1 ;;;; This file implements local call analysis. A local call is a
2 ;;;; function call between functions being compiled at the same time.
3 ;;;; If we can tell at compile time that such a call is legal, then we
4 ;;;; change the combination to call the correct lambda, mark it as
5 ;;;; local, and add this link to our call graph. Once a call is local,
6 ;;;; it is then eligible for let conversion, which places the body of
7 ;;;; the function inline.
9 ;;;; We cannot always do a local call even when we do have the
10 ;;;; function being called. Calls that cannot be shown to have legal
11 ;;;; arg counts are not converted.
13 ;;;; This software is part of the SBCL system. See the README file for
14 ;;;; more information.
16 ;;;; This software is derived from the CMU CL system, which was
17 ;;;; written at Carnegie Mellon University and released into the
18 ;;;; public domain. The software is in the public domain and is
19 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
20 ;;;; files for more information.
24 ;;; This function propagates information from the variables in the
25 ;;; function FUN to the actual arguments in CALL. This is also called
26 ;;; by the VALUES IR1 optimizer when it sleazily converts MV-BINDs to
29 ;;; We flush all arguments to CALL that correspond to unreferenced
30 ;;; variables in FUN. We leave NILs in the COMBINATION-ARGS so that
31 ;;; the remaining args still match up with their vars.
33 ;;; We also apply the declared variable type assertion to the argument
35 (defun propagate-to-args (call fun
)
36 (declare (type combination call
) (type clambda fun
))
37 (loop with policy
= (lexenv-policy (node-lexenv call
))
38 for args on
(basic-combination-args call
)
39 and var in
(lambda-vars fun
)
40 do
(assert-lvar-type (car args
) (leaf-type var
) policy
)
41 do
(unless (leaf-refs var
)
42 (flush-dest (car args
))
43 (setf (car args
) nil
)))
46 (defun handle-nested-dynamic-extent-lvars (lvar)
47 (let ((uses (lvar-uses lvar
)))
48 ;; Stack analysis wants DX value generators to end their
49 ;; blocks. Uses of mupltiple used LVARs already end their blocks,
50 ;; so we just need to process used-once LVARs.
52 ;; FIXME: Is this true? I cannot trigger any bad behaviour if I nuke this
53 ;; form, and the only assumption regarding block ends I see in in stack
54 ;; analysis is the one made by MAP-BLOCK-NLXES, which assumes that nodes
55 ;; with cleanups in their lexenv end their blocks. If this one is
56 ;; necessary, we should explain why in more detail. --NS 2008-07-19
58 (node-ends-block uses
))
59 ;; If this LVAR's USE is good for DX, it is either a CAST, or it
60 ;; must be a regular combination whose arguments are potentially DX as well.
64 (handle-nested-dynamic-extent-lvars (cast-value use
)))
66 (loop for arg in
(combination-args use
)
67 when
(lvar-good-for-dx-p arg
)
68 append
(handle-nested-dynamic-extent-lvars arg
))))))
72 when
(use-good-for-dx-p use
)
74 (when (use-good-for-dx-p uses
)
77 (defun recognize-dynamic-extent-lvars (call fun
)
78 (declare (type combination call
) (type clambda fun
))
79 (loop for arg in
(basic-combination-args call
)
80 and var in
(lambda-vars fun
)
81 when
(and arg
(lambda-var-dynamic-extent var
)
82 (not (lvar-dynamic-extent arg
)))
83 append
(handle-nested-dynamic-extent-lvars arg
) into dx-lvars
84 finally
(when dx-lvars
85 ;; Stack analysis requires that the CALL ends the block, so
86 ;; that MAP-BLOCK-NLXES sees the cleanup we insert here.
87 (node-ends-block call
)
88 (let* ((entry (with-ir1-environment-from-node call
90 (cleanup (make-cleanup :kind
:dynamic-extent
93 (setf (entry-cleanup entry
) cleanup
)
94 (insert-node-before call entry
)
95 (setf (node-lexenv call
)
96 (make-lexenv :default
(node-lexenv call
)
98 (push entry
(lambda-entries (node-home-lambda entry
)))
99 (dolist (lvar dx-lvars
)
100 (setf (lvar-dynamic-extent lvar
) cleanup
)))))
103 ;;; This function handles merging the tail sets if CALL is potentially
104 ;;; tail-recursive, and is a call to a function with a different
105 ;;; TAIL-SET than CALL's FUN. This must be called whenever we alter
106 ;;; IR1 so as to place a local call in what might be a tail-recursive
107 ;;; context. Note that any call which returns its value to a RETURN is
108 ;;; considered potentially tail-recursive, since any implicit MV-PROG1
109 ;;; might be optimized away.
111 ;;; We destructively modify the set for the calling function to
112 ;;; represent both, and then change all the functions in callee's set
113 ;;; to reference the first. If we do merge, we reoptimize the
114 ;;; RETURN-RESULT lvar to cause IR1-OPTIMIZE-RETURN to recompute the
116 (defun merge-tail-sets (call &optional
(new-fun (combination-lambda call
)))
117 (declare (type basic-combination call
) (type clambda new-fun
))
118 (let ((return (node-dest call
)))
119 (when (return-p return
)
120 (let ((call-set (lambda-tail-set (node-home-lambda call
)))
121 (fun-set (lambda-tail-set new-fun
)))
122 (unless (eq call-set fun-set
)
123 (let ((funs (tail-set-funs fun-set
)))
125 (setf (lambda-tail-set fun
) call-set
))
126 (setf (tail-set-funs call-set
)
127 (nconc (tail-set-funs call-set
) funs
)))
128 (reoptimize-lvar (return-result return
))
131 ;;; Convert a combination into a local call. We PROPAGATE-TO-ARGS, set
132 ;;; the combination kind to :LOCAL, add FUN to the CALLS of the
133 ;;; function that the call is in, call MERGE-TAIL-SETS, then replace
134 ;;; the function in the REF node with the new function.
136 ;;; We change the REF last, since changing the reference can trigger
137 ;;; LET conversion of the new function, but will only do so if the
138 ;;; call is local. Note that the replacement may trigger LET
139 ;;; conversion or other changes in IR1. We must call MERGE-TAIL-SETS
140 ;;; with NEW-FUN before the substitution, since after the substitution
141 ;;; (and LET conversion), the call may no longer be recognizable as
143 (defun convert-call (ref call fun
)
144 (declare (type ref ref
) (type combination call
) (type clambda fun
))
145 (propagate-to-args call fun
)
146 (setf (basic-combination-kind call
) :local
)
147 (unless (call-full-like-p call
)
148 (dolist (arg (basic-combination-args call
))
150 (flush-lvar-externally-checkable-type arg
))))
151 (sset-adjoin fun
(lambda-calls-or-closes (node-home-lambda call
)))
152 (recognize-dynamic-extent-lvars call fun
)
153 (merge-tail-sets call fun
)
154 (change-ref-leaf ref fun
)
157 ;;;; external entry point creation
159 ;;; Return a LAMBDA form that can be used as the definition of the XEP
162 ;;; If FUN is a LAMBDA, then we check the number of arguments
163 ;;; (conditional on policy) and call FUN with all the arguments.
