Split Driver.Env module

This commit splits the GHC.Driver.Env module creating a separate
GHC.Driver.Env.Types module where HscEnv and Hsc would live. This
will pave the way to the structured error values by avoiding one
boot module later down the line.

4 files changed, 156 insertions, 135 deletions

diff --git a/compiler/GHC/Driver/Env.hs b/compiler/GHC/Driver/Env.hs
index 596ea936ca..1dfb88f8e4 100644
--- a/compiler/GHC/Driver/Env.hs
+++ b/compiler/GHC/Driver/Env.hs
@@ -29,11 +29,9 @@ import GHC.Prelude
 
 import GHC.Driver.Ppr
 import GHC.Driver.Session
-import {-# SOURCE #-} GHC.Driver.Plugins
 
 import GHC.Runtime.Context
-import GHC.Runtime.Interpreter.Types (Interp)
-import GHC.Linker.Types ( Loader )
+import GHC.Driver.Env.Types ( Hsc(..), HscEnv(..) )
 
 import GHC.Unit
 import GHC.Unit.Module.ModGuts
@@ -43,7 +41,6 @@ import GHC.Unit.Module.Deps
 import GHC.Unit.Home.ModInfo
 import GHC.Unit.Env
 import GHC.Unit.External
-import GHC.Unit.Finder.Types
 
 import GHC.Core         ( CoreRule )
 import GHC.Core.FamInstEnv
@@ -52,10 +49,7 @@ import GHC.Core.InstEnv ( ClsInst )
 import GHC.Types.Annotations ( Annotation, AnnEnv, mkAnnEnv, plusAnnEnv )
 import GHC.Types.CompleteMatch
 import GHC.Types.Name
-import GHC.Types.Name.Cache
 import GHC.Types.Name.Env
-import GHC.Types.Target
-import GHC.Types.TypeEnv
 import GHC.Types.TyThing
 
 import GHC.Builtin.Names ( gHC_PRIM )
@@ -63,36 +57,15 @@ import GHC.Builtin.Names ( gHC_PRIM )
 import GHC.Data.Maybe
 import GHC.Data.Bag
 
-import GHC.Unit.Module.Graph
-
 import GHC.Utils.Outputable
 import GHC.Utils.Monad
 import GHC.Utils.Error
 import GHC.Utils.Panic
 import GHC.Utils.Misc
 
-import Control.Monad    ( guard, ap )
+import Control.Monad    ( guard )
 import Data.IORef
 
--- | The Hsc monad: Passing an environment and warning state
-newtype Hsc a = Hsc (HscEnv -> WarningMessages -> IO (a, WarningMessages))
-    deriving (Functor)
-
-instance Applicative Hsc where
-    pure a = Hsc $ \_ w -> return (a, w)
-    (<*>) = ap
-
-instance Monad Hsc where
-    Hsc m >>= k = Hsc $ \e w -> do (a, w1) <- m e w
-                                   case k a of
-                                       Hsc k' -> k' e w1
-
-instance MonadIO Hsc where
-    liftIO io = Hsc $ \_ w -> do a <- io; return (a, w)
-
-instance HasDynFlags Hsc where
-    getDynFlags = Hsc $ \e w -> return (hsc_dflags e, w)
-
 runHsc :: HscEnv -> Hsc a -> IO a
 runHsc hsc_env (Hsc hsc) = do
     (a, w) <- hsc hsc_env emptyBag
@@ -112,111 +85,6 @@ mkInteractiveHscEnv hsc_env =
 runInteractiveHsc :: HscEnv -> Hsc a -> IO a
 runInteractiveHsc hsc_env = runHsc (mkInteractiveHscEnv hsc_env)
 
