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Revision 1.77 - (hide annotations)
Tue Apr 29 11:58:16 2003 UTC (10 years, 11 months ago) by gerd
Branch: MAIN
CVS Tags: snapshot-2003-10, dynamic-extent-base, sparc_gencgc_merge, sparc_gencgc, lisp-executable-base
Branch point for: sparc_gencgc_branch, dynamic-extent, lisp-executable
Changes since 1.76: +45 -58 lines
	Fix for various ANSI test cases that fail when compiled because
	argument type checks are constant-folded away.

	* src/compiler/ir1opt.lisp (constant-fold-call): In safe code,
	don't constant-fold a call if one of its arguments requires
	a type check.

	* src/compiler/checkgen.lisp (probable-type-check-p): Return
	true for :error type-checks if safety = 3.

	Fix ENDP.* test failures when running tests compiled.  From SBCL,
	basically.

	* src/compiler/ir1opt.lisp (ir1-optimize, ir1-optimize-if):
	Don't eliminate if-tests requiring type checks.

	* src/compiler/checkgen.lisp (continuation-check-types):
	Add parameter force-hairy.
	(generate-type-checks): Call continuation-check-types with
	force-hairy true for :error continuations in safe code.
1 wlott 1.1 ;;; -*- Package: C; Log: C.Log -*-
2     ;;;
3     ;;; **********************************************************************
4 ram 1.24 ;;; This code was written as part of the CMU Common Lisp project at
5     ;;; Carnegie Mellon University, and has been placed in the public domain.
6     ;;;
7     (ext:file-comment
8 gerd 1.77 "$Header: /tiger/var/lib/cvsroots/cmucl/src/compiler/ir1opt.lisp,v 1.77 2003/04/29 11:58:16 gerd Exp $")
9 ram 1.24 ;;;
10 wlott 1.1 ;;; **********************************************************************
11     ;;;
12     ;;; This file implements the IR1 optimization phase of the compiler. IR1
13     ;;; optimization is a grab-bag of optimizations that don't make major changes
14     ;;; to the block-level control flow and don't use flow analysis. These
15     ;;; optimizations can mostly be classified as "meta-evaluation", but there is a
16     ;;; sizable top-down component as well.
17     ;;;
18     ;;; Written by Rob MacLachlan
19     ;;;
20 ram 1.46 (in-package :c)
21 wlott 1.1
22    
23     ;;;; Interface for obtaining results of constant folding:
24    
25     ;;; Constant-Continuation-P -- Interface
26     ;;;
27     ;;; Return true if the sole use of Cont is a reference to a constant leaf.
28     ;;;
29     (defun constant-continuation-p (cont)
30 dtc 1.71 (declare (type continuation cont) (values boolean))
31 wlott 1.1 (let ((use (continuation-use cont)))
32     (and (ref-p use)
33     (constant-p (ref-leaf use)))))
34    
35    
36     ;;; Continuation-Value -- Interface
37     ;;;
38     ;;; Return the constant value for a continuation whose only use is a
39     ;;; constant node.
40     ;;;
41     (defun continuation-value (cont)
42 dtc 1.71 (declare (type continuation cont))
43 ram 1.10 (assert (constant-continuation-p cont))
44 wlott 1.1 (constant-value (ref-leaf (continuation-use cont))))
45    
46    
47     ;;;; Interface for obtaining results of type inference:
48    
49     ;;; CONTINUATION-PROVEN-TYPE -- Interface
50     ;;;
51     ;;; Return a (possibly values) type that describes what we have proven about
52     ;;; the type of Cont without taking any type assertions into consideration.
53     ;;; This is just the union of the NODE-DERIVED-TYPE of all the uses. Most
54     ;;; often people use CONTINUATION-DERIVED-TYPE or CONTINUATION-TYPE instead of
55     ;;; using this function directly.
56     ;;;
57     (defun continuation-proven-type (cont)
58     (declare (type continuation cont))
59     (ecase (continuation-kind cont)
60     ((:block-start :deleted-block-start)
61     (let ((uses (block-start-uses (continuation-block cont))))
62     (if uses
63     (do ((res (node-derived-type (first uses))
64     (values-type-union (node-derived-type (first current))
65     res))
66     (current (rest uses) (rest current)))
67     ((null current) res))
68     *empty-type*)))
69     (:inside-block
70     (node-derived-type (continuation-use cont)))))
71    
72    
73     ;;; Continuation-Derived-Type -- Interface
74     ;;;
75     ;;; Our best guess for the type of this continuation's value. Note that
76     ;;; this may be Values or Function type, which cannot be passed as an argument
77     ;;; to the normal type operations. See Continuation-Type. This may be called
78     ;;; on deleted continuations, always returning *.
79     ;;;
80     ;;; What we do is call CONTINUATION-PROVEN-TYPE and check whether the result
81     ;;; is a subtype of the assertion. If so, return the proven type and set
82     ;;; TYPE-CHECK to nil. Otherwise, return the intersection of the asserted and
83     ;;; proven types, and set TYPE-CHECK T. If TYPE-CHECK already has a non-null
84     ;;; value, then preserve it. Only in the somewhat unusual circumstance of
85     ;;; a newly discovered assertion will we change TYPE-CHECK from NIL to T.
86     ;;;
87     ;;; The result value is cached in the Continuation-%Derived-Type. If the
88     ;;; slot is true, just return that value, otherwise recompute and stash the
89     ;;; value there.
90     ;;;
91 pw 1.74 (declaim (inline continuation-derived-type))
92 wlott 1.1 (defun continuation-derived-type (cont)
93     (declare (type continuation cont))
94     (or (continuation-%derived-type cont)
95     (%continuation-derived-type cont)))
96     ;;;
97     (defun %continuation-derived-type (cont)
98     (declare (type continuation cont))
99     (let ((proven (continuation-proven-type cont))
100     (asserted (continuation-asserted-type cont)))
101     (cond ((values-subtypep proven asserted)
102     (setf (continuation-%type-check cont) nil)
103     (setf (continuation-%derived-type cont) proven))
104     (t
105     (unless (or (continuation-%type-check cont)
106     (not (continuation-dest cont))
107     (eq asserted *universal-type*))
108     (setf (continuation-%type-check cont) t))
109    
110     (setf (continuation-%derived-type cont)
111     (values-type-intersection asserted proven))))))
112    
113    
114     ;;; CONTINUATION-TYPE-CHECK -- Interface
115     ;;;
116     ;;; Call CONTINUATION-DERIVED-TYPE to make sure the slot is up to date, then
117     ;;; return it.
118     ;;;
119 pw 1.74 (declaim (inline continuation-type-check))
120 wlott 1.1 (defun continuation-type-check (cont)
121     (declare (type continuation cont))
122     (continuation-derived-type cont)
123     (continuation-%type-check cont))
124    
125    
126     ;;; Continuation-Type -- Interface
127     ;;;
128     ;;; Return the derived type for Cont's first value. This is guaranteed not
129     ;;; to be a Values or Function type.
130     ;;;
131     (defun continuation-type (cont)
132 dtc 1.71 (declare (type continuation cont) (values ctype))
133 wlott 1.1 (single-value-type (continuation-derived-type cont)))
134    
135    
136     ;;;; Interface routines used by optimizers:
137    
138     ;;; Reoptimize-Continuation -- Interface
139     ;;;
140     ;;; This function is called by optimizers to indicate that something
141     ;;; interesting has happened to the value of Cont. Optimizers must make sure
142     ;;; that they don't call for reoptimization when nothing has happened, since
143     ;;; optimization will fail to terminate.
144     ;;;
145     ;;; We clear any cached type for the continuation and set the reoptimize
146     ;;; flags on everything in sight, unless the continuation is deleted (in which
147     ;;; case we do nothing.)
148     ;;;
149     ;;; Since this can get called curing IR1 conversion, we have to be careful
150     ;;; not to fly into space when the Dest's Prev is missing.
151     ;;;
152     (defun reoptimize-continuation (cont)
153     (declare (type continuation cont))
154 ram 1.29 (unless (member (continuation-kind cont) '(:deleted :unused))
155 wlott 1.1 (setf (continuation-%derived-type cont) nil)
156     (let ((dest (continuation-dest cont)))
157     (when dest
158     (setf (continuation-reoptimize cont) t)
159     (setf (node-reoptimize dest) t)
160     (let ((prev (node-prev dest)))
161     (when prev
162     (let* ((block (continuation-block prev))
163     (component (block-component block)))
164 ram 1.18 (when (typep dest 'cif)
165     (setf (block-test-modified block) t))
166 wlott 1.1 (setf (block-reoptimize block) t)
167     (setf (component-reoptimize component) t))))))
168     (do-uses (node cont)
169     (setf (block-type-check (node-block node)) t)))
170     (undefined-value))
171    
172    
173     ;;; Derive-Node-Type -- Interface
174     ;;;
175     ;;; Annotate Node to indicate that its result has been proven to be typep to
176     ;;; RType. After IR1 conversion has happened, this is the only correct way to
177     ;;; supply information discovered about a node's type. If you fuck with the
178     ;;; Node-Derived-Type directly, then information may be lost and reoptimization
179     ;;; may not happen.
180     ;;;
181     ;;; What we do is intersect Rtype with Node's Derived-Type. If the
182     ;;; intersection is different from the old type, then we do a
183     ;;; Reoptimize-Continuation on the Node-Cont.
184     ;;;
185     (defun derive-node-type (node rtype)
186     (declare (type node node) (type ctype rtype))
187     (let ((node-type (node-derived-type node)))
188     (unless (eq node-type rtype)
189     (let ((int (values-type-intersection node-type rtype)))
190     (when (type/= node-type int)
191 ram 1.38 (when (and *check-consistency*
192     (eq int *empty-type*)
193 ram 1.34 (not (eq rtype *empty-type*)))
194     (let ((*compiler-error-context* node))
195     (compiler-warning
196     "New inferred type ~S conflicts with old type:~
197     ~% ~S~%*** Bug?"
