diff --git a/src/hb-wasm-api-blob.hh b/src/hb-wasm-api-blob.hh
index 8a8f9e2a9..e9aff8968 100644
--- a/src/hb-wasm-api-blob.hh
+++ b/src/hb-wasm-api-blob.hh
@@ -35,11 +35,10 @@ void
 blob_free (HB_WASM_EXEC_ENV
 	   ptr_t(blob_t) blobptr)
 {
-  if (unlikely (!validate_app_addr (blobptr, sizeof (blob_t))))
+  HB_STRUCT_TYPE (blob_t, blob);
+  if (unlikely (!blob))
     return;
 
-  blob_t *blob = (blob_t *) addr_app_to_native (blobptr);
-
   module_free (blob->data);
 }
 
diff --git a/src/hb-wasm-api-buffer.hh b/src/hb-wasm-api-buffer.hh
index 139899a8f..949195167 100644
--- a/src/hb-wasm-api-buffer.hh
+++ b/src/hb-wasm-api-buffer.hh
@@ -37,11 +37,10 @@ void
 buffer_contents_free (HB_WASM_EXEC_ENV
 		      ptr_t(buffer_contents_t) contentsptr)
 {
-  if (unlikely (!validate_app_addr (contentsptr, sizeof (buffer_contents_t))))
+  HB_STRUCT_TYPE (buffer_contents_t, contents);
+  if (unlikely (!contents))
     return;
 
-  buffer_contents_t *contents = (buffer_contents_t *) addr_app_to_native (contentsptr);
-
   module_free (contents->info);
   module_free (contents->pos);
 }
diff --git a/src/hb-wasm-api.hh b/src/hb-wasm-api.hh
index a005024c9..4fc95fd94 100644
--- a/src/hb-wasm-api.hh
+++ b/src/hb-wasm-api.hh
@@ -68,6 +68,7 @@ HB_INTERNAL extern hb_user_data_key_t _hb_wasm_ref_type_key;
 		  (void *) hb_wasm_ref_type_##obj)) \
       obj = hb_##obj##_get_empty (); \
   } HB_STMT_END
+
 #define HB_OBJ2REF(obj) \
   uint32_t obj##ref = nullref; \
   HB_STMT_START { \
@@ -90,5 +91,13 @@ HB_INTERNAL extern hb_user_data_key_t _hb_wasm_ref_type_key;
   } \
   type &name = *_name_ptr
 
+#define HB_STRUCT_TYPE(type, name) \
+  type *name = nullptr; \
+  HB_STMT_START { \
+    if (likely (wasm_runtime_validate_app_addr (module_inst, \
+						name##ptr, sizeof (type)))) \
+      name = (type *) wasm_runtime_addr_app_to_native (module_inst, name##ptr); \
+  } HB_STMT_END
+
 
 #endif /* HB_WASM_API_HH */