expr.h

Go to the documentation of this file.

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
#ifndef TVM_RELAX_EXPR_H_
#define TVM_RELAX_EXPR_H_
 
#include <tvm/ir/expr.h>
#include <tvm/ir/function.h>
#include <tvm/ir/source_map.h>
#include <tvm/node/node.h>
#include <tvm/relax/type.h>
#include <tvm/runtime/container/array.h>
#include <tvm/runtime/container/map.h>
#include <tvm/runtime/object.h>
#include <tvm/tir/expr.h>
#include <tvm/tir/op.h>
 
#include <functional>
 
namespace tvm {
namespace relax {
 
using Expr = RelaxExpr;
using ExprNode = RelaxExprNode;
class IdNode : public Object {
 public:
  String name_hint;
 
  void VisitAttrs(tvm::AttrVisitor* v) { v->Visit("name_hint", &name_hint); }
 
  bool SEqualReduce(const IdNode* other, SEqualReducer equal) const {
    return equal.FreeVarEqualImpl(this, other);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce.FreeVarHashImpl(this); }
 
  static constexpr const char* _type_key = "relax.Id";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(IdNode, Object);
};
 
class Id : public ObjectRef {
 public:
  TVM_DLL explicit Id(String name_hint);
 
  TVM_DEFINE_OBJECT_REF_METHODS(Id, ObjectRef, IdNode);
};
 
class StructInfoNode : public Object {
 public:
  mutable Span span;
 
  static constexpr const char* _type_key = "StructInfo";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  static constexpr const uint32_t _type_child_slots = 7;
  TVM_DECLARE_BASE_OBJECT_INFO(StructInfoNode, Object);
};
 
class StructInfo : public ObjectRef {
 public:
  TVM_DEFINE_OBJECT_REF_METHODS(StructInfo, ObjectRef, StructInfoNode);
};
 
class CallNode : public ExprNode {
 public:
  Expr op;
 
  tvm::Array<Expr> args;
 
  Attrs attrs;
 
  Array<StructInfo> sinfo_args;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("op", &op);
    v->Visit("args", &args);
    v->Visit("attrs", &attrs);
    v->Visit("sinfo_args", &sinfo_args);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const CallNode* other, SEqualReducer equal) const {
    // skip sinfo_args check for primitive ops.
    return equal(op, other->op) && equal(args, other->args) && equal(attrs, other->attrs) &&
           equal(sinfo_args, other->sinfo_args) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(op);
    hash_reduce(args);
    hash_reduce(attrs);
    hash_reduce(sinfo_args);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.Call";
  TVM_DECLARE_FINAL_OBJECT_INFO(CallNode, ExprNode);
};
 
class Call : public Expr {
 public:
  TVM_DLL Call(Expr op, Array<Expr> args, Attrs attrs = Attrs(),
               Array<StructInfo> sinfo_args = Array<StructInfo>(), Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(Call, Expr, CallNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(CallNode);
};
 
Call WithFields(Call call, Optional<Expr> opt_op = Optional<Expr>(),
                Optional<Array<Expr>> opt_args = Optional<Array<Expr>>(),
                Optional<Attrs> opt_attrs = Optional<Attrs>(),
                Optional<Array<StructInfo>> opt_sinfo_args = Optional<Array<StructInfo>>(),
                Optional<Span> opt_span = Optional<Span>());
 
class TupleNode : public ExprNode {
 public:
  tvm::Array<Expr> fields;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("fields", &fields);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const TupleNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from fields.
    return equal(fields, other->fields);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(fields); }
 
  static constexpr const char* _type_key = "relax.expr.Tuple";
  TVM_DECLARE_FINAL_OBJECT_INFO(TupleNode, ExprNode);
};
 
class Tuple : public Expr {
 public:
  TVM_DLL explicit Tuple(tvm::Array<Expr> fields, Span span = Span());
 
  template <typename RelaxExpr, typename = std::enable_if_t<std::is_base_of_v<Expr, RelaxExpr>>>
  TVM_DLL explicit Tuple(tvm::Array<RelaxExpr> fields, Span span = Span())
      : Tuple(fields.Map([](const RelaxExpr& expr) -> Expr { return expr; }), span) {}
 
  TVM_DEFINE_OBJECT_REF_METHODS(Tuple, Expr, TupleNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(TupleNode);
};
 
