Merge pull request #16214 from velconia/imperative_infer_var_type

Implement imperative infer var type

paddle/fluid/framework/details/graph_test_base.h

@@ -68,11 +68,11 @@ class SplitOpMaker : public OpProtoAndCheckerMaker {
 
 class DummyVarTypeInference : public VarTypeInference {
  public:
-  void operator()(const OpDesc& op_desc, BlockDesc* block) const override {
-    auto& inputs = op_desc.Input("X");
-    auto type = block->Var(inputs.front())->GetType();
-    auto out_var_name = op_desc.Output("Out").front();
-    block->Var(out_var_name)->SetType(type);
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto& inputs = ctx->Input("X");
+    auto type = ctx->GetType(inputs.front());
+    auto out_var_name = ctx->Output("Out").front();
+    ctx->SetType(out_var_name, type);
   }
 };
 

paddle/fluid/framework/details/op_registry.h

@@ -16,6 +16,8 @@ limitations under the License. */
 
 #include <string>
 #include <tuple>
+#include <unordered_map>
+#include <unordered_set>
 #include <vector>
 #include "paddle/fluid/framework/grad_op_desc_maker.h"
 #include "paddle/fluid/framework/inplace_op_inference.h"
@@ -127,9 +129,9 @@ struct OpInfoFiller<T, kGradOpDescMaker> {
 template <typename T>
 struct OpInfoFiller<T, kVarTypeInference> {
   void operator()(const char* op_type, OpInfo* info) const {
-    info->infer_var_type_ = [](const OpDesc& fwd_op, BlockDesc* block) {
+    info->infer_var_type_ = [](InferVarTypeContext* context) {
       T inference;
-      inference(fwd_op, block);
+      inference(context);
     };
   }
 };

paddle/fluid/framework/ir/graph_test.cc

@@ -43,20 +43,20 @@ class SumOpMaker : public OpProtoAndCheckerMaker {
 
 class SumOpVarTypeInference : public VarTypeInference {
  public:
-  void operator()(const OpDesc &op_desc, BlockDesc *block) const override {
-    auto &inputs = op_desc.Input("X");
+  void operator()(InferVarTypeContext *ctx) const override {
+    auto &inputs = ctx->Input("X");
     auto default_var_type = proto::VarType::SELECTED_ROWS;
 
     bool any_input_is_lod_tensor = std::any_of(
-        inputs.begin(), inputs.end(), [block](const std::string &name) {
-          return block->Var(name)->GetType() == proto::VarType::LOD_TENSOR;
+        inputs.begin(), inputs.end(), [&ctx](const std::string &name) {
+          return ctx->GetType(name) == proto::VarType::LOD_TENSOR;
         });
     if (any_input_is_lod_tensor) {
       default_var_type = proto::VarType::LOD_TENSOR;
     }
 
-    auto out_var_name = op_desc.Output("Out").front();
-    block->Var(out_var_name)->SetType(default_var_type);
+    auto out_var_name = ctx->Output("Out").front();
+    ctx->SetType(out_var_name, default_var_type);
   }
 };
 
@@ -71,7 +71,7 @@ class DummyOpMaker : public OpProtoAndCheckerMaker {
 
 class DummyOpVarTypeInference : public VarTypeInference {
  public:
-  void operator()(const OpDesc &op_desc, BlockDesc *block) const override {}
+  void operator()(framework::InferVarTypeContext *ctx) const override {}
 };
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/op_desc.cc

@@ -24,6 +24,7 @@ limitations under the License. */
 #include "paddle/fluid/framework/operator.h"
 #include "paddle/fluid/framework/program_desc.h"
 #include "paddle/fluid/framework/shape_inference.h"
+#include "paddle/fluid/framework/var_type_inference.h"
 
 namespace paddle {
 namespace framework {
@@ -677,7 +678,8 @@ void OpDesc::InferVarType(BlockDesc *block) const {
   // var type inference. Hence, we don't do any "default" setting here.
   auto &info = OpInfoMap::Instance().Get(this->Type());
   if (info.infer_var_type_) {
-    info.infer_var_type_(*this, block);
+    InferVarTypeContext context(this, block);
+    info.infer_var_type_(&context);
   }
 }
 

paddle/fluid/framework/type_defs.h

@@ -27,6 +27,7 @@ namespace framework {
 class OperatorBase;
 class OpDesc;
 class InferShapeContext;
+class InferVarTypeContext;
 class BlockDesc;
 class Variable;
 
@@ -53,7 +54,7 @@ using GradOpMakerFN = std::function<std::vector<std::unique_ptr<OpDesc>>(
     const std::vector<BlockDesc*>& grad_block)>;
 
 using InferVarTypeFN =
-    std::function<void(const OpDesc& /*op_desc*/, BlockDesc* /*block*/)>;
+    std::function<void(framework::InferVarTypeContext* /*context*/)>;
 
 using InferShapeFN = std::function<void(InferShapeContext*)>;
 

paddle/fluid/framework/var_type_inference.h

@@ -14,6 +14,8 @@ limitations under the License. */
 
 #pragma once
 #include <string>
+#include <unordered_map>
+#include <vector>
 #include "paddle/fluid/framework/block_desc.h"
 #include "paddle/fluid/framework/op_desc.h"
 #include "paddle/fluid/framework/type_defs.h"
@@ -21,26 +23,123 @@ limitations under the License. */
 namespace paddle {
 namespace framework {
 
+class OpDesc;
+class BlockDesc;
+// default infer var type context
+class InferVarTypeContext {
+ public:
+  InferVarTypeContext(const OpDesc* op, BlockDesc* block)
+      : op_(op), block_(block) {}
+
+  virtual ~InferVarTypeContext() {}
+
+  virtual Attribute GetAttr(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(op_);
+    return op_->GetAttr(name);
+  }
+
+  virtual bool HasVar(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindVarRecursive(name) != nullptr;
+  }
+
+  virtual bool HasInput(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(op_);
+    return op_->Inputs().count(name) > 0;
+  }
+
+  virtual bool HasOutput(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(op_);
+    return op_->Outputs().count(name) > 0;
+  }
+
+  virtual const std::vector<std::string>& Input(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(op_);
+    return op_->Input(name);
+  }
+
+  virtual const std::vector<std::string>& Output(
+      const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(op_);
+    return op_->Output(name);
+  }
+
+  virtual proto::VarType::Type GetType(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindRecursiveOrCreateVar(name).GetType();
+  }
+
+  virtual void SetType(const std::string& name, proto::VarType::Type type) {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    block_->FindRecursiveOrCreateVar(name).SetType(type);
+  }
+
+  virtual proto::VarType::Type GetDataType(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindRecursiveOrCreateVar(name).GetDataType();
+  }
+
+  virtual void SetDataType(const std::string& name, proto::VarType::Type type) {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    block_->FindRecursiveOrCreateVar(name).SetDataType(type);
+  }
+
+  virtual std::vector<proto::VarType::Type> GetDataTypes(
+      const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindRecursiveOrCreateVar(name).GetDataTypes();
+  }
+
+  virtual void SetDataTypes(
+      const std::string& name,
+      const std::vector<proto::VarType::Type>& multiple_data_type) {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    block_->FindRecursiveOrCreateVar(name).SetDataTypes(multiple_data_type);
+  }
+
+  virtual std::vector<int64_t> GetShape(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindRecursiveOrCreateVar(name).GetShape();
+  }
+
+  virtual void SetShape(const std::string& name,
+                        const std::vector<int64_t>& dims) {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    block_->FindRecursiveOrCreateVar(name).SetShape(dims);
+  }
+
+  virtual int32_t GetLoDLevel(const std::string& name) const {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    return block_->FindRecursiveOrCreateVar(name).GetLoDLevel();
+  }
+
+  virtual void SetLoDLevel(const std::string& name, int32_t lod_level) {
+    PADDLE_ENFORCE_NOT_NULL(block_);
+    block_->FindRecursiveOrCreateVar(name).SetLoDLevel(lod_level);
+  }
+
+ protected:
+  const OpDesc* op_;
+  BlockDesc* block_;
+};
+
 class VarTypeInference {
  public:
   virtual ~VarTypeInference() {}
-  virtual void operator()(const OpDesc& op_desc, BlockDesc* block) const = 0;
+  virtual void operator()(InferVarTypeContext* context) const = 0;  // NOLINT
 };
 
 class PassInDtypeAndVarTypeToOutput : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const final {
+  void operator()(framework::InferVarTypeContext* ctx) const final {  // NOLINT
     auto in_out_var_names = this->GetInputOutputWithSameType();
 
     for (auto& i_o_n : in_out_var_names) {
-      auto& x_name = op_desc.Input(i_o_n.first).at(0);
-      auto& out_name = op_desc.Output(i_o_n.second).at(0);
+      auto& x_name = ctx->Input(i_o_n.first).at(0);
+      auto& out_name = ctx->Output(i_o_n.second).at(0);
 
