1 /* Specialized bits of code needed to support construction and
2 destruction of file-scope objects in C++ code.
3 Copyright (C) 1991-2023 Free Software Foundation, Inc.
4 Contributed by Ron Guilmette (rfg@monkeys.com).
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 Under Section 7 of GPL version 3, you are granted additional
19 permissions described in the GCC Runtime Library Exception, version
20 3.1, as published by the Free Software Foundation.
21
22 You should have received a copy of the GNU General Public License and
23 a copy of the GCC Runtime Library Exception along with this program;
24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 <http://www.gnu.org/licenses/>. */
26
27 /* This file is a bit like libgcc2.c in that it is compiled
28 multiple times and yields multiple .o files.
29
30 This file is useful on target machines where the object file format
31 supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE). On
32 such systems, this file allows us to avoid running collect (or any
33 other such slow and painful kludge). Additionally, if the target
34 system supports a .init section, this file allows us to support the
35 linking of C++ code with a non-C++ main program.
36
37 Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
38 this file *will* make use of the .init section. If that symbol is
39 not defined however, then the .init section will not be used.
40
41 Currently, only ELF and COFF are supported. It is likely however that
42 ROSE could also be supported, if someone was willing to do the work to
43 make whatever (small?) adaptations are needed. (Some work may be
44 needed on the ROSE assembler and linker also.)
45
46 This file must be compiled with gcc. */
47
48 /* Target machine header files require this define. */
49 #define IN_LIBGCC2
50
51 /* FIXME: Including auto-host is incorrect, but until we have
52 identified the set of defines that need to go into auto-target.h,
53 this will have to do. */
54 #include "auto-host.h"
55 #undef caddr_t
56 #undef pid_t
57 #undef rlim_t
58 #undef ssize_t
59 #undef vfork
60 #include "tconfig.h"
61 #include "tsystem.h"
62 #include "coretypes.h"
63 #include "tm.h"
64 #include "libgcc_tm.h"
65 #include "unwind-dw2-fde.h"
66
67 #ifndef FORCE_CODE_SECTION_ALIGN
68 # define FORCE_CODE_SECTION_ALIGN
69 #endif
70
71 #ifndef CRT_CALL_STATIC_FUNCTION
72 # define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC) \
73 static void __attribute__((__used__)) \
74 call_ ## FUNC (void) \
75 { \
76 asm (SECTION_OP); \
77 FUNC (); \
78 FORCE_CODE_SECTION_ALIGN \
79 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); \
80 }
81 #endif
82
83 #if defined(TARGET_DL_ITERATE_PHDR) && \
84 (defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__))
85 #define BSD_DL_ITERATE_PHDR_AVAILABLE
86 #endif
87
88 #if defined(OBJECT_FORMAT_ELF) \
89 && !defined(OBJECT_FORMAT_FLAT) \
90 && defined(HAVE_LD_EH_FRAME_HDR) \
91 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
92 && defined(BSD_DL_ITERATE_PHDR_AVAILABLE)
93 #include <link.h>
94 # define USE_PT_GNU_EH_FRAME
95 #endif
96
97 #if defined(OBJECT_FORMAT_ELF) \
98 && !defined(OBJECT_FORMAT_FLAT) \
99 && defined(HAVE_LD_EH_FRAME_HDR) && defined(TARGET_DL_ITERATE_PHDR) \
100 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
101 && defined(__sun__) && defined(__svr4__)
102 #include <link.h>
103 # define USE_PT_GNU_EH_FRAME
104 #endif
105
106 #if defined(OBJECT_FORMAT_ELF) \
107 && !defined(OBJECT_FORMAT_FLAT) \
108 && defined(HAVE_LD_EH_FRAME_HDR) \
109 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
110 && defined(__GLIBC__) && __GLIBC__ >= 2
111 #include <link.h>
112 /* uClibc pretends to be glibc 2.2 and DT_CONFIG is defined in its link.h.
