diff --git a/include/picrin/irep.h b/include/picrin/irep.h
index 3494e320..22968e41 100644
--- a/include/picrin/irep.h
+++ b/include/picrin/irep.h
@@ -72,11 +72,9 @@ struct pic_irep {
 pic_value pic_analyze(pic_state *, pic_value);
 struct pic_irep *pic_codegen(pic_state *, pic_value);
 
-inline void
-pic_dump_code(pic_state *pic, pic_code c)
+static inline void
+pic_dump_code(pic_code c)
 {
-  UNUSED(pic);
-
   printf("[%2d] ", c.insn);
   switch (c.insn) {
   case OP_NOP:
@@ -184,8 +182,8 @@ pic_dump_code(pic_state *pic, pic_code c)
   }
 }
 
-inline void
-pic_dump_irep(pic_state *pic, struct pic_irep *irep)
+static inline void
+pic_dump_irep(struct pic_irep *irep)
 {
   unsigned i;
 
@@ -197,11 +195,11 @@ pic_dump_irep(pic_state *pic, struct pic_irep *irep)
   }
   for (i = 0; i < irep->clen; ++i) {
     printf("%02x ", i);
-    pic_dump_code(pic, irep->code[i]);
+    pic_dump_code(irep->code[i]);
   }
 
   for (i = 0; i < irep->ilen; ++i) {
-    pic_dump_irep(pic, irep->irep[i]);
+    pic_dump_irep(irep->irep[i]);
   }
 }
 
diff --git a/src/codegen.c b/src/codegen.c
index 2c9230be..7916e16b 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -1460,7 +1460,7 @@ pic_compile(pic_state *pic, pic_value obj)
   irep = pic_codegen(pic, obj);
 #if DEBUG
   fprintf(stdout, "## codegen completed\n");
-  pic_dump_irep(pic, irep);
+  pic_dump_irep(irep);
 #endif
 
 #if DEBUG
diff --git a/src/vm.c b/src/vm.c
index 31b4028b..8963f686 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -443,7 +443,7 @@ pic_apply_argv(pic_state *pic, struct pic_proc *proc, size_t argc, ...)
 }
 
 #if VM_DEBUG
-# define OPCODE_EXEC_HOOK pic_dump_code(pic, c)
+# define OPCODE_EXEC_HOOK pic_dump_code(c)
 #else
 # define OPCODE_EXEC_HOOK ((void)0)
 #endif
@@ -654,7 +654,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
       puts(")");
       if (! pic_proc_func_p(proc)) {
 	printf("  irep = ");
-	pic_dump_irep(pic, proc->u.irep);
+	pic_dump_irep(proc->u.irep);
       }
       else {
 	printf("  cfunc = %p\n", (void *)proc->u.func.f);