[cfe-dev] Problem building llvm and clang 7.0.0

[Fletcher, John P via cfe-dev]

_______________________________________
From: Jonas Hahnfeld [hahnjo at hahnjo.de]
Sent: 10 August 2018 18:08
To: Fletcher, John P
Cc: cfe-dev ‎[cfe-dev at lists.llvm.org]‎
Subject: Re: [cfe-dev] Problem building llvm and clang 7.0.0

On 2018-08-10 18:34, Fletcher, John P via cfe-dev wrote:
> I am building LLVM and Clang using gcc 7.1 with Cmake and Ninja on a
> system based on Ubuntu 12.04.
>
> The following commands worked for clang 6.0.0 with all the source
> files installed:
>
> /opt/cmake/bin/cmake -GNinja \
> -DCMAKE_C_COMPILER=/opt/gcc-7.1/bin/gcc \
> -DCMAKE_CXX_COMPILER=/opt/gcc-7.1/bin/g++ \
> -DGCC_INSTALL_PREFIX=/opt/gcc-7.1 \
> -DCMAKE_INSTALL_PREFIX=/home/fletcher/LLVM/llvm-6.0.distrib/local
> -DCMAKE_BUILD_TYPE=Release -DLLVM_BUILD_LLVM_DYLIB=ON
> -DLLVM_TARGETS_TO_BUILD="host" -DLLVM_PARALLEL_LINK_JOBS=1
> -DCMAKE_EXE_LINKER_FLAGS="-Xlinker -R/opt/gcc-7.1/lib64
> -L/opt/gcc-7.1/lib64" ../llvm
>
> Some things seem to have changed with version 7.0.0
>
> (1)  There has been a change associated with libomptarget and now it
> fails as it is picking up an old version of cuda on my computer and
> complaining that the gcc is too new.  The only way I could find to get
> rid of this is to remove openmp.

libomptarget uses the default FindCUDA.cmake. Can you try setting
CUDA_TOOLKIT_ROOT_DIR and / or CUDA_BIN_PATH to pont to the "right"
version of CUDA?
Alternatively you can point LIBOMPTARGET_NVPTX_ALTERNATE_HOST_COMPILER
to an older version of GCC that is compatible with the detected version
of CUDA.

Cheers,
Jonas

------------------------

Jonas

Thank you for your suggestion.  I have tried various things and in the end I have renamed my out of date link to cuda as cudaold so that it is no longer picked up.  That is not enough as it still fails in openmp so I have taken that out.

To the CLANG community.

(1) I am concerned that something has changed and I cannot find any documentation, in particular something which worked does not and is NOT picked up by Cmake so that it crashes after 2.5 hours of running.  What is it that has changed?

(2) There has been no response on this problem.
-------
(2) When I did this it still does not build as it cannot link a library with the following messages:

FAILED: lib/clang/7.0.0/lib/linux/libclang_rt.fuzzer_no_main-x86_64.a
--localize-hidden: not found

--localize-hidden seems to be an option for ld.  I have not traced any documentation.
--------
I now think that the problem about --localize-hidden: not found is because it should be preceded by objcopy, for which it is an argument, so that something in the command processing is broken. 

I am spending my time building on rc1 to help you get things sorted.  Where are you all?

Someone knows what you have changed.

Thank you

John