1 ;;;; This file implements the IR1 optimization phase of the compiler.
2 ;;;; IR1 optimization is a grab-bag of optimizations that don't make
3 ;;;; major changes to the block-level control flow and don't use flow
4 ;;;; analysis. These optimizations can mostly be classified as
5 ;;;; "meta-evaluation", but there is a sizable top-down component as
8 ;;;; This software is part of the SBCL system. See the README file for
11 ;;;; This software is derived from the CMU CL system, which was
12 ;;;; written at Carnegie Mellon University and released into the
13 ;;;; public domain. The software is in the public domain and is
14 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
15 ;;;; files for more information.
19 ;;;; interface for obtaining results of constant folding
21 ;;; Return true for a CONTINUATION whose sole use is a reference to a
23 (defun constant-continuation-p (thing)
24 (and (continuation-p thing)
25 (let ((use (continuation-use thing)))
27 (constant-p (ref-leaf use))))))
29 ;;; Return the constant value for a continuation whose only use is a
31 (declaim (ftype (function (continuation) t) continuation-value))
32 (defun continuation-value (cont)
33 (aver (constant-continuation-p cont))
34 (constant-value (ref-leaf (continuation-use cont))))
36 ;;;; interface for obtaining results of type inference
38 ;;; Return a (possibly values) type that describes what we have proven
39 ;;; about the type of Cont without taking any type assertions into
40 ;;; consideration. This is just the union of the NODE-DERIVED-TYPE of
41 ;;; all the uses. Most often people use CONTINUATION-DERIVED-TYPE or
42 ;;; CONTINUATION-TYPE instead of using this function directly.
43 (defun continuation-proven-type (cont)
44 (declare (type continuation cont))
45 (ecase (continuation-kind cont)
46 ((:block-start :deleted-block-start)
47 (let ((uses (block-start-uses (continuation-block cont))))
49 (do ((res (node-derived-type (first uses))
50 (values-type-union (node-derived-type (first current))
52 (current (rest uses) (rest current)))
56 (node-derived-type (continuation-use cont)))))
58 ;;; Our best guess for the type of this continuation's value. Note
59 ;;; that this may be VALUES or FUNCTION type, which cannot be passed
60 ;;; as an argument to the normal type operations. See
61 ;;; CONTINUATION-TYPE. This may be called on deleted continuations,
62 ;;; always returning *.
64 ;;; What we do is call CONTINUATION-PROVEN-TYPE and check whether the
65 ;;; result is a subtype of the assertion. If so, return the proven
66 ;;; type and set TYPE-CHECK to nil. Otherwise, return the intersection
67 ;;; of the asserted and proven types, and set TYPE-CHECK T. If
68 ;;; TYPE-CHECK already has a non-null value, then preserve it. Only in
69 ;;; the somewhat unusual circumstance of a newly discovered assertion
70 ;;; will we change TYPE-CHECK from NIL to T.
72 ;;; The result value is cached in the CONTINUATION-%DERIVED-TYPE slot.
73 ;;; If the slot is true, just return that value, otherwise recompute
74 ;;; and stash the value there.
75 #!-sb-fluid (declaim (inline continuation-derived-type))
76 (defun continuation-derived-type (cont)
77 (declare (type continuation cont))
78 (or (continuation-%derived-type cont)
79 (%continuation-derived-type cont)))
80 (defun %continuation-derived-type (cont)
81 (declare (type continuation cont))
82 (let ((proven (continuation-proven-type cont))
83 (asserted (continuation-asserted-type cont)))
84 (cond ((values-subtypep proven asserted)
85 (setf (continuation-%type-check cont) nil)
86 (setf (continuation-%derived-type cont) proven))
87 ((and (values-subtypep proven (specifier-type 'function))
88 (values-subtypep asserted (specifier-type 'function)))
89 ;; It's physically impossible for a runtime type check to
90 ;; distinguish between the various subtypes of FUNCTION, so
91 ;; it'd be pointless to do more type checks here.
92 (setf (continuation-%type-check cont) nil)
93 (setf (continuation-%derived-type cont)
94 ;; FIXME: This should depend on optimization
95 ;; policy. This is for SPEED > SAFETY:
96 #+nil (values-type-intersection asserted proven)
97 ;; and this is for SAFETY >= SPEED:
100 (unless (or (continuation-%type-check cont)
101 (not (continuation-dest cont))
102 (eq asserted *universal-type*))
103 (setf (continuation-%type-check cont) t))
105 (setf (continuation-%derived-type cont)
106 (values-type-intersection asserted proven))))))
108 ;;; Call CONTINUATION-DERIVED-TYPE to make sure the slot is up to
109 ;;; date, then return it.
110 #!-sb-fluid (declaim (inline continuation-type-check))
111 (defun continuation-type-check (cont)
112 (declare (type continuation cont))
113 (continuation-derived-type cont)
114 (continuation-%type-check cont))
116 ;;; Return the derived type for CONT's first value. This is guaranteed
117 ;;; not to be a VALUES or FUNCTION type.
118 (declaim (ftype (function (continuation) ctype) continuation-type))
119 (defun continuation-type (cont)
120 (single-value-type (continuation-derived-type cont)))
122 ;;; If CONT is an argument of a function, return a type which the
123 ;;; function checks CONT for.
124 #!-sb-fluid (declaim (inline continuation-externally-checkable-type))
125 (defun continuation-externally-checkable-type (cont)
126 (or (continuation-%externally-checkable-type cont)
127 (%continuation-%externally-checkable-type cont)))
128 (defun %continuation-%externally-checkable-type (cont)
129 (declare (type continuation cont))
130 (let ((dest (continuation-dest cont)))
131 (if (not (and dest (combination-p dest)))
132 ;; TODO: MV-COMBINATION
133 (setf (continuation-%externally-checkable-type cont) *wild-type*)
134 (let* ((fun (combination-fun dest))
135 (args (combination-args dest))
136 (fun-type (continuation-type fun)))
137 (if (or (not (fun-type-p fun-type))
138 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
139 (fun-type-wild-args fun-type))
140 (progn (dolist (arg args)
142 (setf (continuation-%externally-checkable-type arg)
145 (let* ((arg-types (append (fun-type-required fun-type)
146 (fun-type-optional fun-type)
147 (let ((rest (list (or (fun-type-rest fun-type)
149 (setf (cdr rest) rest)))))
152 for arg of-type continuation in args
153 and type of-type ctype in arg-types
155 (setf (continuation-%externally-checkable-type arg)
157 (continuation-%externally-checkable-type cont)))))))
159 ;;;; interface routines used by optimizers
161 ;;; This function is called by optimizers to indicate that something
162 ;;; interesting has happened to the value of Cont. Optimizers must
163 ;;; make sure that they don't call for reoptimization when nothing has
164 ;;; happened, since optimization will fail to terminate.
166 ;;; We clear any cached type for the continuation and set the
167 ;;; reoptimize flags on everything in sight, unless the continuation
168 ;;; is deleted (in which case we do nothing.)
170 ;;; Since this can get called during IR1 conversion, we have to be
171 ;;; careful not to fly into space when the Dest's Prev is missing.
172 (defun reoptimize-continuation (cont)
173 (declare (type continuation cont))
174 (unless (member (continuation-kind cont) '(:deleted :unused))
175 (setf (continuation-%derived-type cont) nil)
176 (let ((dest (continuation-dest cont)))
178 (setf (continuation-reoptimize cont) t)
179 (setf (node-reoptimize dest) t)
180 (let ((prev (node-prev dest)))
182 (let* ((block (continuation-block prev))
183 (component (block-component block)))
184 (when (typep dest 'cif)
185 (setf (block-test-modified block) t))
186 (setf (block-reoptimize block) t)
187 (setf (component-reoptimize component) t))))))
189 (setf (block-type-check (node-block node)) t)))
192 ;;; Annotate NODE to indicate that its result has been proven to be
193 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
194 ;;; only correct way to supply information discovered about a node's
195 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
196 ;;; information may be lost and reoptimization may not happen.
