AArch64AsmPrinter.cpp

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//===- AArch64AsmPrinter.cpp - AArch64 LLVM assembly writer ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to the AArch64 assembly language.
//
//===----------------------------------------------------------------------===//
 
#include "AArch64.h"
#include "AArch64MCInstLower.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64RegisterInfo.h"
#include "AArch64Subtarget.h"
#include "AArch64TargetObjectFile.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "MCTargetDesc/AArch64InstPrinter.h"
#include "MCTargetDesc/AArch64MCAsmInfo.h"
#include "MCTargetDesc/AArch64MCTargetDesc.h"
#include "MCTargetDesc/AArch64TargetStreamer.h"
#include "TargetInfo/AArch64TargetInfo.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/FaultMaps.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
#include <cassert>
#include <cstdint>
#include <map>
#include <memory>
 
using namespace llvm;
 
#define DEBUG_TYPE "AArch64AsmPrinter"
 
// Doesn't count FPR128 ZCZ instructions which are handled
// by TableGen pattern matching
STATISTIC(NumZCZeroingInstrsFPR,
          "Number of zero-cycle FPR zeroing instructions expanded from "
          "canonical pseudo instructions");
 
enum PtrauthCheckMode { Default, Unchecked, Poison, Trap };
static cl::opt<PtrauthCheckMode> PtrauthAuthChecks(
    "aarch64-ptrauth-auth-checks", cl::Hidden,
    cl::values(clEnumValN(Unchecked, "none", "don't test for failure"),
               clEnumValN(Poison, "poison", "poison on failure"),
               clEnumValN(Trap, "trap", "trap on failure")),
    cl::desc("Check pointer authentication auth/resign failures"),
    cl::init(Default));
 
namespace {
 
class AArch64AsmPrinter : public AsmPrinter {
  AArch64MCInstLower MCInstLowering;
  FaultMaps FM;
  const AArch64Subtarget *STI;
  bool ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags = false;
#ifndef NDEBUG
  unsigned InstsEmitted;
#endif
  bool EnableImportCallOptimization = false;
  MapVector<MCSection *, std::vector<std::pair<MCSymbol *, MCSymbol *>>>
      SectionToImportedFunctionCalls;
  unsigned PAuthIFuncNextUniqueID = 1;
 
public:
  static char ID;
 
  AArch64AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
      : AsmPrinter(TM, std::move(Streamer), ID),
        MCInstLowering(OutContext, *this), FM(*this) {}
 
  StringRef getPassName() const override { return "AArch64 Assembly Printer"; }
 
  /// Wrapper for MCInstLowering.lowerOperand() for the
  /// tblgen'erated pseudo lowering.
  bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp) const {
    return MCInstLowering.lowerOperand(MO, MCOp);
  }
 
  const MCExpr *lowerConstantPtrAuth(const ConstantPtrAuth &CPA) override;
 
  const MCExpr *lowerBlockAddressConstant(const BlockAddress &BA) override;
 
  void emitStartOfAsmFile(Module &M) override;
  void emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
                         ArrayRef<unsigned> JumpTableIndices) override;
  std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
             codeview::JumpTableEntrySize>
  getCodeViewJumpTableInfo(int JTI, const MachineInstr *BranchInstr,
                           const MCSymbol *BranchLabel) const override;
 
  void emitFunctionEntryLabel() override;
 
  void emitXXStructor(const DataLayout &DL, const Constant *CV) override;
 
  void LowerJumpTableDest(MCStreamer &OutStreamer, const MachineInstr &MI);
 
  void LowerHardenedBRJumpTable(const MachineInstr &MI);
 
  void LowerMOPS(MCStreamer &OutStreamer, const MachineInstr &MI);
 
  void LowerSTACKMAP(MCStreamer &OutStreamer, StackMaps &SM,
                     const MachineInstr &MI);
  void LowerPATCHPOINT(MCStreamer &OutStreamer, StackMaps &SM,
                       const MachineInstr &MI);
  void LowerSTATEPOINT(MCStreamer &OutStreamer, StackMaps &SM,
                       const MachineInstr &MI);
  void LowerFAULTING_OP(const MachineInstr &MI);
 
  void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI);
  void LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI);
  void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI);
  void LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI, bool Typed);
 
  typedef std::tuple<unsigned, bool, uint32_t, bool, uint64_t>
      HwasanMemaccessTuple;
  std::map<HwasanMemaccessTuple, MCSymbol *> HwasanMemaccessSymbols;
  void LowerKCFI_CHECK(const MachineInstr &MI);
  void LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI);
  void emitHwasanMemaccessSymbols(Module &M);
 
  void emitSled(const MachineInstr &MI, SledKind Kind);
 
  // Returns whether Reg may be used to store sensitive temporary values when
  // expanding PtrAuth pseudos. Some OSes may take extra care to protect a
  // small subset of GPRs on context switches - use these registers then.
  //
  // If there are no preferred registers, returns true for any Reg.
  bool isPtrauthRegSafe(Register Reg) const {
    if (STI->isX16X17Safer())
      return Reg == AArch64::X16 || Reg == AArch64::X17;
 
    return true;
  }
 
  // Emit the sequence for BRA/BLRA (authenticate + branch/call).
  void emitPtrauthBranch(const MachineInstr *MI);
 
  void emitPtrauthCheckAuthenticatedValue(Register TestedReg,
                                          Register ScratchReg,
                                          AArch64PACKey::ID Key,
                                          AArch64PAuth::AuthCheckMethod Method,
                                          const MCSymbol *OnFailure = nullptr);
 
  // Check authenticated LR before tail calling.
  void emitPtrauthTailCallHardening(const MachineInstr *TC);
 
  struct PtrAuthSchema {
    PtrAuthSchema(AArch64PACKey::ID Key, uint64_t IntDisc,
                  const MachineOperand &AddrDiscOp);
 
    AArch64PACKey::ID Key;
    uint64_t IntDisc;
    Register AddrDisc;
    bool AddrDiscIsKilled;
  };
 
  // Emit the sequence for AUT or AUTPAC.
  void emitPtrauthAuthResign(Register Pointer, Register Scratch,
                             PtrAuthSchema AuthSchema,
                             std::optional<PtrAuthSchema> SignSchema,
                             Value *DS);
 
  // Emit R_AARCH64_PATCHINST, the deactivation symbol relocation. Returns true
  // if no instruction should be emitted because the deactivation symbol is
  // defined in the current module so this function emitted a NOP instead.
  bool emitDeactivationSymbolRelocation(Value *DS);
 
  // Emit the sequence for PAC.
  void emitPtrauthSign(const MachineInstr *MI);
 
  // Emit the sequence to compute the discriminator.
  //
  // The Scratch register passed to this function must be safe, as returned by
  // isPtrauthRegSafe(ScratchReg).
  //
  // The returned register is either ScratchReg, AddrDisc, or XZR. Furthermore,
  // it is guaranteed to be safe (or XZR), with the only exception of
  // passing-through an *unmodified* unsafe AddrDisc register.
  //
  // If the expanded pseudo is allowed to clobber AddrDisc register, setting
  // MayClobberAddrDisc may save one MOV instruction, provided
  // isPtrauthRegSafe(AddrDisc) is true:
  //
  //   mov   x17, x16
  //   movk  x17, #1234, lsl #48
  //   ; x16 is not used anymore
  //
  // can be replaced by
  //
  //   movk  x16, #1234, lsl #48
  Register emitPtrauthDiscriminator(uint64_t Disc, Register AddrDisc,
                                    Register ScratchReg,
                                    bool MayClobberAddrDisc = false);
 
  // Emit the sequence for LOADauthptrstatic
  void LowerLOADauthptrstatic(const MachineInstr &MI);
 
  // Emit the sequence for LOADgotPAC/MOVaddrPAC (either GOT adrp-ldr or
  // adrp-add followed by PAC sign)
  void LowerMOVaddrPAC(const MachineInstr &MI);
 
  // Emit the sequence for LOADgotAUTH (load signed pointer from signed ELF GOT
  // and authenticate it with, if FPAC bit is not set, check+trap sequence after
  // authenticating)
  void LowerLOADgotAUTH(const MachineInstr &MI);
 
  void emitAddImm(MCRegister Val, int64_t Addend, MCRegister Tmp);
  void emitAddress(MCRegister Reg, const MCExpr *Expr, MCRegister Tmp,
                   bool DSOLocal, const MCSubtargetInfo &STI);
 
  const MCExpr *emitPAuthRelocationAsIRelative(
      const MCExpr *Target, uint64_t Disc, AArch64PACKey::ID KeyID,
      bool HasAddressDiversity, bool IsDSOLocal, const MCExpr *DSExpr);
 
  /// tblgen'erated driver function for lowering simple MI->MC
  /// pseudo instructions.
  bool lowerPseudoInstExpansion(const MachineInstr *MI, MCInst &Inst);
 
  // Emit Build Attributes
  void emitAttributes(unsigned Flags, uint64_t PAuthABIPlatform,
                      uint64_t PAuthABIVersion, AArch64TargetStreamer *TS);
 
  // Emit expansion of Compare-and-branch pseudo instructions
  void emitCBPseudoExpansion(const MachineInstr *MI);
 
  void EmitToStreamer(MCStreamer &S, const MCInst &Inst);
  void EmitToStreamer(const MCInst &Inst) {
    EmitToStreamer(*OutStreamer, Inst);
  }
 
  void emitInstruction(const MachineInstr *MI) override;
 
  void emitFunctionHeaderComment() override;
 
  void getAnalysisUsage(AnalysisUsage &AU) const override {
    AsmPrinter::getAnalysisUsage(AU);
    AU.setPreservesAll();
  }
 
  bool runOnMachineFunction(MachineFunction &MF) override {
    if (auto *PSIW = getAnalysisIfAvailable<ProfileSummaryInfoWrapperPass>())
      PSI = &PSIW->getPSI();
    if (auto *SDPIW =
            getAnalysisIfAvailable<StaticDataProfileInfoWrapperPass>())
      SDPI = &SDPIW->getStaticDataProfileInfo();
 
    AArch64FI = MF.getInfo<AArch64FunctionInfo>();
    STI = &MF.getSubtarget<AArch64Subtarget>();
 
    SetupMachineFunction(MF);
 
    if (STI->isTargetCOFF()) {
      bool Local = MF.getFunction().hasLocalLinkage();
      COFF::SymbolStorageClass Scl =
          Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL;
      int Type =
        COFF::IMAGE_SYM_DTYPE_FUNCTION << COFF::SCT_COMPLEX_TYPE_SHIFT;
 
      OutStreamer->beginCOFFSymbolDef(CurrentFnSym);
      OutStreamer->emitCOFFSymbolStorageClass(Scl);
      OutStreamer->emitCOFFSymbolType(Type);
      OutStreamer->endCOFFSymbolDef();
    }
 
    // Emit the rest of the function body.
    emitFunctionBody();
 
    // Emit the XRay table for this function.
    emitXRayTable();
 
    // We didn't modify anything.
    return false;
  }
 
  const MCExpr *lowerConstant(const Constant *CV,
                              const Constant *BaseCV = nullptr,
                              uint64_t Offset = 0) override;
 
private:
  void printOperand(const MachineInstr *MI, unsigned OpNum, raw_ostream &O);
  bool printAsmMRegister(const MachineOperand &MO, char Mode, raw_ostream &O);
  bool printAsmRegInClass(const MachineOperand &MO,
                          const TargetRegisterClass *RC, unsigned AltName,
                          raw_ostream &O);
 
  bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
                       const char *ExtraCode, raw_ostream &O) override;
  bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
                             const char *ExtraCode, raw_ostream &O) override;
 
  void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
 
  void emitFunctionBodyEnd() override;
  void emitGlobalAlias(const Module &M, const GlobalAlias &GA) override;
 
  MCSymbol *GetCPISymbol(unsigned CPID) const override;
  void emitEndOfAsmFile(Module &M) override;
 
  AArch64FunctionInfo *AArch64FI = nullptr;
 
  /// Emit the LOHs contained in AArch64FI.
  void emitLOHs();
 
  void emitMovXReg(Register Dest, Register Src);
  void emitMOVZ(Register Dest, uint64_t Imm, unsigned Shift);
  void emitMOVK(Register Dest, uint64_t Imm, unsigned Shift);
 
  void emitAUT(AArch64PACKey::ID Key, Register Pointer, Register Disc);
  void emitPAC(AArch64PACKey::ID Key, Register Pointer, Register Disc);
  void emitBLRA(bool IsCall, AArch64PACKey::ID Key, Register Target,
                Register Disc);
 
  /// Emit instruction to set float register to zero.
  void emitFMov0(const MachineInstr &MI);
  void emitFMov0AsFMov(const MachineInstr &MI, Register DestReg);
 
  using MInstToMCSymbol = std::map<const MachineInstr *, MCSymbol *>;
 
  MInstToMCSymbol LOHInstToLabel;
 
  bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const override {
    return ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags;
  }
 
  const MCSubtargetInfo *getIFuncMCSubtargetInfo() const override {
    assert(STI);
    return STI;
  }
  void emitMachOIFuncStubBody(Module &M, const GlobalIFunc &GI,
                              MCSymbol *LazyPointer) override;
  void emitMachOIFuncStubHelperBody(Module &M, const GlobalIFunc &GI,
                                    MCSymbol *LazyPointer) override;
 
  /// Checks if this instruction is part of a sequence that is eligle for import
  /// call optimization and, if so, records it to be emitted in the import call
  /// section.
  void recordIfImportCall(const MachineInstr *BranchInst);
};
 
} // end anonymous namespace
 
void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
  const Triple &TT = TM.getTargetTriple();
 
  if (TT.isOSBinFormatCOFF()) {
    emitCOFFFeatureSymbol(M);
    emitCOFFReplaceableFunctionData(M);
 
    if (M.getModuleFlag("import-call-optimization"))
      EnableImportCallOptimization = true;
  }
 
  if (!TT.isOSBinFormatELF())
    return;
 
  // For emitting build attributes and .note.gnu.property section
  auto *TS =
      static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
  // Assemble feature flags that may require creation of build attributes and a
  // note section.
  unsigned BAFlags = 0;
  unsigned GNUFlags = 0;
  if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
          M.getModuleFlag("branch-target-enforcement"))) {
    if (!BTE->isZero()) {
      BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_BTI_Flag;
      GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
    }
  }
 
  if (const auto *GCS = mdconst::extract_or_null<ConstantInt>(
          M.getModuleFlag("guarded-control-stack"))) {
    if (!GCS->isZero()) {
      BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_GCS_Flag;
      GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
    }
  }
 
  if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
          M.getModuleFlag("sign-return-address"))) {
    if (!Sign->isZero()) {
      BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_PAC_Flag;
      GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
    }
  }
 
  uint64_t PAuthABIPlatform = -1;
  if (const auto *PAP = mdconst::extract_or_null<ConstantInt>(
          M.getModuleFlag("aarch64-elf-pauthabi-platform"))) {
    PAuthABIPlatform = PAP->getZExtValue();
  }
 
  uint64_t PAuthABIVersion = -1;
  if (const auto *PAV = mdconst::extract_or_null<ConstantInt>(
          M.getModuleFlag("aarch64-elf-pauthabi-version"))) {
    PAuthABIVersion = PAV->getZExtValue();
  }
 
  // Emit AArch64 Build Attributes
  emitAttributes(BAFlags, PAuthABIPlatform, PAuthABIVersion, TS);
  // Emit a .note.gnu.property section with the flags.
  TS->emitNoteSection(GNUFlags, PAuthABIPlatform, PAuthABIVersion);
}
 
void AArch64AsmPrinter::emitFunctionHeaderComment() {
  const AArch64FunctionInfo *FI = MF->getInfo<AArch64FunctionInfo>();
  std::optional<std::string> OutlinerString = FI->getOutliningStyle();
  if (OutlinerString != std::nullopt)
    OutStreamer->getCommentOS() << ' ' << OutlinerString;
}
 
void AArch64AsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI)
{
  const Function &F = MF->getFunction();
  if (F.hasFnAttribute("patchable-function-entry")) {
    unsigned Num;
    if (F.getFnAttribute("patchable-function-entry")
            .getValueAsString()
            .getAsInteger(10, Num))
      return;
    emitNops(Num);
    return;
  }
 
  emitSled(MI, SledKind::FUNCTION_ENTER);
}
 
void AArch64AsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI) {
  emitSled(MI, SledKind::FUNCTION_EXIT);
}
 
void AArch64AsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI) {
  emitSled(MI, SledKind::TAIL_CALL);
}
 
void AArch64AsmPrinter::emitSled(const MachineInstr &MI, SledKind Kind) {
  static const int8_t NoopsInSledCount = 7;
  // We want to emit the following pattern:
  //
  // .Lxray_sled_N:
  //   ALIGN
  //   B #32
  //   ; 7 NOP instructions (28 bytes)
  // .tmpN
  //
  // We need the 28 bytes (7 instructions) because at runtime, we'd be patching
  // over the full 32 bytes (8 instructions) with the following pattern:
  //
  //   STP X0, X30, [SP, #-16]! ; push X0 and the link register to the stack
  //   LDR W17, #12 ; W17 := function ID
  //   LDR X16,#12 ; X16 := addr of __xray_FunctionEntry or __xray_FunctionExit
  //   BLR X16 ; call the tracing trampoline
  //   ;DATA: 32 bits of function ID
  //   ;DATA: lower 32 bits of the address of the trampoline
  //   ;DATA: higher 32 bits of the address of the trampoline
  //   LDP X0, X30, [SP], #16 ; pop X0 and the link register from the stack
  //
  OutStreamer->emitCodeAlignment(Align(4), &getSubtargetInfo());
  auto CurSled = OutContext.createTempSymbol("xray_sled_", true);
  OutStreamer->emitLabel(CurSled);
  auto Target = OutContext.createTempSymbol();
 
  // Emit "B #32" instruction, which jumps over the next 28 bytes.
  // The operand has to be the number of 4-byte instructions to jump over,
  // including the current instruction.
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::B).addImm(8));
 
  for (int8_t I = 0; I < NoopsInSledCount; I++)
    EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::NOP));
 
  OutStreamer->emitLabel(Target);
  recordSled(CurSled, MI, Kind, 2);
}
 
void AArch64AsmPrinter::emitAttributes(unsigned Flags,
                                       uint64_t PAuthABIPlatform,
                                       uint64_t PAuthABIVersion,
                                       AArch64TargetStreamer *TS) {
 
  PAuthABIPlatform = (uint64_t(-1) == PAuthABIPlatform) ? 0 : PAuthABIPlatform;
  PAuthABIVersion = (uint64_t(-1) == PAuthABIVersion) ? 0 : PAuthABIVersion;
 
  if (PAuthABIPlatform || PAuthABIVersion) {
    TS->emitAttributesSubsection(
        AArch64BuildAttributes::getVendorName(
            AArch64BuildAttributes::AEABI_PAUTHABI),
        AArch64BuildAttributes::SubsectionOptional::REQUIRED,
        AArch64BuildAttributes::SubsectionType::ULEB128);
    TS->emitAttribute(AArch64BuildAttributes::getVendorName(
                          AArch64BuildAttributes::AEABI_PAUTHABI),
                      AArch64BuildAttributes::TAG_PAUTH_PLATFORM,
                      PAuthABIPlatform, "");
    TS->emitAttribute(AArch64BuildAttributes::getVendorName(
                          AArch64BuildAttributes::AEABI_PAUTHABI),
                      AArch64BuildAttributes::TAG_PAUTH_SCHEMA, PAuthABIVersion,
                      "");
  }
 
  unsigned BTIValue =
      (Flags & AArch64BuildAttributes::Feature_BTI_Flag) ? 1 : 0;
  unsigned PACValue =
      (Flags & AArch64BuildAttributes::Feature_PAC_Flag) ? 1 : 0;
  unsigned GCSValue =
      (Flags & AArch64BuildAttributes::Feature_GCS_Flag) ? 1 : 0;
 
  if (BTIValue || PACValue || GCSValue) {
    TS->emitAttributesSubsection(
        AArch64BuildAttributes::getVendorName(
            AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
        AArch64BuildAttributes::SubsectionOptional::OPTIONAL,
        AArch64BuildAttributes::SubsectionType::ULEB128);
    TS->emitAttribute(AArch64BuildAttributes::getVendorName(
                          AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
                      AArch64BuildAttributes::TAG_FEATURE_BTI, BTIValue, "");
    TS->emitAttribute(AArch64BuildAttributes::getVendorName(
                          AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
                      AArch64BuildAttributes::TAG_FEATURE_PAC, PACValue, "");
    TS->emitAttribute(AArch64BuildAttributes::getVendorName(
                          AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
                      AArch64BuildAttributes::TAG_FEATURE_GCS, GCSValue, "");
  }
}
 
