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)
344 (consp (lvar-uses it))))))
347 (join-blocks block next)
350 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
351 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
352 ;;; for the two blocks so that any indicated optimization gets done.
353 (defun join-blocks (block1 block2)
354 (declare (type cblock block1 block2))
355 (let* ((last1 (block-last block1))
356 (last2 (block-last block2))
357 (succ (block-succ block2))
358 (start2 (block-start block2)))
359 (do ((ctran start2 (node-next (ctran-next ctran))))
361 (setf (ctran-block ctran) block1))
363 (unlink-blocks block1 block2)
365 (unlink-blocks block2 block)
366 (link-blocks block1 block))
368 (setf (ctran-kind start2) :inside-block)
369 (setf (node-next last1) start2)
370 (setf (ctran-use start2) last1)
371 (setf (block-last block1) last2))
373 (setf (block-flags block1)
374 (attributes-union (block-flags block1)
376 (block-attributes type-asserted test-modified)))
378 (let ((next (block-next block2))
379 (prev (block-prev block2)))
380 (setf (block-next prev) next)
381 (setf (block-prev next) prev))
385 ;;; Delete any nodes in BLOCK whose value is unused and which have no
386 ;;; side effects. We can delete sets of lexical variables when the set
387 ;;; variable has no references.
388 (defun flush-dead-code (block)
389 (declare (type cblock block))
390 (setf (block-flush-p block) nil)
391 (do-nodes-backwards (node lvar block :restart-p t)
398 (let ((kind (combination-kind node))
399 (info (combination-fun-info node)))
400 (when (and (eq kind :known) (fun-info-p info))
401 (let ((attr (fun-info-attributes info)))
402 (when (and (not (ir1-attributep attr call))
403 ;; ### For now, don't delete potentially
404 ;; flushable calls when they have the CALL
405 ;; attribute. Someday we should look at the
406 ;; functional args to determine if they have
408 (if (policy node (= safety 3))
409 (ir1-attributep attr flushable)
410 (ir1-attributep attr unsafely-flushable)))
411 (flush-combination node))))))
413 (when (eq (basic-combination-kind node) :local)
414 (let ((fun (combination-lambda node)))
415 (when (dolist (var (lambda-vars fun) t)
416 (when (or (leaf-refs var)
417 (lambda-var-sets var))
419 (flush-dest (first (basic-combination-args node)))
422 (let ((value (exit-value node)))
425 (setf (exit-value node) nil))))
427 (let ((var (set-var node)))
428 (when (and (lambda-var-p var)
429 (null (leaf-refs var)))
430 (flush-dest (set-value node))
431 (setf (basic-var-sets var)
432 (delq node (basic-var-sets var)))
433 (unlink-node node))))
435 (unless (cast-type-check node)
436 (flush-dest (cast-value node))
437 (unlink-node node))))))
441 ;;;; local call return type propagation
443 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
444 ;;; flag set. It iterates over the uses of the RESULT, looking for
445 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
446 ;;; call, then we union its type together with the types of other such
447 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
448 ;;; type with the RESULT's asserted type. We can make this
449 ;;; intersection now (potentially before type checking) because this
450 ;;; assertion on the result will eventually be checked (if
453 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
454 ;;; combination, which may change the succesor of the call to be the
455 ;;; called function, and if so, checks if the call can become an
456 ;;; assignment. If we convert to an assignment, we abort, since the
457 ;;; RETURN has been deleted.
458 (defun find-result-type (node)
459 (declare (type creturn node))
460 (let ((result (return-result node)))
461 (collect ((use-union *empty-type* values-type-union))
462 (do-uses (use result)
463 (let ((use-home (node-home-lambda use)))
464 (cond ((or (eq (functional-kind use-home) :deleted)
465 (block-delete-p (node-block use))))
466 ((and (basic-combination-p use)
467 (eq (basic-combination-kind use) :local))
468 (aver (eq (lambda-tail-set use-home)
469 (lambda-tail-set (combination-lambda use))))
470 (when (combination-p use)
471 (when (nth-value 1 (maybe-convert-tail-local-call use))
472 (return-from find-result-type t))))
474 (use-union (node-derived-type use))))))
476 ;; (values-type-intersection
477 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
481 (setf (return-result-type node) int))))
484 ;;; Do stuff to realize that something has changed about the value
485 ;;; delivered to a return node. Since we consider the return values of
486 ;;; all functions in the tail set to be equivalent, this amounts to
487 ;;; bringing the entire tail set up to date. We iterate over the
488 ;;; returns for all the functions in the tail set, reanalyzing them
489 ;;; all (not treating NODE specially.)
491 ;;; When we are done, we check whether the new type is different from
492 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
493 ;;; all the lvars for references to functions in the tail set. This
494 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
495 ;;; results of the calls.
496 (defun ir1-optimize-return (node)
497 (declare (type creturn node))
500 (let* ((tails (lambda-tail-set (return-lambda node)))
501 (funs (tail-set-funs tails)))
502 (collect ((res *empty-type* values-type-union))
504 (let ((return (lambda-return fun)))
506 (when (node-reoptimize return)
507 (setf (node-reoptimize return) nil)
508 (when (find-result-type return)
510 (res (return-result-type return)))))
512 (when (type/= (res) (tail-set-type tails))
513 (setf (tail-set-type tails) (res))
514 (dolist (fun (tail-set-funs tails))
515 (dolist (ref (leaf-refs fun))
516 (reoptimize-lvar (node-lvar ref))))))))
522 ;;; If the test has multiple uses, replicate the node when possible.
523 ;;; Also check whether the predicate is known to be true or false,
524 ;;; deleting the IF node in favor of the appropriate branch when this
526 (defun ir1-optimize-if (node)
527 (declare (type cif node))
528 (let ((test (if-test node))
529 (block (node-block node)))
531 (when (and (eq (block-start-node block) node)
532 (listp (lvar-uses test)))
534 (when (immediately-used-p test use)
535 (convert-if-if use node)
536 (when (not (listp (lvar-uses test))) (return)))))
538 (let* ((type (lvar-type test))
540 (cond ((constant-lvar-p test)
541 (if (lvar-value test)
542 (if-alternative node)
543 (if-consequent node)))
544 ((not (types-equal-or-intersect type (specifier-type 'null)))
545 (if-alternative node))
546 ((type= type (specifier-type 'null))
547 (if-consequent node)))))
550 (when (rest (block-succ block))
551 (unlink-blocks block victim))
552 (setf (component-reanalyze (node-component node)) t)
553 (unlink-node node))))
556 ;;; Create a new copy of an IF node that tests the value of the node
557 ;;; USE. The test must have >1 use, and must be immediately used by
558 ;;; USE. NODE must be the only node in its block (implying that
559 ;;; block-start = if-test).
