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
13 //===----------------------------------------------------------------------===//
16 #include "ARMAddressingModes.h"
17 #include "ARMBaseInstrInfo.h"
18 #include "ARMMachineFunctionInfo.h"
19 #include "ARMSubtarget.h"
20 #include "Thumb1InstrInfo.h"
21 #include "Thumb1RegisterInfo.h"
22 #include "llvm/Constants.h"
23 #include "llvm/DerivedTypes.h"
24 #include "llvm/Function.h"
25 #include "llvm/LLVMContext.h"
26 #include "llvm/CodeGen/MachineConstantPool.h"
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineFunction.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineLocation.h"
31 #include "llvm/CodeGen/MachineRegisterInfo.h"
32 #include "llvm/Target/TargetFrameInfo.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/ADT/BitVector.h"
35 #include "llvm/ADT/SmallVector.h"
36 #include "llvm/Support/CommandLine.h"
37 #include "llvm/Support/ErrorHandling.h"
38 #include "llvm/Support/raw_ostream.h"
41 extern cl::opt<bool> ReuseFrameIndexVals;
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, unsigned SubIdx,
55 ARMCC::CondCodes Pred,
56 unsigned PredReg) const {
57 MachineFunction &MF = *MBB.getParent();
58 MachineConstantPool *ConstantPool = MF.getConstantPool();
59 Constant *C = ConstantInt::get(
60 Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
61 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
63 BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRcp))
64 .addReg(DestReg, getDefRegState(true), SubIdx)
65 .addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg);
68 const TargetRegisterClass*
69 Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, EVT VT) const {
70 if (isARMLowRegister(Reg))
71 return ARM::tGPRRegisterClass;
75 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
76 case ARM::R12: case ARM::SP: case ARM::LR: case ARM::PC:
77 return ARM::GPRRegisterClass;
80 return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
83 bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
84 const MachineFrameInfo *FFI = MF.getFrameInfo();
85 unsigned CFSize = FFI->getMaxCallFrameSize();
86 // It's not always a good idea to include the call frame as part of the
87 // stack frame. ARM (especially Thumb) has small immediate offset to
88 // address the stack frame. So a large call frame can cause poor codegen
89 // and may even makes it impossible to scavenge a register.
90 if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
93 return !MF.getFrameInfo()->hasVarSizedObjects();
97 /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
98 /// a destreg = basereg + immediate in Thumb code. Materialize the immediate
99 /// in a register using mov / mvn sequences or load the immediate from a
102 void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
103 MachineBasicBlock::iterator &MBBI,
104 unsigned DestReg, unsigned BaseReg,
105 int NumBytes, bool CanChangeCC,
106 const TargetInstrInfo &TII,
107 const Thumb1RegisterInfo& MRI,
109 MachineFunction &MF = *MBB.getParent();
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!");
124 LdReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
127 if (NumBytes <= 255 && NumBytes >= 0)
128 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
130 else if (NumBytes < 0 && NumBytes >= -255) {
131 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
133 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg))
134 .addReg(LdReg, RegState::Kill);
136 MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes);
139 int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
140 MachineInstrBuilder MIB =
141 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
142 if (Opc != ARM::tADDhirr)
143 MIB = AddDefaultT1CC(MIB);
144 if (DestReg == ARM::SP || isSub)
145 MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
147 MIB.addReg(LdReg).addReg(BaseReg, 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 bool NeedPred = false;
197 if (DestReg == BaseReg && BaseReg == ARM::SP) {
198 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
201 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
203 } else if (!isSub && BaseReg == ARM::SP) {
206 // r1 = add sp, 100 * 4
210 ExtraOpc = ARM::tADDi3;
219 if (DestReg != BaseReg)
222 if (DestReg == ARM::SP) {
223 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
224 assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
228 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
230 NeedPred = NeedCC = true;
235 unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
236 unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
237 if (NumMIs > Threshold) {
238 // This will expand into too many instructions. Load the immediate from a
240 emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
246 if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
247 // If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
248 unsigned Chunk = (1 << 3) - 1;
249 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
251 const TargetInstrDesc &TID = TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3);
252 const MachineInstrBuilder MIB =
253 AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg));
254 AddDefaultPred(MIB.addReg(BaseReg, RegState::Kill).addImm(ThisVal));
256 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
257 .addReg(BaseReg, RegState::Kill);
262 unsigned Chunk = ((1 << NumBits) - 1) * Scale;
264 unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
267 // Build the new tADD / tSUB.
