5.6. Flag reference¶

This section is a quick-reference for GHC’s command-line flags. For each flag, we also list its mode/dynamic status (see Dynamic and Mode options), and the flag’s opposite (if available).

5.6.1. Verbosity options¶

More details in Verbosity options

Flag	Description	Type	Reverse
`-fabstract-refinement-hole-fits`	default: off. Toggles whether refinements where one or more of the holes are abstract are reported.	dynamic	`-fno-abstract-refinement-hole-fits`
`-fdefer-diagnostics`	Defer and group diagnostic messages by severity	dynamic
`-fdiagnostics-as-json`	Output diagnostics in Json format specified by JSON schema	dynamic
`-fdiagnostics-color=⟨always\|auto\|never⟩`	Use colors in error messages	dynamic
`-fdiagnostics-show-caret`	Whether to show snippets of original source code	dynamic	`-fno-diagnostics-show-caret`
`-ferror-spans`	Output full span in error messages	dynamic
`-fhide-source-paths`	hide module source and object paths	dynamic
`-fkeep-going`	Continue compilation as far as possible on errors	dynamic
`-fmax-refinement-hole-fits=⟨n⟩`	default: 6. Set the maximum number of refinement hole fits for typed holes to display in type error messages.	dynamic	`-fno-max-refinement-hole-fits`
`-fmax-relevant-binds=⟨n⟩`	default: 6. Set the maximum number of bindings to display in type error messages.	dynamic	`-fno-max-relevant-binds`
`-fmax-valid-hole-fits=⟨n⟩`	default: 6. Set the maximum number of valid hole fits for typed holes to display in type error messages.	dynamic	`-fno-max-valid-hole-fits`
`-fno-show-valid-hole-fits`	Disables showing a list of valid hole fits for typed holes in type error messages.	dynamic
`-fno-sort-valid-hole-fits`	Disables the sorting of the list of valid hole fits for typed holes in type error messages.	dynamic	`-fsort-valid-hole-fits`
`-fprint-axiom-incomps`	Display equation incompatibilities in closed type families	dynamic	`-fno-print-axiom-incomps`
`-fprint-equality-relations`	Distinguish between equality relations when printing	dynamic	`-fno-print-equality-relations`
`-fprint-error-index-links=⟨always\|auto\|never⟩`	Whether to emit diagnostic codes as ANSI hyperlinks to the Haskell Error Index.	dynamic
`-fprint-expanded-synonyms`	In type errors, also print type-synonym-expanded types.	dynamic	`-fno-print-expanded-synonyms`
`-fprint-explicit-coercions`	Print coercions in types	dynamic	`-fno-print-explicit-coercions`
`-fprint-explicit-foralls`	Print explicit `forall` quantification in types. See also `ExplicitForAll`	dynamic	`-fno-print-explicit-foralls`
`-fprint-explicit-kinds`	Print explicit kind foralls and kind arguments in types. See also `KindSignatures`	dynamic	`-fno-print-explicit-kinds`
`-fprint-explicit-runtime-reps`	Print `RuntimeRep` and `Levity` variables in types which are runtime-representation polymorphic.	dynamic	`-fno-print-explicit-runtime-reps`
`-fprint-potential-instances`	display all available instances in type error messages	dynamic	`-fno-print-potential-instances`
`-fprint-redundant-promotion-ticks`	Print redundant `DataKinds` promotion ticks	dynamic	`-fno-print-redundant-promotion-ticks`
`-fprint-typechecker-elaboration`	Print extra information from typechecker.	dynamic	`-fno-print-typechecker-elaboration`
`-fprint-unicode-syntax`	Use unicode syntax when printing expressions, types and kinds. See also `UnicodeSyntax`	dynamic	`-fno-print-unicode-syntax`
`-frefinement-level-hole-fits=⟨n⟩`	default: off. Sets the level of refinement of the refinement hole fits, where level `n` means that hole fits of up to `n` holes will be considered.	dynamic	`-fno-refinement-level-hole-fits`
`-freverse-errors`	Output errors in reverse order	dynamic	`-fno-reverse-errors`
`-fshow-docs-of-hole-fits`	Toggles whether to show the documentation of the valid hole fits in the output.	dynamic	`-fno-show-docs-of-hole-fits`
`-fshow-error-context`	Whether to show textual information about error context	dynamic	`-fno-show-error-context`
`-fshow-hole-constraints`	Show constraints when reporting typed holes.	dynamic
`-fshow-hole-matches-of-hole-fits`	Toggles whether to show the type of the additional holes in refinement hole fits.	dynamic	`-fno-show-hole-matches-of-hole-fits`
`-fshow-provenance-of-hole-fits`	Toggles whether to show the provenance of the valid hole fits in the output.	dynamic	`-fno-show-provenance-of-hole-fits`
`-fshow-type-app-of-hole-fits`	Toggles whether to show the type application of the valid hole fits in the output.	dynamic	`-fno-show-type-app-of-hole-fits`
`-fshow-type-app-vars-of-hole-fits`	Toggles whether to show what type each quantified variable takes in a valid hole fit.	dynamic	`-fno-show-type-app-vars-of-hole-fits`
`-fshow-type-of-hole-fits`	Toggles whether to show the type of the valid hole fits in the output.	dynamic	`-fno-show-type-of-hole-fits`
`-fsort-by-size-hole-fits`	Sort valid hole fits by size.	dynamic	`-fno-sort-by-size-hole-fits`
`-fsort-by-subsumption-hole-fits`	Sort valid hole fits by subsumption.	dynamic	`-fno-sort-by-subsumption-hole-fits`
`-funclutter-valid-hole-fits`	Unclutter the list of valid hole fits by not showing provenance nor type applications of suggestions.	dynamic
`-Rghc-timing`	Summarise timing stats for GHC (same as `+RTS -tstderr`).	dynamic
`-v`	verbose mode (equivalent to `-v3`)	dynamic
`-v⟨n⟩`	set verbosity level	dynamic

5.6.2. Alternative modes of operation¶

More details in Modes of operation

Flag	Description	Type
`--frontend ⟨module⟩`	run GHC with the given frontend plugin; see Frontend plugins for details.	mode
`--help`, `-?`	Display help	mode
`--info`	display information about the compiler	mode
`--interactive`	Interactive mode - normally used by just running `ghci`; see Using GHCi 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 Using ghc --make for details.	mode
`--numeric-version`	display GHC version (numeric only)	mode
`--print-booter-version`	display bootstrap compiler version	mode
`--print-build-platform`	display platform on which GHC was built	mode
`--print-c-compiler-flags`	C compiler flags used to build GHC	mode
`--print-c-compiler-link-flags`	C linker flags used to build GHC	mode
`--print-debug-on`	print whether GHC was built with `-DDEBUG`	mode
`--print-global-package-db`	display GHC's global package database directory	mode
`--print-have-interpreter`	display whether GHC was built with interactive support	mode
`--print-have-native-code-generator`	display whether target platform has NCG support	mode
`--print-host-platform`	display host platform of GHC	mode
`--print-ld-flags`	display linker flags used to compile GHC	mode
`--print-leading-underscore`	display use of leading underscores on symbol names	mode
`--print-libdir`	display GHC library directory	mode
`--print-object-splitting-supported`	display whether GHC supports object splitting	mode
`--print-project-git-commit-id`	display Git commit id GHC is built from	mode
`--print-project-version`	display GHC version	mode
`--print-rts-ways`	display which way RTS was built	mode
`--print-stage`	display `stage` number of GHC	mode
`--print-support-smp`	display whether GHC was compiled with SMP support	mode
`--print-tables-next-to-code`	display whether GHC was compiled with `--enable-tables-next-to-code`	mode
`--print-target-platform`	display target platform of GHC	mode
`--print-unregisterised`	display whether this GHC was built in unregisterised mode	mode
`--run ⟨file⟩`	Run a Haskell program.	mode
`--show-iface ⟨file⟩`	display the contents of an interface file.	mode
`--show-options`	display the supported command line options	mode
`--supported-extensions`, `--supported-languages`	display the supported language extensions	mode
`--version`, `-V`	display GHC version	mode
`-e ⟨expr⟩`	Evaluate `expr`; see Expression evaluation mode for details.	mode
`-M`	generate dependency information suitable for use in a `Makefile`; see Dependency generation for details.	mode
`-shared`	Create a shared object.	mode

5.6.3. Which phases to run¶

More details in Batch compiler mode

Flag	Description	Type
`--merge-objs`	Merge a set of objects into a GHCi library.	mode
`-C`	Stop after generating C (`.hc` file)	mode
`-c`	Stop after generating object (`.o`) file	mode
`-E`	Stop after preprocessing (`.hspp` file)	mode
`-F`	Enable the use of a pre-processor (set with `-pgmF ⟨cmd⟩`)	dynamic
`-S`	Stop after generating assembly (`.s` file)	mode
`-x ⟨suffix⟩`	Override default behaviour for source files	dynamic

5.6.4. Redirecting output¶

More details in Redirecting the compilation output(s)

Flag	Description	Type
`-dep-makefile ⟨file⟩`	Use ⟨file⟩ as the makefile	dynamic
`-dep-suffix ⟨suffix⟩`	Make dependencies that declare that files with suffix `.⟨suf⟩⟨osuf⟩` depend on interface files with suffix `.⟨suf⟩hi`	dynamic
`-dumpdir ⟨dir⟩`	redirect dump files	dynamic
`-dynhisuf ⟨suffix⟩`	set the suffix to use for dynamic interface files	dynamic
`-dyno ⟨file⟩`	set dynamic output filename	dynamic
`-dynohi ⟨file⟩`	set the filename in which to put the dynamic interface	dynamic
`-dynosuf ⟨suffix⟩`	set the dynamic output file suffix	dynamic
`-hcsuf ⟨suffix⟩`	set the suffix to use for intermediate C files	dynamic
`-hidir ⟨dir⟩`	set directory for interface files	dynamic
`-hiedir ⟨dir⟩`	set directory for extended interface files	dynamic
`-hiesuf ⟨suffix⟩`	set the suffix to use for extended interface files	dynamic
`-hisuf ⟨suffix⟩`	set the suffix to use for interface files	dynamic
`-o ⟨file⟩`	set output filename	dynamic
`-odir ⟨dir⟩`	set directory for object files	dynamic
`-ohi ⟨file⟩`	set the filename in which to put the interface	dynamic
`-osuf ⟨suffix⟩`	set the output file suffix	dynamic
`-outputdir ⟨dir⟩`	set output directory	dynamic
`-stubdir ⟨dir⟩`	redirect FFI stub files	dynamic

