Provided by: ghc_7.6.3-10_amd64 
NAME
GHC - the Glasgow Haskell Compiler
SYNOPSIS
ghc [option|filename]...
ghci [option|filename]...
DESCRIPTION
This manual page documents briefly the ghc and ghci commands. Note that ghci is not yet
available on all architectures. Extensive documentation is available in various other
formats including DVI, PostScript and HTML; see below.
Each of GHC's command line options is classified as either static or dynamic. A static
flag may only be specified on the command line, whereas a dynamic flag may also be given
in an OPTIONS pragma in a source file or set from the GHCi command-line with :set.
As a rule of thumb, all the language options are dynamic, as are the warning options and
the debugging options.
The rest are static, with the notable exceptions of -v, -cpp, -fasm, -fvia-C, -fllvm, and
" -#include . The OPTIONS sections lists the status of each flag.
Common suffixes of file names for Haskell are:
.hs Haskell source code; preprocess, compile
.lhs literate Haskell source; unlit, preprocess, compile
.hi Interface file; contains information about exported symbols
.hc intermediate C files
.x_o way x object files; common ways are: p, u, s
.x_hi way x interface files
OPTIONS
Help and verbosity options
-? -help -v -vn -V --supported-extensions or --supported-languages --info --version
--numeric-version --print-libdir -ferror-spans -Hsize -Rghc-timing
Which phases to run
-E -C -S -c -x suffix
Alternative modes of operation
--interactive --make -e expr -M
Redirecting output
-hcsuf suffix -hidir dir -hisuf suffix -o filename -odir dir -ohi filename -osuf
suffix -stubdir dir -dumpdir dir -outputdir dir
Keeping intermediate files
-keep-hc-file or
-keep-hc-files -keep-llvm-file or
-keep-llvm-files -keep-s-file or
-keep-s-files -keep-tmp-files
Temporary files
-tmpdir
Finding imports
-idir1:dir2:... -i
Interface file options
-ddump-hi -ddump-hi-diffs -ddump-minimal-imports --show-iface file
Recompilation checking
-fforce-recomp -fno-force-recomp
Interactive-mode options
-ignore-dot-ghci -ghci-script -fbreak-on-exception -fno-break-on-exception
-fbreak-on-error -fno-break-on-error -fprint-evld-with-show -fno-print-evld-with-show
-fprint-bind-result -fno-print-bind-result -fno-print-bind-contents
-fno-implicit-import-qualified -interactive-print
Packages
-package-name P -package P -hide-all-packages -hide-package name -ignore-package name
-package-db file -clear-package-db -no-global-package-db -global-package-db
-no-user-package-db -user-package-db -no-auto-link-packages -trust P -distrust P
-distrust-all
Language options
-fglasgow-exts -fno-glasgow-exts -XOverlappingInstances -XNoOverlappingInstances
-XIncoherentInstances -XNoIncoherentInstances -XUndecidableInstances
-XNoUndecidableInstances -fcontext-stack=Nn -XArrows -XNoArrows
-XDisambiguateRecordFields -XNoDisambiguateRecordFields -XForeignFunctionInterface
-XNoForeignFunctionInterface -XGenerics -XNoGenerics -XImplicitParams -XNoImplicitParams
-firrefutable-tuples -fno-irrefutable-tuples -XNoImplicitPrelude -XImplicitPrelude
-XRebindableSyntax -XNoRebindableSyntax -XNoMonomorphismRestriction
-XMonomorphismRrestriction -XNoNPlusKPatterns -XNPlusKPatterns
-XNoTraditionalRecordSyntax -XTraditionalRecordSyntax -XNoMonoPatBinds -XMonoPatBinds
-XRelaxedPolyRec -XNoRelaxedPolyRec -XExtendedDefaultRules -XNoExtendedDefaultRules
-XOverloadedStrings -XNoOverloadedStrings -XGADTs -XNoGADTs -XGADTSyntax -XNoGADTSyntax
-XTypeFamilies -XNoTypeFamilies -XConstraintKinds -XNoConstraintKinds -XDataKinds
-XNoDataKinds -XPolyKinds -XNoPolyKinds -XScopedTypeVariables -XNoScopedTypeVariables
-XMonoLocalBinds -XNoMonoLocalBinds -XTemplateHaskell -XNoTemplateHaskell -XQuasiQuotes
-XNoQuasiQuotes -XBangPatterns -XNoBangPatterns -XCPP -XNoCPP -XPatternGuards
-XNoPatternGuards -XViewPatterns -XNoViewPatterns -XUnicodeSyntax -XNoUnicodeSyntax
-XMagicHash -XNoMagicHash -XExplicitForAll -XNoExplicitForAll -XPolymorphicComponents
-XNoPolymorphicComponents -XRank2Types -XNoRank2Types -XRankNTypes -XNoRankNTypes
-XImpredicativeTypes -XNoImpredicativeTypes -XExistentialQuantification
-XNoExistentialQuantification -XKindSignatures -XNoKindSignatures -XEmptyDataDecls
-XNoEmptyDataDecls -XParallelListComp -XNoParallelListComp -XTransformListComp
-XNoTransformListComp -XMonadComprehensions -XNoMonadComprehensions -XUnliftedFFITypes
-XNoUnliftedFFITypes -XInterruptibleFFI -XNoInterruptibleFFI -XLiberalTypeSynonyms
