diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/runtime/commandLineFlagConstraintList.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/commandLineFlagConstraintList.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2015, 2016, 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_RUNTIME_COMMANDLINEFLAGCONSTRAINTLIST_HPP
+#define SHARE_VM_RUNTIME_COMMANDLINEFLAGCONSTRAINTLIST_HPP
+
+#include "runtime/globals.hpp"
+#include "utilities/growableArray.hpp"
+
+/*
+ * Here we have a mechanism for extracting constraints (as custom functions) for flags,
+ * which otherwise can not be expressed via simple range check, specified in flag macro tables.
+ *
+ * An example of a constraint is "flag1 < flag2" where both flag1 and flag2 can change.
+ *
+ * See runtime "runtime/commandLineFlagConstraintsCompiler.hpp",
+ * "runtime/commandLineFlagConstraintsGC.hpp" and
+ * "runtime/commandLineFlagConstraintsRuntime.hpp" for the functions themselves.
+ */
+
+typedef Flag::Error (*CommandLineFlagConstraintFunc_bool)(bool value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_int)(int value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_intx)(intx value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_uint)(uint value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_uintx)(uintx value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_uint64_t)(uint64_t value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_size_t)(size_t value, bool verbose);
+typedef Flag::Error (*CommandLineFlagConstraintFunc_double)(double value, bool verbose);
+
+class CommandLineFlagConstraint : public CHeapObj<mtArguments> {
+public:
+  // During VM initialization, constraint validation will be done order of ConstraintType.
+  enum ConstraintType {
+    // Will be validated during argument processing (Arguments::parse_argument).
+    AtParse         = 0,
+    // Will be validated inside Threads::create_vm(), right after Arguments::apply_ergo().
+    AfterErgo       = 1,
+    // Will be validated inside universe_init(), right after Metaspace::global_initialize().
+    AfterMemoryInit = 2
+  };
+
+private:
+  const char* _name;
+  ConstraintType _validate_type;
+
+public:
+  // the "name" argument must be a string literal
+  CommandLineFlagConstraint(const char* name, ConstraintType type) { _name=name; _validate_type=type; };
+  ~CommandLineFlagConstraint() {};
+  const char* name() const { return _name; }
+  ConstraintType type() const { return _validate_type; }
+  virtual Flag::Error apply(bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_bool(bool value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_int(int value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_intx(intx value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_uint(uint value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_uintx(uintx value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_uint64_t(uint64_t value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_size_t(size_t value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+  virtual Flag::Error apply_double(double value, bool verbose = true) { ShouldNotReachHere(); return Flag::ERR_OTHER; };
+};
+
+class CommandLineFlagConstraintList : public AllStatic {
+private:
+  static GrowableArray<CommandLineFlagConstraint*>* _constraints;
+  // Latest constraint validation type.
+  static CommandLineFlagConstraint::ConstraintType _validating_type;
+public:
+  static void init();
+  static int length() { return (_constraints != NULL) ? _constraints->length() : 0; }
+  static CommandLineFlagConstraint* at(int i) { return (_constraints != NULL) ? _constraints->at(i) : NULL; }
+  static CommandLineFlagConstraint* find(const char* name);
+  static CommandLineFlagConstraint* find_if_needs_check(const char* name);
+  static void add(CommandLineFlagConstraint* constraint) { _constraints->append(constraint); }
+  // True if 'AfterErgo' or later constraint functions are validated.
+  static bool validated_after_ergo() { return _validating_type >= CommandLineFlagConstraint::AfterErgo; };
+  static bool check_constraints(CommandLineFlagConstraint::ConstraintType type);
+};
+
+#endif /* SHARE_VM_RUNTIME_COMMANDLINEFLAGCONSTRAINTLIST_HPP */