Make Logger independent of DynFlags

Introduce LogFlags as a independent subset of DynFlags used for logging.
As a consequence in many places we don't have to pass both Logger and
DynFlags anymore.

The main reason for this refactoring is that I want to refactor the
systools interfaces: for now many systools functions use DynFlags both
to use the Logger and to fetch their parameters (e.g. ldInputs for the
linker). I'm interested in refactoring the way they fetch their
parameters (i.e. use dedicated XxxOpts data types instead of DynFlags)
for #19877. But if I did this refactoring before refactoring the Logger,
we would have duplicate parameters (e.g. ldInputs from DynFlags and
linkerInputs from LinkerOpts). Hence this patch first.

Some flags don't really belong to LogFlags because they are subsystem
specific (e.g. most DumpFlags). For example -ddump-asm should better be
passed in NCGConfig somehow. This patch doesn't fix this tight coupling:
the dump flags are part of the UI but they are passed all the way down
for example to infer the file name for the dumps.

Because LogFlags are a subset of the DynFlags, we must update the former
when the latter changes (not so often). As a consequence we now use
accessors to read/write DynFlags in HscEnv instead of using `hsc_dflags`
directly.

In the process I've also made some subsystems less dependent on DynFlags:

- CmmToAsm: by passing some missing flags via NCGConfig (see new fields
  in GHC.CmmToAsm.Config)
- Core.Opt.*:
    - by passing -dinline-check value into UnfoldingOpts
    - by fixing some Core passes interfaces (e.g. CallArity, FloatIn)
      that took DynFlags argument for no good reason.
    - as a side-effect GHC.Core.Opt.Pipeline.doCorePass is much less
      convoluted.

2 files changed, 4 insertions, 4 deletions

diff --git a/utils/check-exact/Parsers.hs b/utils/check-exact/Parsers.hs
index 4620ae3fa1..5d8b180cd4 100644
--- a/utils/check-exact/Parsers.hs
+++ b/utils/check-exact/Parsers.hs
@@ -53,7 +53,7 @@ import qualified GHC hiding (parseModule)
 import qualified Control.Monad.IO.Class as GHC
 import qualified GHC.Data.FastString    as GHC
 import qualified GHC.Data.StringBuffer  as GHC
-import qualified GHC.Driver.Config      as GHC
+import qualified GHC.Driver.Config.Parser as GHC
 import qualified GHC.Driver.Errors.Types as GHC
 import qualified GHC.Driver.Session     as GHC
 import qualified GHC.Parser             as GHC
diff --git a/utils/check-exact/Preprocess.hs b/utils/check-exact/Preprocess.hs
index 245305a677..a085648f36 100644
--- a/utils/check-exact/Preprocess.hs
+++ b/utils/check-exact/Preprocess.hs
@@ -18,7 +18,7 @@ import qualified GHC            as GHC hiding (parseModule)
 import qualified Control.Monad.IO.Class as GHC
 import qualified GHC.Data.FastString   as GHC
 import qualified GHC.Data.StringBuffer as GHC
-import qualified GHC.Driver.Config     as GHC
+import qualified GHC.Driver.Config.Parser as GHC
 import qualified GHC.Driver.Env        as GHC
 import qualified GHC.Driver.Errors.Types as GHC
 import qualified GHC.Driver.Phases     as GHC
@@ -209,8 +209,8 @@ getPreprocessedSrcDirectPrim :: (GHC.GhcMonad m)
                               -> m (String, GHC.StringBuffer, GHC.DynFlags)
 getPreprocessedSrcDirectPrim cppOptions src_fn = do
   hsc_env <- GHC.getSession
-  let dfs = GHC.hsc_dflags hsc_env
-      new_env = hsc_env { GHC.hsc_dflags = injectCppOptions cppOptions dfs }
+  let dflags = GHC.hsc_dflags hsc_env
+      new_env = GHC.hscSetFlags (injectCppOptions cppOptions dflags) hsc_env
   r <- GHC.liftIO $ GHC.preprocess new_env src_fn Nothing (Just (GHC.Cpp GHC.HsSrcFile))
   case r of
     Left err -> error $ showErrorMessages err