[backend]完善了后端流水线

src/backend/RISCv64/RISCv64RegAlloc.cpp

@@ -45,7 +45,7 @@ RISCv64RegAlloc::RISCv64RegAlloc(MachineFunction* mfunc)
 }
 
 // 主入口: 迭代运行分配算法直到无溢出
-void RISCv64RegAlloc::run() {
+bool RISCv64RegAlloc::run() {
     if (DEBUG) std::cerr << "===== LLIR Before Running Graph Coloring Register Allocation " << MFunc->getName() << " =====\n";
     std::stringstream ss_before_reg_alloc;
     if (DEBUG) {
@@ -108,6 +108,7 @@ void RISCv64RegAlloc::run() {
     MFunc->getFrameInfo().vreg_to_preg_map = this->color_map;
     collectUsedCalleeSavedRegs();
     if (DEBUG) std::cerr << "===== Finished Graph Coloring Register Allocation =====\n\n";
+    return true;
 }
 
 // 单次分配的核心流程