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 ;;; This function is called by optimizers to indicate that something
111 ;;; interesting has happened to the value of LVAR. Optimizers must
112 ;;; make sure that they don't call for reoptimization when nothing has
113 ;;; happened, since optimization will fail to terminate.
115 ;;; We clear any cached type for the lvar and set the reoptimize flags
116 ;;; on everything in sight.
117 (defun reoptimize-lvar (lvar)
118 (declare (type (or lvar null) lvar))
120 (setf (lvar-%derived-type lvar) nil)
121 (let ((dest (lvar-dest lvar)))
123 (setf (lvar-reoptimize lvar) t)
124 (setf (node-reoptimize dest) t)
125 (binding* (;; Since this may be called during IR1 conversion,
126 ;; PREV may be missing.
127 (prev (node-prev dest) :exit-if-null)
128 (block (ctran-block prev))
129 (component (block-component block)))
130 (when (typep dest 'cif)
131 (setf (block-test-modified block) t))
132 (setf (block-reoptimize block) t)
133 (setf (component-reoptimize component) t))))
135 (setf (block-type-check (node-block node)) t)))
138 (defun reoptimize-lvar-uses (lvar)
139 (declare (type lvar lvar))
141 (setf (node-reoptimize use) t)
142 (setf (block-reoptimize (node-block use)) t)
143 (setf (component-reoptimize (node-component use)) t)))
145 ;;; Annotate NODE to indicate that its result has been proven to be
146 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
147 ;;; only correct way to supply information discovered about a node's
148 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
149 ;;; information may be lost and reoptimization may not happen.
151 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
152 ;;; intersection is different from the old type, then we do a
153 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
154 (defun derive-node-type (node rtype)
155 (declare (type valued-node node) (type ctype rtype))
156 (let ((node-type (node-derived-type node)))
157 (unless (eq node-type rtype)
158 (let ((int (values-type-intersection node-type rtype))
159 (lvar (node-lvar node)))
160 (when (type/= node-type int)
161 (when (and *check-consistency*
162 (eq int *empty-type*)
163 (not (eq rtype *empty-type*)))
164 (let ((*compiler-error-context* node))
166 "New inferred type ~S conflicts with old type:~
167 ~% ~S~%*** possible internal error? Please report this."
168 (type-specifier rtype) (type-specifier node-type))))
169 (setf (node-derived-type node) int)
170 ;; If the new type consists of only one object, replace the
171 ;; node with a constant reference.
172 (when (and (ref-p node)
173 (lambda-var-p (ref-leaf node)))
174 (let ((type (single-value-type int)))
175 (when (and (member-type-p type)
176 (null (rest (member-type-members type))))
177 (change-ref-leaf node (find-constant
178 (first (member-type-members type)))))))
179 (reoptimize-lvar lvar)))))
182 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
183 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
184 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
185 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
186 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
187 (defun assert-lvar-type (lvar type policy)
188 (declare (type lvar lvar) (type ctype type))
189 (unless (values-subtypep (lvar-derived-type lvar) type)
190 (let* ((dest (lvar-dest lvar))
191 (ctran (node-prev dest)))
192 (with-ir1-environment-from-node dest
193 (let* ((cast (make-cast lvar type policy))
194 (internal-lvar (make-lvar))
195 (internal-ctran (make-ctran)))
196 (setf (ctran-next ctran) cast
197 (node-prev cast) ctran)
198 (use-continuation cast internal-ctran internal-lvar)
199 (link-node-to-previous-ctran dest internal-ctran)
200 (substitute-lvar internal-lvar lvar)
201 (setf (lvar-dest lvar) cast)
202 (reoptimize-lvar lvar)
203 (when (return-p dest)
204 (node-ends-block cast))
205 (setf (block-attributep (block-flags (node-block cast))
206 type-check type-asserted)
212 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
213 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
214 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
215 ;;; we are done, then another iteration would be beneficial.
216 (defun ir1-optimize (component)
217 (declare (type component component))
218 (setf (component-reoptimize component) nil)
219 (loop with block = (block-next (component-head component))
220 with tail = (component-tail component)
221 for last-block = block
222 until (eq block tail)
224 ;; We delete blocks when there is either no predecessor or the
225 ;; block is in a lambda that has been deleted. These blocks
226 ;; would eventually be deleted by DFO recomputation, but doing
227 ;; it here immediately makes the effect available to IR1
229 ((or (block-delete-p block)
230 (null (block-pred block)))
231 (delete-block-lazily block)
232 (setq block (clean-component component block)))
233 ((eq (functional-kind (block-home-lambda block)) :deleted)
234 ;; Preserve the BLOCK-SUCC invariant that almost every block has
235 ;; one successor (and a block with DELETE-P set is an acceptable
237 (mark-for-deletion block)
238 (setq block (clean-component component block)))
241 (let ((succ (block-succ block)))
242 (unless (singleton-p succ)
245 (let ((last (block-last block)))
248 (flush-dest (if-test last))
249 (when (unlink-node last)
252 (when (maybe-delete-exit last)
255 (unless (join-successor-if-possible block)
258 (when (and (block-reoptimize block) (block-component block))
259 (aver (not (block-delete-p block)))
260 (ir1-optimize-block block))
262 (cond ((and (block-delete-p block) (block-component block))
263 (setq block (clean-component component block)))
264 ((and (block-flush-p block) (block-component block))
265 (flush-dead-code block)))))
266 do (when (eq block last-block)
267 (setq block (block-next block))))
271 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
274 ;;; Note that although they are cleared here, REOPTIMIZE flags might
275 ;;; still be set upon return from this function, meaning that further
276 ;;; optimization is wanted (as a consequence of optimizations we did).
277 (defun ir1-optimize-block (block)
278 (declare (type cblock block))
279 ;; We clear the node and block REOPTIMIZE flags before doing the
280 ;; optimization, not after. This ensures that the node or block will
281 ;; be reoptimized if necessary.
282 (setf (block-reoptimize block) nil)
283 (do-nodes (node nil block :restart-p t)
284 (when (node-reoptimize node)
285 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
286 (setf (node-reoptimize node) nil)
290 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
291 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
292 ;; any argument changes.
293 (ir1-optimize-combination node))
295 (ir1-optimize-if node))
297 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
298 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
299 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
301 (setf (node-reoptimize node) t)
302 (ir1-optimize-return node))
304 (ir1-optimize-mv-combination node))
306 ;; With an EXIT, we derive the node's type from the VALUE's
308 (let ((value (exit-value node)))
310 (derive-node-type node (lvar-derived-type value)))))
312 (ir1-optimize-set node))
314 (ir1-optimize-cast node)))))
318 ;;; Try to join with a successor block. If we succeed, we return true,
320 (defun join-successor-if-possible (block)
321 (declare (type cblock block))
322 (let ((next (first (block-succ block))))
323 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
324 (cond ( ;; We cannot combine with a successor block if:
326 ;; the successor has more than one predecessor;
327 (rest (block-pred next))
328 ;; the successor is the current block (infinite loop);
330 ;; the next block has a different cleanup, and thus
331 ;; we may want to insert cleanup code between the
332 ;; two blocks at some point;
333 (not (eq (block-end-cleanup block)
334 (block-start-cleanup next)))
335 ;; the next block has a different home lambda, and
336 ;; thus the control transfer is a non-local exit.
