{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleInstances #-}

-------------------------------------------------------------------------------
--
-- | 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
--
-------------------------------------------------------------------------------

{-# OPTIONS_GHC -fno-cse #-}
-- -fno-cse is needed for GLOBAL_VAR's to behave properly

module DynFlags (
        -- * Dynamic flags and associated configuration types
        DumpFlag(..),
        GeneralFlag(..),
        WarningFlag(..), WarnReason(..),
        Language(..),
        PlatformConstants(..),
        FatalMessager, LogAction, FlushOut(..), FlushErr(..),
        ProfAuto(..),
        glasgowExtsFlags,
        warningGroups, warningHierarchies,
        hasPprDebug, hasNoDebugOutput, hasNoStateHack, hasNoOptCoercion,
        dopt, dopt_set, dopt_unset,
        gopt, gopt_set, gopt_unset, setGeneralFlag', unSetGeneralFlag',
        wopt, wopt_set, wopt_unset,
        wopt_fatal, wopt_set_fatal, wopt_unset_fatal,
        xopt, xopt_set, xopt_unset,
        xopt_set_unlessExplSpec,
        lang_set,
        useUnicodeSyntax,
        useStarIsType,
        whenGeneratingDynamicToo, ifGeneratingDynamicToo,
        whenCannotGenerateDynamicToo,
        dynamicTooMkDynamicDynFlags,
        dynamicOutputFile,
        DynFlags(..),
        FlagSpec(..),
        HasDynFlags(..), ContainsDynFlags(..),
        RtsOptsEnabled(..),
        HscTarget(..), isObjectTarget, defaultObjectTarget,
        targetRetainsAllBindings,
        GhcMode(..), isOneShot,
        GhcLink(..), isNoLink,
        PackageFlag(..), PackageArg(..), ModRenaming(..),
        packageFlagsChanged,
        IgnorePackageFlag(..), TrustFlag(..),
        PackageDBFlag(..), PkgConfRef(..),
        Option(..), showOpt,
        DynLibLoader(..),
        fFlags, fLangFlags, xFlags,
        wWarningFlags,
        dynFlagDependencies,
        tablesNextToCode,
        makeDynFlagsConsistent,
        shouldUseColor,
        shouldUseHexWordLiterals,
        positionIndependent,
        optimisationFlags,

        Way(..), mkBuildTag, wayRTSOnly, addWay', updateWays,
        wayGeneralFlags, wayUnsetGeneralFlags,

        thisPackage, thisComponentId, thisUnitIdInsts,

        -- ** Log output
        putLogMsg,

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

        -- ** LLVM Targets
        LlvmTarget(..), LlvmTargets, LlvmPasses, LlvmConfig,

        -- ** System tool settings and locations
        Settings(..),
        IntegerLibrary(..),
        targetPlatform, programName, projectVersion,
        ghcUsagePath, ghciUsagePath, topDir, tmpDir, rawSettings,
        versionedAppDir,
        extraGccViaCFlags, systemPackageConfig,
        pgm_L, pgm_P, pgm_F, pgm_c, pgm_a, pgm_l, pgm_dll, pgm_T,
        pgm_windres, pgm_libtool, pgm_ar, pgm_ranlib, pgm_lo, pgm_lc,
        pgm_lcc, pgm_i,
        opt_L, opt_P, opt_F, opt_c, opt_cxx, opt_a, opt_l, opt_i,
        opt_P_signature,
        opt_windres, opt_lo, opt_lc, opt_lcc,

        -- ** Manipulating DynFlags
        addPluginModuleName,
        defaultDynFlags,                -- Settings -> DynFlags
        defaultWays,
        interpWays,
        interpreterProfiled, interpreterDynamic,
        initDynFlags,                   -- DynFlags -> IO DynFlags
        defaultFatalMessager,
        defaultLogAction,
        defaultLogActionHPrintDoc,
        defaultLogActionHPutStrDoc,
        defaultFlushOut,
        defaultFlushErr,

        getOpts,                        -- DynFlags -> (DynFlags -> [a]) -> [a]
        getVerbFlags,
        updOptLevel,
        setTmpDir,
        setUnitId,
        interpretPackageEnv,
        canonicalizeHomeModule,
        canonicalizeModuleIfHome,

        -- ** Parsing DynFlags
        parseDynamicFlagsCmdLine,
        parseDynamicFilePragma,
        parseDynamicFlagsFull,

        -- ** Available DynFlags
        allNonDeprecatedFlags,
        flagsAll,
        flagsDynamic,
        flagsPackage,
        flagsForCompletion,

        supportedLanguagesAndExtensions,
        languageExtensions,

        -- ** DynFlags C compiler options
        picCCOpts, picPOpts,

        -- * Compiler configuration suitable for display to the user
        compilerInfo,

        rtsIsProfiled,
        dynamicGhc,

#include "GHCConstantsHaskellExports.hs"
        bLOCK_SIZE_W,
        wORD_SIZE_IN_BITS,
        wordAlignment,
        tAG_MASK,
        mAX_PTR_TAG,
        tARGET_MIN_INT, tARGET_MAX_INT, tARGET_MAX_WORD,

        unsafeGlobalDynFlags, setUnsafeGlobalDynFlags,

        -- * SSE and AVX
        isSseEnabled,
        isSse2Enabled,
        isSse4_2Enabled,
        isBmiEnabled,
        isBmi2Enabled,
        isAvxEnabled,
        isAvx2Enabled,
        isAvx512cdEnabled,
        isAvx512erEnabled,
        isAvx512fEnabled,
        isAvx512pfEnabled,

        -- * Linker/compiler information
        LinkerInfo(..),
        CompilerInfo(..),

        -- * File cleanup
        FilesToClean(..), emptyFilesToClean,

        -- * Include specifications
        IncludeSpecs(..), addGlobalInclude, addQuoteInclude, flattenIncludes,


        -- * Make use of the Cmm CFG
        CfgWeights(..), backendMaintainsCfg
  ) where

#include "HsVersions.h"

import GhcPrelude

import Platform
import PlatformConstants
import Module
import PackageConfig
import {-# SOURCE #-} Plugins
import {-# SOURCE #-} Hooks
import {-# SOURCE #-} PrelNames ( mAIN )
import {-# SOURCE #-} Packages (PackageState, emptyPackageState)
import DriverPhases     ( Phase(..), phaseInputExt )
import Config
import CmdLineParser hiding (WarnReason(..))
import qualified CmdLineParser as Cmd
import Constants
import Panic
import qualified PprColour as Col
import Util
import Maybes
import MonadUtils
import qualified Pretty
import SrcLoc
import BasicTypes       ( Alignment, alignmentOf, IntWithInf, treatZeroAsInf )
import FastString
import Fingerprint
import Outputable
import Foreign.C        ( CInt(..) )
import System.IO.Unsafe ( unsafeDupablePerformIO )
import {-# SOURCE #-} ErrUtils ( Severity(..), MsgDoc, mkLocMessageAnn
                               , getCaretDiagnostic )
import Json
import SysTools.Terminal ( stderrSupportsAnsiColors )
import SysTools.BaseDir ( expandToolDir, expandTopDir )

import System.IO.Unsafe ( unsafePerformIO )
import Data.IORef
import Control.Arrow ((&&&))
import Control.Monad
import Control.Monad.Trans.Class
import Control.Monad.Trans.Writer
import Control.Monad.Trans.Reader
import Control.Monad.Trans.Except
import Control.Exception (throwIO)

import Data.Ord
import Data.Bits
import Data.Char
import Data.Int
import Data.List
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Set (Set)
import qualified Data.Set as Set
import Data.Word
import System.FilePath
import System.Directory
import System.Environment (getEnv, lookupEnv)
import System.IO
import System.IO.Error
import Text.ParserCombinators.ReadP hiding (char)
import Text.ParserCombinators.ReadP as R

import EnumSet (EnumSet)
import qualified EnumSet

import GHC.Foreign (withCString, peekCString)
import qualified GHC.LanguageExtensions as LangExt

#if defined(GHCI)
import Foreign (Ptr) -- needed for 2nd stage
#endif

-- Note [Updating flag description in the User's Guide]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
-- If you modify anything in this file please make sure that your changes are
-- described in the User's Guide. Please update the flag description in the
-- users guide (docs/users_guide) whenever you add or change a flag.

-- Note [Supporting CLI completion]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
-- The command line interface completion (in for example bash) is an easy way
-- for the developer to learn what flags are available from GHC.
-- GHC helps by separating which flags are available when compiling with GHC,
-- and which flags are available when using GHCi.
-- A flag is assumed to either work in both these modes, or only in one of them.
-- When adding or changing a flag, please consider for which mode the flag will
-- have effect, and annotate it accordingly. For Flags use defFlag, defGhcFlag,
-- defGhciFlag, and for FlagSpec use flagSpec or flagGhciSpec.

-- Note [Adding a language extension]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
-- There are a few steps to adding (or removing) a language extension,
--
--  * Adding the extension to GHC.LanguageExtensions
--
--    The Extension type in libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
--    is the canonical list of language extensions known by GHC.
--
--  * Adding a flag to DynFlags.xFlags
--
--    This is fairly self-explanatory. The name should be concise, memorable,
--    and consistent with any previous implementations of the similar idea in
--    other Haskell compilers.
--
--  * Adding the flag to the documentation
--
--    This is the same as any other flag. See
--    Note [Updating flag description in the User's Guide]
--
--  * Adding the flag to Cabal
--
--    The Cabal library has its own list of all language extensions supported
--    by all major compilers. This is the list that user code being uploaded
--    to Hackage is checked against to ensure language extension validity.
--    Consequently, it is very important that this list remains up-to-date.
--
--    To this end, there is a testsuite test (testsuite/tests/driver/T4437.hs)
--    whose job it is to ensure these GHC's extensions are consistent with
--    Cabal.
--
--    The recommended workflow is,
--
--     1. Temporarily add your new language extension to the
--        expectedGhcOnlyExtensions list in T4437 to ensure the test doesn't
--        break while Cabal is updated.
--
--     2. After your GHC change is accepted, submit a Cabal pull request adding
--        your new extension to Cabal's list (found in
--        Cabal/Language/Haskell/Extension.hs).
--
--     3. After your Cabal change is accepted, let the GHC developers know so
--        they can update the Cabal submodule and remove the extensions from
--        expectedGhcOnlyExtensions.
--
--  * Adding the flag to the GHC Wiki
--
--    There is a change log tracking language extension additions and removals
--    on the GHC wiki:  https://gitlab.haskell.org/ghc/ghc/wikis/language-pragma-history
--
--  See #4437 and #8176.

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

data DumpFlag
-- See Note [Updating flag description in the User's Guide]

   -- debugging flags
   = Opt_D_dump_cmm
   | Opt_D_dump_cmm_from_stg
   | Opt_D_dump_cmm_raw
   | Opt_D_dump_cmm_verbose
   -- All of the cmm subflags (there are a lot!) automatically
   -- enabled if you run -ddump-cmm-verbose
   -- Each flag corresponds to exact stage of Cmm pipeline.
   | Opt_D_dump_cmm_cfg
   | Opt_D_dump_cmm_cbe
   | Opt_D_dump_cmm_switch
   | Opt_D_dump_cmm_proc
   | Opt_D_dump_cmm_sp
   | Opt_D_dump_cmm_sink
   | Opt_D_dump_cmm_caf
   | Opt_D_dump_cmm_procmap
   | Opt_D_dump_cmm_split
   | Opt_D_dump_cmm_info
   | Opt_D_dump_cmm_cps
   -- end cmm subflags
   | Opt_D_dump_cfg_weights -- ^ Dump the cfg used for block layout.
   | Opt_D_dump_asm
   | Opt_D_dump_asm_native
   | Opt_D_dump_asm_liveness
   | 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_deriv
   | Opt_D_dump_ds
   | Opt_D_dump_ds_preopt
   | Opt_D_dump_foreign
   | Opt_D_dump_inlinings
   | Opt_D_dump_rule_firings
   | Opt_D_dump_rule_rewrites
   | Opt_D_dump_simpl_trace
   | Opt_D_dump_occur_anal
   | Opt_D_dump_parsed
   | Opt_D_dump_parsed_ast
   | Opt_D_dump_rn
   | Opt_D_dump_rn_ast
   | Opt_D_dump_shape
   | Opt_D_dump_simpl
   | Opt_D_dump_simpl_iterations
   | Opt_D_dump_spec
   | Opt_D_dump_prep
   | Opt_D_dump_stg
   | Opt_D_dump_stg_final
   | Opt_D_dump_call_arity
   | Opt_D_dump_exitify
   | Opt_D_dump_stranal
   | Opt_D_dump_str_signatures
   | Opt_D_dump_tc
   | Opt_D_dump_tc_ast
   | 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_ec_trace -- Pattern match exhaustiveness checker
   | Opt_D_dump_if_trace
   | Opt_D_dump_vt_trace
   | Opt_D_dump_splices
   | Opt_D_th_dec_file
   | Opt_D_dump_BCOs
   | Opt_D_dump_ticked
   | Opt_D_dump_rtti
   | Opt_D_source_stats
   | Opt_D_verbose_stg2stg
   | Opt_D_dump_hi
   | Opt_D_dump_hi_diffs
   | Opt_D_dump_mod_cycles
   | Opt_D_dump_mod_map
   | Opt_D_dump_timings
   | Opt_D_dump_view_pattern_commoning
   | Opt_D_verbose_core2core
   | Opt_D_dump_debug
   | Opt_D_dump_json
   | Opt_D_ppr_debug
   | Opt_D_no_debug_output
   deriving (Eq, Show, Enum)


-- | Enumerates the simple on-or-off dynamic flags
data GeneralFlag
-- See Note [Updating flag description in the User's Guide]

   = Opt_DumpToFile                     -- ^ Append dump output to files instead of stdout.
   | Opt_D_faststring_stats
   | Opt_D_dump_minimal_imports
   | Opt_DoCoreLinting
   | Opt_DoStgLinting
   | Opt_DoCmmLinting
   | Opt_DoAsmLinting
   | Opt_DoAnnotationLinting
   | Opt_NoLlvmMangler                 -- hidden flag
   | Opt_FastLlvm                      -- hidden flag

   | Opt_WarnIsError                    -- -Werror; makes warnings fatal
   | Opt_ShowWarnGroups                 -- Show the group a warning belongs to
   | Opt_HideSourcePaths                -- Hide module source/object paths

   | Opt_PrintExplicitForalls
   | Opt_PrintExplicitKinds
   | Opt_PrintExplicitCoercions
   | Opt_PrintExplicitRuntimeReps
   | Opt_PrintEqualityRelations
   | Opt_PrintUnicodeSyntax
   | Opt_PrintExpandedSynonyms
   | Opt_PrintPotentialInstances
   | Opt_PrintTypecheckerElaboration

   -- optimisation opts
   | Opt_CallArity
   | Opt_Exitification
   | Opt_Strictness
   | Opt_LateDmdAnal                    -- #6087
   | Opt_KillAbsence
   | Opt_KillOneShot
   | Opt_FullLaziness
   | Opt_FloatIn
   | Opt_LateSpecialise
   | Opt_Specialise
   | Opt_SpecialiseAggressively
   | Opt_CrossModuleSpecialise
   | Opt_StaticArgumentTransformation
   | Opt_CSE
   | Opt_StgCSE
   | Opt_StgLiftLams
   | Opt_LiberateCase
   | Opt_SpecConstr
   | Opt_SpecConstrKeen
   | Opt_DoLambdaEtaExpansion
   | Opt_IgnoreAsserts
   | Opt_DoEtaReduction
   | Opt_CaseMerge
   | Opt_CaseFolding                    -- Constant folding through case-expressions
   | Opt_UnboxStrictFields
   | Opt_UnboxSmallStrictFields
   | Opt_DictsCheap
   | Opt_EnableRewriteRules             -- Apply rewrite rules during simplification
   | 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_LlvmFillUndefWithGarbage       -- Testing for undef bugs (hidden flag)
   | Opt_IrrefutableTuples
   | Opt_CmmSink
   | Opt_CmmElimCommonBlocks
   | Opt_AsmShortcutting
   | Opt_OmitYields
   | Opt_FunToThunk               -- allow WwLib.mkWorkerArgs to remove all value lambdas
   | Opt_DictsStrict                     -- be strict in argument dictionaries
   | Opt_DmdTxDictSel              -- use a special demand transformer for dictionary selectors
   | Opt_Loopification                  -- See Note [Self-recursive tail calls]
   | Opt_CfgBlocklayout             -- ^ Use the cfg based block layout algorithm.
   | Opt_WeightlessBlocklayout         -- ^ Layout based on last instruction per block.
   | Opt_CprAnal
   | Opt_WorkerWrapper
   | Opt_SolveConstantDicts
   | Opt_AlignmentSanitisation
   | Opt_CatchBottoms
   | Opt_NumConstantFolding

