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Revision 1.84 - (hide annotations)
Wed Oct 19 13:44:01 2005 UTC (8 years, 6 months ago) by rtoy
Branch: MAIN
CVS Tags: snapshot-2005-11
Changes since 1.83: +23 -1 lines
Port SBCL'S support for detecting when destructive functions (such as
nreverse) modify constant args and for warning when the result of
destructive functions is not used.

Detecting modification of constant args is done by adding a new IR1
transformation that checks that a function is not destructively
modifying constants or literals.

A new IR1 attribute, important-result, is used to determine if the
result of a function should be used instead of discarded.  (Note:
this means some functions are not detected.  This should probably be
implemented as another transform so the compiler can detect those cases.)

code/error.lisp:
o Add new condition CONSTANT-MODIFIED.

compiler/fndb.lisp:
o Note destructive functions that should not modify constant args
o Note destructive functions whose results should be used.

compiler/ir1opt.lisp:
o Add new function CHECK-IMPORTANT-RESULT to check if the result is
  used.
o Update IR1-OPTIMIZE-COMBINATION to check if a function destructively
  modifies constant args or if the result of a destructive function is
  not used.

compiler/knownfun.lisp:
o Add new IR1 attribute, IMPORTANT-RESULT, to indicate that the result
  of a function should be used.
o Add new FUNCTION-INFO slot, DESTROYED-CONSTANT-ARGS.  This holds a
  function for computing the constant or literal arguments which are
  destructively modified by the function.
o Add support functions for DESTROYED-CONSTANT-ARGS functions.
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 rtoy 1.84 "$Header: /tiger/var/lib/cvsroots/cmucl/src/compiler/ir1opt.lisp,v 1.84 2005/10/19 13:44:01 rtoy 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 gerd 1.80 (node-derived-type (continuation-use cont)))
71     (:unused
72     *empty-type*)))
73 wlott 1.1
74    
75     ;;; Continuation-Derived-Type -- Interface
76     ;;;
77     ;;; Our best guess for the type of this continuation's value. Note that
78     ;;; this may be Values or Function type, which cannot be passed as an argument
79     ;;; to the normal type operations. See Continuation-Type. This may be called
80     ;;; on deleted continuations, always returning *.
81     ;;;
82     ;;; What we do is call CONTINUATION-PROVEN-TYPE and check whether the result
83     ;;; is a subtype of the assertion. If so, return the proven type and set
84     ;;; TYPE-CHECK to nil. Otherwise, return the intersection of the asserted and
85     ;;; proven types, and set TYPE-CHECK T. If TYPE-CHECK already has a non-null
86     ;;; value, then preserve it. Only in the somewhat unusual circumstance of
87     ;;; a newly discovered assertion will we change TYPE-CHECK from NIL to T.
88     ;;;
89     ;;; The result value is cached in the Continuation-%Derived-Type. If the
90     ;;; slot is true, just return that value, otherwise recompute and stash the
91     ;;; value there.
92     ;;;
93 pw 1.74 (declaim (inline continuation-derived-type))
94 wlott 1.1 (defun continuation-derived-type (cont)
95     (declare (type continuation cont))
96     (or (continuation-%derived-type cont)
97     (%continuation-derived-type cont)))
98     ;;;
99     (defun %continuation-derived-type (cont)
100     (declare (type continuation cont))
101     (let ((proven (continuation-proven-type cont))
102     (asserted (continuation-asserted-type cont)))
103     (cond ((values-subtypep proven asserted)
104     (setf (continuation-%type-check cont) nil)
105     (setf (continuation-%derived-type cont) proven))
106     (t
107     (unless (or (continuation-%type-check cont)
108     (not (continuation-dest cont))
109     (eq asserted *universal-type*))
110     (setf (continuation-%type-check cont) t))
111    
112     (setf (continuation-%derived-type cont)
113     (values-type-intersection asserted proven))))))
114    
115    
116     ;;; CONTINUATION-TYPE-CHECK -- Interface
117     ;;;
118     ;;; Call CONTINUATION-DERIVED-TYPE to make sure the slot is up to date, then
119     ;;; return it.
120     ;;;
121 pw 1.74 (declaim (inline continuation-type-check))
122 wlott 1.1 (defun continuation-type-check (cont)
123     (declare (type continuation cont))
124     (continuation-derived-type cont)
125     (continuation-%type-check cont))
126    
127    
128     ;;; Continuation-Type -- Interface
129     ;;;
130     ;;; Return the derived type for Cont's first value. This is guaranteed not
131     ;;; to be a Values or Function type.
132     ;;;
133     (defun continuation-type (cont)
134 dtc 1.71 (declare (type continuation cont) (values ctype))
135 wlott 1.1 (single-value-type (continuation-derived-type cont)))
136    
137    
138     ;;;; Interface routines used by optimizers:
139    
140     ;;; Reoptimize-Continuation -- Interface
141     ;;;
142     ;;; This function is called by optimizers to indicate that something
143     ;;; interesting has happened to the value of Cont. Optimizers must make sure
144     ;;; that they don't call for reoptimization when nothing has happened, since
145     ;;; optimization will fail to terminate.
146     ;;;
147     ;;; We clear any cached type for the continuation and set the reoptimize
148     ;;; flags on everything in sight, unless the continuation is deleted (in which
149     ;;; case we do nothing.)
150     ;;;
151     ;;; Since this can get called curing IR1 conversion, we have to be careful
152     ;;; not to fly into space when the Dest's Prev is missing.
153     ;;;
154     (defun reoptimize-continuation (cont)
155     (declare (type continuation cont))
156 ram 1.29 (unless (member (continuation-kind cont) '(:deleted :unused))
157 wlott 1.1 (setf (continuation-%derived-type cont) nil)
158     (let ((dest (continuation-dest cont)))
159     (when dest
160     (setf (continuation-reoptimize cont) t)
161     (setf (node-reoptimize dest) t)
162     (let ((prev (node-prev dest)))
163     (when prev
164     (let* ((block (continuation-block prev))
165     (component (block-component block)))
166 ram 1.18 (when (typep dest 'cif)
167     (setf (block-test-modified block) t))
168 wlott 1.1 (setf (block-reoptimize block) t)
169     (setf (component-reoptimize component) t))))))
170     (do-uses (node cont)
171     (setf (block-type-check (node-block node)) t)))
172     (undefined-value))
173    
174    
175     ;;; Derive-Node-Type -- Interface
176     ;;;
177     ;;; Annotate Node to indicate that its result has been proven to be typep to
178     ;;; RType. After IR1 conversion has happened, this is the only correct way to
179     ;;; supply information discovered about a node's type. If you fuck with the
180     ;;; Node-Derived-Type directly, then information may be lost and reoptimization
181     ;;; may not happen.
182     ;;;
183     ;;; What we do is intersect Rtype with Node's Derived-Type. If the
184     ;;; intersection is different from the old type, then we do a
185     ;;; Reoptimize-Continuation on the Node-Cont.
186     ;;;
187     (defun derive-node-type (node rtype)
188     (declare (type node node) (type ctype rtype))
189     (let ((node-type (node-derived-type node)))
190     (unless (eq node-type rtype)
191     (let ((int (values-type-intersection node-type rtype)))
192     (when (type/= node-type int)
193 ram 1.38 (when (and *check-consistency*
194     (eq int *empty-type*)
195 ram 1.34 (not (eq rtype *empty-type*)))
196     (let ((*compiler-error-context* node))
197     (compiler-warning
198     "New inferred type ~S conflicts with old type:~
199     ~% ~S~%*** Bug?"
200     (type-specifier rtype) (type-specifier node-type))))
201 wlott 1.1 (setf (node-derived-type node) int)
202     (reoptimize-continuation (node-cont node))))))
203     (undefined-value))
204    
205 dtc 1.70 (declaim (start-block assert-continuation-type
206     assert-continuation-optional-type assert-call-type))
207 wlott 1.1
208     ;;; Assert-Continuation-Type -- Interface
209     ;;;
210     ;;; Similar to Derive-Node-Type, but asserts that it is an error for Cont's
211     ;;; value not to be typep to Type. If we improve the assertion, we set
212 ram 1.11 ;;; TYPE-CHECK and TYPE-ASSERTED to guarantee that the new assertion will be
213     ;;; checked.
214 wlott 1.1 ;;;
215     (defun assert-continuation-type (cont type)
216     (declare (type continuation cont) (type ctype type))
217     (let ((cont-type (continuation-asserted-type cont)))
218     (unless (eq cont-type type)
219     (let ((int (values-type-intersection cont-type type)))
220     (when (type/= cont-type int)
221     (setf (continuation-asserted-type cont) int)
222     (do-uses (node cont)
223 ram 1.11 (setf (block-attributep (block-flags (node-block node))
224     type-check type-asserted)
225     t))
226 wlott 1.1 (reoptimize-continuation cont)))))
227     (undefined-value))
228    
229    
230 dtc 1.70 ;;; Assert-continuation-optional-type -- Interface
231     ;;;
232     ;;; Similar to Assert-Continuation-Type, but asserts that the type is
233     ;;; for an optional argument and that other arguments may be received.
234     ;;;
235     (defun assert-continuation-optional-type (cont type)
236     (declare (type continuation cont) (type ctype type))
237     (let ((opt-type (make-values-type :optional (list type)
238     :rest *universal-type*)))
239     (assert-continuation-type cont opt-type)))
240    
241    
242 wlott 1.1 ;;; Assert-Call-Type -- Interface
243     ;;;
244     ;;; Assert that Call is to a function of the specified Type. It is assumed
245     ;;; that the call is legal and has only constants in the keyword positions.
