[wasm] Add size estimates for managed objects

This CL estimates the sizes of the important managed objects in WASM:
the decoded module {WasmModule}, the native module that contains code
{NativeModule}, and the natively-allocated indirect and import tables
{WasmInstanceNativeAllocations}.

Since Managed<T> updates the isolate's external allocated memory,
it is no longer necessary to do so upon committing or releasing a
native module's memory.

R=mstarzinger@chromium.org
CC=ulan@chromium.org

Bug: v8:7424
Change-Id: Iff4e07d0d328383a925febd654ccbfc95f0930e9
Reviewed-on: https://chromium-review.googlesource.com/1079067
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53675}

src/wasm/module-compiler.cc

@@ -1370,7 +1370,7 @@ MaybeHandle<WasmModuleObject> CompileToModuleObjectInternal(
 
   // The {managed_module} will take ownership of the {WasmModule} object,
   // and it will be destroyed when the GC reclaims the wrapper object.
-  size_t module_size = 0;  // TODO(titzer): estimate size of decoded module.
+  size_t module_size = EstimateWasmModuleSize(module.get());
   Handle<Managed<WasmModule>> managed_module =
       Managed<WasmModule>::FromUniquePtr(isolate, module_size,
                                          std::move(module));
@@ -2901,7 +2901,7 @@ void AsyncCompileJob::FinishCompile() {
 
   // The {managed_module} will take ownership of the {WasmModule} object,
   // and it will be destroyed when the GC reclaims the wrapper object.
-  size_t module_size = 0;  // TODO(titzer): estimate size of decoded module.
+  size_t module_size = EstimateWasmModuleSize(module_.get());
   Handle<Managed<WasmModule>> managed_module =
       Managed<WasmModule>::FromUniquePtr(isolate_, module_size,
                                          std::move(module_));

src/wasm/wasm-code-manager.cc

@@ -885,8 +885,6 @@ bool WasmCodeManager::Commit(Address start, size_t size) {
     remaining_uncommitted_code_space_.fetch_add(size);
     return false;
   }
-  // This API assumes main thread
-  isolate_->AdjustAmountOfExternalAllocatedMemory(size);
   if (WouldGCHelp()) {
     // This API does not assume main thread, and would schedule
     // a GC if called from a different thread, instead of synchronously
@@ -927,34 +925,39 @@ void WasmCodeManager::TryAllocate(size_t size, VirtualMemory* ret, void* hint) {
              reinterpret_cast<void*>(ret->end()), ret->size());
 }
 
-size_t WasmCodeManager::GetAllocationChunk(const WasmModule& module) {
-  // TODO(mtrofin): this should pick up its 'maximal code range size'
-  // from something embedder-provided
-  if (kRequiresCodeRange) return kMaxWasmCodeMemory;
-  DCHECK(kModuleCanAllocateMoreMemory);
-  size_t ret = AllocatePageSize();
-  // a ballpark guesstimate on native inflation factor.
-  constexpr size_t kMultiplier = 4;
-
-  for (auto& function : module.functions) {
-    ret += kMultiplier * function.code.length();
+size_t WasmCodeManager::EstimateNativeModuleSize(const WasmModule* module) {
+  constexpr size_t kCodeSizeMultiplier = 4;
+  constexpr size_t kImportSize = 32 * kPointerSize;
+
+  size_t estimate =
+      AllocatePageSize() /* TODO(titzer): 1 page spot bonus */ +
+      sizeof(NativeModule) +
+      (sizeof(WasmCode*) * module->functions.size() /* code table size */) +
+      (sizeof(WasmCode) * module->functions.size() /* code object size */) +
+      (kImportSize * module->num_imported_functions /* import size */);
+
+  for (auto& function : module->functions) {
+    estimate += kCodeSizeMultiplier * function.code.length();
   }
-  return ret;
+
+  return estimate;
 }
 
