xref: /freebsd/usr.bin/gprof/arcs.c (revision 6137b5f7b8c183ee8806d79b3f1d8e5e3ddb3df3)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #include <err.h>
34 #include "gprof.h"
35 
36 #ifdef DEBUG
37 int visited;
38 int viable;
39 int newcycle;
40 int oldcycle;
41 #endif /* DEBUG */
42 
43 int topcmp(const void *, const void *);
44 
45     /*
46      *	add (or just increment) an arc
47      */
48 void
49 addarc(nltype *parentp, nltype *childp, long count)
50 {
51     arctype		*arcp;
52 
53 #   ifdef DEBUG
54 	if ( debug & TALLYDEBUG ) {
55 	    printf( "[addarc] %ld arcs from %s to %s\n" ,
56 		    count , parentp -> name , childp -> name );
57 	}
58 #   endif /* DEBUG */
59     arcp = arclookup( parentp , childp );
60     if ( arcp != 0 ) {
61 	    /*
62 	     *	a hit:  just increment the count.
63 	     */
64 #	ifdef DEBUG
65 	    if ( debug & TALLYDEBUG ) {
66 		printf( "[tally] hit %ld += %ld\n" ,
67 			arcp -> arc_count , count );
68 	    }
69 #	endif /* DEBUG */
70 	arcp -> arc_count += count;
71 	return;
72     }
73     arcp = (arctype *)calloc( 1 , sizeof *arcp );
74     if (arcp == NULL)
75 	errx( 1 , "malloc failed" );
76     arcp -> arc_parentp = parentp;
77     arcp -> arc_childp = childp;
78     arcp -> arc_count = count;
79 	/*
80 	 *	prepend this child to the children of this parent
81 	 */
82     arcp -> arc_childlist = parentp -> children;
83     parentp -> children = arcp;
84 	/*
85 	 *	prepend this parent to the parents of this child
86 	 */
87     arcp -> arc_parentlist = childp -> parents;
88     childp -> parents = arcp;
89 }
90 
91     /*
92      *	the code below topologically sorts the graph (collapsing cycles),
93      *	and propagates time bottom up and flags top down.
94      */
95 
96     /*
97      *	the topologically sorted name list pointers
98      */
99 nltype	**topsortnlp;
100 
101 int
102 topcmp(const void *v1, const void *v2)
103 {
104     const nltype **npp1 = (const nltype **)v1;
105     const nltype **npp2 = (const nltype **)v2;
106 
107     return (*npp1) -> toporder - (*npp2) -> toporder;
108 }
109 
110 nltype **
111 doarcs(void)
112 {
113     nltype	*parentp, **timesortnlp;
114     arctype	*arcp;
115     long	index;
116     long	pass;
117 
118 	/*
119 	 *	initialize various things:
120 	 *	    zero out child times.
121 	 *	    count self-recursive calls.
122 	 *	    indicate that nothing is on cycles.
123 	 */
124     for ( parentp = nl ; parentp < npe ; parentp++ ) {
125 	parentp -> childtime = 0.0;
126 	arcp = arclookup( parentp , parentp );
127 	if ( arcp != 0 ) {
128 	    parentp -> ncall -= arcp -> arc_count;
129 	    parentp -> selfcalls = arcp -> arc_count;
130 	} else {
131 	    parentp -> selfcalls = 0;
132 	}
133 	parentp -> npropcall = parentp -> ncall;
134 	parentp -> propfraction = 0.0;
135 	parentp -> propself = 0.0;
136 	parentp -> propchild = 0.0;
137 	parentp -> printflag = FALSE;
138 	parentp -> toporder = DFN_NAN;
139 	parentp -> cycleno = 0;
140 	parentp -> cyclehead = parentp;
141 	parentp -> cnext = 0;
142     }
143     for ( pass = 1 ; ; pass++ ) {
144 	    /*
145 	     *	topologically order things
146 	     *	if any node is unnumbered,
147 	     *	    number it and any of its descendents.
