1. 12 Feb, 2020 3 commits
  2. 11 Feb, 2020 5 commits
    • Matthew Pickering's avatar
      TemplateHaskellQuotes: Allow nested splices · 82023524
      Matthew Pickering authored
      There is no issue with nested splices as they do not require any compile
      time code execution. All execution is delayed until the top-level
      splice.
      82023524
    • Simon Peyton Jones's avatar
      Notes only: telescopes · d8d73d77
      Simon Peyton Jones authored
      This documentation-only patch fixes #17793
      d8d73d77
    • Sylvain Henry's avatar
      Add arithmetic exception primops (#14664) · aba51b65
      Sylvain Henry authored
      aba51b65
    • Richard Eisenberg's avatar
      Do not create nested quantified constraints · de32beff
      Richard Eisenberg authored
      Previously, we would accidentally make constraints like
      forall a. C a => forall b. D b => E a b c as we traversed
      superclasses. No longer!
      
      This patch also expands Note [Eagerly expand given superclasses]
      to work over quantified constraints; necessary for T16502b.
      
      Close #17202 and #16502.
      
      test cases: typecheck/should_compile/T{17202,16502{,b}}
      de32beff
    • Sebastian Graf's avatar
      Fix long distance info for record updates · f3e737bb
      Sebastian Graf authored
      For record updates where the `record_expr` is a variable, as in #17783:
      
      ```hs
      data PartialRec = No
                      | Yes { a :: Int, b :: Bool }
      update No = No
      update r@(Yes {}) = r { b = False }
      ```
      
      We should make use of long distance info in
      `-Wincomplete-record-updates` checking. But the call to `matchWrapper`
      in the `RecUpd` case didn't specify a scrutinee expression, which would
      correspond to the `record_expr` `r` here. That is fixed now.
      
      Fixes #17783.
      f3e737bb
  3. 09 Feb, 2020 3 commits
    • Andreas Klebinger's avatar
      Fix -ddump-stg-final. · b2e18e26
      Andreas Klebinger authored
      Once again make sure this dumps the STG used for codegen.
      b2e18e26
    • Roland Senn's avatar
      Fix #14628: Panic (No skolem Info) in GHCi · 82f9be8c
      Roland Senn authored
      This patch implements the [sugggestion from Simon (PJ)](ghc/ghc#14628 (comment 146559)):
      - Make `TcErrors.getSkolemInfo` return a `SkolemInfo` rather than an `Implication`.
      - If `getSkolemInfo` gets `RuntimeUnk`s, just return a new data constructor in `SkolemInfo`, called `RuntimeUnkSkol`.
      - In `TcErrors.pprSkols` print something sensible for a `RuntimeUnkSkol`.
      
      The `getSkolemInfo` function paniced while formating suggestions to add type annotations (subfunction `suggestAddSig`)
      to a *"Couldn't match type ‘x’ with ‘y’"* error message.
      The `getSkolemInfo` function didn't find any Implication value and paniced.
      With this patch the `getSkolemInfo` function does no longer panic, if it finds `RuntimeUnkSkol`s.
      
      As the panic occured while processing an error message, we don't need to implement any new error message!
      82f9be8c
    • Arnaud Spiwack's avatar
      Fix an outdated note link · a906595f
      Arnaud Spiwack authored
      This link appears to have been forgotten in
      0dad81ca .
      a906595f
  4. 08 Feb, 2020 8 commits
  5. 06 Feb, 2020 8 commits
    • Simon Peyton Jones's avatar
      Comments only · 7c122851
      Simon Peyton Jones authored
      7c122851
    • Simon Peyton Jones's avatar
      Use foldTyCo for exactTyCoVarsOfType · 5541b87c
      Simon Peyton Jones authored
      This entailed
      
      * Adding a tcf_view field to TyCoFolder
      
      * Moving exactTyCoVarsOtType to TcType.  It properly belongs
        there, since only the typechecker calls this function. But
        it also means that we can "see" and inline tcView.
      
