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.
683 case ARM::R1: return ARM::R0;
684 case ARM::R3: return ARM::R2;
685 case ARM::R5: return ARM::R4;
687 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
689 case ARM::R9: return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
690 case ARM::R11: return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
692 case ARM::S1: return ARM::S0;
693 case ARM::S3: return ARM::S2;
694 case ARM::S5: return ARM::S4;
695 case ARM::S7: return ARM::S6;
696 case ARM::S9: return ARM::S8;
697 case ARM::S11: return ARM::S10;
698 case ARM::S13: return ARM::S12;
699 case ARM::S15: return ARM::S14;
700 case ARM::S17: return ARM::S16;
701 case ARM::S19: return ARM::S18;
702 case ARM::S21: return ARM::S20;
703 case ARM::S23: return ARM::S22;
704 case ARM::S25: return ARM::S24;
705 case ARM::S27: return ARM::S26;
706 case ARM::S29: return ARM::S28;
707 case ARM::S31: return ARM::S30;
709 case ARM::D1: return ARM::D0;
710 case ARM::D3: return ARM::D2;
711 case ARM::D5: return ARM::D4;
712 case ARM::D7: return ARM::D6;
713 case ARM::D9: return ARM::D8;
714 case ARM::D11: return ARM::D10;
715 case ARM::D13: return ARM::D12;
716 case ARM::D15: return ARM::D14;
717 case ARM::D17: return ARM::D16;
718 case ARM::D19: return ARM::D18;
719 case ARM::D21: return ARM::D20;
720 case ARM::D23: return ARM::D22;
721 case ARM::D25: return ARM::D24;
722 case ARM::D27: return ARM::D26;
723 case ARM::D29: return ARM::D28;
724 case ARM::D31: return ARM::D30;
730 unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
731 const MachineFunction &MF) const {
734 // Return 0 if either register of the pair is a special register.
736 case ARM::R0: return ARM::R1;
737 case ARM::R2: return ARM::R3;
738 case ARM::R4: return ARM::R5;
740 return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
742 case ARM::R8: return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
743 case ARM::R10: return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
745 case ARM::S0: return ARM::S1;
746 case ARM::S2: return ARM::S3;
747 case ARM::S4: return ARM::S5;
748 case ARM::S6: return ARM::S7;
749 case ARM::S8: return ARM::S9;
750 case ARM::S10: return ARM::S11;
751 case ARM::S12: return ARM::S13;
752 case ARM::S14: return ARM::S15;
753 case ARM::S16: return ARM::S17;
754 case ARM::S18: return ARM::S19;
755 case ARM::S20: return ARM::S21;
756 case ARM::S22: return ARM::S23;
757 case ARM::S24: return ARM::S25;
758 case ARM::S26: return ARM::S27;
759 case ARM::S28: return ARM::S29;
760 case ARM::S30: return ARM::S31;
762 case ARM::D0: return ARM::D1;
763 case ARM::D2: return ARM::D3;
764 case ARM::D4: return ARM::D5;
765 case ARM::D6: return ARM::D7;
766 case ARM::D8: return ARM::D9;
767 case ARM::D10: return ARM::D11;
768 case ARM::D12: return ARM::D13;
769 case ARM::D14: return ARM::D15;
770 case ARM::D16: return ARM::D17;
771 case ARM::D18: return ARM::D19;
772 case ARM::D20: return ARM::D21;
773 case ARM::D22: return ARM::D23;
774 case ARM::D24: return ARM::D25;
775 case ARM::D26: return ARM::D27;
776 case ARM::D28: return ARM::D29;
777 case ARM::D30: return ARM::D31;
783 /// emitLoadConstPool - Emits a load from constpool to materialize the
784 /// specified immediate.
