RE: ERROR: already selected `xxxx' processor

["Dave Korn" <dave dot korn at artimi dot com>]

On 05 July 2006 17:00, Thomas Fleischmann wrote:

> Whilst the gcc doesn't support our used cpu MCF5213 100%, we use the
> compilerswitch -m5200 to generate generic code for a MCF52xx. 
> We also need to use inline assembly for the MCF5213 stuff (movec ...,
> %rambar). So we have to apply a second compiler switch to be passed to gas
> -Wa,-m5213 (-Wa,-mcpu=5213 for binutils 2.17).  
> 
> This is ok for binutils 2.16.1 but not for 2.17.
> 
> As the compiler passes two "cpu" selections to gas, one indirectly
> generated by gcc's -m5200 and one direktly passed by -Wa,-mcpu=5213, gas is
> "confused".  
> File gas/config/tc-m68k.c checks this and produces an error, because of two
> different selected cpu's. 
> 
> My suggestion is:
> If gas is invoked with -mcpu=xxx, this should override the former settings.
> Additional a warning will be produced. 
> 
> My included patch would produce this behavior.
> Please could you check if I done everything right and if it is worth to be
> applied to gas. 


  You mean, let's patch gas to accept invalid command lines rather than you
fix your invalid kludgey hacked-up build environment?  I suggest let's not!  I
appreciate that you have a valid motive here owing to the disjunction between
what cpus gcc understands and what cpus gas understands, but this surely isn't
the way to resolve it.  The fact that it used to be accepted in 2.16.1 and now
there's a check for it and it is specifically disallowed suggests that there
may be some kind of problem.  Did you check the archives to see why this test
was added?

  The correct fix for this situation would be to add a -m5213 option to gcc,
not to try and persuade gas to accept two or more --cpu options at the same
time.  It could be as simple as using the driver specs so that -m5213 gets
turned into -m5200 when it's passed to cc1 in the CC1_SPEC and gets turned
into -mcpu=5213 when it's passed to gas in the ASM_SPEC.  Wouldn't that do
everything you need, and be a somewhat cleaner solution as well?

    cheers,
      DaveK
-- 
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