Re: [Xen-devel] [RFC 6/7] arm: Introduce dummy empty functions for data only C files

[Julien Grall <julien.grall.oss@xxxxxxxxx>]

On Tue, 12 Nov 2019, 05:57 Stefano Stabellini, <sstabellini@xxxxxxxxxx> wrote:

On Wed, 6 Nov 2019, Andrii Anisov wrote:
> From: Andrii Anisov <andrii_anisov@xxxxxxxx>
>
> ARM Compiler 6 has a proven bug: it compiles data only C files with
> SoftVFP attributes. This leads to a failed linkage afterwards with
> an error:
>
> Error: L6242E: Cannot link object built_in.o as its attributes are incompatible with the image attributes.
> ... A64 clashes with SoftVFP.
>
> The known workaround is introducing some code into the affected file,
> e.g. an empty (non-static) function is enough.

Oh man, this is truly horrible.

If we really have to do this please:

- use the same dummy function name in all files
- the function should be static
- hiding the function within a #ifdef ARMCC block
- potentially hide the whole horrible hack behind a #define so that it
  would become at the call site:

 +ARMCC_DUMMY_FUNC_HACK()

The risk here is we may introduce new file in the future possibly in common code with similar issues. So I would prefer if we can find an automatic way to do this. Some ideas:

    - Add the function at compile time (via makefile). This would be done for all the files but that's should not be a major issues.

    - Force disable softfvp either via command line, new line in the code or rewriting the attribute of the object.

But before spending time trying to workaround a buggy compiler. What's the plan with it? Is it going to be used in production or just a demo?

Cheers,

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel