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/ErrorHandling.h"
33 #include "llvm/Support/raw_ostream.h"
34 #include "llvm/Target/TargetFrameInfo.h"
35 #include "llvm/Target/TargetMachine.h"
36 #include "llvm/Target/TargetOptions.h"
37 #include "llvm/ADT/BitVector.h"
38 #include "llvm/ADT/SmallVector.h"
39 #include "llvm/Support/CommandLine.h"
43 ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(false),
44 cl::desc("Reuse repeated frame index values"));
46 unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
54 llvm_unreachable("Unknown ARM register!");
55 case R0: case D0: case Q0: return 0;
56 case R1: case D1: case Q1: return 1;
57 case R2: case D2: case Q2: return 2;
58 case R3: case D3: case Q3: return 3;
59 case R4: case D4: case Q4: return 4;
60 case R5: case D5: case Q5: return 5;
61 case R6: case D6: case Q6: return 6;
62 case R7: case D7: case Q7: return 7;
63 case R8: case D8: case Q8: return 8;
64 case R9: case D9: case Q9: return 9;
65 case R10: case D10: case Q10: return 10;
66 case R11: case D11: case Q11: return 11;
67 case R12: case D12: case Q12: return 12;
68 case SP: case D13: case Q13: return 13;
69 case LR: case D14: case Q14: return 14;
70 case PC: case D15: case Q15: return 15;
89 case S0: case S1: case S2: case S3:
90 case S4: case S5: case S6: case S7:
91 case S8: case S9: case S10: case S11:
92 case S12: case S13: case S14: case S15:
93 case S16: case S17: case S18: case S19:
94 case S20: case S21: case S22: case S23:
95 case S24: case S25: case S26: case S27:
96 case S28: case S29: case S30: case S31: {
100 default: return 0; // Avoid compile time warning.
138 ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
139 const ARMSubtarget &sti)
140 : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
142 FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
146 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
147 static const unsigned CalleeSavedRegs[] = {
148 ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
149 ARM::R7, ARM::R6, ARM::R5, ARM::R4,
151 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
152 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
156 static const unsigned DarwinCalleeSavedRegs[] = {
157 // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
159 ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
160 ARM::R11, ARM::R10, ARM::R8,
162 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
163 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
166 return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
169 const TargetRegisterClass* const *
170 ARMBaseRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
171 static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
172 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
173 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
174 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
176 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
177 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
181 static const TargetRegisterClass * const ThumbCalleeSavedRegClasses[] = {
182 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
183 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::tGPRRegClass,
184 &ARM::tGPRRegClass,&ARM::tGPRRegClass,&ARM::tGPRRegClass,
186 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
187 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
191 static const TargetRegisterClass * const DarwinCalleeSavedRegClasses[] = {
192 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
193 &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
194 &ARM::GPRRegClass, &ARM::GPRRegClass,
196 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
197 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
201 static const TargetRegisterClass * const DarwinThumbCalleeSavedRegClasses[] ={
202 &ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass,
203 &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::GPRRegClass,
204 &ARM::GPRRegClass, &ARM::GPRRegClass,
206 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
207 &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
211 if (STI.isThumb1Only()) {
212 return STI.isTargetDarwin()
213 ? DarwinThumbCalleeSavedRegClasses : ThumbCalleeSavedRegClasses;
215 return STI.isTargetDarwin()
216 ? DarwinCalleeSavedRegClasses : CalleeSavedRegClasses;
219 BitVector ARMBaseRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
220 // FIXME: avoid re-calculating this everytime.
221 BitVector Reserved(getNumRegs());
222 Reserved.set(ARM::SP);
223 Reserved.set(ARM::PC);
224 if (STI.isTargetDarwin() || hasFP(MF))
225 Reserved.set(FramePtr);
226 // Some targets reserve R9.
