src/v8/test/cctest/test-lockers.cc

// Copyright 2007-2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <limits.h>

#include <memory>

#include "src/init/v8.h"

#include "src/base/platform/platform.h"
#include "src/codegen/compilation-cache.h"
#include "src/execution/execution.h"
#include "src/execution/isolate.h"
#include "src/objects/objects-inl.h"
#include "src/strings/unicode-inl.h"
#include "src/utils/utils.h"
#include "test/cctest/cctest.h"

namespace {

class DeoptimizeCodeThread : public v8::base::Thread {
 public:
  DeoptimizeCodeThread(v8::Isolate* isolate, v8::Local<v8::Context> context,
                       const char* trigger)
      : Thread(Options("DeoptimizeCodeThread")),
        isolate_(isolate),
        context_(isolate, context),
        source_(trigger) {}

  void Run() override {
    v8::Locker locker(isolate_);
    isolate_->Enter();
    v8::HandleScope handle_scope(isolate_);
    v8::Local<v8::Context> context =
        v8::Local<v8::Context>::New(isolate_, context_);
    v8::Context::Scope context_scope(context);
    // This code triggers deoptimization of some function that will be
    // used in a different thread.
    CompileRun(source_);
    isolate_->Exit();
  }

 private:
  v8::Isolate* isolate_;
  v8::Persistent<v8::Context> context_;
  // The code that triggers the deoptimization.
  const char* source_;
};

void UnlockForDeoptimization(const v8::FunctionCallbackInfo<v8::Value>& args) {
  v8::Isolate* isolate = args.GetIsolate();
  // Gets the pointer to the thread that will trigger the deoptimization of the
  // code.
  DeoptimizeCodeThread* deoptimizer =
      reinterpret_cast<DeoptimizeCodeThread*>(isolate->GetData(0));
  {
    // Exits and unlocks the isolate.
    isolate->Exit();
    v8::Unlocker unlocker(isolate);
    // Starts the deoptimizing thread.
    deoptimizer->Start();
    // Waits for deoptimization to finish.
    deoptimizer->Join();
  }
  // The deoptimizing thread has finished its work, and the isolate
  // will now be used by the current thread.
  isolate->Enter();
}

void UnlockForDeoptimizationIfReady(
    const v8::FunctionCallbackInfo<v8::Value>& args) {
  v8::Isolate* isolate = args.GetIsolate();
  bool* ready_to_deoptimize = reinterpret_cast<bool*>(isolate->GetData(1));
  if (*ready_to_deoptimize) {
    // The test should enter here only once, so put the flag back to false.
    *ready_to_deoptimize = false;
    // Gets the pointer to the thread that will trigger the deoptimization of
    // the code.
    DeoptimizeCodeThread* deoptimizer =
        reinterpret_cast<DeoptimizeCodeThread*>(isolate->GetData(0));
    {
      // Exits and unlocks the thread.
      isolate->Exit();
      v8::Unlocker unlocker(isolate);
      // Starts the thread that deoptimizes the function.
      deoptimizer->Start();
      // Waits for the deoptimizing thread to finish.
      deoptimizer->Join();
    }
    // The deoptimizing thread has finished its work, and the isolate
    // will now be used by the current thread.
    isolate->Enter();
  }
}
}  // namespace

namespace v8 {
namespace internal {
namespace test_lockers {

TEST(LazyDeoptimizationMultithread) {
  i::FLAG_allow_natives_syntax = true;
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  {
    v8::Locker locker(isolate);
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope scope(isolate);
    v8::Local<v8::Context> context = v8::Context::New(isolate);
    const char* trigger_deopt = "obj = { y: 0, x: 1 };";

    // We use the isolate to pass arguments to the UnlockForDeoptimization
    // function. Namely, we pass a pointer to the deoptimizing thread.
    DeoptimizeCodeThread deoptimize_thread(isolate, context, trigger_deopt);
    isolate->SetData(0, &deoptimize_thread);
    v8::Context::Scope context_scope(context);

    // Create the function templace for C++ code that is invoked from
    // JavaScript code.
    Local<v8::FunctionTemplate> fun_templ =
        v8::FunctionTemplate::New(isolate, UnlockForDeoptimization);
    Local<Function> fun = fun_templ->GetFunction(context).ToLocalChecked();
    CHECK(context->Global()
              ->Set(context, v8_str("unlock_for_deoptimization"), fun)
              .FromJust());