198 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
199 ;;; intersection is different from the old type, then we do a
200 ;;; REOPTIMIZE-CONTINUATION on the NODE-CONT.
201 (defun derive-node-type (node rtype)
202 (declare (type node node) (type ctype rtype))
203 (let ((node-type (node-derived-type node)))
204 (unless (eq node-type rtype)
205 (let ((int (values-type-intersection node-type rtype)))
206 (when (type/= node-type int)
207 (when (and *check-consistency*
208 (eq int *empty-type*)
209 (not (eq rtype *empty-type*)))
210 (let ((*compiler-error-context* node))
212 "New inferred type ~S conflicts with old type:~
213 ~% ~S~%*** possible internal error? Please report this."
214 (type-specifier rtype) (type-specifier node-type))))
215 (setf (node-derived-type node) int)
216 (reoptimize-continuation (node-cont node))))))
219 (defun set-continuation-type-assertion (cont atype ctype)
220 (declare (type continuation cont) (type ctype atype ctype))
221 (when (eq atype *wild-type*)
222 (return-from set-continuation-type-assertion))
223 (let* ((old-atype (continuation-asserted-type cont))
224 (old-ctype (continuation-type-to-check cont))
225 (new-atype (values-type-intersection old-atype atype))
226 (new-ctype (values-type-intersection old-ctype ctype)))
227 (when (or (type/= old-atype new-atype)
228 (type/= old-ctype new-ctype))
229 (setf (continuation-asserted-type cont) new-atype)
230 (setf (continuation-type-to-check cont) new-ctype)
232 (setf (block-attributep (block-flags (node-block node))
233 type-check type-asserted)
235 (reoptimize-continuation cont)))
238 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
239 ;;; error for CONT's value not to be TYPEP to TYPE. If we improve the
240 ;;; assertion, we set TYPE-CHECK and TYPE-ASSERTED to guarantee that
241 ;;; the new assertion will be checked.
242 (defun assert-continuation-type (cont type policy)
243 (declare (type continuation cont) (type ctype type))
244 (when (eq type *wild-type*)
245 (return-from assert-continuation-type))
246 (set-continuation-type-assertion cont type (maybe-weaken-check type policy)))
248 ;;; Assert that CALL is to a function of the specified TYPE. It is
249 ;;; assumed that the call is legal and has only constants in the
250 ;;; keyword positions.
251 (defun assert-call-type (call type)
252 (declare (type combination call) (type fun-type type))
253 (derive-node-type call (fun-type-returns type))
254 (let ((args (combination-args call))
255 (policy (lexenv-policy (node-lexenv call))))
256 (dolist (req (fun-type-required type))
257 (when (null args) (return-from assert-call-type))
258 (let ((arg (pop args)))
259 (assert-continuation-type arg req policy)))
260 (dolist (opt (fun-type-optional type))
261 (when (null args) (return-from assert-call-type))
262 (let ((arg (pop args)))
263 (assert-continuation-type arg opt policy)))
265 (let ((rest (fun-type-rest type)))
268 (assert-continuation-type arg rest policy))))
270 (dolist (key (fun-type-keywords type))
271 (let ((name (key-info-name key)))
272 (do ((arg args (cddr arg)))
274 (when (eq (continuation-value (first arg)) name)
275 (assert-continuation-type
276 (second arg) (key-info-type key)
282 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
283 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
284 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
285 ;;; we are done, then another iteration would be beneficial.
286 (defun ir1-optimize (component)
287 (declare (type component component))
288 (setf (component-reoptimize component) nil)
289 (do-blocks (block component)
291 ;; We delete blocks when there is either no predecessor or the
292 ;; block is in a lambda that has been deleted. These blocks
293 ;; would eventually be deleted by DFO recomputation, but doing
294 ;; it here immediately makes the effect available to IR1
296 ((or (block-delete-p block)
297 (null (block-pred block)))
298 (delete-block block))
299 ((eq (functional-kind (block-home-lambda block)) :deleted)
300 ;; Preserve the BLOCK-SUCC invariant that almost every block has
301 ;; one successor (and a block with DELETE-P set is an acceptable
303 (mark-for-deletion block)
304 (delete-block block))
307 (let ((succ (block-succ block)))
308 (unless (and succ (null (rest succ)))
311 (let ((last (block-last block)))
314 (flush-dest (if-test last))
315 (when (unlink-node last)
318 (when (maybe-delete-exit last)
321 (unless (join-successor-if-possible block)
324 (when (and (block-reoptimize block) (block-component block))
325 (aver (not (block-delete-p block)))
326 (ir1-optimize-block block))
328 (cond ((block-delete-p block)
329 (delete-block block))
330 ((and (block-flush-p block) (block-component block))
331 (flush-dead-code block))))))
335 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
338 ;;; Note that although they are cleared here, REOPTIMIZE flags might
339 ;;; still be set upon return from this function, meaning that further
340 ;;; optimization is wanted (as a consequence of optimizations we did).
341 (defun ir1-optimize-block (block)
342 (declare (type cblock block))
343 ;; We clear the node and block REOPTIMIZE flags before doing the
344 ;; optimization, not after. This ensures that the node or block will
345 ;; be reoptimized if necessary.
346 (setf (block-reoptimize block) nil)
347 (do-nodes (node cont block :restart-p t)
348 (when (node-reoptimize node)
349 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
350 (setf (node-reoptimize node) nil)
354 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
355 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
356 ;; any argument changes.
357 (ir1-optimize-combination node))
359 (ir1-optimize-if node))
361 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
362 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
363 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
365 (setf (node-reoptimize node) t)
366 (ir1-optimize-return node))
368 (ir1-optimize-mv-combination node))
370 ;; With an EXIT, we derive the node's type from the VALUE's
371 ;; type. We don't propagate CONT's assertion to the VALUE,
372 ;; since if we did, this would move the checking of CONT's
373 ;; assertion to the exit. This wouldn't work with CATCH and
374 ;; UWP, where the EXIT node is just a placeholder for the
375 ;; actual unknown exit.
376 (let ((value (exit-value node)))
378 (derive-node-type node (continuation-derived-type value)))))
380 (ir1-optimize-set node)))))
383 ;;; Try to join with a successor block. If we succeed, we return true,
385 (defun join-successor-if-possible (block)
386 (declare (type cblock block))
387 (let ((next (first (block-succ block))))
388 (when (block-start next)
389 (let* ((last (block-last block))
390 (last-cont (node-cont last))
391 (next-cont (block-start next)))
392 (cond (;; We cannot combine with a successor block if:
394 ;; The successor has more than one predecessor.
395 (rest (block-pred next))
396 ;; The last node's CONT is also used somewhere else.
397 (not (eq (continuation-use last-cont) last))
398 ;; The successor is the current block (infinite loop).
400 ;; The next block has a different cleanup, and thus
401 ;; we may want to insert cleanup code between the
402 ;; two blocks at some point.
403 (not (eq (block-end-cleanup block)
404 (block-start-cleanup next)))
405 ;; The next block has a different home lambda, and
406 ;; thus the control transfer is a non-local exit.
407 (not (eq (block-home-lambda block)
408 (block-home-lambda next))))
410 ;; Joining is easy when the successor's START
411 ;; continuation is the same from our LAST's CONT.
412 ((eq last-cont next-cont)
413 (join-blocks block next)
415 ;; If they differ, then we can still join when the last
416 ;; continuation has no next and the next continuation
418 ((and (null (block-start-uses next))
419 (eq (continuation-kind last-cont) :inside-block))
420 ;; In this case, we replace the next
421 ;; continuation with the last before joining the blocks.
422 (let ((next-node (continuation-next next-cont)))
423 ;; If NEXT-CONT does have a dest, it must be
424 ;; unreachable, since there are no USES.
