cygport may not create debug info if top directory contains a symlink
Christian Franke
Christian.Franke@t-online.de
Wed Sep 20 10:58:07 GMT 2023
Brian Inglis wrote:
> On 2023-09-18 04:41, Christian Franke via Cygwin-apps wrote:
>> Brian Inglis wrote:
>>> On 2023-09-17 08:01, Jon Turney via Cygwin-apps wrote:
>>>> On 16/09/2023 15:17, Christian Franke via Cygwin wrote:
>>>>> Found during tests of busybox package:
>>>>> If the path of the top build directory contains a symlink and the
>>>>> project's build scripts normalize pathnames, no debug info is
>>>>> created by cygport.
>>>>>
>>>>> This is because options like
>>>>> -fdebug-prefix-map=${B}=/usr/src/debug/${PF}
>>>>> have no effect because ${B} contains a symlink but the compiler is
>>>>> run with the real source path.
>>>>
>>>> I think that there was some historical bug with gcc where a
>>>> relative path for the old path in this mapping wasn't correctly
>>>> handled, which is why were using an absolute path here at all.
>>>>
>>>> So changing it to something like [1] (if that works), might be better.
>>>>
>>>> [1]
>>>> https://github.com/jon-turney/cygport/commit/4175d456a9184c5cdebd8bfb4b5ba30583cedd66
>
> Should bin/cygport.in:534: not have $B between the == as in line 531:
>
> declare ${flags}+=" -fdebug-prefix-map=${B}=/usr/src/debug/${PF}"
> ...
> declare ${flags}+=" -fdebug-prefix-map==/usr/src/debug/${PF}"
>
> or be hoist above the condition if identical, unless that is some
> undocumented default for cwd?
I guess the == without ${B} is intentional because it makes the debug
source path relative to ${B} as lines 535-536 also do.
> ...
>>> An STC script which creates test dirs to demonstrate the issue and
>>> show the alternative outputs would be nice so anyone can see.
>
>> $ ln -s /usr/src /tmp/source
>>
>> $ cd /tmp/source
>>
>> $ pwd
>> /tmp/source
>>
>> $ /bin/pwd
>> /usr/src
>>
>> $ pwd -P
>> /usr/src
>>
>> $ /bin/pwd -L
>> /tmp/source
>
> Thanks, looks good - care to submit a patch, including above
> suggestions, to cover all bases?
>
Users may have a good reason to use a symlinked directory, e.g. fake the
original build path during a rebuild. So I'm still not sure how to
handle this.
- Simply warn the user:
declare -r top=$(cd ${_topdir}; pwd);
+if [ "${top}" != "$(cd ${_topdir}; pwd -P)" ]
+then
+ warning "symlinks in ${top} do not work with some build systems."
+fi
unset _topdir;
- or enforce the real path:
-declare -r top=$(cd ${_topdir}; pwd);
+declare -r top=$(cd ${_topdir}; pwd -P);
+if [ "${top}" != "$(cd ${_topdir}; pwd -L)" ]
+then
+ inform "using real path ${top} as top level directory."
+fi
unset _topdir;
Projects using GNU autotools and cyg{conf,make,install} in cygport are
usually not affected by symlinks in ${top}.
--
Regards,
Christian
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