-;;; Continuation-passing style (CPS) intermediate language (IL)
-
-;; Copyright (C) 2013 Free Software Foundation, Inc.
-
-;;;; This library is free software; you can redistribute it and/or
-;;;; modify it under the terms of the GNU Lesser General Public
-;;;; License as published by the Free Software Foundation; either
-;;;; version 3 of the License, or (at your option) any later version.
-;;;;
-;;;; This library is distributed in the hope that it will be useful,
-;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-;;;; Lesser General Public License for more details.
-;;;;
-;;;; You should have received a copy of the GNU Lesser General Public
-;;;; License along with this library; if not, write to the Free Software
-;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-
-;;; Commentary:
-;;;
-;;; Primcalls that don't correspond to VM instructions are treated as if
-;;; they are calls, and indeed the later reify-primitives pass turns
-;;; them into calls. Because no return arity checking is done for these
-;;; primitives, if a later optimization pass simplifies the primcall to
-;;; a VM operation, the tail of the simplification has to be a
-;;; primcall to 'values. Most of these primcalls can be elided, and
-;;; that is the job of this pass.
-;;;
-;;; Code:
-
-(define-module (language cps elide-values)
- #:use-module (ice-9 match)
- #:use-module (srfi srfi-26)
- #:use-module (language cps)
- #:use-module (language cps dfg)
- #:export (elide-values))
-
-(define (elide-values fun)
- (let ((conts (build-local-cont-table
- (match fun (($ $fun src meta free body) body)))))
- (define (visit-cont cont)
- (rewrite-cps-cont cont
- (($ $cont sym ($ $kargs names syms body))
- (sym ($kargs names syms ,(visit-term body))))
- (($ $cont sym ($ $kentry self tail clauses))
- (sym ($kentry self ,tail ,(map visit-cont clauses))))
- (($ $cont sym ($ $kclause arity body))
- (sym ($kclause ,arity ,(visit-cont body))))
- (($ $cont)
- ,cont)))
- (define (visit-term term)
- (rewrite-cps-term term
- (($ $letk conts body)
- ($letk ,(map visit-cont conts)
- ,(visit-term body)))
- (($ $letrec names syms funs body)
- ($letrec names syms (map elide-values funs)
- ,(visit-term body)))
- (($ $continue k src ($ $primcall 'values vals))
- ,(rewrite-cps-term (lookup-cont k conts)
- (($ $ktail)
- ($continue k src ($values vals)))
- (($ $ktrunc ($ $arity req () rest () #f) kargs)
- ,(cond
- ((and (not rest) (= (length vals) (length req)))
- (build-cps-term
- ($continue kargs src ($values vals))))
- ((and rest (>= (length vals) (length req)))
- (let-gensyms (krest rest)
- (let ((vals* (append (list-head vals (length req))
- (list rest))))
- (build-cps-term
- ($letk ((krest ($kargs ('rest) (rest)
- ($continue kargs src
- ($values vals*)))))
- ,(let lp ((tail (list-tail vals (length req)))
- (k krest))
- (match tail
- (()
- (build-cps-term ($continue k src
- ($const '()))))
- ((v . tail)
- (let-gensyms (krest rest)
- (build-cps-term
- ($letk ((krest ($kargs ('rest) (rest)
- ($continue k src
- ($primcall 'cons
- (v rest))))))
- ,(lp tail krest))))))))))))
- (else term)))
- (($ $kargs args)
- ,(if (< (length vals) (length args))
- term
- (let ((vals (list-head vals (length args))))
- (build-cps-term
- ($continue k src ($values vals))))))))
- (($ $continue k src (and fun ($ $fun)))
- ($continue k src ,(elide-values fun)))
- (($ $continue)
- ,term)))
-
- (rewrite-cps-exp fun
- (($ $fun src meta free body)
- ($fun src meta free ,(visit-cont body))))))
+;;; Continuation-passing style (CPS) intermediate language (IL)
+
+;; Copyright (C) 2013, 2014 Free Software Foundation, Inc.
