[V8] REGRESSION(94783): calling the binding script during V8 context …

…creation slows down page loads

https://bugs.webkit.org/show_bug.cgi?id=68237

Patch by Ulan Degenbaev <ulan@chromium.org> on 2011-09-16
Reviewed by Kenneth Russell.

Call the binding script lazily on the first run of the set() method of
a typed array.

* ../../Source/WebCore/WebCore.gypi:
* ../../Source/WebCore/bindings/v8/V8BindingScripts.cpp: Removed.
* ../../Source/WebCore/bindings/v8/V8BindingScripts.h: Removed.
* ../../Source/WebCore/bindings/v8/V8DOMWindowShell.cpp:
* ../../Source/WebCore/bindings/v8/WorkerContextExecutionProxy.cpp:
* ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.cpp:
* ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.h:
* ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustomScript.js:

Canonical link: https://commits.webkit.org/84223@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@95354 268f45cc-cd09-0410-ab3c-d52691b4dbfc

ChangeLog

@@ -1,3 +1,22 @@
+2011-09-16  Ulan Degenbaev  <ulan@chromium.org>
+
+        [V8] REGRESSION(94783): calling the binding script during V8 context creation slows down page loads
+        https://bugs.webkit.org/show_bug.cgi?id=68237
+
+        Reviewed by Kenneth Russell.
+
+        Call the binding script lazily on the first run of the set() method of
+        a typed array.
+
+        * ../../Source/WebCore/WebCore.gypi:
+        * ../../Source/WebCore/bindings/v8/V8BindingScripts.cpp: Removed.
+        * ../../Source/WebCore/bindings/v8/V8BindingScripts.h: Removed.
+        * ../../Source/WebCore/bindings/v8/V8DOMWindowShell.cpp:
+        * ../../Source/WebCore/bindings/v8/WorkerContextExecutionProxy.cpp:
+        * ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.cpp:
+        * ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.h:
+        * ../../Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustomScript.js:
+
 2011-09-16  Martin Robinson  <mrobinson@igalia.com>
 
         [GTK] Disable WebKit2 by default in configure.ac, but enable it with build-webkit

Source/WebCore/WebCore.gypi

@@ -2063,8 +2063,6 @@
             'bindings/v8/V8AbstractEventListener.h',
             'bindings/v8/V8Binding.cpp',
             'bindings/v8/V8Binding.h',
-            'bindings/v8/V8BindingScripts.cpp',
-            'bindings/v8/V8BindingScripts.h',
             'bindings/v8/V8Collection.cpp',
             'bindings/v8/V8Collection.h',
             'bindings/v8/V8DOMMap.cpp',

Source/WebCore/bindings/v8/V8DOMWindowShell.cpp

@@ -46,7 +46,6 @@
 #include "SecurityOrigin.h"
 #include "StorageNamespace.h"
 #include "V8Binding.h"
-#include "V8BindingScripts.h"
 #include "V8BindingState.h"
 #include "V8Collection.h"
 #include "V8DOMMap.h"
@@ -340,8 +339,6 @@ bool V8DOMWindowShell::initContextIfNeeded()
 
     setSecurityToken();
 
-    V8BindingScripts::runScripts(v8Context);
-
     m_frame->loader()->client()->didCreateScriptContextForFrame();
 
     // FIXME: This is wrong. We should actually do this for the proper world once

Source/WebCore/bindings/v8/WorkerContextExecutionProxy.cpp

@@ -41,7 +41,6 @@
 #include "SharedWorker.h"
 #include "SharedWorkerContext.h"
 #include "V8Binding.h"
-#include "V8BindingScripts.h"
 #include "V8DOMMap.h"
 #include "V8DedicatedWorkerContext.h"
 #include "V8Proxy.h"
@@ -176,8 +175,6 @@ bool WorkerContextExecutionProxy::initContextIfNeeded()
     v8::Handle<v8::Object> globalObject = v8::Handle<v8::Object>::Cast(m_context->Global()->GetPrototype());
     globalObject->SetPrototype(jsWorkerContext);
 
