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 "ARMFrameLowering.h"
19 #include "ARMInstrInfo.h"
20 #include "ARMMachineFunctionInfo.h"
21 #include "ARMSubtarget.h"
22 #include "llvm/Constants.h"
23 #include "llvm/DerivedTypes.h"
24 #include "llvm/Function.h"
25 #include "llvm/LLVMContext.h"
26 #include "llvm/CodeGen/MachineConstantPool.h"
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineFunction.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineLocation.h"
31 #include "llvm/CodeGen/MachineRegisterInfo.h"
32 #include "llvm/CodeGen/RegisterScavenging.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Target/TargetFrameLowering.h"
37 #include "llvm/Target/TargetMachine.h"
38 #include "llvm/Target/TargetOptions.h"
39 #include "llvm/ADT/BitVector.h"
40 #include "llvm/ADT/SmallVector.h"
41 #include "llvm/Support/CommandLine.h"
46 ForceAllBaseRegAlloc("arm-force-base-reg-alloc", cl::Hidden, cl::init(false),
47 cl::desc("Force use of virtual base registers for stack load/store"));
49 EnableLocalStackAlloc("enable-local-stack-alloc", cl::init(true), cl::Hidden,
50 cl::desc("Enable pre-regalloc stack frame index allocation"));
52 EnableBasePointer("arm-use-base-pointer", cl::Hidden, cl::init(true),
53 cl::desc("Enable use of a base pointer for complex stack frames"));
55 ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
56 const ARMSubtarget &sti)
57 : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
59 FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11),
64 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
65 static const unsigned CalleeSavedRegs[] = {
66 ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
67 ARM::R7, ARM::R6, ARM::R5, ARM::R4,
69 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
70 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
74 static const unsigned DarwinCalleeSavedRegs[] = {
75 // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
77 ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
78 ARM::R11, ARM::R10, ARM::R8,
80 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
81 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
84 return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
87 BitVector ARMBaseRegisterInfo::
88 getReservedRegs(const MachineFunction &MF) const {
89 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
91 // FIXME: avoid re-calculating this every time.
92 BitVector Reserved(getNumRegs());
93 Reserved.set(ARM::SP);
94 Reserved.set(ARM::PC);
95 Reserved.set(ARM::FPSCR);
97 Reserved.set(FramePtr);
98 if (hasBasePointer(MF))
99 Reserved.set(BasePtr);
100 // Some targets reserve R9.
101 if (STI.isR9Reserved())
102 Reserved.set(ARM::R9);
106 bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
107 unsigned Reg) const {
108 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
116 if (hasBasePointer(MF))
121 if (FramePtr == Reg && TFI->hasFP(MF))
125 return STI.isR9Reserved();
131 const TargetRegisterClass *
132 ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
133 const TargetRegisterClass *B,
134 unsigned SubIdx) const {
142 if (A->getSize() == 8) {
143 if (B == &ARM::SPR_8RegClass)
144 return &ARM::DPR_8RegClass;
145 assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
146 if (A == &ARM::DPR_8RegClass)
148 return &ARM::DPR_VFP2RegClass;
151 if (A->getSize() == 16) {
152 if (B == &ARM::SPR_8RegClass)
153 return &ARM::QPR_8RegClass;
154 return &ARM::QPR_VFP2RegClass;
157 if (A->getSize() == 32) {
158 if (B == &ARM::SPR_8RegClass)
159 return 0; // Do not allow coalescing!
160 return &ARM::QQPR_VFP2RegClass;
163 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
164 return 0; // Do not allow coalescing!
171 if (A->getSize() == 16) {
172 if (B == &ARM::DPR_VFP2RegClass)
173 return &ARM::QPR_VFP2RegClass;
174 if (B == &ARM::DPR_8RegClass)
175 return 0; // Do not allow coalescing!
179 if (A->getSize() == 32) {
180 if (B == &ARM::DPR_VFP2RegClass)
181 return &ARM::QQPR_VFP2RegClass;
182 if (B == &ARM::DPR_8RegClass)
183 return 0; // Do not allow coalescing!
