1 ;;;; optimizers for list and sequence functions
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
14 ;;;; mapping onto lists: the MAPFOO functions
16 (defun mapfoo-transform (fn arglists accumulate take-car)
17 (collect ((do-clauses)
20 (let ((n-first (gensym)))
21 (dolist (a (if accumulate
23 `(,n-first ,@(rest arglists))))
25 (do-clauses `(,v ,a (cdr ,v)))
27 (args-to-fn (if take-car `(car ,v) v))))
29 (let ((call `(funcall ,fn . ,(args-to-fn)))
30 (endtest `(or ,@(tests))))
34 (map-result (gensym)))
35 `(let ((,map-result (list nil)))
36 (do-anonymous ((,temp ,map-result) . ,(do-clauses))
37 (,endtest (cdr ,map-result))
38 (setq ,temp (last (nconc ,temp ,call)))))))
41 (map-result (gensym)))
42 `(let ((,map-result (list nil)))
43 (do-anonymous ((,temp ,map-result) . ,(do-clauses))
44 (,endtest (cdr ,map-result))
45 (rplacd ,temp (setq ,temp (list ,call)))))))
47 `(let ((,n-first ,(first arglists)))
48 (do-anonymous ,(do-clauses)
49 (,endtest ,n-first) ,call))))))))
51 (define-source-transform mapc (function list &rest more-lists)
52 (mapfoo-transform function (cons list more-lists) nil t))
54 (define-source-transform mapcar (function list &rest more-lists)
55 (mapfoo-transform function (cons list more-lists) :list t))
57 (define-source-transform mapcan (function list &rest more-lists)
58 (mapfoo-transform function (cons list more-lists) :nconc t))
60 (define-source-transform mapl (function list &rest more-lists)
61 (mapfoo-transform function (cons list more-lists) nil nil))
63 (define-source-transform maplist (function list &rest more-lists)
64 (mapfoo-transform function (cons list more-lists) :list nil))
66 (define-source-transform mapcon (function list &rest more-lists)
67 (mapfoo-transform function (cons list more-lists) :nconc nil))
69 ;;;; mapping onto sequences: the MAP function
71 ;;; MAP is %MAP plus a check to make sure that any length specified in
72 ;;; the result type matches the actual result. We also wrap it in a
73 ;;; TRULY-THE for the most specific type we can determine.
74 (deftransform map ((result-type-arg fun &rest seqs) * * :node node)
75 (let* ((seq-names (make-gensym-list (length seqs)))
76 (bare `(%map result-type-arg fun ,@seq-names))
77 (constant-result-type-arg-p (constant-continuation-p result-type-arg))
78 ;; what we know about the type of the result. (Note that the
79 ;; "result type" argument is not necessarily the type of the
80 ;; result, since NIL means the result has NULL type.)
81 (result-type (if (not constant-result-type-arg-p)
83 (let ((result-type-arg-value
84 (continuation-value result-type-arg)))
85 (if (null result-type-arg-value)
87 result-type-arg-value)))))
88 `(lambda (result-type-arg fun ,@seq-names)
89 (truly-the ,result-type
90 ,(cond ((policy node (> speed safety))
92 ((not constant-result-type-arg-p)
93 `(sequence-of-checked-length-given-type ,bare
96 (let ((result-ctype (specifier-type result-type)))
97 (if (array-type-p result-ctype)
98 (let* ((dims (array-type-dimensions result-ctype))
102 `(vector-of-checked-length-given-length ,bare
106 ;;; Try to compile %MAP efficiently when we can determine sequence
107 ;;; argument types at compile time.
