Support top level generator functions

Extends grammar to support generator functions in QML components and
adjusts codegen accordingly

The corresponding test case must be blacklisted in tst_qmlmin, as qmlmin
cannot handle yield statements

Fixes: QTBUG-77096
Change-Id: I47d45dd56289cdf073b41932a585259d3052de04
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 66 insertions, 7 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index aab3f8e9d6..171dc641d3 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -908,7 +908,7 @@ bool IRBuilder::visit(QQmlJS::AST::UiPublicMember *node)
 
 bool IRBuilder::visit(QQmlJS::AST::UiSourceElement *node)
 {
-    if (QQmlJS::AST::FunctionDeclaration *funDecl = QQmlJS::AST::cast<QQmlJS::AST::FunctionDeclaration *>(node->sourceElement)) {
+    if (QQmlJS::AST::FunctionExpression *funDecl = node->sourceElement->asFunctionDefinition()) {
         CompiledFunctionOrExpression *foe = New<CompiledFunctionOrExpression>();
         foe->node = funDecl;
         foe->parentNode = funDecl;
@@ -1770,7 +1770,7 @@ QVector<int> JSCodeGen::generateJSCodeForFunctionsAndBindings(const QList<Compil
     for (const CompiledFunctionOrExpression &f : functions) {
         Q_ASSERT(f.node != document->program);
         Q_ASSERT(f.parentNode && f.parentNode != document->program);
-        QQmlJS::AST::FunctionDeclaration *function = QQmlJS::AST::cast<QQmlJS::AST::FunctionDeclaration*>(f.node);
+        auto function = f.node->asFunctionDefinition();
 
         if (function) {
             scan.enterQmlFunction(function);
@@ -1794,7 +1794,7 @@ QVector<int> JSCodeGen::generateJSCodeForFunctionsAndBindings(const QList<Compil
         QQmlJS::AST::Node *node = qmlFunction.node;
         Q_ASSERT(node != document->program);
 
-        QQmlJS::AST::FunctionDeclaration *function = QQmlJS::AST::cast<QQmlJS::AST::FunctionDeclaration*>(node);
+        QQmlJS::AST::FunctionExpression *function = node->asFunctionDefinition();
 
         QString name;
         if (function)
diff --git a/src/qml/compiler/qv4compilerscanfunctions_p.h b/src/qml/compiler/qv4compilerscanfunctions_p.h
index f67db030a2..2de80eac44 100644
--- a/src/qml/compiler/qv4compilerscanfunctions_p.h
+++ b/src/qml/compiler/qv4compilerscanfunctions_p.h
@@ -88,7 +88,7 @@ public:
                           const QString &name);
     void leaveEnvironment();
 
-    void enterQmlFunction(QQmlJS::AST::FunctionDeclaration *ast)
+    void enterQmlFunction(QQmlJS::AST::FunctionExpression *ast)
     { enterFunction(ast, false); }
 
 protected:
diff --git a/src/qml/parser/qqmljs.g b/src/qml/parser/qqmljs.g
index 82b040232a..6c9760e472 100644
--- a/src/qml/parser/qqmljs.g
+++ b/src/qml/parser/qqmljs.g
@@ -1396,6 +1396,14 @@ UiObjectMember: FunctionDeclarationWithTypes;
     } break;
 ./
 
+UiObjectMember: GeneratorExpression;
+/.
+    case $rule_number: {
+        auto node = new (pool) AST::UiSourceElement(sym(1).Node);
+        sym(1).Node = node;
+    } break;
+./
+
 UiObjectMember: VariableStatement;
 /.
     case $rule_number: {
diff --git a/src/qml/parser/qqmljsast_p.h b/src/qml/parser/qqmljsast_p.h
index 1502298d14..39194068bf 100644
--- a/src/qml/parser/qqmljsast_p.h
+++ b/src/qml/parser/qqmljsast_p.h
@@ -3351,7 +3351,7 @@ public:
 
     SourceLocation firstSourceLocation() const override
     {
-      if (FunctionDeclaration *funDecl = cast<FunctionDeclaration *>(sourceElement))
+      if (FunctionExpression *funDecl = sourceElement->asFunctionDefinition())
         return funDecl->firstSourceLocation();
       else if (VariableStatement *varStmt = cast<VariableStatement *>(sourceElement))
         return varStmt->firstSourceLocation();
@@ -3361,7 +3361,7 @@ public:
 
