## NAME

GHC - the Glasgow Haskell Compiler

## SYNOPSIS

ghc

ghci

## 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 f(CROPTIONS pragma in a source file or set from the GHCi command-line with f(CR: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]

-v n 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]

-H size Set the minimum heap size to size

[static]

-Rghc-timing Summarise timing stats for GHC (same as f(CR+RTS -tstderr)

[static]

## WHICH PHASES TO RUN

-E Stop after preprocessing (f(CR.hspp file)

[mode]

-C Stop after generating C (f(CR.hc file)

[mode]

-S Stop after generating assembly (f(CR.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 f(CR.hc files

[dynamic]

-keep-llvm-file or -keep-llvm-files retain intermediate LLVM f(CR.ll files

[dynamic]

-keep-s-file or -keep-s-files retain intermediate f(CR.s files

[dynamic]

-keep-tmp-files retain all intermediate temporary files

[dynamic]

## TEMPORARY FILES

-tmpdir set the directory for temporary files

[dynamic]

## FINDING IMPORTS

-i dir1:dir2:... add dir, dir2, etc. to import path

[static/f(CR:set]

-i Empty the import directory list

[static/f(CR: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 f(CR: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/f(CR:set]

-hide-all-packages Hide all packages by default

[static]

-hide-package name Hide package P

[static/f(CR:set]

-ignore-package name Ignore package P

[static/f(CR: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/f(CR:set]

-distrust P Expose package P and set it to be distrusted

[static/f(CR:set]

-distrust-all Distrust all packages by default

[static/f(CR: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=N n 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 f(CRimport Prelude

[dynamic]

-XRebindableSyntax Employ rebindable syntax

[dynamic]

-XNoMonomorphismRestriction Disable the monomorphism restriction

[dynamic]

-XNoNPlusKPatterns Disable support for f(CRn+k patterns

[dynamic]

-XNoTraditionalRecordSyntax Disable support for traditional record syntax (as supported by Haskell 98) f(CRC {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 f(CRtype 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 f(CR.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 f(CR()

[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]

-O n 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 f(CRSCCs to all bindings not marked INLINE

[dynamic]

-fprof-auto-top Auto-add f(CRSCCs to all top-level bindings not marked INLINE

[dynamic]

-fprof-auto-exported Auto-add f(CRSCCs to all exported bindings not marked INLINE

[dynamic]

-fprof-cafs Auto-add f(CRSCCs 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]

-D symbol=value Define a symbol in the C pre-processor

[dynamic]

-U symbol Undefine a symbol in the C pre-processor

[dynamic]

-I dir Add dir to the directory search list for f(CR#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]

-l lib Link in library lib

[dynamic]

-L dir 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 f(CRmain

[dynamic]

-rtsopts, -rtsopts={none,some,all} Control whether the RTS behaviour can be tweaked via command-line flags and the f(CRGHCRTS environment variable. Using f(CRnone means no RTS flags can be given; f(CRsome means only a minimum of safe options can be given (the default), and f(CRall (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 f(CR-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 f(CRwindres.

[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 f(CRforeign 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 f(CR.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 f(CRghci_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).