mem_dep_unit.hh

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 * Authors: Kevin Lim
 */

#ifndef __CPU_O3_MEM_DEP_UNIT_HH__
#define __CPU_O3_MEM_DEP_UNIT_HH__

#include <list>
#include <memory>
#include <set>
#include <unordered_map>

#include "base/statistics.hh"
#include "cpu/inst_seq.hh"
#include "debug/MemDepUnit.hh"

struct SNHash {
    size_t operator() (const InstSeqNum &seq_num) const {
        unsigned a = (unsigned)seq_num;
        unsigned hash = (((a >> 14) ^ ((a >> 2) & 0xffff))) & 0x7FFFFFFF;

        return hash;
    }
};

struct DerivO3CPUParams;

template <class Impl>
class InstructionQueue;

template <class MemDepPred, class Impl>
class MemDepUnit
{
  protected:
    std::string _name;

  public:
    typedef typename Impl::DynInstPtr DynInstPtr;
    typedef typename Impl::DynInstConstPtr DynInstConstPtr;

    MemDepUnit();

    MemDepUnit(DerivO3CPUParams *params);

    ~MemDepUnit();

    std::string name() const { return _name; }

    void init(DerivO3CPUParams *params, ThreadID tid);

    void regStats();

    bool isDrained() const;

    void drainSanityCheck() const;

    void takeOverFrom();

    void setIQ(InstructionQueue<Impl> *iq_ptr);

    void insert(const DynInstPtr &inst);

    void insertNonSpec(const DynInstPtr &inst);

    void insertBarrier(const DynInstPtr &barr_inst);

    void regsReady(const DynInstPtr &inst);

    void nonSpecInstReady(const DynInstPtr &inst);

    void reschedule(const DynInstPtr &inst);

    void replay();

    void completed(const DynInstPtr &inst);

    void completeBarrier(const DynInstPtr &inst);

    void wakeDependents(const DynInstPtr &inst);

    void squash(const InstSeqNum &squashed_num, ThreadID tid);

    void violation(const DynInstPtr &store_inst,
                   const DynInstPtr &violating_load);

    void issue(const DynInstPtr &inst);

    void dumpLists();

  private:
    typedef typename std::list<DynInstPtr>::iterator ListIt;

    class MemDepEntry;

    typedef std::shared_ptr<MemDepEntry> MemDepEntryPtr;

    class MemDepEntry {
      public:
        MemDepEntry(const DynInstPtr &new_inst)
            : inst(new_inst), regsReady(false), memDepReady(false),
              completed(false), squashed(false)
        {
#ifdef DEBUG
            ++memdep_count;

            DPRINTF(MemDepUnit, "Memory dependency entry created.  "
                    "memdep_count=%i %s\n", memdep_count, inst->pcState());
#endif
        }

        ~MemDepEntry()
        {
            for (int i = 0; i < dependInsts.size(); ++i) {
                dependInsts[i] = NULL;
            }
#ifdef DEBUG
            --memdep_count;

            DPRINTF(MemDepUnit, "Memory dependency entry deleted.  "
                    "memdep_count=%i %s\n", memdep_count, inst->pcState());
#endif
        }

        std::string name() const { return "memdepentry"; }

        DynInstPtr inst;

        ListIt listIt;

        std::vector<MemDepEntryPtr> dependInsts;

        bool regsReady;
        bool memDepReady;
        bool completed;
        bool squashed;

#ifdef DEBUG
        static int memdep_count;
        static int memdep_insert;
        static int memdep_erase;
#endif
    };

    inline MemDepEntryPtr &findInHash(const DynInstConstPtr& inst);

    inline void moveToReady(MemDepEntryPtr &ready_inst_entry);

    typedef std::unordered_map<InstSeqNum, MemDepEntryPtr, SNHash> MemDepHash;

    typedef typename MemDepHash::iterator MemDepHashIt;

    MemDepHash memDepHash;

    std::list<DynInstPtr> instList[Impl::MaxThreads];

    std::list<DynInstPtr> instsToReplay;

    MemDepPred depPred;

    bool loadBarrier;
    InstSeqNum loadBarrierSN;
    bool storeBarrier;
    InstSeqNum storeBarrierSN;

    InstructionQueue<Impl> *iqPtr;

    int id;

    Stats::Scalar insertedLoads;
    Stats::Scalar insertedStores;
    Stats::Scalar conflictingLoads;
    Stats::Scalar conflictingStores;
};

#endif // __CPU_O3_MEM_DEP_UNIT_HH__