xref: /titanic_51/usr/src/cmd/sgs/gprof/common/dfn.c (revision 8eea8e29cc4374d1ee24c25a07f45af132db3499)
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  * Copyright (c) 1990-1997,2001 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <stdio.h>
30 #include "gprof.h"
31 
32 #define	DFN_DEPTH	100
33 
34 struct dfnstruct {
35 	nltype	*nlentryp;
36 	int	cycletop;
37 };
38 
39 typedef struct dfnstruct	dfntype;
40 
41 dfntype	*dfn_stack = NULL;
42 int	dfn_depth = 0;
43 int	dfn_sz = 0;
44 
45 int	dfn_counter = DFN_NAN;
46 
47 /*
48  *	given this parent, depth first number its children.
49  */
50 void
51 dfn(nltype *parentp)
52 {
53 	arctype	*arcp;
54 
55 #ifdef DEBUG
56 	if (debug & DFNDEBUG) {
57 		printf("[dfn] dfn(");
58 		printname(parentp);
59 		printf(")\n");
60 	}
61 #endif /* DEBUG */
62 
63 	if (!dfn_stack) {
64 		dfn_sz = DFN_DEPTH;
65 		dfn_stack = (dfntype *) malloc(dfn_sz * sizeof (dfntype));
66 		if (!dfn_stack) {
67 			fprintf(stderr,
68 			    "fatal: can't malloc %d objects\n", dfn_sz);
69 			exit(1);
70 		}
71 	}
72 
73 	/*
74 	 *	if we're already numbered, no need to look any furthur.
75 	 */
76 	if (dfn_numbered(parentp))
77 		return;
78 
79 	/*
80 	 *	if we're already busy, must be a cycle
81 	 */
82 	if (dfn_busy(parentp)) {
83 		dfn_findcycle(parentp);
84 		return;
85 	}
86 
87 	/*
88 	 *	visit yourself before your children
89 	 */
90 	dfn_pre_visit(parentp);
91 
92 	/*
93 	 *	visit children
94 	 */
95 	for (arcp = parentp->children; arcp; arcp = arcp->arc_childlist)
96 		dfn(arcp->arc_childp);
97 
98 	/*
99 	 *	visit yourself after your children
100 	 */
101 	dfn_post_visit(parentp);
102 }
103 
104 /*
105  *	push a parent onto the stack and mark it busy
106  */
107 void
108 dfn_pre_visit(nltype *parentp)
109 {
110 
111 	if (!dfn_stack) {
112 		dfn_sz = DFN_DEPTH;
113 		dfn_stack = (dfntype *) malloc(dfn_sz * sizeof (dfntype));
114 		if (!dfn_stack) {
115 			printf("fatal: can't malloc %d objects\n", dfn_sz);
116 			exit(1);
117 		}
118 	}
119 
120 	dfn_depth += 1;
121 
122 	if (dfn_depth >= dfn_sz) {
123 		dfn_sz += DFN_DEPTH;
124 		dfn_stack = (dfntype *) realloc(dfn_stack,
125 		    dfn_sz * sizeof (dfntype));
126 
127 		if (!dfn_stack) {
128 			fprintf(stderr,
129 			    "fatal: can't realloc %d objects\n", dfn_sz);
130 			exit(1);
131 		}
132 	}
133 
134 	dfn_stack[dfn_depth].nlentryp = parentp;
135 	dfn_stack[dfn_depth].cycletop = dfn_depth;
136 	parentp->toporder = DFN_BUSY;
137 
138 #ifdef DEBUG
139 	if (debug & DFNDEBUG) {
140 		printf("[dfn_pre_visit]\t\t%d:", dfn_depth);
141 		printname(parentp);
142 		printf("\n");
143 	}
144 #endif /* DEBUG */
145 }
146 
147 /*
148  *	are we already numbered?
149  */
150 bool
151 dfn_numbered(nltype *childp)
152 {
153 	return (childp->toporder != DFN_NAN && childp->toporder != DFN_BUSY);
154 }
155 
156 /*
157  *	are we already busy?
158  */
159 bool
160 dfn_busy(nltype *childp)
161 {
162 	if (childp->toporder == DFN_NAN)
163 		return (FALSE);
164 
165 	return (TRUE);
166 }
167 
168 void
169 dfn_findcycle(nltype *childp)
170 {
171 	int		cycletop;
172 	nltype	*cycleheadp;
173 	nltype	*tailp;
174 	int		index;
175 
176 	for (cycletop = dfn_depth; cycletop > 0; cycletop -= 1) {
177 		cycleheadp = dfn_stack[cycletop].nlentryp;
178 		if (childp == cycleheadp)
179 			break;
180 
181 		if (childp->cyclehead != childp &&
182 		    childp->cyclehead == cycleheadp)
183 			break;
184 	}
185 
186 	if (cycletop <= 0) {
187 		/*
188 		 * don't report non existent functions
189 		 */
190 		if (childp->value) {
191 			fprintf(stderr, "[dfn_findcycle] couldn't find head "
192 			    "of cycle for %s\n", childp->name);
193 			return;
194 		}
195 	}
196 
197 #ifdef DEBUG
198 	if (debug & DFNDEBUG) {
199 		printf("[dfn_findcycle] dfn_depth %d cycletop %d ",
200 		    dfn_depth, cycletop);
201 		printname(cycleheadp);
202 		printf("\n");
203 	}
204 #endif /* DEBUG */
205 
206 	if (cycletop == dfn_depth) {
207 		/*
208 		 *	this is previous function, e.g. this calls itself
209 		 *	sort of boring
210 		 */
211 		dfn_self_cycle(childp);
212 	} else {
213 		/*
214 		 *	glom intervening functions that aren't already
215 		 *	glommed into this cycle.
