1 //===- AArch64RegisterInfo.cpp - AArch64 Register Information -------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file contains the AArch64 implementation of the TargetRegisterInfo
12 //===----------------------------------------------------------------------===//
14 #include "AArch64RegisterInfo.h"
15 #include "AArch64FrameLowering.h"
16 #include "AArch64InstrInfo.h"
17 #include "AArch64MachineFunctionInfo.h"
18 #include "AArch64StackOffset.h"
19 #include "AArch64Subtarget.h"
20 #include "MCTargetDesc/AArch64AddressingModes.h"
21 #include "llvm/ADT/BitVector.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/CodeGen/MachineFrameInfo.h"
24 #include "llvm/CodeGen/MachineInstrBuilder.h"
25 #include "llvm/CodeGen/MachineRegisterInfo.h"
26 #include "llvm/CodeGen/RegisterScavenging.h"
27 #include "llvm/CodeGen/TargetFrameLowering.h"
28 #include "llvm/IR/DiagnosticInfo.h"
29 #include "llvm/IR/Function.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include "llvm/Target/TargetOptions.h"
35 #define GET_REGINFO_TARGET_DESC
36 #include "AArch64GenRegisterInfo.inc"
38 AArch64RegisterInfo::AArch64RegisterInfo(const Triple &TT)
39 : AArch64GenRegisterInfo(AArch64::LR), TT(TT) {
40 AArch64_MC::initLLVMToCVRegMapping(this);
43 static bool hasSVEArgsOrReturn(const MachineFunction *MF) {
44 const Function &F = MF->getFunction();
45 return isa<ScalableVectorType>(F.getReturnType()) ||
46 any_of(F.args(), [](const Argument &Arg) {
47 return isa<ScalableVectorType>(Arg.getType());
52 AArch64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
53 assert(MF && "Invalid MachineFunction pointer.");
55 if (MF->getFunction().getCallingConv() == CallingConv::GHC)
56 // GHC set of callee saved regs is empty as all those regs are
57 // used for passing STG regs around
58 return CSR_AArch64_NoRegs_SaveList;
59 if (MF->getFunction().getCallingConv() == CallingConv::AnyReg)
60 return CSR_AArch64_AllRegs_SaveList;
62 // Darwin has its own CSR_AArch64_AAPCS_SaveList, which means most CSR save
63 // lists depending on that will need to have their Darwin variant as well.
64 if (MF->getSubtarget<AArch64Subtarget>().isTargetDarwin())
65 return getDarwinCalleeSavedRegs(MF);
67 if (MF->getFunction().getCallingConv() == CallingConv::CFGuard_Check)
68 return CSR_Win_AArch64_CFGuard_Check_SaveList;
69 if (MF->getSubtarget<AArch64Subtarget>().isTargetWindows())
70 return CSR_Win_AArch64_AAPCS_SaveList;
71 if (MF->getFunction().getCallingConv() == CallingConv::AArch64_VectorCall)
72 return CSR_AArch64_AAVPCS_SaveList;
73 if (MF->getFunction().getCallingConv() == CallingConv::AArch64_SVE_VectorCall)
74 return CSR_AArch64_SVE_AAPCS_SaveList;
75 if (MF->getSubtarget<AArch64Subtarget>().getTargetLowering()
76 ->supportSwiftError() &&
77 MF->getFunction().getAttributes().hasAttrSomewhere(
78 Attribute::SwiftError))
79 return CSR_AArch64_AAPCS_SwiftError_SaveList;
80 if (MF->getFunction().getCallingConv() == CallingConv::PreserveMost)
81 return CSR_AArch64_RT_MostRegs_SaveList;