165 ;;; If FUN is an OPTIONAL-DISPATCH, then we dispatch off of the number
166 ;;; of supplied arguments by doing do an = test for each entry-point,
167 ;;; calling the entry with the appropriate prefix of the passed
170 ;;; If there is a &MORE arg, then there are a couple of optimizations
171 ;;; that we make (more for space than anything else):
172 ;;; -- If MIN-ARGS is 0, then we make the more entry a T clause, since
173 ;;; no argument count error is possible.
174 ;;; -- We can omit the = clause for the last entry-point, allowing the
175 ;;; case of 0 more args to fall through to the more entry.
177 ;;; We don't bother to policy conditionalize wrong arg errors in
178 ;;; optional dispatches, since the additional overhead is negligible
179 ;;; compared to the cost of everything else going on.
181 ;;; Note that if policy indicates it, argument type declarations in
182 ;;; FUN will be verified. Since nothing is known about the type of the
183 ;;; XEP arg vars, type checks will be emitted when the XEP's arg vars
184 ;;; are passed to the actual function.
185 (defun make-xep-lambda-expression (fun)
186 (declare (type functional fun
))
189 (let ((nargs (length (lambda-vars fun
)))
190 (n-supplied (gensym))
191 (temps (make-gensym-list (length (lambda-vars fun
)))))
192 `(lambda (,n-supplied
,@temps
)
193 (declare (type index
,n-supplied
))
194 ,(if (policy *lexenv
* (zerop verify-arg-count
))
195 `(declare (ignore ,n-supplied
))
196 `(%verify-arg-count
,n-supplied
,nargs
))
198 (declare (optimize (merge-tail-calls 3)))
199 (%funcall
,fun
,@temps
)))))
201 (let* ((min (optional-dispatch-min-args fun
))
202 (max (optional-dispatch-max-args fun
))
203 (more (optional-dispatch-more-entry fun
))
204 (n-supplied (gensym))
205 (temps (make-gensym-list max
)))
207 ;; Force convertion of all entries
208 (optional-dispatch-entry-point-fun fun
0)
209 (loop for ep in
(optional-dispatch-entry-points fun
)
211 do
(entries `((eql ,n-supplied
,n
)
212 (%funcall
,(force ep
) ,@(subseq temps
0 n
)))))
213 `(lambda (,n-supplied
,@temps
)
214 ;; FIXME: Make sure that INDEX type distinguishes between
215 ;; target and host. (Probably just make the SB!XC:DEFTYPE
216 ;; different from CL:DEFTYPE.)
217 (declare (type index
,n-supplied
))
219 ,@(if more
(butlast (entries)) (entries))
221 ;; KLUDGE: (NOT (< ...)) instead of >= avoids one round of
222 ;; deftransforms and lambda-conversion.
223 `((,(if (zerop min
) t
`(not (< ,n-supplied
,max
)))
224 ,(let ((n-context (gensym))
226 `(multiple-value-bind (,n-context
,n-count
)
227 (%more-arg-context
,n-supplied
,max
)
229 (declare (optimize (merge-tail-calls 3)))
230 (%funcall
,more
,@temps
,n-context
,n-count
)))))))
232 (%arg-count-error
,n-supplied
)))))))))
234 ;;; Make an external entry point (XEP) for FUN and return it. We
235 ;;; convert the result of MAKE-XEP-LAMBDA in the correct environment,
236 ;;; then associate this lambda with FUN as its XEP. After the
237 ;;; conversion, we iterate over the function's associated lambdas,
238 ;;; redoing local call analysis so that the XEP calls will get
241 ;;; We set REANALYZE and REOPTIMIZE in the component, just in case we
242 ;;; discover an XEP after the initial local call analyze pass.
243 (defun make-xep (fun)
244 (declare (type functional fun
))
245 (aver (null (functional-entry-fun fun
)))
246 (with-ir1-environment-from-node (lambda-bind (main-entry fun
))
247 (let ((res (ir1-convert-lambda (make-xep-lambda-expression fun
)
248 :debug-name
(debug-name
249 'xep
(leaf-debug-name fun
)))))
250 (setf (functional-kind res
) :external
251 (leaf-ever-used res
) t
252 (functional-entry-fun res
) fun
253 (functional-entry-fun fun
) res
254 (component-reanalyze *current-component
*) t
)
255 (reoptimize-component *current-component
* :maybe
)
258 (locall-analyze-fun-1 fun
))
260 (dolist (ep (optional-dispatch-entry-points fun
))
261 (locall-analyze-fun-1 (force ep
)))
262 (when (optional-dispatch-more-entry fun
)
263 (locall-analyze-fun-1 (optional-dispatch-more-entry fun
)))))
266 ;;; Notice a REF that is not in a local-call context. If the REF is
267 ;;; already to an XEP, then do nothing, otherwise change it to the
268 ;;; XEP, making an XEP if necessary.
270 ;;; If REF is to a special :CLEANUP or :ESCAPE function, then we treat
271 ;;; it as though it was not an XEP reference (i.e. leave it alone).
272 (defun reference-entry-point (ref)
273 (declare (type ref ref
))
274 (let ((fun (ref-leaf ref
)))
275 (unless (or (xep-p fun
)
276 (member (functional-kind fun
) '(:escape
:cleanup
)))
277 (change-ref-leaf ref
(or (functional-entry-fun fun
)
280 ;;; Attempt to convert all references to FUN to local calls. The
281 ;;; reference must be the function for a call, and the function lvar
282 ;;; must be used only once, since otherwise we cannot be sure what
283 ;;; function is to be called. The call lvar would be multiply used if
284 ;;; there is hairy stuff such as conditionals in the expression that
285 ;;; computes the function.
287 ;;; If we cannot convert a reference, then we mark the referenced
288 ;;; function as an entry-point, creating a new XEP if necessary. We
289 ;;; don't try to convert calls that are in error (:ERROR kind.)
291 ;;; This is broken off from LOCALL-ANALYZE-COMPONENT so that people
292 ;;; can force analysis of newly introduced calls. Note that we don't
293 ;;; do LET conversion here.