337 (not (eq (block-home-lambda block)
338 (block-home-lambda next)))
339 ;; Stack analysis phase wants ENTRY to start a block...
340 (entry-p (block-start-node next))
341 (let ((last (block-last block)))
342 (and (valued-node-p last)
343 (awhen (node-lvar last)
345 ;; ... and a DX-allocator to end a block.
346 (lvar-dynamic-extent it)
347 ;; FIXME: This is a partial workaround for bug 303.
348 (consp (lvar-uses it)))))))
351 (join-blocks block next)
354 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
355 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
356 ;;; for the two blocks so that any indicated optimization gets done.
357 (defun join-blocks (block1 block2)
358 (declare (type cblock block1 block2))
359 (let* ((last1 (block-last block1))
360 (last2 (block-last block2))
361 (succ (block-succ block2))
362 (start2 (block-start block2)))
363 (do ((ctran start2 (node-next (ctran-next ctran))))
365 (setf (ctran-block ctran) block1))
367 (unlink-blocks block1 block2)
369 (unlink-blocks block2 block)
370 (link-blocks block1 block))
372 (setf (ctran-kind start2) :inside-block)
373 (setf (node-next last1) start2)
374 (setf (ctran-use start2) last1)
375 (setf (block-last block1) last2))
377 (setf (block-flags block1)
378 (attributes-union (block-flags block1)
380 (block-attributes type-asserted test-modified)))
382 (let ((next (block-next block2))
383 (prev (block-prev block2)))
384 (setf (block-next prev) next)
385 (setf (block-prev next) prev))
389 ;;; Delete any nodes in BLOCK whose value is unused and which have no
390 ;;; side effects. We can delete sets of lexical variables when the set
391 ;;; variable has no references.
392 (defun flush-dead-code (block)
393 (declare (type cblock block))
394 (setf (block-flush-p block) nil)
395 (do-nodes-backwards (node lvar block :restart-p t)
402 (let ((kind (combination-kind node))
403 (info (combination-fun-info node)))
404 (when (and (eq kind :known) (fun-info-p info))
405 (let ((attr (fun-info-attributes info)))
406 (when (and (not (ir1-attributep attr call))
407 ;; ### For now, don't delete potentially
408 ;; flushable calls when they have the CALL
409 ;; attribute. Someday we should look at the
410 ;; functional args to determine if they have
412 (if (policy node (= safety 3))
413 (ir1-attributep attr flushable)
414 (ir1-attributep attr unsafely-flushable)))
415 (flush-combination node))))))
417 (when (eq (basic-combination-kind node) :local)
418 (let ((fun (combination-lambda node)))
419 (when (dolist (var (lambda-vars fun) t)
420 (when (or (leaf-refs var)
421 (lambda-var-sets var))
423 (flush-dest (first (basic-combination-args node)))
426 (let ((value (exit-value node)))
429 (setf (exit-value node) nil))))
431 (let ((var (set-var node)))
432 (when (and (lambda-var-p var)
433 (null (leaf-refs var)))
434 (flush-dest (set-value node))
435 (setf (basic-var-sets var)
436 (delq node (basic-var-sets var)))
437 (unlink-node node))))
439 (unless (cast-type-check node)
440 (flush-dest (cast-value node))
441 (unlink-node node))))))
445 ;;;; local call return type propagation
447 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
448 ;;; flag set. It iterates over the uses of the RESULT, looking for
449 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
450 ;;; call, then we union its type together with the types of other such
451 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
452 ;;; type with the RESULT's asserted type. We can make this
453 ;;; intersection now (potentially before type checking) because this
454 ;;; assertion on the result will eventually be checked (if
457 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
458 ;;; combination, which may change the succesor of the call to be the
459 ;;; called function, and if so, checks if the call can become an
460 ;;; assignment. If we convert to an assignment, we abort, since the
461 ;;; RETURN has been deleted.
462 (defun find-result-type (node)
463 (declare (type creturn node))
464 (let ((result (return-result node)))
465 (collect ((use-union *empty-type* values-type-union))
466 (do-uses (use result)
467 (let ((use-home (node-home-lambda use)))
468 (cond ((or (eq (functional-kind use-home) :deleted)
469 (block-delete-p (node-block use))))
470 ((and (basic-combination-p use)
471 (eq (basic-combination-kind use) :local))
472 (aver (eq (lambda-tail-set use-home)
473 (lambda-tail-set (combination-lambda use))))
474 (when (combination-p use)
475 (when (nth-value 1 (maybe-convert-tail-local-call use))
476 (return-from find-result-type t))))
478 (use-union (node-derived-type use))))))
480 ;; (values-type-intersection
481 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
485 (setf (return-result-type node) int))))
488 ;;; Do stuff to realize that something has changed about the value
489 ;;; delivered to a return node. Since we consider the return values of
490 ;;; all functions in the tail set to be equivalent, this amounts to
491 ;;; bringing the entire tail set up to date. We iterate over the
492 ;;; returns for all the functions in the tail set, reanalyzing them
493 ;;; all (not treating NODE specially.)
495 ;;; When we are done, we check whether the new type is different from
496 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
497 ;;; all the lvars for references to functions in the tail set. This
498 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
499 ;;; results of the calls.
500 (defun ir1-optimize-return (node)
501 (declare (type creturn node))
504 (let* ((tails (lambda-tail-set (return-lambda node)))
505 (funs (tail-set-funs tails)))
506 (collect ((res *empty-type* values-type-union))
508 (let ((return (lambda-return fun)))
510 (when (node-reoptimize return)
511 (setf (node-reoptimize return) nil)
512 (when (find-result-type return)
514 (res (return-result-type return)))))
516 (when (type/= (res) (tail-set-type tails))
517 (setf (tail-set-type tails) (res))
518 (dolist (fun (tail-set-funs tails))
519 (dolist (ref (leaf-refs fun))
520 (reoptimize-lvar (node-lvar ref))))))))
526 ;;; If the test has multiple uses, replicate the node when possible.
527 ;;; Also check whether the predicate is known to be true or false,
528 ;;; deleting the IF node in favor of the appropriate branch when this
530 (defun ir1-optimize-if (node)
531 (declare (type cif node))
532 (let ((test (if-test node))
533 (block (node-block node)))
535 (when (and (eq (block-start-node block) node)
536 (listp (lvar-uses test)))
538 (when (immediately-used-p test use)
539 (convert-if-if use node)
540 (when (not (listp (lvar-uses test))) (return)))))
542 (let* ((type (lvar-type test))
544 (cond ((constant-lvar-p test)
545 (if (lvar-value test)
546 (if-alternative node)
547 (if-consequent node)))
548 ((not (types-equal-or-intersect type (specifier-type 'null)))
549 (if-alternative node))
550 ((type= type (specifier-type 'null))
551 (if-consequent node)))))
554 (when (rest (block-succ block))
555 (unlink-blocks block victim))
556 (setf (component-reanalyze (node-component node)) t)
557 (unlink-node node))))
560 ;;; Create a new copy of an IF node that tests the value of the node
561 ;;; USE. The test must have >1 use, and must be immediately used by
562 ;;; USE. NODE must be the only node in its block (implying that
563 ;;; block-start = if-test).
