diff --git a/cmake/google/protobuf/descriptor.upb.c b/cmake/google/protobuf/descriptor.upb.c
index fdbf23b9d1..fc0e469819 100644
--- a/cmake/google/protobuf/descriptor.upb.c
+++ b/cmake/google/protobuf/descriptor.upb.c
@@ -17,7 +17,7 @@ static const upb_msglayout_sub google_protobuf_FileDescriptorSet_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_FileDescriptorSet__fields[1] = {
-  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_FileDescriptorSet_msginit = {
@@ -36,18 +36,18 @@ static const upb_msglayout_sub google_protobuf_FileDescriptorProto_submsgs[6] =
 };
 
 static const upb_msglayout_field google_protobuf_FileDescriptorProto__fields[12] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {3, UPB_SIZE(36, 72), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {4, UPB_SIZE(40, 80), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {5, UPB_SIZE(44, 88), 0, 1, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {6, UPB_SIZE(48, 96), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {7, UPB_SIZE(52, 104), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {8, UPB_SIZE(28, 56), 3, 3, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {9, UPB_SIZE(32, 64), 4, 5, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {10, UPB_SIZE(56, 112), 0, 0, 5, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {11, UPB_SIZE(60, 120), 0, 0, 5, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {12, UPB_SIZE(20, 40), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(36, 72), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(40, 80), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(44, 88), 0, 1, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(48, 96), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {7, UPB_SIZE(52, 104), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {8, UPB_SIZE(28, 56), 3, 3, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {9, UPB_SIZE(32, 64), 4, 5, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {10, UPB_SIZE(56, 112), 0, 0, 5, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {11, UPB_SIZE(60, 120), 0, 0, 5, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {12, UPB_SIZE(20, 40), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_FileDescriptorProto_msginit = {
@@ -67,16 +67,16 @@ static const upb_msglayout_sub google_protobuf_DescriptorProto_submsgs[7] = {
 };
 
 static const upb_msglayout_field google_protobuf_DescriptorProto__fields[10] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(16, 32), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {3, UPB_SIZE(20, 40), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {4, UPB_SIZE(24, 48), 0, 3, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {5, UPB_SIZE(28, 56), 0, 1, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {6, UPB_SIZE(32, 64), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {7, UPB_SIZE(12, 24), 2, 5, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {8, UPB_SIZE(36, 72), 0, 6, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {9, UPB_SIZE(40, 80), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {10, UPB_SIZE(44, 88), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(16, 32), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(20, 40), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(24, 48), 0, 3, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(28, 56), 0, 1, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(32, 64), 0, 4, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {7, UPB_SIZE(12, 24), 2, 5, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {8, UPB_SIZE(36, 72), 0, 6, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {9, UPB_SIZE(40, 80), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {10, UPB_SIZE(44, 88), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_DescriptorProto_msginit = {
@@ -90,9 +90,9 @@ static const upb_msglayout_sub google_protobuf_DescriptorProto_ExtensionRange_su
 };
 
 static const upb_msglayout_field google_protobuf_DescriptorProto_ExtensionRange__fields[3] = {
-  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {3, UPB_SIZE(12, 16), 3, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(12, 16), 3, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_DescriptorProto_ExtensionRange_msginit = {
@@ -102,8 +102,8 @@ const upb_msglayout google_protobuf_DescriptorProto_ExtensionRange_msginit = {
 };
 
 static const upb_msglayout_field google_protobuf_DescriptorProto_ReservedRange__fields[2] = {
-  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
+  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_DescriptorProto_ReservedRange_msginit = {
@@ -117,7 +117,7 @@ static const upb_msglayout_sub google_protobuf_ExtensionRangeOptions_submsgs[1]
 };
 
 static const upb_msglayout_field google_protobuf_ExtensionRangeOptions__fields[1] = {
-  {999, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {999, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_ExtensionRangeOptions_msginit = {
@@ -131,17 +131,17 @@ static const upb_msglayout_sub google_protobuf_FieldDescriptorProto_submsgs[1] =
 };
 
