Encapsulate the unit data in CompilationUnit

This allows updating the constants table when the unit data is set /
changes and removes the tie to the engine.

Change-Id: Ice553650390589e30e18421c4e55422a55d0df89
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

6 files changed, 47 insertions, 27 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 04a7854d56..0461299866 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -1584,7 +1584,7 @@ QV4::CompiledData::Unit *QmlUnitGenerator::generate(Document &output, const QV4:
     char *data = (char*)malloc(totalSize);
     memcpy(data, jsUnit, unitSize);
     memset(data + unitSize, 0, totalSize - unitSize);
-    if (jsUnit != compilationUnit->data)
+    if (jsUnit != compilationUnit->unitData())
         free(jsUnit);
     jsUnit = nullptr;
 
diff --git a/src/qml/compiler/qqmlpropertyvalidator.cpp b/src/qml/compiler/qqmlpropertyvalidator.cpp
index 7daf2f1f2f..7ae88cf80c 100644
--- a/src/qml/compiler/qqmlpropertyvalidator.cpp
+++ b/src/qml/compiler/qqmlpropertyvalidator.cpp
@@ -49,7 +49,7 @@ QQmlPropertyValidator::QQmlPropertyValidator(QQmlEnginePrivate *enginePrivate, c
     : enginePrivate(enginePrivate)
     , compilationUnit(compilationUnit)
     , imports(imports)
-    , qmlUnit(compilationUnit->data)
+    , qmlUnit(compilationUnit->unitData())
     , resolvedTypes(compilationUnit->resolvedTypes)
     , propertyCaches(compilationUnit->propertyCaches)
     , bindingPropertyDataPerObject(&compilationUnit->bindingPropertyDataPerObject)
diff --git a/src/qml/compiler/qqmltypecompiler.cpp b/src/qml/compiler/qqmltypecompiler.cpp
index 0d338c8b7e..6582a9ca6b 100644
--- a/src/qml/compiler/qqmltypecompiler.cpp
+++ b/src/qml/compiler/qqmltypecompiler.cpp
@@ -161,14 +161,14 @@ QQmlRefPointer<QV4::CompiledData::CompilationUnit> QQmlTypeCompiler::compile()
 
     Q_ASSERT(document->javaScriptCompilationUnit);
     // The js unit owns the data and will free the qml unit.
-    document->javaScriptCompilationUnit->data = qmlUnit;
+    document->javaScriptCompilationUnit->setUnitData(qmlUnit);
 
     QQmlRefPointer<QV4::CompiledData::CompilationUnit> compilationUnit = document->javaScriptCompilationUnit;
     compilationUnit = document->javaScriptCompilationUnit;
     compilationUnit->typeNameCache = typeNameCache;
     compilationUnit->resolvedTypes = resolvedTypes;
     compilationUnit->propertyCaches = std::move(m_propertyCaches);
-    Q_ASSERT(compilationUnit->propertyCaches.count() == static_cast<int>(compilationUnit->data->nObjects));
+    Q_ASSERT(compilationUnit->propertyCaches.count() == static_cast<int>(compilationUnit->unitData()->nObjects));
 
     if (errors.isEmpty())
         return compilationUnit;
@@ -209,7 +209,7 @@ int QQmlTypeCompiler::registerString(const QString &str)
 
 const QV4::CompiledData::Unit *QQmlTypeCompiler::qmlUnit() const
 {
-    return document->javaScriptCompilationUnit->data;
+    return document->javaScriptCompilationUnit->unitData();
 }
 
 const QQmlImports *QQmlTypeCompiler::imports() const
diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index b0e9d4ce66..c81ea09cce 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -3534,9 +3534,10 @@ QList<QQmlJS::DiagnosticMessage> Codegen::errors() const
 
 QQmlRefPointer<CompiledData::CompilationUnit> Codegen::generateCompilationUnit(bool generateUnitData)
 {
-    CompiledData::CompilationUnit *compilationUnit = new CompiledData::CompilationUnit;
+    CompiledData::Unit *unitData = nullptr;
     if (generateUnitData)
-        compilationUnit->data = jsUnitGenerator->generateUnit();
+        unitData = jsUnitGenerator->generateUnit();
+    CompiledData::CompilationUnit *compilationUnit = new CompiledData::CompilationUnit(unitData);
 
     QQmlRefPointer<CompiledData::CompilationUnit> unit;
     unit.adopt(compilationUnit);
diff --git a/src/qml/compiler/qv4compileddata.cpp b/src/qml/compiler/qv4compileddata.cpp
index 0c81a5b3c6..a4c7c98642 100644
--- a/src/qml/compiler/qv4compileddata.cpp
+++ b/src/qml/compiler/qv4compileddata.cpp
@@ -64,6 +64,7 @@
 #include <QCoreApplication>
 #include <QCryptographicHash>
 #include <QSaveFile>
+#include <QScopeGuard>
 
 // generated by qmake:
 #include "qml_compile_hash_p.h"
@@ -91,7 +92,7 @@ static_assert(sizeof(Unit::libraryVersionHash) >= QML_COMPILE_HASH_LENGTH + 1, "
 
 CompilationUnit::CompilationUnit(const Unit *unitData)
 {
-    data = unitData;
+    setUnitData(unitData);
 }
 
 #ifndef V4_BOOTSTRAP
@@ -101,6 +102,10 @@ CompilationUnit::~CompilationUnit()
     if (data && !(data->flags & QV4::CompiledData::Unit::StaticData))
         free(const_cast<Unit *>(data));
     data = nullptr;
+#if Q_BYTE_ORDER == Q_BIG_ENDIAN
+    delete [] constants;
+    constants = nullptr;
+#endif
 }
 
