users_guide: Convert mkUserGuidePart generation to a Sphinx extension

This removes all dependencies the users guide had on `mkUserGuidePart`.
The generation of the flag reference table and the various pieces of the
man page is now entirely contained within the Spinx extension
`flags.py`. You can see the man page generation on the orphan page
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghc.html

The extension works by collecting all of the meta-data attached to the
`ghc-flag` directives and then formatting and displaying it at
`flag-print` directives. There is a single printing directive that can
be customized with two options, what format to display (table, list, or
block of flags) and an optional category to limit the output to
(verbosity, warnings, codegen, etc.).

New display formats can be added by creating a function
`generate_flag_xxx` (where `xxx` is a description of the format) which
takes a list of flags and a category and returns a new `xxx`. Then just
add a reference in the dispatch table `handlers`. That display can now
be run by passing `:type: xxx` to the `flag-print` directive.

`flags.py` contains two maps of settings that can be adjusted. The first
is a canonical list of flag categories, and the second sets default
categories for files.

The only functionality that Sphinx could not replace was the
`what_glasgow_exts_does.gen.rst` file. `mkUserGuidePart` actually just
reads the list of flags from `compiler/main/DynFlags.hs` which Sphinx
cannot do. As the flag is deprecated, I added the list as a static file
which can be updated manually.

Additionally, this patch updates every single documented flag with the
data from `mkUserGuidePart` to generate the reference table.

Fixes #11654 and, incidentally, #12155.

Reviewers: austin, bgamari

Subscribers: rwbarton, thomie

GHC Trac Issues: #11654, #12155

Differential Revision: https://phabricator.haskell.org/D3839

1 files changed, 283 insertions, 2 deletions

diff --git a/docs/users_guide/using-optimisation.rst b/docs/users_guide/using-optimisation.rst
index 15916b2690..763c778872 100644
--- a/docs/users_guide/using-optimisation.rst
+++ b/docs/users_guide/using-optimisation.rst
@@ -50,6 +50,10 @@ compile quickly; I'm not over-bothered about compiled-code quality.”
 So, for example, ``ghc -c Foo.hs``
 
 .. ghc-flag:: -O0
+    :shortdesc: Disable optimisations (default)
+    :type: dynamic
+    :reverse: -O
+    :category: optimization-levels
 
     Means "turn off all optimisation", reverting to the same settings as
     if no ``-O`` options had been specified. Saying ``-O0`` can be
@@ -58,6 +62,10 @@ So, for example, ``ghc -c Foo.hs``
 
 .. ghc-flag:: -O
               -O1
+    :shortdesc: Enable level 1 optimisations
+    :type: dynamic
+    :reverse: -O0
+    :category: optimization-levels
 
     .. index::
        single: optimise; normally
@@ -66,6 +74,10 @@ So, for example, ``ghc -c Foo.hs``
     it." Thus, for example: ``ghc -c -O Main.lhs``
 
 .. ghc-flag:: -O2
+    :shortdesc: Enable level 2 optimisations
+    :type: dynamic
+    :reverse: -O0
+    :category: optimization-levels
 
     .. index::
        single: optimise; aggressively
@@ -78,6 +90,11 @@ So, for example, ``ghc -c Foo.hs``
     on or off individually.
 
 .. ghc-flag:: -Odph
+    :shortdesc: Enable level 2 optimisations, set
+        ``-fmax-simplifier-iterations=20``
+        and ``-fsimplifier-phases=3``.
+    :type: dynamic
+    :category: optimization-levels
 
     .. index::
        single: optimise; DPH
@@ -109,6 +126,10 @@ need to set any of them explicitly. A flag ``-fwombat`` can be negated
 by saying ``-fno-wombat``.
 
 .. ghc-flag:: -fcase-merge
+    :shortdesc: Enable case-merging. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-case-merge
+    :category:
 
     :default: on
 
@@ -129,6 +150,10 @@ by saying ``-fno-wombat``.
              Green -> e2
 
 .. ghc-flag:: -fcase-folding
+    :shortdesc: Enable constant folding in case expressions. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-case-folding
+    :category:
 
     :default: on
 
@@ -148,12 +173,20 @@ by saying ``-fno-wombat``.
              _    -> let v = x `minusWord#` 10## in e3
 
 .. ghc-flag:: -fcall-arity
+    :shortdesc: Enable call-arity optimisation. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-call-arity
+    :category:
 
     :default: on
 
     Enable call-arity analysis.
 
