module/language/tree-il/optimize.scm

   1 ;;; Tree-il optimizer
   2
   3 ;; Copyright (C) 2009 Free Software Foundation, Inc.
   4
   5 ;; This program is free software; you can redistribute it and/or modify
   6 ;; it under the terms of the GNU General Public License as published by
   7 ;; the Free Software Foundation; either version 2, or (at your option)
   8 ;; any later version.
   9 ;;
  10 ;; This program is distributed in the hope that it will be useful,
  11 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ;; GNU General Public License for more details.
  14 ;;
  15 ;; You should have received a copy of the GNU General Public License
  16 ;; along with this program; see the file COPYING.  If not, write to
  17 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 ;; Boston, MA 02111-1307, USA.
  19
  20 ;;; Code:
  21
  22 (define-module (language tree-il optimize)
  23   #:use-module (system base syntax)
  24   #:use-module (language tree-il)
  25   #:use-module (language tree-il inline)
  26   #:export (optimize!))
  27
  28 (define (env-module e)
  29   (if e (car e) (current-module)))
  30
  31 (define (optimize! x env opts)
  32   (expand-primitives! (resolve-primitives! x (env-module env))))
  33
  34 ;; Possible optimizations:
  35 ;; * constant folding, propagation
  36 ;; * procedure inlining
  37 ;;   * always when single call site
  38 ;;   * always for "trivial" procs
  39 ;;   * otherwise who knows
  40 ;; * dead code elimination
  41 ;; * degenerate case optimizations
  42 ;; * "fixing letrec"
  43
  44 (define *interesting-primitive-names*
  45   '(apply @apply
  46     call-with-values @call-with-values
  47     call-with-current-continuation @call-with-current-continuation
  48     values
  49     ;; compile-time-environment
  50     eq? eqv? equal?
  51     = < > <= >= zero?
  52     + * - / 1- 1+ quotient remainder modulo
  53     not
  54     pair? null? list? acons cons cons*
  55
  56     car cdr
  57     set-car! set-cdr!
  58
  59     caar cadr cdar cddr
  60
  61     caaar caadr cadar caddr cdaar cdadr cddar cdddr
  62
  63     caaaar caaadr caadar caaddr cadaar cadadr caddar cadddr
  64     cdaaar cdaadr cdadar cdaddr cddaar cddadr cdddar cddddr))
  65
  66 (define *interesting-primitive-vars*
  67   (let ((h (make-hash-table)))
  68     (for-each (lambda (x)
  69                 (hashq-set! h (module-variable the-root-module x) x))
  70               *interesting-primitive-names*)
  71     h))
  72
  73 (define (resolve-primitives! x mod)
  74   (post-order!
  75    (lambda (x)
  76      (record-case x
  77        ((<toplevel-ref> src name)
  78         (and (hashq-ref *interesting-primitive-vars*
  79                         (module-variable mod name))
  80              (make-primitive-ref src name)))
  81        ((<module-ref> src mod name public?)
  82         ;; for the moment, we're disabling primitive resolution for
  83         ;; public refs because resolve-interface can raise errors.
  84         (let ((m (and (not public?) (resolve-module mod))))
  85           (and m (hashq-ref *interesting-primitive-vars*
  86                             (module-variable m name))
  87                (make-primitive-ref src name))))
  88        (else #f)))
  89    x))