1/* Code to enable profiling at program startup.
2 Copyright (C) 1995-2020 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 In addition to the permissions in the GNU Lesser General Public
11 License, the Free Software Foundation gives you unlimited
12 permission to link the compiled version of this file with other
13 programs, and to distribute those programs without any restriction
14 coming from the use of this file. (The GNU Lesser General Public
15 License restrictions do apply in other respects; for example, they
16 cover modification of the file, and distribution when not linked
17 into another program.)
18
19 Note that people who make modified versions of this file are not
20 obligated to grant this special exception for their modified
21 versions; it is their choice whether to do so. The GNU Lesser
22 General Public License gives permission to release a modified
23 version without this exception; this exception also makes it
24 possible to release a modified version which carries forward this
25 exception.
26
27 The GNU C Library is distributed in the hope that it will be useful,
28 but WITHOUT ANY WARRANTY; without even the implied warranty of
29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 Lesser General Public License for more details.
31
32 You should have received a copy of the GNU Lesser General Public
33 License along with the GNU C Library; if not, see
34 <https://www.gnu.org/licenses/>. */
35
36#include <sys/types.h>
37#include <sys/gmon.h>
38#include <stdlib.h>
39#include <unistd.h>
40#include <elf-initfini.h>
41#define __ASSEMBLY__
42#include <entry.h>
43
44/* Beginning and end of our code segment. We cannot declare them
45 as the external functions since we want the addresses of those
46 labels. Taking the address of a function may have different
47 meanings on different platforms. */
48#ifdef ENTRY_POINT_DECL
49ENTRY_POINT_DECL(extern)
50#else
51extern char ENTRY_POINT[];
52#endif
53extern char etext[];
54
55#ifndef TEXT_START
56# ifdef ENTRY_POINT_DECL
57# define TEXT_START ENTRY_POINT
58# else
59# define TEXT_START &ENTRY_POINT
60# endif
61#endif
62
63#if !ELF_INITFINI
64/* Instead of defining __gmon_start__ globally in gcrt1.o, we make it
65 static and just put a pointer to it into the .preinit_array
66 section. */
67# define GMON_START_ARRAY_SECTION ".preinit_array"
68#endif
69
70#ifdef GMON_START_ARRAY_SECTION
71static void __gmon_start__ (void);
72static void (*const gmon_start_initializer) (void)
73 __attribute__ ((used, section (GMON_START_ARRAY_SECTION))) = &__gmon_start__;
74static
75#else
76/* We cannot use the normal constructor mechanism to call
77 __gmon_start__ because gcrt1.o appears before crtbegin.o in the link.
78 Instead crti.o calls it specially. */
79extern void __gmon_start__ (void);
80#endif
81
82void
83__gmon_start__ (void)
84{
85 /* Protect from being called more than once. Since crti.o is linked
86 into every shared library, each of their init functions will call us. */
87 static int called;
88
89 if (called)
90 return;
91
92 called = 1;
93
94 /* Start keeping profiling records. */
95 __monstartup ((u_long) TEXT_START, (u_long) &etext);
96
97 /* Call _mcleanup before exiting; it will write out gmon.out from the
98 collected data. */
99 atexit (&_mcleanup);
100}
101