DynFlags.hs 93.4 KB
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-- |
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-- Dynamic flags
--
--
-- (c) The University of Glasgow 2005
--

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-- Most flags are dynamic flags, which means they can change from
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-- 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.
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module DynFlags (
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        -- * Dynamic flags and associated configuration types
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        DynFlag(..),
        DynFlags(..),
        HscTarget(..), isObjectTarget, defaultObjectTarget,
        GhcMode(..), isOneShot,
        GhcLink(..), isNoLink,
        PackageFlag(..),
        Option(..),
        DynLibLoader(..),
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        fFlags, xFlags,
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        dphPackage,
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        -- ** Manipulating DynFlags
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        defaultDynFlags,                -- DynFlags
        initDynFlags,                   -- DynFlags -> IO DynFlags

        dopt,                           -- DynFlag -> DynFlags -> Bool
        dopt_set, dopt_unset,           -- DynFlags -> DynFlag -> DynFlags
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        getOpts,                        -- DynFlags -> (DynFlags -> [a]) -> [a]
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        getVerbFlag,
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        getMainFun,
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        updOptLevel,
        setTmpDir,
        setPackageName,
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        doingTickyProfiling,
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        -- ** Parsing DynFlags
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        parseDynamicFlags,
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        parseDynamicNoPackageFlags,
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        allFlags,
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        supportedLanguages, languageOptions,

        -- ** DynFlag C compiler options
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        machdepCCOpts, picCCOpts,
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        -- * Configuration of the core-to-core passes
        CoreToDo(..),
        SimplifierMode(..),
        SimplifierSwitch(..),
        FloatOutSwitches(..),
        getCoreToDo,

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

        -- * Compiler configuration suitable for display to the user
        compilerInfo
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  ) where

#include "HsVersions.h"

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#ifndef OMIT_NATIVE_CODEGEN
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import Platform
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#endif
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import Module
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import PackageConfig
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import PrelNames        ( mAIN, main_RDR_Unqual )
import RdrName          ( RdrName, mkRdrUnqual )
import OccName          ( mkVarOccFS )
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#if defined(i386_TARGET_ARCH) || (!defined(mingw32_TARGET_OS) && !defined(darwin_TARGET_OS))
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import StaticFlags      ( opt_Static )
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#endif
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import StaticFlags      ( opt_PIC, WayName(..), v_Ways, v_Build_tag,
                          v_RTS_Build_tag )
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import {-# SOURCE #-} Packages (PackageState)
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import DriverPhases     ( Phase(..), phaseInputExt )
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import Config
import CmdLineParser
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import Constants        ( mAX_CONTEXT_REDUCTION_DEPTH )
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import Panic
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import UniqFM           ( UniqFM )
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import Util
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import Maybes           ( orElse )
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import SrcLoc
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import FastString
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import FiniteMap
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import Outputable
import {-# SOURCE #-} ErrUtils ( Severity(..), Message, mkLocMessage )
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import Data.IORef
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import Control.Monad    ( when )
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import Data.Char
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import Data.List        ( intersperse )
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import System.FilePath
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import System.IO        ( stderr, hPutChar )
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-- -----------------------------------------------------------------------------
-- DynFlags

