This implements per-isolate locking and unlocking, including tests

BUG=
TEST=

Review URL: http://codereview.chromium.org/6788023

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -3355,26 +3355,20 @@ class V8EXPORT Context {
  * to the user of V8 to ensure (perhaps with locking) that this
  * constraint is not violated.
  *
- * More then one thread and multiple V8 isolates can be used
- * without any locking if each isolate is created and accessed
- * by a single thread only. For example, one thread can use
- * multiple isolates or multiple threads can each create and run
- * their own isolate.
+ * v8::Locker is a scoped lock object. While it's
+ * active (i.e. between its construction and destruction) the current thread is
+ * allowed to use the locked isolate. V8 guarantees that an isolate can be locked
+ * by at most one thread at any time. In other words, the scope of a v8::Locker is
+ * a critical section.
  *
- * If you wish to start using V8 isolate in more then one thread
- * you can do this by constructing a v8::Locker object to guard
- * access to the isolate. After the code using V8 has completed
- * for the current thread you can call the destructor.  This can
- * be combined with C++ scope-based construction as follows
- * (assumes the default isolate that is used if not specified as
- * a parameter for the Locker):
- *
- * \code
+ * Sample usage:
+* \code
  * ...
  * {
- *   v8::Locker locker;
+ *   v8::Locker locker(isolate);
+ *   v8::Isolate::Scope isolate_scope(isolate);
  *   ...
- *   // Code using V8 goes here.
+ *   // Code using V8 and isolate goes here.
  *   ...
  * } // Destructor called here
  * \endcode
@@ -3385,11 +3379,13 @@ class V8EXPORT Context {
  *
  * \code
  * {
- *   v8::Unlocker unlocker;
+ *   isolate->Exit();
+ *   v8::Unlocker unlocker(isolate);
  *   ...
  *   // Code not using V8 goes here while V8 can run in another thread.
  *   ...
  * } // Destructor called here.
+ * isolate->Enter();
  * \endcode
  *
  * The Unlocker object is intended for use in a long-running callback
@@ -3409,32 +3405,45 @@ class V8EXPORT Context {
  * \code
  * // V8 not locked.
  * {
- *   v8::Locker locker;
+ *   v8::Locker locker(isolate);
+ *   Isolate::Scope isolate_scope(isolate);
  *   // V8 locked.
  *   {
- *     v8::Locker another_locker;
+ *     v8::Locker another_locker(isolate);
  *     // V8 still locked (2 levels).
  *     {
- *       v8::Unlocker unlocker;
+ *       isolate->Exit();
+ *       v8::Unlocker unlocker(isolate);
  *       // V8 not locked.
  *     }
+ *     isolate->Enter();
  *     // V8 locked again (2 levels).
  *   }
  *   // V8 still locked (1 level).
  * }
  * // V8 Now no longer locked.
  * \endcode
+ *
+ * 
  */
 class V8EXPORT Unlocker {
  public:
-  Unlocker();
+  /**
+   * Initialize Unlocker for a given Isolate. NULL means default isolate.
+   */
+  explicit Unlocker(Isolate* isolate = NULL);
   ~Unlocker();
+ private:
+  internal::Isolate* isolate_;
 };
 
 
 class V8EXPORT Locker {
  public:
-  Locker();
+  /**
+   * Initialize Locker for a given Isolate. NULL means default isolate.
+   */
+  explicit Locker(Isolate* isolate = NULL);
   ~Locker();
 
   /**
@@ -3452,9 +3461,10 @@ class V8EXPORT Locker {
   static void StopPreemption();
 
   /**
-   * Returns whether or not the locker is locked by the current thread.
+   * Returns whether or not the locker for a given isolate, or default isolate if NULL is given,
+   * is locked by the current thread.
    */
-  static bool IsLocked();
+  static bool IsLocked(Isolate* isolate = NULL);
 
   /**
    * Returns whether v8::Locker is being used by this V8 instance.
@@ -3464,6 +3474,7 @@ class V8EXPORT Locker {
  private:
   bool has_lock_;
   bool top_level_;
+  internal::Isolate* isolate_;
 
   static bool active_;
 

src/api.cc

@@ -53,7 +53,6 @@
 
 #define LOG_API(isolate, expr) LOG(isolate, ApiEntryCall(expr))
 