425 ;; DELETE-CONTINUATION will mark the dest block as
426 ;; DELETE-P [and also this block, unless it is no
427 ;; longer backward reachable from the dest block.]
428 (delete-continuation next-cont)
429 (setf (node-prev next-node) last-cont)
430 (setf (continuation-next last-cont) next-node)
431 (setf (block-start next) last-cont)
432 (join-blocks block next))
437 ;;; Join together two blocks which have the same ending/starting
438 ;;; continuation. The code in BLOCK2 is moved into BLOCK1 and BLOCK2
439 ;;; is deleted from the DFO. We combine the optimize flags for the two
440 ;;; blocks so that any indicated optimization gets done.
441 (defun join-blocks (block1 block2)
442 (declare (type cblock block1 block2))
443 (let* ((last (block-last block2))
444 (last-cont (node-cont last))
445 (succ (block-succ block2))
446 (start2 (block-start block2)))
447 (do ((cont start2 (node-cont (continuation-next cont))))
449 (when (eq (continuation-kind last-cont) :inside-block)
450 (setf (continuation-block last-cont) block1)))
451 (setf (continuation-block cont) block1))
453 (unlink-blocks block1 block2)
455 (unlink-blocks block2 block)
456 (link-blocks block1 block))
458 (setf (block-last block1) last)
459 (setf (continuation-kind start2) :inside-block))
461 (setf (block-flags block1)
462 (attributes-union (block-flags block1)
464 (block-attributes type-asserted test-modified)))
466 (let ((next (block-next block2))
467 (prev (block-prev block2)))
468 (setf (block-next prev) next)
469 (setf (block-prev next) prev))
473 ;;; Delete any nodes in BLOCK whose value is unused and which have no
474 ;;; side effects. We can delete sets of lexical variables when the set
475 ;;; variable has no references.
476 (defun flush-dead-code (block)
477 (declare (type cblock block))
478 (do-nodes-backwards (node cont block)
479 (unless (continuation-dest cont)
485 (let ((info (combination-kind node)))
486 (when (fun-info-p info)
487 (let ((attr (fun-info-attributes info)))
488 (when (and (not (ir1-attributep attr call))
489 ;; ### For now, don't delete potentially
490 ;; flushable calls when they have the CALL
491 ;; attribute. Someday we should look at the
492 ;; functional args to determine if they have
494 (if (policy node (= safety 3))
495 (and (ir1-attributep attr flushable)
497 ;; FIXME: when bug 203
498 ;; will be fixed, remove
500 (member (continuation-type-check arg)
502 (basic-combination-args node))
504 (info :function :type
505 (leaf-source-name (ref-leaf (continuation-use (basic-combination-fun node)))))
506 :result-test #'always-subtypep
509 (ir1-attributep attr unsafely-flushable)))
510 (flush-dest (combination-fun node))
511 (dolist (arg (combination-args node))
513 (unlink-node node))))))
515 (when (eq (basic-combination-kind node) :local)
516 (let ((fun (combination-lambda node)))
517 (when (dolist (var (lambda-vars fun) t)
518 (when (or (leaf-refs var)
519 (lambda-var-sets var))
521 (flush-dest (first (basic-combination-args node)))
524 (let ((value (exit-value node)))
527 (setf (exit-value node) nil))))
529 (let ((var (set-var node)))
530 (when (and (lambda-var-p var)
531 (null (leaf-refs var)))
532 (flush-dest (set-value node))
533 (setf (basic-var-sets var)
534 (delete node (basic-var-sets var)))
535 (unlink-node node)))))))
537 (setf (block-flush-p block) nil)
540 ;;;; local call return type propagation
542 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
543 ;;; flag set. It iterates over the uses of the RESULT, looking for
544 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
545 ;;; call, then we union its type together with the types of other such
546 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
547 ;;; type with the RESULT's asserted type. We can make this
548 ;;; intersection now (potentially before type checking) because this
549 ;;; assertion on the result will eventually be checked (if
552 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
553 ;;; combination, which may change the succesor of the call to be the
554 ;;; called function, and if so, checks if the call can become an
555 ;;; assignment. If we convert to an assignment, we abort, since the
556 ;;; RETURN has been deleted.
557 (defun find-result-type (node)
558 (declare (type creturn node))
559 (let ((result (return-result node)))
560 (collect ((use-union *empty-type* values-type-union))
561 (do-uses (use result)
562 (cond ((and (basic-combination-p use)
563 (eq (basic-combination-kind use) :local))
564 (aver (eq (lambda-tail-set (node-home-lambda use))
565 (lambda-tail-set (combination-lambda use))))
566 (when (combination-p use)
567 (when (nth-value 1 (maybe-convert-tail-local-call use))
568 (return-from find-result-type (values)))))
570 (use-union (node-derived-type use)))))
571 (let ((int (values-type-intersection
572 (continuation-asserted-type result)
574 (setf (return-result-type node) int))))
577 ;;; Do stuff to realize that something has changed about the value
578 ;;; delivered to a return node. Since we consider the return values of
579 ;;; all functions in the tail set to be equivalent, this amounts to
580 ;;; bringing the entire tail set up to date. We iterate over the
581 ;;; returns for all the functions in the tail set, reanalyzing them
582 ;;; all (not treating Node specially.)
584 ;;; When we are done, we check whether the new type is different from
585 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
586 ;;; all the continuations for references to functions in the tail set.
587 ;;; This will cause IR1-OPTIMIZE-COMBINATION to derive the new type as
588 ;;; the results of the calls.
589 (defun ir1-optimize-return (node)
590 (declare (type creturn node))
591 (let* ((tails (lambda-tail-set (return-lambda node)))
592 (funs (tail-set-funs tails)))
593 (collect ((res *empty-type* values-type-union))
595 (let ((return (lambda-return fun)))
597 (when (node-reoptimize return)
598 (setf (node-reoptimize return) nil)
599 (find-result-type return))
600 (res (return-result-type return)))))
602 (when (type/= (res) (tail-set-type tails))
603 (setf (tail-set-type tails) (res))
604 (dolist (fun (tail-set-funs tails))
605 (dolist (ref (leaf-refs fun))
606 (reoptimize-continuation (node-cont ref)))))))
612 ;;; If the test has multiple uses, replicate the node when possible.
613 ;;; Also check whether the predicate is known to be true or false,
614 ;;; deleting the IF node in favor of the appropriate branch when this
616 (defun ir1-optimize-if (node)
617 (declare (type cif node))
618 (let ((test (if-test node))
619 (block (node-block node)))
621 (when (and (eq (block-start block) test)
622 (eq (continuation-next test) node)
623 (rest (block-start-uses block)))
625 (when (immediately-used-p test use)
626 (convert-if-if use node)
627 (when (continuation-use test) (return)))))
629 (let* ((type (continuation-type test))
631 (cond ((constant-continuation-p test)
632 (if (continuation-value test)
633 (if-alternative node)
634 (if-consequent node)))
635 ((not (types-equal-or-intersect type (specifier-type 'null)))
636 (if-alternative node))
637 ((type= type (specifier-type 'null))
638 (if-consequent node)))))
641 (when (rest (block-succ block))
642 (unlink-blocks block victim))
643 (setf (component-reanalyze (node-component node)) t)
644 (unlink-node node))))
647 ;;; Create a new copy of an IF node that tests the value of the node
648 ;;; USE. The test must have >1 use, and must be immediately used by
649 ;;; USE. NODE must be the only node in its block (implying that
650 ;;; block-start = if-test).
652 ;;; This optimization has an effect semantically similar to the
653 ;;; source-to-source transformation:
654 ;;; (IF (IF A B C) D E) ==>
655 ;;; (IF A (IF B D E) (IF C D E))
657 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
658 ;;; node so that dead code deletion notes will definitely not consider
659 ;;; either node to be part of the original source. One node might
660 ;;; become unreachable, resulting in a spurious note.
