/[cmucl]/src/compiler/locall.lisp
ViewVC logotype

Contents of /src/compiler/locall.lisp

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1.38 - (hide annotations)
Tue Sep 22 14:10:07 1992 UTC (21 years, 7 months ago) by ram
Branch: MAIN
Changes since 1.37: +43 -24 lines
Inhibit assignment conversion (as well as let conversion) in calls to named
local functions in the initial component.  When converting an assignment to a
let, don't do LET-CONVERT again, because we've already done it, just
reoptimize.
1 wlott 1.1 ;;; -*- Package: C; Log: C.Log -*-
2     ;;;
3     ;;; **********************************************************************
4 ram 1.15 ;;; This code was written as part of the CMU Common Lisp project at
5     ;;; Carnegie Mellon University, and has been placed in the public domain.
6     ;;; If you want to use this code or any part of CMU Common Lisp, please contact
7     ;;; Scott Fahlman or slisp-group@cs.cmu.edu.
8     ;;;
9     (ext:file-comment
10 ram 1.38 "$Header: /tiger/var/lib/cvsroots/cmucl/src/compiler/locall.lisp,v 1.38 1992/09/22 14:10:07 ram Exp $")
11 ram 1.15 ;;;
12 wlott 1.1 ;;; **********************************************************************
13     ;;;
14     ;;; This file implements local call analysis. A local call is a function
15     ;;; call between functions being compiled at the same time. If we can tell at
16 ram 1.9 ;;; compile time that such a call is legal, then we change the combination
17     ;;; to call the correct lambda, mark it as local, and add this link to our call
18     ;;; graph. Once a call is local, it is then eligible for let conversion, which
19     ;;; places the body of the function inline.
20 wlott 1.1 ;;;
21     ;;; We cannot always do a local call even when we do have the function being
22 ram 1.35 ;;; called. Calls that cannot be shown to have legal arg counts are not
23     ;;; converted.
24 wlott 1.1 ;;;
25     ;;; Written by Rob MacLachlan
26     ;;;
27 ram 1.31 (in-package :c)
28 wlott 1.1
29    
30 ram 1.11 ;;; Propagate-To-Args -- Interface
31 wlott 1.1 ;;;
32     ;;; This function propagates information from the variables in the function
33 ram 1.11 ;;; Fun to the actual arguments in Call. This is also called by the VALUES IR1
34     ;;; optimizer when it sleazily converts MV-BINDs to LETs.
35 wlott 1.1 ;;;
36     ;;; We flush all arguments to Call that correspond to unreferenced variables
37     ;;; in Fun. We leave NILs in the Combination-Args so that the remaining args
38     ;;; still match up with their vars.
39     ;;;
40     ;;; We also apply the declared variable type assertion to the argument
41     ;;; continuations.
42     ;;;
43     (defun propagate-to-args (call fun)
44     (declare (type combination call) (type clambda fun))
45     (do ((args (basic-combination-args call) (cdr args))
46     (vars (lambda-vars fun) (cdr vars)))
47     ((null args))
48     (let ((arg (car args))
49     (var (car vars)))
50     (cond ((leaf-refs var)
51     (assert-continuation-type arg (leaf-type var)))
52     (t
53     (flush-dest arg)
54     (setf (car args) nil)))))
55    
56     (undefined-value))
57    
58    
59 ram 1.31 ;;; Merge-Tail-Sets -- Interface
60     ;;;
61     ;;; This function handles merging the tail sets if Call is potentially
62     ;;; tail-recursive, and is a call to a function with a different TAIL-SET than
63     ;;; Call's Fun. This must be called whenever we alter IR1 so as to place a
64     ;;; local call in what might be a TR context. Note that any call which returns
65     ;;; its value to a RETURN is considered potentially TR, since any implicit
66     ;;; MV-PROG1 might be optimized away.
67     ;;;
68     ;;; We destructively modify the set for the calling function to represent both,
69     ;;; and then change all the functions in callee's set to reference the first.
70     ;;; If we do merge, we reoptimize the RETURN-RESULT continuation to cause
71     ;;; IR1-OPTIMIZE-RETURN to recompute the tail set type.
72     ;;;
73 ram 1.33 (defun merge-tail-sets (call &optional (new-fun (combination-lambda call)))
74     (declare (type basic-combination call) (type clambda new-fun))
75 ram 1.31 (let ((return (continuation-dest (node-cont call))))
76     (when (return-p return)
77     (let ((call-set (lambda-tail-set (node-home-lambda call)))
78 ram 1.33 (fun-set (lambda-tail-set new-fun)))
79 ram 1.31 (unless (eq call-set fun-set)
80     (let ((funs (tail-set-functions fun-set)))
81     (dolist (fun funs)
82     (setf (lambda-tail-set fun) call-set))
83     (setf (tail-set-functions call-set)
84     (nconc (tail-set-functions call-set) funs)))
85     (reoptimize-continuation (return-result return))
86     t)))))
87    
88    
89 wlott 1.1 ;;; Convert-Call -- Internal
90     ;;;
91 ram 1.31 ;;; Convert a combination into a local call. We PROPAGATE-TO-ARGS, set the
92 wlott 1.1 ;;; combination kind to :Local, add Fun to the Calls of the function that the
93 ram 1.33 ;;; call is in, call MERGE-TAIL-SETS, then replace the function in the Ref node
94     ;;; with the new function.
95 wlott 1.1 ;;;
96 ram 1.33 ;;; We change the Ref last, since changing the reference can trigger let
97 wlott 1.1 ;;; conversion of the new function, but will only do so if the call is local.
98 ram 1.33 ;;; Note that the replacement may trigger let conversion or other changes in
99     ;;; IR1. We must call MERGE-TAIL-SETS with NEW-FUN before the substitution,
100     ;;; since after the substitution (and let conversion), the call may no longer
101     ;;; be recognizable as tail-recursive.
102 wlott 1.1 ;;;
103     (defun convert-call (ref call fun)
104     (declare (type ref ref) (type combination call) (type clambda fun))
105     (propagate-to-args call fun)
106     (setf (basic-combination-kind call) :local)
107 ram 1.6 (pushnew fun (lambda-calls (node-home-lambda call)))
108 ram 1.33 (merge-tail-sets call fun)
109 wlott 1.1 (change-ref-leaf ref fun)
110     (undefined-value))
111    
112    
113     ;;;; External entry point creation:
114    
115     ;;; Make-XEP-Lambda -- Internal
116     ;;;
117     ;;; Return a Lambda form that can be used as the definition of the XEP for
118     ;;; Fun.
