GitLab

Here's the Note about the (simple) fix.  Apparently #8329 prevented all
23 packages of the Snap framework from compiling.

Note [Demand transformer for a ditionary selector]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If we evaluate (op dict-expr) under demand 'd', then we can push the demand 'd'
into the appropriate field of the dictionary. What *is* the appropriate field?
We just look at the strictness signature of the class op, which will be
something like: U(AAASAAAAA).  Then replace the 'S' by the demand 'd'.

For single-method classes, which are represented by newtypes the signature
of 'op' won't look like U(...), so the splitProdDmd_maybe will fail.
That's fine: if we are doing strictness analysis we are also doing inling,
so we'll have inlined 'op' into a cast.  So we can bale out in a conservative
way, returning topDmdType.

It is (just.. Trac #8329) possible to be running strictness analysis *without*
having inlined class ops from single-method classes.  Suppose you are using
ghc --make; and the first module has a local -O0 flag.  So you may load a class
without interface pragmas, ie (currently) without an unfolding for the class
ops.   Now if a subsequent module in the --make sweep has a local -O flag
you might do strictness analysis, but there is no inlining for the class op.
This is wierd so I'm not worried about whether this optimises brilliantly; but
it should not fall over.

This makes it possible to write

x = if | False -> if | False -> 1
                     | False -> 2
       | True -> 3

Layout normally inserts semicolons between declarations at the same
indentation level, so I added optional semicolons to the syntax for
guards in MultiWayIf syntax.  This is a bit of a hack, but the
alternative (a special kind of layout that doesn't insert semicolons)
seemed worse, or at least equally bad.

People often jump to the conclusion that functions aren't inlined
unless you say INLINE, so clarify the documentation to emphasize the
fact that you shouldn't normally need to use INLINE unless you need to
override the defaults.

volatile StgWord8 is not guaranteed to be atomic.

We were passing the function address to stg_gc_prim_p in R9, which was
wrong because the call was a high-level call and didn't declare R9 as
a parameter.  Passing R9 as an argument is the right way, but
unfortunately that exposed another bug: we were using the same macro
in some low-level Cmm, where it is illegal to call functions with
arguments (see Note [syntax of cmm files]).  So we now have low-level
variants of STK_CHK() and STK_CHK_P() for use in low-level Cmm code.

No AMP warnings will be issued anymore when the name is not imported
from Prelude anymore. For example, a local definition of 'join' is now
legal in modules containing 'import Prelude (map)' for example. This
allows better future-proofing of libraries.

See also http://ghc.haskell.org/trac/ghc/ticket/8004#comment:16

Authored-by: David Luposchainsky <dluposchainsky@gmail.com>
Signed-off-by: Austin Seipp <austin@well-typed.com>

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

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

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

On 32-bit platforms, the bitmap should be an array of
32-bit words, not Word64s.
Signed-off-by: Austin Seipp <austin@well-typed.com>

This was supposed to happen a long time ago, but later is better than
never. This makes `-fwarn-lazy-unlifted-bindings` into a no-op (with its
own warning) to be removed in GHC 7.10.

This fixes #8022.
Signed-off-by: Austin Seipp <austin@well-typed.com>

This applies attachment:sync-all-submodules-locally.diff from #8369

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

See also #4426

Authored-by: Edward Kmett <ekmett@gmail.com>
Authored-by: Austin Seipp <austin@well-typed.com>
Signed-off-by: Austin Seipp <austin@well-typed.com>

A value of type 'Proxy# a' can only be created through the new,
primitive witness 'proxy# :: Proxy# a' - a Proxy# has no runtime
representation and is thus free.

This lets us clean up the internals of TypeRep, as well as Adam's future
work concerning records (by using a zero-width primitive type.)
Authored-by: Edward Kmett <ekmett@gmail.com>
Authored-by: Austin Seipp <austin@well-typed.com>
Signed-off-by: Austin Seipp <austin@well-typed.com>

 - `primitive` is updated to upstream's HEAD which is essentially
   `primitive-0.5.1.0`, plus a core-lint-error workaround for #8355 and
   some minor cleanups.

 - `vector` is updated to upstreams `vector-0.10.9.1` release

Note: The upstream repo location has changed to GitHub,
      hence the update in the `packages` file
Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

Arash Rouhani authored Sep 24, 2013 and Gabor Greif committed Sep 24, 2013

Signed-off-by: Arash Rouhani <rarash@student.chalmers.se>

This is used in the definition of `ToNat1` in the `base` library
(module GHC.TypeLits).

whitehole_spin is only defined when PROF_SPIN is set.

*p is both read and written to by the cmpxchg instruction, and therefore
should be given the '+' constraint modifier.

(In GCC's extended ASM language, '+' means that the operand is both read
and written to whereas '=' means that it is only written to.)

Otherwise, the compiler is allowed to rewrite something like

SpinLock lock;
initSpinLock(&lock);       /* sets lock = 1 */
ACQUIRE_SPIN_LOCK(&lock);

into

SpinLock lock;
ACQUIRE_SPIN_LOCK(&lock);

because according to the asm statement, the previous value of 'lock' is
not important.

It has been deprecated for long and already removed from ghc --help

See also #5435.

Now we have to remember the the StablePtrs that get created by the
module initializer so that we can free them again in unloadObj().

The problem with unreachable code is that it might refer to undefined
registers.  This happens accidentally: a block can be orphaned by an
optimisation, for example when the result of a comparsion becomes
known.

The register allocator panics when it finds an undefined register,
because they shouldn't occur in generated code.  So we need to also
discard unreachable code to prevent this panic being triggered by
optimisations.

The register alloator already does a strongly-connected component
analysis, so it ought to be easy to make it discard unreachable code
as part of that traversal.  It turns out that we need a different
variant of the scc algorithm to do that (see Digraph), however the new
variant also generates slightly better code by putting the blocks
within a loop in a better order for register allocation.