198     (type-specifier rtype) (type-specifier node-type))))
199 wlott 1.1 (setf (node-derived-type node) int)
200     (reoptimize-continuation (node-cont node))))))
201     (undefined-value))
202    
203 dtc 1.70 (declaim (start-block assert-continuation-type
204     assert-continuation-optional-type assert-call-type))
205 wlott 1.1
206     ;;; Assert-Continuation-Type -- Interface
207     ;;;
208     ;;; Similar to Derive-Node-Type, but asserts that it is an error for Cont's
209     ;;; value not to be typep to Type. If we improve the assertion, we set
210 ram 1.11 ;;; TYPE-CHECK and TYPE-ASSERTED to guarantee that the new assertion will be
211     ;;; checked.
212 wlott 1.1 ;;;
213     (defun assert-continuation-type (cont type)
214     (declare (type continuation cont) (type ctype type))
215     (let ((cont-type (continuation-asserted-type cont)))
216     (unless (eq cont-type type)
217     (let ((int (values-type-intersection cont-type type)))
218     (when (type/= cont-type int)
219     (setf (continuation-asserted-type cont) int)
220     (do-uses (node cont)
221 ram 1.11 (setf (block-attributep (block-flags (node-block node))
222     type-check type-asserted)
223     t))
224 wlott 1.1 (reoptimize-continuation cont)))))
225     (undefined-value))
226    
227    
228 dtc 1.70 ;;; Assert-continuation-optional-type -- Interface
229     ;;;
230     ;;; Similar to Assert-Continuation-Type, but asserts that the type is
231     ;;; for an optional argument and that other arguments may be received.
232     ;;;
233     (defun assert-continuation-optional-type (cont type)
234     (declare (type continuation cont) (type ctype type))
235     (let ((opt-type (make-values-type :optional (list type)
236     :rest *universal-type*)))
237     (assert-continuation-type cont opt-type)))
238    
239    
240 wlott 1.1 ;;; Assert-Call-Type -- Interface
241     ;;;
242     ;;; Assert that Call is to a function of the specified Type. It is assumed
243     ;;; that the call is legal and has only constants in the keyword positions.
244     ;;;
245     (defun assert-call-type (call type)
246     (declare (type combination call) (type function-type type))
247     (derive-node-type call (function-type-returns type))
248     (let ((args (combination-args call)))
249     (dolist (req (function-type-required type))
250     (when (null args) (return-from assert-call-type))
251     (let ((arg (pop args)))
252 dtc 1.70 (assert-continuation-optional-type arg req)))
253 wlott 1.1 (dolist (opt (function-type-optional type))
254     (when (null args) (return-from assert-call-type))
255     (let ((arg (pop args)))
256 dtc 1.70 (assert-continuation-optional-type arg opt)))
257 wlott 1.1
258     (let ((rest (function-type-rest type)))
259     (when rest
260     (dolist (arg args)
261 dtc 1.70 (assert-continuation-optional-type arg rest))))
262 wlott 1.1
263     (dolist (key (function-type-keywords type))
264     (let ((name (key-info-name key)))
265     (do ((arg args (cddr arg)))
266     ((null arg))
267     (when (eq (continuation-value (first arg)) name)
268 dtc 1.70 (assert-continuation-optional-type
269 wlott 1.1 (second arg) (key-info-type key)))))))
270     (undefined-value))
271    
272    
273 ram 1.50 ;;;; IR1-OPTIMIZE:
274    
275     (declaim (start-block ir1-optimize))
276    
277 wlott 1.1 ;;; IR1-Optimize -- Interface
278     ;;;
279     ;;; Do one forward pass over Component, deleting unreachable blocks and
280 ram 1.11 ;;; doing IR1 optimizations. We can ignore all blocks that don't have the
281     ;;; Reoptimize flag set. If Component-Reoptimize is true when we are done,
282 wlott 1.1 ;;; then another iteration would be beneficial.
283     ;;;
284     ;;; We delete blocks when there is either no predecessor or the block is in
285     ;;; a lambda that has been deleted. These blocks would eventually be deleted
286     ;;; by DFO recomputation, but doing it here immediately makes the effect
287     ;;; avaliable to IR1 optimization.
288     ;;;
289     (defun ir1-optimize (component)
290     (declare (type component component))
291     (setf (component-reoptimize component) nil)
292     (do-blocks (block component)
293     (cond
294     ((or (block-delete-p block)
295     (null (block-pred block))
296 ram 1.11 (eq (functional-kind (block-home-lambda block)) :deleted))
297 wlott 1.1 (delete-block block))
298     (t
299     (loop
300     (let ((succ (block-succ block)))
301     (unless (and succ (null (rest succ)))
302     (return)))
303    
304     (let ((last (block-last block)))
305     (typecase last
306     (cif
307 gerd 1.77 ;;
308     ;; Don't flush an if-test if it requires a type check.
309     (cond ((memq (continuation-type-check (if-test last))
310     '(nil :deleted))
311     (flush-dest (if-test last))
312     (when (unlink-node last) (return)))
313     (t
314     (return))))
315 wlott 1.1 (exit
316     (when (maybe-delete-exit last) (return)))))
317    
318     (unless (join-successor-if-possible block)
319     (return)))
320    
321 ram 1.11 (when (and (block-reoptimize block) (block-component block))
322 wlott 1.1 (assert (not (block-delete-p block)))
323     (ir1-optimize-block block))
324    
325 ram 1.11 (when (and (block-flush-p block) (block-component block))
326 wlott 1.1 (assert (not (block-delete-p block)))
327     (flush-dead-code block)))))
328    
329     (undefined-value))
330    
331    
332     ;;; IR1-Optimize-Block -- Internal
333     ;;;
334     ;;; Loop over the nodes in Block, looking for stuff that needs to be
335     ;;; optimized. We dispatch off of the type of each node with its reoptimize
336     ;;; flag set:
337     ;;; -- With a combination, we call Propagate-Function-Change whenever the
338     ;;; function changes, and call IR1-Optimize-Combination if any argument
339     ;;; changes.
340     ;;; -- With an Exit, we derive the node's type from the Value's type. We don't
341     ;;; propagate Cont's assertion to the Value, since if we did, this would
342     ;;; move the checking of Cont's assertion to the exit. This wouldn't work
343     ;;; with Catch and UWP, where the Exit node is just a placeholder for the
344     ;;; actual unknown exit.
345     ;;;
346     ;;; Note that we clear the node & block reoptimize flags *before* doing the
347     ;;; optimization. This ensures that the node or block will be reoptimized if
348 ram 1.19 ;;; necessary. We leave the NODE-OPTIMIZE flag set going into
349 wlott 1.1 ;;; IR1-OPTIMIZE-RETURN, since it wants to clear the flag itself.
350     ;;;
351     (defun ir1-optimize-block (block)
352     (declare (type cblock block))
353     (setf (block-reoptimize block) nil)
354 ram 1.19 (do-nodes (node cont block :restart-p t)
355 wlott 1.1 (when (node-reoptimize node)
356     (setf (node-reoptimize node) nil)
357     (typecase node
358     (ref)
359     (combination
360 ram 1.50 (ir1-optimize-combination node))
361 wlott 1.1 (cif
362     (ir1-optimize-if node))
363     (creturn
364     (setf (node-reoptimize node) t)
365     (ir1-optimize-return node))
366 ram 1.6 (mv-combination
367 ram 1.21 (ir1-optimize-mv-combination node))
368 wlott 1.1 (exit
369     (let ((value (exit-value node)))
370     (when value
371     (derive-node-type node (continuation-derived-type value)))))
372     (cset
373     (ir1-optimize-set node)))))
374     (undefined-value))
375    
376 ram 1.50
377 wlott 1.1 ;;; Join-Successor-If-Possible -- Internal
378     ;;;
379     ;;; We cannot combine with a successor block if:
380     ;;; 1] The successor has more than one predecessor.
381     ;;; 2] The last node's Cont is also used somewhere else.
382     ;;; 3] The successor is the current block (infinite loop).
383     ;;; 4] The next block has a different cleanup, and thus we may want to insert
384     ;;; cleanup code between the two blocks at some point.
385     ;;; 5] The next block has a different home lambda, and thus the control
386     ;;; transfer is a non-local exit.
387     ;;;
388     ;;; If we succeed, we return true, otherwise false.
389     ;;;
390     ;;; Joining is easy when the successor's Start continuation is the same from
391     ;;; our Last's Cont. If they differ, then we can still join when the last
392     ;;; continuation has no next and the next continuation has no uses. In this
393 ram 1.5 ;;; case, we replace the next continuation with the last before joining the
394 wlott 1.1 ;;; blocks.
395     ;;;
396     (defun join-successor-if-possible (block)
397     (declare (type cblock block))
398     (let ((next (first (block-succ block))))
399 ram 1.11 (when (block-start next)
400 wlott 1.1 (let* ((last (block-last block))
401     (last-cont (node-cont last))
402 ram 1.11 (next-cont (block-start next)))
403 wlott 1.1 (cond ((or (rest (block-pred next))
404 ram 1.5 (not (eq (continuation-use last-cont) last))
405 wlott 1.1 (eq next block)
406 ram 1.11 (not (eq (block-end-cleanup block)
407     (block-start-cleanup next)))
408     (not (eq (block-home-lambda block)
409     (block-home-lambda next))))
410 wlott 1.1 nil)
411 ram 1.5 ((eq last-cont next-cont)
412 wlott 1.1 (join-blocks block next)
413     t)
414 ram 1.5 ((and (null (block-start-uses next))
415     (eq (continuation-kind last-cont) :inside-block))
416     (let ((next-node (continuation-next next-cont)))
417 ram 1.30 ;;
418     ;; If next-cont does have a dest, it must be unreachable,
419     ;; since there are no uses. DELETE-CONTINUATION will mark the
420     ;; dest block as delete-p [and also this block, unless it is
421     ;; no longer backward reachable from the dest block.]
422 ram 1.5 (delete-continuation next-cont)
423     (setf (node-prev next-node) last-cont)
424     (setf (continuation-next last-cont) next-node)
425     (setf (block-start next) last-cont)
426     (join-blocks block next))
427 wlott 1.1 t)
428     (t
429     nil))))))
430    
431    
432     ;;; Join-Blocks -- Internal
433     ;;;
434     ;;; Join together two blocks which have the same ending/starting
435     ;;; continuation. The code in Block2 is moved into Block1 and Block2 is
436 ram 1.11 ;;; deleted from the DFO. We combine the optimize flags for the two blocks so
437     ;;; that any indicated optimization gets done.
