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)
24 (declare (type (or lvar null) thing))
26 (let ((use (principal-lvar-use thing)))
27 (and (ref-p use) (constant-p (ref-leaf use))))))
29 ;;; Return the constant value for an LVAR whose only use is a constant
31 (declaim (ftype (function (lvar) t) lvar-value))
32 (defun lvar-value (lvar)
33 (let ((use (principal-lvar-use lvar)))
34 (constant-value (ref-leaf use))))
36 ;;;; interface for obtaining results of type inference
38 ;;; Our best guess for the type of this lvar's value. Note that this
39 ;;; may be VALUES or FUNCTION type, which cannot be passed as an
40 ;;; argument to the normal type operations. See LVAR-TYPE.
42 ;;; The result value is cached in the LVAR-%DERIVED-TYPE slot. If the
43 ;;; slot is true, just return that value, otherwise recompute and
44 ;;; stash the value there.
45 #!-sb-fluid (declaim (inline lvar-derived-type))
46 (defun lvar-derived-type (lvar)
47 (declare (type lvar lvar))
48 (or (lvar-%derived-type lvar)
49 (setf (lvar-%derived-type lvar)
50 (%lvar-derived-type lvar))))
51 (defun %lvar-derived-type (lvar)
52 (declare (type lvar lvar))
53 (let ((uses (lvar-uses lvar)))
54 (cond ((null uses) *empty-type*)
56 (do ((res (node-derived-type (first uses))
57 (values-type-union (node-derived-type (first current))
59 (current (rest uses) (rest current)))
60 ((null current) res)))
62 (node-derived-type (lvar-uses lvar))))))
64 ;;; Return the derived type for LVAR's first value. This is guaranteed
65 ;;; not to be a VALUES or FUNCTION type.
66 (declaim (ftype (sfunction (lvar) ctype) lvar-type))
67 (defun lvar-type (lvar)
68 (single-value-type (lvar-derived-type lvar)))
70 ;;; If LVAR is an argument of a function, return a type which the
71 ;;; function checks LVAR for.
72 #!-sb-fluid (declaim (inline lvar-externally-checkable-type))
73 (defun lvar-externally-checkable-type (lvar)
74 (or (lvar-%externally-checkable-type lvar)
75 (%lvar-%externally-checkable-type lvar)))
76 (defun %lvar-%externally-checkable-type (lvar)
77 (declare (type lvar lvar))
78 (let ((dest (lvar-dest lvar)))
79 (if (not (and dest (combination-p dest)))
80 ;; TODO: MV-COMBINATION
81 (setf (lvar-%externally-checkable-type lvar) *wild-type*)
82 (let* ((fun (combination-fun dest))
83 (args (combination-args dest))
84 (fun-type (lvar-type fun)))
85 (setf (lvar-%externally-checkable-type fun) *wild-type*)
86 (if (or (not (call-full-like-p dest))
87 (not (fun-type-p fun-type))
88 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
89 (fun-type-wild-args fun-type))
92 (setf (lvar-%externally-checkable-type arg)
94 (map-combination-args-and-types
96 (setf (lvar-%externally-checkable-type arg)
97 (acond ((lvar-%externally-checkable-type arg)
98 (values-type-intersection
99 it (coerce-to-values type)))
100 (t (coerce-to-values type)))))
102 (lvar-%externally-checkable-type lvar))
103 #!-sb-fluid(declaim (inline flush-lvar-externally-checkable-type))
104 (defun flush-lvar-externally-checkable-type (lvar)
105 (declare (type lvar lvar))
106 (setf (lvar-%externally-checkable-type lvar) nil))
108 ;;;; interface routines used by optimizers
110 (declaim (inline reoptimize-component))
111 (defun reoptimize-component (component kind)
112 (declare (type component component)
113 (type (member nil :maybe t) kind))
115 (unless (eq (component-reoptimize component) t)
116 (setf (component-reoptimize component) kind)))
118 ;;; This function is called by optimizers to indicate that something
119 ;;; interesting has happened to the value of LVAR. Optimizers must
120 ;;; make sure that they don't call for reoptimization when nothing has
121 ;;; happened, since optimization will fail to terminate.
123 ;;; We clear any cached type for the lvar and set the reoptimize flags
124 ;;; on everything in sight.
125 (defun reoptimize-lvar (lvar)
126 (declare (type (or lvar null) lvar))
128 (setf (lvar-%derived-type lvar) nil)
129 (let ((dest (lvar-dest lvar)))
131 (setf (lvar-reoptimize lvar) t)
132 (setf (node-reoptimize dest) t)
133 (binding* (;; Since this may be called during IR1 conversion,
134 ;; PREV may be missing.
135 (prev (node-prev dest) :exit-if-null)
136 (block (ctran-block prev))
137 (component (block-component block)))
138 (when (typep dest 'cif)
139 (setf (block-test-modified block) t))
140 (setf (block-reoptimize block) t)
141 (reoptimize-component component :maybe))))
143 (setf (block-type-check (node-block node)) t)))
146 (defun reoptimize-lvar-uses (lvar)
147 (declare (type lvar lvar))
149 (setf (node-reoptimize use) t)
150 (setf (block-reoptimize (node-block use)) t)
151 (reoptimize-component (node-component use) :maybe)))
153 ;;; Annotate NODE to indicate that its result has been proven to be
154 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
155 ;;; only correct way to supply information discovered about a node's
156 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
157 ;;; information may be lost and reoptimization may not happen.
159 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
160 ;;; intersection is different from the old type, then we do a
161 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
162 (defun derive-node-type (node rtype)
163 (declare (type valued-node node) (type ctype rtype))
164 (let ((node-type (node-derived-type node)))
165 (unless (eq node-type rtype)
166 (let ((int (values-type-intersection node-type rtype))
167 (lvar (node-lvar node)))
168 (when (type/= node-type int)
169 (when (and *check-consistency*
170 (eq int *empty-type*)
171 (not (eq rtype *empty-type*)))
172 (let ((*compiler-error-context* node))
174 "New inferred type ~S conflicts with old type:~
175 ~% ~S~%*** possible internal error? Please report this."
176 (type-specifier rtype) (type-specifier node-type))))
177 (setf (node-derived-type node) int)
178 ;; If the new type consists of only one object, replace the
179 ;; node with a constant reference.
180 (when (and (ref-p node)
181 (lambda-var-p (ref-leaf node)))
182 (let ((type (single-value-type int)))
183 (when (and (member-type-p type)
184 (null (rest (member-type-members type))))
185 (change-ref-leaf node (find-constant
186 (first (member-type-members type)))))))
187 (reoptimize-lvar lvar)))))
190 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
191 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
192 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
193 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
194 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
195 (defun assert-lvar-type (lvar type policy)
196 (declare (type lvar lvar) (type ctype type))
197 (unless (values-subtypep (lvar-derived-type lvar) type)
198 (let* ((dest (lvar-dest lvar))
199 (ctran (node-prev dest)))
200 (with-ir1-environment-from-node dest
201 (let* ((cast (make-cast lvar type policy))
202 (internal-lvar (make-lvar))
203 (internal-ctran (make-ctran)))
204 (setf (ctran-next ctran) cast
205 (node-prev cast) ctran)
206 (use-continuation cast internal-ctran internal-lvar)
207 (link-node-to-previous-ctran dest internal-ctran)
208 (substitute-lvar internal-lvar lvar)
209 (setf (lvar-dest lvar) cast)
210 (reoptimize-lvar lvar)
211 (when (return-p dest)
212 (node-ends-block cast))
213 (setf (block-attributep (block-flags (node-block cast))
214 type-check type-asserted)
220 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
221 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
222 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
223 ;;; we are done, then another iteration would be beneficial.