-// TODO(isolates): avoid repeated TLS reads in function prologues.
 #ifdef ENABLE_VMSTATE_TRACKING
 #define ENTER_V8(isolate)                                        \
   ASSERT((isolate)->IsInitialized());                           \
@@ -290,6 +289,7 @@ static inline bool EnsureInitializedForIsolate(i::Isolate* isolate,
   if (isolate != NULL) {
     if (isolate->IsInitialized()) return true;
   }
+  ASSERT(isolate == i::Isolate::Current());
   return ApiCheck(InitializeHelper(), location, "Error initializing V8");
 }
 
@@ -5687,9 +5687,8 @@ void HandleScopeImplementer::FreeThreadResources() {
 
 
 char* HandleScopeImplementer::ArchiveThread(char* storage) {
-  Isolate* isolate = Isolate::Current();
   v8::ImplementationUtilities::HandleScopeData* current =
-      isolate->handle_scope_data();
+      isolate_->handle_scope_data();
   handle_scope_data_ = *current;
   memcpy(storage, this, sizeof(*this));
 
@@ -5707,7 +5706,7 @@ int HandleScopeImplementer::ArchiveSpacePerThread() {
 
 char* HandleScopeImplementer::RestoreThread(char* storage) {
   memcpy(this, storage, sizeof(*this));
-  *Isolate::Current()->handle_scope_data() = handle_scope_data_;
+  *isolate_->handle_scope_data() = handle_scope_data_;
   return storage + ArchiveSpacePerThread();
 }
 
@@ -5733,7 +5732,7 @@ void HandleScopeImplementer::IterateThis(ObjectVisitor* v) {
 
 void HandleScopeImplementer::Iterate(ObjectVisitor* v) {
   v8::ImplementationUtilities::HandleScopeData* current =
-      Isolate::Current()->handle_scope_data();
+      isolate_->handle_scope_data();
   handle_scope_data_ = *current;
   IterateThis(v);
 }

src/api.h

@@ -399,8 +399,9 @@ class StringTracker {
 ISOLATED_CLASS HandleScopeImplementer {
  public:
 
-  HandleScopeImplementer()
-      : blocks_(0),
+  explicit HandleScopeImplementer(Isolate* isolate)
+      : isolate_(isolate),
+        blocks_(0),
         entered_contexts_(0),
         saved_contexts_(0),
         spare_(NULL),
@@ -466,6 +467,7 @@ ISOLATED_CLASS HandleScopeImplementer {
     ASSERT(call_depth_ == 0);
   }
 
+  Isolate* isolate_;
   List<internal::Object**> blocks_;
   // Used as a stack to keep track of entered contexts.
   List<Handle<Object> > entered_contexts_;

src/execution.cc

@@ -457,8 +457,9 @@ void StackGuard::ClearThread(const ExecutionAccess& lock) {
 
 void StackGuard::InitThread(const ExecutionAccess& lock) {
   if (thread_local_.Initialize()) isolate_->heap()->SetStackLimits();
-  uintptr_t stored_limit =
-      Isolate::CurrentPerIsolateThreadData()->stack_limit();
+  Isolate::PerIsolateThreadData* per_thread =
+      isolate_->FindOrAllocatePerThreadDataForThisThread();
+  uintptr_t stored_limit = per_thread->stack_limit();
   // You should hold the ExecutionAccess lock when you call this.
   if (stored_limit != 0) {
     StackGuard::SetStackLimit(stored_limit);

src/isolate.cc

@@ -311,6 +311,17 @@ Isolate::PerIsolateThreadData*
 }
 
 
+Isolate::PerIsolateThreadData* Isolate::FindPerThreadDataForThisThread() {
+  ThreadId thread_id = ThreadId::Current();
+  PerIsolateThreadData* per_thread = NULL;
+  {
+    ScopedLock lock(process_wide_mutex_);
+    per_thread = thread_data_table_->Lookup(this, thread_id);
+  }
+  return per_thread;
+}
+
+
 void Isolate::EnsureDefaultIsolate() {
   ScopedLock lock(process_wide_mutex_);
   if (default_isolate_ == NULL) {
@@ -322,7 +333,9 @@ void Isolate::EnsureDefaultIsolate() {
   }
   // Can't use SetIsolateThreadLocals(default_isolate_, NULL) here
   // becase a non-null thread data may be already set.
-  Thread::SetThreadLocal(isolate_key_, default_isolate_);
+  if (Thread::GetThreadLocal(isolate_key_) == NULL) {
+    Thread::SetThreadLocal(isolate_key_, default_isolate_);
+  }
   CHECK(default_isolate_->PreInit());
 }
 
