Re: GDB now takes 4 minutes to start up with remote gdbserver target

[Gary Benson <gbenson at redhat dot com>]

Sandra Loosemore wrote:
> On 07/24/2015 10:05 AM, Pedro Alves wrote:
> > On 07/24/2015 04:27 PM, Paul_Koning@Dell.com wrote:
> > > But having sysroot default to target is also a bad idea for lots
> > > of other people.  Consider embedded systems: you presumably have
> > > stripped images there, but unstripped ones on your build host.
> > 
> > But in that scenario, with the old default sysroot, how was gdb
> > finding the binaries on the build host?  The binaries on the
> > equilalent locations on the host's root will certainly not match
> > the embedded/target system's.  In that scenario, you must have
> > been pointing the "set sysroot" somewhere local?  And if you do
> > that, nothing changes in 7.10, gdb will still access the files on
> > the local filesystem.
> > 
> > From the discussion so far, it seems that the only case that ends
> > up regressing is the case where the host and target share both the
> > filesystem, and the host/target paths match.  I don't know off
> > hand how to make gdb aware of that automatically.
> 
> There's also the case where the host and target sysroot locations do
> not match at all.  As I said, this used to work reasonably well for
> application debugging, where the user isn't interested in debugging
> shared libraries and doesn't care if the shared library symbol
> information isn't available to GDB.  It used to print a helpful
> message suggesting using "set sysroot" if the user wants the shared
> library information, instead of hanging on startup with no
> indication of what the trouble is or how to fix it.  I can't see the
> new default behavior as an improvement over the old.
> 
> > That seems like enough of a special case that could well be
> > handled by an explicit "set sysroot /" in e.g., the toolchain's
> > system-gdbinit, or by building gdb with "--with-sysroot=/".
> 
> There are a bunch of possible workarounds for this, but why can't we
> make GDB "just work" by default, as it used to, instead of requiring
> users to build GDB differently or install a workaround or issue
> extra commands manually that they didn't used to need at all?

I have an idea for a solution to this.  I should know in a few hours
if it can work.  Tomorrow morning at the very latest.

Thanks,
Gary

-- 
http://gbenson.net/