661 (defun convert-if-if (use node)
662 (declare (type node use) (type cif node))
663 (with-ir1-environment-from-node node
664 (let* ((block (node-block node))
665 (test (if-test node))
666 (cblock (if-consequent node))
667 (ablock (if-alternative node))
668 (use-block (node-block use))
669 (dummy-cont (make-continuation))
670 (new-cont (make-continuation))
671 (new-node (make-if :test new-cont
673 :alternative ablock))
674 (new-block (continuation-starts-block new-cont)))
675 (link-node-to-previous-continuation new-node new-cont)
676 (setf (continuation-dest new-cont) new-node)
677 (setf (continuation-%externally-checkable-type new-cont) nil)
678 (add-continuation-use new-node dummy-cont)
679 (setf (block-last new-block) new-node)
681 (unlink-blocks use-block block)
682 (delete-continuation-use use)
683 (add-continuation-use use new-cont)
684 (link-blocks use-block new-block)
686 (link-blocks new-block cblock)
687 (link-blocks new-block ablock)
689 (push "<IF Duplication>" (node-source-path node))
690 (push "<IF Duplication>" (node-source-path new-node))
692 (reoptimize-continuation test)
693 (reoptimize-continuation new-cont)
694 (setf (component-reanalyze *current-component*) t)))
697 ;;;; exit IR1 optimization
699 ;;; This function attempts to delete an exit node, returning true if
700 ;;; it deletes the block as a consequence:
701 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
702 ;;; anything, since there is nothing to be done.
703 ;;; -- If the exit node and its ENTRY have the same home lambda then
704 ;;; we know the exit is local, and can delete the exit. We change
705 ;;; uses of the Exit-Value to be uses of the original continuation,
706 ;;; then unlink the node. If the exit is to a TR context, then we
707 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
708 ;;; their value to this exit.
709 ;;; -- If there is no value (as in a GO), then we skip the value
712 ;;; This function is also called by environment analysis, since it
713 ;;; wants all exits to be optimized even if normal optimization was
715 (defun maybe-delete-exit (node)
716 (declare (type exit node))
717 (let ((value (exit-value node))
718 (entry (exit-entry node))
719 (cont (node-cont node)))
721 (eq (node-home-lambda node) (node-home-lambda entry)))
722 (setf (entry-exits entry) (delete node (entry-exits entry)))
727 (when (return-p (continuation-dest cont))
729 (when (and (basic-combination-p use)
730 (eq (basic-combination-kind use) :local))
732 (substitute-continuation-uses cont value)
733 (dolist (merge (merges))
734 (merge-tail-sets merge))))))))
736 ;;;; combination IR1 optimization
738 ;;; Report as we try each transform?
740 (defvar *show-transforms-p* nil)
742 ;;; Do IR1 optimizations on a COMBINATION node.
743 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
744 (defun ir1-optimize-combination (node)
745 (when (continuation-reoptimize (basic-combination-fun node))
746 (propagate-fun-change node))
747 (let ((args (basic-combination-args node))
748 (kind (basic-combination-kind node)))
751 (let ((fun (combination-lambda node)))
752 (if (eq (functional-kind fun) :let)
753 (propagate-let-args node fun)
754 (propagate-local-call-args node fun))))
758 (setf (continuation-reoptimize arg) nil))))
762 (setf (continuation-reoptimize arg) nil)))
764 (let ((attr (fun-info-attributes kind)))
765 (when (and (ir1-attributep attr foldable)
766 ;; KLUDGE: The next test could be made more sensitive,
767 ;; only suppressing constant-folding of functions with
768 ;; CALL attributes when they're actually passed
769 ;; function arguments. -- WHN 19990918
770 (not (ir1-attributep attr call))
771 (every #'constant-continuation-p args)
772 (continuation-dest (node-cont node))
773 ;; Even if the function is foldable in principle,
774 ;; it might be one of our low-level
775 ;; implementation-specific functions. Such
776 ;; functions don't necessarily exist at runtime on
777 ;; a plain vanilla ANSI Common Lisp
778 ;; cross-compilation host, in which case the
779 ;; cross-compiler can't fold it because the
780 ;; cross-compiler doesn't know how to evaluate it.
782 (fboundp (combination-fun-source-name node)))
783 (constant-fold-call node)
784 (return-from ir1-optimize-combination)))
786 (let ((fun (fun-info-derive-type kind)))
788 (let ((res (funcall fun node)))
790 (derive-node-type node res)
791 (maybe-terminate-block node nil)))))
793 (let ((fun (fun-info-optimizer kind)))
794 (unless (and fun (funcall fun node))
795 (dolist (x (fun-info-transforms kind))
797 (when *show-transforms-p*
798 (let* ((cont (basic-combination-fun node))
799 (fname (continuation-fun-name cont t)))
800 (/show "trying transform" x (transform-function x) "for" fname)))
801 (unless (ir1-transform node x)
803 (when *show-transforms-p*
804 (/show "quitting because IR1-TRANSFORM result was NIL"))
809 ;;; If CALL is to a function that doesn't return (i.e. return type is
810 ;;; NIL), then terminate the block there, and link it to the component
811 ;;; tail. We also change the call's CONT to be a dummy continuation to
812 ;;; prevent the use from confusing things.
814 ;;; Except when called during IR1 [FIXME: What does this mean? Except
815 ;;; during IR1 conversion? What about IR1 optimization?], we delete
816 ;;; the continuation if it has no other uses. (If it does have other
817 ;;; uses, we reoptimize.)
819 ;;; Termination on the basis of a continuation type assertion is
821 ;;; -- The continuation is deleted (hence the assertion is spurious), or
822 ;;; -- We are in IR1 conversion (where THE assertions are subject to
824 (defun maybe-terminate-block (call ir1-converting-not-optimizing-p)
825 (declare (type basic-combination call))
826 (let* ((block (node-block call))
827 (cont (node-cont call))
828 (tail (component-tail (block-component block)))
829 (succ (first (block-succ block))))
830 (unless (or (and (eq call (block-last block)) (eq succ tail))
831 (block-delete-p block))
832 (when (or (and (eq (continuation-asserted-type cont) *empty-type*)
833 (not (or ir1-converting-not-optimizing-p
834 (eq (continuation-kind cont) :deleted))))
835 (eq (node-derived-type call) *empty-type*))
836 (cond (ir1-converting-not-optimizing-p
837 (delete-continuation-use call)
840 (aver (and (eq (block-last block) call)
841 (eq (continuation-kind cont) :block-start))))
843 (setf (block-last block) call)
844 (link-blocks block (continuation-starts-block cont)))))
846 (node-ends-block call)
847 (delete-continuation-use call)
848 (if (eq (continuation-kind cont) :unused)
849 (delete-continuation cont)
850 (reoptimize-continuation cont))))
852 (unlink-blocks block (first (block-succ block)))
853 (setf (component-reanalyze (block-component block)) t)
854 (aver (not (block-succ block)))
855 (link-blocks block tail)
856 (add-continuation-use call (make-continuation))
859 ;;; This is called both by IR1 conversion and IR1 optimization when
860 ;;; they have verified the type signature for the call, and are
861 ;;; wondering if something should be done to special-case the call. If
862 ;;; CALL is a call to a global function, then see whether it defined
864 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
865 ;;; the expansion and change the call to call it. Expansion is
866 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
867 ;;; true, we never expand, since this function has already been
868 ;;; converted. Local call analysis will duplicate the definition
869 ;;; if necessary. We claim that the parent form is LABELS for
870 ;;; context declarations, since we don't want it to be considered
871 ;;; a real global function.
872 ;;; -- If it is a known function, mark it as such by setting the KIND.
874 ;;; We return the leaf referenced (NIL if not a leaf) and the
875 ;;; FUN-INFO assigned.