216 		 *	things have been glommed when their cyclehead field
217 		 *	points to the head of the cycle they are glommed into.
218 		 */
219 		for (tailp = cycleheadp; tailp->cnext; tailp = tailp->cnext) {
220 			/* void: chase down to tail of things already glommed */
221 #ifdef DEBUG
222 			if (debug & DFNDEBUG) {
223 				printf("[dfn_findcycle] tail ");
224 				printname(tailp);
225 				printf("\n");
226 			}
227 #endif /* DEBUG */
228 		}
229 
230 		/*
231 		 *	if what we think is the top of the cycle
232 		 *	has a cyclehead field, then it's not really the
233 		 *	head of the cycle, which is really what we want
234 		 */
235 		if (cycleheadp->cyclehead != cycleheadp) {
236 			cycleheadp = cycleheadp->cyclehead;
237 #ifdef DEBUG
238 			if (debug & DFNDEBUG) {
239 				printf("[dfn_findcycle] new cyclehead ");
240 				printname(cycleheadp);
241 				printf("\n");
242 			}
243 #endif /* DEBUG */
244 		}
245 
246 		for (index = cycletop + 1; index <= dfn_depth; index += 1) {
247 
248 			childp = dfn_stack[index].nlentryp;
249 			if (childp->cyclehead == childp) {
250 				/*
251 				 *	not yet glommed anywhere, glom it
252 				 *	and fix any children it has glommed
253 				 */
254 				tailp->cnext = childp;
255 				childp->cyclehead = cycleheadp;
256 #ifdef DEBUG
257 				if (debug & DFNDEBUG) {
258 					printf("[dfn_findcycle] glomming ");
259 					printname(childp);
260 					printf(" onto ");
261 					printname(cycleheadp);
262 					printf("\n");
263 				}
264 #endif /* DEBUG */
265 				for (tailp = childp; tailp->cnext;
266 				    tailp = tailp->cnext) {
267 					tailp->cnext->cyclehead = cycleheadp;
268 #ifdef DEBUG
269 					if (debug & DFNDEBUG) {
270 						printf("[dfn_findcycle]"
271 						    " and its tail ");
272 						printname(tailp->cnext);
273 						printf(" onto ");
274 						printname(cycleheadp);
275 						printf("\n");
276 					}
277 #endif /* DEBUG */
278 				}
279 			} else if (childp->cyclehead != cycleheadp) {
280 				fprintf(stderr, "[dfn_busy] glommed,"
281 				    " but not to cyclehead\n");
282 			}
283 		}
284 	}
285 }
286 
287 /*
288  *	deal with self-cycles
289  *	for lint: ARGSUSED
290  */
291 /* ARGSUSED */
292 void
293 dfn_self_cycle(nltype *parentp)
294 {
295 	/*
296 	 *	since we are taking out self-cycles elsewhere
297 	 *	no need for the special case, here.
298 	 */
299 #ifdef DEBUG
300 	if (debug & DFNDEBUG) {
301 		printf("[dfn_self_cycle] ");
302 		printname(parentp);
303 		printf("\n");
304 	}
305 #endif /* DEBUG */
306 }
307 
308 /*
309  *	visit a node after all its children
310  *	[MISSING: an explanation]
311  *	and pop it off the stack
312  */
313 void
314 dfn_post_visit(nltype *parentp)
315 {
316 	nltype	*memberp;
317 
318 #ifdef DEBUG
319 	if (debug & DFNDEBUG) {
320 		printf("[dfn_post_visit]\t%d: ", dfn_depth);
321 		printname(parentp);
322 		printf("\n");
323 	}
324 #endif /* DEBUG */
325 	/*
326 	 *	number functions and things in their cycles
327 	 *	unless the function is itself part of a cycle
328 	 */
329 	if (parentp->cyclehead == parentp) {
330 		dfn_counter += 1;
331 
332 		for (memberp = parentp; memberp; memberp = memberp->cnext) {
333 
334 			memberp->toporder = dfn_counter;
335 #ifdef DEBUG
336 			if (debug & DFNDEBUG) {
337 				printf("[dfn_post_visit]\t\tmember ");
338 				printname(memberp);
339 				printf(" -> toporder = %d\n", dfn_counter);
340 			}
341 #endif /* DEBUG */
342 		}
343 #ifdef DEBUG
344 	} else {
345 		if (debug & DFNDEBUG)
346 			printf("[dfn_post_visit]\t\tis part of a cycle\n");
347 #endif /* DEBUG */
348 	}
349 	dfn_depth -= 1;
350 }
351