DynFlags.hs

-------------------------------------------------------------------------------
--
-- | Dynamic flags
--
-- Most flags are dynamic flags, which means they can change from compilation
-- to compilation using @OPTIONS_GHC@ pragmas, and in a multi-session GHC each
-- session can be using different dynamic flags. Dynamic flags can also be set
-- at the prompt in GHCi.
--
-- (c) The University of Glasgow 2005
--
-------------------------------------------------------------------------------

module DynFlags (
        -- * Dynamic flags and associated configuration types
        DynFlag(..),
        WarningFlag(..),
        ExtensionFlag(..),
        Language(..),
        LogAction, FlushOut(..), FlushErr(..),
        ProfAuto(..),
        glasgowExtsFlags,
        dopt,
        dopt_set,
        dopt_unset,
        wopt,
        wopt_set,
        wopt_unset,
        xopt,
        xopt_set,
        xopt_unset,
        lang_set,
        DynFlags(..),
        HasDynFlags(..), ContainsDynFlags(..),
        RtsOptsEnabled(..),
        HscTarget(..), isObjectTarget, defaultObjectTarget,
        targetRetainsAllBindings,
        GhcMode(..), isOneShot,
        GhcLink(..), isNoLink,
        PackageFlag(..),
        Option(..), showOpt,
        DynLibLoader(..),
        fFlags, fWarningFlags, fLangFlags, xFlags,
        wayNames, dynFlagDependencies,

        -- ** Safe Haskell
        SafeHaskellMode(..),
        safeHaskellOn, safeImportsOn, safeLanguageOn, safeInferOn,
        packageTrustOn,
        safeDirectImpsReq, safeImplicitImpsReq,
        unsafeFlags,

        -- ** System tool settings and locations
        Settings(..),
        targetPlatform,
        ghcUsagePath, ghciUsagePath, topDir, tmpDir, rawSettings,
        extraGccViaCFlags, systemPackageConfig,
        pgm_L, pgm_P, pgm_F, pgm_c, pgm_s, pgm_a, pgm_l, pgm_dll, pgm_T,
        pgm_sysman, pgm_windres, pgm_lo, pgm_lc,
        opt_L, opt_P, opt_F, opt_c, opt_a, opt_l,
        opt_windres, opt_lo, opt_lc,


        -- ** Manipulating DynFlags
        defaultDynFlags,                -- Settings -> DynFlags
        initDynFlags,                   -- DynFlags -> IO DynFlags
        defaultLogAction,
        defaultFlushOut,
        defaultFlushErr,

        getOpts,                        -- DynFlags -> (DynFlags -> [a]) -> [a]
        getVerbFlags,
        updOptLevel,
        setTmpDir,
        setPackageName,
        doingTickyProfiling,

        -- ** Parsing DynFlags
        parseDynamicFlagsCmdLine,
        parseDynamicFilePragma,
        allFlags,

        supportedLanguagesAndExtensions,

        -- ** DynFlag C compiler options
        picCCOpts,

        -- * Configuration of the stg-to-stg passes
        StgToDo(..),
        getStgToDo,

        -- * Compiler configuration suitable for display to the user
        compilerInfo
#ifdef GHCI
-- Only in stage 2 can we be sure that the RTS
-- exposes the appropriate runtime boolean
      , rtsIsProfiled
#endif
  ) where

#include "HsVersions.h"

import Platform
import Module
import PackageConfig
import PrelNames        ( mAIN )
import StaticFlags
import {-# SOURCE #-} Packages (PackageState)
import DriverPhases     ( Phase(..), phaseInputExt )
import Config
import CmdLineParser
import Constants        ( mAX_CONTEXT_REDUCTION_DEPTH )
import Panic
import Util
import Maybes           ( orElse )
import SrcLoc
import FastString
import Outputable
#ifdef GHCI
import Foreign.C        ( CInt(..) )
#endif
import {-# SOURCE #-} ErrUtils ( Severity(..), MsgDoc, mkLocMessage )

#ifdef GHCI
import System.IO.Unsafe ( unsafePerformIO )
#endif
import Data.IORef
import Control.Monad    ( when )

import Data.Char
import Data.List
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Set (Set)
import qualified Data.Set as Set
import System.FilePath
import System.IO

import Data.IntSet (IntSet)
import qualified Data.IntSet as IntSet

-- -----------------------------------------------------------------------------
-- DynFlags

