David Majnemer 5a1a1856a4 Windows: Add support for unicode command lines
Summary:
The MSVCRT deliberately sends main() code-page specific characters.
This isn't too useful to LLVM as we end up converting the arguments to
UTF-16 and subsequently attempt to use the result as, for example, a
file name.  Instead, we need to have the ability to access the Unicode
command line and transform it to UTF-8.

This has the distinct advantage over using the MSVC-specific wmain()
function as our entry point because:
 - It doesn't work on cygwin.
 - It only work on MinGW with caveats and only then on certain versions.
 - We get to keep our entry point as main(). :)

N.B.  This patch includes fixes to other parts of lib/Support/Windows
s.t. we would be able to take advantage of getting the Unicode paths.
E.G.  clang spawning clang -cc1 would want to give it Unicode arguments.

Reviewers: aaron.ballman, Bigcheese, rnk, ruiu

Reviewed By: rnk

CC: llvm-commits, ygao

Differential Revision: http://llvm-reviews.chandlerc.com/D1834

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192069 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-06 20:25:49 +00:00
..

Upgrading Libtool
===============================================================================

If you are in the mood to upgrade libtool, you must do the following:

 1. Get the new version of libtool and put it in <SRC>
 2. configure/build/install libtool with --prefix=<PFX>
 3. Copy <SRC>/ltdl.m4 to llvm/autoconf/m4
 4. Copy <PFX>/share/aclocal/libtool.m4 to llvm/autoconf/m4/libtool.m4
 5. Copy <PFX>/share/libtool/ltmain.sh to llvm/autoconf/ltmain.sh
 6. Copy <PFX>/share/libtool/libltdl/ltdl.c to llvm/lib/System
 7. Copy <PFX>/share/libtool/libltdl/ltdl.h to llvm/lib/System
 8. Edit the ltdl.h file to #include "llvm/Config/config.h" at the very top. You
    might also need to resolve some compiler warnings (typically about
    comparison of signed vs. unsigned values). But, you won't find out about 
    those until you build LLVM (step 13).
 9. Edit the llvm/autoconf/m4/libtool.m4 file so that:
    a) in AC_PROB_LIBTOOL macro, the value of LIBTOOL is set to
       $(top_builddir)/mklib, not $(top_builddir)/libtool
    b) in AC_LIBTOOL_SETUP macro, the variable default_ofile is set to 
       "mklib" instead of "libtool"
    c) s/AC_ENABLE_SHARED_DEFAULT/enable_shared_default/g
    d) s/AC_ENABLE_STATIC_DEFAULT/enable_static_default/g
    e) s/AC_ENABLE_FAST_INSTALL_DEFAULT/enable_fast_install_default/g
10. Run "autoupdate libtool.m4 ltdl.m4" in the llvm/autoconf/m4 directory.
    This should correctly update the macro definitions in the libtool m4 
    files to match the version of autoconf that LLVM uses. This converts
    AC_HELP_STRING to AS_HELP_STRING and AC_TRY_LINK to AC_LINK_IFELSE, amongst
    other things. You may need to manually adjust the files.
11. Run AutoRegen.sh to get the new macros into configure script
12. If there are any warnings from AutoRegen.sh, go to step 9.
13. Rebuild LLVM, making sure it reconfigures
14. Test the JIT which uses libltdl
15. If it all works, only THEN commit the changes.

Upgrading autoconf
===============================================================================

If you are in the mood to upgrade autoconf, you should:

 1. Consider not upgrading.
 2. No really, this is a hassle, you don't want to do it.
 3. Get the new version of autoconf and put it in <SRC>
 4. configure/build/install autoconf with --prefix=<PFX>
 5. Run autoupdate on all the m4 macros in llvm/autoconf/m4
 6. Run autoupdate on llvm/autoconf/configure.ac
 7. Regenerate configure script with AutoRegen.sh
 8. If there are any warnings from AutoRegen.sh, fix them and go to step 7.
 9. Test, test, test.