// Emit the following code for Intrinsic::{xray_customevent,xray_typedevent}
// (built-in functions __xray_customevent/__xray_typedevent).
//
// .Lxray_event_sled_N:
//   b 1f
//   save x0 and x1 (and also x2 for TYPED_EVENT_CALL)
//   set up x0 and x1 (and also x2 for TYPED_EVENT_CALL)
//   bl __xray_CustomEvent or __xray_TypedEvent
//   restore x0 and x1 (and also x2 for TYPED_EVENT_CALL)
// 1:
//
// There are 6 instructions for EVENT_CALL and 9 for TYPED_EVENT_CALL.
//
// Then record a sled of kind CUSTOM_EVENT or TYPED_EVENT.
// After patching, b .+N will become a nop.
void AArch64AsmPrinter::LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI,
                                                  bool Typed) {
  auto &O = *OutStreamer;
  MCSymbol *CurSled = OutContext.createTempSymbol("xray_sled_", true);
  O.emitLabel(CurSled);
  bool MachO = TM.getTargetTriple().isOSBinFormatMachO();
  auto *Sym = MCSymbolRefExpr::create(
      OutContext.getOrCreateSymbol(
          Twine(MachO ? "_" : "") +
          (Typed ? "__xray_TypedEvent" : "__xray_CustomEvent")),
      OutContext);
  if (Typed) {
    O.AddComment("Begin XRay typed event");
    EmitToStreamer(O, MCInstBuilder(AArch64::B).addImm(9));
    EmitToStreamer(O, MCInstBuilder(AArch64::STPXpre)
                          .addReg(AArch64::SP)
                          .addReg(AArch64::X0)
                          .addReg(AArch64::X1)
                          .addReg(AArch64::SP)
                          .addImm(-4));
    EmitToStreamer(O, MCInstBuilder(AArch64::STRXui)
                          .addReg(AArch64::X2)
                          .addReg(AArch64::SP)
                          .addImm(2));
    emitMovXReg(AArch64::X0, MI.getOperand(0).getReg());
    emitMovXReg(AArch64::X1, MI.getOperand(1).getReg());
    emitMovXReg(AArch64::X2, MI.getOperand(2).getReg());
    EmitToStreamer(O, MCInstBuilder(AArch64::BL).addExpr(Sym));
    EmitToStreamer(O, MCInstBuilder(AArch64::LDRXui)
                          .addReg(AArch64::X2)
                          .addReg(AArch64::SP)
                          .addImm(2));
    O.AddComment("End XRay typed event");
    EmitToStreamer(O, MCInstBuilder(AArch64::LDPXpost)
                          .addReg(AArch64::SP)
                          .addReg(AArch64::X0)
                          .addReg(AArch64::X1)
                          .addReg(AArch64::SP)
                          .addImm(4));
 
    recordSled(CurSled, MI, SledKind::TYPED_EVENT, 2);
  } else {
    O.AddComment("Begin XRay custom event");
    EmitToStreamer(O, MCInstBuilder(AArch64::B).addImm(6));
    EmitToStreamer(O, MCInstBuilder(AArch64::STPXpre)
                          .addReg(AArch64::SP)
                          .addReg(AArch64::X0)
                          .addReg(AArch64::X1)
                          .addReg(AArch64::SP)
                          .addImm(-2));
    emitMovXReg(AArch64::X0, MI.getOperand(0).getReg());
    emitMovXReg(AArch64::X1, MI.getOperand(1).getReg());
    EmitToStreamer(O, MCInstBuilder(AArch64::BL).addExpr(Sym));
    O.AddComment("End XRay custom event");
    EmitToStreamer(O, MCInstBuilder(AArch64::LDPXpost)
                          .addReg(AArch64::SP)
                          .addReg(AArch64::X0)
                          .addReg(AArch64::X1)
                          .addReg(AArch64::SP)
                          .addImm(2));
 
    recordSled(CurSled, MI, SledKind::CUSTOM_EVENT, 2);
  }
}
 
void AArch64AsmPrinter::LowerKCFI_CHECK(const MachineInstr &MI) {
  Register AddrReg = MI.getOperand(0).getReg();
  assert(std::next(MI.getIterator())->isCall() &&
         "KCFI_CHECK not followed by a call instruction");
  assert(std::next(MI.getIterator())->getOperand(0).getReg() == AddrReg &&
         "KCFI_CHECK call target doesn't match call operand");
 
  // Default to using the intra-procedure-call temporary registers for
  // comparing the hashes.
  unsigned ScratchRegs[] = {AArch64::W16, AArch64::W17};
  if (AddrReg == AArch64::XZR) {
    // Checking XZR makes no sense. Instead of emitting a load, zero
    // ScratchRegs[0] and use it for the ESR AddrIndex below.
    AddrReg = getXRegFromWReg(ScratchRegs[0]);
    emitMovXReg(AddrReg, AArch64::XZR);
  } else {
    // If one of the scratch registers is used for the call target (e.g.
    // with AArch64::TCRETURNriBTI), we can clobber another caller-saved
    // temporary register instead (in this case, AArch64::W9) as the check
    // is immediately followed by the call instruction.
    for (auto &Reg : ScratchRegs) {
      if (Reg == getWRegFromXReg(AddrReg)) {
        Reg = AArch64::W9;
        break;
      }
    }
    assert(ScratchRegs[0] != AddrReg && ScratchRegs[1] != AddrReg &&
           "Invalid scratch registers for KCFI_CHECK");
 
    // Adjust the offset for patchable-function-prefix. This assumes that
    // patchable-function-prefix is the same for all functions.
    int64_t PrefixNops = 0;
    (void)MI.getMF()
        ->getFunction()
        .getFnAttribute("patchable-function-prefix")
        .getValueAsString()
        .getAsInteger(10, PrefixNops);
 
    // Load the target function type hash.
    EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDURWi)
                                     .addReg(ScratchRegs[0])
                                     .addReg(AddrReg)
                                     .addImm(-(PrefixNops * 4 + 4)));
  }
 
  // Load the expected type hash.
  const int64_t Type = MI.getOperand(1).getImm();
  emitMOVK(ScratchRegs[1], Type & 0xFFFF, 0);
  emitMOVK(ScratchRegs[1], (Type >> 16) & 0xFFFF, 16);
 
  // Compare the hashes and trap if there's a mismatch.
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSWrs)
                                   .addReg(AArch64::WZR)
                                   .addReg(ScratchRegs[0])
                                   .addReg(ScratchRegs[1])
                                   .addImm(0));
 
  MCSymbol *Pass = OutContext.createTempSymbol();
  EmitToStreamer(*OutStreamer,
                 MCInstBuilder(AArch64::Bcc)
                     .addImm(AArch64CC::EQ)
                     .addExpr(MCSymbolRefExpr::create(Pass, OutContext)));
 
  // The base ESR is 0x8000 and the register information is encoded in bits
  // 0-9 as follows:
  // - 0-4: n, where the register Xn contains the target address
  // - 5-9: m, where the register Wm contains the expected type hash
  // Where n, m are in [0, 30].
  unsigned TypeIndex = ScratchRegs[1] - AArch64::W0;
  unsigned AddrIndex;
  switch (AddrReg) {
  default:
    AddrIndex = AddrReg - AArch64::X0;
    break;
  case AArch64::FP:
    AddrIndex = 29;
    break;
  case AArch64::LR:
    AddrIndex = 30;
    break;
  }
 
  assert(AddrIndex < 31 && TypeIndex < 31);
 
  unsigned ESR = 0x8000 | ((TypeIndex & 31) << 5) | (AddrIndex & 31);
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::BRK).addImm(ESR));
  OutStreamer->emitLabel(Pass);
}
 
void AArch64AsmPrinter::LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI) {
  Register Reg = MI.getOperand(0).getReg();
 
  // The HWASan pass won't emit a CHECK_MEMACCESS intrinsic with a pointer
  // statically known to be zero. However, conceivably, the HWASan pass may
  // encounter a "cannot currently statically prove to be null" pointer (and is
  // therefore unable to omit the intrinsic) that later optimization passes
  // convert into a statically known-null pointer.
  if (Reg == AArch64::XZR)
    return;
 
  bool IsShort =
      ((MI.getOpcode() == AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES) ||
       (MI.getOpcode() ==
        AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW));
  uint32_t AccessInfo = MI.getOperand(1).getImm();
  bool IsFixedShadow =
      ((MI.getOpcode() == AArch64::HWASAN_CHECK_MEMACCESS_FIXEDSHADOW) ||
       (MI.getOpcode() ==
        AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW));
  uint64_t FixedShadowOffset = IsFixedShadow ? MI.getOperand(2).getImm() : 0;
 
  MCSymbol *&Sym = HwasanMemaccessSymbols[HwasanMemaccessTuple(
      Reg, IsShort, AccessInfo, IsFixedShadow, FixedShadowOffset)];
  if (!Sym) {
    // FIXME: Make this work on non-ELF.
    if (!TM.getTargetTriple().isOSBinFormatELF())
      report_fatal_error("llvm.hwasan.check.memaccess only supported on ELF");
 
    std::string SymName = "__hwasan_check_x" + utostr(Reg - AArch64::X0) + "_" +
                          utostr(AccessInfo);
    if (IsFixedShadow)
      SymName += "_fixed_" + utostr(FixedShadowOffset);
    if (IsShort)
      SymName += "_short_v2";
    Sym = OutContext.getOrCreateSymbol(SymName);
  }
 
  EmitToStreamer(*OutStreamer,
                 MCInstBuilder(AArch64::BL)
                     .addExpr(MCSymbolRefExpr::create(Sym, OutContext)));
}
 
void AArch64AsmPrinter::emitHwasanMemaccessSymbols(Module &M) {
  if (HwasanMemaccessSymbols.empty())
    return;
 
  const Triple &TT = TM.getTargetTriple();
  assert(TT.isOSBinFormatELF());
  // AArch64Subtarget is huge, so heap allocate it so we don't run out of stack
  // space.
  auto STI = std::make_unique<AArch64Subtarget>(
      TT, TM.getTargetCPU(), TM.getTargetCPU(), TM.getTargetFeatureString(), TM,
      true);
  this->STI = STI.get();
 
  MCSymbol *HwasanTagMismatchV1Sym =
      OutContext.getOrCreateSymbol("__hwasan_tag_mismatch");
  MCSymbol *HwasanTagMismatchV2Sym =
      OutContext.getOrCreateSymbol("__hwasan_tag_mismatch_v2");
 
  const MCSymbolRefExpr *HwasanTagMismatchV1Ref =
      MCSymbolRefExpr::create(HwasanTagMismatchV1Sym, OutContext);
  const MCSymbolRefExpr *HwasanTagMismatchV2Ref =
      MCSymbolRefExpr::create(HwasanTagMismatchV2Sym, OutContext);
 
  for (auto &P : HwasanMemaccessSymbols) {
    unsigned Reg = std::get<0>(P.first);
    bool IsShort = std::get<1>(P.first);
    uint32_t AccessInfo = std::get<2>(P.first);
    bool IsFixedShadow = std::get<3>(P.first);
    uint64_t FixedShadowOffset = std::get<4>(P.first);
    const MCSymbolRefExpr *HwasanTagMismatchRef =
        IsShort ? HwasanTagMismatchV2Ref : HwasanTagMismatchV1Ref;
    MCSymbol *Sym = P.second;
 
    bool HasMatchAllTag =
        (AccessInfo >> HWASanAccessInfo::HasMatchAllShift) & 1;
    uint8_t MatchAllTag =
        (AccessInfo >> HWASanAccessInfo::MatchAllShift) & 0xff;
    unsigned Size =
        1 << ((AccessInfo >> HWASanAccessInfo::AccessSizeShift) & 0xf);
    bool CompileKernel =
        (AccessInfo >> HWASanAccessInfo::CompileKernelShift) & 1;
 
    OutStreamer->switchSection(OutContext.getELFSection(
        ".text.hot", ELF::SHT_PROGBITS,
        ELF::SHF_EXECINSTR | ELF::SHF_ALLOC | ELF::SHF_GROUP, 0, Sym->getName(),
        /*IsComdat=*/true));
 
    OutStreamer->emitSymbolAttribute(Sym, MCSA_ELF_TypeFunction);
    OutStreamer->emitSymbolAttribute(Sym, MCSA_Weak);
    OutStreamer->emitSymbolAttribute(Sym, MCSA_Hidden);
    OutStreamer->emitLabel(Sym);
 
    EmitToStreamer(MCInstBuilder(AArch64::SBFMXri)
                       .addReg(AArch64::X16)
                       .addReg(Reg)
                       .addImm(4)
                       .addImm(55));
 
    if (IsFixedShadow) {
      // Aarch64 makes it difficult to embed large constants in the code.
      // Fortuitously, kShadowBaseAlignment == 32, so we use the 32-bit
      // left-shift option in the MOV instruction. Combined with the 16-bit
      // immediate, this is enough to represent any offset up to 2**48.
      emitMOVZ(AArch64::X17, FixedShadowOffset >> 32, 32);
      EmitToStreamer(MCInstBuilder(AArch64::LDRBBroX)
                         .addReg(AArch64::W16)
                         .addReg(AArch64::X17)
                         .addReg(AArch64::X16)
                         .addImm(0)
                         .addImm(0));
    } else {
      EmitToStreamer(MCInstBuilder(AArch64::LDRBBroX)
                         .addReg(AArch64::W16)
                         .addReg(IsShort ? AArch64::X20 : AArch64::X9)
                         .addReg(AArch64::X16)
                         .addImm(0)
                         .addImm(0));
    }
 
    EmitToStreamer(MCInstBuilder(AArch64::SUBSXrs)
                       .addReg(AArch64::XZR)
                       .addReg(AArch64::X16)
                       .addReg(Reg)
                       .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)));
    MCSymbol *HandleMismatchOrPartialSym = OutContext.createTempSymbol();
    EmitToStreamer(MCInstBuilder(AArch64::Bcc)
                       .addImm(AArch64CC::NE)
                       .addExpr(MCSymbolRefExpr::create(
                           HandleMismatchOrPartialSym, OutContext)));
    MCSymbol *ReturnSym = OutContext.createTempSymbol();
    OutStreamer->emitLabel(ReturnSym);
    EmitToStreamer(MCInstBuilder(AArch64::RET).addReg(AArch64::LR));
    OutStreamer->emitLabel(HandleMismatchOrPartialSym);
 
    if (HasMatchAllTag) {
      EmitToStreamer(MCInstBuilder(AArch64::UBFMXri)
                         .addReg(AArch64::X17)
                         .addReg(Reg)
                         .addImm(56)
                         .addImm(63));
      EmitToStreamer(MCInstBuilder(AArch64::SUBSXri)
                         .addReg(AArch64::XZR)
                         .addReg(AArch64::X17)
                         .addImm(MatchAllTag)
                         .addImm(0));
      EmitToStreamer(
          MCInstBuilder(AArch64::Bcc)
              .addImm(AArch64CC::EQ)
              .addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)));
    }
 
    if (IsShort) {
      EmitToStreamer(MCInstBuilder(AArch64::SUBSWri)
                         .addReg(AArch64::WZR)
                         .addReg(AArch64::W16)
                         .addImm(15)
                         .addImm(0));
      MCSymbol *HandleMismatchSym = OutContext.createTempSymbol();
      EmitToStreamer(
          MCInstBuilder(AArch64::Bcc)
              .addImm(AArch64CC::HI)
              .addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)));
 
      EmitToStreamer(MCInstBuilder(AArch64::ANDXri)
                         .addReg(AArch64::X17)
                         .addReg(Reg)
                         .addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)));
      if (Size != 1)
        EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                           .addReg(AArch64::X17)
                           .addReg(AArch64::X17)
                           .addImm(Size - 1)
                           .addImm(0));
      EmitToStreamer(MCInstBuilder(AArch64::SUBSWrs)
                         .addReg(AArch64::WZR)
                         .addReg(AArch64::W16)
                         .addReg(AArch64::W17)
                         .addImm(0));
      EmitToStreamer(
          MCInstBuilder(AArch64::Bcc)
              .addImm(AArch64CC::LS)
              .addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)));
 
      EmitToStreamer(MCInstBuilder(AArch64::ORRXri)
                         .addReg(AArch64::X16)
                         .addReg(Reg)
                         .addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)));
      EmitToStreamer(MCInstBuilder(AArch64::LDRBBui)
                         .addReg(AArch64::W16)
                         .addReg(AArch64::X16)
                         .addImm(0));
      EmitToStreamer(
          MCInstBuilder(AArch64::SUBSXrs)
              .addReg(AArch64::XZR)
              .addReg(AArch64::X16)
              .addReg(Reg)
              .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)));
      EmitToStreamer(
          MCInstBuilder(AArch64::Bcc)
              .addImm(AArch64CC::EQ)
              .addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)));
 
      OutStreamer->emitLabel(HandleMismatchSym);
    }
 
    EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
                       .addReg(AArch64::SP)
                       .addReg(AArch64::X0)
                       .addReg(AArch64::X1)
                       .addReg(AArch64::SP)
                       .addImm(-32));
    EmitToStreamer(MCInstBuilder(AArch64::STPXi)
                       .addReg(AArch64::FP)
                       .addReg(AArch64::LR)
                       .addReg(AArch64::SP)
                       .addImm(29));
 
    if (Reg != AArch64::X0)
      emitMovXReg(AArch64::X0, Reg);
    emitMOVZ(AArch64::X1, AccessInfo & HWASanAccessInfo::RuntimeMask, 0);
 
    if (CompileKernel) {
      // The Linux kernel's dynamic loader doesn't support GOT relative
      // relocations, but it doesn't support late binding either, so just call
      // the function directly.
      EmitToStreamer(MCInstBuilder(AArch64::B).addExpr(HwasanTagMismatchRef));
    } else {
      // Intentionally load the GOT entry and branch to it, rather than possibly
      // late binding the function, which may clobber the registers before we
      // have a chance to save them.
      EmitToStreamer(MCInstBuilder(AArch64::ADRP)
                         .addReg(AArch64::X16)
                         .addExpr(MCSpecifierExpr::create(HwasanTagMismatchRef,
                                                          AArch64::S_GOT_PAGE,
                                                          OutContext)));
      EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                         .addReg(AArch64::X16)
                         .addReg(AArch64::X16)
                         .addExpr(MCSpecifierExpr::create(HwasanTagMismatchRef,
                                                          AArch64::S_GOT_LO12,
                                                          OutContext)));
      EmitToStreamer(MCInstBuilder(AArch64::BR).addReg(AArch64::X16));
    }
  }
  this->STI = nullptr;
}
 
static void emitAuthenticatedPointer(MCStreamer &OutStreamer,
                                     MCSymbol *StubLabel,
                                     const MCExpr *StubAuthPtrRef) {
  // sym$auth_ptr$key$disc:
  OutStreamer.emitLabel(StubLabel);
  OutStreamer.emitValue(StubAuthPtrRef, /*size=*/8);
}
 
void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
  emitHwasanMemaccessSymbols(M);
 
  const Triple &TT = TM.getTargetTriple();
  if (TT.isOSBinFormatMachO()) {
    // Output authenticated pointers as indirect symbols, if we have any.
    MachineModuleInfoMachO &MMIMacho =
        MMI->getObjFileInfo<MachineModuleInfoMachO>();
 
    auto Stubs = MMIMacho.getAuthGVStubList();
 
    if (!Stubs.empty()) {
      // Switch to the "__auth_ptr" section.
      OutStreamer->switchSection(
          OutContext.getMachOSection("__DATA", "__auth_ptr", MachO::S_REGULAR,
                                     SectionKind::getMetadata()));
      emitAlignment(Align(8));
 
      for (const auto &Stub : Stubs)
        emitAuthenticatedPointer(*OutStreamer, Stub.first, Stub.second);
 
