| 1 | /* |
| 2 | * Copyright (c) 1983 Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms are permitted |
| 6 | * provided that: (1) source distributions retain this entire copyright |
| 7 | * notice and comment, and (2) distributions including binaries display |
| 8 | * the following acknowledgement: ``This product includes software |
| 9 | * developed by the University of California, Berkeley and its contributors'' |
| 10 | * in the documentation or other materials provided with the distribution |
| 11 | * and in all advertising materials mentioning features or use of this |
| 12 | * software. Neither the name of the University nor the names of its |
| 13 | * contributors may be used to endorse or promote products derived |
| 14 | * from this software without specific prior written permission. |
| 15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
| 17 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 18 | */ |
| 19 | #include <stdio.h> |
| 20 | #include "gprof.h" |
| 21 | #include "cg_arcs.h" |
| 22 | #include "cg_dfn.h" |
| 23 | #include "symtab.h" |
| 24 | #include "utils.h" |
| 25 | |
| 26 | #define DFN_DEPTH 100 |
| 27 | |
| 28 | typedef struct |
| 29 | { |
| 30 | Sym *sym; |
| 31 | int cycle_top; |
| 32 | } |
| 33 | DFN_Stack; |
| 34 | |
| 35 | DFN_Stack dfn_stack[DFN_DEPTH]; |
| 36 | int dfn_depth = 0; |
| 37 | int dfn_counter = DFN_NAN; |
| 38 | |
| 39 | |
| 40 | /* |
| 41 | * Is CHILD already numbered? |
| 42 | */ |
| 43 | static bool |
| 44 | DEFUN (is_numbered, (child), Sym * child) |
| 45 | { |
| 46 | return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY; |
| 47 | } |
| 48 | |
| 49 | |
| 50 | /* |
| 51 | * Is CHILD already busy? |
| 52 | */ |
| 53 | static bool |
| 54 | DEFUN (is_busy, (child), Sym * child) |
| 55 | { |
| 56 | if (child->cg.top_order == DFN_NAN) |
| 57 | { |
| 58 | return FALSE; |
| 59 | } |
| 60 | return TRUE; |
| 61 | } |
| 62 | |
| 63 | |
| 64 | /* |
| 65 | * CHILD is part of a cycle. Find the top caller into this cycle |
| 66 | * that is not part of the cycle and make all functions in cycle |
| 67 | * members of that cycle (top caller == caller with smallest |
| 68 | * depth-first number). |
| 69 | */ |
| 70 | static void |
| 71 | DEFUN (find_cycle, (child), Sym * child) |
| 72 | { |
| 73 | Sym *head = 0; |
| 74 | Sym *tail; |
| 75 | int cycle_top; |
| 76 | int index; |
| 77 | |
| 78 | for (cycle_top = dfn_depth; cycle_top > 0; --cycle_top) |
| 79 | { |
| 80 | head = dfn_stack[cycle_top].sym; |
| 81 | if (child == head) |
| 82 | { |
| 83 | break; |
| 84 | } |
| 85 | if (child->cg.cyc.head != child && child->cg.cyc.head == head) |
| 86 | { |
| 87 | break; |
| 88 | } |
| 89 | } |
| 90 | if (cycle_top <= 0) |
| 91 | { |
| 92 | fprintf (stderr, "[find_cycle] couldn't find head of cycle\n"); |
| 93 | done (1); |
| 94 | } |
| 95 | #ifdef DEBUG |
| 96 | if (debug_level & DFNDEBUG) |
| 97 | { |
| 98 | printf ("[find_cycle] dfn_depth %d cycle_top %d ", |
| 99 | dfn_depth, cycle_top); |
| 100 | if (head) |
| 101 | { |
| 102 | print_name (head); |
| 103 | } |
| 104 | else |
| 105 | { |
| 106 | printf ("<unknown>"); |
| 107 | } |
| 108 | printf ("\n"); |
| 109 | } |
| 110 | #endif |
| 111 | if (cycle_top == dfn_depth) |
| 112 | { |
| 113 | /* |
| 114 | * This is previous function, e.g. this calls itself. Sort of |
| 115 | * boring. |
| 116 | * |
| 117 | * Since we are taking out self-cycles elsewhere no need for |
| 118 | * the special case, here. |
| 119 | */ |
| 120 | DBG (DFNDEBUG, |
| 121 | printf ("[find_cycle] "); |
| 122 | print_name (child); |
| 123 | printf ("\n")); |
| 124 | } |
| 125 | else |
| 126 | { |
| 127 | /* |
| 128 | * Glom intervening functions that aren't already glommed into |
| 129 | * this cycle. Things have been glommed when their cyclehead |
| 130 | * field points to the head of the cycle they are glommed |
| 131 | * into. |
| 132 | */ |
| 133 | for (tail = head; tail->cg.cyc.next; tail = tail->cg.cyc.next) |
| 134 | { |
| 135 | /* void: chase down to tail of things already glommed */ |
| 136 | DBG (DFNDEBUG, |
| 137 | printf ("[find_cycle] tail "); |
| 138 | print_name (tail); |
| 139 | printf ("\n")); |
| 140 | } |
| 141 | /* |
| 142 | * If what we think is the top of the cycle has a cyclehead |