      Metric Decrease:
        T14683
      5541b87c
    • Simon Peyton Jones's avatar
      Use foldTyCo for coVarsOfType · 9ca5c88e
      Simon Peyton Jones authored
      9ca5c88e
    • Simon Peyton Jones's avatar
      Simplify closeOverKinds · 0e59afd6
      Simon Peyton Jones authored
      0e59afd6
    • Simon Peyton Jones's avatar
      Use foldTyCo for noFreeVarsOfType · 01a1f4fb
      Simon Peyton Jones authored
      01a1f4fb
    • Simon Peyton Jones's avatar
      Reform the free variable finders for types · ed2f0e5c
      Simon Peyton Jones authored
      This patch delivers on (much of) #17509.
      
      * Introduces the shallow vs deep free variable distinction
      
      * Introduce TyCoRep.foldType,
          foldType :: Monoid a => TyCoFolder env a
                               -> env -> Type -> a
        and use it in the free variable finders.
      
      * Substitution in TyCoSubst
         * ASSERTs are on for checkValidSubst
         * checkValidSubst uses shallowTyCoVarsOfTypes etc
      
      Quite a few things still to do
      
      * We could use foldType in lots of other places
      
      * We could use mapType for substitution.  (Check that we get
        good code!)
      
      * Some (but not yet all) clients of substitution can now
        save time by using shallowTyCoVarsOfTypes
      
      * All calls to tyCoVarsOfTypes should be inspected; most of
        them should be shallow.  Maybe.
      
      * Currently shallowTyCoVarsOfTypes still returns
        unification variables, but not CoVarHoles.
        Reason: we need to return unification variables
        in some of the calls in TcSimplify, eg when promoting.
      
      * We should do the same thing for tyCoFVsOfTypes, which is
        currently unchanged.
      
      * tyCoFVsOfTypes returns CoVarHoles, because of the
        use in TcSimplify.mkResidualConstraints.  See
        Note [Emitting the residual implication in simplifyInfer]
      
      * #17509 talks about "relevant" variables too.
      ed2f0e5c
    • Ben Gamari's avatar
      Move closeOverKinds and friends to TyCoFVs · c4e6b35d
      Ben Gamari authored
      c4e6b35d
    • Ben Gamari's avatar
      VarSet: Introduce nonDetFoldVarSet · 29b72c00
      Ben Gamari authored
      29b72c00
  6. 05 Feb, 2020 2 commits
    • Ömer Sinan Ağacan's avatar
      Remove CafInfo-related code from STG lambda lift pass · 9c89a48d
      Ömer Sinan Ağacan authored
      After c846618a we don't have accurate CafInfos for Ids in the current
      module and we're free to introduce new CAFFY or non-CAFFY bindings or
      change CafInfos of existing binders; so no we no longer need to
      maintain CafInfos in Core or STG passes.
      9c89a48d
    • Sebastian Graf's avatar
      PmCheck: Record type constraints arising from existentials in `PmCoreCt`s · c90eca55
      Sebastian Graf authored
      In #17703 (a follow-up of !2192), we established that contrary to my
      belief, type constraints arising from existentials in code like
      
      ```hs
      data Ex where Ex :: a -> Ex
      f _ | let x = Ex @Int 15 = case x of Ex -> ...
      ```
      
      are in fact useful.
      
      This commit makes a number of refactorings and improvements to comments,
      but fundamentally changes `addCoreCt.core_expr` to record the type
      constraint `a ~ Int` in addition to `x ~ Ex @a y` and `y ~ 15`.
      
      Fixes #17703.
      c90eca55
  7. 04 Feb, 2020 3 commits
    • John Ericson's avatar
      Delete some superfluous helper functions in HscMain · eb629fab
      John Ericson authored
      The driver code is some of the nastiest in GHC, and I am worried about
      being able to untangle all the tech debt. In `HscMain` we have a number
      of helpers which are either not-used or little used. I delete them so we
      can reduce cognative load, distilling the essential complexity away from
      the cruft.
      eb629fab
    • John Ericson's avatar
      Refactor HscMain.finish · 5e63d9c0
      John Ericson authored
      I found the old control flow a bit hard to follow; I rewrote it to first
      decide whether to desugar, and then use that choice when computing
      whether to simplify / what sort of interface file to write.
      
