1 ;;;; This file contains miscellaneous utilities used for manipulating
2 ;;;; the IR1 representation.
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
17 ;;; Return the innermost cleanup enclosing NODE, or NIL if there is
18 ;;; none in its function. If NODE has no cleanup, but is in a LET,
19 ;;; then we must still check the environment that the call is in.
20 (defun node-enclosing-cleanup (node)
21 (declare (type node node))
22 (do ((lexenv (node-lexenv node)
23 (lambda-call-lexenv (lexenv-lambda lexenv))))
25 (let ((cup (lexenv-cleanup lexenv)))
26 (when cup (return cup)))))
28 ;;; Convert the FORM in a block inserted between BLOCK1 and BLOCK2 as
29 ;;; an implicit MV-PROG1. The inserted block is returned. NODE is used
30 ;;; for IR1 context when converting the form. Note that the block is
31 ;;; not assigned a number, and is linked into the DFO at the
32 ;;; beginning. We indicate that we have trashed the DFO by setting
33 ;;; COMPONENT-REANALYZE. If CLEANUP is supplied, then convert with
35 (defun insert-cleanup-code (block1 block2 node form &optional cleanup)
36 (declare (type cblock block1 block2) (type node node)
37 (type (or cleanup null) cleanup))
38 (setf (component-reanalyze (block-component block1)) t)
39 (with-ir1-environment-from-node node
40 (with-component-last-block (*current-component*
41 (block-next (component-head *current-component*)))
42 (let* ((start (make-ctran))
43 (block (ctran-starts-block start))
46 (make-lexenv :cleanup cleanup)
48 (change-block-successor block1 block2 block)
49 (link-blocks block block2)
50 (ir1-convert start next nil form)
51 (setf (block-last block) (ctran-use next))
52 (setf (node-next (block-last block)) nil)
57 ;;; Return a list of all the nodes which use LVAR.
58 (declaim (ftype (sfunction (lvar) list) find-uses))
59 (defun find-uses (lvar)
60 (let ((uses (lvar-uses lvar)))
65 (defun principal-lvar-use (lvar)
67 (declare (type lvar lvar))
68 (let ((use (lvar-uses lvar)))
70 (plu (cast-value use))
74 ;;; Update lvar use information so that NODE is no longer a use of its
77 ;;; Note: if you call this function, you may have to do a
78 ;;; REOPTIMIZE-LVAR to inform IR1 optimization that something has
80 (declaim (ftype (sfunction (node) (values))
83 ;;; Just delete NODE from its LVAR uses; LVAR is preserved so it may
84 ;;; be given a new use.
85 (defun %delete-lvar-use (node)
86 (let ((lvar (node-lvar node)))
88 (if (listp (lvar-uses lvar))
89 (let ((new-uses (delq node (lvar-uses lvar))))
90 (setf (lvar-uses lvar)
91 (if (singleton-p new-uses)
94 (setf (lvar-uses lvar) nil))
95 (setf (node-lvar node) nil)))
97 ;;; Delete NODE from its LVAR uses; if LVAR has no other uses, delete
98 ;;; its DEST's block, which must be unreachable.
99 (defun delete-lvar-use (node)
100 (let ((lvar (node-lvar node)))
102 (%delete-lvar-use node)
103 (if (null (lvar-uses lvar))
104 (binding* ((dest (lvar-dest lvar) :exit-if-null)
105 (() (not (node-deleted dest)) :exit-if-null)
106 (block (node-block dest)))
107 (mark-for-deletion block))
108 (reoptimize-lvar lvar))))
111 ;;; Update lvar use information so that NODE uses LVAR.
113 ;;; Note: if you call this function, you may have to do a
114 ;;; REOPTIMIZE-LVAR to inform IR1 optimization that something has
116 (declaim (ftype (sfunction (node (or lvar null)) (values)) add-lvar-use))
117 (defun add-lvar-use (node lvar)
118 (aver (not (node-lvar node)))
120 (let ((uses (lvar-uses lvar)))
121 (setf (lvar-uses lvar)
128 (setf (node-lvar node) lvar)))
132 ;;; Return true if LVAR destination is executed immediately after
133 ;;; NODE. Cleanups are ignored.
134 (defun immediately-used-p (lvar node)
135 (declare (type lvar lvar) (type node node))
136 (aver (eq (node-lvar node) lvar))
137 (let ((dest (lvar-dest lvar)))
138 (acond ((node-next node)
139 (eq (ctran-next it) dest))
140 (t (eq (block-start (first (block-succ (node-block node))))
141 (node-prev dest))))))
143 ;;;; lvar substitution
145 ;;; In OLD's DEST, replace OLD with NEW. NEW's DEST must initially be
146 ;;; NIL. We do not flush OLD's DEST.
147 (defun substitute-lvar (new old)
148 (declare (type lvar old new))
149 (aver (not (lvar-dest new)))
150 (let ((dest (lvar-dest old)))
153 (cif (setf (if-test dest) new))
154 (cset (setf (set-value dest) new))
155 (creturn (setf (return-result dest) new))
156 (exit (setf (exit-value dest) new))
158 (if (eq old (basic-combination-fun dest))
159 (setf (basic-combination-fun dest) new)
160 (setf (basic-combination-args dest)
161 (nsubst new old (basic-combination-args dest)))))
162 (cast (setf (cast-value dest) new)))
164 (setf (lvar-dest old) nil)
165 (setf (lvar-dest new) dest)
166 (flush-lvar-externally-checkable-type new))
169 ;;; Replace all uses of OLD with uses of NEW, where NEW has an
170 ;;; arbitary number of uses. NEW is supposed to be "later" than OLD.
171 (defun substitute-lvar-uses (new old propagate-dx)
172 (declare (type lvar old)
173 (type (or lvar null) new)
174 (type boolean propagate-dx))
178 (%delete-lvar-use node)
179 (add-lvar-use node new))
180 (reoptimize-lvar new)
181 (awhen (and propagate-dx (lvar-dynamic-extent old))
182 (setf (lvar-dynamic-extent old) nil)
183 (unless (lvar-dynamic-extent new)
184 (setf (lvar-dynamic-extent new) it)
185 (setf (cleanup-info it) (substitute new old (cleanup-info it)))))
186 (when (lvar-dynamic-extent new)
188 (node-ends-block node))))
189 (t (flush-dest old)))
193 ;;;; block starting/creation
195 ;;; Return the block that CTRAN is the start of, making a block if
196 ;;; necessary. This function is called by IR1 translators which may
197 ;;; cause a CTRAN to be used more than once. Every CTRAN which may be
198 ;;; used more than once must start a block by the time that anyone
199 ;;; does a USE-CTRAN on it.
201 ;;; We also throw the block into the next/prev list for the
202 ;;; *CURRENT-COMPONENT* so that we keep track of which blocks we have
204 (defun ctran-starts-block (ctran)
205 (declare (type ctran ctran))
206 (ecase (ctran-kind ctran)
208 (aver (not (ctran-block ctran)))
209 (let* ((next (component-last-block *current-component*))
210 (prev (block-prev next))
211 (new-block (make-block ctran)))
212 (setf (block-next new-block) next
213 (block-prev new-block) prev
214 (block-prev next) new-block
215 (block-next prev) new-block
216 (ctran-block ctran) new-block
217 (ctran-kind ctran) :block-start)
218 (aver (not (ctran-use ctran)))
221 (ctran-block ctran))))
223 ;;; Ensure that CTRAN is the start of a block so that the use set can
224 ;;; be freely manipulated.
225 (defun ensure-block-start (ctran)
226 (declare (type ctran ctran))
227 (let ((kind (ctran-kind ctran)))
231 (setf (ctran-block ctran)
232 (make-block-key :start ctran))
233 (setf (ctran-kind ctran) :block-start))
235 (node-ends-block (ctran-use ctran)))))
238 ;;; CTRAN must be the last ctran in an incomplete block; finish the
239 ;;; block and start a new one if necessary.
240 (defun start-block (ctran)
241 (declare (type ctran ctran))
242 (aver (not (ctran-next ctran)))
243 (ecase (ctran-kind ctran)
245 (let ((block (ctran-block ctran))
246 (node (ctran-use ctran)))
247 (aver (not (block-last block)))
249 (setf (block-last block) node)
250 (setf (node-next node) nil)
251 (setf (ctran-use ctran) nil)
252 (setf (ctran-kind ctran) :unused)
253 (setf (ctran-block ctran) nil)
254 (link-blocks block (ctran-starts-block ctran))))
259 ;;; Filter values of LVAR through FORM, which must be an ordinary/mv
260 ;;; call. First argument must be 'DUMMY, which will be replaced with
261 ;;; LVAR. In case of an ordinary call the function should not have
262 ;;; return type NIL. We create a new "filtered" lvar.
264 ;;; TODO: remove preconditions.