561 ;;; This optimization has an effect semantically similar to the
562 ;;; source-to-source transformation:
563 ;;; (IF (IF A B C) D E) ==>
564 ;;; (IF A (IF B D E) (IF C D E))
566 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
567 ;;; node so that dead code deletion notes will definitely not consider
568 ;;; either node to be part of the original source. One node might
569 ;;; become unreachable, resulting in a spurious note.
570 (defun convert-if-if (use node)
571 (declare (type node use) (type cif node))
572 (with-ir1-environment-from-node node
573 (let* ((block (node-block node))
574 (test (if-test node))
575 (cblock (if-consequent node))
576 (ablock (if-alternative node))
577 (use-block (node-block use))
578 (new-ctran (make-ctran))
579 (new-lvar (make-lvar))
580 (new-node (make-if :test new-lvar
582 :alternative ablock))
583 (new-block (ctran-starts-block new-ctran)))
584 (link-node-to-previous-ctran new-node new-ctran)
585 (setf (lvar-dest new-lvar) new-node)
586 (setf (block-last new-block) new-node)
588 (unlink-blocks use-block block)
589 (%delete-lvar-use use)
590 (add-lvar-use use new-lvar)
591 (link-blocks use-block new-block)
593 (link-blocks new-block cblock)
594 (link-blocks new-block ablock)
596 (push "<IF Duplication>" (node-source-path node))
597 (push "<IF Duplication>" (node-source-path new-node))
599 (reoptimize-lvar test)
600 (reoptimize-lvar new-lvar)
601 (setf (component-reanalyze *current-component*) t)))
604 ;;;; exit IR1 optimization
606 ;;; This function attempts to delete an exit node, returning true if
607 ;;; it deletes the block as a consequence:
608 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
609 ;;; anything, since there is nothing to be done.
610 ;;; -- If the exit node and its ENTRY have the same home lambda then
611 ;;; we know the exit is local, and can delete the exit. We change
612 ;;; uses of the Exit-Value to be uses of the original lvar,
613 ;;; then unlink the node. If the exit is to a TR context, then we
614 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
615 ;;; their value to this exit.
616 ;;; -- If there is no value (as in a GO), then we skip the value
619 ;;; This function is also called by environment analysis, since it
620 ;;; wants all exits to be optimized even if normal optimization was
622 (defun maybe-delete-exit (node)
623 (declare (type exit node))
624 (let ((value (exit-value node))
625 (entry (exit-entry node)))
627 (eq (node-home-lambda node) (node-home-lambda entry)))
628 (setf (entry-exits entry) (delq node (entry-exits entry)))
630 (delete-filter node (node-lvar node) value)
631 (unlink-node node)))))
634 ;;;; combination IR1 optimization
636 ;;; Report as we try each transform?
638 (defvar *show-transforms-p* nil)
640 ;;; Do IR1 optimizations on a COMBINATION node.
641 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
642 (defun ir1-optimize-combination (node)
643 (when (lvar-reoptimize (basic-combination-fun node))
644 (propagate-fun-change node)
645 (maybe-terminate-block node nil))
646 (let ((args (basic-combination-args node))
647 (kind (basic-combination-kind node))
648 (info (basic-combination-fun-info node)))
651 (let ((fun (combination-lambda node)))
652 (if (eq (functional-kind fun) :let)
653 (propagate-let-args node fun)
654 (propagate-local-call-args node fun))))
658 (setf (lvar-reoptimize arg) nil))))
662 (setf (lvar-reoptimize arg) nil)))
664 (let ((fun (fun-info-derive-type info)))
666 (let ((res (funcall fun node)))
668 (derive-node-type node (coerce-to-values res))
669 (maybe-terminate-block node nil)))))))
674 (setf (lvar-reoptimize arg) nil)))
676 (let ((attr (fun-info-attributes info)))
677 (when (and (ir1-attributep attr foldable)
678 ;; KLUDGE: The next test could be made more sensitive,
679 ;; only suppressing constant-folding of functions with
680 ;; CALL attributes when they're actually passed
681 ;; function arguments. -- WHN 19990918
682 (not (ir1-attributep attr call))
683 (every #'constant-lvar-p args)
685 ;; Even if the function is foldable in principle,
686 ;; it might be one of our low-level
687 ;; implementation-specific functions. Such
688 ;; functions don't necessarily exist at runtime on
689 ;; a plain vanilla ANSI Common Lisp
690 ;; cross-compilation host, in which case the
691 ;; cross-compiler can't fold it because the
692 ;; cross-compiler doesn't know how to evaluate it.
694 (or (fboundp (combination-fun-source-name node))
695 (progn (format t ";;; !!! Unbound fun: (~S~{ ~S~})~%"
696 (combination-fun-source-name node)
697 (mapcar #'lvar-value args))
699 (constant-fold-call node)
700 (return-from ir1-optimize-combination)))
702 (let ((fun (fun-info-derive-type info)))
704 (let ((res (funcall fun node)))
706 (derive-node-type node (coerce-to-values res))
707 (maybe-terminate-block node nil)))))
709 (let ((fun (fun-info-optimizer info)))
710 (unless (and fun (funcall fun node))
711 (dolist (x (fun-info-transforms info))
713 (when *show-transforms-p*
714 (let* ((lvar (basic-combination-fun node))
715 (fname (lvar-fun-name lvar t)))
716 (/show "trying transform" x (transform-function x) "for" fname)))
717 (unless (ir1-transform node x)
719 (when *show-transforms-p*
720 (/show "quitting because IR1-TRANSFORM result was NIL"))
725 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
726 ;;; the block there, and link it to the component tail.