Tuple WithFields(Tuple tuple, Optional<Array<Expr>> opt_fields = Optional<Array<Expr>>(),
                 Optional<Span> opt_span = Optional<Span>());
 
class TupleGetItemNode : public ExprNode {
 public:
  Expr tuple;
  int index;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("tuple_value", &tuple);
    v->Visit("index", &index);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const TupleGetItemNode* other, SEqualReducer equal) const {
    // struct info can be deterministically tuple and index.
    return equal(tuple, other->tuple) && equal(index, other->index);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(tuple);
    hash_reduce(index);
  }
 
  static constexpr const char* _type_key = "relax.expr.TupleGetItem";
  TVM_DECLARE_FINAL_OBJECT_INFO(TupleGetItemNode, ExprNode);
};
 
class TupleGetItem : public Expr {
 public:
  TVM_DLL TupleGetItem(Expr tuple, int index, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(TupleGetItem, Expr, TupleGetItemNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(TupleGetItemNode);
};
 
TupleGetItem WithFields(TupleGetItem tuple_get_item, Optional<Expr> opt_tuple = Optional<Expr>(),
                        Optional<Integer> opt_index = Optional<Integer>(),
                        Optional<Span> opt_span = Optional<Span>());
 
class LeafExprNode : public ExprNode {
 public:
  static constexpr const char* _type_key = "relax.expr.LeafExpr";
  static constexpr const uint32_t _type_child_slots = 7;
  TVM_DECLARE_BASE_OBJECT_INFO(LeafExprNode, ExprNode);
};
 
class LeafExpr : public Expr {
 public:
  TVM_DEFINE_OBJECT_REF_METHODS(LeafExpr, Expr, LeafExprNode);
};
 
class ShapeExprNode : public LeafExprNode {
 public:
  Array<PrimExpr> values;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("values", &values);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const ShapeExprNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from values.
    return equal(values, other->values);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(values); }
 
  static constexpr const char* _type_key = "relax.expr.ShapeExpr";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(ShapeExprNode, LeafExprNode);
};
 
class ShapeExpr : public LeafExpr {
 public:
  TVM_DLL explicit ShapeExpr(Array<PrimExpr> values, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(ShapeExpr, LeafExpr, ShapeExprNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(ShapeExprNode);
};
 
class VarNode : public LeafExprNode {
 public:
  Id vid;
 
  const String& name_hint() const { return vid->name_hint; }
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("vid", &vid);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const VarNode* other, SEqualReducer equal) const {
    equal->MarkGraphNode();
    return equal(vid, other->vid) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(vid);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.Var";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  static constexpr const uint32_t _type_child_slots = 1;
  TVM_DECLARE_BASE_OBJECT_INFO(VarNode, LeafExprNode);
};
 
class Var : public LeafExpr {
 public:
  TVM_DLL explicit Var(String name_hint, Optional<StructInfo> struct_info_annotation,
                       Span span = Span())
      : Var(Id(name_hint), struct_info_annotation, span) {}
 
  TVM_DLL explicit Var(Id vid, Optional<StructInfo> struct_info_annotation, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(Var, LeafExpr, VarNode);
 
  VarNode* CopyOnWrite();
};
 
class DataflowVarNode : public VarNode {
 public:
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("vid", &vid);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const DataflowVarNode* other, SEqualReducer equal) const {
    equal->MarkGraphNode();
    return equal(vid, other->vid) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(vid);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.DataflowVar";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(DataflowVarNode, VarNode);
};
 
class DataflowVar : public Var {
 public:
  TVM_DLL explicit DataflowVar(String name_hint, Optional<StructInfo> struct_info_annotation,
                               Span span = Span())
      : DataflowVar(Id(name_hint), struct_info_annotation, span) {}
 
  TVM_DLL explicit DataflowVar(Id vid, Optional<StructInfo> struct_info_annotation,
                               Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(DataflowVar, Var, DataflowVarNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(DataflowVarNode);
};
 
class ConstantNode : public LeafExprNode {
 public:
  runtime::NDArray data;
 
