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

Adrian Thurston thurston at colm.net
Wed Nov 28 09:15:59 UTC 2018 

Ok, I guess we check for cygwin and use the appropriate option. I don't 
normally build on cygwin so I would like to enforce it on linux as well.

On 2018-11-28 00:03, Ken Brown wrote:
> 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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