1. 17 Dec, 2015 1 commit
    • Simon Marlow's avatar
      Remote GHCi, -fexternal-interpreter · 4905b83a
      Simon Marlow authored
      Summary:
      (Apologies for the size of this patch, I couldn't make a smaller one
      that was validate-clean and also made sense independently)
      
      (Some of this code is derived from GHCJS.)
      
      This commit adds support for running interpreted code (for GHCi and
      TemplateHaskell) in a separate process.  The functionality is
      experimental, so for now it is off by default and enabled by the flag
      -fexternal-interpreter.
      
      Reaosns we want this:
      
      * compiling Template Haskell code with -prof does not require
        building the code without -prof first
      
      * when GHC itself is profiled, it can interpret unprofiled code, and
        the same applies to dynamic linking.  We would no longer need to
        force -dynamic-too with TemplateHaskell, and we can load ordinary
        objects into a dynamically-linked GHCi (and vice versa).
      
      * An unprofiled GHCi can load and run profiled code, which means it
        can use the stack-trace functionality provided by profiling without
        taking the performance hit on the compiler that profiling would
        entail.
      
      Amongst other things; see
      https://ghc.haskell.org/trac/ghc/wiki/RemoteGHCi for more details.
      
      Notes on the implementation are in Note [Remote GHCi] in the new
      module compiler/ghci/GHCi.hs.  It probably needs more documenting,
      feel free to suggest things I could elaborate on.
      
      Things that are not currently implemented for -fexternal-interpreter:
      
      * The GHCi debugger
      * :set prog, :set args in GHCi
      * `recover` in Template Haskell
      * Redirecting stdin/stdout for the external process
      
      These are all doable, I just wanted to get to a working validate-clean
      patch first.
      
      I also haven't done any benchmarking yet.  I expect there to be slight hit
      to link times for byte code and some penalty due to having to
      serialize/deserialize TH syntax, but I don't expect it to be a serious
      problem.  There's also lots of low-hanging fruit in the byte code
      generator/linker that we could exploit to speed things up.
      
      Test Plan:
      * validate
      * I've run parts of the test suite with
      EXTRA_HC_OPTS=-fexternal-interpreter, notably tests/ghci and tests/th.
      There are a few failures due to the things not currently implemented
      (see above).
      
      Reviewers: simonpj, goldfire, ezyang, austin, alanz, hvr, niteria, bgamari, gibiansky, luite
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1562
      4905b83a
  2. 16 Dec, 2015 1 commit
  3. 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
  4. 03 Dec, 2015 1 commit
    • Georgios Karachalias's avatar
      Major Overhaul of Pattern Match Checking (Fixes #595) · 8a506104
      Georgios Karachalias authored
      This patch adresses several problems concerned with exhaustiveness and
      redundancy checking of pattern matching. The list of improvements includes:
      
      * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.).
        This fixes #4139, #3927, #8970 and other related tickets.
      
      * Making the check laziness-aware. Cases that are overlapped but affect
        evaluation are issued now with "Patterns have inaccessible right hand side".
        Additionally, "Patterns are overlapped" is now replaced by "Patterns are
        redundant".
      
      * Improved messages for literals. This addresses tickets #5724, #2204, etc.
      
      * Improved reasoning concerning cases where simple and overloaded
        patterns are matched (See #322).
      
      * Substantially improved reasoning for pattern guards. Addresses #3078.
      
      * OverloadedLists extension does not break exhaustiveness checking anymore
        (addresses #9951). Note that in general this cannot be handled but if we know
        that an argument has type '[a]', we treat it as a list since, the instance of
        'IsList' gives the identity for both 'fromList' and 'toList'. If the type is
        not clear or is not the list type, then the check cannot do much still. I am
        a bit concerned about OverlappingInstances though, since one may override the
        '[a]' instance with e.g. an '[Int]' instance that is not the identity.
      
      * Improved reasoning for nested pattern matching (partial solution). Now we
        propagate type and (some) term constraints deeper when checking, so we can
        detect more inconsistencies. For example, this is needed for #4139.
      
      I am still not satisfied with several things but I would like to address at
      least the following before the next release:
          Term constraints are too many and not printed for non-exhaustive matches
      (with the exception of literals). This sometimes results in two identical (in
      appearance) uncovered warnings. Unless we actually show their difference, I
      would like to have a single warning.
      8a506104
  5. 21 Nov, 2015 2 commits
    • niteria's avatar
      Create a deterministic version of tyVarsOfType · 2325bd4e
      niteria authored
      I've run into situations where I need deterministic `tyVarsOfType` and
      this implementation achieves that and also brings an algorithmic
      improvement.  Union of two `VarSet`s takes linear time the size of the
      sets and in the worst case we can have `n` unions of sets of sizes
      `(n-1, 1), (n-2, 1)...` making it quadratic.
      