      I hope eventually we will always write post-tc interface files, which
      will make the logic of this function even simpler, and continue the
      thrust of this refactor.
      5e63d9c0
    • John Ericson's avatar
      Fix docs for FrontendResult · 54dfa94a
      John Ericson authored
      Other variant was removed in ac1a3793
      but docs were no changed.
      54dfa94a
  8. 01 Feb, 2020 3 commits
    • Simon Peyton Jones's avatar
      Fix scoping of TyCon binders in TcTyClsDecls · 913287a0
      Simon Peyton Jones authored
      This patch fixes #17566 by refactoring the way we decide the final
      identity of the tyvars in the TyCons of a possibly-recursive nest
      of type and class decls, possibly with associated types.
      
      It's all laid out in
        Note [Swizzling the tyvars before generaliseTcTyCon]
      
      Main changes:
      
      * We have to generalise each decl (with its associated types)
        all at once: TcTyClsDecls.generaliseTyClDecl
      
      * The main new work is done in TcTyClsDecls.swizzleTcTyConBndrs
      
      * The mysterious TcHsSyn.zonkRecTyVarBndrs dies altogether
      
      Other smaller things:
      
      * A little refactoring, moving bindTyClTyVars from tcTyClDecl1
        to tcDataDefn, tcSynRhs, etc.  Clearer, reduces the number of
        parameters
      
      * Reduce the amount of swizzling required.
        Specifically, bindExplicitTKBndrs_Q_Tv doesn't need
          to clone a new Name for the TyVarTv, and not
          cloning means that in the vasly common case,
          swizzleTyConBndrs is a no-op
      
        In detail:
          Rename newTyVarTyVar --> cloneTyVarTyVar
          Add newTyVarTyTyVar that doesn't clone
          Use the non-cloning newTyVarTyVar in
             bindExplicitTKBndrs_Q_Tv
             Rename newFlexiKindedTyVarTyVar
                 --> cloneFlexiKindedTyVarTyVar
      
      * Define new utility function and use it
           HsDecls.familyDeclName ::
              FamilyDecl (GhcPass p) -> IdP (GhcPass p)
      
      Updates haddock submodule.
      913287a0
    • Simon Peyton Jones's avatar
      Improve pretty-printing for TyConBinders · cd110423
      Simon Peyton Jones authored
      In particular, show their kinds.
      cd110423
    • Simon Peyton Jones's avatar
      Improve skolemisation · bef704b6
      Simon Peyton Jones authored
      This patch avoids skolemiseUnboundMetaTyVar making
      up a fresh Name when it doesn't need to.
      
      See Note [Skolemising and identity]
      
      Improves error messsages for partial type signatures.
      bef704b6
  9. 31 Jan, 2020 5 commits
    • Andreas Klebinger's avatar
      A few optimizations in STG and Cmm parts: · 2a87a565
      Andreas Klebinger authored
      (Guided by the profiler output)
      
      - Add a few bang patterns, INLINABLE annotations, and a seqList in a few
        places in Cmm and STG parts.
      
      - Do not add external variables as dependencies in STG dependency
        analysis (GHC.Stg.DepAnal).
      2a87a565
    • Ömer Sinan Ağacan's avatar
      Do CafInfo/SRT analysis in Cmm · c846618a
      Ömer Sinan Ağacan authored
      This patch removes all CafInfo predictions and various hacks to preserve
      predicted CafInfos from the compiler and assigns final CafInfos to
      interface Ids after code generation. SRT analysis is extended to support
      static data, and Cmm generator is modified to allow generating
      static_link fields after SRT analysis.
      
      This also fixes `-fcatch-bottoms`, which introduces error calls in case
      expressions in CorePrep, which runs *after* CoreTidy (which is where we
      decide on CafInfos) and turns previously non-CAFFY things into CAFFY.
      
