Refactor CompressedWeights.

PiperOrigin-RevId: 643934198

backprop/backward-inl.h

@@ -357,7 +357,7 @@ static HWY_NOINLINE void CrossEntropyLossGrad(
   }
 }
 
-template <typename TConfig, template<typename> typename WeightsT,
+template <typename TConfig, template<typename...> typename WeightsT,
           template<typename> typename LayerT>
 void CrossEntropyLossBackwardPass(const Prompt& prompt,
                                   const WeightsT<TConfig>& weights,

backprop/forward-inl.h

@@ -222,7 +222,7 @@ void ApplyForwardLayer(const LayerT<TConfig>& weights,
   }
 }
 
-template <typename TConfig, template<typename> typename WeightsT,
+template <typename TConfig, template<typename...> typename WeightsT,
           template<typename> typename LayerT>
 float CrossEntropyLossForwardPass(const std::vector<int>& prompt,
                                   size_t context_size,

gemma/common.cc

@@ -30,15 +30,18 @@ namespace gcpp {
 
 const char* ParseModelTypeAndTraining(const std::string& model_flag,
                                       Model& model, ModelTraining& training) {
-  constexpr const char* kModelFlags[] = {"2b-pt", "7b-pt",   "gr2b-pt", "2b-it",
-                                         "7b-it", "gr2b-it", "tiny"};
+  constexpr const char* kModelFlags[] = {
+      "2b-pt", "7b-pt", "gr2b-pt", "2b-it", "7b-it", "gr2b-it", "tiny",
+  };
   constexpr Model kModelTypes[] = {
-      Model::GEMMA_2B, Model::GEMMA_7B,   Model::GRIFFIN_2B, Model::GEMMA_2B,
-      Model::GEMMA_7B, Model::GRIFFIN_2B, Model::GEMMA_TINY};
+      Model::GEMMA_2B, Model::GEMMA_7B, Model::GRIFFIN_2B, Model::GEMMA_2B,
+      Model::GEMMA_7B, Model::GRIFFIN_2B, Model::GEMMA_TINY,
+  };
   constexpr ModelTraining kModelTraining[] = {
       ModelTraining::GEMMA_PT, ModelTraining::GEMMA_PT, ModelTraining::GEMMA_PT,
       ModelTraining::GEMMA_IT, ModelTraining::GEMMA_IT, ModelTraining::GEMMA_IT,
-      ModelTraining::GEMMA_IT};
+      ModelTraining::GEMMA_IT,
+  };
 
   constexpr size_t kNum = std::end(kModelFlags) - std::begin(kModelFlags);
   static char kErrorMessageBuffer[kNum * 8 + 1024] =

gemma/weights.cc

@@ -43,7 +43,7 @@ struct LoadCompressedWeightsT {
     using CWeights = CompressedWeights<TConfig>;
     ByteStorageT c_weights_u8 = AllocateSizeof<CWeights>();
     CWeights* c_weights = reinterpret_cast<CWeights*>(c_weights_u8.get());
-    new (&c_weights->c_layer_ptrs) CompressedLayerPointers<TConfig>(pool);
+    new (c_weights) CWeights(pool);
 
     std::array<float, TConfig::kNumTensorScales> scales;
     CacheLoader loader(weights);

gemma/weights.h

@@ -207,9 +207,15 @@ struct CompressedLayerPointers {
   std::array<hwy::AlignedFreeUniquePtr<CLayer[]>, TConfig::kLayers> c_layers;
 };
 
-template <class TConfig>
+template <class TConfig, typename = void>
 struct CompressedWeights {
-  // No ctor/dtor, allocated via AllocateAligned.
+  // Must be allocated via AllocateAligned and initialized with placement new.
+  void* operator new(size_t, void* addr) { return addr; }
+  void* operator new(size_t) = delete;
+  void* operator new[](size_t) = delete;
+  void operator delete(void*) = delete;
+  void operator delete[](void*) = delete;
+
   using Weight = typename TConfig::Weight;
 
   using WeightF32OrInputT =
@@ -224,6 +230,16 @@ struct CompressedWeights {
   // Must be last so that the other arrays remain aligned.
   CompressedLayerPointers<TConfig> c_layer_ptrs;
 