113 But it doesn't use PT_GNU_EH_FRAME ELF segment currently. */
114 # if !defined(__UCLIBC__) \
115 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
116 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
117 # define USE_PT_GNU_EH_FRAME
118 # endif
119 #endif
120
121 #if defined(OBJECT_FORMAT_ELF) \
122 && !defined(OBJECT_FORMAT_FLAT) \
123 && defined(HAVE_LD_EH_FRAME_HDR) \
124 && !defined(CRTSTUFFT_O) \
125 && defined(inhibit_libc) \
126 && (defined(__GLIBC__) || defined(__gnu_linux__) || defined(__GNU__))
127 /* On systems using glibc, an inhibit_libc build of libgcc is only
128 part of a bootstrap process. Build the same crt*.o as would be
129 built with headers present, so that it is not necessary to build
130 glibc more than once for the bootstrap to converge. */
131 # define USE_PT_GNU_EH_FRAME
132 #endif
133
134 #ifdef USE_EH_FRAME_REGISTRY_ALWAYS
135 # ifndef __LIBGCC_EH_FRAME_SECTION_NAME__
136 # error "Can't use explicit exception-frame-registration without __LIBGCC_EH_FRAME_SECTION_NAME__"
137 # endif
138 #endif
139 #if defined(__LIBGCC_EH_FRAME_SECTION_NAME__) && (!defined(USE_PT_GNU_EH_FRAME) || defined(USE_EH_FRAME_REGISTRY_ALWAYS))
140 # define USE_EH_FRAME_REGISTRY
141 #endif
142 #if defined(__LIBGCC_EH_FRAME_SECTION_NAME__) \
143 && __LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__
144 # define EH_FRAME_SECTION_CONST const
145 #else
146 # define EH_FRAME_SECTION_CONST
147 #endif
148
149 #if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \
150 && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP)
151 # define HIDDEN_DTOR_LIST_END
152 #endif
153
154 #if !defined(USE_TM_CLONE_REGISTRY) && defined(OBJECT_FORMAT_ELF)
155 # define USE_TM_CLONE_REGISTRY 1
156 #elif !defined(USE_TM_CLONE_REGISTRY)
157 # define USE_TM_CLONE_REGISTRY 0
158 #endif
159
160 /* We do not want to add the weak attribute to the declarations of these
161 routines in unwind-dw2-fde.h because that will cause the definition of
162 these symbols to be weak as well.
163
164 This exposes a core issue, how to handle creating weak references vs
165 how to create weak definitions. Either we have to have the definition
166 of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or
167 have a second declaration if we want a function's references to be weak,
168 but not its definition.
169
170 Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until
171 one thinks about scaling to larger problems -- i.e., the condition under
172 which TARGET_WEAK_ATTRIBUTE is active will eventually get far too
173 complicated.
174
175 So, we take an approach similar to #pragma weak -- we have a second
176 declaration for functions that we want to have weak references.
177
178 Neither way is particularly good. */
179
180 /* References to __register_frame_info and __deregister_frame_info should
181 be weak in this file if at all possible. */
182 extern void __register_frame_info (const void *, struct object *)
183 TARGET_ATTRIBUTE_WEAK;
184 extern void __register_frame_info_bases (const void *, struct object *,
185 void *, void *)
186 TARGET_ATTRIBUTE_WEAK;
187 extern void *__deregister_frame_info (const void *)
188 TARGET_ATTRIBUTE_WEAK;
189 extern void *__deregister_frame_info_bases (const void *)
190 TARGET_ATTRIBUTE_WEAK;
191 extern void __do_global_ctors_1 (void);
192
193 /* Likewise for transactional memory clone tables. */
194 extern void _ITM_registerTMCloneTable (void *, size_t) TARGET_ATTRIBUTE_WEAK;
195 extern void _ITM_deregisterTMCloneTable (void *) TARGET_ATTRIBUTE_WEAK;
196
197 #ifdef OBJECT_FORMAT_ELF
198
199 /* Declare a pointer to void function type. */
200 typedef void (*func_ptr) (void);
201 #define STATIC static
202
