1 ;;;; This file implements the constraint propagation phase of the
2 ;;;; compiler, which uses global flow analysis to obtain dynamic type
5 ;;;; This software is part of the SBCL system. See the README file for
8 ;;;; This software is derived from the CMU CL system, which was
9 ;;;; written at Carnegie Mellon University and released into the
10 ;;;; public domain. The software is in the public domain and is
11 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
12 ;;;; files for more information.
18 ;;; -- MV-BIND, :ASSIGNMENT
20 ;;; Note: The functions in this file that accept constraint sets are
21 ;;; actually receiving the constraint sets associated with nodes,
22 ;;; blocks, and lambda-vars. It might be make CP easier to understand
23 ;;; and work on if these functions traded in nodes, blocks, and
24 ;;; lambda-vars directly.
28 ;;; -- Constraint propagation badly interacts with bottom-up type
29 ;;; inference. Consider
31 ;;; (defun foo (n &aux (i 42))
32 ;;; (declare (optimize speed))
33 ;;; (declare (fixnum n)
34 ;;; #+nil (type (integer 0) i))
38 ;;; (when (>= i n) (go :exit))
43 ;;; In this case CP cannot even infer that I is of class INTEGER.
45 ;;; -- In the above example if we place the check after SETQ, CP will
46 ;;; fail to infer (< I FIXNUM): it does not understand that this
47 ;;; constraint follows from (TYPEP I (INTEGER 0 0)).
51 ;;; *CONSTRAINT-UNIVERSE* gets bound in IR1-PHASES to a fresh,
52 ;;; zero-length, non-zero-total-size vector-with-fill-pointer.
53 (declaim (type (and vector (not simple-vector)) *constraint-universe*))
54 (defvar *constraint-universe*)
56 (deftype constraint-y () '(or ctype lvar lambda-var constant))
58 (defstruct (constraint
59 (:include sset-element)
60 (:constructor make-constraint (number kind x y not-p))
62 ;; the kind of constraint we have:
65 ;; X is a LAMBDA-VAR and Y is a CTYPE. The value of X is
66 ;; constrained to be of type Y.
69 ;; X is a lambda-var and Y is a CTYPE. The relation holds
70 ;; between X and some object of type Y.
73 ;; X is a LAMBDA-VAR and Y is a LVAR, a LAMBDA-VAR or a CONSTANT.
74 ;; The relation is asserted to hold.
75 (kind nil :type (member typep < > eql))
76 ;; The operands to the relation.
77 (x nil :type lambda-var)
78 (y nil :type constraint-y)
79 ;; If true, negates the sense of the constraint, so the relation
81 (not-p nil :type boolean))
83 ;;; Historically, CMUCL and SBCL have used a sparse set implementation
84 ;;; for which most operations are O(n) (see sset.lisp), but at the
85 ;;; cost of at least a full word of pointer for each constraint set
86 ;;; element. Using bit-vectors instead of pointer structures saves a
87 ;;; lot of space and thus GC time (particularly on 64-bit machines),
88 ;;; and saves time on copy, union, intersection, and difference
89 ;;; operations; but makes iteration slower. Circa September 2008,
90 ;;; switching to bit-vectors gave a modest (5-10%) improvement in real
91 ;;; compile time for most Lisp systems, and as much as 20-30% for some
92 ;;; particularly CP-dependent systems.
94 ;;; It's bad to leave commented code in files, but if some clever
95 ;;; person comes along and makes SSETs better than bit-vectors as sets
96 ;;; for constraint propagation, or if bit-vectors on some XC host
97 ;;; really lose compared to SSETs, here's the conset API as a wrapper
101 (deftype conset () 'sset)
102 (declaim (ftype (sfunction (conset) boolean) conset-empty))
103 (declaim (ftype (sfunction (conset) conset) copy-conset))
104 (declaim (ftype (sfunction (constraint conset) boolean) conset-member))
105 (declaim (ftype (sfunction (constraint conset) boolean) conset-adjoin))
106 (declaim (ftype (sfunction (conset conset) boolean) conset=))
107 (declaim (ftype (sfunction (conset conset) (values)) conset-union))
108 (declaim (ftype (sfunction (conset conset) (values)) conset-intersection))
109 (declaim (ftype (sfunction (conset conset) (values)) conset-difference))
110 (defun make-conset () (make-sset))
111 (defmacro do-conset-elements ((constraint conset &optional result) &body body)
112 `(do-sset-elements (,constraint ,conset ,result) ,@body))
113 (defmacro do-conset-intersection
114 ((constraint conset1 conset2 &optional result) &body body)
115 `(do-conset-elements (,constraint ,conset1 ,result)
116 (when (conset-member ,constraint ,conset2)
118 (defun conset-empty (conset) (sset-empty conset))
119 (defun copy-conset (conset) (copy-sset conset))
120 (defun conset-member (constraint conset) (sset-member constraint conset))
121 (defun conset-adjoin (constraint conset) (sset-adjoin constraint conset))
122 (defun conset= (conset1 conset2) (sset= conset1 conset2))
123 ;; Note: CP doesn't ever care whether union, intersection, and
124 ;; difference change the first set. (This is an important degree of
125 ;; freedom, since some ways of implementing sets lose a great deal
126 ;; when these operations are required to track changes.)