+
+;;;; This library is free software; you can redistribute it and/or
+;;;; modify it under the terms of the GNU Lesser General Public
+;;;; License as published by the Free Software Foundation; either
+;;;; version 3 of the License, or (at your option) any later version.
+;;;;
+;;;; This library is distributed in the hope that it will be useful,
+;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;;;; Lesser General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU Lesser General Public
+;;;; License along with this library; if not, write to the Free Software
+;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Commentary:
+;;;
+;;; Primcalls that don't correspond to VM instructions are treated as if
+;;; they are calls, and indeed the later reify-primitives pass turns
+;;; them into calls. Because no return arity checking is done for these
+;;; primitives, if a later optimization pass simplifies the primcall to
+;;; a VM operation, the tail of the simplification has to be a
+;;; primcall to 'values. Most of these primcalls can be elided, and
+;;; that is the job of this pass.
+;;;
+;;; Code:
+
+(define-module (language cps elide-values)
+ #:use-module (ice-9 match)
+ #:use-module (srfi srfi-26)
+ #:use-module (language cps)
+ #:use-module (language cps dfg)
+ #:export (elide-values))
+
+(define (elide-values* fun conts)
+ (define (visit-cont cont)
+ (rewrite-cps-cont cont
+ (($ $cont sym ($ $kargs names syms body))
+ (sym ($kargs names syms ,(visit-term body))))
+ (($ $cont sym ($ $kfun src meta self tail clause))
+ (sym ($kfun src meta self ,tail ,(and clause (visit-cont clause)))))
+ (($ $cont sym ($ $kclause arity body alternate))
+ (sym ($kclause ,arity ,(visit-cont body)
+ ,(and alternate (visit-cont alternate)))))
+ (($ $cont)
+ ,cont)))
+ (define (visit-term term)
+ (rewrite-cps-term term
+ (($ $letk conts body)
+ ($letk ,(map visit-cont conts)
+ ,(visit-term body)))
+ (($ $letrec names syms funs body)
+ ($letrec names syms (map visit-fun funs)
+ ,(visit-term body)))
+ (($ $continue k src ($ $primcall 'values vals))
+ ,(rewrite-cps-term (vector-ref conts k)
+ (($ $ktail)
+ ($continue k src ($values vals)))
+ (($ $kreceive ($ $arity req () rest () #f) kargs)
+ ,(cond
+ ((and (not rest) (= (length vals) (length req)))
+ (build-cps-term
+ ($continue kargs src ($values vals))))
+ ((and rest (>= (length vals) (length req)))
+ (let-fresh (krest) (rest)
+ (let ((vals* (append (list-head vals (length req))
+ (list rest))))
+ (build-cps-term
+ ($letk ((krest ($kargs ('rest) (rest)
+ ($continue kargs src
+ ($values vals*)))))
+ ,(let lp ((tail (list-tail vals (length req)))
+ (k krest))
+ (match tail
+ (()
+ (build-cps-term ($continue k src
+ ($const '()))))
+ ((v . tail)
+ (let-fresh (krest) (rest)
+ (build-cps-term
+ ($letk ((krest ($kargs ('rest) (rest)
+ ($continue k src
+ ($primcall 'cons
+ (v rest))))))
+ ,(lp tail krest))))))))))))
+ (else term)))
+ (($ $kargs args)
+ ,(if (< (length vals) (length args))
+ term
+ (let ((vals (list-head vals (length args))))
+ (build-cps-term
+ ($continue k src ($values vals))))))))
+ (($ $continue k src (and fun ($ $fun)))
+ ($continue k src ,(visit-fun fun)))
+ (($ $continue)
+ ,term)))
+ (define (visit-fun fun)
+ (rewrite-cps-exp fun
+ (($ $fun free cont)
+ ($fun free ,(visit-cont cont)))))
+
+ (visit-cont fun))
+
+(define (elide-values fun)
+ (with-fresh-name-state fun
+ (let ((conts (build-cont-table fun)))
+ (elide-values* fun conts))))
HCoop / bpt / guile.git / blobdiff