728 ;;; Except when called during IR1 convertion, we delete the
729 ;;; continuation if it has no other uses. (If it does have other uses,
732 ;;; Termination on the basis of a continuation type is
734 ;;; -- The continuation is deleted (hence the assertion is spurious), or
735 ;;; -- We are in IR1 conversion (where THE assertions are subject to
736 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
737 ;;; uses can(?) be added later. -- APD, 2003-07-17
739 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
740 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
741 (declare (type (or basic-combination cast) node))
742 (let* ((block (node-block node))
743 (lvar (node-lvar node))
744 (ctran (node-next node))
745 (tail (component-tail (block-component block)))
746 (succ (first (block-succ block))))
747 (declare (ignore lvar))
748 (unless (or (and (eq node (block-last block)) (eq succ tail))
749 (block-delete-p block))
750 (when (eq (node-derived-type node) *empty-type*)
751 (cond (ir1-converting-not-optimizing-p
754 (aver (eq (block-last block) node)))
756 (setf (block-last block) node)
757 (setf (ctran-use ctran) nil)
758 (setf (ctran-kind ctran) :unused)
759 (setf (ctran-block ctran) nil)
760 (setf (node-next node) nil)
761 (link-blocks block (ctran-starts-block ctran)))))
763 (node-ends-block node)))
765 (unlink-blocks block (first (block-succ block)))
766 (setf (component-reanalyze (block-component block)) t)
767 (aver (not (block-succ block)))
768 (link-blocks block tail)
769 (if ir1-converting-not-optimizing-p
770 (%delete-lvar-use node)
771 (delete-lvar-use node))
774 ;;; This is called both by IR1 conversion and IR1 optimization when
775 ;;; they have verified the type signature for the call, and are
776 ;;; wondering if something should be done to special-case the call. If
777 ;;; CALL is a call to a global function, then see whether it defined
779 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
780 ;;; the expansion and change the call to call it. Expansion is
781 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
782 ;;; true, we never expand, since this function has already been
783 ;;; converted. Local call analysis will duplicate the definition
784 ;;; if necessary. We claim that the parent form is LABELS for
785 ;;; context declarations, since we don't want it to be considered
786 ;;; a real global function.
787 ;;; -- If it is a known function, mark it as such by setting the KIND.
789 ;;; We return the leaf referenced (NIL if not a leaf) and the
790 ;;; FUN-INFO assigned.
791 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
792 (declare (type combination call))
793 (let* ((ref (lvar-uses (basic-combination-fun call)))
794 (leaf (when (ref-p ref) (ref-leaf ref)))
795 (inlinep (if (defined-fun-p leaf)
796 (defined-fun-inlinep leaf)
799 ((eq inlinep :notinline)
800 (let ((info (info :function :info (leaf-source-name leaf))))
802 (setf (basic-combination-fun-info call) info))
804 ((not (and (global-var-p leaf)
805 (eq (global-var-kind leaf) :global-function)))
810 ((nil :maybe-inline) (policy call (zerop space))))
812 (defined-fun-inline-expansion leaf)
813 (let ((fun (defined-fun-functional leaf)))
815 (and (eq inlinep :inline) (functional-kind fun))))
816 (inline-expansion-ok call))
817 (flet (;; FIXME: Is this what the old CMU CL internal documentation
818 ;; called semi-inlining? A more descriptive name would
819 ;; be nice. -- WHN 2002-01-07
821 (let ((res (ir1-convert-lambda-for-defun
822 (defined-fun-inline-expansion leaf)
824 #'ir1-convert-inline-lambda)))
825 (setf (defined-fun-functional leaf) res)
826 (change-ref-leaf ref res))))
827 (if ir1-converting-not-optimizing-p
829 (with-ir1-environment-from-node call
831 (locall-analyze-component *current-component*))))
833 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
836 (let ((info (info :function :info (leaf-source-name leaf))))
840 (setf (basic-combination-kind call) :known)
841 (setf (basic-combination-fun-info call) info)))
842 (values leaf nil)))))))
844 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
845 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
846 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
847 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
848 ;;; syntax check, arg/result type processing, but still call
849 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
850 ;;; and that checking is done by local call analysis.
851 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
852 (declare (type combination call) (type ctype type))
853 (cond ((not (fun-type-p type))
854 (aver (multiple-value-bind (val win)
855 (csubtypep type (specifier-type 'function))
857 (recognize-known-call call ir1-converting-not-optimizing-p))
858 ((valid-fun-use call type
859 :argument-test #'always-subtypep
861 ;; KLUDGE: Common Lisp is such a dynamic
862 ;; language that all we can do here in
863 ;; general is issue a STYLE-WARNING. It
864 ;; would be nice to issue a full WARNING
865 ;; in the special case of of type
866 ;; mismatches within a compilation unit
867 ;; (as in section 3.2.2.3 of the spec)
868 ;; but at least as of sbcl-0.6.11, we
869 ;; don't keep track of whether the
870 ;; mismatched data came from the same
871 ;; compilation unit, so we can't do that.
874 ;; FIXME: Actually, I think we could
875 ;; issue a full WARNING if the call
876 ;; violates a DECLAIM FTYPE.
877 :lossage-fun #'compiler-style-warn
878 :unwinnage-fun #'compiler-notify)
879 (assert-call-type call type)
880 (maybe-terminate-block call ir1-converting-not-optimizing-p)
881 (recognize-known-call call ir1-converting-not-optimizing-p))
883 (setf (combination-kind call) :error)
886 ;;; This is called by IR1-OPTIMIZE when the function for a call has
887 ;;; changed. If the call is local, we try to LET-convert it, and
888 ;;; derive the result type. If it is a :FULL call, we validate it
889 ;;; against the type, which recognizes known calls, does inline
890 ;;; expansion, etc. If a call to a predicate in a non-conditional
891 ;;; position or to a function with a source transform, then we
892 ;;; reconvert the form to give IR1 another chance.
893 (defun propagate-fun-change (call)
894 (declare (type combination call))
895 (let ((*compiler-error-context* call)
896 (fun-lvar (basic-combination-fun call)))
897 (setf (lvar-reoptimize fun-lvar) nil)
898 (case (combination-kind call)
900 (let ((fun (combination-lambda call)))
901 (maybe-let-convert fun)
902 (unless (member (functional-kind fun) '(:let :assignment :deleted))
903 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
905 (multiple-value-bind (leaf info)
906 (validate-call-type call (lvar-type fun-lvar) nil)
907 (cond ((functional-p leaf)
908 (convert-call-if-possible
909 (lvar-uses (basic-combination-fun call))
912 ((and (global-var-p leaf)
913 (eq (global-var-kind leaf) :global-function)
914 (leaf-has-source-name-p leaf)
915 (or (info :function :source-transform (leaf-source-name leaf))
917 (ir1-attributep (fun-info-attributes info)
919 (let ((lvar (node-lvar call)))
920 (and lvar (not (if-p (lvar-dest lvar))))))))
921 (let ((name (leaf-source-name leaf))
922 (dummies (make-gensym-list
923 (length (combination-args call)))))
926 (,@(if (symbolp name)
930 (leaf-source-name leaf)))))))))
933 ;;;; known function optimization
935 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
936 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
937 ;;; replace it, otherwise add a new one.