877 ;;; FIXME: The IR1-CONVERTING-NOT-OPTIMIZING-P argument is what the
878 ;;; old CMU CL code called IR1-P, without explanation. My (WHN
879 ;;; 2002-01-09) tentative understanding of it is that we can call this
880 ;;; operation either in initial IR1 conversion or in later IR1
881 ;;; optimization, and it tells which is which. But it would be good
882 ;;; for someone who really understands it to check whether this is
884 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
885 (declare (type combination call))
886 (let* ((ref (continuation-use (basic-combination-fun call)))
887 (leaf (when (ref-p ref) (ref-leaf ref)))
888 (inlinep (if (defined-fun-p leaf)
889 (defined-fun-inlinep leaf)
892 ((eq inlinep :notinline) (values nil nil))
893 ((not (and (global-var-p leaf)
894 (eq (global-var-kind leaf) :global-function)))
899 ((nil :maybe-inline) (policy call (zerop space))))
901 (defined-fun-inline-expansion leaf)
902 (let ((fun (defined-fun-functional leaf)))
904 (and (eq inlinep :inline) (functional-kind fun))))
905 (inline-expansion-ok call))
906 (flet (;; FIXME: Is this what the old CMU CL internal documentation
907 ;; called semi-inlining? A more descriptive name would
908 ;; be nice. -- WHN 2002-01-07
910 (let ((res (ir1-convert-lambda-for-defun
911 (defined-fun-inline-expansion leaf)
913 #'ir1-convert-inline-lambda)))
914 (setf (defined-fun-functional leaf) res)
915 (change-ref-leaf ref res))))
916 (if ir1-converting-not-optimizing-p
918 (with-ir1-environment-from-node call
920 (locall-analyze-component *current-component*))))
922 (values (ref-leaf (continuation-use (basic-combination-fun call)))
925 (let ((info (info :function :info (leaf-source-name leaf))))
927 (values leaf (setf (basic-combination-kind call) info))
928 (values leaf nil)))))))
930 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
931 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
932 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
933 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
934 ;;; syntax check, arg/result type processing, but still call
935 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
936 ;;; and that checking is done by local call analysis.
937 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
938 (declare (type combination call) (type ctype type))
939 (cond ((not (fun-type-p type))
940 (aver (multiple-value-bind (val win)
941 (csubtypep type (specifier-type 'function))
943 (recognize-known-call call ir1-converting-not-optimizing-p))
944 ((valid-fun-use call type
945 :argument-test #'always-subtypep
946 :result-test #'always-subtypep
947 ;; KLUDGE: Common Lisp is such a dynamic
948 ;; language that all we can do here in
949 ;; general is issue a STYLE-WARNING. It
950 ;; would be nice to issue a full WARNING
951 ;; in the special case of of type
952 ;; mismatches within a compilation unit
953 ;; (as in section 3.2.2.3 of the spec)
954 ;; but at least as of sbcl-0.6.11, we
955 ;; don't keep track of whether the
956 ;; mismatched data came from the same
957 ;; compilation unit, so we can't do that.
960 ;; FIXME: Actually, I think we could
961 ;; issue a full WARNING if the call
962 ;; violates a DECLAIM FTYPE.
963 :lossage-fun #'compiler-style-warn
964 :unwinnage-fun #'compiler-note)
965 (assert-call-type call type)
966 (maybe-terminate-block call ir1-converting-not-optimizing-p)
967 (recognize-known-call call ir1-converting-not-optimizing-p))
969 (setf (combination-kind call) :error)
972 ;;; This is called by IR1-OPTIMIZE when the function for a call has
973 ;;; changed. If the call is local, we try to LET-convert it, and
974 ;;; derive the result type. If it is a :FULL call, we validate it
975 ;;; against the type, which recognizes known calls, does inline
976 ;;; expansion, etc. If a call to a predicate in a non-conditional
977 ;;; position or to a function with a source transform, then we
978 ;;; reconvert the form to give IR1 another chance.
979 (defun propagate-fun-change (call)
980 (declare (type combination call))
981 (let ((*compiler-error-context* call)
982 (fun-cont (basic-combination-fun call)))
983 (setf (continuation-reoptimize fun-cont) nil)
984 (case (combination-kind call)
986 (let ((fun (combination-lambda call)))
987 (maybe-let-convert fun)
988 (unless (member (functional-kind fun) '(:let :assignment :deleted))
989 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
991 (multiple-value-bind (leaf info)
992 (validate-call-type call (continuation-type fun-cont) nil)
993 (cond ((functional-p leaf)
994 (convert-call-if-possible
995 (continuation-use (basic-combination-fun call))
998 ((and (leaf-has-source-name-p leaf)
999 (or (info :function :source-transform (leaf-source-name leaf))
1001 (ir1-attributep (fun-info-attributes info)
1003 (let ((dest (continuation-dest (node-cont call))))
1004 (and dest (not (if-p dest)))))))
1005 ;; FIXME: This SYMBOLP is part of a literal
1006 ;; translation of a test in the old CMU CL
1007 ;; source, and it's not quite clear what
1008 ;; the old source meant. Did it mean "has a
1009 ;; valid name"? Or did it mean "is an
1010 ;; ordinary function name, not a SETF
1011 ;; function"? Either way, the old CMU CL
1012 ;; code probably didn't deal with SETF
1013 ;; functions correctly, and neither does
1014 ;; this new SBCL code, and that should be fixed.
1015 (when (symbolp (leaf-source-name leaf))
1016 (let ((dummies (make-gensym-list
1017 (length (combination-args call)))))
1018 (transform-call call
1020 (,(leaf-source-name leaf)
1022 (leaf-source-name leaf))))))))))
1025 ;;;; known function optimization
1027 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
1028 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
1029 ;;; replace it, otherwise add a new one.
1030 (defun record-optimization-failure (node transform args)
1031 (declare (type combination node) (type transform transform)
1032 (type (or fun-type list) args))
1033 (let* ((table (component-failed-optimizations *component-being-compiled*))
1034 (found (assoc transform (gethash node table))))
1036 (setf (cdr found) args)
1037 (push (cons transform args) (gethash node table))))
1040 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
1041 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
1042 ;;; doing the transform for some reason and FLAME is true, then we
1043 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
1044 ;;; finalize to pick up. We return true if the transform failed, and
1045 ;;; thus further transformation should be attempted. We return false
1046 ;;; if either the transform succeeded or was aborted.
1047 (defun ir1-transform (node transform)
1048 (declare (type combination node) (type transform transform))
1049 (let* ((type (transform-type transform))
1050 (fun (transform-function transform))
1051 (constrained (fun-type-p type))
1052 (table (component-failed-optimizations *component-being-compiled*))
1053 (flame (if (transform-important transform)
1054 (policy node (>= speed inhibit-warnings))
1055 (policy node (> speed inhibit-warnings))))
1056 (*compiler-error-context* node))
1057 (cond ((or (not constrained)
1058 (valid-fun-use node type :strict-result t))
1059 (multiple-value-bind (severity args)
1060 (catch 'give-up-ir1-transform
1061 (transform-call node
1063 (combination-fun-source-name node))
1067 (remhash node table)
1070 (setf (combination-kind node) :error)
1072 (apply #'compiler-warn args))
1073 (remhash node table)
1078 (record-optimization-failure node transform args))
1079 (setf (gethash node table)
1080 (remove transform (gethash node table) :key #'car)))
1083 (remhash node table)
1088 :argument-test #'types-equal-or-intersect
1089 :result-test #'values-types-equal-or-intersect))
1090 (record-optimization-failure node transform type)
1095 ;;; When we don't like an IR1 transform, we throw the severity/reason
1098 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1099 ;;; aborting this attempt to transform the call, but admitting the
1100 ;;; possibility that this or some other transform will later succeed.
