WIP.

1 files changed, 281 insertions, 1164 deletions

diff --git a/upb/def.c b/upb/def.c
index 0c154e6..2e53cf7 100644
--- a/upb/def.c
+++ b/upb/def.c
@@ -4,9 +4,82 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
-#include "upb/structdefs.int.h"
 #include "upb/handlers.h"
 
+struct upb_fielddef {
+  union {
+    int64_t sint;
+    uint64_t uint;
+    double dbl;
+    float flt;
+    void *bytes;
+  } defaultval;
+  const upb_msgdef *msgdef;
+  union {
+    const upb_msgdef *msgdef;
+    const upb_msgdef *enumdef;
+    char *unresolved_name;
+  } sub;
+  union {
+    const upb_oneofdef *oneof;
+  }
+  uint32_t number_;
+  uint32_t selector_base;  /* Used to index into a upb::Handlers table. */
+  bool is_extension_;
+  bool lazy_;
+  bool packed_;
+  upb_descriptortype_t type_;
+  upb_label_t label_;
+};
+
+struct upb_msgdef {
+  upb_filedef *file;
+  const char *full_name;
+  uint32_t selector_count;
+  uint32_t submsg_field_count;
+
+  upb_fielddef **fields;
+  upb_oneofdef **oneofs;
+
+  /* Tables for looking up fields by number and name.  Built lazily. */
+  upb_inttable *itof;  /* int to field */
+  upb_strtable *ntof;  /* name to field/oneof */
+
+  /* Is this a map-entry message? */
+  bool map_entry;
+
+  /* TODO(haberman): proper extension ranges (there can be multiple). */
+};
+
+struct upb_enumdef {
+  upb_strtable ntoi;
+  upb_inttable iton;
+  int32_t defaultval;
+};
+
+struct upb_oneofdef {
+  const upb_msgdef *parent;
+  const char *name;
+  upb_strtable *ntof;
+  upb_inttable *itof;
+};
+
+struct upb_symtab {
+  upb_arena arena;
+  upb_strtable symtab;
+};
+
+struct upb_filedef {
+  const char *name;
+  const char *package;
+  const char *phpprefix;
+  const char *phpnamespace;
+  upb_syntax_t syntax;
+
+  upb_inttable defs;
+  upb_inttable deps;
+};
+
 typedef struct {
   size_t len;
   char str[1];  /* Null-terminated string data follows. */
@@ -66,186 +139,24 @@ static bool upb_isident(const char *str, size_t len, bool full, upb_status *s) {
   return !start;
 }
 
-static bool upb_isoneof(const upb_refcounted *def) {
-  return def->vtbl == &upb_oneofdef_vtbl;
-}
-
-static bool upb_isfield(const upb_refcounted *def) {
-  return def->vtbl == &upb_fielddef_vtbl;
-}
-
-static const upb_oneofdef *upb_trygetoneof(const upb_refcounted *def) {
-  return upb_isoneof(def) ? (const upb_oneofdef*)def : NULL;
-}
-
-static const upb_fielddef *upb_trygetfield(const upb_refcounted *def) {
-  return upb_isfield(def) ? (const upb_fielddef*)def : NULL;
-}
-
-
-/* upb_def ********************************************************************/
-
-upb_deftype_t upb_def_type(const upb_def *d) { return d->type; }
-
-const char *upb_def_fullname(const upb_def *d) { return d->fullname; }
-
-const char *upb_def_name(const upb_def *d) {
-  const char *p;
-
-  if (d->fullname == NULL) {
-    return NULL;
-  } else if ((p = strrchr(d->fullname, '.')) == NULL) {
-    /* No '.' in the name, return the full string. */
-    return d->fullname;
-  } else {
-    /* Return one past the last '.'. */
-    return p + 1;
-  }
-}
-
-bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s) {
-  UPB_ASSERT(!upb_def_isfrozen(def));
-  if (!upb_isident(fullname, strlen(fullname), true, s)) {
-    return false;
-  }
-
-  fullname = upb_gstrdup(fullname);
-  if (!fullname) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  upb_gfree((void*)def->fullname);
-  def->fullname = fullname;
+static bool upb_isoneof(const void *def) {
+  UPB_UNUSED(def);
   return true;
 }
 
-const upb_filedef *upb_def_file(const upb_def *d) { return d->file; }
-
-static bool upb_def_init(upb_def *def, upb_deftype_t type,
-                         const struct upb_refcounted_vtbl *vtbl,
-                         const void *owner) {
-  if (!upb_refcounted_init(upb_def_upcast_mutable(def), vtbl, owner)) return false;
-  def->type = type;
-  def->fullname = NULL;
-  def->came_from_user = false;
-  def->file = NULL;
+static bool upb_isfield(const void *def) {
+  UPB_UNUSED(def);
   return true;
 }
 
-static void upb_def_uninit(upb_def *def) {
-  upb_gfree((void*)def->fullname);
-}
-
-static const char *msgdef_name(const upb_msgdef *m) {
-  const char *name = upb_def_fullname(upb_msgdef_upcast(m));
-  return name ? name : "(anonymous)";
+static const upb_oneofdef *upb_trygetoneof(const void *def) {
+  return upb_isoneof(def) ? (const upb_oneofdef*)def : NULL;
 }
 
-static bool upb_validate_field(upb_fielddef *f, upb_status *s) {
-  if (upb_fielddef_name(f) == NULL || upb_fielddef_number(f) == 0) {
-    upb_status_seterrmsg(s, "fielddef must have name and number set");
-    return false;
-  }
-
-  if (!f->type_is_set_) {
-    upb_status_seterrmsg(s, "fielddef type was not initialized");
-    return false;
-  }
-
-  if (upb_fielddef_lazy(f) &&
-      upb_fielddef_descriptortype(f) != UPB_DESCRIPTOR_TYPE_MESSAGE) {
-    upb_status_seterrmsg(s,
-                         "only length-delimited submessage fields may be lazy");
-    return false;
-  }
-
-  if (upb_fielddef_hassubdef(f)) {
-    const upb_def *subdef;
-
-    if (f->subdef_is_symbolic) {
-      upb_status_seterrf(s, "field '%s.%s' has not been resolved",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-
-    subdef = upb_fielddef_subdef(f);
-    if (subdef == NULL) {
-      upb_status_seterrf(s, "field %s.%s is missing required subdef",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-
-    if (!upb_def_isfrozen(subdef) && !subdef->came_from_user) {
-      upb_status_seterrf(s,
-                         "subdef of field %s.%s is not frozen or being frozen",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-  }
-
-  if (upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-    bool has_default_name = upb_fielddef_enumhasdefaultstr(f);
-    bool has_default_number = upb_fielddef_enumhasdefaultint32(f);
-
-    /* Previously verified by upb_validate_enumdef(). */
-    UPB_ASSERT(upb_enumdef_numvals(upb_fielddef_enumsubdef(f)) > 0);
-
-    /* We've already validated that we have an associated enumdef and that it
-     * has at least one member, so at least one of these should be true.
-     * Because if the user didn't set anything, we'll pick up the enum's
-     * default, but if the user *did* set something we should at least pick up
-     * the one they set (int32 or string). */
-    UPB_ASSERT(has_default_name || has_default_number);
-
-    if (!has_default_name) {
-      upb_status_seterrf(s,
-                         "enum default for field %s.%s (%d) is not in the enum",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f),
-                         upb_fielddef_defaultint32(f));
-      return false;
-    }
-
-    if (!has_default_number) {
-      upb_status_seterrf(s,
-                         "enum default for field %s.%s (%s) is not in the enum",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f),
-                         upb_fielddef_defaultstr(f, NULL));
-      return false;
-    }
-
-    /* Lift the effective numeric default into the field's default slot, in case
-     * we were only getting it "by reference" from the enumdef. */
-    upb_fielddef_setdefaultint32(f, upb_fielddef_defaultint32(f));
-  }
-
-  /* Ensure that MapEntry submessages only appear as repeated fields, not
-   * optional/required (singular) fields. */
-  if (upb_fielddef_type(f) == UPB_TYPE_MESSAGE &&
-      upb_fielddef_msgsubdef(f) != NULL) {
-    const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
-    if (upb_msgdef_mapentry(subdef) && !upb_fielddef_isseq(f)) {
-      upb_status_seterrf(s,
-                         "Field %s refers to mapentry message but is not "
-                         "a repeated field",
-                         upb_fielddef_name(f) ? upb_fielddef_name(f) :
-                         "(unnamed)");
-      return false;
-    }
-  }
-
-  return true;
+static const upb_fielddef *upb_trygetfield(const void *def) {
+  return upb_isfield(def) ? (const upb_fielddef*)def : NULL;
 }
 
