Compiler support or helper functions specific to the compilation tools are typically used when the compiler cannot easily produce a suitable code sequence itself.
In RVCT v4.0 and later, the helper functions are generated by the compiler in the resulting object files.
In RVCT v3.1 and earlier, the helper functions reside in libraries. Because these libraries are specific to the ARM C compiler, they are intended to be redistributed as necessary with your own code. For example, if you are distributing a library to a third party, they might also require the appropriate helper library to link their final application successfully. Be aware of redistribution rights of the libraries, as specified in your End User License Agreement.