[Bug bootstrap/84402] [meta] GCC build system: parallelism bottleneck

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84402

--- Comment #21 from rguenther at suse dot de <rguenther at suse dot de> ---
On Wed, 4 Apr 2018, marxin at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84402
> 
> --- Comment #20 from Martin Liška <marxin at gcc dot gnu.org> ---
> For the libsanitizer/*/*_interceptors I make a quick patch:
> https://github.com/marxin/gcc/commit/5ce658230db567474997fa411f23ac78366487ce
> which basically splits asan_interceptors.cc and
> sanitizer_common_interceptors.inc and moves implementation of string functions
> to a separate compile unit.
> This shrinks time from 38->34s for asan_interceptors.cc being built with
> enabled checking stage1 compiler.
> 
> I believe splitting the interceptors to couple of logical sub-files will make
> it very fast. List of interceptors grepped from
> sanitizer_common_interceptors.inc:
> I can imagine splitting that to components like string, stdio, time, process,
> thread, math,..

The question is of course _why_ it is this slow.  It's not that this
is 10000s of functions or very large ones...