565 ;;; This optimization has an effect semantically similar to the
566 ;;; source-to-source transformation:
567 ;;; (IF (IF A B C) D E) ==>
568 ;;; (IF A (IF B D E) (IF C D E))
570 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
571 ;;; node so that dead code deletion notes will definitely not consider
572 ;;; either node to be part of the original source. One node might
573 ;;; become unreachable, resulting in a spurious note.
574 (defun convert-if-if (use node)
575 (declare (type node use) (type cif node))
576 (with-ir1-environment-from-node node
577 (let* ((block (node-block node))
578 (test (if-test node))
579 (cblock (if-consequent node))
580 (ablock (if-alternative node))
581 (use-block (node-block use))
582 (new-ctran (make-ctran))
583 (new-lvar (make-lvar))
584 (new-node (make-if :test new-lvar
586 :alternative ablock))
587 (new-block (ctran-starts-block new-ctran)))
588 (link-node-to-previous-ctran new-node new-ctran)
589 (setf (lvar-dest new-lvar) new-node)
590 (setf (block-last new-block) new-node)
592 (unlink-blocks use-block block)
593 (%delete-lvar-use use)
594 (add-lvar-use use new-lvar)
595 (link-blocks use-block new-block)
597 (link-blocks new-block cblock)
598 (link-blocks new-block ablock)
600 (push "<IF Duplication>" (node-source-path node))
601 (push "<IF Duplication>" (node-source-path new-node))
603 (reoptimize-lvar test)
604 (reoptimize-lvar new-lvar)
605 (setf (component-reanalyze *current-component*) t)))
608 ;;;; exit IR1 optimization
610 ;;; This function attempts to delete an exit node, returning true if
611 ;;; it deletes the block as a consequence:
612 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
613 ;;; anything, since there is nothing to be done.
614 ;;; -- If the exit node and its ENTRY have the same home lambda then
615 ;;; we know the exit is local, and can delete the exit. We change
616 ;;; uses of the Exit-Value to be uses of the original lvar,
617 ;;; then unlink the node. If the exit is to a TR context, then we
618 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
619 ;;; their value to this exit.
620 ;;; -- If there is no value (as in a GO), then we skip the value
623 ;;; This function is also called by environment analysis, since it
624 ;;; wants all exits to be optimized even if normal optimization was
626 (defun maybe-delete-exit (node)
627 (declare (type exit node))
628 (let ((value (exit-value node))
629 (entry (exit-entry node)))
631 (eq (node-home-lambda node) (node-home-lambda entry)))
632 (setf (entry-exits entry) (delq node (entry-exits entry)))
634 (delete-filter node (node-lvar node) value)
635 (unlink-node node)))))
638 ;;;; combination IR1 optimization
640 ;;; Report as we try each transform?
642 (defvar *show-transforms-p* nil)
644 ;;; Do IR1 optimizations on a COMBINATION node.
645 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
646 (defun ir1-optimize-combination (node)
647 (when (lvar-reoptimize (basic-combination-fun node))
648 (propagate-fun-change node)
649 (maybe-terminate-block node nil))
650 (let ((args (basic-combination-args node))
651 (kind (basic-combination-kind node))
652 (info (basic-combination-fun-info node)))
655 (let ((fun (combination-lambda node)))
656 (if (eq (functional-kind fun) :let)
657 (propagate-let-args node fun)
658 (propagate-local-call-args node fun))))
662 (setf (lvar-reoptimize arg) nil))))
666 (setf (lvar-reoptimize arg) nil)))
668 (let ((fun (fun-info-derive-type info)))
670 (let ((res (funcall fun node)))
672 (derive-node-type node (coerce-to-values res))
673 (maybe-terminate-block node nil)))))))
678 (setf (lvar-reoptimize arg) nil)))
680 (let ((attr (fun-info-attributes info)))
681 (when (and (ir1-attributep attr foldable)
682 ;; KLUDGE: The next test could be made more sensitive,
683 ;; only suppressing constant-folding of functions with
684 ;; CALL attributes when they're actually passed
685 ;; function arguments. -- WHN 19990918
686 (not (ir1-attributep attr call))
687 (every #'constant-lvar-p args)
689 ;; Even if the function is foldable in principle,
690 ;; it might be one of our low-level
691 ;; implementation-specific functions. Such
692 ;; functions don't necessarily exist at runtime on
693 ;; a plain vanilla ANSI Common Lisp
694 ;; cross-compilation host, in which case the
695 ;; cross-compiler can't fold it because the
696 ;; cross-compiler doesn't know how to evaluate it.
698 (or (fboundp (combination-fun-source-name node))
699 (progn (format t ";;; !!! Unbound fun: (~S~{ ~S~})~%"
700 (combination-fun-source-name node)
701 (mapcar #'lvar-value args))
703 (constant-fold-call node)
704 (return-from ir1-optimize-combination)))
706 (let ((fun (fun-info-derive-type info)))
708 (let ((res (funcall fun node)))
710 (derive-node-type node (coerce-to-values res))
711 (maybe-terminate-block node nil)))))
713 (let ((fun (fun-info-optimizer info)))
714 (unless (and fun (funcall fun node))
715 (dolist (x (fun-info-transforms info))
717 (when *show-transforms-p*
718 (let* ((lvar (basic-combination-fun node))
719 (fname (lvar-fun-name lvar t)))
720 (/show "trying transform" x (transform-function x) "for" fname)))
721 (unless (ir1-transform node x)
723 (when *show-transforms-p*
724 (/show "quitting because IR1-TRANSFORM result was NIL"))
729 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
730 ;;; the block there, and link it to the component tail.
732 ;;; Except when called during IR1 convertion, we delete the
733 ;;; continuation if it has no other uses. (If it does have other uses,
736 ;;; Termination on the basis of a continuation type is
738 ;;; -- The continuation is deleted (hence the assertion is spurious), or
739 ;;; -- We are in IR1 conversion (where THE assertions are subject to
740 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
741 ;;; uses can(?) be added later. -- APD, 2003-07-17
743 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
744 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
745 (declare (type (or basic-combination cast) node))
746 (let* ((block (node-block node))
747 (lvar (node-lvar node))
748 (ctran (node-next node))
749 (tail (component-tail (block-component block)))
750 (succ (first (block-succ block))))
751 (declare (ignore lvar))
752 (unless (or (and (eq node (block-last block)) (eq succ tail))
753 (block-delete-p block))
754 (when (eq (node-derived-type node) *empty-type*)
755 (cond (ir1-converting-not-optimizing-p
758 (aver (eq (block-last block) node)))
760 (setf (block-last block) node)
761 (setf (ctran-use ctran) nil)
762 (setf (ctran-kind ctran) :unused)
763 (setf (ctran-block ctran) nil)
764 (setf (node-next node) nil)
765 (link-blocks block (ctran-starts-block ctran)))))
767 (node-ends-block node)))
769 (unlink-blocks block (first (block-succ block)))
770 (setf (component-reanalyze (block-component block)) t)
771 (aver (not (block-succ block)))
772 (link-blocks block tail)
773 (if ir1-converting-not-optimizing-p
774 (%delete-lvar-use node)
775 (delete-lvar-use node))
778 ;;; This is called both by IR1 conversion and IR1 optimization when
779 ;;; they have verified the type signature for the call, and are
780 ;;; wondering if something should be done to special-case the call. If
781 ;;; CALL is a call to a global function, then see whether it defined
783 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
784 ;;; the expansion and change the call to call it. Expansion is
785 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
786 ;;; true, we never expand, since this function has already been
787 ;;; converted. Local call analysis will duplicate the definition
788 ;;; if necessary. We claim that the parent form is LABELS for
789 ;;; context declarations, since we don't want it to be considered
790 ;;; a real global function.