224 (defun ir1-optimize (component fastp)
225 (declare (type component component))
226 (setf (component-reoptimize component) nil)
227 (loop with block = (block-next (component-head component))
228 with tail = (component-tail component)
229 for last-block = block
230 until (eq block tail)
232 ;; We delete blocks when there is either no predecessor or the
233 ;; block is in a lambda that has been deleted. These blocks
234 ;; would eventually be deleted by DFO recomputation, but doing
235 ;; it here immediately makes the effect available to IR1
237 ((or (block-delete-p block)
238 (null (block-pred block)))
239 (delete-block-lazily block)
240 (setq block (clean-component component block)))
241 ((eq (functional-kind (block-home-lambda block)) :deleted)
242 ;; Preserve the BLOCK-SUCC invariant that almost every block has
243 ;; one successor (and a block with DELETE-P set is an acceptable
245 (mark-for-deletion block)
246 (setq block (clean-component component block)))
249 (let ((succ (block-succ block)))
250 (unless (singleton-p succ)
253 (let ((last (block-last block)))
256 (flush-dest (if-test last))
257 (when (unlink-node last)
260 (when (maybe-delete-exit last)
263 (unless (join-successor-if-possible block)
266 (when (and (not fastp) (block-reoptimize block) (block-component block))
267 (aver (not (block-delete-p block)))
268 (ir1-optimize-block block))
270 (cond ((and (block-delete-p block) (block-component block))
271 (setq block (clean-component component block)))
272 ((and (block-flush-p block) (block-component block))
273 (flush-dead-code block)))))
274 do (when (eq block last-block)
275 (setq block (block-next 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 nil 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
316 (let ((value (exit-value node)))
318 (derive-node-type node (lvar-derived-type value)))))
320 (ir1-optimize-set node))
322 (ir1-optimize-cast node)))))
326 ;;; Try to join with a successor block. If we succeed, we return true,
328 (defun join-successor-if-possible (block)
329 (declare (type cblock block))
330 (let ((next (first (block-succ block))))
331 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
332 (cond ( ;; We cannot combine with a successor block if:
334 ;; the successor has more than one predecessor;
335 (rest (block-pred next))
336 ;; the successor is the current block (infinite loop);
338 ;; the next block has a different cleanup, and thus
339 ;; we may want to insert cleanup code between the
340 ;; two blocks at some point;
341 (not (eq (block-end-cleanup block)
342 (block-start-cleanup next)))
343 ;; the next block has a different home lambda, and
344 ;; thus the control transfer is a non-local exit.
345 (not (eq (block-home-lambda block)
346 (block-home-lambda next)))
347 ;; Stack analysis phase wants ENTRY to start a block...
348 (entry-p (block-start-node next))
349 (let ((last (block-last block)))
350 (and (valued-node-p last)
351 (awhen (node-lvar last)
353 ;; ... and a DX-allocator to end a block.
354 (lvar-dynamic-extent it)
355 ;; FIXME: This is a partial workaround for bug 303.
356 (consp (lvar-uses it)))))))
359 (join-blocks block next)
362 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
363 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
364 ;;; for the two blocks so that any indicated optimization gets done.
365 (defun join-blocks (block1 block2)
366 (declare (type cblock block1 block2))
367 (let* ((last1 (block-last block1))
368 (last2 (block-last block2))
369 (succ (block-succ block2))
370 (start2 (block-start block2)))
371 (do ((ctran start2 (node-next (ctran-next ctran))))
373 (setf (ctran-block ctran) block1))
375 (unlink-blocks block1 block2)
377 (unlink-blocks block2 block)
378 (link-blocks block1 block))
380 (setf (ctran-kind start2) :inside-block)
381 (setf (node-next last1) start2)
382 (setf (ctran-use start2) last1)
383 (setf (block-last block1) last2))
385 (setf (block-flags block1)
386 (attributes-union (block-flags block1)
388 (block-attributes type-asserted test-modified)))
390 (let ((next (block-next block2))
391 (prev (block-prev block2)))
392 (setf (block-next prev) next)
393 (setf (block-prev next) prev))
397 ;;; Delete any nodes in BLOCK whose value is unused and which have no
398 ;;; side effects. We can delete sets of lexical variables when the set
399 ;;; variable has no references.
400 (defun flush-dead-code (block)
401 (declare (type cblock block))
402 (setf (block-flush-p block) nil)
403 (do-nodes-backwards (node lvar block :restart-p t)
410 (let ((kind (combination-kind node))
411 (info (combination-fun-info node)))
412 (when (and (eq kind :known) (fun-info-p info))
413 (let ((attr (fun-info-attributes info)))
414 (when (and (not (ir1-attributep attr call))
415 ;; ### For now, don't delete potentially
416 ;; flushable calls when they have the CALL
417 ;; attribute. Someday we should look at the
418 ;; functional args to determine if they have
420 (if (policy node (= safety 3))
421 (ir1-attributep attr flushable)
422 (ir1-attributep attr unsafely-flushable)))
423 (flush-combination node))))))
425 (when (eq (basic-combination-kind node) :local)
426 (let ((fun (combination-lambda node)))
427 (when (dolist (var (lambda-vars fun) t)
428 (when (or (leaf-refs var)
429 (lambda-var-sets var))
431 (flush-dest (first (basic-combination-args node)))
434 (let ((value (exit-value node)))
437 (setf (exit-value node) nil))))
439 (let ((var (set-var node)))
440 (when (and (lambda-var-p var)
441 (null (leaf-refs var)))
442 (flush-dest (set-value node))
443 (setf (basic-var-sets var)
444 (delq node (basic-var-sets var)))
445 (unlink-node node))))
447 (unless (cast-type-check node)
448 (flush-dest (cast-value node))
449 (unlink-node node))))))
453 ;;;; local call return type propagation
455 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
456 ;;; flag set. It iterates over the uses of the RESULT, looking for
457 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
458 ;;; call, then we union its type together with the types of other such
459 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
460 ;;; type with the RESULT's asserted type. We can make this
461 ;;; intersection now (potentially before type checking) because this
462 ;;; assertion on the result will eventually be checked (if
465 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
466 ;;; combination, which may change the succesor of the call to be the
467 ;;; called function, and if so, checks if the call can become an
468 ;;; assignment. If we convert to an assignment, we abort, since the
469 ;;; RETURN has been deleted.
470 (defun find-result-type (node)
471 (declare (type creturn node))
472 (let ((result (return-result node)))
473 (collect ((use-union *empty-type* values-type-union))
474 (do-uses (use result)
475 (let ((use-home (node-home-lambda use)))
476 (cond ((or (eq (functional-kind use-home) :deleted)
477 (block-delete-p (node-block use))))
478 ((and (basic-combination-p use)
479 (eq (basic-combination-kind use) :local))
480 (aver (eq (lambda-tail-set use-home)
481 (lambda-tail-set (combination-lambda use))))
482 (when (combination-p use)
483 (when (nth-value 1 (maybe-convert-tail-local-call use))
484 (return-from find-result-type t))))
486 (use-union (node-derived-type use))))))
488 ;; (values-type-intersection
489 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
493 (setf (return-result-type node) int))))
496 ;;; Do stuff to realize that something has changed about the value
497 ;;; delivered to a return node. Since we consider the return values of
498 ;;; all functions in the tail set to be equivalent, this amounts to
499 ;;; bringing the entire tail set up to date. We iterate over the
500 ;;; returns for all the functions in the tail set, reanalyzing them
501 ;;; all (not treating NODE specially.)
503 ;;; When we are done, we check whether the new type is different from
504 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
505 ;;; all the lvars for references to functions in the tail set. This
506 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
507 ;;; results of the calls.