148 	     */
149 	for ( dfn_init() , parentp = nl ; parentp < npe ; parentp++ ) {
150 	    if ( parentp -> toporder == DFN_NAN ) {
151 		dfn( parentp );
152 	    }
153 	}
154 	    /*
155 	     *	link together nodes on the same cycle
156 	     */
157 	cyclelink();
158 	    /*
159 	     *	if no cycles to break up, proceed
160 	     */
161 	if ( ! Cflag )
162 	    break;
163 	    /*
164 	     *	analyze cycles to determine breakup
165 	     */
166 #	ifdef DEBUG
167 	    if ( debug & BREAKCYCLE ) {
168 		printf("[doarcs] pass %ld, cycle(s) %d\n" , pass , ncycle );
169 	    }
170 #	endif /* DEBUG */
171 	if ( pass == 1 ) {
172 	    printf( "\n\n%s %s\n%s %d:\n" ,
173 		"The following arcs were deleted" ,
174 		"from the propagation calculation" ,
175 		"to reduce the maximum cycle size to", cyclethreshold );
176 	}
177 	if ( cycleanalyze() )
178 	    break;
179 	free ( cyclenl );
180 	ncycle = 0;
181 	for ( parentp = nl ; parentp < npe ; parentp++ ) {
182 	    parentp -> toporder = DFN_NAN;
183 	    parentp -> cycleno = 0;
184 	    parentp -> cyclehead = parentp;
185 	    parentp -> cnext = 0;
186 	}
187     }
188     if ( pass > 1 ) {
189 	printf( "\f\n" );
190     } else {
191 	printf( "\tNone\n\n" );
192     }
193 	/*
194 	 *	Sort the symbol table in reverse topological order
195 	 */
196     topsortnlp = (nltype **) calloc( nname , sizeof(nltype *) );
197     if ( topsortnlp == (nltype **) 0 )
198 	errx( 1 , "[doarcs] ran out of memory for topo sorting" );
199     for ( index = 0 ; index < nname ; index += 1 ) {
200 	topsortnlp[ index ] = &nl[ index ];
201     }
202     qsort( topsortnlp , nname , sizeof(nltype *) , topcmp );
203 #   ifdef DEBUG
204 	if ( debug & DFNDEBUG ) {
205 	    printf( "[doarcs] topological sort listing\n" );
206 	    for ( index = 0 ; index < nname ; index += 1 ) {
207 		printf( "[doarcs] " );
208 		printf( "%d:" , topsortnlp[ index ] -> toporder );
209 		printname( topsortnlp[ index ] );
210 		printf( "\n" );
211 	    }
212 	}
213 #   endif /* DEBUG */
214 	/*
215 	 *	starting from the topological top,
216 	 *	propagate print flags to children.
217 	 *	also, calculate propagation fractions.
218 	 *	this happens before time propagation
219 	 *	since time propagation uses the fractions.
220 	 */
221     doflags();
222 	/*
223 	 *	starting from the topological bottom,
224 	 *	propagate children times up to parents.
225 	 */
226     dotime();
227 	/*
228 	 *	Now, sort by propself + propchild.
229 	 *	sorting both the regular function names
230 	 *	and cycle headers.
231 	 */
232     timesortnlp = (nltype **) calloc( nname + ncycle , sizeof(nltype *) );
233     if ( timesortnlp == (nltype **) 0 )
234 	errx( 1 , "ran out of memory for sorting" );
235     for ( index = 0 ; index < nname ; index++ ) {
236 	timesortnlp[index] = &nl[index];
237     }
238     for ( index = 1 ; index <= ncycle ; index++ ) {
239 	timesortnlp[nname+index-1] = &cyclenl[index];
240     }
241     qsort( timesortnlp , nname + ncycle , sizeof(nltype *) , totalcmp );
242     for ( index = 0 ; index < nname + ncycle ; index++ ) {
243 	timesortnlp[ index ] -> index = index + 1;
244     }
245     return( timesortnlp );
246 }
247 
248 void
249 dotime(void)
250 {
251     int	index;
252 
253     cycletime();
254     for ( index = 0 ; index < nname ; index += 1 ) {
255 	timepropagate( topsortnlp[ index ] );
256     }
257 }
258 
259 void
260 timepropagate(nltype *parentp)
261 {
262     arctype	*arcp;
263     nltype	*childp;
264     double	share;
265     double	propshare;
266 
267     if ( parentp -> propfraction == 0.0 ) {
268 	return;
269     }
270 	/*
271 	 *	gather time from children of this parent.
