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)))
343 (join-blocks block next)
346 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
347 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
348 ;;; for the two blocks so that any indicated optimization gets done.
349 (defun join-blocks (block1 block2)
350 (declare (type cblock block1 block2))
351 (let* ((last1 (block-last block1))
352 (last2 (block-last block2))
353 (succ (block-succ block2))
354 (start2 (block-start block2)))
355 (do ((ctran start2 (node-next (ctran-next ctran))))
357 (setf (ctran-block ctran) block1))
359 (unlink-blocks block1 block2)
361 (unlink-blocks block2 block)
362 (link-blocks block1 block))
364 (setf (ctran-kind start2) :inside-block)
365 (setf (node-next last1) start2)
366 (setf (ctran-use start2) last1)
367 (setf (block-last block1) last2))
369 (setf (block-flags block1)
370 (attributes-union (block-flags block1)
372 (block-attributes type-asserted test-modified)))
374 (let ((next (block-next block2))
375 (prev (block-prev block2)))
376 (setf (block-next prev) next)
377 (setf (block-prev next) prev))
381 ;;; Delete any nodes in BLOCK whose value is unused and which have no
382 ;;; side effects. We can delete sets of lexical variables when the set
383 ;;; variable has no references.
384 (defun flush-dead-code (block)
385 (declare (type cblock block))
386 (setf (block-flush-p block) nil)
387 (do-nodes-backwards (node lvar block :restart-p t)
394 (let ((kind (combination-kind node))
395 (info (combination-fun-info node)))
396 (when (and (eq kind :known) (fun-info-p info))
397 (let ((attr (fun-info-attributes info)))
398 (when (and (not (ir1-attributep attr call))
399 ;; ### For now, don't delete potentially
400 ;; flushable calls when they have the CALL
401 ;; attribute. Someday we should look at the
402 ;; functional args to determine if they have
404 (if (policy node (= safety 3))
405 (ir1-attributep attr flushable)
406 (ir1-attributep attr unsafely-flushable)))
407 (flush-combination node))))))
409 (when (eq (basic-combination-kind node) :local)
410 (let ((fun (combination-lambda node)))
411 (when (dolist (var (lambda-vars fun) t)
412 (when (or (leaf-refs var)
413 (lambda-var-sets var))
415 (flush-dest (first (basic-combination-args node)))
418 (let ((value (exit-value node)))
421 (setf (exit-value node) nil))))
423 (let ((var (set-var node)))
424 (when (and (lambda-var-p var)
425 (null (leaf-refs var)))
426 (flush-dest (set-value node))
427 (setf (basic-var-sets var)
428 (delq node (basic-var-sets var)))
429 (unlink-node node))))
431 (unless (cast-type-check node)
432 (flush-dest (cast-value node))
433 (unlink-node node))))))
437 ;;;; local call return type propagation
439 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
440 ;;; flag set. It iterates over the uses of the RESULT, looking for
441 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
442 ;;; call, then we union its type together with the types of other such
443 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
444 ;;; type with the RESULT's asserted type. We can make this
445 ;;; intersection now (potentially before type checking) because this
446 ;;; assertion on the result will eventually be checked (if
449 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
450 ;;; combination, which may change the succesor of the call to be the
451 ;;; called function, and if so, checks if the call can become an
452 ;;; assignment. If we convert to an assignment, we abort, since the
453 ;;; RETURN has been deleted.
454 (defun find-result-type (node)
455 (declare (type creturn node))
456 (let ((result (return-result node)))
457 (collect ((use-union *empty-type* values-type-union))
458 (do-uses (use result)
459 (let ((use-home (node-home-lambda use)))
460 (cond ((or (eq (functional-kind use-home) :deleted)
461 (block-delete-p (node-block use))))
462 ((and (basic-combination-p use)
463 (eq (basic-combination-kind use) :local))
464 (aver (eq (lambda-tail-set use-home)
465 (lambda-tail-set (combination-lambda use))))
466 (when (combination-p use)
467 (when (nth-value 1 (maybe-convert-tail-local-call use))
468 (return-from find-result-type t))))
470 (use-union (node-derived-type use))))))
472 ;; (values-type-intersection
473 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
477 (setf (return-result-type node) int))))
480 ;;; Do stuff to realize that something has changed about the value
481 ;;; delivered to a return node. Since we consider the return values of
482 ;;; all functions in the tail set to be equivalent, this amounts to
483 ;;; bringing the entire tail set up to date. We iterate over the
484 ;;; returns for all the functions in the tail set, reanalyzing them
485 ;;; all (not treating NODE specially.)
487 ;;; When we are done, we check whether the new type is different from
488 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
489 ;;; all the lvars for references to functions in the tail set. This
490 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
491 ;;; results of the calls.
492 (defun ir1-optimize-return (node)
493 (declare (type creturn node))
496 (let* ((tails (lambda-tail-set (return-lambda node)))
497 (funs (tail-set-funs tails)))
498 (collect ((res *empty-type* values-type-union))
500 (let ((return (lambda-return fun)))
502 (when (node-reoptimize return)
503 (setf (node-reoptimize return) nil)
504 (when (find-result-type return)
506 (res (return-result-type return)))))
508 (when (type/= (res) (tail-set-type tails))
509 (setf (tail-set-type tails) (res))
510 (dolist (fun (tail-set-funs tails))
511 (dolist (ref (leaf-refs fun))
512 (reoptimize-lvar (node-lvar ref))))))))
518 ;;; If the test has multiple uses, replicate the node when possible.
519 ;;; Also check whether the predicate is known to be true or false,
520 ;;; deleting the IF node in favor of the appropriate branch when this
522 (defun ir1-optimize-if (node)
523 (declare (type cif node))
524 (let ((test (if-test node))
525 (block (node-block node)))
527 (when (and (eq (block-start-node block) node)
528 (listp (lvar-uses test)))
530 (when (immediately-used-p test use)
531 (convert-if-if use node)
532 (when (not (listp (lvar-uses test))) (return)))))
534 (let* ((type (lvar-type test))
536 (cond ((constant-lvar-p test)
537 (if (lvar-value test)
538 (if-alternative node)
539 (if-consequent node)))
540 ((not (types-equal-or-intersect type (specifier-type 'null)))
541 (if-alternative node))
542 ((type= type (specifier-type 'null))
543 (if-consequent node)))))
546 (when (rest (block-succ block))
547 (unlink-blocks block victim))
548 (setf (component-reanalyze (node-component node)) t)
549 (unlink-node node))))
552 ;;; Create a new copy of an IF node that tests the value of the node
553 ;;; USE. The test must have >1 use, and must be immediately used by
554 ;;; USE. NODE must be the only node in its block (implying that
555 ;;; block-start = if-test).