791 ;;; -- If it is a known function, mark it as such by setting the KIND.
793 ;;; We return the leaf referenced (NIL if not a leaf) and the
794 ;;; FUN-INFO assigned.
795 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
796 (declare (type combination call))
797 (let* ((ref (lvar-uses (basic-combination-fun call)))
798 (leaf (when (ref-p ref) (ref-leaf ref)))
799 (inlinep (if (defined-fun-p leaf)
800 (defined-fun-inlinep leaf)
803 ((eq inlinep :notinline)
804 (let ((info (info :function :info (leaf-source-name leaf))))
806 (setf (basic-combination-fun-info call) info))
808 ((not (and (global-var-p leaf)
809 (eq (global-var-kind leaf) :global-function)))
814 ((nil :maybe-inline) (policy call (zerop space))))
816 (defined-fun-inline-expansion leaf)
817 (let ((fun (defined-fun-functional leaf)))
819 (and (eq inlinep :inline) (functional-kind fun))))
820 (inline-expansion-ok call))
821 (flet (;; FIXME: Is this what the old CMU CL internal documentation
822 ;; called semi-inlining? A more descriptive name would
823 ;; be nice. -- WHN 2002-01-07
825 (let ((res (let ((*allow-instrumenting* t))
826 (ir1-convert-lambda-for-defun
827 (defined-fun-inline-expansion leaf)
829 #'ir1-convert-inline-lambda))))
830 (setf (defined-fun-functional leaf) res)
831 (change-ref-leaf ref res))))
832 (if ir1-converting-not-optimizing-p
834 (with-ir1-environment-from-node call
836 (locall-analyze-component *current-component*))))
838 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
841 (let ((info (info :function :info (leaf-source-name leaf))))
845 (setf (basic-combination-kind call) :known)
846 (setf (basic-combination-fun-info call) info)))
847 (values leaf nil)))))))
849 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
850 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
851 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
852 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
853 ;;; syntax check, arg/result type processing, but still call
854 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
855 ;;; and that checking is done by local call analysis.
856 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
857 (declare (type combination call) (type ctype type))
858 (cond ((not (fun-type-p type))
859 (aver (multiple-value-bind (val win)
860 (csubtypep type (specifier-type 'function))
862 (recognize-known-call call ir1-converting-not-optimizing-p))
863 ((valid-fun-use call type
864 :argument-test #'always-subtypep
866 ;; KLUDGE: Common Lisp is such a dynamic
867 ;; language that all we can do here in
868 ;; general is issue a STYLE-WARNING. It
869 ;; would be nice to issue a full WARNING
870 ;; in the special case of of type
871 ;; mismatches within a compilation unit
872 ;; (as in section 3.2.2.3 of the spec)
873 ;; but at least as of sbcl-0.6.11, we
874 ;; don't keep track of whether the
875 ;; mismatched data came from the same
876 ;; compilation unit, so we can't do that.
879 ;; FIXME: Actually, I think we could
880 ;; issue a full WARNING if the call
881 ;; violates a DECLAIM FTYPE.
882 :lossage-fun #'compiler-style-warn
883 :unwinnage-fun #'compiler-notify)
884 (assert-call-type call type)
885 (maybe-terminate-block call ir1-converting-not-optimizing-p)
886 (recognize-known-call call ir1-converting-not-optimizing-p))
888 (setf (combination-kind call) :error)
891 ;;; This is called by IR1-OPTIMIZE when the function for a call has
892 ;;; changed. If the call is local, we try to LET-convert it, and
893 ;;; derive the result type. If it is a :FULL call, we validate it
894 ;;; against the type, which recognizes known calls, does inline
895 ;;; expansion, etc. If a call to a predicate in a non-conditional
896 ;;; position or to a function with a source transform, then we
897 ;;; reconvert the form to give IR1 another chance.
898 (defun propagate-fun-change (call)
899 (declare (type combination call))
900 (let ((*compiler-error-context* call)
901 (fun-lvar (basic-combination-fun call)))
902 (setf (lvar-reoptimize fun-lvar) nil)
903 (case (combination-kind call)
905 (let ((fun (combination-lambda call)))
906 (maybe-let-convert fun)
907 (unless (member (functional-kind fun) '(:let :assignment :deleted))
908 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
910 (multiple-value-bind (leaf info)
911 (validate-call-type call (lvar-type fun-lvar) nil)
912 (cond ((functional-p leaf)
913 (convert-call-if-possible
914 (lvar-uses (basic-combination-fun call))
917 ((and (global-var-p leaf)
918 (eq (global-var-kind leaf) :global-function)
919 (leaf-has-source-name-p leaf)
920 (or (info :function :source-transform (leaf-source-name leaf))
922 (ir1-attributep (fun-info-attributes info)
924 (let ((lvar (node-lvar call)))
925 (and lvar (not (if-p (lvar-dest lvar))))))))
926 (let ((name (leaf-source-name leaf))
927 (dummies (make-gensym-list
928 (length (combination-args call)))))
931 (,@(if (symbolp name)
935 (leaf-source-name leaf)))))))))
938 ;;;; known function optimization
940 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
941 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
942 ;;; replace it, otherwise add a new one.
943 (defun record-optimization-failure (node transform args)
944 (declare (type combination node) (type transform transform)
945 (type (or fun-type list) args))
946 (let* ((table (component-failed-optimizations *component-being-compiled*))
947 (found (assoc transform (gethash node table))))
949 (setf (cdr found) args)
950 (push (cons transform args) (gethash node table))))
953 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
954 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
955 ;;; doing the transform for some reason and FLAME is true, then we
956 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
957 ;;; finalize to pick up. We return true if the transform failed, and
958 ;;; thus further transformation should be attempted. We return false
959 ;;; if either the transform succeeded or was aborted.
960 (defun ir1-transform (node transform)
961 (declare (type combination node) (type transform transform))
962 (let* ((type (transform-type transform))
963 (fun (transform-function transform))
964 (constrained (fun-type-p type))
965 (table (component-failed-optimizations *component-being-compiled*))
966 (flame (if (transform-important transform)
967 (policy node (>= speed inhibit-warnings))
968 (policy node (> speed inhibit-warnings))))
969 (*compiler-error-context* node))
970 (cond ((or (not constrained)
971 (valid-fun-use node type))
972 (multiple-value-bind (severity args)
973 (catch 'give-up-ir1-transform
976 (combination-fun-source-name node))
983 (setf (combination-kind node) :error)
991 (record-optimization-failure node transform args))
992 (setf (gethash node table)
993 (remove transform (gethash node table) :key #'car)))
1001 :argument-test #'types-equal-or-intersect
1002 :result-test #'values-types-equal-or-intersect))
1003 (record-optimization-failure node transform type)
1008 ;;; When we don't like an IR1 transform, we throw the severity/reason
1011 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1012 ;;; aborting this attempt to transform the call, but admitting the
1013 ;;; possibility that this or some other transform will later succeed.
