/*
 * Copyright (c) 2009, 2011, 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 com.oracle.graal.api.code;

import java.util.*;

import com.oracle.graal.api.code.CallingConvention.*;
import com.oracle.graal.api.code.Register.*;
import com.oracle.graal.api.meta.*;

/**
 * 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(Kind kind);

    /**
     * Gets the register to which {@link Register#Frame} and {@link Register#CallerFrame} are bound.
     */
    Register getFrameRegister();

    Register getScratchRegister();

    /**
     * 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 target the target platform
     * @param stackOnly ignore registers
     */
    CallingConvention getCallingConvention(Type type, JavaType returnType, JavaType[] parameterTypes, TargetDescription target, boolean stackOnly);

    /**
     * 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 flag specifies whether registers for {@linkplain RegisterFlag#CPU integral} or
     *            {@linkplain RegisterFlag#FPU floating point} parameters are being requested
     * @return the ordered set of registers that may be used to pass parameters in a call conforming
     *         to {@code type}
     */
    Register[] getCallingConventionRegisters(Type type, RegisterFlag flag);

    /**
     * Gets the set of registers that can be used by the register allocator.
     */
    Register[] getAllocatableRegisters();

    /**
     * Gets the set of registers that can be used by the register allocator,
     * {@linkplain Register#categorize(Register[]) categorized} by register
     * {@linkplain RegisterFlag flags}.
     * 
     * @return a map from each {@link RegisterFlag} constant to the list of
     *         {@linkplain #getAllocatableRegisters() allocatable} registers for which the flag is
     *         set
     * 
     */
    EnumMap<RegisterFlag, Register[]> getCategorizedAllocatableRegisters();

    /**
     * Gets the registers whose values must be preserved by a method across any call it makes.
     */
    Register[] getCallerSaveRegisters();

    /**
     * Gets the layout of the callee save area of this register configuration.
     * 
     * @return {@code null} if there is no callee save area
     */
    CalleeSaveLayout getCalleeSaveLayout();

    /**
     * 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
     * @see Register#categorize(Register[])
     */
    RegisterAttributes[] getAttributesMap();

    /**
     * Gets the register corresponding to a runtime-defined role.
     * 
     * @param id the identifier of a runtime-defined register role
     * @return the register playing the role specified by {@code id}
     */
    Register getRegisterForRole(int id);
}