 std::unique_ptr<NativeModule> WasmCodeManager::NewNativeModule(
     const WasmModule& module, ModuleEnv& env) {
-  size_t code_size = GetAllocationChunk(module);
+  size_t memory_estimate = EstimateNativeModuleSize(&module);
   return NewNativeModule(
-      code_size, static_cast<uint32_t>(module.functions.size()),
+      memory_estimate, static_cast<uint32_t>(module.functions.size()),
       module.num_imported_functions, kModuleCanAllocateMoreMemory, env);
 }
 
 std::unique_ptr<NativeModule> WasmCodeManager::NewNativeModule(
-    size_t size_estimate, uint32_t num_functions,
+    size_t memory_estimate, uint32_t num_functions,
     uint32_t num_imported_functions, bool can_request_more, ModuleEnv& env) {
   VirtualMemory mem;
-  TryAllocate(size_estimate, &mem);
+  // If the code must be contiguous, reserve enough address space up front.
+  size_t vmem_size = kRequiresCodeRange ? kMaxWasmCodeMemory : memory_estimate;
+  TryAllocate(vmem_size, &mem);
   if (mem.IsReserved()) {
     Address start = mem.address();
     size_t size = mem.size();
@@ -1041,8 +1044,6 @@ void WasmCodeManager::FreeNativeModule(NativeModule* native_module) {
   // which we currently indicate by having the isolate_ as null
   if (isolate_ == nullptr) return;
   remaining_uncommitted_code_space_.fetch_add(code_size);
-  isolate_->AdjustAmountOfExternalAllocatedMemory(
-      -static_cast<int64_t>(code_size));
 }
 
 // TODO(wasm): We can make this more efficient if needed. For

src/wasm/wasm-code-manager.h

@@ -439,6 +439,7 @@ class V8_EXPORT_PRIVATE WasmCodeManager final {
   void SetModuleCodeSizeHistogram(Histogram* histogram) {
     module_code_size_mb_ = histogram;
   }
+  static size_t EstimateNativeModuleSize(const WasmModule* module);
 
  private:
   friend class NativeModule;
@@ -452,7 +453,6 @@ class V8_EXPORT_PRIVATE WasmCodeManager final {
   void FreeNativeModule(NativeModule*);
   void Free(VirtualMemory* mem);
   void AssignRanges(Address start, Address end, NativeModule*);
-  size_t GetAllocationChunk(const WasmModule& module);
   bool WouldGCHelp() const;
 
   std::map<Address, std::pair<Address, NativeModule*>> lookup_map_;

src/wasm/wasm-module.cc

@@ -341,6 +341,24 @@ Handle<FixedArray> DecodeLocalNames(Isolate* isolate,
   }
   return locals_names;
 }
+
+namespace {
+template <typename T>
+inline size_t VectorSize(const std::vector<T>& vector) {
+  return sizeof(T) * vector.size();
+}
+}  // namespace
+
+size_t EstimateWasmModuleSize(const WasmModule* module) {
+  size_t estimate =
+      sizeof(WasmModule) + VectorSize(module->signatures) +
+      VectorSize(module->signature_ids) + VectorSize(module->functions) +
+      VectorSize(module->data_segments) + VectorSize(module->function_tables) +
+      VectorSize(module->import_table) + VectorSize(module->export_table) +
+      VectorSize(module->exceptions) + VectorSize(module->table_inits);
+  // TODO(wasm): include names table and wire bytes in size estimate
+  return estimate;
+}
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8

src/wasm/wasm-module.h

@@ -180,6 +180,8 @@ struct V8_EXPORT_PRIVATE WasmModule {
   void AddNameForTesting(int function_index, WireBytesRef name);
 };
 
+size_t EstimateWasmModuleSize(const WasmModule* module);
+
 // Interface to the storage (wire bytes) of a wasm module.
 // It is illegal for anyone receiving a ModuleWireBytes to store pointers based
 // on module_bytes, as this storage is only guaranteed to be alive as long as

src/wasm/wasm-objects.cc

@@ -127,6 +127,16 @@ class WasmInstanceNativeAllocations {
 #undef SET
 };
 