      One reason why we need deterministic `tyVarsOfType` is in `abstractVars`
      in `SetLevels`. When we abstract type variables when floating we want
      them to be abstracted in deterministic order.
      
      Test Plan: harbormaster
      
      Reviewers: simonpj, goldfire, austin, hvr, simonmar, bgamari
      
      Reviewed By: simonmar
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1468
      
      GHC Trac Issues: #4012
      2325bd4e
    • niteria's avatar
      Add DVarSet - a deterministic set of Vars · 6664ab83
      niteria authored
      This implements `DVarSet`, a deterministic set of Vars, with an
      interface very similar to `VarSet` with a couple of functions missing.
      
      I will need this in changes that follow, one of them will be about
      changing the type of the set of Vars that `RuleInfo` holds to make the
      free variable computation deterministic.
      
      Test Plan:
      ./validate
      I can add new tests if anyone wants me to.
      
      Reviewers: simonpj, simonmar, austin, bgamari
      
      Reviewed By: simonmar, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1487
      
      GHC Trac Issues: #4012
      6664ab83
  6. 11 Nov, 2015 1 commit
    • Sylvain HENRY's avatar
      Systools: read ELF section without calling readelf · 109d7ce8
      Sylvain HENRY authored
      This patch tackles two issues:
      
      1) GHC stores a "link info" string into a ELF section. Initially a
      section with type "note" was used but GHC didn't follow the ELF
      specification which specifies a record-based format for these sections.
      With D1375 we switched to a "progbits" section type for which there
      isn't any format constraint. This is an issue for D1242 which use GCC's
      --gc-sections which collects "unused" sections, such as our section
      containing link info... In this patch, we fall back to a section with
      type "note" but we respect the specified format.
      
      2) Reading back the ELF section was done by parsing the result of a
      call to "readelf". Calling readelf is problematic because the program
      may not be available or it may be renamed on some platforms (see
      D1326). Moreover we have no garanty that its output layout will stay
      the same in future releases of readelf. Finally we would need to fix
      the parsing to support  "note" sections because of 1. Instead, this
      patch proposes to use Data.Binary.Get to directly read the "link info"
      note into its section. ELF has a specification, hence it should work on
      every conforming platform.
      
      This patch "reverts" D1375, hence it supersedes D1432. It makes D1326
      not necessary anymore.
      
      Test Plan:
      - recomp011 should pass (test that relinking is avoided when both "link
      info" match)
      - we should add a test for ELF objects with more than 0xff00 sections
      => added test "recomp015"
      - we should check that GAS generates 32-bit words with .int on every
      supported platform using ELF (or find a place where this is
      documented). harbomaster and I (@hsyl20) only tested on x86-64. On
      platforms where it is not true, it should make recomp011 fail. =>
      tested to work on Linux/amd64, Solaris/i386 and OpenBSD/amd64
      
      Reviewers: olsner, ony, thomie, kgardas, austin, bgamari
      
      Reviewed By: thomie, bgamari
      
      Subscribers: kgardas, rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1381
      
      GHC Trac Issues: #10974, #11022
      109d7ce8
  7. 02 Nov, 2015 1 commit
  8. 01 Nov, 2015 1 commit
    • Herbert Valerio Riedel's avatar
      Update process submodule · de8443c1
      Herbert Valerio Riedel authored
      This is needed to prepare for #11026 as this update
      relaxes the upper bounds on `base` to allow for `base-4.9.0.0`
      
      This also needs to relax a few upper bounds on process in some cabal files
      
      (there will be another process submodule update soon, as a major
      version bump of process' version is still pending)
      de8443c1
  9. 30 Oct, 2015 2 commits
    • niteria's avatar
      Make type-class dictionary let binds deterministic · a5cb27f3
      niteria authored
      When generating dictionary let binds in dsTcEvBinds we may
      end up generating them in arbitrary order according to Unique order.
      
      Consider:
      
      ```
      let $dEq = GHC.Classes.$fEqInt in
      let $$dNum = GHC.Num.$fNumInt in ...
      ```
      
      vs
      
      ```
      let $dNum = GHC.Num.$fNumInt in
      let $dEq = GHC.Classes.$fEqInt in ...
      ```
      
      The way this change fixes it is by using `UniqDFM` - a type of
      deterministic finite maps of things keyed on `Unique`s. This way when
      you pull out evidence variables corresponding to type-class dictionaries
      they are in deterministic order.
      
      Currently it's the order of insertion and the way it's implemented is by
      tagging the values with the time of insertion.
      
      Test Plan:
      I've added a new test case to reproduce the issue.
      ./validate
      
      Reviewers: ezyang, simonmar, austin, simonpj, bgamari
      
      Reviewed By: simonmar, simonpj, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1396
      
      GHC Trac Issues: #4012
      a5cb27f3
    • Ben Gamari's avatar
      Generate Typeable info at definition sites · 91c6b1f5
      Ben Gamari authored
      This is the second attempt at merging D757.
      