-XNoLiberalTypeSynonyms -XTypeOperators -XNoTypeOperators -XExplicitNamespaces
-XNoExplicitNamespaces -XRecursiveDo -XNoRecursiveDo -XParallelArrays -XNoParallelArrays
-XRecordWildCards -XNoRecordWildCards -XNamedFieldPuns -XNoNamedFieldPuns
-XDisambiguateRecordFields -XNoDisambiguateRecordFields -XUnboxedTuples -XNoUnboxedTuples
-XStandaloneDeriving -XNoStandaloneDeriving -XDeriveDataTypeable -XNoDeriveDataTypeable
-XDeriveGeneric -XNoDeriveGeneric -XGeneralizedNewtypeDeriving
-XNoGeneralizedNewtypeDeriving -XTypeSynonymInstances -XNoTypeSynonymInstances
-XFlexibleContexts -XNoFlexibleContexts -XFlexibleInstances -XNoFlexibleInstances
-XConstrainedClassMethods -XNoConstrainedClassMethods -XDefaultSignatures
-XNoDefaultSignatures -XMultiParamTypeClasses -XNoMultiParamTypeClasses
-XFunctionalDependencies -XNoFunctionalDependencies -XPackageImports -XNoPackageImports
-XLambdaCase -XNoLambdaCase -XMultiWayIf -XNoMultiWayIf -XSafe -XTrustworthy -XUnsafe
-fpackage-trust
Warnings
-W -w -w -Wall -w -Werror -Wwarn -fdefer-type-errors -fno-defer-type-errors
-fhelpful-errors -fno-helpful-errors -fwarn-deprecated-flags -fno-warn-deprecated-flags
-fwarn-duplicate-exports -fno-warn-duplicate-exports -fwarn-hi-shadowing
-fno-warn-hi-shadowing -fwarn-identities -fno-warn-identities -fwarn-implicit-prelude
-fno-warn-implicit-prelude -fwarn-incomplete-patterns -fno-warn-incomplete-patterns
-fwarn-incomplete-uni-patterns -fno-warn-incomplete-uni-patterns
-fwarn-incomplete-record-updates -fno-warn-incomplete-record-updates
-fwarn-lazy-unlifted-bindings -fno-warn-lazy-unlifted-bindings -fwarn-missing-fields
-fno-warn-missing-fields -fwarn-missing-import-lists -fnowarn-missing-import-lists
-fwarn-missing-methods -fno-warn-missing-methods -fwarn-missing-signatures
-fno-warn-missing-signatures -fwarn-missing-local-sigs -fno-warn-missing-local-sigs
-fwarn-monomorphism-restriction -fno-warn-monomorphism-restriction -fwarn-name-shadowing
-fno-warn-name-shadowing -fwarn-orphans, -fwarn-auto-orphans -fno-warn-orphans,
-fno-warn-auto-orphans -fwarn-overlapping-patterns -fno-warn-overlapping-patterns
-fwarn-tabs -fno-warn-tabs -fwarn-type-defaults -fno-warn-type-defaults
-fwarn-unrecognised-pragmas -fno-warn-unrecognised-pragmas -fwarn-unused-binds
-fno-warn-unused-binds -fwarn-unused-imports -fno-warn-unused-imports
-fwarn-unused-matches -fno-warn-unused-matches -fwarn-unused-do-bind
-fno-warn-unused-do-bind -fwarn-wrong-do-bind -fno-warn-wrong-do-bind -fwarn-unsafe
-fno-warn-unsafe -fwarn-safe -fno-warn-safe -fwarn-warnings-deprecations
-fno-warn-warnings-deprecations
Optimisation levels
-O -O0 -On -O0
Individual optimisations
-fcase-merge -fno-case-merge -fcse -fdicts-strict -fno-dicts-strict -fdo-eta-reduction
-fno-do-eta-reduction -fdo-lambda-eta-expansion -fno-do-lambda-eta-expansion
-feager-blackholing -fenable-rewrite-rules -fno-enable-rewrite-rules -fvectorise
-fno-vectorise -favoid-vect -fno-avoid-vect -fexcess-precision -fno-excess-precision
-ffloat-in -ffull-laziness -fignore-asserts -fno-ignore-asserts
-fignore-interface-pragmas -fno-ignore-interface-pragmas -fliberate-case
-fliberate-case-threshold=n -fno-liberate-case-threshold -fmax-simplifier-iterations
-fmax-worker-args -fno-opt-coercion -fno-pre-inlining -fno-state-hack
-fpedantic-bottoms -fno-pedantic-bottoms -fomit-interface-pragmas
-fno-omit-interface-pragmas -fsimplifier-phases -fsimpl-tick-factor=n -fspec-constr
-fspec-constr-threshold=n -fno-spec-constr-threshold -fspec-constr-count=n
-fno-spec-constr-count -fspecialise -fstrictness -fstrictness=before=n
-fstatic-argument-transformation -funbox-strict-fields -fno-unbox-strict-fields
-funfolding-creation-threshold -fno-unfolding-creation-threshold -funfolding-fun-discount
-fno-unfolding-fun-discount -funfolding-keeness-factor -fno-unfolding-keeness-factor
-funfolding-use-threshold -fno-unfolding-use-threshold
Profiling options
-prof -fprof-auto -fno-prof-auto -fprof-auto-top -fno-prof-auto -fprof-auto-exported
-fno-prof-auto -fprof-cafs -fno-prof-cafs -fno-prof-count-entries -fprof-count-entries
-ticky
Program coverage options
-fhpc -hpcdir dir
Haskell pre-processor options
-F
C pre-processor options
-cpp -Dsymbol=value -U -Usymbol -Idir
Code generation options
-fasm -fllvm -fno-code -fbyte-code -fobject-code
Linking options
-shared -fPIC -dynamic -dynload -framework name -framework-path name -llib -Ldir
