I am trying to use gcov on Linux(Ubuntu) to see frequency of execution for each line of source.
I have added following flags to my gcc compiler and linker flags,
CCFLAGS = -fprofile-arcs -ftest-coverage
LDFLAGS = -fprofile-arcs -lgcov
but after compiling and running the program, i see no *.gcda file created. As a result of which when i run
gcov --object-directory <path to the *.gcno/*.gcda files> myfile.cpp
Shows error:
myfile.gcda:cannot open data file, assuming not executed
File '../../../../../code/myfile.cpp'
Lines executed:0.00% of 2625
Am i missing something. How to fix this?
You can use __gcov_flush() method inside your code.
You will need to invoke this from registered signal handler.
See:
https://www.osadl.org/fileadmin/dam/interface/docbook/howtos/coverage.pdf
Using this, you can keep your service running and issue "kill" whenever you need to dump coverage data.
Hope that helps....
make sure the gcov and gcc are of the same version :), this where many of the people fail to check.
$gcc --version
gcc (GCC) 4.1.1
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ find /usr/lib/gcc -name libgcov.a
/usr/lib/gcc/x86_64-redhat-linux/4.1.1/32/libgcov.a
/usr/lib/gcc/x86_64-redhat-linux/4.1.1/libgcov.a
/usr/lib/gcc/x86_64-redhat-linux/3.4.6/32/libgcov.a
/usr/lib/gcc/x86_64-redhat-linux/3.4.6/libgcov.a
so the gcc version you have loaded should be atleast in the available list of libgcov.a
Related
I want to set default compiler from clang to gcc in termux (android application).
gcc isn't available in official repo so I used pointless community repo. But now I can't configure the termux to use gcc instead of clang.
usr/bin/ contain g++, gcc, gcc-8, g++8.
But gcc --version command shows default clang.
gcc-8 --version shows:
"CANNOT LINK EXECUTABLE "gcc-8" : library "libc++_shared.so" not found
linker: CANNOT LINK EXECUTABLE "gcc-8": library "libc++_shared.so" not found.
I had this problem as well. The question that is asked by #Andy J is unfortunately less than helpful because there is not even ldconfig in this environment and I saw on Reddit that one of the developers said it's not even needed. (I doubt they are correct but it's not needed to fix this problem.
Do:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PREFIX/lib
export PATH=$PATH:$PREFIX/lib
Then finally you should be able to use GCC version 8.0.
~/gccbuild $ gcc-8 --version gcc-8 (GCC) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for
copying conditions. There is NO
warranty; not even for MERCHANTABILITY or F
FITNESS FOR A PARTICULAR PURPOSE.
Personally I'm trying to install it so that I can compile GCC 12, wish me luck with that lol.
I was preparing a demonstration of user mode Qemu's (qemu-user package) qemu-arm. To do so, I used a simple hello world C program hello.c:
#include <stdio.h>
int main()
{
printf("Oi, Qemu!\nPrograma C aqui!\n");
}
To cross compile it (statically linked), I used the cross toolchain from gcc-arm-linux-gnueabihf:
$ arm-linux-gnueabihf-gcc --version
arm-linux-gnueabihf-gcc (Ubuntu 9.3.0-10ubuntu1) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ arm-linux-gnueabihf-gcc hello.c -o hello_c_static -static
The output runs in both qemu-arm, Beaglebone Black AND ON THE PC.
How is it possible?!
EDIT
About the compiled executable:
file hello_c_static
hello_c_static: ELF 32-bit LSB executable, ARM, EABI5 version 1
(GNU/Linux), statically linked,
BuildID[sha1]=6a33aaa5abb9a14fbc0ca4f2e7b432d6fa5d7067, for GNU/Linux 3.2.0,
not stripped
Check ls -l /proc/sys/fs/binfmt_misc/ to see if your x86 system is set up to transparently run qemu on ARM binaries for you, the same way it can be to run WIINE on Windows executables or whatever using Linux binfmt_misc. https://en.wikipedia.org/wiki/Binfmt_misc
Admin guide https://www.kernel.org/doc/Documentation/admin-guide/binfmt-misc.rst
The installer for the qemu-user package might have registered the executable formats it supports.
