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 "ARMBaseInstrInfo.h"
16 #include "ARMBaseRegisterInfo.h"
17 #include "ARMFrameLowering.h"
18 #include "ARMInstrInfo.h"
19 #include "ARMMachineFunctionInfo.h"
20 #include "ARMSubtarget.h"
21 #include "MCTargetDesc/ARMAddressingModes.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/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/TargetFrameLowering.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"
42 #define GET_REGINFO_TARGET_DESC
43 #include "ARMGenRegisterInfo.inc"
48 ForceAllBaseRegAlloc("arm-force-base-reg-alloc", cl::Hidden, cl::init(false),
49 cl::desc("Force use of virtual base registers for stack load/store"));
51 EnableLocalStackAlloc("enable-local-stack-alloc", cl::init(true), cl::Hidden,
52 cl::desc("Enable pre-regalloc stack frame index allocation"));
54 EnableBasePointer("arm-use-base-pointer", cl::Hidden, cl::init(true),
55 cl::desc("Enable use of a base pointer for complex stack frames"));
57 ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
58 const ARMSubtarget &sti)
59 : ARMGenRegisterInfo(ARM::LR), TII(tii), STI(sti),
60 FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11),
65 ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
66 static const unsigned CalleeSavedRegs[] = {
67 ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
68 ARM::R7, ARM::R6, ARM::R5, ARM::R4,
70 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
71 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
75 static const unsigned DarwinCalleeSavedRegs[] = {
76 // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
78 ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
79 ARM::R11, ARM::R10, ARM::R8,
81 ARM::D15, ARM::D14, ARM::D13, ARM::D12,
82 ARM::D11, ARM::D10, ARM::D9, ARM::D8,
85 return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
88 BitVector ARMBaseRegisterInfo::
89 getReservedRegs(const MachineFunction &MF) const {
90 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
92 // FIXME: avoid re-calculating this every time.
93 BitVector Reserved(getNumRegs());
94 Reserved.set(ARM::SP);
95 Reserved.set(ARM::PC);
96 Reserved.set(ARM::FPSCR);
98 Reserved.set(FramePtr);
99 if (hasBasePointer(MF))
100 Reserved.set(BasePtr);
101 // Some targets reserve R9.
102 if (STI.isR9Reserved())
103 Reserved.set(ARM::R9);
104 // Reserve D16-D31 if the subtarget doesn't support them.
105 if (!STI.hasVFP3() || STI.hasD16()) {
106 assert(ARM::D31 == ARM::D16 + 15);
107 for (unsigned i = 0; i != 16; ++i)
108 Reserved.set(ARM::D16 + i);
113 bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
114 unsigned Reg) const {
115 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
123 if (hasBasePointer(MF))
128 if (FramePtr == Reg && TFI->hasFP(MF))
132 return STI.isR9Reserved();
138 const TargetRegisterClass *
139 ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
140 const TargetRegisterClass *B,
141 unsigned SubIdx) const {
149 if (A->getSize() == 8) {
150 if (B == &ARM::SPR_8RegClass)
151 return &ARM::DPR_8RegClass;
152 assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
153 if (A == &ARM::DPR_8RegClass)
155 return &ARM::DPR_VFP2RegClass;
158 if (A->getSize() == 16) {
159 if (B == &ARM::SPR_8RegClass)
160 return &ARM::QPR_8RegClass;
161 return &ARM::QPR_VFP2RegClass;
164 if (A->getSize() == 32) {
165 if (B == &ARM::SPR_8RegClass)
166 return 0; // Do not allow coalescing!
167 return &ARM::QQPR_VFP2RegClass;
170 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
171 return 0; // Do not allow coalescing!
178 if (A->getSize() == 16) {
179 if (B == &ARM::DPR_VFP2RegClass)
180 return &ARM::QPR_VFP2RegClass;
181 if (B == &ARM::DPR_8RegClass)
182 return 0; // Do not allow coalescing!