    // Optimizes a function f, which will be deoptimized in another
    // thread.
    CompileRun(
        "var b = false; var obj = { x: 1 };"
        "function f() { g(); return obj.x; }"
        "function g() { if (b) { unlock_for_deoptimization(); } }"
        "%NeverOptimizeFunction(g);"
        "%PrepareFunctionForOptimization(f);"
        "f(); f(); %OptimizeFunctionOnNextCall(f);"
        "f();");

    // Trigger the unlocking.
    Local<Value> v = CompileRun("b = true; f();");

    // Once the isolate has been unlocked, the thread will wait for the
    // other thread to finish its task. Once this happens, this thread
    // continues with its execution, that is, with the execution of the
    // function g, which then returns to f. The function f should have
    // also been deoptimized. If the replacement did not happen on this
    // thread's stack, then the test will fail here.
    CHECK(v->IsNumber());
    CHECK_EQ(1, static_cast<int>(v->NumberValue(context).FromJust()));
  }
  isolate->Dispose();
}

TEST(LazyDeoptimizationMultithreadWithNatives) {
  i::FLAG_allow_natives_syntax = true;
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  {
    v8::Locker locker(isolate);
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope scope(isolate);
    v8::Local<v8::Context> context = v8::Context::New(isolate);
    const char* trigger_deopt = "%DeoptimizeFunction(f);";

    // We use the isolate to pass arguments to the UnlockForDeoptimization
    // function. Namely, we pass a pointer to the deoptimizing thread.
    DeoptimizeCodeThread deoptimize_thread(isolate, context, trigger_deopt);
    isolate->SetData(0, &deoptimize_thread);
    bool ready_to_deopt = false;
    isolate->SetData(1, &ready_to_deopt);
    v8::Context::Scope context_scope(context);

    // Create the function templace for C++ code that is invoked from
    // JavaScript code.
    Local<v8::FunctionTemplate> fun_templ =
        v8::FunctionTemplate::New(isolate, UnlockForDeoptimizationIfReady);
    Local<Function> fun = fun_templ->GetFunction(context).ToLocalChecked();
    CHECK(context->Global()
              ->Set(context, v8_str("unlock_for_deoptimization"), fun)
              .FromJust());

    // Optimizes a function f, which will be deoptimized in another
    // thread.
    CompileRun(
        "var obj = { x: 1 };"
        "function f() { g(); return obj.x;}"
        "function g() { "
        "  unlock_for_deoptimization(); }"
        "%NeverOptimizeFunction(g);"
        "%PrepareFunctionForOptimization(f);"
        "f(); f(); %OptimizeFunctionOnNextCall(f);");

    // Trigger the unlocking.
    ready_to_deopt = true;
    isolate->SetData(1, &ready_to_deopt);
    Local<Value> v = CompileRun("f();");

    // Once the isolate has been unlocked, the thread will wait for the
    // other thread to finish its task. Once this happens, this thread
    // continues with its execution, that is, with the execution of the
    // function g, which then returns to f. The function f should have
    // also been deoptimized. Otherwise, the test will fail here.
    CHECK(v->IsNumber());
    CHECK_EQ(1, static_cast<int>(v->NumberValue(context).FromJust()));
  }
  isolate->Dispose();
}

TEST(EagerDeoptimizationMultithread) {
  i::FLAG_allow_natives_syntax = true;
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  {
    v8::Locker locker(isolate);
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope scope(isolate);
    v8::Local<v8::Context> context = v8::Context::New(isolate);
    const char* trigger_deopt = "f({y: 0, x: 1});";

    // We use the isolate to pass arguments to the UnlockForDeoptimization
    // function. Namely, we pass a pointer to the deoptimizing thread.
    DeoptimizeCodeThread deoptimize_thread(isolate, context, trigger_deopt);
    isolate->SetData(0, &deoptimize_thread);
    bool ready_to_deopt = false;
    isolate->SetData(1, &ready_to_deopt);
    v8::Context::Scope context_scope(context);

