Re: RFC: Mips option parsing patch

[Thiemo Seufer <ica2_ts at csv dot ica dot uni-stuttgart dot de>]

Daniel Jacobowitz wrote:
[snip]
> Binaries built with -march=r8000 -mips2 are now marked:
>   Flags:                             0x30000100, mips4 UNKNOWN
> 
> The mips4 marking is wrong, but that's a BFD bug - it sets mips_arch
> unconditionally ignoring what GAS may have set.

IMHO BFD does the right thing here if -mipsN is regarded as an
alias for the ISA's default architecture. (This isn't true when
using gcc 3.0, but it's the way it should be handled.)

> The UNKNOWN is a
> readelf bug, and actually E_MIPS_32BITMODE - perfect.

It actually isn't EF_MIPS_32BITMODE. UNKNOWN is the cpu type given
in the header flag (like 4111 or 3900). I wonder why readelf doesn't
show 32bitmode for you, support is already there.

Btw, it's possibly a good idea to ignore this part of the header flags
for cpu's not defined there. At least it would avoid confusion. :-)

[snip]
>  /* True if -mgp32 was passed.  */
> -static int file_mips_gp32 = 0;
> +static int file_mips_gp32 = -1;
>  
>  /* True if -mfp32 was passed.  */
> -static int file_mips_fp32 = 0;
> +static int file_mips_fp32 = -1;
>  
>  /* This is the struct we use to hold the current set of options.  Note
>     that we must set the isa field to ISA_UNKNOWN and the mips16 field to
> @@ -1077,6 +1077,37 @@ md_begin ()
>        assert (ci != NULL);
>        if (mips_opts.isa != ci->isa)
>  	{
> +#if 1
> +	  /* This code should go away, to be replaced with the block below it.

Err, no. :-) Both blocks should be replaced by an error message.

> +	     Until GCC 3.1 has been released for some reasonable amount of time,
> +	     however, we need to support this.  */

There should also be a comment to change the file_mips_*
initializations back.

> +	  /* Translate -mipsN to the appropriate settings of file_mips_gp32
> +	     and file_mips_fp32.  Tag binaries as using the mipsN ISA.  */

This could be easily misunderstood, the ISA tagging isn't done
explicitly.

> +	  if (file_mips_gp32 < 0)
> +	    {
> +	      if (ISA_HAS_64BIT_REGS (mips_opts.isa))
> +		file_mips_gp32 = 0;
> +	      else
> +		file_mips_gp32 = 1;
> +	    }
> +	  if (file_mips_fp32 < 0)
> +	    {
> +	      if (ISA_HAS_64BIT_REGS (mips_opts.isa))
> +		file_mips_fp32 = 0;
> +	      else
> +		file_mips_fp32 = 1;
> +	    }
> +	  if (ISA_HAS_64BIT_REGS (mips_opts.isa))
> +	    {
> +	      if (mips_opts.abi == O32_ABI)
> +		mips_opts.abi = NO_ABI;
> +	    }

This breaks e.g. -march=r8000 -mips3 -mabi=32. Hopefully nobody
needs it.


Thiemo