S  M  L   /   N  J

                  1  1  0  .  3  5      N  E  W  S
			
  		           August 24, 2001

			      WARNING

  	This version is intended for compiler hackers. The 
	version ought to be stable, however we have not run
	our full regression testing.

        http://cm.bell-labs.com/cm/cs/what/smlnj/index.html


Summary:

  Compiler sources have been reorganized into serveral CM libraries.
  There have been various changes to the exported interfaces themselves
  as well.

  Reorganization (and simplification) of the "Cells" interface in MLRISC.

  "Cluster" data structure removed from MLRISC, now using "graph"s
  throughout.

  Bug fixes to MLRISC.

  Updates to closure phase in compiler.  

--------------------------------------------------------------------------

Details:

Compiler library reorganization:

  We are currently making an effort of modularizing the compiler's sources
  so that well-defined parts can be easily reused by other projects.  For
  example, we now provide an ML parser library that is independent of
  the rest of the compiler.  An ML parser might be of interest to program
  analysis folks.  Similarly, there is an ML elaborator library, although
  its interface is not yet as clean as we would like it to make.
  Another important library that can be used independently by other
  projects (and has been for some time already, e.g., C-- and Moby), is
  MLRISC.  In the future we expect the FLINT optimizer to become its
  own library as well.  With this design, SML/NJ will consist of several
  large but generic and independently useful libraries together with SML/NJ-
  specific "glue" code.

  Here is the new library organization as implemented in 110.35:

  "Visible compiler"...

      $smlnj/viscomp/basics.cm
          - common definitions used by many or all of the libraries below
      $smlnj/viscomp/parser.cm
          - a Standard ML parser and data structures (ast)
      $smlnj/viscomp/elabdata.cm
          - data structures and utility functions for elaboration
            (absyn, types, static environments, ...)
      $smlnj/viscomp/elaborate.cm
          - a Standard ML type checker and elaborator
      $smlnj/viscomp/core.cm
          - FLINT optimizer and SML/NJ-specific glue code
      $smlnj/viscomp/execute.cm
          - SML/NJ object file ("binfile") handling, linking, execution
      $smlnj/viscomp/debugprof.cm
          - instrumentation phases (operating on data structures exported
            by elabdata.cm) for debugging (e.g., backtracing) and profiling
      $smlnj/compiler.cm
          - collection of structures (no longer nested within a single
            structure Compiler) that make up the "visible compiler"

      $smlnj/compiler/compiler.cm
          - legacy "structure Compiler"

  Architecture specific backends, part of the "visible compiler"...
      $smlnj/viscomp/alpha32.cm
      $smlnj/viscomp/hppa.cm
      $smlnj/viscomp/ppc.cm
      $smlnj/viscomp/sparc.cm
      $smlnj/viscomp/x86.cm

  Visible cross-compilers (collection of structures analogous to
  $smlnj/compiler.cm)...
      $smlnj/compiler/current.cm
      $smlnj/compiler/alpha32.cm
      $smlnj/compiler/hppa.cm
      $smlnj/compiler/ppc.cm
      $smlnj/compiler/sparc.cm
      $smlnj/compiler/x86.cm

  MLRISC:
      $smlnj/MLRISC/Control.cm
      $smlnj/MLRISC/Lib.cm
      $smlnj/MLRISC/Graphs.cm
      $smlnj/MLRISC/MLTREE.cm
      $smlnj/MLRISC/MLRISC.cm
      $smlnj/MLRISC/ALPHA.cm
      $smlnj/MLRISC/HPPA.cm
      $smlnj/MLRISC/PPC.cm
      $smlnj/MLRISC/SPARC.cm
      $smlnj/MLRISC/IA32.cm

  Compilation manager:

      $smlnj/cm.cm
      $smlnj/cm/cm.cm
      $smlnj/cm/tools.cm

  Bootstrap compiler(s), including cross-compilers:
      $smlnj/cmb.cm
      $smlnj/cmb/current.cm
      $smlnj/cmb/alpha32-unix.cm
      $smlnj/cmb/hppa-unix.cm
      $smlnj/cmb/ppc-unix.cm
      $smlnj/cmb/sparc-unix.cm
      $smlnj/cmb/x86-unix.cm
      $smlnj/cmb/x86-win32.cm

MLRISC changes:

* Lal has dramatically simplified the interface for CELLS in MLRISC.

  In summary, the cells interface is broken up into three parts:

  1. CellsBasis : CELLS_BASIS

	CellsBasis is a top level structure and common for all
        architectures.  it contains the definitions of basic datatypes
        and utility  functions over these types.

  2. functor Cells() : CELLS

	Cells generates an interface for CELLS that incorporates the
	specific resources on the target architecture, such as the 
	presence of special register classes, their number and size, 
	and various useful substructures.

  3. <ARCH>CELLS 
	
	e.g. SparcCells: SPARCCELLS

        <ARCH>CELLS usually contains additional bindings for special
	registers  on the architecture, such as:
	
		val r0 : cell		(* register zero *)
		val y : cell		(* Y register *)
		val psr : cell		(* processor status register *) 
		...
	
        The structure returned by applying the Cells functor is opened
        in this interface. 

  The main implication of all this is that the datatypes for cells is 
  split between CellsBasis and CELLS -- a fairly simple change for user
  code. 

* Removed "clusters" from MLRISC completely and replaced with "graphs".
  This will make it possible to integrate into SML/NJ various optimizations
  that had already been implemented for "graphs" (but for the benefit of
  other projects).

Bug fixes:

* Improved "closure" phase in FLINT.
* Bug fixes in MLRISC.