-main-is --mk-dll -no-hs-main -rtsopts, -rtsopts={none,some,all} -with-rtsopts=opts
-no-link -split-objs -static -threaded -debug -eventlog -fno-gen-manifest
-fno-embed-manifest -fno-shared-implib -dylib-install-name path
Plugin options
-fplugin=module -fplugin-opt=module:args
Replacing phases
-pgmL cmd -pgmP cmd -pgmc cmd -pgms cmd -pgma cmd -pgml cmd -pgmdll cmd -pgmF cmd
-pgmwindres cmd
Forcing options to particular phases
-optL option -optP option -optF option -optc option -optlo option -optlc option
-optm option -opta option -optl option -optdll option -optwindres option
Platform-specific options
-msse2 -monly-[432]-regs
External core file options
-fext-core
Compiler debugging options
-dcore-lint -ddump-to-file -ddump-asm -ddump-bcos -ddump-cmm -ddump-core-stats
-ddump-cpranal -ddump-cse -ddump-deriv -ddump-ds -ddump-flatC -ddump-foreign
-ddump-hpc -ddump-inlinings -ddump-llvm -ddump-occur-anal -ddump-opt-cmm
-ddump-parsed -ddump-prep -ddump-rn -ddump-rule-firings -ddump-rule-rewrites
-ddump-rules -ddump-vect -ddump-simpl -ddump-simpl-phases -ddump-simpl-iterations
-ddump-spec -ddump-splices -ddump-stg -ddump-stranal -ddump-tc -ddump-types
-ddump-worker-wrapper -ddump-if-trace -ddump-tc-trace -ddump-vt-trace -ddump-rn-trace
-ddump-rn-stats -ddump-simpl-stats -dno-debug-output -dppr-debug -dppr-noprags
-dppr-user-length -dppr-colsNNN -dppr-case-as-let -dsuppress-all -dsuppress-uniques
-dsuppress-idinfo -dsuppress-module-prefixes -dsuppress-type-signatures
-dsuppress-type-applications -dsuppress-coercions -dsource-stats -dcmm-lint -dstg-lint
-dstg-stats -dverbose-core2core -dverbose-stg2stg -dshow-passes -dfaststring-stats
Misc compiler options
-fno-hi-version-check -dno-black-holing -fhistory-size -funregisterised
-fno-ghci-history -fno-ghci-sandbox
HELP AND VERBOSITY OPTIONS
-? help
[mode]
-help help
[mode]
-v verbose mode (equivalent to -v3)
[dynamic]
-vn set verbosity level
[dynamic]
-V display GHC version
[mode]
--supported-extensions or --supported-languages
display the supported languages and language extensions
[mode]
--info display information about the compiler
[mode]
--version
display GHC version
[mode]
--numeric-version
display GHC version (numeric only)
[mode]
--print-libdir
display GHC library directory
[mode]
-ferror-spans
output full span in error messages
[static]
-Hsize Set the minimum heap size to size
[static]
-Rghc-timing
Summarise timing stats for GHC (same as +RTS -tstderr)
[static]
WHICH PHASES TO RUN
-E Stop after preprocessing (.hspp file)
[mode]
-C Stop after generating C (.hc file)
[mode]
-S Stop after generating assembly (.s file)
[mode]
-c Do not link
[dynamic]
-x suffix
Override default behaviour for source files
[static]
ALTERNATIVE MODES OF OPERATION
--interactive
Interactive mode - normally used by just running ghci; see for details.
[mode]
--make Build a multi-module Haskell program, automatically figuring out dependencies.
Likely to be much easier, and faster, than using make; see for details..
[mode]
-e expr
Evaluate expr; see for details.
[mode]
-M Generate dependency information suitable for use in a Makefile; see for details.
[mode]
REDIRECTING OUTPUT
-hcsuf suffix
set the suffix to use for intermediate C files
[dynamic]
-hidir dir
set directory for interface files
[dynamic]
-hisuf suffix
set the suffix to use for interface files
[dynamic]
-o filename
set output filename
[dynamic]
-odir dir
set directory for object files
[dynamic]
-ohi filename
set the filename in which to put the interface
[dynamic]
-osuf suffix
set the output file suffix
[dynamic]
-stubdir dir
redirect FFI stub files
[dynamic]
-dumpdir dir
redirect dump files
[dynamic]
-outputdir dir
set output directory
[dynamic]
KEEPING INTERMEDIATE FILES
-keep-hc-file or
-keep-hc-files retain intermediate .hc files
[dynamic]
-keep-llvm-file or
-keep-llvm-files retain intermediate LLVM .ll files
[dynamic]
-keep-s-file or
-keep-s-files retain intermediate .s files
[dynamic]
-keep-tmp-files
retain all intermediate temporary files
[dynamic]
TEMPORARY FILES
-tmpdir
set the directory for temporary files
[dynamic]
FINDING IMPORTS
-idir1:dir2:...
add dir, dir2, etc. to import path
[static/:set]
-i Empty the import directory list
[static/:set]
INTERFACE FILE OPTIONS
-ddump-hi
Dump the new interface to stdout
[dynamic]
-ddump-hi-diffs
Show the differences vs. the old interface
[dynamic]
-ddump-minimal-imports
Dump a minimal set of imports
[dynamic]
--show-iface file
See .