 .. ghc-flag:: -fcmm-elim-common-blocks
+    :shortdesc: Enable Cmm common block elimination. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-cmm-elim-common-blocks
+    :category:
 
     :default: on
 
@@ -162,6 +195,10 @@ by saying ``-fno-wombat``.
     Cmm blocks and eliminate the duplicates.
 
 .. ghc-flag:: -fcmm-sink
+    :shortdesc: Enable Cmm sinking. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-cmm-sink
+    :category:
 
     :default: on
 
@@ -172,12 +209,20 @@ by saying ``-fno-wombat``.
     literals or registers.
 
 .. ghc-flag:: -fcpr-anal
+    :shortdesc: Turn on CPR analysis in the demand analyser. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-cpr-anal
+    :category:
 
     :default: on
 
     Turn on CPR analysis in the demand analyser.
 
 .. ghc-flag:: -fcse
+    :shortdesc: Enable common sub-expression elimination. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-cse
+    :category:
 
     :default: on
 
@@ -186,6 +231,11 @@ by saying ``-fno-wombat``.
     ``unsafePerformIO`` expressions that you don't want commoned-up.
 
 .. ghc-flag:: -fstg-cse
+    :shortdesc: Enable common sub-expression elimination on the STG
+        intermediate language
+    :type: dynamic
+    :reverse: -fno-stg-cse
+    :category:
 
     :default: on
 
@@ -194,6 +244,10 @@ by saying ``-fno-wombat``.
     that differ in their types, but not their represetation.
 
 .. ghc-flag:: -fdicts-cheap
+    :shortdesc: Make dictionary-valued expressions seem cheap to the optimiser.
+    :type: dynamic
+    :reverse: -fno-dicts-cheap
+    :category:
 
     :default: off
 
@@ -201,18 +255,31 @@ by saying ``-fno-wombat``.
     seem cheap to the optimiser.
 
 .. ghc-flag:: -fdicts-strict
+    :shortdesc: Make dictionaries strict
+    :type: dynamic
+    :reverse: -fno-dicts-strict
+    :category:
 
     :default: off
 
     Make dictionaries strict.
 
 .. ghc-flag:: -fdmd-tx-dict-sel
+    :shortdesc: Use a special demand transformer for dictionary selectors.
+        Always enabled by default.
+    :type: dynamic
+    :reverse: -fno-dmd-tx-dict-sel
+    :category:
 
     :default: on
 
     Use a special demand transformer for dictionary selectors.
 
 .. ghc-flag:: -fdo-eta-reduction
+    :shortdesc: Enable eta-reduction. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-do-eta-reduction
+    :category:
 
     :default: on
 
@@ -220,12 +287,19 @@ by saying ``-fno-wombat``.
     lambdas.
 
 .. ghc-flag:: -fdo-lambda-eta-expansion
+    :shortdesc: Enable lambda eta-expansion. Always enabled by default.
+    :type: dynamic
+    :reverse: -fno-do-lambda-eta-expansion
+    :category:
 
     :default: on
 
     Eta-expand let-bindings to increase their arity.
 
 .. ghc-flag:: -feager-blackholing
+    :shortdesc: Turn on :ref:`eager blackholing <parallel-compile-options>`
+    :type: dynamic
+    :category:
 
     :default: off
 
@@ -234,7 +308,13 @@ by saying ``-fno-wombat``.
     a shared-memory
     multiprocessor <http://community.haskell.org/~simonmar/papers/multiproc.pdf>`__.
 
+    See :ref:`parallel-compile-options` for a dicussion on its use.
+
 .. ghc-flag:: -fexcess-precision
+    :shortdesc: Enable excess intermediate precision
+    :type: dynamic
+    :reverse: -fno-excess-precision
+    :category:
 
     :default: off
 
@@ -250,6 +330,10 @@ by saying ``-fno-wombat``.
     :ref:`bugs-ghc`.
 
 .. ghc-flag:: -fexpose-all-unfoldings
+    :shortdesc: Expose all unfoldings, even for very large or recursive functions.
+    :type: dynamic
+    :reverse: -fno-expose-all-unfoldings
+    :category:
 
     :default: off
 
@@ -258,6 +342,10 @@ by saying ``-fno-wombat``.
     while usually GHC would avoid inlining larger functions.
 
