// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <memory>

#include "src/objects-inl.h"
#include "src/wasm/function-compiler.h"
#include "src/wasm/wasm-engine.h"
#include "src/wasm/wasm-module-builder.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-objects-inl.h"

#include "test/cctest/cctest.h"
#include "test/common/wasm/test-signatures.h"
#include "test/common/wasm/wasm-macro-gen.h"
#include "test/common/wasm/wasm-module-runner.h"

namespace v8 {
namespace internal {
namespace wasm {
namespace test_wasm_shared_engine {

// Helper class representing a WebAssembly engine that is capable of being
// shared between multiple Isolates, sharing the underlying generated code.
class SharedEngine {
 public:
  explicit SharedEngine(size_t max_committed = kMaxWasmCodeMemory)
      : wasm_engine_(base::make_unique<WasmEngine>()) {}
  ~SharedEngine() {
    // Ensure no remaining uses exist.
    CHECK(wasm_engine_.unique());
  }

  WasmEngine* engine() const { return wasm_engine_.get(); }
  WasmCodeManager* code_manager() const { return engine()->code_manager(); }

  int NumberOfExportedEngineUses() const {
    // This class holds one implicit use itself, which we discount.
    return static_cast<int>(wasm_engine_.use_count()) - 1;
  }

  std::shared_ptr<WasmEngine> ExportEngineForSharing() { return wasm_engine_; }

 private:
  std::shared_ptr<WasmEngine> wasm_engine_;
};

// Helper type definition representing a WebAssembly module shared between
// multiple Isolates with implicit reference counting.
using SharedModule = std::shared_ptr<NativeModule>;

// Helper class representing an Isolate based on a given shared WebAssembly
// engine available at construction time.
class SharedEngineIsolate {
 public:
  explicit SharedEngineIsolate(SharedEngine* engine)
      : isolate_(v8::Isolate::Allocate()) {
    isolate()->SetWasmEngine(engine->ExportEngineForSharing());
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate::Initialize(isolate_, create_params);
    v8::HandleScope handle_scope(v8_isolate());
    v8::Context::New(v8_isolate())->Enter();
    testing::SetupIsolateForWasmModule(isolate());
    zone_.reset(new Zone(isolate()->allocator(), ZONE_NAME));
  }
  ~SharedEngineIsolate() {
    zone_.reset();
    isolate_->Dispose();
  }

  Zone* zone() const { return zone_.get(); }
  v8::Isolate* v8_isolate() { return isolate_; }
  Isolate* isolate() { return reinterpret_cast<Isolate*>(isolate_); }

  Handle<WasmInstanceObject> CompileAndInstantiate(ZoneBuffer* buffer) {
    ErrorThrower thrower(isolate(), "CompileAndInstantiate");
    MaybeHandle<WasmInstanceObject> instance =
        testing::CompileAndInstantiateForTesting(
            isolate(), &thrower,
            ModuleWireBytes(buffer->begin(), buffer->end()));
    return instance.ToHandleChecked();
  }

  Handle<WasmInstanceObject> ImportInstance(SharedModule shared_module) {
    Handle<WasmModuleObject> module_object =
        isolate()->wasm_engine()->ImportNativeModule(isolate(), shared_module);
    ErrorThrower thrower(isolate(), "ImportInstance");
    MaybeHandle<WasmInstanceObject> instance =
        isolate()->wasm_engine()->SyncInstantiate(isolate(), &thrower,
                                                  module_object, {}, {});
    return instance.ToHandleChecked();
  }

  SharedModule ExportInstance(Handle<WasmInstanceObject> instance) {
    return instance->module_object()->managed_native_module()->get();
  }

  int32_t Run(Handle<WasmInstanceObject> instance) {
    return testing::RunWasmModuleForTesting(isolate(), instance, 0, nullptr);
  }

 private:
  v8::Isolate* isolate_;
  std::unique_ptr<Zone> zone_;
};