1014 ;;; If arguments are supplied, they are format arguments for an
1015 ;;; efficiency note.
1017 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1018 ;;; force a normal call to the function at run time. No further
1019 ;;; optimizations will be attempted.
1021 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1022 ;;; delay the transform on the node until later. REASONS specifies
1023 ;;; when the transform will be later retried. The :OPTIMIZE reason
1024 ;;; causes the transform to be delayed until after the current IR1
1025 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1026 ;;; be delayed until after constraint propagation.
1028 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1029 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1030 ;;; do CASE operations on the various REASON values, it might be a
1031 ;;; good idea to go OO, representing the reasons by objects, using
1032 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1033 ;;; SIGNAL instead of THROW.
1034 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1035 (defun give-up-ir1-transform (&rest args)
1036 (throw 'give-up-ir1-transform (values :failure args)))
1037 (defun abort-ir1-transform (&rest args)
1038 (throw 'give-up-ir1-transform (values :aborted args)))
1039 (defun delay-ir1-transform (node &rest reasons)
1040 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1042 (setf *delayed-ir1-transforms*
1043 (acons node reasons *delayed-ir1-transforms*))
1044 (throw 'give-up-ir1-transform :delayed))
1046 (dolist (reason reasons)
1047 (pushnew reason (cdr assoc)))
1048 (throw 'give-up-ir1-transform :delayed)))))
1050 ;;; Clear any delayed transform with no reasons - these should have
1051 ;;; been tried in the last pass. Then remove the reason from the
1052 ;;; delayed transform reasons, and if any become empty then set
1053 ;;; reoptimize flags for the node. Return true if any transforms are
1055 (defun retry-delayed-ir1-transforms (reason)
1056 (setf *delayed-ir1-transforms*
1057 (remove-if-not #'cdr *delayed-ir1-transforms*))
1058 (let ((reoptimize nil))
1059 (dolist (assoc *delayed-ir1-transforms*)
1060 (let ((reasons (remove reason (cdr assoc))))
1061 (setf (cdr assoc) reasons)
1063 (let ((node (car assoc)))
1064 (unless (node-deleted node)
1066 (setf (node-reoptimize node) t)
1067 (let ((block (node-block node)))
1068 (setf (block-reoptimize block) t)
1069 (setf (component-reoptimize (block-component block)) t)))))))
1072 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1073 ;;; environment, and then install it as the function for the call
1074 ;;; NODE. We do local call analysis so that the new function is
1075 ;;; integrated into the control flow.
1077 ;;; We require the original function source name in order to generate
1078 ;;; a meaningful debug name for the lambda we set up. (It'd be
1079 ;;; possible to do this starting from debug names as well as source
1080 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1081 ;;; generality, since source names are always known to our callers.)
1082 (defun transform-call (call res source-name)
1083 (declare (type combination call) (list res))
1084 (aver (and (legal-fun-name-p source-name)
1085 (not (eql source-name '.anonymous.))))
1086 (node-ends-block call)
1087 (with-ir1-environment-from-node call
1088 (with-component-last-block (*current-component*
1089 (block-next (node-block call)))
1090 (let ((new-fun (ir1-convert-inline-lambda
1092 :debug-name (debug-namify "LAMBDA-inlined "
1094 "<unknown function>")))
1095 (ref (lvar-use (combination-fun call))))
1096 (change-ref-leaf ref new-fun)
1097 (setf (combination-kind call) :full)
1098 (locall-analyze-component *current-component*))))
1101 ;;; Replace a call to a foldable function of constant arguments with
1102 ;;; the result of evaluating the form. If there is an error during the
1103 ;;; evaluation, we give a warning and leave the call alone, making the
1104 ;;; call a :ERROR call.
1106 ;;; If there is more than one value, then we transform the call into a
1108 (defun constant-fold-call (call)
1109 (let ((args (mapcar #'lvar-value (combination-args call)))
1110 (fun-name (combination-fun-source-name call)))
1111 (multiple-value-bind (values win)
1112 (careful-call fun-name
1115 ;; Note: CMU CL had COMPILER-WARN here, and that
1116 ;; seems more natural, but it's probably not.
1118 ;; It's especially not while bug 173 exists:
1121 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1123 ;; can cause constant-folding TYPE-ERRORs (in
1124 ;; #'<=) when END can be proved to be NIL, even
1125 ;; though the code is perfectly legal and safe
1126 ;; because a NIL value of END means that the
1127 ;; #'<= will never be executed.
1129 ;; Moreover, even without bug 173,
1130 ;; quite-possibly-valid code like
1131 ;; (COND ((NONINLINED-PREDICATE END)
1132 ;; (UNLESS (<= END SIZE))
1134 ;; (where NONINLINED-PREDICATE is something the
1135 ;; compiler can't do at compile time, but which
1136 ;; turns out to make the #'<= expression
1137 ;; unreachable when END=NIL) could cause errors
1138 ;; when the compiler tries to constant-fold (<=
1141 ;; So, with or without bug 173, it'd be
1142 ;; unnecessarily evil to do a full
1143 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1144 ;; from COMPILE-FILE) for legal code, so we we
1145 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1146 #'compiler-style-warn
1149 (setf (combination-kind call) :error))
1150 ((and (proper-list-of-length-p values 1))
1151 (with-ir1-environment-from-node call
1152 (let* ((lvar (node-lvar call))
1153 (prev (node-prev call))
1154 (intermediate-ctran (make-ctran)))
1155 (%delete-lvar-use call)
1156 (setf (ctran-next prev) nil)
1157 (setf (node-prev call) nil)
1158 (reference-constant prev intermediate-ctran lvar
1160 (link-node-to-previous-ctran call intermediate-ctran)
1161 (reoptimize-lvar lvar)
1162 (flush-combination call))))
1163 (t (let ((dummies (make-gensym-list (length args))))
1167 (declare (ignore ,@dummies))
1168 (values ,@(mapcar (lambda (x) `',x) values)))
1172 ;;;; local call optimization
1174 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1175 ;;; the leaf type is a function type, then just leave it alone, since
1176 ;;; TYPE is never going to be more specific than that (and
1177 ;;; TYPE-INTERSECTION would choke.)
