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 (node-ends-block uses
))
53 ;; If this LVAR's USE is good for DX, it must be a regular
54 ;; combination, and its arguments are potentially DX as well.
56 (loop for arg in
(combination-args use
)
57 append
(handle-nested-dynamic-extent-lvars arg
))))
61 when
(use-good-for-dx-p use
)
63 (when (use-good-for-dx-p uses
)
66 (defun recognize-dynamic-extent-lvars (call fun
)
67 (declare (type combination call
) (type clambda fun
))
68 (loop for arg in
(basic-combination-args call
)
69 and var in
(lambda-vars fun
)
70 when
(and arg
(lambda-var-dynamic-extent var
)
71 (not (lvar-dynamic-extent arg
)))
72 append
(handle-nested-dynamic-extent-lvars arg
) into dx-lvars
73 finally
(when dx-lvars
74 (binding* ((before-ctran (node-prev call
))
75 (nil (ensure-block-start before-ctran
))
76 (block (ctran-block before-ctran
))
77 (new-call-ctran (make-ctran :kind
:inside-block
80 (entry (with-ir1-environment-from-node call
81 (make-entry :prev before-ctran
82 :next new-call-ctran
)))
83 (cleanup (make-cleanup :kind
:dynamic-extent
86 (setf (node-prev call
) new-call-ctran
)
87 (setf (ctran-next before-ctran
) entry
)
88 (setf (ctran-use new-call-ctran
) entry
)
89 (setf (entry-cleanup entry
) cleanup
)
90 (setf (node-lexenv call
)
91 (make-lexenv :default
(node-lexenv call
)
93 (push entry
(lambda-entries (node-home-lambda entry
)))
94 (dolist (lvar dx-lvars
)
95 (setf (lvar-dynamic-extent lvar
) cleanup
)))))
98 ;;; This function handles merging the tail sets if CALL is potentially
99 ;;; tail-recursive, and is a call to a function with a different
100 ;;; TAIL-SET than CALL's FUN. This must be called whenever we alter
101 ;;; IR1 so as to place a local call in what might be a tail-recursive
102 ;;; context. Note that any call which returns its value to a RETURN is
103 ;;; considered potentially tail-recursive, since any implicit MV-PROG1
104 ;;; might be optimized away.
106 ;;; We destructively modify the set for the calling function to
107 ;;; represent both, and then change all the functions in callee's set
108 ;;; to reference the first. If we do merge, we reoptimize the
109 ;;; RETURN-RESULT lvar to cause IR1-OPTIMIZE-RETURN to recompute the
111 (defun merge-tail-sets (call &optional
(new-fun (combination-lambda call
)))
112 (declare (type basic-combination call
) (type clambda new-fun
))
113 (let ((return (node-dest call
)))
114 (when (return-p return
)
115 (let ((call-set (lambda-tail-set (node-home-lambda call
)))
116 (fun-set (lambda-tail-set new-fun
)))
117 (unless (eq call-set fun-set
)
118 (let ((funs (tail-set-funs fun-set
)))
120 (setf (lambda-tail-set fun
) call-set
))
121 (setf (tail-set-funs call-set
)
122 (nconc (tail-set-funs call-set
) funs
)))
123 (reoptimize-lvar (return-result return
))
126 ;;; Convert a combination into a local call. We PROPAGATE-TO-ARGS, set
127 ;;; the combination kind to :LOCAL, add FUN to the CALLS of the
128 ;;; function that the call is in, call MERGE-TAIL-SETS, then replace
129 ;;; the function in the REF node with the new function.
131 ;;; We change the REF last, since changing the reference can trigger
132 ;;; LET conversion of the new function, but will only do so if the
133 ;;; call is local. Note that the replacement may trigger LET
134 ;;; conversion or other changes in IR1. We must call MERGE-TAIL-SETS
135 ;;; with NEW-FUN before the substitution, since after the substitution
136 ;;; (and LET conversion), the call may no longer be recognizable as
138 (defun convert-call (ref call fun
)
139 (declare (type ref ref
) (type combination call
) (type clambda fun
))
140 (propagate-to-args call fun
)
141 (setf (basic-combination-kind call
) :local
)
142 (unless (call-full-like-p call
)
143 (dolist (arg (basic-combination-args call
))
145 (flush-lvar-externally-checkable-type arg
))))
146 (sset-adjoin fun
(lambda-calls-or-closes (node-home-lambda call
)))
147 (recognize-dynamic-extent-lvars call fun
)
148 (merge-tail-sets call fun
)
149 (change-ref-leaf ref fun
)
152 ;;;; external entry point creation
154 ;;; Return a LAMBDA form that can be used as the definition of the XEP
157 ;;; If FUN is a LAMBDA, then we check the number of arguments
158 ;;; (conditional on policy) and call FUN with all the arguments.
160 ;;; If FUN is an OPTIONAL-DISPATCH, then we dispatch off of the number
161 ;;; of supplied arguments by doing do an = test for each entry-point,
162 ;;; calling the entry with the appropriate prefix of the passed
165 ;;; If there is a &MORE arg, then there are a couple of optimizations
166 ;;; that we make (more for space than anything else):
167 ;;; -- If MIN-ARGS is 0, then we make the more entry a T clause, since
168 ;;; no argument count error is possible.
169 ;;; -- We can omit the = clause for the last entry-point, allowing the
170 ;;; case of 0 more args to fall through to the more entry.
172 ;;; We don't bother to policy conditionalize wrong arg errors in
173 ;;; optional dispatches, since the additional overhead is negligible
174 ;;; compared to the cost of everything else going on.
176 ;;; Note that if policy indicates it, argument type declarations in
177 ;;; FUN will be verified. Since nothing is known about the type of the
178 ;;; XEP arg vars, type checks will be emitted when the XEP's arg vars
179 ;;; are passed to the actual function.
