1 //===- ARMBaseRegisterInfo.cpp - ARM 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 base ARM implementation of TargetRegisterInfo class.
12 //===----------------------------------------------------------------------===//
15 #include "ARMAddressingModes.h"
16 #include "ARMBaseInstrInfo.h"
17 #include "ARMBaseRegisterInfo.h"
18 #include "ARMInstrInfo.h"
19 #include "ARMMachineFunctionInfo.h"
20 #include "ARMSubtarget.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/CodeGen/RegisterScavenging.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include "llvm/Target/TargetFrameInfo.h"
36 #include "llvm/Target/TargetMachine.h"
37 #include "llvm/Target/TargetOptions.h"
38 #include "llvm/ADT/BitVector.h"
39 #include "llvm/ADT/SmallVector.h"
40 #include "llvm/Support/CommandLine.h"
44 ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
45 cl::desc("Reuse repeated frame index values"));
50 unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
58 llvm_unreachable("Unknown ARM register!");
59 case R0: case D0: case Q0: return 0;
60 case R1: case D1: case Q1: return 1;
61 case R2: case D2: case Q2: return 2;
62 case R3: case D3: case Q3: return 3;
63 case R4: case D4: case Q4: return 4;
64 case R5: case D5: case Q5: return 5;
65 case R6: case D6: case Q6: return 6;
66 case R7: case D7: case Q7: return 7;
67 case R8: case D8: case Q8: return 8;
68 case R9: case D9: case Q9: return 9;
69 case R10: case D10: case Q10: return 10;
70 case R11: case D11: case Q11: return 11;
71 case R12: case D12: case Q12: return 12;
72 case SP: case D13: case Q13: return 13;
73 case LR: case D14: case Q14: return 14;
74 case PC: case D15: case Q15: return 15;
93 case S0: case S1: case S2: case S3:
94 case S4: case S5: case S6: case S7:
95 case S8: case S9: case S10: case S11:
96 case S12: case S13: case S14: case S15:
97 case S16: case S17: case S18: case S19:
98 case S20: case S21: case S22: case S23:
99 case S24: case S25: case S26: case S27:
100 case S28: case S29: case S30: case S31: {
104 default: return 0; // Avoid compile time warning.
142 ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
143 const ARMSubtarget &sti)
144 : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
146 FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
150 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
151 static const unsigned CalleeSavedRegs[] = {
152 ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
153 ARM::R7, ARM::R6, ARM::R5, ARM::R4,
155 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
156 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
160 static const unsigned DarwinCalleeSavedRegs[] = {
161 // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
163 ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
164 ARM::R11, ARM::R10, ARM::R8,
166 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
167 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
170 return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
173 const TargetRegisterClass* const *
174 ARMBaseRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
175 static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
176 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
177 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
178 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
180 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
181 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
185 static const TargetRegisterClass * const ThumbCalleeSavedRegClasses[] = {
186 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
187 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::tGPRRegClass,
188 &ARM::tGPRRegClass,&ARM::tGPRRegClass,&ARM::tGPRRegClass,
190 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
191 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
195 static const TargetRegisterClass * const DarwinCalleeSavedRegClasses[] = {
196 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
197 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
198 &ARM::GPRRegClass, &ARM::GPRRegClass,
200 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
201 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
205 static const TargetRegisterClass * const DarwinThumbCalleeSavedRegClasses[] ={
206 &ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass,
207 &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::GPRRegClass,
208 &ARM::GPRRegClass, &ARM::GPRRegClass,
210 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
211 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
215 if (STI.isThumb1Only()) {
216 return STI.isTargetDarwin()
217 ? DarwinThumbCalleeSavedRegClasses : ThumbCalleeSavedRegClasses;
219 return STI.isTargetDarwin()
220 ? DarwinCalleeSavedRegClasses : CalleeSavedRegClasses;
223 BitVector ARMBaseRegisterInfo::
224 getReservedRegs(const MachineFunction &MF) const {
225 // FIXME: avoid re-calculating this everytime.
226 BitVector Reserved(getNumRegs());
227 Reserved.set(ARM::SP);
228 Reserved.set(ARM::PC);
229 if (STI.isTargetDarwin() || hasFP(MF))
230 Reserved.set(FramePtr);
231 // Some targets reserve R9.