246     ;;;
247     (defun assert-call-type (call type)
248     (declare (type combination call) (type function-type type))
249     (derive-node-type call (function-type-returns type))
250     (let ((args (combination-args call)))
251     (dolist (req (function-type-required type))
252     (when (null args) (return-from assert-call-type))
253     (let ((arg (pop args)))
254 dtc 1.70 (assert-continuation-optional-type arg req)))
255 wlott 1.1 (dolist (opt (function-type-optional type))
256     (when (null args) (return-from assert-call-type))
257     (let ((arg (pop args)))
258 dtc 1.70 (assert-continuation-optional-type arg opt)))
259 wlott 1.1
260     (let ((rest (function-type-rest type)))
261     (when rest
262     (dolist (arg args)
263 dtc 1.70 (assert-continuation-optional-type arg rest))))
264 wlott 1.1
265     (dolist (key (function-type-keywords type))
266     (let ((name (key-info-name key)))
267     (do ((arg args (cddr arg)))
268     ((null arg))
269     (when (eq (continuation-value (first arg)) name)
270 dtc 1.70 (assert-continuation-optional-type
271 wlott 1.1 (second arg) (key-info-type key)))))))
272     (undefined-value))
273    
274    
275 ram 1.50 ;;;; IR1-OPTIMIZE:
276    
277     (declaim (start-block ir1-optimize))
278    
279 wlott 1.1 ;;; IR1-Optimize -- Interface
280     ;;;
281     ;;; Do one forward pass over Component, deleting unreachable blocks and
282 ram 1.11 ;;; doing IR1 optimizations. We can ignore all blocks that don't have the
283     ;;; Reoptimize flag set. If Component-Reoptimize is true when we are done,
284 wlott 1.1 ;;; then another iteration would be beneficial.
285     ;;;
286     ;;; We delete blocks when there is either no predecessor or the block is in
287     ;;; a lambda that has been deleted. These blocks would eventually be deleted
288     ;;; by DFO recomputation, but doing it here immediately makes the effect
289     ;;; avaliable to IR1 optimization.
290     ;;;
291     (defun ir1-optimize (component)
292     (declare (type component component))
293     (setf (component-reoptimize component) nil)
294     (do-blocks (block component)
295     (cond
296 gerd 1.82 ((block-unreachable-p block)
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 1.82 (let ((if-test (if-test last)))
308     ;; Don't flush an if-test if it requires a type check.
309     (unless (memq (continuation-type-check if-test) '(nil :deleted))
310     (return))
311     (flush-dest if-test)
312     (when (unlink-node last)
313     (return))))
314 wlott 1.1 (exit
315 gerd 1.82 (when (maybe-delete-exit last)
316     (return)))))
317 wlott 1.1
318     (unless (join-successor-if-possible block)
319     (return)))
320 gerd 1.82 ;;
321     ;; Block-Component is nil for deleted blocks.
322     (when (block-component block)
323     (cond ((block-unreachable-p block)
324     (delete-block block))
325     (t
326     (when (block-reoptimize block)
327     (ir1-optimize-block block))
328     (when (and (block-flush-p block)
329     (block-component block))
330     (flush-dead-code block))))))))
331     (values))
332 wlott 1.1
333     ;;; IR1-Optimize-Block -- Internal
334     ;;;
335     ;;; Loop over the nodes in Block, looking for stuff that needs to be
336     ;;; optimized. We dispatch off of the type of each node with its reoptimize
337     ;;; flag set:
338     ;;; -- With a combination, we call Propagate-Function-Change whenever the
339     ;;; function changes, and call IR1-Optimize-Combination if any argument
340     ;;; changes.
341     ;;; -- With an Exit, we derive the node's type from the Value's type. We don't
342     ;;; propagate Cont's assertion to the Value, since if we did, this would
343     ;;; move the checking of Cont's assertion to the exit. This wouldn't work
344     ;;; with Catch and UWP, where the Exit node is just a placeholder for the
345     ;;; actual unknown exit.
346     ;;;
347     ;;; Note that we clear the node & block reoptimize flags *before* doing the
348     ;;; optimization. This ensures that the node or block will be reoptimized if
349 ram 1.19 ;;; necessary. We leave the NODE-OPTIMIZE flag set going into
350 wlott 1.1 ;;; IR1-OPTIMIZE-RETURN, since it wants to clear the flag itself.
351     ;;;
352     (defun ir1-optimize-block (block)
353     (declare (type cblock block))
354     (setf (block-reoptimize block) nil)
355 ram 1.19 (do-nodes (node cont block :restart-p t)
356 wlott 1.1 (when (node-reoptimize node)
357     (setf (node-reoptimize node) nil)
358     (typecase node
359     (ref)
360     (combination
361 ram 1.50 (ir1-optimize-combination node))
362 wlott 1.1 (cif
363     (ir1-optimize-if node))
364     (creturn
365     (setf (node-reoptimize node) t)
366     (ir1-optimize-return node))
367 ram 1.6 (mv-combination
368 ram 1.21 (ir1-optimize-mv-combination node))
369 wlott 1.1 (exit
370     (let ((value (exit-value node)))
371     (when value
372     (derive-node-type node (continuation-derived-type value)))))
373     (cset
374     (ir1-optimize-set node)))))
375     (undefined-value))
376    
377 ram 1.50
378 wlott 1.1 ;;; Join-Successor-If-Possible -- Internal
379     ;;;
380     ;;; We cannot combine with a successor block if:
381     ;;; 1] The successor has more than one predecessor.
382     ;;; 2] The last node's Cont is also used somewhere else.
383     ;;; 3] The successor is the current block (infinite loop).
384     ;;; 4] The next block has a different cleanup, and thus we may want to insert
385     ;;; cleanup code between the two blocks at some point.
386     ;;; 5] The next block has a different home lambda, and thus the control
387     ;;; transfer is a non-local exit.
388     ;;;
389     ;;; If we succeed, we return true, otherwise false.
390     ;;;
391     ;;; Joining is easy when the successor's Start continuation is the same from
392     ;;; our Last's Cont. If they differ, then we can still join when the last
393     ;;; continuation has no next and the next continuation has no uses. In this
394 ram 1.5 ;;; case, we replace the next continuation with the last before joining the
395 wlott 1.1 ;;; blocks.
396     ;;;
397     (defun join-successor-if-possible (block)
398     (declare (type cblock block))
399     (let ((next (first (block-succ block))))
400 ram 1.11 (when (block-start next)
401 wlott 1.1 (let* ((last (block-last block))
402     (last-cont (node-cont last))
403 ram 1.11 (next-cont (block-start next)))
404 wlott 1.1 (cond ((or (rest (block-pred next))
405 ram 1.5 (not (eq (continuation-use last-cont) last))
406 wlott 1.1 (eq next block)
407 ram 1.11 (not (eq (block-end-cleanup block)
408     (block-start-cleanup next)))
409     (not (eq (block-home-lambda block)
410     (block-home-lambda next))))
411 wlott 1.1 nil)
412 ram 1.5 ((eq last-cont next-cont)
413 wlott 1.1 (join-blocks block next)
414     t)
415 ram 1.5 ((and (null (block-start-uses next))
416     (eq (continuation-kind last-cont) :inside-block))
417     (let ((next-node (continuation-next next-cont)))
418 ram 1.30 ;;
419     ;; If next-cont does have a dest, it must be unreachable,
420     ;; since there are no uses. DELETE-CONTINUATION will mark the
421     ;; dest block as delete-p [and also this block, unless it is
422     ;; no longer backward reachable from the dest block.]
423 ram 1.5 (delete-continuation next-cont)
424     (setf (node-prev next-node) last-cont)
425     (setf (continuation-next last-cont) next-node)
426     (setf (block-start next) last-cont)
427     (join-blocks block next))
428 wlott 1.1 t)
429     (t
430     nil))))))
431    
432    
433     ;;; Join-Blocks -- Internal
434     ;;;
435     ;;; Join together two blocks which have the same ending/starting
436     ;;; continuation. The code in Block2 is moved into Block1 and Block2 is
437 ram 1.11 ;;; deleted from the DFO. We combine the optimize flags for the two blocks so
438     ;;; that any indicated optimization gets done.
439 wlott 1.1 ;;;
440     (defun join-blocks (block1 block2)
441     (declare (type cblock block1 block2))
442     (let* ((last (block-last block2))
443     (last-cont (node-cont last))
444     (succ (block-succ block2))
445     (start2 (block-start block2)))
446     (do ((cont start2 (node-cont (continuation-next cont))))
447     ((eq cont last-cont)
448     (when (eq (continuation-kind last-cont) :inside-block)
449     (setf (continuation-block last-cont) block1)))
450     (setf (continuation-block cont) block1))
451    
452     (unlink-blocks block1 block2)
453     (dolist (block succ)
454     (unlink-blocks block2 block)
455     (link-blocks block1 block))
456    
457     (setf (block-last block1) last)
458     (setf (continuation-kind start2) :inside-block))
459    
460 ram 1.11 (setf (block-flags block1)
461     (attributes-union (block-flags block1)
462     (block-flags block2)
463     (block-attributes type-asserted test-modified)))
464 wlott 1.1
465     (let ((next (block-next block2))
466     (prev (block-prev block2)))
467     (setf (block-next prev) next)
468     (setf (block-prev next) prev))
469    
470     (undefined-value))
471    
472 ram 1.50 ;;; Flush-Dead-Code -- Internal
473     ;;;
474     ;;; Delete any nodes in Block whose value is unused and have no
475     ;;; side-effects. We can delete sets of lexical variables when the set
476     ;;; variable has no references.
477     ;;;
478     ;;; [### For now, don't delete potentially flushable calls when they have the
479     ;;; Call attribute. Someday we should look at the funcitonal args to determine
480     ;;; if they have any side-effects.]
481     ;;;
482     (defun flush-dead-code (block)
483     (declare (type cblock block))
484     (do-nodes-backwards (node cont block)
485     (unless (continuation-dest cont)
486     (typecase node
487     (ref
488     (delete-ref node)
489     (unlink-node node))
490     (combination
491     (let ((info (combination-kind node)))
492     (when (function-info-p info)
493     (let ((attr (function-info-attributes info)))
494     (when (and (ir1-attributep attr flushable)
495     (not (ir1-attributep attr call)))
496 gerd 1.76 (if (policy node (= safety 3))
497     ;; Don't flush calls to flushable functions if
498     ;; their value is unused in safe code, because
499     ;; this means something like (PROGN (FBOUNDP 42)
500     ;; T) won't signal an error. KLUDGE: The right
501     ;; thing to do here is probably teaching
502     ;; MAYBE-NEGATE-CHECK and friends to accept nil
503     ;; continuation-dests instead of faking one.
