GCC Runtime Library Exception in gcc/config/* files?

[Georg-Johann Lay]

Sebastian Huber schrieb:
> Hello,
> 
> there are some files in gcc/config/* that contain the GCC Runtime 
> Library Exception
> 
> grep -r --include='*.[ch]' 'GCC Runtime Library Exception' -l gcc/config 
> | wc
>     186     186    5361
> 
> and some files that don't include it
> 
> grep -r --include='*.[ch]' 'GCC Runtime Library Exception' -l gcc/config 
> -v | wc
>     753     753   20927
> 
> Does it matter? What should be used for new files?

Some machine headers are needed by libgcc.  Not all information is
available by means of built-in macros, so that compile-time decisions
in libgcc might need the target headers.

Likely, this dates back to the time when machine specific libgcc bits
where in gcc/config/$target.

Some users of (lib)gcc which compile their (proprietary) software
with gcc are paranoid about being infected by GPL due to using
libgcc which uses headers without runtime library exception.

https://gcc.gnu.org/ml/gcc-help/2012-08/msg00235.html

See also

https://gcc.gnu.org/PR61152

> libgcc sources are not yet separated completey from the compiler, i.e.
> it includes tm.h which in turn will include files from the compiler
> backend like arm.h.
> 
> As such files go into libgcc, they should contain the GCC Runtime
> Library Exception (RLE) in their license headers.
> 
> I know that these files actually don't add executable code to libgcc and
> that the FSF is fine without RLE in these files, yet there are potential
> users of GCC that are very concerned about linking their code against
> libgcc and about the non-RLE files that are part of the libgcc sources:
> as soon as a single file that goes into libgcc (e.g. by include) is GPL
> but does not contain the RLE, they won't use GCC as a whole.
> 
> Thus, adding RLE to these files can greatly increase acceptance of
> GCC/libgcc.


Johann