   -- PreInlining is on by default. The option is there just to see how
   -- bad things get if you turn it off!
   | Opt_SimplPreInlining

   -- Interface files
   | Opt_IgnoreInterfacePragmas
   | Opt_OmitInterfacePragmas
   | Opt_ExposeAllUnfoldings
   | Opt_WriteInterface -- forces .hi files to be written even with -fno-code
   | Opt_WriteHie -- generate .hie files

   -- profiling opts
   | Opt_AutoSccsOnIndividualCafs
   | Opt_ProfCountEntries

   -- misc opts
   | Opt_Pp
   | Opt_ForceRecomp
   | Opt_IgnoreOptimChanges
   | Opt_IgnoreHpcChanges
   | Opt_ExcessPrecision
   | Opt_EagerBlackHoling
   | Opt_NoHsMain
   | Opt_SplitSections
   | Opt_StgStats
   | Opt_HideAllPackages
   | Opt_HideAllPluginPackages
   | Opt_PrintBindResult
   | Opt_Haddock
   | Opt_HaddockOptions
   | Opt_BreakOnException
   | Opt_BreakOnError
   | Opt_PrintEvldWithShow
   | Opt_PrintBindContents
   | Opt_GenManifest
   | Opt_EmbedManifest
   | Opt_SharedImplib
   | Opt_BuildingCabalPackage
   | Opt_IgnoreDotGhci
   | Opt_GhciSandbox
   | Opt_GhciHistory
   | Opt_GhciLeakCheck
   | Opt_ValidateHie
   | Opt_LocalGhciHistory
   | Opt_NoIt
   | Opt_HelpfulErrors
   | Opt_DeferTypeErrors
   | Opt_DeferTypedHoles
   | Opt_DeferOutOfScopeVariables
   | Opt_PIC                         -- ^ @-fPIC@
   | Opt_PIE                         -- ^ @-fPIE@
   | Opt_PICExecutable               -- ^ @-pie@
   | Opt_ExternalDynamicRefs
   | Opt_SccProfilingOn
   | Opt_Ticky
   | Opt_Ticky_Allocd
   | Opt_Ticky_LNE
   | Opt_Ticky_Dyn_Thunk
   | Opt_RPath
   | Opt_RelativeDynlibPaths
   | Opt_Hpc
   | Opt_FlatCache
   | Opt_ExternalInterpreter
   | Opt_OptimalApplicativeDo
   | Opt_VersionMacros
   | Opt_WholeArchiveHsLibs
   -- copy all libs into a single folder prior to linking binaries
   -- this should elivate the excessive command line limit restrictions
   -- on windows, by only requiring a single -L argument instead of
   -- one for each dependency.  At the time of this writing, gcc
   -- forwards all -L flags to the collect2 command without using a
   -- response file and as such breaking apart.
   | Opt_SingleLibFolder
   | Opt_KeepCAFs

   -- output style opts
   | Opt_ErrorSpans -- Include full span info in error messages,
                    -- instead of just the start position.
   | Opt_DeferDiagnostics
   | Opt_DiagnosticsShowCaret -- Show snippets of offending code
   | Opt_PprCaseAsLet
   | Opt_PprShowTicks
   | Opt_ShowHoleConstraints
    -- Options relating to the display of valid hole fits
    -- when generating an error message for a typed hole
    -- See Note [Valid hole fits include] in TcHoleErrors.hs
   | Opt_ShowValidHoleFits
   | Opt_SortValidHoleFits
   | Opt_SortBySizeHoleFits
   | Opt_SortBySubsumHoleFits
   | Opt_AbstractRefHoleFits
   | Opt_UnclutterValidHoleFits
   | Opt_ShowTypeAppOfHoleFits
   | Opt_ShowTypeAppVarsOfHoleFits
   | Opt_ShowDocsOfHoleFits
   | Opt_ShowTypeOfHoleFits
   | Opt_ShowProvOfHoleFits
   | Opt_ShowMatchesOfHoleFits

   | Opt_ShowLoadedModules
   | Opt_HexWordLiterals -- See Note [Print Hexadecimal Literals]

   -- Suppress all coercions, them replacing with '...'
   | Opt_SuppressCoercions
   | Opt_SuppressVarKinds
   -- Suppress module id prefixes on variables.
   | Opt_SuppressModulePrefixes
   -- Suppress type applications.
   | Opt_SuppressTypeApplications
   -- Suppress info such as arity and unfoldings on identifiers.
   | Opt_SuppressIdInfo
   -- Suppress separate type signatures in core, but leave types on
   -- lambda bound vars
   | Opt_SuppressUnfoldings
   -- Suppress the details of even stable unfoldings
   | Opt_SuppressTypeSignatures
   -- Suppress unique ids on variables.
   -- Except for uniques, as some simplifier phases introduce new
   -- variables that have otherwise identical names.
   | Opt_SuppressUniques
   | Opt_SuppressStgExts
   | Opt_SuppressTicks     -- Replaces Opt_PprShowTicks
   | Opt_SuppressTimestamps -- ^ Suppress timestamps in dumps

   -- temporary flags
   | Opt_AutoLinkPackages
   | Opt_ImplicitImportQualified

   -- keeping stuff
   | Opt_KeepHscppFiles
   | Opt_KeepHiDiffs
   | Opt_KeepHcFiles
   | Opt_KeepSFiles
   | Opt_KeepTmpFiles
   | Opt_KeepRawTokenStream
   | Opt_KeepLlvmFiles
   | Opt_KeepHiFiles
   | Opt_KeepOFiles

   | Opt_BuildDynamicToo

   -- safe haskell flags
   | Opt_DistrustAllPackages
   | Opt_PackageTrust
   | Opt_PluginTrustworthy

   | Opt_G_NoStateHack
   | Opt_G_NoOptCoercion
   deriving (Eq, Show, Enum)

-- Check whether a flag should be considered an "optimisation flag"
-- for purposes of recompilation avoidance (see
-- Note [Ignoring some flag changes] in FlagChecker). Being listed here is
-- not a guarantee that the flag has no other effect. We could, and
-- perhaps should, separate out the flags that have some minor impact on
-- program semantics and/or error behavior (e.g., assertions), but
-- then we'd need to go to extra trouble (and an additional flag)
-- to allow users to ignore the optimisation level even though that
-- means ignoring some change.
optimisationFlags :: EnumSet GeneralFlag
optimisationFlags = EnumSet.fromList
   [ Opt_CallArity
   , Opt_Strictness
   , Opt_LateDmdAnal
   , Opt_KillAbsence
   , Opt_KillOneShot
   , Opt_FullLaziness
   , Opt_FloatIn
   , Opt_LateSpecialise
   , Opt_Specialise
   , Opt_SpecialiseAggressively
   , Opt_CrossModuleSpecialise
   , Opt_StaticArgumentTransformation
   , Opt_CSE
   , Opt_StgCSE
   , Opt_StgLiftLams
   , Opt_LiberateCase
   , Opt_SpecConstr
   , Opt_SpecConstrKeen
   , Opt_DoLambdaEtaExpansion
   , Opt_IgnoreAsserts
   , Opt_DoEtaReduction
   , Opt_CaseMerge
   , Opt_CaseFolding
   , Opt_UnboxStrictFields
   , Opt_UnboxSmallStrictFields
   , Opt_DictsCheap
   , Opt_EnableRewriteRules
   , Opt_RegsGraph
   , Opt_RegsIterative
   , Opt_PedanticBottoms
   , Opt_LlvmTBAA
   , Opt_LlvmFillUndefWithGarbage
   , Opt_IrrefutableTuples
   , Opt_CmmSink
   , Opt_CmmElimCommonBlocks
   , Opt_AsmShortcutting
   , Opt_OmitYields
   , Opt_FunToThunk
   , Opt_DictsStrict
   , Opt_DmdTxDictSel
   , Opt_Loopification
   , Opt_CfgBlocklayout
   , Opt_WeightlessBlocklayout
   , Opt_CprAnal
   , Opt_WorkerWrapper
   , Opt_SolveConstantDicts
   , Opt_CatchBottoms
   , Opt_IgnoreAsserts
   ]

-- | Used when outputting warnings: if a reason is given, it is
-- displayed. If a warning isn't controlled by a flag, this is made
-- explicit at the point of use.
data WarnReason
  = NoReason
  -- | Warning was enabled with the flag
  | Reason !WarningFlag
  -- | Warning was made an error because of -Werror or -Werror=WarningFlag
  | ErrReason !(Maybe WarningFlag)
  deriving Show

-- | Used to differentiate the scope an include needs to apply to.
-- We have to split the include paths to avoid accidentally forcing recursive
-- includes since -I overrides the system search paths. See #14312.
data IncludeSpecs
  = IncludeSpecs { includePathsQuote  :: [String]
                 , includePathsGlobal :: [String]
                 }
  deriving Show

-- | Append to the list of includes a path that shall be included using `-I`
-- when the C compiler is called. These paths override system search paths.
addGlobalInclude :: IncludeSpecs -> [String] -> IncludeSpecs
addGlobalInclude spec paths  = let f = includePathsGlobal spec
                               in spec { includePathsGlobal = f ++ paths }

-- | Append to the list of includes a path that shall be included using
-- `-iquote` when the C compiler is called. These paths only apply when quoted
-- includes are used. e.g. #include "foo.h"
addQuoteInclude :: IncludeSpecs -> [String] -> IncludeSpecs
addQuoteInclude spec paths  = let f = includePathsQuote spec
                              in spec { includePathsQuote = f ++ paths }

-- | Concatenate and flatten the list of global and quoted includes returning
-- just a flat list of paths.
flattenIncludes :: IncludeSpecs -> [String]
flattenIncludes specs = includePathsQuote specs ++ includePathsGlobal specs

instance Outputable WarnReason where
  ppr = text . show

instance ToJson WarnReason where
  json NoReason = JSNull
  json (Reason wf) = JSString (show wf)
  json (ErrReason Nothing) = JSString "Opt_WarnIsError"
  json (ErrReason (Just wf)) = JSString (show wf)

data WarningFlag =
-- See Note [Updating flag description in the User's Guide]
     Opt_WarnDuplicateExports
   | Opt_WarnDuplicateConstraints
   | Opt_WarnRedundantConstraints
   | Opt_WarnHiShadows
   | Opt_WarnImplicitPrelude
   | Opt_WarnIncompletePatterns
   | Opt_WarnIncompleteUniPatterns
   | Opt_WarnIncompletePatternsRecUpd
   | Opt_WarnOverflowedLiterals
   | Opt_WarnEmptyEnumerations
   | Opt_WarnMissingFields
   | Opt_WarnMissingImportList
   | Opt_WarnMissingMethods
   | Opt_WarnMissingSignatures
   | Opt_WarnMissingLocalSignatures
   | Opt_WarnNameShadowing
   | Opt_WarnOverlappingPatterns
   | Opt_WarnTypeDefaults
   | Opt_WarnMonomorphism
   | Opt_WarnUnusedTopBinds
   | Opt_WarnUnusedLocalBinds
   | Opt_WarnUnusedPatternBinds
   | Opt_WarnUnusedImports
   | Opt_WarnUnusedMatches
   | Opt_WarnUnusedTypePatterns
   | Opt_WarnUnusedForalls
   | Opt_WarnUnusedRecordWildcards
   | Opt_WarnRedundantRecordWildcards
   | Opt_WarnWarningsDeprecations
   | Opt_WarnDeprecatedFlags
   | Opt_WarnMissingMonadFailInstances -- since 8.0
   | Opt_WarnSemigroup -- since 8.0
   | Opt_WarnDodgyExports
   | Opt_WarnDodgyImports
   | Opt_WarnOrphans
   | Opt_WarnAutoOrphans
   | Opt_WarnIdentities
   | Opt_WarnTabs
   | Opt_WarnUnrecognisedPragmas
   | Opt_WarnDodgyForeignImports
   | Opt_WarnUnusedDoBind
   | Opt_WarnWrongDoBind
   | Opt_WarnAlternativeLayoutRuleTransitional
   | Opt_WarnUnsafe
   | Opt_WarnSafe
   | Opt_WarnTrustworthySafe
   | Opt_WarnMissedSpecs
   | Opt_WarnAllMissedSpecs
   | Opt_WarnUnsupportedCallingConventions
   | Opt_WarnUnsupportedLlvmVersion
   | Opt_WarnMissedExtraSharedLib
   | Opt_WarnInlineRuleShadowing
   | Opt_WarnTypedHoles
   | Opt_WarnPartialTypeSignatures
   | Opt_WarnMissingExportedSignatures
   | Opt_WarnUntickedPromotedConstructors
   | Opt_WarnDerivingTypeable
   | Opt_WarnDeferredTypeErrors
   | Opt_WarnDeferredOutOfScopeVariables
   | Opt_WarnNonCanonicalMonadInstances   -- since 8.0
   | Opt_WarnNonCanonicalMonadFailInstances   -- since 8.0, removed 8.8
   | Opt_WarnNonCanonicalMonoidInstances  -- since 8.0
   | Opt_WarnMissingPatternSynonymSignatures -- since 8.0
   | Opt_WarnUnrecognisedWarningFlags     -- since 8.0
   | Opt_WarnSimplifiableClassConstraints -- Since 8.2
   | Opt_WarnCPPUndef                     -- Since 8.2
   | Opt_WarnUnbangedStrictPatterns       -- Since 8.2
   | Opt_WarnMissingHomeModules           -- Since 8.2
   | Opt_WarnPartialFields                -- Since 8.4
   | Opt_WarnMissingExportList
   | Opt_WarnInaccessibleCode
   | Opt_WarnStarIsType                   -- Since 8.6
   | Opt_WarnStarBinder                   -- Since 8.6
   | Opt_WarnImplicitKindVars             -- Since 8.6
   | Opt_WarnSpaceAfterBang
   | Opt_WarnMissingDerivingStrategies    -- Since 8.8
   | Opt_WarnPrepositiveQualifiedModule   -- Since TBD
   deriving (Eq, Show, Enum)

data Language = Haskell98 | Haskell2010
   deriving (Eq, Enum, Show)

instance Outputable Language where
    ppr = text . show

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

instance Show SafeHaskellMode where
    show Sf_None         = "None"
    show Sf_Unsafe       = "Unsafe"
    show Sf_Trustworthy  = "Trustworthy"
    show Sf_Safe         = "Safe"
    show Sf_Ignore       = "Ignore"

instance Outputable SafeHaskellMode where
    ppr = text . show

-- | Contains not only a collection of 'GeneralFlag'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,
  integerLibrary        :: IntegerLibrary,
    -- ^ IntegerGMP or IntegerSimple. Set at configure time, but may be overriden
    --   by GHC-API users. See Note [The integer library] in PrelNames
  llvmTargets           :: LlvmTargets,
  llvmPasses            :: LlvmPasses,
  verbosity             :: Int,         -- ^ Verbosity level: see Note [Verbosity levels]
  optLevel              :: Int,         -- ^ Optimisation level
  debugLevel            :: Int,         -- ^ How much debug information to produce
  simplPhases           :: Int,         -- ^ Number of simplifier phases
  maxSimplIterations    :: Int,         -- ^ Max simplifier iterations
  maxPmCheckIterations  :: Int,         -- ^ Max no iterations for pm checking
  ruleCheck             :: Maybe String,
  inlineCheck           :: Maybe String, -- ^ A prefix to report inlining decisions about
  strictnessBefore      :: [Int],       -- ^ Additional demand analysis

  parMakeCount          :: Maybe Int,   -- ^ The number of modules to compile in parallel
                                        --   in --make mode, where Nothing ==> compile as
                                        --   many in parallel as there are CPUs.

  enableTimeStats       :: Bool,        -- ^ Enable RTS timing statistics?
  ghcHeapSize           :: Maybe Int,   -- ^ The heap size to set.

