diff --git a/build_defs/upb.patch b/build_defs/upb.patch
index 809fb70..ec1f28b 100644
--- a/build_defs/upb.patch
+++ b/build_defs/upb.patch
@@ -9,4 +9,22 @@
  # end:github_only
  
  def _upbc(stage):
- 
\ No newline at end of file
+ 
+--- cmake/build_defs.bzl
++++ cmake/build_defs.bzl
+@@ -25,7 +25,7 @@
+ 
+ """Bazel support functions related to CMake support."""
+ 
+-def staleness_test(name, outs, generated_pattern, target_files = None, **kwargs):
++def staleness_test(name, outs, generated_pattern, target_files = None, tags = [], **kwargs):
+     """Tests that checked-in file(s) match the contents of generated file(s).
+ 
+     The resulting test will verify that all output files exist and have the
+@@ -72,5 +72,6 @@ def staleness_test(name, outs, generated_pattern, target_files = None, **kwargs)
+         deps = [
+             Label("//cmake:staleness_test_lib"),
+         ],
++        tags = ["staleness_test"] + tags,
+         **kwargs
+     )
diff --git a/php/ext/google/protobuf/php-upb.c b/php/ext/google/protobuf/php-upb.c
index 2dac3ad..ef95724 100644
--- a/php/ext/google/protobuf/php-upb.c
+++ b/php/ext/google/protobuf/php-upb.c
@@ -641,12 +641,14 @@
     [kUpb_FieldType_Bytes] = _upb_mapsorter_cmpstr,
 };
 
-static bool _upb_mapsorter_resize(_upb_mapsorter* s, _upb_sortedmap* sorted,
-                                  int size) {
+bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
+                            const upb_Map* map, _upb_sortedmap* sorted) {
+  int map_size = _upb_Map_Size(map);
   sorted->start = s->size;
   sorted->pos = sorted->start;
-  sorted->end = sorted->start + size;
+  sorted->end = sorted->start + map_size;
 
+  // Grow s->entries if necessary.
   if (sorted->end > s->cap) {
     s->cap = upb_Log2CeilingSize(sorted->end);
     s->entries = realloc(s->entries, s->cap * sizeof(*s->entries));
@@ -654,17 +656,9 @@
   }
 
   s->size = sorted->end;
-  return true;
-}
-
-bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
-                            const upb_Map* map, _upb_sortedmap* sorted) {
-  int map_size = _upb_Map_Size(map);
-
-  if (!_upb_mapsorter_resize(s, sorted, map_size)) return false;
 
   // Copy non-empty entries from the table to s->entries.
-  const void** dst = &s->entries[sorted->start];
+  upb_tabent const** dst = &s->entries[sorted->start];
   const upb_tabent* src = map->table.t.entries;
   const upb_tabent* end = src + upb_table_size(&map->table.t);
   for (; src < end; src++) {
@@ -680,29 +674,6 @@
         compar[key_type]);
   return true;
 }
-
-static int _upb_mapsorter_cmpext(const void* _a, const void* _b) {
-  const upb_Message_Extension* const* a = _a;
-  const upb_Message_Extension* const* b = _b;
-  uint32_t a_num = (*a)->ext->field.number;
-  uint32_t b_num = (*b)->ext->field.number;
-  assert(a_num != b_num);
-  return a_num < b_num ? -1 : 1;
-}
-
-bool _upb_mapsorter_pushexts(_upb_mapsorter* s,
-                             const upb_Message_Extension* exts, size_t count,
-                             _upb_sortedmap* sorted) {
-  if (!_upb_mapsorter_resize(s, sorted, count)) return false;
-
-  for (size_t i = 0; i < count; i++) {
-    s->entries[sorted->start + i] = &exts[i];
-  }
-
-  qsort(&s->entries[sorted->start], count, sizeof(*s->entries),
-        _upb_mapsorter_cmpext);
-  return true;
-}
 /* This file was generated by upbc (the upb compiler) from the input
  * file:
  *
@@ -2254,7 +2225,7 @@
   n = len + 1;
   p = upb_Arena_Malloc(a, n);
   if (p) {
-    if (len != 0) memcpy(p, s, len);
+    memcpy(p, s, len);
     p[len] = 0;
   }
   return p;
@@ -7590,27 +7561,9 @@
   _upb_DefBuilder_FailJmp(ctx);
 }
 
-// Verify a relative identifier string. The loop is branchless for speed.
-static void _upb_DefBuilder_CheckIdentNotFull(upb_DefBuilder* ctx,
-                                              upb_StringView name) {
-  bool good = name.size > 0;
-
-  for (size_t i = 0; i < name.size; i++) {
-    const char c = name.data[i];
-    const char d = c | 0x20;  // force lowercase
-    const bool is_alpha = (('a' <= d) & (d <= 'z')) | (c == '_');
-    const bool is_numer = ('0' <= c) & (c <= '9') & (i != 0);
-
-    good &= is_alpha | is_numer;
-  }
-
-  if (!good) _upb_DefBuilder_CheckIdentSlow(ctx, name, false);
-}
-
 const char* _upb_DefBuilder_MakeFullName(upb_DefBuilder* ctx,
                                          const char* prefix,
                                          upb_StringView name) {
-  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
   if (prefix) {
     // ret = prefix + '.' + name;
     size_t n = strlen(prefix);
@@ -7726,7 +7679,7 @@
   return true;
 }
 
-static int TryGetHexDigit(const char** src, const char* end) {
+static char TryGetHexDigit(const char** src, const char* end) {
   char ch;
   if (!TryGetChar(src, end, &ch)) return -1;
   if ('0' <= ch && ch <= '9') {
@@ -7743,10 +7696,10 @@
 static char upb_DefBuilder_ParseHexEscape(upb_DefBuilder* ctx,
                                           const upb_FieldDef* f,
                                           const char** src, const char* end) {
-  int hex_digit = TryGetHexDigit(src, end);
+  char hex_digit = TryGetHexDigit(src, end);
   if (hex_digit < 0) {
     _upb_DefBuilder_Errf(
-        ctx, "\\x must be followed by at least one hex digit (field='%s')",
+        ctx, "\\x cannot be followed by non-hex digit in field '%s' default",
         upb_FieldDef_FullName(f));
     return 0;
   }
@@ -7922,7 +7875,7 @@
 }
 
 bool _upb_DefPool_InsertExt(upb_DefPool* s, const upb_MiniTableExtension* ext,
-                            const upb_FieldDef* f) {
+                            upb_FieldDef* f) {
   return upb_inttable_insert(&s->exts, (uintptr_t)ext, upb_value_constptr(f),
                              s->arena);
 }
@@ -8154,6 +8107,12 @@
     const upb_MiniTableFile* layout, upb_Status* status) {
   const upb_StringView name = UPB_DESC(FileDescriptorProto_name)(file_proto);
 
+  if (name.size == 0) {
+    upb_Status_SetErrorFormat(status,
+                              "missing name in google_protobuf_FileDescriptorProto");
+    return NULL;
+  }
+
   // Determine whether we already know about this file.
   {
     upb_value v;
@@ -8545,6 +8504,7 @@
   e->file = _upb_DefBuilder_File(ctx);
 
   name = UPB_DESC(EnumDescriptorProto_name)(enum_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   e->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
   _upb_DefBuilder_Add(ctx, e->full_name,
@@ -9354,14 +9314,7 @@
   }
 
   const upb_StringView name = UPB_DESC(FieldDescriptorProto_name)(field_proto);
-
-  f->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
-  f->label_ = (int)UPB_DESC(FieldDescriptorProto_label)(field_proto);
-  f->number_ = UPB_DESC(FieldDescriptorProto_number)(field_proto);
-  f->is_proto3_optional =
-      UPB_DESC(FieldDescriptorProto_proto3_optional)(field_proto);
-  f->msgdef = m;
-  f->scope.oneof = NULL;
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   f->has_json_name = UPB_DESC(FieldDescriptorProto_has_json_name)(field_proto);
   if (f->has_json_name) {
@@ -9373,6 +9326,14 @@
   }
   if (!f->json_name) _upb_DefBuilder_OomErr(ctx);
 
+  f->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
+  f->label_ = (int)UPB_DESC(FieldDescriptorProto_label)(field_proto);
+  f->number_ = UPB_DESC(FieldDescriptorProto_number)(field_proto);
+  f->is_proto3_optional =
+      UPB_DESC(FieldDescriptorProto_proto3_optional)(field_proto);
+  f->msgdef = m;
+  f->scope.oneof = NULL;
+
   const bool has_type = UPB_DESC(FieldDescriptorProto_has_type)(field_proto);
   const bool has_type_name =
       UPB_DESC(FieldDescriptorProto_has_type_name)(field_proto);
@@ -9502,24 +9463,19 @@
   }
 
   _upb_MessageDef_InsertField(ctx, m, f);
-}
 
-upb_FieldDef* _upb_Extensions_New(
-    upb_DefBuilder* ctx, int n,
-    const UPB_DESC(FieldDescriptorProto) * const* protos, const char* prefix,
-    upb_MessageDef* m) {
-  _upb_DefType_CheckPadding(sizeof(upb_FieldDef));
-  upb_FieldDef* defs =
-      (upb_FieldDef*)_upb_DefBuilder_Alloc(ctx, sizeof(upb_FieldDef) * n);
+  if (!ctx->layout) return;
 
-  for (int i = 0; i < n; i++) {
-    upb_FieldDef* f = &defs[i];
-
-    _upb_FieldDef_CreateExt(ctx, prefix, protos[i], m, f);
-    f->index_ = i;
+  const upb_MiniTable* mt = upb_MessageDef_MiniTable(m);
+  const upb_MiniTableField* fields = mt->fields;
+  for (int i = 0; i < mt->field_count; i++) {
+    if (fields[i].number == f->number_) {
+      f->layout_index = i;
+      return;
+    }
   }
 
-  return defs;
+  UPB_ASSERT(false);  // It should be impossible to reach this point.
 }
 
 upb_FieldDef* _upb_FieldDefs_New(
@@ -9530,23 +9486,28 @@
   upb_FieldDef* defs =
       (upb_FieldDef*)_upb_DefBuilder_Alloc(ctx, sizeof(upb_FieldDef) * n);
 
-  uint32_t previous = 0;
-  for (int i = 0; i < n; i++) {
-    upb_FieldDef* f = &defs[i];
+  // If we are creating extensions then is_sorted will be NULL.
+  // If we are not creating extensions then is_sorted will be non-NULL.
+  if (is_sorted) {
+    uint32_t previous = 0;
+    for (int i = 0; i < n; i++) {
+      upb_FieldDef* f = &defs[i];
 