785 void ARMBaseRegisterInfo::
786 emitLoadConstPool(MachineBasicBlock &MBB,
787 MachineBasicBlock::iterator &MBBI,
789 unsigned DestReg, unsigned SubIdx, int Val,
790 ARMCC::CondCodes Pred,
791 unsigned PredReg, unsigned MIFlags) const {
792 MachineFunction &MF = *MBB.getParent();
793 MachineConstantPool *ConstantPool = MF.getConstantPool();
795 ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
796 unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
798 BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
799 .addReg(DestReg, getDefRegState(true), SubIdx)
800 .addConstantPoolIndex(Idx)
801 .addImm(0).addImm(Pred).addReg(PredReg)
802 .setMIFlags(MIFlags);
805 bool ARMBaseRegisterInfo::
806 requiresRegisterScavenging(const MachineFunction &MF) const {
810 bool ARMBaseRegisterInfo::
811 requiresFrameIndexScavenging(const MachineFunction &MF) const {
815 bool ARMBaseRegisterInfo::
816 requiresVirtualBaseRegisters(const MachineFunction &MF) const {
817 return EnableLocalStackAlloc;
821 emitSPUpdate(bool isARM,
822 MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
823 DebugLoc dl, const ARMBaseInstrInfo &TII,
825 ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
827 emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
830 emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
835 void ARMBaseRegisterInfo::
836 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
837 MachineBasicBlock::iterator I) const {
838 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
839 if (!TFI->hasReservedCallFrame(MF)) {
840 // If we have alloca, convert as follows:
841 // ADJCALLSTACKDOWN -> sub, sp, sp, amount
842 // ADJCALLSTACKUP -> add, sp, sp, amount
843 MachineInstr *Old = I;
844 DebugLoc dl = Old->getDebugLoc();
845 unsigned Amount = Old->getOperand(0).getImm();
847 // We need to keep the stack aligned properly. To do this, we round the
848 // amount of space needed for the outgoing arguments up to the next
849 // alignment boundary.
850 unsigned Align = TFI->getStackAlignment();
851 Amount = (Amount+Align-1)/Align*Align;
853 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
854 assert(!AFI->isThumb1OnlyFunction() &&
855 "This eliminateCallFramePseudoInstr does not support Thumb1!");
856 bool isARM = !AFI->isThumbFunction();
858 // Replace the pseudo instruction with a new instruction...
859 unsigned Opc = Old->getOpcode();
860 int PIdx = Old->findFirstPredOperandIdx();
861 ARMCC::CondCodes Pred = (PIdx == -1)
862 ? ARMCC::AL : (ARMCC::CondCodes)Old->getOperand(PIdx).getImm();
863 if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
864 // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
865 unsigned PredReg = Old->getOperand(2).getReg();
866 emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
868 // Note: PredReg is operand 3 for ADJCALLSTACKUP.
869 unsigned PredReg = Old->getOperand(3).getReg();
870 assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
871 emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
878 int64_t ARMBaseRegisterInfo::
879 getFrameIndexInstrOffset(const MachineInstr *MI, int Idx) const {
880 const MCInstrDesc &Desc = MI->getDesc();
881 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
882 int64_t InstrOffs = 0;;
886 case ARMII::AddrModeT2_i8:
887 case ARMII::AddrModeT2_i12:
888 case ARMII::AddrMode_i12:
889 InstrOffs = MI->getOperand(Idx+1).getImm();
892 case ARMII::AddrMode5: {
894 const MachineOperand &OffOp = MI->getOperand(Idx+1);
895 InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
896 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
897 InstrOffs = -InstrOffs;
901 case ARMII::AddrMode2: {
903 InstrOffs = ARM_AM::getAM2Offset(MI->getOperand(ImmIdx).getImm());
904 if (ARM_AM::getAM2Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
905 InstrOffs = -InstrOffs;
908 case ARMII::AddrMode3: {
910 InstrOffs = ARM_AM::getAM3Offset(MI->getOperand(ImmIdx).getImm());
911 if (ARM_AM::getAM3Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
912 InstrOffs = -InstrOffs;
915 case ARMII::AddrModeT1_s: {
917 InstrOffs = MI->getOperand(ImmIdx).getImm();
922 llvm_unreachable("Unsupported addressing mode!");
926 return InstrOffs * Scale;
929 /// needsFrameBaseReg - Returns true if the instruction's frame index
930 /// reference would be better served by a base register other than FP
931 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
932 /// references it should create new base registers for.
933 bool ARMBaseRegisterInfo::
934 needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
935 for (unsigned i = 0; !MI->getOperand(i).isFI(); ++i) {
936 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
939 // It's the load/store FI references that cause issues, as it can be difficult
940 // to materialize the offset if it won't fit in the literal field. Estimate
941 // based on the size of the local frame and some conservative assumptions
942 // about the rest of the stack frame (note, this is pre-regalloc, so
943 // we don't know everything for certain yet) whether this offset is likely
944 // to be out of range of the immediate. Return true if so.