186 if (A->getSize() == 32) {
187 if (B == &ARM::DPR_VFP2RegClass)
188 return &ARM::QQPR_VFP2RegClass;
189 if (B == &ARM::DPR_8RegClass)
190 return 0; // Do not allow coalescing!
194 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
195 if (B != &ARM::DPRRegClass)
196 return 0; // Do not allow coalescing!
203 // D sub-registers of QQQQ registers.
204 if (A->getSize() == 64 && B == &ARM::DPRRegClass)
206 return 0; // Do not allow coalescing!
212 if (A->getSize() == 32) {
213 if (B == &ARM::QPR_VFP2RegClass)
214 return &ARM::QQPR_VFP2RegClass;
215 if (B == &ARM::QPR_8RegClass)
216 return 0; // Do not allow coalescing!
220 assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
221 if (B == &ARM::QPRRegClass)
223 return 0; // Do not allow coalescing!
227 // Q sub-registers of QQQQ registers.
228 if (A->getSize() == 64 && B == &ARM::QPRRegClass)
230 return 0; // Do not allow coalescing!
237 ARMBaseRegisterInfo::canCombineSubRegIndices(const TargetRegisterClass *RC,
238 SmallVectorImpl<unsigned> &SubIndices,
239 unsigned &NewSubIdx) const {
241 unsigned Size = RC->getSize() * 8;
245 NewSubIdx = 0; // Whole register.
246 unsigned NumRegs = SubIndices.size();
248 // 8 D registers -> 1 QQQQ register.
249 return (Size == 512 &&
250 SubIndices[0] == ARM::dsub_0 &&
251 SubIndices[1] == ARM::dsub_1 &&
252 SubIndices[2] == ARM::dsub_2 &&
253 SubIndices[3] == ARM::dsub_3 &&
254 SubIndices[4] == ARM::dsub_4 &&
255 SubIndices[5] == ARM::dsub_5 &&
256 SubIndices[6] == ARM::dsub_6 &&
257 SubIndices[7] == ARM::dsub_7);
258 } else if (NumRegs == 4) {
259 if (SubIndices[0] == ARM::qsub_0) {
260 // 4 Q registers -> 1 QQQQ register.
261 return (Size == 512 &&
262 SubIndices[1] == ARM::qsub_1 &&
263 SubIndices[2] == ARM::qsub_2 &&
264 SubIndices[3] == ARM::qsub_3);
265 } else if (SubIndices[0] == ARM::dsub_0) {
266 // 4 D registers -> 1 QQ register.
268 SubIndices[1] == ARM::dsub_1 &&
269 SubIndices[2] == ARM::dsub_2 &&
270 SubIndices[3] == ARM::dsub_3) {
272 NewSubIdx = ARM::qqsub_0;
275 } else if (SubIndices[0] == ARM::dsub_4) {
276 // 4 D registers -> 1 QQ register (2nd).
278 SubIndices[1] == ARM::dsub_5 &&
279 SubIndices[2] == ARM::dsub_6 &&
280 SubIndices[3] == ARM::dsub_7) {
281 NewSubIdx = ARM::qqsub_1;
284 } else if (SubIndices[0] == ARM::ssub_0) {
285 // 4 S registers -> 1 Q register.
287 SubIndices[1] == ARM::ssub_1 &&
288 SubIndices[2] == ARM::ssub_2 &&
289 SubIndices[3] == ARM::ssub_3) {
291 NewSubIdx = ARM::qsub_0;
295 } else if (NumRegs == 2) {
296 if (SubIndices[0] == ARM::qsub_0) {
297 // 2 Q registers -> 1 QQ register.
298 if (Size >= 256 && SubIndices[1] == ARM::qsub_1) {
300 NewSubIdx = ARM::qqsub_0;
303 } else if (SubIndices[0] == ARM::qsub_2) {
304 // 2 Q registers -> 1 QQ register (2nd).
305 if (Size == 512 && SubIndices[1] == ARM::qsub_3) {
306 NewSubIdx = ARM::qqsub_1;
309 } else if (SubIndices[0] == ARM::dsub_0) {
310 // 2 D registers -> 1 Q register.
