GitLab

Fix a long-standing lossage of rules attached to class operations
(A one-line fix to SimplCore.updateBinders.)

Rename 'doDiscard' to 'lexPragma', and make it EOF-resistant.
As was, it would run off the end of a StringBuffer (and SIGSEGV,
most likely) if a pragma wasn't properly closed.

Provide finer-grained control for turning off mk/target.mk's
'all', 'boot' and 'install' rules. i.e., instead of having
the variable NO_ALL_TARGETS control the defnition of rules
for all three, NO_ALL_TARGET, NO_BOOT_TARGET, and NO_INSTALL_TARGET
lets you individually control which ones you don't want.

Sub-projects (GC and HDirect, for example) have the need
to turn off the 'boot' rule, which is what motivated this
change.

Tweaks to the 5.02 InstallShield to improve presentation and the range of
help files available.

Inline BasicTypes.CompilerPhase tysyn to workaround
Outputable <--> BasicTypes module loop.

Add note that it's possible to move the Windows GHC tree around if you want
to (e.g. to get it on a path without spaces).

Wibble

Specialise reduce

------------------
		Simon's big commit
		------------------
	[ These files seem to have been left out for some reason ]


This commit, which I don't think I can sensibly do piecemeal, consists
of the things I've been doing recently, mainly directed at making
Manuel, George, and Marcin happier with RULES.


Reogranise the simplifier
~~~~~~~~~~~~~~~~~~~~~~~~~
1. The simplifier's environment is now an explicit parameter.  This
makes it a bit easier to figure out where it is going.

2. Constructor arguments can now be arbitrary expressions, except
when the application is the RHS of a let(rec).  This makes it much
easier to match rules like

	RULES
	    "foo"  f (h x, g y) = f' x y

In the simplifier, it's Simplify.mkAtomicArgs that ANF-ises a
constructor application where necessary.  In the occurrence analyser,
there's a new piece of context info (OccEncl) to say whether a
constructor app is in a place where it should be in ANF.  (Unless
it knows this it'll give occurrence info which will inline the
argument back into the constructor app.)

3. I'm experimenting with doing the "float-past big lambda" transformation
in the full laziness pass, rather than mixed in with the simplifier (was
tryRhsTyLam).

4.  Arrange that
	case (coerce (S,T) (x,y)) of ...
will simplify.  Previous it didn't.
A local change to CoreUtils.exprIsConApp_maybe.

5. Do a better job in CoreUtils.exprEtaExpandArity when there's an
error function in one branch.


Phase numbers, RULES, and INLINE pragmas
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1.  Phase numbers decrease from N towards zero (instead of increasing).
This makes it easier to add new earlier phases, which is what users want
to do.

2.  RULES get their own phase number, N, and are disabled in phases before N.

e.g. 	{-# RULES "foo" [2] forall x y.  f (x,y) = f' x y #-}

Note the [2], which says "only active in phase 2 and later".

3.  INLINE and NOINLINE pragmas have a phase number to.  This is now treated
in just the same way as the phase number on RULE; that is, the Id is not inlined
in phases earlier than N.  In phase N and later the Id *may* be inlined, and
here is where INLINE and NOINLINE differ: INLNE makes the RHS look small, so
as soon as it *may* be inlined it probably *will* be inlined.

The syntax of the phase number on an INLINE/NOINLINE pragma has changed to be
like the RULES case (i.e. in square brackets).  This should also make sure
you examine all such phase numbers; many will need to change now the numbering
is reversed.

Inlining Ids is no longer affected at all by whether the Id appears on the
LHS of a rule.  Now it's up to the programmer to put a suitable INLINE/NOINLINE
pragma to stop it being inlined too early.


Implementation notes:

*  A new data type, BasicTypes.Activation says when a rule or inline pragma
is active.   Functions isAlwaysActive, isNeverActive, isActive, do the
obvious thing (all in BasicTypes).

* Slight change in the SimplifierSwitch data type, which led to a lot of
simplifier-specific code moving from CmdLineOpts to SimplMonad; a Good Thing.

* The InlinePragma in the IdInfo of an Id is now simply an Activation saying
when the Id can be inlined.  (It used to be a rather bizarre pair of a
Bool and a (Maybe Phase), so this is much much easier to understand.)

* The simplifier has a "mode" environment switch, replacing the old
black list.  Unfortunately the data type decl has to be in
CmdLineOpts, because it's an argument to the CoreDoSimplify switch

    data SimplifierMode = SimplGently | SimplPhase Int

Here "gently" means "no rules, no inlining".   All the crucial
inlining decisions are now collected together in SimplMonad
(preInlineUnconditionally, postInlineUnconditionally, activeInline,
activeRule).


Specialisation
~~~~~~~~~~~~~~
1.  Only dictionary *functions* are made INLINE, not dictionaries that
have no parameters.  (This inline-dictionary-function thing is Marcin's
idea and I'm still not sure whether it's a good idea.  But it's definitely
a Bad Idea when there are no arguments.)