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

   -- debugging flags
   = Opt_D_dump_cmm
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   | Opt_D_dump_cmmz
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   | Opt_D_dump_cmmz_pretty
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   | Opt_D_dump_cps_cmm
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   | Opt_D_dump_cvt_cmm
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   | Opt_D_dump_asm
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   | Opt_D_dump_asm_native
   | Opt_D_dump_asm_liveness
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   | Opt_D_dump_asm_coalesce
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   | Opt_D_dump_asm_regalloc
   | Opt_D_dump_asm_regalloc_stages
   | Opt_D_dump_asm_conflicts
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   | Opt_D_dump_asm_stats
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   | Opt_D_dump_asm_expanded
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   | Opt_D_dump_cpranal
   | Opt_D_dump_deriv
   | Opt_D_dump_ds
   | Opt_D_dump_flatC
   | Opt_D_dump_foreign
   | Opt_D_dump_inlinings
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   | Opt_D_dump_rule_firings
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   | Opt_D_dump_occur_anal
   | Opt_D_dump_parsed
   | Opt_D_dump_rn
   | Opt_D_dump_simpl
   | Opt_D_dump_simpl_iterations
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   | Opt_D_dump_simpl_phases
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   | Opt_D_dump_spec
   | Opt_D_dump_prep
   | Opt_D_dump_stg
   | Opt_D_dump_stranal
   | Opt_D_dump_tc
   | Opt_D_dump_types
   | Opt_D_dump_rules
   | Opt_D_dump_cse
   | Opt_D_dump_worker_wrapper
   | Opt_D_dump_rn_trace
   | Opt_D_dump_rn_stats
   | Opt_D_dump_opt_cmm
   | Opt_D_dump_simpl_stats
   | Opt_D_dump_tc_trace
   | Opt_D_dump_if_trace
   | Opt_D_dump_splices
   | Opt_D_dump_BCOs
   | Opt_D_dump_vect
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   | Opt_D_dump_hpc
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   | Opt_D_dump_rtti
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   | Opt_D_source_stats
   | Opt_D_verbose_core2core
   | Opt_D_verbose_stg2stg
   | Opt_D_dump_hi
   | Opt_D_dump_hi_diffs
   | Opt_D_dump_minimal_imports
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   | Opt_D_dump_mod_cycles
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   | Opt_D_dump_view_pattern_commoning
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   | Opt_D_faststring_stats
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   | Opt_DumpToFile                     -- ^ Append dump output to files instead of stdout.
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   | Opt_D_no_debug_output
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   | Opt_DoCoreLinting
   | Opt_DoStgLinting
   | Opt_DoCmmLinting
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   | Opt_DoAsmLinting
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   | Opt_WarnIsError                    -- -Werror; makes warnings fatal
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   | Opt_WarnDuplicateExports
   | Opt_WarnHiShadows
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   | Opt_WarnImplicitPrelude
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   | Opt_WarnIncompletePatterns
   | Opt_WarnIncompletePatternsRecUpd
   | Opt_WarnMissingFields
   | Opt_WarnMissingMethods
   | Opt_WarnMissingSigs
   | Opt_WarnNameShadowing
   | Opt_WarnOverlappingPatterns
   | Opt_WarnSimplePatterns
   | Opt_WarnTypeDefaults
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   | Opt_WarnMonomorphism
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   | Opt_WarnUnusedBinds
   | Opt_WarnUnusedImports
   | Opt_WarnUnusedMatches
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   | Opt_WarnWarningsDeprecations
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   | Opt_WarnDeprecatedFlags
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   | Opt_WarnDodgyImports
   | Opt_WarnOrphans
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   | Opt_WarnTabs
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   | Opt_WarnUnrecognisedPragmas
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   | Opt_WarnDodgyForeignImports
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   -- language opts
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   | Opt_OverlappingInstances
   | Opt_UndecidableInstances
   | Opt_IncoherentInstances
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   | Opt_MonomorphismRestriction
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   | Opt_MonoPatBinds
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   | Opt_ExtendedDefaultRules           -- Use GHC's extended rules for defaulting
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   | Opt_ForeignFunctionInterface
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   | Opt_UnliftedFFITypes
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   | Opt_PArr                           -- Syntactic support for parallel arrays
   | Opt_Arrows                         -- Arrow-notation syntax
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   | Opt_TemplateHaskell
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   | Opt_QuasiQuotes
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   | Opt_ImplicitParams
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   | Opt_Generics			-- "Derivable type classes"
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   | Opt_ImplicitPrelude
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   | Opt_ScopedTypeVariables
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   | Opt_UnboxedTuples
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   | Opt_BangPatterns
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   | Opt_TypeFamilies
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   | Opt_OverloadedStrings
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   | Opt_DisambiguateRecordFields
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   | Opt_RecordWildCards
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   | Opt_RecordPuns
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   | Opt_ViewPatterns
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   | Opt_GADTs
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   | Opt_RelaxedPolyRec
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   | Opt_StandaloneDeriving
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   | Opt_DeriveDataTypeable
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   | Opt_DeriveFunctor
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   | Opt_DeriveTraversable
   | Opt_DeriveFoldable

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   | Opt_TypeSynonymInstances
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   | Opt_FlexibleContexts
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   | Opt_FlexibleInstances
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   | Opt_ConstrainedClassMethods
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   | Opt_MultiParamTypeClasses
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   | Opt_FunctionalDependencies
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   | Opt_UnicodeSyntax
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   | Opt_PolymorphicComponents
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   | Opt_ExistentialQuantification
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   | Opt_MagicHash
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   | Opt_EmptyDataDecls
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   | Opt_KindSignatures
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   | Opt_ParallelListComp
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   | Opt_TransformListComp
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   | Opt_GeneralizedNewtypeDeriving
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   | Opt_RecursiveDo
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   | Opt_PostfixOperators
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   | Opt_PatternGuards
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   | Opt_LiberalTypeSynonyms
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   | Opt_Rank2Types
   | Opt_RankNTypes
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   | Opt_ImpredicativeTypes
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   | Opt_TypeOperators
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   | Opt_PackageImports
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   | Opt_NewQualifiedOperators
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   | Opt_PrintExplicitForalls

