Blame sysdeps/hppa/crti.S

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/* Special .init and .fini section support for HPPA
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   Copyright (C) 2000-2018 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 Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   In addition to the permissions in the GNU Lesser 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 GNU Lesser 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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   Note that people who make modified versions of this file are not
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   obligated to grant this special exception for their modified
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   versions; it is their choice whether to do so. The GNU Lesser
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   General Public License gives permission to release a modified
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   version without this exception; this exception also makes it
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   possible to release a modified version which carries forward this
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   exception.
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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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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library.  If not, see
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   <http://www.gnu.org/licenses/>.  */
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/* crti.S puts a function prologue at the beginning of the .init and
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   .fini sections and defines global symbols for those addresses, so
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   they can be called as functions.  The symbols _init and _fini are
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   magic and cause the linker to emit DT_INIT and DT_FINI.  */
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#include <libc-symbols.h>
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#include <sysdep.h>
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#ifndef PREINIT_FUNCTION
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# define PREINIT_FUNCTION __gmon_start__
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#endif
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#ifndef PREINIT_FUNCTION_WEAK
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# define PREINIT_FUNCTION_WEAK 1
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#endif
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#if PREINIT_FUNCTION_WEAK
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	weak_extern (PREINIT_FUNCTION)
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#else
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	.hidden PREINIT_FUNCTION
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#endif
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/* If we have working .init_array support, we want to keep the .init
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   section empty (apart from the mandatory prologue/epilogue.  This
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   ensures that the default unwind conventions (return-pointer in b0,
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   frame state in ar.pfs, etc.)  will do the Right Thing.  To ensure
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   an empty .init section, we register gmon_initializer() via the
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   .init_array.
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    --davidm 02/10/29 */
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#if PREINIT_FUNCTION_WEAK
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/* This blob of assembly code is one simple C function:
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static void
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__attribute__ ((used))
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gmon_initializer (void)
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{
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  extern void weak_function __gmon_start__ (void);
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  if (__gmon_start__)
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    (*__gmon_start__)();
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}
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In a final executable, PLABEL32 relocations for function pointers are
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resolved at link time.  Typically, binutils/ld resolves __gmon_start__
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using an external shared library.  __gmon_start__ is always called if
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it is found at link time.  If __gmon_start__ is not found at runtime
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due to a library update, then the function pointer will point at a null
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function descriptor and calling it will cause a segmentation fault.
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So, we call __canonicalize_funcptr_for_compare to obtain the canonicalized
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address of __gmon_start__ and skip calling __gmon_start__ if it is zero.
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 */
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	.type __canonicalize_funcptr_for_compare,@function
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	.type $$dyncall,@function
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	.section .data.rel.ro,"aw",@progbits
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	.align 4
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.LC0:
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	.type __gmon_start__,@function
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	.word P%__gmon_start__
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	.text
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	.align 4
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	.type gmon_initializer,@function
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gmon_initializer:
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	.PROC
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	.CALLINFO FRAME=64,CALLS,SAVE_RP,ENTRY_GR=4
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	.ENTRY
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	stw %r2,-20(%r30)
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	stwm %r4,64(%r30)
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	stw %r3,-60(%r30)
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	addil LT'.LC0,%r19
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	ldw RT'.LC0(%r1),%r28
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	ldw 0(%r28),%r3
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	comib,= 0,%r3,1f
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	copy %r19,%r4
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	stw %r19,-32(%r30)
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	bl __canonicalize_funcptr_for_compare,%r2
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	copy %r3,%r26
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	comib,= 0,%r28,1f
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	copy %r4,%r19
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	copy %r3,%r22
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	.CALL ARGW0=GR
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	bl $$dyncall,%r31
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	copy %r31,%r2
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1:
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	ldw -84(%r30),%r2
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	ldw -60(%r30),%r3
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	bv %r0(%r2)
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	ldwm -64(%r30),%r4
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	.EXIT
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	.PROCEND
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	.size gmon_initializer, .-gmon_initializer
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# undef PREINIT_FUNCTION
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# define PREINIT_FUNCTION gmon_initializer
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#endif
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	.section .init_array, "aw"
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	.word P% PREINIT_FUNCTION
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/* _init prologue.  */
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	.section .init, "ax", %progbits
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	.align 4
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	.globl _init
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	.hidden	_init
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	.type _init,@function
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_init:
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	stw	%rp,-20(%sp)
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	stwm	%r4,64(%sp)
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	stw	%r19,-32(%sp)
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/* _fini prologue.  */
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        .section .fini,"ax",%progbits
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	.align 4
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	.globl _fini
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	.hidden	_fini
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	.type _fini,@function
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_fini:
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	stw	%rp,-20(%sp)
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	stwm	%r4,64(%sp)
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	stw	%r19,-32(%sp)
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	copy	%r19,%r4