-- | Enumerates the simple on-or-off dynamic flags
data DynFlag

   -- debugging flags
   = Opt_D_dump_cmm
   | Opt_D_dump_raw_cmm
   | Opt_D_dump_cmmz
   | Opt_D_dump_cmmz_pretty
   -- All of the cmmz subflags (there are a lot!)  Automatically
   -- enabled if you run -ddump-cmmz
   | Opt_D_dump_cmmz_cbe
   | Opt_D_dump_cmmz_proc
   | Opt_D_dump_cmmz_spills
   | Opt_D_dump_cmmz_rewrite
   | Opt_D_dump_cmmz_dead
   | Opt_D_dump_cmmz_stub
   | Opt_D_dump_cmmz_sp
   | Opt_D_dump_cmmz_procmap
   | Opt_D_dump_cmmz_split
   | Opt_D_dump_cmmz_lower
   | Opt_D_dump_cmmz_info
   | Opt_D_dump_cmmz_cafs
   -- end cmmz subflags
   | Opt_D_dump_cps_cmm
   | Opt_D_dump_cvt_cmm
   | Opt_D_dump_asm
   | Opt_D_dump_asm_native
   | Opt_D_dump_asm_liveness
   | Opt_D_dump_asm_coalesce
   | Opt_D_dump_asm_regalloc
   | Opt_D_dump_asm_regalloc_stages
   | Opt_D_dump_asm_conflicts
   | Opt_D_dump_asm_stats
   | Opt_D_dump_asm_expanded
   | Opt_D_dump_llvm
   | Opt_D_dump_core_stats
   | Opt_D_dump_cpranal
   | Opt_D_dump_deriv
   | Opt_D_dump_ds
   | Opt_D_dump_flatC
   | Opt_D_dump_foreign
   | Opt_D_dump_inlinings
   | Opt_D_dump_rule_firings
   | Opt_D_dump_rule_rewrites
   | Opt_D_dump_occur_anal
   | Opt_D_dump_parsed
   | Opt_D_dump_rn
   | Opt_D_dump_core_pipeline -- TODO FIXME: dump after simplifier stats
   | Opt_D_dump_simpl
   | Opt_D_dump_simpl_iterations
   | Opt_D_dump_simpl_phases
   | Opt_D_dump_spec
   | Opt_D_dump_prep
   | Opt_D_dump_stg
   | Opt_D_dump_stranal
   | Opt_D_dump_tc
   | Opt_D_dump_types
   | Opt_D_dump_rules
   | Opt_D_dump_cse
   | Opt_D_dump_worker_wrapper
   | Opt_D_dump_rn_trace
   | Opt_D_dump_rn_stats
   | Opt_D_dump_opt_cmm
   | Opt_D_dump_simpl_stats
   | Opt_D_dump_cs_trace -- Constraint solver in type checker
   | Opt_D_dump_tc_trace
   | Opt_D_dump_if_trace
   | Opt_D_dump_vt_trace
   | Opt_D_dump_splices
   | Opt_D_dump_BCOs
   | Opt_D_dump_vect
   | Opt_D_dump_ticked
   | Opt_D_dump_rtti
   | Opt_D_source_stats
   | Opt_D_verbose_core2core
   | Opt_D_verbose_stg2stg
   | Opt_D_dump_hi
   | Opt_D_dump_hi_diffs
   | Opt_D_dump_minimal_imports
   | Opt_D_dump_mod_cycles
   | Opt_D_dump_view_pattern_commoning
   | Opt_D_faststring_stats
   | Opt_DumpToFile                     -- ^ Append dump output to files instead of stdout.
   | Opt_D_no_debug_output
   | Opt_DoCoreLinting
   | Opt_DoStgLinting
   | Opt_DoCmmLinting
   | Opt_DoAsmLinting
   | Opt_NoLlvmMangler                 -- hidden flag

   | Opt_WarnIsError                    -- -Werror; makes warnings fatal

   | Opt_PrintExplicitForalls

   -- optimisation opts
   | Opt_Strictness
   | Opt_FullLaziness
   | Opt_FloatIn
   | Opt_Specialise
   | Opt_StaticArgumentTransformation
   | Opt_CSE
   | Opt_LiberateCase
   | Opt_SpecConstr
   | Opt_DoLambdaEtaExpansion
   | Opt_IgnoreAsserts
   | Opt_DoEtaReduction
   | Opt_CaseMerge
   | Opt_UnboxStrictFields
   | Opt_DictsCheap
   | Opt_EnableRewriteRules             -- Apply rewrite rules during simplification
   | Opt_Vectorise
   | Opt_AvoidVect
   | Opt_RegsGraph                      -- do graph coloring register allocation
   | Opt_RegsIterative                  -- do iterative coalescing graph coloring register allocation
   | Opt_PedanticBottoms                -- Be picky about how we treat bottom
   | Opt_LlvmTBAA                       -- Use LLVM TBAA infastructure for improving AA (hidden flag)
   | Opt_RegLiveness                    -- Use the STG Reg liveness information (hidden flag)

   -- Interface files
   | Opt_IgnoreInterfacePragmas
   | Opt_OmitInterfacePragmas
   | Opt_ExposeAllUnfoldings