265 (defun filter-lvar (lvar form)
266 (declare (type lvar lvar) (type list form))
267 (let* ((dest (lvar-dest lvar))
268 (ctran (node-prev dest)))
269 (with-ir1-environment-from-node dest
271 (ensure-block-start ctran)
272 (let* ((old-block (ctran-block ctran))
273 (new-start (make-ctran))
274 (filtered-lvar (make-lvar))
275 (new-block (ctran-starts-block new-start)))
277 ;; Splice in the new block before DEST, giving the new block
278 ;; all of DEST's predecessors.
279 (dolist (block (block-pred old-block))
280 (change-block-successor block old-block new-block))
282 (ir1-convert new-start ctran filtered-lvar form)
284 ;; KLUDGE: Comments at the head of this function in CMU CL
285 ;; said that somewhere in here we
286 ;; Set the new block's start and end cleanups to the *start*
287 ;; cleanup of PREV's block. This overrides the incorrect
288 ;; default from WITH-IR1-ENVIRONMENT-FROM-NODE.
289 ;; Unfortunately I can't find any code which corresponds to this.
290 ;; Perhaps it was a stale comment? Or perhaps I just don't
291 ;; understand.. -- WHN 19990521
293 ;; Replace 'DUMMY with the LVAR. (We can find 'DUMMY because
294 ;; no LET conversion has been done yet.) The [mv-]combination
295 ;; code from the call in the form will be the use of the new
296 ;; check lvar. We substitute for the first argument of
298 (let* ((node (lvar-use filtered-lvar))
299 (args (basic-combination-args node))
300 (victim (first args)))
301 (aver (eq (constant-value (ref-leaf (lvar-use victim)))
304 (substitute-lvar filtered-lvar lvar)
305 (substitute-lvar lvar victim)
308 ;; Invoking local call analysis converts this call to a LET.
309 (locall-analyze-component *current-component*))))
312 ;;; Delete NODE and VALUE. It may result in some calls becoming tail.
313 (defun delete-filter (node lvar value)
314 (aver (eq (lvar-dest value) node))
315 (aver (eq (node-lvar node) lvar))
316 (cond (lvar (collect ((merges))
317 (when (return-p (lvar-dest lvar))
319 (when (and (basic-combination-p use)
320 (eq (basic-combination-kind use) :local))
322 (substitute-lvar-uses lvar value
323 (and lvar (eq (lvar-uses lvar) node)))
324 (%delete-lvar-use node)
327 (dolist (merge (merges))
328 (merge-tail-sets merge)))))
329 (t (flush-dest value)
330 (unlink-node node))))
332 ;;; Make a CAST and insert it into IR1 before node NEXT.
333 (defun insert-cast-before (next lvar type policy)
334 (declare (type node next) (type lvar lvar) (type ctype type))
335 (with-ir1-environment-from-node next
336 (let* ((ctran (node-prev next))
337 (cast (make-cast lvar type policy))
338 (internal-ctran (make-ctran)))
339 (setf (ctran-next ctran) cast
340 (node-prev cast) ctran)
341 (use-ctran cast internal-ctran)
342 (link-node-to-previous-ctran next internal-ctran)
343 (setf (lvar-dest lvar) cast)
344 (reoptimize-lvar lvar)
345 (when (return-p next)
346 (node-ends-block cast))
347 (setf (block-attributep (block-flags (node-block cast))
348 type-check type-asserted)
352 ;;;; miscellaneous shorthand functions
354 ;;; Return the home (i.e. enclosing non-LET) CLAMBDA for NODE. Since
355 ;;; the LEXENV-LAMBDA may be deleted, we must chain up the
356 ;;; LAMBDA-CALL-LEXENV thread until we find a CLAMBDA that isn't
357 ;;; deleted, and then return its home.
358 (defun node-home-lambda (node)
359 (declare (type node node))
360 (do ((fun (lexenv-lambda (node-lexenv node))
361 (lexenv-lambda (lambda-call-lexenv fun))))
362 ((not (memq (functional-kind fun) '(:deleted :zombie)))
364 (when (eq (lambda-home fun) fun)
367 #!-sb-fluid (declaim (inline node-block))
368 (defun node-block (node)
369 (ctran-block (node-prev node)))
370 (declaim (ftype (sfunction (node) component) node-component))
371 (defun node-component (node)
372 (block-component (node-block node)))
373 (declaim (ftype (sfunction (node) physenv) node-physenv))
374 (defun node-physenv (node)
375 (lambda-physenv (node-home-lambda node)))
376 #!-sb-fluid (declaim (inline node-dest))
377 (defun node-dest (node)
378 (awhen (node-lvar node) (lvar-dest it)))
380 #!-sb-fluid (declaim (inline node-stack-allocate-p))
381 (defun node-stack-allocate-p (node)
382 (awhen (node-lvar node)
383 (lvar-dynamic-extent it)))
385 (defun use-good-for-dx-p (use)
386 (and (combination-p use)
387 (eq (combination-kind use) :known)
388 (awhen (fun-info-stack-allocate-result
389 (combination-fun-info use))
392 (declaim (inline block-to-be-deleted-p))
393 (defun block-to-be-deleted-p (block)
394 (or (block-delete-p block)
395 (eq (functional-kind (block-home-lambda block)) :deleted)))
397 ;;; Checks whether NODE is in a block to be deleted
398 (declaim (inline node-to-be-deleted-p))
399 (defun node-to-be-deleted-p (node)
400 (block-to-be-deleted-p (node-block node)))
402 (declaim (ftype (sfunction (clambda) cblock) lambda-block))
403 (defun lambda-block (clambda)
404 (node-block (lambda-bind clambda)))
405 (declaim (ftype (sfunction (clambda) component) lambda-component))
406 (defun lambda-component (clambda)
407 (block-component (lambda-block clambda)))
409 (declaim (ftype (sfunction (cblock) node) block-start-node))
410 (defun block-start-node (block)
411 (ctran-next (block-start block)))
413 ;;; Return the enclosing cleanup for environment of the first or last
415 (defun block-start-cleanup (block)
416 (node-enclosing-cleanup (block-start-node block)))
417 (defun block-end-cleanup (block)
418 (node-enclosing-cleanup (block-last block)))
420 ;;; Return the non-LET LAMBDA that holds BLOCK's code, or NIL
421 ;;; if there is none.
423 ;;; There can legitimately be no home lambda in dead code early in the
424 ;;; IR1 conversion process, e.g. when IR1-converting the SETQ form in
425 ;;; (BLOCK B (RETURN-FROM B) (SETQ X 3))
426 ;;; where the block is just a placeholder during parsing and doesn't
427 ;;; actually correspond to code which will be written anywhere.
428 (declaim (ftype (sfunction (cblock) (or clambda null)) block-home-lambda-or-null))
429 (defun block-home-lambda-or-null (block)
430 (if (node-p (block-last block))
431 ;; This is the old CMU CL way of doing it.
432 (node-home-lambda (block-last block))
433 ;; Now that SBCL uses this operation more aggressively than CMU
434 ;; CL did, the old CMU CL way of doing it can fail in two ways.
435 ;; 1. It can fail in a few cases even when a meaningful home
436 ;; lambda exists, e.g. in IR1-CONVERT of one of the legs of
438 ;; 2. It can fail when converting a form which is born orphaned
439 ;; so that it never had a meaningful home lambda, e.g. a form
440 ;; which follows a RETURN-FROM or GO form.
441 (let ((pred-list (block-pred block)))
442 ;; To deal with case 1, we reason that
443 ;; previous-in-target-execution-order blocks should be in the
444 ;; same lambda, and that they seem in practice to be
445 ;; previous-in-compilation-order blocks too, so we look back
446 ;; to find one which is sufficiently initialized to tell us
447 ;; what the home lambda is.
449 ;; We could get fancy about this, flooding through the
450 ;; graph of all the previous blocks, but in practice it
451 ;; seems to work just to grab the first previous block and
453 (node-home-lambda (block-last (first pred-list)))
454 ;; In case 2, we end up with an empty PRED-LIST and
455 ;; have to punt: There's no home lambda.
458 ;;; Return the non-LET LAMBDA that holds BLOCK's code.
459 (declaim (ftype (sfunction (cblock) clambda) block-home-lambda))
460 (defun block-home-lambda (block)
461 (block-home-lambda-or-null block))
463 ;;; Return the IR1 physical environment for BLOCK.
464 (declaim (ftype (sfunction (cblock) physenv) block-physenv))
465 (defun block-physenv (block)
466 (lambda-physenv (block-home-lambda block)))
468 ;;; Return the Top Level Form number of PATH, i.e. the ordinal number
469 ;;; of its original source's top level form in its compilation unit.
470 (defun source-path-tlf-number (path)
471 (declare (list path))
474 ;;; Return the (reversed) list for the PATH in the original source
475 ;;; (with the Top Level Form number last).
476 (defun source-path-original-source (path)
477 (declare (list path) (inline member))
478 (cddr (member 'original-source-start path :test #'eq)))
480 ;;; Return the Form Number of PATH's original source inside the Top
481 ;;; Level Form that contains it. This is determined by the order that
482 ;;; we walk the subforms of the top level source form.
