[ragel-users] [PATCH 0/3] Fix Cygwin build

Tue Nov 27 22:03:33 UTC 2018

This seems to confirm my interpretation of "-no-undefined":

$ libtool --help --mode=link | grep -- -no-undefined
   -no-undefined     declare that a library does not refer to external symbols

Ken

On 11/27/2018 11:09 AM, Ken Brown wrote:
> OK, that's good that I can forget about --with-ragel.  As to how -no-undefined
> works, I've done some googling and still don't fully understand it.  I see the
> -no-undefined flag passed to libtool but then it doesn't appear in the final
> link command:
> 
> /bin/sh ../libtool  --tag=CXX   --mode=link g++  -Wall -g -no-undefined...
> 
> libtool: link: g++ -shared -nostdlib
> /usr/lib/gcc/x86_64-pc-cygwin/7.3.0/crtbeginS.o  .libs/libfsm_la-idbase.o
> .libs/libfsm_la-fsmstate.o .libs/libfsm_la-fsmbase.o .libs/libfsm_la-fsmattach.o
> .libs/libfsm_la-fsmmin.o .libs/libfsm_la-fsmgraph.o .libs/libfsm_la-fsmap.o
> .libs/libfsm_la-fsmcond.o .libs/libfsm_la-fsmnfa.o .libs/libfsm_la-common.o
> .libs/libfsm_la-redfsm.o .libs/libfsm_la-gendata.o .libs/libfsm_la-allocgen.o
> .libs/libfsm_la-codegen.o .libs/libfsm_la-actexp.o .libs/libfsm_la-binvar.o
> .libs/libfsm_la-tables.o .libs/libfsm_la-tabgoto.o .libs/libfsm_la-tabvar.o
> .libs/libfsm_la-binary.o .libs/libfsm_la-bingoto.o .libs/libfsm_la-actloop.o
> .libs/libfsm_la-flat.o .libs/libfsm_la-flatgoto.o .libs/libfsm_la-flatvar.o
> .libs/libfsm_la-goto.o .libs/libfsm_la-gotoloop.o .libs/libfsm_la-gotoexp.o
> .libs/libfsm_la-ipgoto.o .libs/libfsm_la-dot.o .libs/libfsm_la-asm.o
> -L/home/kbrown/src/colm/src -L/usr/lib/gcc/x86_64-pc-cygwin/7.3.0
> -L/usr/lib/gcc/x86_64-pc-cygwin/7.3.0/../../../../x86_64-pc-cygwin/lib/../lib
> -L/usr/lib/gcc/x86_64-pc-cygwin/7.3.0/../../../../lib -L/lib/../lib
> -L/usr/lib/../lib
> -L/usr/lib/gcc/x86_64-pc-cygwin/7.3.0/../../../../x86_64-pc-cygwin/lib
> -L/usr/lib/gcc/x86_64-pc-cygwin/7.3.0/../../.. -lstdc++ -lgcc_s -lgcc -lcygwin
> -ladvapi32 -lshell32 -luser32 -lkernel32 -lgcc_s -lgcc
> /usr/lib/gcc/x86_64-pc-cygwin/7.3.0/crtend.o  -g   -o .libs/cygfsm-0.dll
> -Wl,--enable-auto-image-base -Xlinker --out-implib -Xlinker .libs/libfsm.dll.a
> 
> I think the point might be that gcc/g++ will give errors on Cygwin if there are
> undefined symbols in shared libraries, and libtool enforces that by insisting on
> the -no-undefined flag, which is simply an assertion that there are no undefined
> symbols.  That's mostly a guess.
> 
> I have the same automake, autoconf, and libtool versions as you, but a newer gcc
> (7.3.0).
> 
> Ken
> 
> On 11/27/2018 5:49 AM, Adrian Thurston wrote:
>> First, the easy part ... you can take out --with-ragel and --with-kelbt options.
>> They were only there to fall back to during the transition to the colm frontend.
>> I've committed to the colm parser though and will be removing the old one soon.
>>
>> With regards to linking, it has no effect for me when I used -no-undefined.
>> Seems to get stripped out by autotools because it doesn't make it into the link
>> command.
>>
>> libragel_la_LDFLAGS = -no-undefined
>>
>> ... results in ...
>>
>> libtool: link: g++  -fPIC -DPIC -shared -nostdlib
>> /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crti.o
>> /usr/lib/gcc/x86_64-linux-gnu/5/crtbeginS.o .libs/libragel_la-parsetree.o
>> .libs/libragel_la-longest.o .libs/libragel_la-parsedata.o
>> .libs/libragel_la-inputdata.o .libs/libragel_la-load.o
>> .libs/libragel_la-reducer.o   -Wl,-rpath
>> -Wl,/home/thurston/devel/ragel/src/.libs -Wl,-rpath
>> -Wl,/home/thurston/pkgs/colm/lib -Wl,-rpath -Wl,/home/thurston/pkgs/ragel/lib
>> -Wl,-rpath -Wl,/home/thurston/pkgs/colm/lib -L/home/thurston/pkgs/colm/lib
>> ./.libs/libfsm.so /home/thurston/pkgs/colm/lib/libcolm.so
>> -L/usr/lib/gcc/x86_64-linux-gnu/5
>> -L/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu
>> -L/usr/lib/gcc/x86_64-linux-gnu/5/../../../../lib -L/lib/x86_64-linux-gnu
>> -L/lib/../lib -L/usr/lib/x86_64-linux-gnu -L/usr/lib/../lib
>> -L/usr/lib/gcc/x86_64-linux-gnu/5/../../.. -lstdc++ -lm -lc -lgcc_s
>> /usr/lib/gcc/x86_64-linux-gnu/5/crtendS.o
