add light api for mobile

paddle/fluid/lite/api/CMakeLists.txt

+set(cxx_api_lite_deps scope_lite host_kernels ops_lite optimizer_lite target_wrapper_host kernels_cuda optimizer_lite model_parser_lite)
 if(LITE_WITH_CUDA)
-    cc_library(cxx_api_lite_cuda SRCS cxx_api.cc DEPS scope_lite host_kernels ops_lite optimizer_lite target_wrapper_host target_wrapper_cuda kernels_cuda optimizer_lite)
-    nv_test(test_cxx_api_lite_cuda SRCS cxx_api_test.cc DEPS cxx_api_lite_cuda model_parser_lite)
-else()
-    cc_library(cxx_api_lite SRCS cxx_api.cc DEPS scope_lite op_executor_lite host_kernels ops_lite optimizer_lite target_wrapper_host)
-    cc_test(test_cxx_api_lite SRCS cxx_api_test.cc DEPS cxx_api_lite model_parser_lite target_wrapper_host host_kernels)
+    cc_library(cxx_api_lite_cuda SRCS cxx_api.cc DEPS ${cxx_api_lite_deps} target_wrapper_cuda)
+    nv_test(test_cxx_api_lite_cuda SRCS cxx_api_test.cc DEPS cxx_api_lite_cuda)
 endif()
+
+cc_library(cxx_api_lite SRCS cxx_api.cc DEPS ${cxx_api_lite_deps})
+
+set(light_api_deps
+    scope_lite host_kernels ops_lite target_wrapper_host model_parser_lite)
+
+if(LITE_WITH_CUDA)
+    set(light_api_deps ${light_api_deps} target_wrapper_cuda)
+endif()
+
+cc_library(light_api_lite SRCS light_api.cc DEPS ${light_api_deps})
+
+cc_test(test_cxx_api_lite SRCS cxx_api_test.cc DEPS cxx_api_lite model_parser_lite target_wrapper_host host_kernels)
+cc_test(test_light_api SRCS light_api_test.cc DEPS light_api_lite)

paddle/fluid/lite/api/cxx_api.cc

@@ -18,7 +18,7 @@
 namespace paddle {
 namespace lite {
 
-void Predictor::SaveModel(const std::string &dir) {
+void CxxPredictor::SaveModel(const std::string &dir) {
   MkDirRecursively(dir.c_str());
   program_->PersistModel(dir, program_desc_);
 }

paddle/fluid/lite/api/cxx_api.h

@@ -25,9 +25,9 @@ namespace lite {
 
 struct Config {};
 
-class Predictor {
+class CxxPredictor {
  public:
-  Predictor() { scope_ = std::make_shared<Scope>(); }
+  CxxPredictor() { scope_ = std::make_shared<Scope>(); }
 
   void Build(const std::string& model_path, const Place& prefer_place,
              const std::vector<Place>& valid_places) {

paddle/fluid/lite/api/cxx_api_test.cc

@@ -22,7 +22,7 @@ namespace paddle {
 namespace lite {
 
 TEST(CXXApi, test) {
-  lite::Predictor predictor;
+  lite::CxxPredictor predictor;
 #ifndef LITE_WITH_CUDA
   std::vector<Place> valid_places({Place{TARGET(kHost), PRECISION(kFloat)}});
 #else
@@ -60,7 +60,7 @@ TEST(CXXApi, test) {
 }
 
 TEST(CXXApi, save_model) {
-  lite::Predictor predictor;
+  lite::CxxPredictor predictor;
   std::vector<Place> valid_places({Place{TARGET(kHost), PRECISION(kFloat)}});
   predictor.Build("/home/chunwei/project/models/model2",
                   Place{TARGET(kCUDA), PRECISION(kFloat)}, valid_places);

paddle/fluid/lite/api/light_api.cc

+// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed 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.
+
+#include "paddle/fluid/lite/api/light_api.h"