      OutStreamer->addBlankLine();
    }
 
    // Funny Darwin hack: This flag tells the linker that no global symbols
    // contain code that falls through to other global symbols (e.g. the obvious
    // implementation of multiple entry points).  If this doesn't occur, the
    // linker can safely perform dead code stripping.  Since LLVM never
    // generates code that does this, it is always safe to set.
    OutStreamer->emitSubsectionsViaSymbols();
  }
 
  if (TT.isOSBinFormatELF()) {
    // Output authenticated pointers as indirect symbols, if we have any.
    MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
 
    auto Stubs = MMIELF.getAuthGVStubList();
 
    if (!Stubs.empty()) {
      const TargetLoweringObjectFile &TLOF = getObjFileLowering();
      OutStreamer->switchSection(TLOF.getDataSection());
      emitAlignment(Align(8));
 
      for (const auto &Stub : Stubs)
        emitAuthenticatedPointer(*OutStreamer, Stub.first, Stub.second);
 
      OutStreamer->addBlankLine();
    }
 
    // With signed ELF GOT enabled, the linker looks at the symbol type to
    // choose between keys IA (for STT_FUNC) and DA (for other types). Symbols
    // for functions not defined in the module have STT_NOTYPE type by default.
    // This makes linker to emit signing schema with DA key (instead of IA) for
    // corresponding R_AARCH64_AUTH_GLOB_DAT dynamic reloc. To avoid that, force
    // all function symbols used in the module to have STT_FUNC type. See
    // https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#default-signing-schema
    const auto *PtrAuthELFGOTFlag = mdconst::extract_or_null<ConstantInt>(
        M.getModuleFlag("ptrauth-elf-got"));
    if (PtrAuthELFGOTFlag && PtrAuthELFGOTFlag->getZExtValue() == 1)
      for (const GlobalValue &GV : M.global_values())
        if (!GV.use_empty() && isa<Function>(GV) &&
            !GV.getName().starts_with("llvm."))
          OutStreamer->emitSymbolAttribute(getSymbol(&GV),
                                           MCSA_ELF_TypeFunction);
  }
 
  // Emit stack and fault map information.
  FM.serializeToFaultMapSection();
 
  // If import call optimization is enabled, emit the appropriate section.
  // We do this whether or not we recorded any import calls.
  if (EnableImportCallOptimization && TT.isOSBinFormatCOFF()) {
    OutStreamer->switchSection(getObjFileLowering().getImportCallSection());
 
    // Section always starts with some magic.
    constexpr char ImpCallMagic[12] = "Imp_Call_V1";
    OutStreamer->emitBytes(StringRef{ImpCallMagic, sizeof(ImpCallMagic)});
 
    // Layout of this section is:
    // Per section that contains calls to imported functions:
    //  uint32_t SectionSize: Size in bytes for information in this section.
    //  uint32_t Section Number
    //  Per call to imported function in section:
    //    uint32_t Kind: the kind of imported function.
    //    uint32_t BranchOffset: the offset of the branch instruction in its
    //                            parent section.
    //    uint32_t TargetSymbolId: the symbol id of the called function.
    for (auto &[Section, CallsToImportedFuncs] :
         SectionToImportedFunctionCalls) {
      unsigned SectionSize =
          sizeof(uint32_t) * (2 + 3 * CallsToImportedFuncs.size());
      OutStreamer->emitInt32(SectionSize);
      OutStreamer->emitCOFFSecNumber(Section->getBeginSymbol());
      for (auto &[CallsiteSymbol, CalledSymbol] : CallsToImportedFuncs) {
        // Kind is always IMAGE_REL_ARM64_DYNAMIC_IMPORT_CALL (0x13).
        OutStreamer->emitInt32(0x13);
        OutStreamer->emitCOFFSecOffset(CallsiteSymbol);
        OutStreamer->emitCOFFSymbolIndex(CalledSymbol);
      }
    }
  }
}
 
void AArch64AsmPrinter::emitLOHs() {
  SmallVector<MCSymbol *, 3> MCArgs;
 
  for (const auto &D : AArch64FI->getLOHContainer()) {
    for (const MachineInstr *MI : D.getArgs()) {
      MInstToMCSymbol::iterator LabelIt = LOHInstToLabel.find(MI);
      assert(LabelIt != LOHInstToLabel.end() &&
             "Label hasn't been inserted for LOH related instruction");
      MCArgs.push_back(LabelIt->second);
    }
    OutStreamer->emitLOHDirective(D.getKind(), MCArgs);
    MCArgs.clear();
  }
}
 
void AArch64AsmPrinter::emitFunctionBodyEnd() {
  if (!AArch64FI->getLOHRelated().empty())
    emitLOHs();
}
 
/// GetCPISymbol - Return the symbol for the specified constant pool entry.
MCSymbol *AArch64AsmPrinter::GetCPISymbol(unsigned CPID) const {
  // Darwin uses a linker-private symbol name for constant-pools (to
  // avoid addends on the relocation?), ELF has no such concept and
  // uses a normal private symbol.
  if (!getDataLayout().getLinkerPrivateGlobalPrefix().empty())
    return OutContext.getOrCreateSymbol(
        Twine(getDataLayout().getLinkerPrivateGlobalPrefix()) + "CPI" +
        Twine(getFunctionNumber()) + "_" + Twine(CPID));
 
  return AsmPrinter::GetCPISymbol(CPID);
}
 
void AArch64AsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNum,
                                     raw_ostream &O) {
  const MachineOperand &MO = MI->getOperand(OpNum);
  switch (MO.getType()) {
  default:
    llvm_unreachable("<unknown operand type>");
  case MachineOperand::MO_Register: {
    Register Reg = MO.getReg();
    assert(Reg.isPhysical());
    assert(!MO.getSubReg() && "Subregs should be eliminated!");
    O << AArch64InstPrinter::getRegisterName(Reg);
    break;
  }
  case MachineOperand::MO_Immediate: {
    O << MO.getImm();
    break;
  }
  case MachineOperand::MO_GlobalAddress: {
    PrintSymbolOperand(MO, O);
    break;
  }
  case MachineOperand::MO_BlockAddress: {
    MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress());
    Sym->print(O, MAI);
    break;
  }
  }
}
 
bool AArch64AsmPrinter::printAsmMRegister(const MachineOperand &MO, char Mode,
                                          raw_ostream &O) {
  Register Reg = MO.getReg();
  switch (Mode) {
  default:
    return true; // Unknown mode.
  case 'w':
    Reg = getWRegFromXReg(Reg);
    break;
  case 'x':
    Reg = getXRegFromWReg(Reg);
    break;
  case 't':
    Reg = getXRegFromXRegTuple(Reg);
    break;
  }
 
  O << AArch64InstPrinter::getRegisterName(Reg);
  return false;
}
 
// Prints the register in MO using class RC using the offset in the
// new register class. This should not be used for cross class
// printing.
bool AArch64AsmPrinter::printAsmRegInClass(const MachineOperand &MO,
                                           const TargetRegisterClass *RC,
                                           unsigned AltName, raw_ostream &O) {
  assert(MO.isReg() && "Should only get here with a register!");
  const TargetRegisterInfo *RI = STI->getRegisterInfo();
  Register Reg = MO.getReg();
  MCRegister RegToPrint = RC->getRegister(RI->getEncodingValue(Reg));
  if (!RI->regsOverlap(RegToPrint, Reg))
    return true;
  O << AArch64InstPrinter::getRegisterName(RegToPrint, AltName);
  return false;
}
 
bool AArch64AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
                                        const char *ExtraCode, raw_ostream &O) {
  const MachineOperand &MO = MI->getOperand(OpNum);
 
  // First try the generic code, which knows about modifiers like 'c' and 'n'.
  if (!AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O))
    return false;
 
  // Does this asm operand have a single letter operand modifier?
  if (ExtraCode && ExtraCode[0]) {
    if (ExtraCode[1] != 0)
      return true; // Unknown modifier.
 
    switch (ExtraCode[0]) {
    default:
      return true; // Unknown modifier.
    case 'w':      // Print W register
    case 'x':      // Print X register
      if (MO.isReg())
        return printAsmMRegister(MO, ExtraCode[0], O);
      if (MO.isImm() && MO.getImm() == 0) {
        unsigned Reg = ExtraCode[0] == 'w' ? AArch64::WZR : AArch64::XZR;
        O << AArch64InstPrinter::getRegisterName(Reg);
        return false;
      }
      printOperand(MI, OpNum, O);
      return false;
    case 'b': // Print B register.
    case 'h': // Print H register.
    case 's': // Print S register.
    case 'd': // Print D register.
    case 'q': // Print Q register.
    case 'z': // Print Z register.
      if (MO.isReg()) {
        const TargetRegisterClass *RC;
        switch (ExtraCode[0]) {
        case 'b':
          RC = &AArch64::FPR8RegClass;
          break;
        case 'h':
          RC = &AArch64::FPR16RegClass;
          break;
        case 's':
          RC = &AArch64::FPR32RegClass;
          break;
        case 'd':
          RC = &AArch64::FPR64RegClass;
          break;
        case 'q':
          RC = &AArch64::FPR128RegClass;
          break;
        case 'z':
          RC = &AArch64::ZPRRegClass;
          break;
        default:
          return true;
        }
        return printAsmRegInClass(MO, RC, AArch64::NoRegAltName, O);
      }
      printOperand(MI, OpNum, O);
      return false;
    }
  }
 
  // According to ARM, we should emit x and v registers unless we have a
  // modifier.
  if (MO.isReg()) {
    Register Reg = MO.getReg();
 
    // If this is a w or x register, print an x register.
    if (AArch64::GPR32allRegClass.contains(Reg) ||
        AArch64::GPR64allRegClass.contains(Reg))
      return printAsmMRegister(MO, 'x', O);
 
    // If this is an x register tuple, print an x register.
    if (AArch64::GPR64x8ClassRegClass.contains(Reg))
      return printAsmMRegister(MO, 't', O);
 
    unsigned AltName = AArch64::NoRegAltName;
    const TargetRegisterClass *RegClass;
    if (AArch64::ZPRRegClass.contains(Reg)) {
      RegClass = &AArch64::ZPRRegClass;
    } else if (AArch64::PPRRegClass.contains(Reg)) {
      RegClass = &AArch64::PPRRegClass;
    } else if (AArch64::PNRRegClass.contains(Reg)) {
      RegClass = &AArch64::PNRRegClass;
    } else {
      RegClass = &AArch64::FPR128RegClass;
      AltName = AArch64::vreg;
    }
 
    // If this is a b, h, s, d, or q register, print it as a v register.
    return printAsmRegInClass(MO, RegClass, AltName, O);
  }
 
  printOperand(MI, OpNum, O);
  return false;
}
 
bool AArch64AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
                                              unsigned OpNum,
                                              const char *ExtraCode,
                                              raw_ostream &O) {
  if (ExtraCode && ExtraCode[0] && ExtraCode[0] != 'a')
    return true; // Unknown modifier.
 
  const MachineOperand &MO = MI->getOperand(OpNum);
  assert(MO.isReg() && "unexpected inline asm memory operand");
  O << "[" << AArch64InstPrinter::getRegisterName(MO.getReg()) << "]";
  return false;
}
 
void AArch64AsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
                                               raw_ostream &OS) {
  unsigned NOps = MI->getNumOperands();
  assert(NOps == 4);
  OS << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
  // cast away const; DIetc do not take const operands for some reason.
  OS << MI->getDebugVariable()->getName();
  OS << " <- ";
  // Frame address.  Currently handles register +- offset only.
  assert(MI->isIndirectDebugValue());
  OS << '[';
  for (unsigned I = 0, E = llvm::size(MI->debug_operands()); I < E; ++I) {
    if (I != 0)
      OS << ", ";
    printOperand(MI, I, OS);
  }
  OS << ']';
  OS << "+";
  printOperand(MI, NOps - 2, OS);
}
 
void AArch64AsmPrinter::emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
                                          ArrayRef<unsigned> JumpTableIndices) {
  // Fast return if there is nothing to emit to avoid creating empty sections.
  if (JumpTableIndices.empty())
    return;
  const TargetLoweringObjectFile &TLOF = getObjFileLowering();
  const auto &F = MF->getFunction();
  ArrayRef<MachineJumpTableEntry> JT = MJTI.getJumpTables();
 
  MCSection *ReadOnlySec = nullptr;
  if (TM.Options.EnableStaticDataPartitioning) {
    ReadOnlySec =
        TLOF.getSectionForJumpTable(F, TM, &JT[JumpTableIndices.front()]);
  } else {
    ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
  }
  OutStreamer->switchSection(ReadOnlySec);
 
  auto AFI = MF->getInfo<AArch64FunctionInfo>();
  for (unsigned JTI : JumpTableIndices) {
    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
 
    // If this jump table was deleted, ignore it.
    if (JTBBs.empty()) continue;
 
    unsigned Size = AFI->getJumpTableEntrySize(JTI);
    emitAlignment(Align(Size));
    OutStreamer->emitLabel(GetJTISymbol(JTI));
 
    const MCSymbol *BaseSym = AArch64FI->getJumpTableEntryPCRelSymbol(JTI);
    const MCExpr *Base = MCSymbolRefExpr::create(BaseSym, OutContext);
 
    for (auto *JTBB : JTBBs) {
      const MCExpr *Value =
          MCSymbolRefExpr::create(JTBB->getSymbol(), OutContext);
 
      // Each entry is:
      //     .byte/.hword (LBB - Lbase)>>2
      // or plain:
      //     .word LBB - Lbase
      Value = MCBinaryExpr::createSub(Value, Base, OutContext);
      if (Size != 4)
        Value = MCBinaryExpr::createLShr(
            Value, MCConstantExpr::create(2, OutContext), OutContext);
 
      OutStreamer->emitValue(Value, Size);
    }
  }
}
 
std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
           codeview::JumpTableEntrySize>
AArch64AsmPrinter::getCodeViewJumpTableInfo(int JTI,
                                            const MachineInstr *BranchInstr,
                                            const MCSymbol *BranchLabel) const {
  const auto AFI = MF->getInfo<AArch64FunctionInfo>();
  const auto Base = AArch64FI->getJumpTableEntryPCRelSymbol(JTI);
  codeview::JumpTableEntrySize EntrySize;
  switch (AFI->getJumpTableEntrySize(JTI)) {
  case 1:
    EntrySize = codeview::JumpTableEntrySize::UInt8ShiftLeft;
    break;
  case 2:
    EntrySize = codeview::JumpTableEntrySize::UInt16ShiftLeft;
    break;
  case 4:
    EntrySize = codeview::JumpTableEntrySize::Int32;
    break;
  default:
    llvm_unreachable("Unexpected jump table entry size");
  }
  return std::make_tuple(Base, 0, BranchLabel, EntrySize);
}
 
void AArch64AsmPrinter::emitFunctionEntryLabel() {
  const Triple &TT = TM.getTargetTriple();
  if (TT.isOSBinFormatELF() &&
      (MF->getFunction().getCallingConv() == CallingConv::AArch64_VectorCall ||
       MF->getFunction().getCallingConv() ==
           CallingConv::AArch64_SVE_VectorCall ||
       MF->getInfo<AArch64FunctionInfo>()->isSVECC())) {
    auto *TS =
        static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
    TS->emitDirectiveVariantPCS(CurrentFnSym);
  }
 
  AsmPrinter::emitFunctionEntryLabel();
 
  if (TT.isWindowsArm64EC() && !MF->getFunction().hasLocalLinkage()) {
    // For ARM64EC targets, a function definition's name is mangled differently
    // from the normal symbol, emit required aliases here.
    auto emitFunctionAlias = [&](MCSymbol *Src, MCSymbol *Dst) {
      OutStreamer->emitSymbolAttribute(Src, MCSA_WeakAntiDep);
      OutStreamer->emitAssignment(
          Src, MCSymbolRefExpr::create(Dst, MMI->getContext()));
    };
 
    auto getSymbolFromMetadata = [&](StringRef Name) {
      MCSymbol *Sym = nullptr;
      if (MDNode *Node = MF->getFunction().getMetadata(Name)) {
        StringRef NameStr = cast<MDString>(Node->getOperand(0))->getString();
        Sym = MMI->getContext().getOrCreateSymbol(NameStr);
      }
      return Sym;
    };
 
    SmallVector<MDNode *> UnmangledNames;
    MF->getFunction().getMetadata("arm64ec_unmangled_name", UnmangledNames);
    for (MDNode *Node : UnmangledNames) {
      StringRef NameStr = cast<MDString>(Node->getOperand(0))->getString();
      MCSymbol *UnmangledSym = MMI->getContext().getOrCreateSymbol(NameStr);
      if (std::optional<std::string> MangledName =
              getArm64ECMangledFunctionName(UnmangledSym->getName())) {
        MCSymbol *ECMangledSym =
            MMI->getContext().getOrCreateSymbol(*MangledName);
        emitFunctionAlias(UnmangledSym, ECMangledSym);
      }
    }
    if (MCSymbol *ECMangledSym =
            getSymbolFromMetadata("arm64ec_ecmangled_name"))
      emitFunctionAlias(ECMangledSym, CurrentFnSym);
  }
}
 
void AArch64AsmPrinter::emitXXStructor(const DataLayout &DL,
                                       const Constant *CV) {
  if (const auto *CPA = dyn_cast<ConstantPtrAuth>(CV))
    if (CPA->hasAddressDiscriminator() &&
        !CPA->hasSpecialAddressDiscriminator(
            ConstantPtrAuth::AddrDiscriminator_CtorsDtors))
      report_fatal_error(
          "unexpected address discrimination value for ctors/dtors entry, only "
          "'ptr inttoptr (i64 1 to ptr)' is allowed");
  // If we have signed pointers in xxstructors list, they'll be lowered to @AUTH
  // MCExpr's via AArch64AsmPrinter::lowerConstantPtrAuth. It does not look at
  // actual address discrimination value and only checks
  // hasAddressDiscriminator(), so it's OK to leave special address
  // discrimination value here.
  AsmPrinter::emitXXStructor(DL, CV);
}
 
void AArch64AsmPrinter::emitGlobalAlias(const Module &M,
                                        const GlobalAlias &GA) {
  if (auto F = dyn_cast_or_null<Function>(GA.getAliasee())) {
    // Global aliases must point to a definition, but unmangled patchable
    // symbols are special and need to point to an undefined symbol with "EXP+"
    // prefix. Such undefined symbol is resolved by the linker by creating
    // x86 thunk that jumps back to the actual EC target.
    if (MDNode *Node = F->getMetadata("arm64ec_exp_name")) {
      StringRef ExpStr = cast<MDString>(Node->getOperand(0))->getString();
      MCSymbol *ExpSym = MMI->getContext().getOrCreateSymbol(ExpStr);
      MCSymbol *Sym = MMI->getContext().getOrCreateSymbol(GA.getName());
 
      OutStreamer->beginCOFFSymbolDef(ExpSym);
      OutStreamer->emitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
      OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
                                      << COFF::SCT_COMPLEX_TYPE_SHIFT);
      OutStreamer->endCOFFSymbolDef();
 
      OutStreamer->beginCOFFSymbolDef(Sym);
      OutStreamer->emitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
      OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
                                      << COFF::SCT_COMPLEX_TYPE_SHIFT);
      OutStreamer->endCOFFSymbolDef();
      OutStreamer->emitSymbolAttribute(Sym, MCSA_Weak);
      OutStreamer->emitAssignment(
          Sym, MCSymbolRefExpr::create(ExpSym, MMI->getContext()));
      return;
    }
  }
  AsmPrinter::emitGlobalAlias(M, GA);
}
 
