[llvm] Revert "[PAC][AArch64] Lower ptrauth constants in code (#94241)" (PR #96865)

via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 27 01:10:58 PDT 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-selectiondag

@llvm/pr-subscribers-backend-aarch64

Author: Daniil Kovalev (kovdan01)

<details>
<summary>Changes</summary>

This reverts #<!-- -->94241.

See buildbot failure https://lab.llvm.org/buildbot/#/builders/51/builds/570

---

Patch is 74.98 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/96865.diff


27 Files Affected:

- (modified) llvm/docs/GlobalISel/GenericOpcode.rst (-11) 
- (modified) llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h (-7) 
- (modified) llvm/include/llvm/CodeGen/ISDOpcodes.h (-6) 
- (modified) llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h (-20) 
- (modified) llvm/include/llvm/Support/TargetOpcodes.def (-3) 
- (modified) llvm/include/llvm/Target/GenericOpcodes.td (-6) 
- (modified) llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp (+1-5) 
- (modified) llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp (-13) 
- (modified) llvm/lib/CodeGen/MachineModuleInfoImpls.cpp (-23) 
- (modified) llvm/lib/CodeGen/MachineVerifier.cpp (-6) 
- (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (-7) 
- (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp (+2-2) 
- (modified) llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp (-252) 
- (modified) llvm/lib/Target/AArch64/AArch64ISelLowering.cpp (-131) 
- (modified) llvm/lib/Target/AArch64/AArch64ISelLowering.h (-6) 
- (modified) llvm/lib/Target/AArch64/AArch64InstrInfo.td (-32) 
- (modified) llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp (-37) 
- (modified) llvm/lib/Target/AArch64/AArch64TargetObjectFile.h (-6) 
- (modified) llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp (-144) 
- (modified) llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp (-3) 
- (modified) llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir (-4) 
- (removed) llvm/test/CodeGen/AArch64/GlobalISel/ptrauth-constant-in-code.ll (-235) 
- (removed) llvm/test/CodeGen/AArch64/ptrauth-constant-in-code.ll (-230) 
- (modified) llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td (+1-1) 
- (modified) llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-variadics.td (+1-1) 
- (modified) llvm/test/TableGen/GlobalISelCombinerEmitter/match-table.td (+31-31) 
- (modified) llvm/test/TableGen/GlobalISelEmitter.td (+1-1) 


``````````diff
diff --git a/llvm/docs/GlobalISel/GenericOpcode.rst b/llvm/docs/GlobalISel/GenericOpcode.rst
index b05394aeee003..42f56348885b4 100644
--- a/llvm/docs/GlobalISel/GenericOpcode.rst
+++ b/llvm/docs/GlobalISel/GenericOpcode.rst
@@ -60,17 +60,6 @@ The address of a global value.
 
   %0(p0) = G_GLOBAL_VALUE @var_local
 
-G_PTRAUTH_GLOBAL_VALUE
-^^^^^^^^^^^^^^^^^^^^^^
-
-The signed address of a global value. Operands: address to be signed (pointer),
-key (32-bit imm), address for address discrimination (zero if not needed) and
-an extra discriminator (64-bit imm).
-
-.. code-block:: none
-
-  %0:_(p0) = G_PTRAUTH_GLOBAL_VALUE %1:_(p0), s32, %2:_(p0), s64
-
 G_BLOCK_ADDR
 ^^^^^^^^^^^^
 
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h b/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
index 954511eb731fa..a95ed3109feb8 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
@@ -886,13 +886,6 @@ class MachineIRBuilder {
   MachineInstrBuilder buildFConstant(const DstOp &Res, double Val);
   MachineInstrBuilder buildFConstant(const DstOp &Res, const APFloat &Val);
 
-  /// Build and insert G_PTRAUTH_GLOBAL_VALUE
