| 1 | /* Code to enable profiling at program startup. |
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| 2 | Copyright (C) 1995-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | In addition to the permissions in the GNU Lesser General Public |
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| 11 | License, the Free Software Foundation gives you unlimited |
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| 12 | permission to link the compiled version of this file with other |
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| 13 | programs, and to distribute those programs without any restriction |
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| 14 | coming from the use of this file. (The GNU Lesser General Public |
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| 15 | License restrictions do apply in other respects; for example, they |
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| 16 | cover modification of the file, and distribution when not linked |
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| 17 | into another program.) |
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| 18 | |
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| 19 | Note that people who make modified versions of this file are not |
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| 20 | obligated to grant this special exception for their modified |
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| 21 | versions; it is their choice whether to do so. The GNU Lesser |
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| 22 | General Public License gives permission to release a modified |
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| 23 | version without this exception; this exception also makes it |
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| 24 | possible to release a modified version which carries forward this |
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| 25 | exception. |
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| 26 | |
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| 27 | The GNU C Library is distributed in the hope that it will be useful, |
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| 28 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 29 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 30 | Lesser General Public License for more details. |
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| 31 | |
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| 32 | You should have received a copy of the GNU Lesser General Public |
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| 33 | License along with the GNU C Library; if not, see |
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| 34 | <https://www.gnu.org/licenses/>. */ |
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| 35 | |
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| 36 | #include <sys/types.h> |
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| 37 | #include <sys/gmon.h> |
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| 38 | #include <stdlib.h> |
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| 39 | #include <unistd.h> |
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| 40 | #include <elf-initfini.h> |
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| 41 | |
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| 42 | /* Use __executable_start as the lowest address to keep profiling records |
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| 43 | if it provided by the linker. */ |
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| 44 | extern const char __executable_start[] __attribute__ ((visibility ("hidden" ))); |
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| 45 | |
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| 46 | extern char etext[]; |
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| 47 | |
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| 48 | #if !ELF_INITFINI |
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| 49 | /* Instead of defining __gmon_start__ globally in gcrt1.o, we make it |
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| 50 | static and just put a pointer to it into the .preinit_array |
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| 51 | section. */ |
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| 52 | # define GMON_START_ARRAY_SECTION ".preinit_array" |
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| 53 | #endif |
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| 54 | |
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| 55 | #ifdef GMON_START_ARRAY_SECTION |
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| 56 | static void __gmon_start__ (void); |
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| 57 | static void (*const gmon_start_initializer) (void) |
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| 58 | __attribute__ ((used, section (GMON_START_ARRAY_SECTION))) = &__gmon_start__; |
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| 59 | static |
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| 60 | #else |
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| 61 | /* We cannot use the normal constructor mechanism to call |
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| 62 | __gmon_start__ because gcrt1.o appears before crtbegin.o in the link. |
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| 63 | Instead crti.o calls it specially. */ |
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| 64 | extern void __gmon_start__ (void); |
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| 65 | #endif |
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| 66 | |
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| 67 | void |
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| 68 | __gmon_start__ (void) |
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| 69 | { |
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| 70 | /* Protect from being called more than once. Since crti.o is linked |
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| 71 | into every shared library, each of their init functions will call us. */ |
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| 72 | static int called; |
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| 73 | |
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| 74 | if (called) |
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| 75 | return; |
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| 76 | |
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| 77 | called = 1; |
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| 78 | |
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| 79 | /* Start keeping profiling records. */ |
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| 80 | __monstartup (lowpc: (u_long) &__executable_start, highpc: (u_long) &etext); |
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| 81 | |
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| 82 | /* Call _mcleanup before exiting; it will write out gmon.out from the |
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| 83 | collected data. */ |
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| 84 | atexit (func: &_mcleanup); |
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| 85 | } |
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| 86 | |
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