ControlFlowEdge.cc

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file ControlFlowEdge.cc
 *
 * Prototype of graph-based program representation: implementation of graph
 * edge.
 *
 * @author Andrea Cilio 2005 (cilio-no.spam-cs.tut.fi)
 * @author Vladimir Guzma 2006 (vladimir.guzma-no.spam-tut.fi)
 * @note rating: red
 */
 
#include "ControlFlowEdge.hh"
#include "Move.hh"
#include "MoveGuard.hh"
#include "Operation.hh"
#include "Terminal.hh"
 
/**
 * Constructor creates Control Flow Edge of given type
 *
 * @param edgePredicate The truth value of edge (or normal)
 * @param edgeType Define if edge represents jump, if false the it is call
 */
ControlFlowEdge::ControlFlowEdge(
    CFGEdgePredicate edgePredicate,
    CFGEdgeType edgeType) :
    edgePredicate_(edgePredicate), edgeType_(edgeType), backEdge_(false) {
}
 
/**
 * Destructor
 */
ControlFlowEdge::~ControlFlowEdge() { }
 
/**
 * Returns type as a string. Helper for graph output to dot file.
 *
 * @return String representing type of edge.
 */
TCEString
ControlFlowEdge::toString() const {
    TCEString result = "";
    if (isJumpEdge()) {
        result += "Jump_";
    }
    if (isFallThroughEdge()) {
        result += "FallThrough_";
    }
    if (isCallPassEdge()) {
        result += "CallPass_";
    }
    if (isBackEdge()) {
        result += "BackEdge_";
    }
    if (isNormalEdge()) {
        result += "normal";
    }
    if (isTrueEdge()) {
        result += "true";
    }
    if (isFalseEdge()) {
        result += "false";
    }
    if (isLoopBreakEdge()) {
        result += "break";
    }
    return result;
}
 
/**
 * Returns true if object represents ControlFlowEdge.
 *
 * @return True if object is control flow edge
 */
bool
ControlFlowEdge::isControlFlowEdge() const {
    return true;
}
/**
 * Returns true if the edge is representing unconditional jump
 *
 * @return True if jump is not guarded
 */
bool
ControlFlowEdge::isNormalEdge() const {
    return edgePredicate_ == CFLOW_EDGE_NORMAL;
}
 
/**
 * Returns true if edge represents conditional control flow that is
 * taken if condition evaluates to true.
 *
 * @return True if edge represents True path
 */
bool
ControlFlowEdge::isTrueEdge() const {
    return edgePredicate_ == CFLOW_EDGE_TRUE;
}
/**
 * Returns true if edge represents conditional control flow that is
 * taken if condition evaluates to false.
 *
 * @return True if edge represents False path
 */
bool
ControlFlowEdge::isFalseEdge() const {
    return edgePredicate_ == CFLOW_EDGE_FALSE;
}
/**
 * Returns true if edge represents control flow over the call in code.
 *
 * @return True if edge is split in basic block when call happened.
 */
bool
ControlFlowEdge::isCallPassEdge() const {
    return edgeType_ == CFLOW_EDGE_CALL;
}
 
/**
 * Returns true if the edge is representing jump.
 *
 * @return True if the edge represents jump.
 */
bool
ControlFlowEdge::isJumpEdge() const {
    return edgeType_ == CFLOW_EDGE_JUMP;
}
 
/**
 * Returns true if the edge is representing fall through.
 *
 * @return True if the edge represents fall through.
 */
bool
ControlFlowEdge::isFallThroughEdge() const {
    return edgeType_ == CFLOW_EDGE_FALLTHROUGH;
}
 
/**
 * Returns true if edge was added to break infinite
 * loop for control dependence computation.
 *
 * @return True if edge was added to break infinite loop
 */
bool
ControlFlowEdge::isLoopBreakEdge() const {
    return edgePredicate_ == CFLOW_EDGE_LOOP_BREAK;
}
 
/**
 * Returns true if edge is loop back edge
 *
 * @return True if edge is loop back edge
 */
bool
ControlFlowEdge::isBackEdge() const {
    return backEdge_;
}
 
/**
 * Creates an edge predicate based on the guard of a move
 */
ControlFlowEdge::CFGEdgePredicate
ControlFlowEdge::edgePredicateFromMove(const TTAProgram::Move& move) {
    if (move.isUnconditional()) {
        if (move.isTriggering()) {
            Operation& o = move.destination().operation();
            if (o.name() == "BNZ" || o.name() == "IRFJUMPNZ" ||
                o.name() == "BNZ1" || o.name() == "IRFJUMPNZ1") {
                return ControlFlowEdge::CFLOW_EDGE_TRUE;
            }
            if (o.name() == "BZ" || o.name() == "IRFJUMPZ" ||
                o.name() == "BZ1" || o.name() == "IRFJUMPZ1") {
                return ControlFlowEdge::CFLOW_EDGE_FALSE;
            }
        } else {
            Operation& o = move.destination().hintOperation();
            if (&o != &NullOperation::instance()) {
                if (o.name() == "BNZ" || o.name() == "IRFJUMPNZ" ||
                    o.name() == "BNZ1" || o.name() == "IRFJUMPNZ1") {
                    return ControlFlowEdge::CFLOW_EDGE_TRUE;
                }
                if (o.name() == "BZ" || o.name() == "IRFJUMPZ" ||
                    o.name() == "BZ1" || o.name() == "IRFJUMPZ1") {
                    return ControlFlowEdge::CFLOW_EDGE_FALSE;
                }
            }
        }
        return ControlFlowEdge::CFLOW_EDGE_NORMAL;
    }
    TTAProgram::MoveGuard& mg = move.guard();
    return mg.isInverted() ?
        ControlFlowEdge::CFLOW_EDGE_FALSE :
        ControlFlowEdge::CFLOW_EDGE_TRUE;
}