Let empty entry BufferType sentinel be static instead of global

Avoids issue where a global BufferType with a transitive Alloc instance
binds to a null reference allocator since the global allocator instance
has not yet been initialized as part of global constructor invocation.

Manually hoist empty sentinel ref outside of loops since it might not
be obvious to the compiler that the same object is reused over and over.

4 files changed, 6 insertions, 4 deletions

diff --git a/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.cpp b/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.cpp
index 54f95e1c543..3f2a1bb1969 100644
--- a/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.cpp
+++ b/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.cpp
@@ -21,9 +21,10 @@ void
 DirectTensorStore::TensorBufferType::cleanHold(void* buffer, size_t offset, ElemCount num_elems, CleanContext clean_ctx)
 {
     TensorSP* elem = static_cast<TensorSP*>(buffer) + offset;
+    const auto& empty = empty_entry();
     for (size_t i = 0; i < num_elems; ++i) {
         clean_ctx.extraBytesCleaned((*elem)->get_memory_usage().allocatedBytes());
-        *elem = _emptyEntry;
+        *elem = empty;
         ++elem;
     }
 }
diff --git a/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.h b/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.h
index 776920ab930..1f112f1ea28 100644
--- a/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.h
+++ b/searchlib/src/vespa/searchlib/tensor/direct_tensor_store.h
@@ -24,7 +24,7 @@ private:
     class TensorBufferType : public vespalib::datastore::BufferType<TensorSP> {
     private:
         using ParentType = BufferType<TensorSP>;
-        using ParentType::_emptyEntry;
+        using ParentType::empty_entry;
         using CleanContext = typename ParentType::CleanContext;
     public:
         TensorBufferType();
diff --git a/searchlib/src/vespa/searchlib/tensor/streamed_value_store.cpp b/searchlib/src/vespa/searchlib/tensor/streamed_value_store.cpp
index 2e6d771a870..a668387e5bd 100644
--- a/searchlib/src/vespa/searchlib/tensor/streamed_value_store.cpp
+++ b/searchlib/src/vespa/searchlib/tensor/streamed_value_store.cpp
@@ -166,9 +166,10 @@ void
 StreamedValueStore::TensorBufferType::cleanHold(void* buffer, size_t offset, ElemCount num_elems, CleanContext clean_ctx)
 {
     TensorEntry::SP* elem = static_cast<TensorEntry::SP*>(buffer) + offset;
+    const auto& empty = empty_entry();
     for (size_t i = 0; i < num_elems; ++i) {
         clean_ctx.extraBytesCleaned((*elem)->get_memory_usage().allocatedBytes());
-        *elem = _emptyEntry;
+        *elem = empty;
         ++elem;
     }
 }
diff --git a/searchlib/src/vespa/searchlib/tensor/streamed_value_store.h b/searchlib/src/vespa/searchlib/tensor/streamed_value_store.h
index 7d83e9f3335..29201dc0e61 100644
--- a/searchlib/src/vespa/searchlib/tensor/streamed_value_store.h
+++ b/searchlib/src/vespa/searchlib/tensor/streamed_value_store.h
@@ -51,7 +51,7 @@ private:
     class TensorBufferType : public vespalib::datastore::BufferType<TensorEntry::SP> {
     private:
         using ParentType = BufferType<TensorEntry::SP>;
-        using ParentType::_emptyEntry;
+        using ParentType::empty_entry;
         using CleanContext = typename ParentType::CleanContext;
     public:
         TensorBufferType() noexcept;