diff --git a/tests/json/test.upbdefs.c b/tests/json/test.upbdefs.c
index d2700903ac..43dd66e9a9 100644
--- a/tests/json/test.upbdefs.c
+++ b/tests/json/test.upbdefs.c
@@ -6,8 +6,6 @@
  * Do not edit -- your changes will be discarded when the file is
  * regenerated. */
 
-#include <assert.h>
-
 #include "upb/def.h"
 #include "upb/structdefs.int.h"
 
diff --git a/tests/json/test.upbdefs.h b/tests/json/test.upbdefs.h
index d3c23b38a0..8476060399 100644
--- a/tests/json/test.upbdefs.h
+++ b/tests/json/test.upbdefs.h
@@ -73,43 +73,43 @@ UPB_INLINE bool upbdefs_upb_test_json_MyEnum_is(const upb_enumdef *e) {
 
 
 /* Functions to get a fielddef from a msgdef reference. */
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_SubMessage_f_foo(const upb_msgdef *m) { assert(upbdefs_upb_test_json_SubMessage_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringStringEntry_f_key(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringStringEntry_f_value(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_bool_string(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 22); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_int32_string(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 21); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_bool(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 24); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_int32(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 23); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_msg(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 25); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_string(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 20); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_bool(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_bytes(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_enum(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_int32(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_int64(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_msg(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_string(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_uint32(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_uint64(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_bool(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 17); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_bytes(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 16); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_enum(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 19); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_int32(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 11); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_int64(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 12); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_msg(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 18); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_string(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 15); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_uint32(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 13); }
-UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_uint64(const upb_msgdef *m) { assert(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 14); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_SubMessage_f_foo(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_SubMessage_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringStringEntry_f_key(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_MapStringStringEntry_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_bool_string(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 22); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_int32_string(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 21); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_bool(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 24); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_int32(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 23); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_msg(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 25); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_map_string_string(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 20); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_bool(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_bytes(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_enum(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_int32(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_int64(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_msg(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_string(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_uint32(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_optional_uint64(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_bool(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 17); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_bytes(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 16); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_enum(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 19); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_int32(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 11); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_int64(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 12); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_msg(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 18); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_string(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 15); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_uint32(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 13); }
+UPB_INLINE const upb_fielddef *upbdefs_upb_test_json_TestMessage_f_repeated_uint64(const upb_msgdef *m) { UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m)); return upb_msgdef_itof(m, 14); }
 
 UPB_END_EXTERN_C
 
@@ -124,7 +124,7 @@ class MyEnum : public ::upb::reffed_ptr<const ::upb::EnumDef> {
  public:
   MyEnum(const ::upb::EnumDef* e, const void *ref_donor = NULL)
       : reffed_ptr(e, ref_donor) {
-    assert(upbdefs_upb_test_json_MyEnum_is(e));
+    UPB_ASSERT(upbdefs_upb_test_json_MyEnum_is(e));
   }
   static MyEnum get() {
     const ::upb::EnumDef* e = upbdefs_upb_test_json_MyEnum_get(&e);
@@ -136,7 +136,7 @@ class SubMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   SubMessage(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_upb_test_json_SubMessage_is(m));
+    UPB_ASSERT(upbdefs_upb_test_json_SubMessage_is(m));
   }
 
   static SubMessage get() {
@@ -149,7 +149,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   TestMessage(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_upb_test_json_TestMessage_is(m));
+    UPB_ASSERT(upbdefs_upb_test_json_TestMessage_is(m));
   }
 
   static TestMessage get() {
@@ -161,7 +161,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapBoolStringEntry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapBoolStringEntry_is(m));
     }
 
     static MapBoolStringEntry get() {
@@ -174,7 +174,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapInt32StringEntry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapInt32StringEntry_is(m));
     }
 
     static MapInt32StringEntry get() {
@@ -187,7 +187,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapStringBoolEntry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringBoolEntry_is(m));
     }
 
     static MapStringBoolEntry get() {
@@ -200,7 +200,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapStringInt32Entry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringInt32Entry_is(m));
     }
 
     static MapStringInt32Entry get() {
@@ -213,7 +213,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapStringMsgEntry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringMsgEntry_is(m));
     }
 
     static MapStringMsgEntry get() {
@@ -226,7 +226,7 @@ class TestMessage : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     MapStringStringEntry(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m));
+      UPB_ASSERT(upbdefs_upb_test_json_TestMessage_MapStringStringEntry_is(m));
     }
 
     static MapStringStringEntry get() {
diff --git a/tests/pb/test_decoder.cc b/tests/pb/test_decoder.cc
index a01e9999ed..702366a91d 100644
--- a/tests/pb/test_decoder.cc
+++ b/tests/pb/test_decoder.cc
@@ -116,11 +116,11 @@ void vappendf(string* str, const char *format, va_list args) {
   int count = vsnprintf(NULL, 0, format, args);
   if (count >= 0)
   {
-    assert(count < 32768);
+    UPB_ASSERT(count < 32768);
     char *buffer = new char[count + 1];
-    assert(buffer);
+    UPB_ASSERT(buffer);
     count = vsnprintf(buffer, count + 1, format, copy);
-    assert(count >= 0);
+    UPB_ASSERT(count >= 0);
     str->append(buffer, count);
     delete [] buffer;
   }
diff --git a/tests/test_util.h b/tests/test_util.h
index 5d165de038..f616c3603f 100644
--- a/tests/test_util.h
+++ b/tests/test_util.h
@@ -123,7 +123,7 @@ class VerboseParserEnvironment {
       skipped_with_null_ = true;
     } else {
       buf2 = (char*)malloc(bytes);
-      assert(buf2);
+      UPB_ASSERT(buf2);
       memcpy(buf2, buf_ + ofs_, bytes);
     }
 
diff --git a/tools/dump_cinit.lua b/tools/dump_cinit.lua
index e01e150ac9..6135b03a94 100644
--- a/tools/dump_cinit.lua
+++ b/tools/dump_cinit.lua
@@ -407,7 +407,6 @@ local function dump_defs_c(filedef, append)
 
   -- Emit forward declarations.
   emit_file_warning(filedef, append)
-  append('#include <assert.h>\n\n')
   append('#include "upb/def.h"\n')
   append('#include "upb/structdefs.int.h"\n\n')
   append("static const upb_msgdef %s;\n", linktab:cdecl(upb.DEF_MSG))
@@ -639,7 +638,7 @@ local function print_message(def, map, indent, append)
   append("%s  %s(const ::upb::MessageDef* m, const void *ref_donor = NULL)\n",
          indent, def:name())
   append("%s      : reffed_ptr(m, ref_donor) {\n", indent)
-  append("%s    assert(upbdefs_%s_is(m));\n", indent, to_cident(def:full_name()))
+  append("%s    UPB_ASSERT(upbdefs_%s_is(m));\n", indent, to_cident(def:full_name()))
   append("%s  }\n", indent)
   append("\n")
   append("%s  static %s get() {\n", indent, def:name())
@@ -659,7 +658,7 @@ local function print_enum(def, indent, append)
   append("%s  %s(const ::upb::EnumDef* e, const void *ref_donor = NULL)\n",
          indent, def:name())
   append("%s      : reffed_ptr(e, ref_donor) {\n", indent)
-  append("%s    assert(upbdefs_%s_is(e));\n", indent, to_cident(def:full_name()))
+  append("%s    UPB_ASSERT(upbdefs_%s_is(e));\n", indent, to_cident(def:full_name()))
   append("%s  }\n", indent)
   append("%s  static %s get() {\n", indent, def:name())
   append("%s    const ::upb::EnumDef* e = upbdefs_%s_get(&e);\n", indent, to_cident(def:full_name()))
@@ -748,7 +747,7 @@ local function dump_defs_h(file, append, linktab)
     local msg_cident = to_cident(f:containing_type():full_name())
     local field_cident = to_cident(f:name())
     append("UPB_INLINE const upb_fielddef *upbdefs_%s_f_%s(const upb_msgdef *m) {" ..
-           " assert(upbdefs_%s_is(m));" ..
+           " UPB_ASSERT(upbdefs_%s_is(m));" ..
            " return upb_msgdef_itof(m, %d); }\n",
            msg_cident, field_cident, msg_cident, f:number())
   end
diff --git a/upb/bindings/googlepb/bridge.cc b/upb/bindings/googlepb/bridge.cc
index c1961407d5..adba3e7c7f 100644
--- a/upb/bindings/googlepb/bridge.cc
+++ b/upb/bindings/googlepb/bridge.cc
@@ -18,7 +18,7 @@
 #define ASSERT_STATUS(status) do { \
   if (!upb_ok(status)) { \
     fprintf(stderr, "upb status failure: %s\n", upb_status_errmsg(status)); \
-    assert(upb_ok(status)); \
+    UPB_ASSERT(upb_ok(status)); \
   } \
   } while (0)
 
@@ -49,7 +49,7 @@ const goog::Message* TryGetFieldPrototype(const goog::Message& m,
 const goog::Message* GetFieldPrototype(const goog::Message& m,
                                        const goog::FieldDescriptor* f) {
   const goog::Message* ret = TryGetFieldPrototype(m, f);
-  assert(ret);
+  UPB_ASSERT(ret);
   return ret;
 }
 
@@ -66,7 +66,7 @@ const EnumDef* DefBuilder::GetEnumDef(const goog::EnumDescriptor* ed) {
   for (int i = 0; i < ed->value_count(); i++) {
     const goog::EnumValueDescriptor* val = ed->value(i);
     bool success = e->AddValue(val->name(), val->number(), &status);
-    UPB_ASSERT_VAR(success, success);
+    UPB_ASSERT(success);
   }
 
   e->Freeze(&status);
@@ -96,7 +96,7 @@ const MessageDef* DefBuilder::GetMaybeUnfrozenMessageDef(
 
   for (size_t i = 0; i < fields.size(); i++) {
     const goog::FieldDescriptor* proto2_f = fields[i];
-    assert(proto2_f);
+    UPB_ASSERT(proto2_f);
     md->AddField(NewFieldDef(proto2_f, m), &status);
   }
   ASSERT_STATUS(&status);
@@ -128,7 +128,7 @@ reffed_ptr<FieldDef> DefBuilder::NewFieldDef(const goog::FieldDescriptor* f,
     subm = TryGetFieldPrototype(*m, f);
 
     if (upb_f->type() == UPB_TYPE_MESSAGE) {
-      assert(subm);
+      UPB_ASSERT(subm);
     } else if (subm) {
       // Weak field: subm will be weak prototype even though the proto2
       // descriptor does not indicate a submessage field.
@@ -250,14 +250,14 @@ const Handlers* CodeCache::GetMaybeUnfrozenWriteHandlers(
     if (!proto2_f) {
       proto2_f = d->file()->pool()->FindExtensionByNumber(d, upb_f->number());
     }
-    assert(proto2_f);
+    UPB_ASSERT(proto2_f);
 
     bool ok = WriteHandlers::AddFieldHandler(m, proto2_f, h);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
 
     if (upb_f->type() == UPB_TYPE_MESSAGE) {
       const goog::Message* prototype = GetFieldPrototype(m, proto2_f);
-      assert(prototype);
+      UPB_ASSERT(prototype);
       const upb::Handlers* sub_handlers =
           GetMaybeUnfrozenWriteHandlers(upb_f->message_subdef(), *prototype);
       h->SetSubHandlers(upb_f, sub_handlers);
diff --git a/upb/bindings/googlepb/bridge.h b/upb/bindings/googlepb/bridge.h
index ec8ac410ba..ce55dc6b34 100644
--- a/upb/bindings/googlepb/bridge.h
+++ b/upb/bindings/googlepb/bridge.h
@@ -128,7 +128,7 @@ class DefBuilder {
 
   template <class T>
   T* AddToCache(const void *proto2_descriptor, reffed_ptr<T> def) {
-    assert(def_cache_.find(proto2_descriptor) == def_cache_.end());
+    UPB_ASSERT(def_cache_.find(proto2_descriptor) == def_cache_.end());
     def_cache_[proto2_descriptor] = def;
     return def.get();  // Continued lifetime is guaranteed by cache.
   }
@@ -207,7 +207,7 @@ class CodeCache {
       const MessageDef* md, const ::google::protobuf::Message& m);
 
   Handlers* AddToCache(const MessageDef* md, reffed_ptr<Handlers> handlers) {
-    assert(handlers_cache_.find(md) == handlers_cache_.end());
+    UPB_ASSERT(handlers_cache_.find(md) == handlers_cache_.end());
     handlers_cache_[md] = handlers;
     return handlers.get();  // Continue lifetime is guaranteed by the cache.
   }
diff --git a/upb/bindings/googlepb/proto1.cc b/upb/bindings/googlepb/proto1.cc
index fa51f79e80..c85bfca49b 100644
--- a/upb/bindings/googlepb/proto1.cc
+++ b/upb/bindings/googlepb/proto1.cc
@@ -35,7 +35,7 @@ namespace proto2 { class Arena; }
 #include "upb/sink.h"
 
 // Unconditionally evaluate, but also assert in debug mode.
-#define CHKRET(x) do { bool ok = (x); UPB_UNUSED(ok); assert(ok); } while (0)
+#define CHKRET(x) do { bool ok = (x); UPB_ASSERT(ok); } while (0)
 
 template <class T> static T* GetPointer(void* message, size_t offset) {
   return reinterpret_cast<T*>(static_cast<char*>(message) + offset);
@@ -58,7 +58,7 @@ class P2R_Handlers {
         dynamic_cast<const _pi::Proto2Reflection*>(base_r);
     if (!r) return false;
     // Extensions don't exist in proto1.
-    assert(!proto2_f->is_extension());
+    UPB_ASSERT(!proto2_f->is_extension());
 
 #define PRIMITIVE(name, type_name)                                             \
   case _pi::CREP_REQUIRED_##name:                                              \
@@ -107,7 +107,7 @@ class P2R_Handlers {
         SetWeakMessageHandlers(proto2_f, m, r, upb_f, h);
         return true;
       default:
-        assert(false);
+        UPB_ASSERT(false);
         return false;
     }
   }
@@ -147,10 +147,10 @@ class P2R_Handlers {
     } else if (dynamic_cast<const _pi::Proto2Reflection*>(m.GetReflection())) {
       // Since proto1 has no dynamic message, it must be from the generated
       // factory.
-      assert(f->cpp_type() == proto2::FieldDescriptor::CPPTYPE_MESSAGE);
+      UPB_ASSERT(f->cpp_type() == proto2::FieldDescriptor::CPPTYPE_MESSAGE);
       ret = proto2::MessageFactory::generated_factory()->GetPrototype(
                 f->message_type());
-      assert(ret);
+      UPB_ASSERT(ret);
       return ret;
     } else {
       return NULL;
@@ -175,7 +175,7 @@ class P2R_Handlers {
     }
 
     void SetHasbit(void* message) const {
-      assert(!is_repeated_);
+      UPB_ASSERT(!is_repeated_);
       uint8_t* byte = GetPointer<uint8_t>(message, hasbyte_);
       *byte |= mask_;
     }
@@ -193,13 +193,13 @@ class P2R_Handlers {
                                     upb::Handlers::Type type) {
     upb::Handlers::Selector selector;
     bool ok = upb::Handlers::GetSelector(f, type, &selector);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
     return selector;
   }
 
   static int16_t GetHasbit(const proto2::FieldDescriptor* f,
                            const _pi::Proto2Reflection* r) {
-    assert(!f->is_repeated());
+    UPB_ASSERT(!f->is_repeated());
     return (r->layout_->has_bit_offset * 8) + r->GetFieldLayout(f)->has_index;
   }
 
@@ -303,7 +303,7 @@ class P2R_Handlers {
       const proto2::FieldDescriptor* proto2_f, const _pi::Proto2Reflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
     // This type is only used for non-repeated string fields.
-    assert(!f->IsSequence());
+    UPB_ASSERT(!f->IsSequence());
     CHKRET(h->SetStartStringHandler(
         f, UpbBind(StartOutOfLineString, new FieldOffset(proto2_f, r))));
     CHKRET(h->SetStringHandler(f, UpbMakeHandler(OnStringBuf)));
@@ -452,7 +452,7 @@ class P2R_Handlers {
     // around waiting for reuse, which we will not do.
     static void Delete(Type* t) {
       UPB_UNUSED(t);
-      assert(false);
+      UPB_ASSERT(false);
     }
 #else
     static ::proto2::Arena* GetArena(Type* t) {
@@ -470,7 +470,7 @@ class P2R_Handlers {
     static void Delete(Type* t, ::proto2::Arena* arena) {
       UPB_UNUSED(t);
       UPB_UNUSED(arena);
-      assert(false);
+      UPB_ASSERT(false);
     }
     static void Merge(const Type& from, Type* to) {
       to->MergeFrom(from);
diff --git a/upb/bindings/googlepb/proto2.cc b/upb/bindings/googlepb/proto2.cc
index ee31d34838..bfd5ba2f42 100644
--- a/upb/bindings/googlepb/proto2.cc
+++ b/upb/bindings/googlepb/proto2.cc
@@ -21,14 +21,14 @@
 namespace {
 
 template<typename To, typename From> To CheckDownCast(From* f) {
-  assert(f == NULL || dynamic_cast<To>(f) != NULL);
+  UPB_ASSERT(f == NULL || dynamic_cast<To>(f) != NULL);
   return static_cast<To>(f);
 }
 
 }
 
 // Unconditionally evaluate, but also assert in debug mode.
-#define CHKRET(x) do { bool ok = (x); UPB_UNUSED(ok); assert(ok); } while (0)
+#define CHKRET(x) do { bool ok = (x); UPB_ASSERT(ok); } while (0)
 
 namespace upb {
 namespace google_google3 { class GMR_Handlers; }
@@ -222,7 +222,7 @@ case goog::FieldDescriptor::cpptype:                                           \
                                     upb::Handlers::Type type) {
     upb::Handlers::Selector selector;
     bool ok = upb::Handlers::GetSelector(f, type, &selector);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
     return selector;
   }
 
@@ -230,7 +230,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const goog::FieldDescriptor* f,
       const goog::internal::GeneratedMessageReflection* r) {
     // proto2 does not store hasbits for repeated fields.
-    assert(!f->is_repeated());
+    UPB_ASSERT(!f->is_repeated());
     return (r->has_bits_offset_ * 8) + f->index();
   }
 