311 if (Size >= 128 && SubIndices[1] == ARM::dsub_1) {
313 NewSubIdx = ARM::qsub_0;
316 } else if (SubIndices[0] == ARM::dsub_2) {
317 // 2 D registers -> 1 Q register (2nd).
318 if (Size >= 256 && SubIndices[1] == ARM::dsub_3) {
319 NewSubIdx = ARM::qsub_1;
322 } else if (SubIndices[0] == ARM::dsub_4) {
323 // 2 D registers -> 1 Q register (3rd).
324 if (Size == 512 && SubIndices[1] == ARM::dsub_5) {
325 NewSubIdx = ARM::qsub_2;
328 } else if (SubIndices[0] == ARM::dsub_6) {
329 // 2 D registers -> 1 Q register (3rd).
330 if (Size == 512 && SubIndices[1] == ARM::dsub_7) {
331 NewSubIdx = ARM::qsub_3;
334 } else if (SubIndices[0] == ARM::ssub_0) {
335 // 2 S registers -> 1 D register.
336 if (SubIndices[1] == ARM::ssub_1) {
338 NewSubIdx = ARM::dsub_0;
341 } else if (SubIndices[0] == ARM::ssub_2) {
342 // 2 S registers -> 1 D register (2nd).
343 if (Size >= 128 && SubIndices[1] == ARM::ssub_3) {
344 NewSubIdx = ARM::dsub_1;
352 const TargetRegisterClass*
353 ARMBaseRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC)
355 const TargetRegisterClass *Super = RC;
356 TargetRegisterClass::sc_iterator I = RC->superclasses_begin();
358 switch (Super->getID()) {
359 case ARM::GPRRegClassID:
360 case ARM::SPRRegClassID:
361 case ARM::DPRRegClassID:
362 case ARM::QPRRegClassID:
363 case ARM::QQPRRegClassID:
364 case ARM::QQQQPRRegClassID:
372 const TargetRegisterClass *
373 ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
374 return ARM::GPRRegisterClass;
377 const TargetRegisterClass *
378 ARMBaseRegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
379 if (RC == &ARM::CCRRegClass)
380 return 0; // Can't copy CCR registers.
385 ARMBaseRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
386 MachineFunction &MF) const {
387 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
389 switch (RC->getID()) {
392 case ARM::tGPRRegClassID:
393 return TFI->hasFP(MF) ? 4 : 5;
394 case ARM::GPRRegClassID: {
395 unsigned FP = TFI->hasFP(MF) ? 1 : 0;
396 return 10 - FP - (STI.isR9Reserved() ? 1 : 0);
398 case ARM::SPRRegClassID: // Currently not used as 'rep' register class.
399 case ARM::DPRRegClassID:
404 /// getRawAllocationOrder - Returns the register allocation order for a
405 /// specified register class with a target-dependent hint.
407 ARMBaseRegisterInfo::getRawAllocationOrder(const TargetRegisterClass *RC,
408 unsigned HintType, unsigned HintReg,
409 const MachineFunction &MF) const {
410 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
411 // Alternative register allocation orders when favoring even / odd registers
412 // of register pairs.
414 // No FP, R9 is available.
415 static const unsigned GPREven1[] = {
416 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
417 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
420 static const unsigned GPROdd1[] = {
421 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
422 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
426 // FP is R7, R9 is available.
427 static const unsigned GPREven2[] = {
428 ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
429 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
432 static const unsigned GPROdd2[] = {
433 ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
434 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
438 // FP is R11, R9 is available.
439 static const unsigned GPREven3[] = {
440 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
441 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
444 static const unsigned GPROdd3[] = {
445 ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
446 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
450 // No FP, R9 is not available.
451 static const unsigned GPREven4[] = {
452 ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
453 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
456 static const unsigned GPROdd4[] = {
457 ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
458 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
462 // FP is R7, R9 is not available.
463 static const unsigned GPREven5[] = {
464 ARM::R0, ARM::R2, ARM::R4, ARM::R10,
465 ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
468 static const unsigned GPROdd5[] = {
469 ARM::R1, ARM::R3, ARM::R5, ARM::R11,
470 ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
474 // FP is R11, R9 is not available.