-  ///
-  /// \return a MachineInstrBuilder for the newly created instruction.
-  MachineInstrBuilder buildConstantPtrAuth(const DstOp &Res,
-                                           const ConstantPtrAuth *CPA,
-                                           Register Addr, Register AddrDisc);
-
   /// Build and insert \p Res = COPY Op
   ///
   /// Register-to-register COPY sets \p Res to \p Op.
diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 88e3339e2453f..6bb89fb58a296 100644
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -83,12 +83,6 @@ enum NodeType {
   ExternalSymbol,
   BlockAddress,
 
-  /// A ptrauth constant.
-  /// ptr, key, addr-disc, disc
-  /// Note that the addr-disc can be a non-constant value, to allow representing
-  /// a constant global address signed using address-diversification, in code.
-  PtrAuthGlobalAddress,
-
   /// The address of the GOT
   GLOBAL_OFFSET_TABLE,
 
diff --git a/llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h b/llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h
index 64d841d86c7c4..f8a328f13eded 100644
--- a/llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h
+++ b/llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h
@@ -61,20 +61,10 @@ class MachineModuleInfoMachO : public MachineModuleInfoImpl {
 /// MachineModuleInfoELF - This is a MachineModuleInfoImpl implementation
 /// for ELF targets.
 class MachineModuleInfoELF : public MachineModuleInfoImpl {
-public:
-  struct AuthStubInfo {
-    const MCExpr *AuthPtrRef;
-  };
-
-private:
   /// GVStubs - These stubs are used to materialize global addresses in PIC
   /// mode.
   DenseMap<MCSymbol *, StubValueTy> GVStubs;
 
-  /// AuthPtrStubs - These stubs are used to materialize signed addresses for
-  /// extern_weak symbols.
-  DenseMap<MCSymbol *, AuthStubInfo> AuthPtrStubs;
-
   virtual void anchor(); // Out of line virtual method.
 
 public:
@@ -85,19 +75,9 @@ class MachineModuleInfoELF : public MachineModuleInfoImpl {
     return GVStubs[Sym];
   }
 
-  AuthStubInfo &getAuthPtrStubEntry(MCSymbol *Sym) {
-    assert(Sym && "Key cannot be null");
-    return AuthPtrStubs[Sym];
-  }
-
   /// Accessor methods to return the set of stubs in sorted order.
 
   SymbolListTy GetGVStubList() { return getSortedStubs(GVStubs); }
-
-  using AuthStubPairTy = std::pair<MCSymbol *, AuthStubInfo>;
-  typedef std::vector<AuthStubPairTy> AuthStubListTy;
-
-  AuthStubListTy getAuthGVStubList();
 };
 
 /// MachineModuleInfoCOFF - This is a MachineModuleInfoImpl implementation
diff --git a/llvm/include/llvm/Support/TargetOpcodes.def b/llvm/include/llvm/Support/TargetOpcodes.def
index e7f40e87ed24a..df4b264af72a8 100644
--- a/llvm/include/llvm/Support/TargetOpcodes.def
+++ b/llvm/include/llvm/Support/TargetOpcodes.def
@@ -294,9 +294,6 @@ HANDLE_TARGET_OPCODE(G_FRAME_INDEX)
 /// Generic reference to global value.
 HANDLE_TARGET_OPCODE(G_GLOBAL_VALUE)
 
-/// Generic ptrauth-signed reference to global value.
-HANDLE_TARGET_OPCODE(G_PTRAUTH_GLOBAL_VALUE)
-
 /// Generic instruction to materialize the address of an object in the constant
 /// pool.
 HANDLE_TARGET_OPCODE(G_CONSTANT_POOL)
diff --git a/llvm/include/llvm/Target/GenericOpcodes.td b/llvm/include/llvm/Target/GenericOpcodes.td
index e1710ff2d8abf..4abffe6476c85 100644
--- a/llvm/include/llvm/Target/GenericOpcodes.td
+++ b/llvm/include/llvm/Target/GenericOpcodes.td
@@ -110,12 +110,6 @@ def G_GLOBAL_VALUE : GenericInstruction {
   let hasSideEffects = false;
 }
 
-def G_PTRAUTH_GLOBAL_VALUE : GenericInstruction {
-  let OutOperandList = (outs type0:$dst);