227 if (STI.isR9Reserved())
228 Reserved.set(ARM::R9);
232 bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
233 unsigned Reg) const {
241 if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
245 return STI.isR9Reserved();
251 const TargetRegisterClass *
252 ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
253 return ARM::GPRRegisterClass;
256 /// getAllocationOrder - Returns the register allocation order for a specified
257 /// register class in the form of a pair of TargetRegisterClass iterators.
258 std::pair<TargetRegisterClass::iterator,TargetRegisterClass::iterator>
259 ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
260 unsigned HintType, unsigned HintReg,
261 const MachineFunction &MF) const {
262 // Alternative register allocation orders when favoring even / odd registers
263 // of register pairs.
265 // No FP, R9 is available.
266 static const unsigned GPREven1[] = {
267 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
268 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
271 static const unsigned GPROdd1[] = {
272 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
273 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
277 // FP is R7, R9 is available.
278 static const unsigned GPREven2[] = {
279 ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
280 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
283 static const unsigned GPROdd2[] = {
284 ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
285 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
289 // FP is R11, R9 is available.
290 static const unsigned GPREven3[] = {
291 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
292 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
295 static const unsigned GPROdd3[] = {
296 ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
297 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
301 // No FP, R9 is not available.
302 static const unsigned GPREven4[] = {
303 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
304 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
307 static const unsigned GPROdd4[] = {
308 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
309 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
313 // FP is R7, R9 is not available.
314 static const unsigned GPREven5[] = {
315 ARM::R0, ARM::R2, ARM::R4, ARM::R10,
316 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
319 static const unsigned GPROdd5[] = {
320 ARM::R1, ARM::R3, ARM::R5, ARM::R11,
321 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
325 // FP is R11, R9 is not available.
326 static const unsigned GPREven6[] = {
327 ARM::R0, ARM::R2, ARM::R4, ARM::R6,
328 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
330 static const unsigned GPROdd6[] = {
331 ARM::R1, ARM::R3, ARM::R5, ARM::R7,
332 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
336 if (HintType == ARMRI::RegPairEven) {
337 if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
338 // It's no longer possible to fulfill this hint. Return the default
340 return std::make_pair(RC->allocation_order_begin(MF),
341 RC->allocation_order_end(MF));
343 if (!STI.isTargetDarwin() && !hasFP(MF)) {
344 if (!STI.isR9Reserved())
345 return std::make_pair(GPREven1,
346 GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
348 return std::make_pair(GPREven4,
349 GPREven4 + (sizeof(GPREven4)/sizeof(unsigned)));
350 } else if (FramePtr == ARM::R7) {
351 if (!STI.isR9Reserved())
352 return std::make_pair(GPREven2,
353 GPREven2 + (sizeof(GPREven2)/sizeof(unsigned)));
355 return std::make_pair(GPREven5,
356 GPREven5 + (sizeof(GPREven5)/sizeof(unsigned)));
357 } else { // FramePtr == ARM::R11
358 if (!STI.isR9Reserved())
359 return std::make_pair(GPREven3,
360 GPREven3 + (sizeof(GPREven3)/sizeof(unsigned)));
362 return std::make_pair(GPREven6,
363 GPREven6 + (sizeof(GPREven6)/sizeof(unsigned)));
365 } else if (HintType == ARMRI::RegPairOdd) {
366 if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
367 // It's no longer possible to fulfill this hint. Return the default
369 return std::make_pair(RC->allocation_order_begin(MF),
370 RC->allocation_order_end(MF));
372 if (!STI.isTargetDarwin() && !hasFP(MF)) {
373 if (!STI.isR9Reserved())
374 return std::make_pair(GPROdd1,
375 GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
377 return std::make_pair(GPROdd4,
378 GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned)));
379 } else if (FramePtr == ARM::R7) {
380 if (!STI.isR9Reserved())
381 return std::make_pair(GPROdd2,
382 GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned)));
384 return std::make_pair(GPROdd5,
385 GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned)));
386 } else { // FramePtr == ARM::R11
387 if (!STI.isR9Reserved())
388 return std::make_pair(GPROdd3,
389 GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned)));
391 return std::make_pair(GPROdd6,
392 GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned)));
395 return std::make_pair(RC->allocation_order_begin(MF),
396 RC->allocation_order_end(MF));
399 /// ResolveRegAllocHint - Resolves the specified register allocation hint
400 /// to a physical register. Returns the physical register if it is successful.
