Re: [PATCH 2/2] libdiagnostics: work-in-progress implementation

[David Malcolm <dmalcolm@redhat.com>]

On Tue, 2023-11-07 at 08:54 +0100, Simon Sobisch wrote:
> Thank you for our work and providing this patch.
> 
> GCC related questions:
> 
> Is it planned to change GCC diagnostics to use libdiagnostic itself?

No.  GCC uses C++ internally, and the internal diagnostic API is
written in C++. libdiagnostic wraps up this C++ API in a C interface. 
GCC would continue using the C++ interface internally.

> 
> Is it planned to "directly" add features or would the result for GCC
> be 
> identical (apart from build changes)?
> 
> So far it looks like it wouldn't be possible to "just build 
> libdiagnostics", and much less to "just distrubute its source" for
> that 
> purpose, is it?

Correct: libdiagnostics is just an extra .cc file within the rest of
GCC, and almost all the work is being done in other .cc files.

> As building GCC does take a significant amount of resources and 
> system-wide switching to a new GCC version is considered a serious
> task 
> (distributions commonly stay with their major GCC version for quite
> some 
> time), I'd search for an option to building a "self-contained"
> version 
> that does not need the complete necessary toolset and may also be 
> distributed separately.

It's possible to reduce the resources by disabling bootstrapping, and
only enabling a minimal set of languages.

I'd see libdiagnostics as coming from the distribution build of GCC.  I
suppose distributions might want to have a simple build of GCC and ship
just the .so/.h file from libdiagnostics from the build.

> 
> This definitely can come later, too; I _guess_ this would mean moving
> part of GCCs code in a sub-folder libdiagnostics and use it as 
> subproject for configure/make, with then option to run "make dist" in
> that subfolder alone, too.

It would involve a lot of refactoring :)

> 
> The main reason for that would be to allow applications move from
> their 
> previous own diagnostic to libdiagnostics, if it isn't available on
> the 
> system they can build and install it as subproject, too; and to be
> able 
> to build libdiagnostics with a much reduced dependency list.

I can try to come up with a minimal recipe for building gcc if all you
want is libdiagnostics

> 
> 
> Thank you for considering that,
> Simon

Thanks
Dave

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