1101 ;;; If arguments are supplied, they are format arguments for an
1102 ;;; efficiency note.
1104 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1105 ;;; force a normal call to the function at run time. No further
1106 ;;; optimizations will be attempted.
1108 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1109 ;;; delay the transform on the node until later. REASONS specifies
1110 ;;; when the transform will be later retried. The :OPTIMIZE reason
1111 ;;; causes the transform to be delayed until after the current IR1
1112 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1113 ;;; be delayed until after constraint propagation.
1115 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1116 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1117 ;;; do CASE operations on the various REASON values, it might be a
1118 ;;; good idea to go OO, representing the reasons by objects, using
1119 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1120 ;;; SIGNAL instead of THROW.
1121 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1122 (defun give-up-ir1-transform (&rest args)
1123 (throw 'give-up-ir1-transform (values :failure args)))
1124 (defun abort-ir1-transform (&rest args)
1125 (throw 'give-up-ir1-transform (values :aborted args)))
1126 (defun delay-ir1-transform (node &rest reasons)
1127 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1129 (setf *delayed-ir1-transforms*
1130 (acons node reasons *delayed-ir1-transforms*))
1131 (throw 'give-up-ir1-transform :delayed))
1133 (dolist (reason reasons)
1134 (pushnew reason (cdr assoc)))
1135 (throw 'give-up-ir1-transform :delayed)))))
1137 ;;; Clear any delayed transform with no reasons - these should have
1138 ;;; been tried in the last pass. Then remove the reason from the
1139 ;;; delayed transform reasons, and if any become empty then set
1140 ;;; reoptimize flags for the node. Return true if any transforms are
1142 (defun retry-delayed-ir1-transforms (reason)
1143 (setf *delayed-ir1-transforms*
1144 (remove-if-not #'cdr *delayed-ir1-transforms*))
1145 (let ((reoptimize nil))
1146 (dolist (assoc *delayed-ir1-transforms*)
1147 (let ((reasons (remove reason (cdr assoc))))
1148 (setf (cdr assoc) reasons)
1150 (let ((node (car assoc)))
1151 (unless (node-deleted node)
1153 (setf (node-reoptimize node) t)
1154 (let ((block (node-block node)))
1155 (setf (block-reoptimize block) t)
1156 (setf (component-reoptimize (block-component block)) t)))))))
1159 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1160 ;;; environment, and then install it as the function for the call
1161 ;;; NODE. We do local call analysis so that the new function is
1162 ;;; integrated into the control flow.
1164 ;;; We require the original function source name in order to generate
1165 ;;; a meaningful debug name for the lambda we set up. (It'd be
1166 ;;; possible to do this starting from debug names as well as source
1167 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1168 ;;; generality, since source names are always known to our callers.)
1169 (defun transform-call (node res source-name)
1170 (declare (type combination node) (list res))
1171 (aver (and (legal-fun-name-p source-name)
1172 (not (eql source-name '.anonymous.))))
1173 (with-ir1-environment-from-node node
1174 (let ((new-fun (ir1-convert-inline-lambda
1176 :debug-name (debug-namify "LAMBDA-inlined ~A"
1179 "<unknown function>"))))
1180 (ref (continuation-use (combination-fun node))))
1181 (change-ref-leaf ref new-fun)
1182 (setf (combination-kind node) :full)
1183 (locall-analyze-component *current-component*)))
1186 ;;; Replace a call to a foldable function of constant arguments with
1187 ;;; the result of evaluating the form. We insert the resulting
1188 ;;; constant node after the call, stealing the call's continuation. We
1189 ;;; give the call a continuation with no DEST, which should cause it
1190 ;;; and its arguments to go away. If there is an error during the
1191 ;;; evaluation, we give a warning and leave the call alone, making the
1192 ;;; call a :ERROR call.
1194 ;;; If there is more than one value, then we transform the call into a
1196 (defun constant-fold-call (call)
1197 (let ((args (mapcar #'continuation-value (combination-args call)))
1198 (fun-name (combination-fun-source-name call)))
1199 (multiple-value-bind (values win)
1200 (careful-call fun-name
1203 ;; Note: CMU CL had COMPILER-WARN here, and that
1204 ;; seems more natural, but it's probably not.
1206 ;; It's especially not while bug 173 exists:
1209 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1211 ;; can cause constant-folding TYPE-ERRORs (in
1212 ;; #'<=) when END can be proved to be NIL, even
1213 ;; though the code is perfectly legal and safe
1214 ;; because a NIL value of END means that the
1215 ;; #'<= will never be executed.
1217 ;; Moreover, even without bug 173,
1218 ;; quite-possibly-valid code like
1219 ;; (COND ((NONINLINED-PREDICATE END)
1220 ;; (UNLESS (<= END SIZE))
1222 ;; (where NONINLINED-PREDICATE is something the
1223 ;; compiler can't do at compile time, but which
1224 ;; turns out to make the #'<= expression
1225 ;; unreachable when END=NIL) could cause errors
1226 ;; when the compiler tries to constant-fold (<=
1229 ;; So, with or without bug 173, it'd be
1230 ;; unnecessarily evil to do a full
1231 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1232 ;; from COMPILE-FILE) for legal code, so we we
1233 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1234 #'compiler-style-warn
1237 (setf (combination-kind call) :error)
1238 (let ((dummies (make-gensym-list (length args))))
1242 (declare (ignore ,@dummies))
1243 (values ,@(mapcar (lambda (x) `',x) values)))
1247 ;;;; local call optimization
1249 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1250 ;;; the leaf type is a function type, then just leave it alone, since
1251 ;;; TYPE is never going to be more specific than that (and
1252 ;;; TYPE-INTERSECTION would choke.)
1253 (defun propagate-to-refs (leaf type)
1254 (declare (type leaf leaf) (type ctype type))
1255 (let ((var-type (leaf-type leaf)))
1256 (unless (fun-type-p var-type)
1257 (let ((int (type-approx-intersection2 var-type type)))
1258 (when (type/= int var-type)
1259 (setf (leaf-type leaf) int)
1260 (dolist (ref (leaf-refs leaf))
1261 (derive-node-type ref int))))
1264 ;;; Figure out the type of a LET variable that has sets. We compute
1265 ;;; the union of the initial value Type and the types of all the set
1266 ;;; values and to a PROPAGATE-TO-REFS with this type.
1267 (defun propagate-from-sets (var type)
1268 (collect ((res type type-union))
1269 (dolist (set (basic-var-sets var))
1270 (res (continuation-type (set-value set)))
1271 (setf (node-reoptimize set) nil))
1272 (propagate-to-refs var (res)))
1275 ;;; If a LET variable, find the initial value's type and do
1276 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1278 (defun ir1-optimize-set (node)
1279 (declare (type cset node))
1280 (let ((var (set-var node)))
1281 (when (and (lambda-var-p var) (leaf-refs var))
1282 (let ((home (lambda-var-home var)))
1283 (when (eq (functional-kind home) :let)
1284 (let ((iv (let-var-initial-value var)))
1285 (setf (continuation-reoptimize iv) nil)
1286 (propagate-from-sets var (continuation-type iv)))))))
1288 (derive-node-type node (continuation-type (set-value node)))
1291 ;;; Return true if the value of REF will always be the same (and is
1292 ;;; thus legal to substitute.)
1293 (defun constant-reference-p (ref)
1294 (declare (type ref ref))
1295 (let ((leaf (ref-leaf ref)))
1297 ((or constant functional) t)
1299 (null (lambda-var-sets leaf)))
1301 (not (eq (defined-fun-inlinep leaf) :notinline)))
1302 #!+(and (not sb-fluid) (not sb-xc-host))
1304 (case (global-var-kind leaf)
1305 (:global-function (let ((name (leaf-source-name leaf)))
1306 (eq (symbol-package (fun-name-block-name name))
1307 *cl-package*))))))))
1309 ;;; If we have a non-set LET var with a single use, then (if possible)
1310 ;;; replace the variable reference's CONT with the arg continuation.
