Class CVPLatticeVal

lib/indcallsolver/CustomCVPPass.cpp:65–115

The lattice value type used by our custom lattice function. It holds the lattice state, and a set of functions.

/// The lattice value type used by our custom lattice function. It holds the
/// lattice state, and a set of functions.
class CVPLatticeVal {
public:
  /// The states of the lattice values. Only the FunctionSet state is
  /// interesting. It indicates the set of functions to which an LLVM value may
  /// refer.
  enum CVPLatticeStateTy { Undefined, FunctionSet, Overdefined, Untracked };

  /// Comparator for sorting the functions set. We want to keep the order
  /// deterministic for testing, etc.
  struct Compare {
    bool operator()(const Function *LHS, const Function *RHS) const {
      return LHS->getName() < RHS->getName();
    }
  };

  CVPLatticeVal() : LatticeState(Undefined) {}
  CVPLatticeVal(CVPLatticeStateTy LatticeState) : LatticeState(LatticeState) {}
  CVPLatticeVal(std::vector<Function *> &&Functions)
      : LatticeState(FunctionSet), Functions(std::move(Functions)) {
    assert(std::is_sorted(this->Functions.begin(), this->Functions.end(),
                          Compare()));
  }

  /// Get a reference to the functions held by this lattice value. The number
  /// of functions will be zero for states other than FunctionSet.
  const std::vector<Function *> &getFunctions() const { return Functions; }

  /// Returns true if the lattice value is in the FunctionSet state.
  bool isFunctionSet() const { return LatticeState == FunctionSet; }

  bool operator==(const CVPLatticeVal &RHS) const {
    return LatticeState == RHS.LatticeState && Functions == RHS.Functions;
  }

  bool operator!=(const CVPLatticeVal &RHS) const {
    return LatticeState != RHS.LatticeState || Functions != RHS.Functions;
  }

private:
  /// Holds the state this lattice value is in.
  CVPLatticeStateTy LatticeState;

  /// Holds functions indicating the possible targets of call sites. This set
  /// is empty for lattice values in the undefined, overdefined, and untracked
  /// states. The maximum size of the set is controlled by
  /// MaxFunctionsPerValue. Since most LLVM values are expected to be in
  /// uninteresting states (i.e., overdefined), CVPLatticeVal objects should be
  /// small and efficiently copyable.
  // FIXME: This could be a TinyPtrVector and/or merge with LatticeState.
  std::vector<Function *> Functions;
};

/// The custom lattice function used by the generic sparse propagation solver.
/// It handles merging lattice values and computing new lattice values for