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My re-org of the case-merging transformation introduced a bug, which led
to incorrect code.   This only showed up occasionally, but it generated
incorrect code for PprC.pprCastReg in the stage-2 compiler. As a result
the stage-2 compiler ran without crashing, but itself generated bogus C.

For a change, this is one that Core Lint couldn't find, so the trail was
a bit longer.  The fix is easy (and commented).

Fixes Trac #1128
Please merge to STABLE

A rather obscure bug related to -fno-implicit-prelude.  
See Note [Used names with interface not loaded] in RnNames.

Easily fixed, however.  Test is rn051

See conc059.

This is the Windows counterpart to "Make the non-threaded-RTS
threadDelay wait at least as long as asked"

An egregious bug in the type checker meant that it was possible for a 
"signature type variable" (a MetaTv of SigTv form) to be instantatiated 
with a type-constructor application.  This destroys the invariant for
SigTv.

The fix is easy; adding the predicate TcType.isTyConableTyVar

Fixes Trac #1153

Test ghci.debugger/scripts/print018 covers this

Print 

"Breakpoint set at Main:26:13"

instead of

"Breakpoint set at (26,13)"

Now the user can say 

> :break add 13

at the ghci prompt and the debugger will use the first top level module as the target for the breakpoint

My code was doing unnecessary work when trying to get hold of all the BCOs in order to sniff the datacon names.
This involved calculating the transitive closure of a relation and was causing a huge performance slowdown in GHCi, as benchmarks uncovered. It turns out that this calculation was unnecessary.

Benchmarks have shown that making the formation of the list of locals more lazy can improve performance of -fdebugging up to 50% in some cases

For example, "ghc -E Foo.hs -o Foo.bar" just copies Foo.hs to
Foo.bar.  This patch adds a LINE pragma to the beginning of Foo.bar so
that further processing can track the location of the original file.

The motiviation for this is bug #1044.  When generating Haddock docs,
we preprocess the .hs to a .raw-hs, sometimes this doesn't involve any
actual preprocessing and in those cases we lose track of the original
filename.

Since thunks grew an extra padding word in GHC 6.6, closure_sizeW()
has been wrong for AP closures because it assumed compatible layout
between PAPs and APs.  One symptom is that the compacting GC would
crash if it encountered an AP.  APs conly crop up in GHCi or
when using asynchronous exceptions.

Fixes #1010

This patch improves the SpecConstr pass, by 
  a) making it work with join points
  b) making it generate specialisations transitively

As part of it, SpecConstr now carries a substitution with it, which
runs over the whole program as it goes.  This turned out to be 
a big win; simplified the implementation quite a bit.

I have *disabled* the specialisation on lambdas; it's pretty fragile,
and sometimes generates more and more specialisations. Something to
come back to, perhaps.

I rejigged the flag-handling a bit.  Now the specification of passes
in DynFlags is a bit nicer; see
	- optLevelFlags top-level data structure
	- runWhen function
	- CoreDoPasses constructor

There are now command-line flags
	-fspec-constr
	-fliberate-case
	-fspec-threshold=N
which do the obvious thing.  -O2 switches on both spec-constr and liberate-case.
You can use -fno-liberate-case, -fno-spec-constr after -O2 to switch them off again.

The spec-threshold applies to both these transformations; default value 200 for now.

(NB: this patch could conceivably require some bits of the 
following SpecConstr patch to compile cleanly.  It's conceptually
independent, but I'm not 100% certain that I've included all
the necessary bits here.)

This patch cleans up the simplifier's handling of various
otimisations for case expressions, notably
  - case elimination (discarding the case altogether)
  - merging identical alternatives
  - discarding impossible alternative
  - merging nested cases

Previously this was partly handled before, and partly after,
simplifying the case alternatives. The trouble with that is
that the dead-ness information on the case binders gets munged
during simplification, and that turned out to mean that 
case elmination essentially never happened -- stupid.

Now I've moved it all to before simplifying the alterntives.
In fact this reduces the amount of code, I think, and it's
certainly tidier.  I don't think there is any loss.

The ticky static flag was being poked too early, which lead to
breakage in the -prof way amongst other things.  I've installed some
sanity checking to make sure we catch this earlier if it happens again.

This happens when the build tree is a link-tree to the source tree,
because lndir will normally omit the _darcs directory.

Under GhcStage2HcOpts, "O" should be "-O"; fixed.

  Newtypes have always been a problem because they are not there at runtime, but we need to take them into account.
  
  Tests ghci.debugger/print011 and ghci.debugger/print012 cover this

Made a bit faster the test which gets done every time a running program hits a dynamic breakpoint. I moved the bounds checking inside a DEBUG pragma and replaced (IArray.!) for unsafeAt

Instead of asking for the last 100 patches, we just get the first 500
lines of output from darcs changes (ugh, better ideas welcome).

The code for -ddump-minimal-imports was erroneously using loadSrcInterface,
which looks only for *exposed* modules.  It should instead use loadSysInterface
which looks for all interfaces.

The fix is straightforward.  MERGE to 6.6 branch.

I added a slightly more helpful remark in the profiling
section of the manual about how to use ticky-ticky.

The following changes restore ticky-ticky profiling to functionality
from its formerly bit-rotted state. Sort of. (It got bit-rotted as part
of the switch to the C-- back-end.)

The way that ticky-ticky is supposed to work is documented in Section 5.7
of the GHC manual (though the manual doesn't mention that it hasn't worked
since sometime around 6.0, alas). Changes from this are as follows (which
I'll document on the wiki):

* In the past, you had to build all of the libraries with way=t in order to
use ticky-ticky, because it entailed a different closure layout. No longer.
You still need to do make way=t in rts/ in order to build the ticky RTS,
but you should now be able to mix ticky and non-ticky modules.

* Some of the counters that worked in the past aren't implemented yet.
I was originally just trying to get entry counts to work, so those should
be correct. The list of counters was never documented in the first place,
so I hope it's not too much of a disaster that some don't appear anymore.
Someday, someone (perhaps me) should document all the counters and what 
they do. For now, all of the counters are either accurate (or at least as
accurate as they always were), zero, or missing from the ticky profiling
report altogether.

This hasn't been particularly well-tested, but these changes shouldn't
affect anything except when compiling with -fticky-ticky (famous last
words...)

Implementation details:

I got rid of StgTicky.h, which in the past had the macros and declarations 
for all of the ticky counters. Now, those macros are defined in Cmm.h.
StgTicky.h was still there for inclusion in C code. Now, any remaining C
code simply cannot call the ticky macros -- or rather, they do call those
macros, but from the perspective of C code, they're defined as no-ops. 
(This shouldn't be too big a problem.)

I added a new file TickyCounter.h that has all the declarations for ticky
counters, as well as dummy macros for use in C code. Someday, these 
declarations should really be automatically generated, since they need
to be kept consistent with the macros defined in Cmm.h.

Other changes include getting rid of the header that was getting added to
closures before, and getting rid of various code having to do with eager
blackholing and permanent indirections (the changes under compiler/ 
and rts/Updates.*).

For non-release builds, we want to append a date to the version number
(e.g. 6.7.20070206).  Previously this was done by the nightly build
script, this new method figures out the snapshot version by querying
the darcs repository and finding the date of the most recent patch
(actually it finds the most recent of the last 100 patches, but that
should be good enough).  This is done by the configure script.

To handle source distributions, we create a file VERSION in the
top-level directory that contains the version number, and ship this in
the source distribution.  The configure script picks up the version
from this file if it doesn't see a _darcs directory.

This egregious omission led to Trac #1128.