504     ;; Can't be bothered at present.
505     ;; Gerd, 2003-04-26.
506     (setf (continuation-dest cont)
507     (continuation-next cont))
508     (progn
509     (flush-dest (combination-fun node))
510     (dolist (arg (combination-args node))
511     (flush-dest arg))
512     (unlink-node node))))))))
513 ram 1.50 (mv-combination
514     (when (eq (basic-combination-kind node) :local)
515     (let ((fun (combination-lambda node)))
516     (when (dolist (var (lambda-vars fun) t)
517     (when (or (leaf-refs var)
518     (lambda-var-sets var))
519     (return nil)))
520     (flush-dest (first (basic-combination-args node)))
521     (delete-let fun)))))
522     (exit
523     (let ((value (exit-value node)))
524     (when value
525     (flush-dest value)
526     (setf (exit-value node) nil))))
527     (cset
528     (let ((var (set-var node)))
529     (when (and (lambda-var-p var)
530     (null (leaf-refs var)))
531     (flush-dest (set-value node))
532     (setf (basic-var-sets var)
533     (delete node (basic-var-sets var)))
534     (unlink-node node)))))))
535    
536     (setf (block-flush-p block) nil)
537     (undefined-value))
538    
539     (declaim (end-block))
540    
541 wlott 1.1
542     ;;;; Local call return type propagation:
543    
544     ;;; Find-Result-Type -- Internal
545     ;;;
546     ;;; This function is called on RETURN nodes that have their REOPTIMIZE flag
547     ;;; set. It iterates over the uses of the RESULT, looking for interesting
548 ram 1.46 ;;; stuff to update the TAIL-SET. If a use isn't a local call, then we union
549     ;;; its type together with the types of other such uses. We assign to the
550     ;;; RETURN-RESULT-TYPE the intersection of this type with the RESULT's asserted
551     ;;; type. We can make this intersection now (potentially before type checking)
552     ;;; because this assertion on the result will eventually be checked (if
553     ;;; appropriate.)
554 wlott 1.1 ;;;
555 ram 1.46 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV combination,
556     ;;; which may change the succesor of the call to be the called function, and if
557 ram 1.56 ;;; so, checks if the call can become an assignment. If we convert to an
558     ;;; assignment, we abort, since the RETURN has been deleted.
559 ram 1.46 ;;;
560     (defun find-result-type (node)
561 wlott 1.1 (declare (type creturn node))
562 ram 1.46 (let ((result (return-result node)))
563 wlott 1.1 (collect ((use-union *empty-type* values-type-union))
564     (do-uses (use result)
565 gerd 1.81 (let ((use-home (node-home-lambda use)))
566     (cond ((or (eq (functional-kind use-home) :deleted)
567     (block-delete-p (node-block use))))
568     ((and (basic-combination-p use)
569     (eq (basic-combination-kind use) :local))
570     (assert (eq (lambda-tail-set use-home)
571     (lambda-tail-set (combination-lambda use))))
572     (when (combination-p use)
573     (when (nth-value 1 (maybe-convert-tail-local-call use))
574     (return-from find-result-type (values)))))
575     (t
576     (use-union (node-derived-type use))))))
577 dtc 1.70 (let ((int (values-type-intersection (continuation-asserted-type result)
578     (use-union))))
579 ram 1.46 (setf (return-result-type node) int))))
580 gerd 1.81 (values))
581 wlott 1.1
582    
583     ;;; IR1-Optimize-Return -- Internal
584     ;;;
585     ;;; Do stuff to realize that something has changed about the value delivered
586     ;;; to a return node. Since we consider the return values of all functions in
587     ;;; the tail set to be equivalent, this amounts to bringing the entire tail set
588     ;;; up to date. We iterate over the returns for all the functions in the tail
589     ;;; set, reanalyzing them all (not treating Node specially.)
590     ;;;
591     ;;; When we are done, we check if the new type is different from the old
592     ;;; TAIL-SET-TYPE. If so, we set the type and also reoptimize all the
593     ;;; continuations for references to functions in the tail set. This will
594     ;;; cause IR1-OPTIMIZE-COMBINATION to derive the new type as the results of the
595     ;;; calls.
596     ;;;
597     (defun ir1-optimize-return (node)
598     (declare (type creturn node))
599 ram 1.46 (let* ((tails (lambda-tail-set (return-lambda node)))
600     (funs (tail-set-functions tails)))
601 wlott 1.1 (collect ((res *empty-type* values-type-union))
602 ram 1.46 (dolist (fun funs)
603     (let ((return (lambda-return fun)))
604     (when return
605     (when (node-reoptimize return)
606 ram 1.58 (setf (node-reoptimize return) nil)
607 ram 1.46 (find-result-type return))
608     (res (return-result-type return)))))
609 wlott 1.1
610     (when (type/= (res) (tail-set-type tails))
611     (setf (tail-set-type tails) (res))
612     (dolist (fun (tail-set-functions tails))
613     (dolist (ref (leaf-refs fun))
614     (reoptimize-continuation (node-cont ref)))))))
615    
616     (undefined-value))
617    
618    
619 ram 1.50 ;;; IF optimization:
620    
621     (declaim (start-block ir1-optimize-if))
622    
623 wlott 1.1 ;;; IR1-Optimize-If -- Internal
624     ;;;
625     ;;; If the test has multiple uses, replicate the node when possible. Also
626     ;;; check if the predicate is known to be true or false, deleting the IF node
627     ;;; in favor of the appropriate branch when this is the case.
628     ;;;
629     (defun ir1-optimize-if (node)
630     (declare (type cif node))
631     (let ((test (if-test node))
632     (block (node-block node)))
633    
634     (when (and (eq (block-start block) test)
635     (eq (continuation-next test) node)
636     (rest (block-start-uses block)))
637     (do-uses (use test)
638     (when (immediately-used-p test use)
639     (convert-if-if use node)
640     (when (continuation-use test) (return)))))
641 gerd 1.77 ;;
642     ;; Don't flush if-tests when they require a type check.
643     (when (memq (continuation-type-check test) '(nil :deleted))
644     (let* ((type (continuation-type test))
645     (victim
646     (cond ((constant-continuation-p test)
647     (if (continuation-value test)
648     (if-alternative node)
649     (if-consequent node)))
650     ((not (types-intersect type *null-type*))
651     (if-alternative node))
652     ((type= type *null-type*)
653     (if-consequent node)))))
654     (when victim
655     (flush-dest test)
656     (when (rest (block-succ block))
657     (unlink-blocks block victim))
658     (setf (component-reanalyze (block-component (node-block node))) t)
659     (unlink-node node)))))
660 wlott 1.1 (undefined-value))
661    
662    
663     ;;; Convert-If-If -- Internal
664     ;;;
665     ;;; Create a new copy of an IF Node that tests the value of the node Use.
666     ;;; The test must have >1 use, and must be immediately used by Use. Node must
667     ;;; be the only node in its block (implying that block-start = if-test).
668     ;;;
669     ;;; This optimization has an effect semantically similar to the
670     ;;; source-to-source transformation:
671     ;;; (IF (IF A B C) D E) ==>
672     ;;; (IF A (IF B D E) (IF C D E))
673     ;;;
674 ram 1.55 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new node so
675     ;;; that dead code deletion notes will definitely not consider either node to
676     ;;; be part of the original source. One node might become unreachable,
677     ;;; resulting in a spurious note.
678     ;;;
679 wlott 1.1 (defun convert-if-if (use node)
680     (declare (type node use) (type cif node))
681     (with-ir1-environment node
682     (let* ((block (node-block node))
683     (test (if-test node))
684     (cblock (if-consequent node))
685     (ablock (if-alternative node))
686     (use-block (node-block use))
687     (dummy-cont (make-continuation))
688     (new-cont (make-continuation))
689 ram 1.11 (new-node (make-if :test new-cont
690 wlott 1.1 :consequent cblock :alternative ablock))
691     (new-block (continuation-starts-block new-cont)))
692     (prev-link new-node new-cont)
693     (setf (continuation-dest new-cont) new-node)
694     (add-continuation-use new-node dummy-cont)
695     (setf (block-last new-block) new-node)
696    
697     (unlink-blocks use-block block)
698     (delete-continuation-use use)
699     (add-continuation-use use new-cont)
700     (link-blocks use-block new-block)
701    
702     (link-blocks new-block cblock)
703     (link-blocks new-block ablock)
704 ram 1.55
705     (push "<IF Duplication>" (node-source-path node))
706     (push "<IF Duplication>" (node-source-path new-node))
707 wlott 1.1
708     (reoptimize-continuation test)
709     (reoptimize-continuation new-cont)
710     (setf (component-reanalyze *current-component*) t)))
711     (undefined-value))
712    
713 ram 1.50 (declaim (end-block))
714    
715 wlott 1.1
716     ;;;; Exit IR1 optimization:
717    
718     ;;; Maybe-Delete-Exit -- Interface
719     ;;;
720     ;;; This function attempts to delete an exit node, returning true if it
721     ;;; deletes the block as a consequence:
722     ;;; -- If the exit is degenerate (has no Entry), then we don't do anything,
723     ;;; since there is nothing to be done.
724     ;;; -- If the exit node and its Entry have the same home lambda then we know
725     ;;; the exit is local, and can delete the exit. We change uses of the
726     ;;; Exit-Value to be uses of the original continuation, then unlink the
727 ram 1.46 ;;; node. If the exit is to a TR context, then we must do MERGE-TAIL-SETS
728     ;;; on any local calls which delivered their value to this exit.
729 wlott 1.1 ;;; -- If there is no value (as in a GO), then we skip the value semantics.
730     ;;;
731     ;;; This function is also called by environment analysis, since it wants all
732     ;;; exits to be optimized even if normal optimization was omitted.
