> On 10/23/19 10:02 PM, Jan Hubicka wrote:
> >> Hi,
> >> this patch orders symbols where we copy sections to match the order
> >> of files in the command line. This optimizes streaming process since we
> >> are not opening and closing files randomly and also we read them more
> >> sequentially. This saves some kernel time though I think more can be
> >> done if we avoid doing pair of mmap/unmap for every file section we
> >> read.
> >>
> >> We also read files in random order in ipa-cp and during devirt.
> >> I guess also summary streaming can be refactored to stream all summaries
> >> for a given file instead of reading one sumarry from all files.
> >>
> >> Bootstrapped/regtested x86_64-linux, plan to commit it this afternoon if
> >> there are no complains.
> >>
> >> Honza
> >>
> >> * lto-common.c (lto_file_finalize): Add order attribute.
> >> (lto_create_files_from_ids): Pass order.
> >> (lto_file_read): UPdate call of lto_create_files_from_ids.
> >> * lto-streamer-out.c (output_constructor): Push CTORS_OUT timevar.
> >> (cmp_symbol_files): New.
> >> (lto_output): Copy sections in file order.
> >> * lto-streamer.h (lto_file_decl_data): Add field order.
> > Hi,
> > I have commited the patch but messed up testing so it broke builds with
> > static libraries and checking enabled. This is fixes by this patch
> >
> > * lto-streamer-out.c (cmp_symbol_files): Watch for overflow.
> > Index: lto-streamer-out.c
> > ===================================================================
> > --- lto-streamer-out.c (revision 277346)
> > +++ lto-streamer-out.c (working copy)
> > @@ -2447,7 +2447,12 @@ cmp_symbol_files (const void *pn1, const
> >
> > /* Order within static library. */
> > if (n1->lto_file_data && n1->lto_file_data->id != n2->lto_file_data->id)
> > - return n1->lto_file_data->id - n2->lto_file_data->id;
> > + {
> > + if (n1->lto_file_data->id > n2->lto_file_data->id)
> > + return 1;
> > + if (n1->lto_file_data->id < n2->lto_file_data->id)
> > + return -1;
> > + }
>
> Hi.
>
> It's unclear to me why you need the patch. Isn't that equivalent?
> Why you need only 1 and -1 return values?
ids are 64it unsigned values and the subtraction was running into
overflows. (to be honest i am not sure why they are done this way,
but they come from linker)
Honza
>
> Martin
>
> >
> > /* And finaly order by the definition order. */
> > return n1->order - n2->order;
> >
>
