Toolchain to crosscompile Applications for BBB - linux

My native machine is ubuntu based 14.04 LTS x86_64 system, I want to cross-compile applications and QT programs for Beaglebone black, which is an armv7 based system running on Debian 2015 distribution.
Which toolchain I should install on my native system, to get this done?

Here is a very usefull link how to set up the crosscompiler, uboot, kernel and the filesystem for a beaglebone black.
If you only want to crosscompiler, then just follow the few code lines in the Crosscompiler chapter
https://eewiki.net/display/linuxonarm/BeagleBone+Black

To cross-compile applications you need to use the ' arm-linux-gnueabihf ' compiler in the Ubuntu. Ubuntu 14.04 LTS was released with gcc-4.8.2. It is really important that the version of this GCC compiler matches the version deployed on the beaglebone black image. The reason for this is that different compilers have different libc versions, and version mismatching causes linker errors that are very tricky to solve.
You can try running,
gcc --version
on both your native Ubuntu system and the Beaglebone Black and see if the gcc version matches. If yes, you are good to go. Otherwise, install the appropriate toolchains.

Related

glibc version for aarch64

I'm cross-compiling an application for aarch64 on my x86 Ubuntu Bionic system, and I have problems with glibc version mismatch. My cross-compile toolchain was using v2.27, while the system that is to run the application has v2.24. I thought that it might be due to my toolchain having a too high version, so I decided to downgrade.
After removing all previous cross-compilation installs, I installed gcc-4.8-aarch64-linux-gnu (as I had successfully cross-compiled the application with this version on a different host system), thinking that it would install an older aarch64 version of glibc to /usr/aarch64-linux-gnu/lib/. However, again, v2.27 was installed (I verified that this directory didn't exist before installing the new cross-compilation toolchain).
So my question is twofold:
What determines which aarch64 version of glibc is installed on my system when installing gcc-4.8-aarch64-linux-gnu? Is it directly tied to my own system's x86 version of glibc?
Is there a correct way to install the aarch64 version of glibc v2.24 (or lower) on my system?
I concur with your hypothesis. After battling similar symptoms for 40 hours straight, I've discovered this confirmation:
https://packages.ubuntu.com/impish/gcc-10-aarch64-linux-gnu
https://packages.debian.org/bullseye/gcc-aarch64-linux-gnu
Note that Ubuntu 21.10 (Impish) and Debian 11 (Bullseye) have packages for a gcc 10 cross compiler. Be wary of the very confusing fact the Ubuntu's default package is actually gcc 11, but Debian 11's default is gcc 10. The similar version numbers of Debian and gcc are a coincidence. Also ignore for now the fact that Ubuntu's package is gcc 10.3.0 and Debian's is gcc 10.2.1.
Focus instead on the recommendations and dependencies of each package. Ultimately the Ubuntu package calls up libc >= 2.34, while the Debian package calls up libc >= 2.28.
Sure enough, when I cross-compile from Impish on x86 for Bullseye on aarch64 (despite having a complete SYSROOT for the target), I get this at runtime:
/lib/aarch64-linux-gnu/libc.so.6: version 'GLIBC_2.34' not found
But your question remains, is there any tie between the host libc and that used by the cross-compiler? The answer is a definite maybe.
See this excellent answer and links for an overview of a cross-compiler. The take-away:
You don't just cross-compile glibc, you need to cross-compile an entire toolchain. Toolchain components are ALWAYS: ld + gcc + libc + gdb.
So the C library is an integral part of the cross-compiler.
What shenanigans then, are going on when you install gcc-aarch64-linux-gnu? It's just a compiler - only one of the four parts of a toolchain.
Well apparently there's some flexibility. Technically, a cross-compiler can be naked. That's typically only useful when you're compiling an operating system, rather than an executable that runs on an operating system. So you can construct special toolchains for special purposes.
But for the standard purpose (cross compiling for Linux on another architecture) you want a typical toolchain. Which is where the package's dependencies and recommendations come in. A gcc is always in want of an ld which is always in want of a libc, and the ménage à trois is intimate. In fact, gcc is built with libc using ld in a complex do-si-do. See this example from a great guide by Preshing on Programming:
It's possible to force separation and link to other libraries, but it's not easy.
For example, the linker you use has a set of default search directories that are baked in. From the fine manual:
The default set of paths searched (without being specified with -L) depends on which emulation mode ld is using, and in some cases also on how it was configured.
And it gets more intwined. By default, gcc will call on a dynamic linker whose location is hard-coded. For a cross-compiler, it might be something like /lib/ld-linux-aarch64.so.1. Not only that, the executable may also end up with the hardcoded path, as its program interpreter.
Again, if you're careful you can tear apart the toolchain and override things. But not only is it tricky to enforce, particularly if you have a complex build, the multitude of combinations of options and paths means there are also often bugs. So your host environment can easily leak into your cross-compiling toolchain.
So in summary, cross-compiling requires a toolchain. While pulling a cross-compiler from a package manager seems like an easy and legitimate thing to do, it comes with a lot of implicit baggage. You can either carefully follow the package dependencies to check what version you're getting, or use one of the many dedicated toolchain environments, such as crosstool-NG.

