free-lang-data: Remove C++ annotations [PR123837]

As mentioned in the PR and reproduced on the testcase, we ICE during
LTO streaming because C++ annotation arguments can contain trees LTO
streaming doesn't handle.
We don't really need annotations when the FE is done with the whole
TU, annotations are always TU local and not exposed to the rest and
used in consteval only stuff, so the following patch just removes
all annotations at free-lang-data time.

2026-01-28  Jakub Jelinek  <jakub@redhat.com>

	PR c++/123837
	* ipa-free-lang-data.cc (find_decls_types_r): Remove C++ annotations
	from {DECL,TYPE}_ATRIBUTES.

	* g++.dg/reflect/annotations9.C: New test.

diff --git a/gcc/ipa-free-lang-data.cc b/gcc/ipa-free-lang-data.cc
index edc4f1aed8111bd3f11593aceca41fbbdc9a6648..f32563fdd22d07fbb438174fe9919ce17515d84a 100644 (file)
--- a/gcc/ipa-free-lang-data.cc
+++ b/gcc/ipa-free-lang-data.cc
@@ -730,6 +730,10 @@ find_decls_types_r (tree *tp, int *ws, void *data)
       if (TREE_CODE (t) != TYPE_DECL)
        fld_worklist_push (DECL_INITIAL (t), fld);
 
+      /* Remove C++ annotations, those aren't needed for LTO and contain
+        trees we sometimes can't stream.  */
+      DECL_ATTRIBUTES (t)
+       = remove_attribute ("annotation ", DECL_ATTRIBUTES (t));
       fld_worklist_push (DECL_ATTRIBUTES (t), fld);
       fld_worklist_push (DECL_ABSTRACT_ORIGIN (t), fld);
 
@@ -763,6 +767,10 @@ find_decls_types_r (tree *tp, int *ws, void *data)
        fld_worklist_push (TYPE_CACHED_VALUES (t), fld);
       fld_worklist_push (TYPE_SIZE (t), fld);
       fld_worklist_push (TYPE_SIZE_UNIT (t), fld);
+      /* Remove C++ annotations, those aren't needed for LTO and contain
+        trees we sometimes can't stream.  */
+      TYPE_ATTRIBUTES (t)
+       = remove_attribute ("annotation ", TYPE_ATTRIBUTES (t));
       fld_worklist_push (TYPE_ATTRIBUTES (t), fld);
       fld_worklist_push (TYPE_POINTER_TO (t), fld);
       fld_worklist_push (TYPE_REFERENCE_TO (t), fld);

diff --git a/gcc/testsuite/g++.dg/reflect/annotations9.C b/gcc/testsuite/g++.dg/reflect/annotations9.C
new file mode 100644 (file)
index 0000000..32078f2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/reflect/annotations9.C
@@ -0,0 +1,14 @@
+// PR c++/123837
+// { dg-do compile { target c++26 } }
+// { dg-additional-options "-freflection" }
+// { dg-additional-options "-flto" { target lto } }
+
+struct A {};
+[[=A {}]] int a {};
+struct [[=A {}]] B { int b; };
+B b {};
+
+int
+main ()
+{
+}