1311 ;;; This is inhibited when:
1312 ;;; -- CONT has other uses, or
1313 ;;; -- CONT receives multiple values, or
1314 ;;; -- the reference is in a different environment from the variable, or
1315 ;;; -- either continuation has a funky TYPE-CHECK annotation.
1316 ;;; -- the continuations have incompatible assertions, so the new asserted type
1318 ;;; -- the var's DEST has a different policy than the ARG's (think safety).
1320 ;;; We change the REF to be a reference to NIL with unused value, and
1321 ;;; let it be flushed as dead code. A side effect of this substitution
1322 ;;; is to delete the variable.
1323 (defun substitute-single-use-continuation (arg var)
1324 (declare (type continuation arg) (type lambda-var var))
1325 (let* ((ref (first (leaf-refs var)))
1326 (cont (node-cont ref))
1327 (cont-atype (continuation-asserted-type cont))
1328 (cont-ctype (continuation-type-to-check cont))
1329 (dest (continuation-dest cont)))
1330 (when (and (eq (continuation-use cont) ref)
1332 (not (typep dest '(or creturn exit mv-combination)))
1333 (eq (node-home-lambda ref)
1334 (lambda-home (lambda-var-home var)))
1335 (member (continuation-type-check arg) '(t nil))
1336 (member (continuation-type-check cont) '(t nil))
1337 (not (eq (values-type-intersection
1339 (continuation-asserted-type arg))
1341 (eq (lexenv-policy (node-lexenv dest))
1342 (lexenv-policy (node-lexenv (continuation-dest arg)))))
1343 (aver (member (continuation-kind arg)
1344 '(:block-start :deleted-block-start :inside-block)))
1345 (set-continuation-type-assertion arg cont-atype cont-ctype)
1346 (setf (node-derived-type ref) *wild-type*)
1347 (change-ref-leaf ref (find-constant nil))
1348 (substitute-continuation arg cont)
1349 (reoptimize-continuation arg)
1352 ;;; Delete a LET, removing the call and bind nodes, and warning about
1353 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1354 ;;; along right away and delete the REF and then the lambda, since we
1355 ;;; flush the FUN continuation.
1356 (defun delete-let (clambda)
1357 (declare (type clambda clambda))
1358 (aver (functional-letlike-p clambda))
1359 (note-unreferenced-vars clambda)
1360 (let ((call (let-combination clambda)))
1361 (flush-dest (basic-combination-fun call))
1363 (unlink-node (lambda-bind clambda))
1364 (setf (lambda-bind clambda) nil))
1367 ;;; This function is called when one of the arguments to a LET
1368 ;;; changes. We look at each changed argument. If the corresponding
1369 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1370 ;;; consider substituting for the variable, and also propagate
1371 ;;; derived-type information for the arg to all the VAR's refs.
1373 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1374 ;;; subtype of the argument's asserted type. This prevents type
1375 ;;; checking from being defeated, and also ensures that the best
1376 ;;; representation for the variable can be used.
1378 ;;; Substitution of individual references is inhibited if the
1379 ;;; reference is in a different component from the home. This can only
1380 ;;; happen with closures over top level lambda vars. In such cases,
1381 ;;; the references may have already been compiled, and thus can't be
1382 ;;; retroactively modified.
1384 ;;; If all of the variables are deleted (have no references) when we
1385 ;;; are done, then we delete the LET.
1387 ;;; Note that we are responsible for clearing the
1388 ;;; CONTINUATION-REOPTIMIZE flags.
1389 (defun propagate-let-args (call fun)
1390 (declare (type combination call) (type clambda fun))
1391 (loop for arg in (combination-args call)
1392 and var in (lambda-vars fun) do
1393 (when (and arg (continuation-reoptimize arg))
1394 (setf (continuation-reoptimize arg) nil)
1396 ((lambda-var-sets var)
1397 (propagate-from-sets var (continuation-type arg)))
1398 ((let ((use (continuation-use arg)))
1400 (let ((leaf (ref-leaf use)))
1401 (when (and (constant-reference-p use)
1402 (values-subtypep (leaf-type leaf)
1403 (continuation-asserted-type arg)))
1404 (propagate-to-refs var (continuation-type arg))
1405 (let ((use-component (node-component use)))
1408 (cond ((eq (node-component ref) use-component)
1411 (aver (lambda-toplevelish-p (lambda-home fun)))
1415 ((and (null (rest (leaf-refs var)))
1416 (substitute-single-use-continuation arg var)))
1418 (propagate-to-refs var (continuation-type arg))))))
1420 (when (every #'null (combination-args call))
1425 ;;; This function is called when one of the args to a non-LET local
1426 ;;; call changes. For each changed argument corresponding to an unset
1427 ;;; variable, we compute the union of the types across all calls and
1428 ;;; propagate this type information to the var's refs.
1430 ;;; If the function has an XEP, then we don't do anything, since we
1431 ;;; won't discover anything.
1433 ;;; We can clear the Continuation-Reoptimize flags for arguments in
1434 ;;; all calls corresponding to changed arguments in Call, since the
1435 ;;; only use in IR1 optimization of the Reoptimize flag for local call
1436 ;;; args is right here.
1437 (defun propagate-local-call-args (call fun)
1438 (declare (type combination call) (type clambda fun))
1440 (unless (or (functional-entry-fun fun)
1441 (lambda-optional-dispatch fun))
1442 (let* ((vars (lambda-vars fun))
1443 (union (mapcar (lambda (arg var)
1445 (continuation-reoptimize arg)
1446 (null (basic-var-sets var)))
1447 (continuation-type arg)))
1448 (basic-combination-args call)
1450 (this-ref (continuation-use (basic-combination-fun call))))
1452 (dolist (arg (basic-combination-args call))
1454 (setf (continuation-reoptimize arg) nil)))
1456 (dolist (ref (leaf-refs fun))
1457 (let ((dest (continuation-dest (node-cont ref))))
1458 (unless (or (eq ref this-ref) (not dest))
1460 (mapcar (lambda (this-arg old)
1462 (setf (continuation-reoptimize this-arg) nil)
1463 (type-union (continuation-type this-arg) old)))
1464 (basic-combination-args dest)
1467 (mapc (lambda (var type)
1469 (propagate-to-refs var type)))
1474 ;;;; multiple values optimization
1476 ;;; Do stuff to notice a change to a MV combination node. There are
1477 ;;; two main branches here:
1478 ;;; -- If the call is local, then it is already a MV let, or should
1479 ;;; become one. Note that although all :LOCAL MV calls must eventually
1480 ;;; be converted to :MV-LETs, there can be a window when the call
1481 ;;; is local, but has not been LET converted yet. This is because
1482 ;;; the entry-point lambdas may have stray references (in other
1483 ;;; entry points) that have not been deleted yet.
1484 ;;; -- The call is full. This case is somewhat similar to the non-MV
1485 ;;; combination optimization: we propagate return type information and
1486 ;;; notice non-returning calls. We also have an optimization
1487 ;;; which tries to convert MV-CALLs into MV-binds.
