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Diffstat (limited to 'sys/libkern/mcount.c')
| -rw-r--r-- | sys/libkern/mcount.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/sys/libkern/mcount.c b/sys/libkern/mcount.c new file mode 100644 index 000000000000..523217d1d2d9 --- /dev/null +++ b/sys/libkern/mcount.c @@ -0,0 +1,178 @@ +/*- + * Copyright (c) 1983, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS) +static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93"; +#endif + +#include <sys/param.h> +#include <sys/gmon.h> + +/* + * mcount is called on entry to each function compiled with the profiling + * switch set. _mcount(), which is declared in a machine-dependent way + * with _MCOUNT_DECL, does the actual work and is either inlined into a + * C routine or called by an assembly stub. In any case, this magic is + * taken care of by the MCOUNT definition in <machine/profile.h>. + * + * _mcount updates data structures that represent traversals of the + * program's call graph edges. frompc and selfpc are the return + * address and function address that represents the given call graph edge. + * + * Note: the original BSD code used the same variable (frompcindex) for + * both frompcindex and frompc. Any reasonable, modern compiler will + * perform this optimization. + */ +_MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ + register u_long frompc, selfpc; +{ + register u_short *frompcindex; + register struct tostruct *top, *prevtop; + register struct gmonparam *p; + register long toindex; +#ifdef KERNEL + register int s; +#endif + + p = &_gmonparam; + /* + * check that we are profiling + * and that we aren't recursively invoked. + */ + if (p->state != GMON_PROF_ON) + return; +#ifdef KERNEL + MCOUNT_ENTER; +#else + p->state = GMON_PROF_BUSY; +#endif + /* + * check that frompcindex is a reasonable pc value. + * for example: signal catchers get called from the stack, + * not from text space. too bad. + */ + frompc -= p->lowpc; + if (frompc > p->textsize) + goto done; + + frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))]; + toindex = *frompcindex; + if (toindex == 0) { + /* + * first time traversing this arc + */ + toindex = ++p->tos[0].link; + if (toindex >= p->tolimit) + /* halt further profiling */ + goto overflow; + + *frompcindex = toindex; + top = &p->tos[toindex]; + top->selfpc = selfpc; + top->count = 1; + top->link = 0; + goto done; + } + top = &p->tos[toindex]; + if (top->selfpc == selfpc) { + /* + * arc at front of chain; usual case. + */ + top->count++; + goto done; + } + /* + * have to go looking down chain for it. + * top points to what we are looking at, + * prevtop points to previous top. + * we know it is not at the head of the chain. + */ + for (; /* goto done */; ) { + if (top->link == 0) { + /* + * top is end of the chain and none of the chain + * had top->selfpc == selfpc. + * so we allocate a new tostruct + * and link it to the head of the chain. + */ + toindex = ++p->tos[0].link; + if (toindex >= p->tolimit) + goto overflow; + + top = &p->tos[toindex]; + top->selfpc = selfpc; + top->count = 1; + top->link = *frompcindex; + *frompcindex = toindex; + goto done; + } + /* + * otherwise, check the next arc on the chain. + */ + prevtop = top; + top = &p->tos[top->link]; + if (top->selfpc == selfpc) { + /* + * there it is. + * increment its count + * move it to the head of the chain. + */ + top->count++; + toindex = prevtop->link; + prevtop->link = top->link; + top->link = *frompcindex; + *frompcindex = toindex; + goto done; + } + + } +done: +#ifdef KERNEL + MCOUNT_EXIT; +#else + p->state = GMON_PROF_ON; +#endif + return; +overflow: + p->state = GMON_PROF_ERROR; +#ifdef KERNEL + MCOUNT_EXIT; +#endif + return; +} + +/* + * Actual definition of mcount function. Defined in <machine/profile.h>, + * which is included by <sys/gmon.h>. + */ +MCOUNT |