557 ;;; This optimization has an effect semantically similar to the
558 ;;; source-to-source transformation:
559 ;;; (IF (IF A B C) D E) ==>
560 ;;; (IF A (IF B D E) (IF C D E))
562 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
563 ;;; node so that dead code deletion notes will definitely not consider
564 ;;; either node to be part of the original source. One node might
565 ;;; become unreachable, resulting in a spurious note.
566 (defun convert-if-if (use node)
567 (declare (type node use) (type cif node))
568 (with-ir1-environment-from-node node
569 (let* ((block (node-block node))
570 (test (if-test node))
571 (cblock (if-consequent node))
572 (ablock (if-alternative node))
573 (use-block (node-block use))
574 (new-ctran (make-ctran))
575 (new-lvar (make-lvar))
576 (new-node (make-if :test new-lvar
578 :alternative ablock))
579 (new-block (ctran-starts-block new-ctran)))
580 (link-node-to-previous-ctran new-node new-ctran)
581 (setf (lvar-dest new-lvar) new-node)
582 (setf (block-last new-block) new-node)
584 (unlink-blocks use-block block)
585 (%delete-lvar-use use)
586 (add-lvar-use use new-lvar)
587 (link-blocks use-block new-block)
589 (link-blocks new-block cblock)
590 (link-blocks new-block ablock)
592 (push "<IF Duplication>" (node-source-path node))
593 (push "<IF Duplication>" (node-source-path new-node))
595 (reoptimize-lvar test)
596 (reoptimize-lvar new-lvar)
597 (setf (component-reanalyze *current-component*) t)))
600 ;;;; exit IR1 optimization
602 ;;; This function attempts to delete an exit node, returning true if
603 ;;; it deletes the block as a consequence:
604 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
605 ;;; anything, since there is nothing to be done.
606 ;;; -- If the exit node and its ENTRY have the same home lambda then
607 ;;; we know the exit is local, and can delete the exit. We change
608 ;;; uses of the Exit-Value to be uses of the original lvar,
609 ;;; then unlink the node. If the exit is to a TR context, then we
610 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
611 ;;; their value to this exit.
612 ;;; -- If there is no value (as in a GO), then we skip the value
615 ;;; This function is also called by environment analysis, since it
616 ;;; wants all exits to be optimized even if normal optimization was
618 (defun maybe-delete-exit (node)
619 (declare (type exit node))
620 (let ((value (exit-value node))
621 (entry (exit-entry node)))
623 (eq (node-home-lambda node) (node-home-lambda entry)))
624 (setf (entry-exits entry) (delq node (entry-exits entry)))
626 (delete-filter node (node-lvar node) value)
627 (unlink-node node)))))
630 ;;;; combination IR1 optimization
632 ;;; Report as we try each transform?
634 (defvar *show-transforms-p* nil)
636 ;;; Do IR1 optimizations on a COMBINATION node.
637 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
638 (defun ir1-optimize-combination (node)
639 (when (lvar-reoptimize (basic-combination-fun node))
640 (propagate-fun-change node)
641 (maybe-terminate-block node nil))
642 (let ((args (basic-combination-args node))
643 (kind (basic-combination-kind node))
644 (info (basic-combination-fun-info node)))
647 (let ((fun (combination-lambda node)))
648 (if (eq (functional-kind fun) :let)
649 (propagate-let-args node fun)
650 (propagate-local-call-args node fun))))
654 (setf (lvar-reoptimize arg) nil))))
658 (setf (lvar-reoptimize arg) nil)))
660 (let ((fun (fun-info-derive-type info)))
662 (let ((res (funcall fun node)))
664 (derive-node-type node (coerce-to-values res))
665 (maybe-terminate-block node nil)))))))
670 (setf (lvar-reoptimize arg) nil)))
672 (let ((attr (fun-info-attributes info)))
673 (when (and (ir1-attributep attr foldable)
674 ;; KLUDGE: The next test could be made more sensitive,
675 ;; only suppressing constant-folding of functions with
676 ;; CALL attributes when they're actually passed
677 ;; function arguments. -- WHN 19990918
678 (not (ir1-attributep attr call))
679 (every #'constant-lvar-p args)
681 ;; Even if the function is foldable in principle,
682 ;; it might be one of our low-level
683 ;; implementation-specific functions. Such
684 ;; functions don't necessarily exist at runtime on
685 ;; a plain vanilla ANSI Common Lisp
686 ;; cross-compilation host, in which case the
687 ;; cross-compiler can't fold it because the
688 ;; cross-compiler doesn't know how to evaluate it.
690 (or (fboundp (combination-fun-source-name node))
691 (progn (format t ";;; !!! Unbound fun: (~S~{ ~S~})~%"
692 (combination-fun-source-name node)
693 (mapcar #'lvar-value args))
695 (constant-fold-call node)
696 (return-from ir1-optimize-combination)))
698 (let ((fun (fun-info-derive-type info)))
700 (let ((res (funcall fun node)))
702 (derive-node-type node (coerce-to-values res))
703 (maybe-terminate-block node nil)))))
705 (let ((fun (fun-info-optimizer info)))
706 (unless (and fun (funcall fun node))
707 (dolist (x (fun-info-transforms info))
709 (when *show-transforms-p*
710 (let* ((lvar (basic-combination-fun node))
711 (fname (lvar-fun-name lvar t)))
712 (/show "trying transform" x (transform-function x) "for" fname)))
713 (unless (ir1-transform node x)
715 (when *show-transforms-p*
716 (/show "quitting because IR1-TRANSFORM result was NIL"))
721 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
722 ;;; the block there, and link it to the component tail.