232 if (STI.isR9Reserved())
233 Reserved.set(ARM::R9);
237 bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
238 unsigned Reg) const {
246 if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
250 return STI.isR9Reserved();
256 const TargetRegisterClass *
257 ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
258 const TargetRegisterClass *B,
259 unsigned SubIdx) const {
267 if (A->getSize() == 8) {
268 if (B == &ARM::SPR_8RegClass)
269 return &ARM::DPR_8RegClass;
270 assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
271 if (A == &ARM::DPR_8RegClass)
273 return &ARM::DPR_VFP2RegClass;
276 if (A->getSize() == 16) {
277 if (B == &ARM::SPR_8RegClass)
278 return &ARM::QPR_8RegClass;
279 return &ARM::QPR_VFP2RegClass;
282 assert(A->getSize() == 32 && "Expecting a QQ register class!");
283 if (B == &ARM::SPR_8RegClass)
284 return &ARM::QQPR_8RegClass;
285 return &ARM::QQPR_VFP2RegClass;
292 if (A->getSize() == 16) {
293 if (B == &ARM::DPR_VFP2RegClass)
294 return &ARM::QPR_VFP2RegClass;
295 if (B == &ARM::DPR_8RegClass)
296 return &ARM::QPR_8RegClass;
300 assert(A->getSize() == 32 && "Expecting a QQ register class!");
301 if (B == &ARM::DPR_VFP2RegClass)
302 return &ARM::QQPR_VFP2RegClass;
303 if (B == &ARM::DPR_8RegClass)
304 return &ARM::QQPR_8RegClass;
310 assert(A->getSize() == 32 && "Expecting a QQ register class!");
311 if (B == &ARM::QPR_VFP2RegClass)
312 return &ARM::QQPR_VFP2RegClass;
313 if (B == &ARM::QPR_8RegClass)
314 return &ARM::QQPR_8RegClass;
321 const TargetRegisterClass *
322 ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
323 return ARM::GPRRegisterClass;
326 /// getAllocationOrder - Returns the register allocation order for a specified
327 /// register class in the form of a pair of TargetRegisterClass iterators.
328 std::pair<TargetRegisterClass::iterator,TargetRegisterClass::iterator>
329 ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
330 unsigned HintType, unsigned HintReg,
331 const MachineFunction &MF) const {
332 // Alternative register allocation orders when favoring even / odd registers
333 // of register pairs.
335 // No FP, R9 is available.
336 static const unsigned GPREven1[] = {
337 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
338 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
341 static const unsigned GPROdd1[] = {
342 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
343 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
347 // FP is R7, R9 is available.
348 static const unsigned GPREven2[] = {
349 ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
350 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
353 static const unsigned GPROdd2[] = {
354 ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
355 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
359 // FP is R11, R9 is available.
360 static const unsigned GPREven3[] = {
361 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
362 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
365 static const unsigned GPROdd3[] = {
366 ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
367 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
371 // No FP, R9 is not available.
372 static const unsigned GPREven4[] = {
373 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
374 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
377 static const unsigned GPROdd4[] = {
378 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
379 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
383 // FP is R7, R9 is not available.
384 static const unsigned GPREven5[] = {
385 ARM::R0, ARM::R2, ARM::R4, ARM::R10,
386 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
389 static const unsigned GPROdd5[] = {
390 ARM::R1, ARM::R3, ARM::R5, ARM::R11,
391 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
395 // FP is R11, R9 is not available.
396 static const unsigned GPREven6[] = {
397 ARM::R0, ARM::R2, ARM::R4, ARM::R6,
398 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
400 static const unsigned GPROdd6[] = {
401 ARM::R1, ARM::R3, ARM::R5, ARM::R7,
402 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
406 if (HintType == ARMRI::RegPairEven) {
407 if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
408 // It's no longer possible to fulfill this hint. Return the default
410 return std::make_pair(RC->allocation_order_begin(MF),
411 RC->allocation_order_end(MF));
413 if (!STI.isTargetDarwin() && !hasFP(MF)) {
414 if (!STI.isR9Reserved())
415 return std::make_pair(GPREven1,
416 GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
418 return std::make_pair(GPREven4,
419 GPREven4 + (sizeof(GPREven4)/sizeof(unsigned)));
420 } else if (FramePtr == ARM::R7) {
421 if (!STI.isR9Reserved())
422 return std::make_pair(GPREven2,
423 GPREven2 + (sizeof(GPREven2)/sizeof(unsigned)));
425 return std::make_pair(GPREven5,
426 GPREven5 + (sizeof(GPREven5)/sizeof(unsigned)));
427 } else { // FramePtr == ARM::R11
428 if (!STI.isR9Reserved())
429 return std::make_pair(GPREven3,
430 GPREven3 + (sizeof(GPREven3)/sizeof(unsigned)));
432 return std::make_pair(GPREven6,
433 GPREven6 + (sizeof(GPREven6)/sizeof(unsigned)));
435 } else if (HintType == ARMRI::RegPairOdd) {
436 if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
437 // It's no longer possible to fulfill this hint. Return the default
439 return std::make_pair(RC->allocation_order_begin(MF),
440 RC->allocation_order_end(MF));
442 if (!STI.isTargetDarwin() && !hasFP(MF)) {
443 if (!STI.isR9Reserved())
444 return std::make_pair(GPROdd1,
445 GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
447 return std::make_pair(GPROdd4,
448 GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned)));
449 } else if (FramePtr == ARM::R7) {
450 if (!STI.isR9Reserved())
451 return std::make_pair(GPROdd2,
452 GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned)));
454 return std::make_pair(GPROdd5,
455 GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned)));
456 } else { // FramePtr == ARM::R11
457 if (!STI.isR9Reserved())
458 return std::make_pair(GPROdd3,
459 GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned)));
461 return std::make_pair(GPROdd6,
462 GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned)));
465 return std::make_pair(RC->allocation_order_begin(MF),
466 RC->allocation_order_end(MF));
469 /// ResolveRegAllocHint - Resolves the specified register allocation hint
470 /// to a physical register. Returns the physical register if it is successful.