    // Create the function templace for C++ code that is invoked from
    // JavaScript code.
    Local<v8::FunctionTemplate> fun_templ =
        v8::FunctionTemplate::New(isolate, UnlockForDeoptimizationIfReady);
    Local<Function> fun = fun_templ->GetFunction(context).ToLocalChecked();
    CHECK(context->Global()
              ->Set(context, v8_str("unlock_for_deoptimization"), fun)
              .FromJust());

    // Optimizes a function f, which will be deoptimized by another thread.
    CompileRun(
        "function f(obj) { unlock_for_deoptimization(); return obj.x; }"
        "%PrepareFunctionForOptimization(f);"
        "f({x: 1}); f({x: 1});"
        "%OptimizeFunctionOnNextCall(f);"
        "f({x: 1});");

    // Trigger the unlocking.
    ready_to_deopt = true;
    isolate->SetData(1, &ready_to_deopt);
    Local<Value> v = CompileRun("f({x: 1});");

    // Once the isolate has been unlocked, the thread will wait for the
    // other thread to finish its task. Once this happens, this thread
    // continues with its execution, that is, with the execution of the
    // function g, which then returns to f. The function f should have
    // also been deoptimized. Otherwise, the test will fail here.
    CHECK(v->IsNumber());
    CHECK_EQ(1, static_cast<int>(v->NumberValue(context).FromJust()));
  }
  isolate->Dispose();
}

// Migrating an isolate
class KangarooThread : public v8::base::Thread {
 public:
  KangarooThread(v8::Isolate* isolate, v8::Local<v8::Context> context)
      : Thread(Options("KangarooThread")),
        isolate_(isolate),
        context_(isolate, context) {}

  void Run() override {
    {
      v8::Locker locker(isolate_);
      v8::Isolate::Scope isolate_scope(isolate_);
      v8::HandleScope scope(isolate_);
      v8::Local<v8::Context> context =
          v8::Local<v8::Context>::New(isolate_, context_);
      v8::Context::Scope context_scope(context);
      Local<Value> v = CompileRun("getValue()");
      CHECK(v->IsNumber());
      CHECK_EQ(30, static_cast<int>(v->NumberValue(context).FromJust()));
    }
    {
      v8::Locker locker(isolate_);
      v8::Isolate::Scope isolate_scope(isolate_);
      v8::HandleScope scope(isolate_);
      v8::Local<v8::Context> context =
          v8::Local<v8::Context>::New(isolate_, context_);
      v8::Context::Scope context_scope(context);
      Local<Value> v = CompileRun("getValue()");
      CHECK(v->IsNumber());
      CHECK_EQ(30, static_cast<int>(v->NumberValue(context).FromJust()));
    }
    isolate_->Dispose();
  }

 private:
  v8::Isolate* isolate_;
  v8::Persistent<v8::Context> context_;
};


// Migrates an isolate from one thread to another
TEST(KangarooIsolates) {
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  std::unique_ptr<KangarooThread> thread1;
  {
    v8::Locker locker(isolate);
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope handle_scope(isolate);
    v8::Local<v8::Context> context = v8::Context::New(isolate);
    v8::Context::Scope context_scope(context);
    CompileRun("function getValue() { return 30; }");
    thread1.reset(new KangarooThread(isolate, context));
  }
  thread1->Start();
  thread1->Join();
}


static void CalcFibAndCheck(v8::Local<v8::Context> context) {
  Local<Value> v = CompileRun("function fib(n) {"
                              "  if (n <= 2) return 1;"
                              "  return fib(n-1) + fib(n-2);"
                              "}"
                              "fib(10)");
  CHECK(v->IsNumber());
  CHECK_EQ(55, static_cast<int>(v->NumberValue(context).FromJust()));
}

class JoinableThread {
 public:
  explicit JoinableThread(const char* name)
    : name_(name),
      semaphore_(0),
      thread_(this) {
  }

  virtual ~JoinableThread() = default;

  void Start() {
    thread_.Start();
  }

  void Join() {
    semaphore_.Wait();
    thread_.Join();
  }

  virtual void Run() = 0;

 private:
  class ThreadWithSemaphore : public v8::base::Thread {
   public:
    explicit ThreadWithSemaphore(JoinableThread* joinable_thread)
        : Thread(Options(joinable_thread->name_)),
          joinable_thread_(joinable_thread) {}

    void Run() override {
      joinable_thread_->Run();
      joinable_thread_->semaphore_.Signal();
    }

   private:
    JoinableThread* joinable_thread_;
  };

  const char* name_;
  v8::base::Semaphore semaphore_;
  ThreadWithSemaphore thread_;

  friend class ThreadWithSemaphore;