-    _upb_FieldDef_CreateNotExt(ctx, prefix, protos[i], m, f);
-    f->index_ = i;
-    if (!ctx->layout) {
-      // Speculate that the def fields are sorted.  We will always sort the
-      // MiniTable fields, so if defs are sorted then indices will match.
-      //
-      // If this is incorrect, we will overwrite later.
-      f->layout_index = i;
+      _upb_FieldDef_CreateNotExt(ctx, prefix, protos[i], m, f);
+      f->index_ = i;
+      if (!ctx->layout) f->layout_index = i;
+
+      const uint32_t current = f->number_;
+      if (previous > current) *is_sorted = false;
+      previous = current;
     }
+  } else {
+    for (int i = 0; i < n; i++) {
+      upb_FieldDef* f = &defs[i];
 
-    const uint32_t current = f->number_;
-    if (previous > current) *is_sorted = false;
-    previous = current;
+      _upb_FieldDef_CreateExt(ctx, prefix, protos[i], m, f);
+      f->index_ = i;
+    }
   }
 
   return defs;
@@ -9602,9 +9563,6 @@
   return (v1 < v2) ? -1 : (v1 > v2);
 }
 
-// _upb_FieldDefs_Sorted() is mostly a pure function of its inputs, but has one
-// critical side effect that we depend on: it sets layout_index appropriately
-// for non-sorted lists of fields.
 const upb_FieldDef** _upb_FieldDefs_Sorted(const upb_FieldDef* f, int n,
                                            upb_Arena* a) {
   // TODO(salo): Replace this arena alloc with a persistent scratch buffer.
@@ -9662,10 +9620,7 @@
         "field number %u in extension %s has no extension range in message %s",
         (unsigned)f->number_, f->full_name, upb_MessageDef_FullName(m));
   }
-}
 
-void _upb_FieldDef_BuildMiniTableExtension(upb_DefBuilder* ctx,
-                                           const upb_FieldDef* f) {
   const upb_MiniTableExtension* ext = _upb_FieldDef_ExtensionMiniTable(f);
 
   if (ctx->layout) {
@@ -9684,8 +9639,8 @@
       sub.subenum = _upb_EnumDef_MiniTable(f->sub.enumdef);
     }
     bool ok2 = upb_MiniTableExtension_Build(desc.data, desc.size, mut_ext,
-                                            upb_MessageDef_MiniTable(f->msgdef),
-                                            sub, ctx->status);
+                                            upb_MessageDef_MiniTable(m), sub,
+                                            ctx->status);
     if (!ok2) _upb_DefBuilder_Errf(ctx, "Could not build extension mini table");
   }
 
@@ -9742,7 +9697,6 @@
   const UPB_DESC(FileOptions) * opts;
   const char* name;
   const char* package;
-  const char* edition;
 
   const upb_FileDef** deps;
   const int32_t* public_deps;
@@ -9779,10 +9733,6 @@
   return f->package ? f->package : "";
 }
 
-const char* upb_FileDef_Edition(const upb_FileDef* f) {
-  return f->edition ? f->edition : "";
-}
-
 const char* _upb_FileDef_RawPackage(const upb_FileDef* f) { return f->package; }
 
 upb_Syntax upb_FileDef_Syntax(const upb_FileDef* f) { return f->syntax; }
@@ -9930,14 +9880,13 @@
     }
   }
 
-  upb_StringView name = UPB_DESC(FileDescriptorProto_name)(file_proto);
-  file->name = strviewdup(ctx, name);
-  if (strlen(file->name) != name.size) {
-    _upb_DefBuilder_Errf(ctx, "File name contained embedded NULL");
+  if (!UPB_DESC(FileDescriptorProto_has_name)(file_proto)) {
+    _upb_DefBuilder_Errf(ctx, "File has no name");
   }
 
-  upb_StringView package = UPB_DESC(FileDescriptorProto_package)(file_proto);
+  file->name = strviewdup(ctx, UPB_DESC(FileDescriptorProto_name)(file_proto));
 
+  upb_StringView package = UPB_DESC(FileDescriptorProto_package)(file_proto);
   if (package.size) {
     _upb_DefBuilder_CheckIdentFull(ctx, package);
     file->package = strviewdup(ctx, package);
@@ -9945,18 +9894,6 @@
     file->package = NULL;
   }
 
-  upb_StringView edition = UPB_DESC(FileDescriptorProto_edition)(file_proto);
-
-  if (edition.size == 0) {
-    file->edition = NULL;
-  } else {
-    // TODO(b/267770604): How should we validate this?
-    file->edition = strviewdup(ctx, edition);
-    if (strlen(file->edition) != edition.size) {
-      _upb_DefBuilder_Errf(ctx, "Edition name contained embedded NULL");
-    }
-  }
-
   if (UPB_DESC(FileDescriptorProto_has_syntax)(file_proto)) {
     upb_StringView syntax = UPB_DESC(FileDescriptorProto_syntax)(file_proto);
 
@@ -10025,7 +9962,8 @@
   // Create extensions.
   exts = UPB_DESC(FileDescriptorProto_extension)(file_proto, &n);
   file->top_lvl_ext_count = n;
-  file->top_lvl_exts = _upb_Extensions_New(ctx, n, exts, file->package, NULL);
+  file->top_lvl_exts =
+      _upb_FieldDefs_New(ctx, n, exts, file->package, NULL, NULL);
 
   // Create messages.
   msgs = UPB_DESC(FileDescriptorProto_message_type)(file_proto, &n);
@@ -10049,19 +9987,11 @@
     _upb_FieldDef_Resolve(ctx, file->package, f);
   }
 
-  for (int i = 0; i < file->top_lvl_msg_count; i++) {
-    upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
-    _upb_MessageDef_CreateMiniTable(ctx, (upb_MessageDef*)m);
-  }
-
-  for (int i = 0; i < file->top_lvl_ext_count; i++) {
-    upb_FieldDef* f = (upb_FieldDef*)upb_FileDef_TopLevelExtension(file, i);
-    _upb_FieldDef_BuildMiniTableExtension(ctx, f);
-  }
-
-  for (int i = 0; i < file->top_lvl_msg_count; i++) {
-    upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
-    _upb_MessageDef_LinkMiniTable(ctx, m);
+  if (!ctx->layout) {
+    for (int i = 0; i < file->top_lvl_msg_count; i++) {
+      upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
+      _upb_MessageDef_LinkMiniTable(ctx, m);
+    }
   }
 
   if (file->ext_count) {
@@ -10574,8 +10504,6 @@
 static upb_MiniTable* _upb_MessageDef_MakeMiniTable(upb_DefBuilder* ctx,
                                                     const upb_MessageDef* m) {
   upb_StringView desc;
-  // Note: this will assign layout_index for fields, so upb_FieldDef_MiniTable()
-  // is safe to call only after this call.
   bool ok = upb_MessageDef_MiniDescriptorEncode(m, ctx->tmp_arena, &desc);
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 
@@ -10595,6 +10523,23 @@
     _upb_FieldDef_Resolve(ctx, m->full_name, f);
   }
 
+  if (!ctx->layout) {
+    m->layout = _upb_MessageDef_MakeMiniTable(ctx, m);
+    if (!m->layout) _upb_DefBuilder_OomErr(ctx);
+  }
+
+#ifndef NDEBUG
+  for (int i = 0; i < m->field_count; i++) {
+    const upb_FieldDef* f = upb_MessageDef_Field(m, i);
+    const int layout_index = _upb_FieldDef_LayoutIndex(f);
+    UPB_ASSERT(layout_index < m->layout->field_count);
+    const upb_MiniTableField* mt_f = &m->layout->fields[layout_index];
+    UPB_ASSERT(upb_FieldDef_Type(f) == upb_MiniTableField_Type(mt_f));
+    UPB_ASSERT(upb_FieldDef_HasPresence(f) ==
+               upb_MiniTableField_HasPresence(mt_f));
+  }
+#endif
+
   m->in_message_set = false;
   for (int i = 0; i < upb_MessageDef_NestedExtensionCount(m); i++) {
     upb_FieldDef* ext = (upb_FieldDef*)upb_MessageDef_NestedExtension(m, i);
@@ -10657,39 +10602,8 @@
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 }
 
-void _upb_MessageDef_CreateMiniTable(upb_DefBuilder* ctx, upb_MessageDef* m) {
-  if (ctx->layout == NULL) {
-    m->layout = _upb_MessageDef_MakeMiniTable(ctx, m);
-  } else {
-    UPB_ASSERT(ctx->msg_count < ctx->layout->msg_count);
-    m->layout = ctx->layout->msgs[ctx->msg_count++];
-    UPB_ASSERT(m->field_count == m->layout->field_count);
-
-    // We don't need the result of this call, but it will assign layout_index
-    // for all the fields in O(n lg n) time.
-    _upb_FieldDefs_Sorted(m->fields, m->field_count, ctx->tmp_arena);
-  }
-
-  for (int i = 0; i < m->nested_msg_count; i++) {
-    upb_MessageDef* nested =
-        (upb_MessageDef*)upb_MessageDef_NestedMessage(m, i);
-    _upb_MessageDef_CreateMiniTable(ctx, nested);
-  }
-}
-
 void _upb_MessageDef_LinkMiniTable(upb_DefBuilder* ctx,
                                    const upb_MessageDef* m) {
-  for (int i = 0; i < upb_MessageDef_NestedExtensionCount(m); i++) {
-    const upb_FieldDef* ext = upb_MessageDef_NestedExtension(m, i);
-    _upb_FieldDef_BuildMiniTableExtension(ctx, ext);
-  }
-
-  for (int i = 0; i < m->nested_msg_count; i++) {
-    _upb_MessageDef_LinkMiniTable(ctx, upb_MessageDef_NestedMessage(m, i));
-  }
-
-  if (ctx->layout) return;
-
   for (int i = 0; i < m->field_count; i++) {
     const upb_FieldDef* f = upb_MessageDef_Field(m, i);
     const upb_MessageDef* sub_m = upb_FieldDef_MessageSubDef(f);
@@ -10717,17 +10631,9 @@
     }
   }
 