-      auto& x = block->FindRecursiveOrCreateVar(x_name);
-      auto& out = block->FindRecursiveOrCreateVar(out_name);
-      out.SetType(x.GetType());
-      out.SetDataType(x.GetDataType());
+      ctx->SetType(out_name, ctx->GetType(x_name));
+      ctx->SetDataType(out_name, ctx->GetDataType(x_name));
     }
   }
 

paddle/fluid/framework/var_type_inference_test.cc

@@ -44,20 +44,20 @@ class SumOpMaker : public OpProtoAndCheckerMaker {
 
 class SumOpVarTypeInference : public VarTypeInference {
  public:
-  void operator()(const OpDesc &op_desc, BlockDesc *block) const override {
-    auto &inputs = op_desc.Input("X");
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto &inputs = ctx->Input("X");
     auto default_var_type = proto::VarType::SELECTED_ROWS;
 
     bool any_input_is_lod_tensor = std::any_of(
-        inputs.begin(), inputs.end(), [block](const std::string &name) {
-          return block->Var(name)->GetType() == proto::VarType::LOD_TENSOR;
+        inputs.begin(), inputs.end(), [&ctx](const std::string &name) {
+          return ctx->GetType(name) == proto::VarType::LOD_TENSOR;
         });
     if (any_input_is_lod_tensor) {
       default_var_type = proto::VarType::LOD_TENSOR;
     }
 
-    auto out_var_name = op_desc.Output("Out").front();
-    block->Var(out_var_name)->SetType(default_var_type);
+    auto out_var_name = ctx->Output("Out").front();
+    ctx->SetType(out_var_name, default_var_type);
   }
 };
 }  // namespace framework

paddle/fluid/imperative/layer.cc

@@ -218,7 +218,7 @@ std::map<std::string, std::vector<VarBase*>> OpBase::ApplyGrad() {
                  "%s has no backward implementation", Type());
 
   VLOG(3) << "apply op grad: " << Type();
-  std::vector<framework::VariableValueMap> tmp_grad_outputs;
+  std::vector<VarBasePtrMap> tmp_grad_outputs;
   if (backward_id_ > 0) {
     VLOG(3) << "py_layer_grad";
     tmp_grad_outputs.resize(1);
@@ -241,26 +241,62 @@ std::map<std::string, std::vector<VarBase*>> OpBase::ApplyGrad() {
         auto& outputs = tmp_grad_outputs[k][it.first];
         outputs.reserve(it.second.size());
         for (size_t i = 0; i < it.second.size(); ++i) {
+          VarBase* origin_grad_var_base = it.second[i];
+
           // Allocate a new variable
-          Variable* tmp_var = new framework::Variable();
-          tmp_var->GetMutable<framework::LoDTensor>();
-          outputs.emplace_back(tmp_var);
+          VarBase* tmp_grad_var_base = new VarBase(
+              string::Sprintf("%s@IGrad", origin_grad_var_base->Name()),
+              origin_grad_var_base->DataType(), origin_grad_var_base->Dims(),
+              place_, true, false);
+          outputs.emplace_back(tmp_grad_var_base);
         }
       }
 
-      // Run grad op
-      framework::RuntimeContext ctx(grad_input_vars_[k], tmp_grad_outputs[k]);
-
       // No need to do compile time infer shape here.
       // grad_op_desc_->InferShape(*block_);
       // grad_op_desc->InferVarType(block_);
 
       std::unique_ptr<framework::OperatorBase> opbase =
           framework::OpRegistry::CreateOp(*grad_op_desc);
+
+      auto& info = framework::OpInfoMap::Instance().Get(grad_op_desc->Type());
+      if (info.infer_var_type_) {
+        RuntimeInferVarTypeContext infer_var_type_ctx(
+            &grad_input_vars_[k], &tmp_grad_outputs[k], &attrs_);
+        info.infer_var_type_(&infer_var_type_ctx);
+      }
+
       framework::OperatorWithKernel* op_kernel =
           dynamic_cast<framework::OperatorWithKernel*>(opbase.get());
       PADDLE_ENFORCE_NOT_NULL(op_kernel, "only support op with kernel");
 
+      // Run grad op
+      framework::VariableValueMap grad_invars_map;
+      framework::VariableValueMap grad_outvars_map;
+
+      for (const auto& it : grad_input_vars_[k]) {
+        auto& grad_invars = grad_invars_map[it.first];
+        grad_invars.reserve(it.second.size());
+        for (const VarBase* grad_inp : it.second) {
+          PADDLE_ENFORCE_NOT_NULL(grad_inp->var_, "op %s input %s nullptr",
+                                  grad_op_desc->Type(), grad_inp->Name());
+
+          grad_invars.emplace_back(grad_inp->var_);
+        }
+      }
+
+      for (const auto& it : tmp_grad_outputs[k]) {
+        auto& grad_outvars = grad_outvars_map[it.first];
+        grad_outvars.reserve(it.second.size());
+        for (VarBase* grad_out : it.second) {
+          PADDLE_ENFORCE_NOT_NULL(grad_out->var_, "op %s output %s nullptr",
+                                  grad_op_desc->Type(), grad_out->Name());
+
+          grad_outvars.emplace_back(grad_out->var_);
+        }
+      }
+
+      framework::RuntimeContext ctx(grad_invars_map, grad_outvars_map);
       framework::Scope scope;
       PreparedOp p = PreparedOp::Prepare(ctx, *op_kernel, place_);
       p.op.RuntimeInferShape(scope, place_, ctx);
@@ -277,8 +313,8 @@ std::map<std::string, std::vector<VarBase*>> OpBase::ApplyGrad() {
       PADDLE_ENFORCE_EQ(outputs.size(), origin_outputs.size());
 
       for (size_t i = 0; i < outputs.size(); ++i) {
-        framework::Variable* grad = outputs[i];
-        framework::Variable* orig_grad = origin_outputs[i];
+        framework::Variable* grad = outputs[i]->var_;
+        framework::Variable* orig_grad = origin_outputs[i]->var_;
         AddTo(grad, orig_grad, place_);
         delete grad;
       }
@@ -326,28 +362,35 @@ void PyLayer::RegisterFunc(int func_id, const py::object& py_func) {
 
 int PyLayer::NumFuncs() { return py_funcs_.size(); }
 
-std::vector<Variable*> PyLayer::Apply(int func_id,
-                                      const std::vector<VarBase*>& inputs) {
-  std::vector<framework::Variable*> invars;
-  for (const VarBase* in : inputs) {
-    invars.push_back(in->var_);
-  }
+std::vector<framework::Variable*> PyLayer::Apply(
+    int func_id, const std::vector<VarBase*>& inputs) {
   PADDLE_ENFORCE(py_funcs_.find(func_id) != py_funcs_.end());
-  return CallPythonFunc(py_funcs_[func_id], invars);
+  return CallPythonFunc(py_funcs_[func_id], inputs);
 }
 
-std::vector<Variable*> PyLayer::ApplyGrad(
-    int func_id, const std::vector<framework::Variable*>& inputs) {
+std::vector<VarBase*> PyLayer::ApplyGrad(int func_id,
+                                         const std::vector<VarBase*>& inputs) {
   PADDLE_ENFORCE(py_funcs_.find(func_id) != py_funcs_.end());
-  return CallPythonFunc(py_funcs_[func_id], inputs);
+  auto rets = CallPythonFunc(py_funcs_[func_id], inputs);
+
+  std::vector<VarBase*> outs;
+  outs.reserve(rets.size());
+  for (size_t i = 0U; i != rets.size(); ++i) {
+    outs.emplace_back(new VarBase(
+        string::Sprintf("%s_out_%d", framework::GradVarName(PyLayer::kFwdOut),
+                        i),
+        rets[i], nullptr, true));
+  }
+
+  return outs;
 }
 
 std::vector<framework::Variable*> PyLayer::CallPythonFunc(
-    const py::object& callable, const std::vector<framework::Variable*>& ins) {
+    const py::object& callable, const std::vector<VarBase*>& ins) {
   py::gil_scoped_acquire guard;
   py::tuple in_args(ins.size());
   for (size_t i = 0; i < ins.size(); ++i) {
-    const framework::LoDTensor& t = ins[i]->Get<framework::LoDTensor>();
+    const framework::LoDTensor& t = ins[i]->var_->Get<framework::LoDTensor>();
     in_args[i] = t.IsInitialized() ? py::cast(t) : py::cast(nullptr);
   }
   VLOG(3) << "pyfunc in " << py::len(in_args);
@@ -357,6 +400,7 @@ std::vector<framework::Variable*> PyLayer::CallPythonFunc(
   auto ret_tuple = py::cast<py::tuple>(ret);
   size_t ret_num = py::len(ret_tuple);
   std::vector<framework::Variable*> outs;
+  outs.reserve(ret_num);
   VLOG(3) << "pyfunc out " << ret_num;
   for (size_t i = 0; i < ret_num; ++i) {
     try {
@@ -367,7 +411,7 @@ std::vector<framework::Variable*> PyLayer::CallPythonFunc(
       auto* tensor = var->GetMutable<framework::LoDTensor>();
       tensor->ShareDataWith(*py_out_tensor);
       tensor->set_lod(py_out_tensor->lod());
-      outs.push_back(var);
+      outs.emplace_back(var);
     } catch (py::cast_error&) {
       PADDLE_THROW("The %d-th output must be LoDTensor", i);
     }

paddle/fluid/imperative/layer.h

@@ -18,14 +18,16 @@
 #include "paddle/fluid/framework/python_headers.h"
 // clang-format on
 
-#include <map>     // NOLINT
-#include <string>  // NOLINT
-#include <vector>  // NOLINT
-#include <memory>  // NOLINT
+#include <map>            // NOLINT
+#include <string>         // NOLINT
+#include <vector>         // NOLINT
+#include <memory>         // NOLINT
+#include <unordered_map>  // NOLINT
 
