On Wed, Jun 24, 2026 at 11:48:02AM +0200, Georg-Johann Lay wrote:
> In mangle.cc there is:
>
> /* Return an identifier for a construction vtable group. TYPE is
> the most derived class in the hierarchy; BINFO is the base
> subobject for which this construction vtable group will be used.
>
> This mangling isn't part of the ABI specification; in the ABI
> specification, the vtable group is dumped in the same COMDAT as the
> main vtable, and is referenced only from that vtable, so it doesn't
> need an external name. For binary formats without COMDAT sections,
> though, we need external names for the vtable groups.
>
> We use the production
>
> <special-name> ::= CT <type> <offset number> _ <base type> */
>
> tree
> mangle_ctor_vtbl_for_type (const tree type, const tree binfo)
> {
> tree result;
>
> start_mangling (type);
>
> write_string ("_Z");
> write_string ("TC");
>
>
> So it seems there is an obvious typo in the comment which says "CT"
> but the actual mangling is "TC".
>
> If ok I would apply the following patch to trunk:
>
>
> diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc
> index 8c67b67b197..d368359dccd 100644
> --- a/gcc/cp/mangle.cc
> +++ b/gcc/cp/mangle.cc
> @@ -5131,7 +5131,7 @@ mangle_decomp (const tree decl, vec<tree> &decls)
>
> We use the production
>
> - <special-name> ::= CT <type> <offset number> _ <base type> */
> + <special-name> ::= TC <type> <offset number> _ <base type> */
Looks good, but it will need a ChangeLog entry.
Marek