@@ -238,7 +238,7 @@ case goog::FieldDescriptor::cpptype:                                           \
   static size_t GetOneofDiscriminantOffset(
       const goog::FieldDescriptor* f,
       const goog::internal::GeneratedMessageReflection* r) {
-    assert(f->containing_oneof());
+    UPB_ASSERT(f->containing_oneof());
     return r->oneof_case_offset_ + f->containing_oneof()->index();
   }
 #endif
@@ -326,7 +326,7 @@ case goog::FieldDescriptor::cpptype:                                           \
     }
 
     void SetHasbit(void* m) const {
-      assert(!is_repeated_);
+      UPB_ASSERT(!is_repeated_);
       uint8_t* byte = GetPointer<uint8_t>(m, hasbyte_);
       *byte |= mask_;
     }
@@ -470,7 +470,7 @@ case goog::FieldDescriptor::cpptype:                                           \
           return ONEOF_TYPE_STRINGPIECE;
 #endif
         default:
-          assert(false);
+          UPB_ASSERT(false);
           return ONEOF_TYPE_NONE;
       }
     }
@@ -582,7 +582,7 @@ case goog::FieldDescriptor::cpptype:                                           \
     }
 #ifdef GOOGLE_PROTOBUF_HAS_ONEOF
       else if (proto2_f->containing_oneof()) {
-      assert(!proto2_f->is_repeated());
+      UPB_ASSERT(!proto2_f->is_repeated());
       CHKRET(h->SetValueHandler<T>(
           f, UpbBindT(SetOneofPrimitive<T>,
                       new OneofFieldHandlerData(proto2_f, r))));
@@ -656,7 +656,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const goog::FieldDescriptor* proto2_f,
       const goog::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(!proto2_f->is_extension());
+    UPB_ASSERT(!proto2_f->is_extension());
     scoped_ptr<EnumHandlerData> data(new EnumHandlerData(proto2_f, r, f));
     if (f->IsSequence()) {
       CHKRET(h->SetInt32Handler(f, UpbBind(AppendEnum, data.release())));
@@ -696,7 +696,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const goog::FieldDescriptor* proto2_f,
       const goog::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(proto2_f->is_extension());
+    UPB_ASSERT(proto2_f->is_extension());
     scoped_ptr<ExtensionFieldData> data(new ExtensionFieldData(proto2_f, r));
     if (f->IsSequence()) {
       CHKRET(
@@ -745,11 +745,11 @@ case goog::FieldDescriptor::cpptype:                                           \
       const goog::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f,
       upb::Handlers* h) {
-    assert(!proto2_f->is_extension());
+    UPB_ASSERT(!proto2_f->is_extension());
     CHKRET(h->SetStringHandler(f, UpbMakeHandlerT(&OnStringBuf<T>)));
 #ifdef GOOGLE_PROTOBUF_HAS_ONEOF
     if (proto2_f->containing_oneof()) {
-      assert(!f->IsSequence());
+      UPB_ASSERT(!f->IsSequence());
       CHKRET(h->SetStartStringHandler(
           f, UpbBindT(&StartOneofString<T>,
                       new OneofFieldHandlerData(proto2_f, r))));
@@ -835,7 +835,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const goog::FieldDescriptor* proto2_f,
       const goog::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(proto2_f->is_extension());
+    UPB_ASSERT(proto2_f->is_extension());
     CHKRET(h->SetStringHandler(f, UpbMakeHandlerT(OnStringBuf<T>)));
     scoped_ptr<ExtensionFieldData> data(new ExtensionFieldData(proto2_f, r));
     if (f->IsSequence()) {
@@ -908,7 +908,7 @@ case goog::FieldDescriptor::cpptype:                                           \
         new SubMessageHandlerData(proto2_f, r, field_prototype));
 #ifdef GOOGLE_PROTOBUF_HAS_ONEOF
     if (proto2_f->containing_oneof()) {
-      assert(!f->IsSequence());
+      UPB_ASSERT(!f->IsSequence());
       CHKRET(h->SetStartSubMessageHandler(
           f, UpbBind(StartOneofSubMessage, new OneofSubMessageHandlerData(
                                                proto2_f, r, field_prototype))));
@@ -965,7 +965,7 @@ case goog::FieldDescriptor::cpptype:                                           \
     // around waiting for reuse, which we will not do.
     static void Delete(Type* t) {
       UPB_UNUSED(t);
-      assert(false);
+      UPB_ASSERT(false);
     }
 #endif  // ifdef GOOGLE_PROTOBUF_HAS_ARENAS
 
@@ -1089,7 +1089,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       // "We could speed this up by using CordReader internals."
       Cord piece(*source_cord);
       piece.RemovePrefix(handle->object_offset() + (buf - handle->buffer()));
-      assert(piece.size() >= n);
+      UPB_ASSERT(piece.size() >= n);
       piece.RemoveSuffix(piece.size() - n);
 
       c->Append(piece);
@@ -1102,7 +1102,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const proto2::FieldDescriptor* proto2_f,
       const proto2::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(!proto2_f->is_extension());
+    UPB_ASSERT(!proto2_f->is_extension());
     CHKRET(h->SetStringHandler(f, UpbMakeHandler(&OnCordBuf)));
     if (f->IsSequence()) {
       SetStartRepeatedField<Cord>(proto2_f, r, f, h);
@@ -1139,7 +1139,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const proto2::FieldDescriptor* proto2_f,
       const proto2::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(!proto2_f->is_extension());
+    UPB_ASSERT(!proto2_f->is_extension());
     CHKRET(h->SetStringHandler(f, UpbMakeHandler(OnStringPieceBuf)));
     if (f->IsSequence()) {
       SetStartRepeatedPtrField<proto2::internal::StringPieceField>(proto2_f, r,
@@ -1194,7 +1194,7 @@ case goog::FieldDescriptor::cpptype:                                           \
       const proto2::Message& m,
       const proto2::internal::GeneratedMessageReflection* r,
       const upb::FieldDef* f, upb::Handlers* h) {
-    assert(!proto2_f->is_repeated());
+    UPB_ASSERT(!proto2_f->is_repeated());
     const goog::Message* field_prototype = GetFieldPrototype(m, proto2_f);
     CHKRET(h->SetStringHandler(f, UpbMakeHandler(OnLazyFieldBuf)));
     if (proto2_f->is_extension()) {
diff --git a/upb/bindings/lua/upb.c b/upb/bindings/lua/upb.c
index 4768212d67..148367610b 100644
--- a/upb/bindings/lua/upb.c
+++ b/upb/bindings/lua/upb.c
@@ -141,7 +141,7 @@ static void *newudata_with_userval(lua_State *L, size_t size,
 
   /* Set metatable. */
   luaL_getmetatable(L, type);
-  assert(!lua_isnil(L, -1));  /* Should have been created by luaopen_upb. */
+  UPB_ASSERT(!lua_isnil(L, -1));  /* Should have been created by luaopen_upb. */
   lua_setmetatable(L, -2);
 
   lua_newtable(L);
@@ -322,7 +322,7 @@ bool lupb_refcounted_pushwrapper(lua_State *L, const upb_refcounted *obj,
   /* Lookup our cache in the registry (we don't put our objects in the registry
    * directly because we need our cache to be a weak table). */
   lua_getfield(L, LUA_REGISTRYINDEX, LUPB_OBJCACHE);
-  assert(!lua_isnil(L, -1));  /* Should have been created by luaopen_upb. */
+  UPB_ASSERT(!lua_isnil(L, -1));  /* Should have been created by luaopen_upb. */
   lua_pushlightuserdata(L, (void*)obj);
   lua_rawget(L, -2);
   /* Stack is now: objcache, cached value. */
@@ -382,7 +382,7 @@ void lupb_refcounted_pushnewrapper(lua_State *L, const upb_refcounted *obj,
                                    const char *type, const void *ref_donor) {
   bool created =
       lupb_refcounted_pushwrapper(L, obj, type, ref_donor, sizeof(void *));
-  UPB_ASSERT_VAR(created, created == true);
+  UPB_ASSERT(created == true);
 }
 
 static int lupb_refcounted_gc(lua_State *L) {
@@ -461,7 +461,7 @@ bool lupb_def_pushwrapper(lua_State *L, const upb_def *def,
 void lupb_def_pushnewrapper(lua_State *L, const upb_def *def,
                             const void *ref_donor) {
   bool created = lupb_def_pushwrapper(L, def, ref_donor);
-  UPB_ASSERT_VAR(created, created == true);
+  UPB_ASSERT(created == true);
 }
 
 static int lupb_def_type(lua_State *L) {
@@ -1310,7 +1310,7 @@ static int lupb_filedefiter_next(lua_State *L) {
     const upb_def *def;
 
     def = upb_filedef_def(f, i);
-    assert(def);
+    UPB_ASSERT(def);
 
     if (type == UPB_DEF_ANY || upb_def_type(def) == type) {
       lua_pushinteger(L, i + 1);
@@ -1738,7 +1738,7 @@ static lupb_msgdef *lupb_msg_assignoffsets(lua_State *L, int narg) {
     upb_fielddef *f = upb_msg_iter_field(&i);
     if (upb_fielddef_type(f) == UPB_TYPE_MESSAGE) {
       bool created = lupb_def_pushwrapper(L, upb_fielddef_subdef(f), NULL);
-      UPB_ASSERT_VAR(created, !created);
+      UPB_ASSERT(!created);
       lupb_msg_assignoffsets(L, -1);
       lua_rawseti(L, -2, idx++);  /* Append to uservalue. */
     }
diff --git a/upb/bindings/python/upb.c b/upb/bindings/python/upb.c
index 778b821955..1646accb7a 100644
--- a/upb/bindings/python/upb.c
+++ b/upb/bindings/python/upb.c
@@ -63,7 +63,7 @@ static PyObject *weakref_callback = NULL;
 
 static PyObject *PyUpb_StringForPointer(const void *ptr) {
   PyObject *o = PyString_FromStringAndSize((const char *)&ptr, sizeof(void*));
-  assert(o);
+  UPB_ASSERT(o);
   return o;
 }
 
@@ -73,11 +73,11 @@ static PyObject *PyUpb_ObjCacheDeleteCallback(PyObject *self, PyObject *ref) {
   // remove from the cache.  As a result we are forced to keep a second map
   // mapping weakref->C pointer.
   PyObject *ptr_str = PyDict_GetItem(reverse_cache, ref);
-  assert(ptr_str);
+  UPB_ASSERT(ptr_str);
   int err = PyDict_DelItem(obj_cache, ptr_str);
-  assert(!err);
+  UPB_ASSERT(!err);
   err = PyDict_DelItem(reverse_cache, ref);
-  assert(!err);
+  UPB_ASSERT(!err);
   return Py_None;
 }
 
@@ -87,7 +87,7 @@ static PyObject *PyUpb_ObjCacheGet(const void *obj, PyTypeObject *type) {
   PyObject *ret;
   if (ref) {
     ret = PyWeakref_GetObject(ref);
-    assert(ret != Py_None);
+    UPB_ASSERT(ret != Py_None);
     Py_INCREF(ret);
   } else {
     PyUpb_ObjWrapper *wrapper = (PyUpb_ObjWrapper*)type->tp_alloc(type, 0);
@@ -95,12 +95,12 @@ static PyObject *PyUpb_ObjCacheGet(const void *obj, PyTypeObject *type) {
     wrapper->weakreflist = NULL;
     ret = (PyObject*)wrapper;
     ref = PyWeakref_NewRef(ret, weakref_callback);
-    assert(PyWeakref_GetObject(ref) == ret);
-    assert(ref);
+    UPB_ASSERT(PyWeakref_GetObject(ref) == ret);
+    UPB_ASSERT(ref);
     PyDict_SetItem(obj_cache, kv, ref);
     PyDict_SetItem(reverse_cache, ref, kv);
   }
-  assert(ret);
+  UPB_ASSERT(ret);
   Py_DECREF(kv);
   return ret;
 }
diff --git a/upb/bindings/ruby/upb.c b/upb/bindings/ruby/upb.c
index ea0fcc8a3a..7598bac4c6 100644
--- a/upb/bindings/ruby/upb.c
+++ b/upb/bindings/ruby/upb.c
@@ -161,8 +161,8 @@ static void objcache_init() {
 
 // Call to uninitialize the cache.  Should be done once on process shutdown.
 static void objcache_uninit(ruby_vm_t *vm) {
-  assert(objcache_initialized);
-  assert(upb_inttable_count(&objcache) == 0);
+  UPB_ASSERT(objcache_initialized);
+  UPB_ASSERT(upb_inttable_count(&objcache) == 0);
 
   objcache_initialized = false;
   upb_inttable_uninit(&objcache);
@@ -171,7 +171,7 @@ static void objcache_uninit(ruby_vm_t *vm) {
 // Looks up the given object in the cache.  If the corresponding Ruby wrapper
 // object is found, returns it, otherwise creates the wrapper and returns that.
 static VALUE objcache_getorcreate(const void *obj, createfunc *func) {
-  assert(objcache_initialized);
+  UPB_ASSERT(objcache_initialized);
 
   upb_value v;
   if (!upb_inttable_lookupptr(&objcache, obj, &v)) {
@@ -184,10 +184,10 @@ static VALUE objcache_getorcreate(const void *obj, createfunc *func) {
 // Removes the given object from the cache.  Should only be called by the code
 // that is freeing the wrapper object.
 static void objcache_remove(const void *obj) {
-  assert(objcache_initialized);
+  UPB_ASSERT(objcache_initialized);
 
   bool removed = upb_inttable_removeptr(&objcache, obj, NULL);
-  UPB_ASSERT_VAR(removed, removed);
+  UPB_ASSERT(removed);
 }
 
 /* message layout *************************************************************/
@@ -256,7 +256,7 @@ static size_t rupb_sizeof(const upb_fielddef *f) {
     default:
       break;
   }
-  assert(false);
+  UPB_ASSERT(false);
   return 0;
 }
 
@@ -656,7 +656,7 @@ static VALUE msg_accessor(int argc, VALUE *argv, VALUE obj) {
   rupb_Message *msg = msg_get(obj);
 
   // method_missing protocol: (method [, arg1, arg2, ...])
-  assert(argc >= 1 && SYMBOL_P(argv[0]));
+  UPB_ASSERT(argc >= 1 && SYMBOL_P(argv[0]));
   // OPT(haberman): find a better way to get the method name.
   // This is allocating a new string each time, which should not be necessary.
   VALUE method = rb_id2str(SYM2ID(argv[0]));
@@ -668,7 +668,7 @@ static VALUE msg_accessor(int argc, VALUE *argv, VALUE obj) {
     //   foo.bar = x
     //
     // Ruby should guarantee that we have exactly one more argument (x)
-    assert(argc == 2);
+    UPB_ASSERT(argc == 2);
     return msg_setter(msg, method, argv[1]);
   } else {
     // Call was:
@@ -1011,14 +1011,14 @@ static const upb_handlers *new_fill_handlers(const rupb_MessageDef *rmd,
 static upb_selector_t getsel(const upb_fielddef *f, upb_handlertype_t type) {
   upb_selector_t ret;
   bool ok = upb_handlers_getselector(f, type, &ret);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return ret;
 }
 
 static void putstr(VALUE str, const upb_fielddef *f, upb_sink *sink) {
   if (str == Qnil) return;
 
-  assert(BUILTIN_TYPE(str) == RUBY_T_STRING);
+  UPB_ASSERT(BUILTIN_TYPE(str) == RUBY_T_STRING);
   upb_sink subsink;
 
   upb_sink_startstr(sink, getsel(f, UPB_HANDLER_STARTSTR), RSTRING_LEN(str),
@@ -1042,7 +1042,7 @@ static void putsubmsg(VALUE submsg, const upb_fielddef *f, upb_sink *sink) {
 static void putary(VALUE ary, const upb_fielddef *f, upb_sink *sink) {
   if (ary == Qnil) return;
 
-  assert(BUILTIN_TYPE(ary) == RUBY_T_ARRAY);
+  UPB_ASSERT(BUILTIN_TYPE(ary) == RUBY_T_ARRAY);
   upb_sink subsink;
 
   upb_sink_startseq(sink, getsel(f, UPB_HANDLER_STARTSEQ), &subsink);
diff --git a/upb/bindings/stdc/io.c b/upb/bindings/stdc/io.c
index a95eb488ab..fe82014a45 100644
--- a/upb/bindings/stdc/io.c
+++ b/upb/bindings/stdc/io.c
@@ -36,7 +36,7 @@ static upb_stdio_buf *upb_stdio_rotatebufs(upb_stdio *s) {
       reuse[num_reused++] = buf;
     }
   }
-  assert(num_reused + num_inuse == s->nbuf);
+  UPB_ASSERT(num_reused + num_inuse == s->nbuf);
   memcpy(s->bufs + num_inuse, reuse, num_reused * sizeof(upb_stdio_buf*));
   if (num_reused == 0) {
     ++s->nbuf;
@@ -78,7 +78,7 @@ retry:
       return upb_errno_is_wouldblock(errno) ?
           UPB_BYTE_WOULDBLOCK : UPB_BYTE_ERROR;
     }
-    assert(false);
+    UPB_ASSERT(false);
   }
   return UPB_BYTE_OK;
 }
diff --git a/upb/def.c b/upb/def.c
index 621eefc85f..c47f02069e 100644
--- a/upb/def.c
+++ b/upb/def.c
@@ -104,7 +104,7 @@ const char *upb_def_name(const upb_def *d) {
 }
 
 bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s) {
-  assert(!upb_def_isfrozen(def));
+  UPB_ASSERT(!upb_def_isfrozen(def));
   if (!upb_isident(fullname, strlen(fullname), true, s)) {
     return false;
   }
@@ -133,7 +133,7 @@ upb_def *upb_def_dup(const upb_def *def, const void *o) {
     case UPB_DEF_ENUM:
       return upb_enumdef_upcast_mutable(
           upb_enumdef_dup(upb_downcast_enumdef(def), o));
-    default: assert(false); return NULL;
+    default: UPB_ASSERT(false); return NULL;
   }
 }
 
@@ -204,14 +204,14 @@ static bool upb_validate_field(upb_fielddef *f, upb_status *s) {
     bool has_default_number = upb_fielddef_enumhasdefaultint32(f);
 
     /* Previously verified by upb_validate_enumdef(). */
-    assert(upb_enumdef_numvals(upb_fielddef_enumsubdef(f)) > 0);
+    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). */
-    assert(has_default_name || has_default_number);
+    UPB_ASSERT(has_default_name || has_default_number);
 
     if (!has_default_name) {
       upb_status_seterrf(s,
@@ -267,7 +267,7 @@ static bool upb_validate_enumdef(const upb_enumdef *e, upb_status *s) {
 uint32_t field_rank(const upb_fielddef *f) {
   uint32_t ret = upb_fielddef_number(f);
   const uint32_t high_bit = 1 << 30;
-  assert(ret < high_bit);
+  UPB_ASSERT(ret < high_bit);
   if (!upb_fielddef_issubmsg(f))
     ret |= high_bit;
   return ret;
@@ -305,7 +305,7 @@ 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);
-    assert(f->msg.def == m);
+    UPB_ASSERT(f->msg.def == m);
     if (!upb_validate_field(f, s)) {
       upb_gfree(fields);
       return false;
@@ -418,7 +418,7 @@ err:
     upb_def *def = defs[i];
     def->came_from_user = false;
   }
-  assert(!(s && upb_ok(s)));
+  UPB_ASSERT(!(s && upb_ok(s)));
   return false;
 }
 
@@ -537,19 +537,19 @@ bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
 
   if (upb_enumdef_numvals(e) == 1) {
     bool ok = upb_enumdef_setdefault(e, num, NULL);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
   }
 
   return true;
 }
 
 int32_t upb_enumdef_default(const upb_enumdef *e) {
-  assert(upb_enumdef_iton(e, e->defaultval));
+  UPB_ASSERT(upb_enumdef_iton(e, e->defaultval));
   return e->defaultval;
 }
 
 bool upb_enumdef_setdefault(upb_enumdef *e, int32_t val, upb_status *s) {
-  assert(!upb_enumdef_isfrozen(e));
+  UPB_ASSERT(!upb_enumdef_isfrozen(e));
   if (!upb_enumdef_iton(e, val)) {
     upb_status_seterrf(s, "number '%d' is not in the enum.", val);
     return false;
@@ -633,7 +633,7 @@ static void freefield(upb_refcounted *r) {
 
 static const char *enumdefaultstr(const upb_fielddef *f) {
   const upb_enumdef *e;
-  assert(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
+  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. */
@@ -650,7 +650,7 @@ static const char *enumdefaultstr(const upb_fielddef *f) {
       /* Default is completely unset; pull enumdef default. */
       if (upb_enumdef_numvals(e) > 0) {
         const char *name = upb_enumdef_iton(e, upb_enumdef_default(e));
-        assert(name);
+        UPB_ASSERT(name);
         return name;
       }
     }
@@ -660,7 +660,7 @@ static const char *enumdefaultstr(const upb_fielddef *f) {
 
 static bool enumdefaultint32(const upb_fielddef *f, int32_t *val) {
   const upb_enumdef *e;
-  assert(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
+  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. */
@@ -761,7 +761,7 @@ bool upb_fielddef_typeisset(const upb_fielddef *f) {
 }
 
 upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f) {
-  assert(f->type_is_set_);
+  UPB_ASSERT(f->type_is_set_);
   return f->type_;
 }
 
@@ -863,7 +863,7 @@ static void release_containingtype(upb_fielddef *f) {
 bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
                                         upb_status *s) {
   char *name_copy;
-  assert(!upb_fielddef_isfrozen(f));
+  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;
@@ -894,7 +894,7 @@ bool upb_fielddef_setname(upb_fielddef *f, const char *name, upb_status *s) {
 static void chkdefaulttype(const upb_fielddef *f, upb_fieldtype_t type) {
   UPB_UNUSED(f);
   UPB_UNUSED(type);
-  assert(f->type_is_set_ && upb_fielddef_type(f) == type);
+  UPB_ASSERT(f->type_is_set_ && upb_fielddef_type(f) == type);
 }
 
 int64_t upb_fielddef_defaultint64(const upb_fielddef *f) {
@@ -906,7 +906,7 @@ 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_VAR(ok, ok);
+    UPB_ASSERT(ok);
     return val;
   } else {
     chkdefaulttype(f, UPB_TYPE_INT32);
@@ -940,14 +940,14 @@ double upb_fielddef_defaultdouble(const upb_fielddef *f) {
 }
 
 const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len) {
-  assert(f->type_is_set_);
-  assert(upb_fielddef_type(f) == UPB_TYPE_STRING ||
+  UPB_ASSERT(f->type_is_set_);
+  UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_STRING ||
          upb_fielddef_type(f) == UPB_TYPE_BYTES ||
          upb_fielddef_type(f) == UPB_TYPE_ENUM);
 
   if (upb_fielddef_type(f) == UPB_TYPE_ENUM) {
     const char *ret = enumdefaultstr(f);
-    assert(ret);
+    UPB_ASSERT(ret);
     /* Enum defaults can't have embedded NULLs. */
     if (len) *len = strlen(ret);
     return ret;
@@ -1029,8 +1029,8 @@ bool upb_fielddef_setnumber(upb_fielddef *f, uint32_t number, upb_status *s) {
 }
 
 void upb_fielddef_settype(upb_fielddef *f, upb_fieldtype_t type) {
-  assert(!upb_fielddef_isfrozen(f));
-  assert(upb_fielddef_checktype(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;
@@ -1038,7 +1038,7 @@ void upb_fielddef_settype(upb_fielddef *f, upb_fieldtype_t type) {
 }
 
 void upb_fielddef_setdescriptortype(upb_fielddef *f, int type) {
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   switch (type) {
     case UPB_DESCRIPTOR_TYPE_DOUBLE:
       upb_fielddef_settype(f, UPB_TYPE_DOUBLE);
@@ -1080,7 +1080,7 @@ void upb_fielddef_setdescriptortype(upb_fielddef *f, int type) {
     case UPB_DESCRIPTOR_TYPE_ENUM:
       upb_fielddef_settype(f, UPB_TYPE_ENUM);
       break;
-    default: assert(false);
+    default: UPB_ASSERT(false);
   }
 
   if (type == UPB_DESCRIPTOR_TYPE_FIXED64 ||
@@ -1138,34 +1138,34 @@ upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f) {
 }
 
 void upb_fielddef_setisextension(upb_fielddef *f, bool is_extension) {
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   f->is_extension_ = is_extension;
 }
 
 void upb_fielddef_setlazy(upb_fielddef *f, bool lazy) {
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   f->lazy_ = lazy;
 }
 
 void upb_fielddef_setpacked(upb_fielddef *f, bool packed) {
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   f->packed_ = packed;
 }
 
 void upb_fielddef_setlabel(upb_fielddef *f, upb_label_t label) {
-  assert(!upb_fielddef_isfrozen(f));
-  assert(upb_fielddef_checklabel(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) {
-  assert(!upb_fielddef_isfrozen(f));
-  assert(upb_fielddef_checkintfmt(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) {
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   f->tagdelim = tag_delim;
   f->tagdelim = tag_delim;
 }
@@ -1173,12 +1173,12 @@ void upb_fielddef_settagdelim(upb_fielddef *f, bool 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) {
-    assert(false);
+    UPB_ASSERT(false);
     return false;
   }
   if (f->default_is_string) {
     str_t *s = f->defaultval.bytes;
-    assert(s || type == UPB_TYPE_ENUM);
+    UPB_ASSERT(s || type == UPB_TYPE_ENUM);
     if (s) freestr(s);
   }
   f->default_is_string = false;
@@ -1226,16 +1226,16 @@ void upb_fielddef_setdefaultdouble(upb_fielddef *f, double value) {
 bool upb_fielddef_setdefaultstr(upb_fielddef *f, const void *str, size_t len,
                                 upb_status *s) {
   str_t *str2;
-  assert(upb_fielddef_isstring(f) || f->type_ == UPB_TYPE_ENUM);
+  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;
-    assert(s || f->type_ == UPB_TYPE_ENUM);
+    UPB_ASSERT(s || f->type_ == UPB_TYPE_ENUM);
     if (s) freestr(s);
   } else {
-    assert(f->type_ == UPB_TYPE_ENUM);
+    UPB_ASSERT(f->type_ == UPB_TYPE_ENUM);
   }
 
   str2 = newstr(str, len);
@@ -1246,18 +1246,18 @@ bool upb_fielddef_setdefaultstr(upb_fielddef *f, const void *str, size_t len,
 
 void upb_fielddef_setdefaultcstr(upb_fielddef *f, const char *str,
                                  upb_status *s) {
-  assert(f->type_is_set_);
+  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;
-  assert(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
+  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
   return enumdefaultint32(f, &val);
 }
 
 bool upb_fielddef_enumhasdefaultstr(const upb_fielddef *f) {
-  assert(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
+  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
   return enumdefaultstr(f) != NULL;
 }
 
@@ -1287,8 +1287,8 @@ static void release_subdef(upb_fielddef *f) {
 
 bool upb_fielddef_setsubdef(upb_fielddef *f, const upb_def *subdef,
                             upb_status *s) {
-  assert(!upb_fielddef_isfrozen(f));
-  assert(upb_fielddef_hassubdef(f));
+  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;
@@ -1310,7 +1310,7 @@ bool upb_fielddef_setenumsubdef(upb_fielddef *f, const upb_enumdef *subdef,
 bool upb_fielddef_setsubdefname(upb_fielddef *f, const char *name,
                                 upb_status *s) {
   char *name_copy;
-  assert(!upb_fielddef_isfrozen(f));
+  UPB_ASSERT(!upb_fielddef_isfrozen(f));
   if (!upb_fielddef_hassubdef(f)) {
     upb_status_seterrmsg(s, "field type does not accept a subdef");
     return false;
@@ -1443,7 +1443,7 @@ upb_msgdef *upb_msgdef_dup(const upb_msgdef *m, const void *owner) {
                            NULL);
   newm->map_entry = m->map_entry;
   newm->syntax = m->syntax;
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   for(upb_msg_field_begin(&i, m);
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {
@@ -1644,7 +1644,7 @@ bool upb_msgdef_lookupname(const upb_msgdef *m, const char *name, size_t len,
 
   *o = upb_trygetoneof(upb_value_getptr(val));
   *f = upb_trygetfield(upb_value_getptr(val));
-  assert((*o != NULL) ^ (*f != NULL));  /* Exactly one of the two should be set. */
+  UPB_ASSERT((*o != NULL) ^ (*f != NULL));  /* Exactly one of the two should be set. */
   return true;
 }
 
@@ -1659,7 +1659,7 @@ int upb_msgdef_numoneofs(const upb_msgdef *m) {
 }
 
 void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry) {
-  assert(!upb_msgdef_isfrozen(m));
+  UPB_ASSERT(!upb_msgdef_isfrozen(m));
   m->map_entry = map_entry;
 }
 
@@ -1772,7 +1772,7 @@ upb_oneofdef *upb_oneofdef_dup(const upb_oneofdef *o, const void *owner) {
   upb_oneofdef *newo = upb_oneofdef_new(owner);
   if (!newo) return NULL;
   ok = upb_oneofdef_setname(newo, upb_oneofdef_name(o), NULL);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   for (upb_oneof_begin(&i, o); !upb_oneof_done(&i); upb_oneof_next(&i)) {
     upb_fielddef *f = upb_fielddef_dup(upb_oneof_iter_field(&i), &f);
     if (!f || !upb_oneofdef_addfield(newo, f, &f, NULL)) {
@@ -1786,7 +1786,7 @@ upb_oneofdef *upb_oneofdef_dup(const upb_oneofdef *o, const void *owner) {
 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) {
-  assert(!upb_oneofdef_isfrozen(o));
+  UPB_ASSERT(!upb_oneofdef_isfrozen(o));
   if (upb_oneofdef_containingtype(o)) {
     upb_status_seterrmsg(s, "oneof already added to a message");
     return false;
@@ -1818,8 +1818,8 @@ int upb_oneofdef_numfields(const upb_oneofdef *o) {
 bool upb_oneofdef_addfield(upb_oneofdef *o, upb_fielddef *f,
                            const void *ref_donor,
                            upb_status *s) {
-  assert(!upb_oneofdef_isfrozen(o));
-  assert(!o->parent || !upb_msgdef_isfrozen(o->parent));
+  UPB_ASSERT(!upb_oneofdef_isfrozen(o));
+  UPB_ASSERT(!o->parent || !upb_msgdef_isfrozen(o->parent));
 
   /* This method is idempotent. Check if |f| is already part of this oneofdef
    * and return immediately if so. */
diff --git a/upb/def.h b/upb/def.h
index 2cfaebc52a..b4f23525a4 100644
--- a/upb/def.h
+++ b/upb/def.h
@@ -186,7 +186,7 @@ UPB_END_EXTERN_C
     return (upb_##lower *)def;                                             \
   }                                                                        \
   UPB_INLINE const upb_##lower *upb_downcast_##lower(const upb_def *def) { \
-    assert(upb_def_type(def) == UPB_DEF_##upper);                          \
+    UPB_ASSERT(upb_def_type(def) == UPB_DEF_##upper);                          \
     return (const upb_##lower *)def;                                       \
   }                                                                        \
   UPB_INLINE upb_##lower *upb_dyncast_##lower##_mutable(upb_def *def) {    \
@@ -1420,7 +1420,7 @@ UPB_END_EXTERN_C
 #ifdef __cplusplus
 
 UPB_INLINE const char* upb_safecstr(const std::string& str) {
-  assert(str.size() == std::strlen(str.c_str()));
+  UPB_ASSERT(str.size() == std::strlen(str.c_str()));
   return str.c_str();
 }
 
@@ -1459,19 +1459,19 @@ inline bool FieldDef::CheckIntegerFormat(int32_t val) {
   return upb_fielddef_checkintfmt(val);
 }
 inline FieldDef::Type FieldDef::ConvertType(int32_t val) {
-  assert(CheckType(val));
+  UPB_ASSERT(CheckType(val));
   return static_cast<FieldDef::Type>(val);
 }
 inline FieldDef::Label FieldDef::ConvertLabel(int32_t val) {
-  assert(CheckLabel(val));
+  UPB_ASSERT(CheckLabel(val));
   return static_cast<FieldDef::Label>(val);
 }
 inline FieldDef::DescriptorType FieldDef::ConvertDescriptorType(int32_t val) {
-  assert(CheckDescriptorType(val));
+  UPB_ASSERT(CheckDescriptorType(val));
   return static_cast<FieldDef::DescriptorType>(val);
 }
 inline FieldDef::IntegerFormat FieldDef::ConvertIntegerFormat(int32_t val) {
-  assert(CheckIntegerFormat(val));
+  UPB_ASSERT(CheckIntegerFormat(val));
   return static_cast<FieldDef::IntegerFormat>(val);
 }
 
diff --git a/upb/descriptor/descriptor.upbdefs.c b/upb/descriptor/descriptor.upbdefs.c
index d27adf4e82..da11d72d24 100644
--- a/upb/descriptor/descriptor.upbdefs.c
+++ b/upb/descriptor/descriptor.upbdefs.c
@@ -6,8 +6,6 @@
  * Do not edit -- your changes will be discarded when the file is
  * regenerated. */
 
-#include <assert.h>
-
 #include "upb/def.h"
 #include "upb/structdefs.int.h"
 
diff --git a/upb/descriptor/descriptor.upbdefs.h b/upb/descriptor/descriptor.upbdefs.h
index d8a22ca9c9..274c486a0e 100644
--- a/upb/descriptor/descriptor.upbdefs.h
+++ b/upb/descriptor/descriptor.upbdefs.h
@@ -184,111 +184,111 @@ UPB_INLINE bool upbdefs_google_protobuf_FileOptions_OptimizeMode_is(const upb_en
 
 
 /* Functions to get a fielddef from a msgdef reference. */
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_end(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_start(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_end(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_start(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_enum_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension_range(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_field(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_nested_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_oneof_decl(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_range(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_allow_alias(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_number(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_default_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_extendee(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_json_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_label(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_number(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_oneof_index(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_ctype(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_jstype(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_lazy(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_packed(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_weak(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_enum_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_message_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_public_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_service(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_source_code_info(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_syntax(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 12); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_weak_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorSet_f_file(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorSet_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_enable_arenas(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 31); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 16); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_csharp_namespace(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 37); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 23); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_go_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generate_equals_and_hash(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 20); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 17); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_multiple_files(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_outer_classname(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_string_check_utf8(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 27); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_javanano_use_deprecated_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 38); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_objc_class_prefix(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 36); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_optimize_for(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_py_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 18); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_map_entry(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_message_set_wire_format(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_no_standard_descriptor_accessor(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_client_streaming(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_input_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_output_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_server_streaming(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_OneofDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_OneofDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_method(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_detached_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_path(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_span(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_trailing_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_f_location(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_is_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_name_part(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_aggregate_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_double_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_identifier_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_negative_int_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_positive_int_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_string_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_end(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_start(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_end(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_start(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_enum_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension_range(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_field(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_nested_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_oneof_decl(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_range(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_allow_alias(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_number(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_default_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_extendee(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_json_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_label(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_number(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_oneof_index(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_ctype(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_jstype(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_lazy(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_packed(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_weak(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_enum_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_message_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_public_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_service(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_source_code_info(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_syntax(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 12); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_weak_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 11); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorSet_f_file(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorSet_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_enable_arenas(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 31); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 16); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_csharp_namespace(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 37); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 23); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_go_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 11); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generate_equals_and_hash(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 20); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 17); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_multiple_files(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_outer_classname(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_string_check_utf8(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 27); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_javanano_use_deprecated_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 38); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_objc_class_prefix(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 36); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_optimize_for(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_py_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 18); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_map_entry(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_message_set_wire_format(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_no_standard_descriptor_accessor(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_client_streaming(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_input_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_output_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_server_streaming(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 33); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_OneofDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_OneofDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_method(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 33); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_detached_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_path(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_span(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_trailing_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_f_location(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_is_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_name_part(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_aggregate_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_double_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_identifier_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_negative_int_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_positive_int_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_string_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 7); }
 