109 ;;; Note: This transform was written to allow open coding of
110 ;;; quantifiers by expressing them in terms of (MAP NIL ..). For
111 ;;; non-NIL values of RESULT-TYPE, it's still useful, but not
112 ;;; necessarily as efficient as possible. In particular, it will be
113 ;;; inefficient when RESULT-TYPE is a SIMPLE-ARRAY with specialized
114 ;;; numeric element types. It should be straightforward to make it
115 ;;; handle that case more efficiently, but it's left as an exercise to
116 ;;; the reader, because the code is complicated enough already and I
117 ;;; don't happen to need that functionality right now. -- WHN 20000410
118 (deftransform %map ((result-type fun &rest seqs) * * :policy (>= speed space))
120 (unless seqs (abort-ir1-transform "no sequence args"))
121 (unless (constant-continuation-p result-type)
122 (give-up-ir1-transform "RESULT-TYPE argument not constant"))
123 (labels (;; 1-valued SUBTYPEP, fails unless second value of SUBTYPEP is true
124 (fn-1subtypep (fn x y)
125 (multiple-value-bind (subtype-p valid-p) (funcall fn x y)
128 (give-up-ir1-transform
129 "can't analyze sequence type relationship"))))
130 (1subtypep (x y) (fn-1subtypep #'sb!xc:subtypep x y))
131 (1csubtypep (x y) (fn-1subtypep #'csubtypep x y))
133 (let ((ctype (continuation-type seq)))
134 (cond ((1csubtypep ctype (specifier-type 'vector)) 'vector)
135 ((1csubtypep ctype (specifier-type 'list)) 'list)
137 (give-up-ir1-transform
138 "can't determine sequence argument type"))))))
139 (let* ((result-type-value (continuation-value result-type))
140 (result-supertype (cond ((null result-type-value) 'null)
141 ((1subtypep result-type-value 'vector)
143 ((1subtypep result-type-value 'list)
146 (give-up-ir1-transform
147 "can't determine result type"))))
148 (seq-supertypes (mapcar #'seq-supertype seqs)))
149 (cond ((and result-type-value (= 1 (length seqs)))
150 ;; The consing arity-1 cases can be implemented
151 ;; reasonably efficiently as function calls, and the cost
152 ;; of consing should be significantly larger than
153 ;; function call overhead, so we always compile these
154 ;; cases as full calls regardless of speed-versus-space
155 ;; optimization policy.
156 (cond ((subtypep 'list result-type-value)
157 '(apply #'%map-to-list-arity-1 fun seqs))
158 (;; (This one can be inefficient due to COERCE, but
159 ;; the current open-coded implementation has the
161 (subtypep result-type-value 'vector)
162 `(coerce (apply #'%map-to-simple-vector-arity-1 fun seqs)
163 ',result-type-value))
164 (t (bug "impossible (?) sequence type"))))
166 (let* ((seq-args (make-gensym-list (length seqs)))
168 (mapcar (lambda (seq-arg seq-supertype)
169 (let ((i (gensym "I")))
171 (vector `(,i 0 (1+ ,i)))
172 (list `(,i ,seq-arg (rest ,i))))))
173 seq-args seq-supertypes))
174 (indices (mapcar #'first index-bindingoids))
175 (index-decls (mapcar (lambda (index seq-supertype)
176 `(type ,(ecase seq-supertype
180 indices seq-supertypes))
181 (tests (mapcar (lambda (seq-arg seq-supertype index)
183 (vector `(>= ,index (length ,seq-arg)))
184 (list `(endp ,index))))
185 seq-args seq-supertypes indices))
186 (values (mapcar (lambda (seq-arg seq-supertype index)
188 (vector `(aref ,seq-arg ,index))
189 (list `(first ,index))))
190 seq-args seq-supertypes indices)))
191 (multiple-value-bind (push-dacc final-result)
192 (ecase result-supertype
193 (null (values nil nil))
194 (list (values `(push dacc acc) `(nreverse acc)))
195 (vector (values `(push dacc acc)
196 `(coerce (nreverse acc)
197 ',result-type-value))))
198 ;; (We use the same idiom, of returning a LAMBDA from
199 ;; DEFTRANSFORM, as is used in the DEFTRANSFORMs for
200 ;; FUNCALL and ALIEN-FUNCALL, and for the same
201 ;; reason: we need to get the runtime values of each
202 ;; of the &REST vars.)
