A question about ghc-cabal

[Manuel M T Chakravarty]

After some changes to GHC's handling of DPH packages, I'm currently fighting with the build system.  In particular, I'm getting

> "inplace/bin/ghc-cabal" configure --with-ghc="/Users/chak/Code/ghc-test/inplace/bin/ghc-stage1" --with-ghc-pkg="/Users/chak/Code/ghc-test/inplace/bin/ghc-pkg" --with-gcc="/usr/bin/gcc" --configure-option=--with-cc="/usr/bin/gcc" --flag=include-ghc-prim --enable-shared --enable-library-for-ghci --with-hscolour="/Users/chak/bin/HsColour" --configure-option=CFLAGS="-Wall -march=i686 -m32 -isysroot /Developer/SDKs/MacOSX10.5.sdk -mmacosx-version-min=10.5 -fno-stack-protector  " --configure-option=LDFLAGS=" -march=i686 -m32 -isysroot /Developer/SDKs/MacOSX10.5.sdk -mmacosx-version-min=10.5  " --configure-option=CPPFLAGS=" -march=i686 -m32 -isysroot /Developer/SDKs/MacOSX10.5.sdk -mmacosx-version-min=10.5  " -fdph-this -- dist-install libraries/ghc-prim
> Configuring ghc-prim-0.2.0.0...
> <command line>: the dph-par package is not installed.
> To install it: "cabal install dph".

The error message is generated by GHC's package management (in main/Packages.lhs and I think I know why GHC emits it).  However, I don't understand why/how GHC is invoked by ghc-cabal.  I looked at the source (the function 'generate' seems to be the main code that is executed for this invocation) and it appears to only generate some config files.  I'd be grateful for any pointers on where GHC is invoked during the execution of ghc-cabal.  (I didn't find any info about this on the wiki.)

Manuel