QmlCompiler: Perform return value assignment inside generated code

This is in preparation for using exact types and actually enforcing
them. We shouldn't wrap the return value into a QVariant in order to
then painstakingly unwrap it again. The generated code can already do
the right thing.

Task-number: QTBUG-119885
Change-Id: I13e517967ee982be717024a9abb74d5e02a185d6
Reviewed-by: Olivier De Cannière <olivier.decanniere@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

6 files changed, 76 insertions, 78 deletions

diff --git a/src/qml/common/qv4compileddata_p.h b/src/qml/common/qv4compileddata_p.h
index 784e3e5444..caedd8928e 100644
--- a/src/qml/common/qv4compileddata_p.h
+++ b/src/qml/common/qv4compileddata_p.h
@@ -51,7 +51,7 @@ QT_BEGIN_NAMESPACE
 // Also change the comment behind the number to describe the latest change. This has the added
 // benefit that if another patch changes the version too, it will result in a merge conflict, and
 // not get removed silently.
-#define QV4_DATA_STRUCTURE_VERSION 0x40 // Switch the "sticky" and "unicode" regexp flags
+#define QV4_DATA_STRUCTURE_VERSION 0x41 // Change signature of AOT compiled functions
 
 class QIODevice;
 class QQmlTypeNameCache;
diff --git a/src/qml/jsruntime/qv4vme_moth.cpp b/src/qml/jsruntime/qv4vme_moth.cpp
index 696368fa3f..db17a7141c 100644
--- a/src/qml/jsruntime/qv4vme_moth.cpp
+++ b/src/qml/jsruntime/qv4vme_moth.cpp
@@ -443,7 +443,7 @@ void VME::exec(MetaTypesStackFrame *frame, ExecutionEngine *engine)
 
         aotContext.engine = engine->jsEngine();
         aotContext.compilationUnit = function->executableCompilationUnit();
-        function->aotCompiledFunction->functionPtr(&aotContext, argv[0], argv + 1);
+        function->aotCompiledFunction->functionPtr(&aotContext, argv);
     });
 }
 
diff --git a/src/qml/qml/qqmlprivate.h b/src/qml/qml/qqmlprivate.h
index f5e1feb4f2..25dc36d33d 100644
--- a/src/qml/qml/qqmlprivate.h
+++ b/src/qml/qml/qqmlprivate.h
@@ -743,7 +743,7 @@ namespace QQmlPrivate
         qintptr extraData;
         QMetaType returnType;
         QList<QMetaType> argumentTypes;
-        void (*functionPtr)(const AOTCompiledContext *context, void *resultPtr, void **arguments);
+        void (*functionPtr)(const AOTCompiledContext *context, void **argv);
     };
 
 #if QT_DEPRECATED_SINCE(6, 6)
diff --git a/src/qmlcompiler/qqmljscodegenerator.cpp b/src/qmlcompiler/qqmljscodegenerator.cpp
index 0e5fbdea12..65387e3681 100644
--- a/src/qmlcompiler/qqmljscodegenerator.cpp
+++ b/src/qmlcompiler/qqmljscodegenerator.cpp
@@ -209,7 +209,7 @@ QT_WARNING_POP
 
             const QString originalValue
                     = u"(*static_cast<"_s + castTargetName(original.storedType())
-                    + u"*>(argumentsPtr["_s + QString::number(argumentIndex) + u"]))"_s;
+                    + u"*>(argv["_s + QString::number(argumentIndex + 1) + u"]))"_s;
 
             if (needsConversion)
                 result.code += conversion(original, argument, originalValue);
@@ -244,55 +244,71 @@ QT_WARNING_POP
     return result;
 }
 
