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"));
47 unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
55 llvm_unreachable("Unknown ARM register!");
56 case R0: case D0: case Q0: return 0;
57 case R1: case D1: case Q1: return 1;
58 case R2: case D2: case Q2: return 2;
59 case R3: case D3: case Q3: return 3;
60 case R4: case D4: case Q4: return 4;
61 case R5: case D5: case Q5: return 5;
62 case R6: case D6: case Q6: return 6;
63 case R7: case D7: case Q7: return 7;
64 case R8: case D8: case Q8: return 8;
65 case R9: case D9: case Q9: return 9;
66 case R10: case D10: case Q10: return 10;
67 case R11: case D11: case Q11: return 11;
68 case R12: case D12: case Q12: return 12;
69 case SP: case D13: case Q13: return 13;
70 case LR: case D14: case Q14: return 14;
71 case PC: case D15: case Q15: return 15;
90 case S0: case S1: case S2: case S3:
91 case S4: case S5: case S6: case S7:
92 case S8: case S9: case S10: case S11:
93 case S12: case S13: case S14: case S15:
94 case S16: case S17: case S18: case S19:
95 case S20: case S21: case S22: case S23:
96 case S24: case S25: case S26: case S27:
97 case S28: case S29: case S30: case S31: {
101 default: return 0; // Avoid compile time warning.
139 ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
140 const ARMSubtarget &sti)
141 : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
143 FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
147 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
148 static const unsigned CalleeSavedRegs[] = {
149 ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
150 ARM::R7, ARM::R6, ARM::R5, ARM::R4,
152 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
153 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
157 static const unsigned DarwinCalleeSavedRegs[] = {
158 // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
160 ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
161 ARM::R11, ARM::R10, ARM::R8,
163 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
164 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
167 return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
170 const TargetRegisterClass* const *
171 ARMBaseRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
172 static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
173 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
174 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
175 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
177 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
178 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
182 static const TargetRegisterClass * const ThumbCalleeSavedRegClasses[] = {
183 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
184 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::tGPRRegClass,
185 &ARM::tGPRRegClass,&ARM::tGPRRegClass,&ARM::tGPRRegClass,
187 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
188 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
192 static const TargetRegisterClass * const DarwinCalleeSavedRegClasses[] = {
193 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
194 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
195 &ARM::GPRRegClass, &ARM::GPRRegClass,
197 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
198 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
202 static const TargetRegisterClass * const DarwinThumbCalleeSavedRegClasses[] ={
203 &ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass,
204 &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::GPRRegClass,
205 &ARM::GPRRegClass, &ARM::GPRRegClass,
207 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
208 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
212 if (STI.isThumb1Only()) {
213 return STI.isTargetDarwin()
214 ? DarwinThumbCalleeSavedRegClasses : ThumbCalleeSavedRegClasses;
216 return STI.isTargetDarwin()
217 ? DarwinCalleeSavedRegClasses : CalleeSavedRegClasses;
220 BitVector ARMBaseRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
221 // FIXME: avoid re-calculating this everytime.
222 BitVector Reserved(getNumRegs());
223 Reserved.set(ARM::SP);
224 Reserved.set(ARM::PC);
225 if (STI.isTargetDarwin() || hasFP(MF))
226 Reserved.set(FramePtr);
227 // Some targets reserve R9.
228 if (STI.isR9Reserved())
229 Reserved.set(ARM::R9);
233 bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
234 unsigned Reg) const {
242 if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
246 return STI.isR9Reserved();
252 const TargetRegisterClass *
253 ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
254 const TargetRegisterClass *B,
255 unsigned SubIdx) const {
263 if (A->getSize() == 8) {
264 if (B == &ARM::SPR_8RegClass)
265 return &ARM::DPR_8RegClass;
266 assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
267 if (A == &ARM::DPR_8RegClass)
269 return &ARM::DPR_VFP2RegClass;
272 assert(A->getSize() == 16 && "Expecting a Q register class!");
273 if (B == &ARM::SPR_8RegClass)
274 return &ARM::QPR_8RegClass;
275 return &ARM::QPR_VFP2RegClass;
279 if (B == &ARM::DPR_VFP2RegClass)
280 return &ARM::QPR_VFP2RegClass;
281 if (B == &ARM::DPR_8RegClass)
282 return &ARM::QPR_8RegClass;
288 const TargetRegisterClass *
289 ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
290 return ARM::GPRRegisterClass;
293 /// getAllocationOrder - Returns the register allocation order for a specified
294 /// register class in the form of a pair of TargetRegisterClass iterators.
