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

[Sandra Loosemore <sandra at codesourcery dot com>]

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?

-Sandra