1178 (defun propagate-to-refs (leaf type)
1179 (declare (type leaf leaf) (type ctype type))
1180 (let ((var-type (leaf-type leaf)))
1181 (unless (fun-type-p var-type)
1182 (let ((int (type-approx-intersection2 var-type type)))
1183 (when (type/= int var-type)
1184 (setf (leaf-type leaf) int)
1185 (dolist (ref (leaf-refs leaf))
1186 (derive-node-type ref (make-single-value-type int))
1187 ;; KLUDGE: LET var substitution
1188 (let* ((lvar (node-lvar ref)))
1189 (when (and lvar (combination-p (lvar-dest lvar)))
1190 (reoptimize-lvar lvar))))))
1193 ;;; Iteration variable: exactly one SETQ of the form:
1195 ;;; (let ((var initial))
1197 ;;; (setq var (+ var step))
1199 (defun maybe-infer-iteration-var-type (var initial-type)
1200 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1202 (() (null (rest sets)) :exit-if-null)
1203 (set-use (principal-lvar-use (set-value set)))
1204 (() (and (combination-p set-use)
1205 (eq (combination-kind set-use) :known)
1206 (fun-info-p (combination-fun-info set-use))
1207 (not (node-to-be-deleted-p set-use))
1208 (eq (combination-fun-source-name set-use) '+))
1210 (+-args (basic-combination-args set-use))
1211 (() (and (proper-list-of-length-p +-args 2 2)
1212 (let ((first (principal-lvar-use
1215 (eq (ref-leaf first) var))))
1217 (step-type (lvar-type (second +-args)))
1218 (set-type (lvar-type (set-value set))))
1219 (when (and (numeric-type-p initial-type)
1220 (numeric-type-p step-type)
1221 (numeric-type-equal initial-type step-type))
1222 (multiple-value-bind (low high)
1223 (cond ((csubtypep step-type (specifier-type '(real 0 *)))
1224 (values (numeric-type-low initial-type)
1225 (when (and (numeric-type-p set-type)
1226 (numeric-type-equal set-type initial-type))
1227 (numeric-type-high set-type))))
1228 ((csubtypep step-type (specifier-type '(real * 0)))
1229 (values (when (and (numeric-type-p set-type)
1230 (numeric-type-equal set-type initial-type))
1231 (numeric-type-low set-type))
1232 (numeric-type-high initial-type)))
1235 (modified-numeric-type initial-type
1238 :enumerable nil)))))
1239 (deftransform + ((x y) * * :result result)
1240 "check for iteration variable reoptimization"
1241 (let ((dest (principal-lvar-end result))
1242 (use (principal-lvar-use x)))
1243 (when (and (ref-p use)
1247 (reoptimize-lvar (set-value dest))))
1248 (give-up-ir1-transform))
1250 ;;; Figure out the type of a LET variable that has sets. We compute
1251 ;;; the union of the INITIAL-TYPE and the types of all the set
1252 ;;; values and to a PROPAGATE-TO-REFS with this type.
1253 (defun propagate-from-sets (var initial-type)
1254 (collect ((res initial-type type-union))
1255 (dolist (set (basic-var-sets var))
1256 (let ((type (lvar-type (set-value set))))
1258 (when (node-reoptimize set)
1259 (derive-node-type set (make-single-value-type type))
1260 (setf (node-reoptimize set) nil))))
1262 (awhen (maybe-infer-iteration-var-type var initial-type)
1264 (propagate-to-refs var res)))
1267 ;;; If a LET variable, find the initial value's type and do
1268 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1270 (defun ir1-optimize-set (node)
1271 (declare (type cset node))
1272 (let ((var (set-var node)))
1273 (when (and (lambda-var-p var) (leaf-refs var))
1274 (let ((home (lambda-var-home var)))
1275 (when (eq (functional-kind home) :let)
1276 (let* ((initial-value (let-var-initial-value var))
1277 (initial-type (lvar-type initial-value)))
1278 (setf (lvar-reoptimize initial-value) nil)
1279 (propagate-from-sets var initial-type))))))
1281 (derive-node-type node (make-single-value-type
1282 (lvar-type (set-value node))))
1285 ;;; Return true if the value of REF will always be the same (and is
1286 ;;; thus legal to substitute.)
1287 (defun constant-reference-p (ref)
1288 (declare (type ref ref))
1289 (let ((leaf (ref-leaf ref)))
1291 ((or constant functional) t)
1293 (null (lambda-var-sets leaf)))
1295 (not (eq (defined-fun-inlinep leaf) :notinline)))
1297 (case (global-var-kind leaf)
1299 (let ((name (leaf-source-name leaf)))
1301 (eq (symbol-package (fun-name-block-name name))
1303 (info :function :info name)))))))))
1305 ;;; If we have a non-set LET var with a single use, then (if possible)
1306 ;;; replace the variable reference's LVAR with the arg lvar.
1308 ;;; We change the REF to be a reference to NIL with unused value, and
1309 ;;; let it be flushed as dead code. A side effect of this substitution
1310 ;;; is to delete the variable.
1311 (defun substitute-single-use-lvar (arg var)
1312 (declare (type lvar arg) (type lambda-var var))
1313 (binding* ((ref (first (leaf-refs var)))
1314 (lvar (node-lvar ref) :exit-if-null)
1315 (dest (lvar-dest lvar)))
1317 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1318 ;; LVAR-USEs should not be met on one path. Another problem
1319 ;; is with dynamic-extent.
1320 (eq (lvar-uses lvar) ref)
1322 ;; we should not change lifetime of unknown values lvars
1324 (and (type-single-value-p (lvar-derived-type arg))
1325 (multiple-value-bind (pdest pprev)
1326 (principal-lvar-end lvar)
1327 (declare (ignore pdest))
1328 (lvar-single-value-p pprev))))
1330 (or (eq (basic-combination-fun dest) lvar)
1331 (and (eq (basic-combination-kind dest) :local)
1332 (type-single-value-p (lvar-derived-type arg)))))
1334 ;; While CRETURN and EXIT nodes may be known-values,
1335 ;; they have their own complications, such as
1336 ;; substitution into CRETURN may create new tail calls.
1339 (aver (lvar-single-value-p lvar))
1341 (eq (node-home-lambda ref)
1342 (lambda-home (lambda-var-home var))))
1343 (setf (node-derived-type ref) *wild-type*)
1344 (substitute-lvar-uses lvar arg
1345 ;; Really it is (EQ (LVAR-USES LVAR) REF):
1347 (delete-lvar-use ref)
1348 (change-ref-leaf ref (find-constant nil))
1351 (reoptimize-lvar lvar)
1354 ;;; Delete a LET, removing the call and bind nodes, and warning about
1355 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1356 ;;; along right away and delete the REF and then the lambda, since we
1357 ;;; flush the FUN lvar.
1358 (defun delete-let (clambda)
1359 (declare (type clambda clambda))
1360 (aver (functional-letlike-p clambda))
1361 (note-unreferenced-vars clambda)
1362 (let ((call (let-combination clambda)))
1363 (flush-dest (basic-combination-fun call))
1365 (unlink-node (lambda-bind clambda))
1366 (setf (lambda-bind clambda) nil))
1367 (setf (functional-kind clambda) :zombie)
1368 (let ((home (lambda-home clambda)))
1369 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1372 ;;; This function is called when one of the arguments to a LET
1373 ;;; changes. We look at each changed argument. If the corresponding
1374 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1375 ;;; consider substituting for the variable, and also propagate
1376 ;;; derived-type information for the arg to all the VAR's refs.
1378 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1379 ;;; subtype of the argument's leaf type. This prevents type checking
1380 ;;; from being defeated, and also ensures that the best representation
1381 ;;; for the variable can be used.
1383 ;;; Substitution of individual references is inhibited if the
1384 ;;; reference is in a different component from the home. This can only
1385 ;;; happen with closures over top level lambda vars. In such cases,
1386 ;;; the references may have already been compiled, and thus can't be
1387 ;;; retroactively modified.
1389 ;;; If all of the variables are deleted (have no references) when we
1390 ;;; are done, then we delete the LET.
