--- /dev/null	2017-03-07 11:44:12.271151064 +0100
+++ new/src/share/vm/metaprogramming/integerTypes.hpp	2017-07-27 17:46:47.227146559 +0200
@@ -0,0 +1,293 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_METAPROGRAMMING_INTEGERTYPES_HPP
+#define SHARE_VM_METAPROGRAMMING_INTEGERTYPES_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/debug.hpp"
+#include "metaprogramming/decay.hpp"
+#include "metaprogramming/integralConstant.hpp"
+#include "metaprogramming/isFloatingPoint.hpp"
+#include "metaprogramming/isPointer.hpp"
+#include "metaprogramming/isSigned.hpp"
+#include "metaprogramming/isIntegral.hpp"
+
+class IntegerTypes : public AllStatic {
+public:
+  // Metafunction returning a canonical type of the same size and signed as T.
+  // T must be an integral type. The canonical types are guaranteed to be
+  // the [u]intN_t types from stdint.h
+  template<typename T> struct Canonical;
+
+  // Metafunction returning the canonical signed integral type of the
+  // given size.
+  template<size_t byte_size> struct SignedTypeOfSize;
+
+  // Metafunction returning the canonical unsigned integral type of
+  // the given size.
+  template<size_t byte_size> struct UnsignedTypeOfSize;
+
+  // Metafunction returning the canonical signed integral type of the
+  // same size as T.  T must be an integral, floating point, or
+  // pointer type.
+  template<typename T> struct Signed;
+
+  // Metafunction returning the canonical unsigned integral type of
+  // the same size as T.  T must be an integral, floating point, or
+  // pointer type.
+  template<typename T> struct Unsigned;
+
+  // Return a signed integral value with the same representation as x.
+  // T must be an integral, floating point, or pointer type.
+  // If T is a signed type, then x == cast_to_signed(x).
+  template<typename T>
+  static typename Signed<T>::type cast_to_signed(T x);
+
+  // Return an unsigned integral value with the same representation as x.
+  // T must be an integral, floating point, or pointer type.
+  // If T is an unsigned type, then x == cast_to_unsigned(x).
+  template<typename T>
+  static typename Unsigned<T>::type cast_to_unsigned(T x);
+
+  // Return a value with the same representation as x.
+  // T must be an integral, floating point, or pointer type.
+  // U must be an integral type.  T and U must be of the same size.
+  // If T and U are both signed or both unsigned integral types, then
+  // x == cast<T>(x).
+  template<typename T, typename U>
+  static T cast(U x);
+
+private:
+  template<typename T, bool is_signed = IsSigned<T>::value>
+  struct CanonicalImpl;
+
+  template<typename T, bool is_pointer = IsPointer<T>::value, bool is_float = IsFloatingPoint<T>::value>
+  struct TypeForSize;
+
+  template<typename T, typename U, bool from_pointer = IsPointer<U>::value, bool from_float = IsFloatingPoint<U>::value>
+  struct CastTo;
+
+  template<typename T,
+           typename U,
+           bool same_size = sizeof(T) == sizeof(U),
+           bool to_pointer = IsPointer<T>::value,
+           bool to_float = IsFloatingPoint<T>::value>
+  struct Cast;
+
+  template<typename T, typename U> static T cast_integral(U x);
+  template<typename T, typename U> static T cast_floating_point(U x);
+};
+
+// Convert between different integral types of the same size.
+// See C++03 3.10/15 for discussion of reinterpret_cast to a reference
+// as a means for converting integral types while keeping the representation.
+template<typename T, typename U>
+inline T IntegerTypes::cast_integral(U x) {
+  STATIC_ASSERT(sizeof(T) == sizeof(U));
+  return reinterpret_cast<T&>(x);
+}
+
+// Convert between an integral type and a floating point type of the
+// same size.  The only truly correct way to do this is with memcpy.
+// Both the union trick and type punning via casts are undefined
+// behavior. gcc generates exactly the same code for all three methods,
+// except where the UB of type punning causes it to go off into the weeds.
+// (gcc explicitly supports the union trick.)  Other compilers may vary.
+// In particular, not all compilers do a good job with the memcpy.
