Don't use relaxed memory order when accessing class enum values

Reviewed By: jtwarren, jano Differential Revision: D57516812 fbshipit-source-id: 04cbb496fea1c314e4fd1b187db102348f96261e
facebook · May 18, 2024 · 0bd9816 · 0bd9816
1 parent 987d4b9
commit 0bd9816
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/hphp/runtime/vm/class-inl.h b/hphp/runtime/vm/class-inl.h
@@ -696,7 +696,7 @@ inline MaybeDataType Class::enumBaseTy() const {
 }
 
 inline EnumValues* Class::getEnumValues() const {
-  return m_extra->m_enumValues.load(std::memory_order_relaxed);
+  return m_extra->m_enumValues.load(std::memory_order_acquire);
 }
 
 ///////////////////////////////////////////////////////////////////////////////

diff --git a/hphp/runtime/vm/class.cpp b/hphp/runtime/vm/class.cpp
@@ -430,7 +430,7 @@ EnumValues* Class::setEnumValues(EnumValues* values) {
   auto extra = m_extra.ensureAllocated();
   EnumValues* expected = nullptr;
   if (!extra->m_enumValues.compare_exchange_strong(
-        expected, values, std::memory_order_relaxed)) {
+        expected, values, std::memory_order_acq_rel)) {
     // Already set by someone else, use theirs.
     delete values;
     return expected;
@@ -440,7 +440,7 @@ EnumValues* Class::setEnumValues(EnumValues* values) {
 }
 
 Class::ExtraData::~ExtraData() {
-  delete m_enumValues.load(std::memory_order_relaxed);
+  delete m_enumValues.load(std::memory_order_acquire);
   if (m_lsbMemoExtra.m_handles) {
     for (auto const& kv : m_lsbMemoExtra.m_symbols) {
       rds::unbind(kv.first, kv.second);