Re: MSYS+MSVC for libtool branch-2-0, take 7

[Ralf Wildenhues]

Hi Peter,

* Peter Ekberg wrote on Thu, Aug 11, 2005 at 11:38:59AM CEST:
> 
> Anyway, here's testsuite.log and I configured with:
> ../configure CC=cl CFLAGS=-MD CXX=cl CXXFLAGS=-MD STRIP=: RANLIB=:
> F77=no FC=no NM="dumpbin -symbols" AR=lib LD=link

OK, how about this suggestion:

After addressing my comments below, if you feel comfortable, please go
ahead and check this patch (or split-up patches) in for HEAD.  That way
it may be easier for other people to test, too.  After the testsuite
failures have been ironed out, and it has been used to successfully
build a few real-world packages, we put a backport in branch-2-0 (I can
help with backporting, if you like).  If HEAD turns up severely broken
with this patch, we can still revert it later.

Would that be ok with you?  Does one of the other maintainers
disapprove?


Missing bits and noted to the patch:

A ChangeLog entry.  :)
(be sure to note all new TAGVARs)

Please add a NEWS entry stating much improved but still experimental
support for MSVC.

Please also note that lt_error_list suffers from the same failure as
preloaded_symbols.  I have not checked how a possible fix should look
like (this applies to mingw/gcc as well).

All over the patch, you sometimes use 'sed' instead of '$SED'.
In places where you cannot control the contents of stdin, you should
change that to $SED.


config/ltmain.m4sh:

| @@ -5009,7 +5079,35 @@
|             fi
|           done
|           IFS="$save_ifs"
| -         if test -n "$export_symbols_regex"; then
| +         case $host_os/$with_gcc/$skipped_export in
| +         mingw*/no/: | mingw*//: | cygwin*/no/: | cygwin*//:)
| +           # Assume MSVC _and_ lib archiver interface...
| +           # Build a lib using a command file and export symbols from
| +           # the lib instead of from the objects individually.
| +           skipped_export=false
| +           :>$output_objdir/$libname.symlibcmd
| +           for obj in $libobjs; do
| +             $ECHO \""$obj"\" >> $output_objdir/$libname.symlibcmd
| +           done

Please use only one redirection here, it should be faster:

skipped_export=false
for obj in $libobjs; do
  $ECHO "\"$obj\""
done >"$output_objdir/$libname.symlibcmd"

Similarly for file archive linking.
(The only thing one has to remember with redirected loops is that very
old shells might fork and thus variable assignments inside will not
propagate.)


| +           $RM $output_objdir/$libname.symlib
| +           func_show_eval '$AR $AR_FLAGS 
${AR_OFLAGS}$output_objdir/$libname.symlib @$output_objdir/$libname.symlibcmd'
| +           save_libobjs="$libobjs"
| +           libobjs="$output_objdir/$libname.symlib"
| +           # Rerun export_symbols_cmds
| +           $run $RM $export_symbols

This:
| +           cmds=$export_symbols_cmds
| +           save_ifs="$IFS"; IFS='~'
| +           for cmd in $cmds; do
| +             IFS="$save_ifs"
| +             eval cmd=\"$cmd\"
| +             func_show_eval "$cmd" 'exit $?'
| +           done
| +           IFS="$save_ifs"

Can be reduced to
  func_execute_cmds "$export_symbols_cmds" 'exit $?'

| +           libobjs="$save_libobjs"
| +           ;;
| +         esac
| +         # No use to run $export_symbols_regex if exports are skipped...
| +         if test "X$skipped_export" != "X:" && test -n 
"$export_symbols_regex"; then
|             func_show_eval '$EGREP -e "$export_symbols_regex" 
"$export_symbols" > "${export_symbols}T"'
|             func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
|           fi
| 



| @@ -6074,7 +6204,11 @@
|         # are only useful if you want to execute the "real" binary.
|         # Since the "real" binary is built for $host, then this
|         # wrapper might as well be built for $host, too.
| -       $opt_dry_run || $LTCC $LTCFLAGS -s -o $cwrapper $cwrappersource
| +       if test "$with_gcc" = "yes"; then
| +         $opt_dry_run || $LTCC $LTCFLAGS -s -o $cwrapper $cwrappersource
| +       else
| +         $opt_dry_run || $LTCC $LTCFLAGS -o $cwrapper $cwrappersource
| +       fi
|         ;;
|       esac
|       $RM $output

Does the following work too?  Should we not use it then?
(Or is there a severe performance penalty involved for gcc?)

$opt_dry_run || {
   $opt_dry_run || $LTCC $LTCFLAGS -o $cwrapper $cwrappersource
   $STRIP $cwrapper
}



m4/libtool.m4:

| @@ -2840,7 +2946,8 @@
|  m4_require([_LT_DECL_EGREP])dnl
|  
|  # Check for command to grab the raw symbol name followed by C symbol from nm.
| -AC_MSG_CHECKING([command to parse $NM output from $compiler object])
| +# $compiler is not yet set, fall back to $CC.
| +AC_MSG_CHECKING([command to parse $NM output from $CC object])
|  AC_CACHE_VAL([lt_cv_sys_global_symbol_pipe],
|  [
|  # These are sane defaults that work on at least a few old systems.

Why is this change needed?  AFAICS, the output should be identical.


old test suite changes:

| --- tests/demo/foo.h  22 Apr 2005 10:10:31 -0000      1.2
| +++ tests/demo/foo.h  11 Aug 2005 08:50:21 -0000
| @@ -33,6 +33,12 @@
|  #  endif
|  #endif
|  
| +#ifdef _MSC_VER
| +# define EXTERN extern __declspec(dllimport)
| +#else
| +# define EXTERN extern
| +#endif
| +
|  /* __BEGIN_DECLS should be used at the beginning of your declarations,
|     so that C++ compilers don't mangle their names.  Use __END_DECLS at
|     the end of C declarations. */

I don't like this.  I also don't think it is correct.
Look at tests/pdemo/foo.h for other occurrences of EXTERN, which I
don't like either.  Try to make the definitions match.

This is something we need to get right once (maybe in combination with
Automake), and then provide a portable way to users.  Same with the
mdemo2 failure.  You could think about applying the patch without these
old testsuite changes for now.


Notes to the testsuite output:
stresstest:
| libtool: link: creating main
| lt-main.c
| ./.libs/lt-main.c(98) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(99) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(105) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(115) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(167) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(200) : warning C4002: too many actual parameters for macro 
'DEBUG'
| ./.libs/lt-main.c(252) : warning C4047: '==' : 'int ' differs in levels of 
indirection from 'void *'
| ./.libs/lt-main.c(275) : warning C4047: '==' : 'int ' differs in levels of 
indirection from 'void *'

This looks like your change to the cwrappersource in ltmain somehow did
not work out correctly.  Could you look into this?

Independently, you changed some preprocessor constructs there -- could
you fix the indentation like this?
#if foo
# bar
#else
# if other
#  baz
# endif
#endif


The following, however, is probably the failure which also happens
on mingw/gcc and cygwin:

| dlself.def : error LNK2001: unresolved external symbol w1$
| dlself.def : error LNK2001: unresolved external symbol w10$

Cheers, and thanks for all your work,
Ralf