On Thu, Nov 01, 2012 at 11:11:13AM -0700, Xinliang David Li wrote:
> But it skips those globals without static storage and marked as not
> addressable.
>
> It seems to me you want to skip all stack local variables that are not
> address escaped. Without address escape analysis, the address taken
> bit (not the same as addressable attribute) should be used. As far as
> I can tell, such bit is not available in var_decl. The varpool_node
> has one, but it is only for var_decls with static storage. It is also
> unfortunate that there is no single bit to test if a variable is
> function auto, though there is an interface to call which is
> 'auto_var_in_fn_p (...)'. The condition to skip such variable
> references are:
>
> if (tcode == VAR_DECL && auto_var_in_fn_p (expr, ..) &&
> !address_taken (expr))
>
> The TREE_ADDRESSABLE check seems redundant -- if the var_decl (instead
> of ssa name) appears in the assignment, why would it not be
> 'addressable'? And being addressable does not mean it is address taken
> either.
TREE_ADDRESSABLE really is a flag whether the
address of the decl is ever taken (or addresses of its fields etc.),
and it is updated from time to time (execute_update_addresses_taken)
after certain passes. Don't understand why you think it is redundant.
Jakub