402 ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
403 const MachineFunction &MF) const {
404 if (Reg == 0 || !isPhysicalRegister(Reg))
408 else if (Type == (unsigned)ARMRI::RegPairOdd)
410 return getRegisterPairOdd(Reg, MF);
411 else if (Type == (unsigned)ARMRI::RegPairEven)
413 return getRegisterPairEven(Reg, MF);
418 ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
419 MachineFunction &MF) const {
420 MachineRegisterInfo *MRI = &MF.getRegInfo();
421 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
422 if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
423 Hint.first == (unsigned)ARMRI::RegPairEven) &&
424 Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) {
425 // If 'Reg' is one of the even / odd register pair and it's now changed
426 // (e.g. coalesced) into a different register. The other register of the
427 // pair allocation hint must be updated to reflect the relationship
429 unsigned OtherReg = Hint.second;
430 Hint = MRI->getRegAllocationHint(OtherReg);
431 if (Hint.second == Reg)
432 // Make sure the pair has not already divorced.
433 MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
437 /// hasFP - Return true if the specified function should have a dedicated frame
438 /// pointer register. This is true if the function has variable sized allocas
439 /// or if frame pointer elimination is disabled.
441 bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
442 const MachineFrameInfo *MFI = MF.getFrameInfo();
443 return (NoFramePointerElim ||
444 MFI->hasVarSizedObjects() ||
445 MFI->isFrameAddressTaken());
448 bool ARMBaseRegisterInfo::cannotEliminateFrame(const MachineFunction &MF) const {
449 const MachineFrameInfo *MFI = MF.getFrameInfo();
450 if (NoFramePointerElim && MFI->hasCalls())
452 return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
455 /// estimateStackSize - Estimate and return the size of the frame.
456 static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) {
457 const MachineFrameInfo *FFI = MF.getFrameInfo();
459 for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
460 int FixedOff = -FFI->getObjectOffset(i);
461 if (FixedOff > Offset) Offset = FixedOff;
463 for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
464 if (FFI->isDeadObjectIndex(i))
466 Offset += FFI->getObjectSize(i);
467 unsigned Align = FFI->getObjectAlignment(i);
468 // Adjust to alignment boundary
469 Offset = (Offset+Align-1)/Align*Align;
471 return (unsigned)Offset;
474 /// estimateRSStackSizeLimit - Look at each instruction that references stack
475 /// frames and return the stack size limit beyond which some of these
476 /// instructions will require scratch register during their expansion later.
478 ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
479 unsigned Limit = (1 << 12) - 1;
480 for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
481 for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
483 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
484 if (!I->getOperand(i).isFI()) continue;
486 const TargetInstrDesc &Desc = TII.get(I->getOpcode());
487 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
488 if (AddrMode == ARMII::AddrMode3 ||
489 AddrMode == ARMII::AddrModeT2_i8)
492 if (AddrMode == ARMII::AddrMode5 ||
493 AddrMode == ARMII::AddrModeT2_i8s4)
494 Limit = std::min(Limit, ((1U << 8) - 1) * 4);
496 if (AddrMode == ARMII::AddrModeT2_i12 && hasFP(MF))
497 // When the stack offset is negative, we will end up using
498 // the i8 instructions instead.
500 break; // At most one FI per instruction
509 ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
510 RegScavenger *RS) const {
511 // This tells PEI to spill the FP as if it is any other callee-save register
512 // to take advantage the eliminateFrameIndex machinery. This also ensures it
513 // is spilled in the order specified by getCalleeSavedRegs() to make it easier
514 // to combine multiple loads / stores.
