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 an LVAR whose sole use is a reference to a
23 (defun constant-lvar-p (thing)
25 (let ((use (principal-lvar-use thing)))
26 (and (ref-p use) (constant-p (ref-leaf use))))))
28 ;;; Return the constant value for an LVAR whose only use is a constant
30 (declaim (ftype (function (lvar) t) lvar-value))
31 (defun lvar-value (lvar)
32 (let ((use (principal-lvar-use lvar)))
33 (constant-value (ref-leaf use))))
35 ;;;; interface for obtaining results of type inference
37 ;;; Our best guess for the type of this lvar's value. Note that this
38 ;;; may be VALUES or FUNCTION type, which cannot be passed as an
39 ;;; argument to the normal type operations. See LVAR-TYPE.
41 ;;; The result value is cached in the LVAR-%DERIVED-TYPE slot. If the
42 ;;; slot is true, just return that value, otherwise recompute and
43 ;;; stash the value there.
44 #!-sb-fluid (declaim (inline lvar-derived-type))
45 (defun lvar-derived-type (lvar)
46 (declare (type lvar lvar))
47 (or (lvar-%derived-type lvar)
48 (setf (lvar-%derived-type lvar)
49 (%lvar-derived-type lvar))))
50 (defun %lvar-derived-type (lvar)
51 (declare (type lvar lvar))
52 (let ((uses (lvar-uses lvar)))
53 (cond ((null uses) *empty-type*)
55 (do ((res (node-derived-type (first uses))
56 (values-type-union (node-derived-type (first current))
58 (current (rest uses) (rest current)))
59 ((null current) res)))
61 (node-derived-type (lvar-uses lvar))))))
63 ;;; Return the derived type for LVAR's first value. This is guaranteed
64 ;;; not to be a VALUES or FUNCTION type.
65 (declaim (ftype (sfunction (lvar) ctype) lvar-type))
66 (defun lvar-type (lvar)
67 (single-value-type (lvar-derived-type lvar)))
69 ;;; If LVAR is an argument of a function, return a type which the
70 ;;; function checks LVAR for.
71 #!-sb-fluid (declaim (inline lvar-externally-checkable-type))
72 (defun lvar-externally-checkable-type (lvar)
73 (or (lvar-%externally-checkable-type lvar)
74 (%lvar-%externally-checkable-type lvar)))
75 (defun %lvar-%externally-checkable-type (lvar)
76 (declare (type lvar lvar))
77 (let ((dest (lvar-dest lvar)))
78 (if (not (and dest (combination-p dest)))
79 ;; TODO: MV-COMBINATION
80 (setf (lvar-%externally-checkable-type lvar) *wild-type*)
81 (let* ((fun (combination-fun dest))
82 (args (combination-args dest))
83 (fun-type (lvar-type fun)))
84 (setf (lvar-%externally-checkable-type fun) *wild-type*)
85 (if (or (not (call-full-like-p dest))
86 (not (fun-type-p fun-type))
87 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
88 (fun-type-wild-args fun-type))
91 (setf (lvar-%externally-checkable-type arg)
93 (map-combination-args-and-types
95 (setf (lvar-%externally-checkable-type arg)
96 (acond ((lvar-%externally-checkable-type arg)
97 (values-type-intersection
98 it (coerce-to-values type)))
99 (t (coerce-to-values type)))))
101 (lvar-%externally-checkable-type lvar))
102 #!-sb-fluid(declaim (inline flush-lvar-externally-checkable-type))
103 (defun flush-lvar-externally-checkable-type (lvar)
104 (declare (type lvar lvar))
105 (setf (lvar-%externally-checkable-type lvar) nil))
107 ;;;; interface routines used by optimizers
109 ;;; This function is called by optimizers to indicate that something
110 ;;; interesting has happened to the value of LVAR. Optimizers must
111 ;;; make sure that they don't call for reoptimization when nothing has
112 ;;; happened, since optimization will fail to terminate.
114 ;;; We clear any cached type for the lvar and set the reoptimize flags
115 ;;; on everything in sight.
116 (defun reoptimize-lvar (lvar)
117 (declare (type (or lvar null) lvar))
119 (setf (lvar-%derived-type lvar) nil)
120 (let ((dest (lvar-dest lvar)))
122 (setf (lvar-reoptimize lvar) t)
123 (setf (node-reoptimize dest) t)
124 (binding* (;; Since this may be called during IR1 conversion,
125 ;; PREV may be missing.
126 (prev (node-prev dest) :exit-if-null)
127 (block (ctran-block prev))
128 (component (block-component block)))
129 (when (typep dest 'cif)
130 (setf (block-test-modified block) t))
131 (setf (block-reoptimize block) t)
132 (setf (component-reoptimize component) t))))
134 (setf (block-type-check (node-block node)) t)))
137 (defun reoptimize-lvar-uses (lvar)
138 (declare (type lvar lvar))
140 (setf (node-reoptimize use) t)
141 (setf (block-reoptimize (node-block use)) t)
142 (setf (component-reoptimize (node-component use)) t)))
144 ;;; Annotate NODE to indicate that its result has been proven to be
145 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
146 ;;; only correct way to supply information discovered about a node's
147 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
148 ;;; information may be lost and reoptimization may not happen.
150 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
151 ;;; intersection is different from the old type, then we do a
152 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
153 (defun derive-node-type (node rtype)
154 (declare (type valued-node node) (type ctype rtype))
155 (let ((node-type (node-derived-type node)))
156 (unless (eq node-type rtype)
157 (let ((int (values-type-intersection node-type rtype))
158 (lvar (node-lvar node)))
159 (when (type/= node-type int)
160 (when (and *check-consistency*
161 (eq int *empty-type*)
162 (not (eq rtype *empty-type*)))
163 (let ((*compiler-error-context* node))
165 "New inferred type ~S conflicts with old type:~
166 ~% ~S~%*** possible internal error? Please report this."
167 (type-specifier rtype) (type-specifier node-type))))
168 (setf (node-derived-type node) int)
169 ;; If the new type consists of only one object, replace the
170 ;; node with a constant reference.
171 (when (and (ref-p node)
172 (lambda-var-p (ref-leaf node)))
173 (let ((type (single-value-type int)))
174 (when (and (member-type-p type)
175 (null (rest (member-type-members type))))
176 (change-ref-leaf node (find-constant
177 (first (member-type-members type)))))))
178 (reoptimize-lvar lvar)))))
181 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
182 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
183 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
184 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
185 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
186 (defun assert-lvar-type (lvar type policy)
187 (declare (type lvar lvar) (type ctype type))
188 (unless (values-subtypep (lvar-derived-type lvar) type)
189 (let* ((dest (lvar-dest lvar))
190 (ctran (node-prev dest)))
191 (with-ir1-environment-from-node dest
192 (let* ((cast (make-cast lvar type policy))
193 (internal-lvar (make-lvar))
194 (internal-ctran (make-ctran)))
195 (setf (ctran-next ctran) cast
196 (node-prev cast) ctran)
197 (use-continuation cast internal-ctran internal-lvar)
198 (link-node-to-previous-ctran dest internal-ctran)
199 (substitute-lvar internal-lvar lvar)
200 (setf (lvar-dest lvar) cast)
201 (reoptimize-lvar lvar)
202 (when (return-p dest)
203 (node-ends-block cast))
204 (setf (block-attributep (block-flags (node-block cast))
205 type-check type-asserted)
211 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
212 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
213 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
214 ;;; we are done, then another iteration would be beneficial.
