2 * Copyright (c) 1983, 1993
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32 static char sccsid[] = "@(#)dfn.c 8.1 (Berkeley) 6/6/93";
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
47 typedef struct dfnstruct dfntype;
49 dfntype dfn_stack[ DFN_DEPTH ];
59 dfn_counter = DFN_NAN;
63 * given this parent, depth first number its children.
71 if ( debug & DFNDEBUG ) {
72 printf( "[dfn] dfn(" );
78 * if we're already numbered, no need to look any further.
80 if ( dfn_numbered( parentp ) ) {
84 * if we're already busy, must be a cycle
86 if ( dfn_busy( parentp ) ) {
87 dfn_findcycle( parentp );
91 * visit yourself before your children
93 dfn_pre_visit( parentp );
97 for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
98 if ( arcp -> arc_flags & DEADARC )
100 dfn( arcp -> arc_childp );
103 * visit yourself after your children
105 dfn_post_visit( parentp );
109 * push a parent onto the stack and mark it busy
112 dfn_pre_visit(nltype *parentp)
116 if ( dfn_depth >= DFN_DEPTH )
117 errx( 1 , "[dfn] out of my depth (dfn_stack overflow)" );
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(nltype *childp)
137 return ( childp -> toporder != DFN_NAN && childp -> toporder != DFN_BUSY );
141 * are we already busy?
144 dfn_busy(nltype *childp)
147 if ( childp -> toporder == DFN_NAN ) {
154 * MISSING: an explanation
157 dfn_findcycle(nltype *childp)
164 for ( cycletop = dfn_depth ; cycletop > 0 ; cycletop -= 1 ) {
165 cycleheadp = dfn_stack[ cycletop ].nlentryp;
166 if ( childp == cycleheadp ) {
169 if ( childp -> cyclehead != childp &&
170 childp -> cyclehead == cycleheadp ) {
175 errx( 1 , "[dfn_findcycle] couldn't find head of cycle" );
177 if ( debug & DFNDEBUG ) {
178 printf( "[dfn_findcycle] dfn_depth %d cycletop %d " ,
179 dfn_depth , cycletop );
180 printname( cycleheadp );
184 if ( cycletop == dfn_depth ) {
186 * this is previous function, e.g. this calls itself
189 dfn_self_cycle( childp );
192 * glom intervening functions that aren't already
193 * glommed into this cycle.
194 * things have been glommed when their cyclehead field
195 * points to the head of the cycle they are glommed into.
197 for ( tailp = cycleheadp ; tailp -> cnext ; tailp = tailp -> cnext ) {
198 /* void: chase down to tail of things already glommed */
200 if ( debug & DFNDEBUG ) {
201 printf( "[dfn_findcycle] tail " );
208 * if what we think is the top of the cycle
209 * has a cyclehead field, then it's not really the
210 * head of the cycle, which is really what we want
212 if ( cycleheadp -> cyclehead != cycleheadp ) {
213 cycleheadp = cycleheadp -> cyclehead;
215 if ( debug & DFNDEBUG ) {
216 printf( "[dfn_findcycle] new cyclehead " );
217 printname( cycleheadp );
222 for ( index = cycletop + 1 ; index <= dfn_depth ; index += 1 ) {
223 childp = dfn_stack[ index ].nlentryp;
224 if ( childp -> cyclehead == childp ) {
226 * not yet glommed anywhere, glom it
227 * and fix any children it has glommed
229 tailp -> cnext = childp;
230 childp -> cyclehead = cycleheadp;
232 if ( debug & DFNDEBUG ) {
233 printf( "[dfn_findcycle] glomming " );
236 printname( cycleheadp );
240 for ( tailp = childp ; tailp->cnext ; tailp = tailp->cnext ) {
241 tailp -> cnext -> cyclehead = cycleheadp;
243 if ( debug & DFNDEBUG ) {
244 printf( "[dfn_findcycle] and its tail " );
245 printname( tailp -> cnext );
247 printname( cycleheadp );
252 } else if ( childp -> cyclehead != cycleheadp /* firewall */ ) {
254 "[dfn_busy] glommed, but not to cyclehead\n" );
261 * deal with self-cycles
265 dfn_self_cycle(nltype *parentp)
268 * since we are taking out self-cycles elsewhere
269 * no need for the special case, here.
272 if ( debug & DFNDEBUG ) {
273 printf( "[dfn_self_cycle] " );
274 printname( parentp );
281 * visit a node after all its children
282 * [MISSING: an explanation]
283 * and pop it off the stack
286 dfn_post_visit(nltype *parentp)
291 if ( debug & DFNDEBUG ) {
292 printf( "[dfn_post_visit]\t%d: " , dfn_depth );
293 printname( parentp );
298 * number functions and things in their cycles
299 * unless the function is itself part of a cycle
301 if ( parentp -> cyclehead == parentp ) {
303 for ( memberp = parentp ; memberp ; memberp = memberp -> cnext ) {
304 memberp -> toporder = dfn_counter;
306 if ( debug & DFNDEBUG ) {
307 printf( "[dfn_post_visit]\t\tmember " );
308 printname( memberp );
309 printf( " -> toporder = %d\n" , dfn_counter );
315 if ( debug & DFNDEBUG ) {
316 printf( "[dfn_post_visit]\t\tis part of a cycle\n" );