203 `(lambda (result-type fun ,@seq-args)
204 (declare (ignore result-type))
205 (do ((really-fun (%coerce-callable-to-fun fun))
210 (declare ,@index-decls)
211 (declare (type list acc))
212 (declare (ignorable acc))
213 (let ((dacc (funcall really-fun ,@values)))
214 (declare (ignorable dacc))
217 (deftransform elt ((s i) ((simple-array * (*)) *) *)
220 (deftransform elt ((s i) (list *) *)
223 (deftransform %setelt ((s i v) ((simple-array * (*)) * *) *)
226 (deftransform %setelt ((s i v) (list * *))
227 '(setf (car (nthcdr i s)) v))
229 (macrolet ((def (name)
230 `(deftransform ,name ((e l &key (test #'eql)) * *
232 (unless (constant-continuation-p l)
233 (give-up-ir1-transform))
235 (let ((val (continuation-value l)))
238 (and (>= speed space)
239 (<= (length val) 5))))
240 (give-up-ir1-transform))
244 `(if (funcall test e ',(car els))
252 ;;; FIXME: We have rewritten the original code that used DOLIST to this
253 ;;; more natural MACROLET. However, the original code suggested that when
254 ;;; this was done, a few bytes could be saved by a call to a shared
255 ;;; function. This remains to be done.
256 (macrolet ((def (fun eq-fun)
257 `(deftransform ,fun ((item list &key test) (t list &rest t) *)
259 ;; FIXME: The scope of this transformation could be
260 ;; widened somewhat, letting it work whenever the test is
261 ;; 'EQL and we know from the type of ITEM that it #'EQ
262 ;; works like #'EQL on it. (E.g. types FIXNUM, CHARACTER,
264 ;; If TEST is EQ, apply transform, else
265 ;; if test is not EQL, then give up on transform, else
266 ;; if ITEM is not a NUMBER or is a FIXNUM, apply
267 ;; transform, else give up on transform.
269 (unless (continuation-fun-is test '(eq))
270 (give-up-ir1-transform)))
271 ((types-equal-or-intersect (continuation-type item)
272 (specifier-type 'number))
273 (give-up-ir1-transform "Item might be a number.")))
274 `(,',eq-fun item list))))
279 (deftransform delete-if ((pred list) (t list))
281 '(do ((x list (cdr x))
284 (cond ((funcall pred (car x))
287 (rplacd splice (cdr x))))
288 (T (setq splice x)))))
290 (deftransform fill ((seq item &key (start 0) (end (length seq)))
291 (vector t &key (:start t) (:end index))
293 :policy (> speed space))
295 (let ((element-type (upgraded-element-type-specifier-or-give-up seq)))
297 `(with-array-data ((data seq)
300 (declare (type (simple-array ,element-type 1) data))
301 (declare (type fixnum start end))
302 (do ((i start (1+ i)))
304 (declare (type index i))
305 ;; WITH-ARRAY-DATA did our range checks once and for all, so
306 ;; it'd be wasteful to check again on every AREF...
307 (declare (optimize (safety 0)))
308 (setf (aref data i) item)))
309 ;; ... though we still need to check that the new element can fit
310 ;; into the vector in safe code. -- CSR, 2002-07-05
311 `((declare (type ,element-type item))))))
315 ;;; Return true if CONT's only use is a non-NOTINLINE reference to a
316 ;;; global function with one of the specified NAMES.
317 (defun continuation-fun-is (cont names)
318 (declare (type continuation cont) (list names))
319 (let ((use (continuation-use cont)))
321 (let ((leaf (ref-leaf use)))
322 (and (global-var-p leaf)
323 (eq (global-var-kind leaf) :global-function)
324 (not (null (member (leaf-source-name leaf) names
325 :test #'equal))))))))
327 ;;; If CONT is a constant continuation, the return the constant value.
328 ;;; If it is null, then return default, otherwise quietly give up the
331 ;;; ### Probably should take an ARG and flame using the NAME.
332 (defun constant-value-or-lose (cont &optional default)
333 (declare (type (or continuation null) cont))
334 (cond ((not cont) default)
335 ((constant-continuation-p cont)
336 (continuation-value cont))
338 (give-up-ir1-transform))))
340 ;;; FIXME: Why is this code commented out? (Why *was* it commented
341 ;;; out? We inherited this situation from cmucl-2.4.8, with no
342 ;;; explanation.) Should we just delete this code?