 .. ghc-flag:: -ffloat-in
+    :shortdesc: Turn on the float-in transformation. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-float-in
+    :category:
 
     :default: on
 
@@ -279,6 +367,11 @@ by saying ``-fno-wombat``.
     allocation and helping the garbage collector and allocator.
 
 .. ghc-flag:: -ffull-laziness
+    :shortdesc: Turn on full laziness (floating bindings outwards).
+        Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-full-laziness
+    :category:
 
     :default: on
 
@@ -300,6 +393,11 @@ by saying ``-fno-wombat``.
        don't rely on it.
 
 .. ghc-flag:: -ffun-to-thunk
+    :shortdesc: Allow worker-wrapper to convert a function closure into a thunk
+        if the function does not use any of its arguments. Off by default.
+    :type: dynamic
+    :reverse: -fno-fun-to-thunk
+    :category:
 
     :default: off
 
@@ -309,6 +407,10 @@ by saying ``-fno-wombat``.
     This flag allows worker/wrapper to remove *all* value lambdas.
 
 .. ghc-flag:: -fignore-asserts
+    :shortdesc: Ignore assertions in the source. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-ignore-asserts
+    :category:
 
     :default: on
 
@@ -317,6 +419,10 @@ by saying ``-fno-wombat``.
     :ref:`assertions`).
 
 .. ghc-flag:: -fignore-interface-pragmas
+    :shortdesc: Ignore pragmas in interface files. Implied by :ghc-flag:`-O0` only.
+    :type: dynamic
+    :reverse: -fno-ignore-interface-pragmas
+    :category:
 
     :default: off
 
@@ -326,6 +432,11 @@ by saying ``-fno-wombat``.
     information.
 
 .. ghc-flag:: -flate-dmd-anal
+    :shortdesc: Run demand analysis again, at the end of the
+        simplification pipeline
+    :type: dynamic
+    :reverse: -fno-late-dmd-anal
+    :category:
 
     :default: off
 
@@ -337,6 +448,10 @@ by saying ``-fno-wombat``.
     so is the cost. See notes on the :ghc-wiki:`Trac wiki page <LateDmd>`.
 
 .. ghc-flag:: -fliberate-case
+    :shortdesc: Turn on the liberate-case transformation. Implied by :ghc-flag:`-O2`.
+    :type: dynamic
+    :reverse: -fno-liberate-case
+    :category:
 
     :default: off but enabled with :ghc-flag:`-O2`.
 
@@ -346,12 +461,22 @@ by saying ``-fno-wombat``.
     free variables rather than arguments.
 
 .. ghc-flag:: -fliberate-case-threshold=⟨n⟩
+    :shortdesc: *default: 2000.* Set the size threshold for the liberate-case
+        transformation to ⟨n⟩
+    :type: dynamic
+    :reverse: -fno-liberate-case-threshold
+    :category:
 
     :default: 2000
 
     Set the size threshold for the liberate-case transformation.
 
 .. ghc-flag:: -floopification
+    :shortdesc: Turn saturated self-recursive tail-calls into local jumps in the
+        generated assembly. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-loopification
+    :category:
 
     :default: on
 
@@ -360,6 +485,10 @@ by saying ``-fno-wombat``.
     function calls.
 
 .. ghc-flag:: -fmax-inline-alloc-size=⟨n⟩
+    :shortdesc: *default: 128.* Set the maximum size of inline array allocations
+        to ⟨n⟩ bytes (default: 128).
+    :type: dynamic
+    :category:
 
     :default: 128
 
@@ -369,12 +498,20 @@ by saying ``-fno-wombat``.
     value should be quite a bit smaller than the block size (typically: 4096).
 
 .. ghc-flag:: -fmax-inline-memcpy-insns=⟨n⟩
+    :shortdesc: *default: 32.* Inline ``memcpy`` calls if they would generate no
+        more than ⟨n⟩ pseudo instructions.
+    :type: dynamic
+    :category:
 
     :default: 32
 
     Inline ``memcpy`` calls if they would generate no more than ⟨n⟩ pseudo-instructions.
 
 .. ghc-flag:: -fmax-inline-memset-insns=⟨n⟩
+    :shortdesc: *default: 32.* Inline ``memset`` calls if they would generate no
+        more than ⟨n⟩ pseudo instructions
+    :type: dynamic
+    :category:
 
     :default: 32
 
@@ -382,7 +519,11 @@ by saying ``-fno-wombat``.
     instructions.
 