 #include "paddle/fluid/framework/op_desc.h"
 #include "paddle/fluid/framework/operator.h"
 #include "paddle/fluid/framework/var_desc.h"
+#include "paddle/fluid/framework/var_type_inference.h"
 #include "paddle/fluid/platform/enforce.h"
 #include "paddle/fluid/platform/device_context.h"
 #include "paddle/fluid/operators/math/math_function.h"
@@ -135,13 +137,13 @@ class VarBase {
                 persistable) {}
 
  private:
+  // TODO(minqiyang): need support SelectedRows
   VarBase(const std::string& name, framework::proto::VarType::Type dtype,
           const framework::DDim& shape, const platform::Place& place,
           framework::Variable* var, VarBase* grad, bool stop_gradient,
           bool persistable)
       : name_(name),
-        dtype_(dtype),
-        place_(place),
+        type_(framework::proto::VarType::LOD_TENSOR),
         var_(var),
         grads_(grad),
         stop_gradient_(stop_gradient),
@@ -151,10 +153,12 @@ class VarBase {
         pre_op_out_idx_(-1) {
     if (!var_) {
       var_ = new framework::Variable();
-      auto tensor = var_->GetMutable<framework::LoDTensor>();
-      tensor->Resize(shape);
-      tensor->mutable_data(place_, dtype_);
     }
+    auto tensor = var_->GetMutable<framework::LoDTensor>();
+    tensor->Resize(shape);
+    tensor->mutable_data(place, dtype);
+    VLOG(10) << "create varbase: " << name_ << " type: " << dtype
+             << " place: " << place;
   }
 
  public:
@@ -184,7 +188,23 @@ class VarBase {
     }
   }
 
-  inline framework::proto::VarType::Type DType() const { return dtype_; }
+  inline framework::DDim Dims() const {
+    return var_->Get<framework::LoDTensor>().dims();
+  }
+
+  // data type. e.g.. FP32
+  inline void SetDataType(framework::proto::VarType::Type type) {
+    auto tensor = var_->GetMutable<framework::LoDTensor>();
+    tensor->mutable_data(tensor->place(), type);
+  }
+  inline framework::proto::VarType::Type DataType() const {
+    auto tensor = var_->Get<framework::LoDTensor>();
+    return tensor.type();
+  }
+
+  // tensor type. e.g.. LoDTensor
+  inline void SetType(framework::proto::VarType::Type type) { type_ = type; }
+  inline framework::proto::VarType::Type Type() const { return type_; }
 
   inline void SetStopGradient(bool stop_gradient) {
     stop_gradient_ = stop_gradient;
@@ -238,7 +258,7 @@ class VarBase {
   }
 
   std::string name_;
-  framework::proto::VarType::Type dtype_;
+  framework::proto::VarType::Type type_;
   platform::Place place_;
 
   framework::Variable* var_;
@@ -334,11 +354,13 @@ class PYBIND11_HIDDEN OpBase {
   std::map<std::string, std::vector<int>> pre_ops_out_idx_;
 
   // Inputs to a vector of bwd ops.
-  std::vector<framework::VariableValueMap> grad_input_vars_;
+  std::vector<VarBasePtrMap> grad_input_vars_;
   // Outputs to a vector of bwd ops.
-  std::vector<framework::VariableValueMap> grad_output_vars_;
+  std::vector<VarBasePtrMap> grad_output_vars_;
 
   std::vector<py::object> backward_hooks_;
+
+  framework::AttributeMap attrs_;
 };
 
 class Layer {
@@ -365,12 +387,131 @@ class PyLayer {
   static std::vector<framework::Variable*> Apply(
       int func_id, const std::vector<VarBase*>& inputs);
 
-  static std::vector<framework::Variable*> ApplyGrad(
-      int func_id, const std::vector<framework::Variable*>& inputs);
+  static std::vector<VarBase*> ApplyGrad(int func_id,
+                                         const std::vector<VarBase*>& inputs);
 
  private:
   static std::vector<framework::Variable*> CallPythonFunc(
-      const py::object& callable, const std::vector<framework::Variable*>& ins);
+      const py::object& callable, const std::vector<VarBase*>& ins);
+};
+
+// infer var type context for imperative mode
+class PYBIND11_HIDDEN RuntimeInferVarTypeContext
+    : public framework::InferVarTypeContext {
+ public:
+  RuntimeInferVarTypeContext(const imperative::VarBasePtrMap* inputs,
+                             imperative::VarBasePtrMap* outputs,
+                             const framework::AttributeMap* attrs_map)
+      : InferVarTypeContext(nullptr, nullptr),
+        inputs_(inputs),
+        outputs_(outputs),
+        attrs_(attrs_map),
+        input_names_(),
+        output_names_(),
+        var_set_() {
+    input_names_.reserve(inputs_->size());
+    for (auto& it : *inputs_) {
+      for (imperative::VarBase* var : it.second) {
+        input_names_[it.first].emplace_back(var->Name());
+        var_set_[var->Name()] = var;
+      }
+    }
+
+    output_names_.reserve(outputs_->size());
+    for (auto& it : *outputs_) {
+      for (imperative::VarBase* var : it.second) {
+        output_names_[it.first].emplace_back(var->Name());
+        var_set_[var->Name()] = var;
+      }
+    }
+  }
+
+  virtual ~RuntimeInferVarTypeContext() {}
+
+  framework::Attribute GetAttr(const std::string& name) const override {
+    PADDLE_ENFORCE_NOT_NULL(attrs_);
+    return attrs_->at(name);
+  }
+
+  bool HasVar(const std::string& name) const override {
+    return var_set_.count(name) > 0;
+  }
+
+  bool HasInput(const std::string& name) const override {
+    PADDLE_ENFORCE_NOT_NULL(inputs_);
+    return inputs_->count(name) > 0;
+  }
+
+  bool HasOutput(const std::string& name) const override {
+    PADDLE_ENFORCE_NOT_NULL(outputs_);
+    return outputs_->count(name) > 0;
+  }
+
+  const std::vector<std::string>& Input(
+      const std::string& name) const override {
+    return input_names_.at(name);
+  }
+
+  const std::vector<std::string>& Output(
+      const std::string& name) const override {
+    return output_names_.at(name);
+  }
+
+  framework::proto::VarType::Type GetType(
+      const std::string& name) const override {
+    return var_set_.at(name)->Type();
+  }
+
+  void SetType(const std::string& name,
+               framework::proto::VarType::Type type) override {
+    var_set_[name]->SetType(type);
+  }
+
+  framework::proto::VarType::Type GetDataType(
+      const std::string& name) const override {
+    return var_set_.at(name)->DataType();
+  }
+
+  void SetDataType(const std::string& name,
+                   framework::proto::VarType::Type type) override {
+    var_set_[name]->SetDataType(type);
+  }
+
+  std::vector<framework::proto::VarType::Type> GetDataTypes(
+      const std::string& name) const override {
+    PADDLE_THROW("GetDataTypes is not supported in runtime InferVarType");
+  }
+
+  void SetDataTypes(const std::string& name,
+                    const std::vector<framework::proto::VarType::Type>&
+                        multiple_data_type) override {
+    PADDLE_THROW("SetDataTypes is not supported in runtime InferVarType");
+  }
+
+  std::vector<int64_t> GetShape(const std::string& name) const override {
+    PADDLE_THROW("Do not handle Shape in runtime InferVarType");
+  }
+
+  void SetShape(const std::string& name,
+                const std::vector<int64_t>& dims) override {
+    PADDLE_THROW("Do not handle Shape in runtime InferVarType");
+  }
+
+  int32_t GetLoDLevel(const std::string& name) const override {
+    PADDLE_THROW("Do not handle LoDLevel in runtime InferVarType");
+  }
+
+  void SetLoDLevel(const std::string& name, int32_t lod_level) override {
+    PADDLE_THROW("Do not handle LoDLevel in runtime InferVarType");
+  }
+
+ private:
+  const imperative::VarBasePtrMap* inputs_;
+  imperative::VarBasePtrMap* outputs_;
+  const framework::AttributeMap* attrs_;
+  std::unordered_map<std::string, std::vector<std::string>> input_names_;
+  std::unordered_map<std::string, std::vector<std::string>> output_names_;
+  std::unordered_map<std::string, imperative::VarBase*> var_set_;
 };
 
 }  // namespace imperative

paddle/fluid/imperative/tracer.cc

@@ -19,6 +19,7 @@
 #include <unordered_map>
 #include <unordered_set>
 
+#include "paddle/fluid/framework/var_type_inference.h"
 #include "paddle/fluid/operators/math/math_function.h"
 #include "paddle/fluid/platform/device_context.h"
 #include "paddle/fluid/platform/enforce.h"
@@ -135,7 +136,7 @@ framework::VariableNameMap CreateOutputVarNameMap(
 Tracer::Tracer(framework::BlockDesc* root_block) : root_block_(root_block) {}
 
 std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
-                                    const VarBasePtrMap& outputs,
+                                    VarBasePtrMap* outputs,
                                     framework::AttributeMap attrs_map,
                                     const platform::Place expected_place,
                                     const bool stop_gradient) {
@@ -163,7 +164,7 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
     op->TrackPreOp(it.first, it.second);
   }
 