508 (defun ir1-optimize-return (node)
509 (declare (type creturn node))
512 (let* ((tails (lambda-tail-set (return-lambda node)))
513 (funs (tail-set-funs tails)))
514 (collect ((res *empty-type* values-type-union))
516 (let ((return (lambda-return fun)))
518 (when (node-reoptimize return)
519 (setf (node-reoptimize return) nil)
520 (when (find-result-type return)
522 (res (return-result-type return)))))
524 (when (type/= (res) (tail-set-type tails))
525 (setf (tail-set-type tails) (res))
526 (dolist (fun (tail-set-funs tails))
527 (dolist (ref (leaf-refs fun))
528 (reoptimize-lvar (node-lvar ref))))))))
534 ;;; If the test has multiple uses, replicate the node when possible.
535 ;;; Also check whether the predicate is known to be true or false,
536 ;;; deleting the IF node in favor of the appropriate branch when this
538 (defun ir1-optimize-if (node)
539 (declare (type cif node))
540 (let ((test (if-test node))
541 (block (node-block node)))
543 (when (and (eq (block-start-node block) node)
544 (listp (lvar-uses test)))
546 (when (immediately-used-p test use)
547 (convert-if-if use node)
548 (when (not (listp (lvar-uses test))) (return)))))
550 (let* ((type (lvar-type test))
552 (cond ((constant-lvar-p test)
553 (if (lvar-value test)
554 (if-alternative node)
555 (if-consequent node)))
556 ((not (types-equal-or-intersect type (specifier-type 'null)))
557 (if-alternative node))
558 ((type= type (specifier-type 'null))
559 (if-consequent node)))))
562 (when (rest (block-succ block))
563 (unlink-blocks block victim))
564 (setf (component-reanalyze (node-component node)) t)
565 (unlink-node node))))
568 ;;; Create a new copy of an IF node that tests the value of the node
569 ;;; USE. The test must have >1 use, and must be immediately used by
570 ;;; USE. NODE must be the only node in its block (implying that
571 ;;; block-start = if-test).
573 ;;; This optimization has an effect semantically similar to the
574 ;;; source-to-source transformation:
575 ;;; (IF (IF A B C) D E) ==>
576 ;;; (IF A (IF B D E) (IF C D E))
578 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
579 ;;; node so that dead code deletion notes will definitely not consider
580 ;;; either node to be part of the original source. One node might
581 ;;; become unreachable, resulting in a spurious note.
582 (defun convert-if-if (use node)
583 (declare (type node use) (type cif node))
584 (with-ir1-environment-from-node node
585 (let* ((block (node-block node))
586 (test (if-test node))
587 (cblock (if-consequent node))
588 (ablock (if-alternative node))
589 (use-block (node-block use))
590 (new-ctran (make-ctran))
591 (new-lvar (make-lvar))
592 (new-node (make-if :test new-lvar
594 :alternative ablock))
595 (new-block (ctran-starts-block new-ctran)))
596 (link-node-to-previous-ctran new-node new-ctran)
597 (setf (lvar-dest new-lvar) new-node)
598 (setf (block-last new-block) new-node)
600 (unlink-blocks use-block block)
601 (%delete-lvar-use use)
602 (add-lvar-use use new-lvar)
603 (link-blocks use-block new-block)
605 (link-blocks new-block cblock)
606 (link-blocks new-block ablock)
608 (push "<IF Duplication>" (node-source-path node))
609 (push "<IF Duplication>" (node-source-path new-node))
611 (reoptimize-lvar test)
612 (reoptimize-lvar new-lvar)
613 (setf (component-reanalyze *current-component*) t)))
616 ;;;; exit IR1 optimization
618 ;;; This function attempts to delete an exit node, returning true if
619 ;;; it deletes the block as a consequence:
620 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
621 ;;; anything, since there is nothing to be done.
622 ;;; -- If the exit node and its ENTRY have the same home lambda then
623 ;;; we know the exit is local, and can delete the exit. We change
624 ;;; uses of the Exit-Value to be uses of the original lvar,
625 ;;; then unlink the node. If the exit is to a TR context, then we
626 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
627 ;;; their value to this exit.
628 ;;; -- If there is no value (as in a GO), then we skip the value
631 ;;; This function is also called by environment analysis, since it
632 ;;; wants all exits to be optimized even if normal optimization was
634 (defun maybe-delete-exit (node)
635 (declare (type exit node))
636 (let ((value (exit-value node))
637 (entry (exit-entry node)))
639 (eq (node-home-lambda node) (node-home-lambda entry)))
640 (setf (entry-exits entry) (delq node (entry-exits entry)))
642 (delete-filter node (node-lvar node) value)
643 (unlink-node node)))))
646 ;;;; combination IR1 optimization
648 ;;; Report as we try each transform?
650 (defvar *show-transforms-p* nil)
652 ;;; Do IR1 optimizations on a COMBINATION node.
653 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
654 (defun ir1-optimize-combination (node)
655 (when (lvar-reoptimize (basic-combination-fun node))
656 (propagate-fun-change node)
657 (maybe-terminate-block node nil))
658 (let ((args (basic-combination-args node))
659 (kind (basic-combination-kind node))
660 (info (basic-combination-fun-info node)))
663 (let ((fun (combination-lambda node)))
664 (if (eq (functional-kind fun) :let)
665 (propagate-let-args node fun)
666 (propagate-local-call-args node fun))))
670 (setf (lvar-reoptimize arg) nil))))
674 (setf (lvar-reoptimize arg) nil)))
676 (let ((fun (fun-info-derive-type info)))
678 (let ((res (funcall fun node)))
680 (derive-node-type node (coerce-to-values res))
681 (maybe-terminate-block node nil)))))))
686 (setf (lvar-reoptimize arg) nil)))
688 (let ((attr (fun-info-attributes info)))
689 (when (and (ir1-attributep attr foldable)
690 ;; KLUDGE: The next test could be made more sensitive,
691 ;; only suppressing constant-folding of functions with
692 ;; CALL attributes when they're actually passed
693 ;; function arguments. -- WHN 19990918
694 (not (ir1-attributep attr call))
695 (every #'constant-lvar-p args)
697 ;; Even if the function is foldable in principle,
698 ;; it might be one of our low-level
699 ;; implementation-specific functions. Such
700 ;; functions don't necessarily exist at runtime on
701 ;; a plain vanilla ANSI Common Lisp
702 ;; cross-compilation host, in which case the
703 ;; cross-compiler can't fold it because the
704 ;; cross-compiler doesn't know how to evaluate it.
706 (or (fboundp (combination-fun-source-name node))
707 (progn (format t ";;; !!! Unbound fun: (~S~{ ~S~})~%"
708 (combination-fun-source-name node)
709 (mapcar #'lvar-value args))
711 (constant-fold-call node)
712 (return-from ir1-optimize-combination)))
714 (let ((fun (fun-info-derive-type info)))
716 (let ((res (funcall fun node)))
718 (derive-node-type node (coerce-to-values res))
719 (maybe-terminate-block node nil)))))
721 (let ((fun (fun-info-optimizer info)))
722 (unless (and fun (funcall fun node))
723 (dolist (x (fun-info-transforms info))
725 (when *show-transforms-p*
726 (let* ((lvar (basic-combination-fun node))
727 (fname (lvar-fun-name lvar 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 NODE doesn't return (i.e. return type is NIL), then terminate
738 ;;; the block there, and link it to the component tail.
