LTO streaming of TARGET_OPTIMIZE_NODE

[Jan Hubicka]

> > 
> > Incrementally I would like to handle optimizations nodes same way and change
> > streaming format to be a set of assignments field_name=value.
> > This way we could behave sanely when some field is introduced or removed by
> > either defaulting it or ignoring it.
> 
> I'm not sure that idea is good ;)  Adding a version / checksum to
> detect a mismatch early would be nice though.  Maybe just compute
> a hash for the fields in the AWK script?

OK, lets see how to handle it incrementaly.
> 
> > Bootstrapped/regtested x86_64-linux, seems sane?
> 
> Sounds sane - I'd like to have a AWK capable person have a look
> for non-portable stuff (did you check AIX? ;))

Good idea, will do today :)
Basically all the AWK is cut&paste from the way save loop is generated, no
really new constructs in it.
> > +  if (CODE_CONTAINS_STRUCT (code, TS_TARGET_OPTION))
> > +    cl_target_option_stream_in (ib, data_in, TREE_TARGET_OPTION (expr));
> > +
> >    if (code == OMP_CLAUSE)
> >      lto_input_ts_omp_clause_tree_pointers (ib, data_in, expr);
> 
> Any reason you don't use bitpacks and stream it from 
> [un]pack_value_fields?  We can happily pack strings there as well.
> The 'body' streaming is for tree pointers only.

Hmm, I did not notice we have pack_string.  Will go with bitpacks then.
> > @@ -963,6 +960,9 @@ streamer_write_tree_body (struct output_
> >    if (CODE_CONTAINS_STRUCT (code, TS_CONSTRUCTOR))
> >      write_ts_constructor_tree_pointers (ob, expr, ref_p);
> >  
> > +  if (CODE_CONTAINS_STRUCT (code, TS_TARGET_OPTION))
> > +    cl_target_option_stream_out (ob, TREE_TARGET_OPTION (expr));
> > +
> >    if (code == OMP_CLAUSE)
> >      write_ts_omp_clause_tree_pointers (ob, expr, ref_p);
> >  }
> 
> Otherwise looks good.

OK, I will update the changes above and test AIX today.
Incrementally I will send patch to disable the TARGET_OPTION_NODE regeeneration from attribute
and to stream TARGET_OPTION_NODE for all functions (this is tested on firefox and AIX by now
and works).

For optimization node I think I can follow exactly the same strategy (to avoid writting binary blobs
that are not portable). I plan to add Ipa and Late modifiers to the format to annotate flags that
affects only Ipa or Late codegen/optimization (ltrans).  This way we can add comparers for inliner
ignoring the flags that are not marked Late and streamer that streams only Ipa/Late.

If this plan sounds sane, I can do it today I believe.

Across stage3 early stage3 I can update IPA passes to not check global flags during LTO so
we can support correctly support different LTO flags (like -fno-inline) in the optimization
nodes...

Honza
> 
> Thanks,
> Richard.