472 ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
473 const MachineFunction &MF) const {
474 if (Reg == 0 || !isPhysicalRegister(Reg))
478 else if (Type == (unsigned)ARMRI::RegPairOdd)
480 return getRegisterPairOdd(Reg, MF);
481 else if (Type == (unsigned)ARMRI::RegPairEven)
483 return getRegisterPairEven(Reg, MF);
488 ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
489 MachineFunction &MF) const {
490 MachineRegisterInfo *MRI = &MF.getRegInfo();
491 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
492 if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
493 Hint.first == (unsigned)ARMRI::RegPairEven) &&
494 Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) {
495 // If 'Reg' is one of the even / odd register pair and it's now changed
496 // (e.g. coalesced) into a different register. The other register of the
497 // pair allocation hint must be updated to reflect the relationship
499 unsigned OtherReg = Hint.second;
500 Hint = MRI->getRegAllocationHint(OtherReg);
501 if (Hint.second == Reg)
502 // Make sure the pair has not already divorced.
503 MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
507 /// hasFP - Return true if the specified function should have a dedicated frame
508 /// pointer register. This is true if the function has variable sized allocas
509 /// or if frame pointer elimination is disabled.
511 bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
512 const MachineFrameInfo *MFI = MF.getFrameInfo();
513 return ((DisableFramePointerElim(MF) && MFI->hasCalls())||
514 needsStackRealignment(MF) ||
515 MFI->hasVarSizedObjects() ||
516 MFI->isFrameAddressTaken());
519 bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
520 const MachineFrameInfo *MFI = MF.getFrameInfo();
521 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
522 return (RealignStack &&
523 !AFI->isThumb1OnlyFunction() &&
524 !MFI->hasVarSizedObjects());
527 bool ARMBaseRegisterInfo::
528 needsStackRealignment(const MachineFunction &MF) const {
529 const MachineFrameInfo *MFI = MF.getFrameInfo();
530 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
531 unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
532 return (RealignStack &&
533 !AFI->isThumb1OnlyFunction() &&
534 (MFI->getMaxAlignment() > StackAlign) &&
535 !MFI->hasVarSizedObjects());
538 bool ARMBaseRegisterInfo::
539 cannotEliminateFrame(const MachineFunction &MF) const {
540 const MachineFrameInfo *MFI = MF.getFrameInfo();
541 if (DisableFramePointerElim(MF) && MFI->hasCalls())
543 return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
544 || needsStackRealignment(MF);
547 /// estimateStackSize - Estimate and return the size of the frame.
548 static unsigned estimateStackSize(MachineFunction &MF) {
549 const MachineFrameInfo *FFI = MF.getFrameInfo();
551 for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
552 int FixedOff = -FFI->getObjectOffset(i);
553 if (FixedOff > Offset) Offset = FixedOff;
555 for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
556 if (FFI->isDeadObjectIndex(i))
558 Offset += FFI->getObjectSize(i);
559 unsigned Align = FFI->getObjectAlignment(i);
560 // Adjust to alignment boundary
561 Offset = (Offset+Align-1)/Align*Align;
563 return (unsigned)Offset;
566 /// estimateRSStackSizeLimit - Look at each instruction that references stack
567 /// frames and return the stack size limit beyond which some of these
568 /// instructions will require a scratch register during their expansion later.
570 ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
571 unsigned Limit = (1 << 12) - 1;
572 for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
573 for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
575 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
576 if (!I->getOperand(i).isFI()) continue;
578 const TargetInstrDesc &Desc = TII.get(I->getOpcode());
579 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
580 if (AddrMode == ARMII::AddrMode3 ||
581 AddrMode == ARMII::AddrModeT2_i8)
584 if (AddrMode == ARMII::AddrMode5 ||
585 AddrMode == ARMII::AddrModeT2_i8s4)
586 Limit = std::min(Limit, ((1U << 8) - 1) * 4);
588 if (AddrMode == ARMII::AddrModeT2_i12 && hasFP(MF))
589 // When the stack offset is negative, we will end up using
590 // the i8 instructions instead.
