Re: [PATCH] Don't munge yacc's #line directives

[Patrick Palka <patrick at parcs dot ath dot cx>]

On Thu, Jan 8, 2015 at 7:24 AM, Patrick Palka <patrick@parcs.ath.cx> wrote:
> On Thu, Jan 8, 2015 at 7:02 AM, Pedro Alves <palves@redhat.com> wrote:
>> On 01/08/2015 01:01 AM, Patrick Palka wrote:
>>> The #line directives within GDB's autogenerated yacc files (e.g.
>>> c-exp.c) are being munged by a dubious sed expression that is causing
>>> these directives to refer to nonexistent source files.  As a result it
>>> is currently not possible to debug these source files at source level.
>>>
>>> The culprit sed expression was added by commit 954d8cae for non-obvious
>>> reasons.
>>
>> That predates when we started putting more complete descriptions
>> in the commit log.  Did you look for the mailing list patch submission?
>> That should have included a description.  If not, then maybe Jan
>> recalls.  The expression refers to basename and slashes, it makes
>> me wonder whether this was build-in-srcdir vs build-out-of-srcdir
>> related.
>
> Here is the corresponding ML listing:
> https://sourceware.org/ml/gdb-patches/2010-11/msg00265.html
> So it seems that ylwrap once used relative paths when referring to the
> source yacc file instead of absolute paths, and the sed expression was
> there to fix that.  But our copy of ylwrap doesn't seem to have this
> problem anymore.
>
>>
>>
>>> My guess is that the expression was added to work around a bug
>>> in ylwrap which has since been fixed upstream: if I revert the November
>>> 2014 update to ylwrap, commit be3046511, then the culprit sed line no
>>
>> OOC, got url for that git repo?
>
> Oops, I truncated the commit hash too much.  The commit in question is
> e30465112 from within the binutils-gdb repo.  The commit synced some
> files with upstream automake whose git repo is
> http://git.savannah.gnu.org/cgit/automake.git.

Here is the upstream automake patch that is probably responsible for
making the sed expression in question obsolete:
http://git.savannah.gnu.org/cgit/automake.git/commit/lib/ylwrap?id=b6359a5f310160c8a4a2e8e8c0105408412ce400

>
>>
>> Thanks,
>> Pedro Alves
>>
>>> longer causes the above mentioned issue.
>>>
>>> So this patch removes the culprit sed script since it does not seem
>>> needed anymore; the emitted #line directives look and work fine without
>>> it.
>>>
>>> gdb/ChangeLog:
>>>
>>> 2015-01-07  Patrick Palka  <patrick@parcs.ath.cx>
>>>
>>>       * Makefile.in (.y.c): Don't munge yacc's #line
>>>       directives.
>>> ---
>>>  gdb/Makefile.in | 1 -
>>>  1 file changed, 1 deletion(-)
>>>
>>> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
>>> index 31c8a4c..97d0045 100644
>>> --- a/gdb/Makefile.in
>>> +++ b/gdb/Makefile.in
>>> @@ -1856,7 +1856,6 @@ po/$(PACKAGE).pot: force
>>>            -e 's/\([ \t;,(]\)free\([ \t]*[&(),]\)/\1xfree\2/g' \
>>>            -e 's/\([ \t;,(]\)free$$/\1xfree/g' \
>>>            -e '/^#line.*y.tab.c/d' \
>>> -          -e "s/^\(#line.*\)`basename $<`/\1`echo $<|sed 's/\//\\\\\//g'`/" \
>>>         < $@.tmp > $@
>>>       rm -f $@.tmp
>>>  .l.c:
>>>
>>
>>