// Helper class representing a Thread running its own instance of an Isolate
// with a shared WebAssembly engine available at construction time.
class SharedEngineThread : public v8::base::Thread {
 public:
  SharedEngineThread(SharedEngine* engine,
                     std::function<void(SharedEngineIsolate&)> callback)
      : Thread(Options("SharedEngineThread")),
        engine_(engine),
        callback_(callback) {}

  void Run() override {
    SharedEngineIsolate isolate(engine_);
    callback_(isolate);
  }

 private:
  SharedEngine* engine_;
  std::function<void(SharedEngineIsolate&)> callback_;
};

namespace {

ZoneBuffer* BuildReturnConstantModule(Zone* zone, int constant) {
  TestSignatures sigs;
  ZoneBuffer* buffer = new (zone) ZoneBuffer(zone);
  WasmModuleBuilder* builder = new (zone) WasmModuleBuilder(zone);
  WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
  f->builder()->AddExport(CStrVector("main"), f);
  byte code[] = {WASM_I32V_2(constant)};
  f->EmitCode(code, sizeof(code));
  f->Emit(kExprEnd);
  builder->WriteTo(*buffer);
  return buffer;
}

class MockInstantiationResolver : public InstantiationResultResolver {
 public:
  explicit MockInstantiationResolver(Handle<Object>* out_instance)
      : out_instance_(out_instance) {}
  void OnInstantiationSucceeded(Handle<WasmInstanceObject> result) override {
    *out_instance_->location() = *result;
  }
  void OnInstantiationFailed(Handle<Object> error_reason) override {
    UNREACHABLE();
  }

 private:
  Handle<Object>* out_instance_;
};

class MockCompilationResolver : public CompilationResultResolver {
 public:
  MockCompilationResolver(SharedEngineIsolate& isolate,
                          Handle<Object>* out_instance)
      : isolate_(isolate), out_instance_(out_instance) {}
  void OnCompilationSucceeded(Handle<WasmModuleObject> result) override {
    isolate_.isolate()->wasm_engine()->AsyncInstantiate(
        isolate_.isolate(),
        base::make_unique<MockInstantiationResolver>(out_instance_), result,
        {});
  }
  void OnCompilationFailed(Handle<Object> error_reason) override {
    UNREACHABLE();
  }

 private:
  SharedEngineIsolate& isolate_;
  Handle<Object>* out_instance_;
};

void PumpMessageLoop(SharedEngineIsolate& isolate) {
  v8::platform::PumpMessageLoop(i::V8::GetCurrentPlatform(),
                                isolate.v8_isolate(),
                                platform::MessageLoopBehavior::kWaitForWork);
  isolate.isolate()->RunMicrotasks();
}

Handle<WasmInstanceObject> CompileAndInstantiateAsync(
    SharedEngineIsolate& isolate, ZoneBuffer* buffer) {
  Handle<Object> maybe_instance = handle(Smi::kZero, isolate.isolate());
  auto enabled_features = WasmFeaturesFromIsolate(isolate.isolate());
  isolate.isolate()->wasm_engine()->AsyncCompile(
      isolate.isolate(), enabled_features,
      base::make_unique<MockCompilationResolver>(isolate, &maybe_instance),
      ModuleWireBytes(buffer->begin(), buffer->end()), true);
  while (!maybe_instance->IsWasmInstanceObject()) PumpMessageLoop(isolate);
  Handle<WasmInstanceObject> instance =
      Handle<WasmInstanceObject>::cast(maybe_instance);
  return instance;
}

}  // namespace

TEST(SharedEngineUseCount) {
  SharedEngine engine;
  CHECK_EQ(0, engine.NumberOfExportedEngineUses());
  {
    SharedEngineIsolate isolate(&engine);
    CHECK_EQ(1, engine.NumberOfExportedEngineUses());
  }
  CHECK_EQ(0, engine.NumberOfExportedEngineUses());
  {
    SharedEngineIsolate isolate1(&engine);
    CHECK_EQ(1, engine.NumberOfExportedEngineUses());
    SharedEngineIsolate isolate2(&engine);
    CHECK_EQ(2, engine.NumberOfExportedEngineUses());
  }
  CHECK_EQ(0, engine.NumberOfExportedEngineUses());
}