-static bool upb_validate_enumdef(const upb_enumdef *e, upb_status *s) {
-  if (upb_enumdef_numvals(e) == 0) {
-    upb_status_seterrf(s, "enum %s has no members (must have at least one)",
-                       upb_enumdef_fullname(e));
-    return false;
-  }
-
-  return true;
-}
 
 /* All submessage fields are lower than all other fields.
  * Secondly, fields are increasing in order. */
@@ -291,11 +202,7 @@ static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
       !upb_msg_field_done(&j);
       upb_msg_field_next(&j), i++) {
     upb_fielddef *f = upb_msg_iter_field(&j);
-    UPB_ASSERT(f->msg.def == m);
-    if (!upb_validate_field(f, s)) {
-      upb_gfree(fields);
-      return false;
-    }
+    UPB_ASSERT(f->msgdef == m);
     if (upb_fielddef_issubmsg(f)) {
       m->submsg_field_count++;
     }
@@ -365,6 +272,7 @@ static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
   return true;
 }
 
+#if 0
 bool _upb_def_validate(upb_def *const*defs, size_t n, upb_status *s) {
   size_t i;
 
@@ -416,73 +324,20 @@ err:
   UPB_ASSERT(!(s && upb_ok(s)));
   return false;
 }
-
-bool upb_def_freeze(upb_def *const* defs, size_t n, upb_status *s) {
-  /* Def graph contains FieldDefs between each MessageDef, so double the
-   * limit. */
-  const size_t maxdepth = UPB_MAX_MESSAGE_DEPTH * 2;
-
-  if (!_upb_def_validate(defs, n, s)) {
-    return false;
-  }
-
-
-  /* Validation all passed; freeze the objects. */
-  return upb_refcounted_freeze((upb_refcounted *const*)defs, n, s, maxdepth);
-}
+#endif
 
 
 /* upb_enumdef ****************************************************************/
 
-static void visitenum(const upb_refcounted *r, upb_refcounted_visit *visit,
-                      void *closure) {
-  const upb_enumdef *e = (const upb_enumdef*)r;
-  const upb_def *def = upb_enumdef_upcast(e);
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freeenum(upb_refcounted *r) {
-  upb_enumdef *e = (upb_enumdef*)r;
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &e->iton);
-  for( ; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    /* To clean up the upb_gstrdup() from upb_enumdef_addval(). */
-    upb_gfree(upb_value_getcstr(upb_inttable_iter_value(&i)));
-  }
-  upb_strtable_uninit(&e->ntoi);
-  upb_inttable_uninit(&e->iton);
-  upb_def_uninit(upb_enumdef_upcast_mutable(e));
-  upb_gfree(e);
-}
-
-const struct upb_refcounted_vtbl upb_enumdef_vtbl = {&visitenum, &freeenum};
-
-upb_enumdef *upb_enumdef_new(const void *owner) {
-  upb_enumdef *e = upb_gmalloc(sizeof(*e));
-  if (!e) return NULL;
-
-  if (!upb_def_init(upb_enumdef_upcast_mutable(e), UPB_DEF_ENUM,
-                    &upb_enumdef_vtbl, owner)) {
-    goto err2;
-  }
+#if 0
+bool upb_enumdef_init(upb_enumdef *e) {
+  upb_def_init(&e->base, UPB_DEF_ENUM);
 
   if (!upb_strtable_init(&e->ntoi, UPB_CTYPE_INT32)) goto err2;
   if (!upb_inttable_init(&e->iton, UPB_CTYPE_CSTR)) goto err1;
-  return e;
-
-err1:
-  upb_strtable_uninit(&e->ntoi);
-err2:
-  upb_gfree(e);
-  return NULL;
-}
-
-bool upb_enumdef_freeze(upb_enumdef *e, upb_status *status) {
-  upb_def *d = upb_enumdef_upcast_mutable(e);
-  return upb_def_freeze(&d, 1, status);
+  return true;
 }
+#endif
 
 const char *upb_enumdef_fullname(const upb_enumdef *e) {
   return upb_def_fullname(upb_enumdef_upcast(e));
@@ -492,11 +347,7 @@ const char *upb_enumdef_name(const upb_enumdef *e) {
   return upb_def_name(upb_enumdef_upcast(e));
 }
 
-bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
-                             upb_status *s) {
-  return upb_def_setfullname(upb_enumdef_upcast_mutable(e), fullname, s);
-}
-
+#if 0
 bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
                         upb_status *status) {
   char *name2;
@@ -531,12 +382,14 @@ bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
 
   return true;
 }
+#endif
 
 int32_t upb_enumdef_default(const upb_enumdef *e) {
   UPB_ASSERT(upb_enumdef_iton(e, e->defaultval));
   return e->defaultval;
 }
 
+#if 0
 bool upb_enumdef_setdefault(upb_enumdef *e, int32_t val, upb_status *s) {
   UPB_ASSERT(!upb_enumdef_isfrozen(e));
   if (!upb_enumdef_iton(e, val)) {
@@ -546,6 +399,7 @@ bool upb_enumdef_setdefault(upb_enumdef *e, int32_t val, upb_status *s) {
   e->defaultval = val;
   return true;
 }
+#endif
 
 int upb_enumdef_numvals(const upb_enumdef *e) {
   return upb_strtable_count(&e->ntoi);
@@ -588,110 +442,19 @@ int32_t upb_enum_iter_number(upb_enum_iter *iter) {
 
 static void upb_fielddef_init_default(upb_fielddef *f);
 
-static void upb_fielddef_uninit_default(upb_fielddef *f) {
-  if (f->type_is_set_ && f->default_is_string && f->defaultval.bytes)
-    freestr(f->defaultval.bytes);
-}
-
 const char *upb_fielddef_fullname(const upb_fielddef *e) {
   return upb_def_fullname(upb_fielddef_upcast(e));
 }
 
