R12: case ARM::SP: case ARM::LR: case ARM::PC:
74 return ARM::GPRRegisterClass;
77 return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
81 Thumb1RegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
82 return ThumbRegScavenging;
85 bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
86 const MachineFrameInfo *FFI = MF.getFrameInfo();
87 unsigned CFSize = FFI->getMaxCallFrameSize();
88 // It's not always a good idea to include the call frame as part of the
89 // stack frame. ARM (especially Thumb) has small immediate offset to
90 // address the stack frame. So a large call frame can cause poor codegen
91 // and may even makes it impossible to scavenge a register.
92 if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
95 return !MF.getFrameInfo()->hasVarSizedObjects();
98 /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
99 /// a destreg = basereg + immediate in Thumb code. Materialize the immediate
100 /// in a register using mov / mvn sequences or load the immediate from a
103 void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
104 MachineBasicBlock::iterator &MBBI,
105 unsigned DestReg, unsigned BaseReg,
106 int NumBytes, bool CanChangeCC,
107 const TargetInstrInfo &TII,
108 const Thumb1RegisterInfo& MRI,
110 bool isHigh = !isARMLowRegister(DestReg) ||
111 (BaseReg != 0 && !isARMLowRegister(BaseReg));
113 // Subtract doesn't have high register version. Load the negative value
114 // if either base or dest register is a high register. Also, if do not
115 // issue sub as part of the sequence if condition register is to be
117 if (NumBytes < 0 && !isHigh && CanChangeCC) {
119 NumBytes = -NumBytes;
121 unsigned LdReg = DestReg;
122 if (DestReg == ARM::SP) {
123 assert(BaseReg == ARM::SP && "Unexpected!");
125 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
126 .addReg(ARM::R3, RegState::Kill);
129 if (NumBytes <= 255 && NumBytes >= 0)
130 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg).addImm(NumBytes);
131 else if (NumBytes < 0 && NumBytes >= -255) {
132 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg).addImm(NumBytes);
133 BuildMI(MBB, MBBI, dl, TII.get(ARM::tNEG), LdReg)
134 .addReg(LdReg, RegState::Kill);
136 MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, NumBytes);
139 int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
140 const MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl,
141 TII.get(Opc), DestReg);
142 if (DestReg == ARM::SP || isSub)
143 MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
145 MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
146 if (DestReg == ARM::SP)
147 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
148 .addReg(ARM::R12, RegState::Kill);
151 /// calcNumMI - Returns the number of instructions required to materialize
152 /// the specific add / sub r, c instruction.
153 static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
154 unsigned NumBits, unsigned Scale) {
156 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
158 if (Opc == ARM::tADDrSPi) {
159 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
163 Scale = 1; // Followed by a number of tADDi8.
164 Chunk = ((1 << NumBits) - 1) * Scale;
167 NumMIs += Bytes / Chunk;
168 if ((Bytes % Chunk) != 0)
175 /// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
176 /// a destreg = basereg + immediate in Thumb code.
178 void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
179 MachineBasicBlock::iterator &MBBI,
180 unsigned DestReg, unsigned BaseReg,
181 int NumBytes, const TargetInstrInfo &TII,
182 const Thumb1RegisterInfo& MRI,
184 bool isSub = NumBytes < 0;
185 unsigned Bytes = (unsigned)NumBytes;
186 if (isSub) Bytes = -NumBytes;
187 bool isMul4 = (Bytes & 3) == 0;
188 bool isTwoAddr = false;
189 bool DstNotEqBase = false;
190 unsigned NumBits = 1;
195 if (DestReg == BaseReg && BaseReg == ARM::SP) {
196 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
199 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
201 } else if (!isSub && BaseReg == ARM::SP) {
204 // r1 = add sp, 100 * 4
208 ExtraOpc = ARM::tADDi3;
217 if (DestReg != BaseReg)
220 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
224 unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
225 unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
226 if (NumMIs > Threshold) {
227 // This will expand into too many instructions. Load the immediate from a
229 emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
235 if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
236 // If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
237 unsigned Chunk = (1 << 3) - 1;
238 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
240 BuildMI(MBB, MBBI, dl,TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3), DestReg)
241 .addReg(BaseReg, RegState::Kill).addImm(ThisVal);
243 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
244 .addReg(BaseReg, RegState::Kill);
249 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
251 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
254 // Build the new tADD / tSUB.