82 if (MF->getFunction().getCallingConv() == CallingConv::Win64)
83 // This is for OSes other than Windows; Windows is a separate case further
85 return CSR_AArch64_AAPCS_X18_SaveList;
86 if (hasSVEArgsOrReturn(MF))
87 return CSR_AArch64_SVE_AAPCS_SaveList;
88 return CSR_AArch64_AAPCS_SaveList;
92 AArch64RegisterInfo::getDarwinCalleeSavedRegs(const MachineFunction *MF) const {
93 assert(MF && "Invalid MachineFunction pointer.");
94 assert(MF->getSubtarget<AArch64Subtarget>().isTargetDarwin() &&
95 "Invalid subtarget for getDarwinCalleeSavedRegs");
97 if (MF->getFunction().getCallingConv() == CallingConv::CFGuard_Check)
99 "Calling convention CFGuard_Check is unsupported on Darwin.");
100 if (MF->getFunction().getCallingConv() == CallingConv::AArch64_VectorCall)
101 return CSR_Darwin_AArch64_AAVPCS_SaveList;
102 if (MF->getFunction().getCallingConv() == CallingConv::AArch64_SVE_VectorCall)
104 "Calling convention SVE_VectorCall is unsupported on Darwin.");
105 if (MF->getFunction().getCallingConv() == CallingConv::CXX_FAST_TLS)
106 return MF->getInfo<AArch64FunctionInfo>()->isSplitCSR()
107 ? CSR_Darwin_AArch64_CXX_TLS_PE_SaveList
108 : CSR_Darwin_AArch64_CXX_TLS_SaveList;
109 if (MF->getSubtarget<AArch64Subtarget>().getTargetLowering()
110 ->supportSwiftError() &&
111 MF->getFunction().getAttributes().hasAttrSomewhere(
112 Attribute::SwiftError))
113 return CSR_Darwin_AArch64_AAPCS_SwiftError_SaveList;
114 if (MF->getFunction().getCallingConv() == CallingConv::PreserveMost)
115 return CSR_Darwin_AArch64_RT_MostRegs_SaveList;
116 return CSR_Darwin_AArch64_AAPCS_SaveList;
119 const MCPhysReg *AArch64RegisterInfo::getCalleeSavedRegsViaCopy(
120 const MachineFunction *MF) const {
121 assert(MF && "Invalid MachineFunction pointer.");
122 if (MF->getFunction().getCallingConv() == CallingConv::CXX_FAST_TLS &&
123 MF->getInfo<AArch64FunctionInfo>()->isSplitCSR())
124 return CSR_Darwin_AArch64_CXX_TLS_ViaCopy_SaveList;
128 void AArch64RegisterInfo::UpdateCustomCalleeSavedRegs(
129 MachineFunction &MF) const {
130 const MCPhysReg *CSRs = getCalleeSavedRegs(&MF);
131 SmallVector<MCPhysReg, 32> UpdatedCSRs;
132 for (const MCPhysReg *I = CSRs; *I; ++I)
133 UpdatedCSRs.push_back(*I);
135 for (size_t i = 0; i < AArch64::GPR64commonRegClass.getNumRegs(); ++i) {
136 if (MF.getSubtarget<AArch64Subtarget>().isXRegCustomCalleeSaved(i)) {
137 UpdatedCSRs.push_back(AArch64::GPR64commonRegClass.getRegister(i));
140 // Register lists are zero-terminated.
141 UpdatedCSRs.push_back(0);
142 MF.getRegInfo().setCalleeSavedRegs(UpdatedCSRs);
145 const TargetRegisterClass *
146 AArch64RegisterInfo::getSubClassWithSubReg(const TargetRegisterClass *RC,
147 unsigned Idx) const {
148 // edge case for GPR/FPR register classes
149 if (RC == &AArch64::GPR32allRegClass && Idx == AArch64::hsub)
150 return &AArch64::FPR32RegClass;
151 else if (RC == &AArch64::GPR64allRegClass && Idx == AArch64::hsub)
152 return &AArch64::FPR64RegClass;
154 // Forward to TableGen's default version.