272 	 */
273     for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
274 	childp = arcp -> arc_childp;
275 	if ( arcp -> arc_flags & DEADARC ) {
276 	    continue;
277 	}
278 	if ( arcp -> arc_count == 0 ) {
279 	    continue;
280 	}
281 	if ( childp == parentp ) {
282 	    continue;
283 	}
284 	if ( childp -> propfraction == 0.0 ) {
285 	    continue;
286 	}
287 	if ( childp -> cyclehead != childp ) {
288 	    if ( parentp -> cycleno == childp -> cycleno ) {
289 		continue;
290 	    }
291 	    if ( parentp -> toporder <= childp -> toporder ) {
292 		fprintf( stderr , "[propagate] toporder botches\n" );
293 	    }
294 	    childp = childp -> cyclehead;
295 	} else {
296 	    if ( parentp -> toporder <= childp -> toporder ) {
297 		fprintf( stderr , "[propagate] toporder botches\n" );
298 		continue;
299 	    }
300 	}
301 	if ( childp -> npropcall == 0 ) {
302 	    continue;
303 	}
304 	    /*
305 	     *	distribute time for this arc
306 	     */
307 	arcp -> arc_time = childp -> time
308 			        * ( ( (double) arcp -> arc_count ) /
309 				    ( (double) childp -> npropcall ) );
310 	arcp -> arc_childtime = childp -> childtime
311 			        * ( ( (double) arcp -> arc_count ) /
312 				    ( (double) childp -> npropcall ) );
313 	share = arcp -> arc_time + arcp -> arc_childtime;
314 	parentp -> childtime += share;
315 	    /*
316 	     *	( 1 - propfraction ) gets lost along the way
317 	     */
318 	propshare = parentp -> propfraction * share;
319 	    /*
320 	     *	fix things for printing
321 	     */
322 	parentp -> propchild += propshare;
323 	arcp -> arc_time *= parentp -> propfraction;
324 	arcp -> arc_childtime *= parentp -> propfraction;
325 	    /*
326 	     *	add this share to the parent's cycle header, if any.
327 	     */
328 	if ( parentp -> cyclehead != parentp ) {
329 	    parentp -> cyclehead -> childtime += share;
330 	    parentp -> cyclehead -> propchild += propshare;
331 	}
332 #	ifdef DEBUG
333 	    if ( debug & PROPDEBUG ) {
334 		printf( "[dotime] child \t" );
335 		printname( childp );
336 		printf( " with %f %f %ld/%ld\n" ,
337 			childp -> time , childp -> childtime ,
338 			arcp -> arc_count , childp -> npropcall );
339 		printf( "[dotime] parent\t" );
340 		printname( parentp );
341 		printf( "\n[dotime] share %f\n" , share );
342 	    }
343 #	endif /* DEBUG */
344     }
345 }
346 
347 void
348 cyclelink(void)
349 {
350     register nltype	*nlp;
351     register nltype	*cyclenlp;
352     int			cycle;
353     nltype		*memberp;
354     arctype		*arcp;
355 
356 	/*
357 	 *	Count the number of cycles, and initialize the cycle lists
358 	 */
359     ncycle = 0;
360     for ( nlp = nl ; nlp < npe ; nlp++ ) {
361 	    /*
362 	     *	this is how you find unattached cycles
363 	     */
364 	if ( nlp -> cyclehead == nlp && nlp -> cnext != 0 ) {
365 	    ncycle += 1;
366 	}
367     }
368 	/*
369 	 *	cyclenl is indexed by cycle number:
370 	 *	i.e. it is origin 1, not origin 0.