127 (defun conset-union (conset1 conset2)
128 (sset-union conset1 conset2) (values))
129 (defun conset-intersection (conset1 conset2)
130 (sset-intersection conset1 conset2) (values))
131 (defun conset-difference (conset1 conset2)
132 (sset-difference conset1 conset2) (values)))
135 ;; This is performance critical for the compiler, and benefits
136 ;; from the following declarations. Probably you'll want to
137 ;; disable these declarations when debugging consets.
138 (declare #-sb-xc-host (optimize (speed 3) (safety 0) (space 0)))
139 (declaim (inline %constraint-number))
140 (defun %constraint-number (constraint)
141 (sset-element-number constraint))
143 (:constructor make-conset ())
144 (:copier %copy-conset))
146 ;; FIXME: make POWER-OF-TWO-CEILING available earlier?
147 (ash 1 (integer-length (1- (length *constraint-universe*))))
148 :element-type 'bit :initial-element 0)
149 :type simple-bit-vector)
150 ;; Bit-vectors win over lightweight hashes for copy, union,
151 ;; intersection, difference, but lose for iteration if you iterate
152 ;; over the whole vector. Tracking extrema helps a bit.
154 (max 0 :type fixnum))
156 (defmacro do-conset-elements ((constraint conset &optional result) &body body)
157 (with-unique-names (vector index start end
159 #-sb-xc-host constraint-universe-end)
160 (let* ((constraint-universe #+sb-xc-host '*constraint-universe*
161 #-sb-xc-host (sb!xc:gensym "UNIVERSE"))
163 #+sb-xc-host '(progn)
164 #-sb-xc-host `(with-array-data
165 ((,constraint-universe *constraint-universe*)
166 (,ignore 0) (,constraint-universe-end nil)
167 :check-fill-pointer t)
168 (declare (ignore ,ignore))
169 (aver (<= ,end ,constraint-universe-end)))))
170 `(let* ((,vector (conset-vector ,conset))
171 (,start (conset-min ,conset))
172 (,end (min (conset-max ,conset) (length ,vector))))
174 (do ((,index ,start (1+ ,index))) ((>= ,index ,end) ,result)
175 (when (plusp (sbit ,vector ,index))
176 (let ((,constraint (elt ,constraint-universe ,index)))
179 ;; Oddly, iterating just between the maximum of the two sets' minima
180 ;; and the minimum of the sets' maxima slowed down CP.
181 (defmacro do-conset-intersection
182 ((constraint conset1 conset2 &optional result) &body body)
183 `(do-conset-elements (,constraint ,conset1 ,result)
184 (when (conset-member ,constraint ,conset2)
187 (defun conset-empty (conset)
188 (or (= (conset-min conset) (conset-max conset))
189 ;; TODO: I bet FIND on bit-vectors can be optimized, if it
191 (not (find 1 (conset-vector conset)
192 :start (conset-min conset)
193 ;; By inspection, supplying :END here breaks the
194 ;; build with a "full call to
195 ;; DATA-VECTOR-REF-WITH-OFFSET" in the
196 ;; cross-compiler. If that should change, add
197 ;; :end (conset-max conset)
200 (defun copy-conset (conset)
201 (let ((ret (%copy-conset conset)))
202 (setf (conset-vector ret) (copy-seq (conset-vector conset)))
205 (defun %conset-grow (conset new-size)
206 (declare (type index new-size))
207 (setf (conset-vector conset)
208 (replace (the simple-bit-vector
210 (ash 1 (integer-length (1- new-size)))
213 (the simple-bit-vector
214 (conset-vector conset)))))
216 (declaim (inline conset-grow))
217 (defun conset-grow (conset new-size)
218 (declare (type index new-size))
219 (when (< (length (conset-vector conset)) new-size)
220 (%conset-grow conset new-size))
223 (defun conset-member (constraint conset)
224 (let ((number (%constraint-number constraint))
225 (vector (conset-vector conset)))
226 (when (< number (length vector))
227 (plusp (sbit vector number)))))
229 (defun conset-adjoin (constraint conset)
231 (not (conset-member constraint conset))
232 (let ((number (%constraint-number constraint)))
233 (conset-grow conset (1+ number))
234 (setf (sbit (conset-vector conset) number) 1)
235 (setf (conset-min conset) (min number (conset-min conset)))
236 (when (>= number (conset-max conset))
237 (setf (conset-max conset) (1+ number))))))
239 (defun conset= (conset1 conset2)
240 (let* ((vector1 (conset-vector conset1))
241 (vector2 (conset-vector conset2))
242 (length1 (length vector1))
243 (length2 (length vector2)))
244 (if (= length1 length2)
245 ;; When the lengths are the same, we can rely on EQUAL being
246 ;; nicely optimized on bit-vectors.