938 (defun record-optimization-failure (node transform args)
939 (declare (type combination node) (type transform transform)
940 (type (or fun-type list) args))
941 (let* ((table (component-failed-optimizations *component-being-compiled*))
942 (found (assoc transform (gethash node table))))
944 (setf (cdr found) args)
945 (push (cons transform args) (gethash node table))))
948 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
949 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
950 ;;; doing the transform for some reason and FLAME is true, then we
951 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
952 ;;; finalize to pick up. We return true if the transform failed, and
953 ;;; thus further transformation should be attempted. We return false
954 ;;; if either the transform succeeded or was aborted.
955 (defun ir1-transform (node transform)
956 (declare (type combination node) (type transform transform))
957 (let* ((type (transform-type transform))
958 (fun (transform-function transform))
959 (constrained (fun-type-p type))
960 (table (component-failed-optimizations *component-being-compiled*))
961 (flame (if (transform-important transform)
962 (policy node (>= speed inhibit-warnings))
963 (policy node (> speed inhibit-warnings))))
964 (*compiler-error-context* node))
965 (cond ((or (not constrained)
966 (valid-fun-use node type))
967 (multiple-value-bind (severity args)
968 (catch 'give-up-ir1-transform
971 (combination-fun-source-name node))
978 (setf (combination-kind node) :error)
986 (record-optimization-failure node transform args))
987 (setf (gethash node table)
988 (remove transform (gethash node table) :key #'car)))
996 :argument-test #'types-equal-or-intersect
997 :result-test #'values-types-equal-or-intersect))
998 (record-optimization-failure node transform type)
1003 ;;; When we don't like an IR1 transform, we throw the severity/reason
1006 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1007 ;;; aborting this attempt to transform the call, but admitting the
1008 ;;; possibility that this or some other transform will later succeed.
1009 ;;; If arguments are supplied, they are format arguments for an
1010 ;;; efficiency note.
1012 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1013 ;;; force a normal call to the function at run time. No further
1014 ;;; optimizations will be attempted.
1016 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1017 ;;; delay the transform on the node until later. REASONS specifies
1018 ;;; when the transform will be later retried. The :OPTIMIZE reason
1019 ;;; causes the transform to be delayed until after the current IR1
1020 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1021 ;;; be delayed until after constraint propagation.
1023 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1024 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1025 ;;; do CASE operations on the various REASON values, it might be a
1026 ;;; good idea to go OO, representing the reasons by objects, using
1027 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1028 ;;; SIGNAL instead of THROW.
1029 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1030 (defun give-up-ir1-transform (&rest args)
1031 (throw 'give-up-ir1-transform (values :failure args)))
1032 (defun abort-ir1-transform (&rest args)
1033 (throw 'give-up-ir1-transform (values :aborted args)))
1034 (defun delay-ir1-transform (node &rest reasons)
1035 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1037 (setf *delayed-ir1-transforms*
1038 (acons node reasons *delayed-ir1-transforms*))
1039 (throw 'give-up-ir1-transform :delayed))
1041 (dolist (reason reasons)
1042 (pushnew reason (cdr assoc)))
1043 (throw 'give-up-ir1-transform :delayed)))))
1045 ;;; Clear any delayed transform with no reasons - these should have
1046 ;;; been tried in the last pass. Then remove the reason from the
1047 ;;; delayed transform reasons, and if any become empty then set
1048 ;;; reoptimize flags for the node. Return true if any transforms are
1050 (defun retry-delayed-ir1-transforms (reason)
1051 (setf *delayed-ir1-transforms*
1052 (remove-if-not #'cdr *delayed-ir1-transforms*))
1053 (let ((reoptimize nil))
1054 (dolist (assoc *delayed-ir1-transforms*)
1055 (let ((reasons (remove reason (cdr assoc))))
1056 (setf (cdr assoc) reasons)
1058 (let ((node (car assoc)))
1059 (unless (node-deleted node)
1061 (setf (node-reoptimize node) t)
1062 (let ((block (node-block node)))
1063 (setf (block-reoptimize block) t)
1064 (setf (component-reoptimize (block-component block)) t)))))))
1067 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1068 ;;; environment, and then install it as the function for the call
1069 ;;; NODE. We do local call analysis so that the new function is
1070 ;;; integrated into the control flow.
1072 ;;; We require the original function source name in order to generate
1073 ;;; a meaningful debug name for the lambda we set up. (It'd be
1074 ;;; possible to do this starting from debug names as well as source
1075 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1076 ;;; generality, since source names are always known to our callers.)
1077 (defun transform-call (call res source-name)
1078 (declare (type combination call) (list res))
1079 (aver (and (legal-fun-name-p source-name)
1080 (not (eql source-name '.anonymous.))))
1081 (node-ends-block call)
1082 (with-ir1-environment-from-node call
1083 (with-component-last-block (*current-component*
1084 (block-next (node-block call)))
1085 (let ((new-fun (ir1-convert-inline-lambda
1087 :debug-name (debug-namify "LAMBDA-inlined "
1089 "<unknown function>")))
1090 (ref (lvar-use (combination-fun call))))
1091 (change-ref-leaf ref new-fun)
1092 (setf (combination-kind call) :full)
1093 (locall-analyze-component *current-component*))))
1096 ;;; Replace a call to a foldable function of constant arguments with
1097 ;;; the result of evaluating the form. If there is an error during the
1098 ;;; evaluation, we give a warning and leave the call alone, making the
1099 ;;; call a :ERROR call.
