interface contents

This is so that generated names like e.g. workers don't show up as
infix operators when using something like -ddump-simpl.

 * AnId
 * ACoAxiom
 * AConLike

Also make sure allocHeapClosure updates profiling counters with the
memory allocated.

Simon Marlow authored 11 years ago and tibbe committed 11 years ago

- Move array representation knowledge into SMRep

- Separate out low-level heap-object allocation so that we can reuse
  it from doNewArrayOp

- remove card-table initialisation, we can safely ignore the card
  table for newly allocated arrays.

Simon Marlow authored 11 years ago and tibbe committed 11 years ago

I'd like to be able to pack together non-pointer fields that are less
than a word in size, and this is a necessary prerequisite.

This results in a 46% runtime decrease when allocating an array of 16
unit elements on a 64-bit machine.

In order to allow newArray# to have both an inline and an out-of-line
implementation, cgOpApp is refactored slightly. The new implementation
of cgOpApp should make it easier to add other primops with both inline
and out-of-line implementations in the future.

Sorry about that...

Nowadays SetLevels floats case expressions as well as let-bindings,
and case expressions bind type variables.  We need to clone all such
floated binders, to avoid accidental name capture.  But I'd forgotten
to substitute for the cloned type variables, causing #8714.  (In the
olden days only Ids were cloned, from let-bindings.)

This patch fixes the bug and does quite a bit of clean-up refactoring
as well, by putting the context level in the LvlEnv.

There is no effect on performance, except that nofib 'rewrite' improves
allocations by 3%.  On investigation I think it was a fluke to do with
loop-cutting in big letrec nests.  But at least it's a fluke in the
right direction.

        Program           Size    Allocs   Runtime   Elapsed  TotalMem
--------------------------------------------------------------------------------
            Min          -0.4%     -3.0%    -19.4%    -19.4%    -26.7%
            Max          -0.0%     +0.0%    +17.9%    +17.9%      0.0%
 Geometric Mean          -0.1%     -0.0%     -0.7%     -0.7%     -0.4%

This build generates the same code as the "perf" build and is thus
good for compiling benchmarks and inspecting the generated
code. However, it compiles the stage2 compiler faster at the expense
of compiler user programs more slowly.

Yet another small way in which polymorphic kinds needs a bit of care
See Note [Unify kinds in deriving] in TcDeriv

The issue here is described in Note [Binding scoped type variables] in
TcPat.  When implementing this fix I was able to make things quite a
bit simpler:
 * The type variables in a type signature now never unify
   with each other, and so can be straightfoward skolems.
 * We only need the SigTv stuff for signatures in patterns,
   and for kind variables.

When deriving Functor, Foldable, Traversable, we need only look at the
way that the last type argument is treated.  It's fine for there to
be existentials etc, provided they don't affect the last type argument.

See Note [Check that the type variable is truly universal] in TcDeriv.

This fixes #8824.

Because of GADTs and casts we were getting binders whose
demand annotation was more deeply nested than made sense
for its type.

See Note [Trimming a demand to a type], in Demand.lhs,
which I reproduce here:

   Note [Trimming a demand to a type]
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   Consider this:

     f :: a -> Bool
     f x = case ... of
             A g1 -> case (x |> g1) of (p,q) -> ...
             B    -> error "urk"

   where A,B are the constructors of a GADT.  We'll get a U(U,U) demand
   on x from the A branch, but that's a stupid demand for x itself, which
   has type 'a'. Indeed we get ASSERTs going off (notably in
   splitUseProdDmd, Trac #8569).

   Bottom line: we really don't want to have a binder whose demand is more
   deeply-nested than its type.  There are various ways to tackle this.
   When processing (x |> g1), we could "trim" the incoming demand U(U,U)
   to match x's type.  But I'm currently doing so just at the moment when
   we pin a demand on a binder, in DmdAnal.findBndrDmd.

This patch improves the call arity analysis in various ways.

Most importantly, it enriches the analysis result information so that
when looking at a call, we do not have to make a random choice about
what side we want to take the information from. Instead we can combine
the results in a way that does not lose valuable information.

To do so, besides the incoming arities, we store remember "what can be
called with what", i.e. an undirected graph between the (interesting)
free variables of an expression. Of course it makes combining the
results a bit more tricky (especially mutual recursion), but still
doable.

The actually implemation of the graph structure is abstractly put away
in a module of its own (UnVarGraph.hs)

The implementation is geared towards efficiently representing the graphs
that we need (which can contain large complete and large complete
bipartite graphs, which would be huge in other representations). If
someone feels like designing data structures: There is surely some
speed-up to be obtained by improving that data structure.

Additionally, the analysis now takes into account that if a RHS stays a
thunk, then its calls happen only once, even if the variables the RHS is
bound to is evaluated multiple times, or is part of a recursive group.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

Note: The only visible change in `time-1.4.2` is at the SafeHaskell level

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>