733     ;;;
734     (defun maybe-delete-exit (node)
735     (declare (type exit node))
736     (let ((value (exit-value node))
737     (entry (exit-entry node))
738     (cont (node-cont node)))
739     (when (and entry
740 ram 1.11 (eq (node-home-lambda node) (node-home-lambda entry)))
741     (setf (entry-exits entry) (delete node (entry-exits entry)))
742 wlott 1.1 (prog1
743     (unlink-node node)
744     (when value
745 ram 1.46 (collect ((merges))
746     (when (return-p (continuation-dest cont))
747     (do-uses (use value)
748     (when (and (basic-combination-p use)
749     (eq (basic-combination-kind use) :local))
750     (merges use))))
751 gerd 1.79 (when (null (continuation-dest cont))
752     (flush-dest value))
753 ram 1.46 (substitute-continuation-uses cont value)
754     (dolist (merge (merges))
755     (merge-tail-sets merge))))))))
756 wlott 1.1
757 rtoy 1.84 (defun check-important-result (node kind)
758     (let ((attr (function-info-attributes kind)))
759     (when (and attr
760     (ir1-attributep attr important-result)
761     (null (continuation-dest (node-cont node))))
762     (let ((*compiler-error-context* node))
763     (compiler-warning "The return value of ~A should not be discarded."
764     (continuation-function-name (basic-combination-fun node)))))))
765    
766 wlott 1.1
767     ;;;; Combination IR1 optimization:
768    
769 ram 1.50 (declaim (start-block ir1-optimize-combination maybe-terminate-block
770     validate-call-type))
771    
772 wlott 1.1 ;;; Ir1-Optimize-Combination -- Internal
773     ;;;
774     ;;; Do IR1 optimizations on a Combination node.
775     ;;;
776     (defun ir1-optimize-combination (node)
777 dtc 1.71 (declare (type combination node))
778 ram 1.50 (when (continuation-reoptimize (basic-combination-fun node))
779     (propagate-function-change node))
780 wlott 1.1 (let ((args (basic-combination-args node))
781     (kind (basic-combination-kind node)))
782     (case kind
783     (:local
784     (let ((fun (combination-lambda node)))
785     (if (eq (functional-kind fun) :let)
786     (propagate-let-args node fun)
787     (propagate-local-call-args node fun))))
788 ram 1.50 ((:full :error)
789 wlott 1.1 (dolist (arg args)
790     (when arg
791     (setf (continuation-reoptimize arg) nil))))
792     (t
793     (dolist (arg args)
794     (when arg
795     (setf (continuation-reoptimize arg) nil)))
796    
797 rtoy 1.84 (check-important-result node kind)
798    
799     (let ((fun (function-info-destroyed-constant-args kind)))
800     (when fun
801     (let ((destroyed-constant-args (funcall fun args)))
802     (when destroyed-constant-args
803     (let ((*compiler-error-context* node))
804     (warn 'kernel:constant-modified
805     :function-name (continuation-function-name
806     (basic-combination-fun node)))
807     (setf (basic-combination-kind node) :error)
808     (return-from ir1-optimize-combination))))))
809    
810 wlott 1.1 (let ((attr (function-info-attributes kind)))
811     (when (and (ir1-attributep attr foldable)
812     (not (ir1-attributep attr call))
813     (every #'constant-continuation-p args)
814     (continuation-dest (node-cont node)))
815     (constant-fold-call node)
816     (return-from ir1-optimize-combination)))
817 ram 1.18
818 wlott 1.1 (let ((fun (function-info-derive-type kind)))
819     (when fun
820     (let ((res (funcall fun node)))
821     (when res
822 ram 1.50 (derive-node-type node res)
823     (maybe-terminate-block node nil)))))
824 ram 1.18
825 wlott 1.1 (let ((fun (function-info-optimizer kind)))
826     (unless (and fun (funcall fun node))
827     (dolist (x (function-info-transforms kind))
828 ram 1.28 (unless (ir1-transform node x)
829 wlott 1.2 (return))))))))
830 wlott 1.1
831     (undefined-value))
832    
833    
834 ram 1.29 ;;; MAYBE-TERMINATE-BLOCK -- Interface
835     ;;;
836     ;;; If Call is to a function that doesn't return (type NIL), then terminate
837 ram 1.31 ;;; the block there, and link it to the component tail. We also change the
838     ;;; call's CONT to be a dummy continuation to prevent the use from confusing
839     ;;; things.
840 ram 1.29 ;;;
841 ram 1.30 ;;; Except when called during IR1, we delete the continuation if it has no
842     ;;; other uses. (If it does have other uses, we reoptimize.)
843     ;;;
844 ram 1.31 ;;; Termination on the basis of a continuation type assertion is inhibited
845     ;;; when:
846     ;;; -- The continuation is deleted (hence the assertion is spurious), or
847     ;;; -- We are in IR1 conversion (where THE assertions are subject to
848     ;;; weakening.)
849     ;;;
850 ram 1.30 (defun maybe-terminate-block (call ir1-p)
851 ram 1.29 (declare (type basic-combination call))
852 ram 1.32 (let* ((block (node-block call))
853     (cont (node-cont call))
854     (tail (component-tail (block-component block)))
855     (succ (first (block-succ block))))
856     (unless (or (and (eq call (block-last block)) (eq succ tail))
857 ram 1.50 (block-delete-p block)
858     *converting-for-interpreter*)
859 ram 1.32 (when (or (and (eq (continuation-asserted-type cont) *empty-type*)
860     (not (or ir1-p (eq (continuation-kind cont) :deleted))))
861     (eq (node-derived-type call) *empty-type*))
862     (cond (ir1-p
863     (delete-continuation-use call)
864     (cond
865     ((block-last block)
866     (assert (and (eq (block-last block) call)
867     (eq (continuation-kind cont) :block-start))))
868     (t
869     (setf (block-last block) call)
870     (link-blocks block (continuation-starts-block cont)))))
871 ram 1.30 (t
872 ram 1.32 (node-ends-block call)
873     (delete-continuation-use call)
874     (if (eq (continuation-kind cont) :unused)
875     (delete-continuation cont)
876     (reoptimize-continuation cont))))
877    
878     (unlink-blocks block (first (block-succ block)))
879 ram 1.45 (setf (component-reanalyze (block-component block)) t)
880 ram 1.32 (assert (not (block-succ block)))
881     (link-blocks block tail)
882     (add-continuation-use call (make-continuation))
883     t))))
884 ram 1.30
885 ram 1.29
886 wlott 1.1 ;;; Recognize-Known-Call -- Interface
887     ;;;
888 ram 1.50 ;;; Called both by IR1 conversion and IR1 optimization when they have
889     ;;; verified the type signature for the call, and are wondering if something
890     ;;; should be done to special-case the call. If Call is a call to a global
891     ;;; function, then see if it defined or known:
892     ;;; -- If a DEFINED-FUNCTION should be inline expanded, then convert the
893     ;;; expansion and change the call to call it. Expansion is enabled if
894     ;;; :INLINE or if space=0. If the FUNCTIONAL slot is true, we never expand,
895     ;;; since this function has already been converted. Local call analysis
896     ;;; will duplicate the definition if necessary. We claim that the parent
897     ;;; form is LABELS for context declarations, since we don't want it to be
898     ;;; considered a real global function.
899     ;;; -- In addition to a direct check for the function name in the table, we
900     ;;; also must check for slot accessors. If the function is a slot accessor,
901     ;;; then we set the combination kind to the function info of %Slot-Setter or
902     ;;; %Slot-Accessor, as appropriate.
903     ;;; -- If it is a known function, mark it as such by setting the Kind.
904 wlott 1.1 ;;;
905 ram 1.50 ;;; We return the leaf referenced (NIL if not a leaf) and the function-info
906     ;;; assigned.
907 ram 1.19 ;;;
908 ram 1.50 (defun recognize-known-call (call ir1-p)
909 wlott 1.1 (declare (type combination call))
910 ram 1.50 (let* ((ref (continuation-use (basic-combination-fun call)))
911     (leaf (when (ref-p ref) (ref-leaf ref)))
912 gerd 1.78 (inlinep (if (defined-function-p leaf)
913 ram 1.50 (defined-function-inlinep leaf)
914     :no-chance)))
915 gerd 1.78 (when (and (or (byte-compiling)
916     *converting-for-interpreter*)
917     (member inlinep '(:inline :maybe-inline)))
918     (setq inlinep :notinline))
919 ram 1.50 (cond
920     ((eq inlinep :notinline) (values nil nil))
921     ((not (and (global-var-p leaf)
922     (eq (global-var-kind leaf) :global-function)))
923     (values leaf nil))
924     ((and (ecase inlinep
925     (:inline t)
926     (:no-chance nil)
927     ((nil :maybe-inline) (policy call (zerop space))))
928     (defined-function-inline-expansion leaf)
929     (let ((fun (defined-function-functional leaf)))
930     (or (not fun)
931     (and (eq inlinep :inline) (functional-kind fun))))
932     (inline-expansion-ok call))
933     (flet ((frob ()
934     (let ((res (ir1-convert-lambda-for-defun
935     (defined-function-inline-expansion leaf)
936 ram 1.53 leaf t
937 ram 1.50 #'ir1-convert-inline-lambda
938     'labels)))
939     (setf (defined-function-functional leaf) res)
940     (change-ref-leaf ref res))))
941     (if ir1-p
942     (frob)
943     (with-ir1-environment call
944     (frob)
945     (local-call-analyze *current-component*))))
946 ram 1.53
947 ram 1.50 (values (ref-leaf (continuation-use (basic-combination-fun call)))
948     nil))
949     (t
950     (let* ((name (leaf-name leaf))
951 pw 1.67 (info (info function info
952     (if (slot-accessor-p leaf)
953     (if (consp name)
954     '%slot-setter
955     '%slot-accessor)
956     name))))
957 ram 1.50 (if info
958     (values leaf (setf (basic-combination-kind call) info))
959     (values leaf nil)))))))
960 wlott 1.1
961    
962 ram 1.50 ;;; VALIDATE-CALL-TYPE -- Internal
963     ;;;
964     ;;; Check if Call satisfies Type. If so, apply the type to the call, and do
965     ;;; MAYBE-TERMINATE-BLOCK and return the values of RECOGNIZE-KNOWN-CALL. If an
966 ram 1.57 ;;; error, set the combination kind and return NIL, NIL. If the type is just
967     ;;; FUNCTION, then skip the syntax check, arg/result type processing, but still
968     ;;; call RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda, and
969     ;;; that checking is done by local call analysis.