344 ;;; This is a frob whose job it is to make it easier to pass around
345 ;;; the arguments to IR1 transforms. It bundles together the name of
346 ;;; the argument (which should be referenced in any expansion), and
347 ;;; the continuation for that argument (or NIL if unsupplied.)
348 (defstruct (arg (:constructor %make-arg (name cont))
350 (name nil :type symbol)
351 (cont nil :type (or continuation null)))
352 (defmacro make-arg (name)
353 `(%make-arg ',name ,name))
355 ;;; If Arg is null or its CONT is null, then return Default, otherwise
356 ;;; return Arg's NAME.
357 (defun default-arg (arg default)
358 (declare (type (or arg null) arg))
359 (if (and arg (arg-cont arg))
363 ;;; If Arg is null or has no CONT, return the default. Otherwise, Arg's
364 ;;; CONT must be a constant continuation whose value we return. If not, we
366 (defun arg-constant-value (arg default)
367 (declare (type (or arg null) arg))
368 (if (and arg (arg-cont arg))
369 (let ((cont (arg-cont arg)))
370 (unless (constant-continuation-p cont)
371 (give-up-ir1-transform "Argument is not constant: ~S."
373 (continuation-value from-end))
376 ;;; If Arg is a constant and is EQL to X, then return T, otherwise NIL. If
377 ;;; Arg is NIL or its CONT is NIL, then compare to the default.
378 (defun arg-eql (arg default x)
379 (declare (type (or arg null) x))
380 (if (and arg (arg-cont arg))
381 (let ((cont (arg-cont arg)))
382 (and (constant-continuation-p cont)
383 (eql (continuation-value cont) x)))
386 (defstruct (iterator (:copier nil))
387 ;; The kind of iterator.
388 (kind nil (member :normal :result))
389 ;; A list of LET* bindings to create the initial state.
390 (binds nil :type list)
391 ;; A list of declarations for Binds.
392 (decls nil :type list)
393 ;; A form that returns the current value. This may be set with SETF to set
394 ;; the current value.
395 (current (error "Must specify CURRENT."))
396 ;; In a :NORMAL iterator, a form that tests whether there is a current value.
398 ;; In a :RESULT iterator, a form that truncates the result at the current
399 ;; position and returns it.
401 ;; A form that returns the initial total number of values. The result is
402 ;; undefined after NEXT has been evaluated.
403 (length (error "Must specify LENGTH."))
404 ;; A form that advances the state to the next value. It is an error to call
405 ;; this when the iterator is Done.
406 (next (error "Must specify NEXT.")))
408 ;;; Type of an index var that can go negative (in the from-end case.)
409 (deftype neg-index ()
410 `(integer -1 ,most-positive-fixnum))
412 ;;; Return an ITERATOR structure describing how to iterate over an arbitrary
413 ;;; sequence. Sequence is a variable bound to the sequence, and Type is the
414 ;;; type of the sequence. If true, INDEX is a variable that should be bound to
415 ;;; the index of the current element in the sequence.
417 ;;; If we can't tell whether the sequence is a list or a vector, or whether
418 ;;; the iteration is forward or backward, then GIVE-UP.
