1 #ifndef lint 2 static char *sccsid = "@(#)dfn.c 1.3 (Berkeley) 01/15/83"; 3 #endif lint 4 5 #include <stdio.h> 6 #include "gprof.h" 7 8 #define DFN_DEPTH 100 9 struct dfnstruct { 10 nltype *nlentryp; 11 int cycletop; 12 }; 13 typedef struct dfnstruct dfntype; 14 15 dfntype dfn_stack[ DFN_DEPTH ]; 16 int dfn_depth = 0; 17 18 int dfn_counter = DFN_NAN; 19 20 /* 21 * given this parent, depth first number its children. 22 */ 23 dfn( parentp ) 24 nltype *parentp; 25 { 26 arctype *arcp; 27 28 # ifdef DEBUG 29 if ( debug & DFNDEBUG ) { 30 printf( "[dfn] dfn(" ); 31 printname( parentp ); 32 printf( ")\n" ); 33 } 34 # endif DEBUG 35 /* 36 * if we're already numbered, no need to look any furthur. 37 */ 38 if ( dfn_numbered( parentp ) ) { 39 return; 40 } 41 /* 42 * if we're already busy, must be a cycle 43 */ 44 if ( dfn_busy( parentp ) ) { 45 dfn_findcycle( parentp ); 46 return; 47 } 48 /* 49 * visit yourself before your children 50 */ 51 dfn_pre_visit( parentp ); 52 /* 53 * visit children 54 */ 55 for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) { 56 dfn( arcp -> arc_childp ); 57 } 58 /* 59 * visit yourself after your children 60 */ 61 dfn_post_visit( parentp ); 62 } 63 64 /* 65 * push a parent onto the stack and mark it busy 66 */ 67 dfn_pre_visit( parentp ) 68 nltype *parentp; 69 { 70 71 dfn_depth += 1; 72 if ( dfn_depth >= DFN_DEPTH ) { 73 fprintf( stderr , "[dfn] out of my depth (dfn_stack overflow)\n" ); 74 exit( 1 ); 75 } 76 dfn_stack[ dfn_depth ].nlentryp = parentp; 77 dfn_stack[ dfn_depth ].cycletop = dfn_depth; 78 parentp -> toporder = DFN_BUSY; 79 # ifdef DEBUG 80 if ( debug & DFNDEBUG ) { 81 printf( "[dfn_pre_visit]\t\t%d:" , dfn_depth ); 82 printname( parentp ); 83 printf( "\n" ); 84 } 85 # endif DEBUG 86 } 87 88 /* 89 * are we already numbered? 90 */ 91 bool 92 dfn_numbered( childp ) 93 nltype *childp; 94 { 95 96 return ( childp -> toporder != DFN_NAN && childp -> toporder != DFN_BUSY ); 97 } 98 99 /* 100 * are we already busy? 101 */ 102 bool 103 dfn_busy( childp ) 104 nltype *childp; 105 { 106 107 if ( childp -> toporder == DFN_NAN ) { 108 return FALSE; 109 } 110 return TRUE; 111 } 112 113 /* 114 * MISSING: an explanation 115 */ 116 dfn_findcycle( childp ) 117 nltype *childp; 118 { 119 int cycletop; 120 nltype *cycleheadp; 121 nltype *tailp; 122 int index; 123 124 for ( cycletop = dfn_depth ; cycletop > 0 ; cycletop -= 1 ) { 125 cycleheadp = dfn_stack[ cycletop ].nlentryp; 126 if ( childp == cycleheadp ) { 127 break; 128 } 129 if ( childp -> cyclehead != childp && 130 childp -> cyclehead == cycleheadp ) { 131 break; 132 } 133 } 134 if ( cycletop <= 0 ) { 135 fprintf( stderr , "[dfn_findcycle] couldn't find head of cycle\n" ); 136 exit( 1 ); 137 } 138 # ifdef DEBUG 139 if ( debug & DFNDEBUG ) { 140 printf( "[dfn_findcycle] dfn_depth %d cycletop %d " , 141 dfn_depth , cycletop ); 142 printname( cycleheadp ); 143 printf( "\n" ); 144 } 145 # endif DEBUG 146 if ( cycletop == dfn_depth ) { 147 /* 148 * this is previous function, e.g. this calls itself 149 * sort of boring 150 */ 151 dfn_self_cycle( childp ); 152 } else { 153 /* 154 * glom intervening functions that aren't already 155 * glommed into this cycle. 