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 ;;;; interface routines used by optimizers
124 ;;; This function is called by optimizers to indicate that something
125 ;;; interesting has happened to the value of Cont. Optimizers must
126 ;;; make sure that they don't call for reoptimization when nothing has
127 ;;; happened, since optimization will fail to terminate.
129 ;;; We clear any cached type for the continuation and set the
130 ;;; reoptimize flags on everything in sight, unless the continuation
131 ;;; is deleted (in which case we do nothing.)
133 ;;; Since this can get called during IR1 conversion, we have to be
134 ;;; careful not to fly into space when the Dest's Prev is missing.
135 (defun reoptimize-continuation (cont)
136 (declare (type continuation cont))
137 (unless (member (continuation-kind cont) '(:deleted :unused))
138 (setf (continuation-%derived-type cont) nil)
139 (let ((dest (continuation-dest cont)))
141 (setf (continuation-reoptimize cont) t)
142 (setf (node-reoptimize dest) t)
143 (let ((prev (node-prev dest)))
145 (let* ((block (continuation-block prev))
146 (component (block-component block)))
147 (when (typep dest 'cif)
148 (setf (block-test-modified block) t))
149 (setf (block-reoptimize block) t)
150 (setf (component-reoptimize component) t))))))
152 (setf (block-type-check (node-block node)) t)))
155 ;;; Annotate Node to indicate that its result has been proven to be
156 ;;; typep to RType. After IR1 conversion has happened, this is the
157 ;;; only correct way to supply information discovered about a node's
158 ;;; type. If you screw with the Node-Derived-Type directly, then
159 ;;; information may be lost and reoptimization may not happen.
161 ;;; What we do is intersect Rtype with Node's Derived-Type. If the
162 ;;; intersection is different from the old type, then we do a
163 ;;; Reoptimize-Continuation on the Node-Cont.
164 (defun derive-node-type (node rtype)
165 (declare (type node node) (type ctype rtype))
166 (let ((node-type (node-derived-type node)))
167 (unless (eq node-type rtype)
168 (let ((int (values-type-intersection node-type rtype)))
169 (when (type/= node-type int)
170 (when (and *check-consistency*
171 (eq int *empty-type*)
172 (not (eq rtype *empty-type*)))
173 (let ((*compiler-error-context* node))
175 "New inferred type ~S conflicts with old type:~
176 ~% ~S~%*** possible internal error? Please report this."
177 (type-specifier rtype) (type-specifier node-type))))
178 (setf (node-derived-type node) int)
179 (reoptimize-continuation (node-cont node))))))
182 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
183 ;;; error for CONT's value not to be TYPEP to TYPE. If we improve the
184 ;;; assertion, we set TYPE-CHECK and TYPE-ASSERTED to guarantee that
185 ;;; the new assertion will be checked.
186 (defun assert-continuation-type (cont type)
187 (declare (type continuation cont) (type ctype type))
188 (let ((cont-type (continuation-asserted-type cont)))
189 (unless (eq cont-type type)
190 (let ((int (values-type-intersection cont-type type)))
191 (when (type/= cont-type int)
192 (setf (continuation-asserted-type cont) int)
194 (setf (block-attributep (block-flags (node-block node))
195 type-check type-asserted)
197 (reoptimize-continuation cont)))))
200 ;;; Assert that CALL is to a function of the specified TYPE. It is
201 ;;; assumed that the call is legal and has only constants in the
202 ;;; keyword positions.
203 (defun assert-call-type (call type)
204 (declare (type combination call) (type fun-type type))
205 (derive-node-type call (fun-type-returns type))
206 (let ((args (combination-args call)))
207 (dolist (req (fun-type-required type))
208 (when (null args) (return-from assert-call-type))
209 (let ((arg (pop args)))
210 (assert-continuation-type arg req)))
211 (dolist (opt (fun-type-optional type))
212 (when (null args) (return-from assert-call-type))
213 (let ((arg (pop args)))
214 (assert-continuation-type arg opt)))
216 (let ((rest (fun-type-rest type)))
219 (assert-continuation-type arg rest))))
221 (dolist (key (fun-type-keywords type))
222 (let ((name (key-info-name key)))
223 (do ((arg args (cddr arg)))
225 (when (eq (continuation-value (first arg)) name)
226 (assert-continuation-type
227 (second arg) (key-info-type key)))))))
232 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
233 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
234 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
235 ;;; we are done, then another iteration would be beneficial.
236 (defun ir1-optimize (component)
237 (declare (type component component))
238 (setf (component-reoptimize component) nil)
239 (do-blocks (block component)
241 ((or (block-delete-p block)
242 (null (block-pred block))
243 (eq (functional-kind (block-home-lambda block)) :deleted))
244 (delete-block block))
247 (let ((succ (block-succ block)))
248 (unless (and succ (null (rest succ)))
251 (let ((last (block-last block)))
254 (flush-dest (if-test last))
255 (when (unlink-node last)
258 (when (maybe-delete-exit last)
261 (unless (join-successor-if-possible block)
264 (when (and (block-reoptimize block) (block-component block))
265 (aver (not (block-delete-p block)))
266 (ir1-optimize-block block))
268 ;; We delete blocks when there is either no predecessor or the
269 ;; block is in a lambda that has been deleted. These blocks
270 ;; would eventually be deleted by DFO recomputation, but doing
271 ;; it here immediately makes the effect available to IR1
273 (when (and (block-flush-p block) (block-component block))
274 (aver (not (block-delete-p block)))
275 (flush-dead-code block)))))
279 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
282 ;;; Note that although they are cleared here, REOPTIMIZE flags might
283 ;;; still be set upon return from this function, meaning that further
284 ;;; optimization is wanted (as a consequence of optimizations we did).
285 (defun ir1-optimize-block (block)
286 (declare (type cblock block))
287 ;; We clear the node and block REOPTIMIZE flags before doing the
288 ;; optimization, not after. This ensures that the node or block will
289 ;; be reoptimized if necessary.
290 (setf (block-reoptimize block) nil)
291 (do-nodes (node cont block :restart-p t)
292 (when (node-reoptimize node)
293 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
294 (setf (node-reoptimize node) nil)
298 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
299 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
300 ;; any argument changes.
301 (ir1-optimize-combination node))
303 (ir1-optimize-if node))
305 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
306 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
307 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
309 (setf (node-reoptimize node) t)
310 (ir1-optimize-return node))
312 (ir1-optimize-mv-combination node))
314 ;; With an EXIT, we derive the node's type from the VALUE's
315 ;; type. We don't propagate CONT's assertion to the VALUE,
316 ;; since if we did, this would move the checking of CONT's
317 ;; assertion to the exit. This wouldn't work with CATCH and
318 ;; UWP, where the EXIT node is just a placeholder for the
319 ;; actual unknown exit.
