Cgraph alias reorg 15/14 (New infrastructure for same body aliases)

H.J. Lu hjl.tools@gmail.com
Sun Jun 12 15:45:00 GMT 2011


On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>>
>> This also pretty much destroyed C++ for ia32:
>>
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378
>> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html
>
> Hi,
> It seems somewhat amazing that we hit kernel sensitive miscompilation here.
> The problem most probably is the fact that thunks and functions with thunks can become
> local. This is correct since thunks are represented as direct calls now, but this
> makes i386 to use local ABI when calling or compiling them.
>
> Does the following patch help? We may also need to look for the presence of thunk
> callers.
>
> Index: ipa.c
> ===================================================================
> --- ipa.c       (revision 174958)
> +++ ipa.c       (working copy)
> @@ -120,6 +120,7 @@ static bool
>  cgraph_non_local_node_p_1 (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
>  {
>    return !(cgraph_only_called_directly_or_aliased_p (node)
> +           && !ipa_ref_has_aliases_p (&node->ref_list)
>            && node->analyzed
>            && !DECL_EXTERNAL (node->decl)
>            && !node->local.externally_visible
> @@ -132,7 +133,11 @@ cgraph_non_local_node_p_1 (struct cgraph
>  static bool
>  cgraph_local_node_p (struct cgraph_node *node)
>  {
> -   return !cgraph_for_node_and_aliases (cgraph_function_or_thunk_node (node, NULL),
> +   struct cgraph_node *n = cgraph_function_or_thunk_node (node, NULL);
> +
> +   if (n->thunk.thunk_p)
> +     return false;
> +   return !cgraph_for_node_and_aliases (n,
>                                        cgraph_non_local_node_p_1, NULL, true);
>
>  }
>

I am testing it now.  Will know the results in 2 hours.

Thanks.

-- 
H.J.



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