1 files changed, 74 insertions, 0 deletions
diff --git a/src/qml/common/qv4alloca_p.h b/src/qml/common/qv4alloca_p.h
new file mode 100644
index 0000000000..c1d1e6e87d
--- /dev/null
+++ b/src/qml/common/qv4alloca_p.h
@@ -0,0 +1,74 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QV4_ALLOCA_H
+#define QV4_ALLOCA_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/private/qglobal_p.h>
+
+#if QT_CONFIG(alloca_h)
+#  include <alloca.h>
+#elif QT_CONFIG(alloca_malloc_h)
+#  include <malloc.h>
+// This does not matter unless compiling in strict standard mode.
+#  ifdef Q_CC_MSVC
+#    define alloca _alloca
+#  endif
+#else
+#  include <stdlib.h>
+#endif
+
+// Define Q_ALLOCA_VAR macro to be used instead of #ifdeffing
+// the occurrences of alloca() in case it's not supported.
+// Q_ALLOCA_DECLARE and Q_ALLOCA_ASSIGN macros separate
+// memory allocation from the declaration and RAII.
+#define Q_ALLOCA_VAR(type, name, size) \
+    Q_ALLOCA_DECLARE(type, name); \
+    Q_ALLOCA_ASSIGN(type, name, size)
+
+#if QT_CONFIG(alloca)
+
+#define Q_ALLOCA_DECLARE(type, name) \
+    type *name = 0
+
+#define Q_ALLOCA_ASSIGN(type, name, size) \
+    name = static_cast<type*>(alloca(size))
+
+#else
+QT_BEGIN_NAMESPACE
+class Qt_AllocaWrapper
+{
+public:
+    Qt_AllocaWrapper() { m_data = 0; }
+    ~Qt_AllocaWrapper() { free(m_data); }
+    void *data() { return m_data; }
+    void allocate(int size) { m_data = malloc(size); memset(m_data, 0, size); }
+private:
+    void *m_data;
+};
+QT_END_NAMESPACE
+
+#define Q_ALLOCA_DECLARE(type, name) \
+    Qt_AllocaWrapper _qt_alloca_##name; \
+    type *name = nullptr
+
+#define Q_ALLOCA_ASSIGN(type, name, size) \
+    do { \
+        _qt_alloca_##name.allocate(size); \
+        name = static_cast<type*>(_qt_alloca_##name.data()); \
+    } while (false)
+
+#endif
+
+#endif