Fix ARM32 NativeAOT SIGSEGV: restore VRS helpers and __unw_*_reg outside _LIBUNWIND_NATIVEAOT guard

src/native/external/llvm-libunwind-version.txt

@@ -4,3 +4,4 @@ https://github.com/llvm/llvm-project/releases/tag/llvmorg-22.1.1
 Apply https://github.com/dotnet/runtime/commit/35b7d59fa1075ab0fefb921393409806a821d8ed
 Apply https://github.com/dotnet/runtime/commit/be5f98fb6702704afbaf705dce0b54d55479c6f1
 Apply https://github.com/dotnet/runtime/commit/fde4a5bd965b128318e17a3b8ba1dc0fcf8df4a0
+Apply https://github.com/dotnet/runtime/commit/5697904ea1bce4dea47d2d12c89a2c82dd0d18b5

src/native/external/llvm-libunwind/src/Unwind-EHABI.cpp

@@ -443,10 +443,11 @@ _Unwind_VRS_Interpret(_Unwind_Context *context, const uint32_t *data,
   return _URC_CONTINUE_UNWIND;
 }
 
-// The C++ exception dispatch functions below depend on __unw_step and other
-// public API functions from libunwind.cpp which are guarded out when
-// _LIBUNWIND_NATIVEAOT is defined. NativeAOT does not use these - it only
-// uses _Unwind_VRS_Interpret above.
+// The C++ exception dispatch functions in the two #if !defined(_LIBUNWIND_NATIVEAOT)
+// blocks below depend on __unw_step and other public API functions from libunwind.cpp
+// which are guarded out when _LIBUNWIND_NATIVEAOT is defined. NativeAOT does not use
+// these - it only uses _Unwind_VRS_Interpret above, which depends on
+// _Unwind_VRS_Get/Set/Pop defined between the two guard blocks.
 #if !defined(_LIBUNWIND_NATIVEAOT)
 
 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code
@@ -891,6 +892,8 @@ _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) {
   return result;
 }
 
+#endif // !defined(_LIBUNWIND_NATIVEAOT)
+
 // Only used in _LIBUNWIND_TRACE_API, which is a no-op when assertions are
 // disabled.
 [[gnu::unused]] static uint64_t
@@ -1154,6 +1157,8 @@ _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
   _LIBUNWIND_ABORT("unsupported register class");
 }
 
+#if !defined(_LIBUNWIND_NATIVEAOT)
+
 /// Not used by C++.
 /// Unwinds stack, calling "stop" function at each frame.
 /// Could be used to implement longjmp().

src/native/external/llvm-libunwind/src/libunwind.cpp

@@ -26,14 +26,19 @@
 #include <sanitizer/asan_interface.h>
 #endif
 
-#if !defined(_LIBUNWIND_NATIVEAOT)
-
 #if !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 #include "AddressSpace.hpp"
 #include "UnwindCursor.hpp"
 
 using namespace libunwind;
 
+// The singleton, cursor initialization, and most __unw_* functions are
+// excluded from NativeAOT. The register accessors (__unw_get/set_reg,
+// __unw_get/set_fpreg, __unw_save_vfp_as_X) are kept unconditional because
+// they are called by _Unwind_VRS_Get/Set/Pop (Unwind-EHABI.cpp) which in
+// turn are called by _Unwind_VRS_Interpret on ARM32 NativeAOT managed frames.
+#if !defined(_LIBUNWIND_NATIVEAOT)
+
 /// internal object to represent this processes address space
 LocalAddressSpace LocalAddressSpace::sThisAddressSpace;
 
@@ -96,6 +101,8 @@ _LIBUNWIND_HIDDEN int __unw_init_local(unw_cursor_t *cursor,
 }
 _LIBUNWIND_WEAK_ALIAS(__unw_init_local, unw_init_local)
 
+#endif // !defined(_LIBUNWIND_NATIVEAOT)
+
 /// Get value of specified register at cursor position in stack frame.
 _LIBUNWIND_HIDDEN int __unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
                                     unw_word_t *value) {
@@ -223,6 +230,8 @@ _LIBUNWIND_HIDDEN int __unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
 }
 _LIBUNWIND_WEAK_ALIAS(__unw_set_fpreg, unw_set_fpreg)
 
+#if !defined(_LIBUNWIND_NATIVEAOT)
+
 /// Get location of specified register at cursor position in stack frame.
 _LIBUNWIND_HIDDEN int __unw_get_save_loc(unw_cursor_t *cursor, int regNum,
                                        unw_save_loc_t* location)
@@ -353,6 +362,8 @@ _LIBUNWIND_EXPORT uintptr_t __unw_get_data_rel_base(unw_cursor_t *cursor) {
 _LIBUNWIND_WEAK_ALIAS(__unw_get_data_rel_base, unw_get_data_rel_base)
 #endif
 
+#endif // !defined(_LIBUNWIND_NATIVEAOT)
+
 #ifdef __arm__
 // Save VFP registers d0-d15 using FSTMIADX instead of FSTMIADD
 _LIBUNWIND_HIDDEN void __unw_save_vfp_as_X(unw_cursor_t *cursor) {
@@ -364,6 +375,7 @@ _LIBUNWIND_HIDDEN void __unw_save_vfp_as_X(unw_cursor_t *cursor) {
 _LIBUNWIND_WEAK_ALIAS(__unw_save_vfp_as_X, unw_save_vfp_as_X)
 #endif
 
+#if !defined(_LIBUNWIND_NATIVEAOT)
 
 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
 /// SPI: walks cached DWARF entries
@@ -465,8 +477,12 @@ _LIBUNWIND_HIDDEN const char *__unw_strerror(int error_code) {
 }
 _LIBUNWIND_WEAK_ALIAS(__unw_strerror, unw_strerror)
 
+#endif // !defined(_LIBUNWIND_NATIVEAOT)
+
 #endif // !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__wasm__)
 
+#if !defined(_LIBUNWIND_NATIVEAOT)
+
 #ifdef __APPLE__
 
 namespace libunwind {