/// Small jump tables contain an unsigned byte or half, representing the offset
/// from the lowest-addressed possible destination to the desired basic
/// block. Since all instructions are 4-byte aligned, this is further compressed
/// by counting in instructions rather than bytes (i.e. divided by 4). So, to
/// materialize the correct destination we need:
///
///             adr xDest, .LBB0_0
///             ldrb wScratch, [xTable, xEntry]   (with "lsl #1" for ldrh).
///             add xDest, xDest, xScratch (with "lsl #2" for smaller entries)
void AArch64AsmPrinter::LowerJumpTableDest(llvm::MCStreamer &OutStreamer,
                                           const llvm::MachineInstr &MI) {
  Register DestReg = MI.getOperand(0).getReg();
  Register ScratchReg = MI.getOperand(1).getReg();
  Register ScratchRegW =
      STI->getRegisterInfo()->getSubReg(ScratchReg, AArch64::sub_32);
  Register TableReg = MI.getOperand(2).getReg();
  Register EntryReg = MI.getOperand(3).getReg();
  int JTIdx = MI.getOperand(4).getIndex();
  int Size = AArch64FI->getJumpTableEntrySize(JTIdx);
 
  // This has to be first because the compression pass based its reachability
  // calculations on the start of the JumpTableDest instruction.
  auto Label =
      MF->getInfo<AArch64FunctionInfo>()->getJumpTableEntryPCRelSymbol(JTIdx);
 
  // If we don't already have a symbol to use as the base, use the ADR
  // instruction itself.
  if (!Label) {
    Label = MF->getContext().createTempSymbol();
    AArch64FI->setJumpTableEntryInfo(JTIdx, Size, Label);
    OutStreamer.emitLabel(Label);
  }
 
  auto LabelExpr = MCSymbolRefExpr::create(Label, MF->getContext());
  EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::ADR)
                                  .addReg(DestReg)
                                  .addExpr(LabelExpr));
 
  // Load the number of instruction-steps to offset from the label.
  unsigned LdrOpcode;
  switch (Size) {
  case 1: LdrOpcode = AArch64::LDRBBroX; break;
  case 2: LdrOpcode = AArch64::LDRHHroX; break;
  case 4: LdrOpcode = AArch64::LDRSWroX; break;
  default:
    llvm_unreachable("Unknown jump table size");
  }
 
  EmitToStreamer(OutStreamer, MCInstBuilder(LdrOpcode)
                                  .addReg(Size == 4 ? ScratchReg : ScratchRegW)
                                  .addReg(TableReg)
                                  .addReg(EntryReg)
                                  .addImm(0)
                                  .addImm(Size == 1 ? 0 : 1));
 
  // Add to the already materialized base label address, multiplying by 4 if
  // compressed.
  EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::ADDXrs)
                                  .addReg(DestReg)
                                  .addReg(DestReg)
                                  .addReg(ScratchReg)
                                  .addImm(Size == 4 ? 0 : 2));
}
 
void AArch64AsmPrinter::LowerHardenedBRJumpTable(const MachineInstr &MI) {
  const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
  assert(MJTI && "Can't lower jump-table dispatch without JTI");
 
  const std::vector<MachineJumpTableEntry> &JTs = MJTI->getJumpTables();
  assert(!JTs.empty() && "Invalid JT index for jump-table dispatch");
 
  // Emit:
  //     mov x17, #<size of table>     ; depending on table size, with MOVKs
  //     cmp x16, x17                  ; or #imm if table size fits in 12-bit
  //     csel x16, x16, xzr, ls        ; check for index overflow
  //
  //     adrp x17, Ltable@PAGE         ; materialize table address
  //     add x17, Ltable@PAGEOFF
  //     ldrsw x16, [x17, x16, lsl #2] ; load table entry
  //
  //   Lanchor:
  //     adr x17, Lanchor              ; compute target address
  //     add x16, x17, x16
  //     br x16                        ; branch to target
 
  MachineOperand JTOp = MI.getOperand(0);
 
  unsigned JTI = JTOp.getIndex();
  assert(!AArch64FI->getJumpTableEntryPCRelSymbol(JTI) &&
         "unsupported compressed jump table");
 
  const uint64_t NumTableEntries = JTs[JTI].MBBs.size();
 
  // cmp only supports a 12-bit immediate.  If we need more, materialize the
  // immediate, using x17 as a scratch register.
  uint64_t MaxTableEntry = NumTableEntries - 1;
  if (isUInt<12>(MaxTableEntry)) {
    EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSXri)
                                     .addReg(AArch64::XZR)
                                     .addReg(AArch64::X16)
                                     .addImm(MaxTableEntry)
                                     .addImm(0));
  } else {
    emitMOVZ(AArch64::X17, static_cast<uint16_t>(MaxTableEntry), 0);
    // It's sad that we have to manually materialize instructions, but we can't
    // trivially reuse the main pseudo expansion logic.
    // A MOVK sequence is easy enough to generate and handles the general case.
    for (int Offset = 16; Offset < 64; Offset += 16) {
      if ((MaxTableEntry >> Offset) == 0)
        break;
      emitMOVK(AArch64::X17, static_cast<uint16_t>(MaxTableEntry >> Offset),
               Offset);
    }
    EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSXrs)
                                     .addReg(AArch64::XZR)
                                     .addReg(AArch64::X16)
                                     .addReg(AArch64::X17)
                                     .addImm(0));
  }
 
  // This picks entry #0 on failure.
  // We might want to trap instead.
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::CSELXr)
                                   .addReg(AArch64::X16)
                                   .addReg(AArch64::X16)
                                   .addReg(AArch64::XZR)
                                   .addImm(AArch64CC::LS));
 
  // Prepare the @PAGE/@PAGEOFF low/high operands.
  MachineOperand JTMOHi(JTOp), JTMOLo(JTOp);
  MCOperand JTMCHi, JTMCLo;
 
  JTMOHi.setTargetFlags(AArch64II::MO_PAGE);
  JTMOLo.setTargetFlags(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
 
  MCInstLowering.lowerOperand(JTMOHi, JTMCHi);
  MCInstLowering.lowerOperand(JTMOLo, JTMCLo);
 
  EmitToStreamer(
      *OutStreamer,
      MCInstBuilder(AArch64::ADRP).addReg(AArch64::X17).addOperand(JTMCHi));
 
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXri)
                                   .addReg(AArch64::X17)
                                   .addReg(AArch64::X17)
                                   .addOperand(JTMCLo)
                                   .addImm(0));
 
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRSWroX)
                                   .addReg(AArch64::X16)
                                   .addReg(AArch64::X17)
                                   .addReg(AArch64::X16)
                                   .addImm(0)
                                   .addImm(1));
 
  MCSymbol *AdrLabel = MF->getContext().createTempSymbol();
  const auto *AdrLabelE = MCSymbolRefExpr::create(AdrLabel, MF->getContext());
  AArch64FI->setJumpTableEntryInfo(JTI, 4, AdrLabel);
 
  OutStreamer->emitLabel(AdrLabel);
  EmitToStreamer(
      *OutStreamer,
      MCInstBuilder(AArch64::ADR).addReg(AArch64::X17).addExpr(AdrLabelE));
 
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXrs)
                                   .addReg(AArch64::X16)
                                   .addReg(AArch64::X17)
                                   .addReg(AArch64::X16)
                                   .addImm(0));
 
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::BR).addReg(AArch64::X16));
}
 
void AArch64AsmPrinter::LowerMOPS(llvm::MCStreamer &OutStreamer,
                                  const llvm::MachineInstr &MI) {
  unsigned Opcode = MI.getOpcode();
  assert(STI->hasMOPS());
  assert(STI->hasMTE() || Opcode != AArch64::MOPSMemorySetTaggingPseudo);
 
  const auto Ops = [Opcode]() -> std::array<unsigned, 3> {
    if (Opcode == AArch64::MOPSMemoryCopyPseudo)
      return {AArch64::CPYFP, AArch64::CPYFM, AArch64::CPYFE};
    if (Opcode == AArch64::MOPSMemoryMovePseudo)
      return {AArch64::CPYP, AArch64::CPYM, AArch64::CPYE};
    if (Opcode == AArch64::MOPSMemorySetPseudo)
      return {AArch64::SETP, AArch64::SETM, AArch64::SETE};
    if (Opcode == AArch64::MOPSMemorySetTaggingPseudo)
      return {AArch64::SETGP, AArch64::SETGM, AArch64::MOPSSETGE};
    llvm_unreachable("Unhandled memory operation pseudo");
  }();
  const bool IsSet = Opcode == AArch64::MOPSMemorySetPseudo ||
                     Opcode == AArch64::MOPSMemorySetTaggingPseudo;
 
  for (auto Op : Ops) {
    int i = 0;
    auto MCIB = MCInstBuilder(Op);
    // Destination registers
    MCIB.addReg(MI.getOperand(i++).getReg());
    MCIB.addReg(MI.getOperand(i++).getReg());
    if (!IsSet)
      MCIB.addReg(MI.getOperand(i++).getReg());
    // Input registers
    MCIB.addReg(MI.getOperand(i++).getReg());
    MCIB.addReg(MI.getOperand(i++).getReg());
    MCIB.addReg(MI.getOperand(i++).getReg());
 
    EmitToStreamer(OutStreamer, MCIB);
  }
}
 
void AArch64AsmPrinter::LowerSTACKMAP(MCStreamer &OutStreamer, StackMaps &SM,
                                      const MachineInstr &MI) {
  unsigned NumNOPBytes = StackMapOpers(&MI).getNumPatchBytes();
 
  auto &Ctx = OutStreamer.getContext();
  MCSymbol *MILabel = Ctx.createTempSymbol();
  OutStreamer.emitLabel(MILabel);
 
  SM.recordStackMap(*MILabel, MI);
  assert(NumNOPBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
 
  // Scan ahead to trim the shadow.
  const MachineBasicBlock &MBB = *MI.getParent();
  MachineBasicBlock::const_iterator MII(MI);
  ++MII;
  while (NumNOPBytes > 0) {
    if (MII == MBB.end() || MII->isCall() ||
        MII->getOpcode() == AArch64::DBG_VALUE ||
        MII->getOpcode() == TargetOpcode::PATCHPOINT ||
        MII->getOpcode() == TargetOpcode::STACKMAP)
      break;
    ++MII;
    NumNOPBytes -= 4;
  }
 
  // Emit nops.
  for (unsigned i = 0; i < NumNOPBytes; i += 4)
    EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::NOP));
}
 
// Lower a patchpoint of the form:
// [<def>], <id>, <numBytes>, <target>, <numArgs>
void AArch64AsmPrinter::LowerPATCHPOINT(MCStreamer &OutStreamer, StackMaps &SM,
                                        const MachineInstr &MI) {
  auto &Ctx = OutStreamer.getContext();
  MCSymbol *MILabel = Ctx.createTempSymbol();
  OutStreamer.emitLabel(MILabel);
  SM.recordPatchPoint(*MILabel, MI);
 
  PatchPointOpers Opers(&MI);
 
  int64_t CallTarget = Opers.getCallTarget().getImm();
  unsigned EncodedBytes = 0;
  if (CallTarget) {
    assert((CallTarget & 0xFFFFFFFFFFFF) == CallTarget &&
           "High 16 bits of call target should be zero.");
    Register ScratchReg = MI.getOperand(Opers.getNextScratchIdx()).getReg();
    EncodedBytes = 16;
    // Materialize the jump address:
    emitMOVZ(ScratchReg, (CallTarget >> 32) & 0xFFFF, 32);
    emitMOVK(ScratchReg, (CallTarget >> 16) & 0xFFFF, 16);
    emitMOVK(ScratchReg, CallTarget & 0xFFFF, 0);
    EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::BLR).addReg(ScratchReg));
  }
  // Emit padding.
  unsigned NumBytes = Opers.getNumPatchBytes();
  assert(NumBytes >= EncodedBytes &&
         "Patchpoint can't request size less than the length of a call.");
  assert((NumBytes - EncodedBytes) % 4 == 0 &&
         "Invalid number of NOP bytes requested!");
  for (unsigned i = EncodedBytes; i < NumBytes; i += 4)
    EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::NOP));
}
 
void AArch64AsmPrinter::LowerSTATEPOINT(MCStreamer &OutStreamer, StackMaps &SM,
                                        const MachineInstr &MI) {
  StatepointOpers SOpers(&MI);
  if (unsigned PatchBytes = SOpers.getNumPatchBytes()) {
    assert(PatchBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
    for (unsigned i = 0; i < PatchBytes; i += 4)
      EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::NOP));
  } else {
    // Lower call target and choose correct opcode
    const MachineOperand &CallTarget = SOpers.getCallTarget();
    MCOperand CallTargetMCOp;
    unsigned CallOpcode;
    switch (CallTarget.getType()) {
    case MachineOperand::MO_GlobalAddress:
    case MachineOperand::MO_ExternalSymbol:
      MCInstLowering.lowerOperand(CallTarget, CallTargetMCOp);
      CallOpcode = AArch64::BL;
      break;
    case MachineOperand::MO_Immediate:
      CallTargetMCOp = MCOperand::createImm(CallTarget.getImm());
      CallOpcode = AArch64::BL;
      break;
    case MachineOperand::MO_Register:
      CallTargetMCOp = MCOperand::createReg(CallTarget.getReg());
      CallOpcode = AArch64::BLR;
      break;
    default:
      llvm_unreachable("Unsupported operand type in statepoint call target");
      break;
    }
 
    EmitToStreamer(OutStreamer,
                   MCInstBuilder(CallOpcode).addOperand(CallTargetMCOp));
  }
 
  auto &Ctx = OutStreamer.getContext();
  MCSymbol *MILabel = Ctx.createTempSymbol();
  OutStreamer.emitLabel(MILabel);
  SM.recordStatepoint(*MILabel, MI);
}
 
void AArch64AsmPrinter::LowerFAULTING_OP(const MachineInstr &FaultingMI) {
  // FAULTING_LOAD_OP <def>, <faltinf type>, <MBB handler>,
  //                  <opcode>, <operands>
 
  Register DefRegister = FaultingMI.getOperand(0).getReg();
  FaultMaps::FaultKind FK =
      static_cast<FaultMaps::FaultKind>(FaultingMI.getOperand(1).getImm());
  MCSymbol *HandlerLabel = FaultingMI.getOperand(2).getMBB()->getSymbol();
  unsigned Opcode = FaultingMI.getOperand(3).getImm();
  unsigned OperandsBeginIdx = 4;
 
  auto &Ctx = OutStreamer->getContext();
  MCSymbol *FaultingLabel = Ctx.createTempSymbol();
  OutStreamer->emitLabel(FaultingLabel);
 
  assert(FK < FaultMaps::FaultKindMax && "Invalid Faulting Kind!");
  FM.recordFaultingOp(FK, FaultingLabel, HandlerLabel);
 
  MCInst MI;
  MI.setOpcode(Opcode);
 
  if (DefRegister != (Register)0)
    MI.addOperand(MCOperand::createReg(DefRegister));
 
  for (const MachineOperand &MO :
       llvm::drop_begin(FaultingMI.operands(), OperandsBeginIdx)) {
    MCOperand Dest;
    lowerOperand(MO, Dest);
    MI.addOperand(Dest);
  }
 
  OutStreamer->AddComment("on-fault: " + HandlerLabel->getName());
  EmitToStreamer(MI);
}
 
void AArch64AsmPrinter::emitMovXReg(Register Dest, Register Src) {
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ORRXrs)
                                   .addReg(Dest)
                                   .addReg(AArch64::XZR)
                                   .addReg(Src)
                                   .addImm(0));
}
 
void AArch64AsmPrinter::emitMOVZ(Register Dest, uint64_t Imm, unsigned Shift) {
  bool Is64Bit = AArch64::GPR64RegClass.contains(Dest);
  EmitToStreamer(*OutStreamer,
                 MCInstBuilder(Is64Bit ? AArch64::MOVZXi : AArch64::MOVZWi)
                     .addReg(Dest)
                     .addImm(Imm)
                     .addImm(Shift));
}
 
void AArch64AsmPrinter::emitMOVK(Register Dest, uint64_t Imm, unsigned Shift) {
  bool Is64Bit = AArch64::GPR64RegClass.contains(Dest);
  EmitToStreamer(*OutStreamer,
                 MCInstBuilder(Is64Bit ? AArch64::MOVKXi : AArch64::MOVKWi)
                     .addReg(Dest)
                     .addReg(Dest)
                     .addImm(Imm)
                     .addImm(Shift));
}
 
void AArch64AsmPrinter::emitAUT(AArch64PACKey::ID Key, Register Pointer,
                                Register Disc) {
  bool IsZeroDisc = Disc == AArch64::XZR;
  unsigned Opcode = getAUTOpcodeForKey(Key, IsZeroDisc);
 
  //  autiza x16       ; if  IsZeroDisc
  //  autia  x16, x17  ; if !IsZeroDisc
  MCInst AUTInst;
  AUTInst.setOpcode(Opcode);
  AUTInst.addOperand(MCOperand::createReg(Pointer));
  AUTInst.addOperand(MCOperand::createReg(Pointer));
  if (!IsZeroDisc)
    AUTInst.addOperand(MCOperand::createReg(Disc));
 
  EmitToStreamer(AUTInst);
}
 
void AArch64AsmPrinter::emitPAC(AArch64PACKey::ID Key, Register Pointer,
                                Register Disc) {
  bool IsZeroDisc = Disc == AArch64::XZR;
  unsigned Opcode = getPACOpcodeForKey(Key, IsZeroDisc);
 
  //  paciza x16       ; if  IsZeroDisc
  //  pacia  x16, x17  ; if !IsZeroDisc
  MCInst PACInst;
  PACInst.setOpcode(Opcode);
  PACInst.addOperand(MCOperand::createReg(Pointer));
  PACInst.addOperand(MCOperand::createReg(Pointer));
  if (!IsZeroDisc)
    PACInst.addOperand(MCOperand::createReg(Disc));
 
  EmitToStreamer(PACInst);
}
 
void AArch64AsmPrinter::emitBLRA(bool IsCall, AArch64PACKey::ID Key,
                                 Register Target, Register Disc) {
  bool IsZeroDisc = Disc == AArch64::XZR;
  unsigned Opcode = getBranchOpcodeForKey(IsCall, Key, IsZeroDisc);
 
  //  blraaz x16       ; if  IsZeroDisc
  //  blraa  x16, x17  ; if !IsZeroDisc
  MCInst Inst;
  Inst.setOpcode(Opcode);
  Inst.addOperand(MCOperand::createReg(Target));
  if (!IsZeroDisc)
    Inst.addOperand(MCOperand::createReg(Disc));
  EmitToStreamer(Inst);
}
 
void AArch64AsmPrinter::emitFMov0(const MachineInstr &MI) {
  Register DestReg = MI.getOperand(0).getReg();
  if (!STI->hasZeroCycleZeroingFPWorkaround() && STI->isNeonAvailable()) {
    if (STI->hasZeroCycleZeroingFPR64()) {
      // Convert H/S register to corresponding D register
      const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
      if (AArch64::FPR16RegClass.contains(DestReg))
        DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::hsub,
                                           &AArch64::FPR64RegClass);
      else if (AArch64::FPR32RegClass.contains(DestReg))
        DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::ssub,
                                           &AArch64::FPR64RegClass);
      else
        assert(AArch64::FPR64RegClass.contains(DestReg));
 
      MCInst MOVI;
      MOVI.setOpcode(AArch64::MOVID);
      MOVI.addOperand(MCOperand::createReg(DestReg));
      MOVI.addOperand(MCOperand::createImm(0));
      EmitToStreamer(*OutStreamer, MOVI);
      ++NumZCZeroingInstrsFPR;
    } else if (STI->hasZeroCycleZeroingFPR128()) {
      // Convert H/S/D register to corresponding Q register
      const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
      if (AArch64::FPR16RegClass.contains(DestReg)) {
        DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::hsub,
                                           &AArch64::FPR128RegClass);
      } else if (AArch64::FPR32RegClass.contains(DestReg)) {
        DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::ssub,
                                           &AArch64::FPR128RegClass);
      } else {
        assert(AArch64::FPR64RegClass.contains(DestReg));
        DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::dsub,
                                           &AArch64::FPR128RegClass);
      }
 
