xref: /netbsd-src/external/gpl3/gcc/dist/libgcc/crtstuff.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /* Specialized bits of code needed to support construction and
2    destruction of file-scope objects in C++ code.
3    Copyright (C) 1991-2013 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 pid_t
56 #undef rlim_t
57 #undef ssize_t
58 #undef vfork
59 #include "tconfig.h"
60 #include "tsystem.h"
61 #include "coretypes.h"
62 #include "tm.h"
63 #include "libgcc_tm.h"
64 #include "unwind-dw2-fde.h"
65 
66 #ifndef FORCE_CODE_SECTION_ALIGN
67 # define FORCE_CODE_SECTION_ALIGN
68 #endif
69 
70 #ifndef CRT_CALL_STATIC_FUNCTION
71 # define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)	\
72 static void __attribute__((__used__))			\
73 call_ ## FUNC (void)					\
74 {							\
75   asm (SECTION_OP);					\
76   FUNC ();						\
77   FORCE_CODE_SECTION_ALIGN				\
78   asm (TEXT_SECTION_ASM_OP);				\
79 }
80 #endif
81 
82 #if defined(OBJECT_FORMAT_ELF) \
83     && !defined(OBJECT_FORMAT_FLAT) \
84     && defined(HAVE_LD_EH_FRAME_HDR) \
85     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
86     && defined(__FreeBSD__) && __FreeBSD__ >= 7
87 #include <link.h>
88 # define USE_PT_GNU_EH_FRAME
89 #endif
90 
91 #if defined(OBJECT_FORMAT_ELF) \
92     && !defined(OBJECT_FORMAT_FLAT) \
93     && defined(HAVE_LD_EH_FRAME_HDR) && defined(TARGET_DL_ITERATE_PHDR) \
94     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
95     && defined(__sun__) && defined(__svr4__)
96 #include <link.h>
97 # define USE_PT_GNU_EH_FRAME
98 #endif
99 
100 #if defined(OBJECT_FORMAT_ELF) \
101     && !defined(OBJECT_FORMAT_FLAT) \
102     && defined(HAVE_LD_EH_FRAME_HDR) \
103     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
104     && defined(__GLIBC__) && __GLIBC__ >= 2
105 #include <link.h>
106 /* uClibc pretends to be glibc 2.2 and DT_CONFIG is defined in its link.h.
107    But it doesn't use PT_GNU_EH_FRAME ELF segment currently.  */
108 # if !defined(__UCLIBC__) \
109      && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
110      || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
111 #  define USE_PT_GNU_EH_FRAME
112 # endif
113 #endif
114 
115 #if defined(OBJECT_FORMAT_ELF) \
116     && !defined(OBJECT_FORMAT_FLAT) \
117     && defined(HAVE_LD_EH_FRAME_HDR) \
118     && !defined(CRTSTUFFT_O) \
119     && defined(inhibit_libc) \
120     && (defined(__GLIBC__) || defined(__gnu_linux__) || defined(__GNU__))
121 /* On systems using glibc, an inhibit_libc build of libgcc is only
122    part of a bootstrap process.  Build the same crt*.o as would be
123    built with headers present, so that it is not necessary to build
124    glibc more than once for the bootstrap to converge.  */
125 # define USE_PT_GNU_EH_FRAME
126 #endif
127 
128 #if defined(EH_FRAME_SECTION_NAME) && !defined(USE_PT_GNU_EH_FRAME)
129 # define USE_EH_FRAME_REGISTRY
130 #endif
131 #if defined(EH_FRAME_SECTION_NAME) && EH_TABLES_CAN_BE_READ_ONLY
132 # define EH_FRAME_SECTION_CONST const
133 #else
134 # define EH_FRAME_SECTION_CONST
135 #endif
136 
137 #if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \
138     && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP)
139 # define HIDDEN_DTOR_LIST_END
140 #endif
141 
142 #if !defined(USE_TM_CLONE_REGISTRY) && defined(OBJECT_FORMAT_ELF)
143 # define USE_TM_CLONE_REGISTRY 1
144 #endif
145 
146 /* We do not want to add the weak attribute to the declarations of these
147    routines in unwind-dw2-fde.h because that will cause the definition of
148    these symbols to be weak as well.
