On 2001-07-13T16:55:57-0400, Ken Shan wrote:
Current hurdle: ghc-inplace doesn't seem to be finding its .hi files for basic stuff.
puffin:~$ cat Main.hs module Main where import IO main = putStrLn "Hello, world!"
puffin:~$ u/ghc-port/alpha/ghc/compiler/ghc-inplace Main.hs Main.hs:1: failed to load interface for `Prelude': Could not find interface file for `Prelude'
Main.hs:2: failed to load interface for `IO': Could not find interface file for `IO'
This problem was because struct dirent differs between i386-linux and alpha-osf3. I fixed it by running the intermediate C program generated by hsc2hs remotely on our alpha machine instead of locally on our linux machine. "Hello, world!" works now! Yay! So far, I've discovered 3 reasons why .hc files are not entirely portable across platforms. 1. ghc/includes/MachDeps.h, which is #included by some Haskell source files, in turn #includes ghc/includes/config.h, which differs from platform to platform. SOLUTION: Modify MachDeps.h to #include the config.h from alpha-osf3, even when compiling on i386-linux. 2. The .hs file produced by hsc2hs differs from platform to platform, because the intermediate C program it generates necessarily behaves differently on each platform. SOLUTION: Add "--keep-tmp-files" flag to hsc2hs. Run the intermediate C program over on alpha-osf3. 3. Liveness bitmaps are of different width (32 bits vs 64 bits) between platforms, and the compiler generates different HC code based on the width. SOLUTION: Make the compiler generate platform-independent HC code that uses newly defined preprocessor macros to switch between 32-bit and 64-bit liveness bitmaps at C compilation time. These fixes (especially #1) make me uneasy about the bootstrapping process. Here's my current limited understanding of the making of HC files: a. First we use the existing GHC to compile a new compiler (that produces unregisterised code) b. Second we use the new compiler to compile a new library (keeping the unregisterised HC files) -- This new library is compiled for use on alpha-osf3, not i386-linux, in terms of issues (1) and (2) above. c. Third we use the new compiler from (a), in conjuction with the new library from (b), to compile a doubly new compiler (that produces unregisterised code) (keeping the unregisterised HC files) -- This doubly new compiler is compiled for use on alpha-osf3, not i386-linux, in terms of issues (1) and (2) above. d. Finally we ship the HC files kept from steps (b) and (c) for use on the target platform Note that, in step (c), we run the i386-linux compiler from (a) with the alpha-osf3 library from (b). The library produced in (b) is incorrect as i386-linux code, but that's okay because all we want from (b) are the HC files anyway. Consequently, the doubly new compiler produced in (c) is also incorrect as i386-linux code. That's again okay because all we really want from step (c) are the HC files anyway. Just to make sure, though, could you please confirm the following:? In step (c), the once-new compiler uses (b) only as data, not as code. In other words, even though (b) is incorrect as i386-linux code (and so (c) is incorrect as i386-linux code), the HC files produced in (c) are still perfectly correct as alpha-osf3 code. -- Edit this signature at http://www.digitas.harvard.edu/cgi-bin/ken/sig See the sun in the midst of the rain. Scoop clear water from the heart of the fire.