593 if (AddrMode == ARMII::AddrMode6)
595 break; // At most one FI per instruction
604 ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
605 RegScavenger *RS) const {
606 // This tells PEI to spill the FP as if it is any other callee-save register
607 // to take advantage the eliminateFrameIndex machinery. This also ensures it
608 // is spilled in the order specified by getCalleeSavedRegs() to make it easier
609 // to combine multiple loads / stores.
610 bool CanEliminateFrame = true;
611 bool CS1Spilled = false;
612 bool LRSpilled = false;
613 unsigned NumGPRSpills = 0;
614 SmallVector<unsigned, 4> UnspilledCS1GPRs;
615 SmallVector<unsigned, 4> UnspilledCS2GPRs;
616 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
618 // Spill R4 if Thumb2 function requires stack realignment - it will be used as
620 // FIXME: It will be better just to find spare register here.
621 if (needsStackRealignment(MF) &&
622 AFI->isThumb2Function())
623 MF.getRegInfo().setPhysRegUsed(ARM::R4);
625 // Spill LR if Thumb1 function uses variable length argument lists.
626 if (AFI->isThumb1OnlyFunction() && AFI->getVarArgsRegSaveSize() > 0)
627 MF.getRegInfo().setPhysRegUsed(ARM::LR);
629 // Don't spill FP if the frame can be eliminated. This is determined
630 // by scanning the callee-save registers to see if any is used.
631 const unsigned *CSRegs = getCalleeSavedRegs();
632 const TargetRegisterClass* const *CSRegClasses = getCalleeSavedRegClasses();
633 for (unsigned i = 0; CSRegs[i]; ++i) {
634 unsigned Reg = CSRegs[i];
635 bool Spilled = false;
636 if (MF.getRegInfo().isPhysRegUsed(Reg)) {
637 AFI->setCSRegisterIsSpilled(Reg);
639 CanEliminateFrame = false;
641 // Check alias registers too.
642 for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
643 if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
645 CanEliminateFrame = false;
650 if (CSRegClasses[i] == ARM::GPRRegisterClass ||
651 CSRegClasses[i] == ARM::tGPRRegisterClass) {
655 if (!STI.isTargetDarwin()) {
662 // Keep track if LR and any of R4, R5, R6, and R7 is spilled.
677 if (!STI.isTargetDarwin()) {
678 UnspilledCS1GPRs.push_back(Reg);
688 UnspilledCS1GPRs.push_back(Reg);
691 UnspilledCS2GPRs.push_back(Reg);
698 bool ForceLRSpill = false;
699 if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
700 unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
701 // Force LR to be spilled if the Thumb function size is > 2048. This enables
702 // use of BL to implement far jump. If it turns out that it's not needed
703 // then the branch fix up path will undo it.
704 if (FnSize >= (1 << 11)) {
705 CanEliminateFrame = false;
710 // If any of the stack slot references may be out of range of an immediate
711 // offset, make sure a register (or a spill slot) is available for the
712 // register scavenger. Note that if we're indexing off the frame pointer, the
713 // effective stack size is 4 bytes larger since the FP points to the stack
714 // slot of the previous FP.
715 bool BigStack = RS &&
716 estimateStackSize(MF) + (hasFP(MF) ? 4 : 0) >= estimateRSStackSizeLimit(MF);
718 bool ExtraCSSpill = false;
719 if (BigStack || !CanEliminateFrame || cannotEliminateFrame(MF)) {
720 AFI->setHasStackFrame(true);
722 // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
723 // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
724 if (!LRSpilled && CS1Spilled) {
725 MF.getRegInfo().setPhysRegUsed(ARM::LR);
726 AFI->setCSRegisterIsSpilled(ARM::LR);
728 UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
729 UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
730 ForceLRSpill = false;
734 // Darwin ABI requires FP to point to the stack slot that contains the
736 if (STI.isTargetDarwin() || hasFP(MF)) {
737 MF.getRegInfo().setPhysRegUsed(FramePtr);
741 // If stack and double are 8-byte aligned and we are spilling an odd number
742 // of GPRs. Spill one extra callee save GPR so we won't have to pad between
743 // the integer and double callee save areas.