180 (defun make-xep-lambda-expression (fun)
181 (declare (type functional fun
))
184 (let ((nargs (length (lambda-vars fun
)))
185 (n-supplied (gensym))
186 (temps (make-gensym-list (length (lambda-vars fun
)))))
187 `(lambda (,n-supplied
,@temps
)
188 (declare (type index
,n-supplied
))
189 ,(if (policy *lexenv
* (zerop verify-arg-count
))
190 `(declare (ignore ,n-supplied
))
191 `(%verify-arg-count
,n-supplied
,nargs
))
193 (declare (optimize (merge-tail-calls 3)))
194 (%funcall
,fun
,@temps
)))))
196 (let* ((min (optional-dispatch-min-args fun
))
197 (max (optional-dispatch-max-args fun
))
198 (more (optional-dispatch-more-entry fun
))
199 (n-supplied (gensym))
200 (temps (make-gensym-list max
)))
202 ;; Force convertion of all entries
203 (optional-dispatch-entry-point-fun fun
0)
204 (loop for ep in
(optional-dispatch-entry-points fun
)
206 do
(entries `((eql ,n-supplied
,n
)
207 (%funcall
,(force ep
) ,@(subseq temps
0 n
)))))
208 `(lambda (,n-supplied
,@temps
)
209 ;; FIXME: Make sure that INDEX type distinguishes between
210 ;; target and host. (Probably just make the SB!XC:DEFTYPE
211 ;; different from CL:DEFTYPE.)
212 (declare (type index
,n-supplied
))
214 ,@(if more
(butlast (entries)) (entries))
216 ;; KLUDGE: (NOT (< ...)) instead of >= avoids one round of
217 ;; deftransforms and lambda-conversion.
218 `((,(if (zerop min
) t
`(not (< ,n-supplied
,max
)))
219 ,(let ((n-context (gensym))
221 `(multiple-value-bind (,n-context
,n-count
)
222 (%more-arg-context
,n-supplied
,max
)
224 (declare (optimize (merge-tail-calls 3)))
225 (%funcall
,more
,@temps
,n-context
,n-count
)))))))
227 (%arg-count-error
,n-supplied
)))))))))
229 ;;; Make an external entry point (XEP) for FUN and return it. We
230 ;;; convert the result of MAKE-XEP-LAMBDA in the correct environment,
231 ;;; then associate this lambda with FUN as its XEP. After the
232 ;;; conversion, we iterate over the function's associated lambdas,
233 ;;; redoing local call analysis so that the XEP calls will get
236 ;;; We set REANALYZE and REOPTIMIZE in the component, just in case we
237 ;;; discover an XEP after the initial local call analyze pass.
238 (defun make-xep (fun)
239 (declare (type functional fun
))
240 (aver (null (functional-entry-fun fun
)))
241 (with-ir1-environment-from-node (lambda-bind (main-entry fun
))
242 (let ((res (ir1-convert-lambda (make-xep-lambda-expression fun
)
243 :debug-name
(debug-name
244 'xep
(leaf-debug-name fun
)))))
245 (setf (functional-kind res
) :external
246 (leaf-ever-used res
) t
247 (functional-entry-fun res
) fun
248 (functional-entry-fun fun
) res
249 (component-reanalyze *current-component
*) t
)
250 (reoptimize-component *current-component
* :maybe
)
253 (locall-analyze-fun-1 fun
))
255 (dolist (ep (optional-dispatch-entry-points fun
))
256 (locall-analyze-fun-1 (force ep
)))
257 (when (optional-dispatch-more-entry fun
)
258 (locall-analyze-fun-1 (optional-dispatch-more-entry fun
)))))
261 ;;; Notice a REF that is not in a local-call context. If the REF is
262 ;;; already to an XEP, then do nothing, otherwise change it to the
263 ;;; XEP, making an XEP if necessary.
265 ;;; If REF is to a special :CLEANUP or :ESCAPE function, then we treat
266 ;;; it as though it was not an XEP reference (i.e. leave it alone).
267 (defun reference-entry-point (ref)
268 (declare (type ref ref
))
269 (let ((fun (ref-leaf ref
)))
270 (unless (or (xep-p fun
)
271 (member (functional-kind fun
) '(:escape
:cleanup
)))
272 (change-ref-leaf ref
(or (functional-entry-fun fun
)
275 ;;; Attempt to convert all references to FUN to local calls. The
276 ;;; reference must be the function for a call, and the function lvar
277 ;;; must be used only once, since otherwise we cannot be sure what
278 ;;; function is to be called. The call lvar would be multiply used if
279 ;;; there is hairy stuff such as conditionals in the expression that
280 ;;; computes the function.
282 ;;; If we cannot convert a reference, then we mark the referenced
283 ;;; function as an entry-point, creating a new XEP if necessary. We
284 ;;; don't try to convert calls that are in error (:ERROR kind.)
286 ;;; This is broken off from LOCALL-ANALYZE-COMPONENT so that people
287 ;;; can force analysis of newly introduced calls. Note that we don't
288 ;;; do LET conversion here.
289 (defun locall-analyze-fun-1 (fun)
290 (declare (type functional fun
))
291 (let ((refs (leaf-refs fun
))
294 (let* ((lvar (node-lvar ref
))
295 (dest (when lvar
(lvar-dest lvar
))))
296 (unless (node-to-be-deleted-p ref
)
297 (cond ((and (basic-combination-p dest
)
298 (eq (basic-combination-fun dest
) lvar
)
299 (eq (lvar-uses lvar
) ref
))
301 (convert-call-if-possible ref dest
)
303 (unless (eq (basic-combination-kind dest
) :local
)
304 (reference-entry-point ref
)
307 (reference-entry-point ref
)
308 (setq local-p nil
))))))
309 (when local-p
(note-local-functional fun
)))
313 ;;; We examine all NEW-FUNCTIONALS in COMPONENT, attempting to convert
314 ;;; calls into local calls when it is legal. We also attempt to
315 ;;; convert each LAMBDA to a LET. LET conversion is also triggered by
316 ;;; deletion of a function reference, but functions that start out
317 ;;; eligible for conversion must be noticed sometime.
319 ;;; Note that there is a lot of action going on behind the scenes
320 ;;; here, triggered by reference deletion. In particular, the
321 ;;; COMPONENT-LAMBDAS are being hacked to remove newly deleted and LET
322 ;;; converted LAMBDAs, so it is important that the LAMBDA is added to
323 ;;; the COMPONENT-LAMBDAS when it is. Also, the
324 ;;; COMPONENT-NEW-FUNCTIONALS may contain all sorts of drivel, since
325 ;;; it is not updated when we delete functions, etc. Only
326 ;;; COMPONENT-LAMBDAS is updated.