@@ -458,6 +471,11 @@ Isolate::Isolate()
   zone_.isolate_ = this;
   stack_guard_.isolate_ = this;
 
+  // ThreadManager is initialized early to support locking an isolate
+  // before it is entered.
+  thread_manager_ = new ThreadManager();
+  thread_manager_->isolate_ = this;
+
 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
     defined(V8_TARGET_ARCH_MIPS) && !defined(__mips__)
   simulator_initialized_ = false;
@@ -643,7 +661,6 @@ bool Isolate::PreInit() {
   TRACE_ISOLATE(preinit);
 
   ASSERT(Isolate::Current() == this);
-
 #ifdef ENABLE_DEBUGGER_SUPPORT
   debug_ = new Debug(this);
   debugger_ = new Debugger();
@@ -671,8 +688,6 @@ bool Isolate::PreInit() {
 
   string_tracker_ = new StringTracker();
   string_tracker_->isolate_ = this;
-  thread_manager_ = new ThreadManager();
-  thread_manager_->isolate_ = this;
   compilation_cache_ = new CompilationCache(this);
   transcendental_cache_ = new TranscendentalCache();
   keyed_lookup_cache_ = new KeyedLookupCache();
@@ -683,7 +698,7 @@ bool Isolate::PreInit() {
   write_input_buffer_ = new StringInputBuffer();
   global_handles_ = new GlobalHandles(this);
   bootstrapper_ = new Bootstrapper();
-  handle_scope_implementer_ = new HandleScopeImplementer();
+  handle_scope_implementer_ = new HandleScopeImplementer(this);
   stub_cache_ = new StubCache(this);
   ast_sentinels_ = new AstSentinels();
   regexp_stack_ = new RegExpStack();
@@ -700,6 +715,7 @@ bool Isolate::PreInit() {
 
 
 void Isolate::InitializeThreadLocal() {
+  thread_local_top_.isolate_ = this;
   thread_local_top_.Initialize();
   clear_pending_exception();
   clear_pending_message();

src/isolate.h

@@ -224,6 +224,7 @@ class ThreadLocalTop BASE_EMBEDDED {
     ASSERT(try_catch_handler_address_ == NULL);
   }
 
+  Isolate* isolate_;
   // The context where the current execution method is created and for variable
   // lookups.
   Context* context_;
@@ -486,6 +487,10 @@ class Isolate {
   // Safe to call multiple times.
   static void EnsureDefaultIsolate();
 
+  // Find the PerThread for this particular (isolate, thread) combination
+  // If one does not yet exist, return null.
+  PerIsolateThreadData* FindPerThreadDataForThisThread();
+
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // Get the debugger from the default isolate. Preinitializes the
   // default isolate if needed.
@@ -1065,7 +1070,7 @@ class Isolate {
   // If one does not yet exist, allocate a new one.
   PerIsolateThreadData* FindOrAllocatePerThreadDataForThisThread();
 
-  // PreInits and returns a default isolate. Needed when a new thread tries
+// PreInits and returns a default isolate. Needed when a new thread tries
   // to create a Locker for the first time (the lock itself is in the isolate).
   static Isolate* GetDefaultIsolateForLocking();
 
@@ -1197,9 +1202,12 @@ class Isolate {
 
   friend class ExecutionAccess;
   friend class IsolateInitializer;
+  friend class ThreadManager;
+  friend class StackGuard;
   friend class ThreadId;
   friend class v8::Isolate;
   friend class v8::Locker;
+  friend class v8::Unlocker;
 
   DISALLOW_COPY_AND_ASSIGN(Isolate);
 };

src/objects.cc

@@ -4958,8 +4958,7 @@ int Relocatable::ArchiveSpacePerThread() {
 
 
 // Archive statics that are thread local.
-char* Relocatable::ArchiveState(char* to) {
-  Isolate* isolate = Isolate::Current();
+char* Relocatable::ArchiveState(Isolate* isolate, char* to) {
   *reinterpret_cast<Relocatable**>(to) = isolate->relocatable_top();
   isolate->set_relocatable_top(NULL);
   return to + ArchiveSpacePerThread();
@@ -4967,8 +4966,7 @@ char* Relocatable::ArchiveState(char* to) {
 
