Produces invalid assembly when using `peek' and -fvia-c with new binutils on amd64

[laney]

I noticed this when rebuilding happstack-util on Ubuntu. A mail sent to debian-haskell can be found at [0], but I've since produced a minimal test case, attached. To reproduce this you need a new binutils (the ones in Debian unstable and Ubuntu Natty are sufficient to trigger the bug).

When using peek from Foreign.Storable and compiling via C, GHC produces code which generates invalid assembly:

  [1 of 1] Compiling Break            ( break.hs, break.o )
  /tmp/ghc4532_0/ghc4532_0.s: Assembler messages:

  /tmp/ghc4532_0/ghc4532_0.s:73:0:
       Error: .size expression does not evaluate to a constant

[0]  http://lists.debian.org/debian-haskell/2011/03/msg00088.html

[laney]

I forgot to explicitly mention that this works on i386 but not on amd64.

[igloo]

Thanks for the report.

See also #5043.

[igloo]

This is now "fixed", by turning -fvia-c into a no-op.

[simonmar]

We should also mention that the workaround for 7.0.3 and earlier is to not use -fvia-C.