-  op->output_vars_ = outputs;
+  op->output_vars_ = *outputs;
   for (auto it : op->output_vars_) {
     auto& outvars = outvars_map[it.first];
     const std::vector<VarBase*>& outputs = it.second;
@@ -186,7 +187,7 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
   framework::VariableNameMap invars_name_map =
       CreateInputVarNameMap(op, inputs);
   framework::VariableNameMap outvars_name_map =
-      CreateOutputVarNameMap(op, outputs);
+      CreateOutputVarNameMap(op, *outputs);
 
   auto& info = framework::OpInfoMap::Instance().Get(op->Type());
   if (info.Checker() != nullptr) {
@@ -197,6 +198,11 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
       framework::OpRegistry::CreateOp(op->Type(), invars_name_map,
                                       outvars_name_map, attrs_map);
 
+  if (info.infer_var_type_) {
+    RuntimeInferVarTypeContext infer_var_type_ctx(&inputs, outputs, &attrs_map);
+    info.infer_var_type_(&infer_var_type_ctx);
+  }
+
   // TODO(minqiyang): Support infer var type in imperative mode
   // Run forward op
   VLOG(3) << "tracer running " << op->Type();
@@ -221,6 +227,7 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
     VLOG(5) << "start construct backward op";
 
     // construct grad op descs
+    op->attrs_ = attrs_map;
     std::unique_ptr<framework::OpDesc> fwd_op_desc(new framework::OpDesc(
         op->Type(), invars_name_map, outvars_name_map, attrs_map));
     std::unique_ptr<std::unordered_map<std::string, std::string>> grad_to_var(
@@ -247,12 +254,12 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
             auto fwd_var_it = current_vars_map.find(grad_invar);
             PADDLE_ENFORCE(fwd_var_it != current_vars_map.end());
             // Forward inputs or outputs.
-            grad_in_vars.emplace_back(fwd_var_it->second->var_);
+            grad_in_vars.emplace_back(fwd_var_it->second);
           } else {
             VarBase* var = current_vars_map[var_it->second];
             InitGrad(var, prepared_op.GetDeviceContext());
             // Douts.
-            grad_in_vars.emplace_back(var->grads_->var_);
+            grad_in_vars.emplace_back(var->grads_);
           }
 
           vars_saved_for_backward.insert(it.first);
@@ -269,7 +276,7 @@ std::set<std::string> Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
                          op->Type());
           VarBase* var = current_vars_map[var_it->second];
           InitGrad(var, prepared_op.GetDeviceContext());
-          grad_out_vars.push_back(var->grads_->var_);
+          grad_out_vars.push_back(var->grads_);
         }
       }
     }
@@ -309,23 +316,23 @@ std::vector<VarBase*> Tracer::PyTrace(OpBase* op,
     auto& grad_output_vars =
         op->grad_output_vars_[0][framework::GradVarName(PyLayer::kFwdOut)];
 
-    for (const VarBase* inp : inputs) {
-      grad_input_vars.push_back(inp->var_);
+    for (VarBase* inp : inputs) {
+      grad_input_vars.push_back(inp);
     }
     for (VarBase* out : outputs) {
-      grad_input_vars.push_back(out->var_);
+      grad_input_vars.push_back(out);
     }
 
     // TODO(minqiyang): Add GPU support for PyLayer, only support CPU now
     platform::CPUPlace place;
     for (VarBase* out : outputs) {
       InitGrad(out, platform::DeviceContextPool::Instance().Get(place));
-      grad_input_vars.push_back(out->grads_->var_);
+      grad_input_vars.push_back(out->grads_);
     }
 
     for (VarBase* inp : inputs) {
       InitGrad(inp, platform::DeviceContextPool::Instance().Get(place));
-      grad_output_vars.push_back(inp->grads_->var_);
+      grad_output_vars.push_back(inp->grads_);
     }
   }
   return outputs;

paddle/fluid/imperative/tracer.h

@@ -48,7 +48,7 @@ class Tracer {
   virtual ~Tracer() {}
 
   std::set<std::string> Trace(OpBase* op, const VarBasePtrMap& inputs,
-                              const VarBasePtrMap& outputs,
+                              VarBasePtrMap* outputs,  // NOLINT
                               framework::AttributeMap attrs_map,
                               const platform::Place expected_place,
                               const bool stop_gradient = false);

paddle/fluid/imperative/type_defs.h

@@ -25,6 +25,7 @@ class VarBase;
 class OpBase;
 
 typedef std::map<std::string, std::vector<VarBase*>> VarBasePtrMap;
+typedef std::map<std::string, std::vector<const VarBase*>> ConstVarBasePtrMap;
 typedef std::map<std::string, std::vector<OpBase*>> OpBasePtrMap;
 
 }  // namespace imperative

paddle/fluid/operators/beam_search_decode_op.cc

@@ -178,10 +178,10 @@ Beam Search Decode Operator. This Operator constructs the full hypotheses for
 each source sentence by walking back along the LoDTensorArray Input(ids)
 whose lods can be used to restore the path in the beam search tree.
 
-The Output(SentenceIds) and Output(SentenceScores) separately contain the 
-generated id sequences and the corresponding scores. The shapes and lods of the 
-two LodTensor are same. The lod level is 2 and the two levels separately 
-indicate how many hypotheses each source sentence has and how many ids each 
+The Output(SentenceIds) and Output(SentenceScores) separately contain the
+generated id sequences and the corresponding scores. The shapes and lods of the
+two LodTensor are same. The lod level is 2 and the two levels separately
+indicate how many hypotheses each source sentence has and how many ids each
 hypothesis has.
 )DOC");
   }
@@ -203,15 +203,12 @@ class BeamSearchDecodeInferShape : public framework::InferShapeBase {
 
 class BeamSearchDecodeInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    for (auto& o : op_desc.Output("SentenceIds")) {
-      auto& sentence_ids = block->FindRecursiveOrCreateVar(o);
-      sentence_ids.SetType(framework::proto::VarType::LOD_TENSOR);
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    for (auto& o : ctx->Output("SentenceIds")) {
+      ctx->SetType(o, framework::proto::VarType::LOD_TENSOR);
     }
-    for (auto& o : op_desc.Output("SentenceScores")) {
-      auto& sentence_scores = block->FindRecursiveOrCreateVar(o);
-      sentence_scores.SetType(framework::proto::VarType::LOD_TENSOR);
+    for (auto& o : ctx->Output("SentenceScores")) {
+      ctx->SetType(o, framework::proto::VarType::LOD_TENSOR);
     }
   }
 };

paddle/fluid/operators/beam_search_op.cc

@@ -65,7 +65,7 @@ class BeamSearchOpMaker : public framework::OpProtoAndCheckerMaker {
         .SetDefault(true);
 
     AddComment(R"DOC(
-This operator does the search in beams for one time step. 
+This operator does the search in beams for one time step.
 Specifically, it selects the top-K candidate word ids of current step from
 Input(ids) according to their Input(scores) for all source sentences,
 where K is Attr(beam_size) and Input(ids), Input(scores) are predicted results
@@ -120,15 +120,12 @@ class BeamSearchOp : public framework::OperatorWithKernel {
 
 class BeamSearchInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &o : op_desc.Output("selected_ids")) {
-      auto &selected_ids = block->FindRecursiveOrCreateVar(o);
-      selected_ids.SetType(framework::proto::VarType::LOD_TENSOR);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &o : ctx->Output("selected_ids")) {
+      ctx->SetType(o, framework::proto::VarType::LOD_TENSOR);
     }
-    for (auto &o : op_desc.Output("selected_scores")) {
-      auto &selected_scores = block->FindRecursiveOrCreateVar(o);
-      selected_scores.SetType(framework::proto::VarType::LOD_TENSOR);
+    for (auto &o : ctx->Output("selected_scores")) {
+      ctx->SetType(o, framework::proto::VarType::LOD_TENSOR);
     }
   }
 };

paddle/fluid/operators/controlflow/get_places_op.cc

@@ -93,11 +93,9 @@ execution.
 
 class GetPlacesInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &o_name : op_desc.Output("Out")) {
-      block->FindRecursiveOrCreateVar(o_name).SetType(
-          framework::proto::VarType::PLACE_LIST);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &o_name : ctx->Output("Out")) {
+      ctx->SetType(o_name, framework::proto::VarType::PLACE_LIST);
     }
   }
 };

paddle/fluid/operators/controlflow/tensor_array_read_write_op.cc

@@ -100,16 +100,13 @@ class WriteToArrayInferShape : public framework::InferShapeBase {
 
 class WriteToArrayInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto x_name = op_desc.Input("X")[0];
-    auto out_name = op_desc.Output("Out")[0];
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto x_name = ctx->Input("X")[0];
+    auto out_name = ctx->Output("Out")[0];
     VLOG(10) << "Set Variable " << out_name << " as LOD_TENSOR_ARRAY";
-    auto &out = block->FindRecursiveOrCreateVar(out_name);
-    out.SetType(framework::proto::VarType::LOD_TENSOR_ARRAY);
-    auto *x = block->FindVarRecursive(x_name);
-    if (x != nullptr) {
-      out.SetDataType(x->GetDataType());
+    ctx->SetType(out_name, framework::proto::VarType::LOD_TENSOR_ARRAY);
+    if (ctx->HasVar(x_name)) {
+      ctx->SetDataType(out_name, ctx->GetDataType(x_name));
     }
   }
 };