438 wlott 1.1 ;;;
439     (defun join-blocks (block1 block2)
440     (declare (type cblock block1 block2))
441     (let* ((last (block-last block2))
442     (last-cont (node-cont last))
443     (succ (block-succ block2))
444     (start2 (block-start block2)))
445     (do ((cont start2 (node-cont (continuation-next cont))))
446     ((eq cont last-cont)
447     (when (eq (continuation-kind last-cont) :inside-block)
448     (setf (continuation-block last-cont) block1)))
449     (setf (continuation-block cont) block1))
450    
451     (unlink-blocks block1 block2)
452     (dolist (block succ)
453     (unlink-blocks block2 block)
454     (link-blocks block1 block))
455    
456     (setf (block-last block1) last)
457     (setf (continuation-kind start2) :inside-block))
458    
459 ram 1.11 (setf (block-flags block1)
460     (attributes-union (block-flags block1)
461     (block-flags block2)
462     (block-attributes type-asserted test-modified)))
463 wlott 1.1
464     (let ((next (block-next block2))
465     (prev (block-prev block2)))
466     (setf (block-next prev) next)
467     (setf (block-prev next) prev))
468    
469     (undefined-value))
470    
471 ram 1.50 ;;; Flush-Dead-Code -- Internal
472     ;;;
473     ;;; Delete any nodes in Block whose value is unused and have no
474     ;;; side-effects. We can delete sets of lexical variables when the set
475     ;;; variable has no references.
476     ;;;
477     ;;; [### For now, don't delete potentially flushable calls when they have the
478     ;;; Call attribute. Someday we should look at the funcitonal args to determine
479     ;;; if they have any side-effects.]
480     ;;;
481     (defun flush-dead-code (block)
482     (declare (type cblock block))
483     (do-nodes-backwards (node cont block)
484     (unless (continuation-dest cont)
485     (typecase node
486     (ref
487     (delete-ref node)
488     (unlink-node node))
489     (combination
490     (let ((info (combination-kind node)))
491     (when (function-info-p info)
492     (let ((attr (function-info-attributes info)))
493     (when (and (ir1-attributep attr flushable)
494     (not (ir1-attributep attr call)))
495 gerd 1.76 (if (policy node (= safety 3))
496     ;; Don't flush calls to flushable functions if
497     ;; their value is unused in safe code, because
498     ;; this means something like (PROGN (FBOUNDP 42)
499     ;; T) won't signal an error. KLUDGE: The right
500     ;; thing to do here is probably teaching
501     ;; MAYBE-NEGATE-CHECK and friends to accept nil
502     ;; continuation-dests instead of faking one.
503     ;; Can't be bothered at present.
504     ;; Gerd, 2003-04-26.
505     (setf (continuation-dest cont)
506     (continuation-next cont))
507     (progn
508     (flush-dest (combination-fun node))
509     (dolist (arg (combination-args node))
510     (flush-dest arg))
511     (unlink-node node))))))))
512 ram 1.50 (mv-combination
513     (when (eq (basic-combination-kind node) :local)
514     (let ((fun (combination-lambda node)))
515     (when (dolist (var (lambda-vars fun) t)
516     (when (or (leaf-refs var)
517     (lambda-var-sets var))
518     (return nil)))
519     (flush-dest (first (basic-combination-args node)))
520     (delete-let fun)))))
521     (exit
522     (let ((value (exit-value node)))
523     (when value
524     (flush-dest value)
525     (setf (exit-value node) nil))))
526     (cset
527     (let ((var (set-var node)))
528     (when (and (lambda-var-p var)
529     (null (leaf-refs var)))
530     (flush-dest (set-value node))
531     (setf (basic-var-sets var)
532     (delete node (basic-var-sets var)))
533     (unlink-node node)))))))
534    
535     (setf (block-flush-p block) nil)
536     (undefined-value))
537    
538     (declaim (end-block))
539    
540 wlott 1.1
541     ;;;; Local call return type propagation:
542    
543     ;;; Find-Result-Type -- Internal
544     ;;;
545     ;;; This function is called on RETURN nodes that have their REOPTIMIZE flag
546     ;;; set. It iterates over the uses of the RESULT, looking for interesting
547 ram 1.46 ;;; stuff to update the TAIL-SET. If a use isn't a local call, then we union
548     ;;; its type together with the types of other such uses. We assign to the
549     ;;; RETURN-RESULT-TYPE the intersection of this type with the RESULT's asserted
550     ;;; type. We can make this intersection now (potentially before type checking)
551     ;;; because this assertion on the result will eventually be checked (if
552     ;;; appropriate.)
553 wlott 1.1 ;;;
554 ram 1.46 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV combination,
555     ;;; which may change the succesor of the call to be the called function, and if
556 ram 1.56 ;;; so, checks if the call can become an assignment. If we convert to an
557     ;;; assignment, we abort, since the RETURN has been deleted.
558 ram 1.46 ;;;
559     (defun find-result-type (node)
560 wlott 1.1 (declare (type creturn node))
561 ram 1.46 (let ((result (return-result node)))
562 wlott 1.1 (collect ((use-union *empty-type* values-type-union))
563     (do-uses (use result)
564 ram 1.34 (cond ((and (basic-combination-p use)
565 ram 1.46 (eq (basic-combination-kind use) :local))
566     (assert (eq (lambda-tail-set (node-home-lambda use))
567     (lambda-tail-set (combination-lambda use))))
568 ram 1.39 (when (combination-p use)
569 ram 1.56 (when (nth-value 1 (maybe-convert-tail-local-call use))
570     (return-from find-result-type (undefined-value)))))
571 ram 1.34 (t
572     (use-union (node-derived-type use)))))
573 dtc 1.70 (let ((int (values-type-intersection (continuation-asserted-type result)
574     (use-union))))
575 ram 1.46 (setf (return-result-type node) int))))
576     (undefined-value))
577 wlott 1.1
578    
579     ;;; IR1-Optimize-Return -- Internal
580     ;;;
581     ;;; Do stuff to realize that something has changed about the value delivered
582     ;;; to a return node. Since we consider the return values of all functions in
583     ;;; the tail set to be equivalent, this amounts to bringing the entire tail set
584     ;;; up to date. We iterate over the returns for all the functions in the tail
585     ;;; set, reanalyzing them all (not treating Node specially.)
586     ;;;
587     ;;; When we are done, we check if the new type is different from the old
588     ;;; TAIL-SET-TYPE. If so, we set the type and also reoptimize all the
589     ;;; continuations for references to functions in the tail set. This will
590     ;;; cause IR1-OPTIMIZE-COMBINATION to derive the new type as the results of the
591     ;;; calls.
592     ;;;
593     (defun ir1-optimize-return (node)
594     (declare (type creturn node))
595 ram 1.46 (let* ((tails (lambda-tail-set (return-lambda node)))
596     (funs (tail-set-functions tails)))
597 wlott 1.1 (collect ((res *empty-type* values-type-union))
598 ram 1.46 (dolist (fun funs)
599     (let ((return (lambda-return fun)))
600     (when return
601     (when (node-reoptimize return)
602 ram 1.58 (setf (node-reoptimize return) nil)
603 ram 1.46 (find-result-type return))
604     (res (return-result-type return)))))
605 wlott 1.1
606     (when (type/= (res) (tail-set-type tails))
607     (setf (tail-set-type tails) (res))
608     (dolist (fun (tail-set-functions tails))
609     (dolist (ref (leaf-refs fun))
610     (reoptimize-continuation (node-cont ref)))))))
611    
612     (undefined-value))
613    
614    
615 ram 1.50 ;;; IF optimization:
616    
617     (declaim (start-block ir1-optimize-if))
618    
619 wlott 1.1 ;;; IR1-Optimize-If -- Internal
620     ;;;
621     ;;; If the test has multiple uses, replicate the node when possible. Also
622     ;;; check if the predicate is known to be true or false, deleting the IF node
623     ;;; in favor of the appropriate branch when this is the case.
624     ;;;
625     (defun ir1-optimize-if (node)
626     (declare (type cif node))
627     (let ((test (if-test node))
628     (block (node-block node)))
629    
630     (when (and (eq (block-start block) test)
631     (eq (continuation-next test) node)
632     (rest (block-start-uses block)))
633     (do-uses (use test)
634     (when (immediately-used-p test use)
635     (convert-if-if use node)
636     (when (continuation-use test) (return)))))
637 gerd 1.77 ;;
638     ;; Don't flush if-tests when they require a type check.
639     (when (memq (continuation-type-check test) '(nil :deleted))
640     (let* ((type (continuation-type test))
641     (victim
642     (cond ((constant-continuation-p test)
643     (if (continuation-value test)
644     (if-alternative node)
645     (if-consequent node)))
646     ((not (types-intersect type *null-type*))
647     (if-alternative node))
648     ((type= type *null-type*)
649     (if-consequent node)))))
650     (when victim
651     (flush-dest test)
652     (when (rest (block-succ block))
653     (unlink-blocks block victim))
654     (setf (component-reanalyze (block-component (node-block node))) t)
655     (unlink-node node)))))
656 wlott 1.1 (undefined-value))
657    
658    
659     ;;; Convert-If-If -- Internal
660     ;;;
661     ;;; Create a new copy of an IF Node that tests the value of the node Use.
662     ;;; The test must have >1 use, and must be immediately used by Use. Node must
663     ;;; be the only node in its block (implying that block-start = if-test).
664     ;;;
665     ;;; This optimization has an effect semantically similar to the
666     ;;; source-to-source transformation:
667     ;;; (IF (IF A B C) D E) ==>
668     ;;; (IF A (IF B D E) (IF C D E))
669     ;;;
670 ram 1.55 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new node so
671     ;;; that dead code deletion notes will definitely not consider either node to
672     ;;; be part of the original source. One node might become unreachable,
673     ;;; resulting in a spurious note.
