For better or for worse, this message will be one full of questions... It took a couple (one? two? I can't remember) iterations of ghc building itself purely on the Alpha before the .hc files reached fixpoint... I suspect it's because the compiler on i386-linux didn't realise that it could fit an entire double in one word. I've been looking for test suites to run, to make myself more confident of the port. I found two likely suspects in the CVS repository, namely fptools/testsuite and fptools/ghc/tests. Neither of them pass without unexpected failures on a clean i386-linux build, though. Any suggestions? At what seems now to be a long time ago you said:
Once you have an unregisterised build working (& bootstrapped), you can start trying to get the mangler going for full registerised support. The mangler has Alpha support, but it is old and bound to be rotten to some extent.
Any suggestions for how I should start on this, and what to watch out for? The mangler looks, well, evil. (Time to glorify it, as was done to the driver?) Regarding our wanting to
- add some support for cross-compilation to the build system.
The only cross-compilation support I can see that isn't too hard to add would be documented procedures for shipping the "three wrinkles" between the build and target systems: ghc/includes/config.h, .hs output from hsc2hs, and ghc/compiler/main/Config.hs. Is this kind of support basically what you meant, or did you have something else in mind?
- write down exactly what one needs to do to make this work, and put the instructions in the build system documentation.
I'd be happy to write down what I did in the near future. It's basically the standard steps for creating .hc files, with the abovementioned "three wrinkles". (Provided that the patches I just sent are applied -- prod prod :).
SOLUTION: Modify MachDeps.h to #include the config.h from alpha-osf3, even when compiling on i386-linux.
Yep: for cross compilation of the .hc files, the first thing to do is run ./configure on the target platform and take the output back to the host.
I didn't overwrite the i386 config.h with the Alpha one -- I only changed MachDeps.h and ArrayBase.hs. Should I have taken the more drastic route of overwriting? By the way, why does MachDeps.h #define FLOAT_SIZE_IN_BYTES to be SIZEOF_DOUBLE rather than SIZEOF_FLOAT if SIZEOF_DOUBLE == SIZEOF_VOID_P?
The assertion in question is: /* make sure the info pointer is into text space */ ASSERT(q && (LOOKS_LIKE_GHC_INFO(GET_INFO(q)) || IS_HUGS_CONSTR_INFO(GET_INFO(q))));
It seems that the GC code is sensitive to the layout of the virtual memory address space. In particular, I had to change HEAP_BASE from 0x50000000 to 0x200000000L in MBlock.h to get GC to work even with -static.
So it doesn't work without -static? A HEAP_BASE change is not unexpected, it all depends where the system puts its shared libraries.
Okay, so with -static, I easily found the seemingly working setting of HEAP_BASE == 0x180000000L (with the help of some Alpha assembly programming documentation). Without -static, is there some way to (reliably?) know what HEAP_BASE should be set to? I'm not even sure if the HEAP_BASE setting is the problem, but it seems likely. (Specifically: When I looked at the assert failure core dump inside gdb, GET_INFO(q) did in fact look like ghc info to my human eyes; the reason LOOKS_LIKE_GHC_INFO(GET_INFO(q)) was false was that HEAP_ALLOCED(GET_INFO(q)) was true.) The getMBlocks function in MBlock.c does not check to make sure that the pointer returned by mmap() is the address it asked for. Should it? An entirely separate question: Why are there both rts/Linker.h and includes/Linker.h? -- Edit this signature at http://www.digitas.harvard.edu/cgi-bin/ken/sig Little can be said for Luxembourg.