-#ifndef NDEBUG
-  for (int i = 0; i < m->field_count; i++) {
-    const upb_FieldDef* f = upb_MessageDef_Field(m, i);
-    const int layout_index = _upb_FieldDef_LayoutIndex(f);
-    UPB_ASSERT(layout_index < m->layout->field_count);
-    const upb_MiniTableField* mt_f = &m->layout->fields[layout_index];
-    UPB_ASSERT(upb_FieldDef_Type(f) == upb_MiniTableField_Type(mt_f));
-    UPB_ASSERT(upb_FieldDef_HasPresence(f) ==
-               upb_MiniTableField_HasPresence(mt_f));
+  for (int i = 0; i < m->nested_msg_count; i++) {
+    _upb_MessageDef_LinkMiniTable(ctx, upb_MessageDef_NestedMessage(m, i));
   }
-#endif
 }
 
 static uint64_t _upb_MessageDef_Modifiers(const upb_MessageDef* m) {
@@ -10860,6 +10766,7 @@
   m->is_sorted = true;
 
   name = UPB_DESC(DescriptorProto_name)(msg_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   m->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
   _upb_DefBuilder_Add(ctx, m->full_name, _upb_DefType_Pack(m, UPB_DEFTYPE_MSG));
@@ -10878,6 +10785,17 @@
   ok = upb_strtable_init(&m->ntof, n_oneof + n_field, ctx->arena);
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 
+  if (ctx->layout) {
+    /* create_fielddef() below depends on this being set. */
+    UPB_ASSERT(ctx->msg_count < ctx->layout->msg_count);
+    m->layout = ctx->layout->msgs[ctx->msg_count++];
+    UPB_ASSERT(n_field == m->layout->field_count);
+  } else {
+    /* Allocate now (to allow cross-linking), populate later. */
+    m->layout = _upb_DefBuilder_Alloc(
+        ctx, sizeof(*m->layout) + sizeof(_upb_FastTable_Entry));
+  }
+
   UPB_DEF_SET_OPTIONS(m->opts, DescriptorProto, MessageOptions, msg_proto);
 
   m->oneof_count = n_oneof;
@@ -10918,7 +10836,7 @@
   const UPB_DESC(FieldDescriptorProto)* const* exts =
       UPB_DESC(DescriptorProto_extension)(msg_proto, &n_ext);
   m->nested_ext_count = n_ext;
-  m->nested_exts = _upb_Extensions_New(ctx, n_ext, exts, m->full_name, m);
+  m->nested_exts = _upb_FieldDefs_New(ctx, n_ext, exts, m->full_name, m, NULL);
 
   const UPB_DESC(DescriptorProto)* const* msgs =
       UPB_DESC(DescriptorProto_nested_type)(msg_proto, &n_msg);
@@ -11325,6 +11243,7 @@
   s->file = _upb_DefBuilder_File(ctx);
 
   name = UPB_DESC(ServiceDescriptorProto_name)(svc_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
   const char* package = _upb_FileDef_RawPackage(s->file);
   s->full_name = _upb_DefBuilder_MakeFullName(ctx, package, name);
   _upb_DefBuilder_Add(ctx, s->full_name,
@@ -14092,15 +14011,6 @@
   encode_tag(e, kUpb_MsgSet_Item, kUpb_WireType_StartGroup);
 }
 
-static void encode_ext(upb_encstate* e, const upb_Message_Extension* ext,
-                       bool is_message_set) {
-  if (UPB_UNLIKELY(is_message_set)) {
-    encode_msgset_item(e, ext);
-  } else {
-    encode_field(e, &ext->data, &ext->ext->sub, &ext->ext->field);
-  }
-}
-
 static void encode_message(upb_encstate* e, const upb_Message* msg,
                            const upb_MiniTable* m, size_t* size) {
   size_t pre_len = e->limit - e->ptr;
@@ -14130,17 +14040,12 @@
     size_t ext_count;
     const upb_Message_Extension* ext = _upb_Message_Getexts(msg, &ext_count);
     if (ext_count) {
-      if (e->options & kUpb_EncodeOption_Deterministic) {
-        _upb_sortedmap sorted;
-        _upb_mapsorter_pushexts(&e->sorter, ext, ext_count, &sorted);
-        while (_upb_sortedmap_nextext(&e->sorter, &sorted, &ext)) {
-          encode_ext(e, ext, m->ext == kUpb_ExtMode_IsMessageSet);
-        }
-        _upb_mapsorter_popmap(&e->sorter, &sorted);
-      } else {
-        const upb_Message_Extension* end = ext + ext_count;
-        for (; ext != end; ext++) {
-          encode_ext(e, ext, m->ext == kUpb_ExtMode_IsMessageSet);
+      const upb_Message_Extension* end = ext + ext_count;
+      for (; ext != end; ext++) {
+        if (UPB_UNLIKELY(m->ext == kUpb_ExtMode_IsMessageSet)) {
+          encode_msgset_item(e, ext);
+        } else {
+          encode_field(e, &ext->data, &ext->ext->sub, &ext->ext->field);
         }
       }
     }
diff --git a/php/ext/google/protobuf/php-upb.h b/php/ext/google/protobuf/php-upb.h
index 3de3e6d..6b554cc 100644
--- a/php/ext/google/protobuf/php-upb.h
+++ b/php/ext/google/protobuf/php-upb.h
@@ -1422,6 +1422,179 @@
 #include <stdlib.h>
 
 
+#ifndef UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
+#define UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
+
+
+// Must be last.
+
+struct upb_Decoder;
+typedef const char* _upb_FieldParser(struct upb_Decoder* d, const char* ptr,
+                                     upb_Message* msg, intptr_t table,
+                                     uint64_t hasbits, uint64_t data);
+typedef struct {
+  uint64_t field_data;
+  _upb_FieldParser* field_parser;
+} _upb_FastTable_Entry;
+
+typedef enum {
+  kUpb_ExtMode_NonExtendable = 0,  // Non-extendable message.
+  kUpb_ExtMode_Extendable = 1,     // Normal extendable message.
+  kUpb_ExtMode_IsMessageSet = 2,   // MessageSet message.
+  kUpb_ExtMode_IsMessageSet_ITEM =
+      3,  // MessageSet item (temporary only, see decode.c)
+
+  // During table building we steal a bit to indicate that the message is a map
+  // entry.  *Only* used during table building!
+  kUpb_ExtMode_IsMapEntry = 4,
+} upb_ExtMode;
+
+// upb_MiniTable represents the memory layout of a given upb_MessageDef.
+// The members are public so generated code can initialize them,
+// but users MUST NOT directly read or write any of its members.
+struct upb_MiniTable {
+  const upb_MiniTableSub* subs;
+  const upb_MiniTableField* fields;
+
+  // Must be aligned to sizeof(void*). Doesn't include internal members like
+  // unknown fields, extension dict, pointer to msglayout, etc.
+  uint16_t size;
+
+  uint16_t field_count;
+  uint8_t ext;  // upb_ExtMode, declared as uint8_t so sizeof(ext) == 1
+  uint8_t dense_below;
+  uint8_t table_mask;
+  uint8_t required_count;  // Required fields have the lowest hasbits.
+
+  // To statically initialize the tables of variable length, we need a flexible
+  // array member, and we need to compile in gnu99 mode (constant initialization
+  // of flexible array members is a GNU extension, not in C99 unfortunately.
+  _upb_FastTable_Entry fasttable[];
+};
+
+// Map entries aren't actually stored for map fields, they are only used during
+// parsing. For parsing, it helps a lot if all map entry messages have the same
+// layout. The layout code in mini_table/decode.c will ensure that all map
+// entries have this layout.
+//
+// Note that users can and do create map entries directly, which will also use
+// this layout.
+//
+// NOTE: sync with mini_table/decode.c.
+typedef struct {
+  // We only need 2 hasbits max, but due to alignment we'll use 8 bytes here,
+  // and the uint64_t helps make this clear.
+  uint64_t hasbits;
+  union {
+    upb_StringView str;  // For str/bytes.
+    upb_value val;       // For all other types.
+  } k;
+  union {
+    upb_StringView str;  // For str/bytes.
+    upb_value val;       // For all other types.
+  } v;
+} upb_MapEntryData;
+
+typedef struct {
+  void* internal_data;
+  upb_MapEntryData data;
+} upb_MapEntry;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Computes a bitmask in which the |l->required_count| lowest bits are set,
+// except that we skip the lowest bit (because upb never uses hasbit 0).
+//
+// Sample output:
+//    requiredmask(1) => 0b10 (0x2)
+//    requiredmask(5) => 0b111110 (0x3e)
+UPB_INLINE uint64_t upb_MiniTable_requiredmask(const upb_MiniTable* l) {
+  int n = l->required_count;
+  assert(0 < n && n <= 63);
+  return ((1ULL << n) - 1) << 1;
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+
+#endif /* UPB_MINI_TABLE_MESSAGE_INTERNAL_H_ */
+
+// Must be last.
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// _upb_mapsorter sorts maps and provides ordered iteration over the entries.
+// Since maps can be recursive (map values can be messages which contain other
+// maps), _upb_mapsorter can contain a stack of maps.
+
+typedef struct {
+  upb_tabent const** entries;
+  int size;
+  int cap;
+} _upb_mapsorter;
+
+typedef struct {
+  int start;
+  int pos;
+  int end;
+} _upb_sortedmap;
+
+UPB_INLINE void _upb_mapsorter_init(_upb_mapsorter* s) {
+  s->entries = NULL;
+  s->size = 0;
+  s->cap = 0;
+}
+
+UPB_INLINE void _upb_mapsorter_destroy(_upb_mapsorter* s) {
+  if (s->entries) free(s->entries);
+}
+
+UPB_INLINE bool _upb_sortedmap_next(_upb_mapsorter* s, const upb_Map* map,
+                                    _upb_sortedmap* sorted, upb_MapEntry* ent) {
+  if (sorted->pos == sorted->end) return false;
+  const upb_tabent* tabent = s->entries[sorted->pos++];
+  upb_StringView key = upb_tabstrview(tabent->key);
+  _upb_map_fromkey(key, &ent->data.k, map->key_size);
+  upb_value val = {tabent->val.val};
+  _upb_map_fromvalue(val, &ent->data.v, map->val_size);
+  return true;
+}
+
+UPB_INLINE void _upb_mapsorter_popmap(_upb_mapsorter* s,
+                                      _upb_sortedmap* sorted) {
+  s->size = sorted->start;
+}
+
+bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
+                            const upb_Map* map, _upb_sortedmap* sorted);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+
+#endif /* UPB_COLLECTIONS_MAP_SORTER_INTERNAL_H_ */
+
+/*
+** Our memory representation for parsing tables and messages themselves.
+** Functions in this file are used by generated code and possibly reflection.
+**
+** The definitions in this file are internal to upb.
+**/
+
+#ifndef UPB_MESSAGE_INTERNAL_H_
+#define UPB_MESSAGE_INTERNAL_H_
+
+#include <stdlib.h>
+#include <string.h>
+
+
 #ifndef UPB_MESSAGE_EXTENSION_INTERNAL_H_
 #define UPB_MESSAGE_EXTENSION_INTERNAL_H_
 
