GHC

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.