  TensorType tensor_type() const;
 
  bool is_scalar() const { return data->ndim == 0; }
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("data", &data);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const ConstantNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from data.
    return equal(data, other->data) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(data);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.Constant";
  TVM_DECLARE_FINAL_OBJECT_INFO(ConstantNode, LeafExprNode);
};
 
class Constant : public LeafExpr {
 public:
  TVM_DLL explicit Constant(runtime::NDArray data,
                            Optional<StructInfo> struct_info_annotation = NullOpt,
                            Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(Constant, LeafExpr, ConstantNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(ConstantNode);
};
 
class PrimValueNode : public LeafExprNode {
 public:
  PrimExpr value;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("value", &value);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const PrimValueNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from data.
    return equal(value, other->value);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(value); }
 
  static constexpr const char* _type_key = "relax.expr.PrimValue";
  TVM_DECLARE_FINAL_OBJECT_INFO(PrimValueNode, LeafExprNode);
};
 
class PrimValue : public LeafExpr {
 public:
  TVM_DLL explicit PrimValue(PrimExpr value, Span span = Span());
 
  TVM_DLL static PrimValue Int64(int64_t value, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(PrimValue, LeafExpr, PrimValueNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(PrimValueNode);
};
 
class StringImmNode : public LeafExprNode {
 public:
  String value;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("value", &value);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const StringImmNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from data.
    return equal(value, other->value);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(value); }
 
  static constexpr const char* _type_key = "relax.expr.StringImm";
  TVM_DECLARE_FINAL_OBJECT_INFO(StringImmNode, LeafExprNode);
};
 
class StringImm : public LeafExpr {
 public:
  TVM_DLL explicit StringImm(String value, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(StringImm, LeafExpr, StringImmNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(StringImmNode);
};
 
class DataTypeImmNode : public LeafExprNode {
 public:
  DataType value;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("value", &value);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const DataTypeImmNode* other, SEqualReducer equal) const {
    // struct info can be deterministically derived from data.
    return equal(value, other->value);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(value); }
 
  static constexpr const char* _type_key = "relax.expr.DataTypeImm";
  TVM_DECLARE_FINAL_OBJECT_INFO(DataTypeImmNode, LeafExprNode);
};
 
class DataTypeImm : public LeafExpr {
 public:
  TVM_DLL explicit DataTypeImm(DataType value, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(DataTypeImm, LeafExpr, DataTypeImmNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(DataTypeImmNode);
};
 
class BindingNode : public Object {
 public:
  Var var;
  mutable Span span;
 
  static constexpr const char* _type_key = "relax.expr.Binding";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_BASE_OBJECT_INFO(BindingNode, Object);
};
 
class Binding : public ObjectRef {
 protected:
  Binding() = default;
 
 public:
  explicit Binding(ObjectPtr<Object> n) : ObjectRef(n) {}
  TVM_DEFINE_DEFAULT_COPY_MOVE_AND_ASSIGN(Binding);
  const BindingNode* operator->() const { return static_cast<const BindingNode*>(data_.get()); }
  const BindingNode* get() const { return operator->(); }
  using ContainerType = BindingNode;
};
 
class MatchCastNode : public BindingNode {
 public:
  Expr value;
  StructInfo struct_info;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("var", &var);
    v->Visit("value", &value);
    v->Visit("struct_info", &struct_info);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const MatchCastNode* other, SEqualReducer equal) const;
  void SHashReduce(SHashReducer hash_reduce) const;
 
  static constexpr const char* _type_key = "relax.expr.MatchCast";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(MatchCastNode, BindingNode);
};
 
class MatchCast : public Binding {
 public:
  TVM_DLL explicit MatchCast(Var var, Expr value, StructInfo struct_info, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(MatchCast, Binding, MatchCastNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(MatchCastNode);
};
 
class VarBindingNode : public BindingNode {
 public:
  Expr value;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("var", &var);
    v->Visit("value", &value);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const VarBindingNode* other, SEqualReducer equal) const;
  void SHashReduce(SHashReducer hash_reduce) const;
 
  static constexpr const char* _type_key = "relax.expr.VarBinding";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(VarBindingNode, BindingNode);
};
 
class VarBinding : public Binding {
 public:
  TVM_DLL explicit VarBinding(Var var, Expr value, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(VarBinding, Binding, VarBindingNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(VarBindingNode);
};
 
class BindingBlockNode : public Object {
 public:
  mutable Span span;
  Array<Binding> bindings;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("span", &span);
    v->Visit("bindings", &bindings);
  }
 
  bool SEqualReduce(const BindingBlockNode* other, SEqualReducer equal) const {
    return equal(bindings, other->bindings);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(bindings); }
 
  static constexpr const char* _type_key = "relax.expr.BindingBlock";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_BASE_OBJECT_INFO(BindingBlockNode, Object);
};
 
class BindingBlock : public ObjectRef {
 public:
  TVM_DLL explicit BindingBlock(Array<Binding> bindings, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(BindingBlock, ObjectRef, BindingBlockNode);
 
