GitLab

- put panic related functions into GHC.Utils.Panic
- put trace related functions using DynFlags in GHC.Driver.Ppr

One step closer making Outputable fully independent of DynFlags.

Bump haddock submodule

Update Haddock submodule

Metric Increase:
   haddock.compiler

Update Haddock submodule

Update Haddock submodule

Metric Increase:
   haddock.compiler

Metric Decrease:
    ManyConstructors
    T12707
    T13035
    T1969

submodule updates: nofib, haddock

Add StgToCmm module hierarchy. Platform modules that are used in several
other places (NCG, LLVM codegen, Cmm transformations) are put into
GHC.Platform.

Unfortunately this will require more work; register allocation is
quite broken.

This reverts commit acd79558.

This adds support for constructing vector types from Float#, Double# etc
and performing arithmetic operations on them
Cleaned-Up-By: Ben Gamari <ben@well-typed.com>

* simplifies registers to have GPR, Float and Double, by removing the SSE2 and X87 Constructors
* makes -msse2 assumed/default for x86 platforms, fixing a long standing nondeterminism in rounding
behavior in 32bit haskell code
* removes the 80bit floating point representation from the supported float sizes
* theres still 1 tiny bit of x87 support needed,
for handling float and double return values in FFI calls  wrt the C ABI on x86_32,
but this one piece does not leak into the rest of NCG.
* Lots of code thats not been touched in a long time got deleted as a
consequence of all of this

all in all, this change paves the way towards a lot of future further
improvements in how GHC handles floating point computations, along with
making the native code gen more accessible to a larger pool of contributors.

This is the first step of implementing:
https://github.com/ghc-proposals/ghc-proposals/pull/74

The main highlights/changes:

    primops.txt.pp gets two new sections for two new primitive types for
    signed and unsigned 8-bit integers (Int8# and Word8 respectively) along
    with basic arithmetic and comparison operations. PrimRep/RuntimeRep get
    two new constructors for them. All of the primops translate into the
    existing MachOPs.

    For CmmCalls the codegen will now zero-extend the values at call
    site (so that they can be moved to the right register) and then truncate
    them back their original width.

    x86 native codegen needed some updates, since it wasn't able to deal
    with the new widths, but all the changes are quite localized. LLVM
    backend seems to just work.

This is the second attempt at merging this, after the first attempt in
D4475 had to be backed out due to regressions on i386.

Bumps binary submodule.
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: ./validate (on both x86-{32,64})

Reviewers: bgamari, hvr, goldfire, simonmar

Subscribers: rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5258

This unfortunately broke i386 support since it introduced references to
byte-sized registers that don't exist on that architecture.

Reverts binary submodule

This reverts commit 5d5307f9.

This is the first step of implementing:
https://github.com/ghc-proposals/ghc-proposals/pull/74

The main highlights/changes:

- `primops.txt.pp` gets two new sections for two new primitive types
  for signed and unsigned 8-bit integers (`Int8#` and `Word8`
  respectively) along with basic arithmetic and comparison
  operations. `PrimRep`/`RuntimeRep` get two new constructors for
  them. All of the primops translate into the existing `MachOP`s.

- For `CmmCall`s the codegen will now zero-extend the values at call
  site (so that they can be moved to the right register) and then
  truncate them back their original width.

- x86 native codegen needed some updates, since it wasn't able to deal
  with the new widths, but all the changes are quite localized. LLVM
  backend seems to just work.

Bumps binary submodule.
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: ./validate with new tests

Reviewers: hvr, goldfire, bgamari, simonmar

Subscribers: Abhiroop, dfeuer, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4475

This patch adds foldl' to GhcPrelude and changes must occurences
of foldl to foldl'. This leads to better performance especially
for quick builds where GHC does not perform strictness analysis.

It does change strictness behaviour when we use foldl' to turn
a argument list into function applications. But this is only a
drawback if code looks ONLY at the last argument but not at the first.
And as the benchmarks show leads to fewer allocations in practice
at O2.