744 unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
745 if (TargetAlign == 8 && (NumGPRSpills & 1)) {
746 if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
747 for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
748 unsigned Reg = UnspilledCS1GPRs[i];
749 // Don't spill high register if the function is thumb1
750 if (!AFI->isThumb1OnlyFunction() ||
751 isARMLowRegister(Reg) || Reg == ARM::LR) {
752 MF.getRegInfo().setPhysRegUsed(Reg);
753 AFI->setCSRegisterIsSpilled(Reg);
754 if (!isReservedReg(MF, Reg))
759 } else if (!UnspilledCS2GPRs.empty() &&
760 !AFI->isThumb1OnlyFunction()) {
761 unsigned Reg = UnspilledCS2GPRs.front();
762 MF.getRegInfo().setPhysRegUsed(Reg);
763 AFI->setCSRegisterIsSpilled(Reg);
764 if (!isReservedReg(MF, Reg))
769 // Estimate if we might need to scavenge a register at some point in order
770 // to materialize a stack offset. If so, either spill one additional
771 // callee-saved register or reserve a special spill slot to facilitate
772 // register scavenging. Thumb1 needs a spill slot for stack pointer
773 // adjustments also, even when the frame itself is small.
774 if (BigStack && !ExtraCSSpill) {
775 // If any non-reserved CS register isn't spilled, just spill one or two
776 // extra. That should take care of it!
777 unsigned NumExtras = TargetAlign / 4;
778 SmallVector<unsigned, 2> Extras;
779 while (NumExtras && !UnspilledCS1GPRs.empty()) {
780 unsigned Reg = UnspilledCS1GPRs.back();
781 UnspilledCS1GPRs.pop_back();
782 if (!isReservedReg(MF, Reg)) {
783 Extras.push_back(Reg);
787 // For non-Thumb1 functions, also check for hi-reg CS registers
788 if (!AFI->isThumb1OnlyFunction()) {
789 while (NumExtras && !UnspilledCS2GPRs.empty()) {
790 unsigned Reg = UnspilledCS2GPRs.back();
791 UnspilledCS2GPRs.pop_back();
792 if (!isReservedReg(MF, Reg)) {
793 Extras.push_back(Reg);
798 if (Extras.size() && NumExtras == 0) {
799 for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
800 MF.getRegInfo().setPhysRegUsed(Extras[i]);
801 AFI->setCSRegisterIsSpilled(Extras[i]);
803 } else if (!AFI->isThumb1OnlyFunction()) {
804 // note: Thumb1 functions spill to R12, not the stack. Reserve a slot
805 // closest to SP or frame pointer.
806 const TargetRegisterClass *RC = ARM::GPRRegisterClass;
807 MachineFrameInfo *MFI = MF.getFrameInfo();
808 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
816 MF.getRegInfo().setPhysRegUsed(ARM::LR);
817 AFI->setCSRegisterIsSpilled(ARM::LR);
818 AFI->setLRIsSpilledForFarJump(true);
822 unsigned ARMBaseRegisterInfo::getRARegister() const {
827 ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
828 if (STI.isTargetDarwin() || hasFP(MF))
834 ARMBaseRegisterInfo::getFrameIndexReference(const MachineFunction &MF, int FI,
835 unsigned &FrameReg) const {
836 const MachineFrameInfo *MFI = MF.getFrameInfo();
837 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
838 int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize();
839 bool isFixed = MFI->isFixedObjectIndex(FI);
842 if (AFI->isGPRCalleeSavedArea1Frame(FI))
843 Offset -= AFI->getGPRCalleeSavedArea1Offset();
844 else if (AFI->isGPRCalleeSavedArea2Frame(FI))
845 Offset -= AFI->getGPRCalleeSavedArea2Offset();
846 else if (AFI->isDPRCalleeSavedAreaFrame(FI))
847 Offset -= AFI->getDPRCalleeSavedAreaOffset();
848 else if (needsStackRealignment(MF)) {
849 // When dynamically realigning the stack, use the frame pointer for
850 // parameters, and the stack pointer for locals.
851 assert (hasFP(MF) && "dynamic stack realignment without a FP!");
853 FrameReg = getFrameRegister(MF);
854 Offset -= AFI->getFramePtrSpillOffset();
856 } else if (hasFP(MF) && AFI->hasStackFrame()) {
857 if (isFixed || MFI->hasVarSizedObjects()) {
858 // Use frame pointer to reference fixed objects unless this is a
859 // frameless function.
860 FrameReg = getFrameRegister(MF);
861 Offset -= AFI->getFramePtrSpillOffset();
862 } else if (AFI->isThumb2Function()) {
863 // In Thumb2 mode, the negative offset is very limited.