 static const upb_msglayout_field google_protobuf_FieldDescriptorProto__fields[11] = {
-  {1, UPB_SIZE(24, 24), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(32, 40), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {3, UPB_SIZE(12, 12), 3, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {4, UPB_SIZE(4, 4), 4, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {5, UPB_SIZE(8, 8), 5, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {6, UPB_SIZE(40, 56), 6, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {7, UPB_SIZE(48, 72), 7, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {8, UPB_SIZE(64, 104), 8, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {9, UPB_SIZE(16, 16), 9, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {10, UPB_SIZE(56, 88), 10, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {17, UPB_SIZE(20, 20), 11, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
+  {1, UPB_SIZE(24, 24), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(32, 40), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(12, 12), 3, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(4, 4), 4, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(8, 8), 5, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(40, 56), 6, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {7, UPB_SIZE(48, 72), 7, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {8, UPB_SIZE(64, 104), 8, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {9, UPB_SIZE(16, 16), 9, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {10, UPB_SIZE(56, 88), 10, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {17, UPB_SIZE(20, 20), 11, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_FieldDescriptorProto_msginit = {
@@ -155,8 +155,8 @@ static const upb_msglayout_sub google_protobuf_OneofDescriptorProto_submsgs[1] =
 };
 
 static const upb_msglayout_field google_protobuf_OneofDescriptorProto__fields[2] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(12, 24), 2, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(12, 24), 2, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_OneofDescriptorProto_msginit = {
@@ -172,11 +172,11 @@ static const upb_msglayout_sub google_protobuf_EnumDescriptorProto_submsgs[3] =
 };
 
 static const upb_msglayout_field google_protobuf_EnumDescriptorProto__fields[5] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(16, 32), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {3, UPB_SIZE(12, 24), 2, 1, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {4, UPB_SIZE(20, 40), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {5, UPB_SIZE(24, 48), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(16, 32), 0, 2, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(12, 24), 2, 1, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(20, 40), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(24, 48), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_EnumDescriptorProto_msginit = {
@@ -186,8 +186,8 @@ const upb_msglayout google_protobuf_EnumDescriptorProto_msginit = {
 };
 
 static const upb_msglayout_field google_protobuf_EnumDescriptorProto_EnumReservedRange__fields[2] = {
-  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
+  {1, UPB_SIZE(4, 4), 1, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(8, 8), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit = {
@@ -201,9 +201,9 @@ static const upb_msglayout_sub google_protobuf_EnumValueDescriptorProto_submsgs[
 };
 
 static const upb_msglayout_field google_protobuf_EnumValueDescriptorProto__fields[3] = {
-  {1, UPB_SIZE(8, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(4, 4), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {3, UPB_SIZE(16, 24), 3, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(8, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(4, 4), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(16, 24), 3, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_EnumValueDescriptorProto_msginit = {
@@ -218,9 +218,9 @@ static const upb_msglayout_sub google_protobuf_ServiceDescriptorProto_submsgs[2]
 };
 
 static const upb_msglayout_field google_protobuf_ServiceDescriptorProto__fields[3] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(16, 32), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {3, UPB_SIZE(12, 24), 2, 1, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(16, 32), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(12, 24), 2, 1, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_ServiceDescriptorProto_msginit = {
@@ -234,12 +234,12 @@ static const upb_msglayout_sub google_protobuf_MethodDescriptorProto_submsgs[1]
 };
 