475 static const unsigned GPREven6[] = {
476 ARM::R0, ARM::R2, ARM::R4, ARM::R6,
477 ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
479 static const unsigned GPROdd6[] = {
480 ARM::R1, ARM::R3, ARM::R5, ARM::R7,
481 ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
484 // We only support even/odd hints for GPR and rGPR.
485 if (RC != ARM::GPRRegisterClass && RC != ARM::rGPRRegisterClass)
486 return RC->getRawAllocationOrder(MF);
488 if (HintType == ARMRI::RegPairEven) {
489 if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
490 // It's no longer possible to fulfill this hint. Return the default
492 return RC->getRawAllocationOrder(MF);
494 if (!TFI->hasFP(MF)) {
495 if (!STI.isR9Reserved())
496 return makeArrayRef(GPREven1);
498 return makeArrayRef(GPREven4);
499 } else if (FramePtr == ARM::R7) {
500 if (!STI.isR9Reserved())
501 return makeArrayRef(GPREven2);
503 return makeArrayRef(GPREven5);
504 } else { // FramePtr == ARM::R11
505 if (!STI.isR9Reserved())
506 return makeArrayRef(GPREven3);
508 return makeArrayRef(GPREven6);
510 } else if (HintType == ARMRI::RegPairOdd) {
511 if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
512 // It's no longer possible to fulfill this hint. Return the default
514 return RC->getRawAllocationOrder(MF);
516 if (!TFI->hasFP(MF)) {
517 if (!STI.isR9Reserved())
518 return makeArrayRef(GPROdd1);
520 return makeArrayRef(GPROdd4);
521 } else if (FramePtr == ARM::R7) {
522 if (!STI.isR9Reserved())
523 return makeArrayRef(GPROdd2);
525 return makeArrayRef(GPROdd5);
526 } else { // FramePtr == ARM::R11
527 if (!STI.isR9Reserved())
528 return makeArrayRef(GPROdd3);
530 return makeArrayRef(GPROdd6);
533 return RC->getRawAllocationOrder(MF);
536 /// ResolveRegAllocHint - Resolves the specified register allocation hint
537 /// to a physical register. Returns the physical register if it is successful.
539 ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
540 const MachineFunction &MF) const {
541 if (Reg == 0 || !isPhysicalRegister(Reg))
545 else if (Type == (unsigned)ARMRI::RegPairOdd)
547 return getRegisterPairOdd(Reg, MF);
548 else if (Type == (unsigned)ARMRI::RegPairEven)
550 return getRegisterPairEven(Reg, MF);
555 ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
556 MachineFunction &MF) const {
557 MachineRegisterInfo *MRI = &MF.getRegInfo();
558 std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
559 if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
560 Hint.first == (unsigned)ARMRI::RegPairEven) &&
561 TargetRegisterInfo::isVirtualRegister(Hint.second)) {
562 // If 'Reg' is one of the even / odd register pair and it's now changed
563 // (e.g. coalesced) into a different register. The other register of the
564 // pair allocation hint must be updated to reflect the relationship
566 unsigned OtherReg = Hint.second;
567 Hint = MRI->getRegAllocationHint(OtherReg);
568 if (Hint.second == Reg)
569 // Make sure the pair has not already divorced.
570 MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
575 ARMBaseRegisterInfo::avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
576 // CortexA9 has a Write-after-write hazard for NEON registers.
577 if (!STI.isCortexA9())
580 switch (RC->getID()) {
581 case ARM::DPRRegClassID:
582 case ARM::DPR_8RegClassID:
583 case ARM::DPR_VFP2RegClassID:
584 case ARM::QPRRegClassID:
585 case ARM::QPR_8RegClassID:
586 case ARM::QPR_VFP2RegClassID:
587 case ARM::SPRRegClassID:
588 case ARM::SPR_8RegClassID:
589 // Avoid reusing S, D, and Q registers.
590 // Don't increase register pressure for QQ and QQQQ.
