[PATCH] i386: Set TREE_PUBLIC on TYPE_NAME of __va_list_tag [PR124565]

[Jakub Jelinek]

Hi!

 module;
 #include <cstdarg>
 export module pr124565;
 export namespace std {
   using std::va_list;
 }
fails on alpha-linux with -fmodules:
pr124565.cc:5:14: error: exporting ‘typedef __gnuc_va_list va_list’ that does 
not have external linkage
<built-in>: note: ‘typedef struct __va_list_tag __va_list_tag’ declared here 
with internal linkage

It doesn't fail on x86_64-linux because there va_list is __va_list_tag[]
(i.e. array type), while on alpha-linux it is __va_list_tag itself; and the
module code calls decl_linkage on it and returns lk_internal for C++11 and
later.

Now, decl_linkage on x86_64-linux on __va_list_tag directly also returns
incorrectly lk_internal, and as I have no way to test alpha, I've
bootstrapped/regtested on x86_64-linux and i686-linux the following patch.

IMHO it is still desirable even there even when it is just a latent issue.

Ok for trunk?

2026-03-19  Jakub Jelinek  <ja...@redhat.com>

        PR target/124565
        * config/i386/i386.cc (ix86_build_builtin_va_list_64): Set TREE_PUBLIC
        on type_decl.

--- gcc/config/i386/i386.cc.jj  2026-03-04 22:38:02.421879010 +0100
+++ gcc/config/i386/i386.cc     2026-03-19 09:30:37.446207733 +0100
@@ -4564,6 +4564,7 @@ ix86_build_builtin_va_list_64 (void)
   DECL_CHAIN (f_gpr) = f_fpr;
   DECL_CHAIN (f_fpr) = f_ovf;
   DECL_CHAIN (f_ovf) = f_sav;
+  TREE_PUBLIC (type_decl) = 1;
 
   layout_type (record);
 

        Jakub