203 #else /* OBJECT_FORMAT_ELF */
204
205 #include "gbl-ctors.h"
206
207 #define STATIC
208
209 #endif /* OBJECT_FORMAT_ELF */
210
211 #ifdef CRT_BEGIN
212
213 /* NOTE: In order to be able to support SVR4 shared libraries, we arrange
214 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
215 __DTOR_END__ } per root executable and also one set of these symbols
216 per shared library. So in any given whole process image, we may have
217 multiple definitions of each of these symbols. In order to prevent
218 these definitions from conflicting with one another, and in order to
219 ensure that the proper lists are used for the initialization/finalization
220 of each individual shared library (respectively), we give these symbols
221 only internal (i.e. `static') linkage, and we also make it a point to
222 refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
223 symbol in crtbegin.o, where they are defined. */
224
225 /* No need for .ctors/.dtors section if linker can place them in
226 .init_array/.fini_array section. */
227 #ifndef USE_INITFINI_ARRAY
228 /* The -1 is a flag to __do_global_[cd]tors indicating that this table
229 does not start with a count of elements. */
230 #ifdef CTOR_LIST_BEGIN
231 CTOR_LIST_BEGIN;
232 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__)
233 /* Hack: force cc1 to switch to .data section early, so that assembling
234 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */
235 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
236 asm (__LIBGCC_CTORS_SECTION_ASM_OP__);
237 STATIC func_ptr __CTOR_LIST__[1]
238 __attribute__ ((__used__, aligned(__alignof__(func_ptr))))
239 = { (func_ptr) (-1) };
240 #else
241 STATIC func_ptr __CTOR_LIST__[1]
242 __attribute__ ((__used__, section(".ctors"), aligned(__alignof__(func_ptr))))
243 = { (func_ptr) (-1) };
244 #endif /* __CTOR_LIST__ alternatives */
245
246 #ifdef DTOR_LIST_BEGIN
247 DTOR_LIST_BEGIN;
248 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__)
249 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
250 STATIC func_ptr __DTOR_LIST__[1]
251 __attribute__ ((aligned(__alignof__(func_ptr))))
252 = { (func_ptr) (-1) };
253 #else
254 STATIC func_ptr __DTOR_LIST__[1]
255 __attribute__((section(".dtors"), aligned(__alignof__(func_ptr))))
256 = { (func_ptr) (-1) };
257 #endif /* __DTOR_LIST__ alternatives */
258 #endif /* USE_INITFINI_ARRAY */
259
260 #ifdef USE_EH_FRAME_REGISTRY
261 /* Stick a label at the beginning of the frame unwind info so we can register
262 and deregister it with the exception handling library code. */
263 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
264 __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__),
265 aligned(__alignof__ (void *))))
266 = { };
267 #endif /* USE_EH_FRAME_REGISTRY */
268
269 #if USE_TM_CLONE_REGISTRY
270 STATIC func_ptr __TMC_LIST__[]
271 __attribute__((used, section(".tm_clone_table"), aligned(__alignof__(void*))))
272 = { };
273 # ifdef HAVE_GAS_HIDDEN
274 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden")));
275 # endif
276
277 static inline void
278 deregister_tm_clones (void)
279 {
280 void (*fn) (void *);
281
282 #ifdef HAVE_GAS_HIDDEN
283 func_ptr *end = __TMC_END__;
284 // Do not optimize the comparison to false.
285 __asm ("" : "+g" (end));
286 if (__TMC_LIST__ == end)
287 return;
288 #else
289 if (__TMC_LIST__[0] == NULL)
290 return;
291 #endif
292
293 fn = _ITM_deregisterTMCloneTable;
294 __asm ("" : "+r" (fn));
295 if (fn)
296 fn (__TMC_LIST__);
297 }
298
299 static inline void
300 register_tm_clones (void)
301 {
302 void (*fn) (void *, size_t);
303 size_t size;
304
305 #ifdef HAVE_GAS_HIDDEN
306 func_ptr *end = __TMC_END__;
307 // Do not optimize the comparison to false.
