Update ImportThunk to use ADRP/LDR pairs for ARM64 ModuleImport references

Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Author: Copilot

src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/ImportThunk.cs

@@ -64,14 +64,14 @@ public ImportThunk(NodeFactory factory, ReadyToRunHelper helperId, ImportSection
             }
 
             if (_thunkKind != Kind.Eager
-                && factory.Target.Architecture is Internal.TypeSystem.TargetArchitecture.ARM64
-                    or Internal.TypeSystem.TargetArchitecture.LoongArch64
+                && factory.Target.Architecture is Internal.TypeSystem.TargetArchitecture.LoongArch64
                     or Internal.TypeSystem.TargetArchitecture.RiscV64)
             {
                 // We stuff the reloc to the module import pointer before the start of the thunk
                 // to ensure alignment.
                 // The thunk itself starts immediately after the reloc.
                 // We don't need this for an Eager thunk.
+                // Note: ARM64 now uses ADRP/LDR pairs and doesn't need this offset
                 _symbolOffset = 8;
             }
         }

src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/Target_ARM64/ImportThunk.cs

@@ -21,13 +21,6 @@ protected override void EmitCode(NodeFactory factory, ref ARM64Emitter instructi
                 return;
             }
 
-            instructionEncoder.Builder.RequireInitialPointerAlignment();
-            Debug.Assert(instructionEncoder.Builder.CountBytes == 0);
-
-            instructionEncoder.Builder.EmitReloc(factory.ModuleImport, RelocType.IMAGE_REL_BASED_DIR64);
-
-            Debug.Assert(instructionEncoder.Builder.CountBytes == ((ISymbolNode)this).Offset);
-
             if (relocsOnly)
             {
                 // When doing relocs only, we don't need to generate the actual instructions
@@ -50,8 +43,11 @@ protected override void EmitCode(NodeFactory factory, ref ARM64Emitter instructi
                     instructionEncoder.EmitMOV(Register.X9, checked((ushort)index));
 
                     // Move Module* -> x10
-                    // ldr x10, [PC-0xc]
-                    instructionEncoder.EmitLDR(Register.X10, -0xc);
+                    // adrp x10, ModuleImport
+                    instructionEncoder.EmitADRP(Register.X10, factory.ModuleImport);
+
+                    // ldr x10, [x10, ModuleImport page offset]
+                    instructionEncoder.EmitLDR(Register.X10, Register.X10, factory.ModuleImport);
 
                     // ldr x10, [x10]
                     instructionEncoder.EmitLDR(Register.X10, Register.X10);
@@ -60,8 +56,11 @@ protected override void EmitCode(NodeFactory factory, ref ARM64Emitter instructi
                 case Kind.Lazy:
 
                     // Move Module* -> x1
-                    // ldr x1, [PC-0x8]
-                    instructionEncoder.EmitLDR(Register.X1, -0x8);
+                    // adrp x1, ModuleImport
+                    instructionEncoder.EmitADRP(Register.X1, factory.ModuleImport);
+
+                    // ldr x1, [x1, ModuleImport page offset]
+                    instructionEncoder.EmitLDR(Register.X1, Register.X1, factory.ModuleImport);
 
                     // ldr x1, [x1]
                     instructionEncoder.EmitLDR(Register.X1, Register.X1);