155 return AArch64GenRegisterInfo::getSubClassWithSubReg(RC, Idx);
159 AArch64RegisterInfo::getDarwinCallPreservedMask(const MachineFunction &MF,
160 CallingConv::ID CC) const {
161 assert(MF.getSubtarget<AArch64Subtarget>().isTargetDarwin() &&
162 "Invalid subtarget for getDarwinCallPreservedMask");
164 if (CC == CallingConv::CXX_FAST_TLS)
165 return CSR_Darwin_AArch64_CXX_TLS_RegMask;
166 if (CC == CallingConv::AArch64_VectorCall)
167 return CSR_Darwin_AArch64_AAVPCS_RegMask;
168 if (CC == CallingConv::AArch64_SVE_VectorCall)
170 "Calling convention SVE_VectorCall is unsupported on Darwin.");
171 if (CC == CallingConv::CFGuard_Check)
173 "Calling convention CFGuard_Check is unsupported on Darwin.");
174 if (MF.getSubtarget<AArch64Subtarget>()
176 ->supportSwiftError() &&
177 MF.getFunction().getAttributes().hasAttrSomewhere(Attribute::SwiftError))
178 return CSR_Darwin_AArch64_AAPCS_SwiftError_RegMask;
179 if (CC == CallingConv::PreserveMost)
180 return CSR_Darwin_AArch64_RT_MostRegs_RegMask;
181 return CSR_Darwin_AArch64_AAPCS_RegMask;
185 AArch64RegisterInfo::getCallPreservedMask(const MachineFunction &MF,
186 CallingConv::ID CC) const {
187 bool SCS = MF.getFunction().hasFnAttribute(Attribute::ShadowCallStack);
188 if (CC == CallingConv::GHC)
189 // This is academic because all GHC calls are (supposed to be) tail calls
190 return SCS ? CSR_AArch64_NoRegs_SCS_RegMask : CSR_AArch64_NoRegs_RegMask;
191 if (CC == CallingConv::AnyReg)
192 return SCS ? CSR_AArch64_AllRegs_SCS_RegMask : CSR_AArch64_AllRegs_RegMask;
194 // All the following calling conventions are handled differently on Darwin.
195 if (MF.getSubtarget<AArch64Subtarget>().isTargetDarwin()) {
197 report_fatal_error("ShadowCallStack attribute not supported on Darwin.");
198 return getDarwinCallPreservedMask(MF, CC);
201 if (CC == CallingConv::AArch64_VectorCall)
202 return SCS ? CSR_AArch64_AAVPCS_SCS_RegMask : CSR_AArch64_AAVPCS_RegMask;
203 if (CC == CallingConv::AArch64_SVE_VectorCall)
204 return SCS ? CSR_AArch64_SVE_AAPCS_SCS_RegMask
205 : CSR_AArch64_SVE_AAPCS_RegMask;
206 if (CC == CallingConv::CFGuard_Check)
207 return CSR_Win_AArch64_CFGuard_Check_RegMask;
208 if (MF.getSubtarget<AArch64Subtarget>().getTargetLowering()
209 ->supportSwiftError() &&
210 MF.getFunction().getAttributes().hasAttrSomewhere(Attribute::SwiftError))
211 return SCS ? CSR_AArch64_AAPCS_SwiftError_SCS_RegMask
212 : CSR_AArch64_AAPCS_SwiftError_RegMask;
213 if (CC == CallingConv::PreserveMost)
214 return SCS ? CSR_AArch64_RT_MostRegs_SCS_RegMask
215 : CSR_AArch64_RT_MostRegs_RegMask;
217 return SCS ? CSR_AArch64_AAPCS_SCS_RegMask : CSR_AArch64_AAPCS_RegMask;
220 const uint32_t *AArch64RegisterInfo::getTLSCallPreservedMask() const {
222 return CSR_Darwin_AArch64_TLS_RegMask;
224 assert(TT.isOSBinFormatELF() && "Invalid target");
225 return CSR_AArch64_TLS_ELF_RegMask;
228 void AArch64RegisterInfo::UpdateCustomCallPreservedMask(MachineFunction &MF,
229 const uint32_t **Mask) const {
230 uint32_t *UpdatedMask = MF.allocateRegMask();
231 unsigned RegMaskSize = MachineOperand::getRegMaskSize(getNumRegs());
232 memcpy(UpdatedMask, *Mask, sizeof(UpdatedMask[0]) * RegMaskSize);
234 for (size_t i = 0; i < AArch64::GPR64commonRegClass.getNumRegs(); ++i) {
235 if (MF.getSubtarget<AArch64Subtarget>().isXRegCustomCalleeSaved(i)) {
236 for (MCSubRegIterator SubReg(AArch64::GPR64commonRegClass.getRegister(i),
238 SubReg.isValid(); ++SubReg) {