-  let InOperandList = (ins unknown:$addr, i32imm:$key, type1:$addrdisc, i64imm:$disc);
-  let hasSideEffects = 0;
-}
-
 def G_CONSTANT_POOL : GenericInstruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins unknown:$src);
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index c9986dfede1a1..ddf6d3c20f022 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -3494,11 +3494,7 @@ bool IRTranslator::translate(const Constant &C, Register Reg) {
     EntryBuilder->buildConstant(Reg, 0);
   else if (auto GV = dyn_cast<GlobalValue>(&C))
     EntryBuilder->buildGlobalValue(Reg, GV);
-  else if (auto CPA = dyn_cast<ConstantPtrAuth>(&C)) {
-    Register Addr = getOrCreateVReg(*CPA->getPointer());
-    Register AddrDisc = getOrCreateVReg(*CPA->getAddrDiscriminator());
-    EntryBuilder->buildConstantPtrAuth(Reg, CPA, Addr, AddrDisc);
-  } else if (auto CAZ = dyn_cast<ConstantAggregateZero>(&C)) {
+  else if (auto CAZ = dyn_cast<ConstantAggregateZero>(&C)) {
     if (!isa<FixedVectorType>(CAZ->getType()))
       return false;
     // Return the scalar if it is a <1 x Ty> vector.
diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 06a6c1f93ef1f..37aa4e0aed7e8 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -397,19 +397,6 @@ MachineInstrBuilder MachineIRBuilder::buildFConstant(const DstOp &Res,
   return buildFConstant(Res, *CFP);
 }
 
-MachineInstrBuilder
-MachineIRBuilder::buildConstantPtrAuth(const DstOp &Res,
-                                       const ConstantPtrAuth *CPA,
-                                       Register Addr, Register AddrDisc) {
-  auto MIB = buildInstr(TargetOpcode::G_PTRAUTH_GLOBAL_VALUE);
-  Res.addDefToMIB(*getMRI(), MIB);
-  MIB.addUse(Addr);
-  MIB.addImm(CPA->getKey()->getZExtValue());
-  MIB.addUse(AddrDisc);
-  MIB.addImm(CPA->getDiscriminator()->getZExtValue());
-  return MIB;
-}
-
 MachineInstrBuilder MachineIRBuilder::buildBrCond(const SrcOp &Tst,
                                                   MachineBasicBlock &Dest) {
   assert(Tst.getLLTTy(*getMRI()).isScalar() && "invalid operand type");
diff --git a/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp b/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
index f114f1ecc0bae..9c3b31935f6d6 100644
--- a/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
@@ -13,7 +13,6 @@
 
 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/MC/MCSymbol.h"
 
 using namespace llvm;
@@ -42,25 +41,3 @@ MachineModuleInfoImpl::SymbolListTy MachineModuleInfoImpl::getSortedStubs(
   Map.clear();
   return List;
 }
-
-template <typename MachineModuleInfoTarget>
-static typename MachineModuleInfoTarget::AuthStubListTy getAuthGVStubListHelper(
-    DenseMap<MCSymbol *, typename MachineModuleInfoTarget::AuthStubInfo>
-        &AuthPtrStubs) {
-  typename MachineModuleInfoTarget::AuthStubListTy List(AuthPtrStubs.begin(),
-                                                        AuthPtrStubs.end());
-
-  if (!List.empty())
-    llvm::sort(List.begin(), List.end(),
-               [](const typename MachineModuleInfoTarget::AuthStubPairTy &LHS,
-                  const typename MachineModuleInfoTarget::AuthStubPairTy &RHS) {
-                 return LHS.first->getName() < RHS.first->getName();
-               });
-
-  AuthPtrStubs.clear();
-  return List;
-}
-
-MachineModuleInfoELF::AuthStubListTy MachineModuleInfoELF::getAuthGVStubList() {
-  return getAuthGVStubListHelper<MachineModuleInfoELF>(AuthPtrStubs);
-}
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index 0c8a0f2b24a1e..9ea238c61ed91 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2066,12 +2066,6 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