295 std::pair<TargetRegisterClass::iterator,TargetRegisterClass::iterator>
296 ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
297 unsigned HintType, unsigned HintReg,
298 const MachineFunction &MF) const {
299 // Alternative register allocation orders when favoring even / odd registers
300 // of register pairs.
302 // No FP, R9 is available.
303 static const unsigned GPREven1[] = {
304 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
305 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
308 static const unsigned GPROdd1[] = {
309 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
310 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
314 // FP is R7, R9 is available.
315 static const unsigned GPREven2[] = {
316 ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
317 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
320 static const unsigned GPROdd2[] = {
321 ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
322 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
326 // FP is R11, R9 is available.
327 static const unsigned GPREven3[] = {
328 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
329 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
332 static const unsigned GPROdd3[] = {
333 ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
334 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
338 // No FP, R9 is not available.
339 static const unsigned GPREven4[] = {
340 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
341 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
344 static const unsigned GPROdd4[] = {
345 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
346 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
350 // FP is R7, R9 is not available.
351 static const unsigned GPREven5[] = {
352 ARM::R0, ARM::R2, ARM::R4, ARM::R10,
353 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
356 static const unsigned GPROdd5[] = {
357 ARM::R1, ARM::R3, ARM::R5, ARM::R11,
358 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
362 // FP is R11, R9 is not available.
363 static const unsigned GPREven6[] = {
364 ARM::R0, ARM::R2, ARM::R4, ARM::R6,
365 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
367 static const unsigned GPROdd6[] = {
368 ARM::R1, ARM::R3, ARM::R5, ARM::R7,
369 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
373 if (HintType == ARMRI::RegPairEven) {
374 if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
375 // It's no longer possible to fulfill this hint. Return the default
377 return std::make_pair(RC->allocation_order_begin(MF),
378 RC->allocation_order_end(MF));
380 if (!STI.isTargetDarwin() && !hasFP(MF)) {
381 if (!STI.isR9Reserved())
382 return std::make_pair(GPREven1,
383 GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
385 return std::make_pair(GPREven4,
386 GPREven4 + (sizeof(GPREven4)/sizeof(unsigned)));
387 } else if (FramePtr == ARM::R7) {
388 if (!STI.isR9Reserved())
389 return std::make_pair(GPREven2,
390 GPREven2 + (sizeof(GPREven2)/sizeof(unsigned)));
392 return std::make_pair(GPREven5,
393 GPREven5 + (sizeof(GPREven5)/sizeof(unsigned)));
394 } else { // FramePtr == ARM::R11
395 if (!STI.isR9Reserved())
396 return std::make_pair(GPREven3,
397 GPREven3 + (sizeof(GPREven3)/sizeof(unsigned)));
399 return std::make_pair(GPREven6,
400 GPREven6 + (sizeof(GPREven6)/sizeof(unsigned)));
402 } else if (HintType == ARMRI::RegPairOdd) {
403 if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
404 // It's no longer possible to fulfill this hint. Return the default
406 return std::make_pair(RC->allocation_order_begin(MF),
407 RC->allocation_order_end(MF));
409 if (!STI.isTargetDarwin() && !hasFP(MF)) {
410 if (!STI.isR9Reserved())
411 return std::make_pair(GPROdd1,
412 GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
414 return std::make_pair(GPROdd4,
415 GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned)));
416 } else if (FramePtr == ARM::R7) {
417 if (!STI.isR9Reserved())
418 return std::make_pair(GPROdd2,
419 GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned)));
421 return std::make_pair(GPROdd5,
422 GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned)));
423 } else { // FramePtr == ARM::R11
424 if (!STI.isR9Reserved())
425 return std::make_pair(GPROdd3,
426 GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned)));
428 return std::make_pair(GPROdd6,
429 GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned)));
432 return std::make_pair(RC->allocation_order_begin(MF),
433 RC->allocation_order_end(MF));
436 /// ResolveRegAllocHint - Resolves the specified register allocation hint
437 /// to a physical register. Returns the physical register if it is successful.