371 	 */
372     cyclenl = (nltype *) calloc( ncycle + 1 , sizeof( nltype ) );
373     if ( cyclenl == NULL )
374 	errx( 1 , "no room for %zu bytes of cycle headers" ,
375 		   ( ncycle + 1 ) * sizeof( nltype ) );
376 	/*
377 	 *	now link cycles to true cycleheads,
378 	 *	number them, accumulate the data for the cycle
379 	 */
380     cycle = 0;
381     for ( nlp = nl ; nlp < npe ; nlp++ ) {
382 	if ( !( nlp -> cyclehead == nlp && nlp -> cnext != 0 ) ) {
383 	    continue;
384 	}
385 	cycle += 1;
386 	cyclenlp = &cyclenl[cycle];
387         cyclenlp -> name = 0;		/* the name */
388         cyclenlp -> value = 0;		/* the pc entry point */
389         cyclenlp -> time = 0.0;		/* ticks in this routine */
390         cyclenlp -> childtime = 0.0;	/* cumulative ticks in children */
391 	cyclenlp -> ncall = 0;		/* how many times called */
392 	cyclenlp -> selfcalls = 0;	/* how many calls to self */
393 	cyclenlp -> propfraction = 0.0;	/* what % of time propagates */
394 	cyclenlp -> propself = 0.0;	/* how much self time propagates */
395 	cyclenlp -> propchild = 0.0;	/* how much child time propagates */
396 	cyclenlp -> printflag = TRUE;	/* should this be printed? */
397 	cyclenlp -> index = 0;		/* index in the graph list */
398 	cyclenlp -> toporder = DFN_NAN;	/* graph call chain top-sort order */
399 	cyclenlp -> cycleno = cycle;	/* internal number of cycle on */
400 	cyclenlp -> cyclehead = cyclenlp;	/* pointer to head of cycle */
401 	cyclenlp -> cnext = nlp;	/* pointer to next member of cycle */
402 	cyclenlp -> parents = 0;	/* list of caller arcs */
403 	cyclenlp -> children = 0;	/* list of callee arcs */
404 #	ifdef DEBUG
405 	    if ( debug & CYCLEDEBUG ) {
406 		printf( "[cyclelink] " );
407 		printname( nlp );
408 		printf( " is the head of cycle %d\n" , cycle );
409 	    }
410 #	endif /* DEBUG */
411 	    /*
412 	     *	link members to cycle header
413 	     */
414 	for ( memberp = nlp ; memberp ; memberp = memberp -> cnext ) {
415 	    memberp -> cycleno = cycle;
416 	    memberp -> cyclehead = cyclenlp;
417 	}
418 	    /*
419 	     *	count calls from outside the cycle
420 	     *	and those among cycle members
421 	     */
422 	for ( memberp = nlp ; memberp ; memberp = memberp -> cnext ) {
423 	    for ( arcp=memberp->parents ; arcp ; arcp=arcp->arc_parentlist ) {
424 		if ( arcp -> arc_parentp == memberp ) {
425 		    continue;
426 		}
427 		if ( arcp -> arc_parentp -> cycleno == cycle ) {
428 		    cyclenlp -> selfcalls += arcp -> arc_count;
429 		} else {
430 		    cyclenlp -> npropcall += arcp -> arc_count;
431 		}
432 	    }
433 	}
434     }
435 }
436 
437     /*
438      *	analyze cycles to determine breakup
439      */
440 bool
441 cycleanalyze(void)
442 {
443     arctype	**cyclestack;
444     arctype	**stkp;
445     arctype	**arcpp;
446     arctype	**endlist;
447     arctype	*arcp;
448     nltype	*nlp;
449     cltype	*clp;
450     bool	ret;
451     bool	done;
452     int		size;
453     int		cycleno;
454 
455 	/*
456 	 *	calculate the size of the cycle, and find nodes that
457 	 *	exit the cycle as they are desirable targets to cut
458 	 *	some of their parents
459 	 */
460     for ( done = TRUE , cycleno = 1 ; cycleno <= ncycle ; cycleno++ ) {
461 	size = 0;
462 	for (nlp = cyclenl[ cycleno ] . cnext; nlp; nlp = nlp -> cnext) {
463 	    size += 1;
464 	    nlp -> parentcnt = 0;
465 	    nlp -> flags &= ~HASCYCLEXIT;
466 	    for ( arcp = nlp -> parents; arcp; arcp = arcp -> arc_parentlist ) {
467 		nlp -> parentcnt += 1;
468 		if ( arcp -> arc_parentp -> cycleno != cycleno )
469 		    nlp -> flags |= HASCYCLEXIT;
470 	    }
471 	}
472 	if ( size <= cyclethreshold )
473 	    continue;
474 	done = FALSE;