156 * things have been glommed when their cyclehead field 157 * points to the head of the cycle they are glommed into. 158 */ 159 for ( tailp = cycleheadp ; tailp -> cnext ; tailp = tailp -> cnext ) { 160 /* void: chase down to tail of things already glommed */ 161 # ifdef DEBUG 162 if ( debug & DFNDEBUG ) { 163 printf( "[dfn_findcycle] tail " ); 164 printname( tailp ); 165 printf( "\n" ); 166 } 167 # endif DEBUG 168 } 169 /* 170 * if what we think is the top of the cycle 171 * has a cyclehead field, then it's not really the 172 * head of the cycle, which is really what we want 173 */ 174 if ( cycleheadp -> cyclehead != cycleheadp ) { 175 cycleheadp = cycleheadp -> cyclehead; 176 # ifdef DEBUG 177 if ( debug & DFNDEBUG ) { 178 printf( "[dfn_findcycle] new cyclehead " ); 179 printname( cycleheadp ); 180 printf( "\n" ); 181 } 182 # endif DEBUG 183 } 184 for ( index = cycletop + 1 ; index <= dfn_depth ; index += 1 ) { 185 childp = dfn_stack[ index ].nlentryp; 186 if ( childp -> cyclehead == childp ) { 187 /* 188 * not yet glommed anywhere, glom it 189 * and fix any children it has glommed 190 */ 191 tailp -> cnext = childp; 192 childp -> cyclehead = cycleheadp; 193 # ifdef DEBUG 194 if ( debug & DFNDEBUG ) { 195 printf( "[dfn_findcycle] glomming " ); 196 printname( childp ); 197 printf( " onto " ); 198 printname( cycleheadp ); 199 printf( "\n" ); 200 } 201 # endif DEBUG 202 for ( tailp = childp ; tailp->cnext ; tailp = tailp->cnext ) { 203 tailp -> cnext -> cyclehead = cycleheadp; 204 # ifdef DEBUG 205 if ( debug & DFNDEBUG ) { 206 printf( "[dfn_findcycle] and its tail " ); 207 printname( tailp -> cnext ); 208 printf( " onto " ); 209 printname( cycleheadp ); 210 printf( "\n" ); 211 } 212 # endif DEBUG 213 } 214 } else if ( childp -> cyclehead != cycleheadp /* firewall */ ) { 215 fprintf( stderr , 216 "[dfn_busy] glommed, but not to cyclehead\n" ); 217 } 218 } 219 } 220 } 221 222 /* 223 * deal with self-cycles 224 * for lint: ARGSUSED 225 */ 226 dfn_self_cycle( parentp ) 227 nltype *parentp; 228 { 229 /* 230 * since we are taking out self-cycles elsewhere 231 * no need for the special case, here. 232 */ 233 # ifdef DEBUG 234 if ( debug & DFNDEBUG ) { 235 printf( "[dfn_self_cycle] " ); 236 printname( parentp ); 237 printf( "\n" ); 238 } 239 # endif DEBUG 240 } 241 242 /* 243 * visit a node after all its children 244 * [MISSING: an explanation] 245 * and pop it off the stack 246 */ 247 dfn_post_visit( parentp ) 248 nltype *parentp; 249 { 250 nltype *memberp; 251 252 # ifdef DEBUG 253 if ( debug & DFNDEBUG ) { 254 printf( "[dfn_post_visit]\t%d: " , dfn_depth ); 255 printname( parentp ); 256 printf( "\n" ); 257 } 258 # endif DEBUG 259 /* 260 * number functions and things in their cycles 261 * unless the function is itself part of a cycle 262 */ 263 if ( parentp -> cyclehead == parentp ) { 264 dfn_counter += 1; 265 for ( memberp = parentp ; memberp ; memberp = memberp -> cnext ) { 266 memberp -> toporder = dfn_counter; 267 # ifdef DEBUG 268 if ( debug & DFNDEBUG ) { 269 printf( "[dfn_post_visit]\t\tmember " ); 270 printname( memberp ); 271 printf( " -> toporder = %d\n" , dfn_counter ); 272 } 273 # endif DEBUG 274 } 275 } else { 276 # ifdef DEBUG 277 if ( debug & DFNDEBUG ) { 278 printf( "[dfn_post_visit]\t\tis part of a cycle\n" ); 279 } 280 # endif DEBUG 281 } 282 dfn_depth -= 1; 283 } 284