--- | HscEnv is like 'GHC.Driver.Monad.Session', except that some of the fields are immutable.
--- An HscEnv is used to compile a single module from plain Haskell source
--- code (after preprocessing) to either C, assembly or C--. It's also used
--- to store the dynamic linker state to allow for multiple linkers in the
--- same address space.
--- Things like the module graph don't change during a single compilation.
---
--- Historical note: \"hsc\" used to be the name of the compiler binary,
--- when there was a separate driver and compiler.  To compile a single
--- module, the driver would invoke hsc on the source code... so nowadays
--- we think of hsc as the layer of the compiler that deals with compiling
--- a single module.
-data HscEnv
-  = HscEnv {
-        hsc_dflags :: DynFlags,
-                -- ^ The dynamic flag settings
-
-        hsc_targets :: [Target],
-                -- ^ The targets (or roots) of the current session
-
-        hsc_mod_graph :: ModuleGraph,
-                -- ^ The module graph of the current session
-
-        hsc_IC :: InteractiveContext,
-                -- ^ The context for evaluating interactive statements
-
-        hsc_HPT    :: HomePackageTable,
-                -- ^ The home package table describes already-compiled
-                -- home-package modules, /excluding/ the module we
-                -- are compiling right now.
-                -- (In one-shot mode the current module is the only
-                -- home-package module, so hsc_HPT is empty.  All other
-                -- modules count as \"external-package\" modules.
-                -- However, even in GHCi mode, hi-boot interfaces are
-                -- demand-loaded into the external-package table.)
-                --
-                -- 'hsc_HPT' is not mutable because we only demand-load
-                -- external packages; the home package is eagerly
-                -- loaded, module by module, by the compilation manager.
-                --
-                -- The HPT may contain modules compiled earlier by @--make@
-                -- but not actually below the current module in the dependency
-                -- graph.
-                --
-                -- (This changes a previous invariant: changed Jan 05.)
-
-        hsc_EPS :: {-# UNPACK #-} !(IORef ExternalPackageState),
-                -- ^ Information about the currently loaded external packages.
-                -- This is mutable because packages will be demand-loaded during
-                -- a compilation run as required.
-
-        hsc_NC  :: {-# UNPACK #-} !(IORef NameCache),
-                -- ^ As with 'hsc_EPS', this is side-effected by compiling to
-                -- reflect sucking in interface files.  They cache the state of
-                -- external interface files, in effect.
-
-        hsc_FC   :: {-# UNPACK #-} !(IORef FinderCache),
-                -- ^ The cached result of performing finding in the file system
-
-        hsc_type_env_var :: Maybe (Module, IORef TypeEnv)
-                -- ^ Used for one-shot compilation only, to initialise
-                -- the 'IfGblEnv'. See 'GHC.Tc.Utils.tcg_type_env_var' for
-                -- 'GHC.Tc.Utils.TcGblEnv'.  See also Note [hsc_type_env_var hack]
-
-        , hsc_interp :: Maybe Interp
-                -- ^ target code interpreter (if any) to use for TH and GHCi.
-                -- See Note [Target code interpreter]
-
-        , hsc_loader :: Loader
-                -- ^ Loader (dynamic linker)
-
-        , hsc_plugins :: ![LoadedPlugin]
-                -- ^ plugins dynamically loaded after processing arguments. What
-                -- will be loaded here is directed by DynFlags.pluginModNames.
-                -- Arguments are loaded from DynFlags.pluginModNameOpts.
-                --
-                -- The purpose of this field is to cache the plugins so they
-                -- don't have to be loaded each time they are needed.  See
-                -- 'GHC.Runtime.Loader.initializePlugins'.
-
-        , hsc_static_plugins :: ![StaticPlugin]
-                -- ^ static plugins which do not need dynamic loading. These plugins are
-                -- intended to be added by GHC API users directly to this list.
-                --
-                -- To add dynamically loaded plugins through the GHC API see
-                -- 'addPluginModuleName' instead.
-
-        , hsc_unit_dbs :: !(Maybe [UnitDatabase UnitId])
-                -- ^ Stack of unit databases for the target platform.
-                --
-                -- This field is populated with the result of `initUnits`.
-                --
-                -- 'Nothing' means the databases have never been read from disk.
-                --
-                -- Usually we don't reload the databases from disk if they are
-                -- cached, even if the database flags changed!
-
-        , hsc_unit_env :: UnitEnv
-                -- ^ Unit environment (unit state, home unit, etc.).
-                --
-                -- Initialized from the databases cached in 'hsc_unit_dbs' and
-                -- from the DynFlags.
- }
-
-
 hsc_home_unit :: HscEnv -> HomeUnit
 hsc_home_unit = ue_home_unit . hsc_unit_env
 
