Re: HPPA constructor merge patch, PR middle-end/45388

[Jan Hubicka <hubicka at ucw dot cz>]

> On 09/28/2010 08:36 AM, Jan Hubicka wrote:
> > This is bit difficult to arrange with LTO.  We produce at compile time the consturctor
> > function with magic names, then at LTO time we want to produce single constructor function
> > calling them all.   We would need to guess on what name is the magic name (by same logic
> > as what collect does) and rename function back.
> > I can definitly implement it, but it seems more hackish than the collect2 side change.
> 
> An alternative is that at compile time we emit
> 
>   _Z41__static_initialization_and_destruction_0ii
> 
> to the intermediate code as the constructor, and
> 
>   GLOBAL__I__ZN2c12f6Ev calls
> 
> to the object code calling _Z41.  However, we don't emit
> GLOBAL to the intermediate code at all.  Thus when LTO 
> replaces the object files there's no trace of the original
> GLOBAL function at all, and thus collect2 does not see it.
> LTO will simply see _Z41 and call that function directly.
> 
> This is not entirely different from the case in which we
> have .ctor support -- it's not like we read in the piece
> of the object code that contains the .ctor data.  Just
> consider the GLOBAL function object file data.
> 
> This should be doable with a flag on the decl for GLOBAL
> that indicates that it should not be serialized.

Or we can just produce those collected global constructors after
serialization.  I will check...

Honza
> 
> 
> r~