308 __asm ("" : "+g" (end));
309 size = (end - __TMC_LIST__) / 2;
310 #else
311 for (size = 0; __TMC_LIST__[size * 2] != NULL; size++)
312 continue;
313 #endif
314 if (size == 0)
315 return;
316
317 fn = _ITM_registerTMCloneTable;
318 __asm ("" : "+r" (fn));
319 if (fn)
320 fn (__TMC_LIST__, size);
321 }
322 #endif /* USE_TM_CLONE_REGISTRY */
323
324 #if defined(__LIBGCC_INIT_SECTION_ASM_OP__) \
325 || defined(__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__)
326
327 #ifdef OBJECT_FORMAT_ELF
328
329 #if DEFAULT_USE_CXA_ATEXIT
330 /* Declare the __dso_handle variable. It should have a unique value
331 in every shared-object; in a main program its value is zero. The
332 object should in any case be protected. This means the instance
333 in one DSO or the main program is not used in another object. The
334 dynamic linker takes care of this.
335 If __cxa_atexit is not being used, __dso_handle will not be used and
336 doesn't need to be defined. */
337
338 #ifdef TARGET_LIBGCC_SDATA_SECTION
339 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
340 #endif
341 #ifdef HAVE_GAS_HIDDEN
342 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
343 #endif
344 #ifdef CRTSTUFFS_O
345 void *__dso_handle = &__dso_handle;
346 #else
347 void *__dso_handle = 0;
348 #endif
349 #endif /* DEFAULT_USE_CXA_ATEXIT */
350
351 /* The __cxa_finalize function may not be available so we use only a
352 weak declaration. */
353 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
354
355 /* Run all the global destructors on exit from the program. */
356
357 /* Some systems place the number of pointers in the first word of the
358 table. On SVR4 however, that word is -1. In all cases, the table is
359 null-terminated. On SVR4, we start from the beginning of the list and
360 invoke each per-compilation-unit destructor routine in order
361 until we find that null.
362
363 Note that this function MUST be static. There will be one of these
364 functions in each root executable and one in each shared library, but
365 although they all have the same code, each one is unique in that it
366 refers to one particular associated `__DTOR_LIST__' which belongs to the
367 same particular root executable or shared library file.
368
369 On some systems, this routine is run more than once from the .fini,
370 when exit is called recursively, so we arrange to remember where in
371 the list we left off processing, and we resume at that point,
372 should we be re-invoked.
373
374 This routine does not need to be run if none of the following clauses are
375 true, as it will not do anything, so can be removed. */
376 #if defined(CRTSTUFFS_O) || !defined(FINI_ARRAY_SECTION_ASM_OP) \
377 || USE_TM_CLONE_REGISTRY || defined(USE_EH_FRAME_REGISTRY)
378 static void __attribute__((used))
379 __do_global_dtors_aux (void)
380 {
381 static _Bool completed;
382
383 if (__builtin_expect (completed, 0))
384 return;
385
386 #if DEFAULT_USE_CXA_ATEXIT
387 #ifdef CRTSTUFFS_O
388 if (__cxa_finalize)
389 __cxa_finalize (__dso_handle);
390 #endif
391 #endif
392
393 #ifdef FINI_ARRAY_SECTION_ASM_OP
394 /* If we are using .fini_array then destructors will be run via that
395 mechanism. */
396 #elif defined(HIDDEN_DTOR_LIST_END)
397 {
398 /* Safer version that makes sure only .dtors function pointers are
399 called even if the static variable is maliciously changed. */
400 extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
401 static size_t dtor_idx;
402 const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
403 func_ptr *dtor_list;
404
405 __asm ("" : "=g" (dtor_list) : "0" (__DTOR_LIST__));
406 while (dtor_idx < max_idx)
407 dtor_list[++dtor_idx] ();
408 }
409 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
410 {
411 static func_ptr *p = __DTOR_LIST__ + 1;
412 func_ptr f;
413
414 while ((f = *p))
415 {
416 p++;
417 f ();
418 }
419 }
420 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
421
422 #if USE_TM_CLONE_REGISTRY
423 deregister_tm_clones ();
424 #endif /* USE_TM_CLONE_REGISTRY */
425
426 #ifdef USE_EH_FRAME_REGISTRY
427 #ifdef CRT_GET_RFIB_DATA