119     ;;;
120     ;;; If Fun is a lambda, then we check the number of arguments (conditional
121     ;;; on policy) and call Fun with all the arguments.
122     ;;;
123     ;;; If Fun is an Optional-Dispatch, then we dispatch off of the number of
124     ;;; supplied arguments by doing do an = test for each entry-point, calling the
125     ;;; entry with the appropriate prefix of the passed arguments.
126     ;;;
127     ;;; If there is a more arg, then there are a couple of optimizations that we
128     ;;; make (more for space than anything else):
129     ;;; -- If Min-Args is 0, then we make the more entry a T clause, since no
130     ;;; argument count error is possible.
131     ;;; -- We can omit the = clause for the last entry-point, allowing the case of
132     ;;; 0 more args to fall through to the more entry.
133     ;;;
134     ;;; We don't bother to policy conditionalize wrong arg errors in optional
135     ;;; dispatches, since the additional overhead is negligible compared to the
136     ;;; other hair going down.
137     ;;;
138     ;;; Note that if policy indicates it, argument type declarations in Fun will
139     ;;; be verified. Since nothing is known about the type of the XEP arg vars,
140     ;;; type checks will be emitted when the XEP's arg vars are passed to the
141     ;;; actual function.
142     ;;;
143     (defun make-xep-lambda (fun)
144     (declare (type functional fun))
145     (etypecase fun
146     (clambda
147     (let ((nargs (length (lambda-vars fun)))
148     (n-supplied (gensym)))
149     (collect ((temps))
150     (dotimes (i nargs)
151     (temps (gensym)))
152     `(lambda (,n-supplied ,@(temps))
153     (declare (fixnum ,n-supplied))
154 ram 1.35 ,(if (policy nil (zerop safety))
155 wlott 1.1 `(declare (ignore ,n-supplied))
156     `(%verify-argument-count ,n-supplied ,nargs))
157     (%funcall ,fun ,@(temps))))))
158     (optional-dispatch
159     (let* ((min (optional-dispatch-min-args fun))
160     (max (optional-dispatch-max-args fun))
161     (more (optional-dispatch-more-entry fun))
162     (n-supplied (gensym)))
163     (collect ((temps)
164     (entries))
165     (dotimes (i max)
166     (temps (gensym)))
167    
168     (do ((eps (optional-dispatch-entry-points fun) (rest eps))
169     (n min (1+ n)))
170     ((null eps))
171     (entries `((= ,n-supplied ,n)
172     (%funcall ,(first eps) ,@(subseq (temps) 0 n)))))
173    
174     `(lambda (,n-supplied ,@(temps))
175     (declare (fixnum ,n-supplied))
176     (cond
177     ,@(if more (butlast (entries)) (entries))
178     ,@(when more
179     `((,(if (zerop min) 't `(>= ,n-supplied ,max))
180     ,(let ((n-context (gensym))
181     (n-count (gensym)))
182     `(multiple-value-bind
183     (,n-context ,n-count)
184     (%more-arg-context ,n-supplied ,max)
185     (%funcall ,more ,@(temps) ,n-context ,n-count))))))
186     (t
187     (%argument-count-error ,n-supplied)))))))))
188    
189    
190     ;;; Make-External-Entry-Point -- Internal
191     ;;;
192     ;;; Make an external entry point (XEP) for Fun and return it. We convert
193     ;;; the result of Make-XEP-Lambda in the correct environment, then associate
194     ;;; this lambda with Fun as its XEP. After the conversion, we iterate over the
195     ;;; function's associated lambdas, redoing local call analysis so that the XEP
196 ram 1.18 ;;; calls will get converted. We also bind *lexical-environment* to change the
197     ;;; compilation policy over to the interface policy.
198 wlott 1.1 ;;;
199     ;;; We set Reanalyze and Reoptimize in the component, just in case we
200     ;;; discover an XEP after the initial local call analyze pass.
201     ;;;
202     (defun make-external-entry-point (fun)
203     (declare (type functional fun))
204     (assert (not (functional-entry-function fun)))
205     (with-ir1-environment (lambda-bind (main-entry fun))
206 ram 1.18 (let* ((*lexical-environment*
207     (make-lexenv :cookie
208     (make-interface-cookie *lexical-environment*)))
209     (res (ir1-convert-lambda (make-xep-lambda fun))))
210 wlott 1.1 (setf (functional-kind res) :external)
211 ram 1.12 (setf (leaf-ever-used res) t)
212 wlott 1.1 (setf (functional-entry-function res) fun)
213     (setf (functional-entry-function fun) res)
214     (setf (component-reanalyze *current-component*) t)
215     (setf (component-reoptimize *current-component*) t)
216     (etypecase fun
217     (clambda (local-call-analyze-1 fun))
218     (optional-dispatch
219     (dolist (ep (optional-dispatch-entry-points fun))
220     (local-call-analyze-1 ep))
221     (when (optional-dispatch-more-entry fun)
222     (local-call-analyze-1 (optional-dispatch-more-entry fun)))))
223     res)))
224    
225    
226     ;;; Reference-Entry-Point -- Internal
227     ;;;
228     ;;; Notice a Ref that is not in a local-call context. If the Ref is already
229     ;;; to an XEP, then do nothing, otherwise change it to the XEP, making an XEP
230     ;;; if necessary.
231     ;;;
232     ;;; If Ref is to a special :Cleanup or :Escape function, then we treat it as
233     ;;; though it was not an XEP reference (i.e. leave it alone.)
234     ;;;
235     (defun reference-entry-point (ref)
236     (declare (type ref ref))
237     (let ((fun (ref-leaf ref)))
238     (unless (or (external-entry-point-p fun)
239     (member (functional-kind fun) '(:escape :cleanup)))
240     (change-ref-leaf ref (or (functional-entry-function fun)
241     (make-external-entry-point fun))))))
242    
243 ram 1.35
244 wlott 1.1
245     ;;; Local-Call-Analyze-1 -- Interface
246     ;;;
247     ;;; Attempt to convert all references to Fun to local calls. The reference
248 ram 1.35 ;;; must be the function for a call, and the function continuation must be used
249     ;;; only once, since otherwise we cannot be sure what function is to be called.