5.6.5. Keeping intermediate files¶

More details in Keeping Intermediate Files

Flag	Description	Type	Reverse
`-keep-hc-file`, `-keep-hc-files`	Retain intermediate `.hc` files.	dynamic
`-keep-hi-files`	Retain intermediate `.hi` files (the default).	dynamic	`-no-keep-hi-files`
`-keep-hscpp-file`, `-keep-hscpp-files`	Retain intermediate `.hscpp` files.	dynamic
`-keep-llvm-file`, `-keep-llvm-files`	Retain intermediate LLVM `.ll` files. Implies `-fllvm`.	dynamic
`-keep-o-files`	Retain intermediate `.o` files (the default).	dynamic	`-no-keep-o-files`
`-keep-s-file`, `-keep-s-files`	Retain intermediate `.s` files.	dynamic
`-keep-tmp-files`	Retain all intermediate temporary files.	dynamic

5.6.6. Temporary files¶

More details in Redirecting temporary files

Flag Description Type Reverse

-tmpdir ⟨dir⟩

set the directory for temporary files

dynamic

5.6.7. Finding imports¶

More details in The search path

Flag Description Type Reverse

-i

Empty the import directory list

dynamic

-i⟨dir⟩[:⟨dir⟩]*

add ⟨dir⟩, ⟨dir2⟩, etc. to import path

dynamic

5.6.8. Interface file options¶

More details in Other options related to interface files

Flag	Description	Type
`--show-iface ⟨file⟩`	See Modes of operation.	mode
`-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

5.6.9. Extended interface file options¶

More details in Options related to extended interface files

Flag Description Type Reverse

-fvalidate-ide-info

Perform some sanity checks on the extended interface files

dynamic

-fwrite-ide-info

Write out extended interface files

dynamic

5.6.10. Recompilation checking¶

More details in The recompilation checker

Flag	Description	Type	Reverse
`-exclude-module=⟨file⟩`	Regard `⟨file⟩` as "stable"; i.e., exclude it from having dependencies on it.	dynamic
`-fforce-recomp`	Turn off recompilation checking. This is implied by any `-ddump-X` option when compiling a single file (i.e. when using `-c`).	dynamic	`-fno-force-recomp`
`-fignore-hpc-changes`	Do not recompile modules just to match changes to HPC flags. This is especially useful for avoiding recompilation when using GHCi, and is enabled by default for GHCi.	dynamic	`-fno-ignore-hpc-changes`
`-fignore-optim-changes`	Do not recompile modules just to match changes to optimisation flags. This is especially useful for avoiding recompilation when using GHCi, and is enabled by default for GHCi.	dynamic	`-fno-ignore-optim-changes`
`-include-cpp-deps`	Include preprocessor dependencies	dynamic
`-include-pkg-deps`	Regard modules imported from packages as unstable	dynamic

5.6.11. Interactive-mode options¶

More details in The .ghci and .haskeline files

Flag	Description	Type	Reverse
`-fbreak-on-error`	Break on uncaught exceptions and errors	dynamic	`-fno-break-on-error`
`-fbreak-on-exception`	Break on any exception thrown	dynamic	`-fno-break-on-exception`
`-fbreak-points`	Insert breakpoints in the GHCi debugger	dynamic	`-fno-break-points`
`-fghci-hist-size=⟨n⟩`	Set the number of entries GHCi keeps for `:history`. See The GHCi Debugger.	dynamic
`-fghci-leak-check`	(Debugging only) check for space leaks when loading new modules in GHCi.	dynamic	`-fno-ghci-leak-check`
`-fimplicit-import-qualified`	Put in scope qualified identifiers for every loaded module	dynamic	`-fno-implicit-import-qualified`
`-flocal-ghci-history`	Use current directory for the GHCi command history file `.ghci-history`.	dynamic	`-fno-local-ghci-history`
`-fno-it`	No longer set the special variable `it`.	dynamic	`-fno-no-it`
`-fprint-bind-result`	Turn on printing of binding results in GHCi	dynamic	`-fno-print-bind-result`
`-fprint-evld-with-show`	Instruct `:print` to use `Show` instances where possible.	dynamic
`-fshow-loaded-modules`	Show the names of modules that GHCi loaded after a `:load` command.	dynamic
`-ghci-script`	Read additional `.ghci` files	dynamic
`-ignore-dot-ghci`	Disable reading of `.ghci` files	dynamic	`-no-ignore-dot-ghci`
`-interactive-print ⟨name⟩`	Select the function to use for printing evaluated expressions in GHCi	dynamic

5.6.12. Packages¶

More details in Packages

Flag	Description	Type
`-clear-package-db`	Clear the package db stack.	dynamic
`-distrust ⟨pkg⟩`	Expose package ⟨pkg⟩ and set it to be distrusted. See Safe Haskell.	dynamic
`-distrust-all-packages`	Distrust all packages by default. See Safe Haskell.	dynamic
`-fpackage-trust`	Enable Safe Haskell trusted package requirement for trustworthy modules.	dynamic
`-global-package-db`	Add the global package db to the stack.	dynamic
`-hide-all-packages`	Hide all packages by default	dynamic
`-hide-package ⟨pkg⟩`	Hide package ⟨pkg⟩	dynamic
`-ignore-package ⟨pkg⟩`	Ignore package ⟨pkg⟩	dynamic
`-no-auto-link-packages`	Don't automatically link in the base and rts packages.	dynamic
`-no-global-package-db`	Remove the global package db from the stack.	dynamic
`-no-user-package-db`	Remove the user's package db from the stack.	dynamic
`-package ⟨pkg⟩`	Expose package ⟨pkg⟩	dynamic
`-package-db ⟨file⟩`	Add ⟨file⟩ to the package db stack.	dynamic
`-package-env ⟨file⟩\|⟨name⟩`	Use the specified package environment.	dynamic
`-package-id ⟨unit-id⟩`	Expose package by id ⟨unit-id⟩	dynamic
`-this-unit-id ⟨unit-id⟩`	Compile to be part of unit (i.e. package) ⟨unit-id⟩	dynamic
`-trust ⟨pkg⟩`	Expose package ⟨pkg⟩ and set it to be trusted. See Safe Haskell.	dynamic
`-user-package-db`	Add the user's package db to the stack.	dynamic

5.6.13. Language options¶

Language options can be enabled either by a command-line option -Xblah, or by a {-# LANGUAGE blah #-} pragma in the file itself. See Controlling editions and extensions.