247 (equal vector1 vector2)
248 (multiple-value-bind (shorter longer)
249 (if (< length1 length2)
250 (values vector1 vector2)
251 (values vector2 vector1))
252 ;; FIXME: make MISMATCH fast on bit-vectors.
253 (dotimes (index (length shorter))
254 (when (/= (sbit vector1 index) (sbit vector2 index))
255 (return-from conset= nil)))
256 (if (find 1 longer :start (length shorter))
261 ((defconsetop (name bit-op)
262 `(defun ,name (conset-1 conset-2)
263 (declare (optimize (speed 3) (safety 0)))
264 (let* ((size-1 (length (conset-vector conset-1)))
265 (size-2 (length (conset-vector conset-2)))
266 (new-size (max size-1 size-2)))
267 (conset-grow conset-1 new-size)
268 (conset-grow conset-2 new-size))
269 (let ((vector1 (conset-vector conset-1))
270 (vector2 (conset-vector conset-2)))
271 (declare (simple-bit-vector vector1 vector2))
272 (setf (conset-vector conset-1) (,bit-op vector1 vector2 t))
273 ;; Update the extrema.
276 `(setf (conset-min conset-1)
277 (min (conset-min conset-1)
278 (conset-min conset-2))
279 (conset-max conset-1)
280 (max (conset-max conset-1)
281 (conset-max conset-2))))
282 ((conset-intersection)
283 `(let ((start (max (conset-min conset-1)
284 (conset-min conset-2)))
285 (end (min (conset-max conset-1)
286 (conset-max conset-2))))
287 (setf (conset-min conset-1)
290 (or (position 1 (conset-vector conset-1)
291 :start start :end end)
293 (conset-max conset-1)
298 1 (conset-vector conset-1)
299 :start start :end end :from-end t)))
304 `(setf (conset-min conset-1)
305 (or (position 1 (conset-vector conset-1)
306 :start (conset-min conset-1)
307 :end (conset-max conset-1))
309 (conset-max conset-1)
312 1 (conset-vector conset-1)
313 :start (conset-min conset-1)
314 :end (conset-max conset-1)
320 (defconsetop conset-union bit-ior)
321 (defconsetop conset-intersection bit-and)
322 (defconsetop conset-difference bit-andc2)))
324 ;;; Constraints are hash-consed. Unfortunately, types aren't, so we have
325 ;;; to over-approximate and then linear search through the potential hits.
326 ;;; LVARs can only be found in EQL (not-p = NIL) constraints, while constant
327 ;;; and lambda-vars can only be found in EQL constraints.
329 (defun find-constraint (kind x y not-p)
330 (declare (type lambda-var x) (type constraint-y y) (type boolean not-p))
333 (awhen (lambda-var-ctype-constraints x)
334 (dolist (con (gethash (sb!kernel::type-class-info y) it) nil)
335 (when (and (eq (constraint-kind con) kind)
336 (eq (constraint-not-p con) not-p)
337 (type= (constraint-y con) y))
338 (return-from find-constraint con)))
341 (awhen (lambda-var-eq-constraints x)
343 ((or constant lambda-var)
344 (awhen (lambda-var-eq-constraints x)
345 (let ((cache (gethash y it)))
346 (declare (type list cache))
347 (if not-p (cdr cache) (car cache)))))))
349 (defun register-constraint (x con y)
350 (declare (type lambda-var x) (type constraint con) (type constraint-y y))
351 (conset-adjoin con (lambda-var-constraints x))
352 (macrolet ((ensuref (place default)
353 `(or ,place (setf ,place ,default))))
356 (let ((index (ensuref (lambda-var-ctype-constraints x)
358 (push con (gethash (sb!kernel::type-class-info y) index))))
360 (let ((index (ensuref (lambda-var-eq-constraints x)
362 (setf (gethash y index) con)))
363 ((or constant lambda-var)
364 (let* ((index (ensuref (lambda-var-eq-constraints x)
366 (cons (ensuref (gethash y index) (list nil))))
367 (if (constraint-not-p con)
368 (setf (cdr cons) con)
369 (setf (car cons) con))))))
372 ;;; Return a constraint for the specified arguments. We only create a
373 ;;; new constraint if there isn't already an equivalent old one,
374 ;;; guaranteeing that all equivalent constraints are EQ. This
375 ;;; shouldn't be called on LAMBDA-VARs with no CONSTRAINTS set.