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   -- optimisation opts
   | Opt_Strictness
   | Opt_FullLaziness
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   | Opt_StaticArgumentTransformation
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   | Opt_CSE
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   | Opt_LiberateCase
   | Opt_SpecConstr
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   | Opt_IgnoreInterfacePragmas
   | Opt_OmitInterfacePragmas
   | Opt_DoLambdaEtaExpansion
   | Opt_IgnoreAsserts
   | Opt_DoEtaReduction
   | Opt_CaseMerge
   | Opt_UnboxStrictFields
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   | Opt_MethodSharing
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   | Opt_DictsCheap
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   | Opt_InlineIfEnoughArgs
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   | Opt_EnableRewriteRules		-- Apply rewrite rules during simplification
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   | Opt_Vectorise
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   | Opt_RegsGraph                      -- do graph coloring register allocation
   | Opt_RegsIterative                  -- do iterative coalescing graph coloring register allocation
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   -- profiling opts
   | Opt_AutoSccsOnAllToplevs
   | Opt_AutoSccsOnExportedToplevs
   | Opt_AutoSccsOnIndividualCafs

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   -- misc opts
   | Opt_Cpp
   | Opt_Pp
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   | Opt_ForceRecomp
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   | Opt_DryRun
   | Opt_DoAsmMangling
   | Opt_ExcessPrecision
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   | Opt_EagerBlackHoling
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   | Opt_ReadUserPackageConf
   | Opt_NoHsMain
   | Opt_SplitObjs
   | Opt_StgStats
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   | Opt_HideAllPackages
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   | Opt_PrintBindResult
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   | Opt_Haddock
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   | Opt_HaddockOptions
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   | Opt_Hpc_No_Auto
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   | Opt_BreakOnException
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   | Opt_BreakOnError
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   | Opt_PrintEvldWithShow
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   | Opt_PrintBindContents
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   | Opt_GenManifest
   | Opt_EmbedManifest
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	-- temporary flags
   | Opt_RunCPS
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   | Opt_RunCPSZ
   | Opt_ConvertToZipCfgAndBack
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   | Opt_AutoLinkPackages
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   | Opt_ImplicitImportQualified
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   | Opt_TryNewCodeGen
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   -- keeping stuff
   | Opt_KeepHiDiffs
   | Opt_KeepHcFiles
   | Opt_KeepSFiles
   | Opt_KeepRawSFiles
   | Opt_KeepTmpFiles
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   | Opt_KeepRawTokenStream
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   deriving (Eq, Show)
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-- | Contains not only a collection of 'DynFlag's but also a plethora of
-- information relating to the compilation of a single file or GHC session
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data DynFlags = DynFlags {
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  ghcMode               :: GhcMode,
  ghcLink               :: GhcLink,
  coreToDo              :: Maybe [CoreToDo], -- reserved for -Ofile
  stgToDo               :: Maybe [StgToDo],  -- similarly
  hscTarget             :: HscTarget,
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  hscOutName            :: String,      -- ^ Name of the output file
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  extCoreName           :: String,      -- ^ Name of the .hcr output file
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  verbosity             :: Int,         -- ^ Verbosity level: see "DynFlags#verbosity_levels"
  optLevel              :: Int,         -- ^ Optimisation level
  simplPhases           :: Int,         -- ^ Number of simplifier phases
  maxSimplIterations    :: Int,         -- ^ Max simplifier iterations
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  shouldDumpSimplPhase  :: SimplifierMode -> Bool,
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  ruleCheck             :: Maybe String,
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  specConstrThreshold   :: Maybe Int,   -- ^ Threshold for SpecConstr
  specConstrCount       :: Maybe Int,   -- ^ Max number of specialisations for any one function
  liberateCaseThreshold :: Maybe Int,   -- ^ Threshold for LiberateCase
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#ifndef OMIT_NATIVE_CODEGEN
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  targetPlatform	:: Platform,	-- ^ The platform we're compiling for. Used by the NCG.
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#endif
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  stolen_x86_regs       :: Int,
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  cmdlineHcIncludes     :: [String],    -- ^ @\-\#includes@
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  importPaths           :: [FilePath],
  mainModIs             :: Module,
  mainFunIs             :: Maybe String,
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  ctxtStkDepth          :: Int,         -- ^ Typechecker context stack depth
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  dphBackend            :: DPHBackend,