674     ;;;
675 wlott 1.1 (defun convert-if-if (use node)
676     (declare (type node use) (type cif node))
677     (with-ir1-environment node
678     (let* ((block (node-block node))
679     (test (if-test node))
680     (cblock (if-consequent node))
681     (ablock (if-alternative node))
682     (use-block (node-block use))
683     (dummy-cont (make-continuation))
684     (new-cont (make-continuation))
685 ram 1.11 (new-node (make-if :test new-cont
686 wlott 1.1 :consequent cblock :alternative ablock))
687     (new-block (continuation-starts-block new-cont)))
688     (prev-link new-node new-cont)
689     (setf (continuation-dest new-cont) new-node)
690     (add-continuation-use new-node dummy-cont)
691     (setf (block-last new-block) new-node)
692    
693     (unlink-blocks use-block block)
694     (delete-continuation-use use)
695     (add-continuation-use use new-cont)
696     (link-blocks use-block new-block)
697    
698     (link-blocks new-block cblock)
699     (link-blocks new-block ablock)
700 ram 1.55
701     (push "<IF Duplication>" (node-source-path node))
702     (push "<IF Duplication>" (node-source-path new-node))
703 wlott 1.1
704     (reoptimize-continuation test)
705     (reoptimize-continuation new-cont)
706     (setf (component-reanalyze *current-component*) t)))
707     (undefined-value))
708    
709 ram 1.50 (declaim (end-block))
710    
711 wlott 1.1
712     ;;;; Exit IR1 optimization:
713    
714     ;;; Maybe-Delete-Exit -- Interface
715     ;;;
716     ;;; This function attempts to delete an exit node, returning true if it
717     ;;; deletes the block as a consequence:
718     ;;; -- If the exit is degenerate (has no Entry), then we don't do anything,
719     ;;; since there is nothing to be done.
720     ;;; -- If the exit node and its Entry have the same home lambda then we know
721     ;;; the exit is local, and can delete the exit. We change uses of the
722     ;;; Exit-Value to be uses of the original continuation, then unlink the
723 ram 1.46 ;;; node. If the exit is to a TR context, then we must do MERGE-TAIL-SETS
724     ;;; on any local calls which delivered their value to this exit.
725 wlott 1.1 ;;; -- If there is no value (as in a GO), then we skip the value semantics.
726     ;;;
727     ;;; This function is also called by environment analysis, since it wants all
728     ;;; exits to be optimized even if normal optimization was omitted.
729     ;;;
730     (defun maybe-delete-exit (node)
731     (declare (type exit node))
732     (let ((value (exit-value node))
733     (entry (exit-entry node))
734     (cont (node-cont node)))
735     (when (and entry
736 ram 1.11 (eq (node-home-lambda node) (node-home-lambda entry)))
737     (setf (entry-exits entry) (delete node (entry-exits entry)))
738 wlott 1.1 (prog1
739     (unlink-node node)
740     (when value
741 ram 1.46 (collect ((merges))
742     (when (return-p (continuation-dest cont))
743     (do-uses (use value)
744     (when (and (basic-combination-p use)
745     (eq (basic-combination-kind use) :local))
746     (merges use))))
747     (substitute-continuation-uses cont value)
748     (dolist (merge (merges))
749     (merge-tail-sets merge))))))))
750 wlott 1.1
751    
752     ;;;; Combination IR1 optimization:
753    
754 ram 1.50 (declaim (start-block ir1-optimize-combination maybe-terminate-block
755     validate-call-type))
756    
757 wlott 1.1 ;;; Ir1-Optimize-Combination -- Internal
758     ;;;
759     ;;; Do IR1 optimizations on a Combination node.
760     ;;;
761     (defun ir1-optimize-combination (node)
762 dtc 1.71 (declare (type combination node))
763 ram 1.50 (when (continuation-reoptimize (basic-combination-fun node))
764     (propagate-function-change node))
765 wlott 1.1 (let ((args (basic-combination-args node))
766     (kind (basic-combination-kind node)))
767     (case kind
768     (:local
769     (let ((fun (combination-lambda node)))
770     (if (eq (functional-kind fun) :let)
771     (propagate-let-args node fun)
772     (propagate-local-call-args node fun))))
773 ram 1.50 ((:full :error)
774 wlott 1.1 (dolist (arg args)
775     (when arg
776     (setf (continuation-reoptimize arg) nil))))
777     (t
778     (dolist (arg args)
779     (when arg
780     (setf (continuation-reoptimize arg) nil)))
781    
782     (let ((attr (function-info-attributes kind)))
783     (when (and (ir1-attributep attr foldable)
784     (not (ir1-attributep attr call))
785     (every #'constant-continuation-p args)
786     (continuation-dest (node-cont node)))
787     (constant-fold-call node)
788     (return-from ir1-optimize-combination)))
789 ram 1.18
790 wlott 1.1 (let ((fun (function-info-derive-type kind)))
791     (when fun
792     (let ((res (funcall fun node)))
793     (when res
794 ram 1.50 (derive-node-type node res)
795     (maybe-terminate-block node nil)))))
796 ram 1.18
797 wlott 1.1 (let ((fun (function-info-optimizer kind)))
798     (unless (and fun (funcall fun node))
799     (dolist (x (function-info-transforms kind))
800 ram 1.28 (unless (ir1-transform node x)
801 wlott 1.2 (return))))))))
802 wlott 1.1
803     (undefined-value))
804    
805    
806 ram 1.29 ;;; MAYBE-TERMINATE-BLOCK -- Interface
807     ;;;
808     ;;; If Call is to a function that doesn't return (type NIL), then terminate
809 ram 1.31 ;;; the block there, and link it to the component tail. We also change the
810     ;;; call's CONT to be a dummy continuation to prevent the use from confusing
811     ;;; things.
812 ram 1.29 ;;;
813 ram 1.30 ;;; Except when called during IR1, we delete the continuation if it has no
814     ;;; other uses. (If it does have other uses, we reoptimize.)
815     ;;;
816 ram 1.31 ;;; Termination on the basis of a continuation type assertion is inhibited
817     ;;; when:
818     ;;; -- The continuation is deleted (hence the assertion is spurious), or
819     ;;; -- We are in IR1 conversion (where THE assertions are subject to
820     ;;; weakening.)
821     ;;;
822 ram 1.30 (defun maybe-terminate-block (call ir1-p)
823 ram 1.29 (declare (type basic-combination call))
824 ram 1.32 (let* ((block (node-block call))
825     (cont (node-cont call))
826     (tail (component-tail (block-component block)))
827     (succ (first (block-succ block))))
828     (unless (or (and (eq call (block-last block)) (eq succ tail))
829 ram 1.50 (block-delete-p block)
830     *converting-for-interpreter*)
831 ram 1.32 (when (or (and (eq (continuation-asserted-type cont) *empty-type*)
832     (not (or ir1-p (eq (continuation-kind cont) :deleted))))
833     (eq (node-derived-type call) *empty-type*))
834     (cond (ir1-p
835     (delete-continuation-use call)
836     (cond
837     ((block-last block)
838     (assert (and (eq (block-last block) call)
839     (eq (continuation-kind cont) :block-start))))
840     (t
841     (setf (block-last block) call)
842     (link-blocks block (continuation-starts-block cont)))))
843 ram 1.30 (t
844 ram 1.32 (node-ends-block call)
845     (delete-continuation-use call)
846     (if (eq (continuation-kind cont) :unused)
847     (delete-continuation cont)
848     (reoptimize-continuation cont))))
849    
850     (unlink-blocks block (first (block-succ block)))
851 ram 1.45 (setf (component-reanalyze (block-component block)) t)
852 ram 1.32 (assert (not (block-succ block)))
853     (link-blocks block tail)
854     (add-continuation-use call (make-continuation))
855     t))))
856 ram 1.30
857 ram 1.29
858 wlott 1.1 ;;; Recognize-Known-Call -- Interface
859     ;;;
860 ram 1.50 ;;; Called both by IR1 conversion and IR1 optimization when they have
861     ;;; verified the type signature for the call, and are wondering if something
862     ;;; should be done to special-case the call. If Call is a call to a global
863     ;;; function, then see if it defined or known:
864     ;;; -- If a DEFINED-FUNCTION should be inline expanded, then convert the
865     ;;; expansion and change the call to call it. Expansion is enabled if
866     ;;; :INLINE or if space=0. If the FUNCTIONAL slot is true, we never expand,
867     ;;; since this function has already been converted. Local call analysis
868     ;;; will duplicate the definition if necessary. We claim that the parent
869     ;;; form is LABELS for context declarations, since we don't want it to be
870     ;;; considered a real global function.
871     ;;; -- In addition to a direct check for the function name in the table, we
872     ;;; also must check for slot accessors. If the function is a slot accessor,
873     ;;; then we set the combination kind to the function info of %Slot-Setter or
874     ;;; %Slot-Accessor, as appropriate.
875     ;;; -- If it is a known function, mark it as such by setting the Kind.
876 wlott 1.1 ;;;
877 ram 1.50 ;;; We return the leaf referenced (NIL if not a leaf) and the function-info
878     ;;; assigned.