      Fixes #17648
      Fixes #9718
      
      Evaluation
      ==========
      
      NoFib
      -----
      
      Boot with: `make boot mode=fast`
      Run: `make mode=fast EXTRA_RUNTEST_OPTS="-cachegrind" NoFibRuns=1`
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs    Instrs     Reads    Writes
      --------------------------------------------------------------------------------
                   CS          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  CSD          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                   FS          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                    S          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                   VS          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  VSD          -0.0%      0.0%     -0.0%     -0.0%     -0.5%
                  VSM          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 anna          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
                 ansi          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 atom          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               awards          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               banner          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
           bernouilli          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         binary-trees          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                boyer          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               boyer2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 bspt          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            cacheprof          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             calendar          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             cichelli          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              circsim          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             clausify          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
        comp_lab_zift          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             compress          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            compress2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
          constraints          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         cryptarithm1          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         cryptarithm2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  cse          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         digits-of-e1          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         digits-of-e2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               dom-lt          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                eliza          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                event          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
          exact-reals          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               exp3_8          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               expert          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
       fannkuch-redux          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                fasta          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  fem          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  fft          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 fft2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             fibheaps          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 fish          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                fluid          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
               fulsom          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               gamteb          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  gcd          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
          gen_regexps          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               genfft          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                   gg          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 grep          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               hidden          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  hpg          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
                  ida          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                infer          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              integer          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            integrate          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         k-nucleotide          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                kahan          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              knights          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               lambda          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
           last-piece          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 lcss          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 life          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 lift          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               linear          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
            listcompr          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             listcopy          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             maillist          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               mandel          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              mandel2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 mate          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              minimax          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              mkhprog          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
           multiplier          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               n-body          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             nucleic2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 para          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            paraffins          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               parser          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
              parstof          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
                  pic          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             pidigits          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                power          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               pretty          -0.0%      0.0%     -0.3%     -0.4%     -0.4%
               primes          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            primetest          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               prolog          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               puzzle          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               queens          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              reptile          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
      reverse-complem          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              rewrite          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 rfib          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  rsa          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  scc          -0.0%      0.0%     -0.3%     -0.5%     -0.4%
                sched          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  scs          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               simple          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
                solid          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              sorting          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
        spectral-norm          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               sphere          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
               symalg          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                  tak          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            transform          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             treejoin          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            typecheck          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
              veritas          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 wang          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
            wave4main          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         wheel-sieve1          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
         wheel-sieve2          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 x2n1          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
      --------------------------------------------------------------------------------
                  Min          -0.1%      0.0%     -0.3%     -0.5%     -0.5%
                  Max          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
       Geometric Mean          -0.0%     -0.0%     -0.0%     -0.0%     -0.0%
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs    Instrs     Reads    Writes
      --------------------------------------------------------------------------------
              circsim          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
          constraints          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             fibheaps          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
             gc_bench          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 hash          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                 lcss          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
                power          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
           spellcheck          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
      --------------------------------------------------------------------------------
                  Min          -0.1%      0.0%     -0.0%     -0.0%     -0.0%
                  Max          -0.0%      0.0%     -0.0%     -0.0%     -0.0%
       Geometric Mean          -0.0%     +0.0%     -0.0%     -0.0%     -0.0%
      
      Manual inspection of programs in testsuite/tests/programs
      ---------------------------------------------------------
      
      I built these programs with a bunch of dump flags and `-O` and compared
      STG, Cmm, and Asm dumps and file sizes.
      
      (Below the numbers in parenthesis show number of modules in the program)
      
      These programs have identical compiler (same .hi and .o sizes, STG, and
      Cmm and Asm dumps):
      
      - Queens (1), andre_monad (1), cholewo-eval (2), cvh_unboxing (3),
        andy_cherry (7), fun_insts (1), hs-boot (4), fast2haskell (2),
        jl_defaults (1), jq_readsPrec (1), jules_xref (1), jtod_circint (4),
        jules_xref2 (1), lennart_range (1), lex (1), life_space_leak (1),
        bargon-mangler-bug (7), record_upd (1), rittri (1), sanders_array (1),
        strict_anns (1), thurston-module-arith (2), okeefe_neural (1),
        joao-circular (6), 10queens (1)
      
      Programs with different compiler outputs:
      
      - jl_defaults (1): For some reason GHC HEAD marks a lot of top-level
        `[Int]` closures as CAFFY for no reason. With this patch we no longer
        make them CAFFY and generate less SRT entries. For some reason Main.o
        is slightly larger with this patch (1.3%) and the executable sizes are
        the same. (I'd expect both to be smaller)
      
      - launchbury (1): Same as jl_defaults: top-level `[Int]` closures marked
        as CAFFY for no reason. Similarly `Main.o` is 1.4% larger but the
        executable sizes are the same.
      