+  explicit CompressedWeights(hwy::ThreadPool& pool) : c_layer_ptrs(pool) {}
+
+  void ZeroInit() {
+    hwy::ZeroBytes(&embedder_input_embedding, sizeof(embedder_input_embedding));
+    hwy::ZeroBytes(&final_norm_scale, sizeof(final_norm_scale));
+    for (int i = 0; i < TConfig::kLayers; ++i) {
+      hwy::ZeroBytes(GetLayer(i), sizeof(*GetLayer(i)));
+    }
+  }
+
   const CompressedLayer<TConfig>* GetLayer(size_t layer) const {
     return c_layer_ptrs.c_layers[layer].get();
   }
@@ -260,7 +276,7 @@ struct AllocateCompressedWeights {
     using TWeights = CompressedWeights<TConfig>;
     ByteStorageT weights_u8 = AllocateSizeof<TWeights>();
     TWeights* weights = reinterpret_cast<TWeights*>(weights_u8.get());
-    new (&weights->c_layer_ptrs) CompressedLayerPointers<TConfig>(pool);
+    new (weights) TWeights(pool);
     return weights_u8;
   }
 };
@@ -291,12 +307,7 @@ struct ZeroInitCompressedWeights {
   void operator()(ByteStorageT& weights, hwy::ThreadPool& pool) const {
     CompressedWeights<TConfig>& w =
         *reinterpret_cast<CompressedWeights<TConfig>*>(weights.get());
-    hwy::ZeroBytes(&w.embedder_input_embedding,
-                   sizeof(w.embedder_input_embedding));
-    hwy::ZeroBytes(&w.final_norm_scale, sizeof(w.final_norm_scale));
-    for (int i = 0; i < TConfig::kLayers; ++i) {
-      hwy::ZeroBytes(w.GetLayer(i), sizeof(*w.GetLayer(i)));
-    }
+    w.ZeroInit();
   }
 };
 
@@ -320,7 +331,7 @@ struct DeleteLayersPtrs {
   void operator()(ByteStorageT& weights_u8) const {
     auto* weights =
         reinterpret_cast<CompressedWeights<TConfig>*>(weights_u8.get());
-    weights->c_layer_ptrs.~CompressedLayerPointers<TConfig>();
+    weights->~CompressedWeights<TConfig>();
   }
 };
 
@@ -358,10 +369,6 @@ void LogWeightStats(Model model, Type weight_type, const ByteStorageT& weights);
 // ----------------------------------------------------------------------------
 // Iterators
 
-#define GEMMA_CALL_FUNC(name, member)                          \
-  snprintf(name_buf, sizeof(name_buf), name "_%d", layer_idx); \
-  func(name_buf, layer ? layer->member.data() : nullptr, layer_weights->member)
-
 // Calls func(name, float*, CompressedArray&) for each tensor. float* is null
 // if weights = null, which happens during the first call where we attempt to
 // load from cache.
@@ -376,6 +383,10 @@ void ForEachTensor(const WeightsF<TConfig>* weights,
   func("c_final_norm", weights ? weights->final_norm_scale.data() : nullptr,
        c_weights.final_norm_scale);
 
+#define GEMMA_CALL_FUNC(name, member)                          \
+  snprintf(name_buf, sizeof(name_buf), name "_%d", layer_idx); \
+  func(name_buf, layer ? layer->member.data() : nullptr, layer_weights->member)
+
   char name_buf[16];
   for (int layer_idx = 0; layer_idx < TConfig::kLayers; ++layer_idx) {
     auto type = TConfig::kLayerConfig[layer_idx];
@@ -418,9 +429,8 @@ void ForEachTensor(const WeightsF<TConfig>* weights,
       GEMMA_CALL_FUNC("attn_ob", attention_output_biases);
     }
   }
-}
-
 #undef GEMMA_CALL_FUNC
+}  // ForEachTensor
 
 #define GEMMA_CALL_TOP_FUNC1(name, member) func(name, weights1.member)
 #define GEMMA_CALL_TOP_FUNC2(name, member)      \