Sigh.  As an inconvenient workaround, I tried adding {-# OPTIONS_GHC -dverbose-core2core #-} to GHC.Real, and then doing

        cabal new-run hadrian -- -c -j4 --flavour=quick --directory=".."

in hadrian/

That did recompile GHC.Real – but all the debug output disappeared!

I tried adding {-# OPTIONS_GHC -ddebug-output #-} as well, but that didn’t work.

I’m stuck – any ideas?

Simon

From: ghc-devs <ghc-devs-bounces@haskell.org> On Behalf Of Simon Peyton Jones via ghc-devs
Sent: 30 August 2018 12:12
To: Alp Mestanogullari <alp@well-typed.com>; Andrey Mokhov <andrey.mokhov@newcastle.ac.uk>
Cc: ghc-devs <ghc-devs@haskell.org>
Subject: Hadrian

Alp, Andrey

The old build system printed out every command line; and I often copy-paste that info to build single modules.

Eg currently, when trying to understand #15570 I see a suspicious GHC.Real.hi.  So I want to manually recompile GHC.Real (from base), adding some debug flags.  How can I get the right command line to do that from the build log?

Where is the “how to use Hadrian” wiki page?  I know you’ve been writing one.

Simon