1101 ;;; If there is more than one value, then we transform the call into a
1103 (defun constant-fold-call (call)
1104 (let ((args (mapcar #'lvar-value (combination-args call)))
1105 (fun-name (combination-fun-source-name call)))
1106 (multiple-value-bind (values win)
1107 (careful-call fun-name
1110 ;; Note: CMU CL had COMPILER-WARN here, and that
1111 ;; seems more natural, but it's probably not.
1113 ;; It's especially not while bug 173 exists:
1116 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1118 ;; can cause constant-folding TYPE-ERRORs (in
1119 ;; #'<=) when END can be proved to be NIL, even
1120 ;; though the code is perfectly legal and safe
1121 ;; because a NIL value of END means that the
1122 ;; #'<= will never be executed.
1124 ;; Moreover, even without bug 173,
1125 ;; quite-possibly-valid code like
1126 ;; (COND ((NONINLINED-PREDICATE END)
1127 ;; (UNLESS (<= END SIZE))
1129 ;; (where NONINLINED-PREDICATE is something the
1130 ;; compiler can't do at compile time, but which
1131 ;; turns out to make the #'<= expression
1132 ;; unreachable when END=NIL) could cause errors
1133 ;; when the compiler tries to constant-fold (<=
1136 ;; So, with or without bug 173, it'd be
1137 ;; unnecessarily evil to do a full
1138 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1139 ;; from COMPILE-FILE) for legal code, so we we
1140 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1141 #'compiler-style-warn
1144 (setf (combination-kind call) :error))
1145 ((and (proper-list-of-length-p values 1))
1146 (with-ir1-environment-from-node call
1147 (let* ((lvar (node-lvar call))
1148 (prev (node-prev call))
1149 (intermediate-ctran (make-ctran)))
1150 (%delete-lvar-use call)
1151 (setf (ctran-next prev) nil)
1152 (setf (node-prev call) nil)
1153 (reference-constant prev intermediate-ctran lvar
1155 (link-node-to-previous-ctran call intermediate-ctran)
1156 (reoptimize-lvar lvar)
1157 (flush-combination call))))
1158 (t (let ((dummies (make-gensym-list (length args))))
1162 (declare (ignore ,@dummies))
1163 (values ,@(mapcar (lambda (x) `',x) values)))
1167 ;;;; local call optimization
1169 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1170 ;;; the leaf type is a function type, then just leave it alone, since
1171 ;;; TYPE is never going to be more specific than that (and
1172 ;;; TYPE-INTERSECTION would choke.)
1173 (defun propagate-to-refs (leaf type)
1174 (declare (type leaf leaf) (type ctype type))
1175 (let ((var-type (leaf-type leaf)))
1176 (unless (fun-type-p var-type)
1177 (let ((int (type-approx-intersection2 var-type type)))
1178 (when (type/= int var-type)
1179 (setf (leaf-type leaf) int)
1180 (dolist (ref (leaf-refs leaf))
1181 (derive-node-type ref (make-single-value-type int))
1182 ;; KLUDGE: LET var substitution
1183 (let* ((lvar (node-lvar ref)))
1184 (when (and lvar (combination-p (lvar-dest lvar)))
1185 (reoptimize-lvar lvar))))))
1188 ;;; Iteration variable: exactly one SETQ of the form:
1190 ;;; (let ((var initial))
1192 ;;; (setq var (+ var step))
1194 (defun maybe-infer-iteration-var-type (var initial-type)
1195 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1197 (() (null (rest sets)) :exit-if-null)
1198 (set-use (principal-lvar-use (set-value set)))
1199 (() (and (combination-p set-use)
1200 (eq (combination-kind set-use) :known)
1201 (fun-info-p (combination-fun-info set-use))
1202 (not (node-to-be-deleted-p set-use))
1203 (eq (combination-fun-source-name set-use) '+))
1205 (+-args (basic-combination-args set-use))
1206 (() (and (proper-list-of-length-p +-args 2 2)
1207 (let ((first (principal-lvar-use
1210 (eq (ref-leaf first) var))))
1212 (step-type (lvar-type (second +-args)))
1213 (set-type (lvar-type (set-value set))))
1214 (when (and (numeric-type-p initial-type)
1215 (numeric-type-p step-type)
1216 (numeric-type-equal initial-type step-type))
1217 (multiple-value-bind (low high)
1218 (cond ((csubtypep step-type (specifier-type '(real 0 *)))
1219 (values (numeric-type-low initial-type)
1220 (when (and (numeric-type-p set-type)
1221 (numeric-type-equal set-type initial-type))
1222 (numeric-type-high set-type))))
1223 ((csubtypep step-type (specifier-type '(real * 0)))
1224 (values (when (and (numeric-type-p set-type)
1225 (numeric-type-equal set-type initial-type))
1226 (numeric-type-low set-type))
1227 (numeric-type-high initial-type)))
1230 (modified-numeric-type initial-type
1233 :enumerable nil)))))
1234 (deftransform + ((x y) * * :result result)
1235 "check for iteration variable reoptimization"
1236 (let ((dest (principal-lvar-end result))
1237 (use (principal-lvar-use x)))
1238 (when (and (ref-p use)
1242 (reoptimize-lvar (set-value dest))))
1243 (give-up-ir1-transform))
1245 ;;; Figure out the type of a LET variable that has sets. We compute
1246 ;;; the union of the INITIAL-TYPE and the types of all the set
1247 ;;; values and to a PROPAGATE-TO-REFS with this type.
1248 (defun propagate-from-sets (var initial-type)
1249 (collect ((res initial-type type-union))
1250 (dolist (set (basic-var-sets var))
1251 (let ((type (lvar-type (set-value set))))
1253 (when (node-reoptimize set)
1254 (derive-node-type set (make-single-value-type type))
1255 (setf (node-reoptimize set) nil))))
1257 (awhen (maybe-infer-iteration-var-type var initial-type)
1259 (propagate-to-refs var res)))
1262 ;;; If a LET variable, find the initial value's type and do
1263 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1265 (defun ir1-optimize-set (node)
1266 (declare (type cset node))
1267 (let ((var (set-var node)))
1268 (when (and (lambda-var-p var) (leaf-refs var))
1269 (let ((home (lambda-var-home var)))
1270 (when (eq (functional-kind home) :let)
1271 (let* ((initial-value (let-var-initial-value var))
1272 (initial-type (lvar-type initial-value)))
1273 (setf (lvar-reoptimize initial-value) nil)
1274 (propagate-from-sets var initial-type))))))
1276 (derive-node-type node (make-single-value-type
1277 (lvar-type (set-value node))))
1280 ;;; Return true if the value of REF will always be the same (and is
1281 ;;; thus legal to substitute.)
