--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot.lir.test/src/org/graalvm/compiler/hotspot/lir/test/MitigateExceedingMaxOopMapStackOffsetTest.java	Thu Jun 27 03:33:44 2019 +0200
@@ -0,0 +1,163 @@
+/*
+ * 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.hotspot.lir.test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.graalvm.compiler.core.common.LIRKind;
+import org.graalvm.compiler.hotspot.HotSpotBackend;
+import org.graalvm.compiler.lir.VirtualStackSlot;
+import org.graalvm.compiler.lir.framemap.FrameMapBuilder;
+import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
+import org.graalvm.compiler.lir.jtt.LIRTest;
+import org.graalvm.compiler.lir.jtt.LIRTestSpecification;
+import org.graalvm.compiler.lir.stackslotalloc.LSStackSlotAllocator;
+import org.graalvm.compiler.nodes.SafepointNode;
+import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;
+import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderContext;
+import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin;
+import org.junit.Assume;
+import org.junit.Test;
+
+import jdk.vm.ci.meta.AllocatableValue;
+import jdk.vm.ci.meta.JavaConstant;
+import jdk.vm.ci.meta.ResolvedJavaMethod;
+
+/**
+ * Tests the mitigation against overflowing the max size limit for a HotSpot OopMap. The mitigation
+ * works by {@link LSStackSlotAllocator} placing reference typed stack slots at lower offsets.
+ */
+public class MitigateExceedingMaxOopMapStackOffsetTest extends LIRTest {
+
+    /**
+     * Allocate stacks slots and initializes those at an odd index with a reference constant and
+     * those at an even index with a primitive constant.
+     */
+    private static class WriteStackValues extends LIRTestSpecification {
+        private final JavaConstant objectConstant;
+        private final JavaConstant primitiveConstant;
+
+        WriteStackValues(JavaConstant objectConstant, JavaConstant primitiveConstant) {
+            this.objectConstant = objectConstant;
+            this.primitiveConstant = primitiveConstant;
+        }
+
+        @Override
+        public void generate(LIRGeneratorTool gen) {
+            FrameMapBuilder frameMapBuilder = gen.getResult().getFrameMapBuilder();
+            LIRKind objectLirKind = LIRKind.reference(gen.target().arch.getPlatformKind(objectConstant.getJavaKind()));
+            LIRKind primitiveLirKind = LIRKind.value(gen.target().arch.getPlatformKind(primitiveConstant.getJavaKind()));
+
+            int numSlots = numPrimitiveSlots + numReferenceSlots;
+            List<AllocatableValue> slotList = new ArrayList<>(numSlots);
+            // Place reference slots at top and bottom of virtual frame
+            // with primitive slots in the middle. This tests that slot
+            // partitioning works.
+            for (int i = 0; i < numReferenceSlots / 2; i++) {
+                AllocatableValue src = gen.emitLoadConstant(objectLirKind, objectConstant);
+                VirtualStackSlot slot = frameMapBuilder.allocateSpillSlot(objectLirKind);
+                slotList.add(slot);
+                gen.emitMove(slot, src);
+            }
+            for (int i = 0; i < numPrimitiveSlots; i++) {
+                AllocatableValue src = gen.emitLoadConstant(objectLirKind, primitiveConstant);
+                VirtualStackSlot slot = frameMapBuilder.allocateSpillSlot(primitiveLirKind);
+                slotList.add(slot);
+                gen.emitMove(slot, src);
+            }
+            for (int i = numReferenceSlots / 2; i < numReferenceSlots; i++) {
+                AllocatableValue src = gen.emitLoadConstant(objectLirKind, objectConstant);
+                VirtualStackSlot slot = frameMapBuilder.allocateSpillSlot(objectLirKind);
+                slotList.add(slot);
+                gen.emitMove(slot, src);
+            }
+            slots = slotList.toArray(new AllocatableValue[slotList.size()]);
+        }
+    }
+
+    /**
+     * Read stacks slots and move their content into a blackhole.
+     */
+    private static class ReadStackValues extends LIRTestSpecification {
+
+        ReadStackValues() {
+        }
+
+        @Override
+        public void generate(LIRGeneratorTool gen) {
+            for (int i = 0; i < slots.length; i++) {
+                gen.emitBlackhole(gen.emitMove(slots[i]));
+            }
+        }
+    }
+
+    @Override
+    protected GraphBuilderConfiguration editGraphBuilderConfiguration(GraphBuilderConfiguration conf) {
+        InvocationPlugin safepointPlugin = new InvocationPlugin() {
+            @Override
+            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver) {
+                b.add(new SafepointNode());
+                return true;
+            }
+        };
+        conf.getPlugins().getInvocationPlugins().register(safepointPlugin, getClass(), "safepoint");
+        return super.editGraphBuilderConfiguration(conf);
+    }
+
+    /*
+     * Safepoint Snippet
+     */
+    private static void safepoint() {
+    }
+
+    private static int numPrimitiveSlots;
+    private static int numReferenceSlots;
+    private static AllocatableValue[] slots;
+
+    private static final LIRTestSpecification readStackValues = new ReadStackValues();
+
+    @SuppressWarnings("unused")
+    @LIRIntrinsic
+    public static void instrinsic(LIRTestSpecification spec) {
+    }
+
+    private static final LIRTestSpecification writeStackValues = new WriteStackValues(JavaConstant.NULL_POINTER, JavaConstant.LONG_0);
+
+    public void testStackObjects() {
+        instrinsic(writeStackValues);
+        safepoint();
+        instrinsic(readStackValues);
+    }
+
+    @Test
+    public void runStackObjects() throws Throwable {
+        int max = ((HotSpotBackend) getBackend()).getRuntime().getVMConfig().maxOopMapStackOffset;
+        Assume.assumeFalse("no limit on oop map size", max == Integer.MAX_VALUE);
+        numPrimitiveSlots = (max / 8) * 2;
+        numReferenceSlots = (max / 8) - 100; // Should be enough margin for all platforms
+        runTest("testStackObjects");
+    }
+}