Why does Ubuntu install ARM64 compilers with a version suffix that breaks autoconf?

I just installed the ARM64 cross-complier (aarch64-linux-gnu) on x86_64 Ubuntu 16.04 and all of the binaries have "-4.8" (like aarch64-linux-gnu-gcc-4.8). When I try to configure with --host=aarch64-linux-gnu, it fails to find aarch64-linux-gnu-gcc and falls back to the native gcc.
What did I miss? Is there an additional package that needs installation other than gcc-4.8-aarch64-linux-gnu? Or is there another mystery parameter to autogen.sh/configure that I don't know about?
Thanks.

Install a GCC ARM Embedded toolchain

I would like to load a very simple, hello world program, on an Embedded ARM processor. For this, I would like to install a toolchain in order to cross compile my code. I am currently working on a 64-bit Linux OS. Does anyone know of a GCC ARM embedded toolchain that I can download? I've downloaded a pre-built version of Linaro GCC but it only runs on a 32-bit Linux machine and I can't install the ia32-libs package because my Linux machine has no internet connection.
The gcc-arm toolchain I'm using for ARM Cortex-M processors can be found here-
https://launchpad.net/gcc-arm-embedded
It also builds for Cortex-A targets, which should cover the majority of embedded ARM systems.
You can download standalone distributions for many operating systems, including linux.
There are also 64bit builds of Linaro toolchain here. Just download the x86_64 and not the i686 version.

Installing gcc on linux without c compiler

How can I install gcc on a system that have not any c compiler?
this system is a linux base firewall and have not any c compiler.
I guess you a have an appliance running Linux and shell-access, but neither a package manager nor a compiler is installed.
So, you need to cross-compile gcc and the whole toolchain (at least binutils) - this is quite simple, because the ./configure scripts of gcc, binutils, gdb etc. support cross-compiling with the --target= option. So all you have to do is to find out the target architecure (uname helps) and then download, unpack the gcc sources on a linux-host and run ./configure --target=$YOUR_TARGET.
With this, you now can build a cross-compiler gcc - this still runs on your host, but produces binaries for your target (firewall appliances).
This may already be sufficient for you, a typical desktop PC is much faster than a typical appliance, so it may make sense to compile everything you need on the Desktop PC with the cross-compiler and cross-binutils.
But if you really wish to do so, you can now also use your cross-compiler to compile a gcc running on your target (set this as --host= option) and compiling for your target (set this as --target option).
You can find details about allowed host/targets and examples in the gcc documentation: http://gcc.gnu.org/install/specific.html.
It depends on the distribution, if it's based on debian or some other of the big ones you can install gcc through apt-get or similar tool.
If it's a more basic system you need to compile gcc yourself on another computer and copy it over. It will be easiest if you have another computer with the same architecture (i386, arm or x86_64 for example).
I think that you might want to compile it statically also, so that you don't have dependencies on external libraries.
How do you plan to get all the source code needed for GCC loaded onto your machine? Could you mount the ISO image onto this machine and install from there?
Since you are using Endian Firewall, see "Building a development box" at the following link:
http://alumnus.caltech.edu/~igormt/endian/tips.html
If it's a debian based distribution, you can use
sudo apt-get install gcc
Note: maybe you must change "gcc" by a specific version of the debian package.

Which cross compiler?

What is the difference between
MinGW cross compiler and
GCC Cross compiler.
Which one used in which operating system?
I need to create an EXE file in the Linux operating system using Qt, hence which is the cross compiler to be used?
MinGW is a GCC cross compiler for Windows environments. (There are multiple GCC cross compilers for various different targets.)
To compile Windows executables on your Linux box, you want a MinGW install for your distribution of Linux.
If you're running
Debian, you want http://packages.debian.org/lenny/mingw32 (apt-get install mingw32)
Ubuntu, you want http://packages.ubuntu.com/jaunty/mingw32 (apt-get install mingw32)
Red Hat Linux or CentOS, you want several of the MinGW packages from http://download.fedora.redhat.com/pub/epel/5/i386/repoview/M.group.html (see EPEL how-to then yum install mingw32-binutils and mingw32-gcc-g++ at minimum)
Gentoo, see http://www.gentoo-wiki.info/MinGW
openSUSE, then you can find builds at http://download.opensuse.org/repositories/CrossToolchain:/mingw/
MingW32 is a port of GCC with "win32 target".
There are two architecture in a cross-compiler: host and target. The host is the platform the compiler run on; the target is what the result code will run.
Assume you are using Ubuntu, you can see the package here.
MinGW is basically a port of GCC and related tools, allowing them to run natively on Windows machines.
Cross compiling is the act of using a compiler on one operating system/architecture to generate a binary/EXE/DLL/object that is compatible with another operating system/architecture. Basically, you ask the compiler to generate assembly and startup routines for something other than the host OS's default.
If you were on a Linux machine, you'd use GCC to compile it for the Linux machine... If you were on a Windows machine, you'd use MinGW, but with flags to tell it to compile for the Linux machine's specifications.
GCC is usually used in Linux.. MinGW is just a Windows port of GCC to compile source to EXE files.

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