/*

 * Copyright (c) 2009, 2016, 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 jdk.vm.ci.code;

import jdk.vm.ci.code.CallingConvention.Type;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.JavaType;

import jdk.vm.ci.meta.PlatformKind;

import jdk.vm.ci.meta.ValueKind;

/**

 * A register configuration binds roles and {@linkplain RegisterAttributes attributes} to physical

 * registers.

 */

public interface RegisterConfig {

    /**

     * Gets the register to be used for returning a value of a given kind.

     */

    Register getReturnRegister(JavaKind kind);

    /**

     * Gets the maximum allowed size of the frame.

     */

    default int getMaximumFrameSize() {

        return Integer.MAX_VALUE;

    }

    /**

     * Gets the register used as the frame pointer. Spill slots and outgoing stack-based arguments

     * are addressed relative to this register.

     */

    Register getFrameRegister();

    /**

     * Gets the calling convention describing how arguments are passed.

     *

     * @param type the type of calling convention being requested

     * @param returnType the return type (can be null for methods returning {@code void})

     * @param parameterTypes the types of the arguments of the call

     * @param valueKindFactory the factory to create custom {@link ValueKind ValueKinds}

     */

    CallingConvention getCallingConvention(Type type, JavaType returnType, JavaType[] parameterTypes, ValueKindFactory<?> valueKindFactory);

    /**

     * Gets the ordered set of registers that are can be used to pass parameters according to a

     * given calling convention.

     *

     * @param type the type of calling convention

     * @param kind specifies what kind of registers is being requested

     * @return the ordered set of registers that may be used to pass parameters in a call conforming

     *         to {@code type}

     */

    RegisterArray getCallingConventionRegisters(Type type, JavaKind kind);

    /**

     * Gets the set of all registers that might be used by the register allocator.

     */

    RegisterArray getAllocatableRegisters();

    /**

     * Filters a set of registers and returns only those that can be used by the register allocator

     * for a value of a particular kind.

     */

    RegisterArray filterAllocatableRegisters(PlatformKind kind, RegisterArray registers);

    /**

     * Gets the registers whose values must be preserved by a method across any call it makes.

     */

    RegisterArray getCallerSaveRegisters();

    /**

     * Gets the registers whose values must be preserved by the callee.

     */

    RegisterArray getCalleeSaveRegisters();

    /**

     * Gets a map from register {@linkplain Register#number numbers} to register

     * {@linkplain RegisterAttributes attributes} for this register configuration.

     *

     * @return an array where an element at index i holds the attributes of the register whose

     *         number is i

     */

    RegisterAttributes[] getAttributesMap();

    /**

     * Determines if all {@link #getAllocatableRegisters() allocatable} registers are

     * {@link #getCallerSaveRegisters() caller saved}.

     */

    boolean areAllAllocatableRegistersCallerSaved();

}