fix(ir): 修改了一下context的管理

src/ir/BasicBlock.cpp

@@ -12,6 +12,10 @@ BasicBlock::BasicBlock(std::string name) : name_(std::move(name)) {}
 
 const std::string& BasicBlock::name() const { return name_; }
 
+Function* BasicBlock::parent() const { return parent_; }
+
+void BasicBlock::set_parent(Function* parent) { parent_ = parent; }
+
 bool BasicBlock::HasTerminator() const {
   return !instructions_.empty() && instructions_.back()->IsTerminator();
 }
@@ -21,4 +25,12 @@ const std::vector<std::unique_ptr<Instruction>>& BasicBlock::instructions()
   return instructions_;
 }
 
+const std::vector<BasicBlock*>& BasicBlock::predecessors() const {
+  return predecessors_;
+}
+
+const std::vector<BasicBlock*>& BasicBlock::successors() const {
+  return successors_;
+}
+
 }  // namespace ir