   -- profiling opts
   | Opt_AutoSccsOnIndividualCafs
   | Opt_ProfCountEntries

   -- misc opts
   | Opt_Pp
   | Opt_ForceRecomp
   | Opt_ExcessPrecision
   | Opt_EagerBlackHoling
   | Opt_ReadUserPackageConf
   | Opt_NoHsMain
   | Opt_SplitObjs
   | Opt_StgStats
   | Opt_HideAllPackages
   | Opt_PrintBindResult
   | Opt_Haddock
   | Opt_HaddockOptions
   | Opt_Hpc_No_Auto
   | Opt_BreakOnException
   | Opt_BreakOnError
   | Opt_PrintEvldWithShow
   | Opt_PrintBindContents
   | Opt_GenManifest
   | Opt_EmbedManifest
   | Opt_EmitExternalCore
   | Opt_SharedImplib
   | Opt_BuildingCabalPackage
   | Opt_SSE2
   | Opt_SSE4_2
   | Opt_GhciSandbox
   | Opt_GhciHistory
   | Opt_HelpfulErrors
   | Opt_DeferTypeErrors

   -- temporary flags
   | Opt_RunCPS
   | Opt_RunCPSZ
   | Opt_AutoLinkPackages
   | Opt_ImplicitImportQualified
   | Opt_TryNewCodeGen

   -- keeping stuff
   | Opt_KeepHiDiffs
   | Opt_KeepHcFiles
   | Opt_KeepSFiles
   | Opt_KeepTmpFiles
   | Opt_KeepRawTokenStream
   | Opt_KeepLlvmFiles

   -- safe haskell flags
   | Opt_DistrustAllPackages
   | Opt_PackageTrust

   deriving (Eq, Show, Enum)

data WarningFlag =
     Opt_WarnDuplicateExports
   | Opt_WarnHiShadows
   | Opt_WarnImplicitPrelude
   | Opt_WarnIncompletePatterns
   | Opt_WarnIncompleteUniPatterns
   | Opt_WarnIncompletePatternsRecUpd
   | Opt_WarnMissingFields
   | Opt_WarnMissingImportList
   | Opt_WarnMissingMethods
   | Opt_WarnMissingSigs
   | Opt_WarnMissingLocalSigs
   | Opt_WarnNameShadowing
   | Opt_WarnOverlappingPatterns
   | Opt_WarnTypeDefaults
   | Opt_WarnMonomorphism
   | Opt_WarnUnusedBinds
   | Opt_WarnUnusedImports
   | Opt_WarnUnusedMatches
   | Opt_WarnWarningsDeprecations
   | Opt_WarnDeprecatedFlags
   | Opt_WarnDodgyExports
   | Opt_WarnDodgyImports
   | Opt_WarnOrphans
   | Opt_WarnAutoOrphans
   | Opt_WarnIdentities
   | Opt_WarnTabs
   | Opt_WarnUnrecognisedPragmas
   | Opt_WarnDodgyForeignImports
   | Opt_WarnLazyUnliftedBindings
   | Opt_WarnUnusedDoBind
   | Opt_WarnWrongDoBind
   | Opt_WarnAlternativeLayoutRuleTransitional
   | Opt_WarnUnsafe
   | Opt_WarnSafe
   | Opt_WarnPointlessPragmas
   deriving (Eq, Show, Enum)

data Language = Haskell98 | Haskell2010
   deriving Enum

-- | The various Safe Haskell modes
data SafeHaskellMode
   = Sf_None
   | Sf_Unsafe
   | Sf_Trustworthy
   | Sf_Safe
   | Sf_SafeInfered
   deriving (Eq)

instance Outputable SafeHaskellMode where
    ppr Sf_None        = ptext $ sLit "None"
    ppr Sf_Unsafe      = ptext $ sLit "Unsafe"
    ppr Sf_Trustworthy = ptext $ sLit "Trustworthy"
    ppr Sf_Safe        = ptext $ sLit "Safe"
    ppr Sf_SafeInfered = ptext $ sLit "Safe-Infered"