439 ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
440 const MachineFunction &MF) const {
441 if (Reg == 0 || !isPhysicalRegister(Reg))
445 else if (Type == (unsigned)ARMRI::RegPairOdd)
447 return getRegisterPairOdd(Reg, MF);
448 else if (Type == (unsigned)ARMRI::RegPairEven)
450 return getRegisterPairEven(Reg, MF);
455 ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
456 MachineFunction &MF) const {
457 MachineRegisterInfo *MRI = &MF.getRegInfo();
458 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
459 if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
460 Hint.first == (unsigned)ARMRI::RegPairEven) &&
461 Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) {
462 // If 'Reg' is one of the even / odd register pair and it's now changed
463 // (e.g. coalesced) into a different register. The other register of the
464 // pair allocation hint must be updated to reflect the relationship
466 unsigned OtherReg = Hint.second;
467 Hint = MRI->getRegAllocationHint(OtherReg);
468 if (Hint.second == Reg)
469 // Make sure the pair has not already divorced.
470 MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
474 static unsigned calculateMaxStackAlignment(const MachineFrameInfo *FFI) {
475 unsigned MaxAlign = 0;
477 for (int i = FFI->getObjectIndexBegin(),
478 e = FFI->getObjectIndexEnd(); i != e; ++i) {
479 if (FFI->isDeadObjectIndex(i))
482 unsigned Align = FFI->getObjectAlignment(i);
483 MaxAlign = std::max(MaxAlign, Align);
489 /// hasFP - Return true if the specified function should have a dedicated frame
490 /// pointer register. This is true if the function has variable sized allocas
491 /// or if frame pointer elimination is disabled.
493 bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
494 const MachineFrameInfo *MFI = MF.getFrameInfo();
495 return (NoFramePointerElim ||
496 needsStackRealignment(MF) ||
497 MFI->hasVarSizedObjects() ||
498 MFI->isFrameAddressTaken());
501 bool ARMBaseRegisterInfo::
502 needsStackRealignment(const MachineFunction &MF) const {
503 const MachineFrameInfo *MFI = MF.getFrameInfo();
504 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
505 unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
506 return (RealignStack &&
507 !AFI->isThumb1OnlyFunction() &&
508 (MFI->getMaxAlignment() > StackAlign) &&
509 !MFI->hasVarSizedObjects());
512 bool ARMBaseRegisterInfo::cannotEliminateFrame(const MachineFunction &MF) const {
513 const MachineFrameInfo *MFI = MF.getFrameInfo();
514 if (NoFramePointerElim && MFI->hasCalls())
516 return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
517 || needsStackRealignment(MF);
520 /// estimateStackSize - Estimate and return the size of the frame.
521 static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) {
522 const MachineFrameInfo *FFI = MF.getFrameInfo();
524 for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
525 int FixedOff = -FFI->getObjectOffset(i);
526 if (FixedOff > Offset) Offset = FixedOff;
528 for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
529 if (FFI->isDeadObjectIndex(i))
531 Offset += FFI->getObjectSize(i);
532 unsigned Align = FFI->getObjectAlignment(i);
533 // Adjust to alignment boundary
534 Offset = (Offset+Align-1)/Align*Align;
536 return (unsigned)Offset;
539 /// estimateRSStackSizeLimit - Look at each instruction that references stack
540 /// frames and return the stack size limit beyond which some of these
541 /// instructions will require scratch register during their expansion later.
543 ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
544 unsigned Limit = (1 << 12) - 1;
545 for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
546 for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
548 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
549 if (!I->getOperand(i).isFI()) continue;
551 const TargetInstrDesc &Desc = TII.get(I->getOpcode());
552 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
553 if (AddrMode == ARMII::AddrMode3 ||
554 AddrMode == ARMII::AddrModeT2_i8)
557 if (AddrMode == ARMII::AddrMode5 ||
558 AddrMode == ARMII::AddrModeT2_i8s4)
559 Limit = std::min(Limit, ((1U << 8) - 1) * 4);
561 if (AddrMode == ARMII::AddrModeT2_i12 && hasFP(MF))
562 // When the stack offset is negative, we will end up using
563 // the i8 instructions instead.
565 break; // At most one FI per instruction
574 ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
575 RegScavenger *RS) const {
576 // This tells PEI to spill the FP as if it is any other callee-save register
577 // to take advantage the eliminateFrameIndex machinery. This also ensures it
578 // is spilled in the order specified by getCalleeSavedRegs() to make it easier
579 // to combine multiple loads / stores.
580 bool CanEliminateFrame = true;
581 bool CS1Spilled = false;
582 bool LRSpilled = false;
583 unsigned NumGPRSpills = 0;
584 SmallVector<unsigned, 4> UnspilledCS1GPRs;
585 SmallVector<unsigned, 4> UnspilledCS2GPRs;
586 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
588 MachineFrameInfo *MFI = MF.getFrameInfo();
590 // Calculate and set max stack object alignment early, so we can decide
591 // whether we will need stack realignment (and thus FP).