294 (defun locall-analyze-fun-1 (fun)
295 (declare (type functional fun
))
296 (let ((refs (leaf-refs fun
))
299 (let* ((lvar (node-lvar ref
))
300 (dest (when lvar
(lvar-dest lvar
))))
301 (unless (node-to-be-deleted-p ref
)
302 (cond ((and (basic-combination-p dest
)
303 (eq (basic-combination-fun dest
) lvar
)
304 (eq (lvar-uses lvar
) ref
))
306 (convert-call-if-possible ref dest
)
308 (unless (eq (basic-combination-kind dest
) :local
)
309 (reference-entry-point ref
)
312 (reference-entry-point ref
)
313 (setq local-p nil
))))))
314 (when local-p
(note-local-functional fun
)))
318 ;;; We examine all NEW-FUNCTIONALS in COMPONENT, attempting to convert
319 ;;; calls into local calls when it is legal. We also attempt to
320 ;;; convert each LAMBDA to a LET. LET conversion is also triggered by
321 ;;; deletion of a function reference, but functions that start out
322 ;;; eligible for conversion must be noticed sometime.
324 ;;; Note that there is a lot of action going on behind the scenes
325 ;;; here, triggered by reference deletion. In particular, the
326 ;;; COMPONENT-LAMBDAS are being hacked to remove newly deleted and LET
327 ;;; converted LAMBDAs, so it is important that the LAMBDA is added to
328 ;;; the COMPONENT-LAMBDAS when it is. Also, the
329 ;;; COMPONENT-NEW-FUNCTIONALS may contain all sorts of drivel, since
330 ;;; it is not updated when we delete functions, etc. Only
331 ;;; COMPONENT-LAMBDAS is updated.
333 ;;; COMPONENT-REANALYZE-FUNCTIONALS is treated similarly to
334 ;;; COMPONENT-NEW-FUNCTIONALS, but we don't add lambdas to the
336 (defun locall-analyze-component (component)
337 (declare (type component component
))
338 (aver-live-component component
)
340 (let* ((new-functional (pop (component-new-functionals component
)))
341 (functional (or new-functional
342 (pop (component-reanalyze-functionals component
)))))
345 (let ((kind (functional-kind functional
)))
346 (cond ((or (functional-somewhat-letlike-p functional
)
347 (memq kind
'(:deleted
:zombie
)))
348 (values)) ; nothing to do
349 ((and (null (leaf-refs functional
)) (eq kind nil
)
350 (not (functional-entry-fun functional
)))
351 (delete-functional functional
))
353 ;; Fix/check FUNCTIONAL's relationship to COMPONENT-LAMDBAS.
354 (cond ((not (lambda-p functional
))
355 ;; Since FUNCTIONAL isn't a LAMBDA, this doesn't
358 (new-functional ; FUNCTIONAL came from
359 ; NEW-FUNCTIONALS, hence is new.
360 ;; FUNCTIONAL becomes part of COMPONENT-LAMBDAS now.
361 (aver (not (member functional
362 (component-lambdas component
))))
363 (push functional
(component-lambdas component
)))
364 (t ; FUNCTIONAL is old.
365 ;; FUNCTIONAL should be in COMPONENT-LAMBDAS already.
366 (aver (member functional
(component-lambdas
368 (locall-analyze-fun-1 functional
)
369 (when (lambda-p functional
)
370 (maybe-let-convert functional
)))))))
373 (defun locall-analyze-clambdas-until-done (clambdas)
375 (let ((did-something nil
))
376 (dolist (clambda clambdas
)
377 (let ((component (lambda-component clambda
)))
378 ;; The original CMU CL code seemed to implicitly assume that
379 ;; COMPONENT is the only one here. Let's make that explicit.
380 (aver (= 1 (length (functional-components clambda
))))
381 (aver (eql component
(first (functional-components clambda
))))
382 (when (or (component-new-functionals component
)
383 (component-reanalyze-functionals component
))
384 (setf did-something t
)
385 (locall-analyze-component component
))))
386 (unless did-something
390 ;;; If policy is auspicious and CALL is not in an XEP and we don't seem
391 ;;; to be in an infinite recursive loop, then change the reference to
392 ;;; reference a fresh copy. We return whichever function we decide to
394 (defun maybe-expand-local-inline (original-functional ref call
)
395 (if (and (policy call
396 (and (>= speed space
)
397 (>= speed compilation-speed
)))
398 (not (eq (functional-kind (node-home-lambda call
)) :external
))
399 (inline-expansion-ok call
))
400 (let* ((end (component-last-block (node-component call
)))
401 (pred (block-prev end
)))
402 (multiple-value-bind (losing-local-object converted-lambda
)
403 (catch 'locall-already-let-converted
404 (with-ir1-environment-from-node call
405 (let ((*lexenv
* (functional-lexenv original-functional
)))
408 (functional-inline-expansion original-functional
)
409 :debug-name
(debug-name 'local-inline
411 original-functional
)))))))
412 (cond (losing-local-object
413 (if (functional-p losing-local-object
)
414 (let ((*compiler-error-context
* call
))
415 (compiler-notify "couldn't inline expand because expansion ~
416 calls this LET-converted local function:~
418 (leaf-debug-name losing-local-object
)))
419 (let ((*compiler-error-context
* call
))
420 (compiler-notify "implementation limitation: couldn't inline ~
421 expand because expansion refers to ~
422 the optimized away object ~S."
423 losing-local-object
)))
424 (loop for block
= (block-next pred
) then
(block-next block
)
426 do
(setf (block-delete-p block
) t
))
427 (loop for block
= (block-next pred
) then
(block-next block
)
429 do
(delete-block block t
))
432 (change-ref-leaf ref converted-lambda
)
434 original-functional
))
436 ;;; Dispatch to the appropriate function to attempt to convert a call.
437 ;;; REF must be a reference to a FUNCTIONAL. This is called in IR1
438 ;;; optimization as well as in local call analysis. If the call is is
439 ;;; already :LOCAL, we do nothing. If the call is already scheduled
440 ;;; for deletion, also do nothing (in addition to saving time, this
441 ;;; also avoids some problems with optimizing collections of functions
442 ;;; that are partially deleted.)
444 ;;; This is called both before and after FIND-INITIAL-DFO runs. When
445 ;;; called on a :INITIAL component, we don't care whether the caller
446 ;;; and callee are in the same component. Afterward, we must stick
447 ;;; with whatever component division we have chosen.
449 ;;; Before attempting to convert a call, we see whether the function
450 ;;; is supposed to be inline expanded. Call conversion proceeds as
451 ;;; before after any expansion.