With no binfmts registers, you'll just have the register and status "files". On my system, WINE and Mono boot scripts have registered handlers so I also see CLR and DOSWin files. e.g.
$ cat /proc/sys/fs/binfmt_misc/DOSWin
enabled
interpreter /usr/bin/wine
flags:
offset 0
magic 4d5a
If there's somehow a different mechanism, try using strace ./some_arm_program to see what system calls happen when you execute it.
Maybe also suspend it while it's running (control-z) and look at /proc/$(pidof some_arm_program)/maps and other files.
(This last section was written after the OP commented that they only saw register and status files, not qemu-arm, but they've since change their comment. It looks like binfmt-support is the answer.)
I am new to Cuda, and I am trying to compile this simple test_1.cu file:
#include <stdio.h>
__global__ void kernel(void)
{
}
int main (void)
{
kernel<<<1,1>>>();
printf( "Hello, World!\n");
return 0;
}
using this: nvcc test_1.cu
The output I get is:
In file included from /usr/local/cuda/bin/../include/cuda_runtime.h:59:0,
from <command-line>:0:
/usr/local/cuda/bin/../include/host_config.h:82:2: error: #error -- unsupported GNU version! gcc 4.5 and up are not supported!
my gcc --version:
gcc (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
How can I install a second version of gcc (4.4 -) along with 4.6 without messing everything up?
I found this old topic:
CUDA incompatible with my gcc version
the answer was:
gcc 4.5 and 4.6 are not supported with CUDA - code won't compile and
the rest of the toolchain, including cuda-gdb, won't work properly.
You cannot use them, and the restriction is non-negotiable.
Your only solution is to install a gcc 4.4 version as a second
compiler (most distributions will allow that). There is an option to
nvcc --compiler-bindir which can be used to point to an alternative
compiler. Create a local directory and the make symbolic links to the
supported gcc version executables. Pass that local directory to nvcc
via the --compiler-bindir option, and you should be able to compile
CUDA code without effecting the rest of your system.
But I have no idea how to do it
In my case I didn't have root rights, so I couldn't fully replace the current gcc (4.7) with the older version 4.4 (which I think would be a bad alternative). Although I did have rights where CUDA was installed. My solution was to create an extra folder (e.g. /somepath/gccfornvcc/), wherever I had rights, then to create a link to an nvcc accepted compiler. I already had gcc 4.4 available (but you can install it, without removing your current version).
ln -s [path to gcc 4.4]/gcc-4.4 /somepath/gccfornvcc/gcc
Then, in the same folder where the nvcc binary lives, you should find a file called nvcc.profile . There you just need to add the following line:
compiler-bindir = /somepath/gccfornvcc
And that will make nvcc use the proper compiler. This helps keeping the system in a proper state, keeping the newest compiler, but nvcc (only nvcc) will use the old compiler version.
Doing some research online shows several methods for accomplishing this task. I just tested the method found here: http://www.vectorfabrics.com/blog/item/cuda_4.0_on_ubuntu_11.04 and it worked like a charm for me. It steps you through installing gcc 4.4 and creating scripts to run that version with nvcc. If you prefer trying the method mentioned in your post I'd recommend following that first link to install gcc4.4 and then create symbolic links as mentioned in your post. Creating symbolic links in Linux is accomplished by using the 'ln' command.
For example:
ln -s [source file/folder path] [linkpath]
This link gives a few examples of creating symbolic links on both Ubuntu and Windows: http://www.howtogeek.com/howto/16226/complete-guide-to-symbolic-links-symlinks-on-windows-or-linux/. Hopefully that points you in the right direction.
I guess you may try the new, beta, version, that based on LLVM.