  maxRelevantBinds      :: Maybe Int,   -- ^ Maximum number of bindings from the type envt
                                        --   to show in type error messages
  maxValidHoleFits      :: Maybe Int,   -- ^ Maximum number of hole fits to show
                                        --   in typed hole error messages
  maxRefHoleFits        :: Maybe Int,   -- ^ Maximum number of refinement hole
                                        --   fits to show in typed hole error
                                        --   messages
  refLevelHoleFits      :: Maybe Int,   -- ^ Maximum level of refinement for
                                        --   refinement hole fits in typed hole
                                        --   error messages
  maxUncoveredPatterns  :: Int,         -- ^ Maximum number of unmatched patterns to show
                                        --   in non-exhaustiveness warnings
  simplTickFactor       :: Int,         -- ^ Multiplier for simplifier ticks
  specConstrThreshold   :: Maybe Int,   -- ^ Threshold for SpecConstr
  specConstrCount       :: Maybe Int,   -- ^ Max number of specialisations for any one function
  specConstrRecursive   :: Int,         -- ^ Max number of specialisations for recursive types
                                        --   Not optional; otherwise ForceSpecConstr can diverge.
  binBlobThreshold      :: Word,        -- ^ Binary literals (e.g. strings) whose size is above
                                        --   this threshold will be dumped in a binary file
                                        --   by the assembler code generator (0 to disable)
  liberateCaseThreshold :: Maybe Int,   -- ^ Threshold for LiberateCase
  floatLamArgs          :: Maybe Int,   -- ^ Arg count for lambda floating
                                        --   See CoreMonad.FloatOutSwitches

  liftLamsRecArgs       :: Maybe Int,   -- ^ Maximum number of arguments after lambda lifting a
                                        --   recursive function.
  liftLamsNonRecArgs    :: Maybe Int,   -- ^ Maximum number of arguments after lambda lifting a
                                        --   non-recursive function.
  liftLamsKnown         :: Bool,        -- ^ Lambda lift even when this turns a known call
                                        --   into an unknown call.

  cmmProcAlignment      :: Maybe Int,   -- ^ Align Cmm functions at this boundary or use default.

  historySize           :: Int,         -- ^ Simplification history size

  importPaths           :: [FilePath],
  mainModIs             :: Module,
  mainFunIs             :: Maybe String,
  reductionDepth        :: IntWithInf,   -- ^ Typechecker maximum stack depth
  solverIterations      :: IntWithInf,   -- ^ Number of iterations in the constraints solver
                                         --   Typically only 1 is needed

  thisInstalledUnitId   :: InstalledUnitId,
  thisComponentId_      :: Maybe ComponentId,
  thisUnitIdInsts_      :: Maybe [(ModuleName, Module)],

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

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

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

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

  canGenerateDynamicToo :: IORef Bool,
  dynObjectSuf          :: String,
  dynHiSuf              :: String,

  outputFile            :: Maybe String,
  dynOutputFile         :: 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,

  ldInputs              :: [Option],

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

  rtsOpts               :: Maybe String,
  rtsOptsEnabled        :: RtsOptsEnabled,
  rtsOptsSuggestions    :: Bool,

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

  -- Plugins
  pluginModNames        :: [ModuleName],
  pluginModNameOpts     :: [(ModuleName,String)],
  frontendPluginOpts    :: [String],
    -- ^ the @-ffrontend-opt@ flags given on the command line, in *reverse*
    -- order that they're specified on the command line.
  cachedPlugins         :: [LoadedPlugin],
    -- ^ plugins dynamically loaded after processing arguments. What will be
    -- loaded here is directed by pluginModNames. Arguments are loaded from
    -- 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
    -- 'DynamicLoading.initializePlugins'.
  staticPlugins            :: [StaticPlugin],
    -- ^ staic 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.

  -- GHC API hooks
  hooks                 :: Hooks,

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

  --  Package flags
  packageDBFlags        :: [PackageDBFlag],
        -- ^ The @-package-db@ flags given on the command line, In
        -- *reverse* order that they're specified on the command line.
        -- This is intended to be applied with the list of "initial"
        -- package databases derived from @GHC_PACKAGE_PATH@; see
        -- 'getPackageConfRefs'.

  ignorePackageFlags    :: [IgnorePackageFlag],
        -- ^ The @-ignore-package@ flags from the command line.
        -- In *reverse* order that they're specified on the command line.
  packageFlags          :: [PackageFlag],
        -- ^ The @-package@ and @-hide-package@ flags from the command-line.
        -- In *reverse* order that they're specified on the command line.
  pluginPackageFlags    :: [PackageFlag],
        -- ^ The @-plugin-package-id@ flags from command line.
        -- In *reverse* order that they're specified on the command line.
  trustFlags            :: [TrustFlag],
        -- ^ The @-trust@ and @-distrust@ flags.
        -- In *reverse* order that they're specified on the command line.
  packageEnv            :: Maybe FilePath,
        -- ^ Filepath to the package environment file (if overriding default)

  -- Package state
  -- NB. do not modify this field, it is calculated by
  -- Packages.initPackages
  pkgDatabase           :: Maybe [(FilePath, [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 FilesToClean,
  dirsToClean           :: IORef (Map FilePath FilePath),
  -- The next available suffix to uniquely name a temp file, updated atomically
  nextTempSuffix        :: IORef Int,

  -- 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
  dumpFlags             :: EnumSet DumpFlag,
  generalFlags          :: EnumSet GeneralFlag,
  warningFlags          :: EnumSet WarningFlag,
  fatalWarningFlags     :: EnumSet WarningFlag,
  -- Don't change this without updating extensionFlags:
  language              :: Maybe Language,
  -- | Safe Haskell mode
  safeHaskell           :: SafeHaskellMode,
  safeInfer             :: Bool,
  safeInferred          :: Bool,
  -- 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,
  overlapInstLoc        :: SrcSpan,
  incoherentOnLoc       :: SrcSpan,
  pkgTrustOnLoc         :: SrcSpan,
  warnSafeOnLoc         :: SrcSpan,
  warnUnsafeOnLoc       :: SrcSpan,
  trustworthyOnLoc      :: SrcSpan,
  -- Don't change this without updating extensionFlags:
  -- Here we collect the settings of the language extensions
  -- from the command line, the ghci config file and
  -- from interactive :set / :seti commands.
  extensions            :: [OnOff LangExt.Extension],
  -- extensionFlags should always be equal to
  --     flattenExtensionFlags language extensions
  -- LangExt.Extension is defined in libraries/ghc-boot so that it can be used
  -- by template-haskell
  extensionFlags        :: EnumSet LangExt.Extension,

  -- Unfolding control
  -- See Note [Discounts and thresholds] in CoreUnfold
  ufCreationThreshold   :: Int,
  ufUseThreshold        :: Int,
  ufFunAppDiscount      :: Int,
  ufDictDiscount        :: Int,
  ufKeenessFactor       :: Float,
  ufDearOp              :: Int,
  ufVeryAggressive      :: Bool,

  maxWorkerArgs         :: Int,

  ghciHistSize          :: Int,

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

  ghcVersionFile        :: Maybe FilePath,
  haddockOptions        :: Maybe String,

  -- | GHCi scripts specified by -ghci-script, in reverse order
  ghciScripts           :: [String],

  -- Output style options
  pprUserLength         :: Int,
  pprCols               :: Int,

  useUnicode            :: Bool,
  useColor              :: OverridingBool,
  canUseColor           :: Bool,
  colScheme             :: Col.Scheme,

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

  interactivePrint      :: Maybe String,

  nextWrapperNum        :: IORef (ModuleEnv Int),

  -- | Machine dependent flags (-m<blah> stuff)
  sseVersion            :: Maybe SseVersion,
  bmiVersion            :: Maybe BmiVersion,
  avx                   :: Bool,
  avx2                  :: Bool,
  avx512cd              :: Bool, -- Enable AVX-512 Conflict Detection Instructions.
  avx512er              :: Bool, -- Enable AVX-512 Exponential and Reciprocal Instructions.
  avx512f               :: Bool, -- Enable AVX-512 instructions.
  avx512pf              :: Bool, -- Enable AVX-512 PreFetch Instructions.

  -- | Run-time linker information (what options we need, etc.)
  rtldInfo              :: IORef (Maybe LinkerInfo),

  -- | Run-time compiler information
  rtccInfo              :: IORef (Maybe CompilerInfo),

  -- Constants used to control the amount of optimization done.

  -- | Max size, in bytes, of inline array allocations.
  maxInlineAllocSize    :: Int,

  -- | Only inline memcpy if it generates no more than this many
  -- pseudo (roughly: Cmm) instructions.
  maxInlineMemcpyInsns  :: Int,

  -- | Only inline memset if it generates no more than this many
  -- pseudo (roughly: Cmm) instructions.
  maxInlineMemsetInsns  :: Int,

  -- | Reverse the order of error messages in GHC/GHCi
  reverseErrors         :: Bool,

  -- | Limit the maximum number of errors to show
  maxErrors             :: Maybe Int,

  -- | Unique supply configuration for testing build determinism
  initialUnique         :: Int,
  uniqueIncrement       :: Int,

  -- | Temporary: CFG Edge weights for fast iterations
  cfgWeightInfo         :: CfgWeights
}

-- | Edge weights to use when generating a CFG from CMM
data CfgWeights
    = CFGWeights
    { uncondWeight :: Int
    , condBranchWeight :: Int
    , switchWeight :: Int
    , callWeight :: Int
    , likelyCondWeight :: Int
    , unlikelyCondWeight :: Int
    , infoTablePenalty :: Int
    , backEdgeBonus :: Int
    }

defaultCfgWeights :: CfgWeights
defaultCfgWeights
    = CFGWeights
    { uncondWeight = 1000
    , condBranchWeight = 800
    , switchWeight = 1
    , callWeight = -10
    , likelyCondWeight = 900
    , unlikelyCondWeight = 300
    , infoTablePenalty = 300
    , backEdgeBonus = 400
    }

parseCfgWeights :: String -> CfgWeights -> CfgWeights
parseCfgWeights s oldWeights =
        foldl' (\cfg (n,v) -> update n v cfg) oldWeights assignments
    where
        assignments = map assignment $ settings s
        update "uncondWeight" n w =
            w {uncondWeight = n}
        update "condBranchWeight" n w =
            w {condBranchWeight = n}
        update "switchWeight" n w =
            w {switchWeight = n}
        update "callWeight" n w =
            w {callWeight = n}
        update "likelyCondWeight" n w =
            w {likelyCondWeight = n}
        update "unlikelyCondWeight" n w =
            w {unlikelyCondWeight = n}
        update "infoTablePenalty" n w =
            w {infoTablePenalty = n}
        update "backEdgeBonus" n w =
            w {backEdgeBonus = n}
        update other _ _
            = panic $ other ++
                      " is not a cfg weight parameter. " ++
                      exampleString
        settings s
            | (s1,rest) <- break (== ',') s
            , null rest
            = [s1]
            | (s1,rest) <- break (== ',') s
            = [s1] ++ settings (drop 1 rest)
            | otherwise = panic $ "Invalid cfg parameters." ++ exampleString
        assignment as
            | (name, _:val) <- break (== '=') as
            = (name,read val)
            | otherwise
            = panic $ "Invalid cfg parameters." ++ exampleString
        exampleString = "Example parameters: uncondWeight=1000," ++
            "condBranchWeight=800,switchWeight=0,callWeight=300" ++
            ",likelyCondWeight=900,unlikelyCondWeight=300" ++
            ",infoTablePenalty=300,backEdgeBonus=400"

backendMaintainsCfg :: DynFlags -> Bool
backendMaintainsCfg dflags = case (platformArch $ targetPlatform dflags) of
    -- ArchX86 -- Should work but not tested so disabled currently.
    ArchX86_64 -> True
    _otherwise -> False

class HasDynFlags m where
    getDynFlags :: m DynFlags

{- It would be desirable to have the more generalised

  instance (MonadTrans t, Monad m, HasDynFlags m) => HasDynFlags (t m) where
      getDynFlags = lift getDynFlags

instance definition. However, that definition would overlap with the
`HasDynFlags (GhcT m)` instance. Instead we define instances for a
couple of common Monad transformers explicitly. -}

instance (Monoid a, Monad m, HasDynFlags m) => HasDynFlags (WriterT a m) where
    getDynFlags = lift getDynFlags

instance (Monad m, HasDynFlags m) => HasDynFlags (ReaderT a m) where
    getDynFlags = lift getDynFlags

instance (Monad m, HasDynFlags m) => HasDynFlags (MaybeT m) where
    getDynFlags = lift getDynFlags

instance (Monad m, HasDynFlags m) => HasDynFlags (ExceptT e m) where
    getDynFlags = lift getDynFlags

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 (Eq,Enum)

data LlvmTarget = LlvmTarget
  { lDataLayout :: String
  , lCPU        :: String
  , lAttributes :: [String]
  }

type LlvmTargets = [(String, LlvmTarget)]
type LlvmPasses = [(Int, String)]
type LlvmConfig = (LlvmTargets, LlvmPasses)

data IntegerLibrary
    = IntegerGMP
    | IntegerSimple
    deriving (Read, Show, Eq)

data Settings = Settings {
  sTargetPlatform        :: Platform,       -- Filled in by SysTools
  sGhcUsagePath          :: FilePath,       -- ditto
  sGhciUsagePath         :: FilePath,       -- ditto
  sToolDir               :: Maybe FilePath, -- ditto
  sTopDir                :: FilePath,       -- ditto
  sTmpDir                :: String,      -- no trailing '/'
  sProgramName           :: String,
  sProjectVersion        :: String,
  -- 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,
  sLdSupportsCompactUnwind :: Bool,
  sLdSupportsBuildId       :: Bool,
  sLdSupportsFilelist      :: Bool,
  sLdIsGnuLd               :: Bool,
  sGccSupportsNoPie        :: Bool,
  -- commands for particular phases
  sPgm_L                 :: String,
  sPgm_P                 :: (String,[Option]),
  sPgm_F                 :: String,
  sPgm_c                 :: (String,[Option]),
  sPgm_a                 :: (String,[Option]),
  sPgm_l                 :: (String,[Option]),
  sPgm_dll               :: (String,[Option]),
  sPgm_T                 :: String,
  sPgm_windres           :: String,
  sPgm_libtool           :: String,
  sPgm_ar                :: String,
  sPgm_ranlib            :: String,
  sPgm_lo                :: (String,[Option]), -- LLVM: opt llvm optimiser
  sPgm_lc                :: (String,[Option]), -- LLVM: llc static compiler
  sPgm_lcc               :: (String,[Option]), -- LLVM: c compiler
  sPgm_i                 :: String,
  -- options for particular phases
  sOpt_L                 :: [String],
  sOpt_P                 :: [String],
  sOpt_P_fingerprint     :: Fingerprint, -- cached Fingerprint of sOpt_P
                                         -- See Note [Repeated -optP hashing]
  sOpt_F                 :: [String],
  sOpt_c                 :: [String],
  sOpt_cxx               :: [String],
  sOpt_a                 :: [String],
  sOpt_l                 :: [String],
  sOpt_windres           :: [String],
  sOpt_lo                :: [String], -- LLVM: llvm optimiser
  sOpt_lc                :: [String], -- LLVM: llc static compiler
  sOpt_lcc               :: [String], -- LLVM: c compiler
  sOpt_i                 :: [String], -- iserv options

  sPlatformConstants     :: PlatformConstants,

  -- Formerly Config.hs, target specific
  sTargetPlatformString :: String, -- TODO Recalculate string from richer info?
  sIntegerLibrary        :: String,
  sIntegerLibraryType    :: IntegerLibrary,
  sGhcWithInterpreter    :: Bool,
  sGhcWithNativeCodeGen  :: Bool,
  sGhcWithSMP            :: Bool,
  sGhcRTSWays            :: String,
  sTablesNextToCode      :: Bool,
  sLeadingUnderscore     :: Bool,
  sLibFFI                :: Bool,
  sGhcThreaded           :: Bool,
  sGhcDebugged           :: Bool,
  sGhcRtsWithLibdw       :: Bool
 }

targetPlatform :: DynFlags -> Platform
targetPlatform dflags = sTargetPlatform (settings dflags)
programName :: DynFlags -> String
programName dflags = sProgramName (settings dflags)
projectVersion :: DynFlags -> String
projectVersion dflags = sProjectVersion (settings dflags)
ghcUsagePath          :: DynFlags -> FilePath
ghcUsagePath dflags = sGhcUsagePath (settings dflags)
ghciUsagePath         :: DynFlags -> FilePath
ghciUsagePath dflags = sGhciUsagePath (settings dflags)
toolDir               :: DynFlags -> Maybe FilePath
toolDir dflags = sToolDir (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_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_windres           :: DynFlags -> String
pgm_windres dflags = sPgm_windres (settings dflags)
pgm_libtool           :: DynFlags -> String
pgm_libtool dflags = sPgm_libtool (settings dflags)
pgm_lcc               :: DynFlags -> (String,[Option])
pgm_lcc dflags = sPgm_lcc (settings dflags)
pgm_ar                :: DynFlags -> String
pgm_ar dflags = sPgm_ar (settings dflags)
pgm_ranlib            :: DynFlags -> String
pgm_ranlib dflags = sPgm_ranlib (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)
pgm_i                 :: DynFlags -> String
pgm_i dflags = sPgm_i (settings dflags)
opt_L                 :: DynFlags -> [String]
opt_L dflags = sOpt_L (settings dflags)
opt_P                 :: DynFlags -> [String]
opt_P dflags = concatMap (wayOptP (targetPlatform dflags)) (ways dflags)
            ++ sOpt_P (settings dflags)

