stack_dist_calc.hh

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#ifndef __MEM_STACK_DIST_CALC_HH__
#define __MEM_STACK_DIST_CALC_HH__
 
#include <limits>
#include <map>
#include <vector>
 
#include "base/types.hh"
 
namespace gem5
{
 
class StackDistCalc
{
 
  private:
 
    struct Node;
 
    typedef std::map<uint64_t, Node*> IndexNodeMap;
    typedef std::map<Addr, uint64_t> AddressIndexMap;
    typedef std::vector<IndexNodeMap> TreeType;
 
    uint64_t getSum(Node* node, bool from_left, uint64_t sum_from_below,
                    uint64_t stack_dist, uint64_t level) const;
 
    uint64_t getSumsLeavesToRoot(Node* node) const;
 
    uint64_t updateSum(Node* node,
                       bool from_left, uint64_t sum_from_below, uint64_t level,
                       uint64_t stack_dist, bool discard_node);
 
    uint64_t updateSumsLeavesToRoot(Node* node, bool is_new_leaf);
 
    void updateTree();
 
    void sanityCheckTree(const Node* node, uint64_t level = 0) const;
 
    uint64_t getIndex() const { return index; }
 
    uint64_t getTreeDepth() const { return tree.size() - 1; }
 
    void printStack(int n = 5) const;
 
    uint64_t verifyStackDist(const Addr r_address,
                             bool update_stack = false);
 
  public:
    StackDistCalc(bool verify_stack = false);
 
    ~StackDistCalc();
 
    static constexpr uint64_t Infinity = std::numeric_limits<uint64_t>::max();
 
 
    std::pair<uint64_t, bool> calcStackDist(const Addr r_address,
                                            bool mark = false);
 
    std::pair<uint64_t, bool> calcStackDistAndUpdate(const Addr r_address,
                                                     bool addNewNode = true);
 
  private:
 
    struct Node
    {
        // Sum of the left children
        uint64_t sumLeft;
 
        // Sum of the right children
        uint64_t sumRight;
 
        // Flag to indicate that sumLeft has gone from non-zero value to 0
        bool discardLeft;
 
        // Flag to indicate that sumRight has gone from non-zero value to 0
        bool discardRight;
 
        // Index of the current element in the Map
        uint64_t nodeIndex;
 
        // Pointer to the parent
        Node* parent;
 
        // Flag to mark the node as the right/left child
        bool isLeftNode;
 
        bool isMarked;
 
        Node() : sumLeft(0), sumRight(0), discardLeft(false),
                 discardRight(false), nodeIndex(0),
                 parent(nullptr), isLeftNode(true), isMarked(false)
        { }
    };
 
    uint64_t index;
 
    // Binary tree of partial sums
    TreeType tree;
 
    // Hash map which returns last seen index of each address
    AddressIndexMap aiMap;
 
    // Keeps count of number of the next unique index for each
    // level in the tree
    std::vector<uint64_t> nextIndex;
 
    // Dummy Stack for verification
    std::vector<uint64_t> stack;
 
    // Flag to enable verification of stack. (Slows down the simulation)
    const bool verifyStack;
};
 
} // namespace gem5
 
#endif //__STACK_DIST_CALC_HH__