;;;; Copyright (C) 2009-2014, 2017 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
;;;;
(define-module (language tree-il)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:use-module (ice-9 match)
#:use-module (system base syntax)
#:export (tree-il-src
<void> void? make-void void-src
<const> const? make-const const-src const-exp
<primitive-ref> primitive-ref? make-primitive-ref primitive-ref-src primitive-ref-name
<lexical-ref> lexical-ref? make-lexical-ref lexical-ref-src lexical-ref-name lexical-ref-gensym
<lexical-set> lexical-set? make-lexical-set lexical-set-src lexical-set-name lexical-set-gensym lexical-set-exp
<module-ref> module-ref? make-module-ref module-ref-src module-ref-mod module-ref-name module-ref-public?
<module-set> module-set? make-module-set module-set-src module-set-mod module-set-name module-set-public? module-set-exp
<toplevel-ref> toplevel-ref? make-toplevel-ref toplevel-ref-src toplevel-ref-name
<toplevel-set> toplevel-set? make-toplevel-set toplevel-set-src toplevel-set-name toplevel-set-exp
<toplevel-define> toplevel-define? make-toplevel-define toplevel-define-src toplevel-define-name toplevel-define-exp
<conditional> conditional? make-conditional conditional-src conditional-test conditional-consequent conditional-alternate
<call> call? make-call call-src call-proc call-args
<primcall> primcall? make-primcall primcall-src primcall-name primcall-args
<seq> seq? make-seq seq-src seq-head seq-tail
<lambda> lambda? make-lambda lambda-src lambda-meta lambda-body
<lambda-case> lambda-case? make-lambda-case lambda-case-src
;; idea: arity
lambda-case-req lambda-case-opt lambda-case-rest lambda-case-kw
lambda-case-inits lambda-case-gensyms
lambda-case-body lambda-case-alternate
<let> let? make-let let-src let-names let-gensyms let-vals let-body
<letrec> letrec? make-letrec letrec-src letrec-in-order? letrec-names letrec-gensyms letrec-vals letrec-body
<fix> fix? make-fix fix-src fix-names fix-gensyms fix-vals fix-body
<let-values> let-values? make-let-values let-values-src let-values-exp let-values-body
<prompt> prompt? make-prompt prompt-src prompt-escape-only? prompt-tag prompt-body prompt-handler
<abort> abort? make-abort abort-src abort-tag abort-args abort-tail
list->seq
parse-tree-il
unparse-tree-il
tree-il->scheme
tree-il-fold
make-tree-il-folder
post-order
pre-order
tree-il=?
tree-il-hash))
(define (print-tree-il exp port)
(format port "#<tree-il ~S>" (unparse-tree-il exp)))
(define-syntax borrow-core-vtables
(lambda (x)
(syntax-case x ()
((_)
(let lp ((n 0) (out '()))
(if (< n (vector-length %expanded-vtables))
(lp (1+ n)
(let* ((vtable (vector-ref %expanded-vtables n))
(stem (struct-ref vtable (+ vtable-offset-user 0)))
(fields (struct-ref vtable (+ vtable-offset-user 2)))
(sfields (map
(lambda (f) (datum->syntax x f))
fields))
(type (datum->syntax x (symbol-append '< stem '>)))
(ctor (datum->syntax x (symbol-append 'make- stem)))
(pred (datum->syntax x (symbol-append stem '?))))
(let lp ((n 0) (fields fields)
(out (cons*
#`(define (#,ctor #,@sfields)
(make-struct/no-tail #,type #,@sfields))
#`(define (#,pred x)
(and (struct? x)
(eq? (struct-vtable x) #,type)))
#`(struct-set! #,type vtable-index-printer
print-tree-il)
#`(define #,type
(vector-ref %expanded-vtables #,n))
out)))
(if (null? fields)
out
(lp (1+ n)
(cdr fields)
(let ((acc (datum->syntax
x (symbol-append stem '- (car fields)))))
(cons #`(define #,acc
(make-procedure-with-setter
(lambda (x) (struct-ref x #,n))
(lambda (x v) (struct-set! x #,n v))))
out)))))))
#`(begin #,@(reverse out))))))))
(borrow-core-vtables)
;; (<void>)
;; (<const> exp)
;; (<primitive-ref> name)
;; (<lexical-ref> name gensym)
;; (<lexical-set> name gensym exp)
;; (<module-ref> mod name public?)