2.  Be prepared to specialise an INLINE function: an easy fix in
Specialise.lhs

But there is still a problem, which is that the INLINE wins
at the call site, so we don't use the specialised version anyway.
I'm still unsure whether it makes sense to SPECIALISE something
you want to INLINE.





Random smaller things
~~~~~~~~~~~~~~~~~~~~~~

* builtinRules (there was only one, but may be more) in PrelRules are now
  incorporated.   They were being ignored before...

* OrdList.foldOL -->  OrdList.foldrOL, OrdList.foldlOL

* Some tidying up of the tidyOpenTyVar, tidyTyVar functions.  I've
  forgotten exactly what!

------------------
		Simon's big commit
		------------------

This commit, which I don't think I can sensibly do piecemeal, consists
of the things I've been doing recently, mainly directed at making
Manuel, George, and Marcin happier with RULES.


Reogranise the simplifier
~~~~~~~~~~~~~~~~~~~~~~~~~
1. The simplifier's environment is now an explicit parameter.  This
makes it a bit easier to figure out where it is going.

2. Constructor arguments can now be arbitrary expressions, except
when the application is the RHS of a let(rec).  This makes it much
easier to match rules like

	RULES
	    "foo"  f (h x, g y) = f' x y

In the simplifier, it's Simplify.mkAtomicArgs that ANF-ises a
constructor application where necessary.  In the occurrence analyser,
there's a new piece of context info (OccEncl) to say whether a
constructor app is in a place where it should be in ANF.  (Unless
it knows this it'll give occurrence info which will inline the
argument back into the constructor app.)

3. I'm experimenting with doing the "float-past big lambda" transformation
in the full laziness pass, rather than mixed in with the simplifier (was
tryRhsTyLam).

4.  Arrange that
	case (coerce (S,T) (x,y)) of ...
will simplify.  Previous it didn't.
A local change to CoreUtils.exprIsConApp_maybe.

5. Do a better job in CoreUtils.exprEtaExpandArity when there's an
error function in one branch.


Phase numbers, RULES, and INLINE pragmas
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1.  Phase numbers decrease from N towards zero (instead of increasing).
This makes it easier to add new earlier phases, which is what users want
to do.

2.  RULES get their own phase number, N, and are disabled in phases before N.

e.g. 	{-# RULES "foo" [2] forall x y.  f (x,y) = f' x y #-}

Note the [2], which says "only active in phase 2 and later".

3.  INLINE and NOINLINE pragmas have a phase number to.  This is now treated
in just the same way as the phase number on RULE; that is, the Id is not inlined
in phases earlier than N.  In phase N and later the Id *may* be inlined, and
here is where INLINE and NOINLINE differ: INLNE makes the RHS look small, so
as soon as it *may* be inlined it probably *will* be inlined.

The syntax of the phase number on an INLINE/NOINLINE pragma has changed to be
like the RULES case (i.e. in square brackets).  This should also make sure
you examine all such phase numbers; many will need to change now the numbering
is reversed.

Inlining Ids is no longer affected at all by whether the Id appears on the
LHS of a rule.  Now it's up to the programmer to put a suitable INLINE/NOINLINE
pragma to stop it being inlined too early.


Implementation notes:

*  A new data type, BasicTypes.Activation says when a rule or inline pragma
is active.   Functions isAlwaysActive, isNeverActive, isActive, do the
obvious thing (all in BasicTypes).

* Slight change in the SimplifierSwitch data type, which led to a lot of
simplifier-specific code moving from CmdLineOpts to SimplMonad; a Good Thing.

* The InlinePragma in the IdInfo of an Id is now simply an Activation saying
when the Id can be inlined.  (It used to be a rather bizarre pair of a
Bool and a (Maybe Phase), so this is much much easier to understand.)

* The simplifier has a "mode" environment switch, replacing the old
black list.  Unfortunately the data type decl has to be in
CmdLineOpts, because it's an argument to the CoreDoSimplify switch

    data SimplifierMode = SimplGently | SimplPhase Int

Here "gently" means "no rules, no inlining".   All the crucial
inlining decisions are now collected together in SimplMonad
(preInlineUnconditionally, postInlineUnconditionally, activeInline,
activeRule).


Specialisation
~~~~~~~~~~~~~~
1.  Only dictionary *functions* are made INLINE, not dictionaries that
have no parameters.  (This inline-dictionary-function thing is Marcin's
idea and I'm still not sure whether it's a good idea.  But it's definitely
a Bad Idea when there are no arguments.)

2.  Be prepared to specialise an INLINE function: an easy fix in
Specialise.lhs

But there is still a problem, which is that the INLINE wins
at the call site, so we don't use the specialised version anyway.
I'm still unsure whether it makes sense to SPECIALISE something
you want to INLINE.





Random smaller things
~~~~~~~~~~~~~~~~~~~~~~

* builtinRules (there was only one, but may be more) in PrelRules are now
  incorporated.   They were being ignored before...

* OrdList.foldOL -->  OrdList.foldrOL, OrdList.foldlOL

* Some tidying up of the tidyOpenTyVar, tidyTyVar functions.  I've
  forgotten exactly what!