483 (defun source-path-form-number (path)
484 (declare (list path) (inline member))
485 (cadr (member 'original-source-start path :test #'eq)))
487 ;;; Return a list of all the enclosing forms not in the original
488 ;;; source that converted to get to this form, with the immediate
489 ;;; source for node at the start of the list.
490 (defun source-path-forms (path)
491 (subseq path 0 (position 'original-source-start path)))
493 ;;; Return the innermost source form for NODE.
494 (defun node-source-form (node)
495 (declare (type node node))
496 (let* ((path (node-source-path node))
497 (forms (source-path-forms path)))
500 (values (find-original-source path)))))
502 ;;; Return NODE-SOURCE-FORM, T if lvar has a single use, otherwise
504 (defun lvar-source (lvar)
505 (let ((use (lvar-uses lvar)))
508 (values (node-source-form use) t))))
510 ;;; Return the unique node, delivering a value to LVAR.
511 #!-sb-fluid (declaim (inline lvar-use))
512 (defun lvar-use (lvar)
513 (the (not list) (lvar-uses lvar)))
515 #!-sb-fluid (declaim (inline lvar-has-single-use-p))
516 (defun lvar-has-single-use-p (lvar)
517 (typep (lvar-uses lvar) '(not list)))
519 ;;; Return the LAMBDA that is CTRAN's home, or NIL if there is none.
520 (declaim (ftype (sfunction (ctran) (or clambda null))
521 ctran-home-lambda-or-null))
522 (defun ctran-home-lambda-or-null (ctran)
523 ;; KLUDGE: This function is a post-CMU-CL hack by WHN, and this
524 ;; implementation might not be quite right, or might be uglier than
525 ;; necessary. It appears that the original Python never found a need
526 ;; to do this operation. The obvious things based on
527 ;; NODE-HOME-LAMBDA of CTRAN-USE usually work; then if that fails,
528 ;; BLOCK-HOME-LAMBDA of CTRAN-BLOCK works, given that we
529 ;; generalize it enough to grovel harder when the simple CMU CL
530 ;; approach fails, and furthermore realize that in some exceptional
531 ;; cases it might return NIL. -- WHN 2001-12-04
532 (cond ((ctran-use ctran)
533 (node-home-lambda (ctran-use ctran)))
535 (block-home-lambda-or-null (ctran-block ctran)))
537 (bug "confused about home lambda for ~S" ctran))))
539 ;;; Return the LAMBDA that is CTRAN's home.
540 (declaim (ftype (sfunction (ctran) clambda) ctran-home-lambda))
541 (defun ctran-home-lambda (ctran)
542 (ctran-home-lambda-or-null ctran))
544 (declaim (inline cast-single-value-p))
545 (defun cast-single-value-p (cast)
546 (not (values-type-p (cast-asserted-type cast))))
548 #!-sb-fluid (declaim (inline lvar-single-value-p))
549 (defun lvar-single-value-p (lvar)
551 (let ((dest (lvar-dest lvar)))
556 (eq (basic-combination-fun dest) lvar))
559 (declare (notinline lvar-single-value-p))
560 (and (cast-single-value-p dest)
561 (lvar-single-value-p (node-lvar dest)))))
565 (defun principal-lvar-end (lvar)
566 (loop for prev = lvar then (node-lvar dest)
567 for dest = (and prev (lvar-dest prev))
569 finally (return (values dest prev))))
571 (defun principal-lvar-single-valuify (lvar)
572 (loop for prev = lvar then (node-lvar dest)
573 for dest = (and prev (lvar-dest prev))
575 do (setf (node-derived-type dest)
576 (make-short-values-type (list (single-value-type
577 (node-derived-type dest)))))
578 (reoptimize-lvar prev)))
580 ;;; Return a new LEXENV just like DEFAULT except for the specified
581 ;;; slot values. Values for the alist slots are NCONCed to the
582 ;;; beginning of the current value, rather than replacing it entirely.
583 (defun make-lexenv (&key (default *lexenv*)
584 funs vars blocks tags
586 (lambda (lexenv-lambda default))
587 (cleanup (lexenv-cleanup default))
588 (handled-conditions (lexenv-handled-conditions default))
589 (disabled-package-locks
590 (lexenv-disabled-package-locks default))
591 (policy (lexenv-policy default)))
592 (macrolet ((frob (var slot)
593 `(let ((old (,slot default)))
597 (internal-make-lexenv
598 (frob funs lexenv-funs)
599 (frob vars lexenv-vars)
600 (frob blocks lexenv-blocks)
601 (frob tags lexenv-tags)
602 (frob type-restrictions lexenv-type-restrictions)
603 lambda cleanup handled-conditions
604 disabled-package-locks policy)))
606 ;;; Makes a LEXENV, suitable for using in a MACROLET introduced
608 (defun make-restricted-lexenv (lexenv)
609 (flet ((fun-good-p (fun)
610 (destructuring-bind (name . thing) fun
611 (declare (ignore name))
615 (cons (aver (eq (car thing) 'macro))
618 (destructuring-bind (name . thing) var
619 (declare (ignore name))
621 ;; The evaluator will mark lexicals with :BOGUS when it
622 ;; translates an interpreter lexenv to a compiler
624 ((or leaf #!+sb-eval (member :bogus)) nil)
625 (cons (aver (eq (car thing) 'macro))
627 (heap-alien-info nil)))))
628 (internal-make-lexenv
629 (remove-if-not #'fun-good-p (lexenv-funs lexenv))
630 (remove-if-not #'var-good-p (lexenv-vars lexenv))
633 (lexenv-type-restrictions lexenv) ; XXX
636 (lexenv-handled-conditions lexenv)
637 (lexenv-disabled-package-locks lexenv)
638 (lexenv-policy lexenv))))
640 ;;;; flow/DFO/component hackery
642 ;;; Join BLOCK1 and BLOCK2.
643 (defun link-blocks (block1 block2)
644 (declare (type cblock block1 block2))
645 (setf (block-succ block1)
646 (if (block-succ block1)
647 (%link-blocks block1 block2)
649 (push block1 (block-pred block2))
651 (defun %link-blocks (block1 block2)
652 (declare (type cblock block1 block2))
653 (let ((succ1 (block-succ block1)))
654 (aver (not (memq block2 succ1)))
655 (cons block2 succ1)))
657 ;;; This is like LINK-BLOCKS, but we separate BLOCK1 and BLOCK2. If
658 ;;; this leaves a successor with a single predecessor that ends in an
659 ;;; IF, then set BLOCK-TEST-MODIFIED so that any test constraint will
660 ;;; now be able to be propagated to the successor.
661 (defun unlink-blocks (block1 block2)
662 (declare (type cblock block1 block2))
663 (let ((succ1 (block-succ block1)))
664 (if (eq block2 (car succ1))
665 (setf (block-succ block1) (cdr succ1))
666 (do ((succ (cdr succ1) (cdr succ))
668 ((eq (car succ) block2)
669 (setf (cdr prev) (cdr succ)))
672 (let ((new-pred (delq block1 (block-pred block2))))
673 (setf (block-pred block2) new-pred)
674 (when (singleton-p new-pred)
675 (let ((pred-block (first new-pred)))
676 (when (if-p (block-last pred-block))
677 (setf (block-test-modified pred-block) t)))))
680 ;;; Swing the succ/pred link between BLOCK and OLD to be between BLOCK
681 ;;; and NEW. If BLOCK ends in an IF, then we have to fix up the
682 ;;; consequent/alternative blocks to point to NEW. We also set
683 ;;; BLOCK-TEST-MODIFIED so that any test constraint will be applied to
684 ;;; the new successor.
685 (defun change-block-successor (block old new)
686 (declare (type cblock new old block))
687 (unlink-blocks block old)
688 (let ((last (block-last block))
689 (comp (block-component block)))
690 (setf (component-reanalyze comp) t)
693 (setf (block-test-modified block) t)
694 (let* ((succ-left (block-succ block))
695 (new (if (and (eq new (component-tail comp))
699 (unless (memq new succ-left)
700 (link-blocks block new))
701 (macrolet ((frob (slot)
702 `(when (eq (,slot last) old)
703 (setf (,slot last) new))))
705 (frob if-alternative)
706 (when (eq (if-consequent last)
707 (if-alternative last))
708 (reoptimize-component (block-component block) :maybe)))))
710 (unless (memq new (block-succ block))
711 (link-blocks block new)))))
715 ;;; Unlink a block from the next/prev chain. We also null out the
717 (declaim (ftype (sfunction (cblock) (values)) remove-from-dfo))
718 (defun remove-from-dfo (block)
719 (let ((next (block-next block))
720 (prev (block-prev block)))
721 (setf (block-component block) nil)
722 (setf (block-next prev) next)
723 (setf (block-prev next) prev))
726 ;;; Add BLOCK to the next/prev chain following AFTER. We also set the
727 ;;; COMPONENT to be the same as for AFTER.
