--- /dev/null	2017-11-16 08:17:56.803999947 +0100
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.serviceprovider/src/org/graalvm/compiler/serviceprovider/SpeculationReasonGroup.java	2019-03-12 08:10:55.140088323 +0100
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+
+
+package org.graalvm.compiler.serviceprovider;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import jdk.vm.ci.code.BytecodePosition;
+import jdk.vm.ci.meta.ResolvedJavaMethod;
+import jdk.vm.ci.meta.ResolvedJavaType;
+import jdk.vm.ci.meta.SpeculationLog.SpeculationReason;
+
+/**
+ * Facility for creating speculation reasons partitioned in groups.
+ */
+public final class SpeculationReasonGroup {
+
+    private final int id;
+    private final String name;
+    private final Class<?>[] signature;
+
+    private static final AtomicInteger nextId = new AtomicInteger(1);
+
+    /**
+     * Creates speculation group whose context will always match {@code signature}.
+     */
+    public SpeculationReasonGroup(String name, Class<?>... signature) {
+        this.id = nextId.get();
+        this.name = name;
+        this.signature = signature;
+        for (Class<?> c : signature) {
+            if (!isOfSupportedType(c)) {
+                throw new IllegalArgumentException("Unsupported speculation context type: " + c.getName());
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%s{id:%d, sig=%s}", name, id, Arrays.toString(signature));
+    }
+
+    /**
+     * Creates a speculation reason described by this group.
+     *
+     * @param context the components of the reason instance being created
+     */
+    public SpeculationReason createSpeculationReason(Object... context) {
+        assert checkSignature(context);
+        return GraalServices.createSpeculationReason(id, name, context);
+    }
+
+    private static final Set<Class<?>> SUPPORTED_EXACT_TYPES = new HashSet<>(Arrays.asList(
+                    String.class,
+                    int.class,
+                    long.class,
+                    float.class,
+                    double.class,
+                    BytecodePosition.class));
+
+    private static boolean isOfSupportedType(Class<?> c) {
+        if (SUPPORTED_EXACT_TYPES.contains(c)) {
+            return true;
+        }
+        if (Enum.class.isAssignableFrom(c)) {
+            // Trust the ordinal of an Enum to be unique
+            return true;
+        }
+        if (SpeculationContextObject.class.isAssignableFrom(c)) {
+            return true;
+        }
+        if (ResolvedJavaMethod.class.isAssignableFrom(c) || ResolvedJavaType.class.isAssignableFrom(c)) {
+            // Only the JVMCI implementation specific concrete subclasses
+            // of these types will be accepted but we cannot test for that
+            // here since we are in JVMCI implementation agnostic code.
+            return true;
+        }
+        return false;
+    }
+
+    static Class<?> toBox(Class<?> c) {
+        if (c == int.class) {
+            return Integer.class;
+        }
+        if (c == long.class) {
+            return Long.class;
+        }
+        if (c == float.class) {
+            return Float.class;
+        }
+        if (c == double.class) {
+            return Double.class;
+        }
+        return c;
+    }
+
+    private boolean checkSignature(Object[] context) {
+        assert signature.length == context.length : name + ": Incorrect number of context arguments. Expected " + signature.length + ", got " + context.length;
+        for (int i = 0; i < context.length; i++) {
+            Object o = context[i];
+            Class<?> c = signature[i];
+            if (o != null) {
+                if (c == ResolvedJavaMethod.class || c == ResolvedJavaType.class || SpeculationContextObject.class.isAssignableFrom(c)) {
+                    c.cast(o);
+                } else {
+                    Class<?> oClass = o.getClass();
+                    assert toBox(c) == oClass : name + ": Context argument " + i + " is not a " + c.getName() + " but a " + oClass.getName();
+                }
+            } else {
+                if (c.isPrimitive() || Enum.class.isAssignableFrom(c)) {
+                    throw new AssertionError(name + ": Cannot pass null for argument " + i);
+                }
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Denotes part of a {@linkplain SpeculationReasonGroup#createSpeculationReason(Object...)
+     * reason} that can have its attributes {@linkplain #accept(Visitor) visited}.
+     */
+    public interface SpeculationContextObject {
+        void accept(Visitor v);
+
+        public interface Visitor {
+            void visitBoolean(boolean v);
+
+            void visitByte(byte v);
+
+            void visitChar(char v);
+
+            void visitShort(short v);
+
+            void visitInt(int v);
+
+            void visitLong(long v);
+
+            void visitFloat(float v);
+
+            void visitDouble(double v);
+
+            void visitObject(Object v);
+        }
+    }
+}