239 // See TargetRegisterInfo::getCallPreservedMask for how to interpret the
241 UpdatedMask[*SubReg / 32] |= 1u << (*SubReg % 32);
248 const uint32_t *AArch64RegisterInfo::getNoPreservedMask() const {
249 return CSR_AArch64_NoRegs_RegMask;
253 AArch64RegisterInfo::getThisReturnPreservedMask(const MachineFunction &MF,
254 CallingConv::ID CC) const {
255 // This should return a register mask that is the same as that returned by
256 // getCallPreservedMask but that additionally preserves the register used for
257 // the first i64 argument (which must also be the register used to return a
258 // single i64 return value)
260 // In case that the calling convention does not use the same register for
261 // both, the function should return NULL (does not currently apply)
262 assert(CC != CallingConv::GHC && "should not be GHC calling convention.");
263 if (MF.getSubtarget<AArch64Subtarget>().isTargetDarwin())
264 return CSR_Darwin_AArch64_AAPCS_ThisReturn_RegMask;
265 return CSR_AArch64_AAPCS_ThisReturn_RegMask;
268 const uint32_t *AArch64RegisterInfo::getWindowsStackProbePreservedMask() const {
269 return CSR_AArch64_StackProbe_Windows_RegMask;
273 AArch64RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
274 const AArch64FrameLowering *TFI = getFrameLowering(MF);
276 // FIXME: avoid re-calculating this every time.
277 BitVector Reserved(getNumRegs());
278 markSuperRegs(Reserved, AArch64::WSP);
279 markSuperRegs(Reserved, AArch64::WZR);
281 if (TFI->hasFP(MF) || TT.isOSDarwin())
282 markSuperRegs(Reserved, AArch64::W29);
284 for (size_t i = 0; i < AArch64::GPR32commonRegClass.getNumRegs(); ++i) {
285 if (MF.getSubtarget<AArch64Subtarget>().isXRegisterReserved(i))
286 markSuperRegs(Reserved, AArch64::GPR32commonRegClass.getRegister(i));
289 if (hasBasePointer(MF))
290 markSuperRegs(Reserved, AArch64::W19);
292 // SLH uses register W16/X16 as the taint register.
293 if (MF.getFunction().hasFnAttribute(Attribute::SpeculativeLoadHardening))
294 markSuperRegs(Reserved, AArch64::W16);
296 assert(checkAllSuperRegsMarked(Reserved));
300 bool AArch64RegisterInfo::isReservedReg(const MachineFunction &MF,
301 MCRegister Reg) const {
302 return getReservedRegs(MF)[Reg];
305 bool AArch64RegisterInfo::isAnyArgRegReserved(const MachineFunction &MF) const {
306 return std::any_of(std::begin(*AArch64::GPR64argRegClass.MC),
307 std::end(*AArch64::GPR64argRegClass.MC),
308 [this, &MF](MCPhysReg r){return isReservedReg(MF, r);});
311 void AArch64RegisterInfo::emitReservedArgRegCallError(
312 const MachineFunction &MF) const {
313 const Function &F = MF.getFunction();
314 F.getContext().diagnose(DiagnosticInfoUnsupported{F, "AArch64 doesn't support"
315 " function calls if any of the argument registers is reserved."});
318 bool AArch64RegisterInfo::isAsmClobberable(const MachineFunction &MF,
319 MCRegister PhysReg) const {
320 return !isReservedReg(MF, PhysReg);
323 bool AArch64RegisterInfo::isConstantPhysReg(MCRegister PhysReg) const {
324 return PhysReg == AArch64::WZR || PhysReg == AArch64::XZR;
327 const TargetRegisterClass *
328 AArch64RegisterInfo::getPointerRegClass(const MachineFunction &MF,
329 unsigned Kind) const {
330 return &AArch64::GPR64spRegClass;
333 const TargetRegisterClass *
334 AArch64RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
335 if (RC == &AArch64::CCRRegClass)
336 return &AArch64::GPR64RegClass; // Only MSR & MRS copy NZCV.