       report("Dst operand 0 must be a pointer", MI);
     break;
   }
-  case TargetOpcode::G_PTRAUTH_GLOBAL_VALUE: {
-    const MachineOperand &AddrOp = MI->getOperand(1);
-    if (!AddrOp.isReg() || !MRI->getType(AddrOp.getReg()).isPointer())
-      report("addr operand must be a pointer", &AddrOp, 1);
-    break;
-  }
   default:
     break;
   }
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index b2f9a9e1d58ef..296b06187ec0f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1802,13 +1802,6 @@ SDValue SelectionDAGBuilder::getValueImpl(const Value *V) {
     if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
       return DAG.getGlobalAddress(GV, getCurSDLoc(), VT);
 
-    if (const ConstantPtrAuth *CPA = dyn_cast<ConstantPtrAuth>(C)) {
-      return DAG.getNode(ISD::PtrAuthGlobalAddress, getCurSDLoc(), VT,
-                         getValue(CPA->getPointer()), getValue(CPA->getKey()),
-                         getValue(CPA->getAddrDiscriminator()),
-                         getValue(CPA->getDiscriminator()));
-    }
-
     if (isa<ConstantPointerNull>(C)) {
       unsigned AS = V->getType()->getPointerAddressSpace();
       return DAG.getConstant(0, getCurSDLoc(),
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index c1d2c095b103c..a7555d6d31f26 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -75,7 +75,6 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
     }
     return "<<Unknown Node #" + utostr(getOpcode()) + ">>";
 
-    // clang-format off
 #ifndef NDEBUG
   case ISD::DELETED_NODE:               return "<<Deleted Node!>>";
 #endif
@@ -127,7 +126,6 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   case ISD::ConstantFP:                 return "ConstantFP";
   case ISD::GlobalAddress:              return "GlobalAddress";
   case ISD::GlobalTLSAddress:           return "GlobalTLSAddress";
-  case ISD::PtrAuthGlobalAddress:       return "PtrAuthGlobalAddress";
   case ISD::FrameIndex:                 return "FrameIndex";
   case ISD::JumpTable:                  return "JumpTable";
   case ISD::JUMP_TABLE_DEBUG_INFO:
@@ -170,6 +168,8 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
       return "OpaqueTargetConstant";
     return "TargetConstant";
 
+    // clang-format off
+
   case ISD::TargetConstantFP:           return "TargetConstantFP";
   case ISD::TargetGlobalAddress:        return "TargetGlobalAddress";
   case ISD::TargetGlobalTLSAddress:     return "TargetGlobalTLSAddress";
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 611c3b579ff15..da11539eab348 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -133,13 +133,6 @@ class AArch64AsmPrinter : public AsmPrinter {
   unsigned emitPtrauthDiscriminator(uint16_t Disc, unsigned AddrDisc,
                                     unsigned &InstsEmitted);
 
-  // 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);
-
   /// tblgen'erated driver function for lowering simple MI->MC
   /// pseudo instructions.
   bool emitPseudoExpansionLowering(MCStreamer &OutStreamer,
@@ -847,15 +840,6 @@ void AArch64AsmPrinter::emitHwasanMemaccessSymbols(Module &M) {
   }
 }
 
-template <typename MachineModuleInfoTarget>
-static void emitAuthenticatedPointer(
-    MCStreamer &OutStreamer, MCSymbol *StubLabel,
-    const typename MachineModuleInfoTarget::AuthStubInfo &StubInfo) {
-  // sym$auth_ptr$key$disc:
-  OutStreamer.emitLabel(StubLabel);
-  OutStreamer.emitValue(StubInfo.AuthPtrRef, /*size=*/8);
-}
-
 void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
   emitHwasanMemaccessSymbols(M);
 
@@ -869,25 +853,6 @@ void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
