Hi Simon, On May 30, 2007, at 4:05 PM, Simon Marlow wrote:
Gregory Wright wrote:
I have put a binary distribution of ghc-6.6.1 for FreeBSD/amd64 at http://www.haskell.org/ghc/dist/6.6.1/ghc-6.6.1-x86_64-unknown- freebsd.tar.bz2
yay! Ian will supply a link from the download page in due course, I'm sure.
I still owe you some source patches to make the compiler build out of the box. If 6.6.1 is the end of the line, would you prefer that these be against HEAD? Should I ask for push permission or just send these via the usual darcs send route (now possible, since darcs builds on x86_64)?
The x86-64 (or amd64 if you like) Linux port doesn't do relocation of data references outside 2Gb. It is the subject of this bug:
http://hackage.haskell.org/trac/ghc/ticket/781
the underlying problem is that the relocatable reference is only 32 bits, because we're working in the small memory model, but the address of the symbol might be outside the current 2Gb slice, because it's in a shared library somewhere. The system linker solves this by relocating the data itself from the shared library into the main program's 2Gb slice (I think), but we can't do this in GHCi.
Hmm. I would have thought that the absolute addresses of static data in the shared library would have been resolved by the run time loader and written into the global offset table. It seems that all of the shared libraries on FreeBSD/amd64 are loaded at addresses above 2 GB, e.g., above 0x800000000. Perhaps rtld allocates space below 2GB and fills in adjusts the GOT to point to the data in lower memory. (There's not very much of it). I'll have to think about this a while.
Fortunately most code doesn't reference static data from shared libraries, so we get away with it most of the time.
FreeBSD/amd64 seems to make a lot of references to static data. When I edited the Linker to ignore out of range relocations and print a message I got dozens while starting GHCi. Best Wishes, Greg