269 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
271 MIB = AddDefaultT1CC(MIB);
272 MIB .addReg(DestReg).addImm(ThisVal);
274 MIB = AddDefaultPred(MIB);
277 bool isKill = BaseReg != ARM::SP;
278 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
280 MIB = AddDefaultT1CC(MIB);
281 MIB.addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
283 MIB = AddDefaultPred(MIB);
286 if (Opc == ARM::tADDrSPi) {
292 Chunk = ((1 << NumBits) - 1) * Scale;
293 Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
294 NeedPred = NeedCC = isTwoAddr = true;
300 const TargetInstrDesc &TID = TII.get(ExtraOpc);
301 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
302 .addReg(DestReg, RegState::Kill)
303 .addImm(((unsigned)NumBytes) & 3));
307 static void emitSPUpdate(MachineBasicBlock &MBB,
308 MachineBasicBlock::iterator &MBBI,
309 const TargetInstrInfo &TII, DebugLoc dl,
310 const Thumb1RegisterInfo &MRI,
312 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
316 void Thumb1RegisterInfo::
317 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
318 MachineBasicBlock::iterator I) const {
319 if (!hasReservedCallFrame(MF)) {
320 // If we have alloca, convert as follows:
321 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
322 // ADJCALLSTACKUP -> add, sp, sp, amount
323 MachineInstr *Old = I;
324 DebugLoc dl = Old->getDebugLoc();
325 unsigned Amount = Old->getOperand(0).getImm();
327 // We need to keep the stack aligned properly. To do this, we round the
328 // amount of space needed for the outgoing arguments up to the next
329 // alignment boundary.
330 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
331 Amount = (Amount+Align-1)/Align*Align;
333 // Replace the pseudo instruction with a new instruction...
334 unsigned Opc = Old->getOpcode();
335 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
336 emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
338 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
339 emitSPUpdate(MBB, I, TII, dl, *this, Amount);
346 /// emitThumbConstant - Emit a series of instructions to materialize a
348 static void emitThumbConstant(MachineBasicBlock &MBB,
349 MachineBasicBlock::iterator &MBBI,
350 unsigned DestReg, int Imm,
351 const TargetInstrInfo &TII,
352 const Thumb1RegisterInfo& MRI,
354 bool isSub = Imm < 0;
355 if (isSub) Imm = -Imm;
357 int Chunk = (1 << 8) - 1;
358 int ThisVal = (Imm > Chunk) ? Chunk : Imm;
360 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8),
364 emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
366 const TargetInstrDesc &TID = TII.get(ARM::tRSB);
367 AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
368 .addReg(DestReg, RegState::Kill));
372 static void removeOperands(MachineInstr &MI, unsigned i) {
374 for (unsigned e = MI.getNumOperands(); i != e; ++i)
375 MI.RemoveOperand(Op);
378 int Thumb1RegisterInfo::
379 rewriteFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
380 unsigned FrameReg, int Offset,
381 unsigned MOVOpc, unsigned ADDriOpc, unsigned SUBriOpc) const
383 // if/when eliminateFrameIndex() conforms with ARMBaseRegisterInfo
384 // version then can pull out Thumb1 specific parts here
388 /// saveScavengerRegister - Spill the register so it can be used by the
389 /// register scavenger. Return true.
391 Thumb1RegisterInfo::saveScavengerRegister(MachineBasicBlock &MBB,
392 MachineBasicBlock::iterator I,
393 MachineBasicBlock::iterator &UseMI,
394 const TargetRegisterClass *RC,
395 unsigned Reg) const {
396 // Thumb1 can't use the emergency spill slot on the stack because
397 // ldr/str immediate offsets must be positive, and if we're referencing
398 // off the frame pointer (if, for example, there are alloca() calls in
399 // the function, the offset will be negative. Use R12 instead since that's
400 // a call clobbered register that we know won't be used in Thumb1 mode.
401 DebugLoc DL = DebugLoc::getUnknownLoc();
402 BuildMI(MBB, I, DL, TII.get(ARM::tMOVtgpr2gpr)).
403 addReg(ARM::R12, RegState::Define).addReg(Reg, RegState::Kill);
405 // The UseMI is where we would like to restore the register. If there's
406 // interference with R12 before then, however, we'll need to restore it
407 // before that instead and adjust the UseMI.