376 (defun find-or-create-constraint (kind x y not-p)
377 (declare (type lambda-var x) (type constraint-y y) (type boolean not-p))
378 (or (find-constraint kind x y not-p)
379 (let ((new (make-constraint (length *constraint-universe*)
381 (vector-push-extend new *constraint-universe*
382 (1+ (length *constraint-universe*)))
383 (register-constraint x new y)
384 (when (lambda-var-p y)
385 (register-constraint y new x))
388 ;;; If REF is to a LAMBDA-VAR with CONSTRAINTs (i.e. we can do flow
389 ;;; analysis on it), then return the LAMBDA-VAR, otherwise NIL.
390 #!-sb-fluid (declaim (inline ok-ref-lambda-var))
391 (defun ok-ref-lambda-var (ref)
392 (declare (type ref ref))
393 (let ((leaf (ref-leaf ref)))
394 (when (and (lambda-var-p leaf)
395 (lambda-var-constraints leaf))
398 ;;; See if LVAR's single USE is a REF to a LAMBDA-VAR and they are EQL
399 ;;; according to CONSTRAINTS. Return LAMBDA-VAR if so.
400 (defun ok-lvar-lambda-var (lvar constraints)
401 (declare (type lvar lvar))
402 (let ((use (lvar-uses lvar)))
404 (let ((lambda-var (ok-ref-lambda-var use)))
406 (let ((constraint (find-constraint 'eql lambda-var lvar nil)))
407 (when (and constraint (conset-member constraint constraints))
410 (ok-lvar-lambda-var (cast-value use) constraints)))))
412 (defmacro do-eql-vars ((symbol (var constraints) &optional result) &body body)
413 (once-only ((var var))
414 `(let ((,symbol ,var))
418 (do-conset-elements (con ,constraints ,result)
419 (let ((other (and (eq (constraint-kind con) 'eql)
420 (eq (constraint-not-p con) nil)
421 (cond ((eq ,var (constraint-x con))
423 ((eq ,var (constraint-y con))
429 (when (lambda-var-p ,symbol)
432 ;;;; Searching constraints
434 ;;; Add the indicated test constraint to BLOCK. We don't add the
435 ;;; constraint if the block has multiple predecessors, since it only
436 ;;; holds on this particular path.
437 (defun add-test-constraint (fun x y not-p constraints target)
438 (cond ((and (eq 'eql fun) (lambda-var-p y) (not not-p))
439 (add-eql-var-var-constraint x y constraints target))
441 (do-eql-vars (x (x constraints))
442 (let ((con (find-or-create-constraint fun x y not-p)))
443 (conset-adjoin con target)))))
446 ;;; Add complementary constraints to the consequent and alternative
447 ;;; blocks of IF. We do nothing if X is NIL.
448 (defun add-complement-constraints (fun x y not-p constraints
449 consequent-constraints
450 alternative-constraints)
452 (add-test-constraint fun x y not-p constraints
453 consequent-constraints)
454 (add-test-constraint fun x y (not not-p) constraints
455 alternative-constraints))
458 ;;; Add test constraints to the consequent and alternative blocks of
459 ;;; the test represented by USE.
460 (defun add-test-constraints (use if constraints)
461 (declare (type node use) (type cif if))
462 ;; Note: Even if we do (IF test exp exp) => (PROGN test exp)
463 ;; optimization, the *MAX-OPTIMIZE-ITERATIONS* cutoff means that we
464 ;; can't guarantee that the optimization will be done, so we still
465 ;; need to avoid barfing on this case.
466 (unless (eq (if-consequent if) (if-alternative if))
467 (let ((consequent-constraints (make-conset))
468 (alternative-constraints (make-conset)))
469 (macrolet ((add (fun x y not-p)
470 `(add-complement-constraints ,fun ,x ,y ,not-p
472 consequent-constraints
473 alternative-constraints)))
476 (add 'typep (ok-lvar-lambda-var (ref-lvar use) constraints)
477 (specifier-type 'null) t))
479 (unless (eq (combination-kind use)
481 (let ((name (lvar-fun-name
482 (basic-combination-fun use)))
483 (args (basic-combination-args use)))
485 ((%typep %instance-typep)
486 (let ((type (second args)))
487 (when (constant-lvar-p type)
488 (let ((val (lvar-value type)))
490 (ok-lvar-lambda-var (first args) constraints)
493 (let ((*compiler-error-context* use))
494 (specifier-type val)))
497 (let* ((arg1 (first args))
498 (var1 (ok-lvar-lambda-var arg1 constraints))
500 (var2 (ok-lvar-lambda-var arg2 constraints)))
501 ;; The code below assumes that the constant is the
502 ;; second argument in case of variable to constant
503 ;; comparision which is sometimes true (see source
504 ;; transformations for EQ, EQL and CHAR=). Fixing
505 ;; that would result in more constant substitutions
506 ;; which is not a universally good thing, thus the
507 ;; unnatural asymmetry of the tests.