| 143 | * field, then it's not really the head of the cycle, which is |
| 144 | * really what we want. |
| 145 | */ |
| 146 | if (head->cg.cyc.head != head) |
| 147 | { |
| 148 | head = head->cg.cyc.head; |
| 149 | DBG (DFNDEBUG, printf ("[find_cycle] new cyclehead "); |
| 150 | print_name (head); |
| 151 | printf ("\n")); |
| 152 | } |
| 153 | for (index = cycle_top + 1; index <= dfn_depth; ++index) |
| 154 | { |
| 155 | child = dfn_stack[index].sym; |
| 156 | if (child->cg.cyc.head == child) |
| 157 | { |
| 158 | /* |
| 159 | * Not yet glommed anywhere, glom it and fix any |
| 160 | * children it has glommed. |
| 161 | */ |
| 162 | tail->cg.cyc.next = child; |
| 163 | child->cg.cyc.head = head; |
| 164 | DBG (DFNDEBUG, printf ("[find_cycle] glomming "); |
| 165 | print_name (child); |
| 166 | printf (" onto "); |
| 167 | print_name (head); |
| 168 | printf ("\n")); |
| 169 | for (tail = child; tail->cg.cyc.next; tail = tail->cg.cyc.next) |
| 170 | { |
| 171 | tail->cg.cyc.next->cg.cyc.head = head; |
| 172 | DBG (DFNDEBUG, printf ("[find_cycle] and its tail "); |
| 173 | print_name (tail->cg.cyc.next); |
| 174 | printf (" onto "); |
| 175 | print_name (head); |
| 176 | printf ("\n")); |
| 177 | } |
| 178 | } |
| 179 | else if (child->cg.cyc.head != head /* firewall */ ) |
| 180 | { |
| 181 | fprintf (stderr, "[find_cycle] glommed, but not to head\n"); |
| 182 | done (1); |
| 183 | } |
| 184 | } |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | |
| 189 | /* |
| 190 | * Prepare for visiting the children of PARENT. Push a parent onto |
| 191 | * the stack and mark it busy. |
| 192 | */ |
| 193 | static void |
| 194 | DEFUN (pre_visit, (parent), Sym * parent) |
| 195 | { |
| 196 | ++dfn_depth; |
| 197 | if (dfn_depth >= DFN_DEPTH) |
| 198 | { |
| 199 | fprintf (stderr, "[pre_visit] dfn_stack overflow\n"); |
| 200 | done (1); |
| 201 | } |
| 202 | dfn_stack[dfn_depth].sym = parent; |
| 203 | dfn_stack[dfn_depth].cycle_top = dfn_depth; |
| 204 | parent->cg.top_order = DFN_BUSY; |
| 205 | DBG (DFNDEBUG, printf ("[pre_visit]\t\t%d:", dfn_depth); |
| 206 | print_name (parent); |
| 207 | printf ("\n")); |
| 208 | } |
| 209 | |
| 210 | |
| 211 | /* |
| 212 | * Done with visiting node PARENT. Pop PARENT off dfn_stack |
| 213 | * and number functions if PARENT is head of a cycle. |
| 214 | */ |
| 215 | static void |
| 216 | DEFUN (post_visit, (parent), Sym * parent) |
| 217 | { |
| 218 | Sym *member; |
| 219 | |
| 220 | DBG (DFNDEBUG, printf ("[post_visit]\t%d: ", dfn_depth); |
| 221 | print_name (parent); |
| 222 | printf ("\n")); |
| 223 | /* |
| 224 | * Number functions and things in their cycles unless the function |
| 225 | * is itself part of a cycle: |
| 226 | */ |
| 227 | if (parent->cg.cyc.head == parent) |
| 228 | { |
| 229 | ++dfn_counter; |
| 230 | for (member = parent; member; member = member->cg.cyc.next) |
| 231 | { |
| 232 | member->cg.top_order = dfn_counter; |
| 233 | DBG (DFNDEBUG, printf ("[post_visit]\t\tmember "); |
| 234 | print_name (member); |
| 235 | printf ("-> cg.top_order = %d\n", dfn_counter)); |
| 236 | } |
| 237 | } |
| 238 | else |
| 239 | { |
| 240 | DBG (DFNDEBUG, printf ("[post_visit]\t\tis part of a cycle\n")); |
| 241 | } |
| 242 | --dfn_depth; |
| 243 | } |
| 244 | |
| 245 | |
| 246 | /* |
| 247 | * Given this PARENT, depth first number its children. |
| 248 | */ |
| 249 | void |
| 250 | DEFUN (cg_dfn, (parent), Sym * parent) |
| 251 | { |
| 252 | Arc *arc; |
| 253 | |
| 254 | DBG (DFNDEBUG, printf ("[dfn] dfn( "); |
| 255 | print_name (parent); |
| 256 | printf (")\n")); |
| 257 | /* |
| 258 | * If we're already numbered, no need to look any further: |
| 259 | */ |
| 260 | if (is_numbered (parent)) |
| 261 | { |
| 262 | return; |
| 263 | } |
| 264 | /* |
| 265 | * If we're already busy, must be a cycle: |
| 266 | */ |
| 267 | if (is_busy (parent)) |
| 268 | { |
| 269 | find_cycle (parent); |
| 270 | return; |
| 271 | } |
| 272 | pre_visit (parent); |
| 273 | /* |
| 274 | * Recursively visit children: |
| 275 | */ |
| 276 | for (arc = parent->cg.children; arc; arc = arc->next_child) |
| 277 | { |
| 278 | cg_dfn (arc->child); |
| 279 | } |
| 280 | post_visit (parent); |
| 281 | } |