5.6.14. Warnings¶

More details in Warnings and sanity-checking

Flag	Description	Type	Reverse
`-fenable-th-splice-warnings`	Generate warnings for Template Haskell splices	dynamic	`-fno-enable-th-splice-warnings`
`-fhelpful-errors`	Make suggestions for mis-spelled names.	dynamic	`-fno-helpful-errors`
`-fmax-pmcheck-models=⟨n⟩`	soft limit on the number of parallel models the pattern match checker should check a pattern match clause against	dynamic
`-fshow-warning-groups`	show which group an emitted warning belongs to.	dynamic	`-fno-show-warning-groups`
`-fvia-C`	use the C code generator	dynamic
`-W`	enable normal warnings	dynamic	`-Wno-extra`
`-w`	disable all warnings	dynamic
`-Wall`	enable almost all warnings (details in Warnings and sanity-checking)	dynamic	`-Wno-all`
`-Wall-missed-specialisations`	warn when specialisation of any overloaded function fails.	dynamic	`-Wno-all-missed-specialisations`
`-Wall-missed-specializations`	alias for `-Wall-missed-specialisations`	dynamic	`-Wno-all-missed-specializations`
`-Wambiguous-fields`	warn about ambiguous field selectors or updates	dynamic
`-Wauto-orphans`	(deprecated) Does nothing	dynamic
`-Wbadly-staged-types`	warn when type binding is used at the wrong TH stage.	dynamic	`-Wno-badly-staged-types`
`-Wcompat`	enable future compatibility warnings (details in Warnings and sanity-checking)	dynamic	`-Wno-compat`
`-Wcompat-unqualified-imports`	(deprecated) Report unqualified imports of core libraries which are expected to cause compatibility problems in future releases.	dynamic	`-Wno-compat-unqualified-imports`
`-Wcpp-undef`	warn on uses of the #if directive on undefined identifiers	dynamic
`-Wdata-kinds-tc`	warn when an illegal use of a type or kind without `DataKinds` is caught by the typechecker	dynamic	`-Wno-data-kinds-tc`
`-Wdefault`	enable default flags	dynamic	`-Wno-default`
`-Wdefaulted-exception-context`	warn when an Control.Exception.Context.ExceptionContext implicit parameter is defaulted to Control.Exception.Context.emptyExceptionContext.	dynamic	`-Wnop-defaulted-exception-context`
`-Wdeferred-out-of-scope-variables`	Report warnings when variable out-of-scope errors are deferred until runtime. See `-fdefer-out-of-scope-variables`.	dynamic	`-Wno-deferred-out-of-scope-variables`
`-Wdeferred-type-errors`	Report warnings when deferred type errors are enabled. This option is enabled by default. See `-fdefer-type-errors`.	dynamic	`-Wno-deferred-type-errors`
`-Wdeprecated-flags`	warn about uses of commandline flags that are deprecated	dynamic	`-Wno-deprecated-flags`
`-Wdeprecated-type-abstractions`	warn when type abstractions in constructor patterns are used without enabling `TypeApplications`	dynamic	`-Wno-deprecated-type-abstractions`
`-Wdeprecations`	warn about uses of functions & types that have DEPRECATED pragmas, or WARNING pragmas with the `deprecated` category.	dynamic	`-Wno-deprecations`
`-Wderiving-defaults`	warn about default deriving when using both `DeriveAnyClass` and `GeneralizedNewtypeDeriving`	dynamic	`-Wno-deriving-defaults`
`-Wderiving-typeable`	warn when Typeable is derived	dynamic	`-Wno-deriving-typeable`
`-Wdodgy-exports`	warn about dodgy exports	dynamic	`-Wno-dodgy-exports`
`-Wdodgy-foreign-imports`	warn about dodgy foreign imports	dynamic	`-Wno-dodgy-foreign-imports`
`-Wdodgy-imports`	warn about dodgy imports	dynamic	`-Wno-dodgy-imports`
`-Wduplicate-constraints`	warn when a constraint appears duplicated in a type signature	dynamic	`-Wno-duplicate-constraints`
`-Wduplicate-exports`	warn when an entity is exported multiple times	dynamic	`-Wno-duplicate-exports`
`-Wempty-enumerations`	warn about enumerations that are empty	dynamic	`-Wno-empty-enumerations`
`-Werror`	make warnings fatal	dynamic	`-Wwarn`
`-Weverything`	enable all warnings supported by GHC	dynamic	`-w`
`-Wextended-warnings`	warn about uses of functions & types that have WARNING or DEPRECATED pragmas, across all categories	dynamic	`-Wno-extended-warnings`
`-Wextra`	alias for `-W`	dynamic	`-Wno-extra`
`-Wforall-identifier`	(deprecated) Does nothing	dynamic
`-Wgadt-mono-local-binds`	warn when pattern matching on a GADT without MonoLocalBinds	dynamic	`-Wno-gadt-mono-local-binds`
`-Whi-shadowing`	(deprecated) warn when a `.hi` file in the current directory shadows a library	dynamic	`-Wno-hi-shadowing`
`-Widentities`	warn about uses of Prelude numeric conversions that are probably the identity (and hence could be omitted)	dynamic	`-Wno-identities`
`-Wimplicit-kind-vars`	(deprecated) warn when kind variables are implicitly quantified over.	dynamic	`-Wno-implicit-kind-vars`
`-Wimplicit-lift`	warn about implicit `lift` in Template Haskell quotes	dynamic	`-Wno-implicit-lift`
`-Wimplicit-prelude`	warn when the Prelude is implicitly imported	dynamic	`-Wno-implicit-prelude`
`-Wimplicit-rhs-quantification`	warn when type variables on the RHS of a type synonym are implicitly quantified	dynamic	`-Wno-implicit-rhs-quantification`
`-Winaccessible-code`	warn about inaccessible code	dynamic	`-Wno-inaccessible-code`
`-Wincomplete-export-warnings`	warn when some but not all of exports for a name are warned about	dynamic	`-Wno-incomplete-export-warnings`
`-Wincomplete-patterns`	warn when a pattern match could fail	dynamic	`-Wno-incomplete-patterns`
`-Wincomplete-record-selectors`	warn when a record selector application could fail	dynamic	`-Wno-incomplete-record-selectors`
`-Wincomplete-record-updates`	warn when a record update could fail	dynamic	`-Wno-incomplete-record-updates`
`-Wincomplete-uni-patterns`	warn when a pattern match in a lambda expression, pattern binding or a lazy pattern could fail	dynamic	`-Wno-incomplete-uni-patterns`
`-Winconsistent-flags`	warn when command line options are inconsistent in some way.	dynamic	`-Wno-inconsistent-flags`
`-Winferred-safe-imports`	warn when an explicitly Safe Haskell module imports a Safe-Inferred one	dynamic	`-Wno-inferred-safe-imports`
`-Winline-rule-shadowing`	Warn if a rewrite RULE might fail to fire because the function might be inlined before the rule has a chance to fire. See How rules interact with INLINE/NOINLINE pragmas.	dynamic	`-Wno-inline-rule-shadowing`
`-Winvalid-haddock`	warn when a Haddock comment occurs in an invalid position	dynamic	`-Wno-invalid-haddock`
`-Wloopy-superclass-solve`	(deprecated) warn when creating potentially-loopy superclass constraint evidence	dynamic	`-Wno-loopy-superclass-solve`
`-Wmisplaced-pragmas`	warn about uses of file header pragmas in the module body	dynamic	`-Wno-misplaced-pragmas`
`-Wmissed-extra-shared-lib`	Warn when GHCi can't load a shared lib.	dynamic	`-Wno-missed-extra-shared-lib`
`-Wmissed-specialisations`	warn when specialisation of an imported, overloaded function fails.	dynamic	`-Wno-missed-specialisations`
`-Wmissed-specializations`	alias for `-Wmissed-specialisations`	dynamic	`-Wno-missed-specializations`
`-Wmissing-deriving-strategies`	warn when deriving without mentioning a deriving strategy	dynamic	`-Wno-missing-deriving-strategies`
`-Wmissing-export-lists`	warn when a module declaration does not explicitly list all exports	dynamic	`-Wno-missing-export-lists`
`-Wmissing-exported-pattern-synonym-signatures`	warn about pattern synonyms without signatures, only if they are exported	dynamic	`-Wno-missing-exported-pattern-synonym-signatures`
`-Wmissing-exported-signatures`	warn about top-level functions without signatures, only if they are exported	dynamic	`-Wno-missing-exported-signatures`
`-Wmissing-exported-sigs`	(deprecated) warn about top-level functions without signatures, only if they are exported. takes precedence over -Wmissing-signatures	dynamic	`-Wno-missing-exported-sigs`
`-Wmissing-fields`	warn when fields of a record are uninitialised	dynamic	`-Wno-missing-fields`
`-Wmissing-home-modules`	warn when encountering a home module imported, but not listed on the command line. Useful for cabal to ensure GHC won't pick up modules, not listed neither in `exposed-modules`, nor in `other-modules`.	dynamic	`-Wno-missing-home-modules`
`-Wmissing-import-lists`	warn when an import declaration does not explicitly list all the names brought into scope	dynamic	`-Wno-missing-import-lists`
`-Wmissing-kind-signatures`	warn when type declarations don't have kind signatures nor CUSKs	dynamic	`-Wno-missing-kind-signatures`
