[U-Boot] [U-Boot,12/12] lib: Enable private libgcc by default

[Simon Glass]

On 4 June 2016 at 02:00, Tom Rini <trini at konsulko.com> wrote:
> On Thu, May 26, 2016 at 06:01:47PM +0200, Marek Vasut wrote:
>
>> This patch decouples U-Boot binary from the toolchain on systems where
>> private libgcc is available. Instead of pulling in functions provided
>> by the libgcc from the toolchain, U-Boot will use it's own set of libgcc
>> functions. These functions are usually imported from Linux kernel, which
>> also uses it's own libgcc functions instead of the ones provided by the
>> toolchain.
>>
>> This patch solves a rather common problem. The toolchain can usually
>> generate code for many variants of target architecture and often even
>> different endianness. The libgcc on the other hand is usually compiled
>> for one particular configuration and the functions provided by it may
>> or may not be suited for use in U-Boot. This can manifest in two ways,
>> either the U-Boot fails to compile altogether and linker will complain
>> or, in the much worse case, the resulting U-Boot will build, but will
>> misbehave in very subtle and hard to debug ways.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> Cc: Albert Aribaud <albert.u.boot at aribaud.net>
>> Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
>> Cc: Simon Glass <sjg at chromium.org>
>> Cc: Tom Rini <trini at konsulko.com>
>> Reviewed-by: Tom Rini <trini at konsulko.com>
>
> Applied to u-boot/master, thanks!
>
> And since this change was contentious when previously proposed, I'm
> going to explain why I'm taking this now.  There are a number of
> correctly configured toolchains out there today that fail to build
> U-Boot on some platforms.  This is because we're giving the compiler
> conflicting requests (build soft-float! use whatever libgcc you have!).
> The era of multilib toolchains being prevalent (at least for 32bit ARM)
> is long over.  The right thing to have done, always, would be to provide
> the required functions ourselves so that we are in control.  So, thanks
> again Marek for following up on the series as I had asked you to, this
> fixes build failures for me on about a dozen platforms.

Thank you Marek!

- Simon