515 bool CanEliminateFrame = true;
516 bool CS1Spilled = false;
517 bool LRSpilled = false;
518 unsigned NumGPRSpills = 0;
519 SmallVector<unsigned, 4> UnspilledCS1GPRs;
520 SmallVector<unsigned, 4> UnspilledCS2GPRs;
521 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
523 // Don't spill FP if the frame can be eliminated. This is determined
524 // by scanning the callee-save registers to see if any is used.
525 const unsigned *CSRegs = getCalleeSavedRegs();
526 const TargetRegisterClass* const *CSRegClasses = getCalleeSavedRegClasses();
527 for (unsigned i = 0; CSRegs[i]; ++i) {
528 unsigned Reg = CSRegs[i];
529 bool Spilled = false;
530 if (MF.getRegInfo().isPhysRegUsed(Reg)) {
531 AFI->setCSRegisterIsSpilled(Reg);
533 CanEliminateFrame = false;
535 // Check alias registers too.
536 for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
537 if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
539 CanEliminateFrame = false;
544 if (CSRegClasses[i] == ARM::GPRRegisterClass ||
545 CSRegClasses[i] == ARM::tGPRRegisterClass) {
549 if (!STI.isTargetDarwin()) {
556 // Keep track if LR and any of R4, R5, R6, and R7 is spilled.
571 if (!STI.isTargetDarwin()) {
572 UnspilledCS1GPRs.push_back(Reg);
582 UnspilledCS1GPRs.push_back(Reg);
585 UnspilledCS2GPRs.push_back(Reg);
592 bool ForceLRSpill = false;
593 if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
594 unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
595 // Force LR to be spilled if the Thumb function size is > 2048. This enables
596 // use of BL to implement far jump. If it turns out that it's not needed
597 // then the branch fix up path will undo it.
598 if (FnSize >= (1 << 11)) {
599 CanEliminateFrame = false;
604 bool ExtraCSSpill = false;
605 if (!CanEliminateFrame || cannotEliminateFrame(MF)) {
606 AFI->setHasStackFrame(true);
608 // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
609 // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
610 if (!LRSpilled && CS1Spilled) {
611 MF.getRegInfo().setPhysRegUsed(ARM::LR);
612 AFI->setCSRegisterIsSpilled(ARM::LR);
614 UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
615 UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
616 ForceLRSpill = false;
620 // Darwin ABI requires FP to point to the stack slot that contains the
622 if (STI.isTargetDarwin() || hasFP(MF)) {
623 MF.getRegInfo().setPhysRegUsed(FramePtr);
627 // If stack and double are 8-byte aligned and we are spilling an odd number
628 // of GPRs. Spill one extra callee save GPR so we won't have to pad between
629 // the integer and double callee save areas.
630 unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
631 if (TargetAlign == 8 && (NumGPRSpills & 1)) {
632 if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
633 for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
634 unsigned Reg = UnspilledCS1GPRs[i];
635 // Don't spill high register if the function is thumb1
636 if (!AFI->isThumb1OnlyFunction() ||
637 isARMLowRegister(Reg) || Reg == ARM::LR) {
638 MF.getRegInfo().setPhysRegUsed(Reg);
639 AFI->setCSRegisterIsSpilled(Reg);
640 if (!isReservedReg(MF, Reg))
645 } else if (!UnspilledCS2GPRs.empty() &&
646 !AFI->isThumb1OnlyFunction()) {
647 unsigned Reg = UnspilledCS2GPRs.front();
648 MF.getRegInfo().setPhysRegUsed(Reg);
649 AFI->setCSRegisterIsSpilled(Reg);
650 if (!isReservedReg(MF, Reg))
655 // Estimate if we might need to scavenge a register at some point in order
656 // to materialize a stack offset. If so, either spill one additional
657 // callee-saved register or reserve a special spill slot to facilitate
658 // register scavenging. Thumb1 needs a spill slot for stack pointer
659 // adjustments also, even when the frame itself is small.
