On Fri, Jan 08, 2021 at 02:22:59PM -0500, Jason Merrill wrote:
> I like the idea to use *walk_subtrees to distinguish between walking
> syntactic subtrees and walking type-identity subtrees. But it should be
> more general; how does this look to you?
LGTM, thanks.
> diff --git a/gcc/cp/class.c b/gcc/cp/class.c
> index c41ac7deefe..00c0dba0a55 100644
> --- a/gcc/cp/class.c
> +++ b/gcc/cp/class.c
> @@ -1507,6 +1507,10 @@ mark_or_check_tags (tree t, tree *tp, abi_tag_data *p,
> bool val)
> static tree
> find_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
> {
> + if (TYPE_P (*tp) && *walk_subtrees == 1)
> + /* Tell cp_walk_subtrees to look though typedefs. */
> + *walk_subtrees = 2;
> +
> if (!OVERLOAD_TYPE_P (*tp))
> return NULL_TREE;
>
> @@ -1527,6 +1531,10 @@ find_abi_tags_r (tree *tp, int *walk_subtrees, void
> *data)
> static tree
> mark_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
> {
> + if (TYPE_P (*tp) && *walk_subtrees == 1)
> + /* Tell cp_walk_subtrees to look though typedefs. */
> + *walk_subtrees = 2;
> +
> if (!OVERLOAD_TYPE_P (*tp))
> return NULL_TREE;
>
> diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
> index b10671091b5..b087753cfba 100644
> --- a/gcc/cp/decl2.c
> +++ b/gcc/cp/decl2.c
> @@ -2358,9 +2358,6 @@ min_vis_r (tree *tp, int *walk_subtrees, void *data)
> int this_vis = VISIBILITY_DEFAULT;
> if (! TYPE_P (*tp))
> *walk_subtrees = 0;
> - else if (typedef_variant_p (*tp))
> - /* Look through typedefs despite cp_walk_subtrees. */
> - this_vis = type_visibility (DECL_ORIGINAL_TYPE (TYPE_NAME (*tp)));
> else if (OVERLOAD_TYPE_P (*tp)
> && !TREE_PUBLIC (TYPE_MAIN_DECL (*tp)))
> {
> @@ -2379,6 +2376,10 @@ min_vis_r (tree *tp, int *walk_subtrees, void *data)
> if (this_vis > *vis_p)
> *vis_p = this_vis;
>
> + /* Tell cp_walk_subtrees to look through typedefs. */
> + if (*walk_subtrees == 1)
> + *walk_subtrees = 2;
> +
> return NULL;
> }
>
> diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
> index 82027cc9abf..c536eb581a7 100644
> --- a/gcc/cp/tree.c
> +++ b/gcc/cp/tree.c
> @@ -5146,16 +5146,26 @@ cp_walk_subtrees (tree *tp, int *walk_subtrees_p,
> walk_tree_fn func,
>
> if (TYPE_P (*tp))
> {
> - /* Walk into template args without looking through typedefs. */
> - if (tree ti = TYPE_TEMPLATE_INFO_MAYBE_ALIAS (*tp))
> - WALK_SUBTREE (TI_ARGS (ti));
> - /* Don't look through typedefs; walk_tree_fns that want to look through
> - typedefs (like min_vis_r) need to do that themselves. */
> - if (typedef_variant_p (*tp))
> + /* If *WALK_SUBTREES_P is 1, we're interested in the syntactic form of
> + the argument, so don't look through typedefs, but do walk into
> + template arguments for alias templates (and non-typedefed classes).
> +
> + If *WALK_SUBTREES_P > 1, we're interested in type identity or
> + equivalence, so look through typedefs, ignoring template arguments for
> + alias templates, and walk into template args of classes.
> +
> + See find_abi_tags_r for an example of setting *WALK_SUBTREES_P to 2
> + when that's the behavior the walk_tree_fn wants. */
> + if (*walk_subtrees_p == 1 && typedef_variant_p (*tp))
> {
> + if (tree ti = TYPE_ALIAS_TEMPLATE_INFO (*tp))
> + WALK_SUBTREE (TI_ARGS (ti));
> *walk_subtrees_p = 0;
> return NULL_TREE;
> }
> +
> + if (tree ti = TYPE_TEMPLATE_INFO (*tp))
> + WALK_SUBTREE (TI_ARGS (ti));
> }
>
> /* Not one of the easy cases. We must explicitly go through the
Jakub