740 ;;; Except when called during IR1 convertion, we delete the
741 ;;; continuation if it has no other uses. (If it does have other uses,
744 ;;; Termination on the basis of a continuation type is
746 ;;; -- The continuation is deleted (hence the assertion is spurious), or
747 ;;; -- We are in IR1 conversion (where THE assertions are subject to
748 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
749 ;;; uses can(?) be added later. -- APD, 2003-07-17
751 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
752 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
753 (declare (type (or basic-combination cast ref) node))
754 (let* ((block (node-block node))
755 (lvar (node-lvar node))
756 (ctran (node-next node))
757 (tail (component-tail (block-component block)))
758 (succ (first (block-succ block))))
759 (declare (ignore lvar))
760 (unless (or (and (eq node (block-last block)) (eq succ tail))
761 (block-delete-p block))
762 (when (eq (node-derived-type node) *empty-type*)
763 (cond (ir1-converting-not-optimizing-p
766 (aver (eq (block-last block) node)))
768 (setf (block-last block) node)
769 (setf (ctran-use ctran) nil)
770 (setf (ctran-kind ctran) :unused)
771 (setf (ctran-block ctran) nil)
772 (setf (node-next node) nil)
773 (link-blocks block (ctran-starts-block ctran)))))
775 (node-ends-block node)))
777 (let ((succ (first (block-succ block))))
778 (unlink-blocks block succ)
779 (setf (component-reanalyze (block-component block)) t)
780 (aver (not (block-succ block)))
781 (link-blocks block tail)
782 (cond (ir1-converting-not-optimizing-p
783 (%delete-lvar-use node))
784 (t (delete-lvar-use node)
785 (when (null (block-pred succ))
786 (mark-for-deletion succ)))))
789 ;;; This is called both by IR1 conversion and IR1 optimization when
790 ;;; they have verified the type signature for the call, and are
791 ;;; wondering if something should be done to special-case the call. If
792 ;;; CALL is a call to a global function, then see whether it defined
794 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
795 ;;; the expansion and change the call to call it. Expansion is
796 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
797 ;;; true, we never expand, since this function has already been
798 ;;; converted. Local call analysis will duplicate the definition
799 ;;; if necessary. We claim that the parent form is LABELS for
800 ;;; context declarations, since we don't want it to be considered
801 ;;; a real global function.
802 ;;; -- If it is a known function, mark it as such by setting the KIND.
804 ;;; We return the leaf referenced (NIL if not a leaf) and the
805 ;;; FUN-INFO assigned.
806 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
807 (declare (type combination call))
808 (let* ((ref (lvar-uses (basic-combination-fun call)))
809 (leaf (when (ref-p ref) (ref-leaf ref)))
810 (inlinep (if (defined-fun-p leaf)
811 (defined-fun-inlinep leaf)
814 ((eq inlinep :notinline)
815 (let ((info (info :function :info (leaf-source-name leaf))))
817 (setf (basic-combination-fun-info call) info))
819 ((not (and (global-var-p leaf)
820 (eq (global-var-kind leaf) :global-function)))
825 ((nil :maybe-inline) (policy call (zerop space))))
827 (defined-fun-inline-expansion leaf)
828 (let ((fun (defined-fun-functional leaf)))
830 (and (eq inlinep :inline) (functional-kind fun))))
831 (inline-expansion-ok call))
832 (flet (;; FIXME: Is this what the old CMU CL internal documentation
833 ;; called semi-inlining? A more descriptive name would
834 ;; be nice. -- WHN 2002-01-07
836 (let ((res (let ((*allow-instrumenting* t))
837 (ir1-convert-lambda-for-defun
838 (defined-fun-inline-expansion leaf)
840 #'ir1-convert-inline-lambda))))
841 (setf (defined-fun-functional leaf) res)
842 (change-ref-leaf ref res))))
843 (if ir1-converting-not-optimizing-p
845 (with-ir1-environment-from-node call
847 (locall-analyze-component *current-component*))))
849 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
852 (let ((info (info :function :info (leaf-source-name leaf))))
856 (setf (basic-combination-kind call) :known)
857 (setf (basic-combination-fun-info call) info)))
858 (values leaf nil)))))))
860 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
861 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
862 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
863 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
864 ;;; syntax check, arg/result type processing, but still call
865 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
866 ;;; and that checking is done by local call analysis.
867 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
868 (declare (type combination call) (type ctype type))
869 (cond ((not (fun-type-p type))
870 (aver (multiple-value-bind (val win)
871 (csubtypep type (specifier-type 'function))
873 (recognize-known-call call ir1-converting-not-optimizing-p))
874 ((valid-fun-use call type
875 :argument-test #'always-subtypep
877 ;; KLUDGE: Common Lisp is such a dynamic
878 ;; language that all we can do here in
879 ;; general is issue a STYLE-WARNING. It
880 ;; would be nice to issue a full WARNING
881 ;; in the special case of of type
882 ;; mismatches within a compilation unit
883 ;; (as in section 3.2.2.3 of the spec)
884 ;; but at least as of sbcl-0.6.11, we
885 ;; don't keep track of whether the
886 ;; mismatched data came from the same
887 ;; compilation unit, so we can't do that.
890 ;; FIXME: Actually, I think we could
891 ;; issue a full WARNING if the call
892 ;; violates a DECLAIM FTYPE.
893 :lossage-fun #'compiler-style-warn
894 :unwinnage-fun #'compiler-notify)
895 (assert-call-type call type)
896 (maybe-terminate-block call ir1-converting-not-optimizing-p)
897 (recognize-known-call call ir1-converting-not-optimizing-p))
899 (setf (combination-kind call) :error)
902 ;;; This is called by IR1-OPTIMIZE when the function for a call has
903 ;;; changed. If the call is local, we try to LET-convert it, and
904 ;;; derive the result type. If it is a :FULL call, we validate it
905 ;;; against the type, which recognizes known calls, does inline
906 ;;; expansion, etc. If a call to a predicate in a non-conditional
907 ;;; position or to a function with a source transform, then we
908 ;;; reconvert the form to give IR1 another chance.
909 (defun propagate-fun-change (call)
910 (declare (type combination call))
911 (let ((*compiler-error-context* call)
912 (fun-lvar (basic-combination-fun call)))
913 (setf (lvar-reoptimize fun-lvar) nil)
914 (case (combination-kind call)
916 (let ((fun (combination-lambda call)))
917 (maybe-let-convert fun)
918 (unless (member (functional-kind fun) '(:let :assignment :deleted))
919 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
921 (multiple-value-bind (leaf info)
922 (validate-call-type call (lvar-type fun-lvar) nil)
923 (cond ((functional-p leaf)
924 (convert-call-if-possible
925 (lvar-uses (basic-combination-fun call))
928 ((and (global-var-p leaf)
929 (eq (global-var-kind leaf) :global-function)
930 (leaf-has-source-name-p leaf)
931 (or (info :function :source-transform (leaf-source-name leaf))
933 (ir1-attributep (fun-info-attributes info)
935 (let ((lvar (node-lvar call)))
936 (and lvar (not (if-p (lvar-dest lvar))))))))
937 (let ((name (leaf-source-name leaf))
938 (dummies (make-gensym-list
939 (length (combination-args call)))))
942 (,@(if (symbolp name)
946 (leaf-source-name leaf)))))))))
949 ;;;; known function optimization
951 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
952 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
953 ;;; replace it, otherwise add a new one.
954 (defun record-optimization-failure (node transform args)
955 (declare (type combination node) (type transform transform)
956 (type (or fun-type list) args))
957 (let* ((table (component-failed-optimizations *component-being-compiled*))
958 (found (assoc transform (gethash node table))))
960 (setf (cdr found) args)
961 (push (cons transform args) (gethash node table))))
964 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
965 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
966 ;;; doing the transform for some reason and FLAME is true, then we
967 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
968 ;;; finalize to pick up. We return true if the transform failed, and
969 ;;; thus further transformation should be attempted. We return false
970 ;;; if either the transform succeeded or was aborted.
