Re: [PATCH] kbuild: specify absolute paths for cscope

Re: [PATCH] kbuild: specify absolute paths for cscope

[Michal Marek]

On 26.11.2009 13:34, Daniel Vetter wrote:
> Some tools (like my favourite editor, vim) can't handle relative
> paths from cscope as soon as cscope.out is no longer in $PWD. Use
> absolute paths when generating cscope.files, which seems to be
> the recommended way to generate cscope.out, anyway (at least according
> to cscope.sf.net).

But it will fail if you rename the source directory. I'm not sure what
is worse, I myself don't use cscope much. Fixing vim would be the ideal
solution of course (it already handles ../tags fine).

Michal

Re: [PATCH] kbuild: specify absolute paths for cscope

[Sam Ravnborg]

On Mon, Nov 30, 2009 at 06:13:47PM +0100, Michal Marek wrote:
> On 26.11.2009 13:34, Daniel Vetter wrote:
> > Some tools (like my favourite editor, vim) can't handle relative
> > paths from cscope as soon as cscope.out is no longer in $PWD. Use
> > absolute paths when generating cscope.files, which seems to be
> > the recommended way to generate cscope.out, anyway (at least according
> > to cscope.sf.net).
> 
> But it will fail if you rename the source directory. I'm not sure what
> is worse, I myself don't use cscope much. Fixing vim would be the ideal
> solution of course (it already handles ../tags fine).

For tags I recall we fall back to absolute path only for O=... builds.
This made the tags file considerably smaller for a non O=.. build
thus speeding up the search.

So unconditionally using absolute paths for cscope may have drawbacks.

	Sam

Re: [PATCH] kbuild: specify absolute paths for cscope

[Daniel Vetter]

On Mon, Nov 30, 2009 at 07:11:09PM +0100, Sam Ravnborg wrote:
> On Mon, Nov 30, 2009 at 06:13:47PM +0100, Michal Marek wrote:
> > On 26.11.2009 13:34, Daniel Vetter wrote:
> > > Some tools (like my favourite editor, vim) can't handle relative
> > > paths from cscope as soon as cscope.out is no longer in $PWD. Use
> > > absolute paths when generating cscope.files, which seems to be
> > > the recommended way to generate cscope.out, anyway (at least according
> > > to cscope.sf.net).
> > 
> > But it will fail if you rename the source directory. I'm not sure what
> > is worse, I myself don't use cscope much. Fixing vim would be the ideal
> > solution of course (it already handles ../tags fine).
> 
> For tags I recall we fall back to absolute path only for O=... builds.
> This made the tags file considerably smaller for a non O=.. build
> thus speeding up the search.
> 
> So unconditionally using absolute paths for cscope may have drawbacks.

I've just tried to use cscope with a working directory not equal to the
directory where cscope.out resides:

$ cscope -d -f src/cscope.out

It can't handle relative paths. When I try to open a file (via a
reference) from within cscope, it calls up vim with the wrong path.  So I
think this is a fundamental cscope bug (and not a vim problem).  As I've
already said, every tutorial on the web I could find uses absolute paths,
too, so the problem seems to be common, as is the work-around.  Therefore
please apply this patch (perhaps changing my comment to "cscope is broken
with relative paths, work around it via absolute paths").

Thanks, Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [PATCH] kbuild: specify absolute paths for cscope

[Michal Marek]

On 1.12.2009 10:42, Daniel Vetter wrote:
> I've just tried to use cscope with a working directory not equal to the
> directory where cscope.out resides:
> 
> $ cscope -d -f src/cscope.out
> 
> It can't handle relative paths. When I try to open a file (via a
> reference) from within cscope, it calls up vim with the wrong path.  So I
> think this is a fundamental cscope bug (and not a vim problem).  As I've
> already said, every tutorial on the web I could find uses absolute paths,
> too, so the problem seems to be common, as is the work-around.  Therefore
> please apply this patch (perhaps changing my comment to "cscope is broken
> with relative paths, work around it via absolute paths").

OK, you convinced me. I applied it to for-next, with a minor edit to fix
O= builds (the tree variable is an absolute path already):
http://repo.or.cz/w/linux-kbuild.git/commitdiff/037aaae02ecf3925b843316868743c755d73fb22
I hope the next guy won't come and complain the he moved linux-2.6.xy to
linux-2.6.xy.orig and cscope stopped working :).


On 30.11.2009 19:11, Sam Ravnborg wrote:
> For tags I recall we fall back to absolute path only for O=... builds.
> This made the tags file considerably smaller for a non O=.. build
> thus speeding up the search.
> 
> So unconditionally using absolute paths for cscope may have drawbacks.

I tried it and this part seems OK. Generating the database took more or
less the same time, cscope.out grew by less than 1% and opening cscope
and running a query for 'printk' slowed down by about 8%, I think that's
bearable.

Michal