1282 (defun constant-reference-p (ref)
1283 (declare (type ref ref))
1284 (let ((leaf (ref-leaf ref)))
1286 ((or constant functional) t)
1288 (null (lambda-var-sets leaf)))
1290 (not (eq (defined-fun-inlinep leaf) :notinline)))
1292 (case (global-var-kind leaf)
1294 (let ((name (leaf-source-name leaf)))
1296 (eq (symbol-package (fun-name-block-name name))
1298 (info :function :info name)))))))))
1300 ;;; If we have a non-set LET var with a single use, then (if possible)
1301 ;;; replace the variable reference's LVAR with the arg lvar.
1303 ;;; We change the REF to be a reference to NIL with unused value, and
1304 ;;; let it be flushed as dead code. A side effect of this substitution
1305 ;;; is to delete the variable.
1306 (defun substitute-single-use-lvar (arg var)
1307 (declare (type lvar arg) (type lambda-var var))
1308 (binding* ((ref (first (leaf-refs var)))
1309 (lvar (node-lvar ref) :exit-if-null)
1310 (dest (lvar-dest lvar)))
1312 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1313 ;; LVAR-USEs should not be met on one path.
1314 (eq (lvar-uses lvar) ref)
1316 ;; we should not change lifetime of unknown values lvars
1318 (and (type-single-value-p (lvar-derived-type arg))
1319 (multiple-value-bind (pdest pprev)
1320 (principal-lvar-end lvar)
1321 (declare (ignore pdest))
1322 (lvar-single-value-p pprev))))
1324 (or (eq (basic-combination-fun dest) lvar)
1325 (and (eq (basic-combination-kind dest) :local)
1326 (type-single-value-p (lvar-derived-type arg)))))
1328 ;; While CRETURN and EXIT nodes may be known-values,
1329 ;; they have their own complications, such as
1330 ;; substitution into CRETURN may create new tail calls.
1333 (aver (lvar-single-value-p lvar))
1335 (eq (node-home-lambda ref)
1336 (lambda-home (lambda-var-home var))))
1337 (setf (node-derived-type ref) *wild-type*)
1338 (substitute-lvar-uses lvar arg)
1339 (delete-lvar-use ref)
1340 (change-ref-leaf ref (find-constant nil))
1343 (reoptimize-lvar lvar)
1346 ;;; Delete a LET, removing the call and bind nodes, and warning about
1347 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1348 ;;; along right away and delete the REF and then the lambda, since we
1349 ;;; flush the FUN lvar.
1350 (defun delete-let (clambda)
1351 (declare (type clambda clambda))
1352 (aver (functional-letlike-p clambda))
1353 (note-unreferenced-vars clambda)
1354 (let ((call (let-combination clambda)))
1355 (flush-dest (basic-combination-fun call))
1357 (unlink-node (lambda-bind clambda))
1358 (setf (lambda-bind clambda) nil))
1359 (setf (functional-kind clambda) :zombie)
1360 (let ((home (lambda-home clambda)))
1361 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1364 ;;; This function is called when one of the arguments to a LET
1365 ;;; changes. We look at each changed argument. If the corresponding
1366 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1367 ;;; consider substituting for the variable, and also propagate
1368 ;;; derived-type information for the arg to all the VAR's refs.
1370 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1371 ;;; subtype of the argument's leaf type. This prevents type checking
1372 ;;; from being defeated, and also ensures that the best representation
1373 ;;; for the variable can be used.
1375 ;;; Substitution of individual references is inhibited if the
1376 ;;; reference is in a different component from the home. This can only
1377 ;;; happen with closures over top level lambda vars. In such cases,
1378 ;;; the references may have already been compiled, and thus can't be
1379 ;;; retroactively modified.
1381 ;;; If all of the variables are deleted (have no references) when we
1382 ;;; are done, then we delete the LET.
1384 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1386 (defun propagate-let-args (call fun)
1387 (declare (type combination call) (type clambda fun))
1388 (loop for arg in (combination-args call)
1389 and var in (lambda-vars fun) do
1390 (when (and arg (lvar-reoptimize arg))
1391 (setf (lvar-reoptimize arg) nil)
1393 ((lambda-var-sets var)
1394 (propagate-from-sets var (lvar-type arg)))
1395 ((let ((use (lvar-uses arg)))
1397 (let ((leaf (ref-leaf use)))
1398 (when (and (constant-reference-p use)
1399 (csubtypep (leaf-type leaf)
1400 ;; (NODE-DERIVED-TYPE USE) would
1401 ;; be better -- APD, 2003-05-15
1403 (propagate-to-refs var (lvar-type arg))
1404 (let ((use-component (node-component use)))
1405 (prog1 (substitute-leaf-if
1407 (cond ((eq (node-component ref) use-component)
1410 (aver (lambda-toplevelish-p (lambda-home fun)))
1414 ((and (null (rest (leaf-refs var)))
1415 (substitute-single-use-lvar arg var)))
1417 (propagate-to-refs var (lvar-type arg))))))
1419 (when (every #'not (combination-args call))
1424 ;;; This function is called when one of the args to a non-LET local
1425 ;;; call changes. For each changed argument corresponding to an unset
1426 ;;; variable, we compute the union of the types across all calls and
1427 ;;; propagate this type information to the var's refs.
1429 ;;; If the function has an XEP, then we don't do anything, since we
1430 ;;; won't discover anything.