428 /* If we used the new __register_frame_info_bases interface,
429 make sure that we deregister from the same place. */
430 if (__deregister_frame_info_bases)
431 __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
432 #else
433 if (__deregister_frame_info)
434 __deregister_frame_info (__EH_FRAME_BEGIN__);
435 #endif
436 #endif
437
438 completed = 1;
439 }
440
441 /* Stick a call to __do_global_dtors_aux into the .fini section. */
442 #ifdef FINI_SECTION_ASM_OP
443 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
444 #elif defined (FINI_ARRAY_SECTION_ASM_OP)
445 #if defined(__FDPIC__)
446 __asm__("\t.equ\t__do_global_dtors_aux_alias, __do_global_dtors_aux\n");
447 extern char __do_global_dtors_aux_alias;
448 static void *__do_global_dtors_aux_fini_array_entry[]
449 __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(void *))))
450 = { &__do_global_dtors_aux_alias };
451 #else /* defined(__FDPIC__) */
452 static func_ptr __do_global_dtors_aux_fini_array_entry[]
453 __attribute__ ((__used__, section(".fini_array"),
454 aligned(__alignof__(func_ptr)))) = { __do_global_dtors_aux };
455 #endif /* defined(__FDPIC__) */
456 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */
457 static void __attribute__((used))
458 __do_global_dtors_aux_1 (void)
459 {
460 atexit (__do_global_dtors_aux);
461 }
462 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__,
463 __do_global_dtors_aux_1)
464 #endif
465 #endif /* defined(CRTSTUFFS_O) || !defined(FINI_ARRAY_SECTION_ASM_OP)
466 || USE_TM_CLONE_REGISTRY || defined(USE_EH_FRAME_REGISTRY) */
467
468 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY
469 /* Stick a call to __register_frame_info into the .init section. For some
470 reason calls with no arguments work more reliably in .init, so stick the
471 call in another function. */
472
473 static void __attribute__((used))
474 frame_dummy (void)
475 {
476 #ifdef USE_EH_FRAME_REGISTRY
477 static struct object object;
478 #ifdef CRT_GET_RFIB_DATA
479 void *tbase, *dbase;
480 tbase = 0;
481 CRT_GET_RFIB_DATA (dbase);
482 if (__register_frame_info_bases)
483 __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
484 #else
485 if (__register_frame_info)
486 __register_frame_info (__EH_FRAME_BEGIN__, &object);
487 #endif /* CRT_GET_RFIB_DATA */
488 #endif /* USE_EH_FRAME_REGISTRY */
489
490 #if USE_TM_CLONE_REGISTRY
491 register_tm_clones ();
492 #endif /* USE_TM_CLONE_REGISTRY */
493 }
494
495 #ifdef __LIBGCC_INIT_SECTION_ASM_OP__
496 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, frame_dummy)
497 #else /* defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
498 #if defined(__FDPIC__)
499 __asm__("\t.equ\t__frame_dummy_alias, frame_dummy\n");
500 extern char __frame_dummy_alias;
501 static void *__frame_dummy_init_array_entry[]
502 __attribute__ ((__used__, section(".init_array"), aligned(sizeof(void *))))
503 = { &__frame_dummy_alias };
504 #else /* defined(__FDPIC__) */
505 static func_ptr __frame_dummy_init_array_entry[]
506 __attribute__ ((__used__, section(".init_array"),
507 aligned(__alignof__(func_ptr)))) = { frame_dummy };
508 #endif /* defined(__FDPIC__) */
509 #endif /* !defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
510 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */
511
512 #else /* OBJECT_FORMAT_ELF */
513
514 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
515 and once in crtend.o). It must be declared static to avoid a link
516 error. Here, we define __do_global_ctors as an externally callable
517 function. It is externally callable so that __main can invoke it when
518 INVOKE__main is defined. This has the additional effect of forcing cc1
519 to switch to the .text section. */
520
521 static void __do_global_ctors_aux (void);
522 void
523 __do_global_ctors (void)
524 {
525 #ifdef INVOKE__main
526 /* If __main won't actually call __do_global_ctors then it doesn't matter
527 what's inside the function. The inside of __do_global_ctors_aux is
528 called automatically in that case. And the Alliant fx2800 linker
529 crashes on this reference. So prevent the crash. */
530 __do_global_ctors_aux ();
531 #endif
532 }
