On Wed, Feb 20, 2019 at 2:58 AM Jason Merrill <ja...@redhat.com> wrote:
>
> A type in an anonymous namespace can never be merged with one from
> another translation unit, so a member of such a type is always its own
> prevailing decl.
>
> I don't really understand the LTO concept of prevailing decl, or why we don't
> get here if the destructor is defined, but this seems reasonable and fixes the
> bug.
We're probably not supposed to end up here but get the "precomputed"
prevailing decl from symtab merging. Honza should know more precisely.
The resolution file does have an entry for the UNDEF destructor.
Does this make the testcase invalid btw? There's no way another TU
can inject a definition into the same anonymous namespace, no?
And does the point of instantiation really determine the containing
namespace of the class?
Richard.
>
> Tested x86_64-pc-linux-gnu. OK for trunk?
>
> * lto-symtab.c (lto_symtab_prevailing_virtual_decl): Return early
> for a type in an anonymous namespace.
> ---
> gcc/lto/lto-symtab.c | 8 ++++++--
> gcc/testsuite/g++.dg/lto/pr88049_0.C | 16 ++++++++++++++++
> gcc/lto/ChangeLog | 6 ++++++
> 3 files changed, 28 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/lto/pr88049_0.C
>
> diff --git a/gcc/lto/lto-symtab.c b/gcc/lto/lto-symtab.c
> index 22da4c78b8c..343915c3cec 100644
> --- a/gcc/lto/lto-symtab.c
> +++ b/gcc/lto/lto-symtab.c
> @@ -1085,8 +1085,12 @@ lto_symtab_prevailing_virtual_decl (tree decl)
> {
> if (DECL_ABSTRACT_P (decl))
> return decl;
> - gcc_checking_assert (!type_in_anonymous_namespace_p (DECL_CONTEXT (decl))
> - && DECL_ASSEMBLER_NAME_SET_P (decl));
> +
> + if (type_in_anonymous_namespace_p (DECL_CONTEXT (decl)))
> + /* There can't be any other declarations. */
> + return decl;
> +
> + gcc_checking_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
>
> symtab_node *n = symtab_node::get_for_asmname
> (DECL_ASSEMBLER_NAME (decl));
> diff --git a/gcc/testsuite/g++.dg/lto/pr88049_0.C
> b/gcc/testsuite/g++.dg/lto/pr88049_0.C
> new file mode 100644
> index 00000000000..7ac3618c2c8
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/lto/pr88049_0.C
> @@ -0,0 +1,16 @@
> +// PR c++/88049
> +// { dg-lto-do link }
> +// { dg-lto-options {{ -flto -O2 -w }} }
> +// { dg-extra-ld-options -r }
> +
> +template <typename> class a;
> +class b {};
> +template <typename e> a<e> d(char);
> +template <typename> class a : public b {
> +public:
> + virtual ~a();
> +};
> +namespace {
> + class f;
> + b c = d<f>(int());
> +} // namespace
> diff --git a/gcc/lto/ChangeLog b/gcc/lto/ChangeLog
> index 6b183df3b0f..71a2a109e64 100644
> --- a/gcc/lto/ChangeLog
> +++ b/gcc/lto/ChangeLog
> @@ -1,3 +1,9 @@
> +2019-02-18 Jason Merrill <ja...@redhat.com>
> +
> + PR c++/88049 - ICE with undefined destructor and anon namespace.
> + * lto-symtab.c (lto_symtab_prevailing_virtual_decl): Return early
> + for a type in an anonymous namespace.
> +
> 2019-01-09 Sandra Loosemore <san...@codesourcery.com>
>
> PR other/16615
>
> base-commit: 79ae32275d4a19a1fc6ffebec9ac15a8c94b0b8f
> --
> 2.20.1
>
