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Re: Group static constructors and destructors in specific subsections

> On Mon, Jul 15, 2013 at 11:18 AM, Jan Hubicka <> wrote:
> >> On Mon, Jul 15, 2013 at 11:05 AM, Jan Hubicka <> 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.

The thing is that when compiling given object file, you know only functions in
that object file, so you can not produce full --section-ordering-file.  We
would need a tool colleting the partial orders from all objects to single file
that I think may be just done in linker.

> Ian

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