250     ;;; The call continuation would be multiply used if there is hairy stuff such
251     ;;; as conditionals in the expression that computes the function.
252 wlott 1.1 ;;;
253     ;;; If we cannot convert a reference, then we mark the referenced function
254 ram 1.35 ;;; as an entry-point, creating a new XEP if necessary. We don't try to
255     ;;; convert calls that are in error (:ERROR kind.)
256 wlott 1.1 ;;;
257     ;;; This is broken off from Local-Call-Analyze so that people can force
258     ;;; analysis of newly introduced calls. Note that we don't do let conversion
259     ;;; here.
260     ;;;
261     (defun local-call-analyze-1 (fun)
262     (declare (type functional fun))
263 ram 1.35 (let ((refs (leaf-refs fun))
264     (first-time t))
265 ram 1.3 (dolist (ref refs)
266     (let* ((cont (node-cont ref))
267     (dest (continuation-dest cont)))
268     (cond ((and (basic-combination-p dest)
269     (eq (basic-combination-fun dest) cont)
270 ram 1.35 (eq (continuation-use cont) ref))
271    
272     (convert-call-if-possible ref dest)
273 ram 1.3
274     (unless (eq (basic-combination-kind dest) :local)
275     (reference-entry-point ref)))
276     (t
277 ram 1.35 (reference-entry-point ref))))
278     (setq first-time nil)))
279 wlott 1.1
280     (undefined-value))
281    
282    
283     ;;; Local-Call-Analyze -- Interface
284     ;;;
285     ;;; We examine all New-Functions in component, attempting to convert calls
286     ;;; into local calls when it is legal. We also attempt to convert each lambda
287     ;;; to a let. Let conversion is also triggered by deletion of a function
288     ;;; reference, but functions that start out eligible for conversion must be
289     ;;; noticed sometime.
290     ;;;
291     ;;; Note that there is a lot of action going on behind the scenes here,
292     ;;; triggered by reference deletion. In particular, the Component-Lambdas are
293     ;;; being hacked to remove newly deleted and let converted lambdas, so it is
294     ;;; important that the lambda is added to the Component-Lambdas when it is.
295 ram 1.37 ;;; Also, the COMPONENT-NEW-FUNCTIONS may contain all sorts of drivel, since it
296 ram 1.35 ;;; is not updated when we delete functions, etc. Only COMPONENT-LAMBDAS is
297     ;;; updated.
298 wlott 1.1 ;;;
299 ram 1.37 ;;; COMPONENT-REANALYZE-FUNCTIONS is treated similarly to NEW-FUNCTIONS, but we
300     ;;; don't add lambdas to the LAMBDAS.
301     ;;;
302 wlott 1.1 (defun local-call-analyze (component)
303     (declare (type component component))
304     (loop
305 ram 1.37 (let* ((new (pop (component-new-functions component)))
306     (fun (or new (pop (component-reanalyze-functions component)))))
307     (unless fun (return))
308     (let ((kind (functional-kind fun)))
309     (cond ((member kind '(:deleted :let :mv-let :assignment)))
310     ((and (null (leaf-refs fun)) (eq kind nil)
311     (not (functional-entry-function fun)))
312     (delete-functional fun))
313     (t
314     (when (and new (lambda-p fun))
315     (push fun (component-lambdas component)))
316     (local-call-analyze-1 fun)
317     (when (lambda-p fun)
318     (maybe-let-convert fun)))))))
319 ram 1.17
320 wlott 1.1 (undefined-value))
321    
322    
323 ram 1.35 ;;; MAYBE-EXPAND-LOCAL-INLINE -- Internal
324     ;;;
325     ;;; If policy is auspicious, Call is not in an XEP, and we don't seem to be
326     ;;; in an infinite recursive loop, then change the reference to reference a
327     ;;; fresh copy. We return whichever function we decide to reference.
328     ;;;
329     (defun maybe-expand-local-inline (fun ref call)
330     (if (and (policy call (>= speed space) (>= speed cspeed))
331     (not (eq (functional-kind (node-home-lambda call)) :external))
332     (inline-expansion-ok call))
333     (with-ir1-environment call
334     (let* ((*lexical-environment* (functional-lexenv fun))
335 ram 1.36 (won nil)
336     (res (catch 'local-call-lossage
337     (prog1
338     (ir1-convert-lambda (functional-inline-expansion fun))
339     (setq won t)))))
340     (cond (won
341     (change-ref-leaf ref res)
342     res)
343     (t
344     (let ((*compiler-error-context* call))
345     (compiler-note "Couldn't inline expand because expansion ~
346     calls this let-converted local function:~
347     ~% ~S"
348     (leaf-name res)))
349     fun))))
350 ram 1.35 fun))
351    
352    
353 wlott 1.1 ;;; Convert-Call-If-Possible -- Interface
354     ;;;
355     ;;; Dispatch to the appropriate function to attempt to convert a call. This
356     ;;; is called in IR1 optimize as well as in local call analysis. If the call
357 ram 1.35 ;;; is is already :Local, we do nothing. If the call is already scheduled for
358     ;;; deletion, also do nothing (in addition to saving time, this also avoids
359     ;;; some problems with optimizing collections of functions that are partially
360     ;;; deleted.)
361 wlott 1.1 ;;;
362 ram 1.35 ;;; This is called both before and after FIND-INITIAL-DFO runs. When called
363     ;;; on a :INITIAL component, we don't care whether the caller and callee are in
364     ;;; the same component. Afterward, we must stick with whatever component
365     ;;; division we have chosen.
366     ;;;
367     ;;; Before attempting to convert a call, we see if the function is supposed
368     ;;; to be inline expanded. Call conversion proceeds as before after any
369     ;;; expansion.
370     ;;;
371 wlott 1.1 ;;; We bind *Compiler-Error-Context* to the node for the call so that
372     ;;; warnings will get the right context.