879 ram 1.19 ;;;
880 ram 1.50 (defun recognize-known-call (call ir1-p)
881 wlott 1.1 (declare (type combination call))
882 ram 1.50 (let* ((ref (continuation-use (basic-combination-fun call)))
883     (leaf (when (ref-p ref) (ref-leaf ref)))
884 ram 1.60 (inlinep (if (and (defined-function-p leaf)
885 gerd 1.75 (not (byte-compiling))
886     (not *converting-for-interpreter*))
887 ram 1.50 (defined-function-inlinep leaf)
888     :no-chance)))
889     (cond
890     ((eq inlinep :notinline) (values nil nil))
891     ((not (and (global-var-p leaf)
892     (eq (global-var-kind leaf) :global-function)))
893     (values leaf nil))
894     ((and (ecase inlinep
895     (:inline t)
896     (:no-chance nil)
897     ((nil :maybe-inline) (policy call (zerop space))))
898     (defined-function-inline-expansion leaf)
899     (let ((fun (defined-function-functional leaf)))
900     (or (not fun)
901     (and (eq inlinep :inline) (functional-kind fun))))
902     (inline-expansion-ok call))
903     (flet ((frob ()
904     (let ((res (ir1-convert-lambda-for-defun
905     (defined-function-inline-expansion leaf)
906 ram 1.53 leaf t
907 ram 1.50 #'ir1-convert-inline-lambda
908     'labels)))
909     (setf (defined-function-functional leaf) res)
910     (change-ref-leaf ref res))))
911     (if ir1-p
912     (frob)
913     (with-ir1-environment call
914     (frob)
915     (local-call-analyze *current-component*))))
916 ram 1.53
917 ram 1.50 (values (ref-leaf (continuation-use (basic-combination-fun call)))
918     nil))
919     (t
920     (let* ((name (leaf-name leaf))
921 pw 1.67 (info (info function info
922     (if (slot-accessor-p leaf)
923     (if (consp name)
924     '%slot-setter
925     '%slot-accessor)
926     name))))
927 ram 1.50 (if info
928     (values leaf (setf (basic-combination-kind call) info))
929     (values leaf nil)))))))
930 wlott 1.1
931    
932 ram 1.50 ;;; VALIDATE-CALL-TYPE -- Internal
933     ;;;
934     ;;; Check if Call satisfies Type. If so, apply the type to the call, and do
935     ;;; MAYBE-TERMINATE-BLOCK and return the values of RECOGNIZE-KNOWN-CALL. If an
936 ram 1.57 ;;; error, set the combination kind and return NIL, NIL. If the type is just
937     ;;; FUNCTION, then skip the syntax check, arg/result type processing, but still
938     ;;; call RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda, and
939     ;;; that checking is done by local call analysis.
940 ram 1.50 ;;;
941     (defun validate-call-type (call type ir1-p)
942     (declare (type combination call) (type ctype type))
943 ram 1.57 (cond ((not (function-type-p type))
944     (assert (multiple-value-bind
945     (val win)
946     (csubtypep type (specifier-type 'function))
947     (or val (not win))))
948     (recognize-known-call call ir1-p))
949 ram 1.50 ((valid-function-use call type
950     :argument-test #'always-subtypep
951     :result-test #'always-subtypep
952     :error-function #'compiler-warning
953     :warning-function #'compiler-note)
954     (assert-call-type call type)
955     (maybe-terminate-block call ir1-p)
956     (recognize-known-call call ir1-p))
957     (t
958     (setf (combination-kind call) :error)
959     (values nil nil))))
960    
961    
962 wlott 1.1 ;;; Propagate-Function-Change -- Internal
963     ;;;
964     ;;; Called by Ir1-Optimize when the function for a call has changed.
965 ram 1.50 ;;; If the call is local, we try to let-convert it, and derive the result type.
966     ;;; If it is a :FULL call, we validate it against the type, which recognizes
967     ;;; known calls, does inline expansion, etc. If a call to a predicate in a
968     ;;; non-conditional position or to a function with a source transform, then we
969     ;;; reconvert the form to give IR1 another chance.
970 wlott 1.1 ;;;
971     (defun propagate-function-change (call)
972     (declare (type combination call))
973 ram 1.50 (let ((*compiler-error-context* call)
974     (fun-cont (basic-combination-fun call)))
975     (setf (continuation-reoptimize fun-cont) nil)
976     (case (combination-kind call)
977     (:local
978     (let ((fun (combination-lambda call)))
979     (maybe-let-convert fun)
980     (unless (member (functional-kind fun) '(:let :assignment :deleted))
981     (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
982     (:full
983     (multiple-value-bind
984     (leaf info)
985 ram 1.59 (validate-call-type call (continuation-type fun-cont) nil)
986 ram 1.50 (cond ((functional-p leaf)
987     (convert-call-if-possible
988     (continuation-use (basic-combination-fun call))
989     call))
990     ((not leaf))
991     ((or (info function source-transform (leaf-name leaf))
992     (and info
993     (ir1-attributep (function-info-attributes info)
994     predicate)
995     (let ((dest (continuation-dest (node-cont call))))
996     (and dest (not (if-p dest))))))
997     (let ((name (leaf-name leaf)))
998     (when (symbolp name)
999     (let ((dums (loop repeat (length (combination-args call))
1000     collect (gensym))))
1001     (transform-call call
1002     `(lambda ,dums
1003     (,name ,@dums))))))))))))
1004 wlott 1.1 (undefined-value))
1005    
1006    
1007     ;;;; Known function optimization:
1008    
1009 ram 1.15
1010     ;;; RECORD-OPTIMIZATION-FAILURE -- Internal
1011     ;;;
1012 ram 1.50 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for Node, Fun
1013 ram 1.28 ;;; and Args. If there is already a note for Node and Transform, replace it,
1014 ram 1.15 ;;; otherwise add a new one.
1015     ;;;
1016 ram 1.28 (defun record-optimization-failure (node transform args)
1017     (declare (type combination node) (type transform transform)
1018 ram 1.15 (type (or function-type list) args))
1019 ram 1.50 (let* ((table (component-failed-optimizations *compile-component*))
1020     (found (assoc transform (gethash node table))))
1021 ram 1.15 (if found
1022     (setf (cdr found) args)
1023 ram 1.50 (push (cons transform args) (gethash node table))))
1024 ram 1.15 (undefined-value))
1025    
1026    
1027 wlott 1.1 ;;; IR1-Transform -- Internal
1028     ;;;
1029     ;;; Attempt to transform Node using Function, subject to the call type
1030     ;;; constraint Type. If we are inhibited from doing the transform for some
1031     ;;; reason and Flame is true, then we make a note of the message in
1032 ram 1.50 ;;; FAILED-OPTIMIZATIONS for IR1 finalize to pick up. We return true if
1033 wlott 1.2 ;;; the transform failed, and thus further transformation should be
1034     ;;; attempted. We return false if either the transform suceeded or was
1035     ;;; aborted.
1036 wlott 1.1 ;;;
1037 ram 1.28 (defun ir1-transform (node transform)
1038     (declare (type combination node) (type transform transform))
1039     (let* ((type (transform-type transform))
1040     (fun (transform-function transform))
1041     (constrained (function-type-p type))
1042 ram 1.50 (table (component-failed-optimizations *compile-component*))
1043 wlott 1.41 (flame
1044     (if (transform-important transform)
1045     (policy node (>= speed brevity))
1046     (policy node (> speed brevity))))
1047 ram 1.28 (*compiler-error-context* node))
1048 ram 1.60 (cond ((let ((when (transform-when transform)))
1049     (not (or (eq when :both)
1050     (eq when (if *byte-compiling* :byte :native)))))
1051     t)
1052     ((or (not constrained)
1053 ram 1.19 (valid-function-use node type :strict-result t))
1054 wlott 1.1 (multiple-value-bind
1055     (severity args)
1056     (catch 'give-up
1057     (transform-call node (funcall fun node))
1058     (values :none nil))
1059     (ecase severity
1060 ram 1.15 (:none
1061 ram 1.50 (remhash node table)
1062 ram 1.15 nil)
1063 wlott 1.1 (:aborted
1064 ram 1.50 (setf (combination-kind node) :error)
1065 wlott 1.1 (when args
1066 wlott 1.2 (apply #'compiler-warning args))
1067 ram 1.50 (remhash node table)
1068 wlott 1.2 nil)
1069 wlott 1.1 (:failure
1070 ram 1.15 (if args
1071     (when flame
1072 ram 1.28 (record-optimization-failure node transform args))
1073 ram 1.50 (setf (gethash node table)
1074     (remove transform (gethash node table) :key #'car)))
1075 dtc 1.72 t)
1076     (:delayed
1077     (remhash node table)
1078     nil))))
1079 wlott 1.1 ((and flame
1080     (valid-function-use node type
1081     :argument-test #'types-intersect
1082     :result-test #'values-types-intersect))
1083 ram 1.28 (record-optimization-failure node transform type)
1084 wlott 1.13 t)
1085     (t
1086 wlott 1.2 t))))
1087 wlott 1.1
1088 ram 1.50 (declaim (end-block))
1089 wlott 1.1
1090 dtc 1.72 ;;; give-up, abort-transform -- Interface
1091 wlott 1.1 ;;;
1092     ;;; Just throw the severity and args...
1093     ;;;
1094     (defun give-up (&rest args)
1095     "This function is used to throw out of an IR1 transform, aborting this
1096     attempt to transform the call, but admitting the possibility that this or
1097     some other transform will later suceed. If arguments are supplied, they are
1098     format arguments for an efficiency note."
1099 dtc 1.71 (values nil)
1100 wlott 1.1 (throw 'give-up (values :failure args)))
1101     ;;;
1102     (defun abort-transform (&rest args)
1103     "This function is used to throw out of an IR1 transform and force a normal
1104     call to the function at run time. No further optimizations will be
1105     attempted."
1106     (throw 'give-up (values :aborted args)))
1107 dtc 1.72
1108     (defvar *delayed-transforms*)
1109    
1110     ;;; delay-transform -- Interface
1111     ;;;
1112     (defun delay-transform (node &rest reasons)
1113     "This function is used to throw out of an IR1 transform, and delay the
1114     transform on the node until later. The reasons specifies when the transform
1115     will be later retried. The :optimize reason causes the transform to be
1116     delayed until after the current IR1 optimization pass. The :constraint
1117     reason causes the transform to be delayed until after constraint
1118     propagation."
1119     (let ((assoc (assoc node *delayed-transforms*)))
1120     (cond ((not assoc)
1121     (setf *delayed-transforms*
1122     (acons node reasons *delayed-transforms*))
1123     (throw 'give-up :delayed))
1124     ((cdr assoc)
1125     (dolist (reason reasons)
1126     (pushnew reason (cdr assoc)))
1127     (throw 'give-up :delayed)))))
1128    
1129     ;;; retry-delayed-transforms -- Interface.
1130     ;;;
1131     ;;; Clear any delayed transform with no reasons - these should have been tried
1132     ;;; in the last pass. Then remove the reason from the delayed transform
1133     ;;; reasons, and if any become empty then set reoptimize flags for the
1134     ;;; node. Returns true if any transforms are to be retried.