660 if (RS && !ExtraCSSpill) {
661 MachineFrameInfo *MFI = MF.getFrameInfo();
662 // If any of the stack slot references may be out of range of an
663 // immediate offset, make sure a register (or a spill slot) is
664 // available for the register scavenger. Note that if we're indexing
665 // off the frame pointer, the effective stack size is 4 bytes larger
666 // since the FP points to the stack slot of the previous FP.
667 if (estimateStackSize(MF, MFI) + (hasFP(MF) ? 4 : 0)
668 >= estimateRSStackSizeLimit(MF)) {
669 // If any non-reserved CS register isn't spilled, just spill one or two
670 // extra. That should take care of it!
671 unsigned NumExtras = TargetAlign / 4;
672 SmallVector<unsigned, 2> Extras;
673 while (NumExtras && !UnspilledCS1GPRs.empty()) {
674 unsigned Reg = UnspilledCS1GPRs.back();
675 UnspilledCS1GPRs.pop_back();
676 if (!isReservedReg(MF, Reg)) {
677 Extras.push_back(Reg);
681 // For non-Thumb1 functions, also check for hi-reg CS registers
682 if (!AFI->isThumb1OnlyFunction()) {
683 while (NumExtras && !UnspilledCS2GPRs.empty()) {
684 unsigned Reg = UnspilledCS2GPRs.back();
685 UnspilledCS2GPRs.pop_back();
686 if (!isReservedReg(MF, Reg)) {
687 Extras.push_back(Reg);
692 if (Extras.size() && NumExtras == 0) {
693 for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
694 MF.getRegInfo().setPhysRegUsed(Extras[i]);
695 AFI->setCSRegisterIsSpilled(Extras[i]);
697 } else if (!AFI->isThumb1OnlyFunction()) {
698 // note: Thumb1 functions spill to R12, not the stack.
699 // Reserve a slot closest to SP or frame pointer.
700 const TargetRegisterClass *RC = ARM::GPRRegisterClass;
701 RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
702 RC->getAlignment()));
709 MF.getRegInfo().setPhysRegUsed(ARM::LR);
710 AFI->setCSRegisterIsSpilled(ARM::LR);
711 AFI->setLRIsSpilledForFarJump(true);
715 unsigned ARMBaseRegisterInfo::getRARegister() const {
719 unsigned ARMBaseRegisterInfo::getFrameRegister(MachineFunction &MF) const {
720 if (STI.isTargetDarwin() || hasFP(MF))
725 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
726 llvm_unreachable("What is the exception register");
730 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
731 llvm_unreachable("What is the exception handler register");
735 int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
736 return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
739 unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
740 const MachineFunction &MF) const {
743 // Return 0 if either register of the pair is a special register.
752 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6;
754 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
756 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
828 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
829 const MachineFunction &MF) const {
832 // Return 0 if either register of the pair is a special register.
841 return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7;
843 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
845 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
917 /// emitLoadConstPool - Emits a load from constpool to materialize the
918 /// specified immediate.
919 void ARMBaseRegisterInfo::
920 emitLoadConstPool(MachineBasicBlock &MBB,
921 MachineBasicBlock::iterator &MBBI,
923 unsigned DestReg, unsigned SubIdx, int Val,
924 ARMCC::CondCodes Pred,
925 unsigned PredReg) const {
926 MachineFunction &MF = *MBB.getParent();
927 MachineConstantPool *ConstantPool = MF.getConstantPool();
929 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
930 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
932 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
933 .addReg(DestReg, getDefRegState(true), SubIdx)
934 .addConstantPoolIndex(Idx)
935 .addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
938 bool ARMBaseRegisterInfo::
939 requiresRegisterScavenging(const MachineFunction &MF) const {
942 bool ARMBaseRegisterInfo::
943 requiresFrameIndexScavenging(const MachineFunction &MF) const {
947 // hasReservedCallFrame - Under normal circumstances, when a frame pointer is
948 // not required, we reserve argument space for call sites in the function
949 // immediately on entry to the current function. This eliminates the need for
950 // add/sub sp brackets around call sites. Returns true if the call frame is
951 // included as part of the stack frame.