 UPB_END_EXTERN_C
 
@@ -302,7 +302,7 @@ class DescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   DescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_DescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m));
   }
 
   static DescriptorProto get() {
@@ -314,7 +314,7 @@ class DescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     ExtensionRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m));
+      UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m));
     }
 
     static ExtensionRange get() {
@@ -327,7 +327,7 @@ class DescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     ReservedRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m));
+      UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m));
     }
 
     static ReservedRange get() {
@@ -341,7 +341,7 @@ class EnumDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   EnumDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m));
   }
 
   static EnumDescriptorProto get() {
@@ -354,7 +354,7 @@ class EnumOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   EnumOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_EnumOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m));
   }
 
   static EnumOptions get() {
@@ -367,7 +367,7 @@ class EnumValueDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDe
  public:
   EnumValueDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m));
   }
 
   static EnumValueDescriptorProto get() {
@@ -380,7 +380,7 @@ class EnumValueOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   EnumValueOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_EnumValueOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m));
   }
 
   static EnumValueOptions get() {
@@ -393,7 +393,7 @@ class FieldDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   FieldDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m));
   }
 
   static FieldDescriptorProto get() {
@@ -405,7 +405,7 @@ class FieldDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     Label(const ::upb::EnumDef* e, const void *ref_donor = NULL)
         : reffed_ptr(e, ref_donor) {
-      assert(upbdefs_google_protobuf_FieldDescriptorProto_Label_is(e));
+      UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_Label_is(e));
     }
     static Label get() {
       const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Label_get(&e);
@@ -417,7 +417,7 @@ class FieldDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     Type(const ::upb::EnumDef* e, const void *ref_donor = NULL)
         : reffed_ptr(e, ref_donor) {
-      assert(upbdefs_google_protobuf_FieldDescriptorProto_Type_is(e));
+      UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_Type_is(e));
     }
     static Type get() {
       const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Type_get(&e);
@@ -430,7 +430,7 @@ class FieldOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   FieldOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_FieldOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m));
   }
 
   static FieldOptions get() {
@@ -442,7 +442,7 @@ class FieldOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     CType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
         : reffed_ptr(e, ref_donor) {
-      assert(upbdefs_google_protobuf_FieldOptions_CType_is(e));
+      UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_CType_is(e));
     }
     static CType get() {
       const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_CType_get(&e);
@@ -454,7 +454,7 @@ class FieldOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     JSType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
         : reffed_ptr(e, ref_donor) {
-      assert(upbdefs_google_protobuf_FieldOptions_JSType_is(e));
+      UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_JSType_is(e));
     }
     static JSType get() {
       const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_JSType_get(&e);
@@ -467,7 +467,7 @@ class FileDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   FileDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_FileDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m));
   }
 
   static FileDescriptorProto get() {
@@ -480,7 +480,7 @@ class FileDescriptorSet : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   FileDescriptorSet(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_FileDescriptorSet_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorSet_is(m));
   }
 
   static FileDescriptorSet get() {
@@ -493,7 +493,7 @@ class FileOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   FileOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_FileOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m));
   }
 
   static FileOptions get() {
@@ -505,7 +505,7 @@ class FileOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     OptimizeMode(const ::upb::EnumDef* e, const void *ref_donor = NULL)
         : reffed_ptr(e, ref_donor) {
-      assert(upbdefs_google_protobuf_FileOptions_OptimizeMode_is(e));
+      UPB_ASSERT(upbdefs_google_protobuf_FileOptions_OptimizeMode_is(e));
     }
     static OptimizeMode get() {
       const ::upb::EnumDef* e = upbdefs_google_protobuf_FileOptions_OptimizeMode_get(&e);
@@ -518,7 +518,7 @@ class MessageOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   MessageOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_MessageOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m));
   }
 
   static MessageOptions get() {
@@ -531,7 +531,7 @@ class MethodDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef>
  public:
   MethodDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m));
   }
 
   static MethodDescriptorProto get() {
@@ -544,7 +544,7 @@ class MethodOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   MethodOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_MethodOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m));
   }
 
   static MethodOptions get() {
@@ -557,7 +557,7 @@ class OneofDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   OneofDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_OneofDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_OneofDescriptorProto_is(m));
   }
 
   static OneofDescriptorProto get() {
@@ -570,7 +570,7 @@ class ServiceDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef>
  public:
   ServiceDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m));
   }
 
   static ServiceDescriptorProto get() {
@@ -583,7 +583,7 @@ class ServiceOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   ServiceOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_ServiceOptions_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m));
   }
 
   static ServiceOptions get() {
@@ -596,7 +596,7 @@ class SourceCodeInfo : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   SourceCodeInfo(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_SourceCodeInfo_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_is(m));
   }
 
   static SourceCodeInfo get() {
@@ -608,7 +608,7 @@ class SourceCodeInfo : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     Location(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m));
+      UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m));
     }
 
     static Location get() {
@@ -622,7 +622,7 @@ class UninterpretedOption : public ::upb::reffed_ptr<const ::upb::MessageDef> {
  public:
   UninterpretedOption(const ::upb::MessageDef* m, const void *ref_donor = NULL)
       : reffed_ptr(m, ref_donor) {
-    assert(upbdefs_google_protobuf_UninterpretedOption_is(m));
+    UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m));
   }
 
   static UninterpretedOption get() {
@@ -634,7 +634,7 @@ class UninterpretedOption : public ::upb::reffed_ptr<const ::upb::MessageDef> {
    public:
     NamePart(const ::upb::MessageDef* m, const void *ref_donor = NULL)
         : reffed_ptr(m, ref_donor) {
-      assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m));
+      UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m));
     }
 
     static NamePart get() {
diff --git a/upb/descriptor/reader.c b/upb/descriptor/reader.c
index 9717f1da3e..82fd57402d 100644
--- a/upb/descriptor/reader.c
+++ b/upb/descriptor/reader.c
@@ -111,9 +111,9 @@ static bool upb_descreader_qualify(upb_filedef *f, char *str, int32_t start) {
 
 static upb_msgdef *upb_descreader_top(upb_descreader *r) {
   int index;
-  assert(r->stack_len > 1);
+  UPB_ASSERT(r->stack_len > 1);
   index = r->stack[r->stack_len-1].start - 1;
-  assert(index >= 0);
+  UPB_ASSERT(index >= 0);
   return upb_downcast_msgdef_mutable(upb_filedef_mutabledef(r->file, index));
 }
 
@@ -183,7 +183,7 @@ static size_t file_onname(void *closure, const void *hd, const char *buf,
   /* XXX: see comment at the top of the file. */
   ok = upb_filedef_setname(r->file, name, NULL);
   upb_gfree(name);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return n;
 }
 
@@ -199,7 +199,7 @@ static size_t file_onpackage(void *closure, const void *hd, const char *buf,
   /* XXX: see comment at the top of the file. */
   upb_descreader_setscopename(r, package);
   ok = upb_filedef_setpackage(r->file, package, NULL);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return n;
 }
 
@@ -218,7 +218,7 @@ static size_t file_onsyntax(void *closure, const void *hd, const char *buf,
     ok = false;
   }
 
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return n;
 }
 
@@ -227,7 +227,7 @@ static void *file_startmsg(void *closure, const void *hd) {
   upb_msgdef *m = upb_msgdef_new(&m);
   bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
   UPB_UNUSED(hd);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return r;
 }
 
@@ -236,7 +236,7 @@ static void *file_startenum(void *closure, const void *hd) {
   upb_enumdef *e = upb_enumdef_new(&e);
   bool ok = upb_filedef_addenum(r->file, e, &e, NULL);
   UPB_UNUSED(hd);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return r;
 }
 
@@ -246,7 +246,7 @@ static void *file_startext(void *closure, const void *hd) {
   r->f = upb_fielddef_new(r);
   ok = upb_filedef_addext(r->file, r->f, r, NULL);
   UPB_UNUSED(hd);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return r;
 }
 
@@ -332,7 +332,7 @@ static size_t enum_onname(void *closure, const void *hd, const char *buf,
 static bool field_startmsg(void *closure, const void *hd) {
   upb_descreader *r = closure;
   UPB_UNUSED(hd);
-  assert(r->f);
+  UPB_ASSERT(r->f);
   upb_gfree(r->default_string);
   r->default_string = NULL;
 
@@ -418,9 +418,9 @@ static bool field_endmsg(void *closure, const void *hd, upb_status *status) {
   UPB_UNUSED(hd);
 
   /* TODO: verify that all required fields were present. */
-  assert(upb_fielddef_number(f) != 0);
-  assert(upb_fielddef_name(f) != NULL);
-  assert((upb_fielddef_subdefname(f) != NULL) == upb_fielddef_hassubdef(f));
+  UPB_ASSERT(upb_fielddef_number(f) != 0);
+  UPB_ASSERT(upb_fielddef_name(f) != NULL);
+  UPB_ASSERT((upb_fielddef_subdefname(f) != NULL) == upb_fielddef_hassubdef(f));
 
   if (r->default_string) {
     if (upb_fielddef_issubmsg(f)) {
@@ -479,7 +479,7 @@ static bool field_onnumber(void *closure, const void *hd, int32_t val) {
   UPB_UNUSED(hd);
 
   ok = upb_fielddef_setnumber(r->f, val, NULL);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return true;
 }
 
@@ -577,7 +577,7 @@ static void *msg_startmsg(void *closure, const void *hd) {
   upb_msgdef *m = upb_msgdef_new(&m);
   bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
   UPB_UNUSED(hd);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return r;
 }
 
@@ -586,7 +586,7 @@ static void *msg_startext(void *closure, const void *hd) {
   upb_fielddef *f = upb_fielddef_new(&f);
   bool ok = upb_filedef_addext(r->file, f, &f, NULL);
   UPB_UNUSED(hd);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return r;
 }
 
@@ -694,7 +694,7 @@ static void reghandlers(const void *closure, upb_handlers *h) {
     upb_handlers_setbool(h, F(MessageOptions, map_entry), &msg_onmapentry, NULL);
   }
 
-  assert(upb_ok(upb_handlers_status(h)));
+  UPB_ASSERT(upb_ok(upb_handlers_status(h)));
 }
 
 #undef F
diff --git a/upb/handlers-inl.h b/upb/handlers-inl.h
index 8cec602941..afc1382196 100644
--- a/upb/handlers-inl.h
+++ b/upb/handlers-inl.h
@@ -833,7 +833,7 @@ struct ConvertParams<BoundFunc5<R, P1, P2, P3, P4, P5, F, I>, T> {
   inline bool Handlers::SetValueHandler<vtype>(                                \
       const FieldDef *f,                                                       \
       const Handlers::utype ## Handler& handler) {                             \
-    assert(!handler.registered_);                                              \
+    UPB_ASSERT(!handler.registered_);                                              \
     handler.AddCleanup(this);                                                  \
     handler.registered_ = true;                                                \
     return upb_handlers_set##ltype(this, f, handler.handler_, &handler.attr_); \
@@ -945,7 +945,7 @@ inline Handler<T>::Handler(F func)
 
 template <class T>
 inline Handler<T>::~Handler() {
-  assert(registered_);
+  UPB_ASSERT(registered_);
 }
 
 inline HandlerAttributes::HandlerAttributes() { upb_handlerattr_init(this); }
@@ -1031,63 +1031,63 @@ inline bool Handlers::AddCleanup(void *p, upb_handlerfree *func) {
 }
 inline bool Handlers::SetStartMessageHandler(
     const Handlers::StartMessageHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setstartmsg(this, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetEndMessageHandler(
     const Handlers::EndMessageHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setendmsg(this, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetStartStringHandler(const FieldDef *f,
                                             const StartStringHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setstartstr(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetEndStringHandler(const FieldDef *f,
                                           const EndFieldHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setendstr(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetStringHandler(const FieldDef *f,
                                        const StringHandler& handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setstring(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetStartSequenceHandler(
     const FieldDef *f, const StartFieldHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setstartseq(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetStartSubMessageHandler(
     const FieldDef *f, const StartFieldHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setstartsubmsg(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetEndSubMessageHandler(const FieldDef *f,
                                               const EndFieldHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setendsubmsg(this, f, handler.handler_, &handler.attr_);
 }
 inline bool Handlers::SetEndSequenceHandler(const FieldDef *f,
                                             const EndFieldHandler &handler) {
-  assert(!handler.registered_);
+  UPB_ASSERT(!handler.registered_);
   handler.registered_ = true;
   handler.AddCleanup(this);
   return upb_handlers_setendseq(this, f, handler.handler_, &handler.attr_);
diff --git a/upb/handlers.c b/upb/handlers.c
index 055eadf5f2..09f9199a39 100644
--- a/upb/handlers.c
+++ b/upb/handlers.c
@@ -1,6 +1,6 @@
 /*
 ** TODO(haberman): it's unclear whether a lot of the consistency checks should
-** assert() or return false.
+** UPB_ASSERT() or return false.
 */
 
 #include "upb/handlers.h"
@@ -113,7 +113,7 @@ oom:
 static int32_t trygetsel(upb_handlers *h, const upb_fielddef *f,
                          upb_handlertype_t type) {
   upb_selector_t sel;
-  assert(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
   if (upb_handlers_msgdef(h) != upb_fielddef_containingtype(f)) {
     upb_status_seterrf(
         &h->status_, "type mismatch: field %s does not belong to message %s",
@@ -133,7 +133,7 @@ static int32_t trygetsel(upb_handlers *h, const upb_fielddef *f,
 static upb_selector_t handlers_getsel(upb_handlers *h, const upb_fielddef *f,
                              upb_handlertype_t type) {
   int32_t sel = trygetsel(h, f, type);
-  assert(sel >= 0);
+  UPB_ASSERT(sel >= 0);
   return sel;
 }
 
@@ -149,7 +149,7 @@ static bool doset(upb_handlers *h, int32_t sel, const upb_fielddef *f,
   const void *closure_type;
   const void **context_closure_type;
 
-  assert(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
 
   if (sel < 0) {
     upb_status_seterrmsg(&h->status_,
@@ -229,7 +229,7 @@ const void *effective_closure_type(upb_handlers *h, const upb_fielddef *f,
   const void *ret;
   upb_selector_t sel;
 
-  assert(type != UPB_HANDLER_STRING);
+  UPB_ASSERT(type != UPB_HANDLER_STRING);
   ret = h->top_closure_type;
 
   if (upb_fielddef_isseq(f) &&
@@ -284,7 +284,7 @@ upb_handlers *upb_handlers_new(const upb_msgdef *md, const void *owner) {
   int extra;
   upb_handlers *h;
 
-  assert(upb_msgdef_isfrozen(md));
+  UPB_ASSERT(upb_msgdef_isfrozen(md));
 
   extra = sizeof(upb_handlers_tabent) * (md->selector_count - 1);
   h = upb_calloc(sizeof(*h) + extra);
@@ -333,18 +333,18 @@ const upb_handlers *upb_handlers_newfrozen(const upb_msgdef *m,
 
   r = upb_handlers_upcast_mutable(ret);
   ok = upb_refcounted_freeze(&r, 1, NULL, UPB_MAX_HANDLER_DEPTH);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
 
   return ret;
 }
 
 const upb_status *upb_handlers_status(upb_handlers *h) {
-  assert(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
   return &h->status_;
 }
 
 void upb_handlers_clearerr(upb_handlers *h) {
-  assert(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
   upb_status_clear(&h->status_);
 }
 
@@ -380,16 +380,16 @@ bool upb_handlers_setstartmsg(upb_handlers *h, upb_startmsg_handlerfunc *func,
 
 bool upb_handlers_setendmsg(upb_handlers *h, upb_endmsg_handlerfunc *func,
                             upb_handlerattr *attr) {
-  assert(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
   return doset(h, UPB_ENDMSG_SELECTOR, NULL, UPB_HANDLER_INT32,
                (upb_func *)func, attr);
 }
 
 bool upb_handlers_setsubhandlers(upb_handlers *h, const upb_fielddef *f,
                                  const upb_handlers *sub) {
-  assert(sub);
-  assert(!upb_handlers_isfrozen(h));
-  assert(upb_fielddef_issubmsg(f));
+  UPB_ASSERT(sub);
+  UPB_ASSERT(!upb_handlers_isfrozen(h));
+  UPB_ASSERT(upb_fielddef_issubmsg(f));
   if (SUBH_F(h, f)) return false;  /* Can't reset. */
   if (upb_msgdef_upcast(upb_handlers_msgdef(sub)) != upb_fielddef_subdef(f)) {
     return false;
@@ -401,7 +401,7 @@ bool upb_handlers_setsubhandlers(upb_handlers *h, const upb_fielddef *f,
 
 const upb_handlers *upb_handlers_getsubhandlers(const upb_handlers *h,
                                                 const upb_fielddef *f) {
-  assert(upb_fielddef_issubmsg(f));
+  UPB_ASSERT(upb_fielddef_issubmsg(f));
   return SUBH_F(h, f);
 }
 
@@ -427,7 +427,7 @@ bool upb_handlers_addcleanup(upb_handlers *h, void *p, upb_handlerfree *func) {
     return false;
   }
   ok = upb_inttable_insertptr(&h->cleanup_, p, upb_value_fptr(func));
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return true;
 }
 
@@ -528,7 +528,7 @@ upb_handlertype_t upb_handlers_getprimitivehandlertype(const upb_fielddef *f) {
     case UPB_TYPE_FLOAT: return UPB_HANDLER_FLOAT;
     case UPB_TYPE_DOUBLE: return UPB_HANDLER_DOUBLE;
     case UPB_TYPE_BOOL: return UPB_HANDLER_BOOL;
-    default: assert(false); return -1;  /* Invalid input. */
+    default: UPB_ASSERT(false); return -1;  /* Invalid input. */
   }
 }
 
@@ -591,7 +591,7 @@ bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
       *s = f->selector_base;
       break;
   }
-  assert((size_t)*s < upb_fielddef_containingtype(f)->selector_count);
+  UPB_ASSERT((size_t)*s < upb_fielddef_containingtype(f)->selector_count);
   return true;
 }
 
diff --git a/upb/handlers.h b/upb/handlers.h
index 8925d4fcf3..54a3c1c45a 100644
--- a/upb/handlers.h
+++ b/upb/handlers.h
@@ -611,7 +611,7 @@ template <class T> class Handler {
   void AddCleanup(Handlers* h) const {
     if (cleanup_func_) {
       bool ok = h->AddCleanup(cleanup_data_, cleanup_func_);
-      UPB_ASSERT_VAR(ok, ok);
+      UPB_ASSERT(ok);
     }
   }
 
diff --git a/upb/json/parser.c b/upb/json/parser.c
index a808616abe..9ee67c1397 100644
--- a/upb/json/parser.c
+++ b/upb/json/parser.c
@@ -119,7 +119,7 @@ static upb_selector_t getsel_for_handlertype(upb_json_parser *p,
                                              upb_handlertype_t type) {
   upb_selector_t sel;
   bool ok = upb_handlers_getselector(p->top->f, type, &sel);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return sel;
 }
 
@@ -141,7 +141,7 @@ static bool check_stack(upb_json_parser *p) {
 static void set_name_table(upb_json_parser *p, upb_jsonparser_frame *frame) {
   upb_value v;
   bool ok = upb_inttable_lookupptr(&p->method->name_tables, frame->m, &v);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   frame->name_table = upb_value_getptr(v);
 }
 
@@ -264,7 +264,7 @@ otherchar:
     val = b64lookup(ptr[0]) << 18 |
           b64lookup(ptr[1]) << 12;
 
-    assert(!(val & 0x80000000));
+    UPB_ASSERT(!(val & 0x80000000));
     output = val >> 16;
     upb_sink_putstring(&p->top->sink, sel, &output, 1, NULL);
     return true;
@@ -319,8 +319,8 @@ badpadding:
 
 static void assert_accumulate_empty(upb_json_parser *p) {
   UPB_UNUSED(p);
-  assert(p->accumulated == NULL);
-  assert(p->accumulated_len == 0);
+  UPB_ASSERT(p->accumulated == NULL);
+  UPB_ASSERT(p->accumulated_len == 0);
 }
 
 static void accumulate_clear(upb_json_parser *p) {
@@ -386,7 +386,7 @@ static bool accumulate_append(upb_json_parser *p, const char *buf, size_t len,
  * call, and writes the length to *len.  This with point either to the input
  * buffer or a temporary accumulate buffer. */
 static const char *accumulate_getptr(upb_json_parser *p, size_t *len) {
-  assert(p->accumulated);
+  UPB_ASSERT(p->accumulated);
   *len = p->accumulated_len;
   return p->accumulated;
 }
@@ -424,7 +424,7 @@ enum {
  * the end. */
 static void multipart_startaccum(upb_json_parser *p) {
   assert_accumulate_empty(p);
-  assert(p->multipart_state == MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_ACCUMULATE;
 }
 