328 ;;; COMPONENT-REANALYZE-FUNCTIONALS is treated similarly to
329 ;;; COMPONENT-NEW-FUNCTIONALS, but we don't add lambdas to the
331 (defun locall-analyze-component (component)
332 (declare (type component component
))
333 (aver-live-component component
)
335 (let* ((new-functional (pop (component-new-functionals component
)))
336 (functional (or new-functional
337 (pop (component-reanalyze-functionals component
)))))
340 (let ((kind (functional-kind functional
)))
341 (cond ((or (functional-somewhat-letlike-p functional
)
342 (memq kind
'(:deleted
:zombie
)))
343 (values)) ; nothing to do
344 ((and (null (leaf-refs functional
)) (eq kind nil
)
345 (not (functional-entry-fun functional
)))
346 (delete-functional functional
))
348 ;; Fix/check FUNCTIONAL's relationship to COMPONENT-LAMDBAS.
349 (cond ((not (lambda-p functional
))
350 ;; Since FUNCTIONAL isn't a LAMBDA, this doesn't
353 (new-functional ; FUNCTIONAL came from
354 ; NEW-FUNCTIONALS, hence is new.
355 ;; FUNCTIONAL becomes part of COMPONENT-LAMBDAS now.
356 (aver (not (member functional
357 (component-lambdas component
))))
358 (push functional
(component-lambdas component
)))
359 (t ; FUNCTIONAL is old.
360 ;; FUNCTIONAL should be in COMPONENT-LAMBDAS already.
361 (aver (member functional
(component-lambdas
363 (locall-analyze-fun-1 functional
)
364 (when (lambda-p functional
)
365 (maybe-let-convert functional
)))))))
368 (defun locall-analyze-clambdas-until-done (clambdas)
370 (let ((did-something nil
))
371 (dolist (clambda clambdas
)
372 (let ((component (lambda-component clambda
)))
373 ;; The original CMU CL code seemed to implicitly assume that
374 ;; COMPONENT is the only one here. Let's make that explicit.
375 (aver (= 1 (length (functional-components clambda
))))
376 (aver (eql component
(first (functional-components clambda
))))
377 (when (or (component-new-functionals component
)
378 (component-reanalyze-functionals component
))
379 (setf did-something t
)
380 (locall-analyze-component component
))))
381 (unless did-something
385 ;;; If policy is auspicious and CALL is not in an XEP and we don't seem
386 ;;; to be in an infinite recursive loop, then change the reference to
387 ;;; reference a fresh copy. We return whichever function we decide to
389 (defun maybe-expand-local-inline (original-functional ref call
)
390 (if (and (policy call
391 (and (>= speed space
)
392 (>= speed compilation-speed
)))
393 (not (eq (functional-kind (node-home-lambda call
)) :external
))
394 (inline-expansion-ok call
))
395 (let* ((end (component-last-block (node-component call
)))
396 (pred (block-prev end
)))
397 (multiple-value-bind (losing-local-object converted-lambda
)
398 (catch 'locall-already-let-converted
399 (with-ir1-environment-from-node call
400 (let ((*lexenv
* (functional-lexenv original-functional
)))
403 (functional-inline-expansion original-functional
)
404 :debug-name
(debug-name 'local-inline
406 original-functional
)))))))
407 (cond (losing-local-object
408 (if (functional-p losing-local-object
)
409 (let ((*compiler-error-context
* call
))
410 (compiler-notify "couldn't inline expand because expansion ~
411 calls this LET-converted local function:~
413 (leaf-debug-name losing-local-object
)))
414 (let ((*compiler-error-context
* call
))
415 (compiler-notify "implementation limitation: couldn't inline ~
416 expand because expansion refers to ~
417 the optimized away object ~S."
418 losing-local-object
)))
419 (loop for block
= (block-next pred
) then
(block-next block
)
421 do
(setf (block-delete-p block
) t
))
422 (loop for block
= (block-next pred
) then
(block-next block
)
424 do
(delete-block block t
))
427 (change-ref-leaf ref converted-lambda
)
429 original-functional
))
431 ;;; Dispatch to the appropriate function to attempt to convert a call.
432 ;;; REF must be a reference to a FUNCTIONAL. This is called in IR1
433 ;;; optimization as well as in local call analysis. If the call is is
434 ;;; already :LOCAL, we do nothing. If the call is already scheduled
435 ;;; for deletion, also do nothing (in addition to saving time, this
436 ;;; also avoids some problems with optimizing collections of functions
437 ;;; that are partially deleted.)
439 ;;; This is called both before and after FIND-INITIAL-DFO runs. When
440 ;;; called on a :INITIAL component, we don't care whether the caller
441 ;;; and callee are in the same component. Afterward, we must stick
442 ;;; with whatever component division we have chosen.
444 ;;; Before attempting to convert a call, we see whether the function
445 ;;; is supposed to be inline expanded. Call conversion proceeds as
446 ;;; before after any expansion.
448 ;;; We bind *COMPILER-ERROR-CONTEXT* to the node for the call so that
449 ;;; warnings will get the right context.
450 (defun convert-call-if-possible (ref call
)
451 (declare (type ref ref
) (type basic-combination call
))
452 (let* ((block (node-block call
))
453 (component (block-component block
))
454 (original-fun (ref-leaf ref
)))
455 (aver (functional-p original-fun
))
456 (unless (or (member (basic-combination-kind call
) '(:local
:error
))
457 (node-to-be-deleted-p call
)
458 (member (functional-kind original-fun
)
459 '(:toplevel-xep
:deleted
))
460 (not (or (eq (component-kind component
) :initial
)
463 (lambda-bind (main-entry original-fun
))))
465 (let ((fun (if (xep-p original-fun
)
466 (functional-entry-fun original-fun
)
468 (*compiler-error-context
* call
))
470 (when (and (eq (functional-inlinep fun
) :inline
)
471 (rest (leaf-refs original-fun
)))
472 (setq fun
(maybe-expand-local-inline fun ref call
)))
474 (aver (member (functional-kind fun
)
475 '(nil :escape
:cleanup
:optional
)))
476 (cond ((mv-combination-p call
)
477 (convert-mv-call ref call fun
))
479 (convert-lambda-call ref call fun
))
481 (convert-hairy-call ref call fun
))))))
485 ;;; Attempt to convert a multiple-value call. The only interesting
486 ;;; case is a call to a function that LOOKS-LIKE-AN-MV-BIND, has
487 ;;; exactly one reference and no XEP, and is called with one values
490 ;;; We change the call to be to the last optional entry point and
491 ;;; change the call to be local. Due to our preconditions, the call
492 ;;; should eventually be converted to a let, but we can't do that now,
493 ;;; since there may be stray references to the e-p lambda due to
494 ;;; optional defaulting code.
