1. 18 Jun, 2018 1 commit
  2. 04 Jun, 2018 1 commit
    • Matthew Pickering's avatar
      Provide `getWithUserData` and `putWithUserData` · 554bc7fc
      Matthew Pickering authored
      Summary:
      This makes it possible to serialise Names and FastStrings in user
      programs, for example, when writing a source plugin.
      
      When writing my first source plugin, I wanted to serialise names but it
      wasn't possible easily without exporting additional constructors. This
      interface is sufficient and abstracts nicely over the symbol table and
      dictionary.
      
      Reviewers: alpmestan, bgamari
      
      Reviewed By: alpmestan
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #15223
      
      Differential Revision: https://phabricator.haskell.org/D4782
      554bc7fc
  3. 17 Jan, 2018 1 commit
  4. 09 Nov, 2017 1 commit
  5. 25 Oct, 2017 1 commit
    • Douglas Wilson's avatar
      Fix space leak in BinIface.getSymbolTable · 1c15d8ed
      Douglas Wilson authored
      Replace a call to mapAccumR, which uses linear stack space, with a
      gadget that uses constant space.
      
      Remove an unused parameter from fromOnDiskName.
      
      The tests T1292_imports and T4239 are now reporting imported names in a
      different order. I don't completely understand why, but I presume it is
      because the symbol tables are now read more strictly. The new order
      seems better in T1792_imports, and equally random in T4239.
      
      There are several performance test improvements.
      
      Test Plan: ./validate
      
      Reviewers: austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: alexbiehl, rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D4124
      1c15d8ed
  6. 19 Sep, 2017 1 commit
    • Herbert Valerio Riedel's avatar
      compiler: introduce custom "GhcPrelude" Prelude · f63bc730
      Herbert Valerio Riedel authored
      This switches the compiler/ component to get compiled with
      -XNoImplicitPrelude and a `import GhcPrelude` is inserted in all
      modules.
      
      This is motivated by the upcoming "Prelude" re-export of
      `Semigroup((<>))` which would cause lots of name clashes in every
      modulewhich imports also `Outputable`
      
      Reviewers: austin, goldfire, bgamari, alanz, simonmar
      
      Reviewed By: bgamari
      
      Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari
      
      Differential Revision: https://phabricator.haskell.org/D3989
      f63bc730
  7. 15 Mar, 2017 1 commit
    • Ben Gamari's avatar
      Introduce putLogMsg · 086b514b
      Ben Gamari authored
      This factors out the repetition of (log_action dflags dflags) and will
      hopefully allow us to someday better abstract log output.
      
      Test Plan: Validate
      
      Reviewers: austin, hvr, goldfire
      
      Subscribers: rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D3334
      086b514b
  8. 03 Feb, 2017 1 commit
    • Sylvain Henry's avatar
      Ditch static flags · bbd3c399
      Sylvain Henry authored
      This patch converts the 4 lasting static flags (read from the command
      line and unsafely stored in immutable global variables) into dynamic
      flags. Most use cases have been converted into reading them from a DynFlags.
      
      In cases for which we don't have easy access to a DynFlags, we read from
      'unsafeGlobalDynFlags' that is set at the beginning of each 'runGhc'.
      It's not perfect (not thread-safe) but it is still better as we can
      set/unset these 4 flags before each run when using GHC API.
      
      Updates haddock submodule.
      
      Rebased and finished by: bgamari
      
      Test Plan: validate
      
      Reviewers: goldfire, erikd, hvr, austin, simonmar, bgamari
      
      Reviewed By: simonmar
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2839
      
      GHC Trac Issues: #8440
      bbd3c399
  9. 16 Dec, 2016 1 commit
  10. 14 Oct, 2016 1 commit
    • Ben Gamari's avatar
      Clean up handling of known-key Names in interface files · 34d933d6
      Ben Gamari authored
      Previously BinIface had some dedicated logic for handling tuple names in
      the symbol table. As it turns out, this logic was essentially dead code
      as it was superceded by the special handling of known-key things. Here
      we cull the tuple code-path and use the known-key codepath for all
      tuple-ish things.
      
      This had a surprising number of knock-on effects,
      
       * constraint tuple datacons had to be made known-key (previously they
         were not)
      
       * IfaceTopBndr was changed from being a synonym of OccName to a
         synonym of Name (since we now need to be able to deserialize Names
         directly from interface files)
      
       * the change to IfaceTopBndr complicated fingerprinting, since we need
         to ensure that we don't go looking for the fingerprint of the thing
         we are currently fingerprinting in the fingerprint environment (see
         notes in MkIface). Handling this required distinguishing between
         binding and non-binding Name occurrences in the Binary serializers.
      
       * the original name cache logic which previously lived in IfaceEnv has
         been moved to a new NameCache module
      
       * I ripped tuples and sums out of knownKeyNames since they introduce a
         very large number of entries. During interface file deserialization
         we use static functions (defined in the new KnownUniques module) to
         map from a Unique to a known-key Name (the Unique better correspond
         to a known-key name!) When we need to do an original name cache
         lookup we rely on the parser implemented in isBuiltInOcc_maybe.
      
       * HscMain.allKnownKeyNames was folded into PrelInfo.knownKeyNames.
      