      - galois_raytrace (13): Differences are in the Parse module. There are a
        lot, but some of the changes are caused by the fact that for some
        reason (I think a bug) GHC HEAD marks the dictionary for `Functor
        Identity` as CAFFY. Parse.o is 0.4% larger, the executable size is the
        same.
      
      - north_array: We now generate less SRT entries because some of array
        primops used in this program like `NewArrayOp` get eliminated during
        Stg-to-Cmm and turn some CAFFY things into non-CAFFY. Main.o gets 24%
        larger (9224 bytes from 9000 bytes), executable sizes are the same.
      
      - seward-space-leak: Difference in this program is better shown by this
        smaller example:
      
            module Lib where
      
            data CDS
              = Case [CDS] [(Int, CDS)]
              | Call CDS CDS
      
            instance Eq CDS where
              Case sels1 rets1 == Case sels2 rets2 =
                  sels1 == sels2 && rets1 == rets2
              Call a1 b1 == Call a2 b2 =
                  a1 == a2 && b1 == b2
              _ == _ =
                  False
      
         In this program GHC HEAD builds a new SRT for the recursive group of
         `(==)`, `(/=)` and the dictionary closure. Then `/=` points to `==`
         in its SRT field, and `==` uses the SRT object as its SRT. With this
         patch we use the closure for `/=` as the SRT and add `==` there. Then
         `/=` gets an empty SRT field and `==` points to `/=` in its SRT
         field.
      
         This change looks fine to me.
      
         Main.o gets 0.07% larger, executable sizes are identical.
      
      head.hackage
      ------------
      
      head.hackage's CI script builds 428 packages from Hackage using this
      patch with no failures.
      
      Compiler performance
      --------------------
      
      The compiler perf tests report that the compiler allocates slightly more
      (worst case observed so far is 4%). However most programs in the test
      suite are small, single file programs. To benchmark compiler performance
      on something more realistic I build Cabal (the library, 236 modules)
      with different optimisation levels. For the "max residency" row I run
      GHC with `+RTS -s -A100k -i0 -h` for more accurate numbers. Other rows
      are generated with just `-s`. (This is because `-i0` causes running GC
      much more frequently and as a result "bytes copied" gets inflated by
      more than 25x in some cases)
      
      * -O0
      
      |                 | GHC HEAD       | This MR        | Diff   |
      | --------------- | -------------- | -------------- | ------ |
      | Bytes allocated | 54,413,350,872 | 54,701,099,464 | +0.52% |
      | Bytes copied    |  4,926,037,184 |  4,990,638,760 | +1.31% |
      | Max residency   |    421,225,624 |    424,324,264 | +0.73% |
      
      * -O1
      
      |                 | GHC HEAD        | This MR         | Diff   |
      | --------------- | --------------- | --------------- | ------ |
      | Bytes allocated | 245,849,209,992 | 246,562,088,672 | +0.28% |
      | Bytes copied    |  26,943,452,560 |  27,089,972,296 | +0.54% |
      | Max residency   |     982,643,440 |     991,663,432 | +0.91% |
      
      * -O2
      
      |                 | GHC HEAD        | This MR         | Diff   |
      | --------------- | --------------- | --------------- | ------ |
      | Bytes allocated | 291,044,511,408 | 291,863,910,912 | +0.28% |
      | Bytes copied    |  37,044,237,616 |  36,121,690,472 | -2.49% |
      | Max residency   |   1,071,600,328 |   1,086,396,256 | +1.38% |
      
      Extra compiler allocations
      --------------------------
      
      Runtime allocations of programs are as reported above (NoFib section).
      