593 unsigned MaxAlign = std::max(MFI->getMaxAlignment(),
594 calculateMaxStackAlignment(MFI));
595 MFI->setMaxAlignment(MaxAlign);
598 // Don't spill FP if the frame can be eliminated. This is determined
599 // by scanning the callee-save registers to see if any is used.
600 const unsigned *CSRegs = getCalleeSavedRegs();
601 const TargetRegisterClass* const *CSRegClasses = getCalleeSavedRegClasses();
602 for (unsigned i = 0; CSRegs[i]; ++i) {
603 unsigned Reg = CSRegs[i];
604 bool Spilled = false;
605 if (MF.getRegInfo().isPhysRegUsed(Reg)) {
606 AFI->setCSRegisterIsSpilled(Reg);
608 CanEliminateFrame = false;
610 // Check alias registers too.
611 for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
612 if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
614 CanEliminateFrame = false;
619 if (CSRegClasses[i] == ARM::GPRRegisterClass ||
620 CSRegClasses[i] == ARM::tGPRRegisterClass) {
624 if (!STI.isTargetDarwin()) {
631 // Keep track if LR and any of R4, R5, R6, and R7 is spilled.
646 if (!STI.isTargetDarwin()) {
647 UnspilledCS1GPRs.push_back(Reg);
657 UnspilledCS1GPRs.push_back(Reg);
660 UnspilledCS2GPRs.push_back(Reg);
667 bool ForceLRSpill = false;
668 if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
669 unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
670 // Force LR to be spilled if the Thumb function size is > 2048. This enables
671 // use of BL to implement far jump. If it turns out that it's not needed
672 // then the branch fix up path will undo it.
673 if (FnSize >= (1 << 11)) {
674 CanEliminateFrame = false;
679 bool ExtraCSSpill = false;
680 if (!CanEliminateFrame || cannotEliminateFrame(MF)) {
681 AFI->setHasStackFrame(true);
683 // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
684 // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
685 if (!LRSpilled && CS1Spilled) {
686 MF.getRegInfo().setPhysRegUsed(ARM::LR);
687 AFI->setCSRegisterIsSpilled(ARM::LR);
689 UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
690 UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
691 ForceLRSpill = false;
695 // Darwin ABI requires FP to point to the stack slot that contains the
697 if (STI.isTargetDarwin() || hasFP(MF)) {
698 MF.getRegInfo().setPhysRegUsed(FramePtr);
702 // If stack and double are 8-byte aligned and we are spilling an odd number
703 // of GPRs. Spill one extra callee save GPR so we won't have to pad between
704 // the integer and double callee save areas.
705 unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
706 if (TargetAlign == 8 && (NumGPRSpills & 1)) {
707 if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
708 for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
709 unsigned Reg = UnspilledCS1GPRs[i];
710 // Don't spill high register if the function is thumb1
711 if (!AFI->isThumb1OnlyFunction() ||
712 isARMLowRegister(Reg) || Reg == ARM::LR) {
713 MF.getRegInfo().setPhysRegUsed(Reg);
714 AFI->setCSRegisterIsSpilled(Reg);
715 if (!isReservedReg(MF, Reg))
720 } else if (!UnspilledCS2GPRs.empty() &&
721 !AFI->isThumb1OnlyFunction()) {
722 unsigned Reg = UnspilledCS2GPRs.front();
723 MF.getRegInfo().setPhysRegUsed(Reg);
724 AFI->setCSRegisterIsSpilled(Reg);
725 if (!isReservedReg(MF, Reg))
730 // Estimate if we might need to scavenge a register at some point in order
731 // to materialize a stack offset. If so, either spill one additional
732 // callee-saved register or reserve a special spill slot to facilitate
733 // register scavenging. Thumb1 needs a spill slot for stack pointer
734 // adjustments also, even when the frame itself is small.
735 if (RS && !ExtraCSSpill) {
736 MachineFrameInfo *MFI = MF.getFrameInfo();
737 // If any of the stack slot references may be out of range of an
738 // immediate offset, make sure a register (or a spill slot) is
739 // available for the register scavenger. Note that if we're indexing
740 // off the frame pointer, the effective stack size is 4 bytes larger
741 // since the FP points to the stack slot of the previous FP.
742 if (estimateStackSize(MF, MFI) + (hasFP(MF) ? 4 : 0)
743 >= estimateRSStackSizeLimit(MF)) {
744 // If any non-reserved CS register isn't spilled, just spill one or two
745 // extra. That should take care of it!