paddle/fluid/operators/controlflow/while_op.cc

@@ -365,19 +365,16 @@ class WhileGradOpDescMaker : public framework::SingleGradOpDescMaker {
 
 class WhileGradOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto p_names = op_desc.Input(kX);
-    auto pg_ig_names = op_desc.Output(framework::GradVarName(kX));
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto p_names = ctx->Input(kX);
+    auto pg_ig_names = ctx->Output(framework::GradVarName(kX));
 
     for (size_t i = 0; i < p_names.size(); ++i) {
-      auto &p_var = detail::Ref(block->FindVarRecursive(p_names[i]));
-      auto *g_var = block->FindVarRecursive(pg_ig_names[i]);
-      if (g_var != nullptr) {  // Gradient could be @EMPTY@
+      if (ctx->HasVar(pg_ig_names[i])) {
         VLOG(5) << "Setting " << pg_ig_names[i] << " following " << p_names[i]
-                << " type: " << p_var.GetType();
-        g_var->SetType(p_var.GetType());
-        g_var->SetDataType(p_var.GetDataType());
+                << " type: " << ctx->GetType(p_names[i]);
+        ctx->SetType(pg_ig_names[i], ctx->GetType(p_names[i]));
+        ctx->SetDataType(pg_ig_names[i], ctx->GetDataType(p_names[i]));
       }
     }
   }

paddle/fluid/operators/distributed_ops/fake_init_op.cc

@@ -56,8 +56,7 @@ class FakeInitOp : public framework::OperatorBase {
 
 class FakeInitOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {}
+  void operator()(framework::InferVarTypeContext *ctx) const override {}
 };
 
 class FakeInitOpMaker : public framework::OpProtoAndCheckerMaker {

paddle/fluid/operators/distributed_ops/merge_ids_op.cc

@@ -114,11 +114,10 @@ class MergeIdsOp : public framework::OperatorWithKernel {
 
 class MergeIdsOpInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto *input_var = block->Var(op_desc.Input("Ids")[0]);
-    for (auto &out_var : op_desc.Output("Out")) {
-      block->Var(out_var)->SetType(input_var->GetType());
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto input_type = ctx->GetType(ctx->Input("Ids")[0]);
+    for (auto &out_var : ctx->Output("Out")) {
+      ctx->SetType(out_var, input_type);
     }
   }
 };

paddle/fluid/operators/distributed_ops/split_ids_op.cc

@@ -14,6 +14,8 @@ limitations under the License. */
 
 #include "paddle/fluid/operators/distributed_ops/split_ids_op.h"
 
+#include <memory>
+
 namespace paddle {
 namespace operators {
 
@@ -71,11 +73,10 @@ class SplitIdsOp : public framework::OperatorWithKernel {
 
 class SplitIdsOpInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto *input_var = block->Var(op_desc.Input("Ids")[0]);
-    for (auto &out_var : op_desc.Output("Out")) {
-      block->Var(out_var)->SetType(input_var->GetType());
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto input_type = ctx->GetType(ctx->Input("Ids")[0]);
+    for (auto &out_var : ctx->Output("Out")) {
+      ctx->SetType(out_var, input_type);
     }
   }
 };

paddle/fluid/operators/fill_constant_op.cc

@@ -39,12 +39,11 @@ class FillConstantOp : public framework::OperatorWithKernel {
 
 class FillConstantOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
+  void operator()(framework::InferVarTypeContext* ctx) const override {
     auto data_type = static_cast<framework::proto::VarType::Type>(
-        boost::get<int>(op_desc.GetAttr("dtype")));
-    auto& out_var_name = op_desc.Output("Out").front();
-    block->Var(out_var_name)->SetDataType(data_type);
+        boost::get<int>(ctx->GetAttr("dtype")));
+    auto& out_var_name = ctx->Output("Out").front();
+    ctx->SetDataType(out_var_name, data_type);
   }
 };
 

paddle/fluid/operators/fused/fused_embedding_seq_pool_op.cc

@@ -138,22 +138,20 @@ class FusedEmbeddingSeqPoolOpGrad : public framework::OperatorWithKernel {
 class FusedEmbeddingSeqPoolOpGradVarTypeInference
     : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    auto out_var_name = op_desc.Output(framework::GradVarName("W")).front();
-    auto attr = op_desc.GetAttr("is_sparse");
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto out_var_name = ctx->Output(framework::GradVarName("W")).front();
+    auto attr = ctx->GetAttr("is_sparse");
     bool is_sparse = boost::get<bool>(attr);
     if (is_sparse) {
       VLOG(3) << "fused_embedding_seq_pool_grad op "
               << framework::GradVarName("W") << " is set to SelectedRows";
-      block->Var(out_var_name)
-          ->SetType(framework::proto::VarType::SELECTED_ROWS);
+      ctx->SetType(out_var_name, framework::proto::VarType::SELECTED_ROWS);
     } else {
       VLOG(3) << "fused_embedding_seq_pool_grad op "
               << framework::GradVarName("W") << " is set to LoDTensor";
-      block->Var(out_var_name)->SetType(framework::proto::VarType::LOD_TENSOR);
+      ctx->SetType(out_var_name, framework::proto::VarType::LOD_TENSOR);
     }
-    block->Var(out_var_name)->SetDataType(block->Var("W")->GetDataType());
+    ctx->SetDataType(out_var_name, ctx->GetDataType(ctx->Input("W")[0]));
   }
 };
 

paddle/fluid/operators/get_tensor_from_selected_rows_op.cc

@@ -81,15 +81,12 @@ GetTensorFromSelectedRows is used to get the tensor from SelectedRows.
 class GetTensorFromSelectedRowsOpVarTypeInference
     : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const final {
-    auto out_var_name = op_desc.Output("Out").front();
-    auto in_var_name = op_desc.Input("X").front();
-
-    auto out_var = block->FindRecursiveOrCreateVar(out_var_name);
-    auto in_var = block->FindRecursiveOrCreateVar(in_var_name);
-    out_var.SetType(framework::proto::VarType::LOD_TENSOR);
-    out_var.SetDataType(in_var.GetDataType());
+  void operator()(framework::InferVarTypeContext *ctx) const {  // NOLINT
+    auto out_var_name = ctx->Output("Out").front();
+    auto in_var_name = ctx->Input("X").front();
+
+    ctx->SetType(out_var_name, framework::proto::VarType::LOD_TENSOR);
+    ctx->SetDataType(out_var_name, ctx->GetDataType(in_var_name));
   }
 };
 

paddle/fluid/operators/hierarchical_sigmoid_op.cc

@@ -197,38 +197,32 @@ class HierarchicalSigmoidGradOp : public framework::OperatorWithKernel {
 class HierarchicalSigmoidGradOpGradVarTypeInference
     : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    auto w_grad_var_name = op_desc.Output(framework::GradVarName("W")).front();
-    auto bias_grad_var_name_vec =
-        op_desc.Output(framework::GradVarName("Bias"));
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto w_grad_var_name = ctx->Output(framework::GradVarName("W")).front();
+    auto bias_grad_var_name_vec = ctx->Output(framework::GradVarName("Bias"));
     std::string bias_grad_var_name;
     bool hasBias = false;
     if (bias_grad_var_name_vec.size()) {
       hasBias = true;
-      bias_grad_var_name =
-          op_desc.Output(framework::GradVarName("Bias")).front();
+      bias_grad_var_name = ctx->Output(framework::GradVarName("Bias")).front();
     }
-    auto attr = op_desc.GetAttr("is_sparse");
+    auto attr = ctx->GetAttr("is_sparse");
     bool is_sparse = boost::get<bool>(attr);
     if (is_sparse) {
       VLOG(30) << "hierarchical_sigmoid_grad op " << framework::GradVarName("W")
                << " is set to SelectedRows";
-      block->Var(w_grad_var_name)
-          ->SetType(framework::proto::VarType::SELECTED_ROWS);
+      ctx->SetType(w_grad_var_name, framework::proto::VarType::SELECTED_ROWS);
     } else {
       VLOG(30) << "hierarchical_sigmoid_grad op " << framework::GradVarName("W")
                << " is set to LoDTensor";
-      block->Var(w_grad_var_name)
-          ->SetType(framework::proto::VarType::LOD_TENSOR);
+      ctx->SetType(w_grad_var_name, framework::proto::VarType::LOD_TENSOR);
     }
     if (hasBias) {
       VLOG(30) << "hierarchical_sigmoid_grad op "
                << framework::GradVarName("Bias") << " is set to LoDTensor";
-      block->Var(bias_grad_var_name)
-          ->SetType(framework::proto::VarType::LOD_TENSOR);
+      ctx->SetType(bias_grad_var_name, framework::proto::VarType::LOD_TENSOR);
     }
-    block->Var(w_grad_var_name)->SetDataType(block->Var("W")->GetDataType());
+    ctx->SetDataType(w_grad_var_name, ctx->GetDataType(ctx->Input("W")[0]));
   }
 };
 

paddle/fluid/operators/lod_rank_table_op.cc

@@ -64,11 +64,9 @@ class LoDRankTableInferShape : public framework::InferShapeBase {
 
 class LoDRankTableInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &o : op_desc.Output("Out")) {
-      block->FindRecursiveOrCreateVar(o).SetType(
-          framework::proto::VarType::LOD_RANK_TABLE);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &o : ctx->Output("Out")) {
+      ctx->SetType(o, framework::proto::VarType::LOD_RANK_TABLE);
     }
   }
 };