paddle/fluid/lite/api/light_api.h

+// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed 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.
+
+/*
+ * This file implements a light-weight API which can run on mobile. We limit the
+ * dependencies and the runtime computation complexity.
+ */
+#pragma once
+
+#include <string>
+#include <vector>
+#include "paddle/fluid/lite/core/program.h"
+#include "paddle/fluid/lite/core/types.h"
+#include "paddle/fluid/lite/model_parser/model_parser.h"
+#include "paddle/fluid/lite/model_parser/pb/op_desc.h"
+
+namespace paddle {
+namespace lite {
+
+class CxxPredictor {
+ public:
+  CxxPredictor() { scope_ = std::make_shared<Scope>(); }
+
+  void Build(const std::string& model_dir) {
+    framework::proto::ProgramDesc desc;
+    LoadModel(model_dir, scope_.get(), &desc);
+    BuildRuntimeProgram(desc);
+  }
+
+  void Run() { program_->Run(); }
+
+  // Get offset-th col of feed.
+  Tensor* GetInput(size_t offset) {
+    auto* _feed_list = program_->exec_scope()->FindVar("feed");
+    CHECK(_feed_list) << "no feed variable in exec_scope";
+    auto* feed_list = _feed_list->GetMutable<std::vector<Tensor>>();
+    if (offset >= feed_list->size()) {
+      feed_list->resize(offset + 1);
+    }
+    return &feed_list->at(offset);
+  }
+
+  const Tensor* GetOutput(size_t offset) {
+    auto* _fetch_list = program_->exec_scope()->FindVar("fetch");
+    CHECK(_fetch_list) << "no fatch variable in exec_scope";
+    auto& fetch_list = *_fetch_list->GetMutable<std::vector<lite::Tensor>>();
+    CHECK_LT(offset, fetch_list.size()) << "offset " << offset << " overflow";
+    return &fetch_list.at(offset);
+  }
+
+ private:
+  void BuildRuntimeProgram(const framework::proto::ProgramDesc& prog) {
+    std::vector<Instruct> insts;
+    // 1. Create op first
+    Program program(prog, scope_, {});
+
+    // 2. Create Instructs
+
+    // Create the kernels of the target places, and filter out the specific
+    // kernel with the target alias.
+    for (auto& op : program.ops) {
+      lite::pb::OpDesc desc(op->op_info()->desc());
+      auto kernel_type = desc.GetAttr(kKernelTypeAttr).get<std::string>();
+      std::string op_type, alias;
+      Place place;
+      KernelBase::ParseKernelType(kernel_type, &op_type, &alias, &place);
+      auto kernels = op->CreateKernels({place});
+      // filter out a kernel
+      auto it = std::find_if(kernels.begin(), kernels.end(),
+                             [&](std::unique_ptr<KernelBase>& it) {
+                               return it->alias() == alias;
+                             });
+      CHECK(it != kernels.end());
+      insts.emplace_back(op, std::move(*it));
+    }
+    program_.reset(new RuntimeProgram(std::move(insts)));
+    CHECK(program.exec_scope);
+    program_->set_exec_scope(program.exec_scope);
+  }
+
+ private:
+  std::shared_ptr<Scope> scope_;
+  std::unique_ptr<RuntimeProgram> program_;
+};
+
+}  // namespace lite
+}  // namespace paddle

paddle/fluid/lite/api/light_api_test.cc

+// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed 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.
+
+#include "paddle/fluid/lite/api/light_api.h"
+#include <gtest/gtest.h>
+
+namespace paddle {
+namespace lite {
+
+const std::string model_dir =
+    "/home/chunwei/project/Paddle/cmake-build-relwithdebinfo/paddle/fluid/lite/"
+    "api/optimized_model";
+
+TEST(LightAPI, load) {
+  CxxPredictor predictor;
+  predictor.Build(model_dir);
+
+  auto* input_tensor = predictor.GetInput(0);
+  input_tensor->Resize({100, 100});
+  auto* data = input_tensor->mutable_data<float>();
+  for (int i = 0; i < 100 * 100; i++) {
+    data[i] = i;
+  }
+
+  predictor.Run();
+}
+
+}  // namespace lite
+}  // namespace paddle
+
+USE_LITE_OP(mul);
+USE_LITE_OP(fc);
+USE_LITE_OP(scale);
+USE_LITE_OP(feed);
+USE_LITE_OP(fetch);
+USE_LITE_OP(io_copy);
+USE_LITE_KERNEL(fc, kHost, kFloat, kNCHW, def);
+USE_LITE_KERNEL(mul, kHost, kFloat, kNCHW, def);
+USE_LITE_KERNEL(scale, kHost, kFloat, kNCHW, def);
+USE_LITE_KERNEL(feed, kHost, kAny, kAny, def);
+USE_LITE_KERNEL(fetch, kHost, kAny, kAny, def);