  DISALLOW_COPY_AND_ASSIGN(JoinableThread);
};


class IsolateLockingThreadWithLocalContext : public JoinableThread {
 public:
  explicit IsolateLockingThreadWithLocalContext(v8::Isolate* isolate)
    : JoinableThread("IsolateLockingThread"),
      isolate_(isolate) {
  }

  void Run() override {
    v8::Locker locker(isolate_);
    v8::Isolate::Scope isolate_scope(isolate_);
    v8::HandleScope handle_scope(isolate_);
    LocalContext local_context(isolate_);
    CalcFibAndCheck(local_context.local());
  }
 private:
  v8::Isolate* isolate_;
};

static void StartJoinAndDeleteThreads(
    const std::vector<JoinableThread*>& threads) {
  for (const auto& thread : threads) {
    thread->Start();
  }
  for (const auto& thread : threads) {
    thread->Join();
  }
  for (const auto& thread : threads) {
    delete thread;
  }
}


// Run many threads all locking on the same isolate
TEST(IsolateLockingStress) {
  i::FLAG_always_opt = false;
#if V8_TARGET_ARCH_MIPS
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(new IsolateLockingThreadWithLocalContext(isolate));
  }
  StartJoinAndDeleteThreads(threads);
  isolate->Dispose();
}


class IsolateNestedLockingThread : public JoinableThread {
 public:
  explicit IsolateNestedLockingThread(v8::Isolate* isolate)
    : JoinableThread("IsolateNestedLocking"), isolate_(isolate) {
  }
  void Run() override {
    v8::Locker lock(isolate_);
    v8::Isolate::Scope isolate_scope(isolate_);
    v8::HandleScope handle_scope(isolate_);
    LocalContext local_context(isolate_);
    {
      v8::Locker another_lock(isolate_);
      CalcFibAndCheck(local_context.local());
    }
    {
      v8::Locker another_lock(isolate_);
      CalcFibAndCheck(local_context.local());
    }
  }
 private:
  v8::Isolate* isolate_;
};


// Run  many threads with nested locks
TEST(IsolateNestedLocking) {
  i::FLAG_always_opt = false;
#if V8_TARGET_ARCH_MIPS
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(new IsolateNestedLockingThread(isolate));
  }
  StartJoinAndDeleteThreads(threads);
  isolate->Dispose();
}


class SeparateIsolatesLocksNonexclusiveThread : public JoinableThread {
 public:
  SeparateIsolatesLocksNonexclusiveThread(v8::Isolate* isolate1,
                                          v8::Isolate* isolate2)
    : JoinableThread("SeparateIsolatesLocksNonexclusiveThread"),
      isolate1_(isolate1), isolate2_(isolate2) {
  }

  void Run() override {
    v8::Locker lock(isolate1_);
    v8::Isolate::Scope isolate_scope(isolate1_);
    v8::HandleScope handle_scope(isolate1_);
    LocalContext local_context(isolate1_);

    IsolateLockingThreadWithLocalContext threadB(isolate2_);
    threadB.Start();
    CalcFibAndCheck(local_context.local());
    threadB.Join();
  }
 private:
  v8::Isolate* isolate1_;
  v8::Isolate* isolate2_;
};