Compiler performance for Nofib:

O2 Allocations:
        -1 s.d.                -----            -0.0%
        +1 s.d.                -----            -0.0%
        Average                -----            -0.0%

O2 Compile Time:
        -1 s.d.                -----            -2.8%
        +1 s.d.                -----            +1.3%
        Average                -----            -0.8%

O0 Allocations:
        -1 s.d.                -----            -0.2%
        +1 s.d.                -----            -0.1%
        Average                -----            -0.2%

Test Plan: ci

Reviewers: goldfire, bgamari, simonmar, tdammers, monoidal

Reviewed By: bgamari, monoidal

Subscribers: tdammers, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4929

Summary:
An info table with an SRT normally looks like this:

    StgWord64 srt_offset
    StgClosureInfo layout
    StgWord32 layout
    StgWord32 has_srt

But we only need 32 bits for srt_offset on x86_64, because the small
memory model requires that code segments are at most 2GB. So we can
optimise this to

    StgClosureInfo layout
    StgWord32 layout
    StgWord32 srt_offset

saving a word.  We can tell whether the info table has an SRT or not,
because zero is not a valid srt_offset, so zero still indicates that
there's no SRT.

Test Plan:
* validate
* For results, see D4632.

Reviewers: bgamari, niteria, osa1, erikd

Subscribers: thomie, carter

Differential Revision: https://phabricator.haskell.org/D4634

Summary:
This change makes it possible to generate a static 32-bit relative label
offset on x86_64. Currently we can only generate word-sized label
offsets.

This will be used in D4634 to shrink info tables.  See D4632 for more
details.

Test Plan: See D4632

Reviewers: bgamari, niteria, michalt, erikd, jrtc27, osa1

Subscribers: thomie, carter

Differential Revision: https://phabricator.haskell.org/D4633

This removes a bunch of unnecessary includes of `HsVersions.h` along
with unnecessary CPP (e.g., due to checking for DEBUG which can be
achieved by looking at `debugIsOn`)
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: ./validate

Reviewers: bgamari, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4462

Test Plan: validate

Reviewers: bgamari, erikd

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4380

This switches the compiler/ component to get compiled with
-XNoImplicitPrelude and a `import GhcPrelude` is inserted in all
modules.

This is motivated by the upcoming "Prelude" re-export of
`Semigroup((<>))` which would cause lots of name clashes in every
modulewhich imports also `Outputable`

Reviewers: austin, goldfire, bgamari, alanz, simonmar

Reviewed By: bgamari

Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari

Differential Revision: https://phabricator.haskell.org/D3989

This makes the two functions strict in the accumulator - it seems that
there are only two users of those functions: `CmmLive` and `CmmSink`
and in both cases the strict fold fits better.

The commit also removes a few unused functions (`filterRegsUsed`),
instances (for `Maybe` and `RegSet`) and gets rid of unnecessary
inculde of `HsVersions.h`.

The performance effect of avoiding unnecessary thunks is mostly
negligible, although we do allocate a tiny bit less (nofib's section
on compile allocations):
```
-1 s.d.                -----            -0.2%
+1 s.d.                -----            -0.1%
Average                -----            -0.2%
```
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: validate

Reviewers: simonmar, austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2723

The idea behind adding special "rubbish" arguments was in unboxed sum types
depending on the tag some arguments are not used and we don't want to move some
special values (like 0 for literals and some special pointer for boxed slots)
for those arguments (to stack locations or registers). "StgRubbishArg" was an
indicator to the code generator that the value won't be used. During Stg-to-Cmm
we were then not generating any move or store instructions at all.

This caused problems in the register allocator because some variables were only
initialized in some code paths. As an example, suppose we have this STG: (after
unarise)

    Lib.$WT =
        \r [dt_sit]
            case
                case dt_sit of {
                  Lib.F dt_siv [Occ=Once] ->
                      (#,,#) [1# dt_siv StgRubbishArg::GHC.Prim.Int#];
                  Lib.I dt_siw [Occ=Once] ->
                      (#,,#) [2# StgRubbishArg::GHC.Types.Any dt_siw];
                }
            of
            dt_six
            { (#,,#) us_giC us_giD us_giE -> Lib.T [us_giC us_giD us_giE];
            };

This basically unpacks a sum type to an unboxed sum with 3 fields, and then
moves the unboxed sum to a constructor (`Lib.T`).

