Re: [PATCH] adjust warning_n() to take uhwi (PR 84207)

[Manuel López-Ibáñez <lopezibanez at gmail dot com>]

On 13/02/18 03:10, Martin Sebor wrote:
> PS Is there any reason why diagnostic-core.h and diagnostic.c
> does not/should not include tree.h and other GCC headers?

The short reason is that we want to keep the core diagnostics as independent of 
the rest of the compiler as possible so that using it doesn't bring undesired 
dependencies. It took some effort a few years ago to clean-up headers, in 
particular, the mess of toplev.h, inclusion of rtl in FE files, inclusion of 
tree.h in back-end files, etc. I'm not sure what is the status now but I'm 
afraid that without any definition of actual internal/external interfaces and 
without actual physical separation of files and compilation steps (read: 
libraries), the headers may have crept back in.

Long time ago there was a plan of making GCC more modular, perhaps moving to a 
library framework like LLVM/Clang. I even had a patch that moved all core 
diagnostics and line-map stuff to its own libdiagnostic that was used by libcpp 
and the rest of the compiler (instead of overriding call-backs in libcpp like 
we do now and forcing libcpp into every executable that wishes to use 
diagnostics or line-maps). Unfortunately, it never worked properly because of 
the build machinery.

More background (probably very much outdated and forgotten):

https://docs.google.com/document/pub?id=1ZfyfkB62EFaR4_g4JKm4--guz3vxm9pciOBziMHTnK4

https://gcc.gnu.org/wiki/rearch

https://gcc.gnu.org/wiki/ModularGCC

Cheers,

Manuel.