Reland r17907 - Make it possible to add more than one piece of embedder data to isolates"

This will allow for using gin and blink bindings in the same
process.

Over r17907, I changed the order of fields in Isolate to be stable across different platforms, since the ABI defined packing is not the same on
all targets, and I initialize the embedder data field in Isolate.

BUG=317398
R=svenpanne@chromium.org, dcarney@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/78453002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17935 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -4054,16 +4054,36 @@ class V8_EXPORT Isolate {
   void Dispose();
 
   /**
-   * Associate embedder-specific data with the isolate
+   * Associate embedder-specific data with the isolate. This legacy method
+   * puts the data in the 0th slot. It will be deprecated soon.
    */
   V8_INLINE void SetData(void* data);
 
   /**
-   * Retrieve embedder-specific data from the isolate.
+   * Associate embedder-specific data with the isolate. |slot| has to be
+   * between 0 and GetNumberOfDataSlots() - 1.
+   */
+  V8_INLINE void SetData(uint32_t slot, void* data);
+
+  /**
+   * Retrieve embedder-specific data from the isolate. This legacy method
+   * retrieves the data from slot 0. It will be deprecated soon.
    * Returns NULL if SetData has never been called.
    */
   V8_INLINE void* GetData();
 
+  /**
+   * Retrieve embedder-specific data from the isolate.
+   * Returns NULL if SetData has never been called for the given |slot|.
+   */
+  V8_INLINE void* GetData(uint32_t slot);
+
+  /**
+   * Returns the maximum number of available embedder data slots. Valid slots
+   * are in the range of 0 - GetNumberOfDataSlots() - 1.
+   */
+  V8_INLINE static uint32_t GetNumberOfDataSlots();
+
   /**
    * Get statistics about the heap memory usage.
    */
@@ -5448,8 +5468,8 @@ class Internals {
   static const int kExternalTwoByteRepresentationTag = 0x02;
   static const int kExternalAsciiRepresentationTag = 0x06;
 
-  static const int kIsolateEmbedderDataOffset = 1 * kApiPointerSize;
-  static const int kIsolateRootsOffset = 3 * kApiPointerSize;
+  static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
+  static const int kIsolateRootsOffset = 5 * kApiPointerSize;
   static const int kUndefinedValueRootIndex = 5;
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
@@ -5473,6 +5493,8 @@ class Internals {
   static const int kUndefinedOddballKind = 5;
   static const int kNullOddballKind = 3;
 
+  static const uint32_t kNumIsolateDataSlots = 4;
+
   V8_EXPORT static void CheckInitializedImpl(v8::Isolate* isolate);
   V8_INLINE static void CheckInitialized(v8::Isolate* isolate) {
 #ifdef V8_ENABLE_CHECKS
@@ -5536,15 +5558,17 @@ class Internals {
     *addr = static_cast<uint8_t>((*addr & ~kNodeStateMask) | value);
   }
 
-  V8_INLINE static void SetEmbedderData(v8::Isolate* isolate, void* data) {
-    uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) +
-        kIsolateEmbedderDataOffset;
+  V8_INLINE static void SetEmbedderData(v8::Isolate *isolate,
+                                        uint32_t slot,
+                                        void *data) {
+    uint8_t *addr = reinterpret_cast<uint8_t *>(isolate) +
+                    kIsolateEmbedderDataOffset + slot * kApiPointerSize;
     *reinterpret_cast<void**>(addr) = data;
   }
 
-  V8_INLINE static void* GetEmbedderData(v8::Isolate* isolate) {
+  V8_INLINE static void* GetEmbedderData(v8::Isolate* isolate, uint32_t slot) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) +
-        kIsolateEmbedderDataOffset;
+        kIsolateEmbedderDataOffset + slot * kApiPointerSize;
     return *reinterpret_cast<void**>(addr);
   }
 
@@ -6470,13 +6494,31 @@ Handle<Boolean> False(Isolate* isolate) {
 
 void Isolate::SetData(void* data) {
   typedef internal::Internals I;
-  I::SetEmbedderData(this, data);
+  I::SetEmbedderData(this, 0, data);
 }
 
 
 void* Isolate::GetData() {
   typedef internal::Internals I;
-  return I::GetEmbedderData(this);
+  return I::GetEmbedderData(this, 0);
+}
+
+
+void Isolate::SetData(uint32_t slot, void* data) {
+  typedef internal::Internals I;
+  I::SetEmbedderData(this, slot, data);
+}
+
+
+void* Isolate::GetData(uint32_t slot) {
+  typedef internal::Internals I;
+  return I::GetEmbedderData(this, slot);
+}
+
+
+uint32_t Isolate::GetNumberOfDataSlots() {
+  typedef internal::Internals I;
+  return I::kNumIsolateDataSlots;
 }
 