453 ;;; We bind *COMPILER-ERROR-CONTEXT* to the node for the call so that
454 ;;; warnings will get the right context.
455 (defun convert-call-if-possible (ref call
)
456 (declare (type ref ref
) (type basic-combination call
))
457 (let* ((block (node-block call
))
458 (component (block-component block
))
459 (original-fun (ref-leaf ref
)))
460 (aver (functional-p original-fun
))
461 (unless (or (member (basic-combination-kind call
) '(:local
:error
))
462 (node-to-be-deleted-p call
)
463 (member (functional-kind original-fun
)
464 '(:toplevel-xep
:deleted
))
465 (not (or (eq (component-kind component
) :initial
)
468 (lambda-bind (main-entry original-fun
))))
470 (let ((fun (if (xep-p original-fun
)
471 (functional-entry-fun original-fun
)
473 (*compiler-error-context
* call
))
475 (when (and (eq (functional-inlinep fun
) :inline
)
476 (rest (leaf-refs original-fun
)))
477 (setq fun
(maybe-expand-local-inline fun ref call
)))
479 (aver (member (functional-kind fun
)
480 '(nil :escape
:cleanup
:optional
)))
481 (cond ((mv-combination-p call
)
482 (convert-mv-call ref call fun
))
484 (convert-lambda-call ref call fun
))
486 (convert-hairy-call ref call fun
))))))
490 ;;; Attempt to convert a multiple-value call. The only interesting
491 ;;; case is a call to a function that LOOKS-LIKE-AN-MV-BIND, has
492 ;;; exactly one reference and no XEP, and is called with one values
495 ;;; We change the call to be to the last optional entry point and
496 ;;; change the call to be local. Due to our preconditions, the call
497 ;;; should eventually be converted to a let, but we can't do that now,
498 ;;; since there may be stray references to the e-p lambda due to
499 ;;; optional defaulting code.
501 ;;; We also use variable types for the called function to construct an
502 ;;; assertion for the values lvar.
504 ;;; See CONVERT-CALL for additional notes on MERGE-TAIL-SETS, etc.
505 (defun convert-mv-call (ref call fun
)
506 (declare (type ref ref
) (type mv-combination call
) (type functional fun
))
507 (when (and (looks-like-an-mv-bind fun
)
508 (singleton-p (leaf-refs fun
))
509 (singleton-p (basic-combination-args call
)))
510 (let* ((*current-component
* (node-component ref
))
511 (ep (optional-dispatch-entry-point-fun
512 fun
(optional-dispatch-max-args fun
))))
513 (when (null (leaf-refs ep
))
514 (aver (= (optional-dispatch-min-args fun
) 0))
515 (aver (not (functional-entry-fun fun
)))
516 (setf (basic-combination-kind call
) :local
)
517 (sset-adjoin ep
(lambda-calls-or-closes (node-home-lambda call
)))
518 (merge-tail-sets call ep
)
519 (change-ref-leaf ref ep
)
522 (first (basic-combination-args call
))
523 (make-short-values-type (mapcar #'leaf-type
(lambda-vars ep
)))
524 (lexenv-policy (node-lexenv call
))))))
527 ;;; Attempt to convert a call to a lambda. If the number of args is
528 ;;; wrong, we give a warning and mark the call as :ERROR to remove it
529 ;;; from future consideration. If the argcount is O.K. then we just
531 (defun convert-lambda-call (ref call fun
)
532 (declare (type ref ref
) (type combination call
) (type clambda fun
))
533 (let ((nargs (length (lambda-vars fun
)))
534 (n-call-args (length (combination-args call
))))
535 (cond ((= n-call-args nargs
)
536 (convert-call ref call fun
))
539 'local-argument-mismatch
541 "function called with ~R argument~:P, but wants exactly ~R"
542 :format-arguments
(list n-call-args nargs
))
543 (setf (basic-combination-kind call
) :error
)))))
545 ;;;; &OPTIONAL, &MORE and &KEYWORD calls
547 ;;; This is similar to CONVERT-LAMBDA-CALL, but deals with
548 ;;; OPTIONAL-DISPATCHes. If only fixed args are supplied, then convert
549 ;;; a call to the correct entry point. If &KEY args are supplied, then
550 ;;; dispatch to a subfunction. We don't convert calls to functions
551 ;;; that have a &MORE (or &REST) arg.
552 (defun convert-hairy-call (ref call fun
)
553 (declare (type ref ref
) (type combination call
)
554 (type optional-dispatch fun
))
555 (let ((min-args (optional-dispatch-min-args fun
))
556 (max-args (optional-dispatch-max-args fun
))
557 (call-args (length (combination-args call
))))
558 (cond ((< call-args min-args
)
560 'local-argument-mismatch
562 "function called with ~R argument~:P, but wants at least ~R"
563 :format-arguments
(list call-args min-args
))
564 (setf (basic-combination-kind call
) :error
))
565 ((<= call-args max-args
)
566 (convert-call ref call
567 (let ((*current-component
* (node-component ref
)))
568 (optional-dispatch-entry-point-fun
569 fun
(- call-args min-args
)))))
570 ((optional-dispatch-more-entry fun
)
571 (convert-more-call ref call fun
))
574 'local-argument-mismatch
576 "function called with ~R argument~:P, but wants at most ~R"
578 (list call-args max-args
))
579 (setf (basic-combination-kind call
) :error
))))
582 ;;; This function is used to convert a call to an entry point when
583 ;;; complex transformations need to be done on the original arguments.
584 ;;; ENTRY is the entry point function that we are calling. VARS is a
585 ;;; list of variable names which are bound to the original call
586 ;;; arguments. IGNORES is the subset of VARS which are ignored. ARGS
587 ;;; is the list of arguments to the entry point function.
589 ;;; In order to avoid gruesome graph grovelling, we introduce a new
590 ;;; function that rearranges the arguments and calls the entry point.
591 ;;; We analyze the new function and the entry point immediately so
592 ;;; that everything gets converted during the single pass.
593 (defun convert-hairy-fun-entry (ref call entry vars ignores args
)
594 (declare (list vars ignores args
) (type ref ref
) (type combination call
)
595 (type clambda entry
))
597 (with-ir1-environment-from-node call
600 (declare (ignorable ,@ignores
))
601 (%funcall
,entry
,@args
))
602 :debug-name
(debug-name 'hairy-function-entry
604 (basic-combination-fun call
)))))))
605 (convert-call ref call new-fun
)
606 (dolist (ref (leaf-refs entry
))
607 (convert-call-if-possible ref
(lvar-dest (node-lvar ref
))))))
609 ;;; Use CONVERT-HAIRY-FUN-ENTRY to convert a &MORE-arg call to a known
610 ;;; function into a local call to the MAIN-ENTRY.
