[cfe-users] Confusion about building llvm/clang

[Edward Diener]

On 01/05/2013 09:52 AM, Dmitri Gribenko wrote:
> On Sat, Jan 5, 2013 at 7:01 AM, Edward Diener
> <eldlistmailingz at tropicsoft.com> wrote:
>> In the instructions at http://clang.llvm.org/get_started.html it says that
>> after the initial run of 'llvm/configure' and 'make' I can subsequentally
>> build clang from the clang directory level. This makes sense, but does this
>> work after I update both llvm and clang ?
>>
>> Later on, however, the instructions say:
>>
>> "Once you have checked out Clang into the llvm source tree it will build
>> along with the rest of llvm. To build all of LLVM and Clang together all at
>> once simply run make from the root LLVM directory."
>>
>> This is confusing. I thought running 'make' from the clang directory level
>> will build all of llvm and clang since clang depends on llvm. What am I
>> missing here ?
> 
> Running make from tools/clang will only rebuild clang, even if some
> files in llvm/ were changed and need to be rebuilt.  This can lead to
> an inconsistent build and weird errors.  To be safe, to update the
> working copy one should 'svn up' both repositories and run make in the
> root build directory.

Since clang supposedly is synced to llvm, the getting started
instructions should never tell the end-user to run 'make' from
tools/clang if the needed parts of llvm are not rebuilt in that case.
Thanks for the heads up about this ! I always do update llvm and clang
at the same time to get the latest u0pdates and now I know always to run
'make' from the root build directory.