@@ -1694,191 +1867,6 @@
 
 #endif /* UPB_MESSAGE_EXTENSION_INTERNAL_H_ */
 
-#ifndef UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
-#define UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
-
-
-// Must be last.
-
-struct upb_Decoder;
-typedef const char* _upb_FieldParser(struct upb_Decoder* d, const char* ptr,
-                                     upb_Message* msg, intptr_t table,
-                                     uint64_t hasbits, uint64_t data);
-typedef struct {
-  uint64_t field_data;
-  _upb_FieldParser* field_parser;
-} _upb_FastTable_Entry;
-
-typedef enum {
-  kUpb_ExtMode_NonExtendable = 0,  // Non-extendable message.
-  kUpb_ExtMode_Extendable = 1,     // Normal extendable message.
-  kUpb_ExtMode_IsMessageSet = 2,   // MessageSet message.
-  kUpb_ExtMode_IsMessageSet_ITEM =
-      3,  // MessageSet item (temporary only, see decode.c)
-
-  // During table building we steal a bit to indicate that the message is a map
-  // entry.  *Only* used during table building!
-  kUpb_ExtMode_IsMapEntry = 4,
-} upb_ExtMode;
-
-// upb_MiniTable represents the memory layout of a given upb_MessageDef.
-// The members are public so generated code can initialize them,
-// but users MUST NOT directly read or write any of its members.
-struct upb_MiniTable {
-  const upb_MiniTableSub* subs;
-  const upb_MiniTableField* fields;
-
-  // Must be aligned to sizeof(void*). Doesn't include internal members like
-  // unknown fields, extension dict, pointer to msglayout, etc.
-  uint16_t size;
-
-  uint16_t field_count;
-  uint8_t ext;  // upb_ExtMode, declared as uint8_t so sizeof(ext) == 1
-  uint8_t dense_below;
-  uint8_t table_mask;
-  uint8_t required_count;  // Required fields have the lowest hasbits.
-
-  // To statically initialize the tables of variable length, we need a flexible
-  // array member, and we need to compile in gnu99 mode (constant initialization
-  // of flexible array members is a GNU extension, not in C99 unfortunately.
-  _upb_FastTable_Entry fasttable[];
-};
-
-// Map entries aren't actually stored for map fields, they are only used during
-// parsing. For parsing, it helps a lot if all map entry messages have the same
-// layout. The layout code in mini_table/decode.c will ensure that all map
-// entries have this layout.
-//
-// Note that users can and do create map entries directly, which will also use
-// this layout.
-//
-// NOTE: sync with mini_table/decode.c.
-typedef struct {
-  // We only need 2 hasbits max, but due to alignment we'll use 8 bytes here,
-  // and the uint64_t helps make this clear.
-  uint64_t hasbits;
-  union {
-    upb_StringView str;  // For str/bytes.
-    upb_value val;       // For all other types.
-  } k;
-  union {
-    upb_StringView str;  // For str/bytes.
-    upb_value val;       // For all other types.
-  } v;
-} upb_MapEntryData;
-
-typedef struct {
-  void* internal_data;
-  upb_MapEntryData data;
-} upb_MapEntry;
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// Computes a bitmask in which the |l->required_count| lowest bits are set,
-// except that we skip the lowest bit (because upb never uses hasbit 0).
-//
-// Sample output:
-//    requiredmask(1) => 0b10 (0x2)
-//    requiredmask(5) => 0b111110 (0x3e)
-UPB_INLINE uint64_t upb_MiniTable_requiredmask(const upb_MiniTable* l) {
-  int n = l->required_count;
-  assert(0 < n && n <= 63);
-  return ((1ULL << n) - 1) << 1;
-}
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-
-#endif /* UPB_MINI_TABLE_MESSAGE_INTERNAL_H_ */
-
-// Must be last.
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// _upb_mapsorter sorts maps and provides ordered iteration over the entries.
-// Since maps can be recursive (map values can be messages which contain other
-// maps), _upb_mapsorter can contain a stack of maps.
-
-typedef struct {
-  void const** entries;
-  int size;
-  int cap;
-} _upb_mapsorter;
-
-typedef struct {
-  int start;
-  int pos;
-  int end;
-} _upb_sortedmap;
-
-UPB_INLINE void _upb_mapsorter_init(_upb_mapsorter* s) {
-  s->entries = NULL;
-  s->size = 0;
-  s->cap = 0;
-}
-
-UPB_INLINE void _upb_mapsorter_destroy(_upb_mapsorter* s) {
-  if (s->entries) free(s->entries);
-}
-
-UPB_INLINE bool _upb_sortedmap_next(_upb_mapsorter* s, const upb_Map* map,
-                                    _upb_sortedmap* sorted, upb_MapEntry* ent) {
-  if (sorted->pos == sorted->end) return false;
-  const upb_tabent* tabent = (const upb_tabent*)s->entries[sorted->pos++];
-  upb_StringView key = upb_tabstrview(tabent->key);
-  _upb_map_fromkey(key, &ent->data.k, map->key_size);
-  upb_value val = {tabent->val.val};
-  _upb_map_fromvalue(val, &ent->data.v, map->val_size);
-  return true;
-}
-
-UPB_INLINE bool _upb_sortedmap_nextext(_upb_mapsorter* s,
-                                       _upb_sortedmap* sorted,
-                                       const upb_Message_Extension** ext) {
-  if (sorted->pos == sorted->end) return false;
-  *ext = (const upb_Message_Extension*)s->entries[sorted->pos++];
-  return true;
-}
-
-UPB_INLINE void _upb_mapsorter_popmap(_upb_mapsorter* s,
-                                      _upb_sortedmap* sorted) {
-  s->size = sorted->start;
-}
-
-bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
-                            const upb_Map* map, _upb_sortedmap* sorted);
-
-bool _upb_mapsorter_pushexts(_upb_mapsorter* s,
-                             const upb_Message_Extension* exts, size_t count,
-                             _upb_sortedmap* sorted);
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-
-#endif /* UPB_COLLECTIONS_MAP_SORTER_INTERNAL_H_ */
-
-/*
-** Our memory representation for parsing tables and messages themselves.
-** Functions in this file are used by generated code and possibly reflection.
-**
-** The definitions in this file are internal to upb.
-**/
-
-#ifndef UPB_MESSAGE_INTERNAL_H_
-#define UPB_MESSAGE_INTERNAL_H_
-
-#include <stdlib.h>
-#include <string.h>
-
-
 #ifndef UPB_MINI_TABLE_EXTENSION_REGISTRY_H_
 #define UPB_MINI_TABLE_EXTENSION_REGISTRY_H_
 
@@ -8338,7 +8326,6 @@
 const char* upb_FileDef_Name(const upb_FileDef* f);
 const UPB_DESC(FileOptions) * upb_FileDef_Options(const upb_FileDef* f);
 const char* upb_FileDef_Package(const upb_FileDef* f);
-const char* upb_FileDef_Edition(const upb_FileDef* f);
 const upb_DefPool* upb_FileDef_Pool(const upb_FileDef* f);
 
 const upb_FileDef* upb_FileDef_PublicDependency(const upb_FileDef* f, int i);
@@ -8724,7 +8711,7 @@
 upb_ExtensionRegistry* _upb_DefPool_ExtReg(const upb_DefPool* s);
 
 bool _upb_DefPool_InsertExt(upb_DefPool* s, const upb_MiniTableExtension* ext,
-                            const upb_FieldDef* f);
+                            upb_FieldDef* f);
 bool _upb_DefPool_InsertSym(upb_DefPool* s, upb_StringView sym, upb_value v,
                             upb_Status* status);
 bool _upb_DefPool_LookupSym(const upb_DefPool* s, const char* sym, size_t size,
@@ -10210,6 +10197,23 @@
 void _upb_DefBuilder_CheckIdentSlow(upb_DefBuilder* ctx, upb_StringView name,
                                     bool full);
 
+// Verify a relative identifier string. The loop is branchless for speed.
+UPB_INLINE void _upb_DefBuilder_CheckIdentNotFull(upb_DefBuilder* ctx,
+                                                  upb_StringView name) {
+  bool good = name.size > 0;
+
+  for (size_t i = 0; i < name.size; i++) {
+    const char c = name.data[i];
+    const char d = c | 0x20;  // force lowercase
+    const bool is_alpha = (('a' <= d) & (d <= 'z')) | (c == '_');
+    const bool is_numer = ('0' <= c) & (c <= '9') & (i != 0);
+
+    good &= is_alpha | is_numer;
+  }
+
+  if (!good) _upb_DefBuilder_CheckIdentSlow(ctx, name, false);
+}
+
 // Verify a full identifier string. This is slightly more complicated than
 // verifying a relative identifier string because we must track '.' chars.
 UPB_INLINE void _upb_DefBuilder_CheckIdentFull(upb_DefBuilder* ctx,
@@ -10313,14 +10317,6 @@
 uint64_t _upb_FieldDef_Modifiers(const upb_FieldDef* f);
 void _upb_FieldDef_Resolve(upb_DefBuilder* ctx, const char* prefix,
                            upb_FieldDef* f);
-void _upb_FieldDef_BuildMiniTableExtension(upb_DefBuilder* ctx,
-                                           const upb_FieldDef* f);
-
-// Allocate and initialize an array of |n| extensions (field defs).
-upb_FieldDef* _upb_Extensions_New(
-    upb_DefBuilder* ctx, int n,
-    const UPB_DESC(FieldDescriptorProto) * const* protos, const char* prefix,
-    upb_MessageDef* m);
 