215 (defun ir1-optimize (component)
216 (declare (type component component))
217 (setf (component-reoptimize component) nil)
218 (do-blocks (block component)
220 ;; We delete blocks when there is either no predecessor or the
221 ;; block is in a lambda that has been deleted. These blocks
222 ;; would eventually be deleted by DFO recomputation, but doing
223 ;; it here immediately makes the effect available to IR1
225 ((or (block-delete-p block)
226 (null (block-pred block)))
227 (delete-block block))
228 ((eq (functional-kind (block-home-lambda block)) :deleted)
229 ;; Preserve the BLOCK-SUCC invariant that almost every block has
230 ;; one successor (and a block with DELETE-P set is an acceptable
232 (mark-for-deletion block)
233 (delete-block block))
236 (let ((succ (block-succ block)))
237 (unless (singleton-p succ)
240 (let ((last (block-last block)))
243 (flush-dest (if-test last))
244 (when (unlink-node last)
247 (when (maybe-delete-exit last)
250 (unless (join-successor-if-possible block)
253 (when (and (block-reoptimize block) (block-component block))
254 (aver (not (block-delete-p block)))
255 (ir1-optimize-block block))
257 (cond ((and (block-delete-p block) (block-component block))
258 (delete-block block))
259 ((and (block-flush-p block) (block-component block))
260 (flush-dead-code block))))))
264 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
267 ;;; Note that although they are cleared here, REOPTIMIZE flags might
268 ;;; still be set upon return from this function, meaning that further
269 ;;; optimization is wanted (as a consequence of optimizations we did).
270 (defun ir1-optimize-block (block)
271 (declare (type cblock block))
272 ;; We clear the node and block REOPTIMIZE flags before doing the
273 ;; optimization, not after. This ensures that the node or block will
274 ;; be reoptimized if necessary.
275 (setf (block-reoptimize block) nil)
276 (do-nodes (node nil block :restart-p t)
277 (when (node-reoptimize node)
278 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
279 (setf (node-reoptimize node) nil)
283 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
284 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
285 ;; any argument changes.
286 (ir1-optimize-combination node))
288 (ir1-optimize-if node))
290 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
291 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
292 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
294 (setf (node-reoptimize node) t)
295 (ir1-optimize-return node))
297 (ir1-optimize-mv-combination node))
299 ;; With an EXIT, we derive the node's type from the VALUE's
301 (let ((value (exit-value node)))
303 (derive-node-type node (lvar-derived-type value)))))
305 (ir1-optimize-set node))
307 (ir1-optimize-cast node)))))
311 ;;; Try to join with a successor block. If we succeed, we return true,
313 (defun join-successor-if-possible (block)
314 (declare (type cblock block))
315 (let ((next (first (block-succ block))))
316 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
317 (cond ( ;; We cannot combine with a successor block if:
319 ;; The successor has more than one predecessor.
320 (rest (block-pred next))
321 ;; The successor is the current block (infinite loop).
323 ;; The next block has a different cleanup, and thus
324 ;; we may want to insert cleanup code between the
325 ;; two blocks at some point.
326 (not (eq (block-end-cleanup block)
327 (block-start-cleanup next)))
328 ;; The next block has a different home lambda, and
329 ;; thus the control transfer is a non-local exit.
330 (not (eq (block-home-lambda block)
331 (block-home-lambda next))))
334 (join-blocks block next)
337 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
338 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
339 ;;; for the two blocks so that any indicated optimization gets done.
340 (defun join-blocks (block1 block2)
341 (declare (type cblock block1 block2))
342 (let* ((last1 (block-last block1))
343 (last2 (block-last block2))
344 (succ (block-succ block2))
345 (start2 (block-start block2)))
346 (do ((ctran start2 (node-next (ctran-next ctran))))
348 (setf (ctran-block ctran) block1))
350 (unlink-blocks block1 block2)
352 (unlink-blocks block2 block)
353 (link-blocks block1 block))
355 (setf (ctran-kind start2) :inside-block)
356 (setf (node-next last1) start2)
357 (setf (ctran-use start2) last1)
358 (setf (block-last block1) last2))
360 (setf (block-flags block1)
361 (attributes-union (block-flags block1)
363 (block-attributes type-asserted test-modified)))
365 (let ((next (block-next block2))
366 (prev (block-prev block2)))
367 (setf (block-next prev) next)
368 (setf (block-prev next) prev))
372 ;;; Delete any nodes in BLOCK whose value is unused and which have no
373 ;;; side effects. We can delete sets of lexical variables when the set
374 ;;; variable has no references.
375 (defun flush-dead-code (block)
376 (declare (type cblock block))
377 (setf (block-flush-p block) nil)
378 (do-nodes-backwards (node lvar block)
385 (let ((info (combination-kind node)))
386 (when (fun-info-p info)
387 (let ((attr (fun-info-attributes info)))
388 (when (and (not (ir1-attributep attr call))
389 ;; ### For now, don't delete potentially
390 ;; flushable calls when they have the CALL
391 ;; attribute. Someday we should look at the
392 ;; functional args to determine if they have
394 (if (policy node (= safety 3))
395 (ir1-attributep attr flushable)
396 (ir1-attributep attr unsafely-flushable)))
397 (flush-combination node))))))
399 (when (eq (basic-combination-kind node) :local)
400 (let ((fun (combination-lambda node)))
401 (when (dolist (var (lambda-vars fun) t)
402 (when (or (leaf-refs var)
403 (lambda-var-sets var))
405 (flush-dest (first (basic-combination-args node)))
408 (let ((value (exit-value node)))
411 (setf (exit-value node) nil))))
413 (let ((var (set-var node)))
414 (when (and (lambda-var-p var)
415 (null (leaf-refs var)))
416 (flush-dest (set-value node))
417 (setf (basic-var-sets var)
418 (delq node (basic-var-sets var)))
419 (unlink-node node))))
421 (unless (cast-type-check node)
422 (flush-dest (cast-value node))
423 (unlink-node node))))))
427 ;;;; local call return type propagation
429 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
430 ;;; flag set. It iterates over the uses of the RESULT, looking for
431 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
432 ;;; call, then we union its type together with the types of other such
433 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
434 ;;; type with the RESULT's asserted type. We can make this
435 ;;; intersection now (potentially before type checking) because this
436 ;;; assertion on the result will eventually be checked (if
439 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
440 ;;; combination, which may change the succesor of the call to be the
441 ;;; called function, and if so, checks if the call can become an
442 ;;; assignment. If we convert to an assignment, we abort, since the
443 ;;; RETURN has been deleted.
444 (defun find-result-type (node)
445 (declare (type creturn node))
446 (let ((result (return-result node)))
447 (collect ((use-union *empty-type* values-type-union))
448 (do-uses (use result)
449 (cond ((and (basic-combination-p use)
450 (eq (basic-combination-kind use) :local))
451 (aver (eq (lambda-tail-set (node-home-lambda use))
452 (lambda-tail-set (combination-lambda use))))
453 (when (combination-p use)
454 (when (nth-value 1 (maybe-convert-tail-local-call use))
455 (return-from find-result-type (values)))))
457 (use-union (node-derived-type use)))))
459 ;; (values-type-intersection
460 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
464 (setf (return-result-type node) int))))
467 ;;; Do stuff to realize that something has changed about the value
468 ;;; delivered to a return node. Since we consider the return values of
469 ;;; all functions in the tail set to be equivalent, this amounts to
470 ;;; bringing the entire tail set up to date. We iterate over the
471 ;;; returns for all the functions in the tail set, reanalyzing them
472 ;;; all (not treating NODE specially.)
