1/* Special .init and .fini section support for IA64.
2 Copyright (C) 2000-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 In addition to the permissions in the GNU Lesser General Public
11 License, the Free Software Foundation gives you unlimited
12 permission to link the compiled version of this file with other
13 programs, and to distribute those programs without any restriction
14 coming from the use of this file. (The GNU Lesser General Public
15 License restrictions do apply in other respects; for example, they
16 cover modification of the file, and distribution when not linked
17 into another program.)
18
19 Note that people who make modified versions of this file are not
20 obligated to grant this special exception for their modified
21 versions; it is their choice whether to do so. The GNU Lesser
22 General Public License gives permission to release a modified
23 version without this exception; this exception also makes it
24 possible to release a modified version which carries forward this
25 exception.
26
27 The GNU C Library is distributed in the hope that it will be useful,
28 but WITHOUT ANY WARRANTY; without even the implied warranty of
29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 Lesser General Public License for more details.
31
32 You should have received a copy of the GNU Lesser General Public
33 License along with the GNU C Library. If not, see
34 <https://www.gnu.org/licenses/>. */
35
36/* crti.S puts a function prologue at the beginning of the .init and
37 .fini sections and defines global symbols for those addresses, so
38 they can be called as functions. The symbols _init and _fini are
39 magic and cause the linker to emit DT_INIT and DT_FINI. */
40
41#include <libc-symbols.h>
42#include <sysdep.h>
43#undef ret
44
45#ifndef PREINIT_FUNCTION
46# define PREINIT_FUNCTION __gmon_start__
47#endif
48
49#ifndef PREINIT_FUNCTION_WEAK
50# define PREINIT_FUNCTION_WEAK 1
51#endif
52
53#if PREINIT_FUNCTION_WEAK
54 weak_extern (PREINIT_FUNCTION)
55#else
56 .hidden PREINIT_FUNCTION
57#endif
58
59/* If we have working .init_array support, we want to keep the .init
60 section empty (apart from the mandatory prologue/epilogue. This
61 ensures that the default unwind conventions (return-pointer in b0,
62 frame state in ar.pfs, etc.) will do the Right Thing. To ensure
63 an empty .init section, we register gmon_initializer() via the
64 .init_array.
65
66 --davidm 02/10/29 */
67
68#if PREINIT_FUNCTION_WEAK
69/* This blob of assembly code is one simple C function:
70
71static void
72__attribute__ ((used))
73gmon_initializer (void)
74{
75 extern void weak_function __gmon_start__ (void);
76
77 if (__gmon_start__)
78 (*__gmon_start__)();
79}
80 */
81 .text
82 .align 64
83 .proc gmon_initializer#
84gmon_initializer:
85 .prologue 12, 32
86 .mmi
87 .save ar.pfs, r33
88 alloc r33 = ar.pfs, 0, 3, 0, 0
89 addl r14 = @ltoff(@fptr(PREINIT_FUNCTION#)), gp
90 .save rp, r32
91 mov r32 = b0
92 .mmi
93 mov r34 = r1
94 .body
95 ;;
96 ld8 r14 = [r14]
97 nop 0
98 ;;
99 .mib
100 cmp.eq p6, p7 = 0, r14
101 nop 0
102 (p6) br.cond.spnt .L1
103 ;;
104 .mib
105 nop 0
106 nop 0
107 br.call.sptk.many b0 = PREINIT_FUNCTION#
108 ;;
109 .mmi
110 mov r1 = r34
111 nop 0
112 nop 0
113.L1:
114 .mii
115 nop 0
116 mov ar.pfs = r33
117 nop 0
118 ;;
119 .mib
120 nop 0
121 mov b0 = r32
122 br.ret.sptk.many b0
123 .endp gmon_initializer#
124# undef PREINIT_FUNCTION
125# define PREINIT_FUNCTION gmon_initializer
126#endif
127 .section .init_array, "aw"
128 data8 @fptr(PREINIT_FUNCTION)
129
130 .section .init,"ax",@progbits
131 .global _init#
132 .hidden _init#
133 .proc _init#
134_init:
135 .prologue
136 .save ar.pfs, r34
137 alloc r34 = ar.pfs, 0, 3, 0, 0
138 .vframe r32
139 mov r32 = r12
140 .save rp, r33
141 mov r33 = b0
142 .body
143 adds r12 = -16, r12
144 ;; /* see gmon_initializer() above */
145 .endp _init#
146
147 .section .fini,"ax",@progbits
148 .global _fini#
149 .hidden _fini#
150 .proc _fini#
151_fini:
152 .prologue
153 .save ar.pfs, r34
154 alloc r34 = ar.pfs, 0, 3, 0, 0
155 .vframe r32
156 mov r32 = r12
157 .save rp, r33
158 mov r33 = b0
159 .body
160 adds r12 = -16, r12
161 ;;
162 .endp _fini#
163

source code of glibc/sysdeps/ia64/crti.S