496 ;;; We also use variable types for the called function to construct an
497 ;;; assertion for the values lvar.
499 ;;; See CONVERT-CALL for additional notes on MERGE-TAIL-SETS, etc.
500 (defun convert-mv-call (ref call fun
)
501 (declare (type ref ref
) (type mv-combination call
) (type functional fun
))
502 (when (and (looks-like-an-mv-bind fun
)
503 (singleton-p (leaf-refs fun
))
504 (singleton-p (basic-combination-args call
)))
505 (let* ((*current-component
* (node-component ref
))
506 (ep (optional-dispatch-entry-point-fun
507 fun
(optional-dispatch-max-args fun
))))
508 (when (null (leaf-refs ep
))
509 (aver (= (optional-dispatch-min-args fun
) 0))
510 (aver (not (functional-entry-fun fun
)))
511 (setf (basic-combination-kind call
) :local
)
512 (sset-adjoin ep
(lambda-calls-or-closes (node-home-lambda call
)))
513 (merge-tail-sets call ep
)
514 (change-ref-leaf ref ep
)
517 (first (basic-combination-args call
))
518 (make-short-values-type (mapcar #'leaf-type
(lambda-vars ep
)))
519 (lexenv-policy (node-lexenv call
))))))
522 ;;; Attempt to convert a call to a lambda. If the number of args is
523 ;;; wrong, we give a warning and mark the call as :ERROR to remove it
524 ;;; from future consideration. If the argcount is O.K. then we just
526 (defun convert-lambda-call (ref call fun
)
527 (declare (type ref ref
) (type combination call
) (type clambda fun
))
528 (let ((nargs (length (lambda-vars fun
)))
529 (n-call-args (length (combination-args call
))))
530 (cond ((= n-call-args nargs
)
531 (convert-call ref call fun
))
534 'local-argument-mismatch
536 "function called with ~R argument~:P, but wants exactly ~R"
537 :format-arguments
(list n-call-args nargs
))
538 (setf (basic-combination-kind call
) :error
)))))
540 ;;;; &OPTIONAL, &MORE and &KEYWORD calls
542 ;;; This is similar to CONVERT-LAMBDA-CALL, but deals with
543 ;;; OPTIONAL-DISPATCHes. If only fixed args are supplied, then convert
544 ;;; a call to the correct entry point. If &KEY args are supplied, then
545 ;;; dispatch to a subfunction. We don't convert calls to functions
546 ;;; that have a &MORE (or &REST) arg.
547 (defun convert-hairy-call (ref call fun
)
548 (declare (type ref ref
) (type combination call
)
549 (type optional-dispatch fun
))
550 (let ((min-args (optional-dispatch-min-args fun
))
551 (max-args (optional-dispatch-max-args fun
))
552 (call-args (length (combination-args call
))))
553 (cond ((< call-args min-args
)
555 'local-argument-mismatch
557 "function called with ~R argument~:P, but wants at least ~R"
558 :format-arguments
(list call-args min-args
))
559 (setf (basic-combination-kind call
) :error
))
560 ((<= call-args max-args
)
561 (convert-call ref call
562 (let ((*current-component
* (node-component ref
)))
563 (optional-dispatch-entry-point-fun
564 fun
(- call-args min-args
)))))
565 ((optional-dispatch-more-entry fun
)
566 (convert-more-call ref call fun
))
569 'local-argument-mismatch
571 "function called with ~R argument~:P, but wants at most ~R"
573 (list call-args max-args
))
574 (setf (basic-combination-kind call
) :error
))))
577 ;;; This function is used to convert a call to an entry point when
578 ;;; complex transformations need to be done on the original arguments.
579 ;;; ENTRY is the entry point function that we are calling. VARS is a
580 ;;; list of variable names which are bound to the original call
581 ;;; arguments. IGNORES is the subset of VARS which are ignored. ARGS
582 ;;; is the list of arguments to the entry point function.
584 ;;; In order to avoid gruesome graph grovelling, we introduce a new
585 ;;; function that rearranges the arguments and calls the entry point.
586 ;;; We analyze the new function and the entry point immediately so
587 ;;; that everything gets converted during the single pass.
588 (defun convert-hairy-fun-entry (ref call entry vars ignores args
)
589 (declare (list vars ignores args
) (type ref ref
) (type combination call
)
590 (type clambda entry
))
592 (with-ir1-environment-from-node call
595 (declare (ignorable ,@ignores
))
596 (%funcall
,entry
,@args
))
597 :debug-name
(debug-name 'hairy-function-entry
599 (basic-combination-fun call
)))))))
600 (convert-call ref call new-fun
)
601 (dolist (ref (leaf-refs entry
))
602 (convert-call-if-possible ref
(lvar-dest (node-lvar ref
))))))
604 ;;; Use CONVERT-HAIRY-FUN-ENTRY to convert a &MORE-arg call to a known
605 ;;; function into a local call to the MAIN-ENTRY.
607 ;;; First we verify that all keywords are constant and legal. If there
608 ;;; aren't, then we warn the user and don't attempt to convert the call.
610 ;;; We massage the supplied &KEY arguments into the order expected
611 ;;; by the main entry. This is done by binding all the arguments to
612 ;;; the keyword call to variables in the introduced lambda, then
613 ;;; passing these values variables in the correct order when calling
614 ;;; the main entry. Unused arguments (such as the keywords themselves)
615 ;;; are discarded simply by not passing them along.
