Re: [PATCH] ASAN: handle addressable params (PR sanitize/81040).

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Jun 30, 2017 at 11:21:48AM +0200, Martin Liška wrote:
> @@ -858,6 +864,132 @@ sanitize_asan_mark_poison (void)
>      }
>  }
>  
> +/* Rewrite all usages of tree OP which is a PARM_DECL with a VAR_DECL
> +   that is it's DECL_VALUE_EXPR.  */
> +
> +static tree
> +rewrite_usage_of_param (tree *op, int *walk_subtrees, void *)
> +{
> +  if (TREE_CODE (*op) == PARM_DECL && DECL_HAS_VALUE_EXPR_P (*op))
> +    {
> +      *op = DECL_VALUE_EXPR (*op);
> +      *walk_subtrees = 0;
> +    }

If you are going to rely just on DECL_HAS_VALUE_EXPR_P here

> +  for (tree arg = DECL_ARGUMENTS (current_function_decl);
> +       arg; arg = DECL_CHAIN (arg))
> +    {

I think you should gcc_assert here that !DECL_HAS_VALUE_EXPR_P (arg) here.

If that ever fails, another possibility would be to temporarily clear those
flags and remember it and then set it again after the walk_*.  The question
would be what to do with arguments that already have DECL_VALUE_EXPR, are
addressable and you want to rewrite them.

> +      if (TREE_ADDRESSABLE (arg) && !TREE_ADDRESSABLE (TREE_TYPE (arg)))
> +	{
> +	  TREE_ADDRESSABLE (arg) = 0;
> +	  /* The parameter is no longer addressable.  */
> +	  tree type = TREE_TYPE (arg);
> +	  has_any_addressable_param = true;

Otherwise LGTM.

	Jakub