187 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
188 if (B != &ARM::DPRRegClass)
189 return 0; // Do not allow coalescing!
196 // D sub-registers of QQQQ registers.
197 if (A->getSize() == 64 && B == &ARM::DPRRegClass)
199 return 0; // Do not allow coalescing!
205 if (A->getSize() == 32) {
206 if (B == &ARM::QPR_VFP2RegClass)
207 return &ARM::QQPR_VFP2RegClass;
208 if (B == &ARM::QPR_8RegClass)
209 return 0; // Do not allow coalescing!
213 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
214 if (B == &ARM::QPRRegClass)
216 return 0; // Do not allow coalescing!
220 // Q sub-registers of QQQQ registers.
221 if (A->getSize() == 64 && B == &ARM::QPRRegClass)
223 return 0; // Do not allow coalescing!
230 ARMBaseRegisterInfo::canCombineSubRegIndices(const TargetRegisterClass *RC,
231 SmallVectorImpl<unsigned> &SubIndices,
232 unsigned &NewSubIdx) const {
234 unsigned Size = RC->getSize() * 8;
238 NewSubIdx = 0; // Whole register.
239 unsigned NumRegs = SubIndices.size();
241 // 8 D registers -> 1 QQQQ register.
242 return (Size == 512 &&
243 SubIndices[0] == ARM::dsub_0 &&
244 SubIndices[1] == ARM::dsub_1 &&
245 SubIndices[2] == ARM::dsub_2 &&
246 SubIndices[3] == ARM::dsub_3 &&
247 SubIndices[4] == ARM::dsub_4 &&
248 SubIndices[5] == ARM::dsub_5 &&
249 SubIndices[6] == ARM::dsub_6 &&
250 SubIndices[7] == ARM::dsub_7);
251 } else if (NumRegs == 4) {
252 if (SubIndices[0] == ARM::qsub_0) {
253 // 4 Q registers -> 1 QQQQ register.
254 return (Size == 512 &&
255 SubIndices[1] == ARM::qsub_1 &&
256 SubIndices[2] == ARM::qsub_2 &&
257 SubIndices[3] == ARM::qsub_3);
258 } else if (SubIndices[0] == ARM::dsub_0) {
259 // 4 D registers -> 1 QQ register.
261 SubIndices[1] == ARM::dsub_1 &&
262 SubIndices[2] == ARM::dsub_2 &&
263 SubIndices[3] == ARM::dsub_3) {
265 NewSubIdx = ARM::qqsub_0;
268 } else if (SubIndices[0] == ARM::dsub_4) {
269 // 4 D registers -> 1 QQ register (2nd).
271 SubIndices[1] == ARM::dsub_5 &&
272 SubIndices[2] == ARM::dsub_6 &&
273 SubIndices[3] == ARM::dsub_7) {
274 NewSubIdx = ARM::qqsub_1;
277 } else if (SubIndices[0] == ARM::ssub_0) {
278 // 4 S registers -> 1 Q register.
280 SubIndices[1] == ARM::ssub_1 &&
281 SubIndices[2] == ARM::ssub_2 &&
282 SubIndices[3] == ARM::ssub_3) {
284 NewSubIdx = ARM::qsub_0;
288 } else if (NumRegs == 2) {
289 if (SubIndices[0] == ARM::qsub_0) {
290 // 2 Q registers -> 1 QQ register.
291 if (Size >= 256 && SubIndices[1] == ARM::qsub_1) {
293 NewSubIdx = ARM::qqsub_0;
296 } else if (SubIndices[0] == ARM::qsub_2) {
297 // 2 Q registers -> 1 QQ register (2nd).
298 if (Size == 512 && SubIndices[1] == ARM::qsub_3) {
299 NewSubIdx = ARM::qqsub_1;
302 } else if (SubIndices[0] == ARM::dsub_0) {
303 // 2 D registers -> 1 Q register.
304 if (Size >= 128 && SubIndices[1] == ARM::dsub_1) {
306 NewSubIdx = ARM::qsub_0;
309 } else if (SubIndices[0] == ARM::dsub_2) {
310 // 2 D registers -> 1 Q register (2nd).
