Changed structure of accessor arguments passing to allow accessor

callbacks to be called directly from native code.

Review URL: http://codereview.chromium.org/242050


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2995 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -130,6 +130,7 @@ class Data;
 namespace internal {
 
 class Object;
+class Arguments;
 
 }
 
@@ -1408,17 +1409,13 @@ class V8EXPORT Arguments {
  */
 class V8EXPORT AccessorInfo {
  public:
-  inline AccessorInfo(Local<Object> self,
-                      Local<Value> data,
-                      Local<Object> holder)
-      : self_(self), data_(data), holder_(holder) { }
+  inline AccessorInfo(internal::Object** args)
+      : args_(args) { }
   inline Local<Value> Data() const;
   inline Local<Object> This() const;
   inline Local<Object> Holder() const;
  private:
-  Local<Object> self_;
-  Local<Value> data_;
-  Local<Object> holder_;
+  internal::Object** args_;
 };
 
 
@@ -2873,21 +2870,6 @@ int Arguments::Length() const {
 }
 
 
-Local<Value> AccessorInfo::Data() const {
-  return data_;
-}
-
-
-Local<Object> AccessorInfo::This() const {
-  return self_;
-}
-
-
-Local<Object> AccessorInfo::Holder() const {
-  return holder_;
-}
-
-
 template <class T>
 Local<T> HandleScope::Close(Handle<T> value) {
   internal::Object** before = reinterpret_cast<internal::Object**>(*value);
@@ -3085,6 +3067,21 @@ External* External::Cast(v8::Value* value) {
 }
 
 
+Local<Value> AccessorInfo::Data() const {
+  return Local<Value>(reinterpret_cast<Value*>(&args_[-3]));
+}
+
+
+Local<Object> AccessorInfo::This() const {
+  return Local<Object>(reinterpret_cast<Object*>(&args_[0]));
+}
+
+
+Local<Object> AccessorInfo::Holder() const {
+  return Local<Object>(reinterpret_cast<Object*>(&args_[-1]));
+}
+
+
 /**
  * \example shell.cc
  * A simple shell that takes a list of expressions on the

src/api.cc

@@ -28,6 +28,7 @@
 #include "v8.h"
 
 #include "api.h"
+#include "arguments.h"
 #include "bootstrapper.h"
 #include "compiler.h"
 #include "debug.h"

src/arguments.h

@@ -45,6 +45,9 @@ namespace internal {
 
 class Arguments BASE_EMBEDDED {
  public:
+  Arguments(int length, Object** arguments)
+      : length_(length), arguments_(arguments) { }
+
   Object*& operator[] (int index) {
     ASSERT(0 <= index && index < length_);
     return arguments_[-index];
@@ -61,11 +64,34 @@ class Arguments BASE_EMBEDDED {
   // Get the total number of arguments including the receiver.
   int length() const { return length_; }
   
+  Object** arguments() { return arguments_; }
+
  private:
   int length_;
   Object** arguments_;
 };
 
+
+// Cursom arguments replicate a small segment of stack that can be
+// accessed through an Arguments object the same way the actual stack
+// can.
+class CustomArguments : public Relocatable {
+public:
+  inline CustomArguments(Object *data,
+                         JSObject *self,
+                         JSObject *holder) {
+    values_[3] = self;
+    values_[2] = holder;
+    values_[1] = Smi::FromInt(0);
+    values_[0] = data;
+  }
+  void IterateInstance(ObjectVisitor* v);
+  Object** end() { return values_ + 3; }
+private:
+  Object* values_[4];
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_ARGUMENTS_H_

src/handles.cc

@@ -29,6 +29,7 @@
 
 #include "accessors.h"
 #include "api.h"
+#include "arguments.h"
 #include "bootstrapper.h"
 #include "compiler.h"
 #include "debug.h"
@@ -479,15 +480,17 @@ int GetScriptLineNumber(Handle<Script> script, int code_pos) {
 }
 
 
+void CustomArguments::IterateInstance(ObjectVisitor* v) {
+  v->VisitPointers(values_, values_ + 4);
+}
+
+
 // Compute the property keys from the interceptor.
 v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
                                                  Handle<JSObject> object) {
   Handle<InterceptorInfo> interceptor(object->GetNamedInterceptor());
-  Handle<Object> data(interceptor->data());
-  v8::AccessorInfo info(
-    v8::Utils::ToLocal(receiver),
-    v8::Utils::ToLocal(data),
-    v8::Utils::ToLocal(object));
+  CustomArguments args(interceptor->data(), *receiver, *object);
+  v8::AccessorInfo info(args.end());
   v8::Handle<v8::Array> result;
   if (!interceptor->enumerator()->IsUndefined()) {
     v8::NamedPropertyEnumerator enum_fun =
@@ -507,11 +510,8 @@ v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
 v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver,
                                                    Handle<JSObject> object) {
   Handle<InterceptorInfo> interceptor(object->GetIndexedInterceptor());
-  Handle<Object> data(interceptor->data());
-  v8::AccessorInfo info(
-    v8::Utils::ToLocal(receiver),
-    v8::Utils::ToLocal(data),
-    v8::Utils::ToLocal(object));
+  CustomArguments args(interceptor->data(), *receiver, *object);
+  v8::AccessorInfo info(args.end());
   v8::Handle<v8::Array> result;
   if (!interceptor->enumerator()->IsUndefined()) {
     v8::IndexedPropertyEnumerator enum_fun =

