diff --git a/upb/bindings/lua/msg.c b/upb/bindings/lua/msg.c
index 41163bca23..e468ace285 100644
--- a/upb/bindings/lua/msg.c
+++ b/upb/bindings/lua/msg.c
@@ -434,7 +434,7 @@ static upb_msgval lupb_tomsgval(lua_State *L, upb_fieldtype_t type, int narg,
     case UPB_TYPE_BYTES: {
       size_t len;
       const char *ptr = lupb_checkstring(L, narg, &len);
-      return upb_msgval_str(ptr, len);
+      return upb_msgval_makestr(ptr, len);
     }
     case UPB_TYPE_MESSAGE:
       UPB_ASSERT(lmsgclass);
@@ -1014,7 +1014,7 @@ static int lupb_msg_index(lua_State *L) {
         if (upb_msg_has(lmsg->msg, field_index, l)) {
           upb_msgval val = upb_msg_get(lmsg->msg, field_index, l);
           lua_pop(L, 1);
-          lua_pushlstring(L, val.str.ptr, val.str.len);
+          lua_pushlstring(L, val.str.data, val.str.size);
           lupb_uservalseti(L, 1, lupb_fieldindex(f), -1);
         }
       }
diff --git a/upb/msg.c b/upb/msg.c
index 850e86efe0..59f7c44fdc 100644
--- a/upb/msg.c
+++ b/upb/msg.c
@@ -135,7 +135,7 @@ static upb_msgval upb_msgval_fromdefault(const upb_fielddef *f) {
       case UPB_TYPE_BYTES: {
         size_t len;
         const char *ptr = upb_fielddef_defaultstr(f, &len);
-        return upb_msgval_str(ptr, len);
+        return upb_msgval_makestr(ptr, len);
       }
       case UPB_TYPE_MESSAGE:
         return upb_msgval_msg(NULL);
@@ -423,9 +423,9 @@ void *upb_msg_startstr(void *msg, const void *hd, size_t size_hint) {
 
   val = upb_msgval_read(msg, ofs, upb_msgval_sizeof(UPB_TYPE_STRING));
 
-  upb_free(alloc, (void*)val.str.ptr);
-  val.str.ptr = NULL;
-  val.str.len = 0;
+  upb_free(alloc, (void*)val.str.data);
+  val.str.data = NULL;
+  val.str.size = 0;
 
   upb_msgval_write(msg, ofs, val, upb_msgval_sizeof(UPB_TYPE_STRING));
   return msg;
@@ -441,15 +441,15 @@ size_t upb_msg_str(void *msg, const void *hd, const char *ptr, size_t size,
 
   val = upb_msgval_read(msg, ofs, upb_msgval_sizeof(UPB_TYPE_STRING));
 
-  newsize = val.str.len + size;
-  val.str.ptr = upb_realloc(alloc, (void*)val.str.ptr, val.str.len, newsize);
+  newsize = val.str.size + size;
+  val.str.data = upb_realloc(alloc, (void*)val.str.data, val.str.size, newsize);
 
-  if (!val.str.ptr) {
+  if (!val.str.data) {
     return false;
   }
 
-  memcpy((char*)val.str.ptr + val.str.len, ptr, size);
-  val.str.len = newsize;
+  memcpy((char*)val.str.data + val.str.size, ptr, size);
+  val.str.size = newsize;
   upb_msgval_write(msg, ofs, val, upb_msgval_sizeof(UPB_TYPE_STRING));
   return size;
 }
@@ -540,7 +540,7 @@ static bool upb_visitor_hasfield(const upb_msg *msg, const upb_fielddef *f,
         return upb_msgval_getuint64(val) != 0;
       case UPB_TYPE_STRING:
       case UPB_TYPE_BYTES:
-        return upb_msgval_getstr(val) && upb_msgval_getstrlen(val) > 0;
+        return upb_msgval_getstr(val).size > 0;
       case UPB_TYPE_MESSAGE:
         return upb_msgval_getmsg(val) != NULL;
     }
@@ -899,8 +899,8 @@ static void upb_map_tokey(upb_fieldtype_t type, upb_msgval *key,
   switch (type) {
     case UPB_TYPE_STRING:
       /* Point to string data of the input key. */
-      *out_key = key->str.ptr;
-      *out_len = key->str.len;
+      *out_key = key->str.data;
+      *out_len = key->str.size;
       return;
     case UPB_TYPE_BOOL:
     case UPB_TYPE_INT32:
@@ -925,7 +925,7 @@ static upb_msgval upb_map_fromkey(upb_fieldtype_t type, const char *key,
                                   size_t len) {
   switch (type) {
     case UPB_TYPE_STRING:
-      return upb_msgval_str(key, len);
+      return upb_msgval_makestr(key, len);
     case UPB_TYPE_BOOL:
     case UPB_TYPE_INT32:
     case UPB_TYPE_UINT32:
diff --git a/upb/msg.h b/upb/msg.h
index 1d888b8266..c5d1cf4a25 100644
--- a/upb/msg.h
+++ b/upb/msg.h
@@ -110,6 +110,23 @@ const upb_visitorplan *upb_msgfactory_getvisitorplan(upb_msgfactory *f,
                                                      const upb_handlers *h);
 
 
+/** upb_stringview ************************************************************/
+
+typedef struct {
+  const char *data;
+  size_t size;
+} upb_stringview;
+
+UPB_INLINE upb_stringview upb_stringview_make(const char *data, size_t size) {
+  upb_stringview ret;
+  ret.data = data;
+  ret.size = size;
+  return ret;
+}
+
+#define UPB_STRINGVIEW_INIT(ptr, len) {ptr, len}
+
+
 /** upb_msgval ****************************************************************/
 
 /* A union representing all possible protobuf values.  Used for generic get/set
@@ -127,10 +144,7 @@ typedef union {
   const upb_msg* msg;
   const upb_array* arr;
   const void* ptr;
-  struct {
-    const char *ptr;
-    size_t len;
-  } str;
+  upb_stringview str;
 } upb_msgval;
 
 #define ACCESSORS(name, membername, ctype) \
@@ -157,22 +171,12 @@ ACCESSORS(map,    map, const upb_map*)
 ACCESSORS(msg,    msg, const upb_msg*)
 ACCESSORS(ptr,    ptr, const void*)
 ACCESSORS(arr,    arr, const upb_array*)
+ACCESSORS(str,    str, upb_stringview)
 
 #undef ACCESSORS
 
-UPB_INLINE upb_msgval upb_msgval_str(const char *ptr, size_t len) {
-  upb_msgval ret;
-  ret.str.ptr = ptr;
-  ret.str.len = len;
-  return ret;
-}
-
-UPB_INLINE const char* upb_msgval_getstr(upb_msgval val) {
-  return val.str.ptr;
-}
-
-UPB_INLINE size_t upb_msgval_getstrlen(upb_msgval val) {
-  return val.str.len;
+UPB_INLINE upb_msgval upb_msgval_makestr(const char *data, size_t size) {
+  return upb_msgval_str(upb_stringview_make(data, size));
 }