597 bool ARMBaseRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
598 const MachineFrameInfo *MFI = MF.getFrameInfo();
599 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
601 if (!EnableBasePointer)
604 if (needsStackRealignment(MF) && MFI->hasVarSizedObjects())
607 // Thumb has trouble with negative offsets from the FP. Thumb2 has a limited
608 // negative range for ldr/str (255), and thumb1 is positive offsets only.
609 // It's going to be better to use the SP or Base Pointer instead. When there
610 // are variable sized objects, we can't reference off of the SP, so we
611 // reserve a Base Pointer.
612 if (AFI->isThumbFunction() && MFI->hasVarSizedObjects()) {
613 // Conservatively estimate whether the negative offset from the frame
614 // pointer will be sufficient to reach. If a function has a smallish
615 // frame, it's less likely to have lots of spills and callee saved
616 // space, so it's all more likely to be within range of the frame pointer.
617 // If it's wrong, the scavenger will still enable access to work, it just
619 if (AFI->isThumb2Function() && MFI->getLocalFrameSize() < 128)
627 bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
628 const MachineFrameInfo *MFI = MF.getFrameInfo();
629 const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
630 // We can't realign the stack if:
631 // 1. Dynamic stack realignment is explicitly disabled,
632 // 2. This is a Thumb1 function (it's not useful, so we don't bother), or
633 // 3. There are VLAs in the function and the base pointer is disabled.
634 return (RealignStack && !AFI->isThumb1OnlyFunction() &&
635 (!MFI->hasVarSizedObjects() || EnableBasePointer));
638 bool ARMBaseRegisterInfo::
639 needsStackRealignment(const MachineFunction &MF) const {
640 const MachineFrameInfo *MFI = MF.getFrameInfo();
641 const Function *F = MF.getFunction();
642 unsigned StackAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
643 bool requiresRealignment = ((MFI->getLocalFrameMaxAlign() > StackAlign) ||
644 F->hasFnAttr(Attribute::StackAlignment));
646 return requiresRealignment && canRealignStack(MF);
649 bool ARMBaseRegisterInfo::
650 cannotEliminateFrame(const MachineFunction &MF) const {
651 const MachineFrameInfo *MFI = MF.getFrameInfo();
652 if (DisableFramePointerElim(MF) && MFI->adjustsStack())
654 return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
655 || needsStackRealignment(MF);
659 ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
660 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
667 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
668 llvm_unreachable("What is the exception register");
672 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
673 llvm_unreachable("What is the exception handler register");
677 unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
678 const MachineFunction &MF) const {
681 // Return 0 if either register of the pair is a special register.
690 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
693 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
695 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
767 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
768 const MachineFunction &MF) const {
771 // Return 0 if either register of the pair is a special register.
780 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
783 return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
785 return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
857 /// emitLoadConstPool - Emits a load from constpool to materialize the
858 /// specified immediate.
859 void ARMBaseRegisterInfo::
860 emitLoadConstPool(MachineBasicBlock &MBB,
861 MachineBasicBlock::iterator &MBBI,
863 unsigned DestReg, unsigned SubIdx, int Val,
864 ARMCC::CondCodes Pred,
865 unsigned PredReg, unsigned MIFlags) const {
866 MachineFunction &MF = *MBB.getParent();
867 MachineConstantPool *ConstantPool = MF.getConstantPool();
869 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
870 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
872 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
873 .addReg(DestReg, getDefRegState(true), SubIdx)
874 .addConstantPoolIndex(Idx)
875 .addImm(0).addImm(Pred).addReg(PredReg)
876 .setMIFlags(MIFlags);
879 bool ARMBaseRegisterInfo::
880 requiresRegisterScavenging(const MachineFunction &MF) const {
884 bool ARMBaseRegisterInfo::
885 requiresFrameIndexScavenging(const MachineFunction &MF) const {
889 bool ARMBaseRegisterInfo::
890 requiresVirtualBaseRegisters(const MachineFunction &MF) const {
891 return EnableLocalStackAlloc;
895 emitSPUpdate(bool isARM,
896 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
897 DebugLoc dl, const ARMBaseInstrInfo &TII,
899 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
901 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
904 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
909 void ARMBaseRegisterInfo::
910 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
911 MachineBasicBlock::iterator I) const {
912 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
913 if (!TFI->hasReservedCallFrame(MF)) {
914 // If we have alloca, convert as follows:
915 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
916 // ADJCALLSTACKUP -> add, sp, sp, amount
917 MachineInstr *Old = I;
918 DebugLoc dl = Old->getDebugLoc();
919 unsigned Amount = Old->getOperand(0).getImm();
921 // We need to keep the stack aligned properly. To do this, we round the
922 // amount of space needed for the outgoing arguments up to the next
923 // alignment boundary.