320 (let ((value (exit-value node)))
322 (derive-node-type node (continuation-derived-type value)))))
324 (ir1-optimize-set node)))))
327 ;;; Try to join with a successor block. If we succeed, we return true,
329 (defun join-successor-if-possible (block)
330 (declare (type cblock block))
331 (let ((next (first (block-succ block))))
332 (when (block-start next)
333 (let* ((last (block-last block))
334 (last-cont (node-cont last))
335 (next-cont (block-start next)))
336 (cond (;; We cannot combine with a successor block if:
338 ;; The successor has more than one predecessor.
339 (rest (block-pred next))
340 ;; The last node's CONT is also used somewhere else.
341 (not (eq (continuation-use last-cont) last))
342 ;; The successor is the current block (infinite loop).
344 ;; The next block has a different cleanup, and thus
345 ;; we may want to insert cleanup code between the
346 ;; two blocks at some point.
347 (not (eq (block-end-cleanup block)
348 (block-start-cleanup next)))
349 ;; The next block has a different home lambda, and
350 ;; thus the control transfer is a non-local exit.
351 (not (eq (block-home-lambda block)
352 (block-home-lambda next))))
354 ;; Joining is easy when the successor's START
355 ;; continuation is the same from our LAST's CONT.
356 ((eq last-cont next-cont)
357 (join-blocks block next)
359 ;; If they differ, then we can still join when the last
360 ;; continuation has no next and the next continuation
362 ((and (null (block-start-uses next))
363 (eq (continuation-kind last-cont) :inside-block))
364 ;; In this case, we replace the next
365 ;; continuation with the last before joining the blocks.
366 (let ((next-node (continuation-next next-cont)))
367 ;; If NEXT-CONT does have a dest, it must be
368 ;; unreachable, since there are no USES.
369 ;; DELETE-CONTINUATION will mark the dest block as
370 ;; DELETE-P [and also this block, unless it is no
371 ;; longer backward reachable from the dest block.]
372 (delete-continuation next-cont)
373 (setf (node-prev next-node) last-cont)
374 (setf (continuation-next last-cont) next-node)
375 (setf (block-start next) last-cont)
376 (join-blocks block next))
381 ;;; Join together two blocks which have the same ending/starting
382 ;;; continuation. The code in BLOCK2 is moved into BLOCK1 and BLOCK2
383 ;;; is deleted from the DFO. We combine the optimize flags for the two
384 ;;; blocks so that any indicated optimization gets done.
385 (defun join-blocks (block1 block2)
386 (declare (type cblock block1 block2))
387 (let* ((last (block-last block2))
388 (last-cont (node-cont last))
389 (succ (block-succ block2))
390 (start2 (block-start block2)))
391 (do ((cont start2 (node-cont (continuation-next cont))))
393 (when (eq (continuation-kind last-cont) :inside-block)
394 (setf (continuation-block last-cont) block1)))
395 (setf (continuation-block cont) block1))
397 (unlink-blocks block1 block2)
399 (unlink-blocks block2 block)
400 (link-blocks block1 block))
402 (setf (block-last block1) last)
403 (setf (continuation-kind start2) :inside-block))
405 (setf (block-flags block1)
406 (attributes-union (block-flags block1)
408 (block-attributes type-asserted test-modified)))
410 (let ((next (block-next block2))
411 (prev (block-prev block2)))
412 (setf (block-next prev) next)
413 (setf (block-prev next) prev))
417 ;;; Delete any nodes in BLOCK whose value is unused and which have no
418 ;;; side effects. We can delete sets of lexical variables when the set
419 ;;; variable has no references.
420 (defun flush-dead-code (block)
421 (declare (type cblock block))
422 (do-nodes-backwards (node cont block)
423 (unless (continuation-dest cont)
429 (let ((info (combination-kind node)))
430 (when (fun-info-p info)
431 (let ((attr (fun-info-attributes info)))
432 (when (and (ir1-attributep attr flushable)
433 ;; ### For now, don't delete potentially
434 ;; flushable calls when they have the CALL
435 ;; attribute. Someday we should look at the
436 ;; functional args to determine if they have
438 (not (ir1-attributep attr call)))
439 (flush-dest (combination-fun node))
440 (dolist (arg (combination-args node))
442 (unlink-node node))))))
444 (when (eq (basic-combination-kind node) :local)
445 (let ((fun (combination-lambda node)))
446 (when (dolist (var (lambda-vars fun) t)
447 (when (or (leaf-refs var)
448 (lambda-var-sets var))
450 (flush-dest (first (basic-combination-args node)))
453 (let ((value (exit-value node)))
456 (setf (exit-value node) nil))))
458 (let ((var (set-var node)))
459 (when (and (lambda-var-p var)
460 (null (leaf-refs var)))
461 (flush-dest (set-value node))
462 (setf (basic-var-sets var)
463 (delete node (basic-var-sets var)))
464 (unlink-node node)))))))
466 (setf (block-flush-p block) nil)
469 ;;;; local call return type propagation
471 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
472 ;;; flag set. It iterates over the uses of the RESULT, looking for
473 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
474 ;;; call, then we union its type together with the types of other such
475 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
476 ;;; type with the RESULT's asserted type. We can make this
477 ;;; intersection now (potentially before type checking) because this
478 ;;; assertion on the result will eventually be checked (if
481 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
482 ;;; combination, which may change the succesor of the call to be the
483 ;;; called function, and if so, checks if the call can become an
484 ;;; assignment. If we convert to an assignment, we abort, since the
485 ;;; RETURN has been deleted.
486 (defun find-result-type (node)
487 (declare (type creturn node))
488 (let ((result (return-result node)))
489 (collect ((use-union *empty-type* values-type-union))
490 (do-uses (use result)
491 (cond ((and (basic-combination-p use)
492 (eq (basic-combination-kind use) :local))
493 (aver (eq (lambda-tail-set (node-home-lambda use))
494 (lambda-tail-set (combination-lambda use))))
495 (when (combination-p use)
496 (when (nth-value 1 (maybe-convert-tail-local-call use))
497 (return-from find-result-type (values)))))
499 (use-union (node-derived-type use)))))
500 (let ((int (values-type-intersection
501 (continuation-asserted-type result)
503 (setf (return-result-type node) int))))
506 ;;; Do stuff to realize that something has changed about the value
507 ;;; delivered to a return node. Since we consider the return values of
508 ;;; all functions in the tail set to be equivalent, this amounts to
509 ;;; bringing the entire tail set up to date. We iterate over the
510 ;;; returns for all the functions in the tail set, reanalyzing them
511 ;;; all (not treating Node specially.)
513 ;;; When we are done, we check whether the new type is different from
514 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
515 ;;; all the continuations for references to functions in the tail set.
