Can't compile GHC 6.8.2

[Simon Marlow]

Barney Stratford wrote:
> There's good news and bad news. The good news is that the compilation of
> my shiny almost-new GHC is complete. The bad news is, it won't link.
> It's grumbling about 
> 
> ld:
> /System/Fink/src/fink.build/ghc-6.8.2-1/ghc-6.8.2/rts/libHSrts.a(PrimOps.o)
> has external relocation entries in non-writable section (__TEXT,__text)
> for symbols:
> ___gmpn_cmp
> ___gmpn_gcd_1
> ___gmpz_fdiv_qr
> ___gmpz_init
> ___gmpz_tdiv_qr
> ___gmpz_com
> ___gmpz_xor
> ___gmpz_ior
> ___gmpz_and
> ___gmpz_divexact
> ___gmpz_tdiv_r
> ___gmpz_tdiv_q
> ___gmpz_gcd
> ___gmpz_mul
> ___gmpz_sub
> ___gmpz_add
> 
> Looking through the archives, it seems like this is an old favourite bug
> rearing its ugly head again. The suggested remedy of commenting out the
> line reading "SRC_HC_OPTS += -fvia-C" in the Makefile won't work, as
> that line isn't there anyway. The manpage for ld has an option
> "-read_only_relocs warning" that looks like it might suppress this
> problem, but I don't fully understand what it's doing.
> 
> What would you suggest?

The workaround is almost certainly to build the RTS with -fasm.  However, 
I'd be really pleased if someone could get to the bottom of this, so that 
we can fix the root cause.  You can get a look at the .s file generated for 
PrimOps by saying

  $ cd rts
  $ make PrimOps.s

(make sure you're still compiling via-C).  Have a look at the references to 
those symbols, do they look suspicious at all?  Try compiling the same 
module with -fasm, and compare the .s file with the via-C version.  Also 
you could try poking around in the .o file with objdump, and see what 
relocation entries are being generated in both cases.

Cheers,
	Simon