533
534 asm (__LIBGCC_INIT_SECTION_ASM_OP__); /* cc1 doesn't know that we are switching! */
535
536 /* A routine to invoke all of the global constructors upon entry to the
537 program. We put this into the .init section (for systems that have
538 such a thing) so that we can properly perform the construction of
539 file-scope static-storage C++ objects within shared libraries. */
540
541 static void __attribute__((used))
542 __do_global_ctors_aux (void) /* prologue goes in .init section */
543 {
544 FORCE_CODE_SECTION_ALIGN /* explicit align before switch to .text */
545 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); /* don't put epilogue and body in .init */
546 DO_GLOBAL_CTORS_BODY;
547 atexit (__do_global_dtors);
548 }
549
550 #endif /* OBJECT_FORMAT_ELF */
551
552 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
553
554 extern void __do_global_dtors (void);
555
556 /* This case is used by the Irix 6 port, which supports named sections but
557 not an SVR4-style .fini section. __do_global_dtors can be non-static
558 in this case because we protect it with -hidden_symbol. */
559
560 void
561 __do_global_dtors (void)
562 {
563 func_ptr *p, f;
564 for (p = __DTOR_LIST__ + 1; (f = *p); p++)
565 f ();
566
567 #if USE_TM_CLONE_REGISTRY
568 deregister_tm_clones ();
569 #endif /* USE_TM_CLONE_REGISTRY */
570
571 #ifdef USE_EH_FRAME_REGISTRY
572 if (__deregister_frame_info)
573 __deregister_frame_info (__EH_FRAME_BEGIN__);
574 #endif
575 }
576
577 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY
578 /* A helper function for __do_global_ctors, which is in crtend.o. Here
579 in crtbegin.o, we can reference a couple of symbols not visible there.
580 Plus, since we're before libgcc.a, we have no problems referencing
581 functions from there. */
582 void
583 __do_global_ctors_1(void)
584 {
585 #ifdef USE_EH_FRAME_REGISTRY
586 static struct object object;
587 if (__register_frame_info)
588 __register_frame_info (__EH_FRAME_BEGIN__, &object);
589 #endif
590
591 #if USE_TM_CLONE_REGISTRY
592 register_tm_clones ();
593 #endif /* USE_TM_CLONE_REGISTRY */
594 }
595 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */
596
597 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
598 #error "What are you doing with crtstuff.c, then?"
599 #endif
600
601 #elif defined(CRT_END) /* ! CRT_BEGIN */
602
603 /* No need for .ctors/.dtors section if linker can place them in
604 .init_array/.fini_array section. */
605 #ifndef USE_INITFINI_ARRAY
606 /* Put a word containing zero at the end of each of our two lists of function
607 addresses. Note that the words defined here go into the .ctors and .dtors
608 sections of the crtend.o file, and since that file is always linked in
609 last, these words naturally end up at the very ends of the two lists
610 contained in these two sections. */
611
612 #ifdef CTOR_LIST_END
613 CTOR_LIST_END;
614 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__)
615 /* Hack: force cc1 to switch to .data section early, so that assembling
616 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */
617 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
618 asm (__LIBGCC_CTORS_SECTION_ASM_OP__);
619 STATIC func_ptr __CTOR_END__[1]
620 __attribute__((aligned(__alignof__(func_ptr))))
621 = { (func_ptr) 0 };
622 #else
623 STATIC func_ptr __CTOR_END__[1]
624 __attribute__((section(".ctors"), aligned(__alignof__(func_ptr))))
625 = { (func_ptr) 0 };
626 #endif
627
628 #ifdef DTOR_LIST_END
629 DTOR_LIST_END;
630 #elif defined(HIDDEN_DTOR_LIST_END)
631 #ifdef __LIBGCC_DTORS_SECTION_ASM_OP__
632 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
633 #endif
634 func_ptr __DTOR_END__[1]
635 __attribute__ ((used,
636 #ifndef __LIBGCC_DTORS_SECTION_ASM_OP__
637 section(".dtors"),
638 #endif
639 aligned(__alignof__(func_ptr)), visibility ("hidden")))
640 = { (func_ptr) 0 };
641 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__)
642 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
643 STATIC func_ptr __DTOR_END__[1]
644 __attribute__ ((used, aligned(__alignof__(func_ptr))))
645 = { (func_ptr) 0 };
646 #else
