Re: proposal: substitute-path handles foreign dir separators

Raphael Zulliger
2010-12-20T07:41:06Z

On 17.12.2010 18:50, Pedro Alves wrote:
>
> Here's a patch I wrote a few months back when I was working on
> the "set/show target-file-system-kind" support, but put it on
> the back burner and never looked at it again. It adds a new
> "set source-filenames-matching-scheme dos/unix" command to select
> the behavior at run-time, and adds a new source_filename_cmp function
> to be used whenever we are comparing source file names instead of
> using FILENAME_CMP. I never did an exaustive check on all FILENAME_CMP
> calls that should be replaced, and neither did much testing on it
> when I wrote it. I've new comfirmed it still builds, but didn't retest
> more than that.
>
I applied your patch and tested it against my use case. First of all I
need to admit that I really don't have the "overall picture about GDB
internals" yet. I mention this because I can't judge most parts of your
patch (psymtab.c, buildsym.c, etc.). Opposed to that, I think I do
understand the changes you've done in source.c, filenames.h and
filename_cmp.c.

First of all, your patch doesn't help for my use case. I guess (although
I didn't verify that) your patch only handles "relative" source file
names. Unfortunately, in my case, find_and_open_source is called with
the following argument values:

filename:
"X:\\projects\\inos_projects\\inos_trunk\\os\\inos\\src\\inos.cpp"
dirname:
"/cygdrive/x/projects/inos_projects/inos_trunk/testing/hwtarget_603/"
*fullpath: 0

I use the following substitute-path rule:
set substitute-path X:\\projects\\inos_projects
/mnt/hgfs/projects/inos_projects/

According to my understanding, if having absolute file names in the
binary, the following if statement (in find_and_open_source) should
become true:
if (IS_ABSOLUTE_PATH (filename))
which, unfortunately, is not the case because IS_ABSOLUTE_PATH
internally uses Unix style file name rules.

To make a long story short: I think that we still need to do the things
that are done by my original patch to make my use case working:
. Create some kind of IS_ABSOLUTE_PATH which (optionally) works for
all file name styles
. Create some kind fo IS_DIR_SEPARATOR which (optionally) works for
all file name styles
. Make sure we don't pass DOSish file names to openp (the one in
find_and_open_source) if running on a Unix-like system

Assuming that my statements/observations are right, how would be
implement these points?
We could do similar things with IS_ABSOLUTE_PATH and IS_DIR_SEPARATOR as
has been done with the FILENAME_CMP macro by your patch. Having done
this, we probably need a third options for
source-filenames-matching-scheme: 'mixed'. As I mentioned in the
original post, it may happen that you end up with a binary which has
been linked from libraries that were compiled on different platforms
(e.g. by different developer teams). As far as I understand GDB's source
code handling, this would require that IS_ABSOLUTE_PATH and
IS_DIR_SEPARATOR need to test for both file name styles.

Thanks.
Raphael