971 (defun ir1-transform (node transform)
972 (declare (type combination node) (type transform transform))
973 (let* ((type (transform-type transform))
974 (fun (transform-function transform))
975 (constrained (fun-type-p type))
976 (table (component-failed-optimizations *component-being-compiled*))
977 (flame (if (transform-important transform)
978 (policy node (>= speed inhibit-warnings))
979 (policy node (> speed inhibit-warnings))))
980 (*compiler-error-context* node))
981 (cond ((or (not constrained)
982 (valid-fun-use node type))
983 (multiple-value-bind (severity args)
984 (catch 'give-up-ir1-transform
987 (combination-fun-source-name node))
994 (setf (combination-kind node) :error)
1002 (record-optimization-failure node transform args))
1003 (setf (gethash node table)
1004 (remove transform (gethash node table) :key #'car)))
1007 (remhash node table)
1012 :argument-test #'types-equal-or-intersect
1013 :result-test #'values-types-equal-or-intersect))
1014 (record-optimization-failure node transform type)
1019 ;;; When we don't like an IR1 transform, we throw the severity/reason
1022 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1023 ;;; aborting this attempt to transform the call, but admitting the
1024 ;;; possibility that this or some other transform will later succeed.
1025 ;;; If arguments are supplied, they are format arguments for an
1026 ;;; efficiency note.
1028 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1029 ;;; force a normal call to the function at run time. No further
1030 ;;; optimizations will be attempted.
1032 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1033 ;;; delay the transform on the node until later. REASONS specifies
1034 ;;; when the transform will be later retried. The :OPTIMIZE reason
1035 ;;; causes the transform to be delayed until after the current IR1
1036 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1037 ;;; be delayed until after constraint propagation.
1039 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1040 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1041 ;;; do CASE operations on the various REASON values, it might be a
1042 ;;; good idea to go OO, representing the reasons by objects, using
1043 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1044 ;;; SIGNAL instead of THROW.
1045 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1046 (defun give-up-ir1-transform (&rest args)
1047 (throw 'give-up-ir1-transform (values :failure args)))
1048 (defun abort-ir1-transform (&rest args)
1049 (throw 'give-up-ir1-transform (values :aborted args)))
1050 (defun delay-ir1-transform (node &rest reasons)
1051 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1053 (setf *delayed-ir1-transforms*
1054 (acons node reasons *delayed-ir1-transforms*))
1055 (throw 'give-up-ir1-transform :delayed))
1057 (dolist (reason reasons)
1058 (pushnew reason (cdr assoc)))
1059 (throw 'give-up-ir1-transform :delayed)))))
1061 ;;; Clear any delayed transform with no reasons - these should have
1062 ;;; been tried in the last pass. Then remove the reason from the
1063 ;;; delayed transform reasons, and if any become empty then set
1064 ;;; reoptimize flags for the node. Return true if any transforms are
1066 (defun retry-delayed-ir1-transforms (reason)
1067 (setf *delayed-ir1-transforms*
1068 (remove-if-not #'cdr *delayed-ir1-transforms*))
1069 (let ((reoptimize nil))
1070 (dolist (assoc *delayed-ir1-transforms*)
1071 (let ((reasons (remove reason (cdr assoc))))
1072 (setf (cdr assoc) reasons)
1074 (let ((node (car assoc)))
1075 (unless (node-deleted node)
1077 (setf (node-reoptimize node) t)
1078 (let ((block (node-block node)))
1079 (setf (block-reoptimize block) t)
1080 (reoptimize-component (block-component block) :maybe)))))))
1083 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1084 ;;; environment, and then install it as the function for the call
1085 ;;; NODE. We do local call analysis so that the new function is
1086 ;;; integrated into the control flow.
1088 ;;; We require the original function source name in order to generate
1089 ;;; a meaningful debug name for the lambda we set up. (It'd be
1090 ;;; possible to do this starting from debug names as well as source
1091 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1092 ;;; generality, since source names are always known to our callers.)
1093 (defun transform-call (call res source-name)
1094 (declare (type combination call) (list res))
1095 (aver (and (legal-fun-name-p source-name)
1096 (not (eql source-name '.anonymous.))))
1097 (node-ends-block call)
1098 (with-ir1-environment-from-node call
1099 (with-component-last-block (*current-component*
1100 (block-next (node-block call)))
1101 (let ((new-fun (ir1-convert-inline-lambda
1103 :debug-name (debug-namify "LAMBDA-inlined "
1105 "<unknown function>")))
1106 (ref (lvar-use (combination-fun call))))
1107 (change-ref-leaf ref new-fun)
1108 (setf (combination-kind call) :full)
1109 (locall-analyze-component *current-component*))))
1112 ;;; Replace a call to a foldable function of constant arguments with
1113 ;;; the result of evaluating the form. If there is an error during the
1114 ;;; evaluation, we give a warning and leave the call alone, making the
1115 ;;; call a :ERROR call.
1117 ;;; If there is more than one value, then we transform the call into a
1119 (defun constant-fold-call (call)
1120 (let ((args (mapcar #'lvar-value (combination-args call)))
1121 (fun-name (combination-fun-source-name call)))
1122 (multiple-value-bind (values win)
1123 (careful-call fun-name
1126 ;; Note: CMU CL had COMPILER-WARN here, and that
1127 ;; seems more natural, but it's probably not.
1129 ;; It's especially not while bug 173 exists:
1132 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1134 ;; can cause constant-folding TYPE-ERRORs (in
1135 ;; #'<=) when END can be proved to be NIL, even
1136 ;; though the code is perfectly legal and safe
1137 ;; because a NIL value of END means that the
1138 ;; #'<= will never be executed.
1140 ;; Moreover, even without bug 173,
1141 ;; quite-possibly-valid code like
1142 ;; (COND ((NONINLINED-PREDICATE END)
1143 ;; (UNLESS (<= END SIZE))
1145 ;; (where NONINLINED-PREDICATE is something the
1146 ;; compiler can't do at compile time, but which
1147 ;; turns out to make the #'<= expression
1148 ;; unreachable when END=NIL) could cause errors
1149 ;; when the compiler tries to constant-fold (<=
1152 ;; So, with or without bug 173, it'd be
1153 ;; unnecessarily evil to do a full
1154 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1155 ;; from COMPILE-FILE) for legal code, so we we
1156 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1157 #'compiler-style-warn
1160 (setf (combination-kind call) :error))
1161 ((and (proper-list-of-length-p values 1))
1162 (with-ir1-environment-from-node call
1163 (let* ((lvar (node-lvar call))
1164 (prev (node-prev call))
1165 (intermediate-ctran (make-ctran)))
1166 (%delete-lvar-use call)
1167 (setf (ctran-next prev) nil)
1168 (setf (node-prev call) nil)
1169 (reference-constant prev intermediate-ctran lvar
1171 (link-node-to-previous-ctran call intermediate-ctran)
1172 (reoptimize-lvar lvar)
1173 (flush-combination call))))
1174 (t (let ((dummies (make-gensym-list (length args))))
1178 (declare (ignore ,@dummies))
1179 (values ,@(mapcar (lambda (x) `',x) values)))
1183 ;;;; local call optimization
1185 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1186 ;;; the leaf type is a function type, then just leave it alone, since
1187 ;;; TYPE is never going to be more specific than that (and
1188 ;;; TYPE-INTERSECTION would choke.)
