InstructionReferenceManager.hh

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/*
    Copyright (c) 2002-2011 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file InstructionReferenceManager.hh
 *
 * Declaration of InstructionReferenceManager class.
 *
 * The instruction reference handles references to instructions.
 * 
 * The design consists of 3 classes:
 *
 * InstructionReferenceManager: a single high-level object. Contains the
 * external interface, maps to locate a reference to an instruction
 * based on instruction, and ways to iterate over all instruction references.
 *
 * InstructionReference: The class which is shown to a client. Encapsulates
 * a reference into a single instruction. Multiple InstructionReferences
 * may point to a single instruction and these can be freely copied etc.
 * You should not use pointers to these classes, but always copy your 
 * existing objects with copy constructor/assignment into the new one when
 * returning from functions etc.
 *
 * InstructionReferenceImpl: This is internal intermediate implementation 
 * class. It is not shown to the user. There is always exactly one
 * InstructionReferenceImpl per target instruction. 
 * If two instruction references that originally pointed to different 
 * instructions (and so had different InstructionReferenceImpl objects), 
 * these objects are automatically merged and all the internal pointers 
 * and bookkeeping updated accordingly. 
 *
 * Multiple instructionreferences typically point to InstructionReferenceImpl,
 * and instructionReferenceImpl contains pointers to all of these, so it
 * can notify them in case the instructionReferenceImpl is merged with
 * another.
 *
 * @author Ari Metsähalme 2005 (ari.metsahalme-no.spam-tut.fi)
 * @author Heikki Kultala 2009 (heikki.kultala-no.spam-tut.fi)
 * @note rating: red
 */
 
#ifndef TTA_INSTRUCTION_REFERENCE_MANAGER_HH
#define TTA_INSTRUCTION_REFERENCE_MANAGER_HH
 
#include <map>
#include "Exception.hh"
#include "InstructionReferenceImpl.hh"
 
namespace TTAProgram {
 
class Instruction;
class InstructionReference;
class InstructionReferenceImpl;
 
/**
 * Helps in keeping instructions referenced in POM up-to-date.
 *
 * Instructions are not referenced directly, but through an
 * InstructionReference instance. The actual Instruction instance
 * referred can be changed as needed.
 */
class InstructionReferenceManager {
public:
    /// Map for instruction references. faster to search than list.
    typedef std::map<Instruction*, InstructionReferenceImpl*> RefMap;
 
    InstructionReferenceManager();
    virtual ~InstructionReferenceManager();
 
    InstructionReference createReference(Instruction& ins);
    void replace(Instruction& insA, Instruction& insB);
    void clearReferences();
    bool hasReference(Instruction& ins) const;
    unsigned int referenceCount(Instruction& ins) const;
    void referenceDied(Instruction* ins);
 
    void validate();
 
    class Iterator {
    public:
        inline Iterator& operator++(); // ++i
        inline const InstructionReference& operator*() const;
        inline const InstructionReference* operator->() const;
        inline bool operator !=(const Iterator& i) const;
        inline Iterator(RefMap::iterator iter);
        inline Iterator(RefMap::iterator& iter);
    private:
        RefMap::iterator iter_;
    };
        
    inline Iterator begin();
    inline Iterator end();
 
private:
    // disable copying and assignment.
    InstructionReferenceManager(const InstructionReferenceManager&);
    InstructionReferenceManager& operator=(const InstructionReferenceManager&);
 
    /// Instruction references to maintain.
    RefMap references_;
 
};
 
#include "InstructionReferenceManager.icc"
 
}
 
 
#endif