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/ErrorHandling.h"
36 #include "llvm/Support/raw_ostream.h"
39 Thumb1RegisterInfo::Thumb1RegisterInfo(const ARMBaseInstrInfo &tii,
40 const ARMSubtarget &sti)
41 : ARMBaseRegisterInfo(tii, sti) {
44 /// emitLoadConstPool - Emits a load from constpool to materialize the
45 /// specified immediate.
46 void Thumb1RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
47 MachineBasicBlock::iterator &MBBI,
49 unsigned DestReg, unsigned SubIdx,
51 ARMCC::CondCodes Pred,
52 unsigned PredReg) const {
53 MachineFunction &MF = *MBB.getParent();
54 MachineConstantPool *ConstantPool = MF.getConstantPool();
55 Constant *C = ConstantInt::get(
56 Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
57 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
59 BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRcp))
60 .addReg(DestReg, getDefRegState(true), SubIdx)
61 .addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg);
64 const TargetRegisterClass*
65 Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, EVT VT) const {
66 if (isARMLowRegister(Reg))
67 return ARM::tGPRRegisterClass;
71 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
72 case ARM::R12: case ARM::SP: case ARM::LR: case ARM::PC:
73 return ARM::GPRRegisterClass;
76 return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
79 bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
80 const MachineFrameInfo *FFI = MF.getFrameInfo();
81 unsigned CFSize = FFI->getMaxCallFrameSize();
82 // It's not always a good idea to include the call frame as part of the
83 // stack frame. ARM (especially Thumb) has small immediate offset to
84 // address the stack frame. So a large call frame can cause poor codegen
85 // and may even makes it impossible to scavenge a register.
86 if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
89 return !MF.getFrameInfo()->hasVarSizedObjects();
93 /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
94 /// a destreg = basereg + immediate in Thumb code. Materialize the immediate
95 /// in a register using mov / mvn sequences or load the immediate from a
98 void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
99 MachineBasicBlock::iterator &MBBI,
100 unsigned DestReg, unsigned BaseReg,
101 int NumBytes, bool CanChangeCC,
102 const TargetInstrInfo &TII,
103 const Thumb1RegisterInfo& MRI,
105 MachineFunction &MF = *MBB.getParent();
106 bool isHigh = !isARMLowRegister(DestReg) ||
107 (BaseReg != 0 && !isARMLowRegister(BaseReg));
109 // Subtract doesn't have high register version. Load the negative value
110 // if either base or dest register is a high register. Also, if do not
111 // issue sub as part of the sequence if condition register is to be
113 if (NumBytes < 0 && !isHigh && CanChangeCC) {
115 NumBytes = -NumBytes;
117 unsigned LdReg = DestReg;
118 if (DestReg == ARM::SP) {
119 assert(BaseReg == ARM::SP && "Unexpected!");
120 LdReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
123 if (NumBytes <= 255 && NumBytes >= 0)
124 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
126 else if (NumBytes < 0 && NumBytes >= -255) {
127 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
129 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg))
130 .addReg(LdReg, RegState::Kill);
132 MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes);
135 int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
136 MachineInstrBuilder MIB =
137 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
138 if (Opc != ARM::tADDhirr)
139 MIB = AddDefaultT1CC(MIB);
140 if (DestReg == ARM::SP || isSub)
141 MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
143 MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
147 /// calcNumMI - Returns the number of instructions required to materialize
148 /// the specific add / sub r, c instruction.
149 static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
150 unsigned NumBits, unsigned Scale) {
152 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
154 if (Opc == ARM::tADDrSPi) {
155 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
159 Scale = 1; // Followed by a number of tADDi8.
160 Chunk = ((1 << NumBits) - 1) * Scale;
163 NumMIs += Bytes / Chunk;
164 if ((Bytes % Chunk) != 0)
171 /// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
172 /// a destreg = basereg + immediate in Thumb code.