TEST(SharedEngineRunSeparated) {
  SharedEngine engine;
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    CHECK_EQ(23, isolate.Run(instance));
  }
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 42);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    CHECK_EQ(42, isolate.Run(instance));
  }
}

TEST(SharedEngineRunImported) {
  SharedEngine engine;
  SharedModule module;
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    module = isolate.ExportInstance(instance);
    CHECK_EQ(23, isolate.Run(instance));
    CHECK_EQ(2, module.use_count());
  }
  CHECK_EQ(1, module.use_count());
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
    CHECK_EQ(23, isolate.Run(instance));
    CHECK_EQ(2, module.use_count());
  }
  CHECK_EQ(1, module.use_count());
}

TEST(SharedEngineRunThreadedBuildingSync) {
  SharedEngine engine;
  SharedEngineThread thread1(&engine, [](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    CHECK_EQ(23, isolate.Run(instance));
  });
  SharedEngineThread thread2(&engine, [](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 42);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    CHECK_EQ(42, isolate.Run(instance));
  });
  thread1.Start();
  thread2.Start();
  thread1.Join();
  thread2.Join();
}

TEST(SharedEngineRunThreadedBuildingAsync) {
  SharedEngine engine;
  SharedEngineThread thread1(&engine, [](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance =
        CompileAndInstantiateAsync(isolate, buffer);
    CHECK_EQ(23, isolate.Run(instance));
  });
  SharedEngineThread thread2(&engine, [](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 42);
    Handle<WasmInstanceObject> instance =
        CompileAndInstantiateAsync(isolate, buffer);
    CHECK_EQ(42, isolate.Run(instance));
  });
  thread1.Start();
  thread2.Start();
  thread1.Join();
  thread2.Join();
}

TEST(SharedEngineRunThreadedExecution) {
  SharedEngine engine;
  SharedModule module;
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    module = isolate.ExportInstance(instance);
  }
  SharedEngineThread thread1(&engine, [module](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
    CHECK_EQ(23, isolate.Run(instance));
  });
  SharedEngineThread thread2(&engine, [module](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
    CHECK_EQ(23, isolate.Run(instance));
  });
  thread1.Start();
  thread2.Start();
  thread1.Join();
  thread2.Join();
}

TEST(SharedEngineRunThreadedTierUp) {
  SharedEngine engine;
  SharedModule module;
  {
    SharedEngineIsolate isolate(&engine);
    HandleScope scope(isolate.isolate());
    ZoneBuffer* buffer = BuildReturnConstantModule(isolate.zone(), 23);
    Handle<WasmInstanceObject> instance = isolate.CompileAndInstantiate(buffer);
    module = isolate.ExportInstance(instance);
  }
  constexpr int kNumberOfThreads = 5;
  std::list<SharedEngineThread> threads;
  for (int i = 0; i < kNumberOfThreads; ++i) {
    threads.emplace_back(&engine, [module](SharedEngineIsolate& isolate) {
      constexpr int kNumberOfIterations = 100;
      HandleScope scope(isolate.isolate());
      Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
      for (int j = 0; j < kNumberOfIterations; ++j) {
        CHECK_EQ(23, isolate.Run(instance));
      }
    });
  }
  threads.emplace_back(&engine, [module](SharedEngineIsolate& isolate) {
    HandleScope scope(isolate.isolate());
    Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
    WasmFeatures detected = kNoWasmFeatures;
    WasmCompilationUnit::CompileWasmFunction(
        isolate.isolate(), module.get(), &detected,
        &module->module()->functions[0], ExecutionTier::kOptimized);
    CHECK_EQ(23, isolate.Run(instance));
  });
  for (auto& thread : threads) thread.Start();
  for (auto& thread : threads) thread.Join();
}

}  // namespace test_wasm_shared_engine
}  // namespace wasm
}  // namespace internal
}  // namespace v8