  BindingBlockNode* CopyOnWrite();
};
 
class DataflowBlockNode : public BindingBlockNode {
 public:
  bool SEqualReduce(const DataflowBlockNode* other, SEqualReducer equal) const {
    return equal(bindings, other->bindings);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const { hash_reduce(bindings); }
 
  static constexpr const char* _type_key = "relax.expr.DataflowBlock";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(DataflowBlockNode, BindingBlockNode);
};
 
class DataflowBlock : public BindingBlock {
 public:
  TVM_DLL explicit DataflowBlock(Array<Binding> bindings, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(DataflowBlock, BindingBlock, DataflowBlockNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(DataflowBlockNode);
};
 
class SeqExprNode : public ExprNode {
 public:
  Array<BindingBlock> blocks;
  Expr body;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("blocks", &blocks);
    v->Visit("body", &body);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const SeqExprNode* other, SEqualReducer equal) const {
    return equal(blocks, other->blocks) && equal(body, other->body) &&
           equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(blocks);
    hash_reduce(body);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.SeqExpr";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(SeqExprNode, ExprNode);
};
 
class SeqExpr : public Expr {
 public:
  /* \brief Implicit conversion constructor
   *
   * Relax nodes that introduce a new scope (e.g. `relax::Function`)
   * are required to be held as SeqExpr.  This implicit conversion
   * provides allows callsites to use these member variables when the
   * C++ compile-time type is a `relax::Expr`.  For example,
   * a transform may use `func.CopyOnWrite()->body = expr;`.
   *
   * If the expression is already a `relax::SeqExpr`, the same
   * underlying `relax::SeqExprNode` is used, and no copies are made.
   */
  TVM_DLL SeqExpr(Expr body);  // NOLINT(*)
 
  TVM_DLL explicit SeqExpr(Array<BindingBlock> blocks, Expr body, Span span = Span());
  TVM_DEFINE_OBJECT_REF_METHODS(SeqExpr, Expr, SeqExprNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(SeqExprNode);
};
 
class IfNode : public ExprNode {
 public:
  Expr cond;
  SeqExpr true_branch;
  SeqExpr false_branch;
 
  void VisitAttrs(tvm::AttrVisitor* v) {
    v->Visit("cond", &cond);
    v->Visit("true_branch", &true_branch);
    v->Visit("false_branch", &false_branch);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const IfNode* other, SEqualReducer equal) const {
    equal->MarkGraphNode();
    return equal(cond, other->cond) && equal(true_branch, other->true_branch) &&
           equal(false_branch, other->false_branch) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce->MarkGraphNode();
    hash_reduce(cond);
    hash_reduce(true_branch);
    hash_reduce(false_branch);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.If";
  TVM_DECLARE_FINAL_OBJECT_INFO(IfNode, ExprNode);
};
 
class If : public Expr {
 public:
  TVM_DLL If(Expr cond, Expr true_branch, Expr false_branch, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(If, Expr, IfNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(IfNode);
};
 
If WithFields(If if_expr, Optional<Expr> opt_cond = Optional<Expr>(),
              Optional<Expr> opt_true_branch = Optional<Expr>(),
              Optional<Expr> opt_false_branch = Optional<Expr>(),
              Optional<Span> opt_span = Optional<Span>());
 