946 // We only generate virtual base registers for loads and stores, so
947 // return false for everything else.
948 unsigned Opc = MI->getOpcode();
950 case ARM::LDRi12: case ARM::LDRH: case ARM::LDRBi12:
951 case ARM::STRi12: case ARM::STRH: case ARM::STRBi12:
952 case ARM::t2LDRi12: case ARM::t2LDRi8:
953 case ARM::t2STRi12: case ARM::t2STRi8:
954 case ARM::VLDRS: case ARM::VLDRD:
955 case ARM::VSTRS: case ARM::VSTRD:
956 case ARM::tSTRspi: case ARM::tLDRspi:
957 if (ForceAllBaseRegAlloc)
964 // Without a virtual base register, if the function has variable sized
965 // objects, all fixed-size local references will be via the frame pointer,
966 // Approximate the offset and see if it's legal for the instruction.
967 // Note that the incoming offset is based on the SP value at function entry,
968 // so it'll be negative.
969 MachineFunction &MF = *MI->getParent()->getParent();
970 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
971 MachineFrameInfo *MFI = MF.getFrameInfo();
972 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
974 // Estimate an offset from the frame pointer.
975 // Conservatively assume all callee-saved registers get pushed. R4-R6
976 // will be earlier than the FP, so we ignore those.
978 int64_t FPOffset = Offset - 8;
979 // ARM and Thumb2 functions also need to consider R8-R11 and D8-D15
980 if (!AFI->isThumbFunction() || !AFI->isThumb1OnlyFunction())
982 // Estimate an offset from the stack pointer.
983 // The incoming offset is relating to the SP at the start of the function,
984 // but when we access the local it'll be relative to the SP after local
985 // allocation, so adjust our SP-relative offset by that allocation size.
987 Offset += MFI->getLocalFrameSize();
988 // Assume that we'll have at least some spill slots allocated.
989 // FIXME: This is a total SWAG number. We should run some statistics
990 // and pick a real one.
991 Offset += 128; // 128 bytes of spill slots
993 // If there is a frame pointer, try using it.
994 // The FP is only available if there is no dynamic realignment. We
995 // don't know for sure yet whether we'll need that, so we guess based
996 // on whether there are any local variables that would trigger it.
997 unsigned StackAlign = TFI->getStackAlignment();
998 if (TFI->hasFP(MF) &&
999 !((MFI->getLocalFrameMaxAlign() > StackAlign) && canRealignStack(MF))) {
1000 if (isFrameOffsetLegal(MI, FPOffset))
1003 // If we can reference via the stack pointer, try that.
1004 // FIXME: This (and the code that resolves the references) can be improved
1005 // to only disallow SP relative references in the live range of
1006 // the VLA(s). In practice, it's unclear how much difference that
1007 // would make, but it may be worth doing.
1008 if (!MFI->hasVarSizedObjects() && isFrameOffsetLegal(MI, Offset))
1011 // The offset likely isn't legal, we want to allocate a virtual base register.
1015 /// materializeFrameBaseRegister - Insert defining instruction(s) for BaseReg to
1016 /// be a pointer to FrameIdx at the beginning of the basic block.