1488 (defun ir1-optimize-mv-combination (node)
1489 (ecase (basic-combination-kind node)
1491 (let ((fun-cont (basic-combination-fun node)))
1492 (when (continuation-reoptimize fun-cont)
1493 (setf (continuation-reoptimize fun-cont) nil)
1494 (maybe-let-convert (combination-lambda node))))
1495 (setf (continuation-reoptimize (first (basic-combination-args node))) nil)
1496 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1497 (unless (convert-mv-bind-to-let node)
1498 (ir1-optimize-mv-bind node))))
1500 (let* ((fun (basic-combination-fun node))
1501 (fun-changed (continuation-reoptimize fun))
1502 (args (basic-combination-args node)))
1504 (setf (continuation-reoptimize fun) nil)
1505 (let ((type (continuation-type fun)))
1506 (when (fun-type-p type)
1507 (derive-node-type node (fun-type-returns type))))
1508 (maybe-terminate-block node nil)
1509 (let ((use (continuation-use fun)))
1510 (when (and (ref-p use) (functional-p (ref-leaf use)))
1511 (convert-call-if-possible use node)
1512 (when (eq (basic-combination-kind node) :local)
1513 (maybe-let-convert (ref-leaf use))))))
1514 (unless (or (eq (basic-combination-kind node) :local)
1515 (eq (continuation-fun-name fun) '%throw))
1516 (ir1-optimize-mv-call node))
1518 (setf (continuation-reoptimize arg) nil))))
1522 ;;; Propagate derived type info from the values continuation to the
1524 (defun ir1-optimize-mv-bind (node)
1525 (declare (type mv-combination node))
1526 (let ((arg (first (basic-combination-args node)))
1527 (vars (lambda-vars (combination-lambda node))))
1528 (multiple-value-bind (types nvals)
1529 (values-types (continuation-derived-type arg))
1530 (unless (eq nvals :unknown)
1531 (mapc (lambda (var type)
1532 (if (basic-var-sets var)
1533 (propagate-from-sets var type)
1534 (propagate-to-refs var type)))
1537 (make-list (max (- (length vars) nvals) 0)
1538 :initial-element (specifier-type 'null))))))
1539 (setf (continuation-reoptimize arg) nil))
1542 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1544 ;;; -- The call has only one argument, and
1545 ;;; -- The function has a known fixed number of arguments, or
1546 ;;; -- The argument yields a known fixed number of values.
1548 ;;; What we do is change the function in the MV-CALL to be a lambda
1549 ;;; that "looks like an MV bind", which allows
1550 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1551 ;;; converted (the next time around.) This new lambda just calls the
1552 ;;; actual function with the MV-BIND variables as arguments. Note that
1553 ;;; this new MV bind is not let-converted immediately, as there are
1554 ;;; going to be stray references from the entry-point functions until
1555 ;;; they get deleted.
1557 ;;; In order to avoid loss of argument count checking, we only do the
1558 ;;; transformation according to a known number of expected argument if
1559 ;;; safety is unimportant. We can always convert if we know the number
1560 ;;; of actual values, since the normal call that we build will still
1561 ;;; do any appropriate argument count checking.
1563 ;;; We only attempt the transformation if the called function is a
1564 ;;; constant reference. This allows us to just splice the leaf into
1565 ;;; the new function, instead of trying to somehow bind the function
1566 ;;; expression. The leaf must be constant because we are evaluating it
1567 ;;; again in a different place. This also has the effect of squelching
1568 ;;; multiple warnings when there is an argument count error.
1569 (defun ir1-optimize-mv-call (node)
1570 (let ((fun (basic-combination-fun node))
1571 (*compiler-error-context* node)
1572 (ref (continuation-use (basic-combination-fun node)))
1573 (args (basic-combination-args node)))
1575 (unless (and (ref-p ref) (constant-reference-p ref)
1576 args (null (rest args)))
1577 (return-from ir1-optimize-mv-call))
1579 (multiple-value-bind (min max)
1580 (fun-type-nargs (continuation-type fun))
1582 (multiple-value-bind (types nvals)
1583 (values-types (continuation-derived-type (first args)))
1584 (declare (ignore types))
1585 (if (eq nvals :unknown) nil nvals))))
1588 (when (and min (< total-nvals min))
1590 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1593 (setf (basic-combination-kind node) :error)
1594 (return-from ir1-optimize-mv-call))
1595 (when (and max (> total-nvals max))
1597 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1600 (setf (basic-combination-kind node) :error)
1601 (return-from ir1-optimize-mv-call)))
1603 (let ((count (cond (total-nvals)
1604 ((and (policy node (zerop safety))
1609 (with-ir1-environment-from-node node
1610 (let* ((dums (make-gensym-list count))
1612 (fun (ir1-convert-lambda
1613 `(lambda (&optional ,@dums &rest ,ignore)
1614 (declare (ignore ,ignore))
1615 (funcall ,(ref-leaf ref) ,@dums)))))
1616 (change-ref-leaf ref fun)
1617 (aver (eq (basic-combination-kind node) :full))
1618 (locall-analyze-component *current-component*)
1619 (aver (eq (basic-combination-kind node) :local)))))))))
1623 ;;; (multiple-value-bind
1632 ;;; What we actually do is convert the VALUES combination into a
1633 ;;; normal LET combination calling the original :MV-LET lambda. If
1634 ;;; there are extra args to VALUES, discard the corresponding
1635 ;;; continuations. If there are insufficient args, insert references
1637 (defun convert-mv-bind-to-let (call)
1638 (declare (type mv-combination call))
1639 (let* ((arg (first (basic-combination-args call)))
1640 (use (continuation-use arg)))
1641 (when (and (combination-p use)
1642 (eq (continuation-fun-name (combination-fun use))
1644 (let* ((fun (combination-lambda call))
1645 (vars (lambda-vars fun))
1646 (vals (combination-args use))
1647 (nvars (length vars))
1648 (nvals (length vals)))
1649 (cond ((> nvals nvars)
1650 (mapc #'flush-dest (subseq vals nvars))
1651 (setq vals (subseq vals 0 nvars)))
1653 (with-ir1-environment-from-node use
1654 (let ((node-prev (node-prev use)))
1655 (setf (node-prev use) nil)
1656 (setf (continuation-next node-prev) nil)
1657 (collect ((res vals))
1658 (loop as cont = (make-continuation use)
1659 and prev = node-prev then cont
1660 repeat (- nvars nvals)
1661 do (reference-constant prev cont nil)
1664 (link-node-to-previous-continuation use
1665 (car (last vals)))))))
1666 (setf (combination-args use) vals)
1667 (flush-dest (combination-fun use))
1668 (let ((fun-cont (basic-combination-fun call)))
1669 (setf (continuation-dest fun-cont) use)
1670 (setf (combination-fun use) fun-cont)
1671 (setf (continuation-%externally-checkable-type fun-cont) nil))
1672 (setf (combination-kind use) :local)
1673 (setf (functional-kind fun) :let)
1674 (flush-dest (first (basic-combination-args call)))
1677 (reoptimize-continuation (first vals)))
1678 (propagate-to-args use fun))
1682 ;;; (values-list (list x y z))
1687 ;;; In implementation, this is somewhat similar to
1688 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1689 ;;; args of the VALUES-LIST call, flushing the old argument
1690 ;;; continuation (allowing the LIST to be flushed.)
1691 (defoptimizer (values-list optimizer) ((list) node)
1692 (let ((use (continuation-use list)))
1693 (when (and (combination-p use)
1694 (eq (continuation-fun-name (combination-fun use))
1696 (change-ref-leaf (continuation-use (combination-fun node))
1697 (find-free-fun 'values "in a strange place"))
1698 (setf (combination-kind node) :full)
1699 (let ((args (combination-args use)))
1701 (setf (continuation-dest arg) node)
1702 (setf (continuation-%externally-checkable-type arg) nil))
1703 (setf (combination-args use) nil)
1705 (setf (combination-args node) args))
1708 ;;; If VALUES appears in a non-MV context, then effectively convert it
1709 ;;; to a PROG1. This allows the computation of the additional values
1710 ;;; to become dead code.
1711 (deftransform values ((&rest vals) * * :node node)
1712 (when (typep (continuation-dest (node-cont node))
1713 '(or creturn exit mv-combination))
1714 (give-up-ir1-transform))
1715 (setf (node-derived-type node) *wild-type*)
1717 (let ((dummies (make-gensym-list (length (cdr vals)))))
1718 `(lambda (val ,@dummies)
1719 (declare (ignore ,@dummies))