refactor: 重构前端代码并添加日志功能

- 重命名和重构了多个文件，包括 lexer、parser 和 AST 相关代码
- 添加了日志功能，使用 LOG_* 宏替代原有的 error 和 warn 函数
- 优化了错误处理和内存分配方式
- 调整了代码结构，提高了模块化和可读性

ccompiler/middleend/ir/ir_lib.c

@@ -0,0 +1,118 @@
+#include "ir.h"
+
+// FIXME using stdlib.h
+#include <stdlib.h>
+
+static int total_alloc = 0;
+typedef union ir_alloc_item {
+    ir_node_t node;
+    ir_bblock_t bblock;
+    ir_func_t func;
+    ir_prog_t prog;
+} ir_alloc_item_t;
+
+ir_alloc_item_t* alloc_item() {
+    return malloc(sizeof(ir_alloc_item_t));
+}
+
+void free_item(ir_alloc_item_t* item) {
+    return free(item);
+}
+
+ir_node_t* new_ir_node(const char* name, ir_node_tag_t tag) {
+    ir_node_t* node = (ir_node_t*)alloc_item();
+    node->name = name;
+    node->type = NULL;
+    node->tag = tag;
+    switch (tag) {
+        case IR_NODE_ALLOC: {
+            node->type = NULL;
+            break;
+        }
+        case IR_NODE_BRANCH: {
+            node->data.branch.cond = NULL;
+            node->data.branch.true_bblock = NULL;
+            node->data.branch.false_bblock = NULL;
+            break;
+        }
+        case IR_NODE_CALL: {
+            vector_init(node->data.call.args);
+            node->data.call.callee = NULL;
+            break;
+        }
+        case IR_NODE_CONST_INT: {
+            node->data.const_int.val = 0;
+            break;
+        }
+        case IR_NODE_JUMP: {
+            node->data.jump.target_bblock = NULL;
+            break;
+        }
+        case IR_NODE_LOAD: {
+            node->data.load.target = NULL;
+            break;
+        }
+        case IR_NODE_STORE: {
+            node->data.store.target = NULL;
+            node->data.store.value = NULL;
+            break;
+        }
+        case IR_NODE_OP: {
+            node->data.op.op = 0;
+            node->data.op.lhs = NULL;
+            node->data.op.rhs = NULL;
+            break;
+        }
+        case IR_NODE_RET: {
+            node->data.ret.ret_val = NULL;
+            break;
+        }
+        case IR_NODE_GET_PTR: {
+        }
+        default: {
+            exit(0);
+        }
+    }
+    vector_init(node->used_by);
+    return node;
+}
+
+void free_irnode() {
+
+}
+
+ir_bblock_t* new_ir_bblock(const char* name) {
+    ir_bblock_t* block = (ir_bblock_t*)alloc_item();
+    block->label = name;
+    vector_init(block->instrs);
+    return block;
+}
+
+void free_irbblock() {
+
+}
+
+ir_func_t* new_ir_func(const char* name, ir_type_t* type) {
+    ir_func_t* func = (ir_func_t*)alloc_item();
+    func->name = name;
+    func->type = type;
+    vector_init(func->params);
+    vector_init(func->bblocks);
+    return func;
+}
+
+void free_irfunc() {
+
+}
+
+ir_prog_t* new_ir_prog() {
+    ir_prog_t* prog = (ir_prog_t*)alloc_item();
+    vector_init(prog->global);
+    vector_init(prog->funcs);
+    vector_init(prog->extern_funcs);
+    return prog;
+}
+
+void free_irprog() {
+
+}