475         cyclestack = (arctype **) calloc( size + 1 , sizeof( arctype *) );
476 	if ( cyclestack == NULL )
477 	    errx( 1, "no room for %zu bytes of cycle stack" ,
478 			   ( size + 1 ) * sizeof( arctype * ) );
479 #	ifdef DEBUG
480 	    if ( debug & BREAKCYCLE ) {
481 		printf( "[cycleanalyze] starting cycle %d of %d, size %d\n" ,
482 		    cycleno , ncycle , size );
483 	    }
484 #	endif /* DEBUG */
485 	for ( nlp = cyclenl[ cycleno ] . cnext ; nlp ; nlp = nlp -> cnext ) {
486 	    stkp = &cyclestack[0];
487 	    nlp -> flags |= CYCLEHEAD;
488 	    ret = descend ( nlp , cyclestack , stkp );
489 	    nlp -> flags &= ~CYCLEHEAD;
490 	    if ( ret == FALSE )
491 		break;
492 	}
493 	free( cyclestack );
494 	if ( cyclecnt > 0 ) {
495 	    compresslist();
496 	    for ( clp = cyclehead ; clp ; ) {
497 		endlist = &clp -> list[ clp -> size ];
498 		for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
499 		    (*arcpp) -> arc_cyclecnt--;
500 		cyclecnt--;
501 		clp = clp -> next;
502 		free( clp );
503 	    }
504 	    cyclehead = 0;
505 	}
506     }
507 #   ifdef DEBUG
508 	if ( debug & BREAKCYCLE ) {
509 	    printf("%s visited %d, viable %d, newcycle %d, oldcycle %d\n",
510 		"[doarcs]" , visited , viable , newcycle , oldcycle);
511 	}
512 #   endif /* DEBUG */
513     return( done );
514 }
515 
516 bool
517 descend(nltype *node, arctype **stkstart, arctype **stkp)
518 {
519     arctype	*arcp;
520     bool	ret;
521 
522     for ( arcp = node -> children ; arcp ; arcp = arcp -> arc_childlist ) {
523 #	ifdef DEBUG
524 	    visited++;
525 #	endif /* DEBUG */
526 	if ( arcp -> arc_childp -> cycleno != node -> cycleno
527 	    || ( arcp -> arc_childp -> flags & VISITED )
528 	    || ( arcp -> arc_flags & DEADARC ) )
529 	    continue;
530 #	ifdef DEBUG
531 	    viable++;
532 #	endif /* DEBUG */
533 	*stkp = arcp;
534 	if ( arcp -> arc_childp -> flags & CYCLEHEAD ) {
535 	    if ( addcycle( stkstart , stkp ) == FALSE )
536 		return( FALSE );
537 	    continue;
538 	}
539 	arcp -> arc_childp -> flags |= VISITED;
540 	ret = descend( arcp -> arc_childp , stkstart , stkp + 1 );
541 	arcp -> arc_childp -> flags &= ~VISITED;
542 	if ( ret == FALSE )
543 	    return( FALSE );
544     }
545     return( TRUE );
546 }
547 
548 bool
549 addcycle(arctype **stkstart, arctype **stkend)
550 {
551     arctype	**arcpp;
552     arctype	**stkloc;
553     arctype	**stkp;
554     arctype	**endlist;
555     arctype	*minarc;
556     arctype	*arcp;
557     cltype	*clp;
558     int		size;
559 
560     size = stkend - stkstart + 1;
561     if ( size <= 1 )
562 	return( TRUE );
563     for ( arcpp = stkstart , minarc = *arcpp ; arcpp <= stkend ; arcpp++ ) {
564 	if ( *arcpp > minarc )
565 	    continue;
566 	minarc = *arcpp;
567 	stkloc = arcpp;
568     }
569     for ( clp = cyclehead ; clp ; clp = clp -> next ) {
570 	if ( clp -> size != size )
571 	    continue;
572 	stkp = stkloc;
573 	endlist = &clp -> list[ size ];
574 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ ) {
575 	    if ( *stkp++ != *arcpp )
576 		break;
577 	    if ( stkp > stkend )
578 		stkp = stkstart;
579 	}
580 	if ( arcpp == endlist ) {
581 #	    ifdef DEBUG
582 		oldcycle++;
583 #	    endif /* DEBUG */
584 	    return( TRUE );
585 	}
586     }
587     clp = (cltype *)
588 	calloc( 1 , sizeof ( cltype ) + ( size - 1 ) * sizeof( arctype * ) );
589     if ( clp == NULL ) {
590 	warnx( "no room for %zu bytes of subcycle storage" ,
591 	    sizeof ( cltype ) + ( size - 1 ) * sizeof( arctype * ) );
592 	return( FALSE );
593     }
594     stkp = stkloc;
595     endlist = &clp -> list[ size ];
596     for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ ) {