;; (<module-set> mod name public? exp)
;; (<toplevel-ref> name)
;; (<toplevel-set> name exp)
;; (<toplevel-define> name exp)
;; (<conditional> test consequent alternate)
;; (<call> proc args)
;; (<primcall> name args)
;; (<seq> head tail)
;; (<lambda> meta body)
;; (<lambda-case> req opt rest kw inits gensyms body alternate)
;; (<let> names gensyms vals body)
;; (<letrec> in-order? names gensyms vals body)
(define-type (<tree-il> #:common-slots (src) #:printer print-tree-il)
(<fix> names gensyms vals body)
(<let-values> exp body)
(<prompt> escape-only? tag body handler)
(<abort> tag args tail))
;; A helper.
(define (list->seq loc exps)
(if (null? (cdr exps))
(car exps)
(make-seq loc (car exps) (list->seq #f (cdr exps)))))
(define (location x)
(and (pair? x)
(let ((props (source-properties x)))
(and (pair? props) props))))
(define (parse-tree-il exp)
(let ((loc (location exp))
(retrans (lambda (x) (parse-tree-il x))))
(match exp
(('void)
(make-void loc))
(('call proc . args)
(make-call loc (retrans proc) (map retrans args)))
(('primcall name . args)
(make-primcall loc name (map retrans args)))
(('if test consequent alternate)
(make-conditional loc (retrans test) (retrans consequent) (retrans alternate)))
(('primitive (and name (? symbol?)))
(make-primitive-ref loc name))
(('lexical (and name (? symbol?)))
(make-lexical-ref loc name name))
(('lexical (and name (? symbol?)) (and sym (? symbol?)))
(make-lexical-ref loc name sym))
(('set! ('lexical (and name (? symbol?))) exp)
(make-lexical-set loc name name (retrans exp)))
(('set! ('lexical (and name (? symbol?)) (and sym (? symbol?))) exp)
(make-lexical-set loc name sym (retrans exp)))
(('@ ((and mod (? symbol?)) ...) (and name (? symbol?)))
(make-module-ref loc mod name #t))
(('set! ('@ ((and mod (? symbol?)) ...) (and name (? symbol?))) exp)
(make-module-set loc mod name #t (retrans exp)))
(('@@ ((and mod (? symbol?)) ...) (and name (? symbol?)))
(make-module-ref loc mod name #f))
(('set! ('@@ ((and mod (? symbol?)) ...) (and name (? symbol?))) exp)
(make-module-set loc mod name #f (retrans exp)))
(('toplevel (and name (? symbol?)))
(make-toplevel-ref loc name))
(('set! ('toplevel (and name (? symbol?))) exp)
(make-toplevel-set loc name (retrans exp)))
(('define (and name (? symbol?)) exp)
(make-toplevel-define loc name (retrans exp)))
(('lambda meta body)
(make-lambda loc meta (retrans body)))
(('lambda-case ((req opt rest kw inits gensyms) body) alternate)
(make-lambda-case loc req opt rest kw
(map retrans inits) gensyms
(retrans body)
(and=> alternate retrans)))
(('lambda-case ((req opt rest kw inits gensyms) body))
(make-lambda-case loc req opt rest kw
(map retrans inits) gensyms
(retrans body)
#f))
(('const exp)
(make-const loc exp))
(('seq head tail)
(make-seq loc (retrans head) (retrans tail)))
;; Convenience.
(('begin . exps)
(list->seq loc (map retrans exps)))
(('let names gensyms vals body)
(make-let loc names gensyms (map retrans vals) (retrans body)))
(('letrec names gensyms vals body)
(make-letrec loc #f names gensyms (map retrans vals) (retrans body)))
(('letrec* names gensyms vals body)
(make-letrec loc #t names gensyms (map retrans vals) (retrans body)))
(('fix names gensyms vals body)
(make-fix loc names gensyms (map retrans vals) (retrans body)))
(('let-values exp body)
(make-let-values loc (retrans exp) (retrans body)))
(('prompt escape-only? tag body handler)
(make-prompt loc escape-only?
