csu/gmon-start.c

   1 /* Code to enable profiling at program startup.
   2    Copyright (C) 1995,1996,1997,2000,2001,2002,2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <sys/types.h>
  21 #include <sys/gmon.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #define __ASSEMBLY__
  25 #include <entry.h>
  26
  27 /* Beginning and end of our code segment. We cannot declare them
  28    as the external functions since we want the addresses of those
  29    labels. Taking the address of a function may have different
  30    meanings on different platforms. */
  31 #ifdef ENTRY_POINT_DECL
  32 ENTRY_POINT_DECL(extern)
  33 #else
  34 extern char ENTRY_POINT[];
  35 #endif
  36 extern char etext[];
  37
  38 #ifndef TEXT_START
  39 # ifdef ENTRY_POINT_DECL
  40 #  define TEXT_START ENTRY_POINT
  41 # else
  42 #  define TEXT_START &ENTRY_POINT
  43 # endif
  44 #endif
  45
  46 /* We cannot use the normal constructor mechanism to call
  47    __gmon_start__ because gcrt1.o appears before crtbegin.o in the link.
  48    Instead crti.o calls it specially.  */
  49 extern void __gmon_start__ (void);
  50
  51 void
  52 __gmon_start__ (void)
  53 {
  54   /* Protect from being called more than once.  Since crti.o is linked
  55      into every shared library, each of their init functions will call us.  */
  56   static int called;
  57
  58   if (called)
  59     return;
  60
  61   called = 1;
  62
  63   /* Start keeping profiling records.  */
  64   __monstartup ((u_long) TEXT_START, (u_long) &etext);
  65
  66   /* Call _mcleanup before exiting; it will write out gmon.out from the
  67      collected data.  */
  68   atexit (&_mcleanup);
  69 }