[Unison-hackers] Compiling under Mac OS X

[Benjamin Pierce]

> First thing, I think you can remove the dependency on unison-blob.o
> from target macexecutable in Makefile.OCaml.  At the moment, the Caml
> files are compiled twice!  Replace the line:
>
>        macexecutable: $(NAME)-blob.o
>
> by just
>
>        macexecutable:
>

OK, done.

> Then, the patch had zero chance of working: the problem seems to
> happen at an earlier stage, when the Caml code is linked, not when the
> GUI is built.  Can you try this, then:
>
>> make clean
>> export ZERO_LINK=NO
>> make

Same failure.  :-(

>
> If this still does not work, we have to investigate a bit more.  The
> compilation process fails at the final step when linking everything
> together.  The reason is that the two symbols below are not found:
>
>> Undefined symbols:
>>   "_caml_apply2", referenced from:
>>       _caml_callback2_exn in libasmrun.a(i386.o)
>>   "_caml_apply3", referenced from:
>>       _caml_callback3_exn in libasmrun.a(i386.o)
>
> These symbols should come from file unison-blob.o .  You can check
> they are indeed defined there with the following command:
>
>> nm unison-blob.o | grep caml_apply2
>        0000000000005000 T caml_apply2
>        0000000000003ef0 T caml_apply21
>        0000000000003b70 T caml_apply23
>        00000000000037c0 T caml_apply24

Output is a little different from yours:

   ~/current/unison/trunk/src> nm unison-blob.o | grep caml_apply2
   000024b0 t _caml_apply2

But it looks like the one that the loader can't find is defined, at  
least.

> If the symbols are not defined, we need to find out at which point
> they disappear.  You need to change this rule:
>
>        $(NAME)-blob.o: $(CAMLOBJS) $(COBJS)
>                @echo Linking $@
>                $(CAMLC) -output-obj -verbose $(CAMLFLAGS) ...
>                $(LD) -r -o $@ u-b.o $(COBJS)
>                $(RM) u-b.o
>
> into:
>
>        $(NAME)-blob.o: $(CAMLOBJS) $(COBJS)
>                @echo Linking $@
>                $(CAMLC) -dstartup -output-obj -verbose $ 
> (CAMLFLAGS) ...
>                $(LD) -r -o $@ u-b.o $(COBJS)
>
> (Add a "-dstartup" option to ocamlopt and remove the "rm" command.)
>
> Then, if you recompile, you should get two files u-b.o.startup.s and
> u-b.o in the build directory.  Then, again, you can use "nm u-b.o" to
> find out whether caml_apply2 is defined in u-b.o.  In the assembly
> file, there should be some lines that look like this:
>
>        [...]
>                .text
>                .align  16
>                .globl  caml_apply2
>        caml_apply2:
>                subq    $8, %rsp
>        [...]
>
> Tell me the last point where you could find caml_apply2 defined (the
> corresponding output could be useful too).
>
> Now, if the symbols are actually defined in unison-blob.o, this may be
> a problem with the order in which the files are given to gcc for
> linking.  So, in the following command (that should be a single line),
> you can try to move unison-blob.o before -lasmrun.  (Under Linux, I
> have to put it before all the -lxxx, but this may different under
> Mac OS X.)
>
>>     /Developer/usr/bin/gcc-4.0 -arch i386 -isysroot /Developer/SDKs/
>> MacOSX10.5.sdk -L/Users/bcpierce/current/unison/trunk/src/uimacnew/
>> build/Default -F/Users/bcpierce/current/unison/trunk/src/uimacnew/
>> build/Default -F/Users/bcpierce/current/unison/trunk/src/uimacnew -
>> filelist /Users/bcpierce/current/unison/trunk/src/uimacnew/build/
>> uimacnew.build/Default/uimac.build/Objects-normal/i386/
>> Unison.LinkFileList -mmacosx-version-min=10.5 -L/usr/local/lib/ 
>> ocaml -
>> lunix -lthreadsnat -lstr -lbigarray -lasmrun -framework Cocoa -
>> framework Security -framework Growl -framework ExceptionHandling /
>> Users/bcpierce/current/unison/trunk/src/uimacnew/../unison-blob.o - 
>> o /
>> Users/bcpierce/current/unison/trunk/src/uimacnew/build/Default/
>> Unison.app/Contents/MacOS/Unison

Moving it earlier doesn't seem to help, unfortunately.

~/current/unison/trunk/src> /Developer/usr/bin/gcc-4.0 -arch i386 - 
isysroot /Developer/SDKs/MacOSX10.5.sdk -L/Users/bcpierce/current/ 
unison/trunk/src/uimacnew/build/Default -F/Users/bcpierce/current/ 
unison/trunk/src/uimacnew/build/Default -F/Users/bcpierce/current/ 
unison/trunk/src/uimacnew -filelist /Users/bcpierce/current/unison/ 
trunk/src/uimacnew/build/uimacnew.build/Default/uimac.build/Objects- 
normal/i386/Unison.LinkFileList -mmacosx-version-min=10.5 -L/usr/local/ 
lib/ocaml /Users/bcpierce/current/unison/trunk/src/uimacnew/../unison- 
blob.o -lunix -lthreadsnat -lstr -lbigarray -lasmrun -framework Cocoa - 
framework Security -framework Growl -framework ExceptionHandling  -o / 
Users/bcpierce/current/unison/trunk/src/uimacnew/build/Default/ 
Unison.app/Contents/MacOS/Unison
Undefined symbols:
   "_caml_apply2", referenced from:
       _caml_callback2_exn in libasmrun.a(i386.o)
   "_caml_apply3", referenced from:
       _caml_callback3_exn in libasmrun.a(i386.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status
~/current/unison/trunk/src> /Developer/usr/bin/gcc-4.0 -arch i386 - 
isysroot /Developer/SDKs/MacOSX10.5.sdk -L/Users/bcpierce/current/ 
unison/trunk/src/uimacnew/build/Default -F/Users/bcpierce/current/ 
unison/trunk/src/uimacnew/build/Default -F/Users/bcpierce/current/ 
unison/trunk/src/uimacnew /Users/bcpierce/current/unison/trunk/src/ 
uimacnew/../unison-blob.o -filelist /Users/bcpierce/current/unison/ 
trunk/src/uimacnew/build/uimacnew.build/Default/uimac.build/Objects- 
normal/i386/Unison.LinkFileList -mmacosx-version-min=10.5 -L/usr/local/ 
lib/ocaml -lunix -lthreadsnat -lstr -lbigarray -lasmrun -framework  
Cocoa -framework Security -framework Growl -framework  
ExceptionHandling  -o /Users/bcpierce/current/unison/trunk/src/ 
uimacnew/build/Default/Unison.app/Contents/MacOS/Unison
Undefined symbols:
   "_caml_apply2", referenced from:
       _caml_callback2_exn in libasmrun.a(i386.o)
   "_caml_apply3", referenced from:
       _caml_callback3_exn in libasmrun.a(i386.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status


Any more thoughts?

    - B