Build Haskell modules accounting for TH

Creates a new module Distribution.Simple.GHC.Build.Modules which, in the
same spirit as ...GHC.Build.ExtraModules, defines a 'BuildM' action
which builds all the Haskell modules of the component being built.

This function clarifies and re-implements the logic of building Haskell
modules in the different possible ways, while accounting for
Template Haskell special "way requirements", which was previously
duplicated in a non-obvious manner in gbuild and buildOrReplLib.

The Note [Building Haskell modules accounting for TH] in that module
explains the big picture, and the implementation is re-done in light of
it.

A standalone part of the refactor of gbuild vs buildOrReplLib (haskell#9389)

Cabal/Cabal.cabal

@@ -88,7 +88,6 @@ library
     Distribution.Simple
     Distribution.Simple.Bench
     Distribution.Simple.Build
-    Distribution.Simple.Build.ExtraSources
     Distribution.Simple.Build.Macros
     Distribution.Simple.Build.Monad
     Distribution.Simple.Build.PackageInfoModule
@@ -334,8 +333,12 @@ library
     Distribution.Simple.Build.PackageInfoModule.Z
     Distribution.Simple.Build.PathsModule.Z
     Distribution.Simple.GHC.Build
-    Distribution.Simple.GHC.BuildOrRepl
+    Distribution.Simple.GHC.Build.ExtraSources
+    Distribution.Simple.GHC.Build.Link
+    Distribution.Simple.GHC.Build.Modules
+    Distribution.Simple.GHC.Build.Utils
     Distribution.Simple.GHC.BuildGeneric
+    Distribution.Simple.GHC.BuildOrRepl
     Distribution.Simple.GHC.EnvironmentParser
     Distribution.Simple.GHC.Internal
     Distribution.Simple.GHC.ImplInfo

Cabal/src/Distribution/Simple/Build/Monad.hs

@@ -1,11 +1,20 @@
 {-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE NamedFieldPuns #-}
-
 module Distribution.Simple.Build.Monad
   ( BuildM (..)
   , runBuildM
   , PreBuildComponentInputs (..)
 
+    -- * A few queries on @'BuildM'@
+  , buildVerbosity
+  , buildWhat
+  , buildComponent
+  , buildCLBI
+  , buildBI
+  , buildLBI
+  , buildCompiler
+  , buildTarget
+
     -- * Re-exports
   , BuildingWhat (..)
   , LocalBuildInfo (..)
@@ -20,6 +29,11 @@ import Control.Monad.Reader
 import Distribution.Simple.Setup (BuildingWhat (..), buildingWhatDistPref, buildingWhatVerbosity)
 import Distribution.Types.LocalBuildInfo
 import Distribution.Types.TargetInfo
+import Distribution.Verbosity
+import Distribution.Types.Component
+import Distribution.Types.ComponentLocalBuildInfo
+import Distribution.Types.BuildInfo
+import Distribution.Simple.Compiler
 
 -- | The information required for a build computation (@'BuildM'@)
 -- which is available right before building each component, i.e. the pre-build
@@ -35,9 +49,49 @@ data PreBuildComponentInputs = PreBuildComponentInputs
 
 -- | Computations carried out in the context of building a component (e.g. @'buildAllExtraSources'@)
 newtype BuildM a = BuildM (PreBuildComponentInputs -> IO a)
-  deriving (Functor, Applicative, Monad) via ReaderT PreBuildComponentInputs IO
+  deriving (Functor, Applicative, Monad, MonadReader PreBuildComponentInputs, MonadIO) via ReaderT PreBuildComponentInputs IO
 
 -- | Run a 'BuildM' action, i.e. a computation in the context of building a component.
 runBuildM :: BuildingWhat -> LocalBuildInfo -> TargetInfo -> BuildM a -> IO a
 runBuildM buildingWhat localBuildInfo targetInfo (BuildM f) =
   f PreBuildComponentInputs{buildingWhat, localBuildInfo, targetInfo}
+{-# INLINE runBuildM #-}
+
+-- | Get the @'BuildingWhat'@ representing the kind of build we are doing with what flags (Normal vs Repl vs ...)
+buildWhat :: BuildM BuildingWhat
+buildWhat = asks buildingWhat
+{-# INLINE buildWhat #-}
+
+-- | Get the @'Verbosity'@ from the context the component being built is in.
+buildVerbosity :: BuildM Verbosity
+buildVerbosity = buildingWhatVerbosity <$> buildWhat
+{-# INLINE buildVerbosity #-}
+
+-- | Get the @'Component'@ being built.
+buildComponent :: BuildM Component
+buildComponent = asks (targetComponent . targetInfo)
+{-# INLINE buildComponent #-}
+
+-- | Get the @'ComponentLocalBuildInfo'@ for the component being built.
+buildCLBI :: BuildM ComponentLocalBuildInfo
+buildCLBI = asks (targetCLBI . targetInfo)
+{-# INLINE buildCLBI #-}
+
+-- | Get the @'BuildInfo'@ of the component being built.
+buildBI :: BuildM BuildInfo
+buildBI = componentBuildInfo <$> buildComponent
+{-# INLINE buildBI #-}
+
+-- | Get the @'LocalBuildInfo'@ of the component being built.
+buildLBI :: BuildM LocalBuildInfo
+buildLBI = asks localBuildInfo
+{-# INLINE buildLBI #-}
+
+buildCompiler :: BuildM Compiler
+buildCompiler = compiler <$> buildLBI
+{-# INLINE buildCompiler #-}
+
+-- | Get the @'TargetInfo'@ of the current component being built.
+buildTarget :: BuildM TargetInfo
+buildTarget = asks targetInfo
+