311 if (Size >= 256 && SubIndices[1] == ARM::dsub_3) {
312 NewSubIdx = ARM::qsub_1;
315 } else if (SubIndices[0] == ARM::dsub_4) {
316 // 2 D registers -> 1 Q register (3rd).
317 if (Size == 512 && SubIndices[1] == ARM::dsub_5) {
318 NewSubIdx = ARM::qsub_2;
321 } else if (SubIndices[0] == ARM::dsub_6) {
322 // 2 D registers -> 1 Q register (3rd).
323 if (Size == 512 && SubIndices[1] == ARM::dsub_7) {
324 NewSubIdx = ARM::qsub_3;
327 } else if (SubIndices[0] == ARM::ssub_0) {
328 // 2 S registers -> 1 D register.
329 if (SubIndices[1] == ARM::ssub_1) {
331 NewSubIdx = ARM::dsub_0;
334 } else if (SubIndices[0] == ARM::ssub_2) {
335 // 2 S registers -> 1 D register (2nd).
336 if (Size >= 128 && SubIndices[1] == ARM::ssub_3) {
337 NewSubIdx = ARM::dsub_1;
345 const TargetRegisterClass*
346 ARMBaseRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC)
348 const TargetRegisterClass *Super = RC;
349 TargetRegisterClass::sc_iterator I = RC->superclasses_begin();
351 switch (Super->getID()) {
352 case ARM::GPRRegClassID:
353 case ARM::SPRRegClassID:
354 case ARM::DPRRegClassID:
355 case ARM::QPRRegClassID:
356 case ARM::QQPRRegClassID:
357 case ARM::QQQQPRRegClassID:
365 const TargetRegisterClass *
366 ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
367 return ARM::GPRRegisterClass;
371 ARMBaseRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
372 MachineFunction &MF) const {
373 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
375 switch (RC->getID()) {
378 case ARM::tGPRRegClassID:
379 return TFI->hasFP(MF) ? 4 : 5;
380 case ARM::GPRRegClassID: {
381 unsigned FP = TFI->hasFP(MF) ? 1 : 0;
382 return 10 - FP - (STI.isR9Reserved() ? 1 : 0);
384 case ARM::SPRRegClassID: // Currently not used as 'rep' register class.
385 case ARM::DPRRegClassID:
390 /// getRawAllocationOrder - Returns the register allocation order for a
391 /// specified register class with a target-dependent hint.
393 ARMBaseRegisterInfo::getRawAllocationOrder(const TargetRegisterClass *RC,
394 unsigned HintType, unsigned HintReg,
395 const MachineFunction &MF) const {
396 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
397 // Alternative register allocation orders when favoring even / odd registers
398 // of register pairs.
400 // No FP, R9 is available.
401 static const unsigned GPREven1[] = {
402 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
403 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
406 static const unsigned GPROdd1[] = {
407 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
408 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
412 // FP is R7, R9 is available.
413 static const unsigned GPREven2[] = {
414 ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
415 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
418 static const unsigned GPROdd2[] = {
419 ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
420 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
424 // FP is R11, R9 is available.
425 static const unsigned GPREven3[] = {
426 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
427 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
430 static const unsigned GPROdd3[] = {
431 ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
432 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
436 // No FP, R9 is not available.
437 static const unsigned GPREven4[] = {
438 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
439 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
442 static const unsigned GPROdd4[] = {
443 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
444 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
448 // FP is R7, R9 is not available.
449 static const unsigned GPREven5[] = {
450 ARM::R0, ARM::R2, ARM::R4, ARM::R10,
451 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
454 static const unsigned GPROdd5[] = {
455 ARM::R1, ARM::R3, ARM::R5, ARM::R11,
456 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
460 // FP is R11, R9 is not available.
461 static const unsigned GPREven6[] = {
462 ARM::R0, ARM::R2, ARM::R4, ARM::R6,
463 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
465 static const unsigned GPROdd6[] = {
466 ARM::R1, ARM::R3, ARM::R5, ARM::R7,
467 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
470 // We only support even/odd hints for GPR and rGPR.
