On Mon, 20 Aug 2018, Jan Hubicka wrote:
> Hi,
> this patch drops types from decl context in free lang data. This is not
> possible
> for field decls (because they are chained by TREE_CHAIN), for variably
> modified
> types (becuase it is used in tree_is_indexable and other places) and for
> virtual functions/tables (because it is used by devirt machinery to loop back
> the type).
>
> lto Bootstrapped/regtested x86_64-linux, OK?
OK.
Richard.
> * tree.c (free_lang_data_in_decl): Remove types from DECL_CONTEXT
> when possible.
> Index: tree.c
> ===
> --- tree.c(revision 263586)
> +++ tree.c(working copy)
> @@ -5380,6 +5380,29 @@ free_lang_data_in_decl (tree decl)
> nextp = _CHAIN (var);
> }
> }
> + /* We need to keep field decls associated with their trees. Otherwise tree
> + merging may merge some fileds and keep others disjoint wich in turn will
> + not do well with TREE_CHAIN pointers linking them.
> +
> + Also do not drop containing types for virtual methods and tables because
> + these are needed by devirtualization. */
> + if (TREE_CODE (decl) != FIELD_DECL
> + && ((TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL)
> + || !DECL_VIRTUAL_P (decl)))
> +{
> + tree ctx = DECL_CONTEXT (decl);
> + /* Variably modified types are needed for tree_is_indexable to decide
> + whether the type needs to go to local or global section.
> + This code is semi-broken but for now it is easiest to keep contexts
> + as expected. */
> + if (ctx && TYPE_P (ctx)
> + && !variably_modified_type_p (ctx, NULL_TREE))
> + {
> +while (ctx && TYPE_P (ctx))
> + ctx = TYPE_CONTEXT (ctx);
> +DECL_CONTEXT (decl) = ctx;
> + }
> +}
> }
>
>
>
>
--
Richard Biener
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