149 
150    This exposes a core issue, how to handle creating weak references vs
151    how to create weak definitions.  Either we have to have the definition
152    of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or
153    have a second declaration if we want a function's references to be weak,
154    but not its definition.
155 
156    Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until
157    one thinks about scaling to larger problems -- i.e., the condition under
158    which TARGET_WEAK_ATTRIBUTE is active will eventually get far too
159    complicated.
160 
161    So, we take an approach similar to #pragma weak -- we have a second
162    declaration for functions that we want to have weak references.
163 
164    Neither way is particularly good.  */
165 
166 /* References to __register_frame_info and __deregister_frame_info should
167    be weak in this file if at all possible.  */
168 extern void __register_frame_info (const void *, struct object *)
169 				  TARGET_ATTRIBUTE_WEAK;
170 extern void __register_frame_info_bases (const void *, struct object *,
171 					 void *, void *)
172 				  TARGET_ATTRIBUTE_WEAK;
173 extern void *__deregister_frame_info (const void *)
174 				     TARGET_ATTRIBUTE_WEAK;
175 extern void *__deregister_frame_info_bases (const void *)
176 				     TARGET_ATTRIBUTE_WEAK;
177 extern void __do_global_ctors_1 (void);
178 
179 /* Likewise for _Jv_RegisterClasses.  */
180 extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK;
181 
182 /* Likewise for transactional memory clone tables.  */
183 extern void _ITM_registerTMCloneTable (void *, size_t) TARGET_ATTRIBUTE_WEAK;
184 extern void _ITM_deregisterTMCloneTable (void *) TARGET_ATTRIBUTE_WEAK;
185 
186 #ifdef OBJECT_FORMAT_ELF
187 
188 /*  Declare a pointer to void function type.  */
189 typedef void (*func_ptr) (void);
190 #define STATIC static
191 
192 #else  /* OBJECT_FORMAT_ELF */
193 
194 #include "gbl-ctors.h"
195 
196 #define STATIC
197 
198 #endif /* OBJECT_FORMAT_ELF */
199 
200 #ifdef CRT_BEGIN
201 
202 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
203    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
204    __DTOR_END__ } per root executable and also one set of these symbols
205    per shared library.  So in any given whole process image, we may have
206    multiple definitions of each of these symbols.  In order to prevent
207    these definitions from conflicting with one another, and in order to
208    ensure that the proper lists are used for the initialization/finalization
209    of each individual shared library (respectively), we give these symbols
210    only internal (i.e. `static') linkage, and we also make it a point to
211    refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
212    symbol in crtbegin.o, where they are defined.  */
213 
214 /* No need for .ctors/.dtors section if linker can place them in
215    .init_array/.fini_array section.  */
216 #ifndef USE_INITFINI_ARRAY
217 /* The -1 is a flag to __do_global_[cd]tors indicating that this table
218    does not start with a count of elements.  */
219 #ifdef CTOR_LIST_BEGIN
220 CTOR_LIST_BEGIN;
221 #elif defined(CTORS_SECTION_ASM_OP)
222 /* Hack: force cc1 to switch to .data section early, so that assembling
223    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
224 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
225 asm (CTORS_SECTION_ASM_OP);
226 STATIC func_ptr __CTOR_LIST__[1]
227   __attribute__ ((__used__, aligned(sizeof(func_ptr))))
228   = { (func_ptr) (-1) };
229 #else
230 STATIC func_ptr __CTOR_LIST__[1]
231   __attribute__ ((__used__, section(".ctors"), aligned(sizeof(func_ptr))))
232   = { (func_ptr) (-1) };
233 #endif /* __CTOR_LIST__ alternatives */
234 
235 #ifdef DTOR_LIST_BEGIN
236 DTOR_LIST_BEGIN;
237 #elif defined(DTORS_SECTION_ASM_OP)
238 asm (DTORS_SECTION_ASM_OP);
239 STATIC func_ptr __DTOR_LIST__[1]
240   __attribute__ ((aligned(sizeof(func_ptr))))
241   = { (func_ptr) (-1) };
242 #else
243 STATIC func_ptr __DTOR_LIST__[1]
244   __attribute__((section(".dtors"), aligned(sizeof(func_ptr))))
245   = { (func_ptr) (-1) };
246 #endif /* __DTOR_LIST__ alternatives */
247 #endif /* USE_INITFINI_ARRAY */
248 
249 #ifdef USE_EH_FRAME_REGISTRY
250 /* Stick a label at the beginning of the frame unwind info so we can register
251    and deregister it with the exception handling library code.  */
252 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
253      __attribute__((section(EH_FRAME_SECTION_NAME), aligned(4)))
254      = { };
255 #endif /* USE_EH_FRAME_REGISTRY */
256 
257 #ifdef JCR_SECTION_NAME
258 /* Stick a label at the beginning of the java class registration info
259    so we can register them properly.  */
260 STATIC void *__JCR_LIST__[]
261   __attribute__ ((used, section(JCR_SECTION_NAME), aligned(sizeof(void*))))
262   = { };
263 #endif /* JCR_SECTION_NAME */
264 
265 #if USE_TM_CLONE_REGISTRY
266 STATIC func_ptr __TMC_LIST__[]
267   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void*))))
268   = { };
269 # ifdef HAVE_GAS_HIDDEN
270 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden")));
271 # endif
272 
273 static inline void
274 deregister_tm_clones (void)
275 {
276   void (*fn) (void *);
277 
278 #ifdef HAVE_GAS_HIDDEN
279   if (__TMC_END__ - __TMC_LIST__ == 0)
280     return;
281 #else
282   if (__TMC_LIST__[0] == NULL)
283     return;
284 #endif
285 
286   fn = _ITM_deregisterTMCloneTable;
287   __asm ("" : "+r" (fn));
288   if (fn)
289     fn (__TMC_LIST__);
290 }
291 
292 static inline void
293 register_tm_clones (void)
294 {
295   void (*fn) (void *, size_t);
296   size_t size;
297 
298 #ifdef HAVE_GAS_HIDDEN
299   size = (__TMC_END__ - __TMC_LIST__) / 2;
300 #else
301   for (size = 0; __TMC_LIST__[size * 2] != NULL; size++)
302     continue;
303 #endif
304   if (size == 0)
305     return;
306 
307   fn = _ITM_registerTMCloneTable;
308   __asm ("" : "+r" (fn));
309   if (fn)
310     fn (__TMC_LIST__, size);
311 }
312 #endif /* USE_TM_CLONE_REGISTRY */
313 
314 #if defined(INIT_SECTION_ASM_OP) || defined(INIT_ARRAY_SECTION_ASM_OP)
315 
316 #ifdef OBJECT_FORMAT_ELF
317 
318 /* Declare the __dso_handle variable.  It should have a unique value
319    in every shared-object; in a main program its value is zero.  The
320    object should in any case be protected.  This means the instance
321    in one DSO or the main program is not used in another object.  The
322    dynamic linker takes care of this.  */
323 
324 #ifdef TARGET_LIBGCC_SDATA_SECTION
325 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
326 #endif
327 #ifdef HAVE_GAS_HIDDEN
328 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
329 #endif
330 #ifdef CRTSTUFFS_O
331 void *__dso_handle = &__dso_handle;
332 #else
333 void *__dso_handle = 0;
334 #endif
335 
336 /* The __cxa_finalize function may not be available so we use only a
337    weak declaration.  */
338 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
339 
340 /* Run all the global destructors on exit from the program.  */
341 
342 /* Some systems place the number of pointers in the first word of the
343    table.  On SVR4 however, that word is -1.  In all cases, the table is
344    null-terminated.  On SVR4, we start from the beginning of the list and
345    invoke each per-compilation-unit destructor routine in order
346    until we find that null.
