I've built the GHC compiler along with libraries/base in the canonical way. Now, I want to compile base with my own compiler frontend which will do some analysis. Here's what I've done so far: 1) I've compiled my frontend with the ghc-stage2 compiler and registered it. That works. 2) I've found the right GHC invocation which looks like this: "inplace/bin/ghc-stage1" -hisuf hi -osuf o -hcsuf hc -static -O0 -H64m -Wall -this-unit-id base-4.9.1.0 -hide-all-packages -i -ilibraries/base/. -ilibraries/base/dist-install/build -ilibraries/base/dist-install/build/autogen -Ilibraries/base/dist-install/build -Ilibraries/base/dist-install/build/autogen -Ilibraries/base/include -optP-DOPTIMISE_INTEGER_GCD_LCM -optP-include -optPlibraries/base/dist-install/build/autogen/cabal_macros.h -package-id ghc-prim-0.5.0.0 -package-id integer-gmp-1.0.0.1 -package-id rts -this-unit-id base -XHaskell2010 -O0 -no-user-package-db -rtsopts -Wno-trustworthy-safe -Wno-deprecated-flags -Wnoncanonical-monad-instances -odir libraries/base/dist-install/build -hidir libraries/base/dist-install/build -stubdir libraries/base/dist-install/build -dynamic-too $hsfile So I (1) changed stage1 to stage2, so that I could use plugins, (2) simply added --frontend GhcFrontendPlugin -package frontend and ran that on every file under base/ in a loop: https://gist.github.com/chrisdone/3ca64592aed2053606d8814f2fa5d772 That seems to work. I basically have what I wanted. But I'd rather be able to invoke make with e.g. GHC_COMPILER=inplace/ghc/stage2 and EXTRA_HC_OPTS=" --frontend GhcFrontendPlugin -package frontend". Is there an easy flag to do that? If not, can someone point me where in the makefile I could tweak this? Cheers