724 ;;; Except when called during IR1 convertion, we delete the
725 ;;; continuation if it has no other uses. (If it does have other uses,
728 ;;; Termination on the basis of a continuation type is
730 ;;; -- The continuation is deleted (hence the assertion is spurious), or
731 ;;; -- We are in IR1 conversion (where THE assertions are subject to
732 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
733 ;;; uses can(?) be added later. -- APD, 2003-07-17
735 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
736 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
737 (declare (type (or basic-combination cast) node))
738 (let* ((block (node-block node))
739 (lvar (node-lvar node))
740 (ctran (node-next node))
741 (tail (component-tail (block-component block)))
742 (succ (first (block-succ block))))
743 (unless (or (and (eq node (block-last block)) (eq succ tail))
744 (block-delete-p block))
745 (when (eq (node-derived-type node) *empty-type*)
746 (cond (ir1-converting-not-optimizing-p
749 (aver (eq (block-last block) node)))
751 (setf (block-last block) node)
752 (setf (ctran-use ctran) nil)
753 (setf (ctran-kind ctran) :unused)
754 (setf (ctran-block ctran) nil)
755 (setf (node-next node) nil)
756 (link-blocks block (ctran-starts-block ctran)))))
758 (node-ends-block node)))
760 (unlink-blocks block (first (block-succ block)))
761 (setf (component-reanalyze (block-component block)) t)
762 (aver (not (block-succ block)))
763 (link-blocks block tail)
764 (if ir1-converting-not-optimizing-p
765 (%delete-lvar-use node)
766 (delete-lvar-use node))
769 ;;; This is called both by IR1 conversion and IR1 optimization when
770 ;;; they have verified the type signature for the call, and are
771 ;;; wondering if something should be done to special-case the call. If
772 ;;; CALL is a call to a global function, then see whether it defined
774 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
775 ;;; the expansion and change the call to call it. Expansion is
776 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
777 ;;; true, we never expand, since this function has already been
778 ;;; converted. Local call analysis will duplicate the definition
779 ;;; if necessary. We claim that the parent form is LABELS for
780 ;;; context declarations, since we don't want it to be considered
781 ;;; a real global function.
782 ;;; -- If it is a known function, mark it as such by setting the KIND.
784 ;;; We return the leaf referenced (NIL if not a leaf) and the
785 ;;; FUN-INFO assigned.
786 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
787 (declare (type combination call))
788 (let* ((ref (lvar-uses (basic-combination-fun call)))
789 (leaf (when (ref-p ref) (ref-leaf ref)))
790 (inlinep (if (defined-fun-p leaf)
791 (defined-fun-inlinep leaf)
794 ((eq inlinep :notinline)
795 (let ((info (info :function :info (leaf-source-name leaf))))
797 (setf (basic-combination-fun-info call) info))
799 ((not (and (global-var-p leaf)
800 (eq (global-var-kind leaf) :global-function)))
805 ((nil :maybe-inline) (policy call (zerop space))))
807 (defined-fun-inline-expansion leaf)
808 (let ((fun (defined-fun-functional leaf)))
810 (and (eq inlinep :inline) (functional-kind fun))))
811 (inline-expansion-ok call))
812 (flet (;; FIXME: Is this what the old CMU CL internal documentation
813 ;; called semi-inlining? A more descriptive name would
814 ;; be nice. -- WHN 2002-01-07
816 (let ((res (ir1-convert-lambda-for-defun
817 (defined-fun-inline-expansion leaf)
819 #'ir1-convert-inline-lambda)))
820 (setf (defined-fun-functional leaf) res)
821 (change-ref-leaf ref res))))
822 (if ir1-converting-not-optimizing-p
824 (with-ir1-environment-from-node call
826 (locall-analyze-component *current-component*))))
828 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
831 (let ((info (info :function :info (leaf-source-name leaf))))
835 (setf (basic-combination-kind call) :known)
836 (setf (basic-combination-fun-info call) info)))
837 (values leaf nil)))))))
839 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
840 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
841 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
842 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
843 ;;; syntax check, arg/result type processing, but still call
844 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
845 ;;; and that checking is done by local call analysis.
846 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
847 (declare (type combination call) (type ctype type))
848 (cond ((not (fun-type-p type))
849 (aver (multiple-value-bind (val win)
850 (csubtypep type (specifier-type 'function))
852 (recognize-known-call call ir1-converting-not-optimizing-p))
853 ((valid-fun-use call type
854 :argument-test #'always-subtypep
856 ;; KLUDGE: Common Lisp is such a dynamic
857 ;; language that all we can do here in
858 ;; general is issue a STYLE-WARNING. It
859 ;; would be nice to issue a full WARNING
860 ;; in the special case of of type
861 ;; mismatches within a compilation unit
862 ;; (as in section 3.2.2.3 of the spec)
863 ;; but at least as of sbcl-0.6.11, we
864 ;; don't keep track of whether the
865 ;; mismatched data came from the same
866 ;; compilation unit, so we can't do that.
869 ;; FIXME: Actually, I think we could
870 ;; issue a full WARNING if the call
871 ;; violates a DECLAIM FTYPE.
872 :lossage-fun #'compiler-style-warn
873 :unwinnage-fun #'compiler-notify)
874 (assert-call-type call type)
875 (maybe-terminate-block call ir1-converting-not-optimizing-p)
876 (recognize-known-call call ir1-converting-not-optimizing-p))
878 (setf (combination-kind call) :error)
881 ;;; This is called by IR1-OPTIMIZE when the function for a call has
882 ;;; changed. If the call is local, we try to LET-convert it, and
883 ;;; derive the result type. If it is a :FULL call, we validate it
884 ;;; against the type, which recognizes known calls, does inline
885 ;;; expansion, etc. If a call to a predicate in a non-conditional
886 ;;; position or to a function with a source transform, then we
887 ;;; reconvert the form to give IR1 another chance.
888 (defun propagate-fun-change (call)
889 (declare (type combination call))
890 (let ((*compiler-error-context* call)
891 (fun-lvar (basic-combination-fun call)))
892 (setf (lvar-reoptimize fun-lvar) nil)
893 (case (combination-kind call)
895 (let ((fun (combination-lambda call)))
896 (maybe-let-convert fun)
897 (unless (member (functional-kind fun) '(:let :assignment :deleted))
898 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
900 (multiple-value-bind (leaf info)
901 (validate-call-type call (lvar-type fun-lvar) nil)
902 (cond ((functional-p leaf)
903 (convert-call-if-possible
904 (lvar-uses (basic-combination-fun call))
907 ((and (leaf-has-source-name-p leaf)
908 (or (info :function :source-transform (leaf-source-name leaf))
910 (ir1-attributep (fun-info-attributes info)
912 (let ((lvar (node-lvar call)))
913 (and lvar (not (if-p (lvar-dest lvar))))))))
914 (let ((name (leaf-source-name leaf))
915 (dummies (make-gensym-list
916 (length (combination-args call)))))
919 (,@(if (symbolp name)
923 (leaf-source-name leaf)))))))))
926 ;;;; known function optimization
928 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
929 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
930 ;;; replace it, otherwise add a new one.
