diff --git a/libc/include/link.h b/libc/include/link.h
index bd430f5..a0a3d60 100644
--- a/libc/include/link.h
+++ b/libc/include/link.h
@@ -44,41 +44,41 @@
 
 struct dl_phdr_info {
   ElfW(Addr) dlpi_addr;
-  const char* dlpi_name;
-  const ElfW(Phdr)* dlpi_phdr;
+  const char* _Nullable dlpi_name;
+  const ElfW(Phdr)* _Nullable dlpi_phdr;
   ElfW(Half) dlpi_phnum;
 
   // These fields were added in Android R.
   unsigned long long dlpi_adds;
   unsigned long long dlpi_subs;
   size_t dlpi_tls_modid;
-  void* dlpi_tls_data;
+  void* _Nullable dlpi_tls_data;
 };
 
 #if defined(__arm__)
-int dl_iterate_phdr(int (*__callback)(struct dl_phdr_info*, size_t, void*), void* __data) __INTRODUCED_IN(21);
+int dl_iterate_phdr(int (* _Nonnull __callback)(struct dl_phdr_info* _Nonnull, size_t, void* _Nullable), void* _Nullable __data) __INTRODUCED_IN(21);
 #else
-int dl_iterate_phdr(int (*__callback)(struct dl_phdr_info*, size_t, void*), void* __data);
+int dl_iterate_phdr(int (* _Nonnull __callback)(struct dl_phdr_info* _Nonnull, size_t, void*_Nullable ), void* _Nullable __data);
 #endif
 
 #ifdef __arm__
 typedef uintptr_t _Unwind_Ptr;
-_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr, int*);
+_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr, int* _Nonnull);
 #endif
 
 /* Used by the dynamic linker to communicate with the debugger. */
 struct link_map {
   ElfW(Addr) l_addr;
-  char* l_name;
-  ElfW(Dyn)* l_ld;
-  struct link_map* l_next;
-  struct link_map* l_prev;
+  char* _Nullable l_name;
+  ElfW(Dyn)* _Nullable l_ld;
+  struct link_map* _Nullable l_next;
+  struct link_map* _Nullable l_prev;
 };
 
 /* Used by the dynamic linker to communicate with the debugger. */
 struct r_debug {
   int32_t r_version;
-  struct link_map* r_map;
+  struct link_map* _Nullable r_map;
   ElfW(Addr) r_brk;
   enum {
     RT_CONSISTENT,