-QString QQmlJSCodeGenerator::errorReturnValue()
+void QQmlJSCodeGenerator::generateReturnError()
 {
-    if (auto ret = m_function->returnType) {
-        return ret->accessSemantics() == QQmlJSScope::AccessSemantics::Reference
-                ? convertStored(m_typeResolver->nullType(), ret, QString())
-                : ret->internalName() + u"()"_s;
-    }
-    return QString();
+    const auto finalizeReturn = qScopeGuard([this]() { m_body += u"return;\n"_s; });
+
+    m_body += u"aotContext->setReturnValueUndefined();\n"_s;
+    const auto ret = m_function->returnType;
+    if (!ret || m_typeResolver->equals(m_function->returnType, m_typeResolver->voidType()))
+        return;
+
+    const QString value = ret->accessSemantics() == QQmlJSScope::AccessSemantics::Reference
+            ? convertStored(m_typeResolver->nullType(), ret, QString())
+            : ret->internalName() + u"()"_s;
+
+    m_body += u"if (argv[0]) {\n"_s;
+    m_body += u"    *static_cast<"_s + m_function->returnType->augmentedInternalName()
+            + u" *>(argv[0]) = "_s + value + u";\n"_s;
+    m_body += u"}\n"_s;
 }
 
 void QQmlJSCodeGenerator::generate_Ret()
 {
     INJECT_TRACE_INFO(generate_Ret);
 
-    if (m_function->returnType) {
-        const QString signalUndefined = u"aotContext->setReturnValueUndefined();\n"_s;
-        if (!m_state.accumulatorVariableIn.isEmpty()) {
-            const QString in = m_state.accumulatorVariableIn;
-            if (m_typeResolver->registerIsStoredIn(
-                        m_state.accumulatorIn(), m_typeResolver->varType())) {
-                m_body += u"if (!"_s + in + u".isValid())\n"_s;
-                m_body += u"    "_s + signalUndefined;
-            } else if (m_typeResolver->registerIsStoredIn(
-                           m_state.accumulatorIn(), m_typeResolver->jsPrimitiveType())) {
-                m_body += u"if ("_s + in
-                        + u".type() == QJSPrimitiveValue::Undefined)\n"_s;
-                m_body += u"    "_s + signalUndefined;
-            } else if (m_typeResolver->registerIsStoredIn(
-                           m_state.accumulatorIn(), m_typeResolver->jsValueType())) {
-                m_body += u"if ("_s + in + u".isUndefined())\n"_s;
-                m_body += u"    "_s + signalUndefined;
-            }
-            m_body += u"return "_s
-                    + convertStored(m_state.accumulatorIn().storedType(), m_function->returnType, in);
-        } else {
-            if (m_typeResolver->equals(m_state.accumulatorIn().storedType(),
-                                       m_typeResolver->voidType())) {
-                m_body += signalUndefined;
-            }
-            m_body += u"return "_s + convertStored(
-                        m_state.accumulatorIn().storedType(), m_function->returnType, QString());
+    const auto finalizeReturn = qScopeGuard([this]() {
+        m_body += u"return;\n"_s;
+        m_skipUntilNextLabel = true;
+        resetState();
+    });
+
+    if (!m_function->returnType)
+        return;
+
+    m_body += u"if (argv[0]) {\n"_s;
+
+    const QString signalUndefined = u"aotContext->setReturnValueUndefined();\n"_s;
+    const QString in = m_state.accumulatorVariableIn;
+
+    if (in.isEmpty()) {
+        if (m_typeResolver->equals(m_state.accumulatorIn().storedType(),
+                                   m_typeResolver->voidType())) {
+            m_body += signalUndefined;
+
         }
-    } else {
-        m_body += u"return"_s;
+    } else if (m_typeResolver->registerIsStoredIn(
+                    m_state.accumulatorIn(), m_typeResolver->varType())) {
+        m_body += u"    if (!"_s + in + u".isValid())\n"_s;
+        m_body += u"        "_s + signalUndefined;
+    } else if (m_typeResolver->registerIsStoredIn(
+                   m_state.accumulatorIn(), m_typeResolver->jsPrimitiveType())) {
+        m_body += u"    if ("_s + in + u".type() == QJSPrimitiveValue::Undefined)\n"_s;
+        m_body += u"        "_s + signalUndefined;
+    } else if (m_typeResolver->registerIsStoredIn(
+                   m_state.accumulatorIn(), m_typeResolver->jsValueType())) {
+        m_body += u"    if ("_s + in + u".isUndefined())\n"_s;
+        m_body += u"        "_s + signalUndefined;
+    }
+
+    if (!m_typeResolver->equals(m_function->returnType, m_typeResolver->voidType())) {
+        m_body += u"    *static_cast<"_s + m_function->returnType->augmentedInternalName()
+                +u" *>(argv[0]) = "_s + convertStored(
+                      m_state.accumulatorIn().storedType(), m_function->returnType, in)
+                + u";\n"_s;
     }
 
