Bug#531348: Please compile xulrunner with PGO optimizations

[Mike Hommey]

On Mon, Jun 01, 2009 at 11:49:10PM -0400, Craig Andrews wrote:
> > There are a whole lot of problems that make it almost impossible:
> > - Build time and buildd resources
> Granted - but Debian builds a lot of packages that require a lot of
> processing power. I can't imagine building xulrunner 2x will be that
> fatal.
> > - Upstream support (PGO is not supported yet on linux)
> https://bugzilla.mozilla.org/show_bug.cgi?id=418866 somewhat true... but
> there are cases of successful building with PGO.
> https://bugs.launchpad.net/ubuntu/+source/xulrunner-1.9/+bug/213708/comments/1
> links to an arch package that does.

FWIW, it doesn't work with what we have in debian. Maybe with gcc-4.5,
but definitely not with gcc-4.4. All I get from the first build pass
(the one with instrumentation) is a crash in strlen at startup:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff40807c1 in strlen () from /lib/libc.so.6
(gdb) bt
#0  0x00007ffff40807c1 in strlen () from /lib/libc.so.6
#1  0x00007ffff6823a92 in __gcov_init () from /tmp/xulrunner/dist/bin/libxul.so
#2  0x00007ffff6824f56 in __do_global_ctors_aux () from /tmp/xulrunner/dist/bin/libxul.so
#3  0x00007ffff51888ab in _init () from /tmp/xulrunner/dist/bin/libxul.so
#4  0x00007fffffffe908 in ?? ()
#5  0x00007ffff7dee429 in ?? () from /lib64/ld-linux-x86-64.so.2
#6  0x00007ffff7dee5af in ?? () from /lib64/ld-linux-x86-64.so.2
#7  0x00007ffff7de1b2a in ?? () from /lib64/ld-linux-x86-64.so.2
#8  0x0000000000000001 in ?? ()
#9  0x00007fffffffeb8c in ?? ()
#10 0x0000000000000000 in ?? ()

I tried several values of optimization flags (default -Os
-freorder-blocks -fno-reorder-functions , -Os and -O2), nothing changes.

Mike