https://gcc.gnu.org/g:0e485b8c85c31856b9f7c91015ac94874b100bd4
commit r15-7504-g0e485b8c85c31856b9f7c91015ac94874b100bd4
Author: Nathaniel Shead <nathanielosh...@gmail.com>
Date: Wed Feb 12 23:07:43 2025 +1100
c++: Constrain visibility for CNTTPs with internal types [PR118849]
While looking into PR118846 I noticed that we don't currently constrain
the linkage of functions involving CNTTPs of internal-linkage types. It
seems to me that this would be sensible to do.
PR c++/118849
gcc/cp/ChangeLog:
* decl2.cc (min_vis_expr_r): Constrain visibility according to
the type of decl_constant_var_p decls.
gcc/testsuite/ChangeLog:
* g++.dg/template/linkage6.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
Diff:
---
gcc/cp/decl2.cc | 4 +++-
gcc/testsuite/g++.dg/template/linkage6.C | 13 +++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 593dcaa4e2de..aa9ebca12f8f 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -2814,7 +2814,9 @@ min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void
*data)
/* The ODR allows definitions in different TUs to refer to distinct
constant variables with internal or no linkage, so such a reference
shouldn't affect visibility (PR110323). FIXME but only if the
- lvalue-rvalue conversion is applied. */;
+ lvalue-rvalue conversion is applied. We still want to restrict
+ visibility according to the type of the declaration however. */
+ tpvis = type_visibility (TREE_TYPE (t));
else if (! TREE_PUBLIC (t))
tpvis = VISIBILITY_ANON;
else
diff --git a/gcc/testsuite/g++.dg/template/linkage6.C
b/gcc/testsuite/g++.dg/template/linkage6.C
new file mode 100644
index 000000000000..b86c986568f8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/linkage6.C
@@ -0,0 +1,13 @@
+// PR c++/118849
+// { dg-do compile { target c++20 } }
+// { dg-final { scan-assembler-not "(weak|glob)\[^\n\]*_Z" { xfail
powerpc-*-aix* } } }
+
+namespace {
+ struct A {};
+}
+
+template <auto Q> void f() { }
+
+int main() {
+ f<A{}>();
+}
