diff a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.hpp b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.hpp
--- a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.hpp
+++ b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.hpp
@@ -73,10 +73,13 @@
   virtual void load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                        Register dst, Address src, Register tmp1, Register tmp2);
   virtual void store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                         Address dst, Register val, Register tmp1, Register tmp2, Register tmp3);
 
+  virtual void flat_field_copy(MacroAssembler* masm, DecoratorSet decorators,
+                               Register src, Register dst, Register inline_layout_info);
+
   virtual void try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
                                              Register obj, Register tmp, Label& slowpath);
 
   virtual void tlab_allocate(MacroAssembler* masm,
     Register obj,                      // result: pointer to object after successful allocation