Update the Windows ARM64 unwinder (#92604)

* Update the Windows ARM64 unwinder

This change updates the Windows ARM64 unwinder to match the current
state in Windows. It contains a fix for a bug that is needed as a basis
for a .NET issue fix.

* Reflect PR feedback

Author: janvorli

src/coreclr/inc/crosscomp.h

@@ -282,7 +282,8 @@ typedef struct DECLSPEC_ALIGN(16) _T_CONTEXT {
 } T_CONTEXT, *PT_CONTEXT;
 
 // _IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY (see ExternalAPIs\Win9CoreSystem\inc\winnt.h)
-typedef struct _T_RUNTIME_FUNCTION {
+#ifdef HOST_UNIX
+typedef struct _IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY {
     DWORD BeginAddress;
     union {
         DWORD UnwindData;
@@ -294,12 +295,11 @@ typedef struct _T_RUNTIME_FUNCTION {
             DWORD H : 1;
             DWORD CR : 2;
             DWORD FrameSize : 9;
-        } PackedUnwindData;
+        };
     };
-} T_RUNTIME_FUNCTION, *PT_RUNTIME_FUNCTION;
+} IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY, * PIMAGE_ARM64_RUNTIME_FUNCTION_ENTRY;
 
 
-#ifdef HOST_UNIX
 
 typedef
 EXCEPTION_DISPOSITION
@@ -310,6 +310,8 @@ EXCEPTION_DISPOSITION
     PVOID DispatcherContext
     );
 #endif
+
+typedef IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY T_RUNTIME_FUNCTION, * PT_RUNTIME_FUNCTION;
 //
 // Define exception dispatch context structure.
 //

src/coreclr/pal/inc/pal.h

@@ -2085,6 +2085,34 @@ typedef struct _KNONVOLATILE_CONTEXT_POINTERS {
 
 } KNONVOLATILE_CONTEXT_POINTERS, *PKNONVOLATILE_CONTEXT_POINTERS;
 
+typedef struct _IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY {
+    DWORD BeginAddress;
+    union {
+        DWORD UnwindData;
+        struct {
+            DWORD Flag : 2;
+            DWORD FunctionLength : 11;
+            DWORD RegF : 3;
+            DWORD RegI : 4;
+            DWORD H : 1;
+            DWORD CR : 2;
+            DWORD FrameSize : 9;
+        };
+    };
+} IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY, * PIMAGE_ARM64_RUNTIME_FUNCTION_ENTRY;
+
+typedef union IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY_XDATA {
+    ULONG HeaderData;
+    struct {
+        ULONG FunctionLength : 18;      // in words (2 bytes)
+        ULONG Version : 2;
+        ULONG ExceptionDataPresent : 1;
+        ULONG EpilogInHeader : 1;
+        ULONG EpilogCount : 5;          // number of epilogs or byte index of the first unwind code for the one only epilog
+        ULONG CodeWords : 5;            // number of dwords with unwind codes
+    };
+} IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY_XDATA;
+
 #elif defined(HOST_LOONGARCH64)
 
 // Please refer to src/coreclr/pal/src/arch/loongarch64/asmconstants.h
@@ -3139,13 +3167,17 @@ enum {
 //
 // A function table entry is generated for each frame function.
 //
+#if defined(HOST_ARM64)
+typedef IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY RUNTIME_FUNCTION, *PRUNTIME_FUNCTION;
+#else // HOST_ARM64
 typedef struct _RUNTIME_FUNCTION {
     DWORD BeginAddress;
-#ifdef TARGET_AMD64
+#ifdef HOST_AMD64
     DWORD EndAddress;
 #endif
     DWORD UnwindData;
 } RUNTIME_FUNCTION, *PRUNTIME_FUNCTION;
+#endif // HOST_ARM64
 
 #define STANDARD_RIGHTS_REQUIRED  (0x000F0000L)
 #define SYNCHRONIZE               (0x00100000L)