516 ;;; This will cause IR1-OPTIMIZE-COMBINATION to derive the new type as
517 ;;; the results of the calls.
518 (defun ir1-optimize-return (node)
519 (declare (type creturn node))
520 (let* ((tails (lambda-tail-set (return-lambda node)))
521 (funs (tail-set-funs tails)))
522 (collect ((res *empty-type* values-type-union))
524 (let ((return (lambda-return fun)))
526 (when (node-reoptimize return)
527 (setf (node-reoptimize return) nil)
528 (find-result-type return))
529 (res (return-result-type return)))))
531 (when (type/= (res) (tail-set-type tails))
532 (setf (tail-set-type tails) (res))
533 (dolist (fun (tail-set-funs tails))
534 (dolist (ref (leaf-refs fun))
535 (reoptimize-continuation (node-cont ref)))))))
541 ;;; If the test has multiple uses, replicate the node when possible.
542 ;;; Also check whether the predicate is known to be true or false,
543 ;;; deleting the IF node in favor of the appropriate branch when this
545 (defun ir1-optimize-if (node)
546 (declare (type cif node))
547 (let ((test (if-test node))
548 (block (node-block node)))
550 (when (and (eq (block-start block) test)
551 (eq (continuation-next test) node)
552 (rest (block-start-uses block)))
554 (when (immediately-used-p test use)
555 (convert-if-if use node)
556 (when (continuation-use test) (return)))))
558 (let* ((type (continuation-type test))
560 (cond ((constant-continuation-p test)
561 (if (continuation-value test)
562 (if-alternative node)
563 (if-consequent node)))
564 ((not (types-equal-or-intersect type (specifier-type 'null)))
565 (if-alternative node))
566 ((type= type (specifier-type 'null))
567 (if-consequent node)))))
570 (when (rest (block-succ block))
571 (unlink-blocks block victim))
572 (setf (component-reanalyze (node-component node)) t)
573 (unlink-node node))))
576 ;;; Create a new copy of an IF node that tests the value of the node
577 ;;; USE. The test must have >1 use, and must be immediately used by
578 ;;; USE. NODE must be the only node in its block (implying that
579 ;;; block-start = if-test).
581 ;;; This optimization has an effect semantically similar to the
582 ;;; source-to-source transformation:
583 ;;; (IF (IF A B C) D E) ==>
584 ;;; (IF A (IF B D E) (IF C D E))
586 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
587 ;;; node so that dead code deletion notes will definitely not consider
588 ;;; either node to be part of the original source. One node might
589 ;;; become unreachable, resulting in a spurious note.
590 (defun convert-if-if (use node)
591 (declare (type node use) (type cif node))
592 (with-ir1-environment-from-node node
593 (let* ((block (node-block node))
594 (test (if-test node))
595 (cblock (if-consequent node))
596 (ablock (if-alternative node))
597 (use-block (node-block use))
598 (dummy-cont (make-continuation))
599 (new-cont (make-continuation))
600 (new-node (make-if :test new-cont
602 :alternative ablock))
603 (new-block (continuation-starts-block new-cont)))
604 (link-node-to-previous-continuation new-node new-cont)
605 (setf (continuation-dest new-cont) new-node)
606 (add-continuation-use new-node dummy-cont)
607 (setf (block-last new-block) new-node)
609 (unlink-blocks use-block block)
610 (delete-continuation-use use)
611 (add-continuation-use use new-cont)
612 (link-blocks use-block new-block)
614 (link-blocks new-block cblock)
615 (link-blocks new-block ablock)
617 (push "<IF Duplication>" (node-source-path node))
618 (push "<IF Duplication>" (node-source-path new-node))
620 (reoptimize-continuation test)
621 (reoptimize-continuation new-cont)
622 (setf (component-reanalyze *current-component*) t)))
625 ;;;; exit IR1 optimization
627 ;;; This function attempts to delete an exit node, returning true if
628 ;;; it deletes the block as a consequence:
629 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
630 ;;; anything, since there is nothing to be done.
631 ;;; -- If the exit node and its ENTRY have the same home lambda then
632 ;;; we know the exit is local, and can delete the exit. We change
633 ;;; uses of the Exit-Value to be uses of the original continuation,
634 ;;; then unlink the node. If the exit is to a TR context, then we
635 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
636 ;;; their value to this exit.
637 ;;; -- If there is no value (as in a GO), then we skip the value
640 ;;; This function is also called by environment analysis, since it
641 ;;; wants all exits to be optimized even if normal optimization was
643 (defun maybe-delete-exit (node)
644 (declare (type exit node))
645 (let ((value (exit-value node))
646 (entry (exit-entry node))
647 (cont (node-cont node)))
649 (eq (node-home-lambda node) (node-home-lambda entry)))
650 (setf (entry-exits entry) (delete node (entry-exits entry)))
655 (when (return-p (continuation-dest cont))
657 (when (and (basic-combination-p use)
658 (eq (basic-combination-kind use) :local))
660 (substitute-continuation-uses cont value)
661 (dolist (merge (merges))
662 (merge-tail-sets merge))))))))
664 ;;;; combination IR1 optimization
666 ;;; Report as we try each transform?
668 (defvar *show-transforms-p* nil)
670 ;;; Do IR1 optimizations on a COMBINATION node.
671 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
672 (defun ir1-optimize-combination (node)
673 (when (continuation-reoptimize (basic-combination-fun node))
674 (propagate-fun-change node))
675 (let ((args (basic-combination-args node))
676 (kind (basic-combination-kind node)))
679 (let ((fun (combination-lambda node)))
680 (if (eq (functional-kind fun) :let)
681 (propagate-let-args node fun)
682 (propagate-local-call-args node fun))))
686 (setf (continuation-reoptimize arg) nil))))
690 (setf (continuation-reoptimize arg) nil)))
692 (let ((attr (fun-info-attributes kind)))
693 (when (and (ir1-attributep attr foldable)
694 ;; KLUDGE: The next test could be made more sensitive,
695 ;; only suppressing constant-folding of functions with
696 ;; CALL attributes when they're actually passed
697 ;; function arguments. -- WHN 19990918
698 (not (ir1-attributep attr call))
699 (every #'constant-continuation-p args)
700 (continuation-dest (node-cont node))
701 ;; Even if the function is foldable in principle,
702 ;; it might be one of our low-level
703 ;; implementation-specific functions. Such
704 ;; functions don't necessarily exist at runtime on
705 ;; a plain vanilla ANSI Common Lisp
706 ;; cross-compilation host, in which case the
707 ;; cross-compiler can't fold it because the
708 ;; cross-compiler doesn't know how to evaluate it.