597 	arcp = *arcpp = *stkp++;
598 	if ( stkp > stkend )
599 	    stkp = stkstart;
600 	arcp -> arc_cyclecnt++;
601 	if ( ( arcp -> arc_flags & ONLIST ) == 0 ) {
602 	    arcp -> arc_flags |= ONLIST;
603 	    arcp -> arc_next = archead;
604 	    archead = arcp;
605 	}
606     }
607     clp -> size = size;
608     clp -> next = cyclehead;
609     cyclehead = clp;
610 #   ifdef DEBUG
611 	newcycle++;
612 	if ( debug & SUBCYCLELIST ) {
613 	    printsubcycle( clp );
614 	}
615 #   endif /* DEBUG */
616     cyclecnt++;
617     if ( cyclecnt >= CYCLEMAX )
618 	return( FALSE );
619     return( TRUE );
620 }
621 
622 void
623 compresslist(void)
624 {
625     cltype	*clp;
626     cltype	**prev;
627     arctype	**arcpp;
628     arctype	**endlist;
629     arctype	*arcp;
630     arctype	*maxarcp;
631     arctype	*maxexitarcp;
632     arctype	*maxwithparentarcp;
633     arctype	*maxnoparentarcp;
634     int		maxexitcnt;
635     int		maxwithparentcnt;
636     int		maxnoparentcnt;
637 #   ifdef DEBUG
638 	const char	*type;
639 #   endif /* DEBUG */
640 
641     maxexitcnt = 0;
642     maxwithparentcnt = 0;
643     maxnoparentcnt = 0;
644     for ( endlist = &archead , arcp = archead ; arcp ; ) {
645 	if ( arcp -> arc_cyclecnt == 0 ) {
646 	    arcp -> arc_flags &= ~ONLIST;
647 	    *endlist = arcp -> arc_next;
648 	    arcp -> arc_next = 0;
649 	    arcp = *endlist;
650 	    continue;
651 	}
652 	if ( arcp -> arc_childp -> flags & HASCYCLEXIT ) {
653 	    if ( arcp -> arc_cyclecnt > maxexitcnt ||
654 		( arcp -> arc_cyclecnt == maxexitcnt &&
655 		arcp -> arc_cyclecnt < maxexitarcp -> arc_count ) ) {
656 		maxexitcnt = arcp -> arc_cyclecnt;
657 		maxexitarcp = arcp;
658 	    }
659 	} else if ( arcp -> arc_childp -> parentcnt > 1 ) {
660 	    if ( arcp -> arc_cyclecnt > maxwithparentcnt ||
661 		( arcp -> arc_cyclecnt == maxwithparentcnt &&
662 		arcp -> arc_cyclecnt < maxwithparentarcp -> arc_count ) ) {
663 		maxwithparentcnt = arcp -> arc_cyclecnt;
664 		maxwithparentarcp = arcp;
665 	    }
666 	} else {
667 	    if ( arcp -> arc_cyclecnt > maxnoparentcnt ||
668 		( arcp -> arc_cyclecnt == maxnoparentcnt &&
669 		arcp -> arc_cyclecnt < maxnoparentarcp -> arc_count ) ) {
670 		maxnoparentcnt = arcp -> arc_cyclecnt;
671 		maxnoparentarcp = arcp;
672 	    }
673 	}
674 	endlist = &arcp -> arc_next;
675 	arcp = arcp -> arc_next;
676     }
677     if ( maxexitcnt > 0 ) {
678 	/*
679 	 *	first choice is edge leading to node with out-of-cycle parent
680 	 */
681 	maxarcp = maxexitarcp;
682 #	ifdef DEBUG
683 	    type = "exit";
684 #	endif /* DEBUG */
685     } else if ( maxwithparentcnt > 0 ) {
686 	/*
687 	 *	second choice is edge leading to node with at least one
688 	 *	other in-cycle parent
689 	 */
690 	maxarcp = maxwithparentarcp;
691 #	ifdef DEBUG
692 	    type = "internal";
693 #	endif /* DEBUG */
694     } else {
695 	/*
696 	 *	last choice is edge leading to node with only this arc as
697 	 *	a parent (as it will now be orphaned)
698 	 */
699 	maxarcp = maxnoparentarcp;
700 #	ifdef DEBUG
701 	    type = "orphan";
702 #	endif /* DEBUG */
703     }
704     maxarcp -> arc_flags |= DEADARC;
705     maxarcp -> arc_childp -> parentcnt -= 1;
706     maxarcp -> arc_childp -> npropcall -= maxarcp -> arc_count;
707 #   ifdef DEBUG
708 	if ( debug & BREAKCYCLE ) {
709 	    printf( "%s delete %s arc: %s (%ld) -> %s from %u cycle(s)\n" ,
710 		"[compresslist]" , type , maxarcp -> arc_parentp -> name ,
711 		maxarcp -> arc_count , maxarcp -> arc_childp -> name ,
712 		maxarcp -> arc_cyclecnt );
713 	}
714 #   endif /* DEBUG */
715     printf( "\t%s to %s with %ld calls\n" , maxarcp -> arc_parentp -> name ,
716 	maxarcp -> arc_childp -> name , maxarcp -> arc_count );