864 int FPOffset = Offset - AFI->getFramePtrSpillOffset();
865 if (FPOffset >= -255 && FPOffset < 0) {
866 FrameReg = getFrameRegister(MF);
876 ARMBaseRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
879 return getFrameIndexReference(MF, FI, FrameReg);
882 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
883 llvm_unreachable("What is the exception register");
887 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
888 llvm_unreachable("What is the exception handler register");
892 int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
893 return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
896 unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
897 const MachineFunction &MF) const {
900 // Return 0 if either register of the pair is a special register.
909 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6;
911 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
913 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
985 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
986 const MachineFunction &MF) const {
989 // Return 0 if either register of the pair is a special register.
998 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7;
1000 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
1002 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
1074 /// emitLoadConstPool - Emits a load from constpool to materialize the
1075 /// specified immediate.
1076 void ARMBaseRegisterInfo::
1077 emitLoadConstPool(MachineBasicBlock &MBB,
1078 MachineBasicBlock::iterator &MBBI,
1080 unsigned DestReg, unsigned SubIdx, int Val,
1081 ARMCC::CondCodes Pred,
1082 unsigned PredReg) const {
1083 MachineFunction &MF = *MBB.getParent();
1084 MachineConstantPool *ConstantPool = MF.getConstantPool();
1086 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
1087 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
1089 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
1090 .addReg(DestReg, getDefRegState(true), SubIdx)
1091 .addConstantPoolIndex(Idx)
1092 .addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
1095 bool ARMBaseRegisterInfo::
1096 requiresRegisterScavenging(const MachineFunction &MF) const {
1100 bool ARMBaseRegisterInfo::
1101 requiresFrameIndexScavenging(const MachineFunction &MF) const {
1105 // hasReservedCallFrame - Under normal circumstances, when a frame pointer is
1106 // not required, we reserve argument space for call sites in the function
1107 // immediately on entry to the current function. This eliminates the need for
1108 // add/sub sp brackets around call sites. Returns true if the call frame is
1109 // included as part of the stack frame.
1110 bool ARMBaseRegisterInfo::
1111 hasReservedCallFrame(MachineFunction &MF) const {
1112 const MachineFrameInfo *FFI = MF.getFrameInfo();
1113 unsigned CFSize = FFI->getMaxCallFrameSize();
1114 // It's not always a good idea to include the call frame as part of the
1115 // stack frame. ARM (especially Thumb) has small immediate offset to
1116 // address the stack frame. So a large call frame can cause poor codegen
1117 // and may even makes it impossible to scavenge a register.
1118 if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12
1121 return !MF.getFrameInfo()->hasVarSizedObjects();
1124 // canSimplifyCallFramePseudos - If there is a reserved call frame, the
1125 // call frame pseudos can be simplified. Unlike most targets, having a FP
1126 // is not sufficient here since we still may reference some objects via SP
1127 // even when FP is available in Thumb2 mode.
1128 bool ARMBaseRegisterInfo::
1129 canSimplifyCallFramePseudos(MachineFunction &MF) const {
1130 return hasReservedCallFrame(MF) || MF.getFrameInfo()->hasVarSizedObjects();
1134 emitSPUpdate(bool isARM,
1135 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
1136 DebugLoc dl, const ARMBaseInstrInfo &TII,
1138 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
1140 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1141 Pred, PredReg, TII);
1143 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1144 Pred, PredReg, TII);
1148 void ARMBaseRegisterInfo::
1149 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
1150 MachineBasicBlock::iterator I) const {
1151 if (!hasReservedCallFrame(MF)) {
1152 // If we have alloca, convert as follows:
1153 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
1154 // ADJCALLSTACKUP -> add, sp, sp, amount
1155 MachineInstr *Old = I;
1156 DebugLoc dl = Old->getDebugLoc();
1157 unsigned Amount = Old->getOperand(0).getImm();
1159 // We need to keep the stack aligned properly. To do this, we round the
1160 // amount of space needed for the outgoing arguments up to the next
1161 // alignment boundary.
1162 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
1163 Amount = (Amount+Align-1)/Align*Align;
1165 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1166 assert(!AFI->isThumb1OnlyFunction() &&
1167 "This eliminateCallFramePseudoInstr does not support Thumb1!");
1168 bool isARM = !AFI->isThumbFunction();
1170 // Replace the pseudo instruction with a new instruction...
1171 unsigned Opc = Old->getOpcode();
1172 int PIdx = Old->findFirstPredOperandIdx();
1173 ARMCC::CondCodes Pred = (PIdx == -1)
1174 ? ARMCC::AL : (ARMCC::CondCodes)Old->getOperand(PIdx).getImm();
1175 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
1176 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
1177 unsigned PredReg = Old->getOperand(2).getReg();
1178 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
1180 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
1181 unsigned PredReg = Old->getOperand(3).getReg();
1182 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
1183 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
1191 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1192 int SPAdj, FrameIndexValue *Value,
1193 RegScavenger *RS) const {
1195 MachineInstr &MI = *II;
1196 MachineBasicBlock &MBB = *MI.getParent();
1197 MachineFunction &MF = *MBB.getParent();
1198 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1199 assert(!AFI->isThumb1OnlyFunction() &&
1200 "This eliminateFrameIndex does not support Thumb1!");
1202 while (!MI.getOperand(i).isFI()) {
1204 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1207 int FrameIndex = MI.getOperand(i).getIndex();
1210 int Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
1211 if (FrameReg != ARM::SP)
1215 // Special handling of dbg_value instructions.