174 void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
175 MachineBasicBlock::iterator &MBBI,
176 unsigned DestReg, unsigned BaseReg,
177 int NumBytes, const TargetInstrInfo &TII,
178 const Thumb1RegisterInfo& MRI,
180 bool isSub = NumBytes < 0;
181 unsigned Bytes = (unsigned)NumBytes;
182 if (isSub) Bytes = -NumBytes;
183 bool isMul4 = (Bytes & 3) == 0;
184 bool isTwoAddr = false;
185 bool DstNotEqBase = false;
186 unsigned NumBits = 1;
191 bool NeedPred = false;
193 if (DestReg == BaseReg && BaseReg == ARM::SP) {
194 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
197 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
199 } else if (!isSub && BaseReg == ARM::SP) {
202 // r1 = add sp, 100 * 4
206 ExtraOpc = ARM::tADDi3;
215 if (DestReg != BaseReg)
218 if (DestReg == ARM::SP) {
219 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
220 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
224 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
226 NeedPred = NeedCC = true;
231 unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
232 unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
233 if (NumMIs > Threshold) {
234 // This will expand into too many instructions. Load the immediate from a
236 emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
242 if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
243 // If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
244 unsigned Chunk = (1 << 3) - 1;
245 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
247 const TargetInstrDesc &TID = TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3);
248 const MachineInstrBuilder MIB =
249 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg));
250 AddDefaultPred(MIB.addReg(BaseReg, RegState::Kill).addImm(ThisVal));
252 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
253 .addReg(BaseReg, RegState::Kill);
258 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
260 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
263 // Build the new tADD / tSUB.
265 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
267 MIB = AddDefaultT1CC(MIB);
268 MIB .addReg(DestReg).addImm(ThisVal);
270 MIB = AddDefaultPred(MIB);
273 bool isKill = BaseReg != ARM::SP;
274 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
276 MIB = AddDefaultT1CC(MIB);
277 MIB.addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
279 MIB = AddDefaultPred(MIB);
282 if (Opc == ARM::tADDrSPi) {
288 Chunk = ((1 << NumBits) - 1) * Scale;
289 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
290 NeedPred = NeedCC = isTwoAddr = true;
296 const TargetInstrDesc &TID = TII.get(ExtraOpc);
297 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
298 .addReg(DestReg, RegState::Kill)
299 .addImm(((unsigned)NumBytes) & 3));
303 static void emitSPUpdate(MachineBasicBlock &MBB,
304 MachineBasicBlock::iterator &MBBI,
305 const TargetInstrInfo &TII, DebugLoc dl,
306 const Thumb1RegisterInfo &MRI,
308 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
312 void Thumb1RegisterInfo::
313 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
314 MachineBasicBlock::iterator I) const {
315 if (!hasReservedCallFrame(MF)) {
316 // If we have alloca, convert as follows:
317 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
318 // ADJCALLSTACKUP -> add, sp, sp, amount
319 MachineInstr *Old = I;
320 DebugLoc dl = Old->getDebugLoc();
321 unsigned Amount = Old->getOperand(0).getImm();
323 // We need to keep the stack aligned properly. To do this, we round the
324 // amount of space needed for the outgoing arguments up to the next
325 // alignment boundary.
326 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
327 Amount = (Amount+Align-1)/Align*Align;
329 // Replace the pseudo instruction with a new instruction...
330 unsigned Opc = Old->getOpcode();
331 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
332 emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
334 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
335 emitSPUpdate(MBB, I, TII, dl, *this, Amount);
342 /// emitThumbConstant - Emit a series of instructions to materialize a
344 static void emitThumbConstant(MachineBasicBlock &MBB,
345 MachineBasicBlock::iterator &MBBI,
346 unsigned DestReg, int Imm,
347 const TargetInstrInfo &TII,
348 const Thumb1RegisterInfo& MRI,
350 bool isSub = Imm < 0;
351 if (isSub) Imm = -Imm;
353 int Chunk = (1 << 8) - 1;
354 int ThisVal = (Imm > Chunk) ? Chunk : Imm;
356 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8),
360 emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
362 const TargetInstrDesc &TID = TII.get(ARM::tRSB);
363 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
364 .addReg(DestReg, RegState::Kill));
368 static void removeOperands(MachineInstr &MI, unsigned i) {
370 for (unsigned e = MI.getNumOperands(); i != e; ++i)
371 MI.RemoveOperand(Op);
374 int Thumb1RegisterInfo::
375 rewriteFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
376 unsigned FrameReg, int Offset,
377 unsigned MOVOpc, unsigned ADDriOpc, unsigned SUBriOpc) const
379 // if/when eliminateFrameIndex() conforms with ARMBaseRegisterInfo
380 // version then can pull out Thumb1 specific parts here
384 /// saveScavengerRegister - Spill the register so it can be used by the
385 /// register scavenger. Return true.
