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1997-04-18 02:18 Ulrich Drepper <drepper@cygnus.com> * csu/initfini.c: Rewrite by Zack Weinberg <zack@rabi.phys.columbia.edu>. * csu/Makefile: Add rules for rewrite. * csu/defs.awk: Helper script to generate derived header.
123 lines
4.0 KiB
C
123 lines
4.0 KiB
C
/* Special .init and .fini section support.
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Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it
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and/or modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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In addition to the permissions in the GNU Library General Public
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License, the Free Software Foundation gives you unlimited
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permission to link the compiled version of this file with other
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programs, and to distribute those programs without any restriction
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coming from the use of this file. (The Library General Public
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License restrictions do apply in other respects; for example, they
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cover modification of the file, and distribution when not linked
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into another program.)
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The GNU C Library is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This file is compiled into assembly code which is then munged by a sed
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script into two files: crti.s and crtn.s.
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* crti.s puts a function prologue at the beginning of the
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.init and .fini sections and defines global symbols for
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those addresses, so they can be called as functions.
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* crtn.s puts the corresponding function epilogues
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in the .init and .fini sections. */
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#include <stdlib.h>
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/* We use embedded asm for .section unconditionally, as this makes it
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easier to insert the necessary directives into crtn.S. */
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#define SECTION(x) asm (".section \"" x "\"");
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/* Embed an #include to pull in the alignment and .end directives. */
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asm ("\n#include \"defs.h\"");
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/* The initial common code ends here. */
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asm ("\n/*@HEADER_ENDS*/");
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/* To determine whether we need .end and .align: */
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asm ("\n/*@TESTS_BEGIN*/");
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void
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dummy (void (*foo) (void))
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{
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if (foo)
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(*foo) ();
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}
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asm ("\n/*@TESTS_END*/");
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/* The beginning of _init: */
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asm ("\n/*@_init_PROLOG_BEGINS*/");
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SECTION (".init")
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void
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_init (void)
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{
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/* We cannot use the normal constructor mechanism in gcrt1.o because it
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appears before crtbegin.o in the link, so the header elt of .ctors
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would come after the elt for __gmon_start__. One approach is for
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gcrt1.o to reference a symbol which would be defined by some library
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module which has a constructor; but then user code's constructors
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would come first, and not be profiled. */
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extern void __gmon_start__ (void) __attribute__ ((weak)); /*weak_extern (__gmon_start__);*/
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if (__gmon_start__)
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__gmon_start__ ();
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asm("END_INIT");
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/* Now the epilog. */
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asm ("\n/*@_init_PROLOG_ENDS*/");
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asm ("\n/*@_init_EPILOG_BEGINS*/");
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SECTION(".init");
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asm ("ALIGN");
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}
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asm ("END_INIT");
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/* End of the _init epilog, beginning of the _fini prolog. */
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asm ("\n/*@_init_EPILOG_ENDS*/");
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asm ("\n/*@_fini_PROLOG_BEGINS*/");
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SECTION (".fini")
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void
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_fini (void)
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{
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/* End of the _fini prolog. */
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asm ("END_FINI");
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asm ("\n/*@_fini_PROLOG_ENDS*/");
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{
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/* Let GCC know that _fini is not a leaf function by having a dummy
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function call here. We arrange for this call to be omitted from
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either crt file. */
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extern void i_am_not_a_leaf (void);
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i_am_not_a_leaf ();
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}
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/* Beginning of the _fini epilog. */
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asm ("\n/*@_fini_EPILOG_BEGINS*/");
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SECTION (".fini");
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asm ("ALIGN");
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}
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asm ("END_FINI");
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/* End of the _fini epilog. Any further generated assembly (e.g. .ident)
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is shared between both crt files. */
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asm ("\n/*@_fini_EPILOG_ENDS*/");
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asm ("\n/*@TRAILER_BEGINS*/");
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asm ("ALIGN");
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/* End of file. */
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