[]
RECOMPILATION CHECKING
-fforce-recomp
Turn off recompilation checking; implied by any -ddump-X option
[dynamic]
INTERACTIVE-MODE OPTIONS
-ignore-dot-ghci
Disable reading of .ghci files
[dynamic]
-ghci-script
Read additional .ghci files
[dynamic]
-fbreak-on-exception
Break on any exception thrown
[dynamic]
-fbreak-on-error
Break on uncaught exceptions and errors
[dynamic]
-fprint-evld-with-show
Enable usage of Show instances in :print
[dynamic]
-fprint-bind-result
Turn on printing of binding results in GHCi
[dynamic]
-fno-print-bind-contents
Turn off printing of binding contents in GHCi
[dynamic]
-fno-implicit-import-qualified
Turn off implicit qualified import of everything in GHCi
[dynamic]
-interactive-print
Select the function to use for printing evaluated expressions in GHCi
[dynamic]
PACKAGES
-package-name P
Compile to be part of package P
[static]
-package P
Expose package P
[static/:set]
-hide-all-packages
Hide all packages by default
[static]
-hide-package name
Hide package P
[static/:set]
-ignore-package name
Ignore package P
[static/:set]
-package-db file
Add file to the package db stack.
[static]
-clear-package-db
Clear the package db stack.
[static]
-no-global-package-db
Remove the global package db from the stack.
[static]
-global-package-db
Add the global package db to the stack.
[static]
-no-user-package-db
Remove the user's package db from the stack.
[static]
-user-package-db
Add the user's package db to the stack.
[static]
-no-auto-link-packages
Don't automatically link in the haskell98 package.
[dynamic]
-trust P
Expose package P and set it to be trusted
[static/:set]
-distrust P
Expose package P and set it to be distrusted
[static/:set]
-distrust-all
Distrust all packages by default
[static/:set]
LANGUAGE OPTIONS
-fglasgow-exts
Enable most language extensions; see for exactly which ones.
[dynamic]
-XOverlappingInstances
Enable overlapping instances
[dynamic]
-XIncoherentInstances
Enable incoherent instances. Implies -XOverlappingInstances
[dynamic]
-XUndecidableInstances
Enable undecidable instances
[dynamic]
-fcontext-stack=Nn
set the limit for context reduction. Default is 20.
[dynamic]
-XArrows
Enable arrow notation extension
[dynamic]
-XDisambiguateRecordFields
Enable record field disambiguation
[dynamic]
-XForeignFunctionInterface
Enable foreign function interface (implied by -fglasgow-exts)
[dynamic]
-XGenerics
Deprecated, does nothing. No longer enables generic classes. See also GHC's support
for generic programming.
[dynamic]
-XImplicitParams
Enable Implicit Parameters. Implied by -fglasgow-exts.
[dynamic]
-firrefutable-tuples
Make tuple pattern matching irrefutable
[dynamic]
-XNoImplicitPrelude
Don't implicitly import Prelude
[dynamic]
-XRebindableSyntax
Employ rebindable syntax
[dynamic]
-XNoMonomorphismRestriction
Disable the monomorphism restriction
[dynamic]
-XNoNPlusKPatterns
Disable support for n+k patterns
[dynamic]
-XNoTraditionalRecordSyntax
Disable support for traditional record syntax (as supported by Haskell 98) C {f =
x}
[dynamic]
-XNoMonoPatBinds
Make pattern bindings polymorphic
[dynamic]
-XRelaxedPolyRec
Relaxed checking for mutually-recursive polymorphic functions
[dynamic]
-XExtendedDefaultRules
Use GHCi's extended default rules in a normal module
[dynamic]
-XOverloadedStrings
Enable overloaded string literals.
[dynamic]
-XGADTs
Enable generalised algebraic data types.
[dynamic]
-XGADTSyntax
Enable generalised algebraic data type syntax.
[dynamic]
-XTypeFamilies
Enable type families.
[dynamic]
-XConstraintKinds
Enable a kind of constraints.
[dynamic]
-XDataKinds
Enable datatype promotion.
[dynamic]
-XPolyKinds
Enable kind polymorphism. Implies -XKindSignatures.
[dynamic]
-XScopedTypeVariables
Enable lexically-scoped type variables. Implied by -fglasgow-exts.
[dynamic]
-XMonoLocalBinds
Enable do not generalise local bindings.
[dynamic]
-XTemplateHaskell
Enable Template Haskell. No longer implied by -fglasgow-exts.
[dynamic]
-XQuasiQuotes
Enable quasiquotation.
[dynamic]
-XBangPatterns
Enable bang patterns.
[dynamic]
-XCPP Enable the C preprocessor.
[dynamic]
-XPatternGuards
Enable pattern guards.
[dynamic]
-XViewPatterns
Enable view patterns.
[dynamic]
-XUnicodeSyntax
Enable unicode syntax.
[dynamic]
-XMagicHash
Allow "#" as a postfix modifier on identifiers.