class FunctionNode : public BaseFuncNode {
 public:
  Array<Var> params;
  SeqExpr body;
  StructInfo ret_struct_info;
  bool is_pure;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("params", &params);
    v->Visit("body", &body);
    v->Visit("is_pure", &is_pure);
    v->Visit("ret_struct_info", &ret_struct_info);
    v->Visit("attrs", &attrs);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const FunctionNode* other, SEqualReducer equal) const {
    equal->MarkGraphNode();
    return equal.DefEqual(params, other->params) && equal(body, other->body) &&
           equal(ret_struct_info, other->ret_struct_info) && equal(is_pure, other->is_pure) &&
           equal(attrs, other->attrs) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce->MarkGraphNode();
    hash_reduce.DefHash(params);
    hash_reduce(body);
    hash_reduce(ret_struct_info);
    hash_reduce(is_pure);
    hash_reduce(attrs);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.Function";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(FunctionNode, BaseFuncNode);
};
 
class Function : public BaseFunc {
 public:
  TVM_DLL explicit Function(Array<Var> params, Expr body, Optional<StructInfo> ret_struct_info,
                            bool is_pure = true, DictAttrs attrs = DictAttrs(), Span span = Span());
 
  TVM_DLL static Function CreateEmpty(Array<Var> params, StructInfo ret_struct_info,
                                      bool is_pure = true, DictAttrs attrs = DictAttrs(),
                                      Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(Function, BaseFunc, FunctionNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(FunctionNode);
};
 
// TODO(@sunggg): Investigate the exact usage of kComposite, kPartitionedFromPattern, and
// kPrimitive.
namespace attr {
constexpr const char* kPrimitive = "Primitive";
constexpr const char* kCodegen = "Codegen";
constexpr const char* kComposite = "Composite";
constexpr const char* kPartitionedFromPattern = "PartitionedFromPattern";
constexpr const char* kWorkspaceSize = "WorkspaceSize";
 
// Note: in the future, we prefer snake_case instead of CamelCase for attributes.
// Past ones will be kept for backwards compatibility.
constexpr const char* kForcePure = "relax.force_pure";
 
constexpr const char* kNumInput = "num_input";
}  // namespace attr
 
class ExternFuncNode : public BaseFuncNode {
 public:
  String global_symbol;
 
  void VisitAttrs(AttrVisitor* v) {
    v->Visit("global_symbol", &global_symbol);
    v->Visit("struct_info_", &struct_info_);
    v->Visit("_checked_type_", &checked_type_);
    v->Visit("span", &span);
  }
 
  bool SEqualReduce(const ExternFuncNode* other, SEqualReducer equal) const {
    return equal(global_symbol, other->global_symbol) && equal(struct_info_, other->struct_info_);
  }
 
  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce(global_symbol);
    hash_reduce(struct_info_);
  }
 
  static constexpr const char* _type_key = "relax.expr.ExternFunc";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(ExternFuncNode, BaseFuncNode);
};
 
class ExternFunc : public BaseFunc {
 public:
  TVM_DLL ExternFunc(String global_symbol, Span span = Span());
  TVM_DLL ExternFunc(String global_symbol, StructInfo struct_info, Span span = Span());
 
  TVM_DEFINE_OBJECT_REF_METHODS(ExternFunc, BaseFunc, ExternFuncNode);
  TVM_DEFINE_OBJECT_REF_COW_METHOD(ExternFuncNode);
};
 
TVM_DLL Expr GetShapeOf(const Expr& expr);
 
}  // namespace relax
}  // namespace tvm
 
/* \brief Allow relax.Var as key in STL tables
 *
 * For most Relax expressions, it would be ambiguous whether the
 * expression should follow reference equality or structural equality.
 * This is not the case for variables, which do not contain nested
 * internal structure, and are frequently used as keys in lookup
 * tables.
 *
 * Providing `std::hash` and `std::equal_to` specializations for
 * `relax::Var` allows it to be used as a key in STL tables.  For
 * `relax::Expr`, the user must specify the type of equality used
 * (e.g. `std::unordered_set<T, StructuralHash, StructuralEqual>` or
 * `std::unordered_set<T, ObjectPtrHash, ObjectPtrEqual>`).
 */
template <>
struct std::hash<tvm::relax::Var> {
  std::size_t operator()(const tvm::relax::Var& var) const {
    return tvm::runtime::ObjectPtrHash()(var);
  }
};
 
template <>
struct std::equal_to<tvm::relax::Var> {
  bool operator()(const tvm::relax::Var& var_a, const tvm::relax::Var& var_b) const {
    return tvm::runtime::ObjectPtrEqual()(var_a, var_b);
  }
};
 
#endif  // TVM_RELAX_EXPR_H_