diff --git a/lib/cell.h b/lib/cell.h
index f07407bf..0ce4c56b 100644
--- a/lib/cell.h
+++ b/lib/cell.h
@@ -5,6 +5,8 @@
 
 #include "toywasm_config.h"
 
+#include "platform.h"
+
 enum valtype;
 struct localtype;
 struct resulttype;
@@ -20,7 +22,7 @@ struct cell {
 #endif
 };
 
-uint32_t valtype_cellsize(enum valtype t);
+uint32_t valtype_cellsize(enum valtype t) __constfunc;
 
 uint32_t resulttype_cellidx(const struct resulttype *rt, uint32_t idx,
                             uint32_t *cszp);
diff --git a/lib/context.h b/lib/context.h
index d30f1890..c6552d35 100644
--- a/lib/context.h
+++ b/lib/context.h
@@ -4,6 +4,7 @@
 #include "toywasm_config.h"
 
 #include "cell.h"
+#include "platform.h"
 #include "report.h"
 #include "vec.h"
 
@@ -248,7 +249,7 @@ int frame_enter(struct exec_context *ctx, struct instance *inst,
 void frame_clear(struct funcframe *frame);
 void frame_exit(struct exec_context *ctx);
 struct cell *frame_locals(struct exec_context *ctx,
-                          const struct funcframe *frame);
+                          const struct funcframe *frame) __purefunc;
 void exec_context_init(struct exec_context *ctx, struct instance *inst);
 void exec_context_clear(struct exec_context *ctx);
 void exec_context_print_stats(struct exec_context *ctx);
diff --git a/lib/type.h b/lib/type.h
index 5fb16b3d..ccfd483e 100644
--- a/lib/type.h
+++ b/lib/type.h
@@ -9,6 +9,7 @@
 #include "bitmap.h"
 #include "cell.h"
 #include "lock.h"
+#include "platform.h"
 #include "vec.h"
 
 #define WASM_MAGIC 0x6d736100
@@ -462,10 +463,10 @@ struct import_object {
         struct import_object *next;
 };
 
-bool is_numtype(enum valtype vt);
-bool is_vectype(enum valtype vt);
-bool is_reftype(enum valtype vt);
-bool is_valtype(enum valtype vt);
+bool is_numtype(enum valtype vt) __constfunc;
+bool is_vectype(enum valtype vt) __constfunc;
+bool is_reftype(enum valtype vt) __constfunc;
+bool is_valtype(enum valtype vt) __constfunc;
 int compare_resulttype(const struct resulttype *a, const struct resulttype *b);
 int compare_functype(const struct functype *a, const struct functype *b);
 int compare_name(const struct name *a, const struct name *b);