>> /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crtn.o  -g -Wl,-soname
>> -Wl,libragel.so.0 -o .libs/libragel.so.0.0.0
>>
>> My setup is ubuntu with the following versions.
>>
>> [thurston at railay] src: g++ -v; automake --version; autoconf --version; libtool
>> --version
>> gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.10)
>> automake (GNU automake) 1.15
>> autoconf (GNU Autoconf) 2.69
>> libtool (GNU libtool) 2.4.6
>>
>> Will have to dig a bit. Maybe the option is controlled by some other flag.
>>
>> On 2018-11-26 16:30, Ken Brown wrote:
>>> Thanks.  There are still two problems:
>>>
>>> First, the syntax for the libtool '-no-undefined' flag is wrong.  It should
>>> simply be '-no-undefined' (one leading hyphen, no -Wl), as in the patch I
>>> submitted.  Otherwise, I get the following error if I try to build
>>> shared libraries:
>>>
>>> libtool:   error: can't build x86_64-unknown-cygwin shared library unless
>>> -no-undefined is specified
>>>
>>> Second, although your change takes care of the reference to rl_parse, which is
>>> the only undefined reference in a build --without-ragel, there are two further
>>> "undefined reference" errors if I build with ragel installed:
>>>
>>> .libs/libragel_la-inputdata.o: In function
>>> `InputData::checkLastRef(InputItem*)':
>>> /home/kbrown/src/ragel/src/inputdata.cc:313: undefined reference to
>>> `Parser6::terminateParser()'
>>> [...]
>>> .libs/libragel_la-inputdata.o: In function `InputData::parseKelbt()':
>>> /home/kbrown/src/ragel/src/inputdata.cc:427: undefined reference to
>>> `Scanner::do_scan()'
>>>
>>> These are defined in rlparse.cc and rlscan.cc, which aren't in the sources for
>>> libragel.
>>>
>>> Ken
>>>
>>> On 11/26/2018 11:40 AM, Adrian Thurston wrote:
>>>> Ah, sorry, I forgot to push from my private repo to the public one. There now.
>>>>
>>>> On 2018-11-25 12:11, Ken Brown wrote:
>>>>> Hi Adrian,
>>>>>
>>>>> Thanks.  Have you pushed these changes to the upstream git repo?  I'm getting
>>>>> "Already up to date" when I do "git pull".
>>>>>
>>>>> Ken
>>>>>
>>>>> On 11/25/2018 8:22 AM, Adrian Thurston wrote:
>>>>>> Hi Ken, thank you for the patches. I just enabled --no-undefined and
>>>>>> removed the
>>>>>> reference to the undefined symbol. The parse.c file cannot be included in
>>>>>> libragel because it defines the frontnend language, which is different for
>>>>>> each
>>>>>> binary in the host-* directories. All that was needed was to pass the
>>>>>> reference
>>>>>> to rl_parse into libragel from main.cc. Was already doing that for the backend
>>>>>> code generator (also a colm program).
>>>>>>
>>>>>> Adrian
>>>>>>
>>>>>> On 2018-11-16 16:58, Ken Brown wrote:
>>>>>>> I've just built ragel-7.0.0.11 on Cygwin and added it to the Cygwin
>>>>>>> distribution.  I had to patch the sources in order to build shared
>>>>>>> libraries.
>>>>>>>
>>>>>>> libtool won't build shared libraries on Cygwin unless the
>>>>>>> -no-undefined flag is given.  The first patch of this series does that
>>>>>>> for libfsm and libragel.  But it turns out that there are in fact
>>>>>>> undefined symbols in libragel.  The next two patches fix that.
>>>>>>>
>>>>>>> I don't think these patches do any harm on other platforms.
>>>>>>>
>>>>>>> Ken Brown (3):
>>>>>>>    add -no-undefined to LDFLAGS for libfsm and libragel
>>>>>>>    add dependency of libragel on libfsm and libcolm
>>>>>>>    avoid undefined symbols in libragel
>>>>>>>
>>>>>>>   src/Makefile.am | 20 ++++++++++++++------
>>>>>>>   1 file changed, 14 insertions(+), 6 deletions(-)
>>>>>>
>>>>>> _______________________________________________
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>>>>>> ragel-users at colm.net
>>>>>> http://www.colm.net/cgi-bin/mailman/listinfo/ragel-users
>>>>> _______________________________________________
>>>>> ragel-users mailing list
>>>>> ragel-users at colm.net
>>>>> http://www.colm.net/cgi-bin/mailman/listinfo/ragel-users
>>>>
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>>
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