paddle/fluid/lite/core/CMakeLists.txt

@@ -21,7 +21,7 @@ cc_library(program_lite SRCS program.cc DEPS op_lite kernel_lite)
 cc_library(optimizer_lite SRCS optimizer.cc DEPS mir_pass_manager model_parser_lite program_lite)
 
 cc_test(test_scope_lite SRCS scope_test.cc DEPS scope_lite)
-cc_test(test_kernel_lite SRCS kernel_test.cc DEPS target_wrapper_x86)
+cc_test(test_kernel_lite SRCS kernel_test.cc DEPS kernel_lite target_wrapper_x86)
 cc_test(test_op_lite SRCS op_lite_test.cc DEPS op_lite)
 cc_test(test_tensor_lite SRCS tensor_test.cc)
 cc_test(test_op_executor_lite SRCS op_executor_test.cc DEPS op_executor_lite ops_lite host_kernels)

paddle/fluid/lite/core/kernel.h

@@ -96,14 +96,40 @@ class KernelBase {
   // Generate the key of the parameter type.
   std::string GenParamTypeKey() const;
 
-  std::string SerializeKernelType() const {
+  std::string SerializedKernelType() const {
+    return SerializeKernelType(op_type(), alias(), place());
+  }
+
+  static std::string SerializeKernelType(const std::string& op_type,
+                                         const std::string& alias,
+                                         const Place& place) {
     std::stringstream ss;
-    ss << op_type() << "/";
-    ss << alias_ << "/";
-    ss << place();
+    ss << op_type << "/";
+    ss << alias << "/";
+    // We serialize the place value not the string representation here for
+    // easier deserialization.
+    ss << static_cast<int>(place.target) << "/";
+    ss << static_cast<int>(place.precision) << "/";
+    ss << static_cast<int>(place.layout);
     return ss.str();
   }
 
+  static void ParseKernelType(const std::string& kernel_type,
+                              std::string* op_type, std::string* alias,
+                              Place* place) {
+    std::stringstream ss(kernel_type);
+    std::getline(ss, *op_type, '/');
+    std::getline(ss, *alias, '/');
+    std::string target, precision, layout;
+    std::getline(ss, target, '/');
+    std::getline(ss, precision, '/');
+    std::getline(ss, layout, '/');
+
+    place->target = static_cast<TargetType>(std::stoi(target));
+    place->precision = static_cast<PrecisionType>(std::stoi(precision));
+    place->layout = static_cast<DataLayoutType>(std::stoi(layout));
+  }
+
   virtual ~KernelBase() = default;
   void Torch() {}
 

paddle/fluid/lite/core/kernel_test.cc

@@ -42,6 +42,22 @@ TEST(Kernel, test) {
   ASSERT_EQ(test_code, 100);
 }
 
+TEST(Kernel, kernel_type) {
+  const std::string op_type = "fc";
+  const std::string alias = "def";
+  Place place(TARGET(kHost), PRECISION(kFloat), DATALAYOUT(kNCHW));
+  auto kernel_type = KernelBase::SerializeKernelType(op_type, alias, place);
+  LOG(INFO) << "kernel_type: " << kernel_type;
+  ASSERT_EQ(kernel_type, "fc/def/1/1/1");
+
+  std::string op_type1, alias1;
+  Place place1;
+  KernelBase::ParseKernelType(kernel_type, &op_type1, &alias1, &place1);
+  ASSERT_EQ(op_type, op_type1);
+  ASSERT_EQ(alias, alias1);
+  ASSERT_EQ(place, place1);
+}
+
 }  // namespace core
 }  // namespace lite
 }  // namespace paddle

paddle/fluid/lite/core/mir/generate_program_pass.h

@@ -38,7 +38,7 @@ class GenerateProgramPass : public ProgramPass {
   }
 
  private:
-  std::vector<Instruction> insts_;
+  std::vector<Instruct> insts_;
 };
 