1432 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1433 ;;; corresponding to changed arguments in CALL, since the only use in
1434 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1436 (defun propagate-local-call-args (call fun)
1437 (declare (type combination call) (type clambda fun))
1439 (unless (or (functional-entry-fun fun)
1440 (lambda-optional-dispatch fun))
1441 (let* ((vars (lambda-vars fun))
1442 (union (mapcar (lambda (arg var)
1444 (lvar-reoptimize arg)
1445 (null (basic-var-sets var)))
1447 (basic-combination-args call)
1449 (this-ref (lvar-use (basic-combination-fun call))))
1451 (dolist (arg (basic-combination-args call))
1453 (setf (lvar-reoptimize arg) nil)))
1455 (dolist (ref (leaf-refs fun))
1456 (let ((dest (node-dest ref)))
1457 (unless (or (eq ref this-ref) (not dest))
1459 (mapcar (lambda (this-arg old)
1461 (setf (lvar-reoptimize this-arg) nil)
1462 (type-union (lvar-type this-arg) old)))
1463 (basic-combination-args dest)
1466 (loop for var in vars
1468 when type do (propagate-to-refs var type))))
1472 ;;;; multiple values optimization
1474 ;;; Do stuff to notice a change to a MV combination node. There are
1475 ;;; two main branches here:
1476 ;;; -- If the call is local, then it is already a MV let, or should
1477 ;;; become one. Note that although all :LOCAL MV calls must eventually
1478 ;;; be converted to :MV-LETs, there can be a window when the call
1479 ;;; is local, but has not been LET converted yet. This is because
1480 ;;; the entry-point lambdas may have stray references (in other
1481 ;;; entry points) that have not been deleted yet.
1482 ;;; -- The call is full. This case is somewhat similar to the non-MV
1483 ;;; combination optimization: we propagate return type information and
1484 ;;; notice non-returning calls. We also have an optimization
1485 ;;; which tries to convert MV-CALLs into MV-binds.
1486 (defun ir1-optimize-mv-combination (node)
1487 (ecase (basic-combination-kind node)
1489 (let ((fun-lvar (basic-combination-fun node)))
1490 (when (lvar-reoptimize fun-lvar)
1491 (setf (lvar-reoptimize fun-lvar) nil)
1492 (maybe-let-convert (combination-lambda node))))
1493 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1494 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1495 (unless (convert-mv-bind-to-let node)
1496 (ir1-optimize-mv-bind node))))
1498 (let* ((fun (basic-combination-fun node))
1499 (fun-changed (lvar-reoptimize fun))
1500 (args (basic-combination-args node)))
1502 (setf (lvar-reoptimize fun) nil)
1503 (let ((type (lvar-type fun)))
1504 (when (fun-type-p type)
1505 (derive-node-type node (fun-type-returns type))))
1506 (maybe-terminate-block node nil)
1507 (let ((use (lvar-uses fun)))
1508 (when (and (ref-p use) (functional-p (ref-leaf use)))
1509 (convert-call-if-possible use node)
1510 (when (eq (basic-combination-kind node) :local)
1511 (maybe-let-convert (ref-leaf use))))))
1512 (unless (or (eq (basic-combination-kind node) :local)
1513 (eq (lvar-fun-name fun) '%throw))
1514 (ir1-optimize-mv-call node))
1516 (setf (lvar-reoptimize arg) nil))))
1520 ;;; Propagate derived type info from the values lvar to the vars.
1521 (defun ir1-optimize-mv-bind (node)
1522 (declare (type mv-combination node))
1523 (let* ((arg (first (basic-combination-args node)))
1524 (vars (lambda-vars (combination-lambda node)))
1525 (n-vars (length vars))
1526 (types (values-type-in (lvar-derived-type arg)
1528 (loop for var in vars
1530 do (if (basic-var-sets var)
1531 (propagate-from-sets var type)
1532 (propagate-to-refs var type)))
1533 (setf (lvar-reoptimize arg) nil))
1536 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1538 ;;; -- The call has only one argument, and
1539 ;;; -- The function has a known fixed number of arguments, or
1540 ;;; -- The argument yields a known fixed number of values.
1542 ;;; What we do is change the function in the MV-CALL to be a lambda
1543 ;;; that "looks like an MV bind", which allows
1544 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1545 ;;; converted (the next time around.) This new lambda just calls the
1546 ;;; actual function with the MV-BIND variables as arguments. Note that
1547 ;;; this new MV bind is not let-converted immediately, as there are
1548 ;;; going to be stray references from the entry-point functions until
1549 ;;; they get deleted.
1551 ;;; In order to avoid loss of argument count checking, we only do the
1552 ;;; transformation according to a known number of expected argument if
1553 ;;; safety is unimportant. We can always convert if we know the number
1554 ;;; of actual values, since the normal call that we build will still
1555 ;;; do any appropriate argument count checking.
1557 ;;; We only attempt the transformation if the called function is a
1558 ;;; constant reference. This allows us to just splice the leaf into
1559 ;;; the new function, instead of trying to somehow bind the function
1560 ;;; expression. The leaf must be constant because we are evaluating it
1561 ;;; again in a different place. This also has the effect of squelching
1562 ;;; multiple warnings when there is an argument count error.
1563 (defun ir1-optimize-mv-call (node)
1564 (let ((fun (basic-combination-fun node))
1565 (*compiler-error-context* node)
1566 (ref (lvar-uses (basic-combination-fun node)))
1567 (args (basic-combination-args node)))
1569 (unless (and (ref-p ref) (constant-reference-p ref)
1571 (return-from ir1-optimize-mv-call))
1573 (multiple-value-bind (min max)
1574 (fun-type-nargs (lvar-type fun))
1576 (multiple-value-bind (types nvals)
1577 (values-types (lvar-derived-type (first args)))
1578 (declare (ignore types))
1579 (if (eq nvals :unknown) nil nvals))))
1582 (when (and min (< total-nvals min))
1584 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1587 (setf (basic-combination-kind node) :error)
1588 (return-from ir1-optimize-mv-call))
1589 (when (and max (> total-nvals max))
1591 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1594 (setf (basic-combination-kind node) :error)
1595 (return-from ir1-optimize-mv-call)))
1597 (let ((count (cond (total-nvals)
1598 ((and (policy node (zerop verify-arg-count))
1603 (with-ir1-environment-from-node node
1604 (let* ((dums (make-gensym-list count))
1606 (fun (ir1-convert-lambda
1607 `(lambda (&optional ,@dums &rest ,ignore)
1608 (declare (ignore ,ignore))
1609 (funcall ,(ref-leaf ref) ,@dums)))))
1610 (change-ref-leaf ref fun)
1611 (aver (eq (basic-combination-kind node) :full))
1612 (locall-analyze-component *current-component*)
1613 (aver (eq (basic-combination-kind node) :local)))))))))
1617 ;;; (multiple-value-bind
1626 ;;; What we actually do is convert the VALUES combination into a
1627 ;;; normal LET combination calling the original :MV-LET lambda. If
1628 ;;; there are extra args to VALUES, discard the corresponding
1629 ;;; lvars. If there are insufficient args, insert references to NIL.
