pattern_functor.h

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *
 *   http://www.apache.org/licenses/LICENSE-2.0
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#ifndef TVM_RELAY_PATTERN_FUNCTOR_H_
#define TVM_RELAY_PATTERN_FUNCTOR_H_

#include <tvm/node/functor.h>
#include <tvm/relay/error.h>

#include <string>
#include <unordered_map>
#include <utility>

#include "./adt.h"
#include "./expr.h"
#include "./op.h"

namespace tvm {
namespace relay {

template <typename FType>
class PatternFunctor;

// functions to be overriden.
#define PATTERN_FUNCTOR_DEFAULT \
  { return VisitPatternDefault_(op, std::forward<Args>(args)...); }

#define RELAY_PATTERN_FUNCTOR_DISPATCH(OP)                                                    \
  vtable.template set_dispatch<OP>([](const ObjectRef& n, TSelf* self, Args... args) {        \
    return self->VisitPattern_(static_cast<const OP*>(n.get()), std::forward<Args>(args)...); \
  });

template <typename R, typename... Args>
class PatternFunctor<R(const Pattern& n, Args...)> {
 private:
  using TSelf = PatternFunctor<R(const Pattern& n, Args...)>;
  using FType = tvm::NodeFunctor<R(const ObjectRef& n, TSelf* self, Args...)>;

 public:
  using result_type = R;
  virtual ~PatternFunctor() {}
  R operator()(const Pattern& n, Args... args) {
    return VisitPattern(n, std::forward<Args>(args)...);
  }
  virtual R VisitPattern(const Pattern& n, Args... args) {
    ICHECK(n.defined());
    static FType vtable = InitVTable();
    return vtable(n, this, std::forward<Args>(args)...);
  }
  // Functions that can be overriden by subclass
  virtual R VisitPattern_(const PatternWildcardNode* op, Args... args) PATTERN_FUNCTOR_DEFAULT;
  virtual R VisitPattern_(const PatternVarNode* op, Args... args) PATTERN_FUNCTOR_DEFAULT;
  virtual R VisitPattern_(const PatternConstructorNode* op, Args... args) PATTERN_FUNCTOR_DEFAULT;
  virtual R VisitPattern_(const PatternTupleNode* op, Args... args) PATTERN_FUNCTOR_DEFAULT;
  virtual R VisitPatternDefault_(const Object* op, Args...) {
    LOG(FATAL) << "Do not have a default for " << op->GetTypeKey();
    throw;
  }

 private:
  // initialize the vtable.
  static FType InitVTable() {
    FType vtable;
    // Set dispatch
    RELAY_PATTERN_FUNCTOR_DISPATCH(PatternWildcardNode);
    RELAY_PATTERN_FUNCTOR_DISPATCH(PatternVarNode);
    RELAY_PATTERN_FUNCTOR_DISPATCH(PatternConstructorNode);
    RELAY_PATTERN_FUNCTOR_DISPATCH(PatternTupleNode);
    return vtable;
  }
};

class PatternVisitor : public ::tvm::relay::PatternFunctor<void(const Pattern& n)> {
 public:
  void VisitPattern_(const PatternWildcardNode* op) override;
  void VisitPattern_(const PatternVarNode* op) override;
  void VisitPattern_(const PatternConstructorNode* op) override;
  void VisitPattern_(const PatternTupleNode* op) override;
  virtual void VisitType(const Type& t);
  virtual void VisitVar(const Var& v);
  virtual void VisitConstructor(const Constructor& c);
};

class PatternMutator : public ::tvm::relay::PatternFunctor<Pattern(const Pattern&)> {
 public:
  Pattern Mutate(const Pattern& pat);
  Pattern VisitPattern_(const PatternWildcardNode* op) override;
  Pattern VisitPattern_(const PatternVarNode* op) override;
  Pattern VisitPattern_(const PatternConstructorNode* op) override;
  Pattern VisitPattern_(const PatternTupleNode* op) override;
  virtual Type VisitType(const Type& t);
  virtual Var VisitVar(const Var& v);
  virtual Constructor VisitConstructor(const Constructor& c);

 private:
  std::unordered_map<Var, Var, ObjectPtrHash, ObjectPtrEqual> var_map_;
};

}  // namespace relay
}  // namespace tvm
#endif  // TVM_RELAY_PATTERN_FUNCTOR_H_