373     ;;;
374 ram 1.35 ;;;
375 wlott 1.1 (defun convert-call-if-possible (ref call)
376     (declare (type ref ref) (type basic-combination call))
377 ram 1.35 (let* ((block (node-block call))
378     (component (block-component block))
379     (original-fun (ref-leaf ref)))
380     (unless (or (member (basic-combination-kind call) '(:local :error))
381     (block-delete-p block)
382     (eq (functional-kind (block-home-lambda block)) :deleted)
383     (not (or (eq (component-kind component) :initial)
384     (eq (block-component
385     (node-block
386     (lambda-bind (main-entry original-fun))))
387     component))))
388     (let ((fun (if (external-entry-point-p original-fun)
389     (functional-entry-function original-fun)
390     original-fun))
391     (*compiler-error-context* call))
392    
393     (when (and (eq (functional-inlinep fun) :inline)
394     (rest (leaf-refs original-fun)))
395     (setq fun (maybe-expand-local-inline fun ref call)))
396    
397     (assert (member (functional-kind fun)
398     '(nil :escape :cleanup :optional)))
399     (cond ((mv-combination-p call)
400     (convert-mv-call ref call fun))
401     ((lambda-p fun)
402     (convert-lambda-call ref call fun))
403     (t
404     (convert-hairy-call ref call fun))))))
405    
406 wlott 1.1 (undefined-value))
407    
408    
409     ;;; Convert-MV-Call -- Internal
410     ;;;
411     ;;; Attempt to convert a multiple-value call. The only interesting case is
412     ;;; a call to a function that Looks-Like-An-MV-Bind, has exactly one reference
413     ;;; and no XEP, and is called with one values continuation.
414     ;;;
415     ;;; We change the call to be to the last optional entry point and change the
416     ;;; call to be local. Due to our preconditions, the call should eventually be
417     ;;; converted to a let, but we can't do that now, since there may be stray
418     ;;; references to the e-p lambda due to optional defaulting code.
419     ;;;
420     ;;; We also use variable types for the called function to construct an
421     ;;; assertion for the values continuation.
422     ;;;
423 ram 1.34 ;;; See CONVERT-CALL for additional notes on MERGE-TAIL-SETS, etc.
424     ;;;
425 wlott 1.1 (defun convert-mv-call (ref call fun)
426     (declare (type ref ref) (type mv-combination call) (type functional fun))
427     (when (and (looks-like-an-mv-bind fun)
428     (not (functional-entry-function fun))
429     (= (length (leaf-refs fun)) 1)
430     (= (length (basic-combination-args call)) 1))
431     (let ((ep (car (last (optional-dispatch-entry-points fun)))))
432     (setf (basic-combination-kind call) :local)
433 ram 1.6 (pushnew ep (lambda-calls (node-home-lambda call)))
434 ram 1.34 (merge-tail-sets call ep)
435 ram 1.22 (change-ref-leaf ref ep)
436 ram 1.31
437 wlott 1.1 (assert-continuation-type
438     (first (basic-combination-args call))
439     (make-values-type :optional (mapcar #'leaf-type (lambda-vars ep))
440     :rest *universal-type*))))
441     (undefined-value))
442    
443    
444     ;;; Convert-Lambda-Call -- Internal
445     ;;;
446     ;;; Attempt to convert a call to a lambda. If the number of args is wrong,
447 ram 1.35 ;;; we give a warning and mark the call as :ERROR to remove it from future
448 wlott 1.1 ;;; consideration. If the argcount is O.K. then we just convert it.
449     ;;;
450     (defun convert-lambda-call (ref call fun)
451 ram 1.9 (declare (type ref ref) (type combination call) (type clambda fun))
452 wlott 1.1 (let ((nargs (length (lambda-vars fun)))
453     (call-args (length (combination-args call))))
454     (cond ((= call-args nargs)
455     (convert-call ref call fun))
456     (t
457     (compiler-warning
458     "Function called with ~R argument~:P, but wants exactly ~R."
459     call-args nargs)
460 ram 1.35 (setf (basic-combination-kind call) :error)))))
461 wlott 1.1
462    
463    
464     ;;;; Optional, more and keyword calls:
465    
466     ;;; Convert-Hairy-Call -- Internal
467     ;;;
468     ;;; Similar to Convert-Lambda-Call, but deals with Optional-Dispatches. If
469     ;;; only fixed args are supplied, then convert a call to the correct entry
470     ;;; point. If keyword args are supplied, then dispatch to a subfunction. We
471     ;;; don't convert calls to functions that have a more (or rest) arg.
472     ;;;
473     (defun convert-hairy-call (ref call fun)
474     (declare (type ref ref) (type combination call)
475     (type optional-dispatch fun))
476     (let ((min-args (optional-dispatch-min-args fun))
477     (max-args (optional-dispatch-max-args fun))
478     (call-args (length (combination-args call))))
479     (cond ((< call-args min-args)
480     (compiler-warning "Function called with ~R argument~:P, but wants at least ~R."
481     call-args min-args)
482 ram 1.35 (setf (basic-combination-kind call) :error))
483 wlott 1.1 ((<= call-args max-args)
484     (convert-call ref call
485     (elt (optional-dispatch-entry-points fun)
486     (- call-args min-args))))
487 ram 1.13 ((optional-dispatch-more-entry fun)
488     (convert-more-call ref call fun))
489     (t
490 wlott 1.1 (compiler-warning "Function called with ~R argument~:P, but wants at most ~R."
491     call-args max-args)
492 ram 1.35 (setf (basic-combination-kind call) :error))))
493 wlott 1.1 (undefined-value))
494    
495    
496     ;;; Convert-Hairy-Fun-Entry -- Internal
497     ;;;
498     ;;; This function is used to convert a call to an entry point when complex
499     ;;; transformations need to be done on the original arguments. Entry is the
500     ;;; entry point function that we are calling. Vars is a list of variable names
501     ;;; which are bound to the oringinal call arguments. Ignores is the subset of
502     ;;; Vars which are ignored. Args is the list of arguments to the entry point
503     ;;; function.
504     ;;;
505     ;;; In order to avoid gruesome graph grovelling, we introduce a new function
506     ;;; that rearranges the arguments and calls the entry point. We analyze the
507     ;;; new function and the entry point immediately so that everything gets
508     ;;; converted during the single pass.
