[U-Boot] [PATCH] ARM: compiler options cleanup - improve tool chain support
Magnus Lilja
lilja.magnus at gmail.com
Mon Aug 17 22:17:57 CEST 2009
Hi Wolfgang,
2009/8/17 Wolfgang Denk <wd at denx.de>:
> For some time there have been repeated reports about build problems
> with some ARM (cross) tool chains. Especially issues about
> (in)compatibility with the tool chain provided runtime support
> library libgcc.a caused to add and support a private implementation
> of such runtime support code in U-Boot. A closer look at the code
> indicated that some of these issues are actually home-made. This
> patch attempts to clean up some of the most obvious problems and make
> building of U-Boot with different tool chains easier:
>
> - Even though all ARM systems basicy used the same compiler options
> to select a specific ABI from the tool chain, the code for this was
> distributed over all cpu/*/config.mk files. We move this one level
> up into lib_arm/config.mk instead.
>
> - So far, we only checked if "-mapcs-32" was supported by the tool
> chain; if yes, this was used, if not, "-mabi=apcs-gnu" was
> selected, no matter if the tool chain actually understood this
> option. There was no support for EABI conformant tool chains.
> This patch implements the following logic:
>
> 1) If the tool chain supports
> "-mabi=aapcs-linux -mno-thumb-interwork"
> we use these options (EABI conformant tool chain).
> 2) Otherwise, we check first if
> "-mapcs-32"
> is supported, and then check for
> "-mabi=apcs-gnu"
> If one test succeeds, we use the first found option.
> 3) In case 2), we also test if "-mno-thumb-interwork", and use
> this if the test succeeds. [For "-mabi=aapcs-linux" we set
> "-mno-thumb-interwork" mandatorily.]
>
> This way we use a similar logic for the compile options as the
> Linux kenrel does.
"kenrel" => "kernel" :-)
>
> - Some EABI conformant tool chains cause external references to
> utility functions like raise(); such functions are provided in the
> new file lib_arm/eabi_compat.c
>
> Note that lib_arm/config.mk gets parsed several times, so we must
> make sure to add eabi_compat.o only once to the linker list.
>
> Signed-off-by: Wolfgang Denk <wd at denx.de>
> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> Cc: Dirk Behme <dirk.behme at googlemail.com>
> Cc: Magnus Lilja <lilja.magnus at gmail.com>
> Cc: Tom Rix <Tom.Rix at windriver.com>
> Cc: Prafulla Wadaskar <prafulla at marvell.com>
> ---
>
> I have run a full "MAKEALL arm" for ELDK releases 3.1 (gcc 3.3.3),
> 3.1.1 (gcc 3.3.3), 4.1 (gcc 4.0.0) and 4.2 (gcc 4.2.2, both as "arm"
> [softfloat] and "armVFP" [VFP hardfloat]), and all of these both with
> USE_PRIVATE_LIBGCC=yes (i. e. using U-Boot internal libgcc
> replacement code) and without (i. e. using the tool chain provided
> standard libgcc instead).
>
> The ELDK fails to build the big-endian IXP boards, but this is a
> restriction of the ELDK, not a new issue introcued by this patch.
> Except of this, all build were succesful.
>
> Note 1: Please note that older tool chains (based on binutils versions
> older than 2.16) will have problems with the SORT_BY_ALIGNMENT()
> and SORT_BY_NAME() functions introduced to the linker scripts with
> commit f62fb99941c6. I'll soon submit a patch to fix this issue. Final
> tests are running right now.
>
> Note 2: Even though this is a bigger change, I consider it a bug fix
> and therefor tend to have it included into the upcoming release. Of
> course this requires sufficient test coverage and feedback. Please
> help!!
I've done compile time testing for the ARM11 boards using a gcc 4.1.2
toolchain that I often use and also Codesourcery's 2009-q1 (gcc 4.3.3)
(both with and without USE_PRIVATE_LIBGCC=yes), everything compiles
fine.
I hope to be able to do some run-time testing of some i.MX31 U-boot
binaries later this week, so far I haven't tried them at all.
Regards, Magnus
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