347 
348    Note that this function MUST be static.  There will be one of these
349    functions in each root executable and one in each shared library, but
350    although they all have the same code, each one is unique in that it
351    refers to one particular associated `__DTOR_LIST__' which belongs to the
352    same particular root executable or shared library file.
353 
354    On some systems, this routine is run more than once from the .fini,
355    when exit is called recursively, so we arrange to remember where in
356    the list we left off processing, and we resume at that point,
357    should we be re-invoked.  */
358 
359 static void __attribute__((used))
360 __do_global_dtors_aux (void)
361 {
362   static _Bool completed;
363 
364   if (__builtin_expect (completed, 0))
365     return;
366 
367 #ifdef CRTSTUFFS_O
368   if (__cxa_finalize)
369     __cxa_finalize (__dso_handle);
370 #endif
371 
372 #ifdef FINI_ARRAY_SECTION_ASM_OP
373   /* If we are using .fini_array then destructors will be run via that
374      mechanism.  */
375 #elif defined(HIDDEN_DTOR_LIST_END)
376   {
377     /* Safer version that makes sure only .dtors function pointers are
378        called even if the static variable is maliciously changed.  */
379     extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
380     static size_t dtor_idx;
381     const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
382     func_ptr f;
383 
384     while (dtor_idx < max_idx)
385       {
386 	f = __DTOR_LIST__[++dtor_idx];
387 	f ();
388       }
389   }
390 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
391   {
392     static func_ptr *p = __DTOR_LIST__ + 1;
393     func_ptr f;
394 
395     while ((f = *p))
396       {
397 	p++;
398 	f ();
399       }
400   }
401 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
402 
403 #if USE_TM_CLONE_REGISTRY
404   deregister_tm_clones ();
405 #endif /* USE_TM_CLONE_REGISTRY */
406 
407 #ifdef USE_EH_FRAME_REGISTRY
408 #ifdef CRT_GET_RFIB_DATA
409   /* If we used the new __register_frame_info_bases interface,
410      make sure that we deregister from the same place.  */
411   if (__deregister_frame_info_bases)
412     __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
413 #else
414   if (__deregister_frame_info)
415     __deregister_frame_info (__EH_FRAME_BEGIN__);
416 #endif
417 #endif
418 
419   completed = 1;
420 }
421 
422 /* Stick a call to __do_global_dtors_aux into the .fini section.  */
423 #ifdef FINI_SECTION_ASM_OP
424 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
425 #elif defined (FINI_ARRAY_SECTION_ASM_OP)
426 static func_ptr __do_global_dtors_aux_fini_array_entry[]
427   __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(func_ptr))))
428   = { __do_global_dtors_aux };
429 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */
430 static void __attribute__((used))
431 __do_global_dtors_aux_1 (void)
432 {
433   atexit (__do_global_dtors_aux);
434 }
435 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_dtors_aux_1)
436 #endif
437 
438 #if defined(USE_EH_FRAME_REGISTRY) \
439     || defined(JCR_SECTION_NAME) \
440     || defined(USE_TM_CLONE_REGISTRY)
441 /* Stick a call to __register_frame_info into the .init section.  For some
442    reason calls with no arguments work more reliably in .init, so stick the
443    call in another function.  */
444 
445 static void __attribute__((used))
446 frame_dummy (void)
447 {
448 #ifdef USE_EH_FRAME_REGISTRY
449   static struct object object;
450 #ifdef CRT_GET_RFIB_DATA
451   void *tbase, *dbase;
452   tbase = 0;
453   CRT_GET_RFIB_DATA (dbase);
454   if (__register_frame_info_bases)
455     __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