diff --git a/compiler/GHC/Driver/Env/Types.hs b/compiler/GHC/Driver/Env/Types.hs
new file mode 100644
index 0000000000..f4ded1381c
--- /dev/null
+++ b/compiler/GHC/Driver/Env/Types.hs
@@ -0,0 +1,151 @@
+{-# LANGUAGE DeriveFunctor #-}
+module GHC.Driver.Env.Types
+  ( Hsc(..)
+  , HscEnv(..)
+  ) where
+
+import GHC.Driver.Session ( DynFlags, HasDynFlags(..) )
+import GHC.Linker.Types ( Loader )
+import GHC.Prelude
+import GHC.Runtime.Context
+import GHC.Runtime.Interpreter.Types ( Interp )
+import GHC.Types.Error ( WarningMessages )
+import GHC.Types.Name.Cache
+import GHC.Types.Target
+import GHC.Types.TypeEnv
+import GHC.Unit.External
+import GHC.Unit.Finder.Types
+import GHC.Unit.Home.ModInfo
+import GHC.Unit.Module.Graph
+import GHC.Unit.Env
+import GHC.Unit.State
+import GHC.Unit.Types
+import {-# SOURCE #-} GHC.Driver.Plugins
+
+import Control.Monad ( ap )
+import Control.Monad.IO.Class
+import Data.IORef
+
+-- | The Hsc monad: Passing an environment and warning state
+newtype Hsc a = Hsc (HscEnv -> WarningMessages -> IO (a, WarningMessages))
+    deriving (Functor)
+
+instance Applicative Hsc where
+    pure a = Hsc $ \_ w -> return (a, w)
+    (<*>) = ap
+
+instance Monad Hsc where
+    Hsc m >>= k = Hsc $ \e w -> do (a, w1) <- m e w
+                                   case k a of
+                                       Hsc k' -> k' e w1
+
+instance MonadIO Hsc where
+    liftIO io = Hsc $ \_ w -> do a <- io; return (a, w)
+
+instance HasDynFlags Hsc where
+    getDynFlags = Hsc $ \e w -> return (hsc_dflags e, w)
+
+-- | HscEnv is like 'GHC.Driver.Monad.Session', except that some of the fields are immutable.
+-- An HscEnv is used to compile a single module from plain Haskell source
+-- code (after preprocessing) to either C, assembly or C--. It's also used
+-- to store the dynamic linker state to allow for multiple linkers in the
+-- same address space.
+-- Things like the module graph don't change during a single compilation.
+--
+-- Historical note: \"hsc\" used to be the name of the compiler binary,
+-- when there was a separate driver and compiler.  To compile a single
+-- module, the driver would invoke hsc on the source code... so nowadays
+-- we think of hsc as the layer of the compiler that deals with compiling
+-- a single module.
+data HscEnv
+  = HscEnv {
+        hsc_dflags :: DynFlags,
+                -- ^ The dynamic flag settings
+
+        hsc_targets :: [Target],
+                -- ^ The targets (or roots) of the current session
+
+        hsc_mod_graph :: ModuleGraph,
+                -- ^ The module graph of the current session
+
+        hsc_IC :: InteractiveContext,
+                -- ^ The context for evaluating interactive statements
+
+        hsc_HPT    :: HomePackageTable,
+                -- ^ The home package table describes already-compiled
+                -- home-package modules, /excluding/ the module we
+                -- are compiling right now.
+                -- (In one-shot mode the current module is the only
+                -- home-package module, so hsc_HPT is empty.  All other
+                -- modules count as \"external-package\" modules.
+                -- However, even in GHCi mode, hi-boot interfaces are
+                -- demand-loaded into the external-package table.)
+                --
+                -- 'hsc_HPT' is not mutable because we only demand-load
+                -- external packages; the home package is eagerly
+                -- loaded, module by module, by the compilation manager.
+                --
+                -- The HPT may contain modules compiled earlier by @--make@
+                -- but not actually below the current module in the dependency
+                -- graph.
+                --
+                -- (This changes a previous invariant: changed Jan 05.)
+