340 unsigned AArch64RegisterInfo::getBaseRegister() const { return AArch64::X19; }
342 bool AArch64RegisterInfo::hasBasePointer(const MachineFunction &MF) const {
343 const MachineFrameInfo &MFI = MF.getFrameInfo();
345 // In the presence of variable sized objects or funclets, if the fixed stack
346 // size is large enough that referencing from the FP won't result in things
347 // being in range relatively often, we can use a base pointer to allow access
348 // from the other direction like the SP normally works.
350 // Furthermore, if both variable sized objects are present, and the
351 // stack needs to be dynamically re-aligned, the base pointer is the only
352 // reliable way to reference the locals.
353 if (MFI.hasVarSizedObjects() || MF.hasEHFunclets()) {
354 if (needsStackRealignment(MF))
357 if (MF.getSubtarget<AArch64Subtarget>().hasSVE()) {
358 const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
359 // Frames that have variable sized objects and scalable SVE objects,
360 // should always use a basepointer.
361 if (!AFI->hasCalculatedStackSizeSVE() || AFI->getStackSizeSVE())
365 // Conservatively estimate whether the negative offset from the frame
366 // pointer will be sufficient to reach. If a function has a smallish
367 // frame, it's less likely to have lots of spills and callee saved
368 // space, so it's all more likely to be within range of the frame pointer.
369 // If it's wrong, we'll materialize the constant and still get to the
370 // object; it's just suboptimal. Negative offsets use the unscaled
371 // load/store instructions, which have a 9-bit signed immediate.
372 return MFI.getLocalFrameSize() >= 256;
379 AArch64RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
380 const AArch64FrameLowering *TFI = getFrameLowering(MF);
381 return TFI->hasFP(MF) ? AArch64::FP : AArch64::SP;
384 bool AArch64RegisterInfo::requiresRegisterScavenging(
385 const MachineFunction &MF) const {
389 bool AArch64RegisterInfo::requiresVirtualBaseRegisters(
390 const MachineFunction &MF) const {
395 AArch64RegisterInfo::useFPForScavengingIndex(const MachineFunction &MF) const {
396 // This function indicates whether the emergency spillslot should be placed
397 // close to the beginning of the stackframe (closer to FP) or the end
400 // The beginning works most reliably if we have a frame pointer.
401 // In the presence of any non-constant space between FP and locals,
402 // (e.g. in case of stack realignment or a scalable SVE area), it is
403 // better to use SP or BP.
404 const AArch64FrameLowering &TFI = *getFrameLowering(MF);
405 const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
406 assert((!MF.getSubtarget<AArch64Subtarget>().hasSVE() ||
407 AFI->hasCalculatedStackSizeSVE()) &&
408 "Expected SVE area to be calculated by this point");
409 return TFI.hasFP(MF) && !needsStackRealignment(MF) && !AFI->getStackSizeSVE();
412 bool AArch64RegisterInfo::requiresFrameIndexScavenging(
413 const MachineFunction &MF) const {
418 AArch64RegisterInfo::cannotEliminateFrame(const MachineFunction &MF) const {
419 const MachineFrameInfo &MFI = MF.getFrameInfo();
420 if (MF.getTarget().Options.DisableFramePointerElim(MF) && MFI.adjustsStack())
422 return MFI.hasVarSizedObjects() || MFI.isFrameAddressTaken();
425 /// needsFrameBaseReg - Returns true if the instruction's frame index
426 /// reference would be better served by a base register other than FP
427 /// or SP. Used by LocalStackFrameAllocation to determine which frame index
428 /// references it should create new base registers for.