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  thisPackage           :: PackageId,   -- ^ name of package currently being compiled
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  -- ways
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  wayNames              :: [WayName],   -- ^ Way flags from the command line
  buildTag              :: String,      -- ^ The global \"way\" (e.g. \"p\" for prof)
  rtsBuildTag           :: String,      -- ^ The RTS \"way\"
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  -- For object splitting
  splitInfo             :: Maybe (String,Int),

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  -- paths etc.
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  objectDir             :: Maybe String,
  hiDir                 :: Maybe String,
  stubDir               :: Maybe String,
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  objectSuf             :: String,
  hcSuf                 :: String,
  hiSuf                 :: String,
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  outputFile            :: Maybe String,
  outputHi              :: Maybe String,
  dynLibLoader          :: DynLibLoader,
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  -- | This is set by 'DriverPipeline.runPipeline' based on where
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  --    its output is going.
  dumpPrefix            :: Maybe FilePath,
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  -- | Override the 'dumpPrefix' set by 'DriverPipeline.runPipeline'.
  --    Set by @-ddump-file-prefix@
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  dumpPrefixForce       :: Maybe FilePath,

  includePaths          :: [String],
  libraryPaths          :: [String],
  frameworkPaths        :: [String],    -- used on darwin only
  cmdlineFrameworks     :: [String],    -- ditto
  tmpDir                :: String,      -- no trailing '/'

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  ghcUsagePath          :: FilePath,    -- Filled in by SysTools
  ghciUsagePath         :: FilePath,    -- ditto

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  hpcDir                :: String,      -- ^ Path to store the .mix files
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  -- options for particular phases
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  opt_L                 :: [String],
  opt_P                 :: [String],
  opt_F                 :: [String],
  opt_c                 :: [String],
  opt_m                 :: [String],
  opt_a                 :: [String],
  opt_l                 :: [String],
  opt_windres           :: [String],
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  -- commands for particular phases
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  pgm_L                 :: String,
  pgm_P                 :: (String,[Option]),
  pgm_F                 :: String,
  pgm_c                 :: (String,[Option]),
  pgm_m                 :: (String,[Option]),
  pgm_s                 :: (String,[Option]),
  pgm_a                 :: (String,[Option]),
  pgm_l                 :: (String,[Option]),
  pgm_dll               :: (String,[Option]),
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  pgm_T                 :: String,
  pgm_sysman            :: String,
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  pgm_windres           :: String,
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  --  For ghc -M
  depMakefile           :: FilePath,
  depIncludePkgDeps     :: Bool,
  depExcludeMods        :: [ModuleName],
  depSuffixes           :: [String],

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  --  Package flags
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  extraPkgConfs         :: [FilePath],
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  topDir                :: FilePath,    -- filled in by SysTools
  systemPackageConfig   :: FilePath,    -- ditto
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        -- ^ The @-package-conf@ flags given on the command line, in the order
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        -- they appeared.
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  packageFlags          :: [PackageFlag],
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        -- ^ The @-package@ and @-hide-package@ flags from the command-line
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  -- Package state
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  -- NB. do not modify this field, it is calculated by
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  -- Packages.initPackages and Packages.updatePackages.
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  pkgDatabase           :: Maybe (UniqFM PackageConfig),
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  pkgState              :: PackageState,
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  -- Temporary files
  -- These have to be IORefs, because the defaultCleanupHandler needs to
  -- know what to clean when an exception happens
  filesToClean          :: IORef [FilePath],
  dirsToClean           :: IORef (FiniteMap FilePath FilePath),

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  -- hsc dynamic flags
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  flags                 :: [DynFlag],

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  -- | Message output action: use "ErrUtils" instead of this if you can
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  log_action            :: Severity -> SrcSpan -> PprStyle -> Message -> IO (),

  haddockOptions :: Maybe String
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 }

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

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-- | Will this target result in an object file on the disk?
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isObjectTarget :: HscTarget -> Bool
isObjectTarget HscC     = True
isObjectTarget HscAsm   = True
isObjectTarget _        = 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.
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data GhcMode
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  = CompManager         -- ^ @\-\-make@, GHCi, etc.
  | OneShot             -- ^ @ghc -c Foo.hs@
  | MkDepend            -- ^ @ghc -M@, see "Finder" for why we need this
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  deriving Eq

