TBB cross compilation journey

Environment and tools

• TBB compilation environment:Ubuntu18.04
• TBB version: oneTBB-2019_U8
• Cross compilation tool chain: gcc-linaro-6.2.1-2016.11-x86_64_aarch64-linux-gnu
• Test project construction environment: Windows7+ 交叉编译工具链+Qt5.9.3
• Operating environment: Xilinx Zynq UltraScale+ MPSoC+Ubuntu

Compile

For cross-compiling tool chain, please download the configuration yourself.

Before performing the following steps, please ensure that the following commands can view the version of the compilation chain, which means that the compilation chain configuration is successful:

aarch64-linux-gnu-gcc -v

aarch64-linux-gnu-g++ -v

TBBProvided to us makefile, if it is compiled in the target environment, it will detect the environment based on the script interaction, and then automatically configure the compilation parameter rules according to the environment, which is very Reassuring.

If it is cross-compilation, there is actually no trouble as imagined...

Note : do not need to fully understand tbbthe compiler parameters and rules, and how to automatically depending on the environment the right compiler, and then rewrite it makefile, it will be a hard thing not to please, especially for makefile初学者it.

We can achieve cross-compilation through the following instructions:

make CC=aarch64-linux-gnu-gcc CXX=aarch64-linux-gnu-g++

Q&A

-m64 parameter

The first encounter is a cross-compiler tool chain aarch64-linux-gnu-g++absent -m64parameters

In my environment, which is in part oneTBB-2019_U8/build/linux.gcc.inc, simply do the following changes; of course, and I related to the environment, here are for reference only:

ifeq (intel64,$(arch))
#    ITT_NOTIFY = -DDO_ITT_NOTIFY
#    CPLUS_FLAGS += -m64 $(RTM_KEY)
    CPLUS_FLAGS += $(RTM_KEY)
#    LIB_LINK_FLAGS += -m64
endif

xxxx.so.x not found

Through sudo find / -name xxxx.so*search, we found xxxx.sopresent in the cross-compiler tool chain, then we "copy" a path to the destination can be renamed.

It is worth note that if a direct copy and rename:

cp xxxxx.so xxxxx.so.x

Then there will only be problems in the compilation process Too many open files

The correct approach should be to establish a soft link:

ln -s  xxxxx.so xxxxx.so.x

ld-linux-aarch64.so.1 not found

Not found in the cross compilation chain ld-linux-aarch64.so

But it is actually in the cross compilation tool chain ld.so

The specific path is:
gcc-linaro-6.2.1-2016.11-x86_64_aarch64-linux-gnu/aarch64-linux-gnu/libc/lib/ld-2.23.so

In the same way, just create a soft link.

Then compile successfully~~

But it’s still too early...

undefined reference to “__dlsym”

When writing the test demo, it was found that the compilation failed because of:

undefined reference to "__dlsym"
undefined reference to "__dlopen"

Use nm -D libtbb.so.2to view libtbb.so.2library content, the existence of an externally defined or undefined __dlsymsuch as:

So where are these functions defined?

Nor found in the associated header file __dlsymdefinition, only to find dlsymand so on.

In the end, I couldn’t find it... So I went to compare the ones lbbtbb.so.2that can be used normally, and I found that they don’t have this stuff at all!

Then the problem lies in compiling the dynamic library, am I going to do it again?

Using ‘dlopen’ in statically linked applications requires at runtime the shared libraries from the glibc version used for linking

Then I noticed the warning seen in the title, so I linux.gcc.incmake the following changes in

# PIC_KEY选项加上-ldl
PIC_KEY = -fPIC -ldl
# LIBDL不需要了，注释掉
# LIBDL = -ldl

Again using compiled nm -D libtbb.so.2to view the contents of a dynamic library

test

Qt Demo

Please refer to the environment Daheng Zhixing Pallas_Qt_mingw32_SDK development environment to build

pro

INCLUDEPATH += xxx\tbb\include
DEPENDPATH += xxx\tbb/lib
LIBS += -Lxxx\tbb/lib \
        -ltbb -ltbbmalloc -ltbbmalloc_proxy -ldl

main

As used herein, parallel_forverify dynamic library is available, is a very simple example.

#include <QCoreApplication>
#include <iostream>
#include <tbb/tbb.h>

using namespace tbb;
using namespace std;

int main(int argc, char *argv[])
{
    
    
    QCoreApplication a(argc, argv);

    tbb::parallel_for(1, 10, [](int i){
    
    std::cout << i << std::endl; });

    return a.exec();
}

Target environment test

Grant permissions

chmod 777 daheng_tbb_test

carried out

./daheng_tbb_test

Q&A

The following problems occurred during execution:

error while loading shared libraries: libXXX.so.X: cannot open shared object file: No such file

The reason for the above problem is that we cannot be found in the target environment. tbb库The method I use is:

• Put our library in a certain path, for example /usr/loca/lib

• And then modify ld.so.confthat the implementation vi /etc/ld.so.confwill be included into our path

• Update, execute ldconfig

Then run it again:

End

It's finally over!