Implement basic IR generator

Signed-off-by: CHatingPython <chatingpython@gmail.com>

furc/include/furc/front/ir_generator.hpp

@@ -0,0 +1,44 @@
+#ifndef FURC_FRONT_IR_GENERATOR_HPP
+#define FURC_FRONT_IR_GENERATOR_HPP
+
+#include "furc/ast/fwd.hpp"
+#include "furc/ast/visitor.hpp"
+#include "furlang/ir/module.hpp"
+
+#include <unordered_map>
+
+namespace furc {
+namespace front {
+
+class ir_generator final : public ast::visitor {
+public:
+    ir_generator()           = default;
+    ~ir_generator() override = default;
+
+    ir_generator(ir_generator&&)                 = default;
+    ir_generator& operator=(ir_generator&&)      = default;
+    ir_generator(const ir_generator&)            = default;
+    ir_generator& operator=(const ir_generator&) = default;
+public:
+    furlang::ir::module&& move_module() { return std::move(m_module); }
+public:
+    void visit_function_definition_node(const ast::function_definition_node& funcDef) override;
+    void visit_return_statement_node(const ast::return_statement_node& returnStmt) override;
+    void visit_string_literal_node(const ast::string_literal_node& node) override;
+    void visit_integer_literal_node(const ast::integer_literal_node& node) override;
+    void visit_var_read_expression_node(const ast::var_read_expression_node& node) override;
+    void visit_unaryop_expression_node(const ast::unaryop_expression_node& node) override;
+    void visit_binop_expression_node(const ast::binop_expression_node& node) override;
+    void visit_var_assign_expression_node(const ast::var_assign_expression_node& node) override;
+private:
+    furlang::ir::module                 m_module;
+    std::shared_ptr<furlang::ir::block> m_currentBlock;
+    std::uint32_t                       m_registerCounter = 0;
+
+    std::unordered_map<std::string_view, std::uint32_t> m_variableMap;
+};
+
+} // namespace front
+} // namespace furc
+
+#endif // FURC_FRONT_IR_GENERATOR_HPP