429 bool AArch64RegisterInfo::needsFrameBaseReg(MachineInstr *MI,
430 int64_t Offset) const {
431 for (unsigned i = 0; !MI->getOperand(i).isFI(); ++i)
432 assert(i < MI->getNumOperands() &&
433 "Instr doesn't have FrameIndex operand!");
435 // It's the load/store FI references that cause issues, as it can be difficult
436 // to materialize the offset if it won't fit in the literal field. Estimate
437 // based on the size of the local frame and some conservative assumptions
438 // about the rest of the stack frame (note, this is pre-regalloc, so
439 // we don't know everything for certain yet) whether this offset is likely
440 // to be out of range of the immediate. Return true if so.
442 // We only generate virtual base registers for loads and stores, so
443 // return false for everything else.
444 if (!MI->mayLoad() && !MI->mayStore())
447 // Without a virtual base register, if the function has variable sized
448 // objects, all fixed-size local references will be via the frame pointer,
449 // Approximate the offset and see if it's legal for the instruction.
450 // Note that the incoming offset is based on the SP value at function entry,
451 // so it'll be negative.
452 MachineFunction &MF = *MI->getParent()->getParent();
453 const AArch64FrameLowering *TFI = getFrameLowering(MF);
454 MachineFrameInfo &MFI = MF.getFrameInfo();
456 // Estimate an offset from the frame pointer.
457 // Conservatively assume all GPR callee-saved registers get pushed.
458 // FP, LR, X19-X28, D8-D15. 64-bits each.
459 int64_t FPOffset = Offset - 16 * 20;
460 // Estimate an offset from the stack pointer.
461 // The incoming offset is relating to the SP at the start of the function,
462 // but when we access the local it'll be relative to the SP after local
463 // allocation, so adjust our SP-relative offset by that allocation size.
464 Offset += MFI.getLocalFrameSize();
465 // Assume that we'll have at least some spill slots allocated.
466 // FIXME: This is a total SWAG number. We should run some statistics
467 // and pick a real one.
468 Offset += 128; // 128 bytes of spill slots
470 // If there is a frame pointer, try using it.
471 // The FP is only available if there is no dynamic realignment. We
472 // don't know for sure yet whether we'll need that, so we guess based
473 // on whether there are any local variables that would trigger it.
474 if (TFI->hasFP(MF) && isFrameOffsetLegal(MI, AArch64::FP, FPOffset))
477 // If we can reference via the stack pointer or base pointer, try that.
478 // FIXME: This (and the code that resolves the references) can be improved
479 // to only disallow SP relative references in the live range of
480 // the VLA(s). In practice, it's unclear how much difference that
481 // would make, but it may be worth doing.
482 if (isFrameOffsetLegal(MI, AArch64::SP, Offset))
485 // If even offset 0 is illegal, we don't want a virtual base register.
486 if (!isFrameOffsetLegal(MI, AArch64::SP, 0))
489 // The offset likely isn't legal; we want to allocate a virtual base register.
493 bool AArch64RegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
495 int64_t Offset) const {
496 assert(MI && "Unable to get the legal offset for nil instruction.");
497 StackOffset SaveOffset(Offset, MVT::i8);
498 return isAArch64FrameOffsetLegal(*MI, SaveOffset) & AArch64FrameOffsetIsLegal;
501 /// Insert defining instruction(s) for BaseReg to be a pointer to FrameIdx
502 /// at the beginning of the basic block.