409 for (MachineBasicBlock::iterator II = I; !done && II != UseMI ; ++II) {
410 // If this instruction affects R12, adjust our restore point.
411 for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
412 const MachineOperand &MO = II->getOperand(i);
413 if (!MO.isReg() || MO.isUndef() || !MO.getReg() ||
414 TargetRegisterInfo::isVirtualRegister(MO.getReg()))
416 if (MO.getReg() == ARM::R12) {
423 // Restore the register from R12
424 BuildMI(MBB, UseMI, DL, TII.get(ARM::tMOVgpr2tgpr)).
425 addReg(Reg, RegState::Define).addReg(ARM::R12, RegState::Kill);
431 Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
432 int SPAdj, int *Value,
433 RegScavenger *RS) const{
436 MachineInstr &MI = *II;
437 MachineBasicBlock &MBB = *MI.getParent();
438 MachineFunction &MF = *MBB.getParent();
439 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
440 DebugLoc dl = MI.getDebugLoc();
442 while (!MI.getOperand(i).isFI()) {
444 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
447 unsigned FrameReg = ARM::SP;
448 int FrameIndex = MI.getOperand(i).getIndex();
449 int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
450 MF.getFrameInfo()->getStackSize() + SPAdj;
452 if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
453 Offset -= AFI->getGPRCalleeSavedArea1Offset();
454 else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
455 Offset -= AFI->getGPRCalleeSavedArea2Offset();
456 else if (MF.getFrameInfo()->hasVarSizedObjects()) {
457 assert(SPAdj == 0 && hasFP(MF) && "Unexpected");
458 // There are alloca()'s in this function, must reference off the frame
460 FrameReg = getFrameRegister(MF);
461 Offset -= AFI->getFramePtrSpillOffset();
464 unsigned Opcode = MI.getOpcode();
465 const TargetInstrDesc &Desc = MI.getDesc();
466 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
468 if (Opcode == ARM::tADDrSPi) {
469 Offset += MI.getOperand(i+1).getImm();
471 // Can't use tADDrSPi if it's based off the frame pointer.
472 unsigned NumBits = 0;
474 if (FrameReg != ARM::SP) {
475 Opcode = ARM::tADDi3;
476 MI.setDesc(TII.get(Opcode));
481 assert((Offset & 3) == 0 &&
482 "Thumb add/sub sp, #imm immediate must be multiple of 4!");
486 if (Offset == 0 && getInstrPredicate(&MI, PredReg) == ARMCC::AL) {
487 // Turn it into a move.
488 MI.setDesc(TII.get(ARM::tMOVgpr2tgpr));
489 MI.getOperand(i).ChangeToRegister(FrameReg, false);
490 // Remove offset and remaining explicit predicate operands.
491 do MI.RemoveOperand(i+1);
492 while (MI.getNumOperands() > i+1 &&
493 (!MI.getOperand(i+1).isReg() || !MI.getOperand(i+1).isImm()));
497 // Common case: small offset, fits into instruction.
498 unsigned Mask = (1 << NumBits) - 1;
499 if (((Offset / Scale) & ~Mask) == 0) {
500 // Replace the FrameIndex with sp / fp
501 if (Opcode == ARM::tADDi3) {
502 removeOperands(MI, i);
503 MachineInstrBuilder MIB(&MI);
504 AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg)
505 .addImm(Offset / Scale));
507 MI.getOperand(i).ChangeToRegister(FrameReg, false);
508 MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
513 unsigned DestReg = MI.getOperand(0).getReg();
514 unsigned Bytes = (Offset > 0) ? Offset : -Offset;
515 unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
516 // MI would expand into a large number of instructions. Don't try to
517 // simplify the immediate.
