299 lines
7.9 KiB
C
299 lines
7.9 KiB
C
/*-
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* Copyright (c) 1983, 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/gmon.h>
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#ifdef _KERNEL
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#ifndef GUPROF
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#include <sys/systm.h>
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#endif
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#endif
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/*
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* mcount is called on entry to each function compiled with the profiling
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* switch set. _mcount(), which is declared in a machine-dependent way
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* with _MCOUNT_DECL, does the actual work and is either inlined into a
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* C routine or called by an assembly stub. In any case, this magic is
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* taken care of by the MCOUNT definition in <machine/profile.h>.
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*
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* _mcount updates data structures that represent traversals of the
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* program's call graph edges. frompc and selfpc are the return
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* address and function address that represents the given call graph edge.
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*
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* Note: the original BSD code used the same variable (frompcindex) for
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* both frompcindex and frompc. Any reasonable, modern compiler will
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* perform this optimization.
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*/
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_MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */
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uintfptr_t frompc, selfpc;
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{
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#ifdef GUPROF
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int delta;
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#endif
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fptrdiff_t frompci;
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u_short *frompcindex;
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struct tostruct *top, *prevtop;
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struct gmonparam *p;
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long toindex;
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#ifdef _KERNEL
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MCOUNT_DECL(s)
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#endif
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p = &_gmonparam;
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#ifndef GUPROF /* XXX */
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/*
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* check that we are profiling
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* and that we aren't recursively invoked.
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*/
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if (p->state != GMON_PROF_ON)
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return;
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#endif
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#ifdef _KERNEL
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MCOUNT_ENTER(s);
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#else
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p->state = GMON_PROF_BUSY;
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#endif
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#ifdef _KERNEL
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/*
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* When we are called from an exception handler, frompc may be
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* a user address. Convert such frompc's to some representation
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* in kernel address space.
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*/
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frompc = MCOUNT_FROMPC_USER(frompc);
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#endif
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frompci = frompc - p->lowpc;
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if (frompci >= p->textsize)
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goto done;
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#ifdef GUPROF
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if (p->state == GMON_PROF_HIRES) {
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/*
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* Count the time since cputime() was previously called
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* against `frompc'. Compensate for overheads.
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*
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* cputime() sets its prev_count variable to the count when
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* it is called. This in effect starts a counter for
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* the next period of execution (normally from now until
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* the next call to mcount() or mexitcount()). We set
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* cputime_bias to compensate for our own overhead.
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*
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* We use the usual sampling counters since they can be
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* located efficiently. 4-byte counters are usually
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* necessary. gprof will add up the scattered counts
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* just like it does for statistical profiling. All
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* counts are signed so that underflow in the subtractions
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* doesn't matter much (negative counts are normally
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* compensated for by larger counts elsewhere). Underflow
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* shouldn't occur, but may be caused by slightly wrong
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* calibrations or from not clearing cputime_bias.
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*/
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delta = cputime() - cputime_bias - p->mcount_pre_overhead;
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cputime_bias = p->mcount_post_overhead;
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KCOUNT(p, frompci) += delta;
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*p->cputime_count += p->cputime_overhead;
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*p->mcount_count += p->mcount_overhead;
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}
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#endif /* GUPROF */
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#ifdef _KERNEL
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/*
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* When we are called from an exception handler, frompc is faked
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* to be for where the exception occurred. We've just solidified
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* the count for there. Now convert frompci to an index that
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* represents the kind of exception so that interruptions appear
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* in the call graph as calls from those index instead of calls
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* from all over.
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*/
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frompc = MCOUNT_FROMPC_INTR(selfpc);
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if ((frompc - p->lowpc) < p->textsize)
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frompci = frompc - p->lowpc;
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#endif
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/*
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* check that frompc is a reasonable pc value.
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* for example: signal catchers get called from the stack,
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* not from text space. too bad.
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*/
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if (frompci >= p->textsize)
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goto done;
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frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))];
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toindex = *frompcindex;
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if (toindex == 0) {
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/*
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* first time traversing this arc
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*/
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toindex = ++p->tos[0].link;
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if (toindex >= p->tolimit)
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/* halt further profiling */
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goto overflow;
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*frompcindex = toindex;
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top = &p->tos[toindex];
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top->selfpc = selfpc;
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top->count = 1;
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top->link = 0;
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goto done;
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}
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top = &p->tos[toindex];
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if (top->selfpc == selfpc) {
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/*
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* arc at front of chain; usual case.
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*/
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top->count++;
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goto done;
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}
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/*
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* have to go looking down chain for it.
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* top points to what we are looking at,
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* prevtop points to previous top.
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* we know it is not at the head of the chain.
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*/
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for (; /* goto done */; ) {
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if (top->link == 0) {
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/*
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* top is end of the chain and none of the chain
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* had top->selfpc == selfpc.
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* so we allocate a new tostruct
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* and link it to the head of the chain.
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*/
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toindex = ++p->tos[0].link;
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if (toindex >= p->tolimit)
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goto overflow;
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top = &p->tos[toindex];
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top->selfpc = selfpc;
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top->count = 1;
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top->link = *frompcindex;
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*frompcindex = toindex;
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goto done;
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}
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/*
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* otherwise, check the next arc on the chain.
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*/
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prevtop = top;
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top = &p->tos[top->link];
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if (top->selfpc == selfpc) {
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/*
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* there it is.
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* increment its count
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* move it to the head of the chain.
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*/
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top->count++;
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toindex = prevtop->link;
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prevtop->link = top->link;
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top->link = *frompcindex;
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*frompcindex = toindex;
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goto done;
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}
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}
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done:
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#ifdef _KERNEL
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MCOUNT_EXIT(s);
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#else
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p->state = GMON_PROF_ON;
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#endif
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return;
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overflow:
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p->state = GMON_PROF_ERROR;
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#ifdef _KERNEL
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MCOUNT_EXIT(s);
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#endif
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return;
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}
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/*
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* Actual definition of mcount function. Defined in <machine/profile.h>,
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* which is included by <sys/gmon.h>.
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*/
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MCOUNT
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#ifdef GUPROF
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void
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mexitcount(selfpc)
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uintfptr_t selfpc;
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{
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struct gmonparam *p;
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uintfptr_t selfpcdiff;
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p = &_gmonparam;
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selfpcdiff = selfpc - (uintfptr_t)p->lowpc;
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if (selfpcdiff < p->textsize) {
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int delta;
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/*
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* Count the time since cputime() was previously called
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* against `selfpc'. Compensate for overheads.
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*/
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delta = cputime() - cputime_bias - p->mexitcount_pre_overhead;
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cputime_bias = p->mexitcount_post_overhead;
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KCOUNT(p, selfpcdiff) += delta;
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*p->cputime_count += p->cputime_overhead;
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*p->mexitcount_count += p->mexitcount_overhead;
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}
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}
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#ifndef __GNUCLIKE_ASM
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#error "This file uses null asms to prevent timing loops being optimized away."
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#endif
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void
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empty_loop()
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{
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int i;
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for (i = 0; i < CALIB_SCALE; i++)
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__asm __volatile("");
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}
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void
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nullfunc()
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{
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__asm __volatile("");
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}
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void
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nullfunc_loop()
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{
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int i;
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for (i = 0; i < CALIB_SCALE; i++)
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nullfunc();
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}
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#endif /* GUPROF */
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