      This patch implements the idea floated in Trac #9858, namely that we
      should generate type-representation information at the data type
      declaration site, rather than when solving a Typeable constraint.
      
      However, this turned out quite a bit harder than I expected. I still
      think it's the right thing to do, and it's done now, but it was quite
      a struggle.
      
      See particularly
      
       * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
       * Note [The overall promotion story] in DataCon (clarifies existing
      stuff)
      
      The most painful bit was that to generate Typeable instances (ie
      TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
      etc:
      
       * We need to have enough data types around to *define* a TyCon
       * Many of these types are wired-in
      
      Also, to minimise the code generated for each data type, I wanted to
      generate pure data, not CAFs with unpackCString# stuff floating about.
      
      Performance
      ~~~~~~~~~~~
      Three perf/compiler tests start to allocate quite a bit more. This isn't
      surprising, because they all allocate zillions of data types, with
      practically no other code, esp. T1969
      
       * T1969:    GHC allocates 19% more
       * T4801:    GHC allocates 13% more
       * T5321FD:  GHC allocates 13% more
       * T9675:    GHC allocates 11% more
       * T783:     GHC allocates 11% more
       * T5642:    GHC allocates 10% more
      
      I'm treating this as acceptable. The payoff comes in Typeable-heavy
      code.
      
      Remaining to do
      ~~~~~~~~~~~~~~~
      
       * I think that "TyCon" and "Module" are over-generic names to use for
         the runtime type representations used in GHC.Typeable. Better might
      be
         "TrTyCon" and "TrModule". But I have not yet done this
      
       * Add more info the the "TyCon" e.g. source location where it was
         defined
      
       * Use the new "Module" type to help with Trac Trac #10068
      
       * It would be possible to generate TyConRepName (ie Typeable
         instances) selectively rather than all the time. We'd need to persist
         the information in interface files. Lacking a motivating reason I
      have
         not done this, but it would not be difficult.
      
      Refactoring
      ~~~~~~~~~~~
      As is so often the case, I ended up refactoring more than I intended.
      In particular
      
       * In TyCon, a type *family* (whether type or data) is repesented by a
         FamilyTyCon
           * a algebraic data type (including data/newtype instances) is
             represented by AlgTyCon This wasn't true before; a data family
             was represented as an AlgTyCon. There are some corresponding
             changes in IfaceSyn.
      
           * Also get rid of the (unhelpfully named) tyConParent.
      
       * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
         optionally promoted; and use it elsewhere in GHC.
      
       * Cleanup handling of knownKeyNames
      
       * Each TyCon, including promoted TyCons, contains its TyConRepName, if
         it has one. This is, in effect, the name of its Typeable instance.
      
      Updates haddock submodule
      
      Test Plan: Let Harbormaster validate
      
      Reviewers: austin, hvr, goldfire
      
      Subscribers: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1404
      
      GHC Trac Issues: #9858
      91c6b1f5
  10. 29 Oct, 2015 2 commits
    • Ben Gamari's avatar
      Revert "Generate Typeable info at definition sites" · bbaf76f9
      Ben Gamari authored
      This reverts commit bef2f03e.
      
      This merge was botched
      
      Also reverts haddock submodule.
      bbaf76f9
    • Ben Gamari's avatar
      Generate Typeable info at definition sites · bef2f03e
      Ben Gamari authored
      This patch implements the idea floated in Trac #9858, namely that we
      should generate type-representation information at the data type
      declaration site, rather than when solving a Typeable constraint.
      
      However, this turned out quite a bit harder than I expected. I still
      think it's the right thing to do, and it's done now, but it was quite
      a struggle.
      
      See particularly
      
       * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
       * Note [The overall promotion story] in DataCon (clarifies existing stuff)
      
      The most painful bit was that to generate Typeable instances (ie
      TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
      etc:
      
       * We need to have enough data types around to *define* a TyCon
       * Many of these types are wired-in
      
      Also, to minimise the code generated for each data type, I wanted to
      generate pure data, not CAFs with unpackCString# stuff floating about.
      
      Performance
      ~~~~~~~~~~~
      Three perf/compiler tests start to allocate quite a bit more. This isn't
      surprising, because they all allocate zillions of data types, with
      practically no other code, esp. T1969
      
       * T3294:   GHC allocates 110% more (filed #11030 to track this)
       * T1969:   GHC allocates 30% more
       * T4801:   GHC allocates 14% more
       * T5321FD: GHC allocates 13% more
       * T783:    GHC allocates 12% more
       * T9675:   GHC allocates 12% more
       * T5642:   GHC allocates 10% more
       * T9961:   GHC allocates 6% more
      
       * T9203:   Program allocates 54% less
      
      I'm treating this as acceptable. The payoff comes in Typeable-heavy
      code.
      