1392 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1394 (defun propagate-let-args (call fun)
1395 (declare (type combination call) (type clambda fun))
1396 (loop for arg in (combination-args call)
1397 and var in (lambda-vars fun) do
1398 (when (and arg (lvar-reoptimize arg))
1399 (setf (lvar-reoptimize arg) nil)
1401 ((lambda-var-sets var)
1402 (propagate-from-sets var (lvar-type arg)))
1403 ((let ((use (lvar-uses arg)))
1405 (let ((leaf (ref-leaf use)))
1406 (when (and (constant-reference-p use)
1407 (csubtypep (leaf-type leaf)
1408 ;; (NODE-DERIVED-TYPE USE) would
1409 ;; be better -- APD, 2003-05-15
1411 (propagate-to-refs var (lvar-type arg))
1412 (let ((use-component (node-component use)))
1413 (prog1 (substitute-leaf-if
1415 (cond ((eq (node-component ref) use-component)
1418 (aver (lambda-toplevelish-p (lambda-home fun)))
1422 ((and (null (rest (leaf-refs var)))
1423 (substitute-single-use-lvar arg var)))
1425 (propagate-to-refs var (lvar-type arg))))))
1427 (when (every #'not (combination-args call))
1432 ;;; This function is called when one of the args to a non-LET local
1433 ;;; call changes. For each changed argument corresponding to an unset
1434 ;;; variable, we compute the union of the types across all calls and
1435 ;;; propagate this type information to the var's refs.
1437 ;;; If the function has an XEP, then we don't do anything, since we
1438 ;;; won't discover anything.
1440 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1441 ;;; corresponding to changed arguments in CALL, since the only use in
1442 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1444 (defun propagate-local-call-args (call fun)
1445 (declare (type combination call) (type clambda fun))
1447 (unless (or (functional-entry-fun fun)
1448 (lambda-optional-dispatch fun))
1449 (let* ((vars (lambda-vars fun))
1450 (union (mapcar (lambda (arg var)
1452 (lvar-reoptimize arg)
1453 (null (basic-var-sets var)))
1455 (basic-combination-args call)
1457 (this-ref (lvar-use (basic-combination-fun call))))
1459 (dolist (arg (basic-combination-args call))
1461 (setf (lvar-reoptimize arg) nil)))
1463 (dolist (ref (leaf-refs fun))
1464 (let ((dest (node-dest ref)))
1465 (unless (or (eq ref this-ref) (not dest))
1467 (mapcar (lambda (this-arg old)
1469 (setf (lvar-reoptimize this-arg) nil)
1470 (type-union (lvar-type this-arg) old)))
1471 (basic-combination-args dest)
1474 (loop for var in vars
1476 when type do (propagate-to-refs var type))))
1480 ;;;; multiple values optimization
1482 ;;; Do stuff to notice a change to a MV combination node. There are
1483 ;;; two main branches here:
1484 ;;; -- If the call is local, then it is already a MV let, or should
1485 ;;; become one. Note that although all :LOCAL MV calls must eventually
1486 ;;; be converted to :MV-LETs, there can be a window when the call
1487 ;;; is local, but has not been LET converted yet. This is because
1488 ;;; the entry-point lambdas may have stray references (in other
1489 ;;; entry points) that have not been deleted yet.
1490 ;;; -- The call is full. This case is somewhat similar to the non-MV
1491 ;;; combination optimization: we propagate return type information and
1492 ;;; notice non-returning calls. We also have an optimization
1493 ;;; which tries to convert MV-CALLs into MV-binds.
1494 (defun ir1-optimize-mv-combination (node)
1495 (ecase (basic-combination-kind node)
1497 (let ((fun-lvar (basic-combination-fun node)))
1498 (when (lvar-reoptimize fun-lvar)
1499 (setf (lvar-reoptimize fun-lvar) nil)
1500 (maybe-let-convert (combination-lambda node))))
1501 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1502 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1503 (unless (convert-mv-bind-to-let node)
1504 (ir1-optimize-mv-bind node))))
1506 (let* ((fun (basic-combination-fun node))
1507 (fun-changed (lvar-reoptimize fun))
1508 (args (basic-combination-args node)))
1510 (setf (lvar-reoptimize fun) nil)
1511 (let ((type (lvar-type fun)))
1512 (when (fun-type-p type)
1513 (derive-node-type node (fun-type-returns type))))
1514 (maybe-terminate-block node nil)
1515 (let ((use (lvar-uses fun)))
1516 (when (and (ref-p use) (functional-p (ref-leaf use)))
1517 (convert-call-if-possible use node)
1518 (when (eq (basic-combination-kind node) :local)
1519 (maybe-let-convert (ref-leaf use))))))
1520 (unless (or (eq (basic-combination-kind node) :local)
1521 (eq (lvar-fun-name fun) '%throw))
1522 (ir1-optimize-mv-call node))
1524 (setf (lvar-reoptimize arg) nil))))
1528 ;;; Propagate derived type info from the values lvar to the vars.
1529 (defun ir1-optimize-mv-bind (node)
1530 (declare (type mv-combination node))
1531 (let* ((arg (first (basic-combination-args node)))
1532 (vars (lambda-vars (combination-lambda node)))
1533 (n-vars (length vars))
1534 (types (values-type-in (lvar-derived-type arg)
1536 (loop for var in vars
1538 do (if (basic-var-sets var)
1539 (propagate-from-sets var type)
1540 (propagate-to-refs var type)))
1541 (setf (lvar-reoptimize arg) nil))
1544 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1546 ;;; -- The call has only one argument, and
1547 ;;; -- The function has a known fixed number of arguments, or
1548 ;;; -- The argument yields a known fixed number of values.
1550 ;;; What we do is change the function in the MV-CALL to be a lambda
1551 ;;; that "looks like an MV bind", which allows
1552 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1553 ;;; converted (the next time around.) This new lambda just calls the
1554 ;;; actual function with the MV-BIND variables as arguments. Note that
1555 ;;; this new MV bind is not let-converted immediately, as there are
1556 ;;; going to be stray references from the entry-point functions until
1557 ;;; they get deleted.
1559 ;;; In order to avoid loss of argument count checking, we only do the
1560 ;;; transformation according to a known number of expected argument if
1561 ;;; safety is unimportant. We can always convert if we know the number
1562 ;;; of actual values, since the normal call that we build will still
1563 ;;; do any appropriate argument count checking.
1565 ;;; We only attempt the transformation if the called function is a
1566 ;;; constant reference. This allows us to just splice the leaf into
1567 ;;; the new function, instead of trying to somehow bind the function
1568 ;;; expression. The leaf must be constant because we are evaluating it
1569 ;;; again in a different place. This also has the effect of squelching
1570 ;;; multiple warnings when there is an argument count error.
