[Core] Move constant-folded variable from exec scope to root scope fo…

…r fix predictor clone error (#9062)

lite/api/cxx_api.cc

@@ -176,7 +176,7 @@ lite::Tensor *Predictor::GetInput(size_t offset) {
       << "The network has " << input_names_.size() << " inputs"
       << ", the offset should be less than this.";
   auto *in_var = exec_scope_->FindVar(input_names_[offset]);
-  CHECK(in_var) << "no fatch variable " << input_names_[offset]
+  CHECK(in_var) << "no feed variable " << input_names_[offset]
                 << " in exec_scope";
   return in_var->GetMutable<lite::Tensor>();
 }
@@ -249,7 +249,7 @@ const lite::Tensor *Predictor::GetOutput(size_t offset) const {
       << ", the offset should be less than this.";
   const std::string name = output_names_.at(offset);
   auto *out_var = exec_scope_->FindVar(name);
-  CHECK(out_var) << "no fatch variable " << name << " in exec_scope";
+  CHECK(out_var) << "no fetch variable " << name << " in exec_scope";
   return out_var->GetMutable<lite::Tensor>();
 }
 
@@ -265,15 +265,15 @@ std::vector<const lite::Tensor *> Predictor::GetOutputs() const {
 #else
 const lite::Tensor *Predictor::GetOutput(size_t offset) const {
   auto *_fetch_list = exec_scope_->FindVar("fetch");
-  CHECK(_fetch_list) << "no fatch variable in exec_scope";
+  CHECK(_fetch_list) << "no fetch 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);
 }
 
 std::vector<const lite::Tensor *> Predictor::GetOutputs() const {
   auto *_fetch_list = exec_scope_->FindVar("fetch");
-  CHECK(_fetch_list) << "no fatch variable in exec_scope";
+  CHECK(_fetch_list) << "no fetch variable in exec_scope";
   auto &fetch_list = *_fetch_list->GetMutable<std::vector<lite::Tensor>>();
 
   std::vector<const lite::Tensor *> outputs;

lite/api/cxx_api.h

@@ -113,7 +113,7 @@ class LITE_API Predictor {
     if (!program_generated_) {
       GenRuntimeProgram();
     }
-    // step 2. Create a predictor friom current program_desc_ and
+    // step 2. Create a predictor from current program_desc_ and
     // runtime_program.
     auto predictor =
         std::make_shared<Predictor>(program_desc_, scope_, valid_places_);

lite/core/program.cc

@@ -87,6 +87,18 @@ void UpdateVarDescFromTensorInfo(cpp::VarDesc* var,
   var->SetType(cpp::VarDesc::Type::LOD_TENSOR);
   auto tensor = scope->FindVar(var_name)->GetMutable<Tensor>();
   var->SetPersistable(tensor->persistable());
+  // Move the persistable var from exec scope to the root scope
+  auto root_scope = scope->MutableParent();
+  if (tensor->persistable() && root_scope != scope &&
+      !root_scope->FindLocalVar(var_name)) {
+    // Find or create new var in root scope
+    auto root_tensor = root_scope->LocalVar(var_name)->GetMutable<Tensor>();
+    if (root_tensor != tensor) {
+      root_tensor->CopyDataFrom(*tensor);
+      scope->DeleteLocalVar(var_name);
+    }
+  }
+
   if (var_name != "feed" && var_name != "fetch") {
     var->SetShape(tensor->dims().data());
     auto precision = tensor->precision();
@@ -579,8 +591,7 @@ void Program::PrepareWorkspace(
 #if defined(LITE_WITH_XPU) || defined(LITE_WITH_CUDA)
       }
 #endif
-
-      // Create tensors or wights from variable description.
+      // Create tensors or weights from variable description.
       if (!var_desc->Persistable()) {
         vars_.push_back(var_name);
         auto* var = exec_scope_->Var(var_name);
@@ -603,6 +614,7 @@ void Program::PrepareWorkspace(
             VLOG(4) << " - dims " << tensor->dims().repr();
           }
           tensor->set_precision(var_data_type);
+          tensor->set_persistable(var_desc->Persistable());
         } else if (var_type == lite::VarDescAPI::Type::LOD_TENSOR_ARRAY) {
           var_type_map_[var_name] = LiteType::GetTensorListTy(
               TARGET(kUnk), PRECISION(kUnk), DATALAYOUT(kUnk));

lite/core/scope.cc

@@ -83,6 +83,19 @@ Variable *Scope::FindLocalVar(const std::string &name) const {
   return nullptr;
 }
 
+void Scope::DeleteLocalVar(const std::string &name) {
+  rwlock_->RDLock();
+  if (FindLocalVar(name)) {
+    auto *p = vars_[name].release();
+    if (!p) {
+      delete p;
+      p = nullptr;
+    }
+    vars_.erase(name);
+  }
+  rwlock_->UNLock();
+}
+
 // AttributeVarNames will get persistive attribute names stored in parent scope
 std::vector<std::string> Scope::AttributeVarNames() const {
   std::vector<std::string> resulted_keys;

lite/core/scope.h

@@ -49,6 +49,8 @@ class Scope final {
 
   Variable* FindLocalVar(const std::string& name) const;
 
+  void DeleteLocalVar(const std::string& name);
+
   const Scope* parent() const { return parent_; }
   Scope* MutableParent() { return const_cast<Scope*>(parent_); }