612 ;;; First we verify that all keywords are constant and legal. If there
613 ;;; aren't, then we warn the user and don't attempt to convert the call.
615 ;;; We massage the supplied &KEY arguments into the order expected
616 ;;; by the main entry. This is done by binding all the arguments to
617 ;;; the keyword call to variables in the introduced lambda, then
618 ;;; passing these values variables in the correct order when calling
619 ;;; the main entry. Unused arguments (such as the keywords themselves)
620 ;;; are discarded simply by not passing them along.
622 ;;; If there is a &REST arg, then we bundle up the args and pass them
624 (defun convert-more-call (ref call fun
)
625 (declare (type ref ref
) (type combination call
) (type optional-dispatch fun
))
626 (let* ((max (optional-dispatch-max-args fun
))
627 (arglist (optional-dispatch-arglist fun
))
628 (args (combination-args call
))
629 (more (nthcdr max args
))
630 (flame (policy call
(or (> speed inhibit-warnings
)
631 (> space inhibit-warnings
))))
635 (temps (make-gensym-list max
))
636 (more-temps (make-gensym-list (length more
))))
641 (dolist (var arglist
)
642 (let ((info (lambda-var-arg-info var
)))
644 (ecase (arg-info-kind info
)
648 ((:more-context
:more-count
)
649 (compiler-warn "can't local-call functions with &MORE args")
650 (setf (basic-combination-kind call
) :error
)
651 (return-from convert-more-call
))))))
653 (when (optional-dispatch-keyp fun
)
654 (when (oddp (length more
))
655 (compiler-warn "function called with odd number of ~
656 arguments in keyword portion")
657 (setf (basic-combination-kind call
) :error
)
658 (return-from convert-more-call
))
660 (do ((key more
(cddr key
))
661 (temp more-temps
(cddr temp
)))
663 (let ((lvar (first key
)))
664 (unless (constant-lvar-p lvar
)
666 (compiler-notify "non-constant keyword in keyword call"))
667 (setf (basic-combination-kind call
) :error
)
668 (return-from convert-more-call
))
670 (let ((name (lvar-value lvar
))
673 (when (and (eq name
:allow-other-keys
) (not allow-found
))
674 (let ((val (second key
)))
675 (cond ((constant-lvar-p val
)
677 allowp
(lvar-value val
)))
679 (compiler-notify "non-constant :ALLOW-OTHER-KEYS value"))
680 (setf (basic-combination-kind call
) :error
)
681 (return-from convert-more-call
)))))
682 (dolist (var (key-vars)
685 (unless (eq name
:allow-other-keys
)
686 (setq loser
(list name
)))))
687 (let ((info (lambda-var-arg-info var
)))
688 (when (eq (arg-info-key info
) name
)
690 (if (member var
(supplied) :key
#'car
)
692 (supplied (cons var val
)))
695 (when (and loser
(not (optional-dispatch-allowp fun
)) (not allowp
))
696 (compiler-warn "function called with unknown argument keyword ~S"
698 (setf (basic-combination-kind call
) :error
)
699 (return-from convert-more-call
)))
701 (collect ((call-args))
702 (do ((var arglist
(cdr var
))
703 (temp temps
(cdr temp
)))
705 (let ((info (lambda-var-arg-info (car var
))))
707 (ecase (arg-info-kind info
)
709 (call-args (car temp
))
710 (when (arg-info-supplied-p info
)
713 (call-args `(list ,@more-temps
))
717 (call-args (car temp
)))))
719 (dolist (var (key-vars))
720 (let ((info (lambda-var-arg-info var
))
721 (temp (cdr (assoc var
(supplied)))))
724 (call-args (arg-info-default info
)))
725 (when (arg-info-supplied-p info
)
726 (call-args (not (null temp
))))))
728 (convert-hairy-fun-entry ref call
(optional-dispatch-main-entry fun
)
729 (append temps more-temps
)
730 (ignores) (call-args)))))
736 ;;;; Converting to a LET has differing significance to various parts
737 ;;;; of the compiler:
738 ;;;; -- The body of a LET is spliced in immediately after the
739 ;;;; corresponding combination node, making the control transfer
740 ;;;; explicit and allowing LETs to be mashed together into a single
741 ;;;; block. The value of the LET is delivered directly to the
742 ;;;; original lvar for the call, eliminating the need to
743 ;;;; propagate information from the dummy result lvar.
744 ;;;; -- As far as IR1 optimization is concerned, it is interesting in
745 ;;;; that there is only one expression that the variable can be bound
746 ;;;; to, and this is easily substituted for.
747 ;;;; -- LETs are interesting to environment analysis and to the back
748 ;;;; end because in most ways a LET can be considered to be "the
749 ;;;; same function" as its home function.
750 ;;;; -- LET conversion has dynamic scope implications, since control
751 ;;;; transfers within the same environment are local. In a local
752 ;;;; control transfer, cleanup code must be emitted to remove
753 ;;;; dynamic bindings that are no longer in effect.
755 ;;; Set up the control transfer to the called CLAMBDA. We split the
756 ;;; call block immediately after the call, and link the head of
757 ;;; CLAMBDA to the call block. The successor block after splitting
758 ;;; (where we return to) is returned.
760 ;;; If the lambda is is a different component than the call, then we
761 ;;; call JOIN-COMPONENTS. This only happens in block compilation
762 ;;; before FIND-INITIAL-DFO.
763 (defun insert-let-body (clambda call
)
764 (declare (type clambda clambda
) (type basic-combination call
))
765 (let* ((call-block (node-block call
))
766 (bind-block (node-block (lambda-bind clambda
)))
767 (component (block-component call-block
)))
768 (aver-live-component component
)
769 (let ((clambda-component (block-component bind-block
)))
770 (unless (eq clambda-component component
)
771 (aver (eq (component-kind component
) :initial
))
772 (join-components component clambda-component
)))
773 (let ((*current-component
* component
))
774 (node-ends-block call
))
775 (destructuring-bind (next-block)
776 (block-succ call-block
)
777 (unlink-blocks call-block next-block
)
778 (link-blocks call-block bind-block
)
781 ;;; Remove CLAMBDA from the tail set of anything it used to be in the
782 ;;; same set as; but leave CLAMBDA with a valid tail set value of
783 ;;; its own, for the benefit of code which might try to pull
784 ;;; something out of it (e.g. return type).
