GitLab

Change the way SRTs are represented:

Previously, the SRT associated with a function or thunk would be a
sub-list of the enclosing top-level function's SRT.  But this approach
can lead to lots of duplication: if a CAF is referenced in several
different thunks, then it may appear several times in the SRT.
Let-no-escapes compound the problem, because the occurrence of a
let-no-escape-bound variable would expand to all the CAFs referred to
by the let-no-escape.

The new way is to describe the SRT associated with a function or thunk
as a (pointer+offset,bitmap) pair, where the pointer+offset points
into some SRT table (the enclosing function's SRT), and the bitmap
indicates which entries in this table are "live" for this closure.
The bitmap is stored in the 16 bits previously used for the length
field, but this rarely overflows.  When it does overflow, we store the
bitmap externally in a new "SRT descriptor".

Now the enclosing SRT can be a set, hence eliminating the duplicates.

Also, we now have one SRT per top-level function in a recursive group,
where previously we used to have one SRT for the whole group.  This
helps keep the size of SRTs down.

Bottom line: very little difference most of the time.  GHC itself got
slightly smaller.  One bad case of a module in GHC which had a huge
SRT has gone away.

While I was in the area:

  - Several parts of the back-end require bitmaps.  Functions for
    creating bitmaps are now centralised in the Bitmap module.

  - We were trying to be independent of word-size in a couple of
    places in the back end, but we've now abandoned that strategy so I
    simplified things a bit.

Comments only

Calling mmap() with a size > 3Gig results in EINVAL on Linux.  Catch
this case and report it as an out of memory condition instead of a
panic.

Comment only

Add optimistic-eval page; not linked yet

Improve notes on Cygwin installation

Another bugfix to tryM, this time for GHC 5.00--5.04

Updates:

  - Loading module Main without a main binding is no longer an error.

  - Clarify the section on libraries to note that it means object-code
    libraries, not source code.

  - Update the section on packages now that most packages are
    auto-loaded.

Comment only

Allow deriving(Show) for data types with unboxed fields

Print type of data constructors correctly in GHCi

Comments and formatting

Note about context in data type decls

Update: we now follow Haskell 98 w.r.t. exports from module Main.

-------------------------------------
  	     Implement deriving( Data )
	-------------------------------------

Implements deriving( Data ), where the Data class is defined
in Data.Generics; its the "scrap your boilerplate" Term class.

Ralf is still converging on the exact definition of the Data class,
so the details may change.

Import wibbles

-------------------------------------
		Main module exports
	-------------------------------------

Make it so that

   	    module Main where ....

exports everything defined in Main, as the report says it should.

Formatting only

Comments about eta expansion

Add support for unboxed Ints, Floats and Doubles to Template Haskell.

Make -t option to the script override the template file, just as -c
overrides the compiler, as the the documentation implies.  (Formerly -t
added an extra template file, which is not so useful.)

Use the DocBook 4.1 DTD instead of 3.1.  Seems to work fine...

Remove special cases for the setting of $(libdir) and $(datadir) on
mingw32, after discussion with Sigbjorn.

Unbreak Mac OS X build (#ifdef mixup)

update aLL_NON_PTRS for the new RET_DYN stack frame layout.

Add a compile-time sanity check that RESERVED_STACK_WORDS is right.

Comments to note the relationship between the RET_DYN stack frame size
and RESERVED_STACK_WORDS.

Following the recent change to the layout of the StgRetDyn frame, we
now need to bump RESERVED_STACK_WORDS because this governs the amount
of room which is guaranteed to be available on the stack in the event
of a stack check failure.

This accounts for at least one cause of recent crashes in the HEAD.

Strings in perl are compared by eq, not ==.
Fixes creating "nul" files on Unix.

s/symbol link/symbolic link/

Unbreak 2nd stage

- Add a note about the incorrect handling of the 'module Main where'
  header.

- While I'm here: fix out of date stuff, reformat and generally tidy up.

Make a leading '~' expand to $HOME in commands that load source files
(:load, :add) in addition to :cd which already had this behaviour.

Oops, forgot to update this file after the RET_DYN changes.

Order declarations in reifications in order of source line number.
The bugs still there but it bites less often now...

Also remove the type parameterisation and do some type renaming as
discussed on the template-haskell list.

Fix an obscure bug: the most general kind of heap check,
HEAP_CHECK_GEN(), is supposed to save the contents of *every* register
known to the STG machine (used in cases where we either can't figure
out which ones are live, or doing so would be too much hassle).  The
problem is that it wasn't saving the L1 register.

A slight complication arose in that saving the L1 register pushed the
size of the frame over the 16 words allowed for the size of the bitmap
stored in the frame, so I changed the layout of the frame a bit.
Describing all the registers using a single bitmap is overkill when
only 8 of them can actually be pointers, so now the bitmap is only 8
bits long and we always skip over a fixed number of non-ptr words to
account for all the non-ptr regs.  This is all described in StgMacros.h.

Fix the context for derived Typeable instances

Stage-2 wibbles to the Expected type changes

drop curious *_debug_opts_prefix tables; no longer used

Add a comment about the entry convention to stg_ap_* and why it's done
this way (thanks to Andy Moran for the prodding).