      Remaining to do
      ~~~~~~~~~~~~~~~
      
       * I think that "TyCon" and "Module" are over-generic names to use for
         the runtime type representations used in GHC.Typeable. Better might be
         "TrTyCon" and "TrModule". But I have not yet done this
      
       * Add more info the the "TyCon" e.g. source location where it was
         defined
      
       * Use the new "Module" type to help with Trac Trac #10068
      
       * It would be possible to generate TyConRepName (ie Typeable
         instances) selectively rather than all the time. We'd need to persist
         the information in interface files. Lacking a motivating reason I have
         not done this, but it would not be difficult.
      
      Refactoring
      ~~~~~~~~~~~
      As is so often the case, I ended up refactoring more than I intended.
      In particular
      
       * In TyCon, a type *family* (whether type or data) is repesented by a
         FamilyTyCon
           * a algebraic data type (including data/newtype instances) is
             represented by AlgTyCon This wasn't true before; a data family
             was represented as an AlgTyCon. There are some corresponding
             changes in IfaceSyn.
      
           * Also get rid of the (unhelpfully named) tyConParent.
      
       * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
         optionally promoted; and use it elsewhere in GHC.
      
       * Cleanup handling of knownKeyNames
      
       * Each TyCon, including promoted TyCons, contains its TyConRepName, if
         it has one. This is, in effect, the name of its Typeable instance.
      
      Requires update of the haddock submodule.
      
      Differential Revision: https://phabricator.haskell.org/D757
      bef2f03e
  11. 16 Oct, 2015 1 commit
    • Adam Gundry's avatar
      Implement DuplicateRecordFields · b1884b0e
      Adam Gundry authored
      This implements DuplicateRecordFields, the first part of the
      OverloadedRecordFields extension, as described at
      https://ghc.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/DuplicateRecordFields
      
      This includes fairly wide-ranging changes in order to allow multiple
      records within the same module to use the same field names.  Note that
      it does *not* allow record selector functions to be used if they are
      ambiguous, and it does not have any form of type-based disambiguation
      for selectors (but it does for updates). Subsequent parts will make
      overloading selectors possible using orthogonal extensions, as
      described on the wiki pages.  This part touches quite a lot of the
      codebase, and requires changes to several GHC API datatypes in order
      to distinguish between field labels (which may be overloaded) and
      selector function names (which are always unique).
      
      The Haddock submodule has been adapted to compile with the GHC API
      changes, but it will need further work to properly support modules
      that use the DuplicateRecordFields extension.
      
      Test Plan: New tests added in testsuite/tests/overloadedrecflds; these
      will be extended once the other parts are implemented.
      
      Reviewers: goldfire, bgamari, simonpj, austin
      
      Subscribers: sjcjoosten, haggholm, mpickering, bgamari, tibbe, thomie,
      goldfire
      
      Differential Revision: https://phabricator.haskell.org/D761
      b1884b0e
  12. 15 Oct, 2015 1 commit
  13. 13 Oct, 2015 1 commit
    • Ryan Scott's avatar
      Make dataToQa aware of Data instances which use functions to implement toConstr · d2f9972a
      Ryan Scott authored
      Trac #10796 exposes a way to make `template-haskell`'s `dataToQa` function
      freak out if using a `Data` instance that produces a `Constr` (by means of
      `toConstr`) using a function name instead of a data constructor name. While
      such `Data` instances are somewhat questionable, they are nevertheless present
      in popular libraries (e.g., `containers`), so we can at least make `dataToQa`
      aware of their existence.
      
      In order to properly distinguish strings which represent variables (as opposed
      to data constructors), it was necessary to move functionality from `Lexeme` (in
      `ghc`) to `GHC.Lexeme` in a new `ghc-boot` library (which was previously named
      `bin-package-db`).
      
      Reviewed By: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1313
      
      GHC Trac Issues: #10796
      d2f9972a
  14. 10 Oct, 2015 1 commit
  15. 24 Aug, 2015 1 commit
  16. 21 Aug, 2015 2 commits
    • thomie's avatar
      Refactor: delete most of the module FastTypes · 2f29ebbb
      thomie authored
      This reverses some of the work done in #1405, and goes back to the
      assumption that the bootstrap compiler understands GHC-haskell.
      