471 if (RC != ARM::GPRRegisterClass && RC != ARM::rGPRRegisterClass)
472 return RC->getRawAllocationOrder(MF);
474 if (HintType == ARMRI::RegPairEven) {
475 if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
476 // It's no longer possible to fulfill this hint. Return the default
478 return RC->getRawAllocationOrder(MF);
480 if (!TFI->hasFP(MF)) {
481 if (!STI.isR9Reserved())
482 return ArrayRef<unsigned>(GPREven1);
484 return ArrayRef<unsigned>(GPREven4);
485 } else if (FramePtr == ARM::R7) {
486 if (!STI.isR9Reserved())
487 return ArrayRef<unsigned>(GPREven2);
489 return ArrayRef<unsigned>(GPREven5);
490 } else { // FramePtr == ARM::R11
491 if (!STI.isR9Reserved())
492 return ArrayRef<unsigned>(GPREven3);
494 return ArrayRef<unsigned>(GPREven6);
496 } else if (HintType == ARMRI::RegPairOdd) {
497 if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
498 // It's no longer possible to fulfill this hint. Return the default
500 return RC->getRawAllocationOrder(MF);
502 if (!TFI->hasFP(MF)) {
503 if (!STI.isR9Reserved())
504 return ArrayRef<unsigned>(GPROdd1);
506 return ArrayRef<unsigned>(GPROdd4);
507 } else if (FramePtr == ARM::R7) {
508 if (!STI.isR9Reserved())
509 return ArrayRef<unsigned>(GPROdd2);
511 return ArrayRef<unsigned>(GPROdd5);
512 } else { // FramePtr == ARM::R11
513 if (!STI.isR9Reserved())
514 return ArrayRef<unsigned>(GPROdd3);
516 return ArrayRef<unsigned>(GPROdd6);
519 return RC->getRawAllocationOrder(MF);
522 /// ResolveRegAllocHint - Resolves the specified register allocation hint
523 /// to a physical register. Returns the physical register if it is successful.
525 ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
526 const MachineFunction &MF) const {
527 if (Reg == 0 || !isPhysicalRegister(Reg))
531 else if (Type == (unsigned)ARMRI::RegPairOdd)
533 return getRegisterPairOdd(Reg, MF);
534 else if (Type == (unsigned)ARMRI::RegPairEven)
536 return getRegisterPairEven(Reg, MF);
541 ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
542 MachineFunction &MF) const {
543 MachineRegisterInfo *MRI = &MF.getRegInfo();
544 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
545 if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
546 Hint.first == (unsigned)ARMRI::RegPairEven) &&
547 TargetRegisterInfo::isVirtualRegister(Hint.second)) {
548 // If 'Reg' is one of the even / odd register pair and it's now changed
549 // (e.g. coalesced) into a different register. The other register of the
550 // pair allocation hint must be updated to reflect the relationship
552 unsigned OtherReg = Hint.second;
553 Hint = MRI->getRegAllocationHint(OtherReg);
554 if (Hint.second == Reg)
555 // Make sure the pair has not already divorced.
556 MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
561 ARMBaseRegisterInfo::avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
562 // CortexA9 has a Write-after-write hazard for NEON registers.
563 if (!STI.isCortexA9())
566 switch (RC->getID()) {
567 case ARM::DPRRegClassID:
568 case ARM::DPR_8RegClassID:
569 case ARM::DPR_VFP2RegClassID:
570 case ARM::QPRRegClassID:
571 case ARM::QPR_8RegClassID:
572 case ARM::QPR_VFP2RegClassID:
573 case ARM::SPRRegClassID:
574 case ARM::SPR_8RegClassID:
575 // Avoid reusing S, D, and Q registers.
576 // Don't increase register pressure for QQ and QQQQ.
583 bool ARMBaseRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
584 const MachineFrameInfo *MFI = MF.getFrameInfo();
585 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
587 if (!EnableBasePointer)
590 if (needsStackRealignment(MF) && MFI->hasVarSizedObjects())
593 // Thumb has trouble with negative offsets from the FP. Thumb2 has a limited
594 // negative range for ldr/str (255), and thumb1 is positive offsets only.