      MCInst MOVI;
      MOVI.setOpcode(AArch64::MOVIv2d_ns);
      MOVI.addOperand(MCOperand::createReg(DestReg));
      MOVI.addOperand(MCOperand::createImm(0));
      EmitToStreamer(*OutStreamer, MOVI);
      ++NumZCZeroingInstrsFPR;
    } else {
      emitFMov0AsFMov(MI, DestReg);
    }
  } else {
    emitFMov0AsFMov(MI, DestReg);
  }
}
 
void AArch64AsmPrinter::emitFMov0AsFMov(const MachineInstr &MI,
                                        Register DestReg) {
  MCInst FMov;
  switch (MI.getOpcode()) {
  default:
    llvm_unreachable("Unexpected opcode");
  case AArch64::FMOVH0:
    FMov.setOpcode(STI->hasFullFP16() ? AArch64::FMOVWHr : AArch64::FMOVWSr);
    if (!STI->hasFullFP16())
      DestReg = (AArch64::S0 + (DestReg - AArch64::H0));
    FMov.addOperand(MCOperand::createReg(DestReg));
    FMov.addOperand(MCOperand::createReg(AArch64::WZR));
    break;
  case AArch64::FMOVS0:
    FMov.setOpcode(AArch64::FMOVWSr);
    FMov.addOperand(MCOperand::createReg(DestReg));
    FMov.addOperand(MCOperand::createReg(AArch64::WZR));
    break;
  case AArch64::FMOVD0:
    FMov.setOpcode(AArch64::FMOVXDr);
    FMov.addOperand(MCOperand::createReg(DestReg));
    FMov.addOperand(MCOperand::createReg(AArch64::XZR));
    break;
  }
  EmitToStreamer(*OutStreamer, FMov);
}
 
Register AArch64AsmPrinter::emitPtrauthDiscriminator(uint64_t Disc,
                                                     Register AddrDisc,
                                                     Register ScratchReg,
                                                     bool MayClobberAddrDisc) {
  assert(isPtrauthRegSafe(ScratchReg) &&
         "Safe scratch register must be provided by the caller");
  assert(isUInt<16>(Disc) && "Constant discriminator is too wide");
 
  // So far we've used NoRegister in pseudos.  Now we need real encodings.
  if (AddrDisc == AArch64::NoRegister)
    AddrDisc = AArch64::XZR;
 
  // If there is no constant discriminator, there's no blend involved:
  // just use the address discriminator register as-is (XZR or not).
  if (!Disc)
    return AddrDisc;
 
  // If there's only a constant discriminator, MOV it into the scratch register.
  if (AddrDisc == AArch64::XZR) {
    emitMOVZ(ScratchReg, Disc, 0);
    return ScratchReg;
  }
 
  // If there are both, emit a blend into the scratch register.
 
  // Check if we can save one MOV instruction.
  if (MayClobberAddrDisc && isPtrauthRegSafe(AddrDisc)) {
    ScratchReg = AddrDisc;
  } else {
    emitMovXReg(ScratchReg, AddrDisc);
    assert(ScratchReg != AddrDisc &&
           "Forbidden to clobber AddrDisc, but have to");
  }
 
  emitMOVK(ScratchReg, Disc, 48);
  return ScratchReg;
}
 
/// Emit a code sequence to check an authenticated pointer value.
///
/// This function emits a sequence of instructions that checks if TestedReg was
/// authenticated successfully. On success, execution continues at the next
/// instruction after the sequence.
///
/// The action performed on failure depends on the OnFailure argument:
/// * if OnFailure is not nullptr, control is transferred to that label after
///   clearing the PAC field
/// * otherwise, BRK instruction is emitted to generate an error
void AArch64AsmPrinter::emitPtrauthCheckAuthenticatedValue(
    Register TestedReg, Register ScratchReg, AArch64PACKey::ID Key,
    AArch64PAuth::AuthCheckMethod Method, const MCSymbol *OnFailure) {
  // Insert a sequence to check if authentication of TestedReg succeeded,
  // such as:
  //
  // - checked and clearing:
  //      ; x16 is TestedReg, x17 is ScratchReg
  //      mov x17, x16
  //      xpaci x17
  //      cmp x16, x17
  //      b.eq Lsuccess
  //      mov x16, x17
  //      b Lend
  //    Lsuccess:
  //      ; skipped if authentication failed
  //    Lend:
  //      ...
  //
  // - checked and trapping:
  //      mov x17, x16
  //      xpaci x17
  //      cmp x16, x17
  //      b.eq Lsuccess
  //      brk #<0xc470 + aut key>
  //    Lsuccess:
  //      ...
  //
  // See the documentation on AuthCheckMethod enumeration constants for
  // the specific code sequences that can be used to perform the check.
  using AArch64PAuth::AuthCheckMethod;
 
  if (Method == AuthCheckMethod::None)
    return;
  if (Method == AuthCheckMethod::DummyLoad) {
    EmitToStreamer(MCInstBuilder(AArch64::LDRWui)
                       .addReg(getWRegFromXReg(ScratchReg))
                       .addReg(TestedReg)
                       .addImm(0));
    assert(!OnFailure && "DummyLoad always traps on error");
    return;
  }
 
  MCSymbol *SuccessSym = createTempSymbol("auth_success_");
  if (Method == AuthCheckMethod::XPAC || Method == AuthCheckMethod::XPACHint) {
    //  mov Xscratch, Xtested
    emitMovXReg(ScratchReg, TestedReg);
 
    if (Method == AuthCheckMethod::XPAC) {
      //  xpac(i|d) Xscratch
      unsigned XPACOpc = getXPACOpcodeForKey(Key);
      EmitToStreamer(
          MCInstBuilder(XPACOpc).addReg(ScratchReg).addReg(ScratchReg));
    } else {
      //  xpaclri
 
      // Note that this method applies XPAC to TestedReg instead of ScratchReg.
      assert(TestedReg == AArch64::LR &&
             "XPACHint mode is only compatible with checking the LR register");
      assert((Key == AArch64PACKey::IA || Key == AArch64PACKey::IB) &&
             "XPACHint mode is only compatible with I-keys");
      EmitToStreamer(MCInstBuilder(AArch64::XPACLRI));
    }
 
    //  cmp Xtested, Xscratch
    EmitToStreamer(MCInstBuilder(AArch64::SUBSXrs)
                       .addReg(AArch64::XZR)
                       .addReg(TestedReg)
                       .addReg(ScratchReg)
                       .addImm(0));
 
    //  b.eq Lsuccess
    EmitToStreamer(
        MCInstBuilder(AArch64::Bcc)
            .addImm(AArch64CC::EQ)
            .addExpr(MCSymbolRefExpr::create(SuccessSym, OutContext)));
  } else if (Method == AuthCheckMethod::HighBitsNoTBI) {
    //  eor Xscratch, Xtested, Xtested, lsl #1
    EmitToStreamer(MCInstBuilder(AArch64::EORXrs)
                       .addReg(ScratchReg)
                       .addReg(TestedReg)
                       .addReg(TestedReg)
                       .addImm(1));
    //  tbz Xscratch, #62, Lsuccess
    EmitToStreamer(
        MCInstBuilder(AArch64::TBZX)
            .addReg(ScratchReg)
            .addImm(62)
            .addExpr(MCSymbolRefExpr::create(SuccessSym, OutContext)));
  } else {
    llvm_unreachable("Unsupported check method");
  }
 
  if (!OnFailure) {
    // Trapping sequences do a 'brk'.
    //  brk #<0xc470 + aut key>
    EmitToStreamer(MCInstBuilder(AArch64::BRK).addImm(0xc470 | Key));
  } else {
    // Non-trapping checked sequences return the stripped result in TestedReg,
    // skipping over success-only code (such as re-signing the pointer) by
    // jumping to OnFailure label.
    // Note that this can introduce an authentication oracle (such as based on
    // the high bits of the re-signed value).
 
    // FIXME: The XPAC method can be optimized by applying XPAC to TestedReg
    //        instead of ScratchReg, thus eliminating one `mov` instruction.
    //        Both XPAC and XPACHint can be further optimized by not using a
    //        conditional branch jumping over an unconditional one.
 
    switch (Method) {
    case AuthCheckMethod::XPACHint:
      // LR is already XPAC-ed at this point.
      break;
    case AuthCheckMethod::XPAC:
      //  mov Xtested, Xscratch
      emitMovXReg(TestedReg, ScratchReg);
      break;
    default:
      // If Xtested was not XPAC-ed so far, emit XPAC here.
      //  xpac(i|d) Xtested
      unsigned XPACOpc = getXPACOpcodeForKey(Key);
      EmitToStreamer(
          MCInstBuilder(XPACOpc).addReg(TestedReg).addReg(TestedReg));
    }
 
    //  b Lend
    const auto *OnFailureExpr = MCSymbolRefExpr::create(OnFailure, OutContext);
    EmitToStreamer(MCInstBuilder(AArch64::B).addExpr(OnFailureExpr));
  }
 
  // If the auth check succeeds, we can continue.
  // Lsuccess:
  OutStreamer->emitLabel(SuccessSym);
}
 
// With Pointer Authentication, it may be needed to explicitly check the
// authenticated value in LR before performing a tail call.
// Otherwise, the callee may re-sign the invalid return address,
// introducing a signing oracle.
void AArch64AsmPrinter::emitPtrauthTailCallHardening(const MachineInstr *TC) {
  if (!AArch64FI->shouldSignReturnAddress(*MF))
    return;
 
  auto LRCheckMethod = STI->getAuthenticatedLRCheckMethod(*MF);
  if (LRCheckMethod == AArch64PAuth::AuthCheckMethod::None)
    return;
 
  const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
  Register ScratchReg =
      TC->readsRegister(AArch64::X16, TRI) ? AArch64::X17 : AArch64::X16;
  assert(!TC->readsRegister(ScratchReg, TRI) &&
         "Neither x16 nor x17 is available as a scratch register");
  AArch64PACKey::ID Key =
      AArch64FI->shouldSignWithBKey() ? AArch64PACKey::IB : AArch64PACKey::IA;
  emitPtrauthCheckAuthenticatedValue(AArch64::LR, ScratchReg, Key,
                                     LRCheckMethod);
}
 
bool AArch64AsmPrinter::emitDeactivationSymbolRelocation(Value *DS) {
  if (!DS)
    return false;
 
  if (isa<GlobalAlias>(DS)) {
    // Just emit the nop directly.
    EmitToStreamer(MCInstBuilder(AArch64::NOP));
    return true;
  }
  MCSymbol *Dot = OutContext.createTempSymbol();
  OutStreamer->emitLabel(Dot);
  const MCExpr *DeactDotExpr = MCSymbolRefExpr::create(Dot, OutContext);
 
  const MCExpr *DSExpr = MCSymbolRefExpr::create(
      OutContext.getOrCreateSymbol(DS->getName()), OutContext);
  OutStreamer->emitRelocDirective(*DeactDotExpr, "R_AARCH64_PATCHINST", DSExpr,
                                  SMLoc());
  return false;
}
 
AArch64AsmPrinter::PtrAuthSchema::PtrAuthSchema(
    AArch64PACKey::ID Key, uint64_t IntDisc, const MachineOperand &AddrDiscOp)
    : Key(Key), IntDisc(IntDisc), AddrDisc(AddrDiscOp.getReg()),
      AddrDiscIsKilled(AddrDiscOp.isKill()) {}
 
void AArch64AsmPrinter::emitPtrauthAuthResign(
    Register Pointer, Register Scratch, PtrAuthSchema AuthSchema,
    std::optional<PtrAuthSchema> SignSchema, Value *DS) {
  const bool IsResign = SignSchema.has_value();
 
  // We expand AUT/AUTPAC into a sequence of the form
  //
  //      ; authenticate x16
  //      ; check pointer in x16
  //    Lsuccess:
  //      ; sign x16 (if AUTPAC)
  //    Lend:   ; if not trapping on failure
  //
  // with the checking sequence chosen depending on whether/how we should check
  // the pointer and whether we should trap on failure.
 
  // By default, auth/resign sequences check for auth failures.
  bool ShouldCheck = true;
  // In the checked sequence, we only trap if explicitly requested.
  bool ShouldTrap = MF->getFunction().hasFnAttribute("ptrauth-auth-traps");
 
  // On an FPAC CPU, you get traps whether you want them or not: there's
  // no point in emitting checks or traps.
  if (STI->hasFPAC())
    ShouldCheck = ShouldTrap = false;
 
  // However, command-line flags can override this, for experimentation.
  switch (PtrauthAuthChecks) {
  case PtrauthCheckMode::Default:
    break;
  case PtrauthCheckMode::Unchecked:
    ShouldCheck = ShouldTrap = false;
    break;
  case PtrauthCheckMode::Poison:
    ShouldCheck = true;
    ShouldTrap = false;
    break;
  case PtrauthCheckMode::Trap:
    ShouldCheck = ShouldTrap = true;
    break;
  }
 
  // Compute aut discriminator
  Register AUTDiscReg =
      emitPtrauthDiscriminator(AuthSchema.IntDisc, AuthSchema.AddrDisc, Scratch,
                               AuthSchema.AddrDiscIsKilled);
 
  if (!emitDeactivationSymbolRelocation(DS))
    emitAUT(AuthSchema.Key, Pointer, AUTDiscReg);
 
  // Unchecked or checked-but-non-trapping AUT is just an "AUT": we're done.
  if (!IsResign && (!ShouldCheck || !ShouldTrap))
    return;
 
  MCSymbol *EndSym = nullptr;
 
  if (ShouldCheck) {
    if (IsResign && !ShouldTrap)
      EndSym = createTempSymbol("resign_end_");
 
    emitPtrauthCheckAuthenticatedValue(Pointer, Scratch, AuthSchema.Key,
                                       AArch64PAuth::AuthCheckMethod::XPAC,
                                       EndSym);
  }
 
  // We already emitted unchecked and checked-but-non-trapping AUTs.
  // That left us with trapping AUTs, and AUTPACs.
  // Trapping AUTs don't need PAC: we're done.
  if (!IsResign)
    return;
 
  // Compute pac discriminator
  Register PACDiscReg = emitPtrauthDiscriminator(SignSchema->IntDisc,
                                                 SignSchema->AddrDisc, Scratch);
  emitPAC(SignSchema->Key, Pointer, PACDiscReg);
 
  //  Lend:
  if (EndSym)
    OutStreamer->emitLabel(EndSym);
}
 
void AArch64AsmPrinter::emitPtrauthSign(const MachineInstr *MI) {
  Register Val = MI->getOperand(1).getReg();
  auto Key = (AArch64PACKey::ID)MI->getOperand(2).getImm();
  uint64_t Disc = MI->getOperand(3).getImm();
  Register AddrDisc = MI->getOperand(4).getReg();
  bool AddrDiscKilled = MI->getOperand(4).isKill();
 
  // As long as at least one of Val and AddrDisc is in GPR64noip, a scratch
  // register is available.
  Register ScratchReg = Val == AArch64::X16 ? AArch64::X17 : AArch64::X16;
  assert(ScratchReg != AddrDisc &&
         "Neither X16 nor X17 is available as a scratch register");
 
  // Compute pac discriminator
  Register DiscReg = emitPtrauthDiscriminator(
      Disc, AddrDisc, ScratchReg, /*MayClobberAddrDisc=*/AddrDiscKilled);
 
  if (emitDeactivationSymbolRelocation(MI->getDeactivationSymbol()))
    return;
 
  emitPAC(Key, Val, DiscReg);
}
 
void AArch64AsmPrinter::emitPtrauthBranch(const MachineInstr *MI) {
  bool IsCall = MI->getOpcode() == AArch64::BLRA;
  unsigned BrTarget = MI->getOperand(0).getReg();
 
  auto Key = (AArch64PACKey::ID)MI->getOperand(1).getImm();
  uint64_t Disc = MI->getOperand(2).getImm();
 
  unsigned AddrDisc = MI->getOperand(3).getReg();
 
  // Make sure AddrDisc is solely used to compute the discriminator.
  // While hardly meaningful, it is still possible to describe an authentication
  // of a pointer against its own value (instead of storage address) with
  // intrinsics, so use report_fatal_error instead of assert.
  if (BrTarget == AddrDisc)
    report_fatal_error("Branch target is signed with its own value");
 
  // If we are printing BLRA pseudo, try to save one MOV by making use of the
  // fact that x16 and x17 are described as clobbered by the MI instruction and
  // AddrDisc is not used as any other input.
  //
  // Back in the day, emitPtrauthDiscriminator was restricted to only returning
  // either x16 or x17, meaning the returned register is always among the
  // implicit-def'ed registers of BLRA pseudo. Now this property can be violated
  // if isX16X17Safer predicate is false, thus manually check if AddrDisc is
  // among x16 and x17 to prevent clobbering unexpected registers.
  //
  // Unlike BLRA, BRA pseudo is used to perform computed goto, and thus not
  // declared as clobbering x16/x17.
  //
  // FIXME: Make use of `killed` flags and register masks instead.
  bool AddrDiscIsImplicitDef =
      IsCall && (AddrDisc == AArch64::X16 || AddrDisc == AArch64::X17);
  Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, AArch64::X17,
                                              AddrDiscIsImplicitDef);
  emitBLRA(IsCall, Key, BrTarget, DiscReg);
}
 
void AArch64AsmPrinter::emitAddImm(MCRegister Reg, int64_t Addend,
                                   MCRegister Tmp) {
  if (Addend != 0) {
    const uint64_t AbsOffset = (Addend > 0 ? Addend : -((uint64_t)Addend));
    const bool IsNeg = Addend < 0;
    if (isUInt<24>(AbsOffset)) {
      for (int BitPos = 0; BitPos != 24 && (AbsOffset >> BitPos);
           BitPos += 12) {
        EmitToStreamer(
            MCInstBuilder(IsNeg ? AArch64::SUBXri : AArch64::ADDXri)
                .addReg(Reg)
                .addReg(Reg)
                .addImm((AbsOffset >> BitPos) & 0xfff)
                .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, BitPos)));
      }
    } else {
      const uint64_t UAddend = Addend;
      EmitToStreamer(MCInstBuilder(IsNeg ? AArch64::MOVNXi : AArch64::MOVZXi)
                         .addReg(Tmp)
                         .addImm((IsNeg ? ~UAddend : UAddend) & 0xffff)
                         .addImm(/*shift=*/0));
      auto NeedMovk = [IsNeg, UAddend](int BitPos) -> bool {
        assert(BitPos == 16 || BitPos == 32 || BitPos == 48);
        uint64_t Shifted = UAddend >> BitPos;
        if (!IsNeg)
          return Shifted != 0;
        for (int I = 0; I != 64 - BitPos; I += 16)
          if (((Shifted >> I) & 0xffff) != 0xffff)
            return true;
        return false;
      };
      for (int BitPos = 16; BitPos != 64 && NeedMovk(BitPos); BitPos += 16)
        emitMOVK(Tmp, (UAddend >> BitPos) & 0xffff, BitPos);
 