data ExtensionFlag
   = Opt_Cpp
   | Opt_OverlappingInstances
   | Opt_UndecidableInstances
   | Opt_IncoherentInstances
   | Opt_MonomorphismRestriction
   | Opt_MonoPatBinds
   | Opt_MonoLocalBinds
   | Opt_RelaxedPolyRec           -- Deprecated
   | Opt_ExtendedDefaultRules     -- Use GHC's extended rules for defaulting
   | Opt_ForeignFunctionInterface
   | Opt_UnliftedFFITypes
   | Opt_InterruptibleFFI
   | Opt_CApiFFI
   | Opt_GHCForeignImportPrim
   | Opt_ParallelArrays           -- Syntactic support for parallel arrays
   | Opt_Arrows                   -- Arrow-notation syntax
   | Opt_TemplateHaskell
   | Opt_QuasiQuotes
   | Opt_ImplicitParams
   | Opt_ImplicitPrelude
   | Opt_ScopedTypeVariables
   | Opt_UnboxedTuples
   | Opt_BangPatterns
   | Opt_TypeFamilies
   | Opt_OverloadedStrings
   | Opt_DisambiguateRecordFields
   | Opt_RecordWildCards
   | Opt_RecordPuns
   | Opt_ViewPatterns
   | Opt_GADTs
   | Opt_GADTSyntax
   | Opt_NPlusKPatterns
   | Opt_DoAndIfThenElse
   | Opt_RebindableSyntax
   | Opt_ConstraintKinds
   | Opt_PolyKinds                -- Kind polymorphism
   | Opt_DataKinds                -- Datatype promotion
   | Opt_InstanceSigs
 
   | Opt_StandaloneDeriving
   | Opt_DeriveDataTypeable
   | Opt_DeriveFunctor
   | Opt_DeriveTraversable
   | Opt_DeriveFoldable
   | Opt_DeriveGeneric            -- Allow deriving Generic/1
   | Opt_DefaultSignatures        -- Allow extra signatures for defmeths

   | Opt_TypeSynonymInstances
   | Opt_FlexibleContexts
   | Opt_FlexibleInstances
   | Opt_ConstrainedClassMethods
   | Opt_MultiParamTypeClasses
   | Opt_FunctionalDependencies
   | Opt_UnicodeSyntax
   | Opt_PolymorphicComponents
   | Opt_ExistentialQuantification
   | Opt_MagicHash
   | Opt_EmptyDataDecls
   | Opt_KindSignatures
   | Opt_ParallelListComp
   | Opt_TransformListComp
   | Opt_MonadComprehensions
   | Opt_GeneralizedNewtypeDeriving
   | Opt_RecursiveDo
   | Opt_DoRec
   | Opt_PostfixOperators
   | Opt_TupleSections
   | Opt_PatternGuards
   | Opt_LiberalTypeSynonyms
   | Opt_Rank2Types
   | Opt_RankNTypes
   | Opt_ImpredicativeTypes
   | Opt_TypeOperators
   | Opt_ExplicitNamespaces
   | Opt_PackageImports
   | Opt_ExplicitForAll
   | Opt_AlternativeLayoutRule
   | Opt_AlternativeLayoutRuleTransitional
   | Opt_DatatypeContexts
   | Opt_NondecreasingIndentation
   | Opt_RelaxedLayout
   | Opt_TraditionalRecordSyntax
   deriving (Eq, Enum, Show)

-- | Contains not only a collection of 'DynFlag's but also a plethora of
-- information relating to the compilation of a single file or GHC session
data DynFlags = DynFlags {
  ghcMode               :: GhcMode,
  ghcLink               :: GhcLink,
  hscTarget             :: HscTarget,
  settings              :: Settings,
  hscOutName            :: String,      -- ^ Name of the output file
  extCoreName           :: String,      -- ^ Name of the .hcr output file
  verbosity             :: Int,         -- ^ Verbosity level: see Note [Verbosity levels]
  optLevel              :: Int,         -- ^ Optimisation level
  simplPhases           :: Int,         -- ^ Number of simplifier phases
  maxSimplIterations    :: Int,         -- ^ Max simplifier iterations
  shouldDumpSimplPhase  :: Maybe String,
  ruleCheck             :: Maybe String,
  strictnessBefore      :: [Int],       -- ^ Additional demand analysis

  simplTickFactor       :: Int,         -- ^ Multiplier for simplifier ticks
  specConstrThreshold   :: Maybe Int,   -- ^ Threshold for SpecConstr
  specConstrCount       :: Maybe Int,   -- ^ Max number of specialisations for any one function
  liberateCaseThreshold :: Maybe Int,   -- ^ Threshold for LiberateCase
  floatLamArgs          :: Maybe Int,   -- ^ Arg count for lambda floating
                                        --   See CoreMonad.FloatOutSwitches

  cmdlineHcIncludes     :: [String],    -- ^ @\-\#includes@
  importPaths           :: [FilePath],
  mainModIs             :: Module,
  mainFunIs             :: Maybe String,
  ctxtStkDepth          :: Int,         -- ^ Typechecker context stack depth

  thisPackage           :: PackageId,   -- ^ name of package currently being compiled

  -- ways
  ways                  :: [Way],       -- ^ Way flags from the command line
  buildTag              :: String,      -- ^ The global \"way\" (e.g. \"p\" for prof)
  rtsBuildTag           :: String,      -- ^ The RTS \"way\"