1571 (defun ir1-optimize-mv-call (node)
1572 (let ((fun (basic-combination-fun node))
1573 (*compiler-error-context* node)
1574 (ref (lvar-uses (basic-combination-fun node)))
1575 (args (basic-combination-args node)))
1577 (unless (and (ref-p ref) (constant-reference-p ref)
1579 (return-from ir1-optimize-mv-call))
1581 (multiple-value-bind (min max)
1582 (fun-type-nargs (lvar-type fun))
1584 (multiple-value-bind (types nvals)
1585 (values-types (lvar-derived-type (first args)))
1586 (declare (ignore types))
1587 (if (eq nvals :unknown) nil nvals))))
1590 (when (and min (< total-nvals min))
1592 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1595 (setf (basic-combination-kind node) :error)
1596 (return-from ir1-optimize-mv-call))
1597 (when (and max (> total-nvals max))
1599 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1602 (setf (basic-combination-kind node) :error)
1603 (return-from ir1-optimize-mv-call)))
1605 (let ((count (cond (total-nvals)
1606 ((and (policy node (zerop verify-arg-count))
1611 (with-ir1-environment-from-node node
1612 (let* ((dums (make-gensym-list count))
1614 (fun (ir1-convert-lambda
1615 `(lambda (&optional ,@dums &rest ,ignore)
1616 (declare (ignore ,ignore))
1617 (funcall ,(ref-leaf ref) ,@dums)))))
1618 (change-ref-leaf ref fun)
1619 (aver (eq (basic-combination-kind node) :full))
1620 (locall-analyze-component *current-component*)
1621 (aver (eq (basic-combination-kind node) :local)))))))))
1625 ;;; (multiple-value-bind
1634 ;;; What we actually do is convert the VALUES combination into a
1635 ;;; normal LET combination calling the original :MV-LET lambda. If
1636 ;;; there are extra args to VALUES, discard the corresponding
1637 ;;; lvars. If there are insufficient args, insert references to NIL.
1638 (defun convert-mv-bind-to-let (call)
1639 (declare (type mv-combination call))
1640 (let* ((arg (first (basic-combination-args call)))
1641 (use (lvar-uses arg)))
1642 (when (and (combination-p use)
1643 (eq (lvar-fun-name (combination-fun use))
1645 (let* ((fun (combination-lambda call))
1646 (vars (lambda-vars fun))
1647 (vals (combination-args use))
1648 (nvars (length vars))
1649 (nvals (length vals)))
1650 (cond ((> nvals nvars)
1651 (mapc #'flush-dest (subseq vals nvars))
1652 (setq vals (subseq vals 0 nvars)))
1654 (with-ir1-environment-from-node use
1655 (let ((node-prev (node-prev use)))
1656 (setf (node-prev use) nil)
1657 (setf (ctran-next node-prev) nil)
1658 (collect ((res vals))
1659 (loop for count below (- nvars nvals)
1660 for prev = node-prev then ctran
1661 for ctran = (make-ctran)
1662 and lvar = (make-lvar use)
1663 do (reference-constant prev ctran lvar nil)
1665 finally (link-node-to-previous-ctran
1667 (setq vals (res)))))))
1668 (setf (combination-args use) vals)
1669 (flush-dest (combination-fun use))
1670 (let ((fun-lvar (basic-combination-fun call)))
1671 (setf (lvar-dest fun-lvar) use)
1672 (setf (combination-fun use) fun-lvar)
1673 (flush-lvar-externally-checkable-type fun-lvar))
1674 (setf (combination-kind use) :local)
1675 (setf (functional-kind fun) :let)
1676 (flush-dest (first (basic-combination-args call)))
1679 (reoptimize-lvar (first vals)))
1680 (propagate-to-args use fun)
1681 (reoptimize-call use))
1685 ;;; (values-list (list x y z))
1690 ;;; In implementation, this is somewhat similar to
1691 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1692 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1693 ;;; (allowing the LIST to be flushed.)
1695 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1696 (defoptimizer (values-list optimizer) ((list) node)
1697 (let ((use (lvar-uses list)))
1698 (when (and (combination-p use)
1699 (eq (lvar-fun-name (combination-fun use))
1702 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1703 (change-ref-leaf (lvar-uses (combination-fun node))
1704 (find-free-fun 'values "in a strange place"))
1705 (setf (combination-kind node) :full)
1706 (let ((args (combination-args use)))
1708 (setf (lvar-dest arg) node)
1709 (flush-lvar-externally-checkable-type arg))
1710 (setf (combination-args use) nil)
1712 (setf (combination-args node) args))
1715 ;;; If VALUES appears in a non-MV context, then effectively convert it
1716 ;;; to a PROG1. This allows the computation of the additional values
1717 ;;; to become dead code.
1718 (deftransform values ((&rest vals) * * :node node)
1719 (unless (lvar-single-value-p (node-lvar node))
1720 (give-up-ir1-transform))
1721 (setf (node-derived-type node)
1722 (make-short-values-type (list (single-value-type
1723 (node-derived-type node)))))
1724 (principal-lvar-single-valuify (node-lvar node))
1726 (let ((dummies (make-gensym-list (length (cdr vals)))))
1727 `(lambda (val ,@dummies)
1728 (declare (ignore ,@dummies))
1734 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1735 (declare (type cast cast))
1736 (let ((value (cast-value cast))
1737 (atype (cast-asserted-type cast)))
1738 (when (not do-not-optimize)
1739 (let ((lvar (node-lvar cast)))
1740 (when (values-subtypep (lvar-derived-type value)
1741 (cast-asserted-type cast))
1742 (delete-filter cast lvar value)
1744 (reoptimize-lvar lvar)
1745 (when (lvar-single-value-p lvar)
1746 (note-single-valuified-lvar lvar)))
1747 (return-from ir1-optimize-cast t))
1749 (when (and (listp (lvar-uses value))
1751 ;; Pathwise removing of CAST
1752 (let ((ctran (node-next cast))
1753 (dest (lvar-dest lvar))
1756 (do-uses (use value)
1757 (when (and (values-subtypep (node-derived-type use) atype)
1758 (immediately-used-p value use))
1760 (when ctran (ensure-block-start ctran))
1761 (setq next-block (first (block-succ (node-block cast))))
1762 (ensure-block-start (node-prev cast))
1763 (reoptimize-lvar lvar)
1764 (setf (lvar-%derived-type value) nil))
1765 (%delete-lvar-use use)
1766 (add-lvar-use use lvar)
1767 (unlink-blocks (node-block use) (node-block cast))
1768 (link-blocks (node-block use) next-block)
1769 (when (and (return-p dest)
1770 (basic-combination-p use)
1771 (eq (basic-combination-kind use) :local))
1773 (dolist (use (merges))
1774 (merge-tail-sets use)))))))
1776 (let* ((value-type (lvar-derived-type value))
1777 (int (values-type-intersection value-type atype)))
1778 (derive-node-type cast int)
1779 (when (eq int *empty-type*)
1780 (unless (eq value-type *empty-type*)
1782 ;; FIXME: Do it in one step.
1785 (if (cast-single-value-p cast)
1787 `(multiple-value-call #'list 'dummy)))
1790 ;; FIXME: Derived type.
1791 `(%compile-time-type-error 'dummy
1792 ',(type-specifier atype)
1793 ',(type-specifier value-type)))
1794 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1795 ;; functions, so we declare the return type of
1796 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1798 (setq value (cast-value cast))
1799 (derive-node-type (lvar-uses value) *empty-type*)
1800 (maybe-terminate-block (lvar-uses value) nil)
1801 ;; FIXME: Is it necessary?
1802 (aver (null (block-pred (node-block cast))))
1803 (delete-block-lazily (node-block cast))
1804 (return-from ir1-optimize-cast)))
1805 (when (eq (node-derived-type cast) *empty-type*)
1806 (maybe-terminate-block cast nil))
1808 (when (and (cast-%type-check cast)
1809 (values-subtypep value-type
1810 (cast-type-to-check cast)))
1811 (setf (cast-%type-check cast) nil))))
1813 (unless do-not-optimize
1814 (setf (node-reoptimize cast) nil)))