xref: /illumos-gate/usr/src/cmd/sgs/gprof/common/dfn.c (revision 24fe0b3bf671e123467ce1df0b67cadd3614c8e4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 /*
24  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  */
27 
28 #pragma ident	"%Z%%M%	%I%	%E% SMI"
29 
30 #include <stdio.h>
31 #include "gprof.h"
32 
33 #define	DFN_DEPTH	100
34 
35 struct dfnstruct {
36 	nltype	*nlentryp;
37 	int	cycletop;
38 };
39 
40 typedef struct dfnstruct	dfntype;
41 
42 dfntype	*dfn_stack = NULL;
43 int	dfn_depth = 0;
44 int	dfn_sz = 0;
45 
46 int	dfn_counter = DFN_NAN;
47 
48 /*
49  *	given this parent, depth first number its children.
50  */
51 void
52 dfn(nltype *parentp)
53 {
54 	arctype	*arcp;
55 
56 #ifdef DEBUG
57 	if (debug & DFNDEBUG) {
58 		(void) printf("[dfn] dfn(");
59 		printname(parentp);
60 		(void) printf(")\n");
61 	}
62 #endif /* DEBUG */
63 
64 	if (!dfn_stack) {
65 		dfn_sz = DFN_DEPTH;
66 		dfn_stack = (dfntype *) malloc(dfn_sz * sizeof (dfntype));
67 		if (!dfn_stack) {
68 			(void) fprintf(stderr,
69 			    "fatal: can't malloc %d objects\n", dfn_sz);
70 			exit(1);
71 		}
72 	}
73 
74 	/*
75 	 *	if we're already numbered, no need to look any furthur.
76 	 */
77 	if (dfn_numbered(parentp))
78 		return;
79 
80 	/*
81 	 *	if we're already busy, must be a cycle
82 	 */
83 	if (dfn_busy(parentp)) {
84 		dfn_findcycle(parentp);
85 		return;
86 	}
87 
88 	/*
89 	 *	visit yourself before your children
90 	 */
91 	dfn_pre_visit(parentp);
92 
93 	/*
94 	 *	visit children
95 	 */
96 	for (arcp = parentp->children; arcp; arcp = arcp->arc_childlist)
97 		dfn(arcp->arc_childp);
98 
99 	/*
100 	 *	visit yourself after your children
101 	 */
102 	dfn_post_visit(parentp);
103 }
104 
105 /*
106  *	push a parent onto the stack and mark it busy
107  */
108 void
109 dfn_pre_visit(nltype *parentp)
110 {
111 
112 	if (!dfn_stack) {
113 		dfn_sz = DFN_DEPTH;
114 		dfn_stack = (dfntype *) malloc(dfn_sz * sizeof (dfntype));
115 		if (!dfn_stack) {
116 			(void) printf("fatal: can't malloc %d objects\n",
117 			    dfn_sz);
118 			exit(1);
119 		}
120 	}
121 
122 	dfn_depth += 1;
123 
124 	if (dfn_depth >= dfn_sz) {
125 		dfn_sz += DFN_DEPTH;
126 		dfn_stack = (dfntype *) realloc(dfn_stack,
127 		    dfn_sz * sizeof (dfntype));
128 
129 		if (!dfn_stack) {
130 			(void) fprintf(stderr,
131 			    "fatal: can't realloc %d objects\n", dfn_sz);
132 			exit(1);
133 		}
134 	}
135 
136 	dfn_stack[dfn_depth].nlentryp = parentp;
137 	dfn_stack[dfn_depth].cycletop = dfn_depth;
138 	parentp->toporder = DFN_BUSY;
139 
140 #ifdef DEBUG
141 	if (debug & DFNDEBUG) {
142 		(void) printf("[dfn_pre_visit]\t\t%d:", dfn_depth);
143 		printname(parentp);
144 		(void) printf("\n");
145 	}
146 #endif /* DEBUG */
147 }
148 
149 /*
150  *	are we already numbered?
151  */
152 bool
153 dfn_numbered(nltype *childp)
154 {
155 	return (childp->toporder != DFN_NAN && childp->toporder != DFN_BUSY);
156 }
157 
158 /*
159  *	are we already busy?
160  */
161 bool
162 dfn_busy(nltype *childp)
163 {
164 	if (childp->toporder == DFN_NAN)
165 		return (FALSE);
166 
167 	return (TRUE);
168 }
169 
170 void
171 dfn_findcycle(nltype *childp)
172 {
173 	int		cycletop;
174 	nltype	*cycleheadp;
175 	nltype	*tailp;
176 	int		index;
177 
178 	for (cycletop = dfn_depth; cycletop > 0; cycletop -= 1) {
179 		cycleheadp = dfn_stack[cycletop].nlentryp;
180 		if (childp == cycleheadp)
181 			break;
182 
183 		if (childp->cyclehead != childp &&
184 		    childp->cyclehead == cycleheadp)
185 			break;
186 	}
187 
188 	if (cycletop <= 0) {
189 		/*
190 		 * don't report non existent functions
191 		 */
192 		if (childp->value) {
193 			(void) fprintf(stderr,
194 			    "[dfn_findcycle] couldn't find head "
195 			    "of cycle for %s\n", childp->name);
196 			return;
197 		}
198 	}
199 
200 #ifdef DEBUG
201 	if (debug & DFNDEBUG) {
202 		(void) printf("[dfn_findcycle] dfn_depth %d cycletop %d ",
203 		    dfn_depth, cycletop);
204 		printname(cycleheadp);
205 		(void) printf("\n");
206 	}
207 #endif /* DEBUG */
208 
209 	if (cycletop == dfn_depth) {
210 		/*
211 		 *	this is previous function, e.g. this calls itself
212 		 *	sort of boring
213 		 */
214 		dfn_self_cycle(childp);
215 	} else {
216 		/*
217 		 *	glom intervening functions that aren't already
218 		 *	glommed into this cycle.
