On Mon, Jul 15, 2013 at 11:18 AM, Jan Hubicka <hubi...@ucw.cz> wrote: >> On Mon, Jul 15, 2013 at 11:05 AM, Jan Hubicka <hubi...@ucw.cz> wrote: >> >> > The next thing is how to tell GNU LD/Gold the relative order of functions. >> > I.e. my_function_section.order.125 or something like that? >> >> Gold has a --section-ordering-file option that lets you specify the >> order in which sections should appear in the executable. Sections not >> listed there follow the default rules. > > Yep, the problem is where to produce the section ordering file. > The scheme is as follows: > - with -fprofile-generate instrument every function entry point and record > time of first and last invocation of the functoin > - At compile time we take functions that are executed during the startup > and we want to order them in the increasing order of the first invocation > time measured at FDO time. So we know the relative position of given > function > in the program, but not the complette function order.
Perhaps I misunderstand, but you can use --section-ordering-file without knowing the complete function ordering. Just specify the functions you care about. Ian