[dynamic]
-XExplicitForAll
Enable explicit universal quantification. Implied by -XScopedTypeVariables,
-XLiberalTypeSynonyms, -XRank2Types, -XRankNTypes, -XPolymorphicComponents,
-XExistentialQuantification
[dynamic]
-XPolymorphicComponents
Enable polymorphic components for data constructors.
[dynamic]
-XRank2Types
Enable rank-2 types.
[dynamic]
-XRankNTypes
Enable rank-N types.
[dynamic]
-XImpredicativeTypes
Enable impredicative types.
[dynamic]
-XExistentialQuantification
Enable existential quantification.
[dynamic]
-XKindSignatures
Enable kind signatures.
[dynamic]
-XEmptyDataDecls
Enable empty data declarations.
[dynamic]
-XParallelListComp
Enable parallel list comprehensions.
[dynamic]
-XTransformListComp
Enable generalised list comprehensions.
[dynamic]
-XMonadComprehensions
Enable monad comprehensions.
[dynamic]
-XUnliftedFFITypes
Enable unlifted FFI types.
[dynamic]
-XInterruptibleFFI
Enable interruptible FFI.
[dynamic]
-XLiberalTypeSynonyms
Enable liberalised type synonyms.
[dynamic]
-XTypeOperators
Enable type operators.
[dynamic]
-XExplicitNamespaces
Enable using the keyword type to specify the namespace of entries in imports and
exports.
[dynamic]
-XRecursiveDo
Enable recursive do (mdo) notation.
[dynamic]
-XParallelArrays
Enable parallel arrays.
[dynamic]
-XRecordWildCards
Enable record wildcards.
[dynamic]
-XNamedFieldPuns
Enable record puns.
[dynamic]
-XDisambiguateRecordFields
Enable record field disambiguation.
[dynamic]
-XUnboxedTuples
Enable unboxed tuples.
[dynamic]
-XStandaloneDeriving
Enable standalone deriving.
[dynamic]
-XDeriveDataTypeable
Enable deriving for the Data and Typeable classes.
[dynamic]
-XDeriveGeneric
Enable deriving for the Generic class.
[dynamic]
-XGeneralizedNewtypeDeriving
Enable newtype deriving.
[dynamic]
-XTypeSynonymInstances
Enable type synonyms in instance heads.
[dynamic]
-XFlexibleContexts
Enable flexible contexts.
[dynamic]
-XFlexibleInstances
Enable flexible instances. Implies -XTypeSynonymInstances
[dynamic]
-XConstrainedClassMethods
Enable constrained class methods.
[dynamic]
-XDefaultSignatures
Enable default signatures.
[dynamic]
-XMultiParamTypeClasses
Enable multi parameter type classes.
[dynamic]
-XFunctionalDependencies
Enable functional dependencies.
[dynamic]
-XPackageImports
Enable package-qualified imports.
[dynamic]
-XLambdaCase
Enable lambda-case expressions.
[dynamic]
-XMultiWayIf
Enable multi-way if-expressions.
[dynamic]
-XSafe Enable the Safe Haskell Safe mode.
[dynamic]
-XTrustworthy
Enable the Safe Haskell Trustworthy mode.
[dynamic]
-XUnsafe
Enable Safe Haskell Unsafe mode.
[dynamic]
-fpackage-trust
Enable Safe Haskell trusted package requirement for trustworty modules.
[dynamic]
WARNINGS
-W enable normal warnings
[dynamic]
-w disable all warnings
[dynamic]
-Wall enable almost all warnings (details in )
[dynamic]
-Werror
make warnings fatal
[dynamic]
-Wwarn make warnings non-fatal
[dynamic]
-fdefer-type-errors
Defer as many type errors as possible until runtime.
[dynamic]
-fhelpful-errors
Make suggestions for mis-spelled names.
[dynamic]
-fwarn-deprecated-flags
warn about uses of commandline flags that are deprecated
[dynamic]
-fwarn-duplicate-exports
warn when an entity is exported multiple times
[dynamic]
-fwarn-hi-shadowing
warn when a .hi file in the current directory shadows a library
[dynamic]
-fwarn-identities
warn about uses of Prelude numeric conversions that are probably the identity (and
hence could be omitted)
[dynamic]
-fwarn-implicit-prelude
warn when the Prelude is implicitly imported
[dynamic]
-fwarn-incomplete-patterns
warn when a pattern match could fail
[dynamic]
-fwarn-incomplete-uni-patterns
warn when a pattern match in a lambda expression or pattern binding could fail
[dynamic]
-fwarn-incomplete-record-updates
warn when a record update could fail
[dynamic]
-fwarn-lazy-unlifted-bindings
warn when a pattern binding looks lazy but must be strict
[dynamic]
-fwarn-missing-fields
warn when fields of a record are uninitialised
[dynamic]
-fwarn-missing-import-lists
warn when an import declaration does not explicitly list all the names brought into
scope
[dynamic]
-fwarn-missing-methods
warn when class methods are undefined
[dynamic]
-fwarn-missing-signatures
warn about top-level functions without signatures
[dynamic]
-fwarn-missing-local-sigs
warn about polymorphic local bindings without signatures
[dynamic]
-fwarn-monomorphism-restriction
warn when the Monomorphism Restriction is applied
[dynamic]
-fwarn-name-shadowing
warn when names are shadowed
[dynamic]
-fwarn-orphans, -fwarn-auto-orphans
warn when the module contains orphan instance declarations or rewrite rules
[dynamic]
-fwarn-overlapping-patterns
warn about overlapping patterns
[dynamic]
-fwarn-tabs
warn if there are tabs in the source file
[dynamic]
-fwarn-type-defaults
warn when defaulting happens
[dynamic]
-fwarn-unrecognised-pragmas
warn about uses of pragmas that GHC doesn't recognise
[dynamic]
-fwarn-unused-binds
warn about bindings that are unused
[dynamic]
-fwarn-unused-imports
warn about unnecessary imports
[dynamic]
-fwarn-unused-matches
warn about variables in patterns that aren't used
[dynamic]
-fwarn-unused-do-bind
warn about do bindings that appear to throw away values of types other than ()
[dynamic]
-fwarn-wrong-do-bind
warn about do bindings that appear to throw away monadic values that you should
have bound instead
[dynamic]
-fwarn-unsafe
warn if the module being compiled is regarded to be unsafe. Should be used to check
the safety status of modules when using safe inference.