-static void visitfield(const upb_refcounted *r, upb_refcounted_visit *visit,
-                       void *closure) {
-  const upb_fielddef *f = (const upb_fielddef*)r;
-  const upb_def *def = upb_fielddef_upcast(f);
-  if (upb_fielddef_containingtype(f)) {
-    visit(r, upb_msgdef_upcast2(upb_fielddef_containingtype(f)), closure);
-  }
-  if (upb_fielddef_containingoneof(f)) {
-    visit(r, upb_oneofdef_upcast(upb_fielddef_containingoneof(f)), closure);
-  }
-  if (upb_fielddef_subdef(f)) {
-    visit(r, upb_def_upcast(upb_fielddef_subdef(f)), closure);
-  }
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freefield(upb_refcounted *r) {
-  upb_fielddef *f = (upb_fielddef*)r;
-  upb_fielddef_uninit_default(f);
-  if (f->subdef_is_symbolic)
-    upb_gfree(f->sub.name);
-  upb_def_uninit(upb_fielddef_upcast_mutable(f));
-  upb_gfree(f);
-}
-
-static const char *enumdefaultstr(const upb_fielddef *f) {
-  const upb_enumdef *e;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  e = upb_fielddef_enumsubdef(f);
-  if (f->default_is_string && f->defaultval.bytes) {
-    /* Default was explicitly set as a string. */
-    str_t *s = f->defaultval.bytes;
-    return s->str;
-  } else if (e) {
-    if (!f->default_is_string) {
-      /* Default was explicitly set as an integer; look it up in enumdef. */
-      const char *name = upb_enumdef_iton(e, f->defaultval.sint);
-      if (name) {
-        return name;
-      }
-    } else {
-      /* Default is completely unset; pull enumdef default. */
-      if (upb_enumdef_numvals(e) > 0) {
-        const char *name = upb_enumdef_iton(e, upb_enumdef_default(e));
-        UPB_ASSERT(name);
-        return name;
-      }
-    }
-  }
-  return NULL;
-}
-
-static bool enumdefaultint32(const upb_fielddef *f, int32_t *val) {
-  const upb_enumdef *e;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  e = upb_fielddef_enumsubdef(f);
-  if (!f->default_is_string) {
-    /* Default was explicitly set as an integer. */
-    *val = f->defaultval.sint;
-    return true;
-  } else if (e) {
-    if (f->defaultval.bytes) {
-      /* Default was explicitly set as a str; try to lookup corresponding int. */
-      str_t *s = f->defaultval.bytes;
-      if (upb_enumdef_ntoiz(e, s->str, val)) {
-        return true;
-      }
-    } else {
-      /* Default is unset; try to pull in enumdef default. */
-      if (upb_enumdef_numvals(e) > 0) {
-        *val = upb_enumdef_default(e);
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-const struct upb_refcounted_vtbl upb_fielddef_vtbl = {visitfield, freefield};
-
+#if 0
 upb_fielddef *upb_fielddef_new(const void *o) {
   upb_fielddef *f = upb_gmalloc(sizeof(*f));
   if (!f) return NULL;
-  if (!upb_def_init(upb_fielddef_upcast_mutable(f), UPB_DEF_FIELD,
-                    &upb_fielddef_vtbl, o)) {
-    upb_gfree(f);
-    return NULL;
-  }
+  upb_def_init(&f->base, UPB_DEF_FIELD);
   f->msg.def = NULL;
   f->sub.def = NULL;
   f->oneof = NULL;
   f->subdef_is_symbolic = false;
-  f->msg_is_symbolic = false;
   f->label_ = UPB_LABEL_OPTIONAL;
   f->type_ = UPB_TYPE_INT32;
   f->number_ = 0;
@@ -712,13 +475,9 @@ upb_fielddef *upb_fielddef_new(const void *o) {
   f->intfmt = UPB_INTFMT_VARIABLE;
   return f;
 }
-
-bool upb_fielddef_typeisset(const upb_fielddef *f) {
-  return f->type_is_set_;
-}
+#endif
 
 upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f) {
-  UPB_ASSERT(f->type_is_set_);
   return f->type_;
 }
 
@@ -798,60 +557,16 @@ size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len) {
 }
 
 const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f) {
-  return f->msg_is_symbolic ? NULL : f->msg.def;
+  return f->msgdef;
 }
 
 const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f) {
   return f->oneof;
 }
 
-upb_msgdef *upb_fielddef_containingtype_mutable(upb_fielddef *f) {
-  return (upb_msgdef*)upb_fielddef_containingtype(f);
-}
-
-const char *upb_fielddef_containingtypename(upb_fielddef *f) {
-  return f->msg_is_symbolic ? f->msg.name : NULL;
-}
-
-static void release_containingtype(upb_fielddef *f) {
-  if (f->msg_is_symbolic) upb_gfree(f->msg.name);
-}
-
-bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
-                                        upb_status *s) {
-  char *name_copy;
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  if (upb_fielddef_containingtype(f)) {
-    upb_status_seterrmsg(s, "field has already been added to a message.");
-    return false;
-  }
-  /* TODO: validate name (upb_isident() doesn't quite work atm because this name
-   * may have a leading "."). */
-
-  name_copy = upb_gstrdup(name);
-  if (!name_copy) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  release_containingtype(f);
-  f->msg.name = name_copy;
-  f->msg_is_symbolic = true;
-  return true;
-}
-
-bool upb_fielddef_setname(upb_fielddef *f, const char *name, upb_status *s) {
-  if (upb_fielddef_containingtype(f) || upb_fielddef_containingoneof(f)) {
-    upb_status_seterrmsg(s, "Already added to message or oneof");
-    return false;
-  }
-  return upb_def_setfullname(upb_fielddef_upcast_mutable(f), name, s);
-}
-
-static void chkdefaulttype(const upb_fielddef *f, upb_fieldtype_t type) {
+static void chkdefaulttype(const upb_fielddef *f, int ctype) {
   UPB_UNUSED(f);
-  UPB_UNUSED(type);
-  UPB_ASSERT(f->type_is_set_ && upb_fielddef_type(f) == type);
+  UPB_UNUSED(ctype);
 }
 
 int64_t upb_fielddef_defaultint64(const upb_fielddef *f) {
@@ -860,15 +575,8 @@ int64_t upb_fielddef_defaultint64(const upb_fielddef *f) {
 }
 
 int32_t upb_fielddef_defaultint32(const upb_fielddef *f) {
-  if (f->type_is_set_ && upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-    int32_t val;
-    bool ok = enumdefaultint32(f, &val);
-    UPB_ASSERT(ok);
-    return val;
-  } else {
-    chkdefaulttype(f, UPB_TYPE_INT32);
-    return f->defaultval.sint;
-  }
+  chkdefaulttype(f, UPB_TYPE_INT32);
+  return f->defaultval.sint;
 }
 
 uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f) {
@@ -943,10 +651,6 @@ static void upb_fielddef_init_default(upb_fielddef *f) {
   }
 }
 
-const upb_def *upb_fielddef_subdef(const upb_fielddef *f) {
-  return f->subdef_is_symbolic ? NULL : f->sub.def;
-}
-
 const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f) {
   const upb_def *def = upb_fielddef_subdef(f);
   return def ? upb_dyncast_msgdef(def) : NULL;
@@ -957,10 +661,6 @@ const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f) {
   return def ? upb_dyncast_enumdef(def) : NULL;
 }
 
-upb_def *upb_fielddef_subdef_mutable(upb_fielddef *f) {
-  return (upb_def*)upb_fielddef_subdef(f);
-}
-
 const char *upb_fielddef_subdefname(const upb_fielddef *f) {
   if (f->subdef_is_symbolic) {
     return f->sub.name;
@@ -985,237 +685,8 @@ bool upb_fielddef_setnumber(upb_fielddef *f, uint32_t number, upb_status *s) {
   return true;
 }
 