509     ;;;
510     (defun convert-hairy-fun-entry (ref call entry vars ignores args)
511 ram 1.9 (declare (list vars ignores args) (type ref ref) (type combination call)
512     (type clambda entry))
513 wlott 1.1 (let ((new-fun
514     (with-ir1-environment call
515     (ir1-convert-lambda
516     `(lambda ,vars
517 ram 1.13 (declare (ignorable . ,ignores))
518 ram 1.6 (%funcall ,entry . ,args))))))
519 wlott 1.1 (convert-call ref call new-fun)
520     (dolist (ref (leaf-refs entry))
521     (convert-call-if-possible ref (continuation-dest (node-cont ref))))))
522    
523    
524 ram 1.13 ;;; Convert-More-Call -- Internal
525 wlott 1.1 ;;;
526 ram 1.13 ;;; Use Convert-Hairy-Fun-Entry to convert a more-arg call to a known
527     ;;; function into a local call to the Main-Entry.
528 wlott 1.1 ;;;
529     ;;; First we verify that all keywords are constant and legal. If there
530     ;;; aren't, then we warn the user and don't attempt to convert the call.
531     ;;;
532     ;;; We massage the supplied keyword arguments into the order expected by the
533     ;;; main entry. This is done by binding all the arguments to the keyword call
534     ;;; to variables in the introduced lambda, then passing these values variables
535     ;;; in the correct order when calling the main entry. Unused arguments
536     ;;; (such as the keywords themselves) are discarded simply by not passing them
537     ;;; along.
538     ;;;
539 ram 1.13 ;;; If there is a rest arg, then we bundle up the args and pass them to
540     ;;; LIST.
541     ;;;
542     (defun convert-more-call (ref call fun)
543 wlott 1.1 (declare (type ref ref) (type combination call) (type optional-dispatch fun))
544     (let* ((max (optional-dispatch-max-args fun))
545     (arglist (optional-dispatch-arglist fun))
546     (args (combination-args call))
547 ram 1.13 (more (nthcdr max args))
548 ram 1.11 (flame (policy call (or (> speed brevity) (> space brevity))))
549 wlott 1.1 (loser nil))
550     (collect ((temps)
551 ram 1.13 (more-temps)
552 wlott 1.1 (ignores)
553     (supplied)
554     (key-vars))
555    
556     (dolist (var arglist)
557     (let ((info (lambda-var-arg-info var)))
558     (when info
559     (ecase (arg-info-kind info)
560     (:keyword
561     (key-vars var))
562 ram 1.16 ((:rest :optional))))))
563 wlott 1.1
564     (dotimes (i max)
565 ram 1.13 (temps (gensym "FIXED-ARG-TEMP-")))
566 wlott 1.1
567 ram 1.13 (dotimes (i (length more))
568     (more-temps (gensym "MORE-ARG-TEMP-")))
569 wlott 1.1
570 ram 1.13 (when (optional-dispatch-keyp fun)
571     (when (oddp (length more))
572     (compiler-warning "Function called with odd number of ~
573     arguments in keyword portion.")
574 ram 1.35
575     (setf (basic-combination-kind call) :error)
576 ram 1.13 (return-from convert-more-call))
577    
578     (do ((key more (cddr key))
579     (temp (more-temps) (cddr temp)))
580     ((null key))
581     (let ((cont (first key)))
582     (unless (constant-continuation-p cont)
583     (when flame
584     (compiler-note "Non-constant keyword in keyword call."))
585 ram 1.35 (setf (basic-combination-kind call) :error)
586 ram 1.13 (return-from convert-more-call))
587    
588     (let ((name (continuation-value cont))
589     (dummy (first temp))
590     (val (second temp)))
591     (dolist (var (key-vars)
592     (progn
593     (ignores dummy val)
594     (setq loser name)))
595     (let ((info (lambda-var-arg-info var)))
596     (when (eq (arg-info-keyword info) name)
597 wlott 1.1 (ignores dummy)
598 ram 1.14 (supplied (cons var val))
599     (return)))))))
600 ram 1.13
601     (when (and loser (not (optional-dispatch-allowp fun)))
602     (compiler-warning "Function called with unknown argument keyword ~S."
603     loser)
604 ram 1.35 (setf (basic-combination-kind call) :error)
605 ram 1.13 (return-from convert-more-call)))
606 wlott 1.1
607     (collect ((call-args))
608     (do ((var arglist (cdr var))
609     (temp (temps) (cdr temp)))
610     (())
611     (let ((info (lambda-var-arg-info (car var))))
612     (if info
613 ram 1.13 (ecase (arg-info-kind info)
614 wlott 1.1 (:optional
615     (call-args (car temp))
616     (when (arg-info-supplied-p info)
617     (call-args t)))
618 ram 1.13 (:rest
619     (call-args `(list ,@(more-temps)))
620     (return))
621     (:keyword
622 wlott 1.1 (return)))
623     (call-args (car temp)))))
624    
625     (dolist (var (key-vars))
626     (let ((info (lambda-var-arg-info var))
627     (temp (cdr (assoc var (supplied)))))
628     (if temp
629     (call-args temp)
630     (call-args (arg-info-default info)))
631     (when (arg-info-supplied-p info)
632     (call-args (not (null temp))))))
633    
634     (convert-hairy-fun-entry ref call (optional-dispatch-main-entry fun)
635 ram 1.13 (append (temps) (more-temps))
636     (ignores) (call-args)))))
637 wlott 1.1
638     (undefined-value))
639    
640    
641     ;;;; Let conversion:
642     ;;;
643     ;;; Converting to a let has differing significance to various parts of the
644     ;;; compiler:
645     ;;; -- The body of a Let is spliced in immediately after the the corresponding
646     ;;; combination node, making the control transfer explicit and allowing lets
647     ;;; to mashed together into a single block. The value of the let is
648     ;;; delivered directly to the original continuation for the call,
649     ;;; eliminating the need to propagate information from the dummy result
650     ;;; continuation.
651     ;;; -- As far as IR1 optimization is concerned, it is interesting in that there
652     ;;; is only one expression that the variable can be bound to, and this is
653     ;;; easily substitited for.
654     ;;; -- Lets are interesting to environment analysis and the back end because in
655     ;;; most ways a let can be considered to be "the same function" as its home
656     ;;; function.
657     ;;; -- Let conversion has dynamic scope implications, since control transfers
658     ;;; within the same environment are local. In a local control transfer,
659     ;;; cleanup code must be emitted to remove dynamic bindings that are no
660     ;;; longer in effect.
661    
662    
663 ram 1.23 ;;; Insert-Let-Body -- Internal
664     ;;;
665     ;;; Set up the control transfer to the called lambda. We split the call
666     ;;; block immediately after the call, and link the head of Fun to the call
667     ;;; block. The successor block after splitting (where we return to) is
668     ;;; returned.
