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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package org.graalvm.compiler.hotspot.phases;

import static org.graalvm.compiler.nodes.ConstantNode.getConstantNodes;

import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.type.StampTool;
import org.graalvm.compiler.phases.VerifyPhase;
import org.graalvm.compiler.phases.tiers.PhaseContext;

import jdk.vm.ci.hotspot.HotSpotObjectConstant;
import jdk.vm.ci.meta.JavaKind;

Checks for illegal object constants in a graph processed for AOT compilation. 
See Also:
LoadJavaMirrorWithKlassPhase/**
 * Checks for {@link #isIllegalObjectConstant(ConstantNode) illegal} object constants in a graph
 * processed for AOT compilation.
 *
 * @see LoadJavaMirrorWithKlassPhase
 */
public class AheadOfTimeVerificationPhase extends VerifyPhase<PhaseContext> {

    @Override
    protected boolean verify(StructuredGraph graph, PhaseContext context) {
        for (ConstantNode node : getConstantNodes(graph)) {
            if (isIllegalObjectConstant(node)) {
                throw new VerificationError("illegal object constant: " + node);
            }
        }
        return true;
    }

    public static boolean isIllegalObjectConstant(ConstantNode node) {
        return isObject(node) && !isNullReference(node) && !isInternedString(node) && !isDirectMethodHandle(node) && !isBoundMethodHandle(node);
    }

    private static boolean isObject(ConstantNode node) {
        return node.getStackKind() == JavaKind.Object;
    }

    private static boolean isNullReference(ConstantNode node) {
        return isObject(node) && node.isNullConstant();
    }

    private static boolean isDirectMethodHandle(ConstantNode node) {
        if (!isObject(node)) {
            return false;
        }
        return "Ljava/lang/invoke/DirectMethodHandle;".equals(StampTool.typeOrNull(node).getName());
    }

    private static boolean isBoundMethodHandle(ConstantNode node) {
        if (!isObject(node)) {
            return false;
        }
        return StampTool.typeOrNull(node).getName().startsWith("Ljava/lang/invoke/BoundMethodHandle");
    }

    private static boolean isInternedString(ConstantNode node) {
        if (!isObject(node)) {
            return false;
        }

        HotSpotObjectConstant c = (HotSpotObjectConstant) node.asConstant();
        return c.isInternedString();
    }
}