 
 // Restore statics that are thread local.
-char* Relocatable::RestoreState(char* from) {
-  Isolate* isolate = Isolate::Current();
+char* Relocatable::RestoreState(Isolate* isolate, char* from) {
   isolate->set_relocatable_top(*reinterpret_cast<Relocatable**>(from));
   return from + ArchiveSpacePerThread();
 }

src/objects.h

@@ -5924,8 +5924,8 @@ class Relocatable BASE_EMBEDDED {
 
   static void PostGarbageCollectionProcessing();
   static int ArchiveSpacePerThread();
-  static char* ArchiveState(char* to);
-  static char* RestoreState(char* from);
+  static char* ArchiveState(Isolate* isolate, char* to);
+  static char* RestoreState(Isolate* isolate, char* from);
   static void Iterate(ObjectVisitor* v);
   static void Iterate(ObjectVisitor* v, Relocatable* top);
   static char* Iterate(ObjectVisitor* v, char* t);

src/top.cc

@@ -77,9 +77,9 @@ void ThreadLocalTop::Initialize() {
   InitializeInternal();
 #ifdef USE_SIMULATOR
 #ifdef V8_TARGET_ARCH_ARM
-  simulator_ = Simulator::current(Isolate::Current());
+  simulator_ = Simulator::current(isolate_);
 #elif V8_TARGET_ARCH_MIPS
-  simulator_ = Simulator::current(Isolate::Current());
+  simulator_ = Simulator::current(isolate_);
 #endif
 #endif
   thread_id_ = ThreadId::Current();

src/v8threads.cc

@@ -43,90 +43,85 @@ bool Locker::active_ = false;
 
 
 // Constructor for the Locker object.  Once the Locker is constructed the
-// current thread will be guaranteed to have the big V8 lock.
-Locker::Locker() : has_lock_(false), top_level_(true) {
-  // TODO(isolates): When Locker has Isolate parameter and it is provided, grab
-  // that one instead of using the current one.
-  // We pull default isolate for Locker constructor w/o p[arameter.
-  // A thread should not enter an isolate before acquiring a lock,
-  // in cases which mandate using Lockers.
-  // So getting a lock is the first thing threads do in a scenario where
-  // multple threads share an isolate. Hence, we need to access
-  // 'locking isolate' before we can actually enter into default isolate.
-  internal::Isolate* isolate = internal::Isolate::GetDefaultIsolateForLocking();
-  ASSERT(isolate != NULL);
-
+// current thread will be guaranteed to have the lock for a given isolate.
+Locker::Locker(v8::Isolate* isolate)
+  : has_lock_(false),
+    top_level_(false),
+    isolate_(reinterpret_cast<i::Isolate*>(isolate)) {
+  if (isolate_ == NULL) {
+    isolate_ = i::Isolate::GetDefaultIsolateForLocking();
+  }
   // Record that the Locker has been used at least once.
   active_ = true;
   // Get the big lock if necessary.
-  if (!isolate->thread_manager()->IsLockedByCurrentThread()) {
-    isolate->thread_manager()->Lock();
+  if (!isolate_->thread_manager()->IsLockedByCurrentThread()) {
+    isolate_->thread_manager()->Lock();
     has_lock_ = true;
 
-    if (isolate->IsDefaultIsolate()) {
-      // This only enters if not yet entered.
-      internal::Isolate::EnterDefaultIsolate();
-    }
-
-    ASSERT(internal::Thread::HasThreadLocal(
-        internal::Isolate::thread_id_key()));
-
     // Make sure that V8 is initialized.  Archiving of threads interferes
     // with deserialization by adding additional root pointers, so we must
     // initialize here, before anyone can call ~Locker() or Unlocker().
-    if (!isolate->IsInitialized()) {
+    if (isolate_->IsDefaultIsolate()) {
+      // This only enters if not yet entered.
+      internal::Isolate::EnterDefaultIsolate();
+    } else if (!isolate_->IsInitialized()) {
+      isolate_->Enter();
       V8::Initialize();
+      isolate_->Exit();
     }
+
     // This may be a locker within an unlocker in which case we have to
     // get the saved state for this thread and restore it.
-    if (isolate->thread_manager()->RestoreThread()) {
+    if (isolate_->thread_manager()->RestoreThread()) {
       top_level_ = false;
     } else {
-      internal::ExecutionAccess access(isolate);
-      isolate->stack_guard()->ClearThread(access);
-      isolate->stack_guard()->InitThread(access);
+      internal::ExecutionAccess access(isolate_);
+      isolate_->stack_guard()->ClearThread(access);
+      isolate_->stack_guard()->InitThread(access);
     }
   }
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
 }
 
