optimize string usage: use fromLatin1() less

.. to reduce allocations.

Replace fromLatin1 with QLatin1String or
with QStringBuilder where it is possible.

Change-Id: I09c7242fa7b118447b51239e2a6743a34fb3de14
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

2 files changed, 9 insertions, 8 deletions

diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index 9462101a2a..870782c306 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -1302,9 +1302,8 @@ static QV4::ReturnedValue CallPrecise(const QQmlObjectOrGadget &object, const QQ
     int returnType = object.methodReturnType(data, &unknownTypeError);
 
     if (returnType == QMetaType::UnknownType) {
-        QString typeName = QString::fromLatin1(unknownTypeError);
-        QString error = QStringLiteral("Unknown method return type: %1").arg(typeName);
-        return engine->throwError(error);
+        return engine->throwError(QLatin1String("Unknown method return type: ")
+                                  + QLatin1String(unknownTypeError));
     }
 
     if (data.hasArguments()) {
@@ -1319,9 +1318,8 @@ static QV4::ReturnedValue CallPrecise(const QQmlObjectOrGadget &object, const QQ
             args = object.methodParameterTypes(data.coreIndex(), &storage, &unknownTypeError);
 
         if (!args) {
-            QString typeName = QString::fromLatin1(unknownTypeError);
-            QString error = QStringLiteral("Unknown method parameter type: %1").arg(typeName);
-            return engine->throwError(error);
+            return engine->throwError(QLatin1String("Unknown method parameter type: ")
+                                      + QLatin1String(unknownTypeError));
         }
 
         if (args[0] > callArgs->argc) {
diff --git a/src/qml/jsruntime/qv4variantobject.cpp b/src/qml/jsruntime/qv4variantobject.cpp
index 444c0a37e0..39b41dd0d8 100644
--- a/src/qml/jsruntime/qv4variantobject.cpp
+++ b/src/qml/jsruntime/qv4variantobject.cpp
@@ -138,8 +138,11 @@ QV4::ReturnedValue VariantPrototype::method_toString(CallContext *ctx)
     if (!o)
         return Encode::undefined();
     QString result = o->d()->data.toString();
-    if (result.isEmpty() && !o->d()->data.canConvert(QVariant::String))
-        result = QStringLiteral("QVariant(%0)").arg(QString::fromLatin1(o->d()->data.typeName()));
+    if (result.isEmpty() && !o->d()->data.canConvert(QVariant::String)) {
+        result = QLatin1String("QVariant(")
+                 + QLatin1String(o->d()->data.typeName())
+                 + QLatin1Char(')');
+    }
     return Encode(ctx->d()->engine->newString(result));
 }