710 (fboundp (combination-fun-source-name node)))
711 (constant-fold-call node)
712 (return-from ir1-optimize-combination)))
714 (let ((fun (fun-info-derive-type kind)))
716 (let ((res (funcall fun node)))
718 (derive-node-type node res)
719 (maybe-terminate-block node nil)))))
721 (let ((fun (fun-info-optimizer kind)))
722 (unless (and fun (funcall fun node))
723 (dolist (x (fun-info-transforms kind))
725 (when *show-transforms-p*
726 (let* ((cont (basic-combination-fun node))
727 (fname (continuation-fun-name cont t)))
728 (/show "trying transform" x (transform-function x) "for" fname)))
729 (unless (ir1-transform node x)
731 (when *show-transforms-p*
732 (/show "quitting because IR1-TRANSFORM result was NIL"))
737 ;;; If CALL is to a function that doesn't return (i.e. return type is
738 ;;; NIL), then terminate the block there, and link it to the component
739 ;;; tail. We also change the call's CONT to be a dummy continuation to
740 ;;; prevent the use from confusing things.
742 ;;; Except when called during IR1 [FIXME: What does this mean? Except
743 ;;; during IR1 conversion? What about IR1 optimization?], we delete
744 ;;; the continuation if it has no other uses. (If it does have other
745 ;;; uses, we reoptimize.)
747 ;;; Termination on the basis of a continuation type assertion is
749 ;;; -- The continuation is deleted (hence the assertion is spurious), or
750 ;;; -- We are in IR1 conversion (where THE assertions are subject to
752 (defun maybe-terminate-block (call ir1-converting-not-optimizing-p)
753 (declare (type basic-combination call))
754 (let* ((block (node-block call))
755 (cont (node-cont call))
756 (tail (component-tail (block-component block)))
757 (succ (first (block-succ block))))
758 (unless (or (and (eq call (block-last block)) (eq succ tail))
759 (block-delete-p block))
760 (when (or (and (eq (continuation-asserted-type cont) *empty-type*)
761 (not (or ir1-converting-not-optimizing-p
762 (eq (continuation-kind cont) :deleted))))
763 (eq (node-derived-type call) *empty-type*))
764 (cond (ir1-converting-not-optimizing-p
765 (delete-continuation-use call)
768 (aver (and (eq (block-last block) call)
769 (eq (continuation-kind cont) :block-start))))
771 (setf (block-last block) call)
772 (link-blocks block (continuation-starts-block cont)))))
774 (node-ends-block call)
775 (delete-continuation-use call)
776 (if (eq (continuation-kind cont) :unused)
777 (delete-continuation cont)
778 (reoptimize-continuation cont))))
780 (unlink-blocks block (first (block-succ block)))
781 (setf (component-reanalyze (block-component block)) t)
782 (aver (not (block-succ block)))
783 (link-blocks block tail)
784 (add-continuation-use call (make-continuation))
787 ;;; This is called both by IR1 conversion and IR1 optimization when
788 ;;; they have verified the type signature for the call, and are
789 ;;; wondering if something should be done to special-case the call. If
790 ;;; CALL is a call to a global function, then see whether it defined
792 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
793 ;;; the expansion and change the call to call it. Expansion is
794 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
795 ;;; true, we never expand, since this function has already been
796 ;;; converted. Local call analysis will duplicate the definition
797 ;;; if necessary. We claim that the parent form is LABELS for
798 ;;; context declarations, since we don't want it to be considered
799 ;;; a real global function.
800 ;;; -- If it is a known function, mark it as such by setting the KIND.
802 ;;; We return the leaf referenced (NIL if not a leaf) and the
803 ;;; FUN-INFO assigned.
805 ;;; FIXME: The IR1-CONVERTING-NOT-OPTIMIZING-P argument is what the
806 ;;; old CMU CL code called IR1-P, without explanation. My (WHN
807 ;;; 2002-01-09) tentative understanding of it is that we can call this
808 ;;; operation either in initial IR1 conversion or in later IR1
809 ;;; optimization, and it tells which is which. But it would be good
810 ;;; for someone who really understands it to check whether this is
812 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
813 (declare (type combination call))
814 (let* ((ref (continuation-use (basic-combination-fun call)))
815 (leaf (when (ref-p ref) (ref-leaf ref)))
816 (inlinep (if (defined-fun-p leaf)
817 (defined-fun-inlinep leaf)
820 ((eq inlinep :notinline) (values nil nil))
821 ((not (and (global-var-p leaf)
822 (eq (global-var-kind leaf) :global-function)))
827 ((nil :maybe-inline) (policy call (zerop space))))
829 (defined-fun-inline-expansion leaf)
830 (let ((fun (defined-fun-functional leaf)))
832 (and (eq inlinep :inline) (functional-kind fun))))
833 (inline-expansion-ok call))
834 (flet (;; FIXME: Is this what the old CMU CL internal documentation
835 ;; called semi-inlining? A more descriptive name would
836 ;; be nice. -- WHN 2002-01-07
838 (let ((res (ir1-convert-lambda-for-defun
839 (defined-fun-inline-expansion leaf)
841 #'ir1-convert-inline-lambda)))
842 (setf (defined-fun-functional leaf) res)
843 (change-ref-leaf ref res))))
844 (if ir1-converting-not-optimizing-p
846 (with-ir1-environment-from-node call
848 (locall-analyze-component *current-component*))))
850 (values (ref-leaf (continuation-use (basic-combination-fun call)))
853 (let ((info (info :function :info (leaf-source-name leaf))))
855 (values leaf (setf (basic-combination-kind call) info))
856 (values leaf nil)))))))
858 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
859 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
860 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
861 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
862 ;;; syntax check, arg/result type processing, but still call
863 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
864 ;;; and that checking is done by local call analysis.
865 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
866 (declare (type combination call) (type ctype type))
867 (cond ((not (fun-type-p type))
868 (aver (multiple-value-bind (val win)
869 (csubtypep type (specifier-type 'function))
871 (recognize-known-call call ir1-converting-not-optimizing-p))
872 ((valid-fun-use call type
873 :argument-test #'always-subtypep
874 :result-test #'always-subtypep
875 ;; KLUDGE: Common Lisp is such a dynamic
876 ;; language that all we can do here in
877 ;; general is issue a STYLE-WARNING. It
878 ;; would be nice to issue a full WARNING
879 ;; in the special case of of type
880 ;; mismatches within a compilation unit
881 ;; (as in section 3.2.2.3 of the spec)
882 ;; but at least as of sbcl-0.6.11, we
883 ;; don't keep track of whether the
884 ;; mismatched data came from the same
885 ;; compilation unit, so we can't do that.
888 ;; FIXME: Actually, I think we could
889 ;; issue a full WARNING if the call
890 ;; violates a DECLAIM FTYPE.
