[coreboot] [RFC] Explicitly use C11

Julius Werner jwerner at chromium.org
Tue Nov 29 23:20:31 CET 2016

> A lot of the GNU extensions are used in our codebase, so if somebody
> feels strongly about moving away from GNU11 to C11, the code needs to
> be cleaned up. But that should be done in a different patch set.

I'd like to explicitly object to that. There are many GNU extensions
which are simply necessary to write sane, readable and performant code
(e.g. to implement non-double-evaluating MIN()/MAX() macros, to
cleanly control linking into particular sections, to get performant
code generated for IO accessor functions, etc.). The C standard by
itself is simply insufficient to support all systems programming use
cases, and if we forbade GNU extensions we'd have to rewrite
significant parts of coreboot in pure assembly and add weird, hardly
readable workarounds for many code patterns. I don't see how this
would be worth it just to try to get compatibility with compilers
nobody wants to use anyway, or for some theoretical goal of "standards
compliance" with no practical benefit. (Note that many GNU extensions
are implicitly available even without -std=gnuXX, some of them even if
you also enable -Werror=pedantic. But that doesn't not make them GNU
extensions, and there'd be no reason to treat them differently from
ones that require the -std flag. Ditching GNU extensions would mean
that every __attribute__, every __builtin and every extended asm
becomes illegal.)

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