1. 24 May, 2016 2 commits
    • niteria's avatar
      Document some benign nondeterminism · 4c6e69d5
      niteria authored
      I've changed the functions to their nonDet equivalents and explained
      why they're OK there. This allowed me to remove foldNameSet,
      foldVarEnv, foldVarEnv_Directly, foldVarSet and foldUFM_Directly.
      
      Test Plan: ./validate, there should be no change in behavior
      
      Reviewers: simonpj, simonmar, austin, goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2244
      
      GHC Trac Issues: #4012
      4c6e69d5
    • Gabor Greif's avatar
      Spelling · 1bf5c126
      Gabor Greif authored
      1bf5c126
  2. 18 May, 2016 1 commit
    • niteria's avatar
      Make inert_model and inert_eqs deterministic sets · fffe3a25
      niteria authored
      The order inert_model and intert_eqs fold affects the order that the
      typechecker looks at things. I've been able to experimentally confirm
      that the order of equalities and the order of the model matter for
      determinism. This is just a straigthforward replacement of
      nondeterministic VarEnv for deterministic DVarEnv.
      
      Test Plan: ./validate
      
      Reviewers: simonpj, goldfire, austin, bgamari, simonmar
      
      Reviewed By: simonmar
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2232
      
      GHC Trac Issues: #4012
      fffe3a25
  3. 12 May, 2016 2 commits
    • niteria's avatar
      Refactor some ppr functions to use pprUFM · 5416fadb
      niteria authored
      Nondeterminism doesn't matter in these places and pprUFM makes
      it obvious. I've flipped the order of arguments for convenience.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, bgamari, austin, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2205
      
      GHC Trac Issues: #4012
      5416fadb
    • niteria's avatar
      Kill varEnvElts in specImports · 6bf0eef7
      niteria authored
      We need the order of specialized binds and rules to be deterministic,
      so we use a deterministic set here.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, bgamari, austin, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2197
      
      GHC Trac Issues: #4012
      6bf0eef7
  4. 11 May, 2016 1 commit
    • niteria's avatar
      Document SCC determinism · 3edbd091
      niteria authored
      I've documented the guarantees that stronglyConnCompFromEdgedVertices
      provides and commented on the call sites to explain why they are
      OK from determinism standpoint. I've changed the functions to
      nonDetUFM versions, so that it's explicit they could introduce
      nondeterminism.  I haven't defined container (VarSet, NameSet)
      specific versions, so that we have less functions to worry about.
      
      Test Plan: this is mostly just documentation,
      it should have no runtime effect
      
      Reviewers: bgamari, simonmar, austin, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2194
      
      GHC Trac Issues: #4012
      3edbd091
  5. 10 May, 2016 1 commit
    • niteria's avatar
      Make simplifyInstanceContexts deterministic · b58b0e18
      niteria authored
      simplifyInstanceContexts used cmpType which is nondeterministic
      for canonicalising typeclass constraints in derived instances.
      Following changes make it deterministic as explained by the
      Note [Deterministic simplifyInstanceContexts].
      
      Test Plan: ./validate
      
      Reviewers: simonmar, goldfire, simonpj, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2173
      
      GHC Trac Issues: #4012
      b58b0e18
  6. 04 May, 2016 1 commit
    • niteria's avatar
      Kill non-deterministic foldUFM in TrieMap and TcAppMap · ad4392c1
      niteria authored
      Summary:
      foldUFM introduces unnecessary non-determinism that actually
      leads to different generated code as explained in
      Note [TrieMap determinism].
      
      As we're switching from UniqFM to UniqDFM here you might be
      concerned about performance. There's nothing that ./validate
      detects. nofib reports no change in Compile Allocations, but
      Compile Time got better on some tests and worse on some,
      yielding this summary:
      
              -1 s.d.                -----            -3.8%
              +1 s.d.                -----            +5.4%
              Average                -----            +0.7%
      
      This is not a fair comparison as the order of Uniques
      changes what GHC is actually doing. One benefit from making
      this deterministic is also that it will make the
      performance results more stable.
      
      Full nofib results: P108
      
      Test Plan: ./validate, nofib
      
      Reviewers: goldfire, simonpj, simonmar, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2169
      
      GHC Trac Issues: #4012
      ad4392c1
  7. 30 Apr, 2016 1 commit
  8. 28 Apr, 2016 6 commits
    • niteria's avatar
      Remove unused foldNameEnv · 031de8bb
      niteria authored
      foldNameEnv is nondeterministic in the general case and it's
      currently unused so we can remove it.
      031de8bb
    • niteria's avatar
      Kill mapUniqSet · 73129231
      niteria authored
      Note [Unsound mapUniqSet] explains why it got removed.
      
      Test Plan: build ghc
      
      Reviewers: simonpj, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie, simonmar
      
      Differential Revision: https://phabricator.haskell.org/D2152
      73129231
    • niteria's avatar
      Add uniqSetAny and uniqSetAll and use them · 3c426b05
      niteria authored
      There are couple of places where we do `foldUniqSet` just to
      compute `any` or `all`. `foldUniqSet` is non-deterministic in the
      general case and `any` and `all` also read nicer.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, goldfire, simonpj, bgamari, austin
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2156
      
      GHC Trac Issues: #4012
      3c426b05
    • niteria's avatar
      Kill unused foldOccSet · 3a53380d
      niteria authored
      foldOccSet if used would be a potential source of nondeterminism.
      Since it's not used we can just remove it.
      3a53380d
    • Simon Peyton Jones's avatar
      Refactor RecordPatSynField, FieldLabel · 3dce4f2d
      Simon Peyton Jones authored
      This patch uses the named fields of
       * FieldLabel
       * RecordPatSynField
      in construction and pattern matching. The fields
      existed before, but we were often using positional notation.
      
      Also a minor refactor of the API of mkPatSynRecSelBinds
      
      No change in functionality
      3dce4f2d
    • niteria's avatar
      Expand the comment on pprVarSet · fa3ba060
      niteria authored
      fa3ba060
  9. 27 Apr, 2016 1 commit
    • Joachim Breitner's avatar
      Implement the state hack without modifiyng OneShotInfo · a48ebcc4
      Joachim Breitner authored
      Previously, the state hack would be implemented in mkLocalId, by looking
      at the type, and setting the OneShot flag accordingly.
      
      This patch changes this so that the OneShot flag faithfully represents
      what our various analyses found out, and the State Hack is implemented
      by adjusting the accessors, in particular isOneShotBndr and
      idStateHackOneShotInfo. This makes it easier to understand what's going
      on in the analyses, and de-clutters core dumps and interface files.
      
      I don’t expect any change in behaviour, at least not in non-fringe
      cases.
      a48ebcc4
  10. 26 Apr, 2016 1 commit
    • niteria's avatar
      Kill varSetElemsWellScoped in quantifyTyVars · c9bcaf31
      niteria authored
      varSetElemsWellScoped introduces unnecessary non-determinism in
      inferred type signatures.
      Removing this instance required changing the representation of
      TcDepVars to use deterministic sets.
      This is the last occurence of varSetElemsWellScoped, allowing me to
      finally remove it.
      
      Test Plan:
      ./validate
      I will update the expected outputs when commiting, some reordering
      of type variables in types is expected.
      
      Reviewers: goldfire, simonpj, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: thomie, simonmar
      
      Differential Revision: https://phabricator.haskell.org/D2135
      
      GHC Trac Issues: #4012
      c9bcaf31
  11. 22 Apr, 2016 2 commits
    • niteria's avatar
      Make benign non-determinism in pretty-printing more obvious · 0f96686b
      niteria authored
      This change takes us one step closer to being able to remove
      `varSetElemsWellScoped`. The end goal is to make every source
      of non-determinism obvious at the source level, so that when
      we achieve determinism it doesn't get broken accidentally.
      
      Test Plan: compile GHC
      
      Reviewers: simonmar, goldfire, simonpj, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2123
      
      GHC Trac Issues: #4012
      0f96686b
    • Simon Peyton Jones's avatar
      Warn about simplifiable class constraints · 9421b0c7
      Simon Peyton Jones authored
      Provoked by Trac #11948, this patch adds a new warning to GHC
      
        -Wsimplifiable-class-constraints
      
      It warns if you write a class constraint in a type signature that
      can be simplified by an existing instance declaration.  Almost always
      this means you should simplify it right now; type inference is very
      fragile without it, as #11948 shows.
      
      I've put the warning as on-by-default, but I suppose that if there are
      howls of protest we can move it out (as happened for -Wredundant-constraints.
      
      It actually found an example of an over-complicated context in CmmNode.
      
      Quite a few tests use these weird contexts to trigger something else,
      so I had to suppress the warning in those.
      
      The 'haskeline' library has a few occurrences of the warning (which
      I think should be fixed), so I switched it off for that library in
      warnings.mk.
      
      The warning itself is done in TcValidity.check_class_pred.
      