728 (defun add-to-dfo (block after)
729 (declare (type cblock block after))
730 (let ((next (block-next after))
731 (comp (block-component after)))
732 (aver (not (eq (component-kind comp) :deleted)))
733 (setf (block-component block) comp)
734 (setf (block-next after) block)
735 (setf (block-prev block) after)
736 (setf (block-next block) next)
737 (setf (block-prev next) block))
740 ;;; List all NLX-INFOs which BLOCK can exit to.
742 ;;; We hope that no cleanup actions are performed in the middle of
743 ;;; BLOCK, so it is enough to look only at cleanups in the block
744 ;;; end. The tricky thing is a special cleanup block; all its nodes
745 ;;; have the same cleanup info, corresponding to the start, so the
746 ;;; same approach returns safe result.
747 (defun map-block-nlxes (fun block &optional dx-cleanup-fun)
748 (loop for cleanup = (block-end-cleanup block)
749 then (node-enclosing-cleanup (cleanup-mess-up cleanup))
751 do (let ((mess-up (cleanup-mess-up cleanup)))
752 (case (cleanup-kind cleanup)
754 (aver (entry-p mess-up))
755 (loop for exit in (entry-exits mess-up)
756 for nlx-info = (exit-nlx-info exit)
757 do (funcall fun nlx-info)))
758 ((:catch :unwind-protect)
759 (aver (combination-p mess-up))
760 (let* ((arg-lvar (first (basic-combination-args mess-up)))
761 (nlx-info (constant-value (ref-leaf (lvar-use arg-lvar)))))
762 (funcall fun nlx-info)))
765 (funcall dx-cleanup-fun cleanup)))))))
767 ;;; Set the FLAG for all the blocks in COMPONENT to NIL, except for
768 ;;; the head and tail which are set to T.
769 (declaim (ftype (sfunction (component) (values)) clear-flags))
770 (defun clear-flags (component)
771 (let ((head (component-head component))
772 (tail (component-tail component)))
773 (setf (block-flag head) t)
774 (setf (block-flag tail) t)
775 (do-blocks (block component)
776 (setf (block-flag block) nil)))
779 ;;; Make a component with no blocks in it. The BLOCK-FLAG is initially
780 ;;; true in the head and tail blocks.
781 (declaim (ftype (sfunction () component) make-empty-component))
782 (defun make-empty-component ()
783 (let* ((head (make-block-key :start nil :component nil))
784 (tail (make-block-key :start nil :component nil))
785 (res (make-component head tail)))
786 (setf (block-flag head) t)
787 (setf (block-flag tail) t)
788 (setf (block-component head) res)
789 (setf (block-component tail) res)
790 (setf (block-next head) tail)
791 (setf (block-prev tail) head)
794 ;;; Make NODE the LAST node in its block, splitting the block if necessary.
795 ;;; The new block is added to the DFO immediately following NODE's block.
796 (defun node-ends-block (node)
797 (declare (type node node))
798 (let* ((block (node-block node))
799 (start (node-next node))
800 (last (block-last block)))
801 (unless (eq last node)
802 (aver (and (eq (ctran-kind start) :inside-block)
803 (not (block-delete-p block))))
804 (let* ((succ (block-succ block))
806 (make-block-key :start start
807 :component (block-component block)
808 :succ succ :last last)))
809 (setf (ctran-kind start) :block-start)
810 (setf (ctran-use start) nil)
811 (setf (block-last block) node)
812 (setf (node-next node) nil)
815 (cons new-block (remove block (block-pred b)))))
816 (setf (block-succ block) ())
817 (link-blocks block new-block)
818 (add-to-dfo new-block block)
819 (setf (component-reanalyze (block-component block)) t)
821 (do ((ctran start (node-next (ctran-next ctran))))
823 (setf (ctran-block ctran) new-block))
825 (setf (block-type-asserted block) t)
826 (setf (block-test-modified block) t))))
831 ;;; Deal with deleting the last (read) reference to a LAMBDA-VAR.
832 (defun delete-lambda-var (leaf)
833 (declare (type lambda-var leaf))
835 ;; Iterate over all local calls flushing the corresponding argument,
836 ;; allowing the computation of the argument to be deleted. We also
837 ;; mark the LET for reoptimization, since it may be that we have
838 ;; deleted its last variable.
839 (let* ((fun (lambda-var-home leaf))
840 (n (position leaf (lambda-vars fun))))
841 (dolist (ref (leaf-refs fun))
842 (let* ((lvar (node-lvar ref))
843 (dest (and lvar (lvar-dest lvar))))
844 (when (and (combination-p dest)
845 (eq (basic-combination-fun dest) lvar)
846 (eq (basic-combination-kind dest) :local))
847 (let* ((args (basic-combination-args dest))
849 (reoptimize-lvar arg)
851 (setf (elt args n) nil))))))
853 ;; The LAMBDA-VAR may still have some SETs, but this doesn't cause
854 ;; too much difficulty, since we can efficiently implement
855 ;; write-only variables. We iterate over the SETs, marking their
856 ;; blocks for dead code flushing, since we can delete SETs whose
858 (dolist (set (lambda-var-sets leaf))
859 (setf (block-flush-p (node-block set)) t))
863 ;;; Note that something interesting has happened to VAR.
864 (defun reoptimize-lambda-var (var)
865 (declare (type lambda-var var))
866 (let ((fun (lambda-var-home var)))
867 ;; We only deal with LET variables, marking the corresponding
868 ;; initial value arg as needing to be reoptimized.
869 (when (and (eq (functional-kind fun) :let)
871 (do ((args (basic-combination-args
872 (lvar-dest (node-lvar (first (leaf-refs fun)))))
874 (vars (lambda-vars fun) (cdr vars)))
876 (reoptimize-lvar (car args))))))
879 ;;; Delete a function that has no references. This need only be called
880 ;;; on functions that never had any references, since otherwise
881 ;;; DELETE-REF will handle the deletion.
882 (defun delete-functional (fun)
883 (aver (and (null (leaf-refs fun))
884 (not (functional-entry-fun fun))))
886 (optional-dispatch (delete-optional-dispatch fun))
887 (clambda (delete-lambda fun)))
890 ;;; Deal with deleting the last reference to a CLAMBDA, which means
891 ;;; that the lambda is unreachable, so that its body may be
892 ;;; deleted. We set FUNCTIONAL-KIND to :DELETED and rely on
893 ;;; IR1-OPTIMIZE to delete its blocks.
894 (defun delete-lambda (clambda)
895 (declare (type clambda clambda))
896 (let ((original-kind (functional-kind clambda))
897 (bind (lambda-bind clambda)))
898 (aver (not (member original-kind '(:deleted :toplevel))))
899 (aver (not (functional-has-external-references-p clambda)))
900 (aver (or (eq original-kind :zombie) bind))
901 (setf (functional-kind clambda) :deleted)
902 (setf (lambda-bind clambda) nil)
904 (labels ((delete-children (lambda)
905 (dolist (child (lambda-children lambda))
906 (cond ((eq (functional-kind child) :deleted)
907 (delete-children child))
909 (delete-lambda child))))
910 (setf (lambda-children lambda) nil)
911 (setf (lambda-parent lambda) nil)))
912 (delete-children clambda))
914 ;; (The IF test is (FUNCTIONAL-SOMEWHAT-LETLIKE-P CLAMBDA), except
915 ;; that we're using the old value of the KIND slot, not the
916 ;; current slot value, which has now been set to :DELETED.)
919 ((:let :mv-let :assignment)
920 (let ((bind-block (node-block bind)))
921 (mark-for-deletion bind-block))
922 (let ((home (lambda-home clambda)))
923 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
924 ;; KLUDGE: In presence of NLEs we cannot always understand that
925 ;; LET's BIND dominates its body [for a LET "its" body is not
926 ;; quite its]; let's delete too dangerous for IR2 stuff. --
928 (dolist (var (lambda-vars clambda))
929 (flet ((delete-node (node)
930 (mark-for-deletion (node-block node))))
931 (mapc #'delete-node (leaf-refs var))
932 (mapc #'delete-node (lambda-var-sets var)))))
934 ;; Function has no reachable references.
935 (dolist (ref (lambda-refs clambda))
936 (mark-for-deletion (node-block ref)))
937 ;; If the function isn't a LET, we unlink the function head
938 ;; and tail from the component head and tail to indicate that
939 ;; the code is unreachable. We also delete the function from
940 ;; COMPONENT-LAMBDAS (it won't be there before local call
941 ;; analysis, but no matter.) If the lambda was never
942 ;; referenced, we give a note.
