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This commits relaxes the invariants of the Core syntax so that a
top-level variable can be bound to a primitive string literal of type
Addr#.

This commit:

* Relaxes the invatiants of the Core, and allows top-level bindings whose
  type is Addr# as long as their RHS is either a primitive string literal or
  another variable.

* Allows the simplifier and the full-laziness transformer to float out
  primitive string literals to the top leve.

* Introduces the new StgGenTopBinding type to accomodate top-level Addr#
  bindings.

* Introduces a new type of labels in the object code, with the suffix "_bytes",
  for exported top-level Addr# bindings.

* Makes some built-in rules more robust. This was necessary to keep them
  functional after the above changes.

This is a continuation of D2554.

Rebasing notes:
This had two slightly suspicious performance regressions:

* T12425: bytes allocated regressed by roughly 5%
* T4029: bytes allocated regressed by a bit over 1%
* T13035: bytes allocated regressed by a bit over 5%

These deserve additional investigation.

Rebased by: bgamari.

Test Plan: ./validate --slow

Reviewers: goldfire, trofi, simonmar, simonpj, austin, hvr, bgamari

Reviewed By: trofi, simonpj, bgamari

Subscribers: trofi, simonpj, gridaphobe, thomie

Differential Revision: https://phabricator.haskell.org/D2605

GHC Trac Issues: #8472

Strangely my previous attempts at resolving this all seemed to end in
perplexing segmentation faults in the GHC testsuite (including some
rather recent attempts). Somehow this attempt miraculously works.

However, there was one wrinkle that I still need to work out fully: we
need to consider Lits as non-trivial in cpeArg. Failure to do this means
that we would transform something like,

    $trModule = TrModule "HelloWorld"#

into

    $trModule = case "HelloWorld"# of x { __DEFAULT -> TrModule x }

Which then fails the consistentStgInfo check in CoreToStg for reasons
that I am still trying to work out.

Mark T12757 as fixed

Reviewers: simonmar, simonpj, austin

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2666

GHC Trac Issues: #11158

In particular I renamed
  'triv' to 'arg'
  CpeTriv to CpeArg
in Note [CorePrep invariants], with knock on consequences.

This is groundwork for the fix to Trac #11158

In the previous patch, I handled lazy @(Int -> Int) f x
correctly, but failed to handle lazy @Int (f x) (we need
to collect arguments in f x).
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari, nomeata

Reviewed By: nomeata

Subscribers: simonmar, thomie

Differential Revision: https://phabricator.haskell.org/D2471

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2444

GHC Trac Issues: #12472

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2209

Summary:
This mostly follows the plan detailed by the discussion
Simon and I had, with one difference: instead of grabbing
the free variables of the trivial expressions to get the
embedded Ids, we just use getIdFromTrivialExpr_maybe to extract
out the Id.  If there is no Id, the expression cannot
refer to a function (as there are no literal functions)
and thus we do not need to saturate.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2309

GHC Trac Issues: #12076

There's no functional change here, just tidying up

The function tryEtaReducePrep was being over-ambitious.
When Breakpoint ticks were involved (i.e. in GHCi), eta
reduction left an out-of-scope variable in the Tick.

Easily fixed. Fixes the original report in Trac #111728.

This adds timings and allocation figures to the compiler's output when
run with `-v2` in an effort to ease performance analysis.

Todo:
  * Documentation
  * Where else should we add these?
  * Perhaps we should remove some of the now-arguably-redundant
    `showPass` occurrences where they are
  * Must we force more?
  * Perhaps we should place this behind a `-ftimings` instead of `-v2`

Test Plan: `ghc -v2 Test.hs`, look at the output

Reviewers: hvr, goldfire, simonmar, austin

Reviewed By: simonmar

Subscribers: angerman, michalt, niteria, ezyang, thomie

Differential Revision: https://phabricator.haskell.org/D1959

'lazy' was doing part of its job, but not all!  In particular,
an application
  f (lazy e)
where f is strict, was still being compiled using call-by-value in
CorePrep.  This defeated the purpose of defining catch as
   catch a b = catch# (lazy a) b
See Trac #11555, and Neil Mitchell's test case in comment:14

This patch makes 'lazy' behave properly. I updated Note [lazyId magic]
in MkId, but all the action is in CorePrep.