617 ;;; If there is a &REST arg, then we bundle up the args and pass them
619 (defun convert-more-call (ref call fun
)
620 (declare (type ref ref
) (type combination call
) (type optional-dispatch fun
))
621 (let* ((max (optional-dispatch-max-args fun
))
622 (arglist (optional-dispatch-arglist fun
))
623 (args (combination-args call
))
624 (more (nthcdr max args
))
625 (flame (policy call
(or (> speed inhibit-warnings
)
626 (> space inhibit-warnings
))))
630 (temps (make-gensym-list max
))
631 (more-temps (make-gensym-list (length more
))))
636 (dolist (var arglist
)
637 (let ((info (lambda-var-arg-info var
)))
639 (ecase (arg-info-kind info
)
643 ((:more-context
:more-count
)
644 (compiler-warn "can't local-call functions with &MORE args")
645 (setf (basic-combination-kind call
) :error
)
646 (return-from convert-more-call
))))))
648 (when (optional-dispatch-keyp fun
)
649 (when (oddp (length more
))
650 (compiler-warn "function called with odd number of ~
651 arguments in keyword portion")
652 (setf (basic-combination-kind call
) :error
)
653 (return-from convert-more-call
))
655 (do ((key more
(cddr key
))
656 (temp more-temps
(cddr temp
)))
658 (let ((lvar (first key
)))
659 (unless (constant-lvar-p lvar
)
661 (compiler-notify "non-constant keyword in keyword call"))
662 (setf (basic-combination-kind call
) :error
)
663 (return-from convert-more-call
))
665 (let ((name (lvar-value lvar
))
668 (when (and (eq name
:allow-other-keys
) (not allow-found
))
669 (let ((val (second key
)))
670 (cond ((constant-lvar-p val
)
672 allowp
(lvar-value val
)))
674 (compiler-notify "non-constant :ALLOW-OTHER-KEYS value"))
675 (setf (basic-combination-kind call
) :error
)
676 (return-from convert-more-call
)))))
677 (dolist (var (key-vars)
680 (unless (eq name
:allow-other-keys
)
681 (setq loser
(list name
)))))
682 (let ((info (lambda-var-arg-info var
)))
683 (when (eq (arg-info-key info
) name
)
685 (if (member var
(supplied) :key
#'car
)
687 (supplied (cons var val
)))
690 (when (and loser
(not (optional-dispatch-allowp fun
)) (not allowp
))
691 (compiler-warn "function called with unknown argument keyword ~S"
693 (setf (basic-combination-kind call
) :error
)
694 (return-from convert-more-call
)))
696 (collect ((call-args))
697 (do ((var arglist
(cdr var
))
698 (temp temps
(cdr temp
)))
700 (let ((info (lambda-var-arg-info (car var
))))
702 (ecase (arg-info-kind info
)
704 (call-args (car temp
))
705 (when (arg-info-supplied-p info
)
708 (call-args `(list ,@more-temps
))
712 (call-args (car temp
)))))
714 (dolist (var (key-vars))
715 (let ((info (lambda-var-arg-info var
))
716 (temp (cdr (assoc var
(supplied)))))
719 (call-args (arg-info-default info
)))
720 (when (arg-info-supplied-p info
)
721 (call-args (not (null temp
))))))
723 (convert-hairy-fun-entry ref call
(optional-dispatch-main-entry fun
)
724 (append temps more-temps
)
725 (ignores) (call-args)))))
731 ;;;; Converting to a LET has differing significance to various parts
732 ;;;; of the compiler:
733 ;;;; -- The body of a LET is spliced in immediately after the
734 ;;;; corresponding combination node, making the control transfer
735 ;;;; explicit and allowing LETs to be mashed together into a single
736 ;;;; block. The value of the LET is delivered directly to the
737 ;;;; original lvar for the call, eliminating the need to
738 ;;;; propagate information from the dummy result lvar.
739 ;;;; -- As far as IR1 optimization is concerned, it is interesting in
740 ;;;; that there is only one expression that the variable can be bound
741 ;;;; to, and this is easily substituted for.
742 ;;;; -- LETs are interesting to environment analysis and to the back
743 ;;;; end because in most ways a LET can be considered to be "the
744 ;;;; same function" as its home function.
745 ;;;; -- LET conversion has dynamic scope implications, since control
746 ;;;; transfers within the same environment are local. In a local
747 ;;;; control transfer, cleanup code must be emitted to remove
748 ;;;; dynamic bindings that are no longer in effect.
750 ;;; Set up the control transfer to the called CLAMBDA. We split the
751 ;;; call block immediately after the call, and link the head of
752 ;;; CLAMBDA to the call block. The successor block after splitting
753 ;;; (where we return to) is returned.
755 ;;; If the lambda is is a different component than the call, then we
756 ;;; call JOIN-COMPONENTS. This only happens in block compilation
757 ;;; before FIND-INITIAL-DFO.
758 (defun insert-let-body (clambda call
)
759 (declare (type clambda clambda
) (type basic-combination call
))
760 (let* ((call-block (node-block call
))
761 (bind-block (node-block (lambda-bind clambda
)))
762 (component (block-component call-block
)))
763 (aver-live-component component
)
764 (let ((clambda-component (block-component bind-block
)))
765 (unless (eq clambda-component component
)
766 (aver (eq (component-kind component
) :initial
))
767 (join-components component clambda-component
)))
768 (let ((*current-component
* component
))
769 (node-ends-block call
))
770 (destructuring-bind (next-block)
771 (block-succ call-block
)
772 (unlink-blocks call-block next-block
)
773 (link-blocks call-block bind-block
)
776 ;;; Remove CLAMBDA from the tail set of anything it used to be in the
777 ;;; same set as; but leave CLAMBDA with a valid tail set value of
778 ;;; its own, for the benefit of code which might try to pull
779 ;;; something out of it (e.g. return type).
780 (defun depart-from-tail-set (clambda)
781 ;; Until sbcl-0.pre7.37.flaky5.2, we did
782 ;; (LET ((TAILS (LAMBDA-TAIL-SET CLAMBDA)))
783 ;; (SETF (TAIL-SET-FUNS TAILS)
784 ;; (DELETE CLAMBDA (TAIL-SET-FUNS TAILS))))
785 ;; (SETF (LAMBDA-TAIL-SET CLAMBDA) NIL)
786 ;; here. Apparently the idea behind the (SETF .. NIL) was that since
787 ;; TAIL-SET-FUNS no longer thinks we're in the tail set, it's
788 ;; inconsistent, and perhaps unsafe, for us to think we're in the
789 ;; tail set. Unfortunately..
791 ;; The (SETF .. NIL) caused problems in sbcl-0.pre7.37.flaky5.2 when
792 ;; I was trying to get Python to emit :EXTERNAL LAMBDAs directly
793 ;; (instead of only being able to emit funny little :TOPLEVEL stubs
794 ;; which you called in order to get the address of an external LAMBDA):
795 ;; the external function was defined in terms of internal function,
796 ;; which was LET-converted, and then things blew up downstream when
797 ;; FINALIZE-XEP-DEFINITION tried to find out its DEFINED-TYPE from
798 ;; the now-NILed-out TAIL-SET. So..
