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 "libiberty.h"
30#include "gprof.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
40typedef struct
41  {
42    Sym *sym;
43    int cycle_top;
44  }
45DFN_Stack;
46
47static bfd_boolean is_numbered PARAMS ((Sym *));
48static bfd_boolean is_busy PARAMS ((Sym *));
49static void find_cycle PARAMS ((Sym *));
50static void pre_visit PARAMS ((Sym *));
51static void post_visit PARAMS ((Sym *));
52
53DFN_Stack *dfn_stack = NULL;
54int dfn_maxdepth = 0;
55int dfn_depth = 0;
56int dfn_counter = DFN_NAN;
57
58
59/*
60 * Is CHILD already numbered?
61 */
62static bfd_boolean
63is_numbered (child)
64     Sym *child;
65{
66  return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY;
67}
68
69
70/*
71 * Is CHILD already busy?
72 */
73static bfd_boolean
74is_busy (child)
75     Sym *child;
76{
77  if (child->cg.top_order == DFN_NAN)
78    {
79      return FALSE;
80    }
81  return TRUE;
82}
83
84
85/*
86 * CHILD is part of a cycle.  Find the top caller into this cycle
87 * that is not part of the cycle and make all functions in cycle
88 * members of that cycle (top caller == caller with smallest
89 * depth-first number).
90 */
91static void
92find_cycle (child)
93     Sym *child;
94{
95  Sym *head = 0;
96  Sym *tail;
97  int cycle_top;
98  int index;
99
100  for (cycle_top = dfn_depth; cycle_top > 0; --cycle_top)
101    {
102      head = dfn_stack[cycle_top].sym;
103      if (child == head)
104	{
105	  break;
106	}
107      if (child->cg.cyc.head != child && child->cg.cyc.head == head)
108	{
109	  break;
110	}
111    }
112  if (cycle_top <= 0)
113    {
114      fprintf (stderr, "[find_cycle] couldn't find head of cycle\n");
115      done (1);
116    }
117#ifdef DEBUG
118  if (debug_level & DFNDEBUG)
119    {
120      printf ("[find_cycle] dfn_depth %d cycle_top %d ",
121	      dfn_depth, cycle_top);
122      if (head)
123	{
124	  print_name (head);
125	}
126      else
127	{
128	  printf ("<unknown>");
129	}
130      printf ("\n");
131    }
132#endif
133  if (cycle_top == dfn_depth)
134    {
135      /*
136       * This is previous function, e.g. this calls itself.  Sort of
137       * boring.
138       *
139       * Since we are taking out self-cycles elsewhere no need for
140       * the special case, here.
141       */
142      DBG (DFNDEBUG,
143	   printf ("[find_cycle] ");
144	   print_name (child);
145	   printf ("\n"));
146    }
147  else
148    {
149      /*
150       * Glom intervening functions that aren't already glommed into
151       * this cycle.  Things have been glommed when their cyclehead
152       * field points to the head of the cycle they are glommed
153       * into.
154       */
155      for (tail = head; tail->cg.cyc.next; tail = tail->cg.cyc.next)
156	{
157	  /* void: chase down to tail of things already glommed */
158	  DBG (DFNDEBUG,
159	       printf ("[find_cycle] tail ");
160	       print_name (tail);
161	       printf ("\n"));
162	}
163      /*
164       * If what we think is the top of the cycle has a cyclehead
165       * field, then it's not really the head of the cycle, which is
166       * really what we want.
167       */
168      if (head->cg.cyc.head != head)
169	{
170	  head = head->cg.cyc.head;
171	  DBG (DFNDEBUG, printf ("[find_cycle] new cyclehead ");
172	       print_name (head);
173	       printf ("\n"));
174	}
175      for (index = cycle_top + 1; index <= dfn_depth; ++index)
176	{
177	  child = dfn_stack[index].sym;
178	  if (child->cg.cyc.head == child)
179	    {
180	      /*
181	       * Not yet glommed anywhere, glom it and fix any
182	       * children it has glommed.