891 :lossage-fun #'compiler-style-warn
892 :unwinnage-fun #'compiler-note)
893 (assert-call-type call type)
894 (maybe-terminate-block call ir1-converting-not-optimizing-p)
895 (recognize-known-call call ir1-converting-not-optimizing-p))
897 (setf (combination-kind call) :error)
900 ;;; This is called by IR1-OPTIMIZE when the function for a call has
901 ;;; changed. If the call is local, we try to LET-convert it, and
902 ;;; derive the result type. If it is a :FULL call, we validate it
903 ;;; against the type, which recognizes known calls, does inline
904 ;;; expansion, etc. If a call to a predicate in a non-conditional
905 ;;; position or to a function with a source transform, then we
906 ;;; reconvert the form to give IR1 another chance.
907 (defun propagate-fun-change (call)
908 (declare (type combination call))
909 (let ((*compiler-error-context* call)
910 (fun-cont (basic-combination-fun call)))
911 (setf (continuation-reoptimize fun-cont) nil)
912 (case (combination-kind call)
914 (let ((fun (combination-lambda call)))
915 (maybe-let-convert fun)
916 (unless (member (functional-kind fun) '(:let :assignment :deleted))
917 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
919 (multiple-value-bind (leaf info)
920 (validate-call-type call (continuation-type fun-cont) nil)
921 (cond ((functional-p leaf)
922 (convert-call-if-possible
923 (continuation-use (basic-combination-fun call))
926 ((or (info :function :source-transform (leaf-source-name leaf))
928 (ir1-attributep (fun-info-attributes info)
930 (let ((dest (continuation-dest (node-cont call))))
931 (and dest (not (if-p dest))))))
932 (when (and (leaf-has-source-name-p leaf)
933 ;; FIXME: This SYMBOLP is part of a literal
934 ;; translation of a test in the old CMU CL
935 ;; source, and it's not quite clear what
936 ;; the old source meant. Did it mean "has a
937 ;; valid name"? Or did it mean "is an
938 ;; ordinary function name, not a SETF
939 ;; function"? Either way, the old CMU CL
940 ;; code probably didn't deal with SETF
941 ;; functions correctly, and neither does
942 ;; this new SBCL code, and that should be fixed.
943 (symbolp (leaf-source-name leaf)))
944 (let ((dummies (make-gensym-list (length
945 (combination-args call)))))
948 (,(leaf-source-name leaf)
950 (leaf-source-name leaf))))))))))
953 ;;;; known function optimization
955 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
956 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
957 ;;; replace it, otherwise add a new one.
958 (defun record-optimization-failure (node transform args)
959 (declare (type combination node) (type transform transform)
960 (type (or fun-type list) args))
961 (let* ((table (component-failed-optimizations *component-being-compiled*))
962 (found (assoc transform (gethash node table))))
964 (setf (cdr found) args)
965 (push (cons transform args) (gethash node table))))
968 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
969 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
970 ;;; doing the transform for some reason and FLAME is true, then we
971 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
972 ;;; finalize to pick up. We return true if the transform failed, and
973 ;;; thus further transformation should be attempted. We return false
974 ;;; if either the transform succeeded or was aborted.
975 (defun ir1-transform (node transform)
976 (declare (type combination node) (type transform transform))
977 (let* ((type (transform-type transform))
978 (fun (transform-function transform))
979 (constrained (fun-type-p type))
980 (table (component-failed-optimizations *component-being-compiled*))
981 (flame (if (transform-important transform)
982 (policy node (>= speed inhibit-warnings))
983 (policy node (> speed inhibit-warnings))))
984 (*compiler-error-context* node))
985 (cond ((not (member (transform-when transform)
987 ;; FIXME: Make sure that there's a transform for
988 ;; (MEMBER SYMBOL ..) into MEMQ.
989 ;; FIXME: Note that when/if I make SHARE operation to shared
990 ;; constant data between objects in the system, remember that a
991 ;; SHAREd list, or other SHAREd compound object, can be processed
992 ;; recursively, so that e.g. the two lists above can share their
993 ;; '(:BOTH) tail sublists.
994 (let ((when (transform-when transform)))
995 (not (or (eq when :both)
998 ((or (not constrained)
999 (valid-fun-use node type :strict-result t))
1000 (multiple-value-bind (severity args)
1001 (catch 'give-up-ir1-transform
1002 (transform-call node
1004 (combination-fun-source-name node))
1008 (remhash node table)
1011 (setf (combination-kind node) :error)
1013 (apply #'compiler-warn args))
1014 (remhash node table)
1019 (record-optimization-failure node transform args))
1020 (setf (gethash node table)
1021 (remove transform (gethash node table) :key #'car)))
1024 (remhash node table)
1029 :argument-test #'types-equal-or-intersect
1030 :result-test #'values-types-equal-or-intersect))
1031 (record-optimization-failure node transform type)
1036 ;;; When we don't like an IR1 transform, we throw the severity/reason
1039 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1040 ;;; aborting this attempt to transform the call, but admitting the
1041 ;;; possibility that this or some other transform will later succeed.
1042 ;;; If arguments are supplied, they are format arguments for an
1043 ;;; efficiency note.
1045 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1046 ;;; force a normal call to the function at run time. No further
1047 ;;; optimizations will be attempted.
1049 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1050 ;;; delay the transform on the node until later. REASONS specifies
1051 ;;; when the transform will be later retried. The :OPTIMIZE reason
1052 ;;; causes the transform to be delayed until after the current IR1
1053 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1054 ;;; be delayed until after constraint propagation.
1056 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1057 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1058 ;;; do CASE operations on the various REASON values, it might be a
1059 ;;; good idea to go OO, representing the reasons by objects, using
1060 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1061 ;;; SIGNAL instead of THROW.
1062 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1063 (defun give-up-ir1-transform (&rest args)
1064 (throw 'give-up-ir1-transform (values :failure args)))
1065 (defun abort-ir1-transform (&rest args)
1066 (throw 'give-up-ir1-transform (values :aborted args)))
1067 (defun delay-ir1-transform (node &rest reasons)
1068 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1070 (setf *delayed-ir1-transforms*
1071 (acons node reasons *delayed-ir1-transforms*))
1072 (throw 'give-up-ir1-transform :delayed))
1074 (dolist (reason reasons)
1075 (pushnew reason (cdr assoc)))
1076 (throw 'give-up-ir1-transform :delayed)))))
1078 ;;; Clear any delayed transform with no reasons - these should have
1079 ;;; been tried in the last pass. Then remove the reason from the
1080 ;;; delayed transform reasons, and if any become empty then set
1081 ;;; reoptimize flags for the node. Return true if any transforms are
1083 (defun retry-delayed-ir1-transforms (reason)
1084 (setf *delayed-ir1-transforms*
1085 (remove-if-not #'cdr *delayed-ir1-transforms*))
1086 (let ((reoptimize nil))
1087 (dolist (assoc *delayed-ir1-transforms*)
1088 (let ((reasons (remove reason (cdr assoc))))
1089 (setf (cdr assoc) reasons)
1091 (let ((node (car assoc)))
1092 (unless (node-deleted node)
1094 (setf (node-reoptimize node) t)
1095 (let ((block (node-block node)))
1096 (setf (block-reoptimize block) t)
1097 (setf (component-reoptimize (block-component block)) t)))))))
1100 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1101 ;;; environment, and then install it as the function for the call
1102 ;;; NODE. We do local call analysis so that the new function is
1103 ;;; integrated into the control flow.
