Merge branch 'data-refactoring'. Ported benchmarks.

Conflicts:

	src/upb_data.c
	src/upb_data.h

10 files changed, 364 insertions, 324 deletions

diff --git a/benchmarks/parsetostruct.upb_table.c b/benchmarks/parsetostruct.upb_table.c
index 045aedb..e387de6 100644
--- a/benchmarks/parsetostruct.upb_table.c
+++ b/benchmarks/parsetostruct.upb_table.c
@@ -1,14 +1,13 @@
 
 #include "main.c"
 
+#include "upb_data.h"
 #include "upb_def.h"
-#include "upb_mm.h"
-#include "upb_msg.h"
 
 static struct upb_symtab *s;
-static struct upb_string *str;
+static upb_strptr str;
 static struct upb_msgdef *def;
-static struct upb_msg *msgs[NUM_MESSAGES];
+static upb_msg *msgs[NUM_MESSAGES];
 static struct upb_msgparser *mp;
 
 static bool initialize()
@@ -16,8 +15,8 @@ static bool initialize()
   // Initialize upb state, parse descriptor.
   struct upb_status status = UPB_STATUS_INIT;
   s = upb_symtab_new();
-  struct upb_string *fds = upb_strreadfile(MESSAGE_DESCRIPTOR_FILE);
-  if(!fds) {
+  upb_strptr fds = upb_strreadfile(MESSAGE_DESCRIPTOR_FILE);
+  if(upb_string_isnull(fds)) {
     fprintf(stderr, "Couldn't read " MESSAGE_DESCRIPTOR_FILE ": %s.\n",
             status.msg);
     return false;
@@ -30,7 +29,7 @@ static bool initialize()
   }
   upb_string_unref(fds);
 
-  struct upb_string *proto_name = upb_strdupc(MESSAGE_NAME);
+  upb_strptr proto_name = upb_strdupc(MESSAGE_NAME);
   def = upb_downcast_msgdef(upb_symtab_lookup(s, proto_name));
   if(!def) {
     fprintf(stderr, "Error finding symbol '" UPB_STRFMT "'.\n",
@@ -44,7 +43,7 @@ static bool initialize()
 
   // Read the message data itself.
   str = upb_strreadfile(MESSAGE_FILE);
-  if(!str) {
+  if(upb_string_isnull(str)) {
     fprintf(stderr, "Error reading " MESSAGE_FILE "\n");
     return false;
   }
@@ -55,7 +54,7 @@ static bool initialize()
 static void cleanup()
 {
   for(int i = 0; i < NUM_MESSAGES; i++)
-    upb_msg_unref(msgs[i]);
+    upb_msg_unref(msgs[i], def);
   upb_string_unref(str);
   upb_symtab_unref(s);
   upb_msgparser_free(mp);
@@ -64,13 +63,13 @@ static void cleanup()
 static size_t run(int i)
 {
   struct upb_status status = UPB_STATUS_INIT;
-  struct upb_msg *msg = msgs[i%NUM_MESSAGES];
-  upb_msgparser_reset(mp, msg, false);
-  upb_msg_clear(msg);
-  upb_msgparser_parse(mp, str->ptr, str->byte_len, &status);
+  upb_msg *msg = msgs[i%NUM_MESSAGES];
+  upb_msgparser_reset(mp, msg);
+  upb_msg_clear(msg, def);
+  upb_msgparser_parse(mp, str, &status);
   if(!upb_ok(&status)) {
     fprintf(stderr, "Parse error: %s\n", status.msg);
     return 0;
   }
-  return str->byte_len;
+  return upb_strlen(str);
 }
diff --git a/descriptor/descriptor.c b/descriptor/descriptor.c
index 61195b3..c722b25 100644
--- a/descriptor/descriptor.c
+++ b/descriptor/descriptor.c
@@ -181,18 +181,18 @@ static google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_array_el
     &google_protobuf_DescriptorProto_values[16],
     &google_protobuf_DescriptorProto_values[17],
 };
-static UPB_MSG_ARRAY(google_protobuf_DescriptorProto) google_protobuf_DescriptorProto_arrays[3] = {
-  {.elements = &google_protobuf_DescriptorProto_array_elems[0], .len=16},
-  {.elements = &google_protobuf_DescriptorProto_array_elems[16], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_array_elems[17], .len=1},
+static upb_static_array google_protobuf_DescriptorProto_arrays[3] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_array_elems[0], 16),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_array_elems[16], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_array_elems[17], 1),
 };
 static google_protobuf_FileDescriptorProto google_protobuf_FileDescriptorProto_values[1];
 
 static google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_array_elems[] = {
     &google_protobuf_FileDescriptorProto_values[0],
 };
-static UPB_MSG_ARRAY(google_protobuf_FileDescriptorProto) google_protobuf_FileDescriptorProto_arrays[1] = {
-  {.elements = &google_protobuf_FileDescriptorProto_array_elems[0], .len=1},
+static upb_static_array google_protobuf_FileDescriptorProto_arrays[1] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FileDescriptorProto_array_elems[0], 1),
 };
 static google_protobuf_FileDescriptorSet google_protobuf_FileDescriptorSet_values[1];
 
@@ -207,14 +207,14 @@ static google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_Descripto
     &google_protobuf_DescriptorProto_ExtensionRange_values[5],
     &google_protobuf_DescriptorProto_ExtensionRange_values[6],
 };
-static UPB_MSG_ARRAY(google_protobuf_DescriptorProto_ExtensionRange) google_protobuf_DescriptorProto_ExtensionRange_arrays[7] = {
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[0], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[1], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[2], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[3], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[4], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[5], .len=1},
-  {.elements = &google_protobuf_DescriptorProto_ExtensionRange_array_elems[6], .len=1},
+static upb_static_array google_protobuf_DescriptorProto_ExtensionRange_arrays[7] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[0], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[1], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[2], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[3], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[4], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[5], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_DescriptorProto_ExtensionRange_array_elems[6], 1),
 };
 static google_protobuf_FileOptions google_protobuf_FileOptions_values[1];
 
@@ -226,10 +226,10 @@ static google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_
     &google_protobuf_EnumDescriptorProto_values[2],
     &google_protobuf_EnumDescriptorProto_values[3],
 };
-static UPB_MSG_ARRAY(google_protobuf_EnumDescriptorProto) google_protobuf_EnumDescriptorProto_arrays[3] = {
-  {.elements = &google_protobuf_EnumDescriptorProto_array_elems[0], .len=2},
-  {.elements = &google_protobuf_EnumDescriptorProto_array_elems[2], .len=1},
-  {.elements = &google_protobuf_EnumDescriptorProto_array_elems[3], .len=1},
+static upb_static_array google_protobuf_EnumDescriptorProto_arrays[3] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumDescriptorProto_array_elems[0], 2),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumDescriptorProto_array_elems[2], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumDescriptorProto_array_elems[3], 1),
 };
 static google_protobuf_FieldDescriptorProto google_protobuf_FieldDescriptorProto_values[63];
 