 

src/d8.cc

@@ -90,15 +90,15 @@ class PerIsolateData {
  public:
   explicit PerIsolateData(Isolate* isolate) : isolate_(isolate), realms_(NULL) {
     HandleScope scope(isolate);
-    isolate->SetData(this);
+    isolate->SetData(0, this);
   }
 
   ~PerIsolateData() {
-    isolate_->SetData(NULL);  // Not really needed, just to be sure...
+    isolate_->SetData(0, NULL);  // Not really needed, just to be sure...
   }
 
   inline static PerIsolateData* Get(Isolate* isolate) {
-    return reinterpret_cast<PerIsolateData*>(isolate->GetData());
+    return reinterpret_cast<PerIsolateData*>(isolate->GetData(0));
   }
 
   class RealmScope {

src/isolate.cc

@@ -1524,8 +1524,8 @@ void Isolate::ThreadDataTable::RemoveAllThreads(Isolate* isolate) {
 
 
 Isolate::Isolate()
-    : state_(UNINITIALIZED),
-      embedder_data_(NULL),
+    : embedder_data_(),
+      state_(UNINITIALIZED),
       entry_stack_(NULL),
       stack_trace_nesting_level_(0),
       incomplete_message_(NULL),

src/isolate.h

@@ -1045,8 +1045,14 @@ class Isolate {
     thread_local_top_.current_vm_state_ = state;
   }
 
-  void SetData(void* data) { embedder_data_ = data; }
-  void* GetData() { return embedder_data_; }
+  void SetData(uint32_t slot, void* data) {
+    ASSERT(slot < Internals::kNumIsolateDataSlots);
+    embedder_data_[slot] = data;
+  }
+  void* GetData(uint32_t slot) {
+    ASSERT(slot < Internals::kNumIsolateDataSlots);
+    return embedder_data_[slot];
+  }
 
   LookupResult* top_lookup_result() {
     return thread_local_top_.top_lookup_result_;
@@ -1159,9 +1165,9 @@ class Isolate {
   // These fields are accessed through the API, offsets must be kept in sync
   // with v8::internal::Internals (in include/v8.h) constants. This is also
   // verified in Isolate::Init() using runtime checks.
-  State state_;  // Will be padded to kApiPointerSize.
-  void* embedder_data_;
+  void* embedder_data_[Internals::kNumIsolateDataSlots];
   Heap heap_;
+  State state_;  // Will be padded to kApiPointerSize.
 
   // The per-process lock should be acquired before the ThreadDataTable is
   // modified.

test/cctest/test-api.cc

@@ -19937,16 +19937,28 @@ UNINITIALIZED_TEST(IsolateEmbedderData) {
   v8::Isolate* isolate = v8::Isolate::New();
   isolate->Enter();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  CHECK_EQ(NULL, isolate->GetData());
-  CHECK_EQ(NULL, i_isolate->GetData());
-  static void* data1 = reinterpret_cast<void*>(0xacce55ed);
-  isolate->SetData(data1);
-  CHECK_EQ(data1, isolate->GetData());
-  CHECK_EQ(data1, i_isolate->GetData());
-  static void* data2 = reinterpret_cast<void*>(0xdecea5ed);
-  i_isolate->SetData(data2);
-  CHECK_EQ(data2, isolate->GetData());
-  CHECK_EQ(data2, i_isolate->GetData());
+  for (uint32_t slot = 0; slot < v8::Isolate::GetNumberOfDataSlots(); ++slot) {
+    CHECK_EQ(NULL, isolate->GetData(slot));
+    CHECK_EQ(NULL, i_isolate->GetData(slot));
+  }
+  for (uint32_t slot = 0; slot < v8::Isolate::GetNumberOfDataSlots(); ++slot) {
+    void* data = reinterpret_cast<void*>(0xacce55ed + slot);
+    isolate->SetData(slot, data);
+  }
+  for (uint32_t slot = 0; slot < v8::Isolate::GetNumberOfDataSlots(); ++slot) {
+    void* data = reinterpret_cast<void*>(0xacce55ed + slot);
+    CHECK_EQ(data, isolate->GetData(slot));
+    CHECK_EQ(data, i_isolate->GetData(slot));
+  }
+  for (uint32_t slot = 0; slot < v8::Isolate::GetNumberOfDataSlots(); ++slot) {
+    void* data = reinterpret_cast<void*>(0xdecea5ed + slot);
+    isolate->SetData(slot, data);
+  }
+  for (uint32_t slot = 0; slot < v8::Isolate::GetNumberOfDataSlots(); ++slot) {
+    void* data = reinterpret_cast<void*>(0xdecea5ed + slot);
+    CHECK_EQ(data, isolate->GetData(slot));
+    CHECK_EQ(data, i_isolate->GetData(slot));
+  }
   isolate->Exit();
   isolate->Dispose();
 }