@@ -432,7 +432,7 @@ static void multipart_startaccum(upb_json_parser *p) {
  * value with the given selector. */
 static void multipart_start(upb_json_parser *p, upb_selector_t sel) {
   assert_accumulate_empty(p);
-  assert(p->multipart_state == MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_PUSHEAGERLY;
   p->string_selector = sel;
 }
@@ -465,7 +465,7 @@ static bool multipart_text(upb_json_parser *p, const char *buf, size_t len,
 /* Note: this invalidates the accumulate buffer!  Call only after reading its
  * contents. */
 static void multipart_end(upb_json_parser *p) {
-  assert(p->multipart_state != MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_INACTIVE;
   accumulate_clear(p);
 }
@@ -478,13 +478,13 @@ static void multipart_end(upb_json_parser *p) {
  * region. */
 
 static void capture_begin(upb_json_parser *p, const char *ptr) {
-  assert(p->multipart_state != MULTIPART_INACTIVE);
-  assert(p->capture == NULL);
+  UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
+  UPB_ASSERT(p->capture == NULL);
   p->capture = ptr;
 }
 
 static bool capture_end(upb_json_parser *p, const char *ptr) {
-  assert(p->capture);
+  UPB_ASSERT(p->capture);
   if (multipart_text(p, p->capture, ptr - p->capture, true)) {
     p->capture = NULL;
     return true;
@@ -517,7 +517,7 @@ static void capture_suspend(upb_json_parser *p, const char **ptr) {
 
 static void capture_resume(upb_json_parser *p, const char *ptr) {
   if (p->capture) {
-    assert(p->capture == &suspend_capture);
+    UPB_ASSERT(p->capture == &suspend_capture);
     p->capture = ptr;
   }
 }
@@ -539,7 +539,7 @@ static char escape_char(char in) {
     case '"': return '"';
     case '\\': return '\\';
     default:
-      assert(0);
+      UPB_ASSERT(0);
       return 'x';
   }
 }
@@ -563,7 +563,7 @@ static void hexdigit(upb_json_parser *p, const char *ptr) {
   } else if (ch >= 'a' && ch <= 'f') {
     p->digit += ((ch - 'a') + 10);
   } else {
-    assert(ch >= 'A' && ch <= 'F');
+    UPB_ASSERT(ch >= 'A' && ch <= 'F');
     p->digit += ((ch - 'A') + 10);
   }
 }
@@ -694,7 +694,7 @@ static bool parse_number(upb_json_parser *p) {
       break;
     }
     default:
-      assert(false);
+      UPB_ASSERT(false);
   }
 
   multipart_end(p);
@@ -720,13 +720,13 @@ static bool parser_putbool(upb_json_parser *p, bool val) {
   }
 
   ok = upb_sink_putbool(&p->top->sink, parser_getsel(p), val);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
 
   return true;
 }
 
 static bool start_stringval(upb_json_parser *p) {
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (upb_fielddef_isstring(p->top->f)) {
     upb_jsonparser_frame *inner;
@@ -816,7 +816,7 @@ static bool end_stringval(upb_json_parser *p) {
     }
 
     default:
-      assert(false);
+      UPB_ASSERT(false);
       upb_status_seterrmsg(&p->status, "Internal error in JSON decoder");
       upb_env_reporterror(p->env, &p->status);
       ok = false;
@@ -829,7 +829,7 @@ static bool end_stringval(upb_json_parser *p) {
 }
 
 static void start_member(upb_json_parser *p) {
-  assert(!p->top->f);
+  UPB_ASSERT(!p->top->f);
   multipart_startaccum(p);
 }
 
@@ -958,7 +958,7 @@ static bool handle_mapentry(upb_json_parser *p) {
 }
 
 static bool end_membername(upb_json_parser *p) {
-  assert(!p->top->f);
+  UPB_ASSERT(!p->top->f);
 
   if (p->top->is_map) {
     return handle_mapentry(p);
@@ -990,7 +990,7 @@ static void end_member(upb_json_parser *p) {
     bool ok;
     const upb_fielddef *mapfield;
 
-    assert(p->top > p->stack);
+    UPB_ASSERT(p->top > p->stack);
     /* send ENDMSG on submsg. */
     upb_sink_endmsg(&p->top->sink, &s);
     mapfield = p->top->mapfield;
@@ -998,7 +998,7 @@ static void end_member(upb_json_parser *p) {
     /* send ENDSUBMSG in repeated-field-of-mapentries frame. */
     p->top--;
     ok = upb_handlers_getselector(mapfield, UPB_HANDLER_ENDSUBMSG, &sel);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
     upb_sink_endsubmsg(&p->top->sink, sel);
   }
 
@@ -1006,7 +1006,7 @@ static void end_member(upb_json_parser *p) {
 }
 
 static bool start_subobject(upb_json_parser *p) {
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (upb_fielddef_ismap(p->top->f)) {
     upb_jsonparser_frame *inner;
@@ -1075,7 +1075,7 @@ static bool start_array(upb_json_parser *p) {
   upb_jsonparser_frame *inner;
   upb_selector_t sel;
 
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (!upb_fielddef_isseq(p->top->f)) {
     upb_status_seterrf(&p->status,
@@ -1103,7 +1103,7 @@ static bool start_array(upb_json_parser *p) {
 static void end_array(upb_json_parser *p) {
   upb_selector_t sel;
 
-  assert(p->top > p->stack);
+  UPB_ASSERT(p->top > p->stack);
 
   p->top--;
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
@@ -1634,7 +1634,7 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
       buf = upb_grealloc(buf, 0, field_len);
       len = field_len;
       len2 = upb_fielddef_getjsonname(f, buf, len);
-      UPB_ASSERT_VAR(len2, len == len2);
+      UPB_ASSERT(len == len2);
     }
     upb_strtable_insert(t, buf, upb_value_constptr(f));
 
@@ -1678,7 +1678,8 @@ upb_json_parser *upb_json_parser_create(upb_env *env,
 
   /* If this fails, uncomment and increase the value in parser.h. */
   /* fprintf(stderr, "%zd\n", upb_env_bytesallocated(env) - size_before); */
-  assert(upb_env_bytesallocated(env) - size_before <= UPB_JSON_PARSER_SIZE);
+  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(env) - size_before <=
+                      UPB_JSON_PARSER_SIZE);
   return p;
 }
 
diff --git a/upb/json/parser.rl b/upb/json/parser.rl
index b67f08d1db..b0fcdba561 100644
--- a/upb/json/parser.rl
+++ b/upb/json/parser.rl
@@ -117,7 +117,7 @@ static upb_selector_t getsel_for_handlertype(upb_json_parser *p,
                                              upb_handlertype_t type) {
   upb_selector_t sel;
   bool ok = upb_handlers_getselector(p->top->f, type, &sel);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return sel;
 }
 
@@ -139,7 +139,7 @@ static bool check_stack(upb_json_parser *p) {
 static void set_name_table(upb_json_parser *p, upb_jsonparser_frame *frame) {
   upb_value v;
   bool ok = upb_inttable_lookupptr(&p->method->name_tables, frame->m, &v);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   frame->name_table = upb_value_getptr(v);
 }
 
@@ -262,7 +262,7 @@ otherchar:
     val = b64lookup(ptr[0]) << 18 |
           b64lookup(ptr[1]) << 12;
 
-    assert(!(val & 0x80000000));
+    UPB_ASSERT(!(val & 0x80000000));
     output = val >> 16;
     upb_sink_putstring(&p->top->sink, sel, &output, 1, NULL);
     return true;
@@ -316,9 +316,8 @@ badpadding:
  *      the true value in a contiguous buffer. */
 
 static void assert_accumulate_empty(upb_json_parser *p) {
-  UPB_UNUSED(p);
-  assert(p->accumulated == NULL);
-  assert(p->accumulated_len == 0);
+  UPB_ASSERT(p->accumulated == NULL);
+  UPB_ASSERT(p->accumulated_len == 0);
 }
 
 static void accumulate_clear(upb_json_parser *p) {
@@ -384,7 +383,7 @@ static bool accumulate_append(upb_json_parser *p, const char *buf, size_t len,
  * call, and writes the length to *len.  This with point either to the input
  * buffer or a temporary accumulate buffer. */
 static const char *accumulate_getptr(upb_json_parser *p, size_t *len) {
-  assert(p->accumulated);
+  UPB_ASSERT(p->accumulated);
   *len = p->accumulated_len;
   return p->accumulated;
 }
@@ -422,7 +421,7 @@ enum {
  * the end. */
 static void multipart_startaccum(upb_json_parser *p) {
   assert_accumulate_empty(p);
-  assert(p->multipart_state == MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_ACCUMULATE;
 }
 
@@ -430,7 +429,7 @@ static void multipart_startaccum(upb_json_parser *p) {
  * value with the given selector. */
 static void multipart_start(upb_json_parser *p, upb_selector_t sel) {
   assert_accumulate_empty(p);
-  assert(p->multipart_state == MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_PUSHEAGERLY;
   p->string_selector = sel;
 }
@@ -463,7 +462,7 @@ static bool multipart_text(upb_json_parser *p, const char *buf, size_t len,
 /* Note: this invalidates the accumulate buffer!  Call only after reading its
  * contents. */
 static void multipart_end(upb_json_parser *p) {
-  assert(p->multipart_state != MULTIPART_INACTIVE);
+  UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
   p->multipart_state = MULTIPART_INACTIVE;
   accumulate_clear(p);
 }
@@ -476,13 +475,13 @@ static void multipart_end(upb_json_parser *p) {
  * region. */
 
 static void capture_begin(upb_json_parser *p, const char *ptr) {
-  assert(p->multipart_state != MULTIPART_INACTIVE);
-  assert(p->capture == NULL);
+  UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
+  UPB_ASSERT(p->capture == NULL);
   p->capture = ptr;
 }
 
 static bool capture_end(upb_json_parser *p, const char *ptr) {
-  assert(p->capture);
+  UPB_ASSERT(p->capture);
   if (multipart_text(p, p->capture, ptr - p->capture, true)) {
     p->capture = NULL;
     return true;
@@ -515,7 +514,7 @@ static void capture_suspend(upb_json_parser *p, const char **ptr) {
 
 static void capture_resume(upb_json_parser *p, const char *ptr) {
   if (p->capture) {
-    assert(p->capture == &suspend_capture);
+    UPB_ASSERT(p->capture == &suspend_capture);
     p->capture = ptr;
   }
 }
@@ -537,7 +536,7 @@ static char escape_char(char in) {
     case '"': return '"';
     case '\\': return '\\';
     default:
-      assert(0);
+      UPB_ASSERT(0);
       return 'x';
   }
 }
@@ -561,7 +560,7 @@ static void hexdigit(upb_json_parser *p, const char *ptr) {
   } else if (ch >= 'a' && ch <= 'f') {
     p->digit += ((ch - 'a') + 10);
   } else {
-    assert(ch >= 'A' && ch <= 'F');
+    UPB_ASSERT(ch >= 'A' && ch <= 'F');
     p->digit += ((ch - 'A') + 10);
   }
 }
@@ -692,7 +691,7 @@ static bool parse_number(upb_json_parser *p) {
       break;
     }
     default:
-      assert(false);
+      UPB_ASSERT(false);
   }
 
   multipart_end(p);
@@ -718,13 +717,13 @@ static bool parser_putbool(upb_json_parser *p, bool val) {
   }
 
   ok = upb_sink_putbool(&p->top->sink, parser_getsel(p), val);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
 
   return true;
 }
 
 static bool start_stringval(upb_json_parser *p) {
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (upb_fielddef_isstring(p->top->f)) {
     upb_jsonparser_frame *inner;
@@ -814,7 +813,7 @@ static bool end_stringval(upb_json_parser *p) {
     }
 
     default:
-      assert(false);
+      UPB_ASSERT(false);
       upb_status_seterrmsg(&p->status, "Internal error in JSON decoder");
       upb_env_reporterror(p->env, &p->status);
       ok = false;
@@ -827,7 +826,7 @@ static bool end_stringval(upb_json_parser *p) {
 }
 
 static void start_member(upb_json_parser *p) {
-  assert(!p->top->f);
+  UPB_ASSERT(!p->top->f);
   multipart_startaccum(p);
 }
 
@@ -956,7 +955,7 @@ static bool handle_mapentry(upb_json_parser *p) {
 }
 
 static bool end_membername(upb_json_parser *p) {
-  assert(!p->top->f);
+  UPB_ASSERT(!p->top->f);
 
   if (p->top->is_map) {
     return handle_mapentry(p);
@@ -988,7 +987,7 @@ static void end_member(upb_json_parser *p) {
     bool ok;
     const upb_fielddef *mapfield;
 
-    assert(p->top > p->stack);
+    UPB_ASSERT(p->top > p->stack);
     /* send ENDMSG on submsg. */
     upb_sink_endmsg(&p->top->sink, &s);
     mapfield = p->top->mapfield;
@@ -996,7 +995,7 @@ static void end_member(upb_json_parser *p) {
     /* send ENDSUBMSG in repeated-field-of-mapentries frame. */
     p->top--;
     ok = upb_handlers_getselector(mapfield, UPB_HANDLER_ENDSUBMSG, &sel);
-    UPB_ASSERT_VAR(ok, ok);
+    UPB_ASSERT(ok);
     upb_sink_endsubmsg(&p->top->sink, sel);
   }
 
@@ -1004,7 +1003,7 @@ static void end_member(upb_json_parser *p) {
 }
 
 static bool start_subobject(upb_json_parser *p) {
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (upb_fielddef_ismap(p->top->f)) {
     upb_jsonparser_frame *inner;
@@ -1073,7 +1072,7 @@ static bool start_array(upb_json_parser *p) {
   upb_jsonparser_frame *inner;
   upb_selector_t sel;
 
-  assert(p->top->f);
+  UPB_ASSERT(p->top->f);
 
   if (!upb_fielddef_isseq(p->top->f)) {
     upb_status_seterrf(&p->status,
@@ -1101,7 +1100,7 @@ static bool start_array(upb_json_parser *p) {
 static void end_array(upb_json_parser *p) {
   upb_selector_t sel;
 
-  assert(p->top > p->stack);
+  UPB_ASSERT(p->top > p->stack);
 
   p->top--;
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
@@ -1369,7 +1368,7 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
       buf = upb_grealloc(buf, 0, field_len);
       len = field_len;
       len2 = upb_fielddef_getjsonname(f, buf, len);
-      UPB_ASSERT_VAR(len2, len == len2);
+      UPB_ASSERT(len == len2);
     }
     upb_strtable_insert(t, buf, upb_value_constptr(f));
 
@@ -1413,7 +1412,8 @@ upb_json_parser *upb_json_parser_create(upb_env *env,
 
   /* If this fails, uncomment and increase the value in parser.h. */
   /* fprintf(stderr, "%zd\n", upb_env_bytesallocated(env) - size_before); */
-  assert(upb_env_bytesallocated(env) - size_before <= UPB_JSON_PARSER_SIZE);
+  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(env) - size_before <=
+                      UPB_JSON_PARSER_SIZE);
   return p;
 }
 
diff --git a/upb/json/printer.c b/upb/json/printer.c
index cc50417923..0f9ca0e109 100644
--- a/upb/json/printer.c
+++ b/upb/json/printer.c
@@ -54,7 +54,7 @@ strpc *newstrpc(upb_handlers *h, const upb_fielddef *f,
     ret->len = upb_fielddef_getjsonname(f, NULL, 0);
     ret->ptr = upb_gmalloc(ret->len);
     len = upb_fielddef_getjsonname(f, ret->ptr, ret->len);
-    UPB_ASSERT_VAR(len, len == ret->len);
+    UPB_ASSERT(len == ret->len);
     ret->len--;  /* NULL */
   }
 
@@ -68,7 +68,7 @@ static void print_data(
     upb_json_printer *p, const char *buf, unsigned int len) {
   /* TODO: Will need to change if we support pushback from the sink. */
   size_t n = upb_bytessink_putbuf(p->output_, p->subc_, buf, len, NULL);
-  UPB_ASSERT_VAR(n, n == len);
+  UPB_ASSERT(n == len);
 }
 
 static void print_comma(upb_json_printer *p) {
@@ -418,7 +418,7 @@ static size_t putbytes(void *closure, const void *handler_data, const char *str,
 
   while (remaining > 2) {
     /* TODO(haberman): handle encoded lengths > sizeof(data) */
-    UPB_ASSERT_VAR(limit, (limit - to) >= 4);
+    UPB_ASSERT((limit - to) >= 4);
 
     to[0] = base64[from[0] >> 2];
     to[1] = base64[((from[0] & 0x3) << 4) | (from[1] >> 4)];
@@ -622,7 +622,7 @@ void printer_sethandlers_mapentry(const void *closure, bool preserve_fieldnames,
       upb_handlers_setstring(h, key_field, mapkey_bytes, &empty_attr);
       break;
     default:
-      assert(false);
+      UPB_ASSERT(false);
       break;
   }
 
@@ -796,7 +796,8 @@ upb_json_printer *upb_json_printer_create(upb_env *e, const upb_handlers *h,
   upb_sink_reset(&p->input_, h, p);
 
   /* If this fails, increase the value in printer.h. */
-  assert(upb_env_bytesallocated(e) - size_before <= UPB_JSON_PRINTER_SIZE);
+  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(e) - size_before <=
+                      UPB_JSON_PRINTER_SIZE);
   return p;
 }
 
diff --git a/upb/pb/compile_decoder.c b/upb/pb/compile_decoder.c
index 7724113e25..d86f840a39 100644
--- a/upb/pb/compile_decoder.c
+++ b/upb/pb/compile_decoder.c
@@ -183,7 +183,7 @@ bool op_has_longofs(int32_t instruction) {
     case OP_TAGN:
       return false;
     default:
-      assert(false);
+      UPB_ASSERT(false);
       return false;
   }
 }
@@ -202,7 +202,7 @@ static void setofs(uint32_t *instruction, int32_t ofs) {
   } else {
     *instruction = (*instruction & ~0xff00) | ((ofs & 0xff) << 8);
   }
-  assert(getofs(*instruction) == ofs);  /* Would fail in cases of overflow. */
+  UPB_ASSERT(getofs(*instruction) == ofs);  /* Would fail in cases of overflow. */
 }
 
 static uint32_t pcofs(compiler *c) { return c->pc - c->group->bytecode; }
@@ -214,7 +214,7 @@ static void label(compiler *c, unsigned int label) {
   int val;
   uint32_t *codep;
 