 .. ghc-flag:: -fmax-relevant-binds=⟨n⟩
-              -fno-max-relevant-bindings
+    :shortdesc: *default: 6.* Set the maximum number of bindings to display in
+        type error messages.
+    :type: dynamic
+    :reverse: -fno-max-relevant-bindings
+    :category:
 
     :default: 6
 
@@ -395,7 +536,11 @@ by saying ``-fno-wombat``.
     them too.
 
 .. ghc-flag:: -fmax-valid-substitutions=⟨n⟩
-              -fno-max-valid-substitutions
+    :shortdesc: *default: 6.* Set the maximum number of valid substitutions for
+        typed holes to display in type error messages.
+    :type: dynamic
+    :reverse: -fno-max-valid-substitutions
+    :category:
 
     :default: 6
 
@@ -405,6 +550,10 @@ by saying ``-fno-wombat``.
     ``-fno-max-valid-substitutions`` gives an unlimited number.
 
 .. ghc-flag:: -fmax-uncovered-patterns=⟨n⟩
+    :shortdesc: *default: 4.* Set the maximum number of patterns to display in
+        warnings about non-exhaustive ones.
+    :type: dynamic
+    :category:
 
     :default: 4
 
@@ -412,30 +561,48 @@ by saying ``-fno-wombat``.
     :ghc-flag:`-Wincomplete-patterns` and :ghc-flag:`-Wincomplete-uni-patterns`.
 
 .. ghc-flag:: -fmax-simplifier-iterations=⟨n⟩
+    :shortdesc: *default: 4.* Set the max iterations for the simplifier.
+    :type: dynamic
+    :category:
 
     :default: 4
 
     Sets the maximal number of iterations for the simplifier.
 
 .. ghc-flag:: -fmax-worker-args=⟨n⟩
+    :shortdesc: *default: 10.* If a worker has that many arguments, none will
+        be unpacked anymore.
+    :type: dynamic
+    :category:
 
     :default: 10
 
     If a worker has that many arguments, none will be unpacked anymore.
 
 .. ghc-flag:: -fno-opt-coercion
+    :shortdesc: Turn off the coercion optimiser
+    :type: dynamic
+    :category:
 
     :default: off
 
     Turn off the coercion optimiser.
 
 .. ghc-flag:: -fno-pre-inlining
+    :shortdesc: Turn off pre-inlining
+    :type: dynamic
+    :category:
 
     :default: off
 
     Turn off pre-inlining.
 
 .. ghc-flag:: -fno-state-hack
+    :shortdesc: 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.
+    :type: dynamic
+    :category:
 
     :default: off
 
@@ -445,6 +612,10 @@ by saying ``-fno-wombat``.
     and ST monad code, but it runs the risk of reducing sharing.
 
 .. ghc-flag:: -fomit-interface-pragmas
+    :shortdesc: Don't generate interface pragmas. Implied by :ghc-flag:`-O0` only.
+    :type: dynamic
+    :reverse: -fno-omit-interface-pragmas
+    :category:
 
     :default: off
 
@@ -458,6 +629,10 @@ by saying ``-fno-wombat``.
     type, not when they change their implementation).
 
 .. ghc-flag:: -fomit-yields
+    :shortdesc: Omit heap checks when no allocation is being performed.
+    :type: dynamic
+    :reverse: -fno-omit-yields
+    :category:
 
     :default: on
 
@@ -470,6 +645,12 @@ by saying ``-fno-wombat``.
     turned off, if you need to guarantee interruptibility.
 
 .. ghc-flag:: -fpedantic-bottoms
+    :shortdesc: Make GHC be more precise about its treatment of bottom (but see
+        also :ghc-flag:`-fno-state-hack`). In particular, GHC will not
+        eta-expand through a case expression.
+    :type: dynamic
+    :reverse: -fno-pedantic-bottoms
+    :category:
 
     Make GHC be more precise about its treatment of bottom (but see also
     :ghc-flag:`-fno-state-hack`). In particular, stop GHC eta-expanding through
@@ -477,6 +658,11 @@ by saying ``-fno-wombat``.
     using ``seq`` on partial applications.
 
