[backend]为图着色引入保底修复

src/backend/RISCv64/CMakeLists.txt

@@ -5,6 +5,7 @@ add_library(riscv64_backend_lib STATIC
     RISCv64ISel.cpp
     RISCv64LLIR.cpp
     RISCv64RegAlloc.cpp
+    RISCv64LinearScan.cpp
     Handler/CalleeSavedHandler.cpp
     Handler/LegalizeImmediates.cpp
     Handler/PrologueEpilogueInsertion.cpp