glibc/sysdeps/alpha/elf/initfini.c

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/* Special .init and .fini section support for Alpha.
Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* This file is compiled into assembly code which is then munged by a sed
script into two files: crti.s and crtn.s.
* crti.s puts a function prologue at the beginning of the .init and .fini
sections and defines global symbols for those addresses, so they can be
called as functions.
* crtn.s puts the corresponding function epilogues in the .init and .fini
sections.
This differs from what would be generated by the generic code in that
we save and restore the GP within the function. In order for linker
relaxation to work, the value in the GP register on exit from a function
must be valid for the function entry point. Normally, a function is
contained within one object file and this is not an issue, provided
that the function reloads the gp after making any function calls.
However, _init and _fini are constructed from pieces of many object
files, all of which may have different GP values. So we must reload
the GP value from crti.o in crtn.o. */
__asm__ (" \n\
#include \"defs.h\" \n\
\n\
/*@HEADER_ENDS*/ \n\
\n\
/*@_init_PROLOG_BEGINS*/ \n\
.section .init, \"ax\", @progbits \n\
.globl _init \n\
.type _init, @function \n\
.usepv _init, std \n\
_init: \n\
ldgp $29, 0($27) \n\
subq $30, 16, $30 \n\
lda $27, __gmon_start__ \n\
stq $26, 0($30) \n\
stq $29, 8($30) \n\
beq $27, 1f \n\
jsr $26, ($27), __gmon_start__ \n\
ldq $29, 8($30) \n\
.align 3 \n\
1: \n\
/*@_init_PROLOG_ENDS*/ \n\
\n\
/*@_init_EPILOG_BEGINS*/ \n\
.section .init, \"ax\", @progbits \n\
ldq $26, 0($30) \n\
ldq $29, 8($30) \n\
addq $30, 16, $30 \n\
ret \n\
/*@_init_EPILOG_ENDS*/ \n\
\n\
/*@_fini_PROLOG_BEGINS*/ \n\
.section .fini, \"ax\", @progbits \n\
.globl _fini \n\
.type _fini,@function \n\
.usepv _fini,std \n\
_fini: \n\
ldgp $29, 0($27) \n\
subq $30, 16, $30 \n\
stq $26, 0($30) \n\
stq $29, 8($30) \n\
.align 3 \n\
/*@_fini_PROLOG_ENDS*/ \n\
\n\
/*@_fini_EPILOG_BEGINS*/ \n\
.section .fini, \"ax\", @progbits \n\
ldq $26, 0($30) \n\
ldq $29, 8($30) \n\
addq $30, 16, $30 \n\
ret \n\
/*@_fini_EPILOG_ENDS*/ \n\
\n\
/*@TRAILER_BEGINS*/ \n\
");