• Wolfgang Denk's avatar
    ARM: compiler options cleanup - improve tool chain support · f772acf8
    Wolfgang Denk authored
    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 kernel 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: default avatarWolfgang Denk <wd@denx.de>
    Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
    Cc: Dirk Behme <dirk.behme@googlemail.com>
    Cc: Magnus Lilja <lilja.magnus@gmail.com>
    Cc: Tom Rix <Tom.Rix@windriver.com>
    Cc: Prafulla Wadaskar <prafulla@marvell.com>
    Acked-by: default avatarSergey Kubushyn <ksi@koi8.net>
    Tested-by: default avatarMagnus Lilja <lilja.magnus@gmail.com>
    Tested-by: default avatarAndrzej Wolski <awolski@poczta.fm>
    Tested-by: default avatarGaye Abdoulaye Walsimou <walsimou@walsimou.com>
    Tested-by: default avatarTom Rix <Tom.Rix@windriver.com>
    Tested-by: default avatarJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
    f772acf8
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