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Compiling with -fopenmp-targets=nvptx64-nvida-cuda generates fatal error: 'gnu/stubs-32.h' file not found #32390

Open llvmbot opened 7 years ago

llvmbot commented 7 years ago
Bugzilla Link 33043
Version unspecified
OS Linux
Attachments Verbose error
Reporter LLVM Bugzilla Contributor
CC @alexey-bataev,@hahnjo,@hfinkel

Extended Description

Dear All,

I'm getting the following error when compiling with triple nvptx64-nvida-cuda. I'm trying to compile manually one of the test cases in libomptarget (openmp/libomptarget/test/offloading/offloading_success.c).

clang -fopenmp -fopenmp-targets=nvptx64-nvida-cuda offloading_success.c

But I'm getting the following compilation error during the compilation of the ptx code. For some reason the compiler is trying to use the gnu/stubs-32.h header (it is using the macro __WORDSIZE == 32 rather than 64). I'm attaching the verbose output of the compiler.

In file included from offloading_success.c:6: In file included from /usr/include/stdio.h:28: In file included from /usr/include/features.h:385: /usr/include/gnu/stubs.h:7:11: fatal error: 'gnu/stubs-32.h' file not found

include <gnu/stubs-32.h>

      ^~~~~~~~~~~~~~~~

1 error generated.

I tested this in two 64 bit systems, thus I don't understand why It wants to use a 32 bit header:

------Setup I compiled llvm/clang/OpenMP from the master branch. LLVM/clang compiles correctly and OpenMP compiles with LIBOMPTARGET: Building CUDA offloading plugin.

Clang commit: 84f57d869ba15eb9b12abc57014d530647a00e01 LLVM commit: 34ad4ae9219da7d2e14b14d0eefd10515d5ac526 OpenMP commit: 1eb73292d2baee506f5dcd1584fca768c849313b

I used cmake + ninja.

  1. LLVM + clang: cmake /home/1678/Code/ornl/llvm -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_INSTALL_PREFIX=/home/1678/Code/ornl/llvm-install

  2. OpenMP as an out-of-the-tree project: cmake /home/1678/Code/ornl/llvm-out-of-tree/openmp -G Ninja -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/home/1678/Code/ornl/llvm-oot-install -DLIBOMP_LLVM_LIT_EXECUTABLE=/home/1678/Code/ornl/llvm-build/bin/llvm-lit -DLIBOMPTARGET_FILECHECK_EXECUTABLE=/home/1678/Code/ornl/llvm-build/bin/FileCheck -DLIBOMPTARGET_LLVM_LIT_EXECUTABLE=/home/1678/Code/ornl/llvm-build/bin/llvm-lit -DLIBOOMPTARGET_OPENMP_HEADER_FOLDER=/home/1678/Code/ornl/llvm-oot-install/include -DLIBOMPTARGET_OPENMP_HOST_RTL_FOLDER=/home/1678/Code/ornl/llvm-oot-install/lib

Best,

hahnjo commented 6 years ago

Some of the patches have landed. Can you please retry if you still see the error? Also if you are compiling for 32bit host, the correct triple is nvptx-nvidia-cuda, not nvptx64-nvidia-cuda (see https://llvm.org/docs/NVPTXUsage.html)

llvmbot commented 7 years ago

Hi Hal,

To my understanding the error will go away once the outstanding OpenMP offload driver patches land. There are currently 10 accepted patches and 3 that have yet to be accepted.

Thanks,

--Doru

hfinkel commented 7 years ago

As I recall, the problem is that, when compiling for the target (nvptx64), we're not defining the host-associated preprocessor macros (e.g. __X86_64 or powerpc64__). As a result, when we end up in code like this:

$ cat /usr/include/bits/wordsize.h / Determine the wordsize from the preprocessor defines. /

if defined __x86_64 && !defined ILP32__

define __WORDSIZE 64

else

define __WORDSIZE 32

endif

we end up setting __WORDSIZE == 32 and, thus, trying to include 32-bit headers (which are often not installed).

I suspect that the real answer here is to make sure that we pick up the CUDA stdio.h, etc. when compiling for a nvptx target target (or something along those lines). Alternatively, we could also define the host architecture macros when compiling for the target.