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

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

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-- | 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
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  | LinkInMemory        -- ^ Use the in-memory dynamic linker (works for both
                        --   bytecode and object code).
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  | LinkDynLib          -- ^ Link objects into a dynamic lib (DLL on Windows, DSO on ELF platforms)
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  deriving (Eq, Show)
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isNoLink :: GhcLink -> Bool
isNoLink NoLink = True
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isNoLink _      = False
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-- Is it worth evaluating this Bool and caching it in the DynFlags value
-- during initDynFlags?
doingTickyProfiling :: DynFlags -> Bool
doingTickyProfiling dflags = WayTicky `elem` wayNames dflags

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data PackageFlag
  = ExposePackage  String
  | HidePackage    String
  | IgnorePackage  String
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  deriving Eq
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defaultHscTarget :: HscTarget
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defaultHscTarget = defaultObjectTarget

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-- | The 'HscTarget' value corresponding to the default way to create
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-- object files on the current platform.
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defaultObjectTarget :: HscTarget
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defaultObjectTarget
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  | cGhcWithNativeCodeGen == "YES"      =  HscAsm
  | otherwise                           =  HscC
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data DynLibLoader
  = Deployable
  | Wrapped (Maybe String)
  | SystemDependent
  deriving Eq

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-- | Used by 'GHC.newSession' to partially initialize a new 'DynFlags' value
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initDynFlags :: DynFlags -> IO DynFlags
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initDynFlags dflags = do
 -- someday these will be dynamic flags
 ways <- readIORef v_Ways
 build_tag <- readIORef v_Build_tag
 rts_build_tag <- readIORef v_RTS_Build_tag
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 refFilesToClean <- newIORef []
 refDirsToClean <- newIORef emptyFM
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 return dflags{
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        wayNames        = ways,
        buildTag        = build_tag,
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        rtsBuildTag     = rts_build_tag,
        filesToClean    = refFilesToClean,
        dirsToClean     = refDirsToClean
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        }
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-- | The normal 'DynFlags'. Note that they is not suitable for use in this form
-- and must be fully initialized by 'GHC.newSession' first.
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defaultDynFlags :: DynFlags
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defaultDynFlags =
     DynFlags {
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        ghcMode                 = CompManager,
        ghcLink                 = LinkBinary,
        coreToDo                = Nothing,
        stgToDo                 = Nothing,
        hscTarget               = defaultHscTarget,
        hscOutName              = "",
        extCoreName             = "",
        verbosity               = 0,
        optLevel                = 0,
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        simplPhases             = 2,
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        maxSimplIterations      = 4,
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        shouldDumpSimplPhase    = const False,
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        ruleCheck               = Nothing,
        specConstrThreshold     = Just 200,
        specConstrCount         = Just 3,
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        liberateCaseThreshold   = Just 200,
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#ifndef OMIT_NATIVE_CODEGEN
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        targetPlatform          = defaultTargetPlatform,
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#endif
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        stolen_x86_regs         = 4,
        cmdlineHcIncludes       = [],
        importPaths             = ["."],
        mainModIs               = mAIN,
        mainFunIs               = Nothing,
        ctxtStkDepth            = mAX_CONTEXT_REDUCTION_DEPTH,

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        dphBackend              = DPHPar,

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        thisPackage             = mainPackageId,

        objectDir               = Nothing,
        hiDir                   = Nothing,
        stubDir                 = Nothing,

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

        outputFile              = Nothing,
        outputHi                = Nothing,
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        dynLibLoader            = SystemDependent,
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        dumpPrefix              = Nothing,
        dumpPrefixForce         = Nothing,
        includePaths            = [],
        libraryPaths            = [],
        frameworkPaths          = [],
        cmdlineFrameworks       = [],
        tmpDir                  = cDEFAULT_TMPDIR,