183	       */
184	      tail->cg.cyc.next = child;
185	      child->cg.cyc.head = head;
186	      DBG (DFNDEBUG, printf ("[find_cycle] glomming ");
187		   print_name (child);
188		   printf (" onto ");
189		   print_name (head);
190		   printf ("\n"));
191	      for (tail = child; tail->cg.cyc.next; tail = tail->cg.cyc.next)
192		{
193		  tail->cg.cyc.next->cg.cyc.head = head;
194		  DBG (DFNDEBUG, printf ("[find_cycle] and its tail ");
195		       print_name (tail->cg.cyc.next);
196		       printf (" onto ");
197		       print_name (head);
198		       printf ("\n"));
199		}
200	    }
201	  else if (child->cg.cyc.head != head /* firewall */ )
202	    {
203	      fprintf (stderr, "[find_cycle] glommed, but not to head\n");
204	      done (1);
205	    }
206	}
207    }
208}
209
210
211/*
212 * Prepare for visiting the children of PARENT.  Push a parent onto
213 * the stack and mark it busy.
214 */
215static void
216pre_visit (parent)
217     Sym *parent;
218{
219  ++dfn_depth;
220
221  if (dfn_depth >= dfn_maxdepth)
222    {
223      dfn_maxdepth += DFN_INCR_DEPTH;
224      dfn_stack = xrealloc (dfn_stack, dfn_maxdepth * sizeof *dfn_stack);
225    }
226
227  dfn_stack[dfn_depth].sym = parent;
228  dfn_stack[dfn_depth].cycle_top = dfn_depth;
229  parent->cg.top_order = DFN_BUSY;
230  DBG (DFNDEBUG, printf ("[pre_visit]\t\t%d:", dfn_depth);
231       print_name (parent);
232       printf ("\n"));
233}
234
235
236/*
237 * Done with visiting node PARENT.  Pop PARENT off dfn_stack
238 * and number functions if PARENT is head of a cycle.
239 */
240static void
241post_visit (parent)
242     Sym *parent;
243{
244  Sym *member;
245
246  DBG (DFNDEBUG, printf ("[post_visit]\t%d: ", dfn_depth);
247       print_name (parent);
248       printf ("\n"));
249  /*
250   * Number functions and things in their cycles unless the function
251   * is itself part of a cycle:
252   */
253  if (parent->cg.cyc.head == parent)
254    {
255      ++dfn_counter;
256      for (member = parent; member; member = member->cg.cyc.next)
257	{
258	  member->cg.top_order = dfn_counter;
259	  DBG (DFNDEBUG, printf ("[post_visit]\t\tmember ");
260	       print_name (member);
261	       printf ("-> cg.top_order = %d\n", dfn_counter));
262	}
263    }
264  else
265    {
266      DBG (DFNDEBUG, printf ("[post_visit]\t\tis part of a cycle\n"));
267    }
268  --dfn_depth;
269}
270
271
272/*
273 * Given this PARENT, depth first number its children.
274 */
275void
276cg_dfn (parent)
277     Sym *parent;
278{
279  Arc *arc;
280
281  DBG (DFNDEBUG, printf ("[dfn] dfn( ");
282       print_name (parent);
283       printf (")\n"));
284  /*
285   * If we're already numbered, no need to look any further:
286   */
287  if (is_numbered (parent))
288    {
289      return;
290    }
291  /*
292   * If we're already busy, must be a cycle:
293   */
294  if (is_busy (parent))
295    {
296      find_cycle (parent);
297      return;
298    }
299  pre_visit (parent);
300  /*
301   * Recursively visit children:
302   */
303  for (arc = parent->cg.children; arc; arc = arc->next_child)
304    {
305      cg_dfn (arc->child);
306    }
307  post_visit (parent);
308}
309