 
-bool Locker::IsLocked() {
-  return internal::Isolate::Current()->thread_manager()->
-      IsLockedByCurrentThread();
+bool Locker::IsLocked(v8::Isolate* isolate) {
+  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  if (internal_isolate == NULL) {
+    internal_isolate = i::Isolate::GetDefaultIsolateForLocking();
+  }
+  return internal_isolate->thread_manager()->IsLockedByCurrentThread();
 }
 
 
 Locker::~Locker() {
-  // TODO(isolate): this should use a field storing the isolate it
-  // locked instead.
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
   if (has_lock_) {
     if (top_level_) {
-      isolate->thread_manager()->FreeThreadResources();
+      isolate_->thread_manager()->FreeThreadResources();
     } else {
-      isolate->thread_manager()->ArchiveThread();
+      isolate_->thread_manager()->ArchiveThread();
     }
-    isolate->thread_manager()->Unlock();
+    isolate_->thread_manager()->Unlock();
   }
 }
 
 
-Unlocker::Unlocker() {
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
-  isolate->thread_manager()->ArchiveThread();
-  isolate->thread_manager()->Unlock();
+Unlocker::Unlocker(v8::Isolate* isolate)
+  : isolate_(reinterpret_cast<i::Isolate*>(isolate)) {
+  if (isolate_ == NULL) {
+    isolate_ = i::Isolate::GetDefaultIsolateForLocking();
+  }
+
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
+  isolate_->thread_manager()->ArchiveThread();
+  isolate_->thread_manager()->Unlock();
 }
 
 
 Unlocker::~Unlocker() {
-  // TODO(isolates): check it's the isolate we unlocked.
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(!isolate->thread_manager()->IsLockedByCurrentThread());
-  isolate->thread_manager()->Lock();
-  isolate->thread_manager()->RestoreThread();
+  ASSERT(!isolate_->thread_manager()->IsLockedByCurrentThread());
+  isolate_->thread_manager()->Lock();
+  isolate_->thread_manager()->RestoreThread();
 }
 
 
@@ -144,17 +139,20 @@ namespace internal {
 
 
 bool ThreadManager::RestoreThread() {
+  ASSERT(IsLockedByCurrentThread());
   // First check whether the current thread has been 'lazily archived', ie
   // not archived at all.  If that is the case we put the state storage we
   // had prepared back in the free list, since we didn't need it after all.
   if (lazily_archived_thread_.Equals(ThreadId::Current())) {
     lazily_archived_thread_ = ThreadId::Invalid();
-    ASSERT(Isolate::CurrentPerIsolateThreadData()->thread_state() ==
-           lazily_archived_thread_state_);
+    Isolate::PerIsolateThreadData* per_thread =
+        isolate_->FindPerThreadDataForThisThread();
+    ASSERT(per_thread != NULL);
+    ASSERT(per_thread->thread_state() == lazily_archived_thread_state_);
     lazily_archived_thread_state_->set_id(ThreadId::Invalid());
     lazily_archived_thread_state_->LinkInto(ThreadState::FREE_LIST);
     lazily_archived_thread_state_ = NULL;
-    Isolate::CurrentPerIsolateThreadData()->set_thread_state(NULL);
+    per_thread->set_thread_state(NULL);
     return true;
   }
 