510 (add-test-constraint 'typep var2 (lvar-type arg1)
512 consequent-constraints)))
514 (add 'eql var1 var2 nil))
515 ((constant-lvar-p arg2)
517 (let ((use (principal-lvar-use arg2)))
520 (find-constant (lvar-value arg2))))
523 (add-test-constraint 'typep var1 (lvar-type arg2)
525 consequent-constraints)))))
527 (let* ((arg1 (first args))
528 (var1 (ok-lvar-lambda-var arg1 constraints))
530 (var2 (ok-lvar-lambda-var arg2 constraints)))
532 (add name var1 (lvar-type arg2) nil))
534 (add (if (eq name '<) '> '<) var2 (lvar-type arg1) nil))))
536 (let ((ptype (gethash name *backend-predicate-types*)))
538 (add 'typep (ok-lvar-lambda-var (first args) constraints)
540 (values consequent-constraints alternative-constraints))))
542 ;;;; Applying constraints
544 ;;; Return true if X is an integer NUMERIC-TYPE.
545 (defun integer-type-p (x)
546 (declare (type ctype x))
547 (and (numeric-type-p x)
548 (eq (numeric-type-class x) 'integer)
549 (eq (numeric-type-complexp x) :real)))
551 ;;; Given that an inequality holds on values of type X and Y, return a
552 ;;; new type for X. If GREATER is true, then X was greater than Y,
553 ;;; otherwise less. If OR-EQUAL is true, then the inequality was
554 ;;; inclusive, i.e. >=.
556 ;;; If GREATER (or not), then we max (or min) in Y's lower (or upper)
557 ;;; bound into X and return that result. If not OR-EQUAL, we can go
558 ;;; one greater (less) than Y's bound.
559 (defun constrain-integer-type (x y greater or-equal)
560 (declare (type numeric-type x y))
567 (if greater (numeric-type-low x) (numeric-type-high x))))
568 (let* ((x-bound (bound x))
569 (y-bound (exclude (bound y)))
570 (new-bound (cond ((not x-bound) y-bound)
571 ((not y-bound) x-bound)
572 (greater (max x-bound y-bound))
573 (t (min x-bound y-bound)))))
575 (modified-numeric-type x :low new-bound)
576 (modified-numeric-type x :high new-bound)))))
578 ;;; Return true if X is a float NUMERIC-TYPE.
579 (defun float-type-p (x)
580 (declare (type ctype x))
581 (and (numeric-type-p x)
582 (eq (numeric-type-class x) 'float)
583 (eq (numeric-type-complexp x) :real)))
585 ;;; Exactly the same as CONSTRAIN-INTEGER-TYPE, but for float numbers.
586 (defun constrain-float-type (x y greater or-equal)
587 (declare (type numeric-type x y))
588 (declare (ignorable x y greater or-equal)) ; for CROSS-FLOAT-INFINITY-KLUDGE
590 (aver (eql (numeric-type-class x) 'float))
591 (aver (eql (numeric-type-class y) 'float))
592 #+sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.)
594 #-sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.)
595 (labels ((exclude (x)
603 (if greater (numeric-type-low x) (numeric-type-high x)))
608 (= (type-bound-number x) (type-bound-number ref)))
609 ;; X is tighter if REF is not an open bound and X is
610 (and (not (consp ref)) (consp x)))
612 (< (type-bound-number ref) (type-bound-number x)))
614 (> (type-bound-number ref) (type-bound-number x))))))
615 (let* ((x-bound (bound x))
616 (y-bound (exclude (bound y)))
617 (new-bound (cond ((not x-bound)
621 ((tighter-p y-bound x-bound)
626 (modified-numeric-type x :low new-bound)
627 (modified-numeric-type x :high new-bound)))))
629 ;;; Return true if LEAF is "visible" from NODE.
630 (defun leaf-visible-from-node-p (leaf node)
633 ;; A LAMBDA-VAR is visible iif it is homed in a CLAMBDA that is an
634 ;; ancestor for NODE.
635 (let ((leaf-lambda (lambda-var-home leaf)))
636 (loop for lambda = (node-home-lambda node)
637 then (lambda-parent lambda)
639 when (eq lambda leaf-lambda)
641 ;; FIXME: Check on FUNCTIONALs (CLAMBDAs and OPTIONAL-DISPATCHes),
642 ;; not just LAMBDA-VARs.
644 ;; Assume everything else is globally visible.
647 ;;; Given the set of CONSTRAINTS for a variable and the current set of
648 ;;; restrictions from flow analysis IN, set the type for REF
650 (defun constrain-ref-type (ref constraints in)
651 (declare (type ref ref) (type conset constraints in))
652 ;; KLUDGE: The NOT-SET and NOT-FPZ here are so that we don't need to
653 ;; cons up endless union types when propagating large number of EQL
654 ;; constraints -- eg. from large CASE forms -- instead we just
655 ;; directly accumulate one XSET, and a set of fp zeroes, which we at
656 ;; the end turn into a MEMBER-TYPE.