419 (defun make-sequence-iterator (sequence type &key start end from-end index)
420 (declare (symbol sequence) (type ctype type)
421 (type (or arg null) start end from-end)
422 (type (or symbol null) index))
423 (let ((from-end (arg-constant-value from-end nil)))
424 (cond ((csubtypep type (specifier-type 'vector))
425 (let* ((n-stop (gensym))
426 (n-idx (or index (gensym)))
427 (start (default-arg 0 start))
428 (end (default-arg `(length ,sequence) end)))
431 :binds `((,n-idx ,(if from-end `(1- ,end) ,start))
432 (,n-stop ,(if from-end `(1- ,start) ,end)))
433 :decls `((type neg-index ,n-idx ,n-stop))
434 :current `(aref ,sequence ,n-idx)
435 :done `(,(if from-end '<= '>=) ,n-idx ,n-stop)
437 ,(if from-end `(1- ,n-idx) `(1+ ,n-idx)))
440 `(- ,n-stop ,n-idx)))))
441 ((csubtypep type (specifier-type 'list))
442 (let* ((n-stop (if (and end (not from-end)) (gensym) nil))
444 (start-p (not (arg-eql start 0 0)))
445 (end-p (not (arg-eql end nil nil)))
446 (start (default-arg start 0))
447 (end (default-arg end nil)))
451 (if (or start-p end-p)
452 `(nreverse (subseq ,sequence ,start
453 ,@(when end `(,end))))
454 `(reverse ,sequence))
456 `(nthcdr ,start ,sequence)
459 `((,n-stop (nthcdr (the index
463 `((,index ,(if from-end `(1- ,end) start)))))
465 :decls `((list ,n-current ,n-end)
466 ,@(when index `((type neg-index ,index))))
467 :current `(car ,n-current)
468 :done `(eq ,n-current ,n-stop)
469 :length `(- ,(or end `(length ,sequence)) ,start)
471 (setq ,n-current (cdr ,n-current))
478 (give-up-ir1-transform
479 "can't tell whether sequence is a list or a vector")))))
481 ;;; Make an iterator used for constructing result sequences. Name is a
482 ;;; variable to be bound to the result sequence. Type is the type of result
483 ;;; sequence to make. Length is an expression to be evaluated to get the
484 ;;; maximum length of the result (not evaluated in list case.)
485 (defun make-result-sequence-iterator (name type length)
486 (declare (symbol name) (type ctype type))
488 ;;; Define each NAME as a local macro that will call the value of the
489 ;;; function arg with the given arguments. If the argument isn't known to be a
490 ;;; function, give them an efficiency note and reference a coerced version.
491 (defmacro coerce-funs (specs &body body)
493 "COERCE-FUNCTIONS ({(Name Fun-Arg Default)}*) Form*"
497 `(let ((body (progn ,@body))
498 (n-fun (arg-name ,(second spec)))
499 (fun-cont (arg-cont ,(second spec))))
500 (cond ((not fun-cont)
501 `(macrolet ((,',(first spec) (&rest args)
502 `(,',',(third spec) ,@args)))
504 ((not (csubtypep (continuation-type fun-cont)
505 (specifier-type 'function)))
506 (when (policy *compiler-error-context*
507 (> speed inhibit-warnings))
509 "~S may not be a function, so must coerce at run-time."
511 (once-only ((n-fun `(if (functionp ,n-fun)
513 (symbol-function ,n-fun))))
514 `(macrolet ((,',(first spec) (&rest args)
515 `(funcall ,',n-fun ,@args)))
518 `(macrolet ((,',(first spec) (&rest args)
519 `(funcall ,',n-fun ,@args)))
522 ;;; Wrap code around the result of the body to define Name as a local macro
523 ;;; that returns true when its arguments satisfy the test according to the Args
524 ;;; Test and Test-Not. If both Test and Test-Not are supplied, abort the
526 (defmacro with-sequence-test ((name test test-not) &body body)
527 `(let ((not-p (arg-cont ,test-not)))
528 (when (and (arg-cont ,test) not-p)
529 (abort-ir1-transform "Both ~S and ~S were supplied."
531 (arg-name ,test-not)))
532 (coerce-funs ((,name (if not-p ,test-not ,test) eql))
536 ;;;; hairy sequence transforms
538 ;;; FIXME: no hairy sequence transforms in SBCL?
540 ;;;; string operations
542 ;;; We transform the case-sensitive string predicates into a non-keyword
543 ;;; version. This is an IR1 transform so that we don't have to worry about
544 ;;; changing the order of evaluation.