595 // It's going to be better to use the SP or Base Pointer instead. When there
596 // are variable sized objects, we can't reference off of the SP, so we
597 // reserve a Base Pointer.
598 if (AFI->isThumbFunction() && MFI->hasVarSizedObjects()) {
599 // Conservatively estimate whether the negative offset from the frame
600 // pointer will be sufficient to reach. If a function has a smallish
601 // frame, it's less likely to have lots of spills and callee saved
602 // space, so it's all more likely to be within range of the frame pointer.
603 // If it's wrong, the scavenger will still enable access to work, it just
605 if (AFI->isThumb2Function() && MFI->getLocalFrameSize() < 128)
613 bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
614 const MachineFrameInfo *MFI = MF.getFrameInfo();
615 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
616 // We can't realign the stack if:
617 // 1. Dynamic stack realignment is explicitly disabled,
618 // 2. This is a Thumb1 function (it's not useful, so we don't bother), or
619 // 3. There are VLAs in the function and the base pointer is disabled.
620 return (RealignStack && !AFI->isThumb1OnlyFunction() &&
621 (!MFI->hasVarSizedObjects() || EnableBasePointer));
624 bool ARMBaseRegisterInfo::
625 needsStackRealignment(const MachineFunction &MF) const {
626 const MachineFrameInfo *MFI = MF.getFrameInfo();
627 const Function *F = MF.getFunction();
628 unsigned StackAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
629 bool requiresRealignment = ((MFI->getLocalFrameMaxAlign() > StackAlign) ||
630 F->hasFnAttr(Attribute::StackAlignment));
632 return requiresRealignment && canRealignStack(MF);
635 bool ARMBaseRegisterInfo::
636 cannotEliminateFrame(const MachineFunction &MF) const {
637 const MachineFrameInfo *MFI = MF.getFrameInfo();
638 if (DisableFramePointerElim(MF) && MFI->adjustsStack())
640 return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
641 || needsStackRealignment(MF);
644 unsigned ARMBaseRegisterInfo::getRARegister() const {
649 ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
650 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
657 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
658 llvm_unreachable("What is the exception register");
662 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
663 llvm_unreachable("What is the exception handler register");
667 int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
668 return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
671 int ARMBaseRegisterInfo::getLLVMRegNum(unsigned DwarfRegNo, bool isEH) const {
672 return ARMGenRegisterInfo::getLLVMRegNumFull(DwarfRegNo,0);
675 unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
676 const MachineFunction &MF) const {
679 // Return 0 if either register of the pair is a special register.
688 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
691 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
693 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
765 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
766 const MachineFunction &MF) const {
769 // Return 0 if either register of the pair is a special register.
778 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
781 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
783 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
855 /// emitLoadConstPool - Emits a load from constpool to materialize the
856 /// specified immediate.
857 void ARMBaseRegisterInfo::
858 emitLoadConstPool(MachineBasicBlock &MBB,
859 MachineBasicBlock::iterator &MBBI,
861 unsigned DestReg, unsigned SubIdx, int Val,
862 ARMCC::CondCodes Pred,
863 unsigned PredReg, unsigned MIFlags) const {
864 MachineFunction &MF = *MBB.getParent();
865 MachineConstantPool *ConstantPool = MF.getConstantPool();
867 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
868 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
870 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
871 .addReg(DestReg, getDefRegState(true), SubIdx)
872 .addConstantPoolIndex(Idx)
873 .addImm(0).addImm(Pred).addReg(PredReg)
874 .setMIFlags(MIFlags);
877 bool ARMBaseRegisterInfo::
878 requiresRegisterScavenging(const MachineFunction &MF) const {
882 bool ARMBaseRegisterInfo::
883 requiresFrameIndexScavenging(const MachineFunction &MF) const {
887 bool ARMBaseRegisterInfo::
888 requiresVirtualBaseRegisters(const MachineFunction &MF) const {
889 return EnableLocalStackAlloc;
893 emitSPUpdate(bool isARM,
894 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
895 DebugLoc dl, const ARMBaseInstrInfo &TII,
897 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
899 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
902 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
907 void ARMBaseRegisterInfo::
908 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
909 MachineBasicBlock::iterator I) const {
910 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
911 if (!TFI->hasReservedCallFrame(MF)) {
912 // If we have alloca, convert as follows:
913 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
914 // ADJCALLSTACKUP -> add, sp, sp, amount
915 MachineInstr *Old = I;
916 DebugLoc dl = Old->getDebugLoc();
917 unsigned Amount = Old->getOperand(0).getImm();
919 // We need to keep the stack aligned properly. To do this, we round the
920 // amount of space needed for the outgoing arguments up to the next
921 // alignment boundary.