647 STATIC func_ptr __DTOR_END__[1]
648 __attribute__((used, section(".dtors"), aligned(__alignof__(func_ptr))))
649 = { (func_ptr) 0 };
650 #endif
651 #endif /* USE_INITFINI_ARRAY */
652
653 #ifdef __LIBGCC_EH_FRAME_SECTION_NAME__
654 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
655 this would be the 'length' field in a real FDE. */
656 # if __INT_MAX__ == 2147483647
657 typedef int int32;
658 # elif __LONG_MAX__ == 2147483647
659 typedef long int32;
660 # elif __SHRT_MAX__ == 2147483647
661 typedef short int32;
662 # else
663 # error "Missing a 4 byte integer"
664 # endif
665 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
666 __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__),
667 aligned(__alignof__(int32))))
668 = { 0 };
669 #endif /* __LIBGCC_EH_FRAME_SECTION_NAME__ */
670
671 #if USE_TM_CLONE_REGISTRY
672 # ifndef HAVE_GAS_HIDDEN
673 static
674 # endif
675 func_ptr __TMC_END__[]
676 __attribute__((used, section(".tm_clone_table"),
677 aligned(__alignof__(void *))))
678 # ifdef HAVE_GAS_HIDDEN
679 __attribute__((__visibility__ ("hidden"))) = { };
680 # else
681 = { 0, 0 };
682 # endif
683 #endif /* USE_TM_CLONE_REGISTRY */
684
685 #ifdef __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__
686
687 /* If we are using .init_array, there is nothing to do. */
688
689 #elif defined(__LIBGCC_INIT_SECTION_ASM_OP__)
690
691 #ifdef OBJECT_FORMAT_ELF
692 static void __attribute__((used))
693 __do_global_ctors_aux (void)
694 {
695 func_ptr *p;
696 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
697 (*p) ();
698 }
699
700 /* Stick a call to __do_global_ctors_aux into the .init section. */
701 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, __do_global_ctors_aux)
702 #else /* OBJECT_FORMAT_ELF */
703
704 /* Stick the real initialization code, followed by a normal sort of
705 function epilogue at the very end of the .init section for this
706 entire root executable file or for this entire shared library file.
707
708 Note that we use some tricks here to get *just* the body and just
709 a function epilogue (but no function prologue) into the .init
710 section of the crtend.o file. Specifically, we switch to the .text
711 section, start to define a function, and then we switch to the .init
712 section just before the body code.
713
714 Earlier on, we put the corresponding function prologue into the .init
715 section of the crtbegin.o file (which will be linked in first).
716
717 Note that we want to invoke all constructors for C++ file-scope static-
718 storage objects AFTER any other possible initialization actions which
719 may be performed by the code in the .init section contributions made by
720 other libraries, etc. That's because those other initializations may
721 include setup operations for very primitive things (e.g. initializing
722 the state of the floating-point coprocessor, etc.) which should be done
723 before we start to execute any of the user's code. */
724
725 static void
726 __do_global_ctors_aux (void) /* prologue goes in .text section */
727 {
728 asm (__LIBGCC_INIT_SECTION_ASM_OP__);
729 DO_GLOBAL_CTORS_BODY;
730 atexit (__do_global_dtors);
731 } /* epilogue and body go in .init section */
732
733 FORCE_CODE_SECTION_ALIGN
734 asm (__LIBGCC_TEXT_SECTION_ASM_OP__);
735
736 #endif /* OBJECT_FORMAT_ELF */
737
738 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
739
740 extern void __do_global_ctors (void);
741
742 /* This case is used by the Irix 6 port, which supports named sections but
743 not an SVR4-style .init section. __do_global_ctors can be non-static
744 in this case because we protect it with -hidden_symbol. */
745 void
746 __do_global_ctors (void)
747 {
748 func_ptr *p;
749 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY
750 __do_global_ctors_1();
751 #endif
752 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
753 (*p) ();
754 }
755
756 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
757 #error "What are you doing with crtstuff.c, then?"
758 #endif
759
760 #else /* ! CRT_BEGIN && ! CRT_END */
761 #error "One of CRT_BEGIN or CRT_END must be defined."
762 #endif