Another way to make nvcc work with non-default compiler (unlike #Sluml's answer, it allows more flexibility):
At first, just like #Slump proposed, you need to create directory ~/local/gcc-4.4/, and then create there symlinks for right versions of gcc: for i in gcc gxx; do ln -s /usr/bin/${i}-4.4 ~/local/cudagcc/${i}; done. Now when you run nvcc -ccbin ~/local/gcc-4.4/ ... nvcc will use correct versions of gcc.
Here is small CMake snippet of forcing nvcc use specific host compiler.
option (CUDA_ENFORCE_HOST_COMPILER "Force nvcc to use the same compiler used to compile .c(pp) files insted of gcc/g++" OFF)
if (${CUDA_ENFORCE_HOST_COMPILER})
set (CMAKE_GCC_TEMP_DIR "CMakeGCC")
file(MAKE_DIRECTORY ${CMAKE_GCC_TEMP_DIR})
execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_C_COMPILER} ${CMAKE_GCC_TEMP_DIR}/gcc)
execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CXX_COMPILER} ${CMAKE_GCC_TEMP_DIR}/g++)
set(CUDA_NVCC_FLAGS -ccbin ${CMAKE_GCC_TEMP_DIR} ${CUDA_NVCC_FLAGS})
endif()
Referenceļ¼
I update my gcc from 4.4 to 4.6. Then I could not use nvcc to compile my code. Luckily, by using the method provided by the following link. I set my default gcc compiler back to gcc 4.4. Now, I could compile file using either gcc4.4 or gcc4.6. quit cool
http://ubuntuguide.net/how-to-install-and-setup-gcc-4-1g4-1-in-ubuntu-10-0410-10
I am new to Cuda, and I am trying to compile this simple test_1.cu file:
#include <stdio.h>
__global__ void kernel(void)
{
}
int main (void)
{
kernel<<<1,1>>>();
printf( "Hello, World!\n");
return 0;
}
using this: nvcc test_1.cu
The output I get is:
In file included from /usr/local/cuda/bin/../include/cuda_runtime.h:59:0,
from <command-line>:0:
/usr/local/cuda/bin/../include/host_config.h:82:2: error: #error -- unsupported GNU version! gcc 4.5 and up are not supported!
my gcc --version:
gcc (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
How can I install a second version of gcc (4.4 -) along with 4.6 without messing everything up?
I found this old topic:
CUDA incompatible with my gcc version
the answer was:
gcc 4.5 and 4.6 are not supported with CUDA - code won't compile and
the rest of the toolchain, including cuda-gdb, won't work properly.
You cannot use them, and the restriction is non-negotiable.
Your only solution is to install a gcc 4.4 version as a second
compiler (most distributions will allow that). There is an option to
nvcc --compiler-bindir which can be used to point to an alternative
compiler. Create a local directory and the make symbolic links to the
supported gcc version executables. Pass that local directory to nvcc
via the --compiler-bindir option, and you should be able to compile
CUDA code without effecting the rest of your system.
But I have no idea how to do it
In my case I didn't have root rights, so I couldn't fully replace the current gcc (4.7) with the older version 4.4 (which I think would be a bad alternative). Although I did have rights where CUDA was installed. My solution was to create an extra folder (e.g. /somepath/gccfornvcc/), wherever I had rights, then to create a link to an nvcc accepted compiler. I already had gcc 4.4 available (but you can install it, without removing your current version).
ln -s [path to gcc 4.4]/gcc-4.4 /somepath/gccfornvcc/gcc
Then, in the same folder where the nvcc binary lives, you should find a file called nvcc.profile . There you just need to add the following line:
compiler-bindir = /somepath/gccfornvcc
And that will make nvcc use the proper compiler. This helps keeping the system in a proper state, keeping the newest compiler, but nvcc (only nvcc) will use the old compiler version.