  -- For object splitting
  splitInfo             :: Maybe (String,Int),

  -- paths etc.
  objectDir             :: Maybe String,
  dylibInstallName      :: Maybe String,
  hiDir                 :: Maybe String,
  stubDir               :: Maybe String,
  dumpDir               :: Maybe String,

  objectSuf             :: String,
  hcSuf                 :: String,
  hiSuf                 :: String,

  outputFile            :: Maybe String,
  outputHi              :: Maybe String,
  dynLibLoader          :: DynLibLoader,

  -- | This is set by 'DriverPipeline.runPipeline' based on where
  --    its output is going.
  dumpPrefix            :: Maybe FilePath,

  -- | Override the 'dumpPrefix' set by 'DriverPipeline.runPipeline'.
  --    Set by @-ddump-file-prefix@
  dumpPrefixForce       :: Maybe FilePath,

  includePaths          :: [String],
  libraryPaths          :: [String],
  frameworkPaths        :: [String],    -- used on darwin only
  cmdlineFrameworks     :: [String],    -- ditto

  rtsOpts               :: Maybe String,
  rtsOptsEnabled        :: RtsOptsEnabled,

  hpcDir                :: String,      -- ^ Path to store the .mix files

  -- Plugins
  pluginModNames        :: [ModuleName],
  pluginModNameOpts     :: [(ModuleName,String)],

  --  For ghc -M
  depMakefile           :: FilePath,
  depIncludePkgDeps     :: Bool,
  depExcludeMods        :: [ModuleName],
  depSuffixes           :: [String],

  --  Package flags
  extraPkgConfs         :: [FilePath],
        -- ^ The @-package-conf@ flags given on the command line, in the order
        -- they appeared.

  packageFlags          :: [PackageFlag],
        -- ^ The @-package@ and @-hide-package@ flags from the command-line

  -- Package state
  -- NB. do not modify this field, it is calculated by
  -- Packages.initPackages and Packages.updatePackages.
  pkgDatabase           :: Maybe [PackageConfig],
  pkgState              :: PackageState,

  -- Temporary files
  -- These have to be IORefs, because the defaultCleanupHandler needs to
  -- know what to clean when an exception happens
  filesToClean          :: IORef [FilePath],
  dirsToClean           :: IORef (Map FilePath FilePath),

  -- Names of files which were generated from -ddump-to-file; used to
  -- track which ones we need to truncate because it's our first run
  -- through
  generatedDumps        :: IORef (Set FilePath),

  -- hsc dynamic flags
  flags                 :: IntSet,
  warningFlags          :: IntSet,
  -- Don't change this without updating extensionFlags:
  language              :: Maybe Language,
  -- | Safe Haskell mode
  safeHaskell           :: SafeHaskellMode,
  -- We store the location of where some extension and flags were turned on so
  -- we can produce accurate error messages when Safe Haskell fails due to
  -- them.
  thOnLoc               :: SrcSpan,
  newDerivOnLoc         :: SrcSpan,
  pkgTrustOnLoc         :: SrcSpan,
  warnSafeOnLoc         :: SrcSpan,
  warnUnsafeOnLoc       :: SrcSpan,
  -- Don't change this without updating extensionFlags:
  extensions            :: [OnOff ExtensionFlag],
  -- extensionFlags should always be equal to
  --     flattenExtensionFlags language extensions
  extensionFlags        :: IntSet,

  -- | MsgDoc output action: use "ErrUtils" instead of this if you can
  log_action            :: LogAction,
  flushOut              :: FlushOut,
  flushErr              :: FlushErr,

  haddockOptions        :: Maybe String,

  -- | what kind of {-# SCC #-} to add automatically
  profAuto              :: ProfAuto,

  llvmVersion           :: IORef (Int)
 }

class HasDynFlags m where
    getDynFlags :: m DynFlags

class ContainsDynFlags t where
    extractDynFlags :: t -> DynFlags

data ProfAuto
  = NoProfAuto         -- ^ no SCC annotations added
  | ProfAutoAll        -- ^ top-level and nested functions are annotated
  | ProfAutoTop        -- ^ top-level functions annotated only
  | ProfAutoExports    -- ^ exported functions annotated only
  | ProfAutoCalls      -- ^ annotate call-sites
  deriving (Enum)