This is the Cmm for the inner case expression (case expression in the scrutinee
position of the outer case):

    ciN:
        ...
        -- look at dt_sit's tag
        if (_ciT::P64 != 1) goto ciS; else goto ciR;
    ciS: -- Tag is 2, i.e. Lib.F
        _siw::I64 = I64[_siu::P64 + 6];
        _giE::I64 = _siw::I64;
        _giD::P64 = stg_RUBBISH_ENTRY_info;
        _giC::I64 = 2;
        goto ciU;
    ciR: -- Tag is 1, i.e. Lib.I
        _siv::P64 = P64[_siu::P64 + 7];
        _giD::P64 = _siv::P64;
        _giC::I64 = 1;
        goto ciU;

Here one of the blocks `ciS` and `ciR` is executed and then the execution
continues to `ciR`, but only `ciS` initializes `_giE`, in the other branch
`_giE` is not initialized, because it's "rubbish" in the STG and so we don't
generate an assignment during code generator. The code generator then panics
during the register allocations:

    ghc-stage1: panic! (the 'impossible' happened)
      (GHC version 8.1.20160722 for x86_64-unknown-linux):
            LocalReg's live-in to graph ciY {_giE::I64}

(`_giD` is also "rubbish" in `ciS`, but it's still initialized because it's a
pointer slot, we have to initialize it otherwise garbage collector follows the
pointer to some random place. So we only remove assignment if the "rubbish" arg
has unboxed type.)

This patch removes `StgRubbishArg` and `CmmArg`. We now always initialize
rubbish slots. If the slot is for boxed types we use the existing `absentError`,
otherwise we initialize the slot with literal 0.

Reviewers: simonpj, erikd, austin, simonmar, bgamari

Reviewed By: erikd

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2446

Summary:
This patch implements primitive unboxed sum types, as described in
https://ghc.haskell.org/trac/ghc/wiki/UnpackedSumTypes.

Main changes are:

- Add new syntax for unboxed sums types, terms and patterns. Hidden
  behind `-XUnboxedSums`.

- Add unlifted unboxed sum type constructors and data constructors,
  extend type and pattern checkers and desugarer.

- Add new RuntimeRep for unboxed sums.

- Extend unarise pass to translate unboxed sums to unboxed tuples right
  before code generation.

- Add `StgRubbishArg` to `StgArg`, and a new type `CmmArg` for better
  code generation when sum values are involved.

- Add user manual section for unboxed sums.

Some other changes:

- Generalize `UbxTupleRep` to `MultiRep` and `UbxTupAlt` to
  `MultiValAlt` to be able to use those with both sums and tuples.

- Don't use `tyConPrimRep` in `isVoidTy`: `tyConPrimRep` is really
  wrong, given an `Any` `TyCon`, there's no way to tell what its kind
  is, but `kindPrimRep` and in turn `tyConPrimRep` returns `PtrRep`.

- Fix some bugs on the way: #12375.

Not included in this patch:

- Update Haddock for new the new unboxed sum syntax.

- `TemplateHaskell` support is left as future work.

For reviewers:

- Front-end code is mostly trivial and adapted from unboxed tuple code
  for type checking, pattern checking, renaming, desugaring etc.

- Main translation routines are in `RepType` and `UnariseStg`.
  Documentation in `UnariseStg` should be enough for understanding
  what's going on.

Credits:

- Johan Tibell wrote the initial front-end and interface file
  extensions.

- Simon Peyton Jones reviewed this patch many times, wrote some code,
  and helped with debugging.

Reviewers: bgamari, alanz, goldfire, RyanGlScott, simonpj, austin,
           simonmar, hvr, erikd

Reviewed By: simonpj

Subscribers: Iceland_jack, ggreif, ezyang, RyanGlScott, goldfire,
             thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D2259

Test Plan: validate

Reviewers: austin, bgamari, simonmar

Reviewed By: bgamari, simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2351

Ord Unique can be a source of invisible, accidental
nondeterminism as explained in Note [No Ord for Unique].
This removes it, leaving a note with rationale.

It's unfortunate that I had to write Ord instances for
codegen data structures by hand, but I believe that it's a
right trade-off here.