I can't say I really like this, but it does the job.

See Note [TYPE] in TysPrim. There are still some outstanding
pieces in #11471 though, so this doesn't actually nail the bug.

This commit also contains a few performance improvements:

* Short-cut equality checking of nullary type syns

* Compare types before kinds in eqType

* INLINE coreViewOneStarKind

* Store tycon binders separately from kinds.

This resulted in a ~10% performance improvement in compiling
the Cabal package. No change in functionality other than
performance. (This affects the interface file format, though.)

This commit updates the haddock submodule.

This was causing trouble as we had to remember when to use "unLifted"
and when to use "unlifted".

"unlifted" is used instead of "unLifted" as it's a single word.

Reviewers: austin, hvr, goldfire, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1852

Summary:
In the past the canonical way for constructing an SDoc string literal was the
composition `ptext . sLit`.  But for some time now we have function `text` that
does the same.  Plus it has some rules that optimize its runtime behaviour.
This patch takes all uses of `ptext . sLit` in the compiler and replaces them
with calls to `text`.  The main benefits of this patch are clener (shorter) code
and less dependencies between module, because many modules now do not need to
import `FastString`.  I don't expect any performance benefits - we mostly use
SDocs to report errors and it seems there is little to be gained here.

Test Plan: ./validate

Reviewers: bgamari, austin, goldfire, hvr, alanz

Subscribers: goldfire, thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D1784

runRW# isn't inlined until CorePrep, so it's good to expose its
strictness.  Moreover, if we don't we can get obscure failures
in coreToStg; see Note [runRW arg] in CorePrep.

This fixes Trac #11291, and makes DfltProb1 compile with -O
always in order to expose it more vigorously

Since GHC 8.1/8.2 only needs to be bootstrap-able by GHC 7.10 and
GHC 8.0 (and GHC 8.2), we can now finally drop all that pre-AMP
compatibility CPP-mess for good!

Reviewers: austin, goldfire, bgamari

Subscribers: goldfire, thomie, erikd

Differential Revision: https://phabricator.haskell.org/D1724

Instead of substituting, just augment the environment.
Less code, more efficient.

And the previous version had a bogus in-scope set which
triggered a WARNING

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.

As you'll see from Trac #11155, the code generator was confused
by a binding let x = y in ....   Why did that happen? Because of
a (case y of {}) expression on the RHS.

The right thing is just to expand what a "trivial" expression is.

See Note [Empty case is trivial] in CoreUtils.

We now only strip block information from DebugBlocks when compiling with
`-g1`, intended to be used when only minimal debug information is
desired. `-g2` is assumed when `-g` is passed without any integer
argument.

Differential Revision: https://phabricator.haskell.org/D1281

Test Plan: validate

Reviewers: goldfire, erikd, rwbarton, simonpj, austin, simonmar, hvr

Reviewed By: simonpj

Subscribers: simonmar, thomie

Differential Revision: https://phabricator.haskell.org/D1103

GHC Trac Issues: #10678

Comes with Haddock submodule update.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1319

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1190

This localises the (revolting) initTcForLookup function, exposing
instead the more civilised interface for lookupGlobal

This completes what c774b28f (#9281)
started.  `integer-gmp-1.0` was added as an additional
`libraries/integer-gmp2` folder while retaining the ability to configure
GHC w/ the old `integer-gmp-0.5` to have a way back, and or the ability
to easily switch between old/new `integer-gmp` for benchmark/debugging
purposes.

This commit removes the old `libraries/integer-gmp` folder and moves
`libraries/integer-gmp2` into its place, while removing any mentions of
"gmp2" as well as the to support two different `integer-gmp` packages in
GHC's source-tree.

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D769

Summary: It looks like during .lhs -> .hs switch the comments were not updated. So doing exactly that.