      EmitToStreamer(MCInstBuilder(AArch64::ADDXrs)
                         .addReg(Reg)
                         .addReg(Reg)
                         .addReg(Tmp)
                         .addImm(/*shift=*/0));
    }
  }
}
 
void AArch64AsmPrinter::emitAddress(MCRegister Reg, const MCExpr *Expr,
                                    MCRegister Tmp, bool DSOLocal,
                                    const MCSubtargetInfo &STI) {
  MCValue Val;
  if (!Expr->evaluateAsRelocatable(Val, nullptr))
    report_fatal_error("emitAddress could not evaluate");
  if (DSOLocal) {
    EmitToStreamer(
        MCInstBuilder(AArch64::ADRP)
            .addReg(Reg)
            .addExpr(MCSpecifierExpr::create(Expr, AArch64::S_ABS_PAGE,
                                             OutStreamer->getContext())));
    EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                       .addReg(Reg)
                       .addReg(Reg)
                       .addExpr(MCSpecifierExpr::create(
                           Expr, AArch64::S_LO12, OutStreamer->getContext()))
                       .addImm(0));
  } else {
    auto *SymRef =
        MCSymbolRefExpr::create(Val.getAddSym(), OutStreamer->getContext());
    EmitToStreamer(
        MCInstBuilder(AArch64::ADRP)
            .addReg(Reg)
            .addExpr(MCSpecifierExpr::create(SymRef, AArch64::S_GOT_PAGE,
                                             OutStreamer->getContext())));
    EmitToStreamer(
        MCInstBuilder(AArch64::LDRXui)
            .addReg(Reg)
            .addReg(Reg)
            .addExpr(MCSpecifierExpr::create(SymRef, AArch64::S_GOT_LO12,
                                             OutStreamer->getContext())));
    emitAddImm(Reg, Val.getConstant(), Tmp);
  }
}
 
static bool targetSupportsIRelativeRelocation(const Triple &TT) {
  // IFUNCs are ELF-only.
  if (!TT.isOSBinFormatELF())
    return false;
 
  // IFUNCs are supported on glibc, bionic, and some but not all of the BSDs.
  return TT.isOSGlibc() || TT.isAndroid() || TT.isOSFreeBSD() ||
         TT.isOSDragonFly() || TT.isOSNetBSD();
}
 
// Emit an ifunc resolver that returns a signed pointer to the specified target,
// and return a FUNCINIT reference to the resolver. In the linked binary, this
// function becomes the target of an IRELATIVE relocation. This resolver is used
// to relocate signed pointers in global variable initializers in special cases
// where the standard R_AARCH64_AUTH_ABS64 relocation would not work.
//
// Example (signed null pointer, not address discriminated):
//
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// mov x1, #12345
// b __emupac_pacda
//
// Example (signed null pointer, address discriminated):
//
// .Ltmp:
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// adrp x1, .Ltmp
// add x1, x1, :lo12:.Ltmp
// b __emupac_pacda
// .popsection
//
// Example (signed pointer to symbol, not address discriminated):
//
// .Ltmp:
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// adrp x0, symbol
// add x0, x0, :lo12:symbol
// mov x1, #12345
// b __emupac_pacda
// .popsection
//
// Example (signed null pointer, not address discriminated, with deactivation
// symbol ds):
//
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// mov x1, #12345
// .reloc ., R_AARCH64_PATCHINST, ds
// b __emupac_pacda
// ret
// .popsection
const MCExpr *AArch64AsmPrinter::emitPAuthRelocationAsIRelative(
    const MCExpr *Target, uint64_t Disc, AArch64PACKey::ID KeyID,
    bool HasAddressDiversity, bool IsDSOLocal, const MCExpr *DSExpr) {
  const Triple &TT = TM.getTargetTriple();
 
  // We only emit an IRELATIVE relocation if the target supports IRELATIVE.
  if (!targetSupportsIRelativeRelocation(TT))
    return nullptr;
 
  // For now, only the DA key is supported.
  if (KeyID != AArch64PACKey::DA)
    return nullptr;
 
  // AArch64Subtarget is huge, so heap allocate it so we don't run out of stack
  // space.
  auto STI = std::make_unique<AArch64Subtarget>(
      TT, TM.getTargetCPU(), TM.getTargetCPU(), TM.getTargetFeatureString(), TM,
      true);
  this->STI = STI.get();
 
  MCSymbol *Place = OutStreamer->getContext().createTempSymbol();
  OutStreamer->emitLabel(Place);
  OutStreamer->pushSection();
 
  const MCSymbolELF *Group =
      static_cast<MCSectionELF *>(OutStreamer->getCurrentSectionOnly())
          ->getGroup();
  auto Flags = ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
  if (Group)
    Flags |= ELF::SHF_GROUP;
  OutStreamer->switchSection(OutStreamer->getContext().getELFSection(
      ".text.startup", ELF::SHT_PROGBITS, Flags, 0, Group, true,
      Group ? MCSection::NonUniqueID : PAuthIFuncNextUniqueID++, nullptr));
 
  MCSymbol *IRelativeSym =
      OutStreamer->getContext().createLinkerPrivateSymbol("pauth_ifunc");
  OutStreamer->emitLabel(IRelativeSym);
  if (isa<MCConstantExpr>(Target)) {
    OutStreamer->emitInstruction(MCInstBuilder(AArch64::MOVZXi)
                                     .addReg(AArch64::X0)
                                     .addExpr(Target)
                                     .addImm(0),
                                 *STI);
  } else {
    emitAddress(AArch64::X0, Target, AArch64::X16, IsDSOLocal, *STI);
  }
  if (HasAddressDiversity) {
    auto *PlacePlusDisc = MCBinaryExpr::createAdd(
        MCSymbolRefExpr::create(Place, OutStreamer->getContext()),
        MCConstantExpr::create(Disc, OutStreamer->getContext()),
        OutStreamer->getContext());
    emitAddress(AArch64::X1, PlacePlusDisc, AArch64::X16, /*IsDSOLocal=*/true,
                *STI);
  } else {
    if (!isUInt<16>(Disc)) {
      OutContext.reportError(SMLoc(), "AArch64 PAC Discriminator '" +
                                          Twine(Disc) +
                                          "' out of range [0, 0xFFFF]");
    }
    emitMOVZ(AArch64::X1, Disc, 0);
  }
 
  if (DSExpr) {
    MCSymbol *PrePACInst = OutStreamer->getContext().createTempSymbol();
    OutStreamer->emitLabel(PrePACInst);
 
    auto *PrePACInstExpr =
        MCSymbolRefExpr::create(PrePACInst, OutStreamer->getContext());
    OutStreamer->emitRelocDirective(*PrePACInstExpr, "R_AARCH64_PATCHINST",
                                    DSExpr, SMLoc());
  }
 
  // We don't know the subtarget because this is being emitted for a global
  // initializer. Because the performance of IFUNC resolvers is unimportant, we
  // always call the EmuPAC runtime, which will end up using the PAC instruction
  // if the target supports PAC.
  MCSymbol *EmuPAC =
      OutStreamer->getContext().getOrCreateSymbol("__emupac_pacda");
  const MCSymbolRefExpr *EmuPACRef =
      MCSymbolRefExpr::create(EmuPAC, OutStreamer->getContext());
  OutStreamer->emitInstruction(MCInstBuilder(AArch64::B).addExpr(EmuPACRef),
                               *STI);
 
  // We need a RET despite the above tail call because the deactivation symbol
  // may replace the tail call with a NOP.
  if (DSExpr)
    OutStreamer->emitInstruction(
        MCInstBuilder(AArch64::RET).addReg(AArch64::LR), *STI);
  OutStreamer->popSection();
 
  return MCSymbolRefExpr::create(IRelativeSym, AArch64::S_FUNCINIT,
                                 OutStreamer->getContext());
}
 
const MCExpr *
AArch64AsmPrinter::lowerConstantPtrAuth(const ConstantPtrAuth &CPA) {
  MCContext &Ctx = OutContext;
 
  // Figure out the base symbol and the addend, if any.
  APInt Offset(64, 0);
  const Value *BaseGV = CPA.getPointer()->stripAndAccumulateConstantOffsets(
      getDataLayout(), Offset, /*AllowNonInbounds=*/true);
 
  auto *BaseGVB = dyn_cast<GlobalValue>(BaseGV);
 
  const MCExpr *Sym;
  if (BaseGVB) {
    // If there is an addend, turn that into the appropriate MCExpr.
    Sym = MCSymbolRefExpr::create(getSymbol(BaseGVB), Ctx);
    if (Offset.sgt(0))
      Sym = MCBinaryExpr::createAdd(
          Sym, MCConstantExpr::create(Offset.getSExtValue(), Ctx), Ctx);
    else if (Offset.slt(0))
      Sym = MCBinaryExpr::createSub(
          Sym, MCConstantExpr::create((-Offset).getSExtValue(), Ctx), Ctx);
  } else {
    Sym = MCConstantExpr::create(Offset.getSExtValue(), Ctx);
  }
 
  const MCExpr *DSExpr = nullptr;
  if (auto *DS = dyn_cast<GlobalValue>(CPA.getDeactivationSymbol())) {
    if (isa<GlobalAlias>(DS))
      return Sym;
    DSExpr = MCSymbolRefExpr::create(getSymbol(DS), Ctx);
  }
 
  uint64_t KeyID = CPA.getKey()->getZExtValue();
  // We later rely on valid KeyID value in AArch64PACKeyIDToString call from
  // AArch64AuthMCExpr::printImpl, so fail fast.
  if (KeyID > AArch64PACKey::LAST) {
    CPA.getContext().emitError("AArch64 PAC Key ID '" + Twine(KeyID) +
                               "' out of range [0, " +
                               Twine((unsigned)AArch64PACKey::LAST) + "]");
    KeyID = 0;
  }
 
  uint64_t Disc = CPA.getDiscriminator()->getZExtValue();
 
  // Check if we can represent this with an IRELATIVE and emit it if so.
  if (auto *IFuncSym = emitPAuthRelocationAsIRelative(
          Sym, Disc, AArch64PACKey::ID(KeyID), CPA.hasAddressDiscriminator(),
          BaseGVB && BaseGVB->isDSOLocal(), DSExpr))
    return IFuncSym;
 
  if (!isUInt<16>(Disc)) {
    CPA.getContext().emitError("AArch64 PAC Discriminator '" + Twine(Disc) +
                               "' out of range [0, 0xFFFF]");
    Disc = 0;
  }
 
  if (DSExpr)
    report_fatal_error("deactivation symbols unsupported in constant "
                       "expressions on this target");
 
  // Finally build the complete @AUTH expr.
  return AArch64AuthMCExpr::create(Sym, Disc, AArch64PACKey::ID(KeyID),
                                   CPA.hasAddressDiscriminator(), Ctx);
}
 
void AArch64AsmPrinter::LowerLOADauthptrstatic(const MachineInstr &MI) {
  unsigned DstReg = MI.getOperand(0).getReg();
  const MachineOperand &GAOp = MI.getOperand(1);
  const uint64_t KeyC = MI.getOperand(2).getImm();
  assert(KeyC <= AArch64PACKey::LAST &&
         "key is out of range [0, AArch64PACKey::LAST]");
  const auto Key = (AArch64PACKey::ID)KeyC;
  const uint64_t Disc = MI.getOperand(3).getImm();
  assert(isUInt<16>(Disc) &&
         "constant discriminator is out of range [0, 0xffff]");
 
  // Emit instruction sequence like the following:
  //   ADRP x16, symbol$auth_ptr$key$disc
  //   LDR x16, [x16, :lo12:symbol$auth_ptr$key$disc]
  //
  // Where the $auth_ptr$ symbol is the stub slot containing the signed pointer
  // to symbol.
  MCSymbol *AuthPtrStubSym;
  if (TM.getTargetTriple().isOSBinFormatELF()) {
    const auto &TLOF =
        static_cast<const AArch64_ELFTargetObjectFile &>(getObjFileLowering());
 
    assert(GAOp.getOffset() == 0 &&
           "non-zero offset for $auth_ptr$ stub slots is not supported");
    const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
    AuthPtrStubSym = TLOF.getAuthPtrSlotSymbol(TM, MMI, GASym, Key, Disc);
  } else {
    assert(TM.getTargetTriple().isOSBinFormatMachO() &&
           "LOADauthptrstatic is implemented only for MachO/ELF");
 
    const auto &TLOF = static_cast<const AArch64_MachoTargetObjectFile &>(
        getObjFileLowering());
 
    assert(GAOp.getOffset() == 0 &&
           "non-zero offset for $auth_ptr$ stub slots is not supported");
    const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
    AuthPtrStubSym = TLOF.getAuthPtrSlotSymbol(TM, MMI, GASym, Key, Disc);
  }
 
  MachineOperand StubMOHi =
      MachineOperand::CreateMCSymbol(AuthPtrStubSym, AArch64II::MO_PAGE);
  MachineOperand StubMOLo = MachineOperand::CreateMCSymbol(
      AuthPtrStubSym, AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
  MCOperand StubMCHi, StubMCLo;
 
  MCInstLowering.lowerOperand(StubMOHi, StubMCHi);
  MCInstLowering.lowerOperand(StubMOLo, StubMCLo);
 
  EmitToStreamer(
      *OutStreamer,
      MCInstBuilder(AArch64::ADRP).addReg(DstReg).addOperand(StubMCHi));
 
  EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRXui)
                                   .addReg(DstReg)
                                   .addReg(DstReg)
                                   .addOperand(StubMCLo));
}
 
void AArch64AsmPrinter::LowerMOVaddrPAC(const MachineInstr &MI) {
  const bool IsGOTLoad = MI.getOpcode() == AArch64::LOADgotPAC;
  const bool IsELFSignedGOT = MI.getParent()
                                  ->getParent()
                                  ->getInfo<AArch64FunctionInfo>()
                                  ->hasELFSignedGOT();
  MachineOperand GAOp = MI.getOperand(0);
  const uint64_t KeyC = MI.getOperand(1).getImm();
  assert(KeyC <= AArch64PACKey::LAST &&
         "key is out of range [0, AArch64PACKey::LAST]");
  const auto Key = (AArch64PACKey::ID)KeyC;
  const unsigned AddrDisc = MI.getOperand(2).getReg();
  const uint64_t Disc = MI.getOperand(3).getImm();
 
  const int64_t Offset = GAOp.getOffset();
  GAOp.setOffset(0);
 
  // Emit:
  // target materialization:
  // - via GOT:
  //   - unsigned GOT:
  //       adrp x16, :got:target
  //       ldr x16, [x16, :got_lo12:target]
  //       add offset to x16 if offset != 0
  //   - ELF signed GOT:
  //       adrp x17, :got:target
  //       add x17, x17, :got_auth_lo12:target
  //       ldr x16, [x17]
  //       aut{i|d}a x16, x17
  //       check+trap sequence (if no FPAC)
  //       add offset to x16 if offset != 0
  //
  // - direct:
  //     adrp x16, target
  //     add x16, x16, :lo12:target
  //     add offset to x16 if offset != 0
  //
  // add offset to x16:
  // - abs(offset) fits 24 bits:
  //     add/sub x16, x16, #<offset>[, #lsl 12] (up to 2 instructions)
  // - abs(offset) does not fit 24 bits:
  //   - offset < 0:
  //       movn+movk sequence filling x17 register with the offset (up to 4
  //       instructions)
  //       add x16, x16, x17
  //   - offset > 0:
  //       movz+movk sequence filling x17 register with the offset (up to 4
  //       instructions)
  //       add x16, x16, x17
  //
  // signing:
  // - 0 discriminator:
  //     paciza x16
  // - Non-0 discriminator, no address discriminator:
  //     mov x17, #Disc
  //     pacia x16, x17
  // - address discriminator (with potentially folded immediate discriminator):
  //     pacia x16, xAddrDisc
 
  MachineOperand GAMOHi(GAOp), GAMOLo(GAOp);
  MCOperand GAMCHi, GAMCLo;
 
  GAMOHi.setTargetFlags(AArch64II::MO_PAGE);
  GAMOLo.setTargetFlags(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
  if (IsGOTLoad) {
    GAMOHi.addTargetFlag(AArch64II::MO_GOT);
    GAMOLo.addTargetFlag(AArch64II::MO_GOT);
  }
 
  MCInstLowering.lowerOperand(GAMOHi, GAMCHi);
  MCInstLowering.lowerOperand(GAMOLo, GAMCLo);
 
  EmitToStreamer(
      MCInstBuilder(AArch64::ADRP)
          .addReg(IsGOTLoad && IsELFSignedGOT ? AArch64::X17 : AArch64::X16)
          .addOperand(GAMCHi));
 
  if (IsGOTLoad) {
    if (IsELFSignedGOT) {
      EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                         .addReg(AArch64::X17)
                         .addReg(AArch64::X17)
                         .addOperand(GAMCLo)
                         .addImm(0));
 
      EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                         .addReg(AArch64::X16)
                         .addReg(AArch64::X17)
                         .addImm(0));
 
      assert(GAOp.isGlobal());
      assert(GAOp.getGlobal()->getValueType() != nullptr);
 
      bool IsFunctionTy = GAOp.getGlobal()->getValueType()->isFunctionTy();
      auto AuthKey = IsFunctionTy ? AArch64PACKey::IA : AArch64PACKey::DA;
      emitAUT(AuthKey, AArch64::X16, AArch64::X17);
 
      if (!STI->hasFPAC())
        emitPtrauthCheckAuthenticatedValue(AArch64::X16, AArch64::X17, AuthKey,
                                           AArch64PAuth::AuthCheckMethod::XPAC);
    } else {
      EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                         .addReg(AArch64::X16)
                         .addReg(AArch64::X16)
                         .addOperand(GAMCLo));
    }
  } else {
    EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                       .addReg(AArch64::X16)
                       .addReg(AArch64::X16)
                       .addOperand(GAMCLo)
                       .addImm(0));
  }
 
  emitAddImm(AArch64::X16, Offset, AArch64::X17);
  Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, AArch64::X17);
 
  emitPAC(Key, AArch64::X16, DiscReg);
}
 
void AArch64AsmPrinter::LowerLOADgotAUTH(const MachineInstr &MI) {
  Register DstReg = MI.getOperand(0).getReg();
  Register AuthResultReg = STI->hasFPAC() ? DstReg : AArch64::X16;
  const MachineOperand &GAMO = MI.getOperand(1);
  assert(GAMO.getOffset() == 0);
 
  if (MI.getMF()->getTarget().getCodeModel() == CodeModel::Tiny) {
    MCOperand GAMC;
    MCInstLowering.lowerOperand(GAMO, GAMC);
    EmitToStreamer(
        MCInstBuilder(AArch64::ADR).addReg(AArch64::X17).addOperand(GAMC));
    EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                       .addReg(AuthResultReg)
                       .addReg(AArch64::X17)
                       .addImm(0));
  } else {
    MachineOperand GAHiOp(GAMO);
    MachineOperand GALoOp(GAMO);
    GAHiOp.addTargetFlag(AArch64II::MO_PAGE);
    GALoOp.addTargetFlag(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
 
    MCOperand GAMCHi, GAMCLo;
    MCInstLowering.lowerOperand(GAHiOp, GAMCHi);
    MCInstLowering.lowerOperand(GALoOp, GAMCLo);
 
    EmitToStreamer(
        MCInstBuilder(AArch64::ADRP).addReg(AArch64::X17).addOperand(GAMCHi));
 
    EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                       .addReg(AArch64::X17)
                       .addReg(AArch64::X17)
                       .addOperand(GAMCLo)
                       .addImm(0));
 
    EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                       .addReg(AuthResultReg)
                       .addReg(AArch64::X17)
                       .addImm(0));
  }
 
  assert(GAMO.isGlobal());
  MCSymbol *UndefWeakSym;
  if (GAMO.getGlobal()->hasExternalWeakLinkage()) {
    UndefWeakSym = createTempSymbol("undef_weak");
    EmitToStreamer(
        MCInstBuilder(AArch64::CBZX)
            .addReg(AuthResultReg)
            .addExpr(MCSymbolRefExpr::create(UndefWeakSym, OutContext)));
  }
 
  assert(GAMO.getGlobal()->getValueType() != nullptr);
 
  bool IsFunctionTy = GAMO.getGlobal()->getValueType()->isFunctionTy();
  auto AuthKey = IsFunctionTy ? AArch64PACKey::IA : AArch64PACKey::DA;
  emitAUT(AuthKey, AuthResultReg, AArch64::X17);
 
  if (GAMO.getGlobal()->hasExternalWeakLinkage())
    OutStreamer->emitLabel(UndefWeakSym);
 
  if (!STI->hasFPAC()) {
    emitPtrauthCheckAuthenticatedValue(AuthResultReg, AArch64::X17, AuthKey,
                                       AArch64PAuth::AuthCheckMethod::XPAC);
 
    emitMovXReg(DstReg, AuthResultReg);
  }
}
 
const MCExpr *
AArch64AsmPrinter::lowerBlockAddressConstant(const BlockAddress &BA) {
  const MCExpr *BAE = AsmPrinter::lowerBlockAddressConstant(BA);
  const Function &Fn = *BA.getFunction();
 
  if (std::optional<uint16_t> BADisc =
          STI->getPtrAuthBlockAddressDiscriminatorIfEnabled(Fn))
    return AArch64AuthMCExpr::create(BAE, *BADisc, AArch64PACKey::IA,
                                     /*HasAddressDiversity=*/false, OutContext);
 
  return BAE;
}
 
void AArch64AsmPrinter::emitCBPseudoExpansion(const MachineInstr *MI) {
  bool IsImm = false;
  unsigned Width = 0;
 
  switch (MI->getOpcode()) {
  default:
    llvm_unreachable("This is not a CB pseudo instruction");
  case AArch64::CBBAssertExt:
    IsImm = false;
    Width = 8;
    break;
  case AArch64::CBHAssertExt:
    IsImm = false;
    Width = 16;
    break;
  case AArch64::CBWPrr:
    Width = 32;
    break;
  case AArch64::CBXPrr:
    Width = 64;
    break;
  case AArch64::CBWPri:
    IsImm = true;
    Width = 32;
    break;
  case AArch64::CBXPri:
    IsImm = true;
    Width = 64;
    break;
  }
 
  AArch64CC::CondCode CC =
      static_cast<AArch64CC::CondCode>(MI->getOperand(0).getImm());
  bool NeedsRegSwap = false;
  bool NeedsImmDec = false;
  bool NeedsImmInc = false;
 
#define GET_CB_OPC(IsImm, Width, ImmCond, RegCond)                             \
  (IsImm                                                                       \
       ? (Width == 32 ? AArch64::CB##ImmCond##Wri : AArch64::CB##ImmCond##Xri) \
       : (Width == 8                                                           \
              ? AArch64::CBB##RegCond##Wrr                                     \
              : (Width == 16 ? AArch64::CBH##RegCond##Wrr                      \
                             : (Width == 32 ? AArch64::CB##RegCond##Wrr        \
                                            : AArch64::CB##RegCond##Xrr))))
  unsigned MCOpC;
 
  // Decide if we need to either swap register operands or increment/decrement
  // immediate operands
  switch (CC) {
  default:
    llvm_unreachable("Invalid CB condition code");
  case AArch64CC::EQ:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ EQ, /* Reg-Reg */ EQ);
    break;
  case AArch64CC::NE:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ NE, /* Reg-Reg */ NE);
    break;
  case AArch64CC::HS:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ HI, /* Reg-Reg */ HS);
    NeedsImmDec = IsImm;
    break;
  case AArch64CC::LO:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LO, /* Reg-Reg */ HI);
    NeedsRegSwap = !IsImm;
    break;
  case AArch64CC::HI:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ HI, /* Reg-Reg */ HI);
    break;
  case AArch64CC::LS:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LO, /* Reg-Reg */ HS);
    NeedsRegSwap = !IsImm;
    NeedsImmInc = IsImm;
    break;
  case AArch64CC::GE:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ GT, /* Reg-Reg */ GE);
    NeedsImmDec = IsImm;
    break;
  case AArch64CC::LT:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LT, /* Reg-Reg */ GT);
    NeedsRegSwap = !IsImm;
    break;
  case AArch64CC::GT:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ GT, /* Reg-Reg */ GT);
    break;
  case AArch64CC::LE:
    MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LT, /* Reg-Reg */ GE);
    NeedsRegSwap = !IsImm;
    NeedsImmInc = IsImm;
    break;
  }
#undef GET_CB_OPC
 
  MCInst Inst;
  Inst.setOpcode(MCOpC);
 
  MCOperand Lhs, Rhs, Trgt;
  lowerOperand(MI->getOperand(1), Lhs);
  lowerOperand(MI->getOperand(2), Rhs);
  lowerOperand(MI->getOperand(3), Trgt);
 
  // Now swap, increment or decrement
  if (NeedsRegSwap) {
    assert(Lhs.isReg() && "Expected register operand for CB");
    assert(Rhs.isReg() && "Expected register operand for CB");
    Inst.addOperand(Rhs);
    Inst.addOperand(Lhs);
  } else if (NeedsImmDec) {
    Rhs.setImm(Rhs.getImm() - 1);
    Inst.addOperand(Lhs);
    Inst.addOperand(Rhs);
  } else if (NeedsImmInc) {
    Rhs.setImm(Rhs.getImm() + 1);
    Inst.addOperand(Lhs);
    Inst.addOperand(Rhs);
  } else {
    Inst.addOperand(Lhs);
    Inst.addOperand(Rhs);
  }
 
  assert((!IsImm || (Rhs.getImm() >= 0 && Rhs.getImm() < 64)) &&
         "CB immediate operand out-of-bounds");
 
  Inst.addOperand(Trgt);
  EmitToStreamer(*OutStreamer, Inst);
}
 
// Simple pseudo-instructions have their lowering (with expansion to real
// instructions) auto-generated.
#include "AArch64GenMCPseudoLowering.inc"
 
void AArch64AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
  S.emitInstruction(Inst, *STI);
#ifndef NDEBUG
  ++InstsEmitted;
#endif
}
 
void AArch64AsmPrinter::emitInstruction(const MachineInstr *MI) {
  AArch64_MC::verifyInstructionPredicates(MI->getOpcode(), STI->getFeatureBits());
 
#ifndef NDEBUG
  InstsEmitted = 0;
  llvm::scope_exit CheckMISize([&]() {
    assert(STI->getInstrInfo()->getInstSizeInBytes(*MI) >= InstsEmitted * 4);
  });
#endif
 
  // Do any auto-generated pseudo lowerings.
  if (MCInst OutInst; lowerPseudoInstExpansion(MI, OutInst)) {
    EmitToStreamer(*OutStreamer, OutInst);
    return;
  }
 
  if (MI->getOpcode() == AArch64::ADRP) {
    for (auto &Opd : MI->operands()) {
      if (Opd.isSymbol() && StringRef(Opd.getSymbolName()) ==
                                "swift_async_extendedFramePointerFlags") {
        ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags = true;
      }
    }
  }
 
  if (AArch64FI->getLOHRelated().count(MI)) {
    // Generate a label for LOH related instruction
    MCSymbol *LOHLabel = createTempSymbol("loh");
    // Associate the instruction with the label
    LOHInstToLabel[MI] = LOHLabel;
    OutStreamer->emitLabel(LOHLabel);
  }
 
  AArch64TargetStreamer *TS =
    static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
  // Do any manual lowerings.
  switch (MI->getOpcode()) {
  default:
    assert(!AArch64InstrInfo::isTailCallReturnInst(*MI) &&
           "Unhandled tail call instruction");
    break;
  case AArch64::HINT: {
    // CurrentPatchableFunctionEntrySym can be CurrentFnBegin only for
    // -fpatchable-function-entry=N,0. The entry MBB is guaranteed to be
    // non-empty. If MI is the initial BTI, place the
    // __patchable_function_entries label after BTI.
    if (CurrentPatchableFunctionEntrySym &&
        CurrentPatchableFunctionEntrySym == CurrentFnBegin &&
        MI == &MF->front().front()) {
      int64_t Imm = MI->getOperand(0).getImm();
      if ((Imm & 32) && (Imm & 6)) {
        MCInst Inst;
        MCInstLowering.Lower(MI, Inst);
        EmitToStreamer(*OutStreamer, Inst);
        CurrentPatchableFunctionEntrySym = createTempSymbol("patch");
        OutStreamer->emitLabel(CurrentPatchableFunctionEntrySym);
        return;
      }
    }
    break;
  }
    case AArch64::MOVMCSym: {
      Register DestReg = MI->getOperand(0).getReg();
      const MachineOperand &MO_Sym = MI->getOperand(1);
      MachineOperand Hi_MOSym(MO_Sym), Lo_MOSym(MO_Sym);
      MCOperand Hi_MCSym, Lo_MCSym;
 
      Hi_MOSym.setTargetFlags(AArch64II::MO_G1 | AArch64II::MO_S);
      Lo_MOSym.setTargetFlags(AArch64II::MO_G0 | AArch64II::MO_NC);
 
      MCInstLowering.lowerOperand(Hi_MOSym, Hi_MCSym);
      MCInstLowering.lowerOperand(Lo_MOSym, Lo_MCSym);
 
      MCInst MovZ;
      MovZ.setOpcode(AArch64::MOVZXi);
      MovZ.addOperand(MCOperand::createReg(DestReg));
      MovZ.addOperand(Hi_MCSym);
      MovZ.addOperand(MCOperand::createImm(16));
      EmitToStreamer(*OutStreamer, MovZ);
 
      MCInst MovK;
      MovK.setOpcode(AArch64::MOVKXi);
      MovK.addOperand(MCOperand::createReg(DestReg));
      MovK.addOperand(MCOperand::createReg(DestReg));
      MovK.addOperand(Lo_MCSym);
      MovK.addOperand(MCOperand::createImm(0));
      EmitToStreamer(*OutStreamer, MovK);
      return;
  }
  case AArch64::MOVIv2d_ns:
    // It is generally beneficial to rewrite "fmov s0, wzr" to "movi d0, #0".
    // as movi is more efficient across all cores. Newer cores can eliminate
    // fmovs early and there is no difference with movi, but this not true for
    // all implementations.
    //
    // The floating-point version doesn't quite work in rare cases on older
    // CPUs, so on those targets we lower this instruction to movi.16b instead.
    if (STI->hasZeroCycleZeroingFPWorkaround() &&
        MI->getOperand(1).getImm() == 0) {
      MCInst TmpInst;
      TmpInst.setOpcode(AArch64::MOVIv16b_ns);
      TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
      TmpInst.addOperand(MCOperand::createImm(0));
      EmitToStreamer(*OutStreamer, TmpInst);
      return;
    }
    break;
 
  case AArch64::DBG_VALUE:
  case AArch64::DBG_VALUE_LIST:
    if (isVerbose() && OutStreamer->hasRawTextSupport()) {
      SmallString<128> TmpStr;
      raw_svector_ostream OS(TmpStr);
      PrintDebugValueComment(MI, OS);
      OutStreamer->emitRawText(StringRef(OS.str()));
    }
    return;
 
  case AArch64::EMITBKEY: {
      ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
      if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
          ExceptionHandlingType != ExceptionHandling::ARM)
        return;
 
      if (getFunctionCFISectionType(*MF) == CFISection::None)
        return;
 
      OutStreamer->emitCFIBKeyFrame();
      return;
  }
 
  case AArch64::EMITMTETAGGED: {
    ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
    if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
        ExceptionHandlingType != ExceptionHandling::ARM)
      return;
 
    if (getFunctionCFISectionType(*MF) != CFISection::None)
      OutStreamer->emitCFIMTETaggedFrame();
    return;
  }
 
  case AArch64::AUTx16x17: {
    const Register Pointer = AArch64::X16;
    const Register Scratch = AArch64::X17;
 
    PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(0).getImm(),
                             MI->getOperand(1).getImm(), MI->getOperand(2));
 
    emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, std::nullopt,
                          MI->getDeactivationSymbol());
    return;
  }
 
  case AArch64::AUTxMxN: {
    const Register Pointer = MI->getOperand(0).getReg();
    const Register Scratch = MI->getOperand(1).getReg();
 
    PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(3).getImm(),
                             MI->getOperand(4).getImm(), MI->getOperand(5));
 
    emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, std::nullopt,
                          MI->getDeactivationSymbol());
    return;
  }
 
  case AArch64::AUTPAC: {
    const Register Pointer = AArch64::X16;
    const Register Scratch = AArch64::X17;
 
    PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(0).getImm(),
                             MI->getOperand(1).getImm(), MI->getOperand(2));
 
    PtrAuthSchema SignSchema((AArch64PACKey::ID)MI->getOperand(3).getImm(),
                             MI->getOperand(4).getImm(), MI->getOperand(5));
 
    emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, SignSchema,
                          MI->getDeactivationSymbol());
    return;
  }
 
  case AArch64::PAC:
    emitPtrauthSign(MI);
    return;
 
  case AArch64::LOADauthptrstatic:
    LowerLOADauthptrstatic(*MI);
    return;
 
  case AArch64::LOADgotPAC:
  case AArch64::MOVaddrPAC:
    LowerMOVaddrPAC(*MI);
    return;
 
  case AArch64::LOADgotAUTH:
    LowerLOADgotAUTH(*MI);
    return;
 
  case AArch64::BRA:
  case AArch64::BLRA:
    emitPtrauthBranch(MI);
    return;
 
  // Tail calls use pseudo instructions so they have the proper code-gen
  // attributes (isCall, isReturn, etc.). We lower them to the real
  // instruction here.
  case AArch64::AUTH_TCRETURN:
  case AArch64::AUTH_TCRETURN_BTI: {
    Register Callee = MI->getOperand(0).getReg();
    const auto Key = (AArch64PACKey::ID)MI->getOperand(2).getImm();
    const uint64_t Disc = MI->getOperand(3).getImm();
 
    Register AddrDisc = MI->getOperand(4).getReg();
 
    Register ScratchReg = Callee == AArch64::X16 ? AArch64::X17 : AArch64::X16;
 
    emitPtrauthTailCallHardening(MI);
 
    // See the comments in emitPtrauthBranch.
    if (Callee == AddrDisc)
      report_fatal_error("Call target is signed with its own value");
 
    // After isX16X17Safer predicate was introduced, emitPtrauthDiscriminator is
    // no longer restricted to only reusing AddrDisc when it is X16 or X17
    // (which are implicit-def'ed by AUTH_TCRETURN pseudos), thus impose this
    // restriction manually not to clobber an unexpected register.
    bool AddrDiscIsImplicitDef =
        AddrDisc == AArch64::X16 || AddrDisc == AArch64::X17;
    Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, ScratchReg,
                                                AddrDiscIsImplicitDef);
    emitBLRA(/*IsCall*/ false, Key, Callee, DiscReg);
    return;
  }
 
  case AArch64::TCRETURNri:
  case AArch64::TCRETURNrix16x17:
  case AArch64::TCRETURNrix17:
  case AArch64::TCRETURNrinotx16:
  case AArch64::TCRETURNriALL: {
    emitPtrauthTailCallHardening(MI);
 
    recordIfImportCall(MI);
    MCInst TmpInst;
    TmpInst.setOpcode(AArch64::BR);
    TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
    EmitToStreamer(*OutStreamer, TmpInst);
    return;
  }
  case AArch64::TCRETURNdi: {
    emitPtrauthTailCallHardening(MI);
 
    MCOperand Dest;
    MCInstLowering.lowerOperand(MI->getOperand(0), Dest);
    recordIfImportCall(MI);
    MCInst TmpInst;
    TmpInst.setOpcode(AArch64::B);
    TmpInst.addOperand(Dest);
    EmitToStreamer(*OutStreamer, TmpInst);
    return;
  }
  case AArch64::SpeculationBarrierISBDSBEndBB: {
    // Print DSB SYS + ISB
    MCInst TmpInstDSB;
    TmpInstDSB.setOpcode(AArch64::DSB);
    TmpInstDSB.addOperand(MCOperand::createImm(0xf));
    EmitToStreamer(*OutStreamer, TmpInstDSB);
    MCInst TmpInstISB;
    TmpInstISB.setOpcode(AArch64::ISB);
    TmpInstISB.addOperand(MCOperand::createImm(0xf));
    EmitToStreamer(*OutStreamer, TmpInstISB);
    return;
  }
  case AArch64::SpeculationBarrierSBEndBB: {
    // Print SB
    MCInst TmpInstSB;
    TmpInstSB.setOpcode(AArch64::SB);
    EmitToStreamer(*OutStreamer, TmpInstSB);
    return;
  }
  case AArch64::TLSDESC_AUTH_CALLSEQ: {
    /// lower this to:
    ///    adrp  x0, :tlsdesc_auth:var
    ///    ldr   x16, [x0, #:tlsdesc_auth_lo12:var]
    ///    add   x0, x0, #:tlsdesc_auth_lo12:var
    ///    blraa x16, x0
    ///    (TPIDR_EL0 offset now in x0)
    const MachineOperand &MO_Sym = MI->getOperand(0);
    MachineOperand MO_TLSDESC_LO12(MO_Sym), MO_TLSDESC(MO_Sym);
    MCOperand SymTLSDescLo12, SymTLSDesc;
    MO_TLSDESC_LO12.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGEOFF);
    MO_TLSDESC.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGE);
    MCInstLowering.lowerOperand(MO_TLSDESC_LO12, SymTLSDescLo12);
    MCInstLowering.lowerOperand(MO_TLSDESC, SymTLSDesc);
 
    MCInst Adrp;
    Adrp.setOpcode(AArch64::ADRP);
    Adrp.addOperand(MCOperand::createReg(AArch64::X0));
    Adrp.addOperand(SymTLSDesc);
    EmitToStreamer(*OutStreamer, Adrp);
 
    MCInst Ldr;
    Ldr.setOpcode(AArch64::LDRXui);
    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
    Ldr.addOperand(MCOperand::createReg(AArch64::X0));
    Ldr.addOperand(SymTLSDescLo12);
    Ldr.addOperand(MCOperand::createImm(0));
    EmitToStreamer(*OutStreamer, Ldr);
 
    MCInst Add;
    Add.setOpcode(AArch64::ADDXri);
    Add.addOperand(MCOperand::createReg(AArch64::X0));
    Add.addOperand(MCOperand::createReg(AArch64::X0));
    Add.addOperand(SymTLSDescLo12);
    Add.addOperand(MCOperand::createImm(AArch64_AM::getShiftValue(0)));
    EmitToStreamer(*OutStreamer, Add);
 
    // Authenticated TLSDESC accesses are not relaxed.
    // Thus, do not emit .tlsdesccall for AUTH TLSDESC.
 