+template<typename T, typename U>
+inline T IntegerTypes::cast_floating_point(U x) {
+  STATIC_ASSERT(sizeof(T) == sizeof(U));
+  T result;
+  memcpy(&result, &x, sizeof(x));
+  return result;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// SignedTypeOfSize<size_t> and UnsignedTypeOfSize<size_t>
+
+#define DEFINE_CANONICAL_SIGNED_TYPE(T)                                 \
+  template<>                                                            \
+  struct IntegerTypes::SignedTypeOfSize<sizeof(T)> : public AllStatic { \
+    typedef T type;                                                     \
+  };
+
+#define DEFINE_CANONICAL_UNSIGNED_TYPE(T)                               \
+  template<>                                                            \
+  struct IntegerTypes::UnsignedTypeOfSize<sizeof(T)> : public AllStatic { \
+    typedef T type;                                                     \
+  };
+
+#define DEFINE_INTEGER_TYPES_OF_SIZE(NBITS)            \
+  DEFINE_CANONICAL_SIGNED_TYPE(int ## NBITS ## _t)     \
+  DEFINE_CANONICAL_UNSIGNED_TYPE(uint ## NBITS ## _t)
+
+DEFINE_INTEGER_TYPES_OF_SIZE(8)
+DEFINE_INTEGER_TYPES_OF_SIZE(16)
+DEFINE_INTEGER_TYPES_OF_SIZE(32)
+DEFINE_INTEGER_TYPES_OF_SIZE(64)
+
+#undef DEFINE_INTEGER_TYPES_OF_SIZE
+#undef DEFINE_CANONICAL_SIGNED_TYPE
+#undef DEFINE_CANONICAL_UNSIGNED_TYPE
+
+//////////////////////////////////////////////////////////////////////////////
+// Canonical<T>
+
+template<typename T>
+struct IntegerTypes::CanonicalImpl<T, true>
+  : public SignedTypeOfSize<sizeof(T)>
+{ };
+
+template<typename T>
+struct IntegerTypes::CanonicalImpl<T, false>
+  : public UnsignedTypeOfSize<sizeof(T)>
+{ };
+
+template<typename T>
+struct IntegerTypes::Canonical : public CanonicalImpl<T> {
+  STATIC_ASSERT((IsIntegral<T>::value));
+};
+
+//////////////////////////////////////////////////////////////////////////////
+// Signed<T> and Unsigned<T>
+
+// For other types, use the canonical type, ensuring T is integral.
+template<typename T>
+struct IntegerTypes::TypeForSize<T, false, false> : public Canonical<T> { };
+
+// For floating point types, use the type.
+template<typename T>
+struct IntegerTypes::TypeForSize<T, false, true> : public AllStatic {
+  typedef T type;
+};
+
+// For pointer types, use void*.
+template<typename T>
+struct IntegerTypes::TypeForSize<T, true, false> : public AllStatic {
+  typedef void* type;
+};
+
+template<typename T>
+struct IntegerTypes::Signed
+  : public SignedTypeOfSize<sizeof(typename TypeForSize<T>::type)>
+{ };
+
+template<typename T>
+struct IntegerTypes::Unsigned
+  : public UnsignedTypeOfSize<sizeof(typename TypeForSize<T>::type)>
+{ };
+
+//////////////////////////////////////////////////////////////////////////////
+// cast<T>(x)
+//
+// Cast from an integral type to an integral, floating point, or pointer type.
+// Cast<T, U, same_size, to_pointer, to_float>
+
+// Cast integral value to some different type of integral value.
+template<typename T, typename U>
+struct IntegerTypes::Cast<T, U, true, false, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const {
+    // Canonicalization verifies T is integral.
+    typedef typename Canonical<T>::type canonical_type;
+    return static_cast<T>(cast_integral<canonical_type>(x));
+  }
+};
+
+// Cast integral value to floating point.
+template<typename T, typename U>
+struct IntegerTypes::Cast<T, U, true, false, true> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const { return cast_floating_point<T>(x); }
+};
+
+// Cast integral value to pointer.
+template<typename T, typename U>
+struct IntegerTypes::Cast<T, U, true, true, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const { return reinterpret_cast<T>(x); }
+};
+
+// Same integral type is identity conversion.
+template<typename T>
+struct IntegerTypes::Cast<T, T, true, false, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(T x) const { return x; }
+};
+
+// Give an informative error if the sizes differ.
+template<typename T, typename U, bool to_pointer, bool to_float>
+struct IntegerTypes::Cast<T, U, false, to_pointer, to_float> VALUE_OBJ_CLASS_SPEC {
+  STATIC_ASSERT(sizeof(T) == sizeof(U));
+};
+
+template<typename T, typename U>
+inline T IntegerTypes::cast(U x) {
+  // Canonicalization verifies U is integral.
+  typedef typename Canonical<U>::type parameter_type;
+  return Cast<T, parameter_type>()(static_cast<parameter_type>(x));
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// cast_to_signed(x)
+// cast_to_unsigned(x)
+//
+// Cast from an integral, floating point, or pointer type to an integral type.
+
+// Cast integral to different integral.
+template<typename T, typename U>
+struct IntegerTypes::CastTo<T, U, false, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const { return cast_integral<T>(x); }
+};
+
+// Cast floating point to integral value.
+template<typename T, typename U>
+struct IntegerTypes::CastTo<T, U, false, true> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const { return cast_floating_point<T>(x); }
+};
+
+// Cast pointer to integral value.
+template<typename T, typename U>
+struct IntegerTypes::CastTo<T, U, true, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(U x) const { return reinterpret_cast<T>(x); }
+};
+
+// Identity conversion
+template<typename T>
+struct IntegerTypes::CastTo<T, T, false, false> VALUE_OBJ_CLASS_SPEC {
+  T operator()(T x) const { return x; }
+};
+
+template<typename T>
+inline typename IntegerTypes::Signed<T>::type
+IntegerTypes::cast_to_signed(T x) {
+  typedef typename Signed<T>::type result_type;
+  return CastTo<result_type, T>()(x);
+}
+
+template<typename T>
+inline typename IntegerTypes::Unsigned<T>::type
+IntegerTypes::cast_to_unsigned(T x) {
+  typedef typename Unsigned<T>::type result_type;
+  return CastTo<result_type, T>()(x);
+}
+
+#endif // SHARE_VM_METAPROGRAMMING_INTEGERTYPES_HPP