746 unsigned NumExtras = TargetAlign / 4;
747 SmallVector<unsigned, 2> Extras;
748 while (NumExtras && !UnspilledCS1GPRs.empty()) {
749 unsigned Reg = UnspilledCS1GPRs.back();
750 UnspilledCS1GPRs.pop_back();
751 if (!isReservedReg(MF, Reg)) {
752 Extras.push_back(Reg);
756 // For non-Thumb1 functions, also check for hi-reg CS registers
757 if (!AFI->isThumb1OnlyFunction()) {
758 while (NumExtras && !UnspilledCS2GPRs.empty()) {
759 unsigned Reg = UnspilledCS2GPRs.back();
760 UnspilledCS2GPRs.pop_back();
761 if (!isReservedReg(MF, Reg)) {
762 Extras.push_back(Reg);
767 if (Extras.size() && NumExtras == 0) {
768 for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
769 MF.getRegInfo().setPhysRegUsed(Extras[i]);
770 AFI->setCSRegisterIsSpilled(Extras[i]);
772 } else if (!AFI->isThumb1OnlyFunction()) {
773 // note: Thumb1 functions spill to R12, not the stack.
774 // Reserve a slot closest to SP or frame pointer.
775 const TargetRegisterClass *RC = ARM::GPRRegisterClass;
776 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
785 MF.getRegInfo().setPhysRegUsed(ARM::LR);
786 AFI->setCSRegisterIsSpilled(ARM::LR);
787 AFI->setLRIsSpilledForFarJump(true);
791 unsigned ARMBaseRegisterInfo::getRARegister() const {
796 ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
797 if (STI.isTargetDarwin() || hasFP(MF))
803 ARMBaseRegisterInfo::getFrameIndexReference(MachineFunction &MF, int FI,
804 unsigned &FrameReg) const {
805 const MachineFrameInfo *MFI = MF.getFrameInfo();
806 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
807 int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize();
808 bool isFixed = MFI->isFixedObjectIndex(FI);
811 if (AFI->isGPRCalleeSavedArea1Frame(FI))
812 Offset -= AFI->getGPRCalleeSavedArea1Offset();
813 else if (AFI->isGPRCalleeSavedArea2Frame(FI))
814 Offset -= AFI->getGPRCalleeSavedArea2Offset();
815 else if (AFI->isDPRCalleeSavedAreaFrame(FI))
816 Offset -= AFI->getDPRCalleeSavedAreaOffset();
817 else if (needsStackRealignment(MF)) {
818 // When dynamically realigning the stack, use the frame pointer for
819 // parameters, and the stack pointer for locals.
820 assert (hasFP(MF) && "dynamic stack realignment without a FP!");
822 FrameReg = getFrameRegister(MF);
823 Offset -= AFI->getFramePtrSpillOffset();
825 } else if (hasFP(MF) && AFI->hasStackFrame()) {
826 if (isFixed || MFI->hasVarSizedObjects()) {
827 // Use frame pointer to reference fixed objects unless this is a
828 // frameless function.
829 FrameReg = getFrameRegister(MF);
830 Offset -= AFI->getFramePtrSpillOffset();
831 } else if (AFI->isThumb2Function()) {
832 // In Thumb2 mode, the negative offset is very limited.
833 int FPOffset = Offset - AFI->getFramePtrSpillOffset();
834 if (FPOffset >= -255 && FPOffset < 0) {
835 FrameReg = getFrameRegister(MF);
845 ARMBaseRegisterInfo::getFrameIndexOffset(MachineFunction &MF, int FI) const {
847 return getFrameIndexReference(MF, FI, FrameReg);
850 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
851 llvm_unreachable("What is the exception register");
855 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
856 llvm_unreachable("What is the exception handler register");
860 int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
861 return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
864 unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
865 const MachineFunction &MF) const {
868 // Return 0 if either register of the pair is a special register.
877 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6;
879 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
881 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
953 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
954 const MachineFunction &MF) const {
957 // Return 0 if either register of the pair is a special register.
966 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7;
968 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
970 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
1042 /// emitLoadConstPool - Emits a load from constpool to materialize the
1043 /// specified immediate.