 // Allocate and initialize an array of |n| field defs.
 upb_FieldDef* _upb_FieldDefs_New(
@@ -10385,7 +10381,6 @@
 void _upb_MessageDef_InsertField(upb_DefBuilder* ctx, upb_MessageDef* m,
                                  const upb_FieldDef* f);
 bool _upb_MessageDef_IsValidExtensionNumber(const upb_MessageDef* m, int n);
-void _upb_MessageDef_CreateMiniTable(upb_DefBuilder* ctx, upb_MessageDef* m);
 void _upb_MessageDef_LinkMiniTable(upb_DefBuilder* ctx,
                                    const upb_MessageDef* m);
 void _upb_MessageDef_Resolve(upb_DefBuilder* ctx, upb_MessageDef* m);
diff --git a/protobuf_deps.bzl b/protobuf_deps.bzl
index 9f6436e..fee1e9c 100644
--- a/protobuf_deps.bzl
+++ b/protobuf_deps.bzl
@@ -149,7 +149,7 @@
         _github_archive(
             name = "upb",
             repo = "https://github.com/protocolbuffers/upb",
-            commit = "1fb480bc76bc0e331564d672e60b97a388aa3f76",
-            sha256 = "a5396af1eeb1144c17cec454332997374d32854007f74390b154ec7255b49ded",
+            commit = "662497f1d3dcced2bba1620cea9aae8b484bd3cd",
+            sha256 = "57c87ca4145d2cbc162a6c613b114b9325b577f4f6525bd78747a34b3d03627c",
             patches = ["@com_google_protobuf//build_defs:upb.patch"],
         )
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index bda70b2..6fbf78b 100644
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -641,12 +641,14 @@
     [kUpb_FieldType_Bytes] = _upb_mapsorter_cmpstr,
 };
 
-static bool _upb_mapsorter_resize(_upb_mapsorter* s, _upb_sortedmap* sorted,
-                                  int size) {
+bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
+                            const upb_Map* map, _upb_sortedmap* sorted) {
+  int map_size = _upb_Map_Size(map);
   sorted->start = s->size;
   sorted->pos = sorted->start;
-  sorted->end = sorted->start + size;
+  sorted->end = sorted->start + map_size;
 
+  // Grow s->entries if necessary.
   if (sorted->end > s->cap) {
     s->cap = upb_Log2CeilingSize(sorted->end);
     s->entries = realloc(s->entries, s->cap * sizeof(*s->entries));
@@ -654,17 +656,9 @@
   }
 
   s->size = sorted->end;
-  return true;
-}
-
-bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
-                            const upb_Map* map, _upb_sortedmap* sorted) {
-  int map_size = _upb_Map_Size(map);
-
-  if (!_upb_mapsorter_resize(s, sorted, map_size)) return false;
 
   // Copy non-empty entries from the table to s->entries.
-  const void** dst = &s->entries[sorted->start];
+  upb_tabent const** dst = &s->entries[sorted->start];
   const upb_tabent* src = map->table.t.entries;
   const upb_tabent* end = src + upb_table_size(&map->table.t);
   for (; src < end; src++) {
@@ -680,29 +674,6 @@
         compar[key_type]);
   return true;
 }
-
-static int _upb_mapsorter_cmpext(const void* _a, const void* _b) {
-  const upb_Message_Extension* const* a = _a;
-  const upb_Message_Extension* const* b = _b;
-  uint32_t a_num = (*a)->ext->field.number;
-  uint32_t b_num = (*b)->ext->field.number;
-  assert(a_num != b_num);
-  return a_num < b_num ? -1 : 1;
-}
-
-bool _upb_mapsorter_pushexts(_upb_mapsorter* s,
-                             const upb_Message_Extension* exts, size_t count,
-                             _upb_sortedmap* sorted) {
-  if (!_upb_mapsorter_resize(s, sorted, count)) return false;
-
-  for (size_t i = 0; i < count; i++) {
-    s->entries[sorted->start + i] = &exts[i];
-  }
-
-  qsort(&s->entries[sorted->start], count, sizeof(*s->entries),
-        _upb_mapsorter_cmpext);
-  return true;
-}
 /* This file was generated by upbc (the upb compiler) from the input
  * file:
  *
@@ -1891,7 +1862,7 @@
   n = len + 1;
   p = upb_Arena_Malloc(a, n);
   if (p) {
-    if (len != 0) memcpy(p, s, len);
+    memcpy(p, s, len);
     p[len] = 0;
   }
   return p;
@@ -7227,27 +7198,9 @@
   _upb_DefBuilder_FailJmp(ctx);
 }
 
-// Verify a relative identifier string. The loop is branchless for speed.
-static void _upb_DefBuilder_CheckIdentNotFull(upb_DefBuilder* ctx,
-                                              upb_StringView name) {
-  bool good = name.size > 0;
-
-  for (size_t i = 0; i < name.size; i++) {
-    const char c = name.data[i];
-    const char d = c | 0x20;  // force lowercase
-    const bool is_alpha = (('a' <= d) & (d <= 'z')) | (c == '_');
-    const bool is_numer = ('0' <= c) & (c <= '9') & (i != 0);
-
-    good &= is_alpha | is_numer;
-  }
-
-  if (!good) _upb_DefBuilder_CheckIdentSlow(ctx, name, false);
-}
-
 const char* _upb_DefBuilder_MakeFullName(upb_DefBuilder* ctx,
                                          const char* prefix,
                                          upb_StringView name) {
-  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
   if (prefix) {
     // ret = prefix + '.' + name;
     size_t n = strlen(prefix);
@@ -7363,7 +7316,7 @@
   return true;
 }
 
-static int TryGetHexDigit(const char** src, const char* end) {
+static char TryGetHexDigit(const char** src, const char* end) {
   char ch;
   if (!TryGetChar(src, end, &ch)) return -1;
   if ('0' <= ch && ch <= '9') {
@@ -7380,10 +7333,10 @@
 static char upb_DefBuilder_ParseHexEscape(upb_DefBuilder* ctx,
                                           const upb_FieldDef* f,
                                           const char** src, const char* end) {
-  int hex_digit = TryGetHexDigit(src, end);
+  char hex_digit = TryGetHexDigit(src, end);
   if (hex_digit < 0) {
     _upb_DefBuilder_Errf(
-        ctx, "\\x must be followed by at least one hex digit (field='%s')",
+        ctx, "\\x cannot be followed by non-hex digit in field '%s' default",
         upb_FieldDef_FullName(f));
     return 0;
   }
@@ -7559,7 +7512,7 @@
 }
 
 bool _upb_DefPool_InsertExt(upb_DefPool* s, const upb_MiniTableExtension* ext,
-                            const upb_FieldDef* f) {
+                            upb_FieldDef* f) {
   return upb_inttable_insert(&s->exts, (uintptr_t)ext, upb_value_constptr(f),
                              s->arena);
 }
@@ -7791,6 +7744,12 @@
     const upb_MiniTableFile* layout, upb_Status* status) {
   const upb_StringView name = UPB_DESC(FileDescriptorProto_name)(file_proto);
 
+  if (name.size == 0) {
+    upb_Status_SetErrorFormat(status,
+                              "missing name in google_protobuf_FileDescriptorProto");
+    return NULL;
+  }
+
   // Determine whether we already know about this file.
   {
     upb_value v;
@@ -8182,6 +8141,7 @@
   e->file = _upb_DefBuilder_File(ctx);
 
   name = UPB_DESC(EnumDescriptorProto_name)(enum_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   e->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
   _upb_DefBuilder_Add(ctx, e->full_name,
@@ -8991,14 +8951,7 @@
   }
 
   const upb_StringView name = UPB_DESC(FieldDescriptorProto_name)(field_proto);
-
-  f->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
-  f->label_ = (int)UPB_DESC(FieldDescriptorProto_label)(field_proto);
-  f->number_ = UPB_DESC(FieldDescriptorProto_number)(field_proto);
-  f->is_proto3_optional =
-      UPB_DESC(FieldDescriptorProto_proto3_optional)(field_proto);
-  f->msgdef = m;
-  f->scope.oneof = NULL;
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   f->has_json_name = UPB_DESC(FieldDescriptorProto_has_json_name)(field_proto);
   if (f->has_json_name) {
@@ -9010,6 +8963,14 @@
   }
   if (!f->json_name) _upb_DefBuilder_OomErr(ctx);
 
+  f->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
+  f->label_ = (int)UPB_DESC(FieldDescriptorProto_label)(field_proto);
+  f->number_ = UPB_DESC(FieldDescriptorProto_number)(field_proto);
+  f->is_proto3_optional =
+      UPB_DESC(FieldDescriptorProto_proto3_optional)(field_proto);
+  f->msgdef = m;
+  f->scope.oneof = NULL;
+
   const bool has_type = UPB_DESC(FieldDescriptorProto_has_type)(field_proto);
   const bool has_type_name =
       UPB_DESC(FieldDescriptorProto_has_type_name)(field_proto);
@@ -9139,24 +9100,19 @@
   }
 
   _upb_MessageDef_InsertField(ctx, m, f);
-}
 
-upb_FieldDef* _upb_Extensions_New(
-    upb_DefBuilder* ctx, int n,
-    const UPB_DESC(FieldDescriptorProto) * const* protos, const char* prefix,
-    upb_MessageDef* m) {
-  _upb_DefType_CheckPadding(sizeof(upb_FieldDef));
-  upb_FieldDef* defs =
-      (upb_FieldDef*)_upb_DefBuilder_Alloc(ctx, sizeof(upb_FieldDef) * n);
+  if (!ctx->layout) return;
 
-  for (int i = 0; i < n; i++) {
-    upb_FieldDef* f = &defs[i];
-
-    _upb_FieldDef_CreateExt(ctx, prefix, protos[i], m, f);
-    f->index_ = i;
+  const upb_MiniTable* mt = upb_MessageDef_MiniTable(m);
+  const upb_MiniTableField* fields = mt->fields;
+  for (int i = 0; i < mt->field_count; i++) {
+    if (fields[i].number == f->number_) {
+      f->layout_index = i;
+      return;
+    }
   }
 
-  return defs;
+  UPB_ASSERT(false);  // It should be impossible to reach this point.
 }
 
 upb_FieldDef* _upb_FieldDefs_New(
@@ -9167,23 +9123,28 @@
   upb_FieldDef* defs =
       (upb_FieldDef*)_upb_DefBuilder_Alloc(ctx, sizeof(upb_FieldDef) * n);
 
-  uint32_t previous = 0;
-  for (int i = 0; i < n; i++) {
-    upb_FieldDef* f = &defs[i];
+  // If we are creating extensions then is_sorted will be NULL.
+  // If we are not creating extensions then is_sorted will be non-NULL.
+  if (is_sorted) {
+    uint32_t previous = 0;
+    for (int i = 0; i < n; i++) {
+      upb_FieldDef* f = &defs[i];
 