474 ;;; When we are done, we check whether the new type is different from
475 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
476 ;;; all the lvars for references to functions in the tail set. This
477 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
478 ;;; results of the calls.
479 (defun ir1-optimize-return (node)
480 (declare (type creturn node))
481 (let* ((tails (lambda-tail-set (return-lambda node)))
482 (funs (tail-set-funs tails)))
483 (collect ((res *empty-type* values-type-union))
485 (let ((return (lambda-return fun)))
487 (when (node-reoptimize return)
488 (setf (node-reoptimize return) nil)
489 (find-result-type return))
490 (res (return-result-type return)))))
492 (when (type/= (res) (tail-set-type tails))
493 (setf (tail-set-type tails) (res))
494 (dolist (fun (tail-set-funs tails))
495 (dolist (ref (leaf-refs fun))
496 (reoptimize-lvar (node-lvar ref)))))))
502 ;;; If the test has multiple uses, replicate the node when possible.
503 ;;; Also check whether the predicate is known to be true or false,
504 ;;; deleting the IF node in favor of the appropriate branch when this
506 (defun ir1-optimize-if (node)
507 (declare (type cif node))
508 (let ((test (if-test node))
509 (block (node-block node)))
511 (when (and (eq (block-start-node block) node)
512 (listp (lvar-uses test)))
514 (when (immediately-used-p test use)
515 (convert-if-if use node)
516 (when (not (listp (lvar-uses test))) (return)))))
518 (let* ((type (lvar-type test))
520 (cond ((constant-lvar-p test)
521 (if (lvar-value test)
522 (if-alternative node)
523 (if-consequent node)))
524 ((not (types-equal-or-intersect type (specifier-type 'null)))
525 (if-alternative node))
526 ((type= type (specifier-type 'null))
527 (if-consequent node)))))
530 (when (rest (block-succ block))
531 (unlink-blocks block victim))
532 (setf (component-reanalyze (node-component node)) t)
533 (unlink-node node))))
536 ;;; Create a new copy of an IF node that tests the value of the node
537 ;;; USE. The test must have >1 use, and must be immediately used by
538 ;;; USE. NODE must be the only node in its block (implying that
539 ;;; block-start = if-test).
541 ;;; This optimization has an effect semantically similar to the
542 ;;; source-to-source transformation:
543 ;;; (IF (IF A B C) D E) ==>
544 ;;; (IF A (IF B D E) (IF C D E))
546 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
547 ;;; node so that dead code deletion notes will definitely not consider
548 ;;; either node to be part of the original source. One node might
549 ;;; become unreachable, resulting in a spurious note.
550 (defun convert-if-if (use node)
551 (declare (type node use) (type cif node))
552 (with-ir1-environment-from-node node
553 (let* ((block (node-block node))
554 (test (if-test node))
555 (cblock (if-consequent node))
556 (ablock (if-alternative node))
557 (use-block (node-block use))
558 (new-ctran (make-ctran))
559 (new-lvar (make-lvar))
560 (new-node (make-if :test new-lvar
562 :alternative ablock))
563 (new-block (ctran-starts-block new-ctran)))
564 (link-node-to-previous-ctran new-node new-ctran)
565 (setf (lvar-dest new-lvar) new-node)
566 (setf (block-last new-block) new-node)
568 (unlink-blocks use-block block)
569 (%delete-lvar-use use)
570 (add-lvar-use use new-lvar)
571 (link-blocks use-block new-block)
573 (link-blocks new-block cblock)
574 (link-blocks new-block ablock)
576 (push "<IF Duplication>" (node-source-path node))
577 (push "<IF Duplication>" (node-source-path new-node))
579 (reoptimize-lvar test)
580 (reoptimize-lvar new-lvar)
581 (setf (component-reanalyze *current-component*) t)))
584 ;;;; exit IR1 optimization
586 ;;; This function attempts to delete an exit node, returning true if
587 ;;; it deletes the block as a consequence:
588 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
589 ;;; anything, since there is nothing to be done.
590 ;;; -- If the exit node and its ENTRY have the same home lambda then
591 ;;; we know the exit is local, and can delete the exit. We change
592 ;;; uses of the Exit-Value to be uses of the original lvar,
593 ;;; then unlink the node. If the exit is to a TR context, then we
594 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
595 ;;; their value to this exit.
596 ;;; -- If there is no value (as in a GO), then we skip the value
599 ;;; This function is also called by environment analysis, since it
600 ;;; wants all exits to be optimized even if normal optimization was
602 (defun maybe-delete-exit (node)
603 (declare (type exit node))
604 (let ((value (exit-value node))
605 (entry (exit-entry node)))
607 (eq (node-home-lambda node) (node-home-lambda entry)))
608 (setf (entry-exits entry) (delq node (entry-exits entry)))
610 (delete-filter node (node-lvar node) value)
611 (unlink-node node)))))
614 ;;;; combination IR1 optimization
616 ;;; Report as we try each transform?
618 (defvar *show-transforms-p* nil)
620 ;;; Do IR1 optimizations on a COMBINATION node.
621 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
622 (defun ir1-optimize-combination (node)
623 (when (lvar-reoptimize (basic-combination-fun node))
624 (propagate-fun-change node))
625 (let ((args (basic-combination-args node))
626 (kind (basic-combination-kind node)))
629 (let ((fun (combination-lambda node)))
630 (if (eq (functional-kind fun) :let)
631 (propagate-let-args node fun)
632 (propagate-local-call-args node fun))))
636 (setf (lvar-reoptimize arg) nil))))
640 (setf (lvar-reoptimize arg) nil)))
642 (let ((attr (fun-info-attributes kind)))
643 (when (and (ir1-attributep attr foldable)
644 ;; KLUDGE: The next test could be made more sensitive,
645 ;; only suppressing constant-folding of functions with
646 ;; CALL attributes when they're actually passed
647 ;; function arguments. -- WHN 19990918
648 (not (ir1-attributep attr call))
649 (every #'constant-lvar-p args)
651 ;; Even if the function is foldable in principle,
652 ;; it might be one of our low-level
653 ;; implementation-specific functions. Such
654 ;; functions don't necessarily exist at runtime on
655 ;; a plain vanilla ANSI Common Lisp
656 ;; cross-compilation host, in which case the
657 ;; cross-compiler can't fold it because the
658 ;; cross-compiler doesn't know how to evaluate it.
660 (or (fboundp (combination-fun-source-name node))
661 (progn (format t ";;; !!! Unbound fun: (~S~{ ~S~})~%"
662 (combination-fun-source-name node)
663 (mapcar #'lvar-value args))
665 (constant-fold-call node)
666 (return-from ir1-optimize-combination)))
668 (let ((fun (fun-info-derive-type kind)))
670 (let ((res (funcall fun node)))
672 (derive-node-type node (coerce-to-values res))
673 (maybe-terminate-block node nil)))))
675 (let ((fun (fun-info-optimizer kind)))
676 (unless (and fun (funcall fun node))
677 (dolist (x (fun-info-transforms kind))
679 (when *show-transforms-p*
680 (let* ((lvar (basic-combination-fun node))
681 (fname (lvar-fun-name lvar t)))
682 (/show "trying transform" x (transform-function x) "for" fname)))
683 (unless (ir1-transform node x)
685 (when *show-transforms-p*
686 (/show "quitting because IR1-TRANSFORM result was NIL"))
691 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
692 ;;; the block there, and link it to the component tail.