800 ;; To deal with this problem, we no longer NIL out
801 ;; (LAMBDA-TAIL-SET CLAMBDA) here. Instead:
802 ;; * If we're the only function in TAIL-SET-FUNS, it should
803 ;; be safe to leave ourself linked to it, and it to you.
804 ;; * If there are other functions in TAIL-SET-FUNS, then we're
805 ;; afraid of future optimizations on those functions causing
806 ;; the TAIL-SET object no longer to be valid to describe our
807 ;; return value. Thus, we delete ourselves from that object;
808 ;; but we save a newly-allocated tail-set, derived from the old
809 ;; one, for ourselves, for the use of later code (e.g.
810 ;; FINALIZE-XEP-DEFINITION) which might want to
811 ;; know about our return type.
812 (let* ((old-tail-set (lambda-tail-set clambda
))
813 (old-tail-set-funs (tail-set-funs old-tail-set
)))
814 (unless (= 1 (length old-tail-set-funs
))
815 (setf (tail-set-funs old-tail-set
)
816 (delete clambda old-tail-set-funs
))
817 (let ((new-tail-set (copy-tail-set old-tail-set
)))
818 (setf (lambda-tail-set clambda
) new-tail-set
819 (tail-set-funs new-tail-set
) (list clambda
)))))
820 ;; The documentation on TAIL-SET-INFO doesn't tell whether it could
821 ;; remain valid in this case, so we nuke it on the theory that
822 ;; missing information tends to be less dangerous than incorrect
824 (setf (tail-set-info (lambda-tail-set clambda
)) nil
))
826 ;;; Handle the PHYSENV semantics of LET conversion. We add CLAMBDA and
827 ;;; its LETs to LETs for the CALL's home function. We merge the calls
828 ;;; for CLAMBDA with the calls for the home function, removing CLAMBDA
829 ;;; in the process. We also merge the ENTRIES.
831 ;;; We also unlink the function head from the component head and set
832 ;;; COMPONENT-REANALYZE to true to indicate that the DFO should be
834 (defun merge-lets (clambda call
)
836 (declare (type clambda clambda
) (type basic-combination call
))
838 (let ((component (node-component call
)))
839 (unlink-blocks (component-head component
) (lambda-block clambda
))
840 (setf (component-lambdas component
)
841 (delete clambda
(component-lambdas component
)))
842 (setf (component-reanalyze component
) t
))
843 (setf (lambda-call-lexenv clambda
) (node-lexenv call
))
845 (depart-from-tail-set clambda
)
847 (let* ((home (node-home-lambda call
))
848 (home-physenv (lambda-physenv home
))
849 (physenv (lambda-physenv clambda
)))
851 (aver (not (eq home clambda
)))
853 ;; CLAMBDA belongs to HOME now.
854 (push clambda
(lambda-lets home
))
855 (setf (lambda-home clambda
) home
)
856 (setf (lambda-physenv clambda
) home-physenv
)
859 (setf (physenv-nlx-info home-physenv
)
860 (nconc (physenv-nlx-info physenv
)
861 (physenv-nlx-info home-physenv
))))
863 ;; All of CLAMBDA's LETs belong to HOME now.
864 (let ((lets (lambda-lets clambda
)))
866 (setf (lambda-home let
) home
)
867 (setf (lambda-physenv let
) home-physenv
))
868 (setf (lambda-lets home
) (nconc lets
(lambda-lets home
))))
869 ;; CLAMBDA no longer has an independent existence as an entity
871 (setf (lambda-lets clambda
) nil
)
873 ;; HOME no longer calls CLAMBDA, and owns all of CLAMBDA's old
875 (sset-union (lambda-calls-or-closes home
)
876 (lambda-calls-or-closes clambda
))
877 (sset-delete clambda
(lambda-calls-or-closes home
))
878 ;; CLAMBDA no longer has an independent existence as an entity
879 ;; which calls things or has DFO dependencies.
880 (setf (lambda-calls-or-closes clambda
) nil
)
882 ;; All of CLAMBDA's ENTRIES belong to HOME now.
883 (setf (lambda-entries home
)
884 (nconc (lambda-entries clambda
)
885 (lambda-entries home
)))
886 ;; CLAMBDA no longer has an independent existence as an entity
888 (setf (lambda-entries clambda
) nil
))
892 ;;; Handle the value semantics of LET conversion. Delete FUN's return
893 ;;; node, and change the control flow to transfer to NEXT-BLOCK
894 ;;; instead. Move all the uses of the result lvar to CALL's lvar.
895 (defun move-return-uses (fun call next-block
)
896 (declare (type clambda fun
) (type basic-combination call
)
897 (type cblock next-block
))
898 (let* ((return (lambda-return fun
))
900 (ensure-block-start (node-prev return
))
901 (node-block return
))))
902 (unlink-blocks return-block
903 (component-tail (block-component return-block
)))
904 (link-blocks return-block next-block
)
906 (delete-return return
)
907 (let ((result (return-result return
))
908 (lvar (if (node-tail-p call
)
909 (return-result (lambda-return (node-home-lambda call
)))
911 (call-type (node-derived-type call
)))
912 (unless (eq call-type
*wild-type
*)
913 ;; FIXME: Replace the call with unsafe CAST. -- APD, 2003-01-26
914 (do-uses (use result
)
915 (derive-node-type use call-type
)))
916 (substitute-lvar-uses lvar result
917 (and lvar
(eq (lvar-uses lvar
) call
)))))
920 ;;; We are converting FUN to be a LET when the call is in a non-tail
921 ;;; position. Any previously tail calls in FUN are no longer tail
922 ;;; calls, and must be restored to normal calls which transfer to
923 ;;; NEXT-BLOCK (FUN's return point.) We can't do this by DO-USES on
924 ;;; the RETURN-RESULT, because the return might have been deleted (if
925 ;;; all calls were TR.)