970 ram 1.50 ;;;
971     (defun validate-call-type (call type ir1-p)
972     (declare (type combination call) (type ctype type))
973 ram 1.57 (cond ((not (function-type-p type))
974     (assert (multiple-value-bind
975     (val win)
976     (csubtypep type (specifier-type 'function))
977     (or val (not win))))
978     (recognize-known-call call ir1-p))
979 ram 1.50 ((valid-function-use call type
980     :argument-test #'always-subtypep
981     :result-test #'always-subtypep
982     :error-function #'compiler-warning
983     :warning-function #'compiler-note)
984     (assert-call-type call type)
985     (maybe-terminate-block call ir1-p)
986     (recognize-known-call call ir1-p))
987     (t
988     (setf (combination-kind call) :error)
989     (values nil nil))))
990    
991    
992 wlott 1.1 ;;; Propagate-Function-Change -- Internal
993     ;;;
994     ;;; Called by Ir1-Optimize when the function for a call has changed.
995 ram 1.50 ;;; If the call is local, we try to let-convert it, and derive the result type.
996     ;;; If it is a :FULL call, we validate it against the type, which recognizes
997     ;;; known calls, does inline expansion, etc. If a call to a predicate in a
998     ;;; non-conditional position or to a function with a source transform, then we
999     ;;; reconvert the form to give IR1 another chance.
1000 wlott 1.1 ;;;
1001     (defun propagate-function-change (call)
1002     (declare (type combination call))
1003 ram 1.50 (let ((*compiler-error-context* call)
1004     (fun-cont (basic-combination-fun call)))
1005     (setf (continuation-reoptimize fun-cont) nil)
1006     (case (combination-kind call)
1007     (:local
1008     (let ((fun (combination-lambda call)))
1009     (maybe-let-convert fun)
1010     (unless (member (functional-kind fun) '(:let :assignment :deleted))
1011     (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
1012     (:full
1013     (multiple-value-bind
1014     (leaf info)
1015 ram 1.59 (validate-call-type call (continuation-type fun-cont) nil)
1016 ram 1.50 (cond ((functional-p leaf)
1017     (convert-call-if-possible
1018     (continuation-use (basic-combination-fun call))
1019     call))
1020     ((not leaf))
1021     ((or (info function source-transform (leaf-name leaf))
1022     (and info
1023     (ir1-attributep (function-info-attributes info)
1024     predicate)
1025     (let ((dest (continuation-dest (node-cont call))))
1026     (and dest (not (if-p dest))))))
1027     (let ((name (leaf-name leaf)))
1028     (when (symbolp name)
1029     (let ((dums (loop repeat (length (combination-args call))
1030     collect (gensym))))
1031     (transform-call call
1032     `(lambda ,dums
1033     (,name ,@dums))))))))))))
1034 wlott 1.1 (undefined-value))
1035    
1036    
1037     ;;;; Known function optimization:
1038    
1039 ram 1.15
1040     ;;; RECORD-OPTIMIZATION-FAILURE -- Internal
1041     ;;;
1042 ram 1.50 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for Node, Fun
1043 ram 1.28 ;;; and Args. If there is already a note for Node and Transform, replace it,
1044 ram 1.15 ;;; otherwise add a new one.
1045     ;;;
1046 ram 1.28 (defun record-optimization-failure (node transform args)
1047     (declare (type combination node) (type transform transform)
1048 ram 1.15 (type (or function-type list) args))
1049 ram 1.50 (let* ((table (component-failed-optimizations *compile-component*))
1050     (found (assoc transform (gethash node table))))
1051 ram 1.15 (if found
1052     (setf (cdr found) args)
1053 ram 1.50 (push (cons transform args) (gethash node table))))
1054 ram 1.15 (undefined-value))
1055    
1056    
1057 wlott 1.1 ;;; IR1-Transform -- Internal
1058     ;;;
1059     ;;; Attempt to transform Node using Function, subject to the call type
1060     ;;; constraint Type. If we are inhibited from doing the transform for some
1061     ;;; reason and Flame is true, then we make a note of the message in
1062 ram 1.50 ;;; FAILED-OPTIMIZATIONS for IR1 finalize to pick up. We return true if
1063 wlott 1.2 ;;; the transform failed, and thus further transformation should be
1064     ;;; attempted. We return false if either the transform suceeded or was
1065     ;;; aborted.
1066 wlott 1.1 ;;;
1067 ram 1.28 (defun ir1-transform (node transform)
1068     (declare (type combination node) (type transform transform))
1069     (let* ((type (transform-type transform))
1070     (fun (transform-function transform))
1071     (constrained (function-type-p type))
1072 ram 1.50 (table (component-failed-optimizations *compile-component*))
1073 wlott 1.41 (flame
1074     (if (transform-important transform)
1075     (policy node (>= speed brevity))
1076     (policy node (> speed brevity))))
1077 ram 1.28 (*compiler-error-context* node))
1078 ram 1.60 (cond ((let ((when (transform-when transform)))
1079     (not (or (eq when :both)
1080     (eq when (if *byte-compiling* :byte :native)))))
1081     t)
1082     ((or (not constrained)
1083 ram 1.19 (valid-function-use node type :strict-result t))
1084 wlott 1.1 (multiple-value-bind
1085     (severity args)
1086     (catch 'give-up
1087     (transform-call node (funcall fun node))
1088     (values :none nil))
1089     (ecase severity
1090 ram 1.15 (:none
1091 ram 1.50 (remhash node table)
1092 ram 1.15 nil)
1093 wlott 1.1 (:aborted
1094 ram 1.50 (setf (combination-kind node) :error)
1095 wlott 1.1 (when args
1096 wlott 1.2 (apply #'compiler-warning args))
1097 ram 1.50 (remhash node table)
1098 wlott 1.2 nil)
1099 wlott 1.1 (:failure
1100 ram 1.15 (if args
1101     (when flame
1102 ram 1.28 (record-optimization-failure node transform args))
1103 ram 1.50 (setf (gethash node table)
1104     (remove transform (gethash node table) :key #'car)))
1105 dtc 1.72 t)
1106     (:delayed
1107     (remhash node table)
1108     nil))))
1109 wlott 1.1 ((and flame
1110     (valid-function-use node type
1111     :argument-test #'types-intersect
1112     :result-test #'values-types-intersect))
1113 ram 1.28 (record-optimization-failure node transform type)
1114 wlott 1.13 t)
1115     (t
1116 wlott 1.2 t))))
1117 wlott 1.1
1118 ram 1.50 (declaim (end-block))
1119 wlott 1.1
1120 dtc 1.72 ;;; give-up, abort-transform -- Interface
1121 wlott 1.1 ;;;
1122     ;;; Just throw the severity and args...
1123     ;;;
1124     (defun give-up (&rest args)
1125     "This function is used to throw out of an IR1 transform, aborting this
1126     attempt to transform the call, but admitting the possibility that this or
1127     some other transform will later suceed. If arguments are supplied, they are
1128     format arguments for an efficiency note."
1129 dtc 1.71 (values nil)
1130 wlott 1.1 (throw 'give-up (values :failure args)))
1131     ;;;
1132     (defun abort-transform (&rest args)
1133     "This function is used to throw out of an IR1 transform and force a normal
1134     call to the function at run time. No further optimizations will be
1135     attempted."
1136     (throw 'give-up (values :aborted args)))
1137 dtc 1.72
1138     (defvar *delayed-transforms*)
1139    
1140     ;;; delay-transform -- Interface
1141     ;;;
1142     (defun delay-transform (node &rest reasons)
1143     "This function is used to throw out of an IR1 transform, and delay the
1144     transform on the node until later. The reasons specifies when the transform
1145     will be later retried. The :optimize reason causes the transform to be
1146     delayed until after the current IR1 optimization pass. The :constraint
1147     reason causes the transform to be delayed until after constraint
1148     propagation."
1149     (let ((assoc (assoc node *delayed-transforms*)))
1150     (cond ((not assoc)
1151     (setf *delayed-transforms*
1152     (acons node reasons *delayed-transforms*))
1153     (throw 'give-up :delayed))
1154     ((cdr assoc)
1155     (dolist (reason reasons)
1156     (pushnew reason (cdr assoc)))
1157     (throw 'give-up :delayed)))))
1158    
1159     ;;; retry-delayed-transforms -- Interface.
1160     ;;;
1161     ;;; Clear any delayed transform with no reasons - these should have been tried
1162     ;;; in the last pass. Then remove the reason from the delayed transform
1163     ;;; reasons, and if any become empty then set reoptimize flags for the
1164     ;;; node. Returns true if any transforms are to be retried.
1165     ;;;
1166     (defun retry-delayed-transforms (reason)
1167     (setf *delayed-transforms* (remove-if-not #'cdr *delayed-transforms*))
1168     (let ((reoptimize nil))
1169     (dolist (assoc *delayed-transforms*)
1170     (let ((reasons (remove reason (cdr assoc))))
1171     (setf (cdr assoc) reasons)
1172     (unless reasons
1173     (let ((node (car assoc)))
1174     (unless (node-deleted node)
1175     (setf reoptimize t)
1176     (setf (node-reoptimize node) t)
1177     (let ((block (node-block node)))
1178     (setf (block-reoptimize block) t)
1179     (setf (component-reoptimize (block-component block)) t)))))))
1180     reoptimize))
1181 wlott 1.1
1182    
1183     ;;; Transform-Call -- Internal
1184     ;;;
1185     ;;; Take the lambda-expression Res, IR1 convert it in the proper
1186     ;;; environment, and then install it as the function for the call Node. We do
1187     ;;; local call analysis so that the new function is integrated into the control
1188 ram 1.50 ;;; flow.