669     ;;;
670     ;;; If the lambda is is a different component than the call, then we call
671     ;;; JOIN-COMPONENTS. This only happens in block compilation before
672     ;;; FIND-INITIAL-DFO.
673     ;;;
674     (defun insert-let-body (fun call)
675     (declare (type clambda fun) (type basic-combination call))
676     (let* ((call-block (node-block call))
677     (bind-block (node-block (lambda-bind fun)))
678     (component (block-component call-block)))
679     (let ((fun-component (block-component bind-block)))
680     (unless (eq fun-component component)
681     (assert (eq (component-kind component) :initial))
682     (join-components component fun-component)))
683    
684     (let ((*current-component* component))
685     (node-ends-block call))
686     (assert (= (length (block-succ call-block)) 1))
687     (let ((next-block (first (block-succ call-block))))
688     (unlink-blocks call-block next-block)
689     (link-blocks call-block bind-block)
690     next-block)))
691    
692    
693 ram 1.6 ;;; Merge-Lets -- Internal
694 wlott 1.1 ;;;
695     ;;; Handle the environment semantics of let conversion. We add the lambda
696 ram 1.23 ;;; and its lets to lets for the Call's home function. We merge the calls for
697 ram 1.6 ;;; Fun with the calls for the home function, removing Fun in the process. We
698     ;;; also merge the Entries.
699 wlott 1.1 ;;;
700 ram 1.23 ;;; We also unlink the function head from the component head and set
701     ;;; Component-Reanalyze to true to indicate that the DFO should be recomputed.
702     ;;;
703 ram 1.6 (defun merge-lets (fun call)
704 wlott 1.1 (declare (type clambda fun) (type basic-combination call))
705 ram 1.23 (let ((component (block-component (node-block call))))
706     (unlink-blocks (component-head component) (node-block (lambda-bind fun)))
707     (setf (component-lambdas component)
708     (delete fun (component-lambdas component)))
709     (setf (component-reanalyze component) t))
710     (setf (lambda-call-lexenv fun) (node-lexenv call))
711     (let ((tails (lambda-tail-set fun)))
712     (setf (tail-set-functions tails)
713     (delete fun (tail-set-functions tails))))
714     (setf (lambda-tail-set fun) nil)
715     (let* ((home (node-home-lambda call))
716 ram 1.3 (home-env (lambda-environment home)))
717 wlott 1.1 (push fun (lambda-lets home))
718     (setf (lambda-home fun) home)
719 ram 1.3 (setf (lambda-environment fun) home-env)
720 wlott 1.1
721 ram 1.6 (let ((lets (lambda-lets fun)))
722 wlott 1.1 (dolist (let lets)
723 ram 1.3 (setf (lambda-home let) home)
724     (setf (lambda-environment let) home-env))
725 wlott 1.1
726     (setf (lambda-lets home) (nconc lets (lambda-lets home)))
727     (setf (lambda-lets fun) ()))
728    
729     (setf (lambda-calls home)
730     (nunion (lambda-calls fun)
731     (delete fun (lambda-calls home))))
732     (setf (lambda-calls fun) ())
733    
734     (setf (lambda-entries home)
735     (nconc (lambda-entries fun) (lambda-entries home)))
736     (setf (lambda-entries fun) ()))
737     (undefined-value))
738    
739    
740     ;;; Move-Return-Uses -- Internal
741     ;;;
742 ram 1.23 ;;; Handle the value semantics of let conversion. Delete Fun's return node,
743     ;;; and change the control flow to transfer to Next-Block instead. Move all
744     ;;; the uses of the result continuation to Call's Cont.
745 wlott 1.1 ;;;
746     ;;; If the actual continuation is only used by the let call, then we
747     ;;; intersect the type assertion on the dummy continuation with the assertion
748     ;;; for the actual continuation; in all other cases assertions on the dummy
749     ;;; continuation are lost.
750     ;;;
751 ram 1.7 ;;; We also intersect the derived type of the call with the derived type of
752     ;;; all the dummy continuation's uses. This serves mainly to propagate
753     ;;; TRULY-THE through lets.
754     ;;;
755 ram 1.23 (defun move-return-uses (fun call next-block)
756     (declare (type clambda fun) (type basic-combination call)
757     (type cblock next-block))
758     (let* ((return (lambda-return fun))
759     (return-block (node-block return)))
760     (unlink-blocks return-block
761     (component-tail (block-component return-block)))
762     (link-blocks return-block next-block)
763     (unlink-node return)
764     (delete-return return)
765     (let ((result (return-result return))
766     (cont (node-cont call))
767     (call-type (node-derived-type call)))
768     (when (eq (continuation-use cont) call)
769     (assert-continuation-type cont (continuation-asserted-type result)))
770     (unless (eq call-type *wild-type*)
771     (do-uses (use result)
772     (derive-node-type use call-type)))
773     (substitute-continuation-uses cont result)))
774     (undefined-value))
775 wlott 1.1
776    
777 ram 1.23
778     ;;; MOVE-LET-CALL-CONT -- Internal
779     ;;;
780     ;;; Change all Cont for all the calls to Fun to be the start continuation
781     ;;; for the bind node. This allows the blocks to be joined if the caller count
782     ;;; ever goes to one.
783     ;;;
784     (defun move-let-call-cont (fun)
785     (declare (type clambda fun))
786     (let ((new-cont (node-prev (lambda-bind fun))))
787     (dolist (ref (leaf-refs fun))
788     (let ((dest (continuation-dest (node-cont ref))))
789     (delete-continuation-use dest)
790     (add-continuation-use dest new-cont))))
791 wlott 1.1 (undefined-value))
792    
793    
794 ram 1.25 ;;; Unconvert-Tail-Calls -- Internal
795     ;;;
796     ;;; We are converting Fun to be a let when the call is in a non-tail
797     ;;; position. Any previously tail calls in Fun are no longer tail calls, and
798     ;;; must be restored to normal calls which transfer to Next-Block (Fun's
799 ram 1.31 ;;; return point.) We can't do this by DO-USES on the RETURN-RESULT, because
800     ;;; the return might have been deleted (if all calls were TR.)
801 ram 1.25 ;;;
802 ram 1.30 ;;; The called function might be an assignment in the case where we are
803     ;;; currently converting that function. In steady-state, assignments never
804     ;;; appear in the lambda-calls.