256 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
257 .addReg(DestReg).addImm(ThisVal);
259 bool isKill = BaseReg != ARM::SP;
260 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
261 .addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
264 if (Opc == ARM::tADDrSPi) {
270 Chunk = ((1 << NumBits) - 1) * Scale;
271 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
278 BuildMI(MBB, MBBI, dl, TII.get(ExtraOpc), DestReg)
279 .addReg(DestReg, RegState::Kill)
280 .addImm(((unsigned)NumBytes) & 3);
283 static void emitSPUpdate(MachineBasicBlock &MBB,
284 MachineBasicBlock::iterator &MBBI,
285 const TargetInstrInfo &TII, DebugLoc dl,
286 const Thumb1RegisterInfo &MRI,
288 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
292 void Thumb1RegisterInfo::
293 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
294 MachineBasicBlock::iterator I) const {
295 if (!hasReservedCallFrame(MF)) {
296 // If we have alloca, convert as follows:
297 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
298 // ADJCALLSTACKUP -> add, sp, sp, amount
299 MachineInstr *Old = I;
300 DebugLoc dl = Old->getDebugLoc();
301 unsigned Amount = Old->getOperand(0).getImm();
303 // We need to keep the stack aligned properly. To do this, we round the
304 // amount of space needed for the outgoing arguments up to the next
305 // alignment boundary.
306 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
307 Amount = (Amount+Align-1)/Align*Align;
309 // Replace the pseudo instruction with a new instruction...
310 unsigned Opc = Old->getOpcode();
311 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
312 emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
314 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
315 emitSPUpdate(MBB, I, TII, dl, *this, Amount);
322 /// emitThumbConstant - Emit a series of instructions to materialize a
324 static void emitThumbConstant(MachineBasicBlock &MBB,
325 MachineBasicBlock::iterator &MBBI,
326 unsigned DestReg, int Imm,
327 const TargetInstrInfo &TII,
328 const Thumb1RegisterInfo& MRI,
330 bool isSub = Imm < 0;
331 if (isSub) Imm = -Imm;
333 int Chunk = (1 << 8) - 1;
334 int ThisVal = (Imm > Chunk) ? Chunk : Imm;
336 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), DestReg).addImm(ThisVal);
338 emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
340 BuildMI(MBB, MBBI, dl, TII.get(ARM::tNEG), DestReg)
341 .addReg(DestReg, RegState::Kill);
344 void Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
345 int SPAdj, RegScavenger *RS) const{
347 MachineInstr &MI = *II;
348 MachineBasicBlock &MBB = *MI.getParent();
349 MachineFunction &MF = *MBB.getParent();
350 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
351 DebugLoc dl = MI.getDebugLoc();
353 while (!MI.getOperand(i).isFI()) {
355 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
358 unsigned FrameReg = ARM::SP;
359 int FrameIndex = MI.getOperand(i).getIndex();
360 int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
361 MF.getFrameInfo()->getStackSize() + SPAdj;
363 if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
364 Offset -= AFI->getGPRCalleeSavedArea1Offset();
365 else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
366 Offset -= AFI->getGPRCalleeSavedArea2Offset();
367 else if (hasFP(MF)) {
368 assert(SPAdj == 0 && "Unexpected");
369 // There is alloca()'s in this function, must reference off the frame
371 FrameReg = getFrameRegister(MF);
372 Offset -= AFI->getFramePtrSpillOffset();
375 unsigned Opcode = MI.getOpcode();
376 const TargetInstrDesc &Desc = MI.getDesc();
377 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
379 if (Opcode == ARM::tADDrSPi) {
380 Offset += MI.getOperand(i+1).getImm();
382 // Can't use tADDrSPi if it's based off the frame pointer.
383 unsigned NumBits = 0;
385 if (FrameReg != ARM::SP) {
386 Opcode = ARM::tADDi3;
387 MI.setDesc(TII.get(ARM::tADDi3));
392 assert((Offset & 3) == 0 &&
393 "Thumb add/sub sp, #imm immediate must be multiple of 4!");
397 // Turn it into a move.
398 MI.setDesc(TII.get(ARM::tMOVhir2lor));
399 MI.getOperand(i).ChangeToRegister(FrameReg, false);
400 MI.RemoveOperand(i+1);
404 // Common case: small offset, fits into instruction.
405 unsigned Mask = (1 << NumBits) - 1;
406 if (((Offset / Scale) & ~Mask) == 0) {
407 // Replace the FrameIndex with sp / fp
408 MI.getOperand(i).ChangeToRegister(FrameReg, false);
409 MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
413 unsigned DestReg = MI.getOperand(0).getReg();
414 unsigned Bytes = (Offset > 0) ? Offset : -Offset;
415 unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
416 // MI would expand into a large number of instructions. Don't try to
417 // simplify the immediate.