924 unsigned Align = TFI->getStackAlignment();
925 Amount = (Amount+Align-1)/Align*Align;
927 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
928 assert(!AFI->isThumb1OnlyFunction() &&
929 "This eliminateCallFramePseudoInstr does not support Thumb1!");
930 bool isARM = !AFI->isThumbFunction();
932 // Replace the pseudo instruction with a new instruction...
933 unsigned Opc = Old->getOpcode();
934 int PIdx = Old->findFirstPredOperandIdx();
935 ARMCC::CondCodes Pred = (PIdx == -1)
936 ? ARMCC::AL : (ARMCC::CondCodes)Old->getOperand(PIdx).getImm();
937 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
938 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
939 unsigned PredReg = Old->getOperand(2).getReg();
940 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
942 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
943 unsigned PredReg = Old->getOperand(3).getReg();
944 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
945 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
952 int64_t ARMBaseRegisterInfo::
953 getFrameIndexInstrOffset(const MachineInstr *MI, int Idx) const {
954 const MCInstrDesc &Desc = MI->getDesc();
955 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
956 int64_t InstrOffs = 0;;
960 case ARMII::AddrModeT2_i8:
961 case ARMII::AddrModeT2_i12:
962 case ARMII::AddrMode_i12:
963 InstrOffs = MI->getOperand(Idx+1).getImm();
966 case ARMII::AddrMode5: {
968 const MachineOperand &OffOp = MI->getOperand(Idx+1);
969 InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
970 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
971 InstrOffs = -InstrOffs;
975 case ARMII::AddrMode2: {
977 InstrOffs = ARM_AM::getAM2Offset(MI->getOperand(ImmIdx).getImm());
978 if (ARM_AM::getAM2Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
979 InstrOffs = -InstrOffs;
982 case ARMII::AddrMode3: {
984 InstrOffs = ARM_AM::getAM3Offset(MI->getOperand(ImmIdx).getImm());
985 if (ARM_AM::getAM3Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
986 InstrOffs = -InstrOffs;
989 case ARMII::AddrModeT1_s: {
991 InstrOffs = MI->getOperand(ImmIdx).getImm();
996 llvm_unreachable("Unsupported addressing mode!");
1000 return InstrOffs * Scale;
1003 /// needsFrameBaseReg - Returns true if the instruction's frame index
1004 /// reference would be better served by a base register other than FP
1005 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
1006 /// references it should create new base registers for.
1007 bool ARMBaseRegisterInfo::
1008 needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
1009 for (unsigned i = 0; !MI->getOperand(i).isFI(); ++i) {
1010 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
1013 // It's the load/store FI references that cause issues, as it can be difficult
1014 // to materialize the offset if it won't fit in the literal field. Estimate
1015 // based on the size of the local frame and some conservative assumptions
1016 // about the rest of the stack frame (note, this is pre-regalloc, so
1017 // we don't know everything for certain yet) whether this offset is likely
1018 // to be out of range of the immediate. Return true if so.
1020 // We only generate virtual base registers for loads and stores, so
1021 // return false for everything else.
