--- /dev/null	2017-11-16 08:17:56.803999947 +0100
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/gc/g1/G1BarrierSet.java	2019-03-09 03:57:54.565431368 +0100
@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, Red Hat Inc. 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.hotspot.gc.g1;
+
+import org.graalvm.compiler.debug.GraalError;
+import org.graalvm.compiler.hotspot.gc.shared.BarrierSet;
+import org.graalvm.compiler.nodes.StructuredGraph;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.extended.ArrayRangeWrite;
+import org.graalvm.compiler.nodes.java.AbstractCompareAndSwapNode;
+import org.graalvm.compiler.nodes.java.LoweredAtomicReadAndWriteNode;
+import org.graalvm.compiler.nodes.memory.FixedAccessNode;
+import org.graalvm.compiler.nodes.memory.HeapAccess;
+import org.graalvm.compiler.nodes.memory.ReadNode;
+import org.graalvm.compiler.nodes.memory.WriteNode;
+import org.graalvm.compiler.nodes.memory.address.AddressNode;
+import org.graalvm.compiler.nodes.type.StampTool;
+
+public class G1BarrierSet extends BarrierSet {
+
+    @Override
+    public void addReadNodeBarriers(ReadNode node, StructuredGraph graph) {
+        if (node.getBarrierType() != HeapAccess.BarrierType.NONE) {
+            assert (node.getBarrierType() == HeapAccess.BarrierType.PRECISE);
+            G1ReferentFieldReadBarrier barrier = graph.add(new G1ReferentFieldReadBarrier(node.getAddress(), node, false));
+            graph.addAfterFixed(node, barrier);
+        }
+    }
+
+    @Override
+    public void addWriteNodeBarriers(WriteNode node, StructuredGraph graph) {
+        HeapAccess.BarrierType barrierType = node.getBarrierType();
+        switch (barrierType) {
+            case NONE:
+                // nothing to do
+                break;
+            case IMPRECISE:
+            case PRECISE:
+                boolean precise = barrierType == HeapAccess.BarrierType.PRECISE;
+                if (!node.getLocationIdentity().isInit()) {
+                    // The pre barrier does nothing if the value being read is null, so it can
+                    // be explicitly skipped when this is an initializing store.
+                    addG1PreWriteBarrier(node, node.getAddress(), null, true, node.getNullCheck(), graph);
+                }
+                addG1PostWriteBarrier(node, node.getAddress(), node.value(), precise, graph);
+                break;
+            default:
+                throw new GraalError("unexpected barrier type: " + barrierType);
+        }
+    }
+
+    @Override
+    public void addAtomicReadWriteNodeBarriers(LoweredAtomicReadAndWriteNode node, StructuredGraph graph) {
+        HeapAccess.BarrierType barrierType = node.getBarrierType();
+        switch (barrierType) {
+            case NONE:
+                // nothing to do
+                break;
+            case IMPRECISE:
+            case PRECISE:
+                boolean precise = barrierType == HeapAccess.BarrierType.PRECISE;
+                addG1PreWriteBarrier(node, node.getAddress(), null, true, node.getNullCheck(), graph);
+                addG1PostWriteBarrier(node, node.getAddress(), node.getNewValue(), precise, graph);
+                break;
+            default:
+                throw new GraalError("unexpected barrier type: " + barrierType);
+        }
+    }
+
+    @Override
+    public void addCASBarriers(AbstractCompareAndSwapNode node, StructuredGraph graph) {
+        HeapAccess.BarrierType barrierType = node.getBarrierType();
+        switch (barrierType) {
+            case NONE:
+                // nothing to do
+                break;
+            case IMPRECISE:
+            case PRECISE:
+                boolean precise = barrierType == HeapAccess.BarrierType.PRECISE;
+                addG1PreWriteBarrier(node, node.getAddress(), node.getExpectedValue(), false, false, graph);
+                addG1PostWriteBarrier(node, node.getAddress(), node.getNewValue(), precise, graph);
+                break;
+            default:
+                throw new GraalError("unexpected barrier type: " + barrierType);
+        }
+    }
+
+    @Override
+    public void addArrayRangeBarriers(ArrayRangeWrite write, StructuredGraph graph) {
+        if (!write.isInitialization()) {
+            // The pre barrier does nothing if the value being read is null, so it can
+            // be explicitly skipped when this is an initializing store.
+            G1ArrayRangePreWriteBarrier g1ArrayRangePreWriteBarrier = graph.add(new G1ArrayRangePreWriteBarrier(write.getAddress(), write.getLength(), write.getElementStride()));
+            graph.addBeforeFixed(write.asNode(), g1ArrayRangePreWriteBarrier);
+        }
+        G1ArrayRangePostWriteBarrier g1ArrayRangePostWriteBarrier = graph.add(new G1ArrayRangePostWriteBarrier(write.getAddress(), write.getLength(), write.getElementStride()));
+        graph.addAfterFixed(write.asNode(), g1ArrayRangePostWriteBarrier);
+    }
+
+    private static void addG1PreWriteBarrier(FixedAccessNode node, AddressNode address, ValueNode value, boolean doLoad, boolean nullCheck, StructuredGraph graph) {
+        G1PreWriteBarrier preBarrier = graph.add(new G1PreWriteBarrier(address, value, doLoad, nullCheck));
+        preBarrier.setStateBefore(node.stateBefore());
+        node.setNullCheck(false);
+        node.setStateBefore(null);
+        graph.addBeforeFixed(node, preBarrier);
+    }
+
+    private static void addG1PostWriteBarrier(FixedAccessNode node, AddressNode address, ValueNode value, boolean precise, StructuredGraph graph) {
+        final boolean alwaysNull = StampTool.isPointerAlwaysNull(value);
+        graph.addAfterFixed(node, graph.add(new G1PostWriteBarrier(address, value, precise, alwaysNull)));
+    }
+}