Building uclibc for big-endian and little-endian target.

[Sedat Dilek]

On Wed, Oct 16, 2013 at 9:04 AM, Mike Frysinger <vapier at gentoo.org> wrote:
> On Tuesday 15 October 2013 15:00:40 Khem Raj wrote:
>> On Oct 15, 2013, at 10:30 AM, Steve Ellcey wrote:
>> > I have a question about endiness and uclibc.  I am trying to build
>> > multiple versions of uclibc for MIPS, including big and little endian
>> > versions.  What I notice is that in Rules.mak there are lines:
>> >
>> > CPU_LDFLAGS-$(ARCH_LITTLE_ENDIAN) += -Wl,-EL
>> > CPU_LDFLAGS-$(ARCH_BIG_ENDIAN)    += -Wl,-EB
>> >
>> > to add -EL or -EB to linker commands (this seems to be generic for all
>> > architectures).
>> >
>> > What I do not see is any generic (or MIPS specific) code to add -EL or
>> > -EB to CPU_CFLAGS (or CPU_FLAGS-y to be exact).  I am wondering if there
>> > is a specific reason for this?  Right now the uclibc build seems to
>> > assume that the compiler I am using to build uclibc will always generate
>> > the correct endiness without any flags.
>>
>> That was consensus we had some time ago. Otherwise these flags were getting
>> too many and difficult to deal with.
>
> well, i think that was more focused on cpu/arch/tune flags.  we still have
> endian flags in there for various targets.  adding the right logic for mips
> would be OK imo.

As the Freetz router project had to deal with BE/LE issues, we (yes, I
was more active these days) decided to define the Kconfig logic in:

     extra/Configs/Config.mips

...and added the the CPU_FLAGS-* (CPU optimization etc.) stuff to...

     Rules.mak

Please see the patch in [1] for more details.

- Sedat -

[1] http://freetz.org/browser/trunk/toolchain/make/target/uclibc/0.9.33.2/100-fritzbox_specific_arch_flags.freetz.patch