[dynamic]
-fwarn-safe
warn if the module being compiled is regarded to be safe. Should be used to check
the safety status of modules when using safe inference.
[dynamic]
-fwarn-warnings-deprecations
warn about uses of functions & types that have warnings or deprecated pragmas
[dynamic]
OPTIMISATION LEVELS
-O Enable default optimisation (level 1)
[dynamic]
-On Set optimisation level n
[dynamic]
INDIVIDUAL OPTIMISATIONS
-fcase-merge
Enable case-merging. Implied by -O.
[dynamic]
-fcse Turn on common sub-expression elimination. Implied by -O.
[dynamic]
-fdicts-strict
Make dictionaries strict
[static]
-fdo-eta-reduction
Enable eta-reduction. Implied by -O.
[dynamic]
-fdo-lambda-eta-expansion
Enable lambda eta-reduction
[dynamic]
-feager-blackholing
Turn on eager blackholing
[dynamic]
-fenable-rewrite-rules
Switch on all rewrite rules (including rules generated by automatic specialisation
of overloaded functions). Implied by -O.
[dynamic]
-fvectorise
Enable vectorisation of nested data parallelism
[dynamic]
-favoid-vect
Enable vectorisation avoidance (EXPERIMENTAL)
[dynamic]
-fexcess-precision
Enable excess intermediate precision
[dynamic]
-ffloat-in
Turn on the float-in transformation. Implied by -O.
[dynamic]
-ffull-laziness
Turn on full laziness (floating bindings outwards). Implied by -O.
[dynamic]
-fignore-asserts
Ignore assertions in the source
[dynamic]
-fignore-interface-pragmas
Ignore pragmas in interface files
[dynamic]
-fliberate-case
Turn on the liberate-case transformation. Implied by -O2.
[dynamic]
-fliberate-case-threshold=n
Set the size threshold for the liberate-case transformation to n (default: 200)
[static]
-fmax-simplifier-iterations
Set the max iterations for the simplifier
[dynamic]
-fmax-worker-args
If a worker has that many arguments, none will be unpacked anymore (default: 10)
[static]
-fno-opt-coercion
Turn off the coercion optimiser
[static]
-fno-pre-inlining
Turn off pre-inlining
[static]
-fno-state-hack
Turn off the "state hack" whereby any lambda with a real-world state token as
argument is considered to be single-entry. Hence OK to inline things inside it.
[static]
-fpedantic-bottoms
Make GHC be more precise about its treatment of bottom (but see also
-fno-state-hack). In particular, GHC will not eta-expand through a case expression.
[dynamic]
-fomit-interface-pragmas
Don't generate interface pragmas
[dynamic]
-fsimplifier-phases
Set the number of phases for the simplifier (default 2). Ignored with -O0.
[dynamic]
-fsimpl-tick-factor=n
Set the percentage factor for simplifier ticks (default 100)
[dynamic]
-fspec-constr
Turn on the SpecConstr transformation. Implied by -O2.
[dynamic]
-fspec-constr-threshold=n
Set the size threshold for the SpecConstr transformation to n (default: 200)
[static]
-fspec-constr-count=n
Set to n (default: 3) the maximum number of specialisations that will be created
for any one function by the SpecConstr transformation
[static]
-fspecialise
Turn on specialisation of overloaded functions. Implied by -O.
[dynamic]
-fstrictness
Turn on strictness analysis. Implied by -O.
[dynamic]
-fstrictness=before=n
Run an additional strictness analysis before simplifier phase n
[dynamic]
-fstatic-argument-transformation
Turn on the static argument transformation. Implied by -O2.
