On 02/04/2017 10:58 AM, Ken Moffat wrote:
On Sat, Feb 04, 2017 at 12:07:55AM -0600, DJ Lucas wrote:
Interesting, I had just suggested to Bruce (the other day on IRC) that we go
ahead and do it. I've seen absolutely no failures with bfd as the default
linker with both big DEs installed. I haven't gotten around to newer QT yet. I
was hoping we'd see a 2.28 release well before now. Does QT pick up gold by
default?
It seems not - I have both ld.gold, ld.bfd and ldd (bfd) in /usr/bin,
with a /usr/bin/gold directory containing an ld symlink. I normally
put that first on the PATH, but using a normal PATH it used ld.bfd.
I'm still of the mind to provide everything that the package can provide
with two caveats. 1. We aren't increasing dependencies drastically. 2.
No harm comes from the change. This even at the expense of a couple of
SBU -- 0.1 for bison in Ch5 and ~3 for the gold test suite IIRC -- and
regardless of any perceived benefit. I might be in the minority here, so
opinions are welcome (not sure if Ken's are fully expressed above).
On the flip, nothing prevents us from burring the two additional
switches in the wiki if there are strong feelings the other way. While I
think a *drastic* speed/size benefit has been sufficiently debunked
(even if only with anecdotal evidence), that doesn't render it useless.
Samba was a good example where the maintainers were tracking down issues
in their code that bfd managed to gloss over.
As to usability, in the default configuration, you can use -fuse-gold to
CFLAGS/CXXFLAGS if you want to use it explicitly, but otherwise, as far
as I have been able to tell, it is ignored unless the package maintainer
explicitly checks for it (and presumably, the maintainer knows whether
their dependent libraries are correct or if they still depend on bfd's
DL-like workarounds).
With 2.27, however, the test suite is, um...messy, with a completely
different testing framework. 2.28 will hopefully be out the door before
package freeze, but I'd like to wait and see what things look like at
its release.
Some interesting linker optimizations coming down the pipe as well, this
one https://sourceware.org/ml/binutils/2017-02/msg00032.html for
instance has piqued my interest. That is a 3.97% reduction in size. Now
granted, that's a really big executable, and not anywhere near typical.
--DJ
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