519 emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
526 // Translate r0 = add sp, imm to
527 // r0 = add sp, 255*4
528 // r0 = add r0, (imm - 255*4)
529 if (Opcode == ARM::tADDi3) {
530 removeOperands(MI, i);
531 MachineInstrBuilder MIB(&MI);
532 AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg).addImm(Mask));
534 MI.getOperand(i).ChangeToRegister(FrameReg, false);
535 MI.getOperand(i+1).ChangeToImmediate(Mask);
537 Offset = (Offset - Mask * Scale);
538 MachineBasicBlock::iterator NII = llvm::next(II);
539 emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
542 // Translate r0 = add sp, -imm to
543 // r0 = -imm (this is then translated into a series of instructons)
545 emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
547 MI.setDesc(TII.get(ARM::tADDhirr));
548 MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
549 MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
550 if (Opcode == ARM::tADDi3) {
551 MachineInstrBuilder MIB(&MI);
559 unsigned NumBits = 0;
562 case ARMII::AddrModeT1_s: {
564 InstrOffs = MI.getOperand(ImmIdx).getImm();
565 NumBits = (FrameReg == ARM::SP) ? 8 : 5;
570 llvm_unreachable("Unsupported addressing mode!");
574 Offset += InstrOffs * Scale;
575 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
577 // Common case: small offset, fits into instruction.
578 MachineOperand &ImmOp = MI.getOperand(ImmIdx);
579 int ImmedOffset = Offset / Scale;
580 unsigned Mask = (1 << NumBits) - 1;
581 if ((unsigned)Offset <= Mask * Scale) {
582 // Replace the FrameIndex with sp
583 MI.getOperand(i).ChangeToRegister(FrameReg, false);
584 ImmOp.ChangeToImmediate(ImmedOffset);
588 bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
589 if (AddrMode == ARMII::AddrModeT1_s) {
590 // Thumb tLDRspi, tSTRspi. These will change to instructions that use
591 // a different base register.
593 Mask = (1 << NumBits) - 1;
595 // If this is a thumb spill / restore, we will be using a constpool load to
596 // materialize the offset.
597 if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
598 ImmOp.ChangeToImmediate(0);
600 // Otherwise, it didn't fit. Pull in what we can to simplify the immed.
601 ImmedOffset = ImmedOffset & Mask;
602 ImmOp.ChangeToImmediate(ImmedOffset);
603 Offset &= ~(Mask*Scale);
607 // If we get here, the immediate doesn't fit into the instruction. We folded
608 // as much as possible above, handle the rest, providing a register that is
610 assert(Offset && "This code isn't needed if offset already handled!");
612 // Remove predicate first.
613 int PIdx = MI.findFirstPredOperandIdx();
615 removeOperands(MI, PIdx);
617 if (Desc.mayLoad()) {
618 // Use the destination register to materialize sp + offset.
619 unsigned TmpReg = MI.getOperand(0).getReg();
621 if (Opcode == ARM::tRestore) {
622 if (FrameReg == ARM::SP)
623 emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
624 Offset, false, TII, *this, dl);
626 emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
630 emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
634 MI.setDesc(TII.get(ARM::tLDR));
635 MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
637 // Use [reg, reg] addrmode.
638 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
639 else // tLDR has an extra register operand.
640 MI.addOperand(MachineOperand::CreateReg(0, false));
641 } else if (Desc.mayStore()) {
642 VReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
643 assert (Value && "Frame index virtual allocated, but Value arg is NULL!");
646 bool TrackVReg = FrameReg == ARM::SP;
648 if (Opcode == ARM::tSpill) {
649 if (FrameReg == ARM::SP)
650 emitThumbRegPlusImmInReg(MBB, II, VReg, FrameReg,
651 Offset, false, TII, *this, dl);
653 emitLoadConstPool(MBB, II, dl, VReg, 0, Offset);
658 emitThumbRegPlusImmediate(MBB, II, VReg, FrameReg, Offset, TII,
660 MI.setDesc(TII.get(ARM::tSTR));
661 MI.getOperand(i).ChangeToRegister(VReg, false, false, true);
662 if (UseRR) // Use [reg, reg] addrmode.
663 MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
664 else // tSTR has an extra register operand.
665 MI.addOperand(MachineOperand::CreateReg(0, false));
666 if (!ReuseFrameIndexVals || !TrackVReg)
669 assert(false && "Unexpected opcode!");
671 // Add predicate back if it's needed.