        hpcDir                  = ".hpc",

        opt_L                   = [],
        opt_P                   = (if opt_PIC
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                                   then ["-D__PIC__", "-U __PIC__"] -- this list is reversed
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                                   else []),
        opt_F                   = [],
        opt_c                   = [],
        opt_a                   = [],
        opt_m                   = [],
        opt_l                   = [],
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        opt_windres             = [],
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        extraPkgConfs           = [],
        packageFlags            = [],
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        pkgDatabase             = Nothing,
        pkgState                = panic "no package state yet: call GHC.setSessionDynFlags",
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        wayNames                = panic "defaultDynFlags: No wayNames",
        buildTag                = panic "defaultDynFlags: No buildTag",
        rtsBuildTag             = panic "defaultDynFlags: No rtsBuildTag",
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        splitInfo               = Nothing,
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        -- initSysTools fills all these in
        ghcUsagePath            = panic "defaultDynFlags: No ghciUsagePath",
        ghciUsagePath           = panic "defaultDynFlags: No ghciUsagePath",
        topDir                  = panic "defaultDynFlags: No topDir",
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        systemPackageConfig     = panic  "no systemPackageConfig: call GHC.setSessionDynFlags",
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        pgm_L                   = panic "defaultDynFlags: No pgm_L",
        pgm_P                   = panic "defaultDynFlags: No pgm_P",
        pgm_F                   = panic "defaultDynFlags: No pgm_F",
        pgm_c                   = panic "defaultDynFlags: No pgm_c",
        pgm_m                   = panic "defaultDynFlags: No pgm_m",
        pgm_s                   = panic "defaultDynFlags: No pgm_s",
        pgm_a                   = panic "defaultDynFlags: No pgm_a",
        pgm_l                   = panic "defaultDynFlags: No pgm_l",
        pgm_dll                 = panic "defaultDynFlags: No pgm_dll",
        pgm_T                   = panic "defaultDynFlags: No pgm_T",
        pgm_sysman              = panic "defaultDynFlags: No pgm_sysman",
        pgm_windres             = panic "defaultDynFlags: No pgm_windres",
        -- end of initSysTools values
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        -- ghc -M values
        depMakefile       = "Makefile",
        depIncludePkgDeps = False,
        depExcludeMods    = [],
        depSuffixes       = [],
        -- end of ghc -M values
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        filesToClean   = panic "defaultDynFlags: No filesToClean",
        dirsToClean    = panic "defaultDynFlags: No dirsToClean",
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        haddockOptions = Nothing,
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        flags = [
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            Opt_AutoLinkPackages,
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            Opt_ReadUserPackageConf,

            Opt_MonoPatBinds,   -- Experimentally, I'm making this non-standard
                                -- behaviour the default, to see if anyone notices
                                -- SLPJ July 06

            Opt_ImplicitPrelude,
            Opt_MonomorphismRestriction,

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            Opt_MethodSharing,

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            Opt_DoAsmMangling,

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            Opt_GenManifest,
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            Opt_EmbedManifest,
            Opt_PrintBindContents
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            ]
            ++ [f | (ns,f) <- optLevelFlags, 0 `elem` ns]
                    -- The default -O0 options
            ++ standardWarnings,

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        log_action = \severity srcSpan style msg ->
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                        case severity of
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                          SevInfo  -> printErrs (msg style)
                          SevFatal -> printErrs (msg style)
                          _        -> do 
                                hPutChar stderr '\n'
                                printErrs ((mkLocMessage srcSpan msg) 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.
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      }

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{-
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    #verbosity_levels#
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    Verbosity levels:
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    0   |   print errors & warnings only
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    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"
-}

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-- | Test whether a 'DynFlag' is set
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dopt :: DynFlag -> DynFlags -> Bool
dopt f dflags  = f `elem` (flags dflags)

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-- | Set a 'DynFlag'
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dopt_set :: DynFlags -> DynFlag -> DynFlags
dopt_set dfs f = dfs{ flags = f : flags dfs }

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-- | Unset a 'DynFlag'
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dopt_unset :: DynFlags -> DynFlag -> DynFlags
dopt_unset dfs f = dfs{ flags = filter (/= f) (flags dfs) }

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-- | 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
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getOpts dflags opts = reverse (opts dflags)
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        -- We add to the options from the front, so we need to reverse the list
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-- | 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
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getVerbFlag :: DynFlags -> String
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getVerbFlag dflags
  | verbosity dflags >= 3  = "-v"
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  | otherwise =  ""

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setObjectDir, setHiDir, setStubDir, setOutputDir,
         setObjectSuf, setHiSuf, setHcSuf, parseDynLibLoaderMode,
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         setPgmP, setPgmL, setPgmF, setPgmc, setPgmm, setPgms, setPgma, setPgml, setPgmdll, setPgmwindres,
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         addOptL, addOptP, addOptF, addOptc, addOptm, addOpta, addOptl, addOptwindres,
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         addCmdlineFramework, addHaddockOpts
   :: String -> DynFlags -> DynFlags
setOutputFile, setOutputHi, setDumpPrefixForce
   :: Maybe String -> DynFlags -> DynFlags

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setObjectDir  f d = d{ objectDir  = Just f}
setHiDir      f d = d{ hiDir      = Just f}
setStubDir    f d = d{ stubDir    = Just f, includePaths = f : includePaths d }
  -- -stubdir D adds an implicit -I D, so that gcc can find the _stub.h file
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  -- \#included from the .hc file when compiling with -fvia-C.
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setOutputDir  f = setObjectDir f . setHiDir f . setStubDir f
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setObjectSuf  f d = d{ objectSuf  = f}
setHiSuf      f d = d{ hiSuf      = f}
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setHcSuf      f d = d{ hcSuf      = f}

setOutputFile f d = d{ outputFile = f}
setOutputHi   f d = d{ outputHi   = f}
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parseDynLibLoaderMode f d =
 case splitAt 8 f of
   ("deploy", "")       -> d{ dynLibLoader = Deployable }
   ("sysdep", "")       -> d{ dynLibLoader = SystemDependent }
   ("wrapped", "")      -> d{ dynLibLoader = Wrapped Nothing }
   ("wrapped:", "hard") -> d{ dynLibLoader = Wrapped Nothing }
   ("wrapped:", flex)   -> d{ dynLibLoader = Wrapped (Just flex) }
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   _                    -> ghcError (CmdLineError ("Unknown dynlib loader: " ++ f))
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setDumpPrefixForce f d = d { dumpPrefixForce = f}

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-- XXX HACK: Prelude> words "'does not' work" ===> ["'does","not'","work"]
-- Config.hs should really use Option.
setPgmP   f d = let (pgm:args) = words f in d{ pgm_P   = (pgm, map Option args)}

setPgmL   f d = d{ pgm_L   = f}
setPgmF   f d = d{ pgm_F   = f}
setPgmc   f d = d{ pgm_c   = (f,[])}
setPgmm   f d = d{ pgm_m   = (f,[])}
setPgms   f d = d{ pgm_s   = (f,[])}
setPgma   f d = d{ pgm_a   = (f,[])}
setPgml   f d = d{ pgm_l   = (f,[])}
setPgmdll f d = d{ pgm_dll = (f,[])}
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setPgmwindres f d = d{ pgm_windres = f}
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addOptL   f d = d{ opt_L   = f : opt_L d}
addOptP   f d = d{ opt_P   = f : opt_P d}
addOptF   f d = d{ opt_F   = f : opt_F d}
addOptc   f d = d{ opt_c   = f : opt_c d}
addOptm   f d = d{ opt_m   = f : opt_m d}
addOpta   f d = d{ opt_a   = f : opt_a d}
addOptl   f d = d{ opt_l   = f : opt_l d}
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addOptwindres f d = d{ opt_windres = f : opt_windres d}
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setDepMakefile :: FilePath -> DynFlags -> DynFlags
setDepMakefile f d = d { depMakefile = deOptDep f }

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

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

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

-- XXX Legacy code:
-- We used to use "-optdep-flag -optdeparg", so for legacy applications
-- we need to strip the "-optdep" off of the arg
deOptDep :: String -> String
deOptDep x = case maybePrefixMatch "-optdep" x of
             Just rest -> rest
             Nothing -> x

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

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addHaddockOpts f d = d{ haddockOptions = Just f}

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

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-- | When invoking external tools as part of the compilation pipeline, we
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-- 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
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-- between filepaths and 'other stuff'. The reason for this is that
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-- to whatever format they're expected to be on a particular platform.
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data Option
 = FileOption -- an entry that _contains_ filename(s) / filepaths.
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              String  -- a non-filepath prefix that shouldn't be
                      -- transformed (e.g., "/out=")
              String  -- the filepath/filename portion
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 | Option     String
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-----------------------------------------------------------------------------
-- Setting the optimisation level

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

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   extra_dopts  = [ f | (ns,f) <- optLevelFlags, final_n `elem` ns ]
   remove_dopts = [ f | (ns,f) <- optLevelFlags, final_n `notElem` ns ]
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optLevelFlags :: [([Int], DynFlag)]
optLevelFlags
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  = [ ([0],     Opt_IgnoreInterfacePragmas)
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    , ([0],     Opt_OmitInterfacePragmas)
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    , ([1,2],   Opt_IgnoreAsserts)
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    , ([1,2],   Opt_EnableRewriteRules)  -- Off for -O0; see Note [Scoping for Builtin rules]
                                         --              in PrelRules
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    , ([1,2],   Opt_DoEtaReduction)
    , ([1,2],   Opt_CaseMerge)
    , ([1,2],   Opt_Strictness)
    , ([1,2],   Opt_CSE)
    , ([1,2],   Opt_FullLaziness)
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    , ([2],     Opt_LiberateCase)
    , ([2],     Opt_SpecConstr)
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--     , ([2],     Opt_StaticArgumentTransformation)
-- Max writes: I think it's probably best not to enable SAT with -O2 for the
-- 6.10 release. The version of SAT in HEAD at the moment doesn't incorporate
-- several improvements to the heuristics, and I'm concerned that without
-- those changes SAT will interfere with some attempts to write "high
-- performance Haskell", as we saw in some posts on Haskell-Cafe earlier
-- this year. In particular, the version in HEAD lacks the tail call
-- criterion, so many things that look like reasonable loops will be
-- turned into functions with extra (unneccesary) thunk creation.
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    , ([0,1,2], Opt_DoLambdaEtaExpansion)
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                -- This one is important for a tiresome reason:
                -- we want to make sure that the bindings for data
                -- constructors are eta-expanded.  This is probably
                -- a good thing anyway, but it seems fragile.
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    ]