[dynamic]
-funbox-strict-fields
Flatten strict constructor fields
[dynamic]
-funfolding-creation-threshold
Tweak unfolding settings
[static]
-funfolding-fun-discount
Tweak unfolding settings
[static]
-funfolding-keeness-factor
Tweak unfolding settings
[static]
-funfolding-use-threshold
Tweak unfolding settings
[static]
PROFILING OPTIONS
-prof Turn on profiling
[static]
-fprof-auto
Auto-add SCCs to all bindings not marked INLINE
[dynamic]
-fprof-auto-top
Auto-add SCCs to all top-level bindings not marked INLINE
[dynamic]
-fprof-auto-exported
Auto-add SCCs to all exported bindings not marked INLINE
[dynamic]
-fprof-cafs
Auto-add SCCs to all CAFs
[dynamic]
-fno-prof-count-entries
Do not collect entry counts
[dynamic]
-ticky Turn on ticky-ticky profiling
[static]
PROGRAM COVERAGE OPTIONS
-fhpc Turn on Haskell program coverage instrumentation
[static]
-hpcdir dir
Directory to deposit .mix files during compilation (default is .hpc)
[dynamic]
HASKELL PRE-PROCESSOR OPTIONS
-F Enable the use of a pre-processor (set with -pgmF)
[dynamic]
C PRE-PROCESSOR OPTIONS
-cpp Run the C pre-processor on Haskell source files
[dynamic]
-Dsymbol=value
Define a symbol in the C pre-processor
[dynamic]
-Usymbol
Undefine a symbol in the C pre-processor
[dynamic]
-Idir Add dir to the directory search list for #include files
[dynamic]
CODE GENERATION OPTIONS
-fasm Use the native code generator
[dynamic]
-fllvm Compile using the LLVM code generator
[dynamic]
-fno-code
Omit code generation
[dynamic]
-fbyte-code
Generate byte-code
[dynamic]
-fobject-code
Generate object code
[dynamic]
LINKING OPTIONS
-shared
Generate a shared library (as opposed to an executable)
[dynamic]
-fPIC Generate position-independent code (where available)
[static]
-dynamic
Use dynamic Haskell libraries (if available)
[static]
-dynload
Selects one of a number of modes for finding shared libraries at runtime.
[static]
-framework name
On Darwin/MacOS X only, link in the framework name. This option corresponds to the
-framework option for Apple's Linker.
[dynamic]
-framework-path name
On Darwin/MacOS X only, add dir to the list of directories searched for frameworks.
This option corresponds to the -F option for Apple's Linker.
[dynamic]
-llib Link in library lib
[dynamic]
-Ldir Add dir to the list of directories searched for libraries
[dynamic]
-main-is
Set main module and function
[dynamic]
--mk-dll
DLL-creation mode (Windows only)
[dynamic]
-no-hs-main
Don't assume this program contains main
[dynamic]
-rtsopts, -rtsopts={none,some,all}
Control whether the RTS behaviour can be tweaked via command-line flags and the
GHCRTS environment variable. Using none means no RTS flags can be given; some means
only a minimum of safe options can be given (the default), and all (or no argument
at all) means that all RTS flags are permitted.
[dynamic]
-with-rtsopts=opts
Set the default RTS options to opts.
[dynamic]
-no-link
Omit linking
[dynamic]
-split-objs
Split objects (for libraries)
[dynamic]
-static
Use static Haskell libraries
[static]
-threaded
Use the threaded runtime
[static]
-debug Use the debugging runtime
[static]
-eventlog
Enable runtime event tracing
[static]
-fno-gen-manifest
Do not generate a manifest file (Windows only)
[dynamic]
-fno-embed-manifest
Do not embed the manifest in the executable (Windows only)
[dynamic]
-fno-shared-implib
Don't generate an import library for a DLL (Windows only)
[dynamic]
-dylib-install-name path
Set the install name (via -install_name passed to Apple's linker), specifying the
full install path of the library file. Any libraries or executables that link with
it later will pick up that path as their runtime search location for it.
(Darwin/MacOS X only)
[dynamic]
PLUGIN OPTIONS
-fplugin=module
Load a plugin exported by a given module
[static]
-fplugin-opt=module:args
Give arguments to a plugin module; module must be specified with -fplugin
[static]
REPLACING PHASES
-pgmL cmd
Use cmd as the literate pre-processor
[dynamic]
-pgmP cmd
Use cmd as the C pre-processor (with -cpp only)
[dynamic]
-pgmc cmd
Use cmd as the C compiler
[dynamic]
-pgms cmd
Use cmd as the splitter
[dynamic]
-pgma cmd
Use cmd as the assembler
[dynamic]
-pgml cmd
Use cmd as the linker
[dynamic]
-pgmdll cmd
Use cmd as the DLL generator
[dynamic]
-pgmF cmd
Use cmd as the pre-processor (with -F only)
[dynamic]
-pgmwindres cmd
Use cmd as the program for embedding manifests on Windows.
[dynamic]
FORCING OPTIONS TO PARTICULAR PHASES
-optL option
pass option to the literate pre-processor
[dynamic]
-optP option
pass option to cpp (with -cpp only)
[dynamic]
-optF option
pass option to the custom pre-processor
[dynamic]
-optc option
pass option to the C compiler
[dynamic]
-optlo option
pass option to the LLVM optimiser
[dynamic]
-optlc option
pass option to the LLVM compiler
[dynamic]
-optm option
pass option to the mangler
[dynamic]
-opta option
pass option to the assembler
[dynamic]
-optl option
pass option to the linker
[dynamic]
-optdll option
pass option to the DLL generator
[dynamic]
-optwindres option
pass option to windres.