545 (macrolet ((def (fun pred*)
546 `(deftransform ,fun ((string1 string2 &key (start1 0) end1
549 `(,',pred* string1 string2 start1 end1 start2 end2))))
550 (def string< string<*)
551 (def string> string>*)
552 (def string<= string<=*)
553 (def string>= string>=*)
554 (def string= string=*)
555 (def string/= string/=*))
557 ;;; Return a form that tests the free variables STRING1 and STRING2
558 ;;; for the ordering relationship specified by LESSP and EQUALP. The
559 ;;; start and end are also gotten from the environment. Both strings
560 ;;; must be SIMPLE-STRINGs.
561 (macrolet ((def (name lessp equalp)
562 `(deftransform ,name ((string1 string2 start1 end1 start2 end2)
563 (simple-string simple-string t t t t) *)
564 `(let* ((end1 (if (not end1) (length string1) end1))
565 (end2 (if (not end2) (length string2) end2))
566 (index (sb!impl::%sp-string-compare
567 string1 start1 end1 string2 start2 end2)))
569 (cond ((= index ,(if ',lessp 'end1 'end2)) index)
570 ((= index ,(if ',lessp 'end2 'end1)) nil)
571 ((,(if ',lessp 'char< 'char>)
572 (schar string1 index)
581 ,(if ',equalp 'end1 nil))))))
584 (def string>* nil nil)
585 (def string>=* nil t))
587 (macrolet ((def (name result-fun)
588 `(deftransform ,name ((string1 string2 start1 end1 start2 end2)
589 (simple-string simple-string t t t t) *)
591 (sb!impl::%sp-string-compare
592 string1 start1 (or end1 (length string1))
593 string2 start2 (or end2 (length string2)))))))
595 (def string/=* identity))
598 ;;;; string-only transforms for sequence functions
600 ;;;; Note: CMU CL had more of these, including transforms for
601 ;;;; functions which cons. In SBCL, we've gotten rid of most of the
602 ;;;; transforms for functions which cons, since our GC overhead is
603 ;;;; sufficiently large that it doesn't seem worth it to try to
604 ;;;; economize on function call overhead or on the overhead of runtime
605 ;;;; type dispatch in AREF. The exception is CONCATENATE, since
606 ;;;; a full call to CONCATENATE would have to look up the sequence
607 ;;;; type, which can be really slow.
609 ;;;; FIXME: It would be nicer for these transforms to work for any
610 ;;;; calls when all arguments are vectors with the same element type,
611 ;;;; rather than restricting them to STRINGs only.
613 ;;; Moved here from generic/vm-tran.lisp to satisfy clisp
615 ;;; FIXME: It would be good to implement SB!XC:DEFCONSTANT, and use
616 ;;; use that here, so that the compiler is born knowing this value.
617 ;;; FIXME: Add a comment telling whether this holds for all vectors
618 ;;; or only for vectors based on simple arrays (non-adjustable, etc.).
619 (def!constant vector-data-bit-offset
620 (* sb!vm:vector-data-offset sb!vm:n-word-bits))
622 ;;; FIXME: Shouldn't we be testing for legality of
623 ;;; * START1, START2, END1, and END2 indices?
624 ;;; * size of copied string relative to destination string?
625 ;;; (Either there should be tests conditional on SAFETY>=SPEED, or
626 ;;; the transform should be conditional on SPEED>SAFETY.)
628 ;;; FIXME: Also, the transform should probably be dependent on
630 (deftransform replace ((string1 string2 &key (start1 0) (start2 0)
632 (simple-string simple-string &rest t))
634 (declare (optimize (safety 0)))
635 (bit-bash-copy string2
637 (+ (the index (* start2 sb!vm:n-byte-bits))
638 ,vector-data-bit-offset))
641 (+ (the index (* start1 sb!vm:n-byte-bits))
642 ,vector-data-bit-offset))
644 (* (min (the index (- (or end1 (length string1))
646 (the index (- (or end2 (length string2))
651 ;;; FIXME: It seems as though it should be possible to make a DEFUN
652 ;;; %CONCATENATE (with a DEFTRANSFORM to translate constant RTYPE to
653 ;;; CTYPE before calling %CONCATENATE) which is comparably efficient,
654 ;;; at least once DYNAMIC-EXTENT works.