       * Lots of comments were sprinkled about describing the new scheme.
      
      Updates haddock submodule.
      
      Test Plan: Validate
      
      Reviewers: niteria, simonpj, austin, hvr
      
      Reviewed By: simonpj
      
      Subscribers: simonmar, niteria, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2467
      
      GHC Trac Issues: #12532, #12415
      34d933d6
  11. 21 Jul, 2016 1 commit
    • Ömer Sinan Ağacan's avatar
      Implement unboxed sum primitive type · 714bebff
      Ömer Sinan Ağacan authored
      Summary:
      This patch implements primitive unboxed sum types, as described in
      https://ghc.haskell.org/trac/ghc/wiki/UnpackedSumTypes.
      
      Main changes are:
      
      - Add new syntax for unboxed sums types, terms and patterns. Hidden
        behind `-XUnboxedSums`.
      
      - Add unlifted unboxed sum type constructors and data constructors,
        extend type and pattern checkers and desugarer.
      
      - Add new RuntimeRep for unboxed sums.
      
      - Extend unarise pass to translate unboxed sums to unboxed tuples right
        before code generation.
      
      - Add `StgRubbishArg` to `StgArg`, and a new type `CmmArg` for better
        code generation when sum values are involved.
      
      - Add user manual section for unboxed sums.
      
      Some other changes:
      
      - Generalize `UbxTupleRep` to `MultiRep` and `UbxTupAlt` to
        `MultiValAlt` to be able to use those with both sums and tuples.
      
      - Don't use `tyConPrimRep` in `isVoidTy`: `tyConPrimRep` is really
        wrong, given an `Any` `TyCon`, there's no way to tell what its kind
        is, but `kindPrimRep` and in turn `tyConPrimRep` returns `PtrRep`.
      
      - Fix some bugs on the way: #12375.
      
      Not included in this patch:
      
      - Update Haddock for new the new unboxed sum syntax.
      
      - `TemplateHaskell` support is left as future work.
      
      For reviewers:
      
      - Front-end code is mostly trivial and adapted from unboxed tuple code
        for type checking, pattern checking, renaming, desugaring etc.
      
      - Main translation routines are in `RepType` and `UnariseStg`.
        Documentation in `UnariseStg` should be enough for understanding
        what's going on.
      
      Credits:
      
      - Johan Tibell wrote the initial front-end and interface file
        extensions.
      
      - Simon Peyton Jones reviewed this patch many times, wrote some code,
        and helped with debugging.
      
      Reviewers: bgamari, alanz, goldfire, RyanGlScott, simonpj, austin,
                 simonmar, hvr, erikd
      
      Reviewed By: simonpj
      
      Subscribers: Iceland_jack, ggreif, ezyang, RyanGlScott, goldfire,
                   thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D2259
      714bebff
  12. 20 Jul, 2016 2 commits
    • Ben Gamari's avatar
      Revert "Clean up interaction between name cache and built-in syntax" · 83e4f495
      Ben Gamari authored
      This reverts commit 9513fe6b.
      
      Sadly this broke with -DDEBUG.
      83e4f495
    • Ben Gamari's avatar
      Clean up interaction between name cache and built-in syntax · 9513fe6b
      Ben Gamari authored
      This cleans up various aspects of the handling of built-in syntax in the
      original name cache (hopefully resulting in a nice reduction in compiler
      allocations),
      
        * Remove tuple types from original name cache: There is really no
          reason for these to be in the name cache since we already handle
          them specially in interface files to ensure that we can resolve them
          directly to Names, avoiding extraneous name cache lookups.
      
        * Sadly it's not possible to remove all traces of tuples from the
          name cache, however. Namely we need to keep the tuple type
          representations in since otherwise they would need to be wired-in
      
        * Remove the special cases for (:), [], and (##) in isBuiltInOcc_maybe
          and rename it to isTupleOcc_maybe
      
        * Split lookupOrigNameCache into two variants,
      
           * lookupOrigNameCache': Merely looks up an OccName in the original
             name cache, making no attempt to resolve tuples
      
           * lookupOrigNameCache: Like the above but handles tuples as well.
             This is given the un-primed name since it does the "obvious"
             thing from the perspective of an API user, who knows nothing of
             our special treatment of tuples.
      
      Arriving at this design took a significant amount of iteration. The
      trail of debris leading here can be found in #11357.
      
      Thanks to ezyang and Simon for all of their help in coming to this
      solution.
      
      Test Plan: Validate
      
      Reviewers: goldfire, simonpj, austin
      
      Reviewed By: simonpj
      
      Subscribers: thomie, ezyang
      
      Differential Revision: https://phabricator.haskell.org/D2414
      
      GHC Trac Issues: #11357
      9513fe6b
  13. 03 Jun, 2016 1 commit
  14. 25 Feb, 2016 1 commit
    • barrucadu's avatar
      Print which warning-flag controls an emitted warning · bb5afd3c
      barrucadu authored
      Both gcc and clang tell which warning flag a reported warning can be
      controlled with, this patch makes ghc do the same. More generally, this
      allows for annotated compiler output, where an optional annotation is
      displayed in brackets after the severity.
      
      This also adds a new flag `-f(no-)show-warning-groups` to control
      whether to show which warning-group (such as `-Wall` or `-Wcompat`)
      a warning belongs to. This flag is on by default.
      
