Fix blobstorage crypto module build for aarch64 (#11840)

Author: SammyVimes

ydb/core/blobstorage/crypto/crypto.cpp

@@ -173,14 +173,14 @@ const bool TStreamCypher::HasAVX512 = NX86::HaveAVX512F();
 Y_FORCE_INLINE void TStreamCypher::Encipher(const ui8* plaintext, ui8* ciphertext, size_t len) { 
     std::visit([&](auto&& chacha) {
         chacha.Encipher(plaintext, ciphertext, len);
-    }, *Cypher);
+    }, Cypher);
 }
 
 Y_FORCE_INLINE void TStreamCypher::SetKeyAndIV(const ui64 blockIdx) {
     std::visit([&](auto&& chacha) {
         chacha.SetKey((ui8*)&Key[0], sizeof(Key));
         chacha.SetIV((ui8*)&Nonce, (ui8*)&blockIdx);
-    }, *Cypher);
+    }, Cypher);
 }
 
 TStreamCypher::TStreamCypher()
@@ -189,15 +189,12 @@ TStreamCypher::TStreamCypher()
 {
 #if ENABLE_ENCRYPTION
     memset(Key, 0, sizeof(Key));
-
-    auto* chacha = new std::variant<ChaChaVec, ChaCha512>;
 
     if (HasAVX512) {
-        chacha->emplace<ChaCha512>(CYPHER_ROUNDS);
+        Cypher.emplace<ChaCha512>(CYPHER_ROUNDS);
     } else {
-        chacha->emplace<ChaChaVec>(CYPHER_ROUNDS);
+        Cypher.emplace<ChaChaVec>(CYPHER_ROUNDS);
     }
-    Cypher.reset(chacha);
 #else
     Y_UNUSED(Leftover);
     Y_UNUSED(Key);

ydb/core/blobstorage/crypto/crypto.h

@@ -7,10 +7,10 @@
 #if (defined(_win_) || defined(_arm64_))
 #include <ydb/core/blobstorage/crypto/chacha.h>
 #include <ydb/core/blobstorage/crypto/poly1305.h>
-#define ChaChaVec ChaCha
-#define ChaCha512 ChaCha
-#define Poly1305Vec Poly1305
 #define CHACHA_BPI 1
+using ChaChaVec = ChaCha;
+using Poly1305Vec = Poly1305;
+class ChaCha512 : public ChaCha {};
 #else
 #include <ydb/core/blobstorage/crypto/chacha_vec.h>
 #include <ydb/core/blobstorage/crypto/chacha_512/chacha_512.h>
@@ -104,7 +104,7 @@ class TStreamCypher {
     alignas(16) ui8 Leftover[BLOCK_BYTES];
     alignas(16) ui64 Key[4];
     alignas(16) i64 Nonce;
-    std::unique_ptr<std::variant<ChaChaVec, ChaCha512>> Cypher;
+    std::variant<ChaChaVec, ChaCha512> Cypher;
     ui32 UnusedBytes;
 public:
     TStreamCypher();