[midend]重构中端，建立遍管理器，注册器等，初步构建支配树分析遍，增加基本块方法

src/include/IR.h

@@ -522,12 +522,20 @@ public:
   void setParent(Function *func) { parent = func; }
   inst_list& getInstructions() { return instructions; }
   arg_list& getArguments() { return arguments; }
-  const block_list& getPredecessors() const { return predecessors; }
+  block_list& getPredecessors() { return predecessors; }
+  void clearPredecessors() { predecessors.clear(); }
   block_list& getSuccessors() { return successors; }
+  void clearSuccessors() { successors.clear(); }
   iterator begin() { return instructions.begin(); }
   iterator end() { return instructions.end(); }
   iterator terminator() { return std::prev(end()); }
   void insertArgument(AllocaInst *inst) { arguments.push_back(inst); }
+  bool hasSuccessor(BasicBlock *block) const {
+    return std::find(successors.begin(), successors.end(), block) != successors.end();
+  }  ///< 判断是否有后继块
+  bool hasPredecessor(BasicBlock *block) const {
+    return std::find(predecessors.begin(), predecessors.end(), block) != predecessors.end();
+  }  ///< 判断是否有前驱块
   void addPredecessor(BasicBlock *block) {
     if (std::find(predecessors.begin(), predecessors.end(), block) == predecessors.end()) {
       predecessors.push_back(block);
@@ -580,6 +588,15 @@ public:
     next->addPredecessor(prev);
   }
   void removeInst(iterator pos) { instructions.erase(pos); }
+  void removeInst(Instruction *inst) {
+    auto pos = std::find_if(instructions.begin(), instructions.end(),
+                            [inst](const std::unique_ptr<Instruction> &i) { return i.get() == inst; });
+    if (pos != instructions.end()) {
+      instructions.erase(pos);
+    } else {
+      assert(false && "Instruction not found in BasicBlock");
+    }
+  }  ///< 移除指定位置的指令
   iterator moveInst(iterator sourcePos, iterator targetPos, BasicBlock *block);
 };