      This implements #10752
      
      Reviewed By: quchen, bgamari, hvr
      
      Differential Revision: https://phabricator.haskell.org/D1943
      bb5afd3c
  15. 24 Feb, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Address #11471 by putting RuntimeRep in kinds. · d8c64e86
      eir@cis.upenn.edu authored
      See Note [TYPE] in TysPrim. There are still some outstanding
      pieces in #11471 though, so this doesn't actually nail the bug.
      
      This commit also contains a few performance improvements:
      
      * Short-cut equality checking of nullary type syns
      
      * Compare types before kinds in eqType
      
      * INLINE coreViewOneStarKind
      
      * Store tycon binders separately from kinds.
      
      This resulted in a ~10% performance improvement in compiling
      the Cabal package. No change in functionality other than
      performance. (This affects the interface file format, though.)
      
      This commit updates the haddock submodule.
      d8c64e86
  16. 11 Dec, 2015 1 commit
    • eir@cis.upenn.edu's avatar
      Add kind equalities to GHC. · 67465497
      eir@cis.upenn.edu authored
      This implements the ideas originally put forward in
      "System FC with Explicit Kind Equality" (ICFP'13).
      
      There are several noteworthy changes with this patch:
       * We now have casts in types. These change the kind
         of a type. See new constructor `CastTy`.
      
       * All types and all constructors can be promoted.
         This includes GADT constructors. GADT pattern matches
         take place in type family equations. In Core,
         types can now be applied to coercions via the
         `CoercionTy` constructor.
      
       * Coercions can now be heterogeneous, relating types
         of different kinds. A coercion proving `t1 :: k1 ~ t2 :: k2`
         proves both that `t1` and `t2` are the same and also that
         `k1` and `k2` are the same.
      
       * The `Coercion` type has been significantly enhanced.
         The documentation in `docs/core-spec/core-spec.pdf` reflects
         the new reality.
      
       * The type of `*` is now `*`. No more `BOX`.
      
       * Users can write explicit kind variables in their code,
         anywhere they can write type variables. For backward compatibility,
         automatic inference of kind-variable binding is still permitted.
      
       * The new extension `TypeInType` turns on the new user-facing
         features.
      
       * Type families and synonyms are now promoted to kinds. This causes
         trouble with parsing `*`, leading to the somewhat awkward new
         `HsAppsTy` constructor for `HsType`. This is dispatched with in
         the renamer, where the kind `*` can be told apart from a
         type-level multiplication operator. Without `-XTypeInType` the
         old behavior persists. With `-XTypeInType`, you need to import
         `Data.Kind` to get `*`, also known as `Type`.
      
       * The kind-checking algorithms in TcHsType have been significantly
         rewritten to allow for enhanced kinds.
      
       * The new features are still quite experimental and may be in flux.
      
       * TODO: Several open tickets: #11195, #11196, #11197, #11198, #11203.
      
       * TODO: Update user manual.
      
      Tickets addressed: #9017, #9173, #7961, #10524, #8566, #11142.
      Updates Haddock submodule.
      67465497
  17. 15 Oct, 2015 1 commit
  18. 26 Aug, 2015 1 commit
  19. 18 May, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor tuple constraints · ffc21506
      Simon Peyton Jones authored
      Make tuple constraints be handled by a perfectly ordinary
      type class, with the component constraints being the
      superclasses:
          class (c1, c2) => (c2, c2)
      
      This change was provoked by
      
        #10359  inability to re-use a given tuple
                constraint as a whole
      
        #9858   confusion between term tuples
                and constraint tuples
      
      but it's generally a very nice simplification. We get rid of
       -  In Type, the TuplePred constructor of PredTree,
          and all the code that dealt with TuplePreds
       -  In TcEvidence, the constructors EvTupleMk, EvTupleSel
      
      See Note [How tuples work] in TysWiredIn.
      
      Of course, nothing is ever entirely simple. This one
      proved quite fiddly.
      
      - I did quite a bit of renaming, which makes this patch
        touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.
      
      - I made constraint tuples known-key rather than wired-in.
        This is different to boxed/unboxed tuples, but it proved
        awkward to have all the superclass selectors wired-in.
        Easier just to use the standard mechanims.
      
      - While I was fiddling with known-key names, I split the TH Name
        definitions out of DsMeta into a new module THNames.  That meant
        that the known-key names can all be gathered in PrelInfo, without
        causing module loops.
      
      - I found that the parser was parsing an import item like
            T( .. )
        as a *data constructor* T, and then using setRdrNameSpace to
        fix it.  Stupid!  So I changed the parser to parse a *type
        constructor* T, which means less use of setRdrNameSpace.
      
        I also improved setRdrNameSpace to behave better on Exact Names.
        Largely on priciple; I don't think it matters a lot.
      
      - When compiling a data type declaration for a wired-in thing like
        tuples (,), or lists, we don't really need to look at the
        declaration.  We have the wired-in thing!  And not doing so avoids
        having to line up the uniques for data constructor workers etc.
        See Note [Declarations for wired-in things]
      
      - I found that FunDeps.oclose wasn't taking superclasses into
        account; easily fixed.
      