-- This function packages everything that's needed to fingerprint opt_P
-- flags. See Note [Repeated -optP hashing].
opt_P_signature       :: DynFlags -> ([String], Fingerprint)
opt_P_signature dflags =
  ( concatMap (wayOptP (targetPlatform dflags)) (ways dflags)
  , sOpt_P_fingerprint (settings dflags))

opt_F                 :: DynFlags -> [String]
opt_F dflags = sOpt_F (settings dflags)
opt_c                 :: DynFlags -> [String]
opt_c dflags = concatMap (wayOptc (targetPlatform dflags)) (ways dflags)
            ++ sOpt_c (settings dflags)
opt_cxx               :: DynFlags -> [String]
opt_cxx dflags = sOpt_cxx (settings dflags)
opt_a                 :: DynFlags -> [String]
opt_a dflags = sOpt_a (settings dflags)
opt_l                 :: DynFlags -> [String]
opt_l dflags = concatMap (wayOptl (targetPlatform dflags)) (ways dflags)
            ++ sOpt_l (settings dflags)
opt_windres           :: DynFlags -> [String]
opt_windres dflags = sOpt_windres (settings dflags)
opt_lcc                :: DynFlags -> [String]
opt_lcc dflags = sOpt_lcc (settings dflags)
opt_lo                :: DynFlags -> [String]
opt_lo dflags = sOpt_lo (settings dflags)
opt_lc                :: DynFlags -> [String]
opt_lc dflags = sOpt_lc (settings dflags)
opt_i                 :: DynFlags -> [String]
opt_i dflags = sOpt_i (settings dflags)

-- | The directory for this version of ghc in the user's app directory
-- (typically something like @~/.ghc/x86_64-linux-7.6.3@)
--
versionedAppDir :: DynFlags -> MaybeT IO FilePath
versionedAppDir dflags = do
  -- Make sure we handle the case the HOME isn't set (see #11678)
  appdir <- tryMaybeT $ getAppUserDataDirectory (programName dflags)
  return $ appdir </> versionedFilePath dflags

-- | A filepath like @x86_64-linux-7.6.3@ with the platform string to use when
-- constructing platform-version-dependent files that need to co-exist.
--
versionedFilePath :: DynFlags -> FilePath
versionedFilePath dflags =     TARGET_ARCH
                        ++ '-':TARGET_OS
                        ++ '-':projectVersion dflags
  -- NB: This functionality is reimplemented in Cabal, so if you
  -- change it, be sure to update Cabal.

-- | 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:
--
--  * If a program uses Template Haskell the typechecker may need to run code
--    from an imported module.  To facilitate this, code generation is enabled
--    for modules imported by modules that use template haskell.
--    See Note [-fno-code mode].
--
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)

-- | 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 = text "CompManager"
  ppr OneShot     = text "OneShot"
  ppr MkDepend    = text "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)
  | LinkStaticLib       -- ^ Link objects into a static lib
  deriving (Eq, Show)

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

-- | We accept flags which make packages visible, but how they select
-- the package varies; this data type reflects what selection criterion
-- is used.
data PackageArg =
      PackageArg String    -- ^ @-package@, by 'PackageName'
    | UnitIdArg UnitId     -- ^ @-package-id@, by 'UnitId'
  deriving (Eq, Show)
instance Outputable PackageArg where
    ppr (PackageArg pn) = text "package" <+> text pn
    ppr (UnitIdArg uid) = text "unit" <+> ppr uid

-- | Represents the renaming that may be associated with an exposed
-- package, e.g. the @rns@ part of @-package "foo (rns)"@.
--
-- Here are some example parsings of the package flags (where
-- a string literal is punned to be a 'ModuleName':
--
--      * @-package foo@ is @ModRenaming True []@
--      * @-package foo ()@ is @ModRenaming False []@
--      * @-package foo (A)@ is @ModRenaming False [("A", "A")]@
--      * @-package foo (A as B)@ is @ModRenaming False [("A", "B")]@
--      * @-package foo with (A as B)@ is @ModRenaming True [("A", "B")]@
data ModRenaming = ModRenaming {
    modRenamingWithImplicit :: Bool, -- ^ Bring all exposed modules into scope?
    modRenamings :: [(ModuleName, ModuleName)] -- ^ Bring module @m@ into scope
                                               --   under name @n@.
  } deriving (Eq)
instance Outputable ModRenaming where
    ppr (ModRenaming b rns) = ppr b <+> parens (ppr rns)

-- | Flags for manipulating the set of non-broken packages.
newtype IgnorePackageFlag = IgnorePackage String -- ^ @-ignore-package@
  deriving (Eq)

-- | Flags for manipulating package trust.
data TrustFlag
  = TrustPackage    String -- ^ @-trust@
  | DistrustPackage String -- ^ @-distrust@
  deriving (Eq)

-- | Flags for manipulating packages visibility.
data PackageFlag
  = ExposePackage   String PackageArg ModRenaming -- ^ @-package@, @-package-id@
  | HidePackage     String -- ^ @-hide-package@
  deriving (Eq) -- NB: equality instance is used by packageFlagsChanged

data PackageDBFlag
  = PackageDB PkgConfRef
  | NoUserPackageDB
  | NoGlobalPackageDB
  | ClearPackageDBs
  deriving (Eq)

packageFlagsChanged :: DynFlags -> DynFlags -> Bool
packageFlagsChanged idflags1 idflags0 =
  packageFlags idflags1 /= packageFlags idflags0 ||
  ignorePackageFlags idflags1 /= ignorePackageFlags idflags0 ||
  pluginPackageFlags idflags1 /= pluginPackageFlags idflags0 ||
  trustFlags idflags1 /= trustFlags idflags0 ||
  packageDBFlags idflags1 /= packageDBFlags idflags0 ||
  packageGFlags idflags1 /= packageGFlags idflags0
 where
   packageGFlags dflags = map (`gopt` dflags)
     [ Opt_HideAllPackages
     , Opt_HideAllPluginPackages
     , Opt_AutoLinkPackages ]

instance Outputable PackageFlag where
    ppr (ExposePackage n arg rn) = text n <> braces (ppr arg <+> ppr rn)
    ppr (HidePackage str) = text "-hide-package" <+> text str

defaultHscTarget :: Settings -> HscTarget
defaultHscTarget = defaultObjectTarget

-- | The 'HscTarget' value corresponding to the default way to create
-- object files on the current platform.
defaultObjectTarget :: Settings -> HscTarget
defaultObjectTarget settings
  | platformUnregisterised platform     =  HscC
  | sGhcWithNativeCodeGen settings      =  HscAsm
  | otherwise                           =  HscLlvm
  where
    platform = sTargetPlatform settings

-- Determines whether we will be compiling
-- info tables that reside just before the entry code, or with an
-- indirection to the entry code.  See TABLES_NEXT_TO_CODE in
-- includes/rts/storage/InfoTables.h.
tablesNextToCode :: DynFlags -> Bool
tablesNextToCode dflags =
    not (platformUnregisterised $ targetPlatform dflags) &&
    sTablesNextToCode (settings dflags)

data DynLibLoader
  = Deployable
  | SystemDependent
  deriving Eq

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

shouldUseColor :: DynFlags -> Bool
shouldUseColor dflags = overrideWith (canUseColor dflags) (useColor dflags)

shouldUseHexWordLiterals :: DynFlags -> Bool
shouldUseHexWordLiterals dflags =
  Opt_HexWordLiterals `EnumSet.member` generalFlags dflags

-- | Are we building with @-fPIE@ or @-fPIC@ enabled?
positionIndependent :: DynFlags -> Bool
positionIndependent dflags = gopt Opt_PIC dflags || gopt Opt_PIE dflags

-----------------------------------------------------------------------------
-- Ways

-- The central concept of a "way" is that all objects in a given
-- program must be compiled in the same "way".  Certain options change
-- parameters of the virtual machine, eg. profiling adds an extra word
-- to the object header, so profiling objects cannot be linked with
-- non-profiling objects.

-- After parsing the command-line options, we determine which "way" we
-- are building - this might be a combination way, eg. profiling+threaded.

-- We then find the "build-tag" associated with this way, and this
-- becomes the suffix used to find .hi files and libraries used in
-- this compilation.

data Way
  = WayCustom String -- for GHC API clients building custom variants
  | WayThreaded
  | WayDebug
  | WayProf
  | WayEventLog
  | WayDyn
  deriving (Eq, Ord, Show)

allowed_combination :: [Way] -> Bool
allowed_combination way = and [ x `allowedWith` y
                              | x <- way, y <- way, x < y ]
  where
        -- Note ordering in these tests: the left argument is
        -- <= the right argument, according to the Ord instance
        -- on Way above.

        -- dyn is allowed with everything
        _ `allowedWith` WayDyn                  = True
        WayDyn `allowedWith` _                  = True

        -- debug is allowed with everything
        _ `allowedWith` WayDebug                = True
        WayDebug `allowedWith` _                = True

        (WayCustom {}) `allowedWith` _          = True
        WayThreaded `allowedWith` WayProf       = True
        WayThreaded `allowedWith` WayEventLog   = True
        WayProf     `allowedWith` WayEventLog   = True
        _ `allowedWith` _                       = False

mkBuildTag :: [Way] -> String
mkBuildTag ways = concat (intersperse "_" (map wayTag ways))

wayTag :: Way -> String
wayTag (WayCustom xs) = xs
wayTag WayThreaded = "thr"
wayTag WayDebug    = "debug"
wayTag WayDyn      = "dyn"
wayTag WayProf     = "p"
wayTag WayEventLog = "l"

wayRTSOnly :: Way -> Bool
wayRTSOnly (WayCustom {}) = False
wayRTSOnly WayThreaded = True
wayRTSOnly WayDebug    = True
wayRTSOnly WayDyn      = False
wayRTSOnly WayProf     = False
wayRTSOnly WayEventLog = True

wayDesc :: Way -> String
wayDesc (WayCustom xs) = xs
wayDesc WayThreaded = "Threaded"
wayDesc WayDebug    = "Debug"
wayDesc WayDyn      = "Dynamic"
wayDesc WayProf     = "Profiling"
wayDesc WayEventLog = "RTS Event Logging"

-- Turn these flags on when enabling this way
wayGeneralFlags :: Platform -> Way -> [GeneralFlag]
wayGeneralFlags _ (WayCustom {}) = []
wayGeneralFlags _ WayThreaded = []
wayGeneralFlags _ WayDebug    = []
wayGeneralFlags _ WayDyn      = [Opt_PIC, Opt_ExternalDynamicRefs]
    -- We could get away without adding -fPIC when compiling the
    -- modules of a program that is to be linked with -dynamic; the
    -- program itself does not need to be position-independent, only
    -- the libraries need to be.  HOWEVER, GHCi links objects into a
    -- .so before loading the .so using the system linker.  Since only
    -- PIC objects can be linked into a .so, we have to compile even
    -- modules of the main program with -fPIC when using -dynamic.
wayGeneralFlags _ WayProf     = [Opt_SccProfilingOn]
wayGeneralFlags _ WayEventLog = []

-- Turn these flags off when enabling this way
wayUnsetGeneralFlags :: Platform -> Way -> [GeneralFlag]
wayUnsetGeneralFlags _ (WayCustom {}) = []
wayUnsetGeneralFlags _ WayThreaded = []
wayUnsetGeneralFlags _ WayDebug    = []
wayUnsetGeneralFlags _ WayDyn      = [-- There's no point splitting
                                      -- when we're going to be dynamically
                                      -- linking. Plus it breaks compilation
                                      -- on OSX x86.
                                      Opt_SplitSections]
wayUnsetGeneralFlags _ WayProf     = []
wayUnsetGeneralFlags _ WayEventLog = []

wayOptc :: Platform -> Way -> [String]
wayOptc _ (WayCustom {}) = []
wayOptc platform WayThreaded = case platformOS platform of
                               OSOpenBSD -> ["-pthread"]
                               OSNetBSD  -> ["-pthread"]
                               _         -> []
wayOptc _ WayDebug      = []
wayOptc _ WayDyn        = []
wayOptc _ WayProf       = ["-DPROFILING"]
wayOptc _ WayEventLog   = ["-DTRACING"]

wayOptl :: Platform -> Way -> [String]
wayOptl _ (WayCustom {}) = []
wayOptl platform WayThreaded =
        case platformOS platform of
        OSFreeBSD  -> ["-pthread"]
        OSOpenBSD  -> ["-pthread"]
        OSNetBSD   -> ["-pthread"]
        _          -> []
wayOptl _ WayDebug      = []
wayOptl _ WayDyn        = []
wayOptl _ WayProf       = []
wayOptl _ WayEventLog   = []

wayOptP :: Platform -> Way -> [String]
wayOptP _ (WayCustom {}) = []
wayOptP _ WayThreaded = []
wayOptP _ WayDebug    = []
wayOptP _ WayDyn      = []
wayOptP _ WayProf     = ["-DPROFILING"]
wayOptP _ WayEventLog = ["-DTRACING"]

whenGeneratingDynamicToo :: MonadIO m => DynFlags -> m () -> m ()
whenGeneratingDynamicToo dflags f = ifGeneratingDynamicToo dflags f (return ())

ifGeneratingDynamicToo :: MonadIO m => DynFlags -> m a -> m a -> m a
ifGeneratingDynamicToo dflags f g = generateDynamicTooConditional dflags f g g

whenCannotGenerateDynamicToo :: MonadIO m => DynFlags -> m () -> m ()
whenCannotGenerateDynamicToo dflags f
    = ifCannotGenerateDynamicToo dflags f (return ())

ifCannotGenerateDynamicToo :: MonadIO m => DynFlags -> m a -> m a -> m a
ifCannotGenerateDynamicToo dflags f g
    = generateDynamicTooConditional dflags g f g

generateDynamicTooConditional :: MonadIO m
                              => DynFlags -> m a -> m a -> m a -> m a
generateDynamicTooConditional dflags canGen cannotGen notTryingToGen
    = if gopt Opt_BuildDynamicToo dflags
      then do let ref = canGenerateDynamicToo dflags
              b <- liftIO $ readIORef ref
              if b then canGen else cannotGen
      else notTryingToGen

dynamicTooMkDynamicDynFlags :: DynFlags -> DynFlags
dynamicTooMkDynamicDynFlags dflags0
    = let dflags1 = addWay' WayDyn dflags0
          dflags2 = dflags1 {
                        outputFile = dynOutputFile dflags1,
                        hiSuf = dynHiSuf dflags1,
                        objectSuf = dynObjectSuf dflags1
                    }
          dflags3 = updateWays dflags2
          dflags4 = gopt_unset dflags3 Opt_BuildDynamicToo
      in dflags4

-- | Compute the path of the dynamic object corresponding to an object file.
dynamicOutputFile :: DynFlags -> FilePath -> FilePath
dynamicOutputFile dflags outputFile = dynOut outputFile
  where
    dynOut = flip addExtension (dynObjectSuf dflags) . dropExtension

-----------------------------------------------------------------------------

-- | Used by 'GHC.runGhc' to partially initialize a new 'DynFlags' value
initDynFlags :: DynFlags -> IO DynFlags
initDynFlags dflags = do
 let -- We can't build with dynamic-too on Windows, as labels before
     -- the fork point are different depending on whether we are
     -- building dynamically or not.
     platformCanGenerateDynamicToo
         = platformOS (targetPlatform dflags) /= OSMinGW32
 refCanGenerateDynamicToo <- newIORef platformCanGenerateDynamicToo
 refNextTempSuffix <- newIORef 0
 refFilesToClean <- newIORef emptyFilesToClean
 refDirsToClean <- newIORef Map.empty
 refGeneratedDumps <- newIORef Set.empty
 refRtldInfo <- newIORef Nothing
 refRtccInfo <- newIORef Nothing
 wrapperNum <- newIORef emptyModuleEnv
 canUseUnicode <- do let enc = localeEncoding
                         str = "‘’"
                     (withCString enc str $ \cstr ->
                          do str' <- peekCString enc cstr
                             return (str == str'))
                         `catchIOError` \_ -> return False
 canUseColor <- stderrSupportsAnsiColors
 maybeGhcColorsEnv  <- lookupEnv "GHC_COLORS"
 maybeGhcColoursEnv <- lookupEnv "GHC_COLOURS"
 let adjustCols (Just env) = Col.parseScheme env
     adjustCols Nothing    = id
 let (useColor', colScheme') =
       (adjustCols maybeGhcColoursEnv . adjustCols maybeGhcColorsEnv)
       (useColor dflags, colScheme dflags)
 return dflags{
        canGenerateDynamicToo = refCanGenerateDynamicToo,
        nextTempSuffix = refNextTempSuffix,
        filesToClean   = refFilesToClean,
        dirsToClean    = refDirsToClean,
        generatedDumps = refGeneratedDumps,
        nextWrapperNum = wrapperNum,
        useUnicode    = canUseUnicode,
        useColor      = useColor',
        canUseColor   = canUseColor,
        colScheme     = colScheme',
        rtldInfo      = refRtldInfo,
        rtccInfo      = refRtccInfo
        }