-    _upb_FieldDef_CreateNotExt(ctx, prefix, protos[i], m, f);
-    f->index_ = i;
-    if (!ctx->layout) {
-      // Speculate that the def fields are sorted.  We will always sort the
-      // MiniTable fields, so if defs are sorted then indices will match.
-      //
-      // If this is incorrect, we will overwrite later.
-      f->layout_index = i;
+      _upb_FieldDef_CreateNotExt(ctx, prefix, protos[i], m, f);
+      f->index_ = i;
+      if (!ctx->layout) f->layout_index = i;
+
+      const uint32_t current = f->number_;
+      if (previous > current) *is_sorted = false;
+      previous = current;
     }
+  } else {
+    for (int i = 0; i < n; i++) {
+      upb_FieldDef* f = &defs[i];
 
-    const uint32_t current = f->number_;
-    if (previous > current) *is_sorted = false;
-    previous = current;
+      _upb_FieldDef_CreateExt(ctx, prefix, protos[i], m, f);
+      f->index_ = i;
+    }
   }
 
   return defs;
@@ -9239,9 +9200,6 @@
   return (v1 < v2) ? -1 : (v1 > v2);
 }
 
-// _upb_FieldDefs_Sorted() is mostly a pure function of its inputs, but has one
-// critical side effect that we depend on: it sets layout_index appropriately
-// for non-sorted lists of fields.
 const upb_FieldDef** _upb_FieldDefs_Sorted(const upb_FieldDef* f, int n,
                                            upb_Arena* a) {
   // TODO(salo): Replace this arena alloc with a persistent scratch buffer.
@@ -9299,10 +9257,7 @@
         "field number %u in extension %s has no extension range in message %s",
         (unsigned)f->number_, f->full_name, upb_MessageDef_FullName(m));
   }
-}
 
-void _upb_FieldDef_BuildMiniTableExtension(upb_DefBuilder* ctx,
-                                           const upb_FieldDef* f) {
   const upb_MiniTableExtension* ext = _upb_FieldDef_ExtensionMiniTable(f);
 
   if (ctx->layout) {
@@ -9321,8 +9276,8 @@
       sub.subenum = _upb_EnumDef_MiniTable(f->sub.enumdef);
     }
     bool ok2 = upb_MiniTableExtension_Build(desc.data, desc.size, mut_ext,
-                                            upb_MessageDef_MiniTable(f->msgdef),
-                                            sub, ctx->status);
+                                            upb_MessageDef_MiniTable(m), sub,
+                                            ctx->status);
     if (!ok2) _upb_DefBuilder_Errf(ctx, "Could not build extension mini table");
   }
 
@@ -9379,7 +9334,6 @@
   const UPB_DESC(FileOptions) * opts;
   const char* name;
   const char* package;
-  const char* edition;
 
   const upb_FileDef** deps;
   const int32_t* public_deps;
@@ -9416,10 +9370,6 @@
   return f->package ? f->package : "";
 }
 
-const char* upb_FileDef_Edition(const upb_FileDef* f) {
-  return f->edition ? f->edition : "";
-}
-
 const char* _upb_FileDef_RawPackage(const upb_FileDef* f) { return f->package; }
 
 upb_Syntax upb_FileDef_Syntax(const upb_FileDef* f) { return f->syntax; }
@@ -9567,14 +9517,13 @@
     }
   }
 
-  upb_StringView name = UPB_DESC(FileDescriptorProto_name)(file_proto);
-  file->name = strviewdup(ctx, name);
-  if (strlen(file->name) != name.size) {
-    _upb_DefBuilder_Errf(ctx, "File name contained embedded NULL");
+  if (!UPB_DESC(FileDescriptorProto_has_name)(file_proto)) {
+    _upb_DefBuilder_Errf(ctx, "File has no name");
   }
 
-  upb_StringView package = UPB_DESC(FileDescriptorProto_package)(file_proto);
+  file->name = strviewdup(ctx, UPB_DESC(FileDescriptorProto_name)(file_proto));
 
+  upb_StringView package = UPB_DESC(FileDescriptorProto_package)(file_proto);
   if (package.size) {
     _upb_DefBuilder_CheckIdentFull(ctx, package);
     file->package = strviewdup(ctx, package);
@@ -9582,18 +9531,6 @@
     file->package = NULL;
   }
 
-  upb_StringView edition = UPB_DESC(FileDescriptorProto_edition)(file_proto);
-
-  if (edition.size == 0) {
-    file->edition = NULL;
-  } else {
-    // TODO(b/267770604): How should we validate this?
-    file->edition = strviewdup(ctx, edition);
-    if (strlen(file->edition) != edition.size) {
-      _upb_DefBuilder_Errf(ctx, "Edition name contained embedded NULL");
-    }
-  }
-
   if (UPB_DESC(FileDescriptorProto_has_syntax)(file_proto)) {
     upb_StringView syntax = UPB_DESC(FileDescriptorProto_syntax)(file_proto);
 
@@ -9662,7 +9599,8 @@
   // Create extensions.
   exts = UPB_DESC(FileDescriptorProto_extension)(file_proto, &n);
   file->top_lvl_ext_count = n;
-  file->top_lvl_exts = _upb_Extensions_New(ctx, n, exts, file->package, NULL);
+  file->top_lvl_exts =
+      _upb_FieldDefs_New(ctx, n, exts, file->package, NULL, NULL);
 
   // Create messages.
   msgs = UPB_DESC(FileDescriptorProto_message_type)(file_proto, &n);
@@ -9686,19 +9624,11 @@
     _upb_FieldDef_Resolve(ctx, file->package, f);
   }
 
-  for (int i = 0; i < file->top_lvl_msg_count; i++) {
-    upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
-    _upb_MessageDef_CreateMiniTable(ctx, (upb_MessageDef*)m);
-  }
-
-  for (int i = 0; i < file->top_lvl_ext_count; i++) {
-    upb_FieldDef* f = (upb_FieldDef*)upb_FileDef_TopLevelExtension(file, i);
-    _upb_FieldDef_BuildMiniTableExtension(ctx, f);
-  }
-
-  for (int i = 0; i < file->top_lvl_msg_count; i++) {
-    upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
-    _upb_MessageDef_LinkMiniTable(ctx, m);
+  if (!ctx->layout) {
+    for (int i = 0; i < file->top_lvl_msg_count; i++) {
+      upb_MessageDef* m = (upb_MessageDef*)upb_FileDef_TopLevelMessage(file, i);
+      _upb_MessageDef_LinkMiniTable(ctx, m);
+    }
   }
 
   if (file->ext_count) {
@@ -10211,8 +10141,6 @@
 static upb_MiniTable* _upb_MessageDef_MakeMiniTable(upb_DefBuilder* ctx,
                                                     const upb_MessageDef* m) {
   upb_StringView desc;
-  // Note: this will assign layout_index for fields, so upb_FieldDef_MiniTable()
-  // is safe to call only after this call.
   bool ok = upb_MessageDef_MiniDescriptorEncode(m, ctx->tmp_arena, &desc);
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 
@@ -10232,6 +10160,23 @@
     _upb_FieldDef_Resolve(ctx, m->full_name, f);
   }
 
+  if (!ctx->layout) {
+    m->layout = _upb_MessageDef_MakeMiniTable(ctx, m);
+    if (!m->layout) _upb_DefBuilder_OomErr(ctx);
+  }
+
+#ifndef NDEBUG
+  for (int i = 0; i < m->field_count; i++) {
+    const upb_FieldDef* f = upb_MessageDef_Field(m, i);
+    const int layout_index = _upb_FieldDef_LayoutIndex(f);
+    UPB_ASSERT(layout_index < m->layout->field_count);
+    const upb_MiniTableField* mt_f = &m->layout->fields[layout_index];
+    UPB_ASSERT(upb_FieldDef_Type(f) == upb_MiniTableField_Type(mt_f));
+    UPB_ASSERT(upb_FieldDef_HasPresence(f) ==
+               upb_MiniTableField_HasPresence(mt_f));
+  }
+#endif
+
   m->in_message_set = false;
   for (int i = 0; i < upb_MessageDef_NestedExtensionCount(m); i++) {
     upb_FieldDef* ext = (upb_FieldDef*)upb_MessageDef_NestedExtension(m, i);
@@ -10294,39 +10239,8 @@
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 }
 
-void _upb_MessageDef_CreateMiniTable(upb_DefBuilder* ctx, upb_MessageDef* m) {
-  if (ctx->layout == NULL) {
-    m->layout = _upb_MessageDef_MakeMiniTable(ctx, m);
-  } else {
-    UPB_ASSERT(ctx->msg_count < ctx->layout->msg_count);
-    m->layout = ctx->layout->msgs[ctx->msg_count++];
-    UPB_ASSERT(m->field_count == m->layout->field_count);
-
-    // We don't need the result of this call, but it will assign layout_index
-    // for all the fields in O(n lg n) time.
-    _upb_FieldDefs_Sorted(m->fields, m->field_count, ctx->tmp_arena);
-  }
-
-  for (int i = 0; i < m->nested_msg_count; i++) {
-    upb_MessageDef* nested =
-        (upb_MessageDef*)upb_MessageDef_NestedMessage(m, i);
-    _upb_MessageDef_CreateMiniTable(ctx, nested);
-  }
-}
-
 void _upb_MessageDef_LinkMiniTable(upb_DefBuilder* ctx,
                                    const upb_MessageDef* m) {
-  for (int i = 0; i < upb_MessageDef_NestedExtensionCount(m); i++) {
-    const upb_FieldDef* ext = upb_MessageDef_NestedExtension(m, i);
-    _upb_FieldDef_BuildMiniTableExtension(ctx, ext);
-  }
-
-  for (int i = 0; i < m->nested_msg_count; i++) {
-    _upb_MessageDef_LinkMiniTable(ctx, upb_MessageDef_NestedMessage(m, i));
-  }
-
-  if (ctx->layout) return;
-
   for (int i = 0; i < m->field_count; i++) {
     const upb_FieldDef* f = upb_MessageDef_Field(m, i);
     const upb_MessageDef* sub_m = upb_FieldDef_MessageSubDef(f);
@@ -10354,17 +10268,9 @@
     }
   }
 
