/*******************************************************************************
 * Copyright IBM Corp. and others 2000
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution
 * and is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License, v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception [1] and GNU General Public
 * License, version 2 with the OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 *******************************************************************************/

#ifndef ISOLSTOR_INCL
#define ISOLSTOR_INCL

#include <stdint.h>
#include "il/Node.hpp"
#include "optimizer/Optimization.hpp"
#include "optimizer/OptimizationManager.hpp"

class TR_BitVector;
class TR_RegionStructure;
class TR_Structure;
class TR_UseDefInfo;

namespace TR {
class SymbolReference;
class Block;
class TreeTop;
} // namespace TR
template<class T> class TR_Array;

// Isolated Store Elimination
//
// Extends local dead store elimination; removes stores to any
// locals that are never used in the entire method. Such local
// stores might be created after commoning (local and global) and
// local dead store elimination may not be able to catch all the cases.
//
class TR_IsolatedStoreElimination : public TR::Optimization {
public:
    // Performs isolated store elimination
    //
    TR_IsolatedStoreElimination(TR::OptimizationManager *manager);

    static TR::Optimization *create(TR::OptimizationManager *manager)
    {
        return new (manager->allocator()) TR_IsolatedStoreElimination(manager);
    }

    virtual int32_t perform();
    virtual const char *optDetailString() const throw();

protected:
    char *_optDetailsMessage;
    bool _mustUseUseDefInfo; // temporary

private:
    bool _deferUseDefInfoInvalidation; // true if useDefInfo is invalidated during performWithUseDefInfo() but
                                       // useDefInfo is still used (conservatively) later on in the optimization.

    int32_t performWithUseDefInfo();
    int32_t performWithoutUseDefInfo();
    bool canRemoveStoreNode(TR::Node *node);
    void collectDefParentInfo(int32_t defIndex, TR::Node *, TR_UseDefInfo *);
    bool groupIsolatedStores(int32_t defIndex, TR_BitVector *, TR_UseDefInfo *);
    void examineNode(TR::Node *, vcount_t visitCount, bool);

    void performDeadStructureRemoval(TR_UseDefInfo *);
    bool findStructuresAndNodesUsedIn(TR_UseDefInfo *, TR_Structure *, vcount_t, TR_BitVector *, TR_BitVector *,
        bool *);
    bool markNodesAndLocateSideEffectIn(TR::Node *, vcount_t, TR_BitVector *, TR_BitVector *);

    void analyzeSingleBlockLoop(TR_RegionStructure *, TR::Block *);

    void removeRedundantSpills();

    enum defStatus {
        notVisited = 0,
        inTransit,
        notToBeRemoved,
        toBeRemoved,
        doNotExamine
    };

    TR_BitVector *_usedSymbols;
    TR_Array<TR::Node *> *_storeNodes;
    TR_Array<int32_t> *_defParentOfUse;
    TR_Array<defStatus> *_defStatus;
    TR_Array<TR_BitVector *> *_groupsOfStoreNodes;
    TR_BitVector *_trivialDefs;

    TR::TreeTop *_currentTree;
};

#endif