931 (defun record-optimization-failure (node transform args)
932 (declare (type combination node) (type transform transform)
933 (type (or fun-type list) args))
934 (let* ((table (component-failed-optimizations *component-being-compiled*))
935 (found (assoc transform (gethash node table))))
937 (setf (cdr found) args)
938 (push (cons transform args) (gethash node table))))
941 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
942 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
943 ;;; doing the transform for some reason and FLAME is true, then we
944 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
945 ;;; finalize to pick up. We return true if the transform failed, and
946 ;;; thus further transformation should be attempted. We return false
947 ;;; if either the transform succeeded or was aborted.
948 (defun ir1-transform (node transform)
949 (declare (type combination node) (type transform transform))
950 (let* ((type (transform-type transform))
951 (fun (transform-function transform))
952 (constrained (fun-type-p type))
953 (table (component-failed-optimizations *component-being-compiled*))
954 (flame (if (transform-important transform)
955 (policy node (>= speed inhibit-warnings))
956 (policy node (> speed inhibit-warnings))))
957 (*compiler-error-context* node))
958 (cond ((or (not constrained)
959 (valid-fun-use node type))
960 (multiple-value-bind (severity args)
961 (catch 'give-up-ir1-transform
964 (combination-fun-source-name node))
971 (setf (combination-kind node) :error)
973 (apply #'compiler-warn args))
979 (record-optimization-failure node transform args))
980 (setf (gethash node table)
981 (remove transform (gethash node table) :key #'car)))
989 :argument-test #'types-equal-or-intersect
990 :result-test #'values-types-equal-or-intersect))
991 (record-optimization-failure node transform type)
996 ;;; When we don't like an IR1 transform, we throw the severity/reason
999 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1000 ;;; aborting this attempt to transform the call, but admitting the
1001 ;;; possibility that this or some other transform will later succeed.
1002 ;;; If arguments are supplied, they are format arguments for an
1003 ;;; efficiency note.
1005 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1006 ;;; force a normal call to the function at run time. No further
1007 ;;; optimizations will be attempted.
1009 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1010 ;;; delay the transform on the node until later. REASONS specifies
1011 ;;; when the transform will be later retried. The :OPTIMIZE reason
1012 ;;; causes the transform to be delayed until after the current IR1
1013 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1014 ;;; be delayed until after constraint propagation.
1016 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1017 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1018 ;;; do CASE operations on the various REASON values, it might be a
1019 ;;; good idea to go OO, representing the reasons by objects, using
1020 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1021 ;;; SIGNAL instead of THROW.
1022 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1023 (defun give-up-ir1-transform (&rest args)
1024 (throw 'give-up-ir1-transform (values :failure args)))
1025 (defun abort-ir1-transform (&rest args)
1026 (throw 'give-up-ir1-transform (values :aborted args)))
1027 (defun delay-ir1-transform (node &rest reasons)
1028 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1030 (setf *delayed-ir1-transforms*
1031 (acons node reasons *delayed-ir1-transforms*))
1032 (throw 'give-up-ir1-transform :delayed))
1034 (dolist (reason reasons)
1035 (pushnew reason (cdr assoc)))
1036 (throw 'give-up-ir1-transform :delayed)))))
1038 ;;; Clear any delayed transform with no reasons - these should have
1039 ;;; been tried in the last pass. Then remove the reason from the
1040 ;;; delayed transform reasons, and if any become empty then set
1041 ;;; reoptimize flags for the node. Return true if any transforms are
1043 (defun retry-delayed-ir1-transforms (reason)
1044 (setf *delayed-ir1-transforms*
1045 (remove-if-not #'cdr *delayed-ir1-transforms*))
1046 (let ((reoptimize nil))
1047 (dolist (assoc *delayed-ir1-transforms*)
1048 (let ((reasons (remove reason (cdr assoc))))
1049 (setf (cdr assoc) reasons)
1051 (let ((node (car assoc)))
1052 (unless (node-deleted node)
1054 (setf (node-reoptimize node) t)
1055 (let ((block (node-block node)))
1056 (setf (block-reoptimize block) t)
1057 (setf (component-reoptimize (block-component block)) t)))))))
1060 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1061 ;;; environment, and then install it as the function for the call
1062 ;;; NODE. We do local call analysis so that the new function is
1063 ;;; integrated into the control flow.
1065 ;;; We require the original function source name in order to generate
1066 ;;; a meaningful debug name for the lambda we set up. (It'd be
1067 ;;; possible to do this starting from debug names as well as source
1068 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1069 ;;; generality, since source names are always known to our callers.)
1070 (defun transform-call (call res source-name)
1071 (declare (type combination call) (list res))
1072 (aver (and (legal-fun-name-p source-name)
1073 (not (eql source-name '.anonymous.))))
1074 (node-ends-block call)
1075 (with-ir1-environment-from-node call
1076 (with-component-last-block (*current-component*
1077 (block-next (node-block call)))
1078 (let ((new-fun (ir1-convert-inline-lambda
1080 :debug-name (debug-namify "LAMBDA-inlined ~A"
1083 "<unknown function>"))))
1084 (ref (lvar-use (combination-fun call))))
1085 (change-ref-leaf ref new-fun)
1086 (setf (combination-kind call) :full)
1087 (locall-analyze-component *current-component*))))
1090 ;;; Replace a call to a foldable function of constant arguments with
1091 ;;; the result of evaluating the form. If there is an error during the
1092 ;;; evaluation, we give a warning and leave the call alone, making the
1093 ;;; call a :ERROR call.