-- | The normal 'DynFlags'. Note that they are not suitable for use in this form
-- and must be fully initialized by 'GHC.runGhc' first.
defaultDynFlags :: Settings -> LlvmConfig -> DynFlags
defaultDynFlags mySettings (myLlvmTargets, myLlvmPasses) =
-- See Note [Updating flag description in the User's Guide]
     DynFlags {
        ghcMode                 = CompManager,
        ghcLink                 = LinkBinary,
        hscTarget               = defaultHscTarget mySettings,
        integerLibrary          = sIntegerLibraryType mySettings,
        verbosity               = 0,
        optLevel                = 0,
        debugLevel              = 0,
        simplPhases             = 2,
        maxSimplIterations      = 4,
        maxPmCheckIterations    = 2000000,
        ruleCheck               = Nothing,
        inlineCheck             = Nothing,
        binBlobThreshold        = 500000, -- 500K is a good default (see #16190)
        maxRelevantBinds        = Just 6,
        maxValidHoleFits   = Just 6,
        maxRefHoleFits     = Just 6,
        refLevelHoleFits   = Nothing,
        maxUncoveredPatterns    = 4,
        simplTickFactor         = 100,
        specConstrThreshold     = Just 2000,
        specConstrCount         = Just 3,
        specConstrRecursive     = 3,
        liberateCaseThreshold   = Just 2000,
        floatLamArgs            = Just 0, -- Default: float only if no fvs
        liftLamsRecArgs         = Just 5, -- Default: the number of available argument hardware registers on x86_64
        liftLamsNonRecArgs      = Just 5, -- Default: the number of available argument hardware registers on x86_64
        liftLamsKnown           = False,  -- Default: don't turn known calls into unknown ones
        cmmProcAlignment        = Nothing,

        historySize             = 20,
        strictnessBefore        = [],

        parMakeCount            = Just 1,

        enableTimeStats         = False,
        ghcHeapSize             = Nothing,

        importPaths             = ["."],
        mainModIs               = mAIN,
        mainFunIs               = Nothing,
        reductionDepth          = treatZeroAsInf mAX_REDUCTION_DEPTH,
        solverIterations        = treatZeroAsInf mAX_SOLVER_ITERATIONS,

        thisInstalledUnitId     = toInstalledUnitId mainUnitId,
        thisUnitIdInsts_        = Nothing,
        thisComponentId_        = Nothing,

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

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

        canGenerateDynamicToo   = panic "defaultDynFlags: No canGenerateDynamicToo",
        dynObjectSuf            = "dyn_" ++ phaseInputExt StopLn,
        dynHiSuf                = "dyn_hi",

        pluginModNames          = [],
        pluginModNameOpts       = [],
        frontendPluginOpts      = [],
        cachedPlugins           = [],
        staticPlugins           = [],
        hooks                   = emptyHooks,

        outputFile              = Nothing,
        dynOutputFile           = Nothing,
        outputHi                = Nothing,
        dynLibLoader            = SystemDependent,
        dumpPrefix              = Nothing,
        dumpPrefixForce         = Nothing,
        ldInputs                = [],
        includePaths            = IncludeSpecs [] [],
        libraryPaths            = [],
        frameworkPaths          = [],
        cmdlineFrameworks       = [],
        rtsOpts                 = Nothing,
        rtsOptsEnabled          = RtsOptsSafeOnly,
        rtsOptsSuggestions      = True,

        hpcDir                  = ".hpc",

        packageDBFlags          = [],
        packageFlags            = [],
        pluginPackageFlags      = [],
        ignorePackageFlags      = [],
        trustFlags              = [],
        packageEnv              = Nothing,
        pkgDatabase             = Nothing,
        -- This gets filled in with GHC.setSessionDynFlags
        pkgState                = emptyPackageState,
        ways                    = defaultWays mySettings,
        buildTag                = mkBuildTag (defaultWays mySettings),
        splitInfo               = Nothing,
        settings                = mySettings,
        llvmTargets             = myLlvmTargets,
        llvmPasses              = myLlvmPasses,

        -- ghc -M values
        depMakefile       = "Makefile",
        depIncludePkgDeps = False,
        depIncludeCppDeps = False,
        depExcludeMods    = [],
        depSuffixes       = [],
        -- end of ghc -M values
        nextTempSuffix = panic "defaultDynFlags: No nextTempSuffix",
        filesToClean   = panic "defaultDynFlags: No filesToClean",
        dirsToClean    = panic "defaultDynFlags: No dirsToClean",
        generatedDumps = panic "defaultDynFlags: No generatedDumps",
        ghcVersionFile = Nothing,
        haddockOptions = Nothing,
        dumpFlags = EnumSet.empty,
        generalFlags = EnumSet.fromList (defaultFlags mySettings),
        warningFlags = EnumSet.fromList standardWarnings,
        fatalWarningFlags = EnumSet.empty,
        ghciScripts = [],
        language = Nothing,
        safeHaskell = Sf_None,
        safeInfer   = True,
        safeInferred = True,
        thOnLoc = noSrcSpan,
        newDerivOnLoc = noSrcSpan,
        overlapInstLoc = noSrcSpan,
        incoherentOnLoc = noSrcSpan,
        pkgTrustOnLoc = noSrcSpan,
        warnSafeOnLoc = noSrcSpan,
        warnUnsafeOnLoc = noSrcSpan,
        trustworthyOnLoc = noSrcSpan,
        extensions = [],
        extensionFlags = flattenExtensionFlags Nothing [],

        -- The ufCreationThreshold threshold must be reasonably high to
        -- take account of possible discounts.
        -- E.g. 450 is not enough in 'fulsom' for Interval.sqr to inline
        -- into Csg.calc (The unfolding for sqr never makes it into the
        -- interface file.)
        ufCreationThreshold = 750,
        ufUseThreshold      = 60,
        ufFunAppDiscount    = 60,
        -- Be fairly keen to inline a function if that means
        -- we'll be able to pick the right method from a dictionary
        ufDictDiscount      = 30,
        ufKeenessFactor     = 1.5,
        ufDearOp            = 40,
        ufVeryAggressive    = False,

        maxWorkerArgs = 10,

        ghciHistSize = 50, -- keep a log of length 50 by default

        -- Logging

        log_action = defaultLogAction,

        flushOut = defaultFlushOut,
        flushErr = defaultFlushErr,
        pprUserLength = 5,
        pprCols = 100,
        useUnicode = False,
        useColor = Auto,
        canUseColor = False,
        colScheme = Col.defaultScheme,
        profAuto = NoProfAuto,
        interactivePrint = Nothing,
        nextWrapperNum = panic "defaultDynFlags: No nextWrapperNum",
        sseVersion = Nothing,
        bmiVersion = Nothing,
        avx = False,
        avx2 = False,
        avx512cd = False,
        avx512er = False,
        avx512f = False,
        avx512pf = False,
        rtldInfo = panic "defaultDynFlags: no rtldInfo",
        rtccInfo = panic "defaultDynFlags: no rtccInfo",

        maxInlineAllocSize = 128,
        maxInlineMemcpyInsns = 32,
        maxInlineMemsetInsns = 32,

        initialUnique = 0,
        uniqueIncrement = 1,

        reverseErrors = False,
        maxErrors     = Nothing,
        cfgWeightInfo = defaultCfgWeights
      }

defaultWays :: Settings -> [Way]
defaultWays settings = if pc_DYNAMIC_BY_DEFAULT (sPlatformConstants settings)
                       then [WayDyn]
                       else []

interpWays :: [Way]
interpWays
  | dynamicGhc = [WayDyn]
  | rtsIsProfiled = [WayProf]
  | otherwise = []

interpreterProfiled :: DynFlags -> Bool
interpreterProfiled dflags
  | gopt Opt_ExternalInterpreter dflags = gopt Opt_SccProfilingOn dflags
  | otherwise = rtsIsProfiled

interpreterDynamic :: DynFlags -> Bool
interpreterDynamic dflags
  | gopt Opt_ExternalInterpreter dflags = WayDyn `elem` ways dflags
  | otherwise = dynamicGhc

--------------------------------------------------------------------------
--
-- Note [JSON Error Messages]
--
-- When the user requests the compiler output to be dumped as json
-- we used to collect them all in an IORef and then print them at the end.
-- This doesn't work very well with GHCi. (See #14078) So instead we now
-- use the simpler method of just outputting a JSON document inplace to
-- stdout.
--
-- Before the compiler calls log_action, it has already turned the `ErrMsg`
-- into a formatted message. This means that we lose some possible
-- information to provide to the user but refactoring log_action is quite
-- invasive as it is called in many places. So, for now I left it alone
-- and we can refine its behaviour as users request different output.

type FatalMessager = String -> IO ()

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

defaultFatalMessager :: FatalMessager
defaultFatalMessager = hPutStrLn stderr


-- See Note [JSON Error Messages]
--
jsonLogAction :: LogAction
jsonLogAction dflags reason severity srcSpan _style msg
  = do
    defaultLogActionHPutStrDoc dflags stdout (doc $$ text "")
                               (mkCodeStyle CStyle)
    where
      doc = renderJSON $
              JSObject [ ( "span", json srcSpan )
                       , ( "doc" , JSString (showSDoc dflags msg) )
                       , ( "severity", json severity )
                       , ( "reason" ,   json reason )
                       ]


defaultLogAction :: LogAction
defaultLogAction dflags reason severity srcSpan style msg
    = case severity of
      SevOutput      -> printOut msg style
      SevDump        -> printOut (msg $$ blankLine) style
      SevInteractive -> putStrSDoc msg style
      SevInfo        -> printErrs msg style
      SevFatal       -> printErrs msg style
      SevWarning     -> printWarns
      SevError       -> printWarns
    where
      printOut   = defaultLogActionHPrintDoc  dflags stdout
      printErrs  = defaultLogActionHPrintDoc  dflags stderr
      putStrSDoc = defaultLogActionHPutStrDoc dflags stdout
      -- Pretty print the warning flag, if any (#10752)
      message = mkLocMessageAnn flagMsg severity srcSpan msg

      printWarns = do
        hPutChar stderr '\n'
        caretDiagnostic <-
            if gopt Opt_DiagnosticsShowCaret dflags
            then getCaretDiagnostic severity srcSpan
            else pure empty
        printErrs (message $+$ caretDiagnostic)
            (setStyleColoured True style)
        -- careful (#2302): printErrs prints in UTF-8,
        -- whereas converting to string first and using
        -- hPutStr would just emit the low 8 bits of
        -- each unicode char.

      flagMsg =
        case reason of
          NoReason -> Nothing
          Reason wflag -> do
            spec <- flagSpecOf wflag
            return ("-W" ++ flagSpecName spec ++ warnFlagGrp wflag)
          ErrReason Nothing ->
            return "-Werror"
          ErrReason (Just wflag) -> do
            spec <- flagSpecOf wflag
            return $
              "-W" ++ flagSpecName spec ++ warnFlagGrp wflag ++
              ", -Werror=" ++ flagSpecName spec

      warnFlagGrp flag
          | gopt Opt_ShowWarnGroups dflags =
                case smallestGroups flag of
                    [] -> ""
                    groups -> " (in " ++ intercalate ", " (map ("-W"++) groups) ++ ")"
          | otherwise = ""

-- | Like 'defaultLogActionHPutStrDoc' but appends an extra newline.
defaultLogActionHPrintDoc :: DynFlags -> Handle -> SDoc -> PprStyle -> IO ()
defaultLogActionHPrintDoc dflags h d sty
 = defaultLogActionHPutStrDoc dflags h (d $$ text "") sty

defaultLogActionHPutStrDoc :: DynFlags -> Handle -> SDoc -> PprStyle -> IO ()
defaultLogActionHPutStrDoc dflags h d sty
  -- Don't add a newline at the end, so that successive
  -- calls to this log-action can output all on the same line
  = printSDoc Pretty.PageMode dflags h sty d

newtype FlushOut = FlushOut (IO ())

defaultFlushOut :: FlushOut
defaultFlushOut = FlushOut $ hFlush stdout

newtype FlushErr = FlushErr (IO ())