785 (defun depart-from-tail-set (clambda)
786 ;; Until sbcl-0.pre7.37.flaky5.2, we did
787 ;; (LET ((TAILS (LAMBDA-TAIL-SET CLAMBDA)))
788 ;; (SETF (TAIL-SET-FUNS TAILS)
789 ;; (DELETE CLAMBDA (TAIL-SET-FUNS TAILS))))
790 ;; (SETF (LAMBDA-TAIL-SET CLAMBDA) NIL)
791 ;; here. Apparently the idea behind the (SETF .. NIL) was that since
792 ;; TAIL-SET-FUNS no longer thinks we're in the tail set, it's
793 ;; inconsistent, and perhaps unsafe, for us to think we're in the
794 ;; tail set. Unfortunately..
796 ;; The (SETF .. NIL) caused problems in sbcl-0.pre7.37.flaky5.2 when
797 ;; I was trying to get Python to emit :EXTERNAL LAMBDAs directly
798 ;; (instead of only being able to emit funny little :TOPLEVEL stubs
799 ;; which you called in order to get the address of an external LAMBDA):
800 ;; the external function was defined in terms of internal function,
801 ;; which was LET-converted, and then things blew up downstream when
802 ;; FINALIZE-XEP-DEFINITION tried to find out its DEFINED-TYPE from
803 ;; the now-NILed-out TAIL-SET. So..
805 ;; To deal with this problem, we no longer NIL out
806 ;; (LAMBDA-TAIL-SET CLAMBDA) here. Instead:
807 ;; * If we're the only function in TAIL-SET-FUNS, it should
808 ;; be safe to leave ourself linked to it, and it to you.
809 ;; * If there are other functions in TAIL-SET-FUNS, then we're
810 ;; afraid of future optimizations on those functions causing
811 ;; the TAIL-SET object no longer to be valid to describe our
812 ;; return value. Thus, we delete ourselves from that object;
813 ;; but we save a newly-allocated tail-set, derived from the old
814 ;; one, for ourselves, for the use of later code (e.g.
815 ;; FINALIZE-XEP-DEFINITION) which might want to
816 ;; know about our return type.
817 (let* ((old-tail-set (lambda-tail-set clambda
))
818 (old-tail-set-funs (tail-set-funs old-tail-set
)))
819 (unless (= 1 (length old-tail-set-funs
))
820 (setf (tail-set-funs old-tail-set
)
821 (delete clambda old-tail-set-funs
))
822 (let ((new-tail-set (copy-tail-set old-tail-set
)))
823 (setf (lambda-tail-set clambda
) new-tail-set
824 (tail-set-funs new-tail-set
) (list clambda
)))))
825 ;; The documentation on TAIL-SET-INFO doesn't tell whether it could
826 ;; remain valid in this case, so we nuke it on the theory that
827 ;; missing information tends to be less dangerous than incorrect
829 (setf (tail-set-info (lambda-tail-set clambda
)) nil
))
831 ;;; Handle the PHYSENV semantics of LET conversion. We add CLAMBDA and
832 ;;; its LETs to LETs for the CALL's home function. We merge the calls
833 ;;; for CLAMBDA with the calls for the home function, removing CLAMBDA
834 ;;; in the process. We also merge the ENTRIES.
836 ;;; We also unlink the function head from the component head and set
837 ;;; COMPONENT-REANALYZE to true to indicate that the DFO should be
839 (defun merge-lets (clambda call
)
841 (declare (type clambda clambda
) (type basic-combination call
))
843 (let ((component (node-component call
)))
844 (unlink-blocks (component-head component
) (lambda-block clambda
))
845 (setf (component-lambdas component
)
846 (delete clambda
(component-lambdas component
)))
847 (setf (component-reanalyze component
) t
))
848 (setf (lambda-call-lexenv clambda
) (node-lexenv call
))
850 (depart-from-tail-set clambda
)
852 (let* ((home (node-home-lambda call
))
853 (home-physenv (lambda-physenv home
))
854 (physenv (lambda-physenv clambda
)))
856 (aver (not (eq home clambda
)))
858 ;; CLAMBDA belongs to HOME now.
859 (push clambda
(lambda-lets home
))
860 (setf (lambda-home clambda
) home
)
861 (setf (lambda-physenv clambda
) home-physenv
)
864 (setf (physenv-nlx-info home-physenv
)
865 (nconc (physenv-nlx-info physenv
)
866 (physenv-nlx-info home-physenv
))))
868 ;; All of CLAMBDA's LETs belong to HOME now.
869 (let ((lets (lambda-lets clambda
)))
871 (setf (lambda-home let
) home
)
872 (setf (lambda-physenv let
) home-physenv
))
873 (setf (lambda-lets home
) (nconc lets
(lambda-lets home
))))
874 ;; CLAMBDA no longer has an independent existence as an entity
876 (setf (lambda-lets clambda
) nil
)
878 ;; HOME no longer calls CLAMBDA, and owns all of CLAMBDA's old
880 (sset-union (lambda-calls-or-closes home
)
881 (lambda-calls-or-closes clambda
))
882 (sset-delete clambda
(lambda-calls-or-closes home
))
883 ;; CLAMBDA no longer has an independent existence as an entity
884 ;; which calls things or has DFO dependencies.
885 (setf (lambda-calls-or-closes clambda
) nil
)
887 ;; All of CLAMBDA's ENTRIES belong to HOME now.
888 (setf (lambda-entries home
)
889 (nconc (lambda-entries clambda
)
890 (lambda-entries home
)))
891 ;; CLAMBDA no longer has an independent existence as an entity
893 (setf (lambda-entries clambda
) nil
))
897 ;;; Handle the value semantics of LET conversion. Delete FUN's return
898 ;;; node, and change the control flow to transfer to NEXT-BLOCK
899 ;;; instead. Move all the uses of the result lvar to CALL's lvar.
900 (defun move-return-uses (fun call next-block
)
901 (declare (type clambda fun
) (type basic-combination call
)
902 (type cblock next-block
))
903 (let* ((return (lambda-return fun
))
905 (ensure-block-start (node-prev return
))
906 (node-block return
))))
907 (unlink-blocks return-block
908 (component-tail (block-component return-block
)))
909 (link-blocks return-block next-block
)
911 (delete-return return
)
912 (let ((result (return-result return
))
913 (lvar (if (node-tail-p call
)
914 (return-result (lambda-return (node-home-lambda call
)))
916 (call-type (node-derived-type call
)))
917 (unless (eq call-type
*wild-type
*)
918 ;; FIXME: Replace the call with unsafe CAST. -- APD, 2003-01-26
919 (do-uses (use result
)
920 (derive-node-type use call-type
)))
921 (substitute-lvar-uses lvar result
922 (and lvar
(eq (lvar-uses lvar
) call
)))))
925 ;;; We are converting FUN to be a LET when the call is in a non-tail
926 ;;; position. Any previously tail calls in FUN are no longer tail
927 ;;; calls, and must be restored to normal calls which transfer to
928 ;;; NEXT-BLOCK (FUN's return point.) We can't do this by DO-USES on
929 ;;; the RETURN-RESULT, because the return might have been deleted (if
930 ;;; all calls were TR.)
