Re: automake issue

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Oct 21 15:33, Ken Brown wrote:
> On 10/21/2021 9:08 AM, Jon Turney wrote:
> > On 21/10/2021 11:48, Corinna Vinschen wrote:
> > > On Oct 20 16:58, Ken Brown wrote:
> > > > I was debugging with what I thought was an unoptimized build of cygwin1.dll
> > > > (with -O0 in CXXFLAGS), but then I discovered that malloc.cc was actually
> > > > compiled with -O3.  This is because of the following snippet from
> > > > winsup/cygwin/Makefile.am:
> > > > [...]
> > I couldn't find any history which suggests these flags are here due to
> > evidence ('using -O3 makes this benchmark faster'), rather than
> > guesswork ('these files probably contain hotspots, so use -O3 to make it
> > go faster!').
> 
> It's too bad we don't know why this was done.

Optimization.  Either 9 or 16 years ago.  Using very different GCC
versions and *only* on 32 bit at the time.  It's pretty unlikely they
are still needed, especially on 64 bit.  If it works fine without them,
we should just remove them.

> In the meantime, I'll work
> around the problem by using a private branch in which that block is removed.
> I tried Corinna's suggestion of setting CFLAGS=-g, but that didn't produce
> an unoptimized build.  I still saw '-O2 -g' when building newlib and '-O2 -g
> -g -O2' when building cygwin.

Yeah, I configure the entire tree with C{XX}FLAGS=-g from scratch for
en entirely unoptimized tree, because I want newlib usually unoptimized
as well.


Corinna