1095 ;;; If there is more than one value, then we transform the call into a
1097 (defun constant-fold-call (call)
1098 (let ((args (mapcar #'lvar-value (combination-args call)))
1099 (fun-name (combination-fun-source-name call)))
1100 (multiple-value-bind (values win)
1101 (careful-call fun-name
1104 ;; Note: CMU CL had COMPILER-WARN here, and that
1105 ;; seems more natural, but it's probably not.
1107 ;; It's especially not while bug 173 exists:
1110 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1112 ;; can cause constant-folding TYPE-ERRORs (in
1113 ;; #'<=) when END can be proved to be NIL, even
1114 ;; though the code is perfectly legal and safe
1115 ;; because a NIL value of END means that the
1116 ;; #'<= will never be executed.
1118 ;; Moreover, even without bug 173,
1119 ;; quite-possibly-valid code like
1120 ;; (COND ((NONINLINED-PREDICATE END)
1121 ;; (UNLESS (<= END SIZE))
1123 ;; (where NONINLINED-PREDICATE is something the
1124 ;; compiler can't do at compile time, but which
1125 ;; turns out to make the #'<= expression
1126 ;; unreachable when END=NIL) could cause errors
1127 ;; when the compiler tries to constant-fold (<=
1130 ;; So, with or without bug 173, it'd be
1131 ;; unnecessarily evil to do a full
1132 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1133 ;; from COMPILE-FILE) for legal code, so we we
1134 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1135 #'compiler-style-warn
1138 (setf (combination-kind call) :error))
1139 ((and (proper-list-of-length-p values 1))
1140 (with-ir1-environment-from-node call
1141 (let* ((lvar (node-lvar call))
1142 (prev (node-prev call))
1143 (intermediate-ctran (make-ctran)))
1144 (%delete-lvar-use call)
1145 (setf (ctran-next prev) nil)
1146 (setf (node-prev call) nil)
1147 (reference-constant prev intermediate-ctran lvar
1149 (link-node-to-previous-ctran call intermediate-ctran)
1150 (reoptimize-lvar lvar)
1151 (flush-combination call))))
1152 (t (let ((dummies (make-gensym-list (length args))))
1156 (declare (ignore ,@dummies))
1157 (values ,@(mapcar (lambda (x) `',x) values)))
1161 ;;;; local call optimization
1163 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1164 ;;; the leaf type is a function type, then just leave it alone, since
1165 ;;; TYPE is never going to be more specific than that (and
1166 ;;; TYPE-INTERSECTION would choke.)
1167 (defun propagate-to-refs (leaf type)
1168 (declare (type leaf leaf) (type ctype type))
1169 (let ((var-type (leaf-type leaf)))
1170 (unless (fun-type-p var-type)
1171 (let ((int (type-approx-intersection2 var-type type)))
1172 (when (type/= int var-type)
1173 (setf (leaf-type leaf) int)
1174 (dolist (ref (leaf-refs leaf))
1175 (derive-node-type ref (make-single-value-type int))
1176 ;; KLUDGE: LET var substitution
1177 (let* ((lvar (node-lvar ref)))
1178 (when (and lvar (combination-p (lvar-dest lvar)))
1179 (reoptimize-lvar lvar))))))
1182 ;;; Iteration variable: exactly one SETQ of the form:
1184 ;;; (let ((var initial))
1186 ;;; (setq var (+ var step))
1188 (defun maybe-infer-iteration-var-type (var initial-type)
1189 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1191 (() (null (rest sets)) :exit-if-null)
1192 (set-use (principal-lvar-use (set-value set)))
1193 (() (and (combination-p set-use)
1194 (eq (combination-kind set-use) :known)
1195 (fun-info-p (combination-fun-info set-use))
1196 (not (node-to-be-deleted-p set-use))
1197 (eq (combination-fun-source-name set-use) '+))
1199 (+-args (basic-combination-args set-use))
1200 (() (and (proper-list-of-length-p +-args 2 2)
1201 (let ((first (principal-lvar-use
1204 (eq (ref-leaf first) var))))
1206 (step-type (lvar-type (second +-args)))
1207 (set-type (lvar-type (set-value set))))
1208 (when (and (numeric-type-p initial-type)
1209 (numeric-type-p step-type)
1210 (numeric-type-equal initial-type step-type))
1211 (multiple-value-bind (low high)
1212 (cond ((csubtypep step-type (specifier-type '(real 0 *)))
1213 (values (numeric-type-low initial-type)
1214 (when (and (numeric-type-p set-type)
1215 (numeric-type-equal set-type initial-type))
1216 (numeric-type-high set-type))))
1217 ((csubtypep step-type (specifier-type '(real * 0)))
1218 (values (when (and (numeric-type-p set-type)
1219 (numeric-type-equal set-type initial-type))
1220 (numeric-type-low set-type))
1221 (numeric-type-high initial-type)))
1224 (modified-numeric-type initial-type
1227 :enumerable nil)))))
1228 (deftransform + ((x y) * * :result result)
1229 "check for iteration variable reoptimization"
1230 (let ((dest (principal-lvar-end result))
1231 (use (principal-lvar-use x)))
1232 (when (and (ref-p use)
1236 (reoptimize-lvar (set-value dest))))
1237 (give-up-ir1-transform))
1239 ;;; Figure out the type of a LET variable that has sets. We compute
1240 ;;; the union of the INITIAL-TYPE and the types of all the set
1241 ;;; values and to a PROPAGATE-TO-REFS with this type.
1242 (defun propagate-from-sets (var initial-type)
1243 (collect ((res initial-type type-union))
1244 (dolist (set (basic-var-sets var))
1245 (let ((type (lvar-type (set-value set))))
1247 (when (node-reoptimize set)
1248 (derive-node-type set (make-single-value-type type))
1249 (setf (node-reoptimize set) nil))))
1251 (awhen (maybe-infer-iteration-var-type var initial-type)
1253 (propagate-to-refs var res)))
1256 ;;; If a LET variable, find the initial value's type and do
1257 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1259 (defun ir1-optimize-set (node)
1260 (declare (type cset node))
1261 (let ((var (set-var node)))
1262 (when (and (lambda-var-p var) (leaf-refs var))
1263 (let ((home (lambda-var-home var)))
1264 (when (eq (functional-kind home) :let)
1265 (let* ((initial-value (let-var-initial-value var))
1266 (initial-type (lvar-type initial-value)))
1267 (setf (lvar-reoptimize initial-value) nil)
1268 (propagate-from-sets var initial-type))))))
1270 (derive-node-type node (make-single-value-type
1271 (lvar-type (set-value node))))
1274 ;;; Return true if the value of REF will always be the same (and is
1275 ;;; thus legal to substitute.)