926 (defun unconvert-tail-calls (fun call next-block
)
927 (do-sset-elements (called (lambda-calls-or-closes fun
))
928 (when (lambda-p called
)
929 (dolist (ref (leaf-refs called
))
930 (let ((this-call (node-dest ref
)))
932 (node-tail-p this-call
)
933 (eq (node-home-lambda this-call
) fun
))
934 (setf (node-tail-p this-call
) nil
)
935 (ecase (functional-kind called
)
936 ((nil :cleanup
:optional
)
937 (let ((block (node-block this-call
))
938 (lvar (node-lvar call
)))
939 (unlink-blocks block
(first (block-succ block
)))
940 (link-blocks block next-block
)
941 (aver (not (node-lvar this-call
)))
942 (add-lvar-use this-call lvar
)))
944 ;; The called function might be an assignment in the
945 ;; case where we are currently converting that function.
946 ;; In steady-state, assignments never appear as a called
949 (aver (eq called fun
)))))))))
952 ;;; Deal with returning from a LET or assignment that we are
953 ;;; converting. FUN is the function we are calling, CALL is a call to
954 ;;; FUN, and NEXT-BLOCK is the return point for a non-tail call, or
955 ;;; NULL if call is a tail call.
957 ;;; If the call is not a tail call, then we must do
958 ;;; UNCONVERT-TAIL-CALLS, since a tail call is a call which returns
959 ;;; its value out of the enclosing non-let function. When call is
960 ;;; non-TR, we must convert it back to an ordinary local call, since
961 ;;; the value must be delivered to the receiver of CALL's value.
963 ;;; We do different things depending on whether the caller and callee
964 ;;; have returns left:
966 ;;; -- If the callee has no return we just do MOVE-LET-CALL-CONT.
967 ;;; Either the function doesn't return, or all returns are via
968 ;;; tail-recursive local calls.
969 ;;; -- If CALL is a non-tail call, or if both have returns, then
970 ;;; we delete the callee's return, move its uses to the call's
971 ;;; result lvar, and transfer control to the appropriate
973 ;;; -- If the callee has a return, but the caller doesn't, then we
974 ;;; move the return to the caller.
975 (defun move-return-stuff (fun call next-block
)
976 (declare (type clambda fun
) (type basic-combination call
)
977 (type (or cblock null
) next-block
))
979 (unconvert-tail-calls fun call next-block
))
980 (let* ((return (lambda-return fun
))
981 (call-fun (node-home-lambda call
))
982 (call-return (lambda-return call-fun
)))
983 (when (and call-return
984 (block-delete-p (node-block call-return
)))
985 (delete-return call-return
)
986 (unlink-node call-return
)
987 (setq call-return nil
))
989 ((or next-block call-return
)
990 (unless (block-delete-p (node-block return
))
992 (ensure-block-start (node-prev call-return
))
993 (setq next-block
(node-block call-return
)))
994 (move-return-uses fun call next-block
)))
996 (aver (node-tail-p call
))
997 (setf (lambda-return call-fun
) return
)
998 (setf (return-lambda return
) call-fun
)
999 (setf (lambda-return fun
) nil
))))
1000 (%delete-lvar-use call
) ; LET call does not have value semantics
1003 ;;; Actually do LET conversion. We call subfunctions to do most of the
1004 ;;; work. We do REOPTIMIZE-LVAR on the args and CALL's lvar so that
1005 ;;; LET-specific IR1 optimizations get a chance. We blow away any
1006 ;;; entry for the function in *FREE-FUNS* so that nobody will create
1007 ;;; new references to it.
1008 (defun let-convert (fun call
)
1009 (declare (type clambda fun
) (type basic-combination call
))
1010 (let* ((next-block (insert-let-body fun call
))
1011 (next-block (if (node-tail-p call
)
1014 (move-return-stuff fun call next-block
)
1015 (merge-lets fun call
)
1016 (setf (node-tail-p call
) nil
)
1017 ;; If CALL has a derive type NIL, it means that "its return" is
1018 ;; unreachable, but the next BIND is still reachable; in order to
1019 ;; not confuse MAYBE-TERMINATE-BLOCK...
1020 (setf (node-derived-type call
) *wild-type
*)))
1022 ;;; Reoptimize all of CALL's args and its result.
1023 (defun reoptimize-call (call)
1024 (declare (type basic-combination call
))
1025 (dolist (arg (basic-combination-args call
))
1027 (reoptimize-lvar arg
)))
1028 (reoptimize-lvar (node-lvar call
))
1031 ;;; Are there any declarations in force to say CLAMBDA shouldn't be
1033 (defun declarations-suppress-let-conversion-p (clambda)
1034 ;; From the user's point of view, LET-converting something that
1035 ;; has a name is inlining it. (The user can't see what we're doing
1036 ;; with anonymous things, and suppressing inlining
1037 ;; for such things can easily give Python acute indigestion, so
1039 (when (leaf-has-source-name-p clambda
)
1040 ;; ANSI requires that explicit NOTINLINE be respected.
1041 (or (eq (lambda-inlinep clambda
) :notinline
)
1042 ;; If (= LET-CONVERSION 0) we can guess that inlining
1043 ;; generally won't be appreciated, but if the user
1044 ;; specifically requests inlining, that takes precedence over
1045 ;; our general guess.
1046 (and (policy clambda
(= let-conversion
0))
1047 (not (eq (lambda-inlinep clambda
) :inline
))))))
1049 ;;; We also don't convert calls to named functions which appear in the
1050 ;;; initial component, delaying this until optimization. This
1051 ;;; minimizes the likelihood that we will LET-convert a function which
1052 ;;; may have references added due to later local inline expansion.
1053 (defun ok-initial-convert-p (fun)
1054 (not (and (leaf-has-source-name-p fun
)
1055 (or (declarations-suppress-let-conversion-p fun
)
1056 (eq (component-kind (lambda-component fun
))
1059 ;;; This function is called when there is some reason to believe that
1060 ;;; CLAMBDA might be converted into a LET. This is done after local
1061 ;;; call analysis, and also when a reference is deleted. We return
1062 ;;; true if we converted.
1063 (defun maybe-let-convert (clambda)
1064 (declare (type clambda clambda
))
1065 (unless (or (declarations-suppress-let-conversion-p clambda
)
1066 (functional-has-external-references-p clambda
))
1067 ;; We only convert to a LET when the function is a normal local
1068 ;; function, has no XEP, and is referenced in exactly one local
1069 ;; call. Conversion is also inhibited if the only reference is in
1070 ;; a block about to be deleted.