paddle/fluid/operators/lod_tensor_to_array_op.cc

@@ -201,10 +201,9 @@ class LoDTensorToArrayInferShape : public framework::InferShapeBase {
 
 class LoDTensorToArrayInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &out_var : op_desc.Output("Out")) {
-      block->Var(out_var)->SetType(framework::proto::VarType::LOD_TENSOR_ARRAY);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &out_var : ctx->Output("Out")) {
+      ctx->SetType(out_var, framework::proto::VarType::LOD_TENSOR_ARRAY);
     }
   }
 };

paddle/fluid/operators/lookup_table_op.cc

@@ -147,22 +147,20 @@ class LookupTableOpGrad : public framework::OperatorWithKernel {
 
 class LookupTableOpGradVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    auto out_var_name = op_desc.Output(framework::GradVarName("W")).front();
-    auto attr = op_desc.GetAttr("is_sparse");
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto out_var_name = ctx->Output(framework::GradVarName("W")).front();
+    auto attr = ctx->GetAttr("is_sparse");
     bool is_sparse = boost::get<bool>(attr);
     if (is_sparse) {
       VLOG(3) << "lookup_table_grad op " << framework::GradVarName("W")
               << " is set to SelectedRows";
-      block->Var(out_var_name)
-          ->SetType(framework::proto::VarType::SELECTED_ROWS);
+      ctx->SetType(out_var_name, framework::proto::VarType::SELECTED_ROWS);
     } else {
       VLOG(3) << "lookup_table_grad op " << framework::GradVarName("W")
               << " is set to LoDTensor";
-      block->Var(out_var_name)->SetType(framework::proto::VarType::LOD_TENSOR);
+      ctx->SetType(out_var_name, framework::proto::VarType::LOD_TENSOR);
     }
-    block->Var(out_var_name)->SetDataType(block->Var("W")->GetDataType());
+    ctx->SetDataType(out_var_name, ctx->GetDataType(ctx->Input("W")[0]));
   }
 };
 

paddle/fluid/operators/nccl/nccl_op.cc

@@ -60,12 +60,9 @@ class NCCLInitOp : public framework::OperatorBase {
 
 class NCCLInitOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto out_var_name = op_desc.Output("Communicator").front();
-    auto &out_var = block->FindRecursiveOrCreateVar(out_var_name);
-    auto var_type = framework::proto::VarType::RAW;
-    out_var.SetType(var_type);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto out_var_name = ctx->Output("Communicator").front();
+    ctx->SetType(out_var_name, framework::proto::VarType::RAW);
   }
 };
 

paddle/fluid/operators/nce_op.cc

@@ -237,23 +237,21 @@ class NCEOpGrad : public framework::OperatorWithKernel {
 
 class NCEOpGradVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto weight_grad = op_desc.Output(framework::GradVarName("Weight")).front();
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto weight_grad = ctx->Output(framework::GradVarName("Weight")).front();
 
-    auto attr = op_desc.GetAttr("is_sparse");
+    auto attr = ctx->GetAttr("is_sparse");
     bool is_sparse = boost::get<bool>(attr);
     if (is_sparse) {
       VLOG(3) << "nce_op_grad op " << weight_grad << " and "
               << " is set to SelectedRows";
-      block->Var(weight_grad)
-          ->SetType(framework::proto::VarType::SELECTED_ROWS);
+      ctx->SetType(weight_grad, framework::proto::VarType::SELECTED_ROWS);
     } else {
       VLOG(3) << "nce_op_grad op " << weight_grad << " and "
               << " is set to LoDTensor";
-      block->Var(weight_grad)->SetType(framework::proto::VarType::LOD_TENSOR);
+      ctx->SetType(weight_grad, framework::proto::VarType::LOD_TENSOR);
     }
-    block->Var(weight_grad)->SetDataType(block->Var("Input")->GetDataType());
+    ctx->SetDataType(weight_grad, ctx->GetDataType(ctx->Input("Input")[0]));
   }
 };
 

paddle/fluid/operators/ngraph/ngraph_engine_op.cc

@@ -37,8 +37,7 @@ class NgraphEngineOpMaker : public framework::OpProtoAndCheckerMaker {
 
 class NgraphEngineInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {}
+  void operator()(framework::InferVarTypeContext *ctx) const override {}
 };
 
 }  // namespace operators

paddle/fluid/operators/optimizers/lars_momentum_op.cc

@@ -56,9 +56,9 @@ This optimizer use LARS (https://arxiv.org/abs/1708.03888) to optimize each
 weight using a local learning rate:
 
 $$
-local\_lr = \eta  * 
+local\_lr = \eta  *
     \frac{\left \| param \right \|}{\left \| grad \right \| + \beta *\left \| param \right \|} \\
-velocity = mu * velocity + 
+velocity = mu * velocity +
     local\_lr * (grad + \beta * param) \\
 param = param - velocity. \\
 $$
@@ -72,8 +72,7 @@ use L2 regularizers in case of using LARS.
 
 class LarsMomentumOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {}
+  void operator()(framework::InferVarTypeContext* ctx) const override {}
 };
 }  // namespace operators
 }  // namespace paddle

paddle/fluid/operators/optimizers/momentum_op.cc

@@ -21,18 +21,14 @@ using Tensor = framework::Tensor;
 
 class MomentumOpInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    auto input_var = op_desc.Input("Param")[0];
-    for (auto& out_var : op_desc.Output("ParamOut")) {
-      if (block->FindRecursiveOrCreateVar(input_var).GetType() ==
-          framework::proto::VarType::SELECTED_ROWS) {
-        block->FindRecursiveOrCreateVar(out_var).SetType(
-            framework::proto::VarType::SELECTED_ROWS);
-      } else if (block->FindRecursiveOrCreateVar(input_var).GetType() ==
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto& input_var = ctx->Input("Param")[0];
+    for (auto& out_var : ctx->Output("ParamOut")) {
+      if (ctx->GetType(input_var) == framework::proto::VarType::SELECTED_ROWS) {
+        ctx->SetType(out_var, framework::proto::VarType::SELECTED_ROWS);
+      } else if (ctx->GetType(input_var) ==
                  framework::proto::VarType::LOD_TENSOR) {
-        block->FindRecursiveOrCreateVar(out_var).SetType(
-            framework::proto::VarType::LOD_TENSOR);
+        ctx->SetType(out_var, framework::proto::VarType::LOD_TENSOR);
       } else {
         PADDLE_THROW(
             "Only support LodTensor and SelectedRows, Unexpected Input Type.");

paddle/fluid/operators/optimizers/sgd_op.cc

@@ -50,20 +50,18 @@ class SGDOp : public framework::OperatorWithKernel {
 
 class SGDOpInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto input_var_n = op_desc.Input("Param")[0];
-    auto in_var_type = block->FindRecursiveOrCreateVar(input_var_n).GetType();
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto &input_var_n = ctx->Input("Param")[0];
+    auto in_var_type = ctx->GetType(input_var_n);
     PADDLE_ENFORCE(in_var_type == framework::proto::VarType::SELECTED_ROWS ||
                        in_var_type == framework::proto::VarType::LOD_TENSOR,
                    "The input Var's type should be LoDtensor or SelectedRows,"
                    " but the received var(%s)'s type is %s",
                    input_var_n, in_var_type);
 
-    for (auto &out_var_n : op_desc.Output("ParamOut")) {
-      auto &out_var = block->FindRecursiveOrCreateVar(out_var_n);
-      if (out_var.GetType() != in_var_type) {
-        out_var.SetType(in_var_type);
+    for (auto &out_var_n : ctx->Output("ParamOut")) {
+      if (ctx->GetType(out_var_n) != in_var_type) {
+        ctx->SetType(out_var_n, in_var_type);
       }
     }
   }

paddle/fluid/operators/py_func_op.cc

@@ -14,8 +14,11 @@
 
 #include "paddle/fluid/operators/py_func_op.h"
 
+#include <memory>
 #include <set>
 #include <string>
+#include <unordered_set>
+#include <utility>
 #include <vector>
 #include "paddle/fluid/framework/op_registry.h"
 
@@ -91,15 +94,12 @@ static void CallPythonFunc(py::object *callable,
   }
 }
 
-class PyFuncOpVarTypInference : public framework::VarTypeInference {
+class PyFuncOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op,
-                  framework::BlockDesc *block) const override {
-    auto &outs = op.Outputs();
-    bool has_out = (outs.count("Out") > 0 && !outs.at("Out").empty());
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    bool has_out = (ctx->HasOutput("Out") && !ctx->Output("Out").empty());
 
-    auto &ins = op.Inputs();
-    bool has_in = (ins.count("X") > 0 && !ins.at("X").empty());
+    bool has_in = (ctx->HasInput("X") && !ctx->Input("X").empty());
 
     /**
      * X or Out can be empty, so that py_func can be more flexible
@@ -107,8 +107,8 @@ class PyFuncOpVarTypInference : public framework::VarTypeInference {
      */
     PADDLE_ENFORCE(has_in || has_out, "Input(X) or Output(Out) must exist");
 
-    PADDLE_ENFORCE_GE(boost::get<int>(op.GetAttr(kForwardPythonCallableId)), 0,
-                      "Function id cannot be less than 0");
+    PADDLE_ENFORCE_GE(boost::get<int>(ctx->GetAttr(kForwardPythonCallableId)),
+                      0, "Function id cannot be less than 0");
 
     if (!has_out) return;
 