1276 (defun constant-reference-p (ref)
1277 (declare (type ref ref))
1278 (let ((leaf (ref-leaf ref)))
1280 ((or constant functional) t)
1282 (null (lambda-var-sets leaf)))
1284 (not (eq (defined-fun-inlinep leaf) :notinline)))
1286 (case (global-var-kind leaf)
1288 (let ((name (leaf-source-name leaf)))
1290 (eq (symbol-package (fun-name-block-name name))
1292 (info :function :info name)))))))))
1294 ;;; If we have a non-set LET var with a single use, then (if possible)
1295 ;;; replace the variable reference's LVAR with the arg lvar.
1297 ;;; We change the REF to be a reference to NIL with unused value, and
1298 ;;; let it be flushed as dead code. A side effect of this substitution
1299 ;;; is to delete the variable.
1300 (defun substitute-single-use-lvar (arg var)
1301 (declare (type lvar arg) (type lambda-var var))
1302 (binding* ((ref (first (leaf-refs var)))
1303 (lvar (node-lvar ref) :exit-if-null)
1304 (dest (lvar-dest lvar)))
1306 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1307 ;; LVAR-USEs should not be met on one path.
1308 (eq (lvar-uses lvar) ref)
1310 ;; we should not change lifetime of unknown values lvars
1312 (and (type-single-value-p (lvar-derived-type arg))
1313 (multiple-value-bind (pdest pprev)
1314 (principal-lvar-end lvar)
1315 (declare (ignore pdest))
1316 (lvar-single-value-p pprev))))
1318 (or (eq (basic-combination-fun dest) lvar)
1319 (and (eq (basic-combination-kind dest) :local)
1320 (type-single-value-p (lvar-derived-type arg)))))
1322 ;; While CRETURN and EXIT nodes may be known-values,
1323 ;; they have their own complications, such as
1324 ;; substitution into CRETURN may create new tail calls.
1327 (aver (lvar-single-value-p lvar))
1329 (eq (node-home-lambda ref)
1330 (lambda-home (lambda-var-home var))))
1331 (setf (node-derived-type ref) *wild-type*)
1332 (substitute-lvar-uses lvar arg)
1333 (delete-lvar-use ref)
1334 (change-ref-leaf ref (find-constant nil))
1337 (reoptimize-lvar lvar)
1340 ;;; Delete a LET, removing the call and bind nodes, and warning about
1341 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1342 ;;; along right away and delete the REF and then the lambda, since we
1343 ;;; flush the FUN lvar.
1344 (defun delete-let (clambda)
1345 (declare (type clambda clambda))
1346 (aver (functional-letlike-p clambda))
1347 (note-unreferenced-vars clambda)
1348 (let ((call (let-combination clambda)))
1349 (flush-dest (basic-combination-fun call))
1351 (unlink-node (lambda-bind clambda))
1352 (setf (lambda-bind clambda) nil))
1353 (setf (functional-kind clambda) :zombie)
1354 (let ((home (lambda-home clambda)))
1355 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1358 ;;; This function is called when one of the arguments to a LET
1359 ;;; changes. We look at each changed argument. If the corresponding
1360 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1361 ;;; consider substituting for the variable, and also propagate
1362 ;;; derived-type information for the arg to all the VAR's refs.
1364 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1365 ;;; subtype of the argument's leaf type. This prevents type checking
1366 ;;; from being defeated, and also ensures that the best representation
1367 ;;; for the variable can be used.
1369 ;;; Substitution of individual references is inhibited if the
1370 ;;; reference is in a different component from the home. This can only
1371 ;;; happen with closures over top level lambda vars. In such cases,
1372 ;;; the references may have already been compiled, and thus can't be
1373 ;;; retroactively modified.
1375 ;;; If all of the variables are deleted (have no references) when we
1376 ;;; are done, then we delete the LET.
1378 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1380 (defun propagate-let-args (call fun)
1381 (declare (type combination call) (type clambda fun))
1382 (loop for arg in (combination-args call)
1383 and var in (lambda-vars fun) do
1384 (when (and arg (lvar-reoptimize arg))
1385 (setf (lvar-reoptimize arg) nil)
1387 ((lambda-var-sets var)
1388 (propagate-from-sets var (lvar-type arg)))
1389 ((let ((use (lvar-uses arg)))
1391 (let ((leaf (ref-leaf use)))
1392 (when (and (constant-reference-p use)
1393 (csubtypep (leaf-type leaf)
1394 ;; (NODE-DERIVED-TYPE USE) would
1395 ;; be better -- APD, 2003-05-15
1397 (propagate-to-refs var (lvar-type arg))
1398 (let ((use-component (node-component use)))
1399 (prog1 (substitute-leaf-if
1401 (cond ((eq (node-component ref) use-component)
1404 (aver (lambda-toplevelish-p (lambda-home fun)))
1408 ((and (null (rest (leaf-refs var)))
1409 (substitute-single-use-lvar arg var)))
1411 (propagate-to-refs var (lvar-type arg))))))
1413 (when (every #'not (combination-args call))
1418 ;;; This function is called when one of the args to a non-LET local
1419 ;;; call changes. For each changed argument corresponding to an unset
1420 ;;; variable, we compute the union of the types across all calls and
1421 ;;; propagate this type information to the var's refs.
1423 ;;; If the function has an XEP, then we don't do anything, since we
1424 ;;; won't discover anything.