Test Plan: ./validate

Reviewers: simonmar, austin, bgamari

Reviewed By: simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2370

GHC Trac Issues: #4012

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.

We will need to use these to setup proper unwinding information for the
stg_stop_thread closure. This pokes a hole in the STG abstraction,
exposing the machine's stack pointer register so that we can accomplish
this. We also expose a dummy return address register, which corresponds
to the register used to hold the DWARF return address.

Differential Revision: https://phabricator.haskell.org/D1225

Summary:
On x86_64, commit e2f6bbd3 assigned
the STG registers F1 and D1 the same hardware register (xmm1), and
the same for the registers F2 and D2, etc. When mixing calls to
functions involving Float#s and Double#s, this can cause wrong Cmm
optimizations that assume the F1 and D1 registers are independent.

Reviewers: simonpj, austin

Reviewed By: austin

Subscribers: simonpj, thomie, bgamari

Differential Revision: https://phabricator.haskell.org/D993

GHC Trac Issues: #10521

The purpose of silent superclass parameters was to solve the
awkward problem of superclass dictinaries being bound to bottom.
See THE PROBLEM in Note [Recursive superclasses] in TcInstDcls

Although the silent-superclass idea worked,

  * It had non-local consequences, and had effects even in Haddock,
    where we had to discard silent parameters before displaying
    instance declarations

  * It had unexpected peformance costs, shown up by Trac #3064 and its
    test case.  In monad-transformer code, when constructing a Monad
    dictionary you had to pass an Applicative dictionary; and to
    construct that you neede a Functor dictionary. Yet these extra
    dictionaries were often never used.  (All this got much worse when
    we added Applicative as a superclass of Monad.) Test T3064
    compiled *far* faster after silent superclasses were eliminated.

  * It introduced new bugs.  For example SilentParametersOverlapping,
    T5051, and T7862, all failed to compile because of instance overlap
    directly because of the silent-superclass trick.

So this patch takes a new approach, which I worked out with Dimitrios
in the closing hours before Christmas.  It is described in detail
in THE PROBLEM in Note [Recursive superclasses] in TcInstDcls.

Seems to work great!

Quite a bit of knock-on effect

 * The main implementation work is in tcSuperClasses in TcInstDcls
   Everything else is fall-out

 * IdInfo.DFunId no longer needs its n-silent argument
   * Ditto IDFunId in IfaceSyn
   * Hence interface file format changes

 * Now that DFunIds do not have silent superclass parameters, printing
   out instance declarations is simpler. There is tiny knock-on effect
   in Haddock, so that submodule is updated

 * I realised that when computing the "size of a dictionary type"
   in TcValidity.sizePred, we should be rather conservative about
   type functions, which can arbitrarily increase the size of a type.
   Hence the new datatype TypeSize, which has a TSBig constructor for
   "arbitrarily big".

 * instDFunType moves from TcSMonad to Inst

 * Interestingly, CmmNode and CmmExpr both now need a non-silent
   (Ord r) in a couple of instance declarations. These were previously
   silent but must now be explicit.

 * Quite a bit of wibbling in error messages

In some cases, the layout of the LANGUAGE/OPTIONS_GHC lines has been
reorganized, while following the convention, to

- place `{-# LANGUAGE #-}` pragmas at the top of the source file, before
  any `{-# OPTIONS_GHC #-}`-lines.

- Moreover, if the list of language extensions fit into a single
  `{-# LANGUAGE ... -#}`-line (shorter than 80 characters), keep it on one
  line. Otherwise split into `{-# LANGUAGE ... -#}`-lines for each
  individual language extension. In both cases, try to keep the
  enumeration alphabetically ordered.
  (The latter layout is preferable as it's more diff-friendly)

While at it, this also replaces obsolete `{-# OPTIONS ... #-}` pragma
occurences by `{-# OPTIONS_GHC ... #-}` pragmas.

This patch adds support for 6 XMM registers on x86-64 which overlap with the F
and D registers and may hold 128-bit wide SIMD vectors. Because there is not a
good way to attach type information to STG registers, we aggressively bitcast in
the LLVM back-end.

We would like to calculate register liveness for global registers as well as
local registers, so this patch generalizes the existing infrastructure to set
the stage.