387 Thumb1RegisterInfo::saveScavengerRegister(MachineBasicBlock &MBB,
388 MachineBasicBlock::iterator I,
389 MachineBasicBlock::iterator &UseMI,
390 const TargetRegisterClass *RC,
391 unsigned Reg) const {
392 // Thumb1 can't use the emergency spill slot on the stack because
393 // ldr/str immediate offsets must be positive, and if we're referencing
394 // off the frame pointer (if, for example, there are alloca() calls in
395 // the function, the offset will be negative. Use R12 instead since that's
396 // a call clobbered register that we know won't be used in Thumb1 mode.
397 DebugLoc DL = DebugLoc::getUnknownLoc();
398 BuildMI(MBB, I, DL, TII.get(ARM::tMOVtgpr2gpr)).
399 addReg(ARM::R12, RegState::Define).addReg(Reg, RegState::Kill);
401 // The UseMI is where we would like to restore the register. If there's
402 // interference with R12 before then, however, we'll need to restore it
403 // before that instead and adjust the UseMI.
405 for (MachineBasicBlock::iterator II = I; !done && II != UseMI ; ++II) {
406 // If this instruction affects R12, adjust our restore point.
407 for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
408 const MachineOperand &MO = II->getOperand(i);
409 if (!MO.isReg() || MO.isUndef() || !MO.getReg() ||
410 TargetRegisterInfo::isVirtualRegister(MO.getReg()))
412 if (MO.getReg() == ARM::R12) {
419 // Restore the register from R12
420 BuildMI(MBB, UseMI, DL, TII.get(ARM::tMOVgpr2tgpr)).
421 addReg(Reg, RegState::Define).addReg(ARM::R12, RegState::Kill);
427 Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
428 int SPAdj, int *Value,
429 RegScavenger *RS) const{
432 MachineInstr &MI = *II;
433 MachineBasicBlock &MBB = *MI.getParent();
434 MachineFunction &MF = *MBB.getParent();
435 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
436 DebugLoc dl = MI.getDebugLoc();
438 while (!MI.getOperand(i).isFI()) {
440 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
443 unsigned FrameReg = ARM::SP;
444 int FrameIndex = MI.getOperand(i).getIndex();
445 int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
446 MF.getFrameInfo()->getStackSize() + SPAdj;
448 if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
449 Offset -= AFI->getGPRCalleeSavedArea1Offset();
450 else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
451 Offset -= AFI->getGPRCalleeSavedArea2Offset();
452 else if (hasFP(MF)) {
453 assert(SPAdj == 0 && "Unexpected");
454 // There is alloca()'s in this function, must reference off the frame
456 FrameReg = getFrameRegister(MF);
457 Offset -= AFI->getFramePtrSpillOffset();
460 unsigned Opcode = MI.getOpcode();
461 const TargetInstrDesc &Desc = MI.getDesc();
462 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
464 if (Opcode == ARM::tADDrSPi) {
465 Offset += MI.getOperand(i+1).getImm();
467 // Can't use tADDrSPi if it's based off the frame pointer.
468 unsigned NumBits = 0;
470 if (FrameReg != ARM::SP) {
471 Opcode = ARM::tADDi3;
472 MI.setDesc(TII.get(Opcode));
477 assert((Offset & 3) == 0 &&
478 "Thumb add/sub sp, #imm immediate must be multiple of 4!");
482 // Turn it into a move.
483 MI.setDesc(TII.get(ARM::tMOVgpr2tgpr));
484 MI.getOperand(i).ChangeToRegister(FrameReg, false);
485 MI.RemoveOperand(i+1);
489 // Common case: small offset, fits into instruction.
490 unsigned Mask = (1 << NumBits) - 1;
491 if (((Offset / Scale) & ~Mask) == 0) {
492 // Replace the FrameIndex with sp / fp
493 if (Opcode == ARM::tADDi3) {
494 removeOperands(MI, i);
495 MachineInstrBuilder MIB(&MI);
496 AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg)
497 .addImm(Offset / Scale));
499 MI.getOperand(i).ChangeToRegister(FrameReg, false);
500 MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
505 unsigned DestReg = MI.getOperand(0).getReg();
506 unsigned Bytes = (Offset > 0) ? Offset : -Offset;
507 unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
508 // MI would expand into a large number of instructions. Don't try to
509 // simplify the immediate.
