3 files changed, 45 insertions, 0 deletions
diff --git a/gcc/c/c-lang.cc b/gcc/c/c-lang.cc
index ddfd3e8..ff6633e 100644
--- a/gcc/c/c-lang.cc
+++ b/gcc/c/c-lang.cc
@@ -63,6 +63,15 @@ c_get_sarif_source_language (const char *)
   return "c";
 }
 
+/* Implement c-family hook to register language-specific features for
+   __has_{feature,extension}.  */
+
+void
+c_family_register_lang_features ()
+{
+  c_register_features ();
+}
+
 #if CHECKING_P
 
 namespace selftest {
diff --git a/gcc/c/c-objc-common.cc b/gcc/c/c-objc-common.cc
index c8f49aa..53eda7f 100644
--- a/gcc/c/c-objc-common.cc
+++ b/gcc/c/c-objc-common.cc
@@ -34,6 +34,39 @@ along with GCC; see the file COPYING3.  If not see
 static bool c_tree_printer (pretty_printer *, text_info *, const char *,
 			    int, bool, bool, bool, bool *, const char **);
 
+/* Info for C language features which can be queried through
+   __has_{feature,extension}.  */
+
+struct c_feature_info
+{
+  const char *ident;
+  const int *enable_flag;
+};
+
+static const c_feature_info c_feature_table[] =
+{
+  { "c_alignas", &flag_isoc11 },
+  { "c_alignof", &flag_isoc11 },
+  { "c_atomic", &flag_isoc11 },
+  { "c_generic_selections", &flag_isoc11 },
+  { "c_static_assert", &flag_isoc11 },
+  { "c_thread_local", &flag_isoc11 },
+  { "cxx_binary_literals", &flag_isoc23 }
+};
+
+/* Register features specific to the C language.  */
+
+void
+c_register_features ()
+{
+  for (unsigned i = 0; i < ARRAY_SIZE (c_feature_table); i++)
+    {
+      const c_feature_info *info = c_feature_table + i;
+      const bool feat_p = !info->enable_flag || *info->enable_flag;
+      c_common_register_feature (info->ident, feat_p);
+    }
+}
+
 bool
 c_missing_noreturn_ok_p (tree decl)
 {
diff --git a/gcc/c/c-objc-common.h b/gcc/c/c-objc-common.h
index ede451c..63aff70 100644
--- a/gcc/c/c-objc-common.h
+++ b/gcc/c/c-objc-common.h
@@ -21,6 +21,9 @@ along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_C_OBJC_COMMON
 #define GCC_C_OBJC_COMMON
 
+/* Implemented in c-objc-common.cc.  */
+extern void c_register_features ();
+
 /* Lang hooks that are shared between C and ObjC are defined here.  Hooks
    specific to C or ObjC go in c-lang.cc and objc/objc-lang.cc, respectively.  */