132 lines
4.6 KiB
C
132 lines
4.6 KiB
C
/* Special .init and .fini section support.
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Copyright (C) 1995, 1996 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 and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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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
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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/* This file is compiled into assembly code which is then surrounded by the
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lines `cat > crtcommon.tmp <<\EOF_common' and `EOF_common' and thus
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becomes a shell script which creates three files of assembly code.
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* The first file is crti.s-new; this puts a function prologue at the
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beginning of the .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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* The second file is crtn.s-new; this puts the corresponding function
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epilogues in the .init and .fini sections.
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* The third file is crtcommon.tmp, which is whatever miscellaneous cruft
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the compiler generated at the end; it should be appended to both crti.s-new
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and crtn.s-new. */
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#include <stdlib.h>
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#ifdef HAVE_ELF
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/* These declarations make the functions go in the right sections when
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we define them below. GCC syntax does not allow the attribute
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specifications to be in the function definitions themselves. */
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void _init (void) __attribute__ ((section (".init")));
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void _fini (void) __attribute__ ((section (".fini")));
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#define SECTION(x) /* Put nothing extra before the defn. */
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#else
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/* Some non-ELF systems support .init and .fini sections,
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but the __attribute__ syntax only works for ELF. */
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#define SECTION(x) asm (".section " x);
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#endif
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/* End the here document containing the initial common code.
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Then move the output file crtcommon.tmp to crti.s-new and crtn.s-new. */
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asm ("\nEOF_common\n\
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rm -f crti.s-new crtn.s-new\n\
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mv crtcommon.tmp crti.s-new\n\
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cp crti.s-new crtn.s-new");
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/* Extract a `.end' if one is produced by the compiler. */
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asm ("fgrep .end >/dev/null 2>&1 <<\\EOF.end && need_end=yes");
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void
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useless_function (void)
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{
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return;
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}
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asm ("\nEOF.end\n");
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/* Append the .init prologue to crti.s-new. */
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asm ("cat >> crti.s-new <<\\EOF.crti.init");
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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); weak_extern (__gmon_start__)
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if (__gmon_start__)
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__gmon_start__ ();
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/* End the here document containing the .init prologue code.
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Then fetch the .section directive just written and append that
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to crtn.s-new, followed by the function epilogue. */
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asm ("\n\
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EOF.crti.init\n\
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test -n \"$need_end\" && echo .end _init >> crti.s-new\n\
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fgrep .init crti.s-new >>crtn.s-new\n\
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fgrep -v .end >> crtn.s-new <<\\EOF.crtn.init");
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}
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/* End the here document containing the .init epilogue code.
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Then append the .fini prologue to crti.s-new. */
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asm ("\nEOF.crtn.init\
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\n\
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cat >> crti.s-new <<\\EOF.crti.fini");
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SECTION (".fini")
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void
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_fini (void)
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{
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/* End the here document containing the .fini prologue code.
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Then fetch the .section directive just written and append that
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to crtn.s-new, followed by the function epilogue. */
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asm ("\nEOF.crti.fini\n\
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test -n \"$need_end\" && echo .end _fini >> crti.s-new\n\
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cat > /dev/null <<\\EOF.fini.skip");
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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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asm ("\nEOF.fini.skip\
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\n\
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fgrep .fini crti.s-new >>crtn.s-new\n\
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fgrep -v .end >> crtn.s-new <<\\EOF.crtn.fini");
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}
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/* End the here document containing the .fini epilogue code.
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Finally, put the remainder of the generated assembly into crtcommon.tmp. */
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asm ("\nEOF.crtn.fini\
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\n\
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cat > crtcommon.tmp <<\\EOF_common");
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