503 void AArch64RegisterInfo::materializeFrameBaseRegister(MachineBasicBlock *MBB,
506 int64_t Offset) const {
507 MachineBasicBlock::iterator Ins = MBB->begin();
508 DebugLoc DL; // Defaults to "unknown"
509 if (Ins != MBB->end())
510 DL = Ins->getDebugLoc();
511 const MachineFunction &MF = *MBB->getParent();
512 const AArch64InstrInfo *TII =
513 MF.getSubtarget<AArch64Subtarget>().getInstrInfo();
514 const MCInstrDesc &MCID = TII->get(AArch64::ADDXri);
515 MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
516 MRI.constrainRegClass(BaseReg, TII->getRegClass(MCID, 0, this, MF));
517 unsigned Shifter = AArch64_AM::getShifterImm(AArch64_AM::LSL, 0);
519 BuildMI(*MBB, Ins, DL, MCID, BaseReg)
520 .addFrameIndex(FrameIdx)
525 void AArch64RegisterInfo::resolveFrameIndex(MachineInstr &MI, Register BaseReg,
526 int64_t Offset) const {
527 // ARM doesn't need the general 64-bit offsets
528 StackOffset Off(Offset, MVT::i8);
532 while (!MI.getOperand(i).isFI()) {
534 assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
536 const MachineFunction *MF = MI.getParent()->getParent();
537 const AArch64InstrInfo *TII =
538 MF->getSubtarget<AArch64Subtarget>().getInstrInfo();
539 bool Done = rewriteAArch64FrameIndex(MI, i, BaseReg, Off, TII);
540 assert(Done && "Unable to resolve frame index!");
544 // Create a scratch register for the frame index elimination in an instruction.
545 // This function has special handling of stack tagging loop pseudos, in which
546 // case it can also change the instruction opcode (but not the operands).
548 createScratchRegisterForInstruction(MachineInstr &MI,
549 const AArch64InstrInfo *TII) {
550 // ST*Gloop have a reserved scratch register in operand 1. Use it, and also
551 // replace the instruction with the writeback variant because it will now
552 // satisfy the operand constraints for it.
553 if (MI.getOpcode() == AArch64::STGloop) {
554 MI.setDesc(TII->get(AArch64::STGloop_wback));
555 return MI.getOperand(1).getReg();
556 } else if (MI.getOpcode() == AArch64::STZGloop) {
557 MI.setDesc(TII->get(AArch64::STZGloop_wback));
558 return MI.getOperand(1).getReg();
560 return MI.getMF()->getRegInfo().createVirtualRegister(
561 &AArch64::GPR64RegClass);
565 void AArch64RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
566 int SPAdj, unsigned FIOperandNum,
567 RegScavenger *RS) const {
568 assert(SPAdj == 0 && "Unexpected");
570 MachineInstr &MI = *II;
571 MachineBasicBlock &MBB = *MI.getParent();
572 MachineFunction &MF = *MBB.getParent();
573 const MachineFrameInfo &MFI = MF.getFrameInfo();
574 const AArch64InstrInfo *TII =
575 MF.getSubtarget<AArch64Subtarget>().getInstrInfo();
576 const AArch64FrameLowering *TFI = getFrameLowering(MF);
578 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
580 MI.getOperand(FIOperandNum).getTargetFlags() & AArch64II::MO_TAGGED;
583 // Special handling of dbg_value, stackmap and patchpoint instructions.
584 if (MI.isDebugValue() || MI.getOpcode() == TargetOpcode::STACKMAP ||
585 MI.getOpcode() == TargetOpcode::PATCHPOINT) {
587 TFI->resolveFrameIndexReference(MF, FrameIndex, FrameReg,
590 Offset += StackOffset(MI.getOperand(FIOperandNum + 1).getImm(), MVT::i8);
591 MI.getOperand(FIOperandNum).ChangeToRegister(FrameReg, false /*isDef*/);
592 MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset.getBytes());
596 if (MI.getOpcode() == TargetOpcode::LOCAL_ESCAPE) {
597 MachineOperand &FI = MI.getOperand(FIOperandNum);
598 int Offset = TFI->getNonLocalFrameIndexReference(MF, FrameIndex);
599 FI.ChangeToImmediate(Offset);
604 if (MI.getOpcode() == AArch64::TAGPstack) {
605 // TAGPstack must use the virtual frame register in its 3rd operand.