717     prev = &cyclehead;
718     for ( clp = cyclehead ; clp ; ) {
719 	endlist = &clp -> list[ clp -> size ];
720 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
721 	    if ( (*arcpp) -> arc_flags & DEADARC )
722 		break;
723 	if ( arcpp == endlist ) {
724 	    prev = &clp -> next;
725 	    clp = clp -> next;
726 	    continue;
727 	}
728 	for ( arcpp = clp -> list ; arcpp < endlist ; arcpp++ )
729 	    (*arcpp) -> arc_cyclecnt--;
730 	cyclecnt--;
731 	*prev = clp -> next;
732 	clp = clp -> next;
733 	free( clp );
734     }
735 }
736 
737 #ifdef DEBUG
738 void
739 printsubcycle(cltype *clp)
740 {
741     arctype	**arcpp;
742     arctype	**endlist;
743 
744     arcpp = clp -> list;
745     printf( "%s <cycle %d>\n" , (*arcpp) -> arc_parentp -> name ,
746 	(*arcpp) -> arc_parentp -> cycleno ) ;
747     for ( endlist = &clp -> list[ clp -> size ]; arcpp < endlist ; arcpp++ )
748 	printf( "\t(%ld) -> %s\n" , (*arcpp) -> arc_count ,
749 	    (*arcpp) -> arc_childp -> name ) ;
750 }
751 #endif /* DEBUG */
752 
753 void
754 cycletime(void)
755 {
756     int			cycle;
757     nltype		*cyclenlp;
758     nltype		*childp;
759 
760     for ( cycle = 1 ; cycle <= ncycle ; cycle += 1 ) {
761 	cyclenlp = &cyclenl[ cycle ];
762 	for ( childp = cyclenlp -> cnext ; childp ; childp = childp -> cnext ) {
763 	    if ( childp -> propfraction == 0.0 ) {
764 		    /*
765 		     * all members have the same propfraction except those
766 		     *	that were excluded with -E
767 		     */
768 		continue;
769 	    }
770 	    cyclenlp -> time += childp -> time;
771 	}
772 	cyclenlp -> propself = cyclenlp -> propfraction * cyclenlp -> time;
773     }
774 }
775 
776     /*
777      *	in one top to bottom pass over the topologically sorted namelist
778      *	propagate:
779      *		printflag as the union of parents' printflags
780      *		propfraction as the sum of fractional parents' propfractions
781      *	and while we're here, sum time for functions.
782      */
783 void
784 doflags(void)
785 {
786     int		index;
787     nltype	*childp;
788     nltype	*oldhead;
789 
790     oldhead = 0;
791     for ( index = nname-1 ; index >= 0 ; index -= 1 ) {
792 	childp = topsortnlp[ index ];
793 	    /*
794 	     *	if we haven't done this function or cycle,
795 	     *	inherit things from parent.
796 	     *	this way, we are linear in the number of arcs
797 	     *	since we do all members of a cycle (and the cycle itself)
798 	     *	as we hit the first member of the cycle.
799 	     */
800 	if ( childp -> cyclehead != oldhead ) {
801 	    oldhead = childp -> cyclehead;
802 	    inheritflags( childp );
803 	}
804 #	ifdef DEBUG
805 	    if ( debug & PROPDEBUG ) {
806 		printf( "[doflags] " );
807 		printname( childp );
808 		printf( " inherits printflag %d and propfraction %f\n" ,
809 			childp -> printflag , childp -> propfraction );
810 	    }
811 #	endif /* DEBUG */
812 	if ( ! childp -> printflag ) {
813 		/*
814 		 *	printflag is off
815 		 *	it gets turned on by
816 		 *	being on -f list,
817 		 *	or there not being any -f list and not being on -e list.
818 		 */
819 	    if (   onlist( flist , childp -> name )
820 		|| ( !fflag && !onlist( elist , childp -> name ) ) ) {
821 		childp -> printflag = TRUE;
822 	    }
823 	} else {
824 		/*
825 		 *	this function has printing parents:
826 		 *	maybe someone wants to shut it up
827 		 *	by putting it on -e list.  (but favor -f over -e)
828 		 */
829 	    if (  ( !onlist( flist , childp -> name ) )
830 		&& onlist( elist , childp -> name ) ) {
831 		childp -> printflag = FALSE;
832 	    }
833 	}
834 	if ( childp -> propfraction == 0.0 ) {
835 		/*
836 		 *	no parents to pass time to.