@@ -118,7 +118,7 @@ class PyFuncOpVarTypInference : public framework::VarTypeInference {
      * the corresponding forward variable
      */
     const std::string kGradVarSuffix = framework::kGradVarSuffix;
-    auto &out_var_names = outs.at("Out");
+    auto &out_var_names = ctx->Output("Out");
     for (auto &out_var_name : out_var_names) {
       if (out_var_name == framework::kEmptyVarName ||
           out_var_name.size() < kGradVarSuffix.size()) {
@@ -128,18 +128,17 @@ class PyFuncOpVarTypInference : public framework::VarTypeInference {
       size_t len = out_var_name.size() - kGradVarSuffix.size();
       if (out_var_name.substr(len) == kGradVarSuffix) {
         auto fwd_var_name = out_var_name.substr(0, len);
-        auto *out_var_desc = block->FindVarRecursive(out_var_name);
-        auto *fwd_var_desc = block->FindVarRecursive(fwd_var_name);
-        PADDLE_ENFORCE_NOT_NULL(out_var_desc, "Backward variable %s not found",
-                                out_var_name);
-        PADDLE_ENFORCE_NOT_NULL(fwd_var_desc, "Forward variable %s not found",
-                                fwd_var_name);
+        PADDLE_ENFORCE(ctx->HasVar(out_var_name),
+                       "Backward variable %s not found", out_var_name);
+        PADDLE_ENFORCE(ctx->HasVar(fwd_var_name),
+                       "Backward variable %s not found", fwd_var_name);
         VLOG(10) << "Infer var_desc of Output(" << out_var_name << ") as Input("
                  << fwd_var_name << ")";
-        out_var_desc->SetShape(fwd_var_desc->GetShape());
-        out_var_desc->SetDataType(fwd_var_desc->GetDataType());
-        out_var_desc->SetLoDLevel(fwd_var_desc->GetLoDLevel());
-        out_var_desc->SetType(fwd_var_desc->GetType());
+
+        ctx->SetShape(out_var_name, ctx->GetShape(fwd_var_name));
+        ctx->SetDataType(out_var_name, ctx->GetDataType(fwd_var_name));
+        ctx->SetLoDLevel(out_var_name, ctx->GetLoDLevel(fwd_var_name));
+        ctx->SetType(out_var_name, ctx->GetType(fwd_var_name));
       }
     }
   }
@@ -309,5 +308,5 @@ class PyFuncOp : public framework::OperatorBase {
 namespace ops = paddle::operators;
 
 REGISTER_OPERATOR(py_func, ops::PyFuncOp, ops::PyFuncOpMaker,
-                  ops::PyFuncOpVarTypInference, ops::PyFuncOpShapeInference,
+                  ops::PyFuncOpVarTypeInference, ops::PyFuncOpShapeInference,
                   ops::PyFuncOpGradDescMaker);

paddle/fluid/operators/reader/create_custom_reader_op.cc

@@ -85,10 +85,10 @@ class CreateCustomReaderOpMaker : public DecoratedReaderMakerBase {
     AddComment(R"DOC(
       CreateCustomReader Operator
 
-      A custom reader can be used for input data preprocessing. 
-      A custom reader holds its own sub-block, which will be executed in CPU 
-      in its 'ReadNext()' function. Users can configurate their own 
-      preprocessing pipelines by inserting operators into custom reader's 
+      A custom reader can be used for input data preprocessing.
+      A custom reader holds its own sub-block, which will be executed in CPU
+      in its 'ReadNext()' function. Users can configurate their own
+      preprocessing pipelines by inserting operators into custom reader's
       sub-block.
     )DOC");
   }
@@ -123,23 +123,22 @@ class CustomReaderInferShape : public framework::InferShapeBase {
 
 class CustomReaderInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    framework::VarDesc* out_reader = block->FindVar(op_desc.Output("Out")[0]);
-    PADDLE_ENFORCE_NOT_NULL(out_reader);
-    out_reader->SetType(framework::proto::VarType::READER);
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto& out_var_name = ctx->Output("Out")[0];
+    PADDLE_ENFORCE(ctx->HasVar(out_var_name));
+    ctx->SetType(out_var_name, framework::proto::VarType::READER);
 
     auto sink_var_names =
-        boost::get<std::vector<std::string>>(op_desc.GetAttr("sink_var_names"));
+        boost::get<std::vector<std::string>>(ctx->GetAttr("sink_var_names"));
     const auto* sub_block =
-        boost::get<framework::BlockDesc*>(op_desc.GetAttr("sub_block"));
+        boost::get<framework::BlockDesc*>(ctx->GetAttr("sub_block"));
     std::vector<framework::proto::VarType::Type> res_data_types;
     for (const std::string& var_name : sink_var_names) {
       framework::VarDesc* var = sub_block->FindVar(var_name);
       PADDLE_ENFORCE_NOT_NULL(var);
       res_data_types.emplace_back(var->GetDataType());
     }
-    out_reader->SetDataTypes(res_data_types);
+    ctx->SetDataTypes(out_var_name, res_data_types);
   }
 };
 

paddle/fluid/operators/reader/read_op.cc

@@ -51,19 +51,16 @@ class ReadInferShape : public framework::InferShapeBase {
 
 class ReadInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    bool infer_out = boost::get<bool>(op_desc.GetAttr("infer_out"));
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    bool infer_out = boost::get<bool>(ctx->GetAttr("infer_out"));
     if (infer_out) {
-      std::string reader_name = op_desc.Input("Reader")[0];
-      std::vector<std::string> out_names = op_desc.Output("Out");
-      framework::VarDesc* reader = block->FindVarRecursive(reader_name);
-      auto dtypes = reader->GetDataTypes();
+      std::string reader_name = ctx->Input("Reader")[0];
+      std::vector<std::string> out_names = ctx->Output("Out");
+      auto dtypes = ctx->GetDataTypes(reader_name);
       PADDLE_ENFORCE_EQ(dtypes.size(), out_names.size());
       for (size_t i = 0; i < dtypes.size(); ++i) {
-        framework::VarDesc& out = block->FindRecursiveOrCreateVar(out_names[i]);
-        out.SetType(framework::proto::VarType::LOD_TENSOR);
-        out.SetDataType(dtypes[i]);
+        ctx->SetType(out_names[i], framework::proto::VarType::LOD_TENSOR);
+        ctx->SetDataType(out_names[i], dtypes[i]);
       }
     }
   }

paddle/fluid/operators/reader/reader_op_registry.cc

@@ -98,11 +98,10 @@ void FileReaderInferShape::operator()(framework::InferShapeContext* ctx) const {
   }
 }
 
-void FileReaderInferVarType::operator()(const framework::OpDesc& op_desc,
-                                        framework::BlockDesc* block) const {
-  std::string reader_name = op_desc.Output("Out")[0];
-  framework::VarDesc* reader = block->FindVarRecursive(reader_name);
-  reader->SetType(framework::proto::VarType::READER);
+void FileReaderInferVarType::operator()(
+    framework::InferVarTypeContext* ctx) const {
+  std::string reader_name = ctx->Output("Out")[0];
+  ctx->SetType(reader_name, framework::proto::VarType::READER);
 }
 
 void DecoratedReaderInferShape::operator()(
@@ -125,13 +124,11 @@ void DecoratedReaderInferShape::operator()(
 }
 
 void DecoratedReaderInferVarType::operator()(
-    const framework::OpDesc& op_desc, framework::BlockDesc* block) const {
-  std::string in_reader_name = op_desc.Input("UnderlyingReader")[0];
-  framework::VarDesc* in_reader = block->FindVarRecursive(in_reader_name);
-  std::string out_reader_name = op_desc.Output("Out")[0];
-  framework::VarDesc* out_reader = block->FindVarRecursive(out_reader_name);
-  out_reader->SetType(framework::proto::VarType::READER);
-  out_reader->SetDataTypes(in_reader->GetDataTypes());
+    framework::InferVarTypeContext* ctx) const {
+  const std::string& in_reader_name = ctx->Input("UnderlyingReader")[0];
+  const std::string& out_reader_name = ctx->Output("Out")[0];
+  ctx->SetType(out_reader_name, framework::proto::VarType::READER);
+  ctx->SetDataTypes(out_reader_name, ctx->GetDataTypes(in_reader_name));
 }
 
 void DecoratedReaderMakerBase::Make() {

paddle/fluid/operators/reader/reader_op_registry.h

@@ -14,7 +14,9 @@
 
 #pragma once
 
+#include <memory>
 #include <string>
+#include <unordered_map>
 #include <vector>
 #include "paddle/fluid/framework/op_registry.h"
 #include "paddle/fluid/framework/reader.h"
@@ -59,8 +61,7 @@ class FileReaderInferShape : public framework::InferShapeBase {
 
 class FileReaderInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override;
+  void operator()(framework::InferVarTypeContext* ctx) const override;
 };
 
