I'm trying to use cilkscreen to detect some race conditions in a code.
I'm compiling my code using
g++-5 -g foo.cpp -fcilkplus -std=c++14 -lcilkrts -ldl -O2
However, when I launch cilkscreen I get the following error message:
cilkview ./a.out
Cilkview: Generating scalability data
Cilkview Scalability Analyzer V2.0.0, Build 4421
1100189201
Error: No Cilk code found in program
Should I add some more option to g++ ? Or does cilkscreen only works with code compiled with icc ?
FWIW: I'm using
gcc version 5.3.1 20160301 [gcc-5-branch revision 233849] (SUSE Linux)
Cilkscreen/cilkview works only with icc/icpc.
Related
I am trying to compile the example CUDA code axpy.cu from the llvm docs using:
clang++ axpy.cu -o axpy --cuda-gpu-arch=sm_86 -L/usr/local/cuda-11.2/lib64 -lcudart_static -ldl -lrt -pthread
but I'm getting the following error:
error: unable to create target: 'No available targets are compatible with triple "nvptx64-nvidia-cuda"'
What's going on here? I was able to compile CUDA with clang a day or two ago and now it's not working for some reason. I'm not sure what changed on my system.
I'm using clang 13 which should support CUDA 11.2.
The problem was that I built llvm/clang from source without support for cuda. The solution is to use the -DLLVM_TARGETS_TO_BUILD="X86;NVPTX" when building llvm from source.
I am using WSL Ubuntu. And use GCC to compile my C++ code.
I am trying to use OpenACC to parallelize my code. I heard that I can use OpenACC with GCC.
So after I install Ubuntu, I installed GCC.
And then I typed as follows:
$ g++ -fopenacc -o t testfile.cpp
As far as I know, -fopenacc should enable me to use OpenACC inside my code.
However, I got an message saying:
lto-wrapper: fatal error: could not find accel/nvptx-none/mkoffload in /usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/ (consider using ‘-B’)
So I guess I missed something.
Does anyone know how to use OpenACC with GCC?
Edited:
I tried:
sudo apt-get install gcc-9-offload-nvptx
And then the error message is now changed to:
lto1: error: ‘-fcf-protection=full’ is not supported for this target
mkoffload: fatal error: x86_64-linux-gnu-accel-nvptx-none-gcc-9 returned 1 exit status
compilation terminated.
lto-wrapper: fatal error: /usr/lib/gcc/x86_64-linux-gnu/9//accel/nvptx-none/mkoffload returned 1 exit status
compilation terminated.
/usr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
I got one step further with:
gcc-10 -O2 -ffast-math -fopenacc -fopt-info-all-omp -fcf-protection=none -foffload=nvptx laplace2dkernels.c
but just to find the next problem:
gcc-10: fatal error: GCC is not configured to support nvptx as offload target
compilation terminated
So it seems they only compiled it for AMD GCN.
If you use
gcc-10 -O2 -ffast-math -fopenacc -fopt-info-all-omp -fcf-protection=none -foffload=nvptx-none laplace2dkernels.c
>laplace2dkernels.c:74:9: optimized: assigned OpenACC seq loop parallelism
>/usr/bin/ld: /tmp/ccYd0cZe.crtoffloadtable.o: warning: relocation against >`__offload_vars_end' in read-only section `.rodata'
It compiles but then when running it misses:
libgomp: while loading libgomp-plugin-gcn.so.1: libgomp-plugin-gcn.so.1: cannot open shared object file: No such file or directory
I do not need to install those libraries because I want to get it to run with my Nvidia card.
With the PGI compilers everything worked fine.
NOTE: I am also using WSL and special NVIDIA drivers to allow for GPU passthrough.
Here's what worked for me for a Tiny C++ stencil code with OpenACC directives, after installing gcc-10-offload-nvptx:
g++ -c -g -O -fopenacc -foffload=nvptx-none -fcf-protection=none -foffload=-misa=sm_35 -fno-stack-protector stencil_acc.cxx
g++ -o stencil_acc -g -O -fopenacc -foffload=nvptx-none -fcf-protection=none -foffload=-misa=sm_35 -fno-stack-protector util.o stencil_acc.o
I am trying to run the makefile of a program in Fortran 77 that I did not write.
