[backend-O1-1]修复了寄存器分配器在处理函数参数时不健壮的问题

src/include/backend/RISCv64/RISCv64LLIR.h

@@ -326,12 +326,19 @@ public:
     void addBlock(std::unique_ptr<MachineBasicBlock> block) {
         blocks.push_back(std::move(block));
     }
+    void addProtectedArgumentVReg(unsigned vreg) {
+        protected_argument_vregs.insert(vreg);
+    }
+    const std::set<unsigned>& getProtectedArgumentVRegs() const {
+        return protected_argument_vregs;
+    }
 private:
     Function* F;
     RISCv64ISel* isel; // 指向创建它的ISel，用于获取vreg映射等信息
     std::string name;
     std::vector<std::unique_ptr<MachineBasicBlock>> blocks;
     StackFrameInfo frame_info;
+    std::set<unsigned> protected_argument_vregs;
 };
 inline bool isMemoryOp(RVOpcodes opcode) {
     switch (opcode) {