1072 ;; These rules limiting LET conversion may seem unnecessarily
1073 ;; restrictive, since there are some cases where we could do the
1074 ;; return with a jump that don't satisfy these requirements. The
1075 ;; reason for doing things this way is that it makes the concept
1076 ;; of a LET much more useful at the level of IR1 semantics. The
1077 ;; :ASSIGNMENT function kind provides another way to optimize
1078 ;; calls to single-return/multiple call functions.
1080 ;; We don't attempt to convert calls to functions that have an
1081 ;; XEP, since we might be embarrassed later when we want to
1082 ;; convert a newly discovered local call. Also, see
1083 ;; OK-INITIAL-CONVERT-P.
1084 (let ((refs (leaf-refs clambda
)))
1087 (memq (functional-kind clambda
) '(nil :assignment
))
1088 (not (functional-entry-fun clambda
)))
1089 (binding* ((ref (first refs
))
1090 (ref-lvar (node-lvar ref
) :exit-if-null
)
1091 (dest (lvar-dest ref-lvar
)))
1092 (when (and (basic-combination-p dest
)
1093 (eq (basic-combination-fun dest
) ref-lvar
)
1094 (eq (basic-combination-kind dest
) :local
)
1095 (not (node-to-be-deleted-p dest
))
1096 (not (block-delete-p (lambda-block clambda
)))
1097 (cond ((ok-initial-convert-p clambda
) t
)
1099 (reoptimize-lvar ref-lvar
)
1101 (when (eq clambda
(node-home-lambda dest
))
1102 (delete-lambda clambda
)
1103 (return-from maybe-let-convert nil
))
1104 (unless (eq (functional-kind clambda
) :assignment
)
1105 (let-convert clambda dest
))
1106 (reoptimize-call dest
)
1107 (setf (functional-kind clambda
)
1108 (if (mv-combination-p dest
) :mv-let
:let
))))
1111 ;;;; tail local calls and assignments
1113 ;;; Return T if there are no cleanups between BLOCK1 and BLOCK2, or if
1114 ;;; they definitely won't generate any cleanup code. Currently we
1115 ;;; recognize lexical entry points that are only used locally (if at
1117 (defun only-harmless-cleanups (block1 block2
)
1118 (declare (type cblock block1 block2
))
1119 (or (eq block1 block2
)
1120 (let ((cleanup2 (block-start-cleanup block2
)))
1121 (do ((cleanup (block-end-cleanup block1
)
1122 (node-enclosing-cleanup (cleanup-mess-up cleanup
))))
1123 ((eq cleanup cleanup2
) t
)
1124 (case (cleanup-kind cleanup
)
1126 (unless (null (entry-exits (cleanup-mess-up cleanup
)))
1128 (t (return nil
)))))))
1130 ;;; If a potentially TR local call really is TR, then convert it to
1131 ;;; jump directly to the called function. We also call
1132 ;;; MAYBE-CONVERT-TO-ASSIGNMENT. The first value is true if we
1133 ;;; tail-convert. The second is the value of M-C-T-A.
1134 (defun maybe-convert-tail-local-call (call)
1135 (declare (type combination call
))
1136 (let ((return (lvar-dest (node-lvar call
)))
1137 (fun (combination-lambda call
)))
1138 (aver (return-p return
))
1139 (when (and (not (node-tail-p call
)) ; otherwise already converted
1140 ;; this is a tail call
1141 (immediately-used-p (return-result return
) call
)
1142 (only-harmless-cleanups (node-block call
)
1143 (node-block return
))
1144 ;; If the call is in an XEP, we might decide to make it
1145 ;; non-tail so that we can use known return inside the
1147 (not (eq (functional-kind (node-home-lambda call
))
1149 (not (block-delete-p (lambda-block fun
))))
1150 (node-ends-block call
)
1151 (let ((block (node-block call
)))
1152 (setf (node-tail-p call
) t
)
1153 (unlink-blocks block
(first (block-succ block
)))
1154 (link-blocks block
(lambda-block fun
))
1155 (delete-lvar-use call
)
1156 (values t
(maybe-convert-to-assignment fun
))))))
1158 ;;; This is called when we believe it might make sense to convert
1159 ;;; CLAMBDA to an assignment. All this function really does is
1160 ;;; determine when a function with more than one call can still be
1161 ;;; combined with the calling function's environment. We can convert
1163 ;;; -- The function is a normal, non-entry function, and
1164 ;;; -- Except for one call, all calls must be tail recursive calls
1165 ;;; in the called function (i.e. are self-recursive tail calls)
1166 ;;; -- OK-INITIAL-CONVERT-P is true.
1168 ;;; There may be one outside call, and it need not be tail-recursive.
1169 ;;; Since all tail local calls have already been converted to direct
1170 ;;; transfers, the only control semantics needed are to splice in the
1171 ;;; body at the non-tail call. If there is no non-tail call, then we
1172 ;;; need only merge the environments. Both cases are handled by
1175 ;;; ### It would actually be possible to allow any number of outside
1176 ;;; calls as long as they all return to the same place (i.e. have the
1177 ;;; same conceptual continuation.) A special case of this would be
1178 ;;; when all of the outside calls are tail recursive.
1179 (defun maybe-convert-to-assignment (clambda)
1180 (declare (type clambda clambda
))
1181 (when (and (not (functional-kind clambda
))
1182 (not (functional-entry-fun clambda
))
1183 (not (functional-has-external-references-p clambda
)))
1184 (let ((outside-non-tail-call nil
)
1186 (when (and (dolist (ref (leaf-refs clambda
) t
)
1187 (let ((dest (node-dest ref
)))
1188 (when (or (not dest
)
1189 (block-delete-p (node-block dest
)))
1191 (let ((home (node-home-lambda ref
)))
1192 (unless (eq home clambda
)
1195 (setq outside-call dest
))
1196 (unless (node-tail-p dest
)
1197 (when (or outside-non-tail-call
(eq home clambda
))
1199 (setq outside-non-tail-call dest
)))))
1200 (ok-initial-convert-p clambda
))
1201 (cond (outside-call (setf (functional-kind clambda
) :assignment
)
1202 (let-convert clambda outside-call
)
1203 (when outside-non-tail-call
1204 (reoptimize-call outside-non-tail-call
))
1206 (t (delete-lambda clambda
)