data Settings = Settings {
  sTargetPlatform        :: Platform,    -- Filled in by SysTools
  sGhcUsagePath          :: FilePath,    -- Filled in by SysTools
  sGhciUsagePath         :: FilePath,    -- ditto
  sTopDir                :: FilePath,
  sTmpDir                :: String,      -- no trailing '/'
  -- You shouldn't need to look things up in rawSettings directly.
  -- They should have their own fields instead.
  sRawSettings           :: [(String, String)],
  sExtraGccViaCFlags     :: [String],
  sSystemPackageConfig   :: FilePath,
  -- commands for particular phases
  sPgm_L                 :: String,
  sPgm_P                 :: (String,[Option]),
  sPgm_F                 :: String,
  sPgm_c                 :: (String,[Option]),
  sPgm_s                 :: (String,[Option]),
  sPgm_a                 :: (String,[Option]),
  sPgm_l                 :: (String,[Option]),
  sPgm_dll               :: (String,[Option]),
  sPgm_T                 :: String,
  sPgm_sysman            :: String,
  sPgm_windres           :: String,
  sPgm_lo                :: (String,[Option]), -- LLVM: opt llvm optimiser
  sPgm_lc                :: (String,[Option]), -- LLVM: llc static compiler
  -- options for particular phases
  sOpt_L                 :: [String],
  sOpt_P                 :: [String],
  sOpt_F                 :: [String],
  sOpt_c                 :: [String],
  sOpt_a                 :: [String],
  sOpt_l                 :: [String],
  sOpt_windres           :: [String],
  sOpt_lo                :: [String], -- LLVM: llvm optimiser
  sOpt_lc                :: [String]  -- LLVM: llc static compiler

 }

targetPlatform :: DynFlags -> Platform
targetPlatform dflags = sTargetPlatform (settings dflags)

ghcUsagePath          :: DynFlags -> FilePath
ghcUsagePath dflags = sGhcUsagePath (settings dflags)
ghciUsagePath         :: DynFlags -> FilePath
ghciUsagePath dflags = sGhciUsagePath (settings dflags)
topDir                :: DynFlags -> FilePath
topDir dflags = sTopDir (settings dflags)
tmpDir                :: DynFlags -> String
tmpDir dflags = sTmpDir (settings dflags)
rawSettings           :: DynFlags -> [(String, String)]
rawSettings dflags = sRawSettings (settings dflags)
extraGccViaCFlags     :: DynFlags -> [String]
extraGccViaCFlags dflags = sExtraGccViaCFlags (settings dflags)
systemPackageConfig   :: DynFlags -> FilePath
systemPackageConfig dflags = sSystemPackageConfig (settings dflags)
pgm_L                 :: DynFlags -> String
pgm_L dflags = sPgm_L (settings dflags)
pgm_P                 :: DynFlags -> (String,[Option])
pgm_P dflags = sPgm_P (settings dflags)
pgm_F                 :: DynFlags -> String
pgm_F dflags = sPgm_F (settings dflags)
pgm_c                 :: DynFlags -> (String,[Option])
pgm_c dflags = sPgm_c (settings dflags)
pgm_s                 :: DynFlags -> (String,[Option])
pgm_s dflags = sPgm_s (settings dflags)
pgm_a                 :: DynFlags -> (String,[Option])
pgm_a dflags = sPgm_a (settings dflags)
pgm_l                 :: DynFlags -> (String,[Option])
pgm_l dflags = sPgm_l (settings dflags)
pgm_dll               :: DynFlags -> (String,[Option])
pgm_dll dflags = sPgm_dll (settings dflags)
pgm_T                 :: DynFlags -> String
pgm_T dflags = sPgm_T (settings dflags)
pgm_sysman            :: DynFlags -> String
pgm_sysman dflags = sPgm_sysman (settings dflags)
pgm_windres           :: DynFlags -> String
pgm_windres dflags = sPgm_windres (settings dflags)
pgm_lo                :: DynFlags -> (String,[Option])
pgm_lo dflags = sPgm_lo (settings dflags)
pgm_lc                :: DynFlags -> (String,[Option])
pgm_lc dflags = sPgm_lc (settings dflags)
opt_L                 :: DynFlags -> [String]
opt_L dflags = sOpt_L (settings dflags)
opt_P                 :: DynFlags -> [String]
opt_P dflags = sOpt_P (settings dflags)
opt_F                 :: DynFlags -> [String]
opt_F dflags = sOpt_F (settings dflags)
opt_c                 :: DynFlags -> [String]
opt_c dflags = sOpt_c (settings dflags)
opt_a                 :: DynFlags -> [String]
opt_a dflags = sOpt_a (settings dflags)
opt_l                 :: DynFlags -> [String]
opt_l dflags = sOpt_l (settings dflags)
opt_windres           :: DynFlags -> [String]
opt_windres dflags = sOpt_windres (settings dflags)
opt_lo                :: DynFlags -> [String]
opt_lo dflags = sOpt_lo (settings dflags)
opt_lc                :: DynFlags -> [String]
opt_lc dflags = sOpt_lc (settings dflags)