 .. ghc-flag:: -fregs-graph
+    :shortdesc: Use the graph colouring register allocator for register
+        allocation in the native code generator. Implied by :ghc-flag:`-O2`.
+    :type: dynamic
+    :reverse: -fno-regs-graph
+    :category:
 
     :default: off due to a performance regression bug (:ghc-ticket:`7679`)
 
@@ -490,6 +676,11 @@ by saying ``-fno-wombat``.
     when faced with code with high register pressure :ghc-ticket:`8657`.
 
 .. ghc-flag:: -fregs-iterative
+    :shortdesc: Use the iterative coalescing graph colouring register allocator
+        in the native code generator.
+    :type: dynamic
+    :reverse: -fno-regs-iterative
+    :category:
 
     :default: off
 
@@ -500,12 +691,19 @@ by saying ``-fno-wombat``.
     during register allocation.
 
 .. ghc-flag:: -fsimplifier-phases=⟨n⟩
+    :shortdesc: *default: 2.* Set the number of phases for the simplifier.
+        Ignored with :ghc-flag:`-O0`.
+    :type: dynamic
+    :category:
 
     :default: 2
 
     Set the number of phases for the simplifier. Ignored with ``-O0``.
 
 .. ghc-flag:: -fsimpl-tick-factor=⟨n⟩
+    :shortdesc: *default: 100.* Set the percentage factor for simplifier ticks.
+    :type: dynamic
+    :category:
 
     :default: 100
 
@@ -526,6 +724,10 @@ by saying ``-fno-wombat``.
     accurately, because some numbers are very large.
 
 .. ghc-flag:: -fspec-constr
+    :shortdesc: Turn on the SpecConstr transformation. Implied by :ghc-flag:`-O2`.
+    :type: dynamic
+    :reverse: -fno-spec-constr
+    :category:
 
     :default: off but enabled by :ghc-flag:`-O2`.
 
@@ -590,6 +792,11 @@ by saying ``-fno-wombat``.
     cases.
 
 .. ghc-flag:: -fspec-constr-keen
+    :shortdesc: Specialize a call with an explicit constructor argument,
+        even if the argument is not scrutinised in the body of the function
+    :type: dynamic
+    :reverse: -fno-spec-constr-keen
+    :category:
 
     :default: off
 
@@ -600,6 +807,12 @@ by saying ``-fno-wombat``.
     that can itself be specialised.
 
 .. ghc-flag:: -fspec-constr-count=⟨n⟩
+    :shortdesc: default: 3.* Set to ⟨n⟩ the maximum number of specialisations that
+        will be created for any one function by the SpecConstr
+        transformation.
+    :type: dynamic
+    :reverse: -fno-spec-constr-count
+    :category:
 
     :default: 3
 
@@ -607,12 +820,21 @@ by saying ``-fno-wombat``.
     any one function by the SpecConstr transformation.
 
 .. ghc-flag:: -fspec-constr-threshold=⟨n⟩
+    :shortdesc: *default: 2000.* Set the size threshold for the SpecConstr
+        transformation to ⟨n⟩.
+    :type: dynamic
+    :reverse: -fno-spec-constr-threshold
+    :category:
 
     :default: 2000
 
     Set the size threshold for the SpecConstr transformation.
 
 .. ghc-flag:: -fspecialise
+    :shortdesc: Turn on specialisation of overloaded functions. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-specialise
+    :category:
 
     :default: on
 
@@ -623,6 +845,11 @@ by saying ``-fno-wombat``.
     specialised as well.
 
 .. ghc-flag:: -fspecialise-aggressively
+    :shortdesc: Turn on specialisation of overloaded functions regardless of
+        size, if unfolding is available
+    :type: dynamic
+    :reverse: -fno-specialise-aggressively
+    :category:
 
     :default: off
 
@@ -635,6 +862,11 @@ by saying ``-fno-wombat``.
 
 
 .. ghc-flag:: -fcross-module-specialise
+    :shortdesc: Turn on specialisation of overloaded functions imported from
+        other modules.
+    :type: dynamic
+    :reverse: -fno-cross-module-specialise
+    :category:
 
     :default: on
 
@@ -644,6 +876,11 @@ by saying ``-fno-wombat``.
     enabled (by ``-fspecialise``) for this to have any effect.
 
 .. ghc-flag:: -fsolve-constant-dicts
+    :shortdesc: When solving constraints, try to eagerly solve
+        super classes using available dictionaries.
+    :type: dynamic
+    :reverse: -fno-solve-constant-dicts
+    :category:
 
     :default: on
 
@@ -675,6 +912,10 @@ by saying ``-fno-wombat``.
 