-#ifndef NDEBUG
-  for (int i = 0; i < m->field_count; i++) {
-    const upb_FieldDef* f = upb_MessageDef_Field(m, i);
-    const int layout_index = _upb_FieldDef_LayoutIndex(f);
-    UPB_ASSERT(layout_index < m->layout->field_count);
-    const upb_MiniTableField* mt_f = &m->layout->fields[layout_index];
-    UPB_ASSERT(upb_FieldDef_Type(f) == upb_MiniTableField_Type(mt_f));
-    UPB_ASSERT(upb_FieldDef_HasPresence(f) ==
-               upb_MiniTableField_HasPresence(mt_f));
+  for (int i = 0; i < m->nested_msg_count; i++) {
+    _upb_MessageDef_LinkMiniTable(ctx, upb_MessageDef_NestedMessage(m, i));
   }
-#endif
 }
 
 static uint64_t _upb_MessageDef_Modifiers(const upb_MessageDef* m) {
@@ -10497,6 +10403,7 @@
   m->is_sorted = true;
 
   name = UPB_DESC(DescriptorProto_name)(msg_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
 
   m->full_name = _upb_DefBuilder_MakeFullName(ctx, prefix, name);
   _upb_DefBuilder_Add(ctx, m->full_name, _upb_DefType_Pack(m, UPB_DEFTYPE_MSG));
@@ -10515,6 +10422,17 @@
   ok = upb_strtable_init(&m->ntof, n_oneof + n_field, ctx->arena);
   if (!ok) _upb_DefBuilder_OomErr(ctx);
 
+  if (ctx->layout) {
+    /* create_fielddef() below depends on this being set. */
+    UPB_ASSERT(ctx->msg_count < ctx->layout->msg_count);
+    m->layout = ctx->layout->msgs[ctx->msg_count++];
+    UPB_ASSERT(n_field == m->layout->field_count);
+  } else {
+    /* Allocate now (to allow cross-linking), populate later. */
+    m->layout = _upb_DefBuilder_Alloc(
+        ctx, sizeof(*m->layout) + sizeof(_upb_FastTable_Entry));
+  }
+
   UPB_DEF_SET_OPTIONS(m->opts, DescriptorProto, MessageOptions, msg_proto);
 
   m->oneof_count = n_oneof;
@@ -10555,7 +10473,7 @@
   const UPB_DESC(FieldDescriptorProto)* const* exts =
       UPB_DESC(DescriptorProto_extension)(msg_proto, &n_ext);
   m->nested_ext_count = n_ext;
-  m->nested_exts = _upb_Extensions_New(ctx, n_ext, exts, m->full_name, m);
+  m->nested_exts = _upb_FieldDefs_New(ctx, n_ext, exts, m->full_name, m, NULL);
 
   const UPB_DESC(DescriptorProto)* const* msgs =
       UPB_DESC(DescriptorProto_nested_type)(msg_proto, &n_msg);
@@ -10962,6 +10880,7 @@
   s->file = _upb_DefBuilder_File(ctx);
 
   name = UPB_DESC(ServiceDescriptorProto_name)(svc_proto);
+  _upb_DefBuilder_CheckIdentNotFull(ctx, name);
   const char* package = _upb_FileDef_RawPackage(s->file);
   s->full_name = _upb_DefBuilder_MakeFullName(ctx, package, name);
   _upb_DefBuilder_Add(ctx, s->full_name,
@@ -13729,15 +13648,6 @@
   encode_tag(e, kUpb_MsgSet_Item, kUpb_WireType_StartGroup);
 }
 
-static void encode_ext(upb_encstate* e, const upb_Message_Extension* ext,
-                       bool is_message_set) {
-  if (UPB_UNLIKELY(is_message_set)) {
-    encode_msgset_item(e, ext);
-  } else {
-    encode_field(e, &ext->data, &ext->ext->sub, &ext->ext->field);
-  }
-}
-
 static void encode_message(upb_encstate* e, const upb_Message* msg,
                            const upb_MiniTable* m, size_t* size) {
   size_t pre_len = e->limit - e->ptr;
@@ -13767,17 +13677,12 @@
     size_t ext_count;
     const upb_Message_Extension* ext = _upb_Message_Getexts(msg, &ext_count);
     if (ext_count) {
-      if (e->options & kUpb_EncodeOption_Deterministic) {
-        _upb_sortedmap sorted;
-        _upb_mapsorter_pushexts(&e->sorter, ext, ext_count, &sorted);
-        while (_upb_sortedmap_nextext(&e->sorter, &sorted, &ext)) {
-          encode_ext(e, ext, m->ext == kUpb_ExtMode_IsMessageSet);
-        }
-        _upb_mapsorter_popmap(&e->sorter, &sorted);
-      } else {
-        const upb_Message_Extension* end = ext + ext_count;
-        for (; ext != end; ext++) {
-          encode_ext(e, ext, m->ext == kUpb_ExtMode_IsMessageSet);
+      const upb_Message_Extension* end = ext + ext_count;
+      for (; ext != end; ext++) {
+        if (UPB_UNLIKELY(m->ext == kUpb_ExtMode_IsMessageSet)) {
+          encode_msgset_item(e, ext);
+        } else {
+          encode_field(e, &ext->data, &ext->ext->sub, &ext->ext->field);
         }
       }
     }
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.h b/ruby/ext/google/protobuf_c/ruby-upb.h
index 0af88d6..cd703c2 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.h
+++ b/ruby/ext/google/protobuf_c/ruby-upb.h
@@ -1424,6 +1424,179 @@
 #include <stdlib.h>
 
 
+#ifndef UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
+#define UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
+
+
+// Must be last.
+
+struct upb_Decoder;
+typedef const char* _upb_FieldParser(struct upb_Decoder* d, const char* ptr,
+                                     upb_Message* msg, intptr_t table,
+                                     uint64_t hasbits, uint64_t data);
+typedef struct {
+  uint64_t field_data;
+  _upb_FieldParser* field_parser;
+} _upb_FastTable_Entry;
+
+typedef enum {
+  kUpb_ExtMode_NonExtendable = 0,  // Non-extendable message.
+  kUpb_ExtMode_Extendable = 1,     // Normal extendable message.
+  kUpb_ExtMode_IsMessageSet = 2,   // MessageSet message.
+  kUpb_ExtMode_IsMessageSet_ITEM =
+      3,  // MessageSet item (temporary only, see decode.c)
+
+  // During table building we steal a bit to indicate that the message is a map
+  // entry.  *Only* used during table building!
+  kUpb_ExtMode_IsMapEntry = 4,
+} upb_ExtMode;
+
+// upb_MiniTable represents the memory layout of a given upb_MessageDef.
+// The members are public so generated code can initialize them,
+// but users MUST NOT directly read or write any of its members.
+struct upb_MiniTable {
+  const upb_MiniTableSub* subs;
+  const upb_MiniTableField* fields;
+
+  // Must be aligned to sizeof(void*). Doesn't include internal members like
+  // unknown fields, extension dict, pointer to msglayout, etc.
+  uint16_t size;
+
+  uint16_t field_count;
+  uint8_t ext;  // upb_ExtMode, declared as uint8_t so sizeof(ext) == 1
+  uint8_t dense_below;
+  uint8_t table_mask;
+  uint8_t required_count;  // Required fields have the lowest hasbits.
+
+  // To statically initialize the tables of variable length, we need a flexible
+  // array member, and we need to compile in gnu99 mode (constant initialization
+  // of flexible array members is a GNU extension, not in C99 unfortunately.
+  _upb_FastTable_Entry fasttable[];
+};
+
+// Map entries aren't actually stored for map fields, they are only used during
+// parsing. For parsing, it helps a lot if all map entry messages have the same
+// layout. The layout code in mini_table/decode.c will ensure that all map
+// entries have this layout.
+//
+// Note that users can and do create map entries directly, which will also use
+// this layout.
+//
+// NOTE: sync with mini_table/decode.c.
+typedef struct {
+  // We only need 2 hasbits max, but due to alignment we'll use 8 bytes here,
+  // and the uint64_t helps make this clear.
+  uint64_t hasbits;
+  union {
+    upb_StringView str;  // For str/bytes.
+    upb_value val;       // For all other types.
+  } k;
+  union {
+    upb_StringView str;  // For str/bytes.
+    upb_value val;       // For all other types.
+  } v;
+} upb_MapEntryData;
+
+typedef struct {
+  void* internal_data;
+  upb_MapEntryData data;
+} upb_MapEntry;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Computes a bitmask in which the |l->required_count| lowest bits are set,
+// except that we skip the lowest bit (because upb never uses hasbit 0).
+//
+// Sample output:
+//    requiredmask(1) => 0b10 (0x2)
+//    requiredmask(5) => 0b111110 (0x3e)
+UPB_INLINE uint64_t upb_MiniTable_requiredmask(const upb_MiniTable* l) {
+  int n = l->required_count;
+  assert(0 < n && n <= 63);
+  return ((1ULL << n) - 1) << 1;
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+
+#endif /* UPB_MINI_TABLE_MESSAGE_INTERNAL_H_ */
+
+// Must be last.
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// _upb_mapsorter sorts maps and provides ordered iteration over the entries.
+// Since maps can be recursive (map values can be messages which contain other
+// maps), _upb_mapsorter can contain a stack of maps.
+
+typedef struct {
+  upb_tabent const** entries;
+  int size;
+  int cap;
+} _upb_mapsorter;
+
+typedef struct {
+  int start;
+  int pos;
+  int end;
+} _upb_sortedmap;
+
+UPB_INLINE void _upb_mapsorter_init(_upb_mapsorter* s) {
+  s->entries = NULL;
+  s->size = 0;
+  s->cap = 0;
+}
+
+UPB_INLINE void _upb_mapsorter_destroy(_upb_mapsorter* s) {
+  if (s->entries) free(s->entries);
+}
+
+UPB_INLINE bool _upb_sortedmap_next(_upb_mapsorter* s, const upb_Map* map,
+                                    _upb_sortedmap* sorted, upb_MapEntry* ent) {
+  if (sorted->pos == sorted->end) return false;
+  const upb_tabent* tabent = s->entries[sorted->pos++];
+  upb_StringView key = upb_tabstrview(tabent->key);
+  _upb_map_fromkey(key, &ent->data.k, map->key_size);
+  upb_value val = {tabent->val.val};
+  _upb_map_fromvalue(val, &ent->data.v, map->val_size);
+  return true;
+}
+
+UPB_INLINE void _upb_mapsorter_popmap(_upb_mapsorter* s,
+                                      _upb_sortedmap* sorted) {
+  s->size = sorted->start;
+}
+
+bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
+                            const upb_Map* map, _upb_sortedmap* sorted);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+
+#endif /* UPB_COLLECTIONS_MAP_SORTER_INTERNAL_H_ */
+
+/*
+** Our memory representation for parsing tables and messages themselves.
+** Functions in this file are used by generated code and possibly reflection.
+**
+** The definitions in this file are internal to upb.
+**/
+
+#ifndef UPB_MESSAGE_INTERNAL_H_
+#define UPB_MESSAGE_INTERNAL_H_
+
+#include <stdlib.h>
+#include <string.h>
+
+
 #ifndef UPB_MESSAGE_EXTENSION_INTERNAL_H_
 #define UPB_MESSAGE_EXTENSION_INTERNAL_H_
 