456 #else
457   if (__register_frame_info)
458     __register_frame_info (__EH_FRAME_BEGIN__, &object);
459 #endif /* CRT_GET_RFIB_DATA */
460 #endif /* USE_EH_FRAME_REGISTRY */
461 
462 #ifdef JCR_SECTION_NAME
463   if (__JCR_LIST__[0])
464     {
465       void (*register_classes) (void *) = _Jv_RegisterClasses;
466       __asm ("" : "+r" (register_classes));
467       if (register_classes)
468 	register_classes (__JCR_LIST__);
469     }
470 #endif /* JCR_SECTION_NAME */
471 
472 #if USE_TM_CLONE_REGISTRY
473   register_tm_clones ();
474 #endif /* USE_TM_CLONE_REGISTRY */
475 }
476 
477 #ifdef INIT_SECTION_ASM_OP
478 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy)
479 #else /* defined(INIT_SECTION_ASM_OP) */
480 static func_ptr __frame_dummy_init_array_entry[]
481   __attribute__ ((__used__, section(".init_array"), aligned(sizeof(func_ptr))))
482   = { frame_dummy };
483 #endif /* !defined(INIT_SECTION_ASM_OP) */
484 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME || USE_TM_CLONE_REGISTRY */
485 
486 #else  /* OBJECT_FORMAT_ELF */
487 
488 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
489    and once in crtend.o).  It must be declared static to avoid a link
490    error.  Here, we define __do_global_ctors as an externally callable
491    function.  It is externally callable so that __main can invoke it when
492    INVOKE__main is defined.  This has the additional effect of forcing cc1
493    to switch to the .text section.  */
494 
495 static void __do_global_ctors_aux (void);
496 void
497 __do_global_ctors (void)
498 {
499 #ifdef INVOKE__main
500   /* If __main won't actually call __do_global_ctors then it doesn't matter
501      what's inside the function.  The inside of __do_global_ctors_aux is
502      called automatically in that case.  And the Alliant fx2800 linker
503      crashes on this reference.  So prevent the crash.  */
504   __do_global_ctors_aux ();
505 #endif
506 }
507 
508 asm (INIT_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */
509 
510 /* A routine to invoke all of the global constructors upon entry to the
511    program.  We put this into the .init section (for systems that have
512    such a thing) so that we can properly perform the construction of
513    file-scope static-storage C++ objects within shared libraries.  */
514 
515 static void __attribute__((used))
516 __do_global_ctors_aux (void)	/* prologue goes in .init section */
517 {
518   FORCE_CODE_SECTION_ALIGN	/* explicit align before switch to .text */
519   asm (TEXT_SECTION_ASM_OP);	/* don't put epilogue and body in .init */
520   DO_GLOBAL_CTORS_BODY;
521   atexit (__do_global_dtors);
522 }
523 
524 #endif /* OBJECT_FORMAT_ELF */
525 
526 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
527 
528 extern void __do_global_dtors (void);
529 
530 /* This case is used by the Irix 6 port, which supports named sections but
531    not an SVR4-style .fini section.  __do_global_dtors can be non-static
532    in this case because we protect it with -hidden_symbol.  */
533 
534 void
535 __do_global_dtors (void)
536 {
537   func_ptr *p, f;
538   for (p = __DTOR_LIST__ + 1; (f = *p); p++)
539     f ();
540 
541 #if USE_TM_CLONE_REGISTRY
542   deregister_tm_clones ();
543 #endif /* USE_TM_CLONE_REGISTRY */
544 
545 #ifdef USE_EH_FRAME_REGISTRY
546   if (__deregister_frame_info)
547     __deregister_frame_info (__EH_FRAME_BEGIN__);
548 #endif
549 }
550 
551 #if defined(USE_EH_FRAME_REGISTRY) \
552     || defined(JCR_SECTION_NAME) \
553     || defined(USE_TM_CLONE_REGISTRY)
554 /* A helper function for __do_global_ctors, which is in crtend.o.  Here
555    in crtbegin.o, we can reference a couple of symbols not visible there.