655 (deftransform concatenate ((rtype &rest sequences)
656 (t &rest simple-string)
662 (dolist (seq sequences)
663 (declare (ignorable seq))
664 (let ((n-seq (gensym))
667 (lets `(,n-length (the index (* (length ,n-seq) sb!vm:n-byte-bits))))
668 (all-lengths n-length)
669 (forms `(bit-bash-copy ,n-seq ,vector-data-bit-offset
672 (forms `(setq start (+ start ,n-length)))))
673 `(lambda (rtype ,@(args))
674 (declare (ignore rtype))
676 (res (make-string (truncate (the index (+ ,@(all-lengths)))
678 (start ,vector-data-bit-offset))
679 (declare (type index start ,@(all-lengths)))
683 ;;;; CONS accessor DERIVE-TYPE optimizers
685 (defoptimizer (car derive-type) ((cons))
686 (let ((type (continuation-type cons))
687 (null-type (specifier-type 'null)))
688 (cond ((eq type null-type)
691 (cons-type-car-type type)))))
693 (defoptimizer (cdr derive-type) ((cons))
694 (let ((type (continuation-type cons))
695 (null-type (specifier-type 'null)))
696 (cond ((eq type null-type)
699 (cons-type-cdr-type type)))))
701 ;;;; FIND, POSITION, and their -IF and -IF-NOT variants
703 ;;; We want to make sure that %FIND-POSITION is inline-expanded into
704 ;;; %FIND-POSITION-IF only when %FIND-POSITION-IF has an inline
705 ;;; expansion, so we factor out the condition into this function.
706 (defun check-inlineability-of-find-position-if (sequence from-end)
707 (let ((ctype (continuation-type sequence)))
708 (cond ((csubtypep ctype (specifier-type 'vector))
709 ;; It's not worth trying to inline vector code unless we
710 ;; know a fair amount about it at compile time.
711 (upgraded-element-type-specifier-or-give-up sequence)
712 (unless (constant-continuation-p from-end)
713 (give-up-ir1-transform
714 "FROM-END argument value not known at compile time")))
715 ((csubtypep ctype (specifier-type 'list))
716 ;; Inlining on lists is generally worthwhile.
719 (give-up-ir1-transform
720 "sequence type not known at compile time")))))
722 ;;; %FIND-POSITION-IF and %FIND-POSITION-IF-NOT for LIST data
723 (macrolet ((def (name condition)
724 `(deftransform ,name ((predicate sequence from-end start end key)
725 (function list t t t function)
727 :policy (> speed space)
733 (declare (type index index))
734 (dolist (i sequence (values find position))
735 (let ((key-i (funcall key i)))
736 (when (and end (>= index end))
737 (return (values find position)))
738 (when (>= index start)
739 (,',condition (funcall predicate key-i)
740 ;; This hack of dealing with non-NIL
741 ;; FROM-END for list data by iterating
742 ;; forward through the list and keeping
743 ;; track of the last time we found a match
744 ;; might be more screwy than what the user
745 ;; expects, but it seems to be allowed by
746 ;; the ANSI standard. (And if the user is
747 ;; screwy enough to ask for FROM-END
748 ;; behavior on list data, turnabout is
751 ;; It's also not enormously efficient,
752 ;; calling PREDICATE and KEY more often
753 ;; than necessary; but all the
754 ;; alternatives seem to have their own
755 ;; efficiency problems.
759 (return (values i index))))))
761 (def %find-position-if when)
762 (def %find-position-if-not unless))
764 ;;; %FIND-POSITION for LIST data can be expanded into %FIND-POSITION-IF
765 ;;; without loss of efficiency. (I.e., the optimizer should be able
766 ;;; to straighten everything out.)
767 (deftransform %find-position ((item sequence from-end start end key test)
770 :policy (> speed space)
773 '(%find-position-if (let ((test-fun (%coerce-callable-to-fun test)))
774 ;; I'm having difficulty believing I'm
775 ;; reading it right, but as far as I can see,
776 ;; the only guidance that ANSI gives for the
777 ;; order of arguments to asymmetric tests is
778 ;; the character-set dependent example from
779 ;; the definition of FIND,
780 ;; (find #\d "here are some.." :test #'char>)
782 ;; (In ASCII, we have (CHAR> #\d #\SPACE)=>T.)
