mem_dep_unit.hh

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#ifndef __CPU_O3_MEM_DEP_UNIT_HH__
#define __CPU_O3_MEM_DEP_UNIT_HH__
 
#include <list>
#include <memory>
#include <set>
#include <unordered_map>
#include <unordered_set>
 
#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;
    typedef typename Impl::O3CPU O3CPU;
 
    MemDepUnit();
 
    MemDepUnit(const DerivO3CPUParams &params);
 
    ~MemDepUnit();
 
    std::string name() const { return _name; }
 
    void init(const DerivO3CPUParams &params, ThreadID tid, O3CPU *cpu);
 
    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 completeInst(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:
 
    void completed(const DynInstPtr &inst);
 
    void wakeDependents(const DynInstPtr &inst);
 
    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), memDeps(0),
              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;
        int memDeps;
        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;
 
    std::unordered_set<InstSeqNum> loadBarrierSNs;
 
    std::unordered_set<InstSeqNum> storeBarrierSNs;
 
    bool hasLoadBarrier() const { return !loadBarrierSNs.empty(); }
 
    bool hasStoreBarrier() const { return !storeBarrierSNs.empty(); }
 
    void insertBarrierSN(const DynInstPtr &barr_inst);
 
    InstructionQueue<Impl> *iqPtr;
 
    int id;
    struct MemDepUnitStats : public Stats::Group
    {
        MemDepUnitStats(Stats::Group *parent);
        Stats::Scalar insertedLoads;
        Stats::Scalar insertedStores;
        Stats::Scalar conflictingLoads;
        Stats::Scalar conflictingStores;
    } stats;
};
 
#endif // __CPU_O3_MEM_DEP_UNIT_HH__