crtbegin.c revision 360784 
1//===-- crtbegin.c - Start of constructors and destructors ----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <stddef.h>
10
11__attribute__((visibility("hidden"))) void *__dso_handle = &__dso_handle;
12
13#ifdef EH_USE_FRAME_REGISTRY
14__extension__ static void *__EH_FRAME_LIST__[]
15    __attribute__((section(".eh_frame"), aligned(sizeof(void *)))) = {};
16
17extern void __register_frame_info(const void *, void *) __attribute__((weak));
18extern void *__deregister_frame_info(const void *) __attribute__((weak));
19#endif
20
21#ifndef CRT_HAS_INITFINI_ARRAY
22typedef void (*fp)(void);
23
24static fp __CTOR_LIST__[]
25    __attribute__((section(".ctors"), aligned(sizeof(fp)))) = {(fp)-1};
26extern fp __CTOR_LIST_END__[];
27#endif
28
29extern void __cxa_finalize(void *) __attribute__((weak));
30
31static void __attribute__((used)) __do_init() {
32  static _Bool __initialized;
33  if (__builtin_expect(__initialized, 0))
34    return;
35  __initialized = 1;
36
37#ifdef EH_USE_FRAME_REGISTRY
38  static struct { void *p[8]; } __object;
39  if (__register_frame_info)
40    __register_frame_info(__EH_FRAME_LIST__, &__object);
41#endif
42#ifndef CRT_HAS_INITFINI_ARRAY
43  const size_t n = __CTOR_LIST_END__ - __CTOR_LIST__ - 1;
44  for (size_t i = n; i >= 1; i--) __CTOR_LIST__[i]();
45#endif
46}
47
48#ifdef CRT_HAS_INITFINI_ARRAY
49__attribute__((section(".init_array"),
50               used)) static void (*__init)(void) = __do_init;
51#elif defined(__i386__) || defined(__x86_64__)
52__asm__(".pushsection .init,\"ax\",@progbits\n\t"
53    "call " __USER_LABEL_PREFIX__ "__do_init\n\t"
54    ".popsection");
55#elif defined(__arm__) || defined(__aarch64__)
56__asm__(".pushsection .init,\"ax\",%progbits\n\t"
57    "bl " __USER_LABEL_PREFIX__ "__do_init\n\t"
58    ".popsection");
59#elif defined(__powerpc__) || defined(__powerpc64__)
60__asm__(".pushsection .init,\"ax\",@progbits\n\t"
61    "bl " __USER_LABEL_PREFIX__ "__do_init\n\t"
62    "nop\n\t"
63    ".popsection");
64#elif defined(__sparc__)
65__asm__(".pushsection .init,\"ax\",@progbits\n\t"
66    "call " __USER_LABEL_PREFIX__ "__do_init\n\t"
67    ".popsection");
68#else
69#error "crtbegin without .init_fini array unimplemented for this architecture"
70#endif // CRT_HAS_INITFINI_ARRAY
71
72#ifndef CRT_HAS_INITFINI_ARRAY
73static fp __DTOR_LIST__[]
74    __attribute__((section(".dtors"), aligned(sizeof(fp)))) = {(fp)-1};
75extern fp __DTOR_LIST_END__[];
76#endif
77
78static void __attribute__((used)) __do_fini() {
79  static _Bool __finalized;
80  if (__builtin_expect(__finalized, 0))
81    return;
82  __finalized = 1;
83
84  if (__cxa_finalize)
85    __cxa_finalize(__dso_handle);
86
87#ifndef CRT_HAS_INITFINI_ARRAY
88  const size_t n = __DTOR_LIST_END__ - __DTOR_LIST__ - 1;
89  for (size_t i = 1; i <= n; i++) __DTOR_LIST__[i]();
90#endif
91#ifdef EH_USE_FRAME_REGISTRY
92  if (__deregister_frame_info)
93    __deregister_frame_info(__EH_FRAME_LIST__);
94#endif
95}
96
97#ifdef CRT_HAS_INITFINI_ARRAY
98__attribute__((section(".fini_array"),
99               used)) static void (*__fini)(void) = __do_fini;
100#elif defined(__i386__) || defined(__x86_64__)
101__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
102    "call " __USER_LABEL_PREFIX__ "__do_fini\n\t"
103    ".popsection");
104#elif defined(__arm__) || defined(__aarch64__)
105__asm__(".pushsection .fini,\"ax\",%progbits\n\t"
106    "bl " __USER_LABEL_PREFIX__ "__do_fini\n\t"
107    ".popsection");
108#elif defined(__powerpc__) || defined(__powerpc64__)
109__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
110    "bl " __USER_LABEL_PREFIX__ "__do_fini\n\t"
111    "nop\n\t"
112    ".popsection");
113#elif defined(__sparc__)
114__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
115    "call " __USER_LABEL_PREFIX__ "__do_fini\n\t"
116    ".popsection");
117#else
118#error "crtbegin without .init_fini array unimplemented for this architecture"
119#endif  // CRT_HAS_INIT_FINI_ARRAY
120