Re: Do not stream types in DECL_CONTEXT

[Richard Biener <rguenther at suse dot de>]

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 = &TREE_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 <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)