805     ;;;
806 ram 1.25 (defun unconvert-tail-calls (fun call next-block)
807     (dolist (called (lambda-calls fun))
808     (dolist (ref (leaf-refs called))
809     (let ((this-call (continuation-dest (node-cont ref))))
810     (when (and (node-tail-p this-call)
811     (eq (node-home-lambda this-call) fun))
812     (setf (node-tail-p this-call) nil)
813 ram 1.30 (ecase (functional-kind called)
814     ((nil :cleanup :optional)
815     (let ((block (node-block this-call)))
816     (unlink-blocks block (first (block-succ block)))
817     (link-blocks block next-block)
818     (delete-continuation-use this-call)
819     (add-continuation-use this-call (node-cont call))))
820     (:assignment
821     (assert (eq called fun))))))))
822 ram 1.25 (undefined-value))
823    
824    
825 ram 1.23 ;;; MOVE-RETURN-STUFF -- Internal
826     ;;;
827     ;;; Deal with returning from a let or assignment that we are converting.
828     ;;; FUN is the function we are calling, CALL is a call to FUN, and NEXT-BLOCK
829     ;;; is the return point for a non-tail call, or NULL if call is a tail call.
830     ;;;
831 ram 1.26 ;;; If the call is not a tail call, then we must do UNCONVERT-TAIL-CALLS, since
832     ;;; a tail call is a call which returns its value out of the enclosing non-let
833     ;;; function. When call is non-TR, we must convert it back to an ordinary
834     ;;; local call, since the value must be delivered to the receiver of CALL's
835     ;;; value.
836     ;;;
837 ram 1.23 ;;; We do different things depending on whether the caller and callee have
838     ;;; returns left:
839 ram 1.26 ;;; -- If the callee has no return we just do MOVE-LET-CALL-CONT. Either the
840     ;;; function doesn't return, or all returns are via tail-recursive local
841     ;;; calls.
842 ram 1.23 ;;; -- If CALL is a non-tail call, or if both have returns, then we
843     ;;; delete the callee's return, move its uses to the call's result
844     ;;; continuation, and transfer control to the appropriate return point.
845     ;;; -- If the callee has a return, but the caller doesn't, then we move the
846 ram 1.25 ;;; return to the caller.
847 ram 1.23 ;;;
848     (defun move-return-stuff (fun call next-block)
849     (declare (type clambda fun) (type basic-combination call)
850     (type (or cblock null) next-block))
851 ram 1.25 (when next-block
852     (unconvert-tail-calls fun call next-block))
853 ram 1.23 (let* ((return (lambda-return fun))
854     (call-fun (node-home-lambda call))
855     (call-return (lambda-return call-fun)))
856 ram 1.25 (cond ((not return))
857     ((or next-block call-return)
858     (unless (block-delete-p (node-block return))
859     (move-return-uses fun call
860     (or next-block (node-block call-return)))))
861     (t
862     (assert (node-tail-p call))
863     (setf (lambda-return call-fun) return)
864     (setf (return-lambda return) call-fun))))
865     (move-let-call-cont fun)
866 ram 1.23 (undefined-value))
867    
868    
869 wlott 1.1 ;;; Let-Convert -- Internal
870     ;;;
871     ;;; Actually do let conversion. We call subfunctions to do most of the
872     ;;; work. We change the Call's cont to be the continuation heading the bind
873     ;;; block, and also do Reoptimize-Continuation on the args and Cont so that
874 ram 1.5 ;;; let-specific IR1 optimizations get a chance. We blow away any entry for
875     ;;; the function in *free-functions* so that nobody will create new reference
876     ;;; to it.
877 wlott 1.1 ;;;
878     (defun let-convert (fun call)
879     (declare (type clambda fun) (type basic-combination call))
880 ram 1.23 (let ((next-block (if (node-tail-p call)
881     nil
882     (insert-let-body fun call))))
883 ram 1.25 (move-return-stuff fun call next-block)
884 ram 1.38 (merge-lets fun call)))
885 ram 1.23
886 ram 1.38
887     ;;; REOPTIMIZE-CALL -- Internal
888     ;;;
889     ;;; Reoptimize all of Call's args and its result.
890     ;;;
891     (defun reoptimize-call (call)
892     (declare (type basic-combination call))
893 wlott 1.1 (dolist (arg (basic-combination-args call))
894     (when arg
895     (reoptimize-continuation arg)))
896     (reoptimize-continuation (node-cont call))
897     (undefined-value))
898    
899 ram 1.38 ;;; OK-INITIAL-CONVERT-P -- Internal
900     ;;;
901     ;;; We also don't convert calls to named functions which appear in the initial
902     ;;; component, delaying this until optimization. This minimizes the likelyhood
903     ;;; that we well let-convert a function which may have references added due to
904     ;;; later local inline expansion
905     ;;;
906     (defun ok-initial-convert-p (fun)
907     (not (and (leaf-name fun)
908     (eq (component-kind
909     (block-component
910     (node-block (lambda-bind fun))))
911     :initial))))
912 wlott 1.1
913 ram 1.38
914 wlott 1.1 ;;; Maybe-Let-Convert -- Interface
915     ;;;
916     ;;; This function is called when there is some reason to believe that
917     ;;; the lambda Fun might be converted into a let. This is done after local
918     ;;; call analysis, and also when a reference is deleted. We only convert to a
919     ;;; let when the function is a normal local function, has no XEP, and is
920     ;;; referenced in exactly one local call. Conversion is also inhibited if the
921 ram 1.23 ;;; only reference is in a block about to be deleted. We return true if we
922     ;;; converted.
923 wlott 1.1 ;;;
924     ;;; These rules may seem unnecessarily restrictive, since there are some
925     ;;; cases where we could do the return with a jump that don't satisfy these
926     ;;; requirements. The reason for doing things this way is that it makes the
927 ram 1.23 ;;; concept of a let much more useful at the level of IR1 semantics. The
928     ;;; :ASSIGNMENT function kind provides another way to optimize calls to
929     ;;; single-return/multiple call functions.
930 wlott 1.1 ;;;
931     ;;; We don't attempt to convert calls to functions that have an XEP, since
932     ;;; we might be embarrassed later when we want to convert a newly discovered
933 ram 1.38 ;;; local call. Also, see OK-INITIAL-CONVERT-P.