1044 void ARMBaseRegisterInfo::
1045 emitLoadConstPool(MachineBasicBlock &MBB,
1046 MachineBasicBlock::iterator &MBBI,
1048 unsigned DestReg, unsigned SubIdx, int Val,
1049 ARMCC::CondCodes Pred,
1050 unsigned PredReg) const {
1051 MachineFunction &MF = *MBB.getParent();
1052 MachineConstantPool *ConstantPool = MF.getConstantPool();
1054 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
1055 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
1057 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
1058 .addReg(DestReg, getDefRegState(true), SubIdx)
1059 .addConstantPoolIndex(Idx)
1060 .addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
1063 bool ARMBaseRegisterInfo::
1064 requiresRegisterScavenging(const MachineFunction &MF) const {
1068 bool ARMBaseRegisterInfo::
1069 requiresFrameIndexScavenging(const MachineFunction &MF) const {
1073 // hasReservedCallFrame - Under normal circumstances, when a frame pointer is
1074 // not required, we reserve argument space for call sites in the function
1075 // immediately on entry to the current function. This eliminates the need for
1076 // add/sub sp brackets around call sites. Returns true if the call frame is
1077 // included as part of the stack frame.
1078 bool ARMBaseRegisterInfo::
1079 hasReservedCallFrame(MachineFunction &MF) const {
1080 const MachineFrameInfo *FFI = MF.getFrameInfo();
1081 unsigned CFSize = FFI->getMaxCallFrameSize();
1082 // It's not always a good idea to include the call frame as part of the
1083 // stack frame. ARM (especially Thumb) has small immediate offset to
1084 // address the stack frame. So a large call frame can cause poor codegen
1085 // and may even makes it impossible to scavenge a register.
1086 if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12
1089 return !MF.getFrameInfo()->hasVarSizedObjects();
1093 emitSPUpdate(bool isARM,
1094 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
1095 DebugLoc dl, const ARMBaseInstrInfo &TII,
1097 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
1099 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1100 Pred, PredReg, TII);
1102 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1103 Pred, PredReg, TII);
1107 void ARMBaseRegisterInfo::
1108 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
1109 MachineBasicBlock::iterator I) const {
1110 if (!hasReservedCallFrame(MF)) {
1111 // If we have alloca, convert as follows:
1112 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
1113 // ADJCALLSTACKUP -> add, sp, sp, amount
1114 MachineInstr *Old = I;
1115 DebugLoc dl = Old->getDebugLoc();
1116 unsigned Amount = Old->getOperand(0).getImm();
1118 // We need to keep the stack aligned properly. To do this, we round the
1119 // amount of space needed for the outgoing arguments up to the next
1120 // alignment boundary.
1121 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
1122 Amount = (Amount+Align-1)/Align*Align;
1124 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1125 assert(!AFI->isThumb1OnlyFunction() &&
1126 "This eliminateCallFramePseudoInstr does not suppor Thumb1!");
1127 bool isARM = !AFI->isThumbFunction();
1129 // Replace the pseudo instruction with a new instruction...
1130 unsigned Opc = Old->getOpcode();
1131 ARMCC::CondCodes Pred = (ARMCC::CondCodes)Old->getOperand(1).getImm();
1132 // FIXME: Thumb2 version of ADJCALLSTACKUP and ADJCALLSTACKDOWN?
1133 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
1134 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
1135 unsigned PredReg = Old->getOperand(2).getReg();
1136 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
1138 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
1139 unsigned PredReg = Old->getOperand(3).getReg();
1140 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
1141 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
1149 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1150 int SPAdj, int *Value,
1151 RegScavenger *RS) const {
1153 MachineInstr &MI = *II;
1154 MachineBasicBlock &MBB = *MI.getParent();
1155 MachineFunction &MF = *MBB.getParent();
1156 const MachineFrameInfo *MFI = MF.getFrameInfo();
1157 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1158 assert(!AFI->isThumb1OnlyFunction() &&
1159 "This eliminateFrameIndex does not support Thumb1!");
1161 while (!MI.getOperand(i).isFI()) {
1163 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1166 int FrameIndex = MI.getOperand(i).getIndex();
1167 int Offset = MFI->getObjectOffset(FrameIndex) + MFI->getStackSize() + SPAdj;
1170 Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
1171 if (FrameReg != ARM::SP)
1174 // Modify MI as necessary to handle as much of 'Offset' as possible
1176 if (!AFI->isThumbFunction())
1177 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1179 assert(AFI->isThumb2Function());
1180 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1185 // If we get here, the immediate doesn't fit into the instruction. We folded
1186 // as much as possible above, handle the rest, providing a register that is
1189 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1190 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1191 "This code isn't needed if offset already handled!");
1193 unsigned ScratchReg = 0;
1194 int PIdx = MI.findFirstPredOperandIdx();
1195 ARMCC::CondCodes Pred = (PIdx == -1)
1196 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1197 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1199 // Must be addrmode4/6.