 QString CompilationUnit::localCacheFilePath(const QUrl &url)
@@ -175,16 +180,6 @@ QV4::Function *CompilationUnit::linkToEngine(ExecutionEngine *engine)
         }
     }
 
-#if Q_BYTE_ORDER == Q_BIG_ENDIAN
-    Value *bigEndianConstants = new Value[data->constantTableSize];
-    const quint64_le *littleEndianConstants = data->constants();
-    for (uint i = 0; i < data->constantTableSize; ++i)
-        bigEndianConstants[i] = Value::fromReturnedValue(littleEndianConstants[i]);
-    constants = bigEndianConstants;
-#else
-    constants = reinterpret_cast<const Value*>(data->constants());
-#endif
-
     linkBackendToEngine(engine);
 
     static const bool showCode = qEnvironmentVariableIsSet("QV4_SHOW_BYTECODE");
@@ -240,10 +235,6 @@ void CompilationUnit::unlink()
     runtimeClasses = nullptr;
     qDeleteAll(runtimeFunctions);
     runtimeFunctions.clear();
-#if Q_BYTE_ORDER == Q_BIG_ENDIAN
-    delete [] constants;
-    constants = nullptr;
-#endif
 }
 
 void CompilationUnit::markObjects(QV4::MarkStack *markStack)
@@ -369,14 +360,18 @@ bool CompilationUnit::loadFromDisk(const QUrl &url, const QDateTime &sourceTimeS
             continue;
 
         const Unit * const oldDataPtr = (data && !(data->flags & QV4::CompiledData::Unit::StaticData)) ? data : nullptr;
-        QScopedValueRollback<const Unit *> dataPtrChange(data, mappedUnit);
+        const Unit *oldData = data;
+        auto dataPtrRevert = qScopeGuard([this, oldData](){
+            setUnitData(oldData);
+        });
+        setUnitData(mappedUnit);
 
         if (data->sourceFileIndex != 0 && sourcePath != QQmlFile::urlToLocalFileOrQrc(stringAt(data->sourceFileIndex))) {
             *errorString = QStringLiteral("QML source file has moved to a different location.");
             continue;
         }
 
-        dataPtrChange.commit();
+        dataPtrRevert.dismiss();
         free(const_cast<Unit*>(oldDataPtr));
         backingFile.reset(cacheFile.take());
         return true;
@@ -572,6 +567,27 @@ Unit *CompilationUnit::createUnitData(QmlIR::Document *irDocument)
     return jsUnit;
 }
 
+void CompilationUnit::setUnitData(const Unit *unitData)
+{
+    data = unitData;
+#if Q_BYTE_ORDER == Q_BIG_ENDIAN
+    delete [] constants;
+#endif
+    constants = nullptr;
+    if (!data)
+        return;
+
+#if Q_BYTE_ORDER == Q_BIG_ENDIAN
+    Value *bigEndianConstants = new Value[data->constantTableSize];
+    const quint64_le *littleEndianConstants = data->constants();
+    for (uint i = 0; i < data->constantTableSize; ++i)
+        bigEndianConstants[i] = Value::fromReturnedValue(littleEndianConstants[i]);
+    constants = bigEndianConstants;
+#else
+    constants = reinterpret_cast<const Value*>(data->constants());
+#endif
+}
+
 QString Binding::valueAsString(const Unit *unit) const
 {
     switch (type) {
@@ -697,7 +713,7 @@ bool ResolvedTypeReference::addToHash(QCryptographicHash *hash, QQmlEngine *engi
         hash->addData(createPropertyCache(engine)->checksum(&ok));
         return ok;
     }
-    hash->addData(compilationUnit->data->md5Checksum, sizeof(compilationUnit->data->md5Checksum));
+    hash->addData(compilationUnit->unitData()->md5Checksum, sizeof(compilationUnit->unitData()->md5Checksum));
     return true;
 }
 
diff --git a/src/qml/compiler/qv4compileddata_p.h b/src/qml/compiler/qv4compileddata_p.h
index 5103c6901e..31e83e8f76 100644
--- a/src/qml/compiler/qv4compileddata_p.h
+++ b/src/qml/compiler/qv4compileddata_p.h
@@ -982,7 +982,6 @@ struct Q_QML_PRIVATE_EXPORT CompilationUnitBase
     QV4::Heap::String **runtimeStrings = nullptr; // Array
     const Value* constants = nullptr;
     QV4::Value *runtimeRegularExpressions = nullptr;
-    const Unit *data = nullptr;
     QV4::Heap::InternalClass **runtimeClasses = nullptr;
 };
 
@@ -993,6 +992,7 @@ Q_STATIC_ASSERT(offsetof(CompilationUnitBase, runtimeRegularExpressions) == offs
 
 struct Q_QML_PRIVATE_EXPORT CompilationUnit final : public CompilationUnitBase
 {
+    const Unit *data = nullptr;
 public:
     CompilationUnit(const Unit *unitData = nullptr);
 #ifdef V4_BOOTSTRAP
@@ -1019,7 +1019,10 @@ public:
     }
 
     // Called only when building QML, when we build the header for JS first and append QML data
-    QV4::CompiledData::Unit *createUnitData(QmlIR::Document *irDocument);
+    Unit *createUnitData(QmlIR::Document *irDocument);
+
+    const Unit *unitData() const { return data; }
+    void setUnitData(const Unit *unitData);
 
 #ifndef V4_BOOTSTRAP
     QIntrusiveListNode nextCompilationUnit;