1017 void ARMBaseRegisterInfo::
1018 materializeFrameBaseRegister(MachineBasicBlock *MBB,
1019 unsigned BaseReg, int FrameIdx,
1020 int64_t Offset) const {
1021 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
1022 unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri :
1023 (AFI->isThumb1OnlyFunction() ? ARM::tADDrSPi : ARM::t2ADDri);
1025 MachineBasicBlock::iterator Ins = MBB->begin();
1026 DebugLoc DL; // Defaults to "unknown"
1027 if (Ins != MBB->end())
1028 DL = Ins->getDebugLoc();
1030 const MCInstrDesc &MCID = TII.get(ADDriOpc);
1031 MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
1032 MRI.constrainRegClass(BaseReg, TII.getRegClass(MCID, 0, this));
1034 MachineInstrBuilder MIB = AddDefaultPred(BuildMI(*MBB, Ins, DL, MCID, BaseReg)
1035 .addFrameIndex(FrameIdx).addImm(Offset));
1037 if (!AFI->isThumb1OnlyFunction())
1042 ARMBaseRegisterInfo::resolveFrameIndex(MachineBasicBlock::iterator I,
1043 unsigned BaseReg, int64_t Offset) const {
1044 MachineInstr &MI = *I;
1045 MachineBasicBlock &MBB = *MI.getParent();
1046 MachineFunction &MF = *MBB.getParent();
1047 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1048 int Off = Offset; // ARM doesn't need the general 64-bit offsets
1051 assert(!AFI->isThumb1OnlyFunction() &&
1052 "This resolveFrameIndex does not support Thumb1!");
1054 while (!MI.getOperand(i).isFI()) {
1056 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1059 if (!AFI->isThumbFunction())
1060 Done = rewriteARMFrameIndex(MI, i, BaseReg, Off, TII);
1062 assert(AFI->isThumb2Function());
1063 Done = rewriteT2FrameIndex(MI, i, BaseReg, Off, TII);
1065 assert (Done && "Unable to resolve frame index!");
1069 bool ARMBaseRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
1070 int64_t Offset) const {
1071 const MCInstrDesc &Desc = MI->getDesc();
1072 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
1075 while (!MI->getOperand(i).isFI()) {
1077 assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
1080 // AddrMode4 and AddrMode6 cannot handle any offset.
1081 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
1084 unsigned NumBits = 0;
1086 bool isSigned = true;
1088 case ARMII::AddrModeT2_i8:
1089 case ARMII::AddrModeT2_i12:
1090 // i8 supports only negative, and i12 supports only positive, so
1091 // based on Offset sign, consider the appropriate instruction
1100 case ARMII::AddrMode5:
1101 // VFP address mode.
1105 case ARMII::AddrMode_i12:
1106 case ARMII::AddrMode2:
1109 case ARMII::AddrMode3:
1112 case ARMII::AddrModeT1_s:
1118 llvm_unreachable("Unsupported addressing mode!");
1122 Offset += getFrameIndexInstrOffset(MI, i);
1123 // Make sure the offset is encodable for instructions that scale the
1125 if ((Offset & (Scale-1)) != 0)
1128 if (isSigned && Offset < 0)
1131 unsigned Mask = (1 << NumBits) - 1;
1132 if ((unsigned)Offset <= Mask * Scale)
1139 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1140 int SPAdj, RegScavenger *RS) const {
1142 MachineInstr &MI = *II;
1143 MachineBasicBlock &MBB = *MI.getParent();
1144 MachineFunction &MF = *MBB.getParent();
1145 const ARMFrameLowering *TFI =
1146 static_cast<const ARMFrameLowering*>(MF.getTarget().getFrameLowering());
1147 ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1148 assert(!AFI->isThumb1OnlyFunction() &&
1149 "This eliminateFrameIndex does not support Thumb1!");
1151 while (!MI.getOperand(i).isFI()) {
1153 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1156 int FrameIndex = MI.getOperand(i).getIndex();
1159 int Offset = TFI->ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
1161 // Special handling of dbg_value instructions.
1162 if (MI.isDebugValue()) {
1163 MI.getOperand(i). ChangeToRegister(FrameReg, false /*isDef*/);
1164 MI.getOperand(i+1).ChangeToImmediate(Offset);
1168 // Modify MI as necessary to handle as much of 'Offset' as possible
1170 if (!AFI->isThumbFunction())
1171 Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1173 assert(AFI->isThumb2Function());
1174 Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1179 // If we get here, the immediate doesn't fit into the instruction. We folded
1180 // as much as possible above, handle the rest, providing a register that is
1183 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1184 (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1185 "This code isn't needed if offset already handled!");
1187 unsigned ScratchReg = 0;
1188 int PIdx = MI.findFirstPredOperandIdx();
1189 ARMCC::CondCodes Pred = (PIdx == -1)
1190 ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1191 unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1193 // Must be addrmode4/6.
1194 MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1196 ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1197 if (!AFI->isThumbFunction())
1198 emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1199 Offset, Pred, PredReg, TII);
1201 assert(AFI->isThumb2Function());
1202 emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1203 Offset, Pred, PredReg, TII);
1205 // Update the original instruction to use the scratch register.
1206 MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);