934 wlott 1.1 ;;;
935     (defun maybe-let-convert (fun)
936     (declare (type clambda fun))
937     (let ((refs (leaf-refs fun)))
938     (when (and refs (null (rest refs))
939 ram 1.23 (member (functional-kind fun) '(nil :assignment))
940 wlott 1.1 (not (functional-entry-function fun)))
941     (let* ((ref-cont (node-cont (first refs)))
942     (dest (continuation-dest ref-cont)))
943     (when (and (basic-combination-p dest)
944     (eq (basic-combination-fun dest) ref-cont)
945 ram 1.24 (eq (basic-combination-kind dest) :local)
946 ram 1.36 (not (block-delete-p (node-block dest)))
947 ram 1.38 (cond ((ok-initial-convert-p fun) t)
948     (t
949 ram 1.36 (reoptimize-continuation ref-cont)
950 ram 1.38 nil)))
951     (unless (eq (functional-kind fun) :assignment)
952     (let-convert fun dest))
953     (reoptimize-call dest)
954 wlott 1.1 (setf (functional-kind fun)
955 ram 1.23 (if (mv-combination-p dest) :mv-let :let))))
956     t)))
957    
958    
959     ;;;; Tail local calls and assignments:
960    
961     ;;; ONLY-HARMLESS-CLEANUPS -- Internal
962     ;;;
963     ;;; Return T if there are no cleanups between Block1 and Block2, or if they
964     ;;; definitely won't generate any cleanup code. Currently we recognize lexical
965     ;;; entry points that are only used locally (if at all).
966     ;;;
967     (defun only-harmless-cleanups (block1 block2)
968     (declare (type cblock block1 block2))
969     (or (eq block1 block2)
970     (let ((cleanup2 (block-start-cleanup block2)))
971     (do ((cleanup (block-end-cleanup block1)
972     (node-enclosing-cleanup (cleanup-mess-up cleanup))))
973     ((eq cleanup cleanup2) t)
974     (case (cleanup-kind cleanup)
975     ((:block :tagbody)
976     (unless (null (entry-exits (cleanup-mess-up cleanup)))
977     (return nil)))
978     (t (return nil)))))))
979    
980    
981     ;;; MAYBE-CONVERT-TAIL-LOCAL-CALL -- Interface
982     ;;;
983 ram 1.31 ;;; If a potentially TR local call really is TR, then convert it to jump
984     ;;; directly to the called function. We also call MAYBE-CONVERT-TO-ASSIGNMENT.
985     ;;; We can switch the succesor (potentially deleting the RETURN node) unless:
986     ;;; -- The call has already been converted.
987     ;;; -- The call isn't TR (random implicit MV PROG1.)
988 ram 1.23 ;;; -- The call is in an XEP (thus we might decide to make it non-tail so that
989     ;;; we can use known return inside the component.)
990     ;;; -- There is a change in the cleanup between the call in the return, so we
991     ;;; might need to introduce cleanup code.
992     ;;;
993     (defun maybe-convert-tail-local-call (call)
994     (declare (type combination call))
995     (let ((return (continuation-dest (node-cont call))))
996     (assert (return-p return))
997     (when (and (not (node-tail-p call))
998 ram 1.31 (immediately-used-p (return-result return) call)
999 ram 1.23 (not (eq (functional-kind (node-home-lambda call))
1000     :external))
1001     (only-harmless-cleanups (node-block call)
1002     (node-block return)))
1003     (node-ends-block call)
1004     (let ((block (node-block call))
1005     (fun (combination-lambda call)))
1006     (setf (node-tail-p call) t)
1007     (unlink-blocks block (first (block-succ block)))
1008     (link-blocks block (node-block (lambda-bind fun)))
1009     (values t (maybe-convert-to-assignment fun))))))
1010    
1011    
1012     ;;; MAYBE-CONVERT-TO-ASSIGNMENT -- Interface
1013     ;;;
1014     ;;; Called when we believe it might make sense to convert Fun to an
1015 ram 1.25 ;;; assignment. All this function really does is determine when a function
1016     ;;; with more than one call can still be combined with the calling function's
1017     ;;; environment. We can convert when:
1018 ram 1.23 ;;; -- The function is a normal, non-entry function, and
1019 ram 1.25 ;;; -- Except for one call, all calls must be tail recursive calls in the
1020     ;;; called function (i.e. are self-recursive tail calls)
1021 ram 1.38 ;;; -- OK-INITIAL-CONVERT-P is true.
1022 ram 1.23 ;;;
1023 ram 1.25 ;;; There may be one outside call, and it need not be tail-recursive. Since
1024     ;;; all tail local calls have already been converted to direct transfers, the
1025     ;;; only control semantics needed are to splice in the body at the non-tail
1026     ;;; call. If there is no non-tail call, then we need only merge the
1027     ;;; environments. Both cases are handled by LET-CONVERT.
1028     ;;;
1029     ;;; ### It would actually be possible to allow any number of outside calls as
1030     ;;; long as they all return to the same place (i.e. have the same conceptual
1031     ;;; continuation.) A special case of this would be when all of the outside
1032     ;;; calls are tail recursive.
1033 ram 1.23 ;;;
1034     (defun maybe-convert-to-assignment (fun)
1035     (declare (type clambda fun))
1036     (when (and (not (functional-kind fun))
1037     (not (functional-entry-function fun)))
1038     (let ((non-tail nil)
1039     (call-fun nil))
1040 ram 1.38 (when (and (dolist (ref (leaf-refs fun) t)
1041     (let ((dest (continuation-dest (node-cont ref))))
1042     (when (block-delete-p (node-block dest)) (return nil))
1043     (let ((home (node-home-lambda ref)))
1044     (unless (eq home fun)
1045     (when call-fun (return nil))
1046     (setq call-fun home))
1047     (unless (node-tail-p dest)
1048     (when (or non-tail (eq home fun)) (return nil))
1049     (setq non-tail dest)))))
1050     (ok-initial-convert-p fun))
1051 ram 1.30 (setf (functional-kind fun) :assignment)
1052 ram 1.23 (let-convert fun (or non-tail
1053     (continuation-dest
1054     (node-cont (first (leaf-refs fun))))))
1055 ram 1.38 (when non-tail (reoptimize-call non-tail))
1056 ram 1.23 t))))

  ViewVC Help
Powered by ViewVC 1.1.5