      HOWEVER, when type inference fails we get a type error; and the error
      suppresses the (informative) warning.  So as things stand, the warning
      only happens when it doesn't cause a problem.  Not sure what to do
      about this, but this patch takes us forward, I think.
      9421b0c7
  12. 20 Apr, 2016 2 commits
    • Simon Peyton Jones's avatar
      Define NameSet.intersectFVs · 871f684d
      Simon Peyton Jones authored
      I want it for subsequent commits
      871f684d
    • Simon Peyton Jones's avatar
      Reduce use of instances in hs-boot files · 81aa3d1c
      Simon Peyton Jones authored
      Several things here
      
      * GHC no longer allows user-written Typeable instances,
        so remove them from hs-boot files.
      
      * Generally, reduce the use of instances in hs-boot files. They are
        hard to track.  Mainly this involves using pprType, pprKind etc
        instead of just ppr.  There were a lot of instances in hs-boot
        files that weren't needed at all.
      
      * Take TyThing out of Eq; it was used in exactly one place (in
        InteractiveEval), and equality is too big a hammer for that.
      81aa3d1c
  13. 14 Apr, 2016 1 commit
    • Joachim Breitner's avatar
      Add a final demand analyzer run right before TidyCore · f4fd98c7
      Joachim Breitner authored
      in order to have precise used-once information in the exported
      strictness signatures, as well as precise used-once information on
      thunks. This avoids the bad effects of #11731.
      
      The subsequent worker-wrapper pass is responsible for removing the
      demand environment part of the strictness signature. It does not run
      after the final demand analyzer pass, so remove this also in CoreTidy.
      
      The subsequent worker-wrapper pass is also responsible for removing
      used-once-information from the demands and strictness signatures, as
      these might not be preserved by the simplifier. This is _not_ done by
      CoreTidy, because we _do_ want this information, as produced by the last
      round of the demand analyzer, to be available to the code generator.
      
      Differential Revision: https://phabricator.haskell.org/D2073
      f4fd98c7
  14. 12 Apr, 2016 1 commit
  15. 10 Apr, 2016 1 commit
    • Jason Eisenberg's avatar
      Fix suggestions for unbound variables (#11680) · 470d4d5b
      Jason Eisenberg authored
      When the typechecker generates the error message for an out-of-scope
      variable, it now uses the GlobalRdrEnv with respect to which the
      variable is unbound, not the GlobalRdrEnv which is available at the time
      the error is reported.  Doing so ensures we do not provide suggestions
      which themselves are out-of-scope (because they are bound in a later
      inter-splice group).
      
      Nonetheless, we do note in the error message if an unambiguous, exact
      match to the out-of-scope variable is found in a later inter-splice
      group, and we specify where that match is not in scope.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, austin, bgamari
      
      Reviewed By: goldfire
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2000
      
      GHC Trac Issues: #11680
      470d4d5b
  16. 06 Apr, 2016 1 commit
    • Joachim Breitner's avatar
      Demand Analyzer: Do not set OneShot information (second try) · 0f58d348
      Joachim Breitner authored
      as suggested in ticket:11770#comment:1. This code was buggy
      (#11770), and the occurrence analyzer does the same job anyways.
      
      This also elaborates the notes in the occurrence analyzer accordingly.
      
      Previously, the worker/wrapper code would go through lengths to transfer
      the oneShot annotations from the original function to both the worker
      and the wrapper. We now simply transfer the demand on the worker, and
      let the subsequent occurrence analyzer push this onto the lambda
      binders.
      
      This also requires the occurrence analyzer to do this more reliably.
      Previously, it would not hand out OneShot annotatoins to things that
      would not `certainly_inline` (and it might not have mattered, as the
      Demand Analysis might have handed out the annotations). Now we hand out
      one-shot annotations unconditionally.
      
      Differential Revision: https://phabricator.haskell.org/D2085
      0f58d348
  17. 02 Apr, 2016 1 commit
    • Rik Steenkamp's avatar
      Improve printing of pattern synonym types · 72bd7f7b
      Rik Steenkamp authored
      Add the function `pprPatSynType :: PatSyn -> SDoc` for printing pattern
      synonym types, and remove the ambiguous `patSynType` function. Also,
      the types in a `PatSyn` are now tidy.
      
      Haddock submodule updated to reflect the removal of `patSynType` by
      mpickering.
      
      Fixes: #11213.
      
      Reviewers: goldfire, simonpj, austin, mpickering, bgamari
      
      Reviewed By: simonpj, mpickering
      
      Subscribers: bollmann, simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1896
      
      GHC Trac Issues: #11213
      72bd7f7b
  18. 31 Mar, 2016 2 commits
  19. 29 Mar, 2016 2 commits
  20. 25 Mar, 2016 1 commit
    • Simon Peyton Jones's avatar
      A raft of comments about TyBinders · 067335a6
      Simon Peyton Jones authored
      I had a conversation with Richard about TyBinders
      and VisibilityFlags.  This patch adds a lot of comments
      to explain what is going on.  I feel much more secure now.
      