defaultFlushErr :: FlushErr
defaultFlushErr = FlushErr $ hFlush stderr

{-
Note [Verbosity levels]
~~~~~~~~~~~~~~~~~~~~~~~
    0   |   print errors & warnings only
    1   |   minimal verbosity: print "compiling M ... done." for each module.
    2   |   equivalent to -dshow-passes
    3   |   equivalent to existing "ghc -v"
    4   |   "ghc -v -ddump-most"
    5   |   "ghc -v -ddump-all"
-}

data OnOff a = On a
             | Off a
  deriving (Eq, Show)

instance Outputable a => Outputable (OnOff a) where
  ppr (On x)  = text "On" <+> ppr x
  ppr (Off x) = text "Off" <+> ppr x

-- OnOffs accumulate in reverse order, so we use foldr in order to
-- process them in the right order
flattenExtensionFlags :: Maybe Language -> [OnOff LangExt.Extension] -> EnumSet LangExt.Extension
flattenExtensionFlags ml = foldr f defaultExtensionFlags
    where f (On f)  flags = EnumSet.insert f flags
          f (Off f) flags = EnumSet.delete f flags
          defaultExtensionFlags = EnumSet.fromList (languageExtensions ml)

languageExtensions :: Maybe Language -> [LangExt.Extension]

languageExtensions Nothing
    -- Nothing => the default case
    = LangExt.NondecreasingIndentation -- This has been on by default for some time
    : delete LangExt.DatatypeContexts  -- The Haskell' committee decided to
                                       -- remove datatype contexts from the
                                       -- language:
   -- http://www.haskell.org/pipermail/haskell-prime/2011-January/003335.html
      (languageExtensions (Just Haskell2010))

   -- NB: MonoPatBinds is no longer the default

languageExtensions (Just Haskell98)
    = [LangExt.ImplicitPrelude,
       -- See Note [When is StarIsType enabled]
       LangExt.StarIsType,
       LangExt.CUSKs,
       LangExt.MonomorphismRestriction,
       LangExt.NPlusKPatterns,
       LangExt.DatatypeContexts,
       LangExt.TraditionalRecordSyntax,
       LangExt.NondecreasingIndentation
           -- strictly speaking non-standard, but we always had this
           -- on implicitly before the option was added in 7.1, and
           -- turning it off breaks code, so we're keeping it on for
           -- backwards compatibility.  Cabal uses -XHaskell98 by
           -- default unless you specify another language.
      ]

languageExtensions (Just Haskell2010)
    = [LangExt.ImplicitPrelude,
       -- See Note [When is StarIsType enabled]
       LangExt.StarIsType,
       LangExt.CUSKs,
       LangExt.MonomorphismRestriction,
       LangExt.DatatypeContexts,
       LangExt.TraditionalRecordSyntax,
       LangExt.EmptyDataDecls,
       LangExt.ForeignFunctionInterface,
       LangExt.PatternGuards,
       LangExt.DoAndIfThenElse,
       LangExt.RelaxedPolyRec]

hasPprDebug :: DynFlags -> Bool
hasPprDebug = dopt Opt_D_ppr_debug

hasNoDebugOutput :: DynFlags -> Bool
hasNoDebugOutput = dopt Opt_D_no_debug_output

hasNoStateHack :: DynFlags -> Bool
hasNoStateHack = gopt Opt_G_NoStateHack

hasNoOptCoercion :: DynFlags -> Bool
hasNoOptCoercion = gopt Opt_G_NoOptCoercion


-- | Test whether a 'DumpFlag' is set
dopt :: DumpFlag -> DynFlags -> Bool
dopt f dflags = (f `EnumSet.member` dumpFlags dflags)
             || (verbosity dflags >= 4 && enableIfVerbose f)
    where enableIfVerbose Opt_D_dump_tc_trace               = False
          enableIfVerbose Opt_D_dump_rn_trace               = False
          enableIfVerbose Opt_D_dump_cs_trace               = False
          enableIfVerbose Opt_D_dump_if_trace               = False
          enableIfVerbose Opt_D_dump_vt_trace               = False
          enableIfVerbose Opt_D_dump_tc                     = False
          enableIfVerbose Opt_D_dump_rn                     = False
          enableIfVerbose Opt_D_dump_shape                  = False
          enableIfVerbose Opt_D_dump_rn_stats               = False
          enableIfVerbose Opt_D_dump_hi_diffs               = False
          enableIfVerbose Opt_D_verbose_core2core           = False
          enableIfVerbose Opt_D_verbose_stg2stg             = False
          enableIfVerbose Opt_D_dump_splices                = False
          enableIfVerbose Opt_D_th_dec_file                 = False
          enableIfVerbose Opt_D_dump_rule_firings           = False
          enableIfVerbose Opt_D_dump_rule_rewrites          = False
          enableIfVerbose Opt_D_dump_simpl_trace            = False
          enableIfVerbose Opt_D_dump_rtti                   = False
          enableIfVerbose Opt_D_dump_inlinings              = False
          enableIfVerbose Opt_D_dump_core_stats             = False
          enableIfVerbose Opt_D_dump_asm_stats              = False
          enableIfVerbose Opt_D_dump_types                  = False
          enableIfVerbose Opt_D_dump_simpl_iterations       = False
          enableIfVerbose Opt_D_dump_ticked                 = False
          enableIfVerbose Opt_D_dump_view_pattern_commoning = False
          enableIfVerbose Opt_D_dump_mod_cycles             = False
          enableIfVerbose Opt_D_dump_mod_map                = False
          enableIfVerbose Opt_D_dump_ec_trace               = False
          enableIfVerbose _                                 = True

-- | Set a 'DumpFlag'
dopt_set :: DynFlags -> DumpFlag -> DynFlags
dopt_set dfs f = dfs{ dumpFlags = EnumSet.insert f (dumpFlags dfs) }

-- | Unset a 'DumpFlag'
dopt_unset :: DynFlags -> DumpFlag -> DynFlags
dopt_unset dfs f = dfs{ dumpFlags = EnumSet.delete f (dumpFlags dfs) }

-- | Test whether a 'GeneralFlag' is set
gopt :: GeneralFlag -> DynFlags -> Bool
gopt f dflags  = f `EnumSet.member` generalFlags dflags

-- | Set a 'GeneralFlag'
gopt_set :: DynFlags -> GeneralFlag -> DynFlags
gopt_set dfs f = dfs{ generalFlags = EnumSet.insert f (generalFlags dfs) }

-- | Unset a 'GeneralFlag'
gopt_unset :: DynFlags -> GeneralFlag -> DynFlags
gopt_unset dfs f = dfs{ generalFlags = EnumSet.delete f (generalFlags dfs) }

-- | Test whether a 'WarningFlag' is set
wopt :: WarningFlag -> DynFlags -> Bool
wopt f dflags  = f `EnumSet.member` warningFlags dflags

-- | Set a 'WarningFlag'
wopt_set :: DynFlags -> WarningFlag -> DynFlags
wopt_set dfs f = dfs{ warningFlags = EnumSet.insert f (warningFlags dfs) }

-- | Unset a 'WarningFlag'
wopt_unset :: DynFlags -> WarningFlag -> DynFlags
wopt_unset dfs f = dfs{ warningFlags = EnumSet.delete f (warningFlags dfs) }

-- | Test whether a 'WarningFlag' is set as fatal
wopt_fatal :: WarningFlag -> DynFlags -> Bool
wopt_fatal f dflags = f `EnumSet.member` fatalWarningFlags dflags

-- | Mark a 'WarningFlag' as fatal (do not set the flag)
wopt_set_fatal :: DynFlags -> WarningFlag -> DynFlags
wopt_set_fatal dfs f
    = dfs { fatalWarningFlags = EnumSet.insert f (fatalWarningFlags dfs) }

-- | Mark a 'WarningFlag' as not fatal
wopt_unset_fatal :: DynFlags -> WarningFlag -> DynFlags
wopt_unset_fatal dfs f
    = dfs { fatalWarningFlags = EnumSet.delete f (fatalWarningFlags dfs) }

-- | Test whether a 'LangExt.Extension' is set
xopt :: LangExt.Extension -> DynFlags -> Bool
xopt f dflags = f `EnumSet.member` extensionFlags dflags

-- | Set a 'LangExt.Extension'
xopt_set :: DynFlags -> LangExt.Extension -> DynFlags
xopt_set dfs f
    = let onoffs = On f : extensions dfs
      in dfs { extensions = onoffs,
               extensionFlags = flattenExtensionFlags (language dfs) onoffs }

-- | Unset a 'LangExt.Extension'
xopt_unset :: DynFlags -> LangExt.Extension -> DynFlags
xopt_unset dfs f
    = let onoffs = Off f : extensions dfs
      in dfs { extensions = onoffs,
               extensionFlags = flattenExtensionFlags (language dfs) onoffs }

-- | Set or unset a 'LangExt.Extension', unless it has been explicitly
--   set or unset before.
xopt_set_unlessExplSpec
        :: LangExt.Extension
        -> (DynFlags -> LangExt.Extension -> DynFlags)
        -> DynFlags -> DynFlags
xopt_set_unlessExplSpec ext setUnset dflags =
    let referedExts = stripOnOff <$> extensions dflags
        stripOnOff (On x)  = x
        stripOnOff (Off x) = x
    in
        if ext `elem` referedExts then dflags else setUnset dflags ext

lang_set :: DynFlags -> Maybe Language -> DynFlags
lang_set dflags lang =
   dflags {
            language = lang,
            extensionFlags = flattenExtensionFlags lang (extensions dflags)
          }

-- | An internal helper to check whether to use unicode syntax for output.
--
-- Note: You should very likely be using 'Outputable.unicodeSyntax' instead
-- of this function.
useUnicodeSyntax :: DynFlags -> Bool
useUnicodeSyntax = gopt Opt_PrintUnicodeSyntax

useStarIsType :: DynFlags -> Bool
useStarIsType = xopt LangExt.StarIsType

-- | Set the Haskell language standard to use
setLanguage :: Language -> DynP ()
setLanguage l = upd (`lang_set` Just l)

-- | Some modules have dependencies on others through the DynFlags rather than textual imports
dynFlagDependencies :: DynFlags -> [ModuleName]
dynFlagDependencies = pluginModNames

-- | Is the -fpackage-trust mode on
packageTrustOn :: DynFlags -> Bool
packageTrustOn = gopt Opt_PackageTrust

-- | Is Safe Haskell on in some way (including inference mode)
safeHaskellOn :: DynFlags -> Bool
safeHaskellOn dflags = safeHaskellModeEnabled dflags || safeInferOn dflags

safeHaskellModeEnabled :: DynFlags -> Bool
safeHaskellModeEnabled dflags = safeHaskell dflags `elem` [Sf_Unsafe, Sf_Trustworthy
                                                   , Sf_Safe ]


-- | Is the Safe Haskell safe language in use
safeLanguageOn :: DynFlags -> Bool
safeLanguageOn dflags = safeHaskell dflags == Sf_Safe

-- | Is the Safe Haskell safe inference mode active
safeInferOn :: DynFlags -> Bool
safeInferOn = safeInfer

-- | Test if Safe Imports are on in some form
safeImportsOn :: DynFlags -> Bool
safeImportsOn dflags = safeHaskell dflags == Sf_Unsafe ||
                       safeHaskell dflags == Sf_Trustworthy ||
                       safeHaskell dflags == Sf_Safe

-- | Set a 'Safe Haskell' flag
setSafeHaskell :: SafeHaskellMode -> DynP ()
setSafeHaskell s = updM f
    where f dfs = do
              let sf = safeHaskell dfs
              safeM <- combineSafeFlags sf s
              case s of
                Sf_Safe -> return $ dfs { safeHaskell = safeM, safeInfer = False }
                -- leave safe inferrence on in Trustworthy mode so we can warn
                -- if it could have been inferred safe.
                Sf_Trustworthy -> do
                  l <- getCurLoc
                  return $ dfs { safeHaskell = safeM, trustworthyOnLoc = l }
                -- leave safe inference on in Unsafe mode as well.
                _ -> return $ dfs { safeHaskell = safeM }

-- | Are all direct imports required to be safe for this Safe Haskell mode?
-- Direct imports are when the code explicitly imports a module
safeDirectImpsReq :: DynFlags -> Bool
safeDirectImpsReq d = safeLanguageOn d

-- | Are all implicit imports required to be safe for this Safe Haskell mode?
-- Implicit imports are things in the prelude. e.g System.IO when print is used.
safeImplicitImpsReq :: DynFlags -> Bool
safeImplicitImpsReq d = safeLanguageOn d

-- | Combine two Safe Haskell modes correctly. Used for dealing with multiple flags.
-- This makes Safe Haskell very much a monoid but for now I prefer this as I don't
-- want to export this functionality from the module but do want to export the
-- type constructors.
combineSafeFlags :: SafeHaskellMode -> SafeHaskellMode -> DynP SafeHaskellMode
combineSafeFlags a b | a == Sf_None         = return b
                     | b == Sf_None         = return a
                     | a == Sf_Ignore || b == Sf_Ignore = return Sf_Ignore
                     | a == b               = return a
                     | otherwise            = addErr errm >> pure a
    where errm = "Incompatible Safe Haskell flags! ("
                    ++ show a ++ ", " ++ show b ++ ")"

-- | A list of unsafe flags under Safe Haskell. Tuple elements are:
--     * name of the flag
--     * function to get srcspan that enabled the flag
--     * function to test if the flag is on
--     * function to turn the flag off
unsafeFlags, unsafeFlagsForInfer
  :: [(String, DynFlags -> SrcSpan, DynFlags -> Bool, DynFlags -> DynFlags)]
unsafeFlags = [ ("-XGeneralizedNewtypeDeriving", newDerivOnLoc,
                    xopt LangExt.GeneralizedNewtypeDeriving,
                    flip xopt_unset LangExt.GeneralizedNewtypeDeriving)
              , ("-XTemplateHaskell", thOnLoc,
                    xopt LangExt.TemplateHaskell,
                    flip xopt_unset LangExt.TemplateHaskell)
              ]
unsafeFlagsForInfer = unsafeFlags


-- | Retrieve the options corresponding to a particular @opt_*@ field in the correct order
getOpts :: DynFlags             -- ^ 'DynFlags' to retrieve the options from
        -> (DynFlags -> [a])    -- ^ Relevant record accessor: one of the @opt_*@ accessors
        -> [a]                  -- ^ Correctly ordered extracted options
getOpts dflags opts = reverse (opts dflags)
        -- We add to the options from the front, so we need to reverse the list

-- | Gets the verbosity flag for the current verbosity level. This is fed to
-- other tools, so GHC-specific verbosity flags like @-ddump-most@ are not included
getVerbFlags :: DynFlags -> [String]
getVerbFlags dflags
  | verbosity dflags >= 4 = ["-v"]
  | otherwise             = []

setObjectDir, setHiDir, setHieDir, setStubDir, setDumpDir, setOutputDir,
         setDynObjectSuf, setDynHiSuf,
         setDylibInstallName,
         setObjectSuf, setHiSuf, setHieSuf, setHcSuf, parseDynLibLoaderMode,
         setPgmP, addOptl, addOptc, addOptcxx, addOptP,
         addCmdlineFramework, addHaddockOpts, addGhciScript,
         setInteractivePrint
   :: String -> DynFlags -> DynFlags
setOutputFile, setDynOutputFile, setOutputHi, setDumpPrefixForce
   :: Maybe String -> DynFlags -> DynFlags

setObjectDir  f d = d { objectDir  = Just f}
setHiDir      f d = d { hiDir      = Just f}
setHieDir     f d = d { hieDir     = Just f}
setStubDir    f d = d { stubDir    = Just f
                      , includePaths = addGlobalInclude (includePaths d) [f] }
  -- -stubdir D adds an implicit -I D, so that gcc can find the _stub.h file
  -- \#included from the .hc file when compiling via C (i.e. unregisterised
  -- builds).
setDumpDir    f d = d { dumpDir    = Just f}
setOutputDir  f = setObjectDir f
                . setHieDir f
                . setHiDir f
                . setStubDir f
                . setDumpDir f
setDylibInstallName  f d = d { dylibInstallName = Just f}

setObjectSuf    f d = d { objectSuf    = f}
setDynObjectSuf f d = d { dynObjectSuf = f}
setHiSuf        f d = d { hiSuf        = f}
setHieSuf       f d = d { hieSuf       = f}
setDynHiSuf     f d = d { dynHiSuf     = f}
setHcSuf        f d = d { hcSuf        = f}

setOutputFile f d = d { outputFile = f}
setDynOutputFile f d = d { dynOutputFile = f}
setOutputHi   f d = d { outputHi   = f}

setJsonLogAction :: DynFlags -> DynFlags
setJsonLogAction d = d { log_action = jsonLogAction }

thisComponentId :: DynFlags -> ComponentId
thisComponentId dflags =
  case thisComponentId_ dflags of
    Just cid -> cid
    Nothing  ->
      case thisUnitIdInsts_ dflags of
        Just _  ->
          throwGhcException $ CmdLineError ("Use of -instantiated-with requires -this-component-id")
        Nothing -> ComponentId (unitIdFS (thisPackage dflags))

thisUnitIdInsts :: DynFlags -> [(ModuleName, Module)]
thisUnitIdInsts dflags =
    case thisUnitIdInsts_ dflags of
        Just insts -> insts
        Nothing    -> []

thisPackage :: DynFlags -> UnitId
thisPackage dflags =
    case thisUnitIdInsts_ dflags of
        Nothing -> default_uid
        Just insts
          | all (\(x,y) -> mkHoleModule x == y) insts
          -> newUnitId (thisComponentId dflags) insts
          | otherwise
          -> default_uid
  where
    default_uid = DefiniteUnitId (DefUnitId (thisInstalledUnitId dflags))

parseUnitIdInsts :: String -> [(ModuleName, Module)]
parseUnitIdInsts str = case filter ((=="").snd) (readP_to_S parse str) of
    [(r, "")] -> r
