xref: /original-bsd/lib/libc/gmon/gmon.c (revision a91856c6)
1 /*-
2  * Copyright (c) 1983 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  */
7 
8 #ifndef lint
9 static char sccsid[] = "@(#)gmon.c	5.7 (Berkeley) 05/06/91";
10 #endif /* not lint */
11 
12 #include <unistd.h>
13 
14 #ifdef DEBUG
15 #include <stdio.h>
16 #endif
17 
18 #include "gmon.h"
19 
20 extern mcount() asm ("mcount");
21 extern mcount2() asm ("mcount2");
22 extern char *minbrk asm ("minbrk");
23 
24     /*
25      *	froms is actually a bunch of unsigned shorts indexing tos
26      */
27 static int		profiling = 3;
28 static unsigned short	*froms;
29 static struct tostruct	*tos = 0;
30 static long		tolimit = 0;
31 static char		*s_lowpc = 0;
32 static char		*s_highpc = 0;
33 static unsigned long	s_textsize = 0;
34 
35 static int	ssiz;
36 static char	*sbuf;
37 static int	s_scale;
38     /* see profil(2) where this is describe (incorrectly) */
39 #define		SCALE_1_TO_1	0x10000L
40 
41 #define	MSG "No space for monitor buffer(s)\n"
42 
43 monstartup(lowpc, highpc)
44     char	*lowpc;
45     char	*highpc;
46 {
47     int			monsize;
48     char		*buffer;
49 
50 	/*
51 	 *	round lowpc and highpc to multiples of the density we're using
52 	 *	so the rest of the scaling (here and in gprof) stays in ints.
53 	 */
54     lowpc = (char *)
55 	    ROUNDDOWN((unsigned)lowpc, HISTFRACTION*sizeof(HISTCOUNTER));
56     s_lowpc = lowpc;
57     highpc = (char *)
58 	    ROUNDUP((unsigned)highpc, HISTFRACTION*sizeof(HISTCOUNTER));
59     s_highpc = highpc;
60     s_textsize = highpc - lowpc;
61     monsize = (s_textsize / HISTFRACTION) + sizeof(struct phdr);
62     buffer = sbrk( monsize );
63     if ( buffer == (char *) -1 ) {
64 	write( 2 , MSG , sizeof(MSG) - 1 );
65 	return;
66     }
67     froms = (unsigned short *) sbrk( s_textsize / HASHFRACTION );
68     if ( froms == (unsigned short *) -1 ) {
69 	write( 2 , MSG , sizeof(MSG) - 1 );
70 	froms = 0;
71 	return;
72     }
73     tolimit = s_textsize * ARCDENSITY / 100;
74     if ( tolimit < MINARCS ) {
75 	tolimit = MINARCS;
76     } else if ( tolimit > 65534 ) {
77 	tolimit = 65534;
78     }
79     tos = (struct tostruct *) sbrk( tolimit * sizeof( struct tostruct ) );
80     if ( tos == (struct tostruct *) -1 ) {
81 	write( 2 , MSG , sizeof(MSG) - 1 );
82 	froms = 0;
83 	tos = 0;
84 	return;
85     }
86     minbrk = sbrk(0);
87     tos[0].link = 0;
88     monitor( lowpc , highpc , buffer , monsize , tolimit );
89 }
90 
91 _mcleanup()
92 {
93     int			fd;
94     int			fromindex;
95     int			endfrom;
96     char		*frompc;
97     int			toindex;
98     struct rawarc	rawarc;
99 
100     fd = creat( "gmon.out" , 0666 );
101     if ( fd < 0 ) {
102 	perror( "mcount: gmon.out" );
103 	return;
104     }
105 #   ifdef DEBUG
106 	fprintf( stderr , "[mcleanup] sbuf 0x%x ssiz %d\n" , sbuf , ssiz );
107 #   endif DEBUG
108     write( fd , sbuf , ssiz );
109     endfrom = s_textsize / (HASHFRACTION * sizeof(*froms));
110     for ( fromindex = 0 ; fromindex < endfrom ; fromindex++ ) {
111 	if ( froms[fromindex] == 0 ) {
112 	    continue;
113 	}
114 	frompc = s_lowpc + (fromindex * HASHFRACTION * sizeof(*froms));
115 	for (toindex=froms[fromindex]; toindex!=0; toindex=tos[toindex].link) {
116 #	    ifdef DEBUG
117 		fprintf( stderr ,
118 			"[mcleanup] frompc 0x%x selfpc 0x%x count %d\n" ,
119 			frompc , tos[toindex].selfpc , tos[toindex].count );
120 #	    endif DEBUG
121 	    rawarc.raw_frompc = (unsigned long) frompc;
122 	    rawarc.raw_selfpc = (unsigned long) tos[toindex].selfpc;
123 	    rawarc.raw_count = tos[toindex].count;
124 	    write( fd , &rawarc , sizeof rawarc );
125 	}
126     }
127     close( fd );
128 }
129 
130 asm(".text; .globl mcount; mcount: pushl 16(fp); calls $1,mcount2; rsb");
131 
132 mcount2(frompcindex, selfpc)
133 	register unsigned short		*frompcindex;
134 	register char			*selfpc;
135 {
136 	register struct tostruct	*top;
137 	register struct tostruct	*prevtop;
138 	register long			toindex;
139 
140 	/*
141 	 *	check that we are profiling
142 	 *	and that we aren't recursively invoked.