-  assert(label < MAXLABEL);
+  UPB_ASSERT(label < MAXLABEL);
   val = c->fwd_labels[label];
   codep = (val == EMPTYLABEL) ? NULL : c->group->bytecode + val;
   while (codep) {
@@ -235,7 +235,7 @@ static void label(compiler *c, unsigned int label) {
  * The returned value is the offset that should be written into the instruction.
  */
 static int32_t labelref(compiler *c, int label) {
-  assert(label < MAXLABEL);
+  UPB_ASSERT(label < MAXLABEL);
   if (label == LABEL_DISPATCH) {
     /* No resolving required. */
     return 0;
@@ -335,7 +335,7 @@ static void putop(compiler *c, opcode op, ...) {
       int label = va_arg(ap, int);
       uint64_t tag = va_arg(ap, uint64_t);
       uint32_t instruction = op | (tag << 16);
-      assert(tag <= 0xffff);
+      UPB_ASSERT(tag <= 0xffff);
       setofs(&instruction, labelref(c, label));
       put32(c, instruction);
       break;
@@ -472,7 +472,7 @@ static uint64_t get_encoded_tag(const upb_fielddef *f, int wire_type) {
   uint32_t tag = (upb_fielddef_number(f) << 3) | wire_type;
   uint64_t encoded_tag = upb_vencode32(tag);
   /* No tag should be greater than 5 bytes. */
-  assert(encoded_tag <= 0xffffffffff);
+  UPB_ASSERT(encoded_tag <= 0xffffffffff);
   return encoded_tag;
 }
 
@@ -495,7 +495,7 @@ static void putchecktag(compiler *c, const upb_fielddef *f,
 static upb_selector_t getsel(const upb_fielddef *f, upb_handlertype_t type) {
   upb_selector_t selector;
   bool ok = upb_handlers_getselector(f, type, &selector);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return selector;
 }
 
@@ -507,7 +507,7 @@ static uint64_t repack(uint64_t dispatch, int new_wt2) {
   uint8_t wt1;
   uint8_t old_wt2;
   upb_pbdecoder_unpackdispatch(dispatch, &ofs, &wt1, &old_wt2);
-  assert(old_wt2 == NO_WIRE_TYPE);  /* wt2 should not be set yet. */
+  UPB_ASSERT(old_wt2 == NO_WIRE_TYPE);  /* wt2 should not be set yet. */
   return upb_pbdecoder_packdispatch(ofs, wt1, new_wt2);
 }
 
@@ -709,7 +709,7 @@ static void generate_primitivefield(compiler *c, const upb_fielddef *f,
    * setting in the fielddef.  This will favor (in speed) whichever was
    * specified. */
 
-  assert((int)parse_type >= 0 && parse_type <= OP_MAX);
+  UPB_ASSERT((int)parse_type >= 0 && parse_type <= OP_MAX);
   sel = getsel(f, upb_handlers_getprimitivehandlertype(f));
   wire_type = upb_pb_native_wire_types[upb_fielddef_descriptortype(f)];
   if (upb_fielddef_isseq(f)) {
@@ -751,7 +751,7 @@ static void compile_method(compiler *c, upb_pbdecodermethod *method) {
   upb_msg_field_iter i;
   upb_value val;
 
-  assert(method);
+  UPB_ASSERT(method);
 
   /* Clear all entries in the dispatch table. */
   upb_inttable_uninit(&method->dispatch);
@@ -899,7 +899,7 @@ const mgroup *mgroup_new(const upb_handlers *dest, bool allowjit, bool lazy,
   compiler *c;
 
   UPB_UNUSED(allowjit);
-  assert(upb_handlers_isfrozen(dest));
+  UPB_ASSERT(upb_handlers_isfrozen(dest));
 
   g = newgroup(owner);
   c = newcompiler(g, lazy);
@@ -920,13 +920,13 @@ const mgroup *mgroup_new(const upb_handlers *dest, bool allowjit, bool lazy,
 #ifdef UPB_DUMP_BYTECODE
   {
     FILE *f = fopen("/tmp/upb-bytecode", "w");
-    assert(f);
+    UPB_ASSERT(f);
     dumpbc(g->bytecode, g->bytecode_end, stderr);
     dumpbc(g->bytecode, g->bytecode_end, f);
     fclose(f);
 
     f = fopen("/tmp/upb-bytecode.bin", "wb");
-    assert(f);
+    UPB_ASSERT(f);
     fwrite(g->bytecode, 1, g->bytecode_end - g->bytecode, f);
     fclose(f);
   }
@@ -976,7 +976,7 @@ const upb_pbdecodermethod *upb_pbcodecache_getdecodermethod(
   upb_inttable_push(&c->groups, upb_value_constptr(g));
 
   ok = upb_inttable_lookupptr(&g->methods, opts->handlers, &v);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return upb_value_getptr(v);
 }
 
diff --git a/upb/pb/compile_decoder_x64.c b/upb/pb/compile_decoder_x64.c
index 88561d681b..29dbcb1106 100644
--- a/upb/pb/compile_decoder_x64.c
+++ b/upb/pb/compile_decoder_x64.c
@@ -184,7 +184,7 @@ static char *upb_vasprintf(const char *fmt, va_list args) {
   char *ret = malloc(len + 1);  /* + 1 for NULL terminator. */
   if (!ret) abort();
   int written = _upb_vsnprintf(ret, len + 1, fmt, args);
-  UPB_ASSERT_VAR(written, written == len);
+  UPB_ASSERT(written == len);
 
   return ret;
 }
@@ -221,9 +221,9 @@ static int getjmptarget(jitcompiler *jc, const void *key) {
   int pclabel = 0;
   bool ok;
 
-  assert(upb_inttable_lookupptr(&jc->jmpdefined, key, NULL));
+  UPB_ASSERT_DEBUGVAR(upb_inttable_lookupptr(&jc->jmpdefined, key, NULL));
   ok = try_getjmptarget(jc, key, &pclabel);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return pclabel;
 }
 
@@ -289,10 +289,10 @@ uint32_t dispatchofs(jitcompiler *jc, const upb_pbdecodermethod *method,
   int mc_target = machine_code_ofs2(jc, method, pcofs);
   int ret;
 
-  assert(mc_base > 0);
-  assert(mc_target > 0);
+  UPB_ASSERT(mc_base > 0);
+  UPB_ASSERT(mc_target > 0);
   ret = mc_target - mc_base;
-  assert(ret > 0);
+  UPB_ASSERT(ret > 0);
   return ret;
 }
 
@@ -327,7 +327,7 @@ static void patchdispatch(jitcompiler *jc) {
         /* Update offset and repack. */
         ofs = dispatchofs(jc, method, ofs);
         newval = upb_pbdecoder_packdispatch(ofs, wt1, wt2);
-        assert((int64_t)newval > 0);
+        UPB_ASSERT((int64_t)newval > 0);
       } else {
         /* Secondary slot.  Since we have 64 bits for the value, we use an
          * absolute offset. */
@@ -335,7 +335,7 @@ static void patchdispatch(jitcompiler *jc) {
         newval = (uint64_t)((char*)jc->group->jit_code + mcofs);
       }
       ok = upb_inttable_replace(dispatch, key, upb_value_uint64(newval));
-      UPB_ASSERT_VAR(ok, ok);
+      UPB_ASSERT(ok);
     }
 
     /* Update entry point for this method to point at mc base instead of bc
@@ -467,7 +467,7 @@ void upb_pbdecoder_jit(mgroup *group) {
   group->debug_info = NULL;
   group->dl = NULL;
 
-  assert(group->bytecode);
+  UPB_ASSERT(group->bytecode);
   jc = newjitcompiler(group);
   emit_static_asm(jc);
   jitbytecode(jc);
diff --git a/upb/pb/compile_decoder_x64.dasc b/upb/pb/compile_decoder_x64.dasc
index edda7dd1eb..512c1740a2 100644
--- a/upb/pb/compile_decoder_x64.dasc
+++ b/upb/pb/compile_decoder_x64.dasc
@@ -153,7 +153,7 @@ static upb_func *gethandler(const upb_handlers *h, upb_selector_t sel) {
 static void asmlabel(jitcompiler *jc, const char *fmt, ...) {
 #ifndef NDEBUG
   int ofs = jc->dynasm->section->ofs;
-  assert(ofs != jc->lastlabelofs);
+  UPB_ASSERT(ofs != jc->lastlabelofs);
   jc->lastlabelofs = ofs;
 #endif
 
@@ -183,7 +183,7 @@ static bool alwaysok(const upb_handlers *h, upb_selector_t sel) {
   bool ok = upb_handlers_getattr(h, sel, &attr);
   bool ret;
 
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   ret = upb_handlerattr_alwaysok(&attr);
   upb_handlerattr_uninit(&attr);
   return ret;
@@ -641,7 +641,7 @@ static void jitprimitive(jitcompiler *jc, opcode op,
         case UPB_TYPE_STRING:
         case UPB_TYPE_BYTES:
         case UPB_TYPE_MESSAGE:
-          assert(false); break;
+          UPB_ASSERT(false); break;
       }
       |  sethas CLOSURE, data->hasbit
     } else if (handler) {
@@ -790,7 +790,7 @@ static void jitdispatch(jitcompiler *jc,
     |  // Secondary wire type is a match, look up fn + UPB_MAX_FIELDNUMBER.
     |  add   rdx, UPB_MAX_FIELDNUMBER
     |  // This key will never be in the array part, so do a hash lookup.
-    assert(has_hash_entries);
+    UPB_ASSERT(has_hash_entries);
     |  ld64  dispatch
     |  jmp   ->hashlookup  // Tail call.
   }
@@ -815,7 +815,7 @@ static void jittag(jitcompiler *jc, uint64_t tag, int n, int ofs,
   uint32_t *delimend = (jc->pc - 1) + last_arg;
   const size_t ptr_words = sizeof(void*) / sizeof(uint32_t);
 
-  assert((last_instruction & 0xff) == OP_CHECKDELIM);
+  UPB_ASSERT((last_instruction & 0xff) == OP_CHECKDELIM);
 
   if (getop(*(jc->pc - 1)) == OP_TAGN) {
     jc->pc += ptr_words;
@@ -1131,7 +1131,7 @@ static void jitbytecode(jitcompiler *jc) {
       |  call   =>jmptarget(jc, &method->dispatch)
       break;
     case OP_HALT:
-      assert(false);
+      UPB_ASSERT(false);
     }
   }
 
diff --git a/upb/pb/compile_decoder_x64.h b/upb/pb/compile_decoder_x64.h
index 5d2b95a9d8..ce775c684d 100644
--- a/upb/pb/compile_decoder_x64.h
+++ b/upb/pb/compile_decoder_x64.h
@@ -338,7 +338,7 @@ static upb_func *gethandler(const upb_handlers *h, upb_selector_t sel) {
 static void asmlabel(jitcompiler *jc, const char *fmt, ...) {
 #ifndef NDEBUG
   int ofs = jc->dynasm->section->ofs;
-  assert(ofs != jc->lastlabelofs);
+  UPB_ASSERT(ofs != jc->lastlabelofs);
   jc->lastlabelofs = ofs;
 #endif
 
@@ -370,7 +370,7 @@ static bool alwaysok(const upb_handlers *h, upb_selector_t sel) {
   bool ok = upb_handlers_getattr(h, sel, &attr);
   bool ret;
 
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   ret = upb_handlerattr_alwaysok(&attr);
   upb_handlerattr_uninit(&attr);
   return ret;
@@ -964,7 +964,7 @@ static void jitprimitive(jitcompiler *jc, opcode op,
         case UPB_TYPE_STRING:
         case UPB_TYPE_BYTES:
         case UPB_TYPE_MESSAGE:
-          assert(false); break;
+          UPB_ASSERT(false); break;
       }
       /*|  sethas CLOSURE, data->hasbit */
        if (data->hasbit >= 0) {
@@ -1188,7 +1188,7 @@ static void jitdispatch(jitcompiler *jc,
     /*|  // This key will never be in the array part, so do a hash lookup. */
     dasm_put(Dst, 2035, UPB_MAX_FIELDNUMBER);
 # 793 "upb/pb/compile_decoder_x64.dasc"
-    assert(has_hash_entries);
+    UPB_ASSERT(has_hash_entries);
     /*|  ld64  dispatch */
      {
      uintptr_t v = (uintptr_t)dispatch;
@@ -1240,7 +1240,7 @@ static void jittag(jitcompiler *jc, uint64_t tag, int n, int ofs,
   uint32_t *delimend = (jc->pc - 1) + last_arg;
   const size_t ptr_words = sizeof(void*) / sizeof(uint32_t);
 
-  assert((last_instruction & 0xff) == OP_CHECKDELIM);
+  UPB_ASSERT((last_instruction & 0xff) == OP_CHECKDELIM);
 
   if (getop(*(jc->pc - 1)) == OP_TAGN) {
     jc->pc += ptr_words;
@@ -1715,7 +1715,7 @@ static void jitbytecode(jitcompiler *jc) {
 # 1132 "upb/pb/compile_decoder_x64.dasc"
       break;
     case OP_HALT:
-      assert(false);
+      UPB_ASSERT(false);
     }
   }
 
diff --git a/upb/pb/decoder.c b/upb/pb/decoder.c
index 8f4c867dd5..182ecc9d15 100644
--- a/upb/pb/decoder.c
+++ b/upb/pb/decoder.c
@@ -117,7 +117,7 @@ void upb_pbdecoder_seterr(upb_pbdecoder *d, const char *msg) {
 /* How many bytes can be safely read from d->ptr without reading past end-of-buf
  * or past the current delimited end. */
 static size_t curbufleft(const upb_pbdecoder *d) {
-  assert(d->data_end >= d->ptr);
+  UPB_ASSERT(d->data_end >= d->ptr);
   return d->data_end - d->ptr;
 }
 
@@ -138,7 +138,7 @@ size_t delim_remaining(const upb_pbdecoder *d) {
 
 /* Advances d->ptr. */
 static void advance(upb_pbdecoder *d, size_t len) {
-  assert(curbufleft(d) >= len);
+  UPB_ASSERT(curbufleft(d) >= len);
   d->ptr += len;
 }
 
@@ -171,7 +171,7 @@ static void switchtobuf(upb_pbdecoder *d, const char *buf, const char *end) {
 }
 
 static void advancetobuf(upb_pbdecoder *d, const char *buf, size_t len) {
-  assert(curbufleft(d) == 0);
+  UPB_ASSERT(curbufleft(d) == 0);
   d->bufstart_ofs += (d->end - d->buf);
   switchtobuf(d, buf, buf + len);
 }
@@ -180,7 +180,7 @@ static void checkpoint(upb_pbdecoder *d) {
   /* The assertion here is in the interests of efficiency, not correctness.
    * We are trying to ensure that we don't checkpoint() more often than
    * necessary. */
-  assert(d->checkpoint != d->ptr);
+  UPB_ASSERT(d->checkpoint != d->ptr);
   d->checkpoint = d->ptr;
 }
 
@@ -191,8 +191,8 @@ static void checkpoint(upb_pbdecoder *d) {
  * won't actually be read.
  */
 static int32_t skip(upb_pbdecoder *d, size_t bytes) {
-  assert(!in_residual_buf(d, d->ptr) || d->size_param == 0);
-  assert(d->skip == 0);
+  UPB_ASSERT(!in_residual_buf(d, d->ptr) || d->size_param == 0);
+  UPB_ASSERT(d->skip == 0);
   if (bytes > delim_remaining(d)) {
     seterr(d, "Skipped value extended beyond enclosing submessage.");
     return upb_pbdecoder_suspend(d);
@@ -220,7 +220,7 @@ int32_t upb_pbdecoder_resume(upb_pbdecoder *d, void *p, const char *buf,
 
   /* d->skip and d->residual_end could probably elegantly be represented
    * as a single variable, to more easily represent this invariant. */
-  assert(!(d->skip && d->residual_end > d->residual));
+  UPB_ASSERT(!(d->skip && d->residual_end > d->residual));
 
   /* We need to remember the original size_param, so that the value we return
    * is relative to it, even if we do some skipping first. */
@@ -253,7 +253,7 @@ int32_t upb_pbdecoder_resume(upb_pbdecoder *d, void *p, const char *buf,
 
   if (d->residual_end > d->residual) {
     /* We have residual bytes from the last buffer. */
-    assert(d->ptr == d->residual);
+    UPB_ASSERT(d->ptr == d->residual);
   } else {
     switchtobuf(d, buf, buf + size);
   }
@@ -287,8 +287,8 @@ size_t upb_pbdecoder_suspend(upb_pbdecoder *d) {
     return 0;
   } else {
     size_t ret = d->size_param - (d->end - d->checkpoint);
-    assert(!in_residual_buf(d, d->checkpoint));
-    assert(d->buf == d->buf_param || d->buf == &dummy_char);
+    UPB_ASSERT(!in_residual_buf(d, d->checkpoint));
+    UPB_ASSERT(d->buf == d->buf_param || d->buf == &dummy_char);
 
     d->bufstart_ofs += (d->checkpoint - d->buf);
     d->residual_end = d->residual;
@@ -308,7 +308,7 @@ static size_t suspend_save(upb_pbdecoder *d) {
 
   if (d->checkpoint == d->residual) {
     /* Checkpoint was in residual buf; append user byte(s) to residual buf. */
-    assert((d->residual_end - d->residual) + d->size_param <=
+    UPB_ASSERT((d->residual_end - d->residual) + d->size_param <=
            sizeof(d->residual));
     if (!in_residual_buf(d, d->ptr)) {
       d->bufstart_ofs -= (d->residual_end - d->residual);
@@ -318,11 +318,11 @@ static size_t suspend_save(upb_pbdecoder *d) {
   } else {
     /* Checkpoint was in user buf; old residual bytes not needed. */
     size_t save;
-    assert(!in_residual_buf(d, d->checkpoint));
+    UPB_ASSERT(!in_residual_buf(d, d->checkpoint));
 
     d->ptr = d->checkpoint;
     save = curbufleft(d);
-    assert(save <= sizeof(d->residual));
+    UPB_ASSERT(save <= sizeof(d->residual));
     memcpy(d->residual, d->ptr, save);
     d->residual_end = d->residual + save;
     d->bufstart_ofs = offset(d);
@@ -336,7 +336,7 @@ static size_t suspend_save(upb_pbdecoder *d) {
  * Requires that this many bytes are available in the current buffer. */
 UPB_FORCEINLINE static void consumebytes(upb_pbdecoder *d, void *buf,
                                          size_t bytes) {
-  assert(bytes <= curbufleft(d));
+  UPB_ASSERT(bytes <= curbufleft(d));
   memcpy(buf, d->ptr, bytes);
   advance(d, bytes);
 }
@@ -349,7 +349,7 @@ UPB_NOINLINE static int32_t getbytes_slow(upb_pbdecoder *d, void *buf,
   const size_t avail = curbufleft(d);
   consumebytes(d, buf, avail);
   bytes -= avail;
-  assert(bytes > 0);
+  UPB_ASSERT(bytes > 0);
   if (in_residual_buf(d, d->ptr)) {
     advancetobuf(d, d->buf_param, d->size_param);
   }
@@ -532,7 +532,7 @@ UPB_NOINLINE int32_t upb_pbdecoder_checktag_slow(upb_pbdecoder *d,
   if (read == bytes && data == expected) {
     /* Advance past matched bytes. */
     int32_t ok = getbytes(d, &data, read);
-    UPB_ASSERT_VAR(ok, ok < 0);
+    UPB_ASSERT(ok < 0);
     return DECODE_OK;
   } else if (read < bytes && memcmp(&data, &expected, read) == 0) {
     return suspend_save(d);
@@ -607,7 +607,7 @@ have_tag:
 static void goto_endmsg(upb_pbdecoder *d) {
   upb_value v;
   bool found = upb_inttable_lookup32(d->top->dispatch, DISPATCH_ENDMSG, &v);
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   d->pc = d->top->base + upb_value_getuint64(v);
 }
 