-void upb_fielddef_settype(upb_fielddef *f, upb_fieldtype_t type) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checktype(type));
-  upb_fielddef_uninit_default(f);
-  f->type_ = type;
-  f->type_is_set_ = true;
-  upb_fielddef_init_default(f);
-}
-
-void upb_fielddef_setdescriptortype(upb_fielddef *f, int type) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  switch (type) {
-    case UPB_DESCRIPTOR_TYPE_DOUBLE:
-      upb_fielddef_settype(f, UPB_TYPE_DOUBLE);
-      break;
-    case UPB_DESCRIPTOR_TYPE_FLOAT:
-      upb_fielddef_settype(f, UPB_TYPE_FLOAT);
-      break;
-    case UPB_DESCRIPTOR_TYPE_INT64:
-    case UPB_DESCRIPTOR_TYPE_SFIXED64:
-    case UPB_DESCRIPTOR_TYPE_SINT64:
-      upb_fielddef_settype(f, UPB_TYPE_INT64);
-      break;
-    case UPB_DESCRIPTOR_TYPE_UINT64:
-    case UPB_DESCRIPTOR_TYPE_FIXED64:
-      upb_fielddef_settype(f, UPB_TYPE_UINT64);
-      break;
-    case UPB_DESCRIPTOR_TYPE_INT32:
-    case UPB_DESCRIPTOR_TYPE_SFIXED32:
-    case UPB_DESCRIPTOR_TYPE_SINT32:
-      upb_fielddef_settype(f, UPB_TYPE_INT32);
-      break;
-    case UPB_DESCRIPTOR_TYPE_UINT32:
-    case UPB_DESCRIPTOR_TYPE_FIXED32:
-      upb_fielddef_settype(f, UPB_TYPE_UINT32);
-      break;
-    case UPB_DESCRIPTOR_TYPE_BOOL:
-      upb_fielddef_settype(f, UPB_TYPE_BOOL);
-      break;
-    case UPB_DESCRIPTOR_TYPE_STRING:
-      upb_fielddef_settype(f, UPB_TYPE_STRING);
-      break;
-    case UPB_DESCRIPTOR_TYPE_BYTES:
-      upb_fielddef_settype(f, UPB_TYPE_BYTES);
-      break;
-    case UPB_DESCRIPTOR_TYPE_GROUP:
-    case UPB_DESCRIPTOR_TYPE_MESSAGE:
-      upb_fielddef_settype(f, UPB_TYPE_MESSAGE);
-      break;
-    case UPB_DESCRIPTOR_TYPE_ENUM:
-      upb_fielddef_settype(f, UPB_TYPE_ENUM);
-      break;
-    default: UPB_ASSERT(false);
-  }
-
-  if (type == UPB_DESCRIPTOR_TYPE_FIXED64 ||
-      type == UPB_DESCRIPTOR_TYPE_FIXED32 ||
-      type == UPB_DESCRIPTOR_TYPE_SFIXED64 ||
-      type == UPB_DESCRIPTOR_TYPE_SFIXED32) {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_FIXED);
-  } else if (type == UPB_DESCRIPTOR_TYPE_SINT64 ||
-             type == UPB_DESCRIPTOR_TYPE_SINT32) {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_ZIGZAG);
-  } else {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_VARIABLE);
-  }
-
-  upb_fielddef_settagdelim(f, type == UPB_DESCRIPTOR_TYPE_GROUP);
-}
-
 upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f) {
-  switch (upb_fielddef_type(f)) {
-    case UPB_TYPE_FLOAT:  return UPB_DESCRIPTOR_TYPE_FLOAT;
-    case UPB_TYPE_DOUBLE: return UPB_DESCRIPTOR_TYPE_DOUBLE;
-    case UPB_TYPE_BOOL:   return UPB_DESCRIPTOR_TYPE_BOOL;
-    case UPB_TYPE_STRING: return UPB_DESCRIPTOR_TYPE_STRING;
-    case UPB_TYPE_BYTES:  return UPB_DESCRIPTOR_TYPE_BYTES;
-    case UPB_TYPE_ENUM:   return UPB_DESCRIPTOR_TYPE_ENUM;
-    case UPB_TYPE_INT32:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_INT32;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_SFIXED32;
-        case UPB_INTFMT_ZIGZAG:   return UPB_DESCRIPTOR_TYPE_SINT32;
-      }
-    case UPB_TYPE_INT64:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_INT64;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_SFIXED64;
-        case UPB_INTFMT_ZIGZAG:   return UPB_DESCRIPTOR_TYPE_SINT64;
-      }
-    case UPB_TYPE_UINT32:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_UINT32;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_FIXED32;
-        case UPB_INTFMT_ZIGZAG:   return -1;
-      }
-    case UPB_TYPE_UINT64:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_UINT64;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_FIXED64;
-        case UPB_INTFMT_ZIGZAG:   return -1;
-      }
-    case UPB_TYPE_MESSAGE:
-      return upb_fielddef_istagdelim(f) ?
-          UPB_DESCRIPTOR_TYPE_GROUP : UPB_DESCRIPTOR_TYPE_MESSAGE;
-  }
-  return 0;
-}
-
-void upb_fielddef_setisextension(upb_fielddef *f, bool is_extension) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->is_extension_ = is_extension;
-}
-
-void upb_fielddef_setlazy(upb_fielddef *f, bool lazy) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->lazy_ = lazy;
-}
-
-void upb_fielddef_setpacked(upb_fielddef *f, bool packed) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->packed_ = packed;
-}
-
-void upb_fielddef_setlabel(upb_fielddef *f, upb_label_t label) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checklabel(label));
-  f->label_ = label;
-}
-
-void upb_fielddef_setintfmt(upb_fielddef *f, upb_intfmt_t fmt) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checkintfmt(fmt));
-  f->intfmt = fmt;
-}
-
-void upb_fielddef_settagdelim(upb_fielddef *f, bool tag_delim) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->tagdelim = tag_delim;
-  f->tagdelim = tag_delim;
-}
-
-static bool checksetdefault(upb_fielddef *f, upb_fieldtype_t type) {
-  if (!f->type_is_set_ || upb_fielddef_isfrozen(f) ||
-      upb_fielddef_type(f) != type) {
-    UPB_ASSERT(false);
-    return false;
-  }
-  if (f->default_is_string) {
-    str_t *s = f->defaultval.bytes;
-    UPB_ASSERT(s || type == UPB_TYPE_ENUM);
-    if (s) freestr(s);
-  }
-  f->default_is_string = false;
-  return true;
-}
-
-void upb_fielddef_setdefaultint64(upb_fielddef *f, int64_t value) {
-  if (checksetdefault(f, UPB_TYPE_INT64))
-    f->defaultval.sint = value;
-}
-
-void upb_fielddef_setdefaultint32(upb_fielddef *f, int32_t value) {
-  if ((upb_fielddef_type(f) == UPB_TYPE_ENUM &&
-       checksetdefault(f, UPB_TYPE_ENUM)) ||
-      checksetdefault(f, UPB_TYPE_INT32)) {
-    f->defaultval.sint = value;
-  }
-}
-
-void upb_fielddef_setdefaultuint64(upb_fielddef *f, uint64_t value) {
-  if (checksetdefault(f, UPB_TYPE_UINT64))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultuint32(upb_fielddef *f, uint32_t value) {
-  if (checksetdefault(f, UPB_TYPE_UINT32))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultbool(upb_fielddef *f, bool value) {
-  if (checksetdefault(f, UPB_TYPE_BOOL))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultfloat(upb_fielddef *f, float value) {
-  if (checksetdefault(f, UPB_TYPE_FLOAT))
-    f->defaultval.flt = value;
-}
-
-void upb_fielddef_setdefaultdouble(upb_fielddef *f, double value) {
-  if (checksetdefault(f, UPB_TYPE_DOUBLE))
-    f->defaultval.dbl = value;
-}
-
-bool upb_fielddef_setdefaultstr(upb_fielddef *f, const void *str, size_t len,
-                                upb_status *s) {
-  str_t *str2;
-  UPB_ASSERT(upb_fielddef_isstring(f) || f->type_ == UPB_TYPE_ENUM);
-  if (f->type_ == UPB_TYPE_ENUM && !upb_isident(str, len, false, s))
-    return false;
-
-  if (f->default_is_string) {
-    str_t *s = f->defaultval.bytes;
-    UPB_ASSERT(s || f->type_ == UPB_TYPE_ENUM);
-    if (s) freestr(s);
-  } else {
-    UPB_ASSERT(f->type_ == UPB_TYPE_ENUM);
-  }
-
-  str2 = newstr(str, len);
-  f->defaultval.bytes = str2;
-  f->default_is_string = true;
-  return true;
-}
-
-void upb_fielddef_setdefaultcstr(upb_fielddef *f, const char *str,
-                                 upb_status *s) {
-  UPB_ASSERT(f->type_is_set_);
-  upb_fielddef_setdefaultstr(f, str, str ? strlen(str) : 0, s);
-}
-
-bool upb_fielddef_enumhasdefaultint32(const upb_fielddef *f) {
-  int32_t val;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  return enumdefaultint32(f, &val);
-}
-
-bool upb_fielddef_enumhasdefaultstr(const upb_fielddef *f) {
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  return enumdefaultstr(f) != NULL;
+  return f->type;
 }
 
 static bool upb_subdef_typecheck(upb_fielddef *f, const upb_def *subdef,
@@ -1234,59 +705,6 @@ static bool upb_subdef_typecheck(upb_fielddef *f, const upb_def *subdef,
   }
 }
 