1189 wlott 1.1 ;;;
1190     (defun transform-call (node res)
1191     (declare (type combination node) (list res))
1192     (with-ir1-environment node
1193 ram 1.50 (let ((new-fun (ir1-convert-inline-lambda res))
1194 wlott 1.1 (ref (continuation-use (combination-fun node))))
1195     (change-ref-leaf ref new-fun)
1196     (setf (combination-kind node) :full)
1197     (local-call-analyze *current-component*)))
1198     (undefined-value))
1199    
1200     ;;; Constant-Fold-Call -- Internal
1201     ;;;
1202     ;;; Replace a call to a foldable function of constant arguments with the
1203     ;;; result of evaluating the form. We insert the resulting constant node after
1204     ;;; the call, stealing the call's continuation. We give the call a
1205     ;;; continuation with no Dest, which should cause it and its arguments to go
1206     ;;; away. If there is an error during the evaluation, we give a warning and
1207 ram 1.50 ;;; leave the call alone, making the call a :ERROR call.
1208 wlott 1.1 ;;;
1209 ram 1.50 ;;; If there is more than one value, then we transform the call into a
1210     ;;; values form.
1211 wlott 1.1 ;;;
1212     (defun constant-fold-call (call)
1213     (declare (type combination call))
1214     (let* ((args (mapcar #'continuation-value (combination-args call)))
1215     (ref (continuation-use (combination-fun call)))
1216     (fun (leaf-name (ref-leaf ref))))
1217    
1218     (multiple-value-bind (values win)
1219 gerd 1.77 (careful-call fun args call "constant folding")
1220     (cond ((not win)
1221     (setf (combination-kind call) :error))
1222     ;;
1223     ;; Don't constand-fold a call if one of its arguments
1224     ;; requires a type check.
1225     ((or (policy call (< safety 3))
1226     (loop for arg in (basic-combination-args call)
1227     as check = (continuation-type-check arg)
1228     always (member check '(nil :deleted))))
1229     (let ((dummies (loop repeat (length args) collect (gensym))))
1230     (transform-call
1231     call
1232     `(lambda ,dummies
1233     (declare (ignore ,@dummies))
1234     (values ,@(mapcar (lambda (x) `',x) values)))))))))
1235     (values))
1236 wlott 1.1
1237    
1238     ;;;; Local call optimization:
1239    
1240 ram 1.50 (declaim (start-block ir1-optimize-set constant-reference-p delete-let
1241     propagate-let-args propagate-local-call-args
1242 ram 1.52 propagate-to-refs propagate-from-sets
1243     ir1-optimize-mv-combination))
1244 ram 1.50
1245 wlott 1.1 ;;; Propagate-To-Refs -- Internal
1246     ;;;
1247     ;;; Propagate Type to Leaf and its Refs, marking things changed. If the
1248     ;;; leaf type is a function type, then just leave it alone, since TYPE is never
1249     ;;; going to be more specific than that (and TYPE-INTERSECTION would choke.)
1250     ;;;
1251     (defun propagate-to-refs (leaf type)
1252     (declare (type leaf leaf) (type ctype type))
1253     (let ((var-type (leaf-type leaf)))
1254     (unless (function-type-p var-type)
1255     (let ((int (type-intersection var-type type)))
1256     (when (type/= int var-type)
1257     (setf (leaf-type leaf) int)
1258     (dolist (ref (leaf-refs leaf))
1259     (derive-node-type ref int))))
1260     (undefined-value))))
1261    
1262    
1263     ;;; PROPAGATE-FROM-SETS -- Internal
1264     ;;;
1265     ;;; Figure out the type of a LET variable that has sets. We compute the
1266     ;;; union of the initial value Type and the types of all the set values and to
1267     ;;; a PROPAGATE-TO-REFS with this type.
1268     ;;;
1269     (defun propagate-from-sets (var type)
1270 ram 1.6 (collect ((res type type-union))
1271 wlott 1.1 (dolist (set (basic-var-sets var))
1272     (res (continuation-type (set-value set)))
1273     (setf (node-reoptimize set) nil))
1274     (propagate-to-refs var (res)))
1275     (undefined-value))
1276    
1277    
1278     ;;; IR1-OPTIMIZE-SET -- Internal
1279     ;;;
1280     ;;; If a let variable, find the initial value's type and do
1281     ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's type.
1282     ;;;
1283     (defun ir1-optimize-set (node)
1284     (declare (type cset node))
1285     (let ((var (set-var node)))
1286     (when (and (lambda-var-p var) (leaf-refs var))
1287     (let ((home (lambda-var-home var)))
1288     (when (eq (functional-kind home) :let)
1289     (let ((iv (let-var-initial-value var)))
1290     (setf (continuation-reoptimize iv) nil)
1291     (propagate-from-sets var (continuation-type iv)))))))
1292    
1293     (derive-node-type node (continuation-type (set-value node)))
1294     (undefined-value))
1295    
1296    
1297 ram 1.17 ;;; CONSTANT-REFERENCE-P -- Interface
1298 ram 1.7 ;;;
1299     ;;; Return true if the value of Ref will always be the same (and is thus
1300 ram 1.50 ;;; legal to substitute.)
1301 ram 1.7 ;;;
1302     (defun constant-reference-p (ref)
1303     (declare (type ref ref))
1304     (let ((leaf (ref-leaf ref)))
1305     (typecase leaf
1306 ram 1.50 ((or constant functional) t)
1307 ram 1.7 (lambda-var
1308     (null (lambda-var-sets leaf)))
1309 ram 1.50 (defined-function
1310     (not (eq (defined-function-inlinep leaf) :notinline)))
1311 ram 1.7 (global-var
1312     (case (global-var-kind leaf)
1313 ram 1.50 (:global-function t)
1314 ram 1.7 (:constant t))))))
1315    
1316    
1317     ;;; SUBSTITUTE-SINGLE-USE-CONTINUATION -- Internal
1318     ;;;
1319     ;;; If we have a non-set let var with a single use, then (if possible)
1320     ;;; replace the variable reference's CONT with the arg continuation. This is
1321     ;;; inhibited when:
1322     ;;; -- CONT has other uses, or
1323     ;;; -- CONT receives multiple values, or
1324 ram 1.9 ;;; -- the reference is in a different environment from the variable, or
1325     ;;; -- either continuation has a funky TYPE-CHECK annotation.
1326 ram 1.43 ;;; -- the continuations have incompatible assertions, so the new asserted type
1327     ;;; would be NIL.
1328 dtc 1.68 ;;; -- CONT's assertion is incompatbile with the proven type of ARG's, such as
1329     ;;; when ARG returns multiple values and CONT has a single value assertion.
1330 ram 1.27 ;;; -- the var's DEST has a different policy than the ARG's (think safety).
1331 ram 1.7 ;;;
1332     ;;; We change the Ref to be a reference to NIL with unused value, and let it
1333     ;;; be flushed as dead code. A side-effect of this substitution is to delete
1334     ;;; the variable.
1335     ;;;
1336     (defun substitute-single-use-continuation (arg var)
1337     (declare (type continuation arg) (type lambda-var var))
1338     (let* ((ref (first (leaf-refs var)))
1339     (cont (node-cont ref))
1340 ram 1.43 (cont-atype (continuation-asserted-type cont))
1341 ram 1.7 (dest (continuation-dest cont)))
1342     (when (and (eq (continuation-use cont) ref)
1343     dest
1344     (not (typep dest '(or creturn exit mv-combination)))
1345 ram 1.11 (eq (node-home-lambda ref)
1346 ram 1.9 (lambda-home (lambda-var-home var)))
1347     (member (continuation-type-check arg) '(t nil))
1348 ram 1.27 (member (continuation-type-check cont) '(t nil))
1349 ram 1.43 (not (eq (values-type-intersection
1350 dtc 1.68 cont-atype (continuation-asserted-type arg))
1351     *empty-type*))
1352     (not (eq (values-type-intersection
1353     cont-atype (continuation-proven-type arg))
1354 ram 1.43 *empty-type*))
1355 ram 1.27 (eq (lexenv-cookie (node-lexenv dest))
1356     (lexenv-cookie (node-lexenv (continuation-dest arg)))))
1357 ram 1.25 (assert (member (continuation-kind arg)
1358     '(:block-start :deleted-block-start :inside-block)))
1359 ram 1.43 (assert-continuation-type arg cont-atype)
1360 ram 1.34 (setf (node-derived-type ref) *wild-type*)
1361 ram 1.7 (change-ref-leaf ref (find-constant nil))
1362     (substitute-continuation arg cont)
1363     (reoptimize-continuation arg)
1364     t)))
1365    
1366    
1367 ram 1.19 ;;; DELETE-LET -- Interface
1368     ;;;
1369     ;;; Delete a Let, removing the call and bind nodes, and warning about any
1370     ;;; unreferenced variables. Note that FLUSH-DEAD-CODE will come along right
1371     ;;; away and delete the REF and then the lambda, since we flush the FUN
1372     ;;; continuation.
1373     ;;;
1374     (defun delete-let (fun)
1375     (declare (type clambda fun))
1376 ram 1.42 (assert (member (functional-kind fun) '(:let :mv-let)))
1377 ram 1.19 (note-unreferenced-vars fun)
1378     (let ((call (let-combination fun)))
1379 ram 1.42 (flush-dest (basic-combination-fun call))
1380 ram 1.19 (unlink-node call)
1381     (unlink-node (lambda-bind fun))
1382     (setf (lambda-bind fun) nil))
1383     (undefined-value))
1384    
1385    
1386 wlott 1.1 ;;; Propagate-Let-Args -- Internal
1387     ;;;
1388     ;;; This function is called when one of the arguments to a LET changes. We
1389     ;;; look at each changed argument. If the corresponding variable is set, then
1390     ;;; we call PROPAGATE-FROM-SETS. Otherwise, we consider substituting for the
1391     ;;; variable, and also propagate derived-type information for the arg to all
1392     ;;; the Var's refs.
