[runtime] zero-initialize descriptor array padding

joyeecheung · V8 LUCI CQ · commit 6eff00a342cb · 2025-12-19T06:20:05.000-08:00
So that snapshot and code cache stay reproducible. See nodejs/node-v8#304 Change-Id: Ic30970097ab46a26fa5bcf0f73e0fe62089890cc Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7271645 Reviewed-by: Patrick Thier <pthier@chromium.org> Commit-Queue: Joyee Cheung <joyee@igalia.com> Cr-Commit-Position: refs/heads/main@{#104436}
diff --git a/src/objects/objects.cc b/src/objects/objects.cc
@@ -3996,6 +3996,9 @@ void DescriptorArray::Initialize(Tagged<EnumCache> empty_enum_cache,
   set_enum_cache(empty_enum_cache, SKIP_WRITE_BARRIER);
   set_flags(FastIterableBits::encode(FastIterableState::kUnknown),
             kRelaxedStore);
+#if TAGGED_SIZE_8_BYTES
+  set_optional_padding(0);
+#endif
   MemsetTagged(GetDescriptorSlot(0), undefined_value,
                number_of_all_descriptors() * kEntrySize);
 }
