Partial Atomics support

Implement support for basic atomic operations on
SharedArrayBuffers.

Half of the methods still need a proper implementation.

Change-Id: Ia88da358e0c2ae6d28e9bcc1feb8980b6f51a812
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 190 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4atomics.cpp b/src/qml/jsruntime/qv4atomics.cpp
new file mode 100644
index 0000000000..21813c0667
--- /dev/null
+++ b/src/qml/jsruntime/qv4atomics.cpp
@@ -0,0 +1,190 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** 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
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** 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
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#include "qv4arraybuffer_p.h"
+#include "qv4typedarray_p.h"
+#include "qv4atomics_p.h"
+#include "qv4symbol_p.h"
+
+using namespace QV4;
+
+DEFINE_OBJECT_VTABLE(Atomics);
+
+void Heap::Atomics::init()
+{
+    Object::init();
+    Scope scope(internalClass->engine);
+    ScopedObject m(scope, this);
+
+    m->defineDefaultProperty(QStringLiteral("add"), QV4::Atomics::method_add, 3);
+    m->defineDefaultProperty(QStringLiteral("and"), QV4::Atomics::method_and, 3);
+    m->defineDefaultProperty(QStringLiteral("compareExchange"), QV4::Atomics::method_compareExchange, 4);
+    m->defineDefaultProperty(QStringLiteral("exchange"), QV4::Atomics::method_exchange, 3);
+    m->defineDefaultProperty(QStringLiteral("isLockFree"), QV4::Atomics::method_isLockFree, 1);
+    m->defineDefaultProperty(QStringLiteral("load"), QV4::Atomics::method_load, 2);
+    m->defineDefaultProperty(QStringLiteral("or"), QV4::Atomics::method_or, 3);
+    m->defineDefaultProperty(QStringLiteral("store"), QV4::Atomics::method_store, 3);
+    m->defineDefaultProperty(QStringLiteral("sub"), QV4::Atomics::method_sub, 3);
+    m->defineDefaultProperty(QStringLiteral("wait"), QV4::Atomics::method_wait, 4);
+    m->defineDefaultProperty(QStringLiteral("wake"), QV4::Atomics::method_wake, 3);
+    m->defineDefaultProperty(QStringLiteral("xor"), QV4::Atomics::method_xor, 3);
+
+    ScopedString name(scope, scope.engine->newString(QStringLiteral("Atomics")));
+    m->defineReadonlyConfigurableProperty(scope.engine->symbol_toStringTag(), name);
+}
+
+static SharedArrayBuffer *validateSharedIntegerTypedArray(Scope &scope, const Value &typedArray, bool onlyInt32 = false)
+{
+    const TypedArray *a = typedArray.as<TypedArray>();
+    if (!a) {
+        scope.engine->throwTypeError();
+        return nullptr;
+    }
+
+    TypedArrayType t(a->arrayType());
+    if (!a->d()->type->atomicLoad || (onlyInt32 && t != TypedArrayType::Int32Array)) {
+        scope.engine->throwTypeError();
+        return nullptr;
+    }
+
+    Scoped<SharedArrayBuffer> buffer(scope, a->d()->buffer);
+    if (!buffer->isSharedArrayBuffer()) {
+        scope.engine->throwTypeError();
+        return nullptr;
+    }
+    Q_ASSERT(!buffer->isDetachedBuffer());
+    return buffer;
+}
+
+static int validateAtomicAccess(Scope &scope, const TypedArray &typedArray, const Value &index)
+{
+    const TypedArray &a = static_cast<const TypedArray &>(typedArray);
+    qint64 idx = index.toIndex();
+    if (scope.hasException())
+        return -1;
+    if (idx < 0 || idx >= a.length()) {
+        scope.engine->throwRangeError(QStringLiteral("index out of range."));
+        return -1;
+    }
+    return static_cast<int>(idx);
+}
+
+ReturnedValue atomicReadModifyWrite(const FunctionObject *f, const Value *argv, int argc, AtomicModifyOps modify)
+{
+    Scope scope(f);
+    if (!argc)
+        return scope.engine->throwTypeError();
+
+    SharedArrayBuffer *buffer = validateSharedIntegerTypedArray(scope, argv[0]);
+    if (!buffer)
+        return Encode::undefined();
+    const TypedArray &a = static_cast<const TypedArray &>(argv[0]);
+    int index = validateAtomicAccess(scope, a, argc > 1 ? argv[1] : Primitive::undefinedValue());
+    if (index < 0)
+        return Encode::undefined();
+
+    Value v = Primitive::fromReturnedValue((argc > 2 ? argv[2] : Primitive::undefinedValue()).convertedToNumber());
+    if (scope.hasException())
+        return Encode::undefined();
+
+    int bytesPerElement = a.d()->type->bytesPerElement;
+    int byteOffset = a.d()->byteOffset + index * bytesPerElement;
+
+    return a.d()->type->atomicModifyOps[modify](buffer->data() + byteOffset, v);
+}
+
+ReturnedValue Atomics::method_add(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicAdd);
+}
+
+ReturnedValue Atomics::method_and(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicAnd);
+}
+
+ReturnedValue Atomics::method_compareExchange(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_exchange(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicExchange);
+}
+
+ReturnedValue Atomics::method_isLockFree(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_load(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_or(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicOr);
+}
+
+ReturnedValue Atomics::method_store(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_sub(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicSub);
+}
+
+ReturnedValue Atomics::method_wait(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_wake(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+ReturnedValue Atomics::method_xor(const FunctionObject *f, const Value *, const Value *argv, int argc)
+{
+    return atomicReadModifyWrite(f, argv, argc, AtomicXor);
+
+}