// -*- mode:doc; -*- // vim: set syntax=asciidoc: [[toolchain]] Cross-compilation toolchain --------------------------- A compilation toolchain is the set of tools that allows you to compile code for your system. It consists of a compiler (in our case, +gcc+), binary utils like assembler and linker (in our case, +binutils+) and a C standard library (either http://www.gnu.org/software/libc/libc.html[GNU Libc], http://www.uclibc.org/[uClibc] or http://www.musl-libc.org/[musl]). The system installed on your development station certainly already has a compilation toolchain that you can use to compile an application that runs on your system. If you're using a PC, your compilation toolchain runs on an x86 processor and generates code for an x86 processor. Under most Linux systems, the compilation toolchain uses the GNU libc (glibc) as the C standard library. This compilation toolchain is called the "host compilation toolchain". The machine on which it is running, and on which you're working, is called the "host system" footnote:[This terminology differs from what is used by GNU configure, where the host is the machine on which the application will run (which is usually the same as target)]. The compilation toolchain is provided by your distribution, and OpenADK has nothing to do with it (other than using it to build a cross-compilation toolchain and other tools that are run on the development host). As said above, the compilation toolchain that comes with your system runs on and generates code for the processor in your host system. As your embedded system has a different processor, you need a cross-compilation toolchain - a compilation toolchain that runs on your _host system_ but generates code for your _target system_ (and target processor). For example, if your host system uses x86 and your target system uses ARM, the regular compilation toolchain on your host runs on x86 and generates code for x86, while the cross-compilation toolchain runs on x86 and generates code for ARM. OpenADK provides only one solution for the cross-compilation toolchain. The versions for binutils, gcc, gdb and libc are fixed. It is a combination of mostly the latest versions, which are known to work in this combination and are known to produce usable firmware images. You normally do not need to know the deep details, it is part of OpenADK policy to keep this part simple for the user. You can only choose between three C libraries: http://www.uclibc.org[uClibc], the http://www.gnu.org/software/libc/libc.html[glibc] and http://www.musl-libc.org[musl]. There are some minimal configuration options provided in +Toolchain settings+. You can enable or disable the building of following components and toolchain options: * GDB (enabled by default) * GNU C++ compiler (enabled by default, when disabled will prevent some packages to show up in the menu selection) * Stack Smashing Support (SSP) support for GNU C/C++ Compiler (experimental, some packages will fail to build) * Link Time Optimization (LTO) support for GNU C/C++ Compiler (experimental, some packages will fail to build)