952 bool ARMBaseRegisterInfo::
953 hasReservedCallFrame(MachineFunction &MF) const {
954 const MachineFrameInfo *FFI = MF.getFrameInfo();
955 unsigned CFSize = FFI->getMaxCallFrameSize();
956 // It's not always a good idea to include the call frame as part of the
957 // stack frame. ARM (especially Thumb) has small immediate offset to
958 // address the stack frame. So a large call frame can cause poor codegen
959 // and may even makes it impossible to scavenge a register.
960 if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12
963 return !MF.getFrameInfo()->hasVarSizedObjects();
967 emitSPUpdate(bool isARM,
968 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
969 DebugLoc dl, const ARMBaseInstrInfo &TII,
971 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
973 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
976 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
981 void ARMBaseRegisterInfo::
982 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
983 MachineBasicBlock::iterator I) const {
984 if (!hasReservedCallFrame(MF)) {
985 // If we have alloca, convert as follows:
986 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
987 // ADJCALLSTACKUP -> add, sp, sp, amount
988 MachineInstr *Old = I;
989 DebugLoc dl = Old->getDebugLoc();
990 unsigned Amount = Old->getOperand(0).getImm();
992 // We need to keep the stack aligned properly. To do this, we round the
993 // amount of space needed for the outgoing arguments up to the next
994 // alignment boundary.
995 unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
996 Amount = (Amount+Align-1)/Align*Align;
998 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
999 assert(!AFI->isThumb1OnlyFunction() &&
1000 "This eliminateCallFramePseudoInstr does not suppor Thumb1!");
1001 bool isARM = !AFI->isThumbFunction();
1003 // Replace the pseudo instruction with a new instruction...
1004 unsigned Opc = Old->getOpcode();
1005 ARMCC::CondCodes Pred = (ARMCC::CondCodes)Old->getOperand(1).getImm();
1006 // FIXME: Thumb2 version of ADJCALLSTACKUP and ADJCALLSTACKDOWN?
1007 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
1008 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
1009 unsigned PredReg = Old->getOperand(2).getReg();
1010 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
1012 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
1013 unsigned PredReg = Old->getOperand(3).getReg();
1014 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
1015 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
1023 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1024 int SPAdj, int *Value,
1025 RegScavenger *RS) const {
1027 MachineInstr &MI = *II;
1028 MachineBasicBlock &MBB = *MI.getParent();
1029 MachineFunction &MF = *MBB.getParent();
1030 const MachineFrameInfo *MFI = MF.getFrameInfo();
1031 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1032 assert(!AFI->isThumb1OnlyFunction() &&
1033 "This eliminateFrameIndex does not support Thumb1!");
1035 while (!MI.getOperand(i).isFI()) {
1037 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1040 unsigned FrameReg = ARM::SP;
1041 int FrameIndex = MI.getOperand(i).getIndex();
1042 int Offset = MFI->getObjectOffset(FrameIndex) + MFI->getStackSize() + SPAdj;
1044 if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
1045 Offset -= AFI->getGPRCalleeSavedArea1Offset();
1046 else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
1047 Offset -= AFI->getGPRCalleeSavedArea2Offset();
1048 else if (AFI->isDPRCalleeSavedAreaFrame(FrameIndex))
1049 Offset -= AFI->getDPRCalleeSavedAreaOffset();
1050 else if (hasFP(MF) && AFI->hasStackFrame()) {
1051 assert(SPAdj == 0 && "Unexpected stack offset!");
1052 // Use frame pointer to reference fixed objects unless this is a
1053 // frameless function,
1054 FrameReg = getFrameRegister(MF);
1055 Offset -= AFI->getFramePtrSpillOffset();
1058 // modify MI as necessary to handle as much of 'Offset' as possible
1060 if (!AFI->isThumbFunction())
1061 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1063 assert(AFI->isThumb2Function());
1064 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1069 // If we get here, the immediate doesn't fit into the instruction. We folded
1070 // as much as possible above, handle the rest, providing a register that is
1073 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4) &&
1074 "This code isn't needed if offset already handled!");
1076 unsigned ScratchReg = 0;
1077 int PIdx = MI.findFirstPredOperandIdx();
1078 ARMCC::CondCodes Pred = (PIdx == -1)
1079 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1080 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1082 // Must be addrmode4.
