Latest update on getting GHC working 64-bit on Snow Leopard. I've been building 6.8.3, simply because it was the version I had running before so might give fewer problems. To get the compiler working, apply this patch (which I borrowed from the Darcs repository): diff -uit a/compiler/cmm/CLabel.hs b/compiler/cmm/CLabel.hs --- a/compiler/cmm/CLabel.hs +++ b/compiler/cmm/CLabel.hs @@ -816,6 +816,10 @@ pprDynamicLinkerAsmLabel :: DynamicLinkerLabelInfo -> CLabel -> SDoc #if x86_64_TARGET_ARCH && darwin_TARGET_OS +pprDynamicLinkerAsmLabel CodeStub lbl + = char 'L' <> pprCLabel lbl <> text "$stub" +pprDynamicLinkerAsmLabel SymbolPtr lbl + = char 'L' <> pprCLabel lbl <> text "$non_lazy_ptr" pprDynamicLinkerAsmLabel GotSymbolPtr lbl = pprCLabel lbl <> text "@GOTPCREL" pprDynamicLinkerAsmLabel GotSymbolOffset lbl Make sure you have a working 32-bit GHC as well as libraries (libgmp, etc).for both 32 and 64-bit architectures. Then say ./configure --build=x86_64-apple-darwin --host=x86_64-apple-darwin -- target=x86_64-apple-darwin make It will compile an x86_64 GHC for you, happily unaware that the GHC you're using for the build is a 32-bit one. The stage1 compiler is, of course, a 32-bit binary that produces 64-bit binaries. I found that the resulting compiler can build itself (stage3) and can say Hello World, so it looks like it works correctly. I've still not got GHCi working, though. I've managed to narrow down the source of the trouble with the linker in GHCi, and it looks like there are some bugs as well as missing parts, which is why it kept launching itself to the moon. Still working on that one: patch to follow. For now, you can at least compile your code and run it non-interactively. Barney.