-- -----------------------------------------------------------------------------
-- Standard sets of warning options

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standardWarnings :: [DynFlag]
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standardWarnings
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    = [ Opt_WarnWarningsDeprecations,
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        Opt_WarnDeprecatedFlags,
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        Opt_WarnUnrecognisedPragmas,
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        Opt_WarnOverlappingPatterns,
        Opt_WarnMissingFields,
        Opt_WarnMissingMethods,
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        Opt_WarnDuplicateExports,
        Opt_WarnDodgyForeignImports
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      ]

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minusWOpts :: [DynFlag]
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minusWOpts
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    = standardWarnings ++
      [ Opt_WarnUnusedBinds,
        Opt_WarnUnusedMatches,
        Opt_WarnUnusedImports,
        Opt_WarnIncompletePatterns,
        Opt_WarnDodgyImports
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      ]

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minusWallOpts :: [DynFlag]
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minusWallOpts
    = minusWOpts ++
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      [ Opt_WarnTypeDefaults,
        Opt_WarnNameShadowing,
        Opt_WarnMissingSigs,
        Opt_WarnHiShadows,
        Opt_WarnOrphans
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      ]

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-- minuswRemovesOpts should be every warning option
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minuswRemovesOpts :: [DynFlag]
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minuswRemovesOpts
    = minusWallOpts ++
      [Opt_WarnImplicitPrelude,
       Opt_WarnIncompletePatternsRecUpd,
       Opt_WarnSimplePatterns,
       Opt_WarnMonomorphism,
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       Opt_WarnTabs
      ]

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-- -----------------------------------------------------------------------------
-- CoreToDo:  abstraction of core-to-core passes to run.

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data CoreToDo           -- These are diff core-to-core passes,
                        -- which may be invoked in any order,
                        -- as many times as you like.
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  = CoreDoSimplify      -- The core-to-core simplifier.
        SimplifierMode
        [SimplifierSwitch]
                        -- Each run of the simplifier can take a different
                        -- set of simplifier-specific flags.
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  | CoreDoFloatInwards
  | CoreDoFloatOutwards FloatOutSwitches
  | CoreLiberateCase
  | CoreDoPrintCore
  | CoreDoStaticArgs
  | CoreDoStrictness
  | CoreDoWorkerWrapper
  | CoreDoSpecialising
  | CoreDoSpecConstr
  | CoreDoOldStrictness
  | CoreDoGlomBinds
  | CoreCSE
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  | CoreDoRuleCheck Int{-CompilerPhase-} String -- Check for non-application of rules
                                                -- matching this string
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  | CoreDoVectorisation PackageId
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  | CoreDoNothing                -- Useful when building up
  | CoreDoPasses [CoreToDo]      -- lists of these things
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data SimplifierMode             -- See comments in SimplMonad
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  = SimplGently
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  | SimplPhase Int [String]
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instance Outputable SimplifierMode where
    ppr SimplGently       = ptext (sLit "gentle")
    ppr (SimplPhase n ss) = int n <+> brackets (text (concat $ intersperse "," ss))


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data SimplifierSwitch
  = MaxSimplifierIterations Int
  | NoCaseOfCase

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data FloatOutSwitches = FloatOutSwitches {
        floatOutLambdas :: Bool,     -- ^ True <=> float lambdas to top level
        floatOutConstants :: Bool    -- ^ True <=> float constants to top level,
                                     --            even if they do not escape a lambda
    }

instance Outputable FloatOutSwitches where
    ppr = pprFloatOutSwitches

pprFloatOutSwitches :: FloatOutSwitches -> SDoc
pprFloatOutSwitches sw = pp_not (floatOutLambdas sw) <+> text "lambdas" <> comma
                     <+> pp_not (floatOutConstants sw) <+> text "constants"
  where
    pp_not True  = empty
    pp_not False = text "not"

-- | Switches that specify the minimum amount of floating out
1008