// Run parallel threads that lock and access different isolates in parallel
TEST(SeparateIsolatesLocksNonexclusive) {
  i::FLAG_always_opt = false;
#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_S390
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate1 = v8::Isolate::New(create_params);
  v8::Isolate* isolate2 = v8::Isolate::New(create_params);
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(
        new SeparateIsolatesLocksNonexclusiveThread(isolate1, isolate2));
  }
  StartJoinAndDeleteThreads(threads);
  isolate2->Dispose();
  isolate1->Dispose();
}

class LockIsolateAndCalculateFibSharedContextThread : public JoinableThread {
 public:
  explicit LockIsolateAndCalculateFibSharedContextThread(
      v8::Isolate* isolate, v8::Local<v8::Context> context)
      : JoinableThread("LockIsolateAndCalculateFibThread"),
        isolate_(isolate),
        context_(isolate, context) {}

  void Run() override {
    v8::Locker lock(isolate_);
    v8::Isolate::Scope isolate_scope(isolate_);
    v8::HandleScope handle_scope(isolate_);
    v8::Local<v8::Context> context =
        v8::Local<v8::Context>::New(isolate_, context_);
    v8::Context::Scope context_scope(context);
    CalcFibAndCheck(context);
  }
 private:
  v8::Isolate* isolate_;
  v8::Persistent<v8::Context> context_;
};

class LockerUnlockerThread : public JoinableThread {
 public:
  explicit LockerUnlockerThread(v8::Isolate* isolate)
    : JoinableThread("LockerUnlockerThread"),
      isolate_(isolate) {
  }

  void Run() override {
    isolate_->DiscardThreadSpecificMetadata();  // No-op
    {
      v8::Locker lock(isolate_);
      v8::Isolate::Scope isolate_scope(isolate_);
      v8::HandleScope handle_scope(isolate_);
      v8::Local<v8::Context> context = v8::Context::New(isolate_);
      {
        v8::Context::Scope context_scope(context);
        CalcFibAndCheck(context);
      }
      {
        LockIsolateAndCalculateFibSharedContextThread thread(isolate_, context);
        isolate_->Exit();
        v8::Unlocker unlocker(isolate_);
        thread.Start();
        thread.Join();
      }
      isolate_->Enter();
      {
        v8::Context::Scope context_scope(context);
        CalcFibAndCheck(context);
      }
    }
    isolate_->DiscardThreadSpecificMetadata();
    isolate_->DiscardThreadSpecificMetadata();  // No-op
  }

 private:
  v8::Isolate* isolate_;
};


// Use unlocker inside of a Locker, multiple threads.
TEST(LockerUnlocker) {
  i::FLAG_always_opt = false;
#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_S390
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(new LockerUnlockerThread(isolate));
  }
  StartJoinAndDeleteThreads(threads);
  isolate->Dispose();
}

class LockTwiceAndUnlockThread : public JoinableThread {
 public:
  explicit LockTwiceAndUnlockThread(v8::Isolate* isolate)
    : JoinableThread("LockTwiceAndUnlockThread"),
      isolate_(isolate) {
  }

  void Run() override {
    v8::Locker lock(isolate_);
    v8::Isolate::Scope isolate_scope(isolate_);
    v8::HandleScope handle_scope(isolate_);
    v8::Local<v8::Context> context = v8::Context::New(isolate_);
    {
      v8::Context::Scope context_scope(context);
      CalcFibAndCheck(context);
    }
    {
      v8::Locker second_lock(isolate_);
      {
        LockIsolateAndCalculateFibSharedContextThread thread(isolate_, context);
        isolate_->Exit();
        v8::Unlocker unlocker(isolate_);
        thread.Start();
        thread.Join();
      }
    }
    isolate_->Enter();
    {
      v8::Context::Scope context_scope(context);
      CalcFibAndCheck(context);
    }
  }

 private:
  v8::Isolate* isolate_;
};


// Use Unlocker inside two Lockers.
TEST(LockTwiceAndUnlock) {
  i::FLAG_always_opt = false;
#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_S390
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(new LockTwiceAndUnlockThread(isolate));
  }
  StartJoinAndDeleteThreads(threads);
  isolate->Dispose();
}

class LockAndUnlockDifferentIsolatesThread : public JoinableThread {
 public:
  LockAndUnlockDifferentIsolatesThread(v8::Isolate* isolate1,
                                       v8::Isolate* isolate2)
    : JoinableThread("LockAndUnlockDifferentIsolatesThread"),
      isolate1_(isolate1),
      isolate2_(isolate2) {
  }