    MCInst Blraa;
    Blraa.setOpcode(AArch64::BLRAA);
    Blraa.addOperand(MCOperand::createReg(AArch64::X16));
    Blraa.addOperand(MCOperand::createReg(AArch64::X0));
    EmitToStreamer(*OutStreamer, Blraa);
 
    return;
  }
  case AArch64::TLSDESC_CALLSEQ: {
    /// lower this to:
    ///    adrp  x0, :tlsdesc:var
    ///    ldr   x1, [x0, #:tlsdesc_lo12:var]
    ///    add   x0, x0, #:tlsdesc_lo12:var
    ///    .tlsdesccall var
    ///    blr   x1
    ///    (TPIDR_EL0 offset now in x0)
    const MachineOperand &MO_Sym = MI->getOperand(0);
    MachineOperand MO_TLSDESC_LO12(MO_Sym), MO_TLSDESC(MO_Sym);
    MCOperand Sym, SymTLSDescLo12, SymTLSDesc;
    MO_TLSDESC_LO12.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGEOFF);
    MO_TLSDESC.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGE);
    MCInstLowering.lowerOperand(MO_Sym, Sym);
    MCInstLowering.lowerOperand(MO_TLSDESC_LO12, SymTLSDescLo12);
    MCInstLowering.lowerOperand(MO_TLSDESC, SymTLSDesc);
 
    MCInst Adrp;
    Adrp.setOpcode(AArch64::ADRP);
    Adrp.addOperand(MCOperand::createReg(AArch64::X0));
    Adrp.addOperand(SymTLSDesc);
    EmitToStreamer(*OutStreamer, Adrp);
 
    MCInst Ldr;
    if (STI->isTargetILP32()) {
      Ldr.setOpcode(AArch64::LDRWui);
      Ldr.addOperand(MCOperand::createReg(AArch64::W1));
    } else {
      Ldr.setOpcode(AArch64::LDRXui);
      Ldr.addOperand(MCOperand::createReg(AArch64::X1));
    }
    Ldr.addOperand(MCOperand::createReg(AArch64::X0));
    Ldr.addOperand(SymTLSDescLo12);
    Ldr.addOperand(MCOperand::createImm(0));
    EmitToStreamer(*OutStreamer, Ldr);
 
    MCInst Add;
    if (STI->isTargetILP32()) {
      Add.setOpcode(AArch64::ADDWri);
      Add.addOperand(MCOperand::createReg(AArch64::W0));
      Add.addOperand(MCOperand::createReg(AArch64::W0));
    } else {
      Add.setOpcode(AArch64::ADDXri);
      Add.addOperand(MCOperand::createReg(AArch64::X0));
      Add.addOperand(MCOperand::createReg(AArch64::X0));
    }
    Add.addOperand(SymTLSDescLo12);
    Add.addOperand(MCOperand::createImm(AArch64_AM::getShiftValue(0)));
    EmitToStreamer(*OutStreamer, Add);
 
    // Emit a relocation-annotation. This expands to no code, but requests
    // the following instruction gets an R_AARCH64_TLSDESC_CALL.
    MCInst TLSDescCall;
    TLSDescCall.setOpcode(AArch64::TLSDESCCALL);
    TLSDescCall.addOperand(Sym);
    EmitToStreamer(*OutStreamer, TLSDescCall);
#ifndef NDEBUG
    --InstsEmitted; // no code emitted
#endif
 
    MCInst Blr;
    Blr.setOpcode(AArch64::BLR);
    Blr.addOperand(MCOperand::createReg(AArch64::X1));
    EmitToStreamer(*OutStreamer, Blr);
 
    return;
  }
 
  case AArch64::JumpTableDest32:
  case AArch64::JumpTableDest16:
  case AArch64::JumpTableDest8:
    LowerJumpTableDest(*OutStreamer, *MI);
    return;
 
  case AArch64::BR_JumpTable:
    LowerHardenedBRJumpTable(*MI);
    return;
 
  case AArch64::FMOVH0:
  case AArch64::FMOVS0:
  case AArch64::FMOVD0:
    emitFMov0(*MI);
    return;
 
  case AArch64::MOPSMemoryCopyPseudo:
  case AArch64::MOPSMemoryMovePseudo:
  case AArch64::MOPSMemorySetPseudo:
  case AArch64::MOPSMemorySetTaggingPseudo:
    LowerMOPS(*OutStreamer, *MI);
    return;
 
  case TargetOpcode::STACKMAP:
    return LowerSTACKMAP(*OutStreamer, SM, *MI);
 
  case TargetOpcode::PATCHPOINT:
    return LowerPATCHPOINT(*OutStreamer, SM, *MI);
 
  case TargetOpcode::STATEPOINT:
    return LowerSTATEPOINT(*OutStreamer, SM, *MI);
 
  case TargetOpcode::FAULTING_OP:
    return LowerFAULTING_OP(*MI);
 
  case TargetOpcode::PATCHABLE_FUNCTION_ENTER:
    LowerPATCHABLE_FUNCTION_ENTER(*MI);
    return;
 
  case TargetOpcode::PATCHABLE_FUNCTION_EXIT:
    LowerPATCHABLE_FUNCTION_EXIT(*MI);
    return;
 
  case TargetOpcode::PATCHABLE_TAIL_CALL:
    LowerPATCHABLE_TAIL_CALL(*MI);
    return;
  case TargetOpcode::PATCHABLE_EVENT_CALL:
    return LowerPATCHABLE_EVENT_CALL(*MI, false);
  case TargetOpcode::PATCHABLE_TYPED_EVENT_CALL:
    return LowerPATCHABLE_EVENT_CALL(*MI, true);
 
  case AArch64::KCFI_CHECK:
    LowerKCFI_CHECK(*MI);
    return;
 
  case AArch64::HWASAN_CHECK_MEMACCESS:
  case AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES:
  case AArch64::HWASAN_CHECK_MEMACCESS_FIXEDSHADOW:
  case AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW:
    LowerHWASAN_CHECK_MEMACCESS(*MI);
    return;
 
  case AArch64::SEH_StackAlloc:
    TS->emitARM64WinCFIAllocStack(MI->getOperand(0).getImm());
    return;
 
  case AArch64::SEH_SaveFPLR:
    TS->emitARM64WinCFISaveFPLR(MI->getOperand(0).getImm());
    return;
 
  case AArch64::SEH_SaveFPLR_X:
    assert(MI->getOperand(0).getImm() < 0 &&
           "Pre increment SEH opcode must have a negative offset");
    TS->emitARM64WinCFISaveFPLRX(-MI->getOperand(0).getImm());
    return;
 
  case AArch64::SEH_SaveReg:
    TS->emitARM64WinCFISaveReg(MI->getOperand(0).getImm(),
                               MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SaveReg_X:
    assert(MI->getOperand(1).getImm() < 0 &&
           "Pre increment SEH opcode must have a negative offset");
    TS->emitARM64WinCFISaveRegX(MI->getOperand(0).getImm(),
                                -MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SaveRegP:
    if (MI->getOperand(1).getImm() == 30 && MI->getOperand(0).getImm() >= 19 &&
        MI->getOperand(0).getImm() <= 28) {
      assert((MI->getOperand(0).getImm() - 19) % 2 == 0 &&
             "Register paired with LR must be odd");
      TS->emitARM64WinCFISaveLRPair(MI->getOperand(0).getImm(),
                                    MI->getOperand(2).getImm());
      return;
    }
    assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
            "Non-consecutive registers not allowed for save_regp");
    TS->emitARM64WinCFISaveRegP(MI->getOperand(0).getImm(),
                                MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SaveRegP_X:
    assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
            "Non-consecutive registers not allowed for save_regp_x");
    assert(MI->getOperand(2).getImm() < 0 &&
           "Pre increment SEH opcode must have a negative offset");
    TS->emitARM64WinCFISaveRegPX(MI->getOperand(0).getImm(),
                                 -MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SaveFReg:
    TS->emitARM64WinCFISaveFReg(MI->getOperand(0).getImm(),
                                MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SaveFReg_X:
    assert(MI->getOperand(1).getImm() < 0 &&
           "Pre increment SEH opcode must have a negative offset");
    TS->emitARM64WinCFISaveFRegX(MI->getOperand(0).getImm(),
                                 -MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SaveFRegP:
    assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
            "Non-consecutive registers not allowed for save_regp");
    TS->emitARM64WinCFISaveFRegP(MI->getOperand(0).getImm(),
                                 MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SaveFRegP_X:
    assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
            "Non-consecutive registers not allowed for save_regp_x");
    assert(MI->getOperand(2).getImm() < 0 &&
           "Pre increment SEH opcode must have a negative offset");
    TS->emitARM64WinCFISaveFRegPX(MI->getOperand(0).getImm(),
                                  -MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SetFP:
    TS->emitARM64WinCFISetFP();
    return;
 
  case AArch64::SEH_AddFP:
    TS->emitARM64WinCFIAddFP(MI->getOperand(0).getImm());
    return;
 
  case AArch64::SEH_Nop:
    TS->emitARM64WinCFINop();
    return;
 
  case AArch64::SEH_PrologEnd:
    TS->emitARM64WinCFIPrologEnd();
    return;
 
  case AArch64::SEH_EpilogStart:
    TS->emitARM64WinCFIEpilogStart();
    return;
 
  case AArch64::SEH_EpilogEnd:
    TS->emitARM64WinCFIEpilogEnd();
    return;
 
  case AArch64::SEH_PACSignLR:
    TS->emitARM64WinCFIPACSignLR();
    return;
 
  case AArch64::SEH_SaveAnyRegI:
    assert(MI->getOperand(1).getImm() <= 1008 &&
           "SaveAnyRegQP SEH opcode offset must fit into 6 bits");
    TS->emitARM64WinCFISaveAnyRegI(MI->getOperand(0).getImm(),
                                   MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SaveAnyRegIP:
    assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
           "Non-consecutive registers not allowed for save_any_reg");
    assert(MI->getOperand(2).getImm() <= 1008 &&
           "SaveAnyRegQP SEH opcode offset must fit into 6 bits");
    TS->emitARM64WinCFISaveAnyRegIP(MI->getOperand(0).getImm(),
                                    MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SaveAnyRegQP:
    assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
           "Non-consecutive registers not allowed for save_any_reg");
    assert(MI->getOperand(2).getImm() >= 0 &&
           "SaveAnyRegQP SEH opcode offset must be non-negative");
    assert(MI->getOperand(2).getImm() <= 1008 &&
           "SaveAnyRegQP SEH opcode offset must fit into 6 bits");
    TS->emitARM64WinCFISaveAnyRegQP(MI->getOperand(0).getImm(),
                                    MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_SaveAnyRegQPX:
    assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
           "Non-consecutive registers not allowed for save_any_reg");
    assert(MI->getOperand(2).getImm() < 0 &&
           "SaveAnyRegQPX SEH opcode offset must be negative");
    assert(MI->getOperand(2).getImm() >= -1008 &&
           "SaveAnyRegQPX SEH opcode offset must fit into 6 bits");
    TS->emitARM64WinCFISaveAnyRegQPX(MI->getOperand(0).getImm(),
                                     -MI->getOperand(2).getImm());
    return;
 
  case AArch64::SEH_AllocZ:
    assert(MI->getOperand(0).getImm() >= 0 &&
           "AllocZ SEH opcode offset must be non-negative");
    assert(MI->getOperand(0).getImm() <= 255 &&
           "AllocZ SEH opcode offset must fit into 8 bits");
    TS->emitARM64WinCFIAllocZ(MI->getOperand(0).getImm());
    return;
 
  case AArch64::SEH_SaveZReg:
    assert(MI->getOperand(1).getImm() >= 0 &&
           "SaveZReg SEH opcode offset must be non-negative");
    assert(MI->getOperand(1).getImm() <= 255 &&
           "SaveZReg SEH opcode offset must fit into 8 bits");
    TS->emitARM64WinCFISaveZReg(MI->getOperand(0).getImm(),
                                MI->getOperand(1).getImm());
    return;
 
  case AArch64::SEH_SavePReg:
    assert(MI->getOperand(1).getImm() >= 0 &&
           "SavePReg SEH opcode offset must be non-negative");
    assert(MI->getOperand(1).getImm() <= 255 &&
           "SavePReg SEH opcode offset must fit into 8 bits");
    TS->emitARM64WinCFISavePReg(MI->getOperand(0).getImm(),
                                MI->getOperand(1).getImm());
    return;
 
  case AArch64::BLR:
  case AArch64::BR: {
    recordIfImportCall(MI);
    MCInst TmpInst;
    MCInstLowering.Lower(MI, TmpInst);
    EmitToStreamer(*OutStreamer, TmpInst);
    return;
  }
  case AArch64::CBWPri:
  case AArch64::CBXPri:
  case AArch64::CBBAssertExt:
  case AArch64::CBHAssertExt:
  case AArch64::CBWPrr:
  case AArch64::CBXPrr:
    emitCBPseudoExpansion(MI);
    return;
  }
 
  if (emitDeactivationSymbolRelocation(MI->getDeactivationSymbol()))
    return;
 
  // Finally, do the automated lowerings for everything else.
  MCInst TmpInst;
  MCInstLowering.Lower(MI, TmpInst);
  EmitToStreamer(*OutStreamer, TmpInst);
}
 
void AArch64AsmPrinter::recordIfImportCall(
    const llvm::MachineInstr *BranchInst) {
  if (!EnableImportCallOptimization)
    return;
 
  auto [GV, OpFlags] = BranchInst->getMF()->tryGetCalledGlobal(BranchInst);
  if (GV && GV->hasDLLImportStorageClass()) {
    auto *CallSiteSymbol = MMI->getContext().createNamedTempSymbol("impcall");
    OutStreamer->emitLabel(CallSiteSymbol);
 
    auto *CalledSymbol = MCInstLowering.GetGlobalValueSymbol(GV, OpFlags);
    SectionToImportedFunctionCalls[OutStreamer->getCurrentSectionOnly()]
        .push_back({CallSiteSymbol, CalledSymbol});
  }
}
 
void AArch64AsmPrinter::emitMachOIFuncStubBody(Module &M, const GlobalIFunc &GI,
                                               MCSymbol *LazyPointer) {
  // _ifunc:
  //   adrp    x16, lazy_pointer@GOTPAGE
  //   ldr     x16, [x16, lazy_pointer@GOTPAGEOFF]
  //   ldr     x16, [x16]
  //   br      x16
 
  {
    MCInst Adrp;
    Adrp.setOpcode(AArch64::ADRP);
    Adrp.addOperand(MCOperand::createReg(AArch64::X16));
    MCOperand SymPage;
    MCInstLowering.lowerOperand(
        MachineOperand::CreateMCSymbol(LazyPointer,
                                       AArch64II::MO_GOT | AArch64II::MO_PAGE),
        SymPage);
    Adrp.addOperand(SymPage);
    EmitToStreamer(Adrp);
  }
 
  {
    MCInst Ldr;
    Ldr.setOpcode(AArch64::LDRXui);
    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
    MCOperand SymPageOff;
    MCInstLowering.lowerOperand(
        MachineOperand::CreateMCSymbol(LazyPointer, AArch64II::MO_GOT |
                                                        AArch64II::MO_PAGEOFF),
        SymPageOff);
    Ldr.addOperand(SymPageOff);
    Ldr.addOperand(MCOperand::createImm(0));
    EmitToStreamer(Ldr);
  }
 
  EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
                     .addReg(AArch64::X16)
                     .addReg(AArch64::X16)
                     .addImm(0));
 
  EmitToStreamer(MCInstBuilder(TM.getTargetTriple().isArm64e() ? AArch64::BRAAZ
                                                               : AArch64::BR)
                     .addReg(AArch64::X16));
}
 
void AArch64AsmPrinter::emitMachOIFuncStubHelperBody(Module &M,
                                                     const GlobalIFunc &GI,
                                                     MCSymbol *LazyPointer) {
  // These stub helpers are only ever called once, so here we're optimizing for
  // minimum size by using the pre-indexed store variants, which saves a few
  // bytes of instructions to bump & restore sp.
 
  // _ifunc.stub_helper:
  //   stp  fp, lr, [sp, #-16]!
  //   mov  fp, sp
  //   stp  x1, x0, [sp, #-16]!
  //   stp  x3, x2, [sp, #-16]!
  //   stp  x5, x4, [sp, #-16]!
  //   stp  x7, x6, [sp, #-16]!
  //   stp  d1, d0, [sp, #-16]!
  //   stp  d3, d2, [sp, #-16]!
  //   stp  d5, d4, [sp, #-16]!
  //   stp  d7, d6, [sp, #-16]!
  //   bl _resolver
  //   adrp x16, lazy_pointer@GOTPAGE
  //   ldr  x16, [x16, lazy_pointer@GOTPAGEOFF]
  //   str  x0, [x16]
  //   mov  x16, x0
  //   ldp  d7, d6, [sp], #16
  //   ldp  d5, d4, [sp], #16
  //   ldp  d3, d2, [sp], #16
  //   ldp  d1, d0, [sp], #16
  //   ldp  x7, x6, [sp], #16
  //   ldp  x5, x4, [sp], #16
  //   ldp  x3, x2, [sp], #16
  //   ldp  x1, x0, [sp], #16
  //   ldp  fp, lr, [sp], #16
  //   br x16
 
  EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
                     .addReg(AArch64::SP)
                     .addReg(AArch64::FP)
                     .addReg(AArch64::LR)
                     .addReg(AArch64::SP)
                     .addImm(-2));
 
  EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                     .addReg(AArch64::FP)
                     .addReg(AArch64::SP)
                     .addImm(0)
                     .addImm(0));
 
  for (int I = 0; I != 4; ++I)
    EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
                       .addReg(AArch64::SP)
                       .addReg(AArch64::X1 + 2 * I)
                       .addReg(AArch64::X0 + 2 * I)
                       .addReg(AArch64::SP)
                       .addImm(-2));
 
  for (int I = 0; I != 4; ++I)
    EmitToStreamer(MCInstBuilder(AArch64::STPDpre)
                       .addReg(AArch64::SP)
                       .addReg(AArch64::D1 + 2 * I)
                       .addReg(AArch64::D0 + 2 * I)
                       .addReg(AArch64::SP)
                       .addImm(-2));
 
  EmitToStreamer(
      MCInstBuilder(AArch64::BL)
          .addOperand(MCOperand::createExpr(lowerConstant(GI.getResolver()))));
 
  {
    MCInst Adrp;
    Adrp.setOpcode(AArch64::ADRP);
    Adrp.addOperand(MCOperand::createReg(AArch64::X16));
    MCOperand SymPage;
    MCInstLowering.lowerOperand(
        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
                                 AArch64II::MO_GOT | AArch64II::MO_PAGE),
        SymPage);
    Adrp.addOperand(SymPage);
    EmitToStreamer(Adrp);
  }
 
  {
    MCInst Ldr;
    Ldr.setOpcode(AArch64::LDRXui);
    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
    MCOperand SymPageOff;
    MCInstLowering.lowerOperand(
        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
                                 AArch64II::MO_GOT | AArch64II::MO_PAGEOFF),
        SymPageOff);
    Ldr.addOperand(SymPageOff);
    Ldr.addOperand(MCOperand::createImm(0));
    EmitToStreamer(Ldr);
  }
 
  EmitToStreamer(MCInstBuilder(AArch64::STRXui)
                     .addReg(AArch64::X0)
                     .addReg(AArch64::X16)
                     .addImm(0));
 
  EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
                     .addReg(AArch64::X16)
                     .addReg(AArch64::X0)
                     .addImm(0)
                     .addImm(0));
 
  for (int I = 3; I != -1; --I)
    EmitToStreamer(MCInstBuilder(AArch64::LDPDpost)
                       .addReg(AArch64::SP)
                       .addReg(AArch64::D1 + 2 * I)
                       .addReg(AArch64::D0 + 2 * I)
                       .addReg(AArch64::SP)
                       .addImm(2));
 
  for (int I = 3; I != -1; --I)
    EmitToStreamer(MCInstBuilder(AArch64::LDPXpost)
                       .addReg(AArch64::SP)
                       .addReg(AArch64::X1 + 2 * I)
                       .addReg(AArch64::X0 + 2 * I)
                       .addReg(AArch64::SP)
                       .addImm(2));
 
  EmitToStreamer(MCInstBuilder(AArch64::LDPXpost)
                     .addReg(AArch64::SP)
                     .addReg(AArch64::FP)
                     .addReg(AArch64::LR)
                     .addReg(AArch64::SP)
                     .addImm(2));
 
  EmitToStreamer(MCInstBuilder(TM.getTargetTriple().isArm64e() ? AArch64::BRAAZ
                                                               : AArch64::BR)
                     .addReg(AArch64::X16));
}
 
const MCExpr *AArch64AsmPrinter::lowerConstant(const Constant *CV,
                                               const Constant *BaseCV,
                                               uint64_t Offset) {
  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) {
    return MCSymbolRefExpr::create(MCInstLowering.GetGlobalValueSymbol(GV, 0),
                                   OutContext);
  }
 
  return AsmPrinter::lowerConstant(CV, BaseCV, Offset);
}
 
char AArch64AsmPrinter::ID = 0;
 
INITIALIZE_PASS(AArch64AsmPrinter, "aarch64-asm-printer",
                "AArch64 Assembly Printer", false, false)
 
// Force static initialization.
extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
LLVMInitializeAArch64AsmPrinter() {
  RegisterAsmPrinter<AArch64AsmPrinter> X(getTheAArch64leTarget());
  RegisterAsmPrinter<AArch64AsmPrinter> Y(getTheAArch64beTarget());
  RegisterAsmPrinter<AArch64AsmPrinter> Z(getTheARM64Target());
  RegisterAsmPrinter<AArch64AsmPrinter> W(getTheARM64_32Target());
  RegisterAsmPrinter<AArch64AsmPrinter> V(getTheAArch64_32Target());
}