1022 unsigned Opc = MI->getOpcode();
1024 case ARM::LDRi12: case ARM::LDRH: case ARM::LDRBi12:
1025 case ARM::STRi12: case ARM::STRH: case ARM::STRBi12:
1026 case ARM::t2LDRi12: case ARM::t2LDRi8:
1027 case ARM::t2STRi12: case ARM::t2STRi8:
1028 case ARM::VLDRS: case ARM::VLDRD:
1029 case ARM::VSTRS: case ARM::VSTRD:
1030 case ARM::tSTRspi: case ARM::tLDRspi:
1031 if (ForceAllBaseRegAlloc)
1038 // Without a virtual base register, if the function has variable sized
1039 // objects, all fixed-size local references will be via the frame pointer,
1040 // Approximate the offset and see if it's legal for the instruction.
1041 // Note that the incoming offset is based on the SP value at function entry,
1042 // so it'll be negative.
1043 MachineFunction &MF = *MI->getParent()->getParent();
1044 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
1045 MachineFrameInfo *MFI = MF.getFrameInfo();
1046 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1048 // Estimate an offset from the frame pointer.
1049 // Conservatively assume all callee-saved registers get pushed. R4-R6
1050 // will be earlier than the FP, so we ignore those.
1052 int64_t FPOffset = Offset - 8;
1053 // ARM and Thumb2 functions also need to consider R8-R11 and D8-D15
1054 if (!AFI->isThumbFunction() || !AFI->isThumb1OnlyFunction())
1056 // Estimate an offset from the stack pointer.
1057 // The incoming offset is relating to the SP at the start of the function,
1058 // but when we access the local it'll be relative to the SP after local
1059 // allocation, so adjust our SP-relative offset by that allocation size.
1061 Offset += MFI->getLocalFrameSize();
1062 // Assume that we'll have at least some spill slots allocated.
1063 // FIXME: This is a total SWAG number. We should run some statistics
1064 // and pick a real one.
1065 Offset += 128; // 128 bytes of spill slots
1067 // If there is a frame pointer, try using it.
1068 // The FP is only available if there is no dynamic realignment. We
1069 // don't know for sure yet whether we'll need that, so we guess based
1070 // on whether there are any local variables that would trigger it.
1071 unsigned StackAlign = TFI->getStackAlignment();
1072 if (TFI->hasFP(MF) &&
1073 !((MFI->getLocalFrameMaxAlign() > StackAlign) && canRealignStack(MF))) {
1074 if (isFrameOffsetLegal(MI, FPOffset))
1077 // If we can reference via the stack pointer, try that.
1078 // FIXME: This (and the code that resolves the references) can be improved
1079 // to only disallow SP relative references in the live range of
1080 // the VLA(s). In practice, it's unclear how much difference that
1081 // would make, but it may be worth doing.
1082 if (!MFI->hasVarSizedObjects() && isFrameOffsetLegal(MI, Offset))
1085 // The offset likely isn't legal, we want to allocate a virtual base register.
1089 /// materializeFrameBaseRegister - Insert defining instruction(s) for BaseReg to
1090 /// be a pointer to FrameIdx at the beginning of the basic block.