      - Some error message refactoring for invalid constraints in TcValidity
      
      - Haddock needs to absorb the change too; so there is a submodule update
      ffc21506
  20. 14 May, 2015 1 commit
    • Austin Seipp's avatar
      Revert multiple commits · 3cf8ecdc
      Austin Seipp authored
      This reverts multiple commits from Simon:
      
        - 04a484ea Test Trac #10359
        - a9ccd37a Test Trac #10403
        - c0aae6f6 Test Trac #10248
        - eb6ca851 Make the "matchable-given" check happen first
        - ca173aa3 Add a case to checkValidTyCon
        - 51cbad15 Update haddock submodule
        - 6e1174da Separate transCloVarSet from fixVarSet
        - a8493e03 Fix imports in HscMain (stage2)
        - a154944b Two wibbles to fix the build
        - 5910a1bc Change in capitalisation of error msg
        - 130e93aa Refactor tuple constraints
        - 8da785d5 Delete commented-out line
      
      These break the build by causing Haddock to fail mysteriously when
      trying to examine GHC.Prim it seems.
      3cf8ecdc
  21. 13 May, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor tuple constraints · 130e93aa
      Simon Peyton Jones authored
      Make tuple constraints be handled by a perfectly ordinary
      type class, with the component constraints being the
      superclasses:
          class (c1, c2) => (c2, c2)
      
      This change was provoked by
      
        #10359  inability to re-use a given tuple
                constraint as a whole
      
        #9858   confusion between term tuples
                and constraint tuples
      
      but it's generally a very nice simplification. We get rid of
       -  In Type, the TuplePred constructor of PredTree,
          and all the code that dealt with TuplePreds
       -  In TcEvidence, the constructors EvTupleMk, EvTupleSel
      
      See Note [How tuples work] in TysWiredIn.
      
      Of course, nothing is ever entirely simple. This one
      proved quite fiddly.
      
      - I did quite a bit of renaming, which makes this patch
        touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.
      
      - I made constraint tuples known-key rather than wired-in.
        This is different to boxed/unboxed tuples, but it proved
        awkward to have all the superclass selectors wired-in.
        Easier just to use the standard mechanims.
      
      - While I was fiddling with known-key names, I split the TH Name
        definitions out of DsMeta into a new module THNames.  That meant
        that the known-key names can all be gathered in PrelInfo, without
        causing module loops.
      
      - I found that the parser was parsing an import item like
            T( .. )
        as a *data constructor* T, and then using setRdrNameSpace to
        fix it.  Stupid!  So I changed the parser to parse a *type
        constructor* T, which means less use of setRdrNameSpace.
      
        I also improved setRdrNameSpace to behave better on Exact Names.
        Largely on priciple; I don't think it matters a lot.
      
      - When compiling a data type declaration for a wired-in thing like
        tuples (,), or lists, we don't really need to look at the
        declaration.  We have the wired-in thing!  And not doing so avoids
        having to line up the uniques for data constructor workers etc.
        See Note [Declarations for wired-in things]
      
      - I found that FunDeps.oclose wasn't taking superclasses into
        account; easily fixed.
      
      - Some error message refactoring for invalid constraints in TcValidity
      130e93aa
  22. 01 May, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor TyCon to eliminate TupleTyCon · f6ab0f2d
      Simon Peyton Jones authored
      This makes TupleTyCon into an ordinary AlgTyCon, distinguished
      by its AlgTyConRhs, rather than a separate constructor of TyCon.
      
      It is preparatory work for making constraint tuples into classes,
      for which the ConstraintTuple tuples will have a TyConParent
      of a ClassTyCon.  Tuples didn't have this possiblity before.
      
      The patch affects other modules because I eliminated the
      unsatisfactory partial functions tupleTyConBoxity and tupleTyConSort.
      And tupleTyConArity which is just tyConArity.
      f6ab0f2d
  23. 21 Jul, 2014 1 commit
    • Edward Z. Yang's avatar
      Rename PackageId to PackageKey, distinguishing it from Cabal's PackageId. · 4bebab25
      Edward Z. Yang authored
      
      
      Summary:
      Previously, both Cabal and GHC defined the type PackageId, and we expected
      them to be roughly equivalent (but represented differently).  This refactoring
      separates these two notions.
      
      A package ID is a user-visible identifier; it's the thing you write in a
      Cabal file, e.g. containers-0.9.  The components of this ID are semantically
      meaningful, and decompose into a package name and a package vrsion.
      
      A package key is an opaque identifier used by GHC to generate linking symbols.
      Presently, it just consists of a package name and a package version, but
      pursuant to #9265 we are planning to extend it to record other information.
      Within a single executable, it uniquely identifies a package.  It is *not* an
      InstalledPackageId, as the choice of a package key affects the ABI of a package
      (whereas an InstalledPackageId is computed after compilation.)  Cabal computes
      a package key for the package and passes it to GHC using -package-name (now
      *extremely* misnamed).
      
      As an added bonus, we don't have to worry about shadowing anymore.
      
      As a follow on, we should introduce -current-package-key having the same role as
      -package-name, and deprecate the old flag.  This commit is just renaming.
      
