[cfe-dev] [libcxx] build system questions

[Michael Spencer]

On Tue, Dec 7, 2010 at 7:55 PM, Howard Hinnant <hhinnant at apple.com> wrote:
> On Dec 7, 2010, at 7:49 PM, Michael Spencer wrote:
>
>> On Mon, Dec 6, 2010 at 9:06 AM, Howard Hinnant <hhinnant at apple.com> wrote:
>>> I think we should start out with a simple question:  What problem are we attempting to solve?
>>>
>>> -Howard
>>
>> If we want Windows support (which I do :P), CMake is the way to go.
>> I'm willing to do it, targeting POSIX-like platforms for now, as doing
>> a Windows port is a much larger project. It's also possible to do it
>> without requiring explicit source lists, even though there aren't that
>> many to begin with.
>
> Windows support seems motivating to me.  The build system will probably be the easy part.  locale support will be more challenging.  Another challenging part may be the low-level stuff such as type_info and exception_ptr.
>
> -Howard

locale will be a lot of work, but not too hard. type_info should be
easy for clang, but hard for MSVC (if we even plan to support MSVC).
I'm afraid to look at exception_ptr :P. LLVM/Clang can't even do
exceptions on Windows currently.

I've attached a very rough patch for Linux CMake support. It has a few
hard coded paths for my system which will need to be configured by
CMake instead. It compiles with both g++ and clang++, however, the lit
tests only work with g++ because clang++ doesn't understand
-nodefaultlibs.

I just finished running all the tests. 2506 out of 4217 passed (~60%).
Most failures are due to undefined references, and the rest are due to
-fno_exceptions or -fno-rtti which I had to set because
__gxx_personality_v0 is part of libstdc++ (I also set
_LIBCXX_NO_{EXCEPTIONS,RTTI}, but it doesn't always seem to be
honored).

TODO:
* Fix RPATH for shared libraries. I gave up and made it static.
* Add support for host and target triples, and auto-select host.
* Support Darwin
* Add CMake options for all the features.
* Configure the lit test config for the build or install dir
* Make clang honor -nodefaultlibs
* Figure out what libs are needed on Linux.
* Add "make check"

- Michael Spencer
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