     SourceLocation lastSourceLocation() const override
     {
-      if (FunctionDeclaration *funDecl = cast<FunctionDeclaration *>(sourceElement))
+      if (FunctionExpression *funDecl = sourceElement->asFunctionDefinition())
         return funDecl->lastSourceLocation();
       else if (VariableStatement *varStmt = cast<VariableStatement *>(sourceElement))
         return varStmt->lastSourceLocation();
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index d5681b3449..f89608cd5d 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -57,6 +57,7 @@
 #include <private/qqmldebugserviceinterfaces_p.h>
 #include <private/qqmlscriptdata_p.h>
 #include <private/qjsvalue_p.h>
+#include <private/qv4generatorobject_p.h>
 
 #include <qtqml_tracepoints_p.h>
 
@@ -1135,7 +1136,10 @@ void QQmlObjectCreator::setupFunctions()
         if (!property->isVMEFunction())
             continue;
 
-        function = QV4::FunctionObject::createScriptFunction(qmlContext, runtimeFunction);
+        if (runtimeFunction->isGenerator())
+            function = QV4::GeneratorFunction::create(qmlContext, runtimeFunction);
+        else
+            function = QV4::FunctionObject::createScriptFunction(qmlContext, runtimeFunction);
         _vmeMetaObject->setVmeMethod(property->coreIndex(), function);
     }
 }
diff --git a/tests/auto/qml/qmlmin/tst_qmlmin.cpp b/tests/auto/qml/qmlmin/tst_qmlmin.cpp
index 696ec66246..cae833cd60 100644
--- a/tests/auto/qml/qmlmin/tst_qmlmin.cpp
+++ b/tests/auto/qml/qmlmin/tst_qmlmin.cpp
@@ -130,6 +130,8 @@ void tst_qmlmin::initTestCase()
     invalidFiles << "tests/auto/qml/qjsengine/script/com/trolltech/syntaxerror/__init__.js";
     invalidFiles << "tests/auto/qml/debugger/qqmlpreview/data/broken.qml";
     invalidFiles << "tests/auto/qml/qqmllanguage/data/fuzzed.2.qml";
+    // generatorFunction.qml is not invalid per se, but the minifier cannot handle yield statements
+    invalidFiles << "tests/auto/qml/qqmlecmascript/data/generatorFunction.qml";
 #endif
 }
 
diff --git a/tests/auto/qml/qqmlecmascript/data/generatorFunction.qml b/tests/auto/qml/qqmlecmascript/data/generatorFunction.qml
new file mode 100644
index 0000000000..66bb642f34
--- /dev/null
+++ b/tests/auto/qml/qqmlecmascript/data/generatorFunction.qml
@@ -0,0 +1,22 @@
+import QtQml 2.12
+
+QtObject {
+    id: root
+    property bool test1: false;
+    property bool test2: false;
+    property bool test3: false;
+    property bool done: false;
+    function *gen() {
+        yield 1
+        yield 2
+        yield 3
+    }
+
+    Component.onCompleted: {
+        let it = root.gen();
+        root.test1 = (it.next().value == 1);
+        root.test2 = (it.next().value == 2);
+        root.test3 = (it.next().value == 3);
+        root.done = it.next().done;
+    }
+}
diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index 00105c4225..b44fe9766c 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -233,6 +233,7 @@ private slots:
     void functionAssignment_afterBinding();
     void eval();
     void function();
+    void topLevelGeneratorFunction();
     void qtbug_10696();
     void qtbug_11606();
     void qtbug_11600();
@@ -6348,6 +6349,28 @@ void tst_qqmlecmascript::function()
     delete o;
 }
 
+// QTBUG-77096
+void tst_qqmlecmascript::topLevelGeneratorFunction()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("generatorFunction.qml"));
+
+    QScopedPointer<QObject> o {component.create()};
+    QVERIFY(o != nullptr);
+
+    // check that generator works correctly in QML
+    QCOMPARE(o->property("test1").toBool(), true);
+    QCOMPARE(o->property("test2").toBool(), true);
+    QCOMPARE(o->property("test3").toBool(), true);
+    QCOMPARE(o->property("done").toBool(), true);
+
+    // check that generator is accessible from C++
+    QVariant returnedValue;
+    QMetaObject::invokeMethod(o.get(), "gen", Q_RETURN_ARG(QVariant, returnedValue));
+    auto it = returnedValue.value<QJSValue>();
+    QCOMPARE(it.property("next").callWithInstance(it).property("value").toInt(), 1);
+}
+
 // Test the "Qt.include" method
 void tst_qqmlecmascript::include()
 {