672 if (MI.getDesc().isPredicable()) {
673 MachineInstrBuilder MIB(&MI);
679 void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const {
680 MachineBasicBlock &MBB = MF.front();
681 MachineBasicBlock::iterator MBBI = MBB.begin();
682 MachineFrameInfo *MFI = MF.getFrameInfo();
683 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
684 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
685 unsigned NumBytes = MFI->getStackSize();
686 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
687 DebugLoc dl = (MBBI != MBB.end() ?
688 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
690 // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
691 NumBytes = (NumBytes + 3) & ~3;
692 MFI->setStackSize(NumBytes);
694 // Determine the sizes of each callee-save spill areas and record which frame
695 // belongs to which callee-save spill areas.
696 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
697 int FramePtrSpillFI = 0;
700 emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
702 if (!AFI->hasStackFrame()) {
704 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
708 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
709 unsigned Reg = CSI[i].getReg();
710 int FI = CSI[i].getFrameIdx();
718 FramePtrSpillFI = FI;
719 AFI->addGPRCalleeSavedArea1Frame(FI);
727 FramePtrSpillFI = FI;
728 if (STI.isTargetDarwin()) {
729 AFI->addGPRCalleeSavedArea2Frame(FI);
732 AFI->addGPRCalleeSavedArea1Frame(FI);
737 AFI->addDPRCalleeSavedAreaFrame(FI);
742 if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
744 if (MBBI != MBB.end())
745 dl = MBBI->getDebugLoc();
748 // Darwin ABI requires FP to point to the stack slot that contains the
750 if (STI.isTargetDarwin() || hasFP(MF)) {
751 BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
752 .addFrameIndex(FramePtrSpillFI).addImm(0);
755 // Determine starting offsets of spill areas.
756 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
757 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
758 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
759 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
760 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
761 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
762 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
764 NumBytes = DPRCSOffset;
766 // Insert it after all the callee-save spills.
767 emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
770 if (STI.isTargetELF() && hasFP(MF)) {
771 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
772 AFI->getFramePtrSpillOffset());
775 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
776 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
777 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
780 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
781 for (unsigned i = 0; CSRegs[i]; ++i)
782 if (Reg == CSRegs[i])
787 static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
788 if (MI->getOpcode() == ARM::tRestore &&
789 MI->getOperand(1).isFI() &&
790 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs))
792 else if (MI->getOpcode() == ARM::tPOP) {
793 // The first three operands are predicates and such. The last two are
794 // imp-def and imp-use of SP. Check everything in between.
795 for (int i = 3, e = MI->getNumOperands() - 2; i != e; ++i)
796 if (!isCalleeSavedRegister(MI->getOperand(i).getReg(), CSRegs))
803 void Thumb1RegisterInfo::emitEpilogue(MachineFunction &MF,
804 MachineBasicBlock &MBB) const {
805 MachineBasicBlock::iterator MBBI = prior(MBB.end());
806 assert((MBBI->getOpcode() == ARM::tBX_RET ||
807 MBBI->getOpcode() == ARM::tPOP_RET) &&
808 "Can only insert epilog into returning blocks");
809 DebugLoc dl = MBBI->getDebugLoc();
810 MachineFrameInfo *MFI = MF.getFrameInfo();
811 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
812 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
813 int NumBytes = (int)MFI->getStackSize();
814 const unsigned *CSRegs = getCalleeSavedRegs();
816 if (!AFI->hasStackFrame()) {
818 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
820 // Unwind MBBI to point to first LDR / VLDRD.
821 if (MBBI != MBB.begin()) {
824 while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
825 if (!isCSRestore(MBBI, CSRegs))
829 // Move SP to start of FP callee save spill area.
830 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
831 AFI->getGPRCalleeSavedArea2Size() +
832 AFI->getDPRCalleeSavedAreaSize());
835 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
836 // Reset SP based on frame pointer only if the stack frame extends beyond
837 // frame pointer stack slot or target is ELF and the function has FP.
839 emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
842 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
845 if (MBBI->getOpcode() == ARM::tBX_RET &&
846 &MBB.front() != MBBI &&
847 prior(MBBI)->getOpcode() == ARM::tPOP) {
848 MachineBasicBlock::iterator PMBBI = prior(MBBI);
849 emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
851 emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
856 // Move back past the callee-saved register restoration
857 while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs))
859 // Epilogue for vararg functions: pop LR to R3 and branch off it.
860 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
861 .addReg(0) // No write back.
862 .addReg(ARM::R3, RegState::Define);
864 emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
866 BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg))
867 .addReg(ARM::R3, RegState::Kill);
868 // erase the old tBX_RET instruction