1216 if (MI.isDebugValue()) {
1217 MI.getOperand(i). ChangeToRegister(FrameReg, false /*isDef*/);
1218 MI.getOperand(i+1).ChangeToImmediate(Offset);
1222 // Modify MI as necessary to handle as much of 'Offset' as possible
1224 if (!AFI->isThumbFunction())
1225 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1227 assert(AFI->isThumb2Function());
1228 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1233 // If we get here, the immediate doesn't fit into the instruction. We folded
1234 // as much as possible above, handle the rest, providing a register that is
1237 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1238 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1239 "This code isn't needed if offset already handled!");
1241 unsigned ScratchReg = 0;
1242 int PIdx = MI.findFirstPredOperandIdx();
1243 ARMCC::CondCodes Pred = (PIdx == -1)
1244 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1245 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1247 // Must be addrmode4/6.
1248 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1250 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1252 Value->first = FrameReg; // use the frame register as a kind indicator
1253 Value->second = Offset;
1255 if (!AFI->isThumbFunction())
1256 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1257 Offset, Pred, PredReg, TII);
1259 assert(AFI->isThumb2Function());
1260 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1261 Offset, Pred, PredReg, TII);
1263 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
1264 if (!ReuseFrameIndexVals)
1270 /// Move iterator past the next bunch of callee save load / store ops for
1271 /// the particular spill area (1: integer area 1, 2: integer area 2,
1272 /// 3: fp area, 0: don't care).
1273 static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
1274 MachineBasicBlock::iterator &MBBI,
1275 int Opc1, int Opc2, unsigned Area,
1276 const ARMSubtarget &STI) {
1277 while (MBBI != MBB.end() &&
1278 ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
1279 MBBI->getOperand(1).isFI()) {
1282 unsigned Category = 0;
1283 switch (MBBI->getOperand(0).getReg()) {
1284 case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7:
1288 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
1289 Category = STI.isTargetDarwin() ? 2 : 1;
1291 case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11:
1292 case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
1299 if (Done || Category != Area)
1307 void ARMBaseRegisterInfo::
1308 emitPrologue(MachineFunction &MF) const {
1309 MachineBasicBlock &MBB = MF.front();
1310 MachineBasicBlock::iterator MBBI = MBB.begin();
1311 MachineFrameInfo *MFI = MF.getFrameInfo();
1312 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1313 assert(!AFI->isThumb1OnlyFunction() &&
1314 "This emitPrologue does not support Thumb1!");
1315 bool isARM = !AFI->isThumbFunction();
1316 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1317 unsigned NumBytes = MFI->getStackSize();
1318 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
1319 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
1321 // Determine the sizes of each callee-save spill areas and record which frame
1322 // belongs to which callee-save spill areas.
1323 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
1324 int FramePtrSpillFI = 0;
1326 // Allocate the vararg register save area. This is not counted in NumBytes.
1328 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
1330 if (!AFI->hasStackFrame()) {
1332 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1336 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
1337 unsigned Reg = CSI[i].getReg();
1338 int FI = CSI[i].getFrameIdx();
1345 if (Reg == FramePtr)
1346 FramePtrSpillFI = FI;
1347 AFI->addGPRCalleeSavedArea1Frame(FI);
1354 if (Reg == FramePtr)
1355 FramePtrSpillFI = FI;
1356 if (STI.isTargetDarwin()) {
1357 AFI->addGPRCalleeSavedArea2Frame(FI);
1360 AFI->addGPRCalleeSavedArea1Frame(FI);
1365 AFI->addDPRCalleeSavedAreaFrame(FI);
1370 // Build the new SUBri to adjust SP for integer callee-save spill area 1.
1371 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
1372 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
1374 // Set FP to point to the stack slot that contains the previous FP.
1375 // For Darwin, FP is R7, which has now been stored in spill area 1.
1376 // Otherwise, if this is not Darwin, all the callee-saved registers go
1377 // into spill area 1, including the FP in R11. In either case, it is
1378 // now safe to emit this assignment.