943 (let* ((bind-block (node-block bind))
944 (component (block-component bind-block))
945 (return (lambda-return clambda))
946 (return-block (and return (node-block return))))
947 (unless (leaf-ever-used clambda)
948 (let ((*compiler-error-context* bind))
949 (compiler-notify 'code-deletion-note
950 :format-control "deleting unused function~:[.~;~:*~% ~S~]"
951 :format-arguments (list (leaf-debug-name clambda)))))
952 (unless (block-delete-p bind-block)
953 (unlink-blocks (component-head component) bind-block))
954 (when (and return-block (not (block-delete-p return-block)))
955 (mark-for-deletion return-block)
956 (unlink-blocks return-block (component-tail component)))
957 (setf (component-reanalyze component) t)
958 (let ((tails (lambda-tail-set clambda)))
959 (setf (tail-set-funs tails)
960 (delete clambda (tail-set-funs tails)))
961 (setf (lambda-tail-set clambda) nil))
962 (setf (component-lambdas component)
963 (delq clambda (component-lambdas component))))))
965 ;; If the lambda is an XEP, then we null out the ENTRY-FUN in its
966 ;; ENTRY-FUN so that people will know that it is not an entry
968 (when (eq original-kind :external)
969 (let ((fun (functional-entry-fun clambda)))
970 (setf (functional-entry-fun fun) nil)
971 (when (optional-dispatch-p fun)
972 (delete-optional-dispatch fun)))))
976 ;;; Deal with deleting the last reference to an OPTIONAL-DISPATCH. We
977 ;;; have to be a bit more careful than with lambdas, since DELETE-REF
978 ;;; is used both before and after local call analysis. Afterward, all
979 ;;; references to still-existing OPTIONAL-DISPATCHes have been moved
980 ;;; to the XEP, leaving it with no references at all. So we look at
981 ;;; the XEP to see whether an optional-dispatch is still really being
982 ;;; used. But before local call analysis, there are no XEPs, and all
983 ;;; references are direct.
985 ;;; When we do delete the OPTIONAL-DISPATCH, we grovel all of its
986 ;;; entry-points, making them be normal lambdas, and then deleting the
987 ;;; ones with no references. This deletes any e-p lambdas that were
988 ;;; either never referenced, or couldn't be deleted when the last
989 ;;; reference was deleted (due to their :OPTIONAL kind.)
991 ;;; Note that the last optional entry point may alias the main entry,
992 ;;; so when we process the main entry, its KIND may have been changed
993 ;;; to NIL or even converted to a LETlike value.
994 (defun delete-optional-dispatch (leaf)
995 (declare (type optional-dispatch leaf))
996 (let ((entry (functional-entry-fun leaf)))
997 (unless (and entry (leaf-refs entry))
998 (aver (or (not entry) (eq (functional-kind entry) :deleted)))
999 (setf (functional-kind leaf) :deleted)
1002 (unless (eq (functional-kind fun) :deleted)
1003 (aver (eq (functional-kind fun) :optional))
1004 (setf (functional-kind fun) nil)
1005 (let ((refs (leaf-refs fun)))
1007 (delete-lambda fun))
1009 (or (maybe-let-convert fun)
1010 (maybe-convert-to-assignment fun)))
1012 (maybe-convert-to-assignment fun)))))))
1014 (dolist (ep (optional-dispatch-entry-points leaf))
1015 (when (promise-ready-p ep)
1017 (when (optional-dispatch-more-entry leaf)
1018 (frob (optional-dispatch-more-entry leaf)))
1019 (let ((main (optional-dispatch-main-entry leaf)))
1021 (setf (functional-entry-fun entry) main)
1022 (setf (functional-entry-fun main) entry))
1023 (when (eq (functional-kind main) :optional)
1028 (defun note-local-functional (fun)
1029 (declare (type functional fun))
1030 (when (and (leaf-has-source-name-p fun)
1031 (eq (leaf-source-name fun) (functional-debug-name fun)))
1032 (let ((name (leaf-source-name fun)))
1033 (let ((defined-fun (gethash name *free-funs*)))
1034 (when (and defined-fun
1035 (defined-fun-p defined-fun)
1036 (eq (defined-fun-functional defined-fun) fun))
1037 (remhash name *free-funs*))))))
1039 ;;; Do stuff to delete the semantic attachments of a REF node. When
1040 ;;; this leaves zero or one reference, we do a type dispatch off of
1041 ;;; the leaf to determine if a special action is appropriate.
1042 (defun delete-ref (ref)
1043 (declare (type ref ref))
1044 (let* ((leaf (ref-leaf ref))
1045 (refs (delq ref (leaf-refs leaf))))
1046 (setf (leaf-refs leaf) refs)
1051 (delete-lambda-var leaf))
1053 (ecase (functional-kind leaf)
1054 ((nil :let :mv-let :assignment :escape :cleanup)
1055 (aver (null (functional-entry-fun leaf)))
1056 (delete-lambda leaf))
1058 (delete-lambda leaf))
1059 ((:deleted :zombie :optional))))
1061 (unless (eq (functional-kind leaf) :deleted)
1062 (delete-optional-dispatch leaf)))))
1065 (clambda (or (maybe-let-convert leaf)
1066 (maybe-convert-to-assignment leaf)))
1067 (lambda-var (reoptimize-lambda-var leaf))))
1070 (clambda (maybe-convert-to-assignment leaf))))))
1074 ;;; This function is called by people who delete nodes; it provides a
1075 ;;; way to indicate that the value of a lvar is no longer used. We
1076 ;;; null out the LVAR-DEST, set FLUSH-P in the blocks containing uses
1077 ;;; of LVAR and set COMPONENT-REOPTIMIZE.
1078 (defun flush-dest (lvar)
1079 (declare (type (or lvar null) lvar))
1081 (setf (lvar-dest lvar) nil)
1082 (flush-lvar-externally-checkable-type lvar)
1084 (let ((prev (node-prev use)))
1085 (let ((block (ctran-block prev)))
1086 (reoptimize-component (block-component block) t)
1087 (setf (block-attributep (block-flags block)
1088 flush-p type-asserted type-check)
1090 (setf (node-lvar use) nil))
1091 (setf (lvar-uses lvar) nil))
1094 (defun delete-dest (lvar)
1096 (let* ((dest (lvar-dest lvar))
1097 (prev (node-prev dest)))
1098 (let ((block (ctran-block prev)))
1099 (unless (block-delete-p block)
1100 (mark-for-deletion block))))))
1102 ;;; Queue the block for deletion
1103 (defun delete-block-lazily (block)
1104 (declare (type cblock block))
1105 (unless (block-delete-p block)
1106 (setf (block-delete-p block) t)
1107 (push block (component-delete-blocks (block-component block)))))
1109 ;;; Do a graph walk backward from BLOCK, marking all predecessor
1110 ;;; blocks with the DELETE-P flag.
1111 (defun mark-for-deletion (block)
1112 (declare (type cblock block))
1113 (let* ((component (block-component block))
1114 (head (component-head component)))
1115 (labels ((helper (block)
1116 (delete-block-lazily block)
1117 (dolist (pred (block-pred block))
1118 (unless (or (block-delete-p pred)
1121 (unless (block-delete-p block)
1123 (setf (component-reanalyze component) t))))
1126 ;;; This function does what is necessary to eliminate the code in it
1127 ;;; from the IR1 representation. This involves unlinking it from its
1128 ;;; predecessors and successors and deleting various node-specific
1129 ;;; semantic information. BLOCK must be already removed from
1130 ;;; COMPONENT-DELETE-BLOCKS.
1131 (defun delete-block (block &optional silent)
1132 (declare (type cblock block))
1133 (aver (block-component block)) ; else block is already deleted!
1134 #!+high-security (aver (not (memq block (component-delete-blocks (block-component block)))))
1136 (note-block-deletion block))
1137 (setf (block-delete-p block) t)
1139 (dolist (b (block-pred block))
1140 (unlink-blocks b block)
1141 ;; In bug 147 the almost-all-blocks-have-a-successor invariant was
1142 ;; broken when successors were deleted without setting the
1143 ;; BLOCK-DELETE-P flags of their predececessors. Make sure that
1144 ;; doesn't happen again.
1145 (aver (not (and (null (block-succ b))
1146 (not (block-delete-p b))
1147 (not (eq b (component-head (block-component b))))))))
1148 (dolist (b (block-succ block))
1149 (unlink-blocks block b))
1151 (do-nodes-carefully (node block)
1152 (when (valued-node-p node)
1153 (delete-lvar-use node))
1155 (ref (delete-ref node))
1156 (cif (flush-dest (if-test node)))
1157 ;; The next two cases serve to maintain the invariant that a LET
1158 ;; always has a well-formed COMBINATION, REF and BIND. We delete
1159 ;; the lambda whenever we delete any of these, but we must be
1160 ;; careful that this LET has not already been partially deleted.
1162 (when (and (eq (basic-combination-kind node) :local)
1163 ;; Guards COMBINATION-LAMBDA agains the REF being deleted.
