2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 static char sccsid[] = "@(#)dfn.c 8.1 (Berkeley) 6/6/93";
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
51 typedef struct dfnstruct dfntype;
53 dfntype dfn_stack[ DFN_DEPTH ];
63 dfn_counter = DFN_NAN;
67 * given this parent, depth first number its children.
76 if ( debug & DFNDEBUG ) {
77 printf( "[dfn] dfn(" );
83 * if we're already numbered, no need to look any further.
85 if ( dfn_numbered( parentp ) ) {
89 * if we're already busy, must be a cycle
91 if ( dfn_busy( parentp ) ) {
92 dfn_findcycle( parentp );
96 * visit yourself before your children
98 dfn_pre_visit( parentp );
102 for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
103 if ( arcp -> arc_flags & DEADARC )
105 dfn( arcp -> arc_childp );
108 * visit yourself after your children
110 dfn_post_visit( parentp );
114 * push a parent onto the stack and mark it busy
117 dfn_pre_visit( parentp )
122 if ( dfn_depth >= DFN_DEPTH )
123 errx( 1 , "[dfn] out of my depth (dfn_stack overflow)" );
124 dfn_stack[ dfn_depth ].nlentryp = parentp;
125 dfn_stack[ dfn_depth ].cycletop = dfn_depth;
126 parentp -> toporder = DFN_BUSY;
128 if ( debug & DFNDEBUG ) {
129 printf( "[dfn_pre_visit]\t\t%d:" , dfn_depth );
130 printname( parentp );
137 * are we already numbered?
140 dfn_numbered( childp )
144 return ( childp -> toporder != DFN_NAN && childp -> toporder != DFN_BUSY );
148 * are we already busy?
155 if ( childp -> toporder == DFN_NAN ) {
162 * MISSING: an explanation
165 dfn_findcycle( childp )
173 for ( cycletop = dfn_depth ; cycletop > 0 ; cycletop -= 1 ) {
174 cycleheadp = dfn_stack[ cycletop ].nlentryp;
175 if ( childp == cycleheadp ) {
178 if ( childp -> cyclehead != childp &&
179 childp -> cyclehead == cycleheadp ) {
184 errx( 1 , "[dfn_findcycle] couldn't find head of cycle" );
186 if ( debug & DFNDEBUG ) {
187 printf( "[dfn_findcycle] dfn_depth %d cycletop %d " ,
188 dfn_depth , cycletop );
189 printname( cycleheadp );
193 if ( cycletop == dfn_depth ) {
195 * this is previous function, e.g. this calls itself
198 dfn_self_cycle( childp );
201 * glom intervening functions that aren't already
202 * glommed into this cycle.
203 * things have been glommed when their cyclehead field
204 * points to the head of the cycle they are glommed into.
206 for ( tailp = cycleheadp ; tailp -> cnext ; tailp = tailp -> cnext ) {
207 /* void: chase down to tail of things already glommed */
209 if ( debug & DFNDEBUG ) {
210 printf( "[dfn_findcycle] tail " );
217 * if what we think is the top of the cycle
218 * has a cyclehead field, then it's not really the
219 * head of the cycle, which is really what we want
221 if ( cycleheadp -> cyclehead != cycleheadp ) {
222 cycleheadp = cycleheadp -> cyclehead;
224 if ( debug & DFNDEBUG ) {
225 printf( "[dfn_findcycle] new cyclehead " );
226 printname( cycleheadp );
231 for ( index = cycletop + 1 ; index <= dfn_depth ; index += 1 ) {
232 childp = dfn_stack[ index ].nlentryp;
233 if ( childp -> cyclehead == childp ) {
235 * not yet glommed anywhere, glom it
236 * and fix any children it has glommed
238 tailp -> cnext = childp;
239 childp -> cyclehead = cycleheadp;
241 if ( debug & DFNDEBUG ) {
242 printf( "[dfn_findcycle] glomming " );
245 printname( cycleheadp );
249 for ( tailp = childp ; tailp->cnext ; tailp = tailp->cnext ) {
250 tailp -> cnext -> cyclehead = cycleheadp;
252 if ( debug & DFNDEBUG ) {
253 printf( "[dfn_findcycle] and its tail " );
254 printname( tailp -> cnext );
256 printname( cycleheadp );
261 } else if ( childp -> cyclehead != cycleheadp /* firewall */ ) {
263 "[dfn_busy] glommed, but not to cyclehead\n" );
270 * deal with self-cycles
274 dfn_self_cycle( parentp )
278 * since we are taking out self-cycles elsewhere
279 * no need for the special case, here.
282 if ( debug & DFNDEBUG ) {
283 printf( "[dfn_self_cycle] " );
284 printname( parentp );
291 * visit a node after all its children
292 * [MISSING: an explanation]
293 * and pop it off the stack
296 dfn_post_visit( parentp )
302 if ( debug & DFNDEBUG ) {
303 printf( "[dfn_post_visit]\t%d: " , dfn_depth );
304 printname( parentp );
309 * number functions and things in their cycles
310 * unless the function is itself part of a cycle
312 if ( parentp -> cyclehead == parentp ) {
314 for ( memberp = parentp ; memberp ; memberp = memberp -> cnext ) {
315 memberp -> toporder = dfn_counter;
317 if ( debug & DFNDEBUG ) {
318 printf( "[dfn_post_visit]\t\tmember " );
319 printname( memberp );
320 printf( " -> toporder = %d\n" , dfn_counter );
326 if ( debug & DFNDEBUG ) {
327 printf( "[dfn_post_visit]\t\tis part of a cycle\n" );