Speed up creation of Array literals

Gives around 10% speedup on the v8 splay benchmark.

Change-Id: I47f64e7b73bde59ac3bdd2c94fc199ecfbbf290e
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

3 files changed, 22 insertions, 9 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index e306106aea..d5a47273a9 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -618,6 +618,26 @@ Heap::ArrayObject *ExecutionEngine::newArrayObject(int count)
     return object->d();
 }
 
+Heap::ArrayObject *ExecutionEngine::newArrayObject(const Value *values, int length)
+{
+    Scope scope(this);
+    ScopedArrayObject a(scope, memoryManager->allocObject<ArrayObject>());
+
+    if (length) {
+        size_t size = sizeof(Heap::ArrayData) + (length-1)*sizeof(Value);
+        Heap::SimpleArrayData *d = scope.engine->memoryManager->allocManaged<SimpleArrayData>(size);
+        new (d) Heap::SimpleArrayData;
+        d->alloc = length;
+        d->type = Heap::ArrayData::Simple;
+        d->offset = 0;
+        d->len = length;
+        memcpy(&d->arrayData, values, length*sizeof(Value));
+        a->d()->arrayData = d;
+        a->setArrayLengthUnchecked(length);
+    }
+    return a->d();
+}
+
 Heap::ArrayObject *ExecutionEngine::newArrayObject(const QStringList &list)
 {
     Scope scope(this);
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 447105c2ab..ef9d83cea3 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -373,6 +373,7 @@ public:
     Heap::Object *newBooleanObject(bool b);
 
     Heap::ArrayObject *newArrayObject(int count = 0);
+    Heap::ArrayObject *newArrayObject(const Value *values, int length);
     Heap::ArrayObject *newArrayObject(const QStringList &list);
     Heap::ArrayObject *newArrayObject(InternalClass *ic, Object *prototype);
 
diff --git a/src/qml/jsruntime/qv4runtime.cpp b/src/qml/jsruntime/qv4runtime.cpp
index d122f06d05..0d7a1851b8 100644
--- a/src/qml/jsruntime/qv4runtime.cpp
+++ b/src/qml/jsruntime/qv4runtime.cpp
@@ -1209,15 +1209,7 @@ void Runtime::declareVar(ExecutionEngine *engine, bool deletable, int nameIndex)
 
 ReturnedValue Runtime::arrayLiteral(ExecutionEngine *engine, Value *values, uint length)
 {
-    Scope scope(engine);
-    ScopedArrayObject a(scope, engine->newArrayObject());
-
-    if (length) {
-        a->arrayReserve(length);
-        a->arrayPut(0, values, length);
-        a->setArrayLengthUnchecked(length);
-    }
-    return a.asReturnedValue();
+    return engine->newArrayObject(values, length)->asReturnedValue();
 }
 
 ReturnedValue Runtime::objectLiteral(ExecutionEngine *engine, const QV4::Value *args, int classId, int arrayValueCount, int arrayGetterSetterCountAndFlags)