Windows build fixes: struct vs class, unused arg/var, avoid VLA

PiperOrigin-RevId: 724216434

compression/fields.h

@@ -50,7 +50,7 @@ namespace gcpp {
 //   fields: not required for the intended use case of `ModelConfig`.
 // - support any other languages than C++ and Python (for the exporter).
 
-class IFields;  // breaks circular dependency
+struct IFields;  // breaks circular dependency
 
 // Visitors are internal-only, but their base class is visible to user code
 // because their `IFields::VisitFields` calls `visitor.operator()`.

compression/nuq-inl.h

@@ -252,7 +252,6 @@ class NuqClustering {
     using VF = hn::Vec<decltype(df)>;
     using MF = hn::Mask<decltype(df)>;
     using VI = hn::Vec<decltype(di)>;
-    const VI k1 = hn::Set(di, 1);
     const size_t N = hn::Lanes(df);
     HWY_DASSERT(kGroupSize % N == 0);
 

gemma/configs.cc

@@ -207,6 +207,7 @@ static LayerConfig LayerConfigGriffin2B(size_t model_dim) {
   config.kv_heads = 1;
   config.qkv_dim = 256;
   config.conv1d_width = 4;
+  HWY_DASSERT(config.conv1d_width <= kMaxConv1DWidth);
   config.ff_biases = true;
   config.softmax_attn_output_biases = true;
   config.optimized_gating = false;

gemma/configs.h

@@ -44,6 +44,7 @@ namespace gcpp {
 static constexpr size_t kSeqLen = GEMMA_MAX_SEQLEN;
 static constexpr size_t kTopK = GEMMA_TOPK;
 static constexpr size_t kVocabSize = 256000;
+static constexpr size_t kMaxConv1DWidth = 4;
 
 using EmbedderInputT = BF16;
 

gemma/gemma-inl.h

@@ -109,7 +109,7 @@ HWY_NOINLINE void GriffinRecurrent(size_t batch_start, size_t num_tokens,
     const size_t layer_offset = layer * model_dim * (conv_1d_width - 1);
 
     // cache[i] = input at time t-i.
-    float* HWY_RESTRICT cache[HWY_MAX(conv_1d_width, 1)];
+    float* HWY_RESTRICT cache[kMaxConv1DWidth];
     cache[0] = x;
     for (size_t i = 1; i < conv_1d_width; i++) {
       cache[i] =
@@ -887,6 +887,7 @@ HWY_NOINLINE void VitTransformerLayer(size_t num_tokens, size_t layer,
   const size_t model_dim = activations.weights_config.model_dim;
   auto type = layer_weights->layer_config.type;
   HWY_DASSERT(type == LayerAttentionType::kVit);
+  (void)type;
 
   auto& x = activations.x;
   HWY_DASSERT(x.BatchSize() == num_tokens);

gemma/weights.h

@@ -189,7 +189,7 @@ struct LayerWeightsPtrs {
     }                                                                       \
     if (tensors[0]->Ptr() != nullptr || fet != ForEachType::kIgnoreNulls) { \
       func(ptrs[0]->member.CacheName(layer_idx, sep, sep_index).c_str(),    \
-           hwy::Span<MatPtr*>(tensors, ptrs.size()));                       \
+           hwy::Span<MatPtr*>(tensors.data(), ptrs.size()));                \
     }                                                                       \
   }
 
@@ -197,7 +197,7 @@ struct LayerWeightsPtrs {
   static void ForEachTensor(const std::vector<LayerWeightsPtrs<Weight>*>& ptrs,
                             int layer_idx, ForEachType fet, Func func,
                             char sep = ' ', int sep_index = -1) {
-    MatPtr* tensors[ptrs.size()];
+    std::vector<MatPtr*> tensors(ptrs.size(), nullptr);
     auto type = ptrs[0]->layer_config.type;
     if (type == LayerAttentionType::kVit) {
       // MHA.
@@ -449,7 +449,7 @@ struct ModelWeightsPtrs {
                             ForEachType fet, Func func) {
     std::vector<LayerWeightsPtrs<Weight>*> layers(ptrs.size());
     std::vector<LayerWeightsPtrs<Weight>*> vit_layers(ptrs.size());
-    MatPtr* tensors[ptrs.size()];
+    std::vector<MatPtr*> tensors(ptrs.size(), nullptr);
     // Variables used by GEMMA_CALL_FUNC.
     int layer_idx = -1;
     char sep = ' ';