Reviewers: austin, jstolarek, hvr, goldfire

Reviewed By: austin, jstolarek

Subscribers: thomie, goldfire

Differential Revision: https://phabricator.haskell.org/D621

GHC Trac Issues: #9986

See Note [Disgusting computation of CafRefs] in TidyPgm.

Also affects CoreUtils.rhsIsStatic.

The real solution here is to compute CAF and arity information
from the STG-program, and feed it back to tidied program for
the interface file and later GHCi clients.  A battle for another
day.

But at least this commit reduces the number of gratuitous CAFs, and
hence SRT entries.  And kills off a batch of ASSERT failures.

This is basically just about continuing maintaining source notes after
the Core stage. Unfortunately, this is more involved as it might seem,
as there are more restrictions on where ticks are allowed to show up.

Notes:

* We replace the StgTick / StgSCC constructors with a unified StgTick
  that can carry any tickish.

* For handling constructor or lambda applications, we generally float
  ticks out.

* Note that thanks to the NonLam placement, we know that source notes
  can never appear on lambdas. This means that as long as we are
  careful to always use mkTick, we will never violate CorePrep
  invariants.

* This is however not automatically true for eta expansion, which
  needs to somewhat awkwardly strip, then re-tick the expression in
  question.

* Where CorePrep floats out lets, we make sure to wrap them in the
  same spirit as FloatOut.

* Detecting selector thunks becomes a bit more involved, as we can run
  into ticks at multiple points.

(From Phabricator D169)

This patch introduces "SourceNote" tickishs that link Core to the
source code that generated it. The idea is to retain these source code
links throughout code transformations so we can eventually relate
object code all the way back to the original source (which we can,
say, encode as DWARF information to allow debugging).  We generate
these SourceNotes like other tickshs in the desugaring phase. The
activating command line flag is "-g", consistent with the flag other
compilers use to decide DWARF generation.

Keeping ticks from getting into the way of Core transformations is
tricky, but doable. The changes in this patch produce identical Core
in all cases I tested -- which at this point is GHC, all libraries and
nofib. Also note that this pass creates *lots* of tick nodes, which we
reduce somewhat by removing duplicated and overlapping source
ticks. This will still cause significant Tick "clumps" - a possible
future optimization could be to make Tick carry a list of Tickishs
instead of one at a time.

(From Phabricator D169)

There should be no bindings in this module for a GlobalId;
except after CoreTidy, when top-level bindings are globalised.

To check for this, I had to make the CoreToDo pass part of the
environment that Core Lint caries.  But CoreToDo is defined in
CoreMonad, which (before this patch) called CoreLint.

So I had to do quite a bit of refactoring, moving some
lint-invoking code into CoreLint itself.  Crucially, I also
more tcLookupImported_maybe, importDecl, and checkwiredInTyCon
from TcIface (which use CoreLint) to LoadIface (which doesn't).
This is probably better structure anyway.

So most of this patch is refactoring. The actual check for
GlobalIds is in CoreLint.lintAndScopeId

Signed-off-by: Austin Seipp <austin@well-typed.com>

This is done as a separate `integer-gmp2` backend library because it
turned out to become a complete rewrite from scratch.

Due to the different (over)allocation scheme and potentially different
accounting (via the new `{shrink,resize}MutableByteArray#` primitives),
some of the nofib benchmarks actually results in increased allocation
numbers (but not necessarily an increase in runtime!).  I believe the
allocation numbers could improve if `{resize,shrink}MutableByteArray#`
could be optimised to reallocate in-place more efficiently.

