On 1/7/21 11:47 AM, Jakub Jelinek wrote:
In GCC10 cp_walk_subtrees has been changed to walk template arguments.
As the following testcase, that changed the mangling of some functions.
Argh.
I believe the previous behavior that find_abi_tags_r doesn't recurse into
template args has been the correct one, but setting *walk_subtrees = 0
for the types and handling the types subtree walking manually in
find_abi_tags_r looks too hard, there are a lot of subtrees and details what
should and shouldn't be walked, both in tree.c (walk_type_fields there,
which is static) and in cp_walk_subtrees itself.
The following patch abuses the fact that *walk_subtrees is an int to
tell cp_walk_subtrees it shouldn't walk the template args.
Another option would be to have two separate cp_walk_subtrees-like
callbacks, one that wouldn't walk into template args and the other
that would and then would tail call the other one, and
cp_walk_tree_without_duplicates but call walk_tree_1 directly or use
some other macro.
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?
Jason
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