`-Wmissing-local-signatures`	warn about polymorphic local bindings without signatures	dynamic	`-Wno-missing-local-signatures`
`-Wmissing-local-sigs`	(deprecated) warn about polymorphic local bindings without signatures	dynamic	`-Wno-missing-local-sigs`
`-Wmissing-methods`	warn when class methods are undefined	dynamic	`-Wno-missing-methods`
`-Wmissing-monadfail-instances`	(deprecated) Warn when a failable pattern is used in a do-block that does not have a `MonadFail` instance.	dynamic	`-Wno-missing-monadfail-instances`
`-Wmissing-pattern-synonym-signatures`	warn when pattern synonyms do not have type signatures	dynamic	`-Wno-missing-pattern-synonym-signatures`
`-Wmissing-poly-kind-signatures`	warn when inferred polykinded type or class declaration don't have kind signatures nor CUSKs	dynamic	`-Wno-missing-poly-kind-signatures`
`-Wmissing-role-annotations`	warn when type declarations don't have role annotations	dynamic	`-Wno-role-annotations-signatures`
`-Wmissing-safe-haskell-mode`	warn when the Safe Haskell mode is not explicitly specified.	dynamic	`-Wno-missing-safe-haskell-mode`
`-Wmissing-signatures`	warn about top-level functions without signatures	dynamic	`-Wno-missing-signatures`
`-Wmissing-space-after-bang`	(deprecated) Does nothing	dynamic
`-Wmonomorphism-restriction`	warn when the Monomorphism Restriction is applied	dynamic	`-Wno-monomorphism-restriction`
`-Wname-shadowing`	warn when names are shadowed	dynamic	`-Wno-name-shadowing`
`-Wnoncanonical-monad-instances`	warn when `Applicative` or `Monad` instances have noncanonical definitions of `return`, `pure`, `(>>)`, or `(*>)`. See flag description in Warnings and sanity-checking for more details.	dynamic	`-Wno-noncanonical-monad-instances`
`-Wnoncanonical-monadfail-instances`	(deprecated) warn when `Monad` or `MonadFail` instances have noncanonical definitions of `fail`.	dynamic	`-Wno-noncanonical-monadfail-instances`
`-Wnoncanonical-monoid-instances`	warn when `Semigroup` or `Monoid` instances have noncanonical definitions of `(<>)` or `mappend`. See flag description in Warnings and sanity-checking for more details.	dynamic	`-Wno-noncanonical-monoid-instances`
`-Wnot`	(deprecated) Alias for `-w`	dynamic
`-Woperator-whitespace`	warn on prefix, suffix, and tight infix uses of infix operators	dynamic	`-Wno-operator-whitespace`
`-Woperator-whitespace-ext-conflict`	warn on uses of infix operators that would be parsed differently were a particular GHC extension enabled	dynamic	`-Wno-operator-whitespace-ext-conflict`
`-Worphans`	warn when the module contains orphan instance declarations or rewrite rules	dynamic	`-Wno-orphans`
`-Woverflowed-literals`	warn about literals that will overflow their type	dynamic	`-Wno-overflowed-literals`
`-Woverlapping-patterns`	warn about overlapping patterns	dynamic	`-Wno-overlapping-patterns`
`-Wpartial-fields`	warn when defining a partial record field.	dynamic	`-Wno-partial-fields`
`-Wpartial-type-signatures`	warn about holes in partial type signatures when `PartialTypeSignatures` is enabled. Not applicable when `PartialTypeSignatures` is not enabled, in which case errors are generated for such holes.	dynamic	`-Wno-partial-type-signatures`
`-Wprepositive-qualified-module`	Report imports with a leading/prepositive "qualified"	dynamic	`-Wno-prepositive-qualified-module`
`-Wredundant-bang-patterns`	Warn about redundant bang patterns.	dynamic	`-Wno-redundant-bang-patterns`
`-Wredundant-constraints`	Have the compiler warn about redundant constraints in type signatures.	dynamic	`-Wno-redundant-constraints`
`-Wredundant-record-wildcards`	Warn about record wildcard matches when the wildcard binds no patterns.	dynamic	`-Wno-redundant-record-wildcards`
`-Wredundant-strictness-flags`	Warn about redundant strictness flags.	dynamic	`-Wno-redundant-strictness-flags`
`-Wsafe`	warn if the module being compiled is regarded to be safe.	dynamic	`-Wno-safe`
`-Wsemigroup`	(deprecated) Warn when a `Monoid` is not `Semigroup`, and on non-`Semigroup` definitions of `(<>)`	dynamic	`-Wno-semigroup`
`-Wsimplifiable-class-constraints`	Warn about class constraints in a type signature that can be simplified using a top-level instance declaration.	dynamic	`-Wno-simplifiable-class-constraints`
`-Wstar-binder`	warn about binding the `(*)` type operator despite `StarIsType`	dynamic	`-Wno-star-binder`
`-Wstar-is-type`	warn when `*` is used to mean `Data.Kind.Type`	dynamic	`-Wno-star-is-type`
`-Wtabs`	warn if there are tabs in the source file	dynamic	`-Wno-tabs`
`-Wterm-variable-capture`	warn when an implicitly quantified type variable captures a term's name	dynamic
`-Wtrustworthy-safe`	warn if the module being compiled is marked as `Trustworthy` but it could instead be marked as `Safe`, a more informative bound.	dynamic	`-Wno-safe`
`-Wtype-defaults`	warn when defaulting happens	dynamic	`-Wno-type-defaults`
`-Wtype-equality-out-of-scope`	warn when type equality `a ~ b` is used despite being out of scope	dynamic	`-Wno-type-equality-out-of-scope`
`-Wtype-equality-requires-operators`	warn when type equality `a ~ b` is used despite being out of scope	dynamic	`-Wno-type-equality-requires-operators`
`-Wtyped-holes`	Report warnings when typed hole errors are deferred until runtime. See `-fdefer-typed-holes`.	dynamic	`-Wno-typed-holes`
`-Wunbanged-strict-patterns`	warn on pattern bind of unlifted variable that is neither bare nor banged	dynamic	`-Wno-unbanged-strict-patterns`
`-Wunicode-bidirectional-format-characters`	warn about the usage of unicode bidirectional layout override characters	dynamic
`-Wunrecognised-pragmas`	warn about uses of pragmas that GHC doesn't recognise	dynamic	`-Wno-unrecognised-pragmas`
`-Wunrecognised-warning-flags`	throw a warning when an unrecognised `-W...` flag is encountered on the command line.	dynamic	`-Wno-unrecognised-warning-flags`
`-Wunsafe`	warn if the module being compiled is regarded to be unsafe. See Safe Haskell	dynamic	`-Wno-unsafe`
`-Wunsupported-calling-conventions`	warn about use of an unsupported calling convention	dynamic	`-Wno-unsupported-calling-conventions`
`-Wunsupported-llvm-version`	Warn when using `-fllvm` with an unsupported version of LLVM.	dynamic	`-Wno-unsupported-llvm-version`
`-Wunticked-promoted-constructors`	warn if promoted constructors are not ticked	dynamic	`-Wno-unticked-promoted-constructors`
`-Wunused-binds`	warn about bindings that are unused. Alias for `-Wunused-top-binds`, `-Wunused-local-binds` and `-Wunused-pattern-binds`	dynamic	`-Wno-unused-binds`
`-Wunused-do-bind`	warn about do bindings that appear to throw away values of types other than `()`	dynamic	`-Wno-unused-do-bind`
`-Wunused-foralls`	warn about type variables in user-written `forall`\s that are unused	dynamic	`-Wno-unused-foralls`
`-Wunused-imports`	warn about unnecessary imports	dynamic	`-Wno-unused-imports`
`-Wunused-local-binds`	warn about local bindings that are unused	dynamic	`-Wno-unused-local-binds`
`-Wunused-matches`	warn about variables in patterns that aren't used	dynamic	`-Wno-unused-matches`
`-Wunused-packages`	warn when package is requested on command line, but not needed.	dynamic	`-Wno-unused-packages`
`-Wunused-pattern-binds`	warn about pattern match bindings that are unused	dynamic	`-Wno-unused-pattern-binds`
`-Wunused-record-wildcards`	Warn about record wildcard matches when none of the bound variables are used.	dynamic	`-Wno-unused-record-wildcards`
`-Wunused-top-binds`	warn about top-level bindings that are unused	dynamic	`-Wno-unused-top-binds`
`-Wunused-type-patterns`	warn about unused type variables which arise from patterns in in type family and data family instances	dynamic	`-Wno-unused-type-patterns`
`-Wview-pattern-signatures`	warn when a view pattern is used with type signature without explicit parens	dynamic	`-Wno-view-pattern-signatures`
`-Wwarn`	make warnings non-fatal	dynamic	`-Werror`
`-Wwarnings-deprecations`	warn about uses of functions & types that have DEPRECATED pragmas, or WARNING pragmas with the `deprecated` category. Alias for `-Wdeprecations`.	dynamic	`-Wno-warnings-deprecations`
`-Wwrong-do-bind`	warn about do bindings that appear to throw away monadic values that you should have bound instead	dynamic	`-Wno-wrong-do-bind`
`-Wx-⟨category⟩`	warn about uses of functions & types that have WARNING pragmas with the given category	dynamic	`-Wno-x-⟨category⟩`