1105 ;;; We require the original function source name in order to generate
1106 ;;; a meaningful debug name for the lambda we set up. (It'd be
1107 ;;; possible to do this starting from debug names as well as source
1108 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1109 ;;; generality, since source names are always known to our callers.)
1110 (defun transform-call (node res source-name)
1111 (declare (type combination node) (list res))
1112 (aver (and (legal-fun-name-p source-name)
1113 (not (eql source-name '.anonymous.))))
1114 (with-ir1-environment-from-node node
1115 (let ((new-fun (ir1-convert-inline-lambda
1117 :debug-name (debug-namify "LAMBDA-inlined ~A"
1120 "<unknown function>"))))
1121 (ref (continuation-use (combination-fun node))))
1122 (change-ref-leaf ref new-fun)
1123 (setf (combination-kind node) :full)
1124 (locall-analyze-component *current-component*)))
1127 ;;; Replace a call to a foldable function of constant arguments with
1128 ;;; the result of evaluating the form. We insert the resulting
1129 ;;; constant node after the call, stealing the call's continuation. We
1130 ;;; give the call a continuation with no DEST, which should cause it
1131 ;;; and its arguments to go away. If there is an error during the
1132 ;;; evaluation, we give a warning and leave the call alone, making the
1133 ;;; call a :ERROR call.
1135 ;;; If there is more than one value, then we transform the call into a
1137 (defun constant-fold-call (call)
1138 (let ((args (mapcar #'continuation-value (combination-args call)))
1139 (fun-name (combination-fun-source-name call)))
1140 (multiple-value-bind (values win)
1141 (careful-call fun-name args call "constant folding")
1143 (setf (combination-kind call) :error)
1144 (let ((dummies (make-gensym-list (length args))))
1148 (declare (ignore ,@dummies))
1149 (values ,@(mapcar (lambda (x) `',x) values)))
1153 ;;;; local call optimization
1155 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1156 ;;; the leaf type is a function type, then just leave it alone, since
1157 ;;; TYPE is never going to be more specific than that (and
1158 ;;; TYPE-INTERSECTION would choke.)
1159 (defun propagate-to-refs (leaf type)
1160 (declare (type leaf leaf) (type ctype type))
1161 (let ((var-type (leaf-type leaf)))
1162 (unless (fun-type-p var-type)
1163 (let ((int (type-approx-intersection2 var-type type)))
1164 (when (type/= int var-type)
1165 (setf (leaf-type leaf) int)
1166 (dolist (ref (leaf-refs leaf))
1167 (derive-node-type ref int))))
1170 ;;; Figure out the type of a LET variable that has sets. We compute
1171 ;;; the union of the initial value Type and the types of all the set
1172 ;;; values and to a PROPAGATE-TO-REFS with this type.
1173 (defun propagate-from-sets (var type)
1174 (collect ((res type type-union))
1175 (dolist (set (basic-var-sets var))
1176 (res (continuation-type (set-value set)))
1177 (setf (node-reoptimize set) nil))
1178 (propagate-to-refs var (res)))
1181 ;;; If a LET variable, find the initial value's type and do
1182 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1184 (defun ir1-optimize-set (node)
1185 (declare (type cset node))
1186 (let ((var (set-var node)))
1187 (when (and (lambda-var-p var) (leaf-refs var))
1188 (let ((home (lambda-var-home var)))
1189 (when (eq (functional-kind home) :let)
1190 (let ((iv (let-var-initial-value var)))
1191 (setf (continuation-reoptimize iv) nil)
1192 (propagate-from-sets var (continuation-type iv)))))))
1194 (derive-node-type node (continuation-type (set-value node)))
1197 ;;; Return true if the value of Ref will always be the same (and is
1198 ;;; thus legal to substitute.)
1199 (defun constant-reference-p (ref)
1200 (declare (type ref ref))
1201 (let ((leaf (ref-leaf ref)))
1203 ((or constant functional) t)
1205 (null (lambda-var-sets leaf)))
1207 (not (eq (defined-fun-inlinep leaf) :notinline)))
1209 (case (global-var-kind leaf)
1210 (:global-function t))))))
1212 ;;; If we have a non-set LET var with a single use, then (if possible)
1213 ;;; replace the variable reference's CONT with the arg continuation.
1214 ;;; This is inhibited when:
1215 ;;; -- CONT has other uses, or
1216 ;;; -- CONT receives multiple values, or
1217 ;;; -- the reference is in a different environment from the variable, or
1218 ;;; -- either continuation has a funky TYPE-CHECK annotation.
1219 ;;; -- the continuations have incompatible assertions, so the new asserted type
1221 ;;; -- the var's DEST has a different policy than the ARG's (think safety).
1223 ;;; We change the REF to be a reference to NIL with unused value, and
1224 ;;; let it be flushed as dead code. A side effect of this substitution
1225 ;;; is to delete the variable.
1226 (defun substitute-single-use-continuation (arg var)
1227 (declare (type continuation arg) (type lambda-var var))
1228 (let* ((ref (first (leaf-refs var)))
1229 (cont (node-cont ref))
1230 (cont-atype (continuation-asserted-type cont))
1231 (dest (continuation-dest cont)))
1232 (when (and (eq (continuation-use cont) ref)
1234 (not (typep dest '(or creturn exit mv-combination)))
1235 (eq (node-home-lambda ref)
1236 (lambda-home (lambda-var-home var)))
1237 (member (continuation-type-check arg) '(t nil))
1238 (member (continuation-type-check cont) '(t nil))
1239 (not (eq (values-type-intersection
1241 (continuation-asserted-type arg))
1243 (eq (lexenv-policy (node-lexenv dest))
1244 (lexenv-policy (node-lexenv (continuation-dest arg)))))
1245 (aver (member (continuation-kind arg)
1246 '(:block-start :deleted-block-start :inside-block)))
1247 (assert-continuation-type arg cont-atype)
1248 (setf (node-derived-type ref) *wild-type*)
1249 (change-ref-leaf ref (find-constant nil))
1250 (substitute-continuation arg cont)
1251 (reoptimize-continuation arg)
1254 ;;; Delete a LET, removing the call and bind nodes, and warning about
1255 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1256 ;;; along right away and delete the REF and then the lambda, since we
1257 ;;; flush the FUN continuation.