 static const upb_msglayout_field google_protobuf_MethodDescriptorProto__fields[6] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {3, UPB_SIZE(20, 40), 3, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {4, UPB_SIZE(28, 56), 4, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << 6)},
-  {5, UPB_SIZE(1, 1), 5, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {6, UPB_SIZE(2, 2), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(20, 40), 3, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(28, 56), 4, 0, 11, _UPB_MODE_SCALAR | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(1, 1), 5, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(2, 2), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_MethodDescriptorProto_msginit = {
@@ -253,27 +253,27 @@ static const upb_msglayout_sub google_protobuf_FileOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_FileOptions__fields[21] = {
-  {1, UPB_SIZE(20, 24), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {8, UPB_SIZE(28, 40), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {9, UPB_SIZE(4, 4), 3, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {10, UPB_SIZE(8, 8), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {11, UPB_SIZE(36, 56), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {16, UPB_SIZE(9, 9), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {17, UPB_SIZE(10, 10), 7, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {18, UPB_SIZE(11, 11), 8, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {20, UPB_SIZE(12, 12), 9, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {23, UPB_SIZE(13, 13), 10, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {27, UPB_SIZE(14, 14), 11, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {31, UPB_SIZE(15, 15), 12, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {36, UPB_SIZE(44, 72), 13, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {37, UPB_SIZE(52, 88), 14, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {39, UPB_SIZE(60, 104), 15, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {40, UPB_SIZE(68, 120), 16, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {41, UPB_SIZE(76, 136), 17, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {42, UPB_SIZE(16, 16), 18, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {44, UPB_SIZE(84, 152), 19, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {45, UPB_SIZE(92, 168), 20, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {999, UPB_SIZE(100, 184), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(20, 24), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {8, UPB_SIZE(28, 40), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {9, UPB_SIZE(4, 4), 3, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {10, UPB_SIZE(8, 8), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {11, UPB_SIZE(36, 56), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {16, UPB_SIZE(9, 9), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {17, UPB_SIZE(10, 10), 7, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {18, UPB_SIZE(11, 11), 8, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {20, UPB_SIZE(12, 12), 9, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {23, UPB_SIZE(13, 13), 10, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {27, UPB_SIZE(14, 14), 11, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {31, UPB_SIZE(15, 15), 12, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {36, UPB_SIZE(44, 72), 13, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {37, UPB_SIZE(52, 88), 14, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {39, UPB_SIZE(60, 104), 15, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {40, UPB_SIZE(68, 120), 16, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {41, UPB_SIZE(76, 136), 17, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {42, UPB_SIZE(16, 16), 18, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {44, UPB_SIZE(84, 152), 19, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {45, UPB_SIZE(92, 168), 20, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(100, 184), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_FileOptions_msginit = {
@@ -287,11 +287,11 @@ static const upb_msglayout_sub google_protobuf_MessageOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_MessageOptions__fields[5] = {
-  {1, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {2, UPB_SIZE(2, 2), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {3, UPB_SIZE(3, 3), 3, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {7, UPB_SIZE(4, 4), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {999, UPB_SIZE(8, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(2, 2), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(3, 3), 3, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {7, UPB_SIZE(4, 4), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(8, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_MessageOptions_msginit = {
@@ -305,13 +305,13 @@ static const upb_msglayout_sub google_protobuf_FieldOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_FieldOptions__fields[7] = {
-  {1, UPB_SIZE(4, 4), 1, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {2, UPB_SIZE(12, 12), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {3, UPB_SIZE(13, 13), 3, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {5, UPB_SIZE(14, 14), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {6, UPB_SIZE(8, 8), 5, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {10, UPB_SIZE(15, 15), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {999, UPB_SIZE(16, 16), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(4, 4), 1, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(12, 12), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(13, 13), 3, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(14, 14), 4, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(8, 8), 5, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {10, UPB_SIZE(15, 15), 6, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(16, 16), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_FieldOptions_msginit = {
@@ -325,7 +325,7 @@ static const upb_msglayout_sub google_protobuf_OneofOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_OneofOptions__fields[1] = {
-  {999, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {999, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_OneofOptions_msginit = {
@@ -339,9 +339,9 @@ static const upb_msglayout_sub google_protobuf_EnumOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_EnumOptions__fields[3] = {
-  {2, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {3, UPB_SIZE(2, 2), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {2, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(2, 2), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_EnumOptions_msginit = {
@@ -355,8 +355,8 @@ static const upb_msglayout_sub google_protobuf_EnumValueOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_EnumValueOptions__fields[2] = {
-  {1, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_EnumValueOptions_msginit = {
@@ -370,8 +370,8 @@ static const upb_msglayout_sub google_protobuf_ServiceOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_ServiceOptions__fields[2] = {
-  {33, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {33, UPB_SIZE(1, 1), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(4, 8), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_ServiceOptions_msginit = {
@@ -385,9 +385,9 @@ static const upb_msglayout_sub google_protobuf_MethodOptions_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_MethodOptions__fields[3] = {
-  {33, UPB_SIZE(8, 8), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
-  {34, UPB_SIZE(4, 4), 2, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {999, UPB_SIZE(12, 16), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {33, UPB_SIZE(8, 8), 1, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
+  {34, UPB_SIZE(4, 4), 2, 0, 14, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {999, UPB_SIZE(12, 16), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_MethodOptions_msginit = {
@@ -401,13 +401,13 @@ static const upb_msglayout_sub google_protobuf_UninterpretedOption_submsgs[1] =
 };
 