(retrans tag) (retrans body) (retrans handler)))
(('abort tag args tail)
(make-abort loc (retrans tag) (map retrans args) (retrans tail)))
(else
(error "unrecognized tree-il" exp)))))
(define (unparse-tree-il tree-il)
(match tree-il
(($ <void> src)
'(void))
(($ <call> src proc args)
`(call ,(unparse-tree-il proc) ,@(map unparse-tree-il args)))
(($ <primcall> src name args)
`(primcall ,name ,@(map unparse-tree-il args)))
(($ <conditional> src test consequent alternate)
`(if ,(unparse-tree-il test)
,(unparse-tree-il consequent)
,(unparse-tree-il alternate)))
(($ <primitive-ref> src name)
`(primitive ,name))
(($ <lexical-ref> src name gensym)
`(lexical ,name ,gensym))
(($ <lexical-set> src name gensym exp)
`(set! (lexical ,name ,gensym) ,(unparse-tree-il exp)))
(($ <module-ref> src mod name public?)
`(,(if public? '@ '@@) ,mod ,name))
(($ <module-set> src mod name public? exp)
`(set! (,(if public? '@ '@@) ,mod ,name) ,(unparse-tree-il exp)))
(($ <toplevel-ref> src name)
`(toplevel ,name))
(($ <toplevel-set> src name exp)
`(set! (toplevel ,name) ,(unparse-tree-il exp)))
(($ <toplevel-define> src name exp)
`(define ,name ,(unparse-tree-il exp)))
(($ <lambda> src meta body)
(if body
`(lambda ,meta ,(unparse-tree-il body))
`(lambda ,meta (lambda-case))))
(($ <lambda-case> src req opt rest kw inits gensyms body alternate)
`(lambda-case ((,req ,opt ,rest ,kw ,(map unparse-tree-il inits) ,gensyms)
,(unparse-tree-il body))
. ,(if alternate (list (unparse-tree-il alternate)) '())))
(($ <const> src exp)
`(const ,exp))
(($ <seq> src head tail)
`(seq ,(unparse-tree-il head) ,(unparse-tree-il tail)))
(($ <let> src names gensyms vals body)
`(let ,names ,gensyms ,(map unparse-tree-il vals) ,(unparse-tree-il body)))
(($ <letrec> src in-order? names gensyms vals body)
`(,(if in-order? 'letrec* 'letrec) ,names ,gensyms
,(map unparse-tree-il vals) ,(unparse-tree-il body)))
(($ <fix> src names gensyms vals body)
`(fix ,names ,gensyms ,(map unparse-tree-il vals) ,(unparse-tree-il body)))
(($ <let-values> src exp body)
`(let-values ,(unparse-tree-il exp) ,(unparse-tree-il body)))
(($ <prompt> src escape-only? tag body handler)
`(prompt ,escape-only?
,(unparse-tree-il tag)
,(unparse-tree-il body)
,(unparse-tree-il handler)))
(($ <abort> src tag args tail)
`(abort ,(unparse-tree-il tag) ,(map unparse-tree-il args)
,(unparse-tree-il tail)))))
(define* (tree-il->scheme e #:optional (env #f) (opts '()))
(values ((@ (language scheme decompile-tree-il)
decompile-tree-il)
e env opts)))
(define-syntax-rule (make-tree-il-folder seed ...)
(lambda (tree down up seed ...)
(define (fold-values proc exps seed ...)
(if (null? exps)
(values seed ...)
(let-values (((seed ...) (proc (car exps) seed ...)))
(fold-values proc (cdr exps) seed ...))))
(let foldts ((tree tree) (seed seed) ...)
(let*-values
(((seed ...) (down tree seed ...))
((seed ...)
(match tree
(($ <lexical-set> src name gensym exp)
(foldts exp seed ...))
(($ <module-set> src mod name public? exp)
(foldts exp seed ...))
(($ <toplevel-set> src name exp)
(foldts exp seed ...))
(($ <toplevel-define> src name exp)
(foldts exp seed ...))
(($ <conditional> src test consequent alternate)
(let*-values (((seed ...) (foldts test seed ...))
((seed ...) (foldts consequent seed ...)))
(foldts alternate seed ...)))
