Re: [Patch] GCN: Fix --with-arch= handling in mkoffload [PR111966]

[Andrew Stubbs <ams@baylibre.com>]

On 03/04/2024 10:05, Tobias Burnus wrote:
> This patch handles --with-arch= in GCN's mkoffload.cc
> 
> While mkoffload mostly does not know this and passes it through to the 
> GCN lto1 compiler,
> it writes an .o file with debug information - and here the -march= in 
> the ELF flags must
> agree with the one in the other files. Hence, it uses now the 
> --with-arch= config argument.
> 
> Doing so, there is now a diagnostic if the -march= or --with-arch= is 
> unknown. While the
> latter should be rejected at GCC compile time, the latter was not 
> diagnosed in mkoffload
> but only later in GCN's compiler.
> 
> But as there is now a fatal_error in mkoffload, which comes before the 
> GCN-compiler call,
> the 'note:' which devices are available were lost. This has been 
> reinstated by using
> the multilib settings. (That's not identical to the compiler supported 
> flags the output
> is reasonable, arguable better or worse than lto1.)
> 
> Advantage: The output is less cluttered than a later fail.
> 
> To make mkoffload errors - and especially this one - more useful, it now 
> also initializes
> the colorization / bold.
> 
> OK for mainline?

OK. Thanks for fixing this.

Andrew

> 
> * * *
> 
> Example error:
> 
> gcn mkoffload: error: unrecognized argument in option '-march=gfx1111'
> gcn mkoffload: note: valid arguments to '-march=' are: gfx906, gfx908, 
> gfx90a, gfx1030, gfx1036, gfx1100, gfx1103
> 
> where on my TERM=xterm-256color,  'gcn mkoffload:' and the quoted texts 
> are in bold,
> 'error:' is red and 'note:' is cyan.
> 
> Compared to cc1, the 'note:' lacks 'fiji', the list is separated by ', '
> instead of ' ', and cc1 has a "; did you mean 'gfx1100'?".
> And the program name is 'gcn mkoffload' instead of 'cc1'.
> 
> Tobias
> 
> PS: The generated multilib list could be later changed to be based on 
> the gcn-.def file;
> or we just keep the multiconfig variant of this patch.

I think a .def file would be more future-proof if we ever have multilibs 
for options other than -march, but this works for now.

Andrew