 static const upb_msglayout_field google_protobuf_UninterpretedOption__fields[7] = {
-  {2, UPB_SIZE(56, 80), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
-  {3, UPB_SIZE(32, 32), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {4, UPB_SIZE(8, 8), 2, 0, 4, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << 6)},
-  {5, UPB_SIZE(16, 16), 3, 0, 3, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << 6)},
-  {6, UPB_SIZE(24, 24), 4, 0, 1, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << 6)},
-  {7, UPB_SIZE(40, 48), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {8, UPB_SIZE(48, 64), 6, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
+  {2, UPB_SIZE(56, 80), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(32, 32), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(8, 8), 2, 0, 4, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << _UPB_REP_SHIFT)},
+  {5, UPB_SIZE(16, 16), 3, 0, 3, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(24, 24), 4, 0, 1, _UPB_MODE_SCALAR | (_UPB_REP_8BYTE << _UPB_REP_SHIFT)},
+  {7, UPB_SIZE(40, 48), 5, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {8, UPB_SIZE(48, 64), 6, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_UninterpretedOption_msginit = {
@@ -417,8 +417,8 @@ const upb_msglayout google_protobuf_UninterpretedOption_msginit = {
 };
 
 static const upb_msglayout_field google_protobuf_UninterpretedOption_NamePart__fields[2] = {
-  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {2, UPB_SIZE(1, 1), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << 6)},
+  {1, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(1, 1), 2, 0, 8, _UPB_MODE_SCALAR | (_UPB_REP_1BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_UninterpretedOption_NamePart_msginit = {
@@ -432,7 +432,7 @@ static const upb_msglayout_sub google_protobuf_SourceCodeInfo_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_SourceCodeInfo__fields[1] = {
-  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_SourceCodeInfo_msginit = {
@@ -442,11 +442,11 @@ const upb_msglayout google_protobuf_SourceCodeInfo_msginit = {
 };
 
 static const upb_msglayout_field google_protobuf_SourceCodeInfo_Location__fields[5] = {
-  {1, UPB_SIZE(20, 40), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << 6)},
-  {2, UPB_SIZE(24, 48), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << 6)},
-  {3, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {4, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {6, UPB_SIZE(28, 56), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(20, 40), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(24, 48), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(4, 8), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(12, 24), 2, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {6, UPB_SIZE(28, 56), 0, 0, 12, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit = {
@@ -460,7 +460,7 @@ static const upb_msglayout_sub google_protobuf_GeneratedCodeInfo_submsgs[1] = {
 };
 
 static const upb_msglayout_field google_protobuf_GeneratedCodeInfo__fields[1] = {
-  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6)},
+  {1, UPB_SIZE(0, 0), 0, 0, 11, _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit = {
@@ -470,10 +470,10 @@ const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit = {
 };
 
 static const upb_msglayout_field google_protobuf_GeneratedCodeInfo_Annotation__fields[4] = {
-  {1, UPB_SIZE(20, 32), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << 6)},
-  {2, UPB_SIZE(12, 16), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << 6)},
-  {3, UPB_SIZE(4, 4), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
-  {4, UPB_SIZE(8, 8), 3, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << 6)},
+  {1, UPB_SIZE(20, 32), 0, 0, 5, _UPB_MODE_ARRAY | _UPB_MODE_IS_PACKED | (_UPB_REP_PTR << _UPB_REP_SHIFT)},
+  {2, UPB_SIZE(12, 16), 1, 0, 12, _UPB_MODE_SCALAR | (_UPB_REP_STRVIEW << _UPB_REP_SHIFT)},
+  {3, UPB_SIZE(4, 4), 2, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
+  {4, UPB_SIZE(8, 8), 3, 0, 5, _UPB_MODE_SCALAR | (_UPB_REP_4BYTE << _UPB_REP_SHIFT)},
 };
 
 const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit = {
diff --git a/upb/decode.c b/upb/decode.c
index f7992c7165..c981d106e1 100644
--- a/upb/decode.c
+++ b/upb/decode.c
@@ -688,7 +688,7 @@ static const char *decode_msg(upb_decstate *d, const char *ptr, upb_msg *msg,
       }
 