Doing some research online shows several methods for accomplishing this task. I just tested the method found here: http://www.vectorfabrics.com/blog/item/cuda_4.0_on_ubuntu_11.04 and it worked like a charm for me. It steps you through installing gcc 4.4 and creating scripts to run that version with nvcc. If you prefer trying the method mentioned in your post I'd recommend following that first link to install gcc4.4 and then create symbolic links as mentioned in your post. Creating symbolic links in Linux is accomplished by using the 'ln' command.
For example:
ln -s [source file/folder path] [linkpath]
This link gives a few examples of creating symbolic links on both Ubuntu and Windows: http://www.howtogeek.com/howto/16226/complete-guide-to-symbolic-links-symlinks-on-windows-or-linux/. Hopefully that points you in the right direction.
I guess you may try the new, beta, version, that based on LLVM.
Another way to make nvcc work with non-default compiler (unlike #Sluml's answer, it allows more flexibility):
At first, just like #Slump proposed, you need to create directory ~/local/gcc-4.4/, and then create there symlinks for right versions of gcc: for i in gcc gxx; do ln -s /usr/bin/${i}-4.4 ~/local/cudagcc/${i}; done. Now when you run nvcc -ccbin ~/local/gcc-4.4/ ... nvcc will use correct versions of gcc.
Here is small CMake snippet of forcing nvcc use specific host compiler.
option (CUDA_ENFORCE_HOST_COMPILER "Force nvcc to use the same compiler used to compile .c(pp) files insted of gcc/g++" OFF)
if (${CUDA_ENFORCE_HOST_COMPILER})
set (CMAKE_GCC_TEMP_DIR "CMakeGCC")
file(MAKE_DIRECTORY ${CMAKE_GCC_TEMP_DIR})
execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_C_COMPILER} ${CMAKE_GCC_TEMP_DIR}/gcc)
execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CXX_COMPILER} ${CMAKE_GCC_TEMP_DIR}/g++)
set(CUDA_NVCC_FLAGS -ccbin ${CMAKE_GCC_TEMP_DIR} ${CUDA_NVCC_FLAGS})
endif()
Referenceļ¼
I update my gcc from 4.4 to 4.6. Then I could not use nvcc to compile my code. Luckily, by using the method provided by the following link. I set my default gcc compiler back to gcc 4.4. Now, I could compile file using either gcc4.4 or gcc4.6. quit cool
http://ubuntuguide.net/how-to-install-and-setup-gcc-4-1g4-1-in-ubuntu-10-0410-10
$ chmod +x libsomelibrary.so
$ ./libsomelibrary.so
Segmentation fault
$ gcc -O2 http://vi-server.org/vi/bin/rundll.c -ldl -o rundll
$ ./rundll ./libsomelibrary.so main
(application starts normally)
Why can't I just start libsomelibrary.so if it has usable entry point?
rundll.c is trivial:
void* d = dlopen(argv[1], RTLD_LAZY);
void* m = dlsym(d, argv[2]);
return ((int(*)(int,char**,char**))m)(argc-2, argv+2, envp);
Why is it not used internally when attempting to load a binary?
main is not the entry point recognised by the kernel or the dynamic linker - it is called by the startup code linked into your executable when you compile it (such startup code isn't linked into shared libraries by default).
The ELF header contains the start address.
Shared libraries are not designed to be directly runnable. They are designed to be linked into another codebase. It may have a usable entry point, but being executable entails more than merely having a usable entry point. The rundll utility is proof of this. Your second test shows that the shared library is indeed executable, but only after rundll does some work. If you are curious as to what all has to be done before the library code can be executed, take a look at the source code for rundll.
You can start shared libraries in Linux.
For example, if you start /lib/libc.so.6, it will print out its version number:
$ /lib/libc.so.6
GNU C Library stable release version 2.12, by Roland McGrath et al.
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.5.0 20100520 (prerelease).
Compiled on a Linux 2.6.34 system on 2010-05-29.
Available extensions:
crypt add-on version 2.1 by Michael Glad and others
GNU Libidn by Simon Josefsson
Native POSIX Threads Library by Ulrich Drepper et al
BIND-8.2.3-T5B
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.
There must be something missing from your library.