  void Run() override {
    std::unique_ptr<LockIsolateAndCalculateFibSharedContextThread> thread;
    v8::Locker lock1(isolate1_);
    CHECK(v8::Locker::IsLocked(isolate1_));
    CHECK(!v8::Locker::IsLocked(isolate2_));
    {
      v8::Isolate::Scope isolate_scope(isolate1_);
      v8::HandleScope handle_scope(isolate1_);
      v8::Local<v8::Context> context1 = v8::Context::New(isolate1_);
      {
        v8::Context::Scope context_scope(context1);
        CalcFibAndCheck(context1);
      }
      thread.reset(new LockIsolateAndCalculateFibSharedContextThread(isolate1_,
                                                                     context1));
    }
    v8::Locker lock2(isolate2_);
    CHECK(v8::Locker::IsLocked(isolate1_));
    CHECK(v8::Locker::IsLocked(isolate2_));
    {
      v8::Isolate::Scope isolate_scope(isolate2_);
      v8::HandleScope handle_scope(isolate2_);
      v8::Local<v8::Context> context2 = v8::Context::New(isolate2_);
      {
        v8::Context::Scope context_scope(context2);
        CalcFibAndCheck(context2);
      }
      v8::Unlocker unlock1(isolate1_);
      CHECK(!v8::Locker::IsLocked(isolate1_));
      CHECK(v8::Locker::IsLocked(isolate2_));
      v8::Context::Scope context_scope(context2);
      thread->Start();
      CalcFibAndCheck(context2);
      thread->Join();
    }
  }

 private:
  v8::Isolate* isolate1_;
  v8::Isolate* isolate2_;
};


// Lock two isolates and unlock one of them.
TEST(LockAndUnlockDifferentIsolates) {
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate1 = v8::Isolate::New(create_params);
  v8::Isolate* isolate2 = v8::Isolate::New(create_params);
  LockAndUnlockDifferentIsolatesThread thread(isolate1, isolate2);
  thread.Start();
  thread.Join();
  isolate2->Dispose();
  isolate1->Dispose();
}

class LockUnlockLockThread : public JoinableThread {
 public:
  LockUnlockLockThread(v8::Isolate* isolate, v8::Local<v8::Context> context)
      : JoinableThread("LockUnlockLockThread"),
        isolate_(isolate),
        context_(isolate, context) {}

  void Run() override {
    v8::Locker lock1(isolate_);
    CHECK(v8::Locker::IsLocked(isolate_));
    CHECK(!v8::Locker::IsLocked(CcTest::isolate()));
    {
      v8::Isolate::Scope isolate_scope(isolate_);
      v8::HandleScope handle_scope(isolate_);
      v8::Local<v8::Context> context =
          v8::Local<v8::Context>::New(isolate_, context_);
      v8::Context::Scope context_scope(context);
      CalcFibAndCheck(context);
    }
    {
      v8::Unlocker unlock1(isolate_);
      CHECK(!v8::Locker::IsLocked(isolate_));
      CHECK(!v8::Locker::IsLocked(CcTest::isolate()));
      {
        v8::Locker lock2(isolate_);
        v8::Isolate::Scope isolate_scope(isolate_);
        v8::HandleScope handle_scope(isolate_);
        CHECK(v8::Locker::IsLocked(isolate_));
        CHECK(!v8::Locker::IsLocked(CcTest::isolate()));
        v8::Local<v8::Context> context =
            v8::Local<v8::Context>::New(isolate_, context_);
        v8::Context::Scope context_scope(context);
        CalcFibAndCheck(context);
      }
    }
  }

 private:
  v8::Isolate* isolate_;
  v8::Persistent<v8::Context> context_;
};


// Locker inside an Unlocker inside a Locker.
TEST(LockUnlockLockMultithreaded) {
#if V8_TARGET_ARCH_MIPS
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  {
    v8::Locker locker_(isolate);
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope handle_scope(isolate);
    v8::Local<v8::Context> context = v8::Context::New(isolate);
    for (int i = 0; i < kNThreads; i++) {
      threads.push_back(new LockUnlockLockThread(isolate, context));
    }
  }
  StartJoinAndDeleteThreads(threads);
  isolate->Dispose();
}

class LockUnlockLockDefaultIsolateThread : public JoinableThread {
 public:
  explicit LockUnlockLockDefaultIsolateThread(v8::Local<v8::Context> context)
      : JoinableThread("LockUnlockLockDefaultIsolateThread"),
        context_(CcTest::isolate(), context) {}