wayNames :: DynFlags -> [WayName]
wayNames = map wayName . ways

-- | The target code type of the compilation (if any).
--
-- Whenever you change the target, also make sure to set 'ghcLink' to
-- something sensible.
--
-- 'HscNothing' can be used to avoid generating any output, however, note
-- that:
--
--  * This will not run the desugaring step, thus no warnings generated in
--    this step will be output.  In particular, this includes warnings related
--    to pattern matching.  You can run the desugarer manually using
--    'GHC.desugarModule'.
--
--  * If a program uses Template Haskell the typechecker may try to run code
--    from an imported module.  This will fail if no code has been generated
--    for this module.  You can use 'GHC.needsTemplateHaskell' to detect
--    whether this might be the case and choose to either switch to a
--    different target or avoid typechecking such modules.  (The latter may be
--    preferable for security reasons.)
--
data HscTarget
  = HscC           -- ^ Generate C code.
  | HscAsm         -- ^ Generate assembly using the native code generator.
  | HscLlvm        -- ^ Generate assembly using the llvm code generator.
  | HscInterpreted -- ^ Generate bytecode.  (Requires 'LinkInMemory')
  | HscNothing     -- ^ Don't generate any code.  See notes above.
  deriving (Eq, Show)

showHscTargetFlag :: HscTarget -> String
showHscTargetFlag HscC           = "-fvia-c"
showHscTargetFlag HscAsm         = "-fasm"
showHscTargetFlag HscLlvm        = "-fllvm"
showHscTargetFlag HscInterpreted = "-fbyte-code"
showHscTargetFlag HscNothing     = "-fno-code"

-- | Will this target result in an object file on the disk?
isObjectTarget :: HscTarget -> Bool
isObjectTarget HscC     = True
isObjectTarget HscAsm   = True
isObjectTarget HscLlvm  = True
isObjectTarget _        = False

-- | Does this target retain *all* top-level bindings for a module,
-- rather than just the exported bindings, in the TypeEnv and compiled
-- code (if any)?  In interpreted mode we do this, so that GHCi can
-- call functions inside a module.  In HscNothing mode we also do it,
-- so that Haddock can get access to the GlobalRdrEnv for a module
-- after typechecking it.
targetRetainsAllBindings :: HscTarget -> Bool
targetRetainsAllBindings HscInterpreted = True
targetRetainsAllBindings HscNothing     = True
targetRetainsAllBindings _              = False

-- | The 'GhcMode' tells us whether we're doing multi-module
-- compilation (controlled via the "GHC" API) or one-shot
-- (single-module) compilation.  This makes a difference primarily to
-- the "Finder": in one-shot mode we look for interface files for
-- imported modules, but in multi-module mode we look for source files
-- in order to check whether they need to be recompiled.
data GhcMode
  = CompManager         -- ^ @\-\-make@, GHCi, etc.
  | OneShot             -- ^ @ghc -c Foo.hs@
  | MkDepend            -- ^ @ghc -M@, see "Finder" for why we need this
  deriving Eq

instance Outputable GhcMode where
  ppr CompManager = ptext (sLit "CompManager")
  ppr OneShot     = ptext (sLit "OneShot")
  ppr MkDepend    = ptext (sLit "MkDepend")

isOneShot :: GhcMode -> Bool
isOneShot OneShot = True
isOneShot _other  = False

-- | What to do in the link step, if there is one.
data GhcLink
  = NoLink              -- ^ Don't link at all
  | LinkBinary          -- ^ Link object code into a binary
  | LinkInMemory        -- ^ Use the in-memory dynamic linker (works for both
                        --   bytecode and object code).
  | LinkDynLib          -- ^ Link objects into a dynamic lib (DLL on Windows, DSO on ELF platforms)
  deriving (Eq, Show)

isNoLink :: GhcLink -> Bool
isNoLink NoLink = True
isNoLink _      = False

-- Is it worth evaluating this Bool and caching it in the DynFlags value
-- during initDynFlags?
doingTickyProfiling :: DynFlags -> Bool
doingTickyProfiling _ = opt_Ticky
  -- XXX -ticky is a static flag, because it implies -debug which is also
  -- static.  If the way flags were made dynamic, we could fix this.

data PackageFlag
  = ExposePackage   String
  | ExposePackageId String
  | HidePackage     String
  | IgnorePackage   String
  | TrustPackage    String
  | DistrustPackage String
  deriving Eq

defaultHscTarget :: HscTarget
defaultHscTarget = defaultObjectTarget

-- | The 'HscTarget' value corresponding to the default way to create
-- object files on the current platform.
defaultObjectTarget :: HscTarget
defaultObjectTarget
  | cGhcUnregisterised    == "YES"      =  HscC
  | cGhcWithNativeCodeGen == "YES"      =  HscAsm
  | otherwise                           =  HscLlvm

data DynLibLoader
  = Deployable
  | SystemDependent
  deriving Eq

data RtsOptsEnabled = RtsOptsNone | RtsOptsSafeOnly | RtsOptsAll
  deriving (Show)