1200 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1202 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1203 if (Value) *Value = Offset;
1204 if (!AFI->isThumbFunction())
1205 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1206 Offset, Pred, PredReg, TII);
1208 assert(AFI->isThumb2Function());
1209 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1210 Offset, Pred, PredReg, TII);
1212 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
1213 if (!ReuseFrameIndexVals)
1219 /// Move iterator past the next bunch of callee save load / store ops for
1220 /// the particular spill area (1: integer area 1, 2: integer area 2,
1221 /// 3: fp area, 0: don't care).
1222 static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
1223 MachineBasicBlock::iterator &MBBI,
1224 int Opc1, int Opc2, unsigned Area,
1225 const ARMSubtarget &STI) {
1226 while (MBBI != MBB.end() &&
1227 ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
1228 MBBI->getOperand(1).isFI()) {
1231 unsigned Category = 0;
1232 switch (MBBI->getOperand(0).getReg()) {
1233 case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7:
1237 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
1238 Category = STI.isTargetDarwin() ? 2 : 1;
1240 case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11:
1241 case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
1248 if (Done || Category != Area)
1256 void ARMBaseRegisterInfo::
1257 emitPrologue(MachineFunction &MF) const {
1258 MachineBasicBlock &MBB = MF.front();
1259 MachineBasicBlock::iterator MBBI = MBB.begin();
1260 MachineFrameInfo *MFI = MF.getFrameInfo();
1261 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1262 assert(!AFI->isThumb1OnlyFunction() &&
1263 "This emitPrologue does not suppor Thumb1!");
1264 bool isARM = !AFI->isThumbFunction();
1265 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1266 unsigned NumBytes = MFI->getStackSize();
1267 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
1268 DebugLoc dl = (MBBI != MBB.end() ?
1269 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
1271 // Determine the sizes of each callee-save spill areas and record which frame
1272 // belongs to which callee-save spill areas.
1273 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
1274 int FramePtrSpillFI = 0;
1276 // Allocate the vararg register save area. This is not counted in NumBytes.
1278 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
1280 if (!AFI->hasStackFrame()) {
1282 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1286 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
1287 unsigned Reg = CSI[i].getReg();
1288 int FI = CSI[i].getFrameIdx();
1295 if (Reg == FramePtr)
1296 FramePtrSpillFI = FI;
1297 AFI->addGPRCalleeSavedArea1Frame(FI);
1304 if (Reg == FramePtr)
1305 FramePtrSpillFI = FI;
1306 if (STI.isTargetDarwin()) {
1307 AFI->addGPRCalleeSavedArea2Frame(FI);
1310 AFI->addGPRCalleeSavedArea1Frame(FI);
1315 AFI->addDPRCalleeSavedAreaFrame(FI);
1320 // Build the new SUBri to adjust SP for integer callee-save spill area 1.
1321 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
1322 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
1324 // Set FP to point to the stack slot that contains the previous FP.
1325 // For Darwin, FP is R7, which has now been stored in spill area 1.
1326 // Otherwise, if this is not Darwin, all the callee-saved registers go
1327 // into spill area 1, including the FP in R11. In either case, it is
1328 // now safe to emit this assignment.
1329 if (STI.isTargetDarwin() || hasFP(MF)) {
1330 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
1331 MachineInstrBuilder MIB =
1332 BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
1333 .addFrameIndex(FramePtrSpillFI).addImm(0);
1334 AddDefaultCC(AddDefaultPred(MIB));
1337 // Build the new SUBri to adjust SP for integer callee-save spill area 2.
1338 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
1340 // Build the new SUBri to adjust SP for FP callee-save spill area.
1341 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
1342 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
1344 // Determine starting offsets of spill areas.
1345 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
1346 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
1347 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
1348 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
1349 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
1350 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
1351 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
1353 movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
1354 NumBytes = DPRCSOffset;
1356 // Adjust SP after all the callee-save spills.
1357 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1360 if (STI.isTargetELF() && hasFP(MF)) {
1361 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
1362 AFI->getFramePtrSpillOffset());
1365 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
1366 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
1367 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
1369 // If we need dynamic stack realignment, do it here.