       /* Parse, using op for dispatch. */
-      switch (mode & 3) {
+      switch (mode & _UPB_MODE_MASK) {
         case _UPB_MODE_ARRAY:
           ptr = decode_toarray(d, ptr, field_msg, subs, field, &val, op);
           break;
diff --git a/upb/def.c b/upb/def.c
index d1f3466978..b38c1f6281 100644
--- a/upb/def.c
+++ b/upb/def.c
@@ -1139,9 +1139,9 @@ static void fill_fieldlayout(upb_msglayout_field *field, const upb_fielddef *f)
   }
 
   if (upb_fielddef_ismap(f)) {
-    field->mode = _UPB_MODE_MAP | (_UPB_REP_PTR << 6);
+    field->mode = _UPB_MODE_MAP | (_UPB_REP_PTR << _UPB_REP_SHIFT);
   } else if (upb_fielddef_isseq(f)) {
-    field->mode = _UPB_MODE_ARRAY | (_UPB_REP_PTR << 6);
+    field->mode = _UPB_MODE_ARRAY | (_UPB_REP_PTR << _UPB_REP_SHIFT);
   } else {
     /* Maps descriptor type -> elem_size_lg2.  */
     static const uint8_t sizes[] = {
@@ -1165,7 +1165,8 @@ static void fill_fieldlayout(upb_msglayout_field *field, const upb_fielddef *f)
         _UPB_REP_4BYTE,   /* SINT32 */
         _UPB_REP_8BYTE,   /* SINT64 */
     };
-    field->mode = _UPB_MODE_SCALAR | (sizes[field->descriptortype] << 6);
+    field->mode =
+        _UPB_MODE_SCALAR | (sizes[field->descriptortype] << _UPB_REP_SHIFT);
   }
 
   if (upb_fielddef_packed(f)) {
diff --git a/upb/encode.c b/upb/encode.c
index 25f918afba..33948fbe08 100644
--- a/upb/encode.c
+++ b/upb/encode.c
@@ -427,7 +427,7 @@ static bool encode_shouldencode(upb_encstate *e, const upb_msg *msg,
   if (f->presence == 0) {
     /* Proto3 presence or map/array. */
     const void *mem = UPB_PTR_AT(msg, f->offset, void);
-    switch (f->mode >> 6) {
+    switch (f->mode >> _UPB_REP_SHIFT) {
       case _UPB_REP_1BYTE: {
         char ch;
         memcpy(&ch, mem, 1);
diff --git a/upb/msg.c b/upb/msg.c
index 62580baa89..54426ec721 100644
--- a/upb/msg.c
+++ b/upb/msg.c
@@ -142,7 +142,7 @@ void _upb_msg_clearext(upb_msg *msg, const upb_msglayout_ext *ext_l) {
   if (!in->internal) return;
   const upb_msg_ext *base =
       UPB_PTR_AT(in->internal, in->internal->ext_begin, void);
-  upb_msg_ext *ext = (void*)_upb_msg_getext(msg, ext_l);
+  upb_msg_ext *ext = (upb_msg_ext*)_upb_msg_getext(msg, ext_l);
   if (ext) {
     *ext = *base;
     in->internal->ext_begin += sizeof(upb_msg_ext);
diff --git a/upb/msg_internal.h b/upb/msg_internal.h
index 7b9267e01e..12d9133241 100644
--- a/upb/msg_internal.h
+++ b/upb/msg_internal.h
@@ -69,13 +69,16 @@ typedef struct {
   int16_t presence;       /* If >0, hasbit_index.  If <0, ~oneof_index. */
   uint16_t submsg_index;  /* undefined if descriptortype != MESSAGE or GROUP. */
   uint8_t descriptortype;
-  uint8_t mode;            /* upb_fieldmode | upb_labelflags | (upb_rep << 6) */
+  uint8_t mode; /* upb_fieldmode | upb_labelflags |
+                   (upb_rep << _UPB_REP_SHIFT) */
 } upb_msglayout_field;
 
 typedef enum {
   _UPB_MODE_MAP = 0,
   _UPB_MODE_ARRAY = 1,
   _UPB_MODE_SCALAR = 2,
+
+  _UPB_MODE_MASK = 3,  /* Mask to isolate the mode from upb_rep. */
 } upb_fieldmode;
 
 /* Extra flags on the mode field. */
@@ -97,6 +100,8 @@ enum upb_rep {
 #else
   _UPB_REP_PTR = _UPB_REP_8BYTE,
 #endif
+
+  _UPB_REP_SHIFT = 6,  /* Bit offset of the rep in upb_msglayout_field.mode */
 };
 