src/heap.cc

@@ -497,8 +497,8 @@ void Heap::PostGarbageCollectionProcessing() {
     DisableAssertNoAllocation allow_allocation;
     GlobalHandles::PostGarbageCollectionProcessing();
   }
-  // Update flat string readers.
-  FlatStringReader::PostGarbageCollectionProcessing();
+  // Update relocatables.
+  Relocatable::PostGarbageCollectionProcessing();
 }
 
 
@@ -3088,6 +3088,8 @@ void Heap::IterateStrongRoots(ObjectVisitor* v) {
   SYNCHRONIZE_TAG("bootstrapper");
   Top::Iterate(v);
   SYNCHRONIZE_TAG("top");
+  Relocatable::Iterate(v);
+  SYNCHRONIZE_TAG("relocatable");
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   Debug::Iterate(v);

src/objects.h

@@ -4219,25 +4219,44 @@ class ExternalTwoByteString: public ExternalString {
 };
 
 
+// Utility superclass for stack-allocated objects that must be updated
+// on gc.  It provides two ways for the gc to update instances, either
+// iterating or updating after gc.
+class Relocatable BASE_EMBEDDED {
+public:
+  inline Relocatable() : prev_(top_) { top_ = this; }
+  virtual ~Relocatable() { ASSERT_EQ(top_, this); top_ = prev_; }
+  virtual void IterateInstance(ObjectVisitor* v) { }
+  virtual void PostGarbageCollection() { }
+
+  static void PostGarbageCollectionProcessing();
+  static int ArchiveSpacePerThread();
+  static char* ArchiveState(char* to);
+  static char* RestoreState(char* from);
+  static void Iterate(ObjectVisitor* v);
+  static void Iterate(ObjectVisitor* v, Relocatable* top);
+  static char* Iterate(ObjectVisitor* v, char* t);
+private:
+  static Relocatable* top_;
+  Relocatable* prev_;
+};
+
+
 // A flat string reader provides random access to the contents of a
 // string independent of the character width of the string.  The handle
 // must be valid as long as the reader is being used.
-class FlatStringReader BASE_EMBEDDED {
+class FlatStringReader : public Relocatable {
  public:
   explicit FlatStringReader(Handle<String> str);
   explicit FlatStringReader(Vector<const char> input);
-  ~FlatStringReader();
-  void RefreshState();
+  void PostGarbageCollection();
   inline uc32 Get(int index);
   int length() { return length_; }
-  static void PostGarbageCollectionProcessing();
  private:
   String** str_;
   bool is_ascii_;
   int length_;
   const void* start_;
-  FlatStringReader* prev_;
-  static FlatStringReader* top_;
 };
 
 

src/stub-cache.cc

@@ -735,28 +735,17 @@ Handle<Code> ComputeCallMiss(int argc) {
 
 
 Object* LoadCallbackProperty(Arguments args) {
-  Handle<JSObject> recv = args.at<JSObject>(0);
-  Handle<JSObject> holder = args.at<JSObject>(1);
   AccessorInfo* callback = AccessorInfo::cast(args[2]);
-  Handle<Object> data = args.at<Object>(3);
   Address getter_address = v8::ToCData<Address>(callback->getter());
   v8::AccessorGetter fun = FUNCTION_CAST<v8::AccessorGetter>(getter_address);
   ASSERT(fun != NULL);
-  Handle<String> name = args.at<String>(4);
-  // NOTE: If we can align the structure of an AccessorInfo with the
-  // locations of the arguments to this function maybe we don't have
-  // to explicitly create the structure but can just pass a pointer
-  // into the stack.
-  LOG(ApiNamedPropertyAccess("load", *recv, *name));
-  v8::AccessorInfo info(v8::Utils::ToLocal(recv),
-                        v8::Utils::ToLocal(data),
-                        v8::Utils::ToLocal(holder));
+  v8::AccessorInfo info(args.arguments());
   HandleScope scope;
   v8::Handle<v8::Value> result;
   {
     // Leaving JavaScript.
     VMState state(EXTERNAL);
-    result = fun(v8::Utils::ToLocal(name), info);
+    result = fun(v8::Utils::ToLocal(args.at<String>(4)), info);
   }
   RETURN_IF_SCHEDULED_EXCEPTION();
   if (result.IsEmpty()) return Heap::undefined_value();
@@ -765,7 +754,7 @@ Object* LoadCallbackProperty(Arguments args) {
 