-    V8BindingScripts::runScripts(context);
-
     return true;
 }
 

Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.cpp

@@ -26,10 +26,39 @@
 #include "config.h"
 #include "V8ArrayBufferViewCustom.h"
 
+#include "V8ArrayBufferViewCustomScript.h"
 #include <v8.h>
 
+
 namespace WebCore {
 
+const char fastSetFlagName[] = "webgl::FastSetFlag";
+
+bool fastSetInstalled(v8::Handle<v8::Object> array)
+{
+    // Use a hidden flag in the common prototype (ArrayBufferView) of all typed
+    // arrays as an indicator of whether the fast 'set' is installed or not.
+    v8::Handle<v8::Object> prototype = array->GetPrototype().As<v8::Object>();
+    v8::Handle<v8::Object> arrayBufferView = prototype->GetPrototype().As<v8::Object>();
+    v8::Handle<v8::String> key = v8::String::New(fastSetFlagName);
+    v8::Handle<v8::Value> fastSetFlag = arrayBufferView->GetHiddenValue(key);
+    return !fastSetFlag.IsEmpty();
+}
+
+void installFastSet(v8::Handle<v8::Object> array)
+{
+    v8::Handle<v8::Object> prototype = array->GetPrototype().As<v8::Object>();
+    v8::Handle<v8::Object> arrayBufferView = prototype->GetPrototype().As<v8::Object>();
+    v8::Handle<v8::String> key = v8::String::New(fastSetFlagName);
+    arrayBufferView->SetHiddenValue(key, v8::Boolean::New(true));
+
+    String source(reinterpret_cast<const char*>(V8ArrayBufferViewCustomScript_js),
+                  sizeof(V8ArrayBufferViewCustomScript_js));
+    v8::Handle<v8::Script> script = v8::Script::Compile(v8String(source));
+    script->Run();
+}
+
+
 void copyElements(v8::Handle<v8::Object> destArray, v8::Handle<v8::Object> srcArray)
 {
     v8::Handle<v8::String> key = v8::String::New("set");

Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustom.h

@@ -41,10 +41,19 @@
 namespace WebCore {
 
 
+// Check if the JavaScript 'set' method was already installed
+// on the prototype of the given typed array.
+bool fastSetInstalled(v8::Handle<v8::Object> array);
+
+// Install the JavaScript 'set' method on the prototype of
+// the given typed array.
+void installFastSet(v8::Handle<v8::Object> array);
+
 // Copy the elements from the source array to the typed destination array by
 // invoking the 'set' method of the destination array in JS.
 void copyElements(v8::Handle<v8::Object> destArray, v8::Handle<v8::Object> srcArray);
 
+
 // Template function used by the ArrayBufferView*Constructor callbacks.
 template<class ArrayClass, class ElementType>
 v8::Handle<v8::Value> constructWebGLArrayWithArrayBufferArgument(const v8::Arguments& args, WrapperTypeInfo* type, v8::ExternalArrayType arrayType, bool hasIndexer)
@@ -198,10 +207,15 @@ v8::Handle<v8::Value> setWebGLArrayHelper(const v8::Arguments& args)
             || offset + length < offset)
             // Out of range offset or overflow
             V8Proxy::setDOMException(INDEX_SIZE_ERR);
-        else
-            for (uint32_t i = 0; i < length; i++)
-                impl->set(offset + i, array->Get(i)->NumberValue());
-
+        else {
+            if (!fastSetInstalled(args.Holder())) {
+                installFastSet(args.Holder());
+                copyElements(args.Holder(), array);
+            } else {
+                for (uint32_t i = 0; i < length; i++)
+                    impl->set(offset + i, array->Get(i)->NumberValue());
+            }
+        }
         return v8::Undefined();
     }
 

Source/WebCore/bindings/v8/custom/V8ArrayBufferViewCustomScript.js

@@ -41,6 +41,7 @@ var optimizeSetMethod = function(type)
             } else
                 return nativeSet.call(this, source, offset);
         }
+        f.name = "set";
         return f;
     })();
 };