5.6.15. Optimisation levels¶

These options are described in more detail in Optimisation (code improvement).

See Individual optimisations for a list of optimisations enabled on level 1 and level 2.

Flag	Description	Type	Reverse
`-O`, `-O1`	Enable level 1 optimisations	dynamic	`-O0`
`-O0`	Disable optimisations (default)	dynamic
`-O2`	Enable level 2 optimisations	dynamic	`-O0`
`-O⟨n⟩`	Any -On where n > 2 is the same as -O2.	dynamic	`-O0`

5.6.16. Individual optimisations¶

These options are described in more detail in -f*: platform-independent flags. If a flag is implied by -O then it is also implied by -O2 (unless flag description explicitly says otherwise). If a flag is implied by -O0 only then the flag is not implied by -O and -O2.

Flag	Description	Type	Reverse
`-fasm-shortcutting`	Enable shortcutting on assembly. Implied by `-O2`.	dynamic	`-fno-asm-shortcutting`
`-fbinary-blob-threshold=⟨n⟩`	default: 500K. Tweak assembly generator for binary blobs.	dynamic
`-fblock-layout-cfg`	Use the new cfg based block layout algorithm. Implied by `-O`.	dynamic	`-fno-block-layout-cfg`
`-fblock-layout-weightless`	Ignore cfg weights for code layout.	dynamic	`-fno-block-layout-weightless`
`-fblock-layout-weights`	Sets edge weights used by the new code layout algorithm.	dynamic
`-fcall-arity`	Enable call-arity optimisation. Implied by `-O`.	dynamic	`-fno-call-arity`
`-fcase-folding`	Enable constant folding in case expressions. Implied by `-O`.	dynamic	`-fno-case-folding`
`-fcase-merge`	Enable case-merging. Implied by `-O`.	dynamic	`-fno-case-merge`
`-fcmm-control-flow`	Enable control flow optimisation in the Cmm backend. Implied by `-O`.	dynamic	`-fno-cmm-control-flow`
`-fcmm-elim-common-blocks`	Enable Cmm common block elimination. Implied by `-O`.	dynamic	`-fno-cmm-elim-common-blocks`
`-fcmm-sink`	Enable Cmm sinking. Implied by `-O`.	dynamic	`-fno-cmm-sink`
`-fcmm-static-pred`	Enable static control flow prediction. Implied by `-O`.	dynamic	`-fno-cmm-static-pred`
`-fcore-constant-folding`	Enable constant folding in Core. Implied by `-O`.	dynamic	`-fno-core-constant-folding`
`-fcpr-anal`	Turn on Constructed Product Result analysis. Implied by `-O`.	dynamic	`-fno-cpr-anal`
`-fcross-module-specialise`	Turn on specialisation of overloaded functions imported from other modules. Implied by `-O`.	dynamic	`-fno-cross-module-specialise`
`-fcse`	Enable common sub-expression elimination. Implied by `-O`.	dynamic	`-fno-cse`
`-fdicts-cheap`	Make dictionary-valued expressions seem cheap to the optimiser.	dynamic	`-fno-dicts-cheap`
`-fdicts-strict`	Make dictionaries strict. Implied by `-O2`.	dynamic	`-fno-dicts-strict`
`-fdmd-tx-dict-sel`	(deprecated) Use a special demand transformer for dictionary selectors.	dynamic	`-fno-dmd-tx-dict-sel`
`-fdmd-unbox-width=⟨n⟩`	default: 3. Boxity analysis pretends that returned records with this many fields can be unboxed.	dynamic
`-fdo-clever-arg-eta-expansion`	Enable sophisticated argument eta-expansion. Implied by `-O2`.	dynamic	`-fno-do-clever-arg-eta-expansion`
`-fdo-eta-reduction`	Enable eta-reduction. Always enabled by default.	dynamic	`-fno-do-eta-reduction`
`-fdo-lambda-eta-expansion`	Enable lambda eta-expansion. Always enabled by default.	dynamic	`-fno-do-lambda-eta-expansion`
`-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	`-fno-enable-rewrite-rules`
`-fexcess-precision`	Enable excess intermediate precision	dynamic	`-fno-excess-precision`
`-fexitification`	Enables exitification optimisation. Implied by `-O`.	dynamic	`-fno-exitification`
`-fexpose-all-unfoldings`	Expose all unfoldings, even for very large or recursive functions.	dynamic	`-fno-expose-all-unfoldings`
`-fexpose-overloaded-unfoldings`	Expose unfoldings carrying constraints, even for very large or recursive functions.	dynamic	`-fno-expose-overloaded-unfoldings`
`-ffloat-in`	Turn on the float-in transformation. Implied by `-O`.	dynamic	`-fno-float-in`
`-ffull-laziness`	Turn on full laziness (floating bindings outwards). Implied by `-O`.	dynamic	`-fno-full-laziness`
`-ffun-to-thunk`	(deprecated) superseded by -ffull-laziness.	dynamic	`-fno-fun-to-thunk`
`-fignore-asserts`	Ignore assertions in the source. Implied by `-O`.	dynamic	`-fno-ignore-asserts`
`-fignore-interface-pragmas`	Ignore pragmas in interface files. Implied by `-O0` only.	dynamic	`-fno-ignore-interface-pragmas`
`-finline-generics`	Annotate methods of derived Generic and Generic1 instances with INLINE[1] pragmas based on heuristics. Implied by `-O`.	dynamic	`-fno-inline-generics`
`-finline-generics-aggressively`	Annotate methods of all derived Generic and Generic1 instances with INLINE[1] pragmas.	dynamic	`-fno-inline-generics-aggressively`
`-fkeep-auto-rules`	Keep all "auto" rules, generated by specialisation	dynamic	`-fno-keep-auto-rules`
`-flate-dmd-anal`	Run demand analysis again, at the end of the simplification pipeline	dynamic	`-fno-late-dmd-anal`
`-flate-specialise`	Run a late specialisation pass	dynamic	`-fno-late-specialise`
`-fliberate-case`	Turn on the liberate-case transformation. Implied by `-O2`.	dynamic	`-fno-liberate-case`
`-fliberate-case-threshold=⟨n⟩`	default: 2000. Set the size threshold for the liberate-case transformation to ⟨n⟩	dynamic	`-fno-liberate-case-threshold`
`-fllvm-pass-vectors-in-regs`	(deprecated) Does nothing	dynamic
`-flocal-float-out`	Enable local floating definitions out of let-binds.	dynamic	`-fno-local-float-out`
`-flocal-float-out-top-level`	Enable local floating to float top-level bindings	dynamic	`-fno-local-float-out-top-level`
`-floopification`	Turn saturated self-recursive tail-calls into local jumps in the generated assembly. Implied by `-O`.	dynamic	`-fno-loopification`
`-fmax-forced-spec-args=⟨n⟩`	default: 333. Maximum number of value arguments for forced SpecConstr specializations.	dynamic
`-fmax-inline-alloc-size=⟨n⟩`	default: 128. Set the maximum size of inline array allocations to ⟨n⟩ bytes (default: 128).	dynamic
`-fmax-inline-memcpy-insns=⟨n⟩`	default: 32. Inline `memcpy` calls if they would generate no more than ⟨n⟩ pseudo instructions.	dynamic
`-fmax-inline-memset-insns=⟨n⟩`	default: 32. Inline `memset` calls if they would generate no more than ⟨n⟩ pseudo instructions	dynamic
`-fmax-simplifier-iterations=⟨n⟩`	default: 4. Set the max iterations for the simplifier.	dynamic
`-fmax-uncovered-patterns=⟨n⟩`	default: 4. Set the maximum number of patterns to display in warnings about non-exhaustive ones.	dynamic
`-fmax-worker-args=⟨n⟩`	default: 10. Maximum number of value arguments for a worker.	dynamic
`-fno-opt-coercion`	Turn off the coercion optimiser	dynamic
`-fno-pre-inlining`	Turn off pre-inlining	dynamic
`-fno-state-hack`	Turn off the state hackwhereby any lambda with a real-world state token as argument is considered to be single-entry. Hence OK to inline things inside it.	dynamic
`-fobject-determinism`	Produce fully deterministic object code	dynamic	`-fno-object-determinism`
`-fomit-interface-pragmas`	Don't generate interface pragmas. Implied by `-O0` only.	dynamic	`-fno-omit-interface-pragmas`
`-fomit-yields`	Omit heap checks when no allocation is being performed.	dynamic	`-fno-omit-yields`
`-foptimal-applicative-do`	Use a slower but better algorithm for ApplicativeDo	dynamic	`-fno-optimal-applicative-do`
`-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	`-fno-pedantic-bottoms`
`-fpolymorphic-specialisation`	Allow specialisation to abstract over free type variables	dynamic	`-fno-polymorphic-specialisation`
`-fregs-graph`	Use the graph colouring register allocator for register allocation in the native code generator.	dynamic	`-fno-regs-graph`
`-fregs-iterative`	Use the iterative coalescing graph colouring register allocator in the native code generator.	dynamic	`-fno-regs-iterative`
`-fsimpl-tick-factor=⟨n⟩`	default: 100. Set the percentage factor for simplifier ticks.	dynamic
`-fsimplifier-phases=⟨n⟩`	default: 2. Set the number of phases for the simplifier. Ignored with `-O0`.	dynamic
`-fsolve-constant-dicts`	When solving constraints, try to eagerly solve super classes using available dictionaries. Implied by `-O`.	dynamic	`-fno-solve-constant-dicts`
`-fspec-constr`	Turn on the SpecConstr transformation. Implied by `-O2`.	dynamic	`-fno-spec-constr`
`-fspec-constr-count=⟨n⟩`	default: 3.* Set to ⟨n⟩ the maximum number of specialisations that will be created for any one function by the SpecConstr transformation.	dynamic	`-fno-spec-constr-count`
`-fspec-constr-keen`	Specialize a call with an explicit constructor argument, even if the argument is not scrutinised in the body of the function	dynamic	`-fno-spec-constr-keen`
`-fspec-constr-threshold=⟨n⟩`	default: 2000. Set the size threshold for the SpecConstr transformation to ⟨n⟩.	dynamic	`-fno-spec-constr-threshold`
`-fspecialise`	Turn on specialisation of overloaded functions. Implied by `-O`.	dynamic	`-fno-specialise`
`-fspecialise-aggressively`	Turn on specialisation of overloaded functions regardless of size, if unfolding is available	dynamic	`-fno-specialise-aggressively`
`-fspecialise-incoherents`	Enable specialisation on incoherent instances	dynamic	`-fno-specialise-incoherents`
`-fstatic-argument-transformation`	Turn on the static argument transformation.	dynamic	`-fno-static-argument-transformation`
`-fstg-cse`	Enable common sub-expression elimination on the STG intermediate language. Implied by `-O`.	dynamic	`-fno-stg-cse`
`-fstg-lift-lams`	Enable late lambda lifting on the STG intermediate language. Implied by `-O2`.	dynamic	`-fno-stg-lift-lams`
`-fstg-lift-lams-known`	Allow turning known into unknown calls while performing late lambda lifting.	dynamic	`-fno-stg-lift-lams-known`
`-fstg-lift-lams-non-rec-args`	Create top-level non-recursive functions with at most <n> parameters while performing late lambda lifting.	dynamic	`-fstg-lift-lams-non-rec-args-any`
`-fstg-lift-lams-rec-args`	Create top-level recursive functions with at most <n> parameters while performing late lambda lifting.	dynamic	`-fstg-lift-lams-rec-args-any`
`-fstrictness`	Turn on demand analysis. Implied by `-O`. Implies `-fworker-wrapper`	dynamic	`-fno-strictness`
`-fstrictness-before=⟨n⟩`	Run an additional demand analysis before simplifier phase ⟨n⟩	dynamic
`-funbox-small-strict-fields`	Flatten strict constructor fields with a pointer-sized representation. Implied by `-O`.	dynamic	`-fno-unbox-small-strict-fields`
`-funbox-strict-fields`	Flatten strict constructor fields	dynamic	`-fno-unbox-strict-fields`
`-funfolding-case-scaling=⟨n⟩`	default: 30. Apply a penalty of (inlining_cost * 1/n) for each level of case nesting.	dynamic
`-funfolding-case-threshold=⟨n⟩`	default: 2. Reduce inlining for cases nested deeper than n.	dynamic
`-funfolding-creation-threshold=⟨n⟩`	default: 750. Tweak unfolding settings.	dynamic
`-funfolding-dict-discount=⟨n⟩`	default: 30. Tweak unfolding settings.	dynamic
`-funfolding-fun-discount=⟨n⟩`	default: 60. Tweak unfolding settings.	dynamic
`-funfolding-keeness-factor=⟨n⟩`	This has been deprecated in GHC 9.0.1.	dynamic
`-funfolding-use-threshold=⟨n⟩`	default: 90. Tweak unfolding settings.	dynamic
`-fworker-wrapper`	Enable the worker/wrapper transformation. Implied by `-O` and by `-fstrictness`.	dynamic
`-fworker-wrapper-cbv`	Enable w/w splits for wrappers whos sole purpose is evaluating arguments.	dynamic
`-fwrite-if-compression=⟨n⟩`	default: 2. Tweak the level of interface file compression.	dynamic