      In particular:
        * use MagicHash instead of _ILIT and _CLIT
        * pattern matching on I# if possible, instead of using iUnbox
          unnecessarily
        * use Int#/Char#/Addr# instead of the following type synonyms:
          - type FastInt   = Int#
          - type FastChar  = Char#
          - type FastPtr a = Addr#
        * inline the following functions:
          - iBox           = I#
          - cBox           = C#
          - fastChr        = chr#
          - fastOrd        = ord#
          - eqFastChar     = eqChar#
          - shiftLFastInt  = uncheckedIShiftL#
          - shiftR_FastInt = uncheckedIShiftRL#
          - shiftRLFastInt = uncheckedIShiftRL#
        * delete the following unused functions:
          - minFastInt
          - maxFastInt
          - uncheckedIShiftRA#
          - castFastPtr
          - panicDocFastInt and pprPanicFastInt
        * rename panicFastInt back to panic#
      
      These functions remain, since they actually do something:
        * iUnbox
        * bitAndFastInt
        * bitOrFastInt
      
      Test Plan: validate
      
      Reviewers: austin, bgamari
      
      Subscribers: rwbarton
      
      Differential Revision: https://phabricator.haskell.org/D1141
      
      GHC Trac Issues: #1405
      2f29ebbb
    • thomie's avatar
      Delete FastBool · 3452473b
      thomie authored
      This reverses some of the work done in Trac #1405, and assumes GHC is
      smart enough to do its own unboxing of booleans now.
      
      I would like to do some more performance measurements, but the code
      changes can be reviewed already.
      
      Test Plan:
      With a perf build:
      ./inplace/bin/ghc-stage2 nofib/spectral/simple/Main.hs -fforce-recomp
      +RTS -t --machine-readable
      
      before:
      ```
        [("bytes allocated", "1300744864")
        ,("num_GCs", "302")
        ,("average_bytes_used", "8811118")
        ,("max_bytes_used", "24477464")
        ,("num_byte_usage_samples", "9")
        ,("peak_megabytes_allocated", "64")
        ,("init_cpu_seconds", "0.001")
        ,("init_wall_seconds", "0.001")
        ,("mutator_cpu_seconds", "2.833")
        ,("mutator_wall_seconds", "4.283")
        ,("GC_cpu_seconds", "0.960")
        ,("GC_wall_seconds", "0.961")
        ]
      ```
      
      after:
      ```
        [("bytes allocated", "1301088064")
        ,("num_GCs", "310")
        ,("average_bytes_used", "8820253")
        ,("max_bytes_used", "24539904")
        ,("num_byte_usage_samples", "9")
        ,("peak_megabytes_allocated", "64")
        ,("init_cpu_seconds", "0.001")
        ,("init_wall_seconds", "0.001")
        ,("mutator_cpu_seconds", "2.876")
        ,("mutator_wall_seconds", "4.474")
        ,("GC_cpu_seconds", "0.965")
        ,("GC_wall_seconds", "0.979")
        ]
      ```
      
      CPU time seems to be up a bit, but I'm not sure. Unfortunately CPU time
      measurements are rather noisy.
      
      Reviewers: austin, bgamari, rwbarton
      
      Subscribers: nomeata
      
      Differential Revision: https://phabricator.haskell.org/D1143
      
      GHC Trac Issues: #1405
      3452473b
  17. 23 Jul, 2015 1 commit
    • Edward Z. Yang's avatar
      Library names, with Cabal submodule update · f9687caf
      Edward Z. Yang authored
      
      
      A library name is a package name, package version, and hash of the
      version names of all textual dependencies (i.e. packages which were included.) A library
      name is a coarse approximation of installed package IDs, which are suitable for
      inclusion in package keys (you don't want to put an IPID in a package key, since
      it means the key will change any time the source changes.)
      
          - We define ShPackageKey, which is the semantic object which
            is hashed into a PackageKey.  You can use 'newPackageKey'
            to hash a ShPackageKey to a PackageKey
      
          - Given a PackageKey, we can lookup its ShPackageKey with
            'lookupPackageKey'.  The way we can do this is by consulting
            the 'pkgKeyCache', which records a reverse mapping from
            every hash to the ShPackageKey.  This means that if you
            load in PackageKeys from external sources (e.g. interface
            files), you also need to load in a mapping of PackageKeys
            to their ShPackageKeys so we can populate the cache.
      
          - We define a 'LibraryName' which encapsulates the full
            depenency resolution that Cabal may have selected; this
            is opaque to GHC but can be used to distinguish different
            versions of a package.
      
          - Definite packages don't have an interesting PackageKey,
            so we rely on Cabal to pass them to us.
      
          - We can pretty-print package keys while displaying the
            instantiation, but it's not wired up to anything (e.g.
            the Outputable instance of PackageKey).
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: austin, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1056
      
      GHC Trac Issues: #10566
      f9687caf
  18. 16 Jul, 2015 2 commits
  19. 07 Jul, 2015 1 commit
  20. 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
  21. 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
  22. 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
  23. 11 May, 2015 1 commit
    • Edward Z. Yang's avatar
      Support stage 1 Template Haskell (non-quasi) quotes, fixes #10382. · f16ddcee
      Edward Z. Yang authored
      
      
      Summary:
      This commit adds stage 1 support for Template Haskell
      quoting, e.g. [| ... expr ... |], which is useful
      for authors of quasiquoter libraries that do not actually
      need splices.  The TemplateHaskell extension now does not
      unconditionally fail; it only fails if the renamer encounters
      a splice that it can't run.
      
      In order to make sure the referenced data structures
      are consistent, template-haskell is now a boot library.
      There are some minor BC changes to template-haskell to make it boot
      on GHC 7.8.
      
      Note for reviewer: big diff changes are simply code
      being moved out of an ifdef; there was no other substantive
      change to that code.
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, austin, goldfire
      
      Subscribers: bgamari, thomie
      
      Differential Revision: https://phabricator.haskell.org/D876
      
      GHC Trac Issues: #10382
      f16ddcee
  24. 09 May, 2015 2 commits
    • Edward Z. Yang's avatar
      Revert stage 1 template-haskell. This is a combination of 5 commits. · 5c459eef
      Edward Z. Yang authored
      Revert "Quick fix: drop base bound on template-haskell."
      
      This reverts commit 3c70ae03.
      
      Revert "Always do polymorphic typed quote check, c.f. #10384"
      
      This reverts commit 9a43b2c1.
      
      Revert "RnSplice's staging test should be applied for quotes in stage1."
      
      This reverts commit eb0ed403.
      
      Revert "Split off quotes/ from th/ for tests that can be done on stage1 compiler."
      
      This reverts commit 21c72e7d.
      
      Revert "Support stage 1 Template Haskell (non-quasi) quotes, fixes #10382."
      
      This reverts commit 28257cae.
      5c459eef
    • Edward Z. Yang's avatar
      Support stage 1 Template Haskell (non-quasi) quotes, fixes #10382. · 28257cae
      Edward Z. Yang authored
      
      
      Summary:
      This commit adds stage 1 support for Template Haskell
      quoting, e.g. [| ... expr ... |], which is useful
      for authors of quasiquoter libraries that do not actually
      need splices.  The TemplateHaskell extension now does not
      unconditionally fail; it only fails if the renamer encounters
      a splice that it can't run.
      
      In order to make sure the referenced data structures
      are consistent, template-haskell is now a boot library.
      
      In the following patches, there are:
      
          - A few extra safety checks which should be enabled
            in stage1
          - Separation of the th/ testsuite into quotes/ which
            can be run on stage1
      
      Note for reviewer: big diff changes are simply code
      being moved out of an ifdef; there was no other substantive
      change to that code.
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, austin, goldfire
      
      Subscribers: bgamari, thomie
      
      Differential Revision: https://phabricator.haskell.org/D876
      
      GHC Trac Issues: #10382
      28257cae
  25. 30 Mar, 2015 1 commit
    • Joachim Breitner's avatar
      Refactor the story around switches (#10137) · de1160be
      Joachim Breitner authored
      This re-implements the code generation for case expressions at the Stg →
      Cmm level, both for data type cases as well as for integral literal
      cases. (Cases on float are still treated as before).
      
      The goal is to allow for fancier strategies in implementing them, for a
      cleaner separation of the strategy from the gritty details of Cmm, and
      to run this later than the Common Block Optimization, allowing for one
      way to attack #10124. The new module CmmSwitch contains a number of
      notes explaining this changes. For example, it creates larger
      consecutive jump tables than the previous code, if possible.
      
      nofib shows little significant overall improvement of runtime. The
      rather large wobbling comes from changes in the code block order
      (see #8082, not much we can do about it). But the decrease in code size
      alone makes this worthwhile.
      
      ```
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
                  Min          -1.8%      0.0%     -6.1%     -6.1%     -2.9%
                  Max          -0.7%     +0.0%     +5.6%     +5.7%     +7.8%
       Geometric Mean          -1.4%     -0.0%     -0.3%     -0.3%     +0.0%
      ```
      
      Compilation time increases slightly:
      ```
              -1 s.d.                -----            -2.0%
              +1 s.d.                -----            +2.5%
              Average                -----            +0.3%
      ```
      
      The test case T783 regresses a lot, but it is the only one exhibiting
      any regression. The cause is the changed order of branches in an
      if-then-else tree, which makes the hoople data flow analysis traverse
      the blocks in a suboptimal order. Reverting that gets rid of this
      regression, but has a consistent, if only very small (+0.2%), negative
      effect on runtime. So I conclude that this test is an extreme outlier
      and no reason to change the code.
      
      Differential Revision: https://phabricator.haskell.org/D720
      de1160be
  26. 11 Mar, 2015 1 commit
  27. 17 Dec, 2014 1 commit
    • Peter Wortmann's avatar
      Generate DWARF info section · cc481ec8
      Peter Wortmann authored
      This is where we actually make GHC emit DWARF code. The info section
      contains all the general meta information bits as well as an entry for
      every block of native code.
      
      Notes:
      
      * We need quite a few new labels in order to properly address starts
        and ends of blocks.
      
      * Thanks to Nathan Howell for taking the iniative to get our own Haskell
        language ID for DWARF!
      