 UPB_INLINE upb_fieldmode _upb_getmode(const upb_msglayout_field *field) {
diff --git a/upb/msg_test.cc b/upb/msg_test.cc
new file mode 100644
index 0000000000..528d2e03b2
--- /dev/null
+++ b/upb/msg_test.cc
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2009-2021, Google LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Google LLC nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "gtest/gtest.h"
+#include "src/google/protobuf/test_messages_proto3.upb.h"
+#include "upb/def.hpp"
+#include "upb/json_decode.h"
+#include "upb/json_encode.h"
+#include "upb/msg_test.upb.h"
+#include "upb/msg_test.upbdefs.h"
+#include "upb/upb.hpp"
+
+void VerifyMessage(const upb_test_TestExtensions *ext_msg) {
+  EXPECT_TRUE(upb_test_TestExtensions_has_optional_int32_ext(ext_msg));
+  // EXPECT_FALSE(upb_test_TestExtensions_Nested_has_optional_int32_ext(ext_msg));
+  EXPECT_TRUE(upb_test_has_optional_msg_ext(ext_msg));
+
+  EXPECT_EQ(123, upb_test_TestExtensions_optional_int32_ext(ext_msg));
+  const protobuf_test_messages_proto3_TestAllTypesProto3 *ext_submsg =
+      upb_test_optional_msg_ext(ext_msg);
+  EXPECT_TRUE(ext_submsg != nullptr);
+  EXPECT_EQ(456,
+            protobuf_test_messages_proto3_TestAllTypesProto3_optional_int32(
+                ext_submsg));
+}
+
+TEST(MessageTest, Extensions) {
+  upb::Arena arena;
+  upb_test_TestExtensions *ext_msg = upb_test_TestExtensions_new(arena.ptr());
+
+  EXPECT_FALSE(upb_test_TestExtensions_has_optional_int32_ext(ext_msg));
+  // EXPECT_FALSE(upb_test_TestExtensions_Nested_has_optional_int32_ext(ext_msg));
+  EXPECT_FALSE(upb_test_has_optional_msg_ext(ext_msg));
+
+  upb::SymbolTable symtab;
+  upb::MessageDefPtr m(upb_test_TestExtensions_getmsgdef(symtab.ptr()));
+  EXPECT_TRUE(m.ptr() != nullptr);
+
+  std::string json = R"(
+  {
+      "[upb_test.TestExtensions.optional_int32_ext]": 123,
+      "[upb_test.TestExtensions.Nested.repeated_int32_ext]": [2, 4, 6],
+      "[upb_test.optional_msg_ext]": {"optional_int32": 456}
+  }
+  )";
+  upb::Status status;
+  EXPECT_TRUE(upb_json_decode(json.data(), json.size(), ext_msg, m.ptr(),
+                              symtab.ptr(), 0, arena.ptr(), status.ptr()))
+      << status.error_message();
+
+  VerifyMessage(ext_msg);
+
+  // Test round-trip through binary format.
+  size_t size;
+  char *serialized = upb_test_TestExtensions_serialize(ext_msg, arena.ptr(), &size);
+  ASSERT_TRUE(serialized != nullptr);
+  ASSERT_GE(size, 0);
+
+  upb_test_TestExtensions *ext_msg2 = upb_test_TestExtensions_parse_ex(
+      serialized, size, upb_symtab_extreg(symtab.ptr()), 0, arena.ptr());
+  VerifyMessage(ext_msg2);
+
+  // Test round-trip through JSON format.
+  size_t json_size =
+      upb_json_encode(ext_msg, m.ptr(), symtab.ptr(), 0, NULL, 0, status.ptr());
+  char *json_buf =
+      static_cast<char *>(upb_arena_malloc(arena.ptr(), json_size + 1));
+  upb_json_encode(ext_msg, m.ptr(), symtab.ptr(), 0, json_buf, json_size + 1,
+                  status.ptr());
+  upb_test_TestExtensions *ext_msg3 = upb_test_TestExtensions_new(arena.ptr());
+  fprintf(stderr, "%.*s\n", (int)json_size, json_buf);
+  EXPECT_TRUE(upb_json_decode(json_buf, json_size, ext_msg3, m.ptr(),
+                              symtab.ptr(), 0, arena.ptr(), status.ptr()))
+      << status.error_message();
+  VerifyMessage(ext_msg3);
+}
+
diff --git a/upb/msg_test.proto b/upb/msg_test.proto
new file mode 100644
index 0000000000..5670b304a1
--- /dev/null
+++ b/upb/msg_test.proto
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2009-2021, Google LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Google LLC nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+syntax = "proto2";
+
+import "src/google/protobuf/test_messages_proto3.proto";
+
+package upb_test;
+
+message TestExtensions {
+  extensions 1000 to max;
+  extend TestExtensions {
+    optional int32 optional_int32_ext = 1000;
+  }
+  message Nested {
+    extend TestExtensions {
+      repeated int32 repeated_int32_ext = 1001;
+    }
+  }
+}
+
+extend TestExtensions {
+  optional protobuf_test_messages.proto3.TestAllTypesProto3 optional_msg_ext = 1002;
+}
diff --git a/upb/reflection.c b/upb/reflection.c
index 989ab3af1a..2c3e7e8eea 100644
--- a/upb/reflection.c
+++ b/upb/reflection.c
@@ -158,7 +158,7 @@ upb_msgval upb_msg_get(const upb_msg *msg, const upb_fielddef *f) {
 
