Re: lto gimple types and debug info

["Richard Guenther" <richard dot guenther at gmail dot com>]

On Fri, Jul 25, 2008 at 1:47 PM, Kenneth Zadeck
<zadeck@naturalbridge.com> wrote:
> Arnaud Charlet wrote:
>>>
>>> When danny and it wrote the ipa-type-escape pass, mark mitchell was all
>>> over us because we assumed that the type system had some semantic meaning.
>>>  We ended up with a pass that generally finds nothing useful.  I would very
>>> much like to redo that pass once we can mark a type as coming from a
>>> language with a real type system.
>>>
>>
>> Did you enable Ada at this time ?
>> What was this pass supposed to do ?
>>
>> Arno
>>
>
> I do not remember. The problem is not dealing with Ada, it is dealing with
> Ada as if it was C.  What we do is correct for ada or java, it is just much
> more conservative that anyone would ever be if one were writing a compiler
> for those languages.
> the pass determines if all uses of a type are completely encapsulated within
> the compilation unit.  Most types are generally not, but if you compile with
> -combine (which only works for C), then in theory there would be more of
> them.
>
> The idea is that if you have a fully encapsulated type, then the compiler
> would be free to implement any variables of this type as it saw fit
> (changing the alignment, reordering the fields, peeling ...).

I actually never understood why we need type escape analysis here.
Can't we just see if the actual objects do escape?

Richard.