-static void release_subdef(upb_fielddef *f) {
-  if (f->subdef_is_symbolic) {
-    upb_gfree(f->sub.name);
-  } else if (f->sub.def) {
-    upb_unref2(f->sub.def, f);
-  }
-}
-
-bool upb_fielddef_setsubdef(upb_fielddef *f, const upb_def *subdef,
-                            upb_status *s) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_hassubdef(f));
-  if (subdef && !upb_subdef_typecheck(f, subdef, s)) return false;
-  release_subdef(f);
-  f->sub.def = subdef;
-  f->subdef_is_symbolic = false;
-  if (f->sub.def) upb_ref2(f->sub.def, f);
-  return true;
-}
-
-bool upb_fielddef_setmsgsubdef(upb_fielddef *f, const upb_msgdef *subdef,
-                               upb_status *s) {
-  return upb_fielddef_setsubdef(f, upb_msgdef_upcast(subdef), s);
-}
-
-bool upb_fielddef_setenumsubdef(upb_fielddef *f, const upb_enumdef *subdef,
-                                upb_status *s) {
-  return upb_fielddef_setsubdef(f, upb_enumdef_upcast(subdef), s);
-}
-
-bool upb_fielddef_setsubdefname(upb_fielddef *f, const char *name,
-                                upb_status *s) {
-  char *name_copy;
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  if (!upb_fielddef_hassubdef(f)) {
-    upb_status_seterrmsg(s, "field type does not accept a subdef");
-    return false;
-  }
-
-  name_copy = upb_gstrdup(name);
-  if (!name_copy) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  /* TODO: validate name (upb_isident() doesn't quite work atm because this name
-   * may have a leading "."). */
-  release_subdef(f);
-  f->sub.name = name_copy;
-  f->subdef_is_symbolic = true;
-  return true;
-}
-
 bool upb_fielddef_issubmsg(const upb_fielddef *f) {
   return upb_fielddef_type(f) == UPB_TYPE_MESSAGE;
 }
@@ -1343,66 +761,6 @@ static const char *kValueFullMessageName = "google.protobuf.Value";
 static const char *kListValueFullMessageName = "google.protobuf.ListValue";
 static const char *kStructFullMessageName = "google.protobuf.Struct";
 
-static void visitmsg(const upb_refcounted *r, upb_refcounted_visit *visit,
-                     void *closure) {
-  upb_msg_oneof_iter o;
-  const upb_msgdef *m = (const upb_msgdef*)r;
-  const upb_def *def = upb_msgdef_upcast(m);
-  upb_msg_field_iter i;
-  for(upb_msg_field_begin(&i, m);
-      !upb_msg_field_done(&i);
-      upb_msg_field_next(&i)) {
-    upb_fielddef *f = upb_msg_iter_field(&i);
-    visit(r, upb_fielddef_upcast2(f), closure);
-  }
-  for(upb_msg_oneof_begin(&o, m);
-      !upb_msg_oneof_done(&o);
-      upb_msg_oneof_next(&o)) {
-    upb_oneofdef *f = upb_msg_iter_oneof(&o);
-    visit(r, upb_oneofdef_upcast(f), closure);
-  }
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freemsg(upb_refcounted *r) {
-  upb_msgdef *m = (upb_msgdef*)r;
-  upb_strtable_uninit(&m->ntof);
-  upb_inttable_uninit(&m->itof);
-  upb_def_uninit(upb_msgdef_upcast_mutable(m));
-  upb_gfree(m);
-}
-
-const struct upb_refcounted_vtbl upb_msgdef_vtbl = {visitmsg, freemsg};
-
-upb_msgdef *upb_msgdef_new(const void *owner) {
-  upb_msgdef *m = upb_gmalloc(sizeof(*m));
-  if (!m) return NULL;
-
-  if (!upb_def_init(upb_msgdef_upcast_mutable(m), UPB_DEF_MSG, &upb_msgdef_vtbl,
-                    owner)) {
-    goto err2;
-  }
-
-  if (!upb_inttable_init(&m->itof, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_strtable_init(&m->ntof, UPB_CTYPE_PTR)) goto err1;
-  m->map_entry = false;
-  m->syntax = UPB_SYNTAX_PROTO2;
-  return m;
-
-err1:
-  upb_inttable_uninit(&m->itof);
-err2:
-  upb_gfree(m);
-  return NULL;
-}
-
-bool upb_msgdef_freeze(upb_msgdef *m, upb_status *status) {
-  upb_def *d = upb_msgdef_upcast_mutable(m);
-  return upb_def_freeze(&d, 1, status);
-}
-
 const char *upb_msgdef_fullname(const upb_msgdef *m) {
   return upb_def_fullname(upb_msgdef_upcast(m));
 }
@@ -1411,20 +769,6 @@ const char *upb_msgdef_name(const upb_msgdef *m) {
   return upb_def_name(upb_msgdef_upcast(m));
 }
 
-bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname,
-                            upb_status *s) {
-  return upb_def_setfullname(upb_msgdef_upcast_mutable(m), fullname, s);
-}
-
-bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax) {
-  if (syntax != UPB_SYNTAX_PROTO2 && syntax != UPB_SYNTAX_PROTO3) {
-    return false;
-  }
-
-  m->syntax = syntax;
-  return true;
-}
-
 upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m) {
   return m->syntax;
 }
@@ -1449,17 +793,6 @@ static bool check_field_add(const upb_msgdef *m, const upb_fielddef *f,
   return true;
 }
 
-static void add_field(upb_msgdef *m, upb_fielddef *f, const void *ref_donor) {
-  release_containingtype(f);
-  f->msg.def = m;
-  f->msg_is_symbolic = false;
-  upb_inttable_insert(&m->itof, upb_fielddef_number(f), upb_value_ptr(f));
-  upb_strtable_insert(&m->ntof, upb_fielddef_name(f), upb_value_ptr(f));
-  upb_ref2(f, m);
-  upb_ref2(m, f);
-  if (ref_donor) upb_fielddef_unref(f, ref_donor);
-}
-
 bool upb_msgdef_addfield(upb_msgdef *m, upb_fielddef *f, const void *ref_donor,
                          upb_status *s) {
   /* TODO: extensions need to have a separate namespace, because proto2 allows a
@@ -1590,11 +923,6 @@ int upb_msgdef_numoneofs(const upb_msgdef *m) {
   return upb_strtable_count(&m->ntof) - upb_inttable_count(&m->itof);
 }
 
-void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry) {
-  UPB_ASSERT(!upb_msgdef_isfrozen(m));
-  m->map_entry = map_entry;
-}
-
 bool upb_msgdef_mapentry(const upb_msgdef *m) {
   return m->map_entry;
 }
@@ -1668,80 +996,8 @@ void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter *iter) {
 
