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c053fa34 | 1 | /* Special .init and .fini section support for HPPA |
688903eb | 2 | Copyright (C) 2000-2018 Free Software Foundation, Inc. |
c053fa34 CD |
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 | <http://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 | ||
44 | #ifndef PREINIT_FUNCTION | |
45 | # define PREINIT_FUNCTION __gmon_start__ | |
46 | #endif | |
47 | ||
48 | #ifndef PREINIT_FUNCTION_WEAK | |
49 | # define PREINIT_FUNCTION_WEAK 1 | |
50 | #endif | |
51 | ||
b3f7fb12 JDA |
52 | #if PREINIT_FUNCTION_WEAK |
53 | weak_extern (PREINIT_FUNCTION) | |
54 | #else | |
55 | .hidden PREINIT_FUNCTION | |
56 | #endif | |
57 | ||
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 | ||
71 | static void | |
72 | __attribute__ ((used)) | |
73 | gmon_initializer (void) | |
74 | { | |
75 | extern void weak_function __gmon_start__ (void); | |
76 | ||
77 | if (__gmon_start__) | |
78 | (*__gmon_start__)(); | |
79 | } | |
80 | ||
81 | In a final executable, PLABEL32 relocations for function pointers are | |
82 | resolved at link time. Typically, binutils/ld resolves __gmon_start__ | |
83 | using an external shared library. __gmon_start__ is always called if | |
84 | it is found at link time. If __gmon_start__ is not found at runtime | |
85 | due to a library update, then the function pointer will point at a null | |
86 | function descriptor and calling it will cause a segmentation fault. | |
87 | So, we call __canonicalize_funcptr_for_compare to obtain the canonicalized | |
88 | address of __gmon_start__ and skip calling __gmon_start__ if it is zero. | |
89 | ||
90 | */ | |
91 | .type __canonicalize_funcptr_for_compare,@function | |
92 | .type $$dyncall,@function | |
93 | ||
94 | .section .data.rel.ro,"aw",@progbits | |
95 | .align 4 | |
96 | .LC0: | |
97 | .type __gmon_start__,@function | |
98 | .word P%__gmon_start__ | |
99 | ||
100 | .text | |
101 | .align 4 | |
102 | .type gmon_initializer,@function | |
103 | gmon_initializer: | |
104 | .PROC | |
105 | .CALLINFO FRAME=64,CALLS,SAVE_RP,ENTRY_GR=4 | |
106 | .ENTRY | |
107 | stw %r2,-20(%r30) | |
108 | stwm %r4,64(%r30) | |
109 | stw %r3,-60(%r30) | |
110 | addil LT'.LC0,%r19 | |
111 | ldw RT'.LC0(%r1),%r28 | |
112 | ldw 0(%r28),%r3 | |
113 | comib,= 0,%r3,1f | |
114 | copy %r19,%r4 | |
115 | stw %r19,-32(%r30) | |
116 | bl __canonicalize_funcptr_for_compare,%r2 | |
117 | copy %r3,%r26 | |
118 | comib,= 0,%r28,1f | |
119 | copy %r4,%r19 | |
120 | copy %r3,%r22 | |
121 | .CALL ARGW0=GR | |
122 | bl $$dyncall,%r31 | |
123 | copy %r31,%r2 | |
124 | 1: | |
125 | ldw -84(%r30),%r2 | |
126 | ldw -60(%r30),%r3 | |
127 | bv %r0(%r2) | |
128 | ldwm -64(%r30),%r4 | |
129 | .EXIT | |
130 | .PROCEND | |
131 | .size gmon_initializer, .-gmon_initializer | |
132 | ||
133 | # undef PREINIT_FUNCTION | |
134 | # define PREINIT_FUNCTION gmon_initializer | |
135 | #endif | |
136 | ||
137 | .section .init_array, "aw" | |
138 | .word P% PREINIT_FUNCTION | |
139 | ||
140 | ||
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141 | /* _init prologue. */ |
142 | .section .init, "ax", %progbits | |
143 | .align 4 | |
144 | .globl _init | |
67c05796 | 145 | .hidden _init |
c053fa34 CD |
146 | .type _init,@function |
147 | _init: | |
148 | stw %rp,-20(%sp) | |
149 | stwm %r4,64(%sp) | |
150 | stw %r19,-32(%sp) | |
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151 | |
152 | /* _fini prologue. */ | |
153 | .section .fini,"ax",%progbits | |
154 | .align 4 | |
155 | .globl _fini | |
67c05796 | 156 | .hidden _fini |
c053fa34 CD |
157 | .type _fini,@function |
158 | _fini: | |
159 | stw %rp,-20(%sp) | |
160 | stwm %r4,64(%sp) | |
161 | stw %r19,-32(%sp) | |
162 | copy %r19,%r4 |