@@ -1696,191 +1869,6 @@
 
 #endif /* UPB_MESSAGE_EXTENSION_INTERNAL_H_ */
 
-#ifndef UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
-#define UPB_MINI_TABLE_MESSAGE_INTERNAL_H_
-
-
-// Must be last.
-
-struct upb_Decoder;
-typedef const char* _upb_FieldParser(struct upb_Decoder* d, const char* ptr,
-                                     upb_Message* msg, intptr_t table,
-                                     uint64_t hasbits, uint64_t data);
-typedef struct {
-  uint64_t field_data;
-  _upb_FieldParser* field_parser;
-} _upb_FastTable_Entry;
-
-typedef enum {
-  kUpb_ExtMode_NonExtendable = 0,  // Non-extendable message.
-  kUpb_ExtMode_Extendable = 1,     // Normal extendable message.
-  kUpb_ExtMode_IsMessageSet = 2,   // MessageSet message.
-  kUpb_ExtMode_IsMessageSet_ITEM =
-      3,  // MessageSet item (temporary only, see decode.c)
-
-  // During table building we steal a bit to indicate that the message is a map
-  // entry.  *Only* used during table building!
-  kUpb_ExtMode_IsMapEntry = 4,
-} upb_ExtMode;
-
-// upb_MiniTable represents the memory layout of a given upb_MessageDef.
-// The members are public so generated code can initialize them,
-// but users MUST NOT directly read or write any of its members.
-struct upb_MiniTable {
-  const upb_MiniTableSub* subs;
-  const upb_MiniTableField* fields;
-
-  // Must be aligned to sizeof(void*). Doesn't include internal members like
-  // unknown fields, extension dict, pointer to msglayout, etc.
-  uint16_t size;
-
-  uint16_t field_count;
-  uint8_t ext;  // upb_ExtMode, declared as uint8_t so sizeof(ext) == 1
-  uint8_t dense_below;
-  uint8_t table_mask;
-  uint8_t required_count;  // Required fields have the lowest hasbits.
-
-  // To statically initialize the tables of variable length, we need a flexible
-  // array member, and we need to compile in gnu99 mode (constant initialization
-  // of flexible array members is a GNU extension, not in C99 unfortunately.
-  _upb_FastTable_Entry fasttable[];
-};
-
-// Map entries aren't actually stored for map fields, they are only used during
-// parsing. For parsing, it helps a lot if all map entry messages have the same
-// layout. The layout code in mini_table/decode.c will ensure that all map
-// entries have this layout.
-//
-// Note that users can and do create map entries directly, which will also use
-// this layout.
-//
-// NOTE: sync with mini_table/decode.c.
-typedef struct {
-  // We only need 2 hasbits max, but due to alignment we'll use 8 bytes here,
-  // and the uint64_t helps make this clear.
-  uint64_t hasbits;
-  union {
-    upb_StringView str;  // For str/bytes.
-    upb_value val;       // For all other types.
-  } k;
-  union {
-    upb_StringView str;  // For str/bytes.
-    upb_value val;       // For all other types.
-  } v;
-} upb_MapEntryData;
-
-typedef struct {
-  void* internal_data;
-  upb_MapEntryData data;
-} upb_MapEntry;
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// Computes a bitmask in which the |l->required_count| lowest bits are set,
-// except that we skip the lowest bit (because upb never uses hasbit 0).
-//
-// Sample output:
-//    requiredmask(1) => 0b10 (0x2)
-//    requiredmask(5) => 0b111110 (0x3e)
-UPB_INLINE uint64_t upb_MiniTable_requiredmask(const upb_MiniTable* l) {
-  int n = l->required_count;
-  assert(0 < n && n <= 63);
-  return ((1ULL << n) - 1) << 1;
-}
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-
-#endif /* UPB_MINI_TABLE_MESSAGE_INTERNAL_H_ */
-
-// Must be last.
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// _upb_mapsorter sorts maps and provides ordered iteration over the entries.
-// Since maps can be recursive (map values can be messages which contain other
-// maps), _upb_mapsorter can contain a stack of maps.
-
-typedef struct {
-  void const** entries;
-  int size;
-  int cap;
-} _upb_mapsorter;
-
-typedef struct {
-  int start;
-  int pos;
-  int end;
-} _upb_sortedmap;
-
-UPB_INLINE void _upb_mapsorter_init(_upb_mapsorter* s) {
-  s->entries = NULL;
-  s->size = 0;
-  s->cap = 0;
-}
-
-UPB_INLINE void _upb_mapsorter_destroy(_upb_mapsorter* s) {
-  if (s->entries) free(s->entries);
-}
-
-UPB_INLINE bool _upb_sortedmap_next(_upb_mapsorter* s, const upb_Map* map,
-                                    _upb_sortedmap* sorted, upb_MapEntry* ent) {
-  if (sorted->pos == sorted->end) return false;
-  const upb_tabent* tabent = (const upb_tabent*)s->entries[sorted->pos++];
-  upb_StringView key = upb_tabstrview(tabent->key);
-  _upb_map_fromkey(key, &ent->data.k, map->key_size);
-  upb_value val = {tabent->val.val};
-  _upb_map_fromvalue(val, &ent->data.v, map->val_size);
-  return true;
-}
-
-UPB_INLINE bool _upb_sortedmap_nextext(_upb_mapsorter* s,
-                                       _upb_sortedmap* sorted,
-                                       const upb_Message_Extension** ext) {
-  if (sorted->pos == sorted->end) return false;
-  *ext = (const upb_Message_Extension*)s->entries[sorted->pos++];
-  return true;
-}
-
-UPB_INLINE void _upb_mapsorter_popmap(_upb_mapsorter* s,
-                                      _upb_sortedmap* sorted) {
-  s->size = sorted->start;
-}
-
-bool _upb_mapsorter_pushmap(_upb_mapsorter* s, upb_FieldType key_type,
-                            const upb_Map* map, _upb_sortedmap* sorted);
-
-bool _upb_mapsorter_pushexts(_upb_mapsorter* s,
-                             const upb_Message_Extension* exts, size_t count,
-                             _upb_sortedmap* sorted);
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-
-#endif /* UPB_COLLECTIONS_MAP_SORTER_INTERNAL_H_ */
-
-/*
-** Our memory representation for parsing tables and messages themselves.
-** Functions in this file are used by generated code and possibly reflection.
-**
-** The definitions in this file are internal to upb.
-**/
-
-#ifndef UPB_MESSAGE_INTERNAL_H_
-#define UPB_MESSAGE_INTERNAL_H_
-
-#include <stdlib.h>
-#include <string.h>
-
-
 #ifndef UPB_MINI_TABLE_EXTENSION_REGISTRY_H_
 #define UPB_MINI_TABLE_EXTENSION_REGISTRY_H_
 
@@ -8813,7 +8801,6 @@
 const char* upb_FileDef_Name(const upb_FileDef* f);
 const UPB_DESC(FileOptions) * upb_FileDef_Options(const upb_FileDef* f);
 const char* upb_FileDef_Package(const upb_FileDef* f);
-const char* upb_FileDef_Edition(const upb_FileDef* f);
 const upb_DefPool* upb_FileDef_Pool(const upb_FileDef* f);
 
 const upb_FileDef* upb_FileDef_PublicDependency(const upb_FileDef* f, int i);
@@ -9926,7 +9913,7 @@
 upb_ExtensionRegistry* _upb_DefPool_ExtReg(const upb_DefPool* s);
 
 bool _upb_DefPool_InsertExt(upb_DefPool* s, const upb_MiniTableExtension* ext,
-                            const upb_FieldDef* f);
+                            upb_FieldDef* f);
 bool _upb_DefPool_InsertSym(upb_DefPool* s, upb_StringView sym, upb_value v,
                             upb_Status* status);
 bool _upb_DefPool_LookupSym(const upb_DefPool* s, const char* sym, size_t size,
@@ -10052,6 +10039,23 @@
 void _upb_DefBuilder_CheckIdentSlow(upb_DefBuilder* ctx, upb_StringView name,
                                     bool full);
 
+// Verify a relative identifier string. The loop is branchless for speed.
+UPB_INLINE void _upb_DefBuilder_CheckIdentNotFull(upb_DefBuilder* ctx,
+                                                  upb_StringView name) {
+  bool good = name.size > 0;
+
+  for (size_t i = 0; i < name.size; i++) {
+    const char c = name.data[i];
+    const char d = c | 0x20;  // force lowercase
+    const bool is_alpha = (('a' <= d) & (d <= 'z')) | (c == '_');
+    const bool is_numer = ('0' <= c) & (c <= '9') & (i != 0);
+
+    good &= is_alpha | is_numer;
+  }
+
+  if (!good) _upb_DefBuilder_CheckIdentSlow(ctx, name, false);
+}
+
 // Verify a full identifier string. This is slightly more complicated than
 // verifying a relative identifier string because we must track '.' chars.
 UPB_INLINE void _upb_DefBuilder_CheckIdentFull(upb_DefBuilder* ctx,
@@ -10155,14 +10159,6 @@
 uint64_t _upb_FieldDef_Modifiers(const upb_FieldDef* f);
 void _upb_FieldDef_Resolve(upb_DefBuilder* ctx, const char* prefix,
                            upb_FieldDef* f);
-void _upb_FieldDef_BuildMiniTableExtension(upb_DefBuilder* ctx,
-                                           const upb_FieldDef* f);
-
-// Allocate and initialize an array of |n| extensions (field defs).
-upb_FieldDef* _upb_Extensions_New(
-    upb_DefBuilder* ctx, int n,
-    const UPB_DESC(FieldDescriptorProto) * const* protos, const char* prefix,
-    upb_MessageDef* m);
 
 // Allocate and initialize an array of |n| field defs.
 upb_FieldDef* _upb_FieldDefs_New(
@@ -10227,7 +10223,6 @@
 void _upb_MessageDef_InsertField(upb_DefBuilder* ctx, upb_MessageDef* m,
                                  const upb_FieldDef* f);
 bool _upb_MessageDef_IsValidExtensionNumber(const upb_MessageDef* m, int n);
-void _upb_MessageDef_CreateMiniTable(upb_DefBuilder* ctx, upb_MessageDef* m);
 void _upb_MessageDef_LinkMiniTable(upb_DefBuilder* ctx,
                                    const upb_MessageDef* m);
 void _upb_MessageDef_Resolve(upb_DefBuilder* ctx, upb_MessageDef* m);