diff --git a/aot/options.cpp b/aot/options.cpp
index c5a15797fb19be31747698c3fd296f39657642b6..35361a487248690d5a0c445ced968af20db0285d 100644
--- a/aot/options.cpp
+++ b/aot/options.cpp
@@ -78,7 +78,7 @@ bool Options::Parse(int argc, const char **argv)
     panda::PandArg<bool> op_ets_module("ets-module", false, "Compile the input as ets-module");
     panda::PandArg<std::string> op_ts_decl_out("gen-ts-decl", "", "For given .ets file, generate .ts interop file");
 
-    auto constexpr DEFAULT_THREAD_COUNT = 2;
+    auto constexpr DEFAULT_THREAD_COUNT = 0;
     panda::PandArg<int> op_thread_count("thread", DEFAULT_THREAD_COUNT, "Number of worker threads");
     panda::PandArg<bool> op_size_stat("dump-size-stat", false, "Dump size statistics");
     panda::PandArg<std::string> output_file("output", "", "Compiler binary output (.abc)");
diff --git a/binder/ETSBinder.h b/binder/ETSBinder.h
index 5958839e7d54216599b1ebe54dbb9267f62ed581..481b2347103dc8ef96c0586fe6ed53e9eba99c73 100644
--- a/binder/ETSBinder.h
+++ b/binder/ETSBinder.h
@@ -22,8 +22,7 @@
 
 namespace panda::es2panda::binder {
 
-using ComputedLambdaObjects =
-    ArenaUnorderedMap<const ir::AstNode *, std::pair<ir::ClassDefinition *, checker::Signature *>>;
+using ComputedLambdaObjects = ArenaMap<const ir::AstNode *, std::pair<ir::ClassDefinition *, checker::Signature *>>;
 
 struct DynamicImportData {
     const ir::ETSImportDeclaration *import;
@@ -83,12 +82,12 @@ public:
         return &global_record_table_;
     }
 
-    ArenaUnorderedMap<parser::Program *, RecordTable *> &GetExternalRecordTable()
+    ArenaMap<parser::Program *, RecordTable *> &GetExternalRecordTable()
     {
         return external_record_table_;
     }
 
-    const ArenaUnorderedMap<parser::Program *, RecordTable *> &GetExternalRecordTable() const
+    const ArenaMap<parser::Program *, RecordTable *> &GetExternalRecordTable() const
     {
         return external_record_table_;
     }
@@ -194,7 +193,7 @@ private:
 
     RecordTable global_record_table_;
     RecordTable *record_table_;
-    ArenaUnorderedMap<parser::Program *, RecordTable *> external_record_table_;
+    ArenaMap<parser::Program *, RecordTable *> external_record_table_;
     ArenaVector<ir::ETSImportDeclaration *> default_imports_;
     ArenaVector<ir::ETSImportDeclaration *> dynamic_imports_;
     ComputedLambdaObjects lambda_objects_;
diff --git a/binder/recordTable.h b/binder/recordTable.h
index 59cf5ef16d83582497f1be8e4fbf26b29381a8bf..2847f164f952ea8b1ed475013f6df9eb2b778f86 100644
--- a/binder/recordTable.h
+++ b/binder/recordTable.h
@@ -67,22 +67,22 @@ public:
         return (flags_ & RecordTableFlags::EXTERNAL) != 0;
     }
 
-    ArenaUnorderedSet<ir::ClassDefinition *> &ClassDefinitions()
+    ArenaSet<ir::ClassDefinition *> &ClassDefinitions()
     {
         return class_definitions_;
     }
 
-    const ArenaUnorderedSet<ir::ClassDefinition *> &ClassDefinitions() const
+    const ArenaSet<ir::ClassDefinition *> &ClassDefinitions() const
     {
         return class_definitions_;
     }
 
-    ArenaUnorderedSet<ir::TSInterfaceDeclaration *> &InterfaceDeclarations()
+    ArenaSet<ir::TSInterfaceDeclaration *> &InterfaceDeclarations()
     {
         return interface_declarations_;
     }
 
-    const ArenaUnorderedSet<ir::TSInterfaceDeclaration *> &InterfaceDeclarations() const
+    const ArenaSet<ir::TSInterfaceDeclaration *> &InterfaceDeclarations() const
     {
         return interface_declarations_;
     }
@@ -154,8 +154,8 @@ private:
     friend class BoundContext;
     using RecordHolder = std::variant<ir::ClassDefinition *, ir::TSInterfaceDeclaration *, std::nullptr_t>;
 
-    ArenaUnorderedSet<ir::ClassDefinition *> class_definitions_;
-    ArenaUnorderedSet<ir::TSInterfaceDeclaration *> interface_declarations_;
+    ArenaSet<ir::ClassDefinition *> class_definitions_;
+    ArenaSet<ir::TSInterfaceDeclaration *> interface_declarations_;
     ArenaVector<binder::FunctionScope *> signatures_;
     RecordHolder record_ {nullptr};
     parser::Program *program_ {};
diff --git a/compiler/core/emitter.cpp b/compiler/core/emitter.cpp
index 0891cfe7dd533f03811a7b1381f9a448f9b23328..2c5f4f0943acb2f1021bea38404d7de99445d385 100644
--- a/compiler/core/emitter.cpp
+++ b/compiler/core/emitter.cpp
@@ -384,7 +384,7 @@ static void UpdateLiteralBufferId([[maybe_unused]] panda::pandasm::Ins *ins, [[m
 
 void Emitter::AddProgramElement(ProgramElement *program_element)
 {
-    prog_->strings.merge(program_element->Strings());
+    prog_->strings.insert(program_element->Strings().begin(), program_element->Strings().end());
 
     uint32_t new_literal_buffer_index = literal_buffer_index_;
     for (const auto &buff : program_element->BuffStorage()) {
diff --git a/compiler/core/programElement.cpp b/compiler/core/programElement.cpp
index e603e0ac7585176f1a08cc7dce90f991f3ad2da6..bbbdd130eeabb16f52e78539650211ffd7190ec3 100644
--- a/compiler/core/programElement.cpp
+++ b/compiler/core/programElement.cpp
@@ -18,7 +18,7 @@
 #include <assembly-program.h>
 
 namespace panda::es2panda::compiler {
-std::unordered_set<std::string> &ProgramElement::Strings()
+std::set<std::string> &ProgramElement::Strings()
 {
     return strings_;
 }
diff --git a/compiler/core/programElement.h b/compiler/core/programElement.h
index 0fc4d3bb3239436c406d67f6e96505b847b97b3b..db5bd11d145fe9109e8f0d7efb0c3a155988149f 100644
--- a/compiler/core/programElement.h
+++ b/compiler/core/programElement.h
@@ -32,14 +32,14 @@ public:
     NO_COPY_SEMANTIC(ProgramElement);
     NO_MOVE_SEMANTIC(ProgramElement);
 
-    std::unordered_set<std::string> &Strings();
+    std::set<std::string> &Strings();
     std::vector<pandasm::Ins *> &LiteralBufferIns();
     std::vector<LiteralBuffer> &BuffStorage();
     pandasm::Function *Function();
     void SetFunction(pandasm::Function *func);
 
 private:
-    std::unordered_set<std::string> strings_;
+    std::set<std::string> strings_;
     std::vector<pandasm::Ins *> literal_buffer_ins_;
     std::vector<LiteralBuffer> buff_storage_;
     pandasm::Function *func_ {};