diff --git a/cmake/google/protobuf/descriptor.upb.c b/cmake/google/protobuf/descriptor.upb.c
index ef4f876a65..21dbcaddbe 100644
--- a/cmake/google/protobuf/descriptor.upb.c
+++ b/cmake/google/protobuf/descriptor.upb.c
@@ -184,7 +184,7 @@ static const upb_MiniTable_Field google_protobuf_EnumDescriptorProto__fields[5]
 const upb_MiniTable google_protobuf_EnumDescriptorProto_msginit = {
   &google_protobuf_EnumDescriptorProto_submsgs[0],
   &google_protobuf_EnumDescriptorProto__fields[0],
-  UPB_SIZE(32, 64), 5, upb_ExtMode_NonExtendable, 5, 255, 0,
+  UPB_SIZE(32, 56), 5, upb_ExtMode_NonExtendable, 5, 255, 0,
 };
 
 static const upb_MiniTable_Field google_protobuf_EnumDescriptorProto_EnumReservedRange__fields[2] = {
@@ -228,7 +228,7 @@ static const upb_MiniTable_Field google_protobuf_ServiceDescriptorProto__fields[
 const upb_MiniTable google_protobuf_ServiceDescriptorProto_msginit = {
   &google_protobuf_ServiceDescriptorProto_submsgs[0],
   &google_protobuf_ServiceDescriptorProto__fields[0],
-  UPB_SIZE(24, 48), 3, upb_ExtMode_NonExtendable, 3, 255, 0,
+  UPB_SIZE(24, 40), 3, upb_ExtMode_NonExtendable, 3, 255, 0,
 };
 
 static const upb_MiniTable_Sub google_protobuf_MethodDescriptorProto_submsgs[1] = {
@@ -420,7 +420,7 @@ static const upb_MiniTable_Field google_protobuf_UninterpretedOption__fields[7]
 const upb_MiniTable google_protobuf_UninterpretedOption_msginit = {
   &google_protobuf_UninterpretedOption_submsgs[0],
   &google_protobuf_UninterpretedOption__fields[0],
-  UPB_SIZE(64, 96), 7, upb_ExtMode_NonExtendable, 0, 255, 0,
+  UPB_SIZE(64, 88), 7, upb_ExtMode_NonExtendable, 0, 255, 0,
 };
 
 static const upb_MiniTable_Field google_protobuf_UninterpretedOption_NamePart__fields[2] = {
@@ -431,7 +431,7 @@ static const upb_MiniTable_Field google_protobuf_UninterpretedOption_NamePart__f
 const upb_MiniTable google_protobuf_UninterpretedOption_NamePart_msginit = {
   NULL,
   &google_protobuf_UninterpretedOption_NamePart__fields[0],
-  UPB_SIZE(16, 32), 2, upb_ExtMode_NonExtendable, 2, 255, 2,
+  UPB_SIZE(16, 24), 2, upb_ExtMode_NonExtendable, 2, 255, 2,
 };
 
 static const upb_MiniTable_Sub google_protobuf_SourceCodeInfo_submsgs[1] = {
@@ -486,7 +486,7 @@ static const upb_MiniTable_Field google_protobuf_GeneratedCodeInfo_Annotation__f
 const upb_MiniTable google_protobuf_GeneratedCodeInfo_Annotation_msginit = {
   NULL,
   &google_protobuf_GeneratedCodeInfo_Annotation__fields[0],
-  UPB_SIZE(24, 48), 4, upb_ExtMode_NonExtendable, 4, 255, 0,
+  UPB_SIZE(24, 40), 4, upb_ExtMode_NonExtendable, 4, 255, 0,
 };
 
 static const upb_MiniTable *messages_layout[27] = {
diff --git a/upb/upb.h b/upb/upb.h
index 45000ffdaf..5c500fe5f5 100644
--- a/upb/upb.h
+++ b/upb/upb.h
@@ -227,7 +227,7 @@ UPB_INLINE void* upb_Arena_Realloc(upb_Arena* a, void* ptr, size_t oldsize,
                                    size_t size) {
   _upb_ArenaHead* h = (_upb_ArenaHead*)a;
   char* ch_ptr = (char*)ptr;
-  oldsize = UPB_ALIGN_MALLOC(size);
+  oldsize = UPB_ALIGN_MALLOC(oldsize);
   size = UPB_ALIGN_MALLOC(size);
   if (ch_ptr + oldsize == h->ptr) {
     if ((size_t)(h->end - ch_ptr) >= size) {
diff --git a/upbc/protoc-gen-upb.cc b/upbc/protoc-gen-upb.cc
index 62ce9a7850..b701640110 100644
--- a/upbc/protoc-gen-upb.cc
+++ b/upbc/protoc-gen-upb.cc
@@ -1431,11 +1431,11 @@ void WriteMessage(const protobuf::Descriptor* message, const FileLayout& layout,
       FieldNumberOrder(message);
   assert(field_number_order.size() == mt_32->field_count);
   assert(field_number_order.size() == mt_64->field_count);
-  if (!field_number_order.empty()) {
+  if (mt_64->field_count > 0) {
     std::string fields_array_name = msg_name + "__fields";
     fields_array_ref = "&" + fields_array_name + "[0]";
     output("static const upb_MiniTable_Field $0[$1] = {\n", fields_array_name,
-           field_number_order.size());
+           mt_64->field_count());
     for (int i = 0; i < static_cast<int>(field_number_order.size()); i++) {
       auto field = field_number_order[i];
       int sublayout_index = 0;