 /* upb_oneofdef ***************************************************************/
 
-static void visitoneof(const upb_refcounted *r, upb_refcounted_visit *visit,
-                       void *closure) {
-  const upb_oneofdef *o = (const upb_oneofdef*)r;
-  upb_oneof_iter i;
-  for (upb_oneof_begin(&i, o); !upb_oneof_done(&i); upb_oneof_next(&i)) {
-    const upb_fielddef *f = upb_oneof_iter_field(&i);
-    visit(r, upb_fielddef_upcast2(f), closure);
-  }
-  if (o->parent) {
-    visit(r, upb_msgdef_upcast2(o->parent), closure);
-  }
-}
-
-static void freeoneof(upb_refcounted *r) {
-  upb_oneofdef *o = (upb_oneofdef*)r;
-  upb_strtable_uninit(&o->ntof);
-  upb_inttable_uninit(&o->itof);
-  upb_gfree((void*)o->name);
-  upb_gfree(o);
-}
-
-const struct upb_refcounted_vtbl upb_oneofdef_vtbl = {visitoneof, freeoneof};
-
-upb_oneofdef *upb_oneofdef_new(const void *owner) {
-  upb_oneofdef *o = upb_gmalloc(sizeof(*o));
-
-  if (!o) {
-    return NULL;
-  }
-
-  o->parent = NULL;
-  o->name = NULL;
-
-  if (!upb_refcounted_init(upb_oneofdef_upcast_mutable(o), &upb_oneofdef_vtbl,
-                           owner)) {
-    goto err2;
-  }
-
-  if (!upb_inttable_init(&o->itof, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_strtable_init(&o->ntof, UPB_CTYPE_PTR)) goto err1;
-
-  return o;
-
-err1:
-  upb_inttable_uninit(&o->itof);
-err2:
-  upb_gfree(o);
-  return NULL;
-}
-
 const char *upb_oneofdef_name(const upb_oneofdef *o) { return o->name; }
 
-bool upb_oneofdef_setname(upb_oneofdef *o, const char *name, upb_status *s) {
-  UPB_ASSERT(!upb_oneofdef_isfrozen(o));
-  if (upb_oneofdef_containingtype(o)) {
-    upb_status_seterrmsg(s, "oneof already added to a message");
-    return false;
-  }
-
-  if (!upb_isident(name, strlen(name), true, s)) {
-    return false;
-  }
-
-  name = upb_gstrdup(name);
-  if (!name) {
-    upb_status_seterrmsg(s, "One of memory");
-    return false;
-  }
-
-  upb_gfree((void*)o->name);
-  o->name = name;
-  return true;
-}
-
 const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o) {
   return o->parent;
 }
@@ -1818,7 +1074,6 @@ bool upb_oneofdef_addfield(upb_oneofdef *o, upb_fielddef *f,
     }
   }
 
-  release_containingtype(f);
   f->oneof = o;
   upb_inttable_insert(&o->itof, upb_fielddef_number(f), upb_value_ptr(f));
   upb_strtable_insert(&o->ntof, upb_fielddef_name(f), upb_value_ptr(f));
@@ -1864,35 +1119,6 @@ void upb_oneof_iter_setdone(upb_oneof_iter *iter) {
 
 /* upb_filedef ****************************************************************/
 
-static void visitfiledef(const upb_refcounted *r, upb_refcounted_visit *visit,
-                         void *closure) {
-  const upb_filedef *f = (const upb_filedef*)r;
-  size_t i;
-
-  for(i = 0; i < upb_filedef_defcount(f); i++) {
-    visit(r, upb_def_upcast(upb_filedef_def(f, i)), closure);
-  }
-}
-
-static void freefiledef(upb_refcounted *r) {
-  upb_filedef *f = (upb_filedef*)r;
-  size_t i;
-
-  for(i = 0; i < upb_filedef_depcount(f); i++) {
-    upb_filedef_unref(upb_filedef_dep(f, i), f);
-  }
-
-  upb_inttable_uninit(&f->defs);
-  upb_inttable_uninit(&f->deps);
-  upb_gfree((void*)f->name);
-  upb_gfree((void*)f->package);
-  upb_gfree((void*)f->phpprefix);
-  upb_gfree((void*)f->phpnamespace);
-  upb_gfree(f);
-}
-
-const struct upb_refcounted_vtbl upb_filedef_vtbl = {visitfiledef, freefiledef};
-
 upb_filedef *upb_filedef_new(const void *owner) {
   upb_filedef *f = upb_gmalloc(sizeof(*f));
 
@@ -1906,11 +1132,6 @@ upb_filedef *upb_filedef_new(const void *owner) {
   f->phpnamespace = NULL;
   f->syntax = UPB_SYNTAX_PROTO2;
 
-  if (!upb_refcounted_init(upb_filedef_upcast_mutable(f), &upb_filedef_vtbl,
-                           owner)) {
-    goto err;
-  }
-
   if (!upb_inttable_init(&f->defs, UPB_CTYPE_CONSTPTR)) {
     goto err;
   }
@@ -1978,122 +1199,8 @@ const upb_filedef *upb_filedef_dep(const upb_filedef *f, size_t i) {
   }
 }
 
-bool upb_filedef_setname(upb_filedef *f, const char *name, upb_status *s) {
-  name = upb_gstrdup(name);
-  if (!name) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->name);
-  f->name = name;
-  return true;
-}
-
-bool upb_filedef_setpackage(upb_filedef *f, const char *package,
-                            upb_status *s) {
-  if (!upb_isident(package, strlen(package), true, s)) return false;
-  package = upb_gstrdup(package);
-  if (!package) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->package);
-  f->package = package;
-  return true;
-}
-
-bool upb_filedef_setphpprefix(upb_filedef *f, const char *phpprefix,
-                              upb_status *s) {
-  phpprefix = upb_gstrdup(phpprefix);
-  if (!phpprefix) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->phpprefix);
-  f->phpprefix = phpprefix;
-  return true;
-}
-
-bool upb_filedef_setphpnamespace(upb_filedef *f, const char *phpnamespace,
-                                 upb_status *s) {
-  phpnamespace = upb_gstrdup(phpnamespace);
-  if (!phpnamespace) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->phpnamespace);
-  f->phpnamespace = phpnamespace;
-  return true;
-}
-
-bool upb_filedef_setsyntax(upb_filedef *f, upb_syntax_t syntax,
-                           upb_status *s) {
-  UPB_UNUSED(s);
-  if (syntax != UPB_SYNTAX_PROTO2 &&
-      syntax != UPB_SYNTAX_PROTO3) {
-    upb_status_seterrmsg(s, "Unknown syntax value.");
-    return false;
-  }
-  f->syntax = syntax;
-
-  {
-    /* Set all messages in this file to match. */
-    size_t i;
-    for (i = 0; i < upb_filedef_defcount(f); i++) {
-      /* Casting const away is safe since all defs in mutable filedef must
-       * also be mutable. */
-      upb_def *def = (upb_def*)upb_filedef_def(f, i);
-
-      upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
-      if (m) {
-        m->syntax = syntax;
-      }
-    }
-  }
-
-  return true;
-}
-
-bool upb_filedef_adddef(upb_filedef *f, upb_def *def, const void *ref_donor,
-                        upb_status *s) {
-  if (def->file) {
-    upb_status_seterrmsg(s, "Def is already part of another filedef.");
-    return false;
-  }
-
-  if (upb_inttable_push(&f->defs, upb_value_constptr(def))) {
-    def->file = f;
-    upb_ref2(def, f);
-    upb_ref2(f, def);
-    if (ref_donor) upb_def_unref(def, ref_donor);
-    if (def->type == UPB_DEF_MSG) {
-      upb_downcast_msgdef_mutable(def)->syntax = f->syntax;
-    }
-    return true;
-  } else {
-    upb_upberr_setoom(s);
-    return false;
-  }
-}
-
-bool upb_filedef_adddep(upb_filedef *f, const upb_filedef *dep) {
-  if (upb_inttable_push(&f->deps, upb_value_constptr(dep))) {
-    /* Regular ref instead of ref2 because files can't form cycles. */
-    upb_filedef_ref(dep, f);
-    return true;
-  } else {
-    return false;
-  }
-}
-
 void upb_symtab_free(upb_symtab *s) {
-  upb_strtable_iter i;
-  upb_strtable_begin(&i, &s->symtab);
-  for (; !upb_strtable_done(&i); upb_strtable_next(&i)) {
-    const upb_def *def = upb_value_getptr(upb_strtable_iter_value(&i));
-    upb_def_unref(def, s);
-  }
-  upb_strtable_uninit(&s->symtab);
+  upb_arena_uninit(&s->arena);
   upb_gfree(s);
 }
 