1189 (defun propagate-to-refs (leaf type)
1190 (declare (type leaf leaf) (type ctype type))
1191 (let ((var-type (leaf-type leaf)))
1192 (unless (fun-type-p var-type)
1193 (let ((int (type-approx-intersection2 var-type type)))
1194 (when (type/= int var-type)
1195 (setf (leaf-type leaf) int)
1196 (dolist (ref (leaf-refs leaf))
1197 (derive-node-type ref (make-single-value-type int))
1198 ;; KLUDGE: LET var substitution
1199 (let* ((lvar (node-lvar ref)))
1200 (when (and lvar (combination-p (lvar-dest lvar)))
1201 (reoptimize-lvar lvar))))))
1204 ;;; Iteration variable: exactly one SETQ of the form:
1206 ;;; (let ((var initial))
1208 ;;; (setq var (+ var step))
1210 (defun maybe-infer-iteration-var-type (var initial-type)
1211 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1213 (() (null (rest sets)) :exit-if-null)
1214 (set-use (principal-lvar-use (set-value set)))
1215 (() (and (combination-p set-use)
1216 (eq (combination-kind set-use) :known)
1217 (fun-info-p (combination-fun-info set-use))
1218 (not (node-to-be-deleted-p set-use))
1219 (eq (combination-fun-source-name set-use) '+))
1221 (+-args (basic-combination-args set-use))
1222 (() (and (proper-list-of-length-p +-args 2 2)
1223 (let ((first (principal-lvar-use
1226 (eq (ref-leaf first) var))))
1228 (step-type (lvar-type (second +-args)))
1229 (set-type (lvar-type (set-value set))))
1230 (when (and (numeric-type-p initial-type)
1231 (numeric-type-p step-type)
1232 (numeric-type-equal initial-type step-type))
1233 (multiple-value-bind (low high)
1234 (cond ((csubtypep step-type (specifier-type '(real 0 *)))
1235 (values (numeric-type-low initial-type)
1236 (when (and (numeric-type-p set-type)
1237 (numeric-type-equal set-type initial-type))
1238 (numeric-type-high set-type))))
1239 ((csubtypep step-type (specifier-type '(real * 0)))
1240 (values (when (and (numeric-type-p set-type)
1241 (numeric-type-equal set-type initial-type))
1242 (numeric-type-low set-type))
1243 (numeric-type-high initial-type)))
1246 (modified-numeric-type initial-type
1249 :enumerable nil)))))
1250 (deftransform + ((x y) * * :result result)
1251 "check for iteration variable reoptimization"
1252 (let ((dest (principal-lvar-end result))
1253 (use (principal-lvar-use x)))
1254 (when (and (ref-p use)
1258 (reoptimize-lvar (set-value dest))))
1259 (give-up-ir1-transform))
1261 ;;; Figure out the type of a LET variable that has sets. We compute
1262 ;;; the union of the INITIAL-TYPE and the types of all the set
1263 ;;; values and to a PROPAGATE-TO-REFS with this type.
1264 (defun propagate-from-sets (var initial-type)
1265 (collect ((res initial-type type-union))
1266 (dolist (set (basic-var-sets var))
1267 (let ((type (lvar-type (set-value set))))
1269 (when (node-reoptimize set)
1270 (derive-node-type set (make-single-value-type type))
1271 (setf (node-reoptimize set) nil))))
1273 (awhen (maybe-infer-iteration-var-type var initial-type)
1275 (propagate-to-refs var res)))
1278 ;;; If a LET variable, find the initial value's type and do
1279 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1281 (defun ir1-optimize-set (node)
1282 (declare (type cset node))
1283 (let ((var (set-var node)))
1284 (when (and (lambda-var-p var) (leaf-refs var))
1285 (let ((home (lambda-var-home var)))
1286 (when (eq (functional-kind home) :let)
1287 (let* ((initial-value (let-var-initial-value var))
1288 (initial-type (lvar-type initial-value)))
1289 (setf (lvar-reoptimize initial-value) nil)
1290 (propagate-from-sets var initial-type))))))
1292 (derive-node-type node (make-single-value-type
1293 (lvar-type (set-value node))))
1296 ;;; Return true if the value of REF will always be the same (and is
1297 ;;; thus legal to substitute.)
1298 (defun constant-reference-p (ref)
1299 (declare (type ref ref))
1300 (let ((leaf (ref-leaf ref)))
1302 ((or constant functional) t)
1304 (null (lambda-var-sets leaf)))
1306 (not (eq (defined-fun-inlinep leaf) :notinline)))
1308 (case (global-var-kind leaf)
1310 (let ((name (leaf-source-name leaf)))
1312 (eq (symbol-package (fun-name-block-name name))
1314 (info :function :info name)))))))))
1316 ;;; If we have a non-set LET var with a single use, then (if possible)
1317 ;;; replace the variable reference's LVAR with the arg lvar.
1319 ;;; We change the REF to be a reference to NIL with unused value, and
1320 ;;; let it be flushed as dead code. A side effect of this substitution
1321 ;;; is to delete the variable.
1322 (defun substitute-single-use-lvar (arg var)
1323 (declare (type lvar arg) (type lambda-var var))
1324 (binding* ((ref (first (leaf-refs var)))
1325 (lvar (node-lvar ref) :exit-if-null)
1326 (dest (lvar-dest lvar)))
1328 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1329 ;; LVAR-USEs should not be met on one path. Another problem
1330 ;; is with dynamic-extent.
1331 (eq (lvar-uses lvar) ref)
1332 (not (block-delete-p (node-block ref)))
1334 ;; we should not change lifetime of unknown values lvars
1336 (and (type-single-value-p (lvar-derived-type arg))
1337 (multiple-value-bind (pdest pprev)
1338 (principal-lvar-end lvar)
1339 (declare (ignore pdest))
1340 (lvar-single-value-p pprev))))
1342 (or (eq (basic-combination-fun dest) lvar)
1343 (and (eq (basic-combination-kind dest) :local)
1344 (type-single-value-p (lvar-derived-type arg)))))
1346 ;; While CRETURN and EXIT nodes may be known-values,
1347 ;; they have their own complications, such as
1348 ;; substitution into CRETURN may create new tail calls.
1351 (aver (lvar-single-value-p lvar))
1353 (eq (node-home-lambda ref)
1354 (lambda-home (lambda-var-home var))))
1355 (setf (node-derived-type ref) *wild-type*)
1356 (substitute-lvar-uses lvar arg
1357 ;; Really it is (EQ (LVAR-USES LVAR) REF):
1359 (delete-lvar-use ref)
1360 (change-ref-leaf ref (find-constant nil))
1363 (reoptimize-lvar lvar)
1366 ;;; Delete a LET, removing the call and bind nodes, and warning about
1367 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1368 ;;; along right away and delete the REF and then the lambda, since we
1369 ;;; flush the FUN lvar.
1370 (defun delete-let (clambda)
1371 (declare (type clambda clambda))
1372 (aver (functional-letlike-p clambda))
1373 (note-unreferenced-vars clambda)
1374 (let ((call (let-combination clambda)))
1375 (flush-dest (basic-combination-fun call))
1377 (unlink-node (lambda-bind clambda))
1378 (setf (lambda-bind clambda) nil))
1379 (setf (functional-kind clambda) :zombie)
1380 (let ((home (lambda-home clambda)))
1381 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1384 ;;; This function is called when one of the arguments to a LET
1385 ;;; changes. We look at each changed argument. If the corresponding
1386 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1387 ;;; consider substituting for the variable, and also propagate
1388 ;;; derived-type information for the arg to all the VAR's refs.
1390 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1391 ;;; subtype of the argument's leaf type. This prevents type checking
1392 ;;; from being defeated, and also ensures that the best representation
1393 ;;; for the variable can be used.