(($ <call> src proc args)
(let-values (((seed ...) (foldts proc seed ...)))
(fold-values foldts args seed ...)))
(($ <primcall> src name args)
(fold-values foldts args seed ...))
(($ <seq> src head tail)
(let-values (((seed ...) (foldts head seed ...)))
(foldts tail seed ...)))
(($ <lambda> src meta body)
(if body
(foldts body seed ...)
(values seed ...)))
(($ <lambda-case> src req opt rest kw inits gensyms body
alternate)
(let-values (((seed ...) (fold-values foldts inits seed ...)))
(if alternate
(let-values (((seed ...) (foldts body seed ...)))
(foldts alternate seed ...))
(foldts body seed ...))))
(($ <let> src names gensyms vals body)
(let*-values (((seed ...) (fold-values foldts vals seed ...)))
(foldts body seed ...)))
(($ <letrec> src in-order? names gensyms vals body)
(let*-values (((seed ...) (fold-values foldts vals seed ...)))
(foldts body seed ...)))
(($ <fix> src names gensyms vals body)
(let*-values (((seed ...) (fold-values foldts vals seed ...)))
(foldts body seed ...)))
(($ <let-values> src exp body)
(let*-values (((seed ...) (foldts exp seed ...)))
(foldts body seed ...)))
(($ <prompt> src escape-only? tag body handler)
(let*-values (((seed ...) (foldts tag seed ...))
((seed ...) (foldts body seed ...)))
(foldts handler seed ...)))
(($ <abort> src tag args tail)
(let*-values (((seed ...) (foldts tag seed ...))
((seed ...) (fold-values foldts args seed ...)))
(foldts tail seed ...)))
(_
(values seed ...)))))
(up tree seed ...)))))
(define (tree-il-fold down up seed tree)
"Traverse TREE, calling DOWN before visiting a sub-tree, and UP when
after visiting it. Each of these procedures is invoked as `(PROC TREE
SEED)', where TREE is the sub-tree considered and SEED is the current
result, intially seeded with SEED.
This is an implementation of `foldts' as described by Andy Wingo in
``Applications of fold to XML transformation''."
;; Multi-valued fold naturally puts the seeds at the end, whereas
;; normal fold puts the traversable at the end. Adapt to the expected
;; argument order.
((make-tree-il-folder tree) tree down up seed))
(define (pre-post-order pre post x)
(define (elts-eq? a b)
(or (null? a)
(and (eq? (car a) (car b))
(elts-eq? (cdr a) (cdr b)))))
(let lp ((x x))
(post
(let ((x (pre x)))
(match x
((or ($ <void>)
($ <const>)
($ <primitive-ref>)
($ <lexical-ref>)
($ <module-ref>)
($ <toplevel-ref>))
x)
(($ <lexical-set> src name gensym exp)
(let ((exp* (lp exp)))
(if (eq? exp exp*)
x
(make-lexical-set src name gensym exp*))))
(($ <module-set> src mod name public? exp)
(let ((exp* (lp exp)))
(if (eq? exp exp*)
x
(make-module-set src mod name public? exp*))))
(($ <toplevel-set> src name exp)
(let ((exp* (lp exp)))
(if (eq? exp exp*)
x
(make-toplevel-set src name exp*))))
(($ <toplevel-define> src name exp)
(let ((exp* (lp exp)))
(if (eq? exp exp*)
x
(make-toplevel-define src name exp*))))
(($ <conditional> src test consequent alternate)
(let ((test* (lp test))
(consequent* (lp consequent))
(alternate* (lp alternate)))
(if (and (eq? test test*)
(eq? consequent consequent*)
(eq? alternate alternate*))
x
(make-conditional src test* consequent* alternate*))))
(($ <call> src proc args)
(let ((proc* (lp proc))
(args* (map lp args)))
(if (and (eq? proc proc*)
(elts-eq? args args*))
x
(make-call src proc* args*))))
(($ <primcall> src name args)
(let ((args* (map lp args)))
(if (elts-eq? args args*)
x
(make-primcall src name args*))))
