/*

 * 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 jdk.vm.ci.code;

import java.util.Objects;

import jdk.vm.ci.meta.ResolvedJavaMethod;

/**

 * Represents a code position, that is, a chain of inlined methods with bytecode locations, that is

 * communicated from the compiler to the runtime system. A code position can be used by the runtime

 * system to reconstruct a source-level stack trace for exceptions and to create

 * {@linkplain BytecodeFrame frames} for deoptimization.

 */

public class BytecodePosition {

    private final BytecodePosition caller;

    private final ResolvedJavaMethod method;

    private final int bci;

    /**

     * Constructs a new object representing a given parent/caller, a given method, and a given BCI.

     *

     * @param caller the parent position

     * @param method the method

     * @param bci a BCI such that {@code method.codeSize() == 0 || bci < method.getCodeSize()}. That

     *            is, if code size is 0 then allow any value, otherwise the bci must be less than

     *            the code size.

     */

    public BytecodePosition(BytecodePosition caller, ResolvedJavaMethod method, int bci) {

        assert method != null;

        this.caller = caller;

        this.method = method;

        this.bci = bci;

        int codeSize = method.getCodeSize();

        if (codeSize != 0 && bci >= codeSize) {

            throw new IllegalArgumentException(String.format("bci %d is out of range for %s %d bytes", bci, method.format("%H.%n(%p)"), codeSize));

        }

    }

    /**

     * Converts this code position to a string representation.

     *

     * @return a string representation of this code position

     */

    @Override

    public String toString() {

        return CodeUtil.append(new StringBuilder(100), this).toString();

    }

    /**

     * Deep equality test.

     */

    @Override

    public boolean equals(Object obj) {

        if (obj == this) {

            return true;

        }

        if (obj != null && getClass() == obj.getClass()) {

            BytecodePosition that = (BytecodePosition) obj;

            if (this.bci == that.bci && Objects.equals(this.getMethod(), that.getMethod()) && Objects.equals(this.caller, that.caller)) {

                return true;

            }

        }

        return false;

    }

    @Override

    public int hashCode() {

    }

    /**

     * @return The location within the method, as a bytecode index. The constant {@code -1} may be

     *         used to indicate the location is unknown, for example within code synthesized by the

     *         compiler.

     */

    public int getBCI() {

        return bci;

    }

    /**

     * @return The runtime interface method for this position.

     */

    public ResolvedJavaMethod getMethod() {

        return method;

    }

    /**

     * The position where this position has been called, {@code null} if none.

     */

    public BytecodePosition getCaller() {

        return caller;

    }

    /**

     * Adds a caller to the current position returning the new position.

     */

    public BytecodePosition addCaller(BytecodePosition link) {

        if (getCaller() == null) {

            return new BytecodePosition(link, getMethod(), getBCI());

        } else {

            return new BytecodePosition(getCaller().addCaller(link), getMethod(), getBCI());

        }

    }

}