556    Plus, since we're before libgcc.a, we have no problems referencing
557    functions from there.  */
558 void
559 __do_global_ctors_1(void)
560 {
561 #ifdef USE_EH_FRAME_REGISTRY
562   static struct object object;
563   if (__register_frame_info)
564     __register_frame_info (__EH_FRAME_BEGIN__, &object);
565 #endif
566 
567 #ifdef JCR_SECTION_NAME
568   if (__JCR_LIST__[0])
569     {
570       void (*register_classes) (void *) = _Jv_RegisterClasses;
571       __asm ("" : "+r" (register_classes));
572       if (register_classes)
573 	register_classes (__JCR_LIST__);
574     }
575 #endif
576 
577 #if USE_TM_CLONE_REGISTRY
578   register_tm_clones ();
579 #endif /* USE_TM_CLONE_REGISTRY */
580 }
581 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME || USE_TM_CLONE_REGISTRY */
582 
583 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
584 #error "What are you doing with crtstuff.c, then?"
585 #endif
586 
587 #elif defined(CRT_END) /* ! CRT_BEGIN */
588 
589 /* No need for .ctors/.dtors section if linker can place them in
590    .init_array/.fini_array section.  */
591 #ifndef USE_INITFINI_ARRAY
592 /* Put a word containing zero at the end of each of our two lists of function
593    addresses.  Note that the words defined here go into the .ctors and .dtors
594    sections of the crtend.o file, and since that file is always linked in
595    last, these words naturally end up at the very ends of the two lists
596    contained in these two sections.  */
597 
598 #ifdef CTOR_LIST_END
599 CTOR_LIST_END;
600 #elif defined(CTORS_SECTION_ASM_OP)
601 /* Hack: force cc1 to switch to .data section early, so that assembling
602    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
603 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
604 asm (CTORS_SECTION_ASM_OP);
605 STATIC func_ptr __CTOR_END__[1]
606   __attribute__((aligned(sizeof(func_ptr))))
607   = { (func_ptr) 0 };
608 #else
609 STATIC func_ptr __CTOR_END__[1]
610   __attribute__((section(".ctors"), aligned(sizeof(func_ptr))))
611   = { (func_ptr) 0 };
612 #endif
613 
614 #ifdef DTOR_LIST_END
615 DTOR_LIST_END;
616 #elif defined(HIDDEN_DTOR_LIST_END)
617 #ifdef DTORS_SECTION_ASM_OP
618 asm (DTORS_SECTION_ASM_OP);
619 #endif
620 func_ptr __DTOR_END__[1]
621   __attribute__ ((used,
622 #ifndef DTORS_SECTION_ASM_OP
623 		  section(".dtors"),
624 #endif
625 		  aligned(sizeof(func_ptr)), visibility ("hidden")))
626   = { (func_ptr) 0 };
627 #elif defined(DTORS_SECTION_ASM_OP)
628 asm (DTORS_SECTION_ASM_OP);
629 STATIC func_ptr __DTOR_END__[1]
630   __attribute__ ((used, aligned(sizeof(func_ptr))))
631   = { (func_ptr) 0 };
632 #else
633 STATIC func_ptr __DTOR_END__[1]
634   __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr))))
635   = { (func_ptr) 0 };
636 #endif
637 #endif /* USE_INITFINI_ARRAY */
638 
639 #ifdef EH_FRAME_SECTION_NAME
640 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
641    this would be the 'length' field in a real FDE.  */
642 # if __INT_MAX__ == 2147483647
643 typedef int int32;
644 # elif __LONG_MAX__ == 2147483647
645 typedef long int32;
646 # elif __SHRT_MAX__ == 2147483647
647 typedef short int32;
648 # else
649 #  error "Missing a 4 byte integer"
650 # endif
651 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
652      __attribute__ ((used, section(EH_FRAME_SECTION_NAME),
653 		     aligned(sizeof(int32))))
654      = { 0 };
655 #endif /* EH_FRAME_SECTION_NAME */
656 
657 #ifdef JCR_SECTION_NAME
658 /* Null terminate the .jcr section array.  */
659 STATIC void *__JCR_END__[1]
