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

Wed Nov 28 10:12:55 UTC 2018

Rather than check for Cygwin, I think you can just use

   -Wl,--no-undefined -no-undefined

on all platforms.  That works fine on Cygwin, and I think it should work on 
Linux too.  libtool is happy to see '-no-undefined' on Cygwin and probably 
doesn't care about it on Linux, while '-Wl,--no-undefined' shows up in the link 
command on all platforms (and is redundant on Cygwin).

Ken

On 11/28/2018 9:15 AM, Adrian Thurston wrote:
> 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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