 }  // namespace mir

paddle/fluid/lite/core/program.cc

@@ -18,53 +18,48 @@
 namespace paddle {
 namespace lite {
 
-void RuntimeProgram::PersistModel(const std::string &path,
+void RuntimeProgram::PersistModel(const std::string &dir,
                                   const framework::proto::ProgramDesc &desc) {
   // Persist model.
-  const std::string model_path = path + "/__model__";
+  const std::string model_path = dir + "/__model__";
   std::ofstream model_ostream(model_path, std::ios_base::binary);
   CHECK(model_ostream.is_open());
-  const std::string pb_str = SerializeModelTopology(desc);
+  const std::string pb_str = SerializeProgram(desc);
   model_ostream.write(pb_str.c_str(), pb_str.size());
+  model_ostream.close();
 
   // Persist params.
-  const std::string params_path = path + "/params";
-  CHECK(!IsFileExists(params_path)) << "file " << params_path
-                                    << " exists, can't overwrite";
-  std::ofstream params_ostream(params_path, std::ios_base::binary);
-  CHECK(params_ostream.is_open());
   framework::proto::ProgramDesc latest_program;
   latest_program.ParseFromString(pb_str);
-  SerializeParams(params_ostream, latest_program);
+  SaveParams(dir, latest_program);
 }
 
-std::string RuntimeProgram::SerializeModelTopology(
+std::string RuntimeProgram::SerializeProgram(
     const framework::proto::ProgramDesc &desc) {
-  const std::string kKernelTypeAttr = "__@kernel_type_attr@__";
   auto program_dummy = desc;
   program_dummy.mutable_blocks(0)->clear_ops();
   for (auto &node : instructions_) {
     auto desc_dummy = node.op()->op_info()->desc();
     OpDesc desc(desc_dummy);
-    desc.SetAttr(kKernelTypeAttr, node.kernel()->SerializeKernelType());
+    desc.SetAttr(kKernelTypeAttr, node.kernel()->SerializedKernelType());
     // append new opdesc
     *program_dummy.mutable_blocks(0)->add_ops() = *desc.Proto();
   }
   return program_dummy.SerializeAsString();
 }
 
-void RuntimeProgram::SerializeParams(
-    std::ostream &os, const framework::proto::ProgramDesc &desc) {
-  std::vector<std::string> ws;
+void RuntimeProgram::SaveParams(const std::string &dir,
+                                const framework::proto::ProgramDesc &desc) {
+  CHECK(exec_scope_);
   for (auto &item : desc.blocks(0).vars()) {
+    const std::string path = dir + "/" + item.name();
     if (item.name() == "feed" || item.name() == "fetch") continue;
     if (item.persistable()) {
-      ws.push_back(item.name());
+      std::ofstream file(path, std::ios::binary);
+      SerializeTensor(file, *exec_scope_, item.name());
+      file.close();
     }
   }
-
-  CHECK(exec_scope_);
-  SerializeTensors(os, *exec_scope_, ws);
 }
 
 }  // namespace lite

paddle/fluid/lite/core/program.h

@@ -26,6 +26,8 @@
 namespace paddle {
 namespace lite {
 
+static const std::string kKernelTypeAttr = "__@kernel_type_attr@__";
+
 // A program is used to represent a code program, in Paddle, a code program
 // contains:
 // - main block, which is a list of OpLite
@@ -46,8 +48,9 @@ struct Program {
           const std::shared_ptr<Scope>& root,
           const std::vector<Place>& valid_places)
       : scope(root), valid_places(valid_places), desc(desc) {
+    CHECK(scope) << "scope should be init first";
     PrepareWorkspace(desc);
-    Build(desc, valid_places);
+    Build(desc);
   }
 
   std::unique_ptr<Program> Clone() const {
@@ -57,8 +60,7 @@ struct Program {
 
  private:
   // Build from a program and scope.
-  void Build(const framework::proto::ProgramDesc& program,
-             const std::vector<Place>& valid_places) {
+  void Build(const framework::proto::ProgramDesc& program) {
     CHECK(ops.empty()) << "Executor duplicate Build found";
 