511 emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
518 // Translate r0 = add sp, imm to
519 // r0 = add sp, 255*4
520 // r0 = add r0, (imm - 255*4)
521 if (Opcode == ARM::tADDi3) {
522 removeOperands(MI, i);
523 MachineInstrBuilder MIB(&MI);
524 AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg).addImm(Mask));
526 MI.getOperand(i).ChangeToRegister(FrameReg, false);
527 MI.getOperand(i+1).ChangeToImmediate(Mask);
529 Offset = (Offset - Mask * Scale);
530 MachineBasicBlock::iterator NII = next(II);
531 emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
534 // Translate r0 = add sp, -imm to
535 // r0 = -imm (this is then translated into a series of instructons)
537 emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
539 MI.setDesc(TII.get(ARM::tADDhirr));
540 MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
541 MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
542 if (Opcode == ARM::tADDi3) {
543 MachineInstrBuilder MIB(&MI);
551 unsigned NumBits = 0;
554 case ARMII::AddrModeT1_s: {
556 InstrOffs = MI.getOperand(ImmIdx).getImm();
557 NumBits = (FrameReg == ARM::SP) ? 8 : 5;
562 llvm_unreachable("Unsupported addressing mode!");
566 Offset += InstrOffs * Scale;
567 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
569 // Common case: small offset, fits into instruction.
570 MachineOperand &ImmOp = MI.getOperand(ImmIdx);
571 int ImmedOffset = Offset / Scale;
572 unsigned Mask = (1 << NumBits) - 1;
573 if ((unsigned)Offset <= Mask * Scale) {
574 // Replace the FrameIndex with sp
575 MI.getOperand(i).ChangeToRegister(FrameReg, false);
576 ImmOp.ChangeToImmediate(ImmedOffset);
580 bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
581 if (AddrMode == ARMII::AddrModeT1_s) {
582 // Thumb tLDRspi, tSTRspi. These will change to instructions that use
583 // a different base register.
585 Mask = (1 << NumBits) - 1;
587 // If this is a thumb spill / restore, we will be using a constpool load to
588 // materialize the offset.
589 if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
590 ImmOp.ChangeToImmediate(0);
592 // Otherwise, it didn't fit. Pull in what we can to simplify the immed.
593 ImmedOffset = ImmedOffset & Mask;
594 ImmOp.ChangeToImmediate(ImmedOffset);
595 Offset &= ~(Mask*Scale);
599 // If we get here, the immediate doesn't fit into the instruction. We folded
600 // as much as possible above, handle the rest, providing a register that is
602 assert(Offset && "This code isn't needed if offset already handled!");
604 // Remove predicate first.
605 int PIdx = MI.findFirstPredOperandIdx();
607 removeOperands(MI, PIdx);
609 if (Desc.mayLoad()) {
610 // Use the destination register to materialize sp + offset.
611 unsigned TmpReg = MI.getOperand(0).getReg();
613 if (Opcode == ARM::tRestore) {
614 if (FrameReg == ARM::SP)
615 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
616 Offset, false, TII, *this, dl);
618 emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
622 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
626 MI.setDesc(TII.get(ARM::tLDR));
627 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
629 // Use [reg, reg] addrmode.
630 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
631 else // tLDR has an extra register operand.
632 MI.addOperand(MachineOperand::CreateReg(0, false));
633 } else if (Desc.mayStore()) {
634 VReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
635 assert (Value && "Frame index virtual allocated, but Value arg is NULL!");
639 if (Opcode == ARM::tSpill) {
640 if (FrameReg == ARM::SP)
641 emitThumbRegPlusImmInReg(MBB, II, VReg, FrameReg,
642 Offset, false, TII, *this, dl);
644 emitLoadConstPool(MBB, II, dl, VReg, 0, Offset);
648 emitThumbRegPlusImmediate(MBB, II, VReg, FrameReg, Offset, TII,
650 MI.setDesc(TII.get(ARM::tSTR));
651 MI.getOperand(i).ChangeToRegister(VReg, false, false, true);
652 if (UseRR) // Use [reg, reg] addrmode.
653 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
654 else // tSTR has an extra register operand.