1164 (lvar-uses (basic-combination-fun node)))
1165 (let ((fun (combination-lambda node)))
1166 ;; If our REF was the second-to-last ref, and has been
1167 ;; deleted, then FUN may be a LET for some other
1169 (when (and (functional-letlike-p fun)
1170 (eq (let-combination fun) node))
1171 (delete-lambda fun))))
1172 (flush-dest (basic-combination-fun node))
1173 (dolist (arg (basic-combination-args node))
1174 (when arg (flush-dest arg))))
1176 (let ((lambda (bind-lambda node)))
1177 (unless (eq (functional-kind lambda) :deleted)
1178 (delete-lambda lambda))))
1180 (let ((value (exit-value node))
1181 (entry (exit-entry node)))
1185 (setf (entry-exits entry)
1186 (delq node (entry-exits entry))))))
1188 (dolist (exit (entry-exits node))
1189 (mark-for-deletion (node-block exit)))
1190 (let ((home (node-home-lambda node)))
1191 (setf (lambda-entries home) (delq node (lambda-entries home)))))
1193 (flush-dest (return-result node))
1194 (delete-return node))
1196 (flush-dest (set-value node))
1197 (let ((var (set-var node)))
1198 (setf (basic-var-sets var)
1199 (delete node (basic-var-sets var)))))
1201 (flush-dest (cast-value node)))))
1203 (remove-from-dfo block)
1206 ;;; Do stuff to indicate that the return node NODE is being deleted.
1207 (defun delete-return (node)
1208 (declare (type creturn node))
1209 (let* ((fun (return-lambda node))
1210 (tail-set (lambda-tail-set fun)))
1211 (aver (lambda-return fun))
1212 (setf (lambda-return fun) nil)
1213 (when (and tail-set (not (find-if #'lambda-return
1214 (tail-set-funs tail-set))))
1215 (setf (tail-set-type tail-set) *empty-type*)))
1218 ;;; If any of the VARS in FUN was never referenced and was not
1219 ;;; declared IGNORE, then complain.
1220 (defun note-unreferenced-vars (fun)
1221 (declare (type clambda fun))
1222 (dolist (var (lambda-vars fun))
1223 (unless (or (leaf-ever-used var)
1224 (lambda-var-ignorep var))
1225 (let ((*compiler-error-context* (lambda-bind fun)))
1226 (unless (policy *compiler-error-context* (= inhibit-warnings 3))
1227 ;; ANSI section "3.2.5 Exceptional Situations in the Compiler"
1228 ;; requires this to be no more than a STYLE-WARNING.
1230 (compiler-style-warn "The variable ~S is defined but never used."
1231 (leaf-debug-name var))
1232 ;; There's no reason to accept this kind of equivocation
1233 ;; when compiling our own code, though.
1235 (warn "The variable ~S is defined but never used."
1236 (leaf-debug-name var)))
1237 (setf (leaf-ever-used var) t)))) ; to avoid repeated warnings? -- WHN
1240 (defvar *deletion-ignored-objects* '(t nil))
1242 ;;; Return true if we can find OBJ in FORM, NIL otherwise. We bound
1243 ;;; our recursion so that we don't get lost in circular structures. We
1244 ;;; ignore the car of forms if they are a symbol (to prevent confusing
1245 ;;; function referencess with variables), and we also ignore anything
1247 (defun present-in-form (obj form depth)
1248 (declare (type (integer 0 20) depth))
1249 (cond ((= depth 20) nil)
1253 (let ((first (car form))
1255 (if (member first '(quote function))
1257 (or (and (not (symbolp first))
1258 (present-in-form obj first depth))
1259 (do ((l (cdr form) (cdr l))
1261 ((or (atom l) (> n 100))
1263 (declare (fixnum n))
1264 (when (present-in-form obj (car l) depth)
1267 ;;; This function is called on a block immediately before we delete
1268 ;;; it. We check to see whether any of the code about to die appeared
1269 ;;; in the original source, and emit a note if so.
1271 ;;; If the block was in a lambda is now deleted, then we ignore the
1272 ;;; whole block, since this case is picked off in DELETE-LAMBDA. We
1273 ;;; also ignore the deletion of CRETURN nodes, since it is somewhat
1274 ;;; reasonable for a function to not return, and there is a different
1275 ;;; note for that case anyway.
1277 ;;; If the actual source is an atom, then we use a bunch of heuristics
1278 ;;; to guess whether this reference really appeared in the original
1280 ;;; -- If a symbol, it must be interned and not a keyword.
1281 ;;; -- It must not be an easily introduced constant (T or NIL, a fixnum
1282 ;;; or a character.)
1283 ;;; -- The atom must be "present" in the original source form, and
1284 ;;; present in all intervening actual source forms.
1285 (defun note-block-deletion (block)
1286 (let ((home (block-home-lambda block)))
1287 (unless (eq (functional-kind home) :deleted)
1288 (do-nodes (node nil block)
1289 (let* ((path (node-source-path node))
1290 (first (first path)))
1291 (when (or (eq first 'original-source-start)
1293 (or (not (symbolp first))
1294 (let ((pkg (symbol-package first)))
1296 (not (eq pkg (symbol-package :end))))))
1297 (not (member first *deletion-ignored-objects*))
1298 (not (typep first '(or fixnum character)))
1300 (present-in-form first x 0))
1301 (source-path-forms path))
1302 (present-in-form first (find-original-source path)
1304 (unless (return-p node)
1305 (let ((*compiler-error-context* node))
1306 (compiler-notify 'code-deletion-note
1307 :format-control "deleting unreachable code"
1308 :format-arguments nil)))
1312 ;;; Delete a node from a block, deleting the block if there are no
1313 ;;; nodes left. We remove the node from the uses of its LVAR.
1315 ;;; If the node is the last node, there must be exactly one successor.
1316 ;;; We link all of our precedessors to the successor and unlink the
1317 ;;; block. In this case, we return T, otherwise NIL. If no nodes are
1318 ;;; left, and the block is a successor of itself, then we replace the
1319 ;;; only node with a degenerate exit node. This provides a way to
1320 ;;; represent the bodyless infinite loop, given the prohibition on
1321 ;;; empty blocks in IR1.
1322 (defun unlink-node (node)
1323 (declare (type node node))
1324 (when (valued-node-p node)
1325 (delete-lvar-use node))
1327 (let* ((ctran (node-next node))
1328 (next (and ctran (ctran-next ctran)))
1329 (prev (node-prev node))
1330 (block (ctran-block prev))
1331 (prev-kind (ctran-kind prev))
1332 (last (block-last block)))
1334 (setf (block-type-asserted block) t)
1335 (setf (block-test-modified block) t)
1337 (cond ((or (eq prev-kind :inside-block)
1338 (and (eq prev-kind :block-start)
1339 (not (eq node last))))
1340 (cond ((eq node last)
1341 (setf (block-last block) (ctran-use prev))
1342 (setf (node-next (ctran-use prev)) nil))
1344 (setf (ctran-next prev) next)
1345 (setf (node-prev next) prev)
1346 (when (if-p next) ; AOP wanted
1347 (reoptimize-lvar (if-test next)))))
1348 (setf (node-prev node) nil)
1351 (aver (eq prev-kind :block-start))
1352 (aver (eq node last))
1353 (let* ((succ (block-succ block))
1354 (next (first succ)))
1355 (aver (singleton-p succ))
1357 ((eq block (first succ))
1358 (with-ir1-environment-from-node node
1359 (let ((exit (make-exit)))
1360 (setf (ctran-next prev) nil)
1361 (link-node-to-previous-ctran exit prev)
1362 (setf (block-last block) exit)))
1363 (setf (node-prev node) nil)
1366 (aver (eq (block-start-cleanup block)
1367 (block-end-cleanup block)))
1368 (unlink-blocks block next)
1369 (dolist (pred (block-pred block))
1370 (change-block-successor pred block next))
1371 (when (block-delete-p block)
1372 (let ((component (block-component block)))
1373 (setf (component-delete-blocks component)
1374 (delq block (component-delete-blocks component)))))
1375 (remove-from-dfo block)
1376 (setf (block-delete-p block) t)
1377 (setf (node-prev node) nil)
1380 ;;; Return true if CTRAN has been deleted, false if it is still a valid
1382 (defun ctran-deleted-p (ctran)
1383 (declare (type ctran ctran))
1384 (let ((block (ctran-block ctran)))
1385 (or (not (block-component block))
1386 (block-delete-p block))))
1388 ;;; Return true if NODE has been deleted, false if it is still a valid
1390 (defun node-deleted (node)
1391 (declare (type node node))
1392 (let ((prev (node-prev node)))
1394 (ctran-deleted-p prev))))
1396 ;;; Delete all the blocks and functions in COMPONENT. We scan first
1397 ;;; marking the blocks as DELETE-P to prevent weird stuff from being
1398 ;;; triggered by deletion.
1399 (defun delete-component (component)
1400 (declare (type component component))
1401 (aver (null (component-new-functionals component)))
1402 (setf (component-kind component) :deleted)
1403 (do-blocks (block component)
1404 (delete-block-lazily block))
1405 (dolist (fun (component-lambdas component))
1406 (unless (eq (functional-kind fun) :deleted)
1407 (setf (functional-kind fun) nil)
1408 (setf (functional-entry-fun fun) nil)
1409 (setf (leaf-refs fun) nil)
1410 (delete-functional fun)))
1411 (clean-component component)
1414 ;;; Remove all pending blocks to be deleted. Return the nearest live
1415 ;;; block after or equal to BLOCK.