606 const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
607 FrameReg = MI.getOperand(3).getReg();
608 Offset = {MFI.getObjectOffset(FrameIndex) +
609 AFI->getTaggedBasePointerOffset(),
612 StackOffset SPOffset = {
613 MFI.getObjectOffset(FrameIndex) + (int64_t)MFI.getStackSize(), MVT::i8};
614 if (MFI.hasVarSizedObjects() ||
615 isAArch64FrameOffsetLegal(MI, SPOffset, nullptr, nullptr, nullptr) !=
616 (AArch64FrameOffsetCanUpdate | AArch64FrameOffsetIsLegal)) {
617 // Can't update to SP + offset in place. Precalculate the tagged pointer
618 // in a scratch register.
619 Offset = TFI->resolveFrameIndexReference(
620 MF, FrameIndex, FrameReg, /*PreferFP=*/false, /*ForSimm=*/true);
621 Register ScratchReg =
622 MF.getRegInfo().createVirtualRegister(&AArch64::GPR64RegClass);
623 emitFrameOffset(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg, Offset,
625 BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(AArch64::LDG), ScratchReg)
629 MI.getOperand(FIOperandNum)
630 .ChangeToRegister(ScratchReg, false, false, true);
633 FrameReg = AArch64::SP;
634 Offset = {MFI.getObjectOffset(FrameIndex) + (int64_t)MFI.getStackSize(),
637 Offset = TFI->resolveFrameIndexReference(
638 MF, FrameIndex, FrameReg, /*PreferFP=*/false, /*ForSimm=*/true);
641 // Modify MI as necessary to handle as much of 'Offset' as possible
642 if (rewriteAArch64FrameIndex(MI, FIOperandNum, FrameReg, Offset, TII))
645 assert((!RS || !RS->isScavengingFrameIndex(FrameIndex)) &&
646 "Emergency spill slot is out of reach");
648 // If we get here, the immediate doesn't fit into the instruction. We folded
649 // as much as possible above. Handle the rest, providing a register that is
651 Register ScratchReg = createScratchRegisterForInstruction(MI, TII);
652 emitFrameOffset(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg, Offset, TII);
653 MI.getOperand(FIOperandNum).ChangeToRegister(ScratchReg, false, false, true);
656 unsigned AArch64RegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
657 MachineFunction &MF) const {
658 const AArch64FrameLowering *TFI = getFrameLowering(MF);
660 switch (RC->getID()) {
663 case AArch64::GPR32RegClassID:
664 case AArch64::GPR32spRegClassID:
665 case AArch64::GPR32allRegClassID:
666 case AArch64::GPR64spRegClassID:
667 case AArch64::GPR64allRegClassID:
668 case AArch64::GPR64RegClassID:
669 case AArch64::GPR32commonRegClassID:
670 case AArch64::GPR64commonRegClassID:
671 return 32 - 1 // XZR/SP
672 - (TFI->hasFP(MF) || TT.isOSDarwin()) // FP
673 - MF.getSubtarget<AArch64Subtarget>().getNumXRegisterReserved()
674 - hasBasePointer(MF); // X19
675 case AArch64::FPR8RegClassID:
676 case AArch64::FPR16RegClassID:
677 case AArch64::FPR32RegClassID:
678 case AArch64::FPR64RegClassID:
679 case AArch64::FPR128RegClassID:
682 case AArch64::DDRegClassID:
683 case AArch64::DDDRegClassID:
684 case AArch64::DDDDRegClassID:
685 case AArch64::QQRegClassID:
686 case AArch64::QQQRegClassID:
687 case AArch64::QQQQRegClassID:
690 case AArch64::FPR128_loRegClassID:
691 case AArch64::FPR64_loRegClassID:
692 case AArch64::FPR16_loRegClassID:
697 unsigned AArch64RegisterInfo::getLocalAddressRegister(
698 const MachineFunction &MF) const {
699 const auto &MFI = MF.getFrameInfo();
700 if (!MF.hasEHFunclets() && !MFI.hasVarSizedObjects())
702 else if (needsStackRealignment(MF))
703 return getBaseRegister();
704 return getFrameRegister(MF);