@@ -298,25 +298,25 @@ static google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProt
     &google_protobuf_FieldDescriptorProto_values[61],
     &google_protobuf_FieldDescriptorProto_values[62],
 };
-static UPB_MSG_ARRAY(google_protobuf_FieldDescriptorProto) google_protobuf_FieldDescriptorProto_arrays[18] = {
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[0], .len=1},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[1], .len=8},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[9], .len=7},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[16], .len=2},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[18], .len=8},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[26], .len=3},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[29], .len=3},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[32], .len=3},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[35], .len=4},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[39], .len=5},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[44], .len=2},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[46], .len=5},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[51], .len=1},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[52], .len=1},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[53], .len=1},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[54], .len=1},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[55], .len=6},
-  {.elements = &google_protobuf_FieldDescriptorProto_array_elems[61], .len=2},
+static upb_static_array google_protobuf_FieldDescriptorProto_arrays[18] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[0], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[1], 8),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[9], 7),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[16], 2),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[18], 8),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[26], 3),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[29], 3),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[32], 3),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[35], 4),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[39], 5),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[44], 2),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[46], 5),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[51], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[52], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[53], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[54], 1),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[55], 6),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_FieldDescriptorProto_array_elems[61], 2),
 };
 static google_protobuf_EnumValueDescriptorProto google_protobuf_EnumValueDescriptorProto_values[25];
 
@@ -347,11 +347,11 @@ static google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescri
     &google_protobuf_EnumValueDescriptorProto_values[23],
     &google_protobuf_EnumValueDescriptorProto_values[24],
 };
-static UPB_MSG_ARRAY(google_protobuf_EnumValueDescriptorProto) google_protobuf_EnumValueDescriptorProto_arrays[4] = {
-  {.elements = &google_protobuf_EnumValueDescriptorProto_array_elems[0], .len=18},
-  {.elements = &google_protobuf_EnumValueDescriptorProto_array_elems[18], .len=3},
-  {.elements = &google_protobuf_EnumValueDescriptorProto_array_elems[21], .len=2},
-  {.elements = &google_protobuf_EnumValueDescriptorProto_array_elems[23], .len=2},
+static upb_static_array google_protobuf_EnumValueDescriptorProto_arrays[4] = {
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumValueDescriptorProto_array_elems[0], 18),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumValueDescriptorProto_array_elems[18], 3),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumValueDescriptorProto_array_elems[21], 2),
+  UPB_STATIC_ARRAY_INIT(&google_protobuf_EnumValueDescriptorProto_array_elems[23], 2),
 };
 static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18] = {
 
@@ -366,11 +366,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[34]),   /* "FileDescriptorSet" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[0],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[0]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -384,11 +384,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[33]),   /* "FileDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[1],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[1]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -402,11 +402,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[24]),   /* "DescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[2],
-    .nested_type = &google_protobuf_DescriptorProto_arrays[1],
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[2]),
+    .nested_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_arrays[1]),
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -420,11 +420,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[31]),   /* "FieldDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[4],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = &google_protobuf_EnumDescriptorProto_arrays[0],
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[4]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumDescriptorProto_arrays[0]),
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -438,11 +438,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[26]),   /* "EnumDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[5],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[5]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -456,11 +456,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[28]),   /* "EnumValueDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[6],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[6]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -474,11 +474,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[47]),   /* "ServiceDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[7],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[7]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -492,11 +492,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[41]),   /* "MethodDescriptorProto" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[8],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[8]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -510,11 +510,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[35]),   /* "FileOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[9],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = &google_protobuf_EnumDescriptorProto_arrays[1],
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[0],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[9]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumDescriptorProto_arrays[1]),
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[0]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -528,11 +528,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[40]),   /* "MessageOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[10],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[1],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[10]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[1]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -546,11 +546,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[32]),   /* "FieldOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[11],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = &google_protobuf_EnumDescriptorProto_arrays[2],
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[2],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[11]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumDescriptorProto_arrays[2]),
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[2]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -564,11 +564,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[27]),   /* "EnumOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[12],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[3],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[12]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[3]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -582,11 +582,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[29]),   /* "EnumValueOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[13],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[4],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[13]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[4]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -600,11 +600,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[48]),   /* "ServiceOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[14],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[5],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[14]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[5]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -618,11 +618,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[42]),   /* "MethodOptions" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[15],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = &google_protobuf_DescriptorProto_ExtensionRange_arrays[6],
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[15]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_ExtensionRange_arrays[6]),
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -636,11 +636,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[68]),   /* "UninterpretedOption" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[16],
-    .nested_type = &google_protobuf_DescriptorProto_arrays[2],
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[16]),
+    .nested_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_arrays[2]),
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -654,11 +654,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[30]),   /* "ExtensionRange" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[3],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[3]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -672,11 +672,11 @@ static google_protobuf_DescriptorProto google_protobuf_DescriptorProto_values[18
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[43]),   /* "NamePart" */
-    .field = &google_protobuf_FieldDescriptorProto_arrays[17],
-    .nested_type = 0,   /* Not set. */
-    .enum_type = 0,   /* Not set. */
-    .extension_range = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .field = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FieldDescriptorProto_arrays[17]),
+    .nested_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension_range = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = 0,   /* Not set. */
   },
 };
@@ -695,11 +695,11 @@ static google_protobuf_FileDescriptorProto google_protobuf_FileDescriptorProto_v
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[74]),   /* "descriptor/descriptor.proto" */
     .package = UPB_STATIC_STRING_PTR_INIT(strings[85]),   /* "google.protobuf" */
-    .dependency = 0,   /* Not set. */
-    .message_type = &google_protobuf_DescriptorProto_arrays[0],
-    .enum_type = 0,   /* Not set. */
-    .service = 0,   /* Not set. */
-    .extension = 0,   /* Not set. */
+    .dependency = UPB_ARRAY_NULL_INITIALIZER,   /* Not set. */
+    .message_type = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_DescriptorProto_arrays[0]),
+    .enum_type = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .service = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
+    .extension = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
     .options = &google_protobuf_FileOptions_values[0],
   },
 };
@@ -709,7 +709,7 @@ static google_protobuf_FileDescriptorSet google_protobuf_FileDescriptorSet_value
    .set_flags = {.has = {
     .file = true,
   }},
-    .file = &google_protobuf_FileDescriptorProto_arrays[0],
+    .file = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_FileDescriptorProto_arrays[0]),
   },
 };
 static google_protobuf_DescriptorProto_ExtensionRange google_protobuf_DescriptorProto_ExtensionRange_values[7] = {
@@ -785,7 +785,7 @@ static google_protobuf_FileOptions google_protobuf_FileOptions_values[1] = {
     .java_outer_classname = UPB_STATIC_STRING_PTR_INIT(strings[25]),   /* "DescriptorProtos" */
     .optimize_for = 1,
     .java_multiple_files = 0,   /* Not set. */
-    .uninterpreted_option = 0,   /* Not set. */
+    .uninterpreted_option = {UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */
   },
 };
 static google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto_values[4] = {
@@ -797,7 +797,7 @@ static google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto_v
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[67]),   /* "Type" */
-    .value = &google_protobuf_EnumValueDescriptorProto_arrays[0],
+    .value = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumValueDescriptorProto_arrays[0]),
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -807,7 +807,7 @@ static google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto_v
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[39]),   /* "Label" */
-    .value = &google_protobuf_EnumValueDescriptorProto_arrays[1],
+    .value = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumValueDescriptorProto_arrays[1]),
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -817,7 +817,7 @@ static google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto_v
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[44]),   /* "OptimizeMode" */
-    .value = &google_protobuf_EnumValueDescriptorProto_arrays[2],
+    .value = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumValueDescriptorProto_arrays[2]),
     .options = 0,   /* Not set. */
   },
   {.base = {UPB_DATA_FROZEN},
@@ -827,7 +827,7 @@ static google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto_v
     .options = false,
   }},
     .name = UPB_STATIC_STRING_PTR_INIT(strings[23]),   /* "CType" */
-    .value = &google_protobuf_EnumValueDescriptorProto_arrays[3],
+    .value = UPB_STATIC_ARRAY_PTR_TYPED_INIT(google_protobuf_EnumValueDescriptorProto_arrays[3]),
     .options = 0,   /* Not set. */
   },
 };
diff --git a/descriptor/descriptor.h b/descriptor/descriptor.h
index 8db5bd3..8c59624 100644
--- a/descriptor/descriptor.h
+++ b/descriptor/descriptor.h
@@ -18,74 +18,92 @@ extern struct google_protobuf_FileDescriptorSet *upb_file_descriptor_set;
 struct google_protobuf_UninterpretedOption_NamePart;
 typedef struct google_protobuf_UninterpretedOption_NamePart
     google_protobuf_UninterpretedOption_NamePart;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_UninterpretedOption_NamePart)
 
 struct google_protobuf_DescriptorProto;
 typedef struct google_protobuf_DescriptorProto
     google_protobuf_DescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_DescriptorProto)
 
 struct google_protobuf_EnumDescriptorProto;
 typedef struct google_protobuf_EnumDescriptorProto
     google_protobuf_EnumDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumDescriptorProto)
 
 struct google_protobuf_UninterpretedOption;
 typedef struct google_protobuf_UninterpretedOption
     google_protobuf_UninterpretedOption;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_UninterpretedOption)
 
 struct google_protobuf_FileDescriptorProto;
 typedef struct google_protobuf_FileDescriptorProto
     google_protobuf_FileDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_FileDescriptorProto)
 
 struct google_protobuf_MethodDescriptorProto;
 typedef struct google_protobuf_MethodDescriptorProto
     google_protobuf_MethodDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_MethodDescriptorProto)
 
 struct google_protobuf_EnumValueOptions;
 typedef struct google_protobuf_EnumValueOptions
     google_protobuf_EnumValueOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumValueOptions)
 
 struct google_protobuf_EnumValueDescriptorProto;
 typedef struct google_protobuf_EnumValueDescriptorProto
     google_protobuf_EnumValueDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumValueDescriptorProto)
 
 struct google_protobuf_ServiceDescriptorProto;
 typedef struct google_protobuf_ServiceDescriptorProto
     google_protobuf_ServiceDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_ServiceDescriptorProto)
 
 struct google_protobuf_FileDescriptorSet;
 typedef struct google_protobuf_FileDescriptorSet
     google_protobuf_FileDescriptorSet;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_FileDescriptorSet)
 
 struct google_protobuf_DescriptorProto_ExtensionRange;
 typedef struct google_protobuf_DescriptorProto_ExtensionRange
     google_protobuf_DescriptorProto_ExtensionRange;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_DescriptorProto_ExtensionRange)
 
 struct google_protobuf_FieldOptions;
 typedef struct google_protobuf_FieldOptions
     google_protobuf_FieldOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_FieldOptions)
 
 struct google_protobuf_FileOptions;
 typedef struct google_protobuf_FileOptions
     google_protobuf_FileOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_FileOptions)
 
 struct google_protobuf_MessageOptions;
 typedef struct google_protobuf_MessageOptions
     google_protobuf_MessageOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_MessageOptions)
 
 struct google_protobuf_EnumOptions;
 typedef struct google_protobuf_EnumOptions
     google_protobuf_EnumOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumOptions)
 
 struct google_protobuf_FieldDescriptorProto;
 typedef struct google_protobuf_FieldDescriptorProto
     google_protobuf_FieldDescriptorProto;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_FieldDescriptorProto)
 
 struct google_protobuf_ServiceOptions;
 typedef struct google_protobuf_ServiceOptions
     google_protobuf_ServiceOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_ServiceOptions)
 
 struct google_protobuf_MethodOptions;
 typedef struct google_protobuf_MethodOptions
     google_protobuf_MethodOptions;
+UPB_DEFINE_MSG_ARRAY(google_protobuf_MethodOptions)
 
 /* The message definitions themselves. */
 
@@ -101,7 +119,6 @@ struct google_protobuf_UninterpretedOption_NamePart {
   upb_strptr name_part;
   bool is_extension;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_UninterpretedOption_NamePart)
 
 struct google_protobuf_DescriptorProto {
   upb_data base;
@@ -118,14 +135,13 @@ struct google_protobuf_DescriptorProto {
     } has;
   } set_flags;
   upb_strptr name;
-  UPB_MSG_ARRAY(google_protobuf_FieldDescriptorProto)* field;
-  UPB_MSG_ARRAY(google_protobuf_DescriptorProto)* nested_type;
-  UPB_MSG_ARRAY(google_protobuf_EnumDescriptorProto)* enum_type;
-  UPB_MSG_ARRAY(google_protobuf_DescriptorProto_ExtensionRange)* extension_range;
-  UPB_MSG_ARRAY(google_protobuf_FieldDescriptorProto)* extension;
+  UPB_MSG_ARRAYPTR(google_protobuf_FieldDescriptorProto) field;
+  UPB_MSG_ARRAYPTR(google_protobuf_DescriptorProto) nested_type;
+  UPB_MSG_ARRAYPTR(google_protobuf_EnumDescriptorProto) enum_type;
+  UPB_MSG_ARRAYPTR(google_protobuf_DescriptorProto_ExtensionRange) extension_range;
+  UPB_MSG_ARRAYPTR(google_protobuf_FieldDescriptorProto) extension;
   google_protobuf_MessageOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_DescriptorProto)
 
 struct google_protobuf_EnumDescriptorProto {
   upb_data base;
@@ -138,10 +154,9 @@ struct google_protobuf_EnumDescriptorProto {
     } has;
   } set_flags;
   upb_strptr name;
-  UPB_MSG_ARRAY(google_protobuf_EnumValueDescriptorProto)* value;
+  UPB_MSG_ARRAYPTR(google_protobuf_EnumValueDescriptorProto) value;
   google_protobuf_EnumOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumDescriptorProto)
 
 struct google_protobuf_UninterpretedOption {
   upb_data base;
@@ -156,14 +171,13 @@ struct google_protobuf_UninterpretedOption {
       bool string_value:1;  /* = 7, optional. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption_NamePart)* name;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption_NamePart) name;
   upb_strptr identifier_value;
   uint64_t positive_int_value;
   int64_t negative_int_value;
   double double_value;
   upb_strptr string_value;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_UninterpretedOption)
 
 struct google_protobuf_FileDescriptorProto {
   upb_data base;
@@ -182,14 +196,13 @@ struct google_protobuf_FileDescriptorProto {
   } set_flags;
   upb_strptr name;
   upb_strptr package;
-  upb_array* dependency;
-  UPB_MSG_ARRAY(google_protobuf_DescriptorProto)* message_type;
-  UPB_MSG_ARRAY(google_protobuf_EnumDescriptorProto)* enum_type;
-  UPB_MSG_ARRAY(google_protobuf_ServiceDescriptorProto)* service;
-  UPB_MSG_ARRAY(google_protobuf_FieldDescriptorProto)* extension;
+  upb_arrayptr dependency;
+  UPB_MSG_ARRAYPTR(google_protobuf_DescriptorProto) message_type;
+  UPB_MSG_ARRAYPTR(google_protobuf_EnumDescriptorProto) enum_type;
+  UPB_MSG_ARRAYPTR(google_protobuf_ServiceDescriptorProto) service;
+  UPB_MSG_ARRAYPTR(google_protobuf_FieldDescriptorProto) extension;
   google_protobuf_FileOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_FileDescriptorProto)
 
 struct google_protobuf_MethodDescriptorProto {
   upb_data base;
@@ -207,7 +220,6 @@ struct google_protobuf_MethodDescriptorProto {
   upb_strptr output_type;
   google_protobuf_MethodOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_MethodDescriptorProto)
 
 struct google_protobuf_EnumValueOptions {
   upb_data base;
@@ -217,9 +229,8 @@ struct google_protobuf_EnumValueOptions {
       bool uninterpreted_option:1;  /* = 999, repeated. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumValueOptions)
 
 struct google_protobuf_EnumValueDescriptorProto {
   upb_data base;
@@ -235,7 +246,6 @@ struct google_protobuf_EnumValueDescriptorProto {
   int32_t number;
   google_protobuf_EnumValueOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumValueDescriptorProto)
 
 struct google_protobuf_ServiceDescriptorProto {
   upb_data base;
@@ -248,10 +258,9 @@ struct google_protobuf_ServiceDescriptorProto {
     } has;
   } set_flags;
   upb_strptr name;
-  UPB_MSG_ARRAY(google_protobuf_MethodDescriptorProto)* method;
+  UPB_MSG_ARRAYPTR(google_protobuf_MethodDescriptorProto) method;
   google_protobuf_ServiceOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_ServiceDescriptorProto)
 
 struct google_protobuf_FileDescriptorSet {
   upb_data base;
@@ -261,9 +270,8 @@ struct google_protobuf_FileDescriptorSet {
       bool file:1;  /* = 1, repeated. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_FileDescriptorProto)* file;
+  UPB_MSG_ARRAYPTR(google_protobuf_FileDescriptorProto) file;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_FileDescriptorSet)
 
 struct google_protobuf_DescriptorProto_ExtensionRange {
   upb_data base;
@@ -277,7 +285,6 @@ struct google_protobuf_DescriptorProto_ExtensionRange {
   int32_t start;
   int32_t end;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_DescriptorProto_ExtensionRange)
 
 struct google_protobuf_FieldOptions {
   upb_data base;
@@ -295,9 +302,8 @@ struct google_protobuf_FieldOptions {
   bool packed;
   bool deprecated;
   upb_strptr experimental_map_key;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_FieldOptions)
 
 struct google_protobuf_FileOptions {
   upb_data base;
@@ -315,9 +321,8 @@ struct google_protobuf_FileOptions {
   upb_strptr java_outer_classname;
   int32_t optimize_for;
   bool java_multiple_files;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_FileOptions)
 
 struct google_protobuf_MessageOptions {
   upb_data base;
@@ -329,9 +334,8 @@ struct google_protobuf_MessageOptions {
     } has;
   } set_flags;
   bool message_set_wire_format;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_MessageOptions)
 
 struct google_protobuf_EnumOptions {
   upb_data base;
@@ -341,9 +345,8 @@ struct google_protobuf_EnumOptions {
       bool uninterpreted_option:1;  /* = 999, repeated. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_EnumOptions)
 
 struct google_protobuf_FieldDescriptorProto {
   upb_data base;
@@ -369,7 +372,6 @@ struct google_protobuf_FieldDescriptorProto {
   upb_strptr default_value;
   google_protobuf_FieldOptions* options;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_FieldDescriptorProto)
 
 struct google_protobuf_ServiceOptions {
   upb_data base;
@@ -379,9 +381,8 @@ struct google_protobuf_ServiceOptions {
       bool uninterpreted_option:1;  /* = 999, repeated. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_ServiceOptions)
 
 struct google_protobuf_MethodOptions {
   upb_data base;
@@ -391,9 +392,8 @@ struct google_protobuf_MethodOptions {
       bool uninterpreted_option:1;  /* = 999, repeated. */
     } has;
   } set_flags;
-  UPB_MSG_ARRAY(google_protobuf_UninterpretedOption)* uninterpreted_option;
+  UPB_MSG_ARRAYPTR(google_protobuf_UninterpretedOption) uninterpreted_option;
 };
-UPB_DEFINE_MSG_ARRAY(google_protobuf_MethodOptions)
 
 #ifdef __cplusplus
 }  /* extern "C" */
diff --git a/src/upb.h b/src/upb.h
index 2809418..2c0a23d 100644
--- a/src/upb.h
+++ b/src/upb.h
@@ -125,11 +125,10 @@ struct upb_tag {
 
 // INTERNAL-ONLY: never refer to these types with a tag ("union", "struct").
 // Always use the typedefs.
-union _upb_array;
 struct _upb_msg;
 
-typedef union _upb_array upb_array;
 typedef struct _upb_msg upb_msg;
+
 typedef upb_atomic_refcount_t upb_data;
 
 typedef uint32_t upb_strlen_t;
@@ -143,6 +142,15 @@ typedef union {
   upb_data *base;
 } upb_strptr;
 
+typedef uint32_t upb_arraylen_t;
+
+typedef union {
+  // Must be first, for the UPB_STATIC_ARRAY_PTR_INIT() macro.
+  struct upb_norefcount_array *norefcount;
+  struct upb_refcounted_array *refcounted;
+  upb_data *base;
+} upb_arrayptr;
+
 // A single .proto value.  The owner must have an out-of-band way of knowing
 // the type, so that it knows which union member to use.
 union upb_value {
@@ -154,7 +162,7 @@ union upb_value {
   uint64_t uint64;
   bool _bool;
   upb_strptr str;
-  upb_array *arr;
+  upb_arrayptr arr;
   upb_msg *msg;
   upb_data *data;
 };
@@ -171,7 +179,7 @@ union upb_value_ptr {
   uint64_t *uint64;
   bool *_bool;
   upb_strptr *str;
-  upb_array **arr;
+  upb_arrayptr *arr;
   upb_msg **msg;
   upb_data **data;
   void *_void;
diff --git a/src/upb_data.c b/src/upb_data.c
index 1bb76aa..a0a588a 100644
--- a/src/upb_data.c
+++ b/src/upb_data.c
@@ -57,11 +57,11 @@ static void check_not_frozen(upb_data *d) {
 
 /* upb_string *******************************************************************/
 
-static char *_upb_string_setptr(upb_strptr s, char *ptr) {
+void _upb_string_setptr(upb_strptr s, char *ptr) {
   if(upb_data_hasflag(s.base, UPB_DATA_REFCOUNTED))
-    return s.refcounted->ptr = ptr;
+    s.refcounted->ptr = ptr;
   else
-    return s.norefcount->ptr = ptr;
+    s.norefcount->ptr = ptr;
 }
 
 static void _upb_string_set_bytelen(upb_strptr s, upb_strlen_t newlen) {
@@ -182,64 +182,79 @@ int upb_strcmp(upb_strptr s1, upb_strptr s2) {
 
 /* upb_array ******************************************************************/
 
-upb_array *upb_array_new() {
-  upb_array *a = malloc(sizeof(upb_refcounted_array));
-  data_init(&a->common.base, UPB_DATA_HEAPALLOCATED | UPB_DATA_REFCOUNTED);
-  a->refcounted.size = 0;
-  a->common.len = 0;
-  a->common.elements._void = NULL;
+static void _upb_array_setptr(upb_arrayptr a, void *ptr) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED))
+    a.refcounted->elements._void = ptr;
+  else
+    a.norefcount->elements._void = ptr;
+}
+
+static void _upb_array_setlen(upb_arrayptr a, upb_strlen_t newlen) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED)) {
+    a.refcounted->len = newlen;
+  } else {
+    a.norefcount->len = newlen;
+  }
+}
+
+upb_arrayptr upb_array_new() {
+  upb_arrayptr a;
+  a.refcounted = malloc(sizeof(struct upb_refcounted_array));
+  data_init(a.base, UPB_DATA_HEAPALLOCATED | UPB_DATA_REFCOUNTED);
+  a.refcounted->size = 0;
+  a.refcounted->len = 0;
+  a.refcounted->elements._void = NULL;
   return a;
 }
 
 // ONLY handles refcounted arrays for the moment.
-void _upb_array_free(upb_array *a, struct upb_fielddef *f)
+void _upb_array_free(upb_arrayptr a, struct upb_fielddef *f)
 {
   if(upb_elem_ismm(f)) {
-    for(upb_arraylen_t i = 0; i < a->refcounted.size; i++) {
+    for(upb_arraylen_t i = 0; i < a.refcounted->size; i++) {
       union upb_value_ptr p = _upb_array_getptr(a, f, i);
       if(!*p.data) continue;
       data_elem_unref(p, f);
     }
   }
-  if(a->refcounted.size != 0) free(a->common.elements._void);
-  free(a);
+  if(a.refcounted->size != 0) free(a.refcounted->elements._void);
+  free(a.refcounted);
 }
 
-static upb_arraylen_t array_get_size(upb_array *a) {
-  if(upb_data_hasflag(&a->common.base, UPB_DATA_REFCOUNTED)) {
-    return a->refcounted.size;
+static upb_arraylen_t array_get_size(upb_arrayptr a) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED)) {
+    return a.refcounted->size;
   } else {
-    return (a->norefcount.size_and_flags & 0xFFFFFFF8) >> 3;
+    return (a.norefcount->base.v & 0xFFFFFFF8) >> 3;
   }
 }
 
-static void array_set_size(upb_array *a, upb_arraylen_t newsize) {
-  if(upb_data_hasflag(&a->common.base, UPB_DATA_REFCOUNTED)) {
-    a->refcounted.size = newsize;
+static void array_set_size(upb_arrayptr a, upb_arraylen_t newsize) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED)) {
+    a.refcounted->size = newsize;
   } else {
-    a->norefcount.size_and_flags &= 0x7;
-    a->norefcount.size_and_flags |= (newsize << 3);
+    a.norefcount->base.v &= 0x7;
+    a.norefcount->base.v |= (newsize << 3);
   }
 }
 
-void upb_array_resize(upb_array *a, struct upb_fielddef *f, upb_strlen_t len) {
-  check_not_frozen(&a->common.base);
+void upb_array_resize(upb_arrayptr a, struct upb_fielddef *f, upb_strlen_t len) {
+  check_not_frozen(a.base);
   size_t type_size = upb_type_info[f->type].size;
   upb_arraylen_t old_size = array_get_size(a);
   if(old_size < len) {
     // Need to resize.
     size_t new_size = round_up_to_pow2(len);
-    a->common.elements._void = realloc(a->common.elements._void, new_size * type_size);
+    _upb_array_setptr(a, realloc(_upb_array_getptr_raw(a, 0, 0)._void, new_size * type_size));
     array_set_size(a, new_size);
-    memset(UPB_INDEX(a->common.elements._void, old_size, type_size),
+    memset(_upb_array_getptr_raw(a, old_size, type_size)._void,
            0,
            (new_size - old_size) * type_size);
   }
-  a->common.len = len;
+  _upb_array_setlen(a, len);
 }
 
 
-
 /* upb_msg ********************************************************************/
 
 static void upb_msg_sethas(upb_msg *msg, struct upb_fielddef *f) {
@@ -289,19 +304,15 @@ static union upb_value_ptr get_value_ptr(upb_msg *msg, struct upb_fielddef *f)
   union upb_value_ptr p = _upb_msg_getptr(msg, f);
   if(upb_isarray(f)) {
     if(!upb_msg_has(msg, f)) {
-      if(!*p.arr || !upb_data_only(*p.data)) {
-        printf("Initializing array field " UPB_STRFMT "\n", UPB_STRARG(f->name));
-        if(*p.arr)
+      if(upb_array_isnull(*p.arr) || !upb_data_only(*p.data)) {
+        if(!upb_array_isnull(*p.arr))
           upb_array_unref(*p.arr, f);
         *p.arr = upb_array_new();
-      } else {
-        printf("REUSING array field " UPB_STRFMT "\n", UPB_STRARG(f->name));
       }
       upb_array_truncate(*p.arr);
       upb_msg_sethas(msg, f);
     } else {
-      printf("APPENDING TO EXISTING array field " UPB_STRFMT "\n", UPB_STRARG(f->name));
-      assert(*p.arr);
+      assert(!upb_array_isnull(*p.arr));
     }
     upb_arraylen_t oldlen = upb_array_len(*p.arr);
     upb_array_resize(*p.arr, f, oldlen + 1);
diff --git a/src/upb_data.h b/src/upb_data.h
index 15e87c5..98243ce 100644
--- a/src/upb_data.h
+++ b/src/upb_data.h
@@ -213,9 +213,7 @@ upb_strptr upb_string_getref(upb_strptr s, int ref_flags);
 
 #define UPB_STRING_NULL_INITIALIZER {NULL}
 static const upb_strptr UPB_STRING_NULL = UPB_STRING_NULL_INITIALIZER;
-INLINE bool upb_string_isnull(upb_strptr s) {
-  return s.base == NULL;
-}
+INLINE bool upb_string_isnull(upb_strptr s) { return s.base == NULL; }
 
 // The caller releases a ref on src, which it must previously have owned a ref
 // on.
@@ -350,70 +348,77 @@ typedef struct upb_norefcount_string upb_static_string;
 
 /* upb_array ******************************************************************/
 
-typedef uint32_t upb_arraylen_t;
-
 // The comments attached to upb_string above also apply here.
-typedef struct {
-  upb_data base;
-  upb_arraylen_t len;
-  union upb_value_ptr elements;
-} upb_array_common;
-
-typedef struct {
-  uint32_t size_and_flags;
+struct upb_norefcount_array {
+  upb_data base;  // We co-opt the refcount for the size.
   upb_arraylen_t len;
   union upb_value_ptr elements;
-} upb_norefcount_array;
+};
 
-typedef struct {
+struct upb_refcounted_array {
   upb_data base;
   upb_arraylen_t len;
   union upb_value_ptr elements;
   upb_arraylen_t size;
-} upb_refcounted_array;
-
-union _upb_array {
-  upb_norefcount_array norefcount;
-  upb_array_common common;
-  upb_refcounted_array refcounted;
 };
 
-// This type can be used either to perform read-only access on an array,
-// or to statically define a non-reference-counted static array.
-#define UPB_DEFINE_MSG_ARRAY(type) \
-typedef struct type ## _array { \
-  upb_data base; \
-  upb_arraylen_t len;\
-  type **elements; \
-} type ## _array; \
+typedef struct upb_norefcount_array upb_static_array;
+#define UPB_STATIC_ARRAY_INIT(arr, len) {{0 | UPB_DATA_FROZEN}, len, {._void=arr}}
+#define UPB_STATIC_ARRAY_PTR_TYPED_INIT(static_arr) {{&static_arr}}
+
+#define UPB_ARRAY_NULL_INITIALIZER {NULL}
+static const upb_arrayptr UPB_ARRAY_NULL = UPB_ARRAY_NULL_INITIALIZER;
+INLINE bool upb_array_isnull(upb_arrayptr a) { return a.base == NULL; }
+INLINE bool upb_array_ptreql(upb_arrayptr a1, upb_arrayptr a2) {
+  return a1.base == a2.base;
+}
 
-#define UPB_MSG_ARRAY(type) struct type ## _array
+#define UPB_MSG_ARRAYPTR(type) type ## _array
+#define UPB_DEFINE_MSG_ARRAY(type) \
+typedef struct { upb_arrayptr ptr; } UPB_MSG_ARRAYPTR(type); \
+INLINE upb_arraylen_t type ## _array_len(UPB_MSG_ARRAYPTR(type) a) { \
+  return upb_array_len(a.ptr); \
+} \
+INLINE type* type ## _array_get(UPB_MSG_ARRAYPTR(type) a, upb_arraylen_t elem) { \
+  return *(type**)_upb_array_getptr_raw(a.ptr, elem, sizeof(void*))._void; \
+}
 
 // Constructs a newly-allocated, reference-counted array which starts out
 // empty.  Caller owns one ref on it.
-upb_array *upb_array_new(void);
+upb_arrayptr upb_array_new(void);
 
 // Returns the current number of elements in the array.
-INLINE size_t upb_array_len(upb_array *a) {
-  return a->common.len;
+INLINE size_t upb_array_len(upb_arrayptr a) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED))
+    return a.refcounted->len;
+  else
+    return a.norefcount->len;
 }
 
 // INTERNAL-ONLY:
 // Frees the given message and releases references on members.
-void _upb_array_free(upb_array *a, struct upb_fielddef *f);
+void _upb_array_free(upb_arrayptr a, struct upb_fielddef *f);
 
 // INTERNAL-ONLY:
 // Returns a pointer to the given elem.
-INLINE union upb_value_ptr _upb_array_getptr(upb_array *a,
-                                             struct upb_fielddef *f,
-                                             upb_arraylen_t elem) {
-  size_t type_size = upb_type_info[f->type].size;
+INLINE union upb_value_ptr _upb_array_getptr_raw(upb_arrayptr a,
+                                                 upb_arraylen_t elem,
+                                                 size_t type_size) {
   union upb_value_ptr p;
-  p._void = &a->common.elements.uint8[elem * type_size];
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED))
+    p._void = &a.refcounted->elements.uint8[elem * type_size];
+  else
+    p._void = &a.norefcount->elements.uint8[elem * type_size];
   return p;
 }
 
-INLINE union upb_value upb_array_get(upb_array *a, struct upb_fielddef *f,
+INLINE union upb_value_ptr _upb_array_getptr(upb_arrayptr a,
+                                             struct upb_fielddef *f,
+                                             upb_arraylen_t elem) {
+  return _upb_array_getptr_raw(a, elem, upb_type_info[f->type].size);
+}
+
+INLINE union upb_value upb_array_get(upb_arrayptr a, struct upb_fielddef *f,
                                      upb_arraylen_t elem) {
   assert(elem < upb_array_len(a));
   return upb_value_read(_upb_array_getptr(a, f, elem), f->type);
@@ -421,33 +426,36 @@ INLINE union upb_value upb_array_get(upb_array *a, struct upb_fielddef *f,
 
 // The caller releases a ref on the given array, which it must previously have
 // owned a ref on.
-INLINE void upb_array_unref(upb_array *a, struct upb_fielddef *f) {
-  if(_upb_data_unref(&a->common.base)) _upb_array_free(a, f);
+INLINE void upb_array_unref(upb_arrayptr a, struct upb_fielddef *f) {
+  if(_upb_data_unref(a.base)) _upb_array_free(a, f);
 }
 
 #if 0
 // Returns an array to which caller owns a ref, and contains the same contents
 // as src.  The returned value may be a copy of src, if the requested flags
 // were incompatible with src's.
-INLINE upb_array *upb_array_getref(upb_array *src, int ref_flags);
+INLINE upb_arrayptr upb_array_getref(upb_arrayptr src, int ref_flags);
 
 // Sets the given element in the array to val.  The current length of the array
 // must be greater than elem.  If the field type is dynamic, the array will
 // take a ref on val and release a ref on what was previously in the array.
-INLINE void upb_array_set(upb_array *a, struct upb_fielddef *f, int elem,
+INLINE void upb_array_set(upb_arrayptr a, struct upb_fielddef *f, int elem,
                           union upb_value val);
 
 
 // Note that array_append will attempt to take a reference on the given value,
 // so to avoid a copy use append_default and get.
-INLINE void upb_array_append(upb_array *a, struct upb_fielddef *f,
+INLINE void upb_array_append(upb_arrayptr a, struct upb_fielddef *f,
                              union upb_value val);
-INLINE void upb_array_append_default(upb_array *a, struct upb_fielddef *f,
+INLINE void upb_array_append_default(upb_arrayptr a, struct upb_fielddef *f,
                              union upb_value val);
 #endif
 
-INLINE void upb_array_truncate(upb_array *a) {
-  a->common.len = 0;
+INLINE void upb_array_truncate(upb_arrayptr a) {
+  if(upb_data_hasflag(a.base, UPB_DATA_REFCOUNTED))
+    a.refcounted->len = 0;
+  else
+    a.norefcount->len = 0;
 }
 
 
diff --git a/src/upb_def.c b/src/upb_def.c
index 4f57407..24a57a6 100644
--- a/src/upb_def.c
+++ b/src/upb_def.c
@@ -364,12 +364,14 @@ static struct upb_enumdef *enumdef_new(google_protobuf_EnumDescriptorProto *ed,
 {
   struct upb_enumdef *e = malloc(sizeof(*e));
   upb_def_init(&e->base, UPB_DEF_ENUM, fqname);
-  int num_values = ed->set_flags.has.value ? ed->value->len : 0;
+  int num_values = ed->set_flags.has.value ?
+      google_protobuf_EnumValueDescriptorProto_array_len(ed->value) : 0;
   upb_strtable_init(&e->ntoi, num_values, sizeof(struct ntoi_ent));
   upb_inttable_init(&e->iton, num_values, sizeof(struct iton_ent));
 
   for(int i = 0; i < num_values; i++) {
-    google_protobuf_EnumValueDescriptorProto *value = ed->value->elements[i];
+    google_protobuf_EnumValueDescriptorProto *value =
+        google_protobuf_EnumValueDescriptorProto_array_get(ed->value, i);
     struct ntoi_ent ntoi_ent = {{value->name, 0}, value->number};
     struct iton_ent iton_ent = {{value->number, 0}, value->name};
     upb_strtable_insert(&e->ntoi, &ntoi_ent.e);
@@ -521,20 +523,22 @@ static void insert_message(struct upb_strtable *t,
   upb_strptr fqname = try_define(t, base, name, status);
   if(upb_string_isnull(fqname)) return;
 
-  int num_fields = d->set_flags.has.field ? d->field->len : 0;
+  int num_fields = d->set_flags.has.field ?
+      google_protobuf_FieldDescriptorProto_array_len(d->field) : 0;
   struct symtab_ent e;
   e.e.key = fqname;
 
   // Gather our list of fields, sorting if necessary.
   struct upb_fielddef **fielddefs = malloc(sizeof(*fielddefs) * num_fields);
   for (int i = 0; i < num_fields; i++) {
-    google_protobuf_FieldDescriptorProto *fd = d->field->elements[i];
+    google_protobuf_FieldDescriptorProto *fd =
+        google_protobuf_FieldDescriptorProto_array_get(d->field, i);
     fielddefs[i] = fielddef_new(fd);
   }
-  if(sort) fielddef_sort(fielddefs, d->field->len);
+  if(sort) fielddef_sort(fielddefs, num_fields);
 
   // Create the msgdef with that list of fields.
-  e.def = UPB_UPCAST(msgdef_new(fielddefs, d->field->len, fqname, status));
+  e.def = UPB_UPCAST(msgdef_new(fielddefs, num_fields, fqname, status));
 
   // Cleanup.
   for (int i = 0; i < num_fields; i++) fielddef_free(fielddefs[i]);
@@ -546,12 +550,12 @@ static void insert_message(struct upb_strtable *t,
 
   /* Add nested messages and enums. */
   if(d->set_flags.has.nested_type)
-    for(unsigned int i = 0; i < d->nested_type->len; i++)
-      insert_message(t, d->nested_type->elements[i], fqname, sort, status);
+    for(unsigned int i = 0; i < google_protobuf_DescriptorProto_array_len(d->nested_type); i++)
+      insert_message(t, google_protobuf_DescriptorProto_array_get(d->nested_type, i), fqname, sort, status);
 
   if(d->set_flags.has.enum_type)
-    for(unsigned int i = 0; i < d->enum_type->len; i++)
-      insert_enum(t, d->enum_type->elements[i], fqname, status);
+    for(unsigned int i = 0; i < google_protobuf_EnumDescriptorProto_array_len(d->enum_type); i++)
+      insert_enum(t, google_protobuf_EnumDescriptorProto_array_get(d->enum_type, i), fqname, status);
 
 error:
   // Free the ref we got from try_define().
@@ -618,12 +622,12 @@ static void addfd(struct upb_strtable *addto, struct upb_strtable *existingdefs,
   }
 
   if(fd->set_flags.has.message_type)
-    for(unsigned int i = 0; i < fd->message_type->len; i++)
-      insert_message(addto, fd->message_type->elements[i], pkg, sort, status);
+    for(unsigned int i = 0; i < google_protobuf_DescriptorProto_array_len(fd->message_type); i++)
+      insert_message(addto, google_protobuf_DescriptorProto_array_get(fd->message_type, i), pkg, sort, status);
 
   if(fd->set_flags.has.enum_type)
-    for(unsigned int i = 0; i < fd->enum_type->len; i++)
-      insert_enum(addto, fd->enum_type->elements[i], pkg, status);
+    for(unsigned int i = 0; i < google_protobuf_EnumDescriptorProto_array_len(fd->enum_type); i++)
+      insert_enum(addto, google_protobuf_EnumDescriptorProto_array_get(fd->enum_type, i), pkg, status);
 
   upb_string_unref(pkg);
 
@@ -686,8 +690,9 @@ struct upb_symtab *upb_symtab_new()
   upb_strtable_init(&s->psymtab, 16, sizeof(struct symtab_ent));
 
   // Add descriptor.proto types to private symtable so we can parse descriptors.
+  // We know there is only 1.
   google_protobuf_FileDescriptorProto *fd =
-      upb_file_descriptor_set->file->elements[0];  // We know there is only 1.
+      google_protobuf_FileDescriptorProto_array_get(upb_file_descriptor_set->file, 0);
   struct upb_status status = UPB_STATUS_INIT;
   addfd(&s->psymtab, &s->symtab, fd, false, &status);
   if(!upb_ok(&status)) {
@@ -782,8 +787,8 @@ void upb_symtab_addfds(struct upb_symtab *s,
 
     {  // Read lock scope
       upb_rwlock_rdlock(&s->lock);
-      for(uint32_t i = 0; i < fds->file->len; i++) {
-        addfd(&tmp, &s->symtab, fds->file->elements[i], true, status);
+      for(uint32_t i = 0; i < google_protobuf_FileDescriptorProto_array_len(fds->file); i++) {
+        addfd(&tmp, &s->symtab, google_protobuf_FileDescriptorProto_array_get(fds->file, i), true, status);
         if(!upb_ok(status)) {
           free_symtab(&tmp);
           upb_rwlock_unlock(&s->lock);
diff --git a/src/upb_text.c b/src/upb_text.c
index 225b344..3981715 100644
--- a/src/upb_text.c
+++ b/src/upb_text.c
@@ -92,7 +92,7 @@ static void printmsg(struct upb_text_printer *printer,
     if(!upb_msg_has(msg, f)) continue;
     union upb_value v = upb_msg_get(msg, f);
     if(upb_isarray(f)) {
-      upb_array *arr = v.arr;
+      upb_arrayptr arr = v.arr;
       for(uint32_t j = 0; j < upb_array_len(arr); j++) {
         union upb_value elem = upb_array_get(arr, f, j);
         printval(printer, elem, f, stream);
diff --git a/tests/test_vs_proto2.cc b/tests/test_vs_proto2.cc
index 63dc0f0..4356b05 100644
--- a/tests/test_vs_proto2.cc
+++ b/tests/test_vs_proto2.cc
@@ -25,7 +25,7 @@ void compare_arrays(const google::protobuf::Reflection *r,
                     upb_msg *upb_msg, struct upb_fielddef *upb_f)
 {
   ASSERT(upb_msg_has(upb_msg, upb_f));
-  upb_array *arr = upb_msg_get(upb_msg, upb_f).arr;
+  upb_arrayptr arr = upb_msg_get(upb_msg, upb_f).arr;
   ASSERT(upb_array_len(arr) == (upb_arraylen_t)r->FieldSize(proto2_msg, proto2_f));
   for(upb_arraylen_t i = 0; i < upb_array_len(arr); i++) {
     union upb_value v = upb_array_get(arr, upb_f, i);
diff --git a/tools/upbc.c b/tools/upbc.c
index b1fd0d9..1341800 100644
--- a/tools/upbc.c
+++ b/tools/upbc.c
@@ -158,8 +158,10 @@ static void write_h(struct upb_def *defs[], int num_defs, char *outfile_name,
     upb_strptr msg_name = upb_strdup(UPB_UPCAST(m)->fqname);
     to_cident(msg_name);
     fprintf(stream, "struct " UPB_STRFMT ";\n", UPB_STRARG(msg_name));
-    fprintf(stream, "typedef struct " UPB_STRFMT "\n    " UPB_STRFMT ";\n\n",
+    fprintf(stream, "typedef struct " UPB_STRFMT "\n    " UPB_STRFMT ";\n",
             UPB_STRARG(msg_name), UPB_STRARG(msg_name));
+    fprintf(stream, "UPB_DEFINE_MSG_ARRAY(" UPB_STRFMT ")\n\n",
+            UPB_STRARG(msg_name));
     upb_string_unref(msg_name);
   }
 
@@ -189,7 +191,7 @@ static void write_h(struct upb_def *defs[], int num_defs, char *outfile_name,
         upb_strptr type_name = upb_strdup(f->def->fqname);
         to_cident(type_name);
         if(f->label == UPB_LABEL(REPEATED)) {
-          fprintf(stream, "  UPB_MSG_ARRAY(" UPB_STRFMT ")* " UPB_STRFMT ";\n",
+          fprintf(stream, "  UPB_MSG_ARRAYPTR(" UPB_STRFMT ") " UPB_STRFMT ";\n",
                   UPB_STRARG(type_name), UPB_STRARG(f->name));
         } else {
           fprintf(stream, "  " UPB_STRFMT "* " UPB_STRFMT ";\n",
@@ -197,7 +199,7 @@ static void write_h(struct upb_def *defs[], int num_defs, char *outfile_name,
         }
         upb_string_unref(type_name);
       } else if(f->label == UPB_LABEL(REPEATED)) {
-        fprintf(stream, "  upb_array* " UPB_STRFMT ";\n", UPB_STRARG(f->name));
+        fprintf(stream, "  upb_arrayptr " UPB_STRFMT ";\n", UPB_STRARG(f->name));
       } else {
         static char* c_types[] = {
           "", "double", "float", "int64_t", "uint64_t", "int32_t", "uint64_t",
@@ -209,9 +211,7 @@ static void write_h(struct upb_def *defs[], int num_defs, char *outfile_name,
                 c_types[f->type], UPB_STRARG(f->name));
       }
     }
-    fputs("};\n", stream);
-    fprintf(stream, "UPB_DEFINE_MSG_ARRAY(" UPB_STRFMT ")\n\n",
-            UPB_STRARG(msg_name));
+    fputs("};\n\n", stream);
     upb_string_unref(msg_name);
   }
 
@@ -241,7 +241,7 @@ struct typetable_entry {
   struct array {
     int offset;
     int len;
-    upb_array *ptr;  /* So we can find it later. */
+    upb_arrayptr ptr;  /* So we can find it later. */
   } *arrays;
   int arrays_size, arrays_len;
 };
@@ -287,7 +287,7 @@ static void add_strings_from_msg(upb_msg *msg, struct upb_msgdef *md,
     if(!upb_msg_has(msg, f)) continue;
     union upb_value p = upb_msg_get(msg, f);
     if(upb_isarray(f)) {
-      upb_array *arr = p.arr;
+      upb_arrayptr arr = p.arr;
       for(uint32_t j = 0; j < upb_array_len(arr); j++)
         add_strings_from_value(upb_array_get(arr, f, j), f, t);
     } else {
@@ -345,7 +345,7 @@ static void add_submsgs(upb_msg *msg, struct upb_msgdef *md,
     union upb_value v = upb_msg_get(msg, f);
     if(upb_isarray(f)) {
       if(upb_isstring(f)) continue;  /* Handled by a different code-path. */
-      upb_array *arr = v.arr;
+      upb_arrayptr arr = v.arr;
 
       /* Add to our list of arrays for this type. */
       struct typetable_entry *arr_type_e =
@@ -475,11 +475,11 @@ static void write_message_c(upb_msg *msg, struct upb_msgdef *md,
       fprintf(stream, "};\n");
 
       int cum_offset = 0;
-      fprintf(stream, "static UPB_MSG_ARRAY(" UPB_STRFMT ") " UPB_STRFMT "_arrays[%d] = {\n",
-              UPB_STRARG(e->cident), UPB_STRARG(e->cident), e->arrays_len);
+      fprintf(stream, "static upb_static_array " UPB_STRFMT "_arrays[%d] = {\n",
+              UPB_STRARG(e->cident), e->arrays_len);
       for(int i = 0; i < e->arrays_len; i++) {
         struct array *arr = &e->arrays[i];
-        fprintf(stream, "  {.elements = &" UPB_STRFMT "_array_elems[%d], .len=%d},\n",
+        fprintf(stream, "  UPB_STATIC_ARRAY_INIT(&" UPB_STRFMT "_array_elems[%d], %d),\n",
                 UPB_STRARG(e->cident), cum_offset, arr->len);
         cum_offset += arr->len;
       }
@@ -515,7 +515,12 @@ static void write_message_c(upb_msg *msg, struct upb_msgdef *md,
           union upb_value val = upb_msg_get(msgdata, f);
           fprintf(stream, "    ." UPB_STRFMT " = ", UPB_STRARG(f->name));
           if(!upb_msg_has(msgdata, f)) {
-            if(upb_isstring(f) && !upb_isarray(f)) {
+            if(upb_isarray(f) && upb_issubmsg(f)) {
+              // This is gross and needs cleanup.
+              fputs("{UPB_ARRAY_NULL_INITIALIZER},   /* Not set. */", stream);
+            } else if(upb_isarray(f)) {
+              fputs("UPB_ARRAY_NULL_INITIALIZER,   /* Not set. */", stream);
+            } else if(upb_isstring(f)) {
               fputs("UPB_STRING_NULL_INITIALIZER,   /* Not set. */", stream);
             } else {
               fputs("0,   /* Not set. */", stream);
@@ -536,13 +541,13 @@ static void write_message_c(upb_msg *msg, struct upb_msgdef *md,
             assert(type_e);
             int arr_num = -1;
             for(int k = 0; k < type_e->arrays_len; k++) {
-              if(type_e->arrays[k].ptr == val.arr) {
+              if(upb_array_ptreql(type_e->arrays[k].ptr, val.arr)) {
                 arr_num = k;
                 break;
               }
             }
             assert(arr_num != -1);
-            fprintf(stream, "&" UPB_STRFMT "_arrays[%d],", UPB_STRARG(type_e->cident), arr_num);
+            fprintf(stream, "UPB_STATIC_ARRAY_PTR_TYPED_INIT(" UPB_STRFMT "_arrays[%d]),", UPB_STRARG(type_e->cident), arr_num);
           } else if(upb_issubmsg(f)) {
             /* Find this submessage in the list of msgs for that type. */
             struct typetable_entry  *type_e = get_or_insert_typeentry(&types, f);
@@ -625,10 +630,14 @@ void error(char *err, ...)
 
 void sort_fields_in_descriptor(google_protobuf_DescriptorProto *d)
 {
-  if(d->set_flags.has.field) upb_fielddef_sortfds(d->field->elements, d->field->len);
+  // XXX: modifying the array in place is totally not allowed.
+  if(d->set_flags.has.field) {
+    upb_fielddef_sortfds(_upb_array_getptr_raw(d->field.ptr, 0, 0)._void,
+                         google_protobuf_FieldDescriptorProto_array_len(d->field));
+  }
   if(d->set_flags.has.nested_type)
-    for(uint32_t i = 0; i < d->nested_type->len; i++)
-      sort_fields_in_descriptor(d->nested_type->elements[i]);
+    for(uint32_t i = 0; i < google_protobuf_DescriptorProto_array_len(d->nested_type); i++)
+      sort_fields_in_descriptor(google_protobuf_DescriptorProto_array_get(d->nested_type, i));
 }
 
 int main(int argc, char *argv[])
@@ -686,11 +695,11 @@ int main(int argc, char *argv[])
   // this scheme.
   //
   // If/when we ever make upbc more general, we'll have to revisit this.
-  for(uint32_t i = 0; i < fds->file->len; i++) {
-    google_protobuf_FileDescriptorProto *fd = fds->file->elements[i];
+  for(uint32_t i = 0; i < google_protobuf_FileDescriptorProto_array_len(fds->file); i++) {
+    google_protobuf_FileDescriptorProto *fd = google_protobuf_FileDescriptorProto_array_get(fds->file, i);
     if(!fd->set_flags.has.message_type) continue;
-    for(uint32_t j = 0; j < fd->message_type->len; j++)
-      sort_fields_in_descriptor(fd->message_type->elements[j]);
+    for(uint32_t j = 0; j < google_protobuf_DescriptorProto_array_len(fd->message_type); j++)
+      sort_fields_in_descriptor(google_protobuf_DescriptorProto_array_get(fd->message_type, j));
   }
 
   /* Emit output files. */