Cabal/src/Distribution/Simple/GHC.hs

@@ -56,7 +56,7 @@ module Distribution.Simple.GHC
   , libAbiHash
   , hcPkgInfo
   , registerPackage
-  , componentGhcOptions
+  , Internal.componentGhcOptions
   , Internal.componentCcGhcOptions
   , getGhcAppDir
   , getLibDir
@@ -95,12 +95,7 @@ import Distribution.Simple.BuildPaths
 import Distribution.Simple.Compiler
 import Distribution.Simple.Errors
 import Distribution.Simple.Flag (Flag (..), toFlag)
-import Distribution.Simple.GHC.Build
-  ( componentGhcOptions
-  , exeTargetName
-  , flibTargetName
-  , isDynamic
-  )
+import Distribution.Simple.GHC.Build.Utils
 import Distribution.Simple.GHC.EnvironmentParser
 import Distribution.Simple.GHC.ImplInfo
 import qualified Distribution.Simple.GHC.Internal as Internal
@@ -109,6 +104,7 @@ import Distribution.Simple.PackageIndex (InstalledPackageIndex)
 import qualified Distribution.Simple.PackageIndex as PackageIndex
 import Distribution.Simple.Program
 import Distribution.Simple.Program.Builtin (runghcProgram)
+import Distribution.Types.TargetInfo
 import Distribution.Simple.Program.GHC
 import qualified Distribution.Simple.Program.HcPkg as HcPkg
 import qualified Distribution.Simple.Program.Strip as Strip
@@ -137,7 +133,7 @@ import System.FilePath
   )
 import qualified System.Info
 #ifndef mingw32_HOST_OS
-import Distribution.Simple.GHC.Build (flibBuildName)
+import Distribution.Simple.GHC.Build.Utils (flibBuildName)
 import System.Directory (renameFile)
 import System.Posix (createSymbolicLink)
 #endif /* mingw32_HOST_OS */
@@ -579,7 +575,7 @@ buildLib
   -> Library
   -> ComponentLocalBuildInfo
   -> IO ()
-buildLib = buildOrReplLib . Left
+buildLib = buildOrReplLib . BuildNormal
 
 replLib
   :: ReplFlags
@@ -589,7 +585,7 @@ replLib
   -> Library
   -> ComponentLocalBuildInfo
   -> IO ()
-replLib = buildOrReplLib . Right
+replLib = buildOrReplLib . BuildRepl
 
 -- | Start a REPL without loading any source files.
 startInterpreter
@@ -632,7 +628,7 @@ replFLib
   -> ComponentLocalBuildInfo
   -> IO ()
 replFLib replFlags njobs pkg lbi =
-  gbuild (BuildRepl replFlags) njobs pkg lbi . GReplFLib (replReplOptions replFlags)
+  gbuild (BuildRepl replFlags) njobs pkg lbi . GReplFLib replFlags
 
 -- | Build an executable with GHC.
 buildExe
@@ -654,7 +650,7 @@ replExe
   -> ComponentLocalBuildInfo
   -> IO ()
 replExe replFlags njobs pkg lbi =
-  gbuild (BuildRepl replFlags) njobs pkg lbi . GReplExe (replReplOptions replFlags)
+  gbuild (BuildRepl replFlags) njobs pkg lbi . GReplExe replFlags
 
 -- | Extracts a String representing a hash of the ABI of a built
 -- library.  It can fail if the library has not yet been built.
@@ -671,7 +667,7 @@ libAbiHash verbosity _pkg_descr lbi lib clbi = do
     comp = compiler lbi
     platform = hostPlatform lbi
     vanillaArgs =
-      (componentGhcOptions verbosity lbi libBi clbi (componentBuildDir lbi clbi))
+      (Internal.componentGhcOptions verbosity lbi libBi clbi (componentBuildDir lbi clbi))
         `mappend` mempty
           { ghcOptMode = toFlag GhcModeAbiHash
           , ghcOptInputModules = toNubListR $ exposedModules lib