837 		 *	collect time from children if
838 		 *	its on -F list,
839 		 *	or there isn't any -F list and its not on -E list.
840 		 */
841 	    if ( onlist( Flist , childp -> name )
842 		|| ( !Fflag && !onlist( Elist , childp -> name ) ) ) {
843 		    childp -> propfraction = 1.0;
844 	    }
845 	} else {
846 		/*
847 		 *	it has parents to pass time to,
848 		 *	but maybe someone wants to shut it up
849 		 *	by putting it on -E list.  (but favor -F over -E)
850 		 */
851 	    if (  !onlist( Flist , childp -> name )
852 		&& onlist( Elist , childp -> name ) ) {
853 		childp -> propfraction = 0.0;
854 	    }
855 	}
856 	childp -> propself = childp -> time * childp -> propfraction;
857 	printtime += childp -> propself;
858 #	ifdef DEBUG
859 	    if ( debug & PROPDEBUG ) {
860 		printf( "[doflags] " );
861 		printname( childp );
862 		printf( " ends up with printflag %d and propfraction %f\n" ,
863 			childp -> printflag , childp -> propfraction );
864 		printf( "time %f propself %f printtime %f\n" ,
865 			childp -> time , childp -> propself , printtime );
866 	    }
867 #	endif /* DEBUG */
868     }
869 }
870 
871     /*
872      *	check if any parent of this child
873      *	(or outside parents of this cycle)
874      *	have their print flags on and set the
875      *	print flag of the child (cycle) appropriately.
876      *	similarly, deal with propagation fractions from parents.
877      */
878 void
879 inheritflags(nltype *childp)
880 {
881     nltype	*headp;
882     arctype	*arcp;
883     nltype	*parentp;
884     nltype	*memp;
885 
886     headp = childp -> cyclehead;
887     if ( childp == headp ) {
888 	    /*
889 	     *	just a regular child, check its parents
890 	     */
891 	childp -> printflag = FALSE;
892 	childp -> propfraction = 0.0;
893 	for (arcp = childp -> parents ; arcp ; arcp = arcp -> arc_parentlist) {
894 	    parentp = arcp -> arc_parentp;
895 	    if ( childp == parentp ) {
896 		continue;
897 	    }
898 	    childp -> printflag |= parentp -> printflag;
899 		/*
900 		 *	if the child was never actually called
901 		 *	(e.g. this arc is static (and all others are, too))
902 		 *	no time propagates along this arc.
903 		 */
904 	    if ( arcp -> arc_flags & DEADARC ) {
905 		continue;
906 	    }
907 	    if ( childp -> npropcall ) {
908 		childp -> propfraction += parentp -> propfraction
909 					* ( ( (double) arcp -> arc_count )
910 					  / ( (double) childp -> npropcall ) );
911 	    }
912 	}
913     } else {
914 	    /*
915 	     *	its a member of a cycle, look at all parents from
916 	     *	outside the cycle
917 	     */
918 	headp -> printflag = FALSE;
919 	headp -> propfraction = 0.0;
920 	for ( memp = headp -> cnext ; memp ; memp = memp -> cnext ) {
921 	    for (arcp = memp->parents ; arcp ; arcp = arcp->arc_parentlist) {
922 		if ( arcp -> arc_parentp -> cyclehead == headp ) {
923 		    continue;
924 		}
925 		parentp = arcp -> arc_parentp;
926 		headp -> printflag |= parentp -> printflag;
927 		    /*
928 		     *	if the cycle was never actually called
929 		     *	(e.g. this arc is static (and all others are, too))
930 		     *	no time propagates along this arc.
931 		     */
932 		if ( arcp -> arc_flags & DEADARC ) {
933 		    continue;
934 		}
935 		if ( headp -> npropcall ) {
936 		    headp -> propfraction += parentp -> propfraction
937 					* ( ( (double) arcp -> arc_count )
938 					  / ( (double) headp -> npropcall ) );
939 		}
940 	    }
941 	}
942 	for ( memp = headp ; memp ; memp = memp -> cnext ) {
943 	    memp -> printflag = headp -> printflag;
944 	    memp -> propfraction = headp -> propfraction;
945 	}
946     }
947 }
948