Reduce the size of Property fields in type compilation data

We can shave off 4 bytes of each property declaration by sharing the
bits for the custom type name index or the builtin type enum.

Change-Id: I77071cbef66c5a83b3e7e281dba3a435d3c68b39
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

2 files changed, 33 insertions, 23 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 8bdbab3b5a..6c61473418 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -872,13 +872,15 @@ bool IRBuilder::visit(QQmlJS::AST::UiPublicMember *node)
         } else {
             const QStringRef &name = node->name;
 
+            Property *property = New<Property>();
+            property->isReadOnly = node->isReadonlyMember;
+
             bool typeFound = false;
-            QV4::CompiledData::Property::Type type = QV4::CompiledData::Property::Var;
 
             for (int ii = 0; !typeFound && ii < propTypeNameToTypesCount; ++ii) {
                 const TypeNameToType *t = propTypeNameToTypes + ii;
                 if (memberType == QLatin1String(t->name, static_cast<int>(t->nameLength))) {
-                    type = t->type;
+                    property->setBuiltinType(t->type);
                     typeFound = true;
                 }
             }
@@ -886,11 +888,10 @@ bool IRBuilder::visit(QQmlJS::AST::UiPublicMember *node)
             if (!typeFound && memberType.at(0).isUpper()) {
                 const QStringRef &typeModifier = node->typeModifier;
 
-                if (typeModifier.isEmpty()) {
-                    type = QV4::CompiledData::Property::Custom;
-                } else if (typeModifier == QLatin1String("list")) {
-                    type = QV4::CompiledData::Property::CustomList;
-                } else {
+                property->setCustomType(registerString(memberType));
+                if (typeModifier == QLatin1String("list")) {
+                    property->isList = true;
+                } else if (!typeModifier.isEmpty()) {
                     recordError(node->typeModifierToken, QCoreApplication::translate("QQmlParser","Invalid property type modifier"));
                     return false;
                 }
@@ -905,14 +906,6 @@ bool IRBuilder::visit(QQmlJS::AST::UiPublicMember *node)
                 return false;
             }
 
-            Property *property = New<Property>();
-            property->isReadOnly = node->isReadonlyMember;
-            property->type = type;
-            if (type >= QV4::CompiledData::Property::Custom)
-                property->customTypeNameIndex = registerString(memberType);
-            else
-                property->customTypeNameIndex = emptyStringIndex;
-
             const QString propName = name.toString();
             property->nameIndex = registerString(propName);
 
@@ -1530,7 +1523,7 @@ bool IRBuilder::isStatementNodeScript(QQmlJS::AST::Statement *statement)
 
 bool IRBuilder::isRedundantNullInitializerForPropertyDeclaration(Property *property, QQmlJS::AST::Statement *statement)
 {
-    if (property->type != QV4::CompiledData::Property::Custom)
+    if (property->isBuiltinType || property->isList)
         return false;
     QQmlJS::AST::ExpressionStatement *exprStmt = QQmlJS::AST::cast<QQmlJS::AST::ExpressionStatement *>(statement);
     if (!exprStmt)
diff --git a/src/qml/compiler/qv4compileddata_p.h b/src/qml/compiler/qv4compileddata_p.h
index 9123f9f0ec..639595509a 100644
--- a/src/qml/compiler/qv4compileddata_p.h
+++ b/src/qml/compiler/qv4compileddata_p.h
@@ -642,18 +642,35 @@ struct Property
 {
     enum Type : unsigned int { Var = 0, Variant, Int, Bool, Real, String, Url, Color,
                 Font, Time, Date, DateTime, Rect, Point, Size,
-                Vector2D, Vector3D, Vector4D, Matrix4x4, Quaternion,
-                Custom, CustomList };
+                Vector2D, Vector3D, Vector4D, Matrix4x4, Quaternion, InvalidBuiltin };
 
     quint32_le nameIndex;
     union {
-        quint32_le_bitfield<0, 31> type;
+        quint32_le_bitfield<0, 29> builtinTypeOrTypeNameIndex;
+        quint32_le_bitfield<29, 1> isBuiltinType;
+        quint32_le_bitfield<30, 1> isList;
         quint32_le_bitfield<31, 1> isReadOnly;
     };
-    quint32_le customTypeNameIndex; // If type >= Custom
+
     Location location;
+
+    void setBuiltinType(Type t)
+    {
+        builtinTypeOrTypeNameIndex = t;
+        isBuiltinType = true;
+    }
+    Type builtinType() const {
+        if (isBuiltinType)
+            return static_cast<Type>(quint32(builtinTypeOrTypeNameIndex));
+        return InvalidBuiltin;
+    }
+    void setCustomType(int nameIndex)
+    {
+        builtinTypeOrTypeNameIndex = nameIndex;
+        isBuiltinType = false;
+    }
 };
-static_assert(sizeof(Property) == 16, "Property structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
+static_assert(sizeof(Property) == 12, "Property structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
 
 struct Alias {
     enum Flags : unsigned int {
@@ -1044,8 +1061,8 @@ struct TypeReferenceMap : QHash<int, TypeReference>
         auto prop = obj->propertiesBegin();
         auto propEnd = obj->propertiesEnd();
         for ( ; prop != propEnd; ++prop) {
-            if (prop->type >= QV4::CompiledData::Property::Custom) {
-                TypeReference &r = this->add(prop->customTypeNameIndex, prop->location);
+            if (!prop->isBuiltinType) {
+                TypeReference &r = this->add(prop->builtinTypeOrTypeNameIndex, prop->location);
                 r.errorWhenNotFound = true;
             }
         }