-    m_body += u";\n"_s;
-    m_skipUntilNextLabel = true;
-    resetState();
+    m_body += u"}\n"_s;
 }
 
 void QQmlJSCodeGenerator::generate_Debug()
@@ -1208,7 +1224,7 @@ bool QQmlJSCodeGenerator::generateContentPointerCheck(
     generateSetInstructionPointer();
     m_body += u"    aotContext->engine->throwError(QJSValue::TypeError, "_s;
     m_body += u"QLatin1String(\"%1\"));\n"_s.arg(processedErrorMessage);
-    m_body += u"    return "_s + errorReturnValue() + u";\n"_s;
+    generateReturnError();
     m_body += u"}\n"_s;
     return needsVarContentConversion;
 }
@@ -2302,20 +2318,21 @@ void QQmlJSCodeGenerator::generate_Construct(int func, int argc, int argv)
             addInclude(u"QtQml/qjslist.h"_s);
 
             const QString error = u"    aotContext->engine->throwError(QJSValue::RangeError, "_s
-                    + u"QLatin1String(\"Invalid array length\"));\n"_s
-                    + u"    return "_s + errorReturnValue() + u";\n"_s;
+                    + u"QLatin1String(\"Invalid array length\"));\n"_s;
 
             const QString indexName = registerVariable(argv);
             const auto indexType = registerType(argv);
             if (!m_typeResolver->isIntegral(indexType)) {
                 m_body += u"if (!QJSNumberCoercion::isArrayIndex("_s + indexName + u")) {\n"_s
-                        + error
-                        + u"}\n"_s;
+                        + error;
+                generateReturnError();
+                m_body += u"}\n"_s;
             } else if (!m_typeResolver->isUnsignedInteger(
                                m_typeResolver->containedType(indexType))) {
                 m_body += u"if ("_s + indexName + u" < 0) {\n"_s
-                        + error
-                        + u"}\n"_s;
+                        + error;
+                generateReturnError();
+                m_body += u"}\n"_s;
             }
 
             m_body += m_state.accumulatorVariableOut + u" = "_s
@@ -2378,7 +2395,7 @@ void QQmlJSCodeGenerator::generate_ThrowException()
         + conversion(m_state.accumulatorIn(), m_typeResolver->globalType(
                          m_typeResolver->jsValueType()),
                      m_state.accumulatorVariableIn) + u");\n"_s;
-    m_body += u"return "_s + errorReturnValue() + u";\n"_s;
+    generateReturnError();
     m_skipUntilNextLabel = true;
     resetState();
 }
@@ -3282,8 +3299,9 @@ void QQmlJSCodeGenerator::generateSetInstructionPointer()
 
 void QQmlJSCodeGenerator::generateExceptionCheck()
 {
-    m_body += u"if (aotContext->engine->hasError())\n"_s;
-    m_body += u"    return "_s + errorReturnValue() + u";\n"_s;
+    m_body += u"if (aotContext->engine->hasError()) {\n"_s;
+    generateReturnError();
+    m_body += u"}\n"_s;
 }
 
 void QQmlJSCodeGenerator::generateEqualityOperation(
diff --git a/src/qmlcompiler/qqmljscodegenerator_p.h b/src/qmlcompiler/qqmljscodegenerator_p.h
index 7ed0d08048..33589c13a3 100644
--- a/src/qmlcompiler/qqmljscodegenerator_p.h
+++ b/src/qmlcompiler/qqmljscodegenerator_p.h
@@ -242,7 +242,7 @@ protected:
                              const QQmlJSRegisterContent &to,
                              const QString &variable);
 