-- | Used by 'GHC.newSession' to partially initialize a new 'DynFlags' value
initDynFlags :: DynFlags -> IO DynFlags
initDynFlags dflags = do
 -- someday these will be dynamic flags
 ways <- readIORef v_Ways
 refFilesToClean <- newIORef []
 refDirsToClean <- newIORef Map.empty
 refGeneratedDumps <- newIORef Set.empty
 refLlvmVersion <- newIORef 28
 return dflags{
        ways           = ways,
        buildTag       = mkBuildTag (filter (not . wayRTSOnly) ways),
        rtsBuildTag    = mkBuildTag ways,
        filesToClean   = refFilesToClean,
        dirsToClean    = refDirsToClean,
        generatedDumps = refGeneratedDumps,
        llvmVersion    = refLlvmVersion
        }

-- | The normal 'DynFlags'. Note that they is not suitable for use in this form
-- and must be fully initialized by 'GHC.newSession' first.
defaultDynFlags :: Settings -> DynFlags
defaultDynFlags mySettings =
     DynFlags {
        ghcMode                 = CompManager,
        ghcLink                 = LinkBinary,
        hscTarget               = defaultHscTarget,
        hscOutName              = "",
        extCoreName             = "",
        verbosity               = 0,
        optLevel                = 0,
        simplPhases             = 2,
        maxSimplIterations      = 4,
        shouldDumpSimplPhase    = Nothing,
        ruleCheck               = Nothing,
        simplTickFactor         = 100,
        specConstrThreshold     = Just 2000,
        specConstrCount         = Just 3,
        liberateCaseThreshold   = Just 2000,
        floatLamArgs            = Just 0, -- Default: float only if no fvs
        strictnessBefore        = [],

        cmdlineHcIncludes       = [],
        importPaths             = ["."],
        mainModIs               = mAIN,
        mainFunIs               = Nothing,
        ctxtStkDepth            = mAX_CONTEXT_REDUCTION_DEPTH,

        thisPackage             = mainPackageId,

        objectDir               = Nothing,
        dylibInstallName        = Nothing,
        hiDir                   = Nothing,
        stubDir                 = Nothing,
        dumpDir                 = Nothing,

        objectSuf               = phaseInputExt StopLn,
        hcSuf                   = phaseInputExt HCc,
        hiSuf                   = "hi",

        pluginModNames          = [],
        pluginModNameOpts       = [],

        outputFile              = Nothing,
        outputHi                = Nothing,
        dynLibLoader            = SystemDependent,
        dumpPrefix              = Nothing,
        dumpPrefixForce         = Nothing,
        includePaths            = [],
        libraryPaths            = [],
        frameworkPaths          = [],
        cmdlineFrameworks       = [],
        rtsOpts                 = Nothing,
        rtsOptsEnabled          = RtsOptsSafeOnly,

        hpcDir                  = ".hpc",

        extraPkgConfs           = [],
        packageFlags            = [],
        pkgDatabase             = Nothing,
        pkgState                = panic "no package state yet: call GHC.setSessionDynFlags",
        ways                    = panic "defaultDynFlags: No ways",
        buildTag                = panic "defaultDynFlags: No buildTag",
        rtsBuildTag             = panic "defaultDynFlags: No rtsBuildTag",
        splitInfo               = Nothing,
        settings                = mySettings,
        -- ghc -M values
        depMakefile       = "Makefile",
        depIncludePkgDeps = False,
        depExcludeMods    = [],
        depSuffixes       = [],
        -- end of ghc -M values
        filesToClean   = panic "defaultDynFlags: No filesToClean",
        dirsToClean    = panic "defaultDynFlags: No dirsToClean",
        generatedDumps = panic "defaultDynFlags: No generatedDumps",
        haddockOptions = Nothing,
        flags = IntSet.fromList (map fromEnum defaultFlags),
        warningFlags = IntSet.fromList (map fromEnum standardWarnings),
        language = Nothing,
        safeHaskell = Sf_SafeInfered,
        thOnLoc = noSrcSpan,
        newDerivOnLoc = noSrcSpan,
        pkgTrustOnLoc = noSrcSpan,
        warnSafeOnLoc = noSrcSpan,
        warnUnsafeOnLoc = noSrcSpan,
        extensions = [],
        extensionFlags = flattenExtensionFlags Nothing [],
        log_action = defaultLogAction,
        flushOut = defaultFlushOut,
        flushErr = defaultFlushErr,
        profAuto = NoProfAuto,
        llvmVersion = panic "defaultDynFlags: No llvmVersion"
      }

type LogAction = Severity -> SrcSpan -> PprStyle -> MsgDoc -> IO ()