1091 void ARMBaseRegisterInfo::
1092 materializeFrameBaseRegister(MachineBasicBlock *MBB,
1093 unsigned BaseReg, int FrameIdx,
1094 int64_t Offset) const {
1095 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
1096 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri :
1097 (AFI->isThumb1OnlyFunction() ? ARM::tADDrSPi : ARM::t2ADDri);
1099 MachineBasicBlock::iterator Ins = MBB->begin();
1100 DebugLoc DL; // Defaults to "unknown"
1101 if (Ins != MBB->end())
1102 DL = Ins->getDebugLoc();
1104 const MCInstrDesc &MCID = TII.get(ADDriOpc);
1105 MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
1106 MRI.constrainRegClass(BaseReg, TII.getRegClass(MCID, 0, this));
1108 MachineInstrBuilder MIB = AddDefaultPred(BuildMI(*MBB, Ins, DL, MCID, BaseReg)
1109 .addFrameIndex(FrameIdx).addImm(Offset));
1111 if (!AFI->isThumb1OnlyFunction())
1116 ARMBaseRegisterInfo::resolveFrameIndex(MachineBasicBlock::iterator I,
1117 unsigned BaseReg, int64_t Offset) const {
1118 MachineInstr &MI = *I;
1119 MachineBasicBlock &MBB = *MI.getParent();
1120 MachineFunction &MF = *MBB.getParent();
1121 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1122 int Off = Offset; // ARM doesn't need the general 64-bit offsets
1125 assert(!AFI->isThumb1OnlyFunction() &&
1126 "This resolveFrameIndex does not support Thumb1!");
1128 while (!MI.getOperand(i).isFI()) {
1130 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1133 if (!AFI->isThumbFunction())
1134 Done = rewriteARMFrameIndex(MI, i, BaseReg, Off, TII);
1136 assert(AFI->isThumb2Function());
1137 Done = rewriteT2FrameIndex(MI, i, BaseReg, Off, TII);
1139 assert (Done && "Unable to resolve frame index!");
1143 bool ARMBaseRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
1144 int64_t Offset) const {
1145 const MCInstrDesc &Desc = MI->getDesc();
1146 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
1149 while (!MI->getOperand(i).isFI()) {
1151 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
1154 // AddrMode4 and AddrMode6 cannot handle any offset.
1155 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
1158 unsigned NumBits = 0;
1160 bool isSigned = true;
1162 case ARMII::AddrModeT2_i8:
1163 case ARMII::AddrModeT2_i12:
1164 // i8 supports only negative, and i12 supports only positive, so
1165 // based on Offset sign, consider the appropriate instruction
1174 case ARMII::AddrMode5:
1175 // VFP address mode.
1179 case ARMII::AddrMode_i12:
1180 case ARMII::AddrMode2:
1183 case ARMII::AddrMode3:
1186 case ARMII::AddrModeT1_s:
1192 llvm_unreachable("Unsupported addressing mode!");
1196 Offset += getFrameIndexInstrOffset(MI, i);
1197 // Make sure the offset is encodable for instructions that scale the
1199 if ((Offset & (Scale-1)) != 0)
1202 if (isSigned && Offset < 0)
1205 unsigned Mask = (1 << NumBits) - 1;
1206 if ((unsigned)Offset <= Mask * Scale)
1213 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1214 int SPAdj, RegScavenger *RS) const {
1216 MachineInstr &MI = *II;
1217 MachineBasicBlock &MBB = *MI.getParent();
1218 MachineFunction &MF = *MBB.getParent();
1219 const ARMFrameLowering *TFI =
1220 static_cast<const ARMFrameLowering*>(MF.getTarget().getFrameLowering());
1221 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1222 assert(!AFI->isThumb1OnlyFunction() &&
1223 "This eliminateFrameIndex does not support Thumb1!");
1225 while (!MI.getOperand(i).isFI()) {
1227 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1230 int FrameIndex = MI.getOperand(i).getIndex();
1233 int Offset = TFI->ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
1235 // Special handling of dbg_value instructions.
1236 if (MI.isDebugValue()) {
1237 MI.getOperand(i). ChangeToRegister(FrameReg, false /*isDef*/);
1238 MI.getOperand(i+1).ChangeToImmediate(Offset);
1242 // Modify MI as necessary to handle as much of 'Offset' as possible
1244 if (!AFI->isThumbFunction())
1245 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1247 assert(AFI->isThumb2Function());
1248 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1253 // If we get here, the immediate doesn't fit into the instruction. We folded
1254 // as much as possible above, handle the rest, providing a register that is
1257 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1258 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1259 "This code isn't needed if offset already handled!");
1261 unsigned ScratchReg = 0;
1262 int PIdx = MI.findFirstPredOperandIdx();
1263 ARMCC::CondCodes Pred = (PIdx == -1)
1264 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1265 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1267 // Must be addrmode4/6.
1268 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1270 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1271 if (!AFI->isThumbFunction())
1272 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1273 Offset, Pred, PredReg, TII);
1275 assert(AFI->isThumb2Function());
1276 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1277 Offset, Pred, PredReg, TII);
1279 // Update the original instruction to use the scratch register.
1280 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);