931 (defun unconvert-tail-calls (fun call next-block
)
932 (do-sset-elements (called (lambda-calls-or-closes fun
))
933 (when (lambda-p called
)
934 (dolist (ref (leaf-refs called
))
935 (let ((this-call (node-dest ref
)))
937 (node-tail-p this-call
)
938 (eq (node-home-lambda this-call
) fun
))
939 (setf (node-tail-p this-call
) nil
)
940 (ecase (functional-kind called
)
941 ((nil :cleanup
:optional
)
942 (let ((block (node-block this-call
))
943 (lvar (node-lvar call
)))
944 (unlink-blocks block
(first (block-succ block
)))
945 (link-blocks block next-block
)
946 (aver (not (node-lvar this-call
)))
947 (add-lvar-use this-call lvar
)))
949 ;; The called function might be an assignment in the
950 ;; case where we are currently converting that function.
951 ;; In steady-state, assignments never appear as a called
954 (aver (eq called fun
)))))))))
957 ;;; Deal with returning from a LET or assignment that we are
958 ;;; converting. FUN is the function we are calling, CALL is a call to
959 ;;; FUN, and NEXT-BLOCK is the return point for a non-tail call, or
960 ;;; NULL if call is a tail call.
962 ;;; If the call is not a tail call, then we must do
963 ;;; UNCONVERT-TAIL-CALLS, since a tail call is a call which returns
964 ;;; its value out of the enclosing non-let function. When call is
965 ;;; non-TR, we must convert it back to an ordinary local call, since
966 ;;; the value must be delivered to the receiver of CALL's value.
968 ;;; We do different things depending on whether the caller and callee
969 ;;; have returns left:
971 ;;; -- If the callee has no return we just do MOVE-LET-CALL-CONT.
972 ;;; Either the function doesn't return, or all returns are via
973 ;;; tail-recursive local calls.
974 ;;; -- If CALL is a non-tail call, or if both have returns, then
975 ;;; we delete the callee's return, move its uses to the call's
976 ;;; result lvar, and transfer control to the appropriate
978 ;;; -- If the callee has a return, but the caller doesn't, then we
979 ;;; move the return to the caller.
980 (defun move-return-stuff (fun call next-block
)
981 (declare (type clambda fun
) (type basic-combination call
)
982 (type (or cblock null
) next-block
))
984 (unconvert-tail-calls fun call next-block
))
985 (let* ((return (lambda-return fun
))
986 (call-fun (node-home-lambda call
))
987 (call-return (lambda-return call-fun
)))
988 (when (and call-return
989 (block-delete-p (node-block call-return
)))
990 (delete-return call-return
)
991 (unlink-node call-return
)
992 (setq call-return nil
))
994 ((or next-block call-return
)
995 (unless (block-delete-p (node-block return
))
997 (ensure-block-start (node-prev call-return
))
998 (setq next-block
(node-block call-return
)))
999 (move-return-uses fun call next-block
)))
1001 (aver (node-tail-p call
))
1002 (setf (lambda-return call-fun
) return
)
1003 (setf (return-lambda return
) call-fun
)
1004 (setf (lambda-return fun
) nil
))))
1005 (%delete-lvar-use call
) ; LET call does not have value semantics
1008 ;;; Actually do LET conversion. We call subfunctions to do most of the
1009 ;;; work. We do REOPTIMIZE-LVAR on the args and CALL's lvar so that
1010 ;;; LET-specific IR1 optimizations get a chance. We blow away any
1011 ;;; entry for the function in *FREE-FUNS* so that nobody will create
1012 ;;; new references to it.
1013 (defun let-convert (fun call
)
1014 (declare (type clambda fun
) (type basic-combination call
))
1015 (let* ((next-block (insert-let-body fun call
))
1016 (next-block (if (node-tail-p call
)
1019 (move-return-stuff fun call next-block
)
1020 (merge-lets fun call
)
1021 (setf (node-tail-p call
) nil
)
1022 ;; If CALL has a derive type NIL, it means that "its return" is
1023 ;; unreachable, but the next BIND is still reachable; in order to
1024 ;; not confuse MAYBE-TERMINATE-BLOCK...
1025 (setf (node-derived-type call
) *wild-type
*)))
1027 ;;; Reoptimize all of CALL's args and its result.
1028 (defun reoptimize-call (call)
1029 (declare (type basic-combination call
))
1030 (dolist (arg (basic-combination-args call
))
1032 (reoptimize-lvar arg
)))
1033 (reoptimize-lvar (node-lvar call
))
1036 ;;; Are there any declarations in force to say CLAMBDA shouldn't be
1038 (defun declarations-suppress-let-conversion-p (clambda)
1039 ;; From the user's point of view, LET-converting something that
1040 ;; has a name is inlining it. (The user can't see what we're doing
1041 ;; with anonymous things, and suppressing inlining
1042 ;; for such things can easily give Python acute indigestion, so
1044 (when (leaf-has-source-name-p clambda
)
1045 ;; ANSI requires that explicit NOTINLINE be respected.
1046 (or (eq (lambda-inlinep clambda
) :notinline
)
1047 ;; If (= LET-CONVERSION 0) we can guess that inlining
1048 ;; generally won't be appreciated, but if the user
1049 ;; specifically requests inlining, that takes precedence over
1050 ;; our general guess.
1051 (and (policy clambda
(= let-conversion
0))
1052 (not (eq (lambda-inlinep clambda
) :inline
))))))
1054 ;;; We also don't convert calls to named functions which appear in the
1055 ;;; initial component, delaying this until optimization. This
1056 ;;; minimizes the likelihood that we will LET-convert a function which
1057 ;;; may have references added due to later local inline expansion.
1058 (defun ok-initial-convert-p (fun)
1059 (not (and (leaf-has-source-name-p fun
)
1060 (or (declarations-suppress-let-conversion-p fun
)
1061 (eq (component-kind (lambda-component fun
))
1064 ;;; This function is called when there is some reason to believe that
1065 ;;; CLAMBDA might be converted into a LET. This is done after local
1066 ;;; call analysis, and also when a reference is deleted. We return
1067 ;;; true if we converted.
1068 (defun maybe-let-convert (clambda)
1069 (declare (type clambda clambda
))
1070 (unless (or (declarations-suppress-let-conversion-p clambda
)
1071 (functional-has-external-references-p clambda
))
1072 ;; We only convert to a LET when the function is a normal local
1073 ;; function, has no XEP, and is referenced in exactly one local
1074 ;; call. Conversion is also inhibited if the only reference is in
1075 ;; a block about to be deleted.
1077 ;; These rules limiting LET conversion may seem unnecessarily
1078 ;; restrictive, since there are some cases where we could do the
1079 ;; return with a jump that don't satisfy these requirements. The
1080 ;; reason for doing things this way is that it makes the concept
1081 ;; of a LET much more useful at the level of IR1 semantics. The
1082 ;; :ASSIGNMENT function kind provides another way to optimize
1083 ;; calls to single-return/multiple call functions.
1085 ;; We don't attempt to convert calls to functions that have an
1086 ;; XEP, since we might be embarrassed later when we want to
1087 ;; convert a newly discovered local call. Also, see
1088 ;; OK-INITIAL-CONVERT-P.
1089 (let ((refs (leaf-refs clambda
)))
1092 (memq (functional-kind clambda
) '(nil :assignment
))
1093 (not (functional-entry-fun clambda
)))
1094 (binding* ((ref (first refs
))
1095 (ref-lvar (node-lvar ref
) :exit-if-null
)
1096 (dest (lvar-dest ref-lvar
)))
1097 (when (and (basic-combination-p dest
)
1098 (eq (basic-combination-fun dest
) ref-lvar
)
1099 (eq (basic-combination-kind dest
) :local
)
1100 (not (node-to-be-deleted-p dest
))
1101 (not (block-delete-p (lambda-block clambda
)))
1102 (cond ((ok-initial-convert-p clambda
) t
)
1104 (reoptimize-lvar ref-lvar
)
1106 (when (eq clambda
(node-home-lambda dest
))
1107 (delete-lambda clambda
)
1108 (return-from maybe-let-convert nil
))
1109 (unless (eq (functional-kind clambda
) :assignment
)
1110 (let-convert clambda dest
))
1111 (reoptimize-call dest
)
1112 (setf (functional-kind clambda
)
1113 (if (mv-combination-p dest
) :mv-let
:let
))))
1116 ;;;; tail local calls and assignments
1118 ;;; Return T if there are no cleanups between BLOCK1 and BLOCK2, or if
1119 ;;; they definitely won't generate any cleanup code. Currently we
1120 ;;; recognize lexical entry points that are only used locally (if at
1122 (defun only-harmless-cleanups (block1 block2
)
1123 (declare (type cblock block1 block2
))
1124 (or (eq block1 block2
)
1125 (let ((cleanup2 (block-start-cleanup block2
)))
1126 (do ((cleanup (block-end-cleanup block1
)
1127 (node-enclosing-cleanup (cleanup-mess-up cleanup
))))
1128 ((eq cleanup cleanup2
) t
)
1129 (case (cleanup-kind cleanup
)
1131 (unless (null (entry-exits (cleanup-mess-up cleanup
)))
1133 (t (return nil
)))))))
1135 ;;; If a potentially TR local call really is TR, then convert it to
1136 ;;; jump directly to the called function. We also call
1137 ;;; MAYBE-CONVERT-TO-ASSIGNMENT. The first value is true if we
1138 ;;; tail-convert. The second is the value of M-C-T-A.
1139 (defun maybe-convert-tail-local-call (call)
1140 (declare (type combination call
))
1141 (let ((return (lvar-dest (node-lvar call
)))
1142 (fun (combination-lambda call
)))
1143 (aver (return-p return
))
1144 (when (and (not (node-tail-p call
)) ; otherwise already converted
1145 ;; this is a tail call
1146 (immediately-used-p (return-result return
) call
)
1147 (only-harmless-cleanups (node-block call
)
1148 (node-block return
))
1149 ;; If the call is in an XEP, we might decide to make it
1150 ;; non-tail so that we can use known return inside the
1152 (not (eq (functional-kind (node-home-lambda call
))
1154 (not (block-delete-p (lambda-block fun
))))
1155 (node-ends-block call
)
1156 (let ((block (node-block call
)))
1157 (setf (node-tail-p call
) t
)
1158 (unlink-blocks block
(first (block-succ block
)))
1159 (link-blocks block
(lambda-block fun
))
1160 (delete-lvar-use call
)
1161 (values t
(maybe-convert-to-assignment fun
))))))
1163 ;;; This is called when we believe it might make sense to convert
1164 ;;; CLAMBDA to an assignment. All this function really does is
1165 ;;; determine when a function with more than one call can still be
1166 ;;; combined with the calling function's environment. We can convert
1168 ;;; -- The function is a normal, non-entry function, and
1169 ;;; -- Except for one call, all calls must be tail recursive calls
1170 ;;; in the called function (i.e. are self-recursive tail calls)
1171 ;;; -- OK-INITIAL-CONVERT-P is true.
1173 ;;; There may be one outside call, and it need not be tail-recursive.
1174 ;;; Since all tail local calls have already been converted to direct
1175 ;;; transfers, the only control semantics needed are to splice in the
1176 ;;; body at the non-tail call. If there is no non-tail call, then we
1177 ;;; need only merge the environments. Both cases are handled by
1180 ;;; ### It would actually be possible to allow any number of outside
1181 ;;; calls as long as they all return to the same place (i.e. have the
1182 ;;; same conceptual continuation.) A special case of this would be
1183 ;;; when all of the outside calls are tail recursive.
1184 (defun maybe-convert-to-assignment (clambda)
1185 (declare (type clambda clambda
))
1186 (when (and (not (functional-kind clambda
))
1187 (not (functional-entry-fun clambda
))
1188 (not (functional-has-external-references-p clambda
)))
1189 (let ((outside-non-tail-call nil
)
1191 (when (and (dolist (ref (leaf-refs clambda
) t
)
1192 (let ((dest (node-dest ref
)))
1193 (when (or (not dest
)
1194 (block-delete-p (node-block dest
)))
1196 (let ((home (node-home-lambda ref
)))
1197 (unless (eq home clambda
)
1200 (setq outside-call dest
))
1201 (unless (node-tail-p dest
)
1202 (when (or outside-non-tail-call
(eq home clambda
))
1204 (setq outside-non-tail-call dest
)))))
1205 (ok-initial-convert-p clambda
))
1206 (cond (outside-call (setf (functional-kind clambda
) :assignment
)
1207 (let-convert clambda outside-call
)
1208 (when outside-non-tail-call
1209 (reoptimize-call outside-non-tail-call
))
1211 (t (delete-lambda clambda
)