5.6.17. Profiling options¶

More details in Profiling

Flag	Description	Type	Reverse
`-auto`	(deprecated) Alias for `-fprof-auto-exported`	dynamic
`-auto-all`	(deprecated) Alias for `-fprof-auto`	dynamic
`-caf-all`	(deprecated) Alias for `-fprof-cafs`	dynamic
`-fno-prof-count-entries`	Do not collect entry counts	dynamic	`-fprof-count-entries`
`-fprof-auto`	Auto-add `SCC`\ s to all bindings not marked INLINE	dynamic	`-fno-prof-auto`
`-fprof-auto-calls`	Auto-add `SCC`\ s to all call sites	dynamic	`-fno-prof-auto`
`-fprof-auto-exported`	Auto-add `SCC`\ s to all exported bindings not marked `INLINE`	dynamic	`-fno-prof-auto`
`-fprof-auto-top`	Auto-add `SCC`\ s to all top-level bindings not marked INLINE	dynamic	`-fno-prof-auto`
`-fprof-cafs`	Auto-add `SCC`\ s to all CAFs	dynamic	`-fno-prof-cafs`
`-fprof-callers=⟨name⟩`	Auto-add `SCC`\ s to all call-sites of the named function.	dynamic
`-fprof-late`	Auto-add `SCC`\ s to all top level bindings after the core pipeline has run.	dynamic	`-fno-prof-late`
`-fprof-late-inline`	Auto-add `SCC`\ s to all top level bindings after the optimizer has run and retain them when inlining.	dynamic	`-fno-prof-late-inline`
`-fprof-late-overloaded`	Auto-add `SCC`\ s to all top level overloaded bindings after the core pipeline has run.	dynamic	`-fno-prof-late-overloaded`
`-fprof-late-overloaded-calls`	Auto-add `SCC`\ s to all call sites that include dictionary arguments after the core pipeline has run.	dynamic	`-fno-prof-late-overloaded-calls`
`-fprof-manual`	Process manual `SCC` annotations.	dynamic	`-fno-prof-manual`
`-no-auto`	(deprecated) Alias for `-fno-prof-auto`	dynamic
`-no-auto-all`	(deprecated) Alias for `-fno-prof-auto`	dynamic
`-no-caf-all`	(deprecated) Alias for `-fno-prof-cafs`	dynamic
`-prof`	Turn on profiling	dynamic
`-ticky`	Turn on ticky-ticky profiling	dynamic
`-ticky-allocd`	Track the number of times each closure type is allocated.	dynamic
`-ticky-ap-thunk`	Don't use standard AP thunks on order to get more reliable entry counters.	dynamic
`-ticky-dyn-thunk`	Track allocations of dynamic thunks	dynamic
`-ticky-LNE`	Treat join point binders similar to thunks/functions.	dynamic
`-ticky-tag-checks`	Emit dummy ticky counters to record how many tag-inference checks tag inference avoided.	dynamic

5.6.18. Program coverage options¶

More details in Observing Code Coverage

Flag Description Type Reverse

-fhpc

Turn on Haskell program coverage instrumentation

dynamic

-hpcdir⟨dir⟩

Set the directory where GHC places .mix files.

dynamic

5.6.19. C pre-processor options¶

More details in Options affecting the C pre-processor

Flag	Description	Type	Reverse
`-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⟩`
`-I⟨dir⟩`	Add ⟨dir⟩ to the directory search list for `#include` files	dynamic
`-U⟨symbol⟩`	Undefine a symbol in the C pre-processor	dynamic

5.6.20. Code generation options¶

More details in Options affecting code generation

Flag	Description	Type	Reverse
`-dynamic-too`	Build dynamic object files as well as static object files during compilation	dynamic
`-fasm`	Use the native code generator	dynamic	`-fllvm`
`-fbyte-code`	Generate byte-code	dynamic
`-fbyte-code-and-object-code`	Generate object code and byte-code	dynamic
`-fexpose-internal-symbols`	Produce symbols for all functions, including internal functions.	dynamic
`-fexternal-dynamic-refs`	Generate code for linking against dynamic libraries	dynamic
`-fllvm`	Compile using the LLVM code generator	dynamic	`-fasm`
`-fno-code`	Omit code generation	dynamic
`-fobject-code`	Generate object code	dynamic
`-fPIC`	Generate position-independent code (where available)	dynamic
`-fPIE`	Generate code for a position-independent executable (where available)	dynamic
`-fprefer-byte-code`	Use byte-code if it is available to evaluate TH splices	dynamic
`-fwrite-if-simplified-core`	Write an interface file containing the simplified core of the module.	dynamic
`-fwrite-interface`	Always write interface files	dynamic

5.6.21. Linking options¶

More details in Options affecting linking

Flag	Description	Type	Reverse
`-c`	Stop after generating object (`.o`) file	mode
`-debug`	Use the debugging runtime	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/OS X only)	dynamic
`-dynamic`	Build dynamically-linked object files and executables	dynamic
`-dynload`	Selects one of a number of modes for finding shared libraries at runtime.	dynamic
`-eventlog`	Enable runtime event tracing	dynamic
`-fcompact-unwind`	Instruct the linker to produce a __compact_unwind section.	dynamic
`-fkeep-cafs`	Do not garbage-collect CAFs (top-level expressions) at runtime	dynamic
`-flink-rts`	Link the runtime when generating a shared or static library	dynamic
`-fno-embed-manifest`	Do not embed the manifest in the executable (Windows only)	dynamic
`-fno-gen-manifest`	Do not generate a manifest file (Windows only)	dynamic
`-fno-shared-implib`	Don't generate an import library for a DLL (Windows only)	dynamic
`-framework ⟨name⟩`	On Darwin/OS X/iOS only, link in the framework ⟨name⟩. This option corresponds to the `-framework` option for Apple's Linker.	dynamic
`-framework-path ⟨dir⟩`	On Darwin/OS X/iOS only, add ⟨dir⟩ to the list of directories searched for frameworks. This option corresponds to the `-F` option for Apple's Linker.	dynamic
`-fsplit-sections`, `-split-sections`	Split sections for link-time dead-code stripping	dynamic	`-fno-split-sections`
`-fuse-rpaths`	Set the rpath based on -L flags	dynamic
`-fwhole-archive-hs-libs`	When linking a binary executable, this inserts the flag `-Wl,--whole-archive` before any `-l` flags for Haskell libraries, and `-Wl,--no-whole-archive` afterwards	dynamic
`-L ⟨dir⟩`	Add ⟨dir⟩ to the list of directories searched for libraries	dynamic
`-l ⟨lib⟩`	Link in library ⟨lib⟩	dynamic
`-main-is ⟨thing⟩`	Set main module and function	dynamic
`-no-hs-main`	Don't assume this program contains `main`	dynamic
`-no-pie`	Don't instruct the linker to produce a position-independent executable.	dynamic	`-pie`
`-no-rtsopts-suggestions`	Don't print RTS suggestions about linking with `-rtsopts[=⟨none\|some\|all\|ignore\|ignoreAll⟩]`.	dynamic
`-package ⟨name⟩`	Expose package ⟨pkg⟩	dynamic
`-pie`	Instruct the linker to produce a position-independent executable.	dynamic	`-no-pie`
`-rdynamic`	This instructs the linker to add all symbols, not only used ones, to the dynamic symbol table. Currently Linux and Windows/MinGW32 only. This is equivalent to using `-optl -rdynamic` on Linux, and `-optl -export-all-symbols` on Windows.	dynamic
`-rtsopts[=⟨none\|some\|all\|ignore\|ignoreAll⟩]`	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, if `-rtsopts` is not passed); `all` means that all RTS flags are permitted (the default, if `-rtsopts` is passed with no argument); `ignore` means RTS flags can be given, but are treated as regular arguments and passed to the Haskell program as arguments; `ignoreAll` is the same as `ignore`, but `GHCRTS` is also ignored. `-rtsopts` does not affect `-with-rtsopts` behavior; flags passed via `-with-rtsopts` are used regardless of `-rtsopts`.	dynamic
`-shared`	Generate a shared library (as opposed to an executable)	dynamic
`-single-threaded`	Use the single-threaded runtime	dynamic	`-threaded`
`-static`	Use static Haskell libraries	dynamic
`-staticlib`	Generate a standalone static library (as opposed to an executable). This is useful when cross compiling. The library together with all its dependencies ends up in in a single static library that can be linked against.	dynamic
`-threaded`	Use the threaded runtime	dynamic	`-single-threaded`
`-with-rtsopts=⟨opts⟩`	Set the default RTS options to ⟨opts⟩.	dynamic

5.6.22. Plugin options¶

More details in Compiler Plugins

Flag	Description	Type
`-fclear-plugins`	Clear the list of active plugins	dynamic
`-fplugin-library=⟨file-path⟩;⟨unit-id⟩;⟨module⟩;⟨args⟩`	Load a pre-compiled static plugin from an external library	dynamic
`-fplugin-opt=⟨module⟩:⟨args⟩`	Give arguments to a plugin module; module must be specified with `-fplugin=⟨module⟩`	dynamic
`-fplugin-trustworthy`	Trust the used plugins and no longer mark the compiled module as unsafe	dynamic
`-fplugin=⟨module⟩`	Load a plugin exported by a given module	dynamic
`-hide-all-plugin-packages`	Hide all packages for plugins by default	dynamic
`-plugin-package ⟨pkg⟩`	Expose ⟨pkg⟩ for plugins	dynamic
`-plugin-package-id ⟨pkg-id⟩`	Expose ⟨pkg-id⟩ for plugins	dynamic