658 ;; Since massive symbol cases are an especially atrocious pattern
659 ;; and the (NOT (MEMBER ...ton of symbols...)) will never turn into
660 ;; a more useful type, don't propagate their negation except for NIL
661 ;; unless SPEED > COMPILATION-SPEED.
662 (let ((res (single-value-type (node-derived-type ref)))
663 (constrain-symbols (policy ref (> speed compilation-speed)))
664 (not-set (alloc-xset))
666 (not-res *empty-type*)
667 (leaf (ref-leaf ref)))
671 (when (or constrain-symbols (null x) (not (symbolp x)))
672 (add-to-xset x not-set)))))
673 ;; KLUDGE: the implementations of DO-CONSET-INTERSECTION will
674 ;; probably run faster when the smaller set comes first, so
675 ;; don't change the order here.
676 (do-conset-intersection (con constraints in)
677 (let* ((x (constraint-x con))
678 (y (constraint-y con))
679 (not-p (constraint-not-p con))
680 (other (if (eq x leaf) y x))
681 (kind (constraint-kind con)))
685 (if (member-type-p other)
686 (mapc-member-type-members #'note-not other)
687 (setq not-res (type-union not-res other)))
688 (setq res (type-approx-intersection2 res other))))
690 (unless (lvar-p other)
691 (let ((other-type (leaf-type other)))
693 (when (and (constant-p other)
694 (member-type-p other-type))
695 (note-not (constant-value other)))
696 (let ((leaf-type (leaf-type leaf)))
698 ((or (constant-p other)
699 (and (leaf-refs other) ; protect from
701 (csubtypep other-type leaf-type)
702 (not (type= other-type leaf-type))
703 ;; Don't change to a LEAF not visible here.
704 (leaf-visible-from-node-p other ref)))
705 (change-ref-leaf ref other)
706 (when (constant-p other) (return)))
708 (setq res (type-approx-intersection2
709 res other-type)))))))))
712 ((and (integer-type-p res) (integer-type-p y))
713 (let ((greater (eq kind '>)))
714 (let ((greater (if not-p (not greater) greater)))
716 (constrain-integer-type res y greater not-p)))))
717 ((and (float-type-p res) (float-type-p y))
718 (let ((greater (eq kind '>)))
719 (let ((greater (if not-p (not greater) greater)))
721 (constrain-float-type res y greater not-p)))))))))))
722 (cond ((and (if-p (node-dest ref))
723 (or (xset-member-p nil not-set)
724 (csubtypep (specifier-type 'null) not-res)))
725 (setf (node-derived-type ref) *wild-type*)
726 (change-ref-leaf ref (find-constant t)))
729 (type-union not-res (make-member-type :xset not-set :fp-zeroes not-fpz)))
730 (derive-node-type ref
731 (make-single-value-type
732 (or (type-difference res not-res)
734 (maybe-terminate-block ref nil))))
739 (defun maybe-add-eql-var-lvar-constraint (ref gen)
740 (let ((lvar (ref-lvar ref))
741 (leaf (ref-leaf ref)))
742 (when (and (lambda-var-p leaf) lvar)
743 (conset-adjoin (find-or-create-constraint 'eql leaf lvar nil)
746 ;;; Copy all CONSTRAINTS involving FROM-VAR - except the (EQL VAR
747 ;;; LVAR) ones - to all of the variables in the VARS list.
748 (defun inherit-constraints (vars from-var constraints target)
749 (do-conset-elements (con constraints)
750 ;; Constant substitution is controversial.
751 (unless (constant-p (constraint-y con))
753 (let ((eq-x (eq from-var (constraint-x con)))
754 (eq-y (eq from-var (constraint-y con))))
755 (when (or (and eq-x (not (lvar-p (constraint-y con))))
757 (conset-adjoin (find-or-create-constraint
758 (constraint-kind con)
759 (if eq-x var (constraint-x con))
760 (if eq-y var (constraint-y con))
761 (constraint-not-p con))
764 ;; Add an (EQL LAMBDA-VAR LAMBDA-VAR) constraint on VAR1 and VAR2 and
765 ;; inherit each other's constraints.
766 (defun add-eql-var-var-constraint (var1 var2 constraints
767 &optional (target constraints))
768 (let ((con (find-or-create-constraint 'eql var1 var2 nil)))
769 (when (conset-adjoin con target)
770 (collect ((eql1) (eql2))
771 (do-eql-vars (var1 (var1 constraints))
773 (do-eql-vars (var2 (var2 constraints))
775 (inherit-constraints (eql1) var2 constraints target)
776 (inherit-constraints (eql2) var1 constraints target))
779 ;; Add an (EQL LAMBDA-VAR LAMBDA-VAR) constraint on VAR and LVAR's
780 ;; LAMBDA-VAR if possible.