1395 ;;; Substitution of individual references is inhibited if the
1396 ;;; reference is in a different component from the home. This can only
1397 ;;; happen with closures over top level lambda vars. In such cases,
1398 ;;; the references may have already been compiled, and thus can't be
1399 ;;; retroactively modified.
1401 ;;; If all of the variables are deleted (have no references) when we
1402 ;;; are done, then we delete the LET.
1404 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1406 (defun propagate-let-args (call fun)
1407 (declare (type combination call) (type clambda fun))
1408 (loop for arg in (combination-args call)
1409 and var in (lambda-vars fun) do
1410 (when (and arg (lvar-reoptimize arg))
1411 (setf (lvar-reoptimize arg) nil)
1413 ((lambda-var-sets var)
1414 (propagate-from-sets var (lvar-type arg)))
1415 ((let ((use (lvar-uses arg)))
1417 (let ((leaf (ref-leaf use)))
1418 (when (and (constant-reference-p use)
1419 (csubtypep (leaf-type leaf)
1420 ;; (NODE-DERIVED-TYPE USE) would
1421 ;; be better -- APD, 2003-05-15
1423 (propagate-to-refs var (lvar-type arg))
1424 (let ((use-component (node-component use)))
1425 (prog1 (substitute-leaf-if
1427 (cond ((eq (node-component ref) use-component)
1430 (aver (lambda-toplevelish-p (lambda-home fun)))
1434 ((and (null (rest (leaf-refs var)))
1435 (substitute-single-use-lvar arg var)))
1437 (propagate-to-refs var (lvar-type arg))))))
1439 (when (every #'not (combination-args call))
1444 ;;; This function is called when one of the args to a non-LET local
1445 ;;; call changes. For each changed argument corresponding to an unset
1446 ;;; variable, we compute the union of the types across all calls and
1447 ;;; propagate this type information to the var's refs.
1449 ;;; If the function has an XEP, then we don't do anything, since we
1450 ;;; won't discover anything.
1452 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1453 ;;; corresponding to changed arguments in CALL, since the only use in
1454 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1456 (defun propagate-local-call-args (call fun)
1457 (declare (type combination call) (type clambda fun))
1459 (unless (or (functional-entry-fun fun)
1460 (lambda-optional-dispatch fun))
1461 (let* ((vars (lambda-vars fun))
1462 (union (mapcar (lambda (arg var)
1464 (lvar-reoptimize arg)
1465 (null (basic-var-sets var)))
1467 (basic-combination-args call)
1469 (this-ref (lvar-use (basic-combination-fun call))))
1471 (dolist (arg (basic-combination-args call))
1473 (setf (lvar-reoptimize arg) nil)))
1475 (dolist (ref (leaf-refs fun))
1476 (let ((dest (node-dest ref)))
1477 (unless (or (eq ref this-ref) (not dest))
1479 (mapcar (lambda (this-arg old)
1481 (setf (lvar-reoptimize this-arg) nil)
1482 (type-union (lvar-type this-arg) old)))
1483 (basic-combination-args dest)
1486 (loop for var in vars
1488 when type do (propagate-to-refs var type))))
1492 ;;;; multiple values optimization
1494 ;;; Do stuff to notice a change to a MV combination node. There are
1495 ;;; two main branches here:
1496 ;;; -- If the call is local, then it is already a MV let, or should
1497 ;;; become one. Note that although all :LOCAL MV calls must eventually
1498 ;;; be converted to :MV-LETs, there can be a window when the call
1499 ;;; is local, but has not been LET converted yet. This is because
1500 ;;; the entry-point lambdas may have stray references (in other
1501 ;;; entry points) that have not been deleted yet.
1502 ;;; -- The call is full. This case is somewhat similar to the non-MV
1503 ;;; combination optimization: we propagate return type information and
1504 ;;; notice non-returning calls. We also have an optimization
1505 ;;; which tries to convert MV-CALLs into MV-binds.
1506 (defun ir1-optimize-mv-combination (node)
1507 (ecase (basic-combination-kind node)
1509 (let ((fun-lvar (basic-combination-fun node)))
1510 (when (lvar-reoptimize fun-lvar)
1511 (setf (lvar-reoptimize fun-lvar) nil)
1512 (maybe-let-convert (combination-lambda node))))
1513 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1514 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1515 (unless (convert-mv-bind-to-let node)
1516 (ir1-optimize-mv-bind node))))
1518 (let* ((fun (basic-combination-fun node))
1519 (fun-changed (lvar-reoptimize fun))
1520 (args (basic-combination-args node)))
1522 (setf (lvar-reoptimize fun) nil)
1523 (let ((type (lvar-type fun)))
1524 (when (fun-type-p type)
1525 (derive-node-type node (fun-type-returns type))))
1526 (maybe-terminate-block node nil)
1527 (let ((use (lvar-uses fun)))
1528 (when (and (ref-p use) (functional-p (ref-leaf use)))
1529 (convert-call-if-possible use node)
1530 (when (eq (basic-combination-kind node) :local)
1531 (maybe-let-convert (ref-leaf use))))))
1532 (unless (or (eq (basic-combination-kind node) :local)
1533 (eq (lvar-fun-name fun) '%throw))
1534 (ir1-optimize-mv-call node))
1536 (setf (lvar-reoptimize arg) nil))))
1540 ;;; Propagate derived type info from the values lvar to the vars.
1541 (defun ir1-optimize-mv-bind (node)
1542 (declare (type mv-combination node))
1543 (let* ((arg (first (basic-combination-args node)))
1544 (vars (lambda-vars (combination-lambda node)))
1545 (n-vars (length vars))
1546 (types (values-type-in (lvar-derived-type arg)
1548 (loop for var in vars
1550 do (if (basic-var-sets var)
1551 (propagate-from-sets var type)
1552 (propagate-to-refs var type)))
1553 (setf (lvar-reoptimize arg) nil))
1556 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1558 ;;; -- The call has only one argument, and
1559 ;;; -- The function has a known fixed number of arguments, or
1560 ;;; -- The argument yields a known fixed number of values.
1562 ;;; What we do is change the function in the MV-CALL to be a lambda
1563 ;;; that "looks like an MV bind", which allows
1564 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1565 ;;; converted (the next time around.) This new lambda just calls the
1566 ;;; actual function with the MV-BIND variables as arguments. Note that
1567 ;;; this new MV bind is not let-converted immediately, as there are
1568 ;;; going to be stray references from the entry-point functions until
1569 ;;; they get deleted.
1571 ;;; In order to avoid loss of argument count checking, we only do the
1572 ;;; transformation according to a known number of expected argument if
1573 ;;; safety is unimportant. We can always convert if we know the number
1574 ;;; of actual values, since the normal call that we build will still
1575 ;;; do any appropriate argument count checking.
1577 ;;; We only attempt the transformation if the called function is a
1578 ;;; constant reference. This allows us to just splice the leaf into
1579 ;;; the new function, instead of trying to somehow bind the function
1580 ;;; expression. The leaf must be constant because we are evaluating it
1581 ;;; again in a different place. This also has the effect of squelching
1582 ;;; multiple warnings when there is an argument count error.