      The haddock submodule needed to be updated.
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, simonmar, hvr, austin
      
      Subscribers: simonmar, relrod, carter
      
      Differential Revision: https://phabricator.haskell.org/D79
      
      Conflicts:
      	compiler/main/HscTypes.lhs
      	compiler/main/Packages.lhs
      	utils/haddock
      4bebab25
  24. 15 May, 2014 1 commit
    • Herbert Valerio Riedel's avatar
      Add LANGUAGE pragmas to compiler/ source files · 23892440
      Herbert Valerio Riedel authored
      In some cases, the layout of the LANGUAGE/OPTIONS_GHC lines has been
      reorganized, while following the convention, to
      
      - place `{-# LANGUAGE #-}` pragmas at the top of the source file, before
        any `{-# OPTIONS_GHC #-}`-lines.
      
      - Moreover, if the list of language extensions fit into a single
        `{-# LANGUAGE ... -#}`-line (shorter than 80 characters), keep it on one
        line. Otherwise split into `{-# LANGUAGE ... -#}`-lines for each
        individual language extension. In both cases, try to keep the
        enumeration alphabetically ordered.
        (The latter layout is preferable as it's more diff-friendly)
      
      While at it, this also replaces obsolete `{-# OPTIONS ... #-}` pragma
      occurences by `{-# OPTIONS_GHC ... #-}` pragmas.
      23892440
  25. 20 Jan, 2014 1 commit
    • Gergő Érdi's avatar
      Implement pattern synonyms · 4f8369bf
      Gergő Érdi authored
      This patch implements Pattern Synonyms (enabled by -XPatternSynonyms),
      allowing y ou to assign names to a pattern and abstract over it.
      
      The rundown is this:
      
        * Named patterns are introduced by the new 'pattern' keyword, and can
          be either *unidirectional* or *bidirectional*. A unidirectional
          pattern is, in the simplest sense, simply an 'alias' for a pattern,
          where the LHS may mention variables to occur in the RHS. A
          bidirectional pattern synonym occurs when a pattern may also be used
          in expression context.
      
        * Unidirectional patterns are declared like thus:
      
              pattern P x <- x:_
      
          The synonym 'P' may only occur in a pattern context:
      
              foo :: [Int] -> Maybe Int
              foo (P x) = Just x
              foo _     = Nothing
      
        * Bidirectional patterns are declared like thus:
      
              pattern P x y = [x, y]
      
          Here, P may not only occur as a pattern, but also as an expression
          when given values for 'x' and 'y', i.e.
      
              bar :: Int -> [Int]
              bar x = P x 10
      
        * Patterns can't yet have their own type signatures; signatures are inferred.
      
        * Pattern synonyms may not be recursive, c.f. type synonyms.
      
        * Pattern synonyms are also exported/imported using the 'pattern'
          keyword in an import/export decl, i.e.
      
              module Foo (pattern Bar) where ...
      
          Note that pattern synonyms share the namespace of constructors, so
          this disambiguation is required as a there may also be a 'Bar'
          type in scope as well as the 'Bar' pattern.
      
        * The semantics of a pattern synonym differ slightly from a typical
          pattern: when using a synonym, the pattern itself is matched,
          followed by all the arguments. This means that the strictness
          differs slightly:
      
              pattern P x y <- [x, y]
      
              f (P True True) = True
              f _             = False
      
              g [True, True] = True
              g _            = False
      
          In the example, while `g (False:undefined)` evaluates to False,
          `f (False:undefined)` results in undefined as both `x` and `y`
          arguments are matched to `True`.
      
      For more information, see the wiki:
      
          https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms
          https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms/Implementation
      
      Reviewed-by: Simon Peyton Jones's avatarSimon Peyton Jones <simonpj@microsoft.com>
      Signed-off-by: default avatarAustin Seipp <austin@well-typed.com>
      4f8369bf
  26. 29 Aug, 2013 1 commit
  27. 02 Aug, 2013 1 commit
  28. 27 Jul, 2013 1 commit
  29. 21 Jun, 2013 1 commit
    • eir@cis.upenn.edu's avatar
      Revise implementation of overlapping type family instances. · 569b2652
      eir@cis.upenn.edu authored
      This commit changes the syntax and story around overlapping type
      family instances. Before, we had "unbranched" instances and
      "branched" instances. Now, we have closed type families and
      open ones.
      
      The behavior of open families is completely unchanged. In particular,
      coincident overlap of open type family instances still works, despite
      emails to the contrary.
      
      A closed type family is declared like this:
      > type family F a where
      >   F Int = Bool
      >   F a   = Char
      The equations are tried in order, from top to bottom, subject to
      certain constraints, as described in the user manual. It is not
      allowed to declare an instance of a closed family.
      569b2652
  30. 30 May, 2013 1 commit
    • Simon Peyton Jones's avatar
      Make 'SPECIALISE instance' work again · 1ed04090
      Simon Peyton Jones authored
      This is a long-standing regression (Trac #7797), which meant that in
      particular the Eq [Char] instance does not get specialised.
      (The *methods* do, but the dictionary itself doesn't.)  So when you
      call a function
           f :: Eq a => blah
      on a string type (ie a=[Char]), 7.6 passes a dictionary of un-specialised
      methods.
      