1393     ;;;
1394 ram 1.16 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1395     ;;; subtype of the argument's asserted type. This prevents type checking from
1396     ;;; being defeated, and also ensures that the best representation for the
1397     ;;; variable can be used.
1398 wlott 1.1 ;;;
1399 ram 1.26 ;;; Substitution of individual references is inhibited if the reference is
1400     ;;; in a different component from the home. This can only happen with closures
1401     ;;; over top-level lambda vars. In such cases, the references may have already
1402     ;;; been compiled, and thus can't be retroactively modified.
1403     ;;;
1404 dtc 1.73 ;;; If all of the variables are deleted (have no references) when we are
1405     ;;; done, then we delete the let.
1406 ram 1.19 ;;;
1407 wlott 1.1 ;;; Note that we are responsible for clearing the Continuation-Reoptimize
1408     ;;; flags.
1409     ;;;
1410     (defun propagate-let-args (call fun)
1411     (declare (type combination call) (type clambda fun))
1412 ram 1.19 (loop for arg in (combination-args call)
1413     and var in (lambda-vars fun) do
1414     (when (and arg (continuation-reoptimize arg))
1415     (setf (continuation-reoptimize arg) nil)
1416     (cond
1417     ((lambda-var-sets var)
1418     (propagate-from-sets var (continuation-type arg)))
1419     ((let ((use (continuation-use arg)))
1420     (when (ref-p use)
1421     (let ((leaf (ref-leaf use)))
1422     (when (and (constant-reference-p use)
1423     (values-subtypep (leaf-type leaf)
1424     (continuation-asserted-type arg)))
1425     (propagate-to-refs var (continuation-type arg))
1426 ram 1.26 (let ((this-comp (block-component (node-block use))))
1427     (substitute-leaf-if
1428     #'(lambda (ref)
1429     (cond ((eq (block-component (node-block ref))
1430     this-comp)
1431     t)
1432     (t
1433     (assert (eq (functional-kind (lambda-home fun))
1434     :top-level))
1435     nil)))
1436     leaf var))
1437 ram 1.19 t)))))
1438     ((and (null (rest (leaf-refs var)))
1439 wlott 1.47 (not *byte-compiling*)
1440 ram 1.19 (substitute-single-use-continuation arg var)))
1441     (t
1442     (propagate-to-refs var (continuation-type arg))))))
1443 dtc 1.73
1444     (when (every #'null (combination-args call))
1445 ram 1.19 (delete-let fun))
1446    
1447 wlott 1.1 (undefined-value))
1448    
1449    
1450     ;;; Propagate-Local-Call-Args -- Internal
1451     ;;;
1452     ;;; This function is called when one of the args to a non-let local call
1453     ;;; changes. For each changed argument corresponding to an unset variable, we
1454     ;;; compute the union of the types across all calls and propagate this type
1455     ;;; information to the var's refs.
1456     ;;;
1457     ;;; If the function has an XEP, then we don't do anything, since we won't
1458     ;;; discover anything.
1459     ;;;
1460     ;;; We can clear the Continuation-Reoptimize flags for arguments in all calls
1461     ;;; corresponding to changed arguments in Call, since the only use in IR1
1462     ;;; optimization of the Reoptimize flag for local call args is right here.
1463     ;;;
1464     (defun propagate-local-call-args (call fun)
1465     (declare (type combination call) (type clambda fun))
1466    
1467 ram 1.64 (unless (or (functional-entry-function fun)
1468     (lambda-optional-dispatch fun))
1469 wlott 1.1 (let* ((vars (lambda-vars fun))
1470     (union (mapcar #'(lambda (arg var)
1471     (when (and arg
1472     (continuation-reoptimize arg)
1473     (null (basic-var-sets var)))
1474     (continuation-type arg)))
1475     (basic-combination-args call)
1476     vars))
1477     (this-ref (continuation-use (basic-combination-fun call))))
1478    
1479     (dolist (arg (basic-combination-args call))
1480     (when arg
1481     (setf (continuation-reoptimize arg) nil)))
1482    
1483     (dolist (ref (leaf-refs fun))
1484 ram 1.63 (let ((dest (continuation-dest (node-cont ref))))
1485     (unless (or (eq ref this-ref) (not dest))
1486     (setq union
1487     (mapcar #'(lambda (this-arg old)
1488     (when old
1489     (setf (continuation-reoptimize this-arg) nil)
1490     (type-union (continuation-type this-arg) old)))
1491     (basic-combination-args dest)
1492     union)))))
1493 wlott 1.1
1494     (mapc #'(lambda (var type)
1495     (when type
1496     (propagate-to-refs var type)))
1497     vars union)))
1498    
1499 ram 1.6 (undefined-value))
1500    
1501 ram 1.50 (declaim (end-block))
1502    
1503 ram 1.6
1504 ram 1.19 ;;;; Multiple values optimization:
1505    
1506 ram 1.21 ;;; IR1-OPTIMIZE-MV-COMBINATION -- Internal
1507     ;;;
1508 ram 1.32 ;;; Do stuff to notice a change to a MV combination node. There are two
1509     ;;; main branches here:
1510     ;;; -- If the call is local, then it is already a MV let, or should become one.
1511     ;;; Note that although all :LOCAL MV calls must eventually be converted to
1512     ;;; :MV-LETs, there can be a window when the call is local, but has not
1513     ;;; been let converted yet. This is because the entry-point lambdas may
1514     ;;; have stray references (in other entry points) that have not been
1515     ;;; deleted yet.
1516     ;;; -- The call is full. This case is somewhat similar to the non-MV
1517     ;;; combination optimization: we propagate return type information and
1518     ;;; notice non-returning calls. We also have an optimization
1519     ;;; which tries to convert MV-CALLs into MV-binds.
1520 ram 1.21 ;;;
1521     (defun ir1-optimize-mv-combination (node)
1522 ram 1.50 (ecase (basic-combination-kind node)
1523     (:local
1524 ram 1.54 (let ((fun-cont (basic-combination-fun node)))
1525     (when (continuation-reoptimize fun-cont)
1526     (setf (continuation-reoptimize fun-cont) nil)
1527 ram 1.50 (maybe-let-convert (combination-lambda node))))
1528     (setf (continuation-reoptimize (first (basic-combination-args node))) nil)
1529     (when (eq (functional-kind (combination-lambda node)) :mv-let)
1530     (unless (convert-mv-bind-to-let node)
1531     (ir1-optimize-mv-bind node))))
1532     (:full
1533     (let* ((fun (basic-combination-fun node))
1534     (fun-changed (continuation-reoptimize fun))
1535     (args (basic-combination-args node)))
1536     (when fun-changed
1537     (setf (continuation-reoptimize fun) nil)
1538     (let ((type (continuation-type fun)))
1539     (when (function-type-p type)
1540     (derive-node-type node (function-type-returns type))))
1541     (maybe-terminate-block node nil)
1542     (let ((use (continuation-use fun)))
1543     (when (and (ref-p use) (functional-p (ref-leaf use)))
1544     (convert-call-if-possible use node)
1545 ram 1.54 (when (eq (basic-combination-kind node) :local)
1546     (maybe-let-convert (ref-leaf use))))))
1547 ram 1.50 (unless (or (eq (basic-combination-kind node) :local)
1548     (eq (continuation-function-name fun) '%throw))
1549     (ir1-optimize-mv-call node))
1550     (dolist (arg args)
1551     (setf (continuation-reoptimize arg) nil))))
1552     (:error))
1553 ram 1.21 (undefined-value))
1554    
1555    
1556 dtc 1.69 ;;; Values-types-defaulted -- Internal
1557     ;;;
1558     ;;; Like values-types, but returns the types of the given number of
1559     ;;; arguments. If optional of rest values must be used then the union
1560     ;;; with the null type is computed in case of defaulting, and if no
1561     ;;; values are available then they are defaulted to the null type.
1562     ;;;
1563     (defun values-types-defaulted (type count)
1564     (declare (type ctype type) (type index count))
1565     (cond ((eq type *wild-type*)
1566     (let ((types nil))
1567     (dotimes (i count types)
1568     (push *universal-type* types))))
1569     ((not (values-type-p type))
1570     (let ((types nil))
1571     (dotimes (i (1- count))
1572     (push *null-type* types))
1573     (push type types)))
1574     (t
1575     (let ((required (args-type-required type))
1576     (optional (args-type-optional type))
1577     (keyp-allowp (or (args-type-keyp type) (args-type-allowp type)))
1578     (rest (args-type-rest type)))
1579     (collect ((types))
1580     (dotimes (i count)
1581     (types (cond (required (single-value-type (pop required)))
1582     (optional (values-type-union
1583     (single-value-type (pop optional))
1584     *null-type*))
1585     (keyp-allowp *universal-type*)
1586     (rest (values-type-union (single-value-type rest)
1587     *null-type*))
1588     (t *null-type*))))
1589     (types))))))
1590    
1591    
1592 ram 1.6 ;;; IR1-OPTIMIZE-MV-BIND -- Internal
1593     ;;;
1594     ;;; Propagate derived type info from the values continuation to the vars.
1595     ;;;
1596     (defun ir1-optimize-mv-bind (node)
1597     (declare (type mv-combination node))
1598     (let ((arg (first (basic-combination-args node)))
1599     (vars (lambda-vars (combination-lambda node))))
1600 dtc 1.69 (let ((types (values-types-defaulted (continuation-derived-type arg)
1601     (length vars))))
1602     (mapc #'(lambda (var type)
1603     (if (basic-var-sets var)
1604     (propagate-from-sets var type)
1605     (propagate-to-refs var type)))
1606     vars types))
1607 ram 1.6
1608     (setf (continuation-reoptimize arg) nil))
1609 wlott 1.1 (undefined-value))
1610 ram 1.19
1611    
1612 ram 1.21 ;;; IR1-OPTIMIZE-MV-CALL -- Internal
1613 ram 1.19 ;;;
1614 ram 1.21 ;;; If possible, convert a general MV call to an MV-BIND. We can do this
1615     ;;; if:
1616 ram 1.22 ;;; -- The call has only one argument, and
1617 ram 1.21 ;;; -- The function has a known fixed number of arguments, or
1618 ram 1.22 ;;; -- The argument yields a known fixed number of values.