660    __attribute__ ((used, section(JCR_SECTION_NAME),
661 		   aligned(sizeof(void *))))
662    = { 0 };
663 #endif /* JCR_SECTION_NAME */
664 
665 #if USE_TM_CLONE_REGISTRY
666 # ifndef HAVE_GAS_HIDDEN
667 static
668 # endif
669 func_ptr __TMC_END__[]
670   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void *))))
671 # ifdef HAVE_GAS_HIDDEN
672   __attribute__((__visibility__ ("hidden"))) = { };
673 # else
674   = { 0, 0 };
675 # endif
676 #endif /* USE_TM_CLONE_REGISTRY */
677 
678 #ifdef INIT_ARRAY_SECTION_ASM_OP
679 
680 /* If we are using .init_array, there is nothing to do.  */
681 
682 #elif defined(INIT_SECTION_ASM_OP)
683 
684 #ifdef OBJECT_FORMAT_ELF
685 static void __attribute__((used))
686 __do_global_ctors_aux (void)
687 {
688   func_ptr *p;
689   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
690     (*p) ();
691 }
692 
693 /* Stick a call to __do_global_ctors_aux into the .init section.  */
694 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_ctors_aux)
695 #else  /* OBJECT_FORMAT_ELF */
696 
697 /* Stick the real initialization code, followed by a normal sort of
698    function epilogue at the very end of the .init section for this
699    entire root executable file or for this entire shared library file.
700 
701    Note that we use some tricks here to get *just* the body and just
702    a function epilogue (but no function prologue) into the .init
703    section of the crtend.o file.  Specifically, we switch to the .text
704    section, start to define a function, and then we switch to the .init
705    section just before the body code.
706 
707    Earlier on, we put the corresponding function prologue into the .init
708    section of the crtbegin.o file (which will be linked in first).
709 
710    Note that we want to invoke all constructors for C++ file-scope static-
711    storage objects AFTER any other possible initialization actions which
712    may be performed by the code in the .init section contributions made by
713    other libraries, etc.  That's because those other initializations may
714    include setup operations for very primitive things (e.g. initializing
715    the state of the floating-point coprocessor, etc.) which should be done
716    before we start to execute any of the user's code.  */
717 
718 static void
719 __do_global_ctors_aux (void)	/* prologue goes in .text section */
720 {
721   asm (INIT_SECTION_ASM_OP);
722   DO_GLOBAL_CTORS_BODY;
723   atexit (__do_global_dtors);
724 }				/* epilogue and body go in .init section */
725 
726 FORCE_CODE_SECTION_ALIGN
727 asm (TEXT_SECTION_ASM_OP);
728 
729 #endif /* OBJECT_FORMAT_ELF */
730 
731 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
732 
733 extern void __do_global_ctors (void);
734 
735 /* This case is used by the Irix 6 port, which supports named sections but
736    not an SVR4-style .init section.  __do_global_ctors can be non-static
737    in this case because we protect it with -hidden_symbol.  */
738 void
739 __do_global_ctors (void)
740 {
741   func_ptr *p;
742 #if defined(USE_EH_FRAME_REGISTRY) \
743     || defined(JCR_SECTION_NAME) \
744     || defined(USE_TM_CLONE_REGISTRY)
745   __do_global_ctors_1();
746 #endif
747   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
748     (*p) ();
749 }
750 
751 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
752 #error "What are you doing with crtstuff.c, then?"
753 #endif
754 
755 #else /* ! CRT_BEGIN && ! CRT_END */
756 #error "One of CRT_BEGIN or CRT_END must be defined."
757 #endif
758