[llvm-commits] [llvm] r86955 - in /llvm/trunk: Makefile.config.in autoconf/configure.ac configure include/llvm/Config/config.h.in

[Óscar Fuentes]

Rafael Espindola <espindola at google.com>
writes:

>> Probably not. The way gcc does this is by having each major
>> subdirectory have a configure script that run by make. We could also
>> try to allow projects to have macros that are included at configure
>> creation time.  The second option avoids having a second annoying
>> configure script in the build ...
>
> Or we could switch to cmake :-)

That would make a lot of sense, but as my skin is not bullet-proof, I
will not be the first one making the proposal on llvm-dev :-)

> What are the missing features of the cmake based build system?

Now that testing works, there is no major feature missing,
AFAIK. configure has some extra knobs, but those can be easily
implemented on cmake.

> It looks easier to handle config.h generation in cmake than in
> autoconf.
>
> Does cmake support non-recursive makes? Not that we use one for llvm
> now, but it is nice not to drop the possibility of doing it.

You shouldn't care about how the inners of cmake work. Specifically, the
user is advised to *not* look at the makefiles.

So far my experience indicates that performance is similar to the
configure build, and having dependencies right is quite easy, given the
complexity of the LLVM build. Maintenance of the cmake LLVM build system
is easier than maintaining the old single Makefile that my compiler
project used, and that only provided support for 6 compilers on 2
platforms.

-- 
Óscar