[LLVMdev] Building llvm from source with clang instead of gcc

[Edward Diener]

On 01/05/2013 01:11 PM, Dmitri Gribenko wrote:
> On Sat, Jan 5, 2013 at 7:48 PM, Edward Diener
> <eldlistmailingz at tropicsoft.com>  wrote:
>> I actually found out that llvm/configure will choose clang if it is
>> found in the path. This contradicts what is written at
>> http://llvm.org/docs/GettingStarted.html#requirements, where it says it
>> will use the first GCC it finds. Perhaps that explanation needs to be
>> updated.
>
> Updated docs in r171630.
>
>> Finally I found that if llvm/configure uses clang instead of gcc, it
>> invariably fails on my Linux distros because it is using the gcc
>> distributed included directories and an earlier version of clang will
>> often fail with these gcc header files. Once I force llvm/configure to
>> use gcc, building llvm/clang succeeds again.
>
> Right.  Maybe we need to skip old clang versions in this case.

I think this should be done until clang can use its own header files and 
libraries, when it is installed as a binary, rather than the ones that 
gcc installs. In fact I am a bit amazed that clang does not already have 
its own header files and libraries for use when one tries llvm/configure 
and it sets up llvm's build system to use clang as its compiler. Is this 
the fault of clang or is it the fault of the llvm/configure system ?