Rewrite bindings inside the compiler

To improve execution performance, binding expressions are rewritten as function
closures inside QmlExpression.  To improve startup performance, where possible,
the expressions are rewritten inside the compiler instead of inside
QmlExpression at runtime.

This also has the sideeffect of removing the StoreBinding instruction, as all
bindings are now "compiled".  The QmlBinding::expression() method for rewritten
bindings will now return the rewritten expression instead of the original (which
is lost), but this API is internal anyway.

1 files changed, 28 insertions, 15 deletions

diff --git a/src/declarative/qml/qmlcompiler.cpp b/src/declarative/qml/qmlcompiler.cpp
index 197bd44..6ef7cc2 100644
--- a/src/declarative/qml/qmlcompiler.cpp
+++ b/src/declarative/qml/qmlcompiler.cpp
@@ -64,7 +64,9 @@
 #include <private/qmlcomponent_p.h>
 #include "parser/qmljsast_p.h"
 #include <private/qmlvmemetaobject_p.h>
+#include <private/qmlexpression_p.h>
 #include "qmlmetaproperty_p.h"
+#include "qmlrewrite_p.h"
 
 #include "qmlscriptparser_p.h"
 
@@ -2062,14 +2064,11 @@ void QmlCompiler::genBindingAssignment(QmlParser::Value *binding,
     const BindingReference &ref = compileState.bindings.value(binding);
 
     QmlInstruction store;
-    int dataRef;
-    if (ref.compiledData.isEmpty()) {
-        dataRef = output->indexForString(ref.expression.asScript());
-        store.type = QmlInstruction::StoreBinding;
-    } else {
-        dataRef = output->indexForByteArray(ref.compiledData);
-        store.type = QmlInstruction::StoreCompiledBinding;
-    }
+    store.type = QmlInstruction::StoreCompiledBinding;
+    store.assignBinding.value = output->indexForByteArray(ref.compiledData);
+    store.assignBinding.context = ref.bindingContext.stack;
+    store.assignBinding.owner = ref.bindingContext.owner;
+    store.line = prop->location.end.line;
 
     Q_ASSERT(ref.bindingContext.owner == 0 ||
              (ref.bindingContext.owner != 0 && valueTypeProperty));
@@ -2081,18 +2080,12 @@ void QmlCompiler::genBindingAssignment(QmlParser::Value *binding,
         store.assignBinding.property =
             QmlMetaPropertyPrivate::saveProperty(prop->index);
     }
-    store.assignBinding.value = dataRef;
-    store.assignBinding.context = ref.bindingContext.stack;
-    store.assignBinding.owner = ref.bindingContext.owner;
-    store.line = prop->location.end.line;
 
     output->bytecode << store;
 }
 
 bool QmlCompiler::completeComponentBuild()
 {
-    saveComponentState();
-
     for (int ii = 0; ii < compileState.aliasingObjects.count(); ++ii) {
         Object *aliasObject = compileState.aliasingObjects.at(ii);
         COMPILE_CHECK(buildDynamicMeta(aliasObject, ResolveAliases));
@@ -2111,11 +2104,31 @@ bool QmlCompiler::completeComponentBuild()
         expr.expression = binding.expression;
 
         bs.compile(expr);
-        if (bs.isValid())
+        quint32 type;
+        if (bs.isValid()) {
             binding.compiledData =
                 QByteArray(bs.compileData(), bs.compileDataSize());
+            type = QmlExpressionPrivate::BasicScriptEngineData;
+        } else {
+            type = QmlExpressionPrivate::PreTransformedQtScriptData;
+
+            // Pre-rewrite the expression
+            QString expression = binding.expression.asScript();
+            QmlRewrite::RewriteBinding rewriteBinding;
+            expression = rewriteBinding(expression);
+
+            quint32 length = expression.length();
+            binding.compiledData =
+                QByteArray((const char *)&length, sizeof(quint32)) +
+                QByteArray((const char *)expression.constData(), 
+                           expression.length() * sizeof(QChar));
+        }
+        binding.compiledData.prepend(QByteArray((const char *)&type, 
+                                                sizeof(quint32)));
     }
 
+    saveComponentState();
+
     return true;
 }