[U-Boot] [PATCH] ARM: compiler options cleanup - improve tool chain support

[ksi at koi8.net]

On Mon, 17 Aug 2009, Wolfgang Denk wrote:

Ack-by: Sergey Kubushyn <ksi at koi8.net>
---

> 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.
> 
> - 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>
> ---

---
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