1416 (defun clean-component (component &optional block)
1417 (loop while (component-delete-blocks component)
1418 ;; actual deletion of a block may queue new blocks
1419 do (let ((current (pop (component-delete-blocks component))))
1420 (when (eq block current)
1421 (setq block (block-next block)))
1422 (delete-block current)))
1425 ;;; Convert code of the form
1426 ;;; (FOO ... (FUN ...) ...)
1428 ;;; (FOO ... ... ...).
1429 ;;; In other words, replace the function combination FUN by its
1430 ;;; arguments. If there are any problems with doing this, use GIVE-UP
1431 ;;; to blow out of whatever transform called this. Note, as the number
1432 ;;; of arguments changes, the transform must be prepared to return a
1433 ;;; lambda with a new lambda-list with the correct number of
1435 (defun splice-fun-args (lvar fun num-args)
1437 "If LVAR is a call to FUN with NUM-ARGS args, change those arguments
1438 to feed directly to the LVAR-DEST of LVAR, which must be a
1440 (declare (type lvar lvar)
1442 (type index num-args))
1443 (let ((outside (lvar-dest lvar))
1444 (inside (lvar-uses lvar)))
1445 (aver (combination-p outside))
1446 (unless (combination-p inside)
1447 (give-up-ir1-transform))
1448 (let ((inside-fun (combination-fun inside)))
1449 (unless (eq (lvar-fun-name inside-fun) fun)
1450 (give-up-ir1-transform))
1451 (let ((inside-args (combination-args inside)))
1452 (unless (= (length inside-args) num-args)
1453 (give-up-ir1-transform))
1454 (let* ((outside-args (combination-args outside))
1455 (arg-position (position lvar outside-args))
1456 (before-args (subseq outside-args 0 arg-position))
1457 (after-args (subseq outside-args (1+ arg-position))))
1458 (dolist (arg inside-args)
1459 (setf (lvar-dest arg) outside)
1460 (flush-lvar-externally-checkable-type arg))
1461 (setf (combination-args inside) nil)
1462 (setf (combination-args outside)
1463 (append before-args inside-args after-args))
1464 (change-ref-leaf (lvar-uses inside-fun)
1465 (find-free-fun 'list "???"))
1466 (setf (combination-fun-info inside) (info :function :info 'list)
1467 (combination-kind inside) :known)
1468 (setf (node-derived-type inside) *wild-type*)
1472 (defun extract-fun-args (lvar fun num-args)
1473 (declare (type lvar lvar)
1474 (type (or symbol list) fun)
1475 (type index num-args))
1476 (let ((fun (if (listp fun) fun (list fun))))
1477 (let ((inside (lvar-uses lvar)))
1478 (unless (combination-p inside)
1479 (give-up-ir1-transform))
1480 (let ((inside-fun (combination-fun inside)))
1481 (unless (member (lvar-fun-name inside-fun) fun)
1482 (give-up-ir1-transform))
1483 (let ((inside-args (combination-args inside)))
1484 (unless (= (length inside-args) num-args)
1485 (give-up-ir1-transform))
1486 (values (lvar-fun-name inside-fun) inside-args))))))
1488 (defun flush-combination (combination)
1489 (declare (type combination combination))
1490 (flush-dest (combination-fun combination))
1491 (dolist (arg (combination-args combination))
1493 (unlink-node combination)
1499 ;;; Change the LEAF that a REF refers to.
1500 (defun change-ref-leaf (ref leaf)
1501 (declare (type ref ref) (type leaf leaf))
1502 (unless (eq (ref-leaf ref) leaf)
1503 (push ref (leaf-refs leaf))
1505 (setf (ref-leaf ref) leaf)
1506 (setf (leaf-ever-used leaf) t)
1507 (let* ((ltype (leaf-type leaf))
1508 (vltype (make-single-value-type ltype)))
1509 (if (let* ((lvar (node-lvar ref))
1510 (dest (and lvar (lvar-dest lvar))))
1511 (and (basic-combination-p dest)
1512 (eq lvar (basic-combination-fun dest))
1513 (csubtypep ltype (specifier-type 'function))))
1514 (setf (node-derived-type ref) vltype)
1515 (derive-node-type ref vltype)))
1516 (reoptimize-lvar (node-lvar ref)))
1519 ;;; Change all REFS for OLD-LEAF to NEW-LEAF.
1520 (defun substitute-leaf (new-leaf old-leaf)
1521 (declare (type leaf new-leaf old-leaf))
1522 (dolist (ref (leaf-refs old-leaf))
1523 (change-ref-leaf ref new-leaf))
1526 ;;; like SUBSITUTE-LEAF, only there is a predicate on the REF to tell
1527 ;;; whether to substitute
1528 (defun substitute-leaf-if (test new-leaf old-leaf)
1529 (declare (type leaf new-leaf old-leaf) (type function test))
1530 (dolist (ref (leaf-refs old-leaf))
1531 (when (funcall test ref)
1532 (change-ref-leaf ref new-leaf)))
1535 ;;; Return a LEAF which represents the specified constant object. If
1536 ;;; the object is not in *CONSTANTS*, then we create a new constant
1537 ;;; LEAF and enter it.
1538 (defun find-constant (object)
1540 ;; FIXME: What is the significance of this test? ("things
1541 ;; that are worth uniquifying"?)
1542 '(or symbol number character instance))
1543 (or (gethash object *constants*)
1544 (setf (gethash object *constants*)
1545 (make-constant :value object
1546 :%source-name '.anonymous.
1547 :type (ctype-of object)
1548 :where-from :defined)))
1549 (make-constant :value object
1550 :%source-name '.anonymous.
1551 :type (ctype-of object)
1552 :where-from :defined)))
1554 ;;; Return true if VAR would have to be closed over if environment
1555 ;;; analysis ran now (i.e. if there are any uses that have a different
1556 ;;; home lambda than VAR's home.)
1557 (defun closure-var-p (var)
1558 (declare (type lambda-var var))
1559 (let ((home (lambda-var-home var)))
1560 (cond ((eq (functional-kind home) :deleted)
1562 (t (let ((home (lambda-home home)))
1565 :key #'node-home-lambda
1567 (or (frob (leaf-refs var))
1568 (frob (basic-var-sets var)))))))))
1570 ;;; If there is a non-local exit noted in ENTRY's environment that
1571 ;;; exits to CONT in that entry, then return it, otherwise return NIL.
1572 (defun find-nlx-info (exit)
1573 (declare (type exit exit))
1574 (let* ((entry (exit-entry exit))
1575 (cleanup (entry-cleanup entry))
1576 (block (first (block-succ (node-block exit)))))
1577 (dolist (nlx (physenv-nlx-info (node-physenv entry)) nil)
1578 (when (and (eq (nlx-info-block nlx) block)
1579 (eq (nlx-info-cleanup nlx) cleanup))
1582 (defun nlx-info-lvar (nlx)
1583 (declare (type nlx-info nlx))
1584 (node-lvar (block-last (nlx-info-target nlx))))
1586 ;;;; functional hackery
1588 (declaim (ftype (sfunction (functional) clambda) main-entry))
1589 (defun main-entry (functional)
1590 (etypecase functional
1591 (clambda functional)
1593 (optional-dispatch-main-entry functional))))
1595 ;;; RETURN true if FUNCTIONAL is a thing that can be treated like
1596 ;;; MV-BIND when it appears in an MV-CALL. All fixed arguments must be
1597 ;;; optional with null default and no SUPPLIED-P. There must be a
1598 ;;; &REST arg with no references.
1599 (declaim (ftype (sfunction (functional) boolean) looks-like-an-mv-bind))
1600 (defun looks-like-an-mv-bind (functional)
1601 (and (optional-dispatch-p functional)
1602 (do ((arg (optional-dispatch-arglist functional) (cdr arg)))
1604 (let ((info (lambda-var-arg-info (car arg))))
1605 (unless info (return nil))
1606 (case (arg-info-kind info)
1608 (when (or (arg-info-supplied-p info) (arg-info-default info))
1611 (return (and (null (cdr arg)) (null (leaf-refs (car arg))))))
1615 ;;; Return true if function is an external entry point. This is true
1616 ;;; of normal XEPs (:EXTERNAL kind) and also of top level lambdas
1617 ;;; (:TOPLEVEL kind.)
1619 (declare (type functional fun))
1620 (not (null (member (functional-kind fun) '(:external :toplevel)))))
1622 ;;; If LVAR's only use is a non-notinline global function reference,
1623 ;;; then return the referenced symbol, otherwise NIL. If NOTINLINE-OK
1624 ;;; is true, then we don't care if the leaf is NOTINLINE.
