/*

 * 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

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 */

package org.graalvm.compiler.nodes.java;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.MetaAccessProvider;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.core.common.type.TypeReference;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.nodeinfo.InputType;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.AbstractBeginNode;

import org.graalvm.compiler.nodes.BeginStateSplitNode;

import org.graalvm.compiler.nodes.InvokeWithExceptionNode;

import org.graalvm.compiler.nodes.KillingBeginNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.memory.MemoryCheckpoint;

import org.graalvm.compiler.nodes.spi.Lowerable;

import org.graalvm.compiler.nodes.spi.LoweringTool;

import jdk.internal.vm.compiler.word.LocationIdentity;

import static org.graalvm.compiler.nodeinfo.InputType.Memory;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_8;

import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_8;

/**

 * The entry to an exception handler with the exception coming from a call (as opposed to a local

 * throw instruction or implicit exception).

 */

@NodeInfo(allowedUsageTypes = Memory, cycles = CYCLES_8, size = SIZE_8)

public final class ExceptionObjectNode extends BeginStateSplitNode implements Lowerable, MemoryCheckpoint.Single {

    public static final NodeClass<ExceptionObjectNode> TYPE = NodeClass.create(ExceptionObjectNode.class);

    public ExceptionObjectNode(MetaAccessProvider metaAccess) {

        super(TYPE, StampFactory.objectNonNull(TypeReference.createTrustedWithoutAssumptions(metaAccess.lookupJavaType(Throwable.class))));

    }

    @Override

        return LocationIdentity.any();

    }

    /**

     * An exception handler is an entry point to a method from the runtime and so represents an

     * instruction that cannot be re-executed. It therefore needs a frame state.

     */

    @Override

    public boolean hasSideEffect() {

        return true;

    }

    @Override

    public void lower(LoweringTool tool) {

        if (graph().getGuardsStage() == StructuredGraph.GuardsStage.FIXED_DEOPTS) {

            /*

             * Now the lowering to BeginNode+LoadExceptionNode can be performed, since no more

             * deopts can float in between the begin node and the load exception node.

             */

            AbstractBeginNode entry = graph().add(KillingBeginNode.create(locationsKilledByInvoke));

            LoadExceptionObjectNode loadException = graph().add(new LoadExceptionObjectNode(stamp(NodeView.DEFAULT)));

            loadException.setStateAfter(stateAfter());

            replaceAtUsages(InputType.Value, loadException);

            graph().replaceFixedWithFixed(this, entry);

            entry.graph().addAfterFixed(entry, loadException);

            loadException.lower(tool);

        }

    }

    @Override

    public boolean verify() {

        assertTrue(stateAfter() != null, "an exception handler needs a frame state");

        assertTrue(stateAfter().stackSize() == 1 && stateAfter().stackAt(0).stamp(NodeView.DEFAULT).getStackKind() == JavaKind.Object,

                        "an exception handler's frame state must have only the exception on the stack");

        return super.verify();

    }

}