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The strictness signature for a data con wrapper wasn't including any
dictionary arguments, which meant that bangs on the fields of a
constructor with an existential context would be moved to the wrong
fields.  See T14290 for an example.

Test Plan:
* New test T14290
* validate

Reviewers: simonpj, niteria, austin, bgamari, erikd

Reviewed By: simonpj, bgamari

Subscribers: rwbarton, thomie

GHC Trac Issues: #14290

Differential Revision: https://phabricator.haskell.org/D4040

This reverts commit da4687f6.

It's not entirely trivial to clean up the dead code this patch
introduced. In particular, when we see

```
case raiseIO# m s of
  s' -> e
```

we want to know that `e` is dead. For scrutinees that are properly
bottom (which we don't want to consider `raiseIO# m s` to be, this
is handled by rewriting `bot` to `case bot of {}`. But if we do
that for `raiseIO#`, we end up with

```
case raiseIO# m s of {}
```

which looks a lot like bottom and could confuse demand analysis.
I think we need to wait with this change until we have a more
complete story.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3413

They were `expect_broken` without any output. Add the actual
output and remove the `expect_broken`.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3306

The script I used is included as testsuite/driver/kill_extra_files.py,
though at this point it is for mostly historical interest.

Some of the tests in libraries/hpc relied on extra_files.py, so this
commit includes an update to that submodule.

One test in libraries/process also relies on extra_files.py, but we
cannot update that submodule so easily, so for now we special-case it
in the test driver.

Any variable with useful information (strict or used-once) will not be
included in lazy_fv (according to splitFVs). If we now also remove them
from the strictness signatures, their uses are not recorded anywhere –
and then probably considered absent.

this fixes #12368.

It also refactors dmdFix a bit, removes some redundancies (such as
passing around an strictness signature right next to an id, when that id
is guaranteed to have been annotated with that strictness signature).

Note that when fixed-point iteration does not terminate, we
conservatively delete their strictness signatures (set them to nopSig).
But this loses the information on how its strict free variables are
used!

Lazily used variables already escape via lazy_fvs. We ensure that in the
case of an aborted fixed-point iteration, also the strict variables are
put there (with a conservative demand of topDmd).

Differential Revision: https://phabricator.haskell.org/D2392

By making it believe that some deeply nested value is absent when it
really isn't. See #12368.

Summary:
The idea here is that this gives a more detailed stack trace in two
cases:

1. With `-prof` and `-fprof-auto`
2. In GHCi (see #11047)

Example, with an error inserted in nofib/shootout/binary-trees:

```
$ ./Main 3
Main: z
CallStack (from ImplicitParams):
  error, called at Main.hs:67:29 in main:Main
CallStack (from -prof):
  Main.check' (Main.hs:(67,1)-(68,82))
  Main.check (Main.hs:63:1-21)
  Main.stretch (Main.hs:32:35-57)
  Main.main.c (Main.hs:32:9-57)
  Main.main (Main.hs:(27,1)-(43,42))
  Main.CAF (<entire-module>)
```

This doesn't quite obsolete +RTS -xc, which also attempts to display
more information in the case when the error is in a CAF, but I'm
exploring other solutions to that.

Includes submodule updates.

Test Plan: validate

Reviewers: simonpj, ezyang, gridaphobe, bgamari, hvr, austin

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1426

Foreign calls may not be strict for lifted arguments. Fixes Trac #11076.

Test Plan: ./validate

Reviewers: simonpj, bgamari, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1464

GHC Trac Issues: #11076

The default top-level exception handler now uses the `Show` instance for
`ErrorCall` when printing exceptions, so it will actually print the out-of-band
data (e.g. `CallStack`s) in compiled binaries, instead of just printing the
error message.

This also updates the hpc submodule to fix the test output.

Reviewed By: austin, thomie

Differential Revision: https://phabricator.haskell.org/D1217

Trac #10218 reports a subtle bug that turned out to be:

- CSE invalidated the usage information computed
  by earlier demand analysis, by increasing sharing

- that made a single-entry thunk into a multi-entry thunk

- and with -feager-blackholing, that led to <<loop>>

The patch fixes it by making the CSE pass zap usage information for
let-bound identifiers.   It can be restored by -flate-dmd-anal.

(But making -flate-dmd-anal the default needs some careful work;
see Trac #7782.)

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

This is a tricky case exposed by Trac #9254.  I'm surprised it hasn't
shown up before, because it's happens when you use unsafePerformIO in
the right way.

Anyway, fixed now.  See Note [Analysing with absent demand]
in Demand.lhs

It's a bit confusing to have .gitignore files spread all over the
filesystem. This commit tries to consolidate those into one .gitignore
file per component. Moreover, we try to describe files to be ignored which
happen to have a common identifying pattern by glob patterns.
Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

I used this shell command to automatically generate the lists:

for i in `git ls-files -o --exclude-standard --directory`; do echo "`basename $i`" >> "`dirname "$i"`/.gitignore"; done
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>