694 ;;; Except when called during IR1 convertion, we delete the
695 ;;; continuation if it has no other uses. (If it does have other uses,
698 ;;; Termination on the basis of a continuation type is
700 ;;; -- The continuation is deleted (hence the assertion is spurious), or
701 ;;; -- We are in IR1 conversion (where THE assertions are subject to
702 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
703 ;;; uses can(?) be added later. -- APD, 2003-07-17
705 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
706 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
707 (declare (type (or basic-combination cast) node))
708 (let* ((block (node-block node))
709 (lvar (node-lvar node))
710 (ctran (node-next node))
711 (tail (component-tail (block-component block)))
712 (succ (first (block-succ block))))
713 (unless (or (and (eq node (block-last block)) (eq succ tail))
714 (block-delete-p block))
715 (when (eq (node-derived-type node) *empty-type*)
716 (cond (ir1-converting-not-optimizing-p
719 (aver (eq (block-last block) node)))
721 (setf (block-last block) node)
722 (setf (ctran-use ctran) nil)
723 (setf (ctran-kind ctran) :unused)
724 (setf (ctran-block ctran) nil)
725 (setf (node-next node) nil)
726 (link-blocks block (ctran-starts-block ctran)))))
728 (node-ends-block node)))
730 (unlink-blocks block (first (block-succ block)))
731 (setf (component-reanalyze (block-component block)) t)
732 (aver (not (block-succ block)))
733 (link-blocks block tail)
734 (if ir1-converting-not-optimizing-p
735 (%delete-lvar-use node)
736 (delete-lvar-use node))
739 ;;; This is called both by IR1 conversion and IR1 optimization when
740 ;;; they have verified the type signature for the call, and are
741 ;;; wondering if something should be done to special-case the call. If
742 ;;; CALL is a call to a global function, then see whether it defined
744 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
745 ;;; the expansion and change the call to call it. Expansion is
746 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
747 ;;; true, we never expand, since this function has already been
748 ;;; converted. Local call analysis will duplicate the definition
749 ;;; if necessary. We claim that the parent form is LABELS for
750 ;;; context declarations, since we don't want it to be considered
751 ;;; a real global function.
752 ;;; -- If it is a known function, mark it as such by setting the KIND.
754 ;;; We return the leaf referenced (NIL if not a leaf) and the
755 ;;; FUN-INFO assigned.
756 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
757 (declare (type combination call))
758 (let* ((ref (lvar-uses (basic-combination-fun call)))
759 (leaf (when (ref-p ref) (ref-leaf ref)))
760 (inlinep (if (defined-fun-p leaf)
761 (defined-fun-inlinep leaf)
764 ((eq inlinep :notinline) (values nil nil))
765 ((not (and (global-var-p leaf)
766 (eq (global-var-kind leaf) :global-function)))
771 ((nil :maybe-inline) (policy call (zerop space))))
773 (defined-fun-inline-expansion leaf)
774 (let ((fun (defined-fun-functional leaf)))
776 (and (eq inlinep :inline) (functional-kind fun))))
777 (inline-expansion-ok call))
778 (flet (;; FIXME: Is this what the old CMU CL internal documentation
779 ;; called semi-inlining? A more descriptive name would
780 ;; be nice. -- WHN 2002-01-07
782 (let ((res (ir1-convert-lambda-for-defun
783 (defined-fun-inline-expansion leaf)
785 #'ir1-convert-inline-lambda)))
786 (setf (defined-fun-functional leaf) res)
787 (change-ref-leaf ref res))))
788 (if ir1-converting-not-optimizing-p
790 (with-ir1-environment-from-node call
792 (locall-analyze-component *current-component*))))
794 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
797 (let ((info (info :function :info (leaf-source-name leaf))))
799 (values leaf (setf (basic-combination-kind call) info))
800 (values leaf nil)))))))
802 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
803 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
804 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
805 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
806 ;;; syntax check, arg/result type processing, but still call
807 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
808 ;;; and that checking is done by local call analysis.
809 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
810 (declare (type combination call) (type ctype type))
811 (cond ((not (fun-type-p type))
812 (aver (multiple-value-bind (val win)
813 (csubtypep type (specifier-type 'function))
815 (recognize-known-call call ir1-converting-not-optimizing-p))
816 ((valid-fun-use call type
817 :argument-test #'always-subtypep
818 :result-test #'always-subtypep
819 ;; KLUDGE: Common Lisp is such a dynamic
820 ;; language that all we can do here in
821 ;; general is issue a STYLE-WARNING. It
822 ;; would be nice to issue a full WARNING
823 ;; in the special case of of type
824 ;; mismatches within a compilation unit
825 ;; (as in section 3.2.2.3 of the spec)
826 ;; but at least as of sbcl-0.6.11, we
827 ;; don't keep track of whether the
828 ;; mismatched data came from the same
829 ;; compilation unit, so we can't do that.
832 ;; FIXME: Actually, I think we could
833 ;; issue a full WARNING if the call
834 ;; violates a DECLAIM FTYPE.
835 :lossage-fun #'compiler-style-warn
836 :unwinnage-fun #'compiler-notify)
837 (assert-call-type call type)
838 (maybe-terminate-block call ir1-converting-not-optimizing-p)
839 (recognize-known-call call ir1-converting-not-optimizing-p))
841 (setf (combination-kind call) :error)
844 ;;; This is called by IR1-OPTIMIZE when the function for a call has
845 ;;; changed. If the call is local, we try to LET-convert it, and
846 ;;; derive the result type. If it is a :FULL call, we validate it
847 ;;; against the type, which recognizes known calls, does inline
848 ;;; expansion, etc. If a call to a predicate in a non-conditional
849 ;;; position or to a function with a source transform, then we
850 ;;; reconvert the form to give IR1 another chance.
851 (defun propagate-fun-change (call)
852 (declare (type combination call))
853 (let ((*compiler-error-context* call)
854 (fun-lvar (basic-combination-fun call)))
855 (setf (lvar-reoptimize fun-lvar) nil)
856 (case (combination-kind call)
858 (let ((fun (combination-lambda call)))
859 (maybe-let-convert fun)
860 (unless (member (functional-kind fun) '(:let :assignment :deleted))
861 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
863 (multiple-value-bind (leaf info)
864 (validate-call-type call (lvar-type fun-lvar) nil)
865 (cond ((functional-p leaf)
866 (convert-call-if-possible
867 (lvar-uses (basic-combination-fun call))
870 ((and (leaf-has-source-name-p leaf)
871 (or (info :function :source-transform (leaf-source-name leaf))
873 (ir1-attributep (fun-info-attributes info)
875 (let ((lvar (node-lvar call)))
876 (and lvar (not (if-p (lvar-dest lvar))))))))
877 (let ((name (leaf-source-name leaf))
878 (dummies (make-gensym-list
879 (length (combination-args call)))))
882 (,@(if (symbolp name)
886 (leaf-source-name leaf)))))))))
889 ;;;; known function optimization
891 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
892 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
893 ;;; replace it, otherwise add a new one.
894 (defun record-optimization-failure (node transform args)
895 (declare (type combination node) (type transform transform)
896 (type (or fun-type list) args))
897 (let* ((table (component-failed-optimizations *component-being-compiled*))
898 (found (assoc transform (gethash node table))))
900 (setf (cdr found) args)
901 (push (cons transform args) (gethash node table))))
904 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
905 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
906 ;;; doing the transform for some reason and FLAME is true, then we
907 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
908 ;;; finalize to pick up. We return true if the transform failed, and
909 ;;; thus further transformation should be attempted. We return false
910 ;;; if either the transform succeeded or was aborted.