      Richard please check.
      067335a6
  21. 24 Mar, 2016 2 commits
    • Simon Peyton Jones's avatar
      Tidy up handling of coercion variables · cb08f8da
      Simon Peyton Jones authored
      * Comments to explain that a CoVar, whose IdInfo is CoVarId,
        is always unlifted (but may be nominal or representational role)
      
        And TyCoRep.isCoercionType picks out only those unlifted
        types, NOT the lifted versions
      
      * Introduce Var.NcId for non-co-var Ids
        with predicate isNonCoVarId
      
      * Add assertions in CoreSubst that the Id env is only
        used for NcIds
      
      * Fix lurking bug in CSE which extended the
        CoreSubst Id env with a CoVar
      
      * Fix two bugs in Specialise.spec_call, which wrongly treated
        CoVars like NcIds
          - needed a varToCoreExpr in one place
          - needed extendSubst not extendIdSubst in another
        This was the root cause of Trac #11644
      
      Minor refactoring
      
      * Eliminate unused mkDerivedLocalCoVarM, mkUserLocalCoVar
      * Small refactor in mkSysLocalOrCoVar
      cb08f8da
    • Rik Steenkamp's avatar
      Add `PatSynSigSkol` and modify `PatSynCtxt` · 997312b0
      Rik Steenkamp authored
      As the type of a pattern synonym cannot in general be represented by a
      value of type Type, we cannot use a value `SigSkol (PatSynCtxt n) (Check
      ty)` to represent the signature of a pattern synonym (this causes
      incorrect signatures to be printed in error messages). Therefore we now
      represent it by a value `PatSynSigSkol n` (instead of incorrect
      signatures we simply print no explicit signature).
      
      Furthermore, we rename `PatSynCtxt` to `PatSynBuilderCtxt`, and use
      `SigSkol (PatSynBuilderCtxt n) (Check ty)` to represent the type of a
      bidirectional pattern synonym when used in an expression context.
      Before, this type was represented by a value `SigSkol (PatSynCtxt n)
      (Check ty)`, which caused incorrect error messages.
      
      Also, in `mk_dict_err` of `typecheck\TcErrors.hs` we now distinguish
      between all enclosing implications and "useful" enclosing implications,
      for better error messages concerning pattern synonyms. See `Note [Useful
      implications]`.
      
      See the Phabricator page for examples.
      
      Reviewers: mpickering, goldfire, simonpj, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1967
      
      GHC Trac Issues: #11667
      997312b0
  22. 21 Mar, 2016 2 commits
    • eir@cis.upenn.edu's avatar
      Track specified/invisible more carefully. · 35e93797
      eir@cis.upenn.edu authored
      In particular, this allows correct tracking of specified/invisible
      for variables in Haskell98 data constructors and in pattern synonyms.
      GADT-syntax constructors are harder, and are left until #11721.
      
      This was all inspired by Simon's comments to my fix for #11512,
      which this subsumes.
      
      Test case: ghci/scripts/TypeAppData
      
      [skip ci]  (The test case fails because of an unrelated problem
      fixed in the next commit.)
      35e93797
    • niteria's avatar
      Remove unnecessary Ord instance for ConLike · 2cb55772
      niteria authored
      The Ord instance for ConLike uses Unique order which is bad for
      determinism. Fortunately it's not used, so we can just delete it.
      The is part of the effort to make Unique comparisons explicit.
      
      Test Plan: ./validate
      
      Reviewers: austin, simonmar, bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2018
      
      GHC Trac Issues: #4012
      2cb55772
  23. 17 Mar, 2016 1 commit
  24. 11 Mar, 2016 1 commit
  25. 09 Mar, 2016 1 commit
    • Simon Peyton Jones's avatar
      Fix the implementation of lazyId · 4c3a0a4a
      Simon Peyton Jones authored
      'lazy' was doing part of its job, but not all!  In particular,
      an application
        f (lazy e)
      where f is strict, was still being compiled using call-by-value in
      CorePrep.  This defeated the purpose of defining catch as
         catch a b = catch# (lazy a) b
      See Trac #11555, and Neil Mitchell's test case in comment:14
      
      This patch makes 'lazy' behave properly. I updated Note [lazyId magic]
      in MkId, but all the action is in CorePrep.
      
      I can't say I really like this, but it does the job.
      4c3a0a4a
  26. 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
  27. 23 Feb, 2016 1 commit