@@ -641,7 +641,7 @@ static int32_t dispatch(upb_pbdecoder *d) {
     } else if (wire_type == ((v >> 8) & 0xff)) {
       bool found =
           upb_inttable_lookup(dispatch, fieldnum + UPB_MAX_FIELDNUMBER, &val);
-      UPB_ASSERT_VAR(found, found);
+      UPB_ASSERT(found);
       d->pc = d->top->base + upb_value_getuint64(val);
       return DECODE_OK;
     }
@@ -653,7 +653,7 @@ static int32_t dispatch(upb_pbdecoder *d) {
    * can re-check the delimited end. */
   d->last--;  /* Necessary if we get suspended */
   d->pc = d->last;
-  assert(getop(*d->last) == OP_CHECKDELIM);
+  UPB_ASSERT(getop(*d->last) == OP_CHECKDELIM);
 
   /* Unknown field or ENDGROUP. */
   retval = upb_pbdecoder_skipunknown(d, fieldnum, wire_type);
@@ -671,7 +671,7 @@ static int32_t dispatch(upb_pbdecoder *d) {
 /* Callers know that the stack is more than one deep because the opcodes that
  * call this only occur after PUSH operations. */
 upb_pbdecoder_frame *outer_frame(upb_pbdecoder *d) {
-  assert(d->top != d->stack);
+  UPB_ASSERT(d->top != d->stack);
   return d->top - 1;
 }
 
@@ -703,7 +703,7 @@ size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
     op = getop(instruction);
     arg = instruction >> 8;
     longofs = arg;
-    assert(d->ptr != d->residual_end);
+    UPB_ASSERT(d->ptr != d->residual_end);
     UPB_UNUSED(group);
 #ifdef UPB_DUMP_BYTECODE
     fprintf(stderr, "s_ofs=%d buf_ofs=%d data_rem=%d buf_rem=%d delim_rem=%d "
@@ -778,7 +778,7 @@ size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
           } else {
             int32_t ret = skip(d, n);
             /* This shouldn't return DECODE_OK, because n > len. */
-            assert(ret >= 0);
+            UPB_ASSERT(ret >= 0);
             return ret;
           }
         }
@@ -800,7 +800,7 @@ size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
         d->top->groupnum = *d->pc++;
       )
       VMCASE(OP_POP,
-        assert(d->top > d->stack);
+        UPB_ASSERT(d->top > d->stack);
         decoder_pop(d);
       )
       VMCASE(OP_PUSHLENDELIM,
@@ -816,7 +816,7 @@ size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
         /* We are guaranteed of this assert because we never allow ourselves to
          * consume bytes beyond data_end, which covers delim_end when non-NULL.
          */
-        assert(!(d->delim_end && d->ptr > d->delim_end));
+        UPB_ASSERT(!(d->delim_end && d->ptr > d->delim_end));
         if (d->ptr == d->delim_end)
           d->pc += longofs;
       )
@@ -825,7 +825,7 @@ size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
         d->pc += longofs;
       )
       VMCASE(OP_RET,
-        assert(d->call_len > 0);
+        UPB_ASSERT(d->call_len > 0);
         d->pc = d->callstack[--d->call_len];
       )
       VMCASE(OP_BRANCH,
@@ -952,7 +952,7 @@ bool upb_pbdecoder_end(void *closure, const void *handler_data) {
     if (p != method->code_base.ptr) p--;
     if (getop(*p) == OP_CHECKDELIM) {
       /* Rewind from OP_TAG* to OP_CHECKDELIM. */
-      assert(getop(*d->pc) == OP_TAG1 ||
+      UPB_ASSERT(getop(*d->pc) == OP_TAG1 ||
              getop(*d->pc) == OP_TAG2 ||
              getop(*d->pc) == OP_TAGN ||
              getop(*d->pc) == OP_DISPATCH);
@@ -1016,7 +1016,7 @@ upb_pbdecoder *upb_pbdecoder_create(upb_env *e, const upb_pbdecodermethod *m,
   upb_pbdecoder_reset(d);
   upb_bytessink_reset(&d->input_, &m->input_handler_, d);
 
-  assert(sink);
+  UPB_ASSERT(sink);
   if (d->method_->dest_handlers_) {
     if (sink->handlers != d->method_->dest_handlers_)
       return NULL;
@@ -1024,7 +1024,8 @@ upb_pbdecoder *upb_pbdecoder_create(upb_env *e, const upb_pbdecodermethod *m,
   upb_sink_reset(&d->top->sink, sink->handlers, sink->closure);
 
   /* If this fails, increase the value in decoder.h. */
-  assert(upb_env_bytesallocated(e) - size_before <= UPB_PB_DECODER_SIZE);
+  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(e) - size_before <=
+                      UPB_PB_DECODER_SIZE);
   return d;
 }
 
@@ -1045,7 +1046,7 @@ size_t upb_pbdecoder_maxnesting(const upb_pbdecoder *d) {
 }
 
 bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max) {
-  assert(d->top >= d->stack);
+  UPB_ASSERT(d->top >= d->stack);
 
   if (max < (size_t)(d->top - d->stack)) {
     /* Can't set a limit smaller than what we are currently at. */
diff --git a/upb/pb/encoder.c b/upb/pb/encoder.c
index 8f974a336c..780425db8a 100644
--- a/upb/pb/encoder.c
+++ b/upb/pb/encoder.c
@@ -128,7 +128,7 @@ struct upb_pb_encoder {
 /* TODO(haberman): handle pushback */
 static void putbuf(upb_pb_encoder *e, const char *buf, size_t len) {
   size_t n = upb_bytessink_putbuf(e->output_, e->subc, buf, len, NULL);
-  UPB_ASSERT_VAR(n, n == len);
+  UPB_ASSERT(n == len);
 }
 
 static upb_pb_encoder_segment *top(upb_pb_encoder *e) {
@@ -168,7 +168,7 @@ static bool reserve(upb_pb_encoder *e, size_t bytes) {
 /* Call when "bytes" bytes have been writte at e->ptr.  The caller *must* have
  * previously called reserve() with at least this many bytes. */
 static void encoder_advance(upb_pb_encoder *e, size_t bytes) {
-  assert((size_t)(e->limit - e->ptr) >= bytes);
+  UPB_ASSERT((size_t)(e->limit - e->ptr) >= bytes);
   e->ptr += bytes;
 }
 
@@ -203,7 +203,7 @@ static bool encode_bytes(upb_pb_encoder *e, const void *data, size_t len) {
  * length. */
 static void accumulate(upb_pb_encoder *e) {
   size_t run_len;
-  assert(e->ptr >= e->runbegin);
+  UPB_ASSERT(e->ptr >= e->runbegin);
   run_len = e->ptr - e->runbegin;
   e->segptr->seglen += run_len;
   top(e)->msglen += run_len;
@@ -558,7 +558,8 @@ upb_pb_encoder *upb_pb_encoder_create(upb_env *env, const upb_handlers *h,
   e->ptr = e->buf;
 
   /* If this fails, increase the value in encoder.h. */
-  assert(upb_env_bytesallocated(env) - size_before <= UPB_PB_ENCODER_SIZE);
+  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(env) - size_before <=
+                      UPB_PB_ENCODER_SIZE);
   return e;
 }
 
diff --git a/upb/pb/textprinter.c b/upb/pb/textprinter.c
index b9ff8d4106..abfc2ebee5 100644
--- a/upb/pb/textprinter.c
+++ b/upb/pb/textprinter.c
@@ -112,7 +112,7 @@ bool putf(upb_textprinter *p, const char *fmt, ...) {
   if (!str) return false;
   written = vsprintf(str, fmt, args);
   va_end(args);
-  UPB_ASSERT_VAR(written, written == len);
+  UPB_ASSERT(written == len);
 
   ok = upb_bytessink_putbuf(p->output_, p->subc, str, len, NULL);
   upb_gfree(str);
diff --git a/upb/pb/varint.int.h b/upb/pb/varint.int.h
index 735bcbe21e..c8d4929711 100644
--- a/upb/pb/varint.int.h
+++ b/upb/pb/varint.int.h
@@ -154,9 +154,9 @@ UPB_INLINE uint64_t upb_vencode32(uint32_t val) {
   char buf[UPB_PB_VARINT_MAX_LEN];
   size_t bytes = upb_vencode64(val, buf);
   uint64_t ret = 0;
-  assert(bytes <= 5);
+  UPB_ASSERT(bytes <= 5);
   memcpy(&ret, buf, bytes);
-  assert(ret <= 0xffffffffffU);
+  UPB_ASSERT(ret <= 0xffffffffffU);
   return ret;
 }
 
diff --git a/upb/refcounted.c b/upb/refcounted.c
index ce06708937..f00dbb7d15 100644
--- a/upb/refcounted.c
+++ b/upb/refcounted.c
@@ -134,7 +134,7 @@ static trackedref *trackedref_new(bool is_ref2) {
 static void track(const upb_refcounted *r, const void *owner, bool ref2) {
   upb_value v;
 
-  assert(owner);
+  UPB_ASSERT(owner);
   if (owner == UPB_UNTRACKED_REF) return;
 
   upb_lock();
@@ -145,8 +145,8 @@ static void track(const upb_refcounted *r, const void *owner, bool ref2) {
      * tracking behavior we get with regular refs.  Since ref2s only happen
      * inside upb, we'll accept this limitation until/unless there is a really
      * difficult upb-internal bug that can't be figured out without it. */
-    assert(ref2);
-    assert(ref->is_ref2);
+    UPB_ASSERT(ref2);
+    UPB_ASSERT(ref->is_ref2);
     ref->count++;
   } else {
     trackedref *ref = trackedref_new(ref2);
@@ -156,7 +156,7 @@ static void track(const upb_refcounted *r, const void *owner, bool ref2) {
       /* We know this cast is safe when it is a ref2, because it's coming from
        * another refcounted object. */
       const upb_refcounted *from = owner;
-      assert(!upb_inttable_lookupptr(from->ref2s, r, NULL));
+      UPB_ASSERT(!upb_inttable_lookupptr(from->ref2s, r, NULL));
       upb_inttable_insertptr2(from->ref2s, r, upb_value_ptr(NULL),
                               &upb_alloc_debugrefs);
     }
@@ -169,15 +169,15 @@ static void untrack(const upb_refcounted *r, const void *owner, bool ref2) {
   bool found;
   trackedref *ref;
 
-  assert(owner);
+  UPB_ASSERT(owner);
   if (owner == UPB_UNTRACKED_REF) return;
 
   upb_lock();
   found = upb_inttable_lookupptr(r->refs, owner, &v);
   /* This assert will fail if an owner attempts to release a ref it didn't have. */
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   ref = upb_value_getptr(v);
-  assert(ref->is_ref2 == ref2);
+  UPB_ASSERT(ref->is_ref2 == ref2);
   if (--ref->count == 0) {
     free(ref);
     upb_inttable_removeptr(r->refs, owner, NULL);
@@ -186,7 +186,7 @@ static void untrack(const upb_refcounted *r, const void *owner, bool ref2) {
        * another refcounted object. */
       const upb_refcounted *from = owner;
       bool removed = upb_inttable_removeptr(from->ref2s, r, NULL);
-      assert(removed);
+      UPB_ASSERT(removed);
     }
   }
   upb_unlock();
@@ -199,9 +199,9 @@ static void checkref(const upb_refcounted *r, const void *owner, bool ref2) {
 
   upb_lock();
   found = upb_inttable_lookupptr(r->refs, owner, &v);
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   ref = upb_value_getptr(v);
-  assert(ref->is_ref2 == ref2);
+  UPB_ASSERT(ref->is_ref2 == ref2);
   upb_unlock();
 }
 
@@ -222,7 +222,7 @@ static void getref2s(const upb_refcounted *owner, upb_inttable *tab) {
 
     /* To get the count we need to look in the target's table. */
     found = upb_inttable_lookupptr(to->refs, owner, &v);
-    assert(found);
+    UPB_ASSERT(found);
     ref = upb_value_getptr(v);
     count = upb_value_int32(ref->count);
 
@@ -244,12 +244,12 @@ static void visit_check(const upb_refcounted *obj, const upb_refcounted *subobj,
   bool removed;
   int32_t newcount;
 
-  assert(obj == s->obj);
-  assert(subobj);
+  UPB_ASSERT(obj == s->obj);
+  UPB_ASSERT(subobj);
   removed = upb_inttable_removeptr(ref2, subobj, &v);
   /* The following assertion will fail if the visit() function visits a subobj
    * that it did not have a ref2 on, or visits the same subobj too many times. */
-  assert(removed);
+  UPB_ASSERT(removed);
   newcount = upb_value_getint32(v) - 1;
   if (newcount > 0) {
     upb_inttable_insert2(ref2, (uintptr_t)subobj, upb_value_int32(newcount),
@@ -271,7 +271,7 @@ static void visit(const upb_refcounted *r, upb_refcounted_visit *v,
   if (r->vtbl->visit) r->vtbl->visit(r, visit_check, &state);
 
   /* This assertion will fail if the visit() function missed any children. */
-  assert(upb_inttable_count(&state.ref2) == 0);
+  UPB_ASSERT(upb_inttable_count(&state.ref2) == 0);
   upb_inttable_uninit2(&state.ref2, &upb_alloc_debugrefs);
   if (r->vtbl->visit) r->vtbl->visit(r, v, closure);
 }
@@ -378,7 +378,7 @@ static uint64_t trygetattr(const tarjan *t, const upb_refcounted *r) {
 static uint64_t getattr(const tarjan *t, const upb_refcounted *r) {
   upb_value v;
   bool found = upb_inttable_lookupptr(&t->objattr, r, &v);
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   return upb_value_getuint64(v);
 }
 
@@ -392,13 +392,13 @@ static color_t color(tarjan *t, const upb_refcounted *r) {
 }
 
 static void set_gray(tarjan *t, const upb_refcounted *r) {
-  assert(color(t, r) == BLACK);
+  UPB_ASSERT(color(t, r) == BLACK);
   setattr(t, r, GRAY);
 }
 
 /* Pushes an obj onto the Tarjan stack and sets it to GREEN. */
 static void push(tarjan *t, const upb_refcounted *r) {
-  assert(color(t, r) == BLACK || color(t, r) == GRAY);
+  UPB_ASSERT(color(t, r) == BLACK || color(t, r) == GRAY);
   /* This defines the attr layout for the GREEN state.  "index" and "lowlink"
    * get 31 bits, which is plenty (limit of 2B objects frozen at a time). */
   setattr(t, r, GREEN | (t->index << 2) | (t->index << 33));
@@ -413,7 +413,7 @@ static void push(tarjan *t, const upb_refcounted *r) {
  * SCC group. */
 static upb_refcounted *pop(tarjan *t) {
   upb_refcounted *r = upb_value_getptr(upb_inttable_pop(&t->stack));
-  assert(color(t, r) == GREEN);
+  UPB_ASSERT(color(t, r) == GREEN);
   /* This defines the attr layout for nodes in the WHITE state.
    * Top of group stack is [group, NULL]; we point at group. */
   setattr(t, r, WHITE | (upb_inttable_count(&t->groups) - 2) << 8);
@@ -433,7 +433,7 @@ static void tarjan_newgroup(tarjan *t) {
 }
 
 static uint32_t idx(tarjan *t, const upb_refcounted *r) {
-  assert(color(t, r) == GREEN);
+  UPB_ASSERT(color(t, r) == GREEN);
   return (getattr(t, r) >> 2) & 0x7FFFFFFF;
 }
 
@@ -446,7 +446,7 @@ static uint32_t lowlink(tarjan *t, const upb_refcounted *r) {
 }
 
 static void set_lowlink(tarjan *t, const upb_refcounted *r, uint32_t lowlink) {
-  assert(color(t, r) == GREEN);
+  UPB_ASSERT(color(t, r) == GREEN);
   setattr(t, r, ((uint64_t)lowlink << 33) | (getattr(t, r) & 0x1FFFFFFFF));
 }
 
@@ -455,10 +455,10 @@ static uint32_t *group(tarjan *t, upb_refcounted *r) {
   upb_value v;
   bool found;
 
-  assert(color(t, r) == WHITE);
+  UPB_ASSERT(color(t, r) == WHITE);
   groupnum = getattr(t, r) >> 8;
   found = upb_inttable_lookup(&t->groups, groupnum, &v);
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   return upb_value_getptr(v);
 }
 
@@ -469,10 +469,10 @@ static upb_refcounted *groupleader(tarjan *t, upb_refcounted *r) {
   upb_value v;
   bool found;
 
-  assert(color(t, r) == WHITE);
+  UPB_ASSERT(color(t, r) == WHITE);
   leader_slot = (getattr(t, r) >> 8) + 1;
   found = upb_inttable_lookup(&t->groups, leader_slot, &v);
-  UPB_ASSERT_VAR(found, found);
+  UPB_ASSERT(found);
   if (upb_value_getptr(v)) {
     return upb_value_getptr(v);
   } else {
@@ -532,7 +532,7 @@ static void do_tarjan(const upb_refcounted *obj, tarjan *t) {
 static void crossref(const upb_refcounted *r, const upb_refcounted *subobj,
                      void *_t) {
   tarjan *t = _t;
-  assert(color(t, r) > BLACK);
+  UPB_ASSERT(color(t, r) > BLACK);
   if (color(t, subobj) > BLACK && r->group != subobj->group) {
     /* Previously this ref was not reflected in subobj->group because they
      * were in the same group; now that they are split a ref must be taken. */
@@ -600,13 +600,13 @@ static bool freeze(upb_refcounted *const*roots, int n, upb_status *s,
       upb_refcounted *move = obj->next;
       if (obj == move) {
         /* Removing the last object from a group. */
-        assert(*obj->group == obj->individual_count);
+        UPB_ASSERT(*obj->group == obj->individual_count);
         upb_gfree(obj->group);
       } else {
         obj->next = move->next;
         /* This may decrease to zero; we'll collect GRAY objects (if any) that
          * remain in the group in the third pass. */
-        assert(*move->group >= move->individual_count);
+        UPB_ASSERT(*move->group >= move->individual_count);
         *move->group -= move->individual_count;
       }
 