143 	 */
144 	if (profiling)
145 		return;
146 	profiling++;
147 	/*
148 	 *	check that frompcindex is a reasonable pc value.
149 	 *	for example:	signal catchers get called from the stack,
150 	 *			not from text space.  too bad.
151 	 */
152 	frompcindex = (unsigned short *)((long)frompcindex - (long)s_lowpc);
153 	if ((unsigned long)frompcindex > s_textsize) {
154 		goto done;
155 	}
156 	frompcindex =
157 	    &froms[((long)frompcindex) / (HASHFRACTION * sizeof(*froms))];
158 	toindex = *frompcindex;
159 	if (toindex == 0) {
160 		/*
161 		 *	first time traversing this arc
162 		 */
163 		toindex = ++tos[0].link;
164 		if (toindex >= tolimit) {
165 			goto overflow;
166 		}
167 		*frompcindex = toindex;
168 		top = &tos[toindex];
169 		top->selfpc = selfpc;
170 		top->count = 1;
171 		top->link = 0;
172 		goto done;
173 	}
174 	top = &tos[toindex];
175 	if (top->selfpc == selfpc) {
176 		/*
177 		 *	arc at front of chain; usual case.
178 		 */
179 		top->count++;
180 		goto done;
181 	}
182 	/*
183 	 *	have to go looking down chain for it.
184 	 *	top points to what we are looking at,
185 	 *	prevtop points to previous top.
186 	 *	we know it is not at the head of the chain.
187 	 */
188 	for (; /* goto done */; ) {
189 		if (top->link == 0) {
190 			/*
191 			 *	top is end of the chain and none of the chain
192 			 *	had top->selfpc == selfpc.
193 			 *	so we allocate a new tostruct
194 			 *	and link it to the head of the chain.
195 			 */
196 			toindex = ++tos[0].link;
197 			if (toindex >= tolimit) {
198 				goto overflow;
199 			}
200 			top = &tos[toindex];
201 			top->selfpc = selfpc;
202 			top->count = 1;
203 			top->link = *frompcindex;
204 			*frompcindex = toindex;
205 			goto done;
206 		}
207 		/*
208 		 *	otherwise, check the next arc on the chain.
209 		 */
210 		prevtop = top;
211 		top = &tos[top->link];
212 		if (top->selfpc == selfpc) {
213 			/*
214 			 *	there it is.
215 			 *	increment its count
216 			 *	move it to the head of the chain.
217 			 */
218 			top->count++;
219 			toindex = prevtop->link;
220 			prevtop->link = top->link;
221 			top->link = *frompcindex;
222 			*frompcindex = toindex;
223 			goto done;
224 		}
225 
226 	}
227 done:
228 	profiling--;
229 	return;
230 
231 overflow:
232 	profiling++; /* halt further profiling */
233 #   define	TOLIMIT	"mcount: tos overflow\n"
234 	write(2, TOLIMIT, sizeof(TOLIMIT) - 1);
235 	return;
236 }
237 
238 /*VARARGS1*/
239 monitor( lowpc , highpc , buf , bufsiz , nfunc )
240     char	*lowpc;
241     char	*highpc;
242     char	*buf;	/* declared ``short buffer[]'' in monitor(3) */
243     int		bufsiz;
244     int		nfunc;	/* not used, available for compatability only */
245 {
246     register o;
247 
248     if ( lowpc == 0 ) {
249 	moncontrol(0);
250 	_mcleanup();
251 	return;
252     }
253     sbuf = buf;
254     ssiz = bufsiz;
255     ( (struct phdr *) buf ) -> lpc = lowpc;
256     ( (struct phdr *) buf ) -> hpc = highpc;
257     ( (struct phdr *) buf ) -> ncnt = ssiz;
258     bufsiz -= sizeof(struct phdr);
259     if ( bufsiz <= 0 )
260 	return;
261     o = highpc - lowpc;
262     if( bufsiz < o )
263 	s_scale = ( (float) bufsiz / o ) * SCALE_1_TO_1;
264     else
265 	s_scale = SCALE_1_TO_1;
266     moncontrol(1);
267 }
268 
269 /*
270  * Control profiling
271  *	profiling is what mcount checks to see if
272  *	all the data structures are ready.
273  */
274 moncontrol(mode)
275     int mode;
276 {
277     if (mode) {
278 	/* start */
279 	profil(sbuf + sizeof(struct phdr), ssiz - sizeof(struct phdr),
280 		(int)s_lowpc, s_scale);
281 	profiling = 0;
282     } else {
283 	/* stop */
284 	profil((char *)0, 0, 0, 0);
285 	profiling = 3;
286     }
287 }
288