  void Run() override {
    v8::Locker lock1(CcTest::isolate());
    {
      v8::Isolate::Scope isolate_scope(CcTest::isolate());
      v8::HandleScope handle_scope(CcTest::isolate());
      v8::Local<v8::Context> context =
          v8::Local<v8::Context>::New(CcTest::isolate(), context_);
      v8::Context::Scope context_scope(context);
      CalcFibAndCheck(context);
    }
    {
      v8::Unlocker unlock1(CcTest::isolate());
      {
        v8::Locker lock2(CcTest::isolate());
        v8::Isolate::Scope isolate_scope(CcTest::isolate());
        v8::HandleScope handle_scope(CcTest::isolate());
        v8::Local<v8::Context> context =
            v8::Local<v8::Context>::New(CcTest::isolate(), context_);
        v8::Context::Scope context_scope(context);
        CalcFibAndCheck(context);
      }
    }
  }

 private:
  v8::Persistent<v8::Context> context_;
};


// Locker inside an Unlocker inside a Locker for default isolate.
TEST(LockUnlockLockDefaultIsolateMultithreaded) {
#if V8_TARGET_ARCH_MIPS
  const int kNThreads = 50;
#else
  const int kNThreads = 100;
#endif
  Local<v8::Context> context;
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  {
    v8::Locker locker_(CcTest::isolate());
    v8::Isolate::Scope isolate_scope(CcTest::isolate());
    v8::HandleScope handle_scope(CcTest::isolate());
    context = v8::Context::New(CcTest::isolate());
    for (int i = 0; i < kNThreads; i++) {
      threads.push_back(new LockUnlockLockDefaultIsolateThread(context));
    }
  }
  StartJoinAndDeleteThreads(threads);
}


TEST(Regress1433) {
  for (int i = 0; i < 10; i++) {
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    {
      v8::Locker lock(isolate);
      v8::Isolate::Scope isolate_scope(isolate);
      v8::HandleScope handle_scope(isolate);
      v8::Local<v8::Context> context = v8::Context::New(isolate);
      v8::Context::Scope context_scope(context);
      v8::Local<v8::String> source = v8_str("1+1");
      v8::Local<v8::Script> script =
          v8::Script::Compile(context, source).ToLocalChecked();
      v8::Local<v8::Value> result = script->Run(context).ToLocalChecked();
      v8::String::Utf8Value utf8(isolate, result);
    }
    isolate->Dispose();
  }
}


static const char* kSimpleExtensionSource =
  "(function Foo() {"
  "  return 4;"
  "})() ";

class IsolateGenesisThread : public JoinableThread {
 public:
  IsolateGenesisThread(int count, const char* extension_names[])
    : JoinableThread("IsolateGenesisThread"),
      count_(count),
      extension_names_(extension_names)
  {}

  void Run() override {
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    {
      v8::Isolate::Scope isolate_scope(isolate);
      v8::ExtensionConfiguration extensions(count_, extension_names_);
      v8::HandleScope handle_scope(isolate);
      v8::Context::New(isolate, &extensions);
    }
    isolate->Dispose();
  }

 private:
  int count_;
  const char** extension_names_;
};


// Test installing extensions in separate isolates concurrently.
// http://code.google.com/p/v8/issues/detail?id=1821
TEST(ExtensionsRegistration) {
#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
  const int kNThreads = 10;
#elif V8_TARGET_ARCH_S390 && V8_TARGET_ARCH_32_BIT
  const int kNThreads = 10;
#else
  const int kNThreads = 40;
#endif
  const char* extension_names[] = {"test0", "test1", "test2", "test3",
                                   "test4", "test5", "test6", "test7"};
  for (const char* name : extension_names) {
    v8::RegisterExtension(
        v8::base::make_unique<v8::Extension>(name, kSimpleExtensionSource));
  }
  std::vector<JoinableThread*> threads;
  threads.reserve(kNThreads);
  for (int i = 0; i < kNThreads; i++) {
    threads.push_back(new IsolateGenesisThread(8, extension_names));
  }
  StartJoinAndDeleteThreads(threads);
}

}  // namespace test_lockers
}  // namespace internal
}  // namespace v8