arm64e/ptrauth unified patch: libcxx/abi

Author: ahmedbougacha

libcxx/include/typeinfo

@@ -299,7 +299,15 @@ struct __type_info_implementations {
      __impl;
 };
 
-class _LIBCPP_EXPORTED_FROM_ABI type_info
+#if defined(__arm64__) && __has_cpp_attribute(clang::ptrauth_vtable_pointer)
+#define _LIBCPP_TYPE_INFO_VTABLE_POINTER_AUTH \
+   [[clang::ptrauth_vtable_pointer(process_independent, no_address_discrimination, no_extra_discrimination)]]
+#else
+#define _LIBCPP_TYPE_INFO_VTABLE_POINTER_AUTH
+#endif
+
+
+class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_TYPE_INFO_VTABLE_POINTER_AUTH type_info
 {
   type_info& operator=(const type_info&);
   type_info(const type_info&);

libcxxabi/src/private_typeinfo.cpp

@@ -50,6 +50,21 @@
 #include <atomic>
 #endif
 
+#if __has_feature(ptrauth_calls)
+#include <ptrauth.h>
+#endif
+
+
+template<typename T>
+static inline
+T *
+get_vtable(T *vtable) {
+#if __has_feature(ptrauth_calls)
+    vtable = ptrauth_strip(vtable, ptrauth_key_cxx_vtable_pointer);
+#endif
+    return vtable;
+}
+
 static inline
 bool
 is_equal(const std::type_info* x, const std::type_info* y, bool use_strcmp)
@@ -102,6 +117,7 @@ void dyn_cast_get_derived_info(derived_object_info* info, const void* static_ptr
     info->dynamic_type = *(reinterpret_cast<const __class_type_info* const*>(ptr_to_ti_proxy));
 #else
     void **vtable = *static_cast<void ** const *>(static_ptr);
+    vtable = get_vtable(vtable);
     info->offset_to_derived = reinterpret_cast<ptrdiff_t>(vtable[-2]);
     info->dynamic_ptr = static_cast<const char*>(static_ptr) + info->offset_to_derived;
     info->dynamic_type = static_cast<const __class_type_info*>(vtable[-1]);
@@ -556,6 +572,7 @@ __base_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
         if (__offset_flags & __virtual_mask)
         {
             const char* vtable = *static_cast<const char*const*>(adjustedPtr);
+            vtable = get_vtable(vtable);
             offset_to_base = update_offset_to_base(vtable, offset_to_base);
         }
     }
@@ -1475,6 +1492,7 @@ __base_class_type_info::search_above_dst(__dynamic_cast_info* info,
     if (__offset_flags & __virtual_mask)
     {
         const char* vtable = *static_cast<const char*const*>(current_ptr);
+        vtable = get_vtable(vtable);
         offset_to_base = update_offset_to_base(vtable, offset_to_base);
     }
     __base_type->search_above_dst(info, dst_ptr,
@@ -1495,6 +1513,7 @@ __base_class_type_info::search_below_dst(__dynamic_cast_info* info,
     if (__offset_flags & __virtual_mask)
     {
         const char* vtable = *static_cast<const char*const*>(current_ptr);
+        vtable = get_vtable(vtable);
         offset_to_base = update_offset_to_base(vtable, offset_to_base);
     }
     __base_type->search_below_dst(info,