911 (defun ir1-transform (node transform)
912 (declare (type combination node) (type transform transform))
913 (let* ((type (transform-type transform))
914 (fun (transform-function transform))
915 (constrained (fun-type-p type))
916 (table (component-failed-optimizations *component-being-compiled*))
917 (flame (if (transform-important transform)
918 (policy node (>= speed inhibit-warnings))
919 (policy node (> speed inhibit-warnings))))
920 (*compiler-error-context* node))
921 (cond ((or (not constrained)
922 (valid-fun-use node type))
923 (multiple-value-bind (severity args)
924 (catch 'give-up-ir1-transform
927 (combination-fun-source-name node))
934 (setf (combination-kind node) :error)
936 (apply #'compiler-warn args))
942 (record-optimization-failure node transform args))
943 (setf (gethash node table)
944 (remove transform (gethash node table) :key #'car)))
952 :argument-test #'types-equal-or-intersect
953 :result-test #'values-types-equal-or-intersect))
954 (record-optimization-failure node transform type)
959 ;;; When we don't like an IR1 transform, we throw the severity/reason
962 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
963 ;;; aborting this attempt to transform the call, but admitting the
964 ;;; possibility that this or some other transform will later succeed.
965 ;;; If arguments are supplied, they are format arguments for an
968 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
969 ;;; force a normal call to the function at run time. No further
970 ;;; optimizations will be attempted.
972 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
973 ;;; delay the transform on the node until later. REASONS specifies
974 ;;; when the transform will be later retried. The :OPTIMIZE reason
975 ;;; causes the transform to be delayed until after the current IR1
976 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
977 ;;; be delayed until after constraint propagation.
979 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
980 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
981 ;;; do CASE operations on the various REASON values, it might be a
982 ;;; good idea to go OO, representing the reasons by objects, using
983 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
984 ;;; SIGNAL instead of THROW.
985 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
986 (defun give-up-ir1-transform (&rest args)
987 (throw 'give-up-ir1-transform (values :failure args)))
988 (defun abort-ir1-transform (&rest args)
989 (throw 'give-up-ir1-transform (values :aborted args)))
990 (defun delay-ir1-transform (node &rest reasons)
991 (let ((assoc (assoc node *delayed-ir1-transforms*)))
993 (setf *delayed-ir1-transforms*
994 (acons node reasons *delayed-ir1-transforms*))
995 (throw 'give-up-ir1-transform :delayed))
997 (dolist (reason reasons)
998 (pushnew reason (cdr assoc)))
999 (throw 'give-up-ir1-transform :delayed)))))
1001 ;;; Clear any delayed transform with no reasons - these should have
1002 ;;; been tried in the last pass. Then remove the reason from the
1003 ;;; delayed transform reasons, and if any become empty then set
1004 ;;; reoptimize flags for the node. Return true if any transforms are
1006 (defun retry-delayed-ir1-transforms (reason)
1007 (setf *delayed-ir1-transforms*
1008 (remove-if-not #'cdr *delayed-ir1-transforms*))
1009 (let ((reoptimize nil))
1010 (dolist (assoc *delayed-ir1-transforms*)
1011 (let ((reasons (remove reason (cdr assoc))))
1012 (setf (cdr assoc) reasons)
1014 (let ((node (car assoc)))
1015 (unless (node-deleted node)
1017 (setf (node-reoptimize node) t)
1018 (let ((block (node-block node)))
1019 (setf (block-reoptimize block) t)
1020 (setf (component-reoptimize (block-component block)) t)))))))
1023 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1024 ;;; environment, and then install it as the function for the call
1025 ;;; NODE. We do local call analysis so that the new function is
1026 ;;; integrated into the control flow.
1028 ;;; We require the original function source name in order to generate
1029 ;;; a meaningful debug name for the lambda we set up. (It'd be
1030 ;;; possible to do this starting from debug names as well as source
1031 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1032 ;;; generality, since source names are always known to our callers.)
1033 (defun transform-call (call res source-name)
1034 (declare (type combination call) (list res))
1035 (aver (and (legal-fun-name-p source-name)
1036 (not (eql source-name '.anonymous.))))
1037 (node-ends-block call)
1038 (with-ir1-environment-from-node call
1039 (with-component-last-block (*current-component*
1040 (block-next (node-block call)))
1041 (let ((new-fun (ir1-convert-inline-lambda
1043 :debug-name (debug-namify "LAMBDA-inlined ~A"
1046 "<unknown function>"))))
1047 (ref (lvar-use (combination-fun call))))
1048 (change-ref-leaf ref new-fun)
1049 (setf (combination-kind call) :full)
1050 (locall-analyze-component *current-component*))))
1053 ;;; Replace a call to a foldable function of constant arguments with
1054 ;;; the result of evaluating the form. If there is an error during the
1055 ;;; evaluation, we give a warning and leave the call alone, making the
1056 ;;; call a :ERROR call.
1058 ;;; If there is more than one value, then we transform the call into a
1060 (defun constant-fold-call (call)
1061 (let ((args (mapcar #'lvar-value (combination-args call)))
1062 (fun-name (combination-fun-source-name call)))
1063 (multiple-value-bind (values win)
1064 (careful-call fun-name
1067 ;; Note: CMU CL had COMPILER-WARN here, and that
1068 ;; seems more natural, but it's probably not.
1070 ;; It's especially not while bug 173 exists:
1073 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1075 ;; can cause constant-folding TYPE-ERRORs (in
1076 ;; #'<=) when END can be proved to be NIL, even
1077 ;; though the code is perfectly legal and safe
1078 ;; because a NIL value of END means that the
1079 ;; #'<= will never be executed.
1081 ;; Moreover, even without bug 173,
1082 ;; quite-possibly-valid code like
1083 ;; (COND ((NONINLINED-PREDICATE END)
1084 ;; (UNLESS (<= END SIZE))
1086 ;; (where NONINLINED-PREDICATE is something the
1087 ;; compiler can't do at compile time, but which
1088 ;; turns out to make the #'<= expression
1089 ;; unreachable when END=NIL) could cause errors
1090 ;; when the compiler tries to constant-fold (<=
1093 ;; So, with or without bug 173, it'd be
1094 ;; unnecessarily evil to do a full
1095 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1096 ;; from COMPILE-FILE) for legal code, so we we
1097 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1098 #'compiler-style-warn
1101 (setf (combination-kind call) :error))
1102 ((and (proper-list-of-length-p values 1))
1103 (with-ir1-environment-from-node call
1104 (let* ((lvar (node-lvar call))
1105 (prev (node-prev call))
1106 (intermediate-ctran (make-ctran)))
1107 (%delete-lvar-use call)
1108 (setf (ctran-next prev) nil)
1109 (setf (node-prev call) nil)
1110 (reference-constant prev intermediate-ctran lvar
1112 (link-node-to-previous-ctran call intermediate-ctran)
1113 (reoptimize-lvar lvar)
1114 (flush-combination call))))
1115 (t (let ((dummies (make-gensym-list (length args))))
1119 (declare (ignore ,@dummies))
1120 (values ,@(mapcar (lambda (x) `',x) values)))
1124 ;;;; local call optimization
1126 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1127 ;;; the leaf type is a function type, then just leave it alone, since
1128 ;;; TYPE is never going to be more specific than that (and
1129 ;;; TYPE-INTERSECTION would choke.)