419 emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
426 // Translate r0 = add sp, imm to
427 // r0 = add sp, 255*4
428 // r0 = add r0, (imm - 255*4)
429 MI.getOperand(i).ChangeToRegister(FrameReg, false);
430 MI.getOperand(i+1).ChangeToImmediate(Mask);
431 Offset = (Offset - Mask * Scale);
432 MachineBasicBlock::iterator NII = next(II);
433 emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
436 // Translate r0 = add sp, -imm to
437 // r0 = -imm (this is then translated into a series of instructons)
439 emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
440 MI.setDesc(TII.get(ARM::tADDhirr));
441 MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
442 MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
448 unsigned NumBits = 0;
451 case ARMII::AddrModeT1_s: {
453 InstrOffs = MI.getOperand(ImmIdx).getImm();
454 NumBits = (FrameReg == ARM::SP) ? 8 : 5;
459 LLVM_UNREACHABLE("Unsupported addressing mode!");
463 Offset += InstrOffs * Scale;
464 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
466 // Common case: small offset, fits into instruction.
467 MachineOperand &ImmOp = MI.getOperand(ImmIdx);
468 int ImmedOffset = Offset / Scale;
469 unsigned Mask = (1 << NumBits) - 1;
470 if ((unsigned)Offset <= Mask * Scale) {
471 // Replace the FrameIndex with sp
472 MI.getOperand(i).ChangeToRegister(FrameReg, false);
473 ImmOp.ChangeToImmediate(ImmedOffset);
477 bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
478 if (AddrMode == ARMII::AddrModeT1_s) {
479 // Thumb tLDRspi, tSTRspi. These will change to instructions that use
480 // a different base register.
482 Mask = (1 << NumBits) - 1;
484 // If this is a thumb spill / restore, we will be using a constpool load to
485 // materialize the offset.
486 if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
487 ImmOp.ChangeToImmediate(0);
489 // Otherwise, it didn't fit. Pull in what we can to simplify the immed.
490 ImmedOffset = ImmedOffset & Mask;
491 ImmOp.ChangeToImmediate(ImmedOffset);
492 Offset &= ~(Mask*Scale);
496 // If we get here, the immediate doesn't fit into the instruction. We folded
497 // as much as possible above, handle the rest, providing a register that is
499 assert(Offset && "This code isn't needed if offset already handled!");
501 if (Desc.mayLoad()) {
502 // Use the destination register to materialize sp + offset.
503 unsigned TmpReg = MI.getOperand(0).getReg();
505 if (Opcode == ARM::tRestore) {
506 if (FrameReg == ARM::SP)
507 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
508 Offset, false, TII, *this, dl);
510 emitLoadConstPool(MBB, II, dl, TmpReg, Offset);
514 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
516 MI.setDesc(TII.get(ARM::tLDR));
517 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
519 // Use [reg, reg] addrmode.
520 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
521 else // tLDR has an extra register operand.
522 MI.addOperand(MachineOperand::CreateReg(0, false));
523 } else if (Desc.mayStore()) {
524 // FIXME! This is horrific!!! We need register scavenging.
525 // Our temporary workaround has marked r3 unavailable. Of course, r3 is
526 // also a ABI register so it's possible that is is the register that is
527 // being storing here. If that's the case, we do the following:
529 // Use r2 to materialize sp + offset
532 unsigned ValReg = MI.getOperand(0).getReg();
533 unsigned TmpReg = ARM::R3;
535 if (ValReg == ARM::R3) {
536 BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
537 .addReg(ARM::R2, RegState::Kill);
540 if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
541 BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
542 .addReg(ARM::R3, RegState::Kill);
543 if (Opcode == ARM::tSpill) {
544 if (FrameReg == ARM::SP)
545 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
546 Offset, false, TII, *this, dl);
548 emitLoadConstPool(MBB, II, dl, TmpReg, Offset);
552 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
554 MI.setDesc(TII.get(ARM::tSTR));
555 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
556 if (UseRR) // Use [reg, reg] addrmode.
557 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
558 else // tSTR has an extra register operand.