1583 (defun ir1-optimize-mv-call (node)
1584 (let ((fun (basic-combination-fun node))
1585 (*compiler-error-context* node)
1586 (ref (lvar-uses (basic-combination-fun node)))
1587 (args (basic-combination-args node)))
1589 (unless (and (ref-p ref) (constant-reference-p ref)
1591 (return-from ir1-optimize-mv-call))
1593 (multiple-value-bind (min max)
1594 (fun-type-nargs (lvar-type fun))
1596 (multiple-value-bind (types nvals)
1597 (values-types (lvar-derived-type (first args)))
1598 (declare (ignore types))
1599 (if (eq nvals :unknown) nil nvals))))
1602 (when (and min (< total-nvals min))
1604 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1607 (setf (basic-combination-kind node) :error)
1608 (return-from ir1-optimize-mv-call))
1609 (when (and max (> total-nvals max))
1611 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1614 (setf (basic-combination-kind node) :error)
1615 (return-from ir1-optimize-mv-call)))
1617 (let ((count (cond (total-nvals)
1618 ((and (policy node (zerop verify-arg-count))
1623 (with-ir1-environment-from-node node
1624 (let* ((dums (make-gensym-list count))
1626 (fun (ir1-convert-lambda
1627 `(lambda (&optional ,@dums &rest ,ignore)
1628 (declare (ignore ,ignore))
1629 (funcall ,(ref-leaf ref) ,@dums)))))
1630 (change-ref-leaf ref fun)
1631 (aver (eq (basic-combination-kind node) :full))
1632 (locall-analyze-component *current-component*)
1633 (aver (eq (basic-combination-kind node) :local)))))))))
1637 ;;; (multiple-value-bind
1646 ;;; What we actually do is convert the VALUES combination into a
1647 ;;; normal LET combination calling the original :MV-LET lambda. If
1648 ;;; there are extra args to VALUES, discard the corresponding
1649 ;;; lvars. If there are insufficient args, insert references to NIL.
1650 (defun convert-mv-bind-to-let (call)
1651 (declare (type mv-combination call))
1652 (let* ((arg (first (basic-combination-args call)))
1653 (use (lvar-uses arg)))
1654 (when (and (combination-p use)
1655 (eq (lvar-fun-name (combination-fun use))
1657 (let* ((fun (combination-lambda call))
1658 (vars (lambda-vars fun))
1659 (vals (combination-args use))
1660 (nvars (length vars))
1661 (nvals (length vals)))
1662 (cond ((> nvals nvars)
1663 (mapc #'flush-dest (subseq vals nvars))
1664 (setq vals (subseq vals 0 nvars)))
1666 (with-ir1-environment-from-node use
1667 (let ((node-prev (node-prev use)))
1668 (setf (node-prev use) nil)
1669 (setf (ctran-next node-prev) nil)
1670 (collect ((res vals))
1671 (loop for count below (- nvars nvals)
1672 for prev = node-prev then ctran
1673 for ctran = (make-ctran)
1674 and lvar = (make-lvar use)
1675 do (reference-constant prev ctran lvar nil)
1677 finally (link-node-to-previous-ctran
1679 (setq vals (res)))))))
1680 (setf (combination-args use) vals)
1681 (flush-dest (combination-fun use))
1682 (let ((fun-lvar (basic-combination-fun call)))
1683 (setf (lvar-dest fun-lvar) use)
1684 (setf (combination-fun use) fun-lvar)
1685 (flush-lvar-externally-checkable-type fun-lvar))
1686 (setf (combination-kind use) :local)
1687 (setf (functional-kind fun) :let)
1688 (flush-dest (first (basic-combination-args call)))
1691 (reoptimize-lvar (first vals)))
1692 (propagate-to-args use fun)
1693 (reoptimize-call use))
1697 ;;; (values-list (list x y z))
1702 ;;; In implementation, this is somewhat similar to
1703 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1704 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1705 ;;; (allowing the LIST to be flushed.)
1707 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1708 (defoptimizer (values-list optimizer) ((list) node)
1709 (let ((use (lvar-uses list)))
1710 (when (and (combination-p use)
1711 (eq (lvar-fun-name (combination-fun use))
1714 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1715 (change-ref-leaf (lvar-uses (combination-fun node))
1716 (find-free-fun 'values "in a strange place"))
1717 (setf (combination-kind node) :full)
1718 (let ((args (combination-args use)))
1720 (setf (lvar-dest arg) node)
1721 (flush-lvar-externally-checkable-type arg))
1722 (setf (combination-args use) nil)
1724 (setf (combination-args node) args))
1727 ;;; If VALUES appears in a non-MV context, then effectively convert it
1728 ;;; to a PROG1. This allows the computation of the additional values
1729 ;;; to become dead code.
1730 (deftransform values ((&rest vals) * * :node node)
1731 (unless (lvar-single-value-p (node-lvar node))
1732 (give-up-ir1-transform))
1733 (setf (node-derived-type node)
1734 (make-short-values-type (list (single-value-type
1735 (node-derived-type node)))))
1736 (principal-lvar-single-valuify (node-lvar node))
1738 (let ((dummies (make-gensym-list (length (cdr vals)))))
1739 `(lambda (val ,@dummies)
1740 (declare (ignore ,@dummies))
1746 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1747 (declare (type cast cast))
1748 (let ((value (cast-value cast))
1749 (atype (cast-asserted-type cast)))
1750 (when (not do-not-optimize)
1751 (let ((lvar (node-lvar cast)))
1752 (when (values-subtypep (lvar-derived-type value)
1753 (cast-asserted-type cast))
1754 (delete-filter cast lvar value)
1756 (reoptimize-lvar lvar)
1757 (when (lvar-single-value-p lvar)
1758 (note-single-valuified-lvar lvar)))
1759 (return-from ir1-optimize-cast t))
1761 (when (and (listp (lvar-uses value))
1763 ;; Pathwise removing of CAST
1764 (let ((ctran (node-next cast))
1765 (dest (lvar-dest lvar))
1768 (do-uses (use value)
1769 (when (and (values-subtypep (node-derived-type use) atype)
1770 (immediately-used-p value use))
1772 (when ctran (ensure-block-start ctran))
1773 (setq next-block (first (block-succ (node-block cast))))
1774 (ensure-block-start (node-prev cast))
1775 (reoptimize-lvar lvar)
1776 (setf (lvar-%derived-type value) nil))
1777 (%delete-lvar-use use)
1778 (add-lvar-use use lvar)
1779 (unlink-blocks (node-block use) (node-block cast))
1780 (link-blocks (node-block use) next-block)
1781 (when (and (return-p dest)
1782 (basic-combination-p use)
1783 (eq (basic-combination-kind use) :local))
1785 (dolist (use (merges))
1786 (merge-tail-sets use)))))))
1788 (let* ((value-type (lvar-derived-type value))
1789 (int (values-type-intersection value-type atype)))
1790 (derive-node-type cast int)
1791 (when (eq int *empty-type*)
1792 (unless (eq value-type *empty-type*)
1794 ;; FIXME: Do it in one step.
1797 (if (cast-single-value-p cast)
1799 `(multiple-value-call #'list 'dummy)))
1802 ;; FIXME: Derived type.
1803 `(%compile-time-type-error 'dummy
1804 ',(type-specifier atype)
1805 ',(type-specifier value-type)))
1806 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1807 ;; functions, so we declare the return type of
1808 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1810 (setq value (cast-value cast))
1811 (derive-node-type (lvar-uses value) *empty-type*)
1812 (maybe-terminate-block (lvar-uses value) nil)
1813 ;; FIXME: Is it necessary?
1814 (aver (null (block-pred (node-block cast))))
1815 (delete-block-lazily (node-block cast))
1816 (return-from ir1-optimize-cast)))
1817 (when (eq (node-derived-type cast) *empty-type*)
1818 (maybe-terminate-block cast nil))
1820 (when (and (cast-%type-check cast)
1821 (values-subtypep value-type
1822 (cast-type-to-check cast)))
1823 (setf (cast-%type-check cast) nil))))
1825 (unless do-not-optimize
1826 (setf (node-reoptimize cast) nil)))