1258 (defun delete-let (clambda)
1259 (declare (type clambda clambda))
1260 (aver (functional-letlike-p clambda))
1261 (note-unreferenced-vars clambda)
1262 (let ((call (let-combination clambda)))
1263 (flush-dest (basic-combination-fun call))
1265 (unlink-node (lambda-bind clambda))
1266 (setf (lambda-bind clambda) nil))
1269 ;;; This function is called when one of the arguments to a LET
1270 ;;; changes. We look at each changed argument. If the corresponding
1271 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1272 ;;; consider substituting for the variable, and also propagate
1273 ;;; derived-type information for the arg to all the VAR's refs.
1275 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1276 ;;; subtype of the argument's asserted type. This prevents type
1277 ;;; checking from being defeated, and also ensures that the best
1278 ;;; representation for the variable can be used.
1280 ;;; Substitution of individual references is inhibited if the
1281 ;;; reference is in a different component from the home. This can only
1282 ;;; happen with closures over top level lambda vars. In such cases,
1283 ;;; the references may have already been compiled, and thus can't be
1284 ;;; retroactively modified.
1286 ;;; If all of the variables are deleted (have no references) when we
1287 ;;; are done, then we delete the LET.
1289 ;;; Note that we are responsible for clearing the
1290 ;;; CONTINUATION-REOPTIMIZE flags.
1291 (defun propagate-let-args (call fun)
1292 (declare (type combination call) (type clambda fun))
1293 (loop for arg in (combination-args call)
1294 and var in (lambda-vars fun) do
1295 (when (and arg (continuation-reoptimize arg))
1296 (setf (continuation-reoptimize arg) nil)
1298 ((lambda-var-sets var)
1299 (propagate-from-sets var (continuation-type arg)))
1300 ((let ((use (continuation-use arg)))
1302 (let ((leaf (ref-leaf use)))
1303 (when (and (constant-reference-p use)
1304 (values-subtypep (leaf-type leaf)
1305 (continuation-asserted-type arg)))
1306 (propagate-to-refs var (continuation-type arg))
1307 (let ((use-component (node-component use)))
1310 (cond ((eq (node-component ref) use-component)
1313 (aver (lambda-toplevelish-p (lambda-home fun)))
1317 ((and (null (rest (leaf-refs var)))
1318 (substitute-single-use-continuation arg var)))
1320 (propagate-to-refs var (continuation-type arg))))))
1322 (when (every #'null (combination-args call))
1327 ;;; This function is called when one of the args to a non-LET local
1328 ;;; call changes. For each changed argument corresponding to an unset
1329 ;;; variable, we compute the union of the types across all calls and
1330 ;;; propagate this type information to the var's refs.
1332 ;;; If the function has an XEP, then we don't do anything, since we
1333 ;;; won't discover anything.
1335 ;;; We can clear the Continuation-Reoptimize flags for arguments in
1336 ;;; all calls corresponding to changed arguments in Call, since the
1337 ;;; only use in IR1 optimization of the Reoptimize flag for local call
1338 ;;; args is right here.
1339 (defun propagate-local-call-args (call fun)
1340 (declare (type combination call) (type clambda fun))
1342 (unless (or (functional-entry-fun fun)
1343 (lambda-optional-dispatch fun))
1344 (let* ((vars (lambda-vars fun))
1345 (union (mapcar (lambda (arg var)
1347 (continuation-reoptimize arg)
1348 (null (basic-var-sets var)))
1349 (continuation-type arg)))
1350 (basic-combination-args call)
1352 (this-ref (continuation-use (basic-combination-fun call))))
1354 (dolist (arg (basic-combination-args call))
1356 (setf (continuation-reoptimize arg) nil)))
1358 (dolist (ref (leaf-refs fun))
1359 (let ((dest (continuation-dest (node-cont ref))))
1360 (unless (or (eq ref this-ref) (not dest))
1362 (mapcar (lambda (this-arg old)
1364 (setf (continuation-reoptimize this-arg) nil)
1365 (type-union (continuation-type this-arg) old)))
1366 (basic-combination-args dest)
1369 (mapc (lambda (var type)
1371 (propagate-to-refs var type)))
1376 ;;;; multiple values optimization
1378 ;;; Do stuff to notice a change to a MV combination node. There are
1379 ;;; two main branches here:
1380 ;;; -- If the call is local, then it is already a MV let, or should
1381 ;;; become one. Note that although all :LOCAL MV calls must eventually
1382 ;;; be converted to :MV-LETs, there can be a window when the call
1383 ;;; is local, but has not been LET converted yet. This is because
1384 ;;; the entry-point lambdas may have stray references (in other
1385 ;;; entry points) that have not been deleted yet.
1386 ;;; -- The call is full. This case is somewhat similar to the non-MV
1387 ;;; combination optimization: we propagate return type information and
1388 ;;; notice non-returning calls. We also have an optimization
1389 ;;; which tries to convert MV-CALLs into MV-binds.
1390 (defun ir1-optimize-mv-combination (node)
1391 (ecase (basic-combination-kind node)
1393 (let ((fun-cont (basic-combination-fun node)))
1394 (when (continuation-reoptimize fun-cont)
1395 (setf (continuation-reoptimize fun-cont) nil)
1396 (maybe-let-convert (combination-lambda node))))
1397 (setf (continuation-reoptimize (first (basic-combination-args node))) nil)
1398 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1399 (unless (convert-mv-bind-to-let node)
1400 (ir1-optimize-mv-bind node))))
1402 (let* ((fun (basic-combination-fun node))
1403 (fun-changed (continuation-reoptimize fun))
1404 (args (basic-combination-args node)))
1406 (setf (continuation-reoptimize fun) nil)
1407 (let ((type (continuation-type fun)))
1408 (when (fun-type-p type)
1409 (derive-node-type node (fun-type-returns type))))
1410 (maybe-terminate-block node nil)
1411 (let ((use (continuation-use fun)))
1412 (when (and (ref-p use) (functional-p (ref-leaf use)))
1413 (convert-call-if-possible use node)
1414 (when (eq (basic-combination-kind node) :local)
1415 (maybe-let-convert (ref-leaf use))))))
1416 (unless (or (eq (basic-combination-kind node) :local)
1417 (eq (continuation-fun-name fun) '%throw))
1418 (ir1-optimize-mv-call node))
1420 (setf (continuation-reoptimize arg) nil))))
1424 ;;; Propagate derived type info from the values continuation to the
1426 (defun ir1-optimize-mv-bind (node)
1427 (declare (type mv-combination node))
1428 (let ((arg (first (basic-combination-args node)))
1429 (vars (lambda-vars (combination-lambda node))))
1430 (multiple-value-bind (types nvals)
1431 (values-types (continuation-derived-type arg))
1432 (unless (eq nvals :unknown)
1433 (mapc (lambda (var type)
1434 (if (basic-var-sets var)
1435 (propagate-from-sets var type)
1436 (propagate-to-refs var type)))
1439 (make-list (max (- (length vars) nvals) 0)
1440 :initial-element (specifier-type 'null))))))
1441 (setf (continuation-reoptimize arg) nil))
1444 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1446 ;;; -- The call has only one argument, and
1447 ;;; -- The function has a known fixed number of arguments, or
1448 ;;; -- The argument yields a known fixed number of values.