      This only matters when calling an overloaded function from a
      specialised context, but that does matter in some programs.  I
      remember (though I cannot find the details) that Nick Frisby discovered
      this to be the source of some pretty solid performanc regresisons.
      
      Anyway it works now. The key change is that a DFunUnfolding now takes
      a form that is both simpler than before (the DFunArg type is eliminated)
      and more general:
      
      data Unfolding
        = ...
        | DFunUnfolding {     -- The Unfolding of a DFunId
          			-- See Note [DFun unfoldings]
            		  	--     df = /\a1..am. \d1..dn. MkD t1 .. tk
                              --                                 (op1 a1..am d1..dn)
           		      	--     	    	      	       	   (op2 a1..am d1..dn)
              df_bndrs :: [Var],      -- The bound variables [a1..m],[d1..dn]
              df_con   :: DataCon,    -- The dictionary data constructor (never a newtype datacon)
              df_args  :: [CoreExpr]  -- Args of the data con: types, superclasses and methods,
          }                           -- in positional order
      
      That in turn allowed me to re-enable the DFunUnfolding specialisation in
      DsBinds.  Lots of details here in TcInstDcls:
      	  Note [SPECIALISE instance pragmas]
      
      I also did some refactoring, in particular to pass the InScopeSet to
      exprIsConApp_maybe (which in turn means it has to go to a RuleFun).
      
      NB: Interface file format has changed!
      1ed04090
  31. 30 Jan, 2013 1 commit
  32. 28 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      More refactoring of FamInst/FamInstEnv; finally fixes Trac #7524 · a98e51ec
      Simon Peyton Jones authored
      Quite a bit of tidying up here; the fix to #7524 is actually
      only a small part.
      
      * Be fully clear that the cab_tvs in a CoAxBranch are not
        fresh.  See Note [CoAxBranch type variables] in CoAxiom.
      
      * Use CoAxBranch to replace the ATDfeault type in Class.
        CoAxBranch is perfect here.  This change allowed me to
        delete quite a bit of boilerplate code, including the
        corresponding IfaceSynType.
      
      * Tidy up the construction of CoAxBranches, and when FamIntBranch is
        freshened.  The latter onw happens only in FamInst.newFamInst.
      
      * Tidy the tyvars of a CoAxBranch when we build them, done in
        FamInst.mkCoAxBranch.  See Note [Tidy axioms when we build them]
        in that module.  This is what fixes #7524.
      
      Much niceer now.
      a98e51ec
  33. 25 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Refactor and improve the promotion inference · 09ff0e0d
      Simon Peyton Jones authored
      It should be the case that either an entire mutually recursive
      group of data type declarations can be promoted, or none of them.
      It's really odd to promote some data constructors of a type but
      not others. Eg
        data T a = T1 a | T2 Int
      Here T1 is sort-of-promotable but T2 isn't (becuase Int isn't
      promotable).
      
      This patch makes it all-or-nothing. At the same time I've made
      the TyCon point to its promoted cousin (via the tcPromoted field
      of an AlgTyCon), as well as vice versa (via the ty_con field of
      PromotedTyCon).
      
      The inference for the group is done in TcTyDecls, the same place
      that infers which data types are recursive, another global question.
      09ff0e0d
  34. 17 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Major patch to implement the new Demand Analyser · 0831a12e
      Simon Peyton Jones authored
      This patch is the result of Ilya Sergey's internship at MSR.  It
      constitutes a thorough overhaul and simplification of the demand
      analyser.  It makes a solid foundation on which we can now build.
      Main changes are
      
      * Instead of having one combined type for Demand, a Demand is
         now a pair (JointDmd) of
            - a StrDmd and
            - an AbsDmd.
         This allows strictness and absence to be though about quite
         orthogonally, and greatly reduces brain melt-down.
      
      * Similarly in the DmdResult type, it's a pair of
           - a PureResult (indicating only divergence/non-divergence)
           - a CPRResult (which deals only with the CPR property
      
      * In IdInfo, the
          strictnessInfo field contains a StrictSig, not a Maybe StrictSig
          demandInfo     field contains a Demand, not a Maybe Demand
        We don't need Nothing (to indicate no strictness/demand info)
        any more; topSig/topDmd will do.
      
      * Remove "boxity" analysis entirely.  This was an attempt to
        avoid "reboxing", but it added complexity, is extremely
        ad-hoc, and makes very little difference in practice.
      
      * Remove the "unboxing strategy" computation. This was an an
        attempt to ensure that a worker didn't get zillions of
        arguments by unboxing big tuples.  But in fact removing it
        DRAMATICALLY reduces allocation in an inner loop of the
        I/O library (where the threshold argument-count had been
        set just too low).  It's exceptional to have a zillion arguments
        and I don't think it's worth the complexity, especially since
        it turned out to have a serious performance hit.
      
      * Remove quite a bit of ad-hoc cruft
      
      * Move worthSplittingFun, worthSplittingThunk from WorkWrap to
        Demand. This allows JointDmd to be fully abstract, examined
        only inside Demand.
      
      Everything else really follows from these changes.
      
