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freebsd/lib/csu/i386-elf/crt1.c
Bruce Evans d31f7e4991 Fixed profiling of main() for amd64 and i386. This started rotting
in 1993 in rev.1.5 of the i386 a.out version (csu/i386/crt0.c).
Profiling uses a magic label "eprol" to delimit the start of the part
of the text section covered by profiling.  This label must be placed
before the call to main() to get main() properly profiled.  It was
placed there in rev.1.1 of crt0.c.  Rev.1.5 imported the initial
implementation of shared libraries in FreeBSD and misplaced the label.
Fortunately, the misplaced label was misspelled and the old label
wasn't removed, so the new label had no effect.  Unfortunately, when
profiling was implemented for the ELF in 1998 in rev.1.2 of
csu/i386-elf/crt1.c, only the incorrectly placed label was copied
(after fixing its name).  The bug was then copied to all other arches.
The label seems to be still misplaced in NetBSD for most arches.  It
is in common.c for most arches so it is even further from being inside
the function that calls main().

I think "eprol" is short for "end of prologue", but it must be placed
before the end of the prologue so that it covers main().  crt0.c has
it before the calls atexit(_mcleanup) and monstartup(...), but it
cannot affect these calls so I moved it after the call to monstartup().
It now also covers the call to _init() but not the newer call to
_init_tls().  Profiling of _init() seems to be harmless, and the call
to _init_tls() seems to be misplaced.

Reviewed by:	jdp (long ago, for a slightly different i386 version)
2005-10-07 22:13:17 +00:00

114 lines
2.7 KiB
C

/* LINTLIBRARY */
/*-
* Copyright 1996-1998 John D. Polstra.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#ifndef lint
#ifndef __GNUC__
#error "GCC is needed to compile this file"
#endif
#endif /* lint */
#include <stdlib.h>
#include "libc_private.h"
#include "crtbrand.c"
extern int _DYNAMIC;
#pragma weak _DYNAMIC
typedef void (*fptr)(void);
extern void _fini(void);
extern void _init(void);
extern int main(int, char **, char **);
extern void _start(char *, ...);
#ifdef GCRT
extern void _mcleanup(void);
extern void monstartup(void *, void *);
extern int eprol;
extern int etext;
#endif
char **environ;
const char *__progname = "";
static __inline fptr
get_rtld_cleanup(void)
{
fptr retval;
#ifdef __GNUC__
__asm__("movl %%edx,%0" : "=rm"(retval));
#else
retval = (fptr)0; /* XXXX Fix this for other compilers */
#endif
return(retval);
}
/* The entry function. */
void
_start(char *ap, ...)
{
fptr cleanup;
int argc;
char **argv;
char **env;
const char *s;
#ifdef __GNUC__
__asm__("and $0xfffffff0,%esp");
#endif
cleanup = get_rtld_cleanup();
argv = &ap;
argc = *(long *)(void *)(argv - 1);
env = argv + argc + 1;
environ = env;
if (argc > 0 && argv[0] != NULL) {
__progname = argv[0];
for (s = __progname; *s != '\0'; s++)
if (*s == '/')
__progname = s + 1;
}
if (&_DYNAMIC != NULL)
atexit(cleanup);
else
_init_tls();
#ifdef GCRT
atexit(_mcleanup);
#endif
atexit(_fini);
#ifdef GCRT
monstartup(&eprol, &etext);
__asm__("eprol:");
#endif
_init();
exit( main(argc, argv, env) );
}
__asm__(".ident\t\"$FreeBSD$\"");