781 (defun maybe-add-eql-var-var-constraint (var lvar constraints
782 &optional (target constraints))
783 (declare (type lambda-var var) (type lvar lvar))
784 (let ((lambda-var (ok-lvar-lambda-var lvar constraints)))
786 (add-eql-var-var-constraint var lambda-var constraints target))))
788 ;;; Local propagation
789 ;;; -- [TODO: For any LAMBDA-VAR ref with a type check, add that
791 ;;; -- For any LAMBDA-VAR set, delete all constraints on that var; add
792 ;;; a type constraint based on the new value type.
793 (declaim (ftype (function (cblock conset boolean)
795 constraint-propagate-in-block))
796 (defun constraint-propagate-in-block (block gen preprocess-refs-p)
797 (do-nodes (node lvar block)
800 (let ((fun (bind-lambda node)))
801 (when (eq (functional-kind fun) :let)
802 (loop with call = (lvar-dest (node-lvar (first (lambda-refs fun))))
803 for var in (lambda-vars fun)
804 and val in (combination-args call)
805 when (and val (lambda-var-constraints var))
806 do (let ((type (lvar-type val)))
807 (unless (eq type *universal-type*)
808 (let ((con (find-or-create-constraint 'typep var type nil)))
809 (conset-adjoin con gen))))
810 (maybe-add-eql-var-var-constraint var val gen)))))
812 (when (ok-ref-lambda-var node)
813 (maybe-add-eql-var-lvar-constraint node gen)
814 (when preprocess-refs-p
815 (let* ((var (ref-leaf node))
816 (con (lambda-var-constraints var)))
817 (constrain-ref-type node con gen)))))
819 (let ((lvar (cast-value node)))
820 (let ((var (ok-lvar-lambda-var lvar gen)))
822 (let ((atype (single-value-type (cast-derived-type node)))) ;FIXME
823 (unless (eq atype *universal-type*)
824 (do-eql-vars (var (var gen))
825 (let ((con (find-or-create-constraint 'typep var atype nil)))
826 (conset-adjoin con gen)))))))))
828 (binding* ((var (set-var node))
829 (nil (lambda-var-p var) :exit-if-null)
830 (cons (lambda-var-constraints var) :exit-if-null))
831 (conset-difference gen cons)
832 (let ((type (single-value-type (node-derived-type node))))
833 (unless (eq type *universal-type*)
834 (let ((con (find-or-create-constraint 'typep var type nil)))
835 (conset-adjoin con gen))))
836 (maybe-add-eql-var-var-constraint var (set-value node) gen)))))
839 (defun constraint-propagate-if (block gen)
840 (let ((node (block-last block)))
842 (let ((use (lvar-uses (if-test node))))
844 (add-test-constraints use node gen))))))
846 ;;; Starting from IN compute OUT and (consequent/alternative
847 ;;; constraints if the block ends with and IF). Return the list of
848 ;;; successors that may need to be recomputed.
849 (defun find-block-type-constraints (block final-pass-p)
850 (declare (type cblock block))
851 (let ((gen (constraint-propagate-in-block
855 (copy-conset (block-in block)))
857 (setf (block-gen block) gen)
858 (multiple-value-bind (consequent-constraints alternative-constraints)
859 (constraint-propagate-if block gen)
860 (if consequent-constraints
861 (let* ((node (block-last block))
862 (old-consequent-constraints (if-consequent-constraints node))
863 (old-alternative-constraints (if-alternative-constraints node))
865 ;; Add the consequent and alternative constraints to GEN.
866 (cond ((conset-empty consequent-constraints)
867 (setf (if-consequent-constraints node) gen)
868 (setf (if-alternative-constraints node) gen))
870 (setf (if-consequent-constraints node) (copy-conset gen))
871 (conset-union (if-consequent-constraints node)
872 consequent-constraints)
873 (setf (if-alternative-constraints node) gen)
874 (conset-union (if-alternative-constraints node)
875 alternative-constraints)))
876 ;; Has the consequent been changed?
877 (unless (and old-consequent-constraints
878 (conset= (if-consequent-constraints node)
879 old-consequent-constraints))
880 (push (if-consequent node) succ))
881 ;; Has the alternative been changed?
882 (unless (and old-alternative-constraints
883 (conset= (if-alternative-constraints node)
884 old-alternative-constraints))
885 (push (if-alternative node) succ))
888 (unless (and (block-out block)
889 (conset= gen (block-out block)))
890 (setf (block-out block) gen)
891 (block-succ block))))))
893 ;;; Deliver the results of constraint propagation to REFs in BLOCK.