655 MI.addOperand(MachineOperand::CreateReg(0, false));
657 assert(false && "Unexpected opcode!");
659 // Add predicate back if it's needed.
660 if (MI.getDesc().isPredicable()) {
661 MachineInstrBuilder MIB(&MI);
667 void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const {
668 MachineBasicBlock &MBB = MF.front();
669 MachineBasicBlock::iterator MBBI = MBB.begin();
670 MachineFrameInfo *MFI = MF.getFrameInfo();
671 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
672 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
673 unsigned NumBytes = MFI->getStackSize();
674 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
675 DebugLoc dl = (MBBI != MBB.end() ?
676 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
678 // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
679 NumBytes = (NumBytes + 3) & ~3;
680 MFI->setStackSize(NumBytes);
682 // Determine the sizes of each callee-save spill areas and record which frame
683 // belongs to which callee-save spill areas.
684 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
685 int FramePtrSpillFI = 0;
688 emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
690 if (!AFI->hasStackFrame()) {
692 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
696 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
697 unsigned Reg = CSI[i].getReg();
698 int FI = CSI[i].getFrameIdx();
706 FramePtrSpillFI = FI;
707 AFI->addGPRCalleeSavedArea1Frame(FI);
715 FramePtrSpillFI = FI;
716 if (STI.isTargetDarwin()) {
717 AFI->addGPRCalleeSavedArea2Frame(FI);
720 AFI->addGPRCalleeSavedArea1Frame(FI);
725 AFI->addDPRCalleeSavedAreaFrame(FI);
730 if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
732 if (MBBI != MBB.end())
733 dl = MBBI->getDebugLoc();
736 // Darwin ABI requires FP to point to the stack slot that contains the
738 if (STI.isTargetDarwin() || hasFP(MF)) {
739 BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
740 .addFrameIndex(FramePtrSpillFI).addImm(0);
743 // Determine starting offsets of spill areas.
744 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
745 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
746 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
747 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
748 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
749 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
750 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
752 NumBytes = DPRCSOffset;
754 // Insert it after all the callee-save spills.
755 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
758 if (STI.isTargetELF() && hasFP(MF)) {
759 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
760 AFI->getFramePtrSpillOffset());
763 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
764 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
765 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
768 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
769 for (unsigned i = 0; CSRegs[i]; ++i)
770 if (Reg == CSRegs[i])
775 static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
776 return (MI->getOpcode() == ARM::tRestore &&
777 MI->getOperand(1).isFI() &&
778 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
781 void Thumb1RegisterInfo::emitEpilogue(MachineFunction &MF,
782 MachineBasicBlock &MBB) const {
783 MachineBasicBlock::iterator MBBI = prior(MBB.end());
784 assert((MBBI->getOpcode() == ARM::tBX_RET ||
785 MBBI->getOpcode() == ARM::tPOP_RET) &&
786 "Can only insert epilog into returning blocks");
787 DebugLoc dl = MBBI->getDebugLoc();
788 MachineFrameInfo *MFI = MF.getFrameInfo();
789 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
790 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
791 int NumBytes = (int)MFI->getStackSize();
793 if (!AFI->hasStackFrame()) {
795 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
797 // Unwind MBBI to point to first LDR / FLDD.
798 const unsigned *CSRegs = getCalleeSavedRegs();
799 if (MBBI != MBB.begin()) {
802 while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
803 if (!isCSRestore(MBBI, CSRegs))
807 // Move SP to start of FP callee save spill area.
808 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
809 AFI->getGPRCalleeSavedArea2Size() +
810 AFI->getDPRCalleeSavedAreaSize());
813 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
814 // Reset SP based on frame pointer only if the stack frame extends beyond
815 // frame pointer stack slot or target is ELF and the function has FP.
817 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
820 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
823 if (MBBI->getOpcode() == ARM::tBX_RET &&
824 &MBB.front() != MBBI &&
825 prior(MBBI)->getOpcode() == ARM::tPOP) {
826 MachineBasicBlock::iterator PMBBI = prior(MBBI);
827 emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
829 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
834 // Epilogue for vararg functions: pop LR to R3 and branch off it.
835 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
836 .addReg(0) // No write back.
837 .addReg(ARM::R3, RegState::Define);
839 emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
841 BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg))
842 .addReg(ARM::R3, RegState::Kill);