 upb_mutmsgval upb_msg_mutable(upb_msg *msg, const upb_fielddef *f,
                               upb_arena *a) {
-  assert(upb_fielddef_issubmsg(f) || upb_fielddef_isseq(f));
+  UPB_ASSERT(upb_fielddef_issubmsg(f) || upb_fielddef_isseq(f));
   if (upb_fielddef_haspresence(f) && !upb_msg_has(msg, f)) {
     // We need to skip the upb_msg_get() call in this case.
     goto make;
diff --git a/upb/reflection.h b/upb/reflection.h
index 5b8f5c2ce7..3c99ff1c4b 100644
--- a/upb/reflection.h
+++ b/upb/reflection.h
@@ -81,7 +81,10 @@ const upb_fielddef *upb_msg_whichoneof(const upb_msg *msg,
                                        const upb_oneofdef *o);
 
 /* Sets the given field to the given value.  For a msg/array/map/string, the
- * value must be in the same arena.  */
+ * caller must ensure that the target data outlives |msg| (by living either in
+ * the same arena or a different arena that outlives it).
+ *
+ * Returns false if allocation fails. */
 bool upb_msg_set(upb_msg *msg, const upb_fielddef *f, upb_msgval val,
                  upb_arena *a);
 
diff --git a/upbc/protoc-gen-upb.cc b/upbc/protoc-gen-upb.cc
index 2de85b5f4c..e49d48174d 100644
--- a/upbc/protoc-gen-upb.cc
+++ b/upbc/protoc-gen-upb.cc
@@ -1008,8 +1008,8 @@ void WriteField(const protobuf::FieldDescriptor* field,
     absl::StrAppend(&mode, " | _UPB_MODE_IS_EXTENSION");
   }
 
-  output("{$0, $1, $2, $3, $4, $5 | ($6 << 6)}", field->number(), offset,
-         presence, submsg_index, TableDescriptorType(field), mode, rep);
+  output("{$0, $1, $2, $3, $4, $5 | ($6 << _UPB_REP_SHIFT)}", field->number(),
+         offset, presence, submsg_index, TableDescriptorType(field), mode, rep);
 }
 
 // Writes a single field into a .upb.c source file.
@@ -1170,19 +1170,25 @@ int WriteExtensions(const protobuf::FileDescriptor* file, Output& output) {
 
   if (exts.empty()) return 0;
 
+  // Order by full name for consistent ordering.
+  std::map<std::string, const protobuf::Descriptor*> forward_messages;
+  auto add_forward_decl = [&](const protobuf::Descriptor* d) {
+    forward_messages[d->full_name()] = d;
+  };
+
   for (auto ext : exts) {
-    forward_decls.insert(ext->containing_type());
+    add_forward_decl(ext->containing_type());
     if (ext->message_type()) {
-      forward_decls.insert(ext->message_type());
+      add_forward_decl(ext->message_type());
     }
   }
 
-  for (auto ext : exts) {
-    WriteExtension(ext, output);
+  for (auto decl : forward_messages) {
+    output("extern const upb_msglayout $0;\n", MessageInit(decl.second));
   }
 
-  for (auto decl : forward_decls) {
-    output("extern const upb_msglayout $0;\n", MessageInit(decl));
+  for (auto ext : exts) {
+    WriteExtension(ext, output);
   }
 
   output(