    _ -> throwGhcException $ CmdLineError ("Can't parse -instantiated-with: " ++ str)
  where parse = sepBy parseEntry (R.char ',')
        parseEntry = do
            n <- parseModuleName
            _ <- R.char '='
            m <- parseModuleId
            return (n, m)

setUnitIdInsts :: String -> DynFlags -> DynFlags
setUnitIdInsts s d =
    d { thisUnitIdInsts_ = Just (parseUnitIdInsts s) }

setComponentId :: String -> DynFlags -> DynFlags
setComponentId s d =
    d { thisComponentId_ = Just (ComponentId (fsLit s)) }

addPluginModuleName :: String -> DynFlags -> DynFlags
addPluginModuleName name d = d { pluginModNames = (mkModuleName name) : (pluginModNames d) }

clearPluginModuleNames :: DynFlags -> DynFlags
clearPluginModuleNames d =
    d { pluginModNames = []
      , pluginModNameOpts = []
      , cachedPlugins = [] }

addPluginModuleNameOption :: String -> DynFlags -> DynFlags
addPluginModuleNameOption optflag d = d { pluginModNameOpts = (mkModuleName m, option) : (pluginModNameOpts d) }
  where (m, rest) = break (== ':') optflag
        option = case rest of
          [] -> "" -- should probably signal an error
          (_:plug_opt) -> plug_opt -- ignore the ':' from break

addFrontendPluginOption :: String -> DynFlags -> DynFlags
addFrontendPluginOption s d = d { frontendPluginOpts = s : frontendPluginOpts d }

parseDynLibLoaderMode f d =
 case splitAt 8 f of
   ("deploy", "")       -> d { dynLibLoader = Deployable }
   ("sysdep", "")       -> d { dynLibLoader = SystemDependent }
   _                    -> throwGhcException (CmdLineError ("Unknown dynlib loader: " ++ f))

setDumpPrefixForce f d = d { dumpPrefixForce = f}

-- XXX HACK: Prelude> words "'does not' work" ===> ["'does","not'","work"]
-- Config.hs should really use Option.
setPgmP   f = let (pgm:args) = words f in alterSettings (\s -> s { sPgm_P   = (pgm, map Option args)})
addOptl   f = alterSettings (\s -> s { sOpt_l   = f : sOpt_l s})
addOptc   f = alterSettings (\s -> s { sOpt_c   = f : sOpt_c s})
addOptcxx f = alterSettings (\s -> s { sOpt_cxx = f : sOpt_cxx s})
addOptP   f = alterSettings (\s -> s { sOpt_P   = f : sOpt_P s
                                     , sOpt_P_fingerprint = fingerprintStrings (f : sOpt_P s)
                                     })
                                     -- See Note [Repeated -optP hashing]
  where
  fingerprintStrings ss = fingerprintFingerprints $ map fingerprintString ss


setDepMakefile :: FilePath -> DynFlags -> DynFlags
setDepMakefile f d = d { depMakefile = f }

setDepIncludeCppDeps :: Bool -> DynFlags -> DynFlags
setDepIncludeCppDeps b d = d { depIncludeCppDeps = b }

setDepIncludePkgDeps :: Bool -> DynFlags -> DynFlags
setDepIncludePkgDeps b d = d { depIncludePkgDeps = b }

addDepExcludeMod :: String -> DynFlags -> DynFlags
addDepExcludeMod m d
    = d { depExcludeMods = mkModuleName m : depExcludeMods d }

addDepSuffix :: FilePath -> DynFlags -> DynFlags
addDepSuffix s d = d { depSuffixes = s : depSuffixes d }

addCmdlineFramework f d = d { cmdlineFrameworks = f : cmdlineFrameworks d}

addGhcVersionFile :: FilePath -> DynFlags -> DynFlags
addGhcVersionFile f d = d { ghcVersionFile = Just f }

addHaddockOpts f d = d { haddockOptions = Just f}

addGhciScript f d = d { ghciScripts = f : ghciScripts d}

setInteractivePrint f d = d { interactivePrint = Just f}

-- -----------------------------------------------------------------------------
-- Command-line options

-- | When invoking external tools as part of the compilation pipeline, we
-- pass these a sequence of options on the command-line. Rather than
-- just using a list of Strings, we use a type that allows us to distinguish
-- between filepaths and 'other stuff'. The reason for this is that
-- this type gives us a handle on transforming filenames, and filenames only,
-- to whatever format they're expected to be on a particular platform.
data Option
 = FileOption -- an entry that _contains_ filename(s) / filepaths.
              String  -- a non-filepath prefix that shouldn't be
                      -- transformed (e.g., "/out=")
              String  -- the filepath/filename portion
 | Option     String
 deriving ( Eq )

showOpt :: Option -> String
showOpt (FileOption pre f) = pre ++ f
showOpt (Option s)  = s

-----------------------------------------------------------------------------
-- Setting the optimisation level

updOptLevel :: Int -> DynFlags -> DynFlags
-- ^ Sets the 'DynFlags' to be appropriate to the optimisation level
updOptLevel n dfs
  = dfs2{ optLevel = final_n }
  where
   final_n = max 0 (min 2 n)    -- Clamp to 0 <= n <= 2
   dfs1 = foldr (flip gopt_unset) dfs  remove_gopts
   dfs2 = foldr (flip gopt_set)   dfs1 extra_gopts

   extra_gopts  = [ f | (ns,f) <- optLevelFlags, final_n `elem` ns ]
   remove_gopts = [ f | (ns,f) <- optLevelFlags, final_n `notElem` ns ]

{- **********************************************************************
%*                                                                      *
                DynFlags parser
%*                                                                      *
%********************************************************************* -}

-- -----------------------------------------------------------------------------
-- Parsing the dynamic flags.


-- | Parse dynamic flags from a list of command line arguments.  Returns the
-- the parsed 'DynFlags', the left-over arguments, and a list of warnings.
-- Throws a 'UsageError' if errors occurred during parsing (such as unknown
-- flags or missing arguments).
parseDynamicFlagsCmdLine :: MonadIO m => DynFlags -> [Located String]
                         -> m (DynFlags, [Located String], [Warn])
                            -- ^ Updated 'DynFlags', left-over arguments, and
                            -- list of warnings.
parseDynamicFlagsCmdLine = parseDynamicFlagsFull flagsAll True


-- | Like 'parseDynamicFlagsCmdLine' but does not allow the package flags
-- (-package, -hide-package, -ignore-package, -hide-all-packages, -package-db).
-- Used to parse flags set in a modules pragma.
parseDynamicFilePragma :: MonadIO m => DynFlags -> [Located String]
                       -> m (DynFlags, [Located String], [Warn])
                          -- ^ Updated 'DynFlags', left-over arguments, and
                          -- list of warnings.
parseDynamicFilePragma = parseDynamicFlagsFull flagsDynamic False


-- | Parses the dynamically set flags for GHC. This is the most general form of
-- the dynamic flag parser that the other methods simply wrap. It allows
-- saying which flags are valid flags and indicating if we are parsing
-- arguments from the command line or from a file pragma.
parseDynamicFlagsFull :: MonadIO m
                  => [Flag (CmdLineP DynFlags)]    -- ^ valid flags to match against
                  -> Bool                          -- ^ are the arguments from the command line?
                  -> DynFlags                      -- ^ current dynamic flags
                  -> [Located String]              -- ^ arguments to parse
                  -> m (DynFlags, [Located String], [Warn])
parseDynamicFlagsFull activeFlags cmdline dflags0 args = do
  let ((leftover, errs, warns), dflags1)
          = runCmdLine (processArgs activeFlags args) dflags0

  -- See Note [Handling errors when parsing commandline flags]
  unless (null errs) $ liftIO $ throwGhcExceptionIO $ errorsToGhcException $
    map ((showPpr dflags0 . getLoc &&& unLoc) . errMsg) $ errs

  -- check for disabled flags in safe haskell
  let (dflags2, sh_warns) = safeFlagCheck cmdline dflags1
      dflags3 = updateWays dflags2
      theWays = ways dflags3

  unless (allowed_combination theWays) $ liftIO $
      throwGhcExceptionIO (CmdLineError ("combination not supported: " ++
                               intercalate "/" (map wayDesc theWays)))

  let chooseOutput
        | isJust (outputFile dflags3)          -- Only iff user specified -o ...
        , not (isJust (dynOutputFile dflags3)) -- but not -dyno
        = return $ dflags3 { dynOutputFile = Just $ dynamicOutputFile dflags3 outFile }
        | otherwise
        = return dflags3
        where
          outFile = fromJust $ outputFile dflags3
  dflags4 <- ifGeneratingDynamicToo dflags3 chooseOutput (return dflags3)

  let (dflags5, consistency_warnings) = makeDynFlagsConsistent dflags4

  -- Set timer stats & heap size
  when (enableTimeStats dflags5) $ liftIO enableTimingStats
  case (ghcHeapSize dflags5) of
    Just x -> liftIO (setHeapSize x)
    _      -> return ()

  liftIO $ setUnsafeGlobalDynFlags dflags5

  let warns' = map (Warn Cmd.NoReason) (consistency_warnings ++ sh_warns)

  return (dflags5, leftover, warns' ++ warns)

-- | Write an error or warning to the 'LogOutput'.
putLogMsg :: DynFlags -> WarnReason -> Severity -> SrcSpan -> PprStyle
          -> MsgDoc -> IO ()
putLogMsg dflags = log_action dflags dflags

updateWays :: DynFlags -> DynFlags
updateWays dflags
    = let theWays = sort $ nub $ ways dflags
      in dflags {
             ways        = theWays,
             buildTag    = mkBuildTag (filter (not . wayRTSOnly) theWays)
         }

-- | Check (and potentially disable) any extensions that aren't allowed
-- in safe mode.
--
-- The bool is to indicate if we are parsing command line flags (false means
-- file pragma). This allows us to generate better warnings.
safeFlagCheck :: Bool -> DynFlags -> (DynFlags, [Located String])
safeFlagCheck _ dflags | safeLanguageOn dflags = (dflagsUnset, warns)
  where
    -- Handle illegal flags under safe language.
    (dflagsUnset, warns) = foldl' check_method (dflags, []) unsafeFlags

    check_method (df, warns) (str,loc,test,fix)
        | test df   = (fix df, warns ++ safeFailure (loc df) str)
        | otherwise = (df, warns)

    safeFailure loc str
       = [L loc $ str ++ " is not allowed in Safe Haskell; ignoring "
           ++ str]

safeFlagCheck cmdl dflags =
  case (safeInferOn dflags) of
    True | safeFlags -> (dflags', warn)
    True             -> (dflags' { safeInferred = False }, warn)
    False            -> (dflags', warn)

  where
    -- dynflags and warn for when -fpackage-trust by itself with no safe
    -- haskell flag
    (dflags', warn)
      | not (safeHaskellModeEnabled dflags) && not cmdl && packageTrustOn dflags
      = (gopt_unset dflags Opt_PackageTrust, pkgWarnMsg)
      | otherwise = (dflags, [])

    pkgWarnMsg = [L (pkgTrustOnLoc dflags') $
                    "-fpackage-trust ignored;" ++
                    " must be specified with a Safe Haskell flag"]

    -- Have we inferred Unsafe? See Note [HscMain . Safe Haskell Inference]
    safeFlags = all (\(_,_,t,_) -> not $ t dflags) unsafeFlagsForInfer


{- **********************************************************************
%*                                                                      *
                DynFlags specifications
%*                                                                      *
%********************************************************************* -}

-- | All dynamic flags option strings without the deprecated ones.
-- These are the user facing strings for enabling and disabling options.
allNonDeprecatedFlags :: [String]
allNonDeprecatedFlags = allFlagsDeps False

-- | All flags with possibility to filter deprecated ones
allFlagsDeps :: Bool -> [String]
allFlagsDeps keepDeprecated = [ '-':flagName flag
                              | (deprecated, flag) <- flagsAllDeps
                              , keepDeprecated || not (isDeprecated deprecated)]
  where isDeprecated Deprecated = True
        isDeprecated _ = False

{-
 - Below we export user facing symbols for GHC dynamic flags for use with the
 - GHC API.
 -}

-- All dynamic flags present in GHC.
flagsAll :: [Flag (CmdLineP DynFlags)]
flagsAll = map snd flagsAllDeps

-- All dynamic flags present in GHC with deprecation information.
flagsAllDeps :: [(Deprecation, Flag (CmdLineP DynFlags))]
flagsAllDeps =  package_flags_deps ++ dynamic_flags_deps


-- All dynamic flags, minus package flags, present in GHC.
flagsDynamic :: [Flag (CmdLineP DynFlags)]
flagsDynamic = map snd dynamic_flags_deps

-- ALl package flags present in GHC.
flagsPackage :: [Flag (CmdLineP DynFlags)]
flagsPackage = map snd package_flags_deps

----------------Helpers to make flags and keep deprecation information----------

type FlagMaker m = String -> OptKind m -> Flag m
type DynFlagMaker = FlagMaker (CmdLineP DynFlags)
data Deprecation = NotDeprecated | Deprecated deriving (Eq, Ord)

-- Make a non-deprecated flag
make_ord_flag :: DynFlagMaker -> String -> OptKind (CmdLineP DynFlags)
              -> (Deprecation, Flag (CmdLineP DynFlags))
make_ord_flag fm name kind = (NotDeprecated, fm name kind)

-- Make a deprecated flag
make_dep_flag :: DynFlagMaker -> String -> OptKind (CmdLineP DynFlags) -> String
                 -> (Deprecation, Flag (CmdLineP DynFlags))
make_dep_flag fm name kind message = (Deprecated,
                                      fm name $ add_dep_message kind message)

add_dep_message :: OptKind (CmdLineP DynFlags) -> String
                -> OptKind (CmdLineP DynFlags)
add_dep_message (NoArg f) message = NoArg $ f >> deprecate message
add_dep_message (HasArg f) message = HasArg $ \s -> f s >> deprecate message
add_dep_message (SepArg f) message = SepArg $ \s -> f s >> deprecate message
add_dep_message (Prefix f) message = Prefix $ \s -> f s >> deprecate message
add_dep_message (OptPrefix f) message =
                                  OptPrefix $ \s -> f s >> deprecate message
add_dep_message (OptIntSuffix f) message =
                               OptIntSuffix $ \oi -> f oi >> deprecate message
add_dep_message (IntSuffix f) message =
                                  IntSuffix $ \i -> f i >> deprecate message
add_dep_message (FloatSuffix f) message =
                                FloatSuffix $ \fl -> f fl >> deprecate message
add_dep_message (PassFlag f) message =
                                   PassFlag $ \s -> f s >> deprecate message
add_dep_message (AnySuffix f) message =
                                  AnySuffix $ \s -> f s >> deprecate message

----------------------- The main flags themselves ------------------------------
-- See Note [Updating flag description in the User's Guide]
-- See Note [Supporting CLI completion]
dynamic_flags_deps :: [(Deprecation, Flag (CmdLineP DynFlags))]
dynamic_flags_deps = [
    make_dep_flag defFlag "n" (NoArg $ return ())
        "The -n flag is deprecated and no longer has any effect"
  , make_ord_flag defFlag "cpp"      (NoArg (setExtensionFlag LangExt.Cpp))
  , make_ord_flag defFlag "F"        (NoArg (setGeneralFlag Opt_Pp))
  , (Deprecated, defFlag "#include"
      (HasArg (\_s ->
         deprecate ("-#include and INCLUDE pragmas are " ++
                    "deprecated: They no longer have any effect"))))
  , make_ord_flag defFlag "v"        (OptIntSuffix setVerbosity)

  , make_ord_flag defGhcFlag "j"     (OptIntSuffix
        (\n -> case n of
                 Just n
                     | n > 0     -> upd (\d -> d { parMakeCount = Just n })
                     | otherwise -> addErr "Syntax: -j[n] where n > 0"
                 Nothing -> upd (\d -> d { parMakeCount = Nothing })))
                 -- When the number of parallel builds
                 -- is omitted, it is the same
                 -- as specifing that the number of
                 -- parallel builds is equal to the
                 -- result of getNumProcessors
  , make_ord_flag defFlag "instantiated-with"   (sepArg setUnitIdInsts)
  , make_ord_flag defFlag "this-component-id"   (sepArg setComponentId)

    -- RTS options -------------------------------------------------------------
  , make_ord_flag defFlag "H"           (HasArg (\s -> upd (\d ->
          d { ghcHeapSize = Just $ fromIntegral (decodeSize s)})))

  , make_ord_flag defFlag "Rghc-timing" (NoArg (upd (\d ->
                                               d { enableTimeStats = True })))

    ------- ways ---------------------------------------------------------------
