Add initial basic support for ES6 modules

The entry point from the parsing perspective into modules is not
QV4::Script but QV4::ExecutionEngine::compileModule.

For convenience, the ESModule AST node gets a body, which is the
statement list connected between the ModuleItemList items that are not
import/export declarations.

The QV4::Module allocates a call context where the exported variables
are stored as named locals. This will also become the module namespace
object.

The imports in turn is an array of value pointers that point into the
locals array of the context of the imported modules.

The default module loading in ExecutionEngine assumes the accessibility
of module urls via QFile (so local file system or resource). This is
what qmljs also uses and QJSEngine as well via public API in the future.

The test runner compiles the modules manually and injects them, because
they need to be compiled together with the test harness code.

The QML type loader will the mechanism for injection in the future for
module imports from .qml files.

Change-Id: I93be9cfe54c651fdbd08c5e1d22d58f47284e54f
Reviewed-by: Qt CI Bot <[email protected]>
Reviewed-by: Lars Knoll <[email protected]>

1 files changed, 69 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4module.cpp b/src/qml/jsruntime/qv4module.cpp
new file mode 100644
index 0000000000..ed7df459b6
--- /dev/null
+++ b/src/qml/jsruntime/qv4module.cpp
@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
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+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
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+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
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+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include "qv4module_p.h"
+
+#include <private/qv4mm_p.h>
+#include <private/qv4vme_moth_p.h>
+#include <private/qv4context_p.h>
+
+using namespace QV4;
+
+DEFINE_OBJECT_VTABLE(Module);
+
+void Heap::Module::init(ExecutionEngine *engine, CompiledData::CompilationUnit *moduleUnit)
+{
+    Object::init();
+
+    // This is a back pointer and there is no need to call addref() on the unit, because the unit
+    // owns this object instead.
+    unit = moduleUnit;
+
+    Function *moduleFunction = unit->runtimeFunctions[unit->unitData()->indexOfRootFunction];
+
+    const uint locals = moduleFunction->compiledFunction->nLocals;
+    const size_t requiredMemory = sizeof(QV4::CallContext::Data) - sizeof(Value) + sizeof(Value) * locals;
+    scope.set(engine, engine->memoryManager->allocManaged<QV4::CallContext>(requiredMemory, moduleFunction->internalClass));
+    scope->init();
+    scope->outer.set(engine, engine->rootContext()->d());
+    scope->locals.size = locals;
+    scope->locals.alloc = locals;
+    scope->nArgs = 0;
+}