On 2019-12-19 11:06 +0100, Jan Hubicka wrote:
> This is variant of your patch I comitted. It also adds verification so
> we get ICE rather then wrong code. In addition I moved the checks away
> rom used_from_object_file. This function is about non-LTO objects
> linked into the DSO and thus does not really fit for the check.
> Lastly we can not rely on symver attribute to still be present here.
>
> Regtested x86_64-linux and comitted.
> Honza
> * cgraph.c (cgraph_node_cannot_be_local_p_1): Prevent targets of
> symver attributes to be localized.
> * ipa-visibility.c (cgraph_externally_visible_p,
> varpool_node::externally_visible_p): Likewise.
> * symtab.c (symtab_node::verify_base): Check visibility of symbol
> versions.
>
> * lto-common.c (read_cgraph_and_symbols): Work around binutils
> PR25424
/* snip */
> Index: ipa-visibility.c
> ===================================================================
> --- ipa-visibility.c (revision 279523)
> +++ ipa-visibility.c (working copy)
> @@ -220,6 +220,14 @@ cgraph_externally_visible_p (struct cgra
> && lookup_attribute ("dllexport",
> DECL_ATTRIBUTES (node->decl)))
> return true;
> +
> + /* Limitation of gas requires us to output targets of symver aliases as
> + global symbols. This is binutils PR 25295. */
> + ipa_ref *ref;
> + FOR_EACH_ALIAS (node, ref)
> + if (ref->referring->symver)
> + return true;
> +
> if (node->resolution == LDPR_PREVAILING_DEF_IRONLY)
> return false;
> /* When doing LTO or whole program, we can bring COMDAT functoins static.
> @@ -284,14 +292,13 @@ varpool_node::externally_visible_p (void
> DECL_ATTRIBUTES (decl)))
> return true;
>
> - /* See if we have linker information about symbol not being used or
> - if we need to make guess based on the declaration.
> + /* Limitation of gas requires us to output targets of symver aliases as
> + global symbols. This is binutils PR 25295. */
> + ipa_ref *ref;
> + FOR_EACH_ALIAS (this, ref)
> + if (ref->referring->symver)
> + return true;
>
> - Even if the linker clams the symbol is unused, never bring internal
> - symbols that are declared by user as used or externally visible.
> - This is needed for i.e. references from asm statements. */
> - if (used_from_object_file_p ())
> - return true;
Are these two lines removed intentionally?
> if (resolution == LDPR_PREVAILING_DEF_IRONLY)
> return false;
>
> Index: lto/lto-common.c
> ===================================================================
--
Xi Ruoyao <xry...@mengyan1223.wang>
School of Aerospace Science and Technology, Xidian University