-------------------------------
	Code generation and SRT hygiene
	-------------------------------

This is a big tidy up commit.  I don't think it breaks anything,
but it certainly makes the code clearer (to me).

I'm not certain that you can use it without sucking in my other
big commit... they come from the same tree.


Core-to-STG, live variables and Static Reference Tables (SRTs)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I did a big tidy-up of the live-variable computation in CoreToStg.
The key idea is that the live variables consist of two parts:
	dynamic live vars
	static live vars (CAFs)

These two always travel round together, but they were always
treated separately by the code until now. Now it's a new data type:

type LiveInfo = (StgLiveVars, 	-- Dynamic live variables;
				-- i.e. ones with a nested (non-top-level) binding
		 CafSet)	-- Static live variables;
				-- i.e. top-level variables that are CAFs or refer to them

There's lots of documentation in CoreToStg.

Code generation
~~~~~~~~~~~~~~~
Arising from this, I found that SRT labels were stored in
a LambdaFormInfo during code generation, whereas they *ought*
to be in the ClosureInfo (which in turn contains a LambdaFormInfo).

This led to lots of changes in ClosureInfo, and I took the opportunity
to make it into a labelled record.

Similarly, I made the data type in AbstractC a bit more explicit:

  -- C_SRT is what StgSyn.SRT gets translated to...
  -- we add a label for the table, and expect only the 'offset/length' form

data C_SRT = NoC_SRT
	   | C_SRT CLabel !Int{-offset-} !Int{-length-}

(Previously there were bottoms lying around.)

- split documentation off into a separate package
- adapt to new docbook setup in RH7.1

Make the print stylesheet generate a TOC for sets (so the PDF manual
has a front TOC indicating that it contains both the user's guide and
libraries guide).

A simple question with a simple answer; how refreshing.

ENODEV should really be an UnsupportedOperation, not NoSuchThing.

A failure while trying to set O_NONBLOCK on a file descriptor should
be a non-fatal error.  It turns out that on FreeBSD it is an error
(ENODEV) to try to set O_NONBLOCK on /dev/null.

MERGE TO STABLE

Let's try that last commit again, and get it right this time...

When skipping a nested comment, keep track of the source location of
the comment opener, so that we can report it in an error message
rather than reporting the line at the end of the file.

Also noticed a couple of ineficiencies in the nested comment code, so
fixed those too.

Add the text about ForeignPtr vs. Ptr

Stick with trad. function syntax in prev commit; avoids unnecessary Perl versioning issues

Pass the "-mieee" flag to gcc, so that we get IEEE floating-point.
MERGE TO STABLE

Remove mention of building guide (no longer shipped with binary dist
on Windows), and add set.html target (need to make HTML docs).

Fix the mangle rule since the definition of GHC_MANGLER changed

MERGE TO STABLE

Mention the use of the -no-hs-main flag when talking about linking
programs where main() is not provided by GHC.

- don't omit "test" dirs from the source distribution
- remove some backslashes from the sed commands to make them work here

Added a diagram showing the biography of a closure.
Made minor changes to a few paragraphs and footnotes.

Updates and fixes for 5.02 release.

PLEASE MERGE.

Add extra notes.

Windows port can now handle spaces in filenames, so delete the bit saying it
can't. Also change URL of download page (it was pointing to the now defunct
download.html).

PLEASE MERGE PLEASE, GO ON, PRETTY PLEASE WITH SUGAR

(this also necessitates the site's copy of the docs being updated. Sorry)

use $(LD) instead of hard-wired ld.

Use $(LD) instead of hard-wired ld.

Add  LD = ld

Remove the GHC-specific instructions from this file, and bring it up
to date in various ways.

Fix a bug with arithmetic primops on platforms where StgInt is not int,
such as the 64-bit Alpha.  The bug is that, for example,

    1# `iShiftL#` 32#

returns zero rather than 2^32.  The reason is that we should cast the
macro arguments to I_ in the definition of iShiftL#, but did not.

MERGE TO STABLE

We need to pass the -w flag to gcc when compilng *_stub.c files
in addition to when compilng *.hc files.

MERGE TO STABLE

CLEAN_FILES += PrelPrimopWrappers.hs # MERGE TO STABLE

Disable debugging message.  (Only affects Alpha.)  MERGE TO STABLE

Fix the "find" commands we use to build a source distribution.
Previously, it said things like "-exec path/{}", which doesn't work
on many find's ({} really should only appear by itself in an argument).
Now we pipe the output of find -print to sed and then to sh.  I hope
the piping to sh doesn't break source distribution creation on Win32.

MERGE TO STABLE

Alphas: The heroic Simon Marlow found a bug in the Digital UNIX
assembler (!) wherein .quad constants inside .text sections are
first narrowed to 32 bits then sign-extended back to 64 bits.
This obviously screws up our 64-bit bitmaps, so we work around
the bug by replacing .quad with .align 3 + .long + .long
MERGE TO STABLE

Well, GHCi doesn't work on the Alpha now, so don't even bother building it. MERGE TO STABLE