922 unsigned Align = TFI->getStackAlignment();
923 Amount = (Amount+Align-1)/Align*Align;
925 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
926 assert(!AFI->isThumb1OnlyFunction() &&
927 "This eliminateCallFramePseudoInstr does not support Thumb1!");
928 bool isARM = !AFI->isThumbFunction();
930 // Replace the pseudo instruction with a new instruction...
931 unsigned Opc = Old->getOpcode();
932 int PIdx = Old->findFirstPredOperandIdx();
933 ARMCC::CondCodes Pred = (PIdx == -1)
934 ? ARMCC::AL : (ARMCC::CondCodes)Old->getOperand(PIdx).getImm();
935 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
936 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
937 unsigned PredReg = Old->getOperand(2).getReg();
938 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
940 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
941 unsigned PredReg = Old->getOperand(3).getReg();
942 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
943 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
950 int64_t ARMBaseRegisterInfo::
951 getFrameIndexInstrOffset(const MachineInstr *MI, int Idx) const {
952 const TargetInstrDesc &Desc = MI->getDesc();
953 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
954 int64_t InstrOffs = 0;;
958 case ARMII::AddrModeT2_i8:
959 case ARMII::AddrModeT2_i12:
960 case ARMII::AddrMode_i12:
961 InstrOffs = MI->getOperand(Idx+1).getImm();
964 case ARMII::AddrMode5: {
966 const MachineOperand &OffOp = MI->getOperand(Idx+1);
967 InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
968 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
969 InstrOffs = -InstrOffs;
973 case ARMII::AddrMode2: {
975 InstrOffs = ARM_AM::getAM2Offset(MI->getOperand(ImmIdx).getImm());
976 if (ARM_AM::getAM2Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
977 InstrOffs = -InstrOffs;
980 case ARMII::AddrMode3: {
982 InstrOffs = ARM_AM::getAM3Offset(MI->getOperand(ImmIdx).getImm());
983 if (ARM_AM::getAM3Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
984 InstrOffs = -InstrOffs;
987 case ARMII::AddrModeT1_s: {
989 InstrOffs = MI->getOperand(ImmIdx).getImm();
994 llvm_unreachable("Unsupported addressing mode!");
998 return InstrOffs * Scale;
1001 /// needsFrameBaseReg - Returns true if the instruction's frame index
1002 /// reference would be better served by a base register other than FP
1003 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
1004 /// references it should create new base registers for.
1005 bool ARMBaseRegisterInfo::
1006 needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
1007 for (unsigned i = 0; !MI->getOperand(i).isFI(); ++i) {
1008 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
1011 // It's the load/store FI references that cause issues, as it can be difficult
1012 // to materialize the offset if it won't fit in the literal field. Estimate
1013 // based on the size of the local frame and some conservative assumptions
1014 // about the rest of the stack frame (note, this is pre-regalloc, so
1015 // we don't know everything for certain yet) whether this offset is likely
1016 // to be out of range of the immediate. Return true if so.
1018 // We only generate virtual base registers for loads and stores, so
1019 // return false for everything else.
1020 unsigned Opc = MI->getOpcode();
1022 case ARM::LDRi12: case ARM::LDRH: case ARM::LDRBi12:
1023 case ARM::STRi12: case ARM::STRH: case ARM::STRBi12:
1024 case ARM::t2LDRi12: case ARM::t2LDRi8:
1025 case ARM::t2STRi12: case ARM::t2STRi8:
1026 case ARM::VLDRS: case ARM::VLDRD:
1027 case ARM::VSTRS: case ARM::VSTRD:
1028 case ARM::tSTRspi: case ARM::tLDRspi:
1029 if (ForceAllBaseRegAlloc)
1036 // Without a virtual base register, if the function has variable sized
1037 // objects, all fixed-size local references will be via the frame pointer,
1038 // Approximate the offset and see if it's legal for the instruction.