  , make_ord_flag defGhcFlag "prof"           (NoArg (addWay WayProf))
  , make_ord_flag defGhcFlag "eventlog"       (NoArg (addWay WayEventLog))
  , make_dep_flag defGhcFlag "smp"
      (NoArg $ addWay WayThreaded) "Use -threaded instead"
  , make_ord_flag defGhcFlag "debug"          (NoArg (addWay WayDebug))
  , make_ord_flag defGhcFlag "threaded"       (NoArg (addWay WayThreaded))

  , make_ord_flag defGhcFlag "ticky"
      (NoArg (setGeneralFlag Opt_Ticky >> addWay WayDebug))

    -- -ticky enables ticky-ticky code generation, and also implies -debug which
    -- is required to get the RTS ticky support.

        ----- Linker --------------------------------------------------------
  , make_ord_flag defGhcFlag "static"         (NoArg removeWayDyn)
  , make_ord_flag defGhcFlag "dynamic"        (NoArg (addWay WayDyn))
  , make_ord_flag defGhcFlag "rdynamic" $ noArg $
#if defined(linux_HOST_OS)
                              addOptl "-rdynamic"
#elif defined (mingw32_HOST_OS)
                              addOptl "-Wl,--export-all-symbols"
#else
    -- ignored for compat w/ gcc:
                              id
#endif
  , make_ord_flag defGhcFlag "relative-dynlib-paths"
      (NoArg (setGeneralFlag Opt_RelativeDynlibPaths))
  , make_ord_flag defGhcFlag "copy-libs-when-linking"
      (NoArg (setGeneralFlag Opt_SingleLibFolder))
  , make_ord_flag defGhcFlag "pie"            (NoArg (setGeneralFlag Opt_PICExecutable))
  , make_ord_flag defGhcFlag "no-pie"         (NoArg (unSetGeneralFlag Opt_PICExecutable))

        ------- Specific phases  --------------------------------------------
    -- need to appear before -pgmL to be parsed as LLVM flags.
  , make_ord_flag defFlag "pgmlo"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_lo  = (f,[])})))
  , make_ord_flag defFlag "pgmlc"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_lc  = (f,[])})))
  , make_ord_flag defFlag "pgmi"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_i  =  f})))
  , make_ord_flag defFlag "pgmL"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_L   = f})))
  , make_ord_flag defFlag "pgmP"
      (hasArg setPgmP)
  , make_ord_flag defFlag "pgmF"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_F   = f})))
  , make_ord_flag defFlag "pgmc"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_c   = (f,[]),
                                              -- Don't pass -no-pie with -pgmc
                                              -- (see #15319)
                                              sGccSupportsNoPie = False})))
  , make_ord_flag defFlag "pgms"
      (HasArg (\_ -> addWarn "Object splitting was removed in GHC 8.8"))
  , make_ord_flag defFlag "pgma"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_a   = (f,[])})))
  , make_ord_flag defFlag "pgml"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_l   = (f,[])})))
  , make_ord_flag defFlag "pgmdll"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_dll = (f,[])})))
  , make_ord_flag defFlag "pgmwindres"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_windres = f})))
  , make_ord_flag defFlag "pgmlibtool"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_libtool = f})))
  , make_ord_flag defFlag "pgmar"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_ar = f})))
  , make_ord_flag defFlag "pgmranlib"
      (hasArg (\f -> alterSettings (\s -> s { sPgm_ranlib = f})))


    -- need to appear before -optl/-opta to be parsed as LLVM flags.
  , make_ord_flag defFlag "optlo"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_lo  = f : sOpt_lo s})))
  , make_ord_flag defFlag "optlc"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_lc  = f : sOpt_lc s})))
  , make_ord_flag defFlag "opti"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_i   = f : sOpt_i s})))
  , make_ord_flag defFlag "optL"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_L   = f : sOpt_L s})))
  , make_ord_flag defFlag "optP"
      (hasArg addOptP)
  , make_ord_flag defFlag "optF"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_F   = f : sOpt_F s})))
  , make_ord_flag defFlag "optc"
      (hasArg addOptc)
  , make_ord_flag defFlag "optcxx"
      (hasArg addOptcxx)
  , make_ord_flag defFlag "opta"
      (hasArg (\f -> alterSettings (\s -> s { sOpt_a   = f : sOpt_a s})))
  , make_ord_flag defFlag "optl"
      (hasArg addOptl)
  , make_ord_flag defFlag "optwindres"
      (hasArg (\f ->
        alterSettings (\s -> s { sOpt_windres = f : sOpt_windres s})))

  , make_ord_flag defGhcFlag "split-objs"
      (NoArg $ addWarn "ignoring -split-objs")

  , make_ord_flag defGhcFlag "split-sections"
      (noArgM (\dflags -> do
        if platformHasSubsectionsViaSymbols (targetPlatform dflags)
          then do addErr $
                    "-split-sections is not useful on this platform " ++
                    "since it always uses subsections via symbols."
                  return dflags
          else return (gopt_set dflags Opt_SplitSections)))

        -------- ghc -M -----------------------------------------------------
  , make_ord_flag defGhcFlag "dep-suffix"              (hasArg addDepSuffix)
  , make_ord_flag defGhcFlag "dep-makefile"            (hasArg setDepMakefile)
  , make_ord_flag defGhcFlag "include-cpp-deps"
        (noArg (setDepIncludeCppDeps True))
  , make_ord_flag defGhcFlag "include-pkg-deps"
        (noArg (setDepIncludePkgDeps True))
  , make_ord_flag defGhcFlag "exclude-module"          (hasArg addDepExcludeMod)

        -------- Linking ----------------------------------------------------
  , make_ord_flag defGhcFlag "no-link"
        (noArg (\d -> d { ghcLink=NoLink }))
  , make_ord_flag defGhcFlag "shared"
        (noArg (\d -> d { ghcLink=LinkDynLib }))
  , make_ord_flag defGhcFlag "staticlib"
        (noArg (\d -> d { ghcLink=LinkStaticLib }))
  , make_ord_flag defGhcFlag "dynload"            (hasArg parseDynLibLoaderMode)
  , make_ord_flag defGhcFlag "dylib-install-name" (hasArg setDylibInstallName)

        ------- Libraries ---------------------------------------------------
  , make_ord_flag defFlag "L"   (Prefix addLibraryPath)
  , make_ord_flag defFlag "l"   (hasArg (addLdInputs . Option . ("-l" ++)))

        ------- Frameworks --------------------------------------------------
        -- -framework-path should really be -F ...
  , make_ord_flag defFlag "framework-path" (HasArg addFrameworkPath)
  , make_ord_flag defFlag "framework"      (hasArg addCmdlineFramework)

        ------- Output Redirection ------------------------------------------
  , make_ord_flag defGhcFlag "odir"              (hasArg setObjectDir)
  , make_ord_flag defGhcFlag "o"                 (sepArg (setOutputFile . Just))
  , make_ord_flag defGhcFlag "dyno"
        (sepArg (setDynOutputFile . Just))
  , make_ord_flag defGhcFlag "ohi"
        (hasArg (setOutputHi . Just ))
  , make_ord_flag defGhcFlag "osuf"              (hasArg setObjectSuf)
  , make_ord_flag defGhcFlag "dynosuf"           (hasArg setDynObjectSuf)
  , make_ord_flag defGhcFlag "hcsuf"             (hasArg setHcSuf)
  , make_ord_flag defGhcFlag "hisuf"             (hasArg setHiSuf)
  , make_ord_flag defGhcFlag "hiesuf"            (hasArg setHieSuf)
  , make_ord_flag defGhcFlag "dynhisuf"          (hasArg setDynHiSuf)
  , make_ord_flag defGhcFlag "hidir"             (hasArg setHiDir)
  , make_ord_flag defGhcFlag "hiedir"            (hasArg setHieDir)
  , make_ord_flag defGhcFlag "tmpdir"            (hasArg setTmpDir)
  , make_ord_flag defGhcFlag "stubdir"           (hasArg setStubDir)
  , make_ord_flag defGhcFlag "dumpdir"           (hasArg setDumpDir)
  , make_ord_flag defGhcFlag "outputdir"         (hasArg setOutputDir)
  , make_ord_flag defGhcFlag "ddump-file-prefix"
        (hasArg (setDumpPrefixForce . Just))

  , make_ord_flag defGhcFlag "dynamic-too"
        (NoArg (setGeneralFlag Opt_BuildDynamicToo))

        ------- Keeping temporary files -------------------------------------
     -- These can be singular (think ghc -c) or plural (think ghc --make)
  , make_ord_flag defGhcFlag "keep-hc-file"
        (NoArg (setGeneralFlag Opt_KeepHcFiles))
  , make_ord_flag defGhcFlag "keep-hc-files"
        (NoArg (setGeneralFlag Opt_KeepHcFiles))
  , make_ord_flag defGhcFlag "keep-hscpp-file"
        (NoArg (setGeneralFlag Opt_KeepHscppFiles))
  , make_ord_flag defGhcFlag "keep-hscpp-files"
        (NoArg (setGeneralFlag Opt_KeepHscppFiles))
  , make_ord_flag defGhcFlag "keep-s-file"
        (NoArg (setGeneralFlag Opt_KeepSFiles))
  , make_ord_flag defGhcFlag "keep-s-files"
        (NoArg (setGeneralFlag Opt_KeepSFiles))
  , make_ord_flag defGhcFlag "keep-llvm-file"
        (NoArg $ setObjTarget HscLlvm >> setGeneralFlag Opt_KeepLlvmFiles)
  , make_ord_flag defGhcFlag "keep-llvm-files"
        (NoArg $ setObjTarget HscLlvm >> setGeneralFlag Opt_KeepLlvmFiles)
     -- This only makes sense as plural
  , make_ord_flag defGhcFlag "keep-tmp-files"
        (NoArg (setGeneralFlag Opt_KeepTmpFiles))
  , make_ord_flag defGhcFlag "keep-hi-file"
        (NoArg (setGeneralFlag Opt_KeepHiFiles))
  , make_ord_flag defGhcFlag "no-keep-hi-file"
        (NoArg (unSetGeneralFlag Opt_KeepHiFiles))
  , make_ord_flag defGhcFlag "keep-hi-files"
        (NoArg (setGeneralFlag Opt_KeepHiFiles))
  , make_ord_flag defGhcFlag "no-keep-hi-files"
        (NoArg (unSetGeneralFlag Opt_KeepHiFiles))
  , make_ord_flag defGhcFlag "keep-o-file"
        (NoArg (setGeneralFlag Opt_KeepOFiles))
  , make_ord_flag defGhcFlag "no-keep-o-file"
        (NoArg (unSetGeneralFlag Opt_KeepOFiles))
  , make_ord_flag defGhcFlag "keep-o-files"
        (NoArg (setGeneralFlag Opt_KeepOFiles))
  , make_ord_flag defGhcFlag "no-keep-o-files"
        (NoArg (unSetGeneralFlag Opt_KeepOFiles))

        ------- Miscellaneous ----------------------------------------------
  , make_ord_flag defGhcFlag "no-auto-link-packages"
        (NoArg (unSetGeneralFlag Opt_AutoLinkPackages))
  , make_ord_flag defGhcFlag "no-hs-main"
        (NoArg (setGeneralFlag Opt_NoHsMain))
  , make_ord_flag defGhcFlag "fno-state-hack"
        (NoArg (setGeneralFlag Opt_G_NoStateHack))
  , make_ord_flag defGhcFlag "fno-opt-coercion"
        (NoArg (setGeneralFlag Opt_G_NoOptCoercion))
  , make_ord_flag defGhcFlag "with-rtsopts"
        (HasArg setRtsOpts)
  , make_ord_flag defGhcFlag "rtsopts"
        (NoArg (setRtsOptsEnabled RtsOptsAll))
  , make_ord_flag defGhcFlag "rtsopts=all"
        (NoArg (setRtsOptsEnabled RtsOptsAll))
  , make_ord_flag defGhcFlag "rtsopts=some"
        (NoArg (setRtsOptsEnabled RtsOptsSafeOnly))
  , make_ord_flag defGhcFlag "rtsopts=none"
        (NoArg (setRtsOptsEnabled RtsOptsNone))
  , make_ord_flag defGhcFlag "rtsopts=ignore"
        (NoArg (setRtsOptsEnabled RtsOptsIgnore))
  , make_ord_flag defGhcFlag "rtsopts=ignoreAll"
        (NoArg (setRtsOptsEnabled RtsOptsIgnoreAll))
  , make_ord_flag defGhcFlag "no-rtsopts"
        (NoArg (setRtsOptsEnabled RtsOptsNone))
  , make_ord_flag defGhcFlag "no-rtsopts-suggestions"
      (noArg (\d -> d {rtsOptsSuggestions = False}))
  , make_ord_flag defGhcFlag "dhex-word-literals"
        (NoArg (setGeneralFlag Opt_HexWordLiterals))

  , make_ord_flag defGhcFlag "ghcversion-file"      (hasArg addGhcVersionFile)
  , make_ord_flag defGhcFlag "main-is"              (SepArg setMainIs)
  , make_ord_flag defGhcFlag "haddock"              (NoArg (setGeneralFlag Opt_Haddock))
  , make_ord_flag defGhcFlag "haddock-opts"         (hasArg addHaddockOpts)
  , make_ord_flag defGhcFlag "hpcdir"               (SepArg setOptHpcDir)
  , make_ord_flag defGhciFlag "ghci-script"         (hasArg addGhciScript)
  , make_ord_flag defGhciFlag "interactive-print"   (hasArg setInteractivePrint)
  , make_ord_flag defGhcFlag "ticky-allocd"
        (NoArg (setGeneralFlag Opt_Ticky_Allocd))
  , make_ord_flag defGhcFlag "ticky-LNE"
        (NoArg (setGeneralFlag Opt_Ticky_LNE))
  , make_ord_flag defGhcFlag "ticky-dyn-thunk"
        (NoArg (setGeneralFlag Opt_Ticky_Dyn_Thunk))
        ------- recompilation checker --------------------------------------
  , make_dep_flag defGhcFlag "recomp"
        (NoArg $ unSetGeneralFlag Opt_ForceRecomp)
             "Use -fno-force-recomp instead"
  , make_dep_flag defGhcFlag "no-recomp"
        (NoArg $ setGeneralFlag Opt_ForceRecomp) "Use -fforce-recomp instead"
  , make_ord_flag defFlag "fmax-errors"
      (intSuffix (\n d -> d { maxErrors = Just (max 1 n) }))
  , make_ord_flag defFlag "fno-max-errors"
      (noArg (\d -> d { maxErrors = Nothing }))
  , make_ord_flag defFlag "freverse-errors"
        (noArg (\d -> d {reverseErrors = True} ))
  , make_ord_flag defFlag "fno-reverse-errors"
        (noArg (\d -> d {reverseErrors = False} ))

        ------ HsCpp opts ---------------------------------------------------
  , make_ord_flag defFlag "D"              (AnySuffix (upd . addOptP))
  , make_ord_flag defFlag "U"              (AnySuffix (upd . addOptP))

        ------- Include/Import Paths ----------------------------------------
  , make_ord_flag defFlag "I"              (Prefix    addIncludePath)
  , make_ord_flag defFlag "i"              (OptPrefix addImportPath)

        ------ Output style options -----------------------------------------
  , make_ord_flag defFlag "dppr-user-length" (intSuffix (\n d ->
                                                       d { pprUserLength = n }))
  , make_ord_flag defFlag "dppr-cols"        (intSuffix (\n d ->
                                                             d { pprCols = n }))
  , make_ord_flag defFlag "fdiagnostics-color=auto"
      (NoArg (upd (\d -> d { useColor = Auto })))
  , make_ord_flag defFlag "fdiagnostics-color=always"
      (NoArg (upd (\d -> d { useColor = Always })))
  , make_ord_flag defFlag "fdiagnostics-color=never"
      (NoArg (upd (\d -> d { useColor = Never })))

  -- Suppress all that is suppressable in core dumps.
  -- Except for uniques, as some simplifier phases introduce new variables that
  -- have otherwise identical names.
  , make_ord_flag defGhcFlag "dsuppress-all"
      (NoArg $ do setGeneralFlag Opt_SuppressCoercions
                  setGeneralFlag Opt_SuppressVarKinds
                  setGeneralFlag Opt_SuppressModulePrefixes
                  setGeneralFlag Opt_SuppressTypeApplications
                  setGeneralFlag Opt_SuppressIdInfo
                  setGeneralFlag Opt_SuppressTicks
                  setGeneralFlag Opt_SuppressStgExts
                  setGeneralFlag Opt_SuppressTypeSignatures
                  setGeneralFlag Opt_SuppressTimestamps)

        ------ Debugging ----------------------------------------------------
  , make_ord_flag defGhcFlag "dstg-stats"
        (NoArg (setGeneralFlag Opt_StgStats))

  , make_ord_flag defGhcFlag "ddump-cmm"
        (setDumpFlag Opt_D_dump_cmm)
  , make_ord_flag defGhcFlag "ddump-cmm-from-stg"
        (setDumpFlag Opt_D_dump_cmm_from_stg)
  , make_ord_flag defGhcFlag "ddump-cmm-raw"
        (setDumpFlag Opt_D_dump_cmm_raw)
  , make_ord_flag defGhcFlag "ddump-cmm-verbose"
        (setDumpFlag Opt_D_dump_cmm_verbose)
  , make_ord_flag defGhcFlag "ddump-cmm-cfg"
        (setDumpFlag Opt_D_dump_cmm_cfg)
  , make_ord_flag defGhcFlag "ddump-cmm-cbe"
        (setDumpFlag Opt_D_dump_cmm_cbe)
  , make_ord_flag defGhcFlag "ddump-cmm-switch"
        (setDumpFlag Opt_D_dump_cmm_switch)
  , make_ord_flag defGhcFlag "ddump-cmm-proc"
        (setDumpFlag Opt_D_dump_cmm_proc)
  , make_ord_flag defGhcFlag "ddump-cmm-sp"
        (setDumpFlag Opt_D_dump_cmm_sp)
  , make_ord_flag defGhcFlag "ddump-cmm-sink"
        (setDumpFlag Opt_D_dump_cmm_sink)
  , make_ord_flag defGhcFlag "ddump-cmm-caf"
        (setDumpFlag Opt_D_dump_cmm_caf)
  , make_ord_flag defGhcFlag "ddump-cmm-procmap"
        (setDumpFlag Opt_D_dump_cmm_procmap)
  , make_ord_flag defGhcFlag "ddump-cmm-split"
        (setDumpFlag Opt_D_dump_cmm_split)
  , make_ord_flag defGhcFlag "ddump-cmm-info"
        (setDumpFlag Opt_D_dump_cmm_info)
  , make_ord_flag defGhcFlag "ddump-cmm-cps"
        (setDumpFlag Opt_D_dump_cmm_cps)
  , make_ord_flag defGhcFlag "ddump-cfg-weights"
        (setDumpFlag