@@ -168,7 +166,7 @@ bool ThreadManager::RestoreThread() {
     EagerlyArchiveThread();
   }
   Isolate::PerIsolateThreadData* per_thread =
-      Isolate::CurrentPerIsolateThreadData();
+      isolate_->FindPerThreadDataForThisThread();
   if (per_thread == NULL || per_thread->thread_state() == NULL) {
     // This is a new thread.
     isolate_->stack_guard()->InitThread(access);
@@ -178,7 +176,7 @@ bool ThreadManager::RestoreThread() {
   char* from = state->data();
   from = isolate_->handle_scope_implementer()->RestoreThread(from);
   from = isolate_->RestoreThread(from);
-  from = Relocatable::RestoreState(from);
+  from = Relocatable::RestoreState(isolate_, from);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   from = isolate_->debug()->RestoreDebug(from);
 #endif
@@ -300,9 +298,12 @@ ThreadManager::~ThreadManager() {
 void ThreadManager::ArchiveThread() {
   ASSERT(lazily_archived_thread_.Equals(ThreadId::Invalid()));
   ASSERT(!IsArchived());
+  ASSERT(IsLockedByCurrentThread());
   ThreadState* state = GetFreeThreadState();
   state->Unlink();
-  Isolate::CurrentPerIsolateThreadData()->set_thread_state(state);
+  Isolate::PerIsolateThreadData* per_thread =
+      isolate_->FindOrAllocatePerThreadDataForThisThread();
+  per_thread->set_thread_state(state);
   lazily_archived_thread_ = ThreadId::Current();
   lazily_archived_thread_state_ = state;
   ASSERT(state->id().Equals(ThreadId::Invalid()));
@@ -312,6 +313,7 @@ void ThreadManager::ArchiveThread() {
 
 
 void ThreadManager::EagerlyArchiveThread() {
+  ASSERT(IsLockedByCurrentThread());
   ThreadState* state = lazily_archived_thread_state_;
   state->LinkInto(ThreadState::IN_USE_LIST);
   char* to = state->data();
@@ -319,7 +321,7 @@ void ThreadManager::EagerlyArchiveThread() {
   // in ThreadManager::Iterate(ObjectVisitor*).
   to = isolate_->handle_scope_implementer()->ArchiveThread(to);
   to = isolate_->ArchiveThread(to);
-  to = Relocatable::ArchiveState(to);
+  to = Relocatable::ArchiveState(isolate_, to);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   to = isolate_->debug()->ArchiveDebug(to);
 #endif
@@ -344,11 +346,11 @@ void ThreadManager::FreeThreadResources() {
 
 
 bool ThreadManager::IsArchived() {
-  Isolate::PerIsolateThreadData* data = Isolate::CurrentPerIsolateThreadData();
+  Isolate::PerIsolateThreadData* data =
+      isolate_->FindPerThreadDataForThisThread();
   return data != NULL && data->thread_state() != NULL;
 }
 
-
 void ThreadManager::Iterate(ObjectVisitor* v) {
   // Expecting no threads during serialization/deserialization
   for (ThreadState* state = FirstThreadStateInUse();

test/cctest/SConscript

@@ -64,6 +64,7 @@ SOURCES = {
     'test-list.cc',
     'test-liveedit.cc',
     'test-lock.cc',
+    'test-lockers.cc',
     'test-log-utils.cc',
     'test-log.cc',
     'test-mark-compact.cc',

test/cctest/cctest.gyp

@@ -93,6 +93,7 @@
         'test-list.cc',
         'test-liveedit.cc',
         'test-lock.cc',
+        'test-lockers.cc',
         'test-log.cc',
         'test-log-utils.cc',
         'test-mark-compact.cc',

test/cctest/test-api.cc

@@ -30,6 +30,7 @@
 #include "v8.h"
 
 #include "api.h"
+#include "isolate.h"
 #include "compilation-cache.h"
 #include "execution.h"
 #include "snapshot.h"
@@ -13386,6 +13387,28 @@ TEST(MultipleIsolatesOnIndividualThreads) {
   isolate2->Dispose();
 }
 
+TEST(IsolateDifferentContexts) {
+  v8::Isolate* isolate = v8::Isolate::New();
+  Persistent<v8::Context> context;
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope;
+    context = v8::Context::New();
+    v8::Context::Scope context_scope(context);
+    Local<Value> v = CompileRun("2");
+    CHECK(v->IsNumber());
+    CHECK_EQ(2, static_cast<int>(v->NumberValue()));
+  }
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope;
+    context = v8::Context::New();
+    v8::Context::Scope context_scope(context);
+    Local<Value> v = CompileRun("22");
+    CHECK(v->IsNumber());
+    CHECK_EQ(22, static_cast<int>(v->NumberValue()));
+  }
+}
 
 class InitDefaultIsolateThread : public v8::internal::Thread {
  public: