Fixed LTO-only linker error in upb linker arrays.

Also removed a sanitizer warning on non-Clang compilers.

Fixes: #21021
PiperOrigin-RevId: 748395156

Author: haberman

upb/mini_table/extension_registry.c

@@ -82,7 +82,7 @@ upb_ExtensionRegistryStatus upb_ExtensionRegistry_AddArray(
 
 #ifdef UPB_LINKARR_DECLARE
 
-UPB_LINKARR_DECLARE(upb_AllExts, upb_MiniTableExtension);
+UPB_LINKARR_DECLARE(upb_AllExts, const upb_MiniTableExtension);
 
 bool upb_ExtensionRegistry_AddAllLinkedExtensions(upb_ExtensionRegistry* r) {
   const upb_MiniTableExtension* start = UPB_LINKARR_START(upb_AllExts);

upb/port/def.inc

@@ -467,6 +467,12 @@ Error, UINTPTR_MAX is undefined
 
 #undef UPB_IS_GOOGLE3
 
+#ifdef __clang__
+#define UPB_NO_SANITIZE_ADDRESS __attribute__((no_sanitize("address")))
+#else
+#define UPB_NO_SANITIZE_ADDRESS
+#endif
+
 // Linker arrays combine elements from multiple translation units into a single
 // array that can be iterated over at runtime.
 //
@@ -493,28 +499,28 @@ Error, UINTPTR_MAX is undefined
 
 #if defined(__ELF__) || defined(__wasm__)
 
-#define UPB_LINKARR_APPEND(name)                          \
-  __attribute__((retain, used, section("linkarr_" #name), \
-                 no_sanitize("address")))
-#define UPB_LINKARR_DECLARE(name, type)     \
-  extern type const __start_linkarr_##name; \
-  extern type const __stop_linkarr_##name;  \
+#define UPB_LINKARR_APPEND(name) \
+  __attribute__((retain, used,   \
+                 section("linkarr_" #name))) UPB_NO_SANITIZE_ADDRESS
+#define UPB_LINKARR_DECLARE(name, type) \
+  extern type __start_linkarr_##name;   \
+  extern type __stop_linkarr_##name;    \
   UPB_LINKARR_APPEND(name) type UPB_linkarr_internal_empty_##name[1]
 #define UPB_LINKARR_START(name) (&__start_linkarr_##name)
 #define UPB_LINKARR_STOP(name) (&__stop_linkarr_##name)
 
 #elif defined(__MACH__)
 
 /* As described in: https://stackoverflow.com/a/22366882 */
-#define UPB_LINKARR_APPEND(name)                              \
-  __attribute__((retain, used, section("__DATA,__la_" #name), \
-                 no_sanitize("address")))
-#define UPB_LINKARR_DECLARE(name, type)           \
-  extern type const __start_linkarr_##name __asm( \
-      "section$start$__DATA$__la_" #name);        \
-  extern type const __stop_linkarr_##name __asm(  \
-      "section$end$__DATA$"                       \
-      "__la_" #name);                             \
+#define UPB_LINKARR_APPEND(name) \
+  __attribute__((retain, used,   \
+                 section("__DATA,__la_" #name))) UPB_NO_SANITIZE_ADDRESS
+#define UPB_LINKARR_DECLARE(name, type)     \
+  extern type __start_linkarr_##name __asm( \
+      "section$start$__DATA$__la_" #name);  \
+  extern type __stop_linkarr_##name __asm(  \
+      "section$end$__DATA$"                 \
+      "__la_" #name);                       \
   UPB_LINKARR_APPEND(name) type UPB_linkarr_internal_empty_##name[1]
 #define UPB_LINKARR_START(name) (&__start_linkarr_##name)
 #define UPB_LINKARR_STOP(name) (&__stop_linkarr_##name)
@@ -530,7 +536,7 @@ Error, UINTPTR_MAX is undefined
 // not work on MSVC.
 #define UPB_LINKARR_APPEND(name)         \
   __declspec(allocate("la_" #name "$j")) \
-  __attribute__((retain, used, no_sanitize("address")))
+  __attribute__((retain, used)) UPB_NO_SANITIZE_ADDRESS
 #define UPB_LINKARR_DECLARE(name, type)                               \
   __declspec(allocate("la_" #name "$a")) type __start_linkarr_##name; \
   __declspec(allocate("la_" #name "$z")) type __stop_linkarr_##name;  \