1130 (defun propagate-to-refs (leaf type)
1131 (declare (type leaf leaf) (type ctype type))
1132 (let ((var-type (leaf-type leaf)))
1133 (unless (fun-type-p var-type)
1134 (let ((int (type-approx-intersection2 var-type type)))
1135 (when (type/= int var-type)
1136 (setf (leaf-type leaf) int)
1137 (dolist (ref (leaf-refs leaf))
1138 (derive-node-type ref (make-single-value-type int))
1139 ;; KLUDGE: LET var substitution
1140 (let* ((lvar (node-lvar ref)))
1141 (when (and lvar (combination-p (lvar-dest lvar)))
1142 (reoptimize-lvar lvar))))))
1145 ;;; Iteration variable: exactly one SETQ of the form:
1147 ;;; (let ((var initial))
1149 ;;; (setq var (+ var step))
1151 (defun maybe-infer-iteration-var-type (var initial-type)
1152 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1154 (() (null (rest sets)) :exit-if-null)
1155 (set-use (principal-lvar-use (set-value set)))
1156 (() (and (combination-p set-use)
1157 (fun-info-p (combination-kind set-use))
1158 (eq (combination-fun-source-name set-use) '+))
1160 (+-args (basic-combination-args set-use))
1161 (() (and (proper-list-of-length-p +-args 2 2)
1162 (let ((first (principal-lvar-use
1165 (eq (ref-leaf first) var))))
1167 (step-type (lvar-type (second +-args)))
1168 (set-type (lvar-type (set-value set))))
1169 (when (and (numeric-type-p initial-type)
1170 (numeric-type-p step-type)
1171 (numeric-type-equal initial-type step-type))
1172 (multiple-value-bind (low high)
1173 (cond ((csubtypep step-type (specifier-type '(real 0 *)))
1174 (values (numeric-type-low initial-type)
1175 (when (and (numeric-type-p set-type)
1176 (numeric-type-equal set-type initial-type))
1177 (numeric-type-high set-type))))
1178 ((csubtypep step-type (specifier-type '(real * 0)))
1179 (values (when (and (numeric-type-p set-type)
1180 (numeric-type-equal set-type initial-type))
1181 (numeric-type-low set-type))
1182 (numeric-type-high initial-type)))
1185 (modified-numeric-type initial-type
1188 :enumerable nil)))))
1189 (deftransform + ((x y) * * :result result)
1190 "check for iteration variable reoptimization"
1191 (let ((dest (principal-lvar-end result))
1192 (use (principal-lvar-use x)))
1193 (when (and (ref-p use)
1197 (reoptimize-lvar (set-value dest))))
1198 (give-up-ir1-transform))
1200 ;;; Figure out the type of a LET variable that has sets. We compute
1201 ;;; the union of the INITIAL-TYPE and the types of all the set
1202 ;;; values and to a PROPAGATE-TO-REFS with this type.
1203 (defun propagate-from-sets (var initial-type)
1204 (collect ((res initial-type type-union))
1205 (dolist (set (basic-var-sets var))
1206 (let ((type (lvar-type (set-value set))))
1208 (when (node-reoptimize set)
1209 (derive-node-type set (make-single-value-type type))
1210 (setf (node-reoptimize set) nil))))
1212 (awhen (maybe-infer-iteration-var-type var initial-type)
1214 (propagate-to-refs var res)))
1217 ;;; If a LET variable, find the initial value's type and do
1218 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1220 (defun ir1-optimize-set (node)
1221 (declare (type cset node))
1222 (let ((var (set-var node)))
1223 (when (and (lambda-var-p var) (leaf-refs var))
1224 (let ((home (lambda-var-home var)))
1225 (when (eq (functional-kind home) :let)
1226 (let* ((initial-value (let-var-initial-value var))
1227 (initial-type (lvar-type initial-value)))
1228 (setf (lvar-reoptimize initial-value) nil)
1229 (propagate-from-sets var initial-type))))))
1231 (derive-node-type node (make-single-value-type
1232 (lvar-type (set-value node))))
1235 ;;; Return true if the value of REF will always be the same (and is
1236 ;;; thus legal to substitute.)
1237 (defun constant-reference-p (ref)
1238 (declare (type ref ref))
1239 (let ((leaf (ref-leaf ref)))
1241 ((or constant functional) t)
1243 (null (lambda-var-sets leaf)))
1245 (not (eq (defined-fun-inlinep leaf) :notinline)))
1247 (case (global-var-kind leaf)
1249 (let ((name (leaf-source-name leaf)))
1251 (eq (symbol-package (fun-name-block-name name))
1253 (info :function :info name)))))))))
1255 ;;; If we have a non-set LET var with a single use, then (if possible)
1256 ;;; replace the variable reference's LVAR with the arg lvar.
1258 ;;; We change the REF to be a reference to NIL with unused value, and
1259 ;;; let it be flushed as dead code. A side effect of this substitution
1260 ;;; is to delete the variable.
1261 (defun substitute-single-use-lvar (arg var)
1262 (declare (type lvar arg) (type lambda-var var))
1263 (binding* ((ref (first (leaf-refs var)))
1264 (lvar (node-lvar ref) :exit-if-null)
1265 (dest (lvar-dest lvar)))
1267 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1268 ;; LVAR-USEs should not be met on one path.
1269 (eq (lvar-uses lvar) ref)
1271 ;; we should not change lifetime of unknown values lvars
1273 (and (type-single-value-p (lvar-derived-type arg))
1274 (multiple-value-bind (pdest pprev)
1275 (principal-lvar-end lvar)
1276 (declare (ignore pdest))
1277 (lvar-single-value-p pprev))))
1279 (or (eq (basic-combination-fun dest) lvar)
1280 (and (eq (basic-combination-kind dest) :local)
1281 (type-single-value-p (lvar-derived-type arg)))))
1283 ;; While CRETURN and EXIT nodes may be known-values,
1284 ;; they have their own complications, such as
1285 ;; substitution into CRETURN may create new tail calls.
1288 (aver (lvar-single-value-p lvar))
1290 (eq (node-home-lambda ref)
1291 (lambda-home (lambda-var-home var))))
1292 (setf (node-derived-type ref) *wild-type*)
1293 (substitute-lvar-uses lvar arg)
1294 (delete-lvar-use ref)
1295 (change-ref-leaf ref (find-constant nil))
1298 (reoptimize-lvar lvar)
1301 ;;; Delete a LET, removing the call and bind nodes, and warning about
1302 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1303 ;;; along right away and delete the REF and then the lambda, since we
1304 ;;; flush the FUN lvar.
1305 (defun delete-let (clambda)
1306 (declare (type clambda clambda))
1307 (aver (functional-letlike-p clambda))
1308 (note-unreferenced-vars clambda)
1309 (let ((call (let-combination clambda)))
1310 (flush-dest (basic-combination-fun call))
1312 (unlink-node (lambda-bind clambda))
1313 (setf (lambda-bind clambda) nil))
1316 ;;; This function is called when one of the arguments to a LET
1317 ;;; changes. We look at each changed argument. If the corresponding
1318 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1319 ;;; consider substituting for the variable, and also propagate
1320 ;;; derived-type information for the arg to all the VAR's refs.
1322 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1323 ;;; subtype of the argument's leaf type. This prevents type checking
1324 ;;; from being defeated, and also ensures that the best representation
1325 ;;; for the variable can be used.
