Using GHC API to compile Haskell file

[Neil Mitchell]

Hi,

Is this the right place for GHC API queries? If not, is there anywhere better?

I want to compile a Haskell module, much like `ghc --make` or `ghc -c`
does. The sample code on the Haskell wiki
(https://wiki.haskell.org/GHC/As_a_library#A_Simple_Example),
StackOverflow (http://stackoverflow.com/a/5631338/160673) and in GHC
API slides (http://sneezy.cs.nott.ac.uk/fplunch/weblog/wp-content/uploads/2008/12/ghc-api-slidesnotes.pdf)
says:

    import GHC
    import GHC.Paths ( libdir )
    import DynFlags

    main =
        defaultErrorHandler defaultFatalMessager defaultFlushOut $ do
          runGhc (Just libdir) $ do
            dflags <- getSessionDynFlags
            setSessionDynFlags dflags
            target <- guessTarget "Test.hs" Nothing
            setTargets [target]
            load LoadAllTargets

However, given a `Test.hs` file with the contents `main = print 1`, I
get the error:

    C:/Program Files (x86)/MinGHC-7.8.3/ghc-7.8.3/mingw/bin/ld.exe:
cannot find -lHSbase-4.7.0.1-ghc7.8.3
    C:/Program Files (x86)/MinGHC-7.8.3/ghc-7.8.3/mingw/bin/ld.exe:
cannot find -lHSinteger-gmp-0.5.1.0-ghc7.8.3
    C:/Program Files (x86)/MinGHC-7.8.3/ghc-7.8.3/mingw/bin/ld.exe:
cannot find -lHSghc-prim-0.3.1.0-ghc7.8.3
    C:/Program Files (x86)/MinGHC-7.8.3/ghc-7.8.3/mingw/bin/ld.exe:
cannot find -lHSrts-ghc7.8.3
    C:/Program Files (x86)/MinGHC-7.8.3/ghc-7.8.3/mingw/bin/ld.exe:
cannot find -lffi-6
    collect2: ld returned 1 exit status

Has the recipe changed?

By turning up the verbosity, I was able to compare the command line
passed to the linker. The failing GHC API call contains:

    "-lHSbase-4.7.0.1-ghc7.8.3" "-lHSinteger-gmp-0.5.1.0-ghc7.8.3"
"-lHSghc-prim-0.3.1.0-ghc7.8.3" "-lHSrts-ghc7.8.3" "-lffi-6"

While the succeeding ghc --make contains:

    "-lHSbase-4.7.0.1" "-lHSinteger-gmp-0.5.1.0"
"-lHSghc-prim-0.3.1.0" "-lHSrts" "-lCffi-6"

Should I be getting DynFlags differently to influence those link variables?

Thanks, Neil