Move from shared_ptr to raw pointer

test=develop

paddle/fluid/imperative/layer.h

@@ -105,7 +105,15 @@ class VarBase {
         grads_(stop_gradient ? nullptr : new VarBase(true)),
         stop_gradient_(stop_gradient) {}
 
-  virtual ~VarBase() {}
+  virtual ~VarBase() {
+    if (var_) {
+      delete var_;
+    }
+
+    if (grads_) {
+      delete grads_;
+    }
+  }
 
   void RunBackward();
 
@@ -124,8 +132,8 @@ class VarBase {
 
   framework::VarDesc* var_desc_;
 
-  std::shared_ptr<framework::Variable> var_;
-  std::shared_ptr<VarBase> grads_;
+  framework::Variable* var_;
+  VarBase* grads_;
 
   bool stop_gradient_;
 };

paddle/fluid/imperative/tracer.cc

@@ -58,10 +58,10 @@ void Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
   for (auto it : op->input_vars_) {
     auto& invars = invars_map[it.first];
     for (VarBase* inp : it.second) {
-      PADDLE_ENFORCE_NOT_NULL(inp->var_.get(), "op %s input %s nullptr",
+      PADDLE_ENFORCE_NOT_NULL(inp->var_, "op %s input %s nullptr",
                               op->op_desc_->Type(), inp->var_desc_->Name());
 
-      invars.push_back(inp->var_.get());
+      invars.push_back(inp->var_);
       vars[inp->var_desc_->Name()] = inp;
       if (inp->pre_op_) {
         op->pre_ops_[it.first].push_back(inp->pre_op_);
@@ -80,7 +80,7 @@ void Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
     const std::vector<VarBase*>& outputs = it.second;
     for (size_t i = 0; i < outputs.size(); ++i) {
       VarBase* out = outputs[i];
-      outvars.push_back(out->var_.get());
+      outvars.push_back(out->var_);
       vars[out->var_desc_->Name()] = out;
 
       framework::VarDesc* var_desc = block->FindVar(out->var_desc_->Name());
@@ -127,13 +127,13 @@ void Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
         if (var_it == grad_to_var->end()) {
           auto fwd_var_it = vars.find(grad_invar);
           PADDLE_ENFORCE(fwd_var_it != vars.end());
-          grad_in_vars.push_back(fwd_var_it->second->var_.get());
+          grad_in_vars.push_back(fwd_var_it->second->var_);
         } else {
           VarBase* var = vars[var_it->second];
           if (!var->grads_->var_->IsInitialized()) {
-            InitVar(var->var_.get(), var->grads_->var_.get());
+            InitVar(var->var_, var->grads_->var_);
           }
-          grad_in_vars.push_back(var->grads_->var_.get());
+          grad_in_vars.push_back(var->grads_->var_);
         }
       }
     }
@@ -146,9 +146,9 @@ void Tracer::Trace(OpBase* op, const VarBasePtrMap& inputs,
         PADDLE_ENFORCE(var_it != grad_to_var->end());
         VarBase* var = vars[var_it->second];
         if (!var->grads_->var_->IsInitialized()) {
-          InitVar(var->var_.get(), var->grads_->var_.get());
+          InitVar(var->var_, var->grads_->var_);
         }
-        grad_out_vars.push_back(var->grads_->var_.get());
+        grad_out_vars.push_back(var->grads_->var_);
       }
     }
   }

paddle/fluid/pybind/pybind.cc

@@ -133,10 +133,9 @@ PYBIND11_MODULE(core, m) {
       .def("_grad_name", &imperative::VarBase::GradName)
       .def("_grad_value", &imperative::VarBase::GradValue)
       .def("_grad_ivar",
-           [](const imperative::VarBase &self) { return self.grads_.get(); },
+           [](const imperative::VarBase &self) { return self.grads_; },
            py::return_value_policy::reference)
-      .def("value",
-           [](const imperative::VarBase &self) { return self.var_.get(); },
+      .def("value", [](const imperative::VarBase &self) { return self.var_; },
            py::return_value_policy::reference)
       .def_property(
           "desc",