1370 if (needsStackRealignment(MF)) {
1372 unsigned MaxAlign = MFI->getMaxAlignment();
1373 assert (!AFI->isThumb1OnlyFunction());
1374 Opc = AFI->isThumbFunction() ? ARM::t2BICri : ARM::BICri;
1376 AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), ARM::SP)
1377 .addReg(ARM::SP, RegState::Kill)
1378 .addImm(MaxAlign-1)));
1382 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
1383 for (unsigned i = 0; CSRegs[i]; ++i)
1384 if (Reg == CSRegs[i])
1389 static bool isCSRestore(MachineInstr *MI,
1390 const ARMBaseInstrInfo &TII,
1391 const unsigned *CSRegs) {
1392 return ((MI->getOpcode() == (int)ARM::VLDRD ||
1393 MI->getOpcode() == (int)ARM::LDR ||
1394 MI->getOpcode() == (int)ARM::t2LDRi12) &&
1395 MI->getOperand(1).isFI() &&
1396 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
1399 void ARMBaseRegisterInfo::
1400 emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
1401 MachineBasicBlock::iterator MBBI = prior(MBB.end());
1402 assert(MBBI->getDesc().isReturn() &&
1403 "Can only insert epilog into returning blocks");
1404 DebugLoc dl = MBBI->getDebugLoc();
1405 MachineFrameInfo *MFI = MF.getFrameInfo();
1406 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1407 assert(!AFI->isThumb1OnlyFunction() &&
1408 "This emitEpilogue does not suppor Thumb1!");
1409 bool isARM = !AFI->isThumbFunction();
1411 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1412 int NumBytes = (int)MFI->getStackSize();
1414 if (!AFI->hasStackFrame()) {
1416 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1418 // Unwind MBBI to point to first LDR / VLDRD.
1419 const unsigned *CSRegs = getCalleeSavedRegs();
1420 if (MBBI != MBB.begin()) {
1423 while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
1424 if (!isCSRestore(MBBI, TII, CSRegs))
1428 // Move SP to start of FP callee save spill area.
1429 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
1430 AFI->getGPRCalleeSavedArea2Size() +
1431 AFI->getDPRCalleeSavedAreaSize());
1433 // Darwin ABI requires FP to point to the stack slot that contains the
1435 bool HasFP = hasFP(MF);
1436 if ((STI.isTargetDarwin() && NumBytes) || HasFP) {
1437 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
1438 // Reset SP based on frame pointer only if the stack frame extends beyond
1439 // frame pointer stack slot or target is ELF and the function has FP.
1441 AFI->getGPRCalleeSavedArea2Size() ||
1442 AFI->getDPRCalleeSavedAreaSize() ||
1443 AFI->getDPRCalleeSavedAreaOffset()) {
1446 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1449 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1454 BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
1456 .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
1458 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
1462 } else if (NumBytes)
1463 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1465 // Move SP to start of integer callee save spill area 2.
1466 movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
1467 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
1469 // Move SP to start of integer callee save spill area 1.
1470 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
1471 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
1473 // Move SP to SP upon entry to the function.
1474 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
1475 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
1479 emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
1483 struct MaximalStackAlignmentCalculator : public MachineFunctionPass {
1485 MaximalStackAlignmentCalculator() : MachineFunctionPass(&ID) {}
1487 virtual bool runOnMachineFunction(MachineFunction &MF) {
1488 MachineFrameInfo *FFI = MF.getFrameInfo();
1489 MachineRegisterInfo &RI = MF.getRegInfo();
1491 // Calculate max stack alignment of all already allocated stack objects.
1492 unsigned MaxAlign = calculateMaxStackAlignment(FFI);
1494 // Be over-conservative: scan over all vreg defs and find, whether vector
1495 // registers are used. If yes - there is probability, that vector register
1496 // will be spilled and thus stack needs to be aligned properly.
1497 for (unsigned RegNum = TargetRegisterInfo::FirstVirtualRegister;
1498 RegNum < RI.getLastVirtReg(); ++RegNum)
1499 MaxAlign = std::max(MaxAlign, RI.getRegClass(RegNum)->getAlignment());
1501 if (FFI->getMaxAlignment() == MaxAlign)
1504 FFI->setMaxAlignment(MaxAlign);
1508 virtual const char *getPassName() const {
1509 return "ARM Stack Required Alignment Auto-Detector";
1512 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
1513 AU.setPreservesCFG();
1514 MachineFunctionPass::getAnalysisUsage(AU);
1518 char MaximalStackAlignmentCalculator::ID = 0;
1522 llvm::createARMMaxStackAlignmentCalculatorPass() {
1523 return new MaximalStackAlignmentCalculator();
1526 #include "ARMGenRegisterInfo.inc"