1327 ;;; Substitution of individual references is inhibited if the
1328 ;;; reference is in a different component from the home. This can only
1329 ;;; happen with closures over top level lambda vars. In such cases,
1330 ;;; the references may have already been compiled, and thus can't be
1331 ;;; retroactively modified.
1333 ;;; If all of the variables are deleted (have no references) when we
1334 ;;; are done, then we delete the LET.
1336 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1338 (defun propagate-let-args (call fun)
1339 (declare (type combination call) (type clambda fun))
1340 (loop for arg in (combination-args call)
1341 and var in (lambda-vars fun) do
1342 (when (and arg (lvar-reoptimize arg))
1343 (setf (lvar-reoptimize arg) nil)
1345 ((lambda-var-sets var)
1346 (propagate-from-sets var (lvar-type arg)))
1347 ((let ((use (lvar-uses arg)))
1349 (let ((leaf (ref-leaf use)))
1350 (when (and (constant-reference-p use)
1351 (csubtypep (leaf-type leaf)
1352 ;; (NODE-DERIVED-TYPE USE) would
1353 ;; be better -- APD, 2003-05-15
1355 (propagate-to-refs var (lvar-type arg))
1356 (let ((use-component (node-component use)))
1357 (prog1 (substitute-leaf-if
1359 (cond ((eq (node-component ref) use-component)
1362 (aver (lambda-toplevelish-p (lambda-home fun)))
1366 ((and (null (rest (leaf-refs var)))
1367 (substitute-single-use-lvar arg var)))
1369 (propagate-to-refs var (lvar-type arg))))))
1371 (when (every #'not (combination-args call))
1376 ;;; This function is called when one of the args to a non-LET local
1377 ;;; call changes. For each changed argument corresponding to an unset
1378 ;;; variable, we compute the union of the types across all calls and
1379 ;;; propagate this type information to the var's refs.
1381 ;;; If the function has an XEP, then we don't do anything, since we
1382 ;;; won't discover anything.
1384 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1385 ;;; corresponding to changed arguments in CALL, since the only use in
1386 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1388 (defun propagate-local-call-args (call fun)
1389 (declare (type combination call) (type clambda fun))
1391 (unless (or (functional-entry-fun fun)
1392 (lambda-optional-dispatch fun))
1393 (let* ((vars (lambda-vars fun))
1394 (union (mapcar (lambda (arg var)
1396 (lvar-reoptimize arg)
1397 (null (basic-var-sets var)))
1399 (basic-combination-args call)
1401 (this-ref (lvar-use (basic-combination-fun call))))
1403 (dolist (arg (basic-combination-args call))
1405 (setf (lvar-reoptimize arg) nil)))
1407 (dolist (ref (leaf-refs fun))
1408 (let ((dest (node-dest ref)))
1409 (unless (or (eq ref this-ref) (not dest))
1411 (mapcar (lambda (this-arg old)
1413 (setf (lvar-reoptimize this-arg) nil)
1414 (type-union (lvar-type this-arg) old)))
1415 (basic-combination-args dest)
1418 (loop for var in vars
1420 when type do (propagate-to-refs var type))))
1424 ;;;; multiple values optimization
1426 ;;; Do stuff to notice a change to a MV combination node. There are
1427 ;;; two main branches here:
1428 ;;; -- If the call is local, then it is already a MV let, or should
1429 ;;; become one. Note that although all :LOCAL MV calls must eventually
1430 ;;; be converted to :MV-LETs, there can be a window when the call
1431 ;;; is local, but has not been LET converted yet. This is because
1432 ;;; the entry-point lambdas may have stray references (in other
1433 ;;; entry points) that have not been deleted yet.
1434 ;;; -- The call is full. This case is somewhat similar to the non-MV
1435 ;;; combination optimization: we propagate return type information and
1436 ;;; notice non-returning calls. We also have an optimization
1437 ;;; which tries to convert MV-CALLs into MV-binds.
1438 (defun ir1-optimize-mv-combination (node)
1439 (ecase (basic-combination-kind node)
1441 (let ((fun-lvar (basic-combination-fun node)))
1442 (when (lvar-reoptimize fun-lvar)
1443 (setf (lvar-reoptimize fun-lvar) nil)
1444 (maybe-let-convert (combination-lambda node))))
1445 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1446 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1447 (unless (convert-mv-bind-to-let node)
1448 (ir1-optimize-mv-bind node))))
1450 (let* ((fun (basic-combination-fun node))
1451 (fun-changed (lvar-reoptimize fun))
1452 (args (basic-combination-args node)))
1454 (setf (lvar-reoptimize fun) nil)
1455 (let ((type (lvar-type fun)))
1456 (when (fun-type-p type)
1457 (derive-node-type node (fun-type-returns type))))
1458 (maybe-terminate-block node nil)
1459 (let ((use (lvar-uses fun)))
1460 (when (and (ref-p use) (functional-p (ref-leaf use)))
1461 (convert-call-if-possible use node)
1462 (when (eq (basic-combination-kind node) :local)
1463 (maybe-let-convert (ref-leaf use))))))
1464 (unless (or (eq (basic-combination-kind node) :local)
1465 (eq (lvar-fun-name fun) '%throw))
1466 (ir1-optimize-mv-call node))
1468 (setf (lvar-reoptimize arg) nil))))
1472 ;;; Propagate derived type info from the values lvar to the vars.
1473 (defun ir1-optimize-mv-bind (node)
1474 (declare (type mv-combination node))
1475 (let* ((arg (first (basic-combination-args node)))
1476 (vars (lambda-vars (combination-lambda node)))
1477 (n-vars (length vars))
1478 (types (values-type-in (lvar-derived-type arg)
1480 (loop for var in vars
1482 do (if (basic-var-sets var)
1483 (propagate-from-sets var type)
1484 (propagate-to-refs var type)))
1485 (setf (lvar-reoptimize arg) nil))
1488 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1490 ;;; -- The call has only one argument, and
1491 ;;; -- The function has a known fixed number of arguments, or
1492 ;;; -- The argument yields a known fixed number of values.
1494 ;;; What we do is change the function in the MV-CALL to be a lambda
1495 ;;; that "looks like an MV bind", which allows
1496 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1497 ;;; converted (the next time around.) This new lambda just calls the
1498 ;;; actual function with the MV-BIND variables as arguments. Note that
1499 ;;; this new MV bind is not let-converted immediately, as there are
1500 ;;; going to be stray references from the entry-point functions until
1501 ;;; they get deleted.
1503 ;;; In order to avoid loss of argument count checking, we only do the
1504 ;;; transformation according to a known number of expected argument if
1505 ;;; safety is unimportant. We can always convert if we know the number
1506 ;;; of actual values, since the normal call that we build will still
1507 ;;; do any appropriate argument count checking.
1509 ;;; We only attempt the transformation if the called function is a
1510 ;;; constant reference. This allows us to just splice the leaf into
1511 ;;; the new function, instead of trying to somehow bind the function
1512 ;;; expression. The leaf must be constant because we are evaluating it
1513 ;;; again in a different place. This also has the effect of squelching
1514 ;;; multiple warnings when there is an argument count error.