      (From Phabricator D396)
      cc481ec8
  28. 16 Dec, 2014 1 commit
    • Peter Wortmann's avatar
      Debug data extraction (NCG support) · f46aa733
      Peter Wortmann authored
      The purpose of the Debug module is to collect all required information
      to generate debug information (DWARF etc.) in the back-ends. Our main
      data structure is the "debug block", which carries all information we have
      about a block of code that is going to get produced.
      
      Notes:
      
      * Debug blocks are arranged into a tree according to tick scopes. This
        makes it easier to reason about inheritance rules. Note however that
        tick scopes are not guaranteed to form a tree, which requires us to
        "copy" ticks to not lose them.
      
      * This is also where we decide what source location we regard as
        representing a code block the "best". The heuristic is basically that
        we want the most specific source reference that comes from the same file
        we are currently compiling. This seems to be the most useful choice in
        my experience.
      
      * We are careful to not be too lazy so we don't end up breaking streaming.
        Debug data will be kept alive until the end of codegen, after all.
      
      * We change native assembler dumps to happen right away for every Cmm group.
        This simplifies the code somewhat and is consistent with how pretty much
        all of GHC handles dumps with respect to streamed code.
      
      (From Phabricator D169)
      f46aa733
  29. 10 Dec, 2014 1 commit
  30. 21 Nov, 2014 2 commits
    • Alan Zimmerman's avatar
      Add API Annotations · 803fc5db
      Alan Zimmerman authored
      Summary:
      The final design and discussion is captured at
      https://ghc.haskell.org/trac/ghc/wiki/GhcAstAnnotations
      
      This is a proof of concept implementation of a completely
      separate annotation structure, populated in the parser,and tied to the
      AST by means of a virtual "node-key" comprising the surrounding
      SrcSpan and a value derived from the specific constructor used for the
      node.
      
      The key parts of the design are the following.
      
      == The Annotations ==
      
      In `hsSyn/ApiAnnotation.hs`
      
      ```lang=haskell
      type ApiAnns = (Map.Map ApiAnnKey SrcSpan, Map.Map SrcSpan [Located Token])
      
      type ApiAnnKey = (SrcSpan,AnnKeywordId)
      
      -- ---------------------------------------------------------------------
      
      -- | Retrieve an annotation based on the @SrcSpan@ of the annotated AST
      -- element, and the known type of the annotation.
      getAnnotation :: ApiAnns -> SrcSpan -> AnnKeywordId -> Maybe SrcSpan
      getAnnotation (anns,_) span ann = Map.lookup (span,ann) anns
      
      -- |Retrieve the comments allocated to the current @SrcSpan@
      getAnnotationComments :: ApiAnns -> SrcSpan -> [Located Token]
      getAnnotationComments (_,anns) span =
        case Map.lookup span anns of
          Just cs -> cs
          Nothing -> []
      
      -- | Note: in general the names of these are taken from the
      -- corresponding token, unless otherwise noted
      data AnnKeywordId
               = AnnAs
               | AnnBang
               | AnnClass
               | AnnClose -- ^ } or ] or ) or #) etc
               | AnnComma
               | AnnDarrow
               | AnnData
               | AnnDcolon
               ....
      ```
      
      == Capturing in the lexer/parser ==
      
      The annotations are captured in the lexer / parser by extending PState to include a field
      
      In `parser/Lexer.x`
      
      ```lang=haskell
      data PState = PState {
              ....
              annotations :: [(ApiAnnKey,SrcSpan)]
              -- Annotations giving the locations of 'noise' tokens in the
              -- source, so that users of the GHC API can do source to
              -- source conversions.
           }
      ```
      
      The lexer exposes a helper function to add an annotation
      
      ```lang=haskell
      addAnnotation :: SrcSpan -> Ann -> SrcSpan -> P ()
      addAnnotation l a v = P $ \s -> POk s {
        annotations = ((AK l a), v) : annotations s
        } ()
      
      ```
      
      The parser also has some helper functions of the form
      
      ```lang=haskell
      type MaybeAnn = Maybe (SrcSpan -> P ())
      
      gl = getLoc
      gj x = Just (gl x)
      
      ams :: Located a -> [MaybeAnn] -> P (Located a)
      ams a@(L l _) bs = (mapM_ (\a -> a l) $ catMaybes bs) >> return a
      ```
      
      This allows annotations to be captured in the parser by means of
      
      ```
      ctypedoc :: { LHsType RdrName }
              : 'forall' tv_bndrs '.' ctypedoc {% hintExplicitForall (getLoc $1) >>
                                                  ams (LL $ mkExplicitHsForAllTy $2 (noLoc []) $4)
                                                      [mj AnnForall $1,mj AnnDot $3] }
              | context '=>' ctypedoc         {% ams (LL $ mkQualifiedHsForAllTy   $1 $3)
                                                     [mj AnnDarrow $2] }
              | ipvar '::' type               {% ams (LL (HsIParamTy (unLoc $1) $3))
                                                     [mj AnnDcolon $2] }
              | typedoc                       { $1 }
      ```
      