1135     ;;;
1136     (defun retry-delayed-transforms (reason)
1137     (setf *delayed-transforms* (remove-if-not #'cdr *delayed-transforms*))
1138     (let ((reoptimize nil))
1139     (dolist (assoc *delayed-transforms*)
1140     (let ((reasons (remove reason (cdr assoc))))
1141     (setf (cdr assoc) reasons)
1142     (unless reasons
1143     (let ((node (car assoc)))
1144     (unless (node-deleted node)
1145     (setf reoptimize t)
1146     (setf (node-reoptimize node) t)
1147     (let ((block (node-block node)))
1148     (setf (block-reoptimize block) t)
1149     (setf (component-reoptimize (block-component block)) t)))))))
1150     reoptimize))
1151 wlott 1.1
1152    
1153     ;;; Transform-Call -- Internal
1154     ;;;
1155     ;;; Take the lambda-expression Res, IR1 convert it in the proper
1156     ;;; environment, and then install it as the function for the call Node. We do
1157     ;;; local call analysis so that the new function is integrated into the control
1158 ram 1.50 ;;; flow.
1159 wlott 1.1 ;;;
1160     (defun transform-call (node res)
1161     (declare (type combination node) (list res))
1162     (with-ir1-environment node
1163 ram 1.50 (let ((new-fun (ir1-convert-inline-lambda res))
1164 wlott 1.1 (ref (continuation-use (combination-fun node))))
1165     (change-ref-leaf ref new-fun)
1166     (setf (combination-kind node) :full)
1167     (local-call-analyze *current-component*)))
1168     (undefined-value))
1169    
1170     ;;; Constant-Fold-Call -- Internal
1171     ;;;
1172     ;;; Replace a call to a foldable function of constant arguments with the
1173     ;;; result of evaluating the form. We insert the resulting constant node after
1174     ;;; the call, stealing the call's continuation. We give the call a
1175     ;;; continuation with no Dest, which should cause it and its arguments to go
1176     ;;; away. If there is an error during the evaluation, we give a warning and
1177 ram 1.50 ;;; leave the call alone, making the call a :ERROR call.
1178 wlott 1.1 ;;;
1179 ram 1.50 ;;; If there is more than one value, then we transform the call into a
1180     ;;; values form.
1181 wlott 1.1 ;;;
1182     (defun constant-fold-call (call)
1183     (declare (type combination call))
1184     (let* ((args (mapcar #'continuation-value (combination-args call)))
1185     (ref (continuation-use (combination-fun call)))
1186     (fun (leaf-name (ref-leaf ref))))
1187    
1188     (multiple-value-bind (values win)
1189 gerd 1.77 (careful-call fun args call "constant folding")
1190     (cond ((not win)
1191     (setf (combination-kind call) :error))
1192     ;;
1193     ;; Don't constand-fold a call if one of its arguments
1194     ;; requires a type check.
1195     ((or (policy call (< safety 3))
1196     (loop for arg in (basic-combination-args call)
1197     as check = (continuation-type-check arg)
1198     always (member check '(nil :deleted))))
1199     (let ((dummies (loop repeat (length args) collect (gensym))))
1200     (transform-call
1201     call
1202     `(lambda ,dummies
1203     (declare (ignore ,@dummies))
1204     (values ,@(mapcar (lambda (x) `',x) values)))))))))
1205     (values))
1206 wlott 1.1
1207    
1208     ;;;; Local call optimization:
1209    
1210 ram 1.50 (declaim (start-block ir1-optimize-set constant-reference-p delete-let
1211     propagate-let-args propagate-local-call-args
1212 ram 1.52 propagate-to-refs propagate-from-sets
1213     ir1-optimize-mv-combination))
1214 ram 1.50
1215 wlott 1.1 ;;; Propagate-To-Refs -- Internal
1216     ;;;
1217     ;;; Propagate Type to Leaf and its Refs, marking things changed. If the
1218     ;;; leaf type is a function type, then just leave it alone, since TYPE is never
1219     ;;; going to be more specific than that (and TYPE-INTERSECTION would choke.)
1220     ;;;
1221     (defun propagate-to-refs (leaf type)
1222     (declare (type leaf leaf) (type ctype type))
1223     (let ((var-type (leaf-type leaf)))
1224     (unless (function-type-p var-type)
1225     (let ((int (type-intersection var-type type)))
1226     (when (type/= int var-type)
1227     (setf (leaf-type leaf) int)
1228     (dolist (ref (leaf-refs leaf))
1229     (derive-node-type ref int))))
1230     (undefined-value))))
1231    
1232    
1233     ;;; PROPAGATE-FROM-SETS -- Internal
1234     ;;;
1235     ;;; Figure out the type of a LET variable that has sets. We compute the
1236     ;;; union of the initial value Type and the types of all the set values and to
1237     ;;; a PROPAGATE-TO-REFS with this type.
1238     ;;;
1239     (defun propagate-from-sets (var type)
1240 ram 1.6 (collect ((res type type-union))
1241 wlott 1.1 (dolist (set (basic-var-sets var))
1242     (res (continuation-type (set-value set)))
1243     (setf (node-reoptimize set) nil))
1244     (propagate-to-refs var (res)))
1245     (undefined-value))
1246    
1247    
1248     ;;; IR1-OPTIMIZE-SET -- Internal
1249     ;;;
1250     ;;; If a let variable, find the initial value's type and do
1251     ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's type.
1252     ;;;
1253     (defun ir1-optimize-set (node)
1254     (declare (type cset node))
1255     (let ((var (set-var node)))
1256     (when (and (lambda-var-p var) (leaf-refs var))
1257     (let ((home (lambda-var-home var)))
1258     (when (eq (functional-kind home) :let)
1259     (let ((iv (let-var-initial-value var)))
1260     (setf (continuation-reoptimize iv) nil)
1261     (propagate-from-sets var (continuation-type iv)))))))
1262    
1263     (derive-node-type node (continuation-type (set-value node)))
1264     (undefined-value))
1265    
1266    
1267 ram 1.17 ;;; CONSTANT-REFERENCE-P -- Interface
1268 ram 1.7 ;;;
1269     ;;; Return true if the value of Ref will always be the same (and is thus
1270 ram 1.50 ;;; legal to substitute.)
1271 ram 1.7 ;;;
1272     (defun constant-reference-p (ref)
1273     (declare (type ref ref))
1274     (let ((leaf (ref-leaf ref)))
1275     (typecase leaf
1276 ram 1.50 ((or constant functional) t)
1277 ram 1.7 (lambda-var
1278     (null (lambda-var-sets leaf)))
1279 ram 1.50 (defined-function
1280     (not (eq (defined-function-inlinep leaf) :notinline)))
1281 ram 1.7 (global-var
1282     (case (global-var-kind leaf)
1283 ram 1.50 (:global-function t)
1284 ram 1.7 (:constant t))))))
1285    
1286    
1287     ;;; SUBSTITUTE-SINGLE-USE-CONTINUATION -- Internal
1288     ;;;
1289     ;;; If we have a non-set let var with a single use, then (if possible)
1290     ;;; replace the variable reference's CONT with the arg continuation. This is
1291     ;;; inhibited when:
1292     ;;; -- CONT has other uses, or
1293     ;;; -- CONT receives multiple values, or
1294 ram 1.9 ;;; -- the reference is in a different environment from the variable, or
1295     ;;; -- either continuation has a funky TYPE-CHECK annotation.
1296 ram 1.43 ;;; -- the continuations have incompatible assertions, so the new asserted type
1297     ;;; would be NIL.
1298 dtc 1.68 ;;; -- CONT's assertion is incompatbile with the proven type of ARG's, such as
1299     ;;; when ARG returns multiple values and CONT has a single value assertion.
1300 ram 1.27 ;;; -- the var's DEST has a different policy than the ARG's (think safety).
1301 ram 1.7 ;;;
1302     ;;; We change the Ref to be a reference to NIL with unused value, and let it
1303     ;;; be flushed as dead code. A side-effect of this substitution is to delete
1304     ;;; the variable.
1305     ;;;
1306     (defun substitute-single-use-continuation (arg var)
1307     (declare (type continuation arg) (type lambda-var var))
1308     (let* ((ref (first (leaf-refs var)))
1309     (cont (node-cont ref))
1310 ram 1.43 (cont-atype (continuation-asserted-type cont))
1311 ram 1.7 (dest (continuation-dest cont)))
1312     (when (and (eq (continuation-use cont) ref)
1313     dest
1314     (not (typep dest '(or creturn exit mv-combination)))
1315 ram 1.11 (eq (node-home-lambda ref)
1316 ram 1.9 (lambda-home (lambda-var-home var)))
1317     (member (continuation-type-check arg) '(t nil))
1318 ram 1.27 (member (continuation-type-check cont) '(t nil))
1319 ram 1.43 (not (eq (values-type-intersection
1320 dtc 1.68 cont-atype (continuation-asserted-type arg))
1321     *empty-type*))
1322     (not (eq (values-type-intersection
1323     cont-atype (continuation-proven-type arg))
1324 ram 1.43 *empty-type*))
1325 ram 1.27 (eq (lexenv-cookie (node-lexenv dest))
1326     (lexenv-cookie (node-lexenv (continuation-dest arg)))))
1327 ram 1.25 (assert (member (continuation-kind arg)
1328     '(:block-start :deleted-block-start :inside-block)))
1329 ram 1.43 (assert-continuation-type arg cont-atype)
1330 ram 1.34 (setf (node-derived-type ref) *wild-type*)
1331 ram 1.7 (change-ref-leaf ref (find-constant nil))
1332     (substitute-continuation arg cont)
1333     (reoptimize-continuation arg)
1334     t)))
1335    
1336    
1337 ram 1.19 ;;; DELETE-LET -- Interface
1338     ;;;
1339     ;;; Delete a Let, removing the call and bind nodes, and warning about any
1340     ;;; unreferenced variables. Note that FLUSH-DEAD-CODE will come along right
1341     ;;; away and delete the REF and then the lambda, since we flush the FUN
1342     ;;; continuation.