     OutStreamer->emitAssemblerFlag(MCAF_SubsectionsViaSymbols);
   }
 
-  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<MachineModuleInfoELF>(*OutStreamer, Stub.first,
-                                                       Stub.second);
-
-      OutStreamer->addBlankLine();
-    }
-  }
-
   // Emit stack and fault map information.
   FM.serializeToFaultMapSection();
 
@@ -1658,214 +1623,6 @@ AArch64AsmPrinter::lowerConstantPtrAuth(const ConstantPtrAuth &CPA) {
                                    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.
-  assert(TM.getTargetTriple().isOSBinFormatELF() &&
-         "LOADauthptrstatic is implemented only for ELF");
-  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());
-  MCSymbol *AuthPtrStubSym =
-      TLOF.getAuthPtrSlotSymbol(TM, &MF->getMMI(), 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) {
-  unsigned InstsEmitted = 0;
-  auto EmitAndIncrement = [this, &InstsEmitted](const MCInst &Inst) {
-    EmitToStreamer(*OutStreamer, Inst);
-    ++InstsEmitted;
-  };
-
-  const bool IsGOTLoad = MI.getOpcode() == AArch64::LOADgotPAC;
-  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();
-  assert(isUInt<16>(Disc) &&
-         "constant discriminator is out of range [0, 0xffff]");
-
-  const int64_t Offset = GAOp.getOffset();
-  GAOp.setOffset(0);
-
-  // Emit:
-  // target materialization:
-  // - via GOT:
-  //     adrp x16, :got:target
-  //     ldr x16, [x16, :got_lo12:target]
-  //     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);
-
-  EmitAndIncrement(
-      MCInstBuilder(AArch64::ADRP).addReg(AArch64::X16).addOperand(GAMCHi));
-
-  if (IsGOTLoad) {
-    EmitAndIncrement(MCInstBuilder(AArch64::LDRXui)
-                         .addReg(AArch64::X16)
-                         .addReg(AArch64::X16)
-                         .addOperand(GAMCLo));
-  } else {
-    EmitAndIncrement(MCInstBuilder(AArch64::ADDXri)
-                         .addReg(AArch64::X16)
-                         .addReg(AArch64::X16)
-                         .addOperand(GAMCLo)
-                         .addImm(0));
-  }
-
-  if (Offset != 0) {
-    const uint64_t AbsOffset = (Offset > 0 ? Offset : -((uint64_t)Offset));
-    const bool IsNeg = Offset < 0;
-    if (isUInt<24>(AbsOffset)) {
-      for (int BitPos = 0; BitPos != 24 && (AbsOffset >> BitPos);
-           BitPos += 12) {
-        EmitAndIncrement(
-            MCInstBuilder(IsNeg ? AArch64::SUBXri : AArch64::ADDXri)
-                .addReg(AArch64::X16)
-                .addReg(AArch64::X16)
-                .addImm((AbsOffset >> BitPos) & 0xfff)
-                .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, BitPos)));
-      }
-    } else {
-      constexpr uint64_t Mask16 = 0xffff;
-      const uint64_t UOffset = Offset;
-      EmitAndIncrement(MCInstBuilder(IsNeg ? AArch64::MOVNXi : AArch64::MOVZXi)
-                           .addReg(AArch64::X17)
-                           .addImm((IsNeg ? ~UOffset : UOffset) & Mask16)
-                           .addImm(/*shift=*/0));
-      auto NeedMovk = [Mask16, IsNeg, UOffset](int BitPos) -> bool {
-        assert(BitPos == 16 || BitPos == 32 || BitPos == 48);
-        uint64_t Shifted = UOffset >> BitPos;
-        if (!IsNeg)
-          return Shifted != 0;
-        for (int I = 0; I != 64 - BitPos; I += 16)
-          if (((Shifted >> I) & Mask16) != Mask16)
-            return true;
-        return false;
-      };
-      for (int BitPos =...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/96865


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