+        hsc_EPS :: {-# UNPACK #-} !(IORef ExternalPackageState),
+                -- ^ Information about the currently loaded external packages.
+                -- This is mutable because packages will be demand-loaded during
+                -- a compilation run as required.
+
+        hsc_NC  :: {-# UNPACK #-} !(IORef NameCache),
+                -- ^ As with 'hsc_EPS', this is side-effected by compiling to
+                -- reflect sucking in interface files.  They cache the state of
+                -- external interface files, in effect.
+
+        hsc_FC   :: {-# UNPACK #-} !(IORef FinderCache),
+                -- ^ The cached result of performing finding in the file system
+
+        hsc_type_env_var :: Maybe (Module, IORef TypeEnv)
+                -- ^ Used for one-shot compilation only, to initialise
+                -- the 'IfGblEnv'. See 'GHC.Tc.Utils.tcg_type_env_var' for
+                -- 'GHC.Tc.Utils.TcGblEnv'.  See also Note [hsc_type_env_var hack]
+
+        , hsc_interp :: Maybe Interp
+                -- ^ target code interpreter (if any) to use for TH and GHCi.
+                -- See Note [Target code interpreter]
+
+        , hsc_loader :: Loader
+                -- ^ Loader (dynamic linker)
+
+        , hsc_plugins :: ![LoadedPlugin]
+                -- ^ plugins dynamically loaded after processing arguments. What
+                -- will be loaded here is directed by DynFlags.pluginModNames.
+                -- Arguments are loaded from DynFlags.pluginModNameOpts.
+                --
+                -- The purpose of this field is to cache the plugins so they
+                -- don't have to be loaded each time they are needed.  See
+                -- 'GHC.Runtime.Loader.initializePlugins'.
+
+        , hsc_static_plugins :: ![StaticPlugin]
+                -- ^ static plugins which do not need dynamic loading. These plugins are
+                -- intended to be added by GHC API users directly to this list.
+                --
+                -- To add dynamically loaded plugins through the GHC API see
+                -- 'addPluginModuleName' instead.
+
+        , hsc_unit_dbs :: !(Maybe [UnitDatabase UnitId])
+                -- ^ Stack of unit databases for the target platform.
+                --
+                -- This field is populated with the result of `initUnits`.
+                --
+                -- 'Nothing' means the databases have never been read from disk.
+                --
+                -- Usually we don't reload the databases from disk if they are
+                -- cached, even if the database flags changed!
+
+        , hsc_unit_env :: UnitEnv
+                -- ^ Unit environment (unit state, home unit, etc.).
+                --
+                -- Initialized from the databases cached in 'hsc_unit_dbs' and
+                -- from the DynFlags.
+ }
+
diff --git a/compiler/ghc.cabal.in b/compiler/ghc.cabal.in
index 13b877fd44..323940d925 100644
--- a/compiler/ghc.cabal.in
+++ b/compiler/ghc.cabal.in
@@ -384,6 +384,7 @@ Library
         GHC.Driver.CodeOutput
         GHC.Driver.Config
         GHC.Driver.Env
+        GHC.Driver.Env.Types
         GHC.Driver.Flags
         GHC.Driver.Hooks
         GHC.Driver.Main
diff --git a/testsuite/tests/parser/should_run/CountParserDeps.stdout b/testsuite/tests/parser/should_run/CountParserDeps.stdout
index 9c3db2105a..332c15123f 100644
--- a/testsuite/tests/parser/should_run/CountParserDeps.stdout
+++ b/testsuite/tests/parser/should_run/CountParserDeps.stdout
@@ -1,4 +1,4 @@
-Found 236 parser module dependencies
+Found 237 parser module dependencies
 GHC.Builtin.Names
 GHC.Builtin.PrimOps
 GHC.Builtin.Types
@@ -80,6 +80,7 @@ GHC.Driver.Backend
 GHC.Driver.Backpack.Syntax
 GHC.Driver.CmdLine
 GHC.Driver.Env
+GHC.Driver.Env.Types
 GHC.Driver.Flags
 GHC.Driver.Hooks
 GHC.Driver.Monad