1625 (defun lvar-fun-name (lvar &optional notinline-ok)
1626 (declare (type lvar lvar))
1627 (let ((use (lvar-uses lvar)))
1629 (let ((leaf (ref-leaf use)))
1630 (if (and (global-var-p leaf)
1631 (eq (global-var-kind leaf) :global-function)
1632 (or (not (defined-fun-p leaf))
1633 (not (eq (defined-fun-inlinep leaf) :notinline))
1635 (leaf-source-name leaf)
1639 ;;; Return the source name of a combination. (This is an idiom
1640 ;;; which was used in CMU CL. I gather it always works. -- WHN)
1641 (defun combination-fun-source-name (combination)
1642 (let ((ref (lvar-uses (combination-fun combination))))
1643 (leaf-source-name (ref-leaf ref))))
1645 ;;; Return the COMBINATION node that is the call to the LET FUN.
1646 (defun let-combination (fun)
1647 (declare (type clambda fun))
1648 (aver (functional-letlike-p fun))
1649 (lvar-dest (node-lvar (first (leaf-refs fun)))))
1651 ;;; Return the initial value lvar for a LET variable, or NIL if there
1653 (defun let-var-initial-value (var)
1654 (declare (type lambda-var var))
1655 (let ((fun (lambda-var-home var)))
1656 (elt (combination-args (let-combination fun))
1657 (position-or-lose var (lambda-vars fun)))))
1659 ;;; Return the LAMBDA that is called by the local CALL.
1660 (defun combination-lambda (call)
1661 (declare (type basic-combination call))
1662 (aver (eq (basic-combination-kind call) :local))
1663 (ref-leaf (lvar-uses (basic-combination-fun call))))
1665 (defvar *inline-expansion-limit* 200
1667 "an upper limit on the number of inline function calls that will be expanded
1668 in any given code object (single function or block compilation)")
1670 ;;; Check whether NODE's component has exceeded its inline expansion
1671 ;;; limit, and warn if so, returning NIL.
1672 (defun inline-expansion-ok (node)
1673 (let ((expanded (incf (component-inline-expansions
1675 (node-block node))))))
1676 (cond ((> expanded *inline-expansion-limit*) nil)
1677 ((= expanded *inline-expansion-limit*)
1678 ;; FIXME: If the objective is to stop the recursive
1679 ;; expansion of inline functions, wouldn't it be more
1680 ;; correct to look back through surrounding expansions
1681 ;; (which are, I think, stored in the *CURRENT-PATH*, and
1682 ;; possibly stored elsewhere too) and suppress expansion
1683 ;; and print this warning when the function being proposed
1684 ;; for inline expansion is found there? (I don't like the
1685 ;; arbitrary numerical limit in principle, and I think
1686 ;; it'll be a nuisance in practice if we ever want the
1687 ;; compiler to be able to use WITH-COMPILATION-UNIT on
1688 ;; arbitrarily huge blocks of code. -- WHN)
1689 (let ((*compiler-error-context* node))
1690 (compiler-notify "*INLINE-EXPANSION-LIMIT* (~W) was exceeded, ~
1691 probably trying to~% ~
1692 inline a recursive function."
1693 *inline-expansion-limit*))
1697 ;;; Make sure that FUNCTIONAL is not let-converted or deleted.
1698 (defun assure-functional-live-p (functional)
1699 (declare (type functional functional))
1701 ;; looks LET-converted
1702 (functional-somewhat-letlike-p functional)
1703 ;; It's possible for a LET-converted function to end up
1704 ;; deleted later. In that case, for the purposes of this
1705 ;; analysis, it is LET-converted: LET-converted functionals
1706 ;; are too badly trashed to expand them inline, and deleted
1707 ;; LET-converted functionals are even worse.
1708 (memq (functional-kind functional) '(:deleted :zombie))))
1709 (throw 'locall-already-let-converted functional)))
1711 (defun call-full-like-p (call)
1712 (declare (type combination call))
1713 (let ((kind (basic-combination-kind call)))
1715 (and (eq kind :known)
1716 (let ((info (basic-combination-fun-info call)))
1718 (not (fun-info-ir2-convert info))
1719 (dolist (template (fun-info-templates info) t)
1720 (when (eq (template-ltn-policy template) :fast-safe)
1721 (multiple-value-bind (val win)
1722 (valid-fun-use call (template-type template))
1723 (when (or val (not win)) (return nil)))))))))))
1727 ;;; Apply a function to some arguments, returning a list of the values
1728 ;;; resulting of the evaluation. If an error is signalled during the
1729 ;;; application, then we produce a warning message using WARN-FUN and
1730 ;;; return NIL as our second value to indicate this. NODE is used as
1731 ;;; the error context for any error message, and CONTEXT is a string
1732 ;;; that is spliced into the warning.
1733 (declaim (ftype (sfunction ((or symbol function) list node function string)
1734 (values list boolean))
1736 (defun careful-call (function args node warn-fun context)
1738 (multiple-value-list
1739 (handler-case (apply function args)
1741 (let ((*compiler-error-context* node))
1742 (funcall warn-fun "Lisp error during ~A:~%~A" context condition)
1743 (return-from careful-call (values nil nil))))))
1746 ;;; Variations of SPECIFIER-TYPE for parsing possibly wrong
1749 ((deffrob (basic careful compiler transform)
1751 (defun ,careful (specifier)
1752 (handler-case (,basic specifier)
1753 (sb!kernel::arg-count-error (condition)
1754 (values nil (list (format nil "~A" condition))))
1755 (simple-error (condition)
1756 (values nil (list* (simple-condition-format-control condition)
1757 (simple-condition-format-arguments condition))))))
1758 (defun ,compiler (specifier)
1759 (multiple-value-bind (type error-args) (,careful specifier)
1761 (apply #'compiler-error error-args))))
1762 (defun ,transform (specifier)
1763 (multiple-value-bind (type error-args) (,careful specifier)
1765 (apply #'give-up-ir1-transform
1767 (deffrob specifier-type careful-specifier-type compiler-specifier-type ir1-transform-specifier-type)
1768 (deffrob values-specifier-type careful-values-specifier-type compiler-values-specifier-type ir1-transform-values-specifier-type))
1771 ;;;; utilities used at run-time for parsing &KEY args in IR1
1773 ;;; This function is used by the result of PARSE-DEFTRANSFORM to find
1774 ;;; the lvar for the value of the &KEY argument KEY in the list of
1775 ;;; lvars ARGS. It returns the lvar if the keyword is present, or NIL
1776 ;;; otherwise. The legality and constantness of the keywords should
1777 ;;; already have been checked.
1778 (declaim (ftype (sfunction (list keyword) (or lvar null))
1780 (defun find-keyword-lvar (args key)
1781 (do ((arg args (cddr arg)))
1783 (when (eq (lvar-value (first arg)) key)
1784 (return (second arg)))))
1786 ;;; This function is used by the result of PARSE-DEFTRANSFORM to
1787 ;;; verify that alternating lvars in ARGS are constant and that there
1788 ;;; is an even number of args.
1789 (declaim (ftype (sfunction (list) boolean) check-key-args-constant))
1790 (defun check-key-args-constant (args)
1791 (do ((arg args (cddr arg)))
1793 (unless (and (rest arg)
1794 (constant-lvar-p (first arg)))
1797 ;;; This function is used by the result of PARSE-DEFTRANSFORM to
1798 ;;; verify that the list of lvars ARGS is a well-formed &KEY arglist
1799 ;;; and that only keywords present in the list KEYS are supplied.
1800 (declaim (ftype (sfunction (list list) boolean) check-transform-keys))
1801 (defun check-transform-keys (args keys)
1802 (and (check-key-args-constant args)
1803 (do ((arg args (cddr arg)))
1805 (unless (member (lvar-value (first arg)) keys)
1810 ;;; Called by the expansion of the EVENT macro.
1811 (declaim (ftype (sfunction (event-info (or node null)) *) %event))
1812 (defun %event (info node)
1813 (incf (event-info-count info))
1814 (when (and (>= (event-info-level info) *event-note-threshold*)
1815 (policy (or node *lexenv*)
1816 (= inhibit-warnings 0)))
1817 (let ((*compiler-error-context* node))
1818 (compiler-notify (event-info-description info))))
1820 (let ((action (event-info-action info)))
1821 (when action (funcall action node))))
1824 (defun make-cast (value type policy)
1825 (declare (type lvar value)
1827 (type policy policy))
1828 (%make-cast :asserted-type type
1829 :type-to-check (maybe-weaken-check type policy)
1831 :derived-type (coerce-to-values type)))
1833 (defun cast-type-check (cast)
1834 (declare (type cast cast))
1835 (when (cast-reoptimize cast)
1836 (ir1-optimize-cast cast t))
1837 (cast-%type-check cast))
1839 (defun note-single-valuified-lvar (lvar)
1840 (declare (type (or lvar null) lvar))
1842 (let ((use (lvar-uses lvar)))
1844 (let ((leaf (ref-leaf use)))
1845 (when (and (lambda-var-p leaf)
1846 (null (rest (leaf-refs leaf))))
1847 (reoptimize-lambda-var leaf))))
1848 ((or (listp use) (combination-p use))
1849 (do-uses (node lvar)
1850 (setf (node-reoptimize node) t)
1851 (setf (block-reoptimize (node-block node)) t)
1852 (reoptimize-component (node-component node) :maybe)))))))