+size_t EstimateNativeAllocationsSize(const WasmModule* module) {
+  size_t estimate = sizeof(WasmInstanceNativeAllocations) +
+                    (1 * kPointerSize * module->num_imported_mutable_globals) +
+                    (2 * kPointerSize * module->num_imported_functions);
+  for (auto& table : module->function_tables) {
+    estimate += 3 * kPointerSize * table.initial_size;
+  }
+  return estimate;
+}
+
 WasmInstanceNativeAllocations* GetNativeAllocations(
     WasmInstanceObject* instance) {
   return reinterpret_cast<Managed<WasmInstanceNativeAllocations>*>(
@@ -811,11 +821,10 @@ Handle<WasmInstanceObject> WasmInstanceObject::New(
       reinterpret_cast<WasmInstanceObject*>(*instance_object), isolate);
 
   // Initialize the imported function arrays.
-  auto num_imported_functions =
-      module_object->shared()->module()->num_imported_functions;
-  auto num_imported_mutable_globals =
-      module_object->shared()->module()->num_imported_mutable_globals;
-  size_t native_allocations_size = 0;  // TODO(titzer): estimate properly.
+  auto module = module_object->shared()->module();
+  auto num_imported_functions = module->num_imported_functions;
+  auto num_imported_mutable_globals = module->num_imported_mutable_globals;
+  size_t native_allocations_size = EstimateNativeAllocationsSize(module);
   auto native_allocations = Managed<WasmInstanceNativeAllocations>::Allocate(
       isolate, native_allocations_size, instance, num_imported_functions,
       num_imported_mutable_globals);
@@ -1388,12 +1397,13 @@ Handle<WasmCompiledModule> WasmCompiledModule::New(Isolate* isolate,
       isolate->factory()->NewStruct(WASM_COMPILED_MODULE_TYPE, TENURED));
   compiled_module->set_weak_owning_instance(isolate->heap()->empty_weak_cell());
   {
+    size_t memory_estimate =
+        isolate->wasm_engine()->code_manager()->EstimateNativeModuleSize(
+            module);
     auto native_module =
         isolate->wasm_engine()->code_manager()->NewNativeModule(*module, env);
-    size_t native_module_size =
-        0;  // TODO(titzer): estimate native module size.
     Handle<Foreign> native_module_wrapper =
-        Managed<wasm::NativeModule>::FromUniquePtr(isolate, native_module_size,
+        Managed<wasm::NativeModule>::FromUniquePtr(isolate, memory_estimate,
                                                    std::move(native_module));
     compiled_module->set_native_module(*native_module_wrapper);
   }

src/wasm/wasm-serialization.cc

@@ -591,8 +591,8 @@ MaybeHandle<WasmModuleObject> DeserializeNativeModule(
           .ToHandleChecked();
   DCHECK(module_bytes->IsSeqOneByteString());
   // The {managed_module} will take ownership of the {WasmModule} object,
-  // and it will be destroyed when the GC reclaims the wrapper object.
-  size_t module_size = 0;  // TODO(titzer): estimate size properly.
+  // and it will be destroyed when the GC reclaims it.
+  size_t module_size = EstimateWasmModuleSize(decode_result.val.get());
   Handle<Managed<WasmModule>> managed_module =
       Managed<WasmModule>::FromUniquePtr(isolate, module_size,
                                          std::move(decode_result.val));

test/unittests/wasm/wasm-code-manager-unittest.cc

@@ -255,7 +255,7 @@ TEST_P(WasmCodeManagerTest, GrowingVsFixedModule) {
   WasmCodeManager manager(v8_isolate(), 3 * page());
   NativeModulePtr nm = AllocModule(&manager, 1 * page(), GetParam());
   if (GetParam() == Fixed) {
-    ASSERT_DEATH_IF_SUPPORTED(AddCode(nm.get(), 0, 1 * page() + kCodeAlignment),
+    ASSERT_DEATH_IF_SUPPORTED(AddCode(nm.get(), 0, kMaxWasmCodeMemory + 1),
                               "OOM in NativeModule::AddOwnedCode");
   } else {
     CHECK_NOT_NULL(AddCode(nm.get(), 0, 1 * page() + kCodeAlignment));