219 		 *	things have been glommed when their cyclehead field
220 		 *	points to the head of the cycle they are glommed into.
221 		 */
222 		for (tailp = cycleheadp; tailp->cnext; tailp = tailp->cnext) {
223 			/* void: chase down to tail of things already glommed */
224 #ifdef DEBUG
225 			if (debug & DFNDEBUG) {
226 				(void) printf("[dfn_findcycle] tail ");
227 				printname(tailp);
228 				(void) printf("\n");
229 			}
230 #endif /* DEBUG */
231 		}
232 
233 		/*
234 		 *	if what we think is the top of the cycle
235 		 *	has a cyclehead field, then it's not really the
236 		 *	head of the cycle, which is really what we want
237 		 */
238 		if (cycleheadp->cyclehead != cycleheadp) {
239 			cycleheadp = cycleheadp->cyclehead;
240 #ifdef DEBUG
241 			if (debug & DFNDEBUG) {
242 				(void) printf("[dfn_findcycle] new cyclehead ");
243 				printname(cycleheadp);
244 				(void) printf("\n");
245 			}
246 #endif /* DEBUG */
247 		}
248 
249 		for (index = cycletop + 1; index <= dfn_depth; index += 1) {
250 
251 			childp = dfn_stack[index].nlentryp;
252 			if (childp->cyclehead == childp) {
253 				/*
254 				 *	not yet glommed anywhere, glom it
255 				 *	and fix any children it has glommed
256 				 */
257 				tailp->cnext = childp;
258 				childp->cyclehead = cycleheadp;
259 #ifdef DEBUG
260 				if (debug & DFNDEBUG) {
261 					(void) printf(
262 					    "[dfn_findcycle] glomming ");
263 					printname(childp);
264 					(void) printf(" onto ");
265 					printname(cycleheadp);
266 					(void) printf("\n");
267 				}
268 #endif /* DEBUG */
269 				for (tailp = childp; tailp->cnext;
270 				    tailp = tailp->cnext) {
271 					tailp->cnext->cyclehead = cycleheadp;
272 #ifdef DEBUG
273 					if (debug & DFNDEBUG) {
274 						(void) printf("[dfn_findcycle]"
275 						    " and its tail ");
276 						printname(tailp->cnext);
277 						(void) printf(" onto ");
278 						printname(cycleheadp);
279 						(void) printf("\n");
280 					}
281 #endif /* DEBUG */
282 				}
283 			} else if (childp->cyclehead != cycleheadp) {
284 				(void) fprintf(stderr, "[dfn_busy] glommed,"
285 				    " but not to cyclehead\n");
286 			}
287 		}
288 	}
289 }
290 
291 /*
292  *	deal with self-cycles
293  *	for lint: ARGSUSED
294  */
295 /* ARGSUSED */
296 void
297 dfn_self_cycle(nltype *parentp)
298 {
299 	/*
300 	 *	since we are taking out self-cycles elsewhere
301 	 *	no need for the special case, here.
302 	 */
303 #ifdef DEBUG
304 	if (debug & DFNDEBUG) {
305 		(void) printf("[dfn_self_cycle] ");
306 		printname(parentp);
307 		(void) printf("\n");
308 	}
309 #endif /* DEBUG */
310 }
311 
312 /*
313  *	visit a node after all its children
314  *	[MISSING: an explanation]
315  *	and pop it off the stack
316  */
317 void
318 dfn_post_visit(nltype *parentp)
319 {
320 	nltype	*memberp;
321 
322 #ifdef DEBUG
323 	if (debug & DFNDEBUG) {
324 		(void) printf("[dfn_post_visit]\t%d: ", dfn_depth);
325 		printname(parentp);
326 		(void) printf("\n");
327 	}
328 #endif /* DEBUG */
329 	/*
330 	 *	number functions and things in their cycles
331 	 *	unless the function is itself part of a cycle
332 	 */
333 	if (parentp->cyclehead == parentp) {
334 		dfn_counter += 1;
335 
336 		for (memberp = parentp; memberp; memberp = memberp->cnext) {
337 
338 			memberp->toporder = dfn_counter;
339 #ifdef DEBUG
340 			if (debug & DFNDEBUG) {
341 				(void) printf("[dfn_post_visit]\t\tmember ");
342 				printname(memberp);
343 				(void) printf(" -> toporder = %d\n",
344 				    dfn_counter);
345 			}
346 #endif /* DEBUG */
347 		}
348 #ifdef DEBUG
349 	} else {
350 		if (debug & DFNDEBUG)
351 			(void) printf(
352 			    "[dfn_post_visit]\t\tis part of a cycle\n");
353 #endif /* DEBUG */
354 	}
355 	dfn_depth -= 1;
356 }
357