1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 #include "gprof.h" 30 #include "libiberty.h" 31 #include "search_list.h" 32 #include "source.h" 33 #include "symtab.h" 34 #include "cg_arcs.h" 35 #include "cg_dfn.h" 36 #include "utils.h" 37 38 #define DFN_INCR_DEPTH (128) 39 40 typedef struct 41 { 42 Sym *sym; 43 int cycle_top; 44 } 45 DFN_Stack; 46 47 static bfd_boolean is_numbered (Sym *); 48 static bfd_boolean is_busy (Sym *); 49 static void find_cycle (Sym *); 50 static void pre_visit (Sym *); 51 static void post_visit (Sym *); 52 53 DFN_Stack *dfn_stack = NULL; 54 int dfn_maxdepth = 0; 55 int dfn_depth = 0; 56 int dfn_counter = DFN_NAN; 57 58 59 /* 60 * Is CHILD already numbered? 61 */ 62 static bfd_boolean 63 is_numbered (Sym *child) 64 { 65 return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY; 66 } 67 68 69 /* 70 * Is CHILD already busy? 71 */ 72 static bfd_boolean 73 is_busy (Sym *child) 74 { 75 if (child->cg.top_order == DFN_NAN) 76 { 77 return FALSE; 78 } 79 return TRUE; 80 } 81 82 83 /* 84 * CHILD is part of a cycle. Find the top caller into this cycle 85 * that is not part of the cycle and make all functions in cycle 86 * members of that cycle (top caller == caller with smallest 87 * depth-first number). 88 */ 89 static void 90 find_cycle (Sym *child) 91 { 92 Sym *head = 0; 93 Sym *tail; 94 int cycle_top; 95 int cycle_index; 96 97 for (cycle_top = dfn_depth; cycle_top > 0; --cycle_top) 98 { 99 head = dfn_stack[cycle_top].sym; 100 if (child == head) 101 { 102 break; 103 } 104 if (child->cg.cyc.head != child && child->cg.cyc.head == head) 105 { 106 break; 107 } 108 } 109 if (cycle_top <= 0) 110 { 111 fprintf (stderr, "[find_cycle] couldn't find head of cycle\n"); 112 done (1); 113 } 114 #ifdef DEBUG 115 if (debug_level & DFNDEBUG) 116 { 117 printf ("[find_cycle] dfn_depth %d cycle_top %d ", 118 dfn_depth, cycle_top); 119 if (head) 120 { 121 print_name (head); 122 } 123 else 124 { 125 printf ("<unknown>"); 126 } 127 printf ("\n"); 128 } 129 #endif 130 if (cycle_top == dfn_depth) 131 { 132 /* 133 * This is previous function, e.g. this calls itself. Sort of 134 * boring. 135 * 136 * Since we are taking out self-cycles elsewhere no need for 137 * the special case, here. 138 */ 139 DBG (DFNDEBUG, 140 printf ("[find_cycle] "); 141 print_name (child); 142 printf ("\n")); 143 } 144 else 145 { 146 /* 147 * Glom intervening functions that aren't already glommed into 148 * this cycle. Things have been glommed when their cyclehead 149 * field points to the head of the cycle they are glommed 150 * into. 151 */ 152 for (tail = head; tail->cg.cyc.next; tail = tail->cg.cyc.next) 153 { 154 /* void: chase down to tail of things already glommed */ 155 DBG (DFNDEBUG, 156 printf ("[find_cycle] tail "); 157 print_name (tail); 158 printf ("\n")); 159 } 160 /* 161 * If what we think is the top of the cycle has a cyclehead 162 * field, then it's not really the head of the cycle, which is 163 * really what we want. 164 */ 165 if (head->cg.cyc.head != head) 166 { 167 head = head->cg.cyc.head; 168 DBG (DFNDEBUG, printf ("[find_cycle] new cyclehead "); 169 print_name (head); 170 printf ("\n")); 171 } 172 for (cycle_index = cycle_top + 1; cycle_index <= dfn_depth; ++cycle_index) 173 { 174 child = dfn_stack[cycle_index].sym; 175 if (child->cg.cyc.head == child) 176 { 177 /* 178 * Not yet glommed anywhere, glom it and fix any 179 * children it has glommed. 