[wasm] Remove indirection to WasmModule::signature_zone

The zone should just be a member of {WasmModule} instead of a
heap-allocated second object.

R=ahaas@chromium.org

Change-Id: I9cf7d5145ea9131a5ae3382c6f5aa63b816d9aa4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4080032
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84690}

src/wasm/module-decoder-impl.h

@@ -314,8 +314,6 @@ class ModuleDecoderTemplate : public Decoder {
                         ModuleOrigin origin, Tracer& tracer)
       : Decoder(wire_bytes),
         enabled_features_(enabled_features),
-        module_(std::make_shared<WasmModule>(std::make_unique<Zone>(
-            GetWasmEngine()->allocator(), "signatures"))),
         module_start_(wire_bytes.begin()),
         module_end_(wire_bytes.end()),
         tracer_(tracer) {
@@ -583,15 +581,15 @@ class ModuleDecoderTemplate : public Decoder {
     tracer_.Description(TypeKindName(kind));
     switch (kind) {
       case kWasmFunctionTypeCode: {
-        const FunctionSig* sig = consume_sig(module_->signature_zone.get());
+        const FunctionSig* sig = consume_sig(&module_->signature_zone);
         return {sig, kNoSuperType};
       }
       case kWasmStructTypeCode: {
-        const StructType* type = consume_struct(module_->signature_zone.get());
+        const StructType* type = consume_struct(&module_->signature_zone);
         return {type, kNoSuperType};
       }
       case kWasmArrayTypeCode: {
-        const ArrayType* type = consume_array(module_->signature_zone.get());
+        const ArrayType* type = consume_array(&module_->signature_zone);
         return {type, kNoSuperType};
       }
       default:
@@ -645,7 +643,7 @@ class ModuleDecoderTemplate : public Decoder {
         switch (opcode) {
           case kWasmFunctionTypeCode: {
             consume_bytes(1, "function");
-            const FunctionSig* sig = consume_sig(module_->signature_zone.get());
+            const FunctionSig* sig = consume_sig(&module_->signature_zone);
             if (!ok()) break;
             module_->types[i] = {sig, kNoSuperType};
             type_canon->AddRecursiveGroup(module_.get(), 1, i);
@@ -1690,7 +1688,7 @@ class ModuleDecoderTemplate : public Decoder {
 
  private:
   const WasmFeatures enabled_features_;
-  std::shared_ptr<WasmModule> module_;
+  const std::shared_ptr<WasmModule> module_ = std::make_shared<WasmModule>();
   const byte* module_start_ = nullptr;
   const byte* module_end_ = nullptr;
   Tracer& tracer_;

src/wasm/wasm-module.cc

@@ -14,6 +14,7 @@
 #include "src/wasm/jump-table-assembler.h"
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-code-manager.h"
+#include "src/wasm/wasm-engine.h"
 #include "src/wasm/wasm-init-expr.h"
 #include "src/wasm/wasm-js.h"
 #include "src/wasm/wasm-module-builder.h"  // For {ZoneBuffer}.
@@ -213,8 +214,8 @@ std::ostream& operator<<(std::ostream& os, const WasmFunctionName& name) {
   return os;
 }
 
-WasmModule::WasmModule(std::unique_ptr<Zone> signature_zone)
-    : signature_zone(std::move(signature_zone)) {}
+WasmModule::WasmModule()
+    : signature_zone(GetWasmEngine()->allocator(), "signature zone") {}
 
 bool IsWasmCodegenAllowed(Isolate* isolate, Handle<Context> context) {
   // TODO(wasm): Once wasm has its own CSP policy, we should introduce a
@@ -624,9 +625,7 @@ inline size_t VectorSize(const std::vector<T>& vector) {
 
 size_t EstimateStoredSize(const WasmModule* module) {
   return sizeof(WasmModule) + VectorSize(module->globals) +
-         (module->signature_zone ? module->signature_zone->allocation_size()
-                                 : 0) +
-         VectorSize(module->types) +
+         module->signature_zone.allocation_size() + VectorSize(module->types) +
          VectorSize(module->isorecursive_canonical_type_ids) +
          VectorSize(module->functions) + VectorSize(module->data_segments) +
          VectorSize(module->tables) + VectorSize(module->import_table) +

src/wasm/wasm-module.h

@@ -481,7 +481,7 @@ struct WasmTable;
 // Static representation of a module.
 struct V8_EXPORT_PRIVATE WasmModule {
   // ================ Fields ===================================================
-  std::unique_ptr<Zone> signature_zone;
+  Zone signature_zone;
   uint32_t initial_pages = 0;      // initial size of the memory in 64k pages
   uint32_t maximum_pages = 0;      // maximum size of the memory in 64k pages
   bool has_shared_memory = false;  // true if memory is a SharedArrayBuffer
@@ -545,7 +545,7 @@ struct V8_EXPORT_PRIVATE WasmModule {
   mutable std::unique_ptr<std::atomic<uint8_t>[]> validated_functions;
 
