ReadyMoveNodeGroupList.hh

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    Copyright (c) 2002-2009 Tampere University.
 
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/**
 * @file ReadyMoveNodeGroupList.hh
 *
 * Declaration of ReadyMoveNodeGroupList class.
 *
 * @author Pekka Jääskeläinen 2007 (pjaaskel-no.spam-cs.tut.fi)
 * @note rating: red
 */
 
#ifndef TTA_READY_MOVE_NODE_GROUP_LIST_HH
#define TTA_READY_MOVE_NODE_GROUP_LIST_HH
 
#include <vector>
#include <queue>
 
#include "MoveNode.hh"
#include "Move.hh"
#include "MoveNodeGroup.hh"
 
/**
 * A function object for prioritizing the ready list according to the move's
 * distance from farthest sink node.
 *
 */
class RLPriorityCriticalPath:
    public std::binary_function<MoveNode*, MoveNode*, bool> {
public:
    /**
     * Compares two nodes according to their priority in the ready list.
     *
     * @param a Node a.
     * @param b Node b.
     * @return True if b should be scheduled before a (b greater than a).
     */
    bool operator()(MoveNodeGroup& a, MoveNodeGroup& b) {
 
        if (b.isScheduled()) {
            // keep scheduled MoveNodeSets on a top of a queue
            // so they will be poped out
            return true;
        }
        if (a.isScheduled()) {
            // keep scheduled MoveNodeSets on a top of a queue
            // so they will be poped out
            return false;
        }
        // Compute distances only once, it is expensive operation on graph
        int aSinkDistance = a.maxSinkDistance();
        int bSinkDistance = b.maxSinkDistance();
 
        if (bSinkDistance == aSinkDistance) {
            return b.node(0).nodeID() < a.node(0).nodeID();
        }
        // the higher the sink distance, the higher the priority
        return bSinkDistance > aSinkDistance;
    }
};
 
/**
 * A function object for prioritizing the ready list according to the move's
 * distance from farthest source node. Futher away from source the better.
 *
 */
class RLBUPriorityCriticalPath:
public std::binary_function<MoveNode*, MoveNode*, bool> {
public:
    /**
     * Compares two nodes according to their priority in the ready list.
     *
     * @param a Node a.
     * @param b Node b.
     * @return True if b should be scheduled before a (b greater than a).
     */
    bool operator()(MoveNodeGroup& a, MoveNodeGroup& b) {
        
        if (b.isScheduled()) {
            // keep scheduled MoveNodeSets on a top of a queue
            // so they will be poped out
            return true;
        }
        if (a.isScheduled()) {
            // keep scheduled MoveNodeSets on a top of a queue
            // so they will be poped out
            return false;
        }
        if (a.node(0).move().isControlFlowMove()) {
            // Push control flow move to beginning of the ready list
            return false;
        }
        if (b.node(0).move().isControlFlowMove()) {
            // Push control flow move to beginning of the ready list
            return true;
        }
#if 0
        // also prioritize moves which write the jump guard.
        if (a.writesJumpGuard()) {
            return false;
        }
 
        // also prioritize moves which write the jump guard.
        if (b.writesJumpGuard()) {
            return true;
        }
#endif
        // Compute distances only once, it is expensive operation on graph
        int aSourceDistance = a.maxSourceDistance();
        int bSourceDistance = b.maxSourceDistance();
        if (bSourceDistance == aSourceDistance) {
            int aSinkDistance = a.maxSinkDistance();
            int bSinkDistance = b.maxSinkDistance();
            if (bSinkDistance == aSinkDistance) {
                return b.node(0).nodeID() < a.node(0).nodeID();
            }
            // the lower the sink distance, the higher the priority
            // this priority is better for loop scheduling, to make
            // true tails get scheudled first.
            return bSinkDistance < aSinkDistance;
 
        }
        // the higher the source distance, the higher the priority
        return bSourceDistance > aSourceDistance;
    }
};
 
/// A prioritized list for the ready-to-be-scheduled move node groups.
typedef std::priority_queue<
    MoveNodeGroup, std::vector<MoveNodeGroup>,
    RLPriorityCriticalPath> ReadyMoveNodeGroupList;
 
/// A prioritized list for the ready-to-be-scheduled move node groups.
typedef std::priority_queue<
    MoveNodeGroup, std::vector<MoveNodeGroup>,
    RLBUPriorityCriticalPath> ReadyMoveNodeGroupListBU;
 
#endif