1379 if (STI.isTargetDarwin() || hasFP(MF)) {
1380 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
1381 MachineInstrBuilder MIB =
1382 BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
1383 .addFrameIndex(FramePtrSpillFI).addImm(0);
1384 AddDefaultCC(AddDefaultPred(MIB));
1387 // Build the new SUBri to adjust SP for integer callee-save spill area 2.
1388 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
1390 // Build the new SUBri to adjust SP for FP callee-save spill area.
1391 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
1392 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
1394 // Determine starting offsets of spill areas.
1395 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
1396 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
1397 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
1398 if (STI.isTargetDarwin() || hasFP(MF))
1399 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) +
1401 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
1402 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
1403 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
1405 movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
1406 NumBytes = DPRCSOffset;
1408 // Adjust SP after all the callee-save spills.
1409 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1412 if (STI.isTargetELF() && hasFP(MF)) {
1413 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
1414 AFI->getFramePtrSpillOffset());
1417 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
1418 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
1419 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
1421 // If we need dynamic stack realignment, do it here.
1422 if (needsStackRealignment(MF)) {
1423 unsigned MaxAlign = MFI->getMaxAlignment();
1424 assert (!AFI->isThumb1OnlyFunction());
1425 if (!AFI->isThumbFunction()) {
1426 // Emit bic sp, sp, MaxAlign
1427 AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
1428 TII.get(ARM::BICri), ARM::SP)
1429 .addReg(ARM::SP, RegState::Kill)
1430 .addImm(MaxAlign-1)));
1432 // We cannot use sp as source/dest register here, thus we're emitting the
1433 // following sequence:
1435 // bic r4, r4, MaxAlign
1437 // FIXME: It will be better just to find spare register here.
1438 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2tgpr), ARM::R4)
1439 .addReg(ARM::SP, RegState::Kill);
1440 AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
1441 TII.get(ARM::t2BICri), ARM::R4)
1442 .addReg(ARM::R4, RegState::Kill)
1443 .addImm(MaxAlign-1)));
1444 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
1445 .addReg(ARM::R4, RegState::Kill);
1450 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
1451 for (unsigned i = 0; CSRegs[i]; ++i)
1452 if (Reg == CSRegs[i])
1457 static bool isCSRestore(MachineInstr *MI,
1458 const ARMBaseInstrInfo &TII,
1459 const unsigned *CSRegs) {
1460 return ((MI->getOpcode() == (int)ARM::VLDRD ||
1461 MI->getOpcode() == (int)ARM::LDR ||
1462 MI->getOpcode() == (int)ARM::t2LDRi12) &&
1463 MI->getOperand(1).isFI() &&
1464 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
1467 void ARMBaseRegisterInfo::
1468 emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
1469 MachineBasicBlock::iterator MBBI = prior(MBB.end());
1470 assert(MBBI->getDesc().isReturn() &&
1471 "Can only insert epilog into returning blocks");
1472 DebugLoc dl = MBBI->getDebugLoc();
1473 MachineFrameInfo *MFI = MF.getFrameInfo();
1474 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1475 assert(!AFI->isThumb1OnlyFunction() &&
1476 "This emitEpilogue does not support Thumb1!");
1477 bool isARM = !AFI->isThumbFunction();
1479 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1480 int NumBytes = (int)MFI->getStackSize();
1482 if (!AFI->hasStackFrame()) {
1484 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1486 // Unwind MBBI to point to first LDR / VLDRD.
1487 const unsigned *CSRegs = getCalleeSavedRegs();
1488 if (MBBI != MBB.begin()) {
1491 while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
1492 if (!isCSRestore(MBBI, TII, CSRegs))
1496 // Move SP to start of FP callee save spill area.
1497 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
1498 AFI->getGPRCalleeSavedArea2Size() +
1499 AFI->getDPRCalleeSavedAreaSize());
1501 // Darwin ABI requires FP to point to the stack slot that contains the
1503 bool HasFP = hasFP(MF);
1504 if ((STI.isTargetDarwin() && NumBytes) || HasFP) {
1505 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
1506 // Reset SP based on frame pointer only if the stack frame extends beyond
1507 // frame pointer stack slot or target is ELF and the function has FP.
1509 AFI->getGPRCalleeSavedArea2Size() ||
1510 AFI->getDPRCalleeSavedAreaSize() ||
1511 AFI->getDPRCalleeSavedAreaOffset()) {
1514 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1517 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1522 BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
1524 .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
1526 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
1530 } else if (NumBytes)
1531 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1533 // Move SP to start of integer callee save spill area 2.
1534 movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
1535 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
1537 // Move SP to start of integer callee save spill area 1.
1538 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
1539 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
1541 // Move SP to SP upon entry to the function.
1542 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
1543 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
1547 emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
1550 #include "ARMGenRegisterInfo.inc"