894 ;;; During this pass, we also do local constraint propagation by
895 ;;; adding in constraints as we see them during the pass through the
897 (defun use-result-constraints (block)
898 (declare (type cblock block))
899 (constraint-propagate-in-block block (block-in block) t))
901 ;;; Give an empty constraints set to any var that doesn't have one and
902 ;;; isn't a set closure var. Since a var that we previously rejected
903 ;;; looks identical to one that is new, so we optimistically keep
904 ;;; hoping that vars stop being closed over or lose their sets.
905 (defun init-var-constraints (component)
906 (declare (type component component))
907 (dolist (fun (component-lambdas component))
909 (dolist (var (lambda-vars x))
910 (unless (lambda-var-constraints var)
911 (when (or (null (lambda-var-sets var))
912 (not (closure-var-p var)))
913 (setf (lambda-var-constraints var) (make-conset)))))))
915 (dolist (let (lambda-lets fun))
918 ;;; Return the constraints that flow from PRED to SUCC. This is
919 ;;; BLOCK-OUT unless PRED ends with an IF and test constraints were
921 (defun block-out-for-successor (pred succ)
922 (declare (type cblock pred succ))
923 (let ((last (block-last pred)))
924 (or (when (if-p last)
925 (cond ((eq succ (if-consequent last))
926 (if-consequent-constraints last))
927 ((eq succ (if-alternative last))
928 (if-alternative-constraints last))))
931 (defun compute-block-in (block)
933 (dolist (pred (block-pred block))
934 ;; If OUT has not been calculated, assume it to be the universal
936 (let ((out (block-out-for-successor pred block)))
939 (conset-intersection in out)
940 (setq in (copy-conset out))))))
941 (or in (make-conset))))
943 (defun update-block-in (block)
944 (let ((in (compute-block-in block)))
945 (cond ((and (block-in block) (conset= in (block-in block)))
948 (setf (block-in block) in)))))
950 ;;; Return two lists: one of blocks that precede all loops and
951 ;;; therefore require only one constraint propagation pass and the
952 ;;; rest. This implementation does not find all such blocks.
954 ;;; A more complete implementation would be:
956 ;;; (do-blocks (block component)
957 ;;; (if (every #'(lambda (pred)
958 ;;; (or (member pred leading-blocks)
960 ;;; (block-pred block))
961 ;;; (push block leading-blocks)
962 ;;; (push block rest-of-blocks)))
964 ;;; Trailing blocks that succeed all loops could be found and handled
965 ;;; similarly. In practice though, these more complex solutions are
966 ;;; slightly worse performancewise.
967 (defun leading-component-blocks (component)
968 (declare (type component component))
969 (flet ((loopy-p (block)
970 (let ((n (block-number block)))
971 (dolist (pred (block-pred block))
972 (unless (< n (block-number pred))
974 (let ((leading-blocks ())
977 (do-blocks (block component)
978 (when (and (not seen-loop-p) (loopy-p block))
979 (setq seen-loop-p t))
981 (push block rest-of-blocks)
982 (push block leading-blocks)))
983 (values (nreverse leading-blocks) (nreverse rest-of-blocks)))))
985 ;;; Append OBJ to the end of LIST as if by NCONC but only if it is not
986 ;;; a member already.
987 (defun nconc-new (obj list)
988 (do ((x list (cdr x))
992 (setf (cdr prev) (list obj))
995 (when (eql (car x) obj)
996 (return-from nconc-new list))))
998 (defun find-and-propagate-constraints (component)
999 (let ((blocks-to-process ()))
1000 (flet ((enqueue (blocks)
1001 (dolist (block blocks)
1002 (setq blocks-to-process (nconc-new block blocks-to-process)))))
1003 (multiple-value-bind (leading-blocks rest-of-blocks)
1004 (leading-component-blocks component)
1005 ;; Update every block once to account for changes in the
1006 ;; IR1. The constraints of the lead blocks cannot be changed
1007 ;; after the first pass so we might as well use them and skip
1008 ;; USE-RESULT-CONSTRAINTS later.
1009 (dolist (block leading-blocks)
1010 (setf (block-in block) (compute-block-in block))
1011 (find-block-type-constraints block t))
1012 (setq blocks-to-process (copy-list rest-of-blocks))
1013 ;; The rest of the blocks.
1014 (dolist (block rest-of-blocks)
1015 (aver (eq block (pop blocks-to-process)))
1016 (setf (block-in block) (compute-block-in block))
1017 (enqueue (find-block-type-constraints block nil)))
1018 ;; Propagate constraints
1019 (loop for block = (pop blocks-to-process)
1021 (unless (eq block (component-tail component))
1022 (when (update-block-in block)
1023 (enqueue (find-block-type-constraints block nil)))))
1026 (defun constraint-propagate (component)
1027 (declare (type component component))
1028 (init-var-constraints component)
1030 (unless (block-out (component-head component))
1031 (setf (block-out (component-head component)) (make-conset)))
1033 (dolist (block (find-and-propagate-constraints component))
1034 (unless (block-delete-p block)
1035 (use-result-constraints block)))