559 MI.addOperand(MachineOperand::CreateReg(0, false));
561 MachineBasicBlock::iterator NII = next(II);
562 if (ValReg == ARM::R3)
563 BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R2)
564 .addReg(ARM::R12, RegState::Kill);
565 if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
566 BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
567 .addReg(ARM::R12, RegState::Kill);
569 assert(false && "Unexpected opcode!");
572 void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const {
573 MachineBasicBlock &MBB = MF.front();
574 MachineBasicBlock::iterator MBBI = MBB.begin();
575 MachineFrameInfo *MFI = MF.getFrameInfo();
576 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
577 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
578 unsigned NumBytes = MFI->getStackSize();
579 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
580 DebugLoc dl = (MBBI != MBB.end() ?
581 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
583 // Check if R3 is live in. It might have to be used as a scratch register.
584 for (MachineRegisterInfo::livein_iterator I =MF.getRegInfo().livein_begin(),
585 E = MF.getRegInfo().livein_end(); I != E; ++I) {
586 if (I->first == ARM::R3) {
587 AFI->setR3IsLiveIn(true);
592 // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
593 NumBytes = (NumBytes + 3) & ~3;
594 MFI->setStackSize(NumBytes);
596 // Determine the sizes of each callee-save spill areas and record which frame
597 // belongs to which callee-save spill areas.
598 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
599 int FramePtrSpillFI = 0;
602 emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
604 if (!AFI->hasStackFrame()) {
606 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
610 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
611 unsigned Reg = CSI[i].getReg();
612 int FI = CSI[i].getFrameIdx();
620 FramePtrSpillFI = FI;
621 AFI->addGPRCalleeSavedArea1Frame(FI);
629 FramePtrSpillFI = FI;
630 if (STI.isTargetDarwin()) {
631 AFI->addGPRCalleeSavedArea2Frame(FI);
634 AFI->addGPRCalleeSavedArea1Frame(FI);
639 AFI->addDPRCalleeSavedAreaFrame(FI);
644 if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
646 if (MBBI != MBB.end())
647 dl = MBBI->getDebugLoc();
650 // Darwin ABI requires FP to point to the stack slot that contains the
652 if (STI.isTargetDarwin() || hasFP(MF)) {
653 MachineInstrBuilder MIB =
654 BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
655 .addFrameIndex(FramePtrSpillFI).addImm(0);
658 // Determine starting offsets of spill areas.
659 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
660 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
661 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
662 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
663 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
664 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
665 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
667 NumBytes = DPRCSOffset;
669 // Insert it after all the callee-save spills.
670 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
673 if (STI.isTargetELF() && hasFP(MF)) {
674 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
675 AFI->getFramePtrSpillOffset());
678 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
679 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
680 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
683 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
684 for (unsigned i = 0; CSRegs[i]; ++i)
685 if (Reg == CSRegs[i])
690 static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
691 return (MI->getOpcode() == ARM::tRestore &&
692 MI->getOperand(1).isFI() &&
693 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
696 void Thumb1RegisterInfo::emitEpilogue(MachineFunction &MF,
697 MachineBasicBlock &MBB) const {
698 MachineBasicBlock::iterator MBBI = prior(MBB.end());
699 assert((MBBI->getOpcode() == ARM::tBX_RET ||
700 MBBI->getOpcode() == ARM::tPOP_RET) &&
701 "Can only insert epilog into returning blocks");
702 DebugLoc dl = MBBI->getDebugLoc();
703 MachineFrameInfo *MFI = MF.getFrameInfo();
704 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
705 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
706 int NumBytes = (int)MFI->getStackSize();
708 if (!AFI->hasStackFrame()) {
710 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
712 // Unwind MBBI to point to first LDR / FLDD.
713 const unsigned *CSRegs = getCalleeSavedRegs();
714 if (MBBI != MBB.begin()) {
717 while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
718 if (!isCSRestore(MBBI, CSRegs))
722 // Move SP to start of FP callee save spill area.
723 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
724 AFI->getGPRCalleeSavedArea2Size() +
725 AFI->getDPRCalleeSavedAreaSize());
728 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
729 // Reset SP based on frame pointer only if the stack frame extends beyond
730 // frame pointer stack slot or target is ELF and the function has FP.
732 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
735 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::SP)
738 if (MBBI->getOpcode() == ARM::tBX_RET &&
739 &MBB.front() != MBBI &&
740 prior(MBBI)->getOpcode() == ARM::tPOP) {
741 MachineBasicBlock::iterator PMBBI = prior(MBBI);
742 emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
744 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
749 // Epilogue for vararg functions: pop LR to R3 and branch off it.
750 // FIXME: Verify this is still ok when R3 is no longer being reserved.
751 BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)).addReg(ARM::R3);
753 emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
755 BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg)).addReg(ARM::R3);