1083 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1085 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1087 if (!AFI->isThumbFunction())
1088 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1089 Offset, Pred, PredReg, TII);
1091 assert(AFI->isThumb2Function());
1092 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1093 Offset, Pred, PredReg, TII);
1095 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
1096 if (!ReuseFrameIndexVals)
1102 /// Move iterator pass the next bunch of callee save load / store ops for
1103 /// the particular spill area (1: integer area 1, 2: integer area 2,
1104 /// 3: fp area, 0: don't care).
1105 static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
1106 MachineBasicBlock::iterator &MBBI,
1107 int Opc1, int Opc2, unsigned Area,
1108 const ARMSubtarget &STI) {
1109 while (MBBI != MBB.end() &&
1110 ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
1111 MBBI->getOperand(1).isFI()) {
1114 unsigned Category = 0;
1115 switch (MBBI->getOperand(0).getReg()) {
1116 case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7:
1120 case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
1121 Category = STI.isTargetDarwin() ? 2 : 1;
1123 case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11:
1124 case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
1131 if (Done || Category != Area)
1139 void ARMBaseRegisterInfo::
1140 emitPrologue(MachineFunction &MF) const {
1141 MachineBasicBlock &MBB = MF.front();
1142 MachineBasicBlock::iterator MBBI = MBB.begin();
1143 MachineFrameInfo *MFI = MF.getFrameInfo();
1144 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1145 assert(!AFI->isThumb1OnlyFunction() &&
1146 "This emitPrologue does not suppor Thumb1!");
1147 bool isARM = !AFI->isThumbFunction();
1148 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1149 unsigned NumBytes = MFI->getStackSize();
1150 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
1151 DebugLoc dl = (MBBI != MBB.end() ?
1152 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
1154 // Determine the sizes of each callee-save spill areas and record which frame
1155 // belongs to which callee-save spill areas.
1156 unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
1157 int FramePtrSpillFI = 0;
1159 // Allocate the vararg register save area. This is not counted in NumBytes.
1161 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
1163 if (!AFI->hasStackFrame()) {
1165 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1169 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
1170 unsigned Reg = CSI[i].getReg();
1171 int FI = CSI[i].getFrameIdx();
1178 if (Reg == FramePtr)
1179 FramePtrSpillFI = FI;
1180 AFI->addGPRCalleeSavedArea1Frame(FI);
1187 if (Reg == FramePtr)
1188 FramePtrSpillFI = FI;
1189 if (STI.isTargetDarwin()) {
1190 AFI->addGPRCalleeSavedArea2Frame(FI);
1193 AFI->addGPRCalleeSavedArea1Frame(FI);
1198 AFI->addDPRCalleeSavedAreaFrame(FI);
1203 // Build the new SUBri to adjust SP for integer callee-save spill area 1.
1204 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
1205 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
1207 // Set FP to point to the stack slot that contains the previous FP.
1208 // For Darwin, FP is R7, which has now been stored in spill area 1.
1209 // Otherwise, if this is not Darwin, all the callee-saved registers go
1210 // into spill area 1, including the FP in R11. In either case, it is
1211 // now safe to emit this assignment.