5.6.23. Replacing phases¶

More details in Replacing the program for one or more phases

Flag	Description	Type
`-pgma ⟨cmd⟩`	Use ⟨cmd⟩ as the assembler	dynamic
`-pgmc ⟨cmd⟩`	Use ⟨cmd⟩ as the C compiler	dynamic
`-pgmCmmP ⟨cmd⟩`	Use ⟨cmd⟩ as the C-- C pre-processor	dynamic
`-pgmcxx ⟨cmd⟩`	Use ⟨cmd⟩ as the C++ compiler	dynamic
`-pgmF ⟨cmd⟩`	Use ⟨cmd⟩ as the pre-processor (with `-F` only)	dynamic
`-pgmi ⟨cmd⟩`	Use ⟨cmd⟩ as the external interpreter command.	dynamic
`-pgminstall_name_tool ⟨cmd⟩`	Use ⟨cmd⟩ as the program to inject `runpath` into mach-o dylibs on macOS	dynamic
`-pgmJSP ⟨cmd⟩`	Use ⟨cmd⟩ as the JavaScript C pre-processor (only for javascript-backend)	dynamic
`-pgmL ⟨cmd⟩`	Use ⟨cmd⟩ as the literate pre-processor	dynamic
`-pgml ⟨cmd⟩`	Use ⟨cmd⟩ as the linker	dynamic
`-pgmlas ⟨cmd⟩`	Use ⟨cmd⟩ as the LLVM assembler	dynamic
`-pgmlc ⟨cmd⟩`	Use ⟨cmd⟩ as the LLVM compiler	dynamic
`-pgmlm ⟨cmd⟩`	Use ⟨cmd⟩ as the linker when merging object files	dynamic
`-pgmlo ⟨cmd⟩`	Use ⟨cmd⟩ as the LLVM optimiser	dynamic
`-pgmotool ⟨cmd⟩`	Use ⟨cmd⟩ as the program to inspect mach-o dylibs on macOS	dynamic
`-pgmP ⟨cmd⟩`	Use ⟨cmd⟩ as the C pre-processor (with `-cpp` only)	dynamic
`-pgms ⟨cmd⟩`	Use ⟨cmd⟩ as the splitter	dynamic
`-pgmwindres ⟨cmd⟩`	Use ⟨cmd⟩ as the program for embedding manifests on Windows.	dynamic

5.6.24. Forcing options to particular phases¶

More details in Forcing options to a particular phase

Flag	Description	Type
`-opta ⟨option⟩`	pass ⟨option⟩ to the assembler	dynamic
`-optc ⟨option⟩`	pass ⟨option⟩ to the C compiler	dynamic
`-optCmmP ⟨option⟩`	pass ⟨option⟩ to the C-- C pre-processor.	dynamic
`-optcxx ⟨option⟩`	pass ⟨option⟩ to the C++ compiler	dynamic
`-optF ⟨option⟩`	pass ⟨option⟩ to the custom pre-processor	dynamic
`-opti ⟨option⟩`	pass ⟨option⟩ to the interpreter sub-process.	dynamic
`-optJSP ⟨option⟩`	pass ⟨option⟩ to JavaScript C pre-processor (only for javascript-backend)	dynamic
`-optL ⟨option⟩`	pass ⟨option⟩ to the literate pre-processor	dynamic
`-optl ⟨option⟩`	pass ⟨option⟩ to the linker	dynamic
`-optlas ⟨option⟩`	pass ⟨option⟩ to the LLVM assembler	dynamic
`-optlc ⟨option⟩`	pass ⟨option⟩ to the LLVM compiler	dynamic
`-optlm ⟨option⟩`	pass ⟨option⟩ to the linker when merging object files.	dynamic
`-optlo ⟨option⟩`	pass ⟨option⟩ to the LLVM optimiser	dynamic
`-optP ⟨option⟩`	pass ⟨option⟩ to cpp (with `-cpp` only)	dynamic
`-optwindres ⟨option⟩`	pass ⟨option⟩ to `windres`.	dynamic
`-pgmc-supports-no-pie`	(deprecated) Indicate that the linker supports `-no-pie`	dynamic
`-pgml-supports-no-pie`	Indicate that the linker supports `-no-pie`	dynamic

5.6.25. Platform-specific options¶

More details in Platform-specific Flags

Flag	Description	Type
`-mavx`	(x86 only) Enable support for AVX SIMD extensions	dynamic
`-mavx2`	(x86 only) Enable support for AVX2 SIMD extensions	dynamic
`-mavx512cd`	(x86 only) Enable support for AVX512-CD SIMD extensions	dynamic
`-mavx512er`	(x86 only) Enable support for AVX512-ER SIMD extensions	dynamic
`-mavx512f`	(x86 only) Enable support for AVX512-F SIMD extensions	dynamic
`-mavx512pf`	(x86 only) Enable support for AVX512-PF SIMD extensions	dynamic
`-mbmi`	(x86 only) Use BMI1 for bit manipulation operations	dynamic
`-mbmi2`	(x86 only) Use BMI2 for bit manipulation operations	dynamic
`-mfma`	Use native FMA instructions for fused multiply-add floating-point operations	dynamic
`-msse`	(x86 only) Use SSE for floating-point operations	dynamic
`-msse2`	(x86 only) Use SSE2 for floating-point operations	dynamic
`-msse3`	(x86 only) Use SSE3 for floating-point operations	dynamic
`-msse4`	(x86 only) Use SSE4 for floating-point operations	dynamic
`-msse4.2`	(x86 only) Use SSE4.2 for floating-point operations	dynamic

