[libunwind] 710590e - [libunwind] Undefined behaviour pointer arithmetic with null pointer (#98648)

[via cfe-commits]

Author: Daniel Kiss
Date: 2024-08-05T11:16:51+02:00
New Revision: 710590e33d19649f08c716d827eb465e3a132d23

URL: https://github.com/llvm/llvm-project/commit/710590e33d19649f08c716d827eb465e3a132d23
DIFF: https://github.com/llvm/llvm-project/commit/710590e33d19649f08c716d827eb465e3a132d23.diff

LOG: [libunwind] Undefined behaviour pointer arithmetic with null pointer (#98648)

Fixes #91144

Added: 
    

Modified: 
    libunwind/src/UnwindCursor.hpp

Removed: 
    


################################################################################
diff  --git a/libunwind/src/UnwindCursor.hpp b/libunwind/src/UnwindCursor.hpp
index 06e654197351d..ce6dced535e78 100644
--- a/libunwind/src/UnwindCursor.hpp
+++ b/libunwind/src/UnwindCursor.hpp
@@ -230,8 +230,8 @@ void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
 }
 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
 
-
-#define arrayoffsetof(type, index, field) ((size_t)(&((type *)0)[index].field))
+#define arrayoffsetof(type, index, field)                                      \
+  (sizeof(type) * (index) + offsetof(type, field))
 
 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
 template <typename A> class UnwindSectionHeader {