1426 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1427 ;;; corresponding to changed arguments in CALL, since the only use in
1428 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1430 (defun propagate-local-call-args (call fun)
1431 (declare (type combination call) (type clambda fun))
1433 (unless (or (functional-entry-fun fun)
1434 (lambda-optional-dispatch fun))
1435 (let* ((vars (lambda-vars fun))
1436 (union (mapcar (lambda (arg var)
1438 (lvar-reoptimize arg)
1439 (null (basic-var-sets var)))
1441 (basic-combination-args call)
1443 (this-ref (lvar-use (basic-combination-fun call))))
1445 (dolist (arg (basic-combination-args call))
1447 (setf (lvar-reoptimize arg) nil)))
1449 (dolist (ref (leaf-refs fun))
1450 (let ((dest (node-dest ref)))
1451 (unless (or (eq ref this-ref) (not dest))
1453 (mapcar (lambda (this-arg old)
1455 (setf (lvar-reoptimize this-arg) nil)
1456 (type-union (lvar-type this-arg) old)))
1457 (basic-combination-args dest)
1460 (loop for var in vars
1462 when type do (propagate-to-refs var type))))
1466 ;;;; multiple values optimization
1468 ;;; Do stuff to notice a change to a MV combination node. There are
1469 ;;; two main branches here:
1470 ;;; -- If the call is local, then it is already a MV let, or should
1471 ;;; become one. Note that although all :LOCAL MV calls must eventually
1472 ;;; be converted to :MV-LETs, there can be a window when the call
1473 ;;; is local, but has not been LET converted yet. This is because
1474 ;;; the entry-point lambdas may have stray references (in other
1475 ;;; entry points) that have not been deleted yet.
1476 ;;; -- The call is full. This case is somewhat similar to the non-MV
1477 ;;; combination optimization: we propagate return type information and
1478 ;;; notice non-returning calls. We also have an optimization
1479 ;;; which tries to convert MV-CALLs into MV-binds.
1480 (defun ir1-optimize-mv-combination (node)
1481 (ecase (basic-combination-kind node)
1483 (let ((fun-lvar (basic-combination-fun node)))
1484 (when (lvar-reoptimize fun-lvar)
1485 (setf (lvar-reoptimize fun-lvar) nil)
1486 (maybe-let-convert (combination-lambda node))))
1487 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1488 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1489 (unless (convert-mv-bind-to-let node)
1490 (ir1-optimize-mv-bind node))))
1492 (let* ((fun (basic-combination-fun node))
1493 (fun-changed (lvar-reoptimize fun))
1494 (args (basic-combination-args node)))
1496 (setf (lvar-reoptimize fun) nil)
1497 (let ((type (lvar-type fun)))
1498 (when (fun-type-p type)
1499 (derive-node-type node (fun-type-returns type))))
1500 (maybe-terminate-block node nil)
1501 (let ((use (lvar-uses fun)))
1502 (when (and (ref-p use) (functional-p (ref-leaf use)))
1503 (convert-call-if-possible use node)
1504 (when (eq (basic-combination-kind node) :local)
1505 (maybe-let-convert (ref-leaf use))))))
1506 (unless (or (eq (basic-combination-kind node) :local)
1507 (eq (lvar-fun-name fun) '%throw))
1508 (ir1-optimize-mv-call node))
1510 (setf (lvar-reoptimize arg) nil))))
1514 ;;; Propagate derived type info from the values lvar to the vars.
1515 (defun ir1-optimize-mv-bind (node)
1516 (declare (type mv-combination node))
1517 (let* ((arg (first (basic-combination-args node)))
1518 (vars (lambda-vars (combination-lambda node)))
1519 (n-vars (length vars))
1520 (types (values-type-in (lvar-derived-type arg)
1522 (loop for var in vars
1524 do (if (basic-var-sets var)
1525 (propagate-from-sets var type)
1526 (propagate-to-refs var type)))
1527 (setf (lvar-reoptimize arg) nil))
1530 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1532 ;;; -- The call has only one argument, and
1533 ;;; -- The function has a known fixed number of arguments, or
1534 ;;; -- The argument yields a known fixed number of values.
1536 ;;; What we do is change the function in the MV-CALL to be a lambda
1537 ;;; that "looks like an MV bind", which allows
1538 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1539 ;;; converted (the next time around.) This new lambda just calls the
1540 ;;; actual function with the MV-BIND variables as arguments. Note that
1541 ;;; this new MV bind is not let-converted immediately, as there are
1542 ;;; going to be stray references from the entry-point functions until
1543 ;;; they get deleted.
1545 ;;; In order to avoid loss of argument count checking, we only do the
1546 ;;; transformation according to a known number of expected argument if
1547 ;;; safety is unimportant. We can always convert if we know the number
1548 ;;; of actual values, since the normal call that we build will still
1549 ;;; do any appropriate argument count checking.
1551 ;;; We only attempt the transformation if the called function is a
1552 ;;; constant reference. This allows us to just splice the leaf into
1553 ;;; the new function, instead of trying to somehow bind the function
1554 ;;; expression. The leaf must be constant because we are evaluating it
1555 ;;; again in a different place. This also has the effect of squelching
1556 ;;; multiple warnings when there is an argument count error.
1557 (defun ir1-optimize-mv-call (node)
1558 (let ((fun (basic-combination-fun node))
1559 (*compiler-error-context* node)
1560 (ref (lvar-uses (basic-combination-fun node)))
1561 (args (basic-combination-args node)))
1563 (unless (and (ref-p ref) (constant-reference-p ref)
1565 (return-from ir1-optimize-mv-call))
1567 (multiple-value-bind (min max)
1568 (fun-type-nargs (lvar-type fun))
1570 (multiple-value-bind (types nvals)
1571 (values-types (lvar-derived-type (first args)))
1572 (declare (ignore types))
1573 (if (eq nvals :unknown) nil nvals))))
1576 (when (and min (< total-nvals min))
1578 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1581 (setf (basic-combination-kind node) :error)
1582 (return-from ir1-optimize-mv-call))
1583 (when (and max (> total-nvals max))
1585 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1588 (setf (basic-combination-kind node) :error)
1589 (return-from ir1-optimize-mv-call)))
1591 (let ((count (cond (total-nvals)
1592 ((and (policy node (zerop verify-arg-count))
1597 (with-ir1-environment-from-node node
1598 (let* ((dums (make-gensym-list count))
1600 (fun (ir1-convert-lambda
1601 `(lambda (&optional ,@dums &rest ,ignore)
1602 (declare (ignore ,ignore))
1603 (funcall ,(ref-leaf ref) ,@dums)))))
1604 (change-ref-leaf ref fun)
1605 (aver (eq (basic-combination-kind node) :full))
1606 (locall-analyze-component *current-component*)
1607 (aver (eq (basic-combination-kind node) :local)))))))))
1611 ;;; (multiple-value-bind
1620 ;;; What we actually do is convert the VALUES combination into a
1621 ;;; normal LET combination calling the original :MV-LET lambda. If
1622 ;;; there are extra args to VALUES, discard the corresponding
1623 ;;; lvars. If there are insufficient args, insert references to NIL.
