Hi,
On Wed, Oct 26 2022, Alexander Monakov wrote:
> When upgrading TLS access model based on optimized symbol visibility
> status, we attempted to assert that recomputing the model would not
> weaken it. It turns out that C, C++, and Fortran front-ends all can
> (unintentionally) assign a stronger model than what can be derived
> from the declaration.
If you believe that FEs assign a wrong model sometimes (that is my
impression after reading your bugzilla comments), please open bugs for
those cases.
>
> Let's act conservatively instead of asserting, at least as long as
> such pre-existing issues remain.
>
> gcc/ChangeLog:
>
> PR other/107353
> * ipa-visibility.cc (function_and_variable_visibility):
> Conditionally upgrade TLS model instead of asserting.
The patch is OK (assuming it passes bootstrap&testing).
Thanks,
Martin
> ---
> gcc/ipa-visibility.cc | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/ipa-visibility.cc b/gcc/ipa-visibility.cc
> index 3ed2b7cf6..238f7eb84 100644
> --- a/gcc/ipa-visibility.cc
> +++ b/gcc/ipa-visibility.cc
> @@ -886,8 +886,12 @@ function_and_variable_visibility (bool whole_program)
> && vnode->ref_list.referring.length ())
> {
> enum tls_model new_model = decl_default_tls_model (decl);
> - gcc_checking_assert (new_model >= decl_tls_model (decl));
> - set_decl_tls_model (decl, new_model);
> + STATIC_ASSERT (TLS_MODEL_GLOBAL_DYNAMIC <
> TLS_MODEL_LOCAL_DYNAMIC);
> + STATIC_ASSERT (TLS_MODEL_INITIAL_EXEC < TLS_MODEL_LOCAL_EXEC);
> + /* We'd prefer to assert that recomputed model is not weaker than
> + what the front-end assigned, but cannot: see PR 107353. */
> + if (new_model >= decl_tls_model (decl))
> + set_decl_tls_model (decl, new_model);
> }
> }
> }
> --
> 2.37.2