      == Parse result ==
      
      ```lang-haskell
      data HsParsedModule = HsParsedModule {
          hpm_module    :: Located (HsModule RdrName),
          hpm_src_files :: [FilePath],
             -- ^ extra source files (e.g. from #includes).  The lexer collects
             -- these from '# <file> <line>' pragmas, which the C preprocessor
             -- leaves behind.  These files and their timestamps are stored in
             -- the .hi file, so that we can force recompilation if any of
             -- them change (#3589)
          hpm_annotations :: ApiAnns
        }
      
      -- | The result of successful parsing.
      data ParsedModule =
        ParsedModule { pm_mod_summary   :: ModSummary
                     , pm_parsed_source :: ParsedSource
                     , pm_extra_src_files :: [FilePath]
                     , pm_annotations :: ApiAnns }
      ```
      
      This diff depends on D426
      
      Test Plan: sh ./validate
      
      Reviewers: austin, simonpj, Mikolaj
      
      Reviewed By: simonpj, Mikolaj
      
      Subscribers: Mikolaj, goldfire, thomie, carter
      
      Differential Revision: https://phabricator.haskell.org/D438
      
      GHC Trac Issues: #9628
      803fc5db
    • eir@cis.upenn.edu's avatar
      Fix #7484, checking for good binder names in Convert. · da2fca9e
      eir@cis.upenn.edu authored
      This commit also refactors a bunch of lexeme-oriented code into
      a new module Lexeme, and includes a submodule update for haddock.
      da2fca9e
  31. 20 Nov, 2014 1 commit
  32. 19 Nov, 2014 1 commit
  33. 04 Nov, 2014 1 commit
    • Simon Peyton Jones's avatar
      Simon's major commit to re-engineer the constraint solver · 5770029a
      Simon Peyton Jones authored
      The driving change is this:
      
      * The canonical CFunEqCan constraints now have the form
             [G] F xis ~ fsk
             [W] F xis ~ fmv
        where fsk is a flatten-skolem, and fmv is a flatten-meta-variable
        Think of them as the name of the type-function application
      
      See Note [The flattening story] in TcFlatten.  A flatten-meta-variable
      is distinguishable by its MetaInfo of FlatMetaTv
      
      This in turn led to an enormous cascade of other changes, which simplify
      and modularise the constraint solver.  In particular:
      
      * Basic data types
          * I got rid of inert_solved_funeqs altogether. It serves no useful
            role that inert_flat_cache does not solve.
      
          * I added wl_implics to the WorkList, as a convenient place to
            accumulate newly-emitted implications; see Note [Residual
            implications] in TcSMonad.
      
          * I eliminated tcs_ty_binds altogether. These were the bindings
            for unification variables that we have now solved by
            unification.  We kept them in a finite map and did the
            side-effecting unification later.  But in cannonicalisation we
            had to look up in the side-effected mutable tyvars anyway, so
            nothing was being gained.
      
            Our original idea was that the solver would be pure, and would
            be a no-op if you discarded its results, but this was already
            not-true for implications since we update their evidence
            bindings in an imperative way.  So rather than the uneasy
            compromise, it's now clearly imperative!
      
      * I split out the flatten/unflatten code into a new module, TcFlatten
      
      * I simplified and articulated explicitly the (rather hazy) invariants
        for the inert substitution inert_eqs.  See Note [eqCanRewrite] and
        See Note [Applying the inert substitution] in TcFlatten
      
      * Unflattening is now done (by TcFlatten.unflatten) after solveFlats,
        before solving nested implications.  This turned out to simplify a
        lot of code. Previously, unflattening was done as part of zonking, at
        the very very end.
      
          * Eager unflattening allowed me to remove the unpleasant ic_fsks
            field of an Implication (hurrah)
      
          * Eager unflattening made the TcSimplify.floatEqualities function
            much simpler (just float equalities looking like a ~ ty, where a
            is an untouchable meta-tyvar).
      
          * Likewise the idea of "pushing wanteds in as givens" could be
            completely eliminated.
      
      * I radically simplified the code that determines when there are
        'given' equalities, and hence whether we can float 'wanted' equalies
        out.  See TcSMonad.getNoGivenEqs, and Note [When does an implication
        have given equalities?].
      
        This allowed me to get rid of the unpleasant inert_no_eqs flag in InertCans.
      
      * As part of this given-equality stuff, I fixed Trac #9211. See Note
        [Let-bound skolems] in TcSMonad
      
      * Orientation of tyvar/tyvar equalities (a ~ b) was partly done during
        canonicalisation, but then repeated in the spontaneous-solve stage
        (trySpontaneousSolveTwoWay). Now it is done exclusively during
        canonicalisation, which keeps all the code in one place.  See
        Note [Canonical orientation for tyvar/tyvar equality constraints]
        in TcCanonical
      5770029a