1624 (defun convert-mv-bind-to-let (call)
1625 (declare (type mv-combination call))
1626 (let* ((arg (first (basic-combination-args call)))
1627 (use (lvar-uses arg)))
1628 (when (and (combination-p use)
1629 (eq (lvar-fun-name (combination-fun use))
1631 (let* ((fun (combination-lambda call))
1632 (vars (lambda-vars fun))
1633 (vals (combination-args use))
1634 (nvars (length vars))
1635 (nvals (length vals)))
1636 (cond ((> nvals nvars)
1637 (mapc #'flush-dest (subseq vals nvars))
1638 (setq vals (subseq vals 0 nvars)))
1640 (with-ir1-environment-from-node use
1641 (let ((node-prev (node-prev use)))
1642 (setf (node-prev use) nil)
1643 (setf (ctran-next node-prev) nil)
1644 (collect ((res vals))
1645 (loop for count below (- nvars nvals)
1646 for prev = node-prev then ctran
1647 for ctran = (make-ctran)
1648 and lvar = (make-lvar use)
1649 do (reference-constant prev ctran lvar nil)
1651 finally (link-node-to-previous-ctran
1653 (setq vals (res)))))))
1654 (setf (combination-args use) vals)
1655 (flush-dest (combination-fun use))
1656 (let ((fun-lvar (basic-combination-fun call)))
1657 (setf (lvar-dest fun-lvar) use)
1658 (setf (combination-fun use) fun-lvar)
1659 (flush-lvar-externally-checkable-type fun-lvar))
1660 (setf (combination-kind use) :local)
1661 (setf (functional-kind fun) :let)
1662 (flush-dest (first (basic-combination-args call)))
1665 (reoptimize-lvar (first vals)))
1666 (propagate-to-args use fun)
1667 (reoptimize-call use))
1671 ;;; (values-list (list x y z))
1676 ;;; In implementation, this is somewhat similar to
1677 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1678 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1679 ;;; (allowing the LIST to be flushed.)
1681 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1682 (defoptimizer (values-list optimizer) ((list) node)
1683 (let ((use (lvar-uses list)))
1684 (when (and (combination-p use)
1685 (eq (lvar-fun-name (combination-fun use))
1688 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1689 (change-ref-leaf (lvar-uses (combination-fun node))
1690 (find-free-fun 'values "in a strange place"))
1691 (setf (combination-kind node) :full)
1692 (let ((args (combination-args use)))
1694 (setf (lvar-dest arg) node)
1695 (flush-lvar-externally-checkable-type arg))
1696 (setf (combination-args use) nil)
1698 (setf (combination-args node) args))
1701 ;;; If VALUES appears in a non-MV context, then effectively convert it
1702 ;;; to a PROG1. This allows the computation of the additional values
1703 ;;; to become dead code.
1704 (deftransform values ((&rest vals) * * :node node)
1705 (unless (lvar-single-value-p (node-lvar node))
1706 (give-up-ir1-transform))
1707 (setf (node-derived-type node)
1708 (make-short-values-type (list (single-value-type
1709 (node-derived-type node)))))
1710 (principal-lvar-single-valuify (node-lvar node))
1712 (let ((dummies (make-gensym-list (length (cdr vals)))))
1713 `(lambda (val ,@dummies)
1714 (declare (ignore ,@dummies))
1720 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1721 (declare (type cast cast))
1722 (let ((value (cast-value cast))
1723 (atype (cast-asserted-type cast)))
1724 (when (not do-not-optimize)
1725 (let ((lvar (node-lvar cast)))
1726 (when (values-subtypep (lvar-derived-type value)
1727 (cast-asserted-type cast))
1728 (delete-filter cast lvar value)
1730 (reoptimize-lvar lvar)
1731 (when (lvar-single-value-p lvar)
1732 (note-single-valuified-lvar lvar)))
1733 (return-from ir1-optimize-cast t))
1735 (when (and (listp (lvar-uses value))
1737 ;; Pathwise removing of CAST
1738 (let ((ctran (node-next cast))
1739 (dest (lvar-dest lvar))
1742 (do-uses (use value)
1743 (when (and (values-subtypep (node-derived-type use) atype)
1744 (immediately-used-p value use))
1746 (when ctran (ensure-block-start ctran))
1747 (setq next-block (first (block-succ (node-block cast))))
1748 (ensure-block-start (node-prev cast)))
1749 (%delete-lvar-use use)
1750 (add-lvar-use use lvar)
1751 (unlink-blocks (node-block use) (node-block cast))
1752 (link-blocks (node-block use) next-block)
1753 (when (and (return-p dest)
1754 (basic-combination-p use)
1755 (eq (basic-combination-kind use) :local))
1757 (dolist (use (merges))
1758 (merge-tail-sets use)))))))
1760 (let* ((value-type (lvar-derived-type value))
1761 (int (values-type-intersection value-type atype)))
1762 (derive-node-type cast int)
1763 (when (eq int *empty-type*)
1764 (unless (eq value-type *empty-type*)
1766 ;; FIXME: Do it in one step.
1769 `(multiple-value-call #'list 'dummy))
1772 ;; FIXME: Derived type.
1773 `(%compile-time-type-error 'dummy
1774 ',(type-specifier atype)
1775 ',(type-specifier value-type)))
1776 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1777 ;; functions, so we declare the return type of
1778 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1780 (setq value (cast-value cast))
1781 (derive-node-type (lvar-uses value) *empty-type*)
1782 (maybe-terminate-block (lvar-uses value) nil)
1783 ;; FIXME: Is it necessary?
1784 (aver (null (block-pred (node-block cast))))
1785 (delete-block-lazily (node-block cast))
1786 (return-from ir1-optimize-cast)))
1787 (when (eq (node-derived-type cast) *empty-type*)
1788 (maybe-terminate-block cast nil))
1790 (when (and (cast-%type-check cast)
1791 (values-subtypep value-type
1792 (cast-type-to-check cast)))
1793 (setf (cast-%type-check cast) nil))))
1795 (unless do-not-optimize
1796 (setf (node-reoptimize cast) nil)))