1619 ram 1.21 ;;;
1620     ;;; What we do is change the function in the MV-CALL to be a lambda that "looks
1621     ;;; like an MV bind", which allows IR1-OPTIMIZE-MV-COMBINATION to notice that
1622     ;;; this call can be converted (the next time around.) This new lambda just
1623 ram 1.31 ;;; calls the actual function with the MV-BIND variables as arguments. Note
1624     ;;; that this new MV bind is not let-converted immediately, as there are going
1625     ;;; to be stray references from the entry-point functions until they get
1626     ;;; deleted.
1627 ram 1.21 ;;;
1628     ;;; In order to avoid loss of argument count checking, we only do the
1629     ;;; transformation according to a known number of expected argument if safety
1630     ;;; is unimportant. We can always convert if we know the number of actual
1631     ;;; values, since the normal call that we build will still do any appropriate
1632     ;;; argument count checking.
1633     ;;;
1634     ;;; We only attempt the transformation if the called function is a constant
1635     ;;; reference. This allows us to just splice the leaf into the new function,
1636     ;;; instead of trying to somehow bind the function expression. The leaf must
1637     ;;; be constant because we are evaluating it again in a different place. This
1638     ;;; also has the effect of squelching multiple warnings when there is an
1639     ;;; argument count error.
1640     ;;;
1641     (defun ir1-optimize-mv-call (node)
1642     (let ((fun (basic-combination-fun node))
1643     (*compiler-error-context* node)
1644 ram 1.22 (ref (continuation-use (basic-combination-fun node)))
1645     (args (basic-combination-args node)))
1646 ram 1.21
1647 ram 1.22 (unless (and (ref-p ref) (constant-reference-p ref)
1648     args (null (rest args)))
1649 ram 1.21 (return-from ir1-optimize-mv-call))
1650    
1651     (multiple-value-bind (min max)
1652     (function-type-nargs (continuation-type fun))
1653 ram 1.22 (let ((total-nvals
1654     (multiple-value-bind
1655     (types nvals)
1656     (values-types (continuation-derived-type (first args)))
1657     (declare (ignore types))
1658     (if (eq nvals :unknown) nil nvals))))
1659 ram 1.21
1660 ram 1.22 (when total-nvals
1661     (when (and min (< total-nvals min))
1662     (compiler-warning
1663     "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1664     at least ~R."
1665     total-nvals min)
1666 ram 1.50 (setf (basic-combination-kind node) :error)
1667 ram 1.22 (return-from ir1-optimize-mv-call))
1668     (when (and max (> total-nvals max))
1669     (compiler-warning
1670     "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1671     at most ~R."
1672     total-nvals max)
1673 ram 1.50 (setf (basic-combination-kind node) :error)
1674 ram 1.22 (return-from ir1-optimize-mv-call)))
1675 ram 1.21
1676 ram 1.22 (let ((count (cond (total-nvals)
1677     ((and (policy node (zerop safety)) (eql min max))
1678     min)
1679     (t nil))))
1680     (when count
1681     (with-ir1-environment node
1682     (let* ((dums (loop repeat count collect (gensym)))
1683     (ignore (gensym))
1684     (fun (ir1-convert-lambda
1685     `(lambda (&optional ,@dums &rest ,ignore)
1686     (declare (ignore ,ignore))
1687 rtoy 1.83 (funcall ,(ref-leaf ref) ,@dums))
1688     nil ; name
1689     nil ; parent-form
1690     nil ; allow-debug-catch-tag
1691     'ir1-optimize-mv-call ; caller
1692     )))
1693 ram 1.22 (change-ref-leaf ref fun)
1694     (assert (eq (basic-combination-kind node) :full))
1695     (local-call-analyze *current-component*)
1696 ram 1.23 (assert (eq (basic-combination-kind node) :local)))))))))
1697 ram 1.21 (undefined-value))
1698    
1699    
1700     ;;; CONVERT-MV-BIND-TO-LET -- Internal
1701     ;;;
1702 ram 1.19 ;;; If we see:
1703     ;;; (multiple-value-bind (x y)
1704     ;;; (values xx yy)
1705     ;;; ...)
1706     ;;; Convert to:
1707     ;;; (let ((x xx)
1708     ;;; (y yy))
1709     ;;; ...)
1710     ;;;
1711     ;;; What we actually do is convert the VALUES combination into a normal let
1712 ram 1.31 ;;; combination calling the original :MV-LET lambda. If there are extra args to
1713 ram 1.19 ;;; VALUES, discard the corresponding continuations. If there are insufficient
1714     ;;; args, insert references to NIL.
1715     ;;;
1716 ram 1.21 (defun convert-mv-bind-to-let (call)
1717     (declare (type mv-combination call))
1718     (let* ((arg (first (basic-combination-args call)))
1719     (use (continuation-use arg)))
1720     (when (and (combination-p use)
1721     (eq (continuation-function-name (combination-fun use))
1722     'values))
1723     (let* ((fun (combination-lambda call))
1724 ram 1.19 (vars (lambda-vars fun))
1725 ram 1.21 (vals (combination-args use))
1726 ram 1.19 (nvars (length vars))
1727     (nvals (length vals)))
1728     (cond ((> nvals nvars)
1729     (mapc #'flush-dest (subseq vals nvars))
1730     (setq vals (subseq vals 0 nvars)))
1731     ((< nvals nvars)
1732 ram 1.21 (with-ir1-environment use
1733     (let ((node-prev (node-prev use)))
1734     (setf (node-prev use) nil)
1735 ram 1.19 (setf (continuation-next node-prev) nil)
1736     (collect ((res vals))
1737 ram 1.21 (loop as cont = (make-continuation use)
1738 ram 1.19 and prev = node-prev then cont
1739     repeat (- nvars nvals)
1740     do (reference-constant prev cont nil)
1741     (res cont))
1742     (setq vals (res)))
1743 ram 1.21 (prev-link use (car (last vals)))))))
1744     (setf (combination-args use) vals)
1745     (flush-dest (combination-fun use))
1746     (let ((fun-cont (basic-combination-fun call)))
1747     (setf (continuation-dest fun-cont) use)
1748     (setf (combination-fun use) fun-cont))
1749     (setf (combination-kind use) :local)
1750 ram 1.19 (setf (functional-kind fun) :let)
1751 ram 1.21 (flush-dest (first (basic-combination-args call)))
1752     (unlink-node call)
1753 ram 1.19 (when vals
1754 ram 1.20 (reoptimize-continuation (first vals)))
1755 ram 1.21 (propagate-to-args use fun))
1756     t)))
1757    
1758    
1759     ;;; VALUES-LIST IR1 optimizer -- Internal
1760     ;;;
1761     ;;; If we see:
1762     ;;; (values-list (list x y z))
1763     ;;;
1764     ;;; Convert to:
1765     ;;; (values x y z)
1766     ;;;
1767     ;;; In implementation, this is somewhat similar to CONVERT-MV-BIND-TO-LET. We
1768     ;;; grab the args of LIST and make them args of the VALUES-LIST call, flushing
1769     ;;; the old argument continuation (allowing the LIST to be flushed.)
1770     ;;;
1771     (defoptimizer (values-list optimizer) ((list) node)
1772     (let ((use (continuation-use list)))
1773     (when (and (combination-p use)
1774     (eq (continuation-function-name (combination-fun use))
1775     'list))
1776     (change-ref-leaf (continuation-use (combination-fun node))
1777     (find-free-function 'values "in a strange place"))
1778     (setf (combination-kind node) :full)
1779     (let ((args (combination-args use)))
1780     (dolist (arg args)
1781     (setf (continuation-dest arg) node))
1782     (setf (combination-args use) nil)
1783     (flush-dest list)
1784     (setf (combination-args node) args))
1785 ram 1.19 t)))
1786    
1787    
1788     ;;; VALUES IR1 transform -- Internal
1789     ;;;
1790     ;;; If VALUES appears in a non-MV context, then effectively convert it to a
1791     ;;; PROG1. This allows the computation of the additional values to become dead
1792 dtc 1.68 ;;; code. Some attempt is made to correct the node derived type, setting it to
1793     ;;; the received single-value-type. The node continuation asserted type must
1794     ;;; also be adjusted, taking care when the continuation has multiple uses.
1795 ram 1.19 ;;;
1796     (deftransform values ((&rest vals) * * :node node)
1797 dtc 1.68 (let ((cont (node-cont node)))
1798     (when (typep (continuation-dest cont) '(or creturn exit mv-combination))
1799     (give-up))
1800     (flet ((first-value-type (type)
1801     (declare (type ctype type))
1802     (cond ((values-type-p type)
1803     (let ((required (args-type-required type)))
1804     (if required
1805     (first required)
1806     (let ((otype (args-type-optional type)))
1807     (cond (otype (first otype))
1808     ((or (args-type-keyp type)
1809     (args-type-allowp type))
1810     *universal-type*)
1811     ((args-type-rest type))
1812     (t *null-type*))))))
1813     ((eq type *wild-type*)
1814     *universal-type*)
1815     (t
1816     type))))
1817     (cond ((= (length (find-uses cont)) 1)
1818     (setf (node-derived-type node)
1819     (single-value-type (node-derived-type node)))
1820     (setf (continuation-asserted-type cont)
1821     (first-value-type (continuation-asserted-type cont))))
1822     (t
1823     (setf (node-derived-type node)
1824     (single-value-type (node-derived-type node)))
1825     (setf (continuation-asserted-type cont)
1826     (values-type-union (continuation-asserted-type cont)
1827     (first-value-type
1828     (continuation-asserted-type cont)))))))
1829     (reoptimize-continuation cont)
1830     (if vals
1831     (let ((dummies (loop repeat (1- (length vals))
1832     collect (gensym))))
1833     `(lambda (val ,@dummies)
1834     (declare (ignore ,@dummies))
1835     val))
1836     'nil)))

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