1343     ;;;
1344     (defun delete-let (fun)
1345     (declare (type clambda fun))
1346 ram 1.42 (assert (member (functional-kind fun) '(:let :mv-let)))
1347 ram 1.19 (note-unreferenced-vars fun)
1348     (let ((call (let-combination fun)))
1349 ram 1.42 (flush-dest (basic-combination-fun call))
1350 ram 1.19 (unlink-node call)
1351     (unlink-node (lambda-bind fun))
1352     (setf (lambda-bind fun) nil))
1353     (undefined-value))
1354    
1355    
1356 wlott 1.1 ;;; Propagate-Let-Args -- Internal
1357     ;;;
1358     ;;; This function is called when one of the arguments to a LET changes. We
1359     ;;; look at each changed argument. If the corresponding variable is set, then
1360     ;;; we call PROPAGATE-FROM-SETS. Otherwise, we consider substituting for the
1361     ;;; variable, and also propagate derived-type information for the arg to all
1362     ;;; the Var's refs.
1363     ;;;
1364 ram 1.16 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1365     ;;; subtype of the argument's asserted type. This prevents type checking from
1366     ;;; being defeated, and also ensures that the best representation for the
1367     ;;; variable can be used.
1368 wlott 1.1 ;;;
1369 ram 1.26 ;;; Substitution of individual references is inhibited if the reference is
1370     ;;; in a different component from the home. This can only happen with closures
1371     ;;; over top-level lambda vars. In such cases, the references may have already
1372     ;;; been compiled, and thus can't be retroactively modified.
1373     ;;;
1374 dtc 1.73 ;;; If all of the variables are deleted (have no references) when we are
1375     ;;; done, then we delete the let.
1376 ram 1.19 ;;;
1377 wlott 1.1 ;;; Note that we are responsible for clearing the Continuation-Reoptimize
1378     ;;; flags.
1379     ;;;
1380     (defun propagate-let-args (call fun)
1381     (declare (type combination call) (type clambda fun))
1382 ram 1.19 (loop for arg in (combination-args call)
1383     and var in (lambda-vars fun) do
1384     (when (and arg (continuation-reoptimize arg))
1385     (setf (continuation-reoptimize arg) nil)
1386     (cond
1387     ((lambda-var-sets var)
1388     (propagate-from-sets var (continuation-type arg)))
1389     ((let ((use (continuation-use arg)))
1390     (when (ref-p use)
1391     (let ((leaf (ref-leaf use)))
1392     (when (and (constant-reference-p use)
1393     (values-subtypep (leaf-type leaf)
1394     (continuation-asserted-type arg)))
1395     (propagate-to-refs var (continuation-type arg))
1396 ram 1.26 (let ((this-comp (block-component (node-block use))))
1397     (substitute-leaf-if
1398     #'(lambda (ref)
1399     (cond ((eq (block-component (node-block ref))
1400     this-comp)
1401     t)
1402     (t
1403     (assert (eq (functional-kind (lambda-home fun))
1404     :top-level))
1405     nil)))
1406     leaf var))
1407 ram 1.19 t)))))
1408     ((and (null (rest (leaf-refs var)))
1409 wlott 1.47 (not *byte-compiling*)
1410 ram 1.19 (substitute-single-use-continuation arg var)))
1411     (t
1412     (propagate-to-refs var (continuation-type arg))))))
1413 dtc 1.73
1414     (when (every #'null (combination-args call))
1415 ram 1.19 (delete-let fun))
1416    
1417 wlott 1.1 (undefined-value))
1418    
1419    
1420     ;;; Propagate-Local-Call-Args -- Internal
1421     ;;;
1422     ;;; This function is called when one of the args to a non-let local call
1423     ;;; changes. For each changed argument corresponding to an unset variable, we
1424     ;;; compute the union of the types across all calls and propagate this type
1425     ;;; information to the var's refs.
1426     ;;;
1427     ;;; If the function has an XEP, then we don't do anything, since we won't
1428     ;;; discover anything.
1429     ;;;
1430     ;;; We can clear the Continuation-Reoptimize flags for arguments in all calls
1431     ;;; corresponding to changed arguments in Call, since the only use in IR1
1432     ;;; optimization of the Reoptimize flag for local call args is right here.
1433     ;;;
1434     (defun propagate-local-call-args (call fun)
1435     (declare (type combination call) (type clambda fun))
1436    
1437 ram 1.64 (unless (or (functional-entry-function fun)
1438     (lambda-optional-dispatch fun))
1439 wlott 1.1 (let* ((vars (lambda-vars fun))
1440     (union (mapcar #'(lambda (arg var)
1441     (when (and arg
1442     (continuation-reoptimize arg)
1443     (null (basic-var-sets var)))
1444     (continuation-type arg)))
1445     (basic-combination-args call)
1446     vars))
1447     (this-ref (continuation-use (basic-combination-fun call))))
1448    
1449     (dolist (arg (basic-combination-args call))
1450     (when arg
1451     (setf (continuation-reoptimize arg) nil)))
1452    
1453     (dolist (ref (leaf-refs fun))
1454 ram 1.63 (let ((dest (continuation-dest (node-cont ref))))
1455     (unless (or (eq ref this-ref) (not dest))
1456     (setq union
1457     (mapcar #'(lambda (this-arg old)
1458     (when old
1459     (setf (continuation-reoptimize this-arg) nil)
1460     (type-union (continuation-type this-arg) old)))
1461     (basic-combination-args dest)
1462     union)))))
1463 wlott 1.1
1464     (mapc #'(lambda (var type)
1465     (when type
1466     (propagate-to-refs var type)))
1467     vars union)))
1468    
1469 ram 1.6 (undefined-value))
1470    
1471 ram 1.50 (declaim (end-block))
1472    
1473 ram 1.6
1474 ram 1.19 ;;;; Multiple values optimization:
1475    
1476 ram 1.21 ;;; IR1-OPTIMIZE-MV-COMBINATION -- Internal
1477     ;;;
1478 ram 1.32 ;;; Do stuff to notice a change to a MV combination node. There are two
1479     ;;; main branches here:
1480     ;;; -- If the call is local, then it is already a MV let, or should become one.
1481     ;;; Note that although all :LOCAL MV calls must eventually be converted to
1482     ;;; :MV-LETs, there can be a window when the call is local, but has not
1483     ;;; been let converted yet. This is because the entry-point lambdas may
1484     ;;; have stray references (in other entry points) that have not been
1485     ;;; deleted yet.
1486     ;;; -- The call is full. This case is somewhat similar to the non-MV
1487     ;;; combination optimization: we propagate return type information and
1488     ;;; notice non-returning calls. We also have an optimization
1489     ;;; which tries to convert MV-CALLs into MV-binds.
1490 ram 1.21 ;;;
1491     (defun ir1-optimize-mv-combination (node)
1492 ram 1.50 (ecase (basic-combination-kind node)
1493     (:local
1494 ram 1.54 (let ((fun-cont (basic-combination-fun node)))
1495     (when (continuation-reoptimize fun-cont)
1496     (setf (continuation-reoptimize fun-cont) nil)
1497 ram 1.50 (maybe-let-convert (combination-lambda node))))
1498     (setf (continuation-reoptimize (first (basic-combination-args node))) nil)
1499     (when (eq (functional-kind (combination-lambda node)) :mv-let)
1500     (unless (convert-mv-bind-to-let node)
1501     (ir1-optimize-mv-bind node))))
1502     (:full
1503     (let* ((fun (basic-combination-fun node))
1504     (fun-changed (continuation-reoptimize fun))
1505     (args (basic-combination-args node)))
1506     (when fun-changed
1507     (setf (continuation-reoptimize fun) nil)
1508     (let ((type (continuation-type fun)))
1509     (when (function-type-p type)
1510     (derive-node-type node (function-type-returns type))))
1511     (maybe-terminate-block node nil)
1512     (let ((use (continuation-use fun)))
1513     (when (and (ref-p use) (functional-p (ref-leaf use)))
1514     (convert-call-if-possible use node)
1515 ram 1.54 (when (eq (basic-combination-kind node) :local)
1516     (maybe-let-convert (ref-leaf use))))))
1517 ram 1.50 (unless (or (eq (basic-combination-kind node) :local)
1518     (eq (continuation-function-name fun) '%throw))
1519     (ir1-optimize-mv-call node))
1520     (dolist (arg args)
1521     (setf (continuation-reoptimize arg) nil))))
1522     (:error))
1523 ram 1.21 (undefined-value))
1524    
1525    
1526 dtc 1.69 ;;; Values-types-defaulted -- Internal
1527     ;;;
1528     ;;; Like values-types, but returns the types of the given number of
1529     ;;; arguments. If optional of rest values must be used then the union
1530     ;;; with the null type is computed in case of defaulting, and if no
1531     ;;; values are available then they are defaulted to the null type.
1532     ;;;
1533     (defun values-types-defaulted (type count)
1534     (declare (type ctype type) (type index count))
1535     (cond ((eq type *wild-type*)
1536     (let ((types nil))
1537     (dotimes (i count types)
1538     (push *universal-type* types))))
1539     ((not (values-type-p type))
1540     (let ((types nil))
1541     (dotimes (i (1- count))
1542     (push *null-type* types))
1543     (push type types)))
1544     (t
1545     (let ((required (args-type-required type))
1546     (optional (args-type-optional type))
1547     (keyp-allowp (or (args-type-keyp type) (args-type-allowp type)))
1548     (rest (args-type-rest type)))
1549     (collect ((types))
1550     (dotimes (i count)
1551     (types (cond (required (single-value-type (pop required)))
1552     (optional (values-type-union
1553     (single-value-type (pop optional))
1554     *null-type*))
1555     (keyp-allowp *universal-type*)
1556     (rest (values-type-union (single-value-type rest)
1557     *null-type*))
1558     (t *null-type*))))
1559     (types))))))
1560    
1561    
1562 ram 1.6 ;;; IR1-OPTIMIZE-MV-BIND -- Internal
1563     ;;;
1564     ;;; Propagate derived type info from the values continuation to the vars.
1565     ;;;
1566     (defun ir1-optimize-mv-bind (node)
1567     (declare (type mv-combination node))
1568     (let ((arg (first (basic-combination-args node)))
1569     (vars (lambda-vars (combination-lambda node))))
1570 dtc 1.69 (let ((types (values-types-defaulted (continuation-derived-type arg)
1571     (length vars))))
1572     (mapc #'(lambda (var type)
1573     (if (basic-var-sets var)
1574     (propagate-from-sets var type)
1575     (propagate-to-refs var type)))
1576     vars types))
1577 ram 1.6
1578     (setf (continuation-reoptimize arg) nil))
1579 wlott 1.1 (undefined-value))
1580 ram 1.19
1581    
1582 ram 1.21 ;;; IR1-OPTIMIZE-MV-CALL -- Internal
1583 ram 1.19 ;;;
1584 ram 1.21 ;;; If possible, convert a general MV call to an MV-BIND. We can do this
1585     ;;; if:
1586 ram 1.22 ;;; -- The call has only one argument, and
1587 ram 1.21 ;;; -- The function has a known fixed number of arguments, or
1588 ram 1.22 ;;; -- The argument yields a known fixed number of values.