783 ;; (Neither the POSITION definition page nor
784 ;; section 17.2 ("Rules about Test Functions")
785 ;; seem to consider the possibility of
788 ;; So, judging from the example, we want to
789 ;; do (FUNCALL TEST-FUN ITEM I), because
790 ;; (FUNCALL #'CHAR> #\d #\SPACE)=>T.
792 ;; -- WHN (whose attention was drawn to it by
793 ;; Alexey Dejneka's bug report/fix)
795 (funcall test-fun item i)))
800 (%coerce-callable-to-fun key)))
802 ;;; The inline expansions for the VECTOR case are saved as macros so
803 ;;; that we can share them between the DEFTRANSFORMs and the default
804 ;;; cases in the DEFUNs. (This isn't needed for the LIST case, because
805 ;;; the DEFTRANSFORMs for LIST are less choosy about when to expand.)
806 (defun %find-position-or-find-position-if-vector-expansion (sequence-arg
812 (let ((offset (gensym "OFFSET"))
813 (block (gensym "BLOCK"))
814 (index (gensym "INDEX"))
815 (n-sequence (gensym "N-SEQUENCE-"))
816 (sequence (gensym "SEQUENCE"))
817 (n-end (gensym "N-END-"))
818 (end (gensym "END-")))
819 `(let ((,n-sequence ,sequence-arg)
821 (with-array-data ((,sequence ,n-sequence :offset-var ,offset)
823 (,end (or ,n-end (length ,n-sequence))))
825 (macrolet ((maybe-return ()
826 '(let ((,element (aref ,sequence ,index)))
830 (- ,index ,offset)))))))
833 ;; (If we aren't fastidious about declaring that
834 ;; INDEX might be -1, then (FIND 1 #() :FROM-END T)
835 ;; can send us off into never-never land, since
836 ;; INDEX is initialized to -1.)
837 of-type index-or-minus-1
838 from (1- ,end) downto ,start do
840 (loop for ,index of-type index from ,start below ,end do
842 (values nil nil))))))
844 (def!macro %find-position-vector-macro (item sequence
845 from-end start end key test)
846 (let ((element (gensym "ELEMENT")))
847 (%find-position-or-find-position-if-vector-expansion
853 ;; (See the LIST transform for a discussion of the correct
854 ;; argument order, i.e. whether the searched-for ,ITEM goes before
855 ;; or after the checked sequence element.)
856 `(funcall ,test ,item (funcall ,key ,element)))))
858 (def!macro %find-position-if-vector-macro (predicate sequence
859 from-end start end key)
860 (let ((element (gensym "ELEMENT")))
861 (%find-position-or-find-position-if-vector-expansion
867 `(funcall ,predicate (funcall ,key ,element)))))
869 (def!macro %find-position-if-not-vector-macro (predicate sequence
870 from-end start end key)
871 (let ((element (gensym "ELEMENT")))
872 (%find-position-or-find-position-if-vector-expansion
878 `(not (funcall ,predicate (funcall ,key ,element))))))
880 ;;; %FIND-POSITION, %FIND-POSITION-IF and %FIND-POSITION-IF-NOT for
882 (deftransform %find-position-if ((predicate sequence from-end start end key)
883 (function vector t t t function)
885 :policy (> speed space)
888 (check-inlineability-of-find-position-if sequence from-end)
889 '(%find-position-if-vector-macro predicate sequence
890 from-end start end key))
892 (deftransform %find-position-if-not ((predicate sequence from-end start end key)
893 (function vector t t t function)
895 :policy (> speed space)
898 (check-inlineability-of-find-position-if sequence from-end)
899 '(%find-position-if-not-vector-macro predicate sequence
900 from-end start end key))
902 (deftransform %find-position ((item sequence from-end start end key test)
903 (t vector t t t function function)
905 :policy (> speed space)
908 (check-inlineability-of-find-position-if sequence from-end)
909 '(%find-position-vector-macro item sequence
910 from-end start end key test))