     // Create operators.
@@ -67,7 +69,9 @@ struct Program {
       auto op_type = op_desc.Type();
       // if (op_type == "feed" || op_type == "fetch") continue;
       VLOG(4) << "create Op [" << op_type << "]";
-      ops.emplace_back(LiteOpRegistry::Global().Create(op_type));
+      auto op = LiteOpRegistry::Global().Create(op_type);
+      CHECK(op) << "no Op found for " << op_type;
+      ops.emplace_back(op);
       ops.back()->Attach(op_desc, exec_scope);
     }
   }
@@ -95,9 +99,9 @@ struct Program {
   }
 };
 
-struct Instruction {
-  Instruction(const std::shared_ptr<OpLite>& op,
-              std::unique_ptr<KernelBase>&& kernel)
+struct Instruct {
+  Instruct(const std::shared_ptr<OpLite>& op,
+           std::unique_ptr<KernelBase>&& kernel)
       : op_(op), kernel_(std::move(kernel)) {}
 
   void Run() {
@@ -111,7 +115,7 @@ struct Instruction {
     kernel_->Run();
   }
 
-  friend std::ostream& operator<<(std::ostream& os, const Instruction& other) {
+  friend std::ostream& operator<<(std::ostream& os, const Instruct& other) {
     os << other.kernel_->summary() << "\t(" << other.kernel_->doc() << ")";
     return os;
   }
@@ -130,7 +134,7 @@ struct Instruction {
  */
 class RuntimeProgram {
  public:
-  explicit RuntimeProgram(std::vector<Instruction>&& insts)
+  explicit RuntimeProgram(std::vector<Instruct>&& insts)
       : instructions_(std::move(insts)) {
     if (instructions_.empty()) {
       LOG(FATAL) << "no instructions";
@@ -145,7 +149,7 @@ class RuntimeProgram {
   }
 
   // Serialize the graph and save to the disk.
-  void PersistModel(const std::string& path,
+  void PersistModel(const std::string& dir,
                     const framework::proto::ProgramDesc& desc);
 
   void set_exec_scope(lite::Scope* x) { exec_scope_ = x; }
@@ -154,13 +158,13 @@ class RuntimeProgram {
   size_t num_instructions() const { return instructions_.size(); }
 
  protected:
-  std::string SerializeModelTopology(const framework::proto::ProgramDesc& desc);
-  void SerializeParams(std::ostream& os,
-                       const framework::proto::ProgramDesc& desc);
+  std::string SerializeProgram(const framework::proto::ProgramDesc& desc);
+  void SaveParams(const std::string& dir,
+                  const framework::proto::ProgramDesc& desc);
 
  private:
   RuntimeProgram(const RuntimeProgram&) = delete;
-  std::vector<Instruction> instructions_;
+  std::vector<Instruct> instructions_;
   lite::Scope* exec_scope_{};
 };
 

paddle/fluid/lite/host/CMakeLists.txt

-cc_library(target_wrapper_host SRCS target_wrapper.cc)
+cc_library(target_wrapper_host SRCS target_wrapper.cc DEPS target_wrapper_lite)

paddle/fluid/lite/model_parser/CMakeLists.txt

@@ -6,8 +6,13 @@ else()
     cc_library(compatible_pb_lite SRCS compatible_pb.cc DEPS framework_proto)
 endif(LITE_WITH_LIGHT_WEIGHT_FRAMEWORK)
 
-cc_library(model_parser_lite SRCS model_parser.cc DEPS variable_lite scope_lite tensor_lite scope_lite
-compatible_pb_lite)
-
+set(model_parser_deps variable_lite scope_lite tensor_lite scope_lite
+                      target_wrapper_host
+                      compatible_pb_lite
+                      )
+if (LITE_WITH_CUDA)
+    set(model_parser_deps ${model_parser_deps} target_wrapper_cuda)
+endif()
+cc_library(model_parser_lite SRCS model_parser.cc DEPS ${model_parser_deps})
 
 add_subdirectory(pb)

paddle/fluid/lite/model_parser/model_parser.cc

@@ -35,7 +35,7 @@ int SizeOfType(framework::proto::VarType::Type type) {
     DO(INT64, int64_t);
 #undef DO
     default:
-      LOG(FATAL) << "unknown data type";
+      LOG(FATAL) << "unknown data type " << type;
   }
   return -1;
 }
@@ -86,12 +86,12 @@ void TensorFromStream(std::istream &is, lite::Tensor *tensor) {
 
 void LoadLoDTensor(std::istream &is, Variable *var) {
   auto *tensor = var->GetMutable<lite::Tensor>();
-  uint32_t version;
+  uint32_t version{};
   is.read(reinterpret_cast<char *>(&version), sizeof(version));
   LOG(INFO) << "model version " << version;
 
