MemoryAliasAnalyzer.hh

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
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    the rights to use, copy, modify, merge, publish, distribute, sublicense,
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    Software is furnished to do so, subject to the following conditions:
 
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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/*
 * @file MemoryAliasAnalyzer.hh
 *
 * Declaration of Memory Alias Analyzer interface
 *
 * @author Heikki Kultala 2006-2009 (heikki.kultala-no.spam-tut.fi)
 * @note rating: red
 */
 
#ifndef TTA_MEMORY_ALIAS_ANALYZER_HH
#define TTA_MEMORY_ALIAS_ANALYZER_HH
 
namespace TTAProgram {
    class Procedure;
}
 
class ProgramOperation;
class DataDependenceGraph;
class Operation;
class MoveNode;
 
#include "MoveNodeUse.hh"
 
class MemoryAliasAnalyzer {
public:
 
    enum AliasingResult { ALIAS_FALSE = 0,
                          // Only Use ALIAS_TRUE if they really fully alias.
                          // It's used for transitivity optimizations.
                          ALIAS_TRUE  = 1,
                          ALIAS_UNKNOWN = 2,
                          ALIAS_PARTIAL = 3};
 
    virtual void initProcedure(TTAProgram::Procedure&) {}
 
    virtual AliasingResult analyze(
        DataDependenceGraph& ddg, const ProgramOperation& pop1, 
        const ProgramOperation& pop2, MoveNodeUse::BBRelation bbInfo) = 0;
 
    /**
     * Checks whether the analyzer knows anything about the address.
     * 
     * ie. if it can return true or false to some query 
     * concerning this address.
     * 
     * @return true if analyzer can know something about the address.
     */
    virtual bool isAddressTraceable(
        DataDependenceGraph& ddg,
        const ProgramOperation& pop) = 0;
 
    virtual ~MemoryAliasAnalyzer() {}
protected:
    AliasingResult compareIndeces(
        int index1, 
        int index2, 
        const ProgramOperation& pop1, 
        const ProgramOperation& pop2);
    static const MoveNode* addressOperandMove(const ProgramOperation&po);
 
    struct TwoPartAddressOperandDetection {
        enum OffsetOperation { NOT_FOUND, ADD, SUB };
        OffsetOperation offsetOperation;
        int operand1;
        int operand2;
        TwoPartAddressOperandDetection() : 
            offsetOperation(NOT_FOUND), operand1(0), operand2(0) {}
 
        void clear() {
            offsetOperation = NOT_FOUND;
            operand1 = 0;
            operand2 = 0;
        }
    };
 
    static TwoPartAddressOperandDetection findTwoPartAddressOperands(
        const ProgramOperation& po);
 
    static  const MoveNode* searchLoopIndexBasedIncrement(
        DataDependenceGraph& ddg, const MoveNode &mn, long& loopIncrement);
 
    static const MoveNode* findIncrement(const MoveNode& mn, long& increment);
 
    static const MoveNode* detectConstantScale(const MoveNode& mn, int &shiftAmount);
private:
    unsigned int mausOfOperation(const Operation& op);
};
 
#endif