diff --git a/common.mk b/common.mk
index 339a010c8e..2fa479fa9b 100644
--- a/common.mk
+++ b/common.mk
@@ -1519,6 +1519,7 @@ debug.$(OBJEXT): {$(VPATH)}ruby_assert.h
 debug.$(OBJEXT): {$(VPATH)}ruby_atomic.h
 debug.$(OBJEXT): {$(VPATH)}st.h
 debug.$(OBJEXT): {$(VPATH)}subst.h
+debug.$(OBJEXT): {$(VPATH)}symbol.h
 debug.$(OBJEXT): {$(VPATH)}thread_$(THREAD_MODEL).h
 debug.$(OBJEXT): {$(VPATH)}thread_native.h
 debug.$(OBJEXT): {$(VPATH)}util.h
diff --git a/debug.c b/debug.c
index a670716b77..6483ccd562 100644
--- a/debug.c
+++ b/debug.c
@@ -15,6 +15,7 @@
 #include "vm_debug.h"
 #include "eval_intern.h"
 #include "vm_core.h"
+#include "symbol.h"
 #include "id.h"
 
 /* for gdb */
@@ -59,6 +60,7 @@ const union {
     } various;
     enum imemo_type             imemo_types;
     enum {RUBY_IMEMO_MASK = IMEMO_MASK} imemo_mask;
+    struct RSymbol *symbol_ptr;
 } ruby_dummy_gdb_enums;
 
 const SIGNED_VALUE RUBY_NODE_LMASK = NODE_LMASK;