-    QString errorReturnValue();
+    void generateReturnError();
     void reject(const QString &thing);
 
     QString metaTypeFromType(const QQmlJSScope::ConstPtr &type) const;
diff --git a/src/qmlcompiler/qqmljscompiler.cpp b/src/qmlcompiler/qqmljscompiler.cpp
index 2cc32fc63d..cca05380c9 100644
--- a/src/qmlcompiler/qqmljscompiler.cpp
+++ b/src/qmlcompiler/qqmljscompiler.cpp
@@ -460,29 +460,10 @@ bool qCompileJSFile(const QString &inputFileName, const QString &inputFileUrl, Q
             QV4::CompiledData::SaveableUnitPointer(unit->unitData()), empty, &error->message);
 }
 
-static const char *wrapCallCode = R"(
-template <typename Binding>
-void wrapCall(const QQmlPrivate::AOTCompiledContext *aotContext, void *dataPtr, void **argumentsPtr, Binding &&binding)
-{
-    using return_type = std::invoke_result_t<Binding, const QQmlPrivate::AOTCompiledContext *, void **>;
-    if constexpr (std::is_same_v<return_type, void>) {
-       Q_UNUSED(dataPtr)
-       binding(aotContext, argumentsPtr);
-    } else {
-        if (dataPtr) {
-           *static_cast<return_type *>(dataPtr) = binding(aotContext, argumentsPtr);
-        } else {
-           binding(aotContext, argumentsPtr);
-        }
-    }
-}
-)";
-
 static const char *funcHeaderCode = R"(
-    [](const QQmlPrivate::AOTCompiledContext *context, void *data, void **argv) {
-        wrapCall(context, data, argv, [](const QQmlPrivate::AOTCompiledContext *aotContext, void **argumentsPtr) {
+    [](const QQmlPrivate::AOTCompiledContext *aotContext, void **argv) {
 Q_UNUSED(aotContext)
-Q_UNUSED(argumentsPtr)
+Q_UNUSED(argv)
 )";
 
 bool qSaveQmlJSUnitAsCpp(const QString &inputFileName, const QString &outputFileName, const QV4::CompiledData::SaveableUnitPointer &unit, const QQmlJSAotFunctionMap &aotFunctions, QString *errorString)
@@ -579,13 +560,12 @@ bool qSaveQmlJSUnitAsCpp(const QString &inputFileName, const QString &outputFile
     if (aotFunctions.size() <= 1) {
         // FileScopeCodeIndex is always there, but it may be the only one.
         writeStr("extern const QQmlPrivate::AOTCompiledFunction aotBuiltFunctions[];\n"
-                 "extern const QQmlPrivate::AOTCompiledFunction aotBuiltFunctions[] = { { 0, QMetaType::fromType<void>(), {}, nullptr } };");
+                 "extern const QQmlPrivate::AOTCompiledFunction aotBuiltFunctions[] = { { 0, QMetaType::fromType<void>(), {}, nullptr } };\n");
     } else {
-        writeStr(wrapCallCode);
         writeStr("extern const QQmlPrivate::AOTCompiledFunction aotBuiltFunctions[];\n"
                  "extern const QQmlPrivate::AOTCompiledFunction aotBuiltFunctions[] = {\n");
 
-        QString footer = QStringLiteral("});}\n");
+        QString footer = QStringLiteral("}\n");
 
         for (QQmlJSAotFunctionMap::ConstIterator func = aotFunctions.constBegin(),
              end = aotFunctions.constEnd();