1589 ram 1.21 ;;;
1590     ;;; What we do is change the function in the MV-CALL to be a lambda that "looks
1591     ;;; like an MV bind", which allows IR1-OPTIMIZE-MV-COMBINATION to notice that
1592     ;;; this call can be converted (the next time around.) This new lambda just
1593 ram 1.31 ;;; calls the actual function with the MV-BIND variables as arguments. Note
1594     ;;; that this new MV bind is not let-converted immediately, as there are going
1595     ;;; to be stray references from the entry-point functions until they get
1596     ;;; deleted.
1597 ram 1.21 ;;;
1598     ;;; In order to avoid loss of argument count checking, we only do the
1599     ;;; transformation according to a known number of expected argument if safety
1600     ;;; is unimportant. We can always convert if we know the number of actual
1601     ;;; values, since the normal call that we build will still do any appropriate
1602     ;;; argument count checking.
1603     ;;;
1604     ;;; We only attempt the transformation if the called function is a constant
1605     ;;; reference. This allows us to just splice the leaf into the new function,
1606     ;;; instead of trying to somehow bind the function expression. The leaf must
1607     ;;; be constant because we are evaluating it again in a different place. This
1608     ;;; also has the effect of squelching multiple warnings when there is an
1609     ;;; argument count error.
1610     ;;;
1611     (defun ir1-optimize-mv-call (node)
1612     (let ((fun (basic-combination-fun node))
1613     (*compiler-error-context* node)
1614 ram 1.22 (ref (continuation-use (basic-combination-fun node)))
1615     (args (basic-combination-args node)))
1616 ram 1.21
1617 ram 1.22 (unless (and (ref-p ref) (constant-reference-p ref)
1618     args (null (rest args)))
1619 ram 1.21 (return-from ir1-optimize-mv-call))
1620    
1621     (multiple-value-bind (min max)
1622     (function-type-nargs (continuation-type fun))
1623 ram 1.22 (let ((total-nvals
1624     (multiple-value-bind
1625     (types nvals)
1626     (values-types (continuation-derived-type (first args)))
1627     (declare (ignore types))
1628     (if (eq nvals :unknown) nil nvals))))
1629 ram 1.21
1630 ram 1.22 (when total-nvals
1631     (when (and min (< total-nvals min))
1632     (compiler-warning
1633     "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1634     at least ~R."
1635     total-nvals min)
1636 ram 1.50 (setf (basic-combination-kind node) :error)
1637 ram 1.22 (return-from ir1-optimize-mv-call))
1638     (when (and max (> total-nvals max))
1639     (compiler-warning
1640     "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1641     at most ~R."
1642     total-nvals max)
1643 ram 1.50 (setf (basic-combination-kind node) :error)
1644 ram 1.22 (return-from ir1-optimize-mv-call)))
1645 ram 1.21
1646 ram 1.22 (let ((count (cond (total-nvals)
1647     ((and (policy node (zerop safety)) (eql min max))
1648     min)
1649     (t nil))))
1650     (when count
1651     (with-ir1-environment node
1652     (let* ((dums (loop repeat count collect (gensym)))
1653     (ignore (gensym))
1654     (fun (ir1-convert-lambda
1655     `(lambda (&optional ,@dums &rest ,ignore)
1656     (declare (ignore ,ignore))
1657     (funcall ,(ref-leaf ref) ,@dums)))))
1658     (change-ref-leaf ref fun)
1659     (assert (eq (basic-combination-kind node) :full))
1660     (local-call-analyze *current-component*)
1661 ram 1.23 (assert (eq (basic-combination-kind node) :local)))))))))
1662 ram 1.21 (undefined-value))
1663    
1664    
1665     ;;; CONVERT-MV-BIND-TO-LET -- Internal
1666     ;;;
1667 ram 1.19 ;;; If we see:
1668     ;;; (multiple-value-bind (x y)
1669     ;;; (values xx yy)
1670     ;;; ...)
1671     ;;; Convert to:
1672     ;;; (let ((x xx)
1673     ;;; (y yy))
1674     ;;; ...)
1675     ;;;
1676     ;;; What we actually do is convert the VALUES combination into a normal let
1677 ram 1.31 ;;; combination calling the original :MV-LET lambda. If there are extra args to
1678 ram 1.19 ;;; VALUES, discard the corresponding continuations. If there are insufficient
1679     ;;; args, insert references to NIL.
1680     ;;;
1681 ram 1.21 (defun convert-mv-bind-to-let (call)
1682     (declare (type mv-combination call))
1683     (let* ((arg (first (basic-combination-args call)))
1684     (use (continuation-use arg)))
1685     (when (and (combination-p use)
1686     (eq (continuation-function-name (combination-fun use))
1687     'values))
1688     (let* ((fun (combination-lambda call))
1689 ram 1.19 (vars (lambda-vars fun))
1690 ram 1.21 (vals (combination-args use))
1691 ram 1.19 (nvars (length vars))
1692     (nvals (length vals)))
1693     (cond ((> nvals nvars)
1694     (mapc #'flush-dest (subseq vals nvars))
1695     (setq vals (subseq vals 0 nvars)))
1696     ((< nvals nvars)
1697 ram 1.21 (with-ir1-environment use
1698     (let ((node-prev (node-prev use)))
1699     (setf (node-prev use) nil)
1700 ram 1.19 (setf (continuation-next node-prev) nil)
1701     (collect ((res vals))
1702 ram 1.21 (loop as cont = (make-continuation use)
1703 ram 1.19 and prev = node-prev then cont
1704     repeat (- nvars nvals)
1705     do (reference-constant prev cont nil)
1706     (res cont))
1707     (setq vals (res)))
1708 ram 1.21 (prev-link use (car (last vals)))))))
1709     (setf (combination-args use) vals)
1710     (flush-dest (combination-fun use))
1711     (let ((fun-cont (basic-combination-fun call)))
1712     (setf (continuation-dest fun-cont) use)
1713     (setf (combination-fun use) fun-cont))
1714     (setf (combination-kind use) :local)
1715 ram 1.19 (setf (functional-kind fun) :let)
1716 ram 1.21 (flush-dest (first (basic-combination-args call)))
1717     (unlink-node call)
1718 ram 1.19 (when vals
1719 ram 1.20 (reoptimize-continuation (first vals)))
1720 ram 1.21 (propagate-to-args use fun))
1721     t)))
1722    
1723    
1724     ;;; VALUES-LIST IR1 optimizer -- Internal
1725     ;;;
1726     ;;; If we see:
1727     ;;; (values-list (list x y z))
1728     ;;;
1729     ;;; Convert to:
1730     ;;; (values x y z)
1731     ;;;
1732     ;;; In implementation, this is somewhat similar to CONVERT-MV-BIND-TO-LET. We
1733     ;;; grab the args of LIST and make them args of the VALUES-LIST call, flushing
1734     ;;; the old argument continuation (allowing the LIST to be flushed.)
1735     ;;;
1736     (defoptimizer (values-list optimizer) ((list) node)
1737     (let ((use (continuation-use list)))
1738     (when (and (combination-p use)
1739     (eq (continuation-function-name (combination-fun use))
1740     'list))
1741     (change-ref-leaf (continuation-use (combination-fun node))
1742     (find-free-function 'values "in a strange place"))
1743     (setf (combination-kind node) :full)
1744     (let ((args (combination-args use)))
1745     (dolist (arg args)
1746     (setf (continuation-dest arg) node))
1747     (setf (combination-args use) nil)
1748     (flush-dest list)
1749     (setf (combination-args node) args))
1750 ram 1.19 t)))
1751    
1752    
1753     ;;; VALUES IR1 transform -- Internal
1754     ;;;
1755     ;;; If VALUES appears in a non-MV context, then effectively convert it to a
1756     ;;; PROG1. This allows the computation of the additional values to become dead
1757 dtc 1.68 ;;; code. Some attempt is made to correct the node derived type, setting it to
1758     ;;; the received single-value-type. The node continuation asserted type must
1759     ;;; also be adjusted, taking care when the continuation has multiple uses.
1760 ram 1.19 ;;;
1761     (deftransform values ((&rest vals) * * :node node)
1762 dtc 1.68 (let ((cont (node-cont node)))
1763     (when (typep (continuation-dest cont) '(or creturn exit mv-combination))
1764     (give-up))
1765     (flet ((first-value-type (type)
1766     (declare (type ctype type))
1767     (cond ((values-type-p type)
1768     (let ((required (args-type-required type)))
1769     (if required
1770     (first required)
1771     (let ((otype (args-type-optional type)))
1772     (cond (otype (first otype))
1773     ((or (args-type-keyp type)
1774     (args-type-allowp type))
1775     *universal-type*)
1776     ((args-type-rest type))
1777     (t *null-type*))))))
1778     ((eq type *wild-type*)
1779     *universal-type*)
1780     (t
1781     type))))
1782     (cond ((= (length (find-uses cont)) 1)
1783     (setf (node-derived-type node)
1784     (single-value-type (node-derived-type node)))
1785     (setf (continuation-asserted-type cont)
1786     (first-value-type (continuation-asserted-type cont))))
1787     (t
1788     (setf (node-derived-type node)
1789     (single-value-type (node-derived-type node)))
1790     (setf (continuation-asserted-type cont)
1791     (values-type-union (continuation-asserted-type cont)
1792     (first-value-type
1793     (continuation-asserted-type cont)))))))
1794     (reoptimize-continuation cont)
1795     (if vals
1796     (let ((dummies (loop repeat (1- (length vals))
1797     collect (gensym))))
1798     `(lambda (val ,@dummies)
1799     (declare (ignore ,@dummies))
1800     val))
1801     'nil)))

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