 
 .. ghc-flag:: -fstatic-argument-transformation
+    :shortdesc: Turn on the static argument transformation.
+    :type: dynamic
+    :reverse: -fno-static-argument-transformation
+    :category:
 
     :default: off
 
@@ -684,6 +925,11 @@ by saying ``-fno-wombat``.
     thesis <http://research.microsoft.com/en-us/um/people/simonpj/papers/santos-thesis.ps.gz>`__
 
 .. ghc-flag:: -fstrictness
+    :shortdesc: Turn on strictness analysis.
+        Implied by :ghc-flag:`-O`. Implies :ghc-flag:`-fworker-wrapper`
+    :type: dynamic
+    :reverse: -fno-strictness
+    :category:
 
     :default: on
 
@@ -698,10 +944,18 @@ by saying ``-fno-wombat``.
     arguments.
 
 .. ghc-flag:: -fstrictness-before=⟨n⟩
+    :shortdesc: Run an additional strictness analysis before simplifier phase ⟨n⟩
+    :type: dynamic
+    :category:
 
     Run an additional strictness analysis before simplifier phase ⟨n⟩.
 
 .. ghc-flag:: -funbox-small-strict-fields
+    :shortdesc: Flatten strict constructor fields with a pointer-sized
+        representation. Implied by :ghc-flag:`-O`.
+    :type: dynamic
+    :reverse: -fno-unbox-small-strict-fields
+    :category:
 
     :default: on
 
@@ -737,6 +991,10 @@ by saying ``-fno-wombat``.
     they are technically larger than a pointer on those platforms.
 
 .. ghc-flag:: -funbox-strict-fields
+    :shortdesc: Flatten strict constructor fields
+    :type: dynamic
+    :reverse: -fno-unbox-strict-fields
+    :category:
 
     :default: off
 
@@ -760,6 +1018,9 @@ by saying ``-fno-wombat``.
     unbox strict fields which are "small".
 
 .. ghc-flag:: -funfolding-creation-threshold=⟨n⟩
+    :shortdesc: *default: 750.* Tweak unfolding settings.
+    :type: dynamic
+    :category:
 
     :default: 750
 
@@ -783,6 +1044,9 @@ by saying ``-fno-wombat``.
     useful.
 
 .. ghc-flag:: -funfolding-dict-discount=⟨n⟩
+    :shortdesc: *default: 30.* Tweak unfolding settings.
+    :type: dynamic
+    :category:
 
     :default: 30
 
@@ -793,6 +1057,9 @@ by saying ``-fno-wombat``.
     How eager should the compiler be to inline dictionaries?
 
 .. ghc-flag:: -funfolding-fun-discount=⟨n⟩
+    :shortdesc: *default: 60.* Tweak unfolding settings.
+    :type: dynamic
+    :category:
 
     :default: 60
 
@@ -803,6 +1070,9 @@ by saying ``-fno-wombat``.
     How eager should the compiler be to inline functions?
 
 .. ghc-flag:: -funfolding-keeness-factor=⟨n⟩
+    :shortdesc: *default: 1.5.* Tweak unfolding settings.
+    :type: dynamic
+    :category:
 
     :default: 1.5
 
@@ -813,6 +1083,9 @@ by saying ``-fno-wombat``.
     How eager should the compiler be to inline functions?
 
 .. ghc-flag:: -funfolding-use-threshold=⟨n⟩
+    :shortdesc: *default: 60.* Tweak unfolding settings.
+    :type: dynamic
+    :category:
 
     :default: 60
 
@@ -834,6 +1107,10 @@ by saying ``-fno-wombat``.
     potential inlining.
 
 .. ghc-flag:: -fvectorisation-avoidance
+    :shortdesc: Enable vectorisation avoidance. Always enabled by default.
+    :type: dynamic
+    :reverse: -fno-vectorisation-avoidance
+    :category:
 
     :default: on
 
@@ -852,6 +1129,10 @@ by saying ``-fno-wombat``.
     function would be better of unvectorised and if so, do just that.
 
 .. ghc-flag:: -fvectorise
+    :shortdesc: Enable vectorisation of nested data parallelism
+    :type: dynamic
+    :reverse: -fno-vectorise
+    :category:
 
     :default: off