glibc/csu/gmon-start.c

62 lines
2.2 KiB
C

/* Code to enable profiling at program startup.
Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sys/types.h>
#include <sys/gmon.h>
#include <stdlib.h>
#include <unistd.h>
/* Beginning and end of our code segment. We cannot declare them
as the external functions since we want the addresses of those
labels. Taking the address of a function may have different
meanings on different platforms. */
extern void _start, etext;
#ifndef HAVE_INITFINI
/* This function gets called at startup by the normal constructor
mechanism. We link this file together with start.o to produce gcrt1.o,
so this constructor will be first in the list. */
void __gmon_start__ (void) __attribute__ ((constructor));
#else
/* In ELF and COFF, we cannot use the normal constructor mechanism to call
__gmon_start__ because gcrt1.o appears before crtbegin.o in the link.
Instead crti.o calls it specially (see initfini.c). */
#endif
void
__gmon_start__ (void)
{
#ifdef HAVE_INITFINI
/* Protect from being called more than once. Since crti.o is linked
into every shared library, each of their init functions will call us. */
static int called;
if (called++)
return;
#endif
/* Start keeping profiling records. */
__monstartup ((u_long) &_start, (u_long) &etext);
/* Call _mcleanup before exiting; it will write out gmon.out from the
collected data. */
atexit (&_mcleanup);
}