 // general infershape for decorated reader
@@ -72,8 +73,7 @@ class DecoratedReaderInferShape : public framework::InferShapeBase {
 // general var type inference for decorated reader
 class DecoratedReaderInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override;
+  void operator()(framework::InferVarTypeContext* ctx) const override;
 };
 
 class DecoratedReaderMakerBase : public framework::OpProtoAndCheckerMaker {

paddle/fluid/operators/save_op.cc

@@ -159,12 +159,9 @@ This operator will serialize and write LoDTensor / SelectedRows variable to file
 
 class SaveOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto out_var_name = op_desc.Output(LOOKUP_TABLE_PATH).front();
-    auto &out_var = block->FindRecursiveOrCreateVar(out_var_name);
-    auto var_type = framework::proto::VarType::RAW;
-    out_var.SetType(var_type);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto out_var_name = ctx->Output(LOOKUP_TABLE_PATH).front();
+    ctx->SetType(out_var_name, framework::proto::VarType::RAW);
   }
 };
 

paddle/fluid/operators/scale_op.cc

@@ -14,6 +14,7 @@ limitations under the License. */
 
 #include "paddle/fluid/operators/scale_op.h"
 
+#include <memory>
 #include <string>
 
 #include "paddle/fluid/operators/detail/safe_ref.h"
@@ -69,17 +70,13 @@ $$Out = scale*(X + bias)$$
 
 class ScaleOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto &in_var_name = op_desc.Input("X").front();
-    auto &in_var = detail::Ref(block->FindVarRecursive(in_var_name));
-
-    auto out_var_name = op_desc.Output("Out").front();
-    auto *out_var = block->FindVarRecursive(out_var_name);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto &in_var_name = ctx->Input("X").front();
+    auto out_var_name = ctx->Output("Out").front();
 
     if (in_var_name != out_var_name) {
-      out_var->SetType(in_var.GetType());
-      out_var->SetDataType(in_var.GetDataType());
+      ctx->SetType(out_var_name, ctx->GetType(in_var_name));
+      ctx->SetDataType(out_var_name, ctx->GetDataType(in_var_name));
     }
   }
 };

paddle/fluid/operators/split_selected_rows_op.cc

@@ -14,6 +14,8 @@ limitations under the License. */
 
 #include "paddle/fluid/operators/split_selected_rows_op.h"
 
+#include <memory>
+
 namespace paddle {
 namespace operators {
 
@@ -60,10 +62,9 @@ class SplitSelectedRowsOp : public framework::OperatorWithKernel {
 
 class SplitSelectedRowsOpInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &out_var : op_desc.Output("Out")) {
-      block->Var(out_var)->SetType(framework::proto::VarType::SELECTED_ROWS);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &out_var : ctx->Output("Out")) {
+      ctx->SetType(out_var, framework::proto::VarType::SELECTED_ROWS);
     }
   }
 };

paddle/fluid/operators/sum_op.cc

@@ -12,6 +12,7 @@ limitations under the License. */
 #include "paddle/fluid/operators/sum_op.h"
 
 #include <algorithm>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -159,24 +160,20 @@ the LoD information with the first input.
 
 class SumOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc& op_desc,
-                  framework::BlockDesc* block) const override {
-    auto& inputs = op_desc.Input("X");
+  void operator()(framework::InferVarTypeContext* ctx) const override {
+    auto& inputs = ctx->Input("X");
     auto var_type = framework::proto::VarType::SELECTED_ROWS;
-    for (auto& name : op_desc.Input("X")) {
-      VLOG(10) << name << " "
-               << block->FindRecursiveOrCreateVar(name).GetType();
+    for (auto& name : ctx->Input("X")) {
+      VLOG(10) << name << " " << ctx->GetType(name);
     }
 
     bool any_input_is_lod_tensor = std::any_of(
-        inputs.begin(), inputs.end(), [block](const std::string& name) {
-          return block->FindRecursiveOrCreateVar(name).GetType() ==
-                 framework::proto::VarType::LOD_TENSOR;
+        inputs.begin(), inputs.end(), [ctx](const std::string& name) {
+          return ctx->GetType(name) == framework::proto::VarType::LOD_TENSOR;
         });
 
-    auto is_tensor_array = [block](const std::string& name) {
-      return block->FindRecursiveOrCreateVar(name).GetType() ==
-             framework::proto::VarType::LOD_TENSOR_ARRAY;
+    auto is_tensor_array = [ctx](const std::string& name) {
+      return ctx->GetType(name) == framework::proto::VarType::LOD_TENSOR_ARRAY;
     };
 
     bool any_input_is_tensor_array =
@@ -188,8 +185,7 @@ class SumOpVarTypeInference : public framework::VarTypeInference {
       if (!all_inputs_are_tensor_array) {
         std::ostringstream os;
         for (auto& each : inputs) {
-          os << "    " << each << " type is "
-             << block->FindRecursiveOrCreateVar(each).GetType() << "\n";
+          os << "    " << each << " type is " << ctx->GetType(each) << "\n";
         }
         PADDLE_ENFORCE(all_inputs_are_tensor_array,
                        "Not all inputs are tensor array:\n%s", os.str());
@@ -199,11 +195,9 @@ class SumOpVarTypeInference : public framework::VarTypeInference {
       var_type = framework::proto::VarType::LOD_TENSOR;
     }
 
-    auto out_var_name = op_desc.Output("Out").front();
-    auto& out_var = block->FindRecursiveOrCreateVar(out_var_name);
-    out_var.SetType(var_type);
-    auto& in_var = detail::Ref(block->FindVarRecursive(inputs.front()));
-    out_var.SetDataType(in_var.GetDataType());
+    auto out_var_name = ctx->Output("Out").front();
+    ctx->SetType(out_var_name, var_type);
+    ctx->SetDataType(out_var_name, ctx->GetDataType(inputs.front()));
   }
 };
 

paddle/fluid/operators/tensor_array_to_tensor_op.cc

@@ -177,10 +177,9 @@ class LoDTensorArray2TensorGradInferShape : public framework::InferShapeBase {
 class LoDTensorArray2TensorGradInferVarType
     : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    for (auto &out_var : op_desc.Output(framework::GradVarName("X"))) {
-      block->Var(out_var)->SetType(framework::proto::VarType::LOD_TENSOR_ARRAY);
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    for (auto &out_var : ctx->Output(framework::GradVarName("X"))) {
+      ctx->SetType(out_var, framework::proto::VarType::LOD_TENSOR_ARRAY);
     }
   }
 };

paddle/fluid/operators/tensorrt/tensorrt_engine_op.cc

@@ -46,8 +46,7 @@ class TensorRTEngineOpMaker : public framework::OpProtoAndCheckerMaker {
 
 class TensorRTEngineInferVarType : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {}
+  void operator()(framework::InferVarTypeContext *ctx) const override {}
 };
 
 }  // namespace operators

paddle/fluid/operators/uniform_random_op.cc

@@ -112,17 +112,16 @@ uniform distribution. The random result is in set [min, max].
 
 class UniformRandomOpVarTypeInference : public framework::VarTypeInference {
  public:
-  void operator()(const framework::OpDesc &op_desc,
-                  framework::BlockDesc *block) const override {
-    auto out_var_name = op_desc.Output("Out").front();
+  void operator()(framework::InferVarTypeContext *ctx) const override {
+    auto out_var_name = ctx->Output("Out").front();
     auto var_data_type = static_cast<framework::proto::VarType::Type>(
-        boost::get<int>(op_desc.GetAttr("dtype")));
+        boost::get<int>(ctx->GetAttr("dtype")));
 
-    auto out_var = block->FindRecursiveOrCreateVar(out_var_name);
-    if (out_var.GetType() != framework::proto::VarType::SELECTED_ROWS) {
-      out_var.SetType(framework::proto::VarType::LOD_TENSOR);
+    if (ctx->GetType(out_var_name) !=
+        framework::proto::VarType::SELECTED_ROWS) {
+      ctx->SetType(out_var_name, framework::proto::VarType::LOD_TENSOR);
     }
-    out_var.SetDataType(var_data_type);
+    ctx->SetDataType(out_var_name, var_data_type);
   }
 };
 

paddle/fluid/pybind/imperative.cc

@@ -38,7 +38,7 @@ void BindTracer(pybind11::module* m) {
       .def("trace",
            [](imperative::Tracer& self, imperative::OpBase* op,
               const imperative::VarBasePtrMap& inputs,
-              const imperative::VarBasePtrMap& outputs,
+              imperative::VarBasePtrMap* outputs,
               framework::AttributeMap attrs_map,
               const platform::CPUPlace expected_place,
               const bool stop_gradient = false) {
@@ -49,7 +49,7 @@ void BindTracer(pybind11::module* m) {
       .def("trace",
            [](imperative::Tracer& self, imperative::OpBase* op,
               const imperative::VarBasePtrMap& inputs,
-              const imperative::VarBasePtrMap& outputs,
+              imperative::VarBasePtrMap* outputs,
               framework::AttributeMap attrs_map,
               const platform::CUDAPlace expected_place,
               const bool stop_gradient = false) {

paddle/fluid/pybind/pybind.cc

@@ -200,7 +200,7 @@ PYBIND11_MODULE(core, m) {
       .def_property("name", &imperative::VarBase::Name,
                     &imperative::VarBase::SetName)
       .def_property_readonly("shape", &imperative::VarBase::Shape)
-      .def_property_readonly("dtype", &imperative::VarBase::DType)
+      .def_property_readonly("dtype", &imperative::VarBase::DataType)
       .def_property("persistable", &imperative::VarBase::IsPersistable,
                     &imperative::VarBase::SetPersistable)
       .def_property("stop_gradient", &imperative::VarBase::IsStopGradient,