Here are the more apparent changes in the latest nofib comparision
between `integer-gmp` and `integer-gmp2`:

  ------------------------------------------------------------------
          Program     Size    Allocs   Runtime   Elapsed  TotalMem
  ------------------------------------------------------------------
              ...
       bernouilli    +1.6%    +15.3%     0.132     0.132      0.0%
              ...
     cryptarithm1    -2.2%      0.0%     -9.7%     -9.7%      0.0%
              ...
            fasta    -0.7%     -0.0%    +10.9%    +10.9%      0.0%
              ...
            kahan    +0.6%    +38.9%     0.169     0.169      0.0%
              ...
             lcss    -0.7%     -0.0%     -6.4%     -6.4%      0.0%
              ...
           mandel    +1.6%    +33.6%     0.049     0.049      0.0%
              ...
         pidigits    +0.8%     +8.5%     +3.9%     +3.9%      0.0%
            power    +1.4%    -23.8%    -18.6%    -18.6%    -16.7%
              ...
        primetest    +1.3%    +50.1%     0.085     0.085      0.0%
              ...
              rsa    +1.6%    +53.4%     0.026     0.026      0.0%
              ...
              scs    +1.2%     +6.6%     +6.5%     +6.6%    +14.3%
              ...
           symalg    +1.0%     +9.5%     0.010     0.010      0.0%
              ...
        transform    -0.6%     -0.0%     -5.9%     -5.9%      0.0%
              ...
  ------------------------------------------------------------------
              Min    -2.3%    -23.8%    -18.6%    -18.6%    -16.7%
              Max    +1.6%    +53.4%    +10.9%    +10.9%    +14.3%
   Geometric Mean    -0.3%     +1.9%     -0.8%     -0.8%     +0.0%

(see P35 / https://phabricator.haskell.org/P35 for full report)

By default, `INTEGER_LIBRARY=integer-gmp2` is active now, which results
in the package `integer-gmp-1.0.0.0` being registered in the package db.
The previous `integer-gmp-0.5.1.0` can be restored by setting
`INTEGER_LIBRARY=integer-gmp` (but will probably be removed altogether
for GHC 7.12). In-tree GMP support has been stolen from the old
`integer-gmp` (while unpatching the custom memory-allocators, as well as
forcing `-fPIC`)

A minor hack to `ghc-cabal` was necessary in order to support two different
`integer-gmp` packages (in different folders) with the same package key.

There will be a couple of follow-up commits re-implementing some features
that were dropped to keep D82 minimal, as well as further
clean-ups/improvements.

More information can be found via #9281 and
https://ghc.haskell.org/trac/ghc/wiki/Design/IntegerGmp2

Reviewed By: austin, rwbarton, simonmar

Differential Revision: https://phabricator.haskell.org/D82

I forget all the details, but I spent some time trying to
understand the current setup, and tried to simplify it a bit

Integer is currently a wired-in type for integer-gmp. This requires
replicating its inner structure in `TysWiredIn`, which makes it much
harder to change Integer to a more complex representation (as
e.g. needed for implementing #9281)

This commit stops `Integer` being a wired-in type, and makes it
known-key type instead, thereby simplifying code notably.

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D351

Summary:
Previously, both Cabal and GHC defined the type PackageId, and we expected
them to be roughly equivalent (but represented differently).  This refactoring
separates these two notions.

A package ID is a user-visible identifier; it's the thing you write in a
Cabal file, e.g. containers-0.9.  The components of this ID are semantically
meaningful, and decompose into a package name and a package vrsion.

A package key is an opaque identifier used by GHC to generate linking symbols.
Presently, it just consists of a package name and a package version, but
pursuant to #9265 we are planning to extend it to record other information.
Within a single executable, it uniquely identifies a package.  It is *not* an
InstalledPackageId, as the choice of a package key affects the ABI of a package
(whereas an InstalledPackageId is computed after compilation.)  Cabal computes
a package key for the package and passes it to GHC using -package-name (now
*extremely* misnamed).

As an added bonus, we don't have to worry about shadowing anymore.

As a follow on, we should introduce -current-package-key having the same role as
-package-name, and deprecate the old flag.  This commit is just renaming.

The haddock submodule needed to be updated.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, simonmar, hvr, austin

Subscribers: simonmar, relrod, carter

Differential Revision: https://phabricator.haskell.org/D79

Conflicts:
	compiler/main/HscTypes.lhs
	compiler/main/Packages.lhs
	utils/haddock