1630 (defun convert-mv-bind-to-let (call)
1631 (declare (type mv-combination call))
1632 (let* ((arg (first (basic-combination-args call)))
1633 (use (lvar-uses arg)))
1634 (when (and (combination-p use)
1635 (eq (lvar-fun-name (combination-fun use))
1637 (let* ((fun (combination-lambda call))
1638 (vars (lambda-vars fun))
1639 (vals (combination-args use))
1640 (nvars (length vars))
1641 (nvals (length vals)))
1642 (cond ((> nvals nvars)
1643 (mapc #'flush-dest (subseq vals nvars))
1644 (setq vals (subseq vals 0 nvars)))
1646 (with-ir1-environment-from-node use
1647 (let ((node-prev (node-prev use)))
1648 (setf (node-prev use) nil)
1649 (setf (ctran-next node-prev) nil)
1650 (collect ((res vals))
1651 (loop for count below (- nvars nvals)
1652 for prev = node-prev then ctran
1653 for ctran = (make-ctran)
1654 and lvar = (make-lvar use)
1655 do (reference-constant prev ctran lvar nil)
1657 finally (link-node-to-previous-ctran
1659 (setq vals (res)))))))
1660 (setf (combination-args use) vals)
1661 (flush-dest (combination-fun use))
1662 (let ((fun-lvar (basic-combination-fun call)))
1663 (setf (lvar-dest fun-lvar) use)
1664 (setf (combination-fun use) fun-lvar)
1665 (flush-lvar-externally-checkable-type fun-lvar))
1666 (setf (combination-kind use) :local)
1667 (setf (functional-kind fun) :let)
1668 (flush-dest (first (basic-combination-args call)))
1671 (reoptimize-lvar (first vals)))
1672 (propagate-to-args use fun)
1673 (reoptimize-call use))
1677 ;;; (values-list (list x y z))
1682 ;;; In implementation, this is somewhat similar to
1683 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1684 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1685 ;;; (allowing the LIST to be flushed.)
1687 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1688 (defoptimizer (values-list optimizer) ((list) node)
1689 (let ((use (lvar-uses list)))
1690 (when (and (combination-p use)
1691 (eq (lvar-fun-name (combination-fun use))
1694 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1695 (change-ref-leaf (lvar-uses (combination-fun node))
1696 (find-free-fun 'values "in a strange place"))
1697 (setf (combination-kind node) :full)
1698 (let ((args (combination-args use)))
1700 (setf (lvar-dest arg) node)
1701 (flush-lvar-externally-checkable-type arg))
1702 (setf (combination-args use) nil)
1704 (setf (combination-args node) args))
1707 ;;; If VALUES appears in a non-MV context, then effectively convert it
1708 ;;; to a PROG1. This allows the computation of the additional values
1709 ;;; to become dead code.
1710 (deftransform values ((&rest vals) * * :node node)
1711 (unless (lvar-single-value-p (node-lvar node))
1712 (give-up-ir1-transform))
1713 (setf (node-derived-type node)
1714 (make-short-values-type (list (single-value-type
1715 (node-derived-type node)))))
1716 (principal-lvar-single-valuify (node-lvar node))
1718 (let ((dummies (make-gensym-list (length (cdr vals)))))
1719 `(lambda (val ,@dummies)
1720 (declare (ignore ,@dummies))
1726 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1727 (declare (type cast cast))
1728 (let ((value (cast-value cast))
1729 (atype (cast-asserted-type cast)))
1730 (when (not do-not-optimize)
1731 (let ((lvar (node-lvar cast)))
1732 (when (values-subtypep (lvar-derived-type value)
1733 (cast-asserted-type cast))
1734 (delete-filter cast lvar value)
1736 (reoptimize-lvar lvar)
1737 (when (lvar-single-value-p lvar)
1738 (note-single-valuified-lvar lvar)))
1739 (return-from ir1-optimize-cast t))
1741 (when (and (listp (lvar-uses value))
1743 ;; Pathwise removing of CAST
1744 (let ((ctran (node-next cast))
1745 (dest (lvar-dest lvar))
1748 (do-uses (use value)
1749 (when (and (values-subtypep (node-derived-type use) atype)
1750 (immediately-used-p value use))
1752 (when ctran (ensure-block-start ctran))
1753 (setq next-block (first (block-succ (node-block cast))))
1754 (ensure-block-start (node-prev cast))
1755 (reoptimize-lvar lvar)
1756 (setf (lvar-%derived-type value) nil))
1757 (%delete-lvar-use use)
1758 (add-lvar-use use lvar)
1759 (unlink-blocks (node-block use) (node-block cast))
1760 (link-blocks (node-block use) next-block)
1761 (when (and (return-p dest)
1762 (basic-combination-p use)
1763 (eq (basic-combination-kind use) :local))
1765 (dolist (use (merges))
1766 (merge-tail-sets use)))))))
1768 (let* ((value-type (lvar-derived-type value))
1769 (int (values-type-intersection value-type atype)))
1770 (derive-node-type cast int)
1771 (when (eq int *empty-type*)
1772 (unless (eq value-type *empty-type*)
1774 ;; FIXME: Do it in one step.
1777 (if (cast-single-value-p cast)
1779 `(multiple-value-call #'list 'dummy)))
1782 ;; FIXME: Derived type.
1783 `(%compile-time-type-error 'dummy
1784 ',(type-specifier atype)
1785 ',(type-specifier value-type)))
1786 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1787 ;; functions, so we declare the return type of
1788 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1790 (setq value (cast-value cast))
1791 (derive-node-type (lvar-uses value) *empty-type*)
1792 (maybe-terminate-block (lvar-uses value) nil)
1793 ;; FIXME: Is it necessary?
1794 (aver (null (block-pred (node-block cast))))
1795 (delete-block-lazily (node-block cast))
1796 (return-from ir1-optimize-cast)))
1797 (when (eq (node-derived-type cast) *empty-type*)
1798 (maybe-terminate-block cast nil))
1800 (when (and (cast-%type-check cast)
1801 (values-subtypep value-type
1802 (cast-type-to-check cast)))
1803 (setf (cast-%type-check cast) nil))))
1805 (unless do-not-optimize
1806 (setf (node-reoptimize cast) nil)))