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
35 static char sccsid[] = "@(#)dfn.c 8.1 (Berkeley) 6/6/93";
46 typedef struct dfnstruct dfntype;
48 dfntype dfn_stack[ DFN_DEPTH ];
57 dfn_counter = DFN_NAN;
61 * given this parent, depth first number its children.
69 if ( debug & DFNDEBUG ) {
70 printf( "[dfn] dfn(" );
76 * if we're already numbered, no need to look any furthur.
78 if ( dfn_numbered( parentp ) ) {
82 * if we're already busy, must be a cycle
84 if ( dfn_busy( parentp ) ) {
85 dfn_findcycle( parentp );
89 * visit yourself before your children
91 dfn_pre_visit( parentp );
95 for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
96 if ( arcp -> arc_flags & DEADARC )
98 dfn( arcp -> arc_childp );
101 * visit yourself after your children
103 dfn_post_visit( parentp );
107 * push a parent onto the stack and mark it busy
109 dfn_pre_visit( parentp )
114 if ( dfn_depth >= DFN_DEPTH ) {
115 fprintf( stderr , "[dfn] out of my depth (dfn_stack overflow)\n" );
118 dfn_stack[ dfn_depth ].nlentryp = parentp;
119 dfn_stack[ dfn_depth ].cycletop = dfn_depth;
120 parentp -> toporder = DFN_BUSY;
122 if ( debug & DFNDEBUG ) {
123 printf( "[dfn_pre_visit]\t\t%d:" , dfn_depth );
124 printname( parentp );
131 * are we already numbered?
134 dfn_numbered( childp )
138 return ( childp -> toporder != DFN_NAN && childp -> toporder != DFN_BUSY );
142 * are we already busy?
149 if ( childp -> toporder == DFN_NAN ) {
156 * MISSING: an explanation
158 dfn_findcycle( childp )
166 for ( cycletop = dfn_depth ; cycletop > 0 ; cycletop -= 1 ) {
167 cycleheadp = dfn_stack[ cycletop ].nlentryp;
168 if ( childp == cycleheadp ) {
171 if ( childp -> cyclehead != childp &&
172 childp -> cyclehead == cycleheadp ) {
176 if ( cycletop <= 0 ) {
177 fprintf( stderr , "[dfn_findcycle] couldn't find head of cycle\n" );
181 if ( debug & DFNDEBUG ) {
182 printf( "[dfn_findcycle] dfn_depth %d cycletop %d " ,
183 dfn_depth , cycletop );
184 printname( cycleheadp );
188 if ( cycletop == dfn_depth ) {
190 * this is previous function, e.g. this calls itself
193 dfn_self_cycle( childp );
196 * glom intervening functions that aren't already
197 * glommed into this cycle.
198 * things have been glommed when their cyclehead field
199 * points to the head of the cycle they are glommed into.
201 for ( tailp = cycleheadp ; tailp -> cnext ; tailp = tailp -> cnext ) {
202 /* void: chase down to tail of things already glommed */
204 if ( debug & DFNDEBUG ) {
205 printf( "[dfn_findcycle] tail " );
212 * if what we think is the top of the cycle
213 * has a cyclehead field, then it's not really the
214 * head of the cycle, which is really what we want
216 if ( cycleheadp -> cyclehead != cycleheadp ) {
217 cycleheadp = cycleheadp -> cyclehead;
219 if ( debug & DFNDEBUG ) {
220 printf( "[dfn_findcycle] new cyclehead " );
221 printname( cycleheadp );
226 for ( index = cycletop + 1 ; index <= dfn_depth ; index += 1 ) {
227 childp = dfn_stack[ index ].nlentryp;
228 if ( childp -> cyclehead == childp ) {
230 * not yet glommed anywhere, glom it
231 * and fix any children it has glommed
233 tailp -> cnext = childp;
234 childp -> cyclehead = cycleheadp;
236 if ( debug & DFNDEBUG ) {
237 printf( "[dfn_findcycle] glomming " );
240 printname( cycleheadp );
244 for ( tailp = childp ; tailp->cnext ; tailp = tailp->cnext ) {
245 tailp -> cnext -> cyclehead = cycleheadp;
247 if ( debug & DFNDEBUG ) {
248 printf( "[dfn_findcycle] and its tail " );
249 printname( tailp -> cnext );
251 printname( cycleheadp );
256 } else if ( childp -> cyclehead != cycleheadp /* firewall */ ) {
258 "[dfn_busy] glommed, but not to cyclehead\n" );
265 * deal with self-cycles
268 dfn_self_cycle( parentp )
272 * since we are taking out self-cycles elsewhere
273 * no need for the special case, here.
276 if ( debug & DFNDEBUG ) {
277 printf( "[dfn_self_cycle] " );
278 printname( parentp );
285 * visit a node after all its children
286 * [MISSING: an explanation]
287 * and pop it off the stack
289 dfn_post_visit( parentp )
295 if ( debug & DFNDEBUG ) {
296 printf( "[dfn_post_visit]\t%d: " , dfn_depth );
297 printname( parentp );
302 * number functions and things in their cycles
303 * unless the function is itself part of a cycle
305 if ( parentp -> cyclehead == parentp ) {
307 for ( memberp = parentp ; memberp ; memberp = memberp -> cnext ) {
308 memberp -> toporder = dfn_counter;
310 if ( debug & DFNDEBUG ) {
311 printf( "[dfn_post_visit]\t\tmember " );
312 printname( memberp );
313 printf( " -> toporder = %d\n" , dfn_counter );
319 if ( debug & DFNDEBUG ) {
320 printf( "[dfn_post_visit]\t\tis part of a cycle\n" );