@@ -2103,7 +1210,17 @@ upb_symtab *upb_symtab_new() {
     return NULL;
   }
 
-  upb_strtable_init(&s->symtab, UPB_CTYPE_PTR);
+  if (!upb_arena_init(&s->arena)) goto err2;
+  if (!upb_strtable_init2(&s->symtab, UPB_CTYPE_PTR,
+                          upb_arena_alloc(&s->arena))) {
+    goto err1;
+  }
+  return s;
+
+err1:
+  upb_arena_uninit(&s->arena);
+err2:
+  upb_gfree(s);
   return s;
 }
 
@@ -2153,77 +1270,7 @@ const upb_def *upb_symtab_resolve(const upb_symtab *s, const char *base,
   return ret;
 }
 
-/* TODO(haberman): we need a lot more testing of error conditions. */
-static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
-                       void *ref_donor, upb_refcounted *freeze_also,
-                       upb_status *status) {
-  size_t i;
-  size_t add_n;
-  size_t freeze_n;
-  upb_strtable_iter iter;
-  upb_refcounted **add_objs = NULL;
-  upb_def **add_defs = NULL;
-  size_t add_objs_size;
-  upb_strtable addtab;
-
-  if (n == 0 && !freeze_also) {
-    return true;
-  }
-
-  if (!upb_strtable_init(&addtab, UPB_CTYPE_PTR)) {
-    upb_status_seterrmsg(status, "out of memory");
-    return false;
-  }
-
-  /* Add new defs to our "add" set. */
-  for (i = 0; i < n; i++) {
-    upb_def *def = defs[i];
-    const char *fullname;
-    upb_fielddef *f;
-
-    if (upb_def_isfrozen(def)) {
-      upb_status_seterrmsg(status, "added defs must be mutable");
-      goto err;
-    }
-    UPB_ASSERT(!upb_def_isfrozen(def));
-    fullname = upb_def_fullname(def);
-    if (!fullname) {
-      upb_status_seterrmsg(
-          status, "Anonymous defs cannot be added to a symtab");
-      goto err;
-    }
-
-    f = upb_dyncast_fielddef_mutable(def);
-
-    if (f) {
-      if (!upb_fielddef_containingtypename(f)) {
-        upb_status_seterrmsg(status,
-                             "Standalone fielddefs must have a containing type "
-                             "(extendee) name set");
-        goto err;
-      }
-    } else {
-      if (upb_strtable_lookup(&addtab, fullname, NULL)) {
-        upb_status_seterrf(status, "Conflicting defs named '%s'", fullname);
-        goto err;
-      }
-      if (upb_strtable_lookup(&s->symtab, fullname, NULL)) {
-        upb_status_seterrf(status, "Symtab already has a def named '%s'",
-                           fullname);
-        goto err;
-      }
-      if (!upb_strtable_insert(&addtab, fullname, upb_value_ptr(def)))
-        goto oom_err;
-      upb_def_donateref(def, ref_donor, s);
-    }
-
-    if (upb_dyncast_fielddef_mutable(def)) {
-      /* TODO(haberman): allow adding extensions attached to files. */
-      upb_status_seterrf(status, "Can't add extensions to symtab.\n");
-      goto err;
-    }
-  }
-
+#if 0
   /* Now using the table, resolve symbolic references for subdefs. */
   upb_strtable_begin(&iter, &addtab);
   for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
@@ -2258,132 +1305,202 @@ static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
       }
     }
   }
+#endif
 
-  /* We need an array of the defs in addtab, for passing to
-   * upb_refcounted_freeze(). */
-  add_objs_size = upb_strtable_count(&addtab);
-  if (freeze_also) {
-    add_objs_size++;
-  }
+static bool create_oneofdef(
+    upb_symtab *s, const google_protobuf_OneofDescriptorProto *oneof_proto,
+    upb_msgdef *m, upb_status *s) {
+  upb_alloc *alloc = upb_arena_alloc(&s->arena);
+  upb_oneofdef *o = upb_malloc(alloc, sizeof(upb_oneofdef));
+  upb_stringview name = google_protobuf_OneofDescriptorProto_name(oneof_proto);
+  upb_value o_ptr = upb_value_ptr(o);
 
-  add_defs = upb_gmalloc(sizeof(void*) * add_objs_size);
-  if (add_defs == NULL) goto oom_err;
-  upb_strtable_begin(&iter, &addtab);
-  for (add_n = 0; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-    add_defs[add_n++] = upb_value_getptr(upb_strtable_iter_value(&iter));
-  }
+  CHK(o);
+  CHK(upb_inttable_init2(&o->itof, UPB_CTYPE_PTR, alloc));
+  CHK(upb_strtable_init2(&o->ntof, UPB_CTYPE_PTR, alloc));
 
-  /* Validate defs. */
-  if (!_upb_def_validate(add_defs, add_n, status)) {
-    goto err;
+  o->index = upb_strtable_count(&m->ntof);
+  o->name = upb_strdup2(name.data, name.size, alloc);
+  o->parent = m;
+
+  CHK(upb_strtable_insert3(&m->ntof, name.data, name.size, o_ptr, alloc));
+
+  return true;
+}
+
+static bool create_field(
+    upb_symtab *s, const google_protobuf_FieldDescriptorProto *field_proto,
+    upb_msgdef *m, upb_status *s) {
+  upb_alloc *alloc = upb_arena_alloc(&s->arena);
+  upb_fielddef *f = upb_malloc(alloc, sizeof(upb_fielddef));
+  const google_protobuf_MessageOptions *options;
+  const upb_array *arr;
+
+  CHK(f);
+
+  f->msgdef = m;
+
+  union {
+    int64_t sint;
+    uint64_t uint;
+    double dbl;
+    float flt;
+    void *bytes;
+  } defaultval;
+  const upb_msgdef *msgdef;
+  union {
+    const upb_msgdef *msgdef;
+    const upb_msgdef *enumdef;
+  } sub;
+  const upb_oneofdef *oneof;
+  bool is_extension_;
+  bool lazy_;
+  bool packed_;
+  upb_intfmt_t intfmt;
+  bool tagdelim;
+  upb_fieldtype_t type_;
+  upb_label_t label_;
+  uint32_t number_;
+  uint32_t selector_base;  /* Used to index into a upb::Handlers table. */
+  uint32_t index_;
+}
+
+static bool create_msgdef(upb_symtab *s,
+                          const google_protobuf_DescriptorProto *msg_proto,
+                          upb_symtab *addtab, upb_status *status) {
+  upb_alloc *alloc = upb_arena_alloc(&s->arena);
+  upb_msgdef *m = upb_malloc(alloc, sizeof(upb_msgdef));
+  const google_protobuf_MessageOptions *options;
+  const upb_array *arr;
+
+  CHK(m);
+  CHK(upb_inttable_init2(&m->itof, UPB_CTYPE_PTR, alloc));
+  CHK(upb_strtable_init2(&m->ntof, UPB_CTYPE_PTR, alloc));
+
+  m->map_entry = false;
+
+  options = google_protobuf_DescriptorProto_options(msg_proto);
+
+  if (options) {
+    m->map_entry = google_protobuf_MessageOptions_map_entry(options);
   }
 