1212 if (STI.isTargetDarwin() || hasFP(MF)) {
1213 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
1214 MachineInstrBuilder MIB =
1215 BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
1216 .addFrameIndex(FramePtrSpillFI).addImm(0);
1217 AddDefaultCC(AddDefaultPred(MIB));
1220 // Build the new SUBri to adjust SP for integer callee-save spill area 2.
1221 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
1223 // Build the new SUBri to adjust SP for FP callee-save spill area.
1224 movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
1225 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
1227 // Determine starting offsets of spill areas.
1228 unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
1229 unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
1230 unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
1231 AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
1232 AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
1233 AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
1234 AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
1236 NumBytes = DPRCSOffset;
1238 // Insert it after all the callee-save spills.
1239 movePastCSLoadStoreOps(MBB, MBBI, ARM::FSTD, 0, 3, STI);
1240 emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1243 if (STI.isTargetELF() && hasFP(MF)) {
1244 MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
1245 AFI->getFramePtrSpillOffset());
1248 AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
1249 AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
1250 AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
1253 static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
1254 for (unsigned i = 0; CSRegs[i]; ++i)
1255 if (Reg == CSRegs[i])
1260 static bool isCSRestore(MachineInstr *MI,
1261 const ARMBaseInstrInfo &TII,
1262 const unsigned *CSRegs) {
1263 return ((MI->getOpcode() == (int)ARM::FLDD ||
1264 MI->getOpcode() == (int)ARM::LDR ||
1265 MI->getOpcode() == (int)ARM::t2LDRi12) &&
1266 MI->getOperand(1).isFI() &&
1267 isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
1270 void ARMBaseRegisterInfo::
1271 emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
1272 MachineBasicBlock::iterator MBBI = prior(MBB.end());
1273 assert(MBBI->getDesc().isReturn() &&
1274 "Can only insert epilog into returning blocks");
1275 DebugLoc dl = MBBI->getDebugLoc();
1276 MachineFrameInfo *MFI = MF.getFrameInfo();
1277 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1278 assert(!AFI->isThumb1OnlyFunction() &&
1279 "This emitEpilogue does not suppor Thumb1!");
1280 bool isARM = !AFI->isThumbFunction();
1282 unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1283 int NumBytes = (int)MFI->getStackSize();
1285 if (!AFI->hasStackFrame()) {
1287 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1289 // Unwind MBBI to point to first LDR / FLDD.
1290 const unsigned *CSRegs = getCalleeSavedRegs();
1291 if (MBBI != MBB.begin()) {
1294 while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
1295 if (!isCSRestore(MBBI, TII, CSRegs))
1299 // Move SP to start of FP callee save spill area.
1300 NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
1301 AFI->getGPRCalleeSavedArea2Size() +
1302 AFI->getDPRCalleeSavedAreaSize());
1304 // Darwin ABI requires FP to point to the stack slot that contains the
1306 bool HasFP = hasFP(MF);
1307 if ((STI.isTargetDarwin() && NumBytes) || HasFP) {
1308 NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
1309 // Reset SP based on frame pointer only if the stack frame extends beyond
1310 // frame pointer stack slot or target is ELF and the function has FP.
1312 AFI->getGPRCalleeSavedArea2Size() ||
1313 AFI->getDPRCalleeSavedAreaSize() ||
1314 AFI->getDPRCalleeSavedAreaOffset()) {
1317 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1320 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1325 BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
1327 .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
1329 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
1333 } else if (NumBytes)
1334 emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1336 // Move SP to start of integer callee save spill area 2.
1337 movePastCSLoadStoreOps(MBB, MBBI, ARM::FLDD, 0, 3, STI);
1338 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
1340 // Move SP to start of integer callee save spill area 1.
1341 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
1342 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
1344 // Move SP to SP upon entry to the function.
1345 movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
1346 emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
1350 emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
1353 #include "ARMGenRegisterInfo.inc"