[dynamic]
PLATFORM-SPECIFIC OPTIONS
-msse2 (x86 only) Use SSE2 for floating point
[dynamic]
-monly-[432]-regs
(x86 only) give some registers back to the C compiler
[dynamic]
EXTERNAL CORE FILE OPTIONS
-fext-core
Generate .hcr external Core files
[dynamic]
COMPILER DEBUGGING OPTIONS
-dcore-lint
Turn on internal sanity checking
[dynamic]
-ddump-to-file
Dump to files instead of stdout
[dynamic]
-ddump-asm
Dump assembly
[dynamic]
-ddump-bcos
Dump interpreter byte code
[dynamic]
-ddump-cmm
Dump C-- output
[dynamic]
-ddump-core-stats
Print a one-line summary of the size of the Core program at the end of the
optimisation pipeline
[dynamic]
-ddump-cpranal
Dump output from CPR analysis
[dynamic]
-ddump-cse
Dump CSE output
[dynamic]
-ddump-deriv
Dump deriving output
[dynamic]
-ddump-ds
Dump desugarer output
[dynamic]
-ddump-flatC
Dump `flat' C
[dynamic]
-ddump-foreign
Dump foreign export stubs
[dynamic]
-ddump-hpc
Dump after instrumentation for program coverage
[dynamic]
-ddump-inlinings
Dump inlining info
[dynamic]
-ddump-llvm
Dump LLVM intermediate code
[dynamic]
-ddump-occur-anal
Dump occurrence analysis output
[dynamic]
-ddump-opt-cmm
Dump the results of C-- to C-- optimising passes
[dynamic]
-ddump-parsed
Dump parse tree
[dynamic]
-ddump-prep
Dump prepared core
[dynamic]
-ddump-rn
Dump renamer output
[dynamic]
-ddump-rule-firings
Dump rule firing info
[dynamic]
-ddump-rule-rewrites
Dump detailed rule firing info
[dynamic]
-ddump-rules
Dump rules
[dynamic]
-ddump-vect
Dump vectoriser input and output
[dynamic]
-ddump-simpl
Dump final simplifier output
[dynamic]
-ddump-simpl-phases
Dump output from each simplifier phase
[dynamic]
-ddump-simpl-iterations
Dump output from each simplifier iteration
[dynamic]
-ddump-spec
Dump specialiser output
[dynamic]
-ddump-splices
Dump TH spliced expressions, and what they evaluate to
[dynamic]
-ddump-stg
Dump final STG
[dynamic]
-ddump-stranal
Dump strictness analyser output
[dynamic]
-ddump-tc
Dump typechecker output
[dynamic]
-ddump-types
Dump type signatures
[dynamic]
-ddump-worker-wrapper
Dump worker-wrapper output
[dynamic]
-ddump-if-trace
Trace interface files
[dynamic]
-ddump-tc-trace
Trace typechecker
[dynamic]
-ddump-vt-trace
Trace vectoriser
[dynamic]
-ddump-rn-trace
Trace renamer
[dynamic]
-ddump-rn-stats
Renamer stats
[dynamic]
-ddump-simpl-stats
Dump simplifier stats
[dynamic]
-dno-debug-output
Suppress unsolicited debugging output
[static]
-dppr-debug
Turn on debug printing (more verbose)
[static]
-dppr-noprags
Don't output pragma info in dumps
[static]
-dppr-user-length
Set the depth for printing expressions in error msgs
[dynamic]
-dppr-colsNNN
Set the width of debugging output. For example -dppr-cols200
[dynamic]
-dppr-case-as-let
Print single alternative case expressions as strict lets.
[dynamic]
-dsuppress-all
In core dumps, suppress everything that is suppressable.
[static]
-dsuppress-uniques
Suppress the printing of uniques in debug output (easier to use diff)
[static]
-dsuppress-idinfo
Suppress extended information about identifiers where they are bound
[static]
-dsuppress-module-prefixes
Suppress the printing of module qualification prefixes
[static]
-dsuppress-type-signatures
Suppress type signatures
[static]
-dsuppress-type-applications
Suppress type applications
[static]
-dsuppress-coercions
Suppress the printing of coercions in Core dumps to make them shorter
[static]
-dsource-stats
Dump haskell source stats
[dynamic]
-dcmm-lint
C-- pass sanity checking
[dynamic]
-dstg-lint
STG pass sanity checking
[dynamic]
-dstg-stats
Dump STG stats
[dynamic]
-dverbose-core2core
Show output from each core-to-core pass
[dynamic]
-dverbose-stg2stg
Show output from each STG-to-STG pass
[dynamic]
-dshow-passes
Print out each pass name as it happens
[dynamic]
-dfaststring-stats
Show statistics for fast string usage when finished
[dynamic]
MISC COMPILER OPTIONS
-fno-hi-version-check
Don't complain about .hi file mismatches
[static]
-dno-black-holing
Turn off black holing (probably doesn't work)
[static]
-fhistory-size
Set simplification history size
[static]
-funregisterised
Unregisterised compilation (use -unreg instead)
[static]
-fno-ghci-history
Do not use the load/store the GHCi command history from/to ghci_history.
[dynamic]
-fno-ghci-sandbox
Turn off the GHCi sandbox. Means computations are run in the main thread, rather
than a forked thread.
[dynamic]
FILES
/usr/lib
COPYRIGHT
Copyright 2002, The University Court of the University of Glasgow.
All rights reserved.
AUTHOR
This manual page was generated from the XML documentation of GHC with blood, sweat, tears
and a breaks-if-you-look-at-it-the-wrong-way XSL stylesheet originally written by Michael
Weber <michaelw@debian.org> for the Debian GNU/Linux system (but may be used by others).