It specifies the following flags:
FLT_FLAGS = -native -libmil
and then uses them to compile a Fortran 77 program:
f77 -O -native -libmil -c a2.f
but fails:
f77: error: unrecognized command line option ‘-native’
makefile:107: recipe for target 'vg.a(a2.o)' failed
make: *** [vg.a(a2.o)] Error 1
The only thing I have been able to find with respect to this issue is that -native is obsolete, and maybe that's why gfortran (f77) does not recognize it: https://docs.oracle.com/cd/E37069_01/html/E37076/aevft.html#scrolltoc
You are using gfortran version 5.4. I wouldn't call f77 but gfortran directly if I were you.
The correct gfortran option similar to -native in some other compilers is -march=native or -mtune=native. See the manual and GCC: how is march different from mtune?
Don't forget to use other optimization flags like -O2 or -O3. The native option alone is not too useful.
My Xcode 9.2 has the option to compile C++ using: -std=c++17 or -std=gnu++17.
My C++ code that has some C++17 features compiles successfully.
However, if I try to compile the same code in my Terminal using the same flags, I get the following errors:
clang++ -std=c++17 test.cpp -o test
error: invalid value 'c++17' in '-std=c++17'
and
clang++ -std=gnu++17 test.cpp -o test
error: invalid value 'gnu++17' in '-std=gnu++17'
My OSX version is 10.13.3 and my Clang++ version is:
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin17.4.0
I thought that Terminal would use the same compiler from Xcode. That may be the case, but I can't use the same options. At least I couldn't.
I tried using -std=C++1z, but it didn't compile my code because it doesn't understand some new features from C++17.
So my question is: Is there a way to use -std=c++17 or -std=gnu++17 that are currently available in my Xcode 9.2, in my Terminal app?
This questions is not the same as the others available at stackoverflow because all the answers I found the -std=c++17options was not available in Xcode. Now we have this options, but I can't figure out how to use it in Terminal.
The compiler Apple currently ships with Xcode 9.2 (clang-900.0.39.2) does not support the -std=c++17 flag.
Xcode uses the -std=c++1z flag when you enable c++17 support. If you want to use -std=c++17 you need to manually install clang. You could do that using brew install llvm (assuming you have homebrew installed).
You can compile your program with
/usr/local/Cellar/llvm/5.0.0/bin/clang++ -std=c++17 test.cpp -o test
You change the symlinks in usr/bin/clang++ to point at the new destination if you don't want to use the full path to the compiler.
The compiler which is shipped with Xcode 9.3 will be
Apple LLVM version 9.1.0 (clang-902.0.30)
This can handle the -std=c++17 flag.
I working on trying to compile a code written in C++ and Root on my Mac. The code is from a colleague who works on a Linux laptop. In addition to the different OS's, I have both a different version of gcc and Root than her and I am not sure which difference is causing the code not to compile on my machine.
She has g++ 4.8 and root 5.(something). I have gcc 5.3.0 and root 6.06/02.
She has given to me the a line of code she uses to get her machine to compile the code
gcc -Wall -o executable_name code_name.cc `root-config --cflags --glibs`
But when I write on my machine, Terminal gives me the error
gcc: error: unrecognized command line option ‘-stdlib=libc++’
gcc: error: unrecognized command line option ‘-stdlib=libc++’
I need help generating the correct line to get gcc to compile the code.
The problem here is two-fold: You're on OSX and you are using GCC.
The problem with this is that root-config assumes that since you're on OSX you will be using the OSX-standard Clang compiler which have the -stdlib flag. Since you're not using Clang, but GCC (which doesn't have this flag) you get an error.
You have two possible solutions: Use clang++ instead of g++ to compile and build (requires you to install the compiler if it's not installed already, it comes with Xcode), or to modify the root-config script so it doesn't add -stdlib=libc++. There might be environment variables or flags that the root-config script checks that alter the behavior, but I don't know anything about the script, you have to check it for that.