      All of this is really just refactoring, so we don't expect
      big performance changes, but acutally the numbers look quite
      good.  Here is a full nofib run with some highlights identified:
      
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
               expert          -2.6%    -15.5%      0.00      0.00     +0.0%
                fluid          -2.4%     -7.1%      0.01      0.01     +0.0%
                   gg          -2.5%    -28.9%      0.02      0.02    -33.3%
            integrate          -2.6%     +3.2%     +2.6%     +2.6%     +0.0%
              mandel2          -2.6%     +4.2%      0.01      0.01     +0.0%
             nucleic2          -2.0%    -16.3%      0.11      0.11     +0.0%
                 para          -2.6%    -20.0%    -11.8%    -11.7%     +0.0%
               parser          -2.5%    -17.9%      0.05      0.05     +0.0%
               prolog          -2.6%    -13.0%      0.00      0.00     +0.0%
               puzzle          -2.6%     +2.2%     +0.8%     +0.8%     +0.0%
              sorting          -2.6%    -35.9%      0.00      0.00     +0.0%
             treejoin          -2.6%    -52.2%     -9.8%     -9.9%     +0.0%
      --------------------------------------------------------------------------------
                  Min          -2.7%    -52.2%    -11.8%    -11.7%    -33.3%
                  Max          -1.8%     +4.2%    +10.5%    +10.5%     +7.7%
       Geometric Mean          -2.5%     -2.8%     -0.4%     -0.5%     -0.4%
      
      Things to note
      
      * Binary sizes are smaller. I don't know why, but it's good.
      
      * Allocation is sometiemes a *lot* smaller. I believe that all the big numbers
        (I checked treejoin, gg, sorting) arise from one place, namely a function
        GHC.IO.Encoding.UTF8.utf8_decode, which is strict in two Buffers both of
        which have several arugments.  Not w/w'ing both arguments (which is what
        we did before) has a big effect.  So the big win in actually somewhat
        accidental, gained by removing the "unboxing strategy" code.
      
      * A couple of benchmarks allocate slightly more.  This turns out
        to be due to reboxing (integrate).  But the biggest increase is
        mandel2, and *that* turned out also to be a somewhat accidental
        loss of CSE, and pointed the way to doing better CSE: see Trac
        #7596.
      
      * Runtimes are never very reliable, but seem to improve very slightly.
      
      All in all, a good piece of work.  Thank you Ilya!
      0831a12e
  35. 23 Dec, 2012 1 commit
    • Simon Peyton Jones's avatar
      Make {-# UNPACK #-} work for type/data family invocations · 1ee1cd41
      Simon Peyton Jones authored
      This fixes most of Trac #3990.  Consider
        data family D a
        data instance D Double = CD Int Int
        data T = T {-# UNPACK #-} !(D Double)
      Then we want the (D Double unpacked).
      
      To do this we need to construct a suitable coercion, and it's much
      safer to record that coercion in the interface file, lest the in-scope
      instances differ somehow.  That in turn means elaborating the HsBang
      type to include a coercion.
      
      To do that I moved HsBang from BasicTypes to DataCon, which caused
      quite a few minor knock-on changes.
      
      Interface-file format has changed!
      
      Still to do: need to do knot-tying to allow instances to take effect
      within the same module.
      1ee1cd41
  36. 22 Dec, 2012 1 commit
    • eir@cis.upenn.edu's avatar
      Implement overlapping type family instances. · 8366792e
      eir@cis.upenn.edu authored
      An ordered, overlapping type family instance is introduced by 'type
      instance
      where', followed by equations. See the new section in the user manual
      (7.7.2.2) for details. The canonical example is Boolean equality at the
      type
      level:
      
      type family Equals (a :: k) (b :: k) :: Bool
      type instance where
        Equals a a = True
        Equals a b = False
      
      A branched family instance, such as this one, checks its equations in
      order
      and applies only the first the matches. As explained in the note
      [Instance
      checking within groups] in FamInstEnv.lhs, we must be careful not to
      simplify,
      say, (Equals Int b) to False, because b might later unify with Int.
      
      This commit includes all of the commits on the overlapping-tyfams
      branch. SPJ
      requested that I combine all my commits over the past several months
      into one
      monolithic commit. The following GHC repos are affected: ghc, testsuite,
      utils/haddock, libraries/template-haskell, and libraries/dph.
      
      Here are some details for the interested:
      
      - The definition of CoAxiom has been moved from TyCon.lhs to a
        new file CoAxiom.lhs. I made this decision because of the
        number of definitions necessary to support BranchList.
      
      - BranchList is a GADT whose type tracks whether it is a
        singleton list or not-necessarily-a-singleton-list. The reason
        I introduced this type is to increase static checking of places
        where GHC code assumes that a FamInst or CoAxiom is indeed a
        singleton. This assumption takes place roughly 10 times
        throughout the code. I was worried that a future change to GHC
        would invalidate the assumption, and GHC might subtly fail to
        do the right thing. By explicitly labeling CoAxioms and
        FamInsts as being Unbranched (singleton) or
        Branched (not-necessarily-singleton), we make this assumption
        explicit and checkable. Furthermore, to enforce the accuracy of
        this label, the list of branches of a CoAxiom or FamInst is
        stored using a BranchList, whose constructors constrain its
        type index appropriately.
      
      I think that the decision to use BranchList is probably the most
      controversial decision I made from a code design point of view.
      Although I provide conversions to/from ordinary lists, it is more
      efficient to use the brList... functions provided in CoAxiom than
      always to convert. The use of these functions does not wander far
      from the core CoAxiom/FamInst logic.
      