-  /* Cheat a little and give the array a new type.
-   * This is probably undefined behavior, but this code will be deleted soon. */
-  add_objs = (upb_refcounted**)add_defs;
+  arr = google_protobuf_DescriptorProto_oneof_decl(msg_proto);
 
-  freeze_n = add_n;
-  if (freeze_also) {
-    add_objs[freeze_n++] = freeze_also;
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_OneofDescriptorProto *oneof_proto =
+        (const void *)upb_array_get(arr, i);
+    CHK(create_oneofdef(s, oneof_proto, m, status));
   }
 
-  if (!upb_refcounted_freeze(add_objs, freeze_n, status,
-                             UPB_MAX_MESSAGE_DEPTH * 2)) {
-    goto err;
+  arr = google_protobuf_DescriptorProto_field(msg_proto);
+
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_FieldDescriptorProto *field_proto =
+        (const void *)upb_array_get(arr, i);
+    CHK(create_fielddef(s, field_proto, m, status));
   }
 
-  /* This must be delayed until all errors have been detected, since error
-   * recovery code uses this table to cleanup defs. */
-  upb_strtable_uninit(&addtab);
-
-  /* TODO(haberman) we don't properly handle errors after this point (like
-   * OOM in upb_strtable_insert() below). */
-  for (i = 0; i < add_n; i++) {
-    upb_def *def = (upb_def*)add_objs[i];
-    const char *name = upb_def_fullname(def);
-    bool success;
-    success = upb_strtable_insert(&s->symtab, name, upb_value_ptr(def));
-    UPB_ASSERT(success);
+  arr = google_protobuf_DescriptorProto_enum_type(msg_proto);
+
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_EnumDescriptorProto *enum_proto =
+        (const void *)upb_array_get(arr, i);
+    CHK(create_enumdef(s, enum_proto, addtab, status));
   }
-  upb_gfree(add_defs);
-  return true;
 
-oom_err:
-  upb_status_seterrmsg(status, "out of memory");
-err: {
-    /* We need to donate the refs back. */
-    upb_strtable_begin(&iter, &addtab);
-    for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-      upb_def *def = upb_value_getptr(upb_strtable_iter_value(&iter));
-      upb_def_donateref(def, s, ref_donor);
-    }
+  arr = google_protobuf_DescriptorProto_nested_type(msg_proto);
+
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_DescriptorProto *msg_proto2 =
+        (const void *)upb_array_get(arr, i);
+    CHK(create_msgdef(s, msg_proto2, addtab, status));
   }
-  upb_strtable_uninit(&addtab);
-  upb_gfree(add_defs);
-  UPB_ASSERT(!upb_ok(status));
-  return false;
+
+  return true;
 }
 
-bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
-                    void *ref_donor, upb_status *status) {
-  return symtab_add(s, defs, n, ref_donor, NULL, status);
+static char* strviewdup(upb_symtab *symtab, upb_stringview view) {
+  if (view.size == 0) {
+    return NULL;
+  }
+  return upb_strdup2(view.data, view.size, upb_arena_alloc(&symtab->arena));
 }
 
-bool upb_symtab_addfile(upb_symtab *s, upb_filedef *file, upb_status *status) {
-  size_t n;
+bool upb_symtab_addfile(upb_symtab *s, const char *buf, size_t len,
+                        upb_status *status) {
+  upb_arena tmparena;
+  upb_strtable addtab;
+  upb_alloc *alloc = upb_arena_alloc(&s->arena);
+  upb_stringview serialized = upb_stringview_make(buf, len);
+  const google_protobuf_FileDescriptorProto *file_proto;
+  const google_protobuf_FileOptions *file_options_proto;
+  upb_filedef *file = upb_malloc(alloc, sizeof(*file));
+  const upb_array *arr;
+  upb_strtable_iter iter;
   size_t i;
-  upb_def **defs;
-  bool ret;
 
-  n = upb_filedef_defcount(file);
-  if (n == 0) {
-    return true;
-  }
-  defs = upb_gmalloc(sizeof(*defs) * n);
+  upb_arena_init(&tmparena);
+  upb_strtable_init2(&addtab, UPB_CTYPE_PTR, upb_arena_alloc(&tmparena));
+  file_proto =
+      google_protobuf_FileDescriptorProto_parsenew(serialized, &tmparena);
 
-  if (defs == NULL) {
-    upb_status_seterrmsg(status, "Out of memory");
-    return false;
-  }
 
-  for (i = 0; i < n; i++) {
-    defs[i] = upb_filedef_mutabledef(file, i);
+  if (!file_proto || !file) goto err;
+
+  file->name =
+      strviewdup(s, google_protobuf_FileDescriptorProto_name(file_proto));
+  file->package =
+      strviewdup(s, google_protobuf_FileDescriptorProto_package(file_proto));
+  file->phpprefix = NULL;
+  file->phpnamespace = NULL;
+
+  file_options_proto = google_protobuf_FileDescriptorProto_options(file_proto);
+  if (file_options_proto) {
+    file->phpprefix =
+        strviewdup(s, google_protobuf_FileOptions_php_class_prefix(file_proto));
+    file->phpnamespace =
+        strviewdup(s, google_protobuf_FileOptions_php_namespace(file_proto));
   }
 
-  ret = symtab_add(s, defs, n, NULL, upb_filedef_upcast_mutable(file), status);
+  arr = google_protobuf_FileDescriptorProto_message_type(file_proto);
 
-  upb_gfree(defs);
-  return ret;
-}
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_DescriptorProto *msg_proto =
+        (const void *)upb_array_get(arr, i);
+    if (!create_msgdef(s, msg_proto, &addtab, status)) goto err;
+  }
 
-/* Iteration. */
+  arr = google_protobuf_FileDescriptorProto_enum_type(file_proto);
 
-static void advance_to_matching(upb_symtab_iter *iter) {
-  if (iter->type == UPB_DEF_ANY)
-    return;
+  for (i = 0; i < upb_array_size(arr); i++) {
+    const google_protobuf_EnumDescriptorProto *enum_proto =
+        (const void *)upb_array_get(arr, i);
+    if (!create_enumdef(s, enum_proto, &addtab, status)) goto err;
+  }
 
-  while (!upb_strtable_done(&iter->iter) &&
-         iter->type != upb_symtab_iter_def(iter)->type) {
-    upb_strtable_next(&iter->iter);
+  /* Now that all names are in the table, resolve references. */
+  upb_strtable_begin(&iter, &addtab);
+  for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
   }
-}
 
-void upb_symtab_begin(upb_symtab_iter *iter, const upb_symtab *s,
-                      upb_deftype_t type) {
-  upb_strtable_begin(&iter->iter, &s->symtab);
-  iter->type = type;
-  advance_to_matching(iter);
-}
+  /* Success; add addtab to symtab. */
+  upb_strtable_begin(&iter, &addtab);
+  for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
+    const char *key = upb_strtable_iter_key(&iter);
+    size_t keylen = upb_strtable_iter_keylen(&iter);
+    upb_value value = upb_strtable_iter_value(&iter);
+    upb_strtable_insert3(&s->symtab, key, keylen, value, alloc);
+  }
 
-void upb_symtab_next(upb_symtab_iter *iter) {
-  upb_strtable_next(&iter->iter);
-  advance_to_matching(iter);
-}
+  return true;
 
-bool upb_symtab_done(const upb_symtab_iter *iter) {
-  return upb_strtable_done(&iter->iter);
+err:
+  upb_arena_uninit(&tmparena);
+  return false;
 }
 
-const upb_def *upb_symtab_iter_def(const upb_symtab_iter *iter) {
-  return upb_value_getptr(upb_strtable_iter_value(&iter->iter));
+bool upb_symtab_addset(upb_symtab *s, const char *buf, size_t len,
+                       upb_status *status) {
+  return true;
 }