   // Load LoD information
-  uint64_t lod_level;
+  uint64_t lod_level{};
   is.read(reinterpret_cast<char *>(&lod_level), sizeof(lod_level));
   auto &lod = *tensor->mutable_lod();
   lod.resize(lod_level);
@@ -136,6 +136,7 @@ void LoadParams(const std::string &path) {}
 // Load directly to CPU, and latter transfer to other devices.
 void LoadParam(const std::string &path, Variable *out) {
   std::ifstream fin(path, std::ios::binary);
+  CHECK(fin.is_open()) << "failed to open file " << path;
   LoadLoDTensor(fin, out);
 }
 
@@ -164,13 +165,12 @@ void LoadModel(const std::string &model_dir, Scope *scope,
 }
 
 void TensorToStream(std::ostream &os, const lite::Tensor &tensor) {
-  {  // the 1st field, uint32_t version
-    constexpr uint32_t version = 0;
-    os.write(reinterpret_cast<const char *>(&version), sizeof(version));
-  }
+  // the 1st field, uint32_t version
+  constexpr uint32_t version = 0;
+  os.write(reinterpret_cast<const char *>(&version), sizeof(version));
 
   {
-    int size = tensor.lod().size();
+    uint64_t size = tensor.lod().size();
     // the 2st field, LoD information
     // uint64_t lod_level
     // uint64_t lod_level_1 size in byte.
@@ -186,11 +186,15 @@ void TensorToStream(std::ostream &os, const lite::Tensor &tensor) {
     }
   }
 
+  // There are two version fields in a LoDTensor.
+  os.write(reinterpret_cast<const char *>(&version), sizeof(version));
+
   {  // the 2nd field, tensor description
     // int32_t  size
     // void*    protobuf message
     framework::proto::VarType::TensorDesc desc;
-    desc.set_data_type(framework::proto::VarType_Type_LOD_TENSOR);
+    // TODO(Superjomn) support other data types.
+    desc.set_data_type(framework::proto::VarType_Type_FP32);
     auto dims = tensor.dims();
     auto *pb_dims = desc.mutable_dims();
     pb_dims->Resize(static_cast<int>(dims.size()), 0);
@@ -221,14 +225,12 @@ void TensorToStream(std::ostream &os, const lite::Tensor &tensor) {
   }
 }
 
-void SerializeTensors(std::ostream &os, const lite::Scope &scope,
-                      const std::vector<std::string> &vars) {
+void SerializeTensor(std::ostream &os, const lite::Scope &scope,
+                     const std::string &var_name) {
   // Store all the persistable vars.
-  for (const auto &_var : vars) {
-    auto *var = scope.FindVar(_var);
-    const auto &tensor = var->Get<lite::Tensor>();
-    TensorToStream(os, tensor);
-  }
+  auto *var = scope.FindVar(var_name);
+  const auto &tensor = var->Get<lite::Tensor>();
+  TensorToStream(os, tensor);
 }
 
 }  // namespace lite

paddle/fluid/lite/model_parser/model_parser.h

@@ -41,8 +41,8 @@ void LoadModel(const std::string& model_dir, Scope* scope,
                framework::proto::ProgramDesc* prog);
 
 // Serialize tensors to ostream.
-void SerializeTensors(std::ostream& os, const lite::Scope& scope,
-                      const std::vector<std::string>& vars);
+void SerializeTensor(std::ostream& os, const lite::Scope& scope,
+                     const std::string& var);
 
 // LoDTensor to ostream
 void TensorToStream(std::ostream& os, const lite::Tensor& tensor);

paddle/fluid/lite/x86/target_wrapper.cc

@@ -22,7 +22,7 @@ namespace lite {
 template <>
 void TargetWrapper<TARGET(kX86)>::MemcpySync(void *dst, const void *src,
                                              size_t size, IoDirection dir) {
-  std::copy_n(reinterpret_cast<uint8_t *>(src), size,
+  std::copy_n(reinterpret_cast<const uint8_t *>(src), size,
               reinterpret_cast<uint8_t *>(dst));
 }