 
 Object* StoreCallbackProperty(Arguments args) {
-  Handle<JSObject> recv = args.at<JSObject>(0);
+  JSObject* recv = JSObject::cast(args[0]);
   AccessorInfo* callback = AccessorInfo::cast(args[1]);
   Address setter_address = v8::ToCData<Address>(callback->setter());
   v8::AccessorSetter fun = FUNCTION_CAST<v8::AccessorSetter>(setter_address);
@@ -773,11 +762,9 @@ Object* StoreCallbackProperty(Arguments args) {
   Handle<String> name = args.at<String>(2);
   Handle<Object> value = args.at<Object>(3);
   HandleScope scope;
-  Handle<Object> data(callback->data());
-  LOG(ApiNamedPropertyAccess("store", *recv, *name));
-  v8::AccessorInfo info(v8::Utils::ToLocal(recv),
-                        v8::Utils::ToLocal(data),
-                        v8::Utils::ToLocal(recv));
+  LOG(ApiNamedPropertyAccess("store", recv, *name));
+  CustomArguments custom_args(callback->data(), recv, recv);
+  v8::AccessorInfo info(custom_args.end());
   {
     // Leaving JavaScript.
     VMState state(EXTERNAL);
@@ -795,11 +782,11 @@ Object* StoreCallbackProperty(Arguments args) {
  * provide any value for the given name.
  */
 Object* LoadPropertyWithInterceptorOnly(Arguments args) {
-  Handle<JSObject> receiver_handle = args.at<JSObject>(0);
-  Handle<JSObject> holder_handle = args.at<JSObject>(1);
+  JSObject* receiver_handle = JSObject::cast(args[0]);
+  JSObject* holder_handle = JSObject::cast(args[1]);
   Handle<String> name_handle = args.at<String>(2);
   Handle<InterceptorInfo> interceptor_info = args.at<InterceptorInfo>(3);
-  Handle<Object> data_handle = args.at<Object>(4);
+  Object* data_handle = args[4];
 
   Address getter_address = v8::ToCData<Address>(interceptor_info->getter());
   v8::NamedPropertyGetter getter =
@@ -808,9 +795,8 @@ Object* LoadPropertyWithInterceptorOnly(Arguments args) {
 
   {
     // Use the interceptor getter.
-    v8::AccessorInfo info(v8::Utils::ToLocal(receiver_handle),
-                          v8::Utils::ToLocal(data_handle),
-                          v8::Utils::ToLocal(holder_handle));
+    CustomArguments args(data_handle, receiver_handle, holder_handle);
+    v8::AccessorInfo info(args.end());
     HandleScope scope;
     v8::Handle<v8::Value> r;
     {
@@ -861,9 +847,8 @@ static Object* LoadWithInterceptor(Arguments* args,
 
   {
     // Use the interceptor getter.
-    v8::AccessorInfo info(v8::Utils::ToLocal(receiver_handle),
-                          v8::Utils::ToLocal(data_handle),
-                          v8::Utils::ToLocal(holder_handle));
+    CustomArguments args(*data_handle, *receiver_handle, *holder_handle);
+    v8::AccessorInfo info(args.end());
     HandleScope scope;
     v8::Handle<v8::Value> r;
     {

src/v8threads.cc

@@ -146,6 +146,7 @@ bool ThreadManager::RestoreThread() {
   char* from = state->data();
   from = HandleScopeImplementer::RestoreThread(from);
   from = Top::RestoreThread(from);
+  from = Relocatable::RestoreState(from);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   from = Debug::RestoreDebug(from);
 #endif
@@ -185,7 +186,8 @@ static int ArchiveSpacePerThread() {
 #endif
                      StackGuard::ArchiveSpacePerThread() +
                     RegExpStack::ArchiveSpacePerThread() +
-                   Bootstrapper::ArchiveSpacePerThread();
+                   Bootstrapper::ArchiveSpacePerThread() +
+                    Relocatable::ArchiveSpacePerThread();
 }
 
 
@@ -275,6 +277,7 @@ void ThreadManager::EagerlyArchiveThread() {
   // in ThreadManager::Iterate(ObjectVisitor*).
   to = HandleScopeImplementer::ArchiveThread(to);
   to = Top::ArchiveThread(to);
+  to = Relocatable::ArchiveState(to);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   to = Debug::ArchiveDebug(to);
 #endif
@@ -311,6 +314,7 @@ void ThreadManager::Iterate(ObjectVisitor* v) {
     char* data = state->data();
     data = HandleScopeImplementer::Iterate(v, data);
     data = Top::Iterate(v, data);
+    data = Relocatable::Iterate(v, data);
   }
 }