(($ <seq> src head tail)
(let ((head* (lp head))
(tail* (lp tail)))
(if (and (eq? head head*)
(eq? tail tail*))
x
(make-seq src head* tail*))))
(($ <lambda> src meta body)
(let ((body* (and body (lp body))))
(if (eq? body body*)
x
(make-lambda src meta body*))))
(($ <lambda-case> src req opt rest kw inits gensyms body alternate)
(let ((inits* (map lp inits))
(body* (lp body))
(alternate* (and alternate (lp alternate))))
(if (and (elts-eq? inits inits*)
(eq? body body*)
(eq? alternate alternate*))
x
(make-lambda-case src req opt rest kw inits* gensyms body*
alternate*))))
(($ <let> src names gensyms vals body)
(let ((vals* (map lp vals))
(body* (lp body)))
(if (and (elts-eq? vals vals*)
(eq? body body*))
x
(make-let src names gensyms vals* body*))))
(($ <letrec> src in-order? names gensyms vals body)
(let ((vals* (map lp vals))
(body* (lp body)))
(if (and (elts-eq? vals vals*)
(eq? body body*))
x
(make-letrec src in-order? names gensyms vals* body*))))
(($ <fix> src names gensyms vals body)
(let ((vals* (map lp vals))
(body* (lp body)))
(if (and (elts-eq? vals vals*)
(eq? body body*))
x
(make-fix src names gensyms vals* body*))))
(($ <let-values> src exp body)
(let ((exp* (lp exp))
(body* (lp body)))
(if (and (eq? exp exp*)
(eq? body body*))
x
(make-let-values src exp* body*))))
(($ <prompt> src escape-only? tag body handler)
(let ((tag* (lp tag))
(body* (lp body))
(handler* (lp handler)))
(if (and (eq? tag tag*)
(eq? body body*)
(eq? handler handler*))
x
(make-prompt src escape-only? tag* body* handler*))))
(($ <abort> src tag args tail)
(let ((tag* (lp tag))
(args* (map lp args))
(tail* (lp tail)))
(if (and (eq? tag tag*)
(elts-eq? args args*)
(eq? tail tail*))
x
(make-abort src tag* args* tail*)))))))))
(define (post-order f x)
(pre-post-order (lambda (x) x) f x))
(define (pre-order f x)
(pre-post-order f (lambda (x) x) x))
;; FIXME: We should have a better primitive than this.
(define (struct-nfields x)
(/ (string-length (symbol->string (struct-layout x))) 2))
(define (tree-il=? a b)
(cond
((struct? a)
(and (struct? b)
(eq? (struct-vtable a) (struct-vtable b))
;; Assume that all structs are tree-il, so we skip over the
;; src slot.
(let lp ((n (1- (struct-nfields a))))
(or (zero? n)
(and (tree-il=? (struct-ref a n) (struct-ref b n))
(lp (1- n)))))))
((pair? a)
(and (pair? b)
(tree-il=? (car a) (car b))
(tree-il=? (cdr a) (cdr b))))
(else
(equal? a b))))
(define-syntax hash-bits
(make-variable-transformer
(lambda (x)
(syntax-case x ()
(var
(identifier? #'var)
(logcount most-positive-fixnum))))))
(define (tree-il-hash exp)
(let ((hash-depth 4)
(hash-width 3))
(define (hash-exp exp depth)
(define (rotate x bits)
(logior (ash x (- bits))
(ash (logand x (1- (ash 1 bits))) (- hash-bits bits))))
(define (mix h1 h2)
(logxor h1 (rotate h2 8)))
(define (hash-struct s)
(let ((len (struct-nfields s))
(h (hashq (struct-vtable s) most-positive-fixnum)))
(if (zero? depth)
h
(let lp ((i (max (- len hash-width) 1)) (h h))
(if (< i len)
(lp (1+ i) (mix (hash-exp (struct-ref s i) (1+ depth)) h))
h)))))
(define (hash-list l)
(let ((h (hashq 'list most-positive-fixnum)))
(if (zero? depth)
h
(let lp ((l l) (width 0) (h h))
(if (< width hash-width)
(lp (cdr l) (1+ width)
(mix (hash-exp (car l) (1+ depth)) h))
h)))))
(cond
((struct? exp) (hash-struct exp))
((list? exp) (hash-list exp))
(else (hash exp most-positive-fixnum))))
(hash-exp exp 0)))