1039 // Note that the incoming offset is based on the SP value at function entry,
1040 // so it'll be negative.
1041 MachineFunction &MF = *MI->getParent()->getParent();
1042 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
1043 MachineFrameInfo *MFI = MF.getFrameInfo();
1044 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1046 // Estimate an offset from the frame pointer.
1047 // Conservatively assume all callee-saved registers get pushed. R4-R6
1048 // will be earlier than the FP, so we ignore those.
1050 int64_t FPOffset = Offset - 8;
1051 // ARM and Thumb2 functions also need to consider R8-R11 and D8-D15
1052 if (!AFI->isThumbFunction() || !AFI->isThumb1OnlyFunction())
1054 // Estimate an offset from the stack pointer.
1055 // The incoming offset is relating to the SP at the start of the function,
1056 // but when we access the local it'll be relative to the SP after local
1057 // allocation, so adjust our SP-relative offset by that allocation size.
1059 Offset += MFI->getLocalFrameSize();
1060 // Assume that we'll have at least some spill slots allocated.
1061 // FIXME: This is a total SWAG number. We should run some statistics
1062 // and pick a real one.
1063 Offset += 128; // 128 bytes of spill slots
1065 // If there is a frame pointer, try using it.
1066 // The FP is only available if there is no dynamic realignment. We
1067 // don't know for sure yet whether we'll need that, so we guess based
1068 // on whether there are any local variables that would trigger it.
1069 unsigned StackAlign = TFI->getStackAlignment();
1070 if (TFI->hasFP(MF) &&
1071 !((MFI->getLocalFrameMaxAlign() > StackAlign) && canRealignStack(MF))) {
1072 if (isFrameOffsetLegal(MI, FPOffset))
1075 // If we can reference via the stack pointer, try that.
1076 // FIXME: This (and the code that resolves the references) can be improved
1077 // to only disallow SP relative references in the live range of
1078 // the VLA(s). In practice, it's unclear how much difference that
1079 // would make, but it may be worth doing.
1080 if (!MFI->hasVarSizedObjects() && isFrameOffsetLegal(MI, Offset))
1083 // The offset likely isn't legal, we want to allocate a virtual base register.
1087 /// materializeFrameBaseRegister - Insert defining instruction(s) for BaseReg to
1088 /// be a pointer to FrameIdx at the beginning of the basic block.
1089 void ARMBaseRegisterInfo::
1090 materializeFrameBaseRegister(MachineBasicBlock *MBB,
1091 unsigned BaseReg, int FrameIdx,
1092 int64_t Offset) const {
1093 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
1094 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri :
1095 (AFI->isThumb1OnlyFunction() ? ARM::tADDrSPi : ARM::t2ADDri);
1097 MachineBasicBlock::iterator Ins = MBB->begin();
1098 DebugLoc DL; // Defaults to "unknown"
1099 if (Ins != MBB->end())
1100 DL = Ins->getDebugLoc();
1102 const TargetInstrDesc &TID = TII.get(ADDriOpc);
1103 MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
1104 MRI.constrainRegClass(BaseReg, TID.OpInfo[0].getRegClass(this));
1106 MachineInstrBuilder MIB = BuildMI(*MBB, Ins, DL, TID, BaseReg)
1107 .addFrameIndex(FrameIdx).addImm(Offset);
1109 if (!AFI->isThumb1OnlyFunction())
1110 AddDefaultCC(AddDefaultPred(MIB));
1114 ARMBaseRegisterInfo::resolveFrameIndex(MachineBasicBlock::iterator I,
1115 unsigned BaseReg, int64_t Offset) const {
1116 MachineInstr &MI = *I;
1117 MachineBasicBlock &MBB = *MI.getParent();
1118 MachineFunction &MF = *MBB.getParent();
1119 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1120 int Off = Offset; // ARM doesn't need the general 64-bit offsets
1123 assert(!AFI->isThumb1OnlyFunction() &&
1124 "This resolveFrameIndex does not support Thumb1!");
1126 while (!MI.getOperand(i).isFI()) {
1128 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1131 if (!AFI->isThumbFunction())
1132 Done = rewriteARMFrameIndex(MI, i, BaseReg, Off, TII);
1134 assert(AFI->isThumb2Function());
1135 Done = rewriteT2FrameIndex(MI, i, BaseReg, Off, TII);
1137 assert (Done && "Unable to resolve frame index!");
1140 bool ARMBaseRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
1141 int64_t Offset) const {
1142 const TargetInstrDesc &Desc = MI->getDesc();
1143 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
1146 while (!MI->getOperand(i).isFI()) {
1148 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
1151 // AddrMode4 and AddrMode6 cannot handle any offset.