      The compiler now allocates more than before. Main source of allocation
      in this patch compared to base commit is the new SRT algorithm
      (GHC.Cmm.Info.Build). Below is some of the extra work we do with this
      patch, numbers generated by profiled stage 2 compiler when building a
      pathological case (the test 'ManyConstructors') with '-O2':
      
      - We now sort the final STG for a module, which means traversing the
        entire program, generating free variable set for each top-level
        binding, doing SCC analysis, and re-ordering the program. In
        ManyConstructors this step allocates 97,889,952 bytes.
      
      - We now do SRT analysis on static data, which in a program like
        ManyConstructors causes analysing 10,000 bindings that we would
        previously just skip. This step allocates 70,898,352 bytes.
      
      - We now maintain an SRT map for the entire module as we compile Cmm
        groups:
      
            data ModuleSRTInfo = ModuleSRTInfo
              { ...
              , moduleSRTMap :: SRTMap
              }
      
         (SRTMap is just a strict Map from the 'containers' library)
      
         This map gets an entry for most bindings in a module (exceptions are
         THUNKs and CAFFY static functions). For ManyConstructors this map
         gets 50015 entries.
      
      - Once we're done with code generation we generate a NameSet from SRTMap
        for the non-CAFFY names in the current module. This set gets the same
        number of entries as the SRTMap.
      
      - Finally we update CafInfos in ModDetails for the non-CAFFY Ids, using
        the NameSet generated in the previous step. This usually does the
        least amount of allocation among the work listed here.
      
      Only place with this patch where we do less work in the CAF analysis in
      the tidying pass (CoreTidy). However that doesn't save us much, as the
      pass still needs to traverse the whole program and update IdInfos for
      other reasons. Only thing we don't here do is the `hasCafRefs` pass over
      the RHS of bindings, which is a stateless pass that returns a boolean
      value, so it doesn't allocate much.
      
      (Metric changes blow are all increased allocations)
      
      Metric changes
      --------------
      
      Metric Increase:
          ManyAlternatives
          ManyConstructors
          T13035
          T14683
          T1969
          T9961
      c846618a
    • Ben Gamari's avatar
      rename: Eliminate usage of mkVarOccUnique · 942c7148
      Ben Gamari authored
      Replacing it with `newSysName`. Fixes #17061.
      942c7148
    • Sylvain Henry's avatar
      Refactor package related code · 29c701c1
      Sylvain Henry authored
      The package terminology is a bit of a mess. Cabal packages contain
      components. Instances of these components when built with some
      flags/options/dependencies are called units. Units are registered into
      package databases and their metadata are called PackageConfig.
      
      GHC only knows about package databases containing units. It is a sad
      mismatch not fixed by this patch (we would have to rename parameters
      such as `package-id <unit-id>` which would affect users).
      
      This patch however fixes the following internal names:
      
      - Renames PackageConfig into UnitInfo.
      - Rename systemPackageConfig into globalPackageDatabase[Path]
      - Rename PkgConfXX into PkgDbXX
      - Rename pkgIdMap into unitIdMap
      - Rename ModuleToPkgDbAll into ModuleNameProvidersMap
      - Rename lookupPackage into lookupUnit
      - Add comments on DynFlags package related fields
      
      It also introduces a new `PackageDatabase` datatype instead of
      explicitly passing the following tuple: `(FilePath,[PackageConfig])`.
      
      The `pkgDatabase` field in `DynFlags` now contains the unit info for
      each unit of each package database exactly as they have been read from
      disk. Previously the command-line flag `-distrust-all-packages` would
      modify these unit info. Now this flag only affects the "dynamic"
      consolidated package state found in `pkgState` field. It makes sense
      because `initPackages` could be called first with this
      `distrust-all-packages` flag set and then again (using ghc-api) without
      and it should work (package databases are not read again from disk when
      `initPackages` is called the second time).
      
      Bump haddock submodule
      29c701c1
    • Sylvain Henry's avatar
      Call `interpretPackageEnv` from `setSessionDynFlags` · bf38a20e
      Sylvain Henry authored
      interpretPackageEnv modifies the flags by reading the dreaded package
      environments. It is much less surprising to call it from
      `setSessionDynFlags` instead of reading package environments as a
      side-effect of `initPackages`.
      bf38a20e