180 */ 181 tail->cg.cyc.next = child; 182 child->cg.cyc.head = head; 183 DBG (DFNDEBUG, printf ("[find_cycle] glomming "); 184 print_name (child); 185 printf (" onto "); 186 print_name (head); 187 printf ("\n")); 188 for (tail = child; tail->cg.cyc.next; tail = tail->cg.cyc.next) 189 { 190 tail->cg.cyc.next->cg.cyc.head = head; 191 DBG (DFNDEBUG, printf ("[find_cycle] and its tail "); 192 print_name (tail->cg.cyc.next); 193 printf (" onto "); 194 print_name (head); 195 printf ("\n")); 196 } 197 } 198 else if (child->cg.cyc.head != head /* firewall */ ) 199 { 200 fprintf (stderr, "[find_cycle] glommed, but not to head\n"); 201 done (1); 202 } 203 } 204 } 205 } 206 207 208 /* 209 * Prepare for visiting the children of PARENT. Push a parent onto 210 * the stack and mark it busy. 211 */ 212 static void 213 pre_visit (Sym *parent) 214 { 215 ++dfn_depth; 216 217 if (dfn_depth >= dfn_maxdepth) 218 { 219 dfn_maxdepth += DFN_INCR_DEPTH; 220 dfn_stack = (DFN_Stack *) xrealloc (dfn_stack, 221 dfn_maxdepth * sizeof *dfn_stack); 222 } 223 224 dfn_stack[dfn_depth].sym = parent; 225 dfn_stack[dfn_depth].cycle_top = dfn_depth; 226 parent->cg.top_order = DFN_BUSY; 227 DBG (DFNDEBUG, printf ("[pre_visit]\t\t%d:", dfn_depth); 228 print_name (parent); 229 printf ("\n")); 230 } 231 232 233 /* 234 * Done with visiting node PARENT. Pop PARENT off dfn_stack 235 * and number functions if PARENT is head of a cycle. 236 */ 237 static void 238 post_visit (Sym *parent) 239 { 240 Sym *member; 241 242 DBG (DFNDEBUG, printf ("[post_visit]\t%d: ", dfn_depth); 243 print_name (parent); 244 printf ("\n")); 245 /* 246 * Number functions and things in their cycles unless the function 247 * is itself part of a cycle: 248 */ 249 if (parent->cg.cyc.head == parent) 250 { 251 ++dfn_counter; 252 for (member = parent; member; member = member->cg.cyc.next) 253 { 254 member->cg.top_order = dfn_counter; 255 DBG (DFNDEBUG, printf ("[post_visit]\t\tmember "); 256 print_name (member); 257 printf ("-> cg.top_order = %d\n", dfn_counter)); 258 } 259 } 260 else 261 { 262 DBG (DFNDEBUG, printf ("[post_visit]\t\tis part of a cycle\n")); 263 } 264 --dfn_depth; 265 } 266 267 268 /* 269 * Given this PARENT, depth first number its children. 270 */ 271 void 272 cg_dfn (Sym *parent) 273 { 274 Arc *arc; 275 276 DBG (DFNDEBUG, printf ("[dfn] dfn( "); 277 print_name (parent); 278 printf (")\n")); 279 /* 280 * If we're already numbered, no need to look any further: 281 */ 282 if (is_numbered (parent)) 283 { 284 return; 285 } 286 /* 287 * If we're already busy, must be a cycle: 288 */ 289 if (is_busy (parent)) 290 { 291 find_cycle (parent); 292 return; 293 } 294 pre_visit (parent); 295 /* 296 * Recursively visit children: 297 */ 298 for (arc = parent->cg.children; arc; arc = arc->next_child) 299 { 300 cg_dfn (arc->child); 301 } 302 post_visit (parent); 303 } 304