1152 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
1155 unsigned NumBits = 0;
1157 bool isSigned = true;
1159 case ARMII::AddrModeT2_i8:
1160 case ARMII::AddrModeT2_i12:
1161 // i8 supports only negative, and i12 supports only positive, so
1162 // based on Offset sign, consider the appropriate instruction
1171 case ARMII::AddrMode5:
1172 // VFP address mode.
1176 case ARMII::AddrMode_i12:
1177 case ARMII::AddrMode2:
1180 case ARMII::AddrMode3:
1183 case ARMII::AddrModeT1_s:
1189 llvm_unreachable("Unsupported addressing mode!");
1193 Offset += getFrameIndexInstrOffset(MI, i);
1194 // Make sure the offset is encodable for instructions that scale the
1196 if ((Offset & (Scale-1)) != 0)
1199 if (isSigned && Offset < 0)
1202 unsigned Mask = (1 << NumBits) - 1;
1203 if ((unsigned)Offset <= Mask * Scale)
1210 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1211 int SPAdj, RegScavenger *RS) const {
1213 MachineInstr &MI = *II;
1214 MachineBasicBlock &MBB = *MI.getParent();
1215 MachineFunction &MF = *MBB.getParent();
1216 const ARMFrameLowering *TFI =
1217 static_cast<const ARMFrameLowering*>(MF.getTarget().getFrameLowering());
1218 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1219 assert(!AFI->isThumb1OnlyFunction() &&
1220 "This eliminateFrameIndex does not support Thumb1!");
1222 while (!MI.getOperand(i).isFI()) {
1224 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1227 int FrameIndex = MI.getOperand(i).getIndex();
1230 int Offset = TFI->ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
1232 // Special handling of dbg_value instructions.
1233 if (MI.isDebugValue()) {
1234 MI.getOperand(i). ChangeToRegister(FrameReg, false /*isDef*/);
1235 MI.getOperand(i+1).ChangeToImmediate(Offset);
1239 // Modify MI as necessary to handle as much of 'Offset' as possible
1241 if (!AFI->isThumbFunction())
1242 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1244 assert(AFI->isThumb2Function());
1245 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1250 // If we get here, the immediate doesn't fit into the instruction. We folded
1251 // as much as possible above, handle the rest, providing a register that is
1254 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1255 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1256 "This code isn't needed if offset already handled!");
1258 unsigned ScratchReg = 0;
1259 int PIdx = MI.findFirstPredOperandIdx();
1260 ARMCC::CondCodes Pred = (PIdx == -1)
1261 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1262 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1264 // Must be addrmode4/6.
1265 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1267 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1268 if (!AFI->isThumbFunction())
1269 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1270 Offset, Pred, PredReg, TII);
1272 assert(AFI->isThumb2Function());
1273 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1274 Offset, Pred, PredReg, TII);
1276 // Update the original instruction to use the scratch register.
1277 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
1278 if (MI.getOpcode() == ARM::t2ADDrSPi)
1279 MI.setDesc(TII.get(ARM::t2ADDri));
1280 else if (MI.getOpcode() == ARM::t2SUBrSPi)
1281 MI.setDesc(TII.get(ARM::t2SUBri));
1285 #include "ARMGenRegisterInfo.inc"