5.6.26. Compiler debugging options¶

More details in Debugging the compiler

Flag	Description	Type	Reverse
`-dasm-lint`	ASM pass sanity checking	dynamic
`-dcmm-lint`	C-\- pass sanity checking	dynamic
`-dcore-lint`	Turn on internal sanity checking	dynamic
`-ddisable-js-c-sources`	Disable the link with C sources compiled to JavaScript	dynamic
`-ddisable-js-minifier`	Generate pretty-printed JavaScript code instead of minified (compacted) code.	dynamic
`-ddump-asm`	Dump final assembly	dynamic
`-ddump-asm-conflicts`	Dump register conflicts from the register allocator.	dynamic
`-ddump-asm-liveness`	Dump assembly augmented with register liveness	dynamic
`-ddump-asm-native`	Dump initial assembly	dynamic
`-ddump-asm-regalloc`	Dump the result of register allocation	dynamic
`-ddump-asm-regalloc-stages`	Dump the build/spill stages of the `-fregs-graph` register allocator.	dynamic
`-ddump-asm-stats`	Dump statistics from the register allocator.	dynamic
`-ddump-bcos`	Dump interpreter byte code	dynamic
`-ddump-c-backend`	Dump C code produced by the C (unregisterised) backend.	dynamic
`-ddump-call-arity`	Dump output of the call arity analysis pass.	dynamic
`-ddump-cfg-weights`	Dump the assumed weights of the CFG.	dynamic
`-ddump-cmm`	Dump the final C-\- output	dynamic
`-ddump-cmm-caf`	Dump the results of the C-\- CAF analysis pass.	dynamic
`-ddump-cmm-cbe`	Dump the results of common block elimination	dynamic
`-ddump-cmm-cfg`	Dump the results of the C-\- control flow optimisation pass.	dynamic
`-ddump-cmm-cps`	Dump the results of the CPS pass	dynamic
`-ddump-cmm-from-stg`	Dump STG-to-C-\- output	dynamic
`-ddump-cmm-info`	Dump the results of the C-\- info table augmentation pass.	dynamic
`-ddump-cmm-opt`	Dump the results of C-\- to C-\- optimising passes	dynamic
`-ddump-cmm-proc`	Dump the results of proc-point analysis	dynamic
`-ddump-cmm-procmap`	Dump the results of the C-\- proc-point map pass.	dynamic
`-ddump-cmm-raw`	Dump raw C-\-	dynamic
`-ddump-cmm-sink`	Dump the results of the C-\- sinking pass.	dynamic
`-ddump-cmm-sp`	Dump the results of the C-\- stack layout pass.	dynamic
`-ddump-cmm-split`	Dump the results of the C-\- proc-point splitting pass.	dynamic
`-ddump-cmm-switch`	Dump the results of switch lowering passes	dynamic
`-ddump-cmm-thread-sanitizer`	Dump the results of the C-\- ThreadSanitizer elaboration pass.	dynamic
`-ddump-cmm-verbose`	Write output from main C-\- pipeline passes to files	dynamic
`-ddump-cmm-verbose-by-proc`	Show output from main C-\- pipeline passes (grouped by proc)	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-cpr-signatures`	Dump CPR signatures	dynamic
`-ddump-cpranal`	Dump CPR analysis output	dynamic
`-ddump-cs-trace`	Trace constraint solver	dynamic
`-ddump-cse`	Dump CSE output	dynamic
`-ddump-debug`	Dump generated DWARF debug information	dynamic
`-ddump-deriv`	Dump deriving output	dynamic
`-ddump-dmd-signatures`	Dump top-level demand signatures	dynamic
`-ddump-dmdanal`	Dump demand analysis output	dynamic
`-ddump-ds`, `-ddump-ds-preopt`	Dump desugarer output.	dynamic
`-ddump-ec-trace`	Trace exhaustiveness checker	dynamic
`-ddump-exitify`	Dump output of the exitification pass.	dynamic
`-ddump-faststrings`	Dump the whole FastString table when finished	dynamic
`-ddump-file-prefix=⟨str⟩`	Set the prefix of the filenames used for debugging output.	dynamic
`-ddump-float-in`	Dump float in output	dynamic
`-ddump-foreign`	Dump `foreign export` stubs	dynamic
`-ddump-full-laziness`, `-ddump-float-out`	Dump full laziness pass output	dynamic
`-ddump-hie`	Dump the hie file syntax tree	dynamic
`-ddump-hpc`	An alias for `-ddump-ticked`.	dynamic
`-ddump-if-trace`	Trace interface files	dynamic
`-ddump-inlinings`	Dump inlinings performed by the simplifier.	dynamic
`-ddump-js`	Dump final JavaScript code	dynamic
`-ddump-json`	(deprecated) Use `-fdiagnostics-as-json` instead	dynamic
`-ddump-late-cc`	Dump core with late cost centres added	dynamic
`-ddump-liberate-case`	Dump liberate case output	dynamic
`-ddump-llvm`	Dump LLVM intermediate code.	dynamic
`-ddump-mod-map`	Dump the state of the module mapping database.	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-parsed-ast`	Dump parser output as a syntax tree	dynamic
`-ddump-prep`	Dump prepared core	dynamic
`-ddump-rn`	Dump renamer output	dynamic
`-ddump-rn-ast`	Dump renamer output as a syntax tree	dynamic
`-ddump-rn-stats`	Renamer stats	dynamic
`-ddump-rn-trace`	Trace renamer	dynamic
`-ddump-rtti`	Trace runtime type inference	dynamic
`-ddump-rule-firings`	Dump rule firing info	dynamic
`-ddump-rule-rewrites`	Dump detailed rule firing info	dynamic
`-ddump-rules`	Dump rewrite rules	dynamic
`-ddump-simpl`	Dump final simplifier output	dynamic
`-ddump-simpl-iterations`	Dump output from each simplifier iteration	dynamic
`-ddump-simpl-stats`	Dump simplifier stats	dynamic
`-ddump-simpl-trace`	Dump trace messages in simplifier	dynamic
`-ddump-spec`	Dump specialiser output	dynamic
`-ddump-spec-constr`	Dump specialiser output from SpecConstr	dynamic
`-ddump-splices`	Dump TH spliced expressions, and what they evaluate to	dynamic
`-ddump-static-argument-transformation`	Dump static argument transformation output	dynamic
`-ddump-stg`	(deprecated) Alias for `-ddump-stg-from-core`	dynamic
`-ddump-stg-cg`	Show output after Stg2Stg	dynamic
`-ddump-stg-final`	Show output of last STG pass.	dynamic
`-ddump-stg-from-core`	Show CoreToStg output	dynamic
`-ddump-stg-tags`	Show output of the tag inference pass.	dynamic
`-ddump-stg-unarised`	Show unarised STG	dynamic
`-ddump-str-signatures`	(deprecated) Alias for `-ddump-dmd-signatures`	dynamic
`-ddump-stranal`	(deprecated) Alias for `-ddump-dmdanal`	dynamic
`-ddump-tc`	Dump typechecker output	dynamic
`-ddump-tc-ast`	Dump typechecker output as a syntax tree	dynamic
`-ddump-tc-trace`	Trace typechecker	dynamic
`-ddump-ticked`	Dump the code instrumented by HPC (Observing Code Coverage).	dynamic
`-ddump-timings`	Dump per-pass timing and allocation statistics	dynamic
`-ddump-to-file`	Dump to files instead of stdout	dynamic
`-ddump-types`	Dump type signatures	dynamic
`-ddump-verbose-inlinings`	Dump all considered inlinings	dynamic
`-ddump-view-pattern-commoning`	Dump commoned view patterns	dynamic
`-ddump-worker-wrapper`	Dump worker-wrapper output	dynamic
`-dfaststring-stats`	Show statistics for fast string usage when finished	dynamic
`-dhex-word-literals`	Print values of type Word# in hexadecimal.	dynamic
`-dinitial-unique=⟨s⟩`	Start `UniqSupply` allocation from ⟨s⟩.	dynamic
`-dinline-check=⟨str⟩`	Dump information about inlining decisions	dynamic
`-dipe-stats`	Show statistics about IPE information	dynamic
`-dkeep-comments`	Include comments in the parser. Useful in combination with `-ddump-parsed-ast`.	dynamic
`-dlinear-core-lint`	Turn on internal sanity checking	dynamic
`-dlint`	Enable several common internal sanity checkers	dynamic
`-dno-debug-output`	Suppress unsolicited debugging output	dynamic	`-ddebug-output`
`-dno-typeable-binds`	Don't generate bindings for Typeable methods	dynamic
`-dppr-case-as-let`	Print single alternative case expressions as strict lets.	dynamic
`-dppr-cols=⟨n⟩`	Set the width of debugging output. For example `-dppr-cols200`	dynamic
`-dppr-debug`	Turn on debug printing (more verbose)	dynamic
`-dppr-user-length`	Set the depth for printing expressions in error msgs	dynamic
`-drule-check=⟨str⟩`	Dump information about potential rule application	dynamic
`-dshow-passes`	Print out each pass name as it happens	dynamic
`-dstg-lint`	STG pass sanity checking	dynamic
`-dsuppress-all`	In dumps, suppress everything (except for uniques) that is suppressible.	dynamic
`-dsuppress-coercion-types`	Suppress the printing of coercion types in Core dumps to make them shorter	dynamic
`-dsuppress-coercions`	Suppress the printing of coercions in Core dumps to make them shorter	dynamic
`-dsuppress-core-sizes`	Suppress the printing of core size stats per binding (since 9.4)	dynamic
`-dsuppress-idinfo`	Suppress extended information about identifiers where they are bound	dynamic
`-dsuppress-module-prefixes`	Suppress the printing of module qualification prefixes	dynamic
`-dsuppress-stg-free-vars`	Suppress the printing of closure free variable lists in STG output	dynamic
`-dsuppress-stg-reps`	Suppress rep annotations on STG args.	dynamic
`-dsuppress-ticks`	Suppress "ticks" in the pretty-printer output.	dynamic
`-dsuppress-timestamps`	Suppress timestamps in dumps	dynamic
`-dsuppress-type-applications`	Suppress type applications	dynamic
`-dsuppress-type-signatures`	Suppress type signatures	dynamic
`-dsuppress-unfoldings`	Suppress the printing of the stable unfolding of a variable at its binding site	dynamic
`-dsuppress-uniques`	Suppress the printing of uniques in debug output (easier to use `diff`)	dynamic
`-dsuppress-var-kinds`	Suppress the printing of variable kinds	dynamic
`-dtag-inference-checks`	Affirm tag inference results are correct at runtime.	dynamic
`-dth-dec-file`	Dump evaluated TH declarations into *.th.hs files	dynamic
`-dunique-increment=⟨i⟩`	Set the increment for the generated `Unique`'s to ⟨i⟩.	dynamic
`-dverbose-core2core`	Show output from each core-to-core pass	dynamic
`-dverbose-stg2stg`	Show output from each STG-to-STG pass	dynamic
`-falignment-sanitisation`	Compile with alignment checks for all info table dereferences.	dynamic
`-fcatch-nonexhaustive-cases`	Add a default `error` alternative to case expressions without a default alternative.	dynamic
`-fcheck-prim-bounds`	Instrument array primops with bounds checks.	dynamic
`-fcmm-thread-sanitizer`	Enable ThreadSanitizer instrumentation of memory accesses.	dynamic
`-fdistinct-constructor-tables`	Generate a fresh info table for each usage of a data constructor.	dynamic
`-fdump-with-ways`	Include the tag of the enabled ways in the extension of dump files.	dynamic
`-finfo-table-map`	Embed a lookup table in the generated binary which maps the address of an info table to the source position the closure originated from.	dynamic
`-finfo-table-map-with-fallback`	Include info tables with no source location information in the info table map.	dynamic	`-fno-info-table-map-with-fallback`
`-finfo-table-map-with-stack`	Include info tables for `STACK` closures in the info table map.	dynamic	`-fno-info-table-map-with-stack`
`-fllvm-fill-undef-with-garbage`	Intruct LLVM to fill dead STG registers with garbage	dynamic
`-fno-info-table-map-with-fallback`	Omit info tables with no source location information from the info table map.	dynamic	`-finfo-table-map-with-fallback`
`-fno-info-table-map-with-stack`	Omit info tables for `STACK` closures from the info table map.	dynamic	`-finfo-table-map-with-stack`
`-forig-thunk-info`	Generate `stg_orig_thunk_info` stack frames on thunk entry	dynamic
`-fproc-alignment`	Align functions at given boundary.	dynamic
`-funoptimized-core-for-interpreter`	Disable optimizations with the interpreter	dynamic	`-fno-unoptimized-core-for-interpreter`
`-g`, `-g⟨n⟩`	Produce DWARF debug information in compiled object files. ⟨n⟩ can be 0, 1, or 2, with higher numbers producing richer output. If ⟨n⟩ is omitted, level 2 is assumed.	dynamic

5.6.27. Miscellaneous compiler options¶

Flag	Description	Type	Reverse
`-ddump-mod-cycles`	Dump module cycles	dynamic
`-fdefer-out-of-scope-variables`	Convert variable out of scope variables errors into warnings. Implied by `-fdefer-type-errors`. See also `-Wdeferred-out-of-scope-variables`.	dynamic	`-fno-defer-out-of-scope-variables`
`-fdefer-type-errors`	Turn type errors into warnings, deferring the error until runtime. Implies `-fdefer-typed-holes` and `-fdefer-out-of-scope-variables`. See also `-Wdeferred-type-errors`.	dynamic	`-fno-defer-type-errors`
`-fdefer-typed-holes`	Convert typed hole errors into warnings, deferring the error until runtime. Implied by `-fdefer-type-errors`. See also `-Wtyped-holes`.	dynamic	`-fno-defer-typed-holes`
`-fexternal-interpreter`	Run interpreted code in a separate process	dynamic
`-ffamily-application-cache`	Use a cache when reducing type family applications	dynamic	`-fno-family-application-cache`
`-fglasgow-exts`	Deprecated. Enable most language extensions; see Controlling editions and extensions for exactly which ones.	dynamic	`-fno-glasgow-exts`
`-fno-safe-haskell`	Disable Safe Haskell	dynamic
`-ghcversion-file ⟨path to ghcversion.h⟩`	(GHC as a C compiler only) Use this `ghcversion.h` file	dynamic
`-H ⟨size⟩`	Set the minimum size of the heap to ⟨size⟩	dynamic
`-hidden-module ⟨module name⟩`	A module which should not be visible outside its unit.	dynamic
`-j[⟨n⟩]`	When compiling with `--make`, compile ⟨n⟩ modules in parallel.	dynamic
`-jsem`	When compiling with `--make`, coordinate with other processes through the semaphore ⟨sem⟩ to compile modules in parallel.	dynamic
`-reexported-module ⟨reexport-spec⟩`	A module which should be reexported from this unit.	dynamic
`-this-package-name ⟨unit-id⟩`	The name of the package which this module would be part of when installed.	dynamic
`-unit @⟨filename⟩`	Specify the options to build a specific unit.	dynamic
`-working-dir ⟨dir⟩`	Specify the directory a unit is expected to be compiled in.	dynamic