@@ -619,7 +619,7 @@ static bool freeze(upb_refcounted *const*roots, int n, upb_status *s,
         *move->group = move->individual_count;
       } else {
         /* Group already has at least one object in it. */
-        assert(leader->group == group(&t, move));
+        UPB_ASSERT(leader->group == group(&t, move));
         move->group = group(&t, move);
         move->next = leader->next;
         leader->next = move;
@@ -726,7 +726,7 @@ static void release_ref2(const upb_refcounted *obj,
   UPB_UNUSED(closure);
   untrack(subobj, obj, true);
   if (!merged(obj, subobj)) {
-    assert(subobj->is_frozen);
+    UPB_ASSERT(subobj->is_frozen);
     unref(subobj);
   }
 }
@@ -745,7 +745,7 @@ static void unref(const upb_refcounted *r) {
     o = r;
     do {
       const upb_refcounted *next = o->next;
-      assert(o->is_frozen || o->individual_count == 0);
+      UPB_ASSERT(o->is_frozen || o->individual_count == 0);
       freeobj((upb_refcounted*)o);
       o = next;
     } while(o != r);
@@ -769,9 +769,9 @@ bool upb_refcounted_init(upb_refcounted *r,
    * basically every program using upb. */
   const int x = 1;
 #ifdef UPB_BIG_ENDIAN
-  assert(*(char*)&x != 1);
+  UPB_ASSERT(*(char*)&x != 1);
 #else
-  assert(*(char*)&x == 1);
+  UPB_ASSERT(*(char*)&x == 1);
 #endif
 #endif
 
@@ -806,7 +806,7 @@ void upb_refcounted_unref(const upb_refcounted *r, const void *owner) {
 }
 
 void upb_refcounted_ref2(const upb_refcounted *r, upb_refcounted *from) {
-  assert(!from->is_frozen);  /* Non-const pointer implies this. */
+  UPB_ASSERT(!from->is_frozen);  /* Non-const pointer implies this. */
   track(r, from, true);
   if (r->is_frozen) {
     refgroup(r->group);
@@ -816,18 +816,18 @@ void upb_refcounted_ref2(const upb_refcounted *r, upb_refcounted *from) {
 }
 
 void upb_refcounted_unref2(const upb_refcounted *r, upb_refcounted *from) {
-  assert(!from->is_frozen);  /* Non-const pointer implies this. */
+  UPB_ASSERT(!from->is_frozen);  /* Non-const pointer implies this. */
   untrack(r, from, true);
   if (r->is_frozen) {
     unref(r);
   } else {
-    assert(merged(r, from));
+    UPB_ASSERT(merged(r, from));
   }
 }
 
 void upb_refcounted_donateref(
     const upb_refcounted *r, const void *from, const void *to) {
-  assert(from != to);
+  UPB_ASSERT(from != to);
   if (to != NULL)
     upb_refcounted_ref(r, to);
   if (from != NULL)
@@ -843,9 +843,9 @@ bool upb_refcounted_freeze(upb_refcounted *const*roots, int n, upb_status *s,
   int i;
   bool ret;
   for (i = 0; i < n; i++) {
-    assert(!roots[i]->is_frozen);
+    UPB_ASSERT(!roots[i]->is_frozen);
   }
   ret = freeze(roots, n, s, maxdepth);
-  assert(!s || ret == upb_ok(s));
+  UPB_ASSERT(!s || ret == upb_ok(s));
   return ret;
 }
diff --git a/upb/refcounted.h b/upb/refcounted.h
index 115fc43a9d..6698d38df7 100644
--- a/upb/refcounted.h
+++ b/upb/refcounted.h
@@ -258,7 +258,7 @@ template <class T> class upb::reffed_ptr {
   reffed_ptr(U* val, const void* ref_donor = NULL)
       : ptr_(upb::upcast(val)) {
     if (ref_donor) {
-      assert(ptr_);
+      UPB_ASSERT(ptr_);
       ptr_->DonateRef(ref_donor, this);
     } else if (ptr_) {
       ptr_->Ref(this);
@@ -303,12 +303,12 @@ template <class T> class upb::reffed_ptr {
   }
 
   T& operator*() const {
-    assert(ptr_);
+    UPB_ASSERT(ptr_);
     return *ptr_;
   }
 
   T* operator->() const {
-    assert(ptr_);
+    UPB_ASSERT(ptr_);
     return ptr_;
   }
 
diff --git a/upb/shim/shim.c b/upb/shim/shim.c
index b8a43f560c..1429332a50 100644
--- a/upb/shim/shim.c
+++ b/upb/shim/shim.c
@@ -50,7 +50,7 @@ bool upb_shim_set(upb_handlers *h, const upb_fielddef *f, size_t offset,
     TYPE(DOUBLE, double);
     TYPE(FLOAT,  float);
     TYPE(BOOL,   bool);
-    default: assert(false); break;
+    default: UPB_ASSERT(false); break;
   }
 #undef TYPE
 
diff --git a/upb/symtab.c b/upb/symtab.c
index 8b9e449444..7d1aa76dc2 100644
--- a/upb/symtab.c
+++ b/upb/symtab.c
@@ -33,13 +33,13 @@ void upb_symtab_freeze(upb_symtab *s) {
   upb_refcounted *r;
   bool ok;
 
-  assert(!upb_symtab_isfrozen(s));
+  UPB_ASSERT(!upb_symtab_isfrozen(s));
   r = upb_symtab_upcast_mutable(s);
   /* The symtab does not take ref2's (see refcounted.h) on the defs, because
    * defs cannot refer back to the table and therefore cannot create cycles.  So
    * 0 will suffice for maxdepth here. */
   ok = upb_refcounted_freeze(&r, 1, NULL, 0);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
 }
 
 const upb_def *upb_symtab_lookup(const upb_symtab *s, const char *sym) {
@@ -77,7 +77,7 @@ static upb_def *upb_resolvename(const upb_strtable *t,
     /* Remove components from base until we find an entry or run out.
      * TODO: This branch is totally broken, but currently not used. */
     (void)base;
-    assert(false);
+    UPB_ASSERT(false);
     return NULL;
   }
 }
@@ -139,7 +139,7 @@ static bool upb_resolve_dfs(const upb_def *def, upb_strtable *addtab,
     upb_value v;
     const upb_msgdef *m;
 
-    assert(upb_def_isfrozen(def));
+    UPB_ASSERT(upb_def_isfrozen(def));
     if (def->type == UPB_DEF_FIELD) continue;
     if (upb_strtable_lookup(addtab, upb_def_fullname(def), &v)) {
       need_dup = true;
@@ -214,7 +214,7 @@ static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
     return true;
   }
 
-  assert(!upb_symtab_isfrozen(s));
+  UPB_ASSERT(!upb_symtab_isfrozen(s));
   if (!upb_strtable_init(&addtab, UPB_CTYPE_PTR)) {
     upb_status_seterrmsg(status, "out of memory");
     return false;
@@ -230,7 +230,7 @@ static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
       upb_status_seterrmsg(status, "added defs must be mutable");
       goto err;
     }
-    assert(!upb_def_isfrozen(def));
+    UPB_ASSERT(!upb_def_isfrozen(def));
     fullname = upb_def_fullname(def);
     if (!fullname) {
       upb_status_seterrmsg(
@@ -274,7 +274,7 @@ static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
     if (!f) continue;
     msgname = upb_fielddef_containingtypename(f);
     /* We validated this earlier in this function. */
-    assert(msgname);
+    UPB_ASSERT(msgname);
 
     /* If the extendee name is absolutely qualified, move past the initial ".".
      * TODO(haberman): it is not obvious what it would mean if this was not
@@ -405,7 +405,7 @@ static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
       upb_def_unref(def, s);
     }
     success = upb_strtable_insert(&s->symtab, name, upb_value_ptr(def));
-    UPB_ASSERT_VAR(success, success == true);
+    UPB_ASSERT(success == true);
   }
   upb_gfree(add_defs);
   return true;
@@ -429,7 +429,7 @@ err: {
   }
   upb_strtable_uninit(&addtab);
   upb_gfree(add_defs);
-  assert(!upb_ok(status));
+  UPB_ASSERT(!upb_ok(status));
   return false;
 }
 
diff --git a/upb/table.c b/upb/table.c
index 53f757e325..286e08ff50 100644
--- a/upb/table.c
+++ b/upb/table.c
@@ -14,16 +14,11 @@
 #define ARRAY_SIZE(x) \
     ((sizeof(x)/sizeof(0[x])) / ((size_t)(!(sizeof(x) % sizeof(0[x])))))
 
-#ifdef NDEBUG
 static void upb_check_alloc(upb_table *t, upb_alloc *a) {
   UPB_UNUSED(t);
   UPB_UNUSED(a);
+  UPB_ASSERT_DEBUGVAR(t->alloc == a);
 }
-#else
-static void upb_check_alloc(upb_table *t, upb_alloc *a) {
-  assert(t->alloc == a);
-}
-#endif
 
 static const double MAX_LOAD = 0.85;
 
@@ -132,7 +127,7 @@ static void uninit(upb_table *t, upb_alloc *a) {
 
 static upb_tabent *emptyent(upb_table *t) {
   upb_tabent *e = mutable_entries(t) + upb_table_size(t);
-  while (1) { if (upb_tabent_isempty(--e)) return e; assert(e > t->entries); }
+  while (1) { if (upb_tabent_isempty(--e)) return e; UPB_ASSERT(e > t->entries); }
 }
 
 static upb_tabent *getentry_mutable(upb_table *t, uint32_t hash) {
@@ -177,10 +172,8 @@ static void insert(upb_table *t, lookupkey_t key, upb_tabkey tabkey,
   upb_tabent *mainpos_e;
   upb_tabent *our_e;
 
-  UPB_UNUSED(eql);
-  UPB_UNUSED(key);
-  assert(findentry(t, key, hash, eql) == NULL);
-  assert(val.ctype == t->ctype);
+  UPB_ASSERT(findentry(t, key, hash, eql) == NULL);
+  UPB_ASSERT_DEBUGVAR(val.ctype == t->ctype);
 
   t->count++;
   mainpos_e = getentry_mutable(t, hash);
@@ -207,7 +200,7 @@ static void insert(upb_table *t, lookupkey_t key, upb_tabkey tabkey,
       *new_e = *mainpos_e;  /* copies next. */
       while (chain->next != mainpos_e) {
         chain = (upb_tabent*)chain->next;
-        assert(chain);
+        UPB_ASSERT(chain);
       }
       chain->next = new_e;
       our_e = mainpos_e;
@@ -216,7 +209,7 @@ static void insert(upb_table *t, lookupkey_t key, upb_tabkey tabkey,
   }
   our_e->key = tabkey;
   our_e->val.val = val.val;
-  assert(findentry(t, key, hash, eql) == our_e);
+  UPB_ASSERT(findentry(t, key, hash, eql) == our_e);
 }
 
 static bool rm(upb_table *t, lookupkey_t key, upb_value *val,
@@ -397,19 +390,19 @@ bool upb_strtable_done(const upb_strtable_iter *i) {
 }
 
 const char *upb_strtable_iter_key(const upb_strtable_iter *i) {
-  assert(!upb_strtable_done(i));
+  UPB_ASSERT(!upb_strtable_done(i));
   return upb_tabstr(str_tabent(i)->key, NULL);
 }
 
 size_t upb_strtable_iter_keylength(const upb_strtable_iter *i) {
   uint32_t len;
-  assert(!upb_strtable_done(i));
+  UPB_ASSERT(!upb_strtable_done(i));
   upb_tabstr(str_tabent(i)->key, &len);
   return len;
 }
 
 upb_value upb_strtable_iter_value(const upb_strtable_iter *i) {
-  assert(!upb_strtable_done(i));
+  UPB_ASSERT(!upb_strtable_done(i));
   return _upb_value_val(str_tabent(i)->val.val, i->t->t.ctype);
 }
 
@@ -468,9 +461,9 @@ static void check(upb_inttable *t) {
     upb_inttable_iter i;
     upb_inttable_begin(&i, t);
     for(; !upb_inttable_done(&i); upb_inttable_next(&i), count++) {
-      assert(upb_inttable_lookup(t, upb_inttable_iter_key(&i), NULL));
+      UPB_ASSERT(upb_inttable_lookup(t, upb_inttable_iter_key(&i), NULL));
     }
-    assert(count == upb_inttable_count(t));
+    UPB_ASSERT(count == upb_inttable_count(t));
   }
 #endif
 }
@@ -508,13 +501,12 @@ bool upb_inttable_insert2(upb_inttable *t, uintptr_t key, upb_value val,
                           upb_alloc *a) {
   upb_tabval tabval;
   tabval.val = val.val;
-  UPB_UNUSED(tabval);
-  assert(upb_arrhas(tabval));  /* This will reject (uint64_t)-1.  Fix this. */
+  UPB_ASSERT(upb_arrhas(tabval));  /* This will reject (uint64_t)-1.  Fix this. */
 
   upb_check_alloc(&t->t, a);
 
   if (key < t->array_size) {
-    assert(!upb_arrhas(t->array[key]));
+    UPB_ASSERT(!upb_arrhas(t->array[key]));
     t->array_count++;
     mutable_array(t)[key].val = val.val;
   } else {
@@ -537,7 +529,7 @@ bool upb_inttable_insert2(upb_inttable *t, uintptr_t key, upb_value val,
         insert(&new_table, intkey(e->key), e->key, v, hash, &inthash, &inteql);
       }
 
-      assert(t->t.count == new_table.count);
+      UPB_ASSERT(t->t.count == new_table.count);
 
       uninit(&t->t, a);
       t->t = new_table;
@@ -593,7 +585,7 @@ bool upb_inttable_push2(upb_inttable *t, upb_value val, upb_alloc *a) {
 upb_value upb_inttable_pop(upb_inttable *t) {
   upb_value val;
   bool ok = upb_inttable_remove(t, upb_inttable_count(t) - 1, &val);
-  UPB_ASSERT_VAR(ok, ok);
+  UPB_ASSERT(ok);
   return val;
 }
 
@@ -649,7 +641,7 @@ void upb_inttable_compact2(upb_inttable *t, upb_alloc *a) {
     arr_count -= counts[size_lg2];
   }
 
-  assert(arr_count <= upb_inttable_count(t));
+  UPB_ASSERT(arr_count <= upb_inttable_count(t));
 
   {
     /* Insert all elements into new, perfectly-sized table. */
@@ -664,8 +656,8 @@ void upb_inttable_compact2(upb_inttable *t, upb_alloc *a) {
       uintptr_t k = upb_inttable_iter_key(&i);
       upb_inttable_insert2(&new_t, k, upb_inttable_iter_value(&i), a);
     }
-    assert(new_t.array_size == arr_size);
-    assert(new_t.t.size_lg2 == hashsize_lg2);
+    UPB_ASSERT(new_t.array_size == arr_size);
+    UPB_ASSERT(new_t.t.size_lg2 == hashsize_lg2);
   }
   upb_inttable_uninit2(t, a);
   *t = new_t;
@@ -674,12 +666,12 @@ void upb_inttable_compact2(upb_inttable *t, upb_alloc *a) {
 /* Iteration. */
 
 static const upb_tabent *int_tabent(const upb_inttable_iter *i) {
-  assert(!i->array_part);
+  UPB_ASSERT(!i->array_part);
   return &i->t->t.entries[i->index];
 }
 
 static upb_tabval int_arrent(const upb_inttable_iter *i) {
-  assert(i->array_part);
+  UPB_ASSERT(i->array_part);
   return i->t->array[i->index];
 }
 
@@ -716,12 +708,12 @@ bool upb_inttable_done(const upb_inttable_iter *i) {
 }
 
 uintptr_t upb_inttable_iter_key(const upb_inttable_iter *i) {
-  assert(!upb_inttable_done(i));
+  UPB_ASSERT(!upb_inttable_done(i));
   return i->array_part ? i->index : int_tabent(i)->key;
 }
 
 upb_value upb_inttable_iter_value(const upb_inttable_iter *i) {
-  assert(!upb_inttable_done(i));
+  UPB_ASSERT(!upb_inttable_done(i));
   return _upb_value_val(
       i->array_part ? i->t->array[i->index].val : int_tabent(i)->val.val,
       i->t->t.ctype);
diff --git a/upb/table.int.h b/upb/table.int.h
index 131a74f8de..f0b395a0f1 100644
--- a/upb/table.int.h
+++ b/upb/table.int.h
@@ -20,7 +20,6 @@
 #ifndef UPB_TABLE_H_
 #define UPB_TABLE_H_
 
-#include <assert.h>
 #include <stdint.h>
 #include <string.h>
 #include "upb/upb.h"
@@ -103,7 +102,7 @@ UPB_INLINE upb_value _upb_value_val(uint64_t val, upb_ctype_t ctype) {
     return ret; \
   } \
   UPB_INLINE type_t upb_value_get ## name(upb_value val) { \
-    assert(val.ctype == proto_type); \
+    UPB_ASSERT_DEBUGVAR(val.ctype == proto_type); \
     return (type_t)(converter)val.val; \
   }
 
diff --git a/upb/upb.c b/upb/upb.c
index 8a9c4a7ca5..72e6fdbf31 100644
--- a/upb/upb.c
+++ b/upb/upb.c
@@ -21,7 +21,7 @@ bool upb_dumptostderr(void *closure, const upb_status* status) {
 static void nullz(upb_status *status) {
   const char *ellipsis = "...";
   size_t len = strlen(ellipsis);
-  assert(sizeof(status->msg) > len);
+  UPB_ASSERT(sizeof(status->msg) > len);
   memcpy(status->msg + sizeof(status->msg) - len, ellipsis, len);
 }
 
diff --git a/upb/upb.h b/upb/upb.h
index 1ff47ded1e..6c7a6277b4 100644
--- a/upb/upb.h
+++ b/upb/upb.h
@@ -196,10 +196,17 @@ template <int N> class InlinedEnvironment;
 
 #define UPB_UNUSED(var) (void)var
 
-/* For asserting something about a variable when the variable is not used for
- * anything else.  This prevents "unused variable" warnings when compiling in
- * debug mode. */
-#define UPB_ASSERT_VAR(var, predicate) UPB_UNUSED(var); assert(predicate)
+/* UPB_ASSERT(): in release mode, we use the expression without letting it be
+ * evaluated.  This prevents "unused variable" warnings. */
+#ifdef NDEBUG
+#define UPB_ASSERT(expr) do {} while (false && (expr))
+#else
+#define UPB_ASSERT(expr) assert(expr)
+#endif
+
+/* UPB_ASSERT_DEBUGVAR(): assert that uses functions or variables that only
+ * exist in debug mode.  This turns into regular assert. */
+#define UPB_ASSERT_DEBUGVAR(expr) assert(expr)
 
 /* Generic function type. */
 typedef void upb_func();
@@ -434,13 +441,13 @@ struct upb_alloc {
 };
 
 UPB_INLINE void *upb_malloc(upb_alloc *alloc, size_t size) {
-  assert(size > 0);
+  UPB_ASSERT(size > 0);
   return alloc->func(alloc, NULL, 0, size);
 }
 
 UPB_INLINE void *upb_realloc(upb_alloc *alloc, void *ptr, size_t oldsize,
                              size_t size) {
-  assert(size > 0);
+  UPB_ASSERT(size > 0);
   return alloc->func(alloc, ptr, oldsize, size);
 }