   // ================ Constructors =============================================
-  explicit WasmModule(std::unique_ptr<Zone> signature_zone = nullptr);
+  WasmModule();
   WasmModule(const WasmModule&) = delete;
   WasmModule& operator=(const WasmModule&) = delete;
 

test/unittests/wasm/function-body-decoder-unittest.cc

@@ -75,8 +75,7 @@ enum MemoryType { kMemory32, kMemory64 };
 // globals, or memories.
 class TestModuleBuilder {
  public:
-  explicit TestModuleBuilder(ModuleOrigin origin = kWasmOrigin)
-      : allocator(), mod(std::make_unique<Zone>(&allocator, ZONE_NAME)) {
+  explicit TestModuleBuilder(ModuleOrigin origin = kWasmOrigin) {
     mod.origin = origin;
   }
   byte AddGlobal(ValueType type, bool mutability = true) {
@@ -124,7 +123,7 @@ class TestModuleBuilder {
 
   byte AddStruct(std::initializer_list<F> fields,
                  uint32_t supertype = kNoSuperType) {
-    StructType::Builder type_builder(mod.signature_zone.get(),
+    StructType::Builder type_builder(&mod.signature_zone,
                                      static_cast<uint32_t>(fields.size()));
     for (F field : fields) {
       type_builder.AddField(field.first, field.second);
@@ -135,7 +134,7 @@ class TestModuleBuilder {
   }
 
   byte AddArray(ValueType type, bool mutability) {
-    ArrayType* array = mod.signature_zone->New<ArrayType>(type, mutability);
+    ArrayType* array = mod.signature_zone.New<ArrayType>(type, mutability);
     mod.add_array_type(array, kNoSuperType);
     GetTypeCanonicalizer()->AddRecursiveGroup(module(), 1);
     return static_cast<byte>(mod.types.size() - 1);
@@ -191,7 +190,6 @@ class TestModuleBuilder {
     return static_cast<byte>(mod.functions.size() - 1);
   }
 
-  AccountingAllocator allocator;
   WasmModule mod;
 };
 
@@ -5033,7 +5031,6 @@ TEST_F(TypeReaderTest, HeapTypeDecodingTest) {
 
 class LocalDeclDecoderTest : public TestWithZone {
  public:
-  v8::internal::AccountingAllocator allocator;
   WasmFeatures enabled_features_;
 
   size_t ExpectRun(ValueType* local_types, size_t pos, ValueType expected,

test/unittests/wasm/subtyping-unittest.cc

@@ -27,7 +27,7 @@ FieldInit immut(ValueType type) { return FieldInit(type, false); }
 void DefineStruct(WasmModule* module, std::initializer_list<FieldInit> fields,
                   uint32_t supertype = kNoSuperType,
                   bool in_singleton_rec_group = true) {
-  StructType::Builder builder(module->signature_zone.get(),
+  StructType::Builder builder(&module->signature_zone,
                               static_cast<uint32_t>(fields.size()));
   for (FieldInit field : fields) {
     builder.AddField(field.first, field.second);
@@ -41,7 +41,7 @@ void DefineStruct(WasmModule* module, std::initializer_list<FieldInit> fields,
 void DefineArray(WasmModule* module, FieldInit element_type,
                  uint32_t supertype = kNoSuperType,
                  bool in_singleton_rec_group = true) {
-  module->add_array_type(module->signature_zone->New<ArrayType>(
+  module->add_array_type(module->signature_zone.New<ArrayType>(
                              element_type.first, element_type.second),
                          supertype);
   if (in_singleton_rec_group) {
@@ -55,8 +55,7 @@ void DefineSignature(WasmModule* module,
                      uint32_t supertype = kNoSuperType,
                      bool in_singleton_rec_group = true) {
   module->add_signature(
-      FunctionSig::Build(module->signature_zone.get(), returns, params),
-      supertype);
+      FunctionSig::Build(&module->signature_zone, returns, params), supertype);
   if (in_singleton_rec_group) {
     GetTypeCanonicalizer()->AddRecursiveGroup(module, 1);
   }
@@ -66,8 +65,8 @@ TEST_F(WasmSubtypingTest, Subtyping) {
   FLAG_SCOPE(experimental_wasm_gc);
   FLAG_VALUE_SCOPE(wasm_gc_structref_as_dataref, false);
   v8::internal::AccountingAllocator allocator;
-  WasmModule module1_(std::make_unique<Zone>(&allocator, ZONE_NAME));
-  WasmModule module2_(std::make_unique<Zone>(&allocator, ZONE_NAME));
+  WasmModule module1_;
+  WasmModule module2_;
 
   WasmModule* module1 = &module1_;
   WasmModule* module2 = &module2_;

tools/wasm/module-inspector.cc

@@ -381,7 +381,6 @@ class HexDumpModuleDis {
         module_(module),
         names_(names),
         wire_bytes_(wire_bytes),
-        allocator_(allocator),
         zone_(allocator, "disassembler") {}
 
   // Public entrypoint.
@@ -394,8 +393,7 @@ class HexDumpModuleDis {
     std::unique_ptr<WasmModule> fake_module;
     std::unique_ptr<NamesProvider> names_provider;
     if (!names_) {
-      fake_module.reset(
-          new WasmModule(std::make_unique<Zone>(allocator_, "fake module")));
+      fake_module.reset(new WasmModule());
       names_provider.reset(
           new NamesProvider(fake_module.get(), wire_bytes_.module_bytes()));
       names_ = names_provider.get();
@@ -701,7 +699,6 @@ class HexDumpModuleDis {
   const WasmModule* module_;
   NamesProvider* names_;
   const ModuleWireBytes wire_bytes_;
-  AccountingAllocator* allocator_;
   Zone zone_;
 
   StringBuilder description_;