1515 (defun ir1-optimize-mv-call (node)
1516 (let ((fun (basic-combination-fun node))
1517 (*compiler-error-context* node)
1518 (ref (lvar-uses (basic-combination-fun node)))
1519 (args (basic-combination-args node)))
1521 (unless (and (ref-p ref) (constant-reference-p ref)
1523 (return-from ir1-optimize-mv-call))
1525 (multiple-value-bind (min max)
1526 (fun-type-nargs (lvar-type fun))
1528 (multiple-value-bind (types nvals)
1529 (values-types (lvar-derived-type (first args)))
1530 (declare (ignore types))
1531 (if (eq nvals :unknown) nil nvals))))
1534 (when (and min (< total-nvals min))
1536 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1539 (setf (basic-combination-kind node) :error)
1540 (return-from ir1-optimize-mv-call))
1541 (when (and max (> total-nvals max))
1543 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1546 (setf (basic-combination-kind node) :error)
1547 (return-from ir1-optimize-mv-call)))
1549 (let ((count (cond (total-nvals)
1550 ((and (policy node (zerop verify-arg-count))
1555 (with-ir1-environment-from-node node
1556 (let* ((dums (make-gensym-list count))
1558 (fun (ir1-convert-lambda
1559 `(lambda (&optional ,@dums &rest ,ignore)
1560 (declare (ignore ,ignore))
1561 (funcall ,(ref-leaf ref) ,@dums)))))
1562 (change-ref-leaf ref fun)
1563 (aver (eq (basic-combination-kind node) :full))
1564 (locall-analyze-component *current-component*)
1565 (aver (eq (basic-combination-kind node) :local)))))))))
1569 ;;; (multiple-value-bind
1578 ;;; What we actually do is convert the VALUES combination into a
1579 ;;; normal LET combination calling the original :MV-LET lambda. If
1580 ;;; there are extra args to VALUES, discard the corresponding
1581 ;;; lvars. If there are insufficient args, insert references to NIL.
1582 (defun convert-mv-bind-to-let (call)
1583 (declare (type mv-combination call))
1584 (let* ((arg (first (basic-combination-args call)))
1585 (use (lvar-uses arg)))
1586 (when (and (combination-p use)
1587 (eq (lvar-fun-name (combination-fun use))
1589 (let* ((fun (combination-lambda call))
1590 (vars (lambda-vars fun))
1591 (vals (combination-args use))
1592 (nvars (length vars))
1593 (nvals (length vals)))
1594 (cond ((> nvals nvars)
1595 (mapc #'flush-dest (subseq vals nvars))
1596 (setq vals (subseq vals 0 nvars)))
1598 (with-ir1-environment-from-node use
1599 (let ((node-prev (node-prev use)))
1600 (setf (node-prev use) nil)
1601 (setf (ctran-next node-prev) nil)
1602 (collect ((res vals))
1603 (loop for count below (- nvars nvals)
1604 for prev = node-prev then ctran
1605 for ctran = (make-ctran)
1606 and lvar = (make-lvar use)
1607 do (reference-constant prev ctran lvar nil)
1609 finally (link-node-to-previous-ctran
1611 (setq vals (res)))))))
1612 (setf (combination-args use) vals)
1613 (flush-dest (combination-fun use))
1614 (let ((fun-lvar (basic-combination-fun call)))
1615 (setf (lvar-dest fun-lvar) use)
1616 (setf (combination-fun use) fun-lvar)
1617 (flush-lvar-externally-checkable-type fun-lvar))
1618 (setf (combination-kind use) :local)
1619 (setf (functional-kind fun) :let)
1620 (flush-dest (first (basic-combination-args call)))
1623 (reoptimize-lvar (first vals)))
1624 (propagate-to-args use fun)
1625 (reoptimize-call use))
1629 ;;; (values-list (list x y z))
1634 ;;; In implementation, this is somewhat similar to
1635 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1636 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1637 ;;; (allowing the LIST to be flushed.)
1639 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1640 (defoptimizer (values-list optimizer) ((list) node)
1641 (let ((use (lvar-uses list)))
1642 (when (and (combination-p use)
1643 (eq (lvar-fun-name (combination-fun use))
1646 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1647 (change-ref-leaf (lvar-uses (combination-fun node))
1648 (find-free-fun 'values "in a strange place"))
1649 (setf (combination-kind node) :full)
1650 (let ((args (combination-args use)))
1652 (setf (lvar-dest arg) node)
1653 (flush-lvar-externally-checkable-type arg))
1654 (setf (combination-args use) nil)
1656 (setf (combination-args node) args))
1659 ;;; If VALUES appears in a non-MV context, then effectively convert it
1660 ;;; to a PROG1. This allows the computation of the additional values
1661 ;;; to become dead code.
1662 (deftransform values ((&rest vals) * * :node node)
1663 (unless (lvar-single-value-p (node-lvar node))
1664 (give-up-ir1-transform))
1665 (setf (node-derived-type node) *wild-type*)
1666 (principal-lvar-single-valuify (node-lvar node))
1668 (let ((dummies (make-gensym-list (length (cdr vals)))))
1669 `(lambda (val ,@dummies)
1670 (declare (ignore ,@dummies))
1676 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1677 (declare (type cast cast))
1678 (let* ((value (cast-value cast))
1679 (value-type (lvar-derived-type value))
1680 (atype (cast-asserted-type cast))
1681 (int (values-type-intersection value-type atype)))
1682 (derive-node-type cast int)
1683 (when (eq int *empty-type*)
1684 (unless (eq value-type *empty-type*)
1686 ;; FIXME: Do it in one step.
1689 `(multiple-value-call #'list 'dummy))
1692 ;; FIXME: Derived type.
1693 `(%compile-time-type-error 'dummy
1694 ',(type-specifier atype)
1695 ',(type-specifier value-type)))
1696 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1697 ;; functions, so we declare the return type of
1698 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1700 (setq value (cast-value cast))
1701 (derive-node-type (lvar-uses value) *empty-type*)
1702 (maybe-terminate-block (lvar-uses value) nil)
1703 ;; FIXME: Is it necessary?
1704 (aver (null (block-pred (node-block cast))))
1705 (setf (block-delete-p (node-block cast)) t)
1706 (return-from ir1-optimize-cast)))
1707 (when (eq (node-derived-type cast) *empty-type*)
1708 (maybe-terminate-block cast nil))
1710 (when (not do-not-optimize)
1711 (let ((lvar (node-lvar cast)))
1712 (when (values-subtypep value-type (cast-asserted-type cast))
1713 (delete-filter cast lvar value)
1715 (reoptimize-lvar lvar)
1716 (when (lvar-single-value-p lvar)
1717 (note-single-valuified-lvar lvar)))
1718 (return-from ir1-optimize-cast t))
1720 (when (and (listp (lvar-uses value))
1722 ;; Pathwise removing of CAST
1723 (let ((ctran (node-next cast))
1724 (dest (lvar-dest lvar))
1727 (do-uses (use value)
1728 (when (and (values-subtypep (node-derived-type use) atype)
1729 (immediately-used-p value use))
1731 (when ctran (ensure-block-start ctran))
1732 (setq next-block (first (block-succ (node-block cast)))))
1733 (%delete-lvar-use use)
1734 (add-lvar-use use lvar)
1735 (unlink-blocks (node-block use) (node-block cast))
1736 (link-blocks (node-block use) next-block)
1737 (when (and (return-p dest)
1738 (basic-combination-p use)
1739 (eq (basic-combination-kind use) :local))
1741 (dolist (use (merges))
1742 (merge-tail-sets use)))))))
1744 (when (and (cast-%type-check cast)
1745 (values-subtypep value-type
1746 (cast-type-to-check cast)))
1747 (setf (cast-%type-check cast) nil)))
1749 (unless do-not-optimize
1750 (setf (node-reoptimize cast) nil)))