1450 ;;; What we do is change the function in the MV-CALL to be a lambda
1451 ;;; that "looks like an MV bind", which allows
1452 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1453 ;;; converted (the next time around.) This new lambda just calls the
1454 ;;; actual function with the MV-BIND variables as arguments. Note that
1455 ;;; this new MV bind is not let-converted immediately, as there are
1456 ;;; going to be stray references from the entry-point functions until
1457 ;;; they get deleted.
1459 ;;; In order to avoid loss of argument count checking, we only do the
1460 ;;; transformation according to a known number of expected argument if
1461 ;;; safety is unimportant. We can always convert if we know the number
1462 ;;; of actual values, since the normal call that we build will still
1463 ;;; do any appropriate argument count checking.
1465 ;;; We only attempt the transformation if the called function is a
1466 ;;; constant reference. This allows us to just splice the leaf into
1467 ;;; the new function, instead of trying to somehow bind the function
1468 ;;; expression. The leaf must be constant because we are evaluating it
1469 ;;; again in a different place. This also has the effect of squelching
1470 ;;; multiple warnings when there is an argument count error.
1471 (defun ir1-optimize-mv-call (node)
1472 (let ((fun (basic-combination-fun node))
1473 (*compiler-error-context* node)
1474 (ref (continuation-use (basic-combination-fun node)))
1475 (args (basic-combination-args node)))
1477 (unless (and (ref-p ref) (constant-reference-p ref)
1478 args (null (rest args)))
1479 (return-from ir1-optimize-mv-call))
1481 (multiple-value-bind (min max)
1482 (fun-type-nargs (continuation-type fun))
1484 (multiple-value-bind (types nvals)
1485 (values-types (continuation-derived-type (first args)))
1486 (declare (ignore types))
1487 (if (eq nvals :unknown) nil nvals))))
1490 (when (and min (< total-nvals min))
1492 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1495 (setf (basic-combination-kind node) :error)
1496 (return-from ir1-optimize-mv-call))
1497 (when (and max (> total-nvals max))
1499 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1502 (setf (basic-combination-kind node) :error)
1503 (return-from ir1-optimize-mv-call)))
1505 (let ((count (cond (total-nvals)
1506 ((and (policy node (zerop safety))
1511 (with-ir1-environment-from-node node
1512 (let* ((dums (make-gensym-list count))
1514 (fun (ir1-convert-lambda
1515 `(lambda (&optional ,@dums &rest ,ignore)
1516 (declare (ignore ,ignore))
1517 (funcall ,(ref-leaf ref) ,@dums)))))
1518 (change-ref-leaf ref fun)
1519 (aver (eq (basic-combination-kind node) :full))
1520 (locall-analyze-component *current-component*)
1521 (aver (eq (basic-combination-kind node) :local)))))))))
1525 ;;; (multiple-value-bind
1534 ;;; What we actually do is convert the VALUES combination into a
1535 ;;; normal LET combination calling the original :MV-LET lambda. If
1536 ;;; there are extra args to VALUES, discard the corresponding
1537 ;;; continuations. If there are insufficient args, insert references
1539 (defun convert-mv-bind-to-let (call)
1540 (declare (type mv-combination call))
1541 (let* ((arg (first (basic-combination-args call)))
1542 (use (continuation-use arg)))
1543 (when (and (combination-p use)
1544 (eq (continuation-fun-name (combination-fun use))
1546 (let* ((fun (combination-lambda call))
1547 (vars (lambda-vars fun))
1548 (vals (combination-args use))
1549 (nvars (length vars))
1550 (nvals (length vals)))
1551 (cond ((> nvals nvars)
1552 (mapc #'flush-dest (subseq vals nvars))
1553 (setq vals (subseq vals 0 nvars)))
1555 (with-ir1-environment-from-node use
1556 (let ((node-prev (node-prev use)))
1557 (setf (node-prev use) nil)
1558 (setf (continuation-next node-prev) nil)
1559 (collect ((res vals))
1560 (loop as cont = (make-continuation use)
1561 and prev = node-prev then cont
1562 repeat (- nvars nvals)
1563 do (reference-constant prev cont nil)
1566 (link-node-to-previous-continuation use
1567 (car (last vals)))))))
1568 (setf (combination-args use) vals)
1569 (flush-dest (combination-fun use))
1570 (let ((fun-cont (basic-combination-fun call)))
1571 (setf (continuation-dest fun-cont) use)
1572 (setf (combination-fun use) fun-cont))
1573 (setf (combination-kind use) :local)
1574 (setf (functional-kind fun) :let)
1575 (flush-dest (first (basic-combination-args call)))
1578 (reoptimize-continuation (first vals)))
1579 (propagate-to-args use fun))
1583 ;;; (values-list (list x y z))
1588 ;;; In implementation, this is somewhat similar to
1589 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1590 ;;; args of the VALUES-LIST call, flushing the old argument
1591 ;;; continuation (allowing the LIST to be flushed.)
1592 (defoptimizer (values-list optimizer) ((list) node)
1593 (let ((use (continuation-use list)))
1594 (when (and (combination-p use)
1595 (eq (continuation-fun-name (combination-fun use))
1597 (change-ref-leaf (continuation-use (combination-fun node))
1598 (find-free-fun 'values "in a strange place"))
1599 (setf (combination-kind node) :full)
1600 (let ((args (combination-args use)))
1602 (setf (continuation-dest arg) node))
1603 (setf (combination-args use) nil)
1605 (setf (combination-args node) args))
1608 ;;; If VALUES appears in a non-MV context, then effectively convert it
1609 ;;; to a PROG1. This allows the computation of the additional values
1610 ;;; to become dead code.
1611 (deftransform values ((&rest vals) * * :node node)
1612 (when (typep (continuation-dest (node-cont node))
1613 '(or creturn exit mv-combination))
1614 (give-up-ir1-transform))
1615 (setf (node-derived-type node) *wild-type*)
1617 (let ((dummies (make-gensym-list (length (cdr vals)))))
1618 `(lambda (val ,@dummies)
1619 (declare (ignore ,@dummies))