> Tested x86_64-pc-linux-gnu. Does this look good, or do we want to factor the
> flag clearing into a symtab_node counterpart to cgraph_node::reset?
>
> -- 8< --
>
> In 107897, by the time we are looking at the mangling clash, the
> alias has already been removed from the symbol table by analyze_functions,
> so we can't look at n->cpp_implicit_alias. So just assume that it's an
> alias if it's internal.
>
> In 108887 the problem is that removing the mangling alias from the symbol
> table confuses analyze_functions, because it ended up as first_analyzed
> somehow, so it becomes a dangling pointer. Fixed by clearing various flags
> to neutralize the alias.
>
> PR c++/107897
> PR c++/108887
>
> gcc/cp/ChangeLog:
>
> * decl2.cc (record_mangling): Improve symbol table handling.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/concepts-lambda3.C: Use -flto if supported.
> * g++.dg/cpp0x/lambda/lambda-mangle7.C: New test.
> ---
> gcc/cp/decl2.cc | 25 +++++--
> .../g++.dg/cpp0x/lambda/lambda-mangle7.C | 70 +++++++++++++++++++
> gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C | 1 +
> 3 files changed, 91 insertions(+), 5 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
>
> diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
> index 387e24542cd..e6e58b08de4 100644
> --- a/gcc/cp/decl2.cc
> +++ b/gcc/cp/decl2.cc
> @@ -4742,15 +4742,30 @@ record_mangling (tree decl, bool need_warning)
> = mangled_decls->find_slot_with_hash (id, IDENTIFIER_HASH_VALUE (id),
> INSERT);
>
> - /* If this is already an alias, remove the alias, because the real
> + /* If this is already an alias, cancel the alias, because the real
> decl takes precedence. */
> if (*slot && DECL_ARTIFICIAL (*slot) && DECL_IGNORED_P (*slot))
> - if (symtab_node *n = symtab_node::get (*slot))
> - if (n->cpp_implicit_alias)
> + {
> + if (symtab_node *n = symtab_node::get (*slot))
> {
> - n->remove ();
> - *slot = NULL_TREE;
> + if (n->cpp_implicit_alias)
> + {
> + /* Actually removing the node isn't safe if other code is already
> + holding a pointer to it, so just neutralize it. */
> + n->remove_from_same_comdat_group ();
> + n->analyzed = false;
> + n->definition = false;
> + n->alias = false;
> + n->cpp_implicit_alias = false;
We have n->reset () for that which is used in similar situation when
frontends overwrites extern inline function by its different offline
implementation.
reset doesn't call remove_from_same_comdat_group probably because it was
never used on anything in comdat group. So I think it would make sense
to call n->reset() here and add remove_from_same_comdat_group into that.
OK with that change.
Honza
> + }
> }
> + else
> + /* analyze_functions might have already removed the alias from the
> + symbol table if it's internal. */
> + gcc_checking_assert (!TREE_PUBLIC (*slot));
> +
> + *slot = NULL_TREE;
> + }
>
> if (!*slot)
> *slot = decl;
> diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
> b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
> new file mode 100644
> index 00000000000..c7946a2be08
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
> @@ -0,0 +1,70 @@
> +// PR c++/108887
> +// { dg-do compile { target c++11 } }
> +
> +template <int __v> struct integral_constant {
> + static constexpr int value = __v;
> +};
> +using false_type = integral_constant<false>;
> +template <bool, bool, typename...> struct __result_of_impl;
> +template <typename _Functor, typename... _ArgTypes>
> +struct __result_of_impl<false, false, _Functor, _ArgTypes...> {
> + typedef decltype(0) type;
> +};
> +template <typename... _ArgTypes>
> +struct __invoke_result
> + : __result_of_impl<false_type::value, false_type::value, _ArgTypes...>
> {};
> +template <typename, typename _Fn, typename... _Args>
> +void __invoke_impl(_Fn __f, _Args... __args) {
> + __f(__args...);
> +}
> +template <typename, typename _Callable, typename... _Args>
> +void __invoke_r(_Callable __fn, _Args... __args) {
> + using __result = __invoke_result<_Args...>;
> + using __type = typename __result::type;
> + __invoke_impl<__type>(__fn, __args...);
> +}
> +struct QString {
> + QString(const char *);
> +};
> +template <typename> class function;
> +template <typename _Functor> struct _Base_manager {
> + static _Functor _M_get_pointer(int) { __builtin_abort (); }
> +};
> +template <typename, typename> class _Function_handler;
> +template <typename _Res, typename _Functor, typename... _ArgTypes>
> +struct _Function_handler<_Res(_ArgTypes...), _Functor> {
> + using _Base = _Base_manager<_Functor>;
> + static _Res _M_invoke(const int &__functor, _ArgTypes &&...__args) {
> + auto __trans_tmp_1 = _Base::_M_get_pointer(__functor);
> + __invoke_r<_Res>(__trans_tmp_1, __args...);
> + }
> +};
> +template <typename _Res, typename... _ArgTypes>
> +struct function<_Res(_ArgTypes...)> {
> + template <typename _Functor>
> + using _Handler = _Function_handler<_Res(_ArgTypes...), _Functor>;
> + template <typename _Functor> function(_Functor) {
> + using _My_handler = _Handler<_Functor>;
> + _M_invoker = _My_handler::_M_invoke;
> + }
> + using _Invoker_type = _Res (*)(const int &, _ArgTypes &&...);
> + _Invoker_type _M_invoker;
> +};
> +struct QRegularExpression {
> + QRegularExpression(QString);
> +};
> +struct AbstractAccount {
> + void get(function<void(AbstractAccount *)>,
> + function<void(AbstractAccount *)>);
> +};
> +struct AbstractTimelineModel {
> + AbstractAccount m_account;
> +};
> +struct LinkPaginationTimelineModel : AbstractTimelineModel {
> + void fillTimeline();
> +};
> +void LinkPaginationTimelineModel::fillTimeline() {
> + [] {};
> + m_account.get([](AbstractAccount *) { static QRegularExpression re(""); },
> + [](AbstractAccount *) {});
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
> b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
> index 291e451ca1a..a7cb6c5dece 100644
> --- a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
> +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
> @@ -1,4 +1,5 @@
> // { dg-do run { target c++20 } }
> +// { dg-additional-options "-flto" { target lto } } (PR107897)
>
> template<typename T>
> concept C1 = __is_same_as(T, int)
>
> base-commit: 4f181f9c7ee3efc509d185fdfda33be9018f1611
> --
> 2.31.1
>