      BranchLists are motivated and explained in the note [Branched axioms] in
      CoAxiom.lhs.
      
      - The CoAxiom type has changed significantly. You can see the new
        type in CoAxiom.lhs. It uses a CoAxBranch type to track
        branches of the CoAxiom. Correspondingly various functions
        producing and consuming CoAxioms had to change, including the
        binary layout of interface files.
      
      - To get branched axioms to work correctly, it is important to have a
        notion
        of type "apartness": two types are apart if they cannot unify, and no
        substitution of variables can ever get them to unify, even after type
      family
        simplification. (This is different than the normal failure to unify
      because
        of the type family bit.) This notion in encoded in tcApartTys, in
      Unify.lhs.
        Because apartness is finer-grained than unification, the tcUnifyTys
      now
        calls tcApartTys.
      
      - CoreLinting axioms has been updated, both to reflect the new
        form of CoAxiom and to enforce the apartness rules of branch
        application. The formalization of the new rules is in
        docs/core-spec/core-spec.pdf.
      
      - The FamInst type (in types/FamInstEnv.lhs) has changed
        significantly, paralleling the changes to CoAxiom. Of course,
        this forced minor changes in many files.
      
      - There are several new Notes in FamInstEnv.lhs, including one
        discussing confluent overlap and why we're not doing it.
      
      - lookupFamInstEnv, lookupFamInstEnvConflicts, and
        lookup_fam_inst_env' (the function that actually does the work)
        have all been more-or-less completely rewritten. There is a
        Note [lookup_fam_inst_env' implementation] describing the
        implementation. One of the changes that affects other files is
        to change the type of matches from a pair of (FamInst, [Type])
        to a new datatype (which now includes the index of the matching
        branch). This seemed a better design.
      
      - The TySynInstD constructor in Template Haskell was updated to
        use the new datatype TySynEqn. I also bumped the TH version
        number, requiring changes to DPH cabal files. (That's why the
        DPH repo has an overlapping-tyfams branch.)
      
      - As SPJ requested, I refactored some of the code in HsDecls:
      
       * splitting up TyDecl into SynDecl and DataDecl, correspondingly
         changing HsTyDefn to HsDataDefn (with only one constructor)
      
       * splitting FamInstD into TyFamInstD and DataFamInstD and
         splitting FamInstDecl into DataFamInstDecl and TyFamInstDecl
      
       * making the ClsInstD take a ClsInstDecl, for parallelism with
         InstDecl's other constructors
      
       * changing constructor TyFamily into FamDecl
      
       * creating a FamilyDecl type that stores the details for a family
         declaration; this is useful because FamilyDecls can appear in classes
      but
         other decls cannot
      
       * restricting the associated types and associated type defaults for a
       * class
         to be the new, more restrictive types
      
       * splitting cid_fam_insts into cid_tyfam_insts and cid_datafam_insts,
         according to the new types
      
       * perhaps one or two more that I'm overlooking
      
      None of these changes has far-reaching implications.
      
      - The user manual, section 7.7.2.2, is updated to describe the new type
        family
        instances.
      8366792e
  37. 14 Dec, 2012 1 commit
    • Simon Peyton Jones's avatar
      Major refactoring of the way that UNPACK pragmas are handled · faa8ff40
      Simon Peyton Jones authored
      The situation was pretty dire.  The way in which data constructors
      were handled, notably the mapping between their *source* argument types
      and their *representation* argument types (after seq'ing and unpacking)
      was scattered in three different places, and hard to keep in sync.
      
      Now it is all in one place:
      
       * The dcRep field of a DataCon gives its representation,
         specified by a DataConRep
      
       * As well as having the wrapper, the DataConRep has a "boxer"
         of type DataConBoxer (defined in MkId for loopy reasons).
         The boxer used at a pattern match to reconstruct the source-level
         arguments from the rep-level bindings in the pattern match.
      
       * The unboxing in the wrapper and the boxing in the boxer are dual,
         and are now constructed together, by MkId.mkDataConRep. This is
         the key function of this change.
      
       * All the computeBoxingStrategy code in TcTyClsDcls disappears.
      
      Much nicer.
      
      There is a little bit of refactoring left to do; the strange
      deepSplitProductType functions are now called only in WwLib, so
      I moved them there, and I think they could be tidied up further.
      faa8ff40
  38. 29 Nov, 2012 1 commit
  39. 18 Sep, 2012 1 commit
    • Simon Peyton Jones's avatar
      Make a start towards eta-rules and injective families · 58470fb7
      Simon Peyton Jones authored
      * Make Any into a type family (which it should always have been)
        This is to support the future introduction of eta rules for
        product types (see email on ghc-users title "PolyKind issue"
        early Sept 2012)
      
      * Add the *internal* data type support for
          